import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_deepStack_01.js

@@ -0,0 +1,70 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test that we can save a core dump with very deep allocation stacks and read
+// it back into a HeapSnapshot.
+
+function stackDepth(stack) {
+  return stack ? 1 + stackDepth(stack.parent) : 0;
+}
+
+function run_test() {
+  // Create a Debugger observing a debuggee's allocations.
+  const debuggee = new Cu.Sandbox(null);
+  const dbg = new Debugger(debuggee);
+  dbg.memory.trackingAllocationSites = true;
+
+  // Allocate some objects in the debuggee that will have their allocation
+  // stacks recorded by the Debugger.
+
+  debuggee.eval("this.objects = []");
+  debuggee.eval(
+    (function recursiveAllocate(n) {
+      if (n <= 0)
+        return;
+
+      // Make sure to recurse before pushing the object so that when TCO is
+      // implemented sometime in the future, it doesn't invalidate this test.
+      recursiveAllocate(n - 1);
+      this.objects.push({});
+    }).toString()
+  );
+  debuggee.eval("recursiveAllocate = recursiveAllocate.bind(this);");
+  debuggee.eval("recursiveAllocate(200);");
+
+  // Now save a snapshot that will include the allocation stacks and read it
+  // back again.
+
+  const filePath = ChromeUtils.saveHeapSnapshot({ runtime: true });
+  ok(true, "Should be able to save a snapshot.");
+
+  const snapshot = ChromeUtils.readHeapSnapshot(filePath);
+  ok(snapshot, "Should be able to read a heap snapshot");
+  ok(snapshot instanceof HeapSnapshot, "Should be an instanceof HeapSnapshot");
+
+  const report = snapshot.takeCensus({
+    breakdown: { by: "allocationStack",
+                 then: { by: "count", bytes: true, count: true },
+                 noStack: { by: "count", bytes: true, count: true }
+               }
+  });
+
+  // Keep this synchronized with `HeapSnapshot::MAX_STACK_DEPTH`!
+  const MAX_STACK_DEPTH = 60;
+
+  let foundStacks = false;
+  report.forEach((v, k) => {
+    if (k === "noStack") {
+      return;
+    }
+
+    foundStacks = true;
+    const depth = stackDepth(k);
+    dumpn("Stack depth is " + depth);
+    ok(depth <= MAX_STACK_DEPTH,
+       "Every stack should have depth less than or equal to the maximum stack depth");
+  });
+  ok(foundStacks);
+
+  do_test_finished();
+}