From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp001-out.apm-internet.net (smtp001-out.apm-internet.net [85.119.248.222]) by sourceware.org (Postfix) with ESMTPS id 86B053858C60 for ; Fri, 24 Sep 2021 16:57:05 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 86B053858C60 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=sandoe.co.uk Authentication-Results: sourceware.org; spf=none smtp.mailfrom=sandoe.co.uk Received: (qmail 23320 invoked from network); 24 Sep 2021 16:57:03 -0000 X-APM-Out-ID: 16325026232331 X-APM-Authkey: 257869/1(257869/1) 4 Received: from unknown (HELO ?192.168.1.214?) (81.138.1.83) by smtp001.apm-internet.net with SMTP; 24 Sep 2021 16:57:03 -0000 From: Iain Sandoe Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.21\)) Subject: [PING}[PATCH] libgcc, emutls: Allow building weak definitions of the emutls functions. Date: Fri, 24 Sep 2021 17:57:03 +0100 References: To: GCC Patches In-Reply-To: Message-Id: <595871BA-D5D2-4A15-95A0-01D40585B50B@sandoe.co.uk> X-Mailer: Apple Mail (2.3445.104.21) X-Spam-Status: No, score=-15.3 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_COUK, KAM_DMARC_STATUS, KAM_LAZY_DOMAIN_SECURITY, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Sep 2021 16:57:07 -0000 Hi, as noted below the non-Darwin parts of this are trivial (and a no-OP). I=E2=80=99d like to apply this to start work towards solving Darwin=E2=80=99= s libgcc issues, OTOH, the two raised questions remain=E2=80=A6 thanks Iain > On 20 Sep 2021, at 09:25, Iain Sandoe wrote: >=20 > Hi, >=20 > The non-Darwin part of this patch is trivial but raises a couple of = questions >=20 > A/ > We define builtins to support emulated TLS. > These are defined with void * pointers > The implementation (in libgcc) uses the correct type (struct = __emutls_object *) > in both a forward declaration of the functions and in thier eventual = implementation. >=20 > This leads to a (long-standing, nothing new) complaint at build-time = about > the mismatch in the builtin/implementation decls. >=20 > AFAICT, there=E2=80=99s no way to fix that unless we introduce struct = __emutls_object * > as a built-in type? >=20 > B/=20 > It seems that a consequence of the mismatch in decls means that if I = apply > attributes to the decl (in the implementation file), they are ignored = and I have > to apply them to the definition in order for this to work. >=20 > This (B) is what the patch below does. >=20 > tested on powerpc,i686,x86_64-darwin, x86_64-linux > OK for master? > thanks, > Iain >=20 > If the current situation is that A or B indicates =E2=80=9Cthere=E2=80=99= s a bug=E2=80=9D, please could that > be considered as distinct from the current patch (which doesn=E2=80=99t = alter this in any > way) so that we can make progress on fixing Darwin libgcc issues. >=20 > =3D=3D=3D=3D=3D commit log >=20 > In order to better support use of the emulated TLS between objects = with > DSO dependencies and static-linked libgcc, allow a target to make weak > definitions. >=20 > Signed-off-by: Iain Sandoe >=20 > libgcc/ChangeLog: >=20 > * config.host: Add weak-defined emutls crt. > * config/t-darwin: Build weak-defined emutls objects. > * emutls.c (__emutls_get_address): Add optional attributes. > (__emutls_register_common): Likewise. > (EMUTLS_ATTR): New. > --- > libgcc/config.host | 2 +- > libgcc/config/t-darwin | 13 +++++++++++++ > libgcc/emutls.c | 17 +++++++++++++++-- > 3 files changed, 29 insertions(+), 3 deletions(-) >=20 > diff --git a/libgcc/config.host b/libgcc/config.host > index 6c34b13d611..a447ac7ae30 100644 > --- a/libgcc/config.host > +++ b/libgcc/config.host > @@ -215,7 +215,7 @@ case ${host} in > *-*-darwin*) > asm_hidden_op=3D.private_extern > tmake_file=3D"$tmake_file t-darwin ${cpu_type}/t-darwin t-libgcc-pic = t-slibgcc-darwin" > - extra_parts=3D"crt3.o libd10-uwfef.a crttms.o crttme.o" > + extra_parts=3D"crt3.o libd10-uwfef.a crttms.o crttme.o = libemutls_w.a" > ;; > *-*-dragonfly*) > tmake_file=3D"$tmake_file t-crtstuff-pic t-libgcc-pic t-eh-dw2-dip" > diff --git a/libgcc/config/t-darwin b/libgcc/config/t-darwin > index 14ae6b35a4e..d6f688d66d5 100644 > --- a/libgcc/config/t-darwin > +++ b/libgcc/config/t-darwin > @@ -15,6 +15,19 @@ crttme.o: $(srcdir)/config/darwin-crt-tm.c > LIB2ADDEH =3D $(srcdir)/unwind-dw2.c = $(srcdir)/config/unwind-dw2-fde-darwin.c \ > $(srcdir)/unwind-sjlj.c $(srcdir)/unwind-c.c >=20 > +# Make emutls weak so that we can deal with -static-libgcc, override = the > +# hidden visibility when this is present in libgcc_eh. > +emutls.o: HOST_LIBGCC2_CFLAGS +=3D \ > + -DEMUTLS_ATTR=3D'__attribute__((__weak__,__visibility__("default")))'= > +emutls_s.o: HOST_LIBGCC2_CFLAGS +=3D \ > + -DEMUTLS_ATTR=3D'__attribute__((__weak__,__visibility__("default")))'= > + > +# Make the emutls crt as a convenience lib so that it can be linked > +# optionally, use the shared version so that we can link with DSO. > +libemutls_w.a: emutls_s.o > + $(AR_CREATE_FOR_TARGET) $@ $< > + $(RANLIB_FOR_TARGET) $@ > + > # Patch to __Unwind_Find_Enclosing_Function for Darwin10. > d10-uwfef.o: $(srcdir)/config/darwin10-unwind-find-enc-func.c > $(crt_compile) -mmacosx-version-min=3D10.6 -c $< > diff --git a/libgcc/emutls.c b/libgcc/emutls.c > index ed2658170f5..d553a74728f 100644 > --- a/libgcc/emutls.c > +++ b/libgcc/emutls.c > @@ -50,7 +50,16 @@ struct __emutls_array > void **data[]; > }; >=20 > +/* EMUTLS_ATTR is provided to allow targets to build the emulated tls > + routines as weak definitions, for example. > + If there is no definition, fall back to the default. */ > +#ifndef EMUTLS_ATTR > +# define EMUTLS_ATTR > +#endif > + > +EMUTLS_ATTR > void *__emutls_get_address (struct __emutls_object *); > +EMUTLS_ATTR > void __emutls_register_common (struct __emutls_object *, word, word, = void *); >=20 > #ifdef __GTHREADS > @@ -123,7 +132,11 @@ emutls_alloc (struct __emutls_object *obj) > return ret; > } >=20 > -void * > +/* Despite applying the attribute to the declaration, in this case = the mis- > + match between the builtin's declaration [void * (*)(void *)] and = the > + implementation here, causes the decl. attributes to be discarded. = */ > + > +EMUTLS_ATTR void * > __emutls_get_address (struct __emutls_object *obj) > { > if (! __gthread_active_p ()) > @@ -187,7 +200,7 @@ __emutls_get_address (struct __emutls_object *obj) > #endif > } >=20 > -void > +EMUTLS_ATTR void > __emutls_register_common (struct __emutls_object *obj, > word size, word align, void *templ) > { > --=20 >=20