diff options
Diffstat (limited to 'gdb/infrun.c')
| -rw-r--r-- | gdb/infrun.c | 66 |
1 files changed, 61 insertions, 5 deletions
diff --git a/gdb/infrun.c b/gdb/infrun.c index f1dbd11..7b1caee 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -469,6 +469,9 @@ static int singlestep_breakpoints_inserted_p = 0; /* The thread we inserted single-step breakpoints for. */ static ptid_t singlestep_ptid; +/* PC when we started this single-step. */ +static CORE_ADDR singlestep_pc; + /* If another thread hit the singlestep breakpoint, we save the original thread here so that we can resume single-stepping it later. */ static ptid_t saved_singlestep_ptid; @@ -563,6 +566,7 @@ resume (int step, enum target_signal sig) `wait_for_inferior' */ singlestep_breakpoints_inserted_p = 1; singlestep_ptid = inferior_ptid; + singlestep_pc = read_pc (); } /* If there were any forks/vforks/execs that were caught and are @@ -1126,6 +1130,14 @@ context_switch (struct execution_control_state *ecs) be lost. This may happen as a result of the target module mishandling thread creation. */ + if (debug_infrun) + { + fprintf_unfiltered (gdb_stdlog, "infrun: Switching context from %s ", + target_pid_to_str (inferior_ptid)); + fprintf_unfiltered (gdb_stdlog, "to %s\n", + target_pid_to_str (ecs->ptid)); + } + if (in_thread_list (inferior_ptid) && in_thread_list (ecs->ptid)) { /* Perform infrun state context switch: */ /* Save infrun state for the old thread. */ @@ -1149,6 +1161,7 @@ context_switch (struct execution_control_state *ecs) &ecs->current_line, &ecs->current_symtab); } inferior_ptid = ecs->ptid; + flush_cached_frames (); } static void @@ -1609,6 +1622,14 @@ handle_inferior_event (struct execution_control_state *ecs) } else if (SOFTWARE_SINGLE_STEP_P () && singlestep_breakpoints_inserted_p) { + /* We have not context switched yet, so this should be true + no matter which thread hit the singlestep breakpoint. */ + gdb_assert (ptid_equal (inferior_ptid, singlestep_ptid)); + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, "infrun: software single step " + "trap for %s\n", + target_pid_to_str (ecs->ptid)); + ecs->random_signal = 0; /* The call to in_thread_list is necessary because PTIDs sometimes change when we go from single-threaded to multi-threaded. If @@ -1617,9 +1638,46 @@ handle_inferior_event (struct execution_control_state *ecs) if (!ptid_equal (singlestep_ptid, ecs->ptid) && in_thread_list (singlestep_ptid)) { - thread_hop_needed = 1; - stepping_past_singlestep_breakpoint = 1; - saved_singlestep_ptid = singlestep_ptid; + /* If the PC of the thread we were trying to single-step + has changed, discard this event (which we were going + to ignore anyway), and pretend we saw that thread + trap. This prevents us continuously moving the + single-step breakpoint forward, one instruction at a + time. If the PC has changed, then the thread we were + trying to single-step has trapped or been signalled, + but the event has not been reported to GDB yet. + + There might be some cases where this loses signal + information, if a signal has arrived at exactly the + same time that the PC changed, but this is the best + we can do with the information available. Perhaps we + should arrange to report all events for all threads + when they stop, or to re-poll the remote looking for + this particular thread (i.e. temporarily enable + schedlock). */ + if (read_pc_pid (singlestep_ptid) != singlestep_pc) + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, "infrun: unexpected thread," + " but expected thread advanced also\n"); + + /* The current context still belongs to + singlestep_ptid. Don't swap here, since that's + the context we want to use. Just fudge our + state and continue. */ + ecs->ptid = singlestep_ptid; + stop_pc = read_pc_pid (ecs->ptid); + } + else + { + if (debug_infrun) + fprintf_unfiltered (gdb_stdlog, + "infrun: unexpected thread\n"); + + thread_hop_needed = 1; + stepping_past_singlestep_breakpoint = 1; + saved_singlestep_ptid = singlestep_ptid; + } } } @@ -1702,8 +1760,6 @@ handle_inferior_event (struct execution_control_state *ecs) if (deprecated_context_hook) deprecated_context_hook (pid_to_thread_id (ecs->ptid)); - - flush_cached_frames (); } if (SOFTWARE_SINGLE_STEP_P () && singlestep_breakpoints_inserted_p) |