diff options
Diffstat (limited to 'gdb/infrun.c')
| -rw-r--r-- | gdb/infrun.c | 1108 |
1 files changed, 1044 insertions, 64 deletions
diff --git a/gdb/infrun.c b/gdb/infrun.c index dc7ff3e..9690a36 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -61,6 +61,7 @@ #include "target-dcache.h" #include "terminal.h" #include "solist.h" +#include "event-loop.h" /* Prototypes for local functions */ @@ -101,6 +102,35 @@ static void insert_longjmp_resume_breakpoint (struct gdbarch *, CORE_ADDR); static int maybe_software_singlestep (struct gdbarch *gdbarch, CORE_ADDR pc); +/* Asynchronous signal handler registered as event loop source for + when we have pending events ready to be passed to the core. */ +static struct async_event_handler *infrun_async_inferior_event_token; + +/* Stores whether infrun_async was previously enabled or disabled. + Starts off as -1, indicating "never enabled/disabled". */ +static int infrun_is_async = -1; + +/* See infrun.h. */ + +void +infrun_async (int enable) +{ + if (infrun_is_async != enable) + { + infrun_is_async = enable; + + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: infrun_async(%d)\n", + enable); + + if (enable) + mark_async_event_handler (infrun_async_inferior_event_token); + else + clear_async_event_handler (infrun_async_inferior_event_token); + } +} + /* When set, stop the 'step' command if we enter a function which has no line number information. The normal behavior is that we step over such function. */ @@ -1303,6 +1333,9 @@ set_step_over_info (struct address_space *aspace, CORE_ADDR address, static void clear_step_over_info (void) { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: clear_step_over_info\n"); step_over_info.aspace = NULL; step_over_info.address = 0; step_over_info.nonsteppable_watchpoint_p = 0; @@ -1475,6 +1508,23 @@ get_displaced_stepping_state (int pid) return NULL; } +/* Returns true if any inferior has a thread doing a displaced + step. */ + +static int +displaced_step_in_progress_any_inferior (void) +{ + struct displaced_step_inferior_state *state; + + for (state = displaced_step_inferior_states; + state != NULL; + state = state->next) + if (!ptid_equal (state->step_ptid, null_ptid)) + return 1; + + return 0; +} + /* Return true if process PID has a thread doing a displaced step. */ static int @@ -1788,21 +1838,28 @@ displaced_step_restore (struct displaced_step_inferior_state *displaced, displaced->step_copy)); } -static void +/* If we displaced stepped an instruction successfully, adjust + registers and memory to yield the same effect the instruction would + have had if we had executed it at its original address, and return + 1. If the instruction didn't complete, relocate the PC and return + -1. If the thread wasn't displaced stepping, return 0. */ + +static int displaced_step_fixup (ptid_t event_ptid, enum gdb_signal signal) { struct cleanup *old_cleanups; struct displaced_step_inferior_state *displaced = get_displaced_stepping_state (ptid_get_pid (event_ptid)); + int ret; /* Was any thread of this process doing a displaced step? */ if (displaced == NULL) - return; + return 0; /* Was this event for the pid we displaced? */ if (ptid_equal (displaced->step_ptid, null_ptid) || ! ptid_equal (displaced->step_ptid, event_ptid)) - return; + return 0; old_cleanups = make_cleanup (displaced_step_clear_cleanup, displaced); @@ -1825,6 +1882,7 @@ displaced_step_fixup (ptid_t event_ptid, enum gdb_signal signal) displaced->step_original, displaced->step_copy, get_thread_regcache (displaced->step_ptid)); + ret = 1; } else { @@ -1835,11 +1893,14 @@ displaced_step_fixup (ptid_t event_ptid, enum gdb_signal signal) pc = displaced->step_original + (pc - displaced->step_copy); regcache_write_pc (regcache, pc); + ret = -1; } do_cleanups (old_cleanups); displaced->step_ptid = null_ptid; + + return ret; } /* Data to be passed around while handling an event. This data is @@ -1888,10 +1949,19 @@ start_step_over (void) { struct thread_info *tp, *next; + /* Don't start a new step-over if we already have an in-line + step-over operation ongoing. */ + if (step_over_info_valid_p ()) + return 0; + for (tp = step_over_queue_head; tp != NULL; tp = next) { struct execution_control_state ecss; struct execution_control_state *ecs = &ecss; + enum step_over_what step_what; + int must_be_in_line; + struct regcache *regcache = get_thread_regcache (tp->ptid); + struct gdbarch *gdbarch = get_regcache_arch (regcache); next = thread_step_over_chain_next (tp); @@ -1900,6 +1970,17 @@ start_step_over (void) if (displaced_step_in_progress (ptid_get_pid (tp->ptid))) continue; + step_what = thread_still_needs_step_over (tp); + must_be_in_line = ((step_what & STEP_OVER_WATCHPOINT) + || ((step_what & STEP_OVER_BREAKPOINT) + && !use_displaced_stepping (gdbarch))); + + /* We currently stop all threads of all processes to step-over + in-line. If we need to start a new in-line step-over, let + any pending displaced steps finish first. */ + if (must_be_in_line && displaced_step_in_progress_any_inferior ()) + return 0; + thread_step_over_chain_remove (tp); if (step_over_queue_head == NULL) @@ -1909,13 +1990,16 @@ start_step_over (void) "infrun: step-over queue now empty\n"); } - if (tp->control.trap_expected || tp->executing) + if (tp->control.trap_expected + || tp->resumed + || tp->executing) { internal_error (__FILE__, __LINE__, "[%s] has inconsistent state: " - "trap_expected=%d, executing=%d\n", + "trap_expected=%d, resumed=%d, executing=%d\n", target_pid_to_str (tp->ptid), tp->control.trap_expected, + tp->resumed, tp->executing); } @@ -1930,7 +2014,7 @@ start_step_over (void) because we wouldn't be able to resume anything else until the target stops again. In non-stop, the resume always resumes only TP, so it's OK to let the thread resume freely. */ - if (!non_stop && !thread_still_needs_step_over (tp)) + if (!non_stop && !step_what) continue; switch_to_thread (tp->ptid); @@ -1940,6 +2024,15 @@ start_step_over (void) if (!ecs->wait_some_more) error (_("Command aborted.")); + gdb_assert (tp->resumed); + + /* If we started a new in-line step-over, we're done. */ + if (step_over_info_valid_p ()) + { + gdb_assert (tp->control.trap_expected); + return 1; + } + if (!non_stop) { /* On all-stop, shouldn't have resumed unless we needed a @@ -2155,12 +2248,46 @@ resume (enum gdb_signal sig) single-step). */ int step; - tp->stepped_breakpoint = 0; - gdb_assert (!thread_is_in_step_over_chain (tp)); QUIT; + if (tp->suspend.waitstatus_pending_p) + { + if (debug_infrun) + { + char *statstr; + + statstr = target_waitstatus_to_string (&tp->suspend.waitstatus); + fprintf_unfiltered (gdb_stdlog, + "infrun: resume: thread %s has pending wait status %s " + "(currently_stepping=%d).\n", + target_pid_to_str (tp->ptid), statstr, + currently_stepping (tp)); + xfree (statstr); + } + + tp->resumed = 1; + + /* FIXME: What should we do if we are supposed to resume this + thread with a signal? Maybe we should maintain a queue of + pending signals to deliver. */ + if (sig != GDB_SIGNAL_0) + { + warning (_("Couldn't deliver signal %s to %s.\n"), + gdb_signal_to_name (sig), target_pid_to_str (tp->ptid)); + } + + tp->suspend.stop_signal = GDB_SIGNAL_0; + discard_cleanups (old_cleanups); + + if (target_can_async_p ()) + target_async (1); + return; + } + + tp->stepped_breakpoint = 0; + /* Depends on stepped_breakpoint. */ step = currently_stepping (tp); @@ -2265,6 +2392,7 @@ resume (enum gdb_signal sig) resume_ptid = user_visible_resume_ptid (user_step); do_target_resume (resume_ptid, 0, GDB_SIGNAL_0); discard_cleanups (old_cleanups); + tp->resumed = 1; return; } } @@ -2390,11 +2518,12 @@ resume (enum gdb_signal sig) if (execution_direction != EXEC_REVERSE && step && breakpoint_inserted_here_p (aspace, pc)) { - /* The only case we currently need to step a breakpoint - instruction is when we have a signal to deliver. See - handle_signal_stop where we handle random signals that could - take out us out of the stepping range. Normally, in that - case we end up continuing (instead of stepping) over the + /* There are two cases where we currently need to step a + breakpoint instruction when we have a signal to deliver: + + - See handle_signal_stop where we handle random signals that + could take out us out of the stepping range. Normally, in + that case we end up continuing (instead of stepping) over the signal handler with a breakpoint at PC, but there are cases where we should _always_ single-step, even if we have a step-resume breakpoint, like when a software watchpoint is @@ -2407,8 +2536,20 @@ resume (enum gdb_signal sig) recurses and executes PC again, it'll miss the breakpoint. So we leave the breakpoint inserted anyway, but we need to record that we tried to step a breakpoint instruction, so - that adjust_pc_after_break doesn't end up confused. */ - gdb_assert (sig != GDB_SIGNAL_0); + that adjust_pc_after_break doesn't end up confused. + + - In non-stop if we insert a breakpoint (e.g., a step-resume) + in one thread after another thread that was stepping had been + momentarily paused for a step-over. When we re-resume the + stepping thread, it may be resumed from that address with a + breakpoint that hasn't trapped yet. Seen with + gdb.threads/non-stop-fair-events.exp, on targets that don't + do displaced stepping. */ + + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: resume: [%s] stepped breakpoint\n", + target_pid_to_str (tp->ptid)); tp->stepped_breakpoint = 1; @@ -2446,6 +2587,7 @@ resume (enum gdb_signal sig) } do_target_resume (resume_ptid, step, sig); + tp->resumed = 1; discard_cleanups (old_cleanups); } @@ -2462,6 +2604,37 @@ clear_proceed_status_thread (struct thread_info *tp) "infrun: clear_proceed_status_thread (%s)\n", target_pid_to_str (tp->ptid)); + /* If we're starting a new sequence, then the previous finished + single-step is no longer relevant. */ + if (tp->suspend.waitstatus_pending_p) + { + if (tp->suspend.stop_reason == TARGET_STOPPED_BY_SINGLE_STEP) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: clear_proceed_status: pending " + "event of %s was a finished step. " + "Discarding.