bool
EmulateInstructionMIPS::Emulate_LW (llvm::MCInst& insn)
{
uint32_t src, base;
src = m_reg_info->getEncodingValue (insn.getOperand(0).getReg());
base = m_reg_info->getEncodingValue (insn.getOperand(1).getReg());
if (base == gcc_dwarf_sp_mips64 && nonvolatile_reg_p (src))
{
RegisterValue data_src;
RegisterInfo reg_info_src;
if (!GetRegisterInfo (eRegisterKindDWARF, gcc_dwarf_zero_mips64 + src, reg_info_src))
return false;
Context context;
context.type = eContextRegisterLoad;
if (!WriteRegister (context, ®_info_src, data_src))
return false;
return true;
}
return false;
}
bool
EmulateInstructionMIPS::Emulate_ADDiu (llvm::MCInst& insn)
{
bool success = false;
const uint32_t imm16 = insn.getOperand(2).getImm();
uint32_t imm = SignedBits(imm16, 15, 0);
uint64_t result;
uint32_t src, dst;
dst = m_reg_info->getEncodingValue (insn.getOperand(0).getReg());
src = m_reg_info->getEncodingValue (insn.getOperand(1).getReg());
/* Check if this is addiu sp,<src>,imm16 */
if (dst == gcc_dwarf_sp_mips64)
{
/* read <src> register */
uint64_t src_opd_val = ReadRegisterUnsigned (eRegisterKindDWARF, gcc_dwarf_zero_mips64 + src, 0, &success);
if (!success)
return false;
result = src_opd_val + imm;
Context context;
RegisterInfo reg_info_sp;
if (GetRegisterInfo (eRegisterKindDWARF, gcc_dwarf_sp_mips64, reg_info_sp))
context.SetRegisterPlusOffset (reg_info_sp, imm);
/* We are allocating bytes on stack */
context.type = eContextAdjustStackPointer;
WriteRegisterUnsigned (context, eRegisterKindDWARF, gcc_dwarf_sp_mips64, result);
}
return true;
}
static std::string getLocalName(const llvm::MCInst& inst, unsigned iop) {
const llvm::MCOperand& op = inst.getOperand(iop);
if (op.isReg() && strcmp(MRI->getName(op.getReg()), "RBP") == 0) {
char buf[128];
snprintf(buf, 128, "local_%x", -inst.getOperand(iop + 3).getImm());
return std::string(buf);
} else {
return std::string("UNK");
}
}
bool
EmulateInstructionMIPS::Emulate_SW (llvm::MCInst& insn)
{
bool success = false;
uint32_t imm16 = insn.getOperand(2).getImm();
uint32_t imm = SignedBits(imm16, 15, 0);
uint32_t src, base;
src = m_reg_info->getEncodingValue (insn.getOperand(0).getReg());
base = m_reg_info->getEncodingValue (insn.getOperand(1).getReg());
/* We look for sp based non-volatile register stores */
if (base == gcc_dwarf_sp_mips64 && nonvolatile_reg_p (src))
{
uint32_t address;
RegisterInfo reg_info_base;
RegisterInfo reg_info_src;
if (!GetRegisterInfo (eRegisterKindDWARF, gcc_dwarf_zero_mips64 + base, reg_info_base)
|| !GetRegisterInfo (eRegisterKindDWARF, gcc_dwarf_zero_mips64 + src, reg_info_src))
return false;
/* read SP */
address = ReadRegisterUnsigned (eRegisterKindDWARF, gcc_dwarf_zero_mips64 + base, 0, &success);
if (!success)
return false;
/* destination address */
address = address + imm;
Context context;
RegisterValue data_src;
context.type = eContextPushRegisterOnStack;
context.SetRegisterToRegisterPlusOffset (reg_info_src, reg_info_base, 0);
uint8_t buffer [RegisterValue::kMaxRegisterByteSize];
Error error;
if (!ReadRegister (®_info_base, data_src))
return false;
if (data_src.GetAsMemoryData (®_info_src, buffer, reg_info_src.byte_size, eByteOrderLittle, error) == 0)
return false;
if (!WriteMemory (context, address, buffer, reg_info_src.byte_size))
return false;
return true;
}
return false;
}
static void printInst(const llvm::MCInst& inst) {
const llvm::MCInstrDesc& id = MII->get(inst.getOpcode());
llvm::outs() << MII->getName(inst.getOpcode()) << " (" << inst.getNumOperands() << ") ";
for (int iop = 0; iop < inst.getNumOperands(); ++iop) {
const llvm::MCOperand& op = inst.getOperand(iop);
if (op.isReg()) {
unsigned reg = op.getReg();
const char* rcName;
char clsn[128];
if (id.OpInfo[iop].RegClass < MRI->getNumRegClasses()) {
const llvm::MCRegisterClass& rc = MRI->getRegClass(id.OpInfo[iop].RegClass);
rcName = rc.getName();
} else {
snprintf(clsn, sizeof(clsn), "CLS%d", id.OpInfo[iop].RegClass);
rcName = clsn;
}
llvm::outs() << MRI->getName(reg) << "(" << rcName << ", " << (uint64_t)id.OpInfo[iop].OperandType << ")";
} else if (op.isImm()) {
llvm::outs() << op.getImm() << "(" << (uint64_t)id.OpInfo[iop].OperandType << ")";
} else {
llvm::outs() << "<UNK>";
}
llvm::outs() << ", ";
}
llvm::outs() << "\n";
}
// Convert the given assembly instruction into an inline ASM operation in lieu
// of decompiling it. The output instruction will look something like this
// (although note that i128 doesn't work properly with LLVM codegen for the
// inline ASM instructions, necessitating a vector instead).
