clang-tools  10.0.0svn
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 
17 using namespace clang::ast_matchers;
18 
19 namespace clang {
20 namespace tidy {
21 namespace readability {
22 
23 AST_MATCHER(CXXMethodDecl, isStatic) { return Node.isStatic(); }
24 
25 AST_MATCHER(CXXMethodDecl, hasTrivialBody) { return Node.hasTrivialBody(); }
26 
27 AST_MATCHER(CXXMethodDecl, isOverloadedOperator) {
28  return Node.isOverloadedOperator();
29 }
30 
31 AST_MATCHER(CXXRecordDecl, hasAnyDependentBases) {
32  return Node.hasAnyDependentBases();
33 }
34 
35 AST_MATCHER(CXXMethodDecl, isTemplate) {
36  return Node.getTemplatedKind() != FunctionDecl::TK_NonTemplate;
37 }
38 
39 AST_MATCHER(CXXMethodDecl, isDependentContext) {
40  return Node.isDependentContext();
41 }
42 
43 AST_MATCHER(CXXMethodDecl, isInsideMacroDefinition) {
44  const ASTContext &Ctxt = Finder->getASTContext();
45  return clang::Lexer::makeFileCharRange(
46  clang::CharSourceRange::getCharRange(
47  Node.getTypeSourceInfo()->getTypeLoc().getSourceRange()),
48  Ctxt.getSourceManager(), Ctxt.getLangOpts())
49  .isInvalid();
50 }
51 
52 AST_MATCHER_P(CXXMethodDecl, hasCanonicalDecl,
53  ast_matchers::internal::Matcher<CXXMethodDecl>, InnerMatcher) {
54  return InnerMatcher.matches(*Node.getCanonicalDecl(), Finder, Builder);
55 }
56 
57 AST_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  } UsageOfThis;
67 
68  // TraverseStmt does not modify its argument.
69  UsageOfThis.TraverseStmt(const_cast<Stmt *>(Node.getBody()));
70 
71  return UsageOfThis.Used;
72 }
73 
74 void ConvertMemberFunctionsToStatic::registerMatchers(MatchFinder *Finder) {
75  Finder->addMatcher(
76  cxxMethodDecl(
77  isDefinition(), isUserProvided(),
78  unless(anyOf(
79  isExpansionInSystemHeader(), isVirtual(), isStatic(),
80  hasTrivialBody(), isOverloadedOperator(), cxxConstructorDecl(),
81  cxxDestructorDecl(), cxxConversionDecl(), isTemplate(),
82  isDependentContext(),
83  ofClass(anyOf(
84  isLambda(),
85  hasAnyDependentBases()) // Method might become virtual
86  // depending on template base class.
87  ),
88  isInsideMacroDefinition(),
89  hasCanonicalDecl(isInsideMacroDefinition()), usesThis())))
90  .bind("x"),
91  this);
92 }
93 
94 /// Obtain the original source code text from a SourceRange.
95 static StringRef getStringFromRange(SourceManager &SourceMgr,
96  const LangOptions &LangOpts,
97  SourceRange Range) {
98  if (SourceMgr.getFileID(Range.getBegin()) !=
99  SourceMgr.getFileID(Range.getEnd()))
100  return {};
101 
102  return Lexer::getSourceText(CharSourceRange(Range, true), SourceMgr,
103  LangOpts);
104 }
105 
106 static SourceRange getLocationOfConst(const TypeSourceInfo *TSI,
107  SourceManager &SourceMgr,
108  const LangOptions &LangOpts) {
109  assert(TSI);
110  const auto FTL = TSI->getTypeLoc().IgnoreParens().getAs<FunctionTypeLoc>();
111  assert(FTL);
112 
113  SourceRange Range{FTL.getRParenLoc().getLocWithOffset(1),
114  FTL.getLocalRangeEnd()};
115  // Inside Range, there might be other keywords and trailing return types.
116  // Find the exact position of "const".
117  StringRef Text = getStringFromRange(SourceMgr, LangOpts, Range);
118  size_t Offset = Text.find("const");
119  if (Offset == StringRef::npos)
120  return {};
121 
122  SourceLocation Start = Range.getBegin().getLocWithOffset(Offset);
123  return {Start, Start.getLocWithOffset(strlen("const") - 1)};
124 }
125 
126 void ConvertMemberFunctionsToStatic::check(
127  const MatchFinder::MatchResult &Result) {
128  const auto *Definition = Result.Nodes.getNodeAs<CXXMethodDecl>("x");
129 
130  // TODO: For out-of-line declarations, don't modify the source if the header
131  // is excluded by the -header-filter option.
132  DiagnosticBuilder Diag =
133  diag(Definition->getLocation(), "method %0 can be made static")
134  << Definition;
135 
136  // TODO: Would need to remove those in a fix-it.
137  if (Definition->getMethodQualifiers().hasVolatile() ||
138  Definition->getMethodQualifiers().hasRestrict() ||
139  Definition->getRefQualifier() != RQ_None)
140  return;
141 
142  const CXXMethodDecl *Declaration = Definition->getCanonicalDecl();
143 
144  if (Definition->isConst()) {
145  // Make sure that we either remove 'const' on both declaration and
146  // definition or emit no fix-it at all.
147  SourceRange DefConst = getLocationOfConst(Definition->getTypeSourceInfo(),
148  *Result.SourceManager,
149  Result.Context->getLangOpts());
150 
151  if (DefConst.isInvalid())
152  return;
153 
154  if (Declaration != Definition) {
155  SourceRange DeclConst = getLocationOfConst(
156  Declaration->getTypeSourceInfo(), *Result.SourceManager,
157  Result.Context->getLangOpts());
158 
159  if (DeclConst.isInvalid())
160  return;
161  Diag << FixItHint::CreateRemoval(DeclConst);
162  }
163 
164  // Remove existing 'const' from both declaration and definition.
165  Diag << FixItHint::CreateRemoval(DefConst);
166  }
167  Diag << FixItHint::CreateInsertion(Declaration->getBeginLoc(), "static ");
168 }
169 
170 } // namespace readability
171 } // namespace tidy
172 } // 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)
CodeCompletionBuilder Builder
size_t Offset
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
CharSourceRange Range
SourceRange for the file name.
AST_MATCHER_P(CXXMethodDecl, hasCanonicalDecl, ast_matchers::internal::Matcher< CXXMethodDecl >, InnerMatcher)