[Bug c++/94223] [10 Regression] -fcompare-debug -O0 failure on cpp1z/init-statement6.C

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94223

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

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

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
gimplify.c does:
4941                if (!DECL_NAME (object))
4942                  DECL_NAME (object) = create_tmp_var_name ("C");
4943                walk_tree (&DECL_INITIAL (object), force_labels_r, NULL,
NULL);
4944    
4945                /* ??? C++ doesn't automatically append a .<number> to the
4946                   assembler name, and even when it does, it looks at FE
private
4947                   data structures to figure out what that number should
be,
4948                   which are not set for this variable.  I suppose this is
4949                   important for local statics for inline functions, which
aren't
4950                   "local" in the object file sense.  So in order to get a
unique
4951                   TU-local symbol, we must invoke the lhd version now.  */
4952                lhd_set_decl_assembler_name (object);

and lhd_set_decl_assembler_name does:
169           const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
170           char *label;
171     
172           ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
173           id = get_identifier (label);

The problem is that DECL_UID isn't stable across -fcompare-debug, we only
guarantee that the comparisons of the DECL_UIDs are the same between
corresponding decls, but -g can have larger gaps.

grep ASM_FORMAT_PRIVATE_NAME.*DECL_UID * */* config/*/* 2>/dev/null
langhooks.c:      ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
d/decl.cc:  ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
lto/lto-lang.c:      ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));

Not sure what to do, shall we have some GTY counter used for these instead of
DECL_UID which we'd bump when we've done this?