1 //===- llvm/ValueSymbolTable.h - Implement a Value Symtab -------*- 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 implements the name/Value symbol table for LLVM. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_IR_VALUESYMBOLTABLE_H 14 #define LLVM_IR_VALUESYMBOLTABLE_H 15 16 #include "llvm/ADT/StringMap.h" 17 #include "llvm/ADT/StringRef.h" 18 #include "llvm/IR/Value.h" 19 #include <cstdint> 20 21 namespace llvm { 22 23 class Argument; 24 class BasicBlock; 25 class Function; 26 class GlobalAlias; 27 class GlobalIFunc; 28 class GlobalVariable; 29 class Instruction; 30 template <unsigned InternalLen> class SmallString; 31 template <typename ValueSubClass> class SymbolTableListTraits; 32 33 /// This class provides a symbol table of name/value pairs. It is essentially 34 /// a std::map<std::string,Value*> but has a controlled interface provided by 35 /// LLVM as well as ensuring uniqueness of names. 36 /// 37 class ValueSymbolTable { 38 friend class SymbolTableListTraits<Argument>; 39 friend class SymbolTableListTraits<BasicBlock>; 40 friend class SymbolTableListTraits<Function>; 41 friend class SymbolTableListTraits<GlobalAlias>; 42 friend class SymbolTableListTraits<GlobalIFunc>; 43 friend class SymbolTableListTraits<GlobalVariable>; 44 friend class SymbolTableListTraits<Instruction>; 45 friend class Value; 46 47 /// @name Types 48 /// @{ 49 public: 50 /// A mapping of names to values. 51 using ValueMap = StringMap<Value*>; 52 53 /// An iterator over a ValueMap. 54 using iterator = ValueMap::iterator; 55 56 /// A const_iterator over a ValueMap. 57 using const_iterator = ValueMap::const_iterator; 58 59 /// @} 60 /// @name Constructors 61 /// @{ 62 63 ValueSymbolTable(int MaxNameSize = -1) : vmap(0), MaxNameSize(MaxNameSize) {} 64 ~ValueSymbolTable(); 65 66 /// @} 67 /// @name Accessors 68 /// @{ 69 70 /// This method finds the value with the given \p Name in the 71 /// the symbol table. 72 /// @returns the value associated with the \p Name 73 /// Lookup a named Value. 74 Value *lookup(StringRef Name) const { 75 if (MaxNameSize > -1 && Name.size() > (unsigned)MaxNameSize) 76 Name = Name.substr(0, std::max(1u, (unsigned)MaxNameSize)); 77 78 return vmap.lookup(Name); 79 } 80 81 /// @returns true iff the symbol table is empty 82 /// Determine if the symbol table is empty 83 inline bool empty() const { return vmap.empty(); } 84 85 /// The number of name/type pairs is returned. 86 inline unsigned size() const { return unsigned(vmap.size()); } 87 88 /// This function can be used from the debugger to display the 89 /// content of the symbol table while debugging. 90 /// Print out symbol table on stderr 91 void dump() const; 92 93 /// @} 94 /// @name Iteration 95 /// @{ 96 97 /// Get an iterator that from the beginning of the symbol table. 98 inline iterator begin() { return vmap.begin(); } 99 100 /// Get a const_iterator that from the beginning of the symbol table. 101 inline const_iterator begin() const { return vmap.begin(); } 102 103 /// Get an iterator to the end of the symbol table. 104 inline iterator end() { return vmap.end(); } 105 106 /// Get a const_iterator to the end of the symbol table. 107 inline const_iterator end() const { return vmap.end(); } 108 109 /// @} 110 /// @name Mutators 111 /// @{ 112 private: 113 ValueName *makeUniqueName(Value *V, SmallString<256> &UniqueName); 114 115 /// This method adds the provided value \p N to the symbol table. The Value 116 /// must have a name which is used to place the value in the symbol table. 117 /// If the inserted name conflicts, this renames the value. 118 /// Add a named value to the symbol table 119 void reinsertValue(Value *V); 120 121 /// createValueName - This method attempts to create a value name and insert 122 /// it into the symbol table with the specified name. If it conflicts, it 123 /// auto-renames the name and returns that instead. 124 ValueName *createValueName(StringRef Name, Value *V); 125 126 /// This method removes a value from the symbol table. It leaves the 127 /// ValueName attached to the value, but it is no longer inserted in the 128 /// symtab. 129 void removeValueName(ValueName *V); 130 131 /// @} 132 /// @name Internal Data 133 /// @{ 134 135 ValueMap vmap; ///< The map that holds the symbol table. 136 int MaxNameSize; ///< The maximum size for each name. If the limit is 137 ///< exceeded, the name is capped. 138 mutable uint32_t LastUnique = 0; ///< Counter for tracking unique names 139 140 /// @} 141 }; 142 143 } // end namespace llvm 144 145 #endif // LLVM_IR_VALUESYMBOLTABLE_H 146