* [Buildroot] [PATCH] gcc/gcc-final: pass TARGET_CFLAGS flags to configure with --enable-cxx-flags @ 2015-06-01 14:37 Max Filippov 2016-01-09 22:08 ` Yann E. MORIN 0 siblings, 1 reply; 6+ messages in thread From: Max Filippov @ 2015-06-01 14:37 UTC (permalink / raw) To: buildroot Currently only TARGET_ABI flags are passed to the final compiler configure script and only when building for Xtensa. Since libstdc++ is a normal library it should be built with full TARGET_CFLAGS on all targets. Pass TARGET_CFLAGS flags to gcc-final configure script for all targets in the --enable-cxx-flags parameter. Suggested-by: Arnout Vandecappelle <arnout@mind.be> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> --- package/gcc/gcc-final/gcc-final.mk | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/package/gcc/gcc-final/gcc-final.mk b/package/gcc/gcc-final/gcc-final.mk index 8d7009b..59c8708 100644 --- a/package/gcc/gcc-final/gcc-final.mk +++ b/package/gcc/gcc-final/gcc-final.mk @@ -185,8 +185,6 @@ endef HOST_GCC_FINAL_POST_INSTALL_HOOKS += HOST_GCC_FINAL_INSTALL_USR_LIBS endif -ifeq ($(BR2_xtensa),y) -HOST_GCC_FINAL_CONF_OPTS += --enable-cxx-flags="$(TARGET_ABI)" -endif +HOST_GCC_FINAL_CONF_OPTS += --enable-cxx-flags="$(TARGET_CFLAGS)" $(eval $(host-autotools-package)) -- 1.8.1.4 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [Buildroot] [PATCH] gcc/gcc-final: pass TARGET_CFLAGS flags to configure with --enable-cxx-flags 2015-06-01 14:37 [Buildroot] [PATCH] gcc/gcc-final: pass TARGET_CFLAGS flags to configure with --enable-cxx-flags Max Filippov @ 2016-01-09 22:08 ` Yann E. MORIN 2016-03-08 23:22 ` Arnout Vandecappelle 0 siblings, 1 reply; 6+ messages in thread From: Yann E. MORIN @ 2016-01-09 22:08 UTC (permalink / raw) To: buildroot Max, All, On 2015-06-01 17:37 +0300, Max Filippov spake thusly: > Currently only TARGET_ABI flags are passed to the final compiler > configure script and only when building for Xtensa. Since libstdc++ is a > normal library it should be built with full TARGET_CFLAGS on all > targets. > > Pass TARGET_CFLAGS flags to gcc-final configure script for all targets > in the --enable-cxx-flags parameter. > > Suggested-by: Arnout Vandecappelle <arnout@mind.be> > Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> So, I finally had a look at this patch. I've tested it to build a gcc-4.9 + glibc-2.21 + binutils-2.24 toolchain with C++ support, which then was used to suessfully build Qt5base (which is quite a heavy C++ user). However, I'd like to understand what this is all about. In gcc.mk, we do: GCC_COMMON_TARGET_CXXFLAGS = $(TARGET_CXXFLAGS) [...] HOST_GCC_COMMON_CONF_ENV += CXXFLAGS_FOR_TARGET="$(GCC_COMMON_TARGET_CXXFLAGS)" So it looks like we were already passing the proper CXXFLAGS to gcc (we only filter-out problematic flags, like -Os on broken gcc-4.5 for PPC). So, what are we supposed to gain/loose with this change? As a side note, we should not have to pass TARGET_ABI either, since it is part of TARGET_CFLAGS and as shown above, it is already part of the CFLAGS_FOR_TARGET that we pass gcc. Any explanations? Something that I missed? Regards, Yann E. MORIN. > --- > package/gcc/gcc-final/gcc-final.mk | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/package/gcc/gcc-final/gcc-final.mk b/package/gcc/gcc-final/gcc-final.mk > index 8d7009b..59c8708 100644 > --- a/package/gcc/gcc-final/gcc-final.mk > +++ b/package/gcc/gcc-final/gcc-final.mk > @@ -185,8 +185,6 @@ endef > HOST_GCC_FINAL_POST_INSTALL_HOOKS += HOST_GCC_FINAL_INSTALL_USR_LIBS > endif > > -ifeq ($(BR2_xtensa),y) > -HOST_GCC_FINAL_CONF_OPTS += --enable-cxx-flags="$(TARGET_ABI)" > -endif > +HOST_GCC_FINAL_CONF_OPTS += --enable-cxx-flags="$(TARGET_CFLAGS)" > > $(eval $(host-autotools-package)) > -- > 1.8.1.4 > > _______________________________________________ > buildroot mailing list > buildroot at busybox.net > http://lists.busybox.net/mailman/listinfo/buildroot -- .