Merge WebKit at r75315: Initial merge by git.

Change-Id: I570314b346ce101c935ed22a626b48c2af266b84

1 files changed, 568 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/runtime/JSImmediate.h b/Source/JavaScriptCore/runtime/JSImmediate.h
new file mode 100644
index 0000000..68ba75c
--- /dev/null
+++ b/Source/JavaScriptCore/runtime/JSImmediate.h
@@ -0,0 +1,568 @@
+/*
+ *  Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
+ *  Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Library General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Library General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Library General Public License
+ *  along with this library; see the file COPYING.LIB.  If not, write to
+ *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ *  Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef JSImmediate_h
+#define JSImmediate_h
+
+#if USE(JSVALUE64)
+
+#include <wtf/Assertions.h>
+#include <wtf/AlwaysInline.h>
+#include <wtf/MathExtras.h>
+#include <wtf/StdLibExtras.h>
+#include "JSValue.h"
+#include <limits>
+#include <limits.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+namespace JSC {
+
+    class ExecState;
+    class JSCell;
+    class JSGlobalData;
+    class JSObject;
+    class UString;
+
+    inline intptr_t reinterpretDoubleToIntptr(double value)
+    {
+        return WTF::bitwise_cast<intptr_t>(value);
+    }
+
+    inline double reinterpretIntptrToDouble(intptr_t value)
+    {
+        return WTF::bitwise_cast<double>(value);
+    }
+
+    /*
+     * A JSValue* is either a pointer to a cell (a heap-allocated object) or an immediate (a type-tagged 
+     * value masquerading as a pointer). The low two bits in a JSValue* are available for type tagging
+     * because allocator alignment guarantees they will be 00 in cell pointers.
+     *
+     * For example, on a 32 bit system:
+     *
+     * JSCell*:             XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX                     00
+     *                      [ high 30 bits: pointer address ]  [ low 2 bits -- always 0 ]
+     * JSImmediate:         XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX                     TT
+     *                      [ high 30 bits: 'payload' ]             [ low 2 bits -- tag ]
+     *
+     * Where the bottom two bits are non-zero they either indicate that the immediate is a 31 bit signed
+     * integer, or they mark the value as being an immediate of a type other than integer, with a secondary
+     * tag used to indicate the exact type.
+     *
+     * Where the lowest bit is set (TT is equal to 01 or 11) the high 31 bits form a 31 bit signed int value.
+     * Where TT is equal to 10 this indicates this is a type of immediate other than an integer, and the next
+     * two bits will form an extended tag.
+     *
+     * 31 bit signed int:   XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX                     X1
+     *                      [ high 30 bits of the value ]      [ high bit part of value ]
+     * Other:               YYYYYYYYYYYYYYYYYYYYYYYYYYYY      ZZ               10
+     *                      [ extended 'payload' ]  [  extended tag  ]  [  tag 'other'  ]
+     *
+     * Where the first bit of the extended tag is set this flags the value as being a boolean, and the following
+     * bit would flag the value as undefined.  If neither bits are set, the value is null.
+     *
+     * Other:               YYYYYYYYYYYYYYYYYYYYYYYYYYYY      UB               10
+     *                      [ extended 'payload' ]  [ undefined | bool ]  [ tag 'other' ]
+     *
+     * For boolean value the lowest bit in the payload holds the value of the bool, all remaining bits are zero.
+     * For undefined or null immediates the payload is zero.
+     *
+     * Boolean:             000000000000000000000000000V      01               10
+     *                      [ boolean value ]              [ bool ]       [ tag 'other' ]
+     * Undefined:           0000000000000000000000000000      10               10
+     *                      [ zero ]                    [ undefined ]     [ tag 'other' ]
+     * Null:                0000000000000000000000000000      00               10
+     *                      [ zero ]                       [ zero ]       [ tag 'other' ]
+     */
+
+    /*
+     * On 64-bit platforms, we support an alternative encoding form for immediates, if
+     * USE(JSVALUE64) is defined.  When this format is used, double precision
+     * floating point values may also be encoded as JSImmediates.
