llvm-6502/lib/Target/X86/Disassembler/X86Disassembler.cpp
Sean Callanan a144c3f34d Fixes to the X86 disassembler. The disassembler will now
return an error status in all failure cases, printing
messages to debugs() only when debugging is enabled.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100229 91177308-0d34-0410-b5e6-96231b3b80d8
2010-04-02 21:23:51 +00:00

510 lines
16 KiB
C++

//===- X86Disassembler.cpp - Disassembler for x86 and x86_64 ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is part of the X86 Disassembler.
// It contains code to translate the data produced by the decoder into
// MCInsts.
// Documentation for the disassembler can be found in X86Disassembler.h.
//
//===----------------------------------------------------------------------===//
#include "X86Disassembler.h"
#include "X86DisassemblerDecoder.h"
#include "llvm/MC/MCDisassembler.h"
#include "llvm/MC/MCDisassembler.h"
#include "llvm/MC/MCInst.h"
#include "llvm/Target/TargetRegistry.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MemoryObject.h"
#include "llvm/Support/raw_ostream.h"
#include "X86GenRegisterNames.inc"
using namespace llvm;
using namespace llvm::X86Disassembler;
void x86DisassemblerDebug(const char *file,
unsigned line,
const char *s) {
dbgs() << file << ":" << line << ": " << s;
}
#define debug(s) DEBUG(x86DisassemblerDebug(__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
};
}
extern Target TheX86_32Target, TheX86_64Target;
}
static bool translateInstruction(MCInst &target,
InternalInstruction &source);
X86GenericDisassembler::X86GenericDisassembler(DisassemblerMode mode) :
MCDisassembler(),
fMode(mode) {
}
X86GenericDisassembler::~X86GenericDisassembler() {
}
/// regionReader - a callback function that wraps the readByte method from
/// MemoryObject.
///
/// @param arg - The generic callback parameter. In this case, this should
/// be a pointer to a MemoryObject.
/// @param byte - A pointer to the byte to be read.
/// @param address - The address to be read.
static int regionReader(void* arg, uint8_t* byte, uint64_t address) {
MemoryObject* region = static_cast<MemoryObject*>(arg);
return region->readByte(address, byte);
}
/// 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
//
bool X86GenericDisassembler::getInstruction(MCInst &instr,
uint64_t &size,
const MemoryObject &region,
uint64_t address,
raw_ostream &vStream) const {
InternalInstruction internalInstr;
int ret = decodeInstruction(&internalInstr,
regionReader,
(void*)&region,
logger,
(void*)&vStream,
address,
fMode);
if (ret) {
size = internalInstr.readerCursor - address;
return false;
}
else {
size = internalInstr.length;
return !translateInstruction(instr, internalInstr);
}
}
//
// 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,
uint8_t llvmRegnums[] = {
ALL_REGS
0
};
#undef ENTRY
uint8_t llvmRegnum = llvmRegnums[reg];
mcInst.addOperand(MCOperand::CreateReg(llvmRegnum));
}
/// translateImmediate - Appends an immediate operand to an MCInst.
///
/// @param mcInst - The MCInst to append to.
/// @param immediate - The immediate value to append.
static void translateImmediate(MCInst &mcInst, uint64_t immediate) {
mcInst.addOperand(MCOperand::CreateImm(immediate));
}
/// 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.
/// @param sr - Whether or not to emit the segment register. The
/// LEA instruction does not expect a segment-register
/// operand.
