Re: [PATCH] Make obj_sec_set_private_data into a format_ops member

[Alan Modra <amodra@bigpond.net.au>]

On Tue, May 02, 2006 at 11:19:35AM +0100, Dave Korn wrote:
> objects.  It's certainly not necessary to call the hook for those other
> formats, and indeed is not just superfluous but can also be actually
> incorrect; for instance it leads to a null pointer dereference on cygwin.

How?

>   My patch preserves existing behaviour in non-multi-obj, fixes incorrect

Yeah, I know.  Your patch is good, but I'm going to rip out
obj_sec_set_private_data completely.  Here's a preview.  I haven't
finished a regression test yet, so things might need to change.
Especially if I run into your NULL deref.

Index: bfd/section.c
===================================================================
RCS file: /cvs/src/src/bfd/section.c,v
retrieving revision 1.91
diff -u -p -r1.91 section.c
--- bfd/section.c	16 Mar 2006 12:20:16 -0000	1.91
+++ bfd/section.c	2 May 2006 06:58:14 -0000
@@ -964,7 +964,6 @@ DESCRIPTION
 asection *
 bfd_make_section_old_way (bfd *abfd, const char *name)
 {
-  struct section_hash_entry *sh;
   asection *newsect;
 
   if (abfd->output_has_begun)
@@ -974,30 +973,37 @@ bfd_make_section_old_way (bfd *abfd, con
     }
 
   if (strcmp (name, BFD_ABS_SECTION_NAME) == 0)
-    return bfd_abs_section_ptr;
-
-  if (strcmp (name, BFD_COM_SECTION_NAME) == 0)
-    return bfd_com_section_ptr;
-
-  if (strcmp (name, BFD_UND_SECTION_NAME) == 0)
-    return bfd_und_section_ptr;
-
-  if (strcmp (name, BFD_IND_SECTION_NAME) == 0)
-    return bfd_ind_section_ptr;
+    newsect = bfd_abs_section_ptr;
+  else if (strcmp (name, BFD_COM_SECTION_NAME) == 0)
+    newsect = bfd_com_section_ptr;
+  else if (strcmp (name, BFD_UND_SECTION_NAME) == 0)
+    newsect = bfd_und_section_ptr;
+  else if (strcmp (name, BFD_IND_SECTION_NAME) == 0)
+    newsect = bfd_ind_section_ptr;
+  else
+    {
+      struct section_hash_entry *sh;
 
-  sh = section_hash_lookup (&abfd->section_htab, name, TRUE, FALSE);
-  if (sh == NULL)
-    return NULL;
+      sh = section_hash_lookup (&abfd->section_htab, name, TRUE, FALSE);
+      if (sh == NULL)
+	return NULL;
 
-  newsect = &sh->section;
-  if (newsect->name != NULL)
-    {
-      /* Section already exists.  */
-      return newsect;
+      newsect = &sh->section;
+      if (newsect->name != NULL)
+	{
+	  /* Section already exists.  */
+	  return newsect;
+	}
+
+      newsect->name = name;
+      return bfd_section_init (abfd, newsect);
     }
 
-  newsect->name = name;
-  return bfd_section_init (abfd, newsect);
+  /* Call new_section_hook when "creating" the standard abs, com, und
+     and ind sections to tack on format specific section data.  */
+  if (! BFD_SEND (abfd, _new_section_hook, (abfd, newsect)))
+    return NULL;
+  return newsect;
 }
 
 /*
Index: gas/config/obj-elf.h
===================================================================
RCS file: /cvs/src/src/gas/config/obj-elf.h,v
retrieving revision 1.28
diff -u -p -r1.28 obj-elf.h
--- gas/config/obj-elf.h	20 Sep 2005 18:24:45 -0000	1.28
+++ gas/config/obj-elf.h	2 May 2006 06:58:20 -0000
@@ -134,13 +134,6 @@ int elf_s_get_other (symbolS *);
 
 extern asection *gdb_section;
 
-#ifndef obj_sec_set_private_data
-#define obj_sec_set_private_data(B, S) \
-  if (! BFD_SEND ((B), _new_section_hook, ((B), (S)))) \
-    as_fatal (_("can't allocate ELF private section data: %s"),	\
-	      bfd_errmsg (bfd_get_error ()))
-#endif
-
 #ifndef obj_frob_file
 #define obj_frob_file  elf_frob_file
 #endif
Index: gas/subsegs.c
===================================================================
RCS file: /cvs/src/src/gas/subsegs.c,v
retrieving revision 1.28
diff -u -p -r1.28 subsegs.c
--- gas/subsegs.c	1 May 2006 05:41:40 -0000	1.28
+++ gas/subsegs.c	2 May 2006 06:58:18 -0000
@@ -244,10 +174,6 @@ subseg_get (const char *segname, int for
   else
     secptr = bfd_make_section_anyway (stdoutput, segname);
 
-#ifdef obj_sec_set_private_data
-  obj_sec_set_private_data (stdoutput, secptr);
-#endif
-
   seginfo = seg_info (secptr);
   if (! seginfo)
     {


-- 
Alan Modra
IBM OzLabs - Linux Technology Centre