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 "clang/Basic/LLVM.h" 19 #include "llvm/ADT/FoldingSet.h" 20 #include "llvm/ADT/SmallVector.h" 21 #include <cassert> 22 23 namespace clang { 24 namespace ento { 25 26 class MemRegion; 27 28 /// Symbolic value. These values used to capture symbolic execution of 29 /// the program. 30 class SymExpr : public llvm::FoldingSetNode { 31 virtual void anchor(); 32 33 public: 34 enum Kind { 35 #define SYMBOL(Id, Parent) Id##Kind, 36 #define SYMBOL_RANGE(Id, First, Last) BEGIN_##Id = First, END_##Id = Last, 37 #include "clang/StaticAnalyzer/Core/PathSensitive/Symbols.def" 38 }; 39 40 private: 41 Kind K; 42 43 protected: SymExpr(Kind k)44 SymExpr(Kind k) : K(k) {} 45 isValidTypeForSymbol(QualType T)46 static bool isValidTypeForSymbol(QualType T) { 47 // FIXME: Depending on whether we choose to deprecate structural symbols, 48 // this may become much stricter. 49 return !T.isNull() && !T->isVoidType(); 50 } 51 52 mutable unsigned Complexity = 0; 53 54 public: 55 virtual ~SymExpr() = default; 56 getKind()57 Kind getKind() const { return K; } 58 59 virtual void dump() const; 60 dumpToStream(raw_ostream & os)61 virtual void dumpToStream(raw_ostream &os) const {} 62 63 virtual QualType getType() const = 0; 64 virtual void Profile(llvm::FoldingSetNodeID &profile) = 0; 65 66 /// Iterator over symbols that the current symbol depends on. 67 /// 68 /// For SymbolData, it's the symbol itself; for expressions, it's the 69 /// expression symbol and all the operands in it. Note, SymbolDerived is 70 /// treated as SymbolData - the iterator will NOT visit the parent region. 71 class symbol_iterator { 72 SmallVector<const SymExpr *, 5> itr; 73 74 void expand(); 75 76 public: 77 symbol_iterator() = default; 78 symbol_iterator(const SymExpr *SE); 79 80 symbol_iterator &operator++(); 81 const SymExpr *operator*(); 82 83 bool operator==(const symbol_iterator &X) const; 84 bool operator!=(const symbol_iterator &X) const; 85 }; 86 symbol_begin()87 symbol_iterator symbol_begin() const { return symbol_iterator(this); } symbol_end()88 static symbol_iterator symbol_end() { return symbol_iterator(); } 89 90 virtual unsigned computeComplexity() const = 0; 91 92 /// Find the region from which this symbol originates. 93 /// 94 /// Whenever the symbol was constructed to denote an unknown value of 95 /// a certain memory region, return this region. This method 96 /// allows checkers to make decisions depending on the origin of the symbol. 97 /// Symbol classes for which the origin region is known include 98 /// SymbolRegionValue which denotes the value of the region before 99 /// the beginning of the analysis, and SymbolDerived which denotes the value 100 /// of a certain memory region after its super region (a memory space or 101 /// a larger record region) is default-bound with a certain symbol. getOriginRegion()102 virtual const MemRegion *getOriginRegion() const { return nullptr; } 103 }; 104 105 inline raw_ostream &operator<<(raw_ostream &os, 106 const clang::ento::SymExpr *SE) { 107 SE->dumpToStream(os); 108 return os; 109 } 110 111 using SymbolRef = const SymExpr *; 112 using SymbolRefSmallVectorTy = SmallVector<SymbolRef, 2>; 113 using SymbolID = unsigned; 114 115 /// A symbol representing data which can be stored in a memory location 116 /// (region). 117 class SymbolData : public SymExpr { 118 const SymbolID Sym; 119 120 void anchor() override; 121 122 protected: SymbolData(Kind k,SymbolID sym)123 SymbolData(Kind k, SymbolID sym) : SymExpr(k), Sym(sym) { 124 assert(classof(this)); 125 } 126 127 public: 128 ~SymbolData() override = default; 129 getSymbolID()130 SymbolID getSymbolID() const { return Sym; } 131 computeComplexity()132 unsigned computeComplexity() const override { 133 return 1; 134 }; 135 136 // Implement isa<T> support. classof(const SymExpr * SE)137 static inline bool classof(const SymExpr *SE) { 138 Kind k = SE->getKind(); 139 return k >= BEGIN_SYMBOLS && k <= END_SYMBOLS; 140 } 141 }; 142 143 } // namespace ento 144 } // namespace clang 145 146 #endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SYMEXPR_H 147