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1 /*
2  *  Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
3  *  Copyright (C) 2002, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
4  *
5  *  This library is free software; you can redistribute it and/or
6  *  modify it under the terms of the GNU Library General Public
7  *  License as published by the Free Software Foundation; either
8  *  version 2 of the License, or (at your option) any later version.
9  *
10  *  This library is distributed in the hope that it will be useful,
11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  *  Library General Public License for more details.
14  *
15  *  You should have received a copy of the GNU Library General Public License
16  *  along with this library; see the file COPYING.LIB.  If not, write to
17  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
18  *  Boston, MA 02110-1301, USA.
19  *
20  */
21 
22 #ifndef Operations_h
23 #define Operations_h
24 
25 #include "Interpreter.h"
26 #include "JSImmediate.h"
27 #include "JSNumberCell.h"
28 #include "JSString.h"
29 
30 namespace JSC {
31 
32     NEVER_INLINE JSValue throwOutOfMemoryError(ExecState*);
33     NEVER_INLINE JSValue jsAddSlowCase(CallFrame*, JSValue, JSValue);
34     JSValue jsTypeStringForValue(CallFrame*, JSValue);
35     bool jsIsObjectType(JSValue);
36     bool jsIsFunctionType(JSValue);
37 
38     // ECMA 11.9.3
equal(ExecState * exec,JSValue v1,JSValue v2)39     inline bool JSValue::equal(ExecState* exec, JSValue v1, JSValue v2)
40     {
41         if (v1.isInt32() && v2.isInt32())
42             return v1 == v2;
43 
44         return equalSlowCase(exec, v1, v2);
45     }
46 
equalSlowCaseInline(ExecState * exec,JSValue v1,JSValue v2)47     ALWAYS_INLINE bool JSValue::equalSlowCaseInline(ExecState* exec, JSValue v1, JSValue v2)
48     {
49         do {
50             if (v1.isNumber() && v2.isNumber())
51                 return v1.uncheckedGetNumber() == v2.uncheckedGetNumber();
52 
53             bool s1 = v1.isString();
54             bool s2 = v2.isString();
55             if (s1 && s2)
56                 return asString(v1)->value() == asString(v2)->value();
57 
58             if (v1.isUndefinedOrNull()) {
59                 if (v2.isUndefinedOrNull())
60                     return true;
61                 if (!v2.isCell())
62                     return false;
63                 return v2.asCell()->structure()->typeInfo().masqueradesAsUndefined();
64             }
65 
66             if (v2.isUndefinedOrNull()) {
67                 if (!v1.isCell())
68                     return false;
69                 return v1.asCell()->structure()->typeInfo().masqueradesAsUndefined();
70             }
71 
72             if (v1.isObject()) {
73                 if (v2.isObject())
74                     return v1 == v2;
75                 JSValue p1 = v1.toPrimitive(exec);
76                 if (exec->hadException())
77                     return false;
78                 v1 = p1;
79                 if (v1.isInt32() && v2.isInt32())
80                     return v1 == v2;
81                 continue;
82             }
83 
84             if (v2.isObject()) {
85                 JSValue p2 = v2.toPrimitive(exec);
86                 if (exec->hadException())
87                     return false;
88                 v2 = p2;
89                 if (v1.isInt32() && v2.isInt32())
90                     return v1 == v2;
91                 continue;
92             }
93 
94             if (s1 || s2) {
95                 double d1 = v1.toNumber(exec);
96                 double d2 = v2.toNumber(exec);
97                 return d1 == d2;
98             }
99 
100             if (v1.isBoolean()) {
101                 if (v2.isNumber())
102                     return static_cast<double>(v1.getBoolean()) == v2.uncheckedGetNumber();
103             } else if (v2.isBoolean()) {
104                 if (v1.isNumber())
105                     return v1.uncheckedGetNumber() == static_cast<double>(v2.getBoolean());
