clang  10.0.0svn
SemaModule.cpp
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1 //===--- SemaModule.cpp - Semantic Analysis for Modules -------------------===//
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 // This file implements semantic analysis for modules (C++ modules syntax,
10 // Objective-C modules syntax, and Clang header modules).
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/AST/ASTConsumer.h"
15 #include "clang/Lex/HeaderSearch.h"
16 #include "clang/Lex/Preprocessor.h"
18 
19 using namespace clang;
20 using namespace sema;
21 
23  SourceLocation ImportLoc, DeclContext *DC,
24  bool FromInclude = false) {
25  SourceLocation ExternCLoc;
26 
27  if (auto *LSD = dyn_cast<LinkageSpecDecl>(DC)) {
28  switch (LSD->getLanguage()) {
30  if (ExternCLoc.isInvalid())
31  ExternCLoc = LSD->getBeginLoc();
32  break;
34  break;
35  }
36  DC = LSD->getParent();
37  }
38 
39  while (isa<LinkageSpecDecl>(DC) || isa<ExportDecl>(DC))
40  DC = DC->getParent();
41 
42  if (!isa<TranslationUnitDecl>(DC)) {
43  S.Diag(ImportLoc, (FromInclude && S.isModuleVisible(M))
44  ? diag::ext_module_import_not_at_top_level_noop
45  : diag::err_module_import_not_at_top_level_fatal)
46  << M->getFullModuleName() << DC;
47  S.Diag(cast<Decl>(DC)->getBeginLoc(),
48  diag::note_module_import_not_at_top_level)
49  << DC;
50  } else if (!M->IsExternC && ExternCLoc.isValid()) {
51  S.Diag(ImportLoc, diag::ext_module_import_in_extern_c)
52  << M->getFullModuleName();
53  S.Diag(ExternCLoc, diag::note_extern_c_begins_here);
54  }
55 }
56 
59  if (!ModuleScopes.empty() &&
60  ModuleScopes.back().Module->Kind == Module::GlobalModuleFragment) {
61  // Under -std=c++2a -fmodules-ts, we can find an explicit 'module;' after
62  // already implicitly entering the global module fragment. That's OK.
63  assert(getLangOpts().CPlusPlusModules && getLangOpts().ModulesTS &&
64  "unexpectedly encountered multiple global module fragment decls");
65  ModuleScopes.back().BeginLoc = ModuleLoc;
66  return nullptr;
67  }
68 
69  // We start in the global module; all those declarations are implicitly
70  // module-private (though they do not have module linkage).
71  auto &Map = PP.getHeaderSearchInfo().getModuleMap();
72  auto *GlobalModule = Map.createGlobalModuleFragmentForModuleUnit(ModuleLoc);
73  assert(GlobalModule && "module creation should not fail");
74 
75  // Enter the scope of the global module.
76  ModuleScopes.push_back({});
77  ModuleScopes.back().BeginLoc = ModuleLoc;
78  ModuleScopes.back().Module = GlobalModule;
79  VisibleModules.setVisible(GlobalModule, ModuleLoc);
80 
81  // All declarations created from now on are owned by the global module.
82  auto *TU = Context.getTranslationUnitDecl();
84  TU->setLocalOwningModule(GlobalModule);
85 
86  // FIXME: Consider creating an explicit representation of this declaration.
87  return nullptr;
88 }
89 
92  ModuleDeclKind MDK, ModuleIdPath Path, bool IsFirstDecl) {
93  assert((getLangOpts().ModulesTS || getLangOpts().CPlusPlusModules) &&
94  "should only have module decl in Modules TS or C++20");
95 
96  // A module implementation unit requires that we are not compiling a module
97  // of any kind. A module interface unit requires that we are not compiling a
98  // module map.
99  switch (getLangOpts().getCompilingModule()) {
101  // It's OK to compile a module interface as a normal translation unit.
102  break;
103 
105  if (MDK != ModuleDeclKind::Implementation)
106  break;
107 
108  // We were asked to compile a module interface unit but this is a module
109  // implementation unit. That indicates the 'export' is missing.
110  Diag(ModuleLoc, diag::err_module_interface_implementation_mismatch)
111  << FixItHint::CreateInsertion(ModuleLoc, "export ");
112  MDK = ModuleDeclKind::Interface;
113  break;
114 
116  Diag(ModuleLoc, diag::err_module_decl_in_module_map_module);
117  return nullptr;
118 
120  Diag(ModuleLoc, diag::err_module_decl_in_header_module);
121  return nullptr;
122  }
123 
124  assert(ModuleScopes.size() <= 1 && "expected to be at global module scope");
125 
126  // FIXME: Most of this work should be done by the preprocessor rather than
127  // here, in order to support macro import.
128 
129  // Only one module-declaration is permitted per source file.
