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https://github.com/capstone-engine/llvm-capstone.git
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0d333bf0e3
Currently clangDriver passes -femulated-tls and -fno-emulated-tls to cc1. cc1 forwards the option to LLVMCodeGen and ExplicitEmulatedTLS is used to decide the value. Simplify this by moving the Clang decision to clangDriver and moving the LLVM decision to InitTargetOptionsFromCodeGenFlags.
224 lines
8.2 KiB
C++
224 lines
8.2 KiB
C++
//===-- TargetMachine.cpp - General Target Information ---------------------==//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file describes the general parts of a Target machine.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Analysis/TargetTransformInfo.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/GlobalValue.h"
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#include "llvm/IR/GlobalVariable.h"
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#include "llvm/IR/Mangler.h"
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#include "llvm/MC/MCAsmInfo.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCInstrInfo.h"
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#include "llvm/MC/MCRegisterInfo.h"
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#include "llvm/MC/MCSubtargetInfo.h"
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#include "llvm/Target/TargetLoweringObjectFile.h"
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using namespace llvm;
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//---------------------------------------------------------------------------
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// TargetMachine Class
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//
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TargetMachine::TargetMachine(const Target &T, StringRef DataLayoutString,
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const Triple &TT, StringRef CPU, StringRef FS,
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const TargetOptions &Options)
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: TheTarget(T), DL(DataLayoutString), TargetTriple(TT),
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TargetCPU(std::string(CPU)), TargetFS(std::string(FS)), AsmInfo(nullptr),
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MRI(nullptr), MII(nullptr), STI(nullptr), RequireStructuredCFG(false),
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O0WantsFastISel(false), DefaultOptions(Options), Options(Options) {}
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TargetMachine::~TargetMachine() = default;
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bool TargetMachine::isPositionIndependent() const {
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return getRelocationModel() == Reloc::PIC_;
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}
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/// Reset the target options based on the function's attributes.
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/// setFunctionAttributes should have made the raw attribute value consistent
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/// with the command line flag if used.
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//
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// FIXME: This function needs to go away for a number of reasons:
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// a) global state on the TargetMachine is terrible in general,
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// b) these target options should be passed only on the function
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// and not on the TargetMachine (via TargetOptions) at all.
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void TargetMachine::resetTargetOptions(const Function &F) const {
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#define RESET_OPTION(X, Y) \
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do { \
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Options.X = F.getFnAttribute(Y).getValueAsBool(); \
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} while (0)
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RESET_OPTION(UnsafeFPMath, "unsafe-fp-math");
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RESET_OPTION(NoInfsFPMath, "no-infs-fp-math");
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RESET_OPTION(NoNaNsFPMath, "no-nans-fp-math");
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RESET_OPTION(NoSignedZerosFPMath, "no-signed-zeros-fp-math");
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RESET_OPTION(ApproxFuncFPMath, "approx-func-fp-math");
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}
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/// Returns the code generation relocation model. The choices are static, PIC,
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/// and dynamic-no-pic.
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Reloc::Model TargetMachine::getRelocationModel() const { return RM; }
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/// Get the IR-specified TLS model for Var.
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static TLSModel::Model getSelectedTLSModel(const GlobalValue *GV) {
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switch (GV->getThreadLocalMode()) {
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case GlobalVariable::NotThreadLocal:
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llvm_unreachable("getSelectedTLSModel for non-TLS variable");
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break;
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case GlobalVariable::GeneralDynamicTLSModel:
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return TLSModel::GeneralDynamic;
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case GlobalVariable::LocalDynamicTLSModel:
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return TLSModel::LocalDynamic;
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case GlobalVariable::InitialExecTLSModel:
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return TLSModel::InitialExec;
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case GlobalVariable::LocalExecTLSModel:
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return TLSModel::LocalExec;
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}
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llvm_unreachable("invalid TLS model");
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}
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bool TargetMachine::shouldAssumeDSOLocal(const Module &M,
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const GlobalValue *GV) const {
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const Triple &TT = getTargetTriple();
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Reloc::Model RM = getRelocationModel();
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// According to the llvm language reference, we should be able to
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// just return false in here if we have a GV, as we know it is
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// dso_preemptable. At this point in time, the various IR producers
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// have not been transitioned to always produce a dso_local when it
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// is possible to do so.
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//
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// As a result we still have some logic in here to improve the quality of the
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// generated code.
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if (!GV)
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return false;
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// If the IR producer requested that this GV be treated as dso local, obey.
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if (GV->isDSOLocal())
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return true;
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if (TT.isOSBinFormatCOFF()) {
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// DLLImport explicitly marks the GV as external.
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if (GV->hasDLLImportStorageClass())
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return false;
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// On MinGW, variables that haven't been declared with DLLImport may still
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// end up automatically imported by the linker. To make this feasible,
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// don't assume the variables to be DSO local unless we actually know
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// that for sure. This only has to be done for variables; for functions
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// the linker can insert thunks for calling functions from another DLL.
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if (TT.isWindowsGNUEnvironment() && GV->isDeclarationForLinker() &&
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isa<GlobalVariable>(GV))
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return false;
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// Don't mark 'extern_weak' symbols as DSO local. If these symbols remain
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// unresolved in the link, they can be resolved to zero, which is outside
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// the current DSO.
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if (GV->hasExternalWeakLinkage())
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return false;
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// Every other GV is local on COFF.
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return true;
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}
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if (TT.isOSBinFormatGOFF())
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return true;
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if (TT.isOSBinFormatMachO()) {
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if (RM == Reloc::Static)
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return true;
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return GV->isStrongDefinitionForLinker();
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}
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assert(TT.isOSBinFormatELF() || TT.isOSBinFormatWasm() ||
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TT.isOSBinFormatXCOFF());
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return false;
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}
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bool TargetMachine::useEmulatedTLS() const { return Options.EmulatedTLS; }
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TLSModel::Model TargetMachine::getTLSModel(const GlobalValue *GV) const {
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bool IsPIE = GV->getParent()->getPIELevel() != PIELevel::Default;
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Reloc::Model RM = getRelocationModel();
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bool IsSharedLibrary = RM == Reloc::PIC_ && !IsPIE;
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bool IsLocal = shouldAssumeDSOLocal(*GV->getParent(), GV);
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TLSModel::Model Model;
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if (IsSharedLibrary) {
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if (IsLocal)
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Model = TLSModel::LocalDynamic;
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else
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Model = TLSModel::GeneralDynamic;
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} else {
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if (IsLocal)
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Model = TLSModel::LocalExec;
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else
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Model = TLSModel::InitialExec;
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}
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// If the user specified a more specific model, use that.
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TLSModel::Model SelectedModel = getSelectedTLSModel(GV);
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if (SelectedModel > Model)
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return SelectedModel;
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return Model;
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}
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/// Returns the optimization level: None, Less, Default, or Aggressive.
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CodeGenOpt::Level TargetMachine::getOptLevel() const { return OptLevel; }
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void TargetMachine::setOptLevel(CodeGenOpt::Level Level) { OptLevel = Level; }
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TargetTransformInfo
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TargetMachine::getTargetTransformInfo(const Function &F) const {
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return TargetTransformInfo(F.getParent()->getDataLayout());
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}
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void TargetMachine::getNameWithPrefix(SmallVectorImpl<char> &Name,
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const GlobalValue *GV, Mangler &Mang,
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bool MayAlwaysUsePrivate) const {
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if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) {
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// Simple case: If GV is not private, it is not important to find out if
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// private labels are legal in this case or not.
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Mang.getNameWithPrefix(Name, GV, false);
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return;
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}
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const TargetLoweringObjectFile *TLOF = getObjFileLowering();
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TLOF->getNameWithPrefix(Name, GV, *this);
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}
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MCSymbol *TargetMachine::getSymbol(const GlobalValue *GV) const {
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const TargetLoweringObjectFile *TLOF = getObjFileLowering();
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// XCOFF symbols could have special naming convention.
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if (MCSymbol *TargetSymbol = TLOF->getTargetSymbol(GV, *this))
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return TargetSymbol;
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SmallString<128> NameStr;
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getNameWithPrefix(NameStr, GV, TLOF->getMangler());
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return TLOF->getContext().getOrCreateSymbol(NameStr);
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}
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TargetIRAnalysis TargetMachine::getTargetIRAnalysis() const {
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// Since Analysis can't depend on Target, use a std::function to invert the
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// dependency.
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return TargetIRAnalysis(
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[this](const Function &F) { return this->getTargetTransformInfo(F); });
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}
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std::pair<int, int> TargetMachine::parseBinutilsVersion(StringRef Version) {
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if (Version == "none")
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return {INT_MAX, INT_MAX}; // Make binutilsIsAtLeast() return true.
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std::pair<int, int> Ret;
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if (!Version.consumeInteger(10, Ret.first) && Version.consume_front("."))
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Version.consumeInteger(10, Ret.second);
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return Ret;
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}
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