reduce memory pressure via bit fields (#5203)

2021-12-06 03:30:05 +00:00
parent b0799105c2
commit 033d8d9405
8 changed files with 97 additions and 21 deletions
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -273,3 +273,21 @@ function first_in_statement(stack, arrow, export_default) {
        return false;
    }
 }
+
+function DEF_BITPROPS(ctor, props) {
+    if (props.length > 31) throw new Error("Too many properties: " + props.length + "\n" + props.join(", "));
+    props.forEach(function(name, pos) {
+        var mask = 1 << pos;
+        Object.defineProperty(ctor.prototype, name, {
+            get: function() {
+                return !!(this._bits & mask);
+            },
+            set: function(val) {
+                if (val)
+                    this._bits |= mask;
+                else
+                    this._bits &= ~mask;
+            },
+        });
+    });
+}