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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> class SymbolTableListTraits;
     23   template <unsigned InternalLen> class SmallString;
     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   friend class SymbolTableListTraits<GlobalIFunc>;
     43 /// @name Types
     44 /// @{
     45 public:
     46   /// @brief A mapping of names to values.
     47   typedef StringMap<Value*> ValueMap;
     48 
     49   /// @brief An iterator over a ValueMap.
     50   typedef ValueMap::iterator iterator;
     51 
     52   /// @brief A const_iterator over a ValueMap.
     53   typedef ValueMap::const_iterator const_iterator;
     54 
     55 /// @}
     56 /// @name Constructors
     57 /// @{
     58 public:
     59   ValueSymbolTable() : vmap(0), LastUnique(0) {}
     60   ~ValueSymbolTable();
     61 
     62 /// @}
     63 /// @name Accessors
     64 /// @{
     65 public:
     66   /// This method finds the value with the given \p Name in the
     67   /// the symbol table.
     68   /// @returns the value associated with the \p Name
     69   /// @brief Lookup a named Value.
     70   Value *lookup(StringRef Name) const { return vmap.lookup(Name); }
     71 
     72   /// @returns true iff the symbol table is empty
     73   /// @brief Determine if the symbol table is empty
     74   inline bool empty() const { return vmap.empty(); }
     75 
     76   /// @brief The number of name/type pairs is returned.
     77   inline unsigned size() const { return unsigned(vmap.size()); }
     78 
     79   /// This function can be used from the debugger to display the
     80   /// content of the symbol table while debugging.
     81   /// @brief Print out symbol table on stderr
     82   void dump() const;
     83 
     84 /// @}
     85 /// @name Iteration
     86 /// @{
     87 public:
     88   /// @brief Get an iterator that from the beginning of the symbol table.
     89   inline iterator begin() { return vmap.begin(); }
     90 
     91   /// @brief Get a const_iterator that from the beginning of the symbol table.
     92   inline const_iterator begin() const { return vmap.begin(); }
     93 
     94   /// @brief Get an iterator to the end of the symbol table.
     95   inline iterator end() { return vmap.end(); }
     96 
     97   /// @brief Get a const_iterator to the end of the symbol table.
     98   inline const_iterator end() const { return vmap.end(); }
     99 
    100   /// @}
    101   /// @name Mutators
    102   /// @{
    103 private:
    104   ValueName *makeUniqueName(Value *V, SmallString<256> &UniqueName);
    105 
    106   /// This method adds the provided value \p N to the symbol table.  The Value
    107   /// must have a name which is used to place the value in the symbol table.
    108   /// If the inserted name conflicts, this renames the value.
    109   /// @brief Add a named value to the symbol table
    110   void reinsertValue(Value *V);
    111 
    112   /// createValueName - This method attempts to create a value name and insert
    113   /// it into the symbol table with the specified name.  If it conflicts, it
    114   /// auto-renames the name and returns that instead.
    115   ValueName *createValueName(StringRef Name, Value *V);
    116 
    117   /// This method removes a value from the symbol table.  It leaves the
    118   /// ValueName attached to the value, but it is no longer inserted in the
    119   /// symtab.
    120   void removeValueName(ValueName *V);
    121 
    122   /// @}
    123   /// @name Internal Data
    124   /// @{
    125 private:
    126   ValueMap vmap;                    ///< The map that holds the symbol table.
    127   mutable uint32_t LastUnique; ///< Counter for tracking unique names
    128 
    129 /// @}
    130 };
    131 
    132 } // End llvm namespace
    133 
    134 #endif
    135