1/*
2 * Copyright (C) 2012-2019 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 "GetByIdStatus.h"
28
29#include "BytecodeStructs.h"
30#include "CodeBlock.h"
31#include "ComplexGetStatus.h"
32#include "GetterSetterAccessCase.h"
33#include "ICStatusUtils.h"
34#include "InterpreterInlines.h"
35#include "IntrinsicGetterAccessCase.h"
36#include "JSCInlines.h"
37#include "JSScope.h"
38#include "LLIntData.h"
39#include "LowLevelInterpreter.h"
40#include "ModuleNamespaceAccessCase.h"
41#include "PolymorphicAccess.h"
42#include "StructureStubInfo.h"
43#include <wtf/ListDump.h>
44
45namespace JSC {
46namespace DOMJIT {
47class GetterSetter;
48}
49
50bool GetByIdStatus::appendVariant(const GetByIdVariant& variant)
51{
52 return appendICStatusVariant(m_variants, variant);
53}
54
55GetByIdStatus GetByIdStatus::computeFromLLInt(CodeBlock* profiledBlock, unsigned bytecodeIndex, UniquedStringImpl* uid)
56{
57 VM& vm = *profiledBlock->vm();
58
59 auto instruction = profiledBlock->instructions().at(bytecodeIndex);
60
61 StructureID structureID;
62 switch (instruction->opcodeID()) {
63 case op_get_by_id: {
64 auto& metadata = instruction->as<OpGetById>().metadata(profiledBlock);
65 // FIXME: We should not just bail if we see a get_by_id_proto_load.
66 // https://bugs.webkit.org/show_bug.cgi?id=158039
67 if (metadata.m_mode != GetByIdMode::Default)
68 return GetByIdStatus(NoInformation, false);
69 structureID = metadata.m_modeMetadata.defaultMode.structureID;
70 break;
71 }
72 case op_get_by_id_direct:
73 structureID = instruction->as<OpGetByIdDirect>().metadata(profiledBlock).m_structureID;
74 break;
75 case op_try_get_by_id: {
76 // FIXME: We should not just bail if we see a try_get_by_id.
77 // https://bugs.webkit.org/show_bug.cgi?id=158039
78 return GetByIdStatus(NoInformation, false);
79 }
80
81 default: {
82 ASSERT_NOT_REACHED();
83 return GetByIdStatus(NoInformation, false);
84 }
85 }
86
87 if (!structureID)
88 return GetByIdStatus(NoInformation, false);
89
90 Structure* structure = vm.heap.structureIDTable().get(structureID);
91
92 if (structure->takesSlowPathInDFGForImpureProperty())
93 return GetByIdStatus(NoInformation, false);
94
95 unsigned attributes;
96 PropertyOffset offset = structure->getConcurrently(uid, attributes);
97 if (!isValidOffset(offset))
98 return GetByIdStatus(NoInformation, false);
99 if (attributes & PropertyAttribute::CustomAccessorOrValue)
100 return GetByIdStatus(NoInformation, false);
101
102 return GetByIdStatus(Simple, false, GetByIdVariant(StructureSet(structure), offset));
103}
104
105GetByIdStatus GetByIdStatus::computeFor(CodeBlock* profiledBlock, ICStatusMap& map, unsigned bytecodeIndex, UniquedStringImpl* uid, ExitFlag didExit, CallLinkStatus::ExitSiteData callExitSiteData)
106{
107 ConcurrentJSLocker locker(profiledBlock->m_lock);
108
109 GetByIdStatus result;
110
111#if ENABLE(DFG_JIT)
112 result = computeForStubInfoWithoutExitSiteFeedback(
113 locker, profiledBlock, map.get(CodeOrigin(bytecodeIndex)).stubInfo, uid,
114 callExitSiteData);
115
116 if (didExit)
117 return result.slowVersion();
118#else
119 UNUSED_PARAM(map);
120 UNUSED_PARAM(didExit);
121 UNUSED_PARAM(callExitSiteData);
122#endif
123
124 if (!result)
125 return computeFromLLInt(profiledBlock, bytecodeIndex, uid);
126
127 return result;
128}
129
130#if ENABLE(DFG_JIT)
131GetByIdStatus GetByIdStatus::computeForStubInfo(const ConcurrentJSLocker& locker, CodeBlock* profiledBlock, StructureStubInfo* stubInfo, CodeOrigin codeOrigin, UniquedStringImpl* uid)
132{
133 unsigned bytecodeIndex = codeOrigin.bytecodeIndex();
134 GetByIdStatus result = GetByIdStatus::computeForStubInfoWithoutExitSiteFeedback(
135 locker, profiledBlock, stubInfo, uid,
136 CallLinkStatus::computeExitSiteData(profiledBlock, bytecodeIndex));
137
138 if (!result.takesSlowPath() && hasBadCacheExitSite(profiledBlock, bytecodeIndex))
139 return result.slowVersion();
140 return result;
141}
142#endif // ENABLE(DFG_JIT)
143
144#if ENABLE(JIT)
145GetByIdStatus::GetByIdStatus(const ModuleNamespaceAccessCase& accessCase)
146 : m_moduleNamespaceObject(accessCase.moduleNamespaceObject())
147 , m_moduleEnvironment(accessCase.moduleEnvironment())
148 , m_scopeOffset(accessCase.scopeOffset())
149 , m_state(ModuleNamespace)
150 , m_wasSeenInJIT(true)
151{
152}
153
154GetByIdStatus GetByIdStatus::computeForStubInfoWithoutExitSiteFeedback(
155 const ConcurrentJSLocker& locker, CodeBlock* profiledBlock, StructureStubInfo* stubInfo, UniquedStringImpl* uid,
156 CallLinkStatus::ExitSiteData callExitSiteData)
157{
158 StubInfoSummary summary = StructureStubInfo::summary(stubInfo);
159 if (!isInlineable(summary))
160 return GetByIdStatus(summary);
161
162 // Finally figure out if we can derive an access strategy.
