Code Analyzer Redundant Instance Variable Initialization Elision

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Solution Overview

Problem

Traditional source code analyzers often incorrectly identify instance variable assignments of default values as redundant, leading to incorrect warnings and potential program errors, as they lack advanced analysis capabilities to distinguish between necessary and unnecessary initializations.

Innovation Solution

A code analyzer is enhanced to determine whether instance variable assignments are definitely redundant, definitely not redundant, or possibly redundant, using algorithms that analyze the source code to identify redundant initializations and elide them from compiled code or provide informative warnings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional source code analyzers identify all instance variable assignments of default values as redundant, then the number of warnings issued increases, but the accuracy of warnings decreases leading to incorrect identifications

Engineering Contradiction:

Improveaccuracy of redundancy detectionVSAvoidcomplexity of analysis algorithm

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The analysis is divided into multiple stages: first identifying candidate redundant assignments, then analyzing control flow to determine if the variable is actually used, and finally distinguishing between definitely redundant, possibly redundant, and not redundant cases. This segmented approach improves accuracy while managing algorithmic complexity through progressive refinement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary analysis to establish control flow information and variable usage patterns before making redundancy determinations. By pre-comparing assignment locations with usage locations and establishing definite assignment states, the system prepares necessary information in advance to accurately identify redundant assignments without requiring overly complex real-time analysis.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If redundant initializations are removed from source code, then code size and execution time decrease, but program correctness may be compromised if necessary initializations are incorrectly removed

Engineering Contradiction:

Improvecode compilation efficiencyVSAvoidprogram correctness

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system provides feedback through multiple classification levels (definitely redundant, possibly redundant, not redundant) and allows developers to review and adjust the analysis results. This feedback mechanism ensures that program correctness is maintained by allowing verification before automatic removal, preventing incorrect eliminations of necessary initializations.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces manual code review with an automated code analyzer that uses algorithms to detect redundant assignments. This substitution improves productivity by automatically analyzing code without requiring manual inspection, while maintaining reliability through sophisticated analysis that distinguishes between different types of redundancy with high accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If basic analysis is used to identify redundant assignments, then the analysis process is simple and fast, but incorrect warnings are issued when assignments are not actually redundant

Engineering Contradiction:

Improvesimplicity of analysis processVSAvoidaccuracy of redundancy detection

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The analysis process dynamically adjusts its depth based on the situation. For clearly redundant cases, simple analysis suffices. For ambiguous cases where control flow or variable usage is uncertain, the system performs more detailed analysis to determine if the assignment is definitely redundant, possibly redundant, or not redundant. This dynamic approach maintains simplicity where possible while improving accuracy when needed.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10127133B2Redundant instance variable initialization elision

Publication Date: 2018.11.13 ORACLE INT CORP

AI summary

A compiler, IDE or other code analyzer may determine whether an instance variable declaration assignment is redundant. The code analyzer may also take action based on that determination. A code analyzer may be able to determine with certainty that a particular instance variable initialization or assignment is definitely redundant. The code analyzer may cause a compiler to automatically elide the redundant assignment from compiled source code. The code analyzer may be able to determine with certainty that a particular assignment is definitely not redundant. Additionally, a code analyzer may not be able to determine with certainty whether an instance variable assignment is definitely redundant or definitely not redundant. Additionally, the code analyzer may report a warning or other informative message indicating the redundancy property of the assignment, thus alerting the programming to a (possibly) redundant assignment.