com.sleepycat.asm.MethodWriter Maven / Gradle / Ivy
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/***
* ASM: a very small and fast Java bytecode manipulation framework
* Copyright (c) 2000-2005 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 com.sleepycat.asm;
/**
* A {@link MethodVisitor} that generates methods in bytecode form. Each visit
* method of this class appends the bytecode corresponding to the visited
* instruction to a byte vector, in the order these methods are called.
*
* @author Eric Bruneton
*/
class MethodWriter implements MethodVisitor {
/**
* Next method writer (see {@link ClassWriter#firstMethod firstMethod}).
*/
MethodWriter next;
/**
* The class writer to which this method must be added.
*/
ClassWriter cw;
/**
* Access flags of this method.
*/
private int access;
/**
* The index of the constant pool item that contains the name of this
* method.
*/
private int name;
/**
* The index of the constant pool item that contains the descriptor of this
* method.
*/
private int desc;
/**
* The descriptor of this method.
*/
private String descriptor;
/**
* If not zero, indicates that the code of this method must be copied from
* the ClassReader associated to this writer in cw.cr. More
* precisely, this field gives the index of the first byte to copied from
* cw.cr.b.
*/
int classReaderOffset;
/**
* If not zero, indicates that the code of this method must be copied from
* the ClassReader associated to this writer in cw.cr. More
* precisely, this field gives the number of bytes to copied from
* cw.cr.b.
*/
int classReaderLength;
/**
* The signature of this method.
*/
String signature;
/**
* Number of exceptions that can be thrown by this method.
*/
int exceptionCount;
/**
* The exceptions that can be thrown by this method. More precisely, this
* array contains the indexes of the constant pool items that contain the
* internal names of these exception classes.
*/
int[] exceptions;
/**
* The annotation default attribute of this method. May be null.
*/
private ByteVector annd;
/**
* The runtime visible annotations of this method. May be null.
*/
private AnnotationWriter anns;
/**
* The runtime invisible annotations of this method. May be null.
*/
private AnnotationWriter ianns;
/**
* The runtime visible parameter annotations of this method. May be
* null.
*/
private AnnotationWriter[] panns;
/**
* The runtime invisible parameter annotations of this method. May be
* null.
*/
private AnnotationWriter[] ipanns;
/**
* The non standard attributes of the method.
*/
private Attribute attrs;
/**
* The bytecode of this method.
*/
private ByteVector code = new ByteVector();
/**
* Maximum stack size of this method.
*/
private int maxStack;
/**
* Maximum number of local variables for this method.
*/
private int maxLocals;
/**
* Number of entries in the catch table of this method.
*/
private int catchCount;
/**
* The catch table of this method.
*/
private Handler catchTable;
/**
* The last element in the catchTable handler list.
*/
private Handler lastHandler;
/**
* Number of entries in the LocalVariableTable attribute.
*/
private int localVarCount;
/**
* The LocalVariableTable attribute.
*/
private ByteVector localVar;
/**
* Number of entries in the LocalVariableTypeTable attribute.
*/
private int localVarTypeCount;
/**
* The LocalVariableTypeTable attribute.
*/
private ByteVector localVarType;
/**
* Number of entries in the LineNumberTable attribute.
*/
private int lineNumberCount;
/**
* The LineNumberTable attribute.
*/
private ByteVector lineNumber;
/**
* The non standard attributes of the method's code.
*/
private Attribute cattrs;
/**
* Indicates if some jump instructions are too small and need to be resized.
*/
private boolean resize;
/*
* Fields for the control flow graph analysis algorithm (used to compute the
* maximum stack size). 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.
*/
/**
* true if the maximum stack size and number of local variables
* must be automatically computed.
*/
private final boolean computeMaxs;
/**
* The (relative) stack size after the last visited instruction. This size
* is relative to the beginning of the current basic block, i.e., the true
* stack size after the last visited instruction is equal to the {@link
* Label#beginStackSize beginStackSize} of the current basic block plus
* stackSize.
*/
private int stackSize;
/**
* The (relative) maximum stack size after the last visited instruction.
* This size is relative to the beginning of the current basic block, i.e.,
* the true maximum stack size after the last visited instruction is equal
* to the {@link Label#beginStackSize beginStackSize} of the current basic
* block plus stackSize.
*/
private int maxStackSize;
/**
* The current basic block. This block is the basic block to which the next
* instruction to be visited must be added.
*/
private Label currentBlock;
/**
* The basic block stack used by the control flow analysis algorithm. This
* stack is represented by a linked list of {@link Label Label} objects,
* linked to each other by their {@link Label#next} field. This stack must
* not be confused with the JVM stack used to execute the JVM instructions!
*/
private Label blockStack;
/**
* The stack size variation corresponding to each JVM instruction. This
* stack variation is equal to the size of the values produced by an
* instruction, minus the size of the values consumed by this instruction.
*/
private final static int[] SIZE;
// ------------------------------------------------------------------------
// Static initializer
// ------------------------------------------------------------------------
/**
* Computes the stack size variation corresponding to each JVM instruction.
*/
static {
int i;
int[] b = new int[202];
String s = "EFFFFFFFFGGFFFGGFFFEEFGFGFEEEEEEEEEEEEEEEEEEEEDEDEDDDDD"
+ "CDCDEEEEEEEEEEEEEEEEEEEEBABABBBBDCFFFGGGEDCDCDCDCDCDCDCDCD"
