src/llvm/include/llvm/MC/StringTableBuilder.h

   1 //===-- StringTableBuilder.h - String table building utility ------*- 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 #ifndef LLVM_MC_STRINGTABLEBUILDER_H
  11 #define LLVM_MC_STRINGTABLEBUILDER_H
  12
  13 #include "llvm/ADT/SmallString.h"
  14 #include "llvm/ADT/StringMap.h"
  15 #include <cassert>
  16
  17 namespace llvm {
  18
  19 /// \brief Utility for building string tables with deduplicated suffixes.
  20 class StringTableBuilder {
  21   SmallString<256> StringTable;
  22   StringMap<size_t> StringIndexMap;
  23
  24 public:
  25   /// \brief Add a string to the builder. Returns a StringRef to the internal
  26   /// copy of s. Can only be used before the table is finalized.
  27   StringRef add(StringRef s) {
  28     assert(!isFinalized());
  29     return StringIndexMap.insert(std::make_pair(s, 0)).first->first();
  30   }
  31
  32   enum Kind {
  33     ELF,
  34     WinCOFF,
  35     MachO
  36   };
  37
  38   /// \brief Analyze the strings and build the final table. No more strings can
  39   /// be added after this point.
  40   void finalize(Kind kind);
  41
  42   /// \brief Retrieve the string table data. Can only be used after the table
  43   /// is finalized.
  44   StringRef data() {
  45     assert(isFinalized());
  46     return StringTable;
  47   }
  48
  49   /// \brief Get the offest of a string in the string table. Can only be used
  50   /// after the table is finalized.
  51   size_t getOffset(StringRef s) {
  52     assert(isFinalized());
  53     assert(StringIndexMap.count(s) && "String is not in table!");
  54     return StringIndexMap[s];
  55   }
  56
  57   void clear();
  58
  59 private:
  60   bool isFinalized() {
  61     return !StringTable.empty();
  62   }
  63 };
  64
  65 } // end llvm namespace
  66
  67 #endif