106             }
107 
108             return v1 == v2;
109         } while (true);
110     }
111 
112     // ECMA 11.9.3
strictEqualSlowCaseInline(JSValue v1,JSValue v2)113     ALWAYS_INLINE bool JSValue::strictEqualSlowCaseInline(JSValue v1, JSValue v2)
114     {
115         ASSERT(v1.isCell() && v2.isCell());
116 
117         if (v1.asCell()->isString() && v2.asCell()->isString())
118             return asString(v1)->value() == asString(v2)->value();
119 
120         return v1 == v2;
121     }
122 
strictEqual(JSValue v1,JSValue v2)123     inline bool JSValue::strictEqual(JSValue v1, JSValue v2)
124     {
125         if (v1.isInt32() && v2.isInt32())
126             return v1 == v2;
127 
128         if (v1.isNumber() && v2.isNumber())
129             return v1.uncheckedGetNumber() == v2.uncheckedGetNumber();
130 
131         if (!v1.isCell() || !v2.isCell())
132             return v1 == v2;
133 
134         return strictEqualSlowCaseInline(v1, v2);
135     }
136 
jsLess(CallFrame * callFrame,JSValue v1,JSValue v2)137     inline bool jsLess(CallFrame* callFrame, JSValue v1, JSValue v2)
138     {
139         if (v1.isInt32() && v2.isInt32())
140             return v1.asInt32() < v2.asInt32();
141 
142         double n1;
143         double n2;
144         if (v1.getNumber(n1) && v2.getNumber(n2))
145             return n1 < n2;
146 
147         JSGlobalData* globalData = &callFrame->globalData();
148         if (isJSString(globalData, v1) && isJSString(globalData, v2))
149             return asString(v1)->value() < asString(v2)->value();
150 
151         JSValue p1;
152         JSValue p2;
153         bool wasNotString1 = v1.getPrimitiveNumber(callFrame, n1, p1);
154         bool wasNotString2 = v2.getPrimitiveNumber(callFrame, n2, p2);
155 
156         if (wasNotString1 | wasNotString2)
157             return n1 < n2;
158 
159         return asString(p1)->value() < asString(p2)->value();
160     }
161 
jsLessEq(CallFrame * callFrame,JSValue v1,JSValue v2)162     inline bool jsLessEq(CallFrame* callFrame, JSValue v1, JSValue v2)
163     {
164         if (v1.isInt32() && v2.isInt32())
165             return v1.asInt32() <= v2.asInt32();
166 
167         double n1;
168         double n2;
169         if (v1.getNumber(n1) && v2.getNumber(n2))
170             return n1 <= n2;
171 
172         JSGlobalData* globalData = &callFrame->globalData();
173         if (isJSString(globalData, v1) && isJSString(globalData, v2))
174             return !(asString(v2)->value() < asString(v1)->value());
175 
176         JSValue p1;
177         JSValue p2;
178         bool wasNotString1 = v1.getPrimitiveNumber(callFrame, n1, p1);
179         bool wasNotString2 = v2.getPrimitiveNumber(callFrame, n2, p2);
180 
181         if (wasNotString1 | wasNotString2)
182             return n1 <= n2;
183 
184         return !(asString(p2)->value() < asString(p1)->value());
185     }
186 
187     // Fast-path choices here are based on frequency data from SunSpider:
188     //    <times> Add case: <t1> <t2>
189     //    ---------------------------
190     //    5626160 Add case: 3 3 (of these, 3637690 are for immediate values)
191     //    247412  Add case: 5 5
192     //    20900   Add case: 5 6
193     //    13962   Add case: 5 3
194     //    4000    Add case: 3 5
195 
jsAdd(CallFrame * callFrame,JSValue v1,JSValue v2)196     ALWAYS_INLINE JSValue jsAdd(CallFrame* callFrame, JSValue v1, JSValue v2)
197     {
198         double left;
199         double right = 0.0;
200 
201         bool rightIsNumber = v2.getNumber(right);
202         if (rightIsNumber && v1.getNumber(left))
203             return jsNumber(callFrame, left + right);
204 
205         bool leftIsString = v1.isString();
206         if (leftIsString && v2.isString()) {
207             RefPtr<UString::Rep> value = concatenate(asString(v1)->value().rep(), asString(v2)->value().rep());
208             if (!value)
209                 return throwOutOfMemoryError(callFrame);
210             return jsString(callFrame, value.release());
