1/*
2 * Copyright (C) 2015-2017 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 "AbstractModuleRecord.h"
28
29#include "Error.h"
30#include "Interpreter.h"
31#include "JSCInlines.h"
32#include "JSMap.h"
33#include "JSModuleEnvironment.h"
34#include "JSModuleNamespaceObject.h"
35#include "JSModuleRecord.h"
36#include "UnlinkedModuleProgramCodeBlock.h"
37#include "WebAssemblyModuleRecord.h"
38#include <wtf/Optional.h>
39
40namespace JSC {
41namespace AbstractModuleRecordInternal {
42static const bool verbose = false;
43} // namespace AbstractModuleRecordInternal
44
45const ClassInfo AbstractModuleRecord::s_info = { "AbstractModuleRecord", &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(AbstractModuleRecord) };
46
47AbstractModuleRecord::AbstractModuleRecord(VM& vm, Structure* structure, const Identifier& moduleKey)
48 : Base(vm, structure)
49 , m_moduleKey(moduleKey)
50{
51}
52
53void AbstractModuleRecord::destroy(JSCell* cell)
54{
55 AbstractModuleRecord* thisObject = static_cast<AbstractModuleRecord*>(cell);
56 thisObject->AbstractModuleRecord::~AbstractModuleRecord();
57}
58
59void AbstractModuleRecord::finishCreation(ExecState* exec, VM& vm)
60{
61 Base::finishCreation(vm);
62 ASSERT(inherits(vm, info()));
63
64 auto scope = DECLARE_THROW_SCOPE(vm);
65 JSMap* map = JSMap::create(exec, vm, globalObject(vm)->mapStructure());
66 scope.releaseAssertNoException();
67 m_dependenciesMap.set(vm, this, map);
68 putDirect(vm, Identifier::fromString(&vm, "dependenciesMap"_s), m_dependenciesMap.get());
69}
70
71void AbstractModuleRecord::visitChildren(JSCell* cell, SlotVisitor& visitor)
72{
73 AbstractModuleRecord* thisObject = jsCast<AbstractModuleRecord*>(cell);
74 Base::visitChildren(thisObject, visitor);
75 visitor.append(thisObject->m_moduleEnvironment);
76 visitor.append(thisObject->m_moduleNamespaceObject);
77 visitor.append(thisObject->m_dependenciesMap);
78}
79
80void AbstractModuleRecord::appendRequestedModule(const Identifier& moduleName)
81{
82 m_requestedModules.add(moduleName.impl());
83}
84
85void AbstractModuleRecord::addStarExportEntry(const Identifier& moduleName)
86{
87 m_starExportEntries.add(moduleName.impl());
88}
89
90void AbstractModuleRecord::addImportEntry(const ImportEntry& entry)
91{
92 bool isNewEntry = m_importEntries.add(entry.localName.impl(), entry).isNewEntry;
93 ASSERT_UNUSED(isNewEntry, isNewEntry); // This is guaranteed by the parser.
94}
95
96void AbstractModuleRecord::addExportEntry(const ExportEntry& entry)
97{
98 bool isNewEntry = m_exportEntries.add(entry.exportName.impl(), entry).isNewEntry;
