[OpenJDK 2D-Dev] RFR: 8253795: Implementation of JEP 391: macOS/AArch64 Port [v10]

[Andrew Haley]

On Fri, 12 Feb 2021 11:42:59 GMT, Vladimir Kempik <vkempik at openjdk.org> wrote:

>> src/hotspot/os_cpu/bsd_aarch64/os_bsd_aarch64.cpp line 194:
>> 
>>> 192: // may get turned off by -fomit-frame-pointer.
>>> 193: frame os::get_sender_for_C_frame(frame* fr) {
>>> 194:   return frame(fr->link(), fr->link(), fr->sender_pc());
>> 
>> Why is it
>> 
>> return frame(fr->link(), fr->link(), fr->sender_pc());
>> 
>> and not 
>> 
>> return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
>> 
>> like in the bsd-x86 counter part?
>
> bsd_aarcb64 was based on linux_aarch64, with addition of bsd-specific things from bsd_x86
> You think  the bsd-x86 way is better here ?

There's no point copying x86. We don't have any way to know what the sender's SP was in a C frame without using unwind info. I think this is just used when trying to print the stack in a crash dump.

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PR: https://git.openjdk.java.net/jdk/pull/2200