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:[email protected]] Sent: Donnerstag, 13. Juli 2017 11:59 To: Baesken, Matthias <[email protected]>; '[email protected]' <[email protected]>; '[email protected]' <[email protected]> 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 > >
