diff options
Diffstat (limited to 'lib/msandr/msandr.cc')
| -rw-r--r-- | lib/msandr/msandr.cc | 22 |
1 files changed, 8 insertions, 14 deletions
diff --git a/lib/msandr/msandr.cc b/lib/msandr/msandr.cc index ffea3e8a..c1faec2e 100644 --- a/lib/msandr/msandr.cc +++ b/lib/msandr/msandr.cc @@ -282,21 +282,14 @@ void InstrumentMops(void *drcontext, instrlist_t *bb, instr_t *instr, opnd_t op, } CHECK(reg_is_pointer_sized(R1)); // otherwise R2 may be wrong. - // Pick R2 that's not R1 or used by the operand. It's OK if the instr uses - // R2 elsewhere, since we'll restore it before instr. - reg_id_t GPR_TO_USE_FOR_R2[] = { - DR_REG_XAX, DR_REG_XBX, DR_REG_XCX, DR_REG_XDX - // Don't forget to update the +4 below if you add anything else! - }; - std::set<reg_id_t> unused_registers(GPR_TO_USE_FOR_R2, GPR_TO_USE_FOR_R2 + 4); - unused_registers.erase(R1); - for (int j = 0; j < opnd_num_regs_used(op); j++) { - unused_registers.erase(opnd_get_reg_used(op, j)); + // Pick R2 from R8 to R15. + // It's OK if the instr uses R2 elsewhere, since we'll restore it before instr. + reg_id_t R2; + for (R2 = DR_REG_R8; R2 <= DR_REG_R15; R2++) { + if (!opnd_uses_reg(op, R2)) + break; } - - CHECK(unused_registers.size() > 0); - reg_id_t R2 = *unused_registers.begin(); - CHECK(R1 != R2); + CHECK((R2 <= DR_REG_R15) && R1 != R2); // Save the current values of R1 and R2. dr_save_reg(drcontext, bb, instr, R1, SPILL_SLOT_1); @@ -334,6 +327,7 @@ void InstrumentMops(void *drcontext, instrlist_t *bb, instr_t *instr, opnd_t op, dr_restore_reg(drcontext, bb, instr, R1, SPILL_SLOT_1); dr_restore_reg(drcontext, bb, instr, R2, SPILL_SLOT_2); + // TODO: move aflags save/restore to per instr instead of per opnd if (need_to_restore_eflags) { if (VERBOSITY > 1) dr_printf("Restoring eflags\n"); |