objw.go

     1  // Copyright 2009 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 objw
     6  
     7  import (
     8  	"cmd/compile/internal/base"
     9  	"cmd/compile/internal/bitvec"
    10  	"cmd/compile/internal/types"
    11  	"cmd/internal/obj"
    12  )
    13  
    14  // Uint8 writes an unsigned byte v into s at offset off,
    15  // and returns the next unused offset (i.e., off+1).
    16  func Uint8(s *obj.LSym, off int, v uint8) int {
    17  	return UintN(s, off, uint64(v), 1)
    18  }
    19  
    20  func Uint16(s *obj.LSym, off int, v uint16) int {
    21  	return UintN(s, off, uint64(v), 2)
    22  }
    23  
    24  func Uint32(s *obj.LSym, off int, v uint32) int {
    25  	return UintN(s, off, uint64(v), 4)
    26  }
    27  
    28  func Uintptr(s *obj.LSym, off int, v uint64) int {
    29  	return UintN(s, off, v, types.PtrSize)
    30  }
    31  
    32  // UintN writes an unsigned integer v of size wid bytes into s at offset off,
    33  // and returns the next unused offset.
    34  func UintN(s *obj.LSym, off int, v uint64, wid int) int {
    35  	if off&(wid-1) != 0 {
    36  		base.Fatalf("duintxxLSym: misaligned: v=%d wid=%d off=%d", v, wid, off)
    37  	}
    38  	s.WriteInt(base.Ctxt, int64(off), wid, int64(v))
    39  	return off + wid
    40  }
    41  
    42  func SymPtr(s *obj.LSym, off int, x *obj.LSym, xoff int) int {
    43  	off = int(types.Rnd(int64(off), int64(types.PtrSize)))
    44  	s.WriteAddr(base.Ctxt, int64(off), types.PtrSize, x, int64(xoff))
    45  	off += types.PtrSize
    46  	return off
    47  }
    48  
    49  func SymPtrWeak(s *obj.LSym, off int, x *obj.LSym, xoff int) int {
    50  	off = int(types.Rnd(int64(off), int64(types.PtrSize)))
    51  	s.WriteWeakAddr(base.Ctxt, int64(off), types.PtrSize, x, int64(xoff))
    52  	off += types.PtrSize
    53  	return off
    54  }
    55  
    56  func SymPtrOff(s *obj.LSym, off int, x *obj.LSym) int {
    57  	s.WriteOff(base.Ctxt, int64(off), x, 0)
    58  	off += 4
    59  	return off
    60  }
    61  
    62  func SymPtrWeakOff(s *obj.LSym, off int, x *obj.LSym) int {
    63  	s.WriteWeakOff(base.Ctxt, int64(off), x, 0)
    64  	off += 4
    65  	return off
    66  }
    67  
    68  func Global(s *obj.LSym, width int32, flags int16) {
    69  	if flags&obj.LOCAL != 0 {
    70  		s.Set(obj.AttrLocal, true)
    71  		flags &^= obj.LOCAL
    72  	}
    73  	base.Ctxt.Globl(s, int64(width), int(flags))
    74  }
    75  
    76  // Bitvec writes the contents of bv into s as sequence of bytes
    77  // in little-endian order, and returns the next unused offset.
    78  func BitVec(s *obj.LSym, off int, bv bitvec.BitVec) int {
    79  	// Runtime reads the bitmaps as byte arrays. Oblige.
    80  	for j := 0; int32(j) < bv.N; j += 8 {
    81  		word := bv.B[j/32]
    82  		off = Uint8(s, off, uint8(word>>(uint(j)%32)))
    83  	}
    84  	return off
    85  }
    86
View as plain text