Mozilla Bugzilla 上已经有了对应的 meta bug. 具体的实现可能需要再等一到两个月.

Nicolas B. Pierron [:nbp] 2015-07-30 08:05:23 PDT This is a meta bug to add Code Coverage for JavaScript code executed in SpiderMonkey. We have multiple reasons to do that:

The most important is to support release management team, by producing Code Coverage information over executed JavaScript code, and producing gcov-like data files. This would help improve the quality of Firefox, and help evaluate the quality of our tests to accept/refuse new features.

The second reason is to expose this information to the dev-tools, such that JavaScript developers do not have to instrument their code to have code coverage results within the dev-tools.

The third, if the overhead is neglectable, is to make use of the same information to improve IonMonkey register allocation and removal of unused basic blocks ahead of time.