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. ------------- Commit messages: - 8263512: [macos_aarch64] issues with calling va_args functions from invoke_native Changes: https://git.openjdk.java.net/jdk/pull/3617/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3617&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8263512 Stats: 770 lines in 12 files changed: 568 ins; 112 del; 90 mod Patch: https://git.openjdk.java.net/jdk/pull/3617.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/3617/head:pull/3617 PR: https://git.openjdk.java.net/jdk/pull/3617
