To make sure certain symbol names translate into globally unique target symbols.

§1. Pipeline stage. 

void CodeGen::Uniqueness::create_pipeline_stage(void) {
    CodeGen::Stage::new(I"make-identifiers-unique", CodeGen::Uniqueness::run_pipeline_stage, NO_STAGE_ARG, FALSE);
}

int CodeGen::Uniqueness::run_pipeline_stage(pipeline_step *step) {
    dictionary *D = Dictionaries::new(INITIAL_INTER_SYMBOLS_ID_RANGE, FALSE);
    InterTree::traverse(step->repository, CodeGen::Uniqueness::visitor, D, NULL, 0);
    return TRUE;
}

typedef struct uniqueness_count {
    int count;
    CLASS_DEFINITION
} uniqueness_count;

void CodeGen::Uniqueness::visitor(inter_tree *I, inter_tree_node *P, void *state) {
    dictionary *D = (dictionary *) state;
    if (P->W.data[ID_IFLD] == PACKAGE_IST) {
        inter_package *Q = Inter::Package::defined_by_frame(P);
        inter_symbols_table *ST = Inter::Packages::scope(Q);
        for (int i=0; i<ST->size; i++) {
            inter_symbol *S = ST->symbol_array[i];
            if ((S) && (S->equated_to == NULL) && (Inter::Symbols::get_flag(S, MAKE_NAME_UNIQUE))) {
                text_stream *N = S->symbol_name;
                uniqueness_count *U = NULL;
                if (Dictionaries::find(D, N)) {
                    U = (uniqueness_count *) Dictionaries::read_value(D, N);
                } else {
                    U = CREATE(uniqueness_count);
                    U->count = 0;
                    Dictionaries::create(D, N);
                    Dictionaries::write_value(D, N, (void *) U);
                }
                U->count++;
                TEMPORARY_TEXT(T)
                WRITE_TO(T, "%S_U%d", N, U->count);
                Inter::Symbols::set_translate(S, T);
                DISCARD_TEXT(T)
                Inter::Symbols::clear_flag(S, MAKE_NAME_UNIQUE);
            }
        }
    }
}