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[MS][ARM64] Hoist __ImageBase handling into TargetLoweringObjectFileCOFF

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All COFF targets should use @IMGREL32 relocations for symbol differences
against __ImageBase. Do the same for getSectionForConstant, so that
immediates lowered to globals get merged across TUs.

Patch by Chris January

Differential Revision: https://reviews.llvm.org/D47783

llvm-svn: 334523
This commit is contained in:
Reid Kleckner 2018-06-12 18:56:05 +00:00
parent fb41a59565
commit aeb232db7c
6 changed files with 126 additions and 112 deletions
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10
include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
View File

@ -163,6 +163,16 @@ public:
void emitLinkerFlagsForUsed(raw_ostream &OS,
const GlobalValue *GV) const override;
const MCExpr *lowerRelativeReference(const GlobalValue *LHS,
const GlobalValue *RHS,
const TargetMachine &TM) const override;
/// Given a mergeable constant with the specified size and relocation
/// information, return a section that it should be placed in.
MCSection *getSectionForConstant(const DataLayout &DL, SectionKind Kind,
const Constant *C,
unsigned &Align) const override;
};
class TargetLoweringObjectFileWasm : public TargetLoweringObjectFile {

105
lib/CodeGen/TargetLoweringObjectFileImpl.cpp
View File

@ -1274,6 +1274,111 @@ void TargetLoweringObjectFileCOFF::emitLinkerFlagsForUsed(
emitLinkerFlagsForUsedCOFF(OS, GV, getTargetTriple(), getMangler());
}
const MCExpr *TargetLoweringObjectFileCOFF::lowerRelativeReference(
const GlobalValue *LHS, const GlobalValue *RHS,
const TargetMachine &TM) const {
const Triple &T = TM.getTargetTriple();
if (!T.isKnownWindowsMSVCEnvironment() &&
!T.isWindowsItaniumEnvironment() &&
!T.isWindowsCoreCLREnvironment())
return nullptr;
// Our symbols should exist in address space zero, cowardly no-op if
// otherwise.
if (LHS->getType()->getPointerAddressSpace() != 0 ||
RHS->getType()->getPointerAddressSpace() != 0)
return nullptr;
// Both ptrtoint instructions must wrap global objects:
// - Only global variables are eligible for image relative relocations.
// - The subtrahend refers to the special symbol __ImageBase, a GlobalVariable.
// We expect __ImageBase to be a global variable without a section, externally
// defined.
//
// It should look something like this: @__ImageBase = external constant i8
if (!isa<GlobalObject>(LHS) || !isa<GlobalVariable>(RHS) ||
LHS->isThreadLocal() || RHS->isThreadLocal() ||
RHS->getName() != "__ImageBase" || !RHS->hasExternalLinkage() ||
cast<GlobalVariable>(RHS)->hasInitializer() || RHS->hasSection())
return nullptr;
return MCSymbolRefExpr::create(TM.getSymbol(LHS),
MCSymbolRefExpr::VK_COFF_IMGREL32,
getContext());
}
static std::string APIntToHexString(const APInt &AI) {
unsigned Width = (AI.getBitWidth() / 8) * 2;
std::string HexString = utohexstr(AI.getLimitedValue(), /*LowerCase=*/true);
unsigned Size = HexString.size();
assert(Width >= Size && "hex string is too large!");
HexString.insert(HexString.begin(), Width - Size, '0');
return HexString;
}
static std::string scalarConstantToHexString(const Constant *C) {
Type *Ty = C->getType();
if (isa<UndefValue>(C)) {
return APIntToHexString(APInt::getNullValue(Ty->getPrimitiveSizeInBits()));
} else if (const auto *CFP = dyn_cast<ConstantFP>(C)) {
return APIntToHexString(CFP->getValueAPF().bitcastToAPInt());
} else if (const auto *CI = dyn_cast<ConstantInt>(C)) {
return APIntToHexString(CI->getValue());
} else {
unsigned NumElements;
if (isa<VectorType>(Ty))
NumElements = Ty->getVectorNumElements();
else
NumElements = Ty->getArrayNumElements();
std::string HexString;
for (int I = NumElements - 1, E = -1; I != E; --I)
HexString += scalarConstantToHexString(C->getAggregateElement(I));
return HexString;
}
}
MCSection *TargetLoweringObjectFileCOFF::getSectionForConstant(
const DataLayout &DL, SectionKind Kind, const Constant *C,
unsigned &Align) const {
if (Kind.isMergeableConst() && C) {
const unsigned Characteristics = COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_LNK_COMDAT;
std::string COMDATSymName;
if (Kind.isMergeableConst4()) {
if (Align <= 4) {
COMDATSymName = "__real@" + scalarConstantToHexString(C);
Align = 4;
}
} else if (Kind.isMergeableConst8()) {
if (Align <= 8) {
COMDATSymName = "__real@" + scalarConstantToHexString(C);
Align = 8;
}
} else if (Kind.isMergeableConst16()) {
// FIXME: These may not be appropriate for non-x86 architectures.
if (Align <= 16) {
COMDATSymName = "__xmm@" + scalarConstantToHexString(C);
Align = 16;
}
} else if (Kind.isMergeableConst32()) {
if (Align <= 32) {
COMDATSymName = "__ymm@" + scalarConstantToHexString(C);
Align = 32;
}
}
if (!COMDATSymName.empty())
return getContext().getCOFFSection(".rdata", Characteristics, Kind,
COMDATSymName,
COFF::IMAGE_COMDAT_SELECT_ANY);
}
return TargetLoweringObjectFile::getSectionForConstant(DL, Kind, C, Align);
}
//===----------------------------------------------------------------------===//
// Wasm
//===----------------------------------------------------------------------===//

