diff options
Diffstat (limited to 'gdb/infrun.c')
| -rw-r--r-- | gdb/infrun.c | 117 |
1 files changed, 72 insertions, 45 deletions
diff --git a/gdb/infrun.c b/gdb/infrun.c index 1e3839a..5428a05 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -218,9 +218,30 @@ static struct cmd_list_element *stop_command; static struct symbol *step_start_function; -/* Nonzero if we are expecting a trace trap and should proceed from it. */ +/* Nonzero if we are presently stepping over a breakpoint. -static int trap_expected; + If we hit a breakpoint or watchpoint, and then continue, + we need to single step the current thread with breakpoints + disabled, to avoid hitting the same breakpoint or + watchpoint again. And we should step just a single + thread and keep other threads stopped, so that + other threads don't miss breakpoints while they are removed. + + So, this variable simultaneously means that we need to single + step the current thread, keep other threads stopped, and that + breakpoints should be removed while we step. + + This variable is set either: + - in proceed, when we resume inferior on user's explicit request + - in keep_going, if handle_inferior_event decides we need to + step over breakpoint. + + The variable is cleared in clear_proceed_status, called every + time before we call proceed. The proceed calls wait_for_inferior, + which calls handle_inferior_event in a loop, and until + wait_for_inferior exits, this variable is changed only by keep_going. */ + +static int stepping_over_breakpoint; /* Nonzero if we want to give control to the user when we're notified of shared library events by the dynamic linker. */ @@ -442,10 +463,14 @@ static CORE_ADDR singlestep_pc; static ptid_t saved_singlestep_ptid; static int stepping_past_singlestep_breakpoint; -/* Similarly, if we are stepping another thread past a breakpoint, - save the original thread here so that we can resume stepping it later. */ -static ptid_t stepping_past_breakpoint_ptid; -static int stepping_past_breakpoint; +/* If not equal to null_ptid, this means that after stepping over breakpoint + is finished, we need to switch to deferred_step_ptid, and step it. + + The use case is when one thread has hit a breakpoint, and then the user + has switched to another thread and issued 'step'. We need to step over + breakpoint in the thread which hit the breakpoint, but then continue + stepping the thread user has selected. */ +static ptid_t deferred_step_ptid; /* Things to clean up if we QUIT out of resume (). */ @@ -647,7 +672,7 @@ a command like `return' or `jump' to continue execution.")); void clear_proceed_status (void) { - trap_expected = 0; + stepping_over_breakpoint = 0; step_range_start = 0; step_range_end = 0; step_frame_id = null_frame_id; @@ -693,8 +718,7 @@ prepare_to_proceed (int step) /* If stepping, remember current thread to switch back to. */ if (step) { - stepping_past_breakpoint = 1; - stepping_past_breakpoint_ptid = inferior_ptid; + deferred_step_ptid = inferior_ptid; } /* Switch back to WAIT_PID thread. */ @@ -778,7 +802,7 @@ proceed (CORE_ADDR addr, enum target_signal siggnal, int step) if (oneproc) /* We will get a trace trap after one instruction. Continue it automatically and insert breakpoints then. */ - trap_expected = 1; + stepping_over_breakpoint = 1; else insert_breakpoints (); @@ -842,7 +866,7 @@ start_remote (int from_tty) init_thread_list (); init_wait_for_inferior (); stop_soon = STOP_QUIETLY_REMOTE; - trap_expected = 0; + stepping_over_breakpoint = 0; /* Always go on waiting for the target, regardless of the mode. */ /* FIXME: cagney/1999-09-23: At present it isn't possible to @@ -887,7 +911,7 @@ init_wait_for_inferior (void) clear_proceed_status (); stepping_past_singlestep_breakpoint = 0; - stepping_past_breakpoint = 0; + deferred_step_ptid = null_ptid; } /* This enum encodes possible reasons for doing a target_wait, so that @@ -924,7 +948,9 @@ struct execution_control_state { struct target_waitstatus ws; struct target_waitstatus *wp; - int another_trap; + /* Should we step over breakpoint next time keep_going + is called? */ + int stepping_over_breakpoint; int random_signal; CORE_ADDR stop_func_start; CORE_ADDR stop_func_end; @@ -1085,7 +1111,7 @@ fetch_inferior_event (void *client_data) void init_execution_control_state (struct execution_control_state *ecs) { - ecs->another_trap = 0; + ecs->stepping_over_breakpoint = 0; ecs->random_signal = 0; ecs->step_after_step_resume_breakpoint = 0; ecs->handling_longjmp = 0; /* FIXME */ @@ -1140,20 +1166,20 @@ context_switch (struct execution_control_state *ecs) { /* Perform infrun state context switch: */ /* Save infrun state for the old thread. */ save_infrun_state (inferior_ptid, prev_pc, - trap_expected, step_resume_breakpoint, + stepping_over_breakpoint, step_resume_breakpoint, step_range_start, step_range_end, &step_frame_id, - ecs->handling_longjmp, ecs->another_trap, + ecs->handling_longjmp, ecs->stepping_over_breakpoint, ecs->stepping_through_solib_after_catch, ecs->stepping_through_solib_catchpoints, ecs->current_line, ecs->current_symtab); /* Load infrun state for the new thread. */ load_infrun_state (ecs->ptid, &prev_pc, - &trap_expected, &step_resume_breakpoint, + &stepping_over_breakpoint, &step_resume_breakpoint, &step_range_start, &step_range_end, &step_frame_id, - &ecs->handling_longjmp, &ecs->another_trap, + &ecs->handling_longjmp, &ecs->stepping_over_breakpoint, &ecs->stepping_through_solib_after_catch, &ecs->stepping_through_solib_catchpoints, &ecs->current_line, &ecs->current_symtab); @@ -1610,17 +1636,15 @@ handle_inferior_event (struct execution_control_state *ecs) stepping_past_singlestep_breakpoint = 0; - if (stepping_past_breakpoint) + if (!ptid_equal (deferred_step_ptid, null_ptid)) { - stepping_past_breakpoint = 0; - /* If we stopped for some other reason than single-stepping, ignore the fact that we were supposed to switch back. */ if (stop_signal == TARGET_SIGNAL_TRAP) { if (debug_infrun) fprintf_unfiltered (gdb_stdlog, - "infrun: stepping_past_breakpoint\n"); + "infrun: handling deferred step\n"); /* Pull the single step breakpoints out of the target. */ if (singlestep_breakpoints_inserted_p) @@ -1631,7 +1655,8 @@ handle_inferior_event (struct execution_control_state *ecs) /* Note: We do not call context_switch at this point, as the context is already set up for stepping the original thread. */ - switch_to_thread (stepping_past_breakpoint_ptid); + switch_to_thread (deferred_step_ptid); + deferred_step_ptid = null_ptid; /* Suppress spurious "Switching to ..." message. */ previous_inferior_ptid = inferior_ptid; @@ -1639,6 +1664,8 @@ handle_inferior_event (struct execution_control_state *ecs) prepare_to_wait (ecs); return; } + + deferred_step_ptid = null_ptid; } /* See if a thread hit a thread-specific breakpoint that was meant for @@ -1769,7 +1796,7 @@ handle_inferior_event (struct execution_control_state *ecs) context_switch (ecs); ecs->waiton_ptid = ecs->ptid; ecs->wp = &(ecs->ws); - ecs->another_trap = 1; + ecs->stepping_over_breakpoint = 1; ecs->infwait_state = infwait_thread_hop_state; keep_going (ecs); @@ -1863,7 +1890,7 @@ handle_inferior_event (struct execution_control_state *ecs) &ecs->stop_func_start, &ecs->stop_func_end); ecs->stop_func_start += gdbarch_deprecated_function_start_offset (current_gdbarch); - ecs->another_trap = 0; + ecs->stepping_over_breakpoint = 0; bpstat_clear (&stop_bpstat); stop_step = 0; stop_stack_dummy = 0; @@ -1872,7 +1899,7 @@ handle_inferior_event (struct execution_control_state *ecs) stopped_by_random_signal = 0; if (stop_signal == TARGET_SIGNAL_TRAP - && trap_expected + && stepping_over_breakpoint && gdbarch_single_step_through_delay_p (current_gdbarch) && currently_stepping (ecs)) { @@ -1890,7 +1917,7 @@ handle_inferior_event (struct execution_control_state *ecs) { /* The user issued a continue when stopped at a breakpoint. Set up for another trap and get out of here. */ - ecs->another_trap = 1; + ecs->stepping_over_breakpoint = 1; keep_going (ecs); return; } @@ -1899,10 +1926,10 @@ handle_inferior_event (struct execution_control_state *ecs) /* The user issued a step when stopped at a breakpoint. Maybe we should stop, maybe we should not - the delay slot *might* correspond to a line of source. In any - case, don't decide that here, just set ecs->another_trap, - making sure we single-step again before breakpoints are - re-inserted. */ - ecs->another_trap = 1; + case, don't decide that here, just set + ecs->stepping_over_breakpoint, making sure we + single-step again before breakpoints are re-inserted. */ + ecs->stepping_over_breakpoint = 1; } } @@ -1910,7 +1937,7 @@ handle_inferior_event (struct execution_control_state *ecs) The alternatives are: 1) break; to really stop and return to the debugger, 2) drop through to start up again - (set ecs->another_trap to 1 to single step once) + (set ecs->stepping_over_breakpoint to 1 to single step once) 3) set ecs->random_signal to 1, and the decision between 1 and 2 will be made according to the signal handling tables. */ @@ -1994,7 +2021,7 @@ handle_inferior_event (struct execution_control_state *ecs) if (stop_signal == TARGET_SIGNAL_TRAP) ecs->random_signal = !