Symbolic Execution Simplifies Memory Access Operations
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Solution Overview
Problem
Existing program analysis techniques face challenges in efficiently handling memory-access operations, particularly due to the complexity of aliasing and the limitations of current simplification methods which either lead to poor performance or loss of precision.
Innovation Solution
The method simplifies the symbolic representation of a program on-the-fly by analyzing and simplifying memory-access operations during the translation process, allowing for efficient handling of complex memory accesses beyond constant value cases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If memory-access operations are handled precisely considering all possible aliasing, then measurement precision is improved, but productivity deteriorates
Solution Approach 1:
The system performs preliminary actions by translating and simplifying the program to a symbolic representation before the actual analysis takes place. The front-end module converts the input program into a simplified symbolic form that captures essential memory access patterns, enabling the core analyzer to work with pre-processed, simplified data rather than raw program code, thus improving both precision and performance
Solution Approach 2:
The patent introduces a symbolic representation as an intermediary between the raw program and the analysis process. This symbolic form acts as a mediator that abstracts away complex memory aliasing details while preserving essential access patterns, allowing the analyzer to achieve precise results without being overwhelmed by the full complexity of memory operations
2Productivity
If memory is abstracted away to improve performance, then productivity is improved, but measurement precision deteriorates
Solution Approach 1:
The symbolic representation applies different levels of abstraction to different parts of the program. Memory access operations that are critical for precision are represented in detail, while other parts are abstracted away. This local differentiation allows the system to maintain precision where needed while achieving performance improvements through abstraction elsewhere
Solution Approach 2:
The system changes the parameters of memory representation by translating concrete memory addresses and access patterns into symbolic forms. This parameter transformation allows the analyzer to work with simplified symbolic addresses rather than concrete memory locations, improving performance while preserving the essential relationships needed for precise analysis
3Productivity
If standard simplification rules from array theory are applied, then productivity is improved, but measurement precision deteriorates due to limitations with non-constant addresses
Solution Approach 1:
The simplification system is designed to be dynamic and adaptive rather than static. It can adjust the level and type of simplification applied based on the specific characteristics of the program being analyzed. The symbolic representation allows the system to handle both constant and non-constant addresses with appropriate simplification strategies, making the simplification process flexible and context-aware
Solution Approach 2:
The patent segments the simplification process into different stages and components. The front-end module performs initial translation and simplification, while the core analyzer performs additional simplification during analysis. This segmentation allows complex memory access patterns to be handled systematically through multiple passes of simplification rather than requiring all simplifications to be applied at once
Data Source
AI summary
A computer implemented method is provided for performing symbolic execution on a symbolic representation of a computer program comprising a sequence of software instructions represented at least by variables, memories and expressions. The method is operated on-the-fly and comprises for each software instruction of the computer program: analyzing an initial symbolic representation of a software instruction to determine if a simplification may be applied to any memory-access operation included in the initial symbolic representation of the software instruction; in case of determining a simplification, generating a simplified symbolic representation of the software instruction to replace the initial symbolic representation; and generating a new symbolic representation of the computer program with the simplified symbolic representation of the software instruction.