Initial comdat implementation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118805 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index 93ea77a..f8caee9 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -326,6 +326,11 @@
void CreateMetadataSections(MCAssembler &Asm, MCAsmLayout &Layout,
const SectionIndexMapTy &SectionIndexMap);
+ // Map from a group section to the signature symbol
+ typedef DenseMap<const MCSectionELF*, const MCSymbol*> GroupMapTy;
+ void CreateGroupSections(MCAssembler &Asm, MCAsmLayout &Layout,
+ GroupMapTy &GroupMap);
+
void ExecutePostLayoutBinding(MCAssembler &Asm);
void WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags,
@@ -344,6 +349,7 @@
void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout);
void WriteSection(MCAssembler &Asm,
const SectionIndexMapTy &SectionIndexMap,
+ uint32_t GroupSymbolIndex,
uint64_t Offset, uint64_t Size, uint64_t Alignment,
const MCSectionELF &Section);
};
@@ -939,6 +945,17 @@
ie = Asm.end(); it != ie; ++it) {
const MCSectionELF &Section =
static_cast<const MCSectionELF &>(it->getSection());
+ if (Section.getType() != ELF::SHT_GROUP)
+ continue;
+ SectionIndexMap[&Section] = Index++;
+ }
+
+ for (MCAssembler::iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it) {
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF &>(it->getSection());
+ if (Section.getType() == ELF::SHT_GROUP)
+ continue;
SectionIndexMap[&Section] = Index++;
}
}
@@ -1062,7 +1079,7 @@
RelaSection = Ctx.getELFSection(RelaSectionName, HasRelocationAddend ?
ELF::SHT_RELA : ELF::SHT_REL, 0,
SectionKind::getReadOnly(),
- EntrySize);
+ EntrySize, "");
MCSectionData &RelaSD = Asm.getOrCreateSectionData(*RelaSection);
RelaSD.setAlignment(Is64Bit ? 8 : 4);
@@ -1148,7 +1165,7 @@
const MCSectionELF *SymtabSection =
Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0,
SectionKind::getReadOnly(),
- EntrySize);
+ EntrySize, "");
MCSectionData &SymtabSD = Asm.getOrCreateSectionData(*SymtabSection);
SymtabSD.setAlignment(Is64Bit ? 8 : 4);
SymbolTableIndex = Asm.size();
@@ -1158,7 +1175,7 @@
if (NeedsSymtabShndx) {
const MCSectionELF *SymtabShndxSection =
Ctx.getELFSection(".symtab_shndx", ELF::SHT_SYMTAB_SHNDX, 0,
- SectionKind::getReadOnly(), 4);
+ SectionKind::getReadOnly(), 4, "");
SymtabShndxSD = &Asm.getOrCreateSectionData(*SymtabShndxSection);
SymtabShndxSD->setAlignment(4);
}
@@ -1195,18 +1212,25 @@
uint64_t Index = 1;
F->getContents() += '\x00';
+ StringMap<uint64_t> SecStringMap;
for (MCAssembler::const_iterator it = Asm.begin(),
ie = Asm.end(); it != ie; ++it) {
const MCSectionELF &Section =
static_cast<const MCSectionELF&>(it->getSection());
// FIXME: We could merge suffixes like in .text and .rela.text.
+ StringRef Name = Section.getSectionName();
+ if (SecStringMap.count(Name)) {
+ SectionStringTableIndex[&Section] = SecStringMap[Name];
+ continue;
+ }
// Remember the index into the string table so we can write it
// into the sh_name field of the section header table.
