org.pkl.thirdparty.truffle.host.HostAdapterBytecodeGenerator Maven / Gradle / Ivy
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*
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* (a) the Software, and
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package org.pkl.thirdparty.truffle.host;
import static org.pkl.thirdparty.truffle.api.impl.asm.Opcodes.ACC_FINAL;
import static org.pkl.thirdparty.truffle.api.impl.asm.Opcodes.ACC_PRIVATE;
import static org.pkl.thirdparty.truffle.api.impl.asm.Opcodes.ACC_PUBLIC;
import static org.pkl.thirdparty.truffle.api.impl.asm.Opcodes.ACC_STATIC;
import static org.pkl.thirdparty.truffle.api.impl.asm.Opcodes.ACC_SUPER;
import static org.pkl.thirdparty.truffle.api.impl.asm.Opcodes.ACC_VARARGS;
import static org.pkl.thirdparty.truffle.api.impl.asm.Opcodes.ALOAD;
import static org.pkl.thirdparty.truffle.api.impl.asm.Opcodes.H_INVOKESTATIC;
import static org.pkl.thirdparty.truffle.api.impl.asm.Opcodes.RETURN;
import static org.pkl.thirdparty.truffle.api.impl.asm.Type.BOOLEAN_TYPE;
import java.lang.annotation.Annotation;
import java.lang.invoke.CallSite;
import java.lang.invoke.MethodHandles.Lookup;
import java.lang.invoke.MethodType;
import java.lang.reflect.Constructor;
import java.lang.reflect.Executable;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import org.pkl.thirdparty.graalvm.polyglot.Value;
import org.pkl.thirdparty.truffle.api.impl.asm.ClassWriter;
import org.pkl.thirdparty.truffle.api.impl.asm.FieldVisitor;
import org.pkl.thirdparty.truffle.api.impl.asm.Handle;
import org.pkl.thirdparty.truffle.api.impl.asm.Label;
import org.pkl.thirdparty.truffle.api.impl.asm.Opcodes;
import org.pkl.thirdparty.truffle.api.impl.asm.Type;
import org.pkl.thirdparty.truffle.api.impl.asm.commons.InstructionAdapter;
/**
* Generates bytecode for a Java adapter class. Used by the {@link HostAdapterFactory}.
*
*
* For every protected or public constructor in the extended class, the adapter class will have one
* public constructor (visibility of protected constructors in the extended class is promoted to
* public).
*
* - In every case, a constructor taking a trailing {@link Value} argument preceded by original
* constructor arguments is always created on the adapter class. When such a constructor is invoked,
* the passed {@link Value}'s member functions are used to implement and/or override methods on the
* original class, dispatched by name. A single invokable member will act as the implementation for
* all overloaded methods of the same name. When methods on an adapter instance are invoked, the
* functions are invoked having the {@link Value} passed in the instance constructor as their
* receiver. Subsequent changes to the members of that {@link Value} (reassignment or removal of its
* functions) are reflected in the adapter instance; the method implementations are not bound to
* functions at constructor invocation time.
*
* {@code java.lang.Object} methods {@code equals}, {@code hashCode}, and {@code toString} can also
* be overridden. The only restriction is that since every JavaScript object already has a
* {@code toString} function through the {@code Object.prototype}, the {@code toString} in the
* adapter is only overridden if the passed object has a {@code toString} function as its own
* property, and not inherited from a prototype. All other adapter methods can be implemented or
* overridden through a prototype-inherited function of the object passed to the constructor,
* too.
* - If the original types collectively have only one abstract method, or have several of them,
* but all share the same name, the constructor(s) will check if the delegate {@link Value} is
* executable, and if so, will use the passed function as the implementation for all abstract
* methods. For consistency, any concrete methods sharing the single abstract method name will also
* be overridden by the function.
* - If the adapter being generated can have class-level overrides, constructors taking the same
* arguments as the superclass constructors are also created. These constructors simply delegate to
* the superclass constructor. They are used to create instances of the adapter class with no
* instance-level overrides.
*
*
*
* For adapter methods that return values, all the conversions supported by {@link Value#as} will be
* in effect to coerce the delegate functions' return value to the expected Java return type.
*
*
* Since we are adding a trailing argument to the generated constructors in the adapter class, they
* will never be declared as variable arity, even if the original constructor in the superclass was
* declared as variable arity.
*
*
* It is possible to create two different adapter classes: those that can have class-level
* overrides, and those that can have instance-level overrides. When
* {@link HostAdapterFactory#getAdapterClassFor} is invoked with non-null {@code classOverrides}
* parameter, an adapter class is created that can have class-level overrides, and the passed
* delegate object will be used as the implementations for its methods, just as in the above case of
* the constructor taking a script object. Note that in the case of class-level overrides, a new
* adapter class is created on every invocation, and the implementation object is bound to the
* class, not to any instance. All created instances will share these functions. If it is required
* to have both class-level overrides and instance-level overrides, the class-level override adapter
* class should be subclassed with an instance-override adapter. Since adapters delegate to super
* class when an overriding method handle is not specified, this will behave as expected. It is not
* possible to have both class-level and instance-level overrides in the same class for security
* reasons: adapter classes are defined with a protection domain of their creator code, and an
* adapter class that has both class and instance level overrides would need to have two potentially
* different protection domains: one for class-based behavior and one for instance-based behavior;
* since Java classes can only belong to a single protection domain, this could not be implemented
* securely.
