Last Comment Bug 703645 - rm SRC_TRACE
: rm SRC_TRACE
Status: RESOLVED FIXED
:
Product: Core
Classification: Components
Component: JavaScript Engine (show other bugs)
: unspecified
: x86_64 Linux
: -- normal (vote)
: mozilla11
Assigned To: general
:
Mentors:
Depends on:
Blocks:
  Show dependency treegraph
 
Reported: 2011-11-18 10:21 PST by Luke Wagner [:luke]
Modified: 2011-12-16 05:43 PST (History)
4 users (show)
Ms2ger: in‑testsuite-
See Also:
Crash Signature:
(edit)
QA Whiteboard:
Iteration: ---
Points: ---
Has Regression Range: ---
Has STR: ---


Attachments
rm SRC_TRACE (7.35 KB, patch)
2011-11-18 10:21 PST, Luke Wagner [:luke]
jwalden+bmo: review+
Details | Diff | Review

Description Luke Wagner [:luke] 2011-11-18 10:21:48 PST
Created attachment 575504 [details] [diff] [review]
rm SRC_TRACE

Not because the tracer is going to be removed (bug 698201 doesn't touch SRC_TRACE), but because it seems to be unused save a single tracer-unrelated use for decompiling do loops which should just use SRC_WHILE.  It's hard to be sure because of all the covert ways of getting to this stuff, but js/jit-tests seem to pass.  Gary, do you suppose you could give this patch a little fuzzing?
Comment 1 Gary Kwong [:gkw] [:nth10sd] 2011-11-18 17:47:55 PST
> js/jit-tests seem to pass.  Gary, do you suppose you could give this patch a
> little fuzzing?

Yeah, this seems to hold up fine after a couple of minutes' fuzzing, it doesn't seem to immediately blow anything up... yet. (hopefully not ever)
Comment 2 Jeff Walden [:Waldo] (remove +bmo to email) 2011-11-30 15:24:51 PST
Comment on attachment 575504 [details] [diff] [review]
rm SRC_TRACE

Review of attachment 575504 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/frontend/BytecodeEmitter.cpp
@@ +5986,5 @@
>          noteIndex = NewSrcNote(cx, bce, SRC_WHILE);
>          if (noteIndex < 0 || Emit1(cx, bce, JSOP_NOP) < 0)
>              return JS_FALSE;
>  
> +        noteIndex2 = NewSrcNote(cx, bce, SRC_WHILE);

Why does this need two while notes in a row?
Comment 3 Luke Wagner [:luke] 2011-11-30 16:20:19 PST
(In reply to Jeff Walden (remove +bmo to email) from comment #2)
> Why does this need two while notes in a row?

While loops need two offsets.  Here is the use:
http://hg.mozilla.org/mozilla-central/file/87da67ee3e59/js/src/jsopcode.cpp#l2417
Comment 4 Jeff Walden [:Waldo] (remove +bmo to email) 2011-11-30 16:35:03 PST
Comment on attachment 575504 [details] [diff] [review]
rm SRC_TRACE

Review of attachment 575504 [details] [diff] [review]:
-----------------------------------------------------------------

What a mess.

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