Hi Ian, as David already pointed out, the hotspot build is currently being converted to the configure-based build anyway. You can already test it by cloning http://hg.openjdk.java.net/build-infra/jdk9 and configuring with "--enable-new-hotspot-build" ("--disable-new-hotspot-build" is still the default). The new build is still in a very early stage (currently only the 'product' build is working) but it should give you an idea of how it will work. Actually you should get "--with-extra-cxxflags" for free in the new build system also I'm not sure it already works (and haven’t tested it yet).
Currently the work on the new build system got a little stuck because of holidays but as far as I know the plan is still to bring this into jdk9. If you have any suggestions for improvements the build-infra repo and mailing list are definitive the way to go. And if you have some good patches against build-infra I can try to help and sponsor them. Regards, Volker On Wed, Jul 22, 2015 at 1:20 AM, David Holmes <david.hol...@oracle.com> wrote: > Hi Ian, > > On 22/07/2015 3:01 AM, Ian Rogers wrote: >> >> The following (modest) patch against jdk9dev allows the top-level >> configure >> with --with-extra-cxxflags to pass options to the HotSpot build. An >> example >> would be: >> >> configure --fastdebug --with-extra-cxxflags=-std=c++11 >> >> Unless --with-extra-cxxflags is specified the option has no effect. I'd >> like to work to get this merged into jdk9dev and would appreciate any >> help. > > > Unfortunately this is not quite as simple as it appears due to the mess in > the hotspot build system regarding flags usage. Once upon a time we had > CFLAGS and CPPFLAGS but there was confusion whether CPP meant C++ or > C-pre-processor. It actually meant the latter but was mistakenly thought to > be the former (g++ args versus gcc args) and was eventually renamed to > CXXFLAGS. This results in quite a mess because we have eg: > > ./linux/makefiles/rules.make:CC_COMPILE = $(CC) $(CXXFLAGS) $(CFLAGS) > ./linux/makefiles/rules.make:CXX_COMPILE = $(CXX) $(CXXFLAGS) $(CFLAGS) > > which combines the "C" flags (which were always intended to just be the > compiler flags, which was a combined C/C++ compiler anyway) and the (now) > C++ flags (most of which are not at all C++ specific). So it will get the > EXTRA_CFLAGS and the EXTRA_CXXFLAGS on each compilation. > > Then things get worse because hotspot uses both sets of flags but the JDK > uses CXXFLAGS as the primary compiler flags. So taking cross-compilation as > an example, we set EXTRA_CFLAGS to hold the cross-compiler flags used in > hotspot, and set EXTRA_CXXFLAGS to hold the cross-compiler flags for the JDK > build. So with your proposed change we will now get the cross-compiler flags > specified twice on each command-line in the hotspot build. Whether that is > harmful I don't know - I'm just pointing out that this is far from clear cut > and would need some resources to establish that the change is indeed safe. > > This should all be resolved once the hotspot build is converted to be a full > configure-based build. And because that is in the pipeline we avoid doing > any major surgery to the (fragile) hotspot build system. > > David > ----- > > > >> Thanks, >> Ian Rogers, Google. >> >> --- >> Allow --with-extra-cxxflags to work with HotSpot. >> >> Pass down EXTRA_CXXFLAGS from gnumake's invocation or environment. >> >> diff -r fff6b54e9770 make/aix/makefiles/vm.make >> --- a/make/aix/makefiles/vm.make Thu Jul 16 19:28:37 2015 -0700 >> +++ b/make/aix/makefiles/vm.make Tue Jul 21 08:55:08 2015 -0700 >> @@ -112,6 +112,7 @@ >> # Extra flags from gnumake's invocation or environment >> CFLAGS += $(EXTRA_CFLAGS) >> LFLAGS += $(EXTRA_CFLAGS) >> +CXXFLAGS += $(EXTRA_CXXFLAGS) >> >> # Don't set excutable bit on stack segment >> # the same could be done by separate execstack command >> diff -r fff6b54e9770 make/bsd/makefiles/vm.make >> --- a/make/bsd/makefiles/vm.make Thu Jul 16 19:28:37 2015 -0700 >> +++ b/make/bsd/makefiles/vm.make Tue Jul 21 08:55:08 2015 -0700 >> @@ -114,6 +114,7 @@ >> # Extra flags from gnumake's invocation or environment >> CFLAGS += $(EXTRA_CFLAGS) >> LFLAGS += $(EXTRA_CFLAGS) >> +CXXFLAGS += $(EXTRA_CXXFLAGS) >> >> # Don't set excutable bit on stack segment >> # the same could be done by separate execstack command >> diff -r fff6b54e9770 make/linux/makefiles/vm.make >> --- a/make/linux/makefiles/vm.make Thu Jul 16 19:28:37 2015 -0700 >> +++ b/make/linux/makefiles/vm.make Tue Jul 21 08:55:08 2015 -0700 >> @@ -117,6 +117,7 @@ >> # Extra flags from gnumake's invocation or environment >> CFLAGS += $(EXTRA_CFLAGS) >> LFLAGS += $(EXTRA_CFLAGS) >> +CXXFLAGS += $(EXTRA_CXXFLAGS) >> >> # Don't set excutable bit on stack segment >> # the same could be done by separate execstack command >> diff -r fff6b54e9770 make/solaris/makefiles/vm.make >> --- a/make/solaris/makefiles/vm.make Thu Jul 16 19:28:37 2015 -0700 >> +++ b/make/solaris/makefiles/vm.make Tue Jul 21 08:55:08 2015 -0700 >> @@ -110,6 +110,7 @@ >> >> # Extra flags from gnumake's invocation or environment >> CFLAGS += $(EXTRA_CFLAGS) >> +CXXFLAGS += $(EXTRA_CXXFLAGS) >> >> # Math Library (libm.so), do not use -lm. >> # There might be two versions of libm.so on the build system: >> >
