//===------ PPCDisassembler.cpp - Disassembler for PowerPC ------*- 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
//
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/PPCMCTargetDesc.h"
#include "TargetInfo/PowerPCTargetInfo.h"
#include "llvm/MC/MCDisassembler/MCDisassembler.h"
#include "llvm/MC/MCFixedLenDisassembler.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
DEFINE_PPC_REGCLASSES;
#define DEBUG_TYPE "ppc-disassembler"
typedef MCDisassembler::DecodeStatus DecodeStatus;
namespace {
class PPCDisassembler : public MCDisassembler {
bool IsLittleEndian;
public:
PPCDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx,
bool IsLittleEndian)
: MCDisassembler(STI, Ctx), IsLittleEndian(IsLittleEndian) {}
DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
ArrayRef<uint8_t> Bytes, uint64_t Address,
raw_ostream &CStream) const override;
};
} // end anonymous namespace
static MCDisassembler *createPPCDisassembler(const Target &T,
const MCSubtargetInfo &STI,
MCContext &Ctx) {
return new PPCDisassembler(STI, Ctx, /*IsLittleEndian=*/false);
}
static MCDisassembler *createPPCLEDisassembler(const Target &T,
const MCSubtargetInfo &STI,
MCContext &Ctx) {
return new PPCDisassembler(STI, Ctx, /*IsLittleEndian=*/true);
}
extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializePowerPCDisassembler() {
// Register the disassembler for each target.
TargetRegistry::RegisterMCDisassembler(getThePPC32Target(),
createPPCDisassembler);
TargetRegistry::RegisterMCDisassembler(getThePPC64Target(),
createPPCDisassembler);
TargetRegistry::RegisterMCDisassembler(getThePPC64LETarget(),
createPPCLEDisassembler);
}
static DecodeStatus decodeCondBrTarget(MCInst &Inst, unsigned Imm,
uint64_t /*Address*/,
const void * /*Decoder*/) {
Inst.addOperand(MCOperand::createImm(SignExtend32<14>(Imm)));
return MCDisassembler::Success;
}
static DecodeStatus decodeDirectBrTarget(MCInst &Inst, unsigned Imm,
uint64_t /*Address*/,
const void * /*Decoder*/) {
int32_t Offset = SignExtend32<24>(Imm);
Inst.addOperand(MCOperand::createImm(Offset));
return MCDisassembler::Success;
}
// FIXME: These can be generated by TableGen from the existing register
// encoding values!
template <std::size_t N>
static DecodeStatus decodeRegisterClass(MCInst &Inst, uint64_t RegNo,
const MCPhysReg (&Regs)[N]) {
assert(RegNo < N && "Invalid register number");
Inst.addOperand(MCOperand::createReg(Regs[RegNo]));
return MCDisassembler::Success;
}
static DecodeStatus DecodeCRRCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, CRRegs);
}
static DecodeStatus DecodeCRBITRCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, CRBITRegs);
}
static DecodeStatus DecodeF4RCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, FRegs);
}
static DecodeStatus DecodeF8RCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, FRegs);
}
static DecodeStatus DecodeVFRCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, VFRegs);
}
static DecodeStatus DecodeVRRCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, VRegs);
}
static DecodeStatus DecodeVSRCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, VSRegs);
}
static DecodeStatus DecodeVSFRCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, VSFRegs);
}
static DecodeStatus DecodeVSSRCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, VSSRegs);
}
static DecodeStatus DecodeGPRCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, RRegs);
}
static DecodeStatus DecodeGPRC_NOR0RegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, RRegsNoR0);
}
static DecodeStatus DecodeG8RCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, XRegs);
}
static DecodeStatus DecodeG8RC_NOX0RegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, XRegsNoX0);
}
#define DecodePointerLikeRegClass0 DecodeGPRCRegisterClass
#define DecodePointerLikeRegClass1 DecodeGPRC_NOR0RegisterClass
static DecodeStatus DecodeQFRCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, QFRegs);
}
static DecodeStatus DecodeSPERCRegisterClass(MCInst &Inst, uint64_t RegNo,
uint64_t Address,
const void *Decoder) {
return decodeRegisterClass(Inst, RegNo, SPERegs);
}
#define DecodeQSRCRegisterClass DecodeQFRCRegisterClass
#define DecodeQBRCRegisterClass DecodeQFRCRegisterClass
template<unsigned N>
static DecodeStatus decodeUImmOperand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<N>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(Imm));
return MCDisassembler::Success;
}
template<unsigned N>
static DecodeStatus decodeSImmOperand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
assert(isUInt<N>(Imm) && "Invalid immediate");
Inst.addOperand(MCOperand::createImm(SignExtend64<N>(Imm)));
return MCDisassembler::Success;
}
static DecodeStatus decodeImmZeroOperand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
if (Imm != 0)
return MCDisassembler::Fail;
Inst.addOperand(MCOperand::createImm(Imm));
return MCDisassembler::Success;
}
static DecodeStatus decodeMemRIOperands(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
// Decode the memri field (imm, reg), which has the low 16-bits as the
// displacement and the next 5 bits as the register #.
