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1 | /* | |
2 | * Copyright (C) 2012, 2013 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 "DFGVariableEventStream.h" | |
28 | ||
29 | #if ENABLE(DFG_JIT) | |
30 | ||
31 | #include "CodeBlock.h" | |
32 | #include "DFGValueSource.h" | |
33 | #include "Operations.h" | |
34 | #include <wtf/DataLog.h> | |
35 | #include <wtf/HashMap.h> | |
36 | ||
37 | namespace JSC { namespace DFG { | |
38 | ||
39 | void VariableEventStream::logEvent(const VariableEvent& event) | |
40 | { | |
41 | dataLogF("seq#%u:", static_cast<unsigned>(size())); | |
42 | event.dump(WTF::dataFile()); | |
43 | dataLogF(" "); | |
44 | } | |
45 | ||
46 | namespace { | |
47 | ||
48 | struct MinifiedGenerationInfo { | |
49 | bool filled; // true -> in gpr/fpr/pair, false -> spilled | |
50 | VariableRepresentation u; | |
51 | DataFormat format; | |
52 | ||
53 | MinifiedGenerationInfo() | |
54 | : format(DataFormatNone) | |
55 | { | |
56 | } | |
57 | ||
58 | void update(const VariableEvent& event) | |
59 | { | |
60 | switch (event.kind()) { | |
61 | case BirthToFill: | |
62 | case Fill: | |
63 | filled = true; | |
64 | break; | |
65 | case BirthToSpill: | |
66 | case Spill: | |
67 | filled = false; | |
68 | break; | |
69 | case Death: | |
70 | format = DataFormatNone; | |
71 | return; | |
72 | default: | |
73 | return; | |
74 | } | |
75 | ||
76 | u = event.variableRepresentation(); | |
77 | format = event.dataFormat(); | |
78 | } | |
79 | }; | |
80 | ||
81 | } // namespace | |
82 | ||
83 | bool VariableEventStream::tryToSetConstantRecovery(ValueRecovery& recovery, CodeBlock* codeBlock, MinifiedNode* node) const | |
84 | { | |
85 | if (!node) | |
86 | return false; | |
87 | ||
88 | if (node->hasConstantNumber()) { | |
89 | recovery = ValueRecovery::constant( | |
90 | codeBlock->constantRegister( | |
91 | FirstConstantRegisterIndex + node->constantNumber()).get()); | |
92 | return true; | |
93 | } | |
94 | ||
95 | if (node->hasWeakConstant()) { | |
96 | recovery = ValueRecovery::constant(node->weakConstant()); | |
97 | return true; | |
98 | } | |
99 | ||
100 | if (node->op() == PhantomArguments) { | |
101 | recovery = ValueRecovery::argumentsThatWereNotCreated(); | |
102 | return true; | |
103 | } | |
104 | ||
105 | return false; | |
106 | } | |
107 | ||
108 | void VariableEventStream::reconstruct( | |
109 | CodeBlock* codeBlock, CodeOrigin codeOrigin, MinifiedGraph& graph, | |
110 | unsigned index, Operands<ValueRecovery>& valueRecoveries) const | |
111 | { | |
112 | ASSERT(codeBlock->getJITType() == JITCode::DFGJIT); | |
113 | CodeBlock* baselineCodeBlock = codeBlock->baselineVersion(); | |
114 | ||
115 | unsigned numVariables; | |
116 | if (codeOrigin.inlineCallFrame) | |
117 | numVariables = baselineCodeBlockForInlineCallFrame(codeOrigin.inlineCallFrame)->m_numCalleeRegisters + codeOrigin.inlineCallFrame->stackOffset; | |
118 | else | |
119 | numVariables = baselineCodeBlock->m_numCalleeRegisters; | |
120 | ||
121 | // Crazy special case: if we're at index == 0 then this must be an argument check | |
122 | // failure, in which case all variables are already set up. The recoveries should | |
123 | // reflect this. | |
124 | if (!index) { | |
125 | valueRecoveries = Operands<ValueRecovery>(codeBlock->numParameters(), numVariables); | |
126 | for (size_t i = 0; i < valueRecoveries.size(); ++i) | |
127 | valueRecoveries[i] = ValueRecovery::alreadyInJSStack(); | |
128 | return; | |
129 | } | |
130 | ||
131 | // Step 1: Find the last checkpoint, and figure out the number of virtual registers as we go. | |
