clang-tools  16.0.0git
ProBoundsArrayToPointerDecayCheck.cpp
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1 //===--- ProBoundsArrayToPointerDecayCheck.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 
10 #include "clang/AST/ASTContext.h"
11 #include "clang/AST/ParentMapContext.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  DynTypedNodeList Parents = Finder->getASTContext().getParents(*E);
40  if (Parents.size() != 1)
41  return false;
42  E = Parents[0].get<Expr>();
43  if (!E)
44  return false;
45  } while (isa<ImplicitCastExpr>(E));
46 
47  return InnerMatcher.matches(*E, Finder, Builder);
48 }
49 } // namespace
50 
51 void ProBoundsArrayToPointerDecayCheck::registerMatchers(MatchFinder *Finder) {
52  // The only allowed array to pointer decay
53  // 1) just before array subscription
54  // 2) inside a range-for over an array
55  // 3) if it converts a string literal to a pointer
56  Finder->addMatcher(
57  traverse(
58  TK_AsIs,
59  implicitCastExpr(
60  unless(hasParent(arraySubscriptExpr())),
61  unless(hasParentIgnoringImpCasts(explicitCastExpr())),
62  unless(isInsideOfRangeBeginEndStmt()),
63  unless(hasSourceExpression(ignoringParens(stringLiteral()))),
64  unless(hasSourceExpression(ignoringParens(conditionalOperator(
65  allOf(hasTrueExpression(stringLiteral()),
66  hasFalseExpression(stringLiteral())))))))
67  .bind("cast")),
68  this);
69 }
70 
72  const MatchFinder::MatchResult &Result) {
73  const auto *MatchedCast = Result.Nodes.getNodeAs<ImplicitCastExpr>("cast");
74  if (MatchedCast->getCastKind() != CK_ArrayToPointerDecay)
75  return;
76 
77  diag(MatchedCast->getExprLoc(), "do not implicitly decay an array into a "
78  "pointer; consider using gsl::array_view or "
79  "an explicit cast instead");
80 }
81 
82 } // namespace cppcoreguidelines
83 } // namespace tidy
84 } // namespace clang
E
const Expr * E
Definition: AvoidBindCheck.cpp:88
clang::clangd::TypeHierarchyDirection::Parents
@ Parents
clang::ast_matchers
Definition: AbseilMatcher.h:14
ProBoundsArrayToPointerDecayCheck.h
clang::ast_matchers::AST_MATCHER
AST_MATCHER(Decl, declHasNoReturnAttr)
matches a Decl if it has a "no return" attribute of any kind
Definition: InfiniteLoopCheck.cpp:24
Builder
CodeCompletionBuilder Builder
Definition: CodeCompletionStringsTests.cpp:36
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
clang::clangd::check
bool check(llvm::StringRef File, const ThreadsafeFS &TFS, const ClangdLSPServer::Options &Opts)
Definition: Check.cpp:415
clang::tidy::bugprone::AST_MATCHER_P
AST_MATCHER_P(FunctionDecl, parameterCountGE, unsigned, N)
Matches functions that have at least the specified amount of parameters.
Definition: EasilySwappableParametersCheck.cpp:1886