RFR(S): 8043491: warning LNK4197: export '... ...' specified multiple times; using first specification

[Christian Tornqvist]

Hi Calvin,

Change looks good, thanks for fixing this.

Thanks,
Christian

-----Original Message-----
From: hotspot-runtime-dev
[mailto:hotspot-runtime-dev-bounces at openjdk.java.net] On Behalf Of Calvin
Cheung
Sent: Tuesday, November 11, 2014 1:13 AM
To: hotspot-runtime-dev at openjdk.java.net
Subject: RFR(S): 8043491: warning LNK4197: export '... ...' specified
multiple times; using first specification

This is for fixing link warnings on windows such as the following:
jni.obj : warning LNK4197: export 'JNI_CreateJavaVM' specified multiple
times; using first specification

The warning is reproducible with both VS2010 and VS2013.
It is applicable to 64-bit only probably due to the
__declspec(dllexport) on 32-bit, it exports the function decorated name with
a leading underscore, but not the case on 64-bit as described in:
http://stackoverflow.com/questions/3572344/a-warning-with-building-64bit-dll

All those functions are declared with JNIEXPORT (#define JNIEXPORT
__declspec(dllexport)) and we're adding the /export:<function name> in the
link command. Therefore, on 64-bit platform, we get the "specified multiple
times" LNK4197 warning.

A fix is to check if the platform is 64-bit, we don't add those /export
option to the link command.

JBS: https://bugs.openjdk.java.net/browse/JDK-8043491

webrev: http://cr.openjdk.java.net/~ccheung/8043491/webrev/

Tests:
     (1) build jvm.dll via command line (both 32- and 64-bit)
           use configure.sh to setup and then do "make CONF=<config>
hotspot"

     (2) generate visual studio project files using ProjectCreator (both
32- and 64-bit)
           build jvm.dll via VS2013 (both 32- and 64-bit)

     (3) JPRT

thanks,
Calvin