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Posted to commits@tajo.apache.org by hy...@apache.org on 2014/08/23 19:38:06 UTC
[17/25] TAJO-906: Runtime code generation for evaluating expression
trees.
http://git-wip-us.apache.org/repos/asf/tajo/blob/7603a3d4/tajo-thirdparty/asm/src/main/java/org/apache/tajo/org/objectweb/asm/Label.java
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diff --git a/tajo-thirdparty/asm/src/main/java/org/apache/tajo/org/objectweb/asm/Label.java b/tajo-thirdparty/asm/src/main/java/org/apache/tajo/org/objectweb/asm/Label.java
new file mode 100644
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--- /dev/null
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+/***
+ * 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.tajo.org.objectweb.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
+ * 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.apache.tajo.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.
+ */
+ 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.
+ *
+ * @see MethodWriter#visitMaxs
+ */
+ Label next;
+
+ // ------------------------------------------------------------------------
+ // Constructor
+ // ------------------------------------------------------------------------
+
+ /**
+ * Constructs a new label.
+ */
+ public Label() {
+ }
+
+ // ------------------------------------------------------------------------
+ // 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;
+ }
+
+ /**
+ * 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);
+ }
+ }
+ }
+
+ /**
+ * 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;
+ }
+
+ /**
+ * 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 to
+ * 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 need to be replaced with true instructions with
+ * wider offsets (4 bytes instead of 2). This is done in
+ * {@link MethodWriter#resizeInstructions}.
+ * @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;
+ }
+
+ /**
+ * 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 !ClassReader.FRAMES || frame == null ? this : frame.owner;
+ }
+
+ // ------------------------------------------------------------------------
+ // 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;
+ }
+
+ /**
+ * 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;
+ }
+ }
+ return false;
+ }
+
+ /**
+ * 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 - 1) / 32 + 1];
+ }
+ srcAndRefPositions[(int) (id >>> 32)] |= (int) id;
+ }
+
+ /**
+ * 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;
+ }
+ }
+ }
+
+ // ------------------------------------------------------------------------
+ // 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);
+ }
+}
http://git-wip-us.apache.org/repos/asf/tajo/blob/7603a3d4/tajo-thirdparty/asm/src/main/java/org/apache/tajo/org/objectweb/asm/MethodVisitor.java
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diff --git a/tajo-thirdparty/asm/src/main/java/org/apache/tajo/org/objectweb/asm/MethodVisitor.java b/tajo-thirdparty/asm/src/main/java/org/apache/tajo/org/objectweb/asm/MethodVisitor.java
new file mode 100644
index 0000000..1d6758e
--- /dev/null
+++ b/tajo-thirdparty/asm/src/main/java/org/apache/tajo/org/objectweb/asm/MethodVisitor.java
@@ -0,0 +1,662 @@
+/***
+ * 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.tajo.org.objectweb.asm;
+
+/**
+ * A visitor to visit a Java method. The methods of this class must be called in
+ * the following order: [ <tt>visitAnnotationDefault</tt> ] (
+ * <tt>visitAnnotation</tt> | <tt>visitParameterAnnotation</tt> |
+ * <tt>visitAttribute</tt> )* [ <tt>visitCode</tt> ( <tt>visitFrame</tt> |
+ * <tt>visit</tt><i>X</i>Insn</tt> | <tt>visitLabel</tt> |
+ * <tt>visitTryCatchBlock</tt> | <tt>visitLocalVariable</tt> |
+ * <tt>visitLineNumber</tt> )* <tt>visitMaxs</tt> ] <tt>visitEnd</tt>. In
+ * addition, the <tt>visit</tt><i>X</i>Insn</tt> and <tt>visitLabel</tt> methods
+ * must be called in the sequential order of the bytecode instructions of the
+ * visited code, <tt>visitTryCatchBlock</tt> must be called <i>before</i> the
+ * labels passed as arguments have been visited, and the
+ * <tt>visitLocalVariable</tt> and <tt>visitLineNumber</tt> methods must be
+ * called <i>after</i> the labels passed as arguments have been visited.
+ *
+ * @author Eric Bruneton
+ */
+public abstract class MethodVisitor {
+
+ /**
+ * The ASM API version implemented by this visitor. The value of this field
+ * must be one of {@link Opcodes#ASM4}.
