Javascript
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666行
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18.64 KB
// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This files contains runtime support implemented in JavaScript.
// CAUTION: Some of the functions specified in this file are called
// directly from compiled code. These are the functions with names in
// ALL CAPS. The compiled code passes the first argument in 'this' and
// it does not push the function onto the stack. This means that you
// cannot use contexts in all these functions.
/* -----------------------------------
- - - C o m p a r i s o n - - -
-----------------------------------
*/
// The following declarations are shared with other native JS files.
// They are all declared at this one spot to avoid redeclaration errors.
var $Object = global.Object;
var $Array = global.Array;
var $String = global.String;
var $Number = global.Number;
var $Function = global.Function;
var $Boolean = global.Boolean;
var $NaN = %GetRootNaN();
// ECMA-262 Section 11.9.3.
function EQUALS(y) {
if (IS_STRING(this) && IS_STRING(y)) return %StringEquals(this, y);
var x = this;
while (true) {
if (IS_NUMBER(x)) {
while (true) {
if (IS_NUMBER(y)) return %NumberEquals(x, y);
if (IS_NULL_OR_UNDEFINED(y)) return 1; // not equal
if (IS_SYMBOL(y)) return 1; // not equal
if (!IS_SPEC_OBJECT(y)) {
// String or boolean.
return %NumberEquals(x, %ToNumber(y));
}
y = %ToPrimitive(y, NO_HINT);
}
} else if (IS_STRING(x)) {
while (true) {
if (IS_STRING(y)) return %StringEquals(x, y);
if (IS_SYMBOL(y)) return 1; // not equal
if (IS_NUMBER(y)) return %NumberEquals(%ToNumber(x), y);
if (IS_BOOLEAN(y)) return %NumberEquals(%ToNumber(x), %ToNumber(y));
if (IS_NULL_OR_UNDEFINED(y)) return 1; // not equal
y = %ToPrimitive(y, NO_HINT);
}
} else if (IS_SYMBOL(x)) {
if (IS_SYMBOL(y)) return %_ObjectEquals(x, y) ? 0 : 1;
return 1; // not equal
} else if (IS_BOOLEAN(x)) {
if (IS_BOOLEAN(y)) return %_ObjectEquals(x, y) ? 0 : 1;
if (IS_NULL_OR_UNDEFINED(y)) return 1;
if (IS_NUMBER(y)) return %NumberEquals(%ToNumber(x), y);
if (IS_STRING(y)) return %NumberEquals(%ToNumber(x), %ToNumber(y));
if (IS_SYMBOL(y)) return 1; // not equal
// y is object.
x = %ToNumber(x);
y = %ToPrimitive(y, NO_HINT);
} else if (IS_NULL_OR_UNDEFINED(x)) {
return IS_NULL_OR_UNDEFINED(y) ? 0 : 1;
} else {
// x is an object.
if (IS_SPEC_OBJECT(y)) {
return %_ObjectEquals(x, y) ? 0 : 1;
}
if (IS_NULL_OR_UNDEFINED(y)) return 1; // not equal
if (IS_SYMBOL(y)) return 1; // not equal
if (IS_BOOLEAN(y)) y = %ToNumber(y);
x = %ToPrimitive(x, NO_HINT);
}
}
}
// ECMA-262, section 11.9.4, page 56.
function STRICT_EQUALS(x) {
if (IS_STRING(this)) {
if (!IS_STRING(x)) return 1; // not equal
return %StringEquals(this, x);
}
if (IS_NUMBER(this)) {
if (!IS_NUMBER(x)) return 1; // not equal
return %NumberEquals(this, x);
}
// If anything else gets here, we just do simple identity check.
// Objects (including functions), null, undefined and booleans were
// checked in the CompareStub, so there should be nothing left.
return %_ObjectEquals(this, x) ? 0 : 1;
}
// ECMA-262, section 11.8.5, page 53. The 'ncr' parameter is used as
// the result when either (or both) the operands are NaN.
function COMPARE(x, ncr) {
var left;
var right;
// Fast cases for string, numbers and undefined compares.
