Method SelectLoopCtrlVar

src/VariableSelector.cpp:1133–1166

-------------------------------------------------------------- select a loop control variable, which is restricted to integers * only * * JYTODO: make pointers control variables? ************************************************************/

  * JYTODO: make pointers control variables?
  ************************************************************/
Variable *
VariableSelector::SelectLoopCtrlVar(const CGContext &cg_context, const vector<const Variable*>& invalid_vars)
{
	// Note that many of the functions that select `var' can return null, if
	const Type* type = get_int_type();
	vector<Variable*> vars;
	find_all_non_array_visible_vars(cg_context.get_current_block(), vars);
	// remove union variables that have both integer field(s) and pointer field(s)
	// because incrementing the integer field causes the pointer to be invalid, and the current
	// points-to analysis simply assumes loop stepping has no pointer effect
	size_t len = vars.size();
	for (size_t i=0; i<len; i++) {
		if (vars[i]->type &&
			(!vars[i]->type->has_int_field() ||		// remove variables isn't (or doesn't contain) integers
			(vars[i]->type->eType == eUnion &&
			vars[i]->type->contain_pointer_field()))) {
			vars.erase(vars.begin() + i);
			i--;
			len--;
		}
	}
	Variable* var = choose_var(vars, Effect::WRITE, cg_context, type, 0, eConvert, invalid_vars, true);
	ERROR_GUARD(NULL);
	if (var == NULL) {
		if (CGOptions::global_variables()) {
			var = GenerateNewGlobal(Effect::WRITE, cg_context, type, 0);
		}
		else {
			var = GenerateNewParentLocal(*cg_context.get_current_block(),
					Effect::WRITE, cg_context, type, 0);
		}
	}
	return var;
}

// --------------------------------------------------------------
// Select or Create a new variable visible to this scope (new var may be