+     *
+     * The encoding makes use of unused NaN space in the IEEE754 representation.  Any value
+     * with the top 13 bits set represents a QNaN (with the sign bit set).  QNaN values
+     * can encode a 51-bit payload.  Hardware produced and C-library payloads typically
+     * have a payload of zero.  We assume that non-zero payloads are available to encode
+     * pointer and integer values.  Since any 64-bit bit pattern where the top 15 bits are
+     * all set represents a NaN with a non-zero payload, we can use this space in the NaN
+     * ranges to encode other values (however there are also other ranges of NaN space that
+     * could have been selected).  This range of NaN space is represented by 64-bit numbers
+     * begining with the 16-bit hex patterns 0xFFFE and 0xFFFF - we rely on the fact that no
+     * valid double-precision numbers will begin fall in these ranges.
+     *
+     * The scheme we have implemented encodes double precision values by adding 2^48 to the
+     * 64-bit integer representation of the number.  After this manipulation, no encoded
+     * double-precision value will begin with the pattern 0x0000 or 0xFFFF.
+     *
+     * The top 16-bits denote the type of the encoded JSImmediate:
+     *
+     * Pointer: 0000:PPPP:PPPP:PPPP
+     *          0001:****:****:****
+     * Double:{         ...
+     *          FFFE:****:****:****
+     * Integer: FFFF:0000:IIII:IIII
+     *
+     * 32-bit signed integers are marked with the 16-bit tag 0xFFFF.  The tag 0x0000
+     * denotes a pointer, or another form of tagged immediate.  Boolean, null and undefined
+     * values are encoded in the same manner as the default format.
+     */
+
+    class JSImmediate {
+    private:
+        friend class JIT;
+        friend class JSValue;
+        friend class JSInterfaceJIT;
+        friend class SpecializedThunkJIT;
+        friend JSValue jsNumber(ExecState* exec, double d);
+        friend JSValue jsNumber(ExecState*, char i);
+        friend JSValue jsNumber(ExecState*, unsigned char i);
+        friend JSValue jsNumber(ExecState*, short i);
+        friend JSValue jsNumber(ExecState*, unsigned short i);
+        friend JSValue jsNumber(ExecState* exec, int i);
+        friend JSValue jsNumber(ExecState* exec, unsigned i);
+        friend JSValue jsNumber(ExecState* exec, long i);
+        friend JSValue jsNumber(ExecState* exec, unsigned long i);
+        friend JSValue jsNumber(ExecState* exec, long long i);
+        friend JSValue jsNumber(ExecState* exec, unsigned long long i);
+        friend JSValue jsNumber(JSGlobalData* globalData, double d);
+        friend JSValue jsNumber(JSGlobalData* globalData, short i);
+        friend JSValue jsNumber(JSGlobalData* globalData, unsigned short i);
+        friend JSValue jsNumber(JSGlobalData* globalData, int i);
+        friend JSValue jsNumber(JSGlobalData* globalData, unsigned i);
+        friend JSValue jsNumber(JSGlobalData* globalData, long i);
+        friend JSValue jsNumber(JSGlobalData* globalData, unsigned long i);
+        friend JSValue jsNumber(JSGlobalData* globalData, long long i);
+        friend JSValue jsNumber(JSGlobalData* globalData, unsigned long long i);
+
+        // If all bits in the mask are set, this indicates an integer number,
+        // if any but not all are set this value is a double precision number.
+        static const intptr_t TagTypeNumber = 0xffff000000000000ll;
+        // This value is 2^48, used to encode doubles such that the encoded value will begin
+        // with a 16-bit pattern within the range 0x0001..0xFFFE.
+        static const intptr_t DoubleEncodeOffset = 0x1000000000000ll;
+        static const intptr_t TagBitTypeOther   = 0x2; // second bit set indicates immediate other than an integer
+        static const intptr_t TagMask           = TagTypeNumber | TagBitTypeOther;
+
+        static const intptr_t ExtendedTagMask         = 0xC; // extended tag holds a further two bits
+        static const intptr_t ExtendedTagBitBool      = 0x4;
+        static const intptr_t ExtendedTagBitUndefined = 0x8;
+
+        static const intptr_t FullTagTypeMask      = TagMask | ExtendedTagMask;
+        static const intptr_t FullTagTypeBool      = TagBitTypeOther | ExtendedTagBitBool;
+        static const intptr_t FullTagTypeUndefined = TagBitTypeOther | ExtendedTagBitUndefined;
+        static const intptr_t FullTagTypeNull      = TagBitTypeOther;
+
+        static const int32_t IntegerPayloadShift  = 0;
+        static const int32_t ExtendedPayloadShift = 4;
+
+        static const intptr_t ExtendedPayloadBitBoolValue = 1 << ExtendedPayloadShift;
+
+        static const int32_t signBit = 0x80000000;
+ 
+        static ALWAYS_INLINE bool isImmediate(JSValue v)
+        {
+            return rawValue(v) & TagMask;
+        }
+        
+        static ALWAYS_INLINE bool isNumber(JSValue v)
+        {
+            return rawValue(v) & TagTypeNumber;
+        }
+
+        static ALWAYS_INLINE bool isIntegerNumber(JSValue v)
+        {
+            return (rawValue(v) & TagTypeNumber) == TagTypeNumber;
+        }
+
+        static ALWAYS_INLINE bool isDouble(JSValue v)
+        {
+            return isNumber(v) && !isIntegerNumber(v);
+        }
+
+        static ALWAYS_INLINE bool isPositiveIntegerNumber(JSValue v)
+        {
+            // A single mask to check for the sign bit and the number tag all at once.