uint64_t Base = Imm >> 16;
uint64_t Disp = Imm & 0xFFFF;
assert(Base < 32 && "Invalid base register");
switch (Inst.getOpcode()) {
default: break;
case PPC::LBZU:
case PPC::LHAU:
case PPC::LHZU:
case PPC::LWZU:
case PPC::LFSU:
case PPC::LFDU:
// Add the tied output operand.
Inst.addOperand(MCOperand::createReg(RRegsNoR0[Base]));
break;
case PPC::STBU:
case PPC::STHU:
case PPC::STWU:
case PPC::STFSU:
case PPC::STFDU:
Inst.insert(Inst.begin(), MCOperand::createReg(RRegsNoR0[Base]));
break;
}
Inst.addOperand(MCOperand::createImm(SignExtend64<16>(Disp)));
Inst.addOperand(MCOperand::createReg(RRegsNoR0[Base]));
return MCDisassembler::Success;
}
static DecodeStatus decodeMemRIXOperands(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
// Decode the memrix field (imm, reg), which has the low 14-bits as the
// displacement and the next 5 bits as the register #.
uint64_t Base = Imm >> 14;
uint64_t Disp = Imm & 0x3FFF;
assert(Base < 32 && "Invalid base register");
if (Inst.getOpcode() == PPC::LDU)
// Add the tied output operand.
Inst.addOperand(MCOperand::createReg(RRegsNoR0[Base]));
else if (Inst.getOpcode() == PPC::STDU)
Inst.insert(Inst.begin(), MCOperand::createReg(RRegsNoR0[Base]));
Inst.addOperand(MCOperand::createImm(SignExtend64<16>(Disp << 2)));
Inst.addOperand(MCOperand::createReg(RRegsNoR0[Base]));
return MCDisassembler::Success;
}
static DecodeStatus decodeMemRIX16Operands(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
// Decode the memrix16 field (imm, reg), which has the low 12-bits as the
// displacement with 16-byte aligned, and the next 5 bits as the register #.
uint64_t Base = Imm >> 12;
uint64_t Disp = Imm & 0xFFF;
assert(Base < 32 && "Invalid base register");
Inst.addOperand(MCOperand::createImm(SignExtend64<16>(Disp << 4)));
Inst.addOperand(MCOperand::createReg(RRegsNoR0[Base]));
return MCDisassembler::Success;
}
static DecodeStatus decodeMemRI34PCRelOperands(MCInst &Inst, uint64_t Imm,
int64_t Address,
const void *Decoder) {
// Decode the memri34_pcrel field (imm, reg), which has the low 34-bits as the
// displacement, and the next 5 bits as an immediate 0.
uint64_t Base = Imm >> 34;
uint64_t Disp = Imm & 0x3FFFFFFFFUL;
assert(Base < 32 && "Invalid base register");
Inst.addOperand(MCOperand::createImm(SignExtend64<34>(Disp)));
return decodeImmZeroOperand(Inst, Base, Address, Decoder);
}
static DecodeStatus decodeMemRI34Operands(MCInst &Inst, uint64_t Imm,
int64_t Address,
const void *Decoder) {
// Decode the memri34 field (imm, reg), which has the low 34-bits as the
// displacement, and the next 5 bits as the register #.
