diff --git a/Userland/Libraries/LibJS/Runtime/Value.cpp b/Userland/Libraries/LibJS/Runtime/Value.cpp index 19b517917f..450c6a3d80 100644 --- a/Userland/Libraries/LibJS/Runtime/Value.cpp +++ b/Userland/Libraries/LibJS/Runtime/Value.cpp @@ -1496,19 +1496,42 @@ ThrowCompletionOr unary_minus(VM& vm, Value lhs) } // 13.9.1 The Left Shift Operator ( << ), https://tc39.es/ecma262/#sec-left-shift-operator +// ShiftExpression : ShiftExpression << AdditiveExpression ThrowCompletionOr left_shift(VM& vm, Value lhs, Value rhs) { + // 13.15.3 ApplyStringOrNumericBinaryOperator ( lval, opText, rval ), https://tc39.es/ecma262/#sec-applystringornumericbinaryoperator + // 1-2, 6. N/A. + + // 3. Let lnum be ? ToNumeric(lval). auto lhs_numeric = TRY(lhs.to_numeric(vm)); + + // 4. Let rnum be ? ToNumeric(rval). auto rhs_numeric = TRY(rhs.to_numeric(vm)); + + // 7. Let operation be the abstract operation associated with opText and Type(lnum) in the following table: + // [...] + // 8. Return operation(lnum, rnum). if (both_number(lhs_numeric, rhs_numeric)) { + // 6.1.6.1.9 Number::leftShift ( x, y ), https://tc39.es/ecma262/#sec-numeric-types-number-leftShift + + // OPTIMIZATION: Handle infinite values according to the results returned by ToInt32/ToUint32. if (!lhs_numeric.is_finite_number()) return Value(0); if (!rhs_numeric.is_finite_number()) return lhs_numeric; - // Ok, so this performs toNumber() again but that "can't" throw + + // 1. Let lnum be ! ToInt32(x). auto lhs_i32 = MUST(lhs_numeric.to_i32(vm)); - auto rhs_u32 = MUST(rhs_numeric.to_u32(vm)) % 32; - return Value(lhs_i32 << rhs_u32); + + // 2. Let rnum be ! ToUint32(y). + auto rhs_u32 = MUST(rhs_numeric.to_u32(vm)); + + // 3. Let shiftCount be ℝ(rnum) modulo 32. + auto shift_count = rhs_u32 % 32; + + // 4. Return the result of left shifting lnum by shiftCount bits. The mathematical value of the result is + // exactly representable as a 32-bit two's complement bit string. + return Value(lhs_i32 << shift_count); } if (both_bigint(lhs_numeric, rhs_numeric)) { // 6.1.6.2.9 BigInt::leftShift ( x, y ), https://tc39.es/ecma262/#sec-numeric-types-bigint-leftShift @@ -1530,6 +1553,8 @@ ThrowCompletionOr left_shift(VM& vm, Value lhs, Value rhs) // 2. Return the BigInt value that represents ℝ(x) × 2^y. return Value(BigInt::create(vm, lhs_numeric.as_bigint().big_integer().multiplied_by(multiplier_divisor))); } + + // 5. If Type(lnum) is different from Type(rnum), throw a TypeError exception. return vm.throw_completion(ErrorType::BigIntBadOperatorOtherType, "left-shift"); }