//===-- PPCTargetMachine.cpp - Define TargetMachine for PowerPC -----------===// // // 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 // //===----------------------------------------------------------------------===// // // Top-level implementation for the PowerPC target. // //===----------------------------------------------------------------------===// #include "PPCTargetMachine.h" #include "MCTargetDesc/PPCMCTargetDesc.h" #include "PPC.h" #include "PPCMachineFunctionInfo.h" #include "PPCMachineScheduler.h" #include "PPCMacroFusion.h" #include "PPCSubtarget.h" #include "PPCTargetObjectFile.h" #include "PPCTargetTransformInfo.h" #include "TargetInfo/PowerPCTargetInfo.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/StringRef.h" #include "llvm/Analysis/TargetTransformInfo.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/Localizer.h" #include "llvm/CodeGen/GlobalISel/RegBankSelect.h" #include "llvm/CodeGen/MachineScheduler.h" #include "llvm/CodeGen/Passes.h" #include "llvm/CodeGen/TargetPassConfig.h" #include "llvm/IR/Attributes.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/Function.h" #include "llvm/InitializePasses.h" #include "llvm/MC/TargetRegistry.h" #include "llvm/Pass.h" #include "llvm/Support/CodeGen.h" #include "llvm/Support/CommandLine.h" #include "llvm/Target/TargetLoweringObjectFile.h" #include "llvm/Target/TargetOptions.h" #include "llvm/TargetParser/Triple.h" #include "llvm/Transforms/Scalar.h" #include #include #include #include using namespace llvm; static cl::opt EnableBranchCoalescing("enable-ppc-branch-coalesce", cl::Hidden, cl::desc("enable coalescing of duplicate branches for PPC")); static cl:: opt DisableCTRLoops("disable-ppc-ctrloops", cl::Hidden, cl::desc("Disable CTR loops for PPC")); static cl:: opt DisableInstrFormPrep("disable-ppc-instr-form-prep", cl::Hidden, cl::desc("Disable PPC loop instr form prep")); static cl::opt VSXFMAMutateEarly("schedule-ppc-vsx-fma-mutation-early", cl::Hidden, cl::desc("Schedule VSX FMA instruction mutation early")); static cl:: opt DisableVSXSwapRemoval("disable-ppc-vsx-swap-removal", cl::Hidden, cl::desc("Disable VSX Swap Removal for PPC")); static cl:: opt DisableMIPeephole("disable-ppc-peephole", cl::Hidden, cl::desc("Disable machine peepholes for PPC")); static cl::opt EnableGEPOpt("ppc-gep-opt", cl::Hidden, cl::desc("Enable optimizations on complex GEPs"), cl::init(true)); static cl::opt EnablePrefetch("enable-ppc-prefetching", cl::desc("enable software prefetching on PPC"), cl::init(false), cl::Hidden); static cl::opt EnableExtraTOCRegDeps("enable-ppc-extra-toc-reg-deps", cl::desc("Add extra TOC register dependencies"), cl::init(true), cl::Hidden); static cl::opt EnableMachineCombinerPass("ppc-machine-combiner", cl::desc("Enable the machine combiner pass"), cl::init(true), cl::Hidden); static cl::opt ReduceCRLogical("ppc-reduce-cr-logicals", cl::desc("Expand eligible cr-logical binary ops to branches"), cl::init(true), cl::Hidden); static cl::opt MergeStringPool( "ppc-merge-string-pool", cl::desc("Merge all of the strings in a module into one pool"), cl::init(true), cl::Hidden); static cl::opt EnablePPCGenScalarMASSEntries( "enable-ppc-gen-scalar-mass", cl::init(false), cl::desc("Enable lowering math functions to their corresponding MASS " "(scalar) entries"), cl::Hidden); extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializePowerPCTarget() { // Register the targets RegisterTargetMachine A(getThePPC32Target()); RegisterTargetMachine B(getThePPC32LETarget()); RegisterTargetMachine C(getThePPC64Target()); RegisterTargetMachine D(getThePPC64LETarget()); PassRegistry &PR = *PassRegistry::getPassRegistry(); #ifndef NDEBUG initializePPCCTRLoopsVerifyPass(PR); #endif