if (IS_STRING(this)) {
if (IS_STRING(x)) return %_StringCompare(this, x);
if (IS_UNDEFINED(x)) return ncr;
left = this;
} else if (IS_NUMBER(this)) {
if (IS_NUMBER(x)) return %NumberCompare(this, x, ncr);
if (IS_UNDEFINED(x)) return ncr;
left = this;
} else if (IS_UNDEFINED(this)) {
if (!IS_UNDEFINED(x)) {
%ToPrimitive(x, NUMBER_HINT);
}
return ncr;
} else if (IS_UNDEFINED(x)) {
%ToPrimitive(this, NUMBER_HINT);
return ncr;
} else {
left = %ToPrimitive(this, NUMBER_HINT);
}
right = %ToPrimitive(x, NUMBER_HINT);
if (IS_STRING(left) && IS_STRING(right)) {
return %_StringCompare(left, right);
} else {
var left_number = %ToNumber(left);
var right_number = %ToNumber(right);
if (NUMBER_IS_NAN(left_number) || NUMBER_IS_NAN(right_number)) return ncr;
return %NumberCompare(left_number, right_number, ncr);
}
}
/* -----------------------------------
- - - A r i t h m e t i c - - -
-----------------------------------
*/
// ECMA-262, section 11.6.1, page 50.
function ADD(x) {
// Fast case: Check for number operands and do the addition.
if (IS_NUMBER(this) && IS_NUMBER(x)) return %NumberAdd(this, x);
if (IS_STRING(this) && IS_STRING(x)) return %_StringAdd(this, x);
// Default implementation.
var a = %ToPrimitive(this, NO_HINT);
var b = %ToPrimitive(x, NO_HINT);
if (IS_STRING(a)) {
return %_StringAdd(a, %ToString(b));
} else if (IS_STRING(b)) {
return %_StringAdd(%NonStringToString(a), b);
} else {
return %NumberAdd(%ToNumber(a), %ToNumber(b));
}
}
// Left operand (this) is already a string.
function STRING_ADD_LEFT(y) {
if (!IS_STRING(y)) {
if (IS_STRING_WRAPPER(y) && %_IsStringWrapperSafeForDefaultValueOf(y)) {
y = %_ValueOf(y);
} else {
y = IS_NUMBER(y)
? %_NumberToString(y)
: %ToString(%ToPrimitive(y, NO_HINT));
}
}
return %_StringAdd(this, y);
}
// Right operand (y) is already a string.
function STRING_ADD_RIGHT(y) {
var x = this;
if (!IS_STRING(x)) {
if (IS_STRING_WRAPPER(x) && %_IsStringWrapperSafeForDefaultValueOf(x)) {
x = %_ValueOf(x);
} else {
x = IS_NUMBER(x)
? %_NumberToString(x)
: %ToString(%ToPrimitive(x, NO_HINT));
}
}
return %_StringAdd(x, y);
}
// ECMA-262, section 11.6.2, page 50.
function SUB(y) {
var x = IS_NUMBER(this) ? this : %NonNumberToNumber(this);
if (!IS_NUMBER(y)) y = %NonNumberToNumber(y);
return %NumberSub(x, y);
}
// ECMA-262, section 11.5.1, page 48.
function MUL(y) {
var x = IS_NUMBER(this) ? this : %NonNumberToNumber(this);
if (!IS_NUMBER(y)) y = %NonNumberToNumber(y);
return %NumberMul(x, y);
}
// ECMA-262, section 11.5.2, page 49.
function DIV(y) {
var x = IS_NUMBER(this) ? this : %NonNumberToNumber(this);
if (!IS_NUMBER(y)) y = %NonNumberToNumber(y);
return %NumberDiv(x, y);
}
// ECMA-262, section 11.5.3, page 49.
function MOD(y) {
var x = IS_NUMBER(this) ? this : %NonNumberToNumber(this);
if (!IS_NUMBER(y)) y = %NonNumberToNumber(y);
return %NumberMod(x, y);
}
/* -------------------------------------------
- - - B i t o p e r a t i o n s - - -
-------------------------------------------
*/
// ECMA-262, section 11.10, page 57.
function BIT_OR(y) {
var x = IS_NUMBER(this) ? this : %NonNumberToNumber(this);
if (!IS_NUMBER(y)) y = %NonNumberToNumber(y);
return %NumberOr(x, y);
}
// ECMA-262, section 11.10, page 57.
function BIT_AND(y) {
var x;
if (IS_NUMBER(this)) {
x = this;
if (!IS_NUMBER(y)) y = %NonNumberToNumber(y);
} else {
x = %NonNumberToNumber(this);
// Make sure to convert the right operand to a number before
// bailing out in the fast case, but after converting the
// left operand. This ensures that valueOf methods on the right
// operand are always executed.
