http://git-wip-us.apache.org/repos/asf/tapestry-5/blob/1c71aec7/plastic/src/external/java/org/apache/tapestry5/internal/plastic/asm/Label.java ---------------------------------------------------------------------- diff --git a/plastic/src/external/java/org/apache/tapestry5/internal/plastic/asm/Label.java b/plastic/src/external/java/org/apache/tapestry5/internal/plastic/asm/Label.java old mode 100644 new mode 100755 index 57d771c..906ab98 --- a/plastic/src/external/java/org/apache/tapestry5/internal/plastic/asm/Label.java +++ b/plastic/src/external/java/org/apache/tapestry5/internal/plastic/asm/Label.java @@ -1,564 +1,621 @@ -/*** - * 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. - */ +// 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 org.apache.tapestry5.internal.plastic.asm; /** - * A label represents 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 + * 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 { - /** - * Indicates if this 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 DEBUG = 1; - - /** - * Indicates if the position of this label is known. - */ - static final int RESOLVED = 2; - - /** - * Indicates if this label has been updated, after instruction resizing. - */ - static final int RESIZED = 4; - - /** - * Indicates if this basic block has been pushed in the basic block stack. - * See {@link MethodWriter#visitMaxs visitMaxs}. - */ - static final int PUSHED = 8; - - /** - * Indicates if this label is the target of a jump instruction, or the start - * of an exception handler. - */ - static final int TARGET = 16; - - /** - * Indicates if a stack map frame must be stored for this label. - */ - static final int STORE = 32; - - /** - * Indicates if this label corresponds to a reachable basic block. - */ - static final int REACHABLE = 64; - - /** - * Indicates if this basic block ends with a JSR instruction. - */ - static final int JSR = 128; - - /** - * Indicates if this basic block ends with a RET instruction. - */ - static final int RET = 256; - - /** - * Indicates if this basic block is the start of a subroutine. - */ - static final int SUBROUTINE = 512; - - /** - * Indicates if this subroutine basic block has been visited by a - * visitSubroutine(null, ...) call. - */ - static final int VISITED = 1024; - - /** - * Indicates if this subroutine basic block has been visited by a - * visitSubroutine(!null, ...) call. - */ - static final int VISITED2 = 2048; - - /** - * Field used to associate user information to a 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 - * {@link org.objectweb.asm.tree.MethodNode#getLabelNode} method. - */ - public Object info; - - /** - * Flags that indicate the status of this label. - * - * @see #DEBUG - * @see #RESOLVED - * @see #RESIZED - * @see #PUSHED - * @see #TARGET - * @see #STORE - * @see #REACHABLE - * @see #JSR - * @see #RET - */ - int status; - - /** - * The line number corresponding to this label, if known. If there are - * several lines, each line is stored in a separate label, all linked via - * their next field (these links are created in ClassReader and removed just - * before visitLabel is called, so that this does not impact the rest of the - * code). - */ - int line; - - /** - * The position of this label in the code, if known. - */ - int position; - - /** - * Number of forward references to this label, times two. - */ - private int referenceCount; - - /** - * Informations about forward references. Each forward reference is - * described by two consecutive integers in this array: the first one is the - * position of the first byte of the bytecode instruction that contains the - * forward reference, while the second is the position of the first byte of - * the forward reference itself. In fact the sign of the first integer - * indicates if this reference uses 2 or 4 bytes, and its absolute value - * gives the position of the bytecode instruction. This array is also used - * as a bitset to store the subroutines to which a basic block belongs. This - * information is needed in {@linked MethodWriter#visitMaxs}, after all - * forward references have been resolved. Hence the same array can be used - * for both purposes without problems. - */ - private int[] srcAndRefPositions; - - // ------------------------------------------------------------------------ - - /* - * 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 by 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#visitMaxs}, 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. - */ - - /** - * Start of the output stack relatively to the input stack. The exact - * semantics of this field depends on the algorithm that is used. - * - * When only the maximum stack size is computed, this field