[lld] Explicitly ignore comdat groups when parsing LTO object(s)
Any symbols defined in the LTO object are by definition the ones we
want in the final output so we skip the comdat group checking in those
cases.
This change makes the ELF code more explicit about this and means
that wasm and ELF do this in the same way.
Differential Revision: https://reviews.llvm.org/D62884
git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@362625 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/ELF/Driver.cpp b/ELF/Driver.cpp
index a90522a..9a7b762 100644
--- a/ELF/Driver.cpp
+++ b/ELF/Driver.cpp
@@ -1506,9 +1506,8 @@
LTO->add(*File);
for (InputFile *File : LTO->compile()) {
- DenseMap<CachedHashStringRef, const InputFile *> DummyGroups;
auto *Obj = cast<ObjFile<ELFT>>(File);
- Obj->parse(DummyGroups);
+ Obj->parse(/*IgnoreComdats=*/true);
for (Symbol *Sym : Obj->getGlobalSymbols())
Sym->parseSymbolVersion();
ObjectFiles.push_back(File);
diff --git a/ELF/InputFiles.cpp b/ELF/InputFiles.cpp
index a863894..dd38478 100644
--- a/ELF/InputFiles.cpp
+++ b/ELF/InputFiles.cpp
@@ -178,13 +178,13 @@
// LLVM bitcode file
if (auto *F = dyn_cast<BitcodeFile>(File)) {
BitcodeFiles.push_back(F);
- F->parse<ELFT>(Symtab->ComdatGroups);
+ F->parse<ELFT>();
return;
}
// Regular object file
ObjectFiles.push_back(File);
- cast<ObjFile<ELFT>>(File)->parse(Symtab->ComdatGroups);
+ cast<ObjFile<ELFT>>(File)->parse();
}
// Add symbols in File to the symbol table.
@@ -449,14 +449,12 @@
return makeArrayRef(this->Symbols).slice(this->FirstGlobal);
}
-template <class ELFT>
-void ObjFile<ELFT>::parse(
- DenseMap<CachedHashStringRef, const InputFile *> &ComdatGroups) {
+template <class ELFT> void ObjFile<ELFT>::parse(bool IgnoreComdats) {
// Read a section table. JustSymbols is usually false.
if (this->JustSymbols)
initializeJustSymbols();
else
- initializeSections(ComdatGroups);
+ initializeSections(IgnoreComdats);
// Read a symbol table.
initializeSymbols();
@@ -564,8 +562,7 @@
}
template <class ELFT>
-void ObjFile<ELFT>::initializeSections(
- DenseMap<CachedHashStringRef, const InputFile *> &ComdatGroups) {
+void ObjFile<ELFT>::initializeSections(bool IgnoreComdats) {
const ELFFile<ELFT> &Obj = this->getObj();
ArrayRef<Elf_Shdr> ObjSections = CHECK(Obj.sections(), this);
@@ -625,7 +622,9 @@
fatal(toString(this) + ": unsupported SHT_GROUP format");
bool IsNew =
- ComdatGroups.try_emplace(CachedHashStringRef(Signature), this).second;
+ IgnoreComdats ||
+ Symtab->ComdatGroups.try_emplace(CachedHashStringRef(Signature), this)
+ .second;
if (IsNew) {
if (Config->Relocatable)
this->Sections[I] = createInputSection(Sec);
@@ -1478,13 +1477,11 @@
return Symtab->addSymbol(New);
}
-template <class ELFT>
-void BitcodeFile::parse(
- DenseMap<CachedHashStringRef, const InputFile *> &ComdatGroups) {
+template <class ELFT> void BitcodeFile::parse() {
std::vector<bool> KeptComdats;
for (StringRef S : Obj->getComdatTable())
KeptComdats.push_back(
- ComdatGroups.try_emplace(CachedHashStringRef(S), this).second);
