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llvm-mirror/include/llvm/Remarks/BitstreamRemarkParser.h
Francis Visoiu Mistrih c0b919738c [Remarks] Add parser for bitstream remarks
The bitstream remark serializer landed in r367372.

This adds a bitstream remark parser that parser bitstream remark files
to llvm::remarks::Remark objects through the RemarkParser interface.

A few interesting things to point out:

* There are parsing helpers to parse the different types of blocks
* The main parsing helper allows us to parse remark metadata and open an
external file containing the encoded remarks
* This adds a dependency from the Remarks library to the BitstreamReader
library
* The testing strategy is to create a remark entry through YAML, parse
it, serialize it to bitstream, parse that back and compare the objects.
* There are close to no tests for malformed bitstream remarks, due to
the lack of textual format for the bitstream format.
* This adds a new C API for parsing bitstream remarks:
LLVMRemarkParserCreateBitstream.
* This bumps the REMARKS_API_VERSION to 1.

Differential Revision: https://reviews.llvm.org/D67134

llvm-svn: 371429
2019-09-09 17:43:50 +00:00

117 lines
4.2 KiB
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//===-- BitstreamRemarkParser.h - Bitstream parser --------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file provides an implementation of the remark parser using the LLVM
// Bitstream format.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_REMARKS_BITSTREAM_REMARK_PARSER_H
#define LLVM_REMARKS_BITSTREAM_REMARK_PARSER_H
#include "llvm/ADT/StringRef.h"
#include "llvm/Bitstream/BitstreamReader.h"
#include "llvm/Remarks/BitstreamRemarkContainer.h"
#include "llvm/Remarks/Remark.h"
#include "llvm/Remarks/RemarkParser.h"
#include "llvm/Support/Error.h"
#include <array>
namespace llvm {
namespace remarks {
/// Helper to parse a META_BLOCK for a bitstream remark container.
struct BitstreamMetaParserHelper {
/// The Bitstream reader.
BitstreamCursor &Stream;
/// Reference to the storage for the block info.
BitstreamBlockInfo &BlockInfo;
/// The parsed content: depending on the container type, some fields might be
/// empty.
Optional<uint64_t> ContainerVersion;
Optional<uint8_t> ContainerType;
Optional<StringRef> StrTabBuf;
Optional<StringRef> ExternalFilePath;
Optional<uint64_t> RemarkVersion;
/// Continue parsing with \p Stream. \p Stream is expected to contain a
/// ENTER_SUBBLOCK to the META_BLOCK at the current position.
/// \p Stream is expected to have a BLOCKINFO_BLOCK set.
BitstreamMetaParserHelper(BitstreamCursor &Stream,
BitstreamBlockInfo &BlockInfo);
/// Parse the META_BLOCK and fill the available entries.
/// This helper does not check for the validity of the fields.
Error parse();
};
/// Helper to parse a REMARK_BLOCK for a bitstream remark container.
struct BitstreamRemarkParserHelper {
/// The Bitstream reader.
BitstreamCursor &Stream;
/// The parsed content: depending on the remark, some fields might be empty.
Optional<uint8_t> Type;
Optional<uint64_t> RemarkNameIdx;
Optional<uint64_t> PassNameIdx;
Optional<uint64_t> FunctionNameIdx;
Optional<uint64_t> SourceFileNameIdx;
Optional<uint32_t> SourceLine;
Optional<uint32_t> SourceColumn;
Optional<uint64_t> Hotness;
struct Argument {
Optional<uint64_t> KeyIdx;
Optional<uint64_t> ValueIdx;
Optional<uint64_t> SourceFileNameIdx;
Optional<uint32_t> SourceLine;
Optional<uint32_t> SourceColumn;
};
Optional<ArrayRef<Argument>> Args;
/// Avoid re-allocating a vector every time.
SmallVector<Argument, 8> TmpArgs;
/// Continue parsing with \p Stream. \p Stream is expected to contain a
/// ENTER_SUBBLOCK to the REMARK_BLOCK at the current position.
/// \p Stream is expected to have a BLOCKINFO_BLOCK set and to have already
/// parsed the META_BLOCK.
BitstreamRemarkParserHelper(BitstreamCursor &Stream);
/// Parse the REMARK_BLOCK and fill the available entries.
/// This helper does not check for the validity of the fields.
Error parse();
};
/// Helper to parse any bitstream remark container.
struct BitstreamParserHelper {
/// The Bitstream reader.
BitstreamCursor Stream;
/// The block info block.
BitstreamBlockInfo BlockInfo;
/// Start parsing at \p Buffer.
BitstreamParserHelper(StringRef Buffer);
/// Parse the magic number.
Expected<std::array<char, 4>> parseMagic();
/// Parse the block info block containing all the abbrevs.
/// This needs to be called before calling any other parsing function.
Error parseBlockInfoBlock();
/// Return true if the next block is a META_BLOCK. This function does not move
/// the cursor.
Expected<bool> isMetaBlock();
/// Return true if the next block is a REMARK_BLOCK. This function does not
/// move the cursor.
Expected<bool> isRemarkBlock();
/// Return true if the parser reached the end of the stream.
bool atEndOfStream() { return Stream.AtEndOfStream(); }
/// Jump to the end of the stream, skipping everything.
void skipToEnd() { return Stream.skipToEnd(); }
};
} // end namespace remarks
} // end namespace llvm
#endif /* LLVM_REMARKS_BITSTREAM_REMARK_PARSER_H */