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cmd/link: support dwarf64 when writing .debug_frame

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Fixes #28558

Change-Id: I0ecd9c47fb017cf4bd44725a83a0016c7bb94633
Reviewed-on: https://go-review.googlesource.com/c/go/+/156478
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
Clément Chigot 2019-01-07 10:22:42 +01:00 • committed by Ian Lance Taylor
parent 53d859bdf5
commit ed2fce2d87
1 changed files with 19 additions and 5 deletions
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24
src/cmd/link/internal/ld/dwarf.go
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@ -1391,13 +1391,22 @@ func writeframes(ctxt *Link, syms []*sym.Symbol) []*sym.Symbol {
fs.Type = sym.SDWARFSECT fs.Type = sym.SDWARFSECT
syms = append(syms, fs) syms = append(syms, fs)
// Length field is 4 bytes on Dwarf32 and 12 bytes on Dwarf64
lengthFieldSize := int64(4)
if isDwarf64(ctxt) {
lengthFieldSize += 8
}
// Emit the CIE, Section 6.4.1 // Emit the CIE, Section 6.4.1
cieReserve := uint32(16) cieReserve := uint32(16)
if haslinkregister(ctxt) { if haslinkregister(ctxt) {
cieReserve = 32 cieReserve = 32
} }
if isDwarf64(ctxt) {
cieReserve += 4 // 4 bytes added for cid
}
createUnitLength(ctxt, fs, uint64(cieReserve)) // initial length, must be multiple of thearch.ptrsize createUnitLength(ctxt, fs, uint64(cieReserve)) // initial length, must be multiple of thearch.ptrsize
addDwarfAddrField(ctxt, fs, 0xffffffff) // cid. addDwarfAddrField(ctxt, fs, ^uint64(0)) // cid
fs.AddUint8(3) // dwarf version (appendix F) fs.AddUint8(3) // dwarf version (appendix F)
fs.AddUint8(0) // augmentation "" fs.AddUint8(0) // augmentation ""
dwarf.Uleb128put(dwarfctxt, fs, 1) // code_alignment_factor dwarf.Uleb128put(dwarfctxt, fs, 1) // code_alignment_factor
@ -1423,8 +1432,7 @@ func writeframes(ctxt *Link, syms []*sym.Symbol) []*sym.Symbol {
dwarf.Uleb128put(dwarfctxt, fs, int64(-ctxt.Arch.PtrSize)/dataAlignmentFactor) // ...is saved at [CFA - (PtrSize/4)]. dwarf.Uleb128put(dwarfctxt, fs, int64(-ctxt.Arch.PtrSize)/dataAlignmentFactor) // ...is saved at [CFA - (PtrSize/4)].
} }
// 4 is to exclude the length field. pad := int64(cieReserve) + lengthFieldSize - fs.Size
pad := int64(cieReserve) + 4 - fs.Size
if pad < 0 { if pad < 0 {
Exitf("dwarf: cieReserve too small by %d bytes.", -pad) Exitf("dwarf: cieReserve too small by %d bytes.", -pad)
@ -1480,10 +1488,16 @@ func writeframes(ctxt *Link, syms []*sym.Symbol) []*sym.Symbol {
// Emit the FDE header, Section 6.4.1. // Emit the FDE header, Section 6.4.1.
// 4 bytes: length, must be multiple of thearch.ptrsize // 4 bytes: length, must be multiple of thearch.ptrsize
// 4 bytes: Pointer to the CIE above, at offset 0 // 4/8 bytes: Pointer to the CIE above, at offset 0
// ptrsize: initial location // ptrsize: initial location
// ptrsize: address range // ptrsize: address range
fs.AddUint32(ctxt.Arch, uint32(4+2*ctxt.Arch.PtrSize+len(deltaBuf))) // length (excludes itself)
fdeLength := uint64(4 + 2*ctxt.Arch.PtrSize + len(deltaBuf))
if isDwarf64(ctxt) {
fdeLength += 4 // 4 bytes added for CIE pointer
}
createUnitLength(ctxt, fs, fdeLength)
if ctxt.LinkMode == LinkExternal { if ctxt.LinkMode == LinkExternal {
addDwarfAddrRef(ctxt, fs, fs) addDwarfAddrRef(ctxt, fs, fs)
} else { } else {