[Bug bootstrap/26053] New: Misdetection of COMDAT group support with GNU as and non-GNU ld

[Bug bootstrap/26053] New: Misdetection of COMDAT group support with GNU as and non-GNU ld

[gcc-bugzilla at gcc dot gnu dot org]

When configuring the 4.1 branch (I haven't tried this on mainline yet since
I only recently found a workaround for PR target/24334) on IRIX 6.5 with
GNU as 2.16.1 and the SGI MIPSpro ld, libstdc++.so fails to link:

ld32: FATAL   2  : Internal: at ../../ld/section_type.c In load_info() unknown
section type
collect2: ld returned 1 exit status
make[5]: *** [libstdc++.la] Error 1

While the error message could be clearer ;-), this is obviously due to e.g.

allocator-inst.o:

          **** SECTION  HEADER  TABLE ****
[No]   Type                  Addr       Offset     Size        Name
       Link       Info       Adralgn    Entsize    Flags

[1]    0x11                  0          0x34       0x8         .group
       43         0x25       0x4        0x4        0x00000000 


(excerpt of elfdump -h output): Section Type 0x11 (obviously unknown to
elfdump) is SHT_GROUP.  While the version of GNU as used obviously supports
COMDAT group, the native ld does not.

It turns out that the test in gcc/configure.ac for COMDAT group support is
wrong if using GNU as with a non-GNU ld:

if test $in_tree_ld != yes && test x"$ld_vers" != x; then
  comdat_group=yes
  if test 0"$ld_date" -lt 20050308; then
    if test -n "$ld_date"; then
      # If there was date string, but was earlier than 2005-03-08, fail
      comdat_group=no
    elif test "$ld_vers_major" -lt 2; then
      comdat_group=no
    elif test "$ld_vers_major" -eq 2 -a "$ld_vers_minor" -lt 16; then
      comdat_group=no
    fi
  fi
  if test $comdat_group = no; then
    gcc_cv_as_comdat_group=no
    gcc_cv_as_comdat_group_percent=no
  fi
fi

For non-in_tree_ld and non-GNU ld (i.e. $ld_vers empty), only
gcc_cv_as_comdat_group* results from above this section are used, but
instead for non-GNU ld, no COMDAT group support should be assumed.

It may be that e.g. the Solaris 10+ ld does support this, but we either
need a configure check for this or statically define this in configure.ac
if it is hard/impossible to check at configure time.

This triggers only with GNU as 2.16.1, since 2.15 on IRIX 6 SEGVs with
gas COMDAT group tests, thus GNU as isn't known to support COMDAT group in
2.15.

Environment:
System: IRIX sculptor 6.5 10060437 IP32



host: mips-sgi-irix6.5
build: mips-sgi-irix6.5
target: mips-sgi-irix6.5
configured with: /vol/gcc/src/gcc-4.1-branch-dist/configure --prefix=/vol/gcc
--with-local-prefix=/vol/gcc --disable-nls --with-gnu-as
--with-as=/vol/gcc/lib/gas-2.16.1 --enable-libgcj --disable-multilib
--with-gmp-dir=/vol/gnu/obj/gmp-4.1.3
--with-mpfr-dir=/vol/gnu/obj/gmp-4.1.3/mpfr
--enable-languages=c,c++,fortran,java,objc,ada

How-To-Repeat:
Bootstrap the 4.1 branch (mainline is almost certainly affected as well) as
described above.


------- Comment #1 from ro at techfak dot uni-bielefeld dot de  2006-01-31 22:29 -------
Fix:
The following patch allowed a bootstrap on the 4.1 branch to finish
successfully:

Index: gcc/configure.ac
===================================================================
--- gcc/configure.ac    (revision 110450)
+++ gcc/configure.ac    (working copy)
@@ -2175,10 +2175,13 @@ if test $in_tree_ld != yes && test x"$ld
       comdat_group=no
     fi
   fi
-  if test $comdat_group = no; then
-    gcc_cv_as_comdat_group=no
-    gcc_cv_as_comdat_group_percent=no
-  fi
+else
+  # assume linkers other than GNU ld don't support COMDAT group
+  comdat_group=no
+fi
+if test $comdat_group = no; then
+  gcc_cv_as_comdat_group=no
+  gcc_cv_as_comdat_group_percent=no
 fi
 AC_DEFINE_UNQUOTED(HAVE_COMDAT_GROUP,
   [`if test $gcc_cv_as_comdat_group = yes || test
$gcc_cv_as_comdat_group_percent = yes; then echo 1; else echo 0; fi`],

I need to test this on mainline and properly submit to gcc-patches.


-- 
           Summary: Misdetection of COMDAT group support with GNU as and
                    non-GNU ld
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ro at techfak dot uni-bielefeld dot de
 GCC build triplet: mips-sgi-irix6.5
  GCC host triplet: mips-sgi-irix6.5
GCC target triplet: mips-sgi-irix6.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26053

[Bug bootstrap/26053] [4.1/4.2 Regression] Misdetection of COMDAT group support with GNU as and non-GNU ld

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2006-01-31 22:42 -------
This is at least a 4.1/4.2 regression, I forgot when comdat support was added.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |build
            Summary|Misdetection of COMDAT group|[4.1/4.2 Regression]
                   |support with GNU as and non-|Misdetection of COMDAT group
                   |GNU ld                      |support with GNU as and non-
                   |                            |GNU ld
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26053

[Bug bootstrap/26053] [4.1/4.2 Regression] Misdetection of COMDAT group support with GNU as and non-GNU ld

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2006-02-01 01:38 -------
Confirmed.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-02-01 01:38:23
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26053

[Bug bootstrap/26053] [4.1/4.2 Regression] Misdetection of COMDAT group support with GNU as and non-GNU ld

[mmitchel at gcc dot gnu dot org]

------- Comment #4 from mmitchel at gcc dot gnu dot org  2006-02-01 03:26 -------
I agree that the configure test is broken.  

We could have a --enable-comdat option, or, as you say, we could have something
in the target configuration file.  I think your patch is the right idea, but I
do think we need a --enable-comdat option, if we go that route, so that we can
specifically indicate that a particular linker *does* support COMDAT.


-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26053

[Bug bootstrap/26053] [4.1/4.2 Regression] Misdetection of COMDAT group support with GNU as and non-GNU ld

[ro at techfak dot uni-bielefeld dot de]

------- Comment #5 from ro at techfak dot uni-bielefeld dot de  2006-02-02 12:32 -------
Subject: Re:  [4.1/4.2 Regression] Misdetection of COMDAT group support with
GNU as and non-GNU ld

mmitchel at gcc dot gnu dot org writes:

> We could have a --enable-comdat option, or, as you say, we could have something
> in the target configuration file.  I think your patch is the right idea, but I
> do think we need a --enable-comdat option, if we go that route, so that we can
> specifically indicate that a particular linker *does* support COMDAT.

Would you be ok with applying the current patch (mainline testing is in
progress, but as expected it correctly detected non COMDAT support on IRIX
6.5 with gas 2.16.1 and the MIPSpro ld) to mainline and the 4.1 branch now
(since it fixes a bootstrap failure) and implementing --enable-comdat in a
follow-up patch?

        Rainer


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26053

[Bug bootstrap/26053] [4.1/4.2 Regression] Misdetection of COMDAT group support with GNU as and non-GNU ld

[ro at gcc dot gnu dot org]

------- Comment #6 from ro at gcc dot gnu dot org  2006-02-14 16:46 -------
Subject: Bug 26053

Author: ro
Date: Tue Feb 14 16:46:04 2006
New Revision: 110985

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=110985
Log:
        PR bootstrap/26053
        * configure.ac (HAVE_COMDAT_GROUP): Don't assume non-GNU linkers
        support COMDAT group.
        * configure: Regenerate.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/configure
    trunk/gcc/configure.ac


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26053

[Bug bootstrap/26053] [4.1/4.2 Regression] Misdetection of COMDAT group support with GNU as and non-GNU ld

[ro at gcc dot gnu dot org]

------- Comment #7 from ro at gcc dot gnu dot org  2006-02-14 16:50 -------
Subject: Bug 26053

Author: ro
Date: Tue Feb 14 16:50:45 2006
New Revision: 110986

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=110986
Log:
        PR bootstrap/26053
        * configure.ac (HAVE_COMDAT_GROUP): Don't assume non-GNU linkers
        support COMDAT group.
        * configure: Regenerate.

Modified:
    branches/gcc-4_1-branch/gcc/ChangeLog
    branches/gcc-4_1-branch/gcc/configure
    branches/gcc-4_1-branch/gcc/configure.ac


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26053

[Bug bootstrap/26053] [4.1/4.2 Regression] Misdetection of COMDAT group support with GNU as and non-GNU ld

[ro at gcc dot gnu dot org]

-- 

ro at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |ro at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2006-02-01 01:38:23         |2006-02-14 16:55:27
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26053

[Bug bootstrap/26053] [4.1/4.2 Regression] Misdetection of COMDAT group support with GNU as and non-GNU ld

[ro at gcc dot gnu dot org]

------- Comment #8 from ro at gcc dot gnu dot org  2006-02-14 16:57 -------
Fixed for 4.1 and on mainline.


-- 

ro at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|                            |http://gcc.gnu.org/ml/gcc-
                   |                            |patches/2006-
                   |                            |02/msg00770.html
             Status|ASSIGNED                    |RESOLVED
           Keywords|build                       |patch
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26053

[Bug bootstrap/26053] [4.1/4.2 Regression] Misdetection of COMDAT group support with GNU as and non-GNU ld

[ebotcazou at gcc dot gnu dot org]

------- Comment #9 from ebotcazou at gcc dot gnu dot org  2006-03-02 14:15 -------
*** Bug 24345 has been marked as a duplicate of this bug. ***


-- 

ebotcazou at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bugzilla-gcc at
                   |                            |thewrittenword dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26053