130  if (!ModuleScopes.empty() &&
131  ModuleScopes.back().Module->isModulePurview()) {
132  Diag(ModuleLoc, diag::err_module_redeclaration);
133  Diag(VisibleModules.getImportLoc(ModuleScopes.back().Module),
134  diag::note_prev_module_declaration);
135  return nullptr;
136  }
137 
138  // Find the global module fragment we're adopting into this module, if any.
139  Module *GlobalModuleFragment = nullptr;
140  if (!ModuleScopes.empty() &&
141  ModuleScopes.back().Module->Kind == Module::GlobalModuleFragment)
142  GlobalModuleFragment = ModuleScopes.back().Module;
143 
144  // In C++20, the module-declaration must be the first declaration if there
145  // is no global module fragment.
146  if (getLangOpts().CPlusPlusModules && !IsFirstDecl && !GlobalModuleFragment) {
147  Diag(ModuleLoc, diag::err_module_decl_not_at_start);
148  SourceLocation BeginLoc =
149  ModuleScopes.empty()
150  ? SourceMgr.getLocForStartOfFile(SourceMgr.getMainFileID())
151  : ModuleScopes.back().BeginLoc;
152  if (BeginLoc.isValid()) {
153  Diag(BeginLoc, diag::note_global_module_introducer_missing)
154  << FixItHint::CreateInsertion(BeginLoc, "module;\n");
155  }
156  }
157 
158  // Flatten the dots in a module name. Unlike Clang's hierarchical module map
159  // modules, the dots here are just another character that can appear in a
160  // module name.
161  std::string ModuleName;
162  for (auto &Piece : Path) {
163  if (!ModuleName.empty())
164  ModuleName += ".";
165  ModuleName += Piece.first->getName();
166  }
167 
168  // If a module name was explicitly specified on the command line, it must be
169  // correct.
170  if (!getLangOpts().CurrentModule.empty() &&
171  getLangOpts().CurrentModule != ModuleName) {
172  Diag(Path.front().second, diag::err_current_module_name_mismatch)
173  << SourceRange(Path.front().second, Path.back().second)
174  << getLangOpts().CurrentModule;
175  return nullptr;
176  }
177  const_cast<LangOptions&>(getLangOpts()).CurrentModule = ModuleName;
178 
179  auto &Map = PP.getHeaderSearchInfo().getModuleMap();
180  Module *Mod;
181 
182  switch (MDK) {
183  case ModuleDeclKind::Interface: {
184  // We can't have parsed or imported a definition of this module or parsed a
185  // module map defining it already.
186  if (auto *M = Map.findModule(ModuleName)) {
187  Diag(Path[0].second, diag::err_module_redefinition) << ModuleName;
188  if (M->DefinitionLoc.isValid())
189  Diag(M->DefinitionLoc, diag::note_prev_module_definition);
190  else if (const auto *FE = M->getASTFile())
191  Diag(M->DefinitionLoc, diag::note_prev_module_definition_from_ast_file)
192  << FE->getName();
193  Mod = M;
194  break;
195  }
196 
197  // Create a Module for the module that we're defining.
198  Mod = Map.createModuleForInterfaceUnit(ModuleLoc, ModuleName,
199  GlobalModuleFragment);
200  assert(Mod && "module creation should not fail");
201  break;
202  }
203 
204  case ModuleDeclKind::Implementation:
205  std::pair<IdentifierInfo *, SourceLocation> ModuleNameLoc(
206  PP.getIdentifierInfo(ModuleName), Path[0].second);
207  Mod = getModuleLoader().loadModule(ModuleLoc, {ModuleNameLoc},
209  /*IsInclusionDirective=*/false);
210  if (!Mod) {
211  Diag(ModuleLoc, diag::err_module_not_defined) << ModuleName;
212  // Create an empty module interface unit for error recovery.
213  Mod = Map.createModuleForInterfaceUnit(ModuleLoc, ModuleName,
214  GlobalModuleFragment);
215  }
216  break;
217  }
218 
219  if (!GlobalModuleFragment) {
220  ModuleScopes.push_back({});
221  if (getLangOpts().ModulesLocalVisibility)
222  ModuleScopes.back().OuterVisibleModules = std::move(VisibleModules);
223  } else {
224  // We're done with the global module fragment now.
225  ActOnEndOfTranslationUnitFragment(TUFragmentKind::Global);
226  }
227 
228  // Switch from the global module fragment (if any) to the named module.
229  ModuleScopes.back().BeginLoc = StartLoc;
230  ModuleScopes.back().Module = Mod;
231  ModuleScopes.back().ModuleInterface = MDK != ModuleDeclKind::Implementation;
232  VisibleModules.setVisible(Mod, ModuleLoc);
233 
234  // From now on, we have an owning module for all declarations we see.
235  // However, those declarations are module-private unless explicitly
236  // exported.
237  auto *TU = Context.getTranslationUnitDecl();
239  TU->setLocalOwningModule(Mod);
240 
241  // FIXME: Create a ModuleDecl.
