Include memory usage in -diagnostics report

Author: ahejlsberg

src/compiler/sys.ts

@@ -234,7 +234,9 @@ var sys: System = (function () {
                 return (<any>process).cwd();
             },
             getMemoryUsage() {
-                global.gc();
+                if (global.gc) {
+                    global.gc();
+                }
                 return process.memoryUsage().heapUsed;
             },
             exit(exitCode?: number): void {

src/compiler/tsc.ts

@@ -337,12 +337,16 @@ module ts {
 
         reportDiagnostics(errors);
         if (commandLine.options.diagnostics) {
+            var memoryUsed = sys.getMemoryUsage();
             reportCountStatistic("Files", program.getSourceFiles().length);
             reportCountStatistic("Lines", countLines(program));
             reportCountStatistic("Nodes", checker ? checker.getNodeCount() : 0);
             reportCountStatistic("Identifiers", checker ? checker.getIdentifierCount() : 0);
             reportCountStatistic("Symbols", checker ? checker.getSymbolCount() : 0);
             reportCountStatistic("Types", checker ? checker.getTypeCount() : 0);
+            if (memoryUsed) {
+                reportStatisticalValue("Memory used", Math.round(memoryUsed / 1000) + "K");
+            }
             reportTimeStatistic("Parse time", bindStart - parseStart);
             reportTimeStatistic("Bind time", checkStart - bindStart);
             reportTimeStatistic("Check time", emitStart - checkStart);