webit.script.asm3.MethodWriter Maven / Gradle / Ivy
/***
* ASM: a very small and fast Java bytecode manipulation framework
* Copyright (c) 2000-2007 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 webit.script.asm3;
/**
* 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
* @author Eugene Kuleshov
*/
public class MethodWriter{
/**
* Pseudo access flag used to denote constructors.
*/
static final int ACC_CONSTRUCTOR = 262144;
//
// /**
// * Frame has exactly the same locals as the previous stack map frame and
// * number of stack items is zero.
// */
// private static final int SAME_FRAME = 0; // to 63 (0-3f)
//
// /**
// * Frame has exactly the same locals as the previous stack map frame and
// * number of stack items is 1
// */
// private static final int SAME_LOCALS_1_STACK_ITEM_FRAME = 64; // to 127 (40-7f)
//
// /**
// * Reserved for future use
// */
// private static final int RESERVED = 128;
//
// /**
// * Frame has exactly the same locals as the previous stack map frame and
// * number of stack items is 1. Offset is bigger then 63;
// */
// private static final int SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED = 247; // f7
//
// /**
// * Frame where current locals are the same as the locals in the previous
// * frame, except that the k last locals are absent. The value of k is given
// * by the formula 251-frame_type.
// */
// private static final int CHOP_FRAME = 248; // to 250 (f8-fA)
//
// /**
// * Frame has exactly the same locals as the previous stack map frame and
// * number of stack items is zero. Offset is bigger then 63;
// */
// private static final int SAME_FRAME_EXTENDED = 251; // fb
//
// /**
// * Frame where current locals are the same as the locals in the previous
// * frame, except that k additional locals are defined. The value of k is
// * given by the formula frame_type-251.
// */
// private static final int APPEND_FRAME = 252; // to 254 // fc-fe
//
// /**
// * Full frame
// */
// private static final int FULL_FRAME = 255; // ff
/**
* Indicates that the stack map frames must be recomputed from scratch. In
* this case the maximum stack size and number of local variables is also
* recomputed from scratch.
*
* @see #compute
*/
// private static final int FRAMES = 0;
/**
* Indicates that the maximum stack size and number of local variables must
* be automatically computed.
*
* @see #compute
*/
private static final int MAXS = 1;
/**
* Indicates that nothing must be automatically computed.
*
* @see #compute
*/
private static final int NOTHING = 2;
/**
* Next method writer (see {@link ClassWriter#firstMethod firstMethod}).
*/
MethodWriter next;
/**
* The class writer to which this method must be added.
*/
private final 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 final int name;
/**
* The index of the constant pool item that contains the descriptor of this
* method.
*/
private final int desc;
/**
* The descriptor of this method.
*/
private final String descriptor;
/**
* 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 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 stack map frames in the StackMapTable attribute.
*/
private int frameCount;
/**
* The StackMapTable attribute.
*/
private ByteVector stackMap;
// /**
// * The offset of the last frame that was written in the StackMapTable
// * attribute.
// */
// private int previousFrameOffset;
// /**
// * The last frame that was written in the StackMapTable attribute.
// *
// * @see #frame
// */
// private int[] previousFrame;
//
// /**
// * Index of the next element to be added in {@link #frame}.
// */
// private int frameIndex;
// /**
// * The current stack map frame. The first element contains the offset of the
// * instruction to which the frame corresponds, the second element is the
// * number of locals and the third one is the number of stack elements. The
// * local variables start at index 3 and are followed by the operand stack
// * values. In summary frame[0] = offset, frame[1] = nLocal, frame[2] =
// * nStack, frame[3] = nLocal. All types are encoded as integers, with the
// * same format as the one used in {@link Label}, but limited to BASE types.
// */
// private int[] frame;
/**
* Number of elements in the exception handler list.
*/
private int handlerCount;
// /**
// * The first element in the exception handler list.
// */
// private Handler firstHandler;
// /**
// * The last element in the exception 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;
/**
* Indicates if some jump instructions are too small and need to be resized.
*/
private boolean resize;
/**
* The number of subroutines in this method.
*/
private int subroutines;
// ------------------------------------------------------------------------
/*
* 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.
*/
/**
* Indicates what must be automatically computed.
*
* @see #FRAMES
* @see #MAXS
* @see #NOTHING
*/
private final int compute;
/**
* A list of labels. This list is the list of basic blocks in the method,
* i.e. a list of Label objects linked to each other by their
* {@link Label#successor} field, in the order they are visited by
* {@link MethodVisitor#visitLabel}, and starting with the first basic block.
*/
private Label labels;
/**
* The previous basic block.
*/
private Label previousBlock;
/**
* The current basic block.
*/
private Label currentBlock;
/**
* 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#inputStackTop 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#inputStackTop beginStackSize} of the current basic
* block plus stackSize.
*/
private int maxStackSize;
// ------------------------------------------------------------------------
// 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.
* @param computeFrames true if the stack map tables must be
* recomputed from scratch.
*/
MethodWriter(
final ClassWriter cw,
final int access,
final String name,
final String desc,
final String signature,
final String[] exceptions,
final boolean computeMaxs,
final boolean computeFrames)
{
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.compute = computeFrames ? FRAMES : (computeMaxs ? MAXS : NOTHING);
this.compute = computeMaxs ? MAXS : NOTHING;
if (computeMaxs || computeFrames) {
if (computeFrames && "".equals(name)) {
this.access |= ACC_CONSTRUCTOR;
}
// updates maxLocals
int size = Type.getArgumentsAndReturnSizes(descriptor) >> 2;
if ((access & Opcodes.ACC_STATIC) != 0) {
--size;
}
maxLocals = size;
// creates and visits the label for the first basic block
labels = new Label();
labels.status |= Label.PUSHED;
visitLabel(labels);
}
}
// ------------------------------------------------------------------------
// Implementation of the MethodVisitor interface
// ------------------------------------------------------------------------
// public void visitCode() {
// }
//
// public void visitFrame(
// final int type,
// final int nLocal,
// final Object[] local,
// final int nStack,
// final Object[] stack)
// {
//
// if (type == Opcodes.F_NEW) {
// startFrame(code.length, nLocal, nStack);
// for (int i = 0; i < nLocal; ++i) {
// if (local[i] instanceof String) {
// frame[frameIndex++] = Frame.OBJECT
// | cw.addType((String) local[i]);
// } else if (local[i] instanceof Integer) {
// frame[frameIndex++] = ((Integer) local[i]).intValue();
// } else {
// frame[frameIndex++] = Frame.UNINITIALIZED
// | cw.addUninitializedType("",
// ((Label) local[i]).position);
// }
// }
// for (int i = 0; i < nStack; ++i) {
// if (stack[i] instanceof String) {
// frame[frameIndex++] = Frame.OBJECT
// | cw.addType((String) stack[i]);
// } else if (stack[i] instanceof Integer) {
// frame[frameIndex++] = ((Integer) stack[i]).intValue();
// } else {
// frame[frameIndex++] = Frame.UNINITIALIZED
// | cw.addUninitializedType("",
// ((Label) stack[i]).position);
// }
// }
// endFrame();
// } else {
// int delta;
// if (stackMap == null) {
// stackMap = new ByteVector();
// delta = code.length;
// } else {
// delta = code.length - previousFrameOffset - 1;
// if (delta < 0) {
// if (type == Opcodes.F_SAME) {
// return;
// } else {
// throw new IllegalStateException();
// }
// }
// }
//
// switch (type) {
// case Opcodes.F_FULL:
// stackMap.putByte(FULL_FRAME)
// .putShort(delta)
// .putShort(nLocal);
// for (int i = 0; i < nLocal; ++i) {
// writeFrameType(local[i]);
// }
// stackMap.putShort(nStack);
// for (int i = 0; i < nStack; ++i) {
// writeFrameType(stack[i]);
// }
// break;
// case Opcodes.F_APPEND:
// stackMap.putByte(SAME_FRAME_EXTENDED + nLocal)
// .putShort(delta);
// for (int i = 0; i < nLocal; ++i) {
// writeFrameType(local[i]);
// }
// break;
// case Opcodes.F_CHOP:
// stackMap.putByte(SAME_FRAME_EXTENDED - nLocal)
// .putShort(delta);
// break;
// case Opcodes.F_SAME:
// if (delta < 64) {
// stackMap.putByte(delta);
// } else {
// stackMap.putByte(SAME_FRAME_EXTENDED).putShort(delta);
// }
// break;
// case Opcodes.F_SAME1:
// if (delta < 64) {
// stackMap.putByte(SAME_LOCALS_1_STACK_ITEM_FRAME + delta);
// } else {
// stackMap.putByte(SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED)
// .putShort(delta);
// }
// writeFrameType(stack[0]);
// break;
// }
//
// previousFrameOffset = code.length;
// ++frameCount;
// }
// }
public void visitInsn(final int opcode) {
// adds the instruction to the bytecode of the method
code.putByte(opcode);
// update currentBlock
// Label currentBlock = this.currentBlock;
if (currentBlock != null) {
// if (compute == FRAMES) {
// currentBlock.frame.execute(opcode, 0, null, null);
// } else
{
// updates current and max stack sizes
int size = stackSize + Frame.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)
{
noSuccessor();
}
}
}
public void visitIntInsn(final int opcode, final int operand) {
// Label currentBlock = this.currentBlock;