- SectionStringTableIndex[&it->getSection()] = Index;
+ SectionStringTableIndex[&Section] = Index;
+ SecStringMap[Name] = Index;
- Index += Section.getSectionName().size() + 1;
- F->getContents() += Section.getSectionName();
+ Index += Name.size() + 1;
+ F->getContents() += Name;
F->getContents() += '\x00';
}
@@ -1247,8 +1271,59 @@
return !SectionB && BaseSection == SectionA;
}
+void ELFObjectWriterImpl::CreateGroupSections(MCAssembler &Asm,
+ MCAsmLayout &Layout,
+ GroupMapTy &GroupMap) {
+ typedef DenseMap<const MCSymbol*, const MCSectionELF*> RevGroupMapTy;
+ // Build the groups
+ RevGroupMapTy 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() & MCSectionELF::SHF_GROUP))
+ continue;
+
+ const MCSymbol *SignatureSymbol = Section.getGroup();
+ Asm.getOrCreateSymbolData(*SignatureSymbol);
+ const MCSectionELF *&Group = Groups[SignatureSymbol];
+ if (!Group) {
+ Group = Asm.getContext().CreateELFGroupSection();
+ MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
+ Data.setAlignment(4);
+ MCDataFragment *F = new MCDataFragment(&Data);
+ String32(*F, ELF::GRP_COMDAT);
+ }
+ GroupMap[Group] = SignatureSymbol;
+ }
+
+ // Add sections to the groups
+ unsigned Index = 1;
+ unsigned NumGroups = Groups.size();
+ for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
+ it != ie; ++it, ++Index) {
+ const MCSectionELF &Section =
+ static_cast<const MCSectionELF&>(it->getSection());
+ if (!(Section.getFlags() & MCSectionELF::SHF_GROUP))
+ continue;
+ const MCSectionELF *Group = Groups[Section.getGroup()];
+ MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
+ // FIXME: we could use the previous fragment
+ MCDataFragment *F = new MCDataFragment(&Data);
+ String32(*F, NumGroups + Index);
+ }
+
+ for (RevGroupMapTy::const_iterator i = Groups.begin(), e = Groups.end();
+ i != e; ++i) {
+ const MCSectionELF *Group = i->second;
+ MCSectionData &Data = Asm.getOrCreateSectionData(*Group);
+ Asm.AddSectionToTheEnd(*Writer, Data, Layout);
+ }
+}
+
void ELFObjectWriterImpl::WriteSection(MCAssembler &Asm,
const SectionIndexMapTy &SectionIndexMap,
+ uint32_t GroupSymbolIndex,
uint64_t Offset, uint64_t Size,
uint64_t Alignment,
const MCSectionELF &Section) {
@@ -1300,6 +1375,12 @@
// Nothing to do.
break;
+ case ELF::SHT_GROUP: {
+ sh_link = SymbolTableIndex;
+ sh_info = GroupSymbolIndex;
+ break;
+ }
+
default:
assert(0 && "FIXME: sh_type value not supported!");
break;
@@ -1312,6 +1393,10 @@
void ELFObjectWriterImpl::WriteObject(MCAssembler &Asm,
const MCAsmLayout &Layout) {
+
+ GroupMapTy GroupMap;
+ CreateGroupSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap);
+
SectionIndexMapTy SectionIndexMap;
ComputeIndexMap(Asm, SectionIndexMap);
@@ -1332,9 +1417,18 @@
uint64_t HeaderSize = Is64Bit ? sizeof(ELF::Elf64_Ehdr) : sizeof(ELF::Elf32_Ehdr);
uint64_t FileOff = HeaderSize;
- for (MCAssembler::const_iterator it = Asm.begin(),
- ie = Asm.end(); it != ie; ++it) {
- const MCSectionData &SD = *it;
+ std::vector<const MCSectionELF*> Sections;
+ Sections.resize(NumSections);
+
+ for (SectionIndexMapTy::const_iterator i=
+ SectionIndexMap.begin(), e = SectionIndexMap.end(); i != e; ++i) {
+ const std::pair<const MCSectionELF*, uint32_t> &p = *i;
+ Sections[p.second] = p.first;
+ }
+
+ for (unsigned i = 1; i < NumSections; ++i) {
+ const MCSectionELF &Section = *Sections[i];
+ const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
FileOff = RoundUpToAlignment(FileOff, SD.getAlignment());
@@ -1354,20 +1448,20 @@
// ... then all of the sections ...
DenseMap<const MCSection*, uint64_t> SectionOffsetMap;
- for (MCAssembler::const_iterator it = Asm.begin(),
- ie = Asm.end(); it != ie; ++it) {
- const MCSectionData &SD = *it;
+ for (unsigned i = 1; i < NumSections; ++i) {
+ const MCSectionELF &Section = *Sections[i];
+ const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
uint64_t Padding = OffsetToAlignment(FileOff, SD.getAlignment());
WriteZeros(Padding);
FileOff += Padding;
// Remember the offset into the file for this section.
