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llvm-project/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp

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//===-- X86Disassembler.cpp - Disassembler for x86 and x86_64 -------------===//
//
// 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 X86 Disassembler.
// It contains code to translate the data produced by the decoder into
// MCInsts.
//
//
// The X86 disassembler is a table-driven disassembler for the 16-, 32-, and
// 64-bit X86 instruction sets. The main decode sequence for an assembly
// instruction in this disassembler is:
//
// 1. Read the prefix bytes and determine the attributes of the instruction.
// These attributes, recorded in enum attributeBits
// (X86DisassemblerDecoderCommon.h), form a bitmask. The table CONTEXTS_SYM
// provides a mapping from bitmasks to contexts, which are represented by
// enum InstructionContext (ibid.).
//
// 2. Read the opcode, and determine what kind of opcode it is. The
// disassembler distinguishes four kinds of opcodes, which are enumerated in
// OpcodeType (X86DisassemblerDecoderCommon.h): one-byte (0xnn), two-byte
// (0x0f 0xnn), three-byte-38 (0x0f 0x38 0xnn), or three-byte-3a
// (0x0f 0x3a 0xnn). Mandatory prefixes are treated as part of the context.
//
// 3. Depending on the opcode type, look in one of four ClassDecision structures
// (X86DisassemblerDecoderCommon.h). Use the opcode class to determine which
// OpcodeDecision (ibid.) to look the opcode in. Look up the opcode, to get
// a ModRMDecision (ibid.).
//
// 4. Some instructions, such as escape opcodes or extended opcodes, or even
// instructions that have ModRM*Reg / ModRM*Mem forms in LLVM, need the
// ModR/M byte to complete decode. The ModRMDecision's type is an entry from
// ModRMDecisionType (X86DisassemblerDecoderCommon.h) that indicates if the
// ModR/M byte is required and how to interpret it.
//
// 5. After resolving the ModRMDecision, the disassembler has a unique ID
// of type InstrUID (X86DisassemblerDecoderCommon.h). Looking this ID up in
// INSTRUCTIONS_SYM yields the name of the instruction and the encodings and
// meanings of its operands.
//
// 6. For each operand, its encoding is an entry from OperandEncoding
// (X86DisassemblerDecoderCommon.h) and its type is an entry from
// OperandType (ibid.). The encoding indicates how to read it from the
// instruction; the type indicates how to interpret the value once it has
// been read. For example, a register operand could be stored in the R/M
// field of the ModR/M byte, the REG field of the ModR/M byte, or added to
// the main opcode. This is orthogonal from its meaning (an GPR or an XMM
// register, for instance). Given this information, the operands can be
// extracted and interpreted.
//
// 7. As the last step, the disassembler translates the instruction information
// and operands into a format understandable by the client - in this case, an
// MCInst for use by the MC infrastructure.
//
// The disassembler is broken broadly into two parts: the table emitter that
// emits the instruction decode tables discussed above during compilation, and
// the disassembler itself. The table emitter is documented in more detail in
// utils/TableGen/X86DisassemblerEmitter.h.
//
// X86Disassembler.cpp contains the code responsible for step 7, and for
// invoking the decoder to execute steps 1-6.
// X86DisassemblerDecoderCommon.h contains the definitions needed by both the
// table emitter and the disassembler.
// X86DisassemblerDecoder.h contains the public interface of the decoder,
// factored out into C for possible use by other projects.
// X86DisassemblerDecoder.c contains the source code of the decoder, which is
// responsible for steps 1-6.
//
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/X86BaseInfo.h"
#include "MCTargetDesc/X86MCTargetDesc.h"
#include "TargetInfo/X86TargetInfo.h"
#include "X86DisassemblerDecoder.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDisassembler/MCDisassembler.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
using namespace llvm::X86Disassembler;
#define DEBUG_TYPE "x86-disassembler"
void llvm::X86Disassembler::Debug(const char *file, unsigned line,
const char *s) {
dbgs() << file << ":" << line << ": " << s;
}
StringRef llvm::X86Disassembler::GetInstrName(unsigned Opcode,
const void *mii) {
const MCInstrInfo *MII = static_cast<const MCInstrInfo *>(mii);
return MII->getName(Opcode);
}
#define debug(s) LLVM_DEBUG(Debug(__FILE__, __LINE__, s));
namespace llvm {
// Fill-ins to make the compiler happy. These constants are never actually
// assigned; they are just filler to make an automatically-generated switch
// statement work.
