clang-tools-extra/clang-tidy/performance/NoexceptSwapCheck.cpp

   1 //===--- NoexceptSwapCheck.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 "NoexceptSwapCheck.h"
  10 #include "clang/ASTMatchers/ASTMatchFinder.h"
  11
  12 using namespace clang::ast_matchers;
  13
  14 // FixItHint - comment added to fix list.rst generation in add_new_check.py.
  15 // Do not remove. Fixes are generated in base class.
  16
  17 namespace clang::tidy::performance {
  18
  19 void NoexceptSwapCheck::registerMatchers(MatchFinder *Finder) {
  20
  21   // Match non-const method with single argument that is non-const reference to
  22   // a class type that owns method and return void.
  23   // Matches: void Class::swap(Class&)
  24   auto MethodMatcher = cxxMethodDecl(
  25       parameterCountIs(1U), unless(isConst()), returns(voidType()),
  26       hasParameter(0, hasType(qualType(hasCanonicalType(
  27                           qualType(unless(isConstQualified()),
  28                                    references(namedDecl().bind("class"))))))),
  29       ofClass(equalsBoundNode("class")));
  30
  31   // Match function with 2 arguments, both are non-const references to same type
  32   // and return void.
  33   // Matches: void swap(Type&, Type&)
  34   auto FunctionMatcher = allOf(
  35       unless(cxxMethodDecl()), parameterCountIs(2U), returns(voidType()),
  36       hasParameter(
  37           0, hasType(qualType(hasCanonicalType(
  38                  qualType(unless(isConstQualified()), references(qualType()))
  39                      .bind("type"))))),
  40       hasParameter(1, hasType(qualType(hasCanonicalType(
  41                           qualType(equalsBoundNode("type")))))));
  42   Finder->addMatcher(functionDecl(unless(isDeleted()),
  43                                   hasAnyName("swap", "iter_swap"),
  44                                   anyOf(MethodMatcher, FunctionMatcher))
  45                          .bind(BindFuncDeclName),
  46                      this);
  47 }
  48
  49 DiagnosticBuilder
  50 NoexceptSwapCheck::reportMissingNoexcept(const FunctionDecl *FuncDecl) {
  51   return diag(FuncDecl->getLocation(), "swap functions should "
  52                                        "be marked noexcept");
  53 }
  54
  55 void NoexceptSwapCheck::reportNoexceptEvaluatedToFalse(
  56     const FunctionDecl *FuncDecl, const Expr *NoexceptExpr) {
  57   diag(NoexceptExpr->getExprLoc(),
  58        "noexcept specifier on swap function evaluates to 'false'");
  59 }
  60
  61 } // namespace clang::tidy::performance