RFR: 8263512: [macos_aarch64] issues with calling va_args functions from invoke_native [v2]

[Nick Gasson]

On Thu, 3 Jun 2021 03:09:58 GMT, Nick Gasson <ngasson at openjdk.org> wrote:

>> macOS on Apple silicon uses slightly different ABI conventions to the
>> standard AArch64 ABI.  The differences are outlined in [1].  In
>> particular in the standard (AAPCS) ABI, variadic arguments may be passed
>> in either registers or on the stack following the normal calling
>> convention.  To handle this, va_list is a struct containing separate
>> pointers for arguments located in integer registers, floating point
>> registers, and on the stack.  Apple's ABI simplifies this by passing all
>> variadic arguments on the stack and the va_list type becomes a simple
>> char* pointer.
>> 
>> This patch adds a new MacOsAArch64 CABI type and MacOsAArch64Linker to
>> represent the new ABI variant on macOS.  StackVaList is based on
>> WinVaList lightly modified to handle the different TypeClasses on
>> AArch64.  The original AArch64Linker is renamed to AapcsLinker and is
>> currently used for all non-Mac platforms.  I think we also need to add a
>> WinAArch64 CABI but I haven't yet been able to test on a Windows system
>> so will do that later.
>> 
>> The macOS ABI also uses a different method of spilling arguments to the
>> stack (the standard ABI pads each argument to a multiple of 8 byte stack
>> slots, but the Mac ABI packs arguments according to their natural
>> alignment).  None of the existing tests exercise this so I'll open a new
>> JBS issue and work on that separately.
>> 
>> Tested jdk_foreign on macOS AArch64, Linux AArch64, and Linux X86_64.
>> 
>> [1] https://developer.apple.com/documentation/xcode/writing_arm64_code_for_apple_platforms
>
> Nick Gasson has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:
> 
>  - Fixes after JEP integratioN
>    
>    Change-Id: Iaa13b3869522c8814c3f7ef4c1eac8e8267657e6
>    CustomizedGitHooks: yes
>  - merge master
>    
>    Change-Id: Ic06fec084099ff2053dd251a255cbbf4a64a59d7
>    CustomizedGitHooks: yes
>  - 8263512: [macos_aarch64] issues with calling va_args functions from invoke_native
>    
>    macOS on Apple silicon uses slightly different ABI conventions to the
>    standard AArch64 ABI.  The differences are outlined in [1].  In
>    particular in the standard (AAPCS) ABI, variadic arguments may be passed
>    in either registers or on the stack following the normal calling
>    convention.  To handle this, va_list is a struct containing separate
>    pointers for arguments located in integer registers, floating point
>    registers, and on the stack.  Apple's ABI simplifies this by passing all
>    variadic arguments on the stack and the va_list type becomes a simple
>    char* pointer.
>    
>    This patch adds a new MacOsAArch64 CABI type and MacOsAArch64Linker to
>    represent the new ABI variant on macOS.  StackVaList is based on
>    WinVaList lightly modified to handle the different TypeClasses on
>    AArch64.  The original AArch64Linker is renamed to AapcsLinker and is
>    currently used for all non-Mac platforms.  I think we also need to add a
>    WinAArch64 CABI but I haven't yet been able to test on a Windows system
>    so will do that later.
>    
>    The macOS ABI also uses a different method of spilling arguments to the
>    stack (the standard ABI pads each argument to a multiple of 8 byte stack
>    slots, but the Mac ABI packs arguments according to their natural
>    alignment).  None of the existing tests exercise this so I'll open a new
>    JBS issue and work on that separately.
>    
>    Tested jdk_foreign on macOS AArch64, Linux AArch64, and Linux X86_64.

I've rebased this on the latest master after the JEP integration and fixed the issues above. Should be good to re-review. I've done the suggested renaming to LinuxAArch64Linker, MacOsAArch64Linker, etc.

-------------

PR: https://git.openjdk.java.net/jdk/pull/3617