> Longer-term, if someone can tell me exactly what directives I should
 > use to emit ELF `.gnu.warning' sections with gcc 2.7.1 and binutils
 > 2.6, that'd be *greatly* appreciated.

I've researched this a bit (and asked on the gas mailing list for
some guidance), and found that this is what you need:

In gcc's config/mips/netbsd.h include the following code, taken
from elf64.h in the same directory:

/*
 A C statement to output something to the assembler file to switch to section
 NAME for object DECL which is either a FUNCTION_DECL, a VAR_DECL or
 NULL_TREE.  Some target formats do not support arbitrary sections.  Do not
 define this macro in such cases.
*/
#define ASM_OUTPUT_SECTION_NAME(F, DECL, NAME)                               \
do {                                                                         \
  extern FILE *asm_out_text_file;                                            \
  if ((DECL) && TREE_CODE (DECL) == FUNCTION_DECL)                           \
    fprintf (asm_out_text_file, "\t.section %s,\"ax\",@progbits\n", (NAME)); \
  else if ((DECL) && TREE_READONLY (DECL))                                   \
    fprintf (F, "\t.section %s,\"a\",@progbits\n", (NAME));                  \
  else                                                                       \
    fprintf (F, "\t.section %s,\"aw\",@progbits\n", (NAME));                 \
} while (0)

Recompile gcc and you can use this in the machine-specific cdefs.h:

#define __warn_references(symbol, msg)                  \
  static const char __evoke_link_warning_##symbol[]     \
    __attribute__ ((section (".gnu.warning." #symbol))) = msg;

This works OK with the NetBSD libraries, at least.  Some testing found
an obscure bug in the linker (if symbol isn't used at all, but there's
a .gnu.warning.symbol section), which you probably won't trigger, but
here's the patch I got from Ian Lance Taylor anyway:

diff -u -r1.21 elflink.h
--- elflink.h	1995/12/01 19:47:51	1.21
+++ elflink.h	1995/12/04 16:14:12
@@ -2508,6 +2508,12 @@
 
     case bfd_link_hash_indirect:
     case bfd_link_hash_warning:
+      /* We can't represent these symbols in ELF.  A warning symbol
+         may have come from a .gnu.warning.SYMBOL section anyhow.  We
+         just put the target symbol in the hash table.  If the target
+         symbol does not really exist, don't do anything.  */
+      if (h->root.u.i.link->type == bfd_link_hash_new)
+	return true;
       return (elf_link_output_extsym
 	      ((struct elf_link_hash_entry *) h->root.u.i.link, data));
     }


By the way, have you seen that I managed to prod a couple
of the other guys here to write sigsetjmp for us?  Submitted as
PR 1793, so you may have not seen it.  I'll include it here in
case anyone needs these functions.

  -  Arne H. J.


 > Message-Id: <199511270007.BAA18911@rype.runit.sintef.no>
 > Date: Mon, 27 Nov 1995 01:07:53 +0100
 > From: Havard.Eidnes@runit.sintef.no
 > Subject: lib/1793: pmax port lacks sigsetjmp / siglongjmp


>Number:         1793
>Category:       lib
>Synopsis:       pmax port lacks sigsetjmp / siglongjmp
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    lib-bug-people (Library Bug People)
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Sun Nov 26 19:35:01 1995
>Last-Modified:
>Originator:     Havard Eidnes
>Organization:
	SINTEF RUNIT
>Release:        1.1_ALPHA
>Environment:
	PMAX (any MIPS), NetBSD 1.1_Alpha, PMAX

>Description:
	pmax port lacks sigsetjmp / siglongjmp
>How-To-Repeat:
	inspect /usr/src/lib/libc/arch/mips/gen, no sigsetjmp.S
>Fix:

Insert this file as indicated above, modify Makefile.inc accordingly.

/*-
 * Copyright (c) 1991, 1993, 1995,
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Havard Eidnes.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/syscall.h>
#include <machine/reg.h>
#include <machine/machAsmDefs.h>
#include <machine/setjmp.h>

#if defined(LIBC_SCCS) && !defined(lint)
	ASMSTR("from: @(#)setjmp.s	8.1 (Berkeley) 6/4/93")
	ASMSTR("$Id: sigsetjmp.S,v 1.1 1994/12/15 17:24:51 he Exp $")
#endif /* LIBC_SCCS and not lint */

/*
 * C library -- sigsetjmp, siglongjmp
 *
 *	siglongjmp(a,v)
 * will generate a "return(v)" from
 * the last call to
 *	sigsetjmp(a, savemask)
 * by restoring registers from the stack,
 * and dependent on savemask restores the
 * signal mask.
 */

LEAF(sigsetjmp)
	sw	a1, (_JBLEN*4)(a0)		# save "savemask"
	bne	a1, 0x0, 1f			# do saving of signal mask?
	j	_setjmp
1:	j	setjmp
END(sigsetjmp)

LEAF(siglongjmp)
	lw	t0, (_JBLEN * 4)(a0)		# get "savemask"
	bne	t0, 0x0, 1f			# restore signal mask?
	j	_longjmp
1:	j	longjmp
END(siglongjmp)
>Audit-Trail:
>Unformatted: