637603 - Turn on extended JNI checking for debug builds

Status: NEW

(GeckoView :: General, defect, P3)

Description

[Josh Matthews [:jdm]]

According to http://www.milk.com/kodebase/dalvik-docs-mirror/docs/jni-tips.html, if you turn on -Xcheck:jni, you get these extra correctness checks:

*    Check for null pointers where not allowed.
*    Verify argument type correctness (jclass is a class object, jfieldID points to field data, jstring is a java.lang.String).
*    Field type correctness, e.g. don't store a HashMap in a String field.
*    Ensure jmethodID is appropriate when making a static or virtual method call.
*    Check to see if an exception is pending on calls where pending exceptions are not legal.
*    Check for calls to inappropriate functions between Critical get/release calls.
*    Check that JNIEnv structs aren't being shared between threads.
*    Make sure local references aren't used outside their allowed lifespan.
*    UTF-8 strings contain only valid "modified UTF-8" data.

This sounds like it would be nice to get a clean bill of health on all these issues.

Comment 1

[Brad Lassey [:blassey] (use needinfo?)]

is there any performance impact with this flag?

Comment 2

[David Lawrence [:dkl]]

Moving all open Core::Widget: Android bugs to GeckoView::General (then the triage owner of GeckoView will decide which ones are valuable and which ones should be closed).

Comment 3

[Emily Toop (:fluffyemily)]

This might be worth investigating to see if this is still a thing.