*
*/
final class HostAdapterBytecodeGenerator {
// Initializer names
private static final String INIT = "";
private static final String CLASS_INIT = "";
private static final Type OBJECT_TYPE = Type.getType(Object.class);
private static final String OBJECT_TYPE_NAME = OBJECT_TYPE.getInternalName();
private static final Type POLYGLOT_VALUE_TYPE = Type.getType(Value.class);
private static final String POLYGLOT_VALUE_TYPE_DESCRIPTOR = POLYGLOT_VALUE_TYPE.getDescriptor();
private static final String BOOLEAN_TYPE_DESCRIPTOR = BOOLEAN_TYPE.getDescriptor();
private static final Type STRING_TYPE = Type.getType(String.class);
private static final Type CLASS_LOADER_TYPE = Type.getType(ClassLoader.class);
/** @see HostAdapterServices#hasMethod(Value, String) */
private static final String HAS_METHOD_NAME = "hasMethod";
private static final String HAS_METHOD_DESCRIPTOR = Type.getMethodDescriptor(BOOLEAN_TYPE, POLYGLOT_VALUE_TYPE, STRING_TYPE);
/** @see HostAdapterServices#hasOwnMethod(Value, String) */
private static final String HAS_OWN_METHOD_NAME = "hasOwnMethod";
private static final String HAS_OWN_METHOD_DESCRIPTOR = Type.getMethodDescriptor(BOOLEAN_TYPE, POLYGLOT_VALUE_TYPE, STRING_TYPE);
/** @see HostAdapterServices#getClassOverrides(ClassLoader) */
private static final String GET_CLASS_OVERRIDES_METHOD_NAME = "getClassOverrides";
private static final String GET_CLASS_OVERRIDES_METHOD_DESCRIPTOR = Type.getMethodDescriptor(POLYGLOT_VALUE_TYPE, CLASS_LOADER_TYPE);
private static final Type RUNTIME_EXCEPTION_TYPE = Type.getType(RuntimeException.class);
private static final Type THROWABLE_TYPE = Type.getType(Throwable.class);
private static final Type UNSUPPORTED_OPERATION_TYPE = Type.getType(UnsupportedOperationException.class);
/** @see HostAdapterServices#unsupported(String) */
private static final String UNSUPPORTED_METHOD_NAME = "unsupported";
private static final String UNSUPPORTED_METHOD_DESCRIPTOR = Type.getMethodDescriptor(UNSUPPORTED_OPERATION_TYPE, STRING_TYPE);
/** @see HostAdapterServices#wrapThrowable(Throwable) */
private static final String WRAP_THROWABLE_METHOD_NAME = "wrapThrowable";
private static final String WRAP_THROWABLE_METHOD_DESCRIPTOR = Type.getMethodDescriptor(RUNTIME_EXCEPTION_TYPE, THROWABLE_TYPE);
private static final String SERVICES_CLASS_TYPE_NAME = HostAdapterClassLoader.SERVICE_CLASS_NAME.replace('.', '/');
private static final String RUNTIME_EXCEPTION_TYPE_NAME = RUNTIME_EXCEPTION_TYPE.getInternalName();
private static final String ERROR_TYPE_NAME = Type.getInternalName(Error.class);
private static final String THROWABLE_TYPE_NAME = THROWABLE_TYPE.getInternalName();
private static final String CLASS_TYPE_NAME = Type.getInternalName(Class.class);
private static final String GET_CLASS_LOADER_NAME = "getClassLoader";
private static final String GET_CLASS_LOADER_DESCRIPTOR = Type.getMethodDescriptor(CLASS_LOADER_TYPE);
// ASM handle to the bootstrap method
private static final Handle BOOTSTRAP_HANDLE = new Handle(H_INVOKESTATIC, SERVICES_CLASS_TYPE_NAME, "bootstrap",
MethodType.methodType(CallSite.class, Lookup.class, String.class, MethodType.class, int.class).toMethodDescriptorString(), false);
// Keep in sync with constants in HostAdapterServices
static final int BOOTSTRAP_VALUE_INVOKE_MEMBER = 1 << 0;
static final int BOOTSTRAP_VALUE_EXECUTE = 1 << 1;
static final int BOOTSTRAP_VARARGS = 1 << 2;
/*
* Package used when the adapter can't be defined in the adaptee's package (either because it's
* sealed, or because it's a java.* package.
*/
private static final String ADAPTER_PACKAGE_PREFIX = "com/oracle/truffle/host/adapters/";
/*
* Class name suffix used to append to the adaptee class name, when it can be defined in the
* adaptee's package.
