aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/clang16/lib/Serialization/ModuleManager.cpp
blob: 81dd54692d77e35be1dfef55a8470a89419c3bea (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
//===- ModuleManager.cpp - Module Manager ---------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
//  This file defines the ModuleManager class, which manages a set of loaded
//  modules for the ASTReader.
//
//===----------------------------------------------------------------------===//

#include "clang/Serialization/ModuleManager.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/LLVM.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/ModuleMap.h"
#include "clang/Serialization/GlobalModuleIndex.h"
#include "clang/Serialization/InMemoryModuleCache.h"
#include "clang/Serialization/ModuleFile.h"
#include "clang/Serialization/PCHContainerOperations.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/iterator.h"
#include "llvm/Support/Chrono.h"
#include "llvm/Support/DOTGraphTraits.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/VirtualFileSystem.h"
#include <algorithm>
#include <cassert>
#include <memory>
#include <string>
#include <system_error>

using namespace clang;
using namespace serialization;

ModuleFile *ModuleManager::lookupByFileName(StringRef Name) const {
  auto Entry = FileMgr.getFile(Name, /*OpenFile=*/false,
                               /*CacheFailure=*/false);
  if (Entry)
    return lookup(*Entry);

  return nullptr;
}

ModuleFile *ModuleManager::lookupByModuleName(StringRef Name) const {
  if (const Module *Mod = HeaderSearchInfo.getModuleMap().findModule(Name))
    if (const FileEntry *File = Mod->getASTFile())
      return lookup(File);

  return nullptr;
}

ModuleFile *ModuleManager::lookup(const FileEntry *File) const {
  auto Known = Modules.find(File);
  if (Known == Modules.end())
    return nullptr;

  return Known->second;
}

std::unique_ptr<llvm::MemoryBuffer>
ModuleManager::lookupBuffer(StringRef Name) {
  auto Entry = FileMgr.getFile(Name, /*OpenFile=*/false,
                               /*CacheFailure=*/false);
  if (!Entry)
    return nullptr;
  return std::move(InMemoryBuffers[*Entry]);
}

static bool checkSignature(ASTFileSignature Signature,
                           ASTFileSignature ExpectedSignature,
                           std::string &ErrorStr) {
  if (!ExpectedSignature || Signature == ExpectedSignature)
    return false;

  ErrorStr =
      Signature ? "signature mismatch" : "could not read module signature";
  return true;
}

static void updateModuleImports(ModuleFile &MF, ModuleFile *ImportedBy,
                                SourceLocation ImportLoc) {
  if (ImportedBy) {
    MF.ImportedBy.insert(ImportedBy);
    ImportedBy->Imports.insert(&MF);
  } else {
    if (!MF.DirectlyImported)
      MF.ImportLoc = ImportLoc;

    MF.DirectlyImported = true;
  }
}

ModuleManager::AddModuleResult
ModuleManager::addModule(StringRef FileName, ModuleKind Type,
                         SourceLocation ImportLoc, ModuleFile *ImportedBy,
                         unsigned Generation,
                         off_t ExpectedSize, time_t ExpectedModTime,
                         ASTFileSignature ExpectedSignature,
                         ASTFileSignatureReader ReadSignature,
                         ModuleFile *&Module,
                         std::string &ErrorStr) {
  Module = nullptr;

  // Look for the file entry. This only fails if the expected size or
  // modification time differ.
  OptionalFileEntryRefDegradesToFileEntryPtr Entry;
  if (Type == MK_ExplicitModule || Type == MK_PrebuiltModule) {
    // If we're not expecting to pull this file out of the module cache, it
    // might have a different mtime due to being moved across filesystems in
    // a distributed build. The size must still match, though. (As must the
    // contents, but we can't check that.)
    ExpectedModTime = 0;
  }
  // Note: ExpectedSize and ExpectedModTime will be 0 for MK_ImplicitModule
  // when using an ASTFileSignature.
  if (lookupModuleFile(FileName, ExpectedSize, ExpectedModTime, Entry)) {
    ErrorStr = "module file out of date";
    return OutOfDate;
  }

  if (!Entry && FileName != "-") {
    ErrorStr = "module file not found";
    return Missing;
  }

  // The ModuleManager's use of FileEntry nodes as the keys for its map of
  // loaded modules is less than ideal. Uniqueness for FileEntry nodes is
  // maintained by FileManager, which in turn uses inode numbers on hosts
  // that support that. When coupled with the module cache's proclivity for
  // turning over and deleting stale PCMs, this means entries for different
  // module files can wind up reusing the same underlying inode. When this
  // happens, subsequent accesses to the Modules map will disagree on the
  // ModuleFile associated with a given file. In general, it is not sufficient
  // to resolve this conundrum with a type like FileEntryRef that stores the
  // name of the FileEntry node on first access because of path canonicalization
  // issues. However, the paths constructed for implicit module builds are
  // fully under Clang's control. We *can*, therefore, rely on their structure
  // being consistent across operating systems and across subsequent accesses
  // to the Modules map.
  auto implicitModuleNamesMatch = [](ModuleKind Kind, const ModuleFile *MF,
                                     const FileEntry *Entry) -> bool {
    if (Kind != MK_ImplicitModule)
      return true;
    return Entry->getName() == MF->FileName;
  };

  // Check whether we already loaded this module, before
  if (ModuleFile *ModuleEntry = Modules.lookup(Entry)) {
    if (implicitModuleNamesMatch(Type, ModuleEntry, Entry)) {
      // Check the stored signature.
      if (checkSignature(ModuleEntry->Signature, ExpectedSignature, ErrorStr))
        return OutOfDate;

      Module = ModuleEntry;
      updateModuleImports(*ModuleEntry, ImportedBy, ImportLoc);
      return AlreadyLoaded;
    }
  }

  // Allocate a new module.
  auto NewModule = std::make_unique<ModuleFile>(Type, Generation);
  NewModule->Index = Chain.size();
  NewModule->FileName = FileName.str();
  NewModule->File = Entry;
  NewModule->ImportLoc = ImportLoc;
  NewModule->InputFilesValidationTimestamp = 0;

  if (NewModule->Kind == MK_ImplicitModule) {
    std::string TimestampFilename = NewModule->getTimestampFilename();
    llvm::vfs::Status Status;
    // A cached stat value would be fine as well.
    if (!FileMgr.getNoncachedStatValue(TimestampFilename, Status))
      NewModule->InputFilesValidationTimestamp =
          llvm::sys::toTimeT(Status.getLastModificationTime());
  }

  // Load the contents of the module
  if (std::unique_ptr<llvm::MemoryBuffer> Buffer = lookupBuffer(FileName)) {
    // The buffer was already provided for us.
    NewModule->Buffer = &ModuleCache->addBuiltPCM(FileName, std::move(Buffer));
    // Since the cached buffer is reused, it is safe to close the file
    // descriptor that was opened while stat()ing the PCM in
    // lookupModuleFile() above, it won't be needed any longer.
    Entry->closeFile();
  } else if (llvm::MemoryBuffer *Buffer =
                 getModuleCache().lookupPCM(FileName)) {
    NewModule->Buffer = Buffer;
    // As above, the file descriptor is no longer needed.
    Entry->closeFile();
  } else if (getModuleCache().shouldBuildPCM(FileName)) {
    // Report that the module is out of date, since we tried (and failed) to
    // import it earlier.
    Entry->closeFile();
    return OutOfDate;
  } else {
    // Open the AST file.
    llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> Buf((std::error_code()));
    if (FileName == "-") {
      Buf = llvm::MemoryBuffer::getSTDIN();
    } else {
      // Get a buffer of the file and close the file descriptor when done.
      // The file is volatile because in a parallel build we expect multiple
      // compiler processes to use the same module file rebuilding it if needed.
      //
      // RequiresNullTerminator is false because module files don't need it, and
      // this allows the file to still be mmapped.
      Buf = FileMgr.getBufferForFile(NewModule->File,
                                     /*IsVolatile=*/true,
                                     /*RequiresNullTerminator=*/false);
    }

    if (!Buf) {
      ErrorStr = Buf.getError().message();
      return Missing;
    }

    NewModule->Buffer = &getModuleCache().addPCM(FileName, std::move(*Buf));
  }

  // Initialize the stream.
  NewModule->Data = PCHContainerRdr.ExtractPCH(*NewModule->Buffer);

  // Read the signature eagerly now so that we can check it.  Avoid calling
  // ReadSignature unless there's something to check though.
  if (ExpectedSignature && checkSignature(ReadSignature(NewModule->Data),
                                          ExpectedSignature, ErrorStr))
    return OutOfDate;

  // We're keeping this module.  Store it everywhere.
  Module = Modules[Entry] = NewModule.get();

  updateModuleImports(*NewModule, ImportedBy, ImportLoc);

  if (!NewModule->isModule())
    PCHChain.push_back(NewModule.get());
  if (!ImportedBy)
    Roots.push_back(NewModule.get());

  Chain.push_back(std::move(NewModule));
  return NewlyLoaded;
}

void ModuleManager::removeModules(ModuleIterator First) {
  auto Last = end();
  if (First == Last)
    return;

  // Explicitly clear VisitOrder since we might not notice it is stale.
  VisitOrder.clear();