initializePPCLoopInstrFormPrepPass(PR); initializePPCTOCRegDepsPass(PR); initializePPCEarlyReturnPass(PR); initializePPCVSXCopyPass(PR); initializePPCVSXFMAMutatePass(PR); initializePPCVSXSwapRemovalPass(PR); initializePPCReduceCRLogicalsPass(PR); initializePPCBSelPass(PR); initializePPCBranchCoalescingPass(PR); initializePPCBoolRetToIntPass(PR); initializePPCExpandISELPass(PR); initializePPCPreEmitPeepholePass(PR); initializePPCTLSDynamicCallPass(PR); initializePPCMIPeepholePass(PR); initializePPCLowerMASSVEntriesPass(PR); initializePPCGenScalarMASSEntriesPass(PR); initializePPCExpandAtomicPseudoPass(PR); initializeGlobalISel(PR); initializePPCCTRLoopsPass(PR); initializePPCDAGToDAGISelPass(PR); initializePPCMergeStringPoolPass(PR); } static bool isLittleEndianTriple(const Triple &T) { return T.getArch() == Triple::ppc64le || T.getArch() == Triple::ppcle; } /// Return the datalayout string of a subtarget. static std::string getDataLayoutString(const Triple &T) { bool is64Bit = T.getArch() == Triple::ppc64 || T.getArch() == Triple::ppc64le; std::string Ret; // Most PPC* platforms are big endian, PPC(64)LE is little endian. if (isLittleEndianTriple(T)) Ret = "e"; else Ret = "E"; Ret += DataLayout::getManglingComponent(T); // PPC32 has 32 bit pointers. The PS3 (OS Lv2) is a PPC64 machine with 32 bit // pointers. if (!is64Bit || T.getOS() == Triple::Lv2) Ret += "-p:32:32"; // If the target ABI uses function descriptors, then the alignment of function // pointers depends on the alignment used to emit the descriptor. Otherwise, // function pointers are aligned to 32 bits because the instructions must be. if ((T.getArch() == Triple::ppc64 && !T.isPPC64ELFv2ABI())) { Ret += "-Fi64"; } else if (T.isOSAIX()) { Ret += is64Bit ? "-Fi64" : "-Fi32"; } else { Ret += "-Fn32"; } // Note, the alignment values for f64 and i64 on ppc64 in Darwin // documentation are wrong; these are correct (i.e. "what gcc does"). Ret += "-i64:64"; // PPC64 has 32 and 64 bit registers, PPC32 has only 32 bit ones. if (is64Bit) Ret += "-n32:64"; else Ret += "-n32"; // Specify the vector alignment explicitly. For v256i1 and v512i1, the // calculated alignment would be 256*alignment(i1) and 512*alignment(i1), // which is 256 and 512 bytes - way over aligned. if (is64Bit && (T.isOSAIX() || T.isOSLinux())) Ret += "-S128-v256:256:256-v512:512:512"; return Ret; } static std::string computeFSAdditions(StringRef FS, CodeGenOptLevel OL, const Triple &TT) { std::string FullFS = std::string(FS); // Make sure 64-bit features are available when CPUname is generic if (TT.getArch() == Triple::ppc64 || TT.getArch() == Triple::ppc64le) { if (!FullFS.empty()) FullFS = "+64bit," + FullFS; else FullFS = "+64bit"; } if (OL >= CodeGenOptLevel::Default) { if (!FullFS.empty()) FullFS = "+crbits," + FullFS; else FullFS = "+crbits"; } if (OL != CodeGenOptLevel::None) { if (!FullFS.empty()) FullFS = "+invariant-function-descriptors," + FullFS; else FullFS = "+invariant-function-descriptors"; } if (TT.isOSAIX()) { if (!FullFS.empty()) FullFS = "+aix," + FullFS; else FullFS = "+aix"; } return FullFS; } static std::unique_ptr createTLOF(const Triple &TT) { if (TT.isOSAIX()) return std::make_unique(); return std::make_unique(); } static PPCTargetMachine::PPCABI computeTargetABI(const Triple &TT, const TargetOptions &Options) { if (Options.MCOptions.getABIName().starts_with("elfv1")) return PPCTargetMachine::PPC_ABI_ELFv1; else if (Options.MCOptions.getABIName().starts_with("elfv2")) return PPCTargetMachine::PPC_ABI_ELFv2; assert(Options.MCOptions.getABIName().empty() && "Unknown target-abi option!"); switch (TT.getArch()) { case Triple::ppc64le: return PPCTargetMachine::PPC_ABI_ELFv2; case Triple::ppc64: if (TT.isPPC64ELFv2ABI()) return PPCTargetMachine::PPC_ABI_ELFv2; else return PPCTargetMachine::PPC_ABI_ELFv1; default: return PPCTargetMachine::PPC_ABI_UNKNOWN; } } static Reloc::Model getEffectiveRelocModel(const Triple &TT, std::optional