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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;

	/**
	* A position in the bytecode of a method. Labels are used for jump, goto, and switch instructions,
	* and for try catch blocks. A label designates the <i>instruction</i> that is just after. Note
	* however that there can be other elements between a label and the instruction it designates (such
	* as other labels, stack map frames, line numbers, etc.).
	*
	* @author Eric Bruneton
	*/
	public class Label {

	/**
	* A flag indicating that a label is only used for debug attributes. Such a label is not the start
	* of a basic block, the target of a jump instruction, or an exception handler. It can be safely
	* ignored in control flow graph analysis algorithms (for optimization purposes).
	*/
	static final int FLAG_DEBUG_ONLY = 1;

	/**
	* A flag indicating that a label is the target of a jump instruction, or the start of an
	* exception handler.
	*/
	static final int FLAG_JUMP_TARGET = 2;

	/** A flag indicating that the bytecode offset of a label is known. */
	static final int FLAG_RESOLVED = 4;

	/** A flag indicating that a label corresponds to a reachable basic block. */
	static final int FLAG_REACHABLE = 8;

	/**
	* A flag indicating that the basic block corresponding to a label ends with a subroutine call. By
	* construction in {@link MethodWriter#visitJumpInsn}, labels with this flag set have at least two
	* outgoing edges:
	*
	* <ul>
	* <li>the first one corresponds to the instruction that follows the jsr instruction in the
	* bytecode, i.e. where execution continues when it returns from the jsr call. This is a
	* virtual control flow edge, since execution never goes directly from the jsr to the next
	* instruction. Instead, it goes to the subroutine and eventually returns to the instruction
	* following the jsr. This virtual edge is used to compute the real outgoing edges of the
	* basic blocks ending with a ret instruction, in {@link #addSubroutineRetSuccessors}.
	* <li>the second one corresponds to the target of the jsr instruction,
	* </ul>
	*/
	static final int FLAG_SUBROUTINE_CALLER = 16;

	/**
	* A flag indicating that the basic block corresponding to a label is the start of a subroutine.
	*/
	static final int FLAG_SUBROUTINE_START = 32;

	/** A flag indicating that the basic block corresponding to a label is the end of a subroutine. */
	static final int FLAG_SUBROUTINE_END = 64;

	/**
	* The number of elements to add to the {@link #otherLineNumbers} array when it needs to be
	* resized to store a new source line number.
	*/
	static final int LINE_NUMBERS_CAPACITY_INCREMENT = 4;

	/**
	* The number of elements to add to the {@link #forwardReferences} array when it needs to be
	* resized to store a new forward reference.
	*/
	static final int FORWARD_REFERENCES_CAPACITY_INCREMENT = 6;

	/**
	* The bit mask to extract the type of a forward reference to this label. The extracted type is
	* either {@link #FORWARD_REFERENCE_TYPE_SHORT} or {@link #FORWARD_REFERENCE_TYPE_WIDE}.
	*
	* @see #forwardReferences
	*/
	static final int FORWARD_REFERENCE_TYPE_MASK = 0xF0000000;

	/**
	* The type of forward references stored with two bytes in the bytecode. This is the case, for
	* instance, of a forward reference from an ifnull instruction.
	*/
	static final int FORWARD_REFERENCE_TYPE_SHORT = 0x10000000;

	/**
	* The type of forward references stored in four bytes in the bytecode. This is the case, for
	* instance, of a forward reference from a lookupswitch instruction.
	*/
	static final int FORWARD_REFERENCE_TYPE_WIDE = 0x20000000;

	/**
	* The bit mask to extract the 'handle' of a forward reference to this label. The extracted handle
	* is the bytecode offset where the forward reference value is stored (using either 2 or 4 bytes,
	* as indicated by the {@link #FORWARD_REFERENCE_TYPE_MASK}).
	*
	* @see #forwardReferences
	*/
	static final int FORWARD_REFERENCE_HANDLE_MASK = 0x0FFFFFFF;

