On Mon, Jul 11, 2016 at 4:29 AM, Patrick Ohly <[email protected]> wrote: > Dan McGregor <danismostlikely <at> gmail.com> writes: >> From: Daniel McGregor <daniel.mcgregor <at> vecima.com> >> >> GCC 6 sets the default C++ standard to C++14 and introduces dead store >> elimination by default. OpenJDK 8 is not ready for either of these >> changes, so set the C++ standard back to gnu++98 and disable dead >> store elimination. >> >> Switched to using --with-extra-cflags, cxxflags, and ldflags. The added >> patch fixes building when using those flags, and are needed to get >> CFLAGS into the JDK build in the native case. > > Has anyone tested this on a host system where gcc is still 4.x, like 4.9.2 > on Debian Wheezy? > > I'm finding that -fno-lifetime-dse is also getting passed to the gcc used > for compiling native binaries (obviously in openjdk-8-native, but also for > some helper executables in openjdk-8). This then breaks the compilation > because older gcc rejects that flag. > > I've briefly toyed with the patch below which worked for openjdk-8-native, > but not for openjdk-8. I'm just going to work around it by staying on gcc > 5.x and clearing these extra flags. > > I'm not familiar enough with the openjdk-8 build process to propose a better > solution, but perhaps someone else has an idea? > > diff --git a/meta-java/recipes-core/openjdk/openjdk-8-common.inc > b/meta-java/recipes-core/openjdk/openjdk-8-common.inc > index dd3d397..060d828 100644 > --- a/meta-java/recipes-core/openjdk/openjdk-8-common.inc > +++ b/meta-java/recipes-core/openjdk/openjdk-8-common.inc > @@ -237,6 +237,25 @@ EXTRA_OECONF_append = "\ > --with-update-version=${OPENJDK_UPDATE_VERSION} \ > " > > -CFLAGS_append = " -fno-lifetime-dse -fno-delete-null-pointer-checks" > -CXXFLAGS_append = " -fno-lifetime-dse -fno-delete-null-pointer-checks" > +# GCC 6 sets the default C++ standard to C++14 and introduces dead store > +# elimination by default. OpenJDK 8 is not ready for either of these > +# changes. > +FLAGS_GCC6 = "-fno-lifetime-dse -fno-delete-null-pointer-checks" > + > +# All supported cross compilers support the compiler flags that were > +# added to make compilation with gcc6 work. But the host compiler for > +# native compilation is a different story: it may be too old (for example, > +# gcc 4.9.2 on Debian Wheezy). In that case we need to check what the > +# version is and unset the flags when gcc is not yet GCC 6. > +python () { > + if d.getVar('PN', True).endswith('-native'): > + import re, subprocess > + version = subprocess.check_output(d.expand('${CC} > --version').split()).decode('utf-8') > + m = re.search(r'^gcc.* (\d+)(\.\d+)*$', version, re.MULTILINE) > + if m and int(m.group(1)) < 6: > + d.setVar('FLAGS_GCC6', '') > +} > + > +CFLAGS_append = " ${FLAGS_GCC6}" > +CXXFLAGS_append = " ${FLAGS_GCC6}" > CXX_append = " -std=gnu++98"
I can see this needed in several other cases too. May be this should be made a common utility > > Bye, Patrick > > -- > _______________________________________________ > Openembedded-devel mailing list > [email protected] > http://lists.openembedded.org/mailman/listinfo/openembedded-devel -- _______________________________________________ Openembedded-devel mailing list [email protected] http://lists.openembedded.org/mailman/listinfo/openembedded-devel