99 ASSERT_UNUSED(isNewEntry, isNewEntry); // This is guaranteed by the parser.
100}
101
102auto AbstractModuleRecord::tryGetImportEntry(UniquedStringImpl* localName) -> Optional<ImportEntry>
103{
104 const auto iterator = m_importEntries.find(localName);
105 if (iterator == m_importEntries.end())
106 return WTF::nullopt;
107 return Optional<ImportEntry>(iterator->value);
108}
109
110auto AbstractModuleRecord::tryGetExportEntry(UniquedStringImpl* exportName) -> Optional<ExportEntry>
111{
112 const auto iterator = m_exportEntries.find(exportName);
113 if (iterator == m_exportEntries.end())
114 return WTF::nullopt;
115 return Optional<ExportEntry>(iterator->value);
116}
117
118auto AbstractModuleRecord::ExportEntry::createLocal(const Identifier& exportName, const Identifier& localName) -> ExportEntry
119{
120 return ExportEntry { Type::Local, exportName, Identifier(), Identifier(), localName };
121}
122
123auto AbstractModuleRecord::ExportEntry::createIndirect(const Identifier& exportName, const Identifier& importName, const Identifier& moduleName) -> ExportEntry
124{
125 return ExportEntry { Type::Indirect, exportName, moduleName, importName, Identifier() };
126}
127
128auto AbstractModuleRecord::Resolution::notFound() -> Resolution
129{
130 return Resolution { Type::NotFound, nullptr, Identifier() };
131}
132
133auto AbstractModuleRecord::Resolution::error() -> Resolution
134{
135 return Resolution { Type::Error, nullptr, Identifier() };
136}
137
138auto AbstractModuleRecord::Resolution::ambiguous() -> Resolution
139{
140 return Resolution { Type::Ambiguous, nullptr, Identifier() };
141}
142
143AbstractModuleRecord* AbstractModuleRecord::hostResolveImportedModule(ExecState* exec, const Identifier& moduleName)
144{
145 VM& vm = exec->vm();
146 auto scope = DECLARE_THROW_SCOPE(vm);
147 JSValue moduleNameValue = identifierToJSValue(vm, moduleName);
148 JSValue entry = m_dependenciesMap->JSMap::get(exec, moduleNameValue);
149 RETURN_IF_EXCEPTION(scope, nullptr);
150 RELEASE_AND_RETURN(scope, jsCast<AbstractModuleRecord*>(entry.get(exec, Identifier::fromString(exec, "module"))));
151}
152
153auto AbstractModuleRecord::resolveImport(ExecState* exec, const Identifier& localName) -> Resolution
154{
155 VM& vm = exec->vm();
156 auto scope = DECLARE_THROW_SCOPE(vm);
157
158 Optional<ImportEntry> optionalImportEntry = tryGetImportEntry(localName.impl());
159 if (!optionalImportEntry)
160 return Resolution::notFound();
161
162 const ImportEntry& importEntry = *optionalImportEntry;
163 if (importEntry.type == AbstractModuleRecord::ImportEntryType::Namespace)
164 return Resolution::notFound();
165
166 AbstractModuleRecord* importedModule = hostResolveImportedModule(exec, importEntry.moduleRequest);
167 RETURN_IF_EXCEPTION(scope, Resolution::error());
168 return importedModule->resolveExport(exec, importEntry.importName);
169}
170
171struct AbstractModuleRecord::ResolveQuery {
172 struct Hash {
173 static unsigned hash(const ResolveQuery&);
174 static bool equal(const ResolveQuery&, const ResolveQuery&);
175 static const bool safeToCompareToEmptyOrDeleted = true;
176 };
177 using HashTraits = WTF::CustomHashTraits<ResolveQuery>;
178
179 ResolveQuery(AbstractModuleRecord* moduleRecord, UniquedStringImpl* exportName)
180 : moduleRecord(moduleRecord)
181 , exportName(exportName)
182 {
183 }
184
185 ResolveQuery(AbstractModuleRecord* moduleRecord, const Identifier& exportName)
186 : ResolveQuery(moduleRecord, exportName.impl())
187 {
188 }
189
190 enum EmptyValueTag { EmptyValue };
191 ResolveQuery(EmptyValueTag)
192 {
193 }
194
195 enum DeletedValueTag { DeletedValue };
196 ResolveQuery(DeletedValueTag)
197 : moduleRecord(nullptr)
198 , exportName(WTF::HashTableDeletedValue)
199 {
200 }
201
202 bool isEmptyValue() const
203 {
204 return !exportName;
205 }
206
207 bool isDeletedValue() const
208 {
209 return exportName.isHashTableDeletedValue();
210 }
211
212 void dump(PrintStream& out) const
213 {
214 if (!moduleRecord) {
215 out.print("<empty>");
216 return;
217 }
218 out.print(moduleRecord->moduleKey(), " \"", exportName.get(), "\"");
219 }
220
221 // The module record is not marked from the GC. But these records are reachable from the JSGlobalObject.
222 // So we don't care the reachability to this record.
