com.google.inject.internal.aop.FastClass Maven / Gradle / Ivy
/*
* Copyright (C) 2020 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.inject.internal.aop;
import static com.google.inject.internal.BytecodeGen.FASTCLASS_BY_GUICE_MARKER;
import static com.google.inject.internal.aop.BytecodeTasks.box;
import static com.google.inject.internal.aop.BytecodeTasks.unpackArguments;
import static java.lang.reflect.Modifier.FINAL;
import static java.lang.reflect.Modifier.PRIVATE;
import static java.lang.reflect.Modifier.PUBLIC;
import static java.lang.reflect.Modifier.STATIC;
import static org.objectweb.asm.ClassWriter.COMPUTE_MAXS;
import static org.objectweb.asm.Opcodes.ACC_SUPER;
import static org.objectweb.asm.Opcodes.ACONST_NULL;
import static org.objectweb.asm.Opcodes.ALOAD;
import static org.objectweb.asm.Opcodes.ARETURN;
import static org.objectweb.asm.Opcodes.CHECKCAST;
import static org.objectweb.asm.Opcodes.DUP;
import static org.objectweb.asm.Opcodes.GETFIELD;
import static org.objectweb.asm.Opcodes.H_NEWINVOKESPECIAL;
import static org.objectweb.asm.Opcodes.ILOAD;
import static org.objectweb.asm.Opcodes.INVOKEINTERFACE;
import static org.objectweb.asm.Opcodes.INVOKESPECIAL;
import static org.objectweb.asm.Opcodes.INVOKESTATIC;
import static org.objectweb.asm.Opcodes.INVOKEVIRTUAL;
import static org.objectweb.asm.Opcodes.NEW;
import static org.objectweb.asm.Opcodes.PUTFIELD;
import static org.objectweb.asm.Opcodes.PUTSTATIC;
import static org.objectweb.asm.Opcodes.RETURN;
import static org.objectweb.asm.Opcodes.V1_8;
import java.lang.invoke.MethodHandle;
import java.lang.reflect.Constructor;
import java.lang.reflect.Executable;
import java.lang.reflect.Method;
import java.util.Collection;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Handle;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Type;
/**
* Generates fast-classes.
*
* Each fast-class has a single constructor that takes an index. It also has an instance method
* that takes a context object and an array of argument objects which it combines with the index to
* call the shared static trampoline. Each fast-class instance therefore acts like a bound invoker
* to the appropriate constructor or method of the host class.
*
*
A handle to the fast-class constructor is used as the invoker table, mapping index to invoker.
*
*
Fast-classes have the following pseudo-Java structure:
*
*
* public final class HostClass$$FastClassByGuice
* implements BiFunction // each fast-class instance represents a bound invoker
* {
* private final int index; // the bound trampoline index
*
* public HostClass$$FastClassByGuice(int index) {
* this.index = index;
* }
*
* public Object apply(Object context, Object args) {
* return GUICE$TRAMPOLINE(index, context, (Object[]) args);
* }
*
* public static Object GUICE$TRAMPOLINE(int index, Object context, Object[] args) {
* switch (index) {
* case 0: {
* return new HostClass(...);
* }
* case 1: {
* return ((HostClass) context).instanceMethod(...);
* }
* case 2: {
* return HostClass.staticMethod(...);
* }
* }
* return null;
* }
* }
*
*
* @author [email protected] (Stuart McCulloch)
*/
final class FastClass extends AbstractGlueGenerator {
private static final String[] FAST_CLASS_API = {"java/util/function/BiFunction"};
private static final String INVOKERS_NAME = "GUICE$INVOKERS";
private static final String INVOKERS_DESCRIPTOR = "Ljava/lang/invoke/MethodHandle;";
private static final Type INDEX_TO_INVOKER_METHOD_TYPE =
Type.getMethodType("(I)Ljava/util/function/BiFunction;");
private static final String RAW_INVOKER_DESCRIPTOR =
"(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;";
private static final String OBJECT_ARRAY_TYPE = Type.getInternalName(Object[].class);
private final boolean hostIsInterface;
FastClass(Class hostClass) {
super(hostClass, FASTCLASS_BY_GUICE_MARKER);
