Avoid an extra walk over the sections just to assign sections to groups.

Assign the sections in the same pass we compute the index.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236045 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Rafael Espindola 2015-04-28 21:52:33 +00:00
parent 642098ac59
commit f23613a3cd

View File

@ -231,7 +231,13 @@ class ELFObjectWriter : public MCObjectWriter {
const SectionIndexMapTy &SectionIndexMap,
const RevGroupMapTy &RevGroupMap);
void computeIndexMap(MCAssembler &Asm, SectionIndexMapTy &SectionIndexMap);
void maybeAddToGroup(MCAssembler &Asm, const RevGroupMapTy &RevGroupMap,
const MCSectionELF &Section, unsigned Index);
void computeIndexMap(MCAssembler &Asm,
std::vector<const MCSectionELF *> &Sections,
SectionIndexMapTy &SectionIndexMap,
const RevGroupMapTy &RevGroupMap);
MCSectionData *createRelocationSection(MCAssembler &Asm,
const MCSectionData &SD);
@ -247,6 +253,7 @@ class ELFObjectWriter : public MCObjectWriter {
// those are the .note.GNU-stack section and the group sections.
void createIndexedSections(MCAssembler &Asm, MCAsmLayout &Layout,
RevGroupMapTy &RevGroupMap,
std::vector<const MCSectionELF *> &Sections,
SectionIndexMapTy &SectionIndexMap);
void ExecutePostLayoutBinding(MCAssembler &Asm,
@ -933,15 +940,30 @@ bool ELFObjectWriter::isLocal(const MCSymbolData &Data, bool isUsedInReloc) {
return true;
}
void ELFObjectWriter::computeIndexMap(MCAssembler &Asm,
SectionIndexMapTy &SectionIndexMap) {
unsigned Index = 1;
void ELFObjectWriter::maybeAddToGroup(MCAssembler &Asm,
const RevGroupMapTy &RevGroupMap,
const MCSectionELF &Section,
unsigned Index) {
const MCSymbol *Sym = Section.getGroup();
if (!Sym)
return;
const MCSectionELF *Group = RevGroupMap.lookup(Sym);
MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
// FIXME: we could use the previous fragment
MCDataFragment *F = new MCDataFragment(&Data);
write(*F, Index);
}
void ELFObjectWriter::computeIndexMap(
MCAssembler &Asm, std::vector<const MCSectionELF *> &Sections,
SectionIndexMapTy &SectionIndexMap, const RevGroupMapTy &RevGroupMap) {
for (const MCSectionData &SD : Asm) {
const MCSectionELF &Section =
static_cast<const MCSectionELF &>(SD.getSection());
if (Section.getType() != ELF::SHT_GROUP)
continue;
SectionIndexMap[&Section] = Index++;
Sections.push_back(&Section);
SectionIndexMap[&Section] = Sections.size();
}
std::vector<const MCSectionELF *> RelSections;
@ -952,7 +974,11 @@ void ELFObjectWriter::computeIndexMap(MCAssembler &Asm,
Section.getType() == ELF::SHT_REL ||
Section.getType() == ELF::SHT_RELA)
continue;
SectionIndexMap[&Section] = Index++;
Sections.push_back(&Section);
unsigned Index = Sections.size();
SectionIndexMap[&Section] = Index;
maybeAddToGroup(Asm, RevGroupMap, Section, Index);
if (MCSectionData *RelSD = createRelocationSection(Asm, SD)) {
const MCSectionELF *RelSection =
static_cast<const MCSectionELF *>(&RelSD->getSection());
@ -962,8 +988,11 @@ void ELFObjectWriter::computeIndexMap(MCAssembler &Asm,
// Put relocation sections close together. The linker reads them
// first, so this improves cache locality.
for (const MCSectionELF * Sec: RelSections)
SectionIndexMap[Sec] = Index++;
for (const MCSectionELF *Sec : RelSections) {
Sections.push_back(Sec);
unsigned Index = Sections.size();
maybeAddToGroup(Asm, RevGroupMap, *Sec, Index);
}
}
void ELFObjectWriter::computeSymbolTable(
@ -1420,6 +1449,7 @@ void ELFObjectWriter::CreateMetadataSections(
void ELFObjectWriter::createIndexedSections(
MCAssembler &Asm, MCAsmLayout &Layout, RevGroupMapTy &RevGroupMap,
std::vector<const MCSectionELF *> &Sections,
SectionIndexMapTy &SectionIndexMap) {
MCContext &Ctx = Asm.getContext();
@ -1443,22 +1473,7 @@ void ELFObjectWriter::createIndexedSections(
}
}
computeIndexMap(Asm, SectionIndexMap);
// Add sections to the groups
for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
it != ie; ++it) {
const MCSectionELF &Section =
static_cast<const MCSectionELF&>(it->getSection());
if (!(Section.getFlags() & ELF::SHF_GROUP))
continue;
const MCSectionELF *Group = RevGroupMap[Section.getGroup()];
MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
// FIXME: we could use the previous fragment
MCDataFragment *F = new MCDataFragment(&Data);
uint32_t Index = SectionIndexMap.lookup(&Section);
write(*F, Index);
}
computeIndexMap(Asm, Sections, SectionIndexMap, RevGroupMap);
}
void ELFObjectWriter::writeSection(MCAssembler &Asm,
@ -1572,19 +1587,15 @@ void ELFObjectWriter::WriteObject(MCAssembler &Asm,
SectionIndexMapTy SectionIndexMap;
CompressDebugSections(Asm, const_cast<MCAsmLayout &>(Layout));
std::vector<const MCSectionELF *> Sections;
createIndexedSections(Asm, const_cast<MCAsmLayout &>(Layout), RevGroupMap,
SectionIndexMap);
Sections, SectionIndexMap);
// Compute symbol table information.
computeSymbolTable(Asm, Layout, SectionIndexMap, RevGroupMap);
WriteRelocations(Asm, const_cast<MCAsmLayout &>(Layout));
std::vector<const MCSectionELF*> Sections;
Sections.resize(SectionIndexMap.size());
for (auto &Pair : SectionIndexMap)
Sections[Pair.second - 1] = Pair.first;
CreateMetadataSections(const_cast<MCAssembler &>(Asm),
const_cast<MCAsmLayout &>(Layout), Sections);