feat(ecmascript): %TypedArray%.prototype.set #744

yossydev · 2025-06-01T08:07:42Z

I think there are still a few things we can do.

ref: #145
doc: https://tc39.es/ecma262/multipage/indexed-collections.html#sec-%typedarray%.prototype.set

yossydev · 2025-06-01T08:10:21Z

tests/expectations.json

-  "built-ins/TypedArray/prototype/set/BigInt/boolean-tobigint.js": "FAIL",
-  "built-ins/TypedArray/prototype/set/BigInt/null-tobigint.js": "FAIL",
-  "built-ins/TypedArray/prototype/set/BigInt/number-tobigint.js": "FAIL",
-  "built-ins/TypedArray/prototype/set/BigInt/src-typedarray-big.js": "FAIL",
  "built-ins/TypedArray/prototype/set/BigInt/src-typedarray-not-big-throws.js": "FAIL",


Here are the reasons for the test262 failures.

internal error: entered unreachable code

thread 'main' panicked at nova_vm/src/ecmascript/types/spec/data_block.rs:683:13: internal error: entered unreachable code note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace fn from_le_value(agent: &mut Agent, value: Numeric) -> Self { let Ok(value) = BigInt::try_from(value) else { unreachable!() }; to_big_int64_big_int(agent, value).to_le() }

Uncaught exception: Error: SharedArrayBuffer not implemented (Testing with Int16Array.)

Uncaught exception: Error: SharedArrayBuffer not implemented (Testing with Int16Array.) Test result: Fail

.../ecmascript/builtins/indexed_collections/typed_array_objects/typed_array_intrinsic_object.rs

aapoalas

A bit more work to do around the GC handling here. You could also use the existing optimised TypedArray copy functions here instead of using the generic GetValueFromBuffer and SetValueFromBuffer methods.

aapoalas · 2025-06-06T09:28:13Z

nova_vm/src/ecmascript/builtins/indexed_collections/typed_array_objects/abstract_operations.rs

+/// targetOffset, reading the values from source.
+pub(crate) fn set_typed_array_from_typed_array<
+    'a,
+    TargetType: Viewable + std::fmt::Debug,


nitpick: Preferablytake out the std::fmt::Debug bounds once you don't need them for debugging anymore.

aapoalas · 2025-06-06T09:33:56Z

nova_vm/src/ecmascript/builtins/indexed_collections/typed_array_objects/abstract_operations.rs

+        ));
+    };
+    // 17. If target.[[ContentType]] is not source.[[ContentType]], throw a TypeError exception.
+    let is_type_match = has_matching_content_type::<TargetType>(target.get(agent));


issue: You should be checking source against TargetType; this is probably the reason for one of the failing tests.

Suggested change

let is_type_match = has_matching_content_type::<TargetType>(target.get(agent));

let is_type_match = has_matching_content_type::<TargetType>(source.get(agent));

aapoalas · 2025-06-06T09:35:09Z

nova_vm/src/ecmascript/builtins/indexed_collections/typed_array_objects/abstract_operations.rs

+    // 18. If IsSharedArrayBuffer(srcBuffer) is true, IsSharedArrayBuffer(targetBuffer) is true, and srcBuffer.[[ArrayBufferData]] is targetBuffer.[[ArrayBufferData]], let sameSharedArrayBuffer be true; otherwise, let sameSharedArrayBuffer be false.
+    // TODO: SharedArrayBuffer that we can even take here.
+    // 19. If SameValue(srcBuffer, targetBuffer) is true or sameSharedArrayBuffer is true, then
+    let mut src_byte_index = if same_value(agent, src_buffer, target_buffer) {


nitpick: I think you can just compare src_buffer == target_buffer directly; SameValue(objA, objB) is equal to objA == objB.

aapoalas · 2025-06-06T09:36:57Z

nova_vm/src/ecmascript/builtins/indexed_collections/typed_array_objects/abstract_operations.rs

+            src_byte_length,
+            gc.nogc(),
+        )
+        .unbind()?;


issue: You need to rebind here since the resulting cloned src_buffer needs to be tracked by the GC:

Suggested change

.unbind()?;

.unbind()?.bind(gc.nogc());

aapoalas · 2025-06-06T09:41:12Z

nova_vm/src/ecmascript/builtins/indexed_collections/typed_array_objects/abstract_operations.rs

