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* [binutils-gdb] gdb: call frame unwinders' dealloc_cache methods through destroying the frame cache
@ 2023-02-08 21:39 Simon Marchi
0 siblings, 0 replies; only message in thread
From: Simon Marchi @ 2023-02-08 21:39 UTC (permalink / raw)
To: gdb-cvs
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=6d3717d4c412db52b33fa53f0ea9fc52f3d0aadc
commit 6d3717d4c412db52b33fa53f0ea9fc52f3d0aadc
Author: Simon Marchi <simon.marchi@efficios.com>
Date: Mon Jan 30 15:02:48 2023 -0500
gdb: call frame unwinders' dealloc_cache methods through destroying the frame cache
Currently, some frame resources are deallocated by iterating on the
frame chain (starting from the sentinel), calling dealloc_cache. The
problem is that user-created frames are not part of that chain, so we
never call dealloc_cache for them.
I propose to make it so the dealloc_cache callbacks are called when the
frames are removed from the frame_stash hash table, by registering a
deletion function to the hash table. This happens when
frame_stash_invalidate is called by reinit_frame_cache. This way, all
frames registered in the cache will get their unwinder's dealloc_cache
callbacks called.
Note that at the moment, the sentinel frames are not registered in the
cache, so we won't call dealloc_cache for them. However, it's just a
theoritical problem, because the sentinel frame unwinder does not
provide this callback. Also, a subsequent patch will change things so
that sentinel frames are registered to the cache.
I moved the obstack_free / obstack_init pair below the
frame_stash_invalidate call in reinit_frame_cache, because I assumed
that some dealloc_cache would need to access some data on that obstack,
so it would be better to free it after clearing the hash table.
Change-Id: If4f9b38266b458c4e2f7eb43e933090177c22190
Diff:
---
gdb/frame.c | 39 ++++++++++++++++++++++++---------------
1 file changed, 24 insertions(+), 15 deletions(-)
diff --git a/gdb/frame.c b/gdb/frame.c
index a08a8f47ebc..fed961b2a8d 100644
--- a/gdb/frame.c
+++ b/gdb/frame.c
@@ -259,6 +259,22 @@ frame_addr_hash_eq (const void *a, const void *b)
return f_entry->this_id.value == f_element->this_id.value;
}
+/* Deletion function for the frame cache hash table. */
+
+static void
+frame_info_del (void *frame_v)
+{
+ frame_info *frame = (frame_info *) frame_v;
+
+ if (frame->prologue_cache != nullptr
+ && frame->unwind->dealloc_cache != nullptr)
+ frame->unwind->dealloc_cache (frame, frame->prologue_cache);
+
+ if (frame->base_cache != nullptr
+ && frame->base->unwind->dealloc_cache != nullptr)
+ frame->base->unwind->dealloc_cache (frame, frame->base_cache);
+}
+
/* Internal function to create the frame_stash hash table. 100 seems
to be a good compromise to start the hash table at. */
@@ -268,7 +284,7 @@ frame_stash_create (void)
frame_stash = htab_create (100,
frame_addr_hash,
frame_addr_hash_eq,
- NULL);
+ frame_info_del);
}
/* Internal function to add a frame to the frame_stash hash table.
@@ -2048,26 +2064,19 @@ reinit_frame_cache (void)
{
++frame_cache_generation;
- /* Tear down all frame caches. */
- for (frame_info *fi = sentinel_frame; fi != NULL; fi = fi->prev)
- {
- if (fi->prologue_cache && fi->unwind->dealloc_cache)
- fi->unwind->dealloc_cache (fi, fi->prologue_cache);
- if (fi->base_cache && fi->base->unwind->dealloc_cache)
- fi->base->unwind->dealloc_cache (fi, fi->base_cache);
- }
-
- /* Since we can't really be sure what the first object allocated was. */
- obstack_free (&frame_cache_obstack, 0);
- obstack_init (&frame_cache_obstack);
-
if (sentinel_frame != NULL)
annotate_frames_invalid ();
- sentinel_frame = NULL; /* Invalidate cache */
invalidate_selected_frame ();
+
+ /* Invalidate cache. */
+ sentinel_frame = NULL;
frame_stash_invalidate ();
+ /* Since we can't really be sure what the first object allocated was. */
+ obstack_free (&frame_cache_obstack, 0);
+ obstack_init (&frame_cache_obstack);
+
for (frame_info_ptr &iter : frame_info_ptr::frame_list)
iter.invalidate ();
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