+ */
+ protected final int api;
+
+ /**
+ * The method visitor to which this visitor must delegate method calls. May
+ * be null.
+ */
+ protected MethodVisitor mv;
+
+ /**
+ * Constructs a new {@link MethodVisitor}.
+ *
+ * @param api
+ * the ASM API version implemented by this visitor. Must be one
+ * of {@link Opcodes#ASM4}.
+ */
+ public MethodVisitor(final int api) {
+ this(api, null);
+ }
+
+ /**
+ * Constructs a new {@link MethodVisitor}.
+ *
+ * @param api
+ * the ASM API version implemented by this visitor. Must be one
+ * of {@link Opcodes#ASM4}.
+ * @param mv
+ * the method visitor to which this visitor must delegate method
+ * calls. May be null.
+ */
+ public MethodVisitor(final int api, final MethodVisitor mv) {
+ if (api != Opcodes.ASM4) {
+ throw new IllegalArgumentException();
+ }
+ this.api = api;
+ this.mv = mv;
+ }
+
+ // -------------------------------------------------------------------------
+ // Annotations and non standard attributes
+ // -------------------------------------------------------------------------
+
+ /**
+ * Visits the default value of this annotation interface method.
+ *
+ * @return a visitor to the visit the actual default value of this
+ * annotation interface method, or <tt>null</tt> if this visitor is
+ * not interested in visiting this default value. The 'name'
+ * parameters passed to the methods of this annotation visitor are
+ * ignored. Moreover, exacly one visit method must be called on this
+ * annotation visitor, followed by visitEnd.
+ */
+ public AnnotationVisitor visitAnnotationDefault() {
+ if (mv != null) {
+ return mv.visitAnnotationDefault();
+ }
+ return null;
+ }
+
+ /**
+ * Visits an annotation of this method.
+ *
+ * @param desc
+ * the class descriptor of the annotation class.
+ * @param visible
+ * <tt>true</tt> if the annotation is visible at runtime.
+ * @return a visitor to visit the annotation values, or <tt>null</tt> if
+ * this visitor is not interested in visiting this annotation.
+ */
+ public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
+ if (mv != null) {
+ return mv.visitAnnotation(desc, visible);
+ }
+ return null;
+ }
+
+ /**
+ * Visits an annotation of a parameter this method.
+ *
+ * @param parameter
+ * the parameter index.
+ * @param desc
+ * the class descriptor of the annotation class.
+ * @param visible
+ * <tt>true</tt> if the annotation is visible at runtime.
+ * @return a visitor to visit the annotation values, or <tt>null</tt> if
+ * this visitor is not interested in visiting this annotation.
+ */
+ public AnnotationVisitor visitParameterAnnotation(int parameter,
+ String desc, boolean visible) {
+ if (mv != null) {
+ return mv.visitParameterAnnotation(parameter, desc, visible);
+ }
+ return null;
+ }
+
+ /**
+ * Visits a non standard attribute of this method.
+ *
+ * @param attr
+ * an attribute.
+ */
+ public void visitAttribute(Attribute attr) {
+ if (mv != null) {
+ mv.visitAttribute(attr);
+ }
+ }
+
+ /**
+ * Starts the visit of the method's code, if any (i.e. non abstract method).
