Source file src/cmd/compile/internal/ssagen/ssa.go

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package ssagen
     6  
     7  import (
     8  	"bufio"
     9  	"bytes"
    10  	"cmd/compile/internal/abi"
    11  	"fmt"
    12  	"go/constant"
    13  	"html"
    14  	"internal/buildcfg"
    15  	"os"
    16  	"path/filepath"
    17  	"sort"
    18  	"strings"
    19  
    20  	"cmd/compile/internal/base"
    21  	"cmd/compile/internal/ir"
    22  	"cmd/compile/internal/liveness"
    23  	"cmd/compile/internal/objw"
    24  	"cmd/compile/internal/reflectdata"
    25  	"cmd/compile/internal/ssa"
    26  	"cmd/compile/internal/staticdata"
    27  	"cmd/compile/internal/typecheck"
    28  	"cmd/compile/internal/types"
    29  	"cmd/internal/obj"
    30  	"cmd/internal/obj/x86"
    31  	"cmd/internal/objabi"
    32  	"cmd/internal/src"
    33  	"cmd/internal/sys"
    34  )
    35  
    36  var ssaConfig *ssa.Config
    37  var ssaCaches []ssa.Cache
    38  
    39  var ssaDump string     // early copy of $GOSSAFUNC; the func name to dump output for
    40  var ssaDir string      // optional destination for ssa dump file
    41  var ssaDumpStdout bool // whether to dump to stdout
    42  var ssaDumpCFG string  // generate CFGs for these phases
    43  const ssaDumpFile = "ssa.html"
    44  
    45  // ssaDumpInlined holds all inlined functions when ssaDump contains a function name.
    46  var ssaDumpInlined []*ir.Func
    47  
    48  func DumpInline(fn *ir.Func) {
    49  	if ssaDump != "" && ssaDump == ir.FuncName(fn) {
    50  		ssaDumpInlined = append(ssaDumpInlined, fn)
    51  	}
    52  }
    53  
    54  func InitEnv() {
    55  	ssaDump = os.Getenv("GOSSAFUNC")
    56  	ssaDir = os.Getenv("GOSSADIR")
    57  	if ssaDump != "" {
    58  		if strings.HasSuffix(ssaDump, "+") {
    59  			ssaDump = ssaDump[:len(ssaDump)-1]
    60  			ssaDumpStdout = true
    61  		}
    62  		spl := strings.Split(ssaDump, ":")
    63  		if len(spl) > 1 {
    64  			ssaDump = spl[0]
    65  			ssaDumpCFG = spl[1]
    66  		}
    67  	}
    68  }
    69  
    70  func InitConfig() {
    71  	types_ := ssa.NewTypes()
    72  
    73  	if Arch.SoftFloat {
    74  		softfloatInit()
    75  	}
    76  
    77  	// Generate a few pointer types that are uncommon in the frontend but common in the backend.
    78  	// Caching is disabled in the backend, so generating these here avoids allocations.
    79  	_ = types.NewPtr(types.Types[types.TINTER])                             // *interface{}
    80  	_ = types.NewPtr(types.NewPtr(types.Types[types.TSTRING]))              // **string
    81  	_ = types.NewPtr(types.NewSlice(types.Types[types.TINTER]))             // *[]interface{}
    82  	_ = types.NewPtr(types.NewPtr(types.ByteType))                          // **byte
    83  	_ = types.NewPtr(types.NewSlice(types.ByteType))                        // *[]byte
    84  	_ = types.NewPtr(types.NewSlice(types.Types[types.TSTRING]))            // *[]string
    85  	_ = types.NewPtr(types.NewPtr(types.NewPtr(types.Types[types.TUINT8]))) // ***uint8
    86  	_ = types.NewPtr(types.Types[types.TINT16])                             // *int16
    87  	_ = types.NewPtr(types.Types[types.TINT64])                             // *int64
    88  	_ = types.NewPtr(types.ErrorType)                                       // *error
    89  	types.NewPtrCacheEnabled = false
    90  	ssaConfig = ssa.NewConfig(base.Ctxt.Arch.Name, *types_, base.Ctxt, base.Flag.N == 0, Arch.SoftFloat)
    91  	ssaConfig.Race = base.Flag.Race
    92  	ssaCaches = make([]ssa.Cache, base.Flag.LowerC)
    93  
    94  	// Set up some runtime functions we'll need to call.
    95  	ir.Syms.AssertE2I = typecheck.LookupRuntimeFunc("assertE2I")
    96  	ir.Syms.AssertE2I2 = typecheck.LookupRuntimeFunc("assertE2I2")
    97  	ir.Syms.AssertI2I = typecheck.LookupRuntimeFunc("assertI2I")
    98  	ir.Syms.AssertI2I2 = typecheck.LookupRuntimeFunc("assertI2I2")
    99  	ir.Syms.CheckPtrAlignment = typecheck.LookupRuntimeFunc("checkptrAlignment")
   100  	ir.Syms.Deferproc = typecheck.LookupRuntimeFunc("deferproc")
   101  	ir.Syms.DeferprocStack = typecheck.LookupRuntimeFunc("deferprocStack")
   102  	ir.Syms.Deferreturn = typecheck.LookupRuntimeFunc("deferreturn")
   103  	ir.Syms.Duffcopy = typecheck.LookupRuntimeFunc("duffcopy")
   104  	ir.Syms.Duffzero = typecheck.LookupRuntimeFunc("duffzero")
   105  	ir.Syms.GCWriteBarrier = typecheck.LookupRuntimeFunc("gcWriteBarrier")
   106  	ir.Syms.Goschedguarded = typecheck.LookupRuntimeFunc("goschedguarded")
   107  	ir.Syms.Growslice = typecheck.LookupRuntimeFunc("growslice")
   108  	ir.Syms.Msanread = typecheck.LookupRuntimeFunc("msanread")
   109  	ir.Syms.Msanwrite = typecheck.LookupRuntimeFunc("msanwrite")
   110  	ir.Syms.Msanmove = typecheck.LookupRuntimeFunc("msanmove")
   111  	ir.Syms.Asanread = typecheck.LookupRuntimeFunc("asanread")
   112  	ir.Syms.Asanwrite = typecheck.LookupRuntimeFunc("asanwrite")
   113  	ir.Syms.Newobject = typecheck.LookupRuntimeFunc("newobject")
   114  	ir.Syms.Newproc = typecheck.LookupRuntimeFunc("newproc")
   115  	ir.Syms.Panicdivide = typecheck.LookupRuntimeFunc("panicdivide")
   116  	ir.Syms.PanicdottypeE = typecheck.LookupRuntimeFunc("panicdottypeE")
   117  	ir.Syms.PanicdottypeI = typecheck.LookupRuntimeFunc("panicdottypeI")
   118  	ir.Syms.Panicnildottype = typecheck.LookupRuntimeFunc("panicnildottype")
   119  	ir.Syms.Panicoverflow = typecheck.LookupRuntimeFunc("panicoverflow")
   120  	ir.Syms.Panicshift = typecheck.LookupRuntimeFunc("panicshift")
   121  	ir.Syms.Raceread = typecheck.LookupRuntimeFunc("raceread")
   122  	ir.Syms.Racereadrange = typecheck.LookupRuntimeFunc("racereadrange")
   123  	ir.Syms.Racewrite = typecheck.LookupRuntimeFunc("racewrite")
   124  	ir.Syms.Racewriterange = typecheck.LookupRuntimeFunc("racewriterange")
   125  	ir.Syms.X86HasPOPCNT = typecheck.LookupRuntimeVar("x86HasPOPCNT")       // bool
   126  	ir.Syms.X86HasSSE41 = typecheck.LookupRuntimeVar("x86HasSSE41")         // bool
   127  	ir.Syms.X86HasFMA = typecheck.LookupRuntimeVar("x86HasFMA")             // bool
   128  	ir.Syms.ARMHasVFPv4 = typecheck.LookupRuntimeVar("armHasVFPv4")         // bool
   129  	ir.Syms.ARM64HasATOMICS = typecheck.LookupRuntimeVar("arm64HasATOMICS") // bool
   130  	ir.Syms.Staticuint64s = typecheck.LookupRuntimeVar("staticuint64s")
   131  	ir.Syms.Typedmemclr = typecheck.LookupRuntimeFunc("typedmemclr")
   132  	ir.Syms.Typedmemmove = typecheck.LookupRuntimeFunc("typedmemmove")
   133  	ir.Syms.Udiv = typecheck.LookupRuntimeVar("udiv")                 // asm func with special ABI
   134  	ir.Syms.WriteBarrier = typecheck.LookupRuntimeVar("writeBarrier") // struct { bool; ... }
   135  	ir.Syms.Zerobase = typecheck.LookupRuntimeVar("zerobase")
   136  
   137  	// asm funcs with special ABI
   138  	if base.Ctxt.Arch.Name == "amd64" {
   139  		GCWriteBarrierReg = map[int16]*obj.LSym{
   140  			x86.REG_AX: typecheck.LookupRuntimeFunc("gcWriteBarrier"),
   141  			x86.REG_CX: typecheck.LookupRuntimeFunc("gcWriteBarrierCX"),
   142  			x86.REG_DX: typecheck.LookupRuntimeFunc("gcWriteBarrierDX"),
   143  			x86.REG_BX: typecheck.LookupRuntimeFunc("gcWriteBarrierBX"),
   144  			x86.REG_BP: typecheck.LookupRuntimeFunc("gcWriteBarrierBP"),
   145  			x86.REG_SI: typecheck.LookupRuntimeFunc("gcWriteBarrierSI"),
   146  			x86.REG_R8: typecheck.LookupRuntimeFunc("gcWriteBarrierR8"),
   147  			x86.REG_R9: typecheck.LookupRuntimeFunc("gcWriteBarrierR9"),
   148  		}
   149  	}
   150  
   151  	if Arch.LinkArch.Family == sys.Wasm {
   152  		BoundsCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeFunc("goPanicIndex")
   153  		BoundsCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeFunc("goPanicIndexU")
   154  		BoundsCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeFunc("goPanicSliceAlen")
   155  		BoundsCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeFunc("goPanicSliceAlenU")
   156  		BoundsCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeFunc("goPanicSliceAcap")
   157  		BoundsCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeFunc("goPanicSliceAcapU")
   158  		BoundsCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeFunc("goPanicSliceB")
   159  		BoundsCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeFunc("goPanicSliceBU")
   160  		BoundsCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeFunc("goPanicSlice3Alen")
   161  		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeFunc("goPanicSlice3AlenU")
   162  		BoundsCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeFunc("goPanicSlice3Acap")
   163  		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeFunc("goPanicSlice3AcapU")
   164  		BoundsCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeFunc("goPanicSlice3B")
   165  		BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("goPanicSlice3BU")
   166  		BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("goPanicSlice3C")
   167  		BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("goPanicSlice3CU")
   168  		BoundsCheckFunc[ssa.BoundsConvert] = typecheck.LookupRuntimeFunc("goPanicSliceConvert")
   169  	} else {
   170  		BoundsCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeFunc("panicIndex")
   171  		BoundsCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeFunc("panicIndexU")
   172  		BoundsCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeFunc("panicSliceAlen")
   173  		BoundsCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeFunc("panicSliceAlenU")
   174  		BoundsCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeFunc("panicSliceAcap")
   175  		BoundsCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeFunc("panicSliceAcapU")
   176  		BoundsCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeFunc("panicSliceB")
   177  		BoundsCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeFunc("panicSliceBU")
   178  		BoundsCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeFunc("panicSlice3Alen")
   179  		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeFunc("panicSlice3AlenU")
   180  		BoundsCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeFunc("panicSlice3Acap")
   181  		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeFunc("panicSlice3AcapU")
   182  		BoundsCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeFunc("panicSlice3B")
   183  		BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("panicSlice3BU")
   184  		BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("panicSlice3C")
   185  		BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("panicSlice3CU")
   186  		BoundsCheckFunc[ssa.BoundsConvert] = typecheck.LookupRuntimeFunc("panicSliceConvert")
   187  	}
   188  	if Arch.LinkArch.PtrSize == 4 {
   189  		ExtendCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeVar("panicExtendIndex")
   190  		ExtendCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeVar("panicExtendIndexU")
   191  		ExtendCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeVar("panicExtendSliceAlen")
   192  		ExtendCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeVar("panicExtendSliceAlenU")
   193  		ExtendCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeVar("panicExtendSliceAcap")
   194  		ExtendCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeVar("panicExtendSliceAcapU")
   195  		ExtendCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeVar("panicExtendSliceB")
   196  		ExtendCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeVar("panicExtendSliceBU")
   197  		ExtendCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeVar("panicExtendSlice3Alen")
   198  		ExtendCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeVar("panicExtendSlice3AlenU")
   199  		ExtendCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeVar("panicExtendSlice3Acap")
   200  		ExtendCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeVar("panicExtendSlice3AcapU")
   201  		ExtendCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeVar("panicExtendSlice3B")
   202  		ExtendCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeVar("panicExtendSlice3BU")
   203  		ExtendCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeVar("panicExtendSlice3C")
   204  		ExtendCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeVar("panicExtendSlice3CU")
   205  	}
   206  
   207  	// Wasm (all asm funcs with special ABIs)
   208  	ir.Syms.WasmMove = typecheck.LookupRuntimeVar("wasmMove")
   209  	ir.Syms.WasmZero = typecheck.LookupRuntimeVar("wasmZero")
   210  	ir.Syms.WasmDiv = typecheck.LookupRuntimeVar("wasmDiv")
   211  	ir.Syms.WasmTruncS = typecheck.LookupRuntimeVar("wasmTruncS")
   212  	ir.Syms.WasmTruncU = typecheck.LookupRuntimeVar("wasmTruncU")
   213  	ir.Syms.SigPanic = typecheck.LookupRuntimeFunc("sigpanic")
   214  }
   215  
   216  // AbiForBodylessFuncStackMap returns the ABI for a bodyless function's stack map.
   217  // This is not necessarily the ABI used to call it.
   218  // Currently (1.17 dev) such a stack map is always ABI0;
   219  // any ABI wrapper that is present is nosplit, hence a precise
   220  // stack map is not needed there (the parameters survive only long
   221  // enough to call the wrapped assembly function).
   222  // This always returns a freshly copied ABI.
   223  func AbiForBodylessFuncStackMap(fn *ir.Func) *abi.ABIConfig {
   224  	return ssaConfig.ABI0.Copy() // No idea what races will result, be safe
   225  }
   226  
   227  // These are disabled but remain ready for use in case they are needed for the next regabi port.
   228  // TODO if they are not needed for 1.18 / next register abi port, delete them.
   229  const magicNameDotSuffix = ".*disabled*MagicMethodNameForTestingRegisterABI"
   230  const magicLastTypeName = "*disabled*MagicLastTypeNameForTestingRegisterABI"
   231  
   232  // abiForFunc implements ABI policy for a function, but does not return a copy of the ABI.
   233  // Passing a nil function returns the default ABI based on experiment configuration.
   234  func abiForFunc(fn *ir.Func, abi0, abi1 *abi.ABIConfig) *abi.ABIConfig {
   235  	if buildcfg.Experiment.RegabiArgs {
   236  		// Select the ABI based on the function's defining ABI.
   237  		if fn == nil {
   238  			return abi1
   239  		}
   240  		switch fn.ABI {
   241  		case obj.ABI0:
   242  			return abi0
   243  		case obj.ABIInternal:
   244  			// TODO(austin): Clean up the nomenclature here.
   245  			// It's not clear that "abi1" is ABIInternal.
   246  			return abi1
   247  		}
   248  		base.Fatalf("function %v has unknown ABI %v", fn, fn.ABI)
   249  		panic("not reachable")
   250  	}
   251  
   252  	a := abi0
   253  	if fn != nil {
   254  		name := ir.FuncName(fn)
   255  		magicName := strings.HasSuffix(name, magicNameDotSuffix)
   256  		if fn.Pragma&ir.RegisterParams != 0 { // TODO(register args) remove after register abi is working
   257  			if strings.Contains(name, ".") {
   258  				if !magicName {
   259  					base.ErrorfAt(fn.Pos(), "Calls to //go:registerparams method %s won't work, remove the pragma from the declaration.", name)
   260  				}
   261  			}
   262  			a = abi1
   263  		} else if magicName {
   264  			if base.FmtPos(fn.Pos()) == "<autogenerated>:1" {
   265  				// no way to put a pragma here, and it will error out in the real source code if they did not do it there.
   266  				a = abi1
   267  			} else {
   268  				base.ErrorfAt(fn.Pos(), "Methods with magic name %s (method %s) must also specify //go:registerparams", magicNameDotSuffix[1:], name)
   269  			}
   270  		}
   271  		if regAbiForFuncType(fn.Type().FuncType()) {
   272  			// fmt.Printf("Saw magic last type name for function %s\n", name)
   273  			a = abi1
   274  		}
   275  	}
   276  	return a
   277  }
   278  
   279  func regAbiForFuncType(ft *types.Func) bool {
   280  	np := ft.Params.NumFields()
   281  	return np > 0 && strings.Contains(ft.Params.FieldType(np-1).String(), magicLastTypeName)
   282  }
   283  
   284  // dvarint writes a varint v to the funcdata in symbol x and returns the new offset
   285  func dvarint(x *obj.LSym, off int, v int64) int {
   286  	if v < 0 || v > 1e9 {
   287  		panic(fmt.Sprintf("dvarint: bad offset for funcdata - %v", v))
   288  	}
   289  	if v < 1<<7 {
   290  		return objw.Uint8(x, off, uint8(v))
   291  	}
   292  	off = objw.Uint8(x, off, uint8((v&127)|128))
   293  	if v < 1<<14 {
   294  		return objw.Uint8(x, off, uint8(v>>7))
   295  	}
   296  	off = objw.Uint8(x, off, uint8(((v>>7)&127)|128))
   297  	if v < 1<<21 {
   298  		return objw.Uint8(x, off, uint8(v>>14))
   299  	}
   300  	off = objw.Uint8(x, off, uint8(((v>>14)&127)|128))
   301  	if v < 1<<28 {
   302  		return objw.Uint8(x, off, uint8(v>>21))
   303  	}
   304  	off = objw.Uint8(x, off, uint8(((v>>21)&127)|128))
   305  	return objw.Uint8(x, off, uint8(v>>28))
   306  }
   307  
   308  // emitOpenDeferInfo emits FUNCDATA information about the defers in a function
   309  // that is using open-coded defers.  This funcdata is used to determine the active
   310  // defers in a function and execute those defers during panic processing.
   311  //
   312  // The funcdata is all encoded in varints (since values will almost always be less than
   313  // 128, but stack offsets could potentially be up to 2Gbyte). All "locations" (offsets)
   314  // for stack variables are specified as the number of bytes below varp (pointer to the
   315  // top of the local variables) for their starting address. The format is:
   316  //
   317  //  - Offset of the deferBits variable
   318  //  - Number of defers in the function
   319  //  - Information about each defer call, in reverse order of appearance in the function:
   320  //    - Offset of the closure value to call
   321  func (s *state) emitOpenDeferInfo() {
   322  	x := base.Ctxt.Lookup(s.curfn.LSym.Name + ".opendefer")
   323  	x.Set(obj.AttrContentAddressable, true)
   324  	s.curfn.LSym.Func().OpenCodedDeferInfo = x
   325  	off := 0
   326  	off = dvarint(x, off, -s.deferBitsTemp.FrameOffset())
   327  	off = dvarint(x, off, int64(len(s.openDefers)))
   328  
   329  	// Write in reverse-order, for ease of running in that order at runtime
   330  	for i := len(s.openDefers) - 1; i >= 0; i-- {
   331  		r := s.openDefers[i]
   332  		off = dvarint(x, off, -r.closureNode.FrameOffset())
   333  	}
   334  }
   335  
   336  func okOffset(offset int64) int64 {
   337  	if offset == types.BOGUS_FUNARG_OFFSET {
   338  		panic(fmt.Errorf("Bogus offset %d", offset))
   339  	}
   340  	return offset
   341  }
   342  
   343  // buildssa builds an SSA function for fn.
   344  // worker indicates which of the backend workers is doing the processing.
   345  func buildssa(fn *ir.Func, worker int) *ssa.Func {
   346  	name := ir.FuncName(fn)
   347  	printssa := false
   348  	if ssaDump != "" { // match either a simple name e.g. "(*Reader).Reset", package.name e.g. "compress/gzip.(*Reader).Reset", or subpackage name "gzip.(*Reader).Reset"
   349  		pkgDotName := base.Ctxt.Pkgpath + "." + name
   350  		printssa = name == ssaDump ||
   351  			strings.HasSuffix(pkgDotName, ssaDump) && (pkgDotName == ssaDump || strings.HasSuffix(pkgDotName, "/"+ssaDump))
   352  	}
   353  	var astBuf *bytes.Buffer
   354  	if printssa {
   355  		astBuf = &bytes.Buffer{}
   356  		ir.FDumpList(astBuf, "buildssa-enter", fn.Enter)
   357  		ir.FDumpList(astBuf, "buildssa-body", fn.Body)
   358  		ir.FDumpList(astBuf, "buildssa-exit", fn.Exit)
   359  		if ssaDumpStdout {
   360  			fmt.Println("generating SSA for", name)
   361  			fmt.Print(astBuf.String())
   362  		}
   363  	}
   364  
   365  	var s state
   366  	s.pushLine(fn.Pos())
   367  	defer s.popLine()
   368  
   369  	s.hasdefer = fn.HasDefer()
   370  	if fn.Pragma&ir.CgoUnsafeArgs != 0 {
   371  		s.cgoUnsafeArgs = true
   372  	}
   373  	s.checkPtrEnabled = ir.ShouldCheckPtr(fn, 1)
   374  
   375  	fe := ssafn{
   376  		curfn: fn,
   377  		log:   printssa && ssaDumpStdout,
   378  	}
   379  	s.curfn = fn
   380  
   381  	s.f = ssa.NewFunc(&fe)
   382  	s.config = ssaConfig
   383  	s.f.Type = fn.Type()
   384  	s.f.Config = ssaConfig
   385  	s.f.Cache = &ssaCaches[worker]
   386  	s.f.Cache.Reset()
   387  	s.f.Name = name
   388  	s.f.DebugTest = s.f.DebugHashMatch("GOSSAHASH")
   389  	s.f.PrintOrHtmlSSA = printssa
   390  	if fn.Pragma&ir.Nosplit != 0 {
   391  		s.f.NoSplit = true
   392  	}
   393  	s.f.ABI0 = ssaConfig.ABI0.Copy() // Make a copy to avoid racy map operations in type-register-width cache.
   394  	s.f.ABI1 = ssaConfig.ABI1.Copy()
   395  	s.f.ABIDefault = abiForFunc(nil, s.f.ABI0, s.f.ABI1)
   396  	s.f.ABISelf = abiForFunc(fn, s.f.ABI0, s.f.ABI1)
   397  
   398  	s.panics = map[funcLine]*ssa.Block{}
   399  	s.softFloat = s.config.SoftFloat
   400  
   401  	// Allocate starting block
   402  	s.f.Entry = s.f.NewBlock(ssa.BlockPlain)
   403  	s.f.Entry.Pos = fn.Pos()
   404  
   405  	if printssa {
   406  		ssaDF := ssaDumpFile
   407  		if ssaDir != "" {
   408  			ssaDF = filepath.Join(ssaDir, base.Ctxt.Pkgpath+"."+name+".html")
   409  			ssaD := filepath.Dir(ssaDF)
   410  			os.MkdirAll(ssaD, 0755)
   411  		}
   412  		s.f.HTMLWriter = ssa.NewHTMLWriter(ssaDF, s.f, ssaDumpCFG)
   413  		// TODO: generate and print a mapping from nodes to values and blocks
   414  		dumpSourcesColumn(s.f.HTMLWriter, fn)
   415  		s.f.HTMLWriter.WriteAST("AST", astBuf)
   416  	}
   417  
   418  	// Allocate starting values
   419  	s.labels = map[string]*ssaLabel{}
   420  	s.fwdVars = map[ir.Node]*ssa.Value{}
   421  	s.startmem = s.entryNewValue0(ssa.OpInitMem, types.TypeMem)
   422  
   423  	s.hasOpenDefers = base.Flag.N == 0 && s.hasdefer && !s.curfn.OpenCodedDeferDisallowed()
   424  	switch {
   425  	case base.Debug.NoOpenDefer != 0:
   426  		s.hasOpenDefers = false
   427  	case s.hasOpenDefers && (base.Ctxt.Flag_shared || base.Ctxt.Flag_dynlink) && base.Ctxt.Arch.Name == "386":
   428  		// Don't support open-coded defers for 386 ONLY when using shared
   429  		// libraries, because there is extra code (added by rewriteToUseGot())
   430  		// preceding the deferreturn/ret code that we don't track correctly.
   431  		s.hasOpenDefers = false
   432  	}
   433  	if s.hasOpenDefers && len(s.curfn.Exit) > 0 {
   434  		// Skip doing open defers if there is any extra exit code (likely
   435  		// race detection), since we will not generate that code in the
   436  		// case of the extra deferreturn/ret segment.
   437  		s.hasOpenDefers = false
   438  	}
   439  	if s.hasOpenDefers {
   440  		// Similarly, skip if there are any heap-allocated result
   441  		// parameters that need to be copied back to their stack slots.
   442  		for _, f := range s.curfn.Type().Results().FieldSlice() {
   443  			if !f.Nname.(*ir.Name).OnStack() {
   444  				s.hasOpenDefers = false
   445  				break
   446  			}
   447  		}
   448  	}
   449  	if s.hasOpenDefers &&
   450  		s.curfn.NumReturns*s.curfn.NumDefers > 15 {
   451  		// Since we are generating defer calls at every exit for
   452  		// open-coded defers, skip doing open-coded defers if there are
   453  		// too many returns (especially if there are multiple defers).
   454  		// Open-coded defers are most important for improving performance
   455  		// for smaller functions (which don't have many returns).
   456  		s.hasOpenDefers = false
   457  	}
   458  
   459  	s.sp = s.entryNewValue0(ssa.OpSP, types.Types[types.TUINTPTR]) // TODO: use generic pointer type (unsafe.Pointer?) instead
   460  	s.sb = s.entryNewValue0(ssa.OpSB, types.Types[types.TUINTPTR])
   461  
   462  	s.startBlock(s.f.Entry)
   463  	s.vars[memVar] = s.startmem
   464  	if s.hasOpenDefers {
   465  		// Create the deferBits variable and stack slot.  deferBits is a
   466  		// bitmask showing which of the open-coded defers in this function
   467  		// have been activated.
   468  		deferBitsTemp := typecheck.TempAt(src.NoXPos, s.curfn, types.Types[types.TUINT8])
   469  		deferBitsTemp.SetAddrtaken(true)
   470  		s.deferBitsTemp = deferBitsTemp
   471  		// For this value, AuxInt is initialized to zero by default
   472  		startDeferBits := s.entryNewValue0(ssa.OpConst8, types.Types[types.TUINT8])
   473  		s.vars[deferBitsVar] = startDeferBits
   474  		s.deferBitsAddr = s.addr(deferBitsTemp)
   475  		s.store(types.Types[types.TUINT8], s.deferBitsAddr, startDeferBits)
   476  		// Make sure that the deferBits stack slot is kept alive (for use
   477  		// by panics) and stores to deferBits are not eliminated, even if
   478  		// all checking code on deferBits in the function exit can be
   479  		// eliminated, because the defer statements were all
   480  		// unconditional.
   481  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, deferBitsTemp, s.mem(), false)
   482  	}
   483  
   484  	var params *abi.ABIParamResultInfo
   485  	params = s.f.ABISelf.ABIAnalyze(fn.Type(), true)
   486  
   487  	// The backend's stackframe pass prunes away entries from the fn's
   488  	// Dcl list, including PARAMOUT nodes that correspond to output
   489  	// params passed in registers. Walk the Dcl list and capture these
   490  	// nodes to a side list, so that we'll have them available during
   491  	// DWARF-gen later on. See issue 48573 for more details.
   492  	var debugInfo ssa.FuncDebug
   493  	for _, n := range fn.Dcl {
   494  		if n.Class == ir.PPARAMOUT && n.IsOutputParamInRegisters() {
   495  			debugInfo.RegOutputParams = append(debugInfo.RegOutputParams, n)
   496  		}
   497  	}
   498  	fn.DebugInfo = &debugInfo
   499  
   500  	// Generate addresses of local declarations
   501  	s.decladdrs = map[*ir.Name]*ssa.Value{}
   502  	for _, n := range fn.Dcl {
   503  		switch n.Class {
   504  		case ir.PPARAM:
   505  			// Be aware that blank and unnamed input parameters will not appear here, but do appear in the type
   506  			s.decladdrs[n] = s.entryNewValue2A(ssa.OpLocalAddr, types.NewPtr(n.Type()), n, s.sp, s.startmem)
   507  		case ir.PPARAMOUT:
   508  			s.decladdrs[n] = s.entryNewValue2A(ssa.OpLocalAddr, types.NewPtr(n.Type()), n, s.sp, s.startmem)
   509  		case ir.PAUTO:
   510  			// processed at each use, to prevent Addr coming
   511  			// before the decl.
   512  		default:
   513  			s.Fatalf("local variable with class %v unimplemented", n.Class)
   514  		}
   515  	}
   516  
   517  	s.f.OwnAux = ssa.OwnAuxCall(fn.LSym, params)
   518  
   519  	// Populate SSAable arguments.
   520  	for _, n := range fn.Dcl {
   521  		if n.Class == ir.PPARAM {
   522  			if s.canSSA(n) {
   523  				v := s.newValue0A(ssa.OpArg, n.Type(), n)
   524  				s.vars[n] = v
   525  				s.addNamedValue(n, v) // This helps with debugging information, not needed for compilation itself.
   526  			} else { // address was taken AND/OR too large for SSA
   527  				paramAssignment := ssa.ParamAssignmentForArgName(s.f, n)
   528  				if len(paramAssignment.Registers) > 0 {
   529  					if TypeOK(n.Type()) { // SSA-able type, so address was taken -- receive value in OpArg, DO NOT bind to var, store immediately to memory.
   530  						v := s.newValue0A(ssa.OpArg, n.Type(), n)
   531  						s.store(n.Type(), s.decladdrs[n], v)
   532  					} else { // Too big for SSA.
   533  						// Brute force, and early, do a bunch of stores from registers
   534  						// TODO fix the nasty storeArgOrLoad recursion in ssa/expand_calls.go so this Just Works with store of a big Arg.
   535  						s.storeParameterRegsToStack(s.f.ABISelf, paramAssignment, n, s.decladdrs[n], false)
   536  					}
   537  				}
   538  			}
   539  		}
   540  	}
   541  
   542  	// Populate closure variables.
   543  	if fn.Needctxt() {
   544  		clo := s.entryNewValue0(ssa.OpGetClosurePtr, s.f.Config.Types.BytePtr)
   545  		offset := int64(types.PtrSize) // PtrSize to skip past function entry PC field
   546  		for _, n := range fn.ClosureVars {
   547  			typ := n.Type()
   548  			if !n.Byval() {
   549  				typ = types.NewPtr(typ)
   550  			}
   551  
   552  			offset = types.Rnd(offset, typ.Alignment())
   553  			ptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(typ), offset, clo)
   554  			offset += typ.Size()
   555  
   556  			// If n is a small variable captured by value, promote
   557  			// it to PAUTO so it can be converted to SSA.
   558  			//
   559  			// Note: While we never capture a variable by value if
   560  			// the user took its address, we may have generated
   561  			// runtime calls that did (#43701). Since we don't
   562  			// convert Addrtaken variables to SSA anyway, no point
   563  			// in promoting them either.
   564  			if n.Byval() && !n.Addrtaken() && TypeOK(n.Type()) {
   565  				n.Class = ir.PAUTO
   566  				fn.Dcl = append(fn.Dcl, n)
   567  				s.assign(n, s.load(n.Type(), ptr), false, 0)
   568  				continue
   569  			}
   570  
   571  			if !n.Byval() {
   572  				ptr = s.load(typ, ptr)
   573  			}
   574  			s.setHeapaddr(fn.Pos(), n, ptr)
   575  		}
   576  	}
   577  
   578  	// Convert the AST-based IR to the SSA-based IR
   579  	s.stmtList(fn.Enter)
   580  	s.zeroResults()
   581  	s.paramsToHeap()
   582  	s.stmtList(fn.Body)
   583  
   584  	// fallthrough to exit
   585  	if s.curBlock != nil {
   586  		s.pushLine(fn.Endlineno)
   587  		s.exit()
   588  		s.popLine()
   589  	}
   590  
   591  	for _, b := range s.f.Blocks {
   592  		if b.Pos != src.NoXPos {
   593  			s.updateUnsetPredPos(b)
   594  		}
   595  	}
   596  
   597  	s.f.HTMLWriter.WritePhase("before insert phis", "before insert phis")
   598  
   599  	s.insertPhis()
   600  
   601  	// Main call to ssa package to compile function
   602  	ssa.Compile(s.f)
   603  
   604  	if s.hasOpenDefers {
   605  		s.emitOpenDeferInfo()
   606  	}
   607  
   608  	// Record incoming parameter spill information for morestack calls emitted in the assembler.
   609  	// This is done here, using all the parameters (used, partially used, and unused) because
   610  	// it mimics the behavior of the former ABI (everything stored) and because it's not 100%
   611  	// clear if naming conventions are respected in autogenerated code.
   612  	// TODO figure out exactly what's unused, don't spill it. Make liveness fine-grained, also.
   613  	for _, p := range params.InParams() {
   614  		typs, offs := p.RegisterTypesAndOffsets()
   615  		for i, t := range typs {
   616  			o := offs[i]                // offset within parameter
   617  			fo := p.FrameOffset(params) // offset of parameter in frame
   618  			reg := ssa.ObjRegForAbiReg(p.Registers[i], s.f.Config)
   619  			s.f.RegArgs = append(s.f.RegArgs, ssa.Spill{Reg: reg, Offset: fo + o, Type: t})
   620  		}
   621  	}
   622  
   623  	return s.f
   624  }
   625  
   626  func (s *state) storeParameterRegsToStack(abi *abi.ABIConfig, paramAssignment *abi.ABIParamAssignment, n *ir.Name, addr *ssa.Value, pointersOnly bool) {
   627  	typs, offs := paramAssignment.RegisterTypesAndOffsets()
   628  	for i, t := range typs {
   629  		if pointersOnly && !t.IsPtrShaped() {
   630  			continue
   631  		}
   632  		r := paramAssignment.Registers[i]
   633  		o := offs[i]
   634  		op, reg := ssa.ArgOpAndRegisterFor(r, abi)
   635  		aux := &ssa.AuxNameOffset{Name: n, Offset: o}
   636  		v := s.newValue0I(op, t, reg)
   637  		v.Aux = aux
   638  		p := s.newValue1I(ssa.OpOffPtr, types.NewPtr(t), o, addr)
   639  		s.store(t, p, v)
   640  	}
   641  }
   642  
   643  // zeroResults zeros the return values at the start of the function.
   644  // We need to do this very early in the function.  Defer might stop a
   645  // panic and show the return values as they exist at the time of
   646  // panic.  For precise stacks, the garbage collector assumes results
   647  // are always live, so we need to zero them before any allocations,
   648  // even allocations to move params/results to the heap.
   649  func (s *state) zeroResults() {
   650  	for _, f := range s.curfn.Type().Results().FieldSlice() {
   651  		n := f.Nname.(*ir.Name)
   652  		if !n.OnStack() {
   653  			// The local which points to the return value is the
   654  			// thing that needs zeroing. This is already handled
   655  			// by a Needzero annotation in plive.go:(*liveness).epilogue.
   656  			continue
   657  		}
   658  		// Zero the stack location containing f.
   659  		if typ := n.Type(); TypeOK(typ) {
   660  			s.assign(n, s.zeroVal(typ), false, 0)
   661  		} else {
   662  			s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
   663  			s.zero(n.Type(), s.decladdrs[n])
   664  		}
   665  	}
   666  }
   667  
   668  // paramsToHeap produces code to allocate memory for heap-escaped parameters
   669  // and to copy non-result parameters' values from the stack.
   670  func (s *state) paramsToHeap() {
   671  	do := func(params *types.Type) {
   672  		for _, f := range params.FieldSlice() {
   673  			if f.Nname == nil {
   674  				continue // anonymous or blank parameter
   675  			}
   676  			n := f.Nname.(*ir.Name)
   677  			if ir.IsBlank(n) || n.OnStack() {
   678  				continue
   679  			}
   680  			s.newHeapaddr(n)
   681  			if n.Class == ir.PPARAM {
   682  				s.move(n.Type(), s.expr(n.Heapaddr), s.decladdrs[n])
   683  			}
   684  		}
   685  	}
   686  
   687  	typ := s.curfn.Type()
   688  	do(typ.Recvs())
   689  	do(typ.Params())
   690  	do(typ.Results())
   691  }
   692  
   693  // newHeapaddr allocates heap memory for n and sets its heap address.
   694  func (s *state) newHeapaddr(n *ir.Name) {
   695  	s.setHeapaddr(n.Pos(), n, s.newObject(n.Type()))
   696  }
   697  
   698  // setHeapaddr allocates a new PAUTO variable to store ptr (which must be non-nil)
   699  // and then sets it as n's heap address.
   700  func (s *state) setHeapaddr(pos src.XPos, n *ir.Name, ptr *ssa.Value) {
   701  	if !ptr.Type.IsPtr() || !types.Identical(n.Type(), ptr.Type.Elem()) {
   702  		base.FatalfAt(n.Pos(), "setHeapaddr %L with type %v", n, ptr.Type)
   703  	}
   704  
   705  	// Declare variable to hold address.
   706  	addr := ir.NewNameAt(pos, &types.Sym{Name: "&" + n.Sym().Name, Pkg: types.LocalPkg})
   707  	addr.SetType(types.NewPtr(n.Type()))
   708  	addr.Class = ir.PAUTO
   709  	addr.SetUsed(true)
   710  	addr.Curfn = s.curfn
   711  	s.curfn.Dcl = append(s.curfn.Dcl, addr)
   712  	types.CalcSize(addr.Type())
   713  
   714  	if n.Class == ir.PPARAMOUT {
   715  		addr.SetIsOutputParamHeapAddr(true)
   716  	}
   717  
   718  	n.Heapaddr = addr
   719  	s.assign(addr, ptr, false, 0)
   720  }
   721  
   722  // newObject returns an SSA value denoting new(typ).
   723  func (s *state) newObject(typ *types.Type) *ssa.Value {
   724  	if typ.Size() == 0 {
   725  		return s.newValue1A(ssa.OpAddr, types.NewPtr(typ), ir.Syms.Zerobase, s.sb)
   726  	}
   727  	return s.rtcall(ir.Syms.Newobject, true, []*types.Type{types.NewPtr(typ)}, s.reflectType(typ))[0]
   728  }
   729  
   730  func (s *state) checkPtrAlignment(n *ir.ConvExpr, v *ssa.Value, count *ssa.Value) {
   731  	if !n.Type().IsPtr() {
   732  		s.Fatalf("expected pointer type: %v", n.Type())
   733  	}
   734  	elem := n.Type().Elem()
   735  	if count != nil {
   736  		if !elem.IsArray() {
   737  			s.Fatalf("expected array type: %v", elem)
   738  		}
   739  		elem = elem.Elem()
   740  	}
   741  	size := elem.Size()
   742  	// Casting from larger type to smaller one is ok, so for smallest type, do nothing.
   743  	if elem.Alignment() == 1 && (size == 0 || size == 1 || count == nil) {
   744  		return
   745  	}
   746  	if count == nil {
   747  		count = s.constInt(types.Types[types.TUINTPTR], 1)
   748  	}
   749  	if count.Type.Size() != s.config.PtrSize {
   750  		s.Fatalf("expected count fit to an uintptr size, have: %d, want: %d", count.Type.Size(), s.config.PtrSize)
   751  	}
   752  	s.rtcall(ir.Syms.CheckPtrAlignment, true, nil, v, s.reflectType(elem), count)
   753  }
   754  
   755  // reflectType returns an SSA value representing a pointer to typ's
   756  // reflection type descriptor.
   757  func (s *state) reflectType(typ *types.Type) *ssa.Value {
   758  	lsym := reflectdata.TypeLinksym(typ)
   759  	return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(types.Types[types.TUINT8]), lsym, s.sb)
   760  }
   761  
   762  func dumpSourcesColumn(writer *ssa.HTMLWriter, fn *ir.Func) {
   763  	// Read sources of target function fn.
   764  	fname := base.Ctxt.PosTable.Pos(fn.Pos()).Filename()
   765  	targetFn, err := readFuncLines(fname, fn.Pos().Line(), fn.Endlineno.Line())
   766  	if err != nil {
   767  		writer.Logf("cannot read sources for function %v: %v", fn, err)
   768  	}
   769  
   770  	// Read sources of inlined functions.
   771  	var inlFns []*ssa.FuncLines
   772  	for _, fi := range ssaDumpInlined {
   773  		elno := fi.Endlineno
   774  		fname := base.Ctxt.PosTable.Pos(fi.Pos()).Filename()
   775  		fnLines, err := readFuncLines(fname, fi.Pos().Line(), elno.Line())
   776  		if err != nil {
   777  			writer.Logf("cannot read sources for inlined function %v: %v", fi, err)
   778  			continue
   779  		}
   780  		inlFns = append(inlFns, fnLines)
   781  	}
   782  
   783  	sort.Sort(ssa.ByTopo(inlFns))
   784  	if targetFn != nil {
   785  		inlFns = append([]*ssa.FuncLines{targetFn}, inlFns...)
   786  	}
   787  
   788  	writer.WriteSources("sources", inlFns)
   789  }
   790  
   791  func readFuncLines(file string, start, end uint) (*ssa.FuncLines, error) {
   792  	f, err := os.Open(os.ExpandEnv(file))
   793  	if err != nil {
   794  		return nil, err
   795  	}
   796  	defer f.Close()
   797  	var lines []string
   798  	ln := uint(1)
   799  	scanner := bufio.NewScanner(f)
   800  	for scanner.Scan() && ln <= end {
   801  		if ln >= start {
   802  			lines = append(lines, scanner.Text())
   803  		}
   804  		ln++
   805  	}
   806  	return &ssa.FuncLines{Filename: file, StartLineno: start, Lines: lines}, nil
   807  }
   808  
   809  // updateUnsetPredPos propagates the earliest-value position information for b
   810  // towards all of b's predecessors that need a position, and recurs on that
   811  // predecessor if its position is updated. B should have a non-empty position.
   812  func (s *state) updateUnsetPredPos(b *ssa.Block) {
   813  	if b.Pos == src.NoXPos {
   814  		s.Fatalf("Block %s should have a position", b)
   815  	}
   816  	bestPos := src.NoXPos
   817  	for _, e := range b.Preds {
   818  		p := e.Block()
   819  		if !p.LackingPos() {
   820  			continue
   821  		}
   822  		if bestPos == src.NoXPos {
   823  			bestPos = b.Pos
   824  			for _, v := range b.Values {
   825  				if v.LackingPos() {
   826  					continue
   827  				}
   828  				if v.Pos != src.NoXPos {
   829  					// Assume values are still in roughly textual order;
   830  					// TODO: could also seek minimum position?
   831  					bestPos = v.Pos
   832  					break
   833  				}
   834  			}
   835  		}
   836  		p.Pos = bestPos
   837  		s.updateUnsetPredPos(p) // We do not expect long chains of these, thus recursion is okay.
   838  	}
   839  }
   840  
   841  // Information about each open-coded defer.
   842  type openDeferInfo struct {
   843  	// The node representing the call of the defer
   844  	n *ir.CallExpr
   845  	// If defer call is closure call, the address of the argtmp where the
   846  	// closure is stored.
   847  	closure *ssa.Value
   848  	// The node representing the argtmp where the closure is stored - used for
   849  	// function, method, or interface call, to store a closure that panic
   850  	// processing can use for this defer.
   851  	closureNode *ir.Name
   852  }
   853  
   854  type state struct {
   855  	// configuration (arch) information
   856  	config *ssa.Config
   857  
   858  	// function we're building
   859  	f *ssa.Func
   860  
   861  	// Node for function
   862  	curfn *ir.Func
   863  
   864  	// labels in f
   865  	labels map[string]*ssaLabel
   866  
   867  	// unlabeled break and continue statement tracking
   868  	breakTo    *ssa.Block // current target for plain break statement
   869  	continueTo *ssa.Block // current target for plain continue statement
   870  
   871  	// current location where we're interpreting the AST
   872  	curBlock *ssa.Block
   873  
   874  	// variable assignments in the current block (map from variable symbol to ssa value)
   875  	// *Node is the unique identifier (an ONAME Node) for the variable.
   876  	// TODO: keep a single varnum map, then make all of these maps slices instead?
   877  	vars map[ir.Node]*ssa.Value
   878  
   879  	// fwdVars are variables that are used before they are defined in the current block.
   880  	// This map exists just to coalesce multiple references into a single FwdRef op.
   881  	// *Node is the unique identifier (an ONAME Node) for the variable.
   882  	fwdVars map[ir.Node]*ssa.Value
   883  
   884  	// all defined variables at the end of each block. Indexed by block ID.
   885  	defvars []map[ir.Node]*ssa.Value
   886  
   887  	// addresses of PPARAM and PPARAMOUT variables on the stack.
   888  	decladdrs map[*ir.Name]*ssa.Value
   889  
   890  	// starting values. Memory, stack pointer, and globals pointer
   891  	startmem *ssa.Value
   892  	sp       *ssa.Value
   893  	sb       *ssa.Value
   894  	// value representing address of where deferBits autotmp is stored
   895  	deferBitsAddr *ssa.Value
   896  	deferBitsTemp *ir.Name
   897  
   898  	// line number stack. The current line number is top of stack
   899  	line []src.XPos
   900  	// the last line number processed; it may have been popped
   901  	lastPos src.XPos
   902  
   903  	// list of panic calls by function name and line number.
   904  	// Used to deduplicate panic calls.
   905  	panics map[funcLine]*ssa.Block
   906  
   907  	cgoUnsafeArgs   bool
   908  	hasdefer        bool // whether the function contains a defer statement
   909  	softFloat       bool
   910  	hasOpenDefers   bool // whether we are doing open-coded defers
   911  	checkPtrEnabled bool // whether to insert checkptr instrumentation
   912  
   913  	// If doing open-coded defers, list of info about the defer calls in
   914  	// scanning order. Hence, at exit we should run these defers in reverse
   915  	// order of this list
   916  	openDefers []*openDeferInfo
   917  	// For open-coded defers, this is the beginning and end blocks of the last
   918  	// defer exit code that we have generated so far. We use these to share
   919  	// code between exits if the shareDeferExits option (disabled by default)
   920  	// is on.
   921  	lastDeferExit       *ssa.Block // Entry block of last defer exit code we generated
   922  	lastDeferFinalBlock *ssa.Block // Final block of last defer exit code we generated
   923  	lastDeferCount      int        // Number of defers encountered at that point
   924  
   925  	prevCall *ssa.Value // the previous call; use this to tie results to the call op.
   926  }
   927  
   928  type funcLine struct {
   929  	f    *obj.LSym
   930  	base *src.PosBase
   931  	line uint
   932  }
   933  
   934  type ssaLabel struct {
   935  	target         *ssa.Block // block identified by this label
   936  	breakTarget    *ssa.Block // block to break to in control flow node identified by this label
   937  	continueTarget *ssa.Block // block to continue to in control flow node identified by this label
   938  }
   939  
   940  // label returns the label associated with sym, creating it if necessary.
   941  func (s *state) label(sym *types.Sym) *ssaLabel {
   942  	lab := s.labels[sym.Name]
   943  	if lab == nil {
   944  		lab = new(ssaLabel)
   945  		s.labels[sym.Name] = lab
   946  	}
   947  	return lab
   948  }
   949  
   950  func (s *state) Logf(msg string, args ...interface{}) { s.f.Logf(msg, args...) }
   951  func (s *state) Log() bool                            { return s.f.Log() }
   952  func (s *state) Fatalf(msg string, args ...interface{}) {
   953  	s.f.Frontend().Fatalf(s.peekPos(), msg, args...)
   954  }
   955  func (s *state) Warnl(pos src.XPos, msg string, args ...interface{}) { s.f.Warnl(pos, msg, args...) }
   956  func (s *state) Debug_checknil() bool                                { return s.f.Frontend().Debug_checknil() }
   957  
   958  func ssaMarker(name string) *ir.Name {
   959  	return typecheck.NewName(&types.Sym{Name: name})
   960  }
   961  
   962  var (
   963  	// marker node for the memory variable
   964  	memVar = ssaMarker("mem")
   965  
   966  	// marker nodes for temporary variables
   967  	ptrVar       = ssaMarker("ptr")
   968  	lenVar       = ssaMarker("len")
   969  	newlenVar    = ssaMarker("newlen")
   970  	capVar       = ssaMarker("cap")
   971  	typVar       = ssaMarker("typ")
   972  	okVar        = ssaMarker("ok")
   973  	deferBitsVar = ssaMarker("deferBits")
   974  )
   975  
   976  // startBlock sets the current block we're generating code in to b.
   977  func (s *state) startBlock(b *ssa.Block) {
   978  	if s.curBlock != nil {
   979  		s.Fatalf("starting block %v when block %v has not ended", b, s.curBlock)
   980  	}
   981  	s.curBlock = b
   982  	s.vars = map[ir.Node]*ssa.Value{}
   983  	for n := range s.fwdVars {
   984  		delete(s.fwdVars, n)
   985  	}
   986  }
   987  
   988  // endBlock marks the end of generating code for the current block.
