bool
instr_is_mov_constant(instr_t *instr, ptr_int_t *value)
{
int opc = instr_get_opcode(instr);
if (opc == OP_eor) {
/* We include OP_eor for symmetry w/ x86, but on ARM "mov reg, #0" is
* just as compact and there's no reason to use an xor.
*/
if (opnd_same(instr_get_src(instr, 0), instr_get_dst(instr, 0)) &&
opnd_same(instr_get_src(instr, 0), instr_get_src(instr, 1)) &&
/* Must be the form with "sh2, i5_7" and no shift */
instr_num_srcs(instr) == 4 &&
opnd_get_immed_int(instr_get_src(instr, 2)) == DR_SHIFT_NONE &&
opnd_get_immed_int(instr_get_src(instr, 3)) == 0) {
*value = 0;
return true;
} else
return false;
} else if (opc == OP_mvn || opc == OP_mvns) {
opnd_t op = instr_get_src(instr, 0);
if (opnd_is_immed_int(op)) {
*value = -opnd_get_immed_int(op);
return true;
} else
return false;
} else if (opc == OP_mov || opc == OP_movs || opc == OP_movw) {
opnd_t op = instr_get_src(instr, 0);
if (opnd_is_immed_int(op)) {
*value = opnd_get_immed_int(op);
return true;
} else
return false;
}
return false;
}
static bool
instr_is_reg_restore(instr_t *instr, reg_id_t reg, umbra_info_t *info)
{
opnd_t opnd;
int slot;
if (instr_get_opcode(instr) != OP_mov_ld)
return false;
opnd = instr_get_dst(instr, 0);
if (!opnd_is_reg(opnd) || opnd_get_reg(opnd) != reg)
return false;
slot = reg - REG_SPILL_START;
opnd = OPND_CREATE_ABSMEM(&info->spill_regs[slot], OPSZ_PTR);
if (opnd_same(opnd, instr_get_src(instr, 0)))
return true;
return false;
}
static bool
reg_update_is_limited(instr_t *instr, reg_id_t reg)
{
int opcode;
int offset;
opcode = instr_get_opcode(instr);
if (opcode == OP_inc || opcode == OP_dec)
return true;
if (opcode == OP_and)
/* for 0xffffffd0 & reg => reg */
return true;
if ((opcode == OP_add || opcode == OP_sub ||
opcode == OP_adc || opcode == OP_sbb) &&
opnd_is_immed_int(instr_get_src(instr, 0))) {
offset = opnd_get_immed_int(instr_get_src(instr, 0));
if (offset > PAGE_SIZE || offset < -PAGE_SIZE)
return false;
return true;
}
if (reg != DR_REG_XSP)
return false;
if (opcode >= OP_push && opcode <= OP_popa) {
if (opcode == OP_pop && opnd_same(instr_get_dst(instr, 0),
opnd_create_reg(DR_REG_XSP)))
return false;
return true;
}
if (opcode >= OP_call && opcode <= OP_call_far_ind)
return true;
if (opcode == OP_ret || opcode == OP_ret_far ||
opcode == OP_enter || opcode == OP_leave ||
opcode == OP_pushf || opcode == OP_popf)
return true;
return false;
}