[Bug c++/55245] New: Compiler segfault when compiling the small test case

[Bug c++/55245] New: Compiler segfault when compiling the small test case

[xinliangli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

             Bug #: 55245
           Summary: Compiler segfault when compiling the small test case
    Classification: Unclassified
           Product: gcc
           Version: 4.7.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: xinliangli@gmail.com


Compiling the following program without any option, gcc segfaults:

get.cc: In member function 'virtual void Test2::TestBody()':
get.cc:22:27: internal compiler error: Segmentation fault


The problem is that one array type Vector2_f[2]'s size field is reset to zero
during gimplify_type_sizes by one of its variant (which has null size).

The problem does not show up in trunk compiler.  Was this fixed explicitly in
trunk or it happens to work by luck?

David



template <typename VType> class Vector2 { };
typedef Vector2<float> Vector2_f;

void GetR( const Vector2_f mosaic_position[3]);

class Test1 {
 private: virtual void TestBody();
};

void Test1::TestBody() {
  Vector2_f mosaic_position[2][1];   // (1)
}

class Test2 {
 private: virtual void TestBody();
};

int tri;
void Test2::TestBody() {
  Vector2_f mosaic_position[2][3] = { };
  GetR(mosaic_position[tri]);
}

[Bug c++/55245] Compiler segfault when compiling the small test case

[xinliangli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

davidxl <xinliangli at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Version|4.7.3                       |4.8.0

--- Comment #1 from davidxl <xinliangli at gmail dot com> 2012-11-09 00:42:55 UTC ---
The problem actually exists in main line compiler too.

[Bug c++/55245] Compiler segfault when compiling the small test case

[xinliangli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

--- Comment #2 from davidxl <xinliangli at gmail dot com> 2012-11-09 06:05:43 UTC ---
(In reply to comment #1)
> The problem actually exists in main line compiler too.


This is another test case.

Segfaults without option, but builds ok with -DOK.

The problem seems to be that the main variant of the array type
Vector2<float>[2] does not have size, while the variant Vector2_f[2] has. The
variant's size later gets reset to 0 (from main variant).

David

template <typename VType> class Vector2 {
 public:
  Vector2();
  VType x() const;
};
typedef Vector2<float> Vector2_f;
void GetR(const Vector2_f mosaic_position[3]);
template <class C> struct DefaultDeleter {
   float  GetColorTexCoord(Vector2_f &tex_coord) const  {
    return tex_coord.x();
  }
};

class GetT { private: virtual void TestBody(); };

void GetT::TestBody() {
#ifdef OK
  Vector2<float> mosaic_position[2][3] = { };
#else
  Vector2_f mosaic_position[2][3] = { };
#endif
}

[Bug c++/55245] [4.6/4.7/4.8 Regression] Compiler segfault when compiling the small test case

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-11-09
                 CC|                            |jakub at gcc dot gnu.org
   Target Milestone|---                         |4.6.4
            Summary|Compiler segfault when      |[4.6/4.7/4.8 Regression]
                   |compiling the small test    |Compiler segfault when
                   |case                        |compiling the small test
                   |                            |case
     Ever Confirmed|0                           |1

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-11-09 09:06:25 UTC ---
Started with http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=170853 aka
PR48029 fix.

[Bug c++/55245] [4.6/4.7/4.8 Regression] Compiler segfault when compiling a small test case

[dnovillo at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

Diego Novillo <dnovillo at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dnovillo at gcc dot gnu.org

--- Comment #4 from Diego Novillo <dnovillo at gcc dot gnu.org> 2012-11-21 00:52:57 UTC ---
David's analysis is correct.  The type of the element at the point of the
failure is not a complete type.

At this point, I think all the types should've been completed, so I'm not sure
why this one still isn't.  Jason, this patchlet (which is very likely papering
over the issue) allows the file to build.

Index: gimplify.c
===================================================================
--- gimplify.c  (revision 193508)
+++ gimplify.c  (working copy)
@@ -2123,6 +2123,8 @@
          if (TREE_OPERAND (t, 3) == NULL_TREE)
            { 
              tree elmt_type = TREE_TYPE (TREE_TYPE (TREE_OPERAND (t, 0)));
+             if (!COMPLETE_TYPE_P (elmt_type))
+               layout_type (elmt_type);
              tree elmt_size = unshare_expr (array_ref_element_size (t));
              tree factor = size_int (TYPE_ALIGN_UNIT (elmt_type));

In this case, we have

t ==> mosaic_position[tri]
elmt_type ==> struct Vector2_f[3], but we cannot compute its element size
because it has not yet been laid out.

Jason, what would be a better place to make sure the type is laid out?


Thanks.  Diego.

[Bug c++/55245] [4.6/4.7/4.8 Regression] Compiler segfault when compiling a small test case

[xinliangli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

--- Comment #5 from davidxl <xinliangli at gmail dot com> 2012-11-21 16:17:27 UTC ---
Should the main variant types gets laid out in gimplify_type_sizes, when the
variant's type has size, but the main variant is incomplete? 

