If the PC was explicitly specified, the SAL is not changed.
If the line number was explicitly specified, at most the SAL's PC
is updated. If SAL is already past the prologue, then do nothing. */
If the PC was explicitly specified, the SAL is not changed.
If the line number was explicitly specified, at most the SAL's PC
is updated. If SAL is already past the prologue, then do nothing. */