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	/*
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	/*
	* This file is available under and governed by the GNU General Public
	* License version 2 only, as published by the Free Software Foundation.
	* However, the following notice accompanied the original version of this
	* file:
	*
	* ASM: a very small and fast Java bytecode manipulation framework
	* Copyright (c) 2000-2011 INRIA, France Telecom
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* 3. Neither the name of the copyright holders nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
	* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
	* THE POSSIBILITY OF SUCH DAMAGE.
	*/
	package jdk.internal.org.objectweb.asm;

	/**
	* The input and output stack map frames of a basic block.
	*
	* <p>Stack map frames are computed in two steps:
	*
	* <ul>
	* <li>During the visit of each instruction in MethodWriter, the state of the frame at the end of
	* the current basic block is updated by simulating the action of the instruction on the
	* previous state of this so called "output frame".
	* <li>After all instructions have been visited, a fix point algorithm is used in MethodWriter to
	* compute the "input frame" of each basic block (i.e. the stack map frame at the beginning of
	* the basic block). See {@link MethodWriter#computeAllFrames}.
	* </ul>
	*
	* <p>Output stack map frames are computed relatively to the input frame of the basic block, which
	* is not yet known when output frames are computed. It is therefore necessary to be able to
	* represent abstract types such as "the type at position x in the input frame locals" or "the type
	* at position x from the top of the input frame stack" or even "the type at position x in the input
	* frame, with y more (or less) array dimensions". This explains the rather complicated type format
	* used in this class, explained below.
	*
	* <p>The local variables and the operand stack of input and output frames contain values called
	* "abstract types" hereafter. An abstract type is represented with 4 fields named DIM, KIND, FLAGS
	* and VALUE, packed in a single int value for better performance and memory efficiency:
	*
	* <pre>
	* =====================================
	* \|...DIM\|KIND\|.F\|...............VALUE\|
	* =====================================
	* </pre>
	*
	* <ul>
	* <li>the DIM field, stored in the 6 most significant bits, is a signed number of array
	* dimensions (from -32 to 31, included). It can be retrieved with {@link #DIM_MASK} and a
	* right shift of {@link #DIM_SHIFT}.
	* <li>the KIND field, stored in 4 bits, indicates the kind of VALUE used. These 4 bits can be
	* retrieved with {@link #KIND_MASK} and, without any shift, must be equal to {@link
	* #CONSTANT_KIND}, {@link #REFERENCE_KIND}, {@link #UNINITIALIZED_KIND}, {@link #LOCAL_KIND}
	* or {@link #STACK_KIND}.
	* <li>the FLAGS field, stored in 2 bits, contains up to 2 boolean flags. Currently only one flag
	* is defined, namely {@link #TOP_IF_LONG_OR_DOUBLE_FLAG}.
	* <li>the VALUE field, stored in the remaining 20 bits, contains either
	* <ul>
	* <li>one of the constants {@link #ITEM_TOP}, {@link #ITEM_ASM_BOOLEAN}, {@link
	* #ITEM_ASM_BYTE}, {@link #ITEM_ASM_CHAR} or {@link #ITEM_ASM_SHORT}, {@link
	* #ITEM_INTEGER}, {@link #ITEM_FLOAT}, {@link #ITEM_LONG}, {@link #ITEM_DOUBLE}, {@link
	* #ITEM_NULL} or {@link #ITEM_UNINITIALIZED_THIS}, if KIND is equal to {@link
	* #CONSTANT_KIND}.
	* <li>the index of a {@link Symbol#TYPE_TAG} {@link Symbol} in the type table of a {@link
	* SymbolTable}, if KIND is equal to {@link #REFERENCE_KIND}.
	* <li>the index of an {@link Symbol#UNINITIALIZED_TYPE_TAG} {@link Symbol} in the type
	* table of a SymbolTable, if KIND is equal to {@link #UNINITIALIZED_KIND}.
	* <li>the index of a local variable in the input stack frame, if KIND is equal to {@link
	* #LOCAL_KIND}.
	* <li>a position relatively to the top of the stack of the input stack frame, if KIND is
	* equal to {@link #STACK_KIND},
	* </ul>
	* </ul>
	*
	* <p>Output frames can contain abstract types of any kind and with a positive or negative array
	* dimension (and even unassigned types, represented by 0 - which does not correspond to any valid
	* abstract type value). Input frames can only contain CONSTANT_KIND, REFERENCE_KIND or
	* UNINITIALIZED_KIND abstract types of positive or {@literal null} array dimension. In all cases
	* the type table contains only internal type names (array type descriptors are forbidden - array
	* dimensions must be represented through the DIM field).
	*
	* <p>The LONG and DOUBLE types are always represented by using two slots (LONG + TOP or DOUBLE +
	* TOP), for local variables as well as in the operand stack. This is necessary to be able to
	* simulate DUPx_y instructions, whose effect would be dependent on the concrete types represented
	* by the abstract types in the stack (which are not always known).
	*
	* @author Eric Bruneton
	*/
	class Frame {

	// Constants used in the StackMapTable attribute.
	// See https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.4.

	static final int SAME_FRAME = 0;
	static final int SAME_LOCALS_1_STACK_ITEM_FRAME = 64;
	static final int RESERVED = 128;
	static final int SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED = 247;
	static final int CHOP_FRAME = 248;
	static final int SAME_FRAME_EXTENDED = 251;
	static final int APPEND_FRAME = 252;
	static final int FULL_FRAME = 255;

	static final int ITEM_TOP = 0;
	static final int ITEM_INTEGER = 1;
	static final int ITEM_FLOAT = 2;
	static final int ITEM_DOUBLE = 3;
	static final int ITEM_LONG = 4;
	static final int ITEM_NULL = 5;
	static final int ITEM_UNINITIALIZED_THIS = 6;
	static final int ITEM_OBJECT = 7;
	static final int ITEM_UNINITIALIZED = 8;
	// Additional, ASM specific constants used in abstract types below.
	private static final int ITEM_ASM_BOOLEAN = 9;
	private static final int ITEM_ASM_BYTE = 10;
	private static final int ITEM_ASM_CHAR = 11;
	private static final int ITEM_ASM_SHORT = 12;

	// The size and offset in bits of each field of an abstract type.

	private static final int DIM_SIZE = 6;
	private static final int KIND_SIZE = 4;
	private static final int FLAGS_SIZE = 2;
	private static final int VALUE_SIZE = 32 - DIM_SIZE - KIND_SIZE - FLAGS_SIZE;

	private static final int DIM_SHIFT = KIND_SIZE + FLAGS_SIZE + VALUE_SIZE;
	private static final int KIND_SHIFT = FLAGS_SIZE + VALUE_SIZE;
	private static final int FLAGS_SHIFT = VALUE_SIZE;

	// Bitmasks to get each field of an abstract type.

	private static final int DIM_MASK = ((1 << DIM_SIZE) - 1) << DIM_SHIFT;
	private static final int KIND_MASK = ((1 << KIND_SIZE) - 1) << KIND_SHIFT;
	private static final int VALUE_MASK = (1 << VALUE_SIZE) - 1;

	// Constants to manipulate the DIM field of an abstract type.

