On Mon, 26 Apr 2021 12:52:54 GMT, Jorn Vernee <jver...@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 > > Hi Nick. Sorry for the late reply, I've been out sick. I'll hopefully be > taking a thorough look at this soon (still catching up on things). > > I'm pretty impressed that such a large amount of code can just be shared > between the two platforms :) @JornVernee thanks for the review. I'll park this until the JEP is integrated and then fix it up afterwards. ------------- PR: https://git.openjdk.java.net/jdk/pull/3617
