On Wed, Nov 12, 2014 at 5:31 PM, Jakub Jelinek <ja...@redhat.com> wrote: > On Wed, Nov 12, 2014 at 04:46:39PM +0100, Mark Wielaard wrote: >> I don't mind changing the language hook to return the actual DW_LANG_* >> constant directly, that seems like a nice cleanup. >> >> But I don't think we can just replace TRANSLATION_UNIT_LANGUAGE and >> lang_hooks.name. The name is (explicitly) const and isused to identify > > It is const char *name; , so it isn't const, just what it points is const. > So you can change if (just after parsing the options set > lang_hooks.name = "GNU C11"; > or similar). > >> the frontend used for a particular language in various places (for >> example some backends seem to use it to write out some language/abi >> information, or to detect when to use IEEE compliance mode, pch uses it >> to match whether a header can be reused, the constant folder uses it to >> make some decisions, etc. > > If Richard prefers to use lang_hooks.name, I'd just change all the users > of lang_hooks.name or TRANSLATION_UNIT_LANGUAGE that need changing. > For PCH it is ok as is, parsing a header can depend on the language version, > for the cases that strcmp (lang_hooks.name, "GNU C++") I'd replace it > with strncmp (lang_hooks.name, "GNU C++", 7), you are not going to change > the ObjC/ObjC++ stuff, just in dwarf2out.c in addition to handling the new > names you also need to do something better for the LTO merging of > TRANSLATION_UNIT_LANGUAGE - say if merging "GNU C", "GNU C99" and "GNU C11", > pick up the newest out of those, if C++ is mixed into it, pick probably the > highest C++ version.
Right. (that lang_hooks.name checks in fold-const.c really really really have to go!) Btw, I have nothing against changing TRANSLATION_UNIT_LANGUAGE to DW_LANG_* directly - we only use it for choosing the language of the dwarf unit. This would of course mean to change its initialization from TRANSLATION_UNIT_LANGUAGE (tu) = lang_hooks.name; to sth like TRANSLATION_UNIT_LANGUAGE (tu) = lang_hooks.dw_lang; which means adding a langhook (thus more similar to your original patch). Richard. >> >> So shall I change the patch so that the lang hook explicitly encodes the >> DW_LANG_* constant/language standard variant in use, but keep >> lang_hooks.name as is to not break any other users? > > Jakub
