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//===-- LLVMTargetMachine.cpp - Implement the LLVMTargetMachine class -----===//
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// The LLVM Compiler Infrastructure
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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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// This file implements the LLVMTargetMachine class.
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//===----------------------------------------------------------------------===//
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#include "llvm/Target/TargetMachine.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/CodeGen/AsmPrinter.h"
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#include "llvm/CodeGen/MachineFunctionAnalysis.h"
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#include "llvm/CodeGen/MachineModuleInfo.h"
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#include "llvm/CodeGen/GCStrategy.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/MC/MCAsmInfo.h"
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#include "llvm/MC/MCStreamer.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Target/TargetRegistry.h"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/ADT/OwningPtr.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/FormattedStream.h"
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static cl::opt<bool> DisablePostRA("disable-post-ra", cl::Hidden,
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cl::desc("Disable Post Regalloc"));
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static cl::opt<bool> DisableBranchFold("disable-branch-fold", cl::Hidden,
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cl::desc("Disable branch folding"));
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static cl::opt<bool> DisableTailDuplicate("disable-tail-duplicate", cl::Hidden,
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cl::desc("Disable tail duplication"));
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static cl::opt<bool> DisableEarlyTailDup("disable-early-taildup", cl::Hidden,
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cl::desc("Disable pre-register allocation tail duplication"));
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static cl::opt<bool> DisableCodePlace("disable-code-place", cl::Hidden,
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cl::desc("Disable code placement"));
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static cl::opt<bool> DisableSSC("disable-ssc", cl::Hidden,
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cl::desc("Disable Stack Slot Coloring"));
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static cl::opt<bool> DisableMachineLICM("disable-machine-licm", cl::Hidden,
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cl::desc("Disable Machine LICM"));
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static cl::opt<bool> DisablePostRAMachineLICM("disable-postra-machine-licm",
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cl::desc("Disable Machine LICM"));
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static cl::opt<bool> DisableMachineSink("disable-machine-sink", cl::Hidden,
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cl::desc("Disable Machine Sinking"));
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static cl::opt<bool> DisableLSR("disable-lsr", cl::Hidden,
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cl::desc("Disable Loop Strength Reduction Pass"));
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static cl::opt<bool> DisableCGP("disable-cgp", cl::Hidden,
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cl::desc("Disable Codegen Prepare"));
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static cl::opt<bool> PrintLSR("print-lsr-output", cl::Hidden,
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cl::desc("Print LLVM IR produced by the loop-reduce pass"));
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static cl::opt<bool> PrintISelInput("print-isel-input", cl::Hidden,
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cl::desc("Print LLVM IR input to isel pass"));
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static cl::opt<bool> PrintGCInfo("print-gc", cl::Hidden,
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cl::desc("Dump garbage collector data"));
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static cl::opt<bool> ShowMCEncoding("show-mc-encoding", cl::Hidden,
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cl::desc("Show encoding in .s output"));
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static cl::opt<bool> ShowMCInst("show-mc-inst", cl::Hidden,
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cl::desc("Show instruction structure in .s output"));
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static cl::opt<bool> EnableMCLogging("enable-mc-api-logging", cl::Hidden,
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cl::desc("Enable MC API logging"));
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static cl::opt<bool> VerifyMachineCode("verify-machineinstrs", cl::Hidden,
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cl::desc("Verify generated machine code"),
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cl::init(getenv("LLVM_VERIFY_MACHINEINSTRS")!=NULL));
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static cl::opt<cl::boolOrDefault>
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AsmVerbose("asm-verbose", cl::desc("Add comments to directives."),
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cl::init(cl::BOU_UNSET));
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static bool getVerboseAsm() {
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case cl::BOU_UNSET: return TargetMachine::getAsmVerbosityDefault();
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case cl::BOU_TRUE: return true;
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case cl::BOU_FALSE: return false;
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// Enable or disable FastISel. Both options are needed, because
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// FastISel is enabled by default with -fast, and we wish to be
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// able to enable or disable fast-isel independently from -O0.