2
lib/Target/X86/X86TargetMachine.cpp
View File

@ -105,8 +105,6 @@ static std::unique_ptr<TargetLoweringObjectFile> createTLOF(const Triple &TT) {
return llvm::make_unique<X86FuchsiaTargetObjectFile>();
if (TT.isOSBinFormatELF())
return llvm::make_unique<X86ELFTargetObjectFile>();
if (TT.isKnownWindowsMSVCEnvironment() || TT.isWindowsCoreCLREnvironment())
return llvm::make_unique<X86WindowsTargetObjectFile>();
if (TT.isOSBinFormatCOFF())
return llvm::make_unique<TargetLoweringObjectFileCOFF>();
llvm_unreachable("unknown subtarget type");

97
lib/Target/X86/X86TargetObjectFile.cpp
View File

@ -91,100 +91,3 @@ void X86SolarisTargetObjectFile::Initialize(MCContext &Ctx,
TargetLoweringObjectFileELF::Initialize(Ctx, TM);
InitializeELF(TM.Options.UseInitArray);
}
const MCExpr *X86WindowsTargetObjectFile::lowerRelativeReference(
const GlobalValue *LHS, const GlobalValue *RHS,
const TargetMachine &TM) const {
// Our symbols should exist in address space zero, cowardly no-op if
// otherwise.
if (LHS->getType()->getPointerAddressSpace() != 0 ||
RHS->getType()->getPointerAddressSpace() != 0)
return nullptr;
// Both ptrtoint instructions must wrap global objects:
// - Only global variables are eligible for image relative relocations.
// - The subtrahend refers to the special symbol __ImageBase, a GlobalVariable.
// We expect __ImageBase to be a global variable without a section, externally
// defined.
//
// It should look something like this: @__ImageBase = external constant i8
if (!isa<GlobalObject>(LHS) || !isa<GlobalVariable>(RHS) ||
LHS->isThreadLocal() || RHS->isThreadLocal() ||
RHS->getName() != "__ImageBase" || !RHS->hasExternalLinkage() ||
cast<GlobalVariable>(RHS)->hasInitializer() || RHS->hasSection())
return nullptr;
return MCSymbolRefExpr::create(TM.getSymbol(LHS),
MCSymbolRefExpr::VK_COFF_IMGREL32,
getContext());
}
static std::string APIntToHexString(const APInt &AI) {
unsigned Width = (AI.getBitWidth() / 8) * 2;
std::string HexString = utohexstr(AI.getLimitedValue(), /*LowerCase=*/true);
unsigned Size = HexString.size();
assert(Width >= Size && "hex string is too large!");
HexString.insert(HexString.begin(), Width - Size, '0');
return HexString;
}
static std::string scalarConstantToHexString(const Constant *C) {
Type *Ty = C->getType();
if (isa<UndefValue>(C)) {
return APIntToHexString(APInt::getNullValue(Ty->getPrimitiveSizeInBits()));
} else if (const auto *CFP = dyn_cast<ConstantFP>(C)) {
return APIntToHexString(CFP->getValueAPF().bitcastToAPInt());
} else if (const auto *CI = dyn_cast<ConstantInt>(C)) {
return APIntToHexString(CI->getValue());
