Abstract

Informally, a call graph represents calls between entities in a given program. The call graphs that compilers compute to determine the applicability of an optimization must typically be conservative: a call may be omitted only if it can never occur in any execution of the program. Numerous software engineering tools also extract call graphs with the expectation that they will help software engineers increase their understanding of a program. The requirements placed on software engineering tools when computing call graphs are typically more relaxed than for compilers. For example, some false negatives---calls that can in fact take place in some execution of the program, but which are omitted from the call graph---may be acceptable, depending on the understanding task at hand. In this paper we empirically show a consequence of this spectrum of requirements by comparing the C call graphs extracted from three software systems (mapmaker, mosaic, and gcc) by five extraction tools (cflow, CIA...

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