Commit Message
Pedro Alves <palves@redhat.com> writes:
> On 01/20/2015 06:26 AM, Doug Evans wrote:
>> Hi.
>>
>> This patch fixes symtab/17855.
>> Basically the issue is that breakpoint_re_set is currently being called
>> before observer_notify_new_objfile (NULL), and thus the ada symbol
>> cache (and the general symbol cache of a separate patch) aren't being
>> flushed first, so that when breakpoints are reset symbol lookup is being
>> done on a stale cache.
>>
>> Regression tested on amd64-linux.
>>
>> 2015-01-19 Doug Evans <xdje42@gmail.com>
>>
>> PR symtab/17855
>> * symfile.c (clear_symtab_users): Notify observers of change before
>> calling breakpoint_re_set.
>>
>> diff --git a/gdb/symfile.c b/gdb/symfile.c
>> index d55e361..ad481de 100644
>> --- a/gdb/symfile.c
>> +++ b/gdb/symfile.c
>> @@ -3023,6 +3023,12 @@ clear_symtab_users (int add_flags)
>> /* Someday, we should do better than this, by only blowing away
>> the things that really need to be blown. */
>>
>> + /* Notify anyone listening that the previous loaded symtab(s) are invalid.
>> + It is important to do this before calling breakpoint_re_set as the latter
>> + will try to look up symbols, and for example the symbol cache needs to
>> + be flushed first. */
>> + observer_notify_new_objfile (NULL);
>> +
>> /* Clear the "current" symtab first, because it is no longer valid.
>> breakpoint_re_set may try to access the current symtab. */
>> clear_current_source_symtab_and_line ();
>> @@ -3032,7 +3038,6 @@ clear_symtab_users (int add_flags)
>> breakpoint_re_set ();
>> clear_last_displayed_sal ();
>> clear_pc_function_cache ();
>> - observer_notify_new_objfile (NULL);
>
> Looking at the whole function, ISTM that the breakpoint_re_set
> call should move further down. I can imagine that breakpoint_re_set
> could well hit a stale pc function cache, cleared only after by
> clear_pc_function_cache. breakpoint.c:parse_breakpoint_sals also
> references the last displayed sal. One would hope that breakpoint
> re-set is independent of that, though the existing comment about
> breakpoint_re_set accessing the current symtab leaves me
> wondering. WDYT?
>
> Thanks,
> Pedro Alves
Like so?
2015-01-28 Doug Evans <xdje42@gmail.com>
PR symtab/17855
* symfile.c (clear_symtab_users): Move call to breakpoint_re_set
closer to end.
@@ -3023,13 +3023,8 @@ clear_symtab_users (int add_flags)
/* Someday, we should do better than this, by only blowing away
the things that really need to be blown. */
- /* Clear the "current" symtab first, because it is no longer valid.
- breakpoint_re_set may try to access the current symtab. */
clear_current_source_symtab_and_line ();
-
clear_displays ();
- if ((add_flags & SYMFILE_DEFER_BP_RESET) == 0)
- breakpoint_re_set ();
clear_last_displayed_sal ();
clear_pc_function_cache ();
observer_notify_new_objfile (NULL);
@@ -3040,9 +3035,19 @@ clear_symtab_users (int add_flags)
expression_context_block = NULL;
innermost_block = NULL;
+ /* Now that most everything has been reset, reset any existing breakpoints.
+ Reasons for doing this after the above are that breakpoint resetting may
+ involve:
+ - reading the current source symtab and line,
+ - reading the last displayed sal,
+ - reading the pc function cache,
+ - symbol lookup which requires, for example, invalidating any caches
+ first. */
+ if ((add_flags & SYMFILE_DEFER_BP_RESET) == 0)
+ breakpoint_re_set ();
+
/* Varobj may refer to old symbols, perform a cleanup. */
varobj_invalidate ();
-
}
static void