lib/CodeGen/LLVMTargetMachine.cpp

   1 //===-- LLVMTargetMachine.cpp - Implement the LLVMTargetMachine class -----===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements the LLVMTargetMachine class.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/Analysis/Passes.h"
  14 #include "llvm/CodeGen/AsmPrinter.h"
  15 #include "llvm/CodeGen/BasicTTIImpl.h"
  16 #include "llvm/CodeGen/MachineModuleInfo.h"
  17 #include "llvm/CodeGen/Passes.h"
  18 #include "llvm/CodeGen/TargetPassConfig.h"
  19 #include "llvm/IR/LegacyPassManager.h"
  20 #include "llvm/MC/MCAsmBackend.h"
  21 #include "llvm/MC/MCAsmInfo.h"
  22 #include "llvm/MC/MCCodeEmitter.h"
  23 #include "llvm/MC/MCContext.h"
  24 #include "llvm/MC/MCInstrInfo.h"
  25 #include "llvm/MC/MCObjectWriter.h"
  26 #include "llvm/MC/MCStreamer.h"
  27 #include "llvm/MC/MCSubtargetInfo.h"
  28 #include "llvm/Support/CommandLine.h"
  29 #include "llvm/Support/ErrorHandling.h"
  30 #include "llvm/Support/FormattedStream.h"
  31 #include "llvm/Support/TargetRegistry.h"
  32 #include "llvm/Target/TargetLoweringObjectFile.h"
  33 #include "llvm/Target/TargetMachine.h"
  34 #include "llvm/Target/TargetOptions.h"
  35 using namespace llvm;
  36
  37 static cl::opt<bool> EnableTrapUnreachable("trap-unreachable",
  38   cl::Hidden, cl::ZeroOrMore, cl::init(false),
  39   cl::desc("Enable generating trap for unreachable"));
  40
  41 void LLVMTargetMachine::initAsmInfo() {
  42   MRI.reset(TheTarget.createMCRegInfo(getTargetTriple().str()));
  43   MII.reset(TheTarget.createMCInstrInfo());
  44   // FIXME: Having an MCSubtargetInfo on the target machine is a hack due
  45   // to some backends having subtarget feature dependent module level
  46   // code generation. This is similar to the hack in the AsmPrinter for
  47   // module level assembly etc.
  48   STI.reset(TheTarget.createMCSubtargetInfo(
  49       getTargetTriple().str(), getTargetCPU(), getTargetFeatureString()));
  50
  51   MCAsmInfo *TmpAsmInfo =
  52       TheTarget.createMCAsmInfo(*MRI, getTargetTriple().str());
  53   // TargetSelect.h moved to a different directory between LLVM 2.9 and 3.0,
  54   // and if the old one gets included then MCAsmInfo will be NULL and
  55   // we'll crash later.
  56   // Provide the user with a useful error message about what's wrong.
  57   assert(TmpAsmInfo && "MCAsmInfo not initialized. "
  58          "Make sure you include the correct TargetSelect.h"
  59          "and that InitializeAllTargetMCs() is being invoked!");
  60
  61   if (Options.DisableIntegratedAS)
  62     TmpAsmInfo->setUseIntegratedAssembler(false);
  63
  64   TmpAsmInfo->setPreserveAsmComments(Options.MCOptions.PreserveAsmComments);
  65
  66   TmpAsmInfo->setCompressDebugSections(Options.CompressDebugSections);
  67
  68   TmpAsmInfo->setRelaxELFRelocations(Options.RelaxELFRelocations);
  69
  70   if (Options.ExceptionModel != ExceptionHandling::None)
  71     TmpAsmInfo->setExceptionsType(Options.ExceptionModel);
  72
  73   AsmInfo.reset(TmpAsmInfo);
  74 }
  75
  76 LLVMTargetMachine::LLVMTargetMachine(const Target &T,
  77                                      StringRef DataLayoutString,
  78                                      const Triple &TT, StringRef CPU,
  79                                      StringRef FS, const TargetOptions &Options,
  80                                      Reloc::Model RM, CodeModel::Model CM,
  81                                      CodeGenOpt::Level OL)
  82     : TargetMachine(T, DataLayoutString, TT, CPU, FS, Options) {
  83   this->RM = RM;
  84   this->CMModel = CM;
  85   this->OptLevel = OL;
  86
  87   if (EnableTrapUnreachable)
  88     this->Options.TrapUnreachable = true;
  89 }
  90
  91 TargetTransformInfo
  92 LLVMTargetMachine::getTargetTransformInfo(const Function &F) {
  93   return TargetTransformInfo(BasicTTIImpl(this, F));
  94 }
  95
  96 /// addPassesToX helper drives creation and initialization of TargetPassConfig.