hostIsInterface = hostClass.isInterface();
}
@Override
protected byte[] generateGlue(Collection members) {
ClassWriter cw = new ClassWriter(COMPUTE_MAXS);
MethodVisitor mv;
// target Java8 because that's all we need for the generated trampoline code
cw.visit(V1_8, PUBLIC | FINAL | ACC_SUPER, proxyName, null, "java/lang/Object", FAST_CLASS_API);
cw.visitSource(GENERATED_SOURCE, null);
// this shared field contains the constructor handle adapted to look like an invoker table
cw.visitField(PUBLIC | STATIC | FINAL, INVOKERS_NAME, INVOKERS_DESCRIPTOR, null, null)
.visitEnd();
setupInvokerTable(cw);
cw.visitField(PRIVATE | FINAL, "index", "I", null, null).visitEnd();
// fast-class constructor that takes an index and binds it
mv = cw.visitMethod(PUBLIC, "", "(I)V", null, null);
mv.visitCode();
mv.visitVarInsn(ALOAD, 0);
mv.visitInsn(DUP);
mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "", "()V", false);
mv.visitVarInsn(ILOAD, 1);
mv.visitFieldInsn(PUTFIELD, proxyName, "index", "I");
mv.visitInsn(RETURN);
mv.visitMaxs(0, 0);
mv.visitEnd();
// fast-class invoker function that takes a context object and argument array
mv = cw.visitMethod(PUBLIC, "apply", RAW_INVOKER_DESCRIPTOR, null, null);
mv.visitCode();
// combine bound index with context object and argument array
mv.visitVarInsn(ALOAD, 0);
mv.visitFieldInsn(GETFIELD, proxyName, "index", "I");
mv.visitVarInsn(ALOAD, 1);
mv.visitVarInsn(ALOAD, 2);
mv.visitTypeInsn(CHECKCAST, OBJECT_ARRAY_TYPE);
// call into the shared trampoline
mv.visitMethodInsn(INVOKESTATIC, proxyName, TRAMPOLINE_NAME, TRAMPOLINE_DESCRIPTOR, false);
mv.visitInsn(ARETURN);
mv.visitMaxs(0, 0);
mv.visitEnd();
generateTrampoline(cw, members);
cw.visitEnd();
return cw.toByteArray();
}
/** Generate static initializer to setup invoker table based on the fast-class constructor. */
private void setupInvokerTable(ClassWriter cw) {
MethodVisitor mv = cw.visitMethod(PRIVATE | STATIC, "", "()V", null, null);
mv.visitCode();
Handle constructorHandle = new Handle(H_NEWINVOKESPECIAL, proxyName, "", "(I)V", false);
mv.visitLdcInsn(constructorHandle);
// adapt constructor handle to make it look like an invoker table (int -> BiFunction)
mv.visitLdcInsn(INDEX_TO_INVOKER_METHOD_TYPE);
mv.visitMethodInsn(
INVOKEVIRTUAL,
"java/lang/invoke/MethodHandle",
"asType",
"(Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/MethodHandle;",
false);
mv.visitFieldInsn(PUTSTATIC, proxyName, INVOKERS_NAME, INVOKERS_DESCRIPTOR);
mv.visitInsn(RETURN);
mv.visitMaxs(0, 0);
mv.visitEnd();
}
@Override
protected void generateConstructorInvoker(MethodVisitor mv, Constructor constructor) {
mv.visitTypeInsn(NEW, hostName);
mv.visitInsn(DUP);
// fast-class constructor invokers don't use the context object
unpackArguments(mv, constructor.getParameterTypes());
mv.visitMethodInsn(
INVOKESPECIAL, hostName, "", Type.getConstructorDescriptor(constructor), false);
}
@Override
protected void generateMethodInvoker(MethodVisitor mv, Method method) {
int invokeOpcode;
if ((method.getModifiers() & STATIC) == 0) {
// context object is the instance whose method we want to call
mv.visitVarInsn(ALOAD, 1);
mv.visitTypeInsn(CHECKCAST, hostName);
invokeOpcode = hostIsInterface ? INVOKEINTERFACE : INVOKEVIRTUAL;
} else {
// fast-class static method invokers don't use the context object
invokeOpcode = INVOKESTATIC;
}
unpackArguments(mv, method.getParameterTypes());
mv.visitMethodInsn(
invokeOpcode,
hostName,
method.getName(),
Type.getMethodDescriptor(method),
hostIsInterface);
Class returnType = method.getReturnType();
if (returnType == void.class) {
mv.visitInsn(ACONST_NULL);
} else if (returnType.isPrimitive()) {
box(mv, Type.getType(returnType));
}
}
@Override
protected MethodHandle lookupInvokerTable(Class glueClass) throws Throwable {
return (MethodHandle) glueClass.getField(INVOKERS_NAME).get(null);
}
}