[patch 2/3] Use gdb_realpath in gdb_bfd_open

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

it seems logical to always call gdb_realpath() in gdb_bfd_open(), IIRC also
suggested by Doug.  Currently all the callers already pass in
gdb_realpath()-canonicalized filenames but [patch 3/3] will change that.

This patch has no user visible effect (except for lower GDB performance).


Jan


gdb/
2013-08-28  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Use gdb_realpath in gdb_bfd_open.
	* gdb_bfd.c (struct gdb_bfd_data): Add field canonical_filename.
	(struct gdb_bfd_cache_search): Rename field filename to
	canonical_filename.
	(hash_bfd): New variable gdata.  Use gdata->canonical_filename.
	(eq_bfd): Use gdata->canonical_filename and
	gdb_bfd_cache_search::canonical_filename.
	(gdb_bfd_open): New variables canonical_name, canonical_name_copy and
	gdata.  Initialize canonical_name with gdb_realpath and use it.
	Call xfree for it when needed.  Store it also to
	gdata->canonical_filename.
	(gdb_bfd_ref): Set gdata->canonical_filename.
	(gdb_bfd_unref): Use gdata->canonical_filename.  Rename the use of
	struct gdb_bfd_cache_search.

--- a/gdb/gdb_bfd.c
+++ b/gdb/gdb_bfd.c
@@ -92,6 +92,11 @@ struct gdb_bfd_data
      BFD.  Otherwise, this is NULL.  */
   bfd *archive_bfd;
 
+  /* Filename used for lookups in gdb_bfd_cache.
+     It is only optionally canonical (by gdb_realpath), it may be also
+     just bfd_get_filename (abfd).  */
+  const char *canonical_filename;
+
   /* The registry.  */
   REGISTRY_FIELDS;
 };
@@ -112,7 +117,7 @@ static htab_t gdb_bfd_cache;
 struct gdb_bfd_cache_search
 {
   /* The filename.  */
-  const char *filename;
+  const char *canonical_filename;
   /* The mtime.  */
   time_t mtime;
 };
@@ -123,9 +128,10 @@ static hashval_t
 hash_bfd (const void *b)
 {
   const bfd *abfd = b;
+  struct gdb_bfd_data *gdata = bfd_usrdata (abfd);
 
   /* It is simplest to just hash the filename.  */
-  return htab_hash_string (bfd_get_filename (abfd));
+  return htab_hash_string (gdata->canonical_filename);
 }
 
 /* An equality function for BFDs.  Note that this expects the caller
@@ -139,7 +145,7 @@ eq_bfd (const void *a, const void *b)
   struct gdb_bfd_data *gdata = bfd_usrdata (abfd);
 
   return (gdata->mtime == s->mtime
-	  && strcmp (bfd_get_filename (abfd), s->filename) == 0);
+	  && strcmp (gdata->canonical_filename, s->canonical_filename) == 0);
 }
 
 /* See gdb_bfd.h.  */
@@ -152,6 +158,8 @@ gdb_bfd_open (const char *name, const char *target, int fd)
   bfd *abfd;
   struct gdb_bfd_cache_search search;
   struct stat st;
+  char *canonical_name, *canonical_name_copy;
+  struct gdb_bfd_data *gdata;
 
   if (gdb_bfd_cache == NULL)
     gdb_bfd_cache = htab_create_alloc (1, hash_bfd, eq_bfd, NULL,
@@ -167,7 +175,9 @@ gdb_bfd_open (const char *name, const char *target, int fd)
 	}
     }
 
-  search.filename = name;
+  canonical_name = gdb_realpath (name);
+
+  search.canonical_filename = canonical_name;
   if (fstat (fd, &st) < 0)
     {
       /* Weird situation here.  */
@@ -177,13 +187,14 @@ gdb_bfd_open (const char *name, const char *target, int fd)
     search.mtime = st.st_mtime;
 
   /* Note that this must compute the same result as hash_bfd.  */
-  hash = htab_hash_string (name);
+  hash = htab_hash_string (search.canonical_filename);
   /* Note that we cannot use htab_find_slot_with_hash here, because
      opening the BFD may fail; and this would violate hashtab
      invariants.  */
   abfd = htab_find_with_hash (gdb_bfd_cache, &search, hash);
   if (abfd != NULL)
     {
+      xfree (canonical_name);
       close (fd);
       gdb_bfd_ref (abfd);
       return abfd;
@@ -191,7 +202,10 @@ gdb_bfd_open (const char *name, const char *target, int fd)
 
   abfd = bfd_fopen (name, target, FOPEN_RB, fd);
   if (abfd == NULL)
-    return NULL;
+    {
+      xfree (canonical_name);
+      return NULL;
+    }
 
   slot = htab_find_slot_with_hash (gdb_bfd_cache, &search, hash, INSERT);
   gdb_assert (!*slot);
@@ -199,6 +213,14 @@ gdb_bfd_open (const char *name, const char *target, int fd)
 
   gdb_bfd_stash_filename (abfd);
   gdb_bfd_ref (abfd);
+
+  /* Store CANONICAL_NAME into gdata->canonical_filename.  */
+  gdata = bfd_usrdata (abfd);
+  canonical_name_copy = bfd_alloc (abfd, strlen (canonical_name) + 1);
+  strcpy (canonical_name_copy, canonical_name);
+  xfree (canonical_name);
+  gdata->canonical_filename = canonical_name_copy;
+
   return abfd;
 }
 
@@ -271,6 +293,7 @@ gdb_bfd_ref (struct bfd *abfd)
   gdata->refc = 1;
   gdata->mtime = bfd_get_mtime (abfd);
   gdata->archive_bfd = NULL;
+  gdata->canonical_filename = bfd_get_filename (abfd);
   bfd_usrdata (abfd) = gdata;
 
   bfd_alloc_data (abfd);
@@ -301,11 +324,11 @@ gdb_bfd_unref (struct bfd *abfd)
     return;
 
   archive_bfd = gdata->archive_bfd;
-  search.filename = bfd_get_filename (abfd);
+  search.canonical_filename = gdata->canonical_filename;
 
-  if (gdb_bfd_cache && search.filename)
+  if (gdb_bfd_cache && search.canonical_filename)
     {
-      hashval_t hash = htab_hash_string (search.filename);
+      hashval_t hash = htab_hash_string (search.canonical_filename);
       void **slot;
 
       search.mtime = gdata->mtime;