clang-tools 6.0.0

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
10 #include "ProBoundsArrayToPointerDecayCheck.h"
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 AST_MATCHER_P(CXXForRangeStmt, hasRangeBeginEndStmt,
21 ast_matchers::internal::Matcher<DeclStmt>, InnerMatcher) {
22 for (const DeclStmt *Stmt : {Node.getBeginStmt(), Node.getEndStmt()})
23 if (Stmt != nullptr && InnerMatcher.matches(*Stmt, Finder, Builder))
24 return true;
25 return false;
26 }
27
28 AST_MATCHER(Stmt, isInsideOfRangeBeginEndStmt) {
29 return stmt(hasAncestor(cxxForRangeStmt(
30 hasRangeBeginEndStmt(hasDescendant(equalsNode(&Node))))))
31 .matches(Node, Finder, Builder);
32 }
33
34 AST_MATCHER_P(Expr, hasParentIgnoringImpCasts,
35 ast_matchers::internal::Matcher<Expr>, InnerMatcher) {
36 const Expr *E = &Node;
37 do {
38 ASTContext::DynTypedNodeList Parents =
39 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
50 void ProBoundsArrayToPointerDecayCheck::registerMatchers(MatchFinder *Finder) {
51 if (!getLangOpts().CPlusPlus)
52 return;
53
54 // The only allowed array to pointer decay
55 // 1) just before array subscription
56 // 2) inside a range-for over an array
57 // 3) if it converts a string literal to a pointer
58 Finder->addMatcher(
59 implicitCastExpr(unless(hasParent(arraySubscriptExpr())),
60 unless(hasParentIgnoringImpCasts(explicitCastExpr())),
61 unless(isInsideOfRangeBeginEndStmt()),
62 unless(hasSourceExpression(stringLiteral())))
63 .bind("cast"),
64 this);
65 }
66
67 void ProBoundsArrayToPointerDecayCheck::check(
68 const MatchFinder::MatchResult &Result) {
69 const auto *MatchedCast = Result.Nodes.getNodeAs<ImplicitCastExpr>("cast");
70 if (MatchedCast->getCastKind() != CK_ArrayToPointerDecay)
71 return;
72
73 diag(MatchedCast->getExprLoc(), "do not implicitly decay an array into a "
74 "pointer; consider using gsl::array_view or "
75 "an explicit cast instead");
76 }
77
78 } // namespace cppcoreguidelines
79 } // namespace tidy
80 } // namespace clang
clang::ast_matchers
Definition: ClangTidyDiagnosticConsumer.h:27
clang::tidy::cppcoreguidelines::AST_MATCHER_P
AST_MATCHER_P(Expr, hasParentIgnoringImpCasts, ast_matchers::internal::Matcher< Expr >, InnerMatcher)
Definition: ProBoundsArrayToPointerDecayCheck.cpp:34
ProBoundsArrayToPointerDecayCheck.h
clang
Definition: AndroidTidyModule.cpp:28
clang::ast_matchers::AST_MATCHER
AST_MATCHER(VarDecl, isAsm)
Definition: NoAssemblerCheck.cpp:18