AVRDisassembler.cpp
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//===- AVRDisassembler.cpp - Disassembler for AVR ---------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is part of the AVR Disassembler.
//
//===----------------------------------------------------------------------===//
#include "AVR.h"
#include "AVRRegisterInfo.h"
#include "AVRSubtarget.h"
#include "MCTargetDesc/AVRMCTargetDesc.h"
#include "TargetInfo/AVRTargetInfo.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDisassembler/MCDisassembler.h"
#include "llvm/MC/MCFixedLenDisassembler.h"
#include "llvm/MC/MCInst.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
#define DEBUG_TYPE "avr-disassembler"
typedef MCDisassembler::DecodeStatus DecodeStatus;
namespace {
/// A disassembler class for AVR.
class AVRDisassembler : public MCDisassembler {
public:
AVRDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx)
: MCDisassembler(STI, Ctx) {}
virtual ~AVRDisassembler() {}
DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
ArrayRef<uint8_t> Bytes, uint64_t Address,
raw_ostream &CStream) const override;
};
}
static MCDisassembler *createAVRDisassembler(const Target &T,
const MCSubtargetInfo &STI,
MCContext &Ctx) {
return new AVRDisassembler(STI, Ctx);
}
extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeAVRDisassembler() {
// Register the disassembler.
TargetRegistry::RegisterMCDisassembler(getTheAVRTarget(),
createAVRDisassembler);
}
static DecodeStatus DecodeGPR8RegisterClass(MCInst &Inst, unsigned RegNo,
uint64_t Address, const void *Decoder) {
return MCDisassembler::Success;
}
static DecodeStatus DecodeLD8RegisterClass(MCInst &Inst, unsigned RegNo,
uint64_t Address, const void *Decoder) {
return MCDisassembler::Success;
}
static DecodeStatus DecodePTRREGSRegisterClass(MCInst &Inst, unsigned RegNo,
uint64_t Address, const void *Decoder) {
return MCDisassembler::Success;
}
#include "AVRGenDisassemblerTables.inc"
static DecodeStatus readInstruction16(ArrayRef<uint8_t> Bytes, uint64_t Address,
uint64_t &Size, uint32_t &Insn) {
if (Bytes.size() < 2) {
Size = 0;
return MCDisassembler::Fail;
}
Size = 2;
Insn = (Bytes[0] << 0) | (Bytes[1] << 8);
return MCDisassembler::Success;
}
static DecodeStatus readInstruction32(ArrayRef<uint8_t> Bytes, uint64_t Address,
uint64_t &Size, uint32_t &Insn) {
if (Bytes.size() < 4) {
Size = 0;
return MCDisassembler::Fail;
}
Size = 4;
Insn = (Bytes[0] << 0) | (Bytes[1] << 8) | (Bytes[2] << 16) | (Bytes[3] << 24);
return MCDisassembler::Success;
}
static const uint8_t *getDecoderTable(uint64_t Size) {
switch (Size) {
case 2: return DecoderTable16;
case 4: return DecoderTable32;
default: llvm_unreachable("instructions must be 16 or 32-bits");
}
}
DecodeStatus AVRDisassembler::getInstruction(MCInst &Instr, uint64_t &Size,
ArrayRef<uint8_t> Bytes,
uint64_t Address,
raw_ostream &CStream) const {
uint32_t Insn;
DecodeStatus Result;
// Try decode a 16-bit instruction.
{
Result = readInstruction16(Bytes, Address, Size, Insn);
if (Result == MCDisassembler::Fail) return MCDisassembler::Fail;
// Try to auto-decode a 16-bit instruction.
Result = decodeInstruction(getDecoderTable(Size), Instr,
Insn, Address, this, STI);
if (Result != MCDisassembler::Fail)
return Result;
}
// Try decode a 32-bit instruction.
{
Result = readInstruction32(Bytes, Address, Size, Insn);
if (Result == MCDisassembler::Fail) return MCDisassembler::Fail;
Result = decodeInstruction(getDecoderTable(Size), Instr, Insn,
Address, this, STI);
if (Result != MCDisassembler::Fail) {
return Result;
}
return MCDisassembler::Fail;
}
}
typedef DecodeStatus (*DecodeFunc)(MCInst &MI, unsigned insn, uint64_t Address,
const void *Decoder);