1 //===- IndexDecl.cpp - Indexing declarations ------------------------------===//
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 #include "IndexingContext.h"
10 #include "clang/Index/IndexDataConsumer.h"
11 #include "clang/AST/DeclVisitor.h"
12 
13 using namespace clang;
14 using namespace index;
15 
16 #define TRY_DECL(D,CALL_EXPR)                                                  \
17   do {                                                                         \
18     if (!IndexCtx.shouldIndex(D)) return true;                                 \
19     if (!CALL_EXPR)                                                            \
20       return false;                                                            \
21   } while (0)
22 
23 #define TRY_TO(CALL_EXPR)                                                      \
24   do {                                                                         \
25     if (!CALL_EXPR)                                                            \
26       return false;                                                            \
27   } while (0)
28 
29 namespace {
30 
31 class IndexingDeclVisitor : public ConstDeclVisitor<IndexingDeclVisitor, bool> {
32   IndexingContext &IndexCtx;
33 
34 public:
35   explicit IndexingDeclVisitor(IndexingContext &indexCtx)
36     : IndexCtx(indexCtx) { }
37 
38   bool Handled = true;
39 
40   bool VisitDecl(const Decl *D) {
41     Handled = false;
42     return true;
43   }
44 
45   /// Returns true if the given method has been defined explicitly by the
46   /// user.
47   static bool hasUserDefined(const ObjCMethodDecl *D,
48                              const ObjCImplDecl *Container) {
49     const ObjCMethodDecl *MD = Container->getMethod(D->getSelector(),
50                                                     D->isInstanceMethod());
51     return MD && !MD->isImplicit() && MD->isThisDeclarationADefinition();
52   }
53 
54   void handleTemplateArgumentLoc(const TemplateArgumentLoc &TALoc,
55                                  const NamedDecl *Parent,
56                                  const DeclContext *DC) {
57     const TemplateArgumentLocInfo &LocInfo = TALoc.getLocInfo();
58     switch (TALoc.getArgument().getKind()) {
59     case TemplateArgument::Expression:
60       IndexCtx.indexBody(LocInfo.getAsExpr(), Parent, DC);
61       break;
62     case TemplateArgument::Type:
63       IndexCtx.indexTypeSourceInfo(LocInfo.getAsTypeSourceInfo(), Parent, DC);
64       break;
65     case TemplateArgument::Template:
66     case TemplateArgument::TemplateExpansion:
67       IndexCtx.indexNestedNameSpecifierLoc(TALoc.getTemplateQualifierLoc(),
68                                            Parent, DC);
69       if (const TemplateDecl *TD = TALoc.getArgument()
70                                        .getAsTemplateOrTemplatePattern()
71                                        .getAsTemplateDecl()) {
72         if (const NamedDecl *TTD = TD->getTemplatedDecl())
73           IndexCtx.handleReference(TTD, TALoc.getTemplateNameLoc(), Parent, DC);
74       }
75       break;
76     default:
77       break;
78     }
79   }
80 
81   void handleDeclarator(const DeclaratorDecl *D,
82                         const NamedDecl *Parent = nullptr,
83                         bool isIBType = false) {
84     if (!Parent) Parent = D;
85 
86     IndexCtx.indexTypeSourceInfo(D->getTypeSourceInfo(), Parent,
87                                  Parent->getLexicalDeclContext(),
88                                  /*isBase=*/false, isIBType);
89     IndexCtx.indexNestedNameSpecifierLoc(D->getQualifierLoc(), Parent);
90     if (IndexCtx.shouldIndexFunctionLocalSymbols()) {
91       if (const ParmVarDecl *Parm = dyn_cast<ParmVarDecl>(D)) {
92         auto *DC = Parm->getDeclContext();
93         if (auto *FD = dyn_cast<FunctionDecl>(DC)) {
94           if (IndexCtx.shouldIndexParametersInDeclarations() ||
95               FD->isThisDeclarationADefinition())
96             IndexCtx.handleDecl(Parm);
97         } else if (auto *MD = dyn_cast<ObjCMethodDecl>(DC)) {
98           if (MD->isThisDeclarationADefinition())
99             IndexCtx.handleDecl(Parm);
100         } else {
101           IndexCtx.handleDecl(Parm);
102         }
103       } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
104         if (IndexCtx.shouldIndexParametersInDeclarations() ||
105             FD->isThisDeclarationADefinition()) {
106           for (auto PI : FD->parameters()) {
107             IndexCtx.handleDecl(PI);
108           }
109         }
110       }
111     } else {
112       // Index the default parameter value for function definitions.
