mirror of
https://github.com/openjdk/jdk.git
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8327247: C2 uses up to 2GB of RAM to compile complex string concat in extreme cases
Reviewed-by: mchung, shade
This commit is contained in:
Claes Redestad
parent
2b7176a55a
commit
5e2ced4b9e
2 changed files with 297 additions and 8 deletions
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@ -1,5 +1,5 @@
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/*
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* Copyright (c) 2015, 2022, Oracle and/or its affiliates. All rights reserved.
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* Copyright (c) 2015, 2024, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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@ -27,17 +27,20 @@ package java.lang.invoke;
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import jdk.internal.access.JavaLangAccess;
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import jdk.internal.access.SharedSecrets;
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import jdk.internal.javac.PreviewFeature;
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import jdk.internal.misc.VM;
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import jdk.internal.org.objectweb.asm.ClassWriter;
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import jdk.internal.org.objectweb.asm.MethodVisitor;
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import jdk.internal.util.ClassFileDumper;
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import jdk.internal.vm.annotation.Stable;
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import sun.invoke.util.Wrapper;
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import java.lang.invoke.MethodHandles.Lookup;
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import java.util.ArrayList;
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import java.util.Iterator;
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import java.util.List;
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import java.util.Objects;
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import java.util.Set;
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import static java.lang.invoke.MethodHandles.Lookup.ClassOption.STRONG;
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import static java.lang.invoke.MethodType.methodType;
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import static jdk.internal.org.objectweb.asm.Opcodes.*;
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/**
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* <p>Methods to facilitate the creation of String concatenation methods, that
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@ -98,6 +101,13 @@ import static java.lang.invoke.MethodType.methodType;
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*/
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public final class StringConcatFactory {
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private static final int HIGH_ARITY_THRESHOLD;
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static {
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String highArity = VM.getSavedProperty("java.lang.invoke.StringConcat.highArityThreshold");
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HIGH_ARITY_THRESHOLD = highArity != null ? Integer.parseInt(highArity) : 20;
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}
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/**
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* Tag used to demarcate an ordinary argument.
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*/
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@ -354,9 +364,14 @@ public final class StringConcatFactory {
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}
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try {
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return new ConstantCallSite(
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generateMHInlineCopy(concatType, constantStrings)
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.viewAsType(concatType, true));
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if (concatType.parameterCount() < HIGH_ARITY_THRESHOLD) {
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return new ConstantCallSite(
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generateMHInlineCopy(concatType, constantStrings)
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.viewAsType(concatType, true));
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} else {
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return new ConstantCallSite(
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SimpleStringBuilderStrategy.generate(lookup, concatType, constantStrings));
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}
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} catch (Error e) {
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// Pass through any error
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throw e;
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@ -1032,4 +1047,235 @@ public final class StringConcatFactory {
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// no instantiation
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}
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/**
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* Bytecode StringBuilder strategy.
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*
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* <p>This strategy emits StringBuilder chains as similar as possible
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* to what javac would. No exact sizing of parameters or estimates.
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*/
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private static final class SimpleStringBuilderStrategy {
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static final int CLASSFILE_VERSION = 52; // JDK 8
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static final String METHOD_NAME = "concat";
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// ClassFileDumper replaced java.lang.invoke.ProxyClassDumper in JDK 21
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// -- see JDK-8304846
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static final ClassFileDumper DUMPER =
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ClassFileDumper.getInstance("java.lang.invoke.StringConcatFactory.dump", "stringConcatClasses");
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/**
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* Ensure a capacity in the initial StringBuilder to accommodate all
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* constants plus this factor times the number of arguments.
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*/
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static final int ARGUMENT_SIZE_FACTOR = 4;
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static final Set<Lookup.ClassOption> SET_OF_STRONG = Set.of(STRONG);
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private SimpleStringBuilderStrategy() {
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// no instantiation
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}
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private static MethodHandle generate(Lookup lookup, MethodType args, String[] constants) throws Exception {
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String className = getClassName(lookup.lookupClass());
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ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
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cw.visit(CLASSFILE_VERSION,
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ACC_SUPER + ACC_PUBLIC + ACC_FINAL + ACC_SYNTHETIC,
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className,
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null,
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"java/lang/Object",
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null
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);
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MethodVisitor mv = cw.visitMethod(
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ACC_PUBLIC + ACC_STATIC + ACC_FINAL,
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METHOD_NAME,
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args.toMethodDescriptorString(),
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null,
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null);
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mv.visitCode();
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// Prepare StringBuilder instance
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mv.visitTypeInsn(NEW, "java/lang/StringBuilder");
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mv.visitInsn(DUP);
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int len = 0;
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for (String constant : constants) {
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if (constant != null) {
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len += constant.length();
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}
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}
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len += args.parameterCount() * ARGUMENT_SIZE_FACTOR;
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iconst(mv, len);
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mv.visitMethodInsn(
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INVOKESPECIAL,
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"java/lang/StringBuilder",
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"<init>",
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"(I)V",
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false
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);
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// At this point, we have a blank StringBuilder on stack, fill it in with .append calls.
