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llvm-project/clang/lib/CodeGen/BackendUtil.cpp

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//===--- BackendUtil.cpp - LLVM Backend Utilities -------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "clang/CodeGen/BackendUtil.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/TargetOptions.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "clang/Frontend/FrontendDiagnostic.h"
#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Assembly/PrintModulePass.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/CodeGen/RegAllocRegistry.h"
#include "llvm/CodeGen/SchedulerRegistry.h"
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/Timer.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/DataLayout.h"
#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/PassManagerBuilder.h"
#include "llvm/Transforms/Scalar.h"
using namespace clang;
using namespace llvm;
namespace {
class EmitAssemblyHelper {
DiagnosticsEngine &Diags;
const CodeGenOptions &CodeGenOpts;
const clang::TargetOptions &TargetOpts;
const LangOptions &LangOpts;
Module *TheModule;
Timer CodeGenerationTime;
mutable PassManager *CodeGenPasses;
mutable PassManager *PerModulePasses;
mutable FunctionPassManager *PerFunctionPasses;
private:
PassManager *getCodeGenPasses(TargetMachine *TM) const {
if (!CodeGenPasses) {
CodeGenPasses = new PassManager();
CodeGenPasses->add(new DataLayout(TheModule));
// Add TargetTransformInfo.
if (TM) {
TargetTransformInfo *TTI =
new TargetTransformInfo(TM->getScalarTargetTransformInfo(),
TM->getVectorTargetTransformInfo());
CodeGenPasses->add(TTI);
}
}
return CodeGenPasses;
}
PassManager *getPerModulePasses(TargetMachine *TM) const {
if (!PerModulePasses) {
PerModulePasses = new PassManager();
PerModulePasses->add(new DataLayout(TheModule));
if (TM) {
TargetTransformInfo *TTI =
new TargetTransformInfo(TM->getScalarTargetTransformInfo(),
TM->getVectorTargetTransformInfo());
PerModulePasses->add(TTI);
}
}
return PerModulePasses;
}
FunctionPassManager *getPerFunctionPasses(TargetMachine *TM) const {
if (!PerFunctionPasses) {
PerFunctionPasses = new FunctionPassManager(TheModule);
PerFunctionPasses->add(new DataLayout(TheModule));
if (TM) {
TargetTransformInfo *TTI =
new TargetTransformInfo(TM->getScalarTargetTransformInfo(),
TM->getVectorTargetTransformInfo());
PerFunctionPasses->add(TTI);
}
}
return PerFunctionPasses;
}
void CreatePasses(TargetMachine *TM);
/// CreateTargetMachine - Generates the TargetMachine.
/// Returns Null if it is unable to create the target machine.
/// Some of our clang tests specify triples which are not built
/// into clang. This is okay because these tests check the generated
/// IR, and they require DataLayout which depends on the triple.
/// In this case, we allow this method to fail and not report an error.
/// When MustCreateTM is used, we print an error if we are unable to load
/// the requested target.
TargetMachine *CreateTargetMachine(bool MustCreateTM);
/// AddEmitPasses - Add passes necessary to emit assembly or LLVM IR.
///
/// \return True on success.
bool AddEmitPasses(BackendAction Action, formatted_raw_ostream &OS,
TargetMachine *TM);
public:
EmitAssemblyHelper(DiagnosticsEngine &_Diags,
const CodeGenOptions &CGOpts,
const clang::TargetOptions &TOpts,
const LangOptions &LOpts,
Module *M)
: Diags(_Diags), CodeGenOpts(CGOpts), TargetOpts(TOpts), LangOpts(LOpts),
TheModule(M), CodeGenerationTime("Code Generation Time"),
CodeGenPasses(0), PerModulePasses(0), PerFunctionPasses(0) {}
~EmitAssemblyHelper() {
delete CodeGenPasses;
delete PerModulePasses;
delete PerFunctionPasses;
}
void EmitAssembly(BackendAction Action, raw_ostream *OS);
};
// We need this wrapper to access LangOpts from extension functions that
// we add to the PassManagerBuilder.
class PassManagerBuilderWrapper : public PassManagerBuilder {
public:
PassManagerBuilderWrapper(const LangOptions &LangOpts)
: PassManagerBuilder(), LangOpts(LangOpts) {}
const LangOptions &getLangOpts() const { return LangOpts; }
private:
const LangOptions &LangOpts;
};
}
static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
if (Builder.OptLevel > 0)
PM.add(createObjCARCAPElimPass());
}
static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
if (Builder.OptLevel > 0)
PM.add(createObjCARCExpandPass());
}
static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
if (Builder.OptLevel > 0)
PM.add(createObjCARCOptPass());
}
static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
PassManagerBase &PM) {
PM.add(createBoundsCheckingPass());
}
static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
PassManagerBase &PM) {
const PassManagerBuilderWrapper &BuilderWrapper =
static_cast<const PassManagerBuilderWrapper&>(Builder);
const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
PM.add(createAddressSanitizerFunctionPass(LangOpts.SanitizeInitOrder,
LangOpts.SanitizeUseAfterReturn,
LangOpts.SanitizeUseAfterScope));
PM.add(createAddressSanitizerModulePass(LangOpts.SanitizeInitOrder));
}
static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
PassManagerBase &PM) {
PM.add(createThreadSanitizerPass());
}
void EmitAssemblyHelper::CreatePasses(TargetMachine *TM) {
unsigned OptLevel = CodeGenOpts.OptimizationLevel;
CodeGenOptions::InliningMethod Inlining = CodeGenOpts.getInlining();
// Handle disabling of LLVM optimization, where we want to preserve the
// internal module before any optimization.
if (CodeGenOpts.DisableLLVMOpts) {
OptLevel = 0;
Inlining = CodeGenOpts.NoInlining;
}
PassManagerBuilderWrapper PMBuilder(LangOpts);
PMBuilder.OptLevel = OptLevel;
PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
PMBuilder.DisableSimplifyLibCalls = !CodeGenOpts.SimplifyLibCalls;
PMBuilder.DisableUnitAtATime = !CodeGenOpts.UnitAtATime;
PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
// In ObjC ARC mode, add the main ARC optimization passes.
if (LangOpts.ObjCAutoRefCount) {
PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
addObjCARCExpandPass);
PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
addObjCARCAPElimPass);
PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
addObjCARCOptPass);
}
if (LangOpts.SanitizeBounds) {
PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
addBoundsCheckingPass);
PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
addBoundsCheckingPass);
}
if (LangOpts.SanitizeAddress) {
PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
addAddressSanitizerPasses);
PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
addAddressSanitizerPasses);
}
if (LangOpts.SanitizeThread) {
PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
addThreadSanitizerPass);
PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
addThreadSanitizerPass);
}
// Figure out TargetLibraryInfo.
Triple TargetTriple(TheModule->getTargetTriple());
PMBuilder.LibraryInfo = new TargetLibraryInfo(TargetTriple);
if (!CodeGenOpts.SimplifyLibCalls)
PMBuilder.LibraryInfo->disableAllFunctions();
switch (Inlining) {
case CodeGenOptions::NoInlining: break;
case CodeGenOptions::NormalInlining: {
// FIXME: Derive these constants in a principled fashion.
unsigned Threshold = 225;
if (CodeGenOpts.OptimizeSize == 1) // -Os
Threshold = 75;
else if (CodeGenOpts.OptimizeSize == 2) // -Oz
Threshold = 25;
else if (OptLevel > 2)
Threshold = 275;
PMBuilder.Inliner = createFunctionInliningPass(Threshold);
break;
}
case CodeGenOptions::OnlyAlwaysInlining:
// Respect always_inline.
if (OptLevel == 0)
// Do not insert lifetime intrinsics at -O0.
PMBuilder.Inliner = createAlwaysInlinerPass(false);
else
PMBuilder.Inliner = createAlwaysInlinerPass();
break;
}
// Set up the per-function pass manager.
FunctionPassManager *FPM = getPerFunctionPasses(TM);
if (CodeGenOpts.VerifyModule)
FPM->add(createVerifierPass());
PMBuilder.populateFunctionPassManager(*FPM);
// Set up the per-module pass manager.
PassManager *MPM = getPerModulePasses(TM);
if (CodeGenOpts.EmitGcovArcs || CodeGenOpts.EmitGcovNotes) {
MPM->add(createGCOVProfilerPass(CodeGenOpts.EmitGcovNotes,
CodeGenOpts.EmitGcovArcs,
TargetTriple.isMacOSX()));
if (CodeGenOpts.getDebugInfo() == CodeGenOptions::NoDebugInfo)
MPM->add(createStripSymbolsPass(true));
}
PMBuilder.populateModulePassManager(*MPM);
}
TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
// Create the TargetMachine for generating code.
std::string Error;
std::string Triple = TheModule->getTargetTriple();
const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
if (!TheTarget) {
if (MustCreateTM)
Diags.Report(diag::err_fe_unable_to_create_target) << Error;
return 0;
}
// FIXME: Expose these capabilities via actual APIs!!!! Aside from just
// being gross, this is also totally broken if we ever care about
// concurrency.