	/** The constant to be added to an abstract type to get one with one more array dimension. */
	private static final int ARRAY_OF = +1 << DIM_SHIFT;

	/** The constant to be added to an abstract type to get one with one less array dimension. */
	private static final int ELEMENT_OF = -1 << DIM_SHIFT;

	// Possible values for the KIND field of an abstract type.

	private static final int CONSTANT_KIND = 1 << KIND_SHIFT;
	private static final int REFERENCE_KIND = 2 << KIND_SHIFT;
	private static final int UNINITIALIZED_KIND = 3 << KIND_SHIFT;
	private static final int LOCAL_KIND = 4 << KIND_SHIFT;
	private static final int STACK_KIND = 5 << KIND_SHIFT;

	// Possible flags for the FLAGS field of an abstract type.

	/**
	* A flag used for LOCAL_KIND and STACK_KIND abstract types, indicating that if the resolved,
	* concrete type is LONG or DOUBLE, TOP should be used instead (because the value has been
	* partially overridden with an xSTORE instruction).
	*/
	private static final int TOP_IF_LONG_OR_DOUBLE_FLAG = 1 << FLAGS_SHIFT;

	// Useful predefined abstract types (all the possible CONSTANT_KIND types).

	private static final int TOP = CONSTANT_KIND \| ITEM_TOP;
	private static final int BOOLEAN = CONSTANT_KIND \| ITEM_ASM_BOOLEAN;
	private static final int BYTE = CONSTANT_KIND \| ITEM_ASM_BYTE;
	private static final int CHAR = CONSTANT_KIND \| ITEM_ASM_CHAR;
	private static final int SHORT = CONSTANT_KIND \| ITEM_ASM_SHORT;
	private static final int INTEGER = CONSTANT_KIND \| ITEM_INTEGER;
	private static final int FLOAT = CONSTANT_KIND \| ITEM_FLOAT;
	private static final int LONG = CONSTANT_KIND \| ITEM_LONG;
	private static final int DOUBLE = CONSTANT_KIND \| ITEM_DOUBLE;
	private static final int NULL = CONSTANT_KIND \| ITEM_NULL;
	private static final int UNINITIALIZED_THIS = CONSTANT_KIND \| ITEM_UNINITIALIZED_THIS;

	// -----------------------------------------------------------------------------------------------
	// Instance fields
	// -----------------------------------------------------------------------------------------------

	/** The basic block to which these input and output stack map frames correspond. */
	Label owner;

	/** The input stack map frame locals. This is an array of abstract types. */
	private int[] inputLocals;

	/** The input stack map frame stack. This is an array of abstract types. */
	private int[] inputStack;

	/** The output stack map frame locals. This is an array of abstract types. */
	private int[] outputLocals;

	/** The output stack map frame stack. This is an array of abstract types. */
	private int[] outputStack;

	/**
	* The start of the output stack, relatively to the input stack. This offset is always negative or
	* null. A null offset means that the output stack must be appended to the input stack. A -n
	* offset means that the first n output stack elements must replace the top n input stack
	* elements, and that the other elements must be appended to the input stack.
	*/
	private short outputStackStart;

	/** The index of the top stack element in {@link #outputStack}. */
	private short outputStackTop;

	/** The number of types that are initialized in the basic block. See {@link #initializations}. */
	private int initializationCount;

	/**
	* The abstract types that are initialized in the basic block. A constructor invocation on an
	* UNINITIALIZED or UNINITIALIZED_THIS abstract type must replace <i>every occurrence</i> of this
	* type in the local variables and in the operand stack. This cannot be done during the first step
	* of the algorithm since, during this step, the local variables and the operand stack types are
	* still abstract. It is therefore necessary to store the abstract types of the constructors which
	* are invoked in the basic block, in order to do this replacement during the second step of the
	* algorithm, where the frames are fully computed. Note that this array can contain abstract types
	* that are relative to the input locals or to the input stack.
	*/
	private int[] initializations;

	// -----------------------------------------------------------------------------------------------
	// Constructor
	// -----------------------------------------------------------------------------------------------

	/**
	* Constructs a new Frame.
	*
	* @param owner the basic block to which these input and output stack map frames correspond.
	*/
	Frame(final Label owner) {
	this.owner = owner;
	}

	/**
	* Sets this frame to the value of the given frame.
	*
	* <p>WARNING: after this method is called the two frames share the same data structures. It is
	* recommended to discard the given frame to avoid unexpected side effects.
	*
	* @param frame The new frame value.
	*/
	final void copyFrom(final Frame frame) {
	inputLocals = frame.inputLocals;
	inputStack = frame.inputStack;
	outputStackStart = 0;
	outputLocals = frame.outputLocals;
	outputStack = frame.outputStack;
	outputStackTop = frame.outputStackTop;
	initializationCount = frame.initializationCount;
	initializations = frame.initializations;
	}

	// -----------------------------------------------------------------------------------------------
	// Static methods to get abstract types from other type formats
	// -----------------------------------------------------------------------------------------------

	/**
	* Returns the abstract type corresponding to the given public API frame element type.
	*
	* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
	* @param type a frame element type described using the same format as in {@link
	* MethodVisitor#visitFrame}, i.e. either {@link Opcodes#TOP}, {@link Opcodes#INTEGER}, {@link
	* Opcodes#FLOAT}, {@link Opcodes#LONG}, {@link Opcodes#DOUBLE}, {@link Opcodes#NULL}, or
	* {@link Opcodes#UNINITIALIZED_THIS}, or the internal name of a class, or a Label designating
	* a NEW instruction (for uninitialized types).
	* @return the abstract type corresponding to the given frame element type.
	*/
	static int getAbstractTypeFromApiFormat(final SymbolTable symbolTable, final Object type) {
	if (type instanceof Integer) {
	return CONSTANT_KIND \| ((Integer) type).intValue();
	} else if (type instanceof String) {
	String descriptor = Type.getObjectType((String) type).getDescriptor();
	return getAbstractTypeFromDescriptor(symbolTable, descriptor, 0);
	} else {
	return UNINITIALIZED_KIND
	\| symbolTable.addUninitializedType("", ((Label) type).bytecodeOffset);
	}
	}

	/**
	* Returns the abstract type corresponding to the internal name of a class.
	*
	* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
	* @param internalName the internal name of a class. This must <i>not</i> be an array type
	* descriptor.
	* @return the abstract type value corresponding to the given internal name.
	*/
	static int getAbstractTypeFromInternalName(
	final SymbolTable symbolTable, final String internalName) {
	return REFERENCE_KIND \| symbolTable.addType(internalName);
	}

	/**
	* Returns the abstract type corresponding to the given type descriptor.
	*
	* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
	* @param buffer a string ending with a type descriptor.
	* @param offset the start offset of the type descriptor in buffer.
	* @return the abstract type corresponding to the given type descriptor.
	*/
	private static int getAbstractTypeFromDescriptor(
	final SymbolTable symbolTable, final String buffer, final int offset) {
	String internalName;
	switch (buffer.charAt(offset)) {
	case 'V':
	return 0;
	case 'Z':
	case 'C':
	case 'B':
	case 'S':
	case 'I':
	return INTEGER;
	case 'F':
	return FLOAT;
	case 'J':
	return LONG;
	case 'D':
	return DOUBLE;
	case 'L':
	internalName = buffer.substring(offset + 1, buffer.length() - 1);
	return REFERENCE_KIND \| symbolTable.addType(internalName);
	case '[':
	int elementDescriptorOffset = offset + 1;
	while (buffer.charAt(elementDescriptorOffset) == '[') {
	++elementDescriptorOffset;
	}
	int typeValue;
	switch (buffer.charAt(elementDescriptorOffset)) {
	case 'Z':
	typeValue = BOOLEAN;
	break;
	case 'C':
	typeValue = CHAR;
	break;
	case 'B':
	typeValue = BYTE;
	break;
	case 'S':
	typeValue = SHORT;
	break;
	case 'I':
	typeValue = INTEGER;
	break;
	case 'F':
	typeValue = FLOAT;
	break;
	case 'J':
	typeValue = LONG;
	break;
	case 'D':
	typeValue = DOUBLE;
	break;
	case 'L':
	internalName = buffer.substring(elementDescriptorOffset + 1, buffer.length() - 1);
	typeValue = REFERENCE_KIND \| symbolTable.addType(internalName);
	break;
	default:
	throw new IllegalArgumentException();
	}
	return ((elementDescriptorOffset - offset) << DIM_SHIFT) \| typeValue;
	default:
	throw new IllegalArgumentException();
	}
	}

	// -----------------------------------------------------------------------------------------------
	// Methods related to the input frame
	// -----------------------------------------------------------------------------------------------

	/**
	* Sets the input frame from the given method description. This method is used to initialize the
	* first frame of a method, which is implicit (i.e. not stored explicitly in the StackMapTable
	* attribute).
	*
	* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
	* @param access the method's access flags.
	* @param descriptor the method descriptor.
	* @param maxLocals the maximum number of local variables of the method.
	*/
	final void setInputFrameFromDescriptor(
	final SymbolTable symbolTable,
	final int access,
	final String descriptor,
	final int maxLocals) {
	inputLocals = new int[maxLocals];
	inputStack = new int[0];
	int inputLocalIndex = 0;
	if ((access & Opcodes.ACC_STATIC) == 0) {
	if ((access & Constants.ACC_CONSTRUCTOR) == 0) {
	inputLocals[inputLocalIndex++] =
	REFERENCE_KIND \| symbolTable.addType(symbolTable.getClassName());
	} else {
	inputLocals[inputLocalIndex++] = UNINITIALIZED_THIS;
	}
	}
	for (Type argumentType : Type.getArgumentTypes(descriptor)) {
	int abstractType =
	getAbstractTypeFromDescriptor(symbolTable, argumentType.getDescriptor(), 0);
	inputLocals[inputLocalIndex++] = abstractType;
	if (abstractType == LONG \|\| abstractType == DOUBLE) {
	inputLocals[inputLocalIndex++] = TOP;
	}
	}
	while (inputLocalIndex < maxLocals) {
	inputLocals[inputLocalIndex++] = TOP;
	}
	}

	/**
	* Sets the input frame from the given public API frame description.
	*
	* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
	* @param numLocal the number of local variables.
	* @param local the local variable types, described using the same format as in {@link
	* MethodVisitor#visitFrame}.
	* @param numStack the number of operand stack elements.
	* @param stack the operand stack types, described using the same format as in {@link
	* MethodVisitor#visitFrame}.
	*/
	final void setInputFrameFromApiFormat(
	final SymbolTable symbolTable,
	final int numLocal,
	final Object[] local,
	final int numStack,
	final Object[] stack) {
	int inputLocalIndex = 0;
	for (int i = 0; i < numLocal; ++i) {
	inputLocals[inputLocalIndex++] = getAbstractTypeFromApiFormat(symbolTable, local[i]);
	if (local[i] == Opcodes.LONG \|\| local[i] == Opcodes.DOUBLE) {
	inputLocals[inputLocalIndex++] = TOP;
	}
	}
	while (inputLocalIndex < inputLocals.length) {
	inputLocals[inputLocalIndex++] = TOP;
	}
	int numStackTop = 0;
	for (int i = 0; i < numStack; ++i) {
	if (stack[i] == Opcodes.LONG \|\| stack[i] == Opcodes.DOUBLE) {
	++numStackTop;
	}
	}
	inputStack = new int[numStack + numStackTop];
	int inputStackIndex = 0;
	for (int i = 0; i < numStack; ++i) {
	inputStack[inputStackIndex++] = getAbstractTypeFromApiFormat(symbolTable, stack[i]);
	if (stack[i] == Opcodes.LONG \|\| stack[i] == Opcodes.DOUBLE) {
	inputStack[inputStackIndex++] = TOP;
	}
	}
	outputStackTop = 0;
	initializationCount = 0;
	}

	final int getInputStackSize() {
	return inputStack.length;
	}

	// -----------------------------------------------------------------------------------------------
	// Methods related to the output frame
	// -----------------------------------------------------------------------------------------------

	/**
	* Returns the abstract type stored at the given local variable index in the output frame.
	*
	* @param localIndex the index of the local variable whose value must be returned.
	* @return the abstract type stored at the given local variable index in the output frame.
	*/
	private int getLocal(final int localIndex) {
	if (outputLocals == null \|\| localIndex >= outputLocals.length) {
	// If this local has never been assigned in this basic block, it is still equal to its value
	// in the input frame.
	return LOCAL_KIND \| localIndex;
	} else {
	int abstractType = outputLocals[localIndex];
	if (abstractType == 0) {
	// If this local has never been assigned in this basic block, so it is still equal to its
	// value in the input frame.
	abstractType = outputLocals[localIndex] = LOCAL_KIND \| localIndex;
	}
	return abstractType;
	}
	}

	/**
	* Replaces the abstract type stored at the given local variable index in the output frame.
	*
	* @param localIndex the index of the output frame local variable that must be set.
	* @param abstractType the value that must be set.
	*/
	private void setLocal(final int localIndex, final int abstractType) {
	// Create and/or resize the output local variables array if necessary.
	if (outputLocals == null) {
	outputLocals = new int[10];
	}
	int outputLocalsLength = outputLocals.length;
	if (localIndex >= outputLocalsLength) {
	int[] newOutputLocals = new int[Math.max(localIndex + 1, 2 * outputLocalsLength)];
	System.arraycopy(outputLocals, 0, newOutputLocals, 0, outputLocalsLength);
	outputLocals = newOutputLocals;
	}
	// Set the local variable.
	outputLocals[localIndex] = abstractType;
	}