namespace X86 {
enum {
BX_SI = 500,
BX_DI = 501,
BP_SI = 502,
BP_DI = 503,
sib = 504,
sib64 = 505
};
}
}
static bool translateInstruction(MCInst &target,
InternalInstruction &source,
const MCDisassembler *Dis);
namespace {
/// Generic disassembler for all X86 platforms. All each platform class should
/// have to do is subclass the constructor, and provide a different
/// disassemblerMode value.
class X86GenericDisassembler : public MCDisassembler {
std::unique_ptr<const MCInstrInfo> MII;
public:
X86GenericDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx,
std::unique_ptr<const MCInstrInfo> MII);
public:
DecodeStatus getInstruction(MCInst &instr, uint64_t &size,
ArrayRef<uint8_t> Bytes, uint64_t Address,
raw_ostream &vStream,
raw_ostream &cStream) const override;
private:
DisassemblerMode fMode;
};
}
X86GenericDisassembler::X86GenericDisassembler(
const MCSubtargetInfo &STI,
MCContext &Ctx,
std::unique_ptr<const MCInstrInfo> MII)
: MCDisassembler(STI, Ctx), MII(std::move(MII)) {
const FeatureBitset &FB = STI.getFeatureBits();
if (FB[X86::Mode16Bit]) {
fMode = MODE_16BIT;
return;
} else if (FB[X86::Mode32Bit]) {
fMode = MODE_32BIT;
return;
} else if (FB[X86::Mode64Bit]) {
fMode = MODE_64BIT;
return;
}
llvm_unreachable("Invalid CPU mode");
}
namespace {
struct Region {
ArrayRef<uint8_t> Bytes;
uint64_t Base;
Region(ArrayRef<uint8_t> Bytes, uint64_t Base) : Bytes(Bytes), Base(Base) {}
};
} // end anonymous namespace
/// A callback function that wraps the readByte method from Region.
///
/// @param Arg - The generic callback parameter. In this case, this should
/// be a pointer to a Region.
/// @param Byte - A pointer to the byte to be read.
/// @param Address - The address to be read.
static int regionReader(const void *Arg, uint8_t *Byte, uint64_t Address) {
auto *R = static_cast<const Region *>(Arg);
ArrayRef<uint8_t> Bytes = R->Bytes;
unsigned Index = Address - R->Base;
if (Bytes.size() <= Index)
return -1;
*Byte = Bytes[Index];
return 0;
}
/// logger - a callback function that wraps the operator<< method from
/// raw_ostream.
///
/// @param arg - The generic callback parameter. This should be a pointe
/// to a raw_ostream.
/// @param log - A string to be logged. logger() adds a newline.
static void logger(void* arg, const char* log) {
if (!arg)
return;
raw_ostream &vStream = *(static_cast<raw_ostream*>(arg));
vStream << log << "\n";
}
//
// Public interface for the disassembler
//
MCDisassembler::DecodeStatus X86GenericDisassembler::getInstruction(
MCInst &Instr, uint64_t &Size, ArrayRef<uint8_t> Bytes, uint64_t Address,
raw_ostream &VStream, raw_ostream &CStream) const {
CommentStream = &CStream;
InternalInstruction InternalInstr;
dlog_t LoggerFn = logger;
if (&VStream == &nulls())
LoggerFn = nullptr; // Disable logging completely if it's going to nulls().
Region R(Bytes, Address);
int Ret = decodeInstruction(&InternalInstr, regionReader, (const void *)&R,
LoggerFn, (void *)&VStream,
(const void *)MII.get(), Address, fMode);
if (Ret) {
Size = InternalInstr.readerCursor - Address;
return Fail;
} else {
Size = InternalInstr.length;
bool Ret = translateInstruction(Instr, InternalInstr, this);
if (!Ret) {
unsigned Flags = X86::IP_NO_PREFIX;
if (InternalInstr.hasAdSize)
Flags |= X86::IP_HAS_AD_SIZE;
if (!InternalInstr.mandatoryPrefix) {
if (InternalInstr.hasOpSize)
Flags |= X86::IP_HAS_OP_SIZE;
if (InternalInstr.repeatPrefix == 0xf2)
Flags |= X86::IP_HAS_REPEAT_NE;
else if (InternalInstr.repeatPrefix == 0xf3 &&
// It should not be 'pause' f3 90
InternalInstr.opcode != 0x90)
Flags |= X86::IP_HAS_REPEAT;
if (InternalInstr.hasLockPrefix)
Flags |= X86::IP_HAS_LOCK;
}
Instr.setFlags(Flags);
}
return (!Ret) ? Success : Fail;
}
}
//
// Private code that translates from struct InternalInstructions to MCInsts.