  // Collect the set of module file pointers that we'll be removing.
  llvm::SmallPtrSet<ModuleFile *, 4> victimSet(
      (llvm::pointer_iterator<ModuleIterator>(First)),
      (llvm::pointer_iterator<ModuleIterator>(Last)));

  auto IsVictim = [&](ModuleFile *MF) {
    return victimSet.count(MF);
  };
  // Remove any references to the now-destroyed modules.
  for (auto I = begin(); I != First; ++I) {
    I->Imports.remove_if(IsVictim);
    I->ImportedBy.remove_if(IsVictim);
  }
  llvm::erase_if(Roots, IsVictim);

  // Remove the modules from the PCH chain.
  for (auto I = First; I != Last; ++I) {
    if (!I->isModule()) {
      PCHChain.erase(llvm::find(PCHChain, &*I), PCHChain.end());
      break;
    }
  }

  // Delete the modules.
  for (ModuleIterator victim = First; victim != Last; ++victim)
    Modules.erase(victim->File);

  Chain.erase(Chain.begin() + (First - begin()), Chain.end());
}

void
ModuleManager::addInMemoryBuffer(StringRef FileName,
                                 std::unique_ptr<llvm::MemoryBuffer> Buffer) {
  const FileEntry *Entry =
      FileMgr.getVirtualFile(FileName, Buffer->getBufferSize(), 0);
  InMemoryBuffers[Entry] = std::move(Buffer);
}

std::unique_ptr<ModuleManager::VisitState> ModuleManager::allocateVisitState() {
  // Fast path: if we have a cached state, use it.
  if (FirstVisitState) {
    auto Result = std::move(FirstVisitState);
    FirstVisitState = std::move(Result->NextState);
    return Result;
  }

  // Allocate and return a new state.
  return std::make_unique<VisitState>(size());
}

void ModuleManager::returnVisitState(std::unique_ptr<VisitState> State) {
  assert(State->NextState == nullptr && "Visited state is in list?");
  State->NextState = std::move(FirstVisitState);
  FirstVisitState = std::move(State);
}

void ModuleManager::setGlobalIndex(GlobalModuleIndex *Index) {
  GlobalIndex = Index;
  if (!GlobalIndex) {
    ModulesInCommonWithGlobalIndex.clear();
    return;
  }

  // Notify the global module index about all of the modules we've already
  // loaded.
  for (ModuleFile &M : *this)
    if (!GlobalIndex->loadedModuleFile(&M))
      ModulesInCommonWithGlobalIndex.push_back(&M);
}

void ModuleManager::moduleFileAccepted(ModuleFile *MF) {
  if (!GlobalIndex || GlobalIndex->loadedModuleFile(MF))
    return;

  ModulesInCommonWithGlobalIndex.push_back(MF);
}

ModuleManager::ModuleManager(FileManager &FileMgr,
                             InMemoryModuleCache &ModuleCache,
                             const PCHContainerReader &PCHContainerRdr,
                             const HeaderSearch &HeaderSearchInfo)
    : FileMgr(FileMgr), ModuleCache(&ModuleCache),
      PCHContainerRdr(PCHContainerRdr), HeaderSearchInfo(HeaderSearchInfo) {}

void ModuleManager::visit(llvm::function_ref<bool(ModuleFile &M)> Visitor,
                          llvm::SmallPtrSetImpl<ModuleFile *> *ModuleFilesHit) {
  // If the visitation order vector is the wrong size, recompute the order.
  if (VisitOrder.size() != Chain.size()) {
    unsigned N = size();
    VisitOrder.clear();
    VisitOrder.reserve(N);

    // Record the number of incoming edges for each module. When we
    // encounter a module with no incoming edges, push it into the queue
    // to seed the queue.
    SmallVector<ModuleFile *, 4> Queue;
    Queue.reserve(N);
    llvm::SmallVector<unsigned, 4> UnusedIncomingEdges;
    UnusedIncomingEdges.resize(size());
    for (ModuleFile &M : llvm::reverse(*this)) {
      unsigned Size = M.ImportedBy.size();
      UnusedIncomingEdges[M.Index] = Size;
      if (!Size)
        Queue.push_back(&M);
    }

    // Traverse the graph, making sure to visit a module before visiting any
    // of its dependencies.
    while (!Queue.empty()) {
      ModuleFile *CurrentModule = Queue.pop_back_val();
      VisitOrder.push_back(CurrentModule);

