//===-- X86TargetMachine.cpp - Define TargetMachine for the X86 -----------===// // // 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 defines the X86 specific subclass of TargetMachine. // //===----------------------------------------------------------------------===// #include "X86TargetMachine.h" #include "MCTargetDesc/X86MCTargetDesc.h" #include "TargetInfo/X86TargetInfo.h" #include "X86.h" #include "X86CallLowering.h" #include "X86LegalizerInfo.h" #include "X86MachineFunctionInfo.h" #include "X86MacroFusion.h" #include "X86Subtarget.h" #include "X86TargetObjectFile.h" #include "X86TargetTransformInfo.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/StringRef.h" #include "llvm/Analysis/TargetTransformInfo.h" #include "llvm/CodeGen/ExecutionDomainFix.h" #include "llvm/CodeGen/GlobalISel/CSEInfo.h" #include "llvm/CodeGen/GlobalISel/CallLowering.h" #include "llvm/CodeGen/GlobalISel/IRTranslator.h" #include "llvm/CodeGen/GlobalISel/InstructionSelect.h" #include "llvm/CodeGen/GlobalISel/InstructionSelector.h" #include "llvm/CodeGen/GlobalISel/Legalizer.h" #include "llvm/CodeGen/GlobalISel/RegBankSelect.h" #include "llvm/CodeGen/MachineScheduler.h" #include "llvm/CodeGen/Passes.h" #include "llvm/CodeGen/RegAllocRegistry.h" #include "llvm/CodeGen/TargetPassConfig.h" #include "llvm/IR/Attributes.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/Function.h" #include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/TargetRegistry.h" #include "llvm/Pass.h" #include "llvm/Support/CodeGen.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Target/TargetLoweringObjectFile.h" #include "llvm/Target/TargetOptions.h" #include "llvm/TargetParser/Triple.h" #include "llvm/Transforms/CFGuard.h" #include #include #include using namespace llvm; static cl::opt EnableMachineCombinerPass("x86-machine-combiner", cl::desc("Enable the machine combiner pass"), cl::init(true), cl::Hidden); static cl::opt EnableTileRAPass("x86-tile-ra", cl::desc("Enable the tile register allocation pass"), cl::init(true), cl::Hidden); extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeX86Target() { // Register the target. RegisterTargetMachine X(getTheX86_32Target()); RegisterTargetMachine Y(getTheX86_64Target()); PassRegistry &PR = *PassRegistry::getPassRegistry(); initializeX86LowerAMXIntrinsicsLegacyPassPass(PR); initializeX86LowerAMXTypeLegacyPassPass(PR); initializeX86PreAMXConfigPassPass(PR); initializeX86PreTileConfigPass(PR); initializeGlobalISel(PR); initializeWinEHStatePassPass(PR); initializeFixupBWInstPassPass(PR); initializeEvexToVexInstPassPass(PR); initializeFixupLEAPassPass(PR); initializeFPSPass(PR); initializeX86FixupSetCCPassPass(PR); initializeX86CallFrameOptimizationPass(PR); initializeX86CmovConverterPassPass(PR); initializeX86TileConfigPass(PR); initializeX86FastPreTileConfigPass(PR); initializeX86FastTileConfigPass(PR); initializeKCFIPass(PR); initializeX86LowerTileCopyPass(PR); initializeX86ExpandPseudoPass(PR); initializeX86ExecutionDomainFixPass(PR); initializeX86DomainReassignmentPass(PR); initializeX86AvoidSFBPassPass(PR); initializeX86AvoidTrailingCallPassPass(PR); initializeX86SpeculativeLoadHardeningPassPass(PR); initializeX86SpeculativeExecutionSideEffectSuppressionPass(PR); initializeX86FlagsCopyLoweringPassPass(PR); initializeX86LoadValueInjectionLoadHardeningPassPass(PR); initializeX86LoadValueInjectionRetHardeningPassPass(PR); initializeX86OptimizeLEAPassPass(PR); initializeX86PartialReductionPass(PR); initializePseudoProbeInserterPass(PR); initializeX86ReturnThunksPass(PR); initializeX86DAGToDAGISelPass(PR); initializeX86ArgumentStackSlotPassPass(PR); } static