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       1             : //===--  BitcodeReader.h - ClangDoc Bitcode Reader --------------*- 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             : // This file implements a reader for parsing the clang-doc internal
      11             : // representation from LLVM bitcode. The reader takes in a stream of bits and
      12             : // generates the set of infos that it represents.
      13             : //
      14             : //===----------------------------------------------------------------------===//
      15             : 
      16             : #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEREADER_H
      17             : #define LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEREADER_H
      18             : 
      19             : #include "BitcodeWriter.h"
      20             : #include "Representation.h"
      21             : #include "clang/AST/AST.h"
      22             : #include "llvm/ADT/Optional.h"
      23             : #include "llvm/ADT/SmallVector.h"
      24             : #include "llvm/Bitcode/BitstreamReader.h"
      25             : #include "llvm/Support/Error.h"
      26             : 
      27             : namespace clang {
      28             : namespace doc {
      29             : 
      30             : // Class to read bitstream into an InfoSet collection
      31           6 : class ClangDocBitcodeReader {
      32             : public:
      33           6 :   ClangDocBitcodeReader(llvm::BitstreamCursor &Stream) : Stream(Stream) {}
      34             : 
      35             :   // Main entry point, calls readBlock to read each block in the given stream.
      36             :   llvm::Expected<std::vector<std::unique_ptr<Info>>> readBitcode();
      37             : 
      38             : private:
      39             :   enum class Cursor { BadBlock = 1, Record, BlockEnd, BlockBegin };
      40             : 
      41             :   // Top level parsing
      42             :   llvm::Error validateStream();
      43             :   llvm::Error readVersion();
      44             :   llvm::Error readBlockInfoBlock();
      45             : 
      46             :   // Read a block of records into a single Info struct, calls readRecord on each
      47             :   // record found.
      48             :   template <typename T> llvm::Error readBlock(unsigned ID, T I);
      49             : 
      50             :   // Step through a block of records to find the next data field.
      51             :   template <typename T> llvm::Error readSubBlock(unsigned ID, T I);
      52             : 
      53             :   // Read record data into the given Info data field, calling the appropriate
      54             :   // parseRecord functions to parse and store the data.
      55             :   template <typename T> llvm::Error readRecord(unsigned ID, T I);
      56             : 
      57             :   // Allocate the relevant type of info and add read data to the object.
      58             :   template <typename T>
      59             :   llvm::Expected<std::unique_ptr<Info>> createInfo(unsigned ID);
      60             : 
      61             :   // Helper function to step through blocks to find and dispatch the next record
      62             :   // or block to be read.
      63             :   Cursor skipUntilRecordOrBlock(unsigned &BlockOrRecordID);
      64             : 
      65             :   // Helper function to set up the approriate type of Info.
      66             :   llvm::Expected<std::unique_ptr<Info>> readBlockToInfo(unsigned ID);
      67             : 
      68             :   llvm::BitstreamCursor &Stream;
      69             :   Optional<llvm::BitstreamBlockInfo> BlockInfo;
      70             :   FieldId CurrentReferenceField;
      71             : };
      72             : 
      73             : } // namespace doc
      74             : } // namespace clang
      75             : 
      76             : #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_DOC_BITCODEREADER_H