223 AbstractModuleRecord* moduleRecord;
224 RefPtr<UniquedStringImpl> exportName;
225};
226
227inline unsigned AbstractModuleRecord::ResolveQuery::Hash::hash(const ResolveQuery& query)
228{
229 return WTF::PtrHash<AbstractModuleRecord*>::hash(query.moduleRecord) + IdentifierRepHash::hash(query.exportName);
230}
231
232inline bool AbstractModuleRecord::ResolveQuery::Hash::equal(const ResolveQuery& lhs, const ResolveQuery& rhs)
233{
234 return lhs.moduleRecord == rhs.moduleRecord && lhs.exportName == rhs.exportName;
235}
236
237auto AbstractModuleRecord::tryGetCachedResolution(UniquedStringImpl* exportName) -> Optional<Resolution>
238{
239 const auto iterator = m_resolutionCache.find(exportName);
240 if (iterator == m_resolutionCache.end())
241 return WTF::nullopt;
242 return Optional<Resolution>(iterator->value);
243}
244
245void AbstractModuleRecord::cacheResolution(UniquedStringImpl* exportName, const Resolution& resolution)
246{
247 m_resolutionCache.add(exportName, resolution);
248}
249
250auto AbstractModuleRecord::resolveExportImpl(ExecState* exec, const ResolveQuery& root) -> Resolution
251{
252 VM& vm = exec->vm();
253 auto scope = DECLARE_THROW_SCOPE(vm);
254
255 if (AbstractModuleRecordInternal::verbose)
256 dataLog("Resolving ", root, "\n");
257
258 // https://tc39.github.io/ecma262/#sec-resolveexport
259
260 // How to avoid C++ recursion in this function:
261 // This function avoids C++ recursion of the naive ResolveExport implementation.
262 // Flatten the recursion to the loop with the task queue and frames.
263 //
264 // 1. pendingTasks
265 // We enqueue the recursive resolveExport call to this queue to avoid recursive calls in C++.
266 // The task has 3 types. (1) Query, (2) IndirectFallback and (3) GatherStars.
267 // (1) Query
268 // Querying the resolution to the current module.
269 // (2) IndirectFallback
270 // Examine the result of the indirect export resolution. Only when the indirect export resolution fails,
271 // we look into the star exports. (step 5-a-vi).
272 // (3) GatherStars
273 // Examine the result of the star export resolutions.
274 //
275 // 2. frames
276 // When the spec calls the resolveExport recursively, instead we append the frame
277 // (that holds the result resolution) to the frames and enqueue the task to the pendingTasks.
278 // The entry in the frames means the *local* resolution result of the specific recursive resolveExport.
279 //
280 // We should maintain the local resolution result instead of holding the global resolution result only.
281 // For example,
282 //
283 // star
284 // (1) ---> (2) "Resolve"
285 // |
286 // |
287 // +-> (3) "NotFound"
288 // |
289 // | star
290 // +-> (4) ---> (5) "Resolve" [here]
291 // |
292 // |
293 // +-> (6) "Error"
294 //
295 // Consider the above graph. The numbers represents the modules. Now we are [here].
296 // If we only hold the global resolution result during the resolveExport operation, [here],
297 // we decide the entire result of resolveExport is "Ambiguous", because there are multiple
298 // "Resolve" (in module (2) and (5)). However, this should become "Error" because (6) will
299 // propagate "Error" state to the (4), (4) will become "Error" and then, (1) will become
300 // "Error". We should aggregate the results at the star exports point ((4) and (1)).
301 //
302 // Usually, both "Error" and "Ambiguous" states will throw the syntax error. So except for the content of the
303 // error message, there are no difference. (And if we fix the (6) that raises "Error", next, it will produce
304 // the "Ambiguous" error due to (5). Anyway, user need to fix the both. So which error should be raised at first
305 // doesn't matter so much.
306 //
307 // However, this may become the problem under the module namespace creation.
308 // http://www.ecma-international.org/ecma-262/6.0/#sec-getmodulenamespace
309 // section 15.2.1.18, step 3-d-ii
310 // Here, we distinguish "Ambiguous" and "Error". When "Error" state is produced, we need to throw the propagated error.
311 // But if "Ambiguous" state comes, we just ignore the result.
312 // To follow the requirement strictly, in this implementation, we keep the local resolution result to produce the
313 // correct result under the above complex cases.
314
315 // Caching strategy:
316 // The resolveExport operation is frequently called. So caching results is important.
317 // We observe the following aspects and based on them construct the caching strategy.
318 // Here, we attempt to cache the resolution by constructing the map in module records.
319 // That means Module -> ExportName -> Maybe<Resolution>.
320 // Technically, all the AbstractModuleRecords have the Map<ExportName, Resolution> for caching.
321 //
322 // The important observations are that,
323 //
324 // - *cacheable* means that traversing to this node from a path will produce the same results as starting from this node.
325 //
326 // Here, we define the resovling route. We represent [?] as the module that has the local binding.
327 // And (?) as the module without the local binding.
328 //
329 // @ -> (A) -> (B) -> [C]
330 //
331 // We list the resolving route for each node.
