C++ TargetMachine类代码示例

/// Find the target operand flags that describe how a global value should be
/// referenced for the current subtarget.
unsigned char
AArch64Subtarget::ClassifyGlobalReference(const GlobalValue *GV,
                                          const TargetMachine &TM) const {
  // MachO large model always goes via a GOT, simply to get a single 8-byte
  // absolute relocation on all global addresses.
  if (TM.getCodeModel() == CodeModel::Large && isTargetMachO())
    return AArch64II::MO_GOT;

  if (!TM.shouldAssumeDSOLocal(*GV->getParent(), GV))
    return AArch64II::MO_GOT;

  // The small code mode's direct accesses use ADRP, which cannot necessarily
  // produce the value 0 (if the code is above 4GB).
  if (TM.getCodeModel() == CodeModel::Small && GV->hasExternalWeakLinkage())
    return AArch64II::MO_GOT;

  return AArch64II::MO_NO_FLAG;
}

void TargetLoweringObjectFileMachO::getNameWithPrefix(
    SmallVectorImpl<char> &OutName, const GlobalValue *GV, Mangler &Mang,
    const TargetMachine &TM) const {
  SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
  const MCSection *TheSection = SectionForGlobal(GV, GVKind, Mang, TM);
  bool CannotUsePrivateLabel =
      !canUsePrivateLabel(*TM.getMCAsmInfo(), *TheSection);
  Mang.getNameWithPrefix(OutName, GV, CannotUsePrivateLabel);
}

MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
                                 unsigned FunctionNum, MachineModuleInfo &mmi,
                                 GCModuleInfo* gmi)
  : Fn(F), Target(TM), Ctx(mmi.getContext()), MMI(mmi), GMI(gmi) {
  if (TM.getRegisterInfo())
    RegInfo = new (Allocator) MachineRegisterInfo(*TM.getRegisterInfo());
  else
    RegInfo = 0;
  MFInfo = 0;
  FrameInfo = new (Allocator) MachineFrameInfo(*TM.getFrameLowering());
  if (Fn->hasFnAttr(Attribute::StackAlignment))
    FrameInfo->setMaxAlignment(Attribute::getStackAlignmentFromAttrs(
        Fn->getAttributes().getFnAttributes()));
  ConstantPool = new (Allocator) MachineConstantPool(TM.getTargetData());
  Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
  FunctionNumber = FunctionNum;
  JumpTableInfo = 0;
}

static void runLTOPasses(Module &M, TargetMachine &TM) {
  if (const DataLayout *DL = TM.getDataLayout())
    M.setDataLayout(*DL);

  legacy::PassManager passes;
  passes.add(createTargetTransformInfoWrapperPass(TM.getTargetIRAnalysis()));

  PassManagerBuilder PMB;
  PMB.LibraryInfo = new TargetLibraryInfoImpl(Triple(TM.getTargetTriple()));
  PMB.Inliner = createFunctionInliningPass();
  PMB.VerifyInput = true;
  PMB.VerifyOutput = true;
  PMB.LoopVectorize = true;
  PMB.SLPVectorize = true;
  PMB.OptLevel = options::OptLevel;
  PMB.populateLTOPassManager(passes);
  passes.run(M);
}

AArch64Subtarget::AArch64Subtarget(const Triple &TT, const std::string &CPU,
                                   const std::string &FS,
                                   const TargetMachine &TM, bool LittleEndian)
    : AArch64GenSubtargetInfo(TT, CPU, FS), ARMProcFamily(Others),
      HasV8_1aOps(false), HasFPARMv8(false), HasNEON(false), HasCrypto(false),
      HasCRC(false), HasZeroCycleRegMove(false), HasZeroCycleZeroing(false),
      IsLittle(LittleEndian), CPUString(CPU), TargetTriple(TT), FrameLowering(),
      InstrInfo(initializeSubtargetDependencies(FS)),
      TSInfo(TM.getDataLayout()), TLInfo(TM, *this) {}

MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
                                 unsigned FunctionNum, MachineModuleInfo &mmi)
    : Fn(F), Target(TM), STI(TM.getSubtargetImpl(*F)), Ctx(mmi.getContext()),
      MMI(mmi) {
  if (STI->getRegisterInfo())
    RegInfo = new (Allocator) MachineRegisterInfo(this);
  else
    RegInfo = nullptr;

  MFInfo = nullptr;
  FrameInfo = new (Allocator)
      MachineFrameInfo(STI->getFrameLowering()->getStackAlignment(),
                       STI->getFrameLowering()->isStackRealignable(),
                       !F->hasFnAttribute("no-realign-stack"));

  if (Fn->hasFnAttribute(Attribute::StackAlignment))
    FrameInfo->ensureMaxAlignment(Fn->getFnStackAlignment());

  ConstantPool = new (Allocator) MachineConstantPool(getDataLayout());
  Alignment = STI->getTargetLowering()->getMinFunctionAlignment();

  // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
  // FIXME: Use Function::optForSize().
  if (!Fn->hasFnAttribute(Attribute::OptimizeForSize))
    Alignment = std::max(Alignment,
                         STI->getTargetLowering()->getPrefFunctionAlignment());

  if (AlignAllFunctions)
    Alignment = AlignAllFunctions;

  FunctionNumber = FunctionNum;
  JumpTableInfo = nullptr;

  if (isFuncletEHPersonality(classifyEHPersonality(
          F->hasPersonalityFn() ? F->getPersonalityFn() : nullptr))) {
    WinEHInfo = new (Allocator) WinEHFuncInfo();
  }

  assert(TM.isCompatibleDataLayout(getDataLayout()) &&
         "Can't create a MachineFunction using a Module with a "
         "Target-incompatible DataLayout attached\n");

  PSVManager = llvm::make_unique<PseudoSourceValueManager>();
}

bool RaiseAsmPass::runOnModule(Module &M) {
  bool changed = false;

  std::string Err;
#if LLVM_VERSION_CODE >= LLVM_VERSION(3, 1)
  std::string HostTriple = llvm::sys::getDefaultTargetTriple();
#else
  std::string HostTriple = llvm::sys::getHostTriple();
#endif
  const Target *NativeTarget = TargetRegistry::lookupTarget(HostTriple, Err);

  TargetMachine * TM = 0;
  if (NativeTarget == 0) {
    klee_warning("Warning: unable to select native target: %s", Err.c_str());
    TLI = 0;
  } else {
#if LLVM_VERSION_CODE >= LLVM_VERSION(3, 1)
    TM = NativeTarget->createTargetMachine(HostTriple, "", "",
                                                          TargetOptions());
#elif LLVM_VERSION_CODE >= LLVM_VERSION(3, 0)
    TM = NativeTarget->createTargetMachine(HostTriple, "", "");
#else
    TM = NativeTarget->createTargetMachine(HostTriple, "");
#endif
    TLI = TM->getTargetLowering();

    triple = llvm::Triple(HostTriple);
  }
  
  for (Module::iterator fi = M.begin(), fe = M.end(); fi != fe; ++fi) {
    for (Function::iterator bi = fi->begin(), be = fi->end(); bi != be; ++bi) {
      for (BasicBlock::iterator ii = bi->begin(), ie = bi->end(); ii != ie;) {
        Instruction *i = ii;
        ++ii;  
        changed |= runOnInstruction(M, i);
      }
    }
  }

  if (TM)
    delete TM;

  return changed;
}

static void runLTOPasses(Module &M, TargetMachine &TM) {
  PassManager passes;
  PassManagerBuilder PMB;
  PMB.LibraryInfo = new TargetLibraryInfo(Triple(TM.getTargetTriple()));
  PMB.Inliner = createFunctionInliningPass();
  PMB.VerifyInput = true;
  PMB.VerifyOutput = true;
  PMB.populateLTOPassManager(passes, &TM);
  passes.run(M);
}

static void runLTOPasses(Module &M, TargetMachine &TM) {
  M.setDataLayout(TM.createDataLayout());

  legacy::PassManager passes;
  passes.add(createTargetTransformInfoWrapperPass(TM.getTargetIRAnalysis()));

