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CodeGen, Target: Move Mach-O-specific symbol name logic to Mach-O lowering. 

A profile of an LTO link of Chrome revealed that we were spending some
~30-50% of execution time in the function Constant::getRelocationInfo(),
which is called from TargetLoweringObjectFile::getKindForGlobal() and in turn
from TargetMachine::getNameWithPrefix().

It turns out that we only need the result of getKindForGlobal() when
targeting Mach-O, so this change moves the relevant part of the logic to
TargetLoweringObjectFileMachO.

NFCI.

Differential Revision: http://reviews.llvm.org/D14168

llvm-svn: 252014
This commit is contained in:
Peter Collingbourne 2015-11-03 23:40:03 +00:00
parent 26014690aa
commit 94d778697a
5 changed files with 37 additions and 27 deletions
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6
llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
View File

@ -123,6 +123,9 @@ public:
const MCValue &MV, int64_t Offset,
MachineModuleInfo *MMI,
MCStreamer &Streamer) const override;
void getNameWithPrefix(SmallVectorImpl<char> &OutName, const GlobalValue *GV,
Mangler &Mang, const TargetMachine &TM) const override;
};
@ -140,8 +143,7 @@ public:
const TargetMachine &TM) const override;
void getNameWithPrefix(SmallVectorImpl<char> &OutName, const GlobalValue *GV,
bool CannotUsePrivateLabel, Mangler &Mang,
const TargetMachine &TM) const override;
Mangler &Mang, const TargetMachine &TM) const override;
MCSection *getSectionForJumpTable(const Function &F, Mangler &Mang,
const TargetMachine &TM) const override;

3
llvm/include/llvm/Target/TargetLoweringObjectFile.h
View File

@ -93,8 +93,7 @@ public:
}
virtual void getNameWithPrefix(SmallVectorImpl<char> &OutName,
const GlobalValue *GV,
bool CannotUsePrivateLabel, Mangler &Mang,
const GlobalValue *GV, Mangler &Mang,
const TargetMachine &TM) const;
virtual MCSection *getSectionForJumpTable(const Function &F, Mangler &Mang,

31
llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
View File

@ -24,6 +24,7 @@
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSectionCOFF.h"
@ -763,6 +764,29 @@ const MCExpr *TargetLoweringObjectFileMachO::getIndirectSymViaGOTPCRel(
return MCBinaryExpr::createSub(LHS, RHS, Ctx);
}
static bool canUsePrivateLabel(const MCAsmInfo &AsmInfo,
const MCSection &Section) {
if (!AsmInfo.isSectionAtomizableBySymbols(Section))
return true;
// If it is not dead stripped, it is safe to use private labels.
const MCSectionMachO &SMO = cast<MCSectionMachO>(Section);
if (SMO.hasAttribute(MachO::S_ATTR_NO_DEAD_STRIP))
return true;
return false;
}
void TargetLoweringObjectFileMachO::getNameWithPrefix(
SmallVectorImpl<char> &OutName, const GlobalValue *GV, Mangler &Mang,
const TargetMachine &TM) const {
SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
const MCSection *TheSection = SectionForGlobal(GV, GVKind, Mang, TM);
bool CannotUsePrivateLabel =
!canUsePrivateLabel(*TM.getMCAsmInfo(), *TheSection);
Mang.getNameWithPrefix(OutName, GV, CannotUsePrivateLabel);
}
//===----------------------------------------------------------------------===//
// COFF
//===----------------------------------------------------------------------===//
@ -918,7 +942,7 @@ MCSection *TargetLoweringObjectFileCOFF::SelectSectionForGlobal(
COMDATSymName, Selection);
} else {
SmallString<256> TmpData;
getNameWithPrefix(TmpData, GV, /*CannotUsePrivateLabel=*/true, Mang, TM);
Mang.getNameWithPrefix(TmpData, GV, /*CannotUsePrivateLabel=*/true);
return getContext().getCOFFSection(Name, Characteristics, Kind, TmpData,
Selection);
}
@ -943,8 +967,9 @@ MCSection *TargetLoweringObjectFileCOFF::SelectSectionForGlobal(
}
void TargetLoweringObjectFileCOFF::getNameWithPrefix(
SmallVectorImpl<char> &OutName, const GlobalValue *GV,
bool CannotUsePrivateLabel, Mangler &Mang, const TargetMachine &TM) const {
SmallVectorImpl<char> &OutName, const GlobalValue *GV, Mangler &Mang,
const TargetMachine &TM) const {
bool CannotUsePrivateLabel = false;
if (GV->hasPrivateLinkage() &&
((isa<Function>(GV) && TM.getFunctionSections()) ||
(isa<GlobalVariable>(GV) && TM.getDataSections())))

6
llvm/lib/Target/TargetLoweringObjectFile.cpp
View File

@ -344,7 +344,7 @@ const MCExpr *TargetLoweringObjectFile::getDebugThreadLocalSymbol(const MCSymbol
}
void TargetLoweringObjectFile::getNameWithPrefix(
SmallVectorImpl<char> &OutName, const GlobalValue *GV,
bool CannotUsePrivateLabel, Mangler &Mang, const TargetMachine &TM) const {
Mang.getNameWithPrefix(OutName, GV, CannotUsePrivateLabel);
SmallVectorImpl<char> &OutName, const GlobalValue *GV, Mangler &Mang,
const TargetMachine &TM) const {
Mang.getNameWithPrefix(OutName, GV, /*CannotUsePrivateLabel=*/false);
}

18
llvm/lib/Target/TargetMachine.cpp
View File

@ -155,19 +155,6 @@ TargetIRAnalysis TargetMachine::getTargetIRAnalysis() {
});
}
static bool canUsePrivateLabel(const MCAsmInfo &AsmInfo,
const MCSection &Section) {
if (!AsmInfo.isSectionAtomizableBySymbols(Section))
return true;
// If it is not dead stripped, it is safe to use private labels.
const MCSectionMachO &SMO = cast<MCSectionMachO>(Section);
if (SMO.hasAttribute(MachO::S_ATTR_NO_DEAD_STRIP))
return true;
return false;
}
void TargetMachine::getNameWithPrefix(SmallVectorImpl<char> &Name,
const GlobalValue *GV, Mangler &Mang,
bool MayAlwaysUsePrivate) const {
@ -177,11 +164,8 @@ void TargetMachine::getNameWithPrefix(SmallVectorImpl<char> &Name,
Mang.getNameWithPrefix(Name, GV, false);
return;
}
SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, *this);
const TargetLoweringObjectFile *TLOF = getObjFileLowering();
const MCSection *TheSection = TLOF->SectionForGlobal(GV, GVKind, Mang, *this);
bool CannotUsePrivateLabel = !canUsePrivateLabel(*AsmInfo, *TheSection);
TLOF->getNameWithPrefix(Name, GV, CannotUsePrivateLabel, Mang, *this);
TLOF->getNameWithPrefix(Name, GV, Mang, *this);
}
MCSymbol *TargetMachine::getSymbol(const GlobalValue *GV, Mangler &Mang) const {