@Override
				public FileParseResult call() {
					// this incurred a great deal of overhead and was causing significant variations in performance results.
					//System.out.format("Parsing file %s\n", input.getSourceName());
					try {
						return factory.parseFile(input, currentPass, ((NumberedThread)Thread.currentThread()).getThreadNumber());
					} catch (IllegalStateException ex) {
						ex.printStackTrace(System.err);
					} catch (Throwable t) {
						t.printStackTrace(System.err);
					}

					return null;
				}
This method is separate from {@link #parse1} so the first pass can be distinguished when analyzing
 profiler results.
tool-testsuite/test/org/antlr/v4/test/tool/TestPerformance.java