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Initial comdat implementation.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118805 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Rafael Espindola 2010-11-11 18:13:52 +00:00
parent 56653f0df8
commit 2ff9e83a82
8 changed files with 213 additions and 38 deletions
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7
include/llvm/MC/MCContext.h
View File

@ -139,9 +139,14 @@ namespace llvm {
return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
}
const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
unsigned Flags, SectionKind Kind);
const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
unsigned Flags, SectionKind Kind,
unsigned EntrySize = 0);
unsigned EntrySize, StringRef Group);
const MCSectionELF *CreateELFGroupSection();
const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
int Selection, SectionKind Kind);

9
include/llvm/MC/MCSectionELF.h
View File

@ -18,6 +18,8 @@
namespace llvm {
class MCSymbol;
/// MCSectionELF - This represents a section on linux, lots of unix variants
/// and some bare metal systems.
class MCSectionELF : public MCSection {
@ -37,12 +39,14 @@ class MCSectionELF : public MCSection {
/// section does not contain fixed-sized entries 'EntrySize' will be 0.
unsigned EntrySize;
const MCSymbol *Group;
private:
friend class MCContext;
MCSectionELF(StringRef Section, unsigned type, unsigned flags,
SectionKind K, unsigned entrySize)
SectionKind K, unsigned entrySize, const MCSymbol *group)
: MCSection(SV_ELF, K), SectionName(Section), Type(type), Flags(flags),
EntrySize(entrySize) {}
EntrySize(entrySize), Group(group) {}
~MCSectionELF();
public:
@ -179,6 +183,7 @@ public:
unsigned getType() const { return Type; }
unsigned getFlags() const { return Flags; }
unsigned getEntrySize() const { return EntrySize; }
const MCSymbol *getGroup() const { return Group; }
void PrintSwitchToSection(const MCAsmInfo &MAI,
raw_ostream &OS) const;

7
include/llvm/Support/ELF.h
View File

@ -348,6 +348,13 @@ enum {
SHF_MASKPROC = 0xf0000000 // Bits indicating processor-specific flags.
};
// Section Group Flags
enum {
GRP_COMDAT = 0x1,
GRP_MASKOS = 0x0ff00000,
GRP_MASKPROC = 0xf0000000
};
// Symbol table entries for ELF32.
struct Elf32_Sym {
Elf32_Word st_name; // Symbol name (index into string table)

139
lib/MC/ELFObjectWriter.cpp
View File

@ -326,6 +326,11 @@ namespace {
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 @@ namespace {
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 @@ void ELFObjectWriterImpl::ComputeIndexMap(MCAssembler &Asm,
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 @@ void ELFObjectWriterImpl::WriteRelocation(MCAssembler &Asm, MCAsmLayout &Layout,
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 @@ void ELFObjectWriterImpl::CreateMetadataSections(MCAssembler &Asm,
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 @@ void ELFObjectWriterImpl::CreateMetadataSections(MCAssembler &Asm,
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 @@ void ELFObjectWriterImpl::CreateMetadataSections(MCAssembler &Asm,
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 @@ bool ELFObjectWriterImpl::IsFixupFullyResolved(const MCAssembler &Asm,
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 @@ void ELFObjectWriterImpl::WriteSection(MCAssembler &Asm,
// 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::WriteSection(MCAssembler &Asm,
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 @@ void ELFObjectWriterImpl::WriteObject(MCAssembler &Asm,
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 @@ void ELFObjectWriterImpl::WriteObject(MCAssembler &Asm,
// ... 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 @@ void ELFObjectWriterImpl::WriteObject(MCAssembler &Asm,
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);
}
}

22
lib/MC/MCContext.cpp
View File

@ -150,7 +150,13 @@ getMachOSection(StringRef Segment, StringRef Section,
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 @@ getELFSection(StringRef Section, unsigned Type, unsigned Flags,
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,

12
lib/MC/MCParser/ELFAsmParser.cpp
View File

@ -203,6 +203,7 @@ bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
StringRef FlagsStr;
StringRef TypeName;
int64_t Size = 0;
StringRef GroupName;
if (getLexer().is(AsmToken::Comma)) {
Lex();
@ -249,7 +250,6 @@ bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
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 @@ bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
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 @@ bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
Flags |= MCSectionELF::XCORE_SHF_DP_SECTION;
break;
case 'G':
Flags |= MCSectionELF::SHF_GROUP;
break;
default:
return TokError("unknown flag");
@ -331,7 +332,8 @@ bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
? SectionKind::getText()
: SectionKind::getDataRel();
getStreamer().SwitchSection(getContext().getELFSection(SectionName, Type,
Flags, Kind, Size));
Flags, Kind, Size,
GroupName));
return false;
}
@ -405,7 +407,7 @@ bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
MCSectionELF::SHF_MERGE |
MCSectionELF::SHF_STRINGS,
SectionKind::getReadOnly(),
1);
1, "");
static bool First = true;