//
/// translateRegister - Translates an internal register to the appropriate LLVM
/// register, and appends it as an operand to an MCInst.
///
/// @param mcInst - The MCInst to append to.
/// @param reg - The Reg to append.
static void translateRegister(MCInst &mcInst, Reg reg) {
#define ENTRY(x) X86::x,
static constexpr MCPhysReg llvmRegnums[] = {ALL_REGS};
#undef ENTRY
MCPhysReg llvmRegnum = llvmRegnums[reg];
mcInst.addOperand(MCOperand::createReg(llvmRegnum));
}
/// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the
/// immediate Value in the MCInst.
///
/// @param Value - The immediate Value, has had any PC adjustment made by
/// the caller.
/// @param isBranch - If the instruction is a branch instruction
/// @param Address - The starting address of the instruction
/// @param Offset - The byte offset to this immediate in the instruction
/// @param Width - The byte width of this immediate in the instruction
///
/// If the getOpInfo() function was set when setupForSymbolicDisassembly() was
/// called then that function is called to get any symbolic information for the
/// immediate in the instruction using the Address, Offset and Width. If that
/// returns non-zero then the symbolic information it returns is used to create
/// an MCExpr and that is added as an operand to the MCInst. If getOpInfo()
/// returns zero and isBranch is true then a symbol look up for immediate Value
/// is done and if a symbol is found an MCExpr is created with that, else
/// an MCExpr with the immediate Value is created. This function returns true
/// if it adds an operand to the MCInst and false otherwise.
static bool tryAddingSymbolicOperand(int64_t Value, bool isBranch,
uint64_t Address, uint64_t Offset,
uint64_t Width, MCInst &MI,
const MCDisassembler *Dis) {
return Dis->tryAddingSymbolicOperand(MI, Value, Address, isBranch,
Offset, Width);
}
/// tryAddingPcLoadReferenceComment - trys to add a comment as to what is being
/// referenced by a load instruction with the base register that is the rip.
/// These can often be addresses in a literal pool. The Address of the
/// instruction and its immediate Value are used to determine the address
/// being referenced in the literal pool entry. The SymbolLookUp call back will
/// return a pointer to a literal 'C' string if the referenced address is an
/// address into a section with 'C' string literals.
static void tryAddingPcLoadReferenceComment(uint64_t Address, uint64_t Value,
const void *Decoder) {
const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
Dis->tryAddingPcLoadReferenceComment(Value, Address);
}
static const uint8_t segmentRegnums[SEG_OVERRIDE_max] = {
0, // SEG_OVERRIDE_NONE
X86::CS,
X86::SS,
X86::DS,
X86::ES,
X86::FS,
X86::GS
};
/// translateSrcIndex - Appends a source index operand to an MCInst.
///
/// @param mcInst - The MCInst to append to.
/// @param insn - The internal instruction.
static bool translateSrcIndex(MCInst &mcInst, InternalInstruction &insn) {
unsigned baseRegNo;
if (insn.mode == MODE_64BIT)
baseRegNo = insn.hasAdSize ? X86::ESI : X86::RSI;
else if (insn.mode == MODE_32BIT)
baseRegNo = insn.hasAdSize ? X86::SI : X86::ESI;
else {
assert(insn.mode == MODE_16BIT);
baseRegNo = insn.hasAdSize ? X86::ESI : X86::SI;
}
MCOperand baseReg = MCOperand::createReg(baseRegNo);
mcInst.addOperand(baseReg);
MCOperand segmentReg;
segmentReg = MCOperand::createReg(segmentRegnums[insn.segmentOverride]);
mcInst.addOperand(segmentReg);
return false;
}
/// translateDstIndex - Appends a destination index operand to an MCInst.