uint64_t Base = Imm >> 34;
uint64_t Disp = Imm & 0x3FFFFFFFFUL;
assert(Base < 32 && "Invalid base register");
Inst.addOperand(MCOperand::createImm(SignExtend64<34>(Disp)));
Inst.addOperand(MCOperand::createReg(RRegsNoR0[Base]));
return MCDisassembler::Success;
}
static DecodeStatus decodeSPE8Operands(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
// Decode the spe8disp field (imm, reg), which has the low 5-bits as the
// displacement with 8-byte aligned, and the next 5 bits as the register #.
uint64_t Base = Imm >> 5;
uint64_t Disp = Imm & 0x1F;
assert(Base < 32 && "Invalid base register");
Inst.addOperand(MCOperand::createImm(Disp << 3));
Inst.addOperand(MCOperand::createReg(RRegsNoR0[Base]));
return MCDisassembler::Success;
}
static DecodeStatus decodeSPE4Operands(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
// Decode the spe4disp field (imm, reg), which has the low 5-bits as the
// displacement with 4-byte aligned, and the next 5 bits as the register #.
uint64_t Base = Imm >> 5;
uint64_t Disp = Imm & 0x1F;
assert(Base < 32 && "Invalid base register");
Inst.addOperand(MCOperand::createImm(Disp << 2));
Inst.addOperand(MCOperand::createReg(RRegsNoR0[Base]));
return MCDisassembler::Success;
}
static DecodeStatus decodeSPE2Operands(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
// Decode the spe2disp field (imm, reg), which has the low 5-bits as the
// displacement with 2-byte aligned, and the next 5 bits as the register #.
uint64_t Base = Imm >> 5;
uint64_t Disp = Imm & 0x1F;
assert(Base < 32 && "Invalid base register");
Inst.addOperand(MCOperand::createImm(Disp << 1));
Inst.addOperand(MCOperand::createReg(RRegsNoR0[Base]));
return MCDisassembler::Success;
}
static DecodeStatus decodeCRBitMOperand(MCInst &Inst, uint64_t Imm,
int64_t Address, const void *Decoder) {
// The cr bit encoding is 0x80 >> cr_reg_num.
unsigned Zeros = countTrailingZeros(Imm);
assert(Zeros < 8 && "Invalid CR bit value");
Inst.addOperand(MCOperand::createReg(CRRegs[7 - Zeros]));
return MCDisassembler::Success;
}
#include "PPCGenDisassemblerTables.inc"
DecodeStatus PPCDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
ArrayRef<uint8_t> Bytes,
uint64_t Address,
raw_ostream &CS) const {
auto *ReadFunc = IsLittleEndian ? support::endian::read32le
: support::endian::read32be;
// If this is an 8-byte prefixed instruction, handle it here.
// Note: prefixed instructions aren't technically 8-byte entities - the prefix
// appears in memory at an address 4 bytes prior to that of the base
// instruction regardless of endianness. So we read the two pieces and
// rebuild the 8-byte instruction.
// TODO: In this function we call decodeInstruction several times with
// different decoder tables. It may be possible to only call once by
// looking at the top 6 bits of the instruction.
if (STI.getFeatureBits()[PPC::FeaturePrefixInstrs] && Bytes.size() >= 8) {
uint32_t Prefix = ReadFunc(Bytes.data());
uint32_t BaseInst = ReadFunc(Bytes.data() + 4);
uint64_t Inst = BaseInst | (uint64_t)Prefix << 32;
DecodeStatus result = decodeInstruction(DecoderTable64, MI, Inst, Address,
this, STI);
if (result != MCDisassembler::Fail) {
Size = 8;
return result;
}
}
// Get the four bytes of the instruction.
Size = 4;
if (Bytes.size() < 4) {
Size = 0;
return MCDisassembler::Fail;
}
// Read the instruction in the proper endianness.
uint64_t Inst = ReadFunc(Bytes.data());
if (STI.getFeatureBits()[PPC::FeatureQPX]) {
DecodeStatus result =
decodeInstruction(DecoderTableQPX32, MI, Inst, Address, this, STI);
if (result != MCDisassembler::Fail)
return result;
} else if (STI.getFeatureBits()[PPC::FeatureSPE]) {
DecodeStatus result =
decodeInstruction(DecoderTableSPE32, MI, Inst, Address, this, STI);
if (result != MCDisassembler::Fail)
return result;
}
return decodeInstruction(DecoderTable32, MI, Inst, Address, this, STI);
}