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static cl::opt<cl::boolOrDefault>
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EnableFastISelOption("fast-isel", cl::Hidden,
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cl::desc("Enable the \"fast\" instruction selector"));
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// Enable or disable an experimental optimization to split GEPs
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// and run a special GVN pass which does not examine loads, in
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// an effort to factor out redundancy implicit in complex GEPs.
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static cl::opt<bool> EnableSplitGEPGVN("split-gep-gvn", cl::Hidden,
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cl::desc("Split GEPs and run no-load GVN"));
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LLVMTargetMachine::LLVMTargetMachine(const Target &T,
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const std::string &Triple)
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: TargetMachine(T), TargetTriple(Triple) {
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AsmInfo = T.createAsmInfo(TargetTriple);
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// Set the default code model for the JIT for a generic target.
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// FIXME: Is small right here? or .is64Bit() ? Large : Small?
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void LLVMTargetMachine::setCodeModelForJIT() {
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setCodeModel(CodeModel::Small);
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// Set the default code model for static compilation for a generic target.
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void LLVMTargetMachine::setCodeModelForStatic() {
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setCodeModel(CodeModel::Small);
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bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
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formatted_raw_ostream &Out,
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CodeGenFileType FileType,
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CodeGenOpt::Level OptLevel,
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bool DisableVerify) {
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// Add common CodeGen passes.
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MCContext *Context = 0;
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if (addCommonCodeGenPasses(PM, OptLevel, DisableVerify, Context))
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assert(Context != 0 && "Failed to get MCContext");
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const MCAsmInfo &MAI = *getMCAsmInfo();
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OwningPtr<MCStreamer> AsmStreamer;
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default: return true;
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case CGFT_AssemblyFile: {
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MCInstPrinter *InstPrinter =
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getTarget().createMCInstPrinter(MAI.getAssemblerDialect(), MAI);
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// Create a code emitter if asked to show the encoding.
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MCCodeEmitter *MCE = 0;
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MCE = getTarget().createCodeEmitter(*this, *Context);
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AsmStreamer.reset(createAsmStreamer(*Context, Out,
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getTargetData()->isLittleEndian(),
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getVerboseAsm(), InstPrinter,
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case CGFT_ObjectFile: {
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// Create the code emitter for the target if it exists. If not, .o file
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MCCodeEmitter *MCE = getTarget().createCodeEmitter(*this, *Context);
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TargetAsmBackend *TAB = getTarget().createAsmBackend(TargetTriple);
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if (MCE == 0 || TAB == 0)
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AsmStreamer.reset(getTarget().createObjectStreamer(TargetTriple, *Context,
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// The Null output is intended for use for performance analysis and testing,
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AsmStreamer.reset(createNullStreamer(*Context));
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AsmStreamer.reset(createLoggingStreamer(AsmStreamer.take(), errs()));
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// Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
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FunctionPass *Printer = getTarget().createAsmPrinter(*this, *AsmStreamer);
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// If successful, createAsmPrinter took ownership of AsmStreamer.
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// Make sure the code model is set.
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setCodeModelForStatic();
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PM.add(createGCInfoDeleter());
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/// addPassesToEmitMachineCode - Add passes to the specified pass manager to
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/// get machine code emitted. This uses a JITCodeEmitter object to handle
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/// actually outputting the machine code and resolving things like the address
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/// of functions. This method should returns true if machine code emission is
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bool LLVMTargetMachine::addPassesToEmitMachineCode(PassManagerBase &PM,
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CodeGenOpt::Level OptLevel,
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bool DisableVerify) {
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// Make sure the code model is set.
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setCodeModelForJIT();
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// Add common CodeGen passes.
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if (addCommonCodeGenPasses(PM, OptLevel, DisableVerify, Ctx))
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addCodeEmitter(PM, OptLevel, JCE);
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PM.add(createGCInfoDeleter());
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return false; // success!
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/// addPassesToEmitMC - Add passes to the specified pass manager to get
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/// machine code emitted with the MCJIT. This method returns true if machine
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/// code is not supported. It fills the MCContext Ctx pointer which can be
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/// used to build custom MCStreamer.
