1268518 - Baldr: Implement rotations

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, defect)

Description

[Benjamin Bouvier [:bbouvier] (inactive)]

Attachment: rotations.patch

Pretty straightforward.

Let's all welcome back MacroAssemblerARM::ma_ror/ma_rol from the dead (code)!

Comment 1

[Benjamin Bouvier [:bbouvier] (inactive)]

Attachment: tests.patch

This passes the rotl/rotr tests from the spec repo, but let's have four more tests on our side. I've also changed the basic-integer.js file to make it less indented + test more things (constants) in general.

Comment 2

[Benjamin Bouvier [:bbouvier] (inactive)]

Comment on attachment 8746561 [details] [diff] [review]
rotations.patch

Review of attachment 8746561 [details] [diff] [review]:
-----------------------------------------------------------------

Dan, Luke tells me you're back from pto. Welcome back!

Comment 3

[Luke Wagner [:luke]]

Comment on attachment 8746561 [details] [diff] [review]
rotations.patch

Review of attachment 8746561 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/asmjs/WasmIonCompile.cpp
@@ +2533,5 @@
> +    if (!EmitExpr(f, &input))
> +        return false;
> +
> +    MDefinition* count;
> +    if (!EmitExpr(f, &count))

May require rebase now :)

::: js/src/jit/arm/CodeGenerator-arm.cpp
@@ +979,5 @@
> +        Register creg = ToRegister(count);
> +        if (mir->isLeftRotate())
> +            masm.ma_rol(creg, input, dest);
> +        else
> +            masm.ma_ror(creg, input, dest);

The logic is almost identical here; is there a way to add rol/ror to the MacroAssembler and so the code-generator code could be shared?  You'd of course need to use the target's word size to compute the 0x1F mask above but that seems doable.

Comment 4

[Benjamin Bouvier [:bbouvier] (inactive)]

(In reply to Luke Wagner [:luke] from comment #3)
> ::: js/src/jit/arm/CodeGenerator-arm.cpp
> @@ +979,5 @@
> > +        Register creg = ToRegister(count);
> > +        if (mir->isLeftRotate())
> > +            masm.ma_rol(creg, input, dest);
> > +        else
> > +            masm.ma_ror(creg, input, dest);
> 
> The logic is almost identical here; is there a way to add rol/ror to the
> MacroAssembler and so the code-generator code could be shared?  You'd of
> course need to use the target's word size to compute the 0x1F mask above but
> that seems doable.
Yes, can do. It doesn't seem easy to share this with LRotate64 though, hence just sharing the code paths for x86-shared and arm, which already is a nice improvement. Thanks for the review!

Comment 5

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/ae19bf92ae8e
https://hg.mozilla.org/integration/mozilla-inbound/rev/217fc8589ae3

Comment 6

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/ae19bf92ae8e
https://hg.mozilla.org/mozilla-central/rev/217fc8589ae3