clang-tools  11.0.0git
ConvertMemberFunctionsToStatic.cpp
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1 //===--- ConvertMemberFunctionsToStatic.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 
11 #include "clang/AST/ASTContext.h"
12 #include "clang/AST/DeclCXX.h"
13 #include "clang/AST/RecursiveASTVisitor.h"
14 #include "clang/ASTMatchers/ASTMatchFinder.h"
15 #include "clang/Basic/SourceLocation.h"
16 #include "clang/Lex/Lexer.h"
17 
18 using namespace clang::ast_matchers;
19 
20 namespace clang {
21 namespace tidy {
22 namespace readability {
23 
24 AST_MATCHER(CXXMethodDecl, isStatic) { return Node.isStatic(); }
25 
26 AST_MATCHER(CXXMethodDecl, hasTrivialBody) { return Node.hasTrivialBody(); }
27 
28 AST_MATCHER(CXXMethodDecl, isOverloadedOperator) {
29  return Node.isOverloadedOperator();
30 }
31 
32 AST_MATCHER(CXXRecordDecl, hasAnyDependentBases) {
33  return Node.hasAnyDependentBases();
34 }
35 
36 AST_MATCHER(CXXMethodDecl, isTemplate) {
37  return Node.getTemplatedKind() != FunctionDecl::TK_NonTemplate;
38 }
39 
40 AST_MATCHER(CXXMethodDecl, isDependentContext) {
41  return Node.isDependentContext();
42 }
43 
44 AST_MATCHER(CXXMethodDecl, isInsideMacroDefinition) {
45  const ASTContext &Ctxt = Finder->getASTContext();
46  return clang::Lexer::makeFileCharRange(
47  clang::CharSourceRange::getCharRange(
48  Node.getTypeSourceInfo()->getTypeLoc().getSourceRange()),
49  Ctxt.getSourceManager(), Ctxt.getLangOpts())
50  .isInvalid();
51 }
52 
53 AST_MATCHER_P(CXXMethodDecl, hasCanonicalDecl,
54  ast_matchers::internal::Matcher<CXXMethodDecl>, InnerMatcher) {
55  return InnerMatcher.matches(*Node.getCanonicalDecl(), Finder, Builder);
56 }
57 
58 AST_MATCHER(CXXMethodDecl, usesThis) {
59  class FindUsageOfThis : public RecursiveASTVisitor<FindUsageOfThis> {
60  public:
61  bool Used = false;
62 
63  bool VisitCXXThisExpr(const CXXThisExpr *E) {
64  Used = true;
65  return false; // Stop traversal.
66  }
67  } UsageOfThis;
68 
69  // TraverseStmt does not modify its argument.
70  UsageOfThis.TraverseStmt(const_cast<Stmt *>(Node.getBody()));
71 
72  return UsageOfThis.Used;
73 }
74 
75 void ConvertMemberFunctionsToStatic::registerMatchers(MatchFinder *Finder) {
76  Finder->addMatcher(
77  cxxMethodDecl(
78  isDefinition(), isUserProvided(),
79  unless(anyOf(
80  isExpansionInSystemHeader(), isVirtual(), isStatic(),
81  hasTrivialBody(), isOverloadedOperator(), cxxConstructorDecl(),
82  cxxDestructorDecl(), cxxConversionDecl(), isTemplate(),
83  isDependentContext(),
84  ofClass(anyOf(
85  isLambda(),
86  hasAnyDependentBases()) // Method might become virtual
87  // depending on template base class.
88  ),
89  isInsideMacroDefinition(),
90  hasCanonicalDecl(isInsideMacroDefinition()), usesThis())))
91  .bind("x"),
92  this);
93 }
94 
95 /// Obtain the original source code text from a SourceRange.
96 static StringRef getStringFromRange(SourceManager &SourceMgr,
97  const LangOptions &LangOpts,
98  SourceRange Range) {
99  if (SourceMgr.getFileID(Range.getBegin()) !=
100  SourceMgr.getFileID(Range.getEnd()))
101  return {};
102 
103  return Lexer::getSourceText(CharSourceRange(Range, true), SourceMgr,
104  LangOpts);
105 }
106 
107 static SourceRange getLocationOfConst(const TypeSourceInfo *TSI,
108  SourceManager &SourceMgr,
109  const LangOptions &LangOpts) {
110  assert(TSI);
111  const auto FTL = TSI->getTypeLoc().IgnoreParens().getAs<FunctionTypeLoc>();
112  assert(FTL);
113 
114  SourceRange Range{FTL.getRParenLoc().getLocWithOffset(1),
115  FTL.getLocalRangeEnd()};
116  // Inside Range, there might be other keywords and trailing return types.
117  // Find the exact position of "const".
118  StringRef Text = getStringFromRange(SourceMgr, LangOpts, Range);
119  size_t Offset = Text.find("const");
120  if (Offset == StringRef::npos)
121  return {};
122 
123  SourceLocation Start = Range.getBegin().getLocWithOffset(Offset);
124  return {Start, Start.getLocWithOffset(strlen("const") - 1)};
125 }
126 
127 void ConvertMemberFunctionsToStatic::check(
128  const MatchFinder::MatchResult &Result) {
129  const auto *Definition = Result.Nodes.getNodeAs<CXXMethodDecl>("x");
130 
131  // TODO: For out-of-line declarations, don't modify the source if the header
132  // is excluded by the -header-filter option.
133  DiagnosticBuilder Diag =
134  diag(Definition->getLocation(), "method %0 can be made static")
135  << Definition;
136 
137  // TODO: Would need to remove those in a fix-it.
138  if (Definition->getMethodQualifiers().hasVolatile() ||
139  Definition->getMethodQualifiers().hasRestrict() ||
140  Definition->getRefQualifier() != RQ_None)
141  return;
142 
143  const CXXMethodDecl *Declaration = Definition->getCanonicalDecl();
144 
145  if (Definition->isConst()) {
146  // Make sure that we either remove 'const' on both declaration and
147  // definition or emit no fix-it at all.
148  SourceRange DefConst = getLocationOfConst(Definition->getTypeSourceInfo(),
149  *Result.SourceManager,
150  Result.Context->getLangOpts());
151 
152  if (DefConst.isInvalid())
153  return;
154 
155  if (Declaration != Definition) {
156  SourceRange DeclConst = getLocationOfConst(
157  Declaration->getTypeSourceInfo(), *Result.SourceManager,
158  Result.Context->getLangOpts());
159 
160  if (DeclConst.isInvalid())
161  return;
162  Diag << FixItHint::CreateRemoval(DeclConst);
163  }
164 
165  // Remove existing 'const' from both declaration and definition.
166  Diag << FixItHint::CreateRemoval(DefConst);
167  }
168  Diag << FixItHint::CreateInsertion(Declaration->getBeginLoc(), "static ");
169 }
170 
171 } // namespace readability
172 } // namespace tidy
173 } // namespace clang
std::string Text
static StringRef getStringFromRange(SourceManager &SourceMgr, const LangOptions &LangOpts, SourceRange Range)
Obtain the original source code text from a SourceRange.
static SourceRange getLocationOfConst(const TypeSourceInfo *TSI, SourceManager &SourceMgr, const LangOptions &LangOpts)
llvm::SourceMgr * SourceMgr
CodeCompletionBuilder Builder
size_t Offset
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
CharSourceRange Range
SourceRange for the file name.
const Expr * E
AST_MATCHER_P(CXXMethodDecl, hasCanonicalDecl, ast_matchers::internal::Matcher< CXXMethodDecl >, InnerMatcher)