	/**
	* A sentinel element used to indicate the end of a list of labels.
	*
	* @see #nextListElement
	*/
	static final Label EMPTY_LIST = new Label();

	/**
	* A user managed state associated with this label. Warning: this field is used by the ASM tree
	* package. In order to use it with the ASM tree package you must override the getLabelNode method
	* in MethodNode.
	*/
	public Object info;

	/**
	* The type and status of this label or its corresponding basic block. Must be zero or more of
	* {@link #FLAG_DEBUG_ONLY}, {@link #FLAG_JUMP_TARGET}, {@link #FLAG_RESOLVED}, {@link
	* #FLAG_REACHABLE}, {@link #FLAG_SUBROUTINE_CALLER}, {@link #FLAG_SUBROUTINE_START}, {@link
	* #FLAG_SUBROUTINE_END}.
	*/
	short flags;

	/**
	* The source line number corresponding to this label, or 0. If there are several source line
	* numbers corresponding to this label, the first one is stored in this field, and the remaining
	* ones are stored in {@link #otherLineNumbers}.
	*/
	private short lineNumber;

	/**
	* The source line numbers corresponding to this label, in addition to {@link #lineNumber}, or
	* null. The first element of this array is the number n of source line numbers it contains, which
	* are stored between indices 1 and n (inclusive).
	*/
	private int[] otherLineNumbers;

	/**
	* The offset of this label in the bytecode of its method, in bytes. This value is set if and only
	* if the {@link #FLAG_RESOLVED} flag is set.
	*/
	int bytecodeOffset;

	/**
	* The forward references to this label. The first element is the number of forward references,
	* times 2 (this corresponds to the index of the last element actually used in this array). Then,
	* each forward reference is described with two consecutive integers noted
	* 'sourceInsnBytecodeOffset' and 'reference':
	*
	* <ul>
	* <li>'sourceInsnBytecodeOffset' is the bytecode offset of the instruction that contains the
	* forward reference,
	* <li>'reference' contains the type and the offset in the bytecode where the forward reference
	* value must be stored, which can be extracted with {@link #FORWARD_REFERENCE_TYPE_MASK}
	* and {@link #FORWARD_REFERENCE_HANDLE_MASK}.
	* </ul>
	*
	* <p>For instance, for an ifnull instruction at bytecode offset x, 'sourceInsnBytecodeOffset' is
	* equal to x, and 'reference' is of type {@link #FORWARD_REFERENCE_TYPE_SHORT} with value x + 1
	* (because the ifnull instruction uses a 2 bytes bytecode offset operand stored one byte after
	* the start of the instruction itself). For the default case of a lookupswitch instruction at
	* bytecode offset x, 'sourceInsnBytecodeOffset' is equal to x, and 'reference' is of type {@link
	* #FORWARD_REFERENCE_TYPE_WIDE} with value between x + 1 and x + 4 (because the lookupswitch
	* instruction uses a 4 bytes bytecode offset operand stored one to four bytes after the start of
	* the instruction itself).
	*/
	private int[] forwardReferences;

	// -----------------------------------------------------------------------------------------------

	// Fields for the control flow and data flow graph analysis algorithms (used to compute the
	// maximum stack size or the stack map frames). A control flow graph contains one node per "basic
	// block", and one edge per "jump" from one basic block to another. Each node (i.e., each basic
	// block) is represented with the Label object that corresponds to the first instruction of this
	// basic block. Each node also stores the list of its successors in the graph, as a linked list of
	// Edge objects.
	//
	// The control flow analysis algorithms used to compute the maximum stack size or the stack map
	// frames are similar and use two steps. The first step, during the visit of each instruction,
	// builds information about the state of the local variables and the operand stack at the end of
	// each basic block, called the "output frame", <i>relatively</i> to the frame state at the
	// beginning of the basic block, which is called the "input frame", and which is <i>unknown</i>
	// during this step. The second step, in {@link MethodWriter#computeAllFrames} and {@link
	// MethodWriter#computeMaxStackAndLocal}, is a fix point algorithm
	// that computes information about the input frame of each basic block, from the input state of
	// the first basic block (known from the method signature), and by the using the previously
	// computed relative output frames.
	//
	// The algorithm used to compute the maximum stack size only computes the relative output and
	// absolute input stack heights, while the algorithm used to compute stack map frames computes
	// relative output frames and absolute input frames.