132 | unsigned startIndex = index - 1; | |
133 | while (at(startIndex).kind() != Reset) | |
134 | startIndex--; | |
135 | ||
136 | #if DFG_ENABLE(DEBUG_VERBOSE) | |
137 | dataLogF("Computing OSR exit recoveries starting at seq#%u.\n", startIndex); | |
138 | #endif | |
139 | ||
140 | // Step 2: Create a mock-up of the DFG's state and execute the events. | |
141 | Operands<ValueSource> operandSources(codeBlock->numParameters(), numVariables); | |
142 | HashMap<MinifiedID, MinifiedGenerationInfo> generationInfos; | |
143 | for (unsigned i = startIndex; i < index; ++i) { | |
144 | const VariableEvent& event = at(i); | |
145 | switch (event.kind()) { | |
146 | case Reset: | |
147 | // nothing to do. | |
148 | break; | |
149 | case BirthToFill: | |
150 | case BirthToSpill: { | |
151 | MinifiedGenerationInfo info; | |
152 | info.update(event); | |
153 | generationInfos.add(event.id(), info); | |
154 | break; | |
155 | } | |
156 | case Fill: | |
157 | case Spill: | |
158 | case Death: { | |
159 | HashMap<MinifiedID, MinifiedGenerationInfo>::iterator iter = generationInfos.find(event.id()); | |
160 | ASSERT(iter != generationInfos.end()); | |
161 | iter->value.update(event); | |
162 | break; | |
163 | } | |
164 | case MovHintEvent: | |
165 | if (operandSources.hasOperand(event.operand())) | |
166 | operandSources.setOperand(event.operand(), ValueSource(event.id())); | |
167 | break; | |
168 | case SetLocalEvent: | |
169 | if (operandSources.hasOperand(event.operand())) | |
170 | operandSources.setOperand(event.operand(), ValueSource::forDataFormat(event.dataFormat())); | |
171 | break; | |
172 | default: | |
173 | RELEASE_ASSERT_NOT_REACHED(); | |
174 | break; | |
175 | } | |
176 | } | |
177 | ||
178 | // Step 3: Compute value recoveries! | |
179 | valueRecoveries = Operands<ValueRecovery>(codeBlock->numParameters(), numVariables); | |
180 | for (unsigned i = 0; i < operandSources.size(); ++i) { | |
181 | ValueSource& source = operandSources[i]; | |
182 | if (source.isTriviallyRecoverable()) { | |
183 | valueRecoveries[i] = source.valueRecovery(); | |
184 | continue; | |
185 | } | |
186 | ||
187 | ASSERT(source.kind() == HaveNode); | |
188 | MinifiedNode* node = graph.at(source.id()); | |
189 | if (tryToSetConstantRecovery(valueRecoveries[i], codeBlock, node)) | |
190 | continue; | |
191 | ||
192 | MinifiedGenerationInfo info = generationInfos.get(source.id()); | |
193 | if (info.format == DataFormatNone) { | |
194 | // Try to see if there is an alternate node that would contain the value we want. | |
195 | // There are four possibilities: | |
196 | // | |
197 | // Int32ToDouble: We can use this in place of the original node, but | |
198 | // we'd rather not; so we use it only if it is the only remaining | |
199 | // live version. | |
200 | // | |
201 | // ValueToInt32: If the only remaining live version of the value is | |
202 | // ValueToInt32, then we can use it. | |
203 | // | |
204 | // UInt32ToNumber: If the only live version of the value is a UInt32ToNumber | |
205 | // then the only remaining uses are ones that want a properly formed number | |
206 | // rather than a UInt32 intermediate. | |
207 | // | |
208 | // DoubleAsInt32: Same as UInt32ToNumber. | |
209 | // | |
210 | // The reverse of the above: This node could be a UInt32ToNumber, but its | |
211 | // alternative is still alive. This means that the only remaining uses of | |
212 | // the number would be fine with a UInt32 intermediate. | |
213 | ||
214 | bool found = false; | |
215 | ||