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{
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int off = 0;
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for (int c = 0; c < args.parameterCount(); c++) {
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if (constants[c] != null) {
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mv.visitLdcInsn(constants[c]);
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sbAppend(mv, "(Ljava/lang/String;)Ljava/lang/StringBuilder;");
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}
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Class<?> cl = args.parameterType(c);
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mv.visitVarInsn(getLoadOpcode(cl), off);
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off += getParameterSize(cl);
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String desc = getSBAppendDesc(cl);
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sbAppend(mv, desc);
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}
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if (constants[constants.length - 1] != null) {
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mv.visitLdcInsn(constants[constants.length - 1]);
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sbAppend(mv, "(Ljava/lang/String;)Ljava/lang/StringBuilder;");
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}
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}
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mv.visitMethodInsn(
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INVOKEVIRTUAL,
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"java/lang/StringBuilder",
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"toString",
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"()Ljava/lang/String;",
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false
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);
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mv.visitInsn(ARETURN);
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mv.visitMaxs(-1, -1);
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mv.visitEnd();
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cw.visitEnd();
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byte[] classBytes = cw.toByteArray();
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try {
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Lookup hiddenLookup = lookup.makeHiddenClassDefiner(className, classBytes, SET_OF_STRONG, DUMPER)
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.defineClassAsLookup(true);
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Class<?> innerClass = hiddenLookup.lookupClass();
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return hiddenLookup.findStatic(innerClass, METHOD_NAME, args);
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} catch (Exception e) {
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throw new StringConcatException("Exception while spinning the class", e);
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}
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}
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private static void sbAppend(MethodVisitor mv, String desc) {
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mv.visitMethodInsn(
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INVOKEVIRTUAL,
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"java/lang/StringBuilder",
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"append",
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desc,
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false
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);
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}
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/**
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* The generated class is in the same package as the host class as
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* it's the implementation of the string concatenation for the host
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* class.
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*/
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private static String getClassName(Class<?> hostClass) {
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String name = hostClass.isHidden() ? hostClass.getName().replace('/', '_')
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: hostClass.getName();
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return name.replace('.', '/') + "$$StringConcat";
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}
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private static String getSBAppendDesc(Class<?> cl) {
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if (cl.isPrimitive()) {
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if (cl == Integer.TYPE || cl == Byte.TYPE || cl == Short.TYPE) {
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return "(I)Ljava/lang/StringBuilder;";
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} else if (cl == Boolean.TYPE) {
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return "(Z)Ljava/lang/StringBuilder;";
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} else if (cl == Character.TYPE) {
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return "(C)Ljava/lang/StringBuilder;";
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} else if (cl == Double.TYPE) {
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return "(D)Ljava/lang/StringBuilder;";
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} else if (cl == Float.TYPE) {
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return "(F)Ljava/lang/StringBuilder;";
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} else if (cl == Long.TYPE) {
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return "(J)Ljava/lang/StringBuilder;";
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} else {
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throw new IllegalStateException("Unhandled primitive StringBuilder.append: " + cl);
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}
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} else if (cl == String.class) {
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return "(Ljava/lang/String;)Ljava/lang/StringBuilder;";
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} else {
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return "(Ljava/lang/Object;)Ljava/lang/StringBuilder;";
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}
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}
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private static String getStringValueOfDesc(Class<?> cl) {
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if (cl.isPrimitive()) {
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if (cl == Integer.TYPE || cl == Byte.TYPE || cl == Short.TYPE) {
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return "(I)Ljava/lang/String;";
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} else if (cl == Boolean.TYPE) {
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return "(Z)Ljava/lang/String;";
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} else if (cl == Character.TYPE) {
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return "(C)Ljava/lang/String;";
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} else if (cl == Double.TYPE) {
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return "(D)Ljava/lang/String;";
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} else if (cl == Float.TYPE) {
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return "(F)Ljava/lang/String;";
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} else if (cl == Long.TYPE) {
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return "(J)Ljava/lang/String;";
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} else {
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throw new IllegalStateException("Unhandled String.valueOf: " + cl);
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}
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} else if (cl == String.class) {
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return "(Ljava/lang/String;)Ljava/lang/String;";
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} else {
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return "(Ljava/lang/Object;)Ljava/lang/String;";
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}
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}
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/**
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* The following method is copied from
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* org.objectweb.asm.commons.InstructionAdapter. Part of ASM: a very small
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* and fast Java bytecode manipulation framework.
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* Copyright (c) 2000-2005 INRIA, France Telecom All rights reserved.
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*/
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private static void iconst(MethodVisitor mv, final int cst) {
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if (cst >= -1 && cst <= 5) {
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mv.visitInsn(ICONST_0 + cst);
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} else if (cst >= Byte.MIN_VALUE && cst <= Byte.MAX_VALUE) {
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mv.visitIntInsn(BIPUSH, cst);
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} else if (cst >= Short.MIN_VALUE && cst <= Short.MAX_VALUE) {
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mv.visitIntInsn(SIPUSH, cst);
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} else {
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mv.visitLdcInsn(cst);
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}
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}
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private static int getLoadOpcode(Class<?> c) {
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if (c == Void.TYPE) {
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throw new InternalError("Unexpected void type of load opcode");
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}
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return ILOAD + getOpcodeOffset(c);
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}
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private static int getOpcodeOffset(Class<?> c) {
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if (c.isPrimitive()) {
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if (c == Long.TYPE) {
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return 1;
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} else if (c == Float.TYPE) {
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return 2;
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} else if (c == Double.TYPE) {
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return 3;
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}
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return 0;
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} else {
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return 4;
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}
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}
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private static int getParameterSize(Class<?> c) {
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if (c == Void.TYPE) {
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return 0;
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} else if (c == Long.TYPE || c == Double.TYPE) {
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return 2;
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}
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return 1;
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}
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}
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}
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