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bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM,
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CodeGenOpt::Level OptLevel,
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bool DisableVerify) {
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// Add common CodeGen passes.
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if (addCommonCodeGenPasses(PM, OptLevel, DisableVerify, Ctx))
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// Make sure the code model is set.
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setCodeModelForJIT();
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return false; // success!
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static void printNoVerify(PassManagerBase &PM, const char *Banner) {
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if (PrintMachineCode)
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PM.add(createMachineFunctionPrinterPass(dbgs(), Banner));
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static void printAndVerify(PassManagerBase &PM,
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const char *Banner) {
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if (PrintMachineCode)
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PM.add(createMachineFunctionPrinterPass(dbgs(), Banner));
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if (VerifyMachineCode)
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PM.add(createMachineVerifierPass());
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/// addCommonCodeGenPasses - Add standard LLVM codegen passes used for both
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/// emitting to assembly files or machine code output.
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bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM,
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CodeGenOpt::Level OptLevel,
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MCContext *&OutContext) {
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// Standard LLVM-Level Passes.
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// Before running any passes, run the verifier to determine if the input
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// coming from the front-end and/or optimizer is valid.
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PM.add(createVerifierPass());
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// Optionally, tun split-GEPs and no-load GVN.
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if (EnableSplitGEPGVN) {
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PM.add(createGEPSplitterPass());
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PM.add(createGVNPass(/*NoLoads=*/true));
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// Run loop strength reduction before anything else.
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if (OptLevel != CodeGenOpt::None && !DisableLSR) {
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PM.add(createLoopStrengthReducePass(getTargetLowering()));
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PM.add(createPrintFunctionPass("\n\n*** Code after LSR ***\n", &dbgs()));
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PM.add(createGCLoweringPass());
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// Make sure that no unreachable blocks are instruction selected.
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PM.add(createUnreachableBlockEliminationPass());
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// Turn exception handling constructs into something the code generators can
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switch (getMCAsmInfo()->getExceptionHandlingType()) {
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case ExceptionHandling::SjLj:
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// SjLj piggy-backs on dwarf for this bit. The cleanups done apply to both
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// Dwarf EH prepare needs to be run after SjLj prepare. Otherwise,
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// catch info can get misplaced when a selector ends up more than one block
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// removed from the parent invoke(s). This could happen when a landing
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// pad is shared by multiple invokes and is also a target of a normal
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// edge from elsewhere.
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PM.add(createSjLjEHPass(getTargetLowering()));
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case ExceptionHandling::Dwarf:
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PM.add(createDwarfEHPass(this));
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case ExceptionHandling::None:
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PM.add(createLowerInvokePass(getTargetLowering()));
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// The lower invoke pass may create unreachable code. Remove it.
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PM.add(createUnreachableBlockEliminationPass());
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if (OptLevel != CodeGenOpt::None && !DisableCGP)
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PM.add(createCodeGenPreparePass(getTargetLowering()));
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PM.add(createStackProtectorPass(getTargetLowering()));
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addPreISel(PM, OptLevel);
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PM.add(createPrintFunctionPass("\n\n"
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"*** Final LLVM Code input to ISel ***\n",
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// All passes which modify the LLVM IR are now complete; run the verifier
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// to ensure that the IR is valid.
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PM.add(createVerifierPass());
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// Standard Lower-Level Passes.
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// Install a MachineModuleInfo class, which is an immutable pass that holds
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// all the per-module stuff we're generating, including MCContext.
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MachineModuleInfo *MMI = new MachineModuleInfo(*getMCAsmInfo());
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OutContext = &MMI->getContext(); // Return the MCContext specifically by-ref.
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// Set up a MachineFunction for the rest of CodeGen to work on.
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PM.add(new MachineFunctionAnalysis(*this, OptLevel));
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// Enable FastISel with -fast, but allow that to be overridden.
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if (EnableFastISelOption == cl::BOU_TRUE ||
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(OptLevel == CodeGenOpt::None && EnableFastISelOption != cl::BOU_FALSE))
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EnableFastISel = true;
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// Ask the target for an isel.