-----------------.--------------------.------------------.--------------------. | Yann E. MORIN | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: | | +33 662 376 056 | Software Designer | \ / CAMPAIGN | ___ | | +33 223 225 172 `------------.-------: X AGAINST | \e/ There is no | | http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL | v conspiracy. | '------------------------------^-------^------------------^--------------------' ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Buildroot] [PATCH] gcc/gcc-final: pass TARGET_CFLAGS flags to configure with --enable-cxx-flags 2016-01-09 22:08 ` Yann E. MORIN @ 2016-03-08 23:22 ` Arnout Vandecappelle 2016-03-10 9:37 ` Max Filippov 0 siblings, 1 reply; 6+ messages in thread From: Arnout Vandecappelle @ 2016-03-08 23:22 UTC (permalink / raw) To: buildroot Hi Max, On 01/09/16 23:08, Yann E. MORIN wrote: > Max, All, > > On 2015-06-01 17:37 +0300, Max Filippov spake thusly: >> Currently only TARGET_ABI flags are passed to the final compiler >> configure script and only when building for Xtensa. Since libstdc++ is a >> normal library it should be built with full TARGET_CFLAGS on all >> targets. >> >> Pass TARGET_CFLAGS flags to gcc-final configure script for all targets >> in the --enable-cxx-flags parameter. >> >> Suggested-by: Arnout Vandecappelle <arnout@mind.be> >> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> > > So, I finally had a look at this patch. I've tested it to build a > gcc-4.9 + glibc-2.21 + binutils-2.24 toolchain with C++ support, which > then was used to suessfully build Qt5base (which is quite a heavy C++ > user). > > However, I'd like to understand what this is all about. > > In gcc.mk, we do: > > GCC_COMMON_TARGET_CXXFLAGS = $(TARGET_CXXFLAGS) > [...] > HOST_GCC_COMMON_CONF_ENV += CXXFLAGS_FOR_TARGET="$(GCC_COMMON_TARGET_CXXFLAGS)" > > So it looks like we were already passing the proper CXXFLAGS to gcc (we > only filter-out problematic flags, like -Os on broken gcc-4.5 for PPC). > > So, what are we supposed to gain/loose with this change? > > As a side note, we should not have to pass TARGET_ABI either, since it > is part of TARGET_CFLAGS and as shown above, it is already part of the > CFLAGS_FOR_TARGET that we pass gcc. > > Any explanations? Something that I missed? I checked in the gcc source and also couldn't find a reason why the CXXFLAGS_FOR_TARGET wouldn't work. Since you haven't replied to this, I've marked your patch as rejected in patchwork. If you do still fel it is warranted, please repost with a satisfactory explanation. Regards, Arnout > > Regards, > Yann E. MORIN. > >> --- >> package/gcc/gcc-final/gcc-final.mk | 4 +--- >> 1 file changed, 1 insertion(+), 3 deletions(-) >> >> diff --git a/package/gcc/gcc-final/gcc-final.mk b/package/gcc/gcc-final/gcc-final.mk >> index 8d7009b..59c8708 100644 >> --- a/package/gcc/gcc-final/gcc-final.mk >> +++ b/package/gcc/gcc-final/gcc-final.mk >> @@ -185,8 +185,6 @@ endef >> HOST_GCC_FINAL_POST_INSTALL_HOOKS += HOST_GCC_FINAL_INSTALL_USR_LIBS >> endif >> >> -ifeq ($(BR2_xtensa),y) >> -HOST_GCC_FINAL_CONF_OPTS += --enable-cxx-flags="$(TARGET_ABI)" >> -endif >> +HOST_GCC_FINAL_CONF_OPTS += --enable-cxx-flags="$(TARGET_CFLAGS)" >> >> $(eval $(host-autotools-package)) >> -- >> 1.8.1.4 >> >> _______________________________________________ >> buildroot mailing list >> buildroot at busybox.net >> http://lists.busybox.net/mailman/listinfo/buildroot > -- Arnout Vandecappelle arnout at mind be Senior