TargetMachine::setAsmVerbosityDefault(CodeGenOpts.AsmVerbose);
TargetMachine::setFunctionSections(CodeGenOpts.FunctionSections);
TargetMachine::setDataSections (CodeGenOpts.DataSections);
// FIXME: Parse this earlier.
llvm::CodeModel::Model CM;
if (CodeGenOpts.CodeModel == "small") {
CM = llvm::CodeModel::Small;
} else if (CodeGenOpts.CodeModel == "kernel") {
CM = llvm::CodeModel::Kernel;
} else if (CodeGenOpts.CodeModel == "medium") {
CM = llvm::CodeModel::Medium;
} else if (CodeGenOpts.CodeModel == "large") {
CM = llvm::CodeModel::Large;
} else {
assert(CodeGenOpts.CodeModel.empty() && "Invalid code model!");
CM = llvm::CodeModel::Default;
}
SmallVector<const char *, 16> BackendArgs;
BackendArgs.push_back("clang"); // Fake program name.
if (!CodeGenOpts.DebugPass.empty()) {
BackendArgs.push_back("-debug-pass");
BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
}
if (!CodeGenOpts.LimitFloatPrecision.empty()) {
BackendArgs.push_back("-limit-float-precision");
BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
}
if (llvm::TimePassesIsEnabled)
BackendArgs.push_back("-time-passes");
for (unsigned i = 0, e = CodeGenOpts.BackendOptions.size(); i != e; ++i)
BackendArgs.push_back(CodeGenOpts.BackendOptions[i].c_str());
if (CodeGenOpts.NoGlobalMerge)
BackendArgs.push_back("-global-merge=false");
BackendArgs.push_back(0);
llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
BackendArgs.data());
std::string FeaturesStr;
if (TargetOpts.Features.size()) {
SubtargetFeatures Features;
for (std::vector<std::string>::const_iterator
it = TargetOpts.Features.begin(),
ie = TargetOpts.Features.end(); it != ie; ++it)
Features.AddFeature(*it);
FeaturesStr = Features.getString();
}
llvm::Reloc::Model RM = llvm::Reloc::Default;
if (CodeGenOpts.RelocationModel == "static") {
RM = llvm::Reloc::Static;
} else if (CodeGenOpts.RelocationModel == "pic") {
RM = llvm::Reloc::PIC_;
} else {
assert(CodeGenOpts.RelocationModel == "dynamic-no-pic" &&
"Invalid PIC model!");
RM = llvm::Reloc::DynamicNoPIC;
}
CodeGenOpt::Level OptLevel = CodeGenOpt::Default;
switch (CodeGenOpts.OptimizationLevel) {
default: break;
case 0: OptLevel = CodeGenOpt::None; break;
case 3: OptLevel = CodeGenOpt::Aggressive; break;
}
llvm::TargetOptions Options;
// Set frame pointer elimination mode.
if (!CodeGenOpts.DisableFPElim) {
Options.NoFramePointerElim = false;
Options.NoFramePointerElimNonLeaf = false;
} else if (CodeGenOpts.OmitLeafFramePointer) {
Options.NoFramePointerElim = false;
Options.NoFramePointerElimNonLeaf = true;
} else {
Options.NoFramePointerElim = true;
Options.NoFramePointerElimNonLeaf = true;
}
if (CodeGenOpts.UseInitArray)
Options.UseInitArray = true;
// Set float ABI type.
if (CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp")
Options.FloatABIType = llvm::FloatABI::Soft;
else if (CodeGenOpts.FloatABI == "hard")
Options.FloatABIType = llvm::FloatABI::Hard;
else {
assert(CodeGenOpts.FloatABI.empty() && "Invalid float abi!");
Options.FloatABIType = llvm::FloatABI::Default;
}
// Set FP fusion mode.
