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Diffstat (limited to 'lib/LTO/LTOCodeGenerator.cpp')
| -rw-r--r-- | lib/LTO/LTOCodeGenerator.cpp | 453 |
1 files changed, 453 insertions, 0 deletions
diff --git a/lib/LTO/LTOCodeGenerator.cpp b/lib/LTO/LTOCodeGenerator.cpp new file mode 100644 index 0000000000..22e9754bcf --- /dev/null +++ b/lib/LTO/LTOCodeGenerator.cpp @@ -0,0 +1,453 @@ +//===-LTOCodeGenerator.cpp - LLVM Link Time Optimizer ---------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements the Link Time Optimization library. This library is +// intended to be used by linker to optimize code at link time. +// +//===----------------------------------------------------------------------===// + +#include "llvm/LTO/LTOCodeGenerator.h" +#include "llvm/LTO/LTOModule.h" +#include "llvm/ADT/StringExtras.h" +#include "llvm/Analysis/Passes.h" +#include "llvm/Analysis/Verifier.h" +#include "llvm/Bitcode/ReaderWriter.h" +#include "llvm/Config/config.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/DerivedTypes.h" +#include "llvm/IR/LLVMContext.h" +#include "llvm/IR/Module.h" +#include "llvm/InitializePasses.h" +#include "llvm/Linker.h" +#include "llvm/MC/MCAsmInfo.h" +#include "llvm/MC/MCContext.h" +#include "llvm/MC/SubtargetFeature.h" +#include "llvm/PassManager.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/FileSystem.h" +#include "llvm/Support/FormattedStream.h" +#include "llvm/Support/Host.h" +#include "llvm/Support/MemoryBuffer.h" +#include "llvm/Support/Signals.h" +#include "llvm/Support/TargetRegistry.h" +#include "llvm/Support/TargetSelect.h" +#include "llvm/Support/ToolOutputFile.h" +#include "llvm/Support/system_error.h" +#include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/Target/Mangler.h" +#include "llvm/Transforms/IPO.h" +#include "llvm/Transforms/IPO/PassManagerBuilder.h" +#include "llvm/Transforms/ObjCARC.h" +using namespace llvm; + +static cl::opt<bool> +DisableOpt("disable-opt", cl::init(false), + cl::desc("Do not run any optimization passes")); + +static cl::opt<bool> +DisableInline("disable-inlining", cl::init(false), + cl::desc("Do not run the inliner pass")); + +static cl::opt<bool> +DisableGVNLoadPRE("disable-gvn-loadpre", cl::init(false), + cl::desc("Do not run the GVN load PRE pass")); + +const char* LTOCodeGenerator::getVersionString() { +#ifdef LLVM_VERSION_INFO + return PACKAGE_NAME " version " PACKAGE_VERSION ", " LLVM_VERSION_INFO; +#else + return PACKAGE_NAME " version " PACKAGE_VERSION; +#endif +} + +LTOCodeGenerator::LTOCodeGenerator() + : Context(getGlobalContext()), Linker(new Module("ld-temp.o", Context)), + TargetMach(NULL), EmitDwarfDebugInfo(false), ScopeRestrictionsDone(false), + CodeModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC), NativeObjectFile(NULL) { + initializeLTOPasses(); +} + +LTOCodeGenerator::~LTOCodeGenerator() { + delete TargetMach; + delete NativeObjectFile; + delete Linker.getModule(); + + for (std::vector<char *>::iterator I = CodegenOptions.begin(), + E = CodegenOptions.end(); + I != E; ++I) + free(*I); +} + +// Initialize LTO passes. Please keep this funciton in sync with +// PassManagerBuilder::populateLTOPassManager(), and make sure all LTO +// passes are initialized. +// +void LTOCodeGenerator::initializeLTOPasses() { + PassRegistry &R = *PassRegistry::getPassRegistry(); + + initializeInternalizePassPass(R); + initializeIPSCCPPass(R); + initializeGlobalOptPass(R); + initializeConstantMergePass(R); + initializeDAHPass(R); + initializeInstCombinerPass(R); + initializeSimpleInlinerPass(R); + initializePruneEHPass(R); + initializeGlobalDCEPass(R); + initializeArgPromotionPass(R); + initializeJumpThreadingPass(R); + initializeSROAPass(R); + initializeSROA_DTPass(R); + initializeSROA_SSAUpPass(R); + initializeFunctionAttrsPass(R); + initializeGlobalsModRefPass(R); + initializeLICMPass(R); + initializeGVNPass(R); + initializeMemCpyOptPass(R); + initializeDCEPass(R); + initializeCFGSimplifyPassPass(R); +} + +bool LTOCodeGenerator::addModule(LTOModule* mod, std::string& errMsg) { + bool ret = Linker.linkInModule(mod->getLLVVMModule(), &errMsg); + + const std::vector<const char*> &undefs = mod->getAsmUndefinedRefs(); + for (int i = 0, e = undefs.size(); i != e; ++i) + AsmUndefinedRefs[undefs[i]] = 1; + + return !ret; +} + +void LTOCodeGenerator::setDebugInfo(lto_debug_model debug) { + switch (debug) { + case LTO_DEBUG_MODEL_NONE: + EmitDwarfDebugInfo = false; + return; + + case LTO_DEBUG_MODEL_DWARF: + EmitDwarfDebugInfo = true; + return; + } + llvm_unreachable("Unknown debug format!"); +} + +void LTOCodeGenerator::setCodePICModel(lto_codegen_model model) { + switch (model) { + case LTO_CODEGEN_PIC_MODEL_STATIC: + case LTO_CODEGEN_PIC_MODEL_DYNAMIC: + case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC: + CodeModel = model; + return; + } + llvm_unreachable("Unknown PIC model!"); +} + +bool LTOCodeGenerator::writeMergedModules(const char *path, + std::string &errMsg) { + if (!determineTarget(errMsg)) + return false; + + // mark which symbols can not be internalized + applyScopeRestrictions(); + + // create output file + std::string ErrInfo; + tool_output_file Out(path, ErrInfo, sys::fs::F_Binary); + if (!ErrInfo.empty()) { + errMsg = "could not open bitcode file for writing: "; + errMsg += path; + return false; + } + + // write bitcode to it + WriteBitcodeToFile(Linker.getModule(), Out.os()); + Out.os().close(); + + if (Out.os().has_error()) { + errMsg = "could not write bitcode file: "; + errMsg += path; + Out.os().clear_error(); + return false; + } + + Out.keep(); + return true; +} + +bool LTOCodeGenerator::compile_to_file(const char** name, std::string& errMsg) { + // make unique temp .o file to put generated object file + SmallString<128> Filename; + int FD; + error_code EC = sys::fs::createTemporaryFile("lto-llvm", "o", FD, Filename); + if (EC) { + errMsg = EC.message(); + return false; + } + + // generate object file + tool_output_file objFile(Filename.c_str(), FD); + + bool genResult = generateObjectFile(objFile.os(), errMsg); + objFile.os().close(); + if (objFile.os().has_error()) { + objFile.os().clear_error(); + sys::fs::remove(Twine(Filename)); + return false; + } + + objFile.keep(); + if (!genResult) { + sys::fs::remove(Twine(Filename)); + return false; + } + + NativeObjectPath = Filename.c_str(); + *name = NativeObjectPath.c_str(); + return true; +} + +const void* LTOCodeGenerator::compile(size_t* length, std::string& errMsg) { + const char *name; + if (!compile_to_file(&name, errMsg)) + return NULL; + + // remove old buffer if compile() called twice + delete NativeObjectFile; + + // read .o file into memory buffer + OwningPtr<MemoryBuffer> BuffPtr; + if (error_code ec = MemoryBuffer::getFile(name, BuffPtr, -1, false)) { + errMsg = ec.message(); + sys::fs::remove(NativeObjectPath); + return NULL; + } + NativeObjectFile = BuffPtr.take(); + + // remove temp files + sys::fs::remove(NativeObjectPath); + + // return buffer, unless error + if (NativeObjectFile == NULL) + return