842264 - BaselineCompiler: Add SETELEM stub for typed arrays

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jan de Mooij [:jandem]]

Looking at some Emscripten benchmarks, we are currently spending most time in SETELEM VM calls.

Comment 1

[Jan de Mooij [:jandem]]

Attachment: Patch

Adds a stub which handles storing int32 and doubles values to typed arrays. With this patch we spend most time in JIT code on Emscripten-generated code.

Comment 2

[Kannan Vijayan [:djvj]]

Comment on attachment 715148 [details] [diff] [review]
Patch

Review of attachment 715148 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/ion/BaselineIC.cpp
@@ +3053,5 @@
> +    Register key = masm.extractInt32(R1, ExtractTemp1);
> +
> +    // Bounds check.
> +    masm.unboxInt32(Address(obj, TypedArray::lengthOffset()), scratchReg);
> +    masm.branch32(Assembler::BelowOrEqual, scratchReg, key, &failure);

Add jump to failure on key < 0.

Comment 3

[Jan de Mooij [:jandem]]

https://hg.mozilla.org/projects/ionmonkey/rev/fc9de695de03

(In reply to Kannan Vijayan [:djvj] from comment #2)
> Add jump to failure on key < 0.

The bounds check is unsigned, so it handles this case. See also the dense array stubs and the other JITs.