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/Support/FormattedStream.h" 22 #include "llvm/Support/TargetRegistry.h" 23 #include "llvm/Target/TargetOptions.h" 24 using namespace llvm; 25 26 static cl:: 27 opt<bool> DisableMIPeephole("disable-bpf-peephole", cl::Hidden, 28 cl::desc("Disable machine peepholes for BPF")); 29 30 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeBPFTarget() { 31 // Register the target. 32 RegisterTargetMachine<BPFTargetMachine> X(getTheBPFleTarget()); 33 RegisterTargetMachine<BPFTargetMachine> Y(getTheBPFbeTarget()); 34 RegisterTargetMachine<BPFTargetMachine> Z(getTheBPFTarget()); 35 36 PassRegistry &PR = *PassRegistry::getPassRegistry(); 37 initializeBPFAbstractMemberAccessPass(PR); 38 initializeBPFMIPeepholePass(PR); 39 initializeBPFMIPeepholeTruncElimPass(PR); 40 } 41 42 // DataLayout: little or big endian 43 static std::string computeDataLayout(const Triple &TT) { 44 if (TT.getArch() == Triple::bpfeb) 45 return "E-m:e-p:64:64-i64:64-n32:64-S128"; 46 else 47 return "e-m:e-p:64:64-i64:64-n32:64-S128"; 48 } 49 50 static Reloc::Model getEffectiveRelocModel(Optional<Reloc::Model> RM) { 51 if (!RM.hasValue()) 52 return Reloc::PIC_; 53 return *RM; 54 } 55 56 BPFTargetMachine::BPFTargetMachine(const Target &T, const Triple &TT, 57 StringRef CPU, StringRef FS, 58 const TargetOptions &Options, 59 Optional<Reloc::Model> RM, 60 Optional<CodeModel::Model> CM, 61 CodeGenOpt::Level OL, bool JIT) 62 : LLVMTargetMachine(T, computeDataLayout(TT), TT, CPU, FS, Options, 63 getEffectiveRelocModel(RM), 64 getEffectiveCodeModel(CM, CodeModel::Small), OL), 65 TLOF(std::make_unique<TargetLoweringObjectFileELF>()), 66 Subtarget(TT, CPU, FS, *this) { 67 initAsmInfo(); 68 69 BPFMCAsmInfo *MAI = 70 static_cast<BPFMCAsmInfo *>(const_cast<MCAsmInfo *>(AsmInfo.get())); 71 MAI->setDwarfUsesRelocationsAcrossSections(!Subtarget.getUseDwarfRIS()); 72 } 73 74 namespace { 75 // BPF Code Generator Pass Configuration Options. 76 class BPFPassConfig : public TargetPassConfig { 77 public: 78 BPFPassConfig(BPFTargetMachine &TM, PassManagerBase &PM) 79 : TargetPassConfig(TM, PM) {} 80 81 BPFTargetMachine &getBPFTargetMachine() const { 82 return getTM<BPFTargetMachine>(); 83 } 84 85 void addIRPasses() override; 86 bool addInstSelector() override; 87 void addMachineSSAOptimization() override; 88 void addPreEmitPass() override; 89 }; 90 } 91 92 TargetPassConfig *BPFTargetMachine::createPassConfig(PassManagerBase &PM) { 93 return new BPFPassConfig(*this, PM); 94 } 95 96 void BPFPassConfig::addIRPasses() { 97 98 addPass(createBPFAbstractMemberAccess(&getBPFTargetMachine())); 99 100 TargetPassConfig::addIRPasses(); 101 } 102 103 // Install an instruction selector pass using 104 // the ISelDag to gen BPF code. 105 bool BPFPassConfig::addInstSelector() { 106 addPass(createBPFISelDag(getBPFTargetMachine())); 107 108 return false; 109 } 110 111 void BPFPassConfig::addMachineSSAOptimization() { 112 addPass(createBPFMISimplifyPatchablePass()); 113 114 // The default implementation must be called first as we want eBPF 115 // Peephole ran at last. 116 TargetPassConfig::addMachineSSAOptimization(); 117 118 const BPFSubtarget *Subtarget = getBPFTargetMachine().getSubtargetImpl(); 119 if (!DisableMIPeephole) { 120 if (Subtarget->getHasAlu32()) 121 addPass(createBPFMIPeepholePass()); 122 addPass(createBPFMIPeepholeTruncElimPass()); 123 } 124 } 125 126 void BPFPassConfig::addPreEmitPass() { 127 addPass(createBPFMIPreEmitCheckingPass()); 128 if (getOptLevel() != CodeGenOpt::None) 129 if (!DisableMIPeephole) 130 addPass(createBPFMIPreEmitPeepholePass()); 131 } 132