+ */
+ public void visitCode() {
+ if (mv != null) {
+ mv.visitCode();
+ }
+ }
+
+ /**
+ * Visits the current state of the local variables and operand stack
+ * elements. This method must(*) be called <i>just before</i> any
+ * instruction <b>i</b> that follows an unconditional branch instruction
+ * such as GOTO or THROW, that is the target of a jump instruction, or that
+ * starts an exception handler block. The visited types must describe the
+ * values of the local variables and of the operand stack elements <i>just
+ * before</i> <b>i</b> is executed.<br>
+ * <br>
+ * (*) this is mandatory only for classes whose version is greater than or
+ * equal to {@link Opcodes#V1_6 V1_6}. <br>
+ * <br>
+ * The frames of a method must be given either in expanded form, or in
+ * compressed form (all frames must use the same format, i.e. you must not
+ * mix expanded and compressed frames within a single method):
+ * <ul>
+ * <li>In expanded form, all frames must have the F_NEW type.</li>
+ * <li>In compressed form, frames are basically "deltas" from the state of
+ * the previous frame:
+ * <ul>
+ * <li>{@link Opcodes#F_SAME} representing frame with exactly the same
+ * locals as the previous frame and with the empty stack.</li>
+ * <li>{@link Opcodes#F_SAME1} representing frame with exactly the same
+ * locals as the previous frame and with single value on the stack (
+ * <code>nStack</code> is 1 and <code>stack[0]</code> contains value for the
+ * type of the stack item).</li>
+ * <li>{@link Opcodes#F_APPEND} representing frame with current locals are
+ * the same as the locals in the previous frame, except that additional
+ * locals are defined (<code>nLocal</code> is 1, 2 or 3 and
+ * <code>local</code> elements contains values representing added types).</li>
+ * <li>{@link Opcodes#F_CHOP} representing frame with current locals are the
+ * same as the locals in the previous frame, except that the last 1-3 locals
+ * are absent and with the empty stack (<code>nLocals</code> is 1, 2 or 3).</li>
+ * <li>{@link Opcodes#F_FULL} representing complete frame data.</li></li>
+ * </ul>
+ * </ul> <br>
+ * In both cases the first frame, corresponding to the method's parameters
+ * and access flags, is implicit and must not be visited. Also, it is
+ * illegal to visit two or more frames for the same code location (i.e., at
+ * least one instruction must be visited between two calls to visitFrame).
+ *
+ * @param type
+ * the type of this stack map frame. Must be
+ * {@link Opcodes#F_NEW} for expanded frames, or
+ * {@link Opcodes#F_FULL}, {@link Opcodes#F_APPEND},
+ * {@link Opcodes#F_CHOP}, {@link Opcodes#F_SAME} or
+ * {@link Opcodes#F_APPEND}, {@link Opcodes#F_SAME1} for
+ * compressed frames.
+ * @param nLocal
+ * the number of local variables in the visited frame.
+ * @param local
+ * the local variable types in this frame. This array must not be
+ * modified. Primitive types are represented by
+ * {@link Opcodes#TOP}, {@link Opcodes#INTEGER},
+ * {@link Opcodes#FLOAT}, {@link Opcodes#LONG},
+ * {@link Opcodes#DOUBLE},{@link Opcodes#NULL} or
+ * {@link Opcodes#UNINITIALIZED_THIS} (long and double are
+ * represented by a single element). Reference types are
+ * represented by String objects (representing internal names),
+ * and uninitialized types by Label objects (this label
+ * designates the NEW instruction that created this uninitialized
+ * value).
+ * @param nStack
+ * the number of operand stack elements in the visited frame.
+ * @param stack
+ * the operand stack types in this frame. This array must not be
+ * modified. Its content has the same format as the "local"
+ * array.
+ * @throws IllegalStateException
+ * if a frame is visited just after another one, without any
+ * instruction between the two (unless this frame is a
+ * Opcodes#F_SAME frame, in which case it is silently ignored).
+ */
+ public void visitFrame(int type, int nLocal, Object[] local, int nStack,
+ Object[] stack) {
+ if (mv != null) {
+ mv.visitFrame(type, nLocal, local, nStack, stack);
+ }
+ }
+
+ // -------------------------------------------------------------------------
+ // Normal instructions
+ // -------------------------------------------------------------------------
+
+ /**
+ * Visits a zero operand instruction.
+ *
+ * @param opcode
+ * the opcode of the instruction to be visited. This opcode is
+ * either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1,
+ * ICONST_2, ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1,
+ * FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, IALOAD,
+ * LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD,
+ * IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE,
+ * SASTORE, POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1,
+ * DUP2_X2, SWAP, IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB,
+ * IMUL, LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM,
+ * FREM, DREM, INEG, LNEG, FNEG, DNEG, ISHL, LSHL, ISHR, LSHR,
+ * IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, I2L, I2F, I2D,
+ * L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B, I2C, I2S,
+ * LCMP, FCMPL, FCMPG, DCMPL, DCMPG, IRETURN, LRETURN, FRETURN,
+ * DRETURN, ARETURN, RETURN, ARRAYLENGTH, ATHROW, MONITORENTER,
+ * or MONITOREXIT.
