RFR: 8342869: Errors related to unused code on Windows after 8339120 in awt

[Julian Waters]

On Thu, 24 Oct 2024 22:07:52 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> After 8339120, gcc began catching many different instances of unused code in the Windows specific codebase. Some of these seem to be bugs. I've taken the effort to mark out all the relevant globals and locals that trigger the unused warnings and addressed all of them by commenting out the code as appropriate. I am confident that in many cases this simplistic approach of commenting out code does not fix the underlying issue, and the warning actually found a bug that should be fixed. In these instances, I will be aiming to fix these bugs with help from reviewers, so I recommend anyone reviewing who knows more about the code than I do to see whether there is indeed a bug that needs fixing in a different way than what I did
>
> make/autoconf/flags-cflags.m4 line 589:
> 
>> 587:   # CXXFLAGS C++ language level for all of JDK, including Hotspot.
>> 588:   if test "x$TOOLCHAIN_TYPE" = xgcc || test "x$TOOLCHAIN_TYPE" = xclang; then
>> 589:     LANGSTD_CXXFLAGS="-std=c++14"
> 
> Is this really an intention on your part, to bump the C++ level inside a PR to remove unused code? 😕 Or is it a merge error from a different PR?

It's a checkout error from the original gigantic Pull Request, sorry. I don't plan to raise the JDK to C++17 in this one. But I'm not sure what to do with this now, since maybe_unused is C++17. I don't think anyone is going to appreciate [[gnu::unused]] inside Windows code

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PR Review Comment: https://git.openjdk.org/jdk/pull/21655#discussion_r1815989407