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-exception
6//
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/Support/Host.h"
22#include "llvm/Support/TargetRegistry.h"
23
24#define GET_INSTRINFO_MC_DESC
25#include "BPFGenInstrInfo.inc"
26
27#define GET_SUBTARGETINFO_MC_DESC
28#include "BPFGenSubtargetInfo.inc"
29
30#define GET_REGINFO_MC_DESC
31#include "BPFGenRegisterInfo.inc"
32
33using namespace llvm;
34
35static MCInstrInfo *createBPFMCInstrInfo() {
36  MCInstrInfo *X = new MCInstrInfo();
37  InitBPFMCInstrInfo(X);
38  return X;
39}
40
41static MCRegisterInfo *createBPFMCRegisterInfo(const Triple &TT) {
42  MCRegisterInfo *X = new MCRegisterInfo();
43  InitBPFMCRegisterInfo(X, BPF::R11 /* RAReg doesn't exist */);
44  return X;
45}
46
47static MCSubtargetInfo *createBPFMCSubtargetInfo(const Triple &TT,
48                                                 StringRef CPU, StringRef FS) {
49  return createBPFMCSubtargetInfoImpl(TT, CPU, FS);
50}
51
52static MCStreamer *createBPFMCStreamer(const Triple &T, MCContext &Ctx,
53                                       std::unique_ptr<MCAsmBackend> &&MAB,
54                                       std::unique_ptr<MCObjectWriter> &&OW,
55                                       std::unique_ptr<MCCodeEmitter> &&Emitter,
56                                       bool RelaxAll) {
57  return createELFStreamer(Ctx, std::move(MAB), std::move(OW), std::move(Emitter),
58                           RelaxAll);
59}
60
61static MCInstPrinter *createBPFMCInstPrinter(const Triple &T,
62                                             unsigned SyntaxVariant,
63                                             const MCAsmInfo &MAI,
64                                             const MCInstrInfo &MII,
65                                             const MCRegisterInfo &MRI) {
66  if (SyntaxVariant == 0)
67    return new BPFInstPrinter(MAI, MII, MRI);
68  return nullptr;
69}
70
71namespace {
72
73class BPFMCInstrAnalysis : public MCInstrAnalysis {
74public:
75  explicit BPFMCInstrAnalysis(const MCInstrInfo *Info)
76      : MCInstrAnalysis(Info) {}
77
78  bool evaluateBranch(const MCInst &Inst, uint64_t Addr, uint64_t Size,
79                      uint64_t &Target) const override {
80    // The target is the 3rd operand of cond inst and the 1st of uncond inst.
81    int16_t Imm;
82    if (isConditionalBranch(Inst)) {
83      Imm = Inst.getOperand(2).getImm();
84    } else if (isUnconditionalBranch(Inst))
85      Imm = Inst.getOperand(0).getImm();
86    else
87      return false;
88
89    Target = Addr + Size + Imm * Size;
90    return true;
91  }
92};
93
94} // end anonymous namespace
95
96static MCInstrAnalysis *createBPFInstrAnalysis(const MCInstrInfo *Info) {
97  return new BPFMCInstrAnalysis(Info);
98}
99
100extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeBPFTargetMC() {
101  for (Target *T :
102       {&getTheBPFleTarget(), &getTheBPFbeTarget(), &getTheBPFTarget()}) {
103    // Register the MC asm info.
104    RegisterMCAsmInfo<BPFMCAsmInfo> X(*T);
105
106    // Register the MC instruction info.
107    TargetRegistry::RegisterMCInstrInfo(*T, createBPFMCInstrInfo);
108
109    // Register the MC register info.
110    TargetRegistry::RegisterMCRegInfo(*T, createBPFMCRegisterInfo);
111
112    // Register the MC subtarget info.
113    TargetRegistry::RegisterMCSubtargetInfo(*T,
114                                            createBPFMCSubtargetInfo);
115
116    // Register the object streamer
117    TargetRegistry::RegisterELFStreamer(*T, createBPFMCStreamer);
118
119    // Register the MCInstPrinter.
120    TargetRegistry::RegisterMCInstPrinter(*T, createBPFMCInstPrinter);
121
122    // Register the MC instruction analyzer.
123    TargetRegistry::RegisterMCInstrAnalysis(*T, createBPFInstrAnalysis);
124  }
125
126  // Register the MC code emitter
127  TargetRegistry::RegisterMCCodeEmitter(getTheBPFleTarget(),
128                                        createBPFMCCodeEmitter);
129  TargetRegistry::RegisterMCCodeEmitter(getTheBPFbeTarget(),
130                                        createBPFbeMCCodeEmitter);
131
132  // Register the ASM Backend
133  TargetRegistry::RegisterMCAsmBackend(getTheBPFleTarget(),
134                                       createBPFAsmBackend);
135  TargetRegistry::RegisterMCAsmBackend(getTheBPFbeTarget(),
136                                       createBPFbeAsmBackend);
137
138  if (sys::IsLittleEndianHost) {
139    TargetRegistry::RegisterMCCodeEmitter(getTheBPFTarget(),
140                                          createBPFMCCodeEmitter);
141    TargetRegistry::RegisterMCAsmBackend(getTheBPFTarget(),
142                                         createBPFAsmBackend);
143  } else {
144    TargetRegistry::RegisterMCCodeEmitter(getTheBPFTarget(),
145                                          createBPFbeMCCodeEmitter);
146    TargetRegistry::RegisterMCAsmBackend(getTheBPFTarget(),
147                                         createBPFbeAsmBackend);
148  }
149
150}
151