After Simons question , I checked that the jdk10 builds still works with gcc 4.7 on linux x86_64 as well . And created a new webrev :
http://cr.openjdk.java.net/~mbaesken/webrevs/8184338.1/ - check adjusted to minimum gcc 4.7 - common/doc/building.md adjusted (the part talking about gcc versions) Best regards, Matthias -----Original Message----- From: Baesken, Matthias Sent: Freitag, 14. Juli 2017 08:36 To: 'Simon Nash' <si...@cjnash.com> Cc: Erik Joelsson <erik.joels...@oracle.com>; 'build-dev@openjdk.java.net' <build-dev@openjdk.java.net>; 'hotspot-...@openjdk.java.net' <hotspot-...@openjdk.java.net>; Zeller, Arno <arno.zel...@sap.com> Subject: RE: RFR: [XS] 8184338 : switch minimum supported gcc version to 4.8 - was : RE: jdk10 build : usage of -fno-var-tracking-assignments g++ flag in hotspot build > I am currently building JDK 9 for arm32 (hard float and soft float) using > a Linaro GCC 4.7 cross-compiler (binary download). What is the reason that > this cannot be supported for JDK 10? Hi Simon, reason was that we know gcc-4.8 works nicely because we do a lot of builds (+tests) with this compiler . For gcc 4.7 we just do not know ( but for old 4.3 / 4.4 it was obvious that the current flags do not work any more). If you are using a gcc compiler < 4.8 only a warning is reported , it does not mean that you cannot build any more. My first suggestion was : >>> ( e.g. change to minimum gcc 4.6 or gcc 4.7 supporting the flags used >>> in the build ) So if you see a benefit to test for minimum gcc 4.7 and not 4.8 I am fine with this too (Erik what do you think?). We at SAP just cannot tell that gcc 4.7 still works (because our builds do not use it). Best regards, Matthias -----Original Message----- From: Simon Nash [mailto:si...@cjnash.com] Sent: Donnerstag, 13. Juli 2017 21:56 To: Baesken, Matthias <matthias.baes...@sap.com> Cc: Erik Joelsson <erik.joels...@oracle.com>; 'build-dev@openjdk.java.net' <build-dev@openjdk.java.net>; 'hotspot-...@openjdk.java.net' <hotspot-...@openjdk.java.net>; Zeller, Arno <arno.zel...@sap.com> Subject: Re: RFR: [XS] 8184338 : switch minimum supported gcc version to 4.8 - was : RE: jdk10 build : usage of -fno-var-tracking-assignments g++ flag in hotspot build I am currently building JDK 9 for arm32 (hard float and soft float) using a Linaro GCC 4.7 cross-compiler (binary download). What is the reason that this cannot be supported for JDK 10? Best regards, Simon On 13/07/2017 14:40, Baesken, Matthias wrote: > Hi Erik, I prepared the change : > > http://cr.openjdk.java.net/~mbaesken/webrevs/8184338/ > > bug : > > https://bugs.openjdk.java.net/browse/JDK-8184338 > > Asking for review(s) ... > > > Best regards, Matthias > > > > > -----Original Message----- > From: Erik Joelsson [mailto:erik.joels...@oracle.com] > Sent: Donnerstag, 13. Juli 2017 13:34 > To: Baesken, Matthias <matthias.baes...@sap.com>; > 'build-dev@openjdk.java.net' <build-dev@openjdk.java.net>; > 'hotspot-...@openjdk.java.net' <hotspot-...@openjdk.java.net> > Subject: Re: jdk10 build : usage of -fno-var-tracking-assignments g++ flag in > hotspot build > > Hello, > > That would be the correct place. If you prepare the change and send the > review I can sponsor the push. > > /Erik > > On 2017-07-13 13:16, Baesken, Matthias wrote: >> Hi Erik, >> >>> AFAIK, the only reason we support GCC versions older than 4.9 is for you >>> guys at SAP, so if you would suggest dropping support, that would of >>> course be the simplest solution. >> for jdk10 it is fine for us to use minimum gcc 