1 //===-- BPFTargetMachine.cpp - Define TargetMachine for BPF ---------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // Implements the info about BPF target spec. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "BPFTargetMachine.h" 14 #include "BPF.h" 15 #include "BPFTargetTransformInfo.h" 16 #include "MCTargetDesc/BPFMCAsmInfo.h" 17 #include "TargetInfo/BPFTargetInfo.h" 18 #include "llvm/CodeGen/GlobalISel/IRTranslator.h" 19 #include "llvm/CodeGen/GlobalISel/InstructionSelect.h" 20 #include "llvm/CodeGen/GlobalISel/Legalizer.h" 21 #include "llvm/CodeGen/GlobalISel/RegBankSelect.h" 22 #include "llvm/CodeGen/Passes.h" 23 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h" 24 #include "llvm/CodeGen/TargetPassConfig.h" 25 #include "llvm/IR/PassManager.h" 26 #include "llvm/InitializePasses.h" 27 #include "llvm/MC/TargetRegistry.h" 28 #include "llvm/Passes/PassBuilder.h" 29 #include "llvm/Support/FormattedStream.h" 30 #include "llvm/Target/TargetOptions.h" 31 #include "llvm/Transforms/Scalar.h" 32 #include "llvm/Transforms/Scalar/SimplifyCFG.h" 33 #include "llvm/Transforms/Utils/SimplifyCFGOptions.h" 34 #include <optional> 35 using namespace llvm; 36 37 static cl:: 38 opt<bool> DisableMIPeephole("disable-bpf-peephole", cl::Hidden, 39 cl::desc("Disable machine peepholes for BPF")); 40 41 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeBPFTarget() { 42 // Register the target. 43 RegisterTargetMachine<BPFTargetMachine> X(getTheBPFleTarget()); 44 RegisterTargetMachine<BPFTargetMachine> Y(getTheBPFbeTarget()); 45 RegisterTargetMachine<BPFTargetMachine> Z(getTheBPFTarget()); 46 47 PassRegistry &PR = *PassRegistry::getPassRegistry(); 48 initializeGlobalISel(PR); 49 initializeBPFCheckAndAdjustIRPass(PR); 50 initializeBPFMIPeepholePass(PR); 51 initializeBPFDAGToDAGISelPass(PR); 52 } 53 54 // DataLayout: little or big endian 55 static std::string computeDataLayout(const Triple &TT) { 56 if (TT.getArch() == Triple::bpfeb) 57 return "E-m:e-p:64:64-i64:64-i128:128-n32:64-S128"; 58 else 59 return "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"; 60 } 61 62 static Reloc::Model getEffectiveRelocModel(std::optional<Reloc::Model> RM) { 63 return RM.value_or(Reloc::PIC_); 64 } 65 66 BPFTargetMachine::BPFTargetMachine(const Target &T, const Triple &TT, 67 StringRef CPU, StringRef FS, 68 const TargetOptions &Options, 69 std::optional<Reloc::Model> RM, 70 std::optional<CodeModel::Model> CM, 71 CodeGenOptLevel OL, bool JIT) 72 : LLVMTargetMachine(T, computeDataLayout(TT), TT, CPU, FS, Options, 73 getEffectiveRelocModel(RM), 74 getEffectiveCodeModel(CM, CodeModel::Small), OL), 75 TLOF(std::make_unique<TargetLoweringObjectFileELF>()), 76 Subtarget(TT, std::string(CPU), std::string(FS), *this) { 77 initAsmInfo(); 78 79 BPFMCAsmInfo *MAI = 80 static_cast<BPFMCAsmInfo *>(const_cast<MCAsmInfo *>(AsmInfo.get())); 81 MAI->setDwarfUsesRelocationsAcrossSections(!Subtarget.getUseDwarfRIS()); 82 } 83 84 namespace { 85 // BPF Code Generator Pass Configuration Options. 