1//===- Module.h - Describe a module -----------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9/// \file
10/// Defines the clang::Module class, which describes a module in the
11/// source code.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CLANG_BASIC_MODULE_H
16#define LLVM_CLANG_BASIC_MODULE_H
17
18#include "clang/Basic/FileManager.h"
19#include "clang/Basic/SourceLocation.h"
20#include "llvm/ADT/ArrayRef.h"
21#include "llvm/ADT/DenseSet.h"
22#include "llvm/ADT/Optional.h"
23#include "llvm/ADT/PointerIntPair.h"
24#include "llvm/ADT/PointerUnion.h"
25#include "llvm/ADT/SetVector.h"
26#include "llvm/ADT/SmallVector.h"
27#include "llvm/ADT/STLExtras.h"
28#include "llvm/ADT/StringMap.h"
29#include "llvm/ADT/StringRef.h"
30#include "llvm/ADT/iterator_range.h"
31#include <array>
32#include <cassert>
33#include <cstdint>
34#include <ctime>
35#include <string>
36#include <utility>
37#include <vector>
38
39namespace llvm {
40
41class raw_ostream;
42
43} // namespace llvm
44
45namespace clang {
46
47class LangOptions;
48class TargetInfo;
49
50/// Describes the name of a module.
51using ModuleId = SmallVector<std::pair<std::string, SourceLocation>, 2>;
52
53/// The signature of a module, which is a hash of the AST content.
54struct ASTFileSignature : std::array<uint32_t, 5> {
55 ASTFileSignature(std::array<uint32_t, 5> S = {{0}})
56 : std::array<uint32_t, 5>(std::move(S)) {}
57
58 explicit operator bool() const {
59 return *this != std::array<uint32_t, 5>({{0}});
60 }
61};
62
63/// Describes a module or submodule.
64class Module {
65public:
66 /// The name of this module.
67 std::string Name;
68
69 /// The location of the module definition.
70 SourceLocation DefinitionLoc;
71
72 enum ModuleKind {
73 /// This is a module that was defined by a module map and built out
74 /// of header files.
75 ModuleMapModule,
76
77 /// This is a C++ Modules TS module interface unit.
78 ModuleInterfaceUnit,
79
80 /// This is a fragment of the global module within some C++ Modules
81 /// TS module.
82 GlobalModuleFragment,
83 };
84
85 /// The kind of this module.
86 ModuleKind Kind = ModuleMapModule;
87
88 /// The parent of this module. This will be NULL for the top-level
89 /// module.
90 Module *Parent;
91
92 /// The build directory of this module. This is the directory in
93 /// which the module is notionally built, and relative to which its headers
94 /// are found.
95 const DirectoryEntry *Directory = nullptr;
96
97 /// The presumed file name for the module map defining this module.
98 /// Only non-empty when building from preprocessed source.
99 std::string PresumedModuleMapFile;
100
101 /// The umbrella header or directory.
102 llvm::PointerUnion<const DirectoryEntry *, const FileEntry *> Umbrella;
103
104 /// The module signature.
105 ASTFileSignature Signature;
106
107 /// The name of the umbrella entry, as written in the module map.
108 std::string UmbrellaAsWritten;
109
110 /// The module through which entities defined in this module will
111 /// eventually be exposed, for use in "private" modules.
112 std::string ExportAsModule;
113
114private:
115 /// The submodules of this module, indexed by name.
116 std::vector<Module *> SubModules;
117
118 /// A mapping from the submodule name to the index into the
119 /// \c SubModules vector at which that submodule resides.
120 llvm::StringMap<unsigned> SubModuleIndex;
121
122 /// The AST file if this is a top-level module which has a
123 /// corresponding serialized AST file, or null otherwise.
124 const FileEntry *ASTFile = nullptr;
125
126 /// The top-level headers associated with this module.
127 llvm::SmallSetVector<const FileEntry *, 2> TopHeaders;
128
129 /// top-level header filenames that aren't resolved to FileEntries yet.
130 std::vector<std::string> TopHeaderNames;
131
132 /// Cache of modules visible to lookup in this module.
133 mutable llvm::DenseSet<const Module*> VisibleModulesCache;
134
135 /// The ID used when referencing this module within a VisibleModuleSet.
136 unsigned VisibilityID;
137
138public:
139 enum HeaderKind {
140 HK_Normal,
141 HK_Textual,
142 HK_Private,
143 HK_PrivateTextual,
144 HK_Excluded
145 };
146 static const int NumHeaderKinds = HK_Excluded + 1;
147
148 /// Information about a header directive as found in the module map
149 /// file.
