config.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 ssa
     6  
     7  import (
     8  	"cmd/compile/internal/abi"
     9  	"cmd/compile/internal/ir"
    10  	"cmd/compile/internal/types"
    11  	"cmd/internal/obj"
    12  	"cmd/internal/src"
    13  	"internal/buildcfg"
    14  )
    15  
    16  // A Config holds readonly compilation information.
    17  // It is created once, early during compilation,
    18  // and shared across all compilations.
    19  type Config struct {
    20  	arch           string // "amd64", etc.
    21  	PtrSize        int64  // 4 or 8; copy of cmd/internal/sys.Arch.PtrSize
    22  	RegSize        int64  // 4 or 8; copy of cmd/internal/sys.Arch.RegSize
    23  	Types          Types
    24  	lowerBlock     blockRewriter  // lowering function
    25  	lowerValue     valueRewriter  // lowering function
    26  	splitLoad      valueRewriter  // function for splitting merged load ops; only used on some architectures
    27  	registers      []Register     // machine registers
    28  	gpRegMask      regMask        // general purpose integer register mask
    29  	fpRegMask      regMask        // floating point register mask
    30  	fp32RegMask    regMask        // floating point register mask
    31  	fp64RegMask    regMask        // floating point register mask
    32  	specialRegMask regMask        // special register mask
    33  	intParamRegs   []int8         // register numbers of integer param (in/out) registers
    34  	floatParamRegs []int8         // register numbers of floating param (in/out) registers
    35  	ABI1           *abi.ABIConfig // "ABIInternal" under development // TODO change comment when this becomes current
    36  	ABI0           *abi.ABIConfig
    37  	GCRegMap       []*Register // garbage collector register map, by GC register index
    38  	FPReg          int8        // register number of frame pointer, -1 if not used
    39  	LinkReg        int8        // register number of link register if it is a general purpose register, -1 if not used
    40  	hasGReg        bool        // has hardware g register
    41  	ctxt           *obj.Link   // Generic arch information
    42  	optimize       bool        // Do optimization
    43  	noDuffDevice   bool        // Don't use Duff's device
    44  	useSSE         bool        // Use SSE for non-float operations
    45  	useAvg         bool        // Use optimizations that need Avg* operations
    46  	useHmul        bool        // Use optimizations that need Hmul* operations
    47  	SoftFloat      bool        //
    48  	Race           bool        // race detector enabled
    49  	BigEndian      bool        //
    50  	UseFMA         bool        // Use hardware FMA operation
    51  }
    52  
    53  type (
    54  	blockRewriter func(*Block) bool
    55  	valueRewriter func(*Value) bool
    56  )
    57  
    58  type Types struct {
    59  	Bool       *types.Type
    60  	Int8       *types.Type
    61  	Int16      *types.Type
    62  	Int32      *types.Type
    63  	Int64      *types.Type
    64  	UInt8      *types.Type
    65  	UInt16     *types.Type
    66  	UInt32     *types.Type
    67  	UInt64     *types.Type
    68  	Int        *types.Type
    69  	Float32    *types.Type
    70  	Float64    *types.Type
    71  	UInt       *types.Type
    72  	Uintptr    *types.Type
    73  	String     *types.Type
    74  	BytePtr    *types.Type // TODO: use unsafe.Pointer instead?
    75  	Int32Ptr   *types.Type
    76  	UInt32Ptr  *types.Type
    77  	IntPtr     *types.Type
    78  	UintptrPtr *types.Type
    79  	Float32Ptr *types.Type
    80  	Float64Ptr *types.Type
    81  	BytePtrPtr *types.Type
    82  }
    83  
    84  // NewTypes creates and populates a Types.
    85  func NewTypes() *Types {
    86  	t := new(Types)
    87  	t.SetTypPtrs()
    88  	return t
    89  }
    90  
    91  // SetTypPtrs populates t.
