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LibJS: Improve correctness of rounding and bitwise operations

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Patch from Anonymous
This commit is contained in:
Andreas Kling 2021-02-05 09:11:58 +01:00
parent 6622ad8895
commit 16a0e7a66d
9 changed files with 106 additions and 19 deletions
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11
Userland/Libraries/LibJS/Runtime/MathObject.cpp
View file

@ -154,7 +154,16 @@ JS_DEFINE_NATIVE_FUNCTION(MathObject::round)
return {};
if (number.is_nan())
return js_nan();
return Value(::round(number.as_double()));
double intpart = 0;
double frac = modf(number.as_double(), &intpart);
if (intpart >= 0) {
if (frac >= 0.5)
intpart += 1.0;
} else {
if (frac < -0.5)
intpart -= 1.0;
}
return Value(intpart);
}
JS_DEFINE_NATIVE_FUNCTION(MathObject::max)

63
Userland/Libraries/LibJS/Runtime/Value.cpp
View file

@ -465,6 +465,7 @@ BigInt* Value::to_bigint(GlobalObject& global_object) const
}
}
// FIXME: These two conversions are wrong for JS, and seem likely to be footguns
i32 Value::as_i32() const
{
return static_cast<i32>(as_double());
@ -495,9 +496,17 @@ i32 Value::to_i32(GlobalObject& global_object) const
auto number = to_number(global_object);
if (global_object.vm().exception())
return INVALID;
if (number.is_nan() || number.is_infinity())
double value = number.as_double();
if (!isfinite(value) || value == 0)
return 0;
return number.as_i32();
auto abs = fabs(value);
auto int_val = floor(abs);
if (signbit(value))
int_val = -int_val;
auto int32bit = fmod(int_val, 4294967296.0);
if (int32bit >= 2147483648.0)
int32bit -= 4294967296.0;
return static_cast<i32>(int32bit);
}
u32 Value::to_u32(GlobalObject& global_object) const
@ -506,11 +515,14 @@ u32 Value::to_u32(GlobalObject& global_object) const
auto number = to_number(global_object);
if (global_object.vm().exception())
return INVALID;
if (number.is_nan() || number.is_infinity())
double value = number.as_double();
if (!isfinite(value) || value == 0)
return 0;
if (number.as_double() <= 0)
return 0;
return number.as_u32();
auto int_val = floor(fabs(value));
if (signbit(value))
int_val = -int_val;
auto int32bit = fmod(int_val, NumericLimits<u32>::max() + 1.0);
return static_cast<u32>(int32bit);
}
size_t Value::to_length(GlobalObject& global_object) const
@ -613,7 +625,7 @@ Value bitwise_and(GlobalObject& global_object, Value lhs, Value rhs)
if (both_number(lhs_numeric, rhs_numeric)) {
if (!lhs_numeric.is_finite_number() || !rhs_numeric.is_finite_number())
return Value(0);
return Value((i32)lhs_numeric.as_double() & (i32)rhs_numeric.as_double());
return Value(lhs_numeric.to_i32(global_object.global_object()) & rhs_numeric.to_i32(global_object.global_object()));
}
if (both_bigint(lhs_numeric, rhs_numeric))
return js_bigint(global_object.heap(), lhs_numeric.as_bigint().big_integer().bitwise_and(rhs_numeric.as_bigint().big_integer()));
@ -636,7 +648,7 @@ Value bitwise_or(GlobalObject& global_object, Value lhs, Value rhs)
