Bug 1293551 - Part 2: Add debug-only function to dump Promise allocation site and resolution site. r=till

js/src/jsapi.cpp

@@ -4760,6 +4760,26 @@ JS::GetPromiseResolutionSite(JS::HandleObject promise)
     return promise->as<PromiseObject>().resolutionSite();
 }
 
+#ifdef DEBUG
+JS_PUBLIC_API(void)
+JS::DumpPromiseAllocationSite(JSContext* cx, JS::HandleObject promise)
+{
+    RootedObject stack(cx, promise->as<PromiseObject>().allocationSite());
+    UniqueChars stackStr(reinterpret_cast<char*>(BuildUTF8StackString(cx, stack).get()));
+    if (stackStr.get())
+        fputs(stackStr.get(), stderr);
+}
+
+JS_PUBLIC_API(void)
+JS::DumpPromiseResolutionSite(JSContext* cx, JS::HandleObject promise)
+{
+    RootedObject stack(cx, promise->as<PromiseObject>().resolutionSite());
+    UniqueChars stackStr(reinterpret_cast<char*>(BuildUTF8StackString(cx, stack).get()));
+    if (stackStr.get())
+        fputs(stackStr.get(), stderr);
+}
+#endif
+
 JS_PUBLIC_API(JSObject*)
 JS::CallOriginalPromiseResolve(JSContext* cx, JS::HandleValue resolutionValue)
 {

js/src/jsapi.h

@@ -4436,6 +4436,14 @@ GetPromiseAllocationSite(JS::HandleObject promise);
 extern JS_PUBLIC_API(JSObject*)
 GetPromiseResolutionSite(JS::HandleObject promise);
 
+#ifdef DEBUG
+extern JS_PUBLIC_API(void)
+DumpPromiseAllocationSite(JSContext* cx, JS::HandleObject promise);
+
+extern JS_PUBLIC_API(void)
+DumpPromiseResolutionSite(JSContext* cx, JS::HandleObject promise);
+#endif
+
 /**
  * Calls the current compartment's original Promise.resolve on the original
  * Promise constructor, with `resolutionValue` passed as an argument.