> On May 8, 2020, at 7:12 AM, Magnus Ihse Bursie 
> <[email protected]> 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

Looks good.

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