From 3f2037f66bcc3e6f37b8175a747fe43fd85bf3d9 Mon Sep 17 00:00:00 2001
From: Jim Blandy <jimb@mozilla.com>
Date: Sun, 28 Jun 2015 13:11:06 -0700
Subject: [PATCH] Bug 1061909: Define a testing function to introduce easily
 traceable objects. r=fitzgen

---
 js/src/builtin/TestingFunctions.cpp           | 21 +++++++++++++++++++
 .../tests/debug/Memory-takeCensus-04.js       | 18 ++++++++--------
 .../tests/debug/Memory-takeCensus-05.js       | 12 +++++------
 3 files changed, 36 insertions(+), 15 deletions(-)

diff --git a/js/src/builtin/TestingFunctions.cpp b/js/src/builtin/TestingFunctions.cpp
index 92fd49a34a7..65eca2f204d 100644
--- a/js/src/builtin/TestingFunctions.cpp
+++ b/js/src/builtin/TestingFunctions.cpp
@@ -2494,6 +2494,20 @@ GetConstructorName(JSContext* cx, unsigned argc, Value* vp)
     return true;
 }
 
+static bool
+AllocationMarker(JSContext* cx, unsigned argc, jsval* vp)
+{
+    CallArgs args = CallArgsFromVp(argc, vp);
+
+    static const JSClass cls = { "AllocationMarker" };
+
+    RootedObject obj(cx, JS_NewObject(cx, &cls));
+    if (!obj)
+        return false;
+    args.rval().setObject(*obj);
+    return true;
+}
+
 static const JSFunctionSpecWithHelp TestingFunctions[] = {
     JS_FN_HELP("gc", ::GC, 0, 0,
 "gc([obj] | 'compartment' [, 'shrinking'])",
@@ -2911,6 +2925,13 @@ gc::ZealModeHelpText),
 "  If the given object was created with `new Ctor`, return the constructor's display name. "
 "  Otherwise, return null."),
 
+    JS_FN_HELP("allocationMarker", AllocationMarker, 0, 0,
+"allocationMarker()",
+"  Return a freshly allocated object whose [[Class]] name is\n"
+"  \"AllocationMarker\". Such objects are allocated only by calls\n"
+"  to this function, never implicitly by the system, making them\n"
+"  suitable for use in allocation tooling tests.\n"),
+
     JS_FS_HELP_END
 };
 
diff --git a/js/src/jit-test/tests/debug/Memory-takeCensus-04.js b/js/src/jit-test/tests/debug/Memory-takeCensus-04.js
index ac6593f56ac..daef676dd72 100644
--- a/js/src/jit-test/tests/debug/Memory-takeCensus-04.js
+++ b/js/src/jit-test/tests/debug/Memory-takeCensus-04.js
@@ -5,22 +5,22 @@ var g = newGlobal();
 var dbg = new Debugger(g);
 
 g.eval(`
-  function withTypedArrayOnStack(f) {
+  function withAllocationMarkerOnStack(f) {
     (function () {
-      var onStack = new Int8Array();
+      var onStack = allocationMarker();
       f();
     }())
   }
 `);
 
-assertEq("Int8Array" in dbg.memory.takeCensus().objects, false,
-         "There shouldn't exist any typed arrays in the census.");
+assertEq("AllocationMarker" in dbg.memory.takeCensus().objects, false,
+         "There shouldn't exist any allocation markers in the census.");
 
-var typedArrayCount;
-g.withTypedArrayOnStack(() => {
-  typedArrayCount = dbg.memory.takeCensus().objects.Int8Array.count;
+var allocationMarkerCount;
+g.withAllocationMarkerOnStack(() => {
+  allocationMarkerCount = dbg.memory.takeCensus().objects.AllocationMarker.count;
 });
 
-assertEq(typedArrayCount, 1,
-         "Should have one typed array in the census, because there " +
+assertEq(allocationMarkerCount, 1,
+         "Should have one allocation marker in the census, because there " +
          "was one on the stack.");
diff --git a/js/src/jit-test/tests/debug/Memory-takeCensus-05.js b/js/src/jit-test/tests/debug/Memory-takeCensus-05.js
index c03cae182e2..e83425ad06f 100644
--- a/js/src/jit-test/tests/debug/Memory-takeCensus-05.js
+++ b/js/src/jit-test/tests/debug/Memory-takeCensus-05.js
@@ -4,11 +4,11 @@
 var g = newGlobal();
 var dbg = new Debugger(g);
 
-assertEq("Int8Array" in dbg.memory.takeCensus().objects, false,
-         "There shouldn't exist any typed arrays in the census.");
+assertEq("AllocationMarker" in dbg.memory.takeCensus().objects, false,
+         "There shouldn't exist any allocation markers in the census.");
 
-this.ccw = g.eval("new Int8Array()");
+this.ccw = g.allocationMarker();
 
-assertEq(dbg.memory.takeCensus().objects.Int8Array.count, 1,
-         "Should have one typed array in the census, because there " +
-         "is one cross-compartment wrapper.");
+assertEq(dbg.memory.takeCensus().objects.AllocationMarker.count, 1,
+         "Should have one allocation marker in the census, because there " +
+         "is one cross-compartment wrapper referring to it.");