alloc gas seginfo on notes obstack

Lots of memory used in gas should go on this obstack.  The patch also
frees all the gas obstacks on exit, which isn't a completely trivial
task.

	* subsegs.c (alloc_seginfo): New function.
	(subseg_change, subseg_get): Use it.
	(subsegs_end): New function.
	* as.h (subsegs_end): Declare.
	* output-file.c: Include subsegs.h
	(stash_frchain_obs): New function.
	(output_file_close): Save obstacks attached to output bfd before
	closing.  Call subsegs_end with the array of obstacks.

1 files changed, 37 insertions, 5 deletions

diff --git a/gas/output-file.c b/gas/output-file.c
index 9852a2e..95e21d2 100644
--- a/gas/output-file.c
+++ b/gas/output-file.c
@@ -19,6 +19,7 @@
    02110-1301, USA.  */
 
 #include "as.h"
+#include "subsegs.h"
 #include "output-file.h"
 
 #ifndef TARGET_MACH
@@ -49,23 +50,54 @@ output_file_create (const char *name)
     stdoutput->flags |= BFD_TRADITIONAL_FORMAT;
 }
 
+static void
+stash_frchain_obs (asection *sec)
+{
+  segment_info_type *info = seg_info (sec);
+  if (info)
+    {
+      struct frchain *frchp;
+      for (frchp = info->frchainP; frchp; frchp = frchp->frch_next)
+	obstack_ptr_grow (&notes, &frchp->frch_obstack);
+      info->frchainP = NULL;
+    }
+}
+
 void
 output_file_close (const char *filename)
 {
   bool res;
+  bfd *obfd = stdoutput;
+  struct obstack **obs;
+  asection *sec;
 
-  if (stdoutput == NULL)
+  if (obfd == NULL)
     return;
 
+  /* Prevent an infinite loop - if the close failed we will call as_fatal
+     which will call xexit() which may call this function again...  */
+  stdoutput = NULL;
+
+  /* We can't free obstacks attached to the output bfd sections before
+     closing the output bfd since data in those obstacks may need to
+     be accessed, but we can't access anything in the output bfd after
+     it is closed..  */
+  for (sec = obfd->sections; sec; sec = sec->next)
+    stash_frchain_obs (sec);
+  stash_frchain_obs (reg_section);
+  stash_frchain_obs (expr_section);
+  stash_frchain_obs (bfd_abs_section_ptr);
+  stash_frchain_obs (bfd_und_section_ptr);
+  obstack_ptr_grow (&notes, NULL);
+  obs = obstack_finish (&notes);
+
   /* Close the bfd.  */
   if (!flag_always_generate_output && had_errors ())
     res = bfd_cache_close_all ();
   else
-    res = bfd_close (stdoutput);
+    res = bfd_close (obfd);
 
-  /* Prevent an infinite loop - if the close failed we will call as_fatal
-     which will call xexit() which may call this function again...  */
-  stdoutput = NULL;
+  subsegs_end (obs);
 
   if (! res)
     as_fatal ("%s: %s", filename, bfd_errmsg (bfd_get_error ()));