1//===--- ConvertMemberFunctionsToStatic.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 "ConvertMemberFunctionsToStatic.h"
10#include "clang/AST/ASTContext.h"
11#include "clang/AST/DeclCXX.h"
12#include "clang/AST/RecursiveASTVisitor.h"
13#include "clang/ASTMatchers/ASTMatchFinder.h"
14#include "clang/Basic/SourceLocation.h"
15#include "clang/Lex/Lexer.h"
16
17using namespace clang::ast_matchers;
18
19namespace clang::tidy::readability {
20
21namespace {
22
23AST_MATCHER(CXXMethodDecl, isStatic) { return Node.isStatic(); }
24
25AST_MATCHER(CXXMethodDecl, hasTrivialBody) { return Node.hasTrivialBody(); }
26
27AST_MATCHER(CXXMethodDecl, isOverloadedOperator) {
28 return Node.isOverloadedOperator();
29}
30
31AST_MATCHER(CXXRecordDecl, hasAnyDependentBases) {
32 return Node.hasAnyDependentBases();
33}
34
35AST_MATCHER(CXXMethodDecl, isTemplate) {
36 return Node.getTemplatedKind() != FunctionDecl::TK_NonTemplate;
37}
38
39AST_MATCHER(CXXMethodDecl, isDependentContext) {
40 return Node.isDependentContext();
41}
42
43AST_MATCHER(CXXMethodDecl, isInsideMacroDefinition) {
44 const ASTContext &Ctxt = Finder->getASTContext();
45 return clang::Lexer::makeFileCharRange(
46 Range: clang::CharSourceRange::getCharRange(
47 Node.getTypeSourceInfo()->getTypeLoc().getSourceRange()),
48 SM: Ctxt.getSourceManager(), LangOpts: Ctxt.getLangOpts())
49 .isInvalid();
50}
51
52AST_MATCHER_P(CXXMethodDecl, hasCanonicalDecl,
53 ast_matchers::internal::Matcher<CXXMethodDecl>, InnerMatcher) {
54 return InnerMatcher.matches(Node: *Node.getCanonicalDecl(), Finder, Builder);
55}
56
57AST_MATCHER(CXXMethodDecl, usesThis) {
58 class FindUsageOfThis : public RecursiveASTVisitor<FindUsageOfThis> {
59 public:
60 bool Used = false;
61
62 bool VisitCXXThisExpr(const CXXThisExpr *E) {
63 Used = true;
64 return false; // Stop traversal.
65 }
66
67 // If we enter a class declaration, don't traverse into it as any usages of
68 // `this` will correspond to the nested class.
69 bool TraverseCXXRecordDecl(CXXRecordDecl *RD) { return true; }
70
71 } UsageOfThis;
72
73 // TraverseStmt does not modify its argument.
74 UsageOfThis.TraverseStmt(S: const_cast<Stmt *>(Node.getBody()));
75
76 return UsageOfThis.Used;
77}
78
79} // namespace
80
81void ConvertMemberFunctionsToStatic::registerMatchers(MatchFinder *Finder) {
82 Finder->addMatcher(
83 NodeMatch: cxxMethodDecl(
84 isDefinition(), isUserProvided(),
85 unless(anyOf(
86 isExpansionInSystemHeader(), isVirtual(), isStatic(),
87 hasTrivialBody(), isOverloadedOperator(), cxxConstructorDecl(),
88 cxxDestructorDecl(), cxxConversionDecl(),
89 isExplicitObjectMemberFunction(), isTemplate(),
90 isDependentContext(),
91 ofClass(InnerMatcher: anyOf(
92 isLambda(),
93 hasAnyDependentBases()) // Method might become virtual
94 // depending on template base class.
95 ),
96 isInsideMacroDefinition(),
97 hasCanonicalDecl(InnerMatcher: isInsideMacroDefinition()), usesThis())))
98 .bind(ID: "x"),
99 Action: this);
100}
101
102/// Obtain the original source code text from a SourceRange.
103static StringRef getStringFromRange(SourceManager &SourceMgr,
104 const LangOptions &LangOpts,
105 SourceRange Range) {
106 if (SourceMgr.getFileID(SpellingLoc: Range.getBegin()) !=
107 SourceMgr.getFileID(SpellingLoc: Range.getEnd()))
108 return {};
109
110 return Lexer::getSourceText(Range: CharSourceRange(Range, true), SM: SourceMgr,
111 LangOpts);
112}
113
114static SourceRange getLocationOfConst(const TypeSourceInfo *TSI,
115 SourceManager &SourceMgr,
116 const LangOptions &LangOpts) {
117 assert(TSI);
118 const auto FTL = TSI->getTypeLoc().IgnoreParens().getAs<FunctionTypeLoc>();
119 assert(FTL);
120
121 SourceRange Range{FTL.getRParenLoc().getLocWithOffset(Offset: 1),
122 FTL.getLocalRangeEnd()};
123 // Inside Range, there might be other keywords and trailing return types.
124 // Find the exact position of "const".
125 StringRef Text = getStringFromRange(SourceMgr, LangOpts, Range);
126 size_t Offset = Text.find(Str: "const");
127 if (Offset == StringRef::npos)
128 return {};
129
130 SourceLocation Start = Range.getBegin().getLocWithOffset(Offset);
131 return {Start, Start.getLocWithOffset(Offset: strlen(s: "const") - 1)};
132}
133
134void ConvertMemberFunctionsToStatic::check(
135 const MatchFinder::MatchResult &Result) {
136 const auto *Definition = Result.Nodes.getNodeAs<CXXMethodDecl>(ID: "x");
137
138 // TODO: For out-of-line declarations, don't modify the source if the header
139 // is excluded by the -header-filter option.
140 DiagnosticBuilder Diag =
141 diag(Definition->getLocation(), "method %0 can be made static")
142 << Definition;
143
144 // TODO: Would need to remove those in a fix-it.
145 if (Definition->getMethodQualifiers().hasVolatile() ||
146 Definition->getMethodQualifiers().hasRestrict() ||
147 Definition->getRefQualifier() != RQ_None)
148 return;
149
150 const CXXMethodDecl *Declaration = Definition->getCanonicalDecl();
151
152 if (Definition->isConst()) {
153 // Make sure that we either remove 'const' on both declaration and
154 // definition or emit no fix-it at all.
155 SourceRange DefConst = getLocationOfConst(Definition->getTypeSourceInfo(),
156 *Result.SourceManager,
157 Result.Context->getLangOpts());
158
159 if (DefConst.isInvalid())
160 return;
161
162 if (Declaration != Definition) {
163 SourceRange DeclConst = getLocationOfConst(
164 Declaration->getTypeSourceInfo(), *Result.SourceManager,
165 Result.Context->getLangOpts());
166
167 if (DeclConst.isInvalid())
168 return;
169 Diag << FixItHint::CreateRemoval(RemoveRange: DeclConst);
170 }
171
172 // Remove existing 'const' from both declaration and definition.
173 Diag << FixItHint::CreateRemoval(RemoveRange: DefConst);
174 }
175 Diag << FixItHint::CreateInsertion(InsertionLoc: Declaration->getBeginLoc(), Code: "static ");
176}
177
178} // namespace clang::tidy::readability
179

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