216 | if (node && node->op() == UInt32ToNumber) { | |
217 | MinifiedID id = node->child1(); | |
218 | if (tryToSetConstantRecovery(valueRecoveries[i], codeBlock, graph.at(id))) | |
219 | continue; | |
220 | info = generationInfos.get(id); | |
221 | if (info.format != DataFormatNone) | |
222 | found = true; | |
223 | } | |
224 | ||
225 | if (!found) { | |
226 | MinifiedID int32ToDoubleID; | |
227 | MinifiedID valueToInt32ID; | |
228 | MinifiedID uint32ToNumberID; | |
229 | MinifiedID doubleAsInt32ID; | |
230 | ||
231 | HashMap<MinifiedID, MinifiedGenerationInfo>::iterator iter = generationInfos.begin(); | |
232 | HashMap<MinifiedID, MinifiedGenerationInfo>::iterator end = generationInfos.end(); | |
233 | for (; iter != end; ++iter) { | |
234 | MinifiedID id = iter->key; | |
235 | node = graph.at(id); | |
236 | if (!node) | |
237 | continue; | |
238 | if (!node->hasChild1()) | |
239 | continue; | |
240 | if (node->child1() != source.id()) | |
241 | continue; | |
242 | if (iter->value.format == DataFormatNone) | |
243 | continue; | |
244 | switch (node->op()) { | |
245 | case Int32ToDouble: | |
246 | case ForwardInt32ToDouble: | |
247 | int32ToDoubleID = id; | |
248 | break; | |
249 | case ValueToInt32: | |
250 | valueToInt32ID = id; | |
251 | break; | |
252 | case UInt32ToNumber: | |
253 | uint32ToNumberID = id; | |
254 | break; | |
255 | case DoubleAsInt32: | |
256 | doubleAsInt32ID = id; | |
257 | break; | |
258 | default: | |
259 | break; | |
260 | } | |
261 | } | |
262 | ||
263 | MinifiedID idToUse; | |
264 | if (!!doubleAsInt32ID) | |
265 | idToUse = doubleAsInt32ID; | |
266 | else if (!!int32ToDoubleID) | |
267 | idToUse = int32ToDoubleID; | |
268 | else if (!!valueToInt32ID) | |
269 | idToUse = valueToInt32ID; | |
270 | else if (!!uint32ToNumberID) | |
271 | idToUse = uint32ToNumberID; | |
272 | ||
273 | if (!!idToUse) { | |
274 | info = generationInfos.get(idToUse); | |
275 | ASSERT(info.format != DataFormatNone); | |
276 | found = true; | |
277 | } | |
278 | } | |
279 | ||
280 | if (!found) { | |
281 | valueRecoveries[i] = ValueRecovery::constant(jsUndefined()); | |
282 | continue; | |
283 | } | |
284 | } | |
285 | ||
286 | ASSERT(info.format != DataFormatNone); | |
287 | ||
288 | if (info.filled) { | |
289 | if (info.format == DataFormatDouble) { | |
290 | valueRecoveries[i] = ValueRecovery::inFPR(info.u.fpr); | |
291 | continue; | |
292 | } | |
293 | #if USE(JSVALUE32_64) | |
294 | if (info.format & DataFormatJS) { | |
295 | valueRecoveries[i] = ValueRecovery::inPair(info.u.pair.tagGPR, info.u.pair.payloadGPR); | |
296 | continue; | |
297 | } | |
298 | #endif | |
299 | valueRecoveries[i] = ValueRecovery::inGPR(info.u.gpr, info.format); | |
300 | continue; | |
301 | } | |
302 | ||
303 | valueRecoveries[i] = | |
304 | ValueRecovery::displacedInJSStack(static_cast<VirtualRegister>(info.u.virtualReg), info.format); | |
305 | } | |
306 | ||
307 | // Step 4: Make sure that for locals that coincide with true call frame headers, the exit compiler knows | |
308 | // that those values don't have to be recovered. Signal this by using ValueRecovery::alreadyInJSStack() | |
309 | for (InlineCallFrame* inlineCallFrame = codeOrigin.inlineCallFrame; inlineCallFrame; inlineCallFrame = inlineCallFrame->caller.inlineCallFrame) { | |
310 | for (unsigned i = JSStack::CallFrameHeaderSize; i--;) | |
311 | valueRecoveries.setLocal(inlineCallFrame->stackOffset - i - 1, ValueRecovery::alreadyInJSStack()); | |
312 | } | |
313 | } | |
314 | ||
315 | } } // namespace JSC::DFG | |
316 | ||
317 | #endif // ENABLE(DFG_JIT) | |
318 |