RM) { if (TT.isOSAIX() && RM && *RM != Reloc::PIC_) report_fatal_error("invalid relocation model, AIX only supports PIC", false); if (RM) return *RM; // Big Endian PPC and AIX default to PIC. if (TT.getArch() == Triple::ppc64 || TT.isOSAIX()) return Reloc::PIC_; // Rest are static by default. return Reloc::Static; } static CodeModel::Model getEffectivePPCCodeModel(const Triple &TT, std::optional CM, bool JIT) { if (CM) { if (*CM == CodeModel::Tiny) report_fatal_error("Target does not support the tiny CodeModel", false); if (*CM == CodeModel::Kernel) report_fatal_error("Target does not support the kernel CodeModel", false); return *CM; } if (JIT) return CodeModel::Small; if (TT.isOSAIX()) return CodeModel::Small; assert(TT.isOSBinFormatELF() && "All remaining PPC OSes are ELF based."); if (TT.isArch32Bit()) return CodeModel::Small; assert(TT.isArch64Bit() && "Unsupported PPC architecture."); return CodeModel::Medium; } static ScheduleDAGInstrs *createPPCMachineScheduler(MachineSchedContext *C) { const PPCSubtarget &ST = C->MF->getSubtarget(); ScheduleDAGMILive *DAG = new ScheduleDAGMILive(C, ST.usePPCPreRASchedStrategy() ? std::make_unique(C) : std::make_unique(C)); // add DAG Mutations here. DAG->addMutation(createCopyConstrainDAGMutation(DAG->TII, DAG->TRI)); if (ST.hasStoreFusion()) DAG->addMutation(createStoreClusterDAGMutation(DAG->TII, DAG->TRI)); if (ST.hasFusion()) DAG->addMutation(createPowerPCMacroFusionDAGMutation()); return DAG; } static ScheduleDAGInstrs *createPPCPostMachineScheduler( MachineSchedContext *C) { const PPCSubtarget &ST = C->MF->getSubtarget(); ScheduleDAGMI *DAG = new ScheduleDAGMI(C, ST.usePPCPostRASchedStrategy() ? std::make_unique(C) : std::make_unique(C), true); // add DAG Mutations here. if (ST.hasStoreFusion()) DAG->addMutation(createStoreClusterDAGMutation(DAG->TII, DAG->TRI)); if (ST.hasFusion()) DAG->addMutation(createPowerPCMacroFusionDAGMutation()); return DAG; } // The FeatureString here is a little subtle. We are modifying the feature // string with what are (currently) non-function specific overrides as it goes // into the LLVMTargetMachine constructor and then using the stored value in the // Subtarget constructor below it. PPCTargetMachine::PPCTargetMachine(const Target &T, const Triple &TT, StringRef CPU, StringRef FS, const TargetOptions &Options, std::optional RM, std::optional CM, CodeGenOptLevel OL, bool JIT) : LLVMTargetMachine(T, getDataLayoutString(TT), TT, CPU, computeFSAdditions(FS, OL, TT), Options, getEffectiveRelocModel(TT, RM), getEffectivePPCCodeModel(TT, CM, JIT), OL), TLOF(createTLOF(getTargetTriple())), TargetABI(computeTargetABI(TT, Options)), Endianness(isLittleEndianTriple(TT) ? Endian::LITTLE : Endian::BIG) { initAsmInfo(); } PPCTargetMachine::~PPCTargetMachine() = default; const PPCSubtarget * PPCTargetMachine::getSubtargetImpl(const Function &F) const { Attribute CPUAttr = F.getFnAttribute("target-cpu"); Attribute TuneAttr = F.getFnAttribute("tune-cpu"); Attribute FSAttr = F.getFnAttribute("target-features"); std::string CPU = CPUAttr.isValid() ? CPUAttr.getValueAsString().str() : TargetCPU; std::string TuneCPU = TuneAttr.isValid() ? TuneAttr.getValueAsString().str() : CPU; std::string FS = FSAttr.isValid() ? FSAttr.getValueAsString().str() : TargetFS; // 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) FS += FS.empty() ? "-hard-float" : ",-hard-float"; auto &I = SubtargetMap[CPU + TuneCPU + FS]; 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, // FIXME: It would be good to have the subtarget additions here // not necessary. Anything that turns them on/off (overrides) ends // up being put at the end of the feature string, but the defaults // shouldn't require adding them. Fixing this means pulling Feature64Bit // out of most of the target cpus in the .td file and making it set