To declare global variables, using a mixture of I6 Globals and array entries.

§1.

void I6TargetVariables::create_generator?Usage of I6TargetVariables::create_generator:
Generating Inform 6 - §1(code_generator *gtr) {
    METHOD_ADD(gtr, DECLARE_VARIABLES_MTID, I6TargetVariables::declare_variables);
    METHOD_ADD(gtr, EVALUATE_VARIABLE_MTID, I6TargetVariables::evaluate_variable);
}

§2. In an ideal world we would implement all Inter global variables using Global, thus making them I6 global variables as well. But when I6 compiles to the Z-machine VM, there's an absolute limit of 240 globals, so we do not live in an ideal world. As a compromise, we make all the kit-declared variables use Global (for speed) and have all of the rest use entries in an array called Global_Vars, at the cost of a lookup whenever we read or write them.

void I6TargetVariables::declare_variables?Usage of I6TargetVariables::declare_variables:
§1(code_generator *gtr, code_generation *gen,
    linked_list *L) {
    int k = 1;
    inter_symbol *var_name;
    LOOP_OVER_LINKED_LIST(var_name, inter_symbol, L) {
        inter_tree_node *P = var_name->definition;
        inter_pair val = VariableInstruction::value(P);
        if (SymbolAnnotation::get_b(var_name, ASSIMILATED_IANN) == FALSE) {
            if (k == 1) Begin the array2.1;
            Variables created by Inform 7 source text all go into the array2.2;
        } else {
            Variables created by kits all become Globals in I62.4;
        }
    }
    if (k > 1) End the array2.3;
}

§2.1. Begin the array2.1 =

    segmentation_pos saved = CodeGen::select(gen, global_variables_array_I7CGS);
    text_stream *OUT = CodeGen::current(gen);
    WRITE("Array Global_Vars --> 0\n");
    CodeGen::deselect(gen, saved);

• This code is used in §2.

§2.2. Variables created by Inform 7 source text all go into the array2.2 =

    SymbolAnnotation::set_i(var_name, I6_GLOBAL_OFFSET_IANN, (inter_ti) k);
    segmentation_pos saved = CodeGen::select(gen, global_variables_array_I7CGS);
    text_stream *OUT = CodeGen::current(gen);
    WRITE("  (");
    CodeGen::pair(gen, P, val);
    WRITE(") ! -->%d = %S (%S)\n", k,
        InterSymbol::trans(var_name), InterSymbol::identifier(var_name));
    CodeGen::deselect(gen, saved);
    k++;

• This code is used in §2.

§2.3. End the array2.3 =

    segmentation_pos saved = CodeGen::select(gen, global_variables_array_I7CGS);
    text_stream *OUT = CodeGen::current(gen);
    WRITE(";\n");
    CodeGen::deselect(gen, saved);

• This code is used in §2.

§2.4. Variables created by kits all become Globals in I62.4 =

    segmentation_pos saved = CodeGen::select(gen, global_variables_I7CGS);
    text_stream *OUT = CodeGen::current(gen);
    WRITE("Global %S = ", InterSymbol::trans(var_name));
    CodeGen::pair(gen, P, val);
    WRITE(";\n");
    CodeGen::deselect(gen, saved);

• This code is used in §2.

§3. And the following is called when we want to compile an lvalue or rvalue for the variable (lvalue in the case of as_reference being set).

void I6TargetVariables::evaluate_variable?Usage of I6TargetVariables::evaluate_variable:
§1(code_generator *gtr, code_generation *gen,
    inter_symbol *var_name, int as_reference) {
    text_stream *OUT = CodeGen::current(gen);
    int k = SymbolAnnotation::get_i(var_name, I6_GLOBAL_OFFSET_IANN);
    if (k > 0) WRITE("(Global_Vars-->%d)", k);
    else WRITE("%S", InterSymbol::trans(var_name));
}