113       if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
114         if (FD->isThisDeclarationADefinition()) {
115           for (const auto *PV : FD->parameters()) {
116             if (PV->hasDefaultArg() && !PV->hasUninstantiatedDefaultArg() &&
117                 !PV->hasUnparsedDefaultArg())
118               IndexCtx.indexBody(PV->getDefaultArg(), D);
119           }
120         }
121       }
122     }
123   }
124 
125   bool handleObjCMethod(const ObjCMethodDecl *D,
126                         const ObjCPropertyDecl *AssociatedProp = nullptr) {
127     SmallVector<SymbolRelation, 4> Relations;
128     SmallVector<const ObjCMethodDecl*, 4> Overriden;
129 
130     D->getOverriddenMethods(Overriden);
131     for(auto overridden: Overriden) {
132       Relations.emplace_back((unsigned) SymbolRole::RelationOverrideOf,
133                              overridden);
134     }
135     if (AssociatedProp)
136       Relations.emplace_back((unsigned)SymbolRole::RelationAccessorOf,
137                              AssociatedProp);
138 
139     // getLocation() returns beginning token of a method declaration, but for
140     // indexing purposes we want to point to the base name.
141     SourceLocation MethodLoc = D->getSelectorStartLoc();
142     if (MethodLoc.isInvalid())
143       MethodLoc = D->getLocation();
144 
145     SourceLocation AttrLoc;
146 
147     // check for (getter=/setter=)
148     if (AssociatedProp) {
149       bool isGetter = !D->param_size();
150       AttrLoc = isGetter ?
151         AssociatedProp->getGetterNameLoc():
152         AssociatedProp->getSetterNameLoc();
153     }
154 
155     SymbolRoleSet Roles = (SymbolRoleSet)SymbolRole::Dynamic;
156     if (D->isImplicit()) {
157       if (AttrLoc.isValid()) {
158         MethodLoc = AttrLoc;
159       } else {
160         Roles |= (SymbolRoleSet)SymbolRole::Implicit;
161       }
162     } else if (AttrLoc.isValid()) {
163       IndexCtx.handleReference(D, AttrLoc, cast<NamedDecl>(D->getDeclContext()),
164                                D->getDeclContext(), 0);
165     }
166 
167     TRY_DECL(D, IndexCtx.handleDecl(D, MethodLoc, Roles, Relations));
168     IndexCtx.indexTypeSourceInfo(D->getReturnTypeSourceInfo(), D);
169     bool hasIBActionAndFirst = D->hasAttr<IBActionAttr>();
170     for (const auto *I : D->parameters()) {
171       handleDeclarator(I, D, /*isIBType=*/hasIBActionAndFirst);
172       hasIBActionAndFirst = false;
173     }
174 
175     if (D->isThisDeclarationADefinition()) {
176       const Stmt *Body = D->getBody();
177       if (Body) {
178         IndexCtx.indexBody(Body, D, D);
179       }
180     }
181     return true;
182   }
183 
184   /// Gather the declarations which the given declaration \D overrides in a
185   /// pseudo-override manner.
186   ///
187   /// Pseudo-overrides occur when a class template specialization declares
188   /// a declaration that has the same name as a similar declaration in the
189   /// non-specialized template.
190   void
191   gatherTemplatePseudoOverrides(const NamedDecl *D,
192                                 SmallVectorImpl<SymbolRelation> &Relations) {
193     if (!IndexCtx.getLangOpts().CPlusPlus)
194       return;
195     const auto *CTSD =
196         dyn_cast<ClassTemplateSpecializationDecl>(D->getLexicalDeclContext());
197     if (!CTSD)
198       return;
199     llvm::PointerUnion<ClassTemplateDecl *,
200                        ClassTemplatePartialSpecializationDecl *>
201         Template = CTSD->getSpecializedTemplateOrPartial();
202     if (const auto *CTD = Template.dyn_cast<ClassTemplateDecl *>()) {
203       const CXXRecordDecl *Pattern = CTD->getTemplatedDecl();
204       bool TypeOverride = isa<TypeDecl>(D);
205       for (const NamedDecl *ND : Pattern->lookup(D->getDeclName())) {
206         if (const auto *CTD = dyn_cast<ClassTemplateDecl>(ND))
207           ND = CTD->getTemplatedDecl();
208         if (ND->isImplicit())
209           continue;
210         // Types can override other types.
211         if (!TypeOverride) {
212           if (ND->getKind() != D->getKind())
213             continue;
214         } else if (!isa<TypeDecl>(ND))
215           continue;
216         if (const auto *FD = dyn_cast<FunctionDecl>(ND)) {
217           const auto *DFD = cast<FunctionDecl>(D);
218           // Function overrides are approximated using the number of parameters.
219           if (FD->getStorageClass() != DFD->getStorageClass() ||
220               FD->getNumParams() != DFD->getNumParams())
221             continue;
222         }
223         Relations.emplace_back(
224             SymbolRoleSet(SymbolRole::RelationSpecializationOf), ND);
225       }
226     }
227   }
228 
229   bool VisitFunctionDecl(const FunctionDecl *D) {
230     SymbolRoleSet Roles{};
231     SmallVector<SymbolRelation, 4> Relations;
232     if (auto *CXXMD = dyn_cast<CXXMethodDecl>(D)) {
233       if (CXXMD->isVirtual())
234         Roles |= (unsigned)SymbolRole::Dynamic;
235       for (const CXXMethodDecl *O : CXXMD->overridden_methods()) {
236         Relations.emplace_back((unsigned)SymbolRole::RelationOverrideOf, O);
237       }
238     }
239     gatherTemplatePseudoOverrides(D, Relations);
240     if (const auto *Base = D->getPrimaryTemplate())
241       Relations.push_back(
242           SymbolRelation(SymbolRoleSet(SymbolRole::RelationSpecializationOf),
243                          Base->getTemplatedDecl()));
244 
245     TRY_DECL(D, IndexCtx.handleDecl(D, Roles, Relations));
246     handleDeclarator(D);
247 
248     if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(D)) {
249       IndexCtx.handleReference(Ctor->getParent(), Ctor->getLocation(),
250                                Ctor->getParent(), Ctor->getDeclContext());
251 
252       // Constructor initializers.
253       for (const auto *Init : Ctor->inits()) {
254         if (Init->isWritten()) {
255           IndexCtx.indexTypeSourceInfo(Init->getTypeSourceInfo(), D);
256           if (const FieldDecl *Member = Init->getAnyMember())
257             IndexCtx.handleReference(Member, Init->getMemberLocation(), D, D,
258                                      (unsigned)SymbolRole::Write);
259           IndexCtx.indexBody(Init->getInit(), D, D);
260         }
261       }
262     } else if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(D)) {
263       if (auto TypeNameInfo = Dtor->getNameInfo().getNamedTypeInfo()) {
264         IndexCtx.handleReference(Dtor->getParent(),
265                                  TypeNameInfo->getTypeLoc().getBeginLoc(),
266                                  Dtor->getParent(), Dtor->getDeclContext());
267       }
268     } else if (const auto *Guide = dyn_cast<CXXDeductionGuideDecl>(D)) {
269       IndexCtx.handleReference(Guide->getDeducedTemplate()->getTemplatedDecl(),
270                                Guide->getLocation(), Guide,
271                                Guide->getDeclContext());
272     }
273     // Template specialization arguments.
274     if (const ASTTemplateArgumentListInfo *TemplateArgInfo =
275             D->getTemplateSpecializationArgsAsWritten()) {
276       for (const auto &Arg : TemplateArgInfo->arguments())
277         handleTemplateArgumentLoc(Arg, D, D->getLexicalDeclContext());
278     }
279 
280     if (D->isThisDeclarationADefinition()) {
281       const Stmt *Body = D->getBody();
282       if (Body) {
283         IndexCtx.indexBody(Body, D, D);
284       }
285     }
286     return true;
287   }
288 
289   bool VisitVarDecl(const VarDecl *D) {
290     SmallVector<SymbolRelation, 4> Relations;
291     gatherTemplatePseudoOverrides(D, Relations);
292     TRY_DECL(D, IndexCtx.handleDecl(D, SymbolRoleSet(), Relations));
293     handleDeclarator(D);
294     IndexCtx.indexBody(D->getInit(), D);
295     return true;
296   }
297 
298   bool VisitDecompositionDecl(const DecompositionDecl *D) {
299     for (const auto *Binding : D->bindings())
300       TRY_DECL(Binding, IndexCtx.handleDecl(Binding));
301     return Base::VisitDecompositionDecl(D);
302   }
303 
304   bool VisitFieldDecl(const FieldDecl *D) {
305     SmallVector<SymbolRelation, 4> Relations;
306     gatherTemplatePseudoOverrides(D, Relations);
307     TRY_DECL(D, IndexCtx.handleDecl(D, SymbolRoleSet(), Relations));
308     handleDeclarator(D);
309     if (D->isBitField())
310       IndexCtx.indexBody(D->getBitWidth(), D);
311     else if (D->hasInClassInitializer())
312       IndexCtx.indexBody(D->getInClassInitializer(), D);
313     return true;
314   }
315 
316   bool VisitObjCIvarDecl(const ObjCIvarDecl *D) {
317     if (D->getSynthesize()) {
318       // handled in VisitObjCPropertyImplDecl
319       return true;
320     }
321     TRY_DECL(D, IndexCtx.handleDecl(D));
322     handleDeclarator(D);
323     return true;
324   }
325 
326   bool VisitMSPropertyDecl(const MSPropertyDecl *D) {
327     TRY_DECL(D, IndexCtx.handleDecl(D));
328     handleDeclarator(D);
329     return true;
330   }
331 
332   bool VisitEnumConstantDecl(const EnumConstantDecl *D) {
333     TRY_DECL(D, IndexCtx.handleDecl(D));
334     IndexCtx.indexBody(D->getInitExpr(), D);
335     return true;
336   }
337 
338   bool VisitTypedefNameDecl(const TypedefNameDecl *D) {
339     if (!D->isTransparentTag()) {
340       SmallVector<SymbolRelation, 4> Relations;
341       gatherTemplatePseudoOverrides(D, Relations);
342       TRY_DECL(D, IndexCtx.handleDecl(D, SymbolRoleSet(), Relations));
343       IndexCtx.indexTypeSourceInfo(D->getTypeSourceInfo(), D);
344     }
345     return true;
346   }
347 
348   bool VisitTagDecl(const TagDecl *D) {
349     // Non-free standing tags are handled in indexTypeSourceInfo.
350     if (D->isFreeStanding()) {
351       if (D->isThisDeclarationADefinition()) {
352         SmallVector<SymbolRelation, 4> Relations;
353         gatherTemplatePseudoOverrides(D, Relations);
354         IndexCtx.indexTagDecl(D, Relations);
355       } else {
356         SmallVector<SymbolRelation, 1> Relations;
357         gatherTemplatePseudoOverrides(D, Relations);
358         return IndexCtx.handleDecl(D, D->getLocation(), SymbolRoleSet(),
359                                    Relations, D->getLexicalDeclContext());
360       }
361     }
362     return true;
363   }
364 
365   bool handleReferencedProtocols(const ObjCProtocolList &ProtList,
366                                  const ObjCContainerDecl *ContD,
367                                  SourceLocation SuperLoc) {
368     ObjCInterfaceDecl::protocol_loc_iterator LI = ProtList.loc_begin();
369     for (ObjCInterfaceDecl::protocol_iterator
370          I = ProtList.begin(), E = ProtList.end(); I != E; ++I, ++LI) {
371       SourceLocation Loc = *LI;
372       ObjCProtocolDecl *PD = *I;
373       SymbolRoleSet roles{};
374       if (Loc == SuperLoc)
375         roles |= (SymbolRoleSet)SymbolRole::Implicit;
376       TRY_TO(IndexCtx.handleReference(PD, Loc, ContD, ContD, roles,
377           SymbolRelation{(unsigned)SymbolRole::RelationBaseOf, ContD}));
378     }
379     return true;
380   }
381 
382   bool VisitObjCInterfaceDecl(const ObjCInterfaceDecl *D) {
383     if (D->isThisDeclarationADefinition()) {
384       TRY_DECL(D, IndexCtx.handleDecl(D));
385       SourceLocation SuperLoc = D->getSuperClassLoc();
386       if (auto *SuperD = D->getSuperClass()) {
387         bool hasSuperTypedef = false;
388         if (auto *TInfo = D->getSuperClassTInfo()) {
389           if (auto *TT = TInfo->getType()->getAs<TypedefType>()) {
390             if (auto *TD = TT->getDecl()) {
391               hasSuperTypedef = true;
392               TRY_TO(IndexCtx.handleReference(TD, SuperLoc, D, D,
393                                               SymbolRoleSet()));
394             }
395           }
396         }
397         SymbolRoleSet superRoles{};
398         if (hasSuperTypedef)
399           superRoles |= (SymbolRoleSet)SymbolRole::Implicit;
400         TRY_TO(IndexCtx.handleReference(SuperD, SuperLoc, D, D, superRoles,
401             SymbolRelation{(unsigned)SymbolRole::RelationBaseOf, D}));
402       }
403       TRY_TO(handleReferencedProtocols(D->getReferencedProtocols(), D,
404                                        SuperLoc));
405       TRY_TO(IndexCtx.indexDeclContext(D));
406     } else {
407       return IndexCtx.handleReference(D, D->getLocation(), nullptr,
408                                       D->getDeclContext(), SymbolRoleSet());
409     }
410     return true;
411   }
412 
413   bool VisitObjCProtocolDecl(const ObjCProtocolDecl *D) {
414     if (D->isThisDeclarationADefinition()) {
415       TRY_DECL(D, IndexCtx.handleDecl(D));
416       TRY_TO(handleReferencedProtocols(D->getReferencedProtocols(), D,
417                                        /*superLoc=*/SourceLocation()));
418       TRY_TO(IndexCtx.indexDeclContext(D));
419     } else {
420       return IndexCtx.handleReference(D, D->getLocation(), nullptr,
421                                       D->getDeclContext(), SymbolRoleSet());
422     }
423     return true;
424   }
425 
426   bool VisitObjCImplementationDecl(const ObjCImplementationDecl *D) {
427     const ObjCInterfaceDecl *Class = D->getClassInterface();
428     if (!Class)
429       return true;
430 
431     if (Class->isImplicitInterfaceDecl())
432       IndexCtx.handleDecl(Class);
433 
434     TRY_DECL(D, IndexCtx.handleDecl(D));
435 
436     // Visit implicit @synthesize property implementations first as their
437     // location is reported at the name of the @implementation block. This
438     // serves no purpose other than to simplify the FileCheck-based tests.
439     for (const auto *I : D->property_impls()) {
440       if (I->getLocation().isInvalid())
441         IndexCtx.indexDecl(I);
442     }
443     for (const auto *I : D->decls()) {
444       if (!isa<ObjCPropertyImplDecl>(I) ||
445           cast<ObjCPropertyImplDecl>(I)->getLocation().isValid())
446         IndexCtx.indexDecl(I);
447     }
448 
449     return true;
450   }
451 
452   bool VisitObjCCategoryDecl(const ObjCCategoryDecl *D) {
453     if (!IndexCtx.shouldIndex(D))
454       return true;
455     const ObjCInterfaceDecl *C = D->getClassInterface();
456     if (!C)
457       return true;
458     TRY_TO(IndexCtx.handleReference(C, D->getLocation(), D, D, SymbolRoleSet(),
459                                    SymbolRelation{
460                                      (unsigned)SymbolRole::RelationExtendedBy, D
461                                    }));
462     SourceLocation CategoryLoc = D->getCategoryNameLoc();
463     if (!CategoryLoc.isValid())
464       CategoryLoc = D->getLocation();
465     TRY_TO(IndexCtx.handleDecl(D, CategoryLoc));
466     TRY_TO(handleReferencedProtocols(D->getReferencedProtocols(), D,
467                                      /*superLoc=*/SourceLocation()));
468     TRY_TO(IndexCtx.indexDeclContext(D));
469     return true;
470   }
471 
472   bool VisitObjCCategoryImplDecl(const ObjCCategoryImplDecl *D) {
473     const ObjCCategoryDecl *Cat = D->getCategoryDecl();
474     if (!Cat)
475       return true;
476     const ObjCInterfaceDecl *C = D->getClassInterface();
477     if (C)
478       TRY_TO(IndexCtx.handleReference(C, D->getLocation(), D, D,
479                                       SymbolRoleSet()));
480     SourceLocation CategoryLoc = D->getCategoryNameLoc();
481     if (!CategoryLoc.isValid())
482       CategoryLoc = D->getLocation();
483     TRY_DECL(D, IndexCtx.handleDecl(D, CategoryLoc));
484     IndexCtx.indexDeclContext(D);
485     return true;
486   }
487 
488   bool VisitObjCMethodDecl(const ObjCMethodDecl *D) {
489     // Methods associated with a property, even user-declared ones, are
490     // handled when we handle the property.
491     if (D->isPropertyAccessor())
492       return true;
493 
494     handleObjCMethod(D);
495     return true;
496   }
497 
498   bool VisitObjCPropertyDecl(const ObjCPropertyDecl *D) {
499     if (ObjCMethodDecl *MD = D->getGetterMethodDecl())
500       if (MD->getLexicalDeclContext() == D->getLexicalDeclContext())
501         handleObjCMethod(MD, D);
502     if (ObjCMethodDecl *MD = D->getSetterMethodDecl())
503       if (MD->getLexicalDeclContext() == D->getLexicalDeclContext())
504         handleObjCMethod(MD, D);
505     TRY_DECL(D, IndexCtx.handleDecl(D));
506     if (IBOutletCollectionAttr *attr = D->getAttr<IBOutletCollectionAttr>())
507       IndexCtx.indexTypeSourceInfo(attr->getInterfaceLoc(), D,
508                                    D->getLexicalDeclContext(), false, true);
509     IndexCtx.indexTypeSourceInfo(D->getTypeSourceInfo(), D);
510     return true;
511   }
512 
513   bool VisitObjCPropertyImplDecl(const ObjCPropertyImplDecl *D) {
514     ObjCPropertyDecl *PD = D->getPropertyDecl();
515     auto *Container = cast<ObjCImplDecl>(D->getDeclContext());
516     SourceLocation Loc = D->getLocation();
517     SymbolRoleSet Roles = 0;
518     SmallVector<SymbolRelation, 1> Relations;
519 
520     if (ObjCIvarDecl *ID = D->getPropertyIvarDecl())
521       Relations.push_back({(SymbolRoleSet)SymbolRole::RelationAccessorOf, ID});
522     if (Loc.isInvalid()) {
523       Loc = Container->getLocation();
524       Roles |= (SymbolRoleSet)SymbolRole::Implicit;
525     }
526     TRY_DECL(D, IndexCtx.handleDecl(D, Loc, Roles, Relations));
527 
528     if (D->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
529       return true;
530 
531     assert(D->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize);
532     SymbolRoleSet AccessorMethodRoles =
533       SymbolRoleSet(SymbolRole::Dynamic) | SymbolRoleSet(SymbolRole::Implicit);
534     if (ObjCMethodDecl *MD = PD->getGetterMethodDecl()) {
535       if (MD->isPropertyAccessor() &&
536           !hasUserDefined(MD, Container))
537         IndexCtx.handleDecl(MD, Loc, AccessorMethodRoles, {}, Container);
538     }
539     if (ObjCMethodDecl *MD = PD->getSetterMethodDecl()) {
540       if (MD->isPropertyAccessor() &&
541           !hasUserDefined(MD, Container))
542         IndexCtx.handleDecl(MD, Loc, AccessorMethodRoles, {}, Container);
543     }
544     if (ObjCIvarDecl *IvarD = D->getPropertyIvarDecl()) {
545       if (IvarD->getSynthesize()) {
546         // For synthesized ivars, use the location of its name in the
547         // corresponding @synthesize. If there isn't one, use the containing
548         // @implementation's location, rather than the property's location,
549         // otherwise the header file containing the @interface will have different
550         // indexing contents based on whether the @implementation was present or
551         // not in the translation unit.
552         SymbolRoleSet IvarRoles = 0;
553         SourceLocation IvarLoc = D->getPropertyIvarDeclLoc();
554         if (D->getLocation().isInvalid()) {
555           IvarLoc = Container->getLocation();
556           IvarRoles = (SymbolRoleSet)SymbolRole::Implicit;
557         } else if (D->getLocation() == IvarLoc) {
558           IvarRoles = (SymbolRoleSet)SymbolRole::Implicit;
559         }
560         TRY_DECL(IvarD, IndexCtx.handleDecl(IvarD, IvarLoc, IvarRoles));
561       } else {
562         IndexCtx.handleReference(IvarD, D->getPropertyIvarDeclLoc(), nullptr,
563                                  D->getDeclContext(), SymbolRoleSet());
564       }
565     }
566     return true;
567   }
568 
569   bool VisitNamespaceDecl(const NamespaceDecl *D) {
570     TRY_DECL(D, IndexCtx.handleDecl(D));
571     IndexCtx.indexDeclContext(D);
572     return true;
573   }
574 
575   bool VisitNamespaceAliasDecl(const NamespaceAliasDecl *D) {
576     TRY_DECL(D, IndexCtx.handleDecl(D));
577     IndexCtx.indexNestedNameSpecifierLoc(D->getQualifierLoc(), D);
578     IndexCtx.handleReference(D->getAliasedNamespace(), D->getTargetNameLoc(), D,
579                              D->getLexicalDeclContext());
580     return true;
581   }
582 
583   bool VisitUsingDecl(const UsingDecl *D) {
584     IndexCtx.handleDecl(D);
585 
586     const DeclContext *DC = D->getDeclContext()->getRedeclContext();
587     const NamedDecl *Parent = dyn_cast<NamedDecl>(DC);
588     IndexCtx.indexNestedNameSpecifierLoc(D->getQualifierLoc(), Parent,
589                                          D->getLexicalDeclContext());
590     for (const auto *I : D->shadows())
591       IndexCtx.handleReference(I->getUnderlyingDecl(), D->getLocation(), Parent,
592                                D->getLexicalDeclContext(), SymbolRoleSet());
593     return true;
594   }
595 
596   bool VisitUsingDirectiveDecl(const UsingDirectiveDecl *D) {
597     const DeclContext *DC = D->getDeclContext()->getRedeclContext();
598     const NamedDecl *Parent = dyn_cast<NamedDecl>(DC);
599 
600     // NNS for the local 'using namespace' directives is visited by the body
601     // visitor.
602     if (!D->getParentFunctionOrMethod())
603       IndexCtx.indexNestedNameSpecifierLoc(D->getQualifierLoc(), Parent,
604                                            D->getLexicalDeclContext());
605 
606     return IndexCtx.handleReference(D->getNominatedNamespaceAsWritten(),
607                                     D->getLocation(), Parent,
608                                     D->getLexicalDeclContext(),
609                                     SymbolRoleSet());
610   }
611 
612   bool VisitUnresolvedUsingValueDecl(const UnresolvedUsingValueDecl *D) {
613     TRY_DECL(D, IndexCtx.handleDecl(D));
614     const DeclContext *DC = D->getDeclContext()->getRedeclContext();
615     const NamedDecl *Parent = dyn_cast<NamedDecl>(DC);
616     IndexCtx.indexNestedNameSpecifierLoc(D->getQualifierLoc(), Parent,
617                                          D->getLexicalDeclContext());
618     return true;
619   }
620 
621   bool VisitUnresolvedUsingTypenameDecl(const UnresolvedUsingTypenameDecl *D) {
622     TRY_DECL(D, IndexCtx.handleDecl(D));
623     const DeclContext *DC = D->getDeclContext()->getRedeclContext();
624     const NamedDecl *Parent = dyn_cast<NamedDecl>(DC);
625     IndexCtx.indexNestedNameSpecifierLoc(D->getQualifierLoc(), Parent,
626                                          D->getLexicalDeclContext());
627     return true;
628   }
629 
630   bool VisitClassTemplateSpecializationDecl(const
631                                            ClassTemplateSpecializationDecl *D) {
632     // FIXME: Notify subsequent callbacks if info comes from implicit
633     // instantiation.
634     llvm::PointerUnion<ClassTemplateDecl *,
635                        ClassTemplatePartialSpecializationDecl *>
636         Template = D->getSpecializedTemplateOrPartial();
637     const Decl *SpecializationOf =
638         Template.is<ClassTemplateDecl *>()
639             ? (Decl *)Template.get<ClassTemplateDecl *>()
640             : Template.get<ClassTemplatePartialSpecializationDecl *>();
641     if (!D->isThisDeclarationADefinition())
642       IndexCtx.indexNestedNameSpecifierLoc(D->getQualifierLoc(), D);
643     IndexCtx.indexTagDecl(
644         D, SymbolRelation(SymbolRoleSet(SymbolRole::RelationSpecializationOf),
645                           SpecializationOf));
646     if (TypeSourceInfo *TSI = D->getTypeAsWritten())
647       IndexCtx.indexTypeSourceInfo(TSI, /*Parent=*/nullptr,
648                                    D->getLexicalDeclContext());
649     return true;
650   }
651 
652   static bool shouldIndexTemplateParameterDefaultValue(const NamedDecl *D) {
653     if (!D)
654       return false;
655     // We want to index the template parameters only once when indexing the
656     // canonical declaration.