if (!IS_NUMBER(y)) y = %NonNumberToNumber(y);
// Optimize for the case where we end up AND'ing a value
// that doesn't convert to a number. This is common in
// certain benchmarks.
if (NUMBER_IS_NAN(x)) return 0;
}
return %NumberAnd(x, y);
}
// ECMA-262, section 11.10, page 57.
function BIT_XOR(y) {
var x = IS_NUMBER(this) ? this : %NonNumberToNumber(this);
if (!IS_NUMBER(y)) y = %NonNumberToNumber(y);
return %NumberXor(x, y);
}
// ECMA-262, section 11.7.1, page 51.
function SHL(y) {
var x = IS_NUMBER(this) ? this : %NonNumberToNumber(this);
if (!IS_NUMBER(y)) y = %NonNumberToNumber(y);
return %NumberShl(x, y);
}
// ECMA-262, section 11.7.2, page 51.
function SAR(y) {
var x;
if (IS_NUMBER(this)) {
x = this;
if (!IS_NUMBER(y)) y = %NonNumberToNumber(y);
} else {
x = %NonNumberToNumber(this);
// Make sure to convert the right operand to a number before
// bailing out in the fast case, but after converting the
// left operand. This ensures that valueOf methods on the right
// operand are always executed.
if (!IS_NUMBER(y)) y = %NonNumberToNumber(y);
// Optimize for the case where we end up shifting a value
// that doesn't convert to a number. This is common in
// certain benchmarks.
if (NUMBER_IS_NAN(x)) return 0;
}
return %NumberSar(x, y);
}
// ECMA-262, section 11.7.3, page 52.
function SHR(y) {
var x = IS_NUMBER(this) ? this : %NonNumberToNumber(this);
if (!IS_NUMBER(y)) y = %NonNumberToNumber(y);
return %NumberShr(x, y);
}
/* -----------------------------
- - - H e l p e r s - - -
-----------------------------
*/
// ECMA-262, section 11.4.1, page 46.
function DELETE(key, strict) {
return %DeleteProperty(%ToObject(this), %ToName(key), strict);
}
// ECMA-262, section 11.8.7, page 54.
function IN(x) {
if (!IS_SPEC_OBJECT(x)) {
throw %MakeTypeError('invalid_in_operator_use', [this, x]);
}
return %_IsNonNegativeSmi(this) ?
%HasElement(x, this) : %HasProperty(x, %ToName(this));
}
// ECMA-262, section 11.8.6, page 54. To make the implementation more
// efficient, the return value should be zero if the 'this' is an
// instance of F, and non-zero if not. This makes it possible to avoid
// an expensive ToBoolean conversion in the generated code.
function INSTANCE_OF(F) {
var V = this;
if (!IS_SPEC_FUNCTION(F)) {
throw %MakeTypeError('instanceof_function_expected', [F]);
}
// If V is not an object, return false.
if (!IS_SPEC_OBJECT(V)) {
return 1;
}
// Check if function is bound, if so, get [[BoundFunction]] from it
// and use that instead of F.
var bindings = %BoundFunctionGetBindings(F);
if (bindings) {
F = bindings[kBoundFunctionIndex]; // Always a non-bound function.
}
// Get the prototype of F; if it is not an object, throw an error.
var O = F.prototype;
if (!IS_SPEC_OBJECT(O)) {
throw %MakeTypeError('instanceof_nonobject_proto', [O]);
}
// Return whether or not O is in the prototype chain of V.
return %IsInPrototypeChain(O, V) ? 0 : 1;
}
// Filter a given key against an object by checking if the object
// has a property with the given key; return the key as a string if
// it has. Otherwise returns 0 (smi). Used in for-in statements.
function FILTER_KEY(key) {
var string = %ToName(key);
if (%HasProperty(this, string)) return string;
return 0;
}
function CALL_NON_FUNCTION() {
var delegate = %GetFunctionDelegate(this);
if (!IS_FUNCTION(delegate)) {
throw %MakeTypeError('called_non_callable', [typeof this]);
}
return %Apply(delegate, this, arguments, 0, %_ArgumentsLength());
}
function CALL_NON_FUNCTION_AS_CONSTRUCTOR() {
var delegate = %GetConstructorDelegate(this);
if (!IS_FUNCTION(delegate)) {
throw %MakeTypeError('called_non_callable', [typeof this]);
}
return %Apply(delegate, this, arguments, 0, %_ArgumentsLength());
}
function CALL_FUNCTION_PROXY() {
var arity = %_ArgumentsLength() - 1;
var proxy = %_Arguments(arity); // The proxy comes in as an additional arg.
