clang-tools-extra/clang-tidy/modernize/UseEqualsDeleteCheck.cpp

   1 //===--- UseEqualsDeleteCheck.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 "UseEqualsDeleteCheck.h"
  10 #include "clang/AST/ASTContext.h"
  11 #include "clang/ASTMatchers/ASTMatchFinder.h"
  12 #include "clang/Lex/Lexer.h"
  13
  14 using namespace clang::ast_matchers;
  15
  16 namespace clang::tidy::modernize {
  17
  18 namespace {
  19 AST_MATCHER(FunctionDecl, hasAnyDefinition) {
  20   if (Node.hasBody() || Node.isPureVirtual() || Node.isDefaulted() ||
  21       Node.isDeleted())
  22     return true;
  23
  24   if (const FunctionDecl *Definition = Node.getDefinition())
  25     if (Definition->hasBody() || Definition->isPureVirtual() ||
  26         Definition->isDefaulted() || Definition->isDeleted())
  27       return true;
  28
  29   return false;
  30 }
  31
  32 AST_MATCHER(Decl, isUsed) { return Node.isUsed(); }
  33
  34 AST_MATCHER(CXXMethodDecl, isSpecialFunction) {
  35   if (const auto *Constructor = dyn_cast<CXXConstructorDecl>(&Node))
  36     return Constructor->isDefaultConstructor() ||
  37            Constructor->isCopyOrMoveConstructor();
  38
  39   return isa<CXXDestructorDecl>(Node) || Node.isCopyAssignmentOperator() ||
  40          Node.isMoveAssignmentOperator();
  41 }
  42 } // namespace
  43
  44 static const char SpecialFunction[] = "SpecialFunction";
  45 static const char DeletedNotPublic[] = "DeletedNotPublic";
  46
  47 UseEqualsDeleteCheck::UseEqualsDeleteCheck(StringRef Name,
  48                                            ClangTidyContext *Context)
  49     : ClangTidyCheck(Name, Context),
  50       IgnoreMacros(Options.getLocalOrGlobal("IgnoreMacros", true)) {}
  51
  52 void UseEqualsDeleteCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
  53   Options.store(Opts, "IgnoreMacros", IgnoreMacros);
  54 }
  55
  56 void UseEqualsDeleteCheck::registerMatchers(MatchFinder *Finder) {
  57   auto PrivateSpecialFn = cxxMethodDecl(isPrivate(), isSpecialFunction());
  58
  59   Finder->addMatcher(
  60       cxxMethodDecl(
  61           PrivateSpecialFn, unless(hasAnyDefinition()), unless(isUsed()),
  62           // Ensure that all methods except private special member functions are
  63           // defined.
  64           unless(ofClass(hasMethod(cxxMethodDecl(unless(PrivateSpecialFn),
  65                                                  unless(hasAnyDefinition()))))))
  66           .bind(SpecialFunction),
  67       this);
  68
  69   Finder->addMatcher(
  70       cxxMethodDecl(isDeleted(), unless(isPublic())).bind(DeletedNotPublic),
  71       this);
  72 }
  73
  74 void UseEqualsDeleteCheck::check(const MatchFinder::MatchResult &Result) {
  75   if (const auto *Func =
  76           Result.Nodes.getNodeAs<CXXMethodDecl>(SpecialFunction)) {
  77     SourceLocation EndLoc = Lexer::getLocForEndOfToken(
  78         Func->getEndLoc(), 0, *Result.SourceManager, getLangOpts());
  79
  80     if (IgnoreMacros && Func->getLocation().isMacroID())
  81       return;
  82     // FIXME: Improve FixItHint to make the method public.
  83     diag(Func->getLocation(),
  84          "use '= delete' to prohibit calling of a special member function")
  85         << FixItHint::CreateInsertion(EndLoc, " = delete");
  86   } else if (const auto *Func =
  87                  Result.Nodes.getNodeAs<CXXMethodDecl>(DeletedNotPublic)) {
  88     // Ignore this warning in macros, since it's extremely noisy in code using
  89     // DISALLOW_COPY_AND_ASSIGN-style macros and there's no easy way to
  90     // automatically fix the warning when macros are in play.
  91     if (IgnoreMacros && Func->getLocation().isMacroID())
  92       return;
  93     // FIXME: Add FixItHint to make the method public.
  94     diag(Func->getLocation(), "deleted member function should be public");
  95   }
  96 }
  97
  98 } // namespace clang::tidy::modernize