703645 - rm SRC_TRACE

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Luke Wagner [:luke]]

Attachment: 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] (NOT official MoCo now)]

> 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]]

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]]

(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]]

Comment on attachment 575504 [details] [diff] [review]
rm SRC_TRACE

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

What a mess.

Comment 5

[Luke Wagner [:luke]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/5c3c5e4db3ad

Comment 6

[:Ms2ger (he/him; ⌚ UTC+1/+2)]

https://hg.mozilla.org/mozilla-central/rev/5c3c5e4db3ad