From my point of view, the minimum version is a bit arbitrary. We have
identified that we likely need 4.6 or newer now, so we could set the
limit to 4.6 or 4.7 if needed. Supporting very old compilers have a
cost. The setting here will only cause a warning to be printed that
essentially means we don't test builds with this old compiler and we
won't make any effort in keeping it working. I would expect 4.7 to
continue to work for a time anyway.
Eventually though, we will upgrade the recommended toolchain and we will
start using newer compiler features that will make older compilers
obsolete for real.
/Erik
On 2017-07-13 21:56, Simon Nash wrote:
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