var trap = %GetCallTrap(proxy);
return %Apply(trap, this, arguments, 0, arity);
}
function CALL_FUNCTION_PROXY_AS_CONSTRUCTOR() {
var proxy = this;
var trap = %GetConstructTrap(proxy);
return %Apply(trap, this, arguments, 0, %_ArgumentsLength());
}
function APPLY_PREPARE(args) {
var length;
// First check whether length is a positive Smi and args is an
// array. This is the fast case. If this fails, we do the slow case
// that takes care of more eventualities.
if (IS_ARRAY(args)) {
length = args.length;
if (%_IsSmi(length) && length >= 0 && length < 0x800000 &&
IS_SPEC_FUNCTION(this)) {
return length;
}
}
length = (args == null) ? 0 : %ToUint32(args.length);
// We can handle any number of apply arguments if the stack is
// big enough, but sanity check the value to avoid overflow when
// multiplying with pointer size.
if (length > 0x800000) {
throw %MakeRangeError('stack_overflow', []);
}
if (!IS_SPEC_FUNCTION(this)) {
throw %MakeTypeError('apply_non_function',
[ %ToString(this), typeof this ]);
}
// Make sure the arguments list has the right type.
if (args != null && !IS_SPEC_OBJECT(args)) {
throw %MakeTypeError('apply_wrong_args', []);
}
// Return the length which is the number of arguments to copy to the
// stack. It is guaranteed to be a small integer at this point.
return length;
}
function STACK_OVERFLOW(length) {
throw %MakeRangeError('stack_overflow', []);
}
// Convert the receiver to an object - forward to ToObject.
function TO_OBJECT() {
return %ToObject(this);
}
// Convert the receiver to a number - forward to ToNumber.
function TO_NUMBER() {
return %ToNumber(this);
}
// Convert the receiver to a string - forward to ToString.
function TO_STRING() {
return %ToString(this);
}
/* -------------------------------------
- - - C o n v e r s i o n s - - -
-------------------------------------
*/
// ECMA-262, section 9.1, page 30. Use null/undefined for no hint,
// (1) for number hint, and (2) for string hint.
function ToPrimitive(x, hint) {
// Fast case check.
if (IS_STRING(x)) return x;
// Normal behavior.
if (!IS_SPEC_OBJECT(x)) return x;
if (IS_SYMBOL_WRAPPER(x)) throw MakeTypeError('symbol_to_primitive', []);
if (hint == NO_HINT) hint = (IS_DATE(x)) ? STRING_HINT : NUMBER_HINT;
return (hint == NUMBER_HINT) ? %DefaultNumber(x) : %DefaultString(x);
}
// ECMA-262, section 9.2, page 30
function ToBoolean(x) {
if (IS_BOOLEAN(x)) return x;
if (IS_STRING(x)) return x.length != 0;
if (x == null) return false;
if (IS_NUMBER(x)) return !((x == 0) || NUMBER_IS_NAN(x));
return true;
}
// ECMA-262, section 9.3, page 31.
function ToNumber(x) {
if (IS_NUMBER(x)) return x;
if (IS_STRING(x)) {
return %_HasCachedArrayIndex(x) ? %_GetCachedArrayIndex(x)
: %StringToNumber(x);
}
if (IS_BOOLEAN(x)) return x ? 1 : 0;
if (IS_UNDEFINED(x)) return NAN;
if (IS_SYMBOL(x)) throw MakeTypeError('symbol_to_number', []);
return (IS_NULL(x)) ? 0 : ToNumber(%DefaultNumber(x));
}
function NonNumberToNumber(x) {
if (IS_STRING(x)) {
return %_HasCachedArrayIndex(x) ? %_GetCachedArrayIndex(x)
: %StringToNumber(x);
}
if (IS_BOOLEAN(x)) return x ? 1 : 0;
if (IS_UNDEFINED(x)) return NAN;
if (IS_SYMBOL(x)) throw MakeTypeError('symbol_to_number', []);
return (IS_NULL(x)) ? 0 : ToNumber(%DefaultNumber(x));
}
// ECMA-262, section 9.8, page 35.
