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1 //== SymExpr.h - Management of Symbolic 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 defines SymExpr and SymbolData.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SYMEXPR_H
15 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SYMEXPR_H
16 
17 #include "clang/AST/Type.h"
18 #include "llvm/ADT/FoldingSet.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/Support/raw_ostream.h"
21 
22 namespace clang {
23 namespace ento {
24 
25 class MemRegion;
26 
27 /// \brief Symbolic value. These values used to capture symbolic execution of
28 /// the program.
29 class SymExpr : public llvm::FoldingSetNode {
30   virtual void anchor();
31 
32 public:
33   enum Kind {
34 #define SYMBOL(Id, Parent) Id##Kind,
35 #define SYMBOL_RANGE(Id, First, Last) BEGIN_##Id = First, END_##Id = Last,
36 #include "clang/StaticAnalyzer/Core/PathSensitive/Symbols.def"
37   };
38 
39 private:
40   Kind K;
41 
42 protected:
SymExpr(Kind k)43   SymExpr(Kind k) : K(k) {}
44 
45 public:
~SymExpr()46   virtual ~SymExpr() {}
47 
getKind()48   Kind getKind() const { return K; }
49 
50   virtual void dump() const;
51 
dumpToStream(raw_ostream & os)52   virtual void dumpToStream(raw_ostream &os) const {}
53 
54   virtual QualType getType() const = 0;
55   virtual void Profile(llvm::FoldingSetNodeID &profile) = 0;
56 
57   /// \brief Iterator over symbols that the current symbol depends on.
58   ///
59   /// For SymbolData, it's the symbol itself; for expressions, it's the
60   /// expression symbol and all the operands in it. Note, SymbolDerived is
61   /// treated as SymbolData - the iterator will NOT visit the parent region.
62   class symbol_iterator {
63     SmallVector<const SymExpr *, 5> itr;
64     void expand();
65 
66   public:
symbol_iterator()67     symbol_iterator() {}
68     symbol_iterator(const SymExpr *SE);
69 
70     symbol_iterator &operator++();
71     const SymExpr *operator*();
72 
73     bool operator==(const symbol_iterator &X) const;
74     bool operator!=(const symbol_iterator &X) const;
75   };
76 
symbol_begin()77   symbol_iterator symbol_begin() const { return symbol_iterator(this); }
symbol_end()78   static symbol_iterator symbol_end() { return symbol_iterator(); }
79 
80   unsigned computeComplexity() const;
81 
82   /// \brief Find the region from which this symbol originates.
83   ///
84   /// Whenever the symbol was constructed to denote an unknown value of
85   /// a certain memory region, return this region. This method
86   /// allows checkers to make decisions depending on the origin of the symbol.
87   /// Symbol classes for which the origin region is known include
88   /// SymbolRegionValue which denotes the value of the region before
89   /// the beginning of the analysis, and SymbolDerived which denotes the value
90   /// of a certain memory region after its super region (a memory space or
91   /// a larger record region) is default-bound with a certain symbol.
getOriginRegion()92   virtual const MemRegion *getOriginRegion() const { return nullptr; }
93 };
94 
95 typedef const SymExpr *SymbolRef;
96 typedef SmallVector<SymbolRef, 2> SymbolRefSmallVectorTy;
97 
98 typedef unsigned SymbolID;
99 /// \brief A symbol representing data which can be stored in a memory location
100 /// (region).
101 class SymbolData : public SymExpr {
102   void anchor() override;
103   const SymbolID Sym;
104 
105 protected:
SymbolData(Kind k,SymbolID sym)106   SymbolData(Kind k, SymbolID sym) : SymExpr(k), Sym(sym) {}
107 
108 public:
~SymbolData()109   ~SymbolData() override {}
110 
getSymbolID()111   SymbolID getSymbolID() const { return Sym; }
112 
113   // Implement isa<T> support.
classof(const SymExpr * SE)114   static inline bool classof(const SymExpr *SE) {
115     Kind k = SE->getKind();
116     return k >= BEGIN_SYMBOLS && k <= END_SYMBOLS;
117   }
118 };
119 
120 } // namespace ento
121 } // namespace clang
122 
123 #endif
124