Destroy allocated values when exiting GDB

When the user exits GDB, we might still have some allocated values in
the chain, which, in specific scenarios, can cause problems when GDB
attempts to destroy them in "quit_force".  For example, see the bug
reported at:

  https://bugzilla.redhat.com/show_bug.cgi?id=1690120

And the thread starting at:

  https://sourceware.org/ml/gdb-patches/2019-03/msg00475.html
  Message-ID: <87r2azkhmq.fsf@redhat.com>

In order to avoid that, and to be more aware of our allocated
resources, this commit implements a new function "finalize_values" and
calls it from inside "quit_force".

Tested by the BuildBot.

2019-04-01  Sergio Durigan Junior  <sergiodj@redhat.com>
	    Pedro Alves  <palves@redhat.com>

	* top.c (quit_force): Call 'finalize_values'.
	* value.c (finalize_values): New function.
	* value.h (finalize_values): Declare.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index a3dfd3169873113365687defd15902e7d8ffe730..3de5992d87bd86456876b48c0b37e2e02a061e15 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2019-04-01  Sergio Durigan Junior  <sergiodj@redhat.com>
+           Pedro Alves  <palves@redhat.com>
+
+       * top.c (quit_force): Call 'finalize_values'.
+       * value.c (finalize_values): New function.
+       * value.h (finalize_values): Declare.
+
 2019-03-30  Eli Zaretskii  <eliz@gnu.org>
 
        * NEWS: Announce $_gdb_major and $_gdb_minor.

diff --git a/gdb/top.c b/gdb/top.c
index afb77c0ec956f40726a33d0c987e8e4fe22c39a0..1fc259fe0f487a208bc4fcbba782f34847e94b64 100644 (file)
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -1673,6 +1673,12 @@ quit_force (int *exit_arg, int from_tty)
     }
   END_CATCH
 
+  /* Destroy any values currently allocated now instead of leaving it
+     to global destructors, because that may be too late.  For
+     example, the destructors of xmethod values call into the Python
+     runtime, which is finalized via a final cleanup.  */
+  finalize_values ();
+
   /* Do any final cleanups before exiting.  */
   TRY
     {

diff --git a/gdb/value.c b/gdb/value.c
index dc297dfe0f9efaf827c84b58107c1e4a2d87141b..bcfc084e09092a187baa691856f7b3f940573073 100644 (file)
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -4132,3 +4132,11 @@ prevents future values, larger than this size, from being allocated."),
                            selftests::test_insert_into_bit_range_vector);
 #endif
 }
+
+/* See value.h.  */
+
+void
+finalize_values ()
+{
+  all_values.clear ();
+}

diff --git a/gdb/value.h b/gdb/value.h
index d3905cc354a775dd4c97ed558f4933e058f782de..0756d13b6d79f060e9ada774518092e49ec1a9d4 100644 (file)
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -1189,4 +1189,8 @@ extern struct value *call_xmethod (struct value *method,
 extern int value_union_variant (struct type *union_type,
                                const gdb_byte *contents);
 
+/* Destroy the values currently allocated.  This is called when GDB is
+   exiting (e.g., on quit_force).  */
+extern void finalize_values ();
+
 #endif /* !defined (VALUE_H) */