clang/lib/StaticAnalyzer/Checkers/TrustReturnsNonnullChecker.cpp

   1 //== TrustReturnsNonnullChecker.cpp -- API nullability modeling -*- 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 checker adds nullability-related assumptions to methods annotated with
  10 // returns_nonnull attribute.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "clang/AST/Attr.h"
  15 #include "clang/AST/Decl.h"
  16 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
  17 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
  18 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
  19
  20 using namespace clang;
  21 using namespace ento;
  22
  23 namespace {
  24
  25 class TrustReturnsNonnullChecker : public Checker<check::PostCall> {
  26
  27 public:
  28   TrustReturnsNonnullChecker(ASTContext &Ctx) {}
  29
  30   void checkPostCall(const CallEvent &Call, CheckerContext &C) const {
  31     ProgramStateRef State = C.getState();
  32
  33     if (isNonNullPtr(Call))
  34       if (auto L = Call.getReturnValue().getAs<Loc>())
  35         State = State->assume(*L, /*assumption=*/true);
  36
  37     C.addTransition(State);
  38   }
  39
  40 private:
  41   /// \returns Whether the method declaration has the attribute returns_nonnull.
  42   bool isNonNullPtr(const CallEvent &Call) const {
  43     QualType ExprRetType = Call.getResultType();
  44     const Decl *CallDeclaration =  Call.getDecl();
  45     if (!ExprRetType->isAnyPointerType() || !CallDeclaration)
  46       return false;
  47
  48     return CallDeclaration->hasAttr<ReturnsNonNullAttr>();
  49   }
  50 };
  51
  52 } // namespace
  53
  54 void ento::registerTrustReturnsNonnullChecker(CheckerManager &Mgr) {
  55   Mgr.registerChecker<TrustReturnsNonnullChecker>(Mgr.getASTContext());
  56 }
  57
  58 bool ento::shouldRegisterTrustReturnsNonnullChecker(const CheckerManager &mgr) {
  59   return true;
  60 }