if (currentBlock != null) {
// if (compute == FRAMES) {
// currentBlock.frame.execute(opcode, operand, null, null);
// } else
if (opcode != Opcodes.NEWARRAY) {
// updates current and max stack sizes only for 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) {
// Label currentBlock = this.currentBlock;
if (currentBlock != null) {
// if (compute == FRAMES) {
// currentBlock.frame.execute(opcode, var, null, null);
// } else
{
// updates current and max stack sizes
if (opcode == Opcodes.RET) {
// no stack change, but end of current block (no successor)
currentBlock.status |= Label.RET;
// save 'stackSize' here for future use
// (see {@link #findSubroutineSuccessors})
currentBlock.inputStackTop = stackSize;
noSuccessor();
} else { // xLOAD or xSTORE
int size = stackSize + Frame.SIZE[opcode];
if (size > maxStackSize) {
maxStackSize = size;
}
stackSize = size;
}
}
}
if (compute != NOTHING) {
// 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);
}
// if (opcode >= Opcodes.ISTORE && compute == FRAMES && handlerCount > 0) {
// visitLabel(new Label());
// }
}
public void visitTypeInsn(final int opcode, final String type) {
Item i = cw.newClassItem(type);
// Label currentBlock = this.currentBlock;
if (currentBlock != null) {
// if (compute == FRAMES) {
// currentBlock.frame.execute(opcode, code.length, cw, i);
// } else
if (opcode == Opcodes.NEW) {
// updates current and max stack sizes only if opcode == NEW
// (no stack change 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, i.index);
}
public void visitFieldInsn(
final int opcode,
final String owner,
final String name,
final String desc)
{
Item i = cw.newFieldItem(owner, name, desc);
// Label currentBlock = this.currentBlock;
if (currentBlock != null) {
// if (compute == FRAMES) {
// currentBlock.frame.execute(opcode, 0, cw, i);
// } else
{
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, i.index);
}
public void visitMethodInsn(
final int opcode,
final String owner,
final String name,
final String desc)
{
boolean itf = opcode == Opcodes.INVOKEINTERFACE;
Item i = (opcode == Opcodes.INVOKEDYNAMIC) ?
cw.newNameTypeItem(name, desc):
cw.newMethodItem(owner, name, desc, itf);
int argSize = i.intVal;
// Label currentBlock = this.currentBlock;
if (currentBlock != null) {
// if (compute == FRAMES) {
// currentBlock.frame.execute(opcode, 0, cw, i);
// } else
{
/*
* 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 = Type.getArgumentsAndReturnSizes(desc);
// ... and we save them in order
// not to recompute them in the future
i.intVal = argSize;
}
int size;
if (opcode == Opcodes.INVOKESTATIC || opcode == Opcodes.INVOKEDYNAMIC) {
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 (argSize == 0) {
argSize = Type.getArgumentsAndReturnSizes(desc);
i.intVal = argSize;
}
code.put12(Opcodes.INVOKEINTERFACE, i.index).put11(argSize >> 2, 0);
} else {
code.put12(opcode, i.index);
if (opcode==Opcodes.INVOKEDYNAMIC) {
code.putShort(0);
}
}
}
public void visitJumpInsn(final int opcode, final Label label) {
Label nextInsn = null;
// Label currentBlock = this.currentBlock;
if (currentBlock != null) {
// if (compute == FRAMES) {
// currentBlock.frame.execute(opcode, 0, null, null);
// // 'label' is the target of a jump instruction
// label.getFirst().status |= Label.TARGET;
// // adds 'label' as a successor of this basic block
// addSuccessor(Edge.NORMAL, label);
// if (opcode != Opcodes.GOTO) {
// // creates a Label for the next basic block
// nextInsn = new Label();
// }
// } else
{
if (opcode == Opcodes.JSR) {
if ((label.status & Label.SUBROUTINE) == 0) {
label.status |= Label.SUBROUTINE;
++subroutines;
}
currentBlock.status |= Label.JSR;
addSuccessor(stackSize + 1, label);
// creates a Label for the next basic block
nextInsn = new Label();
/*
* note that, by construction in this method, a JSR block
* has at least two successors in the control flow graph:
* the first one leads the next instruction after the JSR,
* while the second one leads to the JSR target.