  97 static TargetPassConfig *
  98 addPassesToGenerateCode(LLVMTargetMachine &TM, PassManagerBase &PM,
  99                         bool DisableVerify, MachineModuleInfo &MMI) {
 100   // Targets may override createPassConfig to provide a target-specific
 101   // subclass.
 102   TargetPassConfig *PassConfig = TM.createPassConfig(PM);
 103   // Set PassConfig options provided by TargetMachine.
 104   PassConfig->setDisableVerify(DisableVerify);
 105   PM.add(PassConfig);
 106   PM.add(&MMI);
 107
 108   if (PassConfig->addISelPasses())
 109     return nullptr;
 110   PassConfig->addMachinePasses();
 111   PassConfig->setInitialized();
 112   return PassConfig;
 113 }
 114
 115 bool LLVMTargetMachine::addAsmPrinter(PassManagerBase &PM,
 116                                       raw_pwrite_stream &Out,
 117                                       raw_pwrite_stream *DwoOut,
 118                                       CodeGenFileType FileType,
 119                                       MCContext &Context) {
 120   if (Options.MCOptions.MCSaveTempLabels)
 121     Context.setAllowTemporaryLabels(false);
 122
 123   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
 124   const MCAsmInfo &MAI = *getMCAsmInfo();
 125   const MCRegisterInfo &MRI = *getMCRegisterInfo();
 126   const MCInstrInfo &MII = *getMCInstrInfo();
 127
 128   std::unique_ptr<MCStreamer> AsmStreamer;
 129
 130   switch (FileType) {
 131   case CGFT_AssemblyFile: {
 132     MCInstPrinter *InstPrinter = getTarget().createMCInstPrinter(
 133         getTargetTriple(), MAI.getAssemblerDialect(), MAI, MII, MRI);
 134
 135     // Create a code emitter if asked to show the encoding.
 136     std::unique_ptr<MCCodeEmitter> MCE;
 137     if (Options.MCOptions.ShowMCEncoding)
 138       MCE.reset(getTarget().createMCCodeEmitter(MII, MRI, Context));
 139
 140     std::unique_ptr<MCAsmBackend> MAB(
 141         getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions));
 142     auto FOut = llvm::make_unique<formatted_raw_ostream>(Out);
 143     MCStreamer *S = getTarget().createAsmStreamer(
 144         Context, std::move(FOut), Options.MCOptions.AsmVerbose,
 145         Options.MCOptions.MCUseDwarfDirectory, InstPrinter, std::move(MCE),
 146         std::move(MAB), Options.MCOptions.ShowMCInst);
 147     AsmStreamer.reset(S);
 148     break;
 149   }
 150   case CGFT_ObjectFile: {
 151     // Create the code emitter for the target if it exists.  If not, .o file
 152     // emission fails.
 153     MCCodeEmitter *MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
 154     MCAsmBackend *MAB =
 155         getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions);
 156     if (!MCE || !MAB)
 157       return true;
 158
 159     // Don't waste memory on names of temp labels.
 160     Context.setUseNamesOnTempLabels(false);
 161
 162     Triple T(getTargetTriple().str());
 163     AsmStreamer.reset(getTarget().createMCObjectStreamer(
 164         T, Context, std::unique_ptr<MCAsmBackend>(MAB),
 165         DwoOut ? MAB->createDwoObjectWriter(Out, *DwoOut)
 166                : MAB->createObjectWriter(Out),
 167         std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
 168         Options.MCOptions.MCIncrementalLinkerCompatible,
 169         /*DWARFMustBeAtTheEnd*/ true));
 170     break;
 171   }
 172   case CGFT_Null:
 173     // The Null output is intended for use for performance analysis and testing,
 174     // not real users.
