Files
clang-p2996/lldb/source/Plugins/Trace/intel-pt/ThreadDecoder.h
Walter Erquinigo a7d6c3effe [trace] Make events first class items in the trace cursor and rework errors
We want to include events with metadata, like context switches, and this
requires the API to handle events with payloads (e.g. information about
such context switches). Besides this, we want to support multiple
similar events between two consecutive instructions, like multiple
context switches. However, the current implementation is not good for this because
we are defining events as bitmask enums associated with specific
instructions. Thus, we need to decouple instructions from events and
make events actual items in the trace, just like instructions and
errors.

- Add accessors in the TraceCursor to know if an item is an event or not
- Modify from the TraceDumper all the way to DecodedThread to support
- Renamed the paused event to disabled.
- Improved the tsc handling logic. I was using an API for getting the tsc from libipt, but that was an overkill that should be used when not processing events manually, but as we are already processing events, we can more easily get the tscs.
event items. Fortunately this simplified many things
- As part of this refactor, I also fixed and long stating issue, which is that some non decoding errors were being inserted in the decoded thread. I changed this so that TraceIntelPT::Decode returns an error if the decoder couldn't be set up proplerly. Then, errors within a trace are actual anomalies found in between instrutions.

All test pass

Differential Revision: https://reviews.llvm.org/D128576
2022-06-29 09:19:51 -07:00

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1.6 KiB
C++

//===-- ThreadDecoder.h --======---------------------------------*- 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
//
//===----------------------------------------------------------------------===//
#ifndef LLDB_SOURCE_PLUGINS_TRACE_THREAD_DECODER_H
#define LLDB_SOURCE_PLUGINS_TRACE_THREAD_DECODER_H
#include "intel-pt.h"
#include "DecodedThread.h"
#include "forward-declarations.h"
#include "lldb/Target/Process.h"
#include "lldb/Utility/FileSpec.h"
namespace lldb_private {
namespace trace_intel_pt {
/// Class that handles the decoding of a thread and caches the result.
class ThreadDecoder {
public:
/// \param[in] thread_sp
/// The thread whose intel pt trace buffer will be decoded.
///
/// \param[in] trace
/// The main Trace object who owns this decoder and its data.
ThreadDecoder(const lldb::ThreadSP &thread_sp, TraceIntelPT &trace);
/// Decode the thread and store the result internally, to avoid
/// recomputations.
///
/// \return
/// A \a DecodedThread instance.
llvm::Expected<DecodedThreadSP> Decode();
ThreadDecoder(const ThreadDecoder &other) = delete;
ThreadDecoder &operator=(const ThreadDecoder &other) = delete;
private:
llvm::Expected<DecodedThreadSP> DoDecode();
lldb::ThreadSP m_thread_sp;
TraceIntelPT &m_trace;
llvm::Optional<DecodedThreadSP> m_decoded_thread;
};
} // namespace trace_intel_pt
} // namespace lldb_private
#endif // LLDB_SOURCE_PLUGINS_TRACE_THREAD_DECODER_H