clang-tools 20.0.0git
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#include "clang/ASTMatchers/ASTMatchers.h"
14
15using namespace clang::ast_matchers;
16
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(*Stmt, Finder, Builder))
24 return true;
25 return false;
26}
27
28AST_MATCHER(Stmt, isInsideOfRangeBeginEndStmt) {
29 return stmt(hasAncestor(cxxForRangeStmt(
30 hasRangeBeginEndStmt(hasDescendant(equalsNode(&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(*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>(E));
45
46 return InnerMatcher.matches(*E, Finder, Builder);
47}
48} // namespace
49
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 traverse(
57 TK_AsIs,
58 implicitCastExpr(
59 unless(hasParent(arraySubscriptExpr())),
60 unless(hasSourceExpression(predefinedExpr())),
61 unless(hasParentIgnoringImpCasts(explicitCastExpr())),
62 unless(isInsideOfRangeBeginEndStmt()),
63 unless(hasSourceExpression(ignoringParens(stringLiteral()))),
64 unless(hasSourceExpression(ignoringParens(
65 conditionalOperator(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 clang::tidy::cppcoreguidelines
const Expr * E
CodeCompletionBuilder Builder
::clang::DynTypedNode Node
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check's name.
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
AST_MATCHER_P(UserDefinedLiteral, hasLiteral, clang::ast_matchers::internal::Matcher< Expr >, InnerMatcher)
AST_MATCHER(CXXRecordDecl, hasPublicVirtualOrProtectedNonVirtualDestructor)