Java InstructionAdapter.iconst方法代码示例

import jdk.internal.org.objectweb.asm.commons.InstructionAdapter; //导入方法依赖的package包/类
/**
 * 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 of
 * either ScriptObject or ScriptFunction type (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). Additionally, it will create another constructor with an additional
 * Object type parameter that can be used for ScriptObjectMirror objects.
 * The constructor will also store the Nashorn global that was current at the constructor
 * invocation time in a field named "global". 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) {
    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|ScriptObject as the last argument to the constructor
    final Type extraArgumentType = fromFunction ? SCRIPT_FUNCTION_TYPE : SCRIPT_OBJECT_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 <init>(this, args...) triggers generating <init>(this, args..., delegate).
    // Any variable arity constructors become fixed-arity with explicit array arguments.
    final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC, INIT,
            Type.getMethodDescriptor(originalCtorType.getReturnType(), newArgTypes), null, null));

    mv.visitCode();
    // First, invoke super constructor with original arguments.
    final int extraArgOffset = emitSuperConstructorCall(mv, originalCtorType.getDescriptor());

    // Assign "this.global = Context.getGlobal()"
    mv.visitVarInsn(ALOAD, 0);
    GET_NON_NULL_GLOBAL.invoke(mv);
    mv.putfield(generatedClassName, GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);

    // Assign "this.delegate = delegate"
    mv.visitVarInsn(ALOAD, 0);
    mv.visitVarInsn(ALOAD, extraArgOffset);
    mv.putfield(generatedClassName, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);

    if (fromFunction) {
        // Assign "isFunction = true"
        mv.visitVarInsn(ALOAD, 0);
        mv.iconst(1);
        mv.putfield(generatedClassName, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);

    mv.visitVarInsn(ALOAD, 0);
        mv.visitVarInsn(ALOAD, extraArgOffset);
        emitInitCallThis(mv);
    }

    endInitMethod(mv);

    if (! fromFunction) {
        newArgTypes[argLen] = OBJECT_TYPE;
        final InstructionAdapter mv2 = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC, INIT,
                Type.getMethodDescriptor(originalCtorType.getReturnType(), newArgTypes), null, null));
        generateOverridingConstructorWithObjectParam(mv2, originalCtorType.getDescriptor());
    }
}
 

import jdk.internal.org.objectweb.asm.commons.InstructionAdapter; //导入方法依赖的package包/类
private void generateOverridingConstructorWithObjectParam(final InstructionAdapter mv, final String ctorDescriptor) {
    mv.visitCode();
    final int extraArgOffset = emitSuperConstructorCall(mv, ctorDescriptor);

    // Check for ScriptObjectMirror
    mv.visitVarInsn(ALOAD, extraArgOffset);
    mv.instanceOf(SCRIPT_OBJECT_MIRROR_TYPE);
    final Label notMirror = new Label();
    mv.ifeq(notMirror);

    mv.visitVarInsn(ALOAD, 0);
    mv.visitVarInsn(ALOAD, extraArgOffset);
    mv.iconst(0);
    UNWRAP_MIRROR.invoke(mv);
    mv.putfield(generatedClassName, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);

    mv.visitVarInsn(ALOAD, 0);
    mv.visitVarInsn(ALOAD, extraArgOffset);
    mv.iconst(1);
    UNWRAP_MIRROR.invoke(mv);
    mv.putfield(generatedClassName, GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);

    final Label done = new Label();

    if (samName != null) {
        mv.visitVarInsn(ALOAD, 0);
        mv.getfield(generatedClassName, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
        mv.instanceOf(SCRIPT_FUNCTION_TYPE);
        mv.ifeq(done);

        // Assign "isFunction = true"
        mv.visitVarInsn(ALOAD, 0);
        mv.iconst(1);
        mv.putfield(generatedClassName, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);

        mv.visitVarInsn(ALOAD, 0);
        mv.dup();
        mv.getfield(generatedClassName, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
        mv.checkcast(SCRIPT_FUNCTION_TYPE);
        emitInitCallThis(mv);
        mv.goTo(done);
    }

    mv.visitLabel(notMirror);

    // Throw error if not a ScriptObject
    mv.visitVarInsn(ALOAD, extraArgOffset);
    NOT_AN_OBJECT.invoke(mv);

    mv.visitLabel(done);
    endInitMethod(mv);
}
 

import jdk.internal.org.objectweb.asm.commons.InstructionAdapter; //导入方法依赖的package包/类
/**
 * 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 of
 * either ScriptObject or ScriptFunction type (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). There is one method handle field in the adapter class for every method
 * that can be implemented or overridden; the name of every field is same as the name of the method, with a number
 * suffix that makes it unique in case of overloaded methods. The generated constructor will invoke
 * {@link #getHandle(ScriptFunction, MethodType, boolean)} or {@link #getHandle(Object, String, MethodType,
 * boolean)} to obtain the method handles; these methods make sure to add the necessary conversions and arity
 * adjustments so that the resulting method handles can be invoked from generated methods using {@code invokeExact}.
 * The constructor that takes a script function will only initialize the methods with the same name as the single
 * abstract method. The constructor will also store the Nashorn global that was current at the constructor
 * invocation time in a field named "global". 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) {
    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|ScriptObject as the last argument to the constructor
    final Type extraArgumentType = fromFunction ? SCRIPT_FUNCTION_TYPE : SCRIPT_OBJECT_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 <init>(this, args...) triggers generating <init>(this, args..., delegate).
    // Any variable arity constructors become fixed-arity with explicit array arguments.
    final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC, INIT,
            Type.getMethodDescriptor(originalCtorType.getReturnType(), newArgTypes), null, null));

    mv.visitCode();
    // First, invoke super constructor with original arguments.
    final int extraArgOffset = emitSuperConstructorCall(mv, originalCtorType.getDescriptor());

    // Assign "this.global = Context.getGlobal()"
    mv.visitVarInsn(ALOAD, 0);
    GET_NON_NULL_GLOBAL.invoke(mv);
    mv.putfield(generatedClassName, GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);

    // Assign "this.delegate = delegate"
    mv.visitVarInsn(ALOAD, 0);
    mv.visitVarInsn(ALOAD, extraArgOffset);
    mv.putfield(generatedClassName, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);

    if (fromFunction) {
        // Assign "isFunction = true"
        mv.visitVarInsn(ALOAD, 0);
        mv.iconst(1);
        mv.putfield(generatedClassName, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);

    mv.visitVarInsn(ALOAD, 0);
        mv.visitVarInsn(ALOAD, extraArgOffset);
        emitInitCallThis(mv);
    }

    endInitMethod(mv);

    if (! fromFunction) {
        newArgTypes[argLen] = OBJECT_TYPE;
        final InstructionAdapter mv2 = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC, INIT,
                Type.getMethodDescriptor(originalCtorType.getReturnType(), newArgTypes), null, null));
        generateOverridingConstructorWithObjectParam(mv2, originalCtorType.getDescriptor());
    }
}