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LibJS: Handle argument spreading in the bytecode vm

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Hendiadyoin1 2022-09-09 16:05:40 +02:00 • committed by Linus Groh
parent ae52ae8f9f
commit 89408d5f64
2 changed files with 67 additions and 31 deletions
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25
Userland/Libraries/LibJS/Bytecode/Op.cpp
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@ -184,10 +184,11 @@ ThrowCompletionOr<void> NewArray::execute_impl(Bytecode::Interpreter& interprete
ThrowCompletionOr<void> Append::execute_impl(Bytecode::Interpreter& interpreter) const
{
// Note: This OpCode is used to construct array literals containing at least one spread element,
// Note: This OpCode is used to construct array literals and argument arrays for calls,
// containing at least one spread element,
// Iterating over such a spread element to unpack it has to be visible by
// the user courtesy of
// https://tc39.es/ecma262/#sec-runtime-semantics-arrayaccumulation
// (1) https://tc39.es/ecma262/#sec-runtime-semantics-arrayaccumulation
// SpreadElement : ... AssignmentExpression
// 1. Let spreadRef be ? Evaluation of AssignmentExpression.
// 2. Let spreadObj be ? GetValue(spreadRef).
@ -198,6 +199,26 @@ ThrowCompletionOr<void> Append::execute_impl(Bytecode::Interpreter& interpreter)
// c. Let nextValue be ? IteratorValue(next).
// d. Perform ! CreateDataPropertyOrThrow(array, ! ToString(𝔽(nextIndex)), nextValue).
// e. Set nextIndex to nextIndex + 1.
// (2) https://tc39.es/ecma262/#sec-runtime-semantics-argumentlistevaluation
// ArgumentList : ... AssignmentExpression
// 1. Let list be a new empty List.
// 2. Let spreadRef be ? Evaluation of AssignmentExpression.
// 3. Let spreadObj be ? GetValue(spreadRef).
// 4. Let iteratorRecord be ? GetIterator(spreadObj).
// 5. Repeat,
// a. Let next be ? IteratorStep(iteratorRecord).
// b. If next is false, return list.
// c. Let nextArg be ? IteratorValue(next).
// d. Append nextArg to list.
// ArgumentList : ArgumentList , ... AssignmentExpression
// 1. Let precedingArgs be ? ArgumentListEvaluation of ArgumentList.
// 2. Let spreadRef be ? Evaluation of AssignmentExpression.
// 3. Let iteratorRecord be ? GetIterator(? GetValue(spreadRef)).
// 4. Repeat,
// a. Let next be ? IteratorStep(iteratorRecord).
// b. If next is false, return precedingArgs.
// c. Let nextArg be ? IteratorValue(next).
// d. Append nextArg to precedingArgs.
auto& vm = interpreter.vm();