*/
private static final String ADAPTER_CLASS_NAME_SUFFIX = "$$Adapter";
private static final int MAX_GENERATED_TYPE_NAME_LENGTH = 255;
private static final String DELEGATE_FIELD_NAME = "delegate";
private static final String IS_FUNCTION_FIELD_NAME = "isFunction";
private static final String PUBLIC_DELEGATE_FIELD_NAME = HostInteropReflect.ADAPTER_DELEGATE_MEMBER;
// Method name prefix for invoking super-methods
static final String SUPER_PREFIX = "super$";
// This is the superclass for our generated adapter.
private final Class superClass;
// Interfaces implemented by our generated adapter.
private final List> interfaces;
/*
* Class loader used as the parent for the class loader we'll create to load the generated
* class. It will be a class loader that has the visibility of all original types (class to
* extend and interfaces to implement) and of the language classes.
*/
private final ClassLoader commonLoader;
private final HostClassCache hostClassCache;
// Is this a generator for the version of the class that can have overrides on the class level?
private final boolean classOverride;
// Binary name of the superClass
private final String superClassName;
// Binary name of the generated class.
private final String generatedClassName;
private final Set abstractMethodNames = new HashSet<>();
private final String samName;
private final Set finalMethods = new HashSet<>();
private final Set methodInfos = new HashSet<>();
private final boolean autoConvertibleFromFunction;
private final boolean hasSuperMethods;
private final boolean hasPublicDelegateField;
private final ClassWriter cw;
/**
* Creates a generator for the bytecode for the adapter for the specified superclass and
* interfaces.
*
* @param superClass the superclass the adapter will extend.
* @param interfaces the interfaces the adapter will implement.
* @param commonLoader the class loader that can see all of superClass, interfaces, and
* {@link HostAdapterServices}.
* @param hostClassCache {@link HostClassCache}
* @param classOverride true to generate the bytecode for the adapter that has both class-level
* and instance-level overrides, false to generate the bytecode for the adapter that
* only has instance-level overrides.
*
* throws AdaptationException if the adapter can not be generated for some reason.
*/
HostAdapterBytecodeGenerator(final Class superClass, final List> interfaces, final ClassLoader commonLoader, HostClassCache hostClassCache, final boolean classOverride) {
assert superClass != null && !superClass.isInterface();
assert interfaces != null;
this.superClass = superClass;
this.interfaces = interfaces;
this.commonLoader = commonLoader;
this.hostClassCache = hostClassCache;
this.classOverride = classOverride;
this.superClassName = Type.getInternalName(superClass);
this.generatedClassName = getGeneratedClassName(superClass, interfaces);
cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS) {
@Override
protected String getCommonSuperClass(final String type1, final String type2) {
/*
* We need to override ClassWriter.getCommonSuperClass to use this factory's
* commonLoader as a class loader to find the common superclass of two types when
* needed.
*/
return HostAdapterBytecodeGenerator.this.getCommonSuperClass(type1, type2);
}
};
cw.visit(Opcodes.V1_8, ACC_PUBLIC | ACC_SUPER, generatedClassName, null, superClassName, getInternalTypeNames(interfaces));
generatePrivateField(DELEGATE_FIELD_NAME, POLYGLOT_VALUE_TYPE_DESCRIPTOR);
this.hasPublicDelegateField = !classOverride;
if (hasPublicDelegateField) {
generatePublicDelegateField();
}
gatherMethods(superClass);
gatherMethods(interfaces);
if (abstractMethodNames.size() == 1) {
this.samName = abstractMethodNames.iterator().next();
generatePrivateField(IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);
} else {
this.samName = null;
}
generateClassInit();
this.autoConvertibleFromFunction = generateConstructors();
generateMethods();
this.hasSuperMethods = generateSuperMethods();
cw.visitEnd();
}
private void generatePrivateField(final String name, final String fieldDesc) {
cw.visitField(ACC_PRIVATE | ACC_FINAL | (classOverride ? ACC_STATIC : 0), name, fieldDesc, null, null).visitEnd();
}
private void generatePublicDelegateField() {
FieldVisitor fw = cw.visitField(ACC_PUBLIC | ACC_FINAL, PUBLIC_DELEGATE_FIELD_NAME, POLYGLOT_VALUE_TYPE_DESCRIPTOR, null, null);
fw.visitEnd();
}
private void loadField(final InstructionAdapter mv, final String name, final String desc) {
if (classOverride) {
mv.getstatic(generatedClassName, name, desc);
} else {
mv.visitVarInsn(ALOAD, 0);
mv.getfield(generatedClassName, name, desc);
}
}
HostAdapterClassLoader createAdapterClassLoader() {
return new HostAdapterClassLoader(generatedClassName, cw.toByteArray());
}
boolean isAutoConvertibleFromFunction() {
return autoConvertibleFromFunction;
}
boolean hasSuperMethods() {
return hasSuperMethods;
}
private static String getGeneratedClassName(final Class superType, final List> interfaces) {
/*
* The class we use to primarily name our adapter is either the superclass, or if it is
* Object (meaning we're just implementing interfaces or extending Object), then the first
* implemented interface or Object.