	/**
	* Pushes the given abstract type on the output frame stack.
	*
	* @param abstractType an abstract type.
	*/
	private void push(final int abstractType) {
	// Create and/or resize the output stack array if necessary.
	if (outputStack == null) {
	outputStack = new int[10];
	}
	int outputStackLength = outputStack.length;
	if (outputStackTop >= outputStackLength) {
	int[] newOutputStack = new int[Math.max(outputStackTop + 1, 2 * outputStackLength)];
	System.arraycopy(outputStack, 0, newOutputStack, 0, outputStackLength);
	outputStack = newOutputStack;
	}
	// Pushes the abstract type on the output stack.
	outputStack[outputStackTop++] = abstractType;
	// Updates the maximum size reached by the output stack, if needed (note that this size is
	// relative to the input stack size, which is not known yet).
	short outputStackSize = (short) (outputStackStart + outputStackTop);
	if (outputStackSize > owner.outputStackMax) {
	owner.outputStackMax = outputStackSize;
	}
	}

	/**
	* Pushes the abstract type corresponding to the given descriptor on the output frame stack.
	*
	* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
	* @param descriptor a type or method descriptor (in which case its return type is pushed).
	*/
	private void push(final SymbolTable symbolTable, final String descriptor) {
	int typeDescriptorOffset =
	descriptor.charAt(0) == '(' ? Type.getReturnTypeOffset(descriptor) : 0;
	int abstractType = getAbstractTypeFromDescriptor(symbolTable, descriptor, typeDescriptorOffset);
	if (abstractType != 0) {
	push(abstractType);
	if (abstractType == LONG \|\| abstractType == DOUBLE) {
	push(TOP);
	}
	}
	}

	/**
	* Pops an abstract type from the output frame stack and returns its value.
	*
	* @return the abstract type that has been popped from the output frame stack.
	*/
	private int pop() {
	if (outputStackTop > 0) {
	return outputStack[--outputStackTop];
	} else {
	// If the output frame stack is empty, pop from the input stack.
	return STACK_KIND \| -(--outputStackStart);
	}
	}

	/**
	* Pops the given number of abstract types from the output frame stack.
	*
	* @param elements the number of abstract types that must be popped.
	*/
	private void pop(final int elements) {
	if (outputStackTop >= elements) {
	outputStackTop -= elements;
	} else {
	// If the number of elements to be popped is greater than the number of elements in the output
	// stack, clear it, and pop the remaining elements from the input stack.
	outputStackStart -= elements - outputStackTop;
	outputStackTop = 0;
	}
	}

	/**
	* Pops as many abstract types from the output frame stack as described by the given descriptor.
	*
	* @param descriptor a type or method descriptor (in which case its argument types are popped).
	*/
	private void pop(final String descriptor) {
	char firstDescriptorChar = descriptor.charAt(0);
	if (firstDescriptorChar == '(') {
	pop((Type.getArgumentsAndReturnSizes(descriptor) >> 2) - 1);
	} else if (firstDescriptorChar == 'J' \|\| firstDescriptorChar == 'D') {
	pop(2);
	} else {
	pop(1);
	}
	}

	// -----------------------------------------------------------------------------------------------
	// Methods to handle uninitialized types
	// -----------------------------------------------------------------------------------------------

	/**
	* Adds an abstract type to the list of types on which a constructor is invoked in the basic
	* block.
	*
	* @param abstractType an abstract type on a which a constructor is invoked.
	*/
	private void addInitializedType(final int abstractType) {
	// Create and/or resize the initializations array if necessary.
	if (initializations == null) {
	initializations = new int[2];
	}
	int initializationsLength = initializations.length;
	if (initializationCount >= initializationsLength) {
	int[] newInitializations =
	new int[Math.max(initializationCount + 1, 2 * initializationsLength)];
	System.arraycopy(initializations, 0, newInitializations, 0, initializationsLength);
	initializations = newInitializations;
	}
	// Store the abstract type.
	initializations[initializationCount++] = abstractType;
	}

	/**
	* Returns the "initialized" abstract type corresponding to the given abstract type.
	*
	* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
	* @param abstractType an abstract type.
	* @return the REFERENCE_KIND abstract type corresponding to abstractType if it is
	* UNINITIALIZED_THIS or an UNINITIALIZED_KIND abstract type for one of the types on which a
	* constructor is invoked in the basic block. Otherwise returns abstractType.
	*/
	private int getInitializedType(final SymbolTable symbolTable, final int abstractType) {
	if (abstractType == UNINITIALIZED_THIS
	\|\| (abstractType & (DIM_MASK \| KIND_MASK)) == UNINITIALIZED_KIND) {
	for (int i = 0; i < initializationCount; ++i) {
	int initializedType = initializations[i];
	int dim = initializedType & DIM_MASK;
	int kind = initializedType & KIND_MASK;
	int value = initializedType & VALUE_MASK;
	if (kind == LOCAL_KIND) {
	initializedType = dim + inputLocals[value];
	} else if (kind == STACK_KIND) {
	initializedType = dim + inputStack[inputStack.length - value];
	}
	if (abstractType == initializedType) {
	if (abstractType == UNINITIALIZED_THIS) {
	return REFERENCE_KIND \| symbolTable.addType(symbolTable.getClassName());
	} else {
	return REFERENCE_KIND
	\| symbolTable.addType(symbolTable.getType(abstractType & VALUE_MASK).value);
	}
	}
	}
	}
	return abstractType;
	}

	// -----------------------------------------------------------------------------------------------
	// Main method, to simulate the execution of each instruction on the output frame
	// -----------------------------------------------------------------------------------------------

