clang-tools  6.0.0
NonCopyableObjects.cpp
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1 //===--- NonCopyableObjects.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 "NonCopyableObjects.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include <algorithm>
14 
15 using namespace clang::ast_matchers;
16 
17 namespace clang {
18 namespace tidy {
19 namespace misc {
20 
21 void NonCopyableObjectsCheck::registerMatchers(MatchFinder *Finder) {
22  // There are two ways to get into trouble with objects like FILE *:
23  // dereferencing the pointer type to be a non-pointer type, and declaring
24  // the type as a non-pointer type in the first place. While the declaration
25  // itself could technically be well-formed in the case where the type is not
26  // an opaque type, it's highly suspicious behavior.
27  //
28  // POSIX types are a bit different in that it's reasonable to declare a
29  // non-pointer variable or data member of the type, but it is not reasonable
30  // to dereference a pointer to the type, or declare a parameter of non-pointer
31  // type.
32  // FIXME: it would be good to make a list that is also user-configurable so
33  // that users can add their own elements to the list. However, it may require
34  // some extra thought since POSIX types and FILE types are usable in different
35  // ways.
36 
37  auto BadFILEType = hasType(
38  namedDecl(hasAnyName("::FILE", "FILE", "std::FILE")).bind("type_decl"));
39  auto BadPOSIXType =
40  hasType(namedDecl(hasAnyName("::pthread_cond_t", "::pthread_mutex_t",
41  "pthread_cond_t", "pthread_mutex_t"))
42  .bind("type_decl"));
43  auto BadEitherType = anyOf(BadFILEType, BadPOSIXType);
44 
45  Finder->addMatcher(
46  namedDecl(anyOf(varDecl(BadFILEType), fieldDecl(BadFILEType)))
47  .bind("decl"),
48  this);
49  Finder->addMatcher(parmVarDecl(BadPOSIXType).bind("decl"), this);
50  Finder->addMatcher(
51  expr(unaryOperator(hasOperatorName("*"), BadEitherType)).bind("expr"),
52  this);
53 }
54 
55 void NonCopyableObjectsCheck::check(const MatchFinder::MatchResult &Result) {
56  const auto *D = Result.Nodes.getNodeAs<NamedDecl>("decl");
57  const auto *BD = Result.Nodes.getNodeAs<NamedDecl>("type_decl");
58  const auto *E = Result.Nodes.getNodeAs<Expr>("expr");
59 
60  if (D && BD)
61  diag(D->getLocation(), "%0 declared as type '%1', which is unsafe to copy"
62  "; did you mean '%1 *'?")
63  << D << BD->getName();
64  else if (E)
65  diag(E->getExprLoc(),
66  "expression has opaque data structure type %0; type should only be "
67  "used as a pointer and not dereferenced")
68  << BD;
69 }
70 
71 } // namespace misc
72 } // namespace tidy
73 } // namespace clang
74