\n", + target_pid_to_str (tp->ptid)); + + tp->suspend.waitstatus_pending_p = 0; + tp->suspend.stop_reason = TARGET_STOPPED_BY_NO_REASON; + } + else if (debug_infrun) + { + char *statstr; + + statstr = target_waitstatus_to_string (&tp->suspend.waitstatus); + fprintf_unfiltered (gdb_stdlog, + "infrun: clear_proceed_status_thread: thread %s " + "has pending wait status %s " + "(currently_stepping=%d).\n", + target_pid_to_str (tp->ptid), statstr, + currently_stepping (tp)); + xfree (statstr); + } + } + /* If this signal should not be seen by program, give it zero. Used for debugging signals. */ if (!signal_pass_state (tp->suspend.stop_signal)) @@ -2525,8 +2698,6 @@ clear_proceed_status (int step) stop_after_trap = 0; - clear_step_over_info (); - observer_notify_about_to_proceed (); } @@ -2769,7 +2940,7 @@ proceed (CORE_ADDR addr, enum gdb_signal siggnal) /* A new displaced stepping sequence was started. In all-stop, we can't talk to the target anymore until it next stops. */ } - else if (!tp->executing && !thread_is_in_step_over_chain (tp)) + else if (!tp->resumed && !thread_is_in_step_over_chain (tp)) { /* The thread wasn't started, and isn't queued, run it now. */ reset_ecs (ecs, tp); @@ -3068,6 +3239,179 @@ print_target_wait_results (ptid_t waiton_ptid, ptid_t result_ptid, ui_file_delete (tmp_stream); } +/* Select a thread at random, out of those which are resumed and have + had events. */ + +static struct thread_info * +random_pending_event_thread (ptid_t waiton_ptid) +{ + struct thread_info *event_tp; + int num_events = 0; + int random_selector; + + /* First see how many events we have. Count only resumed threads + that have an event pending. */ + ALL_NON_EXITED_THREADS (event_tp) + if (ptid_match (event_tp->ptid, waiton_ptid) + && event_tp->resumed + && event_tp->suspend.waitstatus_pending_p) + num_events++; + + if (num_events == 0) + return NULL; + + /* Now randomly pick a thread out of those that have had events. */ + random_selector = (int) + ((num_events * (double) rand ()) / (RAND_MAX + 1.0)); + + if (debug_infrun && num_events > 1) + fprintf_unfiltered (gdb_stdlog, + "infrun: Found %d events, selecting #%d\n", + num_events, random_selector); + + /* Select the Nth thread that has had an event. */ + ALL_NON_EXITED_THREADS (event_tp) + if (ptid_match (event_tp->ptid, waiton_ptid) + && event_tp->resumed + && event_tp->suspend.waitstatus_pending_p) + if (random_selector-- == 0) + break; + + return event_tp; +} + +/* Wrapper for target_wait that first checks whether threads have + pending statuses to report before actually asking the target for + more events. */ + +static ptid_t +do_target_wait (ptid_t ptid, struct target_waitstatus *status, int options) +{ + ptid_t event_ptid; + struct thread_info *tp; + + /* First check if there is a resumed thread with a wait status + pending. */ + if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid)) + { + tp = random_pending_event_thread (ptid); + } + else + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: Waiting for specific thread %s.\n", + target_pid_to_str (ptid)); + + /* We have a specific thread to check. */ + tp = find_thread_ptid (ptid); + gdb_assert (tp != NULL); + if (!tp->suspend.waitstatus_pending_p) + tp = NULL; + } + + if (tp != NULL + && (tp->suspend.stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT + || tp->suspend.stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)) + { + struct regcache *regcache = get_thread_regcache (tp->ptid); + struct gdbarch *gdbarch = get_regcache_arch (regcache); + CORE_ADDR pc; + int discard = 0; + + pc = regcache_read_pc (regcache); + + if (pc != tp->suspend.stop_pc) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: PC of %s changed. was=%s, now=%s\n", + target_pid_to_str (tp->ptid), + paddress (gdbarch, tp->prev_pc), + paddress (gdbarch, pc)); + discard = 1; + } + else if (!breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc)) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: previous breakpoint of %s, at %s gone\n", + target_pid_to_str (tp->ptid), + paddress (gdbarch, pc)); + + discard = 1; + } + + if (discard) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: pending event of %s cancelled.\n", + target_pid_to_str (tp->ptid)); + + tp->suspend.waitstatus.kind = TARGET_WAITKIND_SPURIOUS; + tp->suspend.stop_reason = TARGET_STOPPED_BY_NO_REASON; + } + } + + if (tp != NULL) + { + if (debug_infrun) + { + char *statstr; + + statstr = target_waitstatus_to_string (&tp->suspend.waitstatus); + fprintf_unfiltered (gdb_stdlog, + "infrun: Using pending wait status %s for %s.\n", + statstr, + target_pid_to_str (tp->ptid)); + xfree (statstr); + } + + /* Now that we've selected our final event LWP, un-adjust its PC + if it was a software breakpoint (and the target doesn't + always adjust the PC itself). */ + if (tp->suspend.stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT + && !target_supports_stopped_by_sw_breakpoint ()) + { + struct regcache *regcache; + struct gdbarch *gdbarch; + int decr_pc; + + regcache = get_thread_regcache (tp->ptid); + gdbarch = get_regcache_arch (regcache); + + decr_pc = gdbarch_decr_pc_after_break (gdbarch); + if (decr_pc != 0) + { + CORE_ADDR pc; + + pc = regcache_read_pc (regcache); + regcache_write_pc (regcache, pc + decr_pc); + } + } + + tp->suspend.stop_reason = TARGET_STOPPED_BY_NO_REASON; + *status = tp->suspend.waitstatus; + tp->suspend.waitstatus_pending_p = 0; + + /* Wake up the event loop again, until all pending events are + processed. */ + if (target_is_async_p ()) + mark_async_event_handler (infrun_async_inferior_event_token); + return tp->ptid; + } + + /* But if we don't find one, we'll have to wait. */ + + if (deprecated_target_wait_hook) + event_ptid = deprecated_target_wait_hook (ptid, status, options); + else + event_ptid = target_wait (ptid, status, options); + + return event_ptid; +} + /* Prepare and stabilize the inferior for detaching it. E.g., detaching while a thread is displaced stepping is a recipe for crashing it, as nothing would readjust the PC out of the scratch @@ -3111,10 +3455,7 @@ prepare_for_detach (void) don't get any event. */ target_dcache_invalidate (); - if (deprecated_target_wait_hook) - ecs->ptid = deprecated_target_wait_hook (pid_ptid, &ecs->ws, 0); - else - ecs->ptid = target_wait (pid_ptid, &ecs->ws, 0); + ecs->ptid = do_target_wait (pid_ptid, &ecs->ws, 0); if (debug_infrun) print_target_wait_results (pid_ptid, ecs->ptid, &ecs->ws); @@ -3186,10 +3527,7 @@ wait_for_inferior (void) don't get any event. */ target_dcache_invalidate (); - if (deprecated_target_wait_hook) - ecs->ptid = deprecated_target_wait_hook (waiton_ptid, &ecs->ws, 0); - else - ecs->ptid = target_wait (waiton_ptid, &ecs->ws, 0); + ecs->ptid = do_target_wait (waiton_ptid, &ecs->ws, 0); if (debug_infrun) print_target_wait_results (waiton_ptid, ecs->ptid, &ecs->ws); @@ -3286,11 +3624,7 @@ fetch_inferior_event (void *client_data) make_cleanup_restore_integer (&execution_direction); execution_direction = target_execution_direction (); - if (deprecated_target_wait_hook) - ecs->ptid = - deprecated_target_wait_hook (waiton_ptid, &ecs->ws, TARGET_WNOHANG); - else - ecs->ptid = target_wait (waiton_ptid, &ecs->ws, TARGET_WNOHANG); + ecs->ptid = do_target_wait (waiton_ptid, &ecs->ws, TARGET_WNOHANG); if (debug_infrun) print_target_wait_results (waiton_ptid, ecs->ptid, &ecs->ws); @@ -3663,6 +3997,347 @@ get_inferior_stop_soon (ptid_t ptid) return inf->control.stop_soon; } +/* Wait for one event. Store the resulting waitstatus in WS, and + return the event ptid. */ + +static ptid_t +wait_one (struct target_waitstatus *ws) +{ + ptid_t event_ptid; + ptid_t wait_ptid = minus_one_ptid; + + overlay_cache_invalid = 1; + + /* Flush target cache before starting to handle each event. + Target was running and cache could be stale. This is just a + heuristic. Running threads may modify target memory, but we + don't get any event. */ + target_dcache_invalidate (); + + if (deprecated_target_wait_hook) + event_ptid = deprecated_target_wait_hook (wait_ptid, ws, 0); + else + event_ptid = target_wait (wait_ptid, ws, 0); + + if (debug_infrun) + print_target_wait_results (wait_ptid, event_ptid, ws); + + return event_ptid; +} + +/* Generate a wrapper for target_stopped_by_REASON that works on PTID + instead of the current thread. */ +#define THREAD_STOPPED_BY(REASON) \ +static int \ +thread_stopped_by_ ## REASON (ptid_t ptid) \ +{ \ + struct cleanup *old_chain; \ + int res; \ + \ + old_chain = save_inferior_ptid (); \ + inferior_ptid = ptid; \ + \ + res = target_stopped_by_ ## REASON (); \ + \ + do_cleanups (old_chain); \ + \ + return res; \ +} + +/* Generate thread_stopped_by_watchpoint. */ +THREAD_STOPPED_BY (watchpoint) +/* Generate thread_stopped_by_sw_breakpoint. */ +THREAD_STOPPED_BY (sw_breakpoint) +/* Generate thread_stopped_by_hw_breakpoint. */ +THREAD_STOPPED_BY (hw_breakpoint) + +/* Cleanups that switches to the PTID pointed at by PTID_P. */ + +static void +switch_to_thread_cleanup (void *ptid_p) +{ + ptid_t ptid = *(ptid_t *) ptid_p; + + switch_to_thread (ptid); +} + +/* Save the thread's event and stop reason to process it later. */ + +static void +save_waitstatus (struct thread_info *tp, struct target_waitstatus *ws) +{ + struct regcache *regcache; + struct address_space *aspace; + + if (debug_infrun) + { + char *statstr; + + statstr = target_waitstatus_to_string (ws); + fprintf_unfiltered (gdb_stdlog, + "infrun: saving status %s for %d.%ld.%ld\n", + statstr, + ptid_get_pid (tp->ptid), + ptid_get_lwp (tp->ptid), + ptid_get_tid (tp->ptid)); + xfree (statstr); + } + + /* Record for later. */ + tp->suspend.waitstatus = *ws; + tp->suspend.waitstatus_pending_p = 1; + + regcache = get_thread_regcache (tp->ptid); + aspace = get_regcache_aspace (regcache); + + if (ws->kind == TARGET_WAITKIND_STOPPED + && ws->value.sig == GDB_SIGNAL_TRAP) + { + CORE_ADDR pc = regcache_read_pc (regcache); + + adjust_pc_after_break (tp, &tp->suspend.waitstatus); + + if (thread_stopped_by_watchpoint (tp->ptid)) + { + tp->suspend.stop_reason + = TARGET_STOPPED_BY_WATCHPOINT; + } + else if (target_supports_stopped_by_sw_breakpoint () + && thread_stopped_by_sw_breakpoint (tp->ptid)) + { + tp->suspend.stop_reason + = TARGET_STOPPED_BY_SW_BREAKPOINT; + } + else if (target_supports_stopped_by_hw_breakpoint () + && thread_stopped_by_hw_breakpoint (tp->ptid)) + { + tp->suspend.stop_reason + = TARGET_STOPPED_BY_HW_BREAKPOINT; + } + else if (!target_supports_stopped_by_hw_breakpoint () + && hardware_breakpoint_inserted_here_p (aspace, + pc)) + { + tp->suspend.stop_reason + = TARGET_STOPPED_BY_HW_BREAKPOINT; + } + else if (!target_supports_stopped_by_sw_breakpoint () + && software_breakpoint_inserted_here_p (aspace, + pc)) + { + tp->suspend.stop_reason + = TARGET_STOPPED_BY_SW_BREAKPOINT; + } + else if (!thread_has_single_step_breakpoints_set (tp) + && currently_stepping (tp)) + { + tp->suspend.stop_reason + = TARGET_STOPPED_BY_SINGLE_STEP; + } + } +} + +/* Stop all threads. */ + +static void +stop_all_threads (void) +{ + /* We may need multiple passes to discover all threads. */ + int pass; + int iterations = 0; + ptid_t entry_ptid; + struct cleanup *old_chain; + + gdb_assert (non_stop); + + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, "infrun: stop_all_threads\n"); + + entry_ptid = inferior_ptid; + old_chain = make_cleanup (switch_to_thread_cleanup, &entry_ptid); + + /* Request threads to stop, and then wait for the stops. Because + threads we already know about can spawn more threads while we're + trying to stop them, and we only learn about new threads when we + update the thread list, do this in a loop, and keep iterating + until two passes find no threads that need to be stopped. */ + for (pass = 0; pass < 2; pass++, iterations++) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: stop_all_threads, pass=%d, " + "iterations=%d\n", pass, iterations); + while (1) + { + ptid_t event_ptid; + struct target_waitstatus ws; + int need_wait = 0; + struct thread_info *t; + + update_thread_list (); + + /* Go through all threads looking for threads that we need + to tell the target to stop. */ + ALL_NON_EXITED_THREADS (t) + { + if (t->executing) + { + /* If already stopping, don't request a stop again. + We just haven't seen the notification yet. */ + if (!t->stop_requested) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: %s executing, " + "need stop\n", + target_pid_to_str (t->ptid)); + target_stop (t->ptid); + t->stop_requested = 1; + } + else + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: %s executing, " + "already stopping\n", + target_pid_to_str (t->ptid)); + } + + if (t->stop_requested) + need_wait = 1; + } + else + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: %s not executing\n", + target_pid_to_str (t->ptid)); + + /* The thread may be not executing, but still be + resumed with a pending status to process. */ + t->resumed = 0; + } + } + + if (!need_wait) + break; + + /* If we find new threads on the second iteration, restart + over. We want to see two iterations in a row with all + threads stopped. */ + if (pass > 0) + pass = -1; + + event_ptid = wait_one (&ws); + if (ws.kind == TARGET_WAITKIND_NO_RESUMED) + { + /* All resumed threads exited. */ + } + else if (ws.kind == TARGET_WAITKIND_EXITED + || ws.kind == TARGET_WAITKIND_SIGNALLED) + { + if (debug_infrun) + { + ptid_t ptid = pid_to_ptid (ws.value.integer); + + fprintf_unfiltered (gdb_stdlog, + "infrun: %s exited while " + "stopping threads\n", + target_pid_to_str (ptid)); + } + } + else + { + t = find_thread_ptid (event_ptid); + if (t == NULL) + t = add_thread (event_ptid); + + t->stop_requested = 0; + t->executing = 0; + t->resumed = 0; + t->control.may_range_step = 0; + + if (ws.kind == TARGET_WAITKIND_STOPPED + && ws.value.sig == GDB_SIGNAL_0) + { + /* We caught the event that we intended to catch, so + there's no event pending. */ + t->suspend.waitstatus.kind = TARGET_WAITKIND_IGNORE; + t->suspend.waitstatus_pending_p = 0; + + if (displaced_step_fixup (t->ptid, GDB_SIGNAL_0) < 0) + { + /* Add it back to the step-over queue. */ + if (debug_infrun) + { + fprintf_unfiltered (gdb_stdlog, + "infrun: displaced-step of %s " + "canceled: adding back to the " + "step-over queue\n", + target_pid_to_str (t->ptid)); + } + t->control.trap_expected = 0; + thread_step_over_chain_enqueue (t); + } + } + else + { + enum gdb_signal sig; + struct regcache *regcache; + struct address_space *aspace; + + if (debug_infrun) + { + char *statstr; + + statstr = target_waitstatus_to_string (&ws); + fprintf_unfiltered (gdb_stdlog, + "infrun: target_wait %s, saving " + "status for %d.%ld.%ld\n", + statstr, + ptid_get_pid (t->ptid), + ptid_get_lwp (t->ptid), + ptid_get_tid (t->ptid)); + xfree (statstr); + } + + /* Record for later. */ + save_waitstatus (t, &ws); + + sig = (ws.kind == TARGET_WAITKIND_STOPPED + ? ws.value.sig : GDB_SIGNAL_0); + + if (displaced_step_fixup (t->ptid, sig) < 0) + { + /* Add it back to the step-over queue. */ + t->control.trap_expected = 0; + thread_step_over_chain_enqueue (t); + } + + regcache = get_thread_regcache (t->ptid); + t->suspend.stop_pc = regcache_read_pc (regcache); + + if (debug_infrun) + { + fprintf_unfiltered (gdb_stdlog, + "infrun: saved stop_pc=%s for %s " + "(currently_stepping=%d)\n", + paddress (target_gdbarch (), + t->suspend.stop_pc), + target_pid_to_str (t->ptid), + currently_stepping (t)); + } + } + } + } + } + + do_cleanups (old_chain); + + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, "infrun: stop_all_threads done\n"); +} + /* 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. @@ -3782,31 +4457,38 @@ handle_inferior_event_1 (struct execution_control_state *ecs) /* Mark the non-executing threads accordingly. In all-stop, all threads of all processes are stopped when we get any event reported. In non-stop mode, only the event thread stops. */ - if (!non_stop) - set_executing (minus_one_ptid, 0); - else if (ecs->ws.kind == TARGET_WAITKIND_SIGNALLED - || ecs->ws.kind == TARGET_WAITKIND_EXITED) - { - ptid_t pid_ptid; - - /* If we're handling a process exit in non-stop mode, even - though threads haven't been deleted yet, one would think that - there is nothing to do, as threads of the dead process will - be soon deleted, and threads of any other process were left - running. However, on some targets, threads survive a process - exit event. E.g., for the "checkpoint" command, when the - current checkpoint/fork exits, linux-fork.c automatically - switches to another fork from within target_mourn_inferior, - by associating the same inferior/thread to another fork. We - haven't mourned yet at this point, but we must mark any - threads left in the process as not-executing so that - finish_thread_state marks them stopped (in the user's - perspective) if/when we present the stop to the user. */ - pid_ptid = pid_to_ptid (ptid_get_pid (ecs->ptid)); - set_executing (pid_ptid, 0); - } - else - set_executing (ecs->ptid, 0); + { + ptid_t mark_ptid; + + if (!non_stop) + mark_ptid = minus_one_ptid; + else if (ecs->ws.kind == TARGET_WAITKIND_SIGNALLED + || ecs->ws.kind == TARGET_WAITKIND_EXITED) + { + /* If we're handling a process exit in non-stop mode, even + though threads haven't been deleted yet, one would think + that there is nothing to do, as threads of the dead process + will be soon deleted, and threads of any other process were + left running. However, on some targets, threads survive a + process exit event. E.g., for the "checkpoint" command, + when the current checkpoint/fork exits, linux-fork.c + automatically switches to another fork from within + target_mourn_inferior, by associating the same + inferior/thread to another fork. We haven't mourned yet at + this point, but we must mark any threads left in the + process as not-executing so that finish_thread_state marks + them stopped (in the user's perspective) if/when we present + the stop to the user. */ + mark_ptid = pid_to_ptid (ptid_get_pid (ecs->ptid)); + } + else + mark_ptid = ecs->ptid; + + set_executing (mark_ptid, 0); + + /* Likewise the resumed flag. */ + set_resumed (mark_ptid, 0); + } switch (ecs->ws.kind) { @@ -4235,16 +4917,137 @@ handle_inferior_event (struct execution_control_state *ecs) value_free_to_mark (mark); } -/* Called when we get an event that may finish an in-line or - out-of-line (displaced stepping) step-over started previously. */ +/* Restart threads back to what they were trying to do back when we + paused them for an in-line step-over. The EVENT_THREAD thread is + ignored. */ static void +restart_threads (struct thread_info *event_thread) +{ + struct thread_info *tp; + struct thread_info *step_over = NULL; + + /* In case the instruction just stepped spawned a new thread. */ + update_thread_list (); + + ALL_NON_EXITED_THREADS (tp) + { + if (tp == event_thread) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: restart threads: " + "[%s] is event thread\n", + target_pid_to_str (tp->ptid)); + continue; + } + + if (!(tp->state == THREAD_RUNNING || tp->control.in_infcall)) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: restart threads: " + "[%s] not meant to be running\n", + target_pid_to_str (tp->ptid)); + continue; + } + + if (tp->resumed) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: restart threads: [%s] resumed\n", + target_pid_to_str (tp->ptid)); + gdb_assert (tp->executing || tp->suspend.waitstatus_pending_p); + continue; + } + + if (thread_is_in_step_over_chain (tp)) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: restart threads: " + "[%s] needs step-over\n", + target_pid_to_str (tp->ptid)); + gdb_assert (!tp->resumed); + continue; + } + + + if (tp->suspend.waitstatus_pending_p) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: restart threads: " + "[%s] has pending status\n", + target_pid_to_str (tp->ptid)); + tp->resumed = 1; + continue; + } + + /* If some thread needs to start a step-over at this point, it + should still be in the step-over queue, and thus skipped + above. */ + if (thread_still_needs_step_over (tp)) + { + internal_error (__FILE__, __LINE__, + "thread [%s] needs a step-over, but not in " + "step-over queue\n", + target_pid_to_str (tp->ptid)); + } + + if (currently_stepping (tp)) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: restart threads: [%s] was stepping\n", + target_pid_to_str (tp->ptid)); + keep_going_stepped_thread (tp); + } + else + { + struct execution_control_state ecss; + struct execution_control_state *ecs = &ecss; + + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: restart threads: [%s] continuing\n", + target_pid_to_str (tp->ptid)); + reset_ecs (ecs, tp); + switch_to_thread (tp->ptid); + keep_going_pass_signal (ecs); + } + } +} + +/* Callback for iterate_over_threads. Find a resumed thread that has + a pending waitstatus. */ + +static int +resumed_thread_with_pending_status (struct thread_info *tp, + void *arg) +{ + return (tp->resumed + && tp->suspend.waitstatus_pending_p); +} + +/* Called when we get an event that may finish an in-line or + out-of-line (displaced stepping) step-over started previously. + Return true if the event is processed and we should go back to the + event loop; false if the caller should continue processing the + event. */ + +static int finish_step_over (struct execution_control_state *ecs) { + int had_step_over_info; + displaced_step_fixup (ecs->ptid, ecs->event_thread->suspend.stop_signal); - if (step_over_info_valid_p ()) + had_step_over_info = step_over_info_valid_p (); + + if (had_step_over_info) { /* If we're stepping over a breakpoint with all threads locked, then only the thread that was stepped should be reporting @@ -4256,11 +5059,99 @@ finish_step_over (struct execution_control_state *ecs) } if (!non_stop) - return; + return 0; /* Start a new step-over in another thread if there's one that needs it. */ start_step_over (); + + /* If we were stepping over a breakpoint before, and haven't started + a new in-line step-over sequence, then restart all other threads + (except the event thread). We can't do this in all-stop, as then + e.g., we wouldn't be able to issue any other remote packet until + these other threads stop. */ + if (had_step_over_info && !step_over_info_valid_p ()) + { + struct thread_info *pending; + + /* If we only have threads with pending statuses, the restart + below won't restart any thread and so nothing re-inserts the + breakpoint we just stepped over. But we need it inserted + when we later process the pending events, otherwise if + another thread has a pending event for this breakpoint too, + we'd discard its event (because the breakpoint that + originally caused the event was no longer inserted). */ + context_switch (ecs->ptid); + insert_breakpoints (); + + restart_threads (ecs->event_thread); + + /* If we have events pending, go through handle_inferior_event + again, picking up a pending event at random. This avoids + thread starvation. */ + + /* But not if we just stepped over a watchpoint in order to let + the instruction execute so we can evaluate its expression. + The set of watchpoints that triggered is recorded in the + breakpoint objects themselves (see bp->watchpoint_triggered). + If we processed another event first, that other event could + clobber this info. */ + if (ecs->event_thread->stepping_over_watchpoint) + return 0; + + pending = iterate_over_threads (resumed_thread_with_pending_status, + NULL); + if (pending != NULL) + { + struct thread_info *tp = ecs->event_thread; + struct regcache *regcache; + + if (debug_infrun) + { + fprintf_unfiltered (gdb_stdlog, + "infrun: found resumed threads with " + "pending events, saving status\n"); + } + + gdb_assert (pending != tp); + + /* Record the event thread's event for later. */ + save_waitstatus (tp, &ecs->ws); + /* This was cleared early, by handle_inferior_event. Set it + so this pending event is considered by + do_target_wait. */ + tp->resumed = 1; + + gdb_assert (!tp->executing); + + regcache = get_thread_regcache (tp->ptid); + tp->suspend.stop_pc = regcache_read_pc (regcache); + + if (debug_infrun) + { + fprintf_unfiltered (gdb_stdlog, + "infrun: saved stop_pc=%s for %s " + "(currently_stepping=%d)\n", + paddress (target_gdbarch (), + tp->suspend.stop_pc), + target_pid_to_str (tp->ptid), + currently_stepping (tp)); + } + + /* This in-line step-over finished; clear this so we won't + start a new one. This is what handle_signal_stop would + do, if we returned false. */ + tp->stepping_over_breakpoint = 0; + + /* Wake up the event loop again. */ + mark_async_event_handler (infrun_async_inferior_event_token); + + prepare_to_wait (ecs); + return 1; + } + } + + return 0; } /* Come here when the program has stopped with a signal. */ @@ -4279,7 +5170,8 @@ handle_signal_stop (struct execution_control_state *ecs) /* Do we need to clean up the state of a thread that has completed a displaced single-step? (Doing so usually affects the PC, so do it here, before we set stop_pc.) */ - finish_step_over (ecs); + if (finish_step_over (ecs)) + return; /* If we either finished a single-step or hit a breakpoint, but the user wanted this thread to be stopped, pretend we got a @@ -4722,6 +5614,8 @@ handle_signal_stop (struct execution_control_state *ecs) && ecs->event_thread->control.trap_expected && ecs->event_thread->control.step_resume_breakpoint == NULL) { + int was_in_line; + /* We were just starting a new sequence, attempting to single-step off of a breakpoint and expecting a SIGTRAP. Instead this signal arrives. This signal will take us out @@ -4737,11 +5631,32 @@ handle_signal_stop (struct