   989  // Returns the (former) current block. Returns nil if there is no current
   990  // block, i.e. if no code flows to the current execution point.
   991  func (s *state) endBlock() *ssa.Block {
   992  	b := s.curBlock
   993  	if b == nil {
   994  		return nil
   995  	}
   996  	for len(s.defvars) <= int(b.ID) {
   997  		s.defvars = append(s.defvars, nil)
   998  	}
   999  	s.defvars[b.ID] = s.vars
  1000  	s.curBlock = nil
  1001  	s.vars = nil
  1002  	if b.LackingPos() {
  1003  		// Empty plain blocks get the line of their successor (handled after all blocks created),
  1004  		// except for increment blocks in For statements (handled in ssa conversion of OFOR),
  1005  		// and for blocks ending in GOTO/BREAK/CONTINUE.
  1006  		b.Pos = src.NoXPos
  1007  	} else {
  1008  		b.Pos = s.lastPos
  1009  	}
  1010  	return b
  1011  }
  1012  
  1013  // pushLine pushes a line number on the line number stack.
  1014  func (s *state) pushLine(line src.XPos) {
  1015  	if !line.IsKnown() {
  1016  		// the frontend may emit node with line number missing,
  1017  		// use the parent line number in this case.
  1018  		line = s.peekPos()
  1019  		if base.Flag.K != 0 {
  1020  			base.Warn("buildssa: unknown position (line 0)")
  1021  		}
  1022  	} else {
  1023  		s.lastPos = line
  1024  	}
  1025  
  1026  	s.line = append(s.line, line)
  1027  }
  1028  
  1029  // popLine pops the top of the line number stack.
  1030  func (s *state) popLine() {
  1031  	s.line = s.line[:len(s.line)-1]
  1032  }
  1033  
  1034  // peekPos peeks the top of the line number stack.
  1035  func (s *state) peekPos() src.XPos {
  1036  	return s.line[len(s.line)-1]
  1037  }
  1038  
  1039  // newValue0 adds a new value with no arguments to the current block.
  1040  func (s *state) newValue0(op ssa.Op, t *types.Type) *ssa.Value {
  1041  	return s.curBlock.NewValue0(s.peekPos(), op, t)
  1042  }
  1043  
  1044  // newValue0A adds a new value with no arguments and an aux value to the current block.
  1045  func (s *state) newValue0A(op ssa.Op, t *types.Type, aux ssa.Aux) *ssa.Value {
  1046  	return s.curBlock.NewValue0A(s.peekPos(), op, t, aux)
  1047  }
  1048  
  1049  // newValue0I adds a new value with no arguments and an auxint value to the current block.
  1050  func (s *state) newValue0I(op ssa.Op, t *types.Type, auxint int64) *ssa.Value {
  1051  	return s.curBlock.NewValue0I(s.peekPos(), op, t, auxint)
  1052  }
  1053  
  1054  // newValue1 adds a new value with one argument to the current block.
  1055  func (s *state) newValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1056  	return s.curBlock.NewValue1(s.peekPos(), op, t, arg)
  1057  }
  1058  
  1059  // newValue1A adds a new value with one argument and an aux value to the current block.
  1060  func (s *state) newValue1A(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value) *ssa.Value {
  1061  	return s.curBlock.NewValue1A(s.peekPos(), op, t, aux, arg)
  1062  }
  1063  
  1064  // newValue1Apos adds a new value with one argument and an aux value to the current block.
  1065  // isStmt determines whether the created values may be a statement or not
  1066  // (i.e., false means never, yes means maybe).
  1067  func (s *state) newValue1Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value, isStmt bool) *ssa.Value {
  1068  	if isStmt {
  1069  		return s.curBlock.NewValue1A(s.peekPos(), op, t, aux, arg)
  1070  	}
  1071  	return s.curBlock.NewValue1A(s.peekPos().WithNotStmt(), op, t, aux, arg)
  1072  }
  1073  
  1074  // newValue1I adds a new value with one argument and an auxint value to the current block.
  1075  func (s *state) newValue1I(op ssa.Op, t *types.Type, aux int64, arg *ssa.Value) *ssa.Value {
  1076  	return s.curBlock.NewValue1I(s.peekPos(), op, t, aux, arg)
  1077  }
  1078  
  1079  // newValue2 adds a new value with two arguments to the current block.
  1080  func (s *state) newValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1081  	return s.curBlock.NewValue2(s.peekPos(), op, t, arg0, arg1)
  1082  }
  1083  
  1084  // newValue2A adds a new value with two arguments and an aux value to the current block.
  1085  func (s *state) newValue2A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value) *ssa.Value {
  1086  	return s.curBlock.NewValue2A(s.peekPos(), op, t, aux, arg0, arg1)
  1087  }
  1088  
  1089  // newValue2Apos adds a new value with two arguments and an aux value to the current block.
  1090  // isStmt determines whether the created values may be a statement or not
  1091  // (i.e., false means never, yes means maybe).
  1092  func (s *state) newValue2Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value, isStmt bool) *ssa.Value {
  1093  	if isStmt {
  1094  		return s.curBlock.NewValue2A(s.peekPos(), op, t, aux, arg0, arg1)
  1095  	}
  1096  	return s.curBlock.NewValue2A(s.peekPos().WithNotStmt(), op, t, aux, arg0, arg1)
  1097  }
  1098  
  1099  // newValue2I adds a new value with two arguments and an auxint value to the current block.
  1100  func (s *state) newValue2I(op ssa.Op, t *types.Type, aux int64, arg0, arg1 *ssa.Value) *ssa.Value {
  1101  	return s.curBlock.NewValue2I(s.peekPos(), op, t, aux, arg0, arg1)
  1102  }
  1103  
  1104  // newValue3 adds a new value with three arguments to the current block.
  1105  func (s *state) newValue3(op ssa.Op, t *types.Type, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1106  	return s.curBlock.NewValue3(s.peekPos(), op, t, arg0, arg1, arg2)
  1107  }
  1108  
  1109  // newValue3I adds a new value with three arguments and an auxint value to the current block.
  1110  func (s *state) newValue3I(op ssa.Op, t *types.Type, aux int64, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1111  	return s.curBlock.NewValue3I(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1112  }
  1113  
  1114  // newValue3A adds a new value with three arguments and an aux value to the current block.
  1115  func (s *state) newValue3A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1116  	return s.curBlock.NewValue3A(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1117  }
  1118  
  1119  // newValue3Apos adds a new value with three arguments and an aux value to the current block.
  1120  // isStmt determines whether the created values may be a statement or not
  1121  // (i.e., false means never, yes means maybe).
  1122  func (s *state) newValue3Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2 *ssa.Value, isStmt bool) *ssa.Value {
  1123  	if isStmt {
  1124  		return s.curBlock.NewValue3A(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1125  	}
  1126  	return s.curBlock.NewValue3A(s.peekPos().WithNotStmt(), op, t, aux, arg0, arg1, arg2)
  1127  }
  1128  
  1129  // newValue4 adds a new value with four arguments to the current block.
  1130  func (s *state) newValue4(op ssa.Op, t *types.Type, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1131  	return s.curBlock.NewValue4(s.peekPos(), op, t, arg0, arg1, arg2, arg3)
  1132  }
  1133  
  1134  // newValue4 adds a new value with four arguments and an auxint value to the current block.
  1135  func (s *state) newValue4I(op ssa.Op, t *types.Type, aux int64, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1136  	return s.curBlock.NewValue4I(s.peekPos(), op, t, aux, arg0, arg1, arg2, arg3)
  1137  }
  1138  
  1139  func (s *state) entryBlock() *ssa.Block {
  1140  	b := s.f.Entry
  1141  	if base.Flag.N > 0 && s.curBlock != nil {
  1142  		// If optimizations are off, allocate in current block instead. Since with -N
  1143  		// we're not doing the CSE or tighten passes, putting lots of stuff in the
  1144  		// entry block leads to O(n^2) entries in the live value map during regalloc.
  1145  		// See issue 45897.
  1146  		b = s.curBlock
  1147  	}
  1148  	return b
  1149  }
  1150  
  1151  // entryNewValue0 adds a new value with no arguments to the entry block.
  1152  func (s *state) entryNewValue0(op ssa.Op, t *types.Type) *ssa.Value {
  1153  	return s.entryBlock().NewValue0(src.NoXPos, op, t)
  1154  }
  1155  
  1156  // entryNewValue0A adds a new value with no arguments and an aux value to the entry block.
  1157  func (s *state) entryNewValue0A(op ssa.Op, t *types.Type, aux ssa.Aux) *ssa.Value {
  1158  	return s.entryBlock().NewValue0A(src.NoXPos, op, t, aux)
  1159  }
  1160  
  1161  // entryNewValue1 adds a new value with one argument to the entry block.
  1162  func (s *state) entryNewValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1163  	return s.entryBlock().NewValue1(src.NoXPos, op, t, arg)
  1164  }
  1165  
  1166  // entryNewValue1 adds a new value with one argument and an auxint value to the entry block.
  1167  func (s *state) entryNewValue1I(op ssa.Op, t *types.Type, auxint int64, arg *ssa.Value) *ssa.Value {
  1168  	return s.entryBlock().NewValue1I(src.NoXPos, op, t, auxint, arg)
  1169  }
  1170  
  1171  // entryNewValue1A adds a new value with one argument and an aux value to the entry block.
  1172  func (s *state) entryNewValue1A(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value) *ssa.Value {
  1173  	return s.entryBlock().NewValue1A(src.NoXPos, op, t, aux, arg)
  1174  }
  1175  
  1176  // entryNewValue2 adds a new value with two arguments to the entry block.
  1177  func (s *state) entryNewValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1178  	return s.entryBlock().NewValue2(src.NoXPos, op, t, arg0, arg1)
  1179  }
  1180  
  1181  // entryNewValue2A adds a new value with two arguments and an aux value to the entry block.
  1182  func (s *state) entryNewValue2A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value) *ssa.Value {
  1183  	return s.entryBlock().NewValue2A(src.NoXPos, op, t, aux, arg0, arg1)
  1184  }
  1185  
  1186  // const* routines add a new const value to the entry block.
  1187  func (s *state) constSlice(t *types.Type) *ssa.Value {
  1188  	return s.f.ConstSlice(t)
  1189  }
  1190  func (s *state) constInterface(t *types.Type) *ssa.Value {
  1191  	return s.f.ConstInterface(t)
  1192  }
  1193  func (s *state) constNil(t *types.Type) *ssa.Value { return s.f.ConstNil(t) }
  1194  func (s *state) constEmptyString(t *types.Type) *ssa.Value {
  1195  	return s.f.ConstEmptyString(t)
  1196  }
  1197  func (s *state) constBool(c bool) *ssa.Value {
  1198  	return s.f.ConstBool(types.Types[types.TBOOL], c)
  1199  }
  1200  func (s *state) constInt8(t *types.Type, c int8) *ssa.Value {
  1201  	return s.f.ConstInt8(t, c)
  1202  }
  1203  func (s *state) constInt16(t *types.Type, c int16) *ssa.Value {
  1204  	return s.f.ConstInt16(t, c)
  1205  }
  1206  func (s *state) constInt32(t *types.Type, c int32) *ssa.Value {
  1207  	return s.f.ConstInt32(t, c)
  1208  }
  1209  func (s *state) constInt64(t *types.Type, c int64) *ssa.Value {
  1210  	return s.f.ConstInt64(t, c)
  1211  }
  1212  func (s *state) constFloat32(t *types.Type, c float64) *ssa.Value {
  1213  	return s.f.ConstFloat32(t, c)
  1214  }
  1215  func (s *state) constFloat64(t *types.Type, c float64) *ssa.Value {
  1216  	return s.f.ConstFloat64(t, c)
  1217  }
  1218  func (s *state) constInt(t *types.Type, c int64) *ssa.Value {
  1219  	if s.config.PtrSize == 8 {
  1220  		return s.constInt64(t, c)
  1221  	}
  1222  	if int64(int32(c)) != c {
  1223  		s.Fatalf("integer constant too big %d", c)
  1224  	}
  1225  	return s.constInt32(t, int32(c))
  1226  }
  1227  func (s *state) constOffPtrSP(t *types.Type, c int64) *ssa.Value {
  1228  	return s.f.ConstOffPtrSP(t, c, s.sp)
  1229  }
  1230  
  1231  // newValueOrSfCall* are wrappers around newValue*, which may create a call to a
  1232  // soft-float runtime function instead (when emitting soft-float code).
  1233  func (s *state) newValueOrSfCall1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1234  	if s.softFloat {
  1235  		if c, ok := s.sfcall(op, arg); ok {
  1236  			return c
  1237  		}
  1238  	}
  1239  	return s.newValue1(op, t, arg)
  1240  }
  1241  func (s *state) newValueOrSfCall2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1242  	if s.softFloat {
  1243  		if c, ok := s.sfcall(op, arg0, arg1); ok {
  1244  			return c
  1245  		}
  1246  	}
  1247  	return s.newValue2(op, t, arg0, arg1)
  1248  }
  1249  
  1250  type instrumentKind uint8
  1251  
  1252  const (
  1253  	instrumentRead = iota
  1254  	instrumentWrite
  1255  	instrumentMove
  1256  )
  1257  
  1258  func (s *state) instrument(t *types.Type, addr *ssa.Value, kind instrumentKind) {
  1259  	s.instrument2(t, addr, nil, kind)
  1260  }
  1261  
  1262  // instrumentFields instruments a read/write operation on addr.
  1263  // If it is instrumenting for MSAN or ASAN and t is a struct type, it instruments
  1264  // operation for each field, instead of for the whole struct.
  1265  func (s *state) instrumentFields(t *types.Type, addr *ssa.Value, kind instrumentKind) {
  1266  	if !(base.Flag.MSan || base.Flag.ASan) || !t.IsStruct() {
  1267  		s.instrument(t, addr, kind)
  1268  		return
  1269  	}
  1270  	for _, f := range t.Fields().Slice() {
  1271  		if f.Sym.IsBlank() {
  1272  			continue
  1273  		}
  1274  		offptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(f.Type), f.Offset, addr)
  1275  		s.instrumentFields(f.Type, offptr, kind)
  1276  	}
  1277  }
  1278  
  1279  func (s *state) instrumentMove(t *types.Type, dst, src *ssa.Value) {
  1280  	if base.Flag.MSan {
  1281  		s.instrument2(t, dst, src, instrumentMove)
  1282  	} else {
  1283  		s.instrument(t, src, instrumentRead)
  1284  		s.instrument(t, dst, instrumentWrite)
  1285  	}
  1286  }
  1287  
  1288  func (s *state) instrument2(t *types.Type, addr, addr2 *ssa.Value, kind instrumentKind) {
  1289  	if !s.curfn.InstrumentBody() {
  1290  		return
  1291  	}
  1292  
  1293  	w := t.Size()
  1294  	if w == 0 {
  1295  		return // can't race on zero-sized things
  1296  	}
  1297  
  1298  	if ssa.IsSanitizerSafeAddr(addr) {
  1299  		return
  1300  	}
  1301  
  1302  	var fn *obj.LSym
  1303  	needWidth := false
  1304  
  1305  	if addr2 != nil && kind != instrumentMove {
  1306  		panic("instrument2: non-nil addr2 for non-move instrumentation")
  1307  	}
  1308  
  1309  	if base.Flag.MSan {
  1310  		switch kind {
  1311  		case instrumentRead:
  1312  			fn = ir.Syms.Msanread
  1313  		case instrumentWrite:
  1314  			fn = ir.Syms.Msanwrite
  1315  		case instrumentMove:
  1316  			fn = ir.Syms.Msanmove
  1317  		default:
  1318  			panic("unreachable")
  1319  		}
  1320  		needWidth = true
  1321  	} else if base.Flag.Race && t.NumComponents(types.CountBlankFields) > 1 {
  1322  		// for composite objects we have to write every address
  1323  		// because a write might happen to any subobject.
  1324  		// composites with only one element don't have subobjects, though.
  1325  		switch kind {
  1326  		case instrumentRead:
  1327  			fn = ir.Syms.Racereadrange
  1328  		case instrumentWrite:
  1329  			fn = ir.Syms.Racewriterange
  1330  		default:
  1331  			panic("unreachable")
  1332  		}
  1333  		needWidth = true
  1334  	} else if base.Flag.Race {
  1335  		// for non-composite objects we can write just the start
  1336  		// address, as any write must write the first byte.
  1337  		switch kind {
  1338  		case instrumentRead:
  1339  			fn = ir.Syms.Raceread
  1340  		case instrumentWrite:
  1341  			fn = ir.Syms.Racewrite
  1342  		default:
  1343  			panic("unreachable")
  1344  		}
  1345  	} else if base.Flag.ASan {
  1346  		switch kind {
  1347  		case instrumentRead:
  1348  			fn = ir.Syms.Asanread
  1349  		case instrumentWrite:
  1350  			fn = ir.Syms.Asanwrite
  1351  		default:
  1352  			panic("unreachable")
  1353  		}
  1354  		needWidth = true
  1355  	} else {
  1356  		panic("unreachable")
  1357  	}
  1358  
  1359  	args := []*ssa.Value{addr}
  1360  	if addr2 != nil {
  1361  		args = append(args, addr2)
  1362  	}
  1363  	if needWidth {
  1364  		args = append(args, s.constInt(types.Types[types.TUINTPTR], w))
  1365  	}
  1366  	s.rtcall(fn, true, nil, args...)
  1367  }
  1368  
  1369  func (s *state) load(t *types.Type, src *ssa.Value) *ssa.Value {
  1370  	s.instrumentFields(t, src, instrumentRead)
  1371  	return s.rawLoad(t, src)
  1372  }
  1373  
  1374  func (s *state) rawLoad(t *types.Type, src *ssa.Value) *ssa.Value {
  1375  	return s.newValue2(ssa.OpLoad, t, src, s.mem())
  1376  }
  1377  
  1378  func (s *state) store(t *types.Type, dst, val *ssa.Value) {
  1379  	s.vars[memVar] = s.newValue3A(ssa.OpStore, types.TypeMem, t, dst, val, s.mem())
  1380  }
  1381  
  1382  func (s *state) zero(t *types.Type, dst *ssa.Value) {
  1383  	s.instrument(t, dst, instrumentWrite)
  1384  	store := s.newValue2I(ssa.OpZero, types.TypeMem, t.Size(), dst, s.mem())
  1385  	store.Aux = t
  1386  	s.vars[memVar] = store
  1387  }
  1388  
  1389  func (s *state) move(t *types.Type, dst, src *ssa.Value) {
  1390  	s.instrumentMove(t, dst, src)
  1391  	store := s.newValue3I(ssa.OpMove, types.TypeMem, t.Size(), dst, src, s.mem())
  1392  	store.Aux = t
  1393  	s.vars[memVar] = store
  1394  }
  1395  
  1396  // stmtList converts the statement list n to SSA and adds it to s.
  1397  func (s *state) stmtList(l ir.Nodes) {
  1398  	for _, n := range l {
  1399  		s.stmt(n)
  1400  	}
  1401  }
  1402  
  1403  // stmt converts the statement n to SSA and adds it to s.
  1404  func (s *state) stmt(n ir.Node) {
  1405  	if !(n.Op() == ir.OVARKILL || n.Op() == ir.OVARLIVE || n.Op() == ir.OVARDEF) {
  1406  		// OVARKILL, OVARLIVE, and OVARDEF are invisible to the programmer, so we don't use their line numbers to avoid confusion in debugging.
  1407  		s.pushLine(n.Pos())
  1408  		defer s.popLine()
  1409  	}
  1410  
  1411  	// If s.curBlock is nil, and n isn't a label (which might have an associated goto somewhere),
  1412  	// then this code is dead. Stop here.
  1413  	if s.curBlock == nil && n.Op() != ir.OLABEL {
  1414  		return
  1415  	}
  1416  
  1417  	s.stmtList(n.Init())
  1418  	switch n.Op() {
  1419  
  1420  	case ir.OBLOCK:
  1421  		n := n.(*ir.BlockStmt)
  1422  		s.stmtList(n.List)
  1423  
  1424  	// No-ops
  1425  	case ir.ODCLCONST, ir.ODCLTYPE, ir.OFALL:
  1426  
  1427  	// Expression statements
  1428  	case ir.OCALLFUNC:
  1429  		n := n.(*ir.CallExpr)
  1430  		if ir.IsIntrinsicCall(n) {
  1431  			s.intrinsicCall(n)
  1432  			return
  1433  		}
  1434  		fallthrough
  1435  
  1436  	case ir.OCALLINTER:
  1437  		n := n.(*ir.CallExpr)
  1438  		s.callResult(n, callNormal)
  1439  		if n.Op() == ir.OCALLFUNC && n.X.Op() == ir.ONAME && n.X.(*ir.Name).Class == ir.PFUNC {
  1440  			if fn := n.X.Sym().Name; base.Flag.CompilingRuntime && fn == "throw" ||
  1441  				n.X.Sym().Pkg == ir.Pkgs.Runtime && (fn == "throwinit" || fn == "gopanic" || fn == "panicwrap" || fn == "block" || fn == "panicmakeslicelen" || fn == "panicmakeslicecap") {
  1442  				m := s.mem()
  1443  				b := s.endBlock()
  1444  				b.Kind = ssa.BlockExit
  1445  				b.SetControl(m)
  1446  				// TODO: never rewrite OPANIC to OCALLFUNC in the
  1447  				// first place. Need to wait until all backends
  1448  				// go through SSA.
  1449  			}
  1450  		}
  1451  	case ir.ODEFER:
  1452  		n := n.(*ir.GoDeferStmt)
  1453  		if base.Debug.Defer > 0 {
  1454  			var defertype string
  1455  			if s.hasOpenDefers {
  1456  				defertype = "open-coded"
  1457  			} else if n.Esc() == ir.EscNever {
  1458  				defertype = "stack-allocated"
  1459  			} else {
  1460  				defertype = "heap-allocated"
  1461  			}
  1462  			base.WarnfAt(n.Pos(), "%s defer", defertype)
  1463  		}
  1464  		if s.hasOpenDefers {
  1465  			s.openDeferRecord(n.Call.(*ir.CallExpr))
  1466  		} else {
  1467  			d := callDefer
  1468  			if n.Esc() == ir.EscNever {
  1469  				d = callDeferStack
  1470  			}
  1471  			s.callResult(n.Call.(*ir.CallExpr), d)
  1472  		}
  1473  	case ir.OGO:
  1474  		n := n.(*ir.GoDeferStmt)
  1475  		s.callResult(n.Call.(*ir.CallExpr), callGo)
  1476  
  1477  	case ir.OAS2DOTTYPE:
  1478  		n := n.(*ir.AssignListStmt)
  1479  		var res, resok *ssa.Value
  1480  		if n.Rhs[0].Op() == ir.ODOTTYPE2 {
  1481  			res, resok = s.dottype(n.Rhs[0].(*ir.TypeAssertExpr), true)
  1482  		} else {
  1483  			res, resok = s.dynamicDottype(n.Rhs[0].(*ir.DynamicTypeAssertExpr), true)
  1484  		}
  1485  		deref := false
  1486  		if !TypeOK(n.Rhs[0].Type()) {
  1487  			if res.Op != ssa.OpLoad {
  1488  				s.Fatalf("dottype of non-load")
  1489  			}
  1490  			mem := s.mem()
  1491  			if mem.Op == ssa.OpVarKill {
  1492  				mem = mem.Args[0]
  1493  			}
  1494  			if res.Args[1] != mem {
  1495  				s.Fatalf("memory no longer live from 2-result dottype load")
  1496  			}
  1497  			deref = true
  1498  			res = res.Args[0]
  1499  		}
  1500  		s.assign(n.Lhs[0], res, deref, 0)
  1501  		s.assign(n.Lhs[1], resok, false, 0)
  1502  		return
  1503  
  1504  	case ir.OAS2FUNC:
  1505  		// We come here only when it is an intrinsic call returning two values.
  1506  		n := n.(*ir.AssignListStmt)
  1507  		call := n.Rhs[0].(*ir.CallExpr)
  1508  		if !ir.IsIntrinsicCall(call) {
  1509  			s.Fatalf("non-intrinsic AS2FUNC not expanded %v", call)
  1510  		}
  1511  		v := s.intrinsicCall(call)
  1512  		v1 := s.newValue1(ssa.OpSelect0, n.Lhs[0].Type(), v)
  1513  		v2 := s.newValue1(ssa.OpSelect1, n.Lhs[1].Type(), v)
  1514  		s.assign(n.Lhs[0], v1, false, 0)
  1515  		s.assign(n.Lhs[1], v2, false, 0)
  1516  		return
  1517  
  1518  	case ir.ODCL:
  1519  		n := n.(*ir.Decl)
  1520  		if v := n.X; v.Esc() == ir.EscHeap {
  1521  			s.newHeapaddr(v)
  1522  		}
  1523  
  1524  	case ir.OLABEL:
  1525  		n := n.(*ir.LabelStmt)
  1526  		sym := n.Label
  1527  		lab := s.label(sym)
  1528  
  1529  		// The label might already have a target block via a goto.
  1530  		if lab.target == nil {
  1531  			lab.target = s.f.NewBlock(ssa.BlockPlain)
  1532  		}
  1533  
  1534  		// Go to that label.
  1535  		// (We pretend "label:" is preceded by "goto label", unless the predecessor is unreachable.)
  1536  		if s.curBlock != nil {
  1537  			b := s.endBlock()
  1538  			b.AddEdgeTo(lab.target)
  1539  		}
  1540  		s.startBlock(lab.target)
  1541  
  1542  	case ir.OGOTO:
  1543  		n := n.(*ir.BranchStmt)
  1544  		sym := n.Label
  1545  
  1546  		lab := s.label(sym)
  1547  		if lab.target == nil {
  1548  			lab.target = s.f.NewBlock(ssa.BlockPlain)
  1549  		}
  1550  
  1551  		b := s.endBlock()
  1552  		b.Pos = s.lastPos.WithIsStmt() // Do this even if b is an empty block.
  1553  		b.AddEdgeTo(lab.target)
  1554  
  1555  	case ir.OAS:
  1556  		n := n.(*ir.AssignStmt)
  1557  		if n.X == n.Y && n.X.Op() == ir.ONAME {
  1558  			// An x=x assignment. No point in doing anything
  1559  			// here. In addition, skipping this assignment
  1560  			// prevents generating:
  1561  			//   VARDEF x
  1562  			//   COPY x -> x
  1563  			// which is bad because x is incorrectly considered
  1564  			// dead before the vardef. See issue #14904.
  1565  			return
  1566  		}
  1567  
  1568  		// Evaluate RHS.
  1569  		rhs := n.Y
  1570  		if rhs != nil {
  1571  			switch rhs.Op() {
  1572  			case ir.OSTRUCTLIT, ir.OARRAYLIT, ir.OSLICELIT:
  1573  				// All literals with nonzero fields have already been
  1574  				// rewritten during walk. Any that remain are just T{}
  1575  				// or equivalents. Use the zero value.
  1576  				if !ir.IsZero(rhs) {
  1577  					s.Fatalf("literal with nonzero value in SSA: %v", rhs)
  1578  				}
  1579  				rhs = nil
  1580  			case ir.OAPPEND:
  1581  				rhs := rhs.(*ir.CallExpr)
  1582  				// Check whether we're writing the result of an append back to the same slice.
  1583  				// If so, we handle it specially to avoid write barriers on the fast
  1584  				// (non-growth) path.
  1585  				if !ir.SameSafeExpr(n.X, rhs.Args[0]) || base.Flag.N != 0 {
  1586  					break
  1587  				}
  1588  				// If the slice can be SSA'd, it'll be on the stack,
  1589  				// so there will be no write barriers,
  1590  				// so there's no need to attempt to prevent them.
  1591  				if s.canSSA(n.X) {
  1592  					if base.Debug.Append > 0 { // replicating old diagnostic message
  1593  						base.WarnfAt(n.Pos(), "append: len-only update (in local slice)")
  1594  					}
  1595  					break
  1596  				}
  1597  				if base.Debug.Append > 0 {
  1598  					base.WarnfAt(n.Pos(), "append: len-only update")
  1599  				}
  1600  				s.append(rhs, true)
  1601  				return
  1602  			}
  1603  		}
  1604  
  1605  		if ir.IsBlank(n.X) {
  1606  			// _ = rhs
  1607  			// Just evaluate rhs for side-effects.
  1608  			if rhs != nil {
  1609  				s.expr(rhs)
  1610  			}
  1611  			return
  1612  		}
  1613  
  1614  		var t *types.Type
  1615  		if n.Y != nil {
  1616  			t = n.Y.Type()
  1617  		} else {
  1618  			t = n.X.Type()
  1619  		}
  1620  
  1621  		var r *ssa.Value
  1622  		deref := !TypeOK(t)
  1623  		if deref {
  1624  			if rhs == nil {
  1625  				r = nil // Signal assign to use OpZero.
  1626  			} else {
  1627  				r = s.addr(rhs)
  1628  			}
  1629  		} else {
  1630  			if rhs == nil {
  1631  				r = s.zeroVal(t)
  1632  			} else {
  1633  				r = s.expr(rhs)
  1634  			}
  1635  		}
  1636  
  1637  		var skip skipMask
  1638  		if rhs != nil && (rhs.Op() == ir.OSLICE || rhs.Op() == ir.OSLICE3 || rhs.Op() == ir.OSLICESTR) && ir.SameSafeExpr(rhs.(*ir.SliceExpr).X, n.X) {
  1639  			// We're assigning a slicing operation back to its source.
  1640  			// Don't write back fields we aren't changing. See issue #14855.
  1641  			rhs := rhs.(*ir.SliceExpr)
  1642  			i, j, k := rhs.Low, rhs.High, rhs.Max
  1643  			if i != nil && (i.Op() == ir.OLITERAL && i.Val().Kind() == constant.Int && ir.Int64Val(i) == 0) {
  1644  				// [0:...] is the same as [:...]
  1645  				i = nil
  1646  			}
  1647  			// TODO: detect defaults for len/cap also.
  1648  			// Currently doesn't really work because (*p)[:len(*p)] appears here as:
  1649  			//    tmp = len(*p)
  1650  			//    (*p)[:tmp]
  1651  			//if j != nil && (j.Op == OLEN && SameSafeExpr(j.Left, n.Left)) {
  1652  			//      j = nil
  1653  			//}
  1654  			//if k != nil && (k.Op == OCAP && SameSafeExpr(k.Left, n.Left)) {
  1655  			//      k = nil
  1656  			//}
  1657  			if i == nil {
  1658  				skip |= skipPtr
  1659  				if j == nil {
  1660  					skip |= skipLen
  1661  				}
  1662  				if k == nil {
  1663  					skip |= skipCap
  1664  				}
  1665  			}
  1666  		}
  1667  
  1668  		s.assign(n.X, r, deref, skip)
  1669  
  1670  	case ir.OIF:
  1671  		n := n.(*ir.IfStmt)
  1672  		if ir.IsConst(n.Cond, constant.Bool) {
  1673  			s.stmtList(n.Cond.Init())
  1674  			if ir.BoolVal(n.Cond) {
  1675  				s.stmtList(n.Body)
  1676  			} else {
  1677  				s.stmtList(n.Else)
  1678  			}
  1679  			break
  1680  		}
  1681  
  1682  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  1683  		var likely int8
  1684  		if n.Likely {
  1685  			likely = 1
  1686  		}
  1687  		var bThen *ssa.Block
  1688  		if len(n.Body) != 0 {
  1689  			bThen = s.f.NewBlock(ssa.BlockPlain)
  1690  		} else {
  1691  			bThen = bEnd
  1692  		}
  1693  		var bElse *ssa.Block
  1694  		if len(n.Else) != 0 {
  1695  			bElse = s.f.NewBlock(ssa.BlockPlain)
  1696  		} else {
  1697  			bElse = bEnd
  1698  		}
  1699  		s.condBranch(n.Cond, bThen, bElse, likely)
  1700  
  1701  		if len(n.Body) != 0 {
  1702  			s.startBlock(bThen)
  1703  			s.stmtList(n.Body)
  1704  			if b := s.endBlock(); b != nil {
  1705  				b.AddEdgeTo(bEnd)
  1706  			}
  1707  		}
  1708  		if len(n.Else) != 0 {
  1709  			s.startBlock(bElse)
  1710  			s.stmtList(n.Else)
  1711  			if b := s.endBlock(); b != nil {
  1712  				b.AddEdgeTo(bEnd)
  1713  			}
  1714  		}
  1715  		s.startBlock(bEnd)
  1716  
  1717  	case ir.ORETURN:
  1718  		n := n.(*ir.ReturnStmt)
  1719  		s.stmtList(n.Results)
  1720  		b := s.exit()
  1721  		b.Pos = s.lastPos.WithIsStmt()
  1722  
  1723  	case ir.OTAILCALL:
  1724  		n := n.(*ir.TailCallStmt)
  1725  		s.callResult(n.Call, callTail)
  1726  		call := s.mem()
  1727  		b := s.endBlock()
  1728  		b.Kind = ssa.BlockRetJmp // could use BlockExit. BlockRetJmp is mostly for clarity.
  1729  		b.SetControl(call)
  1730  
  1731  	case ir.OCONTINUE, ir.OBREAK:
  1732  		n := n.(*ir.BranchStmt)
  1733  		var to *ssa.Block
  1734  		if n.Label == nil {
  1735  			// plain break/continue
  1736  			switch n.Op() {
  1737  			case ir.OCONTINUE:
  1738  				to = s.continueTo
  1739  			case ir.OBREAK:
  1740  				to = s.breakTo
  1741  			}
  1742  		} else {
  1743  			// labeled break/continue; look up the target
  1744  			sym := n.Label
  1745  			lab := s.label(sym)
  1746  			switch n.Op() {
  1747  			case ir.OCONTINUE:
  1748  				to = lab.continueTarget
  1749  			case ir.OBREAK:
  1750  				to = lab.breakTarget
  1751  			}
  1752  		}
  1753  
  1754  		b := s.endBlock()
  1755  		b.Pos = s.lastPos.WithIsStmt() // Do this even if b is an empty block.
  1756  		b.AddEdgeTo(to)
  1757  
  1758  	case ir.OFOR, ir.OFORUNTIL:
  1759  		// OFOR: for Ninit; Left; Right { Nbody }
  1760  		// cond (Left); body (Nbody); incr (Right)
  1761  		//
  1762  		// OFORUNTIL: for Ninit; Left; Right; List { Nbody }
  1763  		// => body: { Nbody }; incr: Right; if Left { lateincr: List; goto body }; end:
  1764  		n := n.(*ir.ForStmt)
  1765  		bCond := s.f.NewBlock(ssa.BlockPlain)
  1766  		bBody := s.f.NewBlock(ssa.BlockPlain)
  1767  		bIncr := s.f.NewBlock(ssa.BlockPlain)
  1768  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  1769  
  1770  		// ensure empty for loops have correct position; issue #30167
  1771  		bBody.Pos = n.Pos()
  1772  
  1773  		// first, jump to condition test (OFOR) or body (OFORUNTIL)
  1774  		b := s.endBlock()
  1775  		if n.Op() == ir.OFOR {
  1776  			b.AddEdgeTo(bCond)
  1777  			// generate code to test condition
  1778  			s.startBlock(bCond)
  1779  			if n.Cond != nil {
  1780  				s.condBranch(n.Cond, bBody, bEnd, 1)
  1781  			} else {
  1782  				b := s.endBlock()
  1783  				b.Kind = ssa.BlockPlain
  1784  				b.AddEdgeTo(bBody)
  1785  			}
  1786  
  1787  		} else {
  1788  			b.AddEdgeTo(bBody)
  1789  		}
  1790  
  1791  		// set up for continue/break in body
  1792  		prevContinue := s.continueTo
  1793  		prevBreak := s.breakTo
  1794  		s.continueTo = bIncr
  1795  		s.breakTo = bEnd
  1796  		var lab *ssaLabel
  1797  		if sym := n.Label; sym != nil {
  1798  			// labeled for loop
  1799  			lab = s.label(sym)
  1800  			lab.continueTarget = bIncr
  1801  			lab.breakTarget = bEnd
  1802  		}
  1803  
  1804  		// generate body
  1805  		s.startBlock(bBody)
  1806  		s.stmtList(n.Body)
  1807  
  1808  		// tear down continue/break
  1809  		s.continueTo = prevContinue
  1810  		s.breakTo = prevBreak
  1811  		if lab != nil {
  1812  			lab.continueTarget = nil
  1813  			lab.breakTarget = nil
  1814  		}
  1815  
  1816  		// done with body, goto incr
  1817  		if b := s.endBlock(); b != nil {
  1818  			b.AddEdgeTo(bIncr)
  1819  		}
  1820  
  1821  		// generate incr (and, for OFORUNTIL, condition)
  1822  		s.startBlock(bIncr)
  1823  		if n.Post != nil {
  1824  			s.stmt(n.Post)
  1825  		}
  1826  		if n.Op() == ir.OFOR {
  1827  			if b := s.endBlock(); b != nil {
  1828  				b.AddEdgeTo(bCond)
  1829  				// It can happen that bIncr ends in a block containing only VARKILL,
  1830  				// and that muddles the debugging experience.
  1831  				if b.Pos == src.NoXPos {
  1832  					b.Pos = bCond.Pos
  1833  				}
  1834  			}
  1835  		} else {
  1836  			// bCond is unused in OFORUNTIL, so repurpose it.
  1837  			bLateIncr := bCond
  1838  			// test condition
  1839  			s.condBranch(n.Cond, bLateIncr, bEnd, 1)
  1840  			// generate late increment
  1841  			s.startBlock(bLateIncr)
  1842  			s.stmtList(n.Late)
  1843  			s.endBlock().AddEdgeTo(bBody)
  1844  		}
  1845  
  1846  		s.startBlock(bEnd)
  1847  
  1848  	case ir.OSWITCH, ir.OSELECT:
  1849  		// These have been mostly rewritten by the front end into their Nbody fields.
  1850  		// Our main task is to correctly hook up any break statements.
  1851  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  1852  
  1853  		prevBreak := s.breakTo
  1854  		s.breakTo = bEnd
  1855  		var sym *types.Sym
  1856  		var body ir.Nodes
  1857  		if n.Op() == ir.OSWITCH {
  1858  			n := n.(*ir.SwitchStmt)
  1859  			sym = n.Label
  1860  			body = n.Compiled
  1861  		} else {
  1862  			n := n.(*ir.SelectStmt)
  1863  			sym = n.Label
  1864  			body = n.Compiled
  1865  		}
  1866  
  1867  		var lab *ssaLabel
  1868  		if sym != nil {
  1869  			// labeled
  1870  			lab = s.label(sym)
  1871  			lab.breakTarget = bEnd
  1872  		}
  1873  
  1874  		// generate body code
  1875  		s.stmtList(body)
  1876  
  1877  		s.breakTo = prevBreak
  1878  		if lab != nil {
  1879  			lab.breakTarget = nil
  1880  		}
  1881  
  1882  		// walk adds explicit OBREAK nodes to the end of all reachable code paths.
  1883  		// If we still have a current block here, then mark it unreachable.
  1884  		if s.curBlock != nil {
  1885  			m := s.mem()
  1886  			b := s.endBlock()
  1887  			b.Kind = ssa.BlockExit
  1888  			b.SetControl(m)
  1889  		}
  1890  		s.startBlock(bEnd)
  1891  
  1892  	case ir.OVARDEF:
  1893  		n := n.(*ir.UnaryExpr)
  1894  		if !s.canSSA(n.X) {
  1895  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, n.X.(*ir.Name), s.mem(), false)
  1896  		}
  1897  	case ir.OVARKILL:
  1898  		// Insert a varkill op to record that a variable is no longer live.
  1899  		// We only care about liveness info at call sites, so putting the
  1900  		// varkill in the store chain is enough to keep it correctly ordered
  1901  		// with respect to call ops.
  1902  		n := n.(*ir.UnaryExpr)
  1903  		if !s.canSSA(n.X) {
  1904  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarKill, types.TypeMem, n.X.(*ir.Name), s.mem(), false)
  1905  		}
  1906  
  1907  	case ir.OVARLIVE:
  1908  		// Insert a varlive op to record that a variable is still live.
  1909  		n := n.(*ir.UnaryExpr)
  1910  		v := n.X.(*ir.Name)
  1911  		if !v.Addrtaken() {
  1912  			s.Fatalf("VARLIVE variable %v must have Addrtaken set", v)
  1913  		}
  1914  		switch v.Class {
  1915  		case ir.PAUTO, ir.PPARAM, ir.PPARAMOUT:
  1916  		default:
  1917  			s.Fatalf("VARLIVE variable %v must be Auto or Arg", v)
  1918  		}
  1919  		s.vars[memVar] = s.newValue1A(ssa.OpVarLive, types.TypeMem, v, s.mem())
  1920  
  1921  	case ir.OCHECKNIL:
  1922  		n := n.(*ir.UnaryExpr)
  1923  		p := s.expr(n.X)
  1924  		s.nilCheck(p)
  1925  
  1926  	case ir.OINLMARK:
  1927  		n := n.(*ir.InlineMarkStmt)
  1928  		s.newValue1I(ssa.OpInlMark, types.TypeVoid, n.Index, s.mem())
  1929  
  1930  	default:
  1931  		s.Fatalf("unhandled stmt %v", n.Op())
  1932  	}
  1933  }
  1934  
  1935  // If true, share as many open-coded defer exits as possible (with the downside of
  1936  // worse line-number information)
  1937  const shareDeferExits = false
  1938  
  1939  // exit processes any code that needs to be generated just before returning.
  1940  // It returns a BlockRet block that ends the control flow. Its control value
  1941  // will be set to the final memory state.
  1942  func (s *state) exit() *ssa.Block {
  1943  	if s.hasdefer {
  1944  		if s.hasOpenDefers {
  1945  			if shareDeferExits && s.lastDeferExit != nil && len(s.openDefers) == s.lastDeferCount {
  1946  				if s.curBlock.Kind != ssa.BlockPlain {
  1947  					panic("Block for an exit should be BlockPlain")
  1948  				}
  1949  				s.curBlock.AddEdgeTo(s.lastDeferExit)
  1950  				s.endBlock()
  1951  				return s.lastDeferFinalBlock
  1952  			}
  1953  			s.openDeferExit()
  1954  		} else {
  1955  			s.rtcall(ir.Syms.Deferreturn, true, nil)
  1956  		}
  1957  	}
  1958  
  1959  	var b *ssa.Block
  1960  	var m *ssa.Value
  1961  	// Do actual return.
  1962  	// These currently turn into self-copies (in many cases).
  1963  	resultFields := s.curfn.Type().Results().FieldSlice()
  1964  	results := make([]*ssa.Value, len(resultFields)+1, len(resultFields)+1)
  1965  	m = s.newValue0(ssa.OpMakeResult, s.f.OwnAux.LateExpansionResultType())
  1966  	// Store SSAable and heap-escaped PPARAMOUT variables back to stack locations.
  1967  	for i, f := range resultFields {
  1968  		n := f.Nname.(*ir.Name)
  1969  		if s.canSSA(n) { // result is in some SSA variable
  1970  			if !n.IsOutputParamInRegisters() {
  1971  				// We are about to store to the result slot.
  1972  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
  1973  			}
  1974  			results[i] = s.variable(n, n.Type())
  1975  		} else if !n.OnStack() { // result is actually heap allocated
  1976  			// We are about to copy the in-heap result to the result slot.
  1977  			s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
  1978  			ha := s.expr(n.Heapaddr)
  1979  			s.instrumentFields(n.Type(), ha, instrumentRead)
  1980  			results[i] = s.newValue2(ssa.OpDereference, n.Type(), ha, s.mem())
  1981  		} else { // result is not SSA-able; not escaped, so not on heap, but too large for SSA.
  1982  			// Before register ABI this ought to be a self-move, home=dest,
  1983  			// With register ABI, it's still a self-move if parameter is on stack (i.e., too big or overflowed)
  1984  			// No VarDef, as the result slot is already holding live value.
  1985  			results[i] = s.newValue2(ssa.OpDereference, n.Type(), s.addr(n), s.mem())
  1986  		}
  1987  	}
  1988  
  1989  	// Run exit code. Today, this is just racefuncexit, in -race mode.
  1990  	// TODO(register args) this seems risky here with a register-ABI, but not clear it is right to do it earlier either.
  1991  	// Spills in register allocation might just fix it.
  1992  	s.stmtList(s.curfn.Exit)
  1993  
  1994  	results[len(results)-1] = s.mem()
  1995  	m.AddArgs(results...)