    92  func (t *Types) SetTypPtrs() {
    93  	t.Bool = types.Types[types.TBOOL]
    94  	t.Int8 = types.Types[types.TINT8]
    95  	t.Int16 = types.Types[types.TINT16]
    96  	t.Int32 = types.Types[types.TINT32]
    97  	t.Int64 = types.Types[types.TINT64]
    98  	t.UInt8 = types.Types[types.TUINT8]
    99  	t.UInt16 = types.Types[types.TUINT16]
   100  	t.UInt32 = types.Types[types.TUINT32]
   101  	t.UInt64 = types.Types[types.TUINT64]
   102  	t.Int = types.Types[types.TINT]
   103  	t.Float32 = types.Types[types.TFLOAT32]
   104  	t.Float64 = types.Types[types.TFLOAT64]
   105  	t.UInt = types.Types[types.TUINT]
   106  	t.Uintptr = types.Types[types.TUINTPTR]
   107  	t.String = types.Types[types.TSTRING]
   108  	t.BytePtr = types.NewPtr(types.Types[types.TUINT8])
   109  	t.Int32Ptr = types.NewPtr(types.Types[types.TINT32])
   110  	t.UInt32Ptr = types.NewPtr(types.Types[types.TUINT32])
   111  	t.IntPtr = types.NewPtr(types.Types[types.TINT])
   112  	t.UintptrPtr = types.NewPtr(types.Types[types.TUINTPTR])
   113  	t.Float32Ptr = types.NewPtr(types.Types[types.TFLOAT32])
   114  	t.Float64Ptr = types.NewPtr(types.Types[types.TFLOAT64])
   115  	t.BytePtrPtr = types.NewPtr(types.NewPtr(types.Types[types.TUINT8]))
   116  }
   117  
   118  type Logger interface {
   119  	// Logf logs a message from the compiler.
   120  	Logf(string, ...interface{})
   121  
   122  	// Log reports whether logging is not a no-op
   123  	// some logging calls account for more than a few heap allocations.
   124  	Log() bool
   125  
   126  	// Fatal reports a compiler error and exits.
   127  	Fatalf(pos src.XPos, msg string, args ...interface{})
   128  
   129  	// Warnl writes compiler messages in the form expected by "errorcheck" tests
   130  	Warnl(pos src.XPos, fmt_ string, args ...interface{})
   131  
   132  	// Forwards the Debug flags from gc
   133  	Debug_checknil() bool
   134  }
   135  
   136  type Frontend interface {
   137  	CanSSA(t *types.Type) bool
   138  
   139  	Logger
   140  
   141  	// StringData returns a symbol pointing to the given string's contents.
   142  	StringData(string) *obj.LSym
   143  
   144  	// Auto returns a Node for an auto variable of the given type.
   145  	// The SSA compiler uses this function to allocate space for spills.
   146  	Auto(src.XPos, *types.Type) *ir.Name
   147  
   148  	// Given the name for a compound type, returns the name we should use
   149  	// for the parts of that compound type.
   150  	SplitSlot(parent *LocalSlot, suffix string, offset int64, t *types.Type) LocalSlot
   151  
   152  	// Line returns a string describing the given position.
   153  	Line(src.XPos) string
   154  
   155  	// AllocFrame assigns frame offsets to all live auto variables.
   156  	AllocFrame(f *Func)
   157  
   158  	// Syslook returns a symbol of the runtime function/variable with the
   159  	// given name.
   160  	Syslook(string) *obj.LSym
   161  
   162  	// UseWriteBarrier reports whether write barrier is enabled
   163  	UseWriteBarrier() bool
   164  
   165  	// SetWBPos indicates that a write barrier has been inserted
   166  	// in this function at position pos.
   167  	SetWBPos(pos src.XPos)
   168  
   169  	// MyImportPath provides the import name (roughly, the package) for the function being compiled.
   170  	MyImportPath() string
   171  }
   172  
   173  // NewConfig returns a new configuration object for the given architecture.
