bfd_get_size cache

We have calls to bfd_get_size when swapping in ELF section headers.
Since object files can have a large number of sections, it's worth
caching the file size rather than making lots of stat system calls.

	* bfd.c (struct bfd): Move format and direction to other
	bitfields.  Add "size".
	* bfdio.c (bfd_get_size): Cache size when not writing file.
	* opncls.c (bfd_get_debug_link_info_1): Allow for bfd_get_size
	returning zero, ie. unknown.
	(bfd_get_alt_debug_link_info): Likewise.
	* bfd-in2.h: Regenerate.

1 files changed, 19 insertions, 4 deletions

diff --git a/bfd/bfdio.c b/bfd/bfdio.c
index fd81b93..49e0958 100644
--- a/bfd/bfdio.c
+++ b/bfd/bfdio.c
@@ -415,17 +415,32 @@ DESCRIPTION
 	of space for the 15 bazillon byte table it is about to read.
 	This function at least allows us to answer the question, "is the
 	size reasonable?".
+
+	A return value of zero indicates the file size is unknown.
 */
 
 ufile_ptr
 bfd_get_size (bfd *abfd)
 {
-  struct stat buf;
+  /* A size of 0 means we haven't yet called bfd_stat.  A size of 1
+     means we have a cached value of 0, ie. unknown.  */
+  if (abfd->size <= 1 || bfd_write_p (abfd))
+    {
+      struct stat buf;
 
-  if (bfd_stat (abfd, &buf) != 0)
-    return 0;
+      if (abfd->size == 1 && !bfd_write_p (abfd))
+	return 0;
 
-  return buf.st_size;
+      if (bfd_stat (abfd, &buf) != 0
+	  || buf.st_size == 0
+	  || buf.st_size - (ufile_ptr) buf.st_size != 0)
+	{
+	  abfd->size = 1;
+	  return 0;
+	}
+      abfd->size = buf.st_size;
+    }
+  return abfd->size;
 }
 
 /*