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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/SmallString.h"
     18 #include "llvm/ADT/StringMap.h"
     19 #include "llvm/IR/Value.h"
     20 #include "llvm/Support/DataTypes.h"
     21 
     22 namespace llvm {
     23   template <typename ValueSubClass> 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>;
     37   friend class SymbolTableListTraits<BasicBlock>;
     38   friend class SymbolTableListTraits<Instruction>;
     39   friend class SymbolTableListTraits<Function>;
     40   friend class SymbolTableListTraits<GlobalVariable>;
     41   friend class SymbolTableListTraits<GlobalAlias>;
     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   ValueSymbolTable() : vmap(0), LastUnique(0) {}
     59   ~ValueSymbolTable();
     60 
     61 /// @}
     62 /// @name Accessors
     63 /// @{
     64 public:
     65   /// This method finds the value with the given \p Name in the
     66   /// the symbol table.
     67   /// @returns the value associated with the \p Name
     68   /// @brief Lookup a named Value.
     69   Value *lookup(StringRef Name) const { return vmap.lookup(Name); }
     70 
     71   /// @returns true iff the symbol table is empty
     72   /// @brief Determine if the symbol table is empty
     73   inline bool empty() const { return vmap.empty(); }
     74 
     75   /// @brief The number of name/type pairs is returned.
     76   inline unsigned size() const { return unsigned(vmap.size()); }
     77 
     78   /// This function can be used from the debugger to display the
     79   /// content of the symbol table while debugging.
     80   /// @brief Print out symbol table on stderr
     81   void dump() const;
     82 
     83 /// @}
     84 /// @name Iteration
     85 /// @{
     86 public:
     87   /// @brief Get an iterator that from the beginning of the symbol table.
     88   inline iterator begin() { return vmap.begin(); }
     89 
     90   /// @brief Get a const_iterator that from the beginning of the symbol table.
     91   inline const_iterator begin() const { return vmap.begin(); }
     92 
     93   /// @brief Get an iterator to the end of the symbol table.
     94   inline iterator end() { return vmap.end(); }
     95 
     96   /// @brief Get a const_iterator to the end of the symbol table.
     97   inline const_iterator end() const { return vmap.end(); }
     98 
     99   /// @}
    100   /// @name Mutators
    101   /// @{
    102 private:
    103   ValueName *makeUniqueName(Value *V, SmallString<256> &UniqueName);
    104 
    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