Re: `typeinfo for foo' referenced in section `.text' of bar.o: defined in discarded section `.gnu.linkonce.d._ZTI4foo' of r2.o

[Alan Modra <amodra at bigpond dot net dot au>]

This is the other part of the mainline fix for PR 568.  Mainline
currently bombs immediately if we get references to symbols in discarded
sections, which is a little harsh considering that people might be using
older compilers with a new binutils.  Also, there are situations where
even a new gcc will hit this linker error, for example
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17828 so we ought to at
least give people a chance to continue past this error.  I've made that
possible by printing the error via a new linker callback, which flags
the output as invalid and normally not written.  It's possible to
override this behaviour with --noinhibit-exec.  Lots of other places in
bfd linker functions probably should use this rather than calling
bfd_error_handler and giving up.

include/
	* bfdlink.h (struct bfd_link_callbacks): Add einfo.
bfd/
	* configure.in: Bump version
	* configure: Regenerate.
	* elflink.c (elf_link_input_bfd): Use einfo linker callback to print
	discarded section sym refs and kill linker output.
	* simple.c (simple_dummy_einfo): New function.
	(bfd_simple_get_relocated_section_contents): Init callbacks.einfo.
ld/
	* ldmain.c (link_callbacks): Add einfo.
	(add_archive_element): Use passed info, not link_info.
	(constructor_callback): Likewise.
	(reloc_overflow): Don't handle null bfd specially.
	(reloc_dangerous, unattached_reloc): Likewise.
	* ldmisc.c (vfinfo <B>): Print "ld generated" for null bfd.
	(vfinfo <C, D, G>): Handle null bfd.  Wrap comments.

Index: include/bfdlink.h
===================================================================
RCS file: /cvs/src/src/include/bfdlink.h,v
retrieving revision 1.55
diff -u -p -r1.55 bfdlink.h
--- include/bfdlink.h	10 May 2005 10:21:08 -0000	1.55
+++ include/bfdlink.h	3 Jun 2005 06:40:56 -0000
@@ -422,11 +422,11 @@ struct bfd_link_info
 };
 
 /* This structures holds a set of callback functions.  These are
-   called by the BFD linker routines.  The first argument to each
-   callback function is the bfd_link_info structure being used.  Each
-   function returns a boolean value.  If the function returns FALSE,
-   then the BFD function which called it will return with a failure
-   indication.  */
+   called by the BFD linker routines.  Except for einfo, the first
+   argument to each callback function is the bfd_link_info structure
+   being used and each function returns a boolean value.  If the
+   function returns FALSE, then the BFD function which called it should
+   return with a failure indication.  */
 
 struct bfd_link_callbacks
 {
@@ -535,6 +535,9 @@ struct bfd_link_callbacks
   bfd_boolean (*notice)
     (struct bfd_link_info *, const char *name,
      bfd *abfd, asection *section, bfd_vma address);
+  /* General link info message.  */
+  void (*einfo)
+    (const char *fmt, ...);
 };
 
 /* The linker builds link_order structures which tell the code how to
Index: bfd/configure.in
===================================================================
RCS file: /cvs/src/src/bfd/configure.in,v
retrieving revision 1.185
diff -u -p -r1.185 configure.in
--- bfd/configure.in	29 May 2005 23:13:39 -0000	1.185
+++ bfd/configure.in	3 Jun 2005 09:33:50 -0000
@@ -8,7 +8,7 @@ AC_CONFIG_SRCDIR([libbfd.c])
 AC_CANONICAL_TARGET
 AC_ISC_POSIX
 
-AM_INIT_AUTOMAKE(bfd, 2.16.90)
+AM_INIT_AUTOMAKE(bfd, 2.16.91)
 
 dnl These must be called before AM_PROG_LIBTOOL, because it may want
 dnl to call AC_CHECK_PROG.
Index: bfd/elflink.c
===================================================================
RCS file: /cvs/src/src/bfd/elflink.c,v
retrieving revision 1.165
diff -u -p -r1.165 elflink.c
--- bfd/elflink.c	19 May 2005 08:26:55 -0000	1.165
+++ bfd/elflink.c	3 Jun 2005 06:40:14 -0000
@@ -7087,14 +7087,10 @@ elf_link_input_bfd (struct elf_final_lin
 		    {
 		      BFD_ASSERT (r_symndx != 0);
 		      if (action & COMPLAIN)
-			{
-			  (*_bfd_error_handler)
-			    (_("`%s' referenced in section `%A' of %B: "
-			       "defined in discarded section `%A' of %B"),
-			     o, input_bfd, sec, sec->owner, sym_name);
-			  bfd_set_error (bfd_error_bad_value);
-			  return FALSE;
-			}
+			(*finfo->info->callbacks->einfo)
+			  (_("%X`%s' referenced in section `%A' of %B: "
+			     "defined in discarded section `%A' of %B"),
+			   sym_name, o, input_bfd, sec, sec->owner);
 