332 //
333 // (A): (A) -> (B) -> [C]
334 // (B): (B) -> [C]
335 // [C]: [C]
336 //
337 // In this case, if we start the tracing from (B), the resolving route becomes (B) -> [C].
338 // So this is the same. At that time, we can say (B) is cacheable in the first tracing.
339 //
340 // - The cache ability of a node depends on the resolving route from this node.
341 //
342 // 1. The starting point is always cacheable.
343 //
344 // 2. A module that has resolved a local binding is always cacheable.
345 //
346 // @ -> (A) -> [B]
347 //
348 // In the above case, we can see the [B] as cacheable.
349 // This is because when starting from [B] node, we immediately resolve with the local binding.
350 // So the resolving route from [B] does not depend on the starting point.
351 //
352 // 3. If we don't follow any star links during the resolution, we can see all the traced nodes are cacheable.
353 //
354 // If there are non star links, it means that there is *no branch* in the module dependency graph.
355 // This *no branch* feature makes all the modules cachable.
356 //
357 // I.e, if we traverse one star link (even if we successfully resolve that star link),
358 // we must still traverse all other star links. I would also explain we don't run into
359 // this when resolving a local/indirect link. When resolving a local/indirect link,
360 // we won't traverse any star links.
361 // And since the module can hold only one local/indirect link for the specific export name (if there
362 // are multiple local/indirect links that has the same export name, it should be syntax error in the
363 // parsing phase.), there is no multiple outgoing links from a module.
364 //
365 // @ -> (A) --> (B) -> [C] -> (D) -> (E) -+
366 // ^ |
367 // | |
368 // +------------------------+
369 //
370 // When starting from @, [C] will be found as the module resolving the given binding.
371 // In this case, (B) can cache this resolution. Since the resolving route is the same to the one when
372 // starting from (B). After caching the above result, we attempt to resolve the same binding from (D).
373 //
374 // @
375 // |
376 // v
377 // @ -> (A) --> (B) -> [C] -> (D) -> (E) -+
378 // ^ |
379 // | |
380 // +------------------------+
381 //
382 // In this case, we can use the (B)'s cached result. And (E) can be cached.
383 //
384 // (E): The resolving route is now (E) -> (B) -> [C]. That is the same when starting from (E).
385 //
386 // No branching makes that the problematic *once-visited* node cannot be seen.
387 // The *once-visited* node makes the resolving route changed since when we see the *once-visited* node,
388 // we stop tracing this.
389 //
390 // If there is no star links and if we look *once-visited* node under no branching graph, *once-visited*
391 // node cannot resolve the requested binding. If the *once-visited* node can resolve the binding, we
392 // should have already finished the resolution before reaching this *once-visited* node.
393 //
394 // 4. Once we follow star links, we should not retrieve the result from the cache and should not cache.
395 //
396 // Star links are only the way to introduce branch.
397 // Once we follow the star links during the resolution, we cannot cache naively.
398 // This is because the cacheability depends on the resolving route. And branching produces the problematic *once-visited*
399 // nodes. Since we don't follow the *once-visited* node, the resolving route from the node becomes different from
400 // the resolving route when starting from this node.
401 //
402 // The following example explains when we should not retrieve the cache and cache the result.
403 //
404 // +----> (D) ------+
405 // | |
406 // | v
407 // (A) *----+----> (B) ---> [C]
408 // ^
409 // |
410 // @
411 //
412 // When starting from (B), we find [C]. In this resolving route, we don't find any star link.
413 // And by definition, (B) and [C] are cachable. (B) is the starting point. And [C] has the local binding.
414 //
415 // +----> (D) ------+
416 // | |
417 // | v
418 // @-> (A) *----+----> (B) ---> [C]
419 //
420 // But when starting from (A), we should not get the value from the cache. Because,
421 //
422 // 1. When looking (D), we reach [C] and make both resolved.
423 // 2. When looking (B), if we retrieved the last cache from (B), (B) becomes resolved.
424 // 3. But actually, (B) is not-found in this trial because (C) is already *once-visited*.
425 // 4. If we accidentally make (B) resolved, (A) becomes ambiguous. But the correct answer is resolved.
426 //
427 // Why is this problem caused? This is because the *once-visited* node makes the result not-found.
428 // In the second trial, (B) -> [C] result is changed from resolved to not-found.
429 //
430 // When does this become a problem? If the status of the *once-visited* node group is resolved,
431 // changing the result to not-found makes the result changed.
432 //
433 // This problem does not happen when we don't see any star link yet. Now, consider the minimum case.
