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
9#include "ProBoundsArrayToPointerDecayCheck.h"
10#include "clang/AST/ASTContext.h"
11#include "clang/AST/ParentMapContext.h"
12#include "clang/ASTMatchers/ASTMatchFinder.h"
13#include "clang/ASTMatchers/ASTMatchers.h"
14
15using namespace clang::ast_matchers;
16
17namespace clang::tidy::cppcoreguidelines {
18
19namespace {
20AST_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(Node: *Stmt, Finder, Builder))
24 return true;
25 return false;
26}
27
28AST_MATCHER(Stmt, isInsideOfRangeBeginEndStmt) {
29 return stmt(hasAncestor(cxxForRangeStmt(
30 hasRangeBeginEndStmt(InnerMatcher: hasDescendant(equalsNode(Other: &Node))))))
31 .matches(Node, Finder, Builder);
32}
33
34AST_MATCHER_P(Expr, hasParentIgnoringImpCasts,
35 ast_matchers::internal::Matcher<Expr>, InnerMatcher) {
36 const Expr *E = &Node;
37 do {
38 DynTypedNodeList Parents = Finder->getASTContext().getParents(Node: *E);
39 if (Parents.size() != 1)
40 return false;
41 E = Parents[0].get<Expr>();
42 if (!E)
43 return false;
44 } while (isa<ImplicitCastExpr>(Val: E));
45
46 return InnerMatcher.matches(Node: *E, Finder, Builder);
47}
48} // namespace
49
50void ProBoundsArrayToPointerDecayCheck::registerMatchers(MatchFinder *Finder) {
51 // The only allowed array to pointer decay
52 // 1) just before array subscription
53 // 2) inside a range-for over an array
54 // 3) if it converts a string literal to a pointer
55 Finder->addMatcher(
56 NodeMatch: traverse(
57 TK: TK_AsIs,
58 InnerMatcher: implicitCastExpr(
59 unless(hasParent(arraySubscriptExpr())),
60 unless(hasSourceExpression(InnerMatcher: predefinedExpr())),
61 unless(hasParentIgnoringImpCasts(InnerMatcher: explicitCastExpr())),
62 unless(isInsideOfRangeBeginEndStmt()),
63 unless(hasSourceExpression(InnerMatcher: ignoringParens(InnerMatcher: stringLiteral()))),
64 unless(hasSourceExpression(InnerMatcher: ignoringParens(
65 InnerMatcher: conditionalOperator(hasTrueExpression(InnerMatcher: stringLiteral()),
66 hasFalseExpression(InnerMatcher: stringLiteral()))))))
67 .bind(ID: "cast")),
68 Action: this);
69}
70
71void ProBoundsArrayToPointerDecayCheck::check(
72 const MatchFinder::MatchResult &Result) {
73 const auto *MatchedCast = Result.Nodes.getNodeAs<ImplicitCastExpr>(ID: "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 clang::tidy::cppcoreguidelines
83

source code of clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsArrayToPointerDecayCheck.cpp