[PATCH 2/3] btrace: Remove VEC cleanups

Simon Marchi
2018-03-04T20:56:17Z

This patch replaces two VEC(tp_t) with std::vector<thread_info *>, which
allows to remove two cleanups. To make it easier to map the old code to
the new code, I added the ordered_remove and unordered_remove functions,
which operate on std::vector and do the same as VEC's
ordered_remove/unordered_remove.

gdb/ChangeLog:

* record-btrace.c (record_btrace_maybe_mark_async_event): Change
parameter types to std::vector. Use bool.
(record_btrace_wait): Replace VEC(tp_t) with
std::vector<thread_info *>.
* common/gdb_vecs.h (unordered_remove, ordered_remove): New.
---
gdb/common/gdb_vecs.h | 31 +++++++++++++++++++++++
gdb/record-btrace.c | 68 +++++++++++++++++++++++++--------------------------
2 files changed, 64 insertions(+), 35 deletions(-)

diff --git a/gdb/common/gdb_vecs.h b/gdb/common/gdb_vecs.h
index 29db27a892..7318e53132 100644
--- a/gdb/common/gdb_vecs.h
+++ b/gdb/common/gdb_vecs.h
@@ -50,4 +50,35 @@ extern void dirnames_to_char_ptr_vec_append
extern std::vector<gdb::unique_xmalloc_ptr<char>>
dirnames_to_char_ptr_vec (const char *dirnames);

+/* Remove the element at position IX from VEC, not preserving the order of the
+ remaining elements. Return the removed element. */
+
+template <typename T>
+T
+unordered_remove (std::vector<T> &vec, typename std::vector<T>::size_type ix)
+{
+ gdb_assert (ix < vec.size ());
+
+ T removed = std::move (vec[ix]);
+ vec[ix] = std::move (vec.back ());
+ vec.pop_back ();
+
+ return removed;
+}
+
+/* Remove the element at position IX from VEC, preserving the order the
+ remaining elements. Return the removed element. */
+
+template <typename T>
+T
+ordered_remove (std::vector<T> &vec, typename std::vector<T>::size_type ix)
+{
+ gdb_assert (ix < vec.size ());
+
+ T removed = std::move (vec[ix]);
+ vec.erase (vec.begin () + ix);
+
+ return removed;
+}
+
#endif /* GDB_VECS_H */
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index b04a7e5049..15ce760f5a 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -2428,13 +2428,12 @@ DEF_VEC_P (tp_t);
/* Announce further events if necessary. */

static void
-record_btrace_maybe_mark_async_event (const VEC (tp_t) *moving,
- const VEC (tp_t) *no_history)
+record_btrace_maybe_mark_async_event
+ (const std::vector<thread_info *> &moving,
+ const std::vector<thread_info *> &no_history)
{
- int more_moving, more_no_history;
-
- more_moving = !VEC_empty (tp_t, moving);
- more_no_history = !VEC_empty (tp_t, no_history);
+ bool more_moving = !moving.empty ();
+ bool more_no_history = !no_history.empty ();;

if (!more_moving && !more_no_history)
return;
@@ -2454,9 +2453,8 @@ static ptid_t
record_btrace_wait (struct target_ops *ops, ptid_t ptid,
struct target_waitstatus *status, int options)
{
- VEC (tp_t) *moving, *no_history;
- struct thread_info *tp, *eventing;
- struct cleanup *cleanups = make_cleanup (null_cleanup, NULL);
+ std::vector<thread_info *> moving;
+ std::vector<thread_info *> no_history;

DEBUG ("wait %s (0x%x)", target_pid_to_str (ptid), options);

@@ -2468,26 +2466,25 @@ record_btrace_wait (struct target_ops *ops, ptid_t ptid,
return ops->to_wait (ops, ptid, status, options);
}

- 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);
+ {
+ thread_info *tp;
+
+ ALL_NON_EXITED_THREADS (tp)
+ {
+ if (ptid_match (tp->ptid, ptid)
+ && ((tp->btrace.flags & (BTHR_MOVE | BTHR_STOP)) != 0))
+ moving.push_back (tp);
+ }
+ }

- if (VEC_empty (tp_t, moving))
+ if (moving.empty ())
{
*status = btrace_step_no_resumed ();

DEBUG ("wait ended by %s: %s", target_pid_to_str (null_ptid),
target_waitstatus_to_string (status).c_str ());

- do_cleanups (cleanups);
return null_ptid;
}

@@ -2508,14 +2505,13 @@ record_btrace_wait (struct target_ops *ops, ptid_t ptid,
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))
+ struct thread_info *eventing = NULL;
+ while ((eventing == NULL) && !moving.empty ())
{
- unsigned int ix;
-
- ix = 0;
- while ((eventing == NULL) && VEC_iterate (tp_t, moving, ix, tp))
+ for (unsigned int ix = 0; eventing == NULL && ix < moving.size ();)
{
+ thread_info *tp = moving[ix];
+
*status = record_btrace_step_thread (tp);

switch (status->kind)
@@ -2525,12 +2521,11 @@ record_btrace_wait (struct target_ops *ops, ptid_t ptid,
break;

case TARGET_WAITKIND_NO_HISTORY:
- VEC_safe_push (tp_t, no_history,
- VEC_ordered_remove (tp_t, moving, ix));
+ no_history.push_back (ordered_remove (moving, ix));
break;

default:
- eventing = VEC_unordered_remove (tp_t, moving, ix);
+ eventing = unordered_remove (moving, ix);
break;
}
}
@@ -2543,11 +2538,11 @@ record_btrace_wait (struct target_ops *ops, ptid_t ptid,

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));
+ gdb_assert (!no_history.empty ());

/* 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 = unordered_remove (no_history, 0);
eventing->btrace.flags &= ~BTHR_MOVE;

*status = btrace_step_no_history ();
@@ -2561,8 +2556,12 @@ record_btrace_wait (struct target_ops *ops, ptid_t ptid,

/* Stop all other threads. */
if (!target_is_non_stop_p ())
- ALL_NON_EXITED_THREADS (tp)
- record_btrace_cancel_resume (tp);
+ {
+ thread_info *tp;
+
+ ALL_NON_EXITED_THREADS (tp)
+ record_btrace_cancel_resume (tp);
+ }

/* In async mode, we need to announce further events. */
if (target_is_async_p ())
@@ -2579,7 +2578,6 @@ record_btrace_wait (struct target_ops *ops, ptid_t ptid,
target_pid_to_str (eventing->ptid),
target_waitstatus_to_string (status).c_str ());

- do_cleanups (cleanups);
return eventing->ptid;
}

--
2.16.1