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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 
30 /// An entry in the environment consists of a Stmt and an LocationContext.
31 /// This allows the environment to manage context-sensitive bindings,
32 /// which is essentially for modeling recursive function analysis, among
33 /// other things.
34 class EnvironmentEntry : public std::pair<const Stmt*,
35                                           const StackFrameContext *> {
36 public:
37   EnvironmentEntry(const Stmt *s, const LocationContext *L);
38 
getStmt()39   const Stmt *getStmt() const { return first; }
getLocationContext()40   const LocationContext *getLocationContext() const { return second; }
41 
42   /// Profile an EnvironmentEntry for inclusion in a FoldingSet.
Profile(llvm::FoldingSetNodeID & ID,const EnvironmentEntry & E)43   static void Profile(llvm::FoldingSetNodeID &ID,
44                       const EnvironmentEntry &E) {
45     ID.AddPointer(E.getStmt());
46     ID.AddPointer(E.getLocationContext());
47   }
48 
Profile(llvm::FoldingSetNodeID & ID)49   void Profile(llvm::FoldingSetNodeID &ID) const {
50     Profile(ID, *this);
51   }
52 };
53 
54 /// An immutable map from EnvironemntEntries to SVals.
55 class Environment {
56 private:
57   friend class EnvironmentManager;
58 
59   // Type definitions.
60   typedef llvm::ImmutableMap<EnvironmentEntry, SVal> BindingsTy;
61 
62   // Data.
63   BindingsTy ExprBindings;
64 
Environment(BindingsTy eb)65   Environment(BindingsTy eb)
66     : ExprBindings(eb) {}
67 
68   SVal lookupExpr(const EnvironmentEntry &E) const;
69 
70 public:
71   typedef BindingsTy::iterator iterator;
begin()72   iterator begin() const { return ExprBindings.begin(); }
end()73   iterator end() const { return ExprBindings.end(); }
74 
75   /// Fetches the current binding of the expression in the
76   /// Environment.
77   SVal getSVal(const EnvironmentEntry &E, SValBuilder &svalBuilder) const;
78 
79   /// Profile - Profile the contents of an Environment object for use
80   ///  in a FoldingSet.
Profile(llvm::FoldingSetNodeID & ID,const Environment * env)81   static void Profile(llvm::FoldingSetNodeID& ID, const Environment* env) {
82     env->ExprBindings.Profile(ID);
83   }
84 
85   /// Profile - Used to profile the contents of this object for inclusion
86   ///  in a FoldingSet.
Profile(llvm::FoldingSetNodeID & ID)87   void Profile(llvm::FoldingSetNodeID& ID) const {
88     Profile(ID, this);
89   }
90 
91   bool operator==(const Environment& RHS) const {
92     return ExprBindings == RHS.ExprBindings;
93   }
94 
95   void print(raw_ostream &Out, const char *NL, const char *Sep) const;
96 
97 private:
98   void printAux(raw_ostream &Out, bool printLocations,
99                 const char *NL, const char *Sep) const;
100 };
101 
102 class EnvironmentManager {
103 private:
104   typedef Environment::BindingsTy::Factory FactoryTy;
105   FactoryTy F;
106 
107 public:
EnvironmentManager(llvm::BumpPtrAllocator & Allocator)108   EnvironmentManager(llvm::BumpPtrAllocator& Allocator) : F(Allocator) {}
109 
getInitialEnvironment()110   Environment getInitialEnvironment() {
111     return Environment(F.getEmptyMap());
112   }
113 
114   /// Bind a symbolic value to the given environment entry.
115   Environment bindExpr(Environment Env, const EnvironmentEntry &E, SVal V,
116                        bool Invalidate);
117 
118   Environment removeDeadBindings(Environment Env,
119                                  SymbolReaper &SymReaper,
120                                  ProgramStateRef state);
121 };
122 
123 } // end GR namespace
124 
125 } // end clang namespace
126 
127 #endif
128