*/
final Class namingType = superType == Object.class ? (interfaces.isEmpty() ? Object.class : interfaces.get(0)) : superType;
String namingTypeName = namingType.getSimpleName();
if (namingTypeName.isEmpty()) {
namingTypeName = "Adapter";
}
final StringBuilder buf = new StringBuilder();
buf.append(ADAPTER_PACKAGE_PREFIX).append(namingTypeName);
final Iterator> it = interfaces.iterator();
if (superType == Object.class && it.hasNext()) {
it.next(); // Skip first interface, it was used to primarily name the adapter
}
// Append interface names to the adapter name
while (it.hasNext()) {
buf.append("$$").append(it.next().getSimpleName());
}
buf.append(ADAPTER_CLASS_NAME_SUFFIX);
return buf.toString().substring(0, Math.min(MAX_GENERATED_TYPE_NAME_LENGTH, buf.length()));
}
/**
* Given a list of class objects, return an array with their binary names. Used to generate the
* array of interface names to implement.
*
* @param classes the classes
* @return an array of names
*/
private static String[] getInternalTypeNames(final List> classes) {
final int interfaceCount = classes.size();
final String[] interfaceNames = new String[interfaceCount];
for (int i = 0; i < interfaceCount; ++i) {
interfaceNames[i] = Type.getInternalName(classes.get(i));
}
return interfaceNames;
}
private void generateClassInit() {
final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_STATIC, CLASS_INIT, Type.getMethodDescriptor(Type.VOID_TYPE), null, null));
if (classOverride) {
mv.visitLdcInsn(getGeneratedClassAsType());
mv.invokevirtual(CLASS_TYPE_NAME, GET_CLASS_LOADER_NAME, GET_CLASS_LOADER_DESCRIPTOR, false);
mv.invokestatic(SERVICES_CLASS_TYPE_NAME, GET_CLASS_OVERRIDES_METHOD_NAME, GET_CLASS_OVERRIDES_METHOD_DESCRIPTOR, false);
// stack: [delegate]
if (samName != null) {
// If the class is a SAM, allow having a ScriptFunction passed as class overrides
mv.dup();
emitIsFunction(mv);
mv.putstatic(generatedClassName, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);
}
mv.putstatic(generatedClassName, DELEGATE_FIELD_NAME, POLYGLOT_VALUE_TYPE_DESCRIPTOR);
}
endInitMethod(mv);
}
private Type getGeneratedClassAsType() {
return Type.getType('L' + generatedClassName + ';');
}
private static void emitIsFunction(final InstructionAdapter mv) {
mv.invokestatic(SERVICES_CLASS_TYPE_NAME, "isFunction", Type.getMethodDescriptor(Type.getType(boolean.class), OBJECT_TYPE), false);
}
private boolean generateConstructors() {
boolean gotCtor = false;
boolean canBeAutoConverted = false;
for (final Constructor ctor : superClass.getDeclaredConstructors()) {
final int modifier = ctor.getModifiers();
if ((modifier & (Modifier.PUBLIC | Modifier.PROTECTED)) != 0 && !isCallerSensitive(ctor)) {
canBeAutoConverted |= generateConstructors(ctor);
gotCtor = true;
}
}
if (!gotCtor) {
throw new IllegalArgumentException("No accessible constructor: " + superClass.getCanonicalName());
}
return canBeAutoConverted;
}
private boolean generateConstructors(final Constructor ctor) {
if (classOverride) {
/*
* Generate a constructor that just delegates to ctor. This is used with class-level
* overrides, when we want to create instances without further per-instance overrides.
*/
generateDelegatingConstructor(ctor);
return false;
}
/*
* Generate a constructor that delegates to ctor, but takes an additional ScriptObject
* parameter at the beginning of its parameter list.
*/
// generateOverridingConstructor(ctor, false);
boolean fromFunction = samName != null;
generateOverridingConstructor(ctor, fromFunction);
if (!fromFunction) {
return false;
}
/*
* If all our abstract methods have a single name, generate an additional constructor, one
* that takes a ScriptFunction as its first parameter and assigns it as the implementation
* for all abstract methods.
*/
// generateOverridingConstructor(ctor, true);
/*
* If the original type only has a single abstract method name, as well as a default ctor,
* then it can be automatically converted from JS function.
*/
return ctor.getParameterCount() == 0;
}
private void generateDelegatingConstructor(final Constructor ctor) {
final Type originalCtorType = Type.getType(ctor);
final Type[] argTypes = originalCtorType.getArgumentTypes();
// All constructors must be public, even if in the superclass they were protected.
final String methodDescriptor = Type.getMethodDescriptor(originalCtorType.getReturnType(), argTypes);
final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC | (ctor.isVarArgs() ? ACC_VARARGS : 0), INIT, methodDescriptor, null, null));
mv.visitCode();
emitSuperConstructorCall(mv, originalCtorType.getDescriptor());
endInitMethod(mv);
}
/**
* Generates a constructor for the instance adapter class. This constructor will take the same
* arguments as the supertype constructor passed as the argument here, and delegate to it.
