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 "llvm/Support/Compiler.h" 20 #include <cstdint> 21 22 namespace llvm { 23 24 class Argument; 25 class BasicBlock; 26 class Function; 27 class GlobalAlias; 28 class GlobalIFunc; 29 class GlobalVariable; 30 class Instruction; 31 template <bool ExtraIteratorBits> struct ilist_iterator_bits; 32 template <class ParentTy> struct ilist_parent; 33 template <unsigned InternalLen> class SmallString; 34 template <typename ValueSubClass, typename ... Args> class SymbolTableListTraits; 35 36 /// This class provides a symbol table of name/value pairs. It is essentially 37 /// a std::map<std::string,Value*> but has a controlled interface provided by 38 /// LLVM as well as ensuring uniqueness of names. 39 /// 40 class ValueSymbolTable { 41 friend class SymbolTableListTraits<Argument>; 42 friend class SymbolTableListTraits<BasicBlock>; 43 friend class SymbolTableListTraits<Function>; 44 friend class SymbolTableListTraits<GlobalAlias>; 45 friend class SymbolTableListTraits<GlobalIFunc>; 46 friend class SymbolTableListTraits<GlobalVariable>; 47 friend class SymbolTableListTraits<Instruction, ilist_iterator_bits<true>, 48 ilist_parent<BasicBlock>>; 49 friend class Value; 50 51 /// @name Types 52 /// @{ 53 public: 54 /// A mapping of names to values. 55 using ValueMap = StringMap<Value*>; 56 57 /// An iterator over a ValueMap. 58 using iterator = ValueMap::iterator; 59 60 /// A const_iterator over a ValueMap. 61 using const_iterator = ValueMap::const_iterator; 62 63 /// @} 64 /// @name Constructors 65 /// @{ 66 67 ValueSymbolTable(int MaxNameSize = -1) : vmap(0), MaxNameSize(MaxNameSize) {} 68 LLVM_ABI ~ValueSymbolTable(); 69 70 /// @} 71 /// @name Accessors 72 /// @{ 73 74 /// This method finds the value with the given \p Name in the 75 /// the symbol table. 76 /// @returns the value associated with the \p Name 77 /// Lookup a named Value. lookup(StringRef Name)78 Value *lookup(StringRef Name) const { 79 if (MaxNameSize > -1 && Name.size() > (unsigned)MaxNameSize) 80 Name = Name.substr(0, std::max(1u, (unsigned)MaxNameSize)); 81 82 return vmap.lookup(Name); 83 } 84 85 /// @returns true iff the symbol table is empty 86 /// Determine if the symbol table is empty empty()87 inline bool empty() const { return vmap.empty(); } 88 89 /// The number of name/type pairs is returned. size()90 inline unsigned size() const { return unsigned(vmap.size()); } 91 92 /// This function can be used from the debugger to display the 93 /// content of the symbol table while debugging. 94 /// Print out symbol table on stderr 95 LLVM_ABI void dump() const; 96 97 /// @} 98 /// @name Iteration 99 /// @{ 100 101 /// Get an iterator that from the beginning of the symbol table. begin()102 inline iterator begin() { return vmap.begin(); } 103 104 /// Get a const_iterator that from the beginning of the symbol table. begin()105 inline const_iterator begin() const { return vmap.begin(); } 106 107 /// Get an iterator to the end of the symbol table. end()108 inline iterator end() { return vmap.end(); } 109 110 /// Get a const_iterator to the end of the symbol table. end()111 inline const_iterator end() const { return vmap.end(); } 112 113 /// @} 114 /// @name Mutators 115 /// @{ 116 private: 117 ValueName *makeUniqueName(Value *V, SmallString<256> &UniqueName); 118 119 /// This method adds the provided value \p N to the symbol table. The Value 120 /// must have a name which is used to place the value in the symbol table. 121 /// If the inserted name conflicts, this renames the value. 122 /// Add a named value to the symbol table 123 void reinsertValue(Value *V); 124 125 /// createValueName - This method attempts to create a value name and insert 126 /// it into the symbol table with the specified name. If it conflicts, it 127 /// auto-renames the name and returns that instead. 128 ValueName *createValueName(StringRef Name, Value *V); 129 130 /// This method removes a value from the symbol table. It leaves the 131 /// ValueName attached to the value, but it is no longer inserted in the 132 /// symtab. 133 void removeValueName(ValueName *V); 134 135 /// @} 136 /// @name Internal Data 137 /// @{ 138 139 ValueMap vmap; ///< The map that holds the symbol table. 140 int MaxNameSize; ///< The maximum size for each name. If the limit is 141 ///< exceeded, the name is capped. 142 mutable uint32_t LastUnique = 0; ///< Counter for tracking unique names 143 144 /// @} 145 }; 146 147 } // end namespace llvm 148 149 #endif // LLVM_IR_VALUESYMBOLTABLE_H 150