RFR: JDK-8155587: Cross compilation may cause compiler warnings for "build" compiler

[Erik Joelsson]

On 2016-05-11 08:05, David Holmes wrote:
> Hi Erik,
>
> Seems reasonable. flags.m4 is okay, but the toolchain.m4 changes 
> stretch my comprehension of the overall process. As long as this gets 
> through jprt with -testset hotspot, then I'm fine with it. :)
>
I agree this got nasty. I was actually surprised that I managed to solve 
it as quickly as I did. I have run a successful hotspot job with it.

Thanks for reviews, David and Chris.

/Erik
> Thanks,
> David
>
> On 11/05/2016 2:41 AM, Erik Joelsson wrote:
>> Hello,
>>
>> When cross compiling, we compile a subset of the jdk for the build host
>> to be able to run jmod and jlink. Configure sets up a toolchain for this
>> through variables prefixed "BUILD_" (BUILD_CC etc). The new nifty macro
>> we have for conditionally setting compiler flags depending on the
>> version of the compiler is currently unaware of this. The result is that
>> if the compiler version for the target and build toolchain differ, the
>> macro will provide the wrong compiler flags.
>>
>> This patch makes the version check macro able to handle both the target
>> and build toolchain. It also fixes the BUILD_CC_DISABLE_WARNING_PREFIX
>> variable which is currently always empty. The result is that our cross
>> compile configurations at Oracle no longer emits warnings from the build
>> toolchain.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8155587
>> Webrev: http://cr.openjdk.java.net/~erikj/8155587/webrev.top.01/
>>
>> /Erik