std::unique_ptr createTLOF(const Triple &TT) { if (TT.isOSBinFormatMachO()) { if (TT.getArch() == Triple::x86_64) return std::make_unique(); return std::make_unique(); } if (TT.isOSBinFormatCOFF()) return std::make_unique(); return std::make_unique(); } static std::string computeDataLayout(const Triple &TT) { // X86 is little endian std::string Ret = "e"; Ret += DataLayout::getManglingComponent(TT); // X86 and x32 have 32 bit pointers. if (!TT.isArch64Bit() || TT.isX32() || TT.isOSNaCl()) Ret += "-p:32:32"; // Address spaces for 32 bit signed, 32 bit unsigned, and 64 bit pointers. Ret += "-p270:32:32-p271:32:32-p272:64:64"; // Some ABIs align 64 bit integers and doubles to 64 bits, others to 32. if (TT.isArch64Bit() || TT.isOSWindows() || TT.isOSNaCl()) Ret += "-i64:64"; else if (TT.isOSIAMCU()) Ret += "-i64:32-f64:32"; else Ret += "-f64:32:64"; // Some ABIs align long double to 128 bits, others to 32. if (TT.isOSNaCl() || TT.isOSIAMCU()) ; // No f80 else if (TT.isArch64Bit() || TT.isOSDarwin() || TT.isWindowsMSVCEnvironment()) Ret += "-f80:128"; else Ret += "-f80:32"; if (TT.isOSIAMCU()) Ret += "-f128:32"; // The registers can hold 8, 16, 32 or, in x86-64, 64 bits. if (TT.isArch64Bit()) Ret += "-n8:16:32:64"; else Ret += "-n8:16:32"; // The stack is aligned to 32 bits on some ABIs and 128 bits on others. if ((!TT.isArch64Bit() && TT.isOSWindows()) || TT.isOSIAMCU()) Ret += "-a:0:32-S32"; else Ret += "-S128"; return Ret; } static Reloc::Model getEffectiveRelocModel(const Triple &TT, bool JIT, std::optional RM) { bool is64Bit = TT.getArch() == Triple::x86_64; if (!RM) { // JIT codegen should use static relocations by default, since it's // typically executed in process and not relocatable. if (JIT) return Reloc::Static; // Darwin defaults to PIC in 64 bit mode and dynamic-no-pic in 32 bit mode. // Win64 requires rip-rel addressing, thus we force it to PIC. Otherwise we // use static relocation model by default. if (TT.isOSDarwin()) { if (is64Bit) return Reloc::PIC_; return Reloc::DynamicNoPIC; } if (TT.isOSWindows() && is64Bit) return Reloc::PIC_; return Reloc::Static; } // ELF and X86-64 don't have a distinct DynamicNoPIC model. DynamicNoPIC // is defined as a model for code which may be used in static or dynamic // executables but not necessarily a shared library. On X86-32 we just // compile in -static mode, in x86-64 we use PIC. if (*RM == Reloc::DynamicNoPIC) { if (is64Bit) return Reloc::PIC_; if (!TT.isOSDarwin()) return Reloc::Static; } // If we are on Darwin, disallow static relocation model in X86-64 mode, since // the Mach-O file format doesn't support it. if (*RM == Reloc::Static && TT.isOSDarwin() && is64Bit) return Reloc::PIC_; return *RM; } static CodeModel::Model getEffectiveX86CodeModel(std::optional CM, bool JIT, bool Is64Bit) { if (CM) { if (*CM == CodeModel::Tiny) report_fatal_error("Target does not support the tiny CodeModel", false); return *CM; } if (JIT) return Is64Bit ? CodeModel::Large : CodeModel::Small; return CodeModel::Small; } /// Create an X86 target. /// X86TargetMachine::X86TargetMachine(const Target &T, const Triple &TT, StringRef CPU, StringRef FS, const TargetOptions &Options, std::optional RM, std::optional CM, CodeGenOpt::Level OL, bool