86 class BPFPassConfig : public TargetPassConfig { 87 public: 88 BPFPassConfig(BPFTargetMachine &TM, PassManagerBase &PM) 89 : TargetPassConfig(TM, PM) {} 90 91 BPFTargetMachine &getBPFTargetMachine() const { 92 return getTM<BPFTargetMachine>(); 93 } 94 95 void addIRPasses() override; 96 bool addInstSelector() override; 97 void addMachineSSAOptimization() override; 98 void addPreEmitPass() override; 99 100 bool addIRTranslator() override; 101 bool addLegalizeMachineIR() override; 102 bool addRegBankSelect() override; 103 bool addGlobalInstructionSelect() override; 104 }; 105 } 106 107 TargetPassConfig *BPFTargetMachine::createPassConfig(PassManagerBase &PM) { 108 return new BPFPassConfig(*this, PM); 109 } 110 111 void BPFTargetMachine::registerPassBuilderCallbacks( 112 PassBuilder &PB, bool PopulateClassToPassNames) { 113 PB.registerPipelineParsingCallback( 114 [](StringRef PassName, FunctionPassManager &FPM, 115 ArrayRef<PassBuilder::PipelineElement>) { 116 if (PassName == "bpf-ir-peephole") { 117 FPM.addPass(BPFIRPeepholePass()); 118 return true; 119 } 120 if (PassName == "bpf-preserve-static-offset") { 121 FPM.addPass(BPFPreserveStaticOffsetPass(false)); 122 return true; 123 } 124 return false; 125 }); 126 PB.registerPipelineStartEPCallback( 127 [=](ModulePassManager &MPM, OptimizationLevel) { 128 FunctionPassManager FPM; 129 FPM.addPass(BPFPreserveStaticOffsetPass(true)); 130 FPM.addPass(BPFAbstractMemberAccessPass(this)); 131 FPM.addPass(BPFPreserveDITypePass()); 132 FPM.addPass(BPFIRPeepholePass()); 133 MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM))); 134 }); 135 PB.registerPeepholeEPCallback([=](FunctionPassManager &FPM, 136 OptimizationLevel Level) { 137 FPM.addPass(SimplifyCFGPass(SimplifyCFGOptions().hoistCommonInsts(true))); 138 }); 139 PB.registerScalarOptimizerLateEPCallback( 140 [=](FunctionPassManager &FPM, OptimizationLevel Level) { 141 // Run this after loop unrolling but before 142 // SimplifyCFGPass(... .sinkCommonInsts(true)) 143 FPM.addPass(BPFPreserveStaticOffsetPass(false)); 144 }); 145 PB.registerPipelineEarlySimplificationEPCallback( 146 [=](ModulePassManager &MPM, OptimizationLevel) { 147 MPM.addPass(BPFAdjustOptPass()); 148 }); 149 } 150 151 void BPFPassConfig::addIRPasses() { 152 addPass(createAtomicExpandPass()); 153 addPass(createBPFCheckAndAdjustIR()); 154 155 TargetPassConfig::addIRPasses(); 156 } 157 158 TargetTransformInfo 159 BPFTargetMachine::getTargetTransformInfo(const Function &F) const { 160 return TargetTransformInfo(BPFTTIImpl(this, F)); 161 } 162 163 // Install an instruction selector pass using 164 // the ISelDag to gen BPF code. 165 bool BPFPassConfig::addInstSelector() { 166 addPass(createBPFISelDag(getBPFTargetMachine())); 167 168 return false; 169 } 170 171 void BPFPassConfig::addMachineSSAOptimization() { 172 addPass(createBPFMISimplifyPatchablePass()); 173 174 // The default implementation must be called first as we want eBPF 175 // Peephole ran at last. 176 TargetPassConfig::addMachineSSAOptimization(); 177 178 const BPFSubtarget *Subtarget = getBPFTargetMachine().getSubtargetImpl(); 179 if (!DisableMIPeephole) { 180 if (Subtarget->getHasAlu32()) 181 addPass(createBPFMIPeepholePass()); 182 } 183 } 184 185 void BPFPassConfig::addPreEmitPass() { 186 addPass(createBPFMIPreEmitCheckingPass()); 187 if (getOptLevel() != CodeGenOptLevel::None) 188 if (!DisableMIPeephole) 189 addPass(createBPFMIPreEmitPeepholePass()); 190 } 191 192 bool BPFPassConfig::addIRTranslator() { 193 addPass(new IRTranslator()); 194 return false; 195 } 196 197 bool BPFPassConfig::addLegalizeMachineIR() { 198 addPass(new Legalizer()); 199 return false; 200 } 201 202 bool BPFPassConfig::addRegBankSelect() { 203 addPass(new RegBankSelect()); 204 return false; 205 } 206 207 bool BPFPassConfig::addGlobalInstructionSelect() { 208 addPass(new InstructionSelect(getOptLevel())); 209 return false; 210 } 211