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cmd/objdump: copy gosym.PCValue into internal package

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... so we don't have to export gosym.PCValue.

Change-Id: Ie8f196d5e5ab63e3e69d1d7b4bfbbf32b7b5e4f5
Reviewed-on: https://go-review.googlesource.com/33791
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Keith Randall 2016-12-01 10:10:17 -08:00
parent 612469ab0b
commit 3c2e4ed8d3
3 changed files with 49 additions and 10 deletions
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51
src/cmd/internal/objfile/goobj.go
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@ -114,14 +114,14 @@ func (f *goobjFile) PCToLine(pc uint64) (string, int, *gosym.Func) {
if err != nil {
return "", 0, nil
}
fileID := gosym.PCValue(pcfile, pc-uint64(s.Data.Offset), arch.MinLC)
fileID := int(pcValue(pcfile, pc-uint64(s.Data.Offset), arch))
fileName := s.Func.File[fileID]
pcline := make([]byte, s.Func.PCLine.Size)
_, err = f.f.ReadAt(pcline, s.Func.PCLine.Offset)
if err != nil {
return "", 0, nil
}
line := gosym.PCValue(pcline, pc-uint64(s.Data.Offset), arch.MinLC)
line := int(pcValue(pcline, pc-uint64(s.Data.Offset), arch))
// Note: we provide only the name in the Func structure.
// We could provide more if needed.
return fileName, line, &gosym.Func{Sym: &gosym.Sym{Name: s.Name}}
@ -129,6 +129,53 @@ func (f *goobjFile) PCToLine(pc uint64) (string, int, *gosym.Func) {
return "", 0, nil
}
// pcValue looks up the given PC in a pc value table. target is the
// offset of the pc from the entry point.
func pcValue(tab []byte, target uint64, arch *sys.Arch) int32 {
val := int32(-1)
var pc uint64
for step(&tab, &pc, &val, pc == 0, arch) {
if target < pc {
return val
}
}
return -1
}
// step advances to the next pc, value pair in the encoded table.
func step(p *[]byte, pc *uint64, val *int32, first bool, arch *sys.Arch) bool {
uvdelta := readvarint(p)
if uvdelta == 0 && !first {
return false
}
if uvdelta&1 != 0 {
uvdelta = ^(uvdelta >> 1)
} else {
uvdelta >>= 1
}
vdelta := int32(uvdelta)
pcdelta := readvarint(p) * uint32(arch.MinLC)
*pc += uint64(pcdelta)
*val += vdelta
return true
}
// readvarint reads, removes, and returns a varint from *p.
func readvarint(p *[]byte) uint32 {
var v, shift uint32
s := *p
for shift = 0; ; shift += 7 {
b := s[0]
s = s[1:]
v |= (uint32(b) & 0x7F) << shift
if b&0x80 == 0 {
break
}
}
*p = s
return v
}
// We treat the whole object file as the text section.
func (f *goobjFile) text() (textStart uint64, text []byte, err error) {
var info os.FileInfo