JIT) : LLVMTargetMachine( T, computeDataLayout(TT), TT, CPU, FS, Options, getEffectiveRelocModel(TT, JIT, RM), getEffectiveX86CodeModel(CM, JIT, TT.getArch() == Triple::x86_64), OL), TLOF(createTLOF(getTargetTriple())), IsJIT(JIT) { // On PS4/PS5, the "return address" of a 'noreturn' call must still be within // the calling function, and TrapUnreachable is an easy way to get that. if (TT.isPS() || TT.isOSBinFormatMachO()) { this->Options.TrapUnreachable = true; this->Options.NoTrapAfterNoreturn = TT.isOSBinFormatMachO(); } setMachineOutliner(true); // x86 supports the debug entry values. setSupportsDebugEntryValues(true); initAsmInfo(); } X86TargetMachine::~X86TargetMachine() = default; const X86Subtarget * X86TargetMachine::getSubtargetImpl(const Function &F) const { Attribute CPUAttr = F.getFnAttribute("target-cpu"); Attribute TuneAttr = F.getFnAttribute("tune-cpu"); Attribute FSAttr = F.getFnAttribute("target-features"); StringRef CPU = CPUAttr.isValid() ? CPUAttr.getValueAsString() : (StringRef)TargetCPU; // "x86-64" is a default target setting for many front ends. In these cases, // they actually request for "generic" tuning unless the "tune-cpu" was // specified. StringRef TuneCPU = TuneAttr.isValid() ? TuneAttr.getValueAsString() : CPU == "x86-64" ? "generic" : (StringRef)CPU; StringRef FS = FSAttr.isValid() ? FSAttr.getValueAsString() : (StringRef)TargetFS; SmallString<512> Key; // The additions here are ordered so that the definitely short strings are // added first so we won't exceed the small size. We append the // much longer FS string at the end so that we only heap allocate at most // one time. // Extract prefer-vector-width attribute. unsigned PreferVectorWidthOverride = 0; Attribute PreferVecWidthAttr = F.getFnAttribute("prefer-vector-width"); if (PreferVecWidthAttr.isValid()) { StringRef Val = PreferVecWidthAttr.getValueAsString(); unsigned Width; if (!Val.getAsInteger(0, Width)) { Key += 'p'; Key += Val; PreferVectorWidthOverride = Width; } } // Extract min-legal-vector-width attribute. unsigned RequiredVectorWidth = UINT32_MAX; Attribute MinLegalVecWidthAttr = F.getFnAttribute("min-legal-vector-width"); if (MinLegalVecWidthAttr.isValid()) { StringRef Val = MinLegalVecWidthAttr.getValueAsString(); unsigned Width; if (!Val.getAsInteger(0, Width)) { Key += 'm'; Key += Val; RequiredVectorWidth = Width; } } // Add CPU to the Key. Key += CPU; // Add tune CPU to the Key. Key += TuneCPU; // Keep track of the start of the feature portion of the string. unsigned FSStart = Key.size(); // FIXME: This is related to the code below to reset the target options, // we need to know whether or not the soft float flag is set on the // function before we can generate a subtarget. We also need to use // it as a key for the subtarget since that can be the only difference // between two functions. bool SoftFloat = F.getFnAttribute("use-soft-float").getValueAsBool(); // If the soft float attribute is set on the function turn on the soft float // subtarget feature. if (SoftFloat) Key += FS.empty() ? "+soft-float" : "+soft-float,"; Key += FS; // We may have added +soft-float to the features so move the StringRef to // point to the full string in the Key. FS = Key.substr(FSStart); auto &I = SubtargetMap[Key]; if (!I) { // This needs to be done before we create a new subtarget since any // creation will depend on the TM and the code generation flags on the // function that reside in