clang-tools  10.0.0svn
BitcodeWriter.h
Go to the documentation of this file.
1 //===-- BitcodeWriter.h - ClangDoc Bitcode Writer --------------*- 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 // This file implements a writer for serializing the clang-doc internal
10 // representation to LLVM bitcode. The writer takes in a stream and emits the
11 // generated bitcode to that stream.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEWRITER_H
16 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEWRITER_H
17 
18 #include "Representation.h"
19 #include "clang/AST/AST.h"
20 #include "llvm/ADT/DenseMap.h"
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/ADT/StringRef.h"
23 #include "llvm/Bitstream/BitstreamWriter.h"
24 #include <initializer_list>
25 #include <vector>
26 
27 namespace clang {
28 namespace doc {
29 
30 // Current version number of clang-doc bitcode.
31 // Should be bumped when removing or changing BlockIds, RecordIds, or
32 // BitCodeConstants, though they can be added without breaking it.
33 static const unsigned VersionNumber = 3;
34 
36  static constexpr unsigned RecordSize = 32U;
37  static constexpr unsigned SignatureBitSize = 8U;
38  static constexpr unsigned SubblockIDSize = 4U;
39  static constexpr unsigned BoolSize = 1U;
40  static constexpr unsigned IntSize = 16U;
41  static constexpr unsigned StringLengthSize = 16U;
42  static constexpr unsigned FilenameLengthSize = 16U;
43  static constexpr unsigned LineNumberSize = 32U;
44  static constexpr unsigned ReferenceTypeSize = 8U;
45  static constexpr unsigned USRLengthSize = 6U;
46  static constexpr unsigned USRBitLengthSize = 8U;
47  static constexpr unsigned char Signature[4] = {'D', 'O', 'C', 'S'};
48  static constexpr int USRHashSize = 20;
49 };
50 
51 // New Ids need to be added to both the enum here and the relevant IdNameMap in
52 // the implementation file.
53 enum BlockId {
54  BI_VERSION_BLOCK_ID = llvm::bitc::FIRST_APPLICATION_BLOCKID,
67 };
68 
69 // New Ids need to be added to the enum here, and to the relevant IdNameMap and
70 // initialization list in the implementation file.
71 enum RecordId {
72  VERSION = 1,
124 };
125 
126 static constexpr unsigned BlockIdCount = BI_LAST - BI_FIRST;
127 static constexpr unsigned RecordIdCount = RI_LAST - RI_FIRST;
128 
129 // Identifiers for differentiating between subblocks
130 enum class FieldId {
131  F_default,
132  F_namespace,
133  F_parent,
134  F_vparent,
135  F_type,
138 };
139 
141 public:
142  ClangDocBitcodeWriter(llvm::BitstreamWriter &Stream) : Stream(Stream) {
143  emitHeader();
144  emitBlockInfoBlock();
145  emitVersionBlock();
146  }
147 
148  // Write a specific info to a bitcode stream.
149  bool dispatchInfoForWrite(Info *I);
150 
151  // Block emission of different info types.
152  void emitBlock(const NamespaceInfo &I);
153  void emitBlock(const RecordInfo &I);
154  void emitBlock(const BaseRecordInfo &I);
155  void emitBlock(const FunctionInfo &I);
156  void emitBlock(const EnumInfo &I);
157  void emitBlock(const TypeInfo &B);
158  void emitBlock(const FieldTypeInfo &B);
159  void emitBlock(const MemberTypeInfo &B);
160  void emitBlock(const CommentInfo &B);
161  void emitBlock(const Reference &B, FieldId F);
162 
163 private:
164  class AbbreviationMap {
165  llvm::DenseMap<unsigned, unsigned> Abbrevs;
166 
167  public:
168  AbbreviationMap() : Abbrevs(RecordIdCount) {}
169 
170  void add(RecordId RID, unsigned AbbrevID);
171  unsigned get(RecordId RID) const;
172  };
173 
174  class StreamSubBlockGuard {
175  llvm::BitstreamWriter &Stream;
176 
177  public:
178  StreamSubBlockGuard(llvm::BitstreamWriter &Stream_, BlockId ID)
179  : Stream(Stream_) {
180  // NOTE: SubBlockIDSize could theoretically be calculated on the fly,
181  // based on the initialization list of records in each block.
182  Stream.EnterSubblock(ID, BitCodeConstants::SubblockIDSize);
183  }
184 
185  StreamSubBlockGuard(const StreamSubBlockGuard &) = delete;
186  StreamSubBlockGuard &operator=(const StreamSubBlockGuard &) = delete;
187 
188  ~StreamSubBlockGuard() { Stream.ExitBlock(); }
189  };
190 
191  // Emission of validation and overview blocks.
192  void emitHeader();
193  void emitVersionBlock();
194  void emitRecordID(RecordId ID);
195  void emitBlockID(BlockId ID);
196  void emitBlockInfoBlock();
197  void emitBlockInfo(BlockId BID, const std::vector<RecordId> &RIDs);
198 
199  // Emission of individual record types.
200  void emitRecord(StringRef Str, RecordId ID);
201  void emitRecord(const SymbolID &Str, RecordId ID);
202  void emitRecord(const Location &Loc, RecordId ID);
203  void emitRecord(const Reference &Ref, RecordId ID);
204  void emitRecord(bool Value, RecordId ID);
205  void emitRecord(int Value, RecordId ID);
206  void emitRecord(unsigned Value, RecordId ID);
207  bool prepRecordData(RecordId ID, bool ShouldEmit = true);
208 
209  // Emission of appropriate abbreviation type.
210  void emitAbbrev(RecordId ID, BlockId Block);
211 
212  // Static size is the maximum length of the block/record names we're pushing
213  // to this + 1. Longest is currently `MemberTypeBlock` at 15 chars.
214  SmallVector<uint32_t, BitCodeConstants::RecordSize> Record;
215  llvm::BitstreamWriter &Stream;
216  AbbreviationMap Abbrevs;
217 };
218 
219 } // namespace doc
220 } // namespace clang
221 
222 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEWRITER_H
SourceLocation Loc
&#39;#&#39; location in the include directive
static constexpr unsigned SignatureBitSize
Definition: BitcodeWriter.h:37
static const unsigned VersionNumber
Definition: BitcodeWriter.h:33
static constexpr unsigned SubblockIDSize
Definition: BitcodeWriter.h:38
static constexpr unsigned BlockIdCount
static constexpr unsigned char Signature[4]
Definition: BitcodeWriter.h:47
ClangDocBitcodeWriter(llvm::BitstreamWriter &Stream)
llvm::SmallVector< uint64_t, 1024 > Record
static constexpr unsigned BoolSize
Definition: BitcodeWriter.h:39
static constexpr unsigned LineNumberSize
Definition: BitcodeWriter.h:43
static constexpr unsigned RecordSize
Definition: BitcodeWriter.h:36
static constexpr int USRHashSize
Definition: BitcodeWriter.h:48
static constexpr unsigned ReferenceTypeSize
Definition: BitcodeWriter.h:44
A base struct for Infos.
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
static constexpr unsigned IntSize
Definition: BitcodeWriter.h:40
static constexpr unsigned USRBitLengthSize
Definition: BitcodeWriter.h:46
static constexpr unsigned USRLengthSize
Definition: BitcodeWriter.h:45
static constexpr unsigned StringLengthSize
Definition: BitcodeWriter.h:41
std::array< uint8_t, 20 > SymbolID
static constexpr unsigned FilenameLengthSize
Definition: BitcodeWriter.h:42
static constexpr unsigned RecordIdCount