clang-tools  12.0.0git
BitcodeReader.h
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1 //===-- BitcodeReader.h - ClangDoc Bitcode Reader --------------*- 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 reader for parsing the clang-doc internal
10 // representation from LLVM bitcode. The reader takes in a stream of bits and
11 // generates the set of infos that it represents.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEREADER_H
16 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEREADER_H
17 
18 #include "BitcodeWriter.h"
19 #include "Representation.h"
20 #include "clang/AST/AST.h"
21 #include "llvm/ADT/Optional.h"
22 #include "llvm/ADT/SmallVector.h"
23 #include "llvm/Bitstream/BitstreamReader.h"
24 #include "llvm/Support/Error.h"
25 
26 namespace clang {
27 namespace doc {
28 
29 // Class to read bitstream into an InfoSet collection
31 public:
32  ClangDocBitcodeReader(llvm::BitstreamCursor &Stream) : Stream(Stream) {}
33 
34  // Main entry point, calls readBlock to read each block in the given stream.
35  llvm::Expected<std::vector<std::unique_ptr<Info>>> readBitcode();
36 
37 private:
38  enum class Cursor { BadBlock = 1, Record, BlockEnd, BlockBegin };
39 
40  // Top level parsing
41  llvm::Error validateStream();
42  llvm::Error readVersion();
43  llvm::Error readBlockInfoBlock();
44 
45  // Read a block of records into a single Info struct, calls readRecord on each
46  // record found.
47  template <typename T> llvm::Error readBlock(unsigned ID, T I);
48 
49  // Step through a block of records to find the next data field.
50  template <typename T> llvm::Error readSubBlock(unsigned ID, T I);
51 
52  // Read record data into the given Info data field, calling the appropriate
53  // parseRecord functions to parse and store the data.
54  template <typename T> llvm::Error readRecord(unsigned ID, T I);
55 
56  // Allocate the relevant type of info and add read data to the object.
57  template <typename T>
58  llvm::Expected<std::unique_ptr<Info>> createInfo(unsigned ID);
59 
60  // Helper function to step through blocks to find and dispatch the next record
61  // or block to be read.
62  Cursor skipUntilRecordOrBlock(unsigned &BlockOrRecordID);
63 
64  // Helper function to set up the appropriate type of Info.
65  llvm::Expected<std::unique_ptr<Info>> readBlockToInfo(unsigned ID);
66 
67  llvm::BitstreamCursor &Stream;
68  Optional<llvm::BitstreamBlockInfo> BlockInfo;
69  FieldId CurrentReferenceField;
70 };
71 
72 } // namespace doc
73 } // namespace clang
74 
75 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEREADER_H
ClangDocBitcodeReader(llvm::BitstreamCursor &Stream)
Definition: BitcodeReader.h:32
llvm::SmallVector< uint64_t, 1024 > Record
llvm::Expected< std::vector< std::unique_ptr< Info > > > readBitcode()
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//