	/**
	* Simulates the action of the given instruction on the output stack frame.
	*
	* @param opcode the opcode of the instruction.
	* @param arg the numeric operand of the instruction, if any.
	* @param argSymbol the Symbol operand of the instruction, if any.
	* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
	*/
	void execute(
	final int opcode, final int arg, final Symbol argSymbol, final SymbolTable symbolTable) {
	// Abstract types popped from the stack or read from local variables.
	int abstractType1;
	int abstractType2;
	int abstractType3;
	int abstractType4;
	switch (opcode) {
	case Opcodes.NOP:
	case Opcodes.INEG:
	case Opcodes.LNEG:
	case Opcodes.FNEG:
	case Opcodes.DNEG:
	case Opcodes.I2B:
	case Opcodes.I2C:
	case Opcodes.I2S:
	case Opcodes.GOTO:
	case Opcodes.RETURN:
	break;
	case Opcodes.ACONST_NULL:
	push(NULL);
	break;
	case Opcodes.ICONST_M1:
	case Opcodes.ICONST_0:
	case Opcodes.ICONST_1:
	case Opcodes.ICONST_2:
	case Opcodes.ICONST_3:
	case Opcodes.ICONST_4:
	case Opcodes.ICONST_5:
	case Opcodes.BIPUSH:
	case Opcodes.SIPUSH:
	case Opcodes.ILOAD:
	push(INTEGER);
	break;
	case Opcodes.LCONST_0:
	case Opcodes.LCONST_1:
	case Opcodes.LLOAD:
	push(LONG);
	push(TOP);
	break;
	case Opcodes.FCONST_0:
	case Opcodes.FCONST_1:
	case Opcodes.FCONST_2:
	case Opcodes.FLOAD:
	push(FLOAT);
	break;
	case Opcodes.DCONST_0:
	case Opcodes.DCONST_1:
	case Opcodes.DLOAD:
	push(DOUBLE);
	push(TOP);
	break;
	case Opcodes.LDC:
	switch (argSymbol.tag) {
	case Symbol.CONSTANT_INTEGER_TAG:
	push(INTEGER);
	break;
	case Symbol.CONSTANT_LONG_TAG:
	push(LONG);
	push(TOP);
	break;
	case Symbol.CONSTANT_FLOAT_TAG:
	push(FLOAT);
	break;
	case Symbol.CONSTANT_DOUBLE_TAG:
	push(DOUBLE);
	push(TOP);
	break;
	case Symbol.CONSTANT_CLASS_TAG:
	push(REFERENCE_KIND \| symbolTable.addType("java/lang/Class"));
	break;
	case Symbol.CONSTANT_STRING_TAG:
	push(REFERENCE_KIND \| symbolTable.addType("java/lang/String"));
	break;
	case Symbol.CONSTANT_METHOD_TYPE_TAG:
	push(REFERENCE_KIND \| symbolTable.addType("java/lang/invoke/MethodType"));
	break;
	case Symbol.CONSTANT_METHOD_HANDLE_TAG:
	push(REFERENCE_KIND \| symbolTable.addType("java/lang/invoke/MethodHandle"));
	break;
	case Symbol.CONSTANT_DYNAMIC_TAG:
	push(symbolTable, argSymbol.value);
	break;
	default:
	throw new AssertionError();
	}
	break;
	case Opcodes.ALOAD:
	push(getLocal(arg));
	break;
	case Opcodes.LALOAD:
	case Opcodes.D2L:
	pop(2);
	push(LONG);
	push(TOP);
	break;
	case Opcodes.DALOAD:
	case Opcodes.L2D:
	pop(2);
	push(DOUBLE);
	push(TOP);
	break;
	case Opcodes.AALOAD:
	pop(1);
	abstractType1 = pop();
	push(abstractType1 == NULL ? abstractType1 : ELEMENT_OF + abstractType1);
	break;
	case Opcodes.ISTORE:
	case Opcodes.FSTORE:
	case Opcodes.ASTORE:
	abstractType1 = pop();
	setLocal(arg, abstractType1);
	if (arg > 0) {
	int previousLocalType = getLocal(arg - 1);
	if (previousLocalType == LONG \|\| previousLocalType == DOUBLE) {
	setLocal(arg - 1, TOP);
	} else if ((previousLocalType & KIND_MASK) == LOCAL_KIND
	\|\| (previousLocalType & KIND_MASK) == STACK_KIND) {
	// The type of the previous local variable is not known yet, but if it later appears
	// to be LONG or DOUBLE, we should then use TOP instead.
	setLocal(arg - 1, previousLocalType \| TOP_IF_LONG_OR_DOUBLE_FLAG);
	}
	}
	break;
	case Opcodes.LSTORE:
	case Opcodes.DSTORE:
	pop(1);
	abstractType1 = pop();
	setLocal(arg, abstractType1);
	setLocal(arg + 1, TOP);
	if (arg > 0) {
	int previousLocalType = getLocal(arg - 1);
	if (previousLocalType == LONG \|\| previousLocalType == DOUBLE) {
	setLocal(arg - 1, TOP);
	} else if ((previousLocalType & KIND_MASK) == LOCAL_KIND
	\|\| (previousLocalType & KIND_MASK) == STACK_KIND) {
	// The type of the previous local variable is not known yet, but if it later appears
	// to be LONG or DOUBLE, we should then use TOP instead.
	setLocal(arg - 1, previousLocalType \| TOP_IF_LONG_OR_DOUBLE_FLAG);
	}
	}
	break;
	case Opcodes.IASTORE:
	case Opcodes.BASTORE:
	case Opcodes.CASTORE:
	case Opcodes.SASTORE:
	case Opcodes.FASTORE:
	case Opcodes.AASTORE:
	pop(3);
	break;
	case Opcodes.LASTORE:
	case Opcodes.DASTORE:
	pop(4);
	break;
	case Opcodes.POP:
	case Opcodes.IFEQ:
	case Opcodes.IFNE:
	case Opcodes.IFLT:
	case Opcodes.IFGE:
	case Opcodes.IFGT:
	case Opcodes.IFLE:
	case Opcodes.IRETURN:
	case Opcodes.FRETURN:
	case Opcodes.ARETURN:
	case Opcodes.TABLESWITCH:
	case Opcodes.LOOKUPSWITCH:
	case Opcodes.ATHROW:
	case Opcodes.MONITORENTER:
	case Opcodes.MONITOREXIT:
	case Opcodes.IFNULL:
	case Opcodes.IFNONNULL:
	pop(1);
	break;
	case Opcodes.POP2:
	case Opcodes.IF_ICMPEQ:
	case Opcodes.IF_ICMPNE:
	case Opcodes.IF_ICMPLT:
	case Opcodes.IF_ICMPGE:
	case Opcodes.IF_ICMPGT:
	case Opcodes.IF_ICMPLE:
	case Opcodes.IF_ACMPEQ:
	case Opcodes.IF_ACMPNE:
	case Opcodes.LRETURN:
	case Opcodes.DRETURN:
	pop(2);
	break;
	case Opcodes.DUP:
	abstractType1 = pop();
	push(abstractType1);
	push(abstractType1);
	break;
	case Opcodes.DUP_X1:
	abstractType1 = pop();
	abstractType2 = pop();
	push(abstractType1);
	push(abstractType2);
	push(abstractType1);
	break;
	case Opcodes.DUP_X2:
	abstractType1 = pop();
	abstractType2 = pop();
	abstractType3 = pop();
	push(abstractType1);
	push(abstractType3);
	push(abstractType2);
	push(abstractType1);
	break;
	case Opcodes.DUP2:
	abstractType1 = pop();
	abstractType2 = pop();
	push(abstractType2);
	push(abstractType1);
	push(abstractType2);
	push(abstractType1);
	break;
	case Opcodes.DUP2_X1:
	abstractType1 = pop();
	abstractType2 = pop();
	abstractType3 = pop();
	push(abstractType2);
	push(abstractType1);
	push(abstractType3);
	push(abstractType2);
	push(abstractType1);
	break;
	case Opcodes.DUP2_X2:
	abstractType1 = pop();
	abstractType2 = pop();
	abstractType3 = pop();
	abstractType4 = pop();
	push(abstractType2);
	push(abstractType1);
	push(abstractType4);
	push(abstractType3);
	push(abstractType2);
	push(abstractType1);
	break;
	case Opcodes.SWAP:
	abstractType1 = pop();
	abstractType2 = pop();
	push(abstractType1);
	push(abstractType2);
	break;
	case Opcodes.IALOAD:
	case Opcodes.BALOAD:
	case Opcodes.CALOAD:
	case Opcodes.SALOAD:
	case Opcodes.IADD:
	case Opcodes.ISUB:
	case Opcodes.IMUL:
	case Opcodes.IDIV:
	case Opcodes.IREM:
	case Opcodes.IAND:
	case Opcodes.IOR:
	case Opcodes.IXOR:
	case Opcodes.ISHL:
	case Opcodes.ISHR:
	case Opcodes.IUSHR:
	case Opcodes.L2I:
	case Opcodes.D2I:
	case Opcodes.FCMPL:
	case Opcodes.FCMPG:
	pop(2);
	push(INTEGER);
	break;
	case Opcodes.LADD:
	case Opcodes.LSUB:
	case Opcodes.LMUL:
	case Opcodes.LDIV:
	case Opcodes.LREM:
	case Opcodes.LAND:
	case Opcodes.LOR:
	case Opcodes.LXOR:
	pop(4);
	push(LONG);
	push(TOP);
	break;
	case Opcodes.FALOAD:
	case Opcodes.FADD:
	case Opcodes.FSUB:
	case Opcodes.FMUL:
	case Opcodes.FDIV:
	case Opcodes.FREM:
	case Opcodes.L2F:
	case Opcodes.D2F:
	pop(2);
	push(FLOAT);
	break;
	case Opcodes.DADD:
	case Opcodes.DSUB:
	case Opcodes.DMUL:
	case Opcodes.DDIV:
	case Opcodes.DREM:
	pop(4);
	push(DOUBLE);
	push(TOP);
	break;
	case Opcodes.LSHL:
	case Opcodes.LSHR:
	case Opcodes.LUSHR:
	pop(3);
	push(LONG);
	push(TOP);
	break;
	case Opcodes.IINC:
	setLocal(arg, INTEGER);
	break;
	case Opcodes.I2L:
	case Opcodes.F2L:
	pop(1);
	push(LONG);
	push(TOP);
	break;
	case Opcodes.I2F:
	pop(1);
	push(FLOAT);
	break;
	case Opcodes.I2D:
	case Opcodes.F2D:
	pop(1);
	push(DOUBLE);
	push(TOP);
	break;
	case Opcodes.F2I:
	case Opcodes.ARRAYLENGTH:
	case Opcodes.INSTANCEOF:
	pop(1);
	push(INTEGER);
	break;
	case Opcodes.LCMP:
	case Opcodes.DCMPL:
	case Opcodes.DCMPG:
	pop(4);
	push(INTEGER);
	break;
	case Opcodes.JSR:
	case Opcodes.RET:
	throw new IllegalArgumentException("JSR/RET are not supported with computeFrames option");
	case Opcodes.GETSTATIC:
	push(symbolTable, argSymbol.value);
	break;
	case Opcodes.PUTSTATIC:
	pop(argSymbol.value);
	break;
	case Opcodes.GETFIELD:
	pop(1);
	push(symbolTable, argSymbol.value);
	break;
	case Opcodes.PUTFIELD:
	pop(argSymbol.value);
	pop();
	break;
	case Opcodes.INVOKEVIRTUAL:
	case Opcodes.INVOKESPECIAL:
	case Opcodes.INVOKESTATIC:
	case Opcodes.INVOKEINTERFACE:
	pop(argSymbol.value);
	if (opcode != Opcodes.INVOKESTATIC) {
	abstractType1 = pop();
	if (opcode == Opcodes.INVOKESPECIAL && argSymbol.name.charAt(0) == '<') {
	addInitializedType(abstractType1);
	}
	}
	push(symbolTable, argSymbol.value);
	break;
	case Opcodes.INVOKEDYNAMIC:
	pop(argSymbol.value);
	push(symbolTable, argSymbol.value);
	break;
	case Opcodes.NEW:
	push(UNINITIALIZED_KIND \| symbolTable.addUninitializedType(argSymbol.value, arg));
	break;
	case Opcodes.NEWARRAY:
	pop();
	switch (arg) {
	case Opcodes.T_BOOLEAN:
	push(ARRAY_OF \| BOOLEAN);
	break;
	case Opcodes.T_CHAR:
	push(ARRAY_OF \| CHAR);
	break;
	case Opcodes.T_BYTE:
	push(ARRAY_OF \| BYTE);
	break;
	case Opcodes.T_SHORT:
	push(ARRAY_OF \| SHORT);
	break;
	case Opcodes.T_INT:
	push(ARRAY_OF \| INTEGER);
	break;
	case Opcodes.T_FLOAT:
	push(ARRAY_OF \| FLOAT);
	break;
	case Opcodes.T_DOUBLE:
	push(ARRAY_OF \| DOUBLE);
	break;
	case Opcodes.T_LONG:
	push(ARRAY_OF \| LONG);
	break;
	default:
	throw new IllegalArgumentException();
	}
	break;
	case Opcodes.ANEWARRAY:
	String arrayElementType = argSymbol.value;
	pop();
	if (arrayElementType.charAt(0) == '[') {
	push(symbolTable, '[' + arrayElementType);
	} else {
	push(ARRAY_OF \| REFERENCE_KIND \| symbolTable.addType(arrayElementType));
	}
	break;
	case Opcodes.CHECKCAST:
	String castType = argSymbol.value;
	pop();
	if (castType.charAt(0) == '[') {
	push(symbolTable, castType);
	} else {
	push(REFERENCE_KIND \| symbolTable.addType(castType));
	}
	break;
	case Opcodes.MULTIANEWARRAY:
	pop(arg);
	push(symbolTable, argSymbol.value);
	break;
	default:
	throw new IllegalArgumentException();
	}
	}