// %151 = load i128, i128* %XMM0_read
// %152 = bitcast i128 %151 to <16 x i8>
// %153 = load i128, i128* %XMM1_read
// %154 = bitcast i128 %153 to <16 x i8>
// %AESDECrr = call <16 x i8> asm "\09aesdec\09%xmm1, %xmm0", "={XMM0},{XMM0},{XMM1}"(<16 x i8> %152, <16 x i8> %154)
// %155 = bitcast <16 x i8> %AESDECrr to i128
// store volatile i128 %155, i128* %XMM0_write
void ArchBuildInlineAsm(llvm::MCInst &inst, llvm::BasicBlock *block) {
auto opcode = inst.getOpcode();
// Use the printer to build the ASM string. We'll need to escape the $ in
// register names with $$.
std::stringstream asmString;
{
std::string outS;
llvm::raw_string_ostream strOut(outS);
gIP->printInst(&inst, strOut, "", *gSTI);
for (char c : strOut.str()) {
if (c == '$')
asmString << "$$";
else
asmString << c;
}
}
// Next, find all the registers being used as definitions or uses in the
// inline ASM. This will write up the constraints for us, as well as
// provide us with a list of types (for the inline ASM output) and a list of
// values to pass into the string.
llvm::SmallVector<llvm::Value *, 3> operands;
llvm::SmallVector<llvm::Type *, 3> resultTypes;
std::stringstream constraints;
for (unsigned i = 0; i < inst.getNumOperands(); i++) {
llvm::MCOperand &op = inst.getOperand(i);
if (op.isReg()) {
unsigned regSize = ArchRegisterSize(op.getReg());
if (constraints.tellp() > 0) constraints << ",";
if (i < gMII->get(opcode).getNumDefs()) {
constraints << "=";
if (regSize > 64) {
// LLVM can't handle register constraints of i128, so we
// need to map this to <16 x i8>.
resultTypes.push_back(llvm::VectorType::get(
llvm::Type::getInt8Ty(block->getContext()), regSize / 8));
} else {
resultTypes.push_back(llvm::IntegerType::get(block->getContext(),
regSize));
}
} else {
auto readReg = GENERIC_MC_READREG(block, op.getReg(), regSize);
if (regSize > 64) {
// LLVM can't handle register constraints of i128, so we
// need to map this to <16 x i8>.
readReg = llvm::CastInst::Create(llvm::Instruction::BitCast, readReg,
llvm::VectorType::get(llvm::Type::getInt8Ty(block->getContext()), regSize / 8),
"", block);
}
operands.push_back(readReg);
}
constraints << "{" << gMRI->getName(op.getReg()) << "}";
}
}
// With all of these pieces, piece together the actual call to the inline ASM
// string.
llvm::SmallVector<llvm::Type *, 3> argTypes;
for (auto val : operands)
argTypes.push_back(val->getType());
llvm::Type *returnTy;
if (resultTypes.empty())
returnTy = llvm::Type::getVoidTy(block->getContext());
else if (resultTypes.size() == 1)
returnTy = resultTypes[0];
else
returnTy = llvm::StructType::get(block->getContext(), resultTypes);
auto asmTy = llvm::FunctionType::get(returnTy, argTypes, false);
auto callee = llvm::InlineAsm::get(asmTy, asmString.str(), constraints.str(),
false);
llvm::Value *resultPack =
llvm::CallInst::Create(callee, operands, "", block);
// Unpack the called registers into the LLVM values.
for (unsigned i = 0; i < resultTypes.size(); i++) {
llvm::Value *result = resultTypes.size() == 1 ? resultPack :
llvm::ExtractValueInst::Create(resultPack, i, "", block);
llvm::Type *ty = resultTypes[i];
// Cast vector outputs to iXYZ for R_WRITE.
if (ty->isVectorTy()) {
ty = llvm::Type::getIntNTy(block->getContext(),
ty->getVectorNumElements() * 8);
result = llvm::CastInst::Create(llvm::Instruction::BitCast, result,
ty, "", block);
}
unsigned regNo = inst.getOperand(i).getReg();
GENERIC_MC_WRITEREG(block, regNo, result);
}
}
