1436955 - Make ARM64 simulator support wasm

Status: RESOLVED FIXED

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

Description

[Lars T Hansen [:lth]]

The parts needed for wasm are support for illegal-instruction and out-of-bounds faults, and a couple of new callouts.  There's also a bug that needs fixing.

Comment 1

[Lars T Hansen [:lth]]

Attachment: bug1436955-arm64-simulator-fixes.patch

See commit msg for most details; nothing here should be surprising.  The one thing worth noting is that I have not fixed the SIMD memory accesses for OOB faults because they take a different path; I'm not in the mood to do the reengineering of that now since we still won't support asm.js on the platform and wasm does not yet have SIMD.

Comment 2

[Benjamin Bouvier [:bbouvier] (inactive)]

Comment on attachment 8949659 [details] [diff] [review]
bug1436955-arm64-simulator-fixes.patch

Review of attachment 8949659 [details] [diff] [review]:
-----------------------------------------------------------------

Pretty mechanic. Thanks!

::: js/src/jit/arm64/vixl/MozSimulator-vixl.cpp
@@ +274,2 @@
>    if (!fp)
>        return;

This can be removed, now that the jit->wasm patch has landed...

@@ +280,2 @@
>  
> +  startWasmInterrupt(act, pc, fp);

... and this now returns bool, thus needs testing.

@@ +285,5 @@
> +bool
> +Simulator::handle_wasm_seg_fault(uintptr_t addr, unsigned numBytes)
> +{
> +    uint8_t* pc = (uint8_t*)get_pc();
> +    uint8_t* fp = (uint8_t*)xreg(29);

a get_fp() method would be nice, to avoid remembering what's the register number each time? (and would have prevented the error you fixed above)

@@ +301,5 @@
> +        return false;
> +
> +    const js::wasm::MemoryAccess* memoryAccess = instance->code().lookupMemoryAccess(pc);
> +    if (!memoryAccess) {
> +        startWasmInterrupt(act, pc, fp);

MOZ_ALWAYS_TRUE

::: js/src/jit/arm64/vixl/Simulator-vixl.cpp
@@ +1027,5 @@
> +    return dummy;
> +}
> +
> +template<typename T> T
> +Simulator::Read(uintptr_t address_)

nit: is the trailing underscore needed? otherwise might be nice to just get rid of it?

@@ +1036,5 @@
> +    return Memory::Read<T>(address_);
> +}
> +
> +template <typename T> void
> +Simulator::Write(uintptr_t address_, T value)

ditto

Comment 3

[Lars T Hansen [:lth]]

Attachment: bug1436955-arm64-simulator-fixes-v2.patch

Rebased, picked up a few bug fixes & changes to ARM simulator, ready to land.  Carrying r+.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/b24d7a6d720a
ARM64 Simulator, bugfixes and wasm support. r=bbouvier

Comment 5

[Tiberius Oros[:tiberius_oros]]

https://hg.mozilla.org/mozilla-central/rev/b24d7a6d720a