   174  func NewConfig(arch string, types Types, ctxt *obj.Link, optimize, softfloat bool) *Config {
   175  	c := &Config{arch: arch, Types: types}
   176  	c.useAvg = true
   177  	c.useHmul = true
   178  	switch arch {
   179  	case "amd64":
   180  		c.PtrSize = 8
   181  		c.RegSize = 8
   182  		c.lowerBlock = rewriteBlockAMD64
   183  		c.lowerValue = rewriteValueAMD64
   184  		c.splitLoad = rewriteValueAMD64splitload
   185  		c.registers = registersAMD64[:]
   186  		c.gpRegMask = gpRegMaskAMD64
   187  		c.fpRegMask = fpRegMaskAMD64
   188  		c.specialRegMask = specialRegMaskAMD64
   189  		c.intParamRegs = paramIntRegAMD64
   190  		c.floatParamRegs = paramFloatRegAMD64
   191  		c.FPReg = framepointerRegAMD64
   192  		c.LinkReg = linkRegAMD64
   193  		c.hasGReg = true
   194  	case "386":
   195  		c.PtrSize = 4
   196  		c.RegSize = 4
   197  		c.lowerBlock = rewriteBlock386
   198  		c.lowerValue = rewriteValue386
   199  		c.splitLoad = rewriteValue386splitload
   200  		c.registers = registers386[:]
   201  		c.gpRegMask = gpRegMask386
   202  		c.fpRegMask = fpRegMask386
   203  		c.FPReg = framepointerReg386
   204  		c.LinkReg = linkReg386
   205  		c.hasGReg = false
   206  	case "arm":
   207  		c.PtrSize = 4
   208  		c.RegSize = 4
   209  		c.lowerBlock = rewriteBlockARM
   210  		c.lowerValue = rewriteValueARM
   211  		c.registers = registersARM[:]
   212  		c.gpRegMask = gpRegMaskARM
   213  		c.fpRegMask = fpRegMaskARM
   214  		c.FPReg = framepointerRegARM
   215  		c.LinkReg = linkRegARM
   216  		c.hasGReg = true
   217  	case "arm64":
   218  		c.PtrSize = 8
   219  		c.RegSize = 8
   220  		c.lowerBlock = rewriteBlockARM64
   221  		c.lowerValue = rewriteValueARM64
   222  		c.registers = registersARM64[:]
   223  		c.gpRegMask = gpRegMaskARM64
   224  		c.fpRegMask = fpRegMaskARM64
   225  		c.intParamRegs = paramIntRegARM64
   226  		c.floatParamRegs = paramFloatRegARM64
   227  		c.FPReg = framepointerRegARM64
   228  		c.LinkReg = linkRegARM64
   229  		c.hasGReg = true
   230  		c.noDuffDevice = buildcfg.GOOS == "darwin" || buildcfg.GOOS == "ios" // darwin linker cannot handle BR26 reloc with non-zero addend
   231  	case "ppc64":
   232  		c.BigEndian = true
   233  		fallthrough
   234  	case "ppc64le":
   235  		c.PtrSize = 8
   236  		c.RegSize = 8
   237  		c.lowerBlock = rewriteBlockPPC64
   238  		c.lowerValue = rewriteValuePPC64
   239  		c.registers = registersPPC64[:]
   240  		c.gpRegMask = gpRegMaskPPC64
   241  		c.fpRegMask = fpRegMaskPPC64
   242  		c.intParamRegs = paramIntRegPPC64
   243  		c.floatParamRegs = paramFloatRegPPC64
   244  		c.FPReg = framepointerRegPPC64
   245  		c.LinkReg = linkRegPPC64
   246  		c.hasGReg = true
   247  	case "mips64":
   248  		c.BigEndian = true
   249  		fallthrough
   250  	case "mips64le":
   251  		c.PtrSize = 8
   252  		c.RegSize = 8
   253  		c.lowerBlock = rewriteBlockMIPS64
   254  		c.lowerValue = rewriteValueMIPS64
   255  		c.registers = registersMIPS64[:]
   256  		c.gpRegMask = gpRegMaskMIPS64
   257  		c.fpRegMask = fpRegMaskMIPS64
   258  		c.specialRegMask = specialRegMaskMIPS64
   259  		c.FPReg = framepointerRegMIPS64
   260  		c.LinkReg = linkRegMIPS64
   261  		c.hasGReg = true
   262  	case "s390x":
   263  		c.PtrSize = 8
   264  		c.RegSize = 8
   265  		c.lowerBlock = rewriteBlockS390X
   266  		c.lowerValue = rewriteValueS390X
   267  		c.registers = registersS390X[:]
   268  		c.gpRegMask = gpRegMaskS390X
