1//===- SymExpr.h - Management of Symbolic 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 defines SymExpr and SymbolData. 10// 11//===----------------------------------------------------------------------===// 12 13#ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SYMEXPR_H 14#define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SYMEXPR_H 15 16#include "clang/AST/Type.h" 17#include "clang/Basic/LLVM.h" 18#include "llvm/ADT/FoldingSet.h" 19#include "llvm/ADT/SmallVector.h" 20#include "llvm/ADT/iterator_range.h" 21#include <cassert> 22 23namespace clang { 24namespace ento { 25 26class MemRegion; 27 28/// Symbolic value. These values used to capture symbolic execution of 29/// the program. 30class SymExpr : public llvm::FoldingSetNode { 31 virtual void anchor(); 32 33public: 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 40private: 41 Kind K; 42 43protected: 44 SymExpr(Kind k) : K(k) {} 45 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 54public: 55 virtual ~SymExpr() = default; 56 57 Kind getKind() const { return K; } 58 59 virtual void dump() const; 60 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 87 llvm::iterator_range<symbol_iterator> symbols() const { 88 return llvm::make_range(symbol_iterator(this), symbol_iterator()); 89 } 90 91 virtual unsigned computeComplexity() const = 0; 92 93 /// Find the region from which this symbol originates. 94 /// 95 /// Whenever the symbol was constructed to denote an unknown value of 96 /// a certain memory region, return this region. This method 97 /// allows checkers to make decisions depending on the origin of the symbol. 98 /// Symbol classes for which the origin region is known include 99 /// SymbolRegionValue which denotes the value of the region before 100 /// the beginning of the analysis, and SymbolDerived which denotes the value 101 /// of a certain memory region after its super region (a memory space or 102 /// a larger record region) is default-bound with a certain symbol. 103 /// It might return null. 104 virtual const MemRegion *getOriginRegion() const { return nullptr; } 105}; 106 107inline raw_ostream &operator<<(raw_ostream &os, 108 const clang::ento::SymExpr *SE) { 109 SE->dumpToStream(os); 110 return os; 111} 112 113using SymbolRef = const SymExpr *; 114using SymbolRefSmallVectorTy = SmallVector<SymbolRef, 2>; 115using SymbolID = unsigned; 116 117/// A symbol representing data which can be stored in a memory location 118/// (region). 119class SymbolData : public SymExpr { 120 const SymbolID Sym; 121 122 void anchor() override; 123 124protected: 125 SymbolData(Kind k, SymbolID sym) : SymExpr(k), Sym(sym) { 126 assert(classof(this)); 127 } 128 129public: 130 ~SymbolData() override = default; 131 132 /// Get a string representation of the kind of the region. 133 virtual StringRef getKindStr() const = 0; 134 135 SymbolID getSymbolID() const { return Sym; } 136 137 unsigned computeComplexity() const override { 138 return 1; 139 }; 140 141 // Implement isa<T> support. 142 static inline bool classof(const SymExpr *SE) { 143 Kind k = SE->getKind(); 144 return k >= BEGIN_SYMBOLS && k <= END_SYMBOLS; 145 } 146}; 147 148} // namespace ento 149} // namespace clang 150 151#endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SYMEXPR_H 152