1 //===--- NonCopyableObjects.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 "NonCopyableObjects.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include <algorithm>
13
14 using namespace clang::ast_matchers;
15
16 namespace clang::tidy::misc {
17
registerMatchers(MatchFinder * Finder)18 void NonCopyableObjectsCheck::registerMatchers(MatchFinder *Finder) {
19 // There are two ways to get into trouble with objects like FILE *:
20 // dereferencing the pointer type to be a non-pointer type, and declaring
21 // the type as a non-pointer type in the first place. While the declaration
22 // itself could technically be well-formed in the case where the type is not
23 // an opaque type, it's highly suspicious behavior.
24 //
25 // POSIX types are a bit different in that it's reasonable to declare a
26 // non-pointer variable or data member of the type, but it is not reasonable
27 // to dereference a pointer to the type, or declare a parameter of non-pointer
28 // type.
29 // FIXME: it would be good to make a list that is also user-configurable so
30 // that users can add their own elements to the list. However, it may require
31 // some extra thought since POSIX types and FILE types are usable in different
32 // ways.
33
34 auto BadFILEType = hasType(
35 namedDecl(hasAnyName("::FILE", "FILE", "std::FILE")).bind("type_decl"));
36 auto BadPOSIXType =
37 hasType(namedDecl(hasAnyName("::pthread_cond_t", "::pthread_mutex_t",
38 "pthread_cond_t", "pthread_mutex_t"))
39 .bind("type_decl"));
40 auto BadEitherType = anyOf(BadFILEType, BadPOSIXType);
41
42 Finder->addMatcher(
43 namedDecl(anyOf(varDecl(BadFILEType), fieldDecl(BadFILEType)))
44 .bind("decl"),
45 this);
46 Finder->addMatcher(parmVarDecl(BadPOSIXType).bind("decl"), this);
47 Finder->addMatcher(
48 expr(unaryOperator(hasOperatorName("*"), BadEitherType)).bind("expr"),
49 this);
50 }
51
check(const MatchFinder::MatchResult & Result)52 void NonCopyableObjectsCheck::check(const MatchFinder::MatchResult &Result) {
53 const auto *D = Result.Nodes.getNodeAs<NamedDecl>("decl");
54 const auto *BD = Result.Nodes.getNodeAs<NamedDecl>("type_decl");
55 const auto *E = Result.Nodes.getNodeAs<Expr>("expr");
56
57 if (D && BD)
58 diag(D->getLocation(), "%0 declared as type '%1', which is unsafe to copy"
59 "; did you mean '%1 *'?")
60 << D << BD->getName();
61 else if (E)
62 diag(E->getExprLoc(),
63 "expression has opaque data structure type %0; type should only be "
64 "used as a pointer and not dereferenced")
65 << BD;
66 }
67
68 } // namespace clang::tidy::misc
69