Abstract: The invention enables a compiler (during its first compilation pass) to insert identifiers during an early optimization phase into machine-independent code. The identifiers are used for identifying specific instructions of the machine-independent code. The compiler may use a table to record the assignment of identifiers and their corresponding portion of machine-independent code. During subsequent optimization phases of the first compilation pass, portions of machine-independent code are transformed into portions of machine-dependent code, and the machine-dependent code inherits identification associated with the portions of machine-independent code that were used to generate the portions of machine-dependent code. After the first compilation pass, executable code is made to interact with test data to generate statistical execution data which is collected by previously inserted counters. The collected counter data is consolidated so that it relates to the instructions of the machine-independent code.