///
/// @param mcInst - The MCInst to append to.
/// @param insn - The internal instruction.
static bool translateDstIndex(MCInst &mcInst, InternalInstruction &insn) {
unsigned baseRegNo;
if (insn.mode == MODE_64BIT)
baseRegNo = insn.hasAdSize ? X86::EDI : X86::RDI;
else if (insn.mode == MODE_32BIT)
baseRegNo = insn.hasAdSize ? X86::DI : X86::EDI;
else {
assert(insn.mode == MODE_16BIT);
baseRegNo = insn.hasAdSize ? X86::EDI : X86::DI;
}
MCOperand baseReg = MCOperand::createReg(baseRegNo);
mcInst.addOperand(baseReg);
return false;
}
/// translateImmediate - Appends an immediate operand to an MCInst.
///
/// @param mcInst - The MCInst to append to.
/// @param immediate - The immediate value to append.
/// @param operand - The operand, as stored in the descriptor table.
/// @param insn - The internal instruction.
static void translateImmediate(MCInst &mcInst, uint64_t immediate,
const OperandSpecifier &operand,
InternalInstruction &insn,
const MCDisassembler *Dis) {
// Sign-extend the immediate if necessary.
OperandType type = (OperandType)operand.type;
bool isBranch = false;
uint64_t pcrel = 0;
if (type == TYPE_REL) {
isBranch = true;
pcrel = insn.startLocation +
insn.immediateOffset + insn.immediateSize;
switch (operand.encoding) {
default:
break;
case ENCODING_Iv:
switch (insn.displacementSize) {
default:
break;
case 1:
if(immediate & 0x80)
immediate |= ~(0xffull);
break;
case 2:
if(immediate & 0x8000)
immediate |= ~(0xffffull);
break;
case 4:
if(immediate & 0x80000000)
immediate |= ~(0xffffffffull);
break;
case 8:
break;
}
break;
case ENCODING_IB:
if(immediate & 0x80)
immediate |= ~(0xffull);
break;
case ENCODING_IW:
if(immediate & 0x8000)
immediate |= ~(0xffffull);
break;
case ENCODING_ID:
if(immediate & 0x80000000)
immediate |= ~(0xffffffffull);
break;
}
}
// By default sign-extend all X86 immediates based on their encoding.
else if (type == TYPE_IMM) {
switch (operand.encoding) {
default:
break;
case ENCODING_IB:
if(immediate & 0x80)
immediate |= ~(0xffull);
break;
case ENCODING_IW:
if(immediate & 0x8000)
immediate |= ~(0xffffull);
break;
case ENCODING_ID:
if(immediate & 0x80000000)
immediate |= ~(0xffffffffull);
break;
case ENCODING_IO:
break;
}
}
switch (type) {
case TYPE_XMM:
mcInst.addOperand(MCOperand::createReg(X86::XMM0 + (immediate >> 4)));
return;
case TYPE_YMM:
mcInst.addOperand(MCOperand::createReg(X86::YMM0 + (immediate >> 4)));
return;
case TYPE_ZMM:
mcInst.addOperand(MCOperand::createReg(X86::ZMM0 + (immediate >> 4)));
return;
default:
// operand is 64 bits wide. Do nothing.
break;
}
if(!tryAddingSymbolicOperand(immediate + pcrel, isBranch, insn.startLocation,
insn.immediateOffset, insn.immediateSize,
mcInst, Dis))
mcInst.addOperand(MCOperand::createImm(immediate));
if (type == TYPE_MOFFS) {
MCOperand segmentReg;
segmentReg = MCOperand::createReg(segmentRegnums[insn.segmentOverride]);
mcInst.addOperand(segmentReg);
}
}
/// translateRMRegister - Translates a register stored in the R/M field of the
/// ModR/M byte to its LLVM equivalent and appends it to an MCInst.
/// @param mcInst - The MCInst to append to.
/// @param insn - The internal instruction to extract the R/M field
/// from.