+ Symtab->ComdatGroups.try_emplace(CachedHashStringRef(S), this).second);
for (const lto::InputFile::Symbol &ObjSym : Obj->symbols())
Symbols.push_back(createBitcodeSymbol<ELFT>(KeptComdats, ObjSym, *this));
@@ -1617,14 +1614,10 @@
return Path;
}
-template void
-BitcodeFile::parse<ELF32LE>(DenseMap<CachedHashStringRef, const InputFile *> &);
-template void
-BitcodeFile::parse<ELF32BE>(DenseMap<CachedHashStringRef, const InputFile *> &);
-template void
-BitcodeFile::parse<ELF64LE>(DenseMap<CachedHashStringRef, const InputFile *> &);
-template void
-BitcodeFile::parse<ELF64BE>(DenseMap<CachedHashStringRef, const InputFile *> &);
+template void BitcodeFile::parse<ELF32LE>();
+template void BitcodeFile::parse<ELF32BE>();
+template void BitcodeFile::parse<ELF64LE>();
+template void BitcodeFile::parse<ELF64BE>();
template void LazyObjFile::parse<ELF32LE>();
template void LazyObjFile::parse<ELF32BE>();
diff --git a/ELF/InputFiles.h b/ELF/InputFiles.h
index 64cd020..98f2e81 100644
--- a/ELF/InputFiles.h
+++ b/ELF/InputFiles.h
@@ -201,8 +201,7 @@
this->ArchiveName = ArchiveName;
}
- void parse(llvm::DenseMap<llvm::CachedHashStringRef, const InputFile *>
- &ComdatGroups);
+ void parse(bool IgnoreComdats = false);
StringRef getShtGroupSignature(ArrayRef<Elf_Shdr> Sections,
const Elf_Shdr &Sec);
@@ -250,8 +249,7 @@
ArrayRef<Elf_CGProfile> CGProfile;
private:
- void initializeSections(llvm::DenseMap<llvm::CachedHashStringRef,
- const InputFile *> &ComdatGroups);
+ void initializeSections(bool IgnoreComdats);
void initializeSymbols();
void initializeJustSymbols();
void initializeDwarf();
@@ -340,9 +338,7 @@
BitcodeFile(MemoryBufferRef M, StringRef ArchiveName,
uint64_t OffsetInArchive);
static bool classof(const InputFile *F) { return F->kind() == BitcodeKind; }
- template <class ELFT>
- void parse(llvm::DenseMap<llvm::CachedHashStringRef, const InputFile *>
- &ComdatGroups);
+ template <class ELFT> void parse();
std::unique_ptr<llvm::lto::InputFile> Obj;
};
diff --git a/wasm/InputFiles.cpp b/wasm/InputFiles.cpp
index e1c4fa7..23d3900 100644
--- a/wasm/InputFiles.cpp
+++ b/wasm/InputFiles.cpp
@@ -306,11 +306,10 @@
TypeIsUsed.resize(getWasmObj()->types().size(), false);
ArrayRef<StringRef> Comdats = WasmObj->linkingData().Comdats;
- for (unsigned I = 0; I < Comdats.size(); ++I)
- if (IgnoreComdats)
- KeptComdats.push_back(true);
- else
- KeptComdats.push_back(Symtab->addComdat(Comdats[I]));
+ for (unsigned I = 0; I < Comdats.size(); ++I) {
+ bool IsNew = IgnoreComdats || Symtab->addComdat(Comdats[I]);
+ KeptComdats.push_back(IsNew);
+ }
// Populate `Segments`.
for (const WasmSegment &S : WasmObj->dataSegments())
@@ -535,10 +534,7 @@
}
std::vector<bool> KeptComdats;
for (StringRef S : Obj->getComdatTable())
- if (IgnoreComdats)
- KeptComdats.push_back(true);
- else
- KeptComdats.push_back(Symtab->addComdat(S));
+ KeptComdats.push_back(Symtab->addComdat(S));
for (const lto::InputFile::Symbol &ObjSym : Obj->symbols())
Symbols.push_back(createBitcodeSymbol(KeptComdats, ObjSym, *this));
