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llvm-project/clang/lib/CodeGen/BackendUtil.cpp
Chandler Carruth 097d019c6c Wire up -fpie and -fPIE to LLVM's newly added TargetOptions. No test 
case as we don't currently have any way of dumping target options or
otherwise observing this. Another small step toward fixing PR12380. With
this we generate TLS accesses using the static model instead of the
dynamic model, but we're still generating suboptimal code under the
mistaken assumption that the TLS offset might be greater than 2^32, and
therefor not viable as an immediate offset of a segment register.

llvm-svn: 154298
2012-04-08 21:09:51 +00:00

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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/Target/TargetData.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() const {
if (!CodeGenPasses) {
CodeGenPasses = new PassManager();
CodeGenPasses->add(new TargetData(TheModule));
}
return CodeGenPasses;
}
PassManager *getPerModulePasses() const {
if (!PerModulePasses) {
PerModulePasses = new PassManager();
PerModulePasses->add(new TargetData(TheModule));
}
return PerModulePasses;
}
FunctionPassManager *getPerFunctionPasses() const {
if (!PerFunctionPasses) {
PerFunctionPasses = new FunctionPassManager(TheModule);
PerFunctionPasses->add(new TargetData(TheModule));
}
return PerFunctionPasses;
}
void CreatePasses();
/// AddEmitPasses - Add passes necessary to emit assembly or LLVM IR.
///
/// \return True on success.
bool AddEmitPasses(BackendAction Action, formatted_raw_ostream &OS);
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);
};
}
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 addAddressSanitizerPass(const PassManagerBuilder &Builder,
PassManagerBase &PM) {
PM.add(createAddressSanitizerPass());
}
static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
PassManagerBase &PM) {
PM.add(createThreadSanitizerPass());
}
void EmitAssemblyHelper::CreatePasses() {
unsigned OptLevel = CodeGenOpts.OptimizationLevel;
CodeGenOptions::InliningMethod Inlining = CodeGenOpts.Inlining;
// Handle disabling of LLVM optimization, where we want to preserve the
// internal module before any optimization.
if (CodeGenOpts.DisableLLVMOpts) {
OptLevel = 0;
Inlining = CodeGenOpts.NoInlining;
}
PassManagerBuilder PMBuilder;
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.AddressSanitizer) {
PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
addAddressSanitizerPass);
PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
addAddressSanitizerPass);
}
if (LangOpts.ThreadSanitizer) {
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();
if (CodeGenOpts.VerifyModule)
FPM->add(createVerifierPass());
PMBuilder.populateFunctionPassManager(*FPM);
// Set up the per-module pass manager.
PassManager *MPM = getPerModulePasses();
if (CodeGenOpts.EmitGcovArcs || CodeGenOpts.EmitGcovNotes) {
MPM->add(createGCOVProfilerPass(CodeGenOpts.EmitGcovNotes,
CodeGenOpts.EmitGcovArcs,
TargetTriple.isMacOSX()));
if (!CodeGenOpts.DebugInfo)
MPM->add(createStripSymbolsPass(true));
}
PMBuilder.populateModulePassManager(*MPM);
}
bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action,
formatted_raw_ostream &OS) {
// Create the TargetMachine for generating code.
std::string Error;
std::string Triple = TheModule->getTargetTriple();
const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
if (!TheTarget) {
Diags.Report(diag::err_fe_unable_to_create_target) << Error;
return false;
}
// 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;
}
// 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;
}
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;
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);
// Create the code generator passes.
PassManager *PM = getCodeGenPasses();
// Add LibraryInfo.
TargetLibraryInfo *TLI = new TargetLibraryInfo();
if (!CodeGenOpts.SimplifyLibCalls)
TLI->disableAllFunctions();
PM->add(TLI);
// 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;
CreatePasses();
switch (Action) {
case Backend_EmitNothing:
break;
case Backend_EmitBC:
getPerModulePasses()->add(createBitcodeWriterPass(*OS));
break;
case Backend_EmitLL:
FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
getPerModulePasses()->add(createPrintModulePass(&FormattedOS));
break;
default:
FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
if (!AddEmitPasses(Action, FormattedOS))
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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