242  return nullptr;
243 }
244 
247  SourceLocation PrivateLoc) {
248  // C++20 [basic.link]/2:
249  // A private-module-fragment shall appear only in a primary module
250  // interface unit.
251  switch (ModuleScopes.empty() ? Module::GlobalModuleFragment
252  : ModuleScopes.back().Module->Kind) {
255  Diag(PrivateLoc, diag::err_private_module_fragment_not_module);
256  return nullptr;
257 
259  Diag(PrivateLoc, diag::err_private_module_fragment_redefined);
260  Diag(ModuleScopes.back().BeginLoc, diag::note_previous_definition);
261  return nullptr;
262 
264  break;
265  }
266 
267  if (!ModuleScopes.back().ModuleInterface) {
268  Diag(PrivateLoc, diag::err_private_module_fragment_not_module_interface);
269  Diag(ModuleScopes.back().BeginLoc,
270  diag::note_not_module_interface_add_export)
271  << FixItHint::CreateInsertion(ModuleScopes.back().BeginLoc, "export ");
272  return nullptr;
273  }
274 
275  // FIXME: Check this isn't a module interface partition.
276  // FIXME: Check that this translation unit does not import any partitions;
277  // such imports would violate [basic.link]/2's "shall be the only module unit"
278  // restriction.
279 
280  // We've finished the public fragment of the translation unit.
281  ActOnEndOfTranslationUnitFragment(TUFragmentKind::Normal);
282 
283  auto &Map = PP.getHeaderSearchInfo().getModuleMap();
284  Module *PrivateModuleFragment =
285  Map.createPrivateModuleFragmentForInterfaceUnit(
286  ModuleScopes.back().Module, PrivateLoc);
287  assert(PrivateModuleFragment && "module creation should not fail");
288 
289  // Enter the scope of the private module fragment.
290  ModuleScopes.push_back({});
291  ModuleScopes.back().BeginLoc = ModuleLoc;
292  ModuleScopes.back().Module = PrivateModuleFragment;
293  ModuleScopes.back().ModuleInterface = true;
294  VisibleModules.setVisible(PrivateModuleFragment, ModuleLoc);
295 
296  // All declarations created from now on are scoped to the private module
297  // fragment (and are neither visible nor reachable in importers of the module
298  // interface).
299  auto *TU = Context.getTranslationUnitDecl();
301  TU->setLocalOwningModule(PrivateModuleFragment);
302 
303  // FIXME: Consider creating an explicit representation of this declaration.
304  return nullptr;
305 }
306 
308  SourceLocation ExportLoc,
309  SourceLocation ImportLoc,
310  ModuleIdPath Path) {
311  // Flatten the module path for a Modules TS module name.
312  std::pair<IdentifierInfo *, SourceLocation> ModuleNameLoc;
313  if (getLangOpts().ModulesTS) {
314  std::string ModuleName;
315  for (auto &Piece : Path) {
316  if (!ModuleName.empty())
317  ModuleName += ".";
318  ModuleName += Piece.first->getName();
319  }
320  ModuleNameLoc = {PP.getIdentifierInfo(ModuleName), Path[0].second};
321  Path = ModuleIdPath(ModuleNameLoc);
322  }
323 
324  Module *Mod =
325  getModuleLoader().loadModule(ImportLoc, Path, Module::AllVisible,
326  /*IsInclusionDirective=*/false);
327  if (!Mod)
328  return true;
329 
330  return ActOnModuleImport(StartLoc, ExportLoc, ImportLoc, Mod, Path);
331 }
332 
333 /// Determine whether \p D is lexically within an export-declaration.
334 static const ExportDecl *getEnclosingExportDecl(const Decl *D) {
335  for (auto *DC = D->getLexicalDeclContext(); DC; DC = DC->getLexicalParent())
336  if (auto *ED = dyn_cast<ExportDecl>(DC))
337  return ED;
338  return nullptr;
339 }
340 
342  SourceLocation ExportLoc,
343  SourceLocation ImportLoc,
344  Module *Mod, ModuleIdPath Path) {
345  VisibleModules.setVisible(Mod, ImportLoc);
346 
347  checkModuleImportContext(*this, Mod, ImportLoc, CurContext);
348 
349  // FIXME: we should support importing a submodule within a different submodule
350  // of the same top-level module. Until we do, make it an error rather than
351  // silently ignoring the import.
352  // Import-from-implementation is valid in the Modules TS. FIXME: Should we
353  // warn on a redundant import of the current module?
354  // FIXME: Import of a module from an implementation partition of the same
355  // module is permitted.