 		      /* Try to do the best we can to support buggy old
 			 versions of gcc.  If we've warned, or this is
Index: bfd/simple.c
===================================================================
RCS file: /cvs/src/src/bfd/simple.c,v
retrieving revision 1.24
diff -u -p -r1.24 simple.c
--- bfd/simple.c	4 May 2005 15:53:38 -0000	1.24
+++ bfd/simple.c	3 Jun 2005 06:40:15 -0000
@@ -92,6 +92,11 @@ simple_dummy_multiple_definition (struct
   return TRUE;
 }
 
+static void
+simple_dummy_einfo (const char *fmt ATTRIBUTE_UNUSED, ...)
+{
+}
+
 struct saved_output_info
 {
   bfd_vma offset;
@@ -187,6 +192,7 @@ bfd_simple_get_relocated_section_content
   callbacks.reloc_dangerous = simple_dummy_reloc_dangerous;
   callbacks.unattached_reloc = simple_dummy_unattached_reloc;
   callbacks.multiple_definition = simple_dummy_multiple_definition;
+  callbacks.einfo = simple_dummy_einfo;
 
   memset (&link_order, 0, sizeof (link_order));
   link_order.next = NULL;
Index: ld/ldmain.c
===================================================================
RCS file: /cvs/src/src/ld/ldmain.c,v
retrieving revision 1.97
diff -u -p -r1.97 ldmain.c
--- ld/ldmain.c	12 May 2005 07:32:03 -0000	1.97
+++ ld/ldmain.c	3 Jun 2005 06:41:06 -0000
@@ -160,7 +160,8 @@ static struct bfd_link_callbacks link_ca
   reloc_overflow,
   reloc_dangerous,
   unattached_reloc,
-  notice
+  notice,
+  einfo
 };
 
 struct bfd_link_info link_info;
@@ -873,7 +874,7 @@ add_keepsyms_file (const char *filename)
    a link.  */
 
 static bfd_boolean
-add_archive_element (struct bfd_link_info *info ATTRIBUTE_UNUSED,
+add_archive_element (struct bfd_link_info *info,
 		     bfd *abfd,
 		     const char *name)
 {
@@ -904,7 +905,7 @@ add_archive_element (struct bfd_link_inf
       bfd *from;
       int len;
 
-      h = bfd_link_hash_lookup (link_info.hash, name, FALSE, FALSE, TRUE);
+      h = bfd_link_hash_lookup (info->hash, name, FALSE, FALSE, TRUE);
 
       if (h == NULL)
 	from = NULL;
@@ -1145,7 +1146,7 @@ constructor_callback (struct bfd_link_in
   /* Ensure that BFD_RELOC_CTOR exists now, so that we can give a
      useful error message.  */
   if (bfd_reloc_type_lookup (output_bfd, BFD_RELOC_CTOR) == NULL
-      && (link_info.relocatable
+      && (info->relocatable
 	  || bfd_reloc_type_lookup (abfd, BFD_RELOC_CTOR) == NULL))
     einfo (_("%P%F: BFD backend error: BFD_RELOC_CTOR unsupported\n"));
 
@@ -1422,10 +1423,7 @@ reloc_overflow (struct bfd_link_info *in
   if (overflow_cutoff_limit == -1)
     return TRUE;
 
-  if (abfd == NULL)
-    einfo (_("%P%X: generated"));
-  else
-    einfo ("%X%C:", abfd, section, address);
+  einfo ("%X%C:", abfd, section, address);
 
   if (overflow_cutoff_limit >= 0
       && overflow_cutoff_limit-- == 0)
@@ -1477,11 +1475,8 @@ reloc_dangerous (struct bfd_link_info *i
 		 asection *section,
 		 bfd_vma address)
 {
-  if (abfd == NULL)
-    einfo (_("%P%X: generated"));
-  else
-    einfo ("%X%C:", abfd, section, address);
-  einfo (_("dangerous relocation: %s\n"), message);
+  einfo (_("%X%C: dangerous relocation: %s\n"),
+	 abfd, section, address, message);
   return TRUE;
 }
 
@@ -1495,11 +1490,8 @@ unattached_reloc (struct bfd_link_info *
 		  asection *section,
 		  bfd_vma address)
 {
-  if (abfd == NULL)
-    einfo (_("%P%X: generated"));
-  else
-    einfo ("%X%C:", abfd, section, address);
-  einfo (_(" reloc refers to symbol `%T' which is not being output\n"), name);
+  einfo (_("%X%C: reloc refers to symbol `%T' which is not being output\n"),
+	 abfd, section, address, name);
   return TRUE;
 }
 