+ "CDCEEEEDDDDDDDCDCDCEFEFDDEEFFDEDEEEBDDBBDDDDDDCCCCCCCCEFED"
+ "DDCDCDEEEEEEEEEEFEEEEEEDDEEDDEE";
for (i = 0; i < b.length; ++i) {
b[i] = s.charAt(i) - 'E';
}
SIZE = b;
// code to generate the above string
//
// int NA = 0; // not applicable (unused opcode or variable size opcode)
//
// b = new int[] {
// 0, //NOP, // visitInsn
// 1, //ACONST_NULL, // -
// 1, //ICONST_M1, // -
// 1, //ICONST_0, // -
// 1, //ICONST_1, // -
// 1, //ICONST_2, // -
// 1, //ICONST_3, // -
// 1, //ICONST_4, // -
// 1, //ICONST_5, // -
// 2, //LCONST_0, // -
// 2, //LCONST_1, // -
// 1, //FCONST_0, // -
// 1, //FCONST_1, // -
// 1, //FCONST_2, // -
// 2, //DCONST_0, // -
// 2, //DCONST_1, // -
// 1, //BIPUSH, // visitIntInsn
// 1, //SIPUSH, // -
// 1, //LDC, // visitLdcInsn
// NA, //LDC_W, // -
// NA, //LDC2_W, // -
// 1, //ILOAD, // visitVarInsn
// 2, //LLOAD, // -
// 1, //FLOAD, // -
// 2, //DLOAD, // -
// 1, //ALOAD, // -
// NA, //ILOAD_0, // -
// NA, //ILOAD_1, // -
// NA, //ILOAD_2, // -
// NA, //ILOAD_3, // -
// NA, //LLOAD_0, // -
// NA, //LLOAD_1, // -
// NA, //LLOAD_2, // -
// NA, //LLOAD_3, // -
// NA, //FLOAD_0, // -
// NA, //FLOAD_1, // -
// NA, //FLOAD_2, // -
// NA, //FLOAD_3, // -
// NA, //DLOAD_0, // -
// NA, //DLOAD_1, // -
// NA, //DLOAD_2, // -
// NA, //DLOAD_3, // -
// NA, //ALOAD_0, // -
// NA, //ALOAD_1, // -
// NA, //ALOAD_2, // -
// NA, //ALOAD_3, // -
// -1, //IALOAD, // visitInsn
// 0, //LALOAD, // -
// -1, //FALOAD, // -
// 0, //DALOAD, // -
// -1, //AALOAD, // -
// -1, //BALOAD, // -
// -1, //CALOAD, // -
// -1, //SALOAD, // -
// -1, //ISTORE, // visitVarInsn
// -2, //LSTORE, // -
// -1, //FSTORE, // -
// -2, //DSTORE, // -
// -1, //ASTORE, // -
// NA, //ISTORE_0, // -
// NA, //ISTORE_1, // -
// NA, //ISTORE_2, // -
// NA, //ISTORE_3, // -
// NA, //LSTORE_0, // -
// NA, //LSTORE_1, // -
// NA, //LSTORE_2, // -
// NA, //LSTORE_3, // -
// NA, //FSTORE_0, // -
// NA, //FSTORE_1, // -
// NA, //FSTORE_2, // -
// NA, //FSTORE_3, // -
// NA, //DSTORE_0, // -
// NA, //DSTORE_1, // -
// NA, //DSTORE_2, // -
// NA, //DSTORE_3, // -
// NA, //ASTORE_0, // -
// NA, //ASTORE_1, // -
// NA, //ASTORE_2, // -
// NA, //ASTORE_3, // -
// -3, //IASTORE, // visitInsn
// -4, //LASTORE, // -
// -3, //FASTORE, // -
// -4, //DASTORE, // -
// -3, //AASTORE, // -
// -3, //BASTORE, // -
// -3, //CASTORE, // -
// -3, //SASTORE, // -
// -1, //POP, // -
// -2, //POP2, // -
// 1, //DUP, // -
// 1, //DUP_X1, // -
// 1, //DUP_X2, // -
// 2, //DUP2, // -
// 2, //DUP2_X1, // -
// 2, //DUP2_X2, // -
// 0, //SWAP, // -
// -1, //IADD, // -
// -2, //LADD, // -
// -1, //FADD, // -
// -2, //DADD, // -
// -1, //ISUB, // -
// -2, //LSUB, // -
// -1, //FSUB, // -
// -2, //DSUB, // -
// -1, //IMUL, // -
// -2, //LMUL, // -
// -1, //FMUL, // -
// -2, //DMUL, // -
// -1, //IDIV, // -
// -2, //LDIV, // -
// -1, //FDIV, // -
// -2, //DDIV, // -
// -1, //IREM, // -
// -2, //LREM, // -
// -1, //FREM, // -
// -2, //DREM, // -
// 0, //INEG, // -
// 0, //LNEG, // -
// 0, //FNEG, // -
// 0, //DNEG, // -
// -1, //ISHL, // -
// -1, //LSHL, // -
// -1, //ISHR, // -
// -1, //LSHR, // -
// -1, //IUSHR, // -
// -1, //LUSHR, // -
// -1, //IAND, // -
// -2, //LAND, // -
// -1, //IOR, // -
// -2, //LOR, // -
// -1, //IXOR, // -
// -2, //LXOR, // -
// 0, //IINC, // visitIincInsn
// 1, //I2L, // visitInsn
// 0, //I2F, // -
// 1, //I2D, // -
// -1, //L2I, // -
// -1, //L2F, // -
// 0, //L2D, // -
// 0, //F2I, // -
// 1, //F2L, // -
// 1, //F2D, // -
// -1, //D2I, // -
// 0, //D2L, // -
// -1, //D2F, // -
// 0, //I2B, // -
// 0, //I2C, // -
// 0, //I2S, // -
// -3, //LCMP, // -
// -1, //FCMPL, // -
// -1, //FCMPG, // -
// -3, //DCMPL, // -
// -3, //DCMPG, // -
// -1, //IFEQ, // visitJumpInsn
// -1, //IFNE, // -
// -1, //IFLT, // -
// -1, //IFGE, // -
// -1, //IFGT, // -
// -1, //IFLE, // -
// -2, //IF_ICMPEQ, // -
// -2, //IF_ICMPNE, // -
// -2, //IF_ICMPLT, // -
// -2, //IF_ICMPGE, // -
// -2, //IF_ICMPGT, // -
// -2, //IF_ICMPLE, // -
// -2, //IF_ACMPEQ, // -
// -2, //IF_ACMPNE, // -
// 0, //GOTO, // -
// 1, //JSR, // -
// 0, //RET, // visitVarInsn
// -1, //TABLESWITCH, // visiTableSwitchInsn
// -1, //LOOKUPSWITCH, // visitLookupSwitch
// -1, //IRETURN, // visitInsn
// -2, //LRETURN, // -
// -1, //FRETURN, // -
// -2, //DRETURN, // -
// -1, //ARETURN, // -
// 0, //RETURN, // -
// NA, //GETSTATIC, // visitFieldInsn
// NA, //PUTSTATIC, // -
// NA, //GETFIELD, // -
// NA, //PUTFIELD, // -
// NA, //INVOKEVIRTUAL, // visitMethodInsn
// NA, //INVOKESPECIAL, // -
// NA, //INVOKESTATIC, // -
// NA, //INVOKEINTERFACE, // -
// NA, //UNUSED, // NOT VISITED
// 1, //NEW, // visitTypeInsn
// 0, //NEWARRAY, // visitIntInsn
// 0, //ANEWARRAY, // visitTypeInsn
// 0, //ARRAYLENGTH, // visitInsn
// NA, //ATHROW, // -
// 0, //CHECKCAST, // visitTypeInsn
// 0, //INSTANCEOF, // -
// -1, //MONITORENTER, // visitInsn
// -1, //MONITOREXIT, // -
// NA, //WIDE, // NOT VISITED
// NA, //MULTIANEWARRAY, // visitMultiANewArrayInsn
// -1, //IFNULL, // visitJumpInsn
// -1, //IFNONNULL, // -
// NA, //GOTO_W, // -
// NA, //JSR_W, // -
// };
// for (i = 0; i < b.length; ++i) {
// System.err.print((char)('E' + b[i]));
// }
// System.err.println();
}
// ------------------------------------------------------------------------
// Constructor
// ------------------------------------------------------------------------
/**
* Constructs a new {@link MethodWriter}.
*
* @param cw the class writer in which the method must be added.
* @param access the method's access flags (see {@link Opcodes}).
* @param name the method's name.
* @param desc the method's descriptor (see {@link Type}).
* @param signature the method's signature. May be null.
* @param exceptions the internal names of the method's exceptions. May be
* null.
* @param computeMaxs true if the maximum stack size and number
* of local variables must be automatically computed.
