void commit()
{
debug ("COMMIT: {0:x} {1} {2} {3}", stm.st_address, stm.st_line,
stm.st_file, stm.start_file);
lines.Add (new LineNumber (stm.st_file, stm.st_line, stm.st_address));
stm.basic_block = false;
stm.prologue_end = false;
stm.epilogue_begin = false;
}