1 files changed, 133 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/gc/compartment-revived-gc.js b/js/src/jit-test/tests/gc/compartment-revived-gc.js
new file mode 100644
index 0000000000..881f4a622a
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+++ b/js/src/jit-test/tests/gc/compartment-revived-gc.js
@@ -0,0 +1,133 @@
+// Test 'compartment revived' GCs, where we do an extra GC if there are
+// compartments which we expected to die but were kept alive.
+
+// A global used as the destination for transplants.
+let transplantTargetGlobal = newGlobal();
+
+function didCompartmentRevivedGC() {
+  return performance.mozMemory.gc.lastStartReason === "COMPARTMENT_REVIVED";
+}
+
+function compartmentCount() {
+  let r = performance.mozMemory.gc.compartmentCount;
+  return r;
+}
+
+function startIncrementalGC() {
+  startgc(1);
+  while (gcstate() === "Prepare") {
+    gcslice(100, {dontStart: true});
+  }
+  assertEq(gcstate(), "Mark");
+}
+
+function finishIncrementalGC() {
+  while (gcstate() !== "NotActive") {
+    gcslice(100, {dontStart: true});
+  }
+  assertEq(gcstate(), "NotActive");
+}
+
+// Create a new compartment and global and return the global.
+function createCompartment() {
+  return newGlobal({newCompartment: true});
+}
+
+// Create a transplantable object and create a wrapper to it from a new
+// compartment. Return a function to transplant the target object.
+function createTransplantableWrapperTarget(wrapperGlobal) {
+  let {object: target, transplant} = transplantableObject();
+  wrapperGlobal.wrapper = target;
+  return transplant;
+}
+
+// Transplant an object to a new global by calling the transplant
+// function. This remaps all wrappers pointing to the target object,
+// potentially keeping dead compartments alive.
+function transplantTargetAndRemapWrappers(transplant) {
+  transplant(transplantTargetGlobal);
+}
+
+// Test no compartment revived GC triggered in normal cases.
+function testNormal() {
+  gc();
+  assertEq(didCompartmentRevivedGC(), false);
+
+  startIncrementalGC();
+  finishIncrementalGC();
+  assertEq(didCompartmentRevivedGC(), false);
+
+  let initialCount = compartmentCount();
+  createCompartment();
+  startIncrementalGC();
+  finishIncrementalGC();
+  assertEq(compartmentCount(), initialCount);
+}
+
+// Test compartment revived GC is triggered by wrapper remapping.
+function testCompartmentRevived1() {
+  let initialCount = compartmentCount();
+  let compartment = createCompartment();
+  let transplant = createTransplantableWrapperTarget(compartment);
+  compartment = null;
+
+  startIncrementalGC();
+  transplantTargetAndRemapWrappers(transplant);
+  finishIncrementalGC();
+
+  assertEq(didCompartmentRevivedGC(), true);
+  assertEq(compartmentCount(), initialCount);
+}
+
+// Test no compartment revived GC is triggered for compartments transitively
+// kept alive by black roots.
+function testCompartmentRevived2() {
+  let initialCount = compartmentCount();
+  let compartment = createCompartment();
+  let transplant = createTransplantableWrapperTarget(compartment);
+  let liveCompartment = createCompartment();
+  liveCompartment.wrapper = compartment;
+  compartment = null;
+
+  startIncrementalGC();
+  transplantTargetAndRemapWrappers(transplant);
+  finishIncrementalGC();
+
+  assertEq(didCompartmentRevivedGC(), false);
+  assertEq(compartmentCount(), initialCount + 2);
+
+  liveCompartment = null;
+  gc();
+
+  assertEq(compartmentCount(), initialCount);
+}
+
+// Test no compartment revived GC is triggered for compartments transitively
+// kept alive by gray roots.
+function testCompartmentRevived3() {
+  let initialCount = compartmentCount();
+  let compartment = createCompartment();
+  let transplant = createTransplantableWrapperTarget(compartment);
+  let liveCompartment = createCompartment();
+  liveCompartment.wrapper = compartment;
+  liveCompartment.eval('grayRoot()[0] = this');
+  liveCompartment = null;
+  gc();
+
+  startIncrementalGC();
+  transplantTargetAndRemapWrappers(transplant);
+  finishIncrementalGC();
+
+  assertEq(didCompartmentRevivedGC(), false);
+  assertEq(compartmentCount(), initialCount + 2);
+
+  // There's no easy way to clear gray roots for a compartment we don't have
+  // any reference to.
+}
+
+gczeal(0);
+
+testNormal();
+testCompartmentRevived1();
+testCompartmentRevived2();
+testCompartmentRevived3();