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 "MCTargetDesc/BPFMCAsmInfo.h" 16 #include "TargetInfo/BPFTargetInfo.h" 17 #include "llvm/CodeGen/Passes.h" 18 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h" 19 #include "llvm/CodeGen/TargetPassConfig.h" 20 #include "llvm/IR/LegacyPassManager.h" 21 #include "llvm/IR/PassManager.h" 22 #include "llvm/Passes/PassBuilder.h" 23 #include "llvm/Support/FormattedStream.h" 24 #include "llvm/Support/TargetRegistry.h" 25 #include "llvm/Target/TargetOptions.h" 26 #include "llvm/Transforms/IPO/PassManagerBuilder.h" 27 #include "llvm/Transforms/Scalar.h" 28 #include "llvm/Transforms/Scalar/SimplifyCFG.h" 29 #include "llvm/Transforms/Utils/SimplifyCFGOptions.h" 30 using namespace llvm; 31 32 static cl:: 33 opt<bool> DisableMIPeephole("disable-bpf-peephole", cl::Hidden, 34 cl::desc("Disable machine peepholes for BPF")); 35 36 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeBPFTarget() { 37 // Register the target. 38 RegisterTargetMachine<BPFTargetMachine> X(getTheBPFleTarget()); 39 RegisterTargetMachine<BPFTargetMachine> Y(getTheBPFbeTarget()); 40 RegisterTargetMachine<BPFTargetMachine> Z(getTheBPFTarget()); 41 42 PassRegistry &PR = *PassRegistry::getPassRegistry(); 43 initializeBPFAbstractMemberAccessLegacyPassPass(PR); 44 initializeBPFPreserveDITypePass(PR); 45 initializeBPFAdjustOptPass(PR); 46 initializeBPFCheckAndAdjustIRPass(PR); 47 initializeBPFMIPeepholePass(PR); 48 initializeBPFMIPeepholeTruncElimPass(PR); 49 } 50 51 // DataLayout: little or big endian 52 static std::string computeDataLayout(const Triple &TT) { 53 if (TT.getArch() == Triple::bpfeb) 54 return "E-m:e-p:64:64-i64:64-i128:128-n32:64-S128"; 55 else 56 return "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"; 57 } 58 59 static Reloc::Model getEffectiveRelocModel(Optional<Reloc::Model> RM) { 60 return RM.getValueOr(Reloc::PIC_); 61 } 62 63 BPFTargetMachine::BPFTargetMachine(const Target &T, const Triple &TT, 64 StringRef CPU, StringRef FS, 65 const TargetOptions &Options, 66 Optional<Reloc::Model> RM, 67 Optional<CodeModel::Model> CM, 68 CodeGenOpt::Level OL, bool JIT) 69 : LLVMTargetMachine(T, computeDataLayout(TT), TT, CPU, FS, Options, 70 getEffectiveRelocModel(RM), 71 getEffectiveCodeModel(CM, CodeModel::Small), OL), 72 TLOF(std::make_unique<TargetLoweringObjectFileELF>()), 73 Subtarget(TT, std::string(CPU), std::string(FS), *this) { 74 initAsmInfo(); 75 76 BPFMCAsmInfo *MAI = 77 static_cast<BPFMCAsmInfo *>(const_cast<MCAsmInfo *>(AsmInfo.get())); 78 MAI->setDwarfUsesRelocationsAcrossSections(!Subtarget.getUseDwarfRIS()); 79 } 80 81 namespace { 82 // BPF Code Generator Pass Configuration Options. 83 class BPFPassConfig : public TargetPassConfig { 84 public: 85 BPFPassConfig(BPFTargetMachine &TM, PassManagerBase &PM) 86 : TargetPassConfig(TM, PM) {} 87 88 BPFTargetMachine &getBPFTargetMachine() const { 89 return getTM<BPFTargetMachine>(); 90 } 91 92 void addIRPasses() override; 93 bool addInstSelector() override; 94 void addMachineSSAOptimization() override; 95 void addPreEmitPass() override; 96 }; 97 } 98 99 TargetPassConfig *BPFTargetMachine::createPassConfig(PassManagerBase &PM) { 100 return new BPFPassConfig(*this, PM); 101 } 102 103 void BPFTargetMachine::adjustPassManager(PassManagerBuilder &Builder) { 104 Builder.addExtension( 105 PassManagerBuilder::EP_EarlyAsPossible, 106 [&](const PassManagerBuilder &, legacy::PassManagerBase &PM) { 107 PM.add(createBPFAbstractMemberAccess(this)); 108 PM.add(createBPFPreserveDIType()); 109 }); 110 111 Builder.addExtension( 112 PassManagerBuilder::EP_Peephole, 113 [&](const PassManagerBuilder &, legacy::PassManagerBase &PM) { 114 PM.add(createCFGSimplificationPass( 115 SimplifyCFGOptions().hoistCommonInsts(true))); 116 }); 117 Builder.addExtension( 118 PassManagerBuilder::EP_ModuleOptimizerEarly, 119 [&](const PassManagerBuilder &, legacy::PassManagerBase &PM) { 120 PM.add(createBPFAdjustOpt()); 121 }); 122 } 123 124 void BPFTargetMachine::registerPassBuilderCallbacks(PassBuilder &PB, 125 bool DebugPassManager) { 126 PB.registerPipelineStartEPCallback( 127 [=](ModulePassManager &MPM, PassBuilder::OptimizationLevel) { 128 FunctionPassManager FPM(DebugPassManager); 129 FPM.addPass(BPFAbstractMemberAccessPass(this)); 130 FPM.addPass(BPFPreserveDITypePass()); 131 MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM))); 132 }); 133 PB.registerPeepholeEPCallback([=](FunctionPassManager &FPM, 134 PassBuilder::OptimizationLevel Level) { 135 FPM.addPass(SimplifyCFGPass(SimplifyCFGOptions().hoistCommonInsts(true))); 136 }); 137 PB.registerPipelineEarlySimplificationEPCallback( 138 [=](ModulePassManager &MPM, PassBuilder::OptimizationLevel) { 139 MPM.addPass(BPFAdjustOptPass()); 140 }); 141 } 142 143 void BPFPassConfig::addIRPasses() { 144 addPass(createBPFCheckAndAdjustIR()); 145 TargetPassConfig::addIRPasses(); 146 } 147 148 // Install an instruction selector pass using 149 // the ISelDag to gen BPF code. 150 bool BPFPassConfig::addInstSelector() { 151 addPass(createBPFISelDag(getBPFTargetMachine())); 152 153 return false; 154 } 155 156 void BPFPassConfig::addMachineSSAOptimization() { 157 addPass(createBPFMISimplifyPatchablePass()); 158 159 // The default implementation must be called first as we want eBPF 160 // Peephole ran at last. 161 TargetPassConfig::addMachineSSAOptimization(); 162 163 const BPFSubtarget *Subtarget = getBPFTargetMachine().getSubtargetImpl(); 164 if (!DisableMIPeephole) { 165 if (Subtarget->getHasAlu32()) 166 addPass(createBPFMIPeepholePass()); 167 addPass(createBPFMIPeepholeTruncElimPass()); 168 } 169 } 170 171 void BPFPassConfig::addPreEmitPass() { 172 addPass(createBPFMIPreEmitCheckingPass()); 173 if (getOptLevel() != CodeGenOpt::None) 174 if (!DisableMIPeephole) 175 addPass(createBPFMIPreEmitPeepholePass()); 176 } 177