* However, it will take an additional argument, either an object or a function (based on the
* value of the "fromFunction" parameter), and initialize all the method handle fields of the
* adapter instance with functions from the script object (or the script function itself, if
* that's what's passed).
*
* The generated constructor will be public, regardless of whether the supertype constructor was
* public or protected. The generated constructor will not be variable arity, even if the
* supertype constructor was.
*
* @param ctor the supertype constructor that is serving as the base for the generated
* constructor.
* @param fromFunction true if we're generating a constructor that initializes SAM types from a
* single ScriptFunction passed to it, false if we're generating a constructor that
* initializes an arbitrary type from a ScriptObject passed to it.
*/
private void generateOverridingConstructor(final Constructor ctor, final boolean fromFunction) {
assert !classOverride;
final Type originalCtorType = Type.getType(ctor);
final Type[] originalArgTypes = originalCtorType.getArgumentTypes();
final int argLen = originalArgTypes.length;
final Type[] newArgTypes = new Type[argLen + 1];
// Insert ScriptFunction|Object as the last argument to the constructor
final Type extraArgumentType = POLYGLOT_VALUE_TYPE;
newArgTypes[argLen] = extraArgumentType;
System.arraycopy(originalArgTypes, 0, newArgTypes, 0, argLen);
// All constructors must be public, even if in the superclass they were protected.
// Existing super constructor (this, args...) triggers generating (this,
// scriptObj, args...).
String signature = Type.getMethodDescriptor(originalCtorType.getReturnType(), newArgTypes);
final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC, INIT, signature, null, null));
mv.visitCode();
// First, invoke super constructor with original arguments.
int offset = emitSuperConstructorCall(mv, originalCtorType.getDescriptor());
if (fromFunction) {
final Label notAFunction = new Label();
final Label end = new Label();
mv.visitVarInsn(ALOAD, offset);
emitIsFunction(mv);
mv.ifeq(notAFunction);
// Function branch
// isFunction = true
mv.visitVarInsn(ALOAD, 0);
mv.iconst(1);
mv.putfield(generatedClassName, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);
mv.goTo(end);
mv.visitLabel(notAFunction);
// Object branch
// isFunction = false
mv.visitVarInsn(ALOAD, 0);
mv.iconst(0);
mv.putfield(generatedClassName, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);
mv.visitLabel(end);
}
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ALOAD, offset); // delegate object
mv.putfield(generatedClassName, DELEGATE_FIELD_NAME, POLYGLOT_VALUE_TYPE_DESCRIPTOR);
if (hasPublicDelegateField) {
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ALOAD, offset); // delegate object
mv.putfield(generatedClassName, PUBLIC_DELEGATE_FIELD_NAME, POLYGLOT_VALUE_TYPE_DESCRIPTOR);
}
endInitMethod(mv);
}
private static void endInitMethod(final InstructionAdapter mv) {
mv.visitInsn(RETURN);
endMethod(mv);
}
private static void endMethod(final InstructionAdapter mv) {
mv.visitMaxs(0, 0);
mv.visitEnd();
}
/**
* Encapsulation of the information used to generate methods in the adapter classes. Basically,
* a wrapper around the reflective Method object, a cached MethodType, and the name of the field
* in the adapter class that will hold the method handle serving as the implementation of this
* method in adapter instances.
*
*/
private static final class MethodInfo {
private final Method method;
private final MethodType type;
private MethodInfo(final Method method) {
this.method = method;
this.type = MethodType.methodType(method.getReturnType(), method.getParameterTypes());
}
@Override
public boolean equals(final Object obj) {
return obj instanceof MethodInfo && equals((MethodInfo) obj);
}
private boolean equals(final MethodInfo other) {
// Only method name and type are used for comparison; method handle field name is not.
return getName().equals(other.getName()) && type.equals(other.type);
}
String getName() {
return method.getName();
}
@Override
public int hashCode() {
return getName().hashCode() ^ type.hashCode();
}
@Override
public String toString() {
return method.toString();
}
}
private void generateMethods() {
for (final MethodInfo mi : methodInfos) {
generateMethod(mi);
}
}
/**
* Generates a method in the adapter class that adapts a method from the original class.
*
* If the super class has a single abstract method, the generated methods will inspect
* the @{code isFunction} field, i.e., if a function object was passed to the constructor; if it
* is true, then methods with the same name will execute the provided function object and other
* methods will fall back to the super method. Else, it will invoke a method of the passed
* "overrides" object if it has an invokable member with the method's name, otherwise it will
* fall back to the super method. If the super method it is abstract, it will throw an
* {@link UnsupportedOperationException}.
