[Bug c++/36767] New: Segmentation fault with -fprofile-arcs -O2

[Bug c++/36767] New: Segmentation fault with -fprofile-arcs -O2

[gcc at dpinol dot com]

Hi,

The code at the bottom compiled with this line
  gcc -fprofile-arcs -O2  -c kk.cpp
causes this crash
  gcc: Internal error: Segmentation fault (program cc1plus)

It occurs on both:
 * Suse 11.0 with gcc (SUSE Linux) 4.3.1 20080507 (prerelease) [gcc-4_3-branch
revision 135036] (rpms: gcc43-4.3.1_20080507-6.1 and gcc-c++-4.3-39.1)

 * gcc 4.3.1 compiled with default options on Suse 10.2

best regards

#include <vector>


class PathElement {

public:
        float a;

        ~PathElement() {}
};

class PathPlanning {

public:

        std::vector<PathElement> v;

        PathPlanning();
};
PathPlanning offset2[2];


-- 
           Summary: Segmentation fault with -fprofile-arcs -O2
           Product: gcc
           Version: 4.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: gcc at dpinol dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] Segmentation fault with -fprofile-arcs -O2

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2008-07-09 12:32 -------
*** Bug 36768 has been marked as a duplicate of this bug. ***


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2008-07-09 12:53 -------
This one blows the stack recursing through

#40147 0x000000000065fa9a in mangle_decl (decl=0x7f398018d0a0)
    at /space/rguenther/src/svn/gcc-4_3-branch/gcc/cp/mangle.c:2655
2655      tree id = get_identifier_nocopy (mangle_decl_string (decl));
(gdb) up
#40148 0x0000000000d23724 in decl_assembler_name (decl=0x7f398018d0a0)
    at /space/rguenther/src/svn/gcc-4_3-branch/gcc/tree.c:304
304         lang_hooks.set_decl_assembler_name (decl);
(gdb) 
#40149 0x00000000006566c7 in write_unqualified_name (decl=0x7f398018d0a0)
    at /space/rguenther/src/svn/gcc-4_3-branch/gcc/cp/mangle.c:1104
1104        write_source_name (DECL_ASSEMBLER_NAME (decl));
(gdb) up
#40150 0x000000000065471b in write_unscoped_name (decl=0x7f398018d0a0)
    at /space/rguenther/src/svn/gcc-4_3-branch/gcc/cp/mangle.c:884
884           write_unqualified_name (decl);
(gdb) 
#40151 0x00000000006542d0 in write_name (decl=0x7f398018d0a0, 
    ignore_local_scope=0)
    at /space/rguenther/src/svn/gcc-4_3-branch/gcc/cp/mangle.c:818
818             write_unscoped_name (decl);
(gdb) 
#40152 0x0000000000653b0c in write_encoding (decl=0x7f398018d0a0)
    at /space/rguenther/src/svn/gcc-4_3-branch/gcc/cp/mangle.c:738
738       write_name (decl, /*ignore_local_scope=*/0);
(gdb) 
#40153 0x0000000000653329 in write_mangled_name (decl=0x7f398018d0a0, 
    top_level=1 '\001')
    at /space/rguenther/src/svn/gcc-4_3-branch/gcc/cp/mangle.c:708
708           write_encoding (decl);
(gdb) 
#40154 0x000000000065f6a4 in mangle_decl_string (decl=0x7f398018d0a0)
    at /space/rguenther/src/svn/gcc-4_3-branch/gcc/cp/mangle.c:2631
2631        write_mangled_name (decl, true);
(gdb) 
#40155 0x000000000065fa9a in mangle_decl (decl=0x7f398018d0a0)
    at /space/rguenther/src/svn/gcc-4_3-branch/gcc/cp/mangle.c:2655
2655      tree id = get_identifier_nocopy (mangle_decl_string (decl));
(gdb) 
#40156 0x0000000000d23724 in decl_assembler_name (decl=0x7f398018d0a0)
    at /space/rguenther/src/svn/gcc-4_3-branch/gcc/tree.c:304
304         lang_hooks.set_decl_assembler_name (decl);
...


