Time-Travel Debugger with Historical State Visualization

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Solution Overview

Problem

Debugging software applications is time-consuming due to the challenges of reproducing and localizing runtime errors, as existing debugging tools lack the ability to effectively visualize and interact with historical states of code elements across prior executions.

Innovation Solution

The development of a debugger that leverages bit-accurate time travel traces to provide rich debugging experiences by visualizing historical states of code elements, including memory values and function return values, and simulates the execution of functions at specific time points to present accurate data values and their timing knowledge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If conventional debugging tools are used to trace and visualize execution, then execution tracking capability is improved, but the ability to interact with historical states of code elements is insufficient

Engineering Contradiction:
Improveexecution tracking capabilityVSAvoidinteraction with historical states
Core Design Contradiction:
Difficulty of detecting and measuringVSEase of operation

Solution Approach 1:

The system performs preliminary actions by recording execution traces and capturing historical states before the actual debugging interaction. The trace recorder captures memory values, register states, and execution context at various points in time, preparing this data in advance so that when a developer requests historical state information, it is already available for immediate visualization and interaction without requiring complex real-time computation during the debugging session.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If time travel debugging is implemented to replay execution, then historical state visualization is improved, but the complexity of the debugging system increases

Engineering Contradiction:
Improvehistorical state visualizationVSAvoiddebugging system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system segments the complex time travel debugging functionality into distinct modular components: a trace recorder that captures execution data, a state manager that stores and organizes historical states, and a visualization component that presents the information to the developer. Each module handles specific tasks independently, making the overall complex system more manageable and easier to implement while maintaining the capability to visualize historical states across multiple execution points.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of modifying the original execution process, the system creates copies of execution states by recording traces during normal operation. The trace recorder captures snapshots of memory, registers, and execution context, creating duplicate representations of historical states that can be visualized and interacted with without affecting the actual program execution. This copying approach simplifies the system by allowing historical state manipulation independent of the original execution flow.

Inventive Principle:
Principle #26Copying

3Measurement precision

If comprehensive trace data is collected to reconstruct execution states, then the accuracy of historical state representation is improved, but the amount of data processing required increases

Engineering Contradiction:
Improvehistorical state representation accuracyVSAvoiddata processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system extracts only the essential information needed for accurate historical state representation from the comprehensive execution trace. Rather than processing all raw trace data, the state manager selectively extracts memory values, register states, and execution context that are relevant to the current debugging task. This extraction process filters out unnecessary data while maintaining the accuracy of historical state representation, significantly reducing the data processing time required during both recording and visualization phases.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3785124B1Memory validity states in time-travel debugging
Publication Date: 2024.01.17 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3785124B1 patent drawingFigure 1
  • EP3785124B1 patent drawingFigure 2~3
  • EP3785124B1 patent drawingFigure 4A

AI summary

Presenting historical state associated with prior execution of an entity. Based on replaying segment(s) of execution of an entity based on a trace, embodiments could present an indication of whether a value of a code element is, at a first execution time point, unknown, known, previously known, and/or known in the future. Additionally, or alternatively, embodiments could present an indication of a value relied upon by simulated execution of a function at a second execution time point, along with an indication of a timing of knowledge of the value in relation to the second execution time point. Additionally, or alternatively, embodiments could present an indication that a return value of a function would be known if the function had executed at a third execution time point, or an indication that the return value would be unknown if the function had executed at the third execution time point.