1 files changed, 193 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/gc/weak-marking-01.js b/js/src/jit-test/tests/gc/weak-marking-01.js
new file mode 100644
index 000000000..7a100f6e1
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+++ b/js/src/jit-test/tests/gc/weak-marking-01.js
@@ -0,0 +1,193 @@
+// These tests will be using object literals as keys, and we want some of them
+// to be dead after being inserted into a WeakMap. That means we must wrap
+// everything in functions because it seems like the toplevel script hangs onto
+// its object literals.
+
+// All reachable keys should be found, and the rest should be swept.
+function basicSweeping() {
+  var wm1 = new WeakMap();
+  wm1.set({'name': 'obj1'}, {'name': 'val1'});
+  var hold = {'name': 'obj2'};
+  wm1.set(hold, {'name': 'val2'});
+  wm1.set({'name': 'obj3'}, {'name': 'val3'});
+
+  startgc(100000, 'shrinking');
+  gcslice();
+
+  assertEq(wm1.get(hold).name, 'val2');
+  assertEq(nondeterministicGetWeakMapKeys(wm1).length, 1);
+}
+
+basicSweeping();
+
+// Keep values alive even when they are only referenced by (live) WeakMap values.
+function weakGraph() {
+  var wm1 = new WeakMap();
+  var obj1 = {'name': 'obj1'};
+  var obj2 = {'name': 'obj2'};
+  var obj3 = {'name': 'obj3'};
+  var obj4 = {'name': 'obj4'};
+  var clear = {'name': ''}; // Make the interpreter forget about the last obj created
+
+  wm1.set(obj2, obj3);
+  wm1.set(obj3, obj1);
+  wm1.set(obj4, obj1); // This edge will be cleared
+  obj1 = obj3 = obj4 = undefined;
+
+  startgc(100000, 'shrinking');
+  gcslice();
+
+  assertEq(obj2.name, "obj2");
+  assertEq(wm1.get(obj2).name, "obj3");
+  assertEq(wm1.get(wm1.get(obj2)).name, "obj1");
+  print(nondeterministicGetWeakMapKeys(wm1).map(o => o.name).join(","));
+  assertEq(nondeterministicGetWeakMapKeys(wm1).length, 2);
+}
+
+weakGraph();
+
+// ...but the weakmap itself has to stay alive, too.
+function deadWeakMap() {
+  var wm1 = new WeakMap();
+  var obj1 = makeFinalizeObserver();
+  var obj2 = {'name': 'obj2'};
+  var obj3 = {'name': 'obj3'};
+  var obj4 = {'name': 'obj4'};
+  var clear = {'name': ''}; // Make the interpreter forget about the last obj created
+
+  wm1.set(obj2, obj3);
+  wm1.set(obj3, obj1);
+  wm1.set(obj4, obj1); // This edge will be cleared
+  var initialCount = finalizeCount();
+  obj1 = obj3 = obj4 = undefined;
+  wm1 = undefined;
+
+  startgc(100000, 'shrinking');
+  gcslice();
+
+  assertEq(obj2.name, "obj2");
+  assertEq(finalizeCount(), initialCount + 1);
+}
+
+deadWeakMap();
+
+// WeakMaps do not strongly reference their keys or values. (WeakMaps hold a
+// collection of (strong) references to *edges* from keys to values. If the
+// WeakMap is not live, then its edges are of course not live either. An edge
+// holds neither its key nor its value live; it just holds a strong ref from
+// the key to the value. So if the key is live, the value is live too, but the
+// edge itself has no references to anything.)
+function deadKeys() {
+  var wm1 = new WeakMap();
+  var obj1 = makeFinalizeObserver();
+  var obj2 = {'name': 'obj2'};
+  var obj3 = makeFinalizeObserver();
+  var clear = {}; // Make the interpreter forget about the last obj created
+
+  wm1.set(obj1, obj1);
+  wm1.set(obj3, obj2);
+  obj1 = obj3 = undefined;
+  var initialCount = finalizeCount();
+
+  startgc(100000, 'shrinking');
+  gcslice();
+
+  assertEq(finalizeCount(), initialCount + 2);
+  assertEq(nondeterministicGetWeakMapKeys(wm1).length, 0);
+}
+
+deadKeys();
+
+// The weakKeys table has to grow if it encounters enough new unmarked weakmap
+// keys. Trigger this to happen during weakmap marking.
+//
+// There's some trickiness involved in getting it to test the right thing,
+// because if a key is marked before the weakmap, then it won't get entered
+// into the weakKeys table. This chains through multiple weakmap layers to
+// ensure that the objects can't get marked before the weakmaps.
+function weakKeysRealloc() {
+  var wm1 = new WeakMap;
+  var wm2 = new WeakMap;
+  var wm3 = new WeakMap;
+  var obj1 = {'name': 'obj1'};
+  var obj2 = {'name': 'obj2'};
+  wm1.set(obj1, wm2);
+  wm2.set(obj2, wm3);
+  for (var i = 0; i < 10000; i++) {
+    wm3.set(Object.create(null), wm2);
+  }
+  wm3.set(Object.create(null), makeFinalizeObserver());
+  wm2 = undefined;
+  wm3 = undefined;
+  obj2 = undefined;
+
+  var initialCount = finalizeCount();
+  startgc(100000, 'shrinking');
+  gcslice();
+  assertEq(finalizeCount(), initialCount + 1);
+}
+
+weakKeysRealloc();
+
+// The weakKeys table is populated during regular marking. When a key is later
+// deleted, both it and its delegate should be removed from weakKeys.
+// Otherwise, it will hold its value live if it gets marked, and our table
+// traversals will include non-keys, etc.
+function deletedKeys() {
+  var wm = new WeakMap;
+  var g = newGlobal();
+
+  for (var i = 0; i < 1000; i++)
+    wm.set(g.Object.create(null), i);
+
+  startgc(100, 'shrinking');
+  for (var key of nondeterministicGetWeakMapKeys(wm)) {
+    if (wm.get(key) % 2)
+      wm.delete(key);
+  }
+
+  gc();
+}
+
+deletedKeys();
+
+// Test adding keys during incremental GC.
+function incrementalAdds() {
+  var initialCount = finalizeCount();
+
+  var wm1 = new WeakMap;
+  var wm2 = new WeakMap;
+  var wm3 = new WeakMap;
+  var obj1 = {'name': 'obj1'};
+  var obj2 = {'name': 'obj2'};
+  wm1.set(obj1, wm2);
+  wm2.set(obj2, wm3);
+  for (var i = 0; i < 10000; i++) {
+    wm3.set(Object.create(null), wm2);
+  }
+  wm3.set(Object.create(null), makeFinalizeObserver());
+  obj2 = undefined;
+
+  var obj3 = [];
+  startgc(100, 'shrinking');
+  var M = 10;
+  var N = 800;
+  for (var j = 0; j < M; j++) {
+    for (var i = 0; i < N; i++)
+      wm3.set(Object.create(null), makeFinalizeObserver()); // Should be swept
+    for (var i = 0; i < N; i++) {
+      obj3.push({'name': 'obj3'});
+      wm1.set(obj3[obj3.length - 1], makeFinalizeObserver()); // Should not be swept
+    }
+    gcslice();
+  }
+
+  wm2 = undefined;
+  wm3 = undefined;
+
+  gc();
+  print("initialCount = " + initialCount);
+  assertEq(finalizeCount(), initialCount + 1 + M * N);
+}
+
+incrementalAdds();