private String checkLabels() {
		List<String> errors = new ArrayList<>();
		for (SleighSymbol sym : symbolMap.values()) {
			if (sym.getType() != symbol_type.label_symbol) {
				continue;
			}
			LabelSymbol labsym = (LabelSymbol) sym;
			if (labsym.getRefCount() == 0) {
				errors.add(MessageFormattingUtils.format(labsym.location,
					String.format("Label <%s> was placed but never used", sym.getName())));

			}
			else if (!labsym.isPlaced()) {
				errors.add(MessageFormattingUtils.format(labsym.location,
					String.format("Label <%s> was referenced but never placed", sym.getName())));
			}
		}
		return errors.stream().collect(Collectors.joining("  "));

	}
Inject a symbol representing an "operand" to the pcode snippet.

<p>
This puts a placeholder in the resulting template, which gets filled in with the context
specific storage locations when final p-code is generated

@param loc is location information for the operand
@param name of operand symbol
@param index to use for the placeholder
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/lang/PcodeParser.java