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//===-- XtensaDisassembler.cpp - Disassembler for Xtensa ------------------===//
//
// The LLVM Compiler Infrastructure
//
// 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 implements the XtensaDisassembler class.
//
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/XtensaMCTargetDesc.h"
#include "TargetInfo/XtensaTargetInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDecoderOps.h"
#include "llvm/MC/MCDisassembler/MCDisassembler.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Support/Endian.h"
using namespace llvm;
#define DEBUG_TYPE "Xtensa-disassembler"
using DecodeStatus = MCDisassembler::DecodeStatus;
namespace {
class XtensaDisassembler : public MCDisassembler {
bool IsLittleEndian;
public:
XtensaDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx, bool isLE)
: MCDisassembler(STI, Ctx), IsLittleEndian(isLE) {}
bool hasDensity() const {
return STI.hasFeature(Xtensa::FeatureDensity);
}
DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
ArrayRef<uint8_t> Bytes, uint64_t Address,
raw_ostream &CStream) const override;
};
} // end anonymous namespace
static MCDisassembler *createXtensaDisassembler(const Target &T,
const MCSubtargetInfo &STI,
MCContext &Ctx) {
return new XtensaDisassembler(STI, Ctx, true);
}
extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeXtensaDisassembler() {
TargetRegistry::RegisterMCDisassembler(getTheXtensaTarget(),
createXtensaDisassembler);
}
static const unsigned ARDecoderTable[] = {
Xtensa::A0, Xtensa::SP, Xtensa::A2, Xtensa::A3, Xtensa::A4, Xtensa::A5,
Xtensa::A6, Xtensa::A7, Xtensa::A8, Xtensa::A9, Xtensa::A10, Xtensa::A11,
Xtensa::A12, Xtensa::A13, Xtensa::A14, Xtensa::A15};
static DecodeStatus DecodeARRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
if (RegNo >= std::size(ARDecoderTable))
return MCDisassembler::Fail;
unsigned Reg = ARDecoderTable[RegNo];
Inst.addOperand(MCOperand::createReg(Reg));
return MCDisassembler::Success;
}
static const unsigned SRDecoderTable[] = {Xtensa::SAR, 3};
static DecodeStatus DecodeSRRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
if (RegNo > 255)
return MCDisassembler::Fail;
for (unsigned i = 0; i < std::size(SRDecoderTable); i += 2) {
if (SRDecoderTable[i + 1] == RegNo) {
unsigned Reg = SRDecoderTable[i];
Inst.addOperand(MCOperand::createReg(Reg));
return MCDisassembler::Success;
}
}
return MCDisassembler::Fail;
}
static bool tryAddingSymbolicOperand(int64_t Value, bool isBranch,
uint64_t Address, uint64_t Offset,
uint64_t InstSize, MCInst &MI,
const void *Decoder) {
const MCDisassembler *Dis = static_cast<const MCDisassembler *>(Decoder);
return Dis->tryAddingSymbolicOperand(MI, Value, Address, isBranch, Offset, /*OpSize=*/0,
InstSize);
}
static DecodeStatus decodeCallOperand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<18>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(SignExtend64<20>(Imm << 2)));
return MCDisassembler::Success;
}
static DecodeStatus decodeJumpOperand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<18>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(SignExtend64<18>(Imm)));
return MCDisassembler::Success;
}
static DecodeStatus decodeBranchOperand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
switch (Inst.getOpcode()) {
case Xtensa::BEQZ:
case Xtensa::BGEZ:
case Xtensa::BLTZ:
case Xtensa::BNEZ:
assert(isUInt<12>(Imm) && "Invalid immediate");
if (!tryAddingSymbolicOperand(SignExtend64<12>(Imm) + 4 + Address, true,
Address, 0, 3, Inst, Decoder))
Inst.addOperand(MCOperand::createImm(SignExtend64<12>(Imm)));
break;
default:
assert(isUInt<8>(Imm) && "Invalid immediate");
if (!tryAddingSymbolicOperand(SignExtend64<8>(Imm) + 4 + Address, true,
Address, 0, 3, Inst, Decoder))
Inst.addOperand(MCOperand::createImm(SignExtend64<8>(Imm)));
}
return MCDisassembler::Success;
}
static DecodeStatus decodeL32ROperand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<16>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(
SignExtend64<17>((Imm << 2) + 0x40000 + (Address & 0x3))));