163 GetByIdStatus result;
164 result.m_state = Simple;
165 result.m_wasSeenInJIT = true; // This is interesting for bytecode dumping only.
166 switch (stubInfo->cacheType) {
167 case CacheType::Unset:
168 return GetByIdStatus(NoInformation);
169
170 case CacheType::GetByIdSelf: {
171 Structure* structure = stubInfo->u.byIdSelf.baseObjectStructure.get();
172 if (structure->takesSlowPathInDFGForImpureProperty())
173 return GetByIdStatus(JSC::slowVersion(summary));
174 unsigned attributes;
175 GetByIdVariant variant;
176 variant.m_offset = structure->getConcurrently(uid, attributes);
177 if (!isValidOffset(variant.m_offset))
178 return GetByIdStatus(JSC::slowVersion(summary));
179 if (attributes & PropertyAttribute::CustomAccessorOrValue)
180 return GetByIdStatus(JSC::slowVersion(summary));
181
182 variant.m_structureSet.add(structure);
183 bool didAppend = result.appendVariant(variant);
184 ASSERT_UNUSED(didAppend, didAppend);
185 return result;
186 }
187
188 case CacheType::Stub: {
189 PolymorphicAccess* list = stubInfo->u.stub;
190 if (list->size() == 1) {
191 const AccessCase& access = list->at(0);
192 switch (access.type()) {
193 case AccessCase::ModuleNamespaceLoad:
194 return GetByIdStatus(access.as<ModuleNamespaceAccessCase>());
195 default:
196 break;
197 }
198 }
199
200 for (unsigned listIndex = 0; listIndex < list->size(); ++listIndex) {
201 const AccessCase& access = list->at(listIndex);
202 if (access.viaProxy())
203 return GetByIdStatus(JSC::slowVersion(summary));
204
205 if (access.usesPolyProto())
206 return GetByIdStatus(JSC::slowVersion(summary));
207
208 Structure* structure = access.structure();
209 if (!structure) {
210 // The null structure cases arise due to array.length and string.length. We have no way
211 // of creating a GetByIdVariant for those, and we don't really have to since the DFG
212 // handles those cases in FixupPhase using value profiling. That's a bit awkward - we
213 // shouldn't have to use value profiling to discover something that the AccessCase
214 // could have told us. But, it works well enough. So, our only concern here is to not
215 // crash on null structure.
