1 //===-- UncheckedOptionalAccessModel.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 file defines a dataflow analysis that detects unsafe uses of optional 10 // values. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef CLANG_ANALYSIS_FLOWSENSITIVE_MODELS_UNCHECKEDOPTIONALACCESSMODEL_H 15 #define CLANG_ANALYSIS_FLOWSENSITIVE_MODELS_UNCHECKEDOPTIONALACCESSMODEL_H 16 17 #include "clang/AST/ASTContext.h" 18 #include "clang/AST/Stmt.h" 19 #include "clang/Analysis/FlowSensitive/DataflowAnalysis.h" 20 #include "clang/Analysis/FlowSensitive/DataflowEnvironment.h" 21 #include "clang/Analysis/FlowSensitive/MatchSwitch.h" 22 #include "clang/Analysis/FlowSensitive/NoopLattice.h" 23 #include "clang/Basic/SourceLocation.h" 24 #include <vector> 25 26 namespace clang { 27 namespace dataflow { 28 29 // FIXME: Explore using an allowlist-approach, where constructs supported by the 30 // analysis are always enabled and additional constructs are enabled through the 31 // `Options`. 32 struct UncheckedOptionalAccessModelOptions { 33 /// Ignore optionals reachable through overloaded `operator*` or `operator->` 34 /// (other than those of the optional type itself). The analysis does not 35 /// equate the results of such calls, so it can't identify when their results 36 /// are used safely (across calls), resulting in false positives in all such 37 /// cases. Note: this option does not cover access through `operator[]`. 38 bool IgnoreSmartPointerDereference = false; 39 }; 40 41 /// Dataflow analysis that models whether optionals hold values or not. 42 /// 43 /// Models the `std::optional`, `absl::optional`, and `base::Optional` types. 44 class UncheckedOptionalAccessModel 45 : public DataflowAnalysis<UncheckedOptionalAccessModel, NoopLattice> { 46 public: 47 UncheckedOptionalAccessModel( 48 ASTContext &AstContext, UncheckedOptionalAccessModelOptions Options = {}); 49 50 /// Returns a matcher for the optional classes covered by this model. 51 static ast_matchers::DeclarationMatcher optionalClassDecl(); 52 53 static NoopLattice initialElement() { return {}; } 54 55 void transfer(const Stmt *Stmt, NoopLattice &State, Environment &Env); 56 57 bool compareEquivalent(QualType Type, const Value &Val1, 58 const Environment &Env1, const Value &Val2, 59 const Environment &Env2) override; 60 61 bool merge(QualType Type, const Value &Val1, const Environment &Env1, 62 const Value &Val2, const Environment &Env2, Value &MergedVal, 63 Environment &MergedEnv) override; 64 65 private: 66 MatchSwitch<TransferState<NoopLattice>> TransferMatchSwitch; 67 }; 68 69 class UncheckedOptionalAccessDiagnoser { 70 public: 71 UncheckedOptionalAccessDiagnoser( 72 UncheckedOptionalAccessModelOptions Options = {}); 73 74 std::vector<SourceLocation> diagnose(ASTContext &Context, const Stmt *Stmt, 75 const Environment &Env); 76 77 private: 78 MatchSwitch<const Environment, std::vector<SourceLocation>> 79 DiagnoseMatchSwitch; 80 }; 81 82 } // namespace dataflow 83 } // namespace clang 84 85 #endif // CLANG_ANALYSIS_FLOWSENSITIVE_MODELS_UNCHECKEDOPTIONALACCESSMODEL_H 86