*
* If the invoked member or function results in a Throwable that is not one of the method's
* declared exceptions, and is not an unchecked throwable, then it is wrapped into a
* {@link RuntimeException} and the runtime exception is thrown.
*
* @param mi the method info describing the method to be generated.
*/
private void generateMethod(final MethodInfo mi) {
final Method method = mi.method;
final Class[] declaredExceptions = method.getExceptionTypes();
final String[] exceptionNames = getExceptionNames(declaredExceptions);
final MethodType type = mi.type;
final String methodDesc = type.toMethodDescriptorString();
final String name = mi.getName();
final Type asmType = Type.getMethodType(methodDesc);
final Type[] asmArgTypes = asmType.getArgumentTypes();
final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(getAccessModifiers(method), name, methodDesc, null, exceptionNames));
mv.visitCode();
final Type asmReturnType = Type.getType(type.returnType());
final int bootstrapFlags = method.isVarArgs() ? BOOTSTRAP_VARARGS : 0;
final Label defaultBehavior = new Label();
final Label hasMethod = new Label();
final List tryBlocks = new ArrayList<>();
loadField(mv, DELEGATE_FIELD_NAME, POLYGLOT_VALUE_TYPE_DESCRIPTOR);
// For the cases like scripted overridden methods invoked from super constructors get
// adapter global/delegate fields as null, since we
// cannot set these fields before invoking super constructor better solution is opt out of
// scripted overridden method if global/delegate fields
// are null and invoke super method instead
mv.ifnull(defaultBehavior);
// stack: []
// If this is a SAM type...
if (samName != null) {
// ...every method will be checking whether we're initialized with a function.
loadField(mv, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);
// stack: [isFunction]
if (name.equals(samName)) {
final Label notFunction = new Label();
mv.ifeq(notFunction);
// stack: []
// If it's a SAM method, it'll load delegate as the "callee".
loadField(mv, DELEGATE_FIELD_NAME, POLYGLOT_VALUE_TYPE_DESCRIPTOR);
// stack: [delegate]
// Load all parameters on the stack for dynamic invocation.
loadParams(mv, asmArgTypes, 1);
final Label tryBlockStart = new Label();
mv.visitLabel(tryBlockStart);
// Invoke the target method handle
mv.visitInvokeDynamicInsn(name, type.insertParameterTypes(0, Value.class).toMethodDescriptorString(), BOOTSTRAP_HANDLE, BOOTSTRAP_VALUE_EXECUTE | bootstrapFlags);
final Label tryBlockEnd = new Label();
mv.visitLabel(tryBlockEnd);
tryBlocks.add(new TryBlock(tryBlockStart, tryBlockEnd));
mv.areturn(asmReturnType);
mv.visitLabel(notFunction);
// stack: []
} else {
// If it's not a SAM method, and the delegate is a function,
// it'll fall back to default behavior
mv.ifne(defaultBehavior);
// stack: []
}
}
loadField(mv, DELEGATE_FIELD_NAME, POLYGLOT_VALUE_TYPE_DESCRIPTOR);
// stack: [delegate]
if (name.equals("toString")) {
Label hasNoToString = new Label();
// Since every JS Object has a toString, we only override
// "String toString()" it if it's explicitly specified on the object.
mv.dup();
mv.visitLdcInsn(name);
// stack: ["toString", delegate, delegate]
mv.invokestatic(SERVICES_CLASS_TYPE_NAME, HAS_OWN_METHOD_NAME, HAS_OWN_METHOD_DESCRIPTOR, false);
// stack: [hasOwnToString, delegate]
mv.ifne(hasNoToString);
mv.pop();
// stack: []
mv.goTo(defaultBehavior);
mv.visitLabel(hasNoToString);
}
mv.dup();
mv.visitLdcInsn(name);
mv.invokestatic(SERVICES_CLASS_TYPE_NAME, HAS_METHOD_NAME, HAS_METHOD_DESCRIPTOR, false);
mv.ifne(hasMethod);
// stack: [delegate]
// else: no override available, clear the stack
mv.pop();
// No override available, fall back to default behavior
mv.visitLabel(defaultBehavior);
if (Modifier.isAbstract(method.getModifiers())) {
// If the super method is abstract, throw an exception
mv.visitLdcInsn(name);
mv.invokestatic(SERVICES_CLASS_TYPE_NAME, UNSUPPORTED_METHOD_NAME, UNSUPPORTED_METHOD_DESCRIPTOR, false);
mv.athrow();
} else {
// If the super method is not abstract, delegate to it.
emitSuperCall(mv, method.getDeclaringClass(), name, methodDesc);
mv.areturn(Type.getMethodType(methodDesc).getReturnType());
}
mv.visitLabel(hasMethod);
// stack: [delegate]
// Load all parameters on the stack for dynamic invocation.