  1996  
  1997  	b = s.endBlock()
  1998  	b.Kind = ssa.BlockRet
  1999  	b.SetControl(m)
  2000  	if s.hasdefer && s.hasOpenDefers {
  2001  		s.lastDeferFinalBlock = b
  2002  	}
  2003  	return b
  2004  }
  2005  
  2006  type opAndType struct {
  2007  	op    ir.Op
  2008  	etype types.Kind
  2009  }
  2010  
  2011  var opToSSA = map[opAndType]ssa.Op{
  2012  	opAndType{ir.OADD, types.TINT8}:    ssa.OpAdd8,
  2013  	opAndType{ir.OADD, types.TUINT8}:   ssa.OpAdd8,
  2014  	opAndType{ir.OADD, types.TINT16}:   ssa.OpAdd16,
  2015  	opAndType{ir.OADD, types.TUINT16}:  ssa.OpAdd16,
  2016  	opAndType{ir.OADD, types.TINT32}:   ssa.OpAdd32,
  2017  	opAndType{ir.OADD, types.TUINT32}:  ssa.OpAdd32,
  2018  	opAndType{ir.OADD, types.TINT64}:   ssa.OpAdd64,
  2019  	opAndType{ir.OADD, types.TUINT64}:  ssa.OpAdd64,
  2020  	opAndType{ir.OADD, types.TFLOAT32}: ssa.OpAdd32F,
  2021  	opAndType{ir.OADD, types.TFLOAT64}: ssa.OpAdd64F,
  2022  
  2023  	opAndType{ir.OSUB, types.TINT8}:    ssa.OpSub8,
  2024  	opAndType{ir.OSUB, types.TUINT8}:   ssa.OpSub8,
  2025  	opAndType{ir.OSUB, types.TINT16}:   ssa.OpSub16,
  2026  	opAndType{ir.OSUB, types.TUINT16}:  ssa.OpSub16,
  2027  	opAndType{ir.OSUB, types.TINT32}:   ssa.OpSub32,
  2028  	opAndType{ir.OSUB, types.TUINT32}:  ssa.OpSub32,
  2029  	opAndType{ir.OSUB, types.TINT64}:   ssa.OpSub64,
  2030  	opAndType{ir.OSUB, types.TUINT64}:  ssa.OpSub64,
  2031  	opAndType{ir.OSUB, types.TFLOAT32}: ssa.OpSub32F,
  2032  	opAndType{ir.OSUB, types.TFLOAT64}: ssa.OpSub64F,
  2033  
  2034  	opAndType{ir.ONOT, types.TBOOL}: ssa.OpNot,
  2035  
  2036  	opAndType{ir.ONEG, types.TINT8}:    ssa.OpNeg8,
  2037  	opAndType{ir.ONEG, types.TUINT8}:   ssa.OpNeg8,
  2038  	opAndType{ir.ONEG, types.TINT16}:   ssa.OpNeg16,
  2039  	opAndType{ir.ONEG, types.TUINT16}:  ssa.OpNeg16,
  2040  	opAndType{ir.ONEG, types.TINT32}:   ssa.OpNeg32,
  2041  	opAndType{ir.ONEG, types.TUINT32}:  ssa.OpNeg32,
  2042  	opAndType{ir.ONEG, types.TINT64}:   ssa.OpNeg64,
  2043  	opAndType{ir.ONEG, types.TUINT64}:  ssa.OpNeg64,
  2044  	opAndType{ir.ONEG, types.TFLOAT32}: ssa.OpNeg32F,
  2045  	opAndType{ir.ONEG, types.TFLOAT64}: ssa.OpNeg64F,
  2046  
  2047  	opAndType{ir.OBITNOT, types.TINT8}:   ssa.OpCom8,
  2048  	opAndType{ir.OBITNOT, types.TUINT8}:  ssa.OpCom8,
  2049  	opAndType{ir.OBITNOT, types.TINT16}:  ssa.OpCom16,
  2050  	opAndType{ir.OBITNOT, types.TUINT16}: ssa.OpCom16,
  2051  	opAndType{ir.OBITNOT, types.TINT32}:  ssa.OpCom32,
  2052  	opAndType{ir.OBITNOT, types.TUINT32}: ssa.OpCom32,
  2053  	opAndType{ir.OBITNOT, types.TINT64}:  ssa.OpCom64,
  2054  	opAndType{ir.OBITNOT, types.TUINT64}: ssa.OpCom64,
  2055  
  2056  	opAndType{ir.OIMAG, types.TCOMPLEX64}:  ssa.OpComplexImag,
  2057  	opAndType{ir.OIMAG, types.TCOMPLEX128}: ssa.OpComplexImag,
  2058  	opAndType{ir.OREAL, types.TCOMPLEX64}:  ssa.OpComplexReal,
  2059  	opAndType{ir.OREAL, types.TCOMPLEX128}: ssa.OpComplexReal,
  2060  
  2061  	opAndType{ir.OMUL, types.TINT8}:    ssa.OpMul8,
  2062  	opAndType{ir.OMUL, types.TUINT8}:   ssa.OpMul8,
  2063  	opAndType{ir.OMUL, types.TINT16}:   ssa.OpMul16,
  2064  	opAndType{ir.OMUL, types.TUINT16}:  ssa.OpMul16,
  2065  	opAndType{ir.OMUL, types.TINT32}:   ssa.OpMul32,
  2066  	opAndType{ir.OMUL, types.TUINT32}:  ssa.OpMul32,
  2067  	opAndType{ir.OMUL, types.TINT64}:   ssa.OpMul64,
  2068  	opAndType{ir.OMUL, types.TUINT64}:  ssa.OpMul64,
  2069  	opAndType{ir.OMUL, types.TFLOAT32}: ssa.OpMul32F,
  2070  	opAndType{ir.OMUL, types.TFLOAT64}: ssa.OpMul64F,
  2071  
  2072  	opAndType{ir.ODIV, types.TFLOAT32}: ssa.OpDiv32F,
  2073  	opAndType{ir.ODIV, types.TFLOAT64}: ssa.OpDiv64F,
  2074  
  2075  	opAndType{ir.ODIV, types.TINT8}:   ssa.OpDiv8,
  2076  	opAndType{ir.ODIV, types.TUINT8}:  ssa.OpDiv8u,
  2077  	opAndType{ir.ODIV, types.TINT16}:  ssa.OpDiv16,
  2078  	opAndType{ir.ODIV, types.TUINT16}: ssa.OpDiv16u,
  2079  	opAndType{ir.ODIV, types.TINT32}:  ssa.OpDiv32,
  2080  	opAndType{ir.ODIV, types.TUINT32}: ssa.OpDiv32u,
  2081  	opAndType{ir.ODIV, types.TINT64}:  ssa.OpDiv64,
  2082  	opAndType{ir.ODIV, types.TUINT64}: ssa.OpDiv64u,
  2083  
  2084  	opAndType{ir.OMOD, types.TINT8}:   ssa.OpMod8,
  2085  	opAndType{ir.OMOD, types.TUINT8}:  ssa.OpMod8u,
  2086  	opAndType{ir.OMOD, types.TINT16}:  ssa.OpMod16,
  2087  	opAndType{ir.OMOD, types.TUINT16}: ssa.OpMod16u,
  2088  	opAndType{ir.OMOD, types.TINT32}:  ssa.OpMod32,
  2089  	opAndType{ir.OMOD, types.TUINT32}: ssa.OpMod32u,
  2090  	opAndType{ir.OMOD, types.TINT64}:  ssa.OpMod64,
  2091  	opAndType{ir.OMOD, types.TUINT64}: ssa.OpMod64u,
  2092  
  2093  	opAndType{ir.OAND, types.TINT8}:   ssa.OpAnd8,
  2094  	opAndType{ir.OAND, types.TUINT8}:  ssa.OpAnd8,
  2095  	opAndType{ir.OAND, types.TINT16}:  ssa.OpAnd16,
  2096  	opAndType{ir.OAND, types.TUINT16}: ssa.OpAnd16,
  2097  	opAndType{ir.OAND, types.TINT32}:  ssa.OpAnd32,
  2098  	opAndType{ir.OAND, types.TUINT32}: ssa.OpAnd32,
  2099  	opAndType{ir.OAND, types.TINT64}:  ssa.OpAnd64,
  2100  	opAndType{ir.OAND, types.TUINT64}: ssa.OpAnd64,
  2101  
  2102  	opAndType{ir.OOR, types.TINT8}:   ssa.OpOr8,
  2103  	opAndType{ir.OOR, types.TUINT8}:  ssa.OpOr8,
  2104  	opAndType{ir.OOR, types.TINT16}:  ssa.OpOr16,
  2105  	opAndType{ir.OOR, types.TUINT16}: ssa.OpOr16,
  2106  	opAndType{ir.OOR, types.TINT32}:  ssa.OpOr32,
  2107  	opAndType{ir.OOR, types.TUINT32}: ssa.OpOr32,
  2108  	opAndType{ir.OOR, types.TINT64}:  ssa.OpOr64,
  2109  	opAndType{ir.OOR, types.TUINT64}: ssa.OpOr64,
  2110  
  2111  	opAndType{ir.OXOR, types.TINT8}:   ssa.OpXor8,
  2112  	opAndType{ir.OXOR, types.TUINT8}:  ssa.OpXor8,
  2113  	opAndType{ir.OXOR, types.TINT16}:  ssa.OpXor16,
  2114  	opAndType{ir.OXOR, types.TUINT16}: ssa.OpXor16,
  2115  	opAndType{ir.OXOR, types.TINT32}:  ssa.OpXor32,
  2116  	opAndType{ir.OXOR, types.TUINT32}: ssa.OpXor32,
  2117  	opAndType{ir.OXOR, types.TINT64}:  ssa.OpXor64,
  2118  	opAndType{ir.OXOR, types.TUINT64}: ssa.OpXor64,
  2119  
  2120  	opAndType{ir.OEQ, types.TBOOL}:      ssa.OpEqB,
  2121  	opAndType{ir.OEQ, types.TINT8}:      ssa.OpEq8,
  2122  	opAndType{ir.OEQ, types.TUINT8}:     ssa.OpEq8,
  2123  	opAndType{ir.OEQ, types.TINT16}:     ssa.OpEq16,
  2124  	opAndType{ir.OEQ, types.TUINT16}:    ssa.OpEq16,
  2125  	opAndType{ir.OEQ, types.TINT32}:     ssa.OpEq32,
  2126  	opAndType{ir.OEQ, types.TUINT32}:    ssa.OpEq32,
  2127  	opAndType{ir.OEQ, types.TINT64}:     ssa.OpEq64,
  2128  	opAndType{ir.OEQ, types.TUINT64}:    ssa.OpEq64,
  2129  	opAndType{ir.OEQ, types.TINTER}:     ssa.OpEqInter,
  2130  	opAndType{ir.OEQ, types.TSLICE}:     ssa.OpEqSlice,
  2131  	opAndType{ir.OEQ, types.TFUNC}:      ssa.OpEqPtr,
  2132  	opAndType{ir.OEQ, types.TMAP}:       ssa.OpEqPtr,
  2133  	opAndType{ir.OEQ, types.TCHAN}:      ssa.OpEqPtr,
  2134  	opAndType{ir.OEQ, types.TPTR}:       ssa.OpEqPtr,
  2135  	opAndType{ir.OEQ, types.TUINTPTR}:   ssa.OpEqPtr,
  2136  	opAndType{ir.OEQ, types.TUNSAFEPTR}: ssa.OpEqPtr,
  2137  	opAndType{ir.OEQ, types.TFLOAT64}:   ssa.OpEq64F,
  2138  	opAndType{ir.OEQ, types.TFLOAT32}:   ssa.OpEq32F,
  2139  
  2140  	opAndType{ir.ONE, types.TBOOL}:      ssa.OpNeqB,
  2141  	opAndType{ir.ONE, types.TINT8}:      ssa.OpNeq8,
  2142  	opAndType{ir.ONE, types.TUINT8}:     ssa.OpNeq8,
  2143  	opAndType{ir.ONE, types.TINT16}:     ssa.OpNeq16,
  2144  	opAndType{ir.ONE, types.TUINT16}:    ssa.OpNeq16,
  2145  	opAndType{ir.ONE, types.TINT32}:     ssa.OpNeq32,
  2146  	opAndType{ir.ONE, types.TUINT32}:    ssa.OpNeq32,
  2147  	opAndType{ir.ONE, types.TINT64}:     ssa.OpNeq64,
  2148  	opAndType{ir.ONE, types.TUINT64}:    ssa.OpNeq64,
  2149  	opAndType{ir.ONE, types.TINTER}:     ssa.OpNeqInter,
  2150  	opAndType{ir.ONE, types.TSLICE}:     ssa.OpNeqSlice,
  2151  	opAndType{ir.ONE, types.TFUNC}:      ssa.OpNeqPtr,
  2152  	opAndType{ir.ONE, types.TMAP}:       ssa.OpNeqPtr,
  2153  	opAndType{ir.ONE, types.TCHAN}:      ssa.OpNeqPtr,
  2154  	opAndType{ir.ONE, types.TPTR}:       ssa.OpNeqPtr,
  2155  	opAndType{ir.ONE, types.TUINTPTR}:   ssa.OpNeqPtr,
  2156  	opAndType{ir.ONE, types.TUNSAFEPTR}: ssa.OpNeqPtr,
  2157  	opAndType{ir.ONE, types.TFLOAT64}:   ssa.OpNeq64F,
  2158  	opAndType{ir.ONE, types.TFLOAT32}:   ssa.OpNeq32F,
  2159  
  2160  	opAndType{ir.OLT, types.TINT8}:    ssa.OpLess8,
  2161  	opAndType{ir.OLT, types.TUINT8}:   ssa.OpLess8U,
  2162  	opAndType{ir.OLT, types.TINT16}:   ssa.OpLess16,
  2163  	opAndType{ir.OLT, types.TUINT16}:  ssa.OpLess16U,
  2164  	opAndType{ir.OLT, types.TINT32}:   ssa.OpLess32,
  2165  	opAndType{ir.OLT, types.TUINT32}:  ssa.OpLess32U,
  2166  	opAndType{ir.OLT, types.TINT64}:   ssa.OpLess64,
  2167  	opAndType{ir.OLT, types.TUINT64}:  ssa.OpLess64U,
  2168  	opAndType{ir.OLT, types.TFLOAT64}: ssa.OpLess64F,
  2169  	opAndType{ir.OLT, types.TFLOAT32}: ssa.OpLess32F,
  2170  
  2171  	opAndType{ir.OLE, types.TINT8}:    ssa.OpLeq8,
  2172  	opAndType{ir.OLE, types.TUINT8}:   ssa.OpLeq8U,
  2173  	opAndType{ir.OLE, types.TINT16}:   ssa.OpLeq16,
  2174  	opAndType{ir.OLE, types.TUINT16}:  ssa.OpLeq16U,
  2175  	opAndType{ir.OLE, types.TINT32}:   ssa.OpLeq32,
  2176  	opAndType{ir.OLE, types.TUINT32}:  ssa.OpLeq32U,
  2177  	opAndType{ir.OLE, types.TINT64}:   ssa.OpLeq64,
  2178  	opAndType{ir.OLE, types.TUINT64}:  ssa.OpLeq64U,
  2179  	opAndType{ir.OLE, types.TFLOAT64}: ssa.OpLeq64F,
  2180  	opAndType{ir.OLE, types.TFLOAT32}: ssa.OpLeq32F,
  2181  }
  2182  
  2183  func (s *state) concreteEtype(t *types.Type) types.Kind {
  2184  	e := t.Kind()
  2185  	switch e {
  2186  	default:
  2187  		return e
  2188  	case types.TINT:
  2189  		if s.config.PtrSize == 8 {
  2190  			return types.TINT64
  2191  		}
  2192  		return types.TINT32
  2193  	case types.TUINT:
  2194  		if s.config.PtrSize == 8 {
  2195  			return types.TUINT64
  2196  		}
  2197  		return types.TUINT32
  2198  	case types.TUINTPTR:
  2199  		if s.config.PtrSize == 8 {
  2200  			return types.TUINT64
  2201  		}
  2202  		return types.TUINT32
  2203  	}
  2204  }
  2205  
  2206  func (s *state) ssaOp(op ir.Op, t *types.Type) ssa.Op {
  2207  	etype := s.concreteEtype(t)
  2208  	x, ok := opToSSA[opAndType{op, etype}]
  2209  	if !ok {
  2210  		s.Fatalf("unhandled binary op %v %s", op, etype)
  2211  	}
  2212  	return x
  2213  }
  2214  
  2215  type opAndTwoTypes struct {
  2216  	op     ir.Op
  2217  	etype1 types.Kind
  2218  	etype2 types.Kind
  2219  }
  2220  
  2221  type twoTypes struct {
  2222  	etype1 types.Kind
  2223  	etype2 types.Kind
  2224  }
  2225  
  2226  type twoOpsAndType struct {
  2227  	op1              ssa.Op
  2228  	op2              ssa.Op
  2229  	intermediateType types.Kind
  2230  }
  2231  
  2232  var fpConvOpToSSA = map[twoTypes]twoOpsAndType{
  2233  
  2234  	twoTypes{types.TINT8, types.TFLOAT32}:  twoOpsAndType{ssa.OpSignExt8to32, ssa.OpCvt32to32F, types.TINT32},
  2235  	twoTypes{types.TINT16, types.TFLOAT32}: twoOpsAndType{ssa.OpSignExt16to32, ssa.OpCvt32to32F, types.TINT32},
  2236  	twoTypes{types.TINT32, types.TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt32to32F, types.TINT32},
  2237  	twoTypes{types.TINT64, types.TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt64to32F, types.TINT64},
  2238  
  2239  	twoTypes{types.TINT8, types.TFLOAT64}:  twoOpsAndType{ssa.OpSignExt8to32, ssa.OpCvt32to64F, types.TINT32},
  2240  	twoTypes{types.TINT16, types.TFLOAT64}: twoOpsAndType{ssa.OpSignExt16to32, ssa.OpCvt32to64F, types.TINT32},
  2241  	twoTypes{types.TINT32, types.TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt32to64F, types.TINT32},
  2242  	twoTypes{types.TINT64, types.TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt64to64F, types.TINT64},
  2243  
  2244  	twoTypes{types.TFLOAT32, types.TINT8}:  twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
  2245  	twoTypes{types.TFLOAT32, types.TINT16}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
  2246  	twoTypes{types.TFLOAT32, types.TINT32}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpCopy, types.TINT32},
  2247  	twoTypes{types.TFLOAT32, types.TINT64}: twoOpsAndType{ssa.OpCvt32Fto64, ssa.OpCopy, types.TINT64},
  2248  
  2249  	twoTypes{types.TFLOAT64, types.TINT8}:  twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
  2250  	twoTypes{types.TFLOAT64, types.TINT16}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
  2251  	twoTypes{types.TFLOAT64, types.TINT32}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpCopy, types.TINT32},
  2252  	twoTypes{types.TFLOAT64, types.TINT64}: twoOpsAndType{ssa.OpCvt64Fto64, ssa.OpCopy, types.TINT64},
  2253  	// unsigned
  2254  	twoTypes{types.TUINT8, types.TFLOAT32}:  twoOpsAndType{ssa.OpZeroExt8to32, ssa.OpCvt32to32F, types.TINT32},
  2255  	twoTypes{types.TUINT16, types.TFLOAT32}: twoOpsAndType{ssa.OpZeroExt16to32, ssa.OpCvt32to32F, types.TINT32},
  2256  	twoTypes{types.TUINT32, types.TFLOAT32}: twoOpsAndType{ssa.OpZeroExt32to64, ssa.OpCvt64to32F, types.TINT64}, // go wide to dodge unsigned
  2257  	twoTypes{types.TUINT64, types.TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpInvalid, types.TUINT64},            // Cvt64Uto32F, branchy code expansion instead
  2258  
  2259  	twoTypes{types.TUINT8, types.TFLOAT64}:  twoOpsAndType{ssa.OpZeroExt8to32, ssa.OpCvt32to64F, types.TINT32},
  2260  	twoTypes{types.TUINT16, types.TFLOAT64}: twoOpsAndType{ssa.OpZeroExt16to32, ssa.OpCvt32to64F, types.TINT32},
  2261  	twoTypes{types.TUINT32, types.TFLOAT64}: twoOpsAndType{ssa.OpZeroExt32to64, ssa.OpCvt64to64F, types.TINT64}, // go wide to dodge unsigned
  2262  	twoTypes{types.TUINT64, types.TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpInvalid, types.TUINT64},            // Cvt64Uto64F, branchy code expansion instead
  2263  
  2264  	twoTypes{types.TFLOAT32, types.TUINT8}:  twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
  2265  	twoTypes{types.TFLOAT32, types.TUINT16}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
  2266  	twoTypes{types.TFLOAT32, types.TUINT32}: twoOpsAndType{ssa.OpCvt32Fto64, ssa.OpTrunc64to32, types.TINT64}, // go wide to dodge unsigned
  2267  	twoTypes{types.TFLOAT32, types.TUINT64}: twoOpsAndType{ssa.OpInvalid, ssa.OpCopy, types.TUINT64},          // Cvt32Fto64U, branchy code expansion instead
  2268  
  2269  	twoTypes{types.TFLOAT64, types.TUINT8}:  twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
  2270  	twoTypes{types.TFLOAT64, types.TUINT16}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
  2271  	twoTypes{types.TFLOAT64, types.TUINT32}: twoOpsAndType{ssa.OpCvt64Fto64, ssa.OpTrunc64to32, types.TINT64}, // go wide to dodge unsigned
  2272  	twoTypes{types.TFLOAT64, types.TUINT64}: twoOpsAndType{ssa.OpInvalid, ssa.OpCopy, types.TUINT64},          // Cvt64Fto64U, branchy code expansion instead
  2273  
  2274  	// float
  2275  	twoTypes{types.TFLOAT64, types.TFLOAT32}: twoOpsAndType{ssa.OpCvt64Fto32F, ssa.OpCopy, types.TFLOAT32},
  2276  	twoTypes{types.TFLOAT64, types.TFLOAT64}: twoOpsAndType{ssa.OpRound64F, ssa.OpCopy, types.TFLOAT64},
  2277  	twoTypes{types.TFLOAT32, types.TFLOAT32}: twoOpsAndType{ssa.OpRound32F, ssa.OpCopy, types.TFLOAT32},
  2278  	twoTypes{types.TFLOAT32, types.TFLOAT64}: twoOpsAndType{ssa.OpCvt32Fto64F, ssa.OpCopy, types.TFLOAT64},
  2279  }
  2280  
  2281  // this map is used only for 32-bit arch, and only includes the difference
  2282  // on 32-bit arch, don't use int64<->float conversion for uint32
  2283  var fpConvOpToSSA32 = map[twoTypes]twoOpsAndType{
  2284  	twoTypes{types.TUINT32, types.TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt32Uto32F, types.TUINT32},
  2285  	twoTypes{types.TUINT32, types.TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt32Uto64F, types.TUINT32},
  2286  	twoTypes{types.TFLOAT32, types.TUINT32}: twoOpsAndType{ssa.OpCvt32Fto32U, ssa.OpCopy, types.TUINT32},
  2287  	twoTypes{types.TFLOAT64, types.TUINT32}: twoOpsAndType{ssa.OpCvt64Fto32U, ssa.OpCopy, types.TUINT32},
  2288  }
  2289  
  2290  // uint64<->float conversions, only on machines that have instructions for that
  2291  var uint64fpConvOpToSSA = map[twoTypes]twoOpsAndType{
  2292  	twoTypes{types.TUINT64, types.TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt64Uto32F, types.TUINT64},
  2293  	twoTypes{types.TUINT64, types.TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt64Uto64F, types.TUINT64},
  2294  	twoTypes{types.TFLOAT32, types.TUINT64}: twoOpsAndType{ssa.OpCvt32Fto64U, ssa.OpCopy, types.TUINT64},
  2295  	twoTypes{types.TFLOAT64, types.TUINT64}: twoOpsAndType{ssa.OpCvt64Fto64U, ssa.OpCopy, types.TUINT64},
  2296  }
  2297  
  2298  var shiftOpToSSA = map[opAndTwoTypes]ssa.Op{
  2299  	opAndTwoTypes{ir.OLSH, types.TINT8, types.TUINT8}:   ssa.OpLsh8x8,
  2300  	opAndTwoTypes{ir.OLSH, types.TUINT8, types.TUINT8}:  ssa.OpLsh8x8,
  2301  	opAndTwoTypes{ir.OLSH, types.TINT8, types.TUINT16}:  ssa.OpLsh8x16,
  2302  	opAndTwoTypes{ir.OLSH, types.TUINT8, types.TUINT16}: ssa.OpLsh8x16,
  2303  	opAndTwoTypes{ir.OLSH, types.TINT8, types.TUINT32}:  ssa.OpLsh8x32,
  2304  	opAndTwoTypes{ir.OLSH, types.TUINT8, types.TUINT32}: ssa.OpLsh8x32,
  2305  	opAndTwoTypes{ir.OLSH, types.TINT8, types.TUINT64}:  ssa.OpLsh8x64,
  2306  	opAndTwoTypes{ir.OLSH, types.TUINT8, types.TUINT64}: ssa.OpLsh8x64,
  2307  
  2308  	opAndTwoTypes{ir.OLSH, types.TINT16, types.TUINT8}:   ssa.OpLsh16x8,
  2309  	opAndTwoTypes{ir.OLSH, types.TUINT16, types.TUINT8}:  ssa.OpLsh16x8,
  2310  	opAndTwoTypes{ir.OLSH, types.TINT16, types.TUINT16}:  ssa.OpLsh16x16,
  2311  	opAndTwoTypes{ir.OLSH, types.TUINT16, types.TUINT16}: ssa.OpLsh16x16,
  2312  	opAndTwoTypes{ir.OLSH, types.TINT16, types.TUINT32}:  ssa.OpLsh16x32,
  2313  	opAndTwoTypes{ir.OLSH, types.TUINT16, types.TUINT32}: ssa.OpLsh16x32,
  2314  	opAndTwoTypes{ir.OLSH, types.TINT16, types.TUINT64}:  ssa.OpLsh16x64,
  2315  	opAndTwoTypes{ir.OLSH, types.TUINT16, types.TUINT64}: ssa.OpLsh16x64,
  2316  
  2317  	opAndTwoTypes{ir.OLSH, types.TINT32, types.TUINT8}:   ssa.OpLsh32x8,
  2318  	opAndTwoTypes{ir.OLSH, types.TUINT32, types.TUINT8}:  ssa.OpLsh32x8,
  2319  	opAndTwoTypes{ir.OLSH, types.TINT32, types.TUINT16}:  ssa.OpLsh32x16,
  2320  	opAndTwoTypes{ir.OLSH, types.TUINT32, types.TUINT16}: ssa.OpLsh32x16,
  2321  	opAndTwoTypes{ir.OLSH, types.TINT32, types.TUINT32}:  ssa.OpLsh32x32,
  2322  	opAndTwoTypes{ir.OLSH, types.TUINT32, types.TUINT32}: ssa.OpLsh32x32,
  2323  	opAndTwoTypes{ir.OLSH, types.TINT32, types.TUINT64}:  ssa.OpLsh32x64,
  2324  	opAndTwoTypes{ir.OLSH, types.TUINT32, types.TUINT64}: ssa.OpLsh32x64,
  2325  
  2326  	opAndTwoTypes{ir.OLSH, types.TINT64, types.TUINT8}:   ssa.OpLsh64x8,
  2327  	opAndTwoTypes{ir.OLSH, types.TUINT64, types.TUINT8}:  ssa.OpLsh64x8,
  2328  	opAndTwoTypes{ir.OLSH, types.TINT64, types.TUINT16}:  ssa.OpLsh64x16,
  2329  	opAndTwoTypes{ir.OLSH, types.TUINT64, types.TUINT16}: ssa.OpLsh64x16,
  2330  	opAndTwoTypes{ir.OLSH, types.TINT64, types.TUINT32}:  ssa.OpLsh64x32,
  2331  	opAndTwoTypes{ir.OLSH, types.TUINT64, types.TUINT32}: ssa.OpLsh64x32,
  2332  	opAndTwoTypes{ir.OLSH, types.TINT64, types.TUINT64}:  ssa.OpLsh64x64,
  2333  	opAndTwoTypes{ir.OLSH, types.TUINT64, types.TUINT64}: ssa.OpLsh64x64,
  2334  
  2335  	opAndTwoTypes{ir.ORSH, types.TINT8, types.TUINT8}:   ssa.OpRsh8x8,
  2336  	opAndTwoTypes{ir.ORSH, types.TUINT8, types.TUINT8}:  ssa.OpRsh8Ux8,
  2337  	opAndTwoTypes{ir.ORSH, types.TINT8, types.TUINT16}:  ssa.OpRsh8x16,
  2338  	opAndTwoTypes{ir.ORSH, types.TUINT8, types.TUINT16}: ssa.OpRsh8Ux16,
  2339  	opAndTwoTypes{ir.ORSH, types.TINT8, types.TUINT32}:  ssa.OpRsh8x32,
  2340  	opAndTwoTypes{ir.ORSH, types.TUINT8, types.TUINT32}: ssa.OpRsh8Ux32,
  2341  	opAndTwoTypes{ir.ORSH, types.TINT8, types.TUINT64}:  ssa.OpRsh8x64,
  2342  	opAndTwoTypes{ir.ORSH, types.TUINT8, types.TUINT64}: ssa.OpRsh8Ux64,
  2343  
  2344  	opAndTwoTypes{ir.ORSH, types.TINT16, types.TUINT8}:   ssa.OpRsh16x8,
  2345  	opAndTwoTypes{ir.ORSH, types.TUINT16, types.TUINT8}:  ssa.OpRsh16Ux8,
  2346  	opAndTwoTypes{ir.ORSH, types.TINT16, types.TUINT16}:  ssa.OpRsh16x16,
  2347  	opAndTwoTypes{ir.ORSH, types.TUINT16, types.TUINT16}: ssa.OpRsh16Ux16,
  2348  	opAndTwoTypes{ir.ORSH, types.TINT16, types.TUINT32}:  ssa.OpRsh16x32,
  2349  	opAndTwoTypes{ir.ORSH, types.TUINT16, types.TUINT32}: ssa.OpRsh16Ux32,
  2350  	opAndTwoTypes{ir.ORSH, types.TINT16, types.TUINT64}:  ssa.OpRsh16x64,
  2351  	opAndTwoTypes{ir.ORSH, types.TUINT16, types.TUINT64}: ssa.OpRsh16Ux64,
  2352  
  2353  	opAndTwoTypes{ir.ORSH, types.TINT32, types.TUINT8}:   ssa.OpRsh32x8,
  2354  	opAndTwoTypes{ir.ORSH, types.TUINT32, types.TUINT8}:  ssa.OpRsh32Ux8,
  2355  	opAndTwoTypes{ir.ORSH, types.TINT32, types.TUINT16}:  ssa.OpRsh32x16,
  2356  	opAndTwoTypes{ir.ORSH, types.TUINT32, types.TUINT16}: ssa.OpRsh32Ux16,
  2357  	opAndTwoTypes{ir.ORSH, types.TINT32, types.TUINT32}:  ssa.OpRsh32x32,
  2358  	opAndTwoTypes{ir.ORSH, types.TUINT32, types.TUINT32}: ssa.OpRsh32Ux32,
  2359  	opAndTwoTypes{ir.ORSH, types.TINT32, types.TUINT64}:  ssa.OpRsh32x64,
  2360  	opAndTwoTypes{ir.ORSH, types.TUINT32, types.TUINT64}: ssa.OpRsh32Ux64,
  2361  
  2362  	opAndTwoTypes{ir.ORSH, types.TINT64, types.TUINT8}:   ssa.OpRsh64x8,
  2363  	opAndTwoTypes{ir.ORSH, types.TUINT64, types.TUINT8}:  ssa.OpRsh64Ux8,
  2364  	opAndTwoTypes{ir.ORSH, types.TINT64, types.TUINT16}:  ssa.OpRsh64x16,
  2365  	opAndTwoTypes{ir.ORSH, types.TUINT64, types.TUINT16}: ssa.OpRsh64Ux16,
  2366  	opAndTwoTypes{ir.ORSH, types.TINT64, types.TUINT32}:  ssa.OpRsh64x32,
  2367  	opAndTwoTypes{ir.ORSH, types.TUINT64, types.TUINT32}: ssa.OpRsh64Ux32,
  2368  	opAndTwoTypes{ir.ORSH, types.TINT64, types.TUINT64}:  ssa.OpRsh64x64,
  2369  	opAndTwoTypes{ir.ORSH, types.TUINT64, types.TUINT64}: ssa.OpRsh64Ux64,
  2370  }
  2371  
  2372  func (s *state) ssaShiftOp(op ir.Op, t *types.Type, u *types.Type) ssa.Op {
  2373  	etype1 := s.concreteEtype(t)
  2374  	etype2 := s.concreteEtype(u)
  2375  	x, ok := shiftOpToSSA[opAndTwoTypes{op, etype1, etype2}]
  2376  	if !ok {
  2377  		s.Fatalf("unhandled shift op %v etype=%s/%s", op, etype1, etype2)
  2378  	}
  2379  	return x
  2380  }
  2381  
  2382  func (s *state) conv(n ir.Node, v *ssa.Value, ft, tt *types.Type) *ssa.Value {
  2383  	if ft.IsBoolean() && tt.IsKind(types.TUINT8) {
  2384  		// Bool -> uint8 is generated internally when indexing into runtime.staticbyte.
  2385  		return s.newValue1(ssa.OpCopy, tt, v)
  2386  	}
  2387  	if ft.IsInteger() && tt.IsInteger() {
  2388  		var op ssa.Op
  2389  		if tt.Size() == ft.Size() {
  2390  			op = ssa.OpCopy
  2391  		} else if tt.Size() < ft.Size() {
  2392  			// truncation
  2393  			switch 10*ft.Size() + tt.Size() {
  2394  			case 21:
  2395  				op = ssa.OpTrunc16to8
  2396  			case 41:
  2397  				op = ssa.OpTrunc32to8
  2398  			case 42:
  2399  				op = ssa.OpTrunc32to16
  2400  			case 81:
  2401  				op = ssa.OpTrunc64to8
  2402  			case 82:
  2403  				op = ssa.OpTrunc64to16
  2404  			case 84:
  2405  				op = ssa.OpTrunc64to32
  2406  			default:
  2407  				s.Fatalf("weird integer truncation %v -> %v", ft, tt)
  2408  			}
  2409  		} else if ft.IsSigned() {
  2410  			// sign extension
  2411  			switch 10*ft.Size() + tt.Size() {
  2412  			case 12:
  2413  				op = ssa.OpSignExt8to16
  2414  			case 14:
  2415  				op = ssa.OpSignExt8to32
  2416  			case 18:
  2417  				op = ssa.OpSignExt8to64
  2418  			case 24:
  2419  				op = ssa.OpSignExt16to32
  2420  			case 28:
  2421  				op = ssa.OpSignExt16to64
  2422  			case 48:
  2423  				op = ssa.OpSignExt32to64
  2424  			default:
  2425  				s.Fatalf("bad integer sign extension %v -> %v", ft, tt)
  2426  			}
  2427  		} else {
  2428  			// zero extension
  2429  			switch 10*ft.Size() + tt.Size() {
  2430  			case 12:
  2431  				op = ssa.OpZeroExt8to16
  2432  			case 14:
  2433  				op = ssa.OpZeroExt8to32
  2434  			case 18:
  2435  				op = ssa.OpZeroExt8to64
  2436  			case 24:
  2437  				op = ssa.OpZeroExt16to32
  2438  			case 28:
  2439  				op = ssa.OpZeroExt16to64
  2440  			case 48:
  2441  				op = ssa.OpZeroExt32to64
  2442  			default:
  2443  				s.Fatalf("weird integer sign extension %v -> %v", ft, tt)
  2444  			}
  2445  		}
  2446  		return s.newValue1(op, tt, v)
  2447  	}
  2448  
  2449  	if ft.IsComplex() && tt.IsComplex() {
  2450  		var op ssa.Op
  2451  		if ft.Size() == tt.Size() {
  2452  			switch ft.Size() {
  2453  			case 8:
  2454  				op = ssa.OpRound32F
  2455  			case 16:
  2456  				op = ssa.OpRound64F
  2457  			default:
  2458  				s.Fatalf("weird complex conversion %v -> %v", ft, tt)
  2459  			}
  2460  		} else if ft.Size() == 8 && tt.Size() == 16 {
  2461  			op = ssa.OpCvt32Fto64F
  2462  		} else if ft.Size() == 16 && tt.Size() == 8 {
  2463  			op = ssa.OpCvt64Fto32F
  2464  		} else {
  2465  			s.Fatalf("weird complex conversion %v -> %v", ft, tt)
  2466  		}
  2467  		ftp := types.FloatForComplex(ft)
  2468  		ttp := types.FloatForComplex(tt)
  2469  		return s.newValue2(ssa.OpComplexMake, tt,
  2470  			s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexReal, ftp, v)),
  2471  			s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexImag, ftp, v)))
  2472  	}
  2473  
  2474  	if tt.IsComplex() { // and ft is not complex
  2475  		// Needed for generics support - can't happen in normal Go code.
  2476  		et := types.FloatForComplex(tt)
  2477  		v = s.conv(n, v, ft, et)
  2478  		return s.newValue2(ssa.OpComplexMake, tt, v, s.zeroVal(et))
  2479  	}
  2480  
  2481  	if ft.IsFloat() || tt.IsFloat() {
  2482  		conv, ok := fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]
  2483  		if s.config.RegSize == 4 && Arch.LinkArch.Family != sys.MIPS && !s.softFloat {
  2484  			if conv1, ok1 := fpConvOpToSSA32[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
  2485  				conv = conv1
  2486  			}
  2487  		}
  2488  		if Arch.LinkArch.Family == sys.ARM64 || Arch.LinkArch.Family == sys.Wasm || Arch.LinkArch.Family == sys.S390X || s.softFloat {
  2489  			if conv1, ok1 := uint64fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
  2490  				conv = conv1
  2491  			}
  2492  		}
  2493  
  2494  		if Arch.LinkArch.Family == sys.MIPS && !s.softFloat {
  2495  			if ft.Size() == 4 && ft.IsInteger() && !ft.IsSigned() {
  2496  				// tt is float32 or float64, and ft is also unsigned
  2497  				if tt.Size() == 4 {
  2498  					return s.uint32Tofloat32(n, v, ft, tt)
  2499  				}
  2500  				if tt.Size() == 8 {
  2501  					return s.uint32Tofloat64(n, v, ft, tt)
  2502  				}
  2503  			} else if tt.Size() == 4 && tt.IsInteger() && !tt.IsSigned() {
  2504  				// ft is float32 or float64, and tt is unsigned integer
  2505  				if ft.Size() == 4 {
  2506  					return s.float32ToUint32(n, v, ft, tt)
  2507  				}
  2508  				if ft.Size() == 8 {
  2509  					return s.float64ToUint32(n, v, ft, tt)
  2510  				}
  2511  			}
  2512  		}
  2513  
  2514  		if !ok {
  2515  			s.Fatalf("weird float conversion %v -> %v", ft, tt)
  2516  		}
  2517  		op1, op2, it := conv.op1, conv.op2, conv.intermediateType
  2518  
  2519  		if op1 != ssa.OpInvalid && op2 != ssa.OpInvalid {
  2520  			// normal case, not tripping over unsigned 64
  2521  			if op1 == ssa.OpCopy {
  2522  				if op2 == ssa.OpCopy {
  2523  					return v
  2524  				}
  2525  				return s.newValueOrSfCall1(op2, tt, v)
  2526  			}
  2527  			if op2 == ssa.OpCopy {
  2528  				return s.newValueOrSfCall1(op1, tt, v)
  2529  			}
  2530  			return s.newValueOrSfCall1(op2, tt, s.newValueOrSfCall1(op1, types.Types[it], v))
  2531  		}
  2532  		// Tricky 64-bit unsigned cases.
  2533  		if ft.IsInteger() {
  2534  			// tt is float32 or float64, and ft is also unsigned
  2535  			if tt.Size() == 4 {
  2536  				return s.uint64Tofloat32(n, v, ft, tt)
  2537  			}
  2538  			if tt.Size() == 8 {
  2539  				return s.uint64Tofloat64(n, v, ft, tt)
  2540  			}
  2541  			s.Fatalf("weird unsigned integer to float conversion %v -> %v", ft, tt)
  2542  		}
  2543  		// ft is float32 or float64, and tt is unsigned integer
  2544  		if ft.Size() == 4 {
  2545  			return s.float32ToUint64(n, v, ft, tt)
  2546  		}
  2547  		if ft.Size() == 8 {
  2548  			return s.float64ToUint64(n, v, ft, tt)
  2549  		}
  2550  		s.Fatalf("weird float to unsigned integer conversion %v -> %v", ft, tt)
  2551  		return nil
  2552  	}
  2553  
  2554  	s.Fatalf("unhandled OCONV %s -> %s", ft.Kind(), tt.Kind())
  2555  	return nil
  2556  }
  2557  
  2558  // expr converts the expression n to ssa, adds it to s and returns the ssa result.
  2559  func (s *state) expr(n ir.Node) *ssa.Value {
  2560  	return s.exprCheckPtr(n, true)
  2561  }
  2562  
  2563  func (s *state) exprCheckPtr(n ir.Node, checkPtrOK bool) *ssa.Value {
  2564  	if ir.HasUniquePos(n) {
  2565  		// ONAMEs and named OLITERALs have the line number
  2566  		// of the decl, not the use. See issue 14742.
  2567  		s.pushLine(n.Pos())
  2568  		defer s.popLine()
  2569  	}
  2570  
  2571  	s.stmtList(n.Init())
  2572  	switch n.Op() {
  2573  	case ir.OBYTES2STRTMP:
  2574  		n := n.(*ir.ConvExpr)
  2575  		slice := s.expr(n.X)
  2576  		ptr := s.newValue1(ssa.OpSlicePtr, s.f.Config.Types.BytePtr, slice)
  2577  		len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  2578  		return s.newValue2(ssa.OpStringMake, n.Type(), ptr, len)
  2579  	case ir.OSTR2BYTESTMP:
  2580  		n := n.(*ir.ConvExpr)
  2581  		str := s.expr(n.X)
  2582  		ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, str)
  2583  		len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], str)
  2584  		return s.newValue3(ssa.OpSliceMake, n.Type(), ptr, len, len)
  2585  	case ir.OCFUNC:
  2586  		n := n.(*ir.UnaryExpr)
  2587  		aux := n.X.(*ir.Name).Linksym()
  2588  		// OCFUNC is used to build function values, which must
  2589  		// always reference ABIInternal entry points.
  2590  		if aux.ABI() != obj.ABIInternal {
  2591  			s.Fatalf("expected ABIInternal: %v", aux.ABI())
  2592  		}
  2593  		return s.entryNewValue1A(ssa.OpAddr, n.Type(), aux, s.sb)
  2594  	case ir.ONAME:
  2595  		n := n.(*ir.Name)
  2596  		if n.Class == ir.PFUNC {
  2597  			// "value" of a function is the address of the function's closure
  2598  			sym := staticdata.FuncLinksym(n)
  2599  			return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(n.Type()), sym, s.sb)
  2600  		}
  2601  		if s.canSSA(n) {
  2602  			return s.variable(n, n.Type())
  2603  		}
  2604  		return s.load(n.Type(), s.addr(n))
  2605  	case ir.OLINKSYMOFFSET:
  2606  		n := n.(*ir.LinksymOffsetExpr)
  2607  		return s.load(n.Type(), s.addr(n))
  2608  	case ir.ONIL:
  2609  		n := n.(*ir.NilExpr)
  2610  		t := n.Type()
  2611  		switch {
  2612  		case t.IsSlice():
  2613  			return s.constSlice(t)
  2614  		case t.IsInterface():
  2615  			return s.constInterface(t)
  2616  		default:
  2617  			return s.constNil(t)
  2618  		}
  2619  	case ir.OLITERAL:
  2620  		switch u := n.Val(); u.Kind() {
  2621  		case constant.Int:
  2622  			i := ir.IntVal(n.Type(), u)
  2623  			switch n.Type().Size() {
  2624  			case 1:
  2625  				return s.constInt8(n.Type(), int8(i))
  2626  			case 2:
  2627  				return s.constInt16(n.Type(), int16(i))
  2628  			case 4:
  2629  				return s.constInt32(n.Type(), int32(i))
  2630  			case 8:
  2631  				return s.constInt64(n.Type(), i)
  2632  			default:
  2633  				s.Fatalf("bad integer size %d", n.Type().Size())
  2634  				return nil
  2635  			}
  2636  		case constant.String:
  2637  			i := constant.StringVal(u)
  2638  			if i == "" {
  2639  				return s.constEmptyString(n.Type())
  2640  			}
  2641  			return s.entryNewValue0A(ssa.OpConstString, n.Type(), ssa.StringToAux(i))
  2642  		case constant.Bool:
  2643  			return s.constBool(constant.BoolVal(u))
  2644  		case constant.Float:
  2645  			f, _ := constant.Float64Val(u)
  2646  			switch n.Type().Size() {
  2647  			case 4:
  2648  				return s.constFloat32(n.Type(), f)
  2649  			case 8:
  2650  				return s.constFloat64(n.Type(), f)
  2651  			default:
  2652  				s.Fatalf("bad float size %d", n.Type().Size())
  2653  				return nil
  2654  			}
  2655  		case constant.Complex:
  2656  			re, _ := constant.Float64Val(constant.Real(u))
  2657  			im, _ := constant.Float64Val(constant.Imag(u))
  2658  			switch n.Type().Size() {
  2659  			case 8:
  2660  				pt := types.Types[types.TFLOAT32]
  2661  				return s.newValue2(ssa.OpComplexMake, n.Type(),
  2662  					s.constFloat32(pt, re),
  2663  					s.constFloat32(pt, im))
  2664  			case 16:
  2665  				pt := types.Types[types.TFLOAT64]
  2666  				return s.newValue2(ssa.OpComplexMake, n.Type(),
  2667  					s.constFloat64(pt, re),
  2668  					s.constFloat64(pt, im))
  2669  			default:
  2670  				s.Fatalf("bad complex size %d", n.Type().Size())
  2671  				return nil
  2672  			}
  2673  		default:
  2674  			s.Fatalf("unhandled OLITERAL %v", u.Kind())
  2675  			return nil
  2676  		}
  2677  	case ir.OCONVNOP:
  2678  		n := n.(*ir.ConvExpr)
  2679  		to := n.Type()
  2680  		from := n.X.Type()
  2681  
  2682  		// Assume everything will work out, so set up our return value.
  2683  		// Anything interesting that happens from here is a fatal.
  2684  		x := s.expr(n.X)
  2685  		if to == from {
  2686  			return x
  2687  		}
  2688  
  2689  		// Special case for not confusing GC and liveness.
  2690  		// We don't want pointers accidentally classified
  2691  		// as not-pointers or vice-versa because of copy
  2692  		// elision.
  2693  		if to.IsPtrShaped() != from.IsPtrShaped() {
  2694  			return s.newValue2(ssa.OpConvert, to, x, s.mem())
  2695  		}
  2696  
  2697  		v := s.newValue1(ssa.OpCopy, to, x) // ensure that v has the right type
  2698  
  2699  		// CONVNOP closure
  2700  		if to.Kind() == types.TFUNC && from.IsPtrShaped() {
  2701  			return v
  2702  		}
  2703  
  2704  		// named <--> unnamed type or typed <--> untyped const
  2705  		if from.Kind() == to.Kind() {
  2706  			return v
  2707  		}
  2708  
  2709  		// unsafe.Pointer <--> *T
  2710  		if to.IsUnsafePtr() && from.IsPtrShaped() || from.IsUnsafePtr() && to.IsPtrShaped() {
  2711  			if s.checkPtrEnabled && checkPtrOK && to.IsPtr() && from.IsUnsafePtr() {
  2712  				s.checkPtrAlignment(n, v, nil)
  2713  			}
  2714  			return v
  2715  		}
  2716  
  2717  		// map <--> *hmap
  2718  		if to.Kind() == types.TMAP && from.IsPtr() &&
  2719  			to.MapType().Hmap == from.Elem() {
  2720  			return v
  2721  		}
  2722  
  2723  		types.CalcSize(from)
  2724  		types.CalcSize(to)
  2725  		if from.Size() != to.Size() {
  2726  			s.Fatalf("CONVNOP width mismatch %v (%d) -> %v (%d)\n", from, from.Size(), to, to.Size())
  2727  			return nil
  2728  		}
  2729  		if etypesign(from.Kind()) != etypesign(to.Kind()) {
  2730  			s.Fatalf("CONVNOP sign mismatch %v (%s) -> %v (%s)\n", from, from.Kind(), to, to.Kind())
  2731  			return nil
  2732  		}
  2733  
  2734  		if base.Flag.Cfg.Instrumenting {
  2735  			// These appear to be fine, but they fail the
  2736  			// integer constraint below, so okay them here.
  2737  			// Sample non-integer conversion: map[string]string -> *uint8
  2738  			return v
  2739  		}
  2740  
  2741  		if etypesign(from.Kind()) == 0 {
  2742  			s.Fatalf("CONVNOP unrecognized non-integer %v -> %v\n", from, to)
  2743  			return nil
  2744  		}
  2745  
  2746  		// integer, same width, same sign
  2747  		return v
  2748  
  2749  	case ir.OCONV:
  2750  		n := n.(*ir.ConvExpr)
  2751  		x := s.expr(n.X)
  2752  		return s.conv(n, x, n.X.Type(), n.Type())
  2753  
  2754  	case ir.ODOTTYPE:
  2755  		n := n.(*ir.TypeAssertExpr)
  2756  		res, _ := s.dottype(n, false)
  2757  		return res
  2758  
  2759  	case ir.ODYNAMICDOTTYPE:
  2760  		n := n.(*ir.DynamicTypeAssertExpr)
  2761  		res, _ := s.dynamicDottype(n, false)
  2762  		return res
  2763  
  2764  	// binary ops
  2765  	case ir.OLT, ir.OEQ, ir.ONE, ir.OLE, ir.OGE, ir.OGT:
  2766  		n := n.(*ir.BinaryExpr)
  2767  		a := s.expr(n.X)
  2768  		b := s.expr(n.Y)
  2769  		if n.X.Type().IsComplex() {
  2770  			pt := types.FloatForComplex(n.X.Type())
  2771  			op := s.ssaOp(ir.OEQ, pt)
  2772  			r := s.newValueOrSfCall2(op, types.Types[types.TBOOL], s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b))
  2773  			i := s.newValueOrSfCall2(op, types.Types[types.TBOOL], s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b))
  2774  			c := s.newValue2(ssa.OpAndB, types.Types[types.TBOOL], r, i)
  2775  			switch n.Op() {
  2776  			case ir.OEQ:
  2777  				return c
  2778  			case ir.ONE:
  2779  				return s.newValue1(ssa.OpNot, types.Types[types.TBOOL], c)
  2780  			default:
  2781  				s.Fatalf("ordered complex compare %v", n.Op())
  2782  			}
  2783  		}
  2784  
  2785  		// Convert OGE and OGT into OLE and OLT.
  2786  		op := n.Op()
  2787  		switch op {
  2788  		case ir.OGE:
  2789  			op, a, b = ir.OLE, b, a
  2790  		case ir.OGT:
  2791  			op, a, b = ir.OLT, b, a
  2792  		}
  2793  		if n.X.Type().IsFloat() {
  2794  			// float comparison
  2795  			return s.newValueOrSfCall2(s.ssaOp(op, n.X.Type()), types.Types[types.TBOOL], a, b)
  2796  		}
  2797  		// integer comparison
  2798  		return s.newValue2(s.ssaOp(op, n.X.Type()), types.Types[types.TBOOL], a, b)
  2799  	case ir.OMUL:
  2800  		n := n.(*ir.BinaryExpr)
  2801  		a := s.expr(n.X)
  2802  		b := s.expr(n.Y)
  2803  		if n.Type().IsComplex() {
  2804  			mulop := ssa.OpMul64F
  2805  			addop := ssa.OpAdd64F
  2806  			subop := ssa.OpSub64F
  2807  			pt := types.FloatForComplex(n.Type()) // Could be Float32 or Float64
  2808  			wt := types.Types[types.TFLOAT64]     // Compute in Float64 to minimize cancellation error
  2809  
  2810  			areal := s.newValue1(ssa.OpComplexReal, pt, a)
  2811  			breal := s.newValue1(ssa.OpComplexReal, pt, b)
  2812  			aimag := s.newValue1(ssa.OpComplexImag, pt, a)
  2813  			bimag := s.newValue1(ssa.OpComplexImag, pt, b)
  2814  
  2815  			if pt != wt { // Widen for calculation
  2816  				areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
  2817  				breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
  2818  				aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
  2819  				bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
  2820  			}
  2821  
  2822  			xreal := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
  2823  			ximag := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, bimag), s.newValueOrSfCall2(mulop, wt, aimag, breal))
  2824  
  2825  			if pt != wt { // Narrow to store back
  2826  				xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
  2827  				ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
  2828  			}
  2829  
  2830  			return s.newValue2(ssa.OpComplexMake, n.Type(), xreal, ximag)
  2831  		}
  2832  
  2833  		if n.Type().IsFloat() {
  2834  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  2835  		}
  2836  
  2837  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  2838  
  2839  	case ir.ODIV:
  2840  		n := n.(*ir.BinaryExpr)
  2841  		a := s.expr(n.X)
  2842  		b := s.expr(n.Y)
  2843  		if n.Type().IsComplex() {
  2844  			// TODO this is not executed because the front-end substitutes a runtime call.
  2845  			// That probably ought to change; with modest optimization the widen/narrow
  2846  			// conversions could all be elided in larger expression trees.
  2847  			mulop := ssa.OpMul64F
  2848  			addop := ssa.OpAdd64F
  2849  			subop := ssa.OpSub64F
  2850  			divop := ssa.OpDiv64F
  2851  			pt := types.FloatForComplex(n.Type()) // Could be Float32 or Float64
  2852  			wt := types.Types[types.TFLOAT64]     // Compute in Float64 to minimize cancellation error
  2853  
  2854  			areal := s.newValue1(ssa.OpComplexReal, pt, a)
  2855  			breal := s.newValue1(ssa.OpComplexReal, pt, b)
  2856  			aimag := s.newValue1(ssa.OpComplexImag, pt, a)
  2857  			bimag := s.newValue1(ssa.OpComplexImag, pt, b)
  2858  
  2859  			if pt != wt { // Widen for calculation
  2860  				areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
  2861  				breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
  2862  				aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
  2863  				bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
  2864  			}
  2865  
  2866  			denom := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, breal, breal), s.newValueOrSfCall2(mulop, wt, bimag, bimag))
  2867  			xreal := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
  2868  			ximag := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, aimag, breal), s.newValueOrSfCall2(mulop, wt, areal, bimag))
  2869  
  2870  			// TODO not sure if this is best done in wide precision or narrow
  2871  			// Double-rounding might be an issue.
