gdb: Add debug tracing for bfd cache activity.

This patch adds a new debug flag bfd-cache, which when set to non-zero
produces debugging log messages relating to gdb's bfd cache.

gdb/ChangeLog:

	* gdb_bfd.c (debug_bfd_cache): New variable.
	(show_bfd_cache_debug): New function.
	(gdb_bfd_open): Add debug logging.
	(gdb_bfd_ref): Likewise.
	(gdb_bfd_unref): Likewise.
	(_initialize_gdb_bfd): Add new set/show command.
	* NEWS: Mention new command.

gdb/doc/ChangeLog:

	* gdb.texinfo (File Caching): Document "set/show debug bfd-cache".
This commit is contained in:
Andrew Burgess 2015-04-13 16:56:23 +01:00
parent 18989b3c56
commit 566f5e3b38
5 changed files with 78 additions and 1 deletions

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@ -1,3 +1,13 @@
2015-08-18 Andrew Burgess <andrew.burgess@embecosm.com>
* gdb_bfd.c (debug_bfd_cache): New variable.
(show_bfd_cache_debug): New function.
(gdb_bfd_open): Add debug logging.
(gdb_bfd_ref): Likewise.
(gdb_bfd_unref): Likewise.
(_initialize_gdb_bfd): Add new set/show command.
* NEWS: Mention new command.
2015-08-18 Andrew Burgess <andrew.burgess@embecosm.com>
* gdb_bfd.c (bfd_sharing): New variable.

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@ -24,6 +24,10 @@ maint set bfd-sharing
maint show bfd-sharing
Control the reuse of bfd objects.
set debug bfd-cache
show debug bfd-cache
Control display of debugging info regarding bfd caching.
* The "disassemble" command accepts a new modifier: /s.
It prints mixed source+disassembly like /m with two differences:
- disassembled instructions are now printed in program order, and

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@ -1,3 +1,7 @@
2015-08-18 Andrew Burgess <andrew.burgess@embecosm.com>
* gdb.texinfo (File Caching): Document "set/show debug bfd-cache".
2015-08-18 Andrew Burgess <andrew.burgess@embecosm.com>
* gdb.texinfo (Maintenance Commands): Move documentation of "main

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@ -18371,6 +18371,16 @@ already shared @code{bfd} objects to be unshared, but all future files
that are opened will create a new @code{bfd} object. Similarly,
re-enabling sharing does not cause multiple existing @code{bfd}
objects to be collapsed into a single shared @code{bfd} object.
@kindex set debug bfd-cache @var{level}
@kindex bfd caching
@item set debug bfd-cache @var{level}
Turns on debugging of the bfd cache, setting the level to @var{level}.
@kindex show debug bfd-cache
@kindex bfd caching
@item show debug bfd-cache
Show the current debugging level of the bfd cache.
@end table
@node Separate Debug Files

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@ -122,6 +122,16 @@ show_bfd_sharing (struct ui_file *file, int from_tty,
fprintf_filtered (file, _("BFD sharing is %s.\n"), value);
}
/* When non-zero debugging of the bfd caches is enabled. */
static unsigned int debug_bfd_cache;
static void
show_bfd_cache_debug (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
fprintf_filtered (file, _("BFD cache debugging is %s.\n"), value);
}
/* The type of an object being looked up in gdb_bfd_cache. We use
htab's capability of storing one kind of object (BFD in this case)
and using a different sort of object for searching. */
@ -407,6 +417,11 @@ gdb_bfd_open (const char *name, const char *target, int fd)
abfd = htab_find_with_hash (gdb_bfd_cache, &search, hash);
if (bfd_sharing && abfd != NULL)
{
if (debug_bfd_cache)
fprintf_unfiltered (gdb_stdlog,
"Reusing cached bfd %s for %s\n",
host_address_to_string (abfd),
bfd_get_filename (abfd));
close (fd);
gdb_bfd_ref (abfd);
return abfd;
@ -416,6 +431,12 @@ gdb_bfd_open (const char *name, const char *target, int fd)
if (abfd == NULL)
return NULL;
if (debug_bfd_cache)
fprintf_unfiltered (gdb_stdlog,
"Creating new bfd %s for %s\n",
host_address_to_string (abfd),
bfd_get_filename (abfd));
if (bfd_sharing)
{
slot = htab_find_slot_with_hash (gdb_bfd_cache, &search, hash, INSERT);
@ -484,6 +505,12 @@ gdb_bfd_ref (struct bfd *abfd)
gdata = bfd_usrdata (abfd);
if (debug_bfd_cache)
fprintf_unfiltered (gdb_stdlog,
"Increase reference count on bfd %s (%s)\n",
host_address_to_string (abfd),
bfd_get_filename (abfd));
if (gdata != NULL)
{
gdata->refc += 1;
@ -537,7 +564,20 @@ gdb_bfd_unref (struct bfd *abfd)
gdata->refc -= 1;
if (gdata->refc > 0)
return;
{
if (debug_bfd_cache)
fprintf_unfiltered (gdb_stdlog,
"Decrease reference count on bfd %s (%s)\n",
host_address_to_string (abfd),
bfd_get_filename (abfd));
return;
}
if (debug_bfd_cache)
fprintf_unfiltered (gdb_stdlog,
"Delete final reference count on bfd %s (%s)\n",
host_address_to_string (abfd),
bfd_get_filename (abfd));
archive_bfd = gdata->archive_bfd;
search.filename = bfd_get_filename (abfd);
@ -968,4 +1008,13 @@ filename, file size, file modification time, and file inode."),
&show_bfd_sharing,
&maintenance_set_cmdlist,
&maintenance_show_cmdlist);
add_setshow_zuinteger_cmd ("bfd-cache", class_maintenance,
&debug_bfd_cache, _("\
Set bfd cache debugging."), _("\
Show bfd cache debugging."), _("\
When non-zero, bfd cache specific debugging is enabled."),
NULL,
&show_bfd_cache_debug,
&setdebuglist, &showdebuglist);
}