[Bug debug/46955] New: Missing DW_AT_const_value from DW_TAG_template_value_parameter

[Bug debug/46955] New: Missing DW_AT_const_value from DW_TAG_template_value_parameter

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46955

           Summary: Missing DW_AT_const_value from
                    DW_TAG_template_value_parameter
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: dodji@gcc.gnu.org


struct S { int f; };
template<int S::*MP> struct T { };
T<&S::f> v;

For v's type, I just see:

 <2><4f>: Abbrev Number: 6 (DW_TAG_template_value_param)
    <50>   DW_AT_name        : MP       
    <53>   DW_AT_type        : <0x58>   

That is, this parameter has no value.

This is because the DWARF emitter doesn't know how to handle the C++ specific
PTRMEM_CST node that represenst the argument &S::f at that point. That
PTRMEM_CST needs to be folded further into something low level enough for the
DWARF emitter to understand, while keeping its OFFSET_TYPE type meaning it's a
pointer-to-member constant.

This has been first reported in a comment of PR debug/41736, but I am opening
this specific bug for it as I think those two bugs are different.

[Bug debug/46955] Missing DW_AT_const_value from DW_TAG_template_value_parameter

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46955

Dodji Seketeli <dodji at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2010.12.15 10:21:25
         AssignedTo|unassigned at gcc dot       |dodji at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

[Bug debug/46955] Missing DW_AT_const_value from DW_TAG_template_value_parameter

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46955

--- Comment #1 from Dodji Seketeli <dodji at gcc dot gnu.org> 2010-12-16 17:09:21 UTC ---
Candidate patch posted to
http://gcc.gnu.org/ml/gcc-patches/2010-12/msg01276.html

[Bug debug/46955] Missing DW_AT_const_value from DW_TAG_template_value_parameter

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46955

--- Comment #2 from Dodji Seketeli <dodji at gcc dot gnu.org> 2011-01-11 21:20:13 UTC ---
Author: dodji
Date: Tue Jan 11 21:20:07 2011
New Revision: 168681

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=168681
Log:
Fix PR debug/46955

gcc/cp/

    * cp-lang.c (get_template_innermost_arguments_folded)
    (get_template_argument_pack_elems_folded)
    (template_arg_needs_folding, fold_cplus_constants): New static
    functions.
    (LANG_HOOKS_GET_INNERMOST_GENERIC_ARGS): Set this hook to
    get_template_innermost_arguments_folded.
    (LANG_HOOKS_GET_ARGUMENT_PACK_ELEMS): Set this hook to
    get_template_argument_pack_elems_folded.

gcc/testsuite/

    * g++.dg/debug/dwarf2/template-params-8.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/debug/dwarf2/template-params-8.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/cp-lang.c
    trunk/gcc/testsuite/ChangeLog

[Bug debug/46955] Missing DW_AT_const_value from DW_TAG_template_value_parameter

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46955

Dodji Seketeli <dodji at gcc dot gnu.org> changed:

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

--- Comment #3 from Dodji Seketeli <dodji at gcc dot gnu.org> 2011-01-11 21:24:07 UTC ---
Fixed in trunk (4.6).