What to do: clang-4.0 fastdebug assertion failure in os_linux_x86:os::verify_stack_alignment()

[Martin Buchholz]

There's only one remaining problem building latest jdk with latest clang on
Linux preventing it from working out of the box.  It seems likely macosx
has the same problem.

https://bugs.openjdk.java.net/browse/JDK-8186780
clang-4.0 fastdebug assertion failure in
os_linux_x86:os::verify_stack_alignment()

Verifying stack alignment seems rather fragile, especially in the presence
of inlining.

There are various things we can do:
- making os::verify_stack_alignment NOINLINE and/or moving
os::verify_stack_alignment
to its own translation unit.
- simply disabling the stack alignment check for clang
- I don't see any reason why esp should be aligned even if stack frames
are.  (Maybe ebp is better?  I'm not a x86 assembly programmer) More
principled seems invoking functions recursively and disabling inlining and
checking that the difference between addresses of a local is a multiple of
the alignment, but that will get complicated.
- why does stack alignment even matter? Isn't it the alignment of c++
objects on the stack that matter?