loadParams(mv, asmArgTypes, 1);
final Label tryBlockStart = new Label();
mv.visitLabel(tryBlockStart);
// Invoke the target method handle
mv.visitInvokeDynamicInsn(name, type.insertParameterTypes(0, Value.class).toMethodDescriptorString(), BOOTSTRAP_HANDLE, BOOTSTRAP_VALUE_INVOKE_MEMBER | bootstrapFlags);
final Label tryBlockEnd = new Label();
mv.visitLabel(tryBlockEnd);
tryBlocks.add(new TryBlock(tryBlockStart, tryBlockEnd));
mv.areturn(asmReturnType);
emitTryCatchBlocks(mv, declaredExceptions, tryBlocks);
endMethod(mv);
}
private static final class TryBlock {
final Label start;
final Label end;
TryBlock(Label start, Label end) {
this.start = start;
this.end = end;
}
}
private static void emitTryCatchBlocks(final InstructionAdapter mv, final Class[] declaredExceptions, final List tryBlocks) {
if (isThrowableDeclared(declaredExceptions)) {
// Method declares Throwable, no need for a try-catch
return;
}
// If Throwable is not declared, we need an adapter from Throwable to RuntimeException
final Label rethrowHandler = new Label();
mv.visitLabel(rethrowHandler);
// Rethrow handler for RuntimeException, Error, and all declared exception types
mv.athrow();
// Add "throw new RuntimeException(Throwable)" handler for Throwable
final Label throwableHandler = new Label();
mv.visitLabel(throwableHandler);
wrapThrowable(mv);
mv.athrow();
for (TryBlock tryBlock : tryBlocks) {
mv.visitTryCatchBlock(tryBlock.start, tryBlock.end, rethrowHandler, RUNTIME_EXCEPTION_TYPE_NAME);
mv.visitTryCatchBlock(tryBlock.start, tryBlock.end, rethrowHandler, ERROR_TYPE_NAME);
for (Class exception : declaredExceptions) {
mv.visitTryCatchBlock(tryBlock.start, tryBlock.end, rethrowHandler, Type.getInternalName(exception));
}
mv.visitTryCatchBlock(tryBlock.start, tryBlock.end, throwableHandler, THROWABLE_TYPE_NAME);
}
}
private static void wrapThrowable(InstructionAdapter mv) {
// original Throwable on the top of the stack
mv.invokestatic(SERVICES_CLASS_TYPE_NAME, WRAP_THROWABLE_METHOD_NAME, WRAP_THROWABLE_METHOD_DESCRIPTOR, false);
}
private static boolean isThrowableDeclared(final Class[] exceptions) {
for (final Class exception : exceptions) {
if (exception == Throwable.class) {
return true;
}
}
return false;
}
private boolean generateSuperMethods() {
boolean hasAccessibleNonAbstractSuperMethods = false;
for (final MethodInfo mi : methodInfos) {
if (!Modifier.isAbstract(mi.method.getModifiers()) && hostClassCache.allowsAccess(mi.method)) {
generateSuperMethod(mi);
hasAccessibleNonAbstractSuperMethods = true;
}
}
return hasAccessibleNonAbstractSuperMethods;
}
private void generateSuperMethod(MethodInfo mi) {
final Method method = mi.method;
final String methodDesc = mi.type.toMethodDescriptorString();
final String name = mi.getName();
final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(getAccessModifiers(method), SUPER_PREFIX + name, methodDesc, null, getExceptionNames(method.getExceptionTypes())));
mv.visitCode();
emitSuperCall(mv, method.getDeclaringClass(), name, methodDesc);
mv.areturn(Type.getMethodType(methodDesc).getReturnType());
endMethod(mv);
}
// find the appropriate super type to use for invokespecial on the given interface
private Class findInvokespecialOwnerFor(final Class owner) {
assert Modifier.isInterface(owner.getModifiers()) : owner + " is not an interface";
if (owner.isAssignableFrom(superClass)) {
return superClass;
}
for (final Class iface : interfaces) {
if (owner.isAssignableFrom(iface)) {
return iface;
}
}
throw new AssertionError("Cannot find the class/interface that extends " + owner);
}
private int emitSuperConstructorCall(final InstructionAdapter mv, final String methodDesc) {
return emitSuperCall(mv, null, INIT, methodDesc, true);
}
private int emitSuperCall(final InstructionAdapter mv, final Class owner, final String name, final String methodDesc) {
return emitSuperCall(mv, owner, name, methodDesc, false);
}
private int emitSuperCall(final InstructionAdapter mv, final Class owner, final String name, final String methodDesc, boolean constructor) {
mv.visitVarInsn(ALOAD, 0);
int nextParam = loadParams(mv, Type.getMethodType(methodDesc).getArgumentTypes(), 1);
// default method - non-abstract interface method
if (!constructor && Modifier.isInterface(owner.getModifiers())) {
// we should call default method on the immediate "super" type - not on (possibly)
// the indirectly inherited interface class!
final Class superType = findInvokespecialOwnerFor(owner);
mv.invokespecial(Type.getInternalName(superType), name, methodDesc, Modifier.isInterface(superType.getModifiers()));
} else {
mv.invokespecial(superClassName, name, methodDesc, false);
}
return nextParam;
}
private static int loadParams(final InstructionAdapter mv, final Type[] paramTypes, final int paramOffset) {
int varOffset = paramOffset;
for (final Type t : paramTypes) {
mv.load(varOffset, t);
varOffset += t.getSize();
}
return varOffset;
}
private static String[] getExceptionNames(final Class[] exceptions) {
final String[] exceptionNames = new String[exceptions.length];
for (int i = 0; i < exceptions.length; ++i) {
exceptionNames[i] = Type.getInternalName(exceptions[i]);
}
return exceptionNames;
}
private static int getAccessModifiers(final Method method) {
return ACC_PUBLIC | (method.isVarArgs() ? ACC_VARARGS : 0);
}
/**
* Gathers methods that can be implemented or overridden from the specified type into this
* factory's {@link #methodInfos} set. It will add all non-final, non-static methods that are
* either public or protected from the type if the type itself is public. If the type is a
* class, the method will recursively invoke itself for its superclass and the interfaces it
* implements, and add further methods that were not directly declared on the class.
*
* @param type the type defining the methods.
*/
private void gatherMethods(final Class type) {
if (Modifier.isPublic(type.getModifiers())) {
final Method[] typeMethods = type.isInterface() ? type.getMethods() : type.getDeclaredMethods();
for (final Method typeMethod : typeMethods) {
final String name = typeMethod.getName();
if (name.startsWith(SUPER_PREFIX)) {
continue;
}
final int mod = typeMethod.getModifiers();
if (Modifier.isStatic(mod)) {
continue;
}
if (Modifier.isPublic(mod) || Modifier.isProtected(mod)) {
final MethodInfo mi = new MethodInfo(typeMethod);
if (Modifier.isFinal(mod) || isExcluded(typeMethod) || isCallerSensitive(typeMethod)) {
finalMethods.add(mi);
} else if (!finalMethods.contains(mi) && methodInfos.add(mi)) {
if (Modifier.isAbstract(mod)) {
abstractMethodNames.add(mi.getName());
}
}
}
}
}
/*
* If the type is a class, visit its superclasses and declared interfaces. If it's an
* interface, we're done. Needing to invoke the method recursively for a non-interface Class
* object is the consequence of needing to see all declared protected methods, and
* Class.getDeclaredMethods() doesn't provide those declared in a superclass. For
* interfaces, we used Class.getMethods(), as we're only interested in public ones there,
* and getMethods() does provide those declared in a superinterface.
*/
if (!type.isInterface()) {
final Class superType = type.getSuperclass();
if (superType != null) {
gatherMethods(superType);
}
for (final Class itf : type.getInterfaces()) {
gatherMethods(itf);
}
}
}
private void gatherMethods(final List> classes) {
for (final Class c : classes) {
gatherMethods(c);
}
}
/**
* Returns true for methods that are not final, but we still never allow them to be overridden
* in adapters, as explicitly declaring them automatically is a bad idea. Currently, this means
* {@code Object.finalize()} and {@code Object.clone()}.
*
* @return true if the method is one of those methods that we never override in adapter classes.
*/
private static boolean isExcluded(Method method) {
if (method.getParameterCount() == 0) {
switch (method.getName()) {
case "finalize":
return true;
case "clone":
return true;
}
}
return false;
}
private String getCommonSuperClass(final String type1, final String type2) {
try {
final Class c1 = Class.forName(type1.replace('/', '.'), false, commonLoader);
final Class c2 = Class.forName(type2.replace('/', '.'), false, commonLoader);
if (c1.isAssignableFrom(c2)) {
return type1;
}
if (c2.isAssignableFrom(c1)) {
return type2;
}
if (c1.isInterface() || c2.isInterface()) {
return OBJECT_TYPE_NAME;
}
return assignableSuperClass(c1, c2).getName().replace('.', '/');
} catch (final ClassNotFoundException e) {
throw new RuntimeException(e);
}
}
private static Class assignableSuperClass(final Class c1, final Class c2) {
final Class superClass = c1.getSuperclass();
return superClass.isAssignableFrom(c2) ? superClass : assignableSuperClass(superClass, c2);
}
private static boolean isCallerSensitive(final Executable e) {
return CALLER_SENSITIVE_ANNOTATION_CLASS != null && e.isAnnotationPresent(CALLER_SENSITIVE_ANNOTATION_CLASS);
}
private static final Class CALLER_SENSITIVE_ANNOTATION_CLASS = findCallerSensitiveAnnotationClass();
private static Class findCallerSensitiveAnnotationClass() {
try {
// JDK 8
return Class.forName("sun.reflect.CallerSensitive").asSubclass(Annotation.class);
} catch (ClassNotFoundException e1) {
}
try {
// JDK 9
return Class.forName("jdk.internal.reflect.CallerSensitive").asSubclass(Annotation.class);
} catch (ClassNotFoundException e2) {
}
return null; // not found
}
}