  2872  			// Note that the pre-SSA implementation does the entire calculation
  2873  			// in wide format, so wide is compatible.
  2874  			xreal = s.newValueOrSfCall2(divop, wt, xreal, denom)
  2875  			ximag = s.newValueOrSfCall2(divop, wt, ximag, denom)
  2876  
  2877  			if pt != wt { // Narrow to store back
  2878  				xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
  2879  				ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
  2880  			}
  2881  			return s.newValue2(ssa.OpComplexMake, n.Type(), xreal, ximag)
  2882  		}
  2883  		if n.Type().IsFloat() {
  2884  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  2885  		}
  2886  		return s.intDivide(n, a, b)
  2887  	case ir.OMOD:
  2888  		n := n.(*ir.BinaryExpr)
  2889  		a := s.expr(n.X)
  2890  		b := s.expr(n.Y)
  2891  		return s.intDivide(n, a, b)
  2892  	case ir.OADD, ir.OSUB:
  2893  		n := n.(*ir.BinaryExpr)
  2894  		a := s.expr(n.X)
  2895  		b := s.expr(n.Y)
  2896  		if n.Type().IsComplex() {
  2897  			pt := types.FloatForComplex(n.Type())
  2898  			op := s.ssaOp(n.Op(), pt)
  2899  			return s.newValue2(ssa.OpComplexMake, n.Type(),
  2900  				s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b)),
  2901  				s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b)))
  2902  		}
  2903  		if n.Type().IsFloat() {
  2904  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  2905  		}
  2906  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  2907  	case ir.OAND, ir.OOR, ir.OXOR:
  2908  		n := n.(*ir.BinaryExpr)
  2909  		a := s.expr(n.X)
  2910  		b := s.expr(n.Y)
  2911  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  2912  	case ir.OANDNOT:
  2913  		n := n.(*ir.BinaryExpr)
  2914  		a := s.expr(n.X)
  2915  		b := s.expr(n.Y)
  2916  		b = s.newValue1(s.ssaOp(ir.OBITNOT, b.Type), b.Type, b)
  2917  		return s.newValue2(s.ssaOp(ir.OAND, n.Type()), a.Type, a, b)
  2918  	case ir.OLSH, ir.ORSH:
  2919  		n := n.(*ir.BinaryExpr)
  2920  		a := s.expr(n.X)
  2921  		b := s.expr(n.Y)
  2922  		bt := b.Type
  2923  		if bt.IsSigned() {
  2924  			cmp := s.newValue2(s.ssaOp(ir.OLE, bt), types.Types[types.TBOOL], s.zeroVal(bt), b)
  2925  			s.check(cmp, ir.Syms.Panicshift)
  2926  			bt = bt.ToUnsigned()
  2927  		}
  2928  		return s.newValue2(s.ssaShiftOp(n.Op(), n.Type(), bt), a.Type, a, b)
  2929  	case ir.OANDAND, ir.OOROR:
  2930  		// To implement OANDAND (and OOROR), we introduce a
  2931  		// new temporary variable to hold the result. The
  2932  		// variable is associated with the OANDAND node in the
  2933  		// s.vars table (normally variables are only
  2934  		// associated with ONAME nodes). We convert
  2935  		//     A && B
  2936  		// to
  2937  		//     var = A
  2938  		//     if var {
  2939  		//         var = B
  2940  		//     }
  2941  		// Using var in the subsequent block introduces the
  2942  		// necessary phi variable.
  2943  		n := n.(*ir.LogicalExpr)
  2944  		el := s.expr(n.X)
  2945  		s.vars[n] = el
  2946  
  2947  		b := s.endBlock()
  2948  		b.Kind = ssa.BlockIf
  2949  		b.SetControl(el)
  2950  		// In theory, we should set b.Likely here based on context.
  2951  		// However, gc only gives us likeliness hints
  2952  		// in a single place, for plain OIF statements,
  2953  		// and passing around context is finnicky, so don't bother for now.
  2954  
  2955  		bRight := s.f.NewBlock(ssa.BlockPlain)
  2956  		bResult := s.f.NewBlock(ssa.BlockPlain)
  2957  		if n.Op() == ir.OANDAND {
  2958  			b.AddEdgeTo(bRight)
  2959  			b.AddEdgeTo(bResult)
  2960  		} else if n.Op() == ir.OOROR {
  2961  			b.AddEdgeTo(bResult)
  2962  			b.AddEdgeTo(bRight)
  2963  		}
  2964  
  2965  		s.startBlock(bRight)
  2966  		er := s.expr(n.Y)
  2967  		s.vars[n] = er
  2968  
  2969  		b = s.endBlock()
  2970  		b.AddEdgeTo(bResult)
  2971  
  2972  		s.startBlock(bResult)
  2973  		return s.variable(n, types.Types[types.TBOOL])
  2974  	case ir.OCOMPLEX:
  2975  		n := n.(*ir.BinaryExpr)
  2976  		r := s.expr(n.X)
  2977  		i := s.expr(n.Y)
  2978  		return s.newValue2(ssa.OpComplexMake, n.Type(), r, i)
  2979  
  2980  	// unary ops
  2981  	case ir.ONEG:
  2982  		n := n.(*ir.UnaryExpr)
  2983  		a := s.expr(n.X)
  2984  		if n.Type().IsComplex() {
  2985  			tp := types.FloatForComplex(n.Type())
  2986  			negop := s.ssaOp(n.Op(), tp)
  2987  			return s.newValue2(ssa.OpComplexMake, n.Type(),
  2988  				s.newValue1(negop, tp, s.newValue1(ssa.OpComplexReal, tp, a)),
  2989  				s.newValue1(negop, tp, s.newValue1(ssa.OpComplexImag, tp, a)))
  2990  		}
  2991  		return s.newValue1(s.ssaOp(n.Op(), n.Type()), a.Type, a)
  2992  	case ir.ONOT, ir.OBITNOT:
  2993  		n := n.(*ir.UnaryExpr)
  2994  		a := s.expr(n.X)
  2995  		return s.newValue1(s.ssaOp(n.Op(), n.Type()), a.Type, a)
  2996  	case ir.OIMAG, ir.OREAL:
  2997  		n := n.(*ir.UnaryExpr)
  2998  		a := s.expr(n.X)
  2999  		return s.newValue1(s.ssaOp(n.Op(), n.X.Type()), n.Type(), a)
  3000  	case ir.OPLUS:
  3001  		n := n.(*ir.UnaryExpr)
  3002  		return s.expr(n.X)
  3003  
  3004  	case ir.OADDR:
  3005  		n := n.(*ir.AddrExpr)
  3006  		return s.addr(n.X)
  3007  
  3008  	case ir.ORESULT:
  3009  		n := n.(*ir.ResultExpr)
  3010  		if s.prevCall == nil || s.prevCall.Op != ssa.OpStaticLECall && s.prevCall.Op != ssa.OpInterLECall && s.prevCall.Op != ssa.OpClosureLECall {
  3011  			panic("Expected to see a previous call")
  3012  		}
  3013  		which := n.Index
  3014  		if which == -1 {
  3015  			panic(fmt.Errorf("ORESULT %v does not match call %s", n, s.prevCall))
  3016  		}
  3017  		return s.resultOfCall(s.prevCall, which, n.Type())
  3018  
  3019  	case ir.ODEREF:
  3020  		n := n.(*ir.StarExpr)
  3021  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  3022  		return s.load(n.Type(), p)
  3023  
  3024  	case ir.ODOT:
  3025  		n := n.(*ir.SelectorExpr)
  3026  		if n.X.Op() == ir.OSTRUCTLIT {
  3027  			// All literals with nonzero fields have already been
  3028  			// rewritten during walk. Any that remain are just T{}
  3029  			// or equivalents. Use the zero value.
  3030  			if !ir.IsZero(n.X) {
  3031  				s.Fatalf("literal with nonzero value in SSA: %v", n.X)
  3032  			}
  3033  			return s.zeroVal(n.Type())
  3034  		}
  3035  		// If n is addressable and can't be represented in
  3036  		// SSA, then load just the selected field. This
  3037  		// prevents false memory dependencies in race/msan/asan
  3038  		// instrumentation.
  3039  		if ir.IsAddressable(n) && !s.canSSA(n) {
  3040  			p := s.addr(n)
  3041  			return s.load(n.Type(), p)
  3042  		}
  3043  		v := s.expr(n.X)
  3044  		return s.newValue1I(ssa.OpStructSelect, n.Type(), int64(fieldIdx(n)), v)
  3045  
  3046  	case ir.ODOTPTR:
  3047  		n := n.(*ir.SelectorExpr)
  3048  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  3049  		p = s.newValue1I(ssa.OpOffPtr, types.NewPtr(n.Type()), n.Offset(), p)
  3050  		return s.load(n.Type(), p)
  3051  
  3052  	case ir.OINDEX:
  3053  		n := n.(*ir.IndexExpr)
  3054  		switch {
  3055  		case n.X.Type().IsString():
  3056  			if n.Bounded() && ir.IsConst(n.X, constant.String) && ir.IsConst(n.Index, constant.Int) {
  3057  				// Replace "abc"[1] with 'b'.
  3058  				// Delayed until now because "abc"[1] is not an ideal constant.
  3059  				// See test/fixedbugs/issue11370.go.
  3060  				return s.newValue0I(ssa.OpConst8, types.Types[types.TUINT8], int64(int8(ir.StringVal(n.X)[ir.Int64Val(n.Index)])))
  3061  			}
  3062  			a := s.expr(n.X)
  3063  			i := s.expr(n.Index)
  3064  			len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], a)
  3065  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  3066  			ptrtyp := s.f.Config.Types.BytePtr
  3067  			ptr := s.newValue1(ssa.OpStringPtr, ptrtyp, a)
  3068  			if ir.IsConst(n.Index, constant.Int) {
  3069  				ptr = s.newValue1I(ssa.OpOffPtr, ptrtyp, ir.Int64Val(n.Index), ptr)
  3070  			} else {
  3071  				ptr = s.newValue2(ssa.OpAddPtr, ptrtyp, ptr, i)
  3072  			}
  3073  			return s.load(types.Types[types.TUINT8], ptr)
  3074  		case n.X.Type().IsSlice():
  3075  			p := s.addr(n)
  3076  			return s.load(n.X.Type().Elem(), p)
  3077  		case n.X.Type().IsArray():
  3078  			if TypeOK(n.X.Type()) {
  3079  				// SSA can handle arrays of length at most 1.
  3080  				bound := n.X.Type().NumElem()
  3081  				a := s.expr(n.X)
  3082  				i := s.expr(n.Index)
  3083  				if bound == 0 {
  3084  					// Bounds check will never succeed.  Might as well
  3085  					// use constants for the bounds check.
  3086  					z := s.constInt(types.Types[types.TINT], 0)
  3087  					s.boundsCheck(z, z, ssa.BoundsIndex, false)
  3088  					// The return value won't be live, return junk.
  3089  					// But not quite junk, in case bounds checks are turned off. See issue 48092.
  3090  					return s.zeroVal(n.Type())
  3091  				}
  3092  				len := s.constInt(types.Types[types.TINT], bound)
  3093  				s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded()) // checks i == 0
  3094  				return s.newValue1I(ssa.OpArraySelect, n.Type(), 0, a)
  3095  			}
  3096  			p := s.addr(n)
  3097  			return s.load(n.X.Type().Elem(), p)
  3098  		default:
  3099  			s.Fatalf("bad type for index %v", n.X.Type())
  3100  			return nil
  3101  		}
  3102  
  3103  	case ir.OLEN, ir.OCAP:
  3104  		n := n.(*ir.UnaryExpr)
  3105  		switch {
  3106  		case n.X.Type().IsSlice():
  3107  			op := ssa.OpSliceLen
  3108  			if n.Op() == ir.OCAP {
  3109  				op = ssa.OpSliceCap
  3110  			}
  3111  			return s.newValue1(op, types.Types[types.TINT], s.expr(n.X))
  3112  		case n.X.Type().IsString(): // string; not reachable for OCAP
  3113  			return s.newValue1(ssa.OpStringLen, types.Types[types.TINT], s.expr(n.X))
  3114  		case n.X.Type().IsMap(), n.X.Type().IsChan():
  3115  			return s.referenceTypeBuiltin(n, s.expr(n.X))
  3116  		default: // array
  3117  			return s.constInt(types.Types[types.TINT], n.X.Type().NumElem())
  3118  		}
  3119  
  3120  	case ir.OSPTR:
  3121  		n := n.(*ir.UnaryExpr)
  3122  		a := s.expr(n.X)
  3123  		if n.X.Type().IsSlice() {
  3124  			return s.newValue1(ssa.OpSlicePtr, n.Type(), a)
  3125  		} else {
  3126  			return s.newValue1(ssa.OpStringPtr, n.Type(), a)
  3127  		}
  3128  
  3129  	case ir.OITAB:
  3130  		n := n.(*ir.UnaryExpr)
  3131  		a := s.expr(n.X)
  3132  		return s.newValue1(ssa.OpITab, n.Type(), a)
  3133  
  3134  	case ir.OIDATA:
  3135  		n := n.(*ir.UnaryExpr)
  3136  		a := s.expr(n.X)
  3137  		return s.newValue1(ssa.OpIData, n.Type(), a)
  3138  
  3139  	case ir.OEFACE:
  3140  		n := n.(*ir.BinaryExpr)
  3141  		tab := s.expr(n.X)
  3142  		data := s.expr(n.Y)
  3143  		return s.newValue2(ssa.OpIMake, n.Type(), tab, data)
  3144  
  3145  	case ir.OSLICEHEADER:
  3146  		n := n.(*ir.SliceHeaderExpr)
  3147  		p := s.expr(n.Ptr)
  3148  		l := s.expr(n.Len)
  3149  		c := s.expr(n.Cap)
  3150  		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3151  
  3152  	case ir.OSLICE, ir.OSLICEARR, ir.OSLICE3, ir.OSLICE3ARR:
  3153  		n := n.(*ir.SliceExpr)
  3154  		check := s.checkPtrEnabled && n.Op() == ir.OSLICE3ARR && n.X.Op() == ir.OCONVNOP && n.X.(*ir.ConvExpr).X.Type().IsUnsafePtr()
  3155  		v := s.exprCheckPtr(n.X, !check)
  3156  		var i, j, k *ssa.Value
  3157  		if n.Low != nil {
  3158  			i = s.expr(n.Low)
  3159  		}
  3160  		if n.High != nil {
  3161  			j = s.expr(n.High)
  3162  		}
  3163  		if n.Max != nil {
  3164  			k = s.expr(n.Max)
  3165  		}
  3166  		p, l, c := s.slice(v, i, j, k, n.Bounded())
  3167  		if check {
  3168  			// Emit checkptr instrumentation after bound check to prevent false positive, see #46938.
  3169  			s.checkPtrAlignment(n.X.(*ir.ConvExpr), v, s.conv(n.Max, k, k.Type, types.Types[types.TUINTPTR]))
  3170  		}
  3171  		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3172  
  3173  	case ir.OSLICESTR:
  3174  		n := n.(*ir.SliceExpr)
  3175  		v := s.expr(n.X)
  3176  		var i, j *ssa.Value
  3177  		if n.Low != nil {
  3178  			i = s.expr(n.Low)
  3179  		}
  3180  		if n.High != nil {
  3181  			j = s.expr(n.High)
  3182  		}
  3183  		p, l, _ := s.slice(v, i, j, nil, n.Bounded())
  3184  		return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
  3185  
  3186  	case ir.OSLICE2ARRPTR:
  3187  		// if arrlen > slice.len {
  3188  		//   panic(...)
  3189  		// }
  3190  		// slice.ptr
  3191  		n := n.(*ir.ConvExpr)
  3192  		v := s.expr(n.X)
  3193  		arrlen := s.constInt(types.Types[types.TINT], n.Type().Elem().NumElem())
  3194  		cap := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
  3195  		s.boundsCheck(arrlen, cap, ssa.BoundsConvert, false)
  3196  		return s.newValue1(ssa.OpSlicePtrUnchecked, n.Type(), v)
  3197  
  3198  	case ir.OCALLFUNC:
  3199  		n := n.(*ir.CallExpr)
  3200  		if ir.IsIntrinsicCall(n) {
  3201  			return s.intrinsicCall(n)
  3202  		}
  3203  		fallthrough
  3204  
  3205  	case ir.OCALLINTER:
  3206  		n := n.(*ir.CallExpr)
  3207  		return s.callResult(n, callNormal)
  3208  
  3209  	case ir.OGETG:
  3210  		n := n.(*ir.CallExpr)
  3211  		return s.newValue1(ssa.OpGetG, n.Type(), s.mem())
  3212  
  3213  	case ir.OGETCALLERPC:
  3214  		n := n.(*ir.CallExpr)
  3215  		return s.newValue0(ssa.OpGetCallerPC, n.Type())
  3216  
  3217  	case ir.OGETCALLERSP:
  3218  		n := n.(*ir.CallExpr)
  3219  		return s.newValue0(ssa.OpGetCallerSP, n.Type())
  3220  
  3221  	case ir.OAPPEND:
  3222  		return s.append(n.(*ir.CallExpr), false)
  3223  
  3224  	case ir.OSTRUCTLIT, ir.OARRAYLIT:
  3225  		// All literals with nonzero fields have already been
  3226  		// rewritten during walk. Any that remain are just T{}
  3227  		// or equivalents. Use the zero value.
  3228  		n := n.(*ir.CompLitExpr)
  3229  		if !ir.IsZero(n) {
  3230  			s.Fatalf("literal with nonzero value in SSA: %v", n)
  3231  		}
  3232  		return s.zeroVal(n.Type())
  3233  
  3234  	case ir.ONEW:
  3235  		n := n.(*ir.UnaryExpr)
  3236  		return s.newObject(n.Type().Elem())
  3237  
  3238  	case ir.OUNSAFEADD:
  3239  		n := n.(*ir.BinaryExpr)
  3240  		ptr := s.expr(n.X)
  3241  		len := s.expr(n.Y)
  3242  
  3243  		// Force len to uintptr to prevent misuse of garbage bits in the
  3244  		// upper part of the register (#48536).
  3245  		len = s.conv(n, len, len.Type, types.Types[types.TUINTPTR])
  3246  
  3247  		return s.newValue2(ssa.OpAddPtr, n.Type(), ptr, len)
  3248  
  3249  	default:
  3250  		s.Fatalf("unhandled expr %v", n.Op())
  3251  		return nil
  3252  	}
  3253  }
  3254  
  3255  func (s *state) resultOfCall(c *ssa.Value, which int64, t *types.Type) *ssa.Value {
  3256  	aux := c.Aux.(*ssa.AuxCall)
  3257  	pa := aux.ParamAssignmentForResult(which)
  3258  	// TODO(register args) determine if in-memory TypeOK is better loaded early from SelectNAddr or later when SelectN is expanded.
  3259  	// SelectN is better for pattern-matching and possible call-aware analysis we might want to do in the future.
  3260  	if len(pa.Registers) == 0 && !TypeOK(t) {
  3261  		addr := s.newValue1I(ssa.OpSelectNAddr, types.NewPtr(t), which, c)
  3262  		return s.rawLoad(t, addr)
  3263  	}
  3264  	return s.newValue1I(ssa.OpSelectN, t, which, c)
  3265  }
  3266  
  3267  func (s *state) resultAddrOfCall(c *ssa.Value, which int64, t *types.Type) *ssa.Value {
  3268  	aux := c.Aux.(*ssa.AuxCall)
  3269  	pa := aux.ParamAssignmentForResult(which)
  3270  	if len(pa.Registers) == 0 {
  3271  		return s.newValue1I(ssa.OpSelectNAddr, types.NewPtr(t), which, c)
  3272  	}
  3273  	_, addr := s.temp(c.Pos, t)
  3274  	rval := s.newValue1I(ssa.OpSelectN, t, which, c)
  3275  	s.vars[memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, addr, rval, s.mem(), false)
  3276  	return addr
  3277  }
  3278  
  3279  // append converts an OAPPEND node to SSA.
  3280  // If inplace is false, it converts the OAPPEND expression n to an ssa.Value,
  3281  // adds it to s, and returns the Value.
  3282  // If inplace is true, it writes the result of the OAPPEND expression n
  3283  // back to the slice being appended to, and returns nil.
  3284  // inplace MUST be set to false if the slice can be SSA'd.
  3285  func (s *state) append(n *ir.CallExpr, inplace bool) *ssa.Value {
  3286  	// If inplace is false, process as expression "append(s, e1, e2, e3)":
  3287  	//
  3288  	// ptr, len, cap := s
  3289  	// newlen := len + 3
  3290  	// if newlen > cap {
  3291  	//     ptr, len, cap = growslice(s, newlen)
  3292  	//     newlen = len + 3 // recalculate to avoid a spill
  3293  	// }
  3294  	// // with write barriers, if needed:
  3295  	// *(ptr+len) = e1
  3296  	// *(ptr+len+1) = e2
  3297  	// *(ptr+len+2) = e3
  3298  	// return makeslice(ptr, newlen, cap)
  3299  	//
  3300  	//
  3301  	// If inplace is true, process as statement "s = append(s, e1, e2, e3)":
  3302  	//
  3303  	// a := &s
  3304  	// ptr, len, cap := s
  3305  	// newlen := len + 3
  3306  	// if uint(newlen) > uint(cap) {
  3307  	//    newptr, len, newcap = growslice(ptr, len, cap, newlen)
  3308  	//    vardef(a)       // if necessary, advise liveness we are writing a new a
  3309  	//    *a.cap = newcap // write before ptr to avoid a spill
  3310  	//    *a.ptr = newptr // with write barrier
  3311  	// }
  3312  	// newlen = len + 3 // recalculate to avoid a spill
  3313  	// *a.len = newlen
  3314  	// // with write barriers, if needed:
  3315  	// *(ptr+len) = e1
  3316  	// *(ptr+len+1) = e2
  3317  	// *(ptr+len+2) = e3
  3318  
  3319  	et := n.Type().Elem()
  3320  	pt := types.NewPtr(et)
  3321  
  3322  	// Evaluate slice
  3323  	sn := n.Args[0] // the slice node is the first in the list
  3324  
  3325  	var slice, addr *ssa.Value
  3326  	if inplace {
  3327  		addr = s.addr(sn)
  3328  		slice = s.load(n.Type(), addr)
  3329  	} else {
  3330  		slice = s.expr(sn)
  3331  	}
  3332  
  3333  	// Allocate new blocks
  3334  	grow := s.f.NewBlock(ssa.BlockPlain)
  3335  	assign := s.f.NewBlock(ssa.BlockPlain)
  3336  
  3337  	// Decide if we need to grow
  3338  	nargs := int64(len(n.Args) - 1)
  3339  	p := s.newValue1(ssa.OpSlicePtr, pt, slice)
  3340  	l := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  3341  	c := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], slice)
  3342  	nl := s.newValue2(s.ssaOp(ir.OADD, types.Types[types.TINT]), types.Types[types.TINT], l, s.constInt(types.Types[types.TINT], nargs))
  3343  
  3344  	cmp := s.newValue2(s.ssaOp(ir.OLT, types.Types[types.TUINT]), types.Types[types.TBOOL], c, nl)
  3345  	s.vars[ptrVar] = p
  3346  
  3347  	if !inplace {
  3348  		s.vars[newlenVar] = nl
  3349  		s.vars[capVar] = c
  3350  	} else {
  3351  		s.vars[lenVar] = l
  3352  	}
  3353  
  3354  	b := s.endBlock()
  3355  	b.Kind = ssa.BlockIf
  3356  	b.Likely = ssa.BranchUnlikely
  3357  	b.SetControl(cmp)
  3358  	b.AddEdgeTo(grow)
  3359  	b.AddEdgeTo(assign)
  3360  
  3361  	// Call growslice
  3362  	s.startBlock(grow)
  3363  	taddr := s.expr(n.X)
  3364  	r := s.rtcall(ir.Syms.Growslice, true, []*types.Type{pt, types.Types[types.TINT], types.Types[types.TINT]}, taddr, p, l, c, nl)
  3365  
  3366  	if inplace {
  3367  		if sn.Op() == ir.ONAME {
  3368  			sn := sn.(*ir.Name)
  3369  			if sn.Class != ir.PEXTERN {
  3370  				// Tell liveness we're about to build a new slice
  3371  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, sn, s.mem())
  3372  			}
  3373  		}
  3374  		capaddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, types.SliceCapOffset, addr)
  3375  		s.store(types.Types[types.TINT], capaddr, r[2])
  3376  		s.store(pt, addr, r[0])
  3377  		// load the value we just stored to avoid having to spill it
  3378  		s.vars[ptrVar] = s.load(pt, addr)
  3379  		s.vars[lenVar] = r[1] // avoid a spill in the fast path
  3380  	} else {
  3381  		s.vars[ptrVar] = r[0]
  3382  		s.vars[newlenVar] = s.newValue2(s.ssaOp(ir.OADD, types.Types[types.TINT]), types.Types[types.TINT], r[1], s.constInt(types.Types[types.TINT], nargs))
  3383  		s.vars[capVar] = r[2]
  3384  	}
  3385  
  3386  	b = s.endBlock()
  3387  	b.AddEdgeTo(assign)
  3388  
  3389  	// assign new elements to slots
  3390  	s.startBlock(assign)
  3391  
  3392  	if inplace {
  3393  		l = s.variable(lenVar, types.Types[types.TINT]) // generates phi for len
  3394  		nl = s.newValue2(s.ssaOp(ir.OADD, types.Types[types.TINT]), types.Types[types.TINT], l, s.constInt(types.Types[types.TINT], nargs))
  3395  		lenaddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, types.SliceLenOffset, addr)
  3396  		s.store(types.Types[types.TINT], lenaddr, nl)
  3397  	}
  3398  
  3399  	// Evaluate args
  3400  	type argRec struct {
  3401  		// if store is true, we're appending the value v.  If false, we're appending the
  3402  		// value at *v.
  3403  		v     *ssa.Value
  3404  		store bool
  3405  	}
  3406  	args := make([]argRec, 0, nargs)
  3407  	for _, n := range n.Args[1:] {
  3408  		if TypeOK(n.Type()) {
  3409  			args = append(args, argRec{v: s.expr(n), store: true})
  3410  		} else {
  3411  			v := s.addr(n)
  3412  			args = append(args, argRec{v: v})
  3413  		}
  3414  	}
  3415  
  3416  	p = s.variable(ptrVar, pt) // generates phi for ptr
  3417  	if !inplace {
  3418  		nl = s.variable(newlenVar, types.Types[types.TINT]) // generates phi for nl
  3419  		c = s.variable(capVar, types.Types[types.TINT])     // generates phi for cap
  3420  	}
  3421  	p2 := s.newValue2(ssa.OpPtrIndex, pt, p, l)
  3422  	for i, arg := range args {
  3423  		addr := s.newValue2(ssa.OpPtrIndex, pt, p2, s.constInt(types.Types[types.TINT], int64(i)))
  3424  		if arg.store {
  3425  			s.storeType(et, addr, arg.v, 0, true)
  3426  		} else {
  3427  			s.move(et, addr, arg.v)
  3428  		}
  3429  	}
  3430  
  3431  	delete(s.vars, ptrVar)
  3432  	if inplace {
  3433  		delete(s.vars, lenVar)
  3434  		return nil
  3435  	}
  3436  	delete(s.vars, newlenVar)
  3437  	delete(s.vars, capVar)
  3438  	// make result
  3439  	return s.newValue3(ssa.OpSliceMake, n.Type(), p, nl, c)
  3440  }
  3441  
  3442  // condBranch evaluates the boolean expression cond and branches to yes
  3443  // if cond is true and no if cond is false.
  3444  // This function is intended to handle && and || better than just calling
  3445  // s.expr(cond) and branching on the result.
  3446  func (s *state) condBranch(cond ir.Node, yes, no *ssa.Block, likely int8) {
  3447  	switch cond.Op() {
  3448  	case ir.OANDAND:
  3449  		cond := cond.(*ir.LogicalExpr)
  3450  		mid := s.f.NewBlock(ssa.BlockPlain)
  3451  		s.stmtList(cond.Init())
  3452  		s.condBranch(cond.X, mid, no, max8(likely, 0))
  3453  		s.startBlock(mid)
  3454  		s.condBranch(cond.Y, yes, no, likely)
  3455  		return
  3456  		// Note: if likely==1, then both recursive calls pass 1.
  3457  		// If likely==-1, then we don't have enough information to decide
  3458  		// whether the first branch is likely or not. So we pass 0 for
  3459  		// the likeliness of the first branch.
  3460  		// TODO: have the frontend give us branch prediction hints for
  3461  		// OANDAND and OOROR nodes (if it ever has such info).
  3462  	case ir.OOROR:
  3463  		cond := cond.(*ir.LogicalExpr)
  3464  		mid := s.f.NewBlock(ssa.BlockPlain)
  3465  		s.stmtList(cond.Init())
  3466  		s.condBranch(cond.X, yes, mid, min8(likely, 0))
  3467  		s.startBlock(mid)
  3468  		s.condBranch(cond.Y, yes, no, likely)
  3469  		return
  3470  		// Note: if likely==-1, then both recursive calls pass -1.
  3471  		// If likely==1, then we don't have enough info to decide
  3472  		// the likelihood of the first branch.
  3473  	case ir.ONOT:
  3474  		cond := cond.(*ir.UnaryExpr)
  3475  		s.stmtList(cond.Init())
  3476  		s.condBranch(cond.X, no, yes, -likely)
  3477  		return
  3478  	case ir.OCONVNOP:
  3479  		cond := cond.(*ir.ConvExpr)
  3480  		s.stmtList(cond.Init())
  3481  		s.condBranch(cond.X, yes, no, likely)
  3482  		return
  3483  	}
  3484  	c := s.expr(cond)
  3485  	b := s.endBlock()
  3486  	b.Kind = ssa.BlockIf
  3487  	b.SetControl(c)
  3488  	b.Likely = ssa.BranchPrediction(likely) // gc and ssa both use -1/0/+1 for likeliness
  3489  	b.AddEdgeTo(yes)
  3490  	b.AddEdgeTo(no)
  3491  }
  3492  
  3493  type skipMask uint8
  3494  
  3495  const (
  3496  	skipPtr skipMask = 1 << iota
  3497  	skipLen
  3498  	skipCap
  3499  )
  3500  
  3501  // assign does left = right.
  3502  // Right has already been evaluated to ssa, left has not.
  3503  // If deref is true, then we do left = *right instead (and right has already been nil-checked).
  3504  // If deref is true and right == nil, just do left = 0.
  3505  // skip indicates assignments (at the top level) that can be avoided.
  3506  func (s *state) assign(left ir.Node, right *ssa.Value, deref bool, skip skipMask) {
  3507  	if left.Op() == ir.ONAME && ir.IsBlank(left) {
  3508  		return
  3509  	}
  3510  	t := left.Type()
  3511  	types.CalcSize(t)
  3512  	if s.canSSA(left) {
  3513  		if deref {
  3514  			s.Fatalf("can SSA LHS %v but not RHS %s", left, right)
  3515  		}
  3516  		if left.Op() == ir.ODOT {
  3517  			// We're assigning to a field of an ssa-able value.
  3518  			// We need to build a new structure with the new value for the
  3519  			// field we're assigning and the old values for the other fields.
  3520  			// For instance:
  3521  			//   type T struct {a, b, c int}
  3522  			//   var T x
  3523  			//   x.b = 5
  3524  			// For the x.b = 5 assignment we want to generate x = T{x.a, 5, x.c}
  3525  
  3526  			// Grab information about the structure type.
  3527  			left := left.(*ir.SelectorExpr)
  3528  			t := left.X.Type()
  3529  			nf := t.NumFields()
  3530  			idx := fieldIdx(left)
  3531  
  3532  			// Grab old value of structure.
  3533  			old := s.expr(left.X)
  3534  
  3535  			// Make new structure.
  3536  			new := s.newValue0(ssa.StructMakeOp(t.NumFields()), t)
  3537  
  3538  			// Add fields as args.
  3539  			for i := 0; i < nf; i++ {
  3540  				if i == idx {
  3541  					new.AddArg(right)
  3542  				} else {
  3543  					new.AddArg(s.newValue1I(ssa.OpStructSelect, t.FieldType(i), int64(i), old))
  3544  				}
  3545  			}
  3546  
  3547  			// Recursively assign the new value we've made to the base of the dot op.
  3548  			s.assign(left.X, new, false, 0)
  3549  			// TODO: do we need to update named values here?
  3550  			return
  3551  		}
  3552  		if left.Op() == ir.OINDEX && left.(*ir.IndexExpr).X.Type().IsArray() {
  3553  			left := left.(*ir.IndexExpr)
  3554  			s.pushLine(left.Pos())
  3555  			defer s.popLine()
  3556  			// We're assigning to an element of an ssa-able array.
  3557  			// a[i] = v
  3558  			t := left.X.Type()
  3559  			n := t.NumElem()
  3560  
  3561  			i := s.expr(left.Index) // index
  3562  			if n == 0 {
  3563  				// The bounds check must fail.  Might as well
  3564  				// ignore the actual index and just use zeros.
  3565  				z := s.constInt(types.Types[types.TINT], 0)
  3566  				s.boundsCheck(z, z, ssa.BoundsIndex, false)
  3567  				return
  3568  			}
  3569  			if n != 1 {
  3570  				s.Fatalf("assigning to non-1-length array")
  3571  			}
  3572  			// Rewrite to a = [1]{v}
  3573  			len := s.constInt(types.Types[types.TINT], 1)
  3574  			s.boundsCheck(i, len, ssa.BoundsIndex, false) // checks i == 0
  3575  			v := s.newValue1(ssa.OpArrayMake1, t, right)
  3576  			s.assign(left.X, v, false, 0)
  3577  			return
  3578  		}
  3579  		left := left.(*ir.Name)
  3580  		// Update variable assignment.
  3581  		s.vars[left] = right
  3582  		s.addNamedValue(left, right)
  3583  		return
  3584  	}
  3585  
  3586  	// If this assignment clobbers an entire local variable, then emit
  3587  	// OpVarDef so liveness analysis knows the variable is redefined.
  3588  	if base, ok := clobberBase(left).(*ir.Name); ok && base.OnStack() && skip == 0 {
  3589  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, base, s.mem(), !ir.IsAutoTmp(base))
  3590  	}
  3591  
  3592  	// Left is not ssa-able. Compute its address.
  3593  	addr := s.addr(left)
  3594  	if ir.IsReflectHeaderDataField(left) {
  3595  		// Package unsafe's documentation says storing pointers into
  3596  		// reflect.SliceHeader and reflect.StringHeader's Data fields
  3597  		// is valid, even though they have type uintptr (#19168).
  3598  		// Mark it pointer type to signal the writebarrier pass to
  3599  		// insert a write barrier.
  3600  		t = types.Types[types.TUNSAFEPTR]
  3601  	}
  3602  	if deref {
  3603  		// Treat as a mem->mem move.
  3604  		if right == nil {
  3605  			s.zero(t, addr)
  3606  		} else {
  3607  			s.move(t, addr, right)
  3608  		}
  3609  		return
  3610  	}
  3611  	// Treat as a store.
  3612  	s.storeType(t, addr, right, skip, !ir.IsAutoTmp(left))
  3613  }
  3614  
  3615  // zeroVal returns the zero value for type t.
  3616  func (s *state) zeroVal(t *types.Type) *ssa.Value {
  3617  	switch {
  3618  	case t.IsInteger():
  3619  		switch t.Size() {
  3620  		case 1:
  3621  			return s.constInt8(t, 0)
  3622  		case 2:
  3623  			return s.constInt16(t, 0)
  3624  		case 4:
  3625  			return s.constInt32(t, 0)
  3626  		case 8:
  3627  			return s.constInt64(t, 0)
  3628  		default:
  3629  			s.Fatalf("bad sized integer type %v", t)
  3630  		}
  3631  	case t.IsFloat():
  3632  		switch t.Size() {
  3633  		case 4:
  3634  			return s.constFloat32(t, 0)
  3635  		case 8:
  3636  			return s.constFloat64(t, 0)
  3637  		default:
  3638  			s.Fatalf("bad sized float type %v", t)
  3639  		}
  3640  	case t.IsComplex():
  3641  		switch t.Size() {
  3642  		case 8:
  3643  			z := s.constFloat32(types.Types[types.TFLOAT32], 0)
  3644  			return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
  3645  		case 16:
  3646  			z := s.constFloat64(types.Types[types.TFLOAT64], 0)
  3647  			return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
  3648  		default:
  3649  			s.Fatalf("bad sized complex type %v", t)
  3650  		}
  3651  
  3652  	case t.IsString():
  3653  		return s.constEmptyString(t)
  3654  	case t.IsPtrShaped():
  3655  		return s.constNil(t)
  3656  	case t.IsBoolean():
  3657  		return s.constBool(false)
  3658  	case t.IsInterface():
  3659  		return s.constInterface(t)
  3660  	case t.IsSlice():
  3661  		return s.constSlice(t)
  3662  	case t.IsStruct():
  3663  		n := t.NumFields()
  3664  		v := s.entryNewValue0(ssa.StructMakeOp(t.NumFields()), t)
  3665  		for i := 0; i < n; i++ {
  3666  			v.AddArg(s.zeroVal(t.FieldType(i)))
  3667  		}
  3668  		return v
  3669  	case t.IsArray():
  3670  		switch t.NumElem() {
  3671  		case 0:
  3672  			return s.entryNewValue0(ssa.OpArrayMake0, t)
  3673  		case 1:
  3674  			return s.entryNewValue1(ssa.OpArrayMake1, t, s.zeroVal(t.Elem()))
  3675  		}
  3676  	}
  3677  	s.Fatalf("zero for type %v not implemented", t)
  3678  	return nil
  3679  }
  3680  
  3681  type callKind int8
  3682  
  3683  const (
  3684  	callNormal callKind = iota
  3685  	callDefer
  3686  	callDeferStack
  3687  	callGo
  3688  	callTail
  3689  )
  3690  
  3691  type sfRtCallDef struct {
  3692  	rtfn  *obj.LSym
  3693  	rtype types.Kind
  3694  }
  3695  
  3696  var softFloatOps map[ssa.Op]sfRtCallDef
  3697  
  3698  func softfloatInit() {
  3699  	// Some of these operations get transformed by sfcall.
  3700  	softFloatOps = map[ssa.Op]sfRtCallDef{
  3701  		ssa.OpAdd32F: sfRtCallDef{typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
  3702  		ssa.OpAdd64F: sfRtCallDef{typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
  3703  		ssa.OpSub32F: sfRtCallDef{typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
  3704  		ssa.OpSub64F: sfRtCallDef{typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
  3705  		ssa.OpMul32F: sfRtCallDef{typecheck.LookupRuntimeFunc("fmul32"), types.TFLOAT32},
  3706  		ssa.OpMul64F: sfRtCallDef{typecheck.LookupRuntimeFunc("fmul64"), types.TFLOAT64},
  3707  		ssa.OpDiv32F: sfRtCallDef{typecheck.LookupRuntimeFunc("fdiv32"), types.TFLOAT32},
  3708  		ssa.OpDiv64F: sfRtCallDef{typecheck.LookupRuntimeFunc("fdiv64"), types.TFLOAT64},
  3709  
  3710  		ssa.OpEq64F:   sfRtCallDef{typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
  3711  		ssa.OpEq32F:   sfRtCallDef{typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
  3712  		ssa.OpNeq64F:  sfRtCallDef{typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
  3713  		ssa.OpNeq32F:  sfRtCallDef{typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
  3714  		ssa.OpLess64F: sfRtCallDef{typecheck.LookupRuntimeFunc("fgt64"), types.TBOOL},
  3715  		ssa.OpLess32F: sfRtCallDef{typecheck.LookupRuntimeFunc("fgt32"), types.TBOOL},
  3716  		ssa.OpLeq64F:  sfRtCallDef{typecheck.LookupRuntimeFunc("fge64"), types.TBOOL},
  3717  		ssa.OpLeq32F:  sfRtCallDef{typecheck.LookupRuntimeFunc("fge32"), types.TBOOL},
  3718  
  3719  		ssa.OpCvt32to32F:  sfRtCallDef{typecheck.LookupRuntimeFunc("fint32to32"), types.TFLOAT32},
  3720  		ssa.OpCvt32Fto32:  sfRtCallDef{typecheck.LookupRuntimeFunc("f32toint32"), types.TINT32},
  3721  		ssa.OpCvt64to32F:  sfRtCallDef{typecheck.LookupRuntimeFunc("fint64to32"), types.TFLOAT32},
  3722  		ssa.OpCvt32Fto64:  sfRtCallDef{typecheck.LookupRuntimeFunc("f32toint64"), types.TINT64},
  3723  		ssa.OpCvt64Uto32F: sfRtCallDef{typecheck.LookupRuntimeFunc("fuint64to32"), types.TFLOAT32},
  3724  		ssa.OpCvt32Fto64U: sfRtCallDef{typecheck.LookupRuntimeFunc("f32touint64"), types.TUINT64},
  3725  		ssa.OpCvt32to64F:  sfRtCallDef{typecheck.LookupRuntimeFunc("fint32to64"), types.TFLOAT64},
  3726  		ssa.OpCvt64Fto32:  sfRtCallDef{typecheck.LookupRuntimeFunc("f64toint32"), types.TINT32},
  3727  		ssa.OpCvt64to64F:  sfRtCallDef{typecheck.LookupRuntimeFunc("fint64to64"), types.TFLOAT64},
  3728  		ssa.OpCvt64Fto64:  sfRtCallDef{typecheck.LookupRuntimeFunc("f64toint64"), types.TINT64},
  3729  		ssa.OpCvt64Uto64F: sfRtCallDef{typecheck.LookupRuntimeFunc("fuint64to64"), types.TFLOAT64},
  3730  		ssa.OpCvt64Fto64U: sfRtCallDef{typecheck.LookupRuntimeFunc("f64touint64"), types.TUINT64},
  3731  		ssa.OpCvt32Fto64F: sfRtCallDef{typecheck.LookupRuntimeFunc("f32to64"), types.TFLOAT64},
  3732  		ssa.OpCvt64Fto32F: sfRtCallDef{typecheck.LookupRuntimeFunc("f64to32"), types.TFLOAT32},
  3733  	}
  3734  }
  3735  
  3736  // TODO: do not emit sfcall if operation can be optimized to constant in later
  3737  // opt phase
  3738  func (s *state) sfcall(op ssa.Op, args ...*ssa.Value) (*ssa.Value, bool) {
  3739  	f2i := func(t *types.Type) *types.Type {
  3740  		switch t.Kind() {
  3741  		case types.TFLOAT32:
  3742  			return types.Types[types.TUINT32]
  3743  		case types.TFLOAT64:
  3744  			return types.Types[types.TUINT64]
  3745  		}
  3746  		return t
  3747  	}
  3748  
  3749  	if callDef, ok := softFloatOps[op]; ok {
  3750  		switch op {
  3751  		case ssa.OpLess32F,
  3752  			ssa.OpLess64F,
  3753  			ssa.OpLeq32F,
  3754  			ssa.OpLeq64F:
  3755  			args[0], args[1] = args[1], args[0]
  3756  		case ssa.OpSub32F,
  3757  			ssa.OpSub64F:
  3758  			args[1] = s.newValue1(s.ssaOp(ir.ONEG, types.Types[callDef.rtype]), args[1].Type, args[1])
  3759  		}
  3760  
  3761  		// runtime functions take uints for floats and returns uints.
  3762  		// Convert to uints so we use the right calling convention.
  3763  		for i, a := range args {
  3764  			if a.Type.IsFloat() {
  3765  				args[i] = s.newValue1(ssa.OpCopy, f2i(a.Type), a)
  3766  			}
  3767  		}
  3768  
  3769  		rt := types.Types[callDef.rtype]
  3770  		result := s.rtcall(callDef.rtfn, true, []*types.Type{f2i(rt)}, args...)[0]
  3771  		if rt.IsFloat() {
  3772  			result = s.newValue1(ssa.OpCopy, rt, result)
  3773  		}
  3774  		if op == ssa.OpNeq32F || op == ssa.OpNeq64F {
  3775  			result = s.newValue1(ssa.OpNot, result.Type, result)
  3776  		}
  3777  		return result, true
  3778  	}
  3779  	return nil, false
  3780  }
  3781  
  3782  var intrinsics map[intrinsicKey]intrinsicBuilder
  3783  
  3784  // An intrinsicBuilder converts a call node n into an ssa value that
  3785  // implements that call as an intrinsic. args is a list of arguments to the func.
  3786  type intrinsicBuilder func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value
  3787  
  3788  type intrinsicKey struct {
  3789  	arch *sys.Arch
  3790  	pkg  string
  3791  	fn   string
  3792  }
  3793  
  3794  func InitTables() {
  3795  	intrinsics = map[intrinsicKey]intrinsicBuilder{}
  3796  
  3797  	var all []*sys.Arch
  3798  	var p4 []*sys.Arch
  3799  	var p8 []*sys.Arch
  3800  	var lwatomics []*sys.Arch
  3801  	for _, a := range &sys.Archs {
  3802  		all = append(all, a)
  3803  		if a.PtrSize == 4 {
  3804  			p4 = append(p4, a)
  3805  		} else {
  3806  			p8 = append(p8, a)
  3807  		}
  3808  		if a.Family != sys.PPC64 {
  3809  			lwatomics = append(lwatomics, a)
  3810  		}
  3811  	}
  3812  
  3813  	// add adds the intrinsic b for pkg.fn for the given list of architectures.
  3814  	add := func(pkg, fn string, b intrinsicBuilder, archs ...*sys.Arch) {
  3815  		for _, a := range archs {
  3816  			intrinsics[intrinsicKey{a, pkg, fn}] = b
  3817  		}
  3818  	}
  3819  	// addF does the same as add but operates on architecture families.
  3820  	addF := func(pkg, fn string, b intrinsicBuilder, archFamilies ...sys.ArchFamily) {
  3821  		m := 0
  3822  		for _, f := range archFamilies {
  3823  			if f >= 32 {
  3824  				panic("too many architecture families")
  3825  			}
  3826  			m |= 1 << uint(f)
  3827  		}
  3828  		for _, a := range all {
  3829  			if m>>uint(a.Family)&1 != 0 {
  3830  				intrinsics[intrinsicKey{a, pkg, fn}] = b
  3831  			}
  3832  		}
  3833  	}
  3834  	// alias defines pkg.fn = pkg2.fn2 for all architectures in archs for which pkg2.fn2 exists.
  3835  	alias := func(pkg, fn, pkg2, fn2 string, archs ...*sys.Arch) {
  3836  		aliased := false
  3837  		for _, a := range archs {
  3838  			if b, ok := intrinsics[intrinsicKey{a, pkg2, fn2}]; ok {
  3839  				intrinsics[intrinsicKey{a, pkg, fn}] = b
  3840  				aliased = true
  3841  			}
  3842  		}
  3843  		if !aliased {
  3844  			panic(fmt.Sprintf("attempted to alias undefined intrinsic: %s.%s", pkg, fn))
  3845  		}
  3846  	}
  3847  
  3848  	/******** runtime ********/
  3849  	if !base.Flag.Cfg.Instrumenting {
  3850  		add("runtime", "slicebytetostringtmp",
  3851  			func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3852  				// Compiler frontend optimizations emit OBYTES2STRTMP nodes
  3853  				// for the backend instead of slicebytetostringtmp calls
  3854  				// when not instrumenting.
  3855  				return s.newValue2(ssa.OpStringMake, n.Type(), args[0], args[1])
  3856  			},
  3857  			all...)
  3858  	}
  3859  	addF("runtime/internal/math", "MulUintptr",
  3860  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3861  			if s.config.PtrSize == 4 {
  3862  				return s.newValue2(ssa.OpMul32uover, types.NewTuple(types.Types[types.TUINT], types.Types[types.TUINT]), args[0], args[1])
  3863  			}
  3864  			return s.newValue2(ssa.OpMul64uover, types.NewTuple(types.Types[types.TUINT], types.Types[types.TUINT]), args[0], args[1])
  3865  		},
  3866  		sys.AMD64, sys.I386, sys.MIPS64, sys.RISCV64)
  3867  	add("runtime", "KeepAlive",
  3868  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3869  			data := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, args[0])
  3870  			s.vars[memVar] = s.newValue2(ssa.OpKeepAlive, types.TypeMem, data, s.mem())
  3871  			return nil
  3872  		},
  3873  		all...)
  3874  	add("runtime", "getclosureptr",
  3875  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3876  			return s.newValue0(ssa.OpGetClosurePtr, s.f.Config.Types.Uintptr)
  3877  		},
  3878  		all...)
  3879  
  3880  	add("runtime", "getcallerpc",
  3881  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3882  			return s.newValue0(ssa.OpGetCallerPC, s.f.Config.Types.Uintptr)
  3883  		},
  3884  		all...)
