Previously the ARM64 JIT didn't support cache clearing at all.
This adds support for clearing the JIT cache while keeping dispatcher
helpers around and the ASM dispatcher alive.
Improves compilation time by multiple minutes
Clang was taking multiple minutes to compile JIT.cpp for ARM.
This drops it down to a handful of seconds instead.
No functional behaviour change, only movement.
JIT compile times might deviate slightly moving from a switch to a jump
table, but will be negligible in either direction.
This was spending ~60seconds of time compiling on my c630.
Something about fmt string formatting causing heavy compile times on
ARM.
Better to just compile it out anyway.
The break ir op is actually a block ender and it happened that in
regular code paths they were already ending the blocks correctly.
This enforces block ending in the Unimplemented op so multiblock still
generates the invalid code path correctly and it compiles.
We hit these a few times in multiblock for times in the code where it is
checking for CPU features and choosing a code path depending on CPUID
results.
Potentially these could be made in to no-ops since we'll never hit these
codepaths in practice, but it is nicer to break in case we actually do
hit one of these paths.
There's some history for this instruction. It is not in the official
instruction documentations from AMD or Intel but it is supported on
almost every x87 supporting CPU (I think there was some Cyrix that
missed it?)
This was originally implemented by accident on the Intel 80287 CPU.
It was then periodically documented in random documentation.
The instruction behaves exactly like FFREE but then pops the stack after
the operation.
For our current implementation of FFREE, which is a NOP, we just need to
pop the stack.
This must of have been a copy and paste error, I didn't even have this
instruction on my list of implemented instructions.
It definitely isn't converting to a GPR
32bit apps are setting GS register that I saw.
64Bit applications can also technically use these instructions but it
has some major limitation that causes applications to never use them
These can only be implemented as acquire/release exclusive loops on
ARMv8.0 so they end up looking pretty disgusting.
This is more for compatibility for testing than anything. I'm not
expecting ANY ARMv8.0 device to get decent performance