434 //
435 // @-> (A) -> [ some graph ]
436 // ^ |
437 // | |
438 // +------------+
439 //
440 // In (A), we don't see any star link yet. So we can say that all the visited nodes does not have any local
441 // resolution. Because if they had a local/indirect resolution, we should have already finished the tracing.
442 //
443 // And even if the some graph will see the *once-visited* node (in this case, (A)), that does not affect the
444 // result of the resolution. Because even if we follow the link to (A) or not follow the link to (A), the status
445 // of the link is always not-found since (A) does not have any local resolution.
446 // In the above case, we can use the result of the [some graph].
447 //
448 // 5. Once we see star links, even if we have not yet traversed that star link path, we should disable caching.
449 //
450 // Here is the reason why:
451 //
452 // +-------------+
453 // | |
454 // v |
455 // (A) -> (B) -> (C) *-> [E]
456 // * ^
457 // | |
458 // v @
459 // [D]
460 //
461 // In the above case, (C) will be resolved with [D].
462 // (C) will see (A) and (A) gives up in (A) -> (B) -> (C) route. So, (A) will fallback to [D].
463 //
464 // +-------------+
465 // | |
466 // v |
467 // @-> (A) -> (B) -> (C) *-> [E]
468 // *
469 // |
470 // v
471 // [D]
472 //
473 // But in this case, (A) will be resolved with [E] (not [D]).
474 // (C) will attempt to follow the link to (A), but it fails.
475 // So (C) will fallback to the star link and found [E]. In this senario,
476 // (C) is now resolved with [E]'s result.
477 //
478 // The cause of this problem is also the same to 4.
479 // In the latter case, when looking (C), we cannot use the cached result in (C).
480 // Because the cached result of (C) depends on the *once-visited* node (A) and
481 // (A) has the fallback system with the star link.
482 // In the latter trial, we now assume that (A)'s status is not-found.
483 // But, actually, in the former trial, (A)'s status becomes resolved due to the fallback to the [D].
484 //
485 // To summarize the observations.
486 //
487 // 1. The starting point is always cacheable.
488 // 2. A module that has resolved a local binding is always cacheable.
489 // 3. If we don't follow any star links during the resolution, we can see all the traced nodes are cacheable.
490 // 4. Once we follow star links, we should not retrieve the result from the cache and should not cache the result.
491 // 5. Once we see star links, even if we have not yet traversed that star link path, we should disable caching.
492
493 using ResolveSet = WTF::HashSet<ResolveQuery, ResolveQuery::Hash, ResolveQuery::HashTraits>;
494 enum class Type { Query, IndirectFallback, GatherStars };
495 struct Task {
496 ResolveQuery query;
497 Type type;
498 };
499
500 auto typeString = [] (Type type) -> const char* {
501 switch (type) {
502 case Type::Query:
503 return "Query";
504 case Type::IndirectFallback:
505 return "IndirectFallback";
506 case Type::GatherStars:
507 return "GatherStars";
508 }
509 RELEASE_ASSERT_NOT_REACHED();
510 return nullptr;
511 };
512
513 Vector<Task, 8> pendingTasks;
514 ResolveSet resolveSet;
515
516 Vector<Resolution, 8> frames;
517
518 bool foundStarLinks = false;
519
520 frames.append(Resolution::notFound());
521
522 // Call when the query is not resolved in the current module.
523 // It will enqueue the star resolution requests. Return "false" if the error occurs.
524 auto resolveNonLocal = [&](const ResolveQuery& query) -> bool {
525 // https://tc39.github.io/ecma262/#sec-resolveexport
526 // section 15.2.1.16.3, step 6
527 // If the "default" name is not resolved in the current module, we need to throw an error and stop resolution immediately,
528 // Rationale to this error: A default export cannot be provided by an export *.
529 VM& vm = exec->vm();
530 auto scope = DECLARE_THROW_SCOPE(vm);
531 if (query.exportName == vm.propertyNames->defaultKeyword.impl())
532 return false;
533
534 // Enqueue the task to gather the results of the stars.
535 // And append the new Resolution frame to gather the local result of the stars.
536 pendingTasks.append(Task { query, Type::GatherStars });
537 foundStarLinks = true;
538 frames.append(Resolution::notFound());
539
540 // Enqueue the tasks in reverse order.