+            return (rawValue(v) & (signBit | TagTypeNumber)) == TagTypeNumber;
+        }
+        
+        static ALWAYS_INLINE bool isBoolean(JSValue v)
+        {
+            return (rawValue(v) & FullTagTypeMask) == FullTagTypeBool;
+        }
+        
+        static ALWAYS_INLINE bool isUndefinedOrNull(JSValue v)
+        {
+            // Undefined and null share the same value, bar the 'undefined' bit in the extended tag.
+            return (rawValue(v) & ~ExtendedTagBitUndefined) == FullTagTypeNull;
+        }
+
+        static JSValue from(char);
+        static JSValue from(signed char);
+        static JSValue from(unsigned char);
+        static JSValue from(short);
+        static JSValue from(unsigned short);
+        static JSValue from(int);
+        static JSValue from(unsigned);
+        static JSValue from(long);
+        static JSValue from(unsigned long);
+        static JSValue from(long long);
+        static JSValue from(unsigned long long);
+        static JSValue from(double);
+
+        static ALWAYS_INLINE bool isEitherImmediate(JSValue v1, JSValue v2)
+        {
+            return (rawValue(v1) | rawValue(v2)) & TagMask;
+        }
+
+        static ALWAYS_INLINE bool areBothImmediate(JSValue v1, JSValue v2)
+        {
+            return isImmediate(v1) & isImmediate(v2);
+        }
+
+        static ALWAYS_INLINE bool areBothImmediateIntegerNumbers(JSValue v1, JSValue v2)
+        {
+            return (rawValue(v1) & rawValue(v2) & TagTypeNumber) == TagTypeNumber;
+        }
+
+        static double toDouble(JSValue);
+        static bool toBoolean(JSValue);
+
+        static bool getUInt32(JSValue, uint32_t&);
+        static bool getTruncatedInt32(JSValue, int32_t&);
+        static bool getTruncatedUInt32(JSValue, uint32_t&);
+
+        static int32_t getTruncatedInt32(JSValue);
+        static uint32_t getTruncatedUInt32(JSValue);
+
+        static JSValue trueImmediate();
+        static JSValue falseImmediate();
+        static JSValue undefinedImmediate();
+        static JSValue nullImmediate();
+        static JSValue zeroImmediate();
+        static JSValue oneImmediate();
+
+    private:
+        static const int minImmediateInt = ((-INT_MAX) - 1);
+        static const int maxImmediateInt = INT_MAX;
+        static const unsigned maxImmediateUInt = maxImmediateInt;
+
+        static ALWAYS_INLINE JSValue makeValue(intptr_t integer)
+        {
+            return JSValue::makeImmediate(integer);
+        }
+
+        // With USE(JSVALUE64) we want the argument to be zero extended, so the
+        // integer doesn't interfere with the tag bits in the upper word.  In the default encoding,
+        // if intptr_t id larger then int32_t we sign extend the value through the upper word.
