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1 //== Environment.h - Map from Stmt* to Locations/Values ---------*- C++ -*--==//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file defined the Environment and EnvironmentManager classes.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_ENVIRONMENT_H
15 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_ENVIRONMENT_H
16 
17 #include "clang/Analysis/AnalysisContext.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
19 #include "llvm/ADT/ImmutableMap.h"
20 
21 namespace clang {
22 
23 class LiveVariables;
24 
25 namespace ento {
26 
27 class EnvironmentManager;
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 
getStmt()40   const Stmt *getStmt() const { return first; }
getLocationContext()41   const LocationContext *getLocationContext() const { return second; }
42 
43   /// Profile an EnvironmentEntry for inclusion in a FoldingSet.
Profile(llvm::FoldingSetNodeID & ID,const EnvironmentEntry & E)44   static void Profile(llvm::FoldingSetNodeID &ID,
45                       const EnvironmentEntry &E) {
46     ID.AddPointer(E.getStmt());
47     ID.AddPointer(E.getLocationContext());
48   }
49 
Profile(llvm::FoldingSetNodeID & ID)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   // Type definitions.
61   typedef llvm::ImmutableMap<EnvironmentEntry, SVal> BindingsTy;
62 
63   // Data.
64   BindingsTy ExprBindings;
65 
Environment(BindingsTy eb)66   Environment(BindingsTy eb)
67     : ExprBindings(eb) {}
68 
69   SVal lookupExpr(const EnvironmentEntry &E) const;
70 
71 public:
72   typedef BindingsTy::iterator iterator;
begin()73   iterator begin() const { return ExprBindings.begin(); }
end()74   iterator end() const { return ExprBindings.end(); }
75 
76   /// Fetches the current binding of the expression in the
77   /// Environment.
78   SVal getSVal(const EnvironmentEntry &E, SValBuilder &svalBuilder) const;
79 
80   /// Profile - Profile the contents of an Environment object for use
81   ///  in a FoldingSet.
Profile(llvm::FoldingSetNodeID & ID,const Environment * env)82   static void Profile(llvm::FoldingSetNodeID& ID, const Environment* env) {
83     env->ExprBindings.Profile(ID);
84   }
85 
86   /// Profile - Used to profile the contents of this object for inclusion
87   ///  in a FoldingSet.
Profile(llvm::FoldingSetNodeID & ID)88   void Profile(llvm::FoldingSetNodeID& ID) const {
89     Profile(ID, this);
90   }
91 
92   bool operator==(const Environment& RHS) const {
93     return ExprBindings == RHS.ExprBindings;
94   }
95 
96   void print(raw_ostream &Out, const char *NL, const char *Sep) const;
97 
98 private:
99   void printAux(raw_ostream &Out, bool printLocations,
100                 const char *NL, const char *Sep) const;
101 };
102 
103 class EnvironmentManager {
104 private:
105   typedef Environment::BindingsTy::Factory FactoryTy;
106   FactoryTy F;
107 
108 public:
EnvironmentManager(llvm::BumpPtrAllocator & Allocator)109   EnvironmentManager(llvm::BumpPtrAllocator& Allocator) : F(Allocator) {}
110 
getInitialEnvironment()111   Environment getInitialEnvironment() {
112     return Environment(F.getEmptyMap());
113   }
114 
115   /// Bind a symbolic value to the given environment entry.
116   Environment bindExpr(Environment Env, const EnvironmentEntry &E, SVal V,
117                        bool Invalidate);
118 
119   Environment removeDeadBindings(Environment Env,
120                                  SymbolReaper &SymReaper,
121                                  ProgramStateRef state);
122 };
123 
124 } // end GR namespace
125 
126 } // end clang namespace
127 
128 #endif
129