*/
MethodWriter(
final ClassWriter cw,
final int access,
final String name,
final String desc,
final String signature,
final String[] exceptions,
final boolean computeMaxs)
{
if (cw.firstMethod == null) {
cw.firstMethod = this;
} else {
cw.lastMethod.next = this;
}
cw.lastMethod = this;
this.cw = cw;
this.access = access;
this.name = cw.newUTF8(name);
this.desc = cw.newUTF8(desc);
this.descriptor = desc;
this.signature = signature;
if (exceptions != null && exceptions.length > 0) {
exceptionCount = exceptions.length;
this.exceptions = new int[exceptionCount];
for (int i = 0; i < exceptionCount; ++i) {
this.exceptions[i] = cw.newClass(exceptions[i]);
}
}
this.computeMaxs = computeMaxs;
if (computeMaxs) {
// updates maxLocals
int size = getArgumentsAndReturnSizes(desc) >> 2;
if ((access & Opcodes.ACC_STATIC) != 0) {
--size;
}
maxLocals = size;
// pushes the first block onto the stack of blocks to be visited
currentBlock = new Label();
currentBlock.pushed = true;
blockStack = currentBlock;
}
}
// ------------------------------------------------------------------------
// Implementation of the MethodVisitor interface
// ------------------------------------------------------------------------
public AnnotationVisitor visitAnnotationDefault() {
annd = new ByteVector();
return new AnnotationWriter(cw, false, annd, null, 0);
}
public AnnotationVisitor visitAnnotation(
final String desc,
final boolean visible)
{
ByteVector bv = new ByteVector();
// write type, and reserve space for values count
bv.putShort(cw.newUTF8(desc)).putShort(0);
AnnotationWriter aw = new AnnotationWriter(cw, true, bv, bv, 2);
if (visible) {
aw.next = anns;
anns = aw;
} else {
aw.next = ianns;
ianns = aw;
}
return aw;
}
public AnnotationVisitor visitParameterAnnotation(
final int parameter,
final String desc,
final boolean visible)
{
ByteVector bv = new ByteVector();
// write type, and reserve space for values count
bv.putShort(cw.newUTF8(desc)).putShort(0);
AnnotationWriter aw = new AnnotationWriter(cw, true, bv, bv, 2);
if (visible) {
if (panns == null) {
panns = new AnnotationWriter[Type.getArgumentTypes(descriptor).length];
}
aw.next = panns[parameter];
panns[parameter] = aw;
} else {
if (ipanns == null) {
ipanns = new AnnotationWriter[Type.getArgumentTypes(descriptor).length];
}
aw.next = ipanns[parameter];
ipanns[parameter] = aw;
}
return aw;
}
public void visitAttribute(final Attribute attr) {
if (attr.isCodeAttribute()) {
attr.next = cattrs;
cattrs = attr;
} else {
attr.next = attrs;
attrs = attr;
}
}
public void visitCode() {
}
public void visitInsn(final int opcode) {
if (computeMaxs) {
// updates current and max stack sizes
int size = stackSize + SIZE[opcode];
if (size > maxStackSize) {
maxStackSize = size;
}
stackSize = size;
// if opcode == ATHROW or xRETURN, ends current block (no successor)
if ((opcode >= Opcodes.IRETURN && opcode <= Opcodes.RETURN)
|| opcode == Opcodes.ATHROW)
{
if (currentBlock != null) {
currentBlock.maxStackSize = maxStackSize;
currentBlock = null;
}
}
}
// adds the instruction to the bytecode of the method
code.putByte(opcode);
}
public void visitIntInsn(final int opcode, final int operand) {
if (computeMaxs && opcode != Opcodes.NEWARRAY) {
// updates current and max stack sizes only if opcode == NEWARRAY
// (stack size variation = 0 for BIPUSH or SIPUSH)
int size = stackSize + 1;
if (size > maxStackSize) {
maxStackSize = size;
}
stackSize = size;
}
// adds the instruction to the bytecode of the method
if (opcode == Opcodes.SIPUSH) {
code.put12(opcode, operand);
} else { // BIPUSH or NEWARRAY
code.put11(opcode, operand);
}
}
public void visitVarInsn(final int opcode, final int var) {
if (computeMaxs) {
// updates current and max stack sizes
if (opcode == Opcodes.RET) {
// no stack change, but end of current block (no successor)
if (currentBlock != null) {
currentBlock.maxStackSize = maxStackSize;
currentBlock = null;
}
} else { // xLOAD or xSTORE
int size = stackSize + SIZE[opcode];
if (size > maxStackSize) {
maxStackSize = size;
}
stackSize = size;
}
// updates max locals
int n;
if (opcode == Opcodes.LLOAD || opcode == Opcodes.DLOAD
|| opcode == Opcodes.LSTORE || opcode == Opcodes.DSTORE)
{
n = var + 2;
} else {
n = var + 1;
}
if (n > maxLocals) {
maxLocals = n;
}
}
// adds the instruction to the bytecode of the method
if (var < 4 && opcode != Opcodes.RET) {
int opt;
if (opcode < Opcodes.ISTORE) {
/* ILOAD_0 */
opt = 26 + ((opcode - Opcodes.ILOAD) << 2) + var;
} else {
/* ISTORE_0 */
opt = 59 + ((opcode - Opcodes.ISTORE) << 2) + var;
}
code.putByte(opt);
} else if (var >= 256) {
code.putByte(196 /* WIDE */).put12(opcode, var);
} else {
code.put11(opcode, var);
}
}
public void visitTypeInsn(final int opcode, final String desc) {
if (computeMaxs && opcode == Opcodes.NEW) {
// updates current and max stack sizes only if opcode == NEW
// (stack size variation = 0 for ANEWARRAY, CHECKCAST, INSTANCEOF)
int size = stackSize + 1;
if (size > maxStackSize) {
maxStackSize = size;
}
stackSize = size;
}
// adds the instruction to the bytecode of the method
code.put12(opcode, cw.newClass(desc));
}
public void visitFieldInsn(
final int opcode,
final String owner,
final String name,
final String desc)
{
if (computeMaxs) {
int size;
// computes the stack size variation
char c = desc.charAt(0);
switch (opcode) {
case Opcodes.GETSTATIC:
size = stackSize + (c == 'D' || c == 'J' ? 2 : 1);
break;
case Opcodes.PUTSTATIC:
size = stackSize + (c == 'D' || c == 'J' ? -2 : -1);
break;
case Opcodes.GETFIELD:
size = stackSize + (c == 'D' || c == 'J' ? 1 : 0);
break;
// case Constants.PUTFIELD:
default:
size = stackSize + (c == 'D' || c == 'J' ? -3 : -2);
break;
}
// updates current and max stack sizes
if (size > maxStackSize) {
maxStackSize = size;
}
stackSize = size;
}
// adds the instruction to the bytecode of the method
code.put12(opcode, cw.newField(owner, name, desc));
}
public void visitMethodInsn(
final int opcode,
final String owner,
final String name,
final String desc)
{
boolean itf = opcode == Opcodes.INVOKEINTERFACE;
Item i = cw.newMethodItem(owner, name, desc, itf);
int argSize = i.intVal;
if (computeMaxs) {
/*
* computes the stack size variation. In order not to recompute
* several times this variation for the same Item, we use the intVal
* field of this item to store this variation, once it has been
* computed. More precisely this intVal field stores the sizes of
* the arguments and of the return value corresponding to desc.
