clang-tools 6.0.0

PostfixOperatorCheck.cpp
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1 //===--- PostfixOperatorCheck.cpp - clang-tidy-----------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "PostfixOperatorCheck.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/Lex/Lexer.h"
14
15 using namespace clang::ast_matchers;
16
17 namespace clang {
18 namespace tidy {
19 namespace cert {
20
21 void PostfixOperatorCheck::registerMatchers(MatchFinder *Finder) {
22 if (!getLangOpts().CPlusPlus)
23 return;
24
25 Finder->addMatcher(functionDecl(anyOf(hasOverloadedOperatorName("++"),
26 hasOverloadedOperatorName("--")))
27 .bind("decl"),
28 this);
29 }
30
31 void PostfixOperatorCheck::check(const MatchFinder::MatchResult &Result) {
32 const auto *FuncDecl = Result.Nodes.getNodeAs<FunctionDecl>("decl");
33
34 bool HasThis = false;
35 if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(FuncDecl))
36 HasThis = MethodDecl->isInstance();
37
38 // Check if the operator is a postfix one.
39 if (FuncDecl->getNumParams() != (HasThis ? 1 : 2))
40 return;
41
42 SourceRange ReturnRange = FuncDecl->getReturnTypeSourceRange();
43 SourceLocation Location = ReturnRange.getBegin();
44 if (!Location.isValid())
45 return;
46
47 QualType ReturnType = FuncDecl->getReturnType();
48
49 // Warn when the operators return a reference.
50 if (const auto *RefType = ReturnType->getAs<ReferenceType>()) {
51 auto Diag = diag(Location, "overloaded %0 returns a reference instead of a "
52 "constant object type")
53 << FuncDecl;
54
55 if (Location.isMacroID() || ReturnType->getAs<TypedefType>() ||
56 RefType->getPointeeTypeAsWritten()->getAs<TypedefType>())
57 return;
58
59 QualType ReplaceType =
60 ReturnType.getNonReferenceType().getLocalUnqualifiedType();
61 // The getReturnTypeSourceRange omits the qualifiers. We do not want to
62 // duplicate the const.
63 if (!ReturnType->getPointeeType().isConstQualified())
64 ReplaceType.addConst();
65
66 Diag << FixItHint::CreateReplacement(
67 ReturnRange,
68 ReplaceType.getAsString(Result.Context->getPrintingPolicy()) + " ");
69
70 return;
71 }
72
73 if (ReturnType.isConstQualified() || ReturnType->isBuiltinType() ||
74 ReturnType->isPointerType())
75 return;
76
77 auto Diag =
78 diag(Location, "overloaded %0 returns a non-constant object instead of a "
79 "constant object type")
80 << FuncDecl;
81
82 if (!Location.isMacroID() && !ReturnType->getAs<TypedefType>())
83 Diag << FixItHint::CreateInsertion(Location, "const ");
84 }
85
86 } // namespace cert
87 } // namespace tidy
88 } // namespace clang
clang::ast_matchers
Definition: ClangTidyDiagnosticConsumer.h:27
PostfixOperatorCheck.h
clang
Definition: AndroidTidyModule.cpp:28
Location
Definition: Modularize.cpp:384