657     if (const auto *FD = dyn_cast<FunctionDecl>(D))
658       return FD->getCanonicalDecl() == FD;
659     else if (const auto *TD = dyn_cast<TagDecl>(D))
660       return TD->getCanonicalDecl() == TD;
661     else if (const auto *VD = dyn_cast<VarDecl>(D))
662       return VD->getCanonicalDecl() == VD;
663     return true;
664   }
665 
666   bool VisitTemplateDecl(const TemplateDecl *D) {
667 
668     const NamedDecl *Parent = D->getTemplatedDecl();
669     if (!Parent)
670       return true;
671 
672     // Index the default values for the template parameters.
673     if (D->getTemplateParameters() &&
674         shouldIndexTemplateParameterDefaultValue(Parent)) {
675       const TemplateParameterList *Params = D->getTemplateParameters();
676       for (const NamedDecl *TP : *Params) {
677         if (IndexCtx.shouldIndexTemplateParameters())
678           IndexCtx.handleDecl(TP);
679         if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(TP)) {
680           if (TTP->hasDefaultArgument())
681             IndexCtx.indexTypeSourceInfo(TTP->getDefaultArgumentInfo(), Parent);
682         } else if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(TP)) {
683           if (NTTP->hasDefaultArgument())
684             IndexCtx.indexBody(NTTP->getDefaultArgument(), Parent);
685         } else if (const auto *TTPD = dyn_cast<TemplateTemplateParmDecl>(TP)) {
686           if (TTPD->hasDefaultArgument())
687             handleTemplateArgumentLoc(TTPD->getDefaultArgument(), Parent,
688                                       TP->getLexicalDeclContext());
689         }
690       }
691     }
692 
693     return Visit(Parent);
694   }
695 
696   bool VisitFriendDecl(const FriendDecl *D) {
697     if (auto ND = D->getFriendDecl()) {
698       // FIXME: Ignore a class template in a dependent context, these are not
699       // linked properly with their redeclarations, ending up with duplicate
700       // USRs.
701       // See comment "Friend templates are visible in fairly strange ways." in
702       // SemaTemplate.cpp which precedes code that prevents the friend template
703       // from becoming visible from the enclosing context.
704       if (isa<ClassTemplateDecl>(ND) && D->getDeclContext()->isDependentContext())
705         return true;
706       return Visit(ND);
707     }
708     if (auto Ty = D->getFriendType()) {
709       IndexCtx.indexTypeSourceInfo(Ty, cast<NamedDecl>(D->getDeclContext()));
710     }
711     return true;
712   }
713 
714   bool VisitImportDecl(const ImportDecl *D) {
715     return IndexCtx.importedModule(D);
716   }
717 
718   bool VisitStaticAssertDecl(const StaticAssertDecl *D) {
719     IndexCtx.indexBody(D->getAssertExpr(),
720                        dyn_cast<NamedDecl>(D->getDeclContext()),
721                        D->getLexicalDeclContext());
722     return true;
723   }
724 };
725 
726 } // anonymous namespace
727 
728 bool IndexingContext::indexDecl(const Decl *D) {
729   if (D->isImplicit() && shouldIgnoreIfImplicit(D))
730     return true;
731 
732   if (isTemplateImplicitInstantiation(D) && !shouldIndexImplicitInstantiation())
733     return true;
734 
735   IndexingDeclVisitor Visitor(*this);
736   bool ShouldContinue = Visitor.Visit(D);
737   if (!ShouldContinue)
738     return false;
739 
740   if (!Visitor.Handled && isa<DeclContext>(D))
741     return indexDeclContext(cast<DeclContext>(D));
742 
743   return true;
744 }
745 
746 bool IndexingContext::indexDeclContext(const DeclContext *DC) {
747   for (const auto *I : DC->decls())
748     if (!indexDecl(I))
749       return false;
750   return true;
751 }
752 
753 bool IndexingContext::indexTopLevelDecl(const Decl *D) {
754   if (D->getLocation().isInvalid())
755     return true;
756 
757   if (isa<ObjCMethodDecl>(D))
758     return true; // Wait for the objc container.
759 
760   return indexDecl(D);
761 }
762 
763 bool IndexingContext::indexDeclGroupRef(DeclGroupRef DG) {
764   for (DeclGroupRef::iterator I = DG.begin(), E = DG.end(); I != E; ++I)
765     if (!indexTopLevelDecl(*I))
766       return false;
767   return true;
768 }
769