	/**
	* The number of elements in the input stack of the basic block corresponding to this label. This
	* field is computed in {@link MethodWriter#computeMaxStackAndLocal}.
	*/
	short inputStackSize;

	/**
	* The number of elements in the output stack, at the end of the basic block corresponding to this
	* label. This field is only computed for basic blocks that end with a RET instruction.
	*/
	short outputStackSize;

	/**
	* The maximum height reached by the output stack, relatively to the top of the input stack, in
	* the basic block corresponding to this label. This maximum is always positive or {@literal
	* null}.
	*/
	short outputStackMax;

	/**
	* The id of the subroutine to which this basic block belongs, or 0. If the basic block belongs to
	* several subroutines, this is the id of the "oldest" subroutine that contains it (with the
	* convention that a subroutine calling another one is "older" than the callee). This field is
	* computed in {@link MethodWriter#computeMaxStackAndLocal}, if the method contains JSR
	* instructions.
	*/
	short subroutineId;

	/**
	* The input and output stack map frames of the basic block corresponding to this label. This
	* field is only used when the {@link MethodWriter#COMPUTE_ALL_FRAMES} or {@link
	* MethodWriter#COMPUTE_INSERTED_FRAMES} option is used.
	*/
	Frame frame;

	/**
	* The successor of this label, in the order they are visited in {@link MethodVisitor#visitLabel}.
	* This linked list does not include labels used for debug info only. If the {@link
	* MethodWriter#COMPUTE_ALL_FRAMES} or {@link MethodWriter#COMPUTE_INSERTED_FRAMES} option is used
	* then it does not contain either successive labels that denote the same bytecode offset (in this
	* case only the first label appears in this list).
	*/
	Label nextBasicBlock;

	/**
	* The outgoing edges of the basic block corresponding to this label, in the control flow graph of
	* its method. These edges are stored in a linked list of {@link Edge} objects, linked to each
	* other by their {@link Edge#nextEdge} field.
	*/
	Edge outgoingEdges;

	/**
	* The next element in the list of labels to which this label belongs, or {@literal null} if it
	* does not belong to any list. All lists of labels must end with the {@link #EMPTY_LIST}
	* sentinel, in order to ensure that this field is null if and only if this label does not belong
	* to a list of labels. Note that there can be several lists of labels at the same time, but that
	* a label can belong to at most one list at a time (unless some lists share a common tail, but
	* this is not used in practice).
	*
	* <p>List of labels are used in {@link MethodWriter#computeAllFrames} and {@link
	* MethodWriter#computeMaxStackAndLocal} to compute stack map frames and the maximum stack size,
	* respectively, as well as in {@link #markSubroutine} and {@link #addSubroutineRetSuccessors} to
	* compute the basic blocks belonging to subroutines and their outgoing edges. Outside of these
	* methods, this field should be null (this property is a precondition and a postcondition of
	* these methods).
	*/
	Label nextListElement;

	// -----------------------------------------------------------------------------------------------
	// Constructor and accessors
	// -----------------------------------------------------------------------------------------------

	/** Constructs a new label. */
	public Label() {
	// Nothing to do.
	}

	/**
	* Returns the bytecode offset corresponding to this label. This offset is computed from the start
	* of the method's bytecode. <i>This method is intended for {@link Attribute} sub classes, and is
	* normally not needed by class generators or adapters.</i>
	*
	* @return the bytecode offset corresponding to this label.
	* @throws IllegalStateException if this label is not resolved yet.
	*/
	public int getOffset() {
	if ((flags & FLAG_RESOLVED) == 0) {
	throw new IllegalStateException("Label offset position has not been resolved yet");
	}
	return bytecodeOffset;
	}

	/**
	* Returns the "canonical" {@link Label} instance corresponding to this label's bytecode offset,
	* if known, otherwise the label itself. The canonical instance is the first label (in the order
	* of their visit by {@link MethodVisitor#visitLabel}) corresponding to this bytecode offset. It
	* cannot be known for labels which have not been visited yet.
	*
	* <p><i>This method should only be used when the {@link MethodWriter#COMPUTE_ALL_FRAMES} option
	* is used.</i>
	*
	* @return the label itself if {@link #frame} is null, otherwise the Label's frame owner. This
	* corresponds to the "canonical" label instance described above thanks to the way the label
	* frame is set in {@link MethodWriter#visitLabel}.
	*/
	final Label getCanonicalInstance() {
	return frame == null ? this : frame.owner;
	}

	// -----------------------------------------------------------------------------------------------
	// Methods to manage line numbers
	// -----------------------------------------------------------------------------------------------

	/**
	* Adds a source line number corresponding to this label.
	*
	* @param lineNumber a source line number (which should be strictly positive).
	*/
	final void addLineNumber(final int lineNumber) {
	if (this.lineNumber == 0) {
	this.lineNumber = (short) lineNumber;
	} else {
	if (otherLineNumbers == null) {
	otherLineNumbers = new int[LINE_NUMBERS_CAPACITY_INCREMENT];
	}
	int otherLineNumberIndex = ++otherLineNumbers[0];
	if (otherLineNumberIndex >= otherLineNumbers.length) {
	int[] newLineNumbers = new int[otherLineNumbers.length + LINE_NUMBERS_CAPACITY_INCREMENT];
	System.arraycopy(otherLineNumbers, 0, newLineNumbers, 0, otherLineNumbers.length);
	otherLineNumbers = newLineNumbers;
	}
	otherLineNumbers[otherLineNumberIndex] = lineNumber;
	}
	}

	/**
	* Makes the given visitor visit this label and its source line numbers, if applicable.
	*
	* @param methodVisitor a method visitor.
	* @param visitLineNumbers whether to visit of the label's source line numbers, if any.
	*/
	final void accept(final MethodVisitor methodVisitor, final boolean visitLineNumbers) {
	methodVisitor.visitLabel(this);
	if (visitLineNumbers && lineNumber != 0) {
	methodVisitor.visitLineNumber(lineNumber & 0xFFFF, this);
	if (otherLineNumbers != null) {
	for (int i = 1; i <= otherLineNumbers[0]; ++i) {
	methodVisitor.visitLineNumber(otherLineNumbers[i], this);
	}
	}
	}
	}

	// -----------------------------------------------------------------------------------------------
	// Methods to compute offsets and to manage forward references
	// -----------------------------------------------------------------------------------------------

	/**
	* Puts a reference to this label in the bytecode of a method. If the bytecode offset of the label
	* is known, the relative bytecode offset between the label and the instruction referencing it is
	* computed and written directly. Otherwise, a null relative offset is written and a new forward
	* reference is declared for this label.
	*
	* @param code the bytecode of the method. This is where the reference is appended.
	* @param sourceInsnBytecodeOffset the bytecode offset of the instruction that contains the
	* reference to be appended.
	* @param wideReference whether the reference must be stored in 4 bytes (instead of 2 bytes).
	*/
	final void put(
	final ByteVector code, final int sourceInsnBytecodeOffset, final boolean wideReference) {
	if ((flags & FLAG_RESOLVED) == 0) {
	if (wideReference) {
	addForwardReference(sourceInsnBytecodeOffset, FORWARD_REFERENCE_TYPE_WIDE, code.length);
	code.putInt(-1);
	} else {
	addForwardReference(sourceInsnBytecodeOffset, FORWARD_REFERENCE_TYPE_SHORT, code.length);
	code.putShort(-1);
	}
	} else {
	if (wideReference) {
	code.putInt(bytecodeOffset - sourceInsnBytecodeOffset);
	} else {
	code.putShort(bytecodeOffset - sourceInsnBytecodeOffset);
	}
	}
	}