150 struct Header {
151 std::string NameAsWritten;
152 const FileEntry *Entry;
153
154 explicit operator bool() { return Entry; }
155 };
156
157 /// Information about a directory name as found in the module map
158 /// file.
159 struct DirectoryName {
160 std::string NameAsWritten;
161 const DirectoryEntry *Entry;
162
163 explicit operator bool() { return Entry; }
164 };
165
166 /// The headers that are part of this module.
167 SmallVector<Header, 2> Headers[5];
168
169 /// Stored information about a header directive that was found in the
170 /// module map file but has not been resolved to a file.
171 struct UnresolvedHeaderDirective {
172 HeaderKind Kind = HK_Normal;
173 SourceLocation FileNameLoc;
174 std::string FileName;
175 bool IsUmbrella = false;
176 bool HasBuiltinHeader = false;
177 Optional<off_t> Size;
178 Optional<time_t> ModTime;
179 };
180
181 /// Headers that are mentioned in the module map file but that we have not
182 /// yet attempted to resolve to a file on the file system.
183 SmallVector<UnresolvedHeaderDirective, 1> UnresolvedHeaders;
184
185 /// Headers that are mentioned in the module map file but could not be
186 /// found on the file system.
187 SmallVector<UnresolvedHeaderDirective, 1> MissingHeaders;
188
189 /// An individual requirement: a feature name and a flag indicating
190 /// the required state of that feature.
191 using Requirement = std::pair<std::string, bool>;
192
193 /// The set of language features required to use this module.
194 ///
195 /// If any of these requirements are not available, the \c IsAvailable bit
196 /// will be false to indicate that this (sub)module is not available.
197 SmallVector<Requirement, 2> Requirements;
198
199 /// A module with the same name that shadows this module.
200 Module *ShadowingModule = nullptr;
201
202 /// Whether this module is missing a feature from \c Requirements.
203 unsigned IsMissingRequirement : 1;
204
205 /// Whether we tried and failed to load a module file for this module.
206 unsigned HasIncompatibleModuleFile : 1;
207
208 /// Whether this module is available in the current translation unit.
209 ///
210 /// If the module is missing headers or does not meet all requirements then
211 /// this bit will be 0.
212 unsigned IsAvailable : 1;
213
214 /// Whether this module was loaded from a module file.
215 unsigned IsFromModuleFile : 1;
216
217 /// Whether this is a framework module.
218 unsigned IsFramework : 1;
219
220 /// Whether this is an explicit submodule.
221 unsigned IsExplicit : 1;
222
223 /// Whether this is a "system" module (which assumes that all
224 /// headers in it are system headers).
225 unsigned IsSystem : 1;
226
227 /// Whether this is an 'extern "C"' module (which implicitly puts all
228 /// headers in it within an 'extern "C"' block, and allows the module to be
229 /// imported within such a block).
230 unsigned IsExternC : 1;
231
232 /// Whether this is an inferred submodule (module * { ... }).
233 unsigned IsInferred : 1;
234
235 /// Whether we should infer submodules for this module based on
236 /// the headers.
237 ///
238 /// Submodules can only be inferred for modules with an umbrella header.
239 unsigned InferSubmodules : 1;
240
241 /// Whether, when inferring submodules, the inferred submodules
242 /// should be explicit.
243 unsigned InferExplicitSubmodules : 1;
244
245 /// Whether, when inferring submodules, the inferr submodules should
246 /// export all modules they import (e.g., the equivalent of "export *").
247 unsigned InferExportWildcard : 1;
248
249 /// Whether the set of configuration macros is exhaustive.
250 ///
251 /// When the set of configuration macros is exhaustive, meaning
252 /// that no identifier not in this list should affect how the module is
253 /// built.
254 unsigned ConfigMacrosExhaustive : 1;
255
256 /// Whether files in this module can only include non-modular headers
257 /// and headers from used modules.
258 unsigned NoUndeclaredIncludes : 1;
259
260 /// Whether this module came from a "private" module map, found next
261 /// to a regular (public) module map.
262 unsigned ModuleMapIsPrivate : 1;
263
264 /// Describes the visibility of the various names within a
265 /// particular module.
266 enum NameVisibilityKind {
267 /// All of the names in this module are hidden.
268 Hidden,
269 /// All of the names in this module are visible.
270 AllVisible
271 };
272
273 /// The visibility of names within this particular module.
274 NameVisibilityKind NameVisibility;
275
276 /// The location of the inferred submodule.