David

[Bug c++/55245] [4.6/4.7/4.8 Regression] Compiler segfault when compiling a small test case

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-11-26 09:49:23 UTC ---
I'd say it should be the FE's responsibility to layout all needed types, so it
should be done either somewhere when the type ARRAY_REF is created or
finalized, or in cp-gimplify.c at latest.

[Bug c++/55245] [4.6/4.7/4.8 Regression] Compiler segfault when compiling a small test case

[dnovillo at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

--- Comment #7 from Diego Novillo <dnovillo at gcc dot gnu.org> 2012-11-26 18:35:43 UTC ---
Author: dnovillo
Date: Mon Nov 26 18:35:38 2012
New Revision: 193825

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=193825
Log:
Google ref b/7500842.

2012-11-26  Diego Novillo  <dnovillo@google.com>

    * gimplify.c: Work around for PR 55245.

testsuite/ChangeLog.google-integration
    * g++.dg/pr55245.C: New.



Added:
    branches/google/gcc-4_7/gcc/testsuite/g++.dg/pr55245.C
Modified:
    branches/google/gcc-4_7/gcc/ChangeLog.google-4_7
    branches/google/gcc-4_7/gcc/gimplify.c
    branches/google/gcc-4_7/gcc/testsuite/ChangeLog.google-4_7

[Bug c++/55245] [4.6/4.7/4.8 Regression] Compiler segfault when compiling a small test case

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code
           Priority|P3                          |P2

[Bug c++/55245] [4.6 Regression] Compiler segfault when compiling a small test case

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu.org
            Summary|[4.6/4.7/4.8 Regression]    |[4.6 Regression] Compiler
                   |Compiler segfault when      |segfault when compiling a
                   |compiling a small test case |small test case

--- Comment #8 from Jason Merrill <jason at gcc dot gnu.org> 2012-12-06 22:18:18 UTC ---
Fixed for 4.7 and 4.8 by patch for bug 55032.

[Bug c++/55245] [4.6 Regression] Compiler segfault when compiling a small test case

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

--- Comment #9 from Jason Merrill <jason at gcc dot gnu.org> 2012-12-07 04:54:23 UTC ---
Author: jason
Date: Fri Dec  7 04:54:12 2012
New Revision: 194283

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=194283
Log:
add PR 55245 marker

Modified:
    trunk/gcc/ChangeLog

[Bug c++/55245] [4.6 Regression] Compiler segfault when compiling a small test case

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
         AssignedTo|unassigned at gcc dot       |jason at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #10 from Jason Merrill <jason at gcc dot gnu.org> 2012-12-07 05:14:34 UTC ---
Fix applied for 4.6.4 as well.

[Bug c++/55245] [4.6 Regression] Compiler segfault when compiling a small test case

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

--- Comment #11 from Jason Merrill <jason at gcc dot gnu.org> 2013-01-02 19:03:17 UTC ---
Author: jason
Date: Wed Jan  2 19:03:04 2013
New Revision: 194811

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=194811
Log:
    PR c++/55804
    PR c++/55032
    PR c++/55245
    * tree.c (build_array_type_1): Revert earlier change.
    * cp/tree.c (build_cplus_array_type): Copy layout information
    to main variant if necessary.

Added:
    trunk/gcc/testsuite/g++.dg/init/array33.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/tree.c
    trunk/gcc/tree.c

[Bug c++/55245] [4.6 Regression] Compiler segfault when compiling a small test case

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

--- Comment #13 from Jason Merrill <jason at gcc dot gnu.org> 2013-01-02 19:04:07 UTC ---
Author: jason
Date: Wed Jan  2 19:03:46 2013
New Revision: 194813

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=194813
Log:
    PR c++/55804
    PR c++/55032
    PR c++/55245
    * tree.c (build_array_type_1): Revert earlier change.
    * cp/tree.c (build_cplus_array_type): Copy layout information
    to main variant if necessary.

Added:
    branches/gcc-4_6-branch/gcc/testsuite/g++.dg/init/array33.C
Modified:
    branches/gcc-4_6-branch/gcc/ChangeLog
    branches/gcc-4_6-branch/gcc/cp/ChangeLog
    branches/gcc-4_6-branch/gcc/cp/tree.c
    branches/gcc-4_6-branch/gcc/tree.c

[Bug c++/55245] [4.6 Regression] Compiler segfault when compiling a small test case

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55245

--- Comment #12 from Jason Merrill <jason at gcc dot gnu.org> 2013-01-02 19:03:55 UTC ---
Author: jason
Date: Wed Jan  2 19:03:37 2013
New Revision: 194812

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=194812
Log:
    PR c++/55804
    PR c++/55032
    PR c++/55245
    * tree.c (build_array_type_1): Revert earlier change.
    * cp/tree.c (build_cplus_array_type): Copy layout information
    to main variant if necessary.

Added:
    branches/gcc-4_7-branch/gcc/testsuite/g++.dg/init/array33.C
Modified:
    branches/gcc-4_7-branch/gcc/ChangeLog
    branches/gcc-4_7-branch/gcc/cp/ChangeLog
    branches/gcc-4_7-branch/gcc/cp/tree.c
    branches/gcc-4_7-branch/gcc/tree.c