  PassManagerBuilder PMB;
  PMB.LibraryInfo = new TargetLibraryInfoImpl(Triple(TM.getTargetTriple()));
  PMB.Inliner = createFunctionInliningPass();
  // Unconditionally verify input since it is not verified before this
  // point and has unknown origin.
  PMB.VerifyInput = true;
  PMB.VerifyOutput = !options::DisableVerify;
  PMB.LoopVectorize = true;
  PMB.SLPVectorize = true;
  PMB.OptLevel = options::OptLevel;
  PMB.populateLTOPassManager(passes);
  passes.run(M);
}

extern "C" bool
LLVMRustWriteOutputFile(LLVMPassManagerRef PMR,
                        LLVMModuleRef M,
                        const char *triple,
                        const char *path,
                        TargetMachine::CodeGenFileType FileType,
                        CodeGenOpt::Level OptLevel,
			bool EnableSegmentedStacks) {

  LLVMRustInitializeTargets();

  TargetOptions Options;
  Options.NoFramePointerElim = true;
  Options.EnableSegmentedStacks = EnableSegmentedStacks;

  std::string Err;
  const Target *TheTarget = TargetRegistry::lookupTarget(triple, Err);
  std::string FeaturesStr;
  std::string Trip(triple);
  std::string CPUStr("generic");
  TargetMachine *Target =
    TheTarget->createTargetMachine(Trip, CPUStr, FeaturesStr,
				   Options, Reloc::PIC_,
				   CodeModel::Default, OptLevel);
  bool NoVerify = false;
  PassManager *PM = unwrap<PassManager>(PMR);
  std::string ErrorInfo;
  raw_fd_ostream OS(path, ErrorInfo,
                    raw_fd_ostream::F_Binary);
  if (ErrorInfo != "") {
    LLVMRustError = ErrorInfo.c_str();
    return false;
  }
  formatted_raw_ostream FOS(OS);

  bool foo = Target->addPassesToEmitFile(*PM, FOS, FileType, NoVerify);
  assert(!foo);
  (void)foo;
  PM->run(*unwrap(M));
  delete Target;
  return true;
}

std::unique_ptr<llvm::SmallVectorImpl<char>>
getBPFObjectFromModule(llvm::Module *Module)
{
	using namespace llvm;

	std::string TargetTriple("bpf-pc-linux");
	std::string Error;
	const Target* Target = TargetRegistry::lookupTarget(TargetTriple, Error);
	if (!Target) {
		llvm::errs() << Error;
		return std::unique_ptr<llvm::SmallVectorImpl<char>>(nullptr);
	}

	llvm::TargetOptions Opt;
	TargetMachine *TargetMachine =
		Target->createTargetMachine(TargetTriple,
					    "generic", "",
					    Opt, Reloc::Static);

	Module->setDataLayout(TargetMachine->createDataLayout());
	Module->setTargetTriple(TargetTriple);

	std::unique_ptr<SmallVectorImpl<char>> Buffer(new SmallVector<char, 0>());
	raw_svector_ostream ostream(*Buffer);

	legacy::PassManager PM;
	bool NotAdded;
#if CLANG_VERSION_MAJOR < 7
	NotAdded = TargetMachine->addPassesToEmitFile(PM, ostream,
						      TargetMachine::CGFT_ObjectFile);
#else
	NotAdded = TargetMachine->addPassesToEmitFile(PM, ostream, nullptr,
						      TargetMachine::CGFT_ObjectFile);
#endif
	if (NotAdded) {
		llvm::errs() << "TargetMachine can't emit a file of this type\n";
		return std::unique_ptr<llvm::SmallVectorImpl<char>>(nullptr);
	}
	PM.run(*Module);

	return Buffer;
}

/// hasLazyResolverStub - Return true if accesses to the specified global have
/// to go through a dyld lazy resolution stub.  This means that an extra load
/// is required to get the address of the global.
bool PPCSubtarget::hasLazyResolverStub(const GlobalValue *GV,
                                       const TargetMachine &TM) const {
  // We never have stubs if HasLazyResolverStubs=false or if in static mode.
  if (!HasLazyResolverStubs || TM.getRelocationModel() == Reloc::Static)
    return false;
  bool isDecl = GV->isDeclaration();
  if (GV->hasHiddenVisibility() && !isDecl && !GV->hasCommonLinkage())
    return false;
  return GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
         GV->hasCommonLinkage() || isDecl;
}

