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8318457: Use prefix-less prepend methods directly to reduce branches in String concat expressions

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Reviewed-by: jlaskey, liach
This commit is contained in:
Claes Redestad 2023-10-20 11:37:07 +00:00
parent 71c99a0e59
commit fe52917054
3 changed files with 35 additions and 30 deletions
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31
src/java.base/share/classes/java/lang/invoke/StringConcatFactory.java
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@ -700,19 +700,12 @@ public final class StringConcatFactory {
// Simple prependers, single argument. May be used directly or as a
// building block for complex prepender combinators.
private static MethodHandle prepender(String prefix, Class<?> cl) {
MethodHandle prepend;
int idx = classIndex(cl);
if (prefix == null) {
prepend = NULL_PREPENDERS[idx];
if (prepend == null) {
NULL_PREPENDERS[idx] = prepend = MethodHandles.insertArguments(
prepender(cl), 3, (String)null);
}
if (prefix == null || prefix.isEmpty()) {
return noPrefixPrepender(cl);
} else {
prepend = MethodHandles.insertArguments(
return MethodHandles.insertArguments(
prepender(cl), 3, prefix);
}
return prepend;
}
private static MethodHandle prepender(Class<?> cl) {
@ -729,6 +722,20 @@ public final class StringConcatFactory {
return prepend;
}
private static MethodHandle noPrefixPrepender(Class<?> cl) {
int idx = classIndex(cl);
MethodHandle prepend = NO_PREFIX_PREPENDERS[idx];
if (prepend == null) {
if (idx == STRING_CONCAT_ITEM) {
cl = FormatConcatItem.class;
}
NO_PREFIX_PREPENDERS[idx] = prepend = JLA.stringConcatHelper("prepend",
methodType(long.class, long.class, byte[].class,
Wrapper.asPrimitiveType(cl))).rebind();
}
return prepend;
}
private static final int INT_IDX = 0,
CHAR_IDX = 1,
LONG_IDX = 2,
@ -995,7 +1002,7 @@ public final class StringConcatFactory {
}
}
private static final @Stable MethodHandle[] NULL_PREPENDERS = new MethodHandle[TYPE_COUNT];
private static final @Stable MethodHandle[] NO_PREFIX_PREPENDERS = new MethodHandle[TYPE_COUNT];
private static final @Stable MethodHandle[] PREPENDERS = new MethodHandle[TYPE_COUNT];
private static final @Stable MethodHandle[] MIXERS = new MethodHandle[TYPE_COUNT];
private static final long INITIAL_CODER = JLA.stringConcatInitialCoder();
@ -1117,7 +1124,7 @@ public final class StringConcatFactory {
Class<?> ttype = ttypes[pos];
// (long,byte[],ttype) -> long
MethodHandle prepender = prepender(fragment.isEmpty() ? null : fragment, ttype);
MethodHandle prepender = prepender(fragment, ttype);
// (byte[],long,ttypes...) -> String (unchanged)
mh = MethodHandles.filterArgumentsWithCombiner(mh, 1, prepender,1, 0, 2 + pos);