356  if (Mod->getTopLevelModuleName() == getLangOpts().CurrentModule &&
357  (getLangOpts().isCompilingModule() || !getLangOpts().ModulesTS)) {
358  Diag(ImportLoc, getLangOpts().isCompilingModule()
359  ? diag::err_module_self_import
360  : diag::err_module_import_in_implementation)
361  << Mod->getFullModuleName() << getLangOpts().CurrentModule;
362  }
363 
364  SmallVector<SourceLocation, 2> IdentifierLocs;
365  Module *ModCheck = Mod;
366  for (unsigned I = 0, N = Path.size(); I != N; ++I) {
367  // If we've run out of module parents, just drop the remaining identifiers.
368  // We need the length to be consistent.
369  if (!ModCheck)
370  break;
371  ModCheck = ModCheck->Parent;
372 
373  IdentifierLocs.push_back(Path[I].second);
374  }
375 
376  // If this was a header import, pad out with dummy locations.
377  // FIXME: Pass in and use the location of the header-name token in this case.
378  if (Path.empty()) {
379  for (; ModCheck; ModCheck = ModCheck->Parent) {
380  IdentifierLocs.push_back(SourceLocation());
381  }
382  }
383 
384  ImportDecl *Import = ImportDecl::Create(Context, CurContext, StartLoc,
385  Mod, IdentifierLocs);
386  CurContext->addDecl(Import);
387 
388  // Sequence initialization of the imported module before that of the current
389  // module, if any.
390  if (!ModuleScopes.empty())
391  Context.addModuleInitializer(ModuleScopes.back().Module, Import);
392 
393  // Re-export the module if needed.
394  if (!ModuleScopes.empty() && ModuleScopes.back().ModuleInterface) {
395  if (ExportLoc.isValid() || getEnclosingExportDecl(Import))
396  getCurrentModule()->Exports.emplace_back(Mod, false);
397  } else if (ExportLoc.isValid()) {
398  Diag(ExportLoc, diag::err_export_not_in_module_interface);
399  }
400 
401  return Import;
402 }
403 
405  checkModuleImportContext(*this, Mod, DirectiveLoc, CurContext, true);
406  BuildModuleInclude(DirectiveLoc, Mod);
407 }
408 
410  // Determine whether we're in the #include buffer for a module. The #includes
411  // in that buffer do not qualify as module imports; they're just an
412  // implementation detail of us building the module.
413  //
414  // FIXME: Should we even get ActOnModuleInclude calls for those?
415  bool IsInModuleIncludes =
416  TUKind == TU_Module &&
417  getSourceManager().isWrittenInMainFile(DirectiveLoc);
418 
419  bool ShouldAddImport = !IsInModuleIncludes;
420 
421  // If this module import was due to an inclusion directive, create an
422  // implicit import declaration to capture it in the AST.
423  if (ShouldAddImport) {
424  TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
425  ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
426  DirectiveLoc, Mod,
427  DirectiveLoc);
428  if (!ModuleScopes.empty())
429  Context.addModuleInitializer(ModuleScopes.back().Module, ImportD);
430  TU->addDecl(ImportD);
431  Consumer.HandleImplicitImportDecl(ImportD);
432  }
433 
434  getModuleLoader().makeModuleVisible(Mod, Module::AllVisible, DirectiveLoc);
435  VisibleModules.setVisible(Mod, DirectiveLoc);
436 }
437 
438 void Sema::ActOnModuleBegin(SourceLocation DirectiveLoc, Module *Mod) {
439  checkModuleImportContext(*this, Mod, DirectiveLoc, CurContext, true);
440 
441  ModuleScopes.push_back({});
442  ModuleScopes.back().Module = Mod;
443  if (getLangOpts().ModulesLocalVisibility)
444  ModuleScopes.back().OuterVisibleModules = std::move(VisibleModules);
445 
446  VisibleModules.setVisible(Mod, DirectiveLoc);
447 
448  // The enclosing context is now part of this module.
449  // FIXME: Consider creating a child DeclContext to hold the entities
450  // lexically within the module.
451  if (getLangOpts().trackLocalOwningModule()) {
452  for (auto *DC = CurContext; DC; DC = DC->getLexicalParent()) {
453  cast<Decl>(DC)->setModuleOwnershipKind(
454  getLangOpts().ModulesLocalVisibility
457  cast<Decl>(DC)->setLocalOwningModule(Mod);
458  }
459  }
460 }
461 
463  if (getLangOpts().ModulesLocalVisibility) {
464  VisibleModules = std::move(ModuleScopes.back().OuterVisibleModules);
465  // Leaving a module hides namespace names, so our visible namespace cache
466  // is now out of date.
467  VisibleNamespaceCache.clear();
468  }
469 
470  assert(!ModuleScopes.empty() && ModuleScopes.back().Module == Mod &&
471  "left the wrong module scope");
472  ModuleScopes.pop_back();
473 
474  // We got to the end of processing a local module. Create an
475  // ImportDecl as we would for an imported module.
476  FileID File = getSourceManager().getFileID(EomLoc);
477  SourceLocation DirectiveLoc;
478  if (EomLoc == getSourceManager().getLocForEndOfFile(File)) {
479  // We reached the end of a #included module header. Use the #include loc.
480  assert(File != getSourceManager().getMainFileID() &&
481  "end of submodule in main source file");
482  DirectiveLoc = getSourceManager().getIncludeLoc(File);
483  } else {
484  // We reached an EOM pragma. Use the pragma location.
485  DirectiveLoc = EomLoc;
486  }
487  BuildModuleInclude(DirectiveLoc, Mod);
488 
489  // Any further declarations are in whatever module we returned to.
490  if (getLangOpts().trackLocalOwningModule()) {
491  // The parser guarantees that this is the same context that we entered
492  // the module within.
493  for (auto *DC = CurContext; DC; DC = DC->getLexicalParent()) {
494  cast<Decl>(DC)->setLocalOwningModule(getCurrentModule());
495  if (!getCurrentModule())
496  cast<Decl>(DC)->setModuleOwnershipKind(
498  }
499  }
500 }
501 
503  Module *Mod) {
504  // Bail if we're not allowed to implicitly import a module here.
505  if (isSFINAEContext() || !getLangOpts().ModulesErrorRecovery ||
506  VisibleModules.isVisible(Mod))
507  return;
508 
509  // Create the implicit import declaration.
510  TranslationUnitDecl *TU = getASTContext().getTranslationUnitDecl();
511  ImportDecl *ImportD = ImportDecl::CreateImplicit(getASTContext(), TU,
512  Loc, Mod, Loc);
513  TU->addDecl(ImportD);
514  Consumer.HandleImplicitImportDecl(ImportD);
515 
516  // Make the module visible.
517  getModuleLoader().makeModuleVisible(Mod, Module::AllVisible, Loc);
518  VisibleModules.setVisible(Mod, Loc);
519 }
520 
521 /// We have parsed the start of an export declaration, including the '{'
522 /// (if present).
524  SourceLocation LBraceLoc) {
525  ExportDecl *D = ExportDecl::Create(Context, CurContext, ExportLoc);
526 
527  // Set this temporarily so we know the export-declaration was braced.
528  D->setRBraceLoc(LBraceLoc);
529 
530  // C++2a [module.interface]p1:
531  // An export-declaration shall appear only [...] in the purview of a module
532  // interface unit. An export-declaration shall not appear directly or
533  // indirectly within [...] a private-module-fragment.
534  if (ModuleScopes.empty() || !ModuleScopes.back().Module->isModulePurview()) {
535  Diag(ExportLoc, diag::err_export_not_in_module_interface) << 0;
536  } else if (!ModuleScopes.back().ModuleInterface) {
537  Diag(ExportLoc, diag::err_export_not_in_module_interface) << 1;
538  Diag(ModuleScopes.back().BeginLoc,
539  diag::note_not_module_interface_add_export)
540  << FixItHint::CreateInsertion(ModuleScopes.back().BeginLoc, "export ");
541  } else if (ModuleScopes.back().Module->Kind ==
543  Diag(ExportLoc, diag::err_export_in_private_module_fragment);
544  Diag(ModuleScopes.back().BeginLoc, diag::note_private_module_fragment);
545  }
546 
547  for (const DeclContext *DC = CurContext; DC; DC = DC->getLexicalParent()) {
548  if (const auto *ND = dyn_cast<NamespaceDecl>(DC)) {
549  // An export-declaration shall not appear directly or indirectly within
550  // an unnamed namespace [...]
551  if (ND->isAnonymousNamespace()) {
552  Diag(ExportLoc, diag::err_export_within_anonymous_namespace);
553  Diag(ND->getLocation(), diag::note_anonymous_namespace);
554  // Don't diagnose internal-linkage declarations in this region.
555  D->setInvalidDecl();
556  break;
557  }
558 
559  // A declaration is exported if it is [...] a namespace-definition
560  // that contains an exported declaration.
561  //
562  // Defer exporting the namespace until after we leave it, in order to
563  // avoid marking all subsequent declarations in the namespace as exported.
564  if (!DeferredExportedNamespaces.insert(ND).second)
565  break;
566  }
567  }
568 
569  // [...] its declaration or declaration-seq shall not contain an
570  // export-declaration.
571  if (auto *ED = getEnclosingExportDecl(D)) {
572  Diag(ExportLoc, diag::err_export_within_export);
573  if (ED->hasBraces())
574  Diag(ED->getLocation(), diag::note_export);
575  }
576 
577  CurContext->addDecl(D);
578  PushDeclContext(S, D);
580  return D;
581 }
582 
583 static bool checkExportedDeclContext(Sema &S, DeclContext *DC,
584  SourceLocation BlockStart);
585 
586 namespace {
587 enum class UnnamedDeclKind {
588  Empty,
589  StaticAssert,
590  Asm,
591  UsingDirective,
592  Context
593 };
594 }
595 
597  if (isa<EmptyDecl>(D))
598  return UnnamedDeclKind::Empty;
599  if (isa<StaticAssertDecl>(D))
600  return UnnamedDeclKind::StaticAssert;
601  if (isa<FileScopeAsmDecl>(D))
602  return UnnamedDeclKind::Asm;
603  if (isa<UsingDirectiveDecl>(D))
604  return UnnamedDeclKind::UsingDirective;
605  // Everything else either introduces one or more names or is ill-formed.
