1 files changed, 584 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/gc/weak-marking-03.js b/js/src/jit-test/tests/gc/weak-marking-03.js
new file mode 100644
index 0000000000..9bb6acd15a
--- /dev/null
+++ b/js/src/jit-test/tests/gc/weak-marking-03.js
@@ -0,0 +1,584 @@
+// |jit-test| allow-unhandlable-oom
+
+// weakmap marking tests that use the testing mark queue to force an ordering
+// of marking.
+
+// We are carefully controlling the sequence of GC events.
+gczeal(0);
+
+// If a command-line parameter is given, use it as a substring restriction on
+// the tests to run.
+var testRestriction = scriptArgs[0];
+printErr(`testRestriction is ${testRestriction || '(run all tests)'}`);
+
+function runtest(func) {
+  if (testRestriction && ! func.name.includes(testRestriction)) {
+    print("\Skipping " + func.name);
+  } else {
+    print("\nRunning " + func.name);
+    func();
+  }
+}
+
+function reportMarks(prefix = "") {
+  const marks = getMarks();
+  const current = currentgc();
+  const markstr = marks.join("/");
+  print(`${prefix}[${current.incrementalState}/${current.sweepGroup}@${current.queuePos}] ${markstr}`);
+  return markstr;
+}
+
+function startGCMarking() {
+  startgc(100000);
+  while (gcstate() === "Prepare") {
+    gcslice(100000);
+  }
+}
+
+function purgeKey() {
+  const m = new WeakMap();
+  const vals = {};
+  vals.key = Object.create(null);
+  vals.val = Object.create(null);
+  m.set(vals.key, vals.val);
+
+  minorgc();
+
+  addMarkObservers([m, vals.key, vals.val]);
+
+  enqueueMark(m);
+  enqueueMark("yield");
+
+  enqueueMark(vals.key);
+  enqueueMark("yield");
+
+  vals.key = vals.val = null;
+
+  startGCMarking();
+  // getMarks() returns map/key/value
+  assertEq(getMarks().join("/"), "black/unmarked/unmarked",
+           "marked the map black");
+
+  gcslice(100000);
+  assertEq(getMarks().join("/"), "black/black/unmarked",
+           "key is now marked");
+
+  // Trigger purgeWeakKey: the key is in weakkeys (because it was unmarked when
+  // the map was marked), and now we're removing it.
+  m.delete(nondeterministicGetWeakMapKeys(m)[0]);
+
+  finishgc(); // Finish the GC
+  assertEq(getMarks().join("/"), "black/black/black",
+           "at end, value is marked too");
+
+  clearMarkQueue();
+  clearMarkObservers();
+}
+
+if (this.enqueueMark)
+  runtest(purgeKey);
+
+function removeKey() {
+  reportMarks("removeKey start: ");
+
+  const m = new WeakMap();
+  const vals = {};
+  vals.key = Object.create(null);
+  vals.val = Object.create(null);
+  m.set(vals.key, vals.val);
+
+  minorgc();
+
+  addMarkObservers([m, vals.key, vals.val]);
+
+  enqueueMark(m);
+  enqueueMark("yield");
+
+  startGCMarking();
+  reportMarks("first: ");
+  var marks = getMarks();
+  assertEq(marks[0], "black", "map is black");
+  assertEq(marks[1], "unmarked", "key not marked yet");
+  assertEq(marks[2], "unmarked", "value not marked yet");
+  m.delete(vals.key);
+
+  finishgc(); // Finish the GC
+  reportMarks("done: ");
+  marks = getMarks();
+  assertEq(marks[0], "black", "map is black");
+  assertEq(marks[1], "black", "key is black");
+  assertEq(marks[2], "black", "value is black");
+
+  // Do it again, but this time, remove all other roots.
+  m.set(vals.key, vals.val);
+  vals.key = vals.val = null;
+  startgc(10000);
+  while (gcstate() !== "Mark") {
+    gcslice(100000);
+  }
+  marks = getMarks();
+  assertEq(marks[0], "black", "map is black");
+  assertEq(marks[1], "unmarked", "key not marked yet");
+  assertEq(marks[2], "unmarked", "value not marked yet");
+
+  // This was meant to test the weakmap deletion barrier, which would remove
+  // the key from weakkeys. Unfortunately, JS-exposed WeakMaps now have a read
+  // barrier on lookup that marks the key, and deletion requires a lookup.
+  m.delete(nondeterministicGetWeakMapKeys(m)[0]);
+
+  finishgc();
+  marks = getMarks();
+  assertEq(marks[0], "black", "map is black");
+  assertEq(marks[1], "black", "key was blackened by lookup read barrier during deletion");
+  assertEq(marks[2], "black", "value is black because map and key are black");
+
+  clearMarkQueue();
+  clearMarkObservers();
+}
+
+if (this.enqueueMark)
+  runtest(removeKey);
+
+// Test:
+//   1. mark the map
+//     - that inserts the delegate into weakKeys
+//   2. nuke the CCW key
+//     - removes the delegate from weakKeys
+//   3. mark the key
+//   4. enter weak marking mode
+//
+// The problem it's attempting to recreate is that entering weak marking mode
+// will no longer mark the value, because there's no delegate to trigger it,
+// and the key was not added to weakKeys (because at the time the map was
+// scanned, the key had a delegate, so it was added to weakKeys instead.)
+function nukeMarking() {
+  const g1 = newGlobal({newCompartment: true});
+
+  const vals = {};
+  vals.map = new WeakMap();
+  vals.key = g1.eval("Object.create(null)");
+  vals.val = Object.create(null);
+  vals.map.set(vals.key, vals.val);
+  vals.val = null;
+  gc();
+
+  // Set up the sequence of marking events.
+  enqueueMark(vals.map);
+  enqueueMark("yield");
+  // We will nuke the key's delegate here.
+  enqueueMark(vals.key);
+  enqueueMark("enter-weak-marking-mode");
+
+  // Okay, run through the GC now.
+  startgc(1000000);
+  while (gcstate() !== "Mark") {
+    gcslice(100000);
+  }
+  assertEq(gcstate(), "Mark", "expected to yield after marking map");
+  // We should have marked the map and then yielded back here.
+  nukeCCW(vals.key);
+  // Finish up the GC.
+  gcslice();
+
+  clearMarkQueue();
+}
+
+if (this.enqueueMark)
+  runtest(nukeMarking);
+
+function transplantMarking() {
+  const g1 = newGlobal({newCompartment: true});
+
+  const vals = {};
+  vals.map = new WeakMap();
+  let {object, transplant} = transplantableObject();
+  vals.key = object;
+  object = null;
+  vals.val = Object.create(null);
+  vals.map.set(vals.key, vals.val);
+  vals.val = null;
+  gc();
+
+  // Set up the sequence of marking events.
+  enqueueMark(vals.map);
+  enqueueMark("yield");
+  // We will transplant the key here.
+  enqueueMark(vals.key);
+  enqueueMark("enter-weak-marking-mode");
+
+  // Okay, run through the GC now.
+  startgc(1000000);
+  while (gcstate() !== "Mark") {
+    gcslice(100000);
+  }
+  assertEq(gcstate(), "Mark", "expected to yield after marking map");
+  // We should have marked the map and then yielded back here.
+  transplant(g1);
+  // Finish up the GC.
