fs: include more fs.stat*() optimizations

Including:

* Move async *stat() functions to FillStatsArray() now used by the
sync *stat() functions

* Avoid creating fs.Stats instances for implicit async/sync *stat()
calls used in various fs functions

* Store reference to Float64Array data on C++ side for easier/faster
access, instead of passing from JS to C++ on every async/sync *stat()
call

Backport-PR-URL: nodejs#11665
Fixes: nodejs#16496

benchmark/fs/bench-stat.js

@@ -4,20 +4,30 @@ const common = require('../common');
 const fs = require('fs');
 
 const bench = common.createBenchmark(main, {
-  n: [1e4],
-  kind: ['lstat', 'stat']
+  n: [20e4],
+  kind: ['fstat', 'lstat', 'stat']
 });
 
 
 function main(conf) {
   const n = conf.n >>> 0;
+  const kind = conf.kind;
+  var arg;
+  if (kind === 'fstat')
+    arg = fs.openSync(__filename, 'r');
+  else
+    arg = __filename;
 
   bench.start();
   (function r(cntr, fn) {
-    if (cntr-- <= 0)
-      return bench.end(n);
-    fn(__filename, function() {
+    if (cntr-- <= 0) {
+      bench.end(n);
+      if (kind === 'fstat')
+        fs.closeSync(arg);
+      return;
+    }
+    fn(arg, function() {
       r(cntr, fn);
     });
-  }(n, fs[conf.kind]));
+  }(n, fs[kind]));
 }

benchmark/fs/bench-statSync.js

@@ -4,36 +4,23 @@ const common = require('../common');
 const fs = require('fs');
 
 const bench = common.createBenchmark(main, {
-  n: [1e4],
+  n: [1e6],
   kind: ['fstatSync', 'lstatSync', 'statSync']
 });
 
 
 function main(conf) {
   const n = conf.n >>> 0;
-  var fn;
-  var i;
-  switch (conf.kind) {
-    case 'statSync':
-    case 'lstatSync':
-      fn = fs[conf.kind];
-      bench.start();
-      for (i = 0; i < n; i++) {
-        fn(__filename);
-      }
-      bench.end(n);
-      break;
-    case 'fstatSync':
-      fn = fs.fstatSync;
-      const fd = fs.openSync(__filename, 'r');
-      bench.start();
-      for (i = 0; i < n; i++) {
-        fn(fd);
-      }
-      bench.end(n);
-      fs.closeSync(fd);
-      break;
-    default:
-      throw new Error('Invalid kind argument');
+  const kind = conf.kind;
+  const arg = (kind === 'fstatSync' ? fs.openSync(__filename, 'r') : __dirname);
+  const fn = fs[conf.kind];
+
+  bench.start();
+  for (var i = 0; i < n; i++) {
+    fn(arg);
   }
+  bench.end(n);
+
+  if (kind === 'fstat')
+    fs.closeSync(arg);
 }

benchmark/fs/readFileSync.js

@@ -0,0 +1,17 @@
+'use strict';
+
+var common = require('../common.js');
+var fs = require('fs');
+
+var bench = common.createBenchmark(main, {
+  n: [60e4]
+});
+
+function main(conf) {
+  var n = +conf.n;
+
+  bench.start();
+  for (var i = 0; i < n; ++i)
+    fs.readFileSync(__filename);
+  bench.end(n);
+}