A debugging method is described wherein a debug information file is constructed which includes information that identifies changes of variable value assignments to registers at plural steps of program. The information further includes data that identifies any change of sequence of machine code instructions from the sequence of source code instructions that gave rise to the machine code instructions. Using such information, hidden breakpoints are inserted into the machine code (wherein a hidden breakpoint enables access to an instruction to either store a variable value from an identified register or to move to a machine code instruction that corresponds in order to a source code instruction that gave rise to the machine code instruction). Thereafter, the program is executed under control of a debug program and, upon encountering a hidden breakpoint, automatically either stores the variable value that exists in the identified register or moves to execute a machine code instruction that is indicated by the hidden breakpoint. The actions carried out in response to encountering the hidden breakpoint are invisible to the user.