   269  		c.fpRegMask = fpRegMaskS390X
   270  		c.FPReg = framepointerRegS390X
   271  		c.LinkReg = linkRegS390X
   272  		c.hasGReg = true
   273  		c.noDuffDevice = true
   274  		c.BigEndian = true
   275  	case "mips":
   276  		c.BigEndian = true
   277  		fallthrough
   278  	case "mipsle":
   279  		c.PtrSize = 4
   280  		c.RegSize = 4
   281  		c.lowerBlock = rewriteBlockMIPS
   282  		c.lowerValue = rewriteValueMIPS
   283  		c.registers = registersMIPS[:]
   284  		c.gpRegMask = gpRegMaskMIPS
   285  		c.fpRegMask = fpRegMaskMIPS
   286  		c.specialRegMask = specialRegMaskMIPS
   287  		c.FPReg = framepointerRegMIPS
   288  		c.LinkReg = linkRegMIPS
   289  		c.hasGReg = true
   290  		c.noDuffDevice = true
   291  	case "riscv64":
   292  		c.PtrSize = 8
   293  		c.RegSize = 8
   294  		c.lowerBlock = rewriteBlockRISCV64
   295  		c.lowerValue = rewriteValueRISCV64
   296  		c.registers = registersRISCV64[:]
   297  		c.gpRegMask = gpRegMaskRISCV64
   298  		c.fpRegMask = fpRegMaskRISCV64
   299  		c.FPReg = framepointerRegRISCV64
   300  		c.hasGReg = true
   301  	case "wasm":
   302  		c.PtrSize = 8
   303  		c.RegSize = 8
   304  		c.lowerBlock = rewriteBlockWasm
   305  		c.lowerValue = rewriteValueWasm
   306  		c.registers = registersWasm[:]
   307  		c.gpRegMask = gpRegMaskWasm
   308  		c.fpRegMask = fpRegMaskWasm
   309  		c.fp32RegMask = fp32RegMaskWasm
   310  		c.fp64RegMask = fp64RegMaskWasm
   311  		c.FPReg = framepointerRegWasm
   312  		c.LinkReg = linkRegWasm
   313  		c.hasGReg = true
   314  		c.noDuffDevice = true
   315  		c.useAvg = false
   316  		c.useHmul = false
   317  	default:
   318  		ctxt.Diag("arch %s not implemented", arch)
   319  	}
   320  	c.ctxt = ctxt
   321  	c.optimize = optimize
   322  	c.useSSE = true
   323  	c.UseFMA = true
   324  	c.SoftFloat = softfloat
   325  	if softfloat {
   326  		c.floatParamRegs = nil // no FP registers in softfloat mode
   327  	}
   328  
   329  	c.ABI0 = abi.NewABIConfig(0, 0, ctxt.FixedFrameSize())
   330  	c.ABI1 = abi.NewABIConfig(len(c.intParamRegs), len(c.floatParamRegs), ctxt.FixedFrameSize())
   331  
   332  	// On Plan 9, floating point operations are not allowed in note handler.
   333  	if buildcfg.GOOS == "plan9" {
   334  		// Don't use FMA on Plan 9
   335  		c.UseFMA = false
   336  
   337  		// Don't use Duff's device and SSE on Plan 9 AMD64.
   338  		if arch == "amd64" {
   339  			c.noDuffDevice = true
   340  			c.useSSE = false
   341  		}
   342  	}
   343  
   344  	if ctxt.Flag_shared {
   345  		// LoweredWB is secretly a CALL and CALLs on 386 in
   346  		// shared mode get rewritten by obj6.go to go through
   347  		// the GOT, which clobbers BX.
   348  		opcodeTable[Op386LoweredWB].reg.clobbers |= 1 << 3 // BX
   349  	}
   350  
   351  	// Create the GC register map index.
   352  	// TODO: This is only used for debug printing. Maybe export config.registers?
   353  	gcRegMapSize := int16(0)
   354  	for _, r := range c.registers {
   355  		if r.gcNum+1 > gcRegMapSize {
   356  			gcRegMapSize = r.gcNum + 1
   357  		}
   358  	}
   359  	c.GCRegMap = make([]*Register, gcRegMapSize)
   360  	for i, r := range c.registers {
   361  		if r.gcNum != -1 {
   362  			c.GCRegMap[r.gcNum] = &c.registers[i]
   363  		}
   364  	}
   365  
   366  	return c
   367  }
   368  
   369  func (c *Config) Ctxt() *obj.Link { return c.ctxt }
   370
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