Index: ld/ldmisc.c
===================================================================
RCS file: /cvs/src/src/ld/ldmisc.c,v
retrieving revision 1.25
diff -u -p -r1.25 ldmisc.c
--- ld/ldmisc.c	12 May 2005 07:32:03 -0000	1.25
+++ ld/ldmisc.c	3 Jun 2005 06:41:06 -0000
@@ -190,7 +190,7 @@ vfinfo (FILE *fp, const char *fmt, va_li
 		bfd *abfd = va_arg (arg, bfd *);
 
 		if (abfd == NULL)
-		  fprintf (fp, "<none>");
+		  fprintf (fp, "%s generated", program_name);
 		else if (abfd->my_archive)
 		  fprintf (fp, "%s(%s)", abfd->my_archive->filename,
 			   abfd->filename);
@@ -275,49 +275,62 @@ vfinfo (FILE *fp, const char *fmt, va_li
 		section = va_arg (arg, asection *);
 		offset = va_arg (arg, bfd_vma);
 
-		entry = (lang_input_statement_type *) abfd->usrdata;
-		if (entry != (lang_input_statement_type *) NULL
-		    && entry->asymbols != (asymbol **) NULL)
-		  asymbols = entry->asymbols;
+		if (abfd == NULL)
+		  {
+		    entry = NULL;
+		    asymbols = NULL;
+		  }
 		else
 		  {
-		    long symsize;
-		    long symbol_count;
-
-		    symsize = bfd_get_symtab_upper_bound (abfd);
-		    if (symsize < 0)
-		      einfo (_("%B%F: could not read symbols\n"), abfd);
-		    asymbols = xmalloc (symsize);
-		    symbol_count = bfd_canonicalize_symtab (abfd, asymbols);
-		    if (symbol_count < 0)
-		      einfo (_("%B%F: could not read symbols\n"), abfd);
-		    if (entry != (lang_input_statement_type *) NULL)
+		    entry = (lang_input_statement_type *) abfd->usrdata;
+		    if (entry != (lang_input_statement_type *) NULL
+			&& entry->asymbols != (asymbol **) NULL)
+		      asymbols = entry->asymbols;
+		    else
 		      {
-			entry->asymbols = asymbols;
-			entry->symbol_count = symbol_count;
+			long symsize;
+			long sym_count;
+
+			symsize = bfd_get_symtab_upper_bound (abfd);
+			if (symsize < 0)
+			  einfo (_("%B%F: could not read symbols\n"), abfd);
+			asymbols = xmalloc (symsize);
+			sym_count = bfd_canonicalize_symtab (abfd, asymbols);
+			if (sym_count < 0)
+			  einfo (_("%B%F: could not read symbols\n"), abfd);
+			if (entry != (lang_input_statement_type *) NULL)
+			  {
+			    entry->asymbols = asymbols;
+			    entry->symbol_count = sym_count;
+			  }
 		      }
 		  }
 
-		/* The GNU Coding Standard requires that error messages be of the form:
+		/* The GNU Coding Standard requires that error messages
+		   be of the form:
 		   
 		     source-file-name:lineno: message
 
-		   We do not always have a line number available so if we cannot find
-		   them we print out the section name and offset instread.  */
+		   We do not always have a line number available so if
+		   we cannot find them we print out the section name and
+		   offset instread.  */
 		discard_last = TRUE;
-		if (bfd_find_nearest_line (abfd, section, asymbols, offset,
-					   &filename, &functionname,
-					   &linenumber))
+		if (abfd != NULL
+		    && bfd_find_nearest_line (abfd, section, asymbols, offset,
+					      &filename, &functionname,
+					      &linenumber))
 		  {
 		    if (functionname != NULL && fmt[-1] == 'C')
 		      {
-			/* Detect the case where we are printing out a message
-			   for the same function as the last call to vinfo ("%C").
-			   In this situation do not print out the ABFD filename
-			   or the function name again.  Note - we do still print
-			   out the source filename, as this will allow programs
-			   that parse the linker's output (eg emacs) to correctly
-			   locate multiple errors in the same source file.  */
+			/* Detect the case where we are printing out a
+			   message for the same function as the last
+			   call to vinfo ("%C").  In this situation do
+			   not print out the ABFD filename or the
+			   function name again.  Note - we do still
+			   print out the source filename, as this will
+			   allow programs that parse the linker's output
+			   (eg emacs) to correctly locate multiple
+			   errors in the same source file.  */
 			if (last_bfd == NULL
 			    || last_file == NULL
 			    || last_function == NULL

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre