| 1 | //===- ASTImporterLookupTable.h - ASTImporter specific lookup--*- C++ -*---===// |
|---|---|
| 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 | #ifndef LLVM_CLANG_AST_ASTIMPORTERLOOKUPTABLE_H |
| 15 | #define LLVM_CLANG_AST_ASTIMPORTERLOOKUPTABLE_H |
| 16 | |
| 17 | #include "clang/AST/DeclBase.h" // lookup_result |
| 18 | #include "clang/AST/DeclarationName.h" |
| 19 | #include "llvm/ADT/DenseMap.h" |
| 20 | #include "llvm/ADT/SetVector.h" |
| 21 | |
| 22 | namespace clang { |
| 23 | |
| 24 | class ASTContext; |
| 25 | class NamedDecl; |
| 26 | class DeclContext; |
| 27 | |
| 28 | // There are certain cases when normal C/C++ lookup (localUncachedLookup) |
| 29 | // does not find AST nodes. E.g.: |
| 30 | // Example 1: |
| 31 | // template <class T> |
| 32 | // struct X { |
| 33 | // friend void foo(); // this is never found in the DC of the TU. |
| 34 | // }; |
| 35 | // Example 2: |
| 36 | // // The fwd decl to Foo is not found in the lookupPtr of the DC of the |
| 37 | // // translation unit decl. |
| 38 | // // Here we could find the node by doing a traverse throught the list of |
| 39 | // // the Decls in the DC, but that would not scale. |
| 40 | // struct A { struct Foo *p; }; |
| 41 | // This is a severe problem because the importer decides if it has to create a |
| 42 | // new Decl or not based on the lookup results. |
| 43 | // To overcome these cases we need an importer specific lookup table which |
| 44 | // holds every node and we are not interested in any C/C++ specific visibility |
| 45 | // considerations. Simply, we must know if there is an existing Decl in a |
| 46 | // given DC. Once we found it then we can handle any visibility related tasks. |
| 47 | class ASTImporterLookupTable { |
| 48 | |
| 49 | // We store a list of declarations for each name. |
| 50 | // And we collect these lists for each DeclContext. |
| 51 | // We could have a flat map with (DeclContext, Name) tuple as key, but a two |
| 52 | // level map seems easier to handle. |
| 53 | using DeclList = llvm::SmallSetVector<NamedDecl *, 2>; |
| 54 | using NameMap = llvm::SmallDenseMap<DeclarationName, DeclList, 4>; |
| 55 | using DCMap = llvm::DenseMap<DeclContext *, NameMap>; |
| 56 | |
| 57 | void add(DeclContext *DC, NamedDecl *ND); |
| 58 | void remove(DeclContext *DC, NamedDecl *ND); |
| 59 | |
| 60 | DCMap LookupTable; |
| 61 | |
| 62 | public: |
| 63 | ASTImporterLookupTable(TranslationUnitDecl &TU); |
| 64 | void add(NamedDecl *ND); |
| 65 | void remove(NamedDecl *ND); |
| 66 | using LookupResult = DeclList; |
| 67 | LookupResult lookup(DeclContext *DC, DeclarationName Name) const; |
| 68 | void dump(DeclContext *DC) const; |
| 69 | void dump() const; |
| 70 | }; |
| 71 | |
| 72 | } // namespace clang |
| 73 | |
| 74 | #endif // LLVM_CLANG_AST_ASTIMPORTERLOOKUPTABLE_H |
| 75 |