#include "infrun.h"
#include "event-loop.h"
#include "inf-loop.h"
+#include "vec.h"
/* The target_ops of record-btrace. */
static struct target_ops record_btrace_ops;
btinfo = &tp->btrace;
- if ((btinfo->flags & BTHR_MOVE) != 0)
- error (_("Thread already moving."));
-
/* Fetch the latest branch trace. */
btrace_fetch (tp);
- /* A resume request overwrites a preceding stop request. */
- btinfo->flags &= ~BTHR_STOP;
+ /* A resume request overwrites a preceding resume or stop request. */
+ btinfo->flags &= ~(BTHR_MOVE | BTHR_STOP);
btinfo->flags |= flag;
}
-/* Find the thread to resume given a PTID. */
+/* Get the current frame for TP. */
-static struct thread_info *
-record_btrace_find_resume_thread (ptid_t ptid)
+static struct frame_info *
+get_thread_current_frame (struct thread_info *tp)
{
- struct thread_info *tp;
+ struct frame_info *frame;
+ ptid_t old_inferior_ptid;
+ int executing;
+
+ /* Set INFERIOR_PTID, which is implicitly used by get_current_frame. */
+ old_inferior_ptid = inferior_ptid;
+ inferior_ptid = tp->ptid;
- /* When asked to resume everything, we pick the current thread. */
- if (ptid_equal (minus_one_ptid, ptid) || ptid_is_pid (ptid))
- ptid = inferior_ptid;
+ /* Clear the executing flag to allow changes to the current frame.
+ We are not actually running, yet. We just started a reverse execution
+ command or a record goto command.
+ For the latter, EXECUTING is false and this has no effect.
+ For the former, EXECUTING is true and we're in to_wait, about to
+ move the thread. Since we need to recompute the stack, we temporarily
+ set EXECUTING to flase. */
+ executing = is_executing (inferior_ptid);
+ set_executing (inferior_ptid, 0);
- return find_thread_ptid (ptid);
+ frame = NULL;
+ TRY
+ {
+ frame = get_current_frame ();
+ }
+ CATCH (except, RETURN_MASK_ALL)
+ {
+ /* Restore the previous execution state. */
+ set_executing (inferior_ptid, executing);
+
+ /* Restore the previous inferior_ptid. */
+ inferior_ptid = old_inferior_ptid;
+
+ throw_exception (except);
+ }
+ END_CATCH
+
+ /* Restore the previous execution state. */
+ set_executing (inferior_ptid, executing);
+
+ /* Restore the previous inferior_ptid. */
+ inferior_ptid = old_inferior_ptid;
+
+ return frame;
}
/* Start replaying a thread. */
{
struct btrace_insn_iterator *replay;
struct btrace_thread_info *btinfo;
- int executing;
btinfo = &tp->btrace;
replay = NULL;
if (btinfo->begin == NULL)
return NULL;
- /* Clear the executing flag to allow changes to the current frame.
- We are not actually running, yet. We just started a reverse execution
- command or a record goto command.
- For the latter, EXECUTING is false and this has no effect.
- For the former, EXECUTING is true and we're in to_wait, about to
- move the thread. Since we need to recompute the stack, we temporarily
- set EXECUTING to flase. */
- executing = is_executing (tp->ptid);
- set_executing (tp->ptid, 0);
-
/* GDB stores the current frame_id when stepping in order to detects steps
into subroutines.
Since frames are computed differently when we're replaying, we need to
int upd_step_frame_id, upd_step_stack_frame_id;
/* The current frame without replaying - computed via normal unwind. */
- frame = get_current_frame ();
+ frame = get_thread_current_frame (tp);
frame_id = get_frame_id (frame);
/* Check if we need to update any stepping-related frame id's. */
registers_changed_ptid (tp->ptid);
/* The current frame with replaying - computed via btrace unwind. */
- frame = get_current_frame ();
+ frame = get_thread_current_frame (tp);
frame_id = get_frame_id (frame);
/* Replace stepping related frames where necessary. */
}
CATCH (except, RETURN_MASK_ALL)
{
- /* Restore the previous execution state. */
- set_executing (tp->ptid, executing);
-
xfree (btinfo->replay);
btinfo->replay = NULL;
}
END_CATCH
- /* Restore the previous execution state. */
- set_executing (tp->ptid, executing);
-
return replay;
}
registers_changed_ptid (tp->ptid);
}
+/* Stop replaying TP if it is at the end of its execution history. */
+
+static void
+record_btrace_stop_replaying_at_end (struct thread_info *tp)
+{
+ struct btrace_insn_iterator *replay, end;
+ struct btrace_thread_info *btinfo;
+
+ btinfo = &tp->btrace;
+ replay = btinfo->replay;
+
+ if (replay == NULL)
+ return;
+
+ btrace_insn_end (&end, btinfo);
+
+ if (btrace_insn_cmp (replay, &end) == 0)
+ record_btrace_stop_replaying (tp);
+}
+
/* The to_resume method of target record-btrace. */
static void
record_btrace_resume (struct target_ops *ops, ptid_t ptid, int step,
enum gdb_signal signal)
{
- struct thread_info *tp, *other;
+ struct thread_info *tp;
enum btrace_thread_flag flag;
+ ptid_t orig_ptid;
DEBUG ("resume %s: %s%s", target_pid_to_str (ptid),
execution_direction == EXEC_REVERSE ? "reverse-" : "",
step ? "step" : "cont");
- /* Store the execution direction of the last resume. */
+ orig_ptid = ptid;
+
+ /* Store the execution direction of the last resume.
+
+ If there is more than one to_resume call, we have to rely on infrun
+ to not change the execution direction in-between. */
record_btrace_resume_exec_dir = execution_direction;
- tp = record_btrace_find_resume_thread (ptid);
- if (tp == NULL)
- error (_("Cannot find thread to resume."));
+ /* For all-stop targets... */
+ if (!target_is_non_stop_p ())
+ {
+ /* ...we pick the current thread when asked to resume an entire process
+ or everything. */
+ if (ptid_equal (minus_one_ptid, ptid) || ptid_is_pid (ptid))
+ ptid = inferior_ptid;
+
+ tp = find_thread_ptid (ptid);
+ if (tp == NULL)
+ error (_("Cannot find thread to resume."));
+
+ /* ...and we stop replaying other threads if the thread to resume is not
+ replaying. */
+ if (!btrace_is_replaying (tp) && execution_direction != EXEC_REVERSE)
+ ALL_NON_EXITED_THREADS (tp)
+ record_btrace_stop_replaying (tp);
+ }
- /* Stop replaying other threads if the thread to resume is not replaying. */
- if (!btrace_is_replaying (tp) && execution_direction != EXEC_REVERSE)
- ALL_NON_EXITED_THREADS (other)
- record_btrace_stop_replaying (other);
+ /* As long as we're not replaying, just forward the request.
- /* As long as we're not replaying, just forward the request. */
+ For non-stop targets this means that no thread is replaying. In order to
+ make progress, we may need to explicitly move replaying threads to the end
+ of their execution history. */
if (!record_btrace_is_replaying (ops) && execution_direction != EXEC_REVERSE)
{
ops = ops->beneath;
- return ops->to_resume (ops, ptid, step, signal);
+ return ops->to_resume (ops, orig_ptid, step, signal);
}
/* Compute the btrace thread flag for the requested move. */
else
flag = execution_direction == EXEC_REVERSE ? BTHR_RSTEP : BTHR_STEP;
- /* At the moment, we only move a single thread. We could also move
- all threads in parallel by single-stepping each resumed thread
- until the first runs into an event.
- When we do that, we would want to continue all other threads.
- For now, just resume one thread to not confuse to_wait. */
- record_btrace_resume_thread (tp, flag);
-
/* We just indicate the resume intent here. The actual stepping happens in
record_btrace_wait below. */
+ ALL_NON_EXITED_THREADS (tp)
+ if (ptid_match (tp->ptid, ptid))
+ record_btrace_resume_thread (tp, flag);
/* Async support. */
if (target_can_async_p ())
btrace_thread_flag_to_str (flags));
tp->btrace.flags &= ~(BTHR_MOVE | BTHR_STOP);
-}
-
-/* Find a thread to move. */
-
-static struct thread_info *
-record_btrace_find_thread_to_move (ptid_t ptid)
-{
- struct thread_info *tp;
-
- /* First check the parameter thread. */
- tp = find_thread_ptid (ptid);
- if (tp != NULL && (tp->btrace.flags & (BTHR_MOVE | BTHR_STOP)) != 0)
- return tp;
-
- /* Otherwise, find one other thread that has been resumed. */
- ALL_NON_EXITED_THREADS (tp)
- if ((tp->btrace.flags & (BTHR_MOVE | BTHR_STOP)) != 0)
- return tp;
-
- return NULL;
+ record_btrace_stop_replaying_at_end (tp);
}
/* Return a target_waitstatus indicating that we ran out of history. */
return status;
}
+/* Return a target_waitstatus indicating that the thread was not resumed. */
+
+static struct target_waitstatus
+btrace_step_no_resumed (void)
+{
+ struct target_waitstatus status;
+
+ status.kind = TARGET_WAITKIND_NO_RESUMED;
+
+ return status;
+}
+
+/* Return a target_waitstatus indicating that we should wait again. */
+
+static struct target_waitstatus
+btrace_step_again (void)
+{
+ struct target_waitstatus status;
+
+ status.kind = TARGET_WAITKIND_IGNORE;
+
+ return status;
+}
+
/* Clear the record histories. */
static void
if (replay == NULL)
return btrace_step_no_history ();
+ /* Check if we're stepping a breakpoint. */
+ if (record_btrace_replay_at_breakpoint (tp))
+ return btrace_step_stopped ();
+
/* Skip gaps during replay. */
do
{
unsigned int steps;
+ /* We will bail out here if we continue stepping after reaching the end
+ of the execution history. */
steps = btrace_insn_next (replay, 1);
if (steps == 0)
- {
- record_btrace_stop_replaying (tp);
- return btrace_step_no_history ();
- }
+ return btrace_step_no_history ();
}
while (btrace_insn_get (replay) == NULL);
/* Determine the end of the instruction trace. */
btrace_insn_end (&end, btinfo);
- /* We stop replaying if we reached the end of the trace. */
+ /* The execution trace contains (and ends with) the current instruction.
