commit eeeaf705fe1c94e9330fa222d7928a9d0f03832a
author Alan Modra <amodra@gmail.com> Mon Jul 04 12:45:47 2022 +0930
committer Alan Modra <amodra@gmail.com> Mon Jul 04 22:51:56 2022 +0930
tree edbba8cbb9a0deedb2dda7a037511c9ef2031d1b
parent 0772daccb3ebaf513badf4266e1948454b4455c1

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.

gas/as.h

diff --git a/gas/as.h b/gas/as.h
index 470a2e5..ec0c12a 100644
--- a/gas/as.h
+++ b/gas/as.h
@@ -476,6 +476,7 @@
 void   new_logical_line (const char *, int);
 void   new_logical_line_flags (const char *, int, int);
 void   subsegs_begin (void);
+void   subsegs_end (struct obstack **);
 void   subseg_change (segT, int);
 segT   subseg_new (const char *, subsegT);
 segT   subseg_force_new (const char *, subsegT);

gas/output-file.c

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 @@
     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 ()));

gas/subsegs.c

diff --git a/gas/subsegs.c b/gas/subsegs.c
index cb598e8..1776511 100644
--- a/gas/subsegs.c
+++ b/gas/subsegs.c
@@ -43,7 +43,27 @@
   frchain_now = NULL;		/* Warn new_subseg() that we are booting.  */
   frag_now = &dummy_frag;
 }
+
+void
+subsegs_end (struct obstack **obs)
+{
+  for (; *obs; obs++)
+    _obstack_free (*obs, NULL);
+  _obstack_free (&frchains, NULL);
+  _obstack_free (&cond_obstack, NULL);
+  _obstack_free (&notes, NULL);
+}
 
+static void
+alloc_seginfo (segT seg)
+{
+  segment_info_type *seginfo;
+
+  seginfo = obstack_alloc (&notes, sizeof (*seginfo));
+  memset (seginfo, 0, sizeof (*seginfo));
+  seginfo->bfd_section = seg;
+  bfd_set_section_userdata (seg, seginfo);
+}
 /*
  *			subseg_change()
  *
@@ -57,16 +77,11 @@
 void
 subseg_change (segT seg, int subseg)
 {
-  segment_info_type *seginfo = seg_info (seg);
   now_seg = seg;
   now_subseg = subseg;
 
-  if (! seginfo)
-    {
-      seginfo = XCNEW (segment_info_type);
-      seginfo->bfd_section = seg;
-      bfd_set_section_userdata (seg, seginfo);
-    }
+  if (!seg_info (seg))
+    alloc_seginfo (seg);
 }
 
 static void
@@ -149,7 +164,6 @@
 subseg_get (const char *segname, int force_new)
 {
   segT secptr;
-  segment_info_type *seginfo;
   const char *now_seg_name = now_seg ? bfd_section_name (now_seg) : 0;
 
   if (!force_new
@@ -163,13 +177,10 @@
   else
     secptr = bfd_make_section_anyway (stdoutput, segname);
 
-  seginfo = seg_info (secptr);
-  if (! seginfo)
+  if (!seg_info (secptr))
     {
       secptr->output_section = secptr;
-      seginfo = XCNEW (segment_info_type);
-      seginfo->bfd_section = secptr;
-      bfd_set_section_userdata (secptr, seginfo);
+      alloc_seginfo (secptr);
     }
   return secptr;
 }