	// -----------------------------------------------------------------------------------------------
	// Frame merging methods, used in the second step of the stack map frame computation algorithm
	// -----------------------------------------------------------------------------------------------

	/**
	* Computes the concrete output type corresponding to a given abstract output type.
	*
	* @param abstractOutputType an abstract output type.
	* @param numStack the size of the input stack, used to resolve abstract output types of
	* STACK_KIND kind.
	* @return the concrete output type corresponding to 'abstractOutputType'.
	*/
	private int getConcreteOutputType(final int abstractOutputType, final int numStack) {
	int dim = abstractOutputType & DIM_MASK;
	int kind = abstractOutputType & KIND_MASK;
	if (kind == LOCAL_KIND) {
	// By definition, a LOCAL_KIND type designates the concrete type of a local variable at
	// the beginning of the basic block corresponding to this frame (which is known when
	// this method is called, but was not when the abstract type was computed).
	int concreteOutputType = dim + inputLocals[abstractOutputType & VALUE_MASK];
	if ((abstractOutputType & TOP_IF_LONG_OR_DOUBLE_FLAG) != 0
	&& (concreteOutputType == LONG \|\| concreteOutputType == DOUBLE)) {
	concreteOutputType = TOP;
	}
	return concreteOutputType;
	} else if (kind == STACK_KIND) {
	// By definition, a STACK_KIND type designates the concrete type of a local variable at
	// the beginning of the basic block corresponding to this frame (which is known when
	// this method is called, but was not when the abstract type was computed).
	int concreteOutputType = dim + inputStack[numStack - (abstractOutputType & VALUE_MASK)];
	if ((abstractOutputType & TOP_IF_LONG_OR_DOUBLE_FLAG) != 0
	&& (concreteOutputType == LONG \|\| concreteOutputType == DOUBLE)) {
	concreteOutputType = TOP;
	}
	return concreteOutputType;
	} else {
	return abstractOutputType;
	}
	}

