1060668 - [jsdbg2] Debugger.prototype.onEnterFrame is overbroad

Status: NEW

(Core :: JavaScript Engine, defect)

Description

[Jim Blandy :jimb]

The Debugger.prototype.onEnterFrame hook observes many more invocations than we actually want it to. Since D.p.onEnterFrame gets called for *any* new frame pushed, this forces the SpiderMonkey JITs to generate debug prologues for all scripts observed by a Debugger that has an onEnterFrame hook set. But in practice, we usually have a *specific* frame whose calls we want to observe.

Instead of the present Debugger.prototype.onEnterFrame, we should have:

- Debugger.prototype.onEnterFirstFrame, which fires when we first enter JS with an empty stack (or perhaps when we enter JS with a new Script Entry reason?); and

- Debugger.Frame.prototype.onInvoke, which fires when 'this' frame calls another function or calls eval.

This would let all the scripts not actually being executed remain unchanged.