Which target functions in a target binary have target function basic blocks that match the source function basic blocks in a source function in a source binary is determined. For the target functions having matching target function basic blocks, a target function control flow graph is determined that has the greatest control flow matching strength to a source function control flow graph, wherein a node in the source function control graph represents a source function basic block, wherein a node in a target function control graph represents a target function basic block in a corresponding target function.