NULL; + *length = NativeObjectFile->getBufferSize(); + return NativeObjectFile->getBufferStart(); +} + +bool LTOCodeGenerator::determineTarget(std::string &errMsg) { + if (TargetMach != NULL) + return true; + + // if options were requested, set them + if (!CodegenOptions.empty()) + cl::ParseCommandLineOptions(CodegenOptions.size(), + const_cast<char **>(&CodegenOptions[0])); + + std::string TripleStr = Linker.getModule()->getTargetTriple(); + if (TripleStr.empty()) + TripleStr = sys::getDefaultTargetTriple(); + llvm::Triple Triple(TripleStr); + + // create target machine from info for merged modules + const Target *march = TargetRegistry::lookupTarget(TripleStr, errMsg); + if (march == NULL) + return false; + + // The relocation model is actually a static member of TargetMachine and + // needs to be set before the TargetMachine is instantiated. + Reloc::Model RelocModel = Reloc::Default; + switch (CodeModel) { + case LTO_CODEGEN_PIC_MODEL_STATIC: + RelocModel = Reloc::Static; + break; + case LTO_CODEGEN_PIC_MODEL_DYNAMIC: + RelocModel = Reloc::PIC_; + break; + case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC: + RelocModel = Reloc::DynamicNoPIC; + break; + } + + // construct LTOModule, hand over ownership of module and target + SubtargetFeatures Features; + Features.getDefaultSubtargetFeatures(Triple); + std::string FeatureStr = Features.getString(); + // Set a default CPU for Darwin triples. + if (MCpu.empty() && Triple.isOSDarwin()) { + if (Triple.getArch() == llvm::Triple::x86_64) + MCpu = "core2"; + else if (Triple.getArch() == llvm::Triple::x86) + MCpu = "yonah"; + } + TargetOptions Options; + LTOModule::getTargetOptions(Options); + TargetMach = march->createTargetMachine(TripleStr, MCpu, FeatureStr, Options, + RelocModel, CodeModel::Default, + CodeGenOpt::Aggressive); + return true; +} + +void LTOCodeGenerator:: +applyRestriction(GlobalValue &GV, + std::vector<const char*> &MustPreserveList, + SmallPtrSet<GlobalValue*, 8> &AsmUsed, + Mangler &Mangler) { + SmallString<64> Buffer; + Mangler.getNameWithPrefix(Buffer, &GV, false); + + if (GV.isDeclaration()) + return; + if (MustPreserveSymbols.count(Buffer)) + MustPreserveList.push_back(GV.getName().data()); + if (AsmUndefinedRefs.count(Buffer)) + AsmUsed.insert(&GV); +} + +static void findUsedValues(GlobalVariable *LLVMUsed, + SmallPtrSet<GlobalValue*, 8> &UsedValues) { + if (LLVMUsed == 0) return; + + ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer()); + for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i) + if (GlobalValue *GV = + dyn_cast<GlobalValue>(Inits->getOperand(i)->stripPointerCasts())) + UsedValues.insert(GV); +} + +void LTOCodeGenerator::applyScopeRestrictions() { + if (ScopeRestrictionsDone) + return; + Module *mergedModule = Linker.getModule(); + + // Start off with a verification pass. + PassManager passes; + passes.add(createVerifierPass()); + + // mark which symbols can not be internalized + MCContext MContext(TargetMach->getMCAsmInfo(), TargetMach->getRegisterInfo(), + NULL); + Mangler Mangler(MContext, TargetMach); + std::vector<const char*> MustPreserveList; + SmallPtrSet<GlobalValue*, 8> AsmUsed; + + for (Module::iterator f = mergedModule->begin(), + e = mergedModule->end(); f != e; ++f) + applyRestriction(*f, MustPreserveList, AsmUsed, Mangler); + for (Module::global_iterator v = mergedModule->global_begin(), + e = mergedModule->global_end(); v != e; ++v) + applyRestriction(*v, MustPreserveList, AsmUsed, Mangler); + for (Module::alias_iterator a = mergedModule->alias_begin(), + e = mergedModule->alias_end(); a != e; ++a) + applyRestriction(*a, MustPreserveList, AsmUsed, Mangler); + + GlobalVariable *LLVMCompilerUsed = + mergedModule->getGlobalVariable("llvm.compiler.used"); + findUsedValues(LLVMCompilerUsed, AsmUsed); + if (LLVMCompilerUsed) + LLVMCompilerUsed->eraseFromParent(); + + if (!AsmUsed.empty()) { + llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(Context); + std::vector<Constant*> asmUsed2; + for (SmallPtrSet<GlobalValue*, 16>::const_iterator i = AsmUsed.begin(), + e = AsmUsed.end(); i !=e; ++i) { + GlobalValue *GV = *i; + Constant *c = ConstantExpr::getBitCast(GV, i8PTy); + asmUsed2.push_back(c); + } + + llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, asmUsed2.size()); + LLVMCompilerUsed = + new llvm::GlobalVariable(*mergedModule, ATy, false, + llvm::GlobalValue::AppendingLinkage, + llvm::ConstantArray::get(ATy, asmUsed2), + "llvm.compiler.used"); + + LLVMCompilerUsed->setSection("llvm.metadata"); + } + + passes.add(createInternalizePass(MustPreserveList)); + + // apply scope restrictions + passes.run(*mergedModule); + + ScopeRestrictionsDone = true; +} + +/// Optimize merged modules using various IPO passes +bool LTOCodeGenerator::generateObjectFile(raw_ostream &out, + std::string &errMsg) { + if (!this->determineTarget(errMsg)) + return false; + + Module *mergedModule = Linker.getModule(); + + // Mark which symbols can not be internalized + this->applyScopeRestrictions(); + + // Instantiate the pass manager to organize the passes. + PassManager passes; + + // Start off with a verification pass. + passes.add(createVerifierPass()); + + // Add an appropriate DataLayout instance for this module... + passes.add(new DataLayout(*TargetMach->getDataLayout())); + TargetMach->addAnalysisPasses(passes); + + // Enabling internalize here would use its AllButMain variant. It + // keeps only main if it exists and does nothing for libraries. Instead + // we create the pass ourselves with the symbol list provided by the linker. + if (!DisableOpt) + PassManagerBuilder().populateLTOPassManager(passes, + /*Internalize=*/false, + !DisableInline, + DisableGVNLoadPRE); + + // Make sure everything is still good. + passes.add(createVerifierPass()); + + PassManager codeGenPasses; + + codeGenPasses.add(new DataLayout(*TargetMach->getDataLayout())); + TargetMach->addAnalysisPasses(codeGenPasses); + + formatted_raw_ostream Out(out); + + // If the bitcode files contain ARC code and were compiled with optimization, + // the ObjCARCContractPass must be run, so do it unconditionally here. + codeGenPasses.add(createObjCARCContractPass()); + + if (TargetMach->addPassesToEmitFile(codeGenPasses, Out, + TargetMachine::CGFT_ObjectFile)) { + errMsg = "target file type not supported"; + return false; + } + + // Run our queue of passes all at once now, efficiently. + passes.run(*mergedModule); + + // Run the code generator, and write assembly file + codeGenPasses.run(*mergedModule); + + return true; +} + +/// setCodeGenDebugOptions - Set codegen debugging options to aid in debugging +/// LTO problems. +void LTOCodeGenerator::setCodeGenDebugOptions(const char *options) { + for (std::pair<StringRef, StringRef> o = getToken(options); + !o.first.empty(); o = getToken(o.second)) { + // ParseCommandLineOptions() expects argv[0] to be program name. Lazily add + // that. + if (CodegenOptions.empty()) + CodegenOptions.push_back(strdup("libLLVMLTO")); + CodegenOptions.push_back(strdup(o.first.str().c_str())); + } +} |