Embedded Software Architect +32-16-286500 Essensium/Mind http://www.mind.be G.Geenslaan 9, 3001 Leuven, Belgium BE 872 984 063 RPR Leuven LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle GPG fingerprint: 7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Buildroot] [PATCH] gcc/gcc-final: pass TARGET_CFLAGS flags to configure with --enable-cxx-flags 2016-03-08 23:22 ` Arnout Vandecappelle @ 2016-03-10 9:37 ` Max Filippov 2016-03-10 9:46 ` Arnout Vandecappelle 0 siblings, 1 reply; 6+ messages in thread From: Max Filippov @ 2016-03-10 9:37 UTC (permalink / raw) To: buildroot Arnout, Yann, On Wed, Mar 9, 2016 at 2:22 AM, Arnout Vandecappelle <arnout@mind.be> wrote: > On 01/09/16 23:08, Yann E. MORIN wrote: >> On 2015-06-01 17:37 +0300, Max Filippov spake thusly: >>> >>> Currently only TARGET_ABI flags are passed to the final compiler >>> configure script and only when building for Xtensa. Since libstdc++ is a >>> normal library it should be built with full TARGET_CFLAGS on all >>> targets. >>> >>> Pass TARGET_CFLAGS flags to gcc-final configure script for all targets >>> in the --enable-cxx-flags parameter. >>> >>> Suggested-by: Arnout Vandecappelle <arnout@mind.be> >>> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> >> >> >> So, I finally had a look at this patch. I've tested it to build a >> gcc-4.9 + glibc-2.21 + binutils-2.24 toolchain with C++ support, which >> then was used to suessfully build Qt5base (which is quite a heavy C++ >> user). >> >> However, I'd like to understand what this is all about. >> >> In gcc.mk, we do: >> >> GCC_COMMON_TARGET_CXXFLAGS = $(TARGET_CXXFLAGS) >> [...] >> HOST_GCC_COMMON_CONF_ENV += >> CXXFLAGS_FOR_TARGET="$(GCC_COMMON_TARGET_CXXFLAGS)" >> >> So it looks like we were already passing the proper CXXFLAGS to gcc (we >> only filter-out problematic flags, like -Os on broken gcc-4.5 for PPC). >> >> So, what are we supposed to gain/loose with this change? >> >> As a side note, we should not have to pass TARGET_ABI either, since it >> is part of TARGET_CFLAGS and as shown above, it is already part of the >> CFLAGS_FOR_TARGET that we pass gcc. >> >> Any explanations? Something that I missed? > > > I checked in the gcc source and also couldn't find a reason why the > CXXFLAGS_FOR_TARGET wouldn't work. Since you haven't replied to this, I've > marked your patch as rejected in patchwork. If you do still fel it is > warranted, please repost with a satisfactory explanation. Sorry, took me too long to answer the first mail. AFAICS neither gcc-4.8.x nor gcc-4.9.x propagate CXXFLAGS_FOR_TARGET to CXXFLAGS for builds of libstdc++. gcc-5.x however does. Compare the following build log excerpts for libstdc++ of gcc-4.8, gcc-4.9 and gcc-5 (I've reverted 2dcab526a97d and c44cf2cc97df before running these builds): gcc-4.8: make[3]: Entering directory '/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.8.5/build/xtensa-buildroot-linux-uclibc/libstdc++-v3' /usr/bin/make "AR_FLAGS=rc" "CC_FOR_BUILD=/usr/bin/gcc" "CC_FOR_TARGET=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.8.5/build/./gcc/xgcc -B/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.8.5/build/./gcc/" "CFLAGS=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2" "CXXFLAGS=-O2 -I/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/include -D_GNU_SOURCE" "CFLAGS_FOR_BUILD=-O2 -I/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/include" "CFLAGS_FOR_TARGET=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2" "INSTALL=/usr/bin/install -c" "INSTALL_DATA=/usr/bin/install -c -m 644" "INSTALL_PROGRAM=/usr/bin/install -c" "INSTALL_SCRIPT=/usr/bin/install -c" "LDFLAGS=" "LIBCFLAGS=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2" "LIBCFLAGS_FOR_TARGET=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2" "MAKE=/usr/bin/make" "MAKEINFO=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.8.5/missing makeinfo --split-size=5000000 --split-size=5000000 " "SHELL=/bin/bash" "RUNTESTFLAGS=" "exec_prefix=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr" "infodir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/share/info" "libdir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/lib" "includedir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/include" "prefix=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr" "tooldir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc" "gxx_include_dir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc/include/c++/4.8.5" "AR=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc/bin/ar" "AS=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.8.5/build/./gcc/as" "LD=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.8.5/build/./gcc/collect-ld" "RANLIB=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc/bin/ranlib" "NM=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.8.5/build/./gcc/nm" "NM_FOR_BUILD=" "NM_FOR_TARGET=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc/bin/nm" "DESTDIR=" "WERROR=" all-recursive gcc-4.9: make[3]: Entering directory '/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.9.3/build/xtensa-buildroot-linux-uclibc/libstdc++-v3' /usr/bin/make "AR_FLAGS=rc" "CC_FOR_BUILD=/usr/bin/gcc" "CC_FOR_TARGET=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.9.3/build/./gcc/xgcc -B/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.9.3/build/./gcc/" "CFLAGS=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2" "CXXFLAGS=-O2 -I/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/include -D_GNU_SOURCE" "CFLAGS_FOR_BUILD=-O2 -I/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/include" "CFLAGS_FOR_TARGET=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2" "INSTALL=/usr/bin/install -c" "INSTALL_DATA=/usr/bin/install -c -m 644" "INSTALL_PROGRAM=/usr/bin/install -c" "INSTALL_SCRIPT=/usr/bin/install -c" "LDFLAGS=" "LIBCFLAGS=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2" "LIBCFLAGS_FOR_TARGET=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2" "MAKE=/usr/bin/make" "MAKEINFO=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.9.3/missing makeinfo --split-size=5000000 --split-size=5000000 " "SHELL=/bin/bash" "RUNTESTFLAGS=" "exec_prefix=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr" "infodir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/share/info" "libdir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/lib" "includedir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/include" "prefix=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr" "tooldir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc" "gxx_include_dir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc/include/c++/4.9.3" "AR=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc/bin/ar" "AS=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.9.3/build/./gcc/as" "LD=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.9.3/build/./gcc/collect-ld" "RANLIB=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc/bin/ranlib" "NM=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-4.9.3/build/./gcc/nm" "NM_FOR_BUILD=" "NM_FOR_TARGET=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc/bin/nm" "DESTDIR=" "WERROR=" all-recursive gcc-5: make[3]: Entering directory '/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-5.3.0/build/xtensa-buildroot-linux-uclibc/libstdc++-v3' /usr/bin/make "AR_FLAGS=rc" "CC_FOR_BUILD=/usr/bin/gcc" "CC_FOR_TARGET=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-5.3.0/build/./gcc/xgcc -B/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-5.3.0/build/./gcc/" "CFLAGS=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2" "CXXFLAGS=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2 -D_GNU_SOURCE" "CFLAGS_FOR_BUILD=-O2 -I/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/include" "CFLAGS_FOR_TARGET=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2" "INSTALL=/usr/bin/install -c" "INSTALL_DATA=/usr/bin/install -c -m 644" "INSTALL_PROGRAM=/usr/bin/install -c" "INSTALL_SCRIPT=/usr/bin/install -c" "LDFLAGS=" "LIBCFLAGS=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2" "LIBCFLAGS_FOR_TARGET=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os -g2" "MAKE=/usr/bin/make" "MAKEINFO=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-5.3.0/missing makeinfo --split-size=5000000 --split-size=5000000 " "SHELL=/bin/bash" "RUNTESTFLAGS=" "exec_prefix=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr" "infodir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/share/info" "libdir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/lib" "includedir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/include" "prefix=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr" "tooldir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc" "gxx_include_dir=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc/include/c++/5.3.0" "AR=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc/bin/ar" "AS=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-5.3.0/build/./gcc/as" "LD=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-5.3.0/build/./gcc/collect-ld" "RANLIB=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc/bin/ranlib" "NM=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/build/host-gcc-final-5.3.0/build/./gcc/nm" "NM_FOR_BUILD=" "NM_FOR_TARGET=/home/jcmvbkbc/tmp/br/build-gdb-binutils-update-dc233c/host/usr/xtensa-buildroot-linux-uclibc/bin/nm" "DESTDIR=" "WERROR=" all-recursive With --enable-cxx-flags="$(TARGET_CFLAGS)" in the HOST_GCC_FINAL_CONF_OPTS make invocation lines are the same, but makefiles in libstdc++ differ by the EXTRA_CXX_FLAGS. OTOH since flags propagation is fixed in gcc-5.x maybe backporting that fix is the right thing? -- Thanks. -- Max ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Buildroot] [PATCH] gcc/gcc-final: pass TARGET_CFLAGS flags to configure with --enable-cxx-flags 2016-03-10 9:37 ` Max Filippov @ 2016-03-10 9:46 ` Arnout Vandecappelle 2016-03-10 9:57 ` Max Filippov 0 siblings, 1 reply; 6+ messages in thread From: Arnout Vandecappelle @ 2016-03-10 9:46 UTC (permalink / raw) To: buildroot On 03/10/16 10:37, Max Filippov wrote: > Arnout, Yann, > > On Wed, Mar 9, 2016 at 2:22 AM, Arnout Vandecappelle <arnout@mind.be> wrote: >> On 01/09/16 23:08, Yann E. MORIN wrote: >>> On 2015-06-01 17:37 +0300, Max Filippov spake thusly: >>>> >>>> Currently only TARGET_ABI flags are passed to the final compiler >>>> configure script and only when building for Xtensa. Since libstdc++ is a >>>> normal library it should be built with full TARGET_CFLAGS on all >>>> targets. >>>> >>>> Pass TARGET_CFLAGS flags to gcc-final configure script for all targets >>>> in the --enable-cxx-flags parameter. >>>> >>>> Suggested-by: Arnout Vandecappelle <arnout@mind.be> >>>> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> >>> >>> >>> So, I finally had a look at this patch. I've tested it to build a >>> gcc-4.9 + glibc-2.21 + binutils-2.24 toolchain with C++ support, which >>> then was used to suessfully build Qt5base (which is quite a heavy C++ >>> user). >>> >>> However, I'd like to understand what this is all about. >>> >>> In