      // For any module that this module depends on, push it on the
      // stack (if it hasn't already been marked as visited).
      for (ModuleFile *M : llvm::reverse(CurrentModule->Imports)) {
        // Remove our current module as an impediment to visiting the
        // module we depend on. If we were the last unvisited module
        // that depends on this particular module, push it into the
        // queue to be visited.
        unsigned &NumUnusedEdges = UnusedIncomingEdges[M->Index];
        if (NumUnusedEdges && (--NumUnusedEdges == 0))
          Queue.push_back(M);
      }
    }

    assert(VisitOrder.size() == N && "Visitation order is wrong?");

    FirstVisitState = nullptr;
  }

  auto State = allocateVisitState();
  unsigned VisitNumber = State->NextVisitNumber++;

  // If the caller has provided us with a hit-set that came from the global
  // module index, mark every module file in common with the global module
  // index that is *not* in that set as 'visited'.
  if (ModuleFilesHit && !ModulesInCommonWithGlobalIndex.empty()) {
    for (unsigned I = 0, N = ModulesInCommonWithGlobalIndex.size(); I != N; ++I)
    {
      ModuleFile *M = ModulesInCommonWithGlobalIndex[I];
      if (!ModuleFilesHit->count(M))
        State->VisitNumber[M->Index] = VisitNumber;
    }
  }

  for (unsigned I = 0, N = VisitOrder.size(); I != N; ++I) {
    ModuleFile *CurrentModule = VisitOrder[I];
    // Should we skip this module file?
    if (State->VisitNumber[CurrentModule->Index] == VisitNumber)
      continue;

    // Visit the module.
    assert(State->VisitNumber[CurrentModule->Index] == VisitNumber - 1);
    State->VisitNumber[CurrentModule->Index] = VisitNumber;
    if (!Visitor(*CurrentModule))
      continue;

    // The visitor has requested that cut off visitation of any
    // module that the current module depends on. To indicate this
    // behavior, we mark all of the reachable modules as having been visited.
    ModuleFile *NextModule = CurrentModule;
    do {
      // For any module that this module depends on, push it on the
      // stack (if it hasn't already been marked as visited).
      for (llvm::SetVector<ModuleFile *>::iterator
             M = NextModule->Imports.begin(),
             MEnd = NextModule->Imports.end();
           M != MEnd; ++M) {
        if (State->VisitNumber[(*M)->Index] != VisitNumber) {
          State->Stack.push_back(*M);
          State->VisitNumber[(*M)->Index] = VisitNumber;
        }
      }

      if (State->Stack.empty())
        break;

      // Pop the next module off the stack.
      NextModule = State->Stack.pop_back_val();
    } while (true);
  }

  returnVisitState(std::move(State));
}

bool ModuleManager::lookupModuleFile(StringRef FileName, off_t ExpectedSize,
                                     time_t ExpectedModTime,
                                     OptionalFileEntryRef &File) {
  File = std::nullopt;
  if (FileName == "-")
    return false;

  // Open the file immediately to ensure there is no race between stat'ing and
  // opening the file.
  OptionalFileEntryRef FileOrErr =
      expectedToOptional(FileMgr.getFileRef(FileName, /*OpenFile=*/true,
                                            /*CacheFailure=*/false));
  if (!FileOrErr)
    return false;

  File = *FileOrErr;

  if ((ExpectedSize && ExpectedSize != File->getSize()) ||
      (ExpectedModTime && ExpectedModTime != File->getModificationTime()))
    // Do not destroy File, as it may be referenced. If we need to rebuild it,
    // it will be destroyed by removeModules.
    return true;

  return false;
}

#ifndef NDEBUG
namespace llvm {

  template<>
  struct GraphTraits<ModuleManager> {
    using NodeRef = ModuleFile *;
    using ChildIteratorType = llvm::SetVector<ModuleFile *>::const_iterator;
    using nodes_iterator = pointer_iterator<ModuleManager::ModuleConstIterator>;

    static ChildIteratorType child_begin(NodeRef Node) {
      return Node->Imports.begin();
    }

    static ChildIteratorType child_end(NodeRef Node) {
      return Node->Imports.end();
    }

    static nodes_iterator nodes_begin(const ModuleManager &Manager) {
      return nodes_iterator(Manager.begin());
    }

    static nodes_iterator nodes_end(const ModuleManager &Manager) {
      return nodes_iterator(Manager.end());
    }
  };

  template<>
  struct DOTGraphTraits<ModuleManager> : public DefaultDOTGraphTraits {
    explicit DOTGraphTraits(bool IsSimple = false)
        : DefaultDOTGraphTraits(IsSimple) {}

    static bool renderGraphFromBottomUp() { return true; }

    std::string getNodeLabel(ModuleFile *M, const ModuleManager&) {
      return M->ModuleName;
    }
  };

} // namespace llvm

void ModuleManager::viewGraph() {
  llvm::ViewGraph(*this, "Modules");
}
#endif