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/Passes.h" 19 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h" 20 #include "llvm/CodeGen/TargetPassConfig.h" 21 #include "llvm/IR/LegacyPassManager.h" 22 #include "llvm/IR/PassManager.h" 23 #include "llvm/MC/TargetRegistry.h" 24 #include "llvm/Passes/PassBuilder.h" 25 #include "llvm/Support/FormattedStream.h" 26 #include "llvm/Target/TargetOptions.h" 27 #include "llvm/Transforms/IPO/PassManagerBuilder.h" 28 #include "llvm/Transforms/Scalar.h" 29 #include "llvm/Transforms/Scalar/SimplifyCFG.h" 30 #include "llvm/Transforms/Utils/SimplifyCFGOptions.h" 31 using namespace llvm; 32 33 static cl:: 34 opt<bool> DisableMIPeephole("disable-bpf-peephole", cl::Hidden, 35 cl::desc("Disable machine peepholes for BPF")); 36 37 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeBPFTarget() { 38 // Register the target. 39 RegisterTargetMachine<BPFTargetMachine> X(getTheBPFleTarget()); 40 RegisterTargetMachine<BPFTargetMachine> Y(getTheBPFbeTarget()); 41 RegisterTargetMachine<BPFTargetMachine> Z(getTheBPFTarget()); 42 43 PassRegistry &PR = *PassRegistry::getPassRegistry(); 44 initializeBPFAbstractMemberAccessLegacyPassPass(PR); 45 initializeBPFPreserveDITypePass(PR); 46 initializeBPFIRPeepholePass(PR); 47 initializeBPFAdjustOptPass(PR); 48 initializeBPFCheckAndAdjustIRPass(PR); 49 initializeBPFMIPeepholePass(PR); 50 initializeBPFMIPeepholeTruncElimPass(PR); 51 } 52 53 // DataLayout: little or big endian 54 static std::string computeDataLayout(const Triple &TT) { 55 if (TT.getArch() == Triple::bpfeb) 56 return "E-m:e-p:64:64-i64:64-i128:128-n32:64-S128"; 57 else 58 return "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"; 59 } 60 61 static Reloc::Model getEffectiveRelocModel(Optional<Reloc::Model> RM) { 62 return RM.value_or(Reloc::PIC_); 63 } 64 65 BPFTargetMachine::BPFTargetMachine(const Target &T, const Triple &TT, 66 StringRef CPU, StringRef FS, 67 const TargetOptions &Options, 68 Optional<Reloc::Model> RM, 69 Optional<CodeModel::Model> CM, 70 CodeGenOpt::Level OL, bool JIT) 71 : LLVMTargetMachine(T, computeDataLayout(TT), TT, CPU, FS, Options, 72 getEffectiveRelocModel(RM), 73 getEffectiveCodeModel(CM, CodeModel::Small), OL), 74 TLOF(std::make_unique<TargetLoweringObjectFileELF>()), 75 Subtarget(TT, std::string(CPU), std::string(FS), *this) { 76 initAsmInfo(); 77 78 BPFMCAsmInfo *MAI = 79 static_cast<BPFMCAsmInfo *>(const_cast<MCAsmInfo *>(AsmInfo.get())); 80 MAI->setDwarfUsesRelocationsAcrossSections(!Subtarget.getUseDwarfRIS()); 81 } 82 83 namespace { 84 // BPF Code Generator Pass Configuration Options. 85 class BPFPassConfig : public TargetPassConfig { 86 public: 87 BPFPassConfig(BPFTargetMachine &TM, PassManagerBase &PM) 88 : TargetPassConfig(TM, PM) {} 89 90 BPFTargetMachine &getBPFTargetMachine() const { 91 return getTM<BPFTargetMachine>(); 92 } 93 94 void addIRPasses() override; 95 bool addInstSelector() override; 96 void addMachineSSAOptimization() override; 97 void addPreEmitPass() override; 98 }; 99 } 100 101 TargetPassConfig *BPFTargetMachine::createPassConfig(PassManagerBase &PM) { 102 return new BPFPassConfig(*this, PM); 103 } 104 105 void BPFTargetMachine::adjustPassManager(PassManagerBuilder &Builder) { 106 Builder.addExtension( 107 PassManagerBuilder::EP_EarlyAsPossible, 108 [&](const PassManagerBuilder &, legacy::PassManagerBase &PM) { 109 PM.add(createBPFAbstractMemberAccess(this)); 110 PM.add(createBPFPreserveDIType()); 111 PM.add(createBPFIRPeephole()); 112 }); 113 114 Builder.addExtension( 115 PassManagerBuilder::EP_Peephole, 116 [&](const PassManagerBuilder &, legacy::PassManagerBase &PM) { 117 PM.add(createCFGSimplificationPass( 118 SimplifyCFGOptions().hoistCommonInsts(true))); 119 }); 120 Builder.addExtension( 121 PassManagerBuilder::EP_ModuleOptimizerEarly, 122 [&](const PassManagerBuilder &, legacy::PassManagerBase &PM) { 123 PM.add(createBPFAdjustOpt()); 124 }); 125 } 126 127 void BPFTargetMachine::registerPassBuilderCallbacks(PassBuilder &PB) { 128 PB.registerPipelineStartEPCallback( 129 [=](ModulePassManager &MPM, OptimizationLevel) { 130 FunctionPassManager FPM; 131 FPM.addPass(BPFAbstractMemberAccessPass(this)); 132 FPM.addPass(BPFPreserveDITypePass()); 133 FPM.addPass(BPFIRPeepholePass()); 134 MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM))); 135 }); 136 PB.registerPeepholeEPCallback([=](FunctionPassManager &FPM, 137 OptimizationLevel Level) { 138 FPM.addPass(SimplifyCFGPass(SimplifyCFGOptions().hoistCommonInsts(true))); 139 }); 140 PB.registerPipelineEarlySimplificationEPCallback( 141 [=](ModulePassManager &MPM, OptimizationLevel) { 142 MPM.addPass(BPFAdjustOptPass()); 143 }); 144 } 145 146 void BPFPassConfig::addIRPasses() { 147 addPass(createBPFCheckAndAdjustIR()); 148 TargetPassConfig::addIRPasses(); 149 } 150 151 TargetTransformInfo 152 BPFTargetMachine::getTargetTransformInfo(const Function &F) const { 153 return TargetTransformInfo(BPFTTIImpl(this, F)); 154 } 155 156 // Install an instruction selector pass using 157 // the ISelDag to gen BPF code. 158 bool BPFPassConfig::addInstSelector() { 159 addPass(createBPFISelDag(getBPFTargetMachine())); 160 161 return false; 162 } 163 164 void BPFPassConfig::addMachineSSAOptimization() { 165 addPass(createBPFMISimplifyPatchablePass()); 166 167 // The default implementation must be called first as we want eBPF 168 // Peephole ran at last. 169 TargetPassConfig::addMachineSSAOptimization(); 170 171 const BPFSubtarget *Subtarget = getBPFTargetMachine().getSubtargetImpl(); 172 if (!DisableMIPeephole) { 173 if (Subtarget->getHasAlu32()) 174 addPass(createBPFMIPeepholePass()); 175 addPass(createBPFMIPeepholeTruncElimPass()); 176 } 177 } 178 179 void BPFPassConfig::addPreEmitPass() { 180 addPass(createBPFMIPreEmitCheckingPass()); 181 if (getOptLevel() != CodeGenOpt::None) 182 if (!DisableMIPeephole) 183 addPass(createBPFMIPreEmitPeepholePass()); 184 } 185