/// @return - 0 on success; -1 otherwise
static bool translateRMRegister(MCInst &mcInst,
InternalInstruction &insn) {
if (insn.eaBase == EA_BASE_sib || insn.eaBase == EA_BASE_sib64) {
debug("A R/M register operand may not have a SIB byte");
return true;
}
switch (insn.eaBase) {
default:
debug("Unexpected EA base register");
return true;
case EA_BASE_NONE:
debug("EA_BASE_NONE for ModR/M base");
return true;
#define ENTRY(x) case EA_BASE_##x:
ALL_EA_BASES
#undef ENTRY
debug("A R/M register operand may not have a base; "
"the operand must be a register.");
return true;
#define ENTRY(x) \
case EA_REG_##x: \
mcInst.addOperand(MCOperand::createReg(X86::x)); break;
ALL_REGS
#undef ENTRY
}
return false;
}
/// translateRMMemory - Translates a memory operand stored in the Mod and R/M
/// fields of an internal instruction (and possibly its SIB byte) to a memory
/// operand in LLVM's format, and appends it to an MCInst.
///
/// @param mcInst - The MCInst to append to.
/// @param insn - The instruction to extract Mod, R/M, and SIB fields
/// from.
/// @return - 0 on success; nonzero otherwise
static bool translateRMMemory(MCInst &mcInst, InternalInstruction &insn,
const MCDisassembler *Dis) {
// Addresses in an MCInst are represented as five operands:
// 1. basereg (register) The R/M base, or (if there is a SIB) the
// SIB base
// 2. scaleamount (immediate) 1, or (if there is a SIB) the specified
// scale amount
// 3. indexreg (register) x86_registerNONE, or (if there is a SIB)
// the index (which is multiplied by the
// scale amount)
// 4. displacement (immediate) 0, or the displacement if there is one
// 5. segmentreg (register) x86_registerNONE for now, but could be set
// if we have segment overrides
MCOperand baseReg;
MCOperand scaleAmount;
MCOperand indexReg;
MCOperand displacement;
MCOperand segmentReg;
uint64_t pcrel = 0;
if (insn.eaBase == EA_BASE_sib || insn.eaBase == EA_BASE_sib64) {
if (insn.sibBase != SIB_BASE_NONE) {
switch (insn.sibBase) {
default:
debug("Unexpected sibBase");
return true;
#define ENTRY(x) \
case SIB_BASE_##x: \
baseReg = MCOperand::createReg(X86::x); break;
ALL_SIB_BASES
#undef ENTRY
}
} else {
baseReg = MCOperand::createReg(X86::NoRegister);
}
if (insn.sibIndex != SIB_INDEX_NONE) {
switch (insn.sibIndex) {
default:
debug("Unexpected sibIndex");
return true;
#define ENTRY(x) \
case SIB_INDEX_##x: \
indexReg = MCOperand::createReg(X86::x); break;
EA_BASES_32BIT
EA_BASES_64BIT
REGS_XMM
REGS_YMM
REGS_ZMM
#undef ENTRY
}
} else {
// Use EIZ/RIZ for a few ambiguous cases where the SIB byte is present,
// but no index is used and modrm alone should have been enough.
// -No base register in 32-bit mode. In 64-bit mode this is used to
// avoid rip-relative addressing.
// -Any base register used other than ESP/RSP/R12D/R12. Using these as a
// base always requires a SIB byte.
// -A scale other than 1 is used.