606  return llvm::None;
607 }
608 
609 unsigned getUnnamedDeclDiag(UnnamedDeclKind UDK, bool InBlock) {
610  switch (UDK) {
611  case UnnamedDeclKind::Empty:
612  case UnnamedDeclKind::StaticAssert:
613  // Allow empty-declarations and static_asserts in an export block as an
614  // extension.
615  return InBlock ? diag::ext_export_no_name_block : diag::err_export_no_name;
616 
617  case UnnamedDeclKind::UsingDirective:
618  // Allow exporting using-directives as an extension.
619  return diag::ext_export_using_directive;
620 
621  case UnnamedDeclKind::Context:
622  // Allow exporting DeclContexts that transitively contain no declarations
623  // as an extension.
624  return diag::ext_export_no_names;
625 
627  return diag::err_export_no_name;
628  }
629  llvm_unreachable("unknown kind");
630 }
631 
633  SourceLocation BlockStart) {
634  S.Diag(D->getLocation(), getUnnamedDeclDiag(UDK, BlockStart.isValid()))
635  << (unsigned)UDK;
636  if (BlockStart.isValid())
637  S.Diag(BlockStart, diag::note_export);
638 }
639 
640 /// Check that it's valid to export \p D.
641 static bool checkExportedDecl(Sema &S, Decl *D, SourceLocation BlockStart) {
642  // C++2a [module.interface]p3:
643  // An exported declaration shall declare at least one name
644  if (auto UDK = getUnnamedDeclKind(D))
645  diagExportedUnnamedDecl(S, *UDK, D, BlockStart);
646 
647  // [...] shall not declare a name with internal linkage.
648  if (auto *ND = dyn_cast<NamedDecl>(D)) {
649  // Don't diagnose anonymous union objects; we'll diagnose their members
650  // instead.
651  if (ND->getDeclName() && ND->getFormalLinkage() == InternalLinkage) {
652  S.Diag(ND->getLocation(), diag::err_export_internal) << ND;
653  if (BlockStart.isValid())
654  S.Diag(BlockStart, diag::note_export);
655  }
656  }
657 
658  // C++2a [module.interface]p5:
659  // all entities to which all of the using-declarators ultimately refer
660  // shall have been introduced with a name having external linkage
661  if (auto *USD = dyn_cast<UsingShadowDecl>(D)) {
662  NamedDecl *Target = USD->getUnderlyingDecl();
663  if (Target->getFormalLinkage() == InternalLinkage) {
664  S.Diag(USD->getLocation(), diag::err_export_using_internal) << Target;
665  S.Diag(Target->getLocation(), diag::note_using_decl_target);
666  if (BlockStart.isValid())
667  S.Diag(BlockStart, diag::note_export);
668  }
669  }
670 
671  // Recurse into namespace-scope DeclContexts. (Only namespace-scope
672  // declarations are exported.)
673  if (auto *DC = dyn_cast<DeclContext>(D))
674  if (DC->getRedeclContext()->isFileContext() && !isa<EnumDecl>(D))
675  return checkExportedDeclContext(S, DC, BlockStart);
676  return false;
677 }
678 
679 /// Check that it's valid to export all the declarations in \p DC.
681  SourceLocation BlockStart) {
682  bool AllUnnamed = true;
683  for (auto *D : DC->decls())
684  AllUnnamed &= checkExportedDecl(S, D, BlockStart);
685  return AllUnnamed;
686 }
687 
688 /// Complete the definition of an export declaration.
690  auto *ED = cast<ExportDecl>(D);
691  if (RBraceLoc.isValid())
692  ED->setRBraceLoc(RBraceLoc);
693 
694  PopDeclContext();
695 
696  if (!D->isInvalidDecl()) {
697  SourceLocation BlockStart =
698  ED->hasBraces() ? ED->getBeginLoc() : SourceLocation();
699  for (auto *Child : ED->decls()) {
700  if (checkExportedDecl(*this, Child, BlockStart)) {
701  // If a top-level child is a linkage-spec declaration, it might contain
702  // no declarations (transitively), in which case it's ill-formed.
703  diagExportedUnnamedDecl(*this, UnnamedDeclKind::Context, Child,
704  BlockStart);
705  }
706  }
707  }
708 
709  return D;
710 }
static DiagnosticBuilder Diag(DiagnosticsEngine *Diags, const LangOptions &Features, FullSourceLoc TokLoc, const char *TokBegin, const char *TokRangeBegin, const char *TokRangeEnd, unsigned DiagID)
Produce a diagnostic highlighting some portion of a literal.
