RFC: fix archive refcounting in gdb
Tom Tromey
tromey@redhat.com
Fri Aug 3 15:02:00 GMT 2012
I just sent some BFD patches to fix some bugs in BFD regarding memory
management of archive member BFDs.
This patch changs gdb to follow the newly-documented best pratice for
such BFDs: if a member BFD is in use, the archive BFD must be kept
alive. In gdb terms, this is easily implemented by having an archive
member BFD keep a reference to the archive BFD.
I'd like to check this in after the BFD patches go in.
* gdb_bfd.c (struct gdb_bfd_data) <archive_bfd>: New field.
(gdb_bfd_ref): Initialize new field.
(gdb_bfd_unref): Unref the archive BFD.
(gdb_bfd_openr_next_archived_file): Acquire a reference to the
parent archive.
---
gdb/gdb_bfd.c | 19 ++++++++++++++++++-
1 files changed, 18 insertions(+), 1 deletions(-)
diff --git a/gdb/gdb_bfd.c b/gdb/gdb_bfd.c
index 40e1c4d..266272d 100644
--- a/gdb/gdb_bfd.c
+++ b/gdb/gdb_bfd.c
@@ -81,6 +81,10 @@ struct gdb_bfd_data
/* The mtime of the BFD at the point the cache entry was made. */
time_t mtime;
+
+ /* If the BFD comes from an archive, this points to the archive's
+ BFD. Otherwise, this is NULL. */
+ bfd *archive_bfd;
};
/* A hash table storing all the BFDs maintained in the cache. */
@@ -249,6 +253,7 @@ gdb_bfd_ref (struct bfd *abfd)
gdata = bfd_zalloc (abfd, sizeof (struct gdb_bfd_data));
gdata->refc = 1;
gdata->mtime = bfd_get_mtime (abfd);
+ gdata->archive_bfd = NULL;
bfd_usrdata (abfd) = gdata;
/* This is the first we've seen it, so add it to the hash table. */
@@ -265,6 +270,7 @@ gdb_bfd_unref (struct bfd *abfd)
struct gdb_bfd_data *gdata;
struct gdb_bfd_cache_search search;
void **slot;
+ bfd *archive_bfd;
if (abfd == NULL)
return;
@@ -276,6 +282,7 @@ gdb_bfd_unref (struct bfd *abfd)
if (gdata->refc > 0)
return;
+ archive_bfd = gdata->archive_bfd;
search.filename = bfd_get_filename (abfd);
if (gdb_bfd_cache && search.filename)
@@ -296,6 +303,8 @@ gdb_bfd_unref (struct bfd *abfd)
htab_remove_elt (all_bfds, abfd);
gdb_bfd_close_or_warn (abfd);
+
+ gdb_bfd_unref (archive_bfd);
}
/* A helper function that returns the section data descriptor
@@ -591,8 +600,16 @@ gdb_bfd_openr_next_archived_file (bfd *archive, bfd *previous)
if (result)
{
+ struct gdb_bfd_data *gdata;
+
gdb_bfd_ref (result);
- /* No need to stash the filename here. */
+ /* No need to stash the filename here, because we also keep a
+ reference on the parent archive. */
+
+ gdata = bfd_usrdata (result);
+ gdb_assert (gdata->archive_bfd == NULL || gdata->archive_bfd == archive);
+ gdata->archive_bfd = archive;
+ gdb_bfd_ref (archive);
}
return result;
--
1.7.7.6
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