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 <bool ExtraIteratorBits> struct ilist_iterator_bits; 31 template <unsigned InternalLen> class SmallString; 32 template <typename ValueSubClass, typename ... Args> class SymbolTableListTraits; 33 34 /// This class provides a symbol table of name/value pairs. It is essentially 35 /// a std::map<std::string,Value*> but has a controlled interface provided by 36 /// LLVM as well as ensuring uniqueness of names. 37 /// 38 class ValueSymbolTable { 39 friend class SymbolTableListTraits<Argument>; 40 friend class SymbolTableListTraits<BasicBlock>; 41 friend class SymbolTableListTraits<Function>; 42 friend class SymbolTableListTraits<GlobalAlias>; 43 friend class SymbolTableListTraits<GlobalIFunc>; 44 friend class SymbolTableListTraits<GlobalVariable>; 45 friend class SymbolTableListTraits<Instruction, ilist_iterator_bits<true>>; 46 friend class Value; 47 48 /// @name Types 49 /// @{ 50 public: 51 /// A mapping of names to values. 52 using ValueMap = StringMap<Value*>; 53 54 /// An iterator over a ValueMap. 55 using iterator = ValueMap::iterator; 56 57 /// A const_iterator over a ValueMap. 58 using const_iterator = ValueMap::const_iterator; 59 60 /// @} 61 /// @name Constructors 62 /// @{ 63 64 ValueSymbolTable(int MaxNameSize = -1) : vmap(0), MaxNameSize(MaxNameSize) {} 65 ~ValueSymbolTable(); 66 67 /// @} 68 /// @name Accessors 69 /// @{ 70 71 /// This method finds the value with the given \p Name in the 72 /// the symbol table. 73 /// @returns the value associated with the \p Name 74 /// Lookup a named Value. 75 Value *lookup(StringRef Name) const { 76 if (MaxNameSize > -1 && Name.size() > (unsigned)MaxNameSize) 77 Name = Name.substr(0, std::max(1u, (unsigned)MaxNameSize)); 78 79 return vmap.lookup(Name); 80 } 81 82 /// @returns true iff the symbol table is empty 83 /// Determine if the symbol table is empty 84 inline bool empty() const { return vmap.empty(); } 85 86 /// The number of name/type pairs is returned. 87 inline unsigned size() const { return unsigned(vmap.size()); } 88 89 /// This function can be used from the debugger to display the 90 /// content of the symbol table while debugging. 91 /// Print out symbol table on stderr 92 void dump() const; 93 94 /// @} 95 /// @name Iteration 96 /// @{ 97 98 /// Get an iterator that from the beginning of the symbol table. 99 inline iterator begin() { return vmap.begin(); } 100 101 /// Get a const_iterator that from the beginning of the symbol table. 102 inline const_iterator begin() const { return vmap.begin(); } 103 104 /// Get an iterator to the end of the symbol table. 105 inline iterator end() { return vmap.end(); } 106 107 /// Get a const_iterator to the end of the symbol table. 108 inline const_iterator end() const { return vmap.end(); } 109 110 /// @} 111 /// @name Mutators 112 /// @{ 113 private: 114 ValueName *makeUniqueName(Value *V, SmallString<256> &UniqueName); 115 116 /// This method adds the provided value \p N to the symbol table. The Value 117 /// must have a name which is used to place the value in the symbol table. 118 /// If the inserted name conflicts, this renames the value. 119 /// Add a named value to the symbol table 120 void reinsertValue(Value *V); 121 122 /// createValueName - This method attempts to create a value name and insert 123 /// it into the symbol table with the specified name. If it conflicts, it 124 /// auto-renames the name and returns that instead. 125 ValueName *createValueName(StringRef Name, Value *V); 126 127 /// This method removes a value from the symbol table. It leaves the 128 /// ValueName attached to the value, but it is no longer inserted in the 129 /// symtab. 130 void removeValueName(ValueName *V); 131 132 /// @} 133 /// @name Internal Data 134 /// @{ 135 136 ValueMap vmap; ///< The map that holds the symbol table. 137 int MaxNameSize; ///< The maximum size for each name. If the limit is 138 ///< exceeded, the name is capped. 139 mutable uint32_t LastUnique = 0; ///< Counter for tracking unique names 140 141 /// @} 142 }; 143 144 } // end namespace llvm 145 146 #endif // LLVM_IR_VALUESYMBOLTABLE_H 147