DeclResult ActOnModuleImport(SourceLocation StartLoc, SourceLocation ExportLoc, SourceLocation ImportLoc, ModuleIdPath Path)
The parser has processed a module import declaration.
Definition: SemaModule.cpp:307
DeclGroupPtrTy ActOnPrivateModuleFragmentDecl(SourceLocation ModuleLoc, SourceLocation PrivateLoc)
The parser has processed a private-module-fragment declaration that begins the definition of the priv...
Definition: SemaModule.cpp:246
This declaration has an owning module, but is only visible to lookups that occur within that module...
static llvm::Optional< UnnamedDeclKind > getUnnamedDeclKind(Decl *D)
Definition: SemaModule.cpp:596
unsigned IsExternC
Whether this is an &#39;extern "C"&#39; module (which implicitly puts all headers in it within an &#39;extern "C"...
Definition: Module.h:237
SemaDiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID)
Emit a diagnostic.
Definition: Sema.h:1380
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:88
bool isModuleVisible(const Module *M, bool ModulePrivate=false)
Wrapper for void* pointer.
Definition: Ownership.h:50
This is a module that was defined by a module map and built out of header files.
Definition: Module.h:75
static void checkModuleImportContext(Sema &S, Module *M, SourceLocation ImportLoc, DeclContext *DC, bool FromInclude=false)
Definition: SemaModule.cpp:22
Compiling a C++ modules TS module interface unit.
Definition: LangOptions.h:84
decl_range decls() const
decls_begin/decls_end - Iterate over the declarations stored in this context.
Definition: DeclBase.h:2028
bool isInvalidDecl() const
Definition: DeclBase.h:553
This is the private module fragment within some C++ module.
Definition: Module.h:84
Linkage getFormalLinkage() const
Get the linkage from a semantic point of view.
Definition: Decl.h:370
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:49
ArrayRef< std::pair< IdentifierInfo *, SourceLocation > > ModuleIdPath
A sequence of identifier/location pairs used to describe a particular module or submodule, e.g., std.vector.
Definition: ModuleLoader.h:32
Compiling a module from a module map.
Definition: LangOptions.h:78
Describes a module or submodule.
Definition: Module.h:64
StringRef getTopLevelModuleName() const
Retrieve the name of the top-level module.
Definition: Module.h:467
std::string getFullModuleName(bool AllowStringLiterals=false) const
Retrieve the full name of this module, including the path from its top-level module.
Definition: Module.cpp:213
Module * Parent
The parent of this module.
Definition: Module.h:92
void ActOnModuleInclude(SourceLocation DirectiveLoc, Module *Mod)
The parser has processed a module import translated from a #include or similar preprocessing directiv...
Definition: SemaModule.cpp:404
Scope - A scope is a transient data structure that is used while parsing the program.
Definition: Scope.h:40
DeclContext * getLexicalDeclContext()
getLexicalDeclContext - The declaration context where this Decl was lexically declared (LexicalDC)...
Definition: DeclBase.h:828
static bool checkExportedDecl(Sema &S, Decl *D, SourceLocation BlockStart)
Check that it&#39;s valid to export D.
Definition: SemaModule.cpp:641
static ImportDecl * Create(ASTContext &C, DeclContext *DC, SourceLocation StartLoc, Module *Imported, ArrayRef< SourceLocation > IdentifierLocs)
Create a new module import declaration.
Definition: Decl.cpp:4827
Sema - This implements semantic analysis and AST building for C.
Definition: Sema.h:328
DeclContext * getLexicalParent()
getLexicalParent - Returns the containing lexical DeclContext.
Definition: DeclBase.h:1795
ModuleDeclKind
Definition: Sema.h:2277
Compiling a module from a list of header files.
Definition: LangOptions.h:81
void setInvalidDecl(bool Invalid=true)
setInvalidDecl - Indicates the Decl had a semantic error.
Definition: DeclBase.cpp:132
Defines the clang::Preprocessor interface.
Not compiling a module interface at all.
Definition: LangOptions.h:75
bool isFileContext() const
Definition: DeclBase.h:1849
UnnamedDeclKind
Definition: SemaModule.cpp:587
Decl * ActOnFinishExportDecl(Scope *S, Decl *ExportDecl, SourceLocation RBraceLoc)
Complete the definition of an export declaration.
Definition: SemaModule.cpp:689
Module(StringRef Name, SourceLocation DefinitionLoc, Module *Parent, bool IsFramework, bool IsExplicit, unsigned VisibilityID)
Construct a new module or submodule.
Definition: Module.cpp:37
This declaration has an owning module, and is visible when that module is imported.
DeclContext * getParent()
getParent - Returns the containing DeclContext.