return MCDisassembler::Success;
}
static DecodeStatus decodeImm8Operand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<8>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(SignExtend64<8>(Imm)));
return MCDisassembler::Success;
}
static DecodeStatus decodeImm8_sh8Operand(MCInst &Inst, uint64_t Imm,
int64_t Address,
const void *Decoder) {
assert(isUInt<8>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(SignExtend64<16>(Imm << 8)));
return MCDisassembler::Success;
}
static DecodeStatus decodeImm12Operand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<12>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(SignExtend64<12>(Imm)));
return MCDisassembler::Success;
}
static DecodeStatus decodeUimm4Operand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<4>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(Imm));
return MCDisassembler::Success;
}
static DecodeStatus decodeUimm5Operand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<5>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(Imm));
return MCDisassembler::Success;
}
static DecodeStatus decodeImm1_16Operand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<4>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(Imm + 1));
return MCDisassembler::Success;
}
static DecodeStatus decodeShimm1_31Operand(MCInst &Inst, uint64_t Imm,
int64_t Address,
const void *Decoder) {
assert(isUInt<5>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(32 - Imm));
return MCDisassembler::Success;
}
static int64_t TableB4const[16] = {-1, 1, 2, 3, 4, 5, 6, 7,
8, 10, 12, 16, 32, 64, 128, 256};
static DecodeStatus decodeB4constOperand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<4>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(TableB4const[Imm]));
return MCDisassembler::Success;
}
static int64_t TableB4constu[16] = {32768, 65536, 2, 3, 4, 5, 6, 7,
8, 10, 12, 16, 32, 64, 128, 256};
static DecodeStatus decodeB4constuOperand(MCInst &Inst, uint64_t Imm,
int64_t Address,
const void *Decoder) {
assert(isUInt<4>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(TableB4constu[Imm]));
return MCDisassembler::Success;
}
static DecodeStatus decodeMem8Operand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<12>(Imm) && "Invalid immediate");
DecodeARRegisterClass(Inst, Imm & 0xf, Address, Decoder);
Inst.addOperand(MCOperand::createImm((Imm >> 4) & 0xff));
return MCDisassembler::Success;
}
static DecodeStatus decodeMem16Operand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<12>(Imm) && "Invalid immediate");
DecodeARRegisterClass(Inst, Imm & 0xf, Address, Decoder);
Inst.addOperand(MCOperand::createImm((Imm >> 3) & 0x1fe));
return MCDisassembler::Success;
}
static DecodeStatus decodeMem32Operand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<12>(Imm) && "Invalid immediate");
DecodeARRegisterClass(Inst, Imm & 0xf, Address, Decoder);
Inst.addOperand(MCOperand::createImm((Imm >> 2) & 0x3fc));
return MCDisassembler::Success;
}
/// Read three bytes from the ArrayRef and return 24 bit data
static DecodeStatus readInstruction24(ArrayRef<uint8_t> Bytes, uint64_t Address,
uint64_t &Size, uint32_t &Insn,
bool IsLittleEndian) {
// We want to read exactly 3 Bytes of data.
if (Bytes.size() < 3) {
Size = 0;
return MCDisassembler::Fail;
}
if (!IsLittleEndian) {
report_fatal_error("Big-endian mode currently is not supported!");
} else {
Insn = (Bytes[2] << 16) | (Bytes[1] << 8) | (Bytes[0] << 0);
}
Size = 3;
return MCDisassembler::Success;
}
#include "XtensaGenDisassemblerTables.inc"
DecodeStatus XtensaDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
ArrayRef<uint8_t> Bytes,
uint64_t Address,
raw_ostream &CS) const {
uint32_t Insn;
DecodeStatus Result;
Result = readInstruction24(Bytes, Address, Size, Insn, IsLittleEndian);
if (Result == MCDisassembler::Fail)
return MCDisassembler::Fail;
LLVM_DEBUG(dbgs() << "Trying Xtensa 24-bit instruction table :\n");
Result = decodeInstruction(DecoderTable24, MI, Insn, Address, this, STI);
return Result;
}
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