  3885  
  3886  	add("runtime", "getcallersp",
  3887  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3888  			return s.newValue0(ssa.OpGetCallerSP, s.f.Config.Types.Uintptr)
  3889  		},
  3890  		all...)
  3891  
  3892  	addF("runtime", "publicationBarrier",
  3893  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3894  			s.vars[memVar] = s.newValue1(ssa.OpPubBarrier, types.TypeMem, s.mem())
  3895  			return nil
  3896  		},
  3897  		sys.ARM64)
  3898  
  3899  	/******** runtime/internal/sys ********/
  3900  	addF("runtime/internal/sys", "Ctz32",
  3901  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3902  			return s.newValue1(ssa.OpCtz32, types.Types[types.TINT], args[0])
  3903  		},
  3904  		sys.AMD64, sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64)
  3905  	addF("runtime/internal/sys", "Ctz64",
  3906  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3907  			return s.newValue1(ssa.OpCtz64, types.Types[types.TINT], args[0])
  3908  		},
  3909  		sys.AMD64, sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64)
  3910  	addF("runtime/internal/sys", "Bswap32",
  3911  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3912  			return s.newValue1(ssa.OpBswap32, types.Types[types.TUINT32], args[0])
  3913  		},
  3914  		sys.AMD64, sys.ARM64, sys.ARM, sys.S390X)
  3915  	addF("runtime/internal/sys", "Bswap64",
  3916  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3917  			return s.newValue1(ssa.OpBswap64, types.Types[types.TUINT64], args[0])
  3918  		},
  3919  		sys.AMD64, sys.ARM64, sys.ARM, sys.S390X)
  3920  
  3921  	/****** Prefetch ******/
  3922  	makePrefetchFunc := func(op ssa.Op) func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3923  		return func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3924  			s.vars[memVar] = s.newValue2(op, types.TypeMem, args[0], s.mem())
  3925  			return nil
  3926  		}
  3927  	}
  3928  
  3929  	// Make Prefetch intrinsics for supported platforms
  3930  	// On the unsupported platforms stub function will be eliminated
  3931  	addF("runtime/internal/sys", "Prefetch", makePrefetchFunc(ssa.OpPrefetchCache),
  3932  		sys.AMD64, sys.ARM64, sys.PPC64)
  3933  	addF("runtime/internal/sys", "PrefetchStreamed", makePrefetchFunc(ssa.OpPrefetchCacheStreamed),
  3934  		sys.AMD64, sys.ARM64, sys.PPC64)
  3935  
  3936  	/******** runtime/internal/atomic ********/
  3937  	addF("runtime/internal/atomic", "Load",
  3938  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3939  			v := s.newValue2(ssa.OpAtomicLoad32, types.NewTuple(types.Types[types.TUINT32], types.TypeMem), args[0], s.mem())
  3940  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  3941  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT32], v)
  3942  		},
  3943  		sys.AMD64, sys.ARM64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  3944  	addF("runtime/internal/atomic", "Load8",
  3945  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3946  			v := s.newValue2(ssa.OpAtomicLoad8, types.NewTuple(types.Types[types.TUINT8], types.TypeMem), args[0], s.mem())
  3947  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  3948  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT8], v)
  3949  		},
  3950  		sys.AMD64, sys.ARM64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  3951  	addF("runtime/internal/atomic", "Load64",
  3952  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3953  			v := s.newValue2(ssa.OpAtomicLoad64, types.NewTuple(types.Types[types.TUINT64], types.TypeMem), args[0], s.mem())
  3954  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  3955  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT64], v)
  3956  		},
  3957  		sys.AMD64, sys.ARM64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  3958  	addF("runtime/internal/atomic", "LoadAcq",
  3959  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3960  			v := s.newValue2(ssa.OpAtomicLoadAcq32, types.NewTuple(types.Types[types.TUINT32], types.TypeMem), args[0], s.mem())
  3961  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  3962  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT32], v)
  3963  		},
  3964  		sys.PPC64, sys.S390X)
  3965  	addF("runtime/internal/atomic", "LoadAcq64",
  3966  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3967  			v := s.newValue2(ssa.OpAtomicLoadAcq64, types.NewTuple(types.Types[types.TUINT64], types.TypeMem), args[0], s.mem())
  3968  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  3969  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT64], v)
  3970  		},
  3971  		sys.PPC64)
  3972  	addF("runtime/internal/atomic", "Loadp",
  3973  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3974  			v := s.newValue2(ssa.OpAtomicLoadPtr, types.NewTuple(s.f.Config.Types.BytePtr, types.TypeMem), args[0], s.mem())
  3975  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  3976  			return s.newValue1(ssa.OpSelect0, s.f.Config.Types.BytePtr, v)
  3977  		},
  3978  		sys.AMD64, sys.ARM64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  3979  
  3980  	addF("runtime/internal/atomic", "Store",
  3981  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3982  			s.vars[memVar] = s.newValue3(ssa.OpAtomicStore32, types.TypeMem, args[0], args[1], s.mem())
  3983  			return nil
  3984  		},
  3985  		sys.AMD64, sys.ARM64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  3986  	addF("runtime/internal/atomic", "Store8",
  3987  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3988  			s.vars[memVar] = s.newValue3(ssa.OpAtomicStore8, types.TypeMem, args[0], args[1], s.mem())
  3989  			return nil
  3990  		},
  3991  		sys.AMD64, sys.ARM64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  3992  	addF("runtime/internal/atomic", "Store64",
  3993  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  3994  			s.vars[memVar] = s.newValue3(ssa.OpAtomicStore64, types.TypeMem, args[0], args[1], s.mem())
  3995  			return nil
  3996  		},
  3997  		sys.AMD64, sys.ARM64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  3998  	addF("runtime/internal/atomic", "StorepNoWB",
  3999  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4000  			s.vars[memVar] = s.newValue3(ssa.OpAtomicStorePtrNoWB, types.TypeMem, args[0], args[1], s.mem())
  4001  			return nil
  4002  		},
  4003  		sys.AMD64, sys.ARM64, sys.MIPS, sys.MIPS64, sys.RISCV64, sys.S390X)
  4004  	addF("runtime/internal/atomic", "StoreRel",
  4005  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4006  			s.vars[memVar] = s.newValue3(ssa.OpAtomicStoreRel32, types.TypeMem, args[0], args[1], s.mem())
  4007  			return nil
  4008  		},
  4009  		sys.PPC64, sys.S390X)
  4010  	addF("runtime/internal/atomic", "StoreRel64",
  4011  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4012  			s.vars[memVar] = s.newValue3(ssa.OpAtomicStoreRel64, types.TypeMem, args[0], args[1], s.mem())
  4013  			return nil
  4014  		},
  4015  		sys.PPC64)
  4016  
  4017  	addF("runtime/internal/atomic", "Xchg",
  4018  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4019  			v := s.newValue3(ssa.OpAtomicExchange32, types.NewTuple(types.Types[types.TUINT32], types.TypeMem), args[0], args[1], s.mem())
  4020  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4021  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT32], v)
  4022  		},
  4023  		sys.AMD64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4024  	addF("runtime/internal/atomic", "Xchg64",
  4025  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4026  			v := s.newValue3(ssa.OpAtomicExchange64, types.NewTuple(types.Types[types.TUINT64], types.TypeMem), args[0], args[1], s.mem())
  4027  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4028  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT64], v)
  4029  		},
  4030  		sys.AMD64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4031  
  4032  	type atomicOpEmitter func(s *state, n *ir.CallExpr, args []*ssa.Value, op ssa.Op, typ types.Kind)
  4033  
  4034  	makeAtomicGuardedIntrinsicARM64 := func(op0, op1 ssa.Op, typ, rtyp types.Kind, emit atomicOpEmitter) intrinsicBuilder {
  4035  
  4036  		return func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4037  			// Target Atomic feature is identified by dynamic detection
  4038  			addr := s.entryNewValue1A(ssa.OpAddr, types.Types[types.TBOOL].PtrTo(), ir.Syms.ARM64HasATOMICS, s.sb)
  4039  			v := s.load(types.Types[types.TBOOL], addr)
  4040  			b := s.endBlock()
  4041  			b.Kind = ssa.BlockIf
  4042  			b.SetControl(v)
  4043  			bTrue := s.f.NewBlock(ssa.BlockPlain)
  4044  			bFalse := s.f.NewBlock(ssa.BlockPlain)
  4045  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  4046  			b.AddEdgeTo(bTrue)
  4047  			b.AddEdgeTo(bFalse)
  4048  			b.Likely = ssa.BranchLikely
  4049  
  4050  			// We have atomic instructions - use it directly.
  4051  			s.startBlock(bTrue)
  4052  			emit(s, n, args, op1, typ)
  4053  			s.endBlock().AddEdgeTo(bEnd)
  4054  
  4055  			// Use original instruction sequence.
  4056  			s.startBlock(bFalse)
  4057  			emit(s, n, args, op0, typ)
  4058  			s.endBlock().AddEdgeTo(bEnd)
  4059  
  4060  			// Merge results.
  4061  			s.startBlock(bEnd)
  4062  			if rtyp == types.TNIL {
  4063  				return nil
  4064  			} else {
  4065  				return s.variable(n, types.Types[rtyp])
  4066  			}
  4067  		}
  4068  	}
  4069  
  4070  	atomicXchgXaddEmitterARM64 := func(s *state, n *ir.CallExpr, args []*ssa.Value, op ssa.Op, typ types.Kind) {
  4071  		v := s.newValue3(op, types.NewTuple(types.Types[typ], types.TypeMem), args[0], args[1], s.mem())
  4072  		s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4073  		s.vars[n] = s.newValue1(ssa.OpSelect0, types.Types[typ], v)
  4074  	}
  4075  	addF("runtime/internal/atomic", "Xchg",
  4076  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicExchange32, ssa.OpAtomicExchange32Variant, types.TUINT32, types.TUINT32, atomicXchgXaddEmitterARM64),
  4077  		sys.ARM64)
  4078  	addF("runtime/internal/atomic", "Xchg64",
  4079  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicExchange64, ssa.OpAtomicExchange64Variant, types.TUINT64, types.TUINT64, atomicXchgXaddEmitterARM64),
  4080  		sys.ARM64)
  4081  
  4082  	addF("runtime/internal/atomic", "Xadd",
  4083  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4084  			v := s.newValue3(ssa.OpAtomicAdd32, types.NewTuple(types.Types[types.TUINT32], types.TypeMem), args[0], args[1], s.mem())
  4085  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4086  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT32], v)
  4087  		},
  4088  		sys.AMD64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4089  	addF("runtime/internal/atomic", "Xadd64",
  4090  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4091  			v := s.newValue3(ssa.OpAtomicAdd64, types.NewTuple(types.Types[types.TUINT64], types.TypeMem), args[0], args[1], s.mem())
  4092  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4093  			return s.newValue1(ssa.OpSelect0, types.Types[types.TUINT64], v)
  4094  		},
  4095  		sys.AMD64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4096  
  4097  	addF("runtime/internal/atomic", "Xadd",
  4098  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicAdd32, ssa.OpAtomicAdd32Variant, types.TUINT32, types.TUINT32, atomicXchgXaddEmitterARM64),
  4099  		sys.ARM64)
  4100  	addF("runtime/internal/atomic", "Xadd64",
  4101  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicAdd64, ssa.OpAtomicAdd64Variant, types.TUINT64, types.TUINT64, atomicXchgXaddEmitterARM64),
  4102  		sys.ARM64)
  4103  
  4104  	addF("runtime/internal/atomic", "Cas",
  4105  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4106  			v := s.newValue4(ssa.OpAtomicCompareAndSwap32, types.NewTuple(types.Types[types.TBOOL], types.TypeMem), args[0], args[1], args[2], s.mem())
  4107  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4108  			return s.newValue1(ssa.OpSelect0, types.Types[types.TBOOL], v)
  4109  		},
  4110  		sys.AMD64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4111  	addF("runtime/internal/atomic", "Cas64",
  4112  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4113  			v := s.newValue4(ssa.OpAtomicCompareAndSwap64, types.NewTuple(types.Types[types.TBOOL], types.TypeMem), args[0], args[1], args[2], s.mem())
  4114  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4115  			return s.newValue1(ssa.OpSelect0, types.Types[types.TBOOL], v)
  4116  		},
  4117  		sys.AMD64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X)
  4118  	addF("runtime/internal/atomic", "CasRel",
  4119  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4120  			v := s.newValue4(ssa.OpAtomicCompareAndSwap32, types.NewTuple(types.Types[types.TBOOL], types.TypeMem), args[0], args[1], args[2], s.mem())
  4121  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4122  			return s.newValue1(ssa.OpSelect0, types.Types[types.TBOOL], v)
  4123  		},
  4124  		sys.PPC64)
  4125  
  4126  	atomicCasEmitterARM64 := func(s *state, n *ir.CallExpr, args []*ssa.Value, op ssa.Op, typ types.Kind) {
  4127  		v := s.newValue4(op, types.NewTuple(types.Types[types.TBOOL], types.TypeMem), args[0], args[1], args[2], s.mem())
  4128  		s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, v)
  4129  		s.vars[n] = s.newValue1(ssa.OpSelect0, types.Types[typ], v)
  4130  	}
  4131  
  4132  	addF("runtime/internal/atomic", "Cas",
  4133  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicCompareAndSwap32, ssa.OpAtomicCompareAndSwap32Variant, types.TUINT32, types.TBOOL, atomicCasEmitterARM64),
  4134  		sys.ARM64)
  4135  	addF("runtime/internal/atomic", "Cas64",
  4136  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicCompareAndSwap64, ssa.OpAtomicCompareAndSwap64Variant, types.TUINT64, types.TBOOL, atomicCasEmitterARM64),
  4137  		sys.ARM64)
  4138  
  4139  	addF("runtime/internal/atomic", "And8",
  4140  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4141  			s.vars[memVar] = s.newValue3(ssa.OpAtomicAnd8, types.TypeMem, args[0], args[1], s.mem())
  4142  			return nil
  4143  		},
  4144  		sys.AMD64, sys.MIPS, sys.PPC64, sys.RISCV64, sys.S390X)
  4145  	addF("runtime/internal/atomic", "And",
  4146  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4147  			s.vars[memVar] = s.newValue3(ssa.OpAtomicAnd32, types.TypeMem, args[0], args[1], s.mem())
  4148  			return nil
  4149  		},
  4150  		sys.AMD64, sys.MIPS, sys.PPC64, sys.RISCV64, sys.S390X)
  4151  	addF("runtime/internal/atomic", "Or8",
  4152  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4153  			s.vars[memVar] = s.newValue3(ssa.OpAtomicOr8, types.TypeMem, args[0], args[1], s.mem())
  4154  			return nil
  4155  		},
  4156  		sys.AMD64, sys.ARM64, sys.MIPS, sys.PPC64, sys.RISCV64, sys.S390X)
  4157  	addF("runtime/internal/atomic", "Or",
  4158  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4159  			s.vars[memVar] = s.newValue3(ssa.OpAtomicOr32, types.TypeMem, args[0], args[1], s.mem())
  4160  			return nil
  4161  		},
  4162  		sys.AMD64, sys.MIPS, sys.PPC64, sys.RISCV64, sys.S390X)
  4163  
  4164  	atomicAndOrEmitterARM64 := func(s *state, n *ir.CallExpr, args []*ssa.Value, op ssa.Op, typ types.Kind) {
  4165  		s.vars[memVar] = s.newValue3(op, types.TypeMem, args[0], args[1], s.mem())
  4166  	}
  4167  
  4168  	addF("runtime/internal/atomic", "And8",
  4169  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicAnd8, ssa.OpAtomicAnd8Variant, types.TNIL, types.TNIL, atomicAndOrEmitterARM64),
  4170  		sys.ARM64)
  4171  	addF("runtime/internal/atomic", "And",
  4172  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicAnd32, ssa.OpAtomicAnd32Variant, types.TNIL, types.TNIL, atomicAndOrEmitterARM64),
  4173  		sys.ARM64)
  4174  	addF("runtime/internal/atomic", "Or8",
  4175  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicOr8, ssa.OpAtomicOr8Variant, types.TNIL, types.TNIL, atomicAndOrEmitterARM64),
  4176  		sys.ARM64)
  4177  	addF("runtime/internal/atomic", "Or",
  4178  		makeAtomicGuardedIntrinsicARM64(ssa.OpAtomicOr32, ssa.OpAtomicOr32Variant, types.TNIL, types.TNIL, atomicAndOrEmitterARM64),
  4179  		sys.ARM64)
  4180  
  4181  	// Aliases for atomic load operations
  4182  	alias("runtime/internal/atomic", "Loadint32", "runtime/internal/atomic", "Load", all...)
  4183  	alias("runtime/internal/atomic", "Loadint64", "runtime/internal/atomic", "Load64", all...)
  4184  	alias("runtime/internal/atomic", "Loaduintptr", "runtime/internal/atomic", "Load", p4...)
  4185  	alias("runtime/internal/atomic", "Loaduintptr", "runtime/internal/atomic", "Load64", p8...)
  4186  	alias("runtime/internal/atomic", "Loaduint", "runtime/internal/atomic", "Load", p4...)
  4187  	alias("runtime/internal/atomic", "Loaduint", "runtime/internal/atomic", "Load64", p8...)
  4188  	alias("runtime/internal/atomic", "LoadAcq", "runtime/internal/atomic", "Load", lwatomics...)
  4189  	alias("runtime/internal/atomic", "LoadAcq64", "runtime/internal/atomic", "Load64", lwatomics...)
  4190  	alias("runtime/internal/atomic", "LoadAcquintptr", "runtime/internal/atomic", "LoadAcq", p4...)
  4191  	alias("sync", "runtime_LoadAcquintptr", "runtime/internal/atomic", "LoadAcq", p4...) // linknamed
  4192  	alias("runtime/internal/atomic", "LoadAcquintptr", "runtime/internal/atomic", "LoadAcq64", p8...)
  4193  	alias("sync", "runtime_LoadAcquintptr", "runtime/internal/atomic", "LoadAcq64", p8...) // linknamed
  4194  
  4195  	// Aliases for atomic store operations
  4196  	alias("runtime/internal/atomic", "Storeint32", "runtime/internal/atomic", "Store", all...)
  4197  	alias("runtime/internal/atomic", "Storeint64", "runtime/internal/atomic", "Store64", all...)
  4198  	alias("runtime/internal/atomic", "Storeuintptr", "runtime/internal/atomic", "Store", p4...)
  4199  	alias("runtime/internal/atomic", "Storeuintptr", "runtime/internal/atomic", "Store64", p8...)
  4200  	alias("runtime/internal/atomic", "StoreRel", "runtime/internal/atomic", "Store", lwatomics...)
  4201  	alias("runtime/internal/atomic", "StoreRel64", "runtime/internal/atomic", "Store64", lwatomics...)
  4202  	alias("runtime/internal/atomic", "StoreReluintptr", "runtime/internal/atomic", "StoreRel", p4...)
  4203  	alias("sync", "runtime_StoreReluintptr", "runtime/internal/atomic", "StoreRel", p4...) // linknamed
  4204  	alias("runtime/internal/atomic", "StoreReluintptr", "runtime/internal/atomic", "StoreRel64", p8...)
  4205  	alias("sync", "runtime_StoreReluintptr", "runtime/internal/atomic", "StoreRel64", p8...) // linknamed
  4206  
  4207  	// Aliases for atomic swap operations
  4208  	alias("runtime/internal/atomic", "Xchgint32", "runtime/internal/atomic", "Xchg", all...)
  4209  	alias("runtime/internal/atomic", "Xchgint64", "runtime/internal/atomic", "Xchg64", all...)
  4210  	alias("runtime/internal/atomic", "Xchguintptr", "runtime/internal/atomic", "Xchg", p4...)
  4211  	alias("runtime/internal/atomic", "Xchguintptr", "runtime/internal/atomic", "Xchg64", p8...)
  4212  
  4213  	// Aliases for atomic add operations
  4214  	alias("runtime/internal/atomic", "Xaddint32", "runtime/internal/atomic", "Xadd", all...)
  4215  	alias("runtime/internal/atomic", "Xaddint64", "runtime/internal/atomic", "Xadd64", all...)
  4216  	alias("runtime/internal/atomic", "Xadduintptr", "runtime/internal/atomic", "Xadd", p4...)
  4217  	alias("runtime/internal/atomic", "Xadduintptr", "runtime/internal/atomic", "Xadd64", p8...)
  4218  
  4219  	// Aliases for atomic CAS operations
  4220  	alias("runtime/internal/atomic", "Casint32", "runtime/internal/atomic", "Cas", all...)
  4221  	alias("runtime/internal/atomic", "Casint64", "runtime/internal/atomic", "Cas64", all...)
  4222  	alias("runtime/internal/atomic", "Casuintptr", "runtime/internal/atomic", "Cas", p4...)
  4223  	alias("runtime/internal/atomic", "Casuintptr", "runtime/internal/atomic", "Cas64", p8...)
  4224  	alias("runtime/internal/atomic", "Casp1", "runtime/internal/atomic", "Cas", p4...)
  4225  	alias("runtime/internal/atomic", "Casp1", "runtime/internal/atomic", "Cas64", p8...)
  4226  	alias("runtime/internal/atomic", "CasRel", "runtime/internal/atomic", "Cas", lwatomics...)
  4227  
  4228  	/******** math ********/
  4229  	addF("math", "Sqrt",
  4230  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4231  			return s.newValue1(ssa.OpSqrt, types.Types[types.TFLOAT64], args[0])
  4232  		},
  4233  		sys.I386, sys.AMD64, sys.ARM, sys.ARM64, sys.MIPS, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X, sys.Wasm)
  4234  	addF("math", "Trunc",
  4235  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4236  			return s.newValue1(ssa.OpTrunc, types.Types[types.TFLOAT64], args[0])
  4237  		},
  4238  		sys.ARM64, sys.PPC64, sys.S390X, sys.Wasm)
  4239  	addF("math", "Ceil",
  4240  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4241  			return s.newValue1(ssa.OpCeil, types.Types[types.TFLOAT64], args[0])
  4242  		},
  4243  		sys.ARM64, sys.PPC64, sys.S390X, sys.Wasm)
  4244  	addF("math", "Floor",
  4245  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4246  			return s.newValue1(ssa.OpFloor, types.Types[types.TFLOAT64], args[0])
  4247  		},
  4248  		sys.ARM64, sys.PPC64, sys.S390X, sys.Wasm)
  4249  	addF("math", "Round",
  4250  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4251  			return s.newValue1(ssa.OpRound, types.Types[types.TFLOAT64], args[0])
  4252  		},
  4253  		sys.ARM64, sys.PPC64, sys.S390X)
  4254  	addF("math", "RoundToEven",
  4255  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4256  			return s.newValue1(ssa.OpRoundToEven, types.Types[types.TFLOAT64], args[0])
  4257  		},
  4258  		sys.ARM64, sys.S390X, sys.Wasm)
  4259  	addF("math", "Abs",
  4260  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4261  			return s.newValue1(ssa.OpAbs, types.Types[types.TFLOAT64], args[0])
  4262  		},
  4263  		sys.ARM64, sys.ARM, sys.PPC64, sys.RISCV64, sys.Wasm)
  4264  	addF("math", "Copysign",
  4265  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4266  			return s.newValue2(ssa.OpCopysign, types.Types[types.TFLOAT64], args[0], args[1])
  4267  		},
  4268  		sys.PPC64, sys.RISCV64, sys.Wasm)
  4269  	addF("math", "FMA",
  4270  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4271  			return s.newValue3(ssa.OpFMA, types.Types[types.TFLOAT64], args[0], args[1], args[2])
  4272  		},
  4273  		sys.ARM64, sys.PPC64, sys.RISCV64, sys.S390X)
  4274  	addF("math", "FMA",
  4275  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4276  			if !s.config.UseFMA {
  4277  				s.vars[n] = s.callResult(n, callNormal) // types.Types[TFLOAT64]
  4278  				return s.variable(n, types.Types[types.TFLOAT64])
  4279  			}
  4280  
  4281  			if buildcfg.GOAMD64 >= 3 {
  4282  				return s.newValue3(ssa.OpFMA, types.Types[types.TFLOAT64], args[0], args[1], args[2])
  4283  			}
  4284  
  4285  			v := s.entryNewValue0A(ssa.OpHasCPUFeature, types.Types[types.TBOOL], ir.Syms.X86HasFMA)
  4286  			b := s.endBlock()
  4287  			b.Kind = ssa.BlockIf
  4288  			b.SetControl(v)
  4289  			bTrue := s.f.NewBlock(ssa.BlockPlain)
  4290  			bFalse := s.f.NewBlock(ssa.BlockPlain)
  4291  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  4292  			b.AddEdgeTo(bTrue)
  4293  			b.AddEdgeTo(bFalse)
  4294  			b.Likely = ssa.BranchLikely // >= haswell cpus are common
  4295  
  4296  			// We have the intrinsic - use it directly.
  4297  			s.startBlock(bTrue)
  4298  			s.vars[n] = s.newValue3(ssa.OpFMA, types.Types[types.TFLOAT64], args[0], args[1], args[2])
  4299  			s.endBlock().AddEdgeTo(bEnd)
  4300  
  4301  			// Call the pure Go version.
  4302  			s.startBlock(bFalse)
  4303  			s.vars[n] = s.callResult(n, callNormal) // types.Types[TFLOAT64]
  4304  			s.endBlock().AddEdgeTo(bEnd)
  4305  
  4306  			// Merge results.
  4307  			s.startBlock(bEnd)
  4308  			return s.variable(n, types.Types[types.TFLOAT64])
  4309  		},
  4310  		sys.AMD64)
  4311  	addF("math", "FMA",
  4312  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4313  			if !s.config.UseFMA {
  4314  				s.vars[n] = s.callResult(n, callNormal) // types.Types[TFLOAT64]
  4315  				return s.variable(n, types.Types[types.TFLOAT64])
  4316  			}
  4317  			addr := s.entryNewValue1A(ssa.OpAddr, types.Types[types.TBOOL].PtrTo(), ir.Syms.ARMHasVFPv4, s.sb)
  4318  			v := s.load(types.Types[types.TBOOL], addr)
  4319  			b := s.endBlock()
  4320  			b.Kind = ssa.BlockIf
  4321  			b.SetControl(v)
  4322  			bTrue := s.f.NewBlock(ssa.BlockPlain)
  4323  			bFalse := s.f.NewBlock(ssa.BlockPlain)
  4324  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  4325  			b.AddEdgeTo(bTrue)
  4326  			b.AddEdgeTo(bFalse)
  4327  			b.Likely = ssa.BranchLikely
  4328  
  4329  			// We have the intrinsic - use it directly.
  4330  			s.startBlock(bTrue)
  4331  			s.vars[n] = s.newValue3(ssa.OpFMA, types.Types[types.TFLOAT64], args[0], args[1], args[2])
  4332  			s.endBlock().AddEdgeTo(bEnd)
  4333  
  4334  			// Call the pure Go version.
  4335  			s.startBlock(bFalse)
  4336  			s.vars[n] = s.callResult(n, callNormal) // types.Types[TFLOAT64]
  4337  			s.endBlock().AddEdgeTo(bEnd)
  4338  
  4339  			// Merge results.
  4340  			s.startBlock(bEnd)
  4341  			return s.variable(n, types.Types[types.TFLOAT64])
  4342  		},
  4343  		sys.ARM)
  4344  
  4345  	makeRoundAMD64 := func(op ssa.Op) func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4346  		return func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4347  			if buildcfg.GOAMD64 >= 2 {
  4348  				return s.newValue1(op, types.Types[types.TFLOAT64], args[0])
  4349  			}
  4350  
  4351  			v := s.entryNewValue0A(ssa.OpHasCPUFeature, types.Types[types.TBOOL], ir.Syms.X86HasSSE41)
  4352  			b := s.endBlock()
  4353  			b.Kind = ssa.BlockIf
  4354  			b.SetControl(v)
  4355  			bTrue := s.f.NewBlock(ssa.BlockPlain)
  4356  			bFalse := s.f.NewBlock(ssa.BlockPlain)
  4357  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  4358  			b.AddEdgeTo(bTrue)
  4359  			b.AddEdgeTo(bFalse)
  4360  			b.Likely = ssa.BranchLikely // most machines have sse4.1 nowadays
  4361  
  4362  			// We have the intrinsic - use it directly.
  4363  			s.startBlock(bTrue)
  4364  			s.vars[n] = s.newValue1(op, types.Types[types.TFLOAT64], args[0])
  4365  			s.endBlock().AddEdgeTo(bEnd)
  4366  
  4367  			// Call the pure Go version.
  4368  			s.startBlock(bFalse)
  4369  			s.vars[n] = s.callResult(n, callNormal) // types.Types[TFLOAT64]
  4370  			s.endBlock().AddEdgeTo(bEnd)
  4371  
  4372  			// Merge results.
  4373  			s.startBlock(bEnd)
  4374  			return s.variable(n, types.Types[types.TFLOAT64])
  4375  		}
  4376  	}
  4377  	addF("math", "RoundToEven",
  4378  		makeRoundAMD64(ssa.OpRoundToEven),
  4379  		sys.AMD64)
  4380  	addF("math", "Floor",
  4381  		makeRoundAMD64(ssa.OpFloor),
  4382  		sys.AMD64)
  4383  	addF("math", "Ceil",
  4384  		makeRoundAMD64(ssa.OpCeil),
  4385  		sys.AMD64)
  4386  	addF("math", "Trunc",
  4387  		makeRoundAMD64(ssa.OpTrunc),
  4388  		sys.AMD64)
  4389  
  4390  	/******** math/bits ********/
  4391  	addF("math/bits", "TrailingZeros64",
  4392  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4393  			return s.newValue1(ssa.OpCtz64, types.Types[types.TINT], args[0])
  4394  		},
  4395  		sys.AMD64, sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64, sys.Wasm)
  4396  	addF("math/bits", "TrailingZeros32",
  4397  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4398  			return s.newValue1(ssa.OpCtz32, types.Types[types.TINT], args[0])
  4399  		},
  4400  		sys.AMD64, sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64, sys.Wasm)
  4401  	addF("math/bits", "TrailingZeros16",
  4402  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4403  			x := s.newValue1(ssa.OpZeroExt16to32, types.Types[types.TUINT32], args[0])
  4404  			c := s.constInt32(types.Types[types.TUINT32], 1<<16)
  4405  			y := s.newValue2(ssa.OpOr32, types.Types[types.TUINT32], x, c)
  4406  			return s.newValue1(ssa.OpCtz32, types.Types[types.TINT], y)
  4407  		},
  4408  		sys.MIPS)
  4409  	addF("math/bits", "TrailingZeros16",
  4410  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4411  			return s.newValue1(ssa.OpCtz16, types.Types[types.TINT], args[0])
  4412  		},
  4413  		sys.AMD64, sys.I386, sys.ARM, sys.ARM64, sys.Wasm)
  4414  	addF("math/bits", "TrailingZeros16",
  4415  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4416  			x := s.newValue1(ssa.OpZeroExt16to64, types.Types[types.TUINT64], args[0])
  4417  			c := s.constInt64(types.Types[types.TUINT64], 1<<16)
  4418  			y := s.newValue2(ssa.OpOr64, types.Types[types.TUINT64], x, c)
  4419  			return s.newValue1(ssa.OpCtz64, types.Types[types.TINT], y)
  4420  		},
  4421  		sys.S390X, sys.PPC64)
  4422  	addF("math/bits", "TrailingZeros8",
  4423  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4424  			x := s.newValue1(ssa.OpZeroExt8to32, types.Types[types.TUINT32], args[0])
  4425  			c := s.constInt32(types.Types[types.TUINT32], 1<<8)
  4426  			y := s.newValue2(ssa.OpOr32, types.Types[types.TUINT32], x, c)
  4427  			return s.newValue1(ssa.OpCtz32, types.Types[types.TINT], y)
  4428  		},
  4429  		sys.MIPS)
  4430  	addF("math/bits", "TrailingZeros8",
  4431  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4432  			return s.newValue1(ssa.OpCtz8, types.Types[types.TINT], args[0])
  4433  		},
  4434  		sys.AMD64, sys.ARM, sys.ARM64, sys.Wasm)
  4435  	addF("math/bits", "TrailingZeros8",
  4436  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4437  			x := s.newValue1(ssa.OpZeroExt8to64, types.Types[types.TUINT64], args[0])
  4438  			c := s.constInt64(types.Types[types.TUINT64], 1<<8)
  4439  			y := s.newValue2(ssa.OpOr64, types.Types[types.TUINT64], x, c)
  4440  			return s.newValue1(ssa.OpCtz64, types.Types[types.TINT], y)
  4441  		},
  4442  		sys.S390X)
  4443  	alias("math/bits", "ReverseBytes64", "runtime/internal/sys", "Bswap64", all...)
  4444  	alias("math/bits", "ReverseBytes32", "runtime/internal/sys", "Bswap32", all...)
  4445  	// ReverseBytes inlines correctly, no need to intrinsify it.
  4446  	// ReverseBytes16 lowers to a rotate, no need for anything special here.
  4447  	addF("math/bits", "Len64",
  4448  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4449  			return s.newValue1(ssa.OpBitLen64, types.Types[types.TINT], args[0])
  4450  		},
  4451  		sys.AMD64, sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64, sys.Wasm)
  4452  	addF("math/bits", "Len32",
  4453  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4454  			return s.newValue1(ssa.OpBitLen32, types.Types[types.TINT], args[0])
  4455  		},
  4456  		sys.AMD64, sys.ARM64, sys.PPC64)
  4457  	addF("math/bits", "Len32",
  4458  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4459  			if s.config.PtrSize == 4 {
  4460  				return s.newValue1(ssa.OpBitLen32, types.Types[types.TINT], args[0])
  4461  			}
  4462  			x := s.newValue1(ssa.OpZeroExt32to64, types.Types[types.TUINT64], args[0])
  4463  			return s.newValue1(ssa.OpBitLen64, types.Types[types.TINT], x)
  4464  		},
  4465  		sys.ARM, sys.S390X, sys.MIPS, sys.Wasm)
  4466  	addF("math/bits", "Len16",
  4467  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4468  			if s.config.PtrSize == 4 {
  4469  				x := s.newValue1(ssa.OpZeroExt16to32, types.Types[types.TUINT32], args[0])
  4470  				return s.newValue1(ssa.OpBitLen32, types.Types[types.TINT], x)
  4471  			}
  4472  			x := s.newValue1(ssa.OpZeroExt16to64, types.Types[types.TUINT64], args[0])
  4473  			return s.newValue1(ssa.OpBitLen64, types.Types[types.TINT], x)
  4474  		},
  4475  		sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64, sys.Wasm)
  4476  	addF("math/bits", "Len16",
  4477  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4478  			return s.newValue1(ssa.OpBitLen16, types.Types[types.TINT], args[0])
  4479  		},
  4480  		sys.AMD64)
  4481  	addF("math/bits", "Len8",
  4482  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4483  			if s.config.PtrSize == 4 {
  4484  				x := s.newValue1(ssa.OpZeroExt8to32, types.Types[types.TUINT32], args[0])
  4485  				return s.newValue1(ssa.OpBitLen32, types.Types[types.TINT], x)
  4486  			}
  4487  			x := s.newValue1(ssa.OpZeroExt8to64, types.Types[types.TUINT64], args[0])
  4488  			return s.newValue1(ssa.OpBitLen64, types.Types[types.TINT], x)
  4489  		},
  4490  		sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64, sys.Wasm)
  4491  	addF("math/bits", "Len8",
  4492  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4493  			return s.newValue1(ssa.OpBitLen8, types.Types[types.TINT], args[0])
  4494  		},
  4495  		sys.AMD64)
  4496  	addF("math/bits", "Len",
  4497  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4498  			if s.config.PtrSize == 4 {
  4499  				return s.newValue1(ssa.OpBitLen32, types.Types[types.TINT], args[0])
  4500  			}
  4501  			return s.newValue1(ssa.OpBitLen64, types.Types[types.TINT], args[0])
  4502  		},
  4503  		sys.AMD64, sys.ARM64, sys.ARM, sys.S390X, sys.MIPS, sys.PPC64, sys.Wasm)
  4504  	// LeadingZeros is handled because it trivially calls Len.
  4505  	addF("math/bits", "Reverse64",
  4506  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4507  			return s.newValue1(ssa.OpBitRev64, types.Types[types.TINT], args[0])
  4508  		},
  4509  		sys.ARM64)
  4510  	addF("math/bits", "Reverse32",
  4511  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4512  			return s.newValue1(ssa.OpBitRev32, types.Types[types.TINT], args[0])
  4513  		},
  4514  		sys.ARM64)
  4515  	addF("math/bits", "Reverse16",
  4516  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4517  			return s.newValue1(ssa.OpBitRev16, types.Types[types.TINT], args[0])
  4518  		},
  4519  		sys.ARM64)
  4520  	addF("math/bits", "Reverse8",
  4521  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4522  			return s.newValue1(ssa.OpBitRev8, types.Types[types.TINT], args[0])
  4523  		},
  4524  		sys.ARM64)
  4525  	addF("math/bits", "Reverse",
  4526  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4527  			if s.config.PtrSize == 4 {
  4528  				return s.newValue1(ssa.OpBitRev32, types.Types[types.TINT], args[0])
  4529  			}
  4530  			return s.newValue1(ssa.OpBitRev64, types.Types[types.TINT], args[0])
  4531  		},
  4532  		sys.ARM64)
  4533  	addF("math/bits", "RotateLeft8",
  4534  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4535  			return s.newValue2(ssa.OpRotateLeft8, types.Types[types.TUINT8], args[0], args[1])
  4536  		},
  4537  		sys.AMD64)
  4538  	addF("math/bits", "RotateLeft16",
  4539  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4540  			return s.newValue2(ssa.OpRotateLeft16, types.Types[types.TUINT16], args[0], args[1])
  4541  		},
  4542  		sys.AMD64)
  4543  	addF("math/bits", "RotateLeft32",
  4544  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4545  			return s.newValue2(ssa.OpRotateLeft32, types.Types[types.TUINT32], args[0], args[1])
  4546  		},
  4547  		sys.AMD64, sys.ARM, sys.ARM64, sys.S390X, sys.PPC64, sys.Wasm)
  4548  	addF("math/bits", "RotateLeft64",
  4549  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4550  			return s.newValue2(ssa.OpRotateLeft64, types.Types[types.TUINT64], args[0], args[1])
  4551  		},
  4552  		sys.AMD64, sys.ARM64, sys.S390X, sys.PPC64, sys.Wasm)
  4553  	alias("math/bits", "RotateLeft", "math/bits", "RotateLeft64", p8...)
  4554  
  4555  	makeOnesCountAMD64 := func(op ssa.Op) func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4556  		return func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4557  			if buildcfg.GOAMD64 >= 2 {
  4558  				return s.newValue1(op, types.Types[types.TINT], args[0])
  4559  			}
  4560  
  4561  			v := s.entryNewValue0A(ssa.OpHasCPUFeature, types.Types[types.TBOOL], ir.Syms.X86HasPOPCNT)
  4562  			b := s.endBlock()
  4563  			b.Kind = ssa.BlockIf
  4564  			b.SetControl(v)
  4565  			bTrue := s.f.NewBlock(ssa.BlockPlain)
  4566  			bFalse := s.f.NewBlock(ssa.BlockPlain)
  4567  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  4568  			b.AddEdgeTo(bTrue)
  4569  			b.AddEdgeTo(bFalse)
  4570  			b.Likely = ssa.BranchLikely // most machines have popcnt nowadays
  4571  
  4572  			// We have the intrinsic - use it directly.
  4573  			s.startBlock(bTrue)
  4574  			s.vars[n] = s.newValue1(op, types.Types[types.TINT], args[0])
  4575  			s.endBlock().AddEdgeTo(bEnd)
  4576  
  4577  			// Call the pure Go version.
  4578  			s.startBlock(bFalse)
  4579  			s.vars[n] = s.callResult(n, callNormal) // types.Types[TINT]
  4580  			s.endBlock().AddEdgeTo(bEnd)
  4581  
  4582  			// Merge results.
  4583  			s.startBlock(bEnd)
  4584  			return s.variable(n, types.Types[types.TINT])
  4585  		}
  4586  	}
  4587  	addF("math/bits", "OnesCount64",
  4588  		makeOnesCountAMD64(ssa.OpPopCount64),
  4589  		sys.AMD64)
  4590  	addF("math/bits", "OnesCount64",
  4591  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4592  			return s.newValue1(ssa.OpPopCount64, types.Types[types.TINT], args[0])
  4593  		},
  4594  		sys.PPC64, sys.ARM64, sys.S390X, sys.Wasm)
  4595  	addF("math/bits", "OnesCount32",
  4596  		makeOnesCountAMD64(ssa.OpPopCount32),
  4597  		sys.AMD64)
  4598  	addF("math/bits", "OnesCount32",
  4599  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4600  			return s.newValue1(ssa.OpPopCount32, types.Types[types.TINT], args[0])
  4601  		},
  4602  		sys.PPC64, sys.ARM64, sys.S390X, sys.Wasm)
  4603  	addF("math/bits", "OnesCount16",
  4604  		makeOnesCountAMD64(ssa.OpPopCount16),
  4605  		sys.AMD64)
  4606  	addF("math/bits", "OnesCount16",
  4607  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4608  			return s.newValue1(ssa.OpPopCount16, types.Types[types.TINT], args[0])
  4609  		},
  4610  		sys.ARM64, sys.S390X, sys.PPC64, sys.Wasm)
  4611  	addF("math/bits", "OnesCount8",
  4612  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4613  			return s.newValue1(ssa.OpPopCount8, types.Types[types.TINT], args[0])
  4614  		},
  4615  		sys.S390X, sys.PPC64, sys.Wasm)
  4616  	addF("math/bits", "OnesCount",
  4617  		makeOnesCountAMD64(ssa.OpPopCount64),
  4618  		sys.AMD64)
  4619  	addF("math/bits", "Mul64",
  4620  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4621  			return s.newValue2(ssa.OpMul64uhilo, types.NewTuple(types.Types[types.TUINT64], types.Types[types.TUINT64]), args[0], args[1])
  4622  		},
  4623  		sys.AMD64, sys.ARM64, sys.PPC64, sys.S390X, sys.MIPS64, sys.RISCV64)
  4624  	alias("math/bits", "Mul", "math/bits", "Mul64", sys.ArchAMD64, sys.ArchARM64, sys.ArchPPC64, sys.ArchPPC64LE, sys.ArchS390X, sys.ArchMIPS64, sys.ArchMIPS64LE, sys.ArchRISCV64)
  4625  	alias("runtime/internal/math", "Mul64", "math/bits", "Mul64", sys.ArchAMD64, sys.ArchARM64, sys.ArchPPC64, sys.ArchPPC64LE, sys.ArchS390X, sys.ArchMIPS64, sys.ArchMIPS64LE, sys.ArchRISCV64)
  4626  	addF("math/bits", "Add64",
  4627  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4628  			return s.newValue3(ssa.OpAdd64carry, types.NewTuple(types.Types[types.TUINT64], types.Types[types.TUINT64]), args[0], args[1], args[2])
  4629  		},
  4630  		sys.AMD64, sys.ARM64, sys.PPC64, sys.S390X)
  4631  	alias("math/bits", "Add", "math/bits", "Add64", sys.ArchAMD64, sys.ArchARM64, sys.ArchPPC64, sys.ArchPPC64LE, sys.ArchS390X)
  4632  	addF("math/bits", "Sub64",
  4633  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4634  			return s.newValue3(ssa.OpSub64borrow, types.NewTuple(types.Types[types.TUINT64], types.Types[types.TUINT64]), args[0], args[1], args[2])
  4635  		},
  4636  		sys.AMD64, sys.ARM64, sys.S390X)
  4637  	alias("math/bits", "Sub", "math/bits", "Sub64", sys.ArchAMD64, sys.ArchARM64, sys.ArchS390X)
  4638  	addF("math/bits", "Div64",
  4639  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4640  			// check for divide-by-zero/overflow and panic with appropriate message
  4641  			cmpZero := s.newValue2(s.ssaOp(ir.ONE, types.Types[types.TUINT64]), types.Types[types.TBOOL], args[2], s.zeroVal(types.Types[types.TUINT64]))
  4642  			s.check(cmpZero, ir.Syms.Panicdivide)
  4643  			cmpOverflow := s.newValue2(s.ssaOp(ir.OLT, types.Types[types.TUINT64]), types.Types[types.TBOOL], args[0], args[2])
  4644  			s.check(cmpOverflow, ir.Syms.Panicoverflow)
  4645  			return s.newValue3(ssa.OpDiv128u, types.NewTuple(types.Types[types.TUINT64], types.Types[types.TUINT64]), args[0], args[1], args[2])
  4646  		},
  4647  		sys.AMD64)
  4648  	alias("math/bits", "Div", "math/bits", "Div64", sys.ArchAMD64)
  4649  
  4650  	alias("runtime/internal/sys", "Ctz8", "math/bits", "TrailingZeros8", all...)
  4651  	alias("runtime/internal/sys", "TrailingZeros8", "math/bits", "TrailingZeros8", all...)
  4652  	alias("runtime/internal/sys", "TrailingZeros64", "math/bits", "TrailingZeros64", all...)
  4653  	alias("runtime/internal/sys", "Len8", "math/bits", "Len8", all...)
  4654  	alias("runtime/internal/sys", "Len64", "math/bits", "Len64", all...)
  4655  	alias("runtime/internal/sys", "OnesCount64", "math/bits", "OnesCount64", all...)
  4656  
  4657  	/******** sync/atomic ********/
  4658  
  4659  	// Note: these are disabled by flag_race in findIntrinsic below.
  4660  	alias("sync/atomic", "LoadInt32", "runtime/internal/atomic", "Load", all...)
  4661  	alias("sync/atomic", "LoadInt64", "runtime/internal/atomic", "Load64", all...)
  4662  	alias("sync/atomic", "LoadPointer", "runtime/internal/atomic", "Loadp", all...)
  4663  	alias("sync/atomic", "LoadUint32", "runtime/internal/atomic", "Load", all...)
  4664  	alias("sync/atomic", "LoadUint64", "runtime/internal/atomic", "Load64", all...)
  4665  	alias("sync/atomic", "LoadUintptr", "runtime/internal/atomic", "Load", p4...)
  4666  	alias("sync/atomic", "LoadUintptr", "runtime/internal/atomic", "Load64", p8...)
  4667  
  4668  	alias("sync/atomic", "StoreInt32", "runtime/internal/atomic", "Store", all...)
  4669  	alias("sync/atomic", "StoreInt64", "runtime/internal/atomic", "Store64", all...)
  4670  	// Note: not StorePointer, that needs a write barrier.  Same below for {CompareAnd}Swap.
  4671  	alias("sync/atomic", "StoreUint32", "runtime/internal/atomic", "Store", all...)
  4672  	alias("sync/atomic", "StoreUint64", "runtime/internal/atomic", "Store64", all...)
  4673  	alias("sync/atomic", "StoreUintptr", "runtime/internal/atomic", "Store", p4...)
  4674  	alias("sync/atomic", "StoreUintptr", "runtime/internal/atomic", "Store64", p8...)
  4675  
  4676  	alias("sync/atomic", "SwapInt32", "runtime/internal/atomic", "Xchg", all...)
  4677  	alias("sync/atomic", "SwapInt64", "runtime/internal/atomic", "Xchg64", all...)
  4678  	alias("sync/atomic", "SwapUint32", "runtime/internal/atomic", "Xchg", all...)
  4679  	alias("sync/atomic", "SwapUint64", "runtime/internal/atomic", "Xchg64", all...)
  4680  	alias("sync/atomic", "SwapUintptr", "runtime/internal/atomic", "Xchg", p4...)
  4681  	alias("sync/atomic", "SwapUintptr", "runtime/internal/atomic", "Xchg64", p8...)
  4682  
  4683  	alias("sync/atomic", "CompareAndSwapInt32", "runtime/internal/atomic", "Cas", all...)
  4684  	alias("sync/atomic", "CompareAndSwapInt64", "runtime/internal/atomic", "Cas64", all...)
  4685  	alias("sync/atomic", "CompareAndSwapUint32", "runtime/internal/atomic", "Cas", all...)
  4686  	alias("sync/atomic", "CompareAndSwapUint64", "runtime/internal/atomic", "Cas64", all...)
  4687  	alias("sync/atomic", "CompareAndSwapUintptr", "runtime/internal/atomic", "Cas", p4...)
  4688  	alias("sync/atomic", "CompareAndSwapUintptr", "runtime/internal/atomic", "Cas64", p8...)
  4689  
  4690  	alias("sync/atomic", "AddInt32", "runtime/internal/atomic", "Xadd", all...)
  4691  	alias("sync/atomic", "AddInt64", "runtime/internal/atomic", "Xadd64", all...)
  4692  	alias("sync/atomic", "AddUint32", "runtime/internal/atomic", "Xadd", all...)
  4693  	alias("sync/atomic", "AddUint64", "runtime/internal/atomic", "Xadd64", all...)
  4694  	alias("sync/atomic", "AddUintptr", "runtime/internal/atomic", "Xadd", p4...)
  4695  	alias("sync/atomic", "AddUintptr", "runtime/internal/atomic", "Xadd64", p8...)
  4696  
  4697  	/******** math/big ********/
  4698  	add("math/big", "mulWW",
  4699  		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
  4700  			return s.newValue2(ssa.OpMul64uhilo, types.NewTuple(types.Types[types.TUINT64], types.Types[types.TUINT64]), args[0], args[1])
  4701  		},
  4702  		sys.ArchAMD64, sys.ArchARM64, sys.ArchPPC64LE, sys.ArchPPC64, sys.ArchS390X)
  4703  }
  4704  
  4705  // findIntrinsic returns a function which builds the SSA equivalent of the
  4706  // function identified by the symbol sym.  If sym is not an intrinsic call, returns nil.