277 SourceLocation InferredSubmoduleLoc;
278
279 /// The set of modules imported by this module, and on which this
280 /// module depends.
281 llvm::SmallSetVector<Module *, 2> Imports;
282
283 /// Describes an exported module.
284 ///
285 /// The pointer is the module being re-exported, while the bit will be true
286 /// to indicate that this is a wildcard export.
287 using ExportDecl = llvm::PointerIntPair<Module *, 1, bool>;
288
289 /// The set of export declarations.
290 SmallVector<ExportDecl, 2> Exports;
291
292 /// Describes an exported module that has not yet been resolved
293 /// (perhaps because the module it refers to has not yet been loaded).
294 struct UnresolvedExportDecl {
295 /// The location of the 'export' keyword in the module map file.
296 SourceLocation ExportLoc;
297
298 /// The name of the module.
299 ModuleId Id;
300
301 /// Whether this export declaration ends in a wildcard, indicating
302 /// that all of its submodules should be exported (rather than the named
303 /// module itself).
304 bool Wildcard;
305 };
306
307 /// The set of export declarations that have yet to be resolved.
308 SmallVector<UnresolvedExportDecl, 2> UnresolvedExports;
309
310 /// The directly used modules.
311 SmallVector<Module *, 2> DirectUses;
312
313 /// The set of use declarations that have yet to be resolved.
314 SmallVector<ModuleId, 2> UnresolvedDirectUses;
315
316 /// A library or framework to link against when an entity from this
317 /// module is used.
318 struct LinkLibrary {
319 LinkLibrary() = default;
320 LinkLibrary(const std::string &Library, bool IsFramework)
321 : Library(Library), IsFramework(IsFramework) {}
322
323 /// The library to link against.
324 ///
325 /// This will typically be a library or framework name, but can also
326 /// be an absolute path to the library or framework.
327 std::string Library;
328
329 /// Whether this is a framework rather than a library.
330 bool IsFramework = false;
331 };
332
333 /// The set of libraries or frameworks to link against when
334 /// an entity from this module is used.
335 llvm::SmallVector<LinkLibrary, 2> LinkLibraries;
336
337 /// Autolinking uses the framework name for linking purposes
338 /// when this is false and the export_as name otherwise.
339 bool UseExportAsModuleLinkName = false;
340
341 /// The set of "configuration macros", which are macros that
342 /// (intentionally) change how this module is built.
343 std::vector<std::string> ConfigMacros;
344
345 /// An unresolved conflict with another module.
346 struct UnresolvedConflict {
347 /// The (unresolved) module id.
348 ModuleId Id;
349
350 /// The message provided to the user when there is a conflict.
351 std::string Message;
352 };
353
354 /// The list of conflicts for which the module-id has not yet been
355 /// resolved.
356 std::vector<UnresolvedConflict> UnresolvedConflicts;
357
358 /// A conflict between two modules.
359 struct Conflict {
360 /// The module that this module conflicts with.
361 Module *Other;
362
363 /// The message provided to the user when there is a conflict.
364 std::string Message;
365 };
366
367 /// The list of conflicts.
368 std::vector<Conflict> Conflicts;
369
370 /// Construct a new module or submodule.
371 Module(StringRef Name, SourceLocation DefinitionLoc, Module *Parent,
372 bool IsFramework, bool IsExplicit, unsigned VisibilityID);
373
374 ~Module();
375
376 /// Determine whether this module is available for use within the
377 /// current translation unit.
378 bool isAvailable() const { return IsAvailable; }
379
380 /// Determine whether this module is available for use within the
381 /// current translation unit.
382 ///
383 /// \param LangOpts The language options used for the current
384 /// translation unit.
385 ///
386 /// \param Target The target options used for the current translation unit.
387 ///
388 /// \param Req If this module is unavailable because of a missing requirement,
389 /// this parameter will be set to one of the requirements that is not met for
390 /// use of this module.
391 ///
392 /// \param MissingHeader If this module is unavailable because of a missing
393 /// header, this parameter will be set to one of the missing headers.
394 ///
395 /// \param ShadowingModule If this module is unavailable because it is
396 /// shadowed, this parameter will be set to the shadowing module.
397 bool isAvailable(const LangOptions &LangOpts,
398 const TargetInfo &Target,
399 Requirement &Req,
400 UnresolvedHeaderDirective &MissingHeader,
401 Module *&ShadowingModule) const;
402
403 /// Determine whether this module is a submodule.
