CSE2410 Fall 2014 Bounce

// Copyright 2006-2008 the V8 project authors. All rights reserved.

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

//

//     * Redistributions of source code must retain the above copyright

//       notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above

//       copyright notice, this list of conditions and the following

//       disclaimer in the documentation and/or other materials provided

//       with the distribution.

//     * Neither the name of Google Inc. nor the names of its

//       contributors may be used to endorse or promote products derived

//       from this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// 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();

var builtins = this;

// 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_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)) {

      while (true) {

        if (IS_SYMBOL(y)) return %_ObjectEquals(x, y) ? 0 : 1;

        if (!IS_SPEC_OBJECT(y)) return 1;  // not equal

        y = %ToPrimitive(y, NO_HINT);

      }

    } 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_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', [V]);

  }

  // 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 APPLY_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)) return %_ValueOf(x);

  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)) return NAN;

  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)) return NAN;

  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';

  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';

  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_SYMBOL(x)) return new $Symbol(x);

  if (IS_NUMBER(x)) return new $Number(x);

  if (IS_BOOLEAN(x)) return new $Boolean(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));

}

// 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 && (1 / x) != (1 / 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) {

  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) {

  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));