/// @return - 0 on success; nonzero otherwise
static bool translateRMMemory(MCInst &mcInst,
InternalInstruction &insn,
bool sr) {
// 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;
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(0);
}
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
#undef ENTRY
}
} else {
indexReg = MCOperand::CreateReg(0);
}
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)
baseReg = MCOperand::CreateReg(X86::RIP); // Section 2.2.1.6
else
baseReg = MCOperand::CreateReg(0);
indexReg = MCOperand::CreateReg(0);
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(0);
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);
static const uint8_t segmentRegnums[SEG_OVERRIDE_max] = {
0, // SEG_OVERRIDE_NONE
X86::CS,
X86::SS,
X86::DS,
X86::ES,
X86::FS,
X86::GS
};
segmentReg = MCOperand::CreateReg(segmentRegnums[insn.segmentOverride]);
mcInst.addOperand(baseReg);
mcInst.addOperand(scaleAmount);
mcInst.addOperand(indexReg);
mcInst.addOperand(displacement);
if (sr)
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,
OperandSpecifier &operand,
InternalInstruction &insn) {
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_MM:
case TYPE_MM32:
case TYPE_MM64:
case TYPE_XMM:
case TYPE_XMM32:
case TYPE_XMM64:
case TYPE_XMM128:
case TYPE_DEBUGREG:
case TYPE_CR32:
case TYPE_CR64:
return translateRMRegister(mcInst, insn);
case TYPE_M:
case TYPE_M8:
case TYPE_M16:
case TYPE_M32:
case TYPE_M64:
case TYPE_M128:
case TYPE_M512:
case TYPE_Mv:
case TYPE_M32FP:
case TYPE_M64FP:
case TYPE_M80FP:
case TYPE_M16INT:
case TYPE_M32INT:
case TYPE_M64INT:
case TYPE_M1616:
case TYPE_M1632:
case TYPE_M1664:
return translateRMMemory(mcInst, insn, true);
case TYPE_LEA:
return translateRMMemory(mcInst, insn, false);
}
}
/// 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.
/// @return - 0 on success; nonzero otherwise.
static bool translateFPRegister(MCInst &mcInst,
uint8_t stackPos) {
if (stackPos >= 8) {
debug("Invalid FP stack position");
return true;
}
mcInst.addOperand(MCOperand::CreateReg(X86::ST0 + stackPos));
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,
OperandSpecifier &operand,
InternalInstruction &insn) {
switch (operand.encoding) {
default:
debug("Unhandled operand encoding during translation");
return true;
case ENCODING_REG:
translateRegister(mcInst, insn.reg);
return false;
case ENCODING_RM:
return translateRM(mcInst, operand, insn);
case ENCODING_CB:
case ENCODING_CW:
case ENCODING_CD:
case ENCODING_CP:
case ENCODING_CO:
case ENCODING_CT:
debug("Translation of code offsets isn't supported.");
return true;
case ENCODING_IB:
case ENCODING_IW:
case ENCODING_ID:
case ENCODING_IO:
case ENCODING_Iv:
case ENCODING_Ia:
translateImmediate(mcInst,
insn.immediates[insn.numImmediatesTranslated++]);
return false;
case ENCODING_RB:
case ENCODING_RW:
case ENCODING_RD:
case ENCODING_RO:
translateRegister(mcInst, insn.opcodeRegister);
return false;
case ENCODING_I:
return translateFPRegister(mcInst, insn.opcodeModifier);
case ENCODING_Rv:
translateRegister(mcInst, insn.opcodeRegister);
return false;
case ENCODING_DUP:
return translateOperand(mcInst,
insn.spec->operands[operand.type - TYPE_DUP0],
insn);
}
}
/// 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) {
if (!insn.spec) {
debug("Instruction has no specification");
return true;
}
mcInst.setOpcode(insn.instructionID);
int index;
insn.numImmediatesTranslated = 0;
for (index = 0; index < X86_MAX_OPERANDS; ++index) {
if (insn.spec->operands[index].encoding != ENCODING_NONE) {
if (translateOperand(mcInst, insn.spec->operands[index], insn)) {
return true;
}
}
}
return false;
}
static MCDisassembler *createX86_32Disassembler(const Target &T) {
return new X86Disassembler::X86_32Disassembler;
}
static MCDisassembler *createX86_64Disassembler(const Target &T) {
return new X86Disassembler::X86_64Disassembler;
}
extern "C" void LLVMInitializeX86Disassembler() {
// Register the disassembler.
TargetRegistry::RegisterMCDisassembler(TheX86_32Target,
createX86_32Disassembler);
TargetRegistry::RegisterMCDisassembler(TheX86_64Target,
createX86_64Disassembler);
}