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Avoid explicit relocation sorting most of the time.

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These days relocations are created and stored in a deterministic way.
The order they are created is also suitable for the .o file, so we don't
need an explicit sort.

The last remaining exception is MIPS.

llvm-svn: 255902
This commit is contained in:
Rafael Espindola
2015-12-17 16:22:06 +00:00
parent ad57992887
commit f44db24e1f
8 changed files with 32 additions and 45 deletions
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23
llvm/lib/MC/ELFObjectWriter.cpp
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@@ -1046,28 +1046,17 @@ void ELFObjectWriter::WriteSecHdrEntry(uint32_t Name, uint32_t Type,
WriteWord(EntrySize); // sh_entsize
}
// ELF doesn't require relocations to be in any order. We sort by the Offset,
// just to match gnu as for easier comparison. The use type is an arbitrary way
// of making the sort deterministic.
static int cmpRel(const ELFRelocationEntry *AP, const ELFRelocationEntry *BP) {
const ELFRelocationEntry &A = *AP;
const ELFRelocationEntry &B = *BP;
if (A.Offset != B.Offset)
return B.Offset - A.Offset;
if (B.Type != A.Type)
return A.Type - B.Type;
llvm_unreachable("ELFRelocs might be unstable!");
return 0;
}
void ELFObjectWriter::writeRelocations(const MCAssembler &Asm,
const MCSectionELF &Sec) {
std::vector<ELFRelocationEntry> &Relocs = Relocations[&Sec];
array_pod_sort(Relocs.begin(), Relocs.end(), cmpRel);
// We record relocations by pushing to the end of a vector. Reverse the vector
// to get the relocations in the order they were created.
// In most cases that is not important, but it can be for special sections
// (.eh_frame) or specific relocations (TLS optimizations on SystemZ).
std::reverse(Relocs.begin(), Relocs.end());
// Sort the relocation entries. Most targets just sort by Offset, but some
// (e.g., MIPS) have additional constraints.
// Sort the relocation entries. MIPS needs this.
TargetObjectWriter->sortRelocs(Asm, Relocs);
for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {