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 
18 namespace clang {
19 
20 namespace {
21 
22 struct Builder : RecursiveASTVisitor<Builder> {
23   ASTImporterLookupTable &LT;
24   Builder(ASTImporterLookupTable &LT) : LT(LT) {}
25   bool VisitNamedDecl(NamedDecl *D) {
26     LT.add(D);
27     return true;
28   }
29   // In most cases the FriendDecl contains the declaration of the befriended
30   // class as a child node, so it is discovered during the recursive
31   // visitation. However, there are cases when the befriended class is not a
32   // child, thus it must be fetched explicitly from the FriendDecl, and only
33   // then can we add it to the lookup table.
34   bool VisitFriendDecl(FriendDecl *D) {
35     if (D->getFriendType()) {
36       QualType Ty = D->getFriendType()->getType();
37       if (isa<ElaboratedType>(Ty))
38         Ty = cast<ElaboratedType>(Ty)->getNamedType();
39       // A FriendDecl with a dependent type (e.g. ClassTemplateSpecialization)
40       // always has that decl as child node.
41       // However, there are non-dependent cases which does not have the
42       // type as a child node. We have to dig up that type now.
43       if (!Ty->isDependentType()) {
44         if (const auto *RTy = dyn_cast<RecordType>(Ty))
45           LT.add(RTy->getAsCXXRecordDecl());
46         else if (const auto *SpecTy = dyn_cast<TemplateSpecializationType>(Ty))
47           LT.add(SpecTy->getAsCXXRecordDecl());
48         else if (isa<TypedefType>(Ty)) {
49           // We do not put friend typedefs to the lookup table because
50           // ASTImporter does not organize typedefs into redecl chains.
51         } else {
52           llvm_unreachable("Unhandled type of friend class");
53         }
54       }
55     }
56     return true;
57   }
58 
59   // Override default settings of base.
60   bool shouldVisitTemplateInstantiations() const { return true; }
61   bool shouldVisitImplicitCode() const { return true; }
62 };
63 
64 } // anonymous namespace
65 
66 ASTImporterLookupTable::ASTImporterLookupTable(TranslationUnitDecl &TU) {
67   Builder B(*this);
68   B.TraverseDecl(&TU);
69 }
70 
71 void ASTImporterLookupTable::add(DeclContext *DC, NamedDecl *ND) {
72   DeclList &Decls = LookupTable[DC][ND->getDeclName()];
73   // Inserts if and only if there is no element in the container equal to it.
74   Decls.insert(ND);
75 }
76 
77 void ASTImporterLookupTable::remove(DeclContext *DC, NamedDecl *ND) {
78   DeclList &Decls = LookupTable[DC][ND->getDeclName()];
79   bool EraseResult = Decls.remove(ND);
80   (void)EraseResult;
81   assert(EraseResult == true && "Trying to remove not contained Decl");
82 }
83 
84 void ASTImporterLookupTable::add(NamedDecl *ND) {
85   assert(ND);
86   DeclContext *DC = ND->getDeclContext()->getPrimaryContext();
87   add(DC, ND);
88   DeclContext *ReDC = DC->getRedeclContext()->getPrimaryContext();
89   if (DC != ReDC)
90     add(ReDC, ND);
91 }
92 
93 void ASTImporterLookupTable::remove(NamedDecl *ND) {
94   assert(ND);
95   DeclContext *DC = ND->getDeclContext()->getPrimaryContext();
96   remove(DC, ND);
97   DeclContext *ReDC = DC->getRedeclContext()->getPrimaryContext();
98   if (DC != ReDC)
99     remove(ReDC, ND);
100 }
101 
102 ASTImporterLookupTable::LookupResult
103 ASTImporterLookupTable::lookup(DeclContext *DC, DeclarationName Name) const {
104   auto DCI = LookupTable.find(DC->getPrimaryContext());
105   if (DCI == LookupTable.end())
106     return {};
107 
108   const auto &FoundNameMap = DCI->second;
109   auto NamesI = FoundNameMap.find(Name);
110   if (NamesI == FoundNameMap.end())
111     return {};
112 
113   return NamesI->second;
114 }
115 
116 void ASTImporterLookupTable::dump(DeclContext *DC) const {
117   auto DCI = LookupTable.find(DC->getPrimaryContext());
118   if (DCI == LookupTable.end())
119     llvm::errs() << "empty\n";
120   const auto &FoundNameMap = DCI->second;
121   for (const auto &Entry : FoundNameMap) {
122     DeclarationName Name = Entry.first;
123     llvm::errs() << "==== Name: ";
124     Name.dump();
125     const DeclList& List = Entry.second;
126     for (NamedDecl *ND : List) {
127       ND->dump();
128     }
129   }
130 }
131 
132 void ASTImporterLookupTable::dump() const {
133   for (const auto &Entry : LookupTable) {
134     DeclContext *DC = Entry.first;
135     StringRef Primary = DC->getPrimaryContext() ? " primary" : "";
136     llvm::errs() << "== DC:" << cast<Decl>(DC) << Primary << "\n";
137     dump(DC);
138   }
139 }
140 
141 } // namespace clang
142