Core/PathSensitive/Environment.h

0001 //===- Environment.h - Map from Stmt* to Locations/Values -------*- C++ -*-===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008 //
0009 //  This file defined the Environment and EnvironmentManager classes.
0010 //
0011 //===----------------------------------------------------------------------===//
0012
0013 #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_ENVIRONMENT_H
0014 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_ENVIRONMENT_H
0015
0016 #include "clang/Analysis/AnalysisDeclContext.h"
0017 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState_Fwd.h"
0018 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
0019 #include "llvm/ADT/ImmutableMap.h"
0020 #include <utility>
0021
0022 namespace clang {
0023
0024 class Stmt;
0025
0026 namespace ento {
0027
0028 class SValBuilder;
0029 class SymbolReaper;
0030
0031 /// An entry in the environment consists of a Stmt and an LocationContext.
0032 /// This allows the environment to manage context-sensitive bindings,
0033 /// which is essentially for modeling recursive function analysis, among
0034 /// other things.
0035 class EnvironmentEntry : public std::pair<const Stmt *,
0036                                           const StackFrameContext *> {
0037 public:
0038   EnvironmentEntry(const Stmt *s, const LocationContext *L);
0039
0040   const Stmt *getStmt() const { return first; }
0041   const LocationContext *getLocationContext() const { return second; }
0042
0043   /// Profile an EnvironmentEntry for inclusion in a FoldingSet.
0044   static void Profile(llvm::FoldingSetNodeID &ID,
0045                       const EnvironmentEntry &E) {
0046     ID.AddPointer(E.getStmt());
0047     ID.AddPointer(E.getLocationContext());
0048   }
0049
0050   void Profile(llvm::FoldingSetNodeID &ID) const {
0051     Profile(ID, *this);
0052   }
0053 };
0054
0055 /// An immutable map from EnvironemntEntries to SVals.
0056 class Environment {
0057 private:
0058   friend class EnvironmentManager;
0059
0060   using BindingsTy = llvm::ImmutableMap<EnvironmentEntry, SVal>;
0061
0062   BindingsTy ExprBindings;
0063
0064   Environment(BindingsTy eb) : ExprBindings(eb) {}
0065
0066   SVal lookupExpr(const EnvironmentEntry &E) const;
0067
0068 public:
0069   using iterator = BindingsTy::iterator;
0070
0071   iterator begin() const { return ExprBindings.begin(); }
0072   iterator end() const { return ExprBindings.end(); }
0073
0074   /// Fetches the current binding of the expression in the
0075   /// Environment.
0076   SVal getSVal(const EnvironmentEntry &E, SValBuilder &svalBuilder) const;
0077
0078   /// Profile - Profile the contents of an Environment object for use
0079   ///  in a FoldingSet.
0080   static void Profile(llvm::FoldingSetNodeID& ID, const Environment* env) {
0081     env->ExprBindings.Profile(ID);
0082   }
0083
0084   /// Profile - Used to profile the contents of this object for inclusion
0085   ///  in a FoldingSet.
0086   void Profile(llvm::FoldingSetNodeID& ID) const {
0087     Profile(ID, this);
0088   }
0089
0090   bool operator==(const Environment& RHS) const {
0091     return ExprBindings == RHS.ExprBindings;
0092   }
0093
0094   void printJson(raw_ostream &Out, const ASTContext &Ctx,
0095                  const LocationContext *LCtx = nullptr, const char *NL = "\n",
0096                  unsigned int Space = 0, bool IsDot = false) const;
0097 };
0098
0099 class EnvironmentManager {
0100 private:
0101   using FactoryTy = Environment::BindingsTy::Factory;
0102
0103   FactoryTy F;
0104
0105 public:
0106   EnvironmentManager(llvm::BumpPtrAllocator &Allocator) : F(Allocator) {}
0107
0108   Environment getInitialEnvironment() {
0109     return Environment(F.getEmptyMap());
0110   }
0111
0112   /// Bind a symbolic value to the given environment entry.
0113   Environment bindExpr(Environment Env, const EnvironmentEntry &E, SVal V,
0114                        bool Invalidate);
0115
0116   Environment removeDeadBindings(Environment Env,
0117                                  SymbolReaper &SymReaper,
0118                                  ProgramStateRef state);
0119 };
0120
0121 } // namespace ento
0122
0123 } // namespace clang
0124
0125 #endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_ENVIRONMENT_H