541 for (auto iterator = query.moduleRecord->starExportEntries().rbegin(), end = query.moduleRecord->starExportEntries().rend(); iterator != end; ++iterator) {
542 const RefPtr<UniquedStringImpl>& starModuleName = *iterator;
543 AbstractModuleRecord* importedModuleRecord = query.moduleRecord->hostResolveImportedModule(exec, Identifier::fromUid(exec, starModuleName.get()));
544 RETURN_IF_EXCEPTION(scope, false);
545 pendingTasks.append(Task { ResolveQuery(importedModuleRecord, query.exportName.get()), Type::Query });
546 }
547 return true;
548 };
549
550 // Return the current resolution value of the top frame.
551 auto currentTop = [&] () -> Resolution& {
552 ASSERT(!frames.isEmpty());
553 return frames.last();
554 };
555
556 // Merge the given resolution to the current resolution value of the top frame.
557 // If there is ambiguity, return "false". When the "false" is returned, we should make the result "ambiguous".
558 auto mergeToCurrentTop = [&] (const Resolution& resolution) -> bool {
559 if (resolution.type == Resolution::Type::NotFound)
560 return true;
561
562 if (currentTop().type == Resolution::Type::NotFound) {
563 currentTop() = resolution;
564 return true;
565 }
566
567 if (currentTop().moduleRecord != resolution.moduleRecord || currentTop().localName != resolution.localName)
568 return false;
569
570 return true;
571 };
572
573 auto cacheResolutionForQuery = [] (const ResolveQuery& query, const Resolution& resolution) {
574 ASSERT(resolution.type == Resolution::Type::Resolved);
575 query.moduleRecord->cacheResolution(query.exportName.get(), resolution);
576 };
577
578 pendingTasks.append(Task { root, Type::Query });
579 while (!pendingTasks.isEmpty()) {
580 const Task task = pendingTasks.takeLast();
581 const ResolveQuery& query = task.query;
582
583 if (AbstractModuleRecordInternal::verbose)
584 dataLog(" ", typeString(task.type), " ", task.query, "\n");
585
586 switch (task.type) {
587 case Type::Query: {
588 AbstractModuleRecord* moduleRecord = query.moduleRecord;
589
590 if (!resolveSet.add(task.query).isNewEntry)
591 continue;
592
593 // 5. Once we see star links, even if we have not yet traversed that star link path, we should disable caching.
594 if (!moduleRecord->starExportEntries().isEmpty())
595 foundStarLinks = true;
596
597 // 4. Once we follow star links, we should not retrieve the result from the cache and should not cache the result.
598 if (!foundStarLinks) {
599 if (Optional<Resolution> cachedResolution = moduleRecord->tryGetCachedResolution(query.exportName.get())) {
600 if (!mergeToCurrentTop(*cachedResolution))
601 return Resolution::ambiguous();
602 continue;
603 }
604 }
605
606 const Optional<ExportEntry> optionalExportEntry = moduleRecord->tryGetExportEntry(query.exportName.get());
607 if (!optionalExportEntry) {
608 // If there is no matched exported binding in the current module,
609 // we need to look into the stars.
610 bool success = resolveNonLocal(task.query);
611 EXCEPTION_ASSERT(!scope.exception() || !success);
612 if (!success)
613 return Resolution::error();
614 continue;
615 }
616
617 const ExportEntry& exportEntry = *optionalExportEntry;
618 switch (exportEntry.type) {
619 case ExportEntry::Type::Local: {
620 ASSERT(!exportEntry.localName.isNull());
621 Resolution resolution { Resolution::Type::Resolved, moduleRecord, exportEntry.localName };
622 // 2. A module that has resolved a local binding is always cacheable.
623 cacheResolutionForQuery(query, resolution);
624 if (!mergeToCurrentTop(resolution))
625 return Resolution::ambiguous();
626 continue;
627 }
628
629 case ExportEntry::Type::Indirect: {
630 AbstractModuleRecord* importedModuleRecord = moduleRecord->hostResolveImportedModule(exec, exportEntry.moduleName);
631 RETURN_IF_EXCEPTION(scope, Resolution::error());
632
633 // When the imported module does not produce any resolved binding, we need to look into the stars in the *current*
634 // module. To do this, we append the `IndirectFallback` task to the task queue.
635 pendingTasks.append(Task { query, Type::IndirectFallback });
636 // And append the new Resolution frame to check the indirect export will be resolved or not.
637 frames.append(Resolution::notFound());
638 pendingTasks.append(Task { ResolveQuery(importedModuleRecord, exportEntry.importName), Type::Query });
639 continue;
640 }
641 }
642 break;
643 }
644
645 case Type::IndirectFallback: {
646 Resolution resolution = frames.takeLast();
647
648 if (resolution.type == Resolution::Type::NotFound) {
649 // Indirect export entry does not produce any resolved binding.
