clang-tools  7.0.0
ProBoundsArrayToPointerDecayCheck.cpp
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1 //===--- ProBoundsArrayToPointerDecayCheck.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 
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 
14 using namespace clang::ast_matchers;
15 
16 namespace clang {
17 namespace tidy {
18 namespace cppcoreguidelines {
19 
20 namespace {
21 AST_MATCHER_P(CXXForRangeStmt, hasRangeBeginEndStmt,
22  ast_matchers::internal::Matcher<DeclStmt>, InnerMatcher) {
23  for (const DeclStmt *Stmt : {Node.getBeginStmt(), Node.getEndStmt()})
24  if (Stmt != nullptr && InnerMatcher.matches(*Stmt, Finder, Builder))
25  return true;
26  return false;
27 }
28 
29 AST_MATCHER(Stmt, isInsideOfRangeBeginEndStmt) {
30  return stmt(hasAncestor(cxxForRangeStmt(
31  hasRangeBeginEndStmt(hasDescendant(equalsNode(&Node))))))
32  .matches(Node, Finder, Builder);
33 }
34 
35 AST_MATCHER_P(Expr, hasParentIgnoringImpCasts,
36  ast_matchers::internal::Matcher<Expr>, InnerMatcher) {
37  const Expr *E = &Node;
38  do {
39  ASTContext::DynTypedNodeList Parents =
40  Finder->getASTContext().getParents(*E);
41  if (Parents.size() != 1)
42  return false;
43  E = Parents[0].get<Expr>();
44  if (!E)
45  return false;
46  } while (isa<ImplicitCastExpr>(E));
47 
48  return InnerMatcher.matches(*E, Finder, Builder);
49 }
50 } // namespace
51 
52 void ProBoundsArrayToPointerDecayCheck::registerMatchers(MatchFinder *Finder) {
53  if (!getLangOpts().CPlusPlus)
54  return;
55 
56  // The only allowed array to pointer decay
57  // 1) just before array subscription
58  // 2) inside a range-for over an array
59  // 3) if it converts a string literal to a pointer
60  Finder->addMatcher(
61  implicitCastExpr(unless(hasParent(arraySubscriptExpr())),
62  unless(hasParentIgnoringImpCasts(explicitCastExpr())),
63  unless(isInsideOfRangeBeginEndStmt()),
64  unless(hasSourceExpression(stringLiteral())))
65  .bind("cast"),
66  this);
67 }
68 
69 void ProBoundsArrayToPointerDecayCheck::check(
70  const MatchFinder::MatchResult &Result) {
71  const auto *MatchedCast = Result.Nodes.getNodeAs<ImplicitCastExpr>("cast");
72  if (MatchedCast->getCastKind() != CK_ArrayToPointerDecay)
73  return;
74 
75  diag(MatchedCast->getExprLoc(), "do not implicitly decay an array into a "
76  "pointer; consider using gsl::array_view or "
77  "an explicit cast instead");
78 }
79 
80 } // namespace cppcoreguidelines
81 } // namespace tidy
82 } // namespace clang
AST_MATCHER(BinaryOperator, isAssignmentOperator)
Definition: Matchers.h:20
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
AST_MATCHER_P(FunctionDecl, throws, internal::Matcher< Type >, InnerMatcher)