(bpstat_explains_signal (stop_bpstat) - || trap_expected + || stepping_over_breakpoint || (step_range_end && step_resume_breakpoint == NULL)); else { @@ -2155,7 +2182,7 @@ process_event_stop_test: if (debug_infrun) fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_SINGLE\n"); remove_breakpoints (); - ecs->another_trap = 1; + ecs->stepping_over_breakpoint = 1; /* Still need to check other stuff, at least the case where we are stepping and step out of the right range. */ break; @@ -2216,7 +2243,7 @@ process_event_stop_test: to doing that. */ ecs->step_after_step_resume_breakpoint = 0; remove_breakpoints (); - ecs->another_trap = 1; + ecs->stepping_over_breakpoint = 1; keep_going (ecs); return; } @@ -2301,13 +2328,13 @@ process_event_stop_test: /* Be sure to lift all breakpoints, so the inferior does actually step past this point... */ - ecs->another_trap = 1; + ecs->stepping_over_breakpoint = 1; break; } else { /* We want to step over this breakpoint, then keep going. */ - ecs->another_trap = 1; + ecs->stepping_over_breakpoint = 1; break; } } @@ -2338,7 +2365,7 @@ process_event_stop_test: { if (debug_infrun) fprintf_unfiltered (gdb_stdlog, "infrun: stepping in dynamic linker\n"); - ecs->another_trap = 1; + ecs->stepping_over_breakpoint = 1; keep_going (ecs); return; } @@ -2734,7 +2761,7 @@ currently_stepping (struct execution_control_state *ecs) { return ((!ecs->handling_longjmp && ((step_range_end && step_resume_breakpoint == NULL) - || trap_expected)) + || stepping_over_breakpoint)) || ecs->stepping_through_solib_after_catch || bpstat_should_step ()); } @@ -2913,7 +2940,7 @@ keep_going (struct execution_control_state *ecs) /* If we did not do break;, it means we should keep running the inferior and not return to debugger. */ - if (trap_expected && stop_signal != TARGET_SIGNAL_TRAP) + if (stepping_over_breakpoint && stop_signal != TARGET_SIGNAL_TRAP) { /* We took a signal (which we are supposed to pass through to the inferior, else we'd have done a break above) and we @@ -2935,7 +2962,7 @@ keep_going (struct execution_control_state *ecs) already inserted breakpoints. Therefore, we don't care if breakpoints were already inserted, or not. */ - if (!ecs->another_trap) + if (!ecs->stepping_over_breakpoint) { struct gdb_exception e; /* Stop stepping when inserting breakpoints @@ -2951,7 +2978,7 @@ keep_going (struct execution_control_state *ecs) } } - trap_expected = ecs->another_trap; + stepping_over_breakpoint = ecs->stepping_over_breakpoint; /* Do not deliver SIGNAL_TRAP (except when the user explicitly specifies that such a signal should be delivered to the @@ -3669,7 +3696,7 @@ struct inferior_status int stop_step; int stop_stack_dummy; int stopped_by_random_signal; - int trap_expected; + int stepping_over_breakpoint; CORE_ADDR step_range_start; CORE_ADDR step_range_end; struct frame_id step_frame_id; @@ -3715,7 +3742,7 @@ save_inferior_status (int restore_stack_info) inf_status->stop_step = stop_step; inf_status->stop_stack_dummy = stop_stack_dummy; inf_status->stopped_by_random_signal = stopped_by_random_signal; - inf_status->trap_expected = trap_expected; + inf_status->stepping_over_breakpoint = stepping_over_breakpoint; inf_status->step_range_start = step_range_start; inf_status->step_range_end = step_range_end; inf_status->step_frame_id = step_frame_id; @@ -3767,7 +3794,7 @@ restore_inferior_status (struct inferior_status *inf_status) stop_step = inf_status->stop_step; stop_stack_dummy = inf_status->stop_stack_dummy; stopped_by_random_signal = inf_status->stopped_by_random_signal; - trap_expected = inf_status->trap_expected; + stepping_over_breakpoint = inf_status->stepping_over_breakpoint; step_range_start = inf_status->step_range_start; step_range_end = inf_status->step_range_end; step_frame_id = inf_status->step_frame_id; |