include/llvm/MC/StringTableBuilder.h

   1 //===- StringTableBuilder.h - String table building utility -----*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_MC_STRINGTABLEBUILDER_H
  10 #define LLVM_MC_STRINGTABLEBUILDER_H
  11
  12 #include "llvm/ADT/CachedHashString.h"
  13 #include "llvm/ADT/DenseMap.h"
  14 #include "llvm/ADT/StringRef.h"
  15 #include <cstddef>
  16 #include <cstdint>
  17
  18 namespace llvm {
  19
  20 class raw_ostream;
  21
  22 /// Utility for building string tables with deduplicated suffixes.
  23 class StringTableBuilder {
  24 public:
  25   enum Kind { ELF, WinCOFF, MachO, RAW, DWARF, XCOFF };
  26
  27 private:
  28   DenseMap<CachedHashStringRef, size_t> StringIndexMap;
  29   size_t Size = 0;
  30   Kind K;
  31   unsigned Alignment;
  32   bool Finalized = false;
  33
  34   void finalizeStringTable(bool Optimize);
  35   void initSize();
  36
  37 public:
  38   StringTableBuilder(Kind K, unsigned Alignment = 1);
  39   ~StringTableBuilder();
  40
  41   /// Add a string to the builder. Returns the position of S in the
  42   /// table. The position will be changed if finalize is used.
  43   /// Can only be used before the table is finalized.
  44   size_t add(CachedHashStringRef S);
  45   size_t add(StringRef S) { return add(CachedHashStringRef(S)); }
  46
  47   /// Analyze the strings and build the final table. No more strings can
  48   /// be added after this point.
  49   void finalize();
  50
  51   /// Finalize the string table without reording it. In this mode, offsets
  52   /// returned by add will still be valid.
  53   void finalizeInOrder();
  54
  55   /// Get the offest of a string in the string table. Can only be used
  56   /// after the table is finalized.
  57   size_t getOffset(CachedHashStringRef S) const;
  58   size_t getOffset(StringRef S) const {
  59     return getOffset(CachedHashStringRef(S));
  60   }
  61
  62   size_t getSize() const { return Size; }
  63   void clear();
  64
  65   void write(raw_ostream &OS) const;
  66   void write(uint8_t *Buf) const;
  67
  68 private:
  69   bool isFinalized() const { return Finalized; }
  70 };
  71
  72 } // end namespace llvm
  73
  74 #endif // LLVM_MC_STRINGTABLEBUILDER_H