RFR: 8186780: clang-4.0 fastdebug assertion failure in os_linux_x86:os::verify_stack_alignment()

[David Holmes]

Hi Martin,

On 20/06/2018 3:03 AM, Martin Buchholz wrote:
> (There's surely a better fix that involves refactoring os/cpu/compiler 
> support)
> 
> 8186780: clang-4.0 fastdebug assertion failure in 
> os_linux_x86:os::verify_stack_alignment()
> http://cr.openjdk.java.net/~martin/webrevs/jdk/clang-verify_stack_alignment/
> https://bugs.openjdk.java.net/browse/JDK-8186780

I remain concerned about what it may mean for the stack pointer to not 
be aligned. I would have thought stack pointer alignment was part of the 
ABI for a CPU architecture, not something the compiler could choose at 
will? What about all the other code that uses StackAlignmentInBytes ??

That aside your fix excludes the assert when building with clang for 
linux x86 as intended. And I see that for BSD x86 (where we also use 
clang) that verify_stack_alignment is empty.

Thanks,
David