| //===-- SBTraceCursor.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_API_SBTRACECURSOR_H |
| #define LLDB_API_SBTRACECURSOR_H |
| |
| #include "lldb/API/SBDefines.h" |
| #include "lldb/API/SBError.h" |
| #include "lldb/API/SBExecutionContext.h" |
| |
| namespace lldb { |
| |
| class LLDB_API SBTraceCursor { |
| public: |
| /// Default constructor for an invalid \a SBTraceCursor object. |
| SBTraceCursor(); |
| |
| /// Set the direction to use in the \a SBTraceCursor::Next() method. |
| /// |
| /// \param[in] forwards |
| /// If \b true, then the traversal will be forwards, otherwise backwards. |
| void SetForwards(bool forwards); |
| |
| /// Check if the direction to use in the \a SBTraceCursor::Next() method is |
| /// forwards. |
| /// |
| /// \return |
| /// \b true if the current direction is forwards, \b false if backwards. |
| bool IsForwards() const; |
| |
| /// Move the cursor to the next item (instruction or error). |
| /// |
| /// Direction: |
| /// The traversal is done following the current direction of the trace. If |
| /// it is forwards, the instructions are visited forwards |
| /// chronologically. Otherwise, the traversal is done in |
| /// the opposite direction. By default, a cursor moves backwards unless |
| /// changed with \a SBTraceCursor::SetForwards(). |
| void Next(); |
| |
| /// \return |
| /// \b true if the cursor is pointing to a valid item. \b false if the |
| /// cursor has reached the end of the trace. |
| bool HasValue() const; |
| |
| /// Instruction identifiers: |
| /// |
| /// When building complex higher level tools, fast random accesses in the |
| /// trace might be needed, for which each instruction requires a unique |
| /// identifier within its thread trace. For example, a tool might want to |
| /// repeatedly inspect random consecutive portions of a trace. This means that |
| /// it will need to first move quickly to the beginning of each section and |
| /// then start its iteration. Given that the number of instructions can be in |
| /// the order of hundreds of millions, fast random access is necessary. |
| /// |
| /// An example of such a tool could be an inspector of the call graph of a |
| /// trace, where each call is represented with its start and end instructions. |
| /// Inspecting all the instructions of a call requires moving to its first |
| /// instruction and then iterating until the last instruction, which following |
| /// the pattern explained above. |
| /// |
| /// Instead of using 0-based indices as identifiers, each Trace plug-in can |
| /// decide the nature of these identifiers and thus no assumptions can be made |
| /// regarding their ordering and sequentiality. The reason is that an |
| /// instruction might be encoded by the plug-in in a way that hides its actual |
| /// 0-based index in the trace, but it's still possible to efficiently find |
| /// it. |
| /// |
| /// Requirements: |
| /// - For a given thread, no two instructions have the same id. |
| /// - In terms of efficiency, moving the cursor to a given id should be as |
| /// fast as possible, but not necessarily O(1). That's why the recommended |
| /// way to traverse sequential instructions is to use the \a |
| /// SBTraceCursor::Next() method and only use \a SBTraceCursor::GoToId(id) |
| /// sparingly. |
| |
| /// Make the cursor point to the item whose identifier is \p id. |
| /// |
| /// \return |
| /// \b true if the given identifier exists and the cursor effectively |
| /// moved to it. Otherwise, \b false is returned and the cursor now points |
| /// to an invalid item, i.e. calling \a HasValue() will return \b false. |
| bool GoToId(lldb::user_id_t id); |
| |
| /// \return |
| /// \b true if and only if there's an instruction item with the given \p |
| /// id. |
| bool HasId(lldb::user_id_t id) const; |
| |
| /// \return |
| /// A unique identifier for the instruction or error this cursor is |
| /// pointing to. |
| lldb::user_id_t GetId() const; |
| /// \} |
| |
| /// Make the cursor point to an item in the trace based on an origin point and |
| /// an offset. |
| /// |
| /// The resulting position of the trace is |
| /// origin + offset |
| /// |
| /// If this resulting position would be out of bounds, the trace then points |
| /// to an invalid item, i.e. calling \a HasValue() returns \b false. |
| /// |
| /// \param[in] offset |
| /// How many items to move forwards (if positive) or backwards (if |
| /// negative) from the given origin point. For example, if origin is \b |
| /// End, then a negative offset would move backward in the trace, but a |
| /// positive offset would move past the trace to an invalid item. |
| /// |
| /// \param[in] origin |
| /// The reference point to use when moving the cursor. |
| /// |
| /// \return |
| /// \b true if and only if the cursor ends up pointing to a valid item. |
| bool Seek(int64_t offset, lldb::TraceCursorSeekType origin); |
| |
| /// Trace item information (instructions, errors and events) |
| /// \{ |
| |
| /// \return |
| /// The kind of item the cursor is pointing at. |
| lldb::TraceItemKind GetItemKind() const; |
| |
| /// \return |
| /// Whether the cursor points to an error or not. |
| bool IsError() const; |
| |
| /// \return |
| /// The error message the cursor is pointing at. |
| const char *GetError() const; |
| |
| /// \return |
| /// Whether the cursor points to an event or not. |
| bool IsEvent() const; |
| |
| /// \return |
| /// The specific kind of event the cursor is pointing at. |
| lldb::TraceEvent GetEventType() const; |
| |
| /// \return |
| /// A human-readable description of the event this cursor is pointing at. |
| const char *GetEventTypeAsString() const; |
| |
| /// \return |
| /// Whether the cursor points to an instruction. |
| bool IsInstruction() const; |
| |
| /// \return |
| /// The load address of the instruction the cursor is pointing at. |
| lldb::addr_t GetLoadAddress() const; |
| |
| /// \return |
| /// The requested CPU id, or LLDB_INVALID_CPU_ID if this information is |
| /// not available for the current item. |
| lldb::cpu_id_t GetCPU() const; |
| |
| bool IsValid() const; |
| |
| explicit operator bool() const; |
| |
| protected: |
| friend class SBTrace; |
| |
| /// Create a cursor that initially points to the end of the trace, i.e. the |
| /// most recent item. |
| SBTraceCursor(lldb::TraceCursorSP trace_cursor_sp); |
| |
| lldb::TraceCursorSP m_opaque_sp; |
| }; |
| } // namespace lldb |
| |
| #endif // LLDB_API_SBTRACECURSOR_H |