Examining The Prevalence and The Historical Trends of Indirect Function Calls in Open Source Systems: A Case Study, gcc 2001-2011

摘要

An empirical study that examines the prevalence and distribution of indirect function calls using function pointers and virtual methods in general-purpose software systems is presented. The study is conducted on a well-known, large-scale software system, gcc.4.5.3, comprising over four million lines of code. The system is analyzed and the number of function pointer and virtual method calls is determined. Additionally, function pointers are categorized based on their type and the complexity they pose when conducting inter-procedural static analysis. The results show that more often than not, function pointers are used in situations that make analysis very difficult (i.e., NP-hard). Thus, conducting accurate program analysis (e.g., program slicing, call graph generation) becomes very costly, or impractical, to conduct. Analysis of the historical data over a ten-year period of gcc shows that there is an increase in the usage of both calls using function pointers and virtual methods over its lifetime, thus posing further problems for inter-procedural analysis.