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hubicka at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |ice-on-valid-code
   Last reconfirmed|0000-00-00 00:00:00         |2008-07-09 12:53:06
               date|                            |
            Summary|Segmentation fault with -   |[4.3/4.4 Regression]
                   |fprofile-arcs -O2           |Segmentation fault with -
                   |                            |fprofile-arcs -O2
   Target Milestone|---                         |4.3.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug middle-end/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c++                         |middle-end
      Known to fail|                            |4.3.1
      Known to work|                            |4.2.4
           Priority|P3                          |P1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug middle-end/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[jakub at gcc dot gnu dot org]

------- Comment #3 from jakub at gcc dot gnu dot org  2008-07-15 15:09 -------
Shorter testcase:
// { dg-do compile }
// { dg-options "-O2 -fprofile-arcs" }
struct A { A (); ~A (); };
A a[2];

What seems to be going on is that:
#0  create_temporary_var (type=0x7ffff3252780) at ../../gcc/cp/init.c:2613
#1  0x00000000005fd921 in get_temp_regvar (type=0x7ffff3252780,
init=0x7ffff324d500) at ../../gcc/cp/init.c:2635
#2  0x00000000005fdfad in build_vec_init (base=0x7ffff324d500,
maxindex=0x7ffff325c180, init=0x0, explicit_default_init_p=0 '\0',
from_array=0, complain=tf_warning_or_error) at ../../gcc/cp/init.c:2759
#3  0x00000000005f71be in build_aggr_init (exp=0x7ffff3209e60, init=0x0,
flags=0, complain=tf_warning_or_error) at ../../gcc/cp/init.c:1279
#4  0x000000000044b5de in build_aggr_init_full_exprs (decl=0x7ffff3209e60,
init=0x0, flags=0) at ../../gcc/cp/decl.c:4978
#5  0x000000000044c648 in check_initializer (decl=0x7ffff3209e60, init=0x0,
flags=0, cleanup=0x7fffffffde00) at ../../gcc/cp/decl.c:5104
#6  0x000000000044fc53 in cp_finish_decl (decl=0x7ffff3209e60, init=0x0,
init_const_expr_p=0 '\0', asmspec_tree=0x0, flags=0) at
../../gcc/cp/decl.c:5579

creates a VAR_DECL while current_function_decl == NULL.  Later on
one_static_initialization_or_destruction puts all its uses (and DECL_EXPR for
it) into the artificial __static_initialization_or_destruction, but from what I
can see nothing actually fixes up DECL_CONTEXT of the variable to the function
it has been put into.  If I manually set DECL_CONTEXT of these variables
in one_static_initialization_or_destruction, it compiles just fine.

If not and the vars make it through to the expander, they have DECL_NAME () ==
NULL and that leads to infinite recursion during mangling.

I wonder where is the best place to fix the contexts up though.
Either one_static_initialization_or_destruction could walk_tree init,
look for DECL_EXPRs with artificial VAR_DECLs with NULL DECL_CONTEXT, or
say cp-gimplify.c could do that.


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[dodji at gcc dot gnu dot org]

------- Comment #4 from dodji at gcc dot gnu dot org  2008-07-21 15:31 -------
Okay, I could reproduce this on gcc-4_3-branch. I will work on it, if nobody is
working on it already.


-- 

dodji at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |dodji at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2008-07-09 12:53:06         |2008-07-21 15:31:23
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[dodji at gcc dot gnu dot org]

------- Comment #5 from dodji at gcc dot gnu dot org  2008-07-21 15:43 -------
By the way, I cannot reproduce this on trunk, changeset 138026.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[dodji at gcc dot gnu dot org]

------- Comment #6 from dodji at gcc dot gnu dot org  2008-07-22 18:25 -------
@jakub: I confirm that doing:

if (!DECL_CONTEXT (decl))
    { 
      DECL_CONTEXT (decl) = current_function_decl;
    }
at the beginning of one_static_initialization_or_destruction() allows the
compilation to not crash.

At that point, the name of current_function_decl is effectively
"__static_initialization_and_destruction_0".

I am not sure if setting DECL_CONTEXT (decl) is safe to do, because the
DECL_CONTEXT (decl) being NULL means the variable happened in the global
namespace. Doing DECL_CONTEXT (decl) = current_function_decl makes us loose
that information.

On the other hand, one_static_initialization_or_destruction() is called at the
end of the parsing+semantic analysis phase, so loosing that information might
not be harmful (I am not sure). In which case, this candidate fix might be
enough.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[dodji at gcc dot gnu dot org]

------- Comment #7 from dodji at gcc dot gnu dot org  2008-07-25 00:03 -------
Created an attachment (id=15957)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15957&action=view)
fixes DECL_CONTEXT() of the temporary variables in the initialiser

So this patch seems to make the crash go away for me.

