| //===-- Trace.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_TARGET_TRACE_H |
| #define LLDB_TARGET_TRACE_H |
| |
| #include "llvm/Support/JSON.h" |
| |
| #include "lldb/Core/PluginInterface.h" |
| #include "lldb/Utility/ArchSpec.h" |
| #include "lldb/Utility/UnimplementedError.h" |
| #include "lldb/lldb-private.h" |
| |
| namespace lldb_private { |
| |
| /// \class Trace Trace.h "lldb/Target/Trace.h" |
| /// A plug-in interface definition class for trace information. |
| /// |
| /// Trace plug-ins allow processor trace information to be loaded into LLDB so |
| /// that the data can be dumped, used for reverse and forward stepping to allow |
| /// introspection into the reason your process crashed or found its way to its |
| /// current state. |
| /// |
| /// Trace information can be loaded into a target without a process to allow |
| /// introspection of the trace information during post mortem analysis, such as |
| /// when loading core files. |
| /// |
| /// Processor trace information can also be fetched through the process |
| /// interfaces during a live debug session if your process supports gathering |
| /// this information. |
| /// |
| /// In order to support live tracing, the name of the plug-in should match the |
| /// name of the tracing type returned by the gdb-remote packet |
| /// \a jLLDBTraceSupportedType. |
| class Trace : public PluginInterface, |
| public std::enable_shared_from_this<Trace> { |
| public: |
| enum class TraceDirection { |
| Forwards = 0, |
| Backwards, |
| }; |
| |
| /// Dump the trace data that this plug-in has access to. |
| /// |
| /// This function will dump all of the trace data for all threads in a user |
| /// readable format. Options for dumping can be added as this API is iterated |
| /// on. |
| /// |
| /// \param[in] s |
| /// A stream object to dump the information to. |
| virtual void Dump(Stream *s) const = 0; |
| |
| /// Find a trace plug-in using JSON data. |
| /// |
| /// When loading trace data from disk, the information for the trace data |
| /// can be contained in multiple files and require plug-in specific |
| /// information about the CPU. Using data like JSON provides an |
| /// easy way to specify all of the settings and information that we will need |
| /// to load trace data into LLDB. This structured data can include: |
| /// - The plug-in name (this allows a specific plug-in to be selected) |
| /// - Architecture or target triple |
| /// - one or more paths to the trace data file on disk |
| /// - core trace data |
| /// - thread events or related information |
| /// - shared library load information to use for this trace data that |
| /// allows a target to be created so the trace information can be |
| /// symbolicated so that the trace information can be displayed to the |
| /// user |
| /// - shared library path |
| /// - load address |
| /// - information on how to fetch the shared library |
| /// - path to locally cached file on disk |
| /// - URL to download the file |
| /// - Any information needed to load the trace file |
| /// - CPU information |
| /// - Custom plug-in information needed to decode the trace information |
| /// correctly. |
| /// |
| /// \param[in] debugger |
| /// The debugger instance where new Targets will be created as part of the |
| /// JSON data parsing. |
| /// |
| /// \param[in] trace_session_file |
| /// The contents of the trace session file describing the trace session. |
| /// See \a TraceSessionFileParser::BuildSchema for more information about |
| /// the schema of this JSON file. |
| /// |
| /// \param[in] session_file_dir |
| /// The path to the directory that contains the session file. It's used to |
| /// resolved relative paths in the session file. |
| static llvm::Expected<lldb::TraceSP> |
| FindPlugin(Debugger &debugger, const llvm::json::Value &trace_session_file, |
| llvm::StringRef session_file_dir); |
| |
| /// Get the schema of a Trace plug-in given its name. |
| /// |
| /// \param[in] plugin_name |
| /// Name of the trace plugin. |
| static llvm::Expected<llvm::StringRef> |
| FindPluginSchema(llvm::StringRef plugin_name); |
| |
| /// \return |
| /// The JSON schema of this Trace plug-in. |
| virtual llvm::StringRef GetSchema() = 0; |
| |
| /// Each decoded thread contains a cursor to the current position the user is |
| /// stopped at. When reverse debugging, each operation like reverse-next or |
| /// reverse-continue will move this cursor, which is then picked by any |
| /// subsequent dump or reverse operation. |
| /// |
| /// The initial position for this cursor is the last element of the thread, |
| /// which is the most recent chronologically. |
| /// |
| /// \return |
| /// The current position of the thread's trace or \b 0 if empty. |
| virtual size_t GetCursorPosition(const Thread &thread) = 0; |
| |
| /// Dump \a count instructions of the given thread's trace ending at the |
| /// given \a end_position position. |
| /// |
| /// The instructions are printed along with their indices or positions, which |
| /// are increasing chronologically. This means that the \a index 0 represents |
| /// the oldest instruction of the trace chronologically. |
| /// |
| /// \param[in] thread |
| /// The thread whose trace will be dumped. |
| /// |
| /// \param[in] s |
| /// The stream object where the instructions are printed. |
| /// |
| /// \param[in] count |
| /// The number of instructions to print. |
| /// |
| /// \param[in] end_position |
| /// The position of the last instruction to print. |
| /// |
| /// \param[in] raw |
| /// Dump only instruction addresses without disassembly nor symbol |
| /// information. |
| void DumpTraceInstructions(Thread &thread, Stream &s, size_t count, |
| size_t end_position, bool raw); |
| |
| /// Run the provided callback on the instructions of the trace of the given |
| /// thread. |
| /// |
| /// The instructions will be traversed starting at the given \a position |
| /// sequentially until the callback returns \b false, in which case no more |
| /// instructions are inspected. |
| /// |
| /// The purpose of this method is to allow inspecting traced instructions |
| /// without exposing the internal representation of how they are stored on |
| /// memory. |
| /// |
| /// \param[in] thread |
| /// The thread whose trace will be traversed. |
| /// |
| /// \param[in] position |
| /// The instruction position to start iterating on. |
| /// |
| /// \param[in] direction |
| /// If \b TraceDirection::Forwards, then then instructions will be |
| /// traversed forwards chronologically, i.e. with incrementing indices. If |
| /// \b TraceDirection::Backwards, the traversal is done backwards |
| /// chronologically, i.e. with decrementing indices. |
| /// |
| /// \param[in] callback |
| /// The callback to execute on each instruction. If it returns \b false, |
| /// the iteration stops. |
| virtual void TraverseInstructions( |
| const Thread &thread, size_t position, TraceDirection direction, |
| std::function<bool(size_t index, llvm::Expected<lldb::addr_t> load_addr)> |
| callback) = 0; |
| |
| /// Stop tracing a live thread |
| /// |
| /// \param[in] thread |
| /// The thread object to stop tracing. |
| /// |
| /// \return |
| /// An \a llvm::Error if stopping tracing failed, or \b |
| /// llvm::Error::success() otherwise. |
| virtual llvm::Error StopTracingThread(const Thread &thread) { |
| return llvm::make_error<UnimplementedError>(); |
| } |
| |
| /// Get the number of available instructions in the trace of the given thread. |
| /// |
| /// \param[in] thread |
| /// The thread whose trace will be inspected. |
| /// |
| /// \return |
| /// The total number of instructions in the trace. |
| virtual size_t GetInstructionCount(const Thread &thread) = 0; |
| }; |
| |
| } // namespace lldb_private |
| |
| #endif // LLDB_TARGET_TRACE_H |