404 bool isSubModule() const { return Parent != nullptr; }
405
406 /// Determine whether this module is a submodule of the given other
407 /// module.
408 bool isSubModuleOf(const Module *Other) const;
409
410 /// Determine whether this module is a part of a framework,
411 /// either because it is a framework module or because it is a submodule
412 /// of a framework module.
413 bool isPartOfFramework() const {
414 for (const Module *Mod = this; Mod; Mod = Mod->Parent)
415 if (Mod->IsFramework)
416 return true;
417
418 return false;
419 }
420
421 /// Determine whether this module is a subframework of another
422 /// framework.
423 bool isSubFramework() const {
424 return IsFramework && Parent && Parent->isPartOfFramework();
425 }
426
427 /// Set the parent of this module. This should only be used if the parent
428 /// could not be set during module creation.
429 void setParent(Module *M) {
430 assert(!Parent);
431 Parent = M;
432 Parent->SubModuleIndex[Name] = Parent->SubModules.size();
433 Parent->SubModules.push_back(this);
434 }
435
436 /// Retrieve the full name of this module, including the path from
437 /// its top-level module.
438 /// \param AllowStringLiterals If \c true, components that might not be
439 /// lexically valid as identifiers will be emitted as string literals.
440 std::string getFullModuleName(bool AllowStringLiterals = false) const;
441
442 /// Whether the full name of this module is equal to joining
443 /// \p nameParts with "."s.
444 ///
445 /// This is more efficient than getFullModuleName().
446 bool fullModuleNameIs(ArrayRef<StringRef> nameParts) const;
447
448 /// Retrieve the top-level module for this (sub)module, which may
449 /// be this module.
450 Module *getTopLevelModule() {
451 return const_cast<Module *>(
452 const_cast<const Module *>(this)->getTopLevelModule());
453 }
454
455 /// Retrieve the top-level module for this (sub)module, which may
456 /// be this module.
457 const Module *getTopLevelModule() const;
458
459 /// Retrieve the name of the top-level module.
460 StringRef getTopLevelModuleName() const {
461 return getTopLevelModule()->Name;
462 }
463
464 /// The serialized AST file for this module, if one was created.
465 const FileEntry *getASTFile() const {
466 return getTopLevelModule()->ASTFile;
467 }
468
469 /// Set the serialized AST file for the top-level module of this module.
470 void setASTFile(const FileEntry *File) {
471 assert((File == nullptr || getASTFile() == nullptr ||
472 getASTFile() == File) && "file path changed");
473 getTopLevelModule()->ASTFile = File;
474 }
475
476 /// Retrieve the directory for which this module serves as the
477 /// umbrella.
478 DirectoryName getUmbrellaDir() const;
479
480 /// Retrieve the header that serves as the umbrella header for this
481 /// module.
482 Header getUmbrellaHeader() const {
483 if (auto *E = Umbrella.dyn_cast<const FileEntry *>())
484 return Header{UmbrellaAsWritten, E};
485 return Header{};
486 }
487
488 /// Determine whether this module has an umbrella directory that is
489 /// not based on an umbrella header.
490 bool hasUmbrellaDir() const {
491 return Umbrella && Umbrella.is<const DirectoryEntry *>();
492 }
493
494 /// Add a top-level header associated with this module.
495 void addTopHeader(const FileEntry *File) {
496 assert(File);
497 TopHeaders.insert(File);
498 }
499
500 /// Add a top-level header filename associated with this module.
501 void addTopHeaderFilename(StringRef Filename) {
502 TopHeaderNames.push_back(Filename);
503 }
504
505 /// The top-level headers associated with this module.
506 ArrayRef<const FileEntry *> getTopHeaders(FileManager &FileMgr);
507
508 /// Determine whether this module has declared its intention to
509 /// directly use another module.
510 bool directlyUses(const Module *Requested) const;
511
512 /// Add the given feature requirement to the list of features
513 /// required by this module.
514 ///
515 /// \param Feature The feature that is required by this module (and
516 /// its submodules).
517 ///
518 /// \param RequiredState The required state of this feature: \c true
519 /// if it must be present, \c false if it must be absent.
520 ///
521 /// \param LangOpts The set of language options that will be used to
522 /// evaluate the availability of this feature.
523 ///
524 /// \param Target The target options that will be used to evaluate the
525 /// availability of this feature.
526 void addRequirement(StringRef Feature, bool RequiredState,
527 const LangOptions &LangOpts,
528 const TargetInfo &Target);
529
530 /// Mark this module and all of its submodules as unavailable.
