1 //===- Environment.h - Map from Stmt* to Locations/Values -------*- 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 defined the Environment and EnvironmentManager classes.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_ENVIRONMENT_H
14 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_ENVIRONMENT_H
15 
16 #include "clang/Analysis/AnalysisDeclContext.h"
17 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState_Fwd.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
19 #include "llvm/ADT/ImmutableMap.h"
20 #include <utility>
21 
22 namespace clang {
23 
24 class Stmt;
25 
26 namespace ento {
27 
28 class SValBuilder;
29 class SymbolReaper;
30 
31 /// An entry in the environment consists of a Stmt and an LocationContext.
32 /// This allows the environment to manage context-sensitive bindings,
33 /// which is essentially for modeling recursive function analysis, among
34 /// other things.
35 class EnvironmentEntry : public std::pair<const Stmt *,
36                                           const StackFrameContext *> {
37 public:
38   EnvironmentEntry(const Stmt *s, const LocationContext *L);
39 
40   const Stmt *getStmt() const { return first; }
41   const LocationContext *getLocationContext() const { return second; }
42 
43   /// Profile an EnvironmentEntry for inclusion in a FoldingSet.
44   static void Profile(llvm::FoldingSetNodeID &ID,
45                       const EnvironmentEntry &E) {
46     ID.AddPointer(E.getStmt());
47     ID.AddPointer(E.getLocationContext());
48   }
49 
50   void Profile(llvm::FoldingSetNodeID &ID) const {
51     Profile(ID, *this);
52   }
53 };
54 
55 /// An immutable map from EnvironemntEntries to SVals.
56 class Environment {
57 private:
58   friend class EnvironmentManager;
59 
60   using BindingsTy = llvm::ImmutableMap<EnvironmentEntry, SVal>;
61 
62   BindingsTy ExprBindings;
63 
64   Environment(BindingsTy eb) : ExprBindings(eb) {}
65 
66   SVal lookupExpr(const EnvironmentEntry &E) const;
67 
68 public:
69   using iterator = BindingsTy::iterator;
70 
71   iterator begin() const { return ExprBindings.begin(); }
72   iterator end() const { return ExprBindings.end(); }
73 
74   /// Fetches the current binding of the expression in the
75   /// Environment.
76   SVal getSVal(const EnvironmentEntry &E, SValBuilder &svalBuilder) const;
77 
78   /// Profile - Profile the contents of an Environment object for use
79   ///  in a FoldingSet.
80   static void Profile(llvm::FoldingSetNodeID& ID, const Environment* env) {
81     env->ExprBindings.Profile(ID);
82   }
83 
84   /// Profile - Used to profile the contents of this object for inclusion
85   ///  in a FoldingSet.
86   void Profile(llvm::FoldingSetNodeID& ID) const {
87     Profile(ID, this);
88   }
89 
90   bool operator==(const Environment& RHS) const {
91     return ExprBindings == RHS.ExprBindings;
92   }
93 
94   void printJson(raw_ostream &Out, const ASTContext &Ctx,
95                  const LocationContext *LCtx = nullptr, const char *NL = "\n",
96                  unsigned int Space = 0, bool IsDot = false) const;
97 };
98 
99 class EnvironmentManager {
100 private:
101   using FactoryTy = Environment::BindingsTy::Factory;
102 
103   FactoryTy F;
104 
105 public:
106   EnvironmentManager(llvm::BumpPtrAllocator &Allocator) : F(Allocator) {}
107 
108   Environment getInitialEnvironment() {
109     return Environment(F.getEmptyMap());
110   }
111 
112   /// Bind a symbolic value to the given environment entry.
113   Environment bindExpr(Environment Env, const EnvironmentEntry &E, SVal V,
114                        bool Invalidate);
115 
116   Environment removeDeadBindings(Environment Env,
117                                  SymbolReaper &SymReaper,
118                                  ProgramStateRef state);
119 };
120 
121 } // namespace ento
122 
123 } // namespace clang
124 
125 #endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_ENVIRONMENT_H
126