1 files changed, 99 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/saved-stacks/async-max-frame-count.js b/js/src/jit-test/tests/saved-stacks/async-max-frame-count.js
new file mode 100644
index 000000000..ebcbe13d3
--- /dev/null
+++ b/js/src/jit-test/tests/saved-stacks/async-max-frame-count.js
@@ -0,0 +1,99 @@
+// Test that async stacks are limited on recursion.
+
+const defaultAsyncStackLimit = 60;
+
+function recur(n, limit) {
+  if (n > 0) {
+    return callFunctionWithAsyncStack(function recur() {return recur(n - 1, limit)},
+                                      saveStack(limit), "Recurse");
+  }
+  return saveStack(limit);
+}
+
+function checkRecursion(n, limit) {
+  print("checkRecursion(" + uneval(n) + ", " + uneval(limit) + ")");
+
+  try {
+    var stack = recur(n, limit);
+  } catch (e) {
+    // Some platforms, like ASAN builds, can end up overrecursing. Tolerate
+    // these failures.
+    assertEq(/too much recursion/.test("" + e), true);
+    return;
+  }
+
+  // Async stacks are limited even if we didn't ask for a limit. There is a
+  // default limit on frames attached on top of any synchronous frames, and
+  // every time the limit is reached when capturing, half of the frames are
+  // truncated from the old end of the async stack.
+  if (limit == 0) {
+    // Always add one synchronous frame that is the last call to `recur`.
+    if (n + 1 < defaultAsyncStackLimit) {
+      limit = defaultAsyncStackLimit + 1;
+    } else {
+      limit = n + 2 - (defaultAsyncStackLimit / 2);
+    }
+  }
+
+  // The first `n` or `limit` frames should have `recur` as their `asyncParent`.
+  for (var i = 0; i < Math.min(n, limit); i++) {
+    assertEq(stack.functionDisplayName, "recur");
+    assertEq(stack.parent, null);
+    stack = stack.asyncParent;
+  }
+
+  // This frame should be the first call to `recur`.
+  if (limit > n) {
+    assertEq(stack.functionDisplayName, "recur");
+    assertEq(stack.asyncParent, null);
+    stack = stack.parent;
+  } else {
+    assertEq(stack, null);
+  }
+
+  // This frame should be the call to `checkRecursion`.
+  if (limit > n + 1) {
+    assertEq(stack.functionDisplayName, "checkRecursion");
+    assertEq(stack.asyncParent, null);
+    stack = stack.parent;
+  } else {
+    assertEq(stack, null);
+  }
+
+  // We should be at the top frame, which is the test script itself.
+  if (limit > n + 2) {
+    assertEq(stack.functionDisplayName, null);
+    assertEq(stack.asyncParent, null);
+    assertEq(stack.parent, null);
+  } else {
+    assertEq(stack, null);
+  }
+}
+
+// Check capturing with no limit, which should still apply a default limit.
+checkRecursion(0, 0);
+checkRecursion(1, 0);
+checkRecursion(2, 0);
+checkRecursion(defaultAsyncStackLimit - 10, 0);
+checkRecursion(defaultAsyncStackLimit, 0);
+checkRecursion(defaultAsyncStackLimit + 10, 0);
+
+// Limit of 1 frame.
+checkRecursion(0, 1);
+checkRecursion(1, 1);
+checkRecursion(2, 1);
+
+// Limit of 2 frames.
+checkRecursion(0, 2);
+checkRecursion(1, 2);
+checkRecursion(2, 2);
+
+// Limit of 3 frames.
+checkRecursion(0, 3);
+checkRecursion(1, 3);
+checkRecursion(2, 3);
+
+// Limit higher than the default limit.
+checkRecursion(defaultAsyncStackLimit + 10, defaultAsyncStackLimit + 10);
+checkRecursion(defaultAsyncStackLimit + 11, defaultAsyncStackLimit + 10);
+checkRecursion(defaultAsyncStackLimit + 12, defaultAsyncStackLimit + 10);