1133196 - Assertion failure: frame.isDebuggee(), at Debugger.cpp:1987

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jan de Mooij [:jandem]]

Test below asserts (inbound revision 4d4b564c9d84, 32-bit OS X), even with --no-baseline.

var g = newGlobal();
g.parent = this;
g.eval("(" + function() {
    var dbg = new Debugger(parent);
    dbg.onExceptionUnwind = function(frame) {
        frame.older.onStep = function() {}
    };
} + ")()");
function f() {
    (function inner(arr) {
        inner(arr.map);
    })([]);
}
f();

Comment 1

[Shu-yu Guo [:shu]]

Interesting. The immediate cause of this is that Debugger.Frame.onStep doesn't trigger script-wide recompilation, since it's a Debugger.Frame API.

But! Due to crappy historical reasons, the "step mode" is a flag on the DebugScript, which is also the thing that keeps breakpoints. JSScript::isDebuggee returns true if the script has a DebugScript at all. If this doesn't require an immediate fix, I'm going to try to move the "step mode" flag off DebugScript and into and InterpreterFrame and BaselineFrame.

Comment 2

[Shu-yu Guo [:shu]]

"crappy historical reasons" above being JSD1.

Comment 3

[Shu-yu Guo [:shu]]

Attachment: Ensure script observability when setting Debugger.Frame.onStep.

I take back my previous comment. With the way call toggling works on baseline
scripts right now, it's better to make the whole script observable.

Jan, I think Jim is backed up on reviews. This is a Debugger-internal change,
but is easy enough to review if you trust the functions to do what their names
say.

Comment 4

[Jan de Mooij [:jandem]]

Comment on attachment 8568304 [details] [diff] [review]
Ensure script observability when setting Debugger.Frame.onStep.

Review of attachment 8568304 [details] [diff] [review]:
-----------------------------------------------------------------

LGTM, sorry for the delay.

Comment 5

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/c40a8aba7b4d