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if (addInstSelector(PM, OptLevel))
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// Print the instruction selected machine code...
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printAndVerify(PM, "After Instruction Selection");
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// Optimize PHIs before DCE: removing dead PHI cycles may make more
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// instructions dead.
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if (OptLevel != CodeGenOpt::None)
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PM.add(createOptimizePHIsPass());
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// If the target requests it, assign local variables to stack slots relative
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// to one another and simplify frame index references where possible.
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PM.add(createLocalStackSlotAllocationPass());
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if (OptLevel != CodeGenOpt::None) {
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// With optimization, dead code should already be eliminated. However
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// there is one known exception: lowered code for arguments that are only
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// used by tail calls, where the tail calls reuse the incoming stack
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// arguments directly (see t11 in test/CodeGen/X86/sibcall.ll).
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PM.add(createDeadMachineInstructionElimPass());
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printAndVerify(PM, "After codegen DCE pass");
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PM.add(createPeepholeOptimizerPass());
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if (!DisableMachineLICM)
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PM.add(createMachineLICMPass());
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PM.add(createMachineCSEPass());
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if (!DisableMachineSink)
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PM.add(createMachineSinkingPass());
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printAndVerify(PM, "After Machine LICM, CSE and Sinking passes");
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// Pre-ra tail duplication.
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if (OptLevel != CodeGenOpt::None && !DisableEarlyTailDup) {
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PM.add(createTailDuplicatePass(true));
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printAndVerify(PM, "After Pre-RegAlloc TailDuplicate");
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// Run pre-ra passes.
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if (addPreRegAlloc(PM, OptLevel))
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printAndVerify(PM, "After PreRegAlloc passes");
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// Perform register allocation.
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PM.add(createRegisterAllocator(OptLevel));
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printAndVerify(PM, "After Register Allocation");
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// Perform stack slot coloring and post-ra machine LICM.
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if (OptLevel != CodeGenOpt::None) {
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// FIXME: Re-enable coloring with register when it's capable of adding
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PM.add(createStackSlotColoringPass(false));
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// Run post-ra machine LICM to hoist reloads / remats.
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if (!DisablePostRAMachineLICM)
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PM.add(createMachineLICMPass(false));
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printAndVerify(PM, "After StackSlotColoring and postra Machine LICM");
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// Run post-ra passes.
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if (addPostRegAlloc(PM, OptLevel))
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printAndVerify(PM, "After PostRegAlloc passes");
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PM.add(createLowerSubregsPass());
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printAndVerify(PM, "After LowerSubregs");
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// Insert prolog/epilog code. Eliminate abstract frame index references...
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PM.add(createPrologEpilogCodeInserter());
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printAndVerify(PM, "After PrologEpilogCodeInserter");
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// Run pre-sched2 passes.
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if (addPreSched2(PM, OptLevel))
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printAndVerify(PM, "After PreSched2 passes");
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// Second pass scheduler.
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if (OptLevel != CodeGenOpt::None && !DisablePostRA) {
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PM.add(createPostRAScheduler(OptLevel));
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printAndVerify(PM, "After PostRAScheduler");
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// Branch folding must be run after regalloc and prolog/epilog insertion.
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if (OptLevel != CodeGenOpt::None && !DisableBranchFold) {
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PM.add(createBranchFoldingPass(getEnableTailMergeDefault()));
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printNoVerify(PM, "After BranchFolding");
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if (OptLevel != CodeGenOpt::None && !DisableTailDuplicate) {
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PM.add(createTailDuplicatePass(false));
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printNoVerify(PM, "After TailDuplicate");
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PM.add(createGCMachineCodeAnalysisPass());
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PM.add(createGCInfoPrinter(dbgs()));
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if (OptLevel != CodeGenOpt::None && !DisableCodePlace) {
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PM.add(createCodePlacementOptPass());
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printNoVerify(PM, "After CodePlacementOpt");
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if (addPreEmitPass(PM, OptLevel))
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printNoVerify(PM, "After PreEmit passes");