	/**
	* Adds a forward reference to this label. This method must be called only for a true forward
	* reference, i.e. only if this label is not resolved yet. For backward references, the relative
	* bytecode offset of the reference can be, and must be, computed and stored directly.
	*
	* @param sourceInsnBytecodeOffset the bytecode offset of the instruction that contains the
	* reference stored at referenceHandle.
	* @param referenceType either {@link #FORWARD_REFERENCE_TYPE_SHORT} or {@link
	* #FORWARD_REFERENCE_TYPE_WIDE}.
	* @param referenceHandle the offset in the bytecode where the forward reference value must be
	* stored.
	*/
	private void addForwardReference(
	final int sourceInsnBytecodeOffset, final int referenceType, final int referenceHandle) {
	if (forwardReferences == null) {
	forwardReferences = new int[FORWARD_REFERENCES_CAPACITY_INCREMENT];
	}
	int lastElementIndex = forwardReferences[0];
	if (lastElementIndex + 2 >= forwardReferences.length) {
	int[] newValues = new int[forwardReferences.length + FORWARD_REFERENCES_CAPACITY_INCREMENT];
	System.arraycopy(forwardReferences, 0, newValues, 0, forwardReferences.length);
	forwardReferences = newValues;
	}
	forwardReferences[++lastElementIndex] = sourceInsnBytecodeOffset;
	forwardReferences[++lastElementIndex] = referenceType \| referenceHandle;
	forwardReferences[0] = lastElementIndex;
	}

	/**
	* Sets the bytecode offset of this label to the given value and resolves the forward references
	* to this label, if any. This method must be called when this label is added to the bytecode of
	* the method, i.e. when its bytecode offset becomes known. This method fills in the blanks that
	* where left in the bytecode by each forward reference previously added to this label.
	*
	* @param code the bytecode of the method.
	* @param bytecodeOffset the bytecode offset of this label.
	* @return {@literal true} if a blank that was left for this label was too small to store the
	* offset. In such a case the corresponding jump instruction is replaced with an equivalent
	* ASM specific instruction using an unsigned two bytes offset. These ASM specific
	* instructions are later replaced with standard bytecode instructions with wider offsets (4
	* bytes instead of 2), in ClassReader.
	*/
	final boolean resolve(final byte[] code, final int bytecodeOffset) {
	this.flags \|= FLAG_RESOLVED;
	this.bytecodeOffset = bytecodeOffset;
	if (forwardReferences == null) {
	return false;
	}
	boolean hasAsmInstructions = false;
	for (int i = forwardReferences[0]; i > 0; i -= 2) {
	final int sourceInsnBytecodeOffset = forwardReferences[i - 1];
	final int reference = forwardReferences[i];
	final int relativeOffset = bytecodeOffset - sourceInsnBytecodeOffset;
	int handle = reference & FORWARD_REFERENCE_HANDLE_MASK;
	if ((reference & FORWARD_REFERENCE_TYPE_MASK) == FORWARD_REFERENCE_TYPE_SHORT) {
	if (relativeOffset < Short.MIN_VALUE \|\| relativeOffset > Short.MAX_VALUE) {
	// Change the opcode of the jump instruction, in order to be able to find it later in
	// ClassReader. These ASM specific opcodes are similar to jump instruction opcodes, except
	// that the 2 bytes offset is unsigned (and can therefore represent values from 0 to
	// 65535, which is sufficient since the size of a method is limited to 65535 bytes).
	int opcode = code[sourceInsnBytecodeOffset] & 0xFF;
	if (opcode < Opcodes.IFNULL) {
	// Change IFEQ ... JSR to ASM_IFEQ ... ASM_JSR.
	code[sourceInsnBytecodeOffset] = (byte) (opcode + Constants.ASM_OPCODE_DELTA);
	} else {
	// Change IFNULL and IFNONNULL to ASM_IFNULL and ASM_IFNONNULL.
	code[sourceInsnBytecodeOffset] = (byte) (opcode + Constants.ASM_IFNULL_OPCODE_DELTA);
	}
	hasAsmInstructions = true;
	}
	code[handle++] = (byte) (relativeOffset >>> 8);
	code[handle] = (byte) relativeOffset;
	} else {
	code[handle++] = (byte) (relativeOffset >>> 24);
	code[handle++] = (byte) (relativeOffset >>> 16);
	code[handle++] = (byte) (relativeOffset >>> 8);
	code[handle] = (byte) relativeOffset;
	}
	}
	return hasAsmInstructions;
	}

