[Bug debug/63239] New: DWARF does not represent C++ deleted methods

[Bug debug/63239] New: DWARF does not represent C++ deleted methods

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63239

            Bug ID: 63239
           Summary: DWARF does not represent C++ deleted methods
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mpolacek at gcc dot gnu.org

C++11 has implicitly deleted functions.  These are declared with the = delete
specifier, and their usage in the program is forbidden.

struct A
{ 
  int i;
  A() = delete;
};
A a = { 42 };

However, it seems that currently the deleted functions are emitted like any
other.

[Bug debug/63239] DWARF does not represent C++ deleted methods

[mark at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63239

--- Comment #2 from Mark Wielaard <mark at gcc dot gnu.org> ---
Author: mark
Date: Sun Oct  5 15:25:03 2014
New Revision: 215901

URL: https://gcc.gnu.org/viewcvs?rev=215901&root=gcc&view=rev
Log:
PR debug/63239 Add DWARF representation for C++11 deleted member function.

include/ChangeLog

    * dwarf2.def (DW_AT_GNU_deleted): New attribute.

gcc/ChangeLog

    * dwarf2out.c (gen_subprogram_die): When a member function is
    explicitly deleted then add a DW_AT_GNU_deleted attribute.
    * langhooks.h (struct lang_hooks_for_decls): Add
    function_decl_deleted_p langhook.
    * langhooks-def.h (LANG_HOOKS_FUNCTION_DECL_DELETED_P): Define.
    (LANG_HOOKS_DECLS): Add LANG_HOOKS_FUNCTION_DECL_DELETED_P.

gcc/cp/ChangeLog

    * cp-objcp-common.h (LANG_HOOKS_FUNCTION_DECL_DELETED_P): Define.
    (cp_function_decl_deleted_p): New prototype.
    * cp-objcp-common.c (cp_function_deleted_p): New function.

gcc/testsuite/ChangeLog

    * g++.dg/debug/dwarf2/deleted-member-function.C: New testcase.

Added:
    trunk/gcc/testsuite/g++.dg/debug/dwarf2/deleted-member-function.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/cp-objcp-common.c
    trunk/gcc/cp/cp-objcp-common.h
    trunk/gcc/dwarf2out.c
    trunk/gcc/langhooks-def.h
    trunk/gcc/langhooks.h
    trunk/gcc/testsuite/ChangeLog
    trunk/include/ChangeLog
    trunk/include/dwarf2.def

[Bug debug/63239] DWARF does not represent C++ deleted methods

[mark at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63239

Mark Wielaard <mark at gcc dot gnu.org> changed:

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

--- Comment #3 from Mark Wielaard <mark at gcc dot gnu.org> ---
https://gcc.gnu.org/ml/gcc-patches/2014-10/msg00272.html

[Bug debug/63239] DWARF does not represent C++ deleted methods

[fxcoudert at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63239

Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
   Last reconfirmed|                            |2014-11-21
                 CC|                            |fxcoudert at gcc dot gnu.org
         Resolution|FIXED                       |---
     Ever confirmed|0                           |1

--- Comment #4 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
The testcase fails on x86_64-apple-darwin14. With "g++ -O -std=c++11 -g -dA
a.c", we have the following optimized tree dump:

;; Function void bar() (_Z3barv, funcdef_no=3, decl_uid=2126, cgraph_uid=3,
symbol_order=3)
void bar() ()
{
  <bb 2>:
  # DEBUG this => &foo
  return;
}

The assembler (see attachment) does not contain DW_AT_GNU_deleted.

[Bug debug/63239] DWARF does not represent C++ deleted methods

[fxcoudert at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63239

--- Comment #5 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
Created attachment 34063
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34063&action=edit
Assembler generated at -O -std=c++11 -g -dA

[Bug debug/63239] DWARF does not represent C++ deleted methods

[mark at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63239

--- Comment #6 from Mark Wielaard <mark at gcc dot gnu.org> ---
It looks like for some reason Darwin defaults to some ancient (v2) strict
version of DWARF. Please try adding -gno-strict-dwarf -gdwarf-4 to
gcc/testsuite/g++.dg/debug/dwarf2/deleted-member-function.C dg-options.

[Bug debug/63239] DWARF does not represent C++ deleted methods

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63239

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Mark Wielaard from comment #6)
> It looks like for some reason Darwin defaults to some ancient (v2) strict
> version of DWARF. Please try adding -gno-strict-dwarf -gdwarf-4 to
> gcc/testsuite/g++.dg/debug/dwarf2/deleted-member-function.C dg-options.

The reason for that is that Darwin has a set of tools that crash or otherwise
break on valid DWARF 3 or DWARF 4 or various extensions.  So using -gdwarf-2
and -gstrict-dwarf by default is necessary because of badly written toolchain.

[Bug debug/63239] DWARF does not represent C++ deleted methods

[fxcoudert at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63239

--- Comment #9 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
Author: fxcoudert
Date: Fri Nov 21 13:27:57 2014
New Revision: 217918

URL: https://gcc.gnu.org/viewcvs?rev=217918&root=gcc&view=rev
Log:
    PR debug/63239
    * g++.dg/debug/dwarf2/deleted-member-function.C: Pass
    -gno-strict-dwarf on darwin.

Modified:
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/g++.dg/debug/dwarf2/deleted-member-function.C

[Bug debug/63239] DWARF does not represent C++ deleted methods

[fxcoudert at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63239

--- Comment #8 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #7)
> So using
> -gdwarf-2 and -gstrict-dwarf by default is necessary because of badly
> written toolchain.

I had tried -gdwarf-4, but didn't know about -gstrict-dwarf. Will commit the
obvious patch, then.

[Bug debug/63239] DWARF does not represent C++ deleted methods

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63239

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
You should pass -gno-strict-dwarf unconditionally, I think vxworks has similar
defaults as darwin.

[Bug debug/63239] DWARF does not represent C++ deleted methods

[fxcoudert at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63239

--- Comment #11 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
Author: fxcoudert
Date: Fri Nov 21 13:32:08 2014
New Revision: 217920

URL: https://gcc.gnu.org/viewcvs?rev=217920&root=gcc&view=rev
Log:
    PR debug/63239
    * g++.dg/debug/dwarf2/deleted-member-function.C: Pass
    -gno-strict-dwarf.

Modified:
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/g++.dg/debug/dwarf2/deleted-member-function.C

[Bug debug/63239] DWARF does not represent C++ deleted methods

[fxcoudert at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63239

Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> changed:

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

--- Comment #12 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #10)
> You should pass -gno-strict-dwarf unconditionally, I think vxworks has
> similar defaults as darwin.

OK, it's true it cannot hurt as we're not calling the assembler anyway.