	/**
	* Merges the input frame of the given {@link Frame} with the input and output frames of this
	* {@link Frame}. Returns {@literal true} if the given frame has been changed by this operation
	* (the input and output frames of this {@link Frame} are never changed).
	*
	* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
	* @param dstFrame the {@link Frame} whose input frame must be updated. This should be the frame
	* of a successor, in the control flow graph, of the basic block corresponding to this frame.
	* @param catchTypeIndex if 'frame' corresponds to an exception handler basic block, the type
	* table index of the caught exception type, otherwise 0.
	* @return {@literal true} if the input frame of 'frame' has been changed by this operation.
	*/
	final boolean merge(
	final SymbolTable symbolTable, final Frame dstFrame, final int catchTypeIndex) {
	boolean frameChanged = false;

	// Compute the concrete types of the local variables at the end of the basic block corresponding
	// to this frame, by resolving its abstract output types, and merge these concrete types with
	// those of the local variables in the input frame of dstFrame.
	int numLocal = inputLocals.length;
	int numStack = inputStack.length;
	if (dstFrame.inputLocals == null) {
	dstFrame.inputLocals = new int[numLocal];
	frameChanged = true;
	}
	for (int i = 0; i < numLocal; ++i) {
	int concreteOutputType;
	if (outputLocals != null && i < outputLocals.length) {
	int abstractOutputType = outputLocals[i];
	if (abstractOutputType == 0) {
	// If the local variable has never been assigned in this basic block, it is equal to its
	// value at the beginning of the block.
	concreteOutputType = inputLocals[i];
	} else {
	concreteOutputType = getConcreteOutputType(abstractOutputType, numStack);
	}
	} else {
	// If the local variable has never been assigned in this basic block, it is equal to its
	// value at the beginning of the block.
	concreteOutputType = inputLocals[i];
	}
	// concreteOutputType might be an uninitialized type from the input locals or from the input
	// stack. However, if a constructor has been called for this class type in the basic block,
	// then this type is no longer uninitialized at the end of basic block.
	if (initializations != null) {
	concreteOutputType = getInitializedType(symbolTable, concreteOutputType);
	}
	frameChanged \|= merge(symbolTable, concreteOutputType, dstFrame.inputLocals, i);
	}

	// If dstFrame is an exception handler block, it can be reached from any instruction of the
	// basic block corresponding to this frame, in particular from the first one. Therefore, the
	// input locals of dstFrame should be compatible (i.e. merged) with the input locals of this
	// frame (and the input stack of dstFrame should be compatible, i.e. merged, with a one
	// element stack containing the caught exception type).
	if (catchTypeIndex > 0) {
	for (int i = 0; i < numLocal; ++i) {
	frameChanged \|= merge(symbolTable, inputLocals[i], dstFrame.inputLocals, i);
	}
	if (dstFrame.inputStack == null) {
	dstFrame.inputStack = new int[1];
	frameChanged = true;
	}
	frameChanged \|= merge(symbolTable, catchTypeIndex, dstFrame.inputStack, 0);
	return frameChanged;
	}

	// Compute the concrete types of the stack operands at the end of the basic block corresponding
	// to this frame, by resolving its abstract output types, and merge these concrete types with
	// those of the stack operands in the input frame of dstFrame.
	int numInputStack = inputStack.length + outputStackStart;
	if (dstFrame.inputStack == null) {
	dstFrame.inputStack = new int[numInputStack + outputStackTop];
	frameChanged = true;
	}
	// First, do this for the stack operands that have not been popped in the basic block
	// corresponding to this frame, and which are therefore equal to their value in the input
	// frame (except for uninitialized types, which may have been initialized).
	for (int i = 0; i < numInputStack; ++i) {
	int concreteOutputType = inputStack[i];
	if (initializations != null) {
	concreteOutputType = getInitializedType(symbolTable, concreteOutputType);
	}
	frameChanged \|= merge(symbolTable, concreteOutputType, dstFrame.inputStack, i);
	}
	// Then, do this for the stack operands that have pushed in the basic block (this code is the
	// same as the one above for local variables).
	for (int i = 0; i < outputStackTop; ++i) {
	int abstractOutputType = outputStack[i];
	int concreteOutputType = getConcreteOutputType(abstractOutputType, numStack);
	if (initializations != null) {
	concreteOutputType = getInitializedType(symbolTable, concreteOutputType);
	}
	frameChanged \|=
	merge(symbolTable, concreteOutputType, dstFrame.inputStack, numInputStack + i);
	}
	return frameChanged;
	}

	/**
	* Merges the type at the given index in the given abstract type array with the given type.
	* Returns {@literal true} if the type array has been modified by this operation.
	*
	* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
	* @param sourceType the abstract type with which the abstract type array element must be merged.
	* This type should be of {@link #CONSTANT_KIND}, {@link #REFERENCE_KIND} or {@link
	* #UNINITIALIZED_KIND} kind, with positive or {@literal null} array dimensions.
	* @param dstTypes an array of abstract types. These types should be of {@link #CONSTANT_KIND},
	* {@link #REFERENCE_KIND} or {@link #UNINITIALIZED_KIND} kind, with positive or {@literal
	* null} array dimensions.
	* @param dstIndex the index of the type that must be merged in dstTypes.
	* @return {@literal true} if the type array has been modified by this operation.
	*/
	private static boolean merge(
	final SymbolTable symbolTable,
	final int sourceType,
	final int[] dstTypes,
	final int dstIndex) {
	int dstType = dstTypes[dstIndex];
	if (dstType == sourceType) {
	// If the types are equal, merge(sourceType, dstType) = dstType, so there is no change.
	return false;
	}
	int srcType = sourceType;
	if ((sourceType & ~DIM_MASK) == NULL) {
	if (dstType == NULL) {
	return false;
	}
	srcType = NULL;
	}
	if (dstType == 0) {
	// If dstTypes[dstIndex] has never been assigned, merge(srcType, dstType) = srcType.
	dstTypes[dstIndex] = srcType;
	return true;
	}
	int mergedType;
	if ((dstType & DIM_MASK) != 0 \|\| (dstType & KIND_MASK) == REFERENCE_KIND) {
	// If dstType is a reference type of any array dimension.
	if (srcType == NULL) {
	// If srcType is the NULL type, merge(srcType, dstType) = dstType, so there is no change.
	return false;
	} else if ((srcType & (DIM_MASK \| KIND_MASK)) == (dstType & (DIM_MASK \| KIND_MASK))) {
	// If srcType has the same array dimension and the same kind as dstType.
	if ((dstType & KIND_MASK) == REFERENCE_KIND) {
	// If srcType and dstType are reference types with the same array dimension,
	// merge(srcType, dstType) = dim(srcType) \| common super class of srcType and dstType.
	mergedType =
	(srcType & DIM_MASK)
	\| REFERENCE_KIND
	\| symbolTable.addMergedType(srcType & VALUE_MASK, dstType & VALUE_MASK);
	} else {
	// If srcType and dstType are array types of equal dimension but different element types,
	// merge(srcType, dstType) = dim(srcType) - 1 \| java/lang/Object.
	int mergedDim = ELEMENT_OF + (srcType & DIM_MASK);
	mergedType = mergedDim \| REFERENCE_KIND \| symbolTable.addType("java/lang/Object");
	}
	} else if ((srcType & DIM_MASK) != 0 \|\| (srcType & KIND_MASK) == REFERENCE_KIND) {
	// If srcType is any other reference or array type,
	// merge(srcType, dstType) = min(srcDdim, dstDim) \| java/lang/Object
	// where srcDim is the array dimension of srcType, minus 1 if srcType is an array type
	// with a non reference element type (and similarly for dstDim).
	int srcDim = srcType & DIM_MASK;
	if (srcDim != 0 && (srcType & KIND_MASK) != REFERENCE_KIND) {
	srcDim = ELEMENT_OF + srcDim;
	}
	int dstDim = dstType & DIM_MASK;
	if (dstDim != 0 && (dstType & KIND_MASK) != REFERENCE_KIND) {
	dstDim = ELEMENT_OF + dstDim;
	}
	mergedType =
	Math.min(srcDim, dstDim) \| REFERENCE_KIND \| symbolTable.addType("java/lang/Object");
	} else {
	// If srcType is any other type, merge(srcType, dstType) = TOP.
	mergedType = TOP;
	}
	} else if (dstType == NULL) {
	// If dstType is the NULL type, merge(srcType, dstType) = srcType, or TOP if srcType is not a
	// an array type or a reference type.
	mergedType =
	(srcType & DIM_MASK) != 0 \|\| (srcType & KIND_MASK) == REFERENCE_KIND ? srcType : TOP;
	} else {
	// If dstType is any other type, merge(srcType, dstType) = TOP whatever srcType.
	mergedType = TOP;
	}
	if (mergedType != dstType) {
	dstTypes[dstIndex] = mergedType;
	return true;
	}
	return false;
	}