only // as part of initialization via the TargetTriple. computeFSAdditions(FS, getOptLevel(), getTargetTriple()), *this); } return I.get(); } //===----------------------------------------------------------------------===// // Pass Pipeline Configuration //===----------------------------------------------------------------------===// namespace { /// PPC Code Generator Pass Configuration Options. class PPCPassConfig : public TargetPassConfig { public: PPCPassConfig(PPCTargetMachine &TM, PassManagerBase &PM) : TargetPassConfig(TM, PM) { // At any optimization level above -O0 we use the Machine Scheduler and not // the default Post RA List Scheduler. if (TM.getOptLevel() != CodeGenOptLevel::None) substitutePass(&PostRASchedulerID, &PostMachineSchedulerID); } PPCTargetMachine &getPPCTargetMachine() const { return getTM(); } void addIRPasses() override; bool addPreISel() override; bool addILPOpts() override; bool addInstSelector() override; void addMachineSSAOptimization() override; void addPreRegAlloc() override; void addPreSched2() override; void addPreEmitPass() override; void addPreEmitPass2() override; // GlobalISEL bool addIRTranslator() override; bool addLegalizeMachineIR() override; bool addRegBankSelect() override; bool addGlobalInstructionSelect() override; ScheduleDAGInstrs * createMachineScheduler(MachineSchedContext *C) const override { return createPPCMachineScheduler(C); } ScheduleDAGInstrs * createPostMachineScheduler(MachineSchedContext *C) const override { return createPPCPostMachineScheduler(C); } }; } // end anonymous namespace TargetPassConfig *PPCTargetMachine::createPassConfig(PassManagerBase &PM) { return new PPCPassConfig(*this, PM); } void PPCPassConfig::addIRPasses() { if (TM->getOptLevel() != CodeGenOptLevel::None) addPass(createPPCBoolRetToIntPass()); addPass(createAtomicExpandPass()); // Lower generic MASSV routines to PowerPC subtarget-specific entries. addPass(createPPCLowerMASSVEntriesPass()); // Generate PowerPC target-specific entries for scalar math functions // that are available in IBM MASS (scalar) library. if (TM->getOptLevel() == CodeGenOptLevel::Aggressive && EnablePPCGenScalarMASSEntries) { TM->Options.PPCGenScalarMASSEntries = EnablePPCGenScalarMASSEntries; addPass(createPPCGenScalarMASSEntriesPass()); } // If explicitly requested, add explicit data prefetch intrinsics. if (EnablePrefetch.getNumOccurrences() > 0) addPass(createLoopDataPrefetchPass()); if (TM->getOptLevel() >= CodeGenOptLevel::Default && EnableGEPOpt) { // Call SeparateConstOffsetFromGEP pass to extract constants within indices // and lower a GEP with multiple indices to either arithmetic operations or // multiple GEPs with single index. addPass(createSeparateConstOffsetFromGEPPass(true)); // Call EarlyCSE pass to find and remove subexpressions in the lowered // result. addPass(createEarlyCSEPass()); // Do loop invariant code motion in case part of the lowered result is // invariant. addPass(createLICMPass()); } TargetPassConfig::addIRPasses(); } bool PPCPassConfig::addPreISel() { if (MergeStringPool && getOptLevel() != CodeGenOptLevel::None) addPass(createPPCMergeStringPoolPass()); if (!DisableInstrFormPrep && getOptLevel() != CodeGenOptLevel::None) addPass(createPPCLoopInstrFormPrepPass(getPPCTargetMachine())); if (!DisableCTRLoops && getOptLevel() != CodeGenOptLevel::None) addPass(createHardwareLoopsLegacyPass()); return false; } bool PPCPassConfig::addILPOpts() { addPass(&EarlyIfConverterID); if (EnableMachineCombinerPass) addPass(&MachineCombinerID); return true; } bool PPCPassConfig::addInstSelector() { // Install an instruction selector. addPass(createPPCISelDag(getPPCTargetMachine(), getOptLevel())); #ifndef NDEBUG if (!DisableCTRLoops && getOptLevel() != CodeGenOptLevel::None) addPass(createPPCCTRLoopsVerify()); #endif addPass(createPPCVSXCopyPass()); return