1. A computer-implemented method for analyzing test coverage of a program under test, comprising: executing the program under test using a test case; generating a heapdump file containing call stack information of called subroutines of the program under test; obtaining based upon an analysis of the call stack information, coverage information; wherein the analyzing includes: performing a hash operation on each function call entry, and an obtained hash code is an identification of the function call entry, and recording an association between the identification and a corresponding function call stack and test case, wherein a call stack consists of stack frames each of which corresponds to one of the called subroutines.