Remove stream usage from Symtab.lookupPackage()

[Archie Cobbs]

On Tue, Feb 21, 2023 at 6:24 PM christoph.dreis at freenet.de <
christoph.dreis at freenet.de> wrote:

> I'm currently profiling some compilation phases of internal projects and
> noticed in allocation profiles that Symtab.lookupPackage takes up ~2%
> overall. The majority of this is spent in .stream().anyMatch() usages to
> find out if the given module symbol depends on the unnamed module.
>

Straightforward patch, but it's disappointing that unrolling a Stream into
the equivalent for loop makes it noticeably faster (how much?).

This also brings up larger philosophical questions about code style vs.
performance. If using a Stream somewhere makes for more
clean/elegant/understandable code, but is slower, how to weigh the
trade-off? Maybe this has been discussed before on this list before I
joined. Maybe we should assign this bug to the hotspot group :)

On this same topic, this pattern which appears constantly in the compiler
always makes me kind of quizzical:

JCExpression expr = TreeInfo.skipParens(tree.expr);
if (expr.hasTag(APPLY)) {
    JCMethodInvocation apply = (JCMethodInvocation)expr;
    ...
}

Is instanceof really that much slower? Maybe it was once, long ago, and
this is a legacy thing?

-Archie

-- 
Archie L. Cobbs
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