+        static ALWAYS_INLINE JSValue makeInt(uint32_t value)
+        {
+            return makeValue((static_cast<intptr_t>(value) << IntegerPayloadShift) | TagTypeNumber);
+        }
+        
+        static ALWAYS_INLINE JSValue makeDouble(double value)
+        {
+            return makeValue(reinterpretDoubleToIntptr(value) + DoubleEncodeOffset);
+        }
+        
+        static ALWAYS_INLINE JSValue makeBool(bool b)
+        {
+            return makeValue((static_cast<intptr_t>(b) << ExtendedPayloadShift) | FullTagTypeBool);
+        }
+        
+        static ALWAYS_INLINE JSValue makeUndefined()
+        {
+            return makeValue(FullTagTypeUndefined);
+        }
+        
+        static ALWAYS_INLINE JSValue makeNull()
+        {
+            return makeValue(FullTagTypeNull);
+        }
+
+        template<typename T>
+        static JSValue fromNumberOutsideIntegerRange(T);
+
+        static ALWAYS_INLINE double doubleValue(JSValue v)
+        {
+            return reinterpretIntptrToDouble(rawValue(v) - DoubleEncodeOffset);
+        }
+
+        static ALWAYS_INLINE int32_t intValue(JSValue v)
+        {
+            return static_cast<int32_t>(rawValue(v) >> IntegerPayloadShift);
+        }
+        
+        static ALWAYS_INLINE uint32_t uintValue(JSValue v)
+        {
+            return static_cast<uint32_t>(rawValue(v) >> IntegerPayloadShift);
+        }
+        
+        static ALWAYS_INLINE bool boolValue(JSValue v)
+        {
+            return rawValue(v) & ExtendedPayloadBitBoolValue;
+        }
+        
+        static ALWAYS_INLINE intptr_t rawValue(JSValue v)
+        {
+            return v.immediateValue();
+        }
+    };
+
+    ALWAYS_INLINE JSValue JSImmediate::trueImmediate() { return makeBool(true); }
+    ALWAYS_INLINE JSValue JSImmediate::falseImmediate() { return makeBool(false); }
+    ALWAYS_INLINE JSValue JSImmediate::undefinedImmediate() { return makeUndefined(); }
+    ALWAYS_INLINE JSValue JSImmediate::nullImmediate() { return makeNull(); }
+    ALWAYS_INLINE JSValue JSImmediate::zeroImmediate() { return makeInt(0); }
+    ALWAYS_INLINE JSValue JSImmediate::oneImmediate() { return makeInt(1); }
+
+    inline bool doubleToBoolean(double value)
+    {
+        return value < 0.0 || value > 0.0;
+    }
+
+    ALWAYS_INLINE bool JSImmediate::toBoolean(JSValue v)
+    {
+        ASSERT(isImmediate(v));
+        return isNumber(v) ? isIntegerNumber(v) ? v != zeroImmediate()
+            : doubleToBoolean(doubleValue(v)) : v == trueImmediate();
+    }
+
+    ALWAYS_INLINE uint32_t JSImmediate::getTruncatedUInt32(JSValue v)
+    {
+        // FIXME: should probably be asserting isPositiveIntegerNumber here.
+        ASSERT(isIntegerNumber(v));
+        return intValue(v);
+    }
+
+    template<typename T>
+    inline JSValue JSImmediate::fromNumberOutsideIntegerRange(T value)
+    {
+        return makeDouble(static_cast<double>(value));
+    }
+
+    ALWAYS_INLINE JSValue JSImmediate::from(char i)
+    {
+        return makeInt(i);
+    }
+
+    ALWAYS_INLINE JSValue JSImmediate::from(signed char i)
+    {
+        return makeInt(i);
+    }
+
+    ALWAYS_INLINE JSValue JSImmediate::from(unsigned char i)
+    {
+        return makeInt(i);
+    }
+
+    ALWAYS_INLINE JSValue JSImmediate::from(short i)
+    {
+        return makeInt(i);
+    }
+
+    ALWAYS_INLINE JSValue JSImmediate::from(unsigned short i)
+    {
+        return makeInt(i);
+    }
+
+    ALWAYS_INLINE JSValue JSImmediate::from(int i)
+    {
+        return makeInt(i);
+    }
+
+    ALWAYS_INLINE JSValue JSImmediate::from(unsigned i)
+    {
+        if (i > maxImmediateUInt)
+            return fromNumberOutsideIntegerRange(i);
+        return makeInt(i);
+    }
+
+    ALWAYS_INLINE JSValue JSImmediate::from(long i)
+    {
+        if ((i < minImmediateInt) | (i > maxImmediateInt))
+            return fromNumberOutsideIntegerRange(i);
+        return makeInt(i);
+    }
+
+    ALWAYS_INLINE JSValue JSImmediate::from(unsigned long i)
+    {
+        if (i > maxImmediateUInt)
+            return fromNumberOutsideIntegerRange(i);
+        return makeInt(i);
+    }
+
+    ALWAYS_INLINE JSValue JSImmediate::from(long long i)
+    {
+        if ((i < minImmediateInt) | (i > maxImmediateInt))
+            return JSValue();
+        return makeInt(static_cast<intptr_t>(i));
+    }
+
+    ALWAYS_INLINE JSValue JSImmediate::from(unsigned long long i)
+    {
+        if (i > maxImmediateUInt)
+            return fromNumberOutsideIntegerRange(i);
+        return makeInt(static_cast<intptr_t>(i));
+    }
+
+    ALWAYS_INLINE JSValue JSImmediate::from(double d)
+    {
+        const int intVal = static_cast<int>(d);
+
+        // Check for data loss from conversion to int.
