[Bug c++/54420] New: Segmentation in decl_mangling_context

[Bug c++/54420] New: Segmentation in decl_mangling_context

[lukeocamden at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54420

             Bug #: 54420
           Summary: Segmentation in decl_mangling_context
    Classification: Unclassified
           Product: gcc
           Version: 4.7.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: lukeocamden@gmail.com


Created attachment 28107
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28107
Preprocessed source file

Discovered when compiling llvm+lldb. Preprocessed file attached. Stack trace:

#0  0x000000000058f3b3 in decl_mangling_context (decl=0x2aaaabf38508) at
../.././gcc/cp/mangle.c:759
#1  decl_mangling_context (decl=0x2aaaabf38508) at ../.././gcc/cp/mangle.c:749
#2  0x00000000005963a4 in write_name (decl=0x2aaaabf38508,
ignore_local_scope=ignore_local_scope@entry=0)
    at ../.././gcc/cp/mangle.c:795
#3  0x00000000005931b4 in write_class_enum_type (type=<optimized out>) at
../.././gcc/cp/mangle.c:2424
#4  write_type (type=type@entry=0x2aaaabf4e7e0) at ../.././gcc/cp/mangle.c:1903
#5  0x0000000000596db9 in mangle_special_for_type (type=0x2aaaabf4e7e0,
code=0xd3042e "TV") at ../.././gcc/cp/mangle.c:3445
#6  0x000000000051062e in get_vtable_name (type=0x2aaaabf4e7e0) at
../.././gcc/cp/class.c:709
...

[Bug c++/54420] Segmentation fault in decl_mangling_context

[markus at trippelsdorf dot de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54420

Markus Trippelsdorf <markus at trippelsdorf dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |markus at trippelsdorf dot
                   |                            |de

--- Comment #1 from Markus Trippelsdorf <markus at trippelsdorf dot de> 2012-08-30 14:33:01 UTC ---
gcc-4.8 is also affected.

Reduced:

class __lambda
{
    virtual bool is_sub ();
};

[Bug c++/54420] [4.6/4.7/4.8 Regression] Segmentation fault in decl_mangling_context

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54420

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code
      Known to work|                            |4.1.2
   Target Milestone|---                         |4.6.4
            Summary|Segmentation fault in       |[4.6/4.7/4.8 Regression]
                   |decl_mangling_context       |Segmentation fault in
                   |                            |decl_mangling_context

[Bug c++/54420] [4.6/4.7/4.8 Regression] Segmentation fault in decl_mangling_context

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54420

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

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

--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> 2012-09-04 22:16:57 UTC ---
The name __lambda, like all names beginning with "__", is reserved to the
implementation.

In addition, some identifiers are reserved for use by C++ implementations and
standard libraries (17.6.4.3.2) and shall not be used otherwise; no diagnostic
is required.

— Each name that contains a double underscore _ _ or begins with an underscore
followed by an uppercase letter (2.12) is reserved to the implementation for
any use.

I'll fix 4.8 to avoid crashing on this testcase, but I don't want to change the
release branches.

[Bug c++/54420] [4.6/4.7/4.8 Regression] Segmentation fault in decl_mangling_context

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54420

--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> 2012-09-05 04:17:09 UTC ---
Author: jason
Date: Wed Sep  5 04:16:58 2012
New Revision: 190961

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=190961
Log:
    PR c++/54420
    * cp-tree.h (LAMBDANAME_P): Remove.
    (LAMBDA_TYPE_P): Check CLASSTYPE_LAMBDA_EXPR instead.
    * cp-lang.c (cxx_dwarf_name): Likewise.
    * error.c (dump_aggr_type): Likewise.
    * semantics.c (begin_lambda_type): Set CLASSTYPE_LAMBDA_EXPR sooner.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-intname.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/cp-lang.c
    trunk/gcc/cp/cp-tree.h
    trunk/gcc/cp/error.c
    trunk/gcc/cp/name-lookup.c
    trunk/gcc/cp/semantics.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/54420] [4.6/4.7/4.8 Regression] Segmentation fault in decl_mangling_context

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54420

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

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

--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> 2012-09-05 04:20:53 UTC ---
Fixed.

[Bug c++/54420] [4.6/4.7/4.8 Regression] Segmentation fault in decl_mangling_context

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54420

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.6.4                       |4.8.0

[Bug c++/54420] [4.6/4.7/4.8 Regression] Segmentation fault in decl_mangling_context

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54420

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |patrik.h.hagglund at gmail
                   |                            |dot com

--- Comment #5 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-09-18 13:47:54 UTC ---
*** Bug 54616 has been marked as a duplicate of this bug. ***

[Bug c++/54420] [4.6/4.7/4.8 Regression] Segmentation fault in decl_mangling_context

[patrik.h.hagglund at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54420

--- Comment #6 from Patrik Hägglund <patrik.h.hagglund at gmail dot com> 2012-09-19 10:27:37 UTC ---
Jason Merrill wrote:
> In addition, some identifiers are reserved for use by C++ implementations and
> standard libraries (17.6.4.3.2) and shall not be used otherwise; no diagnostic
> is required.

> [...] I don't want to change the release branches.

You seems to imply that "no diagnostic is required" implies "the behavior of
the compiler is undefined". This seems odd.

[Bug c++/54420] [4.6/4.7/4.8 Regression] Segmentation fault in decl_mangling_context

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54420

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|ice-on-valid-code           |ice-on-invalid-code
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-09-19 10:35:58 UTC ---
The important thing is "and shall not be used otherwise", which means the
testcase is invalid, and there is a compiler crash on invalid code that is
fixed on the compiler trunk, but the fix is too risky for the lower priority of
the bug (compared to if it was e.g. a crash on valid code or miscompilation).

[Bug c++/54420] [4.6/4.7/4.8 Regression] Segmentation fault in decl_mangling_context

[patrik.h.hagglund at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54420

--- Comment #8 from Patrik Hägglund <patrik.h.hagglund at gmail dot com> 2012-09-19 11:04:43 UTC ---
(In reply to comment #7)
> the fix is too risky for the lower priority of the bug

This is a good explanation! :-)