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

[David Holmes]

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. :)

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