clang/lib/StaticAnalyzer/Checkers/UndefinedArraySubscriptChecker.cpp

   1 //===--- UndefinedArraySubscriptChecker.h ----------------------*- C++ -*--===//
   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 // This defines UndefinedArraySubscriptChecker, a builtin check in ExprEngine
  10 // that performs checks for undefined array subscripts.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
  15 #include "clang/AST/DeclCXX.h"
  16 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
  17 #include "clang/StaticAnalyzer/Core/Checker.h"
  18 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
  19 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
  20
  21 using namespace clang;
  22 using namespace ento;
  23
  24 namespace {
  25 class UndefinedArraySubscriptChecker
  26   : public Checker< check::PreStmt<ArraySubscriptExpr> > {
  27   mutable std::unique_ptr<BugType> BT;
  28
  29 public:
  30   void checkPreStmt(const ArraySubscriptExpr *A, CheckerContext &C) const;
  31 };
  32 } // end anonymous namespace
  33
  34 void
  35 UndefinedArraySubscriptChecker::checkPreStmt(const ArraySubscriptExpr *A,
  36                                              CheckerContext &C) const {
  37   const Expr *Index = A->getIdx();
  38   if (!C.getSVal(Index).isUndef())
  39     return;
  40
  41   // Sema generates anonymous array variables for copying array struct fields.
  42   // Don't warn if we're in an implicitly-generated constructor.
  43   const Decl *D = C.getLocationContext()->getDecl();
  44   if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(D))
  45     if (Ctor->isDefaulted())
  46       return;
  47
  48   ExplodedNode *N = C.generateErrorNode();
  49   if (!N)
  50     return;
  51   if (!BT)
  52     BT.reset(new BugType(this, "Array subscript is undefined"));
  53
  54   // Generate a report for this bug.
  55   auto R = std::make_unique<PathSensitiveBugReport>(*BT, BT->getDescription(), N);
  56   R->addRange(A->getIdx()->getSourceRange());
  57   bugreporter::trackExpressionValue(N, A->getIdx(), *R);
  58   C.emitReport(std::move(R));
  59 }
  60
  61 void ento::registerUndefinedArraySubscriptChecker(CheckerManager &mgr) {
  62   mgr.registerChecker<UndefinedArraySubscriptChecker>();
  63 }
  64
  65 bool ento::shouldRegisterUndefinedArraySubscriptChecker(const CheckerManager &mgr) {
  66   return true;
  67 }