+  gcslice();
+
+  clearMarkQueue();
+}
+
+if (this.enqueueMark)
+  runtest(transplantMarking);
+
+// 1. Mark the map
+//   => add delegate to weakKeys
+// 2. Mark the delegate black
+//   => do nothing because we are not in weak marking mode
+// 3. Mark the key gray
+//   => mark value gray, not that we really care
+// 4. Enter weak marking mode
+//   => black delegate darkens the key from gray to black
+function grayMarkingMapFirst() {
+  const g = newGlobal({newCompartment: true});
+  const vals = {};
+  vals.map = new WeakMap();
+  vals.key = g.eval("Object.create(null)");
+  vals.val = Object.create(null);
+  vals.map.set(vals.key, vals.val);
+
+  g.delegate = vals.key;
+  g.eval("dummy = Object.create(null)");
+  g.eval("grayRoot().push(delegate, dummy)");
+  addMarkObservers([vals.map, vals.key]);
+  g.addMarkObservers([vals.key, g.dummy]);
+  addMarkObservers([vals.val]);
+
+  gc();
+
+  enqueueMark(vals.map);
+  enqueueMark("yield"); // checkpoint 1
+
+  g.enqueueMark(vals.key);
+  enqueueMark("yield"); // checkpoint 2
+
+  vals.val = null;
+  vals.key = null;
+  g.delegate = null;
+  g.dummy = null;
+
+  const showmarks = () => {
+    print("[map,key,delegate,graydummy,value] marked " + JSON.stringify(getMarks()));
+  };
+
+  print("Starting incremental GC");
+  startGCMarking();
+  // Checkpoint 1, after marking map
+  showmarks();
+  var marks = getMarks();
+  assertEq(marks[0], "black", "map is black");
+  assertEq(marks[1], "unmarked", "key is not marked yet");
+  assertEq(marks[2], "unmarked", "delegate is not marked yet");
+
+  gcslice(100000);
+  // Checkpoint 2, after marking delegate
+  showmarks();
+  marks = getMarks();
+  assertEq(marks[0], "black", "map is black");
+  assertEq(marks[1], "unmarked", "key is not marked yet");
+  assertEq(marks[2], "black", "delegate is black");
+
+  gcslice();
+  // GC complete. Key was marked black (b/c of delegate), then gray marking saw
+  // it was already black and skipped it.
+  showmarks();
+  marks = getMarks();
+  assertEq(marks[0], "black", "map is black");
+  assertEq(marks[1], "black", "delegate marked key black because of weakmap");
+  assertEq(marks[2], "black", "delegate is still black");
+  assertEq(marks[3], "gray", "basic gray marking is working");
+  assertEq(marks[4], "black", "black map + black delegate => black value");
+
+  clearMarkQueue();
+  clearMarkObservers();
+  grayRoot().length = 0;
+  g.eval("grayRoot().length = 0");
+}
+
+if (this.enqueueMark)
+  runtest(grayMarkingMapFirst);
+
+function grayMarkingMapLast() {
+  const g = newGlobal({newCompartment: true});
+  const vals = {};
+  vals.map = new WeakMap();
+  vals.key = g.eval("Object.create(null)");
+  vals.val = Object.create(null);
+  vals.map.set(vals.key, vals.val);
+
+  vals.map2 = new WeakMap();
+  vals.key2 = g.eval("Object.create(null)");
+  vals.val2 = Object.create(null);
+  vals.map2.set(vals.key2, vals.val2);
+
+  g.delegate = vals.key;
+  g.eval("grayRoot().push(delegate)");
+  addMarkObservers([vals.map, vals.key]);
+  g.addMarkObservers([vals.key]);
+  addMarkObservers([vals.val]);
+
+  grayRoot().push(vals.key2);
+  addMarkObservers([vals.map2, vals.key2]);
+  g.addMarkObservers([vals.key2]);
+  addMarkObservers([vals.val2]);
+
+  const labels = ["map", "key", "delegate", "value", "map2", "key2", "delegate2", "value2"];
+
+  gc();
+
+  g.enqueueMark(vals.key);
+  g.enqueueMark(vals.key2);
+  enqueueMark("yield"); // checkpoint 1
+
+  vals.val = null;
+  vals.key = null;
+  g.delegate = null;
+
+  vals.map2 = null; // Important! Second map is never marked, keeps nothing alive.
