[Bug c/60797] New: gcc hangs with error: only weak aliases are supported in this configuration

[Bug c/60797] New: gcc hangs with error: only weak aliases are supported in this configuration

[junchao.zhang at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60797

            Bug ID: 60797
           Summary: gcc hangs with error: only weak aliases are supported
                    in this configuration
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: junchao.zhang at gmail dot com

On my Mac OS X 10.9.2, when I use gcc to compile this program, test.c,

#include <stdio.h>

extern int foo __attribute__((alias("bar")));
int main()
{
    return 0;
}

gcc hangs with countless 
test.c:3:12: error: only weak aliases are supported in this configuration
test.c:3:12: error: only weak aliases are supported in this configuration
test.c:3:12: error: only weak aliases are supported in this configuration
...

[Bug c/60797] gcc hangs with error: only weak aliases are supported in this configuration

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60797

Dominique d'Humieres <dominiq at lps dot ens.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-04-09
     Ever confirmed|0                           |1

--- Comment #1 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
r206658 gives

pr60797.c:3:12: error: only weak aliases are supported in this configuration
 extern int foo __attribute__((alias("bar")));
            ^
pr60797.c:3:12: error: only weak aliases are supported in this configuration

while r206880 gives the "infinite" errors.

[Bug middle-end/60797] [4.9 Regression] gcc hangs with error: only weak aliases are supported in this configuration

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60797

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |x86_64-*-darwin
                 CC|                            |hubicka at gcc dot gnu.org
   Target Milestone|---                         |4.9.0
            Summary|gcc hangs with error: only  |[4.9 Regression] gcc hangs
                   |weak aliases are supported  |with error: only weak
                   |in this configuration       |aliases are supported in
                   |                            |this configuration

[Bug middle-end/60797] [4.9 Regression] gcc hangs with error: only weak aliases are supported in this configuration

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60797

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
0x0000000000615b12 in c_write_global_declarations_1 (
    globals=<type_decl 0x7ffff6c4d170 int>)
    at /space/rguenther/src/svn/trunk/gcc/c/c-decl.c:10276
10272     do
10273       {
10274         reconsider = false;
10275         for (decl = globals; decl; decl = DECL_CHAIN (decl))
10276           reconsider |= wrapup_global_declaration_2 (decl);
10277       }
10278     while (reconsider);

which basically endlessly loops because nothing sets TREE_ASM_WRITTEN on
the alias.

Index: gcc/varasm.c
===================================================================
--- gcc/varasm.c        (revision 209292)
+++ gcc/varasm.c        (working copy)
@@ -5675,6 +5675,7 @@ assemble_alias (tree decl, tree target)
          else
            error_at (DECL_SOURCE_LOCATION (decl),
                      "only weak aliases are supported in this configuration");
+         TREE_ASM_WRITTEN (decl) = 1;
          return;
        }
 # endif

fixes it.  Probably also needed above for targets without any alias support.
I wonder why "weakref" errors just fall through and don't return though.

Index: gcc/varasm.c
===================================================================
--- gcc/varasm.c        (revision 209292)
+++ gcc/varasm.c        (working copy)
@@ -5665,6 +5665,7 @@ assemble_alias (tree decl, tree target)
 # if !defined(ASM_OUTPUT_WEAK_ALIAS) && !defined (ASM_WEAKEN_DECL)
       error_at (DECL_SOURCE_LOCATION (decl),
                "alias definitions not supported in this configuration");
+      TREE_ASM_WRITTEN (decl) = 1;
       return;
 # else
       if (!DECL_WEAK (decl))
@@ -5675,6 +5676,7 @@ assemble_alias (tree decl, tree target)
          else
            error_at (DECL_SOURCE_LOCATION (decl),
                      "only weak aliases are supported in this configuration");
+         TREE_ASM_WRITTEN (decl) = 1;
          return;
        }
 # endif

[Bug middle-end/60797] [4.9 Regression] gcc hangs with error: only weak aliases are supported in this configuration

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60797

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Testcase:

/* { dg-do compile } */
/* { dg-skip-if "" { alias } } */

extern int foo __attribute__((alias("bar"))); /* { dg-error "supported" } */
int main()
{
  return 0;
}

[Bug middle-end/60797] [4.9 Regression] gcc hangs with error: only weak aliases are supported in this configuration

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60797

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.

[Bug middle-end/60797] [4.9 Regression] gcc hangs with error: only weak aliases are supported in this configuration

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60797

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Fri Apr 11 11:45:44 2014
New Revision: 209299

URL: http://gcc.gnu.org/viewcvs?rev=209299&root=gcc&view=rev
Log:
2014-04-11  Richard Biener  <rguenther@suse.de>

    PR middle-end/60797
    * varasm.c (assemble_alias): Avoid endless error reporting
    recursion by setting TREE_ASM_WRITTEN.

    * gcc.dg/pr60797.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/pr60797.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/varasm.c