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[LTO] Fix the logic for dropping unnamed_addr. 

Differential Revision:  https://reviews.llvm.org/D24037

llvm-svn: 280144
This commit is contained in:
Davide Italiano 2016-08-30 20:15:03 +00:00
parent c943d72d94
commit 35af5b3d21
8 changed files with 75 additions and 31 deletions
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27
lld/ELF/InputFiles.cpp
View File

@ -382,12 +382,13 @@ SymbolBody *elf::ObjectFile<ELFT>::createSymbolBody(const Elf_Sym *Sym) {
case SHN_UNDEF:
return elf::Symtab<ELFT>::X
->addUndefined(Name, Binding, Sym->st_other, Sym->getType(),
/*CanOmitFromDynSym*/ false, this)
/*CanOmitFromDynSym*/ false, /*HasUnnamedAddr*/ false,
this)
->body();
case SHN_COMMON:
return elf::Symtab<ELFT>::X
->addCommon(Name, Sym->st_size, Sym->st_value, Binding, Sym->st_other,
Sym->getType(), this)
Sym->getType(), /*HasUnnamedAddr*/ false, this)
->body();
}
@ -400,7 +401,8 @@ SymbolBody *elf::ObjectFile<ELFT>::createSymbolBody(const Elf_Sym *Sym) {
if (Sec == &InputSection<ELFT>::Discarded)
return elf::Symtab<ELFT>::X
->addUndefined(Name, Binding, Sym->st_other, Sym->getType(),
/*CanOmitFromDynSym*/ false, this)
/*CanOmitFromDynSym*/ false,
/*HasUnnamedAddr*/ false, this)
->body();
return elf::Symtab<ELFT>::X->addRegular(Name, *Sym, Sec)->body();
}
@ -646,23 +648,29 @@ Symbol *BitcodeFile::createSymbol(const DenseSet<const Comdat *> &KeptComdats,
}
uint8_t Visibility;
if (GV)
bool HasUnnamedAddr = false;
if (GV) {
Visibility = getGvVisibility(GV);
else
HasUnnamedAddr =
GV->getUnnamedAddr() == llvm::GlobalValue::UnnamedAddr::Global;
} else {
// FIXME: Set SF_Hidden flag correctly for module asm symbols, and expose
// protected visibility.
Visibility = STV_DEFAULT;
}
if (GV)
if (const Comdat *C = GV->getComdat())
if (!KeptComdats.count(C))
return Symtab<ELFT>::X->addUndefined(NameRef, Binding, Visibility, Type,
CanOmitFromDynSym, this);
CanOmitFromDynSym, HasUnnamedAddr,
this);
const Module &M = Obj.getModule();
if (Flags & BasicSymbolRef::SF_Undefined)
return Symtab<ELFT>::X->addUndefined(NameRef, Binding, Visibility, Type,
CanOmitFromDynSym, this);
CanOmitFromDynSym, HasUnnamedAddr,
this);
if (Flags & BasicSymbolRef::SF_Common) {
// FIXME: Set SF_Common flag correctly for module asm symbols, and expose
// size and alignment.
@ -670,10 +678,11 @@ Symbol *BitcodeFile::createSymbol(const DenseSet<const Comdat *> &KeptComdats,
const DataLayout &DL = M.getDataLayout();
uint64_t Size = DL.getTypeAllocSize(GV->getValueType());
return Symtab<ELFT>::X->addCommon(NameRef, Size, GV->getAlignment(),
Binding, Visibility, STT_OBJECT, this);
Binding, Visibility, STT_OBJECT,
HasUnnamedAddr, this);
}
return Symtab<ELFT>::X->addBitcode(NameRef, IsWeak, Visibility, Type,
CanOmitFromDynSym, this);
CanOmitFromDynSym, HasUnnamedAddr, this);
}
bool BitcodeFile::shouldSkip(uint32_t Flags) {

6
lld/ELF/LTO.cpp
View File

@ -194,6 +194,12 @@ void BitcodeCompiler::add(BitcodeFile &F) {
if (BitcodeFile::shouldSkip(Flags))
continue;
Symbol *S = Syms[BodyIndex++];
if (GV) {
if (S->HasUnnamedAddr)
GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
else
GV->setUnnamedAddr(GlobalValue::UnnamedAddr::None);
}
if (Flags & BasicSymbolRef::SF_Undefined) {
handleUndefinedAsmRefs(Sym, GV, AsmUndefinedRefs);
continue;

39
lld/ELF/SymbolTable.cpp
View File

@ -219,6 +219,7 @@ std::pair<Symbol *, bool> SymbolTable<ELFT>::insert(StringRef &Name) {
Sym->Binding = STB_WEAK;
Sym->Visibility = STV_DEFAULT;
Sym->IsUsedInRegularObj = false;
Sym->HasUnnamedAddr = true;
Sym->ExportDynamic = false;
Sym->Traced = V.Traced;
std::tie(Name, Sym->VersionId) = getSymbolVersion(Name);
@ -234,12 +235,14 @@ std::pair<Symbol *, bool> SymbolTable<ELFT>::insert(StringRef &Name) {
template <class ELFT>
std::pair<Symbol *, bool>
SymbolTable<ELFT>::insert(StringRef &Name, uint8_t Type, uint8_t Visibility,
bool CanOmitFromDynSym, bool IsUsedInRegularObj,
InputFile *File) {
bool CanOmitFromDynSym, bool HasUnnamedAddr,
bool IsUsedInRegularObj, InputFile *File) {
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) = insert(Name);
// Merge in the new unnamed_addr attribute.
S->HasUnnamedAddr &= HasUnnamedAddr;
// Merge in the new symbol's visibility.
S->Visibility = getMinVisibility(S->Visibility, Visibility);
if (!CanOmitFromDynSym && (Config->Shared || Config->ExportDynamic))
@ -268,18 +271,19 @@ std::string SymbolTable<ELFT>::conflictMsg(SymbolBody *Existing,
template <class ELFT> Symbol *SymbolTable<ELFT>::addUndefined(StringRef Name) {
return addUndefined(Name, STB_GLOBAL, STV_DEFAULT, /*Type*/ 0,
/*CanOmitFromDynSym*/ false, /*File*/ nullptr);
/*CanOmitFromDynSym*/ false, /*HasUnnamedAddr*/ false,
/*File*/ nullptr);
}
template <class ELFT>
Symbol *SymbolTable<ELFT>::addUndefined(StringRef Name, uint8_t Binding,
uint8_t StOther, uint8_t Type,
bool CanOmitFromDynSym,
InputFile *File) {
bool HasUnnamedAddr, InputFile *File) {
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) =
insert(Name, Type, StOther & 3, CanOmitFromDynSym,
insert(Name, Type, StOther & 3, CanOmitFromDynSym, HasUnnamedAddr,
/*IsUsedInRegularObj*/ !File || !isa<BitcodeFile>(File), File);
if (WasInserted) {
S->Binding = Binding;
@ -343,11 +347,11 @@ template <class ELFT>
Symbol *SymbolTable<ELFT>::addCommon(StringRef N, uint64_t Size,
uint64_t Alignment, uint8_t Binding,
uint8_t StOther, uint8_t Type,
InputFile *File) {
bool HasUnnamedAddr, InputFile *File) {
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) =
insert(N, Type, StOther & 3, /*CanOmitFromDynSym*/ false,
insert(N, Type, StOther & 3, /*CanOmitFromDynSym*/ false, HasUnnamedAddr,
/*IsUsedInRegularObj*/ true, File);
int Cmp = compareDefined(S, WasInserted, Binding);
if (Cmp > 0) {
@ -387,10 +391,10 @@ Symbol *SymbolTable<ELFT>::addRegular(StringRef Name, const Elf_Sym &Sym,
InputSectionBase<ELFT> *Section) {
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) =
insert(Name, Sym.getType(), Sym.getVisibility(),
/*CanOmitFromDynSym*/ false, /*IsUsedInRegularObj*/ true,
Section ? Section->getFile() : nullptr);
std::tie(S, WasInserted) = insert(
Name, Sym.getType(), Sym.getVisibility(),
/*CanOmitFromDynSym*/ false, /*HasUnnamedAddr*/ false,
/*IsUsedInRegularObj*/ true, Section ? Section->getFile() : nullptr);
int Cmp = compareDefinedNonCommon<ELFT>(S, WasInserted, Sym.getBinding());
if (Cmp > 0)
replaceBody<DefinedRegular<ELFT>>(S, Name, Sym, Section);
@ -406,7 +410,7 @@ Symbol *SymbolTable<ELFT>::addRegular(StringRef Name, uint8_t Binding,
bool WasInserted;
std::tie(S, WasInserted) =
insert(Name, STT_NOTYPE, StOther & 3, /*CanOmitFromDynSym*/ false,
/*IsUsedInRegularObj*/ true, nullptr);
/*HasUnnamedAddr*/ false, /*IsUsedInRegularObj*/ true, nullptr);
int Cmp = compareDefinedNonCommon<ELFT>(S, WasInserted, Binding);
if (Cmp > 0)
replaceBody<DefinedRegular<ELFT>>(S, Name, StOther);
@ -423,6 +427,7 @@ Symbol *SymbolTable<ELFT>::addSynthetic(StringRef N,
bool WasInserted;
std::tie(S, WasInserted) = insert(N, STT_NOTYPE, /*Visibility*/ StOther & 0x3,
/*CanOmitFromDynSym*/ false,
/*HasUnnamedAddr*/ false,
/*IsUsedInRegularObj*/ true, nullptr);
int Cmp = compareDefinedNonCommon<ELFT>(S, WasInserted, STB_GLOBAL);
if (Cmp > 0)
@ -443,7 +448,7 @@ void SymbolTable<ELFT>::addShared(SharedFile<ELFT> *F, StringRef Name,
bool WasInserted;
std::tie(S, WasInserted) =
insert(Name, Sym.getType(), STV_DEFAULT, /*CanOmitFromDynSym*/ true,
/*IsUsedInRegularObj*/ false, F);
/*HasUnnamedAddr*/ false, /*IsUsedInRegularObj*/ false, F);
// Make sure we preempt DSO symbols with default visibility.
if (Sym.getVisibility() == STV_DEFAULT)
S->ExportDynamic = true;
@ -457,11 +462,13 @@ void SymbolTable<ELFT>::addShared(SharedFile<ELFT> *F, StringRef Name,
template <class ELFT>
Symbol *SymbolTable<ELFT>::addBitcode(StringRef Name, bool IsWeak,
uint8_t StOther, uint8_t Type,
bool CanOmitFromDynSym, BitcodeFile *F) {
bool CanOmitFromDynSym,
bool HasUnnamedAddr, BitcodeFile *F) {
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) = insert(Name, Type, StOther & 3, CanOmitFromDynSym,
/*IsUsedInRegularObj*/ false, F);
std::tie(S, WasInserted) =
insert(Name, Type, StOther & 3, CanOmitFromDynSym, HasUnnamedAddr,
/*IsUsedInRegularObj*/ false, F);
int Cmp = compareDefinedNonCommon<ELFT>(S, WasInserted,
IsWeak ? STB_WEAK : STB_GLOBAL);
if (Cmp > 0)

