Richard Guenther wrote:
> On Sat, Apr 18, 2009 at 7:01 PM, Dave Korn
> <dave.korn.cyg...@googlemail.com> wrote:
>> With the default per-thread stack size of 2MB, it crashes in
>> tree_ssa_phiprop_1(), which by the time of the crash has recursed to a depth
>> that I can actually honestly describe as "OVER 9000"! If I boost the stack
>> to
>> 4MB, I find that the recursion does actually bottom out at some point, since
>> the compile completes, but I tested at 3MB and it crashed at a recursion
>> depth
>> of 13924.
>>
>> I know that boostrapping libjava is a tough job and pretty intensive on
>> memory demands, but is this level of nesting actually to be expected, or has
>> something gone astray?
>
> Well, this is one of the usual ways of iterating over the CFG, so this
> is certainly not unexpected.
It appears to be the only pass that gets anywhere near this level of stack
usage, if I gate it off the compilation completes successfully.
> Maybe for some reason gsi is not scalarized and stack usage
> of that function is unusually high?
Yes, I suspect it's as simple as that. The function itself is
defineElements() in
libjava/classpath/gnu/javax/swing/text/html/parser/HTML_401F.java, and it's
got a huge long sequence of function calls to a function called defElement(),
each of which contain numerous constructors creating array arguments for the
call, e.g.
defElement(SUB, 0, false, false, null,
NONE
,
new String[] {
PCDATA, A, ABBR, ACRONYM,
APPLET, B, BASEFONT, BDO, BIG,
BR, BUTTON, CITE, CODE, DFN,
EM, FONT, I, IFRAME, IMG,
INPUT, KBD, LABEL, MAP, OBJECT,
Q, S, SAMP, SCRIPT, SELECT,
SMALL, SPAN, STRIKE, STRONG, SUB,
SUP, TEXTAREA, TT, U, VAR
}
,
new AttributeList[] {
attr(sID, null, null, ID, IMPLIED),
attr(CLASS, null, null, 0, IMPLIED),
attr(STYLE, null, null, 0, IMPLIED),
attr(TITLE, null, null, 0, IMPLIED),
attr(LANG, null, null, 0, IMPLIED),
attr(DIR, null, new String[] { LTR, RTL }, 0, IMPLIED),
attr(ONCLICK, null, null, 0, IMPLIED),
attr(ONDBLCLICK, null, null, 0, IMPLIED),
attr(ONMOUSEDOWN, null, null, 0, IMPLIED),
attr(ONMOUSEUP, null, null, 0, IMPLIED),
attr(ONMOUSEOVER, null, null, 0, IMPLIED),
attr(ONMOUSEMOVE, null, null, 0, IMPLIED),
attr(ONMOUSEOUT, null, null, 0, IMPLIED),
attr(ONKEYPRESS, null, null, 0, IMPLIED),
attr(ONKEYDOWN, null, null, 0, IMPLIED),
attr(ONKEYUP, null, null, 0, IMPLIED)
}
);
and that's one of the shorter examples, and this goes on for thousands of
lines, so I think I can believe that there really are that many BBs and that
level of dominator nesting. Thanks for commenting; I'll just turn up my
per-thread stack allocation and not worry about it.
cheers,
DaveK