execution_control_state *ecs) "infrun: signal arrived while stepping over " "breakpoint\n"); + was_in_line = step_over_info_valid_p (); + clear_step_over_info (); insert_hp_step_resume_breakpoint_at_frame (frame); ecs->event_thread->step_after_step_resume_breakpoint = 1; /* Reset trap_expected to ensure breakpoints are re-inserted. */ ecs->event_thread->control.trap_expected = 0; + if (non_stop) + { + keep_going (ecs); + + /* The step-over has been canceled temporarily while the + signal handler executes. */ + if (was_in_line) + { + /* We had paused all threads, restart them. */ + restart_threads (ecs->event_thread); + } + else if (debug_infrun) + { + fprintf_unfiltered (gdb_stdlog, + "infrun: no need to restart threads\n"); + } + return; + } + /* If we were nexting/stepping some other thread, switch to it, so that we don't continue it, losing control. */ if (!switch_back_to_stepped_thread (ecs)) @@ -4770,6 +5685,7 @@ handle_signal_stop (struct execution_control_state *ecs) "infrun: signal may take us out of " "single-step range\n"); + clear_step_over_info (); insert_hp_step_resume_breakpoint_at_frame (frame); ecs->event_thread->step_after_step_resume_breakpoint = 1; /* Reset trap_expected to ensure breakpoints are re-inserted. */ @@ -5725,7 +6641,14 @@ switch_back_to_stepped_thread (struct execution_control_state *ecs) except the one that needs to move past the breakpoint. If a non-event thread has this set, the "incomplete step-over" check above should have caught it earlier. */ - gdb_assert (!tp->control.trap_expected); + if (tp->control.trap_expected) + { + internal_error (__FILE__, __LINE__, + "[%s] has inconsistent state: " + "trap_expected=%d\n", + target_pid_to_str (tp->ptid), + tp->control.trap_expected); + } /* Did we find the stepping thread? */ if (tp->control.step_range_end) @@ -5854,6 +6777,7 @@ keep_going_stepped_thread (struct thread_info *tp) get_frame_address_space (frame), stop_pc); + tp->resumed = 1; resume_ptid = user_visible_resume_ptid (tp->control.stepping_command); do_target_resume (resume_ptid, 0, GDB_SIGNAL_0); } @@ -6288,6 +7212,7 @@ keep_going_pass_signal (struct execution_control_state *ecs) struct cleanup *old_cleanups = make_cleanup (resume_cleanups, 0); gdb_assert (ptid_equal (ecs->event_thread->ptid, inferior_ptid)); + gdb_assert (!ecs->event_thread->resumed); /* Save the pc before execution, to compare with pc after stop. */ ecs->event_thread->prev_pc @@ -6310,6 +7235,34 @@ keep_going_pass_signal (struct execution_control_state *ecs) discard_cleanups (old_cleanups); resume (ecs->event_thread->suspend.stop_signal); } + else if (step_over_info_valid_p ()) + { + /* Another thread is stepping over a breakpoint in-line. If + this thread needs a step-over too, queue the request. In + either case, this resume must be deferred for later. */ + struct thread_info *tp = ecs->event_thread; + + if (ecs->hit_singlestep_breakpoint + || thread_still_needs_step_over (tp)) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: step-over already in progress: " + "step-over for %s deferred\n", + target_pid_to_str (tp->ptid)); + thread_step_over_chain_enqueue (tp); + } + else + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: step-over in progress: " + "resume of %s deferred\n", + target_pid_to_str (tp->ptid)); + } + + discard_cleanups (old_cleanups); + } else { struct regcache *regcache = get_current_regcache (); @@ -6354,8 +7307,14 @@ keep_going_pass_signal (struct execution_control_state *ecs) } else if (remove_wps) set_step_over_info (NULL, 0, remove_wps); - else - clear_step_over_info (); + + /* If we now need to do an in-line step-over, we need to stop + all other threads. Note this must be done before + insert_breakpoints below, because that removes the breakpoint + we're about to step over, otherwise other threads could miss + it. */ + if (step_over_info_valid_p () && non_stop) + stop_all_threads (); /* Stop stepping if inserting breakpoints fails. */ TRY @@ -7696,6 +8655,23 @@ static const struct internalvar_funcs siginfo_funcs = NULL }; +/* Callback for infrun's target events source. This is marked when a + thread has a pending status to process. */ + +static void +infrun_async_inferior_event_handler (gdb_client_data data) +{ + /* If the target is closed while this event source is marked, we + will reach here without execution, or a target to call + target_wait on, which is an error. Instead of tracking whether + the target has been popped already, or whether we do have threads + with pending statutes, simply ignore the event. */ + if (!target_is_async_p ()) + return; + + inferior_event_handler (INF_REG_EVENT, NULL); +} + void _initialize_infrun (void) { @@ -7703,6 +8679,10 @@ _initialize_infrun (void) int numsigs; struct cmd_list_element *c; + /* Register extra event sources in the event loop. */ + infrun_async_inferior_event_token + = create_async_event_handler (infrun_async_inferior_event_handler, NULL); + add_info ("signals", signals_info, _("\ What debugger does when program gets various signals.\n\ Specify a signal as argument to print info on that signal only.")); |