+  vals.key2 = null;
+  vals.val2 = null;
+  g.delegate2 = null;
+
+  const labeledMarks = () => {
+    const info = {};
+    const marks = getMarks();
+    for (let i = 0; i < labels.length; i++)
+      info[labels[i]] = marks[i];
+    return info;
+  };
+
+  const showmarks = () => {
+    print("Marks:");
+    for (const [label, mark] of Object.entries(labeledMarks()))
+      print(`  ${label}: ${mark}`);
+  };
+
+  print("Starting incremental GC");
+  startGCMarking();
+  // Checkpoint 1, after marking key
+  showmarks();
+  var marks = labeledMarks();
+  assertEq(marks.map, "unmarked", "map is unmarked");
+  assertEq(marks.key, "unmarked", "key is not marked yet");
+  assertEq(marks.delegate, "black", "delegate is black");
+  assertEq(marks.map2, "unmarked", "map2 is unmarked");
+  assertEq(marks.key2, "unmarked", "key2 is not marked yet");
+  assertEq(marks.delegate2, "black", "delegate2 is black");
+
+  gcslice();
+  // GC complete. When entering weak marking mode, black delegate propagated to
+  // key.
+  showmarks();
+  marks = labeledMarks();
+  assertEq(marks.map, "black", "map is black");
+  assertEq(marks.key, "black", "delegate marked key black because of weakmap");
+  assertEq(marks.delegate, "black", "delegate is still black");
+  assertEq(marks.value, "black", "black map + black delegate => black value");
+  assertEq(marks.map2, "dead", "map2 is dead");
+  assertEq(marks.key2, "gray", "key2 marked gray, map2 had no effect");
+  assertEq(marks.delegate2, "black", "delegate artificially marked black via mark queue");
+  assertEq(marks.value2, "dead", "dead map + black delegate => dead value");
+
+  clearMarkQueue();
+  clearMarkObservers();
+  grayRoot().length = 0;
+  g.eval("grayRoot().length = 0");
+
+  return vals; // To prevent the JIT from optimizing out vals.
+}
+
+if (this.enqueueMark)
+  runtest(grayMarkingMapLast);
+
+function grayMapKey() {
+  const vals = {};
+  vals.m = new WeakMap();
+  vals.key = Object.create(null);
+  vals.val = Object.create(null);
+  vals.m.set(vals.key, vals.val);
+
+  // Maps are allocated black, so we won't be able to mark it gray during the
+  // first GC.
+  gc();
+
+  addMarkObservers([vals.m, vals.key, vals.val]);
+
+  // Wait until we can mark gray (ie, sweeping). Mark the map gray and yield.
+  // This should happen all in one slice.
+  enqueueMark("set-color-gray");
+  enqueueMark(vals.m);
+  enqueueMark("unset-color");
+  enqueueMark("yield");
+
+  // Make the weakmap no longer reachable from the roots, so we can mark it
+  // gray.
+  vals.m = null;
+
+  enqueueMark(vals.key);
+  enqueueMark("yield");
+
+  vals.key = vals.val = null;
+
+  startGCMarking();
+  assertEq(getMarks().join("/"), "gray/unmarked/unmarked",
+           "marked the map gray");
+
+  gcslice(100000);
+  assertEq(getMarks().join("/"), "gray/black/unmarked",
+           "key is now marked black");
+
+  finishgc(); // Finish the GC
+
+  assertEq(getMarks().join("/"), "gray/black/gray",
+           "at end: black/gray => gray");
+
+  clearMarkQueue();
+  clearMarkObservers();
+}
+
+if (this.enqueueMark)
+  runtest(grayMapKey);
+
+function grayKeyMap() {
+  const vals = {};
+  vals.m = new WeakMap();
+  vals.key = Object.create(null);
+  vals.val = Object.create(null);
+  vals.m.set(vals.key, vals.val);
+
+  addMarkObservers([vals.m, vals.key, vals.val]);
+
+  enqueueMark(vals.key);
+  enqueueMark("yield");
+
+  // Wait until we are gray marking.
+  enqueueMark("set-color-gray");
+  enqueueMark(vals.m);
+  enqueueMark("unset-color");
+  enqueueMark("yield");
+
+  enqueueMark("set-color-black");
+  enqueueMark(vals.m);
+  enqueueMark("unset-color");
+
+  // Make the weakmap no longer reachable from the roots, so we can mark it
+  // gray.
+  vals.m = null;
+
+  vals.key = vals.val = null;
+
+  // Only mark this zone, to avoid interference from other tests that may have
+  // created additional zones.
