[Bug debug/55641] debug info for the type of a reference declared with a typedef has spurious 'const'

["aoliva at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55641

--- Comment #12 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Author: aoliva
Date: Fri Aug 12 07:11:36 2016
New Revision: 239402

URL: https://gcc.gnu.org/viewcvs?rev=239402&root=gcc&view=rev
Log:
[PR55641] drop spurious const_type from reference_type variables

Although C++ reference types, denoted by DW_TAG_reference_type in
DWARFv2+ debug info, are unchangeable, we output names of reference type
with DW_TAG_const_type, because internally we mark such variables as
TREE_READONLY.  That's an internal implementation detail that shouldn't
leak to debug information.  This patch fixes this.

for  gcc/ChangeLog

        PR debug/55641
        * dwarf2out.c (decl_quals): Don't map TREE_READONLY to
        TYPE_QUAL_CONST in reference-typed decls.

for  gcc/testsuite/ChangeLog

        PR debug/55641
        * g++.dg/debug/dwarf2/ref-1.C: New.

Added:
    trunk/gcc/testsuite/g++.dg/debug/dwarf2/ref-1.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/dwarf2out.c
    trunk/gcc/testsuite/ChangeLog