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8223454: Reduce String concatenation shapes by folding initialLengthCoder into last mixer

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Reviewed-by: jlaskey
This commit is contained in:
Claes Redestad 2019-05-09 17:28:27 +02:00
parent 08eae08a6b
commit 5d1df35fe7
1 changed files with 29 additions and 11 deletions
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40
src/java.base/share/classes/java/lang/invoke/StringConcatFactory.java
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@ -1666,25 +1666,33 @@ public final class StringConcatFactory {
// and deduce the coder from there. Arguments would be either converted to Strings
// during the initial filtering, or handled by specializations in MIXERS.
//
// The method handle shape before and after all mixers are combined in is:
// The method handle shape before all mixers are combined in is:
// (long, <args>)String = ("indexCoder", <args>)
//
// We will bind the initialLengthCoder value to the last mixer (the one that will be
// executed first), then fold that in. This leaves the shape after all mixers are
// combined in as:
// (<args>)String = (<args>)
int ac = -1;
MethodHandle mix = null;
for (RecipeElement el : recipe.getElements()) {
switch (el.getTag()) {
case TAG_CONST:
// Constants already handled in the code above
break;
case TAG_ARG:
int ac = el.getArgPos();
if (ac >= 0) {
// Compute new "index" in-place using old value plus the appropriate argument.
mh = MethodHandles.filterArgumentsWithCombiner(mh, 0, mix,
0, // old-index
1 + ac // selected argument
);
}
ac = el.getArgPos();
Class<?> argClass = ptypes[ac];
MethodHandle mix = mixer(argClass);
// Compute new "index" in-place using old value plus the appropriate argument.
mh = MethodHandles.filterArgumentsWithCombiner(mh, 0, mix,
0, // old-index
1 + ac // selected argument
);
mix = mixer(argClass);
break;
default:
@ -1692,9 +1700,19 @@ public final class StringConcatFactory {
}
}
// Insert initial length and coder value here.
// Insert the initialLengthCoder value into the final mixer, then
// fold that into the base method handle
if (ac >= 0) {
mix = MethodHandles.insertArguments(mix, 0, initialLengthCoder);
mh = MethodHandles.foldArgumentsWithCombiner(mh, 0, mix,
1 + ac // selected argument
);
} else {
// No mixer (constants only concat), insert initialLengthCoder directly
mh = MethodHandles.insertArguments(mh, 0, initialLengthCoder);
}
// The method handle shape here is (<args>).
mh = MethodHandles.insertArguments(mh, 0, initialLengthCoder);
// Apply filters, converting the arguments:
if (filters != null) {