650 // So we will investigate the stars.
651 bool success = resolveNonLocal(task.query);
652 EXCEPTION_ASSERT(!scope.exception() || !success);
653 if (!success)
654 return Resolution::error();
655 continue;
656 }
657
658 ASSERT_WITH_MESSAGE(resolution.type == Resolution::Type::Resolved, "When we see Error and Ambiguous, we immediately return from this loop. So here, only Resolved comes.");
659
660 // 3. If we don't follow any star links during the resolution, we can see all the traced nodes are cacheable.
661 // 4. Once we follow star links, we should not retrieve the result from the cache and should not cache the result.
662 if (!foundStarLinks)
663 cacheResolutionForQuery(query, resolution);
664
665 // If indirect export entry produces Resolved, we should merge it to the upper frame.
666 // And do not investigate the stars of the current module.
667 if (!mergeToCurrentTop(resolution))
668 return Resolution::ambiguous();
669 break;
670 }
671
672 case Type::GatherStars: {
673 Resolution resolution = frames.takeLast();
674 ASSERT_WITH_MESSAGE(resolution.type == Resolution::Type::Resolved || resolution.type == Resolution::Type::NotFound, "When we see Error and Ambiguous, we immediately return from this loop. So here, only Resolved and NotFound comes.");
675
676 // Merge the star resolution to the upper frame.
677 if (!mergeToCurrentTop(resolution))
678 return Resolution::ambiguous();
679 break;
680 }
681 }
682 }
683
684 ASSERT(frames.size() == 1);
685 // 1. The starting point is always cacheable.
686 if (frames[0].type == Resolution::Type::Resolved)
687 cacheResolutionForQuery(root, frames[0]);
688 return frames[0];
689}
690
691auto AbstractModuleRecord::resolveExport(ExecState* exec, const Identifier& exportName) -> Resolution
692{
693 // Look up the cached resolution first before entering the resolving loop, since the loop setup takes some cost.
694 if (Optional<Resolution> cachedResolution = tryGetCachedResolution(exportName.impl()))
695 return *cachedResolution;
696 return resolveExportImpl(exec, ResolveQuery(this, exportName.impl()));
697}
698
699static void getExportedNames(ExecState* exec, AbstractModuleRecord* root, IdentifierSet& exportedNames)
700{
701 VM& vm = exec->vm();
702 auto scope = DECLARE_THROW_SCOPE(vm);
703
704 HashSet<AbstractModuleRecord*> exportStarSet;
705 Vector<AbstractModuleRecord*, 8> pendingModules;
706
707 pendingModules.append(root);
708
709 while (!pendingModules.isEmpty()) {
710 AbstractModuleRecord* moduleRecord = pendingModules.takeLast();
711 if (exportStarSet.contains(moduleRecord))
712 continue;
713 exportStarSet.add(moduleRecord);
714
715 for (const auto& pair : moduleRecord->exportEntries()) {
716 const AbstractModuleRecord::ExportEntry& exportEntry = pair.value;
717 if (moduleRecord == root || vm.propertyNames->defaultKeyword != exportEntry.exportName)
718 exportedNames.add(exportEntry.exportName.impl());
719 }
720
721 for (const auto& starModuleName : moduleRecord->starExportEntries()) {
722 AbstractModuleRecord* requestedModuleRecord = moduleRecord->hostResolveImportedModule(exec, Identifier::fromUid(exec, starModuleName.get()));
723 RETURN_IF_EXCEPTION(scope, void());
724 pendingModules.append(requestedModuleRecord);
725 }
726 }
727}
728
729JSModuleNamespaceObject* AbstractModuleRecord::getModuleNamespace(ExecState* exec)
730{
731 VM& vm = exec->vm();
732 auto scope = DECLARE_THROW_SCOPE(vm);
733
734 // http://www.ecma-international.org/ecma-262/6.0/#sec-getmodulenamespace
735 if (m_moduleNamespaceObject)
736 return m_moduleNamespaceObject.get();
737
738 JSGlobalObject* globalObject = exec->lexicalGlobalObject();
739 IdentifierSet exportedNames;
740 getExportedNames(exec, this, exportedNames);
741 RETURN_IF_EXCEPTION(scope, nullptr);
742
743 Vector<std::pair<Identifier, Resolution>> resolutions;