*/
if (argSize == 0) {
// the above sizes have not been computed yet, so we compute
// them...
argSize = getArgumentsAndReturnSizes(desc);
// ... and we save them in order not to recompute them in the
// future
i.intVal = argSize;
}
int size;
if (opcode == Opcodes.INVOKESTATIC) {
size = stackSize - (argSize >> 2) + (argSize & 0x03) + 1;
} else {
size = stackSize - (argSize >> 2) + (argSize & 0x03);
}
// updates current and max stack sizes
if (size > maxStackSize) {
maxStackSize = size;
}
stackSize = size;
}
// adds the instruction to the bytecode of the method
if (itf) {
if (!computeMaxs) {
if (argSize == 0) {
argSize = getArgumentsAndReturnSizes(desc);
i.intVal = argSize;
}
}
code.put12(Opcodes.INVOKEINTERFACE, i.index).put11(argSize >> 2, 0);
} else {
code.put12(opcode, i.index);
}
}
public void visitJumpInsn(final int opcode, final Label label) {
if (computeMaxs) {
if (opcode == Opcodes.GOTO) {
// no stack change, but end of current block (with one new
// successor)
if (currentBlock != null) {
currentBlock.maxStackSize = maxStackSize;
addSuccessor(stackSize, label);
currentBlock = null;
}
} else if (opcode == Opcodes.JSR) {
if (currentBlock != null) {
addSuccessor(stackSize + 1, label);
}
} else {
// updates current stack size (max stack size unchanged because
// stack size variation always negative in this case)
stackSize += SIZE[opcode];
if (currentBlock != null) {
addSuccessor(stackSize, label);
}
}
}
// adds the instruction to the bytecode of the method
if (label.resolved && label.position - code.length < Short.MIN_VALUE) {
/*
* case of a backward jump with an offset < -32768. In this case we
* automatically replace GOTO with GOTO_W, JSR with JSR_W and IFxxx
* with IFNOTxxx GOTO_W , where IFNOTxxx is the
* "opposite" opcode of IFxxx (i.e., IFNE for IFEQ) and where
* designates the instruction just after the GOTO_W.
*/
if (opcode == Opcodes.GOTO) {
code.putByte(200); // GOTO_W
} else if (opcode == Opcodes.JSR) {
code.putByte(201); // JSR_W
} else {
code.putByte(opcode <= 166
? ((opcode + 1) ^ 1) - 1
: opcode ^ 1);
code.putShort(8); // jump offset
code.putByte(200); // GOTO_W
}
label.put(this, code, code.length - 1, true);
} else {
/*
* case of a backward jump with an offset >= -32768, or of a forward
* jump with, of course, an unknown offset. In these cases we store
* the offset in 2 bytes (which will be increased in
* resizeInstructions, if needed).
*/
code.putByte(opcode);
label.put(this, code, code.length - 1, false);
}
}
public void visitLabel(final Label label) {
if (computeMaxs) {
if (currentBlock != null) {
// ends current block (with one new successor)
currentBlock.maxStackSize = maxStackSize;
addSuccessor(stackSize, label);
}
// begins a new current block,
// resets the relative current and max stack sizes
currentBlock = label;
stackSize = 0;
maxStackSize = 0;
}
// resolves previous forward references to label, if any
resize |= label.resolve(this, code.length, code.data);
}
public void visitLdcInsn(final Object cst) {
Item i = cw.newConstItem(cst);
if (computeMaxs) {
int size;
// computes the stack size variation
if (i.type == ClassWriter.LONG || i.type == ClassWriter.DOUBLE) {
size = stackSize + 2;
} else {
size = stackSize + 1;
}
// updates current and max stack sizes
if (size > maxStackSize) {
maxStackSize = size;
}
stackSize = size;
}
// adds the instruction to the bytecode of the method
int index = i.index;
if (i.type == ClassWriter.LONG || i.type == ClassWriter.DOUBLE) {
code.put12(20 /* LDC2_W */, index);
} else if (index >= 256) {
code.put12(19 /* LDC_W */, index);
} else {
code.put11(Opcodes.LDC, index);
}
}
public void visitIincInsn(final int var, final int increment) {
if (computeMaxs) {
// updates max locals only (no stack change)
int n = var + 1;
if (n > maxLocals) {
maxLocals = n;
}
}
// adds the instruction to the bytecode of the method
if ((var > 255) || (increment > 127) || (increment < -128)) {
code.putByte(196 /* WIDE */)
.put12(Opcodes.IINC, var)
.putShort(increment);
} else {
code.putByte(Opcodes.IINC).put11(var, increment);
}
}
public void visitTableSwitchInsn(
final int min,
final int max,
final Label dflt,
final Label labels[])
{
if (computeMaxs) {
// updates current stack size (max stack size unchanged)
--stackSize;
// ends current block (with many new successors)
if (currentBlock != null) {
currentBlock.maxStackSize = maxStackSize;
addSuccessor(stackSize, dflt);
for (int i = 0; i < labels.length; ++i) {
addSuccessor(stackSize, labels[i]);
}
currentBlock = null;
}
}
// adds the instruction to the bytecode of the method
int source = code.length;
code.putByte(Opcodes.TABLESWITCH);
while (code.length % 4 != 0) {
code.putByte(0);
}
dflt.put(this, code, source, true);
code.putInt(min).putInt(max);
for (int i = 0; i < labels.length; ++i) {
labels[i].put(this, code, source, true);
}
}
public void visitLookupSwitchInsn(
final Label dflt,
final int keys[],
final Label labels[])
{
if (computeMaxs) {
// updates current stack size (max stack size unchanged)
--stackSize;
// ends current block (with many new successors)
if (currentBlock != null) {
currentBlock.maxStackSize = maxStackSize;
addSuccessor(stackSize, dflt);
for (int i = 0; i < labels.length; ++i) {
addSuccessor(stackSize, labels[i]);
}
currentBlock = null;
}
}
// adds the instruction to the bytecode of the method
int source = code.length;
code.putByte(Opcodes.LOOKUPSWITCH);
while (code.length % 4 != 0) {
code.putByte(0);
}
dflt.put(this, code, source, true);
code.putInt(labels.length);
for (int i = 0; i < labels.length; ++i) {
code.putInt(keys[i]);
labels[i].put(this, code, source, true);
}
}
public void visitMultiANewArrayInsn(final String desc, final int dims) {
if (computeMaxs) {
// updates current stack size (max stack size unchanged because
// stack size variation always negative or null)
stackSize += 1 - dims;
}
// adds the instruction to the bytecode of the method
code.put12(Opcodes.MULTIANEWARRAY, cw.newClass(desc)).putByte(dims);
}
public void visitTryCatchBlock(
final Label start,
final Label end,
final Label handler,
final String type)
{
if (computeMaxs) {
// pushes handler block onto the stack of blocks to be visited
if (!handler.pushed) {
handler.beginStackSize = 1;
handler.pushed = true;
handler.next = blockStack;
blockStack = handler;
}
}
++catchCount;
Handler h = new Handler();
h.start = start;
h.end = end;
h.handler = handler;
h.desc = type;
h.type = type != null ? cw.newClass(type) : 0;
if (lastHandler == null) {
catchTable = h;
} else {
lastHandler.next = h;
}
lastHandler = h;
}
public void visitLocalVariable(
final String name,
final String desc,
final String signature,
final Label start,
final Label end,
final int index)
{
if (signature != null) {
if (localVarType == null) {
localVarType = new ByteVector();
}
++localVarTypeCount;
localVarType.putShort(start.position)
.putShort(end.position - start.position)
.putShort(cw.newUTF8(name))
.putShort(cw.newUTF8(signature))
.putShort(index);
}
if (localVar == null) {
localVar = new ByteVector();
}
++localVarCount;
localVar.putShort(start.position)
.putShort(end.position - start.position)
.putShort(cw.newUTF8(name))
.putShort(cw.newUTF8(desc))
.putShort(index);
}
public void visitLineNumber(final int line, final Label start) {
if (lineNumber == null) {
lineNumber = new ByteVector();
}
++lineNumberCount;
lineNumber.putShort(start.position);
lineNumber.putShort(line);
}
public void visitMaxs(final int maxStack, final int maxLocals) {
if (computeMaxs) {
// true (non relative) max stack size
int max = 0;
/*
* control flow analysis algorithm: while the block stack is not
* empty, pop a block from this stack, update the max stack size,
* compute the true (non relative) begin stack size of the
* successors of this block, and push these successors onto the
* stack (unless they have already been pushed onto the stack).
