1 //===--- UniqueptrDeleteReleaseCheck.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 
10 #include "UniqueptrDeleteReleaseCheck.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/Lex/Lexer.h"
14 
15 using namespace clang::ast_matchers;
16 
17 namespace clang {
18 namespace tidy {
19 namespace readability {
20 
21 void UniqueptrDeleteReleaseCheck::registerMatchers(MatchFinder *Finder) {
22   auto IsSusbstituted = qualType(anyOf(
23       substTemplateTypeParmType(), hasDescendant(substTemplateTypeParmType())));
24 
25   auto UniquePtrWithDefaultDelete = classTemplateSpecializationDecl(
26       hasName("std::unique_ptr"),
27       hasTemplateArgument(1, refersToType(qualType(hasDeclaration(cxxRecordDecl(
28                                  hasName("std::default_delete")))))));
29 
30   Finder->addMatcher(
31       cxxDeleteExpr(has(ignoringParenImpCasts(cxxMemberCallExpr(
32                         on(expr(hasType(UniquePtrWithDefaultDelete),
33                                 unless(hasType(IsSusbstituted)))
34                                .bind("uptr")),
35                         callee(cxxMethodDecl(hasName("release")))))))
36           .bind("delete"),
37       this);
38 }
39 
40 void UniqueptrDeleteReleaseCheck::check(
41     const MatchFinder::MatchResult &Result) {
42   const auto *PtrExpr = Result.Nodes.getNodeAs<Expr>("uptr");
43   const auto *DeleteExpr = Result.Nodes.getNodeAs<Expr>("delete");
44 
45   if (PtrExpr->getLocStart().isMacroID())
46     return;
47 
48   // Ignore dependent types.
49   // It can give us false positives, so we go with false negatives instead to
50   // be safe.
51   if (PtrExpr->getType()->isDependentType())
52     return;
53 
54   SourceLocation AfterPtr = Lexer::getLocForEndOfToken(
55       PtrExpr->getLocEnd(), 0, *Result.SourceManager, getLangOpts());
56 
57   diag(DeleteExpr->getLocStart(),
58        "prefer '= nullptr' to 'delete x.release()' to reset unique_ptr<> "
59        "objects")
60       << FixItHint::CreateRemoval(CharSourceRange::getCharRange(
61              DeleteExpr->getLocStart(), PtrExpr->getLocStart()))
62       << FixItHint::CreateReplacement(
63              CharSourceRange::getTokenRange(AfterPtr, DeleteExpr->getLocEnd()),
64              " = nullptr");
65 }
66 
67 } // namespace readability
68 } // namespace tidy
69 } // namespace clang
70