TargetOptions. resetTargetOptions(F); I = std::make_unique( TargetTriple, CPU, TuneCPU, FS, *this, MaybeAlign(F.getParent()->getOverrideStackAlignment()), PreferVectorWidthOverride, RequiredVectorWidth); } return I.get(); } bool X86TargetMachine::isNoopAddrSpaceCast(unsigned SrcAS, unsigned DestAS) const { assert(SrcAS != DestAS && "Expected different address spaces!"); if (getPointerSize(SrcAS) != getPointerSize(DestAS)) return false; return SrcAS < 256 && DestAS < 256; } //===----------------------------------------------------------------------===// // X86 TTI query. //===----------------------------------------------------------------------===// TargetTransformInfo X86TargetMachine::getTargetTransformInfo(const Function &F) const { return TargetTransformInfo(X86TTIImpl(this, F)); } //===----------------------------------------------------------------------===// // Pass Pipeline Configuration //===----------------------------------------------------------------------===// namespace { /// X86 Code Generator Pass Configuration Options. class X86PassConfig : public TargetPassConfig { public: X86PassConfig(X86TargetMachine &TM, PassManagerBase &PM) : TargetPassConfig(TM, PM) {} X86TargetMachine &getX86TargetMachine() const { return getTM(); } ScheduleDAGInstrs * createMachineScheduler(MachineSchedContext *C) const override { ScheduleDAGMILive *DAG = createGenericSchedLive(C); DAG->addMutation(createX86MacroFusionDAGMutation()); return DAG; } ScheduleDAGInstrs * createPostMachineScheduler(MachineSchedContext *C) const override { ScheduleDAGMI *DAG = createGenericSchedPostRA(C); DAG->addMutation(createX86MacroFusionDAGMutation()); return DAG; } void addIRPasses() override; bool addInstSelector() override; bool addIRTranslator() override; bool addLegalizeMachineIR() override; bool addRegBankSelect() override; bool addGlobalInstructionSelect() override; bool addILPOpts() override; bool addPreISel() override; void addMachineSSAOptimization() override; void addPreRegAlloc() override; bool addPostFastRegAllocRewrite() override; void addPostRegAlloc() override; void addPreEmitPass() override; void addPreEmitPass2() override; void addPreSched2() override; bool addRegAssignAndRewriteOptimized() override; std::unique_ptr getCSEConfig() const override; }; class X86ExecutionDomainFix : public ExecutionDomainFix { public: static char ID; X86ExecutionDomainFix() : ExecutionDomainFix(ID, X86::VR128XRegClass) {} StringRef getPassName() const override { return "X86 Execution Dependency Fix"; } }; char X86ExecutionDomainFix::ID; } // end anonymous namespace INITIALIZE_PASS_BEGIN(X86ExecutionDomainFix, "x86-execution-domain-fix", "X86 Execution Domain Fix", false, false) INITIALIZE_PASS_DEPENDENCY(ReachingDefAnalysis) INITIALIZE_PASS_END(X86ExecutionDomainFix, "x86-execution-domain-fix", "X86 Execution Domain Fix", false, false) TargetPassConfig *X86TargetMachine::createPassConfig(PassManagerBase &PM) { return new X86PassConfig(*this, PM); } MachineFunctionInfo *X86TargetMachine::createMachineFunctionInfo( BumpPtrAllocator &Allocator, const Function &F, const TargetSubtargetInfo *STI) const { return X86MachineFunctionInfo::create(Allocator, F, STI); } void X86PassConfig::addIRPasses() { addPass(createAtomicExpandPass()); // We add both pass anyway and when these two passes run, we skip the pass // based on the option level and option attribute. addPass(createX86LowerAMXIntrinsicsPass()); addPass(createX86LowerAMXTypePass()); TargetPassConfig::addIRPasses(); if (TM->getOptLevel() != CodeGenOpt::None) { addPass(createInterleavedAccessPass()); addPass(createX86PartialReductionPass()); } // Add passes that handle indirect branch removal and insertion of a retpoline // thunk. These will be a no-op unless a function subtarget has the retpoline // feature enabled. addPass(createIndirectBrExpandPass()); // Add Control Flow Guard checks. const Triple &TT = TM->getTargetTriple(); if (TT.isOSWindows()) { if (TT.getArch() == Triple::x86_64) { addPass(createCFGuardDispatchPass()); } else { addPass(createCFGuardCheckPass()); } } if (TM->Options.JMCInstrument) addPass(createJMCInstrumenterPass()); } bool X86PassConfig::addInstSelector() { // Install an instruction selector. addPass(createX86ISelDag(getX86TargetMachine(), getOptLevel())); // For ELF, cleanup any local-dynamic TLS accesses. if (TM->getTargetTriple().isOSBinFormatELF() && getOptLevel() != CodeGenOpt::None) addPass(createCleanupLocalDynamicTLSPass()); addPass(createX86GlobalBaseRegPass()); addPass(createX86ArgumentStackSlotPass()); return false; } bool X86PassConfig::addIRTranslator() { addPass(new IRTranslator(getOptLevel())); return false; } bool X86PassConfig::addLegalizeMachineIR() { addPass(new Legalizer()); return false; } bool X86PassConfig::addRegBankSelect() { addPass(new RegBankSelect()); return false; } bool X86PassConfig::addGlobalInstructionSelect() { addPass(new InstructionSelect(getOptLevel())); return false; } bool X86PassConfig::addILPOpts() { addPass(&EarlyIfConverterID); if (EnableMachineCombinerPass) addPass(&MachineCombinerID); addPass(createX86CmovConverterPass()); return true; } bool X86PassConfig::addPreISel() { // Only add this pass for 32-bit x86 Windows. const Triple &TT = TM->getTargetTriple(); if (TT.isOSWindows() && TT.getArch() == Triple::x86) addPass(createX86WinEHStatePass()); return true; } void X86PassConfig::addPreRegAlloc() { if (getOptLevel() != CodeGenOpt::None) { addPass(&LiveRangeShrinkID); addPass(createX86FixupSetCC()); addPass(createX86OptimizeLEAs()); addPass(createX86CallFrameOptimization()); addPass(createX86AvoidStoreForwardingBlocks()); } addPass(createX86SpeculativeLoadHardeningPass()); addPass(createX86FlagsCopyLoweringPass()); addPass(createX86DynAllocaExpander()); if (getOptLevel() != CodeGenOpt::None) addPass(createX86PreTileConfigPass()); else addPass(createX86FastPreTileConfigPass()); } void X86PassConfig::addMachineSSAOptimization() { addPass(createX86DomainReassignmentPass()); TargetPassConfig::addMachineSSAOptimization(); } void X86PassConfig::addPostRegAlloc() { addPass(createX86LowerTileCopyPass()); addPass(createX86FloatingPointStackifierPass()); // When -O0 is enabled, the Load Value Injection Hardening pass will fall back // to using the Speculative Execution Side Effect Suppression pass for // mitigation. This is to prevent slow downs due to // analyses needed by the LVIHardening pass when compiling at -O0. if (getOptLevel() != CodeGenOpt::None) addPass(createX86LoadValueInjectionLoadHardeningPass()); } void X86PassConfig::addPreSched2() { addPass(createX86ExpandPseudoPass()); addPass(createKCFIPass()); } void X86PassConfig::addPreEmitPass() { if (getOptLevel() != CodeGenOpt::None) { addPass(new X86ExecutionDomainFix()); addPass(createBreakFalseDeps()); } addPass(createX86IndirectBranchTrackingPass()); addPass(createX86IssueVZeroUpperPass()); if (getOptLevel() != CodeGenOpt::None) { addPass(createX86FixupBWInsts()); addPass(createX86PadShortFunctions()); addPass(createX86FixupLEAs()); addPass(createX86FixupInstTuning()); addPass(createX86FixupVectorConstants()); } addPass(createX86EvexToVexInsts()); addPass(createX86DiscriminateMemOpsPass()); addPass(createX86InsertPrefetchPass()); addPass(createX86InsertX87waitPass()); } void X86PassConfig::addPreEmitPass2() { const Triple &TT = TM->getTargetTriple(); const MCAsmInfo *MAI = TM->getMCAsmInfo(); // The X86 Speculative Execution Pass must run after all control // flow graph modifying passes. As a result it was listed to run right before // the X86 Retpoline Thunks pass. The reason it must run after control flow // graph modifications is that the model of LFENCE in LLVM has to be updated // (FIXME: https://bugs.llvm.org/show_bug.cgi?id=45167). Currently the // placement of this pass was hand checked to ensure that the subsequent // passes don't move the code around the LFENCEs in a way that will hurt the // correctness of this pass. This placement has been shown to work based on // hand inspection of the codegen output. addPass(createX86SpeculativeExecutionSideEffectSuppression()); addPass(createX86IndirectThunksPass()); addPass(createX86ReturnThunksPass()); // Insert extra int3 instructions after trailing call instructions to avoid // issues in the unwinder. if (TT.isOSWindows() && TT.getArch() == Triple::x86_64) addPass(createX86AvoidTrailingCallPass()); // Verify basic block incoming and outgoing cfa offset and register values and // correct CFA calculation rule where needed by inserting appropriate CFI // instructions. if (!TT.isOSDarwin() && (!TT.isOSWindows() || MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI)) addPass(createCFIInstrInserter()); if (TT.isOSWindows()) { // Identify valid longjmp targets for Windows Control Flow Guard. addPass(createCFGuardLongjmpPass()); // Identify valid eh continuation targets for Windows EHCont Guard. addPass(createEHContGuardCatchretPass()); } addPass(createX86LoadValueInjectionRetHardeningPass()); // Insert pseudo probe annotation for callsite profiling addPass(createPseudoProbeInserter()); // KCFI indirect call checks are lowered to a bundle, and on Darwin platforms, // also CALL_RVMARKER. addPass(createUnpackMachineBundles([&TT](const MachineFunction &MF) { // Only run bundle expansion if the module uses kcfi, or there are relevant // ObjC runtime functions present in the module. const Function &F = MF.getFunction(); const Module *M = F.getParent(); return M->getModuleFlag("kcfi") || (TT.isOSDarwin() && (M->getFunction("objc_retainAutoreleasedReturnValue") || M->getFunction("objc_unsafeClaimAutoreleasedReturnValue"))); })); } bool X86PassConfig::addPostFastRegAllocRewrite() { addPass(createX86FastTileConfigPass()); return true; } std::unique_ptr X86PassConfig::getCSEConfig() const { return getStandardCSEConfigForOpt(TM->getOptLevel()); } static bool onlyAllocateTileRegisters(const TargetRegisterInfo &TRI, const TargetRegisterClass &RC) { return static_cast(TRI).isTileRegisterClass(&RC); } bool X86PassConfig::addRegAssignAndRewriteOptimized() { // Don't support tile RA when RA is specified by command line "-regalloc". if (!isCustomizedRegAlloc() && EnableTileRAPass) { // Allocate tile register first. addPass(createGreedyRegisterAllocator(onlyAllocateTileRegisters)); addPass(createX86TileConfigPass()); } return TargetPassConfig::addRegAssignAndRewriteOptimized(); }