* Note: by hypothesis, the {@link Label#beginStackSize} of the
* blocks in the block stack are the true (non relative) beginning
* stack sizes of these blocks.
*/
Label stack = blockStack;
while (stack != null) {
// pops a block from the stack
Label l = stack;
stack = stack.next;
// computes the true (non relative) max stack size of this block
int start = l.beginStackSize;
int blockMax = start + l.maxStackSize;
// updates the global max stack size
if (blockMax > max) {
max = blockMax;
}
// analyses the successors of the block
Edge b = l.successors;
while (b != null) {
l = b.successor;
// if this successor has not already been pushed onto the
// stack...
if (!l.pushed) {
// computes the true beginning stack size of this
// successor block
l.beginStackSize = start + b.stackSize;
// pushes this successor onto the stack
l.pushed = true;
l.next = stack;
stack = l;
}
b = b.next;
}
}
this.maxStack = max;
} else {
this.maxStack = maxStack;
this.maxLocals = maxLocals;
}
}
public void visitEnd() {
}
// ------------------------------------------------------------------------
// Utility methods: control flow analysis algorithm
// ------------------------------------------------------------------------
/**
* Computes the size of the arguments and of the return value of a method.
*
* @param desc the descriptor of a method.
* @return the size of the arguments of the method (plus one for the
* implicit this argument), argSize, and the size of its return
* value, retSize, packed into a single int i =
* (argSize << 2) | retSize (argSize is therefore equal
* to i >> 2, and retSize to i & 0x03).
*/
private static int getArgumentsAndReturnSizes(final String desc) {
int n = 1;
int c = 1;
while (true) {
char car = desc.charAt(c++);
if (car == ')') {
car = desc.charAt(c);
return n << 2
| (car == 'V' ? 0 : (car == 'D' || car == 'J' ? 2 : 1));
} else if (car == 'L') {
while (desc.charAt(c++) != ';') {
}
n += 1;
} else if (car == '[') {
while ((car = desc.charAt(c)) == '[') {
++c;
}
if (car == 'D' || car == 'J') {
n -= 1;
}
} else if (car == 'D' || car == 'J') {
n += 2;
} else {
n += 1;
}
}
}
/**
* Adds a successor to the {@link #currentBlock currentBlock} block.
*
* @param stackSize the current (relative) stack size in the current block.
* @param successor the successor block to be added to the current block.
*/
private void addSuccessor(final int stackSize, final Label successor) {
Edge b = new Edge();
// initializes the previous Edge object...
b.stackSize = stackSize;
b.successor = successor;
// ...and adds it to the successor list of the currentBlock block
b.next = currentBlock.successors;
currentBlock.successors = b;
}
// ------------------------------------------------------------------------
// Utility methods: dump bytecode array
// ------------------------------------------------------------------------
/**
* Returns the size of the bytecode of this method.
*
* @return the size of the bytecode of this method.
*/
final int getSize() {
if (classReaderOffset != 0) {
return 6 + classReaderLength;
}
if (resize) {
// replaces the temporary jump opcodes introduced by Label.resolve.
resizeInstructions(new int[0], new int[0], 0);
}
int size = 8;
if (code.length > 0) {
cw.newUTF8("Code");
size += 18 + code.length + 8 * catchCount;
if (localVar != null) {
cw.newUTF8("LocalVariableTable");
size += 8 + localVar.length;
}
if (localVarType != null) {
cw.newUTF8("LocalVariableTypeTable");
size += 8 + localVarType.length;
}
if (lineNumber != null) {
cw.newUTF8("LineNumberTable");
size += 8 + lineNumber.length;
}
if (cattrs != null) {
size += cattrs.getSize(cw,
code.data,
code.length,
maxStack,
maxLocals);
}
}
if (exceptionCount > 0) {
cw.newUTF8("Exceptions");
size += 8 + 2 * exceptionCount;
}
if ((access & Opcodes.ACC_SYNTHETIC) != 0
&& (cw.version & 0xffff) < Opcodes.V1_5)
{
cw.newUTF8("Synthetic");
size += 6;
}
if ((access & Opcodes.ACC_DEPRECATED) != 0) {
cw.newUTF8("Deprecated");
size += 6;
}
if (cw.version == Opcodes.V1_4) {
if ((access & Opcodes.ACC_VARARGS) != 0) {
cw.newUTF8("Varargs");
size += 6;
}
if ((access & Opcodes.ACC_BRIDGE) != 0) {
cw.newUTF8("Bridge");
size += 6;
}
}
if (signature != null) {
cw.newUTF8("Signature");
cw.newUTF8(signature);
size += 8;
}
if (annd != null) {
cw.newUTF8("AnnotationDefault");
size += 6 + annd.length;
}
if (anns != null) {
cw.newUTF8("RuntimeVisibleAnnotations");
size += 8 + anns.getSize();
}
if (ianns != null) {
cw.newUTF8("RuntimeInvisibleAnnotations");
size += 8 + ianns.getSize();
}
if (panns != null) {
cw.newUTF8("RuntimeVisibleParameterAnnotations");
size += 7 + 2 * panns.length;
for (int i = panns.length - 1; i >= 0; --i) {
size += panns[i] == null ? 0 : panns[i].getSize();
}
}
if (ipanns != null) {
cw.newUTF8("RuntimeInvisibleParameterAnnotations");
size += 7 + 2 * ipanns.length;
for (int i = ipanns.length - 1; i >= 0; --i) {
size += ipanns[i] == null ? 0 : ipanns[i].getSize();
}
}
if (attrs != null) {
size += attrs.getSize(cw, null, 0, -1, -1);
}
return size;
}
/**
* Puts the bytecode of this method in the given byte vector.
*
* @param out the byte vector into which the bytecode of this method must be
* copied.
