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Re: [C++ patch] Set attributes for C++ runtime library calls
- From: Jan Hubicka <hubicka at ucw dot cz>
- To: Gabriel Dos Reis <gdr at integrable-solutions dot net>
- Cc: Jan Hubicka <hubicka at ucw dot cz>, Alexander Monakov <amonakov at ispras dot ru>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Jason Merrill <jason at redhat dot com>
- Date: Thu, 22 Aug 2013 17:39:58 +0200
- Subject: Re: [C++ patch] Set attributes for C++ runtime library calls
- References: <20130822131927 dot GA18084 at kam dot mff dot cuni dot cz> <CAAiZkiDRZj-Fzy2+zUo9Z2B5ShvJ6K_duNyX1SKfrEZeX1NNZQ at mail dot gmail dot com> <alpine dot LNX dot 2 dot 00 dot 1308221836460 dot 30125 at monopod dot intra dot ispras dot ru> <20130822152111 dot GB19256 at kam dot mff dot cuni dot cz> <CAAiZkiA5wyTn0A_eMZ8d-crnq0KY0ut6R1ffh+2xsTp51dkWEg at mail dot gmail dot com>
> > So the existing program needs to overwrite libsup++ symbol like we do with malloc?
> > Of course with user defineed malloc function we should not propagate the attribute,
> > but I think we could have it when we end up calling the runtime.
> I suspect the question is whether our current infrastructure permits
> to distinguish
> between declaration of 'operator new' we supply, and 'operator new' defined by
> user. The way we currently arrange for user-defined 'operator new' to take
> over is that it is something that is done at linktime, (so is LTO
> prepared for this?)
I think so (I am not expert though :))
The operator new we supply is called _Znwm and I want the particular decl with
assembler name _Znwm to have malloc attribute. I get it right, it is the
declaration we build by
newtype = cp_build_type_attribute_variant (ptr_ftype_sizetype, newattrs);
newtype = build_exception_variant (newtype, new_eh_spec);
deltype = cp_build_type_attribute_variant (void_ftype_ptr, extvisattr);
deltype = build_exception_variant (deltype, empty_except_spec);
push_cp_library_fn (NEW_EXPR, newtype);
push_cp_library_fn (VEC_NEW_EXPR, newtype);
User's new will be different declarations with different assembler name. It is
up to user to care about malloc attributes or whatever.
Aren't user allocator also allowed to make their own exceptions in addition to throw (std::bad_alloc);?
> and ours is searched last.
> > Honza
> >> Alexander