Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754007AbcCKGUI (ORCPT ); Fri, 11 Mar 2016 01:20:08 -0500 Received: from conssluserg003.nifty.com ([202.248.44.41]:30562 "EHLO conssluserg003-v.nifty.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751030AbcCKGT6 (ORCPT ); Fri, 11 Mar 2016 01:19:58 -0500 X-Nifty-SrcIP: [209.85.160.181] MIME-Version: 1.0 In-Reply-To: <20160307000329.a51b2b8f4fdb0e60344f0b20@gmail.com> References: <20160307000208.1bec3e7dc874489d1b4fcbb4@gmail.com> <20160307000329.a51b2b8f4fdb0e60344f0b20@gmail.com> Date: Fri, 11 Mar 2016 15:19:33 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v5 1/5] Shared library support From: Masahiro Yamada To: Emese Revfy Cc: Linux Kbuild mailing list , pageexec@freemail.hu, spender@grsecurity.net, kernel-hardening@lists.openwall.com, Michal Marek , Kees Cook , linux@rasmusvillemoes.dk, fengguang.wu@intel.com, dvyukov@google.com, Linux Kernel Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6332 Lines: 160 Hi Emese, 2016-03-07 8:03 GMT+09:00 Emese Revfy : > Infrastructure for building independent shared library targets. > This effectively also reverts commit 62e2210798ed38928ab24841e8b4878a > (Masahiro Yamada, kbuild: drop shared library support from Makefile.host). > > Signed-off-by: Emese Revfy > --- > scripts/Makefile.build | 2 +- > scripts/Makefile.clean | 3 ++- > scripts/Makefile.host | 69 +++++++++++++++++++++++++++++++++++++++++++++++++- > 3 files changed, 71 insertions(+), 3 deletions(-) > > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index 130a452..bd2a31e 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -60,7 +60,7 @@ endif > endif > > # Do not include host rules unless needed > -ifneq ($(hostprogs-y)$(hostprogs-m),) > +ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),) > include scripts/Makefile.host > endif > > diff --git a/scripts/Makefile.clean b/scripts/Makefile.clean > index 55c96cb..e4e88ab 100644 > --- a/scripts/Makefile.clean > +++ b/scripts/Makefile.clean > @@ -38,7 +38,8 @@ subdir-ymn := $(addprefix $(obj)/,$(subdir-ymn)) > __clean-files := $(extra-y) $(extra-m) $(extra-) \ > $(always) $(targets) $(clean-files) \ > $(host-progs) \ > - $(hostprogs-y) $(hostprogs-m) $(hostprogs-) > + $(hostprogs-y) $(hostprogs-m) $(hostprogs-) \ > + $(hostlibs-y) $(hostlibs-m) $(hostlibs-) > > __clean-files := $(filter-out $(no-clean-files), $(__clean-files)) > > diff --git a/scripts/Makefile.host b/scripts/Makefile.host > index 133edfa..4d180d9 100644 > --- a/scripts/Makefile.host > +++ b/scripts/Makefile.host > @@ -20,7 +20,25 @@ > # Will compile qconf as a C++ program, and menu as a C program. > # They are linked as C++ code to the executable qconf > > +# hostprogs-y := conf > +# conf-objs := conf.o libkconfig.so > +# libkconfig-objs := expr.o type.o > +# Will create a shared library named libkconfig.so that consists of > +# expr.o and type.o (they are both compiled as C code and the object files > +# are made as position independent code). > +# conf.c is compiled as a C program, and conf.o is linked together with > +# libkconfig.so as the executable conf. > +# Note: Shared libraries consisting of C++ files are not supported I do not see any use-case for the above. This series adds cases for "foo.so" as a final target. As an alternative, you can add needed build rules into tools/gcc/Makefile, not scripts/Makefile.host I guess these rule won't be used in other places. > +# hostcc-option > +# Usage: cflags-y += $(call hostcc-option,-march=winchip-c6,-march=i586) > + > +hostcc-option = $(call try-run,\ > + $(HOSTCC) $(HOSTCFLAGS) $(HOST_EXTRACFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2)) > + > __hostprogs := $(sort $(hostprogs-y) $(hostprogs-m)) > +__hostlibs := $(sort $(hostlibs-y) $(hostlibs-m)) > +__hostcxxlibs := $(sort $(hostcxxlibs-y) $(hostcxxlibs-m)) > > # C code > # Executables compiled from a single .c file > @@ -42,6 +60,19 @@ host-cxxmulti := $(foreach m,$(__hostprogs),$(if $($(m)-cxxobjs),$(m))) > # C++ Object (.o) files compiled from .cc files > host-cxxobjs := $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs))) > > +# Shared libaries (only .c supported) > +# Shared libraries (.so) - all .so files referenced in "xxx-objs" > +host-cshlib := $(sort $(filter %.so, $(host-cobjs))) useless. > +host-cshlib += $(sort $(filter %.so, $(__hostlibs))) > +host-cxxshlib := $(sort $(filter %.so, $(__hostcxxlibs))) > +# Remove .so files from "xxx-objs" > +host-cobjs := $(filter-out %.so,$(host-cobjs)) > +host-cxxobjs := $(filter-out %.so,$(host-cxxobjs)) > + > +# Object (.o) files used by the shared libaries > +host-cshobjs := $(sort $(foreach m,$(host-cshlib),$($(m:.so=-objs)))) > +host-cxxshobjs := $(sort $(foreach m,$(host-cxxshlib),$($(m:.so=-objs)))) > + > # output directory for programs/.o files > # hostprogs-y := tools/build may have been specified. > # Retrieve also directory of .o files from prog-objs or prog-cxxobjs notation > @@ -56,6 +87,10 @@ host-cmulti := $(addprefix $(obj)/,$(host-cmulti)) > host-cobjs := $(addprefix $(obj)/,$(host-cobjs)) > host-cxxmulti := $(addprefix $(obj)/,$(host-cxxmulti)) > host-cxxobjs := $(addprefix $(obj)/,$(host-cxxobjs)) > +host-cshlib := $(addprefix $(obj)/,$(host-cshlib)) > +host-cxxshlib := $(addprefix $(obj)/,$(host-cxxshlib)) > +host-cshobjs := $(addprefix $(obj)/,$(host-cshobjs)) > +host-cxxshobjs := $(addprefix $(obj)/,$(host-cxxshobjs)) > host-objdirs := $(addprefix $(obj)/,$(host-objdirs)) > > obj-dirs += $(host-objdirs) > @@ -124,5 +159,37 @@ quiet_cmd_host-cxxobjs = HOSTCXX $@ > $(host-cxxobjs): $(obj)/%.o: $(src)/%.cc FORCE > $(call if_changed_dep,host-cxxobjs) > > +# Compile .c file, create position independent .o file > +# host-cshobjs -> .o > +quiet_cmd_host-cshobjs = HOSTCC -fPIC $@ > + cmd_host-cshobjs = $(HOSTCC) $(hostc_flags) -fPIC -c -o $@ $< > +$(host-cshobjs): $(obj)/%.o: $(src)/%.c FORCE > + $(call if_changed_dep,host-cshobjs) > + > +# Compile .c file, create position independent .o file > +# host-cxxshobjs -> .o > +quiet_cmd_host-cxxshobjs = HOSTCXX -fPIC $@ > + cmd_host-cxxshobjs = $(HOSTCXX) $(hostcxx_flags) -fPIC -c -o $@ $< > +$(host-cxxshobjs): $(obj)/%.o: $(src)/%.c FORCE > + $(call if_changed_dep,host-cxxshobjs) > + > +# Link a shared library, based on position independent .o files > +# *.o -> .so shared library (host-cshlib) > +quiet_cmd_host-cshlib = HOSTLLD -shared $@ > + cmd_host-cshlib = $(HOSTCC) $(HOSTLDFLAGS) -shared -o $@ \ > + $(addprefix $(obj)/,$($(@F:.so=-objs))) \ > + $(HOST_LOADLIBES) $(HOSTLOADLIBES_$(@F)) > +$(host-cshlib): $(obj)/%: $(host-cshobjs) FORCE > + $(call if_changed,host-cshlib) Could you use $(call multi-depend, ...) if you need to handle multi-object please? Please refer to commit c8589d1e9e01 and commit 97e3226e6e984c8. But, I still do not see any gcc-plugin that is large enough to be linked from multiple objects. -- Best Regards Masahiro Yamada