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//===-- DecodedThread.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_INTEL_PT_DECODEDTHREAD_H
#define LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_DECODEDTHREAD_H
#include <vector>
#include "llvm/Support/Errc.h"
#include "llvm/Support/Error.h"
#include "lldb/Target/Trace.h"
#include "intel-pt.h"
namespace lldb_private {
namespace trace_intel_pt {
/// Class for representing a libipt decoding error.
class IntelPTError : public llvm::ErrorInfo<IntelPTError> {
public:
static char ID;
/// \param[in] libipt_error_code
/// Negative number returned by libipt when decoding the trace and
/// signaling errors.
///
/// \param[in] address
/// Optional instruction address. When decoding an individual instruction,
/// its address might be available in the \a pt_insn object, and should be
/// passed to this constructor. Other errors don't have an associated
/// address.
IntelPTError(int libipt_error_code,
lldb::addr_t address = LLDB_INVALID_ADDRESS);
std::error_code convertToErrorCode() const override {
return llvm::errc::not_supported;
}
void log(llvm::raw_ostream &OS) const override;
private:
int m_libipt_error_code;
lldb::addr_t m_address;
};
/// \class IntelPTInstruction
/// An instruction obtained from decoding a trace. It is either an actual
/// instruction or an error indicating a gap in the trace.
///
/// Gaps in the trace can come in a few flavors:
/// - tracing gaps (e.g. tracing was paused and then resumed)
/// - tracing errors (e.g. buffer overflow)
/// - decoding errors (e.g. some memory region couldn't be decoded)
/// As mentioned, any gap is represented as an error in this class.
class IntelPTInstruction {
public:
IntelPTInstruction(const pt_insn &pt_insn) : m_pt_insn(pt_insn) {}
/// Error constructor
///
/// libipt errors should use the underlying \a IntelPTError class.
IntelPTInstruction(llvm::Error err) {
llvm::handleAllErrors(std::move(err),
[&](std::unique_ptr<llvm::ErrorInfoBase> info) {
m_error = std::move(info);
});
}
/// Check if this object represents an error (i.e. a gap).
///
/// \return
/// Whether this object represents an error.
bool IsError() const;
/// \return
/// The instruction pointer address, or an \a llvm::Error if it is an
/// error.
llvm::Expected<lldb::addr_t> GetLoadAddress() const;
/// \return
/// An \a llvm::Error object if this class corresponds to an Error, or an
/// \a llvm::Error::success otherwise.
llvm::Error ToError() const;
IntelPTInstruction(IntelPTInstruction &&other) = default;
private:
IntelPTInstruction(const IntelPTInstruction &other) = delete;
const IntelPTInstruction &operator=(const IntelPTInstruction &other) = delete;
pt_insn m_pt_insn;
std::unique_ptr<llvm::ErrorInfoBase> m_error;
};
/// \class DecodedThread
/// Class holding the instructions and function call hierarchy obtained from
/// decoding a trace, as well as a position cursor used when reverse debugging
/// the trace.
///
/// Each decoded thread contains a cursor to the current position the user is
/// stopped at. See \a Trace::GetCursorPosition for more information.
class DecodedThread {
public:
DecodedThread(std::vector<IntelPTInstruction> &&instructions)
: m_instructions(std::move(instructions)), m_position(GetLastPosition()) {
}
/// Get the instructions from the decoded trace. Some of them might indicate
/// errors (i.e. gaps) in the trace.
///
/// \return
/// The instructions of the trace.
llvm::ArrayRef<IntelPTInstruction> GetInstructions() const;
/// \return
/// The current position of the cursor of this trace, or 0 if there are no
/// instructions.
size_t GetCursorPosition() const;
/// Change the position of the cursor of this trace. If this value is to high,
/// the new position will be set as the last instruction of the trace.
///
/// \return
/// The effective new position.
size_t SetCursorPosition(size_t new_position);
/// \}
private:
/// \return
/// The index of the last element of the trace, or 0 if empty.
size_t GetLastPosition() const;
std::vector<IntelPTInstruction> m_instructions;
size_t m_position;
};
} // namespace trace_intel_pt
} // namespace lldb_private
#endif // LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_DECODEDTHREAD_H