RFR: 8365231: Don't build gtest with /EHsc

[Thomas Stuefe]

On Fri, 15 Aug 2025 06:45:35 GMT, Julian Waters <jwaters at openjdk.org> wrote:

>>> But `-fno-exceptions` _is_ used for gcc (and probably for clang, though I've not checked). Verified by examination of ".o.cmdline" files for both libgtest and the HotSpot gtests.
>> 
>> Oh, and once again, thank you thank you thank you for the ".o.cmdline" files!
>
>> But `-fno-exceptions` _is_ used for gcc
> 
> -fno-exceptions to my knowledge is only set in TOOLCHAIN_CFLAGS_JVM and for adlc compiled for Linux. That must mean gtest uses the same flags that the regular JVM does. I was not aware of that, so that would make my previous statement incorrect.

> > I feel uncomfortable about switching off this warning. I agree with @TheShermanTanker there. Seems to me that if the compiler warns me that I should enable exceptions, I should do that instead of disabling the warning?
> 
> As Kim wrote, this seems to be about a bug in the compiler. If you include certain standard headers (`<ostream>`), the compiler will give this warning, regardless if you use any functions from the header or not, if you compile with exceptions disabled.
> 
> Our normal libjvm is compiled with exceptions disabled. It makes sense to run tests on a build that is as close as possible to the real thing, so we should compile libjvm for gtest with exceptions disabled, too.

Okay, so we switch the risk of mismatched tests (since we are compiled with a different setting than the production JVM) with the risk of strange errors should we accidentally trigger C++ exceptions in the googletest framework or in system libraries used by it.

I guess I can see the logic. Okay.

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PR Comment: https://git.openjdk.org/jdk/pull/26721#issuecomment-3191577136