+ */
+ public void visitInsn(int opcode) {
+ if (mv != null) {
+ mv.visitInsn(opcode);
+ }
+ }
+
+ /**
+ * Visits an instruction with a single int operand.
+ *
+ * @param opcode
+ * the opcode of the instruction to be visited. This opcode is
+ * either BIPUSH, SIPUSH or NEWARRAY.
+ * @param operand
+ * the operand of the instruction to be visited.<br>
+ * When opcode is BIPUSH, operand value should be between
+ * Byte.MIN_VALUE and Byte.MAX_VALUE.<br>
+ * When opcode is SIPUSH, operand value should be between
+ * Short.MIN_VALUE and Short.MAX_VALUE.<br>
+ * When opcode is NEWARRAY, operand value should be one of
+ * {@link Opcodes#T_BOOLEAN}, {@link Opcodes#T_CHAR},
+ * {@link Opcodes#T_FLOAT}, {@link Opcodes#T_DOUBLE},
+ * {@link Opcodes#T_BYTE}, {@link Opcodes#T_SHORT},
+ * {@link Opcodes#T_INT} or {@link Opcodes#T_LONG}.
+ */
+ public void visitIntInsn(int opcode, int operand) {
+ if (mv != null) {
+ mv.visitIntInsn(opcode, operand);
+ }
+ }
+
+ /**
+ * Visits a local variable instruction. A local variable instruction is an
+ * instruction that loads or stores the value of a local variable.
+ *
+ * @param opcode
+ * the opcode of the local variable instruction to be visited.
+ * This opcode is either ILOAD, LLOAD, FLOAD, DLOAD, ALOAD,
+ * ISTORE, LSTORE, FSTORE, DSTORE, ASTORE or RET.
+ * @param var
+ * the operand of the instruction to be visited. This operand is
+ * the index of a local variable.
+ */
+ public void visitVarInsn(int opcode, int var) {
+ if (mv != null) {
+ mv.visitVarInsn(opcode, var);
+ }
+ }
+
+ /**
+ * Visits a type instruction. A type instruction is an instruction that
+ * takes the internal name of a class as parameter.
+ *
+ * @param opcode
+ * the opcode of the type instruction to be visited. This opcode
+ * is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.
+ * @param type
+ * the operand of the instruction to be visited. This operand
+ * must be the internal name of an object or array class (see
+ * {@link Type#getInternalName() getInternalName}).
+ */
+ public void visitTypeInsn(int opcode, String type) {
+ if (mv != null) {
+ mv.visitTypeInsn(opcode, type);
+ }
+ }
+
+ /**
+ * Visits a field instruction. A field instruction is an instruction that
+ * loads or stores the value of a field of an object.
+ *
+ * @param opcode
+ * the opcode of the type instruction to be visited. This opcode
+ * is either GETSTATIC, PUTSTATIC, GETFIELD or PUTFIELD.
+ * @param owner
+ * the internal name of the field's owner class (see
+ * {@link Type#getInternalName() getInternalName}).
+ * @param name
+ * the field's name.
+ * @param desc
+ * the field's descriptor (see {@link Type Type}).
+ */
+ public void visitFieldInsn(int opcode, String owner, String name,
+ String desc) {
+ if (mv != null) {
+ mv.visitFieldInsn(opcode, owner, name, desc);
+ }
+ }
+
+ /**
+ * Visits a method instruction. A method instruction is an instruction that
+ * invokes a method.
+ *
+ * @param opcode
+ * the opcode of the type instruction to be visited. This opcode
+ * is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or
+ * INVOKEINTERFACE.
+ * @param owner
+ * the internal name of the method's owner class (see
+ * {@link Type#getInternalName() getInternalName}).
+ * @param name
+ * the method's name.
+ * @param desc
+ * the method's descriptor (see {@link Type Type}).
+ */
+ public void visitMethodInsn(int opcode, String owner, String name,
+ String desc) {
+ if (mv != null) {
+ mv.visitMethodInsn(opcode, owner, name, desc);
+ }
+ }
+
+ /**
+ * Visits an invokedynamic instruction.
+ *
+ * @param name
+ * the method's name.
+ * @param desc
+ * the method's descriptor (see {@link Type Type}).
+ * @param bsm
+ * the bootstrap method.
