1 //===--- NoexceptMoveConstructorCheck.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 "NoexceptMoveConstructorCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/Lex/Lexer.h"
13 #include "clang/Tooling/FixIt.h"
14
15 using namespace clang::ast_matchers;
16
17 namespace clang {
18 namespace tidy {
19 namespace performance {
20
registerMatchers(MatchFinder * Finder)21 void NoexceptMoveConstructorCheck::registerMatchers(MatchFinder *Finder) {
22 Finder->addMatcher(
23 cxxMethodDecl(anyOf(cxxConstructorDecl(), hasOverloadedOperatorName("=")),
24 unless(isImplicit()), unless(isDeleted()))
25 .bind("decl"),
26 this);
27 }
28
check(const MatchFinder::MatchResult & Result)29 void NoexceptMoveConstructorCheck::check(
30 const MatchFinder::MatchResult &Result) {
31 if (const auto *Decl = Result.Nodes.getNodeAs<CXXMethodDecl>("decl")) {
32 bool IsConstructor = false;
33 if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(Decl)) {
34 if (!Ctor->isMoveConstructor())
35 return;
36 IsConstructor = true;
37 } else if (!Decl->isMoveAssignmentOperator()) {
38 return;
39 }
40
41 const auto *ProtoType = Decl->getType()->castAs<FunctionProtoType>();
42
43 if (isUnresolvedExceptionSpec(ProtoType->getExceptionSpecType()))
44 return;
45
46 if (!isNoexceptExceptionSpec(ProtoType->getExceptionSpecType())) {
47 auto Diag = diag(Decl->getLocation(),
48 "move %select{assignment operator|constructor}0s should "
49 "be marked noexcept")
50 << IsConstructor;
51 // Add FixIt hints.
52 SourceManager &SM = *Result.SourceManager;
53 assert(Decl->getNumParams() > 0);
54 SourceLocation NoexceptLoc = Decl->getParamDecl(Decl->getNumParams() - 1)
55 ->getSourceRange()
56 .getEnd();
57 if (NoexceptLoc.isValid())
58 NoexceptLoc = Lexer::findLocationAfterToken(
59 NoexceptLoc, tok::r_paren, SM, Result.Context->getLangOpts(), true);
60 if (NoexceptLoc.isValid())
61 Diag << FixItHint::CreateInsertion(NoexceptLoc, " noexcept ");
62 return;
63 }
64
65 // Don't complain about nothrow(false), but complain on nothrow(expr)
66 // where expr evaluates to false.
67 if (ProtoType->canThrow() == CT_Can) {
68 Expr *E = ProtoType->getNoexceptExpr();
69 E = E->IgnoreImplicit();
70 if (!isa<CXXBoolLiteralExpr>(E)) {
71 diag(E->getExprLoc(),
72 "noexcept specifier on the move %select{assignment "
73 "operator|constructor}0 evaluates to 'false'")
74 << IsConstructor;
75 }
76 }
77 }
78 }
79
80 } // namespace performance
81 } // namespace tidy
82 } // namespace clang
83