gcc.mk, we do: >>> >>> GCC_COMMON_TARGET_CXXFLAGS = $(TARGET_CXXFLAGS) >>> [...] >>> HOST_GCC_COMMON_CONF_ENV += >>> CXXFLAGS_FOR_TARGET="$(GCC_COMMON_TARGET_CXXFLAGS)" >>> >>> So it looks like we were already passing the proper CXXFLAGS to gcc (we >>> only filter-out problematic flags, like -Os on broken gcc-4.5 for PPC). >>> >>> So, what are we supposed to gain/loose with this change? >>> >>> As a side note, we should not have to pass TARGET_ABI either, since it >>> is part of TARGET_CFLAGS and as shown above, it is already part of the >>> CFLAGS_FOR_TARGET that we pass gcc. >>> >>> Any explanations? Something that I missed? >> >> >> I checked in the gcc source and also couldn't find a reason why the >> CXXFLAGS_FOR_TARGET wouldn't work. Since you haven't replied to this, I've >> marked your patch as rejected in patchwork. If you do still fel it is >> warranted, please repost with a satisfactory explanation. > > Sorry, took me too long to answer the first mail. > > AFAICS neither gcc-4.8.x nor gcc-4.9.x propagate CXXFLAGS_FOR_TARGET > to CXXFLAGS for builds of libstdc++. gcc-5.x however does. Of course, I only checked the source of gcc-5.x :-) > Compare the following build log excerpts for libstdc++ of gcc-4.8, gcc-4.9 and > gcc-5 (I've reverted 2dcab526a97d and c44cf2cc97df before running these builds): > [snip] > With --enable-cxx-flags="$(TARGET_CFLAGS)" in the > HOST_GCC_FINAL_CONF_OPTS make invocation lines are the same, > but makefiles in libstdc++ differ by the EXTRA_CXX_FLAGS. > > OTOH since flags propagation is fixed in gcc-5.x maybe backporting > that fix is the right thing? If the backport is easy, by all means go for it. It's not as if we don't have gcc patches already :-) If the backport turns out to be difficult, I'm OK with taking your original patch (because even on gcc5 it doesn't change anything in practice). But it needs a comment mentioning this version dependency, so that the workaround can be removed when 4.9 is removed from buildroot. Regards, Arnout -- Arnout Vandecappelle arnout dot vandecappelle at essensium dot com Senior Embedded Software Architect . . . . . . +32-478-010353 (mobile) Essensium, Mind division . . . . . . . . . . . . . . http://www.mind.be G.Geenslaan 9, 3001 Leuven, Belgium . . . . . BE 872 984 063 RPR Leuven LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle GPG fingerprint: 7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Buildroot] [PATCH] gcc/gcc-final: pass TARGET_CFLAGS flags to configure with --enable-cxx-flags 2016-03-10 9:46 ` Arnout Vandecappelle @ 2016-03-10 9:57 ` Max Filippov 0 siblings, 0 replies; 6+ messages in thread From: Max Filippov @ 2016-03-10 9:57 UTC (permalink / raw) To: buildroot On Thu, Mar 10, 2016 at 12:46 PM, Arnout Vandecappelle <arnout@mind.be> wrote: > On 03/10/16 10:37, Max Filippov wrote: >> AFAICS neither gcc-4.8.x nor gcc-4.9.x propagate CXXFLAGS_FOR_TARGET >> to CXXFLAGS for builds of libstdc++. gcc-5.x however does. [...] >> OTOH since flags propagation is fixed in gcc-5.x maybe backporting >> that fix is the right thing? > > If the backport is easy, by all means go for it. It's not as if we don't > have gcc patches already :-) Ok, let me see if I can figure it out. -- Thanks. -- Max ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-03-10 9:57 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2015-06-01 14:37 [Buildroot] [PATCH] gcc/gcc-final: pass TARGET_CFLAGS flags to configure with --enable-cxx-flags Max Filippov 2016-01-09 22:08 ` Yann E. MORIN 2016-03-08 23:22 ` Arnout Vandecappelle 2016-03-10 9:37 ` Max Filippov 2016-03-10 9:46 ` Arnout Vandecappelle 2016-03-10 9:57 ` Max Filippov
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