	// -----------------------------------------------------------------------------------------------
	// Frame output methods, to generate StackMapFrame attributes
	// -----------------------------------------------------------------------------------------------

	/**
	* Makes the given {@link MethodWriter} visit the input frame of this {@link Frame}. The visit is
	* done with the {@link MethodWriter#visitFrameStart}, {@link MethodWriter#visitAbstractType} and
	* {@link MethodWriter#visitFrameEnd} methods.
	*
	* @param methodWriter the {@link MethodWriter} that should visit the input frame of this {@link
	* Frame}.
	*/
	final void accept(final MethodWriter methodWriter) {
	// Compute the number of locals, ignoring TOP types that are just after a LONG or a DOUBLE, and
	// all trailing TOP types.
	int[] localTypes = inputLocals;
	int numLocal = 0;
	int numTrailingTop = 0;
	int i = 0;
	while (i < localTypes.length) {
	int localType = localTypes[i];
	i += (localType == LONG \|\| localType == DOUBLE) ? 2 : 1;
	if (localType == TOP) {
	numTrailingTop++;
	} else {
	numLocal += numTrailingTop + 1;
	numTrailingTop = 0;
	}
	}
	// Compute the stack size, ignoring TOP types that are just after a LONG or a DOUBLE.
	int[] stackTypes = inputStack;
	int numStack = 0;
	i = 0;
	while (i < stackTypes.length) {
	int stackType = stackTypes[i];
	i += (stackType == LONG \|\| stackType == DOUBLE) ? 2 : 1;
	numStack++;
	}
	// Visit the frame and its content.
	int frameIndex = methodWriter.visitFrameStart(owner.bytecodeOffset, numLocal, numStack);
	i = 0;
	while (numLocal-- > 0) {
	int localType = localTypes[i];
	i += (localType == LONG \|\| localType == DOUBLE) ? 2 : 1;
	methodWriter.visitAbstractType(frameIndex++, localType);
	}
	i = 0;
	while (numStack-- > 0) {
	int stackType = stackTypes[i];
	i += (stackType == LONG \|\| stackType == DOUBLE) ? 2 : 1;
	methodWriter.visitAbstractType(frameIndex++, stackType);
	}
	methodWriter.visitFrameEnd();
	}

	/**
	* Put the given abstract type in the given ByteVector, using the JVMS verification_type_info
	* format used in StackMapTable attributes.
	*
	* @param symbolTable the type table to use to lookup and store type {@link Symbol}.
	* @param abstractType an abstract type, restricted to {@link Frame#CONSTANT_KIND}, {@link
	* Frame#REFERENCE_KIND} or {@link Frame#UNINITIALIZED_KIND} types.
	* @param output where the abstract type must be put.
	* @see <a href="https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.4">JVMS
	* 4.7.4</a>
	*/
	static void putAbstractType(
	final SymbolTable symbolTable, final int abstractType, final ByteVector output) {
	int arrayDimensions = (abstractType & Frame.DIM_MASK) >> DIM_SHIFT;
	if (arrayDimensions == 0) {
	int typeValue = abstractType & VALUE_MASK;
	switch (abstractType & KIND_MASK) {
	case CONSTANT_KIND:
	output.putByte(typeValue);
	break;
	case REFERENCE_KIND:
	output
	.putByte(ITEM_OBJECT)
	.putShort(symbolTable.addConstantClass(symbolTable.getType(typeValue).value).index);
	break;
	case UNINITIALIZED_KIND:
	output.putByte(ITEM_UNINITIALIZED).putShort((int) symbolTable.getType(typeValue).data);
	break;
	default:
	throw new AssertionError();
	}
	} else {
	// Case of an array type, we need to build its descriptor first.
	StringBuilder typeDescriptor = new StringBuilder();
	while (arrayDimensions-- > 0) {
	typeDescriptor.append('[');
	}
	if ((abstractType & KIND_MASK) == REFERENCE_KIND) {
	typeDescriptor
	.append('L')
	.append(symbolTable.getType(abstractType & VALUE_MASK).value)
	.append(';');
	} else {
	switch (abstractType & VALUE_MASK) {
	case Frame.ITEM_ASM_BOOLEAN:
	typeDescriptor.append('Z');
	break;
	case Frame.ITEM_ASM_BYTE:
	typeDescriptor.append('B');
	break;
	case Frame.ITEM_ASM_CHAR:
	typeDescriptor.append('C');
	break;
	case Frame.ITEM_ASM_SHORT:
	typeDescriptor.append('S');
	break;
	case Frame.ITEM_INTEGER:
	typeDescriptor.append('I');
	break;
	case Frame.ITEM_FLOAT:
	typeDescriptor.append('F');
	break;
	case Frame.ITEM_LONG:
	typeDescriptor.append('J');
	break;
	case Frame.ITEM_DOUBLE:
	typeDescriptor.append('D');
	break;
	default:
	throw new AssertionError();
	}
	}
	output
	.putByte(ITEM_OBJECT)
	.putShort(symbolTable.addConstantClass(typeDescriptor.toString()).index);
	}
	}
	}

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