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
19namespace clang {
20
21namespace {
22
23struct 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>(Val&: Ty)) {
31 LT.add(ND: RTy->getAsRecordDecl());
32 // iterate over the field decls, adding them
33 for (auto *it : RTy->getAsRecordDecl()->fields()) {
34 LT.add(ND: it);
35 }
36 }
37 return true;
38 }
39
40 bool VisitNamedDecl(NamedDecl *D) {
41 LT.add(ND: 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>(Val: Ty))
53 Ty = cast<ElaboratedType>(Val&: 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>(Val&: Ty))
60 LT.add(ND: RTy->getAsCXXRecordDecl());
61 else if (const auto *SpecTy = dyn_cast<TemplateSpecializationType>(Val&: Ty))
62 LT.add(ND: SpecTy->getAsCXXRecordDecl());
63 else if (const auto *SubstTy =
64 dyn_cast<SubstTemplateTypeParmType>(Val&: Ty)) {
65 if (SubstTy->getAsCXXRecordDecl())
66 LT.add(ND: SubstTy->getAsCXXRecordDecl());
67 } else if (isa<TypedefType>(Val: Ty)) {
68 // We do not put friend typedefs to the lookup table because
69 // ASTImporter does not organize typedefs into redecl chains.
70 } else if (isa<UsingType>(Val: Ty)) {
71 // Similar to TypedefType, not putting into lookup table.
72 } else {
73 llvm_unreachable("Unhandled type of friend class");
74 }
75 }
76 }
77 return true;
78 }
79
80 // Override default settings of base.
81 bool shouldVisitTemplateInstantiations() const { return true; }
82 bool shouldVisitImplicitCode() const { return true; }
83};
84
85} // anonymous namespace
86
87ASTImporterLookupTable::ASTImporterLookupTable(TranslationUnitDecl &TU) {
88 Builder B(*this);
89 B.TraverseDecl(D: &TU);
90 // The VaList declaration may be created on demand only or not traversed.
91 // To ensure it is present and found during import, add it to the table now.
92 if (auto *D =
93 dyn_cast_or_null<NamedDecl>(Val: TU.getASTContext().getVaListTagDecl())) {
94 // On some platforms (AArch64) the VaList declaration can be inside a 'std'
95 // namespace. This is handled specially and not visible by AST traversal.
96 // ASTImporter must be able to find this namespace to import the VaList
97 // declaration (and the namespace) correctly.
98 if (auto *Ns = dyn_cast<NamespaceDecl>(Val: D->getDeclContext()))
99 add(DC: &TU, ND: Ns);
100 add(DC: D->getDeclContext(), ND: D);
101 }
102}
103
104void ASTImporterLookupTable::add(DeclContext *DC, NamedDecl *ND) {
105 DeclList &Decls = LookupTable[DC][ND->getDeclName()];
106 // Inserts if and only if there is no element in the container equal to it.
107 Decls.insert(X: ND);
108}
109
110void ASTImporterLookupTable::remove(DeclContext *DC, NamedDecl *ND) {
111 const DeclarationName Name = ND->getDeclName();
112 DeclList &Decls = LookupTable[DC][Name];
113 bool EraseResult = Decls.remove(X: ND);
114 (void)EraseResult;
115#ifndef NDEBUG
116 if (!EraseResult) {
117 std::string Message =
118 llvm::formatv(
119 "Trying to remove not contained Decl '{0}' of type {1} from a {2}",
120 Name.getAsString(), ND->getDeclKindName(), DC->getDeclKindName())
121 .str();
122 llvm_unreachable(Message.c_str());
123 }
124#endif
125}
126
127void ASTImporterLookupTable::add(NamedDecl *ND) {
128 assert(ND);
129 DeclContext *DC = ND->getDeclContext();
130 add(DC, ND);
131 DeclContext *ReDC = DC->getRedeclContext();
132 if (DC != ReDC)
133 add(DC: ReDC, ND);
134}
135
136void ASTImporterLookupTable::remove(NamedDecl *ND) {
137 assert(ND);
138 DeclContext *DC = ND->getDeclContext();
139 remove(DC, ND);
140 DeclContext *ReDC = DC->getRedeclContext();
141 if (DC != ReDC)
142 remove(DC: ReDC, ND);
143}
144
145void ASTImporterLookupTable::update(NamedDecl *ND, DeclContext *OldDC) {
146 assert(OldDC != ND->getDeclContext() &&
147 "DeclContext should be changed before update");
148 if (contains(DC: ND->getDeclContext(), ND)) {
149 assert(!contains(OldDC, ND) &&
150 "Decl should not be found in the old context if already in the new");
151 return;
152 }
153
154 remove(DC: OldDC, ND);
155 add(ND);
156}
157
158void ASTImporterLookupTable::updateForced(NamedDecl *ND, DeclContext *OldDC) {
159 LookupTable[OldDC][ND->getDeclName()].remove(X: ND);
160 add(ND);
161}
162
163ASTImporterLookupTable::LookupResult
164ASTImporterLookupTable::lookup(DeclContext *DC, DeclarationName Name) const {
165 auto DCI = LookupTable.find(Val: DC);
166 if (DCI == LookupTable.end())
167 return {};
168
169 const auto &FoundNameMap = DCI->second;
170 auto NamesI = FoundNameMap.find(Val: Name);
171 if (NamesI == FoundNameMap.end())
172 return {};
173
174 return NamesI->second;
175}
176
177bool ASTImporterLookupTable::contains(DeclContext *DC, NamedDecl *ND) const {
178 return lookup(DC, Name: ND->getDeclName()).contains(key: ND);
179}
180
181void ASTImporterLookupTable::dump(DeclContext *DC) const {
182 auto DCI = LookupTable.find(Val: DC);
183 if (DCI == LookupTable.end())
184 llvm::errs() << "empty\n";
185 const auto &FoundNameMap = DCI->second;
186 for (const auto &Entry : FoundNameMap) {
187 DeclarationName Name = Entry.first;
188 llvm::errs() << "==== Name: ";
189 Name.dump();
190 const DeclList& List = Entry.second;
191 for (NamedDecl *ND : List) {
192 ND->dump();
193 }
194 }
195}
196
197void ASTImporterLookupTable::dump() const {
198 for (const auto &Entry : LookupTable) {
199 DeclContext *DC = Entry.first;
200 llvm::errs() << "== DC:" << cast<Decl>(Val: DC) << "\n";
201 dump(DC);
202 }
203}
204
205} // namespace clang
206