531 void markUnavailable(bool MissingRequirement = false);
532
533 /// Find the submodule with the given name.
534 ///
535 /// \returns The submodule if found, or NULL otherwise.
536 Module *findSubmodule(StringRef Name) const;
537
538 /// Determine whether the specified module would be visible to
539 /// a lookup at the end of this module.
540 ///
541 /// FIXME: This may return incorrect results for (submodules of) the
542 /// module currently being built, if it's queried before we see all
543 /// of its imports.
544 bool isModuleVisible(const Module *M) const {
545 if (VisibleModulesCache.empty())
546 buildVisibleModulesCache();
547 return VisibleModulesCache.count(M);
548 }
549
550 unsigned getVisibilityID() const { return VisibilityID; }
551
552 using submodule_iterator = std::vector<Module *>::iterator;
553 using submodule_const_iterator = std::vector<Module *>::const_iterator;
554
555 submodule_iterator submodule_begin() { return SubModules.begin(); }
556 submodule_const_iterator submodule_begin() const {return SubModules.begin();}
557 submodule_iterator submodule_end() { return SubModules.end(); }
558 submodule_const_iterator submodule_end() const { return SubModules.end(); }
559
560 llvm::iterator_range<submodule_iterator> submodules() {
561 return llvm::make_range(submodule_begin(), submodule_end());
562 }
563 llvm::iterator_range<submodule_const_iterator> submodules() const {
564 return llvm::make_range(submodule_begin(), submodule_end());
565 }
566
567 /// Appends this module's list of exported modules to \p Exported.
568 ///
569 /// This provides a subset of immediately imported modules (the ones that are
570 /// directly exported), not the complete set of exported modules.
571 void getExportedModules(SmallVectorImpl<Module *> &Exported) const;
572
573 static StringRef getModuleInputBufferName() {
574 return "<module-includes>";
575 }
576
577 /// Print the module map for this module to the given stream.
578 void print(raw_ostream &OS, unsigned Indent = 0) const;
579
580 /// Dump the contents of this module to the given output stream.
581 void dump() const;
582
583private:
584 void buildVisibleModulesCache() const;
585};
586
587/// A set of visible modules.
588class VisibleModuleSet {
589public:
590 VisibleModuleSet() = default;
591 VisibleModuleSet(VisibleModuleSet &&O)
592 : ImportLocs(std::move(O.ImportLocs)), Generation(O.Generation ? 1 : 0) {
593 O.ImportLocs.clear();
594 ++O.Generation;
595 }
596
597 /// Move from another visible modules set. Guaranteed to leave the source
598 /// empty and bump the generation on both.
599 VisibleModuleSet &operator=(VisibleModuleSet &&O) {
600 ImportLocs = std::move(O.ImportLocs);
601 O.ImportLocs.clear();
602 ++O.Generation;
603 ++Generation;
604 return *this;
605 }
606
607 /// Get the current visibility generation. Incremented each time the
608 /// set of visible modules changes in any way.
609 unsigned getGeneration() const { return Generation; }
610
611 /// Determine whether a module is visible.
612 bool isVisible(const Module *M) const {
613 return getImportLoc(M).isValid();
614 }
615
616 /// Get the location at which the import of a module was triggered.
617 SourceLocation getImportLoc(const Module *M) const {
618 return M->getVisibilityID() < ImportLocs.size()
619 ? ImportLocs[M->getVisibilityID()]
620 : SourceLocation();
621 }
622
623 /// A callback to call when a module is made visible (directly or
624 /// indirectly) by a call to \ref setVisible.
625 using VisibleCallback = llvm::function_ref<void(Module *M)>;
626
627 /// A callback to call when a module conflict is found. \p Path
628 /// consists of a sequence of modules from the conflicting module to the one
629 /// made visible, where each was exported by the next.
630 using ConflictCallback =
631 llvm::function_ref<void(ArrayRef<Module *> Path, Module *Conflict,
632 StringRef Message)>;
633
634 /// Make a specific module visible.
635 void setVisible(Module *M, SourceLocation Loc,
636 VisibleCallback Vis = [](Module *) {},
637 ConflictCallback Cb = [](ArrayRef<Module *>, Module *,
638 StringRef) {});
639
640private:
641 /// Import locations for each visible module. Indexed by the module's
642 /// VisibilityID.
643 std::vector<SourceLocation> ImportLocs;
644
645 /// Visibility generation, bumped every time the visibility state changes.
646 unsigned Generation = 0;
647};
648
649} // namespace clang
650
651#endif // LLVM_CLANG_BASIC_MODULE_H
652