*/
} else {
// updates current stack size (max stack size unchanged
// because stack size variation always negative in this
// case)
stackSize += Frame.SIZE[opcode];
addSuccessor(stackSize, label);
}
}
}
// adds the instruction to the bytecode of the method
if ((label.status & Label.RESOLVED) != 0
&& 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 {
// if the IF instruction is transformed into IFNOT GOTO_W the
// next instruction becomes the target of the IFNOT instruction
if (nextInsn != null) {
nextInsn.status |= Label.TARGET;
}
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);
}
if (currentBlock != null) {
if (nextInsn != null) {
// if the jump instruction is not a GOTO, the next instruction
// is also a successor of this instruction. Calling visitLabel
// adds the label of this next instruction as a successor of the
// current block, and starts a new basic block
visitLabel(nextInsn);
}
if (opcode == Opcodes.GOTO) {
noSuccessor();
}
}
}
public void visitLabel(final Label label) {
// resolves previous forward references to label, if any
resize |= label.resolve(this, code.length, code.data);
// updates currentBlock
if ((label.status & Label.DEBUG) != 0) {
return;
}
// if (compute == FRAMES) {
// if (currentBlock != null) {
// if (label.position == currentBlock.position) {
// // successive labels, do not start a new basic block
// currentBlock.status |= (label.status & Label.TARGET);
// label.frame = currentBlock.frame;
// return;
// }
// // ends current block (with one new successor)
// addSuccessor(Edge.NORMAL, label);
// }
// // begins a new current block
// currentBlock = label;
// if (label.frame == null) {
// label.frame = new Frame();
// label.frame.owner = label;
// }
// // updates the basic block list
// if (previousBlock != null) {
// if (label.position == previousBlock.position) {
// previousBlock.status |= (label.status & Label.TARGET);
// label.frame = previousBlock.frame;
// currentBlock = previousBlock;
// return;
// }
// previousBlock.successor = label;
// }
// previousBlock = label;
// } else
if (compute == MAXS) {
if (currentBlock != null) {
// ends current block (with one new successor)
currentBlock.outputStackMax = maxStackSize;
addSuccessor(stackSize, label);
}
// begins a new current block
currentBlock = label;
// resets the relative current and max stack sizes
stackSize = 0;
maxStackSize = 0;
// updates the basic block list
if (previousBlock != null) {
previousBlock.successor = label;
}
previousBlock = label;
}
}
public void visitLdcInsn(final Object cst) {
Item i = cw.newConstItem(cst);
// Label currentBlock = this.currentBlock;
if (currentBlock != null) {
// if (compute == FRAMES) {
// currentBlock.frame.execute(Opcodes.LDC, 0, cw, i);
// } else
{
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 (currentBlock != null) {
// if (compute == FRAMES) {
// currentBlock.frame.execute(Opcodes.IINC, var, null, null);
// }
// }
// if (compute != NOTHING) {
// // updates max locals
// 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)
{
// adds the instruction to the bytecode of the method
int source = code.length;
code.putByte(Opcodes.TABLESWITCH);
code.putByteArray(null, 0, (4 - code.length % 4) % 4);
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);
}
// updates currentBlock
visitSwitchInsn(dflt, labels);
}
public void visitLookupSwitchInsn(
final Label dflt,
final int[] keys,
final Label[] labels)
{
// adds the instruction to the bytecode of the method
int source = code.length;
code.putByte(Opcodes.LOOKUPSWITCH);
code.putByteArray(null, 0, (4 - code.length % 4) % 4);
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);
}
// updates currentBlock
visitSwitchInsn(dflt, labels);
}
private void visitSwitchInsn(final Label dflt, final Label[] labels) {
// Label currentBlock = this.currentBlock;
if (currentBlock != null) {
// if (compute == FRAMES) {
// currentBlock.frame.execute(Opcodes.LOOKUPSWITCH, 0, null, null);
// // adds current block successors
// addSuccessor(Edge.NORMAL, dflt);
// dflt.getFirst().status |= Label.TARGET;
// for (int i = 0; i < labels.length; ++i) {
// addSuccessor(Edge.NORMAL, labels[i]);
// labels[i].getFirst().status |= Label.TARGET;
// }
// } else
{
// updates current stack size (max stack size unchanged)
--stackSize;
// adds current block successors
addSuccessor(stackSize, dflt);
for (int i = 0; i < labels.length; ++i) {
addSuccessor(stackSize, labels[i]);
}
}
// ends current block
noSuccessor();
}
}
// public void visitMultiANewArrayInsn(final String desc, final int dims) {
// Item i = cw.newClassItem(desc);
// // Label currentBlock = this.currentBlock;
// if (currentBlock != null) {
// if (compute == FRAMES) {
// currentBlock.frame.execute(Opcodes.MULTIANEWARRAY, dims, cw, i);
// } else {
// // 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, i.index).putByte(dims);
// }
// public void visitTryCatchBlock(
// final Label start,
// final Label end,
// final Label handler,
// final String type)
// {
// ++handlerCount;
// 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) {
// firstHandler = 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);
// if (compute != NOTHING) {
// // updates max locals
// char c = desc.charAt(0);
// int n = index + (c == 'J' || c == 'D' ? 2 : 1);
// if (n > maxLocals) {
// maxLocals = n;
// }
// }
// }
// 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 (compute == FRAMES) {
// // completes the control flow graph with exception handler blocks
//// Handler handler = firstHandler;
//// while (handler != null) {
//// Label l = handler.start.getFirst();
//// Label h = handler.handler.getFirst();
//// Label e = handler.end.getFirst();
//// // computes the kind of the edges to 'h'
//// String t = handler.desc == null
//// ? "java/lang/Throwable"
//// : handler.desc;
//// int kind = Frame.OBJECT | cw.addType(t);
//// // h is an exception handler
//// h.status |= Label.TARGET;
//// // adds 'h' as a successor of labels between 'start' and 'end'
//// while (l != e) {
//// // creates an edge to 'h'
//// Edge b = new Edge();
//// b.info = kind;
//// b.successor = h;
//// // adds it to the successors of 'l'
//// b.next = l.successors;
//// l.successors = b;
//// // goes to the next label
//// l = l.successor;
//// }
//// handler = handler.next;
//// }
//
// // creates and visits the first (implicit) frame
// Frame f = labels.frame;
// Type[] args = Type.getArgumentTypes(descriptor);
// f.initInputFrame(cw, access, args, this.maxLocals);
// visitFrame(f);
//
// /*
// * fix point algorithm: mark the first basic block as 'changed'
// * (i.e. put it in the 'changed' list) and, while there are changed
// * basic blocks, choose one, mark it as unchanged, and update its
// * successors (which can be changed in the process).