function ToString(x) {
if (IS_STRING(x)) return x;
if (IS_NUMBER(x)) return %_NumberToString(x);
if (IS_BOOLEAN(x)) return x ? 'true' : 'false';
if (IS_UNDEFINED(x)) return 'undefined';
if (IS_SYMBOL(x)) throw %MakeTypeError('symbol_to_string', []);
return (IS_NULL(x)) ? 'null' : %ToString(%DefaultString(x));
}
function NonStringToString(x) {
if (IS_NUMBER(x)) return %_NumberToString(x);
if (IS_BOOLEAN(x)) return x ? 'true' : 'false';
if (IS_UNDEFINED(x)) return 'undefined';
if (IS_SYMBOL(x)) throw %MakeTypeError('symbol_to_string', []);
return (IS_NULL(x)) ? 'null' : %ToString(%DefaultString(x));
}
// ES6 symbols
function ToName(x) {
return IS_SYMBOL(x) ? x : %ToString(x);
}
// ECMA-262, section 9.9, page 36.
function ToObject(x) {
if (IS_STRING(x)) return new $String(x);
if (IS_NUMBER(x)) return new $Number(x);
if (IS_BOOLEAN(x)) return new $Boolean(x);
if (IS_SYMBOL(x)) return %NewSymbolWrapper(x);
if (IS_NULL_OR_UNDEFINED(x) && !IS_UNDETECTABLE(x)) {
throw %MakeTypeError('undefined_or_null_to_object', []);
}
return x;
}
// ECMA-262, section 9.4, page 34.
function ToInteger(x) {
if (%_IsSmi(x)) return x;
return %NumberToInteger(ToNumber(x));
}
// ES6, draft 08-24-14, section 7.1.15
function ToLength(arg) {
arg = ToInteger(arg);
if (arg < 0) return 0;
return arg < $Number.MAX_SAFE_INTEGER ? arg : $Number.MAX_SAFE_INTEGER;
}
// ECMA-262, section 9.6, page 34.
function ToUint32(x) {
if (%_IsSmi(x) && x >= 0) return x;
return %NumberToJSUint32(ToNumber(x));
}
// ECMA-262, section 9.5, page 34
function ToInt32(x) {
if (%_IsSmi(x)) return x;
return %NumberToJSInt32(ToNumber(x));
}
// ES5, section 9.12
function SameValue(x, y) {
if (typeof x != typeof y) return false;
if (IS_NUMBER(x)) {
if (NUMBER_IS_NAN(x) && NUMBER_IS_NAN(y)) return true;
// x is +0 and y is -0 or vice versa.
if (x === 0 && y === 0 && %_IsMinusZero(x) != %_IsMinusZero(y)) {
return false;
}
}
return x === y;
}
/* ---------------------------------
- - - U t i l i t i e s - - -
---------------------------------
*/
// Returns if the given x is a primitive value - not an object or a
// function.
function IsPrimitive(x) {
// Even though the type of null is "object", null is still
// considered a primitive value. IS_SPEC_OBJECT handles this correctly
// (i.e., it will return false if x is null).
return !IS_SPEC_OBJECT(x);
}
// ECMA-262, section 8.6.2.6, page 28.
function DefaultNumber(x) {
if (!IS_SYMBOL_WRAPPER(x)) {
var valueOf = x.valueOf;
if (IS_SPEC_FUNCTION(valueOf)) {
var v = %_CallFunction(x, valueOf);
if (%IsPrimitive(v)) return v;
}
var toString = x.toString;
if (IS_SPEC_FUNCTION(toString)) {
var s = %_CallFunction(x, toString);
if (%IsPrimitive(s)) return s;
}
}
throw %MakeTypeError('cannot_convert_to_primitive', []);
}
// ECMA-262, section 8.6.2.6, page 28.
function DefaultString(x) {
if (!IS_SYMBOL_WRAPPER(x)) {
var toString = x.toString;
if (IS_SPEC_FUNCTION(toString)) {
var s = %_CallFunction(x, toString);
if (%IsPrimitive(s)) return s;
}
var valueOf = x.valueOf;
if (IS_SPEC_FUNCTION(valueOf)) {
var v = %_CallFunction(x, valueOf);
if (%IsPrimitive(v)) return v;
}
}
throw %MakeTypeError('cannot_convert_to_primitive', []);
}
function ToPositiveInteger(x, rangeErrorName) {
var i = TO_INTEGER(x);
if (i < 0) throw MakeRangeError(rangeErrorName);
return i;
}
// NOTE: Setting the prototype for Array must take place as early as
// possible due to code generation for array literals. When
// generating code for a array literal a boilerplate array is created
// that is cloned when running the code. It is essential that the
// boilerplate gets the right prototype.
%FunctionSetPrototype($Array, new $Array(0));