Generate deterministic named identifier based on a source location,
such that the name is consistent across multiple compilations.
A new unique name is generated. If the prefix+location is already in
the stringtable, an extra suffix is added (starting the count at "_1").
Generate deterministic named identifier based on a source location, such that the name is consistent across multiple compilations. A new unique name is generated. If the prefix+location is already in the stringtable, an extra suffix is added (starting the count at "_1").