I still need to add add some asserts in the mangler to prevent it from
recursing ad infinitum when a VAR_DECL has a NULL name.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[dodji at gcc dot gnu dot org]

------- Comment #8 from dodji at gcc dot gnu dot org  2008-07-25 00:04 -------
By the way, I can reproduce the problem on trunk. I think I was lacking sleep
when I first said I could not reproduce it on trunk. Sorry.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[jason at gcc dot gnu dot org]

------- Comment #9 from jason at gcc dot gnu dot org  2008-07-25 02:32 -------
I accidentally checked in the demangler patch with my defaulted/deleted
functions work today, so you don't need to worry about that.  :)

As for the patch itself, does it work to scan for DECL_EXPRs instead of the
decls themselves?  I'm a bit concerned about the current patch touching decls
that it shouldn't.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[dodji at gcc dot gnu dot org]

------- Comment #10 from dodji at gcc dot gnu dot org  2008-07-28 07:19 -------
Created an attachment (id=15968)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15968&action=view)
try scanning DECL_EXPR instead of VAR_DECLs directly.

@Jason: I have tried scanning DECL_EXPR and setting only VAR_DECL that are
children of DECL_EXPR. It does not work. This patch is what I have done. Maybe
I have done something bad ?

My understanding is that by walking DECL_EXPRs and getting their associated
VAR_DECL (using DECL_EXPR_DECL), all VAR_DECLs should be touched because every
single variable must be declared at least once.

So, are there cases where a VAR_DECL has never had a parent DECL_EXPR ?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[dodji at gcc dot gnu dot org]

------- Comment #11 from dodji at gcc dot gnu dot org  2008-07-28 10:52 -------
Created an attachment (id=15969)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15969&action=view)
update vars more specifically, adding BIND_EXPR

After talking with Jakub, it appeared that I was forgetting to update VAR_DECLS
that were attached to a BIND_EXPR.
Walking those VAR_DECLS appears to fix the problem.

Regtesting now. Will update the patch with a proper testcase when regtesting
passes.

Please feel free to comment in the meantime.


-- 

dodji at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #15968|0                           |1
        is obsolete|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[jakub at gcc dot gnu dot org]

------- Comment #12 from jakub at gcc dot gnu dot org  2008-07-28 15:00 -------
There are unneeded {} pairs, when there is just one statement in for/if, you
should just write
  if (something)
    DECL_CONTEXT (x) = current_function_decl;
and similar for
  for (.....)
    if (something)
      DECL_CONTEXT (var) = current_function_decl.

Also, I think it is unnecessary to pass current_function_decl as data to the
callback, current_function_decl is accessible in the callback too.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[dodji at gcc dot gnu dot org]

------- Comment #13 from dodji at gcc dot gnu dot org  2008-07-28 17:01 -------
Created an attachment (id=15972)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15972&action=view)
reworked patch

Reworked patch to walk BIND_EXPR_VARs only. I think there is no need to walk
VAR_DECLs via DECL_EXPR() if we walk BIND_EXPR_VARs.

The patch seems to work, regtested on trunk, x86_64.

@jakub: thanks for your comments. I did fix the patch accordingly.


-- 

dodji at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #15957|0                           |1
        is obsolete|                            |
  Attachment #15969|0                           |1
        is obsolete|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[dodji at gcc dot gnu dot org]

------- Comment #14 from dodji at gcc dot gnu dot org  2008-07-30 13:09 -------
Subject: Bug 36767

Author: dodji
Date: Wed Jul 30 13:07:50 2008
New Revision: 138308

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=138308
Log:
2008-07-30  Dodji Seketeli  <dseketel@redhat.com>

        PR c++/36767
        * decl2.c (fix_temporary_vars_context_r): New function.
         (one_static_initialization_or_destruction): Make sure temporary
         variables part of the initialiser have their DECL_CONTEXT()
         properly set.


Added:
    trunk/gcc/testsuite/g++.dg/parse/crash42.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/decl2.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[dodji at gcc dot gnu dot org]

------- Comment #15 from dodji at gcc dot gnu dot org  2008-07-30 13:19 -------
Subject: Bug 36767

Author: dodji
Date: Wed Jul 30 13:18:31 2008
New Revision: 138309

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=138309
Log:
2008-07-30  Dodji Seketeli  <dseketel@redhat.com>

        PR c++/36767
        * decl2.c (fix_temporary_vars_context_r): New function.
         (one_static_initialization_or_destruction): Make sure temporary
         variables part of the initialiser have their DECL_CONTEXT()
         properly set.


Added:
    branches/gcc-4_3-branch/gcc/testsuite/g++.dg/parse/crash41.C
Modified:
    branches/gcc-4_3-branch/gcc/cp/ChangeLog
    branches/gcc-4_3-branch/gcc/cp/decl2.c
    branches/gcc-4_3-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767

[Bug c++/36767] [4.3/4.4 Regression] Segmentation fault with -fprofile-arcs -O2

[jakub at gcc dot gnu dot org]

------- Comment #16 from jakub at gcc dot gnu dot org  2008-07-30 13:53 -------
Fixed, thanks.


-- 

jakub at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36767