// */
// int max = 0;
// Label changed = labels;
// while (changed != null) {
// // removes a basic block from the list of changed basic blocks
// Label l = changed;
// changed = changed.next;
// l.next = null;
// f = l.frame;
// // a reachable jump target must be stored in the stack map
// if ((l.status & Label.TARGET) != 0) {
// l.status |= Label.STORE;
// }
// // all visited labels are reachable, by definition
// l.status |= Label.REACHABLE;
// // updates the (absolute) maximum stack size
// int blockMax = f.inputStack.length + l.outputStackMax;
// if (blockMax > max) {
// max = blockMax;
// }
// // updates the successors of the current basic block
// Edge e = l.successors;
// while (e != null) {
// Label n = e.successor.getFirst();
// boolean change = f.merge(cw, n.frame, e.info);
// if (change && n.next == null) {
// // if n has changed and is not already in the 'changed'
// // list, adds it to this list
// n.next = changed;
// changed = n;
// }
// e = e.next;
// }
// }
//
// // visits all the frames that must be stored in the stack map
// Label l = labels;
// while (l != null) {
// f = l.frame;
// if ((l.status & Label.STORE) != 0) {
// visitFrame(f);
// }
// if ((l.status & Label.REACHABLE) == 0) {
// // finds start and end of dead basic block
// Label k = l.successor;
// int start = l.position;
// int end = (k == null ? code.length : k.position) - 1;
// // if non empty basic block
// if (end >= start) {
// max = Math.max(max, 1);
// // replaces instructions with NOP ... NOP ATHROW
// for (int i = start; i < end; ++i) {
// code.data[i] = Opcodes.NOP;
// }
// code.data[end] = (byte) Opcodes.ATHROW;
// // emits a frame for this unreachable block
// startFrame(start, 0, 1);
// frame[frameIndex++] = Frame.OBJECT
// | cw.addType("java/lang/Throwable");
// endFrame();
// }
// }
// l = l.successor;
// }
//
// this.maxStack = max;
// } else
if (compute == MAXS) {
// completes the control flow graph with exception handler blocks
// Handler handler = firstHandler;
// while (handler != null) {
// Label l = handler.start;
// Label h = handler.handler;
// Label e = handler.end;
// // adds 'h' as a successor of labels between 'start' and 'end'
// while (l != e) {
// // creates an edge to 'h'
// Edge b = new Edge();
// b.info = Edge.EXCEPTION;
// b.successor = h;
// // adds it to the successors of 'l'
// if ((l.status & Label.JSR) == 0) {
// b.next = l.successors;
// l.successors = b;
// } else {
// // if l is a JSR block, adds b after the first two edges
// // to preserve the hypothesis about JSR block successors
// // order (see {@link #visitJumpInsn})
// b.next = l.successors.next.next;
// l.successors.next.next = b;
// }
// // goes to the next label
// l = l.successor;
// }
// handler = handler.next;
// }
if (subroutines > 0) {
// completes the control flow graph with the RET successors
/*
* first step: finds the subroutines. This step determines, for
* each basic block, to which subroutine(s) it belongs.
*/
// finds the basic blocks that belong to the "main" subroutine
int id = 0;
labels.visitSubroutine(null, 1, subroutines);
// finds the basic blocks that belong to the real subroutines
Label l = labels;
while (l != null) {
if ((l.status & Label.JSR) != 0) {
// the subroutine is defined by l's TARGET, not by l
Label subroutine = l.successors.next.successor;
// if this subroutine has not been visited yet...
if ((subroutine.status & Label.VISITED) == 0) {
// ...assigns it a new id and finds its basic blocks
id += 1;
subroutine.visitSubroutine(null, (id / 32L) << 32
| (1L << (id % 32)), subroutines);
}
}
l = l.successor;
}
// second step: finds the successors of RET blocks
l = labels;
while (l != null) {
if ((l.status & Label.JSR) != 0) {
Label L = labels;
while (L != null) {
L.status &= ~Label.VISITED2;
L = L.successor;
}
// the subroutine is defined by l's TARGET, not by l
Label subroutine = l.successors.next.successor;
subroutine.visitSubroutine(l, 0, subroutines);
}
l = l.successor;
}
}
/*
* 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#inputStackTop} of the
* blocks in the block stack are the true (non relative) beginning
* stack sizes of these blocks.
