1//===--- UseTransparentFunctorsCheck.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 "UseTransparentFunctorsCheck.h"
10#include "clang/ASTMatchers/ASTMatchFinder.h"
11
12using namespace clang::ast_matchers;
13
14namespace clang::tidy::modernize {
15
16UseTransparentFunctorsCheck::UseTransparentFunctorsCheck(
17 StringRef Name, ClangTidyContext *Context)
18 : ClangTidyCheck(Name, Context), SafeMode(Options.get(LocalName: "SafeMode", Default: false)) {}
19
20void UseTransparentFunctorsCheck::storeOptions(
21 ClangTidyOptions::OptionMap &Opts) {
22 Options.store(Options&: Opts, LocalName: "SafeMode", Value: SafeMode);
23}
24
25void UseTransparentFunctorsCheck::registerMatchers(MatchFinder *Finder) {
26 const auto TransparentFunctors =
27 classTemplateSpecializationDecl(
28 unless(hasAnyTemplateArgument(InnerMatcher: refersToType(InnerMatcher: voidType()))),
29 hasAnyName("::std::plus", "::std::minus", "::std::multiplies",
30 "::std::divides", "::std::modulus", "::std::negate",
31 "::std::equal_to", "::std::not_equal_to", "::std::greater",
32 "::std::less", "::std::greater_equal", "::std::less_equal",
33 "::std::logical_and", "::std::logical_or",
34 "::std::logical_not", "::std::bit_and", "::std::bit_or",
35 "::std::bit_xor", "::std::bit_not"))
36 .bind(ID: "FunctorClass");
37
38 // Non-transparent functor mentioned as a template parameter. FIXIT.
39 Finder->addMatcher(
40 NodeMatch: loc(InnerMatcher: qualType(
41 unless(elaboratedType()),
42 hasDeclaration(InnerMatcher: classTemplateSpecializationDecl(
43 unless(hasAnyTemplateArgument(InnerMatcher: templateArgument(refersToType(
44 InnerMatcher: qualType(pointsTo(InnerMatcher: qualType(isAnyCharacter()))))))),
45 hasAnyTemplateArgument(
46 InnerMatcher: templateArgument(refersToType(InnerMatcher: qualType(hasDeclaration(
47 InnerMatcher: TransparentFunctors))))
48 .bind(ID: "Functor"))))))
49 .bind(ID: "FunctorParentLoc"),
50 Action: this);
51
52 if (SafeMode)
53 return;
54
55 // Non-transparent functor constructed. No FIXIT. There is no easy way
56 // to rule out the problematic char* vs string case.
57 Finder->addMatcher(NodeMatch: cxxConstructExpr(hasDeclaration(InnerMatcher: cxxMethodDecl(
58 ofClass(InnerMatcher: TransparentFunctors))),
59 unless(isInTemplateInstantiation()))
60 .bind(ID: "FuncInst"),
61 Action: this);
62}
63
64static const StringRef Message = "prefer transparent functors '%0<>'";
65
66template <typename T> static T getInnerTypeLocAs(TypeLoc Loc) {
67 T Result;
68 while (Result.isNull() && !Loc.isNull()) {
69 Result = Loc.getAs<T>();
70 Loc = Loc.getNextTypeLoc();
71 }
72 return Result;
73}
74
75void UseTransparentFunctorsCheck::check(
76 const MatchFinder::MatchResult &Result) {
77 const auto *FuncClass =
78 Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>(ID: "FunctorClass");
79 if (const auto *FuncInst =
80 Result.Nodes.getNodeAs<CXXConstructExpr>(ID: "FuncInst")) {
81 diag(Loc: FuncInst->getBeginLoc(), Description: Message) << FuncClass->getName();
82 return;
83 }
84
85 const auto *Functor = Result.Nodes.getNodeAs<TemplateArgument>(ID: "Functor");
86 const auto FunctorParentLoc =
87 Result.Nodes.getNodeAs<TypeLoc>(ID: "FunctorParentLoc")
88 ->getAs<TemplateSpecializationTypeLoc>();
89
90 if (!FunctorParentLoc)
91 return;
92
93 unsigned ArgNum = 0;
94 const auto *FunctorParentType =
95 FunctorParentLoc.getType()->castAs<TemplateSpecializationType>();
96 for (; ArgNum < FunctorParentType->template_arguments().size(); ++ArgNum) {
97 const TemplateArgument &Arg =
98 FunctorParentType->template_arguments()[ArgNum];
99 if (Arg.getKind() != TemplateArgument::Type)
100 continue;
101 QualType ParentArgType = Arg.getAsType();
102 if (ParentArgType->isRecordType() &&
103 ParentArgType->getAsCXXRecordDecl() ==
104 Functor->getAsType()->getAsCXXRecordDecl())
105 break;
106 }
107 // Functor is a default template argument.
108 if (ArgNum == FunctorParentType->template_arguments().size())
109 return;
110 TemplateArgumentLoc FunctorLoc = FunctorParentLoc.getArgLoc(i: ArgNum);
111 auto FunctorTypeLoc = getInnerTypeLocAs<TemplateSpecializationTypeLoc>(
112 Loc: FunctorLoc.getTypeSourceInfo()->getTypeLoc());
113 if (FunctorTypeLoc.isNull())
114 return;
115
116 SourceLocation ReportLoc = FunctorLoc.getLocation();
117 if (ReportLoc.isInvalid())
118 return;
119 diag(Loc: ReportLoc, Description: Message) << FuncClass->getName()
120 << FixItHint::CreateRemoval(
121 RemoveRange: FunctorTypeLoc.getArgLoc(i: 0).getSourceRange());
122}
123
124} // namespace clang::tidy::modernize
125

source code of clang-tools-extra/clang-tidy/modernize/UseTransparentFunctorsCheck.cpp