*/
final void put(final ByteVector out) {
out.putShort(access).putShort(name).putShort(desc);
if (classReaderOffset != 0) {
out.putByteArray(cw.cr.b, classReaderOffset, classReaderLength);
return;
}
int attributeCount = 0;
if (code.length > 0) {
++attributeCount;
}
if (exceptionCount > 0) {
++attributeCount;
}
if ((access & Opcodes.ACC_SYNTHETIC) != 0
&& (cw.version & 0xffff) < Opcodes.V1_5)
{
++attributeCount;
}
if ((access & Opcodes.ACC_DEPRECATED) != 0) {
++attributeCount;
}
if (cw.version == Opcodes.V1_4) {
if ((access & Opcodes.ACC_VARARGS) != 0) {
++attributeCount;
}
if ((access & Opcodes.ACC_BRIDGE) != 0) {
++attributeCount;
}
}
if (signature != null) {
++attributeCount;
}
if (annd != null) {
++attributeCount;
}
if (anns != null) {
++attributeCount;
}
if (ianns != null) {
++attributeCount;
}
if (panns != null) {
++attributeCount;
}
if (ipanns != null) {
++attributeCount;
}
if (attrs != null) {
attributeCount += attrs.getCount();
}
out.putShort(attributeCount);
if (code.length > 0) {
int size = 12 + code.length + 8 * catchCount;
if (localVar != null) {
size += 8 + localVar.length;
}
if (localVarType != null) {
size += 8 + localVarType.length;
}
if (lineNumber != null) {
size += 8 + lineNumber.length;
}
if (cattrs != null) {
size += cattrs.getSize(cw,
code.data,
code.length,
maxStack,
maxLocals);
}
out.putShort(cw.newUTF8("Code")).putInt(size);
out.putShort(maxStack).putShort(maxLocals);
out.putInt(code.length).putByteArray(code.data, 0, code.length);
out.putShort(catchCount);
if (catchCount > 0) {
Handler h = catchTable;
while (h != null) {
out.putShort(h.start.position)
.putShort(h.end.position)
.putShort(h.handler.position)
.putShort(h.type);
h = h.next;
}
}
attributeCount = 0;
if (localVar != null) {
++attributeCount;
}
if (localVarType != null) {
++attributeCount;
}
if (lineNumber != null) {
++attributeCount;
}
if (cattrs != null) {
attributeCount += cattrs.getCount();
}
out.putShort(attributeCount);
if (localVar != null) {
out.putShort(cw.newUTF8("LocalVariableTable"));
out.putInt(localVar.length + 2).putShort(localVarCount);
out.putByteArray(localVar.data, 0, localVar.length);
}
if (localVarType != null) {
out.putShort(cw.newUTF8("LocalVariableTypeTable"));
out.putInt(localVarType.length + 2).putShort(localVarTypeCount);
out.putByteArray(localVarType.data, 0, localVarType.length);
}
if (lineNumber != null) {
out.putShort(cw.newUTF8("LineNumberTable"));
out.putInt(lineNumber.length + 2).putShort(lineNumberCount);
out.putByteArray(lineNumber.data, 0, lineNumber.length);
}
if (cattrs != null) {
cattrs.put(cw, code.data, code.length, maxLocals, maxStack, out);
}
}
if (exceptionCount > 0) {
out.putShort(cw.newUTF8("Exceptions"))
.putInt(2 * exceptionCount + 2);
out.putShort(exceptionCount);
for (int i = 0; i < exceptionCount; ++i) {
out.putShort(exceptions[i]);
}
}
if ((access & Opcodes.ACC_SYNTHETIC) != 0
&& (cw.version & 0xffff) < Opcodes.V1_5)
{
out.putShort(cw.newUTF8("Synthetic")).putInt(0);
}
if ((access & Opcodes.ACC_DEPRECATED) != 0) {
out.putShort(cw.newUTF8("Deprecated")).putInt(0);
}
if (cw.version == Opcodes.V1_4) {
if ((access & Opcodes.ACC_VARARGS) != 0) {
out.putShort(cw.newUTF8("Varargs")).putInt(0);
}
if ((access & Opcodes.ACC_BRIDGE) != 0) {
out.putShort(cw.newUTF8("Bridge")).putInt(0);
}
}
if (signature != null) {
out.putShort(cw.newUTF8("Signature"))
.putInt(2)
.putShort(cw.newUTF8(signature));
}
if (annd != null) {
out.putShort(cw.newUTF8("AnnotationDefault"));
out.putInt(annd.length);
out.putByteArray(annd.data, 0, annd.length);
}
if (anns != null) {
out.putShort(cw.newUTF8("RuntimeVisibleAnnotations"));
anns.put(out);
}
if (ianns != null) {
out.putShort(cw.newUTF8("RuntimeInvisibleAnnotations"));
ianns.put(out);
}
if (panns != null) {
out.putShort(cw.newUTF8("RuntimeVisibleParameterAnnotations"));
AnnotationWriter.put(panns, out);
}
if (ipanns != null) {
out.putShort(cw.newUTF8("RuntimeInvisibleParameterAnnotations"));
AnnotationWriter.put(ipanns, out);
}
if (attrs != null) {
attrs.put(cw, null, 0, -1, -1, out);
}
}
// ------------------------------------------------------------------------
// Utility methods: instruction resizing (used to handle GOTO_W and JSR_W)
// ------------------------------------------------------------------------
/**
* Resizes the designated instructions, while keeping jump offsets and
* instruction addresses consistent. This may require to resize other
* existing instructions, or even to introduce new instructions: for
* example, increasing the size of an instruction by 2 at the middle of a
* method can increases the offset of an IFEQ instruction from 32766 to
* 32768, in which case IFEQ 32766 must be replaced with IFNEQ 8 GOTO_W
* 32765. This, in turn, may require to increase the size of another jump
* instruction, and so on... All these operations are handled automatically
* by this method. This method must be called after all the method
* that is being built has been visited. In particular, the
* {@link Label Label} objects used to construct the method are no longer
* valid after this method has been called.
*
* @param indexes current positions of the instructions to be resized. Each
* instruction must be designated by the index of its last
* byte, plus one (or, in other words, by the index of the first
* byte of the next instruction).
* @param sizes the number of bytes to be added to the above
* instructions. More precisely, for each i < len,
* sizes[i] bytes will be added at the end of the
* instruction designated by indexes[i] or, if
* sizes[i] is negative, the last |sizes[i]|
* bytes of the instruction will be removed (the instruction size
* must not become negative or null). The gaps introduced by
* this method must be filled in "manually" in {@link #code code}
* method.
* @param len the number of instruction to be resized. Must be smaller than
* or equal to indexes.length and sizes.length.
* @return the indexes array, which now contains the new
* positions of the resized instructions (designated as above).
*/
private int[] resizeInstructions(
final int[] indexes,
final int[] sizes,
final int len)
{
byte[] b = code.data; // bytecode of the method
int u, v, label; // indexes in b
int i, j; // loop indexes
/*
* 1st step: As explained above, resizing an instruction may require to
* resize another one, which may require to resize yet another one, and
* so on. The first step of the algorithm consists in finding all the
* instructions that need to be resized, without modifying the code.
* This is done by the following "fix point" algorithm:
*
* Parse the code to find the jump instructions whose offset will need
* more than 2 bytes to be stored (the future offset is computed from
* the current offset and from the number of bytes that will be inserted
* or removed between the source and target instructions). For each such
* instruction, adds an entry in (a copy of) the indexes and sizes
* arrays (if this has not already been done in a previous iteration!).
*
* If at least one entry has been added during the previous step, go
* back to the beginning, otherwise stop.
*
* In fact the real algorithm is complicated by the fact that the size
* of TABLESWITCH and LOOKUPSWITCH instructions depends on their
* position in the bytecode (because of padding). In order to ensure the
* convergence of the algorithm, the number of bytes to be added or
* removed from these instructions is over estimated during the previous
* loop, and computed exactly only after the loop is finished (this
* requires another pass to parse the bytecode of the method).
*/
int[] allIndexes = new int[len]; // copy of indexes
int[] allSizes = new int[len]; // copy of sizes
boolean[] resize; // instructions to be resized
int newOffset; // future offset of a jump instruction
System.arraycopy(indexes, 0, allIndexes, 0, len);
System.arraycopy(sizes, 0, allSizes, 0, len);
resize = new boolean[code.length];
// 3 = loop again, 2 = loop ended, 1 = last pass, 0 = done
int state = 3;
do {
if (state == 3) {
state = 2;
}
u = 0;
while (u < b.length) {
int opcode = b[u] & 0xFF; // opcode of current instruction
int insert = 0; // bytes to be added after this instruction
switch (ClassWriter.TYPE[opcode]) {
case ClassWriter.NOARG_INSN:
case ClassWriter.IMPLVAR_INSN:
u += 1;
break;
case ClassWriter.LABEL_INSN:
if (opcode > 201) {
// converts temporary opcodes 202 to 217, 218 and
// 219 to IFEQ ... JSR (inclusive), IFNULL and
// IFNONNULL
opcode = opcode < 218 ? opcode - 49 : opcode - 20;
label = u + readUnsignedShort(b, u + 1);
} else {
label = u + readShort(b, u + 1);
}
newOffset = getNewOffset(allIndexes, allSizes, u, label);
if (newOffset < Short.MIN_VALUE
|| newOffset > Short.MAX_VALUE)
{
if (!resize[u]) {
if (opcode == Opcodes.GOTO
|| opcode == Opcodes.JSR)
{
// two additional bytes will be required to
// replace this GOTO or JSR instruction with
// a GOTO_W or a JSR_W
insert = 2;
} else {
// five additional bytes will be required to
// replace this IFxxx instruction with
// IFNOTxxx GOTO_W , where IFNOTxxx
// is the "opposite" opcode of IFxxx (i.e.,
// IFNE for IFEQ) and where designates
// the instruction just after the GOTO_W.
insert = 5;
}
resize[u] = true;
}
}
u += 3;
break;
case ClassWriter.LABELW_INSN:
u += 5;
break;
case ClassWriter.TABL_INSN:
if (state == 1) {
// true number of bytes to be added (or removed)
// from this instruction = (future number of padding
// bytes - current number of padding byte) -
// previously over estimated variation =
// = ((3 - newOffset%4) - (3 - u%4)) - u%4
// = (-newOffset%4 + u%4) - u%4
// = -(newOffset & 3)
newOffset = getNewOffset(allIndexes, allSizes, 0, u);
insert = -(newOffset & 3);
} else if (!resize[u]) {
// over estimation of the number of bytes to be
// added to this instruction = 3 - current number
// of padding bytes = 3 - (3 - u%4) = u%4 = u & 3
insert = u & 3;
resize[u] = true;
}
// skips instruction
u = u + 4 - (u & 3);
u += 4 * (readInt(b, u + 8) - readInt(b, u + 4) + 1) + 12;
break;
case ClassWriter.LOOK_INSN:
if (state == 1) {
// like TABL_INSN
newOffset = getNewOffset(allIndexes, allSizes, 0, u);
insert = -(newOffset & 3);
} else if (!resize[u]) {
// like TABL_INSN
insert = u & 3;
resize[u] = true;
}
// skips instruction
u = u + 4 - (u & 3);
u += 8 * readInt(b, u + 4) + 8;
break;
case ClassWriter.WIDE_INSN:
opcode = b[u + 1] & 0xFF;
if (opcode == Opcodes.IINC) {
u += 6;
} else {
u += 4;
}
break;
case ClassWriter.VAR_INSN:
case ClassWriter.SBYTE_INSN:
case ClassWriter.LDC_INSN:
u += 2;
break;
case ClassWriter.SHORT_INSN:
case ClassWriter.LDCW_INSN:
case ClassWriter.FIELDORMETH_INSN:
case ClassWriter.TYPE_INSN:
case ClassWriter.IINC_INSN:
u += 3;
break;
case ClassWriter.ITFMETH_INSN:
u += 5;
break;
// case ClassWriter.MANA_INSN:
default:
u += 4;
break;
}
if (insert != 0) {
// adds a new (u, insert) entry in the allIndexes and
// allSizes arrays
int[] newIndexes = new int[allIndexes.length + 1];
int[] newSizes = new int[allSizes.length + 1];
System.arraycopy(allIndexes,
0,
newIndexes,
0,
allIndexes.length);
System.arraycopy(allSizes, 0, newSizes, 0, allSizes.length);
newIndexes[allIndexes.length] = u;
newSizes[allSizes.length] = insert;
allIndexes = newIndexes;
allSizes = newSizes;
if (insert > 0) {
state = 3;
}
}
}
if (state < 3) {
--state;
}
} while (state != 0);
// 2nd step:
// copies the bytecode of the method into a new bytevector, updates the
// offsets, and inserts (or removes) bytes as requested.
ByteVector newCode = new ByteVector(code.length);
u = 0;
while (u < code.length) {
for (i = allIndexes.length - 1; i >= 0; --i) {
if (allIndexes[i] == u) {
if (i < len) {
if (sizes[i] > 0) {
newCode.putByteArray(null, 0, sizes[i]);
} else {
newCode.length += sizes[i];
}
indexes[i] = newCode.length;
}
}
}
int opcode = b[u] & 0xFF;
switch (ClassWriter.TYPE[opcode]) {
case ClassWriter.NOARG_INSN:
case ClassWriter.IMPLVAR_INSN:
newCode.putByte(opcode);
u += 1;
break;
case ClassWriter.LABEL_INSN:
if (opcode > 201) {
// changes temporary opcodes 202 to 217 (inclusive), 218
// and 219 to IFEQ ... JSR (inclusive), IFNULL and
// IFNONNULL
opcode = opcode < 218 ? opcode - 49 : opcode - 20;
label = u + readUnsignedShort(b, u + 1);
} else {
label = u + readShort(b, u + 1);
}
newOffset = getNewOffset(allIndexes, allSizes, u, label);
if (resize[u]) {
// replaces GOTO with GOTO_W, JSR with JSR_W and IFxxx
// with IFNOTxxx GOTO_W , where IFNOTxxx is
// the "opposite" opcode of IFxxx (i.e., IFNE for IFEQ)
// and where designates the instruction just after
// the GOTO_W.