} else {
unsigned NumElements;
if (isa<VectorType>(Ty))
NumElements = Ty->getVectorNumElements();
else
NumElements = Ty->getArrayNumElements();
std::string HexString;
for (int I = NumElements - 1, E = -1; I != E; --I)
HexString += scalarConstantToHexString(C->getAggregateElement(I));
return HexString;
}
}
MCSection *X86WindowsTargetObjectFile::getSectionForConstant(
const DataLayout &DL, SectionKind Kind, const Constant *C,
unsigned &Align) const {
if (Kind.isMergeableConst() && C) {
const unsigned Characteristics = COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_LNK_COMDAT;
std::string COMDATSymName;
if (Kind.isMergeableConst4()) {
if (Align <= 4) {
COMDATSymName = "__real@" + scalarConstantToHexString(C);
Align = 4;
}
} else if (Kind.isMergeableConst8()) {
if (Align <= 8) {
COMDATSymName = "__real@" + scalarConstantToHexString(C);
Align = 8;
}
} else if (Kind.isMergeableConst16()) {
if (Align <= 16) {
COMDATSymName = "__xmm@" + scalarConstantToHexString(C);
Align = 16;
}
} else if (Kind.isMergeableConst32()) {
if (Align <= 32) {
COMDATSymName = "__ymm@" + scalarConstantToHexString(C);
Align = 32;
}
}
if (!COMDATSymName.empty())
return getContext().getCOFFSection(".rdata", Characteristics, Kind,
COMDATSymName,
COFF::IMAGE_COMDAT_SELECT_ANY);
}
return TargetLoweringObjectFile::getSectionForConstant(DL, Kind, C, Align);
}

13
lib/Target/X86/X86TargetObjectFile.h
View File

@ -71,19 +71,6 @@ namespace llvm {
void Initialize(MCContext &Ctx, const TargetMachine &TM) override;
};
/// This implementation is used for Windows targets on x86 and x86-64.
class X86WindowsTargetObjectFile : public TargetLoweringObjectFileCOFF {
const MCExpr *
lowerRelativeReference(const GlobalValue *LHS, const GlobalValue *RHS,
const TargetMachine &TM) const override;
/// Given a mergeable constant with the specified size and relocation
/// information, return a section that it should be placed in.
MCSection *getSectionForConstant(const DataLayout &DL, SectionKind Kind,
const Constant *C,
unsigned &Align) const override;
};
} // end namespace llvm
#endif

11
test/MC/AArch64/ir-to-imgrel.ll Normal file
View File

@ -0,0 +1,11 @@
; RUN: llc -mtriple=aarch64-pc-win32 %s -o - | FileCheck %s --check-prefix=AARCH64
@__ImageBase = external global i8
; AARCH64: .xword "?x@@3HA"@IMGREL
@"\01?x@@3HA" = global i64 sub nsw (i64 ptrtoint (i64* @"\01?x@@3HA" to i64), i64 ptrtoint (i8* @__ImageBase to i64)), align 8
declare void @f()
; AARCH64: .xword f@IMGREL
@fp = global i64 sub nsw (i64 ptrtoint (void ()* @f to i64), i64 ptrtoint (i8* @__ImageBase to i64)), align 8