511974 - TM: Treat "continue LABEL;" like "break;"

Status: VERIFIED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jason Orendorff [:jorendorff]]

To avoid tracing into outer loops and all sorts of craziness, we specially detect `break;` in TR::record_JSOP_GOTO and emit an unconditional exit.

We need to do the same for `continue LABEL;` where LABEL is a loop that encloses the one we're trying to record.

The patch works and the new test passes, but it messes up the goofy case where someone has pointlessly labeled a loop:

  inner:
  for (i = 0; i < 9; i++) {
      if (i == x)
          continue inner;
      ...
  }

If we care, I think the way to fix that is to skip emitting the CONT2LABEL source note for that GOTO.

Comment 1

[Jason Orendorff [:jorendorff]]

Attachment: v1

Feel free to minus if you think I should fix the silly case before checking this patch in.

Comment 2

[Jason Orendorff [:jorendorff]]

http://hg.mozilla.org/tracemonkey/rev/1c9bdf5bb1ce

Comment 3

[Robert Sayre]

http://hg.mozilla.org/mozilla-central/rev/1c9bdf5bb1ce

Comment 4

[Robert Sayre]

http://hg.mozilla.org/releases/mozilla-1.9.2/rev/43d34479b19e

Comment 5

[Bob Clary [:bc] (inactive)]

js/src/trace-test/tests/basic/testBreak.js
js/src/trace-test/tests/basic/testContinueWithLabel2.js
v 1.9.3, 1.9.2