is the number of - * elements in the input stack. - * - * When the stack map frames are completely computed, this field is the - * offset of the first output stack element relatively to the top of 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. - */ - int inputStackTop; - - /** - * Maximum height reached by the output stack, relatively to the top of the - * input stack. This maximum is always positive or null. - */ - int outputStackMax; - - /** - * Information about the input and output stack map frames of this basic - * block. This field is only used when {@link ClassWriter#COMPUTE_FRAMES} - * option is used. - */ - Frame frame; - - /** - * The successor of this label, in the order they are visited. This linked - * list does not include labels used for debug info only. If - * {@link ClassWriter#COMPUTE_FRAMES} option is used then, in addition, it - * does not contain successive labels that denote the same bytecode position - * (in this case only the first label appears in this list). - */ - Label successor; - - /** - * The successors of this node in the control flow graph. These successors - * are stored in a linked list of {@link Edge Edge} objects, linked to each - * other by their {@link Edge#next} field. - */ - Edge successors; - - /** - * The next basic block in the basic block stack. This stack is used in the - * main loop of the fix point algorithm used in the second step of the - * control flow analysis algorithms. It is also used in - * {@link #visitSubroutine} to avoid using a recursive method, and in - * ClassReader to temporarily store multiple source lines for a label. - * - * @see MethodWriter#visitMaxs - */ - Label next; - - // ------------------------------------------------------------------------ - // Constructor - // ------------------------------------------------------------------------ - - /** - * Constructs a new label. - */ - public 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 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 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"); } - - // ------------------------------------------------------------------------ - // Methods to compute offsets and to manage forward references - // ------------------------------------------------------------------------ - - /** - * Returns the 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 offset corresponding to this label. - * @throws IllegalStateException - * if this label is not resolved yet. - */ - public int getOffset() { - if ((status & RESOLVED) == 0) { - throw new IllegalStateException( - "Label offset position has not been resolved yet"); - } - return position; + 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; } - - /** - * Puts a reference to this label in the bytecode of a method. If the - * position of the label is known, the offset is computed and written - * directly. Otherwise, a null offset is written and a new forward reference - * is declared for this label. - * - * @param owner - * the code writer that calls this method. - * @param out - * the bytecode of the method. - * @param source - * the position of first byte of the bytecode instruction that - * contains this label. - * @param wideOffset - * <tt>true</tt> if the reference must be stored in 4 bytes, or - * <tt>false</tt> if it must be stored with 2 bytes. - * @throws IllegalArgumentException - * if this label has not been created by the given code writer. - */ - void put(final MethodWriter owner, final ByteVector out, final int source, - final boolean wideOffset) { - if ((status & RESOLVED) == 0) { - if (wideOffset) { - addReference(-1 - source, out.length); - out.putInt(-1); - } else { - addReference(source, out.length); - out.putShort(-1); - } - } else { - if (wideOffset) { - out.putInt(position - source); - } else { - out.putShort(position - source); - } + } + + /** + * 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); } + } } - - /** - * 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 offset of the reference can be, and - * must be, computed and stored directly. - * - * @param sourcePosition - * the position of the referencing instruction. This position - * will be used to compute the offset of this forward reference. - * @param referencePosition - * the position where the offset for this forward reference must - * be stored. - */ - private void addReference(final int sourcePosition, - final int referencePosition) { - if (srcAndRefPositions == null) { - srcAndRefPositions = new int[6]; - } - if (referenceCount >= srcAndRefPositions.length) { - int[] a = new int[srcAndRefPositions.length + 6]; - System.arraycopy(srcAndRefPositions, 0, a, 0, - srcAndRefPositions.length); - srcAndRefPositions = a; - } - srcAndRefPositions[referenceCount++] = sourcePosition; - srcAndRefPositions[referenceCount++] = referencePosition; + } + + // ----------------------------------------------------------------------------------------------- + // 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); + } } - - /** - * Resolves all forward references to this label. This method must be called - * when this label is added to the bytecode of the method, i.e. when its - * position becomes known. This method fills in the blanks that where left - * in the bytecode by each forward reference previously added to this label. - * - * @param owner - * the code writer that calls this method. - * @param position - * the position of this label in the bytecode. - * @param data - * the bytecode of the method. - * @return <tt>true</tt> 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 a pseudo instruction (using unused - * opcodes) using an unsigned two bytes offset. These pseudo - * instructions will be replaced with standard bytecode instructions - * with wider offsets (4 bytes instead of 2), in ClassReader. - * @throws IllegalArgumentException - * if this label has already been resolved, or if it has not - * been created by the given code writer. - */ - boolean resolve(final MethodWriter owner, final int position, - final byte[] data) { - boolean needUpdate = false; - this.status |= RESOLVED; - this.position = position; - int i = 0; - while (i < referenceCount) { - int source = srcAndRefPositions[i++]; - int reference = srcAndRefPositions[i++]; - int offset; - if (source >= 0) { - offset = position - source; - if (offset < Short.MIN_VALUE || offset > Short.MAX_VALUE) { - /* - * changes the opcode of the jump instruction, in order to - * be able to find it later (see resizeInstructions in - * MethodWriter). These temporary 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 = data[reference - 1] & 0xFF; - if (opcode <= Opcodes.JSR) { - // changes IFEQ ... JSR to opcodes 202 to 217 - data[reference - 1] = (byte) (opcode + 49); - } else { - // changes IFNULL and IFNONNULL to opcodes 218 and 219 - data[reference - 1] = (byte) (opcode + 20); - } - needUpdate = true; - } - data[reference++] = (byte) (offset >>> 8); - data[reference] = (byte) offset; - } else { - offset = position + source + 1; - data[reference++] = (byte) (offset >>> 24); - data[reference++] = (byte) (offset >>> 16); - data[reference++] = (byte) (offset >>> 8); - data[reference] = (byte) offset; - } - } - return needUpdate; + } + + /** + * 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]; } - - /** - * Returns the first label of the series to which this label belongs. For an - * isolated label or for the first label in a series of successive labels, - * this method returns the label itself. For other labels it returns the - * first label of the series. - * - * @return the first label of the series to which this label belongs. - */ - Label getFirst() { - return frame == null ? this : frame.owner; + 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; } - - // ------------------------------------------------------------------------ - // Methods related to subroutines - // ------------------------------------------------------------------------ - - /** - * Returns true is this basic block belongs to the given subroutine. - * - * @param id - * a subroutine id. - * @return true is this basic block belongs to the given subroutine. - */ - boolean inSubroutine(final long id) { - if ((status & Label.VISITED) != 0) { - return (srcAndRefPositions[(int) (id >>> 32)] & (int) id) != 0; - } - return false; + 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; } - - /** - * Returns true if this basic block and the given one belong to a common - * subroutine. - * - * @param block - * another basic block. - * @return true if this basic block and the given one belong to a common - * subroutine. - */ - boolean inSameSubroutine(final Label block) { - if ((status & VISITED) == 0 || (block.status & VISITED) == 0) { - return false; - } - for (int i = 0; i < srcAndRefPositions.length; ++i) { - if ((srcAndRefPositions[i] & block.srcAndRefPositions[i]) != 0) { - return true; - } + 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; } - return false; + 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; + } } - - /** - * Marks this basic block as belonging to the given subroutine. - * - * @param id - * a subroutine id. - * @param nbSubroutines - * the total number of subroutines in the method. - */ - void addToSubroutine(final long id, final int nbSubroutines) { - if ((status & VISITED) == 0) { - status |= VISITED; - srcAndRefPositions = new int[nbSubroutines / 32 + 1]; - } - srcAndRefPositions[(int) (id >>> 