//===-- TargetMachine.cpp - General Target Information ---------------------==// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// // // This file describes the general parts of a Target machine. // //===----------------------------------------------------------------------===// #include "llvm/Target/TargetMachine.h" #include "llvm/Analysis/TargetTransformInfo.h" #include "llvm/IR/Function.h" #include "llvm/IR/GlobalAlias.h" #include "llvm/IR/GlobalValue.h" #include "llvm/IR/GlobalVariable.h" #include "llvm/IR/LegacyPassManager.h" #include "llvm/IR/Mangler.h" #include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/MCContext.h" #include "llvm/MC/MCInstrInfo.h" #include "llvm/MC/MCSectionMachO.h" #include "llvm/MC/MCTargetOptions.h" #include "llvm/MC/SectionKind.h" #include "llvm/Target/TargetLoweringObjectFile.h" using namespace llvm; //--------------------------------------------------------------------------- // TargetMachine Class // TargetMachine::TargetMachine(const Target &T, StringRef DataLayoutString, const Triple &TT, StringRef CPU, StringRef FS, const TargetOptions &Options) : TheTarget(T), DL(DataLayoutString), TargetTriple(TT), TargetCPU(std::string(CPU)), TargetFS(std::string(FS)), AsmInfo(nullptr), MRI(nullptr), MII(nullptr), STI(nullptr), RequireStructuredCFG(false), O0WantsFastISel(false), DefaultOptions(Options), Options(Options) {} TargetMachine::~TargetMachine() = default; bool TargetMachine::isPositionIndependent() const { return getRelocationModel() == Reloc::PIC_; } /// Reset the target options based on the function's attributes. /// setFunctionAttributes should have made the raw attribute value consistent /// with the command line flag if used. // // FIXME: This function needs to go away for a number of reasons: // a) global state on the TargetMachine is terrible in general, // b) these target options should be passed only on the function // and not on the TargetMachine (via TargetOptions) at all. void TargetMachine::resetTargetOptions(const Function &F) const { #define RESET_OPTION(X, Y) \ do { \ Options.X = F.getFnAttribute(Y).getValueAsBool(); \ } while (0) RESET_OPTION(UnsafeFPMath, "unsafe-fp-math"); RESET_OPTION(NoInfsFPMath, "no-infs-fp-math"); RESET_OPTION(NoNaNsFPMath, "no-nans-fp-math"); RESET_OPTION(NoSignedZerosFPMath, "no-signed-zeros-fp-math"); } /// Returns the code generation relocation model. The choices are static, PIC, /// and dynamic-no-pic. Reloc::Model TargetMachine::getRelocationModel() const { return RM; } /// Returns the code model. The choices are small, kernel, medium, large, and /// target default. CodeModel::Model TargetMachine::getCodeModel() const { return CMModel; } /// Get the IR-specified TLS model for Var. static TLSModel::Model getSelectedTLSModel(const GlobalValue *GV) { switch (GV->getThreadLocalMode()) { case GlobalVariable::NotThreadLocal: llvm_unreachable("getSelectedTLSModel for non-TLS variable"); break; case GlobalVariable::GeneralDynamicTLSModel: return TLSModel::GeneralDynamic; case GlobalVariable::LocalDynamicTLSModel: return TLSModel::LocalDynamic; case GlobalVariable::InitialExecTLSModel: return TLSModel::InitialExec; case GlobalVariable::LocalExecTLSModel: return TLSModel::LocalExec; } llvm_unreachable("invalid TLS model"); } bool TargetMachine::shouldAssumeDSOLocal(const Module &M, const GlobalValue *GV) const { const Triple &TT = getTargetTriple(); Reloc::Model RM = getRelocationModel(); // According to the llvm language reference, we should be able to // just return false in here if we have a GV, as we know it is // dso_preemptable. At this point in time, the various IR producers // have not been transitioned to always produce a dso_local when it // is possible to do so. // // As a result we still have some logic in here to improve the quality of the // generated code. if (!GV) return false; // If the IR producer requested that this GV be treated as dso local, obey. if (GV->isDSOLocal()) return