  4707  func findIntrinsic(sym *types.Sym) intrinsicBuilder {
  4708  	if sym == nil || sym.Pkg == nil {
  4709  		return nil
  4710  	}
  4711  	pkg := sym.Pkg.Path
  4712  	if sym.Pkg == types.LocalPkg {
  4713  		pkg = base.Ctxt.Pkgpath
  4714  	}
  4715  	if sym.Pkg == ir.Pkgs.Runtime {
  4716  		pkg = "runtime"
  4717  	}
  4718  	if base.Flag.Race && pkg == "sync/atomic" {
  4719  		// The race detector needs to be able to intercept these calls.
  4720  		// We can't intrinsify them.
  4721  		return nil
  4722  	}
  4723  	// Skip intrinsifying math functions (which may contain hard-float
  4724  	// instructions) when soft-float
  4725  	if Arch.SoftFloat && pkg == "math" {
  4726  		return nil
  4727  	}
  4728  
  4729  	fn := sym.Name
  4730  	if ssa.IntrinsicsDisable {
  4731  		if pkg == "runtime" && (fn == "getcallerpc" || fn == "getcallersp" || fn == "getclosureptr") {
  4732  			// These runtime functions don't have definitions, must be intrinsics.
  4733  		} else {
  4734  			return nil
  4735  		}
  4736  	}
  4737  	return intrinsics[intrinsicKey{Arch.LinkArch.Arch, pkg, fn}]
  4738  }
  4739  
  4740  func IsIntrinsicCall(n *ir.CallExpr) bool {
  4741  	if n == nil {
  4742  		return false
  4743  	}
  4744  	name, ok := n.X.(*ir.Name)
  4745  	if !ok {
  4746  		return false
  4747  	}
  4748  	return findIntrinsic(name.Sym()) != nil
  4749  }
  4750  
  4751  // intrinsicCall converts a call to a recognized intrinsic function into the intrinsic SSA operation.
  4752  func (s *state) intrinsicCall(n *ir.CallExpr) *ssa.Value {
  4753  	v := findIntrinsic(n.X.Sym())(s, n, s.intrinsicArgs(n))
  4754  	if ssa.IntrinsicsDebug > 0 {
  4755  		x := v
  4756  		if x == nil {
  4757  			x = s.mem()
  4758  		}
  4759  		if x.Op == ssa.OpSelect0 || x.Op == ssa.OpSelect1 {
  4760  			x = x.Args[0]
  4761  		}
  4762  		base.WarnfAt(n.Pos(), "intrinsic substitution for %v with %s", n.X.Sym().Name, x.LongString())
  4763  	}
  4764  	return v
  4765  }
  4766  
  4767  // intrinsicArgs extracts args from n, evaluates them to SSA values, and returns them.
  4768  func (s *state) intrinsicArgs(n *ir.CallExpr) []*ssa.Value {
  4769  	args := make([]*ssa.Value, len(n.Args))
  4770  	for i, n := range n.Args {
  4771  		args[i] = s.expr(n)
  4772  	}
  4773  	return args
  4774  }
  4775  
  4776  // openDeferRecord adds code to evaluate and store the function for an open-code defer
  4777  // call, and records info about the defer, so we can generate proper code on the
  4778  // exit paths. n is the sub-node of the defer node that is the actual function
  4779  // call. We will also record funcdata information on where the function is stored
  4780  // (as well as the deferBits variable), and this will enable us to run the proper
  4781  // defer calls during panics.
  4782  func (s *state) openDeferRecord(n *ir.CallExpr) {
  4783  	if len(n.Args) != 0 || n.Op() != ir.OCALLFUNC || n.X.Type().NumResults() != 0 {
  4784  		s.Fatalf("defer call with arguments or results: %v", n)
  4785  	}
  4786  
  4787  	opendefer := &openDeferInfo{
  4788  		n: n,
  4789  	}
  4790  	fn := n.X
  4791  	// We must always store the function value in a stack slot for the
  4792  	// runtime panic code to use. But in the defer exit code, we will
  4793  	// call the function directly if it is a static function.
  4794  	closureVal := s.expr(fn)
  4795  	closure := s.openDeferSave(fn.Type(), closureVal)
  4796  	opendefer.closureNode = closure.Aux.(*ir.Name)
  4797  	if !(fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC) {
  4798  		opendefer.closure = closure
  4799  	}
  4800  	index := len(s.openDefers)
  4801  	s.openDefers = append(s.openDefers, opendefer)
  4802  
  4803  	// Update deferBits only after evaluation and storage to stack of
  4804  	// the function is successful.
  4805  	bitvalue := s.constInt8(types.Types[types.TUINT8], 1<<uint(index))
  4806  	newDeferBits := s.newValue2(ssa.OpOr8, types.Types[types.TUINT8], s.variable(deferBitsVar, types.Types[types.TUINT8]), bitvalue)
  4807  	s.vars[deferBitsVar] = newDeferBits
  4808  	s.store(types.Types[types.TUINT8], s.deferBitsAddr, newDeferBits)
  4809  }
  4810  
  4811  // openDeferSave generates SSA nodes to store a value (with type t) for an
  4812  // open-coded defer at an explicit autotmp location on the stack, so it can be
  4813  // reloaded and used for the appropriate call on exit. Type t must be a function type
  4814  // (therefore SSAable). val is the value to be stored. The function returns an SSA
  4815  // value representing a pointer to the autotmp location.
  4816  func (s *state) openDeferSave(t *types.Type, val *ssa.Value) *ssa.Value {
  4817  	if !TypeOK(t) {
  4818  		s.Fatalf("openDeferSave of non-SSA-able type %v val=%v", t, val)
  4819  	}
  4820  	if !t.HasPointers() {
  4821  		s.Fatalf("openDeferSave of pointerless type %v val=%v", t, val)
  4822  	}
  4823  	pos := val.Pos
  4824  	temp := typecheck.TempAt(pos.WithNotStmt(), s.curfn, t)
  4825  	temp.SetOpenDeferSlot(true)
  4826  	var addrTemp *ssa.Value
  4827  	// Use OpVarLive to make sure stack slot for the closure is not removed by
  4828  	// dead-store elimination
  4829  	if s.curBlock.ID != s.f.Entry.ID {
  4830  		// Force the tmp storing this defer function to be declared in the entry
  4831  		// block, so that it will be live for the defer exit code (which will
  4832  		// actually access it only if the associated defer call has been activated).
  4833  		s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarDef, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
  4834  		s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarLive, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
  4835  		addrTemp = s.f.Entry.NewValue2A(src.NoXPos, ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.defvars[s.f.Entry.ID][memVar])
  4836  	} else {
  4837  		// Special case if we're still in the entry block. We can't use
  4838  		// the above code, since s.defvars[s.f.Entry.ID] isn't defined
  4839  		// until we end the entry block with s.endBlock().
  4840  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, temp, s.mem(), false)
  4841  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, temp, s.mem(), false)
  4842  		addrTemp = s.newValue2Apos(ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.mem(), false)
  4843  	}
  4844  	// Since we may use this temp during exit depending on the
  4845  	// deferBits, we must define it unconditionally on entry.
  4846  	// Therefore, we must make sure it is zeroed out in the entry
  4847  	// block if it contains pointers, else GC may wrongly follow an
  4848  	// uninitialized pointer value.
  4849  	temp.SetNeedzero(true)
  4850  	// We are storing to the stack, hence we can avoid the full checks in
  4851  	// storeType() (no write barrier) and do a simple store().
  4852  	s.store(t, addrTemp, val)
  4853  	return addrTemp
  4854  }
  4855  
  4856  // openDeferExit generates SSA for processing all the open coded defers at exit.
  4857  // The code involves loading deferBits, and checking each of the bits to see if
  4858  // the corresponding defer statement was executed. For each bit that is turned
  4859  // on, the associated defer call is made.
  4860  func (s *state) openDeferExit() {
  4861  	deferExit := s.f.NewBlock(ssa.BlockPlain)
  4862  	s.endBlock().AddEdgeTo(deferExit)
  4863  	s.startBlock(deferExit)
  4864  	s.lastDeferExit = deferExit
  4865  	s.lastDeferCount = len(s.openDefers)
  4866  	zeroval := s.constInt8(types.Types[types.TUINT8], 0)
  4867  	// Test for and run defers in reverse order
  4868  	for i := len(s.openDefers) - 1; i >= 0; i-- {
  4869  		r := s.openDefers[i]
  4870  		bCond := s.f.NewBlock(ssa.BlockPlain)
  4871  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  4872  
  4873  		deferBits := s.variable(deferBitsVar, types.Types[types.TUINT8])
  4874  		// Generate code to check if the bit associated with the current
  4875  		// defer is set.
  4876  		bitval := s.constInt8(types.Types[types.TUINT8], 1<<uint(i))
  4877  		andval := s.newValue2(ssa.OpAnd8, types.Types[types.TUINT8], deferBits, bitval)
  4878  		eqVal := s.newValue2(ssa.OpEq8, types.Types[types.TBOOL], andval, zeroval)
  4879  		b := s.endBlock()
  4880  		b.Kind = ssa.BlockIf
  4881  		b.SetControl(eqVal)
  4882  		b.AddEdgeTo(bEnd)
  4883  		b.AddEdgeTo(bCond)
  4884  		bCond.AddEdgeTo(bEnd)
  4885  		s.startBlock(bCond)
  4886  
  4887  		// Clear this bit in deferBits and force store back to stack, so
  4888  		// we will not try to re-run this defer call if this defer call panics.
  4889  		nbitval := s.newValue1(ssa.OpCom8, types.Types[types.TUINT8], bitval)
  4890  		maskedval := s.newValue2(ssa.OpAnd8, types.Types[types.TUINT8], deferBits, nbitval)
  4891  		s.store(types.Types[types.TUINT8], s.deferBitsAddr, maskedval)
  4892  		// Use this value for following tests, so we keep previous
  4893  		// bits cleared.
  4894  		s.vars[deferBitsVar] = maskedval
  4895  
  4896  		// Generate code to call the function call of the defer, using the
  4897  		// closure that were stored in argtmps at the point of the defer
  4898  		// statement.
  4899  		fn := r.n.X
  4900  		stksize := fn.Type().ArgWidth()
  4901  		var callArgs []*ssa.Value
  4902  		var call *ssa.Value
  4903  		if r.closure != nil {
  4904  			v := s.load(r.closure.Type.Elem(), r.closure)
  4905  			s.maybeNilCheckClosure(v, callDefer)
  4906  			codeptr := s.rawLoad(types.Types[types.TUINTPTR], v)
  4907  			aux := ssa.ClosureAuxCall(s.f.ABIDefault.ABIAnalyzeTypes(nil, nil, nil))
  4908  			call = s.newValue2A(ssa.OpClosureLECall, aux.LateExpansionResultType(), aux, codeptr, v)
  4909  		} else {
  4910  			aux := ssa.StaticAuxCall(fn.(*ir.Name).Linksym(), s.f.ABIDefault.ABIAnalyzeTypes(nil, nil, nil))
  4911  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  4912  		}
  4913  		callArgs = append(callArgs, s.mem())
  4914  		call.AddArgs(callArgs...)
  4915  		call.AuxInt = stksize
  4916  		s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, 0, call)
  4917  		// Make sure that the stack slots with pointers are kept live
  4918  		// through the call (which is a pre-emption point). Also, we will
  4919  		// use the first call of the last defer exit to compute liveness
  4920  		// for the deferreturn, so we want all stack slots to be live.
  4921  		if r.closureNode != nil {
  4922  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, r.closureNode, s.mem(), false)
  4923  		}
  4924  
  4925  		s.endBlock()
  4926  		s.startBlock(bEnd)
  4927  	}
  4928  }
  4929  
  4930  func (s *state) callResult(n *ir.CallExpr, k callKind) *ssa.Value {
  4931  	return s.call(n, k, false)
  4932  }
  4933  
  4934  func (s *state) callAddr(n *ir.CallExpr, k callKind) *ssa.Value {
  4935  	return s.call(n, k, true)
  4936  }
  4937  
  4938  // Calls the function n using the specified call type.
  4939  // Returns the address of the return value (or nil if none).
  4940  func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool) *ssa.Value {
  4941  	s.prevCall = nil
  4942  	var callee *ir.Name    // target function (if static)
  4943  	var closure *ssa.Value // ptr to closure to run (if dynamic)
  4944  	var codeptr *ssa.Value // ptr to target code (if dynamic)
  4945  	var rcvr *ssa.Value    // receiver to set
  4946  	fn := n.X
  4947  	var ACArgs []*types.Type    // AuxCall args
  4948  	var ACResults []*types.Type // AuxCall results
  4949  	var callArgs []*ssa.Value   // For late-expansion, the args themselves (not stored, args to the call instead).
  4950  
  4951  	callABI := s.f.ABIDefault
  4952  
  4953  	if !buildcfg.Experiment.RegabiArgs {
  4954  		var magicFnNameSym *types.Sym
  4955  		if fn.Name() != nil {
  4956  			magicFnNameSym = fn.Name().Sym()
  4957  			ss := magicFnNameSym.Name
  4958  			if strings.HasSuffix(ss, magicNameDotSuffix) {
  4959  				callABI = s.f.ABI1
  4960  			}
  4961  		}
  4962  		if magicFnNameSym == nil && n.Op() == ir.OCALLINTER {
  4963  			magicFnNameSym = fn.(*ir.SelectorExpr).Sym()
  4964  			ss := magicFnNameSym.Name
  4965  			if strings.HasSuffix(ss, magicNameDotSuffix[1:]) {
  4966  				callABI = s.f.ABI1
  4967  			}
  4968  		}
  4969  	}
  4970  
  4971  	if k != callNormal && k != callTail && (len(n.Args) != 0 || n.Op() == ir.OCALLINTER || n.X.Type().NumResults() != 0) {
  4972  		s.Fatalf("go/defer call with arguments: %v", n)
  4973  	}
  4974  
  4975  	switch n.Op() {
  4976  	case ir.OCALLFUNC:
  4977  		if (k == callNormal || k == callTail) && fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC {
  4978  			fn := fn.(*ir.Name)
  4979  			callee = fn
  4980  			if buildcfg.Experiment.RegabiArgs {
  4981  				// This is a static call, so it may be
  4982  				// a direct call to a non-ABIInternal
  4983  				// function. fn.Func may be nil for
  4984  				// some compiler-generated functions,
  4985  				// but those are all ABIInternal.
  4986  				if fn.Func != nil {
  4987  					callABI = abiForFunc(fn.Func, s.f.ABI0, s.f.ABI1)
  4988  				}
  4989  			} else {
  4990  				// TODO(register args) remove after register abi is working
  4991  				inRegistersImported := fn.Pragma()&ir.RegisterParams != 0
  4992  				inRegistersSamePackage := fn.Func != nil && fn.Func.Pragma&ir.RegisterParams != 0
  4993  				if inRegistersImported || inRegistersSamePackage {
  4994  					callABI = s.f.ABI1
  4995  				}
  4996  			}
  4997  			break
  4998  		}
  4999  		closure = s.expr(fn)
  5000  		if k != callDefer && k != callDeferStack {
  5001  			// Deferred nil function needs to panic when the function is invoked,
  5002  			// not the point of defer statement.
  5003  			s.maybeNilCheckClosure(closure, k)
  5004  		}
  5005  	case ir.OCALLINTER:
  5006  		if fn.Op() != ir.ODOTINTER {
  5007  			s.Fatalf("OCALLINTER: n.Left not an ODOTINTER: %v", fn.Op())
  5008  		}
  5009  		fn := fn.(*ir.SelectorExpr)
  5010  		var iclosure *ssa.Value
  5011  		iclosure, rcvr = s.getClosureAndRcvr(fn)
  5012  		if k == callNormal {
  5013  			codeptr = s.load(types.Types[types.TUINTPTR], iclosure)
  5014  		} else {
  5015  			closure = iclosure
  5016  		}
  5017  	}
  5018  
  5019  	if !buildcfg.Experiment.RegabiArgs {
  5020  		if regAbiForFuncType(n.X.Type().FuncType()) {
  5021  			// Magic last type in input args to call
  5022  			callABI = s.f.ABI1
  5023  		}
  5024  	}
  5025  
  5026  	params := callABI.ABIAnalyze(n.X.Type(), false /* Do not set (register) nNames from caller side -- can cause races. */)
  5027  	types.CalcSize(fn.Type())
  5028  	stksize := params.ArgWidth() // includes receiver, args, and results
  5029  
  5030  	res := n.X.Type().Results()
  5031  	if k == callNormal || k == callTail {
  5032  		for _, p := range params.OutParams() {
  5033  			ACResults = append(ACResults, p.Type)
  5034  		}
  5035  	}
  5036  
  5037  	var call *ssa.Value
  5038  	if k == callDeferStack {
  5039  		// Make a defer struct d on the stack.
  5040  		if stksize != 0 {
  5041  			s.Fatalf("deferprocStack with non-zero stack size %d: %v", stksize, n)
  5042  		}
  5043  
  5044  		t := deferstruct()
  5045  		d := typecheck.TempAt(n.Pos(), s.curfn, t)
  5046  
  5047  		s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, d, s.mem())
  5048  		addr := s.addr(d)
  5049  
  5050  		// Must match deferstruct() below and src/runtime/runtime2.go:_defer.
  5051  		// 0: started, set in deferprocStack
  5052  		// 1: heap, set in deferprocStack
  5053  		// 2: openDefer
  5054  		// 3: sp, set in deferprocStack
  5055  		// 4: pc, set in deferprocStack
  5056  		// 5: fn
  5057  		s.store(closure.Type,
  5058  			s.newValue1I(ssa.OpOffPtr, closure.Type.PtrTo(), t.FieldOff(5), addr),
  5059  			closure)
  5060  		// 6: panic, set in deferprocStack
  5061  		// 7: link, set in deferprocStack
  5062  		// 8: fd
  5063  		// 9: varp
  5064  		// 10: framepc
  5065  
  5066  		// Call runtime.deferprocStack with pointer to _defer record.
  5067  		ACArgs = append(ACArgs, types.Types[types.TUINTPTR])
  5068  		aux := ssa.StaticAuxCall(ir.Syms.DeferprocStack, s.f.ABIDefault.ABIAnalyzeTypes(nil, ACArgs, ACResults))
  5069  		callArgs = append(callArgs, addr, s.mem())
  5070  		call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5071  		call.AddArgs(callArgs...)
  5072  		call.AuxInt = int64(types.PtrSize) // deferprocStack takes a *_defer arg
  5073  	} else {
  5074  		// Store arguments to stack, including defer/go arguments and receiver for method calls.
  5075  		// These are written in SP-offset order.
  5076  		argStart := base.Ctxt.FixedFrameSize()
  5077  		// Defer/go args.
  5078  		if k != callNormal && k != callTail {
  5079  			// Write closure (arg to newproc/deferproc).
  5080  			ACArgs = append(ACArgs, types.Types[types.TUINTPTR]) // not argExtra
  5081  			callArgs = append(callArgs, closure)
  5082  			stksize += int64(types.PtrSize)
  5083  			argStart += int64(types.PtrSize)
  5084  		}
  5085  
  5086  		// Set receiver (for interface calls).
  5087  		if rcvr != nil {
  5088  			callArgs = append(callArgs, rcvr)
  5089  		}
  5090  
  5091  		// Write args.
  5092  		t := n.X.Type()
  5093  		args := n.Args
  5094  
  5095  		for _, p := range params.InParams() { // includes receiver for interface calls
  5096  			ACArgs = append(ACArgs, p.Type)
  5097  		}
  5098  
  5099  		// Split the entry block if there are open defers, because later calls to
  5100  		// openDeferSave may cause a mismatch between the mem for an OpDereference
  5101  		// and the call site which uses it. See #49282.
  5102  		if s.curBlock.ID == s.f.Entry.ID && s.hasOpenDefers {
  5103  			b := s.endBlock()
  5104  			b.Kind = ssa.BlockPlain
  5105  			curb := s.f.NewBlock(ssa.BlockPlain)
  5106  			b.AddEdgeTo(curb)
  5107  			s.startBlock(curb)
  5108  		}
  5109  
  5110  		for i, n := range args {
  5111  			callArgs = append(callArgs, s.putArg(n, t.Params().Field(i).Type))
  5112  		}
  5113  
  5114  		callArgs = append(callArgs, s.mem())
  5115  
  5116  		// call target
  5117  		switch {
  5118  		case k == callDefer:
  5119  			aux := ssa.StaticAuxCall(ir.Syms.Deferproc, s.f.ABIDefault.ABIAnalyzeTypes(nil, ACArgs, ACResults)) // TODO paramResultInfo for DeferProc
  5120  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5121  		case k == callGo:
  5122  			aux := ssa.StaticAuxCall(ir.Syms.Newproc, s.f.ABIDefault.ABIAnalyzeTypes(nil, ACArgs, ACResults))
  5123  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux) // TODO paramResultInfo for NewProc
  5124  		case closure != nil:
  5125  			// rawLoad because loading the code pointer from a
  5126  			// closure is always safe, but IsSanitizerSafeAddr
  5127  			// can't always figure that out currently, and it's
  5128  			// critical that we not clobber any arguments already
  5129  			// stored onto the stack.
  5130  			codeptr = s.rawLoad(types.Types[types.TUINTPTR], closure)
  5131  			aux := ssa.ClosureAuxCall(callABI.ABIAnalyzeTypes(nil, ACArgs, ACResults))
  5132  			call = s.newValue2A(ssa.OpClosureLECall, aux.LateExpansionResultType(), aux, codeptr, closure)
  5133  		case codeptr != nil:
  5134  			// Note that the "receiver" parameter is nil because the actual receiver is the first input parameter.
  5135  			aux := ssa.InterfaceAuxCall(params)
  5136  			call = s.newValue1A(ssa.OpInterLECall, aux.LateExpansionResultType(), aux, codeptr)
  5137  		case callee != nil:
  5138  			aux := ssa.StaticAuxCall(callTargetLSym(callee), params)
  5139  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5140  			if k == callTail {
  5141  				call.Op = ssa.OpTailLECall
  5142  				stksize = 0 // Tail call does not use stack. We reuse caller's frame.
  5143  			}
  5144  		default:
  5145  			s.Fatalf("bad call type %v %v", n.Op(), n)
  5146  		}
  5147  		call.AddArgs(callArgs...)
  5148  		call.AuxInt = stksize // Call operations carry the argsize of the callee along with them
  5149  	}
  5150  	s.prevCall = call
  5151  	s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, int64(len(ACResults)), call)
  5152  	// Insert OVARLIVE nodes
  5153  	for _, name := range n.KeepAlive {
  5154  		s.stmt(ir.NewUnaryExpr(n.Pos(), ir.OVARLIVE, name))
  5155  	}
  5156  
  5157  	// Finish block for defers
  5158  	if k == callDefer || k == callDeferStack {
  5159  		b := s.endBlock()
  5160  		b.Kind = ssa.BlockDefer
  5161  		b.SetControl(call)
  5162  		bNext := s.f.NewBlock(ssa.BlockPlain)
  5163  		b.AddEdgeTo(bNext)
  5164  		// Add recover edge to exit code.
  5165  		r := s.f.NewBlock(ssa.BlockPlain)
  5166  		s.startBlock(r)
  5167  		s.exit()
  5168  		b.AddEdgeTo(r)
  5169  		b.Likely = ssa.BranchLikely
  5170  		s.startBlock(bNext)
  5171  	}
  5172  
  5173  	if res.NumFields() == 0 || k != callNormal {
  5174  		// call has no return value. Continue with the next statement.
  5175  		return nil
  5176  	}
  5177  	fp := res.Field(0)
  5178  	if returnResultAddr {
  5179  		return s.resultAddrOfCall(call, 0, fp.Type)
  5180  	}
  5181  	return s.newValue1I(ssa.OpSelectN, fp.Type, 0, call)
  5182  }
  5183  
  5184  // maybeNilCheckClosure checks if a nil check of a closure is needed in some
  5185  // architecture-dependent situations and, if so, emits the nil check.
  5186  func (s *state) maybeNilCheckClosure(closure *ssa.Value, k callKind) {
  5187  	if Arch.LinkArch.Family == sys.Wasm || buildcfg.GOOS == "aix" && k != callGo {
  5188  		// On AIX, the closure needs to be verified as fn can be nil, except if it's a call go. This needs to be handled by the runtime to have the "go of nil func value" error.
  5189  		// TODO(neelance): On other architectures this should be eliminated by the optimization steps
  5190  		s.nilCheck(closure)
  5191  	}
  5192  }
  5193  
  5194  // getClosureAndRcvr returns values for the appropriate closure and receiver of an
  5195  // interface call
  5196  func (s *state) getClosureAndRcvr(fn *ir.SelectorExpr) (*ssa.Value, *ssa.Value) {
  5197  	i := s.expr(fn.X)
  5198  	itab := s.newValue1(ssa.OpITab, types.Types[types.TUINTPTR], i)
  5199  	s.nilCheck(itab)
  5200  	itabidx := fn.Offset() + 2*int64(types.PtrSize) + 8 // offset of fun field in runtime.itab
  5201  	closure := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.UintptrPtr, itabidx, itab)
  5202  	rcvr := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, i)
  5203  	return closure, rcvr
  5204  }
  5205  
  5206  // etypesign returns the signed-ness of e, for integer/pointer etypes.
  5207  // -1 means signed, +1 means unsigned, 0 means non-integer/non-pointer.
  5208  func etypesign(e types.Kind) int8 {
  5209  	switch e {
  5210  	case types.TINT8, types.TINT16, types.TINT32, types.TINT64, types.TINT:
  5211  		return -1
  5212  	case types.TUINT8, types.TUINT16, types.TUINT32, types.TUINT64, types.TUINT, types.TUINTPTR, types.TUNSAFEPTR:
  5213  		return +1
  5214  	}
  5215  	return 0
  5216  }
  5217  
  5218  // addr converts the address of the expression n to SSA, adds it to s and returns the SSA result.
  5219  // The value that the returned Value represents is guaranteed to be non-nil.
  5220  func (s *state) addr(n ir.Node) *ssa.Value {
  5221  	if n.Op() != ir.ONAME {
  5222  		s.pushLine(n.Pos())
  5223  		defer s.popLine()
  5224  	}
  5225  
  5226  	if s.canSSA(n) {
  5227  		s.Fatalf("addr of canSSA expression: %+v", n)
  5228  	}
  5229  
  5230  	t := types.NewPtr(n.Type())
  5231  	linksymOffset := func(lsym *obj.LSym, offset int64) *ssa.Value {
  5232  		v := s.entryNewValue1A(ssa.OpAddr, t, lsym, s.sb)
  5233  		// TODO: Make OpAddr use AuxInt as well as Aux.
  5234  		if offset != 0 {
  5235  			v = s.entryNewValue1I(ssa.OpOffPtr, v.Type, offset, v)
  5236  		}
  5237  		return v
  5238  	}
  5239  	switch n.Op() {
  5240  	case ir.OLINKSYMOFFSET:
  5241  		no := n.(*ir.LinksymOffsetExpr)
  5242  		return linksymOffset(no.Linksym, no.Offset_)
  5243  	case ir.ONAME:
  5244  		n := n.(*ir.Name)
  5245  		if n.Heapaddr != nil {
  5246  			return s.expr(n.Heapaddr)
  5247  		}
  5248  		switch n.Class {
  5249  		case ir.PEXTERN:
  5250  			// global variable
  5251  			return linksymOffset(n.Linksym(), 0)
  5252  		case ir.PPARAM:
  5253  			// parameter slot
  5254  			v := s.decladdrs[n]
  5255  			if v != nil {
  5256  				return v
  5257  			}
  5258  			s.Fatalf("addr of undeclared ONAME %v. declared: %v", n, s.decladdrs)
  5259  			return nil
  5260  		case ir.PAUTO:
  5261  			return s.newValue2Apos(ssa.OpLocalAddr, t, n, s.sp, s.mem(), !ir.IsAutoTmp(n))
  5262  
  5263  		case ir.PPARAMOUT: // Same as PAUTO -- cannot generate LEA early.
  5264  			// ensure that we reuse symbols for out parameters so
  5265  			// that cse works on their addresses
  5266  			return s.newValue2Apos(ssa.OpLocalAddr, t, n, s.sp, s.mem(), true)
  5267  		default:
  5268  			s.Fatalf("variable address class %v not implemented", n.Class)
  5269  			return nil
  5270  		}
  5271  	case ir.ORESULT:
  5272  		// load return from callee
  5273  		n := n.(*ir.ResultExpr)
  5274  		return s.resultAddrOfCall(s.prevCall, n.Index, n.Type())
  5275  	case ir.OINDEX:
  5276  		n := n.(*ir.IndexExpr)
  5277  		if n.X.Type().IsSlice() {
  5278  			a := s.expr(n.X)
  5279  			i := s.expr(n.Index)
  5280  			len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], a)
  5281  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  5282  			p := s.newValue1(ssa.OpSlicePtr, t, a)
  5283  			return s.newValue2(ssa.OpPtrIndex, t, p, i)
  5284  		} else { // array
  5285  			a := s.addr(n.X)
  5286  			i := s.expr(n.Index)
  5287  			len := s.constInt(types.Types[types.TINT], n.X.Type().NumElem())
  5288  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  5289  			return s.newValue2(ssa.OpPtrIndex, types.NewPtr(n.X.Type().Elem()), a, i)
  5290  		}
  5291  	case ir.ODEREF:
  5292  		n := n.(*ir.StarExpr)
  5293  		return s.exprPtr(n.X, n.Bounded(), n.Pos())
  5294  	case ir.ODOT:
  5295  		n := n.(*ir.SelectorExpr)
  5296  		p := s.addr(n.X)
  5297  		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
  5298  	case ir.ODOTPTR:
  5299  		n := n.(*ir.SelectorExpr)
  5300  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  5301  		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
  5302  	case ir.OCONVNOP:
  5303  		n := n.(*ir.ConvExpr)
  5304  		if n.Type() == n.X.Type() {
  5305  			return s.addr(n.X)
  5306  		}
  5307  		addr := s.addr(n.X)
  5308  		return s.newValue1(ssa.OpCopy, t, addr) // ensure that addr has the right type
  5309  	case ir.OCALLFUNC, ir.OCALLINTER:
  5310  		n := n.(*ir.CallExpr)
  5311  		return s.callAddr(n, callNormal)
  5312  	case ir.ODOTTYPE, ir.ODYNAMICDOTTYPE:
  5313  		var v *ssa.Value
  5314  		if n.Op() == ir.ODOTTYPE {
  5315  			v, _ = s.dottype(n.(*ir.TypeAssertExpr), false)
  5316  		} else {
  5317  			v, _ = s.dynamicDottype(n.(*ir.DynamicTypeAssertExpr), false)
  5318  		}
  5319  		if v.Op != ssa.OpLoad {
  5320  			s.Fatalf("dottype of non-load")
  5321  		}
  5322  		if v.Args[1] != s.mem() {
  5323  			s.Fatalf("memory no longer live from dottype load")
  5324  		}
  5325  		return v.Args[0]
  5326  	default:
  5327  		s.Fatalf("unhandled addr %v", n.Op())
  5328  		return nil
  5329  	}
  5330  }
  5331  
  5332  // canSSA reports whether n is SSA-able.
  5333  // n must be an ONAME (or an ODOT sequence with an ONAME base).
  5334  func (s *state) canSSA(n ir.Node) bool {
  5335  	if base.Flag.N != 0 {
  5336  		return false
  5337  	}
  5338  	for {
  5339  		nn := n
  5340  		if nn.Op() == ir.ODOT {
  5341  			nn := nn.(*ir.SelectorExpr)
  5342  			n = nn.X
  5343  			continue
  5344  		}
  5345  		if nn.Op() == ir.OINDEX {
  5346  			nn := nn.(*ir.IndexExpr)
  5347  			if nn.X.Type().IsArray() {
  5348  				n = nn.X
  5349  				continue
  5350  			}
  5351  		}
  5352  		break
  5353  	}
  5354  	if n.Op() != ir.ONAME {
  5355  		return false
  5356  	}
  5357  	return s.canSSAName(n.(*ir.Name)) && TypeOK(n.Type())
  5358  }
  5359  
  5360  func (s *state) canSSAName(name *ir.Name) bool {
  5361  	if name.Addrtaken() || !name.OnStack() {
  5362  		return false
  5363  	}
  5364  	switch name.Class {
  5365  	case ir.PPARAMOUT:
  5366  		if s.hasdefer {
  5367  			// TODO: handle this case? Named return values must be
  5368  			// in memory so that the deferred function can see them.
  5369  			// Maybe do: if !strings.HasPrefix(n.String(), "~") { return false }
  5370  			// Or maybe not, see issue 18860.  Even unnamed return values
  5371  			// must be written back so if a defer recovers, the caller can see them.
  5372  			return false
  5373  		}
  5374  		if s.cgoUnsafeArgs {
  5375  			// Cgo effectively takes the address of all result args,
  5376  			// but the compiler can't see that.
  5377  			return false
  5378  		}
  5379  	}
  5380  	return true
  5381  	// TODO: try to make more variables SSAable?
  5382  }
  5383  
  5384  // TypeOK reports whether variables of type t are SSA-able.
  5385  func TypeOK(t *types.Type) bool {
  5386  	types.CalcSize(t)
  5387  	if t.Size() > int64(4*types.PtrSize) {
  5388  		// 4*Widthptr is an arbitrary constant. We want it
  5389  		// to be at least 3*Widthptr so slices can be registerized.
  5390  		// Too big and we'll introduce too much register pressure.
  5391  		return false
  5392  	}
  5393  	switch t.Kind() {
  5394  	case types.TARRAY:
  5395  		// We can't do larger arrays because dynamic indexing is
  5396  		// not supported on SSA variables.
  5397  		// TODO: allow if all indexes are constant.
  5398  		if t.NumElem() <= 1 {
  5399  			return TypeOK(t.Elem())
  5400  		}
  5401  		return false
  5402  	case types.TSTRUCT:
  5403  		if t.NumFields() > ssa.MaxStruct {
  5404  			return false
  5405  		}
  5406  		for _, t1 := range t.Fields().Slice() {
  5407  			if !TypeOK(t1.Type) {
  5408  				return false
  5409  			}
  5410  		}
  5411  		return true
  5412  	default:
  5413  		return true
  5414  	}
  5415  }
  5416  
  5417  // exprPtr evaluates n to a pointer and nil-checks it.
  5418  func (s *state) exprPtr(n ir.Node, bounded bool, lineno src.XPos) *ssa.Value {
  5419  	p := s.expr(n)
  5420  	if bounded || n.NonNil() {
  5421  		if s.f.Frontend().Debug_checknil() && lineno.Line() > 1 {
  5422  			s.f.Warnl(lineno, "removed nil check")
  5423  		}
  5424  		return p
  5425  	}
  5426  	s.nilCheck(p)
  5427  	return p
  5428  }
  5429  
  5430  // nilCheck generates nil pointer checking code.
  5431  // Used only for automatically inserted nil checks,
  5432  // not for user code like 'x != nil'.
  5433  func (s *state) nilCheck(ptr *ssa.Value) {
  5434  	if base.Debug.DisableNil != 0 || s.curfn.NilCheckDisabled() {
  5435  		return
  5436  	}
  5437  	s.newValue2(ssa.OpNilCheck, types.TypeVoid, ptr, s.mem())
  5438  }
  5439  
  5440  // boundsCheck generates bounds checking code. Checks if 0 <= idx <[=] len, branches to exit if not.
  5441  // Starts a new block on return.
  5442  // On input, len must be converted to full int width and be nonnegative.
  5443  // Returns idx converted to full int width.
  5444  // If bounded is true then caller guarantees the index is not out of bounds
  5445  // (but boundsCheck will still extend the index to full int width).
  5446  func (s *state) boundsCheck(idx, len *ssa.Value, kind ssa.BoundsKind, bounded bool) *ssa.Value {
  5447  	idx = s.extendIndex(idx, len, kind, bounded)
  5448  
  5449  	if bounded || base.Flag.B != 0 {
  5450  		// If bounded or bounds checking is flag-disabled, then no check necessary,
  5451  		// just return the extended index.
  5452  		//
  5453  		// Here, bounded == true if the compiler generated the index itself,
  5454  		// such as in the expansion of a slice initializer. These indexes are
  5455  		// compiler-generated, not Go program variables, so they cannot be
  5456  		// attacker-controlled, so we can omit Spectre masking as well.
  5457  		//
  5458  		// Note that we do not want to omit Spectre masking in code like:
  5459  		//
  5460  		//	if 0 <= i && i < len(x) {
  5461  		//		use(x[i])
  5462  		//	}
  5463  		//
  5464  		// Lucky for us, bounded==false for that code.
  5465  		// In that case (handled below), we emit a bound check (and Spectre mask)
  5466  		// and then the prove pass will remove the bounds check.
  5467  		// In theory the prove pass could potentially remove certain
  5468  		// Spectre masks, but it's very delicate and probably better
  5469  		// to be conservative and leave them all in.
  5470  		return idx
  5471  	}
  5472  
  5473  	bNext := s.f.NewBlock(ssa.BlockPlain)
  5474  	bPanic := s.f.NewBlock(ssa.BlockExit)
  5475  
  5476  	if !idx.Type.IsSigned() {
  5477  		switch kind {
  5478  		case ssa.BoundsIndex:
  5479  			kind = ssa.BoundsIndexU
  5480  		case ssa.BoundsSliceAlen:
  5481  			kind = ssa.BoundsSliceAlenU
  5482  		case ssa.BoundsSliceAcap:
  5483  			kind = ssa.BoundsSliceAcapU
  5484  		case ssa.BoundsSliceB:
  5485  			kind = ssa.BoundsSliceBU
  5486  		case ssa.BoundsSlice3Alen:
  5487  			kind = ssa.BoundsSlice3AlenU
  5488  		case ssa.BoundsSlice3Acap:
  5489  			kind = ssa.BoundsSlice3AcapU
  5490  		case ssa.BoundsSlice3B:
  5491  			kind = ssa.BoundsSlice3BU
  5492  		case ssa.BoundsSlice3C:
  5493  			kind = ssa.BoundsSlice3CU
  5494  		}
  5495  	}
  5496  
  5497  	var cmp *ssa.Value
  5498  	if kind == ssa.BoundsIndex || kind == ssa.BoundsIndexU {
  5499  		cmp = s.newValue2(ssa.OpIsInBounds, types.Types[types.TBOOL], idx, len)
  5500  	} else {
  5501  		cmp = s.newValue2(ssa.OpIsSliceInBounds, types.Types[types.TBOOL], idx, len)
  5502  	}
  5503  	b := s.endBlock()
  5504  	b.Kind = ssa.BlockIf
  5505  	b.SetControl(cmp)
  5506  	b.Likely = ssa.BranchLikely
  5507  	b.AddEdgeTo(bNext)
  5508  	b.AddEdgeTo(bPanic)
  5509  
  5510  	s.startBlock(bPanic)
  5511  	if Arch.LinkArch.Family == sys.Wasm {
  5512  		// TODO(khr): figure out how to do "register" based calling convention for bounds checks.
  5513  		// Should be similar to gcWriteBarrier, but I can't make it work.
  5514  		s.rtcall(BoundsCheckFunc[kind], false, nil, idx, len)
  5515  	} else {
  5516  		mem := s.newValue3I(ssa.OpPanicBounds, types.TypeMem, int64(kind), idx, len, s.mem())
  5517  		s.endBlock().SetControl(mem)
  5518  	}
  5519  	s.startBlock(bNext)
  5520  
  5521  	// In Spectre index mode, apply an appropriate mask to avoid speculative out-of-bounds accesses.
  5522  	if base.Flag.Cfg.SpectreIndex {
  5523  		op := ssa.OpSpectreIndex
  5524  		if kind != ssa.BoundsIndex && kind != ssa.BoundsIndexU {
  5525  			op = ssa.OpSpectreSliceIndex
  5526  		}
  5527  		idx = s.newValue2(op, types.Types[types.TINT], idx, len)
  5528  	}
  5529  
  5530  	return idx
  5531  }
  5532  
  5533  // If cmp (a bool) is false, panic using the given function.
  5534  func (s *state) check(cmp *ssa.Value, fn *obj.LSym) {
  5535  	b := s.endBlock()
  5536  	b.Kind = ssa.BlockIf
  5537  	b.SetControl(cmp)
  5538  	b.Likely = ssa.BranchLikely
  5539  	bNext := s.f.NewBlock(ssa.BlockPlain)
  5540  	line := s.peekPos()
  5541  	pos := base.Ctxt.PosTable.Pos(line)
  5542  	fl := funcLine{f: fn, base: pos.Base(), line: pos.Line()}
  5543  	bPanic := s.panics[fl]
  5544  	if bPanic == nil {
  5545  		bPanic = s.f.NewBlock(ssa.BlockPlain)
  5546  		s.panics[fl] = bPanic
  5547  		s.startBlock(bPanic)
  5548  		// The panic call takes/returns memory to ensure that the right
  5549  		// memory state is observed if the panic happens.
  5550  		s.rtcall(fn, false, nil)
  5551  	}
  5552  	b.AddEdgeTo(bNext)
  5553  	b.AddEdgeTo(bPanic)
  5554  	s.startBlock(bNext)
  5555  }
  5556  
  5557  func (s *state) intDivide(n ir.Node, a, b *ssa.Value) *ssa.Value {
  5558  	needcheck := true
  5559  	switch b.Op {
  5560  	case ssa.OpConst8, ssa.OpConst16, ssa.OpConst32, ssa.OpConst64:
  5561  		if b.AuxInt != 0 {
  5562  			needcheck = false
  5563  		}
  5564  	}
  5565  	if needcheck {
  5566  		// do a size-appropriate check for zero
  5567  		cmp := s.newValue2(s.ssaOp(ir.ONE, n.Type()), types.Types[types.TBOOL], b, s.zeroVal(n.Type()))
  5568  		s.check(cmp, ir.Syms.Panicdivide)
  5569  	}
  5570  	return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  5571  }
  5572  
  5573  // rtcall issues a call to the given runtime function fn with the listed args.
  5574  // Returns a slice of results of the given result types.
  5575  // The call is added to the end of the current block.
  5576  // If returns is false, the block is marked as an exit block.
  5577  func (s *state) rtcall(fn *obj.LSym, returns bool, results []*types.Type, args ...*ssa.Value) []*ssa.Value {
  5578  	s.prevCall = nil
  5579  	// Write args to the stack
  5580  	off := base.Ctxt.FixedFrameSize()
  5581  	var callArgs []*ssa.Value
  5582  	var callArgTypes []*types.Type
  5583  
  5584  	for _, arg := range args {
  5585  		t := arg.Type
  5586  		off = types.Rnd(off, t.Alignment())
  5587  		size := t.Size()
  5588  		callArgs = append(callArgs, arg)
  5589  		callArgTypes = append(callArgTypes, t)
  5590  		off += size
  5591  	}
  5592  	off = types.Rnd(off, int64(types.RegSize))
  5593  
  5594  	// Accumulate results types and offsets
  5595  	offR := off
  5596  	for _, t := range results {
  5597  		offR = types.Rnd(offR, t.Alignment())
  5598  		offR += t.Size()
  5599  	}
  5600  
  5601  	// Issue call
  5602  	var call *ssa.Value
  5603  	aux := ssa.StaticAuxCall(fn, s.f.ABIDefault.ABIAnalyzeTypes(nil, callArgTypes, results))
  5604  	callArgs = append(callArgs, s.mem())
  5605  	call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5606  	call.AddArgs(callArgs...)
  5607  	s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, int64(len(results)), call)
  5608  
  5609  	if !returns {
  5610  		// Finish block
  5611  		b := s.endBlock()
  5612  		b.Kind = ssa.BlockExit
  5613  		b.SetControl(call)
  5614  		call.AuxInt = off - base.Ctxt.FixedFrameSize()
  5615  		if len(results) > 0 {
  5616  			s.Fatalf("panic call can't have results")
  5617  		}
  5618  		return nil
  5619  	}
  5620  
  5621  	// Load results
  5622  	res := make([]*ssa.Value, len(results))
  5623  	for i, t := range results {
  5624  		off = types.Rnd(off, t.Alignment())
  5625  		res[i] = s.resultOfCall(call, int64(i), t)
  5626  		off += t.Size()
  5627  	}
  5628  	off = types.Rnd(off, int64(types.PtrSize))
  5629  
  5630  	// Remember how much callee stack space we needed.
  5631  	call.AuxInt = off
  5632  
  5633  	return res
  5634  }
  5635  
  5636  // do *left = right for type t.
  5637  func (s *state) storeType(t *types.Type, left, right *ssa.Value, skip skipMask, leftIsStmt bool) {
  5638  	s.instrument(t, left, instrumentWrite)
  5639  
  5640  	if skip == 0 && (!t.HasPointers() || ssa.IsStackAddr(left)) {
  5641  		// Known to not have write barrier. Store the whole type.
  5642  		s.vars[memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, left, right, s.mem(), leftIsStmt)
  5643  		return
  5644  	}
  5645  
  5646  	// store scalar fields first, so write barrier stores for
  5647  	// pointer fields can be grouped together, and scalar values
  5648  	// don't need to be live across the write barrier call.
  5649  	// TODO: if the writebarrier pass knows how to reorder stores,
  5650  	// we can do a single store here as long as skip==0.
  5651  	s.storeTypeScalars(t, left, right, skip)
  5652  	if skip&skipPtr == 0 && t.HasPointers() {
  5653  		s.storeTypePtrs(t, left, right)
  5654  	}
  5655  }
  5656  
  5657  // do *left = right for all scalar (non-pointer) parts of t.
  5658  func (s *state) storeTypeScalars(t *types.Type, left, right *ssa.Value, skip skipMask) {
  5659  	switch {
  5660  	case t.IsBoolean() || t.IsInteger() || t.IsFloat() || t.IsComplex():
  5661  		s.store(t, left, right)
  5662  	case t.IsPtrShaped():
  5663  		if t.IsPtr() && t.Elem().NotInHeap() {
  5664  			s.store(t, left, right) // see issue 42032
  5665  		}
  5666  		// otherwise, no scalar fields.
  5667  	case t.IsString():
  5668  		if skip&skipLen != 0 {
  5669  			return
  5670  		}
  5671  		len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], right)
  5672  		lenAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, s.config.PtrSize, left)
  5673  		s.store(types.Types[types.TINT], lenAddr, len)
  5674  	case t.IsSlice():
  5675  		if skip&skipLen == 0 {
  5676  			len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], right)
  5677  			lenAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, s.config.PtrSize, left)
  5678  			s.store(types.Types[types.TINT], lenAddr, len)
  5679  		}
  5680  		if skip&skipCap == 0 {
  5681  			cap := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], right)
  5682  			capAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, 2*s.config.PtrSize, left)
  5683  			s.store(types.Types[types.TINT], capAddr, cap)
  5684  		}
  5685  	case t.IsInterface():
  5686  		// itab field doesn't need a write barrier (even though it is a pointer).
  5687  		itab := s.newValue1(ssa.OpITab, s.f.Config.Types.BytePtr, right)
  5688  		s.store(types.Types[types.TUINTPTR], left, itab)
  5689  	case t.IsStruct():
  5690  		n := t.NumFields()
  5691  		for i := 0; i < n; i++ {
  5692  			ft := t.FieldType(i)
  5693  			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
  5694  			val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
  5695  			s.storeTypeScalars(ft, addr, val, 0)
  5696  		}
  5697  	case t.IsArray() && t.NumElem() == 0:
  5698  		// nothing
  5699  	case t.IsArray() && t.NumElem() == 1:
  5700  		s.storeTypeScalars(t.Elem(), left, s.newValue1I(ssa.OpArraySelect, t.Elem(), 0, right), 0)
  5701  	default:
  5702  		s.Fatalf("bad write barrier type %v", t)
  5703  	}
  5704  }
  5705  
  5706  // do *left = right for all pointer parts of t.
  5707  func (s *state) storeTypePtrs(t *types.Type, left, right *ssa.Value) {
  5708  	switch {
  5709  	case t.IsPtrShaped():
  5710  		if t.IsPtr() && t.Elem().NotInHeap() {
  5711  			break // see issue 42032
  5712  		}
  5713  		s.store(t, left, right)
  5714  	case t.IsString():
  5715  		ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, right)
  5716  		s.store(s.f.Config.Types.BytePtr, left, ptr)
  5717  	case t.IsSlice():
  5718  		elType := types.NewPtr(t.Elem())
  5719  		ptr := s.newValue1(ssa.OpSlicePtr, elType, right)
  5720  		s.store(elType, left, ptr)
  5721  	case t.IsInterface():
  5722  		// itab field is treated as a scalar.
  5723  		idata := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, right)
  5724  		idataAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.BytePtrPtr, s.config.PtrSize, left)
  5725  		s.store(s.f.Config.Types.BytePtr, idataAddr, idata)
  5726  	case t.IsStruct():
  5727  		n := t.NumFields()
  5728  		for i := 0; i < n; i++ {
  5729  			ft := t.FieldType(i)
  5730  			if !ft.HasPointers() {
  5731  				continue
  5732  			}
  5733  			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
  5734  			val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
  5735  			s.storeTypePtrs(ft, addr, val)
  5736  		}
  5737  	case t.IsArray() && t.NumElem() == 0:
  5738  		// nothing
  5739  	case t.IsArray() && t.NumElem() == 1:
  5740  		s.storeTypePtrs(t.Elem(), left, s.newValue1I(ssa.OpArraySelect, t.Elem(), 0, right))
  5741  	default:
  5742  		s.Fatalf("bad write barrier type %v", t)
  5743  	}
  5744  }
  5745  
  5746  // putArg evaluates n for the purpose of passing it as an argument to a function and returns the value for the call.
