Hi Nevill,
Just realized this was sent to hotspot-dev (attempting bcc) but is not a
hotspot issue. With your new approach this is a build issue so cc'ing
build-dev.
The new approach seems better to me but build folk need to confirm the
placement.
Thanks,
David
On 29/04/2015 8:52 PM, Edward Nevill wrote:
On Fri, 2015-04-24 at 17:11 +1000, David Holmes wrote:
Hi Ed,
On 21/04/2015 7:16 PM, Edward Nevill wrote:
Hi,
The current jdk9 tip fails to build from source on aarch64 with the following
error message
/home/ed/build/1504/dev/build/linux-aarch64-normal-server-release/support/native/java.desktop/libsplashscreen/pngrutil.o:
In function `png_init_filter_functions':
/home/ed/build/1504/dev/jdk/src/java.desktop/share/native/libsplashscreen/libpng/pngrutil.c:3947:
undefined reference to `png_init_filter_functions_neon'
collect2: error: ld returned 1 exit status
The following webrev gets it building again.
http://cr.openjdk.java.net/~enevill/8078245/webrev.00/
Shouldn't the guard be Aarch64 specific rather than just __arm__ ? I'm
also wondering how we would get __ARM_NEON defined but not __arm__?
On arm 32 bit gcc defines the symbol __ARM_NEON if the flag -mfpu=neon is
specified. Since this is not specified as part of the OpenJDK build the symbol
is not defined and the build succeeds.
On aarch64 the symbol __ARM_NEON is always defined (the theory being that
aarch64 always supports Neon). Personally I think this is borken as it causes
builds to fail (and not just OpenJDK, several other projects have had the same
build failure - try googling the above error message). But we are stuck with
gcc as it is.
However, I don't like the above fix because it not only modifies the jdk, it
modifies an external component which is pulled into jdk, which means every time
a new revision of linpng is pulled in, the patch will have to be applied again.
A better approach I think is to define the symbol PNG_ARM_NEON_OPT=0 in the
build (only if aarch64).
The failing code in pngpriv.h reads
#ifndef PNG_ARM_NEON_OPT
...
# if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
defined(PNG_ALIGNED_MEMORY_SUPPORTED)
# define PNG_ARM_NEON_OPT 2
# else
# define PNG_ARM_NEON_OPT 0
# endif
#endif
So, if we just predefine PNG_ARM_NEON=0 in the build this will have the same
effect as adding defined(__arm__) or !defined(__aarch64__) above.
The following patch webrev does this:-
http://cr.openjdk.java.net/~enevill/8078245/webrev.01/
If you are happy with this and if I could have another reviewer I will push
this.
All the best,
Ed.