true; if (TT.isOSBinFormatCOFF()) { // DLLImport explicitly marks the GV as external. if (GV->hasDLLImportStorageClass()) return false; // On MinGW, variables that haven't been declared with DLLImport may still // end up automatically imported by the linker. To make this feasible, // don't assume the variables to be DSO local unless we actually know // that for sure. This only has to be done for variables; for functions // the linker can insert thunks for calling functions from another DLL. if (TT.isWindowsGNUEnvironment() && GV->isDeclarationForLinker() && isa<GlobalVariable>(GV)) return false; // Don't mark 'extern_weak' symbols as DSO local. If these symbols remain // unresolved in the link, they can be resolved to zero, which is outside // the current DSO. if (GV->hasExternalWeakLinkage()) return false; // Every other GV is local on COFF. return true; } if (TT.isOSBinFormatGOFF()) return true; if (TT.isOSBinFormatMachO()) { if (RM == Reloc::Static) return true; return GV->isStrongDefinitionForLinker(); } assert(TT.isOSBinFormatELF() || TT.isOSBinFormatWasm() || TT.isOSBinFormatXCOFF()); return false; } bool TargetMachine::useEmulatedTLS() const { // Returns Options.EmulatedTLS if the -emulated-tls or -no-emulated-tls // was specified explicitly; otherwise uses target triple to decide default. if (Options.ExplicitEmulatedTLS) return Options.EmulatedTLS; return getTargetTriple().hasDefaultEmulatedTLS(); } TLSModel::Model TargetMachine::getTLSModel(const GlobalValue *GV) const { bool IsPIE = GV->getParent()->getPIELevel() != PIELevel::Default; Reloc::Model RM = getRelocationModel(); bool IsSharedLibrary = RM == Reloc::PIC_ && !IsPIE; bool IsLocal = shouldAssumeDSOLocal(*GV->getParent(), GV); TLSModel::Model Model; if (IsSharedLibrary) { if (IsLocal) Model = TLSModel::LocalDynamic; else Model = TLSModel::GeneralDynamic; } else { if (IsLocal) Model = TLSModel::LocalExec; else Model = TLSModel::InitialExec; } // If the user specified a more specific model, use that. TLSModel::Model SelectedModel = getSelectedTLSModel(GV); if (SelectedModel > Model) return SelectedModel; return Model; } /// Returns the optimization level: None, Less, Default, or Aggressive. CodeGenOpt::Level TargetMachine::getOptLevel() const { return OptLevel; } void TargetMachine::setOptLevel(CodeGenOpt::Level Level) { OptLevel = Level; } TargetTransformInfo TargetMachine::getTargetTransformInfo(const Function &F) { return TargetTransformInfo(F.getParent()->getDataLayout()); } void TargetMachine::getNameWithPrefix(SmallVectorImpl<char> &Name, const GlobalValue *GV, Mangler &Mang, bool MayAlwaysUsePrivate) const { if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) { // Simple case: If GV is not private, it is not important to find out if // private labels are legal in this case or not. Mang.getNameWithPrefix(Name, GV, false); return; } const TargetLoweringObjectFile *TLOF = getObjFileLowering(); TLOF->getNameWithPrefix(Name, GV, *this); } MCSymbol *TargetMachine::getSymbol(const GlobalValue *GV) const { const TargetLoweringObjectFile *TLOF = getObjFileLowering(); // XCOFF symbols could have special naming convention. if (MCSymbol *TargetSymbol = TLOF->getTargetSymbol(GV, *this)) return TargetSymbol; SmallString<128> NameStr; getNameWithPrefix(NameStr, GV, TLOF->getMangler()); return TLOF->getContext().getOrCreateSymbol(NameStr); } TargetIRAnalysis TargetMachine::getTargetIRAnalysis() { // Since Analysis can't depend on Target, use a std::function to invert the // dependency. return TargetIRAnalysis( [this](const Function &F) { return this->getTargetTransformInfo(F); }); } std::pair<int, int> TargetMachine::parseBinutilsVersion(StringRef Version) { if (Version == "none") return {INT_MAX, INT_MAX}; // Make binutilsIsAtLeast() return true. std::pair<int, int> Ret; if (!Version.consumeInteger(10, Ret.first) && Version.consume_front(".")) Version.consumeInteger(10, Ret.second); return Ret; }