if (insn.sibScale != 1 ||
(insn.sibBase == SIB_BASE_NONE && insn.mode != MODE_64BIT) ||
(insn.sibBase != SIB_BASE_NONE &&
insn.sibBase != SIB_BASE_ESP && insn.sibBase != SIB_BASE_RSP &&
insn.sibBase != SIB_BASE_R12D && insn.sibBase != SIB_BASE_R12)) {
indexReg = MCOperand::createReg(insn.addressSize == 4 ? X86::EIZ :
X86::RIZ);
} else
indexReg = MCOperand::createReg(X86::NoRegister);
}
scaleAmount = MCOperand::createImm(insn.sibScale);
} else {
switch (insn.eaBase) {
case EA_BASE_NONE:
if (insn.eaDisplacement == EA_DISP_NONE) {
debug("EA_BASE_NONE and EA_DISP_NONE for ModR/M base");
return true;
}
if (insn.mode == MODE_64BIT){
pcrel = insn.startLocation +
insn.displacementOffset + insn.displacementSize;
tryAddingPcLoadReferenceComment(insn.startLocation +
insn.displacementOffset,
insn.displacement + pcrel, Dis);
// Section 2.2.1.6
baseReg = MCOperand::createReg(insn.addressSize == 4 ? X86::EIP :
X86::RIP);
}
else
baseReg = MCOperand::createReg(X86::NoRegister);
indexReg = MCOperand::createReg(X86::NoRegister);
break;
case EA_BASE_BX_SI:
baseReg = MCOperand::createReg(X86::BX);
indexReg = MCOperand::createReg(X86::SI);
break;
case EA_BASE_BX_DI:
baseReg = MCOperand::createReg(X86::BX);
indexReg = MCOperand::createReg(X86::DI);
break;
case EA_BASE_BP_SI:
baseReg = MCOperand::createReg(X86::BP);
indexReg = MCOperand::createReg(X86::SI);
break;
case EA_BASE_BP_DI:
baseReg = MCOperand::createReg(X86::BP);
indexReg = MCOperand::createReg(X86::DI);
break;
default:
indexReg = MCOperand::createReg(X86::NoRegister);
switch (insn.eaBase) {
default:
debug("Unexpected eaBase");
return true;
// Here, we will use the fill-ins defined above. However,
// BX_SI, BX_DI, BP_SI, and BP_DI are all handled above and
// sib and sib64 were handled in the top-level if, so they're only
// placeholders to keep the compiler happy.
#define ENTRY(x) \
case EA_BASE_##x: \
baseReg = MCOperand::createReg(X86::x); break;
ALL_EA_BASES
#undef ENTRY
#define ENTRY(x) case EA_REG_##x:
ALL_REGS
#undef ENTRY
debug("A R/M memory operand may not be a register; "
"the base field must be a base.");
return true;
}
}
scaleAmount = MCOperand::createImm(1);
}
displacement = MCOperand::createImm(insn.displacement);
segmentReg = MCOperand::createReg(segmentRegnums[insn.segmentOverride]);
mcInst.addOperand(baseReg);
mcInst.addOperand(scaleAmount);
mcInst.addOperand(indexReg);
if(!tryAddingSymbolicOperand(insn.displacement + pcrel, false,
insn.startLocation, insn.displacementOffset,
insn.displacementSize, mcInst, Dis))
mcInst.addOperand(displacement);
mcInst.addOperand(segmentReg);
return false;
}
/// translateRM - Translates an operand stored in the R/M (and possibly SIB)
/// byte of an instruction to LLVM form, and appends it to an MCInst.
///
/// @param mcInst - The MCInst to append to.
/// @param operand - The operand, as stored in the descriptor table.
/// @param insn - The instruction to extract Mod, R/M, and SIB fields
/// from.
/// @return - 0 on success; nonzero otherwise
static bool translateRM(MCInst &mcInst, const OperandSpecifier &operand,
InternalInstruction &insn, const MCDisassembler *Dis) {
switch (operand.type) {
default:
debug("Unexpected type for a R/M operand");
return true;
case TYPE_R8:
case TYPE_R16:
case TYPE_R32:
case TYPE_R64:
case TYPE_Rv:
case TYPE_MM64:
case TYPE_XMM:
case TYPE_YMM:
case TYPE_ZMM:
case TYPE_VK:
case TYPE_DEBUGREG:
case TYPE_CONTROLREG:
case TYPE_BNDR:
return translateRMRegister(mcInst, insn);
case TYPE_M:
case TYPE_MVSIBX:
case TYPE_MVSIBY:
case TYPE_MVSIBZ:
return translateRMMemory(mcInst, insn, Dis);
}
}
/// translateFPRegister - Translates a stack position on the FPU stack to its
/// LLVM form, and appends it to an MCInst.
///
/// @param mcInst - The MCInst to append to.
/// @param stackPos - The stack position to translate.
static void translateFPRegister(MCInst &mcInst,
uint8_t stackPos) {
mcInst.addOperand(MCOperand::createReg(X86::ST0 + stackPos));
}
/// translateMaskRegister - Translates a 3-bit mask register number to
/// LLVM form, and appends it to an MCInst.
///
/// @param mcInst - The MCInst to append to.
/// @param maskRegNum - Number of mask register from 0 to 7.