216 return GetByIdStatus(JSC::slowVersion(summary));
217 }
218
219 ComplexGetStatus complexGetStatus = ComplexGetStatus::computeFor(
220 structure, access.conditionSet(), uid);
221
222 switch (complexGetStatus.kind()) {
223 case ComplexGetStatus::ShouldSkip:
224 continue;
225
226 case ComplexGetStatus::TakesSlowPath:
227 return GetByIdStatus(JSC::slowVersion(summary));
228
229 case ComplexGetStatus::Inlineable: {
230 std::unique_ptr<CallLinkStatus> callLinkStatus;
231 JSFunction* intrinsicFunction = nullptr;
232 FunctionPtr<OperationPtrTag> customAccessorGetter;
233 Optional<DOMAttributeAnnotation> domAttribute;
234
235 switch (access.type()) {
236 case AccessCase::Load:
237 case AccessCase::GetGetter:
238 case AccessCase::Miss: {
239 break;
240 }
241 case AccessCase::IntrinsicGetter: {
242 intrinsicFunction = access.as<IntrinsicGetterAccessCase>().intrinsicFunction();
243 break;
244 }
245 case AccessCase::Getter: {
246 callLinkStatus = std::make_unique<CallLinkStatus>();
247 if (CallLinkInfo* callLinkInfo = access.as<GetterSetterAccessCase>().callLinkInfo()) {
248 *callLinkStatus = CallLinkStatus::computeFor(
249 locker, profiledBlock, *callLinkInfo, callExitSiteData);
250 }
251 break;
252 }
253 case AccessCase::CustomAccessorGetter: {
254 customAccessorGetter = access.as<GetterSetterAccessCase>().customAccessor();
255 domAttribute = access.as<GetterSetterAccessCase>().domAttribute();
256 if (!domAttribute)
257 return GetByIdStatus(JSC::slowVersion(summary));
258 result.m_state = Custom;
259 break;
260 }
261 default: {
262 // FIXME: It would be totally sweet to support more of these at some point in the
263 // future. https://bugs.webkit.org/show_bug.cgi?id=133052
264 return GetByIdStatus(JSC::slowVersion(summary));
265 } }
266
267 ASSERT((AccessCase::Miss == access.type()) == (access.offset() == invalidOffset));
268 GetByIdVariant variant(
269 StructureSet(structure), complexGetStatus.offset(),
270 complexGetStatus.conditionSet(), WTFMove(callLinkStatus),
271 intrinsicFunction,
272 customAccessorGetter,
273 domAttribute);
274
275 if (!result.appendVariant(variant))
276 return GetByIdStatus(JSC::slowVersion(summary));
277
278 if (domAttribute) {
279 // Give up when custom accesses are not merged into one.
280 if (result.numVariants() != 1)
281 return GetByIdStatus(JSC::slowVersion(summary));
282 } else {
283 // Give up when custom access and simple access are mixed.
284 if (result.m_state == Custom)
285 return GetByIdStatus(JSC::slowVersion(summary));
286 }
287 break;
288 } }
289 }
290
291 return result;
292 }
293
294 default:
295 return GetByIdStatus(JSC::slowVersion(summary));
296 }
297
298 RELEASE_ASSERT_NOT_REACHED();
299 return GetByIdStatus();
300}
301
302GetByIdStatus GetByIdStatus::computeFor(
303 CodeBlock* profiledBlock, ICStatusMap& baselineMap,
304 ICStatusContextStack& icContextStack, CodeOrigin codeOrigin, UniquedStringImpl* uid)
305{
306 unsigned bytecodeIndex = codeOrigin.bytecodeIndex();
307 CallLinkStatus::ExitSiteData callExitSiteData = CallLinkStatus::computeExitSiteData(profiledBlock, bytecodeIndex);
308 ExitFlag didExit = hasBadCacheExitSite(profiledBlock, bytecodeIndex);
309
310 for (ICStatusContext* context : icContextStack) {
311 ICStatus status = context->get(codeOrigin);
312
313 auto bless = [&] (const GetByIdStatus& result) -> GetByIdStatus {
314 if (!context->isInlined(codeOrigin)) {
315 // Merge with baseline result, which also happens to contain exit data for both
316 // inlined and not-inlined.
317 GetByIdStatus baselineResult = computeFor(
318 profiledBlock, baselineMap, bytecodeIndex, uid, didExit,
319 callExitSiteData);
320 baselineResult.merge(result);
321 return baselineResult;
322 }
323 if (didExit.isSet(ExitFromInlined))
324 return result.slowVersion();
325 return result;
326 };
327
328 if (status.stubInfo) {
329 GetByIdStatus result;
330 {
331 ConcurrentJSLocker locker(context->optimizedCodeBlock->m_lock);
332 result = computeForStubInfoWithoutExitSiteFeedback(
333 locker, context->optimizedCodeBlock, status.stubInfo, uid, callExitSiteData);
334 }
335 if (result.isSet())
336 return bless(result);
337 }
338
339 if (status.getStatus)
340 return bless(*status.getStatus);
341 }
342
343 return computeFor(profiledBlock, baselineMap, bytecodeIndex, uid, didExit, callExitSiteData);
344}
345
346GetByIdStatus GetByIdStatus::computeFor(const StructureSet& set, UniquedStringImpl* uid)
347{
348 // For now we only handle the super simple self access case. We could handle the
349 // prototype case in the future.
350 //
351 // Note that this code is also used for GetByIdDirect since this function only looks
352 // into direct properties. When supporting prototype chains, we should split this for
353 // GetById and GetByIdDirect.
