RFR(S): 7147740: add assertions to check stack alignment on VM entry from generated code (x64)

[Vladimir Kozlov]

OK. It makes sense. I looked and all related bugs we had are for 64bit VM.

Thanks,
Vladimir

On 2/23/12 9:19 AM, Roland Westrelin wrote:
>> I asked about all x86 platforms. Why do you think it is not 16 bytes in 32bit VM. Looking on x86_32.ad we do align to
>> StackAlignmentInBytes.
>
> It is for the compiled code we generate. I don't think it's true for interpreted code. Also when we call the runtime and
> push arguments on the stack the alignment is not longer 16 bytes. And it's not true for the C++ code because the
> platform alignment constraint is weaker. So if we read SP from the runtime code then it's very unlikely to be aligned on
> 16 bytes.
>
> Maybe I should have made this clearer: the purpose of the asserts is to check that by the time we enter the runtime we
> honor the platform ABI so that code generated by the C compiler that rely on this assignment won't break.
>
> Roland.