StringTableBuilder.h revision 355940 
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
18namespace llvm {
19
20class raw_ostream;
21
22/// Utility for building string tables with deduplicated suffixes.
23class StringTableBuilder {
24public:
25  enum Kind { ELF, WinCOFF, MachO, RAW, DWARF };
26
27private:
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
37public:
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
68private:
69  bool isFinalized() const { return Finalized; }
70};
71
72} // end namespace llvm
73
74#endif // LLVM_MC_STRINGTABLEBUILDER_H
75