1//===--- RedundantDeclarationCheck.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 "RedundantDeclarationCheck.h"
10#include "clang/AST/ASTContext.h"
11#include "clang/ASTMatchers/ASTMatchFinder.h"
12#include "clang/Lex/Lexer.h"
13
14using namespace clang::ast_matchers;
15
16namespace clang::tidy::readability {
17
18namespace {
19
20AST_MATCHER(FunctionDecl, doesDeclarationForceExternallyVisibleDefinition) {
21 return Node.doesDeclarationForceExternallyVisibleDefinition();
22}
23
24} // namespace
25
26RedundantDeclarationCheck::RedundantDeclarationCheck(StringRef Name,
27 ClangTidyContext *Context)
28 : ClangTidyCheck(Name, Context),
29 IgnoreMacros(Options.getLocalOrGlobal(LocalName: "IgnoreMacros", Default: true)) {}
30
31void RedundantDeclarationCheck::storeOptions(
32 ClangTidyOptions::OptionMap &Opts) {
33 Options.store(Options&: Opts, LocalName: "IgnoreMacros", Value: IgnoreMacros);
34}
35
36void RedundantDeclarationCheck::registerMatchers(MatchFinder *Finder) {
37 Finder->addMatcher(
38 NodeMatch: namedDecl(anyOf(varDecl(unless(isDefinition())),
39 functionDecl(unless(anyOf(
40 isDefinition(), isDefaulted(),
41 doesDeclarationForceExternallyVisibleDefinition(),
42 hasAncestor(friendDecl()))))),
43 optionally(hasParent(linkageSpecDecl().bind(ID: "extern"))))
44 .bind(ID: "Decl"),
45 Action: this);
46}
47
48void RedundantDeclarationCheck::check(const MatchFinder::MatchResult &Result) {
49 const auto *D = Result.Nodes.getNodeAs<NamedDecl>(ID: "Decl");
50 const auto *Prev = D->getPreviousDecl();
51 if (!Prev)
52 return;
53 if (!Prev->getLocation().isValid())
54 return;
55 if (Prev->getLocation() == D->getLocation())
56 return;
57 if (IgnoreMacros &&
58 (D->getLocation().isMacroID() || Prev->getLocation().isMacroID()))
59 return;
60 // Don't complain when the previous declaration is a friend declaration.
61 for (const auto &Parent : Result.Context->getParents(*Prev))
62 if (Parent.get<FriendDecl>())
63 return;
64
65 const SourceManager &SM = *Result.SourceManager;
66
67 const bool DifferentHeaders =
68 !SM.isInMainFile(Loc: D->getLocation()) &&
69 !SM.isWrittenInSameFile(Loc1: Prev->getLocation(), Loc2: D->getLocation());
70
71 bool MultiVar = false;
72 if (const auto *VD = dyn_cast<VarDecl>(Val: D)) {
73 // Is this a multivariable declaration?
74 for (const auto *Other : VD->getDeclContext()->decls()) {
75 if (Other != D && Other->getBeginLoc() == VD->getBeginLoc()) {
76 MultiVar = true;
77 break;
78 }
79 }
80 }
81
82 SourceLocation EndLoc = Lexer::getLocForEndOfToken(
83 Loc: D->getSourceRange().getEnd(), Offset: 0, SM, LangOpts: Result.Context->getLangOpts());
84 {
85 auto Diag = diag(D->getLocation(), "redundant %0 declaration") << D;
86 if (!MultiVar && !DifferentHeaders) {
87 SourceLocation BeginLoc;
88 if (const auto *Extern =
89 Result.Nodes.getNodeAs<LinkageSpecDecl>(ID: "extern");
90 Extern && !Extern->hasBraces())
91 BeginLoc = Extern->getExternLoc();
92 else
93 BeginLoc = D->getSourceRange().getBegin();
94
95 Diag << FixItHint::CreateRemoval(RemoveRange: SourceRange(BeginLoc, EndLoc));
96 }
97 }
98 diag(Prev->getLocation(), "previously declared here", DiagnosticIDs::Note);
99}
100} // namespace clang::tidy::readability
101

source code of clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp