btrace: Remove VEC cleanups

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.

1 files changed, 31 insertions, 0 deletions

diff --git a/gdb/common/gdb_vecs.h b/gdb/common/gdb_vecs.h
index 29db27a..7318e53 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 */