- SectionOffsetMap[&it->getSection()] = FileOff;
+ SectionOffsetMap[&Section] = FileOff;
FileOff += Layout.getSectionFileSize(&SD);
- Asm.WriteSectionData(it, Layout, Writer);
+ Asm.WriteSectionData(&SD, Layout, Writer);
}
uint64_t Padding = OffsetToAlignment(FileOff, NaturalAlignment);
@@ -1384,14 +1478,17 @@
ShstrtabIndex >= ELF::SHN_LORESERVE ? ShstrtabIndex : 0;
WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, FirstSectionLink, 0, 0, 0);
- for (MCAssembler::const_iterator it = Asm.begin(),
- ie = Asm.end(); it != ie; ++it) {
- const MCSectionData &SD = *it;
- const MCSectionELF &Section =
- static_cast<const MCSectionELF&>(SD.getSection());
+ for (unsigned i = 1; i < NumSections; ++i) {
+ const MCSectionELF &Section = *Sections[i];
+ const MCSectionData &SD = Asm.getOrCreateSectionData(Section);
+ uint32_t GroupSymbolIndex;
+ if (Section.getType() != ELF::SHT_GROUP)
+ GroupSymbolIndex = 0;
+ else
+ GroupSymbolIndex = getSymbolIndexInSymbolTable(Asm, GroupMap[&Section]);
- WriteSection(Asm, SectionIndexMap, SectionOffsetMap[&Section],
- Layout.getSectionSize(&SD),
+ WriteSection(Asm, SectionIndexMap, GroupSymbolIndex,
+ SectionOffsetMap[&Section], Layout.getSectionSize(&SD),
SD.getAlignment(), Section);
}
}
diff --git a/lib/MC/MCContext.cpp b/lib/MC/MCContext.cpp
index bafa10a..311f383 100644
--- a/lib/MC/MCContext.cpp
+++ b/lib/MC/MCContext.cpp
@@ -150,7 +150,13 @@
const MCSectionELF *MCContext::
getELFSection(StringRef Section, unsigned Type, unsigned Flags,
- SectionKind Kind, unsigned EntrySize) {
+ SectionKind Kind) {
+ return getELFSection(Section, Type, Flags, Kind, 0, "");
+}
+
+const MCSectionELF *MCContext::
+getELFSection(StringRef Section, unsigned Type, unsigned Flags,
+ SectionKind Kind, unsigned EntrySize, StringRef Group) {
if (ELFUniquingMap == 0)
ELFUniquingMap = new ELFUniqueMapTy();
ELFUniqueMapTy &Map = *(ELFUniqueMapTy*)ELFUniquingMap;
@@ -163,12 +169,24 @@
if (!EntrySize) {
EntrySize = MCSectionELF::DetermineEntrySize(Kind);
}
+
+ MCSymbol *GroupSym = NULL;
+ if (!Group.empty())
+ GroupSym = GetOrCreateSymbol(Group);
+
MCSectionELF *Result = new (*this) MCSectionELF(Entry.getKey(), Type, Flags,
- Kind, EntrySize);
+ Kind, EntrySize, GroupSym);
Entry.setValue(Result);
return Result;
}
+const MCSectionELF *MCContext::CreateELFGroupSection() {
+ MCSectionELF *Result =
+ new (*this) MCSectionELF(".group", MCSectionELF::SHT_GROUP, 0,
+ SectionKind::getReadOnly(), 4, NULL);
+ return Result;
+}
+
const MCSection *MCContext::getCOFFSection(StringRef Section,
unsigned Characteristics,
int Selection,
diff --git a/lib/MC/MCParser/ELFAsmParser.cpp b/lib/MC/MCParser/ELFAsmParser.cpp
index 75eee3d..278f146 100644
--- a/lib/MC/MCParser/ELFAsmParser.cpp
+++ b/lib/MC/MCParser/ELFAsmParser.cpp
@@ -203,6 +203,7 @@
StringRef FlagsStr;
StringRef TypeName;
int64_t Size = 0;
+ StringRef GroupName;
if (getLexer().is(AsmToken::Comma)) {
Lex();
@@ -249,7 +250,6 @@
if (getLexer().isNot(AsmToken::Comma))
return TokError("expected group name");
Lex();
- StringRef GroupName;
if (getParser().ParseIdentifier(GroupName))
return true;
if (getLexer().is(AsmToken::Comma)) {
@@ -257,8 +257,8 @@
StringRef Linkage;
if (getParser().ParseIdentifier(Linkage))
return true;
- if (Linkage != "comdat" && Linkage != ".gnu.linkonce")
- return TokError("Linkage must be 'comdat' or '.gnu.linkonce'");
+ if (Linkage != "comdat")
+ return TokError("Linkage must be 'comdat'");
}
}
}
@@ -306,6 +306,7 @@
Flags |= MCSectionELF::XCORE_SHF_DP_SECTION;
break;
case 'G':
+ Flags |= MCSectionELF::SHF_GROUP;
break;
default:
return TokError("unknown flag");
@@ -331,7 +332,8 @@
? SectionKind::getText()
: SectionKind::getDataRel();
getStreamer().SwitchSection(getContext().getELFSection(SectionName, Type,
- Flags, Kind, Size));
+ Flags, Kind, Size,
+ GroupName));
return false;
}
@@ -405,7 +407,7 @@
MCSectionELF::SHF_MERGE |
MCSectionELF::SHF_STRINGS,
SectionKind::getReadOnly(),
- 1);
+ 1, "");
static bool First = true;