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8222484: Specialize generation of simple String concatenation expressions

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Reviewed-by: jrose, jlaskey
This commit is contained in:
Claes Redestad 2019-04-17 00:06:38 +02:00
parent 7d9e7e1e0b
commit 781fb29580
5 changed files with 177 additions and 96 deletions
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80
src/java.base/share/classes/java/lang/invoke/StringConcatFactory.java
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -26,6 +26,7 @@
package java.lang.invoke;
import jdk.internal.misc.Unsafe;
import jdk.internal.misc.VM;
import jdk.internal.org.objectweb.asm.ClassWriter;
import jdk.internal.org.objectweb.asm.Label;
import jdk.internal.org.objectweb.asm.MethodVisitor;
@ -191,6 +192,8 @@ public final class StringConcatFactory {
*/
private static final ProxyClassesDumper DUMPER;
private static final Class<?> STRING_HELPER;
static {
// In case we need to double-back onto the StringConcatFactory during this
// static initialization, make sure we have the reasonable defaults to complete
@ -202,15 +205,20 @@ public final class StringConcatFactory {
// DEBUG = false; // implied
// DUMPER = null; // implied
Properties props = GetPropertyAction.privilegedGetProperties();
try {
STRING_HELPER = Class.forName("java.lang.StringConcatHelper");
} catch (Throwable e) {
throw new AssertionError(e);
}
final String strategy =
props.getProperty("java.lang.invoke.stringConcat");
VM.getSavedProperty("java.lang.invoke.stringConcat");
CACHE_ENABLE = Boolean.parseBoolean(
props.getProperty("java.lang.invoke.stringConcat.cache"));
VM.getSavedProperty("java.lang.invoke.stringConcat.cache"));
DEBUG = Boolean.parseBoolean(
props.getProperty("java.lang.invoke.stringConcat.debug"));
VM.getSavedProperty("java.lang.invoke.stringConcat.debug"));
final String dumpPath =
props.getProperty("java.lang.invoke.stringConcat.dumpClasses");
VM.getSavedProperty("java.lang.invoke.stringConcat.dumpClasses");
STRATEGY = (strategy == null) ? DEFAULT_STRATEGY : Strategy.valueOf(strategy);
CACHE = CACHE_ENABLE ? new ConcurrentHashMap<>() : null;
@ -1519,6 +1527,33 @@ public final class StringConcatFactory {
static MethodHandle generate(MethodType mt, Recipe recipe) throws Throwable {
// Fast-path two-argument Object + Object concatenations
if (recipe.getElements().size() == 2) {
// Two object arguments
if (mt.parameterCount() == 2 &&
!mt.parameterType(0).isPrimitive() &&
!mt.parameterType(1).isPrimitive()) {
return SIMPLE;
}
// One element is a constant
if (mt.parameterCount() == 1 && !mt.parameterType(0).isPrimitive()) {
MethodHandle mh = SIMPLE;
// Insert constant element
// First recipe element is a constant
if (recipe.getElements().get(0).getTag() == TAG_CONST &&
recipe.getElements().get(1).getTag() != TAG_CONST) {
return MethodHandles.insertArguments(mh, 0,
recipe.getElements().get(0).getValue());
} else if (recipe.getElements().get(1).getTag() == TAG_CONST &&
recipe.getElements().get(0).getTag() != TAG_CONST) {
return MethodHandles.insertArguments(mh, 1,
recipe.getElements().get(1).getValue());
}
// else... fall-through to slow-path
}
}
// Create filters and obtain filtered parameter types. Filters would be used in the beginning
// to convert the incoming arguments into the arguments we can process (e.g. Objects -> Strings).
// The filtered argument type list is used all over in the combinators below.
@ -1626,13 +1661,6 @@ public final class StringConcatFactory {
return mh;
}
@ForceInline
private static byte[] newArray(long indexCoder) {
byte coder = (byte)(indexCoder >> 32);
int index = (int)indexCoder;
return (byte[]) UNSAFE.allocateUninitializedArray(byte.class, index << coder);
}
private static MethodHandle prepender(Class<?> cl) {
return PREPENDERS.computeIfAbsent(cl, PREPEND);
}
@ -1659,16 +1687,15 @@ public final class StringConcatFactory {
}
};
private static final MethodHandle SIMPLE;
private static final MethodHandle NEW_STRING;
private static final MethodHandle NEW_ARRAY;
private static final ConcurrentMap<Class<?>, MethodHandle> PREPENDERS;
private static final ConcurrentMap<Class<?>, MethodHandle> MIXERS;
private static final long INITIAL_CODER;
static final Class<?> STRING_HELPER;
static {
try {
STRING_HELPER = Class.forName("java.lang.StringConcatHelper");
MethodHandle initCoder = lookupStatic(Lookup.IMPL_LOOKUP, STRING_HELPER, "initialCoder", long.class);
INITIAL_CODER = (long) initCoder.invoke();
} catch (Throwable e) {
@ -1678,8 +1705,9 @@ public final class StringConcatFactory {
PREPENDERS = new ConcurrentHashMap<>();
MIXERS = new ConcurrentHashMap<>();
SIMPLE = lookupStatic(Lookup.IMPL_LOOKUP, STRING_HELPER, "simpleConcat", String.class, Object.class, Object.class);
NEW_STRING = lookupStatic(Lookup.IMPL_LOOKUP, STRING_HELPER, "newString", String.class, byte[].class, long.class);
NEW_ARRAY = lookupStatic(Lookup.IMPL_LOOKUP, MethodHandleInlineCopyStrategy.class, "newArray", byte[].class, long.class);
NEW_ARRAY = lookupStatic(Lookup.IMPL_LOOKUP, STRING_HELPER, "newArray", byte[].class, long.class);
}
}
@ -1692,22 +1720,8 @@ public final class StringConcatFactory {
// no instantiation
}
private static class ObjectStringifier {
// We need some additional conversion for Objects in general, because String.valueOf(Object)
// may return null. String conversion rules in Java state we need to produce "null" String
// in this case, so we provide a customized version that deals with this problematic corner case.
private static String valueOf(Object value) {
String s;
return (value == null || (s = value.toString()) == null) ? "null" : s;
}
// Could have used MethodHandles.lookup() instead of Lookup.IMPL_LOOKUP, if not for the fact
// java.lang.invoke Lookups are explicitly forbidden to be retrieved using that API.
private static final MethodHandle INSTANCE =
lookupStatic(Lookup.IMPL_LOOKUP, ObjectStringifier.class, "valueOf", String.class, Object.class);
}
private static final MethodHandle OBJECT_INSTANCE =
lookupStatic(Lookup.IMPL_LOOKUP, STRING_HELPER, "stringOf", String.class, Object.class);
private static class FloatStringifiers {
private static final MethodHandle FLOAT_INSTANCE =
@ -1751,7 +1765,7 @@ public final class StringConcatFactory {
*/
static MethodHandle forMost(Class<?> t) {
if (!t.isPrimitive()) {
return ObjectStringifier.INSTANCE;
return OBJECT_INSTANCE;
} else if (t == float.class) {
return FloatStringifiers.FLOAT_INSTANCE;
} else if (t == double.class) {