4.8 . That would be >> probably the most simple solution to avoid running into the >> "-fno-var-tracking-assignments" issue >> ( I now and then run into it when I forget to set the PATH to gcc-4.8 one >> should use for compiling on the SLES11 machine, so I pick up instead the >> default gcc 4.3.4 from the machine , >> configure works nicely and then the build fails in the middle of the HS make >> ) >> >> autoconf/toolchain.m4 >> >> TOOLCHAIN_MINIMUM_VERSION_gcc="4.8" >> >> Is there right place to adjust I think, I guess we need someone for Oracle >> to regenerate the generated-configure.sh files ? >> >> Best regards, Matthias >> >> >> >> >> -----Original Message----- >> From: Erik Joelsson [mailto:erik.joels...@oracle.com] >> Sent: Donnerstag, 13. Juli 2017 11:59 >> To: Baesken, Matthias <matthias.baes...@sap.com>; >> 'build-dev@openjdk.java.net' <build-dev@openjdk.java.net>; >> 'hotspot-...@openjdk.java.net' <hotspot-...@openjdk.java.net> >> Subject: Re: jdk10 build : usage of -fno-var-tracking-assignments g++ flag >> in hotspot build >> >> Hello Matthias, >> >> AFAIK, the only reason we support GCC versions older than 4.9 is for you >> guys at SAP, so if you would suggest dropping support, that would of >> course be the simplest solution. >> >> If you want to keep support but make the use of this flag optional, the >> preferred method is to add a test in flags.m4. We have macros defined >> for this. FLAGS_COMPILER_CHECK_ARGUMENTS or >> FLAGS_CXX_COMPILER_CHECK_ARGUMENTS would be suitable in this case. Use >> it to check if the flag is valid for the current compiler. If so, you >> can define a variable >> "CXXFLAGS_GCC_NO_VAR_TRACKING_ASSIGNMENTS=-fno-var-tracking-assignment" >> and empty otherwise, and in the makefile use this variable in the >> assignement. >> >> We want to avoid static shell expressions in the makefiles if possible >> and keep that kind of logic in configure. It's also better to explicitly >> check for features rather than versions. >> >> /Erik >> >> >> On 2017-07-13 11:21, Baesken, Matthias wrote: >>> Hello, when building jdk10 on Suse Linux 11 with default gcc/g++ 4.3.4 >>> installed, I was running into >>> compilation errors because of the missing support for g++ flag >>> -fno-var-tracking-assignments . >>> >>> It seems gcc-4.6 has the -fvar-tracking-assignments / >>> -fnovar-tracking-assignments flags , see >>> >>> https://gcc.gnu.org/onlinedocs/gcc-4.6.4/gcc/Option-Summary.html#Option-Summary >>> >>> I have no gcc-4.6 at hand but could verify that gcc-4.7 and gcc-4.8 "know" >>> the flag. >>> There are various solutions one could do to avoid the compilation error . >>> >>> >>> 1) disallow usage of old gcc versions here : >>> >>> autoconf/toolchain.m4 >>> >>> TOOLCHAIN_MINIMUM_VERSION_gcc="4.3" >>> >>> ( e.g. change to minimum gcc 4.6 or gcc 4.7 supporting the flags used >>> in the build ) >>> >>> >>> 2) remove the flag -fno-var-tracking-assignments for older gcc versions >>> here : >>> (in a similar way it was done : >>> http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/37e693211deb ) >>> >>> hotspot/make/lib/JvmOverrideFiles.gmk-32-ifeq ($(TOOLCHAIN_TYPE), gcc) >>> hotspot/make/lib/JvmOverrideFiles.gmk:33: >>> BUILD_LIBJVM_vmStructs.cpp_CXXFLAGS := -fno-var-tracking-assignments -O0 >>> hotspot/make/lib/JvmOverrideFiles.gmk:34: >>> BUILD_LIBJVM_jvmciCompilerToVM.cpp_CXXFLAGS := -fno-var-tracking-assignments >>> hotspot/make/lib/JvmOverrideFiles.gmk-35-endif >>> >>> What is your preferred solution ? >>> >>> >>> Thanks, Matthias >>> >>> >