*/
int max = 0;
Label stack = labels;
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.inputStackTop;
int blockMax = start + l.outputStackMax;
// updates the global max stack size
if (blockMax > max) {
max = blockMax;
}
// analyzes the successors of the block
Edge b = l.successors;
if ((l.status & Label.JSR) != 0) {
// ignores the first edge of JSR blocks (virtual successor)
b = b.next;
}
while (b != null) {
l = b.successor;
// if this successor has not already been pushed...
if ((l.status & Label.PUSHED) == 0) {
// computes its true beginning stack size...
l.inputStackTop = b.info == Edge.EXCEPTION ? 1 : start
+ b.info;
// ...and pushes it onto the stack
l.status |= Label.PUSHED;
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
// ------------------------------------------------------------------------
/**
* Adds a successor to the {@link #currentBlock currentBlock} block.
*
* @param info information about the control flow edge to be added.
* @param successor the successor block to be added to the current block.
*/
private void addSuccessor(final int info, final Label successor) {
// creates and initializes an Edge object...
Edge b = new Edge();
b.info = info;
b.successor = successor;
// ...and adds it to the successor list of the currentBlock block
b.next = currentBlock.successors;
currentBlock.successors = b;
}
/**
* Ends the current basic block. This method must be used in the case where
* the current basic block does not have any successor.
*/
private void noSuccessor() {
// if (compute == FRAMES) {
// Label l = new Label();
// l.frame = new Frame();
// l.frame.owner = l;
// l.resolve(this, code.length, code.data);
// previousBlock.successor = l;
// previousBlock = l;
// } else
{
currentBlock.outputStackMax = maxStackSize;
}
currentBlock = null;
}
// ------------------------------------------------------------------------
// Utility methods: stack map frames
// ------------------------------------------------------------------------
//
// /**
// * Visits a frame that has been computed from scratch.
// *
// * @param f the frame that must be visited.
// */
// private void visitFrame(final Frame f) {
// int i, t;
// int nTop = 0;
// int nLocal = 0;
// int nStack = 0;
// int[] locals = f.inputLocals;
// int[] stacks = f.inputStack;
// // computes the number of locals (ignores TOP types that are just after
// // a LONG or a DOUBLE, and all trailing TOP types)
// for (i = 0; i < locals.length; ++i) {
// t = locals[i];
// if (t == Frame.TOP) {
// ++nTop;
// } else {
// nLocal += nTop + 1;
// nTop = 0;
// }
// if (t == Frame.LONG || t == Frame.DOUBLE) {
// ++i;
// }
// }
// // computes the stack size (ignores TOP types that are just after
// // a LONG or a DOUBLE)
// for (i = 0; i < stacks.length; ++i) {
// t = stacks[i];
// ++nStack;
// if (t == Frame.LONG || t == Frame.DOUBLE) {
// ++i;
// }
// }
// // visits the frame and its content
// startFrame(f.owner.position, nLocal, nStack);
// for (i = 0; nLocal > 0; ++i, --nLocal) {
// t = locals[i];
// frame[frameIndex++] = t;
// if (t == Frame.LONG || t == Frame.DOUBLE) {
// ++i;
// }
// }
// for (i = 0; i < stacks.length; ++i) {
// t = stacks[i];
// frame[frameIndex++] = t;
// if (t == Frame.LONG || t == Frame.DOUBLE) {
// ++i;
// }
// }
// endFrame();
// }
//
// /**
// * Starts the visit of a stack map frame.
// *
// * @param offset the offset of the instruction to which the frame
// * corresponds.
// * @param nLocal the number of local variables in the frame.
// * @param nStack the number of stack elements in the frame.
// */
// private void startFrame(final int offset, final int nLocal, final int nStack)
// {
// int n = 3 + nLocal + nStack;
// if (frame == null || frame.length < n) {
// frame = new int[n];
// }
// frame[0] = offset;
// frame[1] = nLocal;
// frame[2] = nStack;
// frameIndex = 3;
// }
//
// /**
// * Checks if the visit of the current frame {@link #frame} is finished, and
// * if yes, write it in the StackMapTable attribute.
// */
// private void endFrame() {
// if (previousFrame != null) { // do not write the first frame
// if (stackMap == null) {
// stackMap = new ByteVector();
// }
// writeFrame();
// ++frameCount;
// }
// previousFrame = frame;
// frame = null;
// }
//
// /**
// * Compress and writes the current frame {@link #frame} in the StackMapTable
// * attribute.