+  schedulezone(vals);
+
+  startGCMarking();
+  // getMarks() returns map/key/value
+  reportMarks("1: ");
+  assertEq(getMarks().join("/"), "unmarked/black/unmarked",
+           "marked key black");
+
+  // We always yield before sweeping (in the absence of zeal), so we will see
+  // the unmarked state another time.
+  gcslice(100000);
+  reportMarks("2: ");
+  assertEq(getMarks().join("/"), "unmarked/black/unmarked",
+           "marked key black, yield before sweeping");
+
+  gcslice(100000);
+  reportMarks("3: ");
+  assertEq(getMarks().join("/"), "gray/black/gray",
+           "marked the map gray, which marked the value when map scanned");
+
+  finishgc(); // Finish the GC
+  reportMarks("4: ");
+  assertEq(getMarks().join("/"), "black/black/black",
+           "further marked the map black, so value should also be blackened");
+
+  clearMarkQueue();
+  clearMarkObservers();
+}
+
+if (this.enqueueMark)
+  runtest(grayKeyMap);
+
+// Cause a key to be marked black *during gray marking*, by first marking a
+// delegate black, then marking the map and key gray. When the key is scanned,
+// it should be seen to be a CCW of a black delegate and so should itself be
+// marked black.
+//
+// Note that this is currently buggy -- the key will be marked because the
+// delegate is marked, but the color won't be taken into account. So the key
+// will be marked gray (or rather, it will see that it's already gray.) The bad
+// behavior this would cause is if:
+//
+//  1. You wrap an object in a CCW and use it as a weakmap key to some
+//     information.
+//  2. You keep a strong reference to the object (in its compartment).
+//  3. The only references to the CCW are gray, and are in fact part of a cycle.
+//  4. The CC runs and discards the CCW.
+//  5. You look up the object in the weakmap again. This creates a new wrapper
+//     to use as a key. It is not in the weakmap, so the information you stored
+//     before is not found. (It may have even been collected, if you had no
+//     other references to it.)
+//
+function blackDuringGray() {
+  const g = newGlobal({newCompartment: true});
+  const vals = {};
+  vals.map = new WeakMap();
+  vals.key = g.eval("Object.create(null)");
+  vals.val = Object.create(null);
+  vals.map.set(vals.key, vals.val);
+
+  g.delegate = vals.key;
+  addMarkObservers([vals.map, vals.key]);
+  g.addMarkObservers([vals.key]);
+  addMarkObservers([vals.val]);
+  // Mark observers: map, key, delegate, value
+
+  gc();
+
+  g.enqueueMark(vals.key); // Mark the delegate black
+  enqueueMark("yield"); // checkpoint 1
+
+  // Mark the map gray. This will scan through all entries, find our key, and
+  // mark it black because its delegate is black.
+  enqueueMark("set-color-gray");
+  enqueueMark(vals.map); // Mark the map gray
+
+  vals.map = null;
+  vals.val = null;
+  vals.key = null;
+  g.delegate = null;
+
+  const showmarks = () => {
+    print("[map,key,delegate,value] marked " + JSON.stringify(getMarks()));
+  };
+
+  print("Starting incremental GC");
+  startGCMarking();
+  // Checkpoint 1, after marking delegate black
+  showmarks();
+  var marks = getMarks();
+  assertEq(marks[0], "unmarked", "map is not marked yet");
+  assertEq(marks[1], "unmarked", "key is not marked yet");
+  assertEq(marks[2], "black", "delegate is black");
+  assertEq(marks[3], "unmarked", "values is not marked yet");
+
+  finishgc();
+  showmarks();
+  marks = getMarks();
+  assertEq(marks[0], "gray", "map is gray");
+  assertEq(marks[1], "gray", "delegate marks key but map is gray, so key gets gray");
+  assertEq(marks[2], "black", "delegate is still black");
+  assertEq(marks[3], "gray", "gray map + gray key => gray value");
+
+  clearMarkQueue();
+  clearMarkObservers();
+  grayRoot().length = 0;
+  g.eval("grayRoot().length = 0");
+}
+
+if (this.enqueueMark)
+  runtest(blackDuringGray);