+ * @param bsmArgs
+ * the bootstrap method constant arguments. Each argument must be
+ * an {@link Integer}, {@link Float}, {@link Long},
+ * {@link Double}, {@link String}, {@link Type} or {@link Handle}
+ * value. This method is allowed to modify the content of the
+ * array so a caller should expect that this array may change.
+ */
+ public void visitInvokeDynamicInsn(String name, String desc, Handle bsm,
+ Object... bsmArgs) {
+ if (mv != null) {
+ mv.visitInvokeDynamicInsn(name, desc, bsm, bsmArgs);
+ }
+ }
+
+ /**
+ * Visits a jump instruction. A jump instruction is an instruction that may
+ * jump to another instruction.
+ *
+ * @param opcode
+ * the opcode of the type instruction to be visited. This opcode
+ * is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ,
+ * IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE,
+ * IF_ACMPEQ, IF_ACMPNE, GOTO, JSR, IFNULL or IFNONNULL.
+ * @param label
+ * the operand of the instruction to be visited. This operand is
+ * a label that designates the instruction to which the jump
+ * instruction may jump.
+ */
+ public void visitJumpInsn(int opcode, Label label) {
+ if (mv != null) {
+ mv.visitJumpInsn(opcode, label);
+ }
+ }
+
+ /**
+ * Visits a label. A label designates the instruction that will be visited
+ * just after it.
+ *
+ * @param label
+ * a {@link Label Label} object.
+ */
+ public void visitLabel(Label label) {
+ if (mv != null) {
+ mv.visitLabel(label);
+ }
+ }
+
+ // -------------------------------------------------------------------------
+ // Special instructions
+ // -------------------------------------------------------------------------
+
+ /**
+ * Visits a LDC instruction. Note that new constant types may be added in
+ * future versions of the Java Virtual Machine. To easily detect new
+ * constant types, implementations of this method should check for
+ * unexpected constant types, like this:
+ *
+ * <pre>
+ * if (cst instanceof Integer) {
+ * // ...
+ * } else if (cst instanceof Float) {
+ * // ...
+ * } else if (cst instanceof Long) {
+ * // ...
+ * } else if (cst instanceof Double) {
+ * // ...
+ * } else if (cst instanceof String) {
+ * // ...
+ * } else if (cst instanceof Type) {
+ * int sort = ((Type) cst).getSort();
+ * if (sort == Type.OBJECT) {
+ * // ...
+ * } else if (sort == Type.ARRAY) {
+ * // ...
+ * } else if (sort == Type.METHOD) {
+ * // ...
+ * } else {
+ * // throw an exception
+ * }
+ * } else if (cst instanceof Handle) {
+ * // ...
+ * } else {
+ * // throw an exception
+ * }
+ * </pre>
+ *
+ * @param cst
+ * the constant to be loaded on the stack. This parameter must be
+ * a non null {@link Integer}, a {@link Float}, a {@link Long}, a
+ * {@link Double}, a {@link String}, a {@link Type} of OBJECT or
+ * ARRAY sort for <tt>.class</tt> constants, for classes whose
+ * version is 49.0, a {@link Type} of METHOD sort or a
+ * {@link Handle} for MethodType and MethodHandle constants, for
+ * classes whose version is 51.0.
+ */
+ public void visitLdcInsn(Object cst) {
+ if (mv != null) {
+ mv.visitLdcInsn(cst);
+ }
+ }
+
+ /**
+ * Visits an IINC instruction.
+ *
+ * @param var
+ * index of the local variable to be incremented.
+ * @param increment
+ * amount to increment the local variable by.
+ */
+ public void visitIincInsn(int var, int increment) {
+ if (mv != null) {
+ mv.visitIincInsn(var, increment);
+ }
+ }
+
+ /**
+ * Visits a TABLESWITCH instruction.
+ *
+ * @param min
+ * the minimum key value.
+ * @param max
+ * the maximum key value.
+ * @param dflt
+ * beginning of the default handler block.
+ * @param labels
+ * beginnings of the handler blocks. <tt>labels[i]</tt> is the
+ * beginning of the handler block for the <tt>min + i</tt> key.