// */
// private void writeFrame() {
// int clocalsSize = frame[1];
// int cstackSize = frame[2];
// if ((cw.version & 0xFFFF) < Opcodes.V1_6) {
// stackMap.putShort(frame[0]).putShort(clocalsSize);
// writeFrameTypes(3, 3 + clocalsSize);
// stackMap.putShort(cstackSize);
// writeFrameTypes(3 + clocalsSize, 3 + clocalsSize + cstackSize);
// return;
// }
// int localsSize = previousFrame[1];
// int type = FULL_FRAME;
// int k = 0;
// int delta;
// if (frameCount == 0) {
// delta = frame[0];
// } else {
// delta = frame[0] - previousFrame[0] - 1;
// }
// if (cstackSize == 0) {
// k = clocalsSize - localsSize;
// switch (k) {
// case -3:
// case -2:
// case -1:
// type = CHOP_FRAME;
// localsSize = clocalsSize;
// break;
// case 0:
// type = delta < 64 ? SAME_FRAME : SAME_FRAME_EXTENDED;
// break;
// case 1:
// case 2:
// case 3:
// type = APPEND_FRAME;
// break;
// }
// } else if (clocalsSize == localsSize && cstackSize == 1) {
// type = delta < 63
// ? SAME_LOCALS_1_STACK_ITEM_FRAME
// : SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED;
// }
// if (type != FULL_FRAME) {
// // verify if locals are the same
// int l = 3;
// for (int j = 0; j < localsSize; j++) {
// if (frame[l] != previousFrame[l]) {
// type = FULL_FRAME;
// break;
// }
// l++;
// }
// }
// switch (type) {
// case SAME_FRAME:
// stackMap.putByte(delta);
// break;
// case SAME_LOCALS_1_STACK_ITEM_FRAME:
// stackMap.putByte(SAME_LOCALS_1_STACK_ITEM_FRAME + delta);
// writeFrameTypes(3 + clocalsSize, 4 + clocalsSize);
// break;
// case SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED:
// stackMap.putByte(SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED)
// .putShort(delta);
// writeFrameTypes(3 + clocalsSize, 4 + clocalsSize);
// break;
// case SAME_FRAME_EXTENDED:
// stackMap.putByte(SAME_FRAME_EXTENDED).putShort(delta);
// break;
// case CHOP_FRAME:
// stackMap.putByte(SAME_FRAME_EXTENDED + k).putShort(delta);
// break;
// case APPEND_FRAME:
// stackMap.putByte(SAME_FRAME_EXTENDED + k).putShort(delta);
// writeFrameTypes(3 + localsSize, 3 + clocalsSize);
// break;
// // case FULL_FRAME:
// default:
// stackMap.putByte(FULL_FRAME)
// .putShort(delta)
// .putShort(clocalsSize);
// writeFrameTypes(3, 3 + clocalsSize);
// stackMap.putShort(cstackSize);
// writeFrameTypes(3 + clocalsSize, 3 + clocalsSize + cstackSize);
// }
// }
//
// /**
// * Writes some types of the current frame {@link #frame} into the
// * StackMapTableAttribute. This method converts types from the format used
// * in {@link Label} to the format used in StackMapTable attributes. In
// * particular, it converts type table indexes to constant pool indexes.
// *
// * @param start index of the first type in {@link #frame} to write.
// * @param end index of last type in {@link #frame} to write (exclusive).
// */
// private void writeFrameTypes(final int start, final int end) {
// for (int i = start; i < end; ++i) {
// int t = frame[i];
// int d = t & Frame.DIM;
// if (d == 0) {
// int v = t & Frame.BASE_VALUE;
// switch (t & Frame.BASE_KIND) {
// case Frame.OBJECT:
// stackMap.putByte(7)
// .putShort(cw.newClass(cw.typeTable[v].strVal1));
// break;
// case Frame.UNINITIALIZED:
// stackMap.putByte(8).putShort(cw.typeTable[v].intVal);
// break;
// default:
// stackMap.putByte(v);
// }
// } else {
// StringBuilder buf = new StringBuilder();
// d >>= 28;
// while (d-- > 0) {
// buf.append('[');
// }
// if ((t & Frame.BASE_KIND) == Frame.OBJECT) {
// buf.append('L');
// buf.append(cw.typeTable[t & Frame.BASE_VALUE].strVal1);
// buf.append(';');
// } else {
// switch (t & 0xF) {
// case 1:
// buf.append('I');
// break;
// case 2:
// buf.append('F');
// break;
// case 3:
// buf.append('D');
// break;
// case 9:
// buf.append('Z');
// break;
// case 10:
// buf.append('B');
// break;
// case 11:
// buf.append('C');
// break;
// case 12:
// buf.append('S');
// break;
// default:
// buf.append('J');
// }
// }
// stackMap.putByte(7).putShort(cw.newClass(buf.toString()));
// }
// }
// }
// private void writeFrameType(final Object type) {
// if (type instanceof String) {
// stackMap.putByte(7).putShort(cw.newClass((String) type));
// } else if (type instanceof Integer) {
// stackMap.putByte(((Integer) type).intValue());
// } else {
// stackMap.putByte(8).putShort(((Label) type).position);
// }
// }
// ------------------------------------------------------------------------
// 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 (resize) {
// replaces the temporary jump opcodes introduced by Label.resolve.
