On Wed, 25 Mar 2020, Jakub Jelinek wrote:
> Hi!
>
> As mentioned in the PR, we don't guarantee DECL_UID to be the same between
> corresponding decls in -g and -g0 builds, -g can create more decls and all
> that is guaranteed is that the DECL_UIDs of the corresponding decls compare
> the same.
> The following testcase gets a -fcompare-debug failure because these
> functions use DECL_UID as the number in ASM_FORMAT_PRIVATE_NAME.
>
> The patch fixes it by using just a sequential number there instead.
> I don't think this can be called during PCH writing, this only happens for
> non-public decls and the C/C++ FEs shouldn't mangling those at that point
> (furthermore C++ FE uses a different set_decl_assembler_name hook and this
> one is something only the gimplifier calls on C.NNNN temporaries.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
Thanks,
Richard.
> 2020-03-25 Jakub Jelinek <ja...@redhat.com>
>
> PR c++/94223
> * langhooks.c (lhd_set_decl_assembler_name): Use a static ulong
> counter instead of DECL_UID.
>
> * lto-lang.c (lto_set_decl_assembler_name): Use a static ulong
> counter instead of DECL_UID.
>
> * g++.dg/opt/pr94223.C: New test.
>
> --- gcc/langhooks.c.jj 2020-01-12 11:54:36.670409531 +0100
> +++ gcc/langhooks.c 2020-03-24 16:05:26.728284808 +0100
> @@ -160,16 +160,17 @@ lhd_set_decl_assembler_name (tree decl)
>
> Can't use just the variable's own name for a variable whose scope
> is less than the whole compilation. Concatenate a distinguishing
> - number - we use the DECL_UID. */
> + number. */
>
> if (TREE_PUBLIC (decl) || DECL_FILE_SCOPE_P (decl))
> id = targetm.mangle_decl_assembler_name (decl, DECL_NAME (decl));
> else
> {
> const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
> + static unsigned long num;
> char *label;
>
> - ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
> + ASM_FORMAT_PRIVATE_NAME (label, name, num++);
> id = get_identifier (label);
> }
>
> --- gcc/lto/lto-lang.c.jj 2020-01-12 11:54:36.678409411 +0100
> +++ gcc/lto/lto-lang.c 2020-03-24 13:55:10.463826320 +0100
> @@ -1179,8 +1179,9 @@ lto_set_decl_assembler_name (tree decl)
> {
> const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
> char *label;
> + static unsigned long num;
>
> - ASM_FORMAT_PRIVATE_NAME (label, name, DECL_UID (decl));
> + ASM_FORMAT_PRIVATE_NAME (label, name, num++);
> id = get_identifier (label);
> }
>
> --- gcc/testsuite/g++.dg/opt/pr94223.C.jj 2020-03-24 16:03:42.069863475
> +0100
> +++ gcc/testsuite/g++.dg/opt/pr94223.C 2020-03-24 16:04:53.327788620
> +0100
> @@ -0,0 +1,5 @@
> +// PR c++/94223
> +// { dg-do compile }
> +// { dg-options "-O0 -std=c++2a -fcompare-debug" }
> +
> +#include "../cpp1z/init-statement6.C"
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
