158 lines · cpp
1//===-- BPFMCTargetDesc.cpp - BPF Target Descriptions ---------------------===//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-exception6//7//===----------------------------------------------------------------------===//8//9// This file provides BPF specific target descriptions.10//11//===----------------------------------------------------------------------===//12 13#include "MCTargetDesc/BPFMCTargetDesc.h"14#include "MCTargetDesc/BPFInstPrinter.h"15#include "MCTargetDesc/BPFMCAsmInfo.h"16#include "TargetInfo/BPFTargetInfo.h"17#include "llvm/MC/MCInstrAnalysis.h"18#include "llvm/MC/MCInstrInfo.h"19#include "llvm/MC/MCRegisterInfo.h"20#include "llvm/MC/MCSubtargetInfo.h"21#include "llvm/MC/TargetRegistry.h"22#include "llvm/Support/Compiler.h"23#include "llvm/TargetParser/Host.h"24 25#define GET_INSTRINFO_MC_DESC26#define ENABLE_INSTR_PREDICATE_VERIFIER27#include "BPFGenInstrInfo.inc"28 29#define GET_SUBTARGETINFO_MC_DESC30#include "BPFGenSubtargetInfo.inc"31 32#define GET_REGINFO_MC_DESC33#include "BPFGenRegisterInfo.inc"34 35using namespace llvm;36 37static MCInstrInfo *createBPFMCInstrInfo() {38 MCInstrInfo *X = new MCInstrInfo();39 InitBPFMCInstrInfo(X);40 return X;41}42 43static MCRegisterInfo *createBPFMCRegisterInfo(const Triple &TT) {44 MCRegisterInfo *X = new MCRegisterInfo();45 InitBPFMCRegisterInfo(X, BPF::R11 /* RAReg doesn't exist */);46 return X;47}48 49static MCSubtargetInfo *createBPFMCSubtargetInfo(const Triple &TT,50 StringRef CPU, StringRef FS) {51 return createBPFMCSubtargetInfoImpl(TT, CPU, /*TuneCPU*/ CPU, FS);52}53 54static MCStreamer *55createBPFMCStreamer(const Triple &T, MCContext &Ctx,56 std::unique_ptr<MCAsmBackend> &&MAB,57 std::unique_ptr<MCObjectWriter> &&OW,58 std::unique_ptr<MCCodeEmitter> &&Emitter) {59 return createELFStreamer(Ctx, std::move(MAB), std::move(OW),60 std::move(Emitter));61}62 63static MCInstPrinter *createBPFMCInstPrinter(const Triple &T,64 unsigned SyntaxVariant,65 const MCAsmInfo &MAI,66 const MCInstrInfo &MII,67 const MCRegisterInfo &MRI) {68 if (SyntaxVariant == 0)69 return new BPFInstPrinter(MAI, MII, MRI);70 return nullptr;71}72 73namespace {74 75class BPFMCInstrAnalysis : public MCInstrAnalysis {76public:77 explicit BPFMCInstrAnalysis(const MCInstrInfo *Info)78 : MCInstrAnalysis(Info) {}79 80 bool evaluateBranch(const MCInst &Inst, uint64_t Addr, uint64_t Size,81 uint64_t &Target) const override {82 // The target is the 3rd operand of cond inst and the 1st of uncond inst.83 int32_t Imm;84 if (isConditionalBranch(Inst)) {85 if (Inst.getOpcode() == BPF::JCOND)86 Imm = (short)Inst.getOperand(0).getImm();87 else88 Imm = (short)Inst.getOperand(2).getImm();89 } else if (isUnconditionalBranch(Inst)) {90 if (Inst.getOpcode() == BPF::JMP)91 Imm = (short)Inst.getOperand(0).getImm();92 else93 Imm = (int)Inst.getOperand(0).getImm();94 } else95 return false;96 97 Target = Addr + Size + Imm * Size;98 return true;99 }100};101 102} // end anonymous namespace103 104static MCInstrAnalysis *createBPFInstrAnalysis(const MCInstrInfo *Info) {105 return new BPFMCInstrAnalysis(Info);106}107 108extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void LLVMInitializeBPFTargetMC() {109 for (Target *T :110 {&getTheBPFleTarget(), &getTheBPFbeTarget(), &getTheBPFTarget()}) {111 // Register the MC asm info.112 RegisterMCAsmInfo<BPFMCAsmInfo> X(*T);113 114 // Register the MC instruction info.115 TargetRegistry::RegisterMCInstrInfo(*T, createBPFMCInstrInfo);116 117 // Register the MC register info.118 TargetRegistry::RegisterMCRegInfo(*T, createBPFMCRegisterInfo);119 120 // Register the MC subtarget info.121 TargetRegistry::RegisterMCSubtargetInfo(*T,122 createBPFMCSubtargetInfo);123 124 // Register the object streamer125 TargetRegistry::RegisterELFStreamer(*T, createBPFMCStreamer);126 127 // Register the MCInstPrinter.128 TargetRegistry::RegisterMCInstPrinter(*T, createBPFMCInstPrinter);129 130 // Register the MC instruction analyzer.131 TargetRegistry::RegisterMCInstrAnalysis(*T, createBPFInstrAnalysis);132 }133 134 // Register the MC code emitter135 TargetRegistry::RegisterMCCodeEmitter(getTheBPFleTarget(),136 createBPFMCCodeEmitter);137 TargetRegistry::RegisterMCCodeEmitter(getTheBPFbeTarget(),138 createBPFbeMCCodeEmitter);139 140 // Register the ASM Backend141 TargetRegistry::RegisterMCAsmBackend(getTheBPFleTarget(),142 createBPFAsmBackend);143 TargetRegistry::RegisterMCAsmBackend(getTheBPFbeTarget(),144 createBPFbeAsmBackend);145 146 if (sys::IsLittleEndianHost) {147 TargetRegistry::RegisterMCCodeEmitter(getTheBPFTarget(),148 createBPFMCCodeEmitter);149 TargetRegistry::RegisterMCAsmBackend(getTheBPFTarget(),150 createBPFAsmBackend);151 } else {152 TargetRegistry::RegisterMCCodeEmitter(getTheBPFTarget(),153 createBPFbeMCCodeEmitter);154 TargetRegistry::RegisterMCAsmBackend(getTheBPFTarget(),155 createBPFbeAsmBackend);156 }157}158