32)] |= (int) id; + 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 belong to a given subroutine, 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 - * block WITHOUT following any JSR target. - * - * @param JSR - * a JSR block that jumps to this subroutine. If this JSR is not - * null it is added to the successor of the RET blocks found in - * the subroutine. - * @param id - * the id of this subroutine. - * @param nbSubroutines - * the total number of subroutines in the method. - */ - void visitSubroutine(final Label JSR, final long id, final int nbSubroutines) { - // user managed stack of labels, to avoid using a recursive method - // (recursivity can lead to stack overflow with very large methods) - Label stack = this; - while (stack != null) { - // removes a label l from the stack - Label l = stack; - stack = l.next; - l.next = null; - - if (JSR != null) { - if ((l.status & VISITED2) != 0) { - continue; - } - l.status |= VISITED2; - // adds JSR to the successors of l, if it is a RET block - if ((l.status & RET) != 0) { - if (!l.inSameSubroutine(JSR)) { - Edge e = new Edge(); - e.info = l.inputStackTop; - e.successor = JSR.successors.successor; - e.next = l.successors; - l.successors = e; - } - } - } else { - // if the l block already belongs to subroutine 'id', continue - if (l.inSubroutine(id)) { - continue; - } - // marks the l block as belonging to subroutine 'id' - l.addToSubroutine(id, nbSubroutines); - } - // pushes each successor of l on the stack, except JSR targets - Edge e = l.successors; - while (e != null) { - // if the l block is a JSR block, then 'l.successors.next' leads - // to the JSR target (see {@link #visitJumpInsn}) and must - // therefore not be followed - if ((l.status & Label.JSR) == 0 || e != l.successors.next) { - // pushes e.successor on the stack if it not already added - if (e.successor.next == null) { - e.successor.next = stack; - stack = e.successor; - } - } - e = e.next; - } - } + } + + /** + * 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); } - - // ------------------------------------------------------------------------ - // Overriden 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); + // 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); + } }
http://git-wip-us.apache.org/repos/asf/tapestry-5/blob/1c71aec7/plastic/src/external/java/org/apache/tapestry5/internal/plastic/asm/MethodTooLargeException.java ---------------------------------------------------------------------- diff --git a/plastic/src/external/java/org/apache/tapestry5/internal/plastic/asm/MethodTooLargeException.java b/plastic/src/external/java/org/apache/tapestry5/internal/plastic/asm/MethodTooLargeException.java new file mode 100755 index 0000000..348de37 --- /dev/null +++ b/plastic/src/external/java/org/apache/tapestry5/internal/plastic/asm/MethodTooLargeException.java @@ -0,0 +1,99 @@ +// 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 org.apache.tapestry5.internal.plastic.asm; + +/** + * Exception thrown when the Code attribute of a method produced by a {@link ClassWriter} is too + * large. + * + * @author Jason Zaugg + */ +public final class MethodTooLargeException extends IndexOutOfBoundsException { + private static final long serialVersionUID = 6807380416709738314L; + + private final String className; + private final String methodName; + private final String descriptor; + private final int codeSize; + + /** + * Constructs a new {@link MethodTooLargeException}. + * + * @param className the internal name of the owner class. + * @param methodName the name of the method. + * @param descriptor the descriptor of the method. + * @param codeSize the size of the method's Code attribute, in bytes. + */ + public MethodTooLargeException( + final String className, + final String methodName, + final String descriptor, + final int codeSize) { + super("Method too large: " + className + "." + methodName + " " + descriptor); + this.className = className; + this.methodName = methodName; + this.descriptor = descriptor; + this.codeSize = codeSize; + } + + /** + * Returns the internal name of the owner class. + * + * @return the internal name of the owner class. + */ + public String getClassName() { + return className; + } + + /** + * Returns the name of the method. + * + * @return the name of the method. + */ + public String getMethodName() { + return methodName; + } + + /** + * Returns the descriptor of the method. + * + * @return the descriptor of the method. + */ + public String getDescriptor() { + return descriptor; + } + + /** + * Returns the size of the method's Code attribute, in bytes. + * + * @return the size of the method's Code attribute, in bytes. + */ + public int getCodeSize() { + return codeSize; + } +}