Re: [patch lto/c++/middle-end/windows]: Fix handling of dllexport for LTO as externally_visible

[Kai Tietz <ktietz70 at googlemail dot com>]

2010/11/16 Jan Hubicka <hubicka@ucw.cz>:
>> On Tue, Nov 16, 2010 at 11:46 AM, Kai Tietz <Kai.Tietz@onevision.com> wrote:
>> > Hello,
>> >
>> > this patch introduces an new flag for dllexport (likewise to the already
>> > existing DLLIMPORT flag) to structure tree_decl_with_vis in tree.h header..
>> > As some places still dependent on checking explicit for
>> > dllimport/dllexport attribute, I didn't omitted here the the attribute
>> > node copy. This is maybe something for 4.7 gcc.
>> >
>> > ChangeLog
>> >
>> > ? ? ? ?* config/i386/winnt-cxx.c (maybe_add_dllexport): Set
>> > DECL_DLLEXPORT_P.
>> > ? ? ? ?* config/i386/winnt.c (i386_pe_determine_dllexport_p): Use
>> > DECL_DLLEXPORT_P
>> > ? ? ? ?instead of doing attribute lookup.
>> > ? ? ? ?* tree.c (merge_dllimport_decl_attributes): Likewise.
>> > ? ? ? ?(handle_dll_attribute): Set DECL_DLLEXPORT_P flag.
>> > ? ? ? ?* lto-streamer-in.c (unpack_ts_decl_with_vis_value_fields):
>> > Restore dllexport flag.
>> > ? ? ? ?* lto-streamer-out.c (pack_ts_decl_with_vis_value_fields): Save
>> > dllexport flag.
>> > ? ? ? ?* tree-emutls.c (new_emutls_decl): Copy DECL_DLLEXPORT_P flag.
>> > ? ? ? ?* tree.h (tree_decl_with_vis):Add new member dllexport_flag.
>> > ? ? ? ?(DECL_DLLEXPORT_P): New macro.
>> > ? ? ? ?* ipa.c (cgraph_externally_visible_p): Check for DECL_DLLEXPORT_P.
>> > ? ? ? ?(varpool_externally_visible_p): Likewise.
>> > ? ? ? ?*cp/optimize.c (maybe_clone_body): Copy DECL_DLLEXPORT_P, too.
>> >
>> > Tested for x86_64-w64-mingw32, i686-w64-mingw32, and i686-pc-cygwin. Ok
>> > for apply?
>>
>> What's the difference between externally_visible and dllexport?
>>
>> @@ -3121,6 +3125,7 @@ struct GTY(()) tree_decl_with_vis {
>> ? unsigned in_text_section : 1;
>> ? unsigned in_constant_pool : 1;
>> ? unsigned dllimport_flag : 1;
>> + unsigned dllexport_flag : 1;
>> ? /* Don't belong to VAR_DECL exclusively. ?*/
>> ? unsigned weak_flag : 1;
>>
>> please keep 1) flags in 8 bit groups, 2) add it below the right comment
>> (it doesn't belong to VAR_DECLs exclusively, right?)
>>
>> That said, why not simply add externally_visible when seeing dllexport?
>
> I would not be too offended by doing that.
>
>> Why not make externally_visible use a flag (or intergrate that with
>> visibility support)?
>
> We already have flag in cgraph node, so we search for it in declaration
> constant number of times (I think twice, once for visibility pass and once for
> whole_program_visibility), so adding flag seems bit redundant.
>
> We can also just search for dllexport attribute at the same place, it would
> not be terribly expensive either.
>
> Honza
>>
>> Richard.
>>
>> > Regards,
>> > ?i.A. Kai Tietz
>> >
>> > | ?(\_/) ?This is Bunny. Copy and paste Bunny
>> > | (='.'=) into your signature to help him gain
>> > | (")_(") world domination.
>> >
>> >
>

So, I moved the new flag at the end of the structure to keep alignment
of 8 bit blocks. Additionally I add a testcase for dllexport and
whole-program.

Ok for apply?

Regards,
Kai

-- 
|? (\_/) This is Bunny. Copy and paste
| (='.'=) Bunny into your signature to help
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