354
355 if (set.isEmpty())
356 return GetByIdStatus();
357
358 if (parseIndex(*uid))
359 return GetByIdStatus(TakesSlowPath);
360
361 GetByIdStatus result;
362 result.m_state = Simple;
363 result.m_wasSeenInJIT = false;
364 for (unsigned i = 0; i < set.size(); ++i) {
365 Structure* structure = set[i];
366 if (structure->typeInfo().overridesGetOwnPropertySlot() && structure->typeInfo().type() != GlobalObjectType)
367 return GetByIdStatus(TakesSlowPath);
368
369 if (!structure->propertyAccessesAreCacheable())
370 return GetByIdStatus(TakesSlowPath);
371
372 unsigned attributes;
373 PropertyOffset offset = structure->getConcurrently(uid, attributes);
374 if (!isValidOffset(offset))
375 return GetByIdStatus(TakesSlowPath); // It's probably a prototype lookup. Give up on life for now, even though we could totally be way smarter about it.
376 if (attributes & PropertyAttribute::Accessor)
377 return GetByIdStatus(MakesCalls); // We could be smarter here, like strength-reducing this to a Call.
378 if (attributes & PropertyAttribute::CustomAccessorOrValue)
379 return GetByIdStatus(TakesSlowPath);
380
381 if (!result.appendVariant(GetByIdVariant(structure, offset)))
382 return GetByIdStatus(TakesSlowPath);
383 }
384
385 return result;
386}
387#endif // ENABLE(JIT)
388
389bool GetByIdStatus::makesCalls() const
390{
391 switch (m_state) {
392 case NoInformation:
393 case TakesSlowPath:
394 case Custom:
395 case ModuleNamespace:
396 return false;
397 case Simple:
398 for (unsigned i = m_variants.size(); i--;) {
399 if (m_variants[i].callLinkStatus())
400 return true;
401 }
402 return false;
403 case MakesCalls:
404 return true;
405 }
406 RELEASE_ASSERT_NOT_REACHED();
407
408 return false;
409}
410
411GetByIdStatus GetByIdStatus::slowVersion() const
412{
413 return GetByIdStatus(makesCalls() ? MakesCalls : TakesSlowPath, wasSeenInJIT());
414}
415
416void GetByIdStatus::merge(const GetByIdStatus& other)
417{
418 if (other.m_state == NoInformation)
419 return;
420
421 auto mergeSlow = [&] () {
422 *this = GetByIdStatus((makesCalls() || other.makesCalls()) ? MakesCalls : TakesSlowPath);
423 };
424
425 switch (m_state) {
426 case NoInformation:
427 *this = other;
428 return;
429
430 case Simple:
431 case Custom:
432 if (m_state != other.m_state)
433 return mergeSlow();
434
435 for (const GetByIdVariant& otherVariant : other.m_variants) {
436 if (!appendVariant(otherVariant))
437 return mergeSlow();
438 }
439 return;
440
441 case ModuleNamespace:
442 if (other.m_state != ModuleNamespace)
443 return mergeSlow();
444
445 if (m_moduleNamespaceObject != other.m_moduleNamespaceObject)
446 return mergeSlow();
447
448 if (m_moduleEnvironment != other.m_moduleEnvironment)
449 return mergeSlow();
450
451 if (m_scopeOffset != other.m_scopeOffset)
452 return mergeSlow();
453
454 return;
455
456 case TakesSlowPath:
457 case MakesCalls:
458 return mergeSlow();
459 }
460
461 RELEASE_ASSERT_NOT_REACHED();
462}
463
464void GetByIdStatus::filter(const StructureSet& set)
465{
466 if (m_state != Simple)
467 return;
468 filterICStatusVariants(m_variants, set);
469 if (m_variants.isEmpty())
470 m_state = NoInformation;
471}
472
473void GetByIdStatus::markIfCheap(SlotVisitor& visitor)
474{
475 for (GetByIdVariant& variant : m_variants)
476 variant.markIfCheap(visitor);
477}
478
479bool GetByIdStatus::finalize(VM& vm)
480{
481 for (GetByIdVariant& variant : m_variants) {
482 if (!variant.finalize(vm))
483 return false;
484 }
485 if (m_moduleNamespaceObject && !vm.heap.isMarked(m_moduleNamespaceObject))
486 return false;
487 if (m_moduleEnvironment && !vm.heap.isMarked(m_moduleEnvironment))
488 return false;
489 return true;
490}
491
492void GetByIdStatus::dump(PrintStream& out) const
493{
494 out.print("(");
495 switch (m_state) {
496 case NoInformation:
497 out.print("NoInformation");
498 break;
499 case Simple:
500 out.print("Simple");
501 break;
502 case Custom:
503 out.print("Custom");
504 break;
505 case ModuleNamespace:
506 out.print("ModuleNamespace");
507 break;
508 case TakesSlowPath:
509 out.print("TakesSlowPath");
510 break;
511 case MakesCalls:
512 out.print("MakesCalls");
513 break;
514 }
515 out.print(", ", listDump(m_variants), ", seenInJIT = ", m_wasSeenInJIT, ")");
516}
517
518} // namespace JSC
519
520