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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/ADT/StringRef.h"
     19 #include "llvm/IR/Value.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 <unsigned InternalLen> class SmallString;
     32 template <typename ValueSubClass> 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>;
     46   friend class Value;
     47 
     48 /// @name Types
     49 /// @{
     50 public:
     51   /// @brief A mapping of names to values.
     52   using ValueMap = StringMap<Value*>;
     53 
     54   /// @brief An iterator over a ValueMap.
     55   using iterator = ValueMap::iterator;
     56 
     57   /// @brief A const_iterator over a ValueMap.
     58   using const_iterator = ValueMap::const_iterator;
     59 
     60 /// @}
     61 /// @name Constructors
     62 /// @{
     63 
     64   ValueSymbolTable() : vmap(0) {}
     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   /// @brief Lookup a named Value.
     75   Value *lookup(StringRef Name) const { return vmap.lookup(Name); }
     76 
     77   /// @returns true iff the symbol table is empty
     78   /// @brief Determine if the symbol table is empty
     79   inline bool empty() const { return vmap.empty(); }
     80 
     81   /// @brief The number of name/type pairs is returned.
     82   inline unsigned size() const { return unsigned(vmap.size()); }
     83 
     84   /// This function can be used from the debugger to display the
     85   /// content of the symbol table while debugging.
     86   /// @brief Print out symbol table on stderr
     87   void dump() const;
     88 
     89 /// @}
     90 /// @name Iteration
     91 /// @{
     92 
     93   /// @brief Get an iterator that from the beginning of the symbol table.
     94   inline iterator begin() { return vmap.begin(); }
     95 
     96   /// @brief Get a const_iterator that from the beginning of the symbol table.
     97   inline const_iterator begin() const { return vmap.begin(); }
     98 
     99   /// @brief Get an iterator to the end of the symbol table.
    100   inline iterator end() { return vmap.end(); }
    101 
    102   /// @brief Get a const_iterator to the end of the symbol table.
    103   inline const_iterator end() const { return vmap.end(); }
    104 
    105   /// @}
    106   /// @name Mutators
    107   /// @{
    108 private:
    109   ValueName *makeUniqueName(Value *V, SmallString<256> &UniqueName);
    110 
    111   /// This method adds the provided value \p N to the symbol table.  The Value
    112   /// must have a name which is used to place the value in the symbol table.
    113   /// If the inserted name conflicts, this renames the value.
    114   /// @brief Add a named value to the symbol table
    115   void reinsertValue(Value *V);
    116 
    117   /// createValueName - This method attempts to create a value name and insert
    118   /// it into the symbol table with the specified name.  If it conflicts, it
    119   /// auto-renames the name and returns that instead.
    120   ValueName *createValueName(StringRef Name, Value *V);
    121 
    122   /// This method removes a value from the symbol table.  It leaves the
    123   /// ValueName attached to the value, but it is no longer inserted in the
    124   /// symtab.
    125   void removeValueName(ValueName *V);
    126 
    127   /// @}
    128   /// @name Internal Data
    129   /// @{
    130 
    131   ValueMap vmap;                    ///< The map that holds the symbol table.
    132   mutable uint32_t LastUnique = 0;  ///< Counter for tracking unique names
    133 
    134 /// @}
    135 };
    136 
    137 } // end namespace llvm
    138 
    139 #endif // LLVM_IR_VALUESYMBOLTABLE_H
    140