1 //===---------- UsingInserter.cpp - clang-tidy ----------------------------===//
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 "UsingInserter.h"
10
11 #include "ASTUtils.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/ASTMatchers/ASTMatchers.h"
14 #include "clang/Lex/Lexer.h"
15 #include <optional>
16
17 namespace clang::tidy::utils {
18
19 using namespace ast_matchers;
20
getUnqualifiedName(StringRef QualifiedName)21 static StringRef getUnqualifiedName(StringRef QualifiedName) {
22 size_t LastSeparatorPos = QualifiedName.rfind("::");
23 if (LastSeparatorPos == StringRef::npos)
24 return QualifiedName;
25 return QualifiedName.drop_front(LastSeparatorPos + 2);
26 }
27
UsingInserter(const SourceManager & SourceMgr)28 UsingInserter::UsingInserter(const SourceManager &SourceMgr)
29 : SourceMgr(SourceMgr) {}
30
createUsingDeclaration(ASTContext & Context,const Stmt & Statement,StringRef QualifiedName)31 std::optional<FixItHint> UsingInserter::createUsingDeclaration(
32 ASTContext &Context, const Stmt &Statement, StringRef QualifiedName) {
33 StringRef UnqualifiedName = getUnqualifiedName(QualifiedName);
34 const FunctionDecl *Function = getSurroundingFunction(Context, Statement);
35 if (!Function)
36 return std::nullopt;
37
38 if (AddedUsing.count(std::make_pair(Function, QualifiedName.str())) != 0)
39 return std::nullopt;
40
41 SourceLocation InsertLoc = Lexer::getLocForEndOfToken(
42 Function->getBody()->getBeginLoc(), 0, SourceMgr, Context.getLangOpts());
43
44 // Only use using declarations in the main file, not in includes.
45 if (SourceMgr.getFileID(InsertLoc) != SourceMgr.getMainFileID())
46 return std::nullopt;
47
48 // FIXME: This declaration could be masked. Investigate if
49 // there is a way to avoid using Sema.
50 bool AlreadyHasUsingDecl =
51 !match(stmt(hasAncestor(decl(has(usingDecl(hasAnyUsingShadowDecl(
52 hasTargetDecl(hasName(QualifiedName.str())))))))),
53 Statement, Context)
54 .empty();
55 if (AlreadyHasUsingDecl) {
56 AddedUsing.emplace(Function, QualifiedName.str());
57 return std::nullopt;
58 }
59 // Find conflicting declarations and references.
60 auto ConflictingDecl = namedDecl(hasName(UnqualifiedName));
61 bool HasConflictingDeclaration =
62 !match(findAll(ConflictingDecl), *Function, Context).empty();
63 bool HasConflictingDeclRef =
64 !match(findAll(declRefExpr(to(ConflictingDecl))), *Function, Context)
65 .empty();
66 if (HasConflictingDeclaration || HasConflictingDeclRef)
67 return std::nullopt;
68
69 std::string Declaration =
70 (llvm::Twine("\nusing ") + QualifiedName + ";").str();
71
72 AddedUsing.emplace(Function, QualifiedName.str());
73 return FixItHint::CreateInsertion(InsertLoc, Declaration);
74 }
75
getShortName(ASTContext & Context,const Stmt & Statement,StringRef QualifiedName)76 StringRef UsingInserter::getShortName(ASTContext &Context,
77 const Stmt &Statement,
78 StringRef QualifiedName) {
79 const FunctionDecl *Function = getSurroundingFunction(Context, Statement);
80 if (AddedUsing.count(NameInFunction(Function, QualifiedName.str())) != 0)
81 return getUnqualifiedName(QualifiedName);
82 return QualifiedName;
83 }
84
85 } // namespace clang::tidy::utils
86