RFR: JDK-8244653 Suppress gcc 9.1 ABI change notes on aarch64

[Erik Joelsson]

Looks good.

/Erik

On 2020-05-08 04:12, Magnus Ihse Bursie wrote:
> When building HotSpot with gcc9.x for aarch64, there are a couple of 
> places that trigger a "warning" (technically a "note") about an ABI 
> change from earlier versions.  The message is
>
> <location>: note: parameter passing for argument of type '<type> 
> changed in GCC 9.1
>
> This is mentioned prominently in the gcc 9 release notes:
>
> "On Arm targets (arm*-*-*), a bug in the implementation of the 
> procedure call standard (AAPCS) in the GCC 6, 7 and 8 releases has 
> been fixed: a structure containing a bit-field based on a 64-bit 
> integral type and where no other element in a structure required 
> 64-bit alignment could be passed incorrectly to functions. This is an 
> ABI change. If the option -Wpsabi is enabled (on by default) the 
> compiler will emit a diagnostic note for code that might be affected."
>
> As the only HotSpot types being warned about are internal and do not 
> cross library boundaries, and we compile the entire jdk with the same 
> compiler, these "warnings" are not interesting and just clutter build 
> logs and cause unnecessary worry.
>
> To suppress these notes, -Wno-psabi should be added to the compiler 
> options for HotSpot when building for any flavor of ARM, i.e. when the 
> $VAR_CPU build variable is "arm" or "aarch64". That option is already 
> present for "arm" because of a similar issue with gcc 4.4. We should 
> add it for "aarch64".
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8244653
> WebRev: 
> http://cr.openjdk.java.net/~ihse/JDK-8244653-no-psabi-for-aarch64/webrev.01
>
> /Magnus