switch (CodeGenOpts.getFPContractMode()) {
case CodeGenOptions::FPC_Off:
Options.AllowFPOpFusion = llvm::FPOpFusion::Strict;
break;
case CodeGenOptions::FPC_On:
Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
break;
case CodeGenOptions::FPC_Fast:
Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
break;
}
Options.LessPreciseFPMADOption = CodeGenOpts.LessPreciseFPMAD;
Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
Options.UseSoftFloat = CodeGenOpts.SoftFloat;
Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
Options.RealignStack = CodeGenOpts.StackRealignment;
Options.DisableTailCalls = CodeGenOpts.DisableTailCalls;
Options.TrapFuncName = CodeGenOpts.TrapFuncName;
Options.PositionIndependentExecutable = LangOpts.PIELevel != 0;
Options.SSPBufferSize = CodeGenOpts.SSPBufferSize;
TargetMachine *TM = TheTarget->createTargetMachine(Triple, TargetOpts.CPU,
FeaturesStr, Options,
RM, CM, OptLevel);
if (CodeGenOpts.RelaxAll)
TM->setMCRelaxAll(true);
if (CodeGenOpts.SaveTempLabels)
TM->setMCSaveTempLabels(true);
if (CodeGenOpts.NoDwarf2CFIAsm)
TM->setMCUseCFI(false);
if (!CodeGenOpts.NoDwarfDirectoryAsm)
TM->setMCUseDwarfDirectory(true);
if (CodeGenOpts.NoExecStack)
TM->setMCNoExecStack(true);
return TM;
}
bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action,
formatted_raw_ostream &OS,
TargetMachine *TM) {
// Create the code generator passes.
PassManager *PM = getCodeGenPasses(TM);
// Add LibraryInfo.
llvm::Triple TargetTriple(TheModule->getTargetTriple());
TargetLibraryInfo *TLI = new TargetLibraryInfo(TargetTriple);
if (!CodeGenOpts.SimplifyLibCalls)
TLI->disableAllFunctions();
PM->add(TLI);
// Add TargetTransformInfo.
PM->add(new TargetTransformInfo(TM->getScalarTargetTransformInfo(),
TM->getVectorTargetTransformInfo()));
// Normal mode, emit a .s or .o file by running the code generator. Note,
// this also adds codegenerator level optimization passes.
TargetMachine::CodeGenFileType CGFT = TargetMachine::CGFT_AssemblyFile;
if (Action == Backend_EmitObj)
CGFT = TargetMachine::CGFT_ObjectFile;
else if (Action == Backend_EmitMCNull)
CGFT = TargetMachine::CGFT_Null;
else
assert(Action == Backend_EmitAssembly && "Invalid action!");
// Add ObjC ARC final-cleanup optimizations. This is done as part of the
// "codegen" passes so that it isn't run multiple times when there is
// inlining happening.
if (LangOpts.ObjCAutoRefCount &&
CodeGenOpts.OptimizationLevel > 0)
PM->add(createObjCARCContractPass());
if (TM->addPassesToEmitFile(*PM, OS, CGFT,
/*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
Diags.Report(diag::err_fe_unable_to_interface_with_target);
return false;
}
return true;
}
void EmitAssemblyHelper::EmitAssembly(BackendAction Action, raw_ostream *OS) {
TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : 0);
llvm::formatted_raw_ostream FormattedOS;
bool UsesCodeGen = (Action != Backend_EmitNothing &&
Action != Backend_EmitBC &&
Action != Backend_EmitLL);
TargetMachine *TM = CreateTargetMachine(UsesCodeGen);
CreatePasses(TM);
switch (Action) {
case Backend_EmitNothing:
break;
case Backend_EmitBC:
getPerModulePasses(TM)->add(createBitcodeWriterPass(*OS));
break;
case Backend_EmitLL:
FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
getPerModulePasses(TM)->add(createPrintModulePass(&FormattedOS));
break;
default:
FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
if (!AddEmitPasses(Action, FormattedOS, TM))
return;
}
// Before executing passes, print the final values of the LLVM options.
cl::PrintOptionValues();
// Run passes. For now we do all passes at once, but eventually we
// would like to have the option of streaming code generation.
if (PerFunctionPasses) {
PrettyStackTraceString CrashInfo("Per-function optimization");
PerFunctionPasses->doInitialization();
for (Module::iterator I = TheModule->begin(),
E = TheModule->end(); I != E; ++I)
if (!I->isDeclaration())
PerFunctionPasses->run(*I);
PerFunctionPasses->doFinalization();
}
if (PerModulePasses) {
PrettyStackTraceString CrashInfo("Per-module optimization passes");
PerModulePasses->run(*TheModule);
}
if (CodeGenPasses) {
PrettyStackTraceString CrashInfo("Code generation");
CodeGenPasses->run(*TheModule);
}
}
void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
const CodeGenOptions &CGOpts,
const clang::TargetOptions &TOpts,
const LangOptions &LOpts,
Module *M,
BackendAction Action, raw_ostream *OS) {
EmitAssemblyHelper AsmHelper(Diags, CGOpts, TOpts, LOpts, M);
AsmHelper.EmitAssembly(Action, OS);
}
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