211         }
212 
213         if (rightIsNumber & leftIsString) {
214             RefPtr<UString::Rep> value = v2.isInt32() ?
215                 concatenate(asString(v1)->value().rep(), v2.asInt32()) :
216                 concatenate(asString(v1)->value().rep(), right);
217 
218             if (!value)
219                 return throwOutOfMemoryError(callFrame);
220             return jsString(callFrame, value.release());
221         }
222 
223         // All other cases are pretty uncommon
224         return jsAddSlowCase(callFrame, v1, v2);
225     }
226 
countPrototypeChainEntriesAndCheckForProxies(CallFrame * callFrame,JSValue baseValue,const PropertySlot & slot)227     inline size_t countPrototypeChainEntriesAndCheckForProxies(CallFrame* callFrame, JSValue baseValue, const PropertySlot& slot)
228     {
229         JSCell* cell = asCell(baseValue);
230         size_t count = 0;
231 
232         while (slot.slotBase() != cell) {
233             JSValue v = cell->structure()->prototypeForLookup(callFrame);
234 
235             // If we didn't find slotBase in baseValue's prototype chain, then baseValue
236             // must be a proxy for another object.
237 
238             if (v.isNull())
239                 return 0;
240 
241             cell = asCell(v);
242 
243             // Since we're accessing a prototype in a loop, it's a good bet that it
244             // should not be treated as a dictionary.
245             if (cell->structure()->isDictionary())
246                 asObject(cell)->setStructure(Structure::fromDictionaryTransition(cell->structure()));
247 
248             ++count;
249         }
250 
251         ASSERT(count);
252         return count;
253     }
254 
resolveBase(CallFrame * callFrame,Identifier & property,ScopeChainNode * scopeChain)255     ALWAYS_INLINE JSValue resolveBase(CallFrame* callFrame, Identifier& property, ScopeChainNode* scopeChain)
256     {
257         ScopeChainIterator iter = scopeChain->begin();
258         ScopeChainIterator next = iter;
259         ++next;
260         ScopeChainIterator end = scopeChain->end();
261         ASSERT(iter != end);
262 
263         PropertySlot slot;
264         JSObject* base;
265         while (true) {
266             base = *iter;
267             if (next == end || base->getPropertySlot(callFrame, property, slot))
268                 return base;
269 
270             iter = next;
271             ++next;
272         }
273 
274         ASSERT_NOT_REACHED();
275         return JSValue();
276     }
277 
concatenateStrings(CallFrame * callFrame,Register * strings,unsigned count)278     ALWAYS_INLINE JSValue concatenateStrings(CallFrame* callFrame, Register* strings, unsigned count)
279     {
280         ASSERT(count >= 3);
281 
282         // Estimate the amount of space required to hold the entire string.  If all
283         // arguments are strings, we can easily calculate the exact amount of space
284         // required.  For any other arguments, for now let's assume they may require
285         // 11 UChars of storage.  This is enouch to hold any int, and likely is also
286         // reasonable for the other immediates.  We may want to come back and tune
287         // this value at some point.
288         unsigned bufferSize = 0;
289         for (unsigned i = 0; i < count; ++i) {
290             JSValue v = strings[i].jsValue();
291             if (LIKELY(v.isString()))
292                 bufferSize += asString(v)->value().size();
293             else
294                 bufferSize += 11;
295         }
296 
297         // Allocate an output string to store the result.
298         // If the first argument is a String, and if it has the capacity (or can grow
299         // its capacity) to hold the entire result then use this as a base to concatenate
300         // onto.  Otherwise, allocate a new empty output buffer.
301         JSValue firstValue = strings[0].jsValue();
302         RefPtr<UString::Rep> resultRep;
303         if (firstValue.isString() && (resultRep = asString(firstValue)->value().rep())->reserveCapacity(bufferSize)) {
304             // We're going to concatenate onto the first string - remove it from the list of items to be appended.
305             ++strings;
306             --count;
307         } else
308             resultRep = UString::Rep::createEmptyBuffer(bufferSize);
309         UString result(resultRep);
310 
311         // Loop over the openards, writing them into the output buffer.
312         for (unsigned i = 0; i < count; ++i) {
313             JSValue v = strings[i].jsValue();
314             if (LIKELY(v.isString()))
315                 result.append(asString(v)->value());
316             else if (v.isInt32())
317                 result.appendNumeric(v.asInt32());
318             else {
319                 double d;
320                 if (v.getNumber(d))
321                     result.appendNumeric(d);
322                 else
323                     result.append(v.toString(callFrame));
324             }
325         }
326 
327         return jsString(callFrame, result);
328     }
329 
330 } // namespace JSC
331 
332 #endif // Operations_h
333