resizeInstructions();
}
int size = 8;
if (code.length > 0) {
cw.newUTF8("Code");
size += 18 + code.length + 8 * handlerCount;
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 (stackMap != null) {
boolean zip = (cw.version & 0xFFFF) >= Opcodes.V1_6;
cw.newUTF8(zip ? "StackMapTable" : "StackMap");
size += 8 + stackMap.length;
}
}
if (exceptionCount > 0) {
cw.newUTF8("Exceptions");
size += 8 + 2 * exceptionCount;
}
if ((access & Opcodes.ACC_SYNTHETIC) != 0
&& ((cw.version & 0xFFFF) < Opcodes.V1_5 || (access & ClassWriter.ACC_SYNTHETIC_ATTRIBUTE) != 0))
{
cw.newUTF8("Synthetic");
size += 6;
}
if ((access & Opcodes.ACC_DEPRECATED) != 0) {
cw.newUTF8("Deprecated");
size += 6;
}
if (signature != null) {
cw.newUTF8("Signature");
cw.newUTF8(signature);
size += 8;
}
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) {
int mask = Opcodes.ACC_DEPRECATED
| ClassWriter.ACC_SYNTHETIC_ATTRIBUTE
| ((access & ClassWriter.ACC_SYNTHETIC_ATTRIBUTE) / (ClassWriter.ACC_SYNTHETIC_ATTRIBUTE / Opcodes.ACC_SYNTHETIC));
out.putShort(access & ~mask).putShort(name).putShort(desc);
int attributeCount = 0;
if (code.length > 0) {
++attributeCount;
}
if (exceptionCount > 0) {
++attributeCount;
}
if ((access & Opcodes.ACC_SYNTHETIC) != 0
&& ((cw.version & 0xFFFF) < Opcodes.V1_5 || (access & ClassWriter.ACC_SYNTHETIC_ATTRIBUTE) != 0))
{
++attributeCount;
}
if ((access & Opcodes.ACC_DEPRECATED) != 0) {
++attributeCount;
}
if (signature != null) {
++attributeCount;
}
out.putShort(attributeCount);
if (code.length > 0) {
int size = 12 + code.length + 8 * handlerCount;
if (localVar != null) {
size += 8 + localVar.length;
}
if (localVarType != null) {
size += 8 + localVarType.length;
}
if (lineNumber != null) {
size += 8 + lineNumber.length;
}
if (stackMap != null) {
size += 8 + stackMap.length;
}
out.putShort(cw.newUTF8("Code")).putInt(size);
out.putShort(maxStack).putShort(maxLocals);
out.putInt(code.length).putByteArray(code.data, 0, code.length);
out.putShort(handlerCount);
// if (handlerCount > 0) {
// Handler h = firstHandler;
// 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 (stackMap != null) {
++attributeCount;
}
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 (stackMap != null) {
boolean zip = (cw.version & 0xFFFF) >= Opcodes.V1_6;
out.putShort(cw.newUTF8(zip ? "StackMapTable" : "StackMap"));
out.putInt(stackMap.length + 2).putShort(frameCount);
out.putByteArray(stackMap.data, 0, stackMap.length);
}
}
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 || (access & ClassWriter.ACC_SYNTHETIC_ATTRIBUTE) != 0))
{
out.putShort(cw.newUTF8("Synthetic")).putInt(0);
}
if ((access & Opcodes.ACC_DEPRECATED) != 0) {
out.putShort(cw.newUTF8("Deprecated")).putInt(0);
}
if (signature != null) {
out.putShort(cw.newUTF8("Signature"))
.putInt(2)
.putShort(cw.newUTF8(signature));
}
}
// ------------------------------------------------------------------------
// Utility methods: instruction resizing (used to handle GOTO_W and JSR_W)
// ------------------------------------------------------------------------
/**
* Resizes and replaces the temporary instructions inserted by
* {@link Label#resolve} for wide forward jumps, 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.
*/
private void resizeInstructions() {
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[0]; // copy of indexes
int[] allSizes = new int[0]; // copy of sizes
boolean[] resize; // instructions to be resized
int newOffset; // future offset of a jump instruction
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.ITFDYNMETH_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) {
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);
newCode.putByteArray(null, 0, (4 - newCode.length % 4) % 4);
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);
newCode.putByteArray(null, 0, (4 - newCode.length % 4) % 4);
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.ITFDYNMETH_INSN:
newCode.putByteArray(b, u, 5);
u += 5;
break;
// case MANA_INSN:
default:
newCode.putByteArray(b, u, 4);
u += 4;
break;
}
}
// //recomputes the stack map frames
// if (frameCount > 0) {
// if (compute == FRAMES) {
// frameCount = 0;
// stackMap = null;
// previousFrame = null;
// frame = null;
// Frame f = new Frame();
// f.owner = labels;
// Type[] args = Type.getArgumentTypes(descriptor);
// f.initInputFrame(cw, access, args, maxLocals);
// visitFrame(f);
// Label l = labels;
// while (l != null) {
// /*
// * here we need the original label position. getNewOffset
// * must therefore never have been called for this label.
// */
// u = l.position - 3;
// if ((l.status & Label.STORE) != 0 || (u >= 0 