if (opcode == Opcodes.GOTO) {
newCode.putByte(200); // GOTO_W
} else if (opcode == Opcodes.JSR) {
newCode.putByte(201); // JSR_W
} else {
newCode.putByte(opcode <= 166
? ((opcode + 1) ^ 1) - 1
: opcode ^ 1);
newCode.putShort(8); // jump offset
newCode.putByte(200); // GOTO_W
// newOffset now computed from start of GOTO_W
newOffset -= 3;
}
newCode.putInt(newOffset);
} else {
newCode.putByte(opcode);
newCode.putShort(newOffset);
}
u += 3;
break;
case ClassWriter.LABELW_INSN:
label = u + readInt(b, u + 1);
newOffset = getNewOffset(allIndexes, allSizes, u, label);
newCode.putByte(opcode);
newCode.putInt(newOffset);
u += 5;
break;
case ClassWriter.TABL_INSN:
// skips 0 to 3 padding bytes
v = u;
u = u + 4 - (v & 3);
// reads and copies instruction
newCode.putByte(Opcodes.TABLESWITCH);
while (newCode.length % 4 != 0) {
newCode.putByte(0);
}
label = v + readInt(b, u);
u += 4;
newOffset = getNewOffset(allIndexes, allSizes, v, label);
newCode.putInt(newOffset);
j = readInt(b, u);
u += 4;
newCode.putInt(j);
j = readInt(b, u) - j + 1;
u += 4;
newCode.putInt(readInt(b, u - 4));
for (; j > 0; --j) {
label = v + readInt(b, u);
u += 4;
newOffset = getNewOffset(allIndexes, allSizes, v, label);
newCode.putInt(newOffset);
}
break;
case ClassWriter.LOOK_INSN:
// skips 0 to 3 padding bytes
v = u;
u = u + 4 - (v & 3);
// reads and copies instruction
newCode.putByte(Opcodes.LOOKUPSWITCH);
while (newCode.length % 4 != 0) {
newCode.putByte(0);
}
label = v + readInt(b, u);
u += 4;
newOffset = getNewOffset(allIndexes, allSizes, v, label);
newCode.putInt(newOffset);
j = readInt(b, u);
u += 4;
newCode.putInt(j);
for (; j > 0; --j) {
newCode.putInt(readInt(b, u));
u += 4;
label = v + readInt(b, u);
u += 4;
newOffset = getNewOffset(allIndexes, allSizes, v, label);
newCode.putInt(newOffset);
}
break;
case ClassWriter.WIDE_INSN:
opcode = b[u + 1] & 0xFF;
if (opcode == Opcodes.IINC) {
newCode.putByteArray(b, u, 6);
u += 6;
} else {
newCode.putByteArray(b, u, 4);
u += 4;
}
break;
case ClassWriter.VAR_INSN:
case ClassWriter.SBYTE_INSN:
case ClassWriter.LDC_INSN:
newCode.putByteArray(b, u, 2);
u += 2;
break;
case ClassWriter.SHORT_INSN:
case ClassWriter.LDCW_INSN:
case ClassWriter.FIELDORMETH_INSN:
case ClassWriter.TYPE_INSN:
case ClassWriter.IINC_INSN:
newCode.putByteArray(b, u, 3);
u += 3;
break;
case ClassWriter.ITFMETH_INSN:
newCode.putByteArray(b, u, 5);
u += 5;
break;
// case MANA_INSN:
default:
newCode.putByteArray(b, u, 4);
u += 4;
break;
}
}
// updates the exception handler block labels
Handler h = catchTable;
while (h != null) {
getNewOffset(allIndexes, allSizes, h.start);
getNewOffset(allIndexes, allSizes, h.end);
getNewOffset(allIndexes, allSizes, h.handler);
h = h.next;
}
for (i = 0; i < 2; ++i) {
ByteVector bv = i == 0 ? localVar : localVarType;
if (bv != null) {
b = bv.data;
u = 0;
while (u < bv.length) {
label = readUnsignedShort(b, u);
newOffset = getNewOffset(allIndexes, allSizes, 0, label);
writeShort(b, u, newOffset);
label += readUnsignedShort(b, u + 2);
newOffset = getNewOffset(allIndexes, allSizes, 0, label)
- newOffset;
writeShort(b, u + 2, newOffset);
u += 10;
}
}
}
if (lineNumber != null) {
b = lineNumber.data;
u = 0;
while (u < lineNumber.length) {
writeShort(b, u, getNewOffset(allIndexes,
allSizes,
0,
readUnsignedShort(b, u)));
u += 4;
}
}
// updates the labels of the other attributes
while (cattrs != null) {
Label[] labels = cattrs.getLabels();
if (labels != null) {
for (i = labels.length - 1; i >= 0; --i) {
if (!labels[i].resized) {
labels[i].position = getNewOffset(allIndexes,
allSizes,
0,
labels[i].position);
labels[i].resized = true;
}
}
}
}
// replaces old bytecodes with new ones
code = newCode;
// returns the positions of the resized instructions
return indexes;
}
/**
* Reads an unsigned short value in the given byte array.
*
* @param b a byte array.
* @param index the start index of the value to be read.
* @return the read value.
*/
static int readUnsignedShort(final byte[] b, final int index) {
return ((b[index] & 0xFF) << 8) | (b[index + 1] & 0xFF);
}
/**
* Reads a signed short value in the given byte array.
*
* @param b a byte array.
* @param index the start index of the value to be read.
* @return the read value.
*/
static short readShort(final byte[] b, final int index) {
return (short) (((b[index] & 0xFF) << 8) | (b[index + 1] & 0xFF));
}
/**
* Reads a signed int value in the given byte array.
*
* @param b a byte array.
* @param index the start index of the value to be read.
* @return the read value.
*/
static int readInt(final byte[] b, final int index) {
return ((b[index] & 0xFF) << 24) | ((b[index + 1] & 0xFF) << 16)
| ((b[index + 2] & 0xFF) << 8) | (b[index + 3] & 0xFF);
}
/**
* Writes a short value in the given byte array.
*
* @param b a byte array.
* @param index where the first byte of the short value must be written.
* @param s the value to be written in the given byte array.
*/
static void writeShort(final byte[] b, final int index, final int s) {
b[index] = (byte) (s >>> 8);
b[index + 1] = (byte) s;
}
/**
* Computes the future value of a bytecode offset. Note: it is possible
* to have several entries for the same instruction in the indexes
* and sizes: two entries (index=a,size=b) and (index=a,size=b')
* are equivalent to a single entry (index=a,size=b+b').
*
* @param indexes current positions of the instructions to be resized. Each
* instruction must be designated by the index of its last
* byte, plus one (or, in other words, by the index of the first
* byte of the next instruction).
* @param sizes the number of bytes to be added to the above
* instructions. More precisely, for each i < len,
* sizes[i] bytes will be added at the end of the
* instruction designated by indexes[i] or, if
* sizes[i] is negative, the last |sizes[i]|
* bytes of the instruction will be removed (the instruction size
* must not become negative or null).
* @param begin index of the first byte of the source instruction.
* @param end index of the first byte of the target instruction.
* @return the future value of the given bytecode offset.
*/
static int getNewOffset(
final int[] indexes,
final int[] sizes,
final int begin,
final int end)
{
int offset = end - begin;
for (int i = 0; i < indexes.length; ++i) {
if (begin < indexes[i] && indexes[i] <= end) {
// forward jump
offset += sizes[i];
} else if (end < indexes[i] && indexes[i] <= begin) {
// backward jump
offset -= sizes[i];
}
}
return offset;
}
/**
* Updates the offset of the given label.
*
* @param indexes current positions of the instructions to be resized. Each
* instruction must be designated by the index of its last
* byte, plus one (or, in other words, by the index of the first
* byte of the next instruction).
* @param sizes the number of bytes to be added to the above
* instructions. More precisely, for each i < len,
* sizes[i] bytes will be added at the end of the
* instruction designated by indexes[i] or, if
* sizes[i] is negative, the last |sizes[i]|
* bytes of the instruction will be removed (the instruction size
* must not become negative or null).
* @param label the label whose offset must be updated.
*/
static void getNewOffset(
final int[] indexes,
final int[] sizes,
final Label label)
{
if (!label.resized) {
label.position = getNewOffset(indexes, sizes, 0, label.position);
label.resized = true;
}
}
}