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