  5747  func (s *state) putArg(n ir.Node, t *types.Type) *ssa.Value {
  5748  	var a *ssa.Value
  5749  	if !TypeOK(t) {
  5750  		a = s.newValue2(ssa.OpDereference, t, s.addr(n), s.mem())
  5751  	} else {
  5752  		a = s.expr(n)
  5753  	}
  5754  	return a
  5755  }
  5756  
  5757  func (s *state) storeArgWithBase(n ir.Node, t *types.Type, base *ssa.Value, off int64) {
  5758  	pt := types.NewPtr(t)
  5759  	var addr *ssa.Value
  5760  	if base == s.sp {
  5761  		// Use special routine that avoids allocation on duplicate offsets.
  5762  		addr = s.constOffPtrSP(pt, off)
  5763  	} else {
  5764  		addr = s.newValue1I(ssa.OpOffPtr, pt, off, base)
  5765  	}
  5766  
  5767  	if !TypeOK(t) {
  5768  		a := s.addr(n)
  5769  		s.move(t, addr, a)
  5770  		return
  5771  	}
  5772  
  5773  	a := s.expr(n)
  5774  	s.storeType(t, addr, a, 0, false)
  5775  }
  5776  
  5777  // slice computes the slice v[i:j:k] and returns ptr, len, and cap of result.
  5778  // i,j,k may be nil, in which case they are set to their default value.
  5779  // v may be a slice, string or pointer to an array.
  5780  func (s *state) slice(v, i, j, k *ssa.Value, bounded bool) (p, l, c *ssa.Value) {
  5781  	t := v.Type
  5782  	var ptr, len, cap *ssa.Value
  5783  	switch {
  5784  	case t.IsSlice():
  5785  		ptr = s.newValue1(ssa.OpSlicePtr, types.NewPtr(t.Elem()), v)
  5786  		len = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
  5787  		cap = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], v)
  5788  	case t.IsString():
  5789  		ptr = s.newValue1(ssa.OpStringPtr, types.NewPtr(types.Types[types.TUINT8]), v)
  5790  		len = s.newValue1(ssa.OpStringLen, types.Types[types.TINT], v)
  5791  		cap = len
  5792  	case t.IsPtr():
  5793  		if !t.Elem().IsArray() {
  5794  			s.Fatalf("bad ptr to array in slice %v\n", t)
  5795  		}
  5796  		s.nilCheck(v)
  5797  		ptr = s.newValue1(ssa.OpCopy, types.NewPtr(t.Elem().Elem()), v)
  5798  		len = s.constInt(types.Types[types.TINT], t.Elem().NumElem())
  5799  		cap = len
  5800  	default:
  5801  		s.Fatalf("bad type in slice %v\n", t)
  5802  	}
  5803  
  5804  	// Set default values
  5805  	if i == nil {
  5806  		i = s.constInt(types.Types[types.TINT], 0)
  5807  	}
  5808  	if j == nil {
  5809  		j = len
  5810  	}
  5811  	three := true
  5812  	if k == nil {
  5813  		three = false
  5814  		k = cap
  5815  	}
  5816  
  5817  	// Panic if slice indices are not in bounds.
  5818  	// Make sure we check these in reverse order so that we're always
  5819  	// comparing against a value known to be nonnegative. See issue 28797.
  5820  	if three {
  5821  		if k != cap {
  5822  			kind := ssa.BoundsSlice3Alen
  5823  			if t.IsSlice() {
  5824  				kind = ssa.BoundsSlice3Acap
  5825  			}
  5826  			k = s.boundsCheck(k, cap, kind, bounded)
  5827  		}
  5828  		if j != k {
  5829  			j = s.boundsCheck(j, k, ssa.BoundsSlice3B, bounded)
  5830  		}
  5831  		i = s.boundsCheck(i, j, ssa.BoundsSlice3C, bounded)
  5832  	} else {
  5833  		if j != k {
  5834  			kind := ssa.BoundsSliceAlen
  5835  			if t.IsSlice() {
  5836  				kind = ssa.BoundsSliceAcap
  5837  			}
  5838  			j = s.boundsCheck(j, k, kind, bounded)
  5839  		}
  5840  		i = s.boundsCheck(i, j, ssa.BoundsSliceB, bounded)
  5841  	}
  5842  
  5843  	// Word-sized integer operations.
  5844  	subOp := s.ssaOp(ir.OSUB, types.Types[types.TINT])
  5845  	mulOp := s.ssaOp(ir.OMUL, types.Types[types.TINT])
  5846  	andOp := s.ssaOp(ir.OAND, types.Types[types.TINT])
  5847  
  5848  	// Calculate the length (rlen) and capacity (rcap) of the new slice.
  5849  	// For strings the capacity of the result is unimportant. However,
  5850  	// we use rcap to test if we've generated a zero-length slice.
  5851  	// Use length of strings for that.
  5852  	rlen := s.newValue2(subOp, types.Types[types.TINT], j, i)
  5853  	rcap := rlen
  5854  	if j != k && !t.IsString() {
  5855  		rcap = s.newValue2(subOp, types.Types[types.TINT], k, i)
  5856  	}
  5857  
  5858  	if (i.Op == ssa.OpConst64 || i.Op == ssa.OpConst32) && i.AuxInt == 0 {
  5859  		// No pointer arithmetic necessary.
  5860  		return ptr, rlen, rcap
  5861  	}
  5862  
  5863  	// Calculate the base pointer (rptr) for the new slice.
  5864  	//
  5865  	// Generate the following code assuming that indexes are in bounds.
  5866  	// The masking is to make sure that we don't generate a slice
  5867  	// that points to the next object in memory. We cannot just set
  5868  	// the pointer to nil because then we would create a nil slice or
  5869  	// string.
  5870  	//
  5871  	//     rcap = k - i
  5872  	//     rlen = j - i
  5873  	//     rptr = ptr + (mask(rcap) & (i * stride))
  5874  	//
  5875  	// Where mask(x) is 0 if x==0 and -1 if x>0 and stride is the width
  5876  	// of the element type.
  5877  	stride := s.constInt(types.Types[types.TINT], ptr.Type.Elem().Size())
  5878  
  5879  	// The delta is the number of bytes to offset ptr by.
  5880  	delta := s.newValue2(mulOp, types.Types[types.TINT], i, stride)
  5881  
  5882  	// If we're slicing to the point where the capacity is zero,
  5883  	// zero out the delta.
  5884  	mask := s.newValue1(ssa.OpSlicemask, types.Types[types.TINT], rcap)
  5885  	delta = s.newValue2(andOp, types.Types[types.TINT], delta, mask)
  5886  
  5887  	// Compute rptr = ptr + delta.
  5888  	rptr := s.newValue2(ssa.OpAddPtr, ptr.Type, ptr, delta)
  5889  
  5890  	return rptr, rlen, rcap
  5891  }
  5892  
  5893  type u642fcvtTab struct {
  5894  	leq, cvt2F, and, rsh, or, add ssa.Op
  5895  	one                           func(*state, *types.Type, int64) *ssa.Value
  5896  }
  5897  
  5898  var u64_f64 = u642fcvtTab{
  5899  	leq:   ssa.OpLeq64,
  5900  	cvt2F: ssa.OpCvt64to64F,
  5901  	and:   ssa.OpAnd64,
  5902  	rsh:   ssa.OpRsh64Ux64,
  5903  	or:    ssa.OpOr64,
  5904  	add:   ssa.OpAdd64F,
  5905  	one:   (*state).constInt64,
  5906  }
  5907  
  5908  var u64_f32 = u642fcvtTab{
  5909  	leq:   ssa.OpLeq64,
  5910  	cvt2F: ssa.OpCvt64to32F,
  5911  	and:   ssa.OpAnd64,
  5912  	rsh:   ssa.OpRsh64Ux64,
  5913  	or:    ssa.OpOr64,
  5914  	add:   ssa.OpAdd32F,
  5915  	one:   (*state).constInt64,
  5916  }
  5917  
  5918  func (s *state) uint64Tofloat64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5919  	return s.uint64Tofloat(&u64_f64, n, x, ft, tt)
  5920  }
  5921  
  5922  func (s *state) uint64Tofloat32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5923  	return s.uint64Tofloat(&u64_f32, n, x, ft, tt)
  5924  }
  5925  
  5926  func (s *state) uint64Tofloat(cvttab *u642fcvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5927  	// if x >= 0 {
  5928  	//    result = (floatY) x
  5929  	// } else {
  5930  	// 	  y = uintX(x) ; y = x & 1
  5931  	// 	  z = uintX(x) ; z = z >> 1
  5932  	// 	  z = z | y
  5933  	// 	  result = floatY(z)
  5934  	// 	  result = result + result
  5935  	// }
  5936  	//
  5937  	// Code borrowed from old code generator.
  5938  	// What's going on: large 64-bit "unsigned" looks like
  5939  	// negative number to hardware's integer-to-float
  5940  	// conversion. However, because the mantissa is only
  5941  	// 63 bits, we don't need the LSB, so instead we do an
  5942  	// unsigned right shift (divide by two), convert, and
  5943  	// double. However, before we do that, we need to be
  5944  	// sure that we do not lose a "1" if that made the
  5945  	// difference in the resulting rounding. Therefore, we
  5946  	// preserve it, and OR (not ADD) it back in. The case
  5947  	// that matters is when the eleven discarded bits are
  5948  	// equal to 10000000001; that rounds up, and the 1 cannot
  5949  	// be lost else it would round down if the LSB of the
  5950  	// candidate mantissa is 0.
  5951  	cmp := s.newValue2(cvttab.leq, types.Types[types.TBOOL], s.zeroVal(ft), x)
  5952  	b := s.endBlock()
  5953  	b.Kind = ssa.BlockIf
  5954  	b.SetControl(cmp)
  5955  	b.Likely = ssa.BranchLikely
  5956  
  5957  	bThen := s.f.NewBlock(ssa.BlockPlain)
  5958  	bElse := s.f.NewBlock(ssa.BlockPlain)
  5959  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  5960  
  5961  	b.AddEdgeTo(bThen)
  5962  	s.startBlock(bThen)
  5963  	a0 := s.newValue1(cvttab.cvt2F, tt, x)
  5964  	s.vars[n] = a0
  5965  	s.endBlock()
  5966  	bThen.AddEdgeTo(bAfter)
  5967  
  5968  	b.AddEdgeTo(bElse)
  5969  	s.startBlock(bElse)
  5970  	one := cvttab.one(s, ft, 1)
  5971  	y := s.newValue2(cvttab.and, ft, x, one)
  5972  	z := s.newValue2(cvttab.rsh, ft, x, one)
  5973  	z = s.newValue2(cvttab.or, ft, z, y)
  5974  	a := s.newValue1(cvttab.cvt2F, tt, z)
  5975  	a1 := s.newValue2(cvttab.add, tt, a, a)
  5976  	s.vars[n] = a1
  5977  	s.endBlock()
  5978  	bElse.AddEdgeTo(bAfter)
  5979  
  5980  	s.startBlock(bAfter)
  5981  	return s.variable(n, n.Type())
  5982  }
  5983  
  5984  type u322fcvtTab struct {
  5985  	cvtI2F, cvtF2F ssa.Op
  5986  }
  5987  
  5988  var u32_f64 = u322fcvtTab{
  5989  	cvtI2F: ssa.OpCvt32to64F,
  5990  	cvtF2F: ssa.OpCopy,
  5991  }
  5992  
  5993  var u32_f32 = u322fcvtTab{
  5994  	cvtI2F: ssa.OpCvt32to32F,
  5995  	cvtF2F: ssa.OpCvt64Fto32F,
  5996  }
  5997  
  5998  func (s *state) uint32Tofloat64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5999  	return s.uint32Tofloat(&u32_f64, n, x, ft, tt)
  6000  }
  6001  
  6002  func (s *state) uint32Tofloat32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6003  	return s.uint32Tofloat(&u32_f32, n, x, ft, tt)
  6004  }
  6005  
  6006  func (s *state) uint32Tofloat(cvttab *u322fcvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6007  	// if x >= 0 {
  6008  	// 	result = floatY(x)
  6009  	// } else {
  6010  	// 	result = floatY(float64(x) + (1<<32))
  6011  	// }
  6012  	cmp := s.newValue2(ssa.OpLeq32, types.Types[types.TBOOL], s.zeroVal(ft), x)
  6013  	b := s.endBlock()
  6014  	b.Kind = ssa.BlockIf
  6015  	b.SetControl(cmp)
  6016  	b.Likely = ssa.BranchLikely
  6017  
  6018  	bThen := s.f.NewBlock(ssa.BlockPlain)
  6019  	bElse := s.f.NewBlock(ssa.BlockPlain)
  6020  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  6021  
  6022  	b.AddEdgeTo(bThen)
  6023  	s.startBlock(bThen)
  6024  	a0 := s.newValue1(cvttab.cvtI2F, tt, x)
  6025  	s.vars[n] = a0
  6026  	s.endBlock()
  6027  	bThen.AddEdgeTo(bAfter)
  6028  
  6029  	b.AddEdgeTo(bElse)
  6030  	s.startBlock(bElse)
  6031  	a1 := s.newValue1(ssa.OpCvt32to64F, types.Types[types.TFLOAT64], x)
  6032  	twoToThe32 := s.constFloat64(types.Types[types.TFLOAT64], float64(1<<32))
  6033  	a2 := s.newValue2(ssa.OpAdd64F, types.Types[types.TFLOAT64], a1, twoToThe32)
  6034  	a3 := s.newValue1(cvttab.cvtF2F, tt, a2)
  6035  
  6036  	s.vars[n] = a3
  6037  	s.endBlock()
  6038  	bElse.AddEdgeTo(bAfter)
  6039  
  6040  	s.startBlock(bAfter)
  6041  	return s.variable(n, n.Type())
  6042  }
  6043  
  6044  // referenceTypeBuiltin generates code for the len/cap builtins for maps and channels.
  6045  func (s *state) referenceTypeBuiltin(n *ir.UnaryExpr, x *ssa.Value) *ssa.Value {
  6046  	if !n.X.Type().IsMap() && !n.X.Type().IsChan() {
  6047  		s.Fatalf("node must be a map or a channel")
  6048  	}
  6049  	// if n == nil {
  6050  	//   return 0
  6051  	// } else {
  6052  	//   // len
  6053  	//   return *((*int)n)
  6054  	//   // cap
  6055  	//   return *(((*int)n)+1)
  6056  	// }
  6057  	lenType := n.Type()
  6058  	nilValue := s.constNil(types.Types[types.TUINTPTR])
  6059  	cmp := s.newValue2(ssa.OpEqPtr, types.Types[types.TBOOL], x, nilValue)
  6060  	b := s.endBlock()
  6061  	b.Kind = ssa.BlockIf
  6062  	b.SetControl(cmp)
  6063  	b.Likely = ssa.BranchUnlikely
  6064  
  6065  	bThen := s.f.NewBlock(ssa.BlockPlain)
  6066  	bElse := s.f.NewBlock(ssa.BlockPlain)
  6067  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  6068  
  6069  	// length/capacity of a nil map/chan is zero
  6070  	b.AddEdgeTo(bThen)
  6071  	s.startBlock(bThen)
  6072  	s.vars[n] = s.zeroVal(lenType)
  6073  	s.endBlock()
  6074  	bThen.AddEdgeTo(bAfter)
  6075  
  6076  	b.AddEdgeTo(bElse)
  6077  	s.startBlock(bElse)
  6078  	switch n.Op() {
  6079  	case ir.OLEN:
  6080  		// length is stored in the first word for map/chan
  6081  		s.vars[n] = s.load(lenType, x)
  6082  	case ir.OCAP:
  6083  		// capacity is stored in the second word for chan
  6084  		sw := s.newValue1I(ssa.OpOffPtr, lenType.PtrTo(), lenType.Size(), x)
  6085  		s.vars[n] = s.load(lenType, sw)
  6086  	default:
  6087  		s.Fatalf("op must be OLEN or OCAP")
  6088  	}
  6089  	s.endBlock()
  6090  	bElse.AddEdgeTo(bAfter)
  6091  
  6092  	s.startBlock(bAfter)
  6093  	return s.variable(n, lenType)
  6094  }
  6095  
  6096  type f2uCvtTab struct {
  6097  	ltf, cvt2U, subf, or ssa.Op
  6098  	floatValue           func(*state, *types.Type, float64) *ssa.Value
  6099  	intValue             func(*state, *types.Type, int64) *ssa.Value
  6100  	cutoff               uint64
  6101  }
  6102  
  6103  var f32_u64 = f2uCvtTab{
  6104  	ltf:        ssa.OpLess32F,
  6105  	cvt2U:      ssa.OpCvt32Fto64,
  6106  	subf:       ssa.OpSub32F,
  6107  	or:         ssa.OpOr64,
  6108  	floatValue: (*state).constFloat32,
  6109  	intValue:   (*state).constInt64,
  6110  	cutoff:     1 << 63,
  6111  }
  6112  
  6113  var f64_u64 = f2uCvtTab{
  6114  	ltf:        ssa.OpLess64F,
  6115  	cvt2U:      ssa.OpCvt64Fto64,
  6116  	subf:       ssa.OpSub64F,
  6117  	or:         ssa.OpOr64,
  6118  	floatValue: (*state).constFloat64,
  6119  	intValue:   (*state).constInt64,
  6120  	cutoff:     1 << 63,
  6121  }
  6122  
  6123  var f32_u32 = f2uCvtTab{
  6124  	ltf:        ssa.OpLess32F,
  6125  	cvt2U:      ssa.OpCvt32Fto32,
  6126  	subf:       ssa.OpSub32F,
  6127  	or:         ssa.OpOr32,
  6128  	floatValue: (*state).constFloat32,
  6129  	intValue:   func(s *state, t *types.Type, v int64) *ssa.Value { return s.constInt32(t, int32(v)) },
  6130  	cutoff:     1 << 31,
  6131  }
  6132  
  6133  var f64_u32 = f2uCvtTab{
  6134  	ltf:        ssa.OpLess64F,
  6135  	cvt2U:      ssa.OpCvt64Fto32,
  6136  	subf:       ssa.OpSub64F,
  6137  	or:         ssa.OpOr32,
  6138  	floatValue: (*state).constFloat64,
  6139  	intValue:   func(s *state, t *types.Type, v int64) *ssa.Value { return s.constInt32(t, int32(v)) },
  6140  	cutoff:     1 << 31,
  6141  }
  6142  
  6143  func (s *state) float32ToUint64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6144  	return s.floatToUint(&f32_u64, n, x, ft, tt)
  6145  }
  6146  func (s *state) float64ToUint64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6147  	return s.floatToUint(&f64_u64, n, x, ft, tt)
  6148  }
  6149  
  6150  func (s *state) float32ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6151  	return s.floatToUint(&f32_u32, n, x, ft, tt)
  6152  }
  6153  
  6154  func (s *state) float64ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6155  	return s.floatToUint(&f64_u32, n, x, ft, tt)
  6156  }
  6157  
  6158  func (s *state) floatToUint(cvttab *f2uCvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6159  	// cutoff:=1<<(intY_Size-1)
  6160  	// if x < floatX(cutoff) {
  6161  	// 	result = uintY(x)
  6162  	// } else {
  6163  	// 	y = x - floatX(cutoff)
  6164  	// 	z = uintY(y)
  6165  	// 	result = z | -(cutoff)
  6166  	// }
  6167  	cutoff := cvttab.floatValue(s, ft, float64(cvttab.cutoff))
  6168  	cmp := s.newValue2(cvttab.ltf, types.Types[types.TBOOL], x, cutoff)
  6169  	b := s.endBlock()
  6170  	b.Kind = ssa.BlockIf
  6171  	b.SetControl(cmp)
  6172  	b.Likely = ssa.BranchLikely
  6173  
  6174  	bThen := s.f.NewBlock(ssa.BlockPlain)
  6175  	bElse := s.f.NewBlock(ssa.BlockPlain)
  6176  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  6177  
  6178  	b.AddEdgeTo(bThen)
  6179  	s.startBlock(bThen)
  6180  	a0 := s.newValue1(cvttab.cvt2U, tt, x)
  6181  	s.vars[n] = a0
  6182  	s.endBlock()
  6183  	bThen.AddEdgeTo(bAfter)
  6184  
  6185  	b.AddEdgeTo(bElse)
  6186  	s.startBlock(bElse)
  6187  	y := s.newValue2(cvttab.subf, ft, x, cutoff)
  6188  	y = s.newValue1(cvttab.cvt2U, tt, y)
  6189  	z := cvttab.intValue(s, tt, int64(-cvttab.cutoff))
  6190  	a1 := s.newValue2(cvttab.or, tt, y, z)
  6191  	s.vars[n] = a1
  6192  	s.endBlock()
  6193  	bElse.AddEdgeTo(bAfter)
  6194  
  6195  	s.startBlock(bAfter)
  6196  	return s.variable(n, n.Type())
  6197  }
  6198  
  6199  // dottype generates SSA for a type assertion node.
  6200  // commaok indicates whether to panic or return a bool.
  6201  // If commaok is false, resok will be nil.
  6202  func (s *state) dottype(n *ir.TypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
  6203  	iface := s.expr(n.X)              // input interface
  6204  	target := s.reflectType(n.Type()) // target type
  6205  	var targetItab *ssa.Value
  6206  	if n.Itab != nil {
  6207  		targetItab = s.expr(n.Itab)
  6208  	}
  6209  	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, target, targetItab, commaok)
  6210  }
  6211  
  6212  func (s *state) dynamicDottype(n *ir.DynamicTypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
  6213  	iface := s.expr(n.X)
  6214  	target := s.expr(n.T)
  6215  	var itab *ssa.Value
  6216  	if !n.X.Type().IsEmptyInterface() && !n.Type().IsInterface() {
  6217  		byteptr := s.f.Config.Types.BytePtr
  6218  		itab = target
  6219  		target = s.load(byteptr, s.newValue1I(ssa.OpOffPtr, byteptr, int64(types.PtrSize), itab)) // itab.typ
  6220  	}
  6221  	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, target, itab, commaok)
  6222  }
  6223  
  6224  // dottype1 implements a x.(T) operation. iface is the argument (x), dst is the type we're asserting to (T)
  6225  // and src is the type we're asserting from.
  6226  // target is the *runtime._type of dst.
  6227  // If src is a nonempty interface and dst is not an interface, targetItab is an itab representing (dst, src). Otherwise it is nil.
  6228  // commaok is true if the caller wants a boolean success value. Otherwise, the generated code panics if the conversion fails.
  6229  func (s *state) dottype1(pos src.XPos, src, dst *types.Type, iface, target, targetItab *ssa.Value, commaok bool) (res, resok *ssa.Value) {
  6230  	byteptr := s.f.Config.Types.BytePtr
  6231  	if dst.IsInterface() {
  6232  		if dst.IsEmptyInterface() {
  6233  			// Converting to an empty interface.
  6234  			// Input could be an empty or nonempty interface.
  6235  			if base.Debug.TypeAssert > 0 {
  6236  				base.WarnfAt(pos, "type assertion inlined")
  6237  			}
  6238  
  6239  			// Get itab/type field from input.
  6240  			itab := s.newValue1(ssa.OpITab, byteptr, iface)
  6241  			// Conversion succeeds iff that field is not nil.
  6242  			cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6243  
  6244  			if src.IsEmptyInterface() && commaok {
  6245  				// Converting empty interface to empty interface with ,ok is just a nil check.
  6246  				return iface, cond
  6247  			}
  6248  
  6249  			// Branch on nilness.
  6250  			b := s.endBlock()
  6251  			b.Kind = ssa.BlockIf
  6252  			b.SetControl(cond)
  6253  			b.Likely = ssa.BranchLikely
  6254  			bOk := s.f.NewBlock(ssa.BlockPlain)
  6255  			bFail := s.f.NewBlock(ssa.BlockPlain)
  6256  			b.AddEdgeTo(bOk)
  6257  			b.AddEdgeTo(bFail)
  6258  
  6259  			if !commaok {
  6260  				// On failure, panic by calling panicnildottype.
  6261  				s.startBlock(bFail)
  6262  				s.rtcall(ir.Syms.Panicnildottype, false, nil, target)
  6263  
  6264  				// On success, return (perhaps modified) input interface.
  6265  				s.startBlock(bOk)
  6266  				if src.IsEmptyInterface() {
  6267  					res = iface // Use input interface unchanged.
  6268  					return
  6269  				}
  6270  				// Load type out of itab, build interface with existing idata.
  6271  				off := s.newValue1I(ssa.OpOffPtr, byteptr, int64(types.PtrSize), itab)
  6272  				typ := s.load(byteptr, off)
  6273  				idata := s.newValue1(ssa.OpIData, byteptr, iface)
  6274  				res = s.newValue2(ssa.OpIMake, dst, typ, idata)
  6275  				return
  6276  			}
  6277  
  6278  			s.startBlock(bOk)
  6279  			// nonempty -> empty
  6280  			// Need to load type from itab
  6281  			off := s.newValue1I(ssa.OpOffPtr, byteptr, int64(types.PtrSize), itab)
  6282  			s.vars[typVar] = s.load(byteptr, off)
  6283  			s.endBlock()
  6284  
  6285  			// itab is nil, might as well use that as the nil result.
  6286  			s.startBlock(bFail)
  6287  			s.vars[typVar] = itab
  6288  			s.endBlock()
  6289  
  6290  			// Merge point.
  6291  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  6292  			bOk.AddEdgeTo(bEnd)
  6293  			bFail.AddEdgeTo(bEnd)
  6294  			s.startBlock(bEnd)
  6295  			idata := s.newValue1(ssa.OpIData, byteptr, iface)
  6296  			res = s.newValue2(ssa.OpIMake, dst, s.variable(typVar, byteptr), idata)
  6297  			resok = cond
  6298  			delete(s.vars, typVar)
  6299  			return
  6300  		}
  6301  		// converting to a nonempty interface needs a runtime call.
  6302  		if base.Debug.TypeAssert > 0 {
  6303  			base.WarnfAt(pos, "type assertion not inlined")
  6304  		}
  6305  		if !commaok {
  6306  			fn := ir.Syms.AssertI2I
  6307  			if src.IsEmptyInterface() {
  6308  				fn = ir.Syms.AssertE2I
  6309  			}
  6310  			data := s.newValue1(ssa.OpIData, types.Types[types.TUNSAFEPTR], iface)
  6311  			tab := s.newValue1(ssa.OpITab, byteptr, iface)
  6312  			tab = s.rtcall(fn, true, []*types.Type{byteptr}, target, tab)[0]
  6313  			return s.newValue2(ssa.OpIMake, dst, tab, data), nil
  6314  		}
  6315  		fn := ir.Syms.AssertI2I2
  6316  		if src.IsEmptyInterface() {
  6317  			fn = ir.Syms.AssertE2I2
  6318  		}
  6319  		res = s.rtcall(fn, true, []*types.Type{dst}, target, iface)[0]
  6320  		resok = s.newValue2(ssa.OpNeqInter, types.Types[types.TBOOL], res, s.constInterface(dst))
  6321  		return
  6322  	}
  6323  
  6324  	if base.Debug.TypeAssert > 0 {
  6325  		base.WarnfAt(pos, "type assertion inlined")
  6326  	}
  6327  
  6328  	// Converting to a concrete type.
  6329  	direct := types.IsDirectIface(dst)
  6330  	itab := s.newValue1(ssa.OpITab, byteptr, iface) // type word of interface
  6331  	if base.Debug.TypeAssert > 0 {
  6332  		base.WarnfAt(pos, "type assertion inlined")
  6333  	}
  6334  	var wantedFirstWord *ssa.Value
  6335  	if src.IsEmptyInterface() {
  6336  		// Looking for pointer to target type.
  6337  		wantedFirstWord = target
  6338  	} else {
  6339  		// Looking for pointer to itab for target type and source interface.
  6340  		wantedFirstWord = targetItab
  6341  	}
  6342  
  6343  	var tmp ir.Node     // temporary for use with large types
  6344  	var addr *ssa.Value // address of tmp
  6345  	if commaok && !TypeOK(dst) {
  6346  		// unSSAable type, use temporary.
  6347  		// TODO: get rid of some of these temporaries.
  6348  		tmp, addr = s.temp(pos, dst)
  6349  	}
  6350  
  6351  	cond := s.newValue2(ssa.OpEqPtr, types.Types[types.TBOOL], itab, wantedFirstWord)
  6352  	b := s.endBlock()
  6353  	b.Kind = ssa.BlockIf
  6354  	b.SetControl(cond)
  6355  	b.Likely = ssa.BranchLikely
  6356  
  6357  	bOk := s.f.NewBlock(ssa.BlockPlain)
  6358  	bFail := s.f.NewBlock(ssa.BlockPlain)
  6359  	b.AddEdgeTo(bOk)
  6360  	b.AddEdgeTo(bFail)
  6361  
  6362  	if !commaok {
  6363  		// on failure, panic by calling panicdottype
  6364  		s.startBlock(bFail)
  6365  		taddr := s.reflectType(src)
  6366  		if src.IsEmptyInterface() {
  6367  			s.rtcall(ir.Syms.PanicdottypeE, false, nil, itab, target, taddr)
  6368  		} else {
  6369  			s.rtcall(ir.Syms.PanicdottypeI, false, nil, itab, target, taddr)
  6370  		}
  6371  
  6372  		// on success, return data from interface
  6373  		s.startBlock(bOk)
  6374  		if direct {
  6375  			return s.newValue1(ssa.OpIData, dst, iface), nil
  6376  		}
  6377  		p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6378  		return s.load(dst, p), nil
  6379  	}
  6380  
  6381  	// commaok is the more complicated case because we have
  6382  	// a control flow merge point.
  6383  	bEnd := s.f.NewBlock(ssa.BlockPlain)
  6384  	// Note that we need a new valVar each time (unlike okVar where we can
  6385  	// reuse the variable) because it might have a different type every time.
  6386  	valVar := ssaMarker("val")
  6387  
  6388  	// type assertion succeeded
  6389  	s.startBlock(bOk)
  6390  	if tmp == nil {
  6391  		if direct {
  6392  			s.vars[valVar] = s.newValue1(ssa.OpIData, dst, iface)
  6393  		} else {
  6394  			p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6395  			s.vars[valVar] = s.load(dst, p)
  6396  		}
  6397  	} else {
  6398  		p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6399  		s.move(dst, addr, p)
  6400  	}
  6401  	s.vars[okVar] = s.constBool(true)
  6402  	s.endBlock()
  6403  	bOk.AddEdgeTo(bEnd)
  6404  
  6405  	// type assertion failed
  6406  	s.startBlock(bFail)
  6407  	if tmp == nil {
  6408  		s.vars[valVar] = s.zeroVal(dst)
  6409  	} else {
  6410  		s.zero(dst, addr)
  6411  	}
  6412  	s.vars[okVar] = s.constBool(false)
  6413  	s.endBlock()
  6414  	bFail.AddEdgeTo(bEnd)
  6415  
  6416  	// merge point
  6417  	s.startBlock(bEnd)
  6418  	if tmp == nil {
  6419  		res = s.variable(valVar, dst)
  6420  		delete(s.vars, valVar)
  6421  	} else {
  6422  		res = s.load(dst, addr)
  6423  		s.vars[memVar] = s.newValue1A(ssa.OpVarKill, types.TypeMem, tmp.(*ir.Name), s.mem())
  6424  	}
  6425  	resok = s.variable(okVar, types.Types[types.TBOOL])
  6426  	delete(s.vars, okVar)
  6427  	return res, resok
  6428  }
  6429  
  6430  // temp allocates a temp of type t at position pos
  6431  func (s *state) temp(pos src.XPos, t *types.Type) (*ir.Name, *ssa.Value) {
  6432  	tmp := typecheck.TempAt(pos, s.curfn, t)
  6433  	s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, tmp, s.mem())
  6434  	addr := s.addr(tmp)
  6435  	return tmp, addr
  6436  }
  6437  
  6438  // variable returns the value of a variable at the current location.
  6439  func (s *state) variable(n ir.Node, t *types.Type) *ssa.Value {
  6440  	v := s.vars[n]
  6441  	if v != nil {
  6442  		return v
  6443  	}
  6444  	v = s.fwdVars[n]
  6445  	if v != nil {
  6446  		return v
  6447  	}
  6448  
  6449  	if s.curBlock == s.f.Entry {
  6450  		// No variable should be live at entry.
  6451  		s.Fatalf("Value live at entry. It shouldn't be. func %s, node %v, value %v", s.f.Name, n, v)
  6452  	}
  6453  	// Make a FwdRef, which records a value that's live on block input.
  6454  	// We'll find the matching definition as part of insertPhis.
  6455  	v = s.newValue0A(ssa.OpFwdRef, t, fwdRefAux{N: n})
  6456  	s.fwdVars[n] = v
  6457  	if n.Op() == ir.ONAME {
  6458  		s.addNamedValue(n.(*ir.Name), v)
  6459  	}
  6460  	return v
  6461  }
  6462  
  6463  func (s *state) mem() *ssa.Value {
  6464  	return s.variable(memVar, types.TypeMem)
  6465  }
  6466  
  6467  func (s *state) addNamedValue(n *ir.Name, v *ssa.Value) {
  6468  	if n.Class == ir.Pxxx {
  6469  		// Don't track our marker nodes (memVar etc.).
  6470  		return
  6471  	}
  6472  	if ir.IsAutoTmp(n) {
  6473  		// Don't track temporary variables.
  6474  		return
  6475  	}
  6476  	if n.Class == ir.PPARAMOUT {
  6477  		// Don't track named output values.  This prevents return values
  6478  		// from being assigned too early. See #14591 and #14762. TODO: allow this.
  6479  		return
  6480  	}
  6481  	loc := ssa.LocalSlot{N: n, Type: n.Type(), Off: 0}
  6482  	values, ok := s.f.NamedValues[loc]
  6483  	if !ok {
  6484  		s.f.Names = append(s.f.Names, &loc)
  6485  		s.f.CanonicalLocalSlots[loc] = &loc
  6486  	}
  6487  	s.f.NamedValues[loc] = append(values, v)
  6488  }
  6489  
  6490  // Branch is an unresolved branch.
  6491  type Branch struct {
  6492  	P *obj.Prog  // branch instruction
  6493  	B *ssa.Block // target
  6494  }
  6495  
  6496  // State contains state needed during Prog generation.
  6497  type State struct {
  6498  	ABI obj.ABI
  6499  
  6500  	pp *objw.Progs
  6501  
  6502  	// Branches remembers all the branch instructions we've seen
  6503  	// and where they would like to go.
  6504  	Branches []Branch
  6505  
  6506  	// bstart remembers where each block starts (indexed by block ID)
  6507  	bstart []*obj.Prog
  6508  
  6509  	maxarg int64 // largest frame size for arguments to calls made by the function
  6510  
  6511  	// Map from GC safe points to liveness index, generated by
  6512  	// liveness analysis.
  6513  	livenessMap liveness.Map
  6514  
  6515  	// partLiveArgs includes arguments that may be partially live, for which we
  6516  	// need to generate instructions that spill the argument registers.
  6517  	partLiveArgs map[*ir.Name]bool
  6518  
  6519  	// lineRunStart records the beginning of the current run of instructions
  6520  	// within a single block sharing the same line number
  6521  	// Used to move statement marks to the beginning of such runs.
  6522  	lineRunStart *obj.Prog
  6523  
  6524  	// wasm: The number of values on the WebAssembly stack. This is only used as a safeguard.
  6525  	OnWasmStackSkipped int
  6526  }
  6527  
  6528  func (s *State) FuncInfo() *obj.FuncInfo {
  6529  	return s.pp.CurFunc.LSym.Func()
  6530  }
  6531  
  6532  // Prog appends a new Prog.
  6533  func (s *State) Prog(as obj.As) *obj.Prog {
  6534  	p := s.pp.Prog(as)
  6535  	if objw.LosesStmtMark(as) {
  6536  		return p
  6537  	}
  6538  	// Float a statement start to the beginning of any same-line run.
  6539  	// lineRunStart is reset at block boundaries, which appears to work well.
  6540  	if s.lineRunStart == nil || s.lineRunStart.Pos.Line() != p.Pos.Line() {
  6541  		s.lineRunStart = p
  6542  	} else if p.Pos.IsStmt() == src.PosIsStmt {
  6543  		s.lineRunStart.Pos = s.lineRunStart.Pos.WithIsStmt()
  6544  		p.Pos = p.Pos.WithNotStmt()
  6545  	}
  6546  	return p
  6547  }
  6548  
  6549  // Pc returns the current Prog.
  6550  func (s *State) Pc() *obj.Prog {
  6551  	return s.pp.Next
  6552  }
  6553  
  6554  // SetPos sets the current source position.
  6555  func (s *State) SetPos(pos src.XPos) {
  6556  	s.pp.Pos = pos
  6557  }
  6558  
  6559  // Br emits a single branch instruction and returns the instruction.
  6560  // Not all architectures need the returned instruction, but otherwise
  6561  // the boilerplate is common to all.
  6562  func (s *State) Br(op obj.As, target *ssa.Block) *obj.Prog {
  6563  	p := s.Prog(op)
  6564  	p.To.Type = obj.TYPE_BRANCH
  6565  	s.Branches = append(s.Branches, Branch{P: p, B: target})
  6566  	return p
  6567  }
  6568  
  6569  // DebugFriendlySetPosFrom adjusts Pos.IsStmt subject to heuristics
  6570  // that reduce "jumpy" line number churn when debugging.
  6571  // Spill/fill/copy instructions from the register allocator,
  6572  // phi functions, and instructions with a no-pos position
  6573  // are examples of instructions that can cause churn.
  6574  func (s *State) DebugFriendlySetPosFrom(v *ssa.Value) {
  6575  	switch v.Op {
  6576  	case ssa.OpPhi, ssa.OpCopy, ssa.OpLoadReg, ssa.OpStoreReg:
  6577  		// These are not statements
  6578  		s.SetPos(v.Pos.WithNotStmt())
  6579  	default:
  6580  		p := v.Pos
  6581  		if p != src.NoXPos {
  6582  			// If the position is defined, update the position.
  6583  			// Also convert default IsStmt to NotStmt; only
  6584  			// explicit statement boundaries should appear
  6585  			// in the generated code.
  6586  			if p.IsStmt() != src.PosIsStmt {
  6587  				if s.pp.Pos.IsStmt() == src.PosIsStmt && s.pp.Pos.SameFileAndLine(p) {
  6588  					// If s.pp.Pos already has a statement mark, then it was set here (below) for
  6589  					// the previous value.  If an actual instruction had been emitted for that
  6590  					// value, then the statement mark would have been reset.  Since the statement
  6591  					// mark of s.pp.Pos was not reset, this position (file/line) still needs a
  6592  					// statement mark on an instruction.  If file and line for this value are
  6593  					// the same as the previous value, then the first instruction for this
  6594  					// value will work to take the statement mark.  Return early to avoid
  6595  					// resetting the statement mark.
  6596  					//
  6597  					// The reset of s.pp.Pos occurs in (*Progs).Prog() -- if it emits
  6598  					// an instruction, and the instruction's statement mark was set,
  6599  					// and it is not one of the LosesStmtMark instructions,
  6600  					// then Prog() resets the statement mark on the (*Progs).Pos.
  6601  					return
  6602  				}
  6603  				p = p.WithNotStmt()
  6604  				// Calls use the pos attached to v, but copy the statement mark from State
  6605  			}
  6606  			s.SetPos(p)
  6607  		} else {
  6608  			s.SetPos(s.pp.Pos.WithNotStmt())
  6609  		}
  6610  	}
  6611  }
  6612  
  6613  // emit argument info (locations on stack) for traceback.
  6614  func emitArgInfo(e *ssafn, f *ssa.Func, pp *objw.Progs) {
  6615  	ft := e.curfn.Type()
  6616  	if ft.NumRecvs() == 0 && ft.NumParams() == 0 {
  6617  		return
  6618  	}
  6619  
  6620  	x := EmitArgInfo(e.curfn, f.OwnAux.ABIInfo())
  6621  	x.Set(obj.AttrContentAddressable, true)
  6622  	e.curfn.LSym.Func().ArgInfo = x
  6623  
  6624  	// Emit a funcdata pointing at the arg info data.
  6625  	p := pp.Prog(obj.AFUNCDATA)
  6626  	p.From.SetConst(objabi.FUNCDATA_ArgInfo)
  6627  	p.To.Type = obj.TYPE_MEM
  6628  	p.To.Name = obj.NAME_EXTERN
  6629  	p.To.Sym = x
  6630  }
  6631  
  6632  // emit argument info (locations on stack) of f for traceback.
  6633  func EmitArgInfo(f *ir.Func, abiInfo *abi.ABIParamResultInfo) *obj.LSym {
  6634  	x := base.Ctxt.Lookup(fmt.Sprintf("%s.arginfo%d", f.LSym.Name, f.ABI))
  6635  	// NOTE: do not set ContentAddressable here. This may be referenced from
  6636  	// assembly code by name (in this case f is a declaration).
  6637  	// Instead, set it in emitArgInfo above.
  6638  
  6639  	PtrSize := int64(types.PtrSize)
  6640  	uintptrTyp := types.Types[types.TUINTPTR]
  6641  
  6642  	isAggregate := func(t *types.Type) bool {
  6643  		return t.IsStruct() || t.IsArray() || t.IsComplex() || t.IsInterface() || t.IsString() || t.IsSlice()
  6644  	}
  6645  
  6646  	// Populate the data.
  6647  	// The data is a stream of bytes, which contains the offsets and sizes of the
  6648  	// non-aggregate arguments or non-aggregate fields/elements of aggregate-typed
  6649  	// arguments, along with special "operators". Specifically,
  6650  	// - for each non-aggrgate arg/field/element, its offset from FP (1 byte) and
  6651  	//   size (1 byte)
  6652  	// - special operators:
  6653  	//   - 0xff - end of sequence
  6654  	//   - 0xfe - print { (at the start of an aggregate-typed argument)
  6655  	//   - 0xfd - print } (at the end of an aggregate-typed argument)
  6656  	//   - 0xfc - print ... (more args/fields/elements)
  6657  	//   - 0xfb - print _ (offset too large)
  6658  	// These constants need to be in sync with runtime.traceback.go:printArgs.
  6659  	const (
  6660  		_endSeq         = 0xff
  6661  		_startAgg       = 0xfe
  6662  		_endAgg         = 0xfd
  6663  		_dotdotdot      = 0xfc
  6664  		_offsetTooLarge = 0xfb
  6665  		_special        = 0xf0 // above this are operators, below this are ordinary offsets
  6666  	)
  6667  
  6668  	const (
  6669  		limit    = 10 // print no more than 10 args/components
  6670  		maxDepth = 5  // no more than 5 layers of nesting
  6671  
  6672  		// maxLen is a (conservative) upper bound of the byte stream length. For
  6673  		// each arg/component, it has no more than 2 bytes of data (size, offset),
  6674  		// and no more than one {, }, ... at each level (it cannot have both the
  6675  		// data and ... unless it is the last one, just be conservative). Plus 1
  6676  		// for _endSeq.
  6677  		maxLen = (maxDepth*3+2)*limit + 1
  6678  	)
  6679  
  6680  	wOff := 0
  6681  	n := 0
  6682  	writebyte := func(o uint8) { wOff = objw.Uint8(x, wOff, o) }
  6683  
  6684  	// Write one non-aggrgate arg/field/element.
  6685  	write1 := func(sz, offset int64) {
  6686  		if offset >= _special {
  6687  			writebyte(_offsetTooLarge)
  6688  		} else {
  6689  			writebyte(uint8(offset))
  6690  			writebyte(uint8(sz))
  6691  		}
  6692  		n++
  6693  	}
  6694  
  6695  	// Visit t recursively and write it out.
  6696  	// Returns whether to continue visiting.
  6697  	var visitType func(baseOffset int64, t *types.Type, depth int) bool
  6698  	visitType = func(baseOffset int64, t *types.Type, depth int) bool {
  6699  		if n >= limit {
  6700  			writebyte(_dotdotdot)
  6701  			return false
  6702  		}
  6703  		if !isAggregate(t) {
  6704  			write1(t.Size(), baseOffset)
  6705  			return true
  6706  		}
  6707  		writebyte(_startAgg)
  6708  		depth++
  6709  		if depth >= maxDepth {
  6710  			writebyte(_dotdotdot)
  6711  			writebyte(_endAgg)
  6712  			n++
  6713  			return true
  6714  		}
  6715  		switch {
  6716  		case t.IsInterface(), t.IsString():
  6717  			_ = visitType(baseOffset, uintptrTyp, depth) &&
  6718  				visitType(baseOffset+PtrSize, uintptrTyp, depth)
  6719  		case t.IsSlice():
  6720  			_ = visitType(baseOffset, uintptrTyp, depth) &&
  6721  				visitType(baseOffset+PtrSize, uintptrTyp, depth) &&
  6722  				visitType(baseOffset+PtrSize*2, uintptrTyp, depth)
  6723  		case t.IsComplex():
  6724  			_ = visitType(baseOffset, types.FloatForComplex(t), depth) &&
  6725  				visitType(baseOffset+t.Size()/2, types.FloatForComplex(t), depth)
  6726  		case t.IsArray():
  6727  			if t.NumElem() == 0 {
  6728  				n++ // {} counts as a component
  6729  				break
  6730  			}
  6731  			for i := int64(0); i < t.NumElem(); i++ {
  6732  				if !visitType(baseOffset, t.Elem(), depth) {
  6733  					break
  6734  				}
  6735  				baseOffset += t.Elem().Size()
  6736  			}
  6737  		case t.IsStruct():
  6738  			if t.NumFields() == 0 {
  6739  				n++ // {} counts as a component
  6740  				break
  6741  			}
  6742  			for _, field := range t.Fields().Slice() {
  6743  				if !visitType(baseOffset+field.Offset, field.Type, depth) {
  6744  					break
  6745  				}
  6746  			}
  6747  		}
  6748  		writebyte(_endAgg)
  6749  		return true
  6750  	}
  6751  
  6752  	start := 0
  6753  	if strings.Contains(f.LSym.Name, "[") {
  6754  		// Skip the dictionary argument - it is implicit and the user doesn't need to see it.
  6755  		start = 1
  6756  	}
  6757  
  6758  	for _, a := range abiInfo.InParams()[start:] {
  6759  		if !visitType(a.FrameOffset(abiInfo), a.Type, 0) {
  6760  			break
  6761  		}
  6762  	}
  6763  	writebyte(_endSeq)
  6764  	if wOff > maxLen {
  6765  		base.Fatalf("ArgInfo too large")
  6766  	}
  6767  
  6768  	return x
  6769  }
  6770  
  6771  // for wrapper, emit info of wrapped function.
  6772  func emitWrappedFuncInfo(e *ssafn, pp *objw.Progs) {
  6773  	if base.Ctxt.Flag_linkshared {
  6774  		// Relative reference (SymPtrOff) to another shared object doesn't work.
  6775  		// Unfortunate.
  6776  		return
  6777  	}
  6778  
  6779  	wfn := e.curfn.WrappedFunc
  6780  	if wfn == nil {
  6781  		return
  6782  	}
  6783  
  6784  	wsym := wfn.Linksym()
  6785  	x := base.Ctxt.LookupInit(fmt.Sprintf("%s.wrapinfo", wsym.Name), func(x *obj.LSym) {
  6786  		objw.SymPtrOff(x, 0, wsym)
  6787  		x.Set(obj.AttrContentAddressable, true)
  6788  	})
  6789  	e.curfn.LSym.Func().WrapInfo = x
  6790  
  6791  	// Emit a funcdata pointing at the wrap info data.
  6792  	p := pp.Prog(obj.AFUNCDATA)
  6793  	p.From.SetConst(objabi.FUNCDATA_WrapInfo)
  6794  	p.To.Type = obj.TYPE_MEM
  6795  	p.To.Name = obj.NAME_EXTERN
  6796  	p.To.Sym = x
  6797  }
  6798  
  6799  // genssa appends entries to pp for each instruction in f.
  6800  func genssa(f *ssa.Func, pp *objw.Progs) {
  6801  	var s State
  6802  	s.ABI = f.OwnAux.Fn.ABI()
  6803  
  6804  	e := f.Frontend().(*ssafn)
  6805  
  6806  	s.livenessMap, s.partLiveArgs = liveness.Compute(e.curfn, f, e.stkptrsize, pp)
  6807  	emitArgInfo(e, f, pp)
  6808  	argLiveBlockMap, argLiveValueMap := liveness.ArgLiveness(e.curfn, f, pp)
  6809  
  6810  	openDeferInfo := e.curfn.LSym.Func().OpenCodedDeferInfo
  6811  	if openDeferInfo != nil {
  6812  		// This function uses open-coded defers -- write out the funcdata
  6813  		// info that we computed at the end of genssa.
  6814  		p := pp.Prog(obj.AFUNCDATA)
  6815  		p.From.SetConst(objabi.FUNCDATA_OpenCodedDeferInfo)
  6816  		p.To.Type = obj.TYPE_MEM
  6817  		p.To.Name = obj.NAME_EXTERN
  6818  		p.To.Sym = openDeferInfo
  6819  	}
  6820  
  6821  	emitWrappedFuncInfo(e, pp)
  6822  
  6823  	// Remember where each block starts.