+    if core::any::TypeId::of::<SrcType>() == core::any::TypeId::of::<TargetType>() {
+        // a. NOTE: The transfer must be performed in a manner that preserves the bit-level encoding of the source data.
+        // Repeat, while targetByteIndex < limit,
+        while target_byte_index < limit {


issue: Here we want to use the methods you've already added to dealing with copying data from one TypedArray to another, that just perform copy_from_slice from &[SrcType: Viewable] to &mut [TargetType: Viewable].

aapoalas · 2025-06-06T10:03:13Z

.../ecmascript/builtins/indexed_collections/typed_array_objects/typed_array_intrinsic_object.rs

+                    scoped_o.get(agent),
+                    target_offset,
+                    scoped_source.get(agent),
+                    gc.reborrow()


nitpick: You could just pass in gc directly to all the SetTypedArrayFrom... calls, which would mean you don't need to .unbind()? the result but can just use ? directly.

aapoalas · 2025-06-06T10:03:48Z

.../ecmascript/builtins/indexed_collections/typed_array_objects/typed_array_intrinsic_object.rs

+                    scoped_o.get(agent),
+                    target_offset,
+                    source,
+                    gc.reborrow()


Suggested change

gc.reborrow()

gc

aapoalas · 2025-06-06T10:04:02Z

.../ecmascript/builtins/indexed_collections/typed_array_objects/typed_array_intrinsic_object.rs

+                ),
+                V
+            )
+            .unbind()?;


Suggested change

.unbind()?;

?;

aapoalas · 2025-06-06T10:05:25Z

.../ecmascript/builtins/indexed_collections/typed_array_objects/typed_array_intrinsic_object.rs

+                scoped_o.get(agent),
+                set_typed_array_from_array_like::<T>(
+                    agent,
+                    scoped_o.get(agent),


issue: Since you already have scoped_o as Scoped, it doesn't make sense to get its result and then immediately scope it again inside the SetTypedArrayFromX calls: Just pass the Scoped<TypedArray> directly instead, and that'll save you one unnecessary scoping.

aapoalas · 2025-06-06T10:06:44Z

.../ecmascript/builtins/indexed_collections/typed_array_objects/typed_array_intrinsic_object.rs

+                    agent,
+                    scoped_o.get(agent),
+                    target_offset,
+                    scoped_source.get(agent),


issue: Here too, you can just pass in the scoped_source: Scoped<Value> directly; inside the call you'll need to do let src = source.replace_self(agent, src); after you've done let src = to_object(agent, source.get(agent), gc.nogc()); but otherwise it should be all good.

…m_slice

…copy_from_slice" This reverts commit 7877d47.

yossydev · 2025-06-13T15:32:15Z

I’m still investigating just that one: #744 (comment)

yossydev commented Jun 1, 2025

View reviewed changes

yossydev changed the title ~~feat: %TypedArray%.prototype.set~~ feat(ecmascript): %TypedArray%.prototype.set Jun 1, 2025

yossydev marked this pull request as ready for review June 1, 2025 09:12

aapoalas requested changes Jun 6, 2025

View reviewed changes

yossydev added 11 commits June 12, 2025 10:33

feat(ecmascript): %TypedArray%.prototype.set

5424a2a

chore(ecmascript): update expectations

f6d9b71

chore(ecmascript): update metrics

8aa13bf

chore(ecmascript): target and source are sameType then, used copy_fro…

9dc3995

…m_slice

Revert "chore(ecmascript): target and source are sameType then, used …

852a68c

…copy_from_slice" This reverts commit 7877d47.

chore(ecmascript): update expectations and metrics

6f424e8

chore(ecmascript): remove std::fmt::Debug

9e3bc21

chore(ecmascript): source against TargetType

e76cbd5

chore(ecmascript): compare src_buffer == target_buffer

b8dfd41

chore(ecmascript) fix review

83e0267

chore(ecmascript): update metrics

3967d8d

yossydev force-pushed the feat/typedarray-prototype-set branch from cae79d9 to 3967d8d Compare June 13, 2025 14:02

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yossydev commented Jun 13, 2025

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	let is_type_match = has_matching_content_type::<TargetType>(target.get(agent));
	let is_type_match = has_matching_content_type::<TargetType>(source.get(agent));

feat(ecmascript): %TypedArray%.prototype.set #744

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yossydev commented Jun 1, 2025

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internal error: entered unreachable code

Uncaught exception: Error: SharedArrayBuffer not implemented (Testing with Int16Array.)

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yossydev commented Jun 13, 2025

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