return rhs_numeric;
if (!rhs_numeric.is_finite_number())
return lhs_numeric;
return Value((i32)lhs_numeric.as_double() | (i32)rhs_numeric.as_double());
return Value(lhs_numeric.to_i32(global_object.global_object()) | rhs_numeric.to_i32(global_object.global_object()));
}
if (both_bigint(lhs_numeric, rhs_numeric))
return js_bigint(global_object.heap(), lhs_numeric.as_bigint().big_integer().bitwise_or(rhs_numeric.as_bigint().big_integer()));
@ -659,7 +671,7 @@ Value bitwise_xor(GlobalObject& global_object, Value lhs, Value rhs)
return rhs_numeric;
if (!rhs_numeric.is_finite_number())
return lhs_numeric;
return Value((i32)lhs_numeric.as_double() ^ (i32)rhs_numeric.as_double());
return Value(lhs_numeric.to_i32(global_object.global_object()) ^ rhs_numeric.to_i32(global_object.global_object()));
}
if (both_bigint(lhs_numeric, rhs_numeric))
return js_bigint(global_object.heap(), lhs_numeric.as_bigint().big_integer().bitwise_xor(rhs_numeric.as_bigint().big_integer()));
@ -704,6 +716,8 @@ Value unary_minus(GlobalObject& global_object, Value lhs)
Value left_shift(GlobalObject& global_object, Value lhs, Value rhs)
{
// 6.1.6.1.9 Number::leftShift
// https://tc39.es/ecma262/#sec-numeric-types-number-leftShift
auto lhs_numeric = lhs.to_numeric(global_object.global_object());
if (global_object.vm().exception())
return {};
@ -715,7 +729,10 @@ Value left_shift(GlobalObject& global_object, Value lhs, Value rhs)
return Value(0);
if (!rhs_numeric.is_finite_number())
return lhs_numeric;
return Value((i32)lhs_numeric.as_double() << (i32)rhs_numeric.as_double());
// Ok, so this performs toNumber() again but that "can't" throw
auto lhs_i32 = lhs_numeric.to_i32(global_object.global_object());
auto rhs_u32 = rhs_numeric.to_u32(global_object.global_object());
return Value(lhs_i32 << rhs_u32);
}
if (both_bigint(lhs_numeric, rhs_numeric))
TODO();
@ -725,6 +742,8 @@ Value left_shift(GlobalObject& global_object, Value lhs, Value rhs)
Value right_shift(GlobalObject& global_object, Value lhs, Value rhs)
{
// 6.1.6.1.11 Number::signedRightShift
// https://tc39.es/ecma262/#sec-numeric-types-number-signedRightShift
auto lhs_numeric = lhs.to_numeric(global_object.global_object());
if (global_object.vm().exception())
return {};
@ -736,7 +755,10 @@ Value right_shift(GlobalObject& global_object, Value lhs, Value rhs)
return Value(0);
if (!rhs_numeric.is_finite_number())
return lhs_numeric;
return Value((i32)lhs_numeric.as_double() >> (i32)rhs_numeric.as_double());
// Ok, so this performs toNumber() again but that "can't" throw
auto lhs_i32 = lhs_numeric.to_i32(global_object.global_object());
auto rhs_u32 = rhs_numeric.to_u32(global_object.global_object());
return Value(lhs_i32 >> rhs_u32);
}
if (both_bigint(lhs_numeric, rhs_numeric))
TODO();
@ -746,6 +768,8 @@ Value right_shift(GlobalObject& global_object, Value lhs, Value rhs)
Value unsigned_right_shift(GlobalObject& global_object, Value lhs, Value rhs)
{
// 6.1.6.1.11 Number::unsignedRightShift