MachineFunction::MachineFunction(Function *F, const TargetMachine &TM,
                                 unsigned FunctionNum, MCContext &ctx)
  : Fn(F), Target(TM), Ctx(ctx) {
  if (TM.getRegisterInfo())
    RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
                  MachineRegisterInfo(*TM.getRegisterInfo());
  else
    RegInfo = 0;
  MFInfo = 0;
  FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
                  MachineFrameInfo(*TM.getFrameInfo());
  if (Fn->hasFnAttr(Attribute::StackAlignment))
    FrameInfo->setMaxAlignment(Attribute::getStackAlignmentFromAttrs(
        Fn->getAttributes().getFnAttributes()));
  ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
                     MachineConstantPool(TM.getTargetData());
  Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
  FunctionNumber = FunctionNum;
  JumpTableInfo = 0;
}

/// create - Create an return a new JIT compiler if there is one available
/// for the current target.  Otherwise, return null.
///
ExecutionEngine *JIT::create(ModuleProvider *MP, IntrinsicLowering *IL) {
  if (MArch == 0) {
    std::string Error;
    MArch = TargetMachineRegistry::getClosestTargetForJIT(Error);
    if (MArch == 0) return 0;
  } else if (MArch->JITMatchQualityFn() == 0) {
    std::cerr << "WARNING: This target JIT is not designed for the host you are"
              << " running.  If bad things happen, please choose a different "
              << "-march switch.\n";
  }

  // Allocate a target...
  TargetMachine *Target = MArch->CtorFn(*MP->getModule(), IL);
  assert(Target && "Could not allocate target machine!");

  // If the target supports JIT code generation, return a new JIT now.
  if (TargetJITInfo *TJ = Target->getJITInfo())
    return new JIT(MP, *Target, *TJ);
  return 0;
}

/// ClassifyGlobalReference - Find the target operand flags that describe
/// how a global value should be referenced for the current subtarget.
unsigned char
ARM64Subtarget::ClassifyGlobalReference(const GlobalValue *GV,
                                        const TargetMachine &TM) const {

  // Determine whether this is a reference to a definition or a declaration.
  // Materializable GVs (in JIT lazy compilation mode) do not require an extra
  // load from stub.
  bool isDecl = GV->hasAvailableExternallyLinkage();
  if (GV->isDeclaration() && !GV->isMaterializable())
    isDecl = true;

  // MachO large model always goes via a GOT, simply to get a single 8-byte
  // absolute relocation on all global addresses.
  if (TM.getCodeModel() == CodeModel::Large && isTargetMachO())
    return ARM64II::MO_GOT;

  // The small code mode's direct accesses use ADRP, which cannot necessarily
  // produce the value 0 (if the code is above 4GB). Therefore they must use the
  // GOT.
  if (TM.getCodeModel() == CodeModel::Small && GV->isWeakForLinker() && isDecl)
    return ARM64II::MO_GOT;

  // If symbol visibility is hidden, the extra load is not needed if
  // the symbol is definitely defined in the current translation unit.

  // The handling of non-hidden symbols in PIC mode is rather target-dependent:
  //   + On MachO, if the symbol is defined in this module the GOT can be
  //     skipped.
  //   + On ELF, the R_AARCH64_COPY relocation means that even symbols actually
  //     defined could end up in unexpected places. Use a GOT.
  if (TM.getRelocationModel() != Reloc::Static && GV->hasDefaultVisibility()) {
    if (isTargetMachO())
      return (isDecl || GV->isWeakForLinker()) ? ARM64II::MO_GOT
                                               : ARM64II::MO_NO_FLAG;
    else
      // No need to go through the GOT for local symbols on ELF.
      return GV->hasLocalLinkage() ? ARM64II::MO_NO_FLAG : ARM64II::MO_GOT;
  }

  return ARM64II::MO_NO_FLAG;
}