+ This instruction has not been executed, yet, so the trace really ends
+ one instruction earlier. */
if (btrace_insn_cmp (replay, &end) == 0)
- record_btrace_stop_replaying (tp);
+ return btrace_step_no_history ();
return btrace_step_spurious ();
}
}
while (btrace_insn_get (replay) == NULL);
+ /* Check if we're stepping a breakpoint.
+
+ For reverse-stepping, this check is after the step. There is logic in
+ infrun.c that handles reverse-stepping separately. See, for example,
+ proceed and adjust_pc_after_break.
+
+ This code assumes that for reverse-stepping, PC points to the last
+ de-executed instruction, whereas for forward-stepping PC points to the
+ next to-be-executed instruction. */
+ if (record_btrace_replay_at_breakpoint (tp))
+ return btrace_step_stopped ();
+
return btrace_step_spurious ();
}
case BTHR_STEP:
status = record_btrace_single_step_forward (tp);
if (status.kind != TARGET_WAITKIND_SPURIOUS)
- return status;
+ break;
return btrace_step_stopped ();
case BTHR_RSTEP:
status = record_btrace_single_step_backward (tp);
if (status.kind != TARGET_WAITKIND_SPURIOUS)
- return status;
+ break;
return btrace_step_stopped ();
case BTHR_CONT:
- for (;;)
- {
- status = record_btrace_single_step_forward (tp);
- if (status.kind != TARGET_WAITKIND_SPURIOUS)
- return status;
-
- if (btinfo->replay != NULL)
- {
- const struct btrace_insn *insn;
-
- insn = btrace_insn_get (btinfo->replay);
- gdb_assert (insn != NULL);
-
- DEBUG ("stepping %d (%s) ... %s", tp->num,
- target_pid_to_str (tp->ptid),
- core_addr_to_string_nz (insn->pc));
- }
+ status = record_btrace_single_step_forward (tp);
+ if (status.kind != TARGET_WAITKIND_SPURIOUS)
+ break;
- if (record_btrace_replay_at_breakpoint (tp))
- return btrace_step_stopped ();
- }
+ btinfo->flags |= flags;
+ return btrace_step_again ();
case BTHR_RCONT:
- for (;;)
- {
- const struct btrace_insn *insn;
+ status = record_btrace_single_step_backward (tp);
+ if (status.kind != TARGET_WAITKIND_SPURIOUS)
+ break;
- status = record_btrace_single_step_backward (tp);
- if (status.kind != TARGET_WAITKIND_SPURIOUS)
- return status;
+ btinfo->flags |= flags;
+ return btrace_step_again ();
+ }
- gdb_assert (btinfo->replay != NULL);
+ /* We keep threads moving at the end of their execution history. The to_wait
+ method will stop the thread for whom the event is reported. */
+ if (status.kind == TARGET_WAITKIND_NO_HISTORY)
+ btinfo->flags |= flags;
- insn = btrace_insn_get (btinfo->replay);
- gdb_assert (insn != NULL);
+ return status;
+}
- DEBUG ("reverse-stepping %d (%s) ... %s", tp->num,
- target_pid_to_str (tp->ptid),
- core_addr_to_string_nz (insn->pc));
+/* A vector of threads. */
- if (record_btrace_replay_at_breakpoint (tp))
- return btrace_step_stopped ();
- }
- }
-}
+typedef struct thread_info * tp_t;
+DEF_VEC_P (tp_t);
/* The to_wait method of target record-btrace. */
record_btrace_wait (struct target_ops *ops, ptid_t ptid,
struct target_waitstatus *status, int options)
{
- struct thread_info *tp, *other;
+ VEC (tp_t) *moving, *no_history;
+ struct thread_info *tp, *eventing;
+ struct cleanup *cleanups = make_cleanup (null_cleanup, NULL);
DEBUG ("wait %s (0x%x)", target_pid_to_str (ptid), options);
return ops->to_wait (ops, ptid, status, options);
}
- /* Let's find a thread to move. */
- tp = record_btrace_find_thread_to_move (ptid);
- if (tp == NULL)
+ moving = NULL;
+ no_history = NULL;
+
+ make_cleanup (VEC_cleanup (tp_t), &moving);
+ make_cleanup (VEC_cleanup (tp_t), &no_history);
+
+ /* Keep a work list of moving threads. */
+ ALL_NON_EXITED_THREADS (tp)
+ if (ptid_match (tp->ptid, ptid)
+ && ((tp->btrace.flags & (BTHR_MOVE | BTHR_STOP)) != 0))
+ VEC_safe_push (tp_t, moving, tp);
+
+ if (VEC_empty (tp_t, moving))
{
- DEBUG ("wait %s: no thread", target_pid_to_str (ptid));
+ *status = btrace_step_no_resumed ();
- status->kind = TARGET_WAITKIND_IGNORE;
- return minus_one_ptid;
+ DEBUG ("wait ended by %s: %s", target_pid_to_str (null_ptid),
+ target_waitstatus_to_string (status));
+
+ do_cleanups (cleanups);
+ return null_ptid;
}
- /* We only move a single thread. We're not able to correlate threads. */
- *status = record_btrace_step_thread (tp);
+ /* Step moving threads one by one, one step each, until either one thread
+ reports an event or we run out of threads to step.
+
+ When stepping more than one thread, chances are that some threads reach
+ the end of their execution history earlier than others. If we reported
+ this immediately, all-stop on top of non-stop would stop all threads and
+ resume the same threads next time. And we would report the same thread
+ having reached the end of its execution history again.
+
+ In the worst case, this would starve the other threads. But even if other
+ threads would be allowed to make progress, this would result in far too
+ many intermediate stops.
+
+ We therefore delay the reporting of "no execution history" until we have
+ nothing else to report. By this time, all threads should have moved to
+ either the beginning or the end of their execution history. There will
+ be a single user-visible stop. */
+ eventing = NULL;
+ while ((eventing == NULL) && !VEC_empty (tp_t, moving))
+ {
+ unsigned int ix;
+
+ ix = 0;
+ while ((eventing == NULL) && VEC_iterate (tp_t, moving, ix, tp))
+ {
+ *status = record_btrace_step_thread (tp);
+
+ switch (status->kind)
+ {
+ case TARGET_WAITKIND_IGNORE:
+ ix++;
+ break;
+
+ case TARGET_WAITKIND_NO_HISTORY:
+ VEC_safe_push (tp_t, no_history,
+ VEC_ordered_remove (tp_t, moving, ix));
+ break;
+
+ default:
+ eventing = VEC_unordered_remove (tp_t, moving, ix);
+ break;
+ }
+ }
+ }
+
+ if (eventing == NULL)
+ {
+ /* We started with at least one moving thread. This thread must have
+ either stopped or reached the end of its execution history.
+
+ In the former case, EVENTING must not be NULL.
+ In the latter case, NO_HISTORY must not be empty. */
+ gdb_assert (!VEC_empty (tp_t, no_history));
+
+ /* We kept threads moving at the end of their execution history. Stop
+ EVENTING now that we are going to report its stop. */
+ eventing = VEC_unordered_remove (tp_t, no_history, 0);
+ eventing->btrace.flags &= ~BTHR_MOVE;
+
+ *status = btrace_step_no_history ();
+ }
+
+ gdb_assert (eventing != NULL);
+
+ /* We kept threads replaying at the end of their execution history. Stop
+ replaying EVENTING now that we are going to report its stop. */
+ record_btrace_stop_replaying_at_end (eventing);
/* Stop all other threads. */
if (!target_is_non_stop_p ())
- ALL_NON_EXITED_THREADS (other)
- record_btrace_cancel_resume (other);
+ ALL_NON_EXITED_THREADS (tp)
+ record_btrace_cancel_resume (tp);
/* Start record histories anew from the current position. */
- record_btrace_clear_histories (&tp->btrace);
+ record_btrace_clear_histories (&eventing->btrace);
/* We moved the replay position but did not update registers. */
- registers_changed_ptid (tp->ptid);
+ registers_changed_ptid (eventing->ptid);
+
+ DEBUG ("wait ended by thread %d (%s): %s", eventing->num,
+ target_pid_to_str (eventing->ptid),
+ target_waitstatus_to_string (status));
- return tp->ptid;
+ do_cleanups (cleanups);
+ return eventing->ptid;
}
/* The to_stop method of target record-btrace. */
projects / deliverable / binutils-gdb.git / blobdiff