39
test/MC/ELF/comdat.s Normal file
View File

@ -0,0 +1,39 @@
// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | elf-dump | FileCheck %s
// Test that we produce the two group sections and that they are a the beginning
// of the file.
// CHECK: # Section 0x00000001
// CHECK-NEXT: (('sh_name', 0x00000021) # '.group'
// CHECK-NEXT: ('sh_type', 0x00000011)
// CHECK-NEXT: ('sh_flags', 0x00000000)
// CHECK-NEXT: ('sh_addr', 0x00000000)
// CHECK-NEXT: ('sh_offset', 0x00000040)
// CHECK-NEXT: ('sh_size', 0x0000000c)
// CHECK-NEXT: ('sh_link', 0x0000000a)
// CHECK-NEXT: ('sh_info', 0x00000001)
// CHECK-NEXT: ('sh_addralign', 0x00000004)
// CHECK-NEXT: ('sh_entsize', 0x00000004)
// CHECK-NEXT: ),
// CHECK-NEXT: # Section 0x00000002
// CHECK-NEXT: (('sh_name', 0x00000021) # '.group'
// CHECK-NEXT: ('sh_type', 0x00000011)
// CHECK-NEXT: ('sh_flags', 0x00000000)
// CHECK-NEXT: ('sh_addr', 0x00000000)
// CHECK-NEXT: ('sh_offset', 0x0000004c)
// CHECK-NEXT: ('sh_size', 0x00000008)
// CHECK-NEXT: ('sh_link', 0x0000000a)
// CHECK-NEXT: ('sh_info', 0x00000002)
// CHECK-NEXT: ('sh_addralign', 0x00000004)
// CHECK-NEXT: ('sh_entsize', 0x00000004)
.section .foo,"axG",@progbits,g1,comdat
g1:
nop
.section .bar,"axG",@progbits,g1,comdat
nop
.section .zed,"axG",@progbits,g2,comdat
g2:
nop

14
test/MC/ELF/section.s
View File

@ -20,31 +20,31 @@
// CHECK-NEXT: ('sh_type', 0x00000001)
// CHECK-NEXT: ('sh_flags', 0x00000006)
// CHECK-NEXT: ('sh_addr', 0x00000000)
// CHECK-NEXT: ('sh_offset', 0x00000040)
// CHECK-NEXT: ('sh_offset', 0x00000050)
// CHECK-NEXT: ('sh_size', 0x00000000)
// CHECK-NEXT: ('sh_link', 0x00000000)
// CHECK-NEXT: ('sh_info', 0x00000000)
// CHECK-NEXT: ('sh_addralign', 0x00000001)
// CHECK-NEXT: ('sh_entsize', 0x00000000)
// CHECK-NEXT: ),
// CHECK-NEXT: # Section 0x00000008
// CHECK-NEXT: # Section 0x0000000a
// CHECK-NEXT: (('sh_name', 0x0000003e) # '.fini'
// CHECK-NEXT: ('sh_type', 0x00000001)
// CHECK-NEXT: ('sh_flags', 0x00000006)
// CHECK-NEXT: ('sh_addr', 0x00000000)
// CHECK-NEXT: ('sh_offset', 0x00000040)
// CHECK-NEXT: ('sh_offset', 0x00000050)
// CHECK-NEXT: ('sh_size', 0x00000000)
// CHECK-NEXT: ('sh_link', 0x00000000)
// CHECK-NEXT: ('sh_info', 0x00000000)
// CHECK-NEXT: ('sh_addralign', 0x00000001)
// CHECK-NEXT: ('sh_entsize', 0x00000000)
// CHECK-NEXT: ),
// CHECK-NEXT: # Section 0x00000009
// CHECK-NEXT: # Section 0x0000000b
// CHECK-NEXT: (('sh_name', 0x00000044) # '.rodata'
// CHECK-NEXT: ('sh_type', 0x00000001)
// CHECK-NEXT: ('sh_flags', 0x00000002)
// CHECK-NEXT: ('sh_addr', 0x00000000)
// CHECK-NEXT: ('sh_offset', 0x00000040)
// CHECK-NEXT: ('sh_offset', 0x00000050)
// CHECK-NEXT: ('sh_size', 0x00000000)
// CHECK-NEXT: ('sh_link', 0x00000000)
// CHECK-NEXT: ('sh_info', 0x00000000)
@ -53,5 +53,7 @@
// CHECK-NEXT: ),
// Test that we can parse these
foo:
bar:
.section .text.foo,"axG",@progbits,foo,comdat
.section .text.bar,"axMG",@progbits,42,bar,.gnu.linkonce
.section .text.bar,"axMG",@progbits,42,bar,comdat