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//===-- IntelPTSingleBufferTrace.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 liblldb_IntelPTSingleBufferTrace_H_
#define liblldb_IntelPTSingleBufferTrace_H_
#include "Perf.h"
#include "lldb/Utility/TraceIntelPTGDBRemotePackets.h"
#include "lldb/lldb-types.h"
#include "llvm/Support/Error.h"
#include <memory>
namespace lldb_private {
namespace process_linux {
llvm::Expected<uint32_t> GetIntelPTOSEventType();
/// This class wraps a single perf event collecting intel pt data in a single
/// buffer.
class IntelPTSingleBufferTrace {
public:
/// Start tracing using a single Intel PT trace buffer.
///
/// \param[in] request
/// Intel PT configuration parameters.
///
/// \param[in] tid
/// The tid of the thread to be traced. If \b None, then this traces all
/// threads of all processes.
///
/// \param[in] cpu_id
/// The CPU core id where to trace. If \b None, then this traces all CPUs.
///
/// \param[in] disabled
/// If \b true, then no data is collected until \a Resume is invoked.
/// Similarly, if \b false, data is collected right away until \a Pause is
/// invoked.
///
/// \param[in] cgroup_fd
/// A file descriptor in /sys/fs associated with the cgroup of the process
/// to trace. If not \a std::nullopt, then the trace sesion will use cgroup
/// filtering.
///
/// \return
/// A \a IntelPTSingleBufferTrace instance if tracing was successful, or
/// an \a llvm::Error otherwise.
static llvm::Expected<IntelPTSingleBufferTrace>
Start(const TraceIntelPTStartRequest &request, std::optional<lldb::tid_t> tid,
std::optional<lldb::cpu_id_t> cpu_id = std::nullopt,
bool disabled = false, std::optional<int> cgroup_fd = std::nullopt);
/// \return
/// The bytes requested by a jLLDBTraceGetBinaryData packet that was routed
/// to this trace instace.
llvm::Expected<std::vector<uint8_t>>
GetBinaryData(const TraceGetBinaryDataRequest &request) const;
/// Read the intel pt trace buffer managed by this trace instance. To ensure
/// that the data is up-to-date and is not corrupted by read-write race
/// conditions, the underlying perf_event is paused during read, and later
/// it's returned to its initial state.
///
/// \return
/// A vector with the requested binary data.
llvm::Expected<std::vector<uint8_t>> GetIptTrace();
/// \return
/// The total the size in bytes used by the intel pt trace buffer managed
/// by this trace instance.
size_t GetIptTraceSize() const;
/// Resume the collection of this trace.
///
/// \return
/// An error if the trace couldn't be resumed. If the trace is already
/// running, this returns \a Error::success().
llvm::Error Resume();
/// Pause the collection of this trace.
///
/// \return
/// An error if the trace couldn't be paused. If the trace is already
/// paused, this returns \a Error::success().
llvm::Error Pause();
/// \return
/// The underlying PerfEvent for this trace.
const PerfEvent &GetPerfEvent() const;
private:
/// Construct new \a IntelPTSingleBufferThreadTrace. Users are supposed to
/// create instances of this class via the \a Start() method and not invoke
/// this one directly.
///
/// \param[in] perf_event
/// perf event configured for IntelPT.
///
/// \param[in] collection_state
/// The initial collection state for the provided perf_event.
IntelPTSingleBufferTrace(PerfEvent &&perf_event)
: m_perf_event(std::move(perf_event)) {}
/// perf event configured for IntelPT.
PerfEvent m_perf_event;
};
} // namespace process_linux
} // namespace lldb_private
#endif // liblldb_IntelPTSingleBufferTrace_H_
|
