virtual size_t
Decode (const lldb_private::Disassembler &disassembler,
const lldb_private::DataExtractor &data,
lldb::offset_t data_offset)
{
// All we have to do is read the opcode which can be easy for some
// architectures
bool got_op = false;
DisassemblerLLVMC &llvm_disasm = GetDisassemblerLLVMC();
const ArchSpec &arch = llvm_disasm.GetArchitecture();
const lldb::ByteOrder byte_order = data.GetByteOrder();
const uint32_t min_op_byte_size = arch.GetMinimumOpcodeByteSize();
const uint32_t max_op_byte_size = arch.GetMaximumOpcodeByteSize();
if (min_op_byte_size == max_op_byte_size)
{
// Fixed size instructions, just read that amount of data.
if (!data.ValidOffsetForDataOfSize(data_offset, min_op_byte_size))
return false;
switch (min_op_byte_size)
{
case 1:
m_opcode.SetOpcode8 (data.GetU8 (&data_offset), byte_order);
got_op = true;
break;
case 2:
m_opcode.SetOpcode16 (data.GetU16 (&data_offset), byte_order);
got_op = true;
break;
case 4:
m_opcode.SetOpcode32 (data.GetU32 (&data_offset), byte_order);
got_op = true;
break;
case 8:
m_opcode.SetOpcode64 (data.GetU64 (&data_offset), byte_order);
got_op = true;
break;
default:
m_opcode.SetOpcodeBytes(data.PeekData(data_offset, min_op_byte_size), min_op_byte_size);
got_op = true;
break;
}
}
if (!got_op)
{
bool is_alternate_isa = false;
DisassemblerLLVMC::LLVMCDisassembler *mc_disasm_ptr = GetDisasmToUse (is_alternate_isa);
const llvm::Triple::ArchType machine = arch.GetMachine();
if (machine == llvm::Triple::arm || machine == llvm::Triple::thumb)
{
if (machine == llvm::Triple::thumb || is_alternate_isa)
{
uint32_t thumb_opcode = data.GetU16(&data_offset);
if ((thumb_opcode & 0xe000) != 0xe000 || ((thumb_opcode & 0x1800u) == 0))
{
m_opcode.SetOpcode16 (thumb_opcode, byte_order);
m_is_valid = true;
}
else
{
thumb_opcode <<= 16;
thumb_opcode |= data.GetU16(&data_offset);
m_opcode.SetOpcode16_2 (thumb_opcode, byte_order);
m_is_valid = true;
}
}
else
{
m_opcode.SetOpcode32 (data.GetU32(&data_offset), byte_order);
m_is_valid = true;
}
}
else
{
// The opcode isn't evenly sized, so we need to actually use the llvm
// disassembler to parse it and get the size.
uint8_t *opcode_data = const_cast<uint8_t *>(data.PeekData (data_offset, 1));
const size_t opcode_data_len = data.BytesLeft(data_offset);
const addr_t pc = m_address.GetFileAddress();
llvm::MCInst inst;
llvm_disasm.Lock(this, NULL);
const size_t inst_size = mc_disasm_ptr->GetMCInst(opcode_data,
opcode_data_len,
pc,
inst);
llvm_disasm.Unlock();
if (inst_size == 0)
m_opcode.Clear();
else
{
m_opcode.SetOpcodeBytes(opcode_data, inst_size);
m_is_valid = true;
}
}
}
return m_opcode.GetByteSize();
}