/// @return - false on success; true otherwise.
static bool translateMaskRegister(MCInst &mcInst,
uint8_t maskRegNum) {
if (maskRegNum >= 8) {
debug("Invalid mask register number");
return true;
}
mcInst.addOperand(MCOperand::createReg(X86::K0 + maskRegNum));
return false;
}
/// translateOperand - Translates an operand stored in an internal instruction
/// to LLVM's format and appends it to an MCInst.
///
/// @param mcInst - The MCInst to append to.
/// @param operand - The operand, as stored in the descriptor table.
/// @param insn - The internal instruction.
/// @return - false on success; true otherwise.
static bool translateOperand(MCInst &mcInst, const OperandSpecifier &operand,
InternalInstruction &insn,
const MCDisassembler *Dis) {
switch (operand.encoding) {
default:
debug("Unhandled operand encoding during translation");
return true;
case ENCODING_REG:
translateRegister(mcInst, insn.reg);
return false;
case ENCODING_WRITEMASK:
return translateMaskRegister(mcInst, insn.writemask);
CASE_ENCODING_RM:
CASE_ENCODING_VSIB:
return translateRM(mcInst, operand, insn, Dis);
case ENCODING_IB:
case ENCODING_IW:
case ENCODING_ID:
case ENCODING_IO:
case ENCODING_Iv:
case ENCODING_Ia:
translateImmediate(mcInst,
insn.immediates[insn.numImmediatesTranslated++],
operand,
insn,
Dis);
return false;
case ENCODING_IRC:
mcInst.addOperand(MCOperand::createImm(insn.RC));
return false;
case ENCODING_SI:
return translateSrcIndex(mcInst, insn);
case ENCODING_DI:
return translateDstIndex(mcInst, insn);
case ENCODING_RB:
case ENCODING_RW:
case ENCODING_RD:
case ENCODING_RO:
case ENCODING_Rv:
translateRegister(mcInst, insn.opcodeRegister);
return false;
case ENCODING_CC:
mcInst.addOperand(MCOperand::createImm(insn.immediates[1]));
return false;
case ENCODING_FP:
translateFPRegister(mcInst, insn.modRM & 7);
return false;
case ENCODING_VVVV:
translateRegister(mcInst, insn.vvvv);
return false;
case ENCODING_DUP:
return translateOperand(mcInst, insn.operands[operand.type - TYPE_DUP0],
insn, Dis);
}
}
/// translateInstruction - Translates an internal instruction and all its
/// operands to an MCInst.
///
/// @param mcInst - The MCInst to populate with the instruction's data.
/// @param insn - The internal instruction.
/// @return - false on success; true otherwise.
static bool translateInstruction(MCInst &mcInst,
InternalInstruction &insn,
const MCDisassembler *Dis) {
if (!insn.spec) {
debug("Instruction has no specification");
return true;
}
mcInst.clear();
mcInst.setOpcode(insn.instructionID);
// If when reading the prefix bytes we determined the overlapping 0xf2 or 0xf3
// prefix bytes should be disassembled as xrelease and xacquire then set the
// opcode to those instead of the rep and repne opcodes.
if (insn.xAcquireRelease) {
if(mcInst.getOpcode() == X86::REP_PREFIX)
mcInst.setOpcode(X86::XRELEASE_PREFIX);
else if(mcInst.getOpcode() == X86::REPNE_PREFIX)
mcInst.setOpcode(X86::XACQUIRE_PREFIX);
}
insn.numImmediatesTranslated = 0;
for (const auto &Op : insn.operands) {
if (Op.encoding != ENCODING_NONE) {
if (translateOperand(mcInst, Op, insn, Dis)) {
return true;
}
}
}
return false;
}
static MCDisassembler *createX86Disassembler(const Target &T,
const MCSubtargetInfo &STI,
MCContext &Ctx) {
std::unique_ptr<const MCInstrInfo> MII(T.createMCInstrInfo());
return new X86GenericDisassembler(STI, Ctx, std::move(MII));
}
extern "C" void LLVMInitializeX86Disassembler() {
// Register the disassembler.
TargetRegistry::RegisterMCDisassembler(getTheX86_32Target(),
createX86Disassembler);
TargetRegistry::RegisterMCDisassembler(getTheX86_64Target(),
createX86Disassembler);
}
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