[llvm] r181910 - Cleanup relocation sorting for ELF.
Rafael Espindola
rafael.espindola at gmail.com
Wed May 15 11:22:01 PDT 2013
Author: rafael
Date: Wed May 15 13:22:01 2013
New Revision: 181910
URL: http://llvm.org/viewvc/llvm-project?rev=181910&view=rev
Log:
Cleanup relocation sorting for ELF.
We want the order to be deterministic on all platforms. NAKAMURA Takumi
fixed that in r181864. This patch is just two small cleanups:
* Move the function to the cpp file. It is only passed to array_pod_sort.
* Remove the ppc implementation which is now redundant
Modified:
llvm/trunk/include/llvm/MC/MCELFObjectWriter.h
llvm/trunk/lib/MC/MCELFObjectTargetWriter.cpp
llvm/trunk/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
Modified: llvm/trunk/include/llvm/MC/MCELFObjectWriter.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCELFObjectWriter.h?rev=181910&r1=181909&r2=181910&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCELFObjectWriter.h (original)
+++ llvm/trunk/include/llvm/MC/MCELFObjectWriter.h Wed May 15 13:22:01 2013
@@ -42,18 +42,6 @@ struct ELFRelocationEntry {
const MCSymbol *Sym, uint64_t Addend, const MCFixup &Fixup)
: r_offset(RelocOffset), Index(Idx), Type(RelType), Symbol(Sym),
r_addend(Addend), Fixup(&Fixup) {}
-
- // Support lexicographic sorting.
- bool operator<(const ELFRelocationEntry &RE) const {
- if (RE.r_offset != r_offset)
- return RE.r_offset < r_offset;
- if (Type != RE.Type)
- return Type < RE.Type;
- if (Index != RE.Index)
- return Index < RE.Index;
- llvm_unreachable("ELFRelocs might be unstable!");
- return 0;
- }
};
class MCELFObjectTargetWriter {
Modified: llvm/trunk/lib/MC/MCELFObjectTargetWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCELFObjectTargetWriter.cpp?rev=181910&r1=181909&r2=181910&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCELFObjectTargetWriter.cpp (original)
+++ llvm/trunk/lib/MC/MCELFObjectTargetWriter.cpp Wed May 15 13:22:01 2013
@@ -39,9 +39,23 @@ const MCSymbol *MCELFObjectTargetWriter:
return &Symbol.AliasedSymbol();
}
+// ELF doesn't require relocations to be in any order. We sort by the r_offset,
+// just to match gnu as for easier comparison. The use type and index is an
+// arbitrary way of making the sort deterministic.
+static int cmpRel(const void *AP, const void *BP) {
+ const ELFRelocationEntry &A = *(const ELFRelocationEntry *)AP;
+ const ELFRelocationEntry &B = *(const ELFRelocationEntry *)BP;
+ if (A.r_offset != B.r_offset)
+ return B.r_offset - A.r_offset;
+ if (B.Type != A.Type)
+ return A.Type - B.Type;
+ if (B.Index != A.Index)
+ return B.Index - A.Index;
+ llvm_unreachable("ELFRelocs might be unstable!");
+}
+
void
MCELFObjectTargetWriter::sortRelocs(const MCAssembler &Asm,
std::vector<ELFRelocationEntry> &Relocs) {
- // Sort by the r_offset, just like gnu as does.
- array_pod_sort(Relocs.begin(), Relocs.end());
+ array_pod_sort(Relocs.begin(), Relocs.end(), cmpRel);
}
Modified: llvm/trunk/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp?rev=181910&r1=181909&r2=181910&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp Wed May 15 13:22:01 2013
@@ -33,25 +33,9 @@ namespace {
virtual const MCSymbol *undefinedExplicitRelSym(const MCValue &Target,
const MCFixup &Fixup,
bool IsPCRel) const;
-
- virtual void sortRelocs(const MCAssembler &Asm,
- std::vector<ELFRelocationEntry> &Relocs);
- };
-
- class PPCELFRelocationEntry : public ELFRelocationEntry {
- public:
- PPCELFRelocationEntry(const ELFRelocationEntry &RE);
- bool operator<(const PPCELFRelocationEntry &RE) const {
- return (RE.r_offset < r_offset ||
- (RE.r_offset == r_offset && RE.Type > Type));
- }
};
}
-PPCELFRelocationEntry::PPCELFRelocationEntry(const ELFRelocationEntry &RE)
- : ELFRelocationEntry(RE.r_offset, RE.Index, RE.Type, RE.Symbol,
- RE.r_addend, *RE.Fixup) {}
-
PPCELFObjectWriter::PPCELFObjectWriter(bool Is64Bit, uint8_t OSABI)
: MCELFObjectTargetWriter(Is64Bit, OSABI,
Is64Bit ? ELF::EM_PPC64 : ELF::EM_PPC,
@@ -239,34 +223,6 @@ const MCSymbol *PPCELFObjectWriter::unde
return NULL;
}
-// The standard sorter only sorts on the r_offset field, but PowerPC can
-// have multiple relocations at the same offset. Sort secondarily on the
-// relocation type to avoid nondeterminism.
-void PPCELFObjectWriter::sortRelocs(const MCAssembler &Asm,
- std::vector<ELFRelocationEntry> &Relocs) {
-
- // Copy to a temporary vector of relocation entries having a different
- // sort function.
- std::vector<PPCELFRelocationEntry> TmpRelocs;
-
- for (std::vector<ELFRelocationEntry>::iterator R = Relocs.begin();
- R != Relocs.end(); ++R) {
- TmpRelocs.push_back(PPCELFRelocationEntry(*R));
- }
-
- // Sort in place by ascending r_offset and descending r_type.
- array_pod_sort(TmpRelocs.begin(), TmpRelocs.end());
-
- // Copy back to the original vector.
- unsigned I = 0;
- for (std::vector<PPCELFRelocationEntry>::iterator R = TmpRelocs.begin();
- R != TmpRelocs.end(); ++R, ++I) {
- Relocs[I] = ELFRelocationEntry(R->r_offset, R->Index, R->Type,
- R->Symbol, R->r_addend, *R->Fixup);
- }
-}
-
-
MCObjectWriter *llvm::createPPCELFObjectWriter(raw_ostream &OS,
bool Is64Bit,
uint8_t OSABI) {
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