744 for (auto& name : exportedNames) {
745 Identifier ident = Identifier::fromUid(exec, name.get());
746 const Resolution resolution = resolveExport(exec, ident);
747 RETURN_IF_EXCEPTION(scope, nullptr);
748 switch (resolution.type) {
749 case Resolution::Type::NotFound:
750 throwSyntaxError(exec, scope, makeString("Exported binding name '", String(name.get()), "' is not found."));
751 return nullptr;
752
753 case Resolution::Type::Error:
754 throwSyntaxError(exec, scope, makeString("Exported binding name 'default' cannot be resolved by star export entries."));
755 return nullptr;
756
757 case Resolution::Type::Ambiguous:
758 break;
759
760 case Resolution::Type::Resolved:
761 resolutions.append({ WTFMove(ident), resolution });
762 break;
763 }
764 }
765
766 auto* moduleNamespaceObject = JSModuleNamespaceObject::create(exec, globalObject, globalObject->moduleNamespaceObjectStructure(), this, WTFMove(resolutions));
767 RETURN_IF_EXCEPTION(scope, nullptr);
768 m_moduleNamespaceObject.set(vm, this, moduleNamespaceObject);
769 return moduleNamespaceObject;
770}
771
772void AbstractModuleRecord::link(ExecState* exec, JSValue scriptFetcher)
773{
774 VM& vm = exec->vm();
775 if (auto* jsModuleRecord = jsDynamicCast<JSModuleRecord*>(vm, this))
776 return jsModuleRecord->link(exec, scriptFetcher);
777#if ENABLE(WEBASSEMBLY)
778 if (auto* wasmModuleRecord = jsDynamicCast<WebAssemblyModuleRecord*>(vm, this))
779 return wasmModuleRecord->link(exec, scriptFetcher, nullptr, Wasm::CreationMode::FromModuleLoader);
780#endif
781 RELEASE_ASSERT_NOT_REACHED();
782}
783
784JS_EXPORT_PRIVATE JSValue AbstractModuleRecord::evaluate(ExecState* exec)
785{
786 VM& vm = exec->vm();
787 if (auto* jsModuleRecord = jsDynamicCast<JSModuleRecord*>(vm, this))
788 return jsModuleRecord->evaluate(exec);
789#if ENABLE(WEBASSEMBLY)
790 if (auto* wasmModuleRecord = jsDynamicCast<WebAssemblyModuleRecord*>(vm, this))
791 return wasmModuleRecord->evaluate(exec);
792#endif
793 RELEASE_ASSERT_NOT_REACHED();
794 return jsUndefined();
795}
796
797static String printableName(const RefPtr<UniquedStringImpl>& uid)
798{
799 if (uid->isSymbol())
800 return uid.get();
801 return WTF::makeString("'", String(uid.get()), "'");
802}
803
804static String printableName(const Identifier& ident)
805{
806 return printableName(ident.impl());
807}
808
809void AbstractModuleRecord::dump()
810{
811 dataLog("\nAnalyzing ModuleRecord key(", printableName(m_moduleKey), ")\n");
812
813 dataLog(" Dependencies: ", m_requestedModules.size(), " modules\n");
814 for (const auto& moduleName : m_requestedModules)
815 dataLog(" module(", printableName(moduleName), ")\n");
816
817 dataLog(" Import: ", m_importEntries.size(), " entries\n");
818 for (const auto& pair : m_importEntries) {
819 const ImportEntry& importEntry = pair.value;
820 dataLog(" import(", printableName(importEntry.importName), "), local(", printableName(importEntry.localName), "), module(", printableName(importEntry.moduleRequest), ")\n");
821 }
822
823 dataLog(" Export: ", m_exportEntries.size(), " entries\n");
824 for (const auto& pair : m_exportEntries) {
825 const ExportEntry& exportEntry = pair.value;
826 switch (exportEntry.type) {
827 case ExportEntry::Type::Local:
828 dataLog(" [Local] ", "export(", printableName(exportEntry.exportName), "), local(", printableName(exportEntry.localName), ")\n");
829 break;
830
831 case ExportEntry::Type::Indirect:
832 dataLog(" [Indirect] ", "export(", printableName(exportEntry.exportName), "), import(", printableName(exportEntry.importName), "), module(", printableName(exportEntry.moduleName), ")\n");
833 break;
834 }
835 }
836 for (const auto& moduleName : m_starExportEntries)
837 dataLog(" [Star] module(", printableName(moduleName.get()), ")\n");
838}
839
840} // namespace JSC
841