	// -----------------------------------------------------------------------------------------------
	// Methods related to subroutines
	// -----------------------------------------------------------------------------------------------

	/**
	* Finds the basic blocks that belong to the subroutine starting with the basic block
	* corresponding to this label, and marks these blocks as belonging to this subroutine. This
	* method follows the control flow graph to find all the blocks that are reachable from the
	* current basic block WITHOUT following any jsr target.
	*
	* <p>Note: a precondition and postcondition of this method is that all labels must have a null
	* {@link #nextListElement}.
	*
	* @param subroutineId the id of the subroutine starting with the basic block corresponding to
	* this label.
	*/
	final void markSubroutine(final short subroutineId) {
	// Data flow algorithm: put this basic block in a list of blocks to process (which are blocks
	// belonging to subroutine subroutineId) and, while there are blocks to process, remove one from
	// the list, mark it as belonging to the subroutine, and add its successor basic blocks in the
	// control flow graph to the list of blocks to process (if not already done).
	Label listOfBlocksToProcess = this;
	listOfBlocksToProcess.nextListElement = EMPTY_LIST;
	while (listOfBlocksToProcess != EMPTY_LIST) {
	// Remove a basic block from the list of blocks to process.
	Label basicBlock = listOfBlocksToProcess;
	listOfBlocksToProcess = listOfBlocksToProcess.nextListElement;
	basicBlock.nextListElement = null;

	// If it is not already marked as belonging to a subroutine, mark it as belonging to
	// subroutineId and add its successors to the list of blocks to process (unless already done).
	if (basicBlock.subroutineId == 0) {
	basicBlock.subroutineId = subroutineId;
	listOfBlocksToProcess = basicBlock.pushSuccessors(listOfBlocksToProcess);
	}
	}
	}

	/**
	* Finds the basic blocks that end a subroutine starting with the basic block corresponding to
	* this label and, for each one of them, adds an outgoing edge to the basic block following the
	* given subroutine call. In other words, completes the control flow graph by adding the edges
	* corresponding to the return from this subroutine, when called from the given caller basic
	* block.
	*
	* <p>Note: a precondition and postcondition of this method is that all labels must have a null
	* {@link #nextListElement}.
	*
	* @param subroutineCaller a basic block that ends with a jsr to the basic block corresponding to
	* this label. This label is supposed to correspond to the start of a subroutine.
	*/
	final void addSubroutineRetSuccessors(final Label subroutineCaller) {
	// Data flow algorithm: put this basic block in a list blocks to process (which are blocks
	// belonging to a subroutine starting with this label) and, while there are blocks to process,
	// remove one from the list, put it in a list of blocks that have been processed, add a return
	// edge to the successor of subroutineCaller if applicable, and add its successor basic blocks
	// in the control flow graph to the list of blocks to process (if not already done).
	Label listOfProcessedBlocks = EMPTY_LIST;
	Label listOfBlocksToProcess = this;
	listOfBlocksToProcess.nextListElement = EMPTY_LIST;
	while (listOfBlocksToProcess != EMPTY_LIST) {
	// Move a basic block from the list of blocks to process to the list of processed blocks.
	Label basicBlock = listOfBlocksToProcess;
	listOfBlocksToProcess = basicBlock.nextListElement;
	basicBlock.nextListElement = listOfProcessedBlocks;
	listOfProcessedBlocks = basicBlock;