// https://tc39.es/ecma262/#sec-numeric-types-number-unsignedRightShift
auto lhs_numeric = lhs.to_numeric(global_object.global_object());
if (global_object.vm().exception())
return {};
@ -757,7 +781,10 @@ Value unsigned_right_shift(GlobalObject& global_object, Value lhs, Value rhs)
return Value(0);
if (!rhs_numeric.is_finite_number())
return lhs_numeric;
return Value((unsigned)lhs_numeric.as_double() >> (i32)rhs_numeric.as_double());
// Ok, so this performs toNumber() again but that "can't" throw
auto lhs_u32 = lhs_numeric.to_u32(global_object.global_object());
auto rhs_u32 = rhs_numeric.to_u32(global_object.global_object()) % 32;
return Value(lhs_u32 >> rhs_u32);
}
global_object.vm().throw_exception<TypeError>(global_object.global_object(), ErrorType::BigIntBadOperator, "unsigned right-shift");
return {};
@ -1085,9 +1112,9 @@ bool abstract_eq(GlobalObject& global_object, Value lhs, Value rhs)
if ((lhs.is_number() && !lhs.is_integer()) || (rhs.is_number() && !rhs.is_integer()))
return false;
if (lhs.is_number())
return Crypto::SignedBigInteger { lhs.as_i32() } == rhs.as_bigint().big_integer();
return Crypto::SignedBigInteger { lhs.to_i32(global_object.global_object()) } == rhs.as_bigint().big_integer();
else
return Crypto::SignedBigInteger { rhs.as_i32() } == lhs.as_bigint().big_integer();
return Crypto::SignedBigInteger { rhs.to_i32(global_object.global_object()) } == lhs.as_bigint().big_integer();
}
return false;
@ -1194,12 +1221,12 @@ TriState abstract_relation(GlobalObject& global_object, bool left_first, Value l
bool x_lower_than_y;
if (x_numeric.is_number()) {
x_lower_than_y = x_numeric.is_integer()
? Crypto::SignedBigInteger { x_numeric.as_i32() } < y_numeric.as_bigint().big_integer()
: (Crypto::SignedBigInteger { x_numeric.as_i32() } < y_numeric.as_bigint().big_integer() || Crypto::SignedBigInteger { x_numeric.as_i32() + 1 } < y_numeric.as_bigint().big_integer());
? Crypto::SignedBigInteger { x_numeric.to_i32(global_object.global_object()) } < y_numeric.as_bigint().big_integer()
: (Crypto::SignedBigInteger { x_numeric.to_i32(global_object.global_object()) } < y_numeric.as_bigint().big_integer() || Crypto::SignedBigInteger { x_numeric.to_i32(global_object.global_object()) + 1 } < y_numeric.as_bigint().big_integer());
} else {
x_lower_than_y = y_numeric.is_integer()
? x_numeric.as_bigint().big_integer() < Crypto::SignedBigInteger { y_numeric.as_i32() }
: (x_numeric.as_bigint().big_integer() < Crypto::SignedBigInteger { y_numeric.as_i32() } || x_numeric.as_bigint().big_integer() < Crypto::SignedBigInteger { y_numeric.as_i32() + 1 });
? x_numeric.as_bigint().big_integer() < Crypto::SignedBigInteger { y_numeric.to_i32(global_object.global_object()) }
: (x_numeric.as_bigint().big_integer() < Crypto::SignedBigInteger { y_numeric.to_i32(global_object.global_object()) } || x_numeric.as_bigint().big_integer() < Crypto::SignedBigInteger { y_numeric.to_i32(global_object.global_object()) + 1 });
}
if (x_lower_than_y)
return TriState::True;

28
Userland/Libraries/LibJS/Tests/builtins/Math/rounding-modes.js Normal file
View file

@ -0,0 +1,28 @@
test("basic rounding", () => {
expect(Math.round(1.25)).toBe(1);
expect(Math.round(-1.25)).toBe(-1);
expect(Math.round(1.5)).toBe(2);
expect(Math.round(-1.5)).toBe(-1);
expect(Math.round(1.75)).toBe(2);
expect(Math.round(-1.75)).toBe(-2);
expect(Math.round(1)).toBe(1);
expect(Math.round(-1)).toBe(-1);
expect(Math.round(4294967296.5)).toBe(4294967297);
expect(Math.round(-4294967296.5)).toBe(-4294967296);
expect(Math.round(4294967297)).toBe(4294967297);
expect(Math.round(-4294967297)).toBe(-4294967297);
});
test("basic floor", () => {
expect(Math.floor(1.25)).toBe(1);
expect(Math.floor(-1.25)).toBe(-2);
expect(Math.floor(1.5)).toBe(1);
expect(Math.floor(-1.5)).toBe(-2);
expect(Math.floor(1.75)).toBe(1);
expect(Math.floor(-1.75)).toBe(-2);
expect(Math.floor(1)).toBe(1);
expect(Math.floor(-1)).toBe(-1);
expect(Math.floor(4294967296.5)).toBe(4294967296);
expect(Math.floor(-4294967296.5)).toBe(-4294967297);
expect(Math.floor(4294967297)).toBe(4294967297);
expect(Math.floor(-4294967297)).toBe(-4294967297);
});

3
Userland/Libraries/LibJS/Tests/operators/binary-bitwise-and.js
View file

@ -40,6 +40,9 @@ test("basic numeric and", () => {
expect(5 & 3).toBe(1);
expect(5 & 4).toBe(4);
expect(5 & 5).toBe(5);
expect(0xffffffff & 0).toBe(0);
expect(0xffffffff & 0xffffffff).toBe(-1);
});
test("and with non-numeric values", () => {

5
Userland/Libraries/LibJS/Tests/operators/binary-bitwise-left-shift.js
View file

@ -40,6 +40,11 @@ test("basic numeric shifting", () => {
expect(5 << 3).toBe(40);
expect(5 << 4).toBe(80);
expect(5 << 5).toBe(160);
expect(0xffffffff << 0).toBe(-1);
expect(0xffffffff << 16).toBe(-65536);
expect(0xffff0000 << 16).toBe(0);
expect(0xffff0000 << 15).toBe(-2147483648);
});
test("shifting with non-numeric values", () => {

4
Userland/Libraries/LibJS/Tests/operators/binary-bitwise-or.js
View file

@ -40,6 +40,10 @@ test("basic numeric or", () => {
expect(5 | 3).toBe(7);
expect(5 | 4).toBe(5);
expect(5 | 5).toBe(5);
expect(0xffffffff | 0).toBe(-1);
expect(0xffffffff | 0xffffffff).toBe(-1);
expect(2147483648 | 0).toBe(-2147483648);
});
test("or with non-numeric values", () => {

4
Userland/Libraries/LibJS/Tests/operators/binary-bitwise-right-shift.js
View file

@ -26,6 +26,10 @@ test("basic numeric shifting", () => {
expect(42 >> 3).toBe(5);
expect(42 >> 4).toBe(2);
expect(42 >> 5).toBe(1);
expect(0xffffffff >> 0).toBe(-1);
expect(0xffffffff >> 16).toBe(-1);
expect((0xf0000000 * 2) >> 16).toBe(-8192);
});
test("numeric shifting with negative lhs values", () => {

4
Userland/Libraries/LibJS/Tests/operators/binary-bitwise-unsigned-right-shift.js
View file

@ -26,6 +26,10 @@ test("basic numeric shifting", () => {
expect(42 >>> 3).toBe(5);
expect(42 >>> 4).toBe(2);
expect(42 >>> 5).toBe(1);
expect(0xffffffff >>> 0).toBe(4294967295);
expect(0xffffffff >>> 16).toBe(65535);
expect((0xf0000000 * 2) >>> 16).toBe(57344);
});
test("numeric shifting with negative lhs values", () => {

3
Userland/Libraries/LibJS/Tests/operators/binary-bitwise-xor.js
View file

@ -40,6 +40,9 @@ test("basic numeric xor", () => {
expect(5 ^ 3).toBe(6);
expect(5 ^ 4).toBe(1);
expect(5 ^ 5).toBe(0);
expect(0xffffffff ^ 0).toBe(-1);
expect(0xffffffff ^ 0xffffffff).toBe(0);
});
test("xor with non-numeric values", () => {