1 //===- ASTImporterLookupTable.cpp - ASTImporter specific lookup -----------===//
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 defines the ASTImporterLookupTable class which implements a
10 //  lookup procedure for the import mechanism.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/AST/ASTImporterLookupTable.h"
15 #include "clang/AST/Decl.h"
16 #include "clang/AST/RecursiveASTVisitor.h"
17 #include "llvm/Support/FormatVariadic.h"
18 
19 namespace clang {
20 
21 namespace {
22 
23 struct Builder : RecursiveASTVisitor<Builder> {
24   ASTImporterLookupTable &LT;
25   Builder(ASTImporterLookupTable &LT) : LT(LT) {}
26 
27   bool VisitTypedefNameDecl(TypedefNameDecl *D) {
28     QualType Ty = D->getUnderlyingType();
29     Ty = Ty.getCanonicalType();
30     if (const auto *RTy = dyn_cast<RecordType>(Ty)) {
31       LT.add(RTy->getAsRecordDecl());
32       // iterate over the field decls, adding them
33       for (auto *it : RTy->getAsRecordDecl()->fields()) {
34         LT.add(it);
35       }
36     }
37     return true;
38   }
39 
40   bool VisitNamedDecl(NamedDecl *D) {
41     LT.add(D);
42     return true;
43   }
44   // In most cases the FriendDecl contains the declaration of the befriended
45   // class as a child node, so it is discovered during the recursive
46   // visitation. However, there are cases when the befriended class is not a
47   // child, thus it must be fetched explicitly from the FriendDecl, and only
48   // then can we add it to the lookup table.
49   bool VisitFriendDecl(FriendDecl *D) {
50     if (D->getFriendType()) {
51       QualType Ty = D->getFriendType()->getType();
52       if (isa<ElaboratedType>(Ty))
53         Ty = cast<ElaboratedType>(Ty)->getNamedType();
54       // A FriendDecl with a dependent type (e.g. ClassTemplateSpecialization)
55       // always has that decl as child node.
56       // However, there are non-dependent cases which does not have the
57       // type as a child node. We have to dig up that type now.
58       if (!Ty->isDependentType()) {
59         if (const auto *RTy = dyn_cast<RecordType>(Ty))
60           LT.add(RTy->getAsCXXRecordDecl());
61         else if (const auto *SpecTy = dyn_cast<TemplateSpecializationType>(Ty))
62           LT.add(SpecTy->getAsCXXRecordDecl());
63         else if (const auto *SubstTy =
64                      dyn_cast<SubstTemplateTypeParmType>(Ty)) {
65           if (SubstTy->getAsCXXRecordDecl())
66             LT.add(SubstTy->getAsCXXRecordDecl());
67         } else if (isa<TypedefType>(Ty)) {
68           // We do not put friend typedefs to the lookup table because
69           // ASTImporter does not organize typedefs into redecl chains.
70         } else {
71           llvm_unreachable("Unhandled type of friend class");
72         }
73       }
74     }
75     return true;
76   }
77 
78   // Override default settings of base.
79   bool shouldVisitTemplateInstantiations() const { return true; }
80   bool shouldVisitImplicitCode() const { return true; }
81 };
82 
83 } // anonymous namespace
84 
85 ASTImporterLookupTable::ASTImporterLookupTable(TranslationUnitDecl &TU) {
86   Builder B(*this);
87   B.TraverseDecl(&TU);
88 }
89 
90 void ASTImporterLookupTable::add(DeclContext *DC, NamedDecl *ND) {
91   DeclList &Decls = LookupTable[DC][ND->getDeclName()];
92   // Inserts if and only if there is no element in the container equal to it.
93   Decls.insert(ND);
94 }
95 
96 void ASTImporterLookupTable::remove(DeclContext *DC, NamedDecl *ND) {
97   const DeclarationName Name = ND->getDeclName();
98   DeclList &Decls = LookupTable[DC][Name];
99   bool EraseResult = Decls.remove(ND);
100   (void)EraseResult;
101 #ifndef NDEBUG
102   if (!EraseResult) {
103     std::string Message =
104         llvm::formatv("Trying to remove not contained Decl '{0}' of type {1}",
105                       Name.getAsString(), DC->getDeclKindName())
106             .str();
107     llvm_unreachable(Message.c_str());
108   }
109 #endif
110 }
111 
112 void ASTImporterLookupTable::add(NamedDecl *ND) {
113   assert(ND);
114   DeclContext *DC = ND->getDeclContext()->getPrimaryContext();
115   add(DC, ND);
116   DeclContext *ReDC = DC->getRedeclContext()->getPrimaryContext();
117   if (DC != ReDC)
118     add(ReDC, ND);
119 }
120 
121 void ASTImporterLookupTable::remove(NamedDecl *ND) {
122   assert(ND);
123   DeclContext *DC = ND->getDeclContext()->getPrimaryContext();
124   remove(DC, ND);
125   DeclContext *ReDC = DC->getRedeclContext()->getPrimaryContext();
126   if (DC != ReDC)
127     remove(ReDC, ND);
128 }
129 
130 void ASTImporterLookupTable::update(NamedDecl *ND, DeclContext *OldDC) {
131   assert(OldDC != ND->getDeclContext() &&
132          "DeclContext should be changed before update");
133   if (contains(ND->getDeclContext(), ND)) {
134     assert(!contains(OldDC, ND) &&
135            "Decl should not be found in the old context if already in the new");
136     return;
137   }
138 
139   remove(OldDC, ND);
140   add(ND);
141 }
142 
143 void ASTImporterLookupTable::updateForced(NamedDecl *ND, DeclContext *OldDC) {
144   LookupTable[OldDC][ND->getDeclName()].remove(ND);
145   add(ND);
146 }
147 
148 ASTImporterLookupTable::LookupResult
149 ASTImporterLookupTable::lookup(DeclContext *DC, DeclarationName Name) const {
150   auto DCI = LookupTable.find(DC->getPrimaryContext());
151   if (DCI == LookupTable.end())
152     return {};
153 
154   const auto &FoundNameMap = DCI->second;
155   auto NamesI = FoundNameMap.find(Name);
156   if (NamesI == FoundNameMap.end())
157     return {};
158 
159   return NamesI->second;
160 }
161 
162 bool ASTImporterLookupTable::contains(DeclContext *DC, NamedDecl *ND) const {
163   return lookup(DC, ND->getDeclName()).contains(ND);
164 }
165 
166 void ASTImporterLookupTable::dump(DeclContext *DC) const {
167   auto DCI = LookupTable.find(DC->getPrimaryContext());
168   if (DCI == LookupTable.end())
169     llvm::errs() << "empty\n";
170   const auto &FoundNameMap = DCI->second;
171   for (const auto &Entry : FoundNameMap) {
172     DeclarationName Name = Entry.first;
173     llvm::errs() << "==== Name: ";
174     Name.dump();
175     const DeclList& List = Entry.second;
176     for (NamedDecl *ND : List) {
177       ND->dump();
178     }
179   }
180 }
181 
182 void ASTImporterLookupTable::dump() const {
183   for (const auto &Entry : LookupTable) {
184     DeclContext *DC = Entry.first;
185     StringRef Primary = DC->getPrimaryContext() ? " primary" : "";
186     llvm::errs() << "== DC:" << cast<Decl>(DC) << Primary << "\n";
187     dump(DC);
188   }
189 }
190 
191 } // namespace clang
192