	// Add an edge from this block to the successor of the caller basic block, if this block is
	// the end of a subroutine and if this block and subroutineCaller do not belong to the same
	// subroutine.
	if ((basicBlock.flags & FLAG_SUBROUTINE_END) != 0
	&& basicBlock.subroutineId != subroutineCaller.subroutineId) {
	basicBlock.outgoingEdges =
	new Edge(
	basicBlock.outputStackSize,
	// By construction, the first outgoing edge of a basic block that ends with a jsr
	// instruction leads to the jsr continuation block, i.e. where execution continues
	// when ret is called (see {@link #FLAG_SUBROUTINE_CALLER}).
	subroutineCaller.outgoingEdges.successor,
	basicBlock.outgoingEdges);
	}
	// Add its successors to the list of blocks to process. Note that {@link #pushSuccessors} does
	// not push basic blocks which are already in a list. Here this means either in the list of
	// blocks to process, or in the list of already processed blocks. This second list is
	// important to make sure we don't reprocess an already processed block.
	listOfBlocksToProcess = basicBlock.pushSuccessors(listOfBlocksToProcess);
	}
	// Reset the {@link #nextListElement} of all the basic blocks that have been processed to null,
	// so that this method can be called again with a different subroutine or subroutine caller.
	while (listOfProcessedBlocks != EMPTY_LIST) {
	Label newListOfProcessedBlocks = listOfProcessedBlocks.nextListElement;
	listOfProcessedBlocks.nextListElement = null;
	listOfProcessedBlocks = newListOfProcessedBlocks;
	}
	}

	/**
	* Adds the successors of this label in the method's control flow graph (except those
	* corresponding to a jsr target, and those already in a list of labels) to the given list of
	* blocks to process, and returns the new list.
	*
	* @param listOfLabelsToProcess a list of basic blocks to process, linked together with their
	* {@link #nextListElement} field.
	* @return the new list of blocks to process.
	*/
	private Label pushSuccessors(final Label listOfLabelsToProcess) {
	Label newListOfLabelsToProcess = listOfLabelsToProcess;
	Edge outgoingEdge = outgoingEdges;
	while (outgoingEdge != null) {
	// By construction, the second outgoing edge of a basic block that ends with a jsr instruction
	// leads to the jsr target (see {@link #FLAG_SUBROUTINE_CALLER}).
	boolean isJsrTarget =
	(flags & Label.FLAG_SUBROUTINE_CALLER) != 0 && outgoingEdge == outgoingEdges.nextEdge;
	if (!isJsrTarget && outgoingEdge.successor.nextListElement == null) {
	// Add this successor to the list of blocks to process, if it does not already belong to a
	// list of labels.
	outgoingEdge.successor.nextListElement = newListOfLabelsToProcess;
	newListOfLabelsToProcess = outgoingEdge.successor;
	}
	outgoingEdge = outgoingEdge.nextEdge;
	}
	return newListOfLabelsToProcess;
	}

	// -----------------------------------------------------------------------------------------------
	// Overridden Object methods
	// -----------------------------------------------------------------------------------------------

	/**
	* Returns a string representation of this label.
	*
	* @return a string representation of this label.
	*/
	@Override
	public String toString() {
	return "L" + System.identityHashCode(this);
	}
	}

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