11
lld/ELF/SymbolTable.h
View File

@ -59,7 +59,8 @@ public:
Symbol *addUndefined(StringRef Name);
Symbol *addUndefined(StringRef Name, uint8_t Binding, uint8_t StOther,
uint8_t Type, bool CanOmitFromDynSym, InputFile *File);
uint8_t Type, bool CanOmitFromDynSym,
bool HasUnnamedAddr, InputFile *File);
Symbol *addRegular(StringRef Name, const Elf_Sym &Sym,
InputSectionBase<ELFT> *Section);
@ -72,11 +73,12 @@ public:
void addLazyArchive(ArchiveFile *F, const llvm::object::Archive::Symbol S);
void addLazyObject(StringRef Name, LazyObjectFile &Obj);
Symbol *addBitcode(StringRef Name, bool IsWeak, uint8_t StOther, uint8_t Type,
bool CanOmitFromDynSym, BitcodeFile *File);
bool CanOmitFromDynSym, bool HasUnnamedAddr,
BitcodeFile *File);
Symbol *addCommon(StringRef N, uint64_t Size, uint64_t Alignment,
uint8_t Binding, uint8_t StOther, uint8_t Type,
InputFile *File);
bool HasUnnamedAddr, InputFile *File);
void scanUndefinedFlags();
void scanShlibUndefined();
@ -93,7 +95,8 @@ private:
std::pair<Symbol *, bool> insert(StringRef &Name);
std::pair<Symbol *, bool> insert(StringRef &Name, uint8_t Type,
uint8_t Visibility, bool CanOmitFromDynSym,
bool IsUsedInRegularObj, InputFile *File);
bool HasUnnamedAddr, bool IsUsedInRegularObj,
InputFile *File);
std::string conflictMsg(SymbolBody *Existing, InputFile *NewFile);
void reportDuplicate(SymbolBody *Existing, InputFile *NewFile);

3
lld/ELF/Symbols.h
View File

@ -413,6 +413,9 @@ struct Symbol {
// observed non-DSO symbols.
unsigned Visibility : 2;
// True if the symbol has unnamed_addr.
unsigned HasUnnamedAddr : 1;
// True if the symbol was used for linking and thus need to be added to the
// output file's symbol table. This is true for all symbols except for
// unreferenced DSO symbols and bitcode symbols that are unreferenced except

4
lld/test/ELF/lto/Inputs/unnamed-addr-drop.ll Normal file
View File

@ -0,0 +1,4 @@
target triple = "x86_64-unknown-linux-gnu"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
@foo = unnamed_addr constant i32 42

12
lld/test/ELF/lto/unnamed-addr-drop.ll Normal file
View File

@ -0,0 +1,12 @@
; RUN: llvm-as %s -o %t1.o
; RUN: llvm-as %S/Inputs/unnamed-addr-drop.ll -o %t2.o
; RUN: ld.lld -m elf_x86_64 %t1.o %t2.o -o %t.so -save-temps -shared
; RUN: llvm-dis %t.so.lto.bc -o - | FileCheck %s
target triple = "x86_64-unknown-linux-gnu"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
@foo = weak constant i32 41
; Check that unnamed_addr is dropped during the merge.
; CHECK: @foo = constant i32 42

4
lld/test/ELF/lto/unnamed-addr-lib.ll
View File

@ -11,8 +11,8 @@
; We could add one extra bit for ODR so that we know that preemption is not
; necessary, but that is probably not worth it.
; CHECK: @foo = internal unnamed_addr constant i8 42
; CHECK: @bar = weak_odr unnamed_addr constant i8 42
; CHECK: @foo = internal constant i8 42
; CHECK: @bar = weak_odr constant i8 42
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"