Definition: DeclBase.h:1779
void BuildModuleInclude(SourceLocation DirectiveLoc, Module *Mod)
Definition: SemaModule.cpp:409
Represents a C++ Modules TS module export declaration.
Definition: Decl.h:4286
This declaration has an owning module, but is globally visible (typically because its owning module i...
ActionResult - This structure is used while parsing/acting on expressions, stmts, etc...
Definition: Ownership.h:153
Encodes a location in the source.
static ExportDecl * Create(ASTContext &C, DeclContext *DC, SourceLocation ExportLoc)
Definition: Decl.cpp:4873
void setModuleOwnershipKind(ModuleOwnershipKind MOK)
Set whether this declaration is hidden from name lookup.
Definition: DeclBase.h:791
static bool checkExportedDeclContext(Sema &S, DeclContext *DC, SourceLocation BlockStart)
Check that it&#39;s valid to export all the declarations in DC.
Definition: SemaModule.cpp:680
DeclGroupPtrTy ActOnGlobalModuleFragmentDecl(SourceLocation ModuleLoc)
The parser has processed a global-module-fragment declaration that begins the definition of the globa...
Definition: SemaModule.cpp:58
This is a fragment of the global module within some C++ module.
Definition: Module.h:81
Decl * ActOnStartExportDecl(Scope *S, SourceLocation ExportLoc, SourceLocation LBraceLoc)
We have parsed the start of an export declaration, including the &#39;{&#39; (if present).
Definition: SemaModule.cpp:523
static ImportDecl * CreateImplicit(ASTContext &C, DeclContext *DC, SourceLocation StartLoc, Module *Imported, SourceLocation EndLoc)
Create a new module import declaration for an implicitly-generated import.
Definition: Decl.cpp:4835
Describes a module import declaration, which makes the contents of the named module visible in the cu...
Definition: Decl.h:4221
void createImplicitModuleImportForErrorRecovery(SourceLocation Loc, Module *Mod)
Create an implicit import of the given module at the given source location, for error recovery...
Definition: SemaModule.cpp:502
An opaque identifier used by SourceManager which refers to a source file (MemoryBuffer) along with it...
Dataflow Directional Tag Classes.
bool isValid() const
Return true if this is a valid SourceLocation object.
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1271
void ActOnModuleBegin(SourceLocation DirectiveLoc, Module *Mod)
The parsed has entered a submodule.
Definition: SemaModule.cpp:438
unsigned getUnnamedDeclDiag(UnnamedDeclKind UDK, bool InBlock)
Definition: SemaModule.cpp:609
This declaration is not owned by a module.
All of the names in this module are visible.
Definition: Module.h:277
Assembly: we accept this only so that we can preprocess it.
static const ExportDecl * getEnclosingExportDecl(const Decl *D)
Determine whether D is lexically within an export-declaration.
Definition: SemaModule.cpp:334
DeclContext * getRedeclContext()
getRedeclContext - Retrieve the context in which an entity conflicts with other entities of the same ...
Definition: DeclBase.cpp:1744
DeclGroupPtrTy ActOnModuleDecl(SourceLocation StartLoc, SourceLocation ModuleLoc, ModuleDeclKind MDK, ModuleIdPath Path, bool IsFirstDecl)
The parser has processed a module-declaration that begins the definition of a module interface or imp...
Definition: SemaModule.cpp:91
Internal linkage, which indicates that the entity can be referred to from within the translation unit...
Definition: Linkage.h:31
static FixItHint CreateInsertion(SourceLocation InsertionLoc, StringRef Code, bool BeforePreviousInsertions=false)
Create a code modification hint that inserts the given code string at a specific location.
Definition: Diagnostic.h:92
void addDecl(Decl *D)
Add the declaration D into this context.
Definition: DeclBase.cpp:1521
static void diagExportedUnnamedDecl(Sema &S, UnnamedDeclKind UDK, Decl *D, SourceLocation BlockStart)
Definition: SemaModule.cpp:632
void setRBraceLoc(SourceLocation L)
Definition: Decl.h:4306
TranslationUnitDecl * getTranslationUnitDecl() const
Definition: ASTContext.h:1005
void addModuleInitializer(Module *M, Decl *Init)
Add a declaration to the list of declarations that are initialized for a module.
The top declaration context.
Definition: Decl.h:107
void ActOnModuleEnd(SourceLocation DirectiveLoc, Module *Mod)
The parser has left a submodule.
Definition: SemaModule.cpp:462
A trivial tuple used to represent a source range.
This represents a decl that may have a name.
Definition: Decl.h:248
TranslationUnitDecl * getTranslationUnitDecl()
Definition: DeclBase.cpp:362
SourceLocation getLocation() const
Definition: DeclBase.h:429
This is a C++ Modules TS module interface unit.
Definition: Module.h:78
The translation unit is a module.
Definition: LangOptions.h:387