618422 - jstracer msvc warning in profiler code

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Robert Sayre]

> jstracer.cpp(16915) : warning C4390: ';' : empty controlled statement found; 
> is this the intent?

16904             if (prof) {
16905                 /*
16906                  * Note that execOK for the inner loop is left unchanged. So even
16907                  * if we trace the inner loop, we will never call that trace
16908                  * on its own. We'll only call it from this trace.
16909                  */
16910                 prof->profiled = true;
16911                 prof->traceOK = true;
16912                 if (IsBlacklisted(loop.top))
16913                     debug_only_printf(LC_TMProfiler, "Unblacklisting at %d\n",
16914                                       js_PCToLineNumber(cx, loop.script, loop.top));
16915                 Unblacklist(loop.script, loop.top);
16916             }

What I want to believe is that an optimized build is being compiled this way:

> if (IsBlacklisted(loop.top)); // <-- C4930

and the line number is off by one. But I am still puzzled. Doesn't that mean the code is doing this:

>  if (IsBlacklisted(loop.top)) {
>    // compiled away
>  }
>
>  Unblacklist(loop.script, loop.top);

Shouldn't we unblacklist only those loops that are blacklisted?

Comment 1

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

Attachment: fix

I'm going to blame this on the debug_only_printf macro, which I fixed. I also fixed it so that we only blacklist loops that are not already blacklisted, since that probably makes the code a little easier to read.

Comment 2

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

Comment on attachment 497301 [details] [diff] [review]
fix

This is an easy patch and a blocker. I just want to get it out of the way.

Comment 3

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

http://hg.mozilla.org/tracemonkey/rev/6545473b75b4

Comment 4

[Chris Leary [:cdleary] (not checking bugmail)]

http://hg.mozilla.org/mozilla-central/rev/6545473b75b4