A technique for building a callgraph for a software program that includes multiple function entry points using dynamic instrumentation. In one example embodiment, this is achieved by inserting function count probe code at each function entry point of each multiple entry function having multiple function entry points in the software program. Inter-entry point arc probe code is then inserted substantially before each arc source address of an arc. A performance analysis tool is then used to collect data resulting from execution of the software program including the function count probe code and the inter-entry point arc probe code and to obtain an actual function count value for each multiple entry function. A callgraph is then built using the obtained actual function count values.