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