Move LTO support library to a component, allowing it to be tested
more reliably across platforms. Patch by Tom Roeder!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191343 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/LTO/LTOCodeGenerator.cpp b/lib/LTO/LTOCodeGenerator.cpp
new file mode 100644
index 0000000..22e9754
--- /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()));
+ }
+}