1711839 - Make ARM simulator work on M1 mac and other arm64 systems

Status: NEW

(Core :: JavaScript Engine: JIT, enhancement, P3)

Description

[Lars T Hansen [:lth]]

Increasingly development will be done on non-x64 systems as we move to new Mac laptops. At the moment, the ARM simulator is blocked from working on the M1 mac by a line in moz.configure, but getting past that I see a lot of compilation errors (which may or may not be unrelated; investigating). We should fix this, as the ARM simulator is useful for ARM development and as there seems to be no good reason why it can't work on ARM64.

Comment 1

[Lars T Hansen [:lth]]

I guess the trick about the ARM simulator is that it only works on 32-bit x86 (another platform that is looking a little long in the tooth), so the compilation errors may be related to ARM64 being, well, 64-bit. Fixing that mismatch may be hard, as the C++ parts of the runtime will depend on the word size of the platform for its layouts (64 bits) while the jitted code would depend on the words size of the simulated CPU (32 bits).

This doesn't make the problem of not having an ARM simulator go away, though. However, x86 code hasn't been supported on the x64 Mac laptops for some time, so ARM development hasn't been able to happen on Macs for a while already. So maybe this is not a huge concern.