  6824  	s.bstart = make([]*obj.Prog, f.NumBlocks())
  6825  	s.pp = pp
  6826  	var progToValue map[*obj.Prog]*ssa.Value
  6827  	var progToBlock map[*obj.Prog]*ssa.Block
  6828  	var valueToProgAfter []*obj.Prog // The first Prog following computation of a value v; v is visible at this point.
  6829  	gatherPrintInfo := f.PrintOrHtmlSSA || ssa.GenssaDump[f.Name]
  6830  	if gatherPrintInfo {
  6831  		progToValue = make(map[*obj.Prog]*ssa.Value, f.NumValues())
  6832  		progToBlock = make(map[*obj.Prog]*ssa.Block, f.NumBlocks())
  6833  		f.Logf("genssa %s\n", f.Name)
  6834  		progToBlock[s.pp.Next] = f.Blocks[0]
  6835  	}
  6836  
  6837  	if base.Ctxt.Flag_locationlists {
  6838  		if cap(f.Cache.ValueToProgAfter) < f.NumValues() {
  6839  			f.Cache.ValueToProgAfter = make([]*obj.Prog, f.NumValues())
  6840  		}
  6841  		valueToProgAfter = f.Cache.ValueToProgAfter[:f.NumValues()]
  6842  		for i := range valueToProgAfter {
  6843  			valueToProgAfter[i] = nil
  6844  		}
  6845  	}
  6846  
  6847  	// If the very first instruction is not tagged as a statement,
  6848  	// debuggers may attribute it to previous function in program.
  6849  	firstPos := src.NoXPos
  6850  	for _, v := range f.Entry.Values {
  6851  		if v.Pos.IsStmt() == src.PosIsStmt {
  6852  			firstPos = v.Pos
  6853  			v.Pos = firstPos.WithDefaultStmt()
  6854  			break
  6855  		}
  6856  	}
  6857  
  6858  	// inlMarks has an entry for each Prog that implements an inline mark.
  6859  	// It maps from that Prog to the global inlining id of the inlined body
  6860  	// which should unwind to this Prog's location.
  6861  	var inlMarks map[*obj.Prog]int32
  6862  	var inlMarkList []*obj.Prog
  6863  
  6864  	// inlMarksByPos maps from a (column 1) source position to the set of
  6865  	// Progs that are in the set above and have that source position.
  6866  	var inlMarksByPos map[src.XPos][]*obj.Prog
  6867  
  6868  	var argLiveIdx int = -1 // argument liveness info index
  6869  
  6870  	// Emit basic blocks
  6871  	for i, b := range f.Blocks {
  6872  		s.bstart[b.ID] = s.pp.Next
  6873  		s.lineRunStart = nil
  6874  		s.SetPos(s.pp.Pos.WithNotStmt()) // It needs a non-empty Pos, but cannot be a statement boundary (yet).
  6875  
  6876  		// Attach a "default" liveness info. Normally this will be
  6877  		// overwritten in the Values loop below for each Value. But
  6878  		// for an empty block this will be used for its control
  6879  		// instruction. We won't use the actual liveness map on a
  6880  		// control instruction. Just mark it something that is
  6881  		// preemptible, unless this function is "all unsafe".
  6882  		s.pp.NextLive = objw.LivenessIndex{StackMapIndex: -1, IsUnsafePoint: liveness.IsUnsafe(f)}
  6883  
  6884  		if idx, ok := argLiveBlockMap[b.ID]; ok && idx != argLiveIdx {
  6885  			argLiveIdx = idx
  6886  			p := s.pp.Prog(obj.APCDATA)
  6887  			p.From.SetConst(objabi.PCDATA_ArgLiveIndex)
  6888  			p.To.SetConst(int64(idx))
  6889  		}
  6890  
  6891  		// Emit values in block
  6892  		Arch.SSAMarkMoves(&s, b)
  6893  		for _, v := range b.Values {
  6894  			x := s.pp.Next
  6895  			s.DebugFriendlySetPosFrom(v)
  6896  
  6897  			if v.Op.ResultInArg0() && v.ResultReg() != v.Args[0].Reg() {
  6898  				v.Fatalf("input[0] and output not in same register %s", v.LongString())
  6899  			}
  6900  
  6901  			switch v.Op {
  6902  			case ssa.OpInitMem:
  6903  				// memory arg needs no code
  6904  			case ssa.OpArg:
  6905  				// input args need no code
  6906  			case ssa.OpSP, ssa.OpSB:
  6907  				// nothing to do
  6908  			case ssa.OpSelect0, ssa.OpSelect1, ssa.OpSelectN, ssa.OpMakeResult:
  6909  				// nothing to do
  6910  			case ssa.OpGetG:
  6911  				// nothing to do when there's a g register,
  6912  				// and checkLower complains if there's not
  6913  			case ssa.OpVarDef, ssa.OpVarLive, ssa.OpKeepAlive, ssa.OpVarKill:
  6914  				// nothing to do; already used by liveness
  6915  			case ssa.OpPhi:
  6916  				CheckLoweredPhi(v)
  6917  			case ssa.OpConvert:
  6918  				// nothing to do; no-op conversion for liveness
  6919  				if v.Args[0].Reg() != v.Reg() {
  6920  					v.Fatalf("OpConvert should be a no-op: %s; %s", v.Args[0].LongString(), v.LongString())
  6921  				}
  6922  			case ssa.OpInlMark:
  6923  				p := Arch.Ginsnop(s.pp)
  6924  				if inlMarks == nil {
  6925  					inlMarks = map[*obj.Prog]int32{}
  6926  					inlMarksByPos = map[src.XPos][]*obj.Prog{}
  6927  				}
  6928  				inlMarks[p] = v.AuxInt32()
  6929  				inlMarkList = append(inlMarkList, p)
  6930  				pos := v.Pos.AtColumn1()
  6931  				inlMarksByPos[pos] = append(inlMarksByPos[pos], p)
  6932  
  6933  			default:
  6934  				// Special case for first line in function; move it to the start (which cannot be a register-valued instruction)
  6935  				if firstPos != src.NoXPos && v.Op != ssa.OpArgIntReg && v.Op != ssa.OpArgFloatReg && v.Op != ssa.OpLoadReg && v.Op != ssa.OpStoreReg {
  6936  					s.SetPos(firstPos)
  6937  					firstPos = src.NoXPos
  6938  				}
  6939  				// Attach this safe point to the next
  6940  				// instruction.
  6941  				s.pp.NextLive = s.livenessMap.Get(v)
  6942  
  6943  				// let the backend handle it
  6944  				Arch.SSAGenValue(&s, v)
  6945  			}
  6946  
  6947  			if idx, ok := argLiveValueMap[v.ID]; ok && idx != argLiveIdx {
  6948  				argLiveIdx = idx
  6949  				p := s.pp.Prog(obj.APCDATA)
  6950  				p.From.SetConst(objabi.PCDATA_ArgLiveIndex)
  6951  				p.To.SetConst(int64(idx))
  6952  			}
  6953  
  6954  			if base.Ctxt.Flag_locationlists {
  6955  				valueToProgAfter[v.ID] = s.pp.Next
  6956  			}
  6957  
  6958  			if gatherPrintInfo {
  6959  				for ; x != s.pp.Next; x = x.Link {
  6960  					progToValue[x] = v
  6961  				}
  6962  			}
  6963  		}
  6964  		// If this is an empty infinite loop, stick a hardware NOP in there so that debuggers are less confused.
  6965  		if s.bstart[b.ID] == s.pp.Next && len(b.Succs) == 1 && b.Succs[0].Block() == b {
  6966  			p := Arch.Ginsnop(s.pp)
  6967  			p.Pos = p.Pos.WithIsStmt()
  6968  			if b.Pos == src.NoXPos {
  6969  				b.Pos = p.Pos // It needs a file, otherwise a no-file non-zero line causes confusion.  See #35652.
  6970  				if b.Pos == src.NoXPos {
  6971  					b.Pos = pp.Text.Pos // Sometimes p.Pos is empty.  See #35695.
  6972  				}
  6973  			}
  6974  			b.Pos = b.Pos.WithBogusLine() // Debuggers are not good about infinite loops, force a change in line number
  6975  		}
  6976  		// Emit control flow instructions for block
  6977  		var next *ssa.Block
  6978  		if i < len(f.Blocks)-1 && base.Flag.N == 0 {
  6979  			// If -N, leave next==nil so every block with successors
  6980  			// ends in a JMP (except call blocks - plive doesn't like
  6981  			// select{send,recv} followed by a JMP call).  Helps keep
  6982  			// line numbers for otherwise empty blocks.
  6983  			next = f.Blocks[i+1]
  6984  		}
  6985  		x := s.pp.Next
  6986  		s.SetPos(b.Pos)
  6987  		Arch.SSAGenBlock(&s, b, next)
  6988  		if gatherPrintInfo {
  6989  			for ; x != s.pp.Next; x = x.Link {
  6990  				progToBlock[x] = b
  6991  			}
  6992  		}
  6993  	}
  6994  	if f.Blocks[len(f.Blocks)-1].Kind == ssa.BlockExit {
  6995  		// We need the return address of a panic call to
  6996  		// still be inside the function in question. So if
  6997  		// it ends in a call which doesn't return, add a
  6998  		// nop (which will never execute) after the call.
  6999  		Arch.Ginsnop(pp)
  7000  	}
  7001  	if openDeferInfo != nil {
  7002  		// When doing open-coded defers, generate a disconnected call to
  7003  		// deferreturn and a return. This will be used to during panic
  7004  		// recovery to unwind the stack and return back to the runtime.
  7005  		s.pp.NextLive = s.livenessMap.DeferReturn
  7006  		p := pp.Prog(obj.ACALL)
  7007  		p.To.Type = obj.TYPE_MEM
  7008  		p.To.Name = obj.NAME_EXTERN
  7009  		p.To.Sym = ir.Syms.Deferreturn
  7010  
  7011  		// Load results into registers. So when a deferred function
  7012  		// recovers a panic, it will return to caller with right results.
  7013  		// The results are already in memory, because they are not SSA'd
  7014  		// when the function has defers (see canSSAName).
  7015  		for _, o := range f.OwnAux.ABIInfo().OutParams() {
  7016  			n := o.Name.(*ir.Name)
  7017  			rts, offs := o.RegisterTypesAndOffsets()
  7018  			for i := range o.Registers {
  7019  				Arch.LoadRegResult(&s, f, rts[i], ssa.ObjRegForAbiReg(o.Registers[i], f.Config), n, offs[i])
  7020  			}
  7021  		}
  7022  
  7023  		pp.Prog(obj.ARET)
  7024  	}
  7025  
  7026  	if inlMarks != nil {
  7027  		// We have some inline marks. Try to find other instructions we're
  7028  		// going to emit anyway, and use those instructions instead of the
  7029  		// inline marks.
  7030  		for p := pp.Text; p != nil; p = p.Link {
  7031  			if p.As == obj.ANOP || p.As == obj.AFUNCDATA || p.As == obj.APCDATA || p.As == obj.ATEXT || p.As == obj.APCALIGN || Arch.LinkArch.Family == sys.Wasm {
  7032  				// Don't use 0-sized instructions as inline marks, because we need
  7033  				// to identify inline mark instructions by pc offset.
  7034  				// (Some of these instructions are sometimes zero-sized, sometimes not.
  7035  				// We must not use anything that even might be zero-sized.)
  7036  				// TODO: are there others?
  7037  				continue
  7038  			}
  7039  			if _, ok := inlMarks[p]; ok {
  7040  				// Don't use inline marks themselves. We don't know
  7041  				// whether they will be zero-sized or not yet.
  7042  				continue
  7043  			}
  7044  			pos := p.Pos.AtColumn1()
  7045  			s := inlMarksByPos[pos]
  7046  			if len(s) == 0 {
  7047  				continue
  7048  			}
  7049  			for _, m := range s {
  7050  				// We found an instruction with the same source position as
  7051  				// some of the inline marks.
  7052  				// Use this instruction instead.
  7053  				p.Pos = p.Pos.WithIsStmt() // promote position to a statement
  7054  				pp.CurFunc.LSym.Func().AddInlMark(p, inlMarks[m])
  7055  				// Make the inline mark a real nop, so it doesn't generate any code.
  7056  				m.As = obj.ANOP
  7057  				m.Pos = src.NoXPos
  7058  				m.From = obj.Addr{}
  7059  				m.To = obj.Addr{}
  7060  			}
  7061  			delete(inlMarksByPos, pos)
  7062  		}
  7063  		// Any unmatched inline marks now need to be added to the inlining tree (and will generate a nop instruction).
  7064  		for _, p := range inlMarkList {
  7065  			if p.As != obj.ANOP {
  7066  				pp.CurFunc.LSym.Func().AddInlMark(p, inlMarks[p])
  7067  			}
  7068  		}
  7069  	}
  7070  
  7071  	if base.Ctxt.Flag_locationlists {
  7072  		var debugInfo *ssa.FuncDebug
  7073  		debugInfo = e.curfn.DebugInfo.(*ssa.FuncDebug)
  7074  		if e.curfn.ABI == obj.ABIInternal && base.Flag.N != 0 {
  7075  			ssa.BuildFuncDebugNoOptimized(base.Ctxt, f, base.Debug.LocationLists > 1, StackOffset, debugInfo)
  7076  		} else {
  7077  			ssa.BuildFuncDebug(base.Ctxt, f, base.Debug.LocationLists > 1, StackOffset, debugInfo)
  7078  		}
  7079  		bstart := s.bstart
  7080  		idToIdx := make([]int, f.NumBlocks())
  7081  		for i, b := range f.Blocks {
  7082  			idToIdx[b.ID] = i
  7083  		}
  7084  		// Note that at this moment, Prog.Pc is a sequence number; it's
  7085  		// not a real PC until after assembly, so this mapping has to
  7086  		// be done later.
  7087  		debugInfo.GetPC = func(b, v ssa.ID) int64 {
  7088  			switch v {
  7089  			case ssa.BlockStart.ID:
  7090  				if b == f.Entry.ID {
  7091  					return 0 // Start at the very beginning, at the assembler-generated prologue.
  7092  					// this should only happen for function args (ssa.OpArg)
  7093  				}
  7094  				return bstart[b].Pc
  7095  			case ssa.BlockEnd.ID:
  7096  				blk := f.Blocks[idToIdx[b]]
  7097  				nv := len(blk.Values)
  7098  				return valueToProgAfter[blk.Values[nv-1].ID].Pc
  7099  			case ssa.FuncEnd.ID:
  7100  				return e.curfn.LSym.Size
  7101  			default:
  7102  				return valueToProgAfter[v].Pc
  7103  			}
  7104  		}
  7105  	}
  7106  
  7107  	// Resolve branches, and relax DefaultStmt into NotStmt
  7108  	for _, br := range s.Branches {
  7109  		br.P.To.SetTarget(s.bstart[br.B.ID])
  7110  		if br.P.Pos.IsStmt() != src.PosIsStmt {
  7111  			br.P.Pos = br.P.Pos.WithNotStmt()
  7112  		} else if v0 := br.B.FirstPossibleStmtValue(); v0 != nil && v0.Pos.Line() == br.P.Pos.Line() && v0.Pos.IsStmt() == src.PosIsStmt {
  7113  			br.P.Pos = br.P.Pos.WithNotStmt()
  7114  		}
  7115  
  7116  	}
  7117  
  7118  	if e.log { // spew to stdout
  7119  		filename := ""
  7120  		for p := pp.Text; p != nil; p = p.Link {
  7121  			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
  7122  				filename = p.InnermostFilename()
  7123  				f.Logf("# %s\n", filename)
  7124  			}
  7125  
  7126  			var s string
  7127  			if v, ok := progToValue[p]; ok {
  7128  				s = v.String()
  7129  			} else if b, ok := progToBlock[p]; ok {
  7130  				s = b.String()
  7131  			} else {
  7132  				s = "   " // most value and branch strings are 2-3 characters long
  7133  			}
  7134  			f.Logf(" %-6s\t%.5d (%s)\t%s\n", s, p.Pc, p.InnermostLineNumber(), p.InstructionString())
  7135  		}
  7136  	}
  7137  	if f.HTMLWriter != nil { // spew to ssa.html
  7138  		var buf bytes.Buffer
  7139  		buf.WriteString("<code>")
  7140  		buf.WriteString("<dl class=\"ssa-gen\">")
  7141  		filename := ""
  7142  		for p := pp.Text; p != nil; p = p.Link {
  7143  			// Don't spam every line with the file name, which is often huge.
  7144  			// Only print changes, and "unknown" is not a change.
  7145  			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
  7146  				filename = p.InnermostFilename()
  7147  				buf.WriteString("<dt class=\"ssa-prog-src\"></dt><dd class=\"ssa-prog\">")
  7148  				buf.WriteString(html.EscapeString("# " + filename))
  7149  				buf.WriteString("</dd>")
  7150  			}
  7151  
  7152  			buf.WriteString("<dt class=\"ssa-prog-src\">")
  7153  			if v, ok := progToValue[p]; ok {
  7154  				buf.WriteString(v.HTML())
  7155  			} else if b, ok := progToBlock[p]; ok {
  7156  				buf.WriteString("<b>" + b.HTML() + "</b>")
  7157  			}
  7158  			buf.WriteString("</dt>")
  7159  			buf.WriteString("<dd class=\"ssa-prog\">")
  7160  			buf.WriteString(fmt.Sprintf("%.5d <span class=\"l%v line-number\">(%s)</span> %s", p.Pc, p.InnermostLineNumber(), p.InnermostLineNumberHTML(), html.EscapeString(p.InstructionString())))
  7161  			buf.WriteString("</dd>")
  7162  		}
  7163  		buf.WriteString("</dl>")
  7164  		buf.WriteString("</code>")
  7165  		f.HTMLWriter.WriteColumn("genssa", "genssa", "ssa-prog", buf.String())
  7166  	}
  7167  	if ssa.GenssaDump[f.Name] {
  7168  		fi := f.DumpFileForPhase("genssa")
  7169  		if fi != nil {
  7170  
  7171  			// inliningDiffers if any filename changes or if any line number except the innermost (index 0) changes.
  7172  			inliningDiffers := func(a, b []src.Pos) bool {
  7173  				if len(a) != len(b) {
  7174  					return true
  7175  				}
  7176  				for i := range a {
  7177  					if a[i].Filename() != b[i].Filename() {
  7178  						return true
  7179  					}
  7180  					if i > 0 && a[i].Line() != b[i].Line() {
  7181  						return true
  7182  					}
  7183  				}
  7184  				return false
  7185  			}
  7186  
  7187  			var allPosOld []src.Pos
  7188  			var allPos []src.Pos
  7189  
  7190  			for p := pp.Text; p != nil; p = p.Link {
  7191  				if p.Pos.IsKnown() {
  7192  					allPos = p.AllPos(allPos)
  7193  					if inliningDiffers(allPos, allPosOld) {
  7194  						for i := len(allPos) - 1; i >= 0; i-- {
  7195  							pos := allPos[i]
  7196  							fmt.Fprintf(fi, "# %s:%d\n", pos.Filename(), pos.Line())
  7197  						}
  7198  						allPos, allPosOld = allPosOld, allPos // swap, not copy, so that they do not share slice storage.
  7199  					}
  7200  				}
  7201  
  7202  				var s string
  7203  				if v, ok := progToValue[p]; ok {
  7204  					s = v.String()
  7205  				} else if b, ok := progToBlock[p]; ok {
  7206  					s = b.String()
  7207  				} else {
  7208  					s = "   " // most value and branch strings are 2-3 characters long
  7209  				}
  7210  				fmt.Fprintf(fi, " %-6s\t%.5d %s\t%s\n", s, p.Pc, ssa.StmtString(p.Pos), p.InstructionString())
  7211  			}
  7212  			fi.Close()
  7213  		}
  7214  	}
  7215  
  7216  	defframe(&s, e, f)
  7217  
  7218  	f.HTMLWriter.Close()
  7219  	f.HTMLWriter = nil
  7220  }
  7221  
  7222  func defframe(s *State, e *ssafn, f *ssa.Func) {
  7223  	pp := s.pp
  7224  
  7225  	frame := types.Rnd(s.maxarg+e.stksize, int64(types.RegSize))
  7226  	if Arch.PadFrame != nil {
  7227  		frame = Arch.PadFrame(frame)
  7228  	}
  7229  
  7230  	// Fill in argument and frame size.
  7231  	pp.Text.To.Type = obj.TYPE_TEXTSIZE
  7232  	pp.Text.To.Val = int32(types.Rnd(f.OwnAux.ArgWidth(), int64(types.RegSize)))
  7233  	pp.Text.To.Offset = frame
  7234  
  7235  	p := pp.Text
  7236  
  7237  	// Insert code to spill argument registers if the named slot may be partially
  7238  	// live. That is, the named slot is considered live by liveness analysis,
  7239  	// (because a part of it is live), but we may not spill all parts into the
  7240  	// slot. This can only happen with aggregate-typed arguments that are SSA-able
  7241  	// and not address-taken (for non-SSA-able or address-taken arguments we always
  7242  	// spill upfront).
  7243  	// Note: spilling is unnecessary in the -N/no-optimize case, since all values
  7244  	// will be considered non-SSAable and spilled up front.
  7245  	// TODO(register args) Make liveness more fine-grained to that partial spilling is okay.
  7246  	if f.OwnAux.ABIInfo().InRegistersUsed() != 0 && base.Flag.N == 0 {
  7247  		// First, see if it is already spilled before it may be live. Look for a spill
  7248  		// in the entry block up to the first safepoint.
  7249  		type nameOff struct {
  7250  			n   *ir.Name
  7251  			off int64
  7252  		}
  7253  		partLiveArgsSpilled := make(map[nameOff]bool)
  7254  		for _, v := range f.Entry.Values {
  7255  			if v.Op.IsCall() {
  7256  				break
  7257  			}
  7258  			if v.Op != ssa.OpStoreReg || v.Args[0].Op != ssa.OpArgIntReg {
  7259  				continue
  7260  			}
  7261  			n, off := ssa.AutoVar(v)
  7262  			if n.Class != ir.PPARAM || n.Addrtaken() || !TypeOK(n.Type()) || !s.partLiveArgs[n] {
  7263  				continue
  7264  			}
  7265  			partLiveArgsSpilled[nameOff{n, off}] = true
  7266  		}
  7267  
  7268  		// Then, insert code to spill registers if not already.
  7269  		for _, a := range f.OwnAux.ABIInfo().InParams() {
  7270  			n, ok := a.Name.(*ir.Name)
  7271  			if !ok || n.Addrtaken() || !TypeOK(n.Type()) || !s.partLiveArgs[n] || len(a.Registers) <= 1 {
  7272  				continue
  7273  			}
  7274  			rts, offs := a.RegisterTypesAndOffsets()
  7275  			for i := range a.Registers {
  7276  				if !rts[i].HasPointers() {
  7277  					continue
  7278  				}
  7279  				if partLiveArgsSpilled[nameOff{n, offs[i]}] {
  7280  					continue // already spilled
  7281  				}
  7282  				reg := ssa.ObjRegForAbiReg(a.Registers[i], f.Config)
  7283  				p = Arch.SpillArgReg(pp, p, f, rts[i], reg, n, offs[i])
  7284  			}
  7285  		}
  7286  	}
  7287  
  7288  	// Insert code to zero ambiguously live variables so that the
  7289  	// garbage collector only sees initialized values when it
  7290  	// looks for pointers.
  7291  	var lo, hi int64
  7292  
  7293  	// Opaque state for backend to use. Current backends use it to
  7294  	// keep track of which helper registers have been zeroed.
  7295  	var state uint32
  7296  
  7297  	// Iterate through declarations. Autos are sorted in decreasing
  7298  	// frame offset order.
  7299  	for _, n := range e.curfn.Dcl {
  7300  		if !n.Needzero() {
  7301  			continue
  7302  		}
  7303  		if n.Class != ir.PAUTO {
  7304  			e.Fatalf(n.Pos(), "needzero class %d", n.Class)
  7305  		}
  7306  		if n.Type().Size()%int64(types.PtrSize) != 0 || n.FrameOffset()%int64(types.PtrSize) != 0 || n.Type().Size() == 0 {
  7307  			e.Fatalf(n.Pos(), "var %L has size %d offset %d", n, n.Type().Size(), n.Offset_)
  7308  		}
  7309  
  7310  		if lo != hi && n.FrameOffset()+n.Type().Size() >= lo-int64(2*types.RegSize) {
  7311  			// Merge with range we already have.
  7312  			lo = n.FrameOffset()
  7313  			continue
  7314  		}
  7315  
  7316  		// Zero old range
  7317  		p = Arch.ZeroRange(pp, p, frame+lo, hi-lo, &state)
  7318  
  7319  		// Set new range.
  7320  		lo = n.FrameOffset()
  7321  		hi = lo + n.Type().Size()
  7322  	}
  7323  
  7324  	// Zero final range.
  7325  	Arch.ZeroRange(pp, p, frame+lo, hi-lo, &state)
  7326  }
  7327  
  7328  // For generating consecutive jump instructions to model a specific branching
  7329  type IndexJump struct {
  7330  	Jump  obj.As
  7331  	Index int
  7332  }
  7333  
  7334  func (s *State) oneJump(b *ssa.Block, jump *IndexJump) {
  7335  	p := s.Br(jump.Jump, b.Succs[jump.Index].Block())
  7336  	p.Pos = b.Pos
  7337  }
  7338  
  7339  // CombJump generates combinational instructions (2 at present) for a block jump,
  7340  // thereby the behaviour of non-standard condition codes could be simulated
  7341  func (s *State) CombJump(b, next *ssa.Block, jumps *[2][2]IndexJump) {
  7342  	switch next {
  7343  	case b.Succs[0].Block():
  7344  		s.oneJump(b, &jumps[0][0])
  7345  		s.oneJump(b, &jumps[0][1])
  7346  	case b.Succs[1].Block():
  7347  		s.oneJump(b, &jumps[1][0])
  7348  		s.oneJump(b, &jumps[1][1])
  7349  	default:
  7350  		var q *obj.Prog
  7351  		if b.Likely != ssa.BranchUnlikely {
  7352  			s.oneJump(b, &jumps[1][0])
  7353  			s.oneJump(b, &jumps[1][1])
  7354  			q = s.Br(obj.AJMP, b.Succs[1].Block())
  7355  		} else {
  7356  			s.oneJump(b, &jumps[0][0])
  7357  			s.oneJump(b, &jumps[0][1])
  7358  			q = s.Br(obj.AJMP, b.Succs[0].Block())
  7359  		}
  7360  		q.Pos = b.Pos
  7361  	}
  7362  }
  7363  
  7364  // AddAux adds the offset in the aux fields (AuxInt and Aux) of v to a.
  7365  func AddAux(a *obj.Addr, v *ssa.Value) {
  7366  	AddAux2(a, v, v.AuxInt)
  7367  }
  7368  func AddAux2(a *obj.Addr, v *ssa.Value, offset int64) {
  7369  	if a.Type != obj.TYPE_MEM && a.Type != obj.TYPE_ADDR {
  7370  		v.Fatalf("bad AddAux addr %v", a)
  7371  	}
  7372  	// add integer offset
  7373  	a.Offset += offset
  7374  
  7375  	// If no additional symbol offset, we're done.
  7376  	if v.Aux == nil {
  7377  		return
  7378  	}
  7379  	// Add symbol's offset from its base register.
  7380  	switch n := v.Aux.(type) {
  7381  	case *ssa.AuxCall:
  7382  		a.Name = obj.NAME_EXTERN
  7383  		a.Sym = n.Fn
  7384  	case *obj.LSym:
  7385  		a.Name = obj.NAME_EXTERN
  7386  		a.Sym = n
  7387  	case *ir.Name:
  7388  		if n.Class == ir.PPARAM || (n.Class == ir.PPARAMOUT && !n.IsOutputParamInRegisters()) {
  7389  			a.Name = obj.NAME_PARAM
  7390  			a.Sym = ir.Orig(n).(*ir.Name).Linksym()
  7391  			a.Offset += n.FrameOffset()
  7392  			break
  7393  		}
  7394  		a.Name = obj.NAME_AUTO
  7395  		if n.Class == ir.PPARAMOUT {
  7396  			a.Sym = ir.Orig(n).(*ir.Name).Linksym()
  7397  		} else {
  7398  			a.Sym = n.Linksym()
  7399  		}
  7400  		a.Offset += n.FrameOffset()
  7401  	default:
  7402  		v.Fatalf("aux in %s not implemented %#v", v, v.Aux)
  7403  	}
  7404  }
  7405  
  7406  // extendIndex extends v to a full int width.
  7407  // panic with the given kind if v does not fit in an int (only on 32-bit archs).
  7408  func (s *state) extendIndex(idx, len *ssa.Value, kind ssa.BoundsKind, bounded bool) *ssa.Value {
  7409  	size := idx.Type.Size()
  7410  	if size == s.config.PtrSize {
  7411  		return idx
  7412  	}
  7413  	if size > s.config.PtrSize {
  7414  		// truncate 64-bit indexes on 32-bit pointer archs. Test the
  7415  		// high word and branch to out-of-bounds failure if it is not 0.
  7416  		var lo *ssa.Value
  7417  		if idx.Type.IsSigned() {
  7418  			lo = s.newValue1(ssa.OpInt64Lo, types.Types[types.TINT], idx)
  7419  		} else {
  7420  			lo = s.newValue1(ssa.OpInt64Lo, types.Types[types.TUINT], idx)
  7421  		}
  7422  		if bounded || base.Flag.B != 0 {
  7423  			return lo
  7424  		}
  7425  		bNext := s.f.NewBlock(ssa.BlockPlain)
  7426  		bPanic := s.f.NewBlock(ssa.BlockExit)
  7427  		hi := s.newValue1(ssa.OpInt64Hi, types.Types[types.TUINT32], idx)
  7428  		cmp := s.newValue2(ssa.OpEq32, types.Types[types.TBOOL], hi, s.constInt32(types.Types[types.TUINT32], 0))
  7429  		if !idx.Type.IsSigned() {
  7430  			switch kind {
  7431  			case ssa.BoundsIndex:
  7432  				kind = ssa.BoundsIndexU
  7433  			case ssa.BoundsSliceAlen:
  7434  				kind = ssa.BoundsSliceAlenU
  7435  			case ssa.BoundsSliceAcap:
  7436  				kind = ssa.BoundsSliceAcapU
  7437  			case ssa.BoundsSliceB:
  7438  				kind = ssa.BoundsSliceBU
  7439  			case ssa.BoundsSlice3Alen:
  7440  				kind = ssa.BoundsSlice3AlenU
  7441  			case ssa.BoundsSlice3Acap:
  7442  				kind = ssa.BoundsSlice3AcapU
  7443  			case ssa.BoundsSlice3B:
  7444  				kind = ssa.BoundsSlice3BU
  7445  			case ssa.BoundsSlice3C:
  7446  				kind = ssa.BoundsSlice3CU
  7447  			}
  7448  		}
  7449  		b := s.endBlock()
  7450  		b.Kind = ssa.BlockIf
  7451  		b.SetControl(cmp)
  7452  		b.Likely = ssa.BranchLikely
  7453  		b.AddEdgeTo(bNext)
  7454  		b.AddEdgeTo(bPanic)
  7455  
  7456  		s.startBlock(bPanic)
  7457  		mem := s.newValue4I(ssa.OpPanicExtend, types.TypeMem, int64(kind), hi, lo, len, s.mem())
  7458  		s.endBlock().SetControl(mem)
  7459  		s.startBlock(bNext)
  7460  
  7461  		return lo
  7462  	}
  7463  
  7464  	// Extend value to the required size
  7465  	var op ssa.Op
  7466  	if idx.Type.IsSigned() {
  7467  		switch 10*size + s.config.PtrSize {
  7468  		case 14:
  7469  			op = ssa.OpSignExt8to32
  7470  		case 18:
  7471  			op = ssa.OpSignExt8to64
  7472  		case 24:
  7473  			op = ssa.OpSignExt16to32
  7474  		case 28:
  7475  			op = ssa.OpSignExt16to64
  7476  		case 48:
  7477  			op = ssa.OpSignExt32to64
  7478  		default:
  7479  			s.Fatalf("bad signed index extension %s", idx.Type)
  7480  		}
  7481  	} else {
  7482  		switch 10*size + s.config.PtrSize {
  7483  		case 14:
  7484  			op = ssa.OpZeroExt8to32
  7485  		case 18:
  7486  			op = ssa.OpZeroExt8to64
  7487  		case 24:
  7488  			op = ssa.OpZeroExt16to32
  7489  		case 28:
  7490  			op = ssa.OpZeroExt16to64
  7491  		case 48:
  7492  			op = ssa.OpZeroExt32to64
  7493  		default:
  7494  			s.Fatalf("bad unsigned index extension %s", idx.Type)
  7495  		}
  7496  	}
  7497  	return s.newValue1(op, types.Types[types.TINT], idx)
  7498  }
  7499  
  7500  // CheckLoweredPhi checks that regalloc and stackalloc correctly handled phi values.
  7501  // Called during ssaGenValue.
  7502  func CheckLoweredPhi(v *ssa.Value) {
  7503  	if v.Op != ssa.OpPhi {
  7504  		v.Fatalf("CheckLoweredPhi called with non-phi value: %v", v.LongString())
  7505  	}
  7506  	if v.Type.IsMemory() {
  7507  		return
  7508  	}
  7509  	f := v.Block.Func
  7510  	loc := f.RegAlloc[v.ID]
  7511  	for _, a := range v.Args {
  7512  		if aloc := f.RegAlloc[a.ID]; aloc != loc { // TODO: .Equal() instead?
  7513  			v.Fatalf("phi arg at different location than phi: %v @ %s, but arg %v @ %s\n%s\n", v, loc, a, aloc, v.Block.Func)
  7514  		}
  7515  	}
  7516  }
  7517  
  7518  // CheckLoweredGetClosurePtr checks that v is the first instruction in the function's entry block,
  7519  // except for incoming in-register arguments.
  7520  // The output of LoweredGetClosurePtr is generally hardwired to the correct register.
  7521  // That register contains the closure pointer on closure entry.
  7522  func CheckLoweredGetClosurePtr(v *ssa.Value) {
  7523  	entry := v.Block.Func.Entry
  7524  	if entry != v.Block {
  7525  		base.Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
  7526  	}
  7527  	for _, w := range entry.Values {
  7528  		if w == v {
  7529  			break
  7530  		}
  7531  		switch w.Op {
  7532  		case ssa.OpArgIntReg, ssa.OpArgFloatReg:
  7533  			// okay
  7534  		default:
  7535  			base.Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
  7536  		}
  7537  	}
  7538  }
  7539  
  7540  // CheckArgReg ensures that v is in the function's entry block.
  7541  func CheckArgReg(v *ssa.Value) {
  7542  	entry := v.Block.Func.Entry
  7543  	if entry != v.Block {
  7544  		base.Fatalf("in %s, badly placed ArgIReg or ArgFReg: %v %v", v.Block.Func.Name, v.Block, v)
  7545  	}
  7546  }
  7547  
  7548  func AddrAuto(a *obj.Addr, v *ssa.Value) {
  7549  	n, off := ssa.AutoVar(v)
  7550  	a.Type = obj.TYPE_MEM
  7551  	a.Sym = n.Linksym()
  7552  	a.Reg = int16(Arch.REGSP)
  7553  	a.Offset = n.FrameOffset() + off
  7554  	if n.Class == ir.PPARAM || (n.Class == ir.PPARAMOUT && !n.IsOutputParamInRegisters()) {
  7555  		a.Name = obj.NAME_PARAM
  7556  	} else {
  7557  		a.Name = obj.NAME_AUTO
  7558  	}
  7559  }
  7560  
  7561  // Call returns a new CALL instruction for the SSA value v.
  7562  // It uses PrepareCall to prepare the call.
  7563  func (s *State) Call(v *ssa.Value) *obj.Prog {
  7564  	pPosIsStmt := s.pp.Pos.IsStmt() // The statement-ness fo the call comes from ssaGenState
  7565  	s.PrepareCall(v)
  7566  
  7567  	p := s.Prog(obj.ACALL)
  7568  	if pPosIsStmt == src.PosIsStmt {
  7569  		p.Pos = v.Pos.WithIsStmt()
  7570  	} else {
  7571  		p.Pos = v.Pos.WithNotStmt()
  7572  	}
  7573  	if sym, ok := v.Aux.(*ssa.AuxCall); ok && sym.Fn != nil {
  7574  		p.To.Type = obj.TYPE_MEM
  7575  		p.To.Name = obj.NAME_EXTERN
  7576  		p.To.Sym = sym.Fn
  7577  	} else {
  7578  		// TODO(mdempsky): Can these differences be eliminated?
  7579  		switch Arch.LinkArch.Family {
  7580  		case sys.AMD64, sys.I386, sys.PPC64, sys.RISCV64, sys.S390X, sys.Wasm:
  7581  			p.To.Type = obj.TYPE_REG
  7582  		case sys.ARM, sys.ARM64, sys.MIPS, sys.MIPS64:
  7583  			p.To.Type = obj.TYPE_MEM
  7584  		default:
  7585  			base.Fatalf("unknown indirect call family")
  7586  		}
  7587  		p.To.Reg = v.Args[0].Reg()
  7588  	}
  7589  	return p
  7590  }
  7591  
  7592  // TailCall returns a new tail call instruction for the SSA value v.
  7593  // It is like Call, but for a tail call.
  7594  func (s *State) TailCall(v *ssa.Value) *obj.Prog {
  7595  	p := s.Call(v)
  7596  	p.As = obj.ARET
  7597  	return p
  7598  }
  7599  
  7600  // PrepareCall prepares to emit a CALL instruction for v and does call-related bookkeeping.
  7601  // It must be called immediately before emitting the actual CALL instruction,
  7602  // since it emits PCDATA for the stack map at the call (calls are safe points).
  7603  func (s *State) PrepareCall(v *ssa.Value) {
  7604  	idx := s.livenessMap.Get(v)
  7605  	if !idx.StackMapValid() {
  7606  		// See Liveness.hasStackMap.
  7607  		if sym, ok := v.Aux.(*ssa.AuxCall); !ok || !(sym.Fn == ir.Syms.Typedmemclr || sym.Fn == ir.Syms.Typedmemmove) {
  7608  			base.Fatalf("missing stack map index for %v", v.LongString())
  7609  		}
  7610  	}
  7611  
  7612  	call, ok := v.Aux.(*ssa.AuxCall)
  7613  
  7614  	if ok {
  7615  		// Record call graph information for nowritebarrierrec
  7616  		// analysis.
  7617  		if nowritebarrierrecCheck != nil {
  7618  			nowritebarrierrecCheck.recordCall(s.pp.CurFunc, call.Fn, v.Pos)
  7619  		}
  7620  	}
  7621  
  7622  	if s.maxarg < v.AuxInt {
  7623  		s.maxarg = v.AuxInt
  7624  	}
  7625  }
  7626  
  7627  // UseArgs records the fact that an instruction needs a certain amount of
  7628  // callee args space for its use.
  7629  func (s *State) UseArgs(n int64) {
  7630  	if s.maxarg < n {
  7631  		s.maxarg = n
  7632  	}
  7633  }
  7634  
  7635  // fieldIdx finds the index of the field referred to by the ODOT node n.
  7636  func fieldIdx(n *ir.SelectorExpr) int {
  7637  	t := n.X.Type()
  7638  	if !t.IsStruct() {
  7639  		panic("ODOT's LHS is not a struct")
  7640  	}
  7641  
  7642  	for i, f := range t.Fields().Slice() {
  7643  		if f.Sym == n.Sel {
  7644  			if f.Offset != n.Offset() {
  7645  				panic("field offset doesn't match")
  7646  			}
  7647  			return i
  7648  		}
  7649  	}
  7650  	panic(fmt.Sprintf("can't find field in expr %v\n", n))
  7651  
  7652  	// TODO: keep the result of this function somewhere in the ODOT Node
  7653  	// so we don't have to recompute it each time we need it.
  7654  }
  7655  
  7656  // ssafn holds frontend information about a function that the backend is processing.
  7657  // It also exports a bunch of compiler services for the ssa backend.
  7658  type ssafn struct {
  7659  	curfn      *ir.Func
  7660  	strings    map[string]*obj.LSym // map from constant string to data symbols
  7661  	stksize    int64                // stack size for current frame
  7662  	stkptrsize int64                // prefix of stack containing pointers
  7663  	log        bool                 // print ssa debug to the stdout
  7664  }
  7665  
  7666  // StringData returns a symbol which
  7667  // is the data component of a global string constant containing s.
  7668  func (e *ssafn) StringData(s string) *obj.LSym {
  7669  	if aux, ok := e.strings[s]; ok {
  7670  		return aux
  7671  	}
  7672  	if e.strings == nil {
  7673  		e.strings = make(map[string]*obj.LSym)
  7674  	}
  7675  	data := staticdata.StringSym(e.curfn.Pos(), s)
  7676  	e.strings[s] = data
  7677  	return data
  7678  }
  7679  
  7680  func (e *ssafn) Auto(pos src.XPos, t *types.Type) *ir.Name {
  7681  	return typecheck.TempAt(pos, e.curfn, t) // Note: adds new auto to e.curfn.Func.Dcl list
  7682  }
  7683  
  7684  // SplitSlot returns a slot representing the data of parent starting at offset.
  7685  func (e *ssafn) SplitSlot(parent *ssa.LocalSlot, suffix string, offset int64, t *types.Type) ssa.LocalSlot {
  7686  	node := parent.N
  7687  
  7688  	if node.Class != ir.PAUTO || node.Addrtaken() {
  7689  		// addressed things and non-autos retain their parents (i.e., cannot truly be split)
  7690  		return ssa.LocalSlot{N: node, Type: t, Off: parent.Off + offset}
  7691  	}
  7692  
  7693  	s := &types.Sym{Name: node.Sym().Name + suffix, Pkg: types.LocalPkg}
  7694  	n := ir.NewNameAt(parent.N.Pos(), s)
  7695  	s.Def = n
  7696  	ir.AsNode(s.Def).Name().SetUsed(true)
  7697  	n.SetType(t)
  7698  	n.Class = ir.PAUTO
  7699  	n.SetEsc(ir.EscNever)
  7700  	n.Curfn = e.curfn
  7701  	e.curfn.Dcl = append(e.curfn.Dcl, n)
  7702  	types.CalcSize(t)
  7703  	return ssa.LocalSlot{N: n, Type: t, Off: 0, SplitOf: parent, SplitOffset: offset}
  7704  }
  7705  
  7706  func (e *ssafn) CanSSA(t *types.Type) bool {
  7707  	return TypeOK(t)
  7708  }
  7709  
  7710  func (e *ssafn) Line(pos src.XPos) string {
  7711  	return base.FmtPos(pos)
  7712  }
  7713  
  7714  // Log logs a message from the compiler.
  7715  func (e *ssafn) Logf(msg string, args ...interface{}) {
  7716  	if e.log {
  7717  		fmt.Printf(msg, args...)
  7718  	}
  7719  }
  7720  
  7721  func (e *ssafn) Log() bool {
  7722  	return e.log
  7723  }
  7724  
  7725  // Fatal reports a compiler error and exits.
  7726  func (e *ssafn) Fatalf(pos src.XPos, msg string, args ...interface{}) {
  7727  	base.Pos = pos
  7728  	nargs := append([]interface{}{ir.FuncName(e.curfn)}, args...)
  7729  	base.Fatalf("'%s': "+msg, nargs...)
  7730  }
  7731  
  7732  // Warnl reports a "warning", which is usually flag-triggered
  7733  // logging output for the benefit of tests.
  7734  func (e *ssafn) Warnl(pos src.XPos, fmt_ string, args ...interface{}) {
  7735  	base.WarnfAt(pos, fmt_, args...)
  7736  }
  7737  
  7738  func (e *ssafn) Debug_checknil() bool {
  7739  	return base.Debug.Nil != 0
  7740  }
  7741  
  7742  func (e *ssafn) UseWriteBarrier() bool {
  7743  	return base.Flag.WB
  7744  }
  7745  
  7746  func (e *ssafn) Syslook(name string) *obj.LSym {
  7747  	switch name {
  7748  	case "goschedguarded":
  7749  		return ir.Syms.Goschedguarded
  7750  	case "writeBarrier":
  7751  		return ir.Syms.WriteBarrier
  7752  	case "gcWriteBarrier":
  7753  		return ir.Syms.GCWriteBarrier
  7754  	case "typedmemmove":
  7755  		return ir.Syms.Typedmemmove
  7756  	case "typedmemclr":
  7757  		return ir.Syms.Typedmemclr
  7758  	}
  7759  	e.Fatalf(src.NoXPos, "unknown Syslook func %v", name)
  7760  	return nil
  7761  }
  7762  
  7763  func (e *ssafn) SetWBPos(pos src.XPos) {
  7764  	e.curfn.SetWBPos(pos)
  7765  }
  7766  
  7767  func (e *ssafn) MyImportPath() string {
  7768  	return base.Ctxt.Pkgpath
  7769  }
  7770  
  7771  func clobberBase(n ir.Node) ir.Node {
  7772  	if n.Op() == ir.ODOT {
  7773  		n := n.(*ir.SelectorExpr)
  7774  		if n.X.Type().NumFields() == 1 {
  7775  			return clobberBase(n.X)
  7776  		}
  7777  	}
  7778  	if n.Op() == ir.OINDEX {
  7779  		n := n.(*ir.IndexExpr)
  7780  		if n.X.Type().IsArray() && n.X.Type().NumElem() == 1 {
  7781  			return clobberBase(n.X)
  7782  		}
  7783  	}
  7784  	return n
  7785  }
  7786  
  7787  // callTargetLSym returns the correct LSym to call 'callee' using its ABI.
  7788  func callTargetLSym(callee *ir.Name) *obj.LSym {
  7789  	if callee.Func == nil {
  7790  		// TODO(austin): This happens in a few cases of
  7791  		// compiler-generated functions. These are all
  7792  		// ABIInternal. It would be better if callee.Func was
  7793  		// never nil and we didn't need this case.
  7794  		return callee.Linksym()
  7795  	}
  7796  
  7797  	return callee.LinksymABI(callee.Func.ABI)
  7798  }
  7799  
  7800  func min8(a, b int8) int8 {
  7801  	if a < b {
  7802  		return a
  7803  	}
  7804  	return b
  7805  }
  7806  
  7807  func max8(a, b int8) int8 {
  7808  	if a > b {
  7809  		return a
  7810  	}
  7811  	return b
  7812  }
  7813  
  7814  // deferstruct makes a runtime._defer structure.
  7815  func deferstruct() *types.Type {
  7816  	makefield := func(name string, typ *types.Type) *types.Field {
  7817  		// Unlike the global makefield function, this one needs to set Pkg
  7818  		// because these types might be compared (in SSA CSE sorting).
  7819  		// TODO: unify this makefield and the global one above.
  7820  		sym := &types.Sym{Name: name, Pkg: types.LocalPkg}
  7821  		return types.NewField(src.NoXPos, sym, typ)
  7822  	}
  7823  	// These fields must match the ones in runtime/runtime2.go:_defer and
  7824  	// (*state).call above.
  7825  	fields := []*types.Field{
  7826  		makefield("started", types.Types[types.TBOOL]),
  7827  		makefield("heap", types.Types[types.TBOOL]),
  7828  		makefield("openDefer", types.Types[types.TBOOL]),
  7829  		makefield("sp", types.Types[types.TUINTPTR]),
  7830  		makefield("pc", types.Types[types.TUINTPTR]),
  7831  		// Note: the types here don't really matter. Defer structures
  7832  		// are always scanned explicitly during stack copying and GC,
  7833  		// so we make them uintptr type even though they are real pointers.
  7834  		makefield("fn", types.Types[types.TUINTPTR]),
  7835  		makefield("_panic", types.Types[types.TUINTPTR]),
  7836  		makefield("link", types.Types[types.TUINTPTR]),
  7837  		makefield("fd", types.Types[types.TUINTPTR]),
  7838  		makefield("varp", types.Types[types.TUINTPTR]),
  7839  		makefield("framepc", types.Types[types.TUINTPTR]),
  7840  	}
  7841  
  7842  	// build struct holding the above fields
  7843  	s := types.NewStruct(types.NoPkg, fields)
  7844  	s.SetNoalg(true)
  7845  	types.CalcStructSize(s)
  7846  	return s
  7847  }
  7848  
  7849  // SlotAddr uses LocalSlot information to initialize an obj.Addr
  7850  // The resulting addr is used in a non-standard context -- in the prologue
  7851  // of a function, before the frame has been constructed, so the standard
  7852  // addressing for the parameters will be wrong.
  7853  func SpillSlotAddr(spill ssa.Spill, baseReg int16, extraOffset int64) obj.Addr {
  7854  	return obj.Addr{
  7855  		Name:   obj.NAME_NONE,
  7856  		Type:   obj.TYPE_MEM,
  7857  		Reg:    baseReg,
  7858  		Offset: spill.Offset + extraOffset,
  7859  	}
  7860  }
  7861  
  7862  var (
  7863  	BoundsCheckFunc [ssa.BoundsKindCount]*obj.LSym
  7864  	ExtendCheckFunc [ssa.BoundsKindCount]*obj.LSym
  7865  )
  7866  
  7867  // GCWriteBarrierReg maps from registers to gcWriteBarrier implementation LSyms.
  7868  var GCWriteBarrierReg map[int16]*obj.LSym
  7869