1/*
2 * Copyright (C) 2013, 2014, 2016 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "DFGLazyJSValue.h"
28
29#if ENABLE(DFG_JIT)
30
31#include "CCallHelpers.h"
32#include "DFGGraph.h"
33#include "JSCInlines.h"
34#include "LinkBuffer.h"
35
36namespace JSC { namespace DFG {
37
38LazyJSValue LazyJSValue::newString(Graph& graph, const String& string)
39{
40 LazyJSValue result;
41 result.m_kind = NewStringImpl;
42 result.u.stringImpl = graph.m_localStrings.add(string).iterator->impl();
43 return result;
44}
45
46JSValue LazyJSValue::getValue(VM& vm) const
47{
48 switch (m_kind) {
49 case KnownValue:
50 return value()->value();
51 case SingleCharacterString:
52 return jsSingleCharacterString(&vm, u.character);
53 case KnownStringImpl:
54 return jsString(&vm, u.stringImpl);
55 case NewStringImpl:
56 return jsString(&vm, AtomicStringImpl::add(u.stringImpl));
57 }
58 RELEASE_ASSERT_NOT_REACHED();
59 return JSValue();
60}
61
62static TriState equalToSingleCharacter(JSValue value, UChar character)
63{
64 if (!value.isString())
65 return FalseTriState;
66
67 JSString* jsString = asString(value);
68 if (jsString->length() != 1)
69 return FalseTriState;
70
71 const StringImpl* string = jsString->tryGetValueImpl();
72 if (!string)
73 return MixedTriState;
74
75 return triState(string->at(0) == character);
76}
77
78static TriState equalToStringImpl(JSValue value, StringImpl* stringImpl)
79{
80 if (!value.isString())
81 return FalseTriState;
82
83 JSString* jsString = asString(value);
84 const StringImpl* string = jsString->tryGetValueImpl();
85 if (!string)
86 return MixedTriState;
87
88 return triState(WTF::equal(stringImpl, string));
89}
90
91const StringImpl* LazyJSValue::tryGetStringImpl(VM& vm) const
92{
93 switch (m_kind) {
94 case KnownStringImpl:
95 case NewStringImpl:
96 return u.stringImpl;
97
98 case KnownValue:
99 if (JSString* string = value()->dynamicCast<JSString*>(vm))
100 return string->tryGetValueImpl();
101 return nullptr;
102
103 default:
104 return nullptr;
105 }
106}
107
108String LazyJSValue::tryGetString(Graph& graph) const
109{
110 switch (m_kind) {
111 case NewStringImpl:
112 return u.stringImpl;
113
114 case SingleCharacterString:
115 return String(&u.character, 1);
116
117 default:
118 if (const StringImpl* string = tryGetStringImpl(graph.m_vm)) {
119 unsigned ginormousStringLength = 10000;
120 if (string->length() > ginormousStringLength)
121 return String();
122
123 auto result = graph.m_copiedStrings.add(string, String());
124 if (result.isNewEntry)
125 result.iterator->value = string->isolatedCopy();
126 return result.iterator->value;
127 }
128
129 return String();
130 }
131}
132
133TriState LazyJSValue::strictEqual(const LazyJSValue& other) const
134{
135 switch (m_kind) {
136 case KnownValue:
137 switch (other.m_kind) {
138 case KnownValue:
139 return JSValue::pureStrictEqual(value()->value(), other.value()->value());
140 case SingleCharacterString:
141 return equalToSingleCharacter(value()->value(), other.character());
142 case KnownStringImpl:
143 case NewStringImpl:
144 return equalToStringImpl(value()->value(), other.stringImpl());
145 }
146 break;
147 case SingleCharacterString:
148 switch (other.m_kind) {
149 case SingleCharacterString:
150 return triState(character() == other.character());
151 case KnownStringImpl:
152 case NewStringImpl:
153 if (other.stringImpl()->length() != 1)
154 return FalseTriState;
155 return triState(other.stringImpl()->at(0) == character());
156 default:
157 return other.strictEqual(*this);
158 }
159 break;
160 case KnownStringImpl:
161 case NewStringImpl:
162 switch (other.m_kind) {
163 case KnownStringImpl:
164 case NewStringImpl:
165 return triState(WTF::equal(stringImpl(), other.stringImpl()));
166 default:
167 return other.strictEqual(*this);
168 }
169 break;
170 }
171 RELEASE_ASSERT_NOT_REACHED();
172 return FalseTriState;
173}
174
175uintptr_t LazyJSValue::switchLookupValue(SwitchKind kind) const
176{
177 // NB. Not every kind of JSValue will be able to give you a switch lookup
178 // value, and this method will assert, or do bad things, if you use it
179 // for a kind of value that can't.
