IL Optimization: Detecting and Eliminating Redundant Eflags by Flag Relevant Chain
Xue Lei, Wenqing Fan, Wei Huang, Yixian Yang, Zhongxian Li · The Open Automation and Control Systems Journal · 2015
In this paper, we proposed a systematic approach for automatically detecting and elimination redundant Eflags to optimize intermediate language (IL).We analyzed a broad spectrum of different IL and found that a number of IL expose all side effects explicitly by default and that not all the Eflags are relevant with subsequent analysis.Therefore, we proposed a unified approach, invertible analysis, to reduce the volume of IL.Our approach does not rely on any concrete IL, and thus can identify redundant Eflags in the IL.Moreover, we devised a method using flag relevant chain dependency analysis to remove redundant Eflags and shrink the IL.We developed a prototype, and conducted extensive experiments using representative samples from various categories.We demonstrated that our approach could diminish the volume of Vine IL obviously, and provide accurate representation about the assembly code.