Fire 'stack' getter of error objects after GC.

test/mjsunit/stack-traces-gc.js

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 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Flags: --expose-gc
+// Flags: --expose-gc --allow-natives-syntax
 
-// Handy abbreviation.
-var dp = Object.defineProperty;
+var fired = [];
+for (var i = 0; i < 100; i++) fired[i] = false;
 
-function getter() { return 111; }
-function setter(x) { print(222); }
-function anotherGetter() { return 333; }
-function anotherSetter(x) { print(444); }
-var obj1, obj2;
+function getter_function(i) {
+  return %MarkOneShotGetter( function() { fired[i] = true; } );
+}
 
-// obj1 and obj2 share the getter accessor.
-obj1 = {};
-dp(obj1, "alpha", { get: getter, set: setter });
-obj2 = {}
-dp(obj2, "alpha", { get: getter });
-obj1 = {};
-assertEquals(111, obj2.alpha);
+// Error objects that die young.
+for (var i = 0; i < 100; i++) {
+  var error = new Error();
+  // Replace the getter to observe whether it has been fired,
+  // and disguise it as original getter.
+  var getter = getter_function(i);
+  error.__defineGetter__("stack", getter);
+
+  error = undefined;
+}
+
 gc();
-assertEquals(111, obj2.alpha);
+for (var i = 0; i < 100; i++) {
+  assertFalse(fired[i]);
+}
 
-// obj1, obj2, and obj3 share the getter accessor.
-obj1 = {};
-dp(obj1, "alpha", { get: getter, set: setter });
-obj2 = {}
-dp(obj2, "alpha", { get: getter });
-obj1 = {};
+// Error objects that are kept alive.
+var array = [];
+for (var i = 0; i < 100; i++) {
+  var error = new Error();
+  var getter = getter_function(i);
+  // Replace the getter to observe whether it has been fired,
+  // and disguise it as original getter.
+  error.__defineGetter__("stack", getter);
+
+  array.push(error);
+  error = undefined;
+}
+
 gc();
-obj3 = {}
-dp(obj3, "alpha", { get: getter });
+// We don't expect all stack traces to be formatted after only one GC.
+assertTrue(fired[0]);
 
+for (var i = 0; i < 10; i++) gc();
+for (var i = 0; i < 100; i++) assertTrue(fired[i]);
 
-// obj1 and obj2 share the getter and setter accessor.
-obj1 = {};
-dp(obj1, "alpha", { get: getter, set: setter });
-obj1.beta = 10;
-obj2 = {}
-dp(obj2, "alpha", { get: getter, set: setter });
-obj1 = {};
-assertEquals(111, obj2.alpha);
+// Error objects with custom stack getter.
+var custom_error = new Error();
+var custom_getter_fired = false;
+custom_error.__defineGetter__("stack",
+                              function() { custom_getter_fired = true; });
 gc();
-obj2.alpha = 100
-assertEquals(111, obj2.alpha);
+assertFalse(custom_getter_fired);