 175     AsmStreamer.reset(getTarget().createNullStreamer(Context));
 176     break;
 177   }
 178
 179   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
 180   FunctionPass *Printer =
 181       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
 182   if (!Printer)
 183     return true;
 184
 185   PM.add(Printer);
 186   return false;
 187 }
 188
 189 bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
 190                                             raw_pwrite_stream &Out,
 191                                             raw_pwrite_stream *DwoOut,
 192                                             CodeGenFileType FileType,
 193                                             bool DisableVerify,
 194                                             MachineModuleInfo *MMI) {
 195   // Add common CodeGen passes.
 196   if (!MMI)
 197     MMI = new MachineModuleInfo(this);
 198   TargetPassConfig *PassConfig =
 199       addPassesToGenerateCode(*this, PM, DisableVerify, *MMI);
 200   if (!PassConfig)
 201     return true;
 202
 203   if (!TargetPassConfig::willCompleteCodeGenPipeline()) {
 204     if (this->getTargetTriple().isOSAIX()) {
 205       // On AIX, we might manifest MCSymbols during SDAG lowering. For MIR
 206       // testing to be meaningful, we need to ensure that the symbols created
 207       // are MCSymbolXCOFF variants, which requires that
 208       // the TargetLoweringObjectFile instance has been initialized.
 209       MCContext &Ctx = MMI->getContext();
 210       const_cast<TargetLoweringObjectFile &>(*this->getObjFileLowering())
 211           .Initialize(Ctx, *this);
 212     }
 213     PM.add(createPrintMIRPass(Out));
 214   } else if (addAsmPrinter(PM, Out, DwoOut, FileType, MMI->getContext()))
 215     return true;
 216
 217   PM.add(createFreeMachineFunctionPass());
 218   return false;
 219 }
 220
 221 /// addPassesToEmitMC - Add passes to the specified pass manager to get
 222 /// machine code emitted with the MCJIT. This method returns true if machine
 223 /// code is not supported. It fills the MCContext Ctx pointer which can be
 224 /// used to build custom MCStreamer.
 225 ///
 226 bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
 227                                           raw_pwrite_stream &Out,
 228                                           bool DisableVerify) {
 229   // Add common CodeGen passes.
 230   MachineModuleInfo *MMI = new MachineModuleInfo(this);
 231   TargetPassConfig *PassConfig =
 232       addPassesToGenerateCode(*this, PM, DisableVerify, *MMI);
 233   if (!PassConfig)
 234     return true;
 235   assert(TargetPassConfig::willCompleteCodeGenPipeline() &&
 236          "Cannot emit MC with limited codegen pipeline");
 237
 238   Ctx = &MMI->getContext();
 239   if (Options.MCOptions.MCSaveTempLabels)
 240     Ctx->setAllowTemporaryLabels(false);
 241
 242   // Create the code emitter for the target if it exists.  If not, .o file
 243   // emission fails.
 244   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
 245   const MCRegisterInfo &MRI = *getMCRegisterInfo();
 246   MCCodeEmitter *MCE =
 247       getTarget().createMCCodeEmitter(*getMCInstrInfo(), MRI, *Ctx);
 248   MCAsmBackend *MAB =
 249       getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions);
 250   if (!MCE || !MAB)
 251     return true;
 252
 253   const Triple &T = getTargetTriple();
 254   std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
 255       T, *Ctx, std::unique_ptr<MCAsmBackend>(MAB), MAB->createObjectWriter(Out),
 256       std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
 257       Options.MCOptions.MCIncrementalLinkerCompatible,
 258       /*DWARFMustBeAtTheEnd*/ true));
 259
 260   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
 261   FunctionPass *Printer =
 262       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
 263   if (!Printer)
 264     return true;
 265
 266   PM.add(Printer);
 267   PM.add(createFreeMachineFunctionPass());
 268
 269   return false; // success!
 270 }