site/vendor/github.com/google/gops/internal/obj/data.go

191 lines
5.6 KiB
Go

// Derived from Inferno utils/6l/obj.c and utils/6l/span.c
// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/obj.c
// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/span.c
//
// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
// Portions Copyright © 1997-1999 Vita Nuova Limited
// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
// Portions Copyright © 2004,2006 Bruce Ellis
// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
// Portions Copyright © 2009 The Go Authors. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package obj
import (
"log"
"math"
)
// Grow increases the length of s.P to lsiz.
func (s *LSym) Grow(lsiz int64) {
siz := int(lsiz)
if int64(siz) != lsiz {
log.Fatalf("LSym.Grow size %d too long", lsiz)
}
if len(s.P) >= siz {
return
}
// TODO(dfc) append cap-len at once, rather than
// one byte at a time.
for cap(s.P) < siz {
s.P = append(s.P[:cap(s.P)], 0)
}
s.P = s.P[:siz]
}
// GrowCap increases the capacity of s.P to c.
func (s *LSym) GrowCap(c int64) {
if int64(cap(s.P)) >= c {
return
}
if s.P == nil {
s.P = make([]byte, 0, c)
return
}
b := make([]byte, len(s.P), c)
copy(b, s.P)
s.P = b
}
// prepwrite prepares to write data of size siz into s at offset off.
func (s *LSym) prepwrite(ctxt *Link, off int64, siz int) {
if off < 0 || siz < 0 || off >= 1<<30 {
log.Fatalf("prepwrite: bad off=%d siz=%d", off, siz)
}
if s.Type == SBSS || s.Type == STLSBSS {
ctxt.Diag("cannot supply data for BSS var")
}
l := off + int64(siz)
s.Grow(l)
if l > s.Size {
s.Size = l
}
}
// WriteFloat32 writes f into s at offset off.
func (s *LSym) WriteFloat32(ctxt *Link, off int64, f float32) {
s.prepwrite(ctxt, off, 4)
ctxt.Arch.ByteOrder.PutUint32(s.P[off:], math.Float32bits(f))
}
// WriteFloat64 writes f into s at offset off.
func (s *LSym) WriteFloat64(ctxt *Link, off int64, f float64) {
s.prepwrite(ctxt, off, 8)
ctxt.Arch.ByteOrder.PutUint64(s.P[off:], math.Float64bits(f))
}
// WriteInt writes an integer i of size siz into s at offset off.
func (s *LSym) WriteInt(ctxt *Link, off int64, siz int, i int64) {
s.prepwrite(ctxt, off, siz)
switch siz {
default:
ctxt.Diag("WriteInt: bad integer size: %d", siz)
case 1:
s.P[off] = byte(i)
case 2:
ctxt.Arch.ByteOrder.PutUint16(s.P[off:], uint16(i))
case 4:
ctxt.Arch.ByteOrder.PutUint32(s.P[off:], uint32(i))
case 8:
ctxt.Arch.ByteOrder.PutUint64(s.P[off:], uint64(i))
}
}
// WriteAddr writes an address of size siz into s at offset off.
// rsym and roff specify the relocation for the address.
func (s *LSym) WriteAddr(ctxt *Link, off int64, siz int, rsym *LSym, roff int64) {
if siz != ctxt.Arch.PtrSize {
ctxt.Diag("WriteAddr: bad address size %d in %s", siz, s.Name)
}
s.prepwrite(ctxt, off, siz)
r := Addrel(s)
r.Off = int32(off)
if int64(r.Off) != off {
ctxt.Diag("WriteAddr: off overflow %d in %s", off, s.Name)
}
r.Siz = uint8(siz)
r.Sym = rsym
r.Type = R_ADDR
r.Add = roff
}
// WriteOff writes a 4 byte offset to rsym+roff into s at offset off.
// After linking the 4 bytes stored at s+off will be
// rsym+roff-(start of section that s is in).
func (s *LSym) WriteOff(ctxt *Link, off int64, rsym *LSym, roff int64) {
s.prepwrite(ctxt, off, 4)
r := Addrel(s)
r.Off = int32(off)
if int64(r.Off) != off {
ctxt.Diag("WriteOff: off overflow %d in %s", off, s.Name)
}
r.Siz = 4
r.Sym = rsym
r.Type = R_ADDROFF
r.Add = roff
}
// WriteString writes a string of size siz into s at offset off.
func (s *LSym) WriteString(ctxt *Link, off int64, siz int, str string) {
if siz < len(str) {
ctxt.Diag("WriteString: bad string size: %d < %d", siz, len(str))
}
s.prepwrite(ctxt, off, siz)
copy(s.P[off:off+int64(siz)], str)
}
// WriteBytes writes a slice of bytes into s at offset off.
func (s *LSym) WriteBytes(ctxt *Link, off int64, b []byte) int64 {
s.prepwrite(ctxt, off, len(b))
copy(s.P[off:], b)
return off + int64(len(b))
}
func Addrel(s *LSym) *Reloc {
s.R = append(s.R, Reloc{})
return &s.R[len(s.R)-1]
}
func Setuintxx(ctxt *Link, s *LSym, off int64, v uint64, wid int64) int64 {
if s.Type == 0 {
s.Type = SDATA
}
if s.Size < off+wid {
s.Size = off + wid
s.Grow(s.Size)
}
switch wid {
case 1:
s.P[off] = uint8(v)
case 2:
ctxt.Arch.ByteOrder.PutUint16(s.P[off:], uint16(v))
case 4:
ctxt.Arch.ByteOrder.PutUint32(s.P[off:], uint32(v))
case 8:
ctxt.Arch.ByteOrder.PutUint64(s.P[off:], v)
}
return off + wid
}