+        if (intVal != d || (!intVal && signbit(d)))
+            return fromNumberOutsideIntegerRange(d);
+
+        return from(intVal);
+    }
+
+    ALWAYS_INLINE int32_t JSImmediate::getTruncatedInt32(JSValue v)
+    {
+        ASSERT(isIntegerNumber(v));
+        return intValue(v);
+    }
+
+    ALWAYS_INLINE double JSImmediate::toDouble(JSValue v)
+    {
+        ASSERT(isImmediate(v));
+
+        if (isIntegerNumber(v))
+            return intValue(v);
+
+        if (isNumber(v)) {
+            ASSERT(isDouble(v));
+            return doubleValue(v);
+        }
+
+        if (rawValue(v) == FullTagTypeUndefined)
+            return nonInlineNaN();
+
+        ASSERT(JSImmediate::isBoolean(v) || (v == JSImmediate::nullImmediate()));
+        return rawValue(v) >> ExtendedPayloadShift;
+    }
+
+    ALWAYS_INLINE bool JSImmediate::getUInt32(JSValue v, uint32_t& i)
+    {
+        i = uintValue(v);
+        return isPositiveIntegerNumber(v);
+    }
+
+    ALWAYS_INLINE bool JSImmediate::getTruncatedInt32(JSValue v, int32_t& i)
+    {
+        i = intValue(v);
+        return isIntegerNumber(v);
+    }
+
+    ALWAYS_INLINE bool JSImmediate::getTruncatedUInt32(JSValue v, uint32_t& i)
+    {
+        return getUInt32(v, i);
+    }
+
+    inline JSValue::JSValue(JSNullTag)
+    {
+        *this = JSImmediate::nullImmediate();
+    }
+    
+    inline JSValue::JSValue(JSUndefinedTag)
+    {
+        *this = JSImmediate::undefinedImmediate();
+    }
+
+    inline JSValue::JSValue(JSTrueTag)
+    {
+        *this = JSImmediate::trueImmediate();
+    }
+
+    inline JSValue::JSValue(JSFalseTag)
+    {
+        *this = JSImmediate::falseImmediate();
+    }
+
+    inline bool JSValue::isUndefinedOrNull() const
+    {
+        return JSImmediate::isUndefinedOrNull(asValue());
+    }
+
+    inline bool JSValue::isBoolean() const
+    {
+        return JSImmediate::isBoolean(asValue());
+    }
+
+    inline bool JSValue::isTrue() const
+    {
+        return asValue() == JSImmediate::trueImmediate();
+    }
+
+    inline bool JSValue::isFalse() const
+    {
+        return asValue() == JSImmediate::falseImmediate();
+    }
+
+    inline bool JSValue::getBoolean(bool& v) const
+    {
+        if (JSImmediate::isBoolean(asValue())) {
+            v = JSImmediate::toBoolean(asValue());
+            return true;
+        }
+        
+        return false;
+    }
+
+    inline bool JSValue::getBoolean() const
+    {
+        return asValue() == jsBoolean(true);
+    }
+
+    inline bool JSValue::isCell() const
+    {
+        return !JSImmediate::isImmediate(asValue());
+    }
+
+    inline bool JSValue::isInt32() const
+    {
+        return JSImmediate::isIntegerNumber(asValue());
+    }
+
+    inline int32_t JSValue::asInt32() const
+    {
+        ASSERT(isInt32());
+        return JSImmediate::getTruncatedInt32(asValue());
+    }
+
+    inline bool JSValue::isUInt32() const
+    {
+        return JSImmediate::isPositiveIntegerNumber(asValue());
+    }
+
+    inline uint32_t JSValue::asUInt32() const
+    {
+        ASSERT(isUInt32());
+        return JSImmediate::getTruncatedUInt32(asValue());
+    }
+
+} // namespace JSC
+
+#endif // USE(JSVALUE64)
+
+#endif // JSImmediate_h