diff options
Diffstat (limited to 'gdb/infrun.c')
| -rw-r--r-- | gdb/infrun.c | 95 |
1 files changed, 74 insertions, 21 deletions
diff --git a/gdb/infrun.c b/gdb/infrun.c index 0724546..da67e4b 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -1313,6 +1313,74 @@ handle_step_into_function (struct execution_control_state *ecs) return; } +static void +adjust_pc_after_break (struct execution_control_state *ecs) +{ + CORE_ADDR stop_pc; + + /* If this target does not decrement the PC after breakpoints, then + we have nothing to do. */ + if (DECR_PC_AFTER_BREAK == 0) + return; + + /* If we've hit a breakpoint, we'll normally be stopped with SIGTRAP. If + we aren't, just return. + + NOTE drow/2004-01-31: On some targets, breakpoints may generate + different signals (SIGILL or SIGEMT for instance), but it is less + clear where the PC is pointing afterwards. It may not match + DECR_PC_AFTER_BREAK. I don't know any specific target that generates + these signals at breakpoints (the code has been in GDB since at least + 1992) so I can not guess how to handle them here. + + In earlier versions of GDB, a target with HAVE_NONSTEPPABLE_WATCHPOINTS + would have the PC after hitting a watchpoint affected by + DECR_PC_AFTER_BREAK. I haven't found any target with both of these set + in GDB history, and it seems unlikely to be correct, so + HAVE_NONSTEPPABLE_WATCHPOINTS is not checked here. */ + + if (ecs->ws.kind != TARGET_WAITKIND_STOPPED) + return; + + if (ecs->ws.value.sig != TARGET_SIGNAL_TRAP) + return; + + /* Find the location where (if we've hit a breakpoint) the breakpoint would + be. */ + stop_pc = read_pc_pid (ecs->ptid) - DECR_PC_AFTER_BREAK; + + /* If we're software-single-stepping, then assume this is a breakpoint. + NOTE drow/2004-01-17: This doesn't check that the PC matches, or that + we're even in the right thread. The software-single-step code needs + some modernization. + + If we're not software-single-stepping, then we first check that there + is an enabled software breakpoint at this address. If there is, and + we weren't using hardware-single-step, then we've hit the breakpoint. + + If we were using hardware-single-step, we check prev_pc; if we just + stepped over an inserted software breakpoint, then we should decrement + the PC and eventually report hitting the breakpoint. The prev_pc check + prevents us from decrementing the PC if we just stepped over a jump + instruction and landed on the instruction after a breakpoint. + + The last bit checks that we didn't hit a breakpoint in a signal handler + without an intervening stop in sigtramp, which is detected by a new + stack pointer value below any usual function calling stack adjustments. + + NOTE drow/2004-01-17: I'm not sure that this is necessary. The check + predates checking for software single step at the same time. Also, + if we've moved into a signal handler we should have seen the + signal. */ + + if ((SOFTWARE_SINGLE_STEP_P () && singlestep_breakpoints_inserted_p) + || (software_breakpoint_inserted_here_p (stop_pc) + && !(currently_stepping (ecs) + && prev_pc != stop_pc + && !(step_range_end && INNER_THAN (read_sp (), (step_sp - 16)))))) + write_pc_pid (stop_pc, ecs->ptid); +} + /* Given an execution control state that has been freshly filled in by an event from the inferior, figure out what it means and take appropriate action. */ @@ -1332,6 +1400,8 @@ handle_inferior_event (struct execution_control_state *ecs) target_last_wait_ptid = ecs->ptid; target_last_waitstatus = *ecs->wp; + adjust_pc_after_break (ecs); + switch (ecs->infwait_state) { case infwait_thread_hop_state: @@ -1685,19 +1755,15 @@ handle_inferior_event (struct execution_control_state *ecs) /* Check if a regular breakpoint has been hit before checking for a potential single step breakpoint. Otherwise, GDB will not see this breakpoint hit when stepping onto breakpoints. */ - if (breakpoints_inserted - && breakpoint_here_p (stop_pc - DECR_PC_AFTER_BREAK)) + if (breakpoints_inserted && breakpoint_here_p (stop_pc)) { ecs->random_signal = 0; - if (!breakpoint_thread_match (stop_pc - DECR_PC_AFTER_BREAK, - ecs->ptid)) + if (!breakpoint_thread_match (stop_pc, ecs->ptid)) { int remove_status; /* Saw a breakpoint, but it was hit by the wrong thread. Just continue. */ - if (DECR_PC_AFTER_BREAK) - write_pc_pid (stop_pc - DECR_PC_AFTER_BREAK, ecs->ptid); remove_status = remove_breakpoints (); /* Did we fail to remove breakpoints? If so, try @@ -1710,7 +1776,7 @@ handle_inferior_event (struct execution_control_state *ecs) if (remove_status != 0) { /* FIXME! This is obviously non-portable! */ - write_pc_pid (stop_pc - DECR_PC_AFTER_BREAK + 4, ecs->ptid); + write_pc_pid (stop_pc + 4, ecs->ptid); /* We need to restart all the threads now, * unles we're running in scheduler-locked mode. * Use currently_stepping to determine whether to @@ -1744,17 +1810,6 @@ handle_inferior_event (struct execution_control_state *ecs) } else if (SOFTWARE_SINGLE_STEP_P () && singlestep_breakpoints_inserted_p) { - /* Readjust the stop_pc as it is off by DECR_PC_AFTER_BREAK - compared to the value it would have if the system stepping - capability was used. This allows the rest of the code in - this function to use this address without having to worry - whether software single step is in use or not. */ - if (DECR_PC_AFTER_BREAK) - { - stop_pc -= DECR_PC_AFTER_BREAK; - write_pc_pid (stop_pc, ecs->ptid); - } - sw_single_step_trap_p = 1; ecs->random_signal = 0; } @@ -1886,9 +1941,6 @@ handle_inferior_event (struct execution_control_state *ecs) includes evaluating watchpoints, things will come to a stop in the correct manner. */ - if (DECR_PC_AFTER_BREAK) - write_pc (stop_pc - DECR_PC_AFTER_BREAK); - remove_breakpoints (); registers_changed (); target_resume (ecs->ptid, 1, TARGET_SIGNAL_0); /* Single step */ @@ -3121,6 +3173,7 @@ normal_stop (void) previous_inferior_ptid = inferior_ptid; } + /* NOTE drow/2004-01-17: Is this still necessary? */ /* Make sure that the current_frame's pc is correct. This is a correction for setting up the frame info before doing DECR_PC_AFTER_BREAK */ |