false; } void PPCPassConfig::addMachineSSAOptimization() { // Run CTR loops pass before any cfg modification pass to prevent the // canonical form of hardware loop from being destroied. if (!DisableCTRLoops && getOptLevel() != CodeGenOptLevel::None) addPass(createPPCCTRLoopsPass()); // PPCBranchCoalescingPass need to be done before machine sinking // since it merges empty blocks. if (EnableBranchCoalescing && getOptLevel() != CodeGenOptLevel::None) addPass(createPPCBranchCoalescingPass()); TargetPassConfig::addMachineSSAOptimization(); // For little endian, remove where possible the vector swap instructions // introduced at code generation to normalize vector element order. if (TM->getTargetTriple().getArch() == Triple::ppc64le && !DisableVSXSwapRemoval) addPass(createPPCVSXSwapRemovalPass()); // Reduce the number of cr-logical ops. if (ReduceCRLogical && getOptLevel() != CodeGenOptLevel::None) addPass(createPPCReduceCRLogicalsPass()); // Target-specific peephole cleanups performed after instruction // selection. if (!DisableMIPeephole) { addPass(createPPCMIPeepholePass()); addPass(&DeadMachineInstructionElimID); } } void PPCPassConfig::addPreRegAlloc() { if (getOptLevel() != CodeGenOptLevel::None) { initializePPCVSXFMAMutatePass(*PassRegistry::getPassRegistry()); insertPass(VSXFMAMutateEarly ? &RegisterCoalescerID : &MachineSchedulerID, &PPCVSXFMAMutateID); } // FIXME: We probably don't need to run these for -fPIE. if (getPPCTargetMachine().isPositionIndependent()) { // FIXME: LiveVariables should not be necessary here! // PPCTLSDynamicCallPass uses LiveIntervals which previously dependent on // LiveVariables. This (unnecessary) dependency has been removed now, // however a stage-2 clang build fails without LiveVariables computed here. addPass(&LiveVariablesID); addPass(createPPCTLSDynamicCallPass()); } if (EnableExtraTOCRegDeps) addPass(createPPCTOCRegDepsPass()); if (getOptLevel() != CodeGenOptLevel::None) addPass(&MachinePipelinerID); } void PPCPassConfig::addPreSched2() { if (getOptLevel() != CodeGenOptLevel::None) addPass(&IfConverterID); } void PPCPassConfig::addPreEmitPass() { addPass(createPPCPreEmitPeepholePass()); addPass(createPPCExpandISELPass()); if (getOptLevel() != CodeGenOptLevel::None) addPass(createPPCEarlyReturnPass()); } void PPCPassConfig::addPreEmitPass2() { // Schedule the expansion of AMOs at the last possible moment, avoiding the // possibility for other passes to break the requirements for forward // progress in the LL/SC block. addPass(createPPCExpandAtomicPseudoPass()); // Must run branch selection immediately preceding the asm printer. addPass(createPPCBranchSelectionPass()); } TargetTransformInfo PPCTargetMachine::getTargetTransformInfo(const Function &F) const { return TargetTransformInfo(PPCTTIImpl(this, F)); } bool PPCTargetMachine::isLittleEndian() const { assert(Endianness != Endian::NOT_DETECTED && "Unable to determine endianness"); return Endianness == Endian::LITTLE; } MachineFunctionInfo *PPCTargetMachine::createMachineFunctionInfo( BumpPtrAllocator &Allocator, const Function &F, const TargetSubtargetInfo *STI) const { return PPCFunctionInfo::create(Allocator, F, STI); } static MachineSchedRegistry PPCPreRASchedRegistry("ppc-prera", "Run PowerPC PreRA specific scheduler", createPPCMachineScheduler); static MachineSchedRegistry PPCPostRASchedRegistry("ppc-postra", "Run PowerPC PostRA specific scheduler", createPPCPostMachineScheduler); // Global ISEL bool PPCPassConfig::addIRTranslator() { addPass(new IRTranslator()); return false; } bool PPCPassConfig::addLegalizeMachineIR() { addPass(new Legalizer()); return false; } bool PPCPassConfig::addRegBankSelect() { addPass(new RegBankSelect()); return false; } bool PPCPassConfig::addGlobalInstructionSelect() { addPass(new InstructionSelect(getOptLevel())); return false; }