+ */
+ public void visitTableSwitchInsn(int min, int max, Label dflt,
+ Label... labels) {
+ if (mv != null) {
+ mv.visitTableSwitchInsn(min, max, dflt, labels);
+ }
+ }
+
+ /**
+ * Visits a LOOKUPSWITCH instruction.
+ *
+ * @param dflt
+ * beginning of the default handler block.
+ * @param keys
+ * the values of the keys.
+ * @param labels
+ * beginnings of the handler blocks. <tt>labels[i]</tt> is the
+ * beginning of the handler block for the <tt>keys[i]</tt> key.
+ */
+ public void visitLookupSwitchInsn(Label dflt, int[] keys, Label[] labels) {
+ if (mv != null) {
+ mv.visitLookupSwitchInsn(dflt, keys, labels);
+ }
+ }
+
+ /**
+ * Visits a MULTIANEWARRAY instruction.
+ *
+ * @param desc
+ * an array type descriptor (see {@link Type Type}).
+ * @param dims
+ * number of dimensions of the array to allocate.
+ */
+ public void visitMultiANewArrayInsn(String desc, int dims) {
+ if (mv != null) {
+ mv.visitMultiANewArrayInsn(desc, dims);
+ }
+ }
+
+ // -------------------------------------------------------------------------
+ // Exceptions table entries, debug information, max stack and max locals
+ // -------------------------------------------------------------------------
+
+ /**
+ * Visits a try catch block.
+ *
+ * @param start
+ * beginning of the exception handler's scope (inclusive).
+ * @param end
+ * end of the exception handler's scope (exclusive).
+ * @param handler
+ * beginning of the exception handler's code.
+ * @param type
+ * internal name of the type of exceptions handled by the
+ * handler, or <tt>null</tt> to catch any exceptions (for
+ * "finally" blocks).
+ * @throws IllegalArgumentException
+ * if one of the labels has already been visited by this visitor
+ * (by the {@link #visitLabel visitLabel} method).
+ */
+ public void visitTryCatchBlock(Label start, Label end, Label handler,
+ String type) {
+ if (mv != null) {
+ mv.visitTryCatchBlock(start, end, handler, type);
+ }
+ }
+
+ /**
+ * Visits a local variable declaration.
+ *
+ * @param name
+ * the name of a local variable.
+ * @param desc
+ * the type descriptor of this local variable.
+ * @param signature
+ * the type signature of this local variable. May be
+ * <tt>null</tt> if the local variable type does not use generic
+ * types.
+ * @param start
+ * the first instruction corresponding to the scope of this local
+ * variable (inclusive).
+ * @param end
+ * the last instruction corresponding to the scope of this local
+ * variable (exclusive).
+ * @param index
+ * the local variable's index.
+ * @throws IllegalArgumentException
+ * if one of the labels has not already been visited by this
+ * visitor (by the {@link #visitLabel visitLabel} method).
+ */
+ public void visitLocalVariable(String name, String desc, String signature,
+ Label start, Label end, int index) {
+ if (mv != null) {
+ mv.visitLocalVariable(name, desc, signature, start, end, index);
+ }
+ }
+
+ /**
+ * Visits a line number declaration.
+ *
+ * @param line
+ * a line number. This number refers to the source file from
+ * which the class was compiled.
+ * @param start
+ * the first instruction corresponding to this line number.
+ * @throws IllegalArgumentException
+ * if <tt>start</tt> has not already been visited by this
+ * visitor (by the {@link #visitLabel visitLabel} method).
+ */
+ public void visitLineNumber(int line, Label start) {
+ if (mv != null) {
+ mv.visitLineNumber(line, start);
+ }
+ }
+
+ /**
+ * Visits the maximum stack size and the maximum number of local variables
+ * of the method.
+ *
+ * @param maxStack
+ * maximum stack size of the method.
+ * @param maxLocals
+ * maximum number of local variables for the method.
+ */
+ public void visitMaxs(int maxStack, int maxLocals) {
+ if (mv != null) {
+ mv.visitMaxs(maxStack, maxLocals);
+ }
+ }
+
+ /**
+ * Visits the end of the method. This method, which is the last one to be
+ * called, is used to inform the visitor that all the annotations and
+ * attributes of the method have been visited.
+ */
+ public void visitEnd() {
+ if (mv != null) {
+ mv.visitEnd();
+ }
+ }
+}