180 switch (m_kind) {
181 case KnownValue:
182 switch (kind) {
183 case SwitchImm:
184 return value()->value().asInt32();
185 case SwitchCell:
186 return bitwise_cast<uintptr_t>(value()->value().asCell());
187 default:
188 RELEASE_ASSERT_NOT_REACHED();
189 return 0;
190 }
191 case SingleCharacterString:
192 switch (kind) {
193 case SwitchChar:
194 return character();
195 default:
196 RELEASE_ASSERT_NOT_REACHED();
197 return 0;
198 }
199 default:
200 RELEASE_ASSERT_NOT_REACHED();
201 return 0;
202 }
203}
204
205void LazyJSValue::emit(CCallHelpers& jit, JSValueRegs result) const
206{
207 if (m_kind == KnownValue) {
208 jit.moveValue(value()->value(), result);
209 return;
210 }
211
212 // It must be some kind of cell.
213#if USE(JSVALUE32_64)
214 jit.move(CCallHelpers::TrustedImm32(JSValue::CellTag), result.tagGPR());
215#endif
216 CCallHelpers::DataLabelPtr label = jit.moveWithPatch(
217 CCallHelpers::TrustedImmPtr(static_cast<size_t>(0xd1e7beeflu)),
218 result.payloadGPR());
219
220 LazyJSValue thisValue = *this;
221
222 // Once we do this, we're committed. Otherwise we leak memory. Note that we call ref/deref
223 // manually to ensure that there is no concurrency shadiness. We are doing something here
224 // that might be rather brutal: transfering ownership of this string.
225 if (m_kind == NewStringImpl)
226 thisValue.u.stringImpl->ref();
227
228 CodeBlock* codeBlock = jit.codeBlock();
229
230 jit.addLinkTask(
231 [codeBlock, label, thisValue] (LinkBuffer& linkBuffer) {
232 JSValue realValue = thisValue.getValue(*codeBlock->vm());
233 RELEASE_ASSERT(realValue.isCell());
234
235 codeBlock->addConstant(realValue);
236
237 if (thisValue.m_kind == NewStringImpl)
238 thisValue.u.stringImpl->deref();
239
240 linkBuffer.patch(label, realValue.asCell());
241 });
242}
243
244void LazyJSValue::dumpInContext(PrintStream& out, DumpContext* context) const
245{
246 switch (m_kind) {
247 case KnownValue:
248 value()->dumpInContext(out, context);
249 return;
250 case SingleCharacterString:
251 out.print("Lazy:SingleCharacterString(");
252 out.printf("%04X", static_cast<unsigned>(character()));
253 out.print(" / ", StringImpl::utf8ForCharacters(&u.character, 1).value(), ")");
254 return;
255 case KnownStringImpl:
256 out.print("Lazy:KnownString(", stringImpl(), ")");
257 return;
258 case NewStringImpl:
259 out.print("Lazy:NewString(", stringImpl(), ")");
260 return;
261 }
262 RELEASE_ASSERT_NOT_REACHED();
263}
264
265void LazyJSValue::dump(PrintStream& out) const
266{
267 dumpInContext(out, 0);
268}
269
270} } // namespace JSC::DFG
271
272#endif // ENABLE(DFG_JIT)
273
274