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