Small problem compiling Loom with GCC 10.1.0

[Alan Bateman]

On 02/06/2020 13:51, Mark Raynsford wrote:
> Hello!
>
> I see the following with the latest fibers branch:
>
> * For target support_native_java.base_libfdlibm_k_standard.o:
> /home/rm/git/com.github/openjdk/loom/src/java.base/share/native/libfdlibm/k_standard.c: In function '__j__kernel_standard':
> /home/rm/git/com.github/openjdk/loom/src/java.base/share/native/libfdlibm/k_standard.c:743:19: error: 'exc.retval' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>    743 |         return exc.retval;
>        |                ~~~^~~~~~~
> cc1: all warnings being treated as errors
>
> It's not wrong. If the function is passed some "type" value outside
> of the range [1,42], the function will return whatever happened to be
> on the stack in exc.retval. Perhaps adding an assertion would make
> sense here?
I assume you'll see the same thing if you try to build the main line 
(openjdk/jdk on github, jdk/jdk on hg). JDK-8234362 [1] may be the same 
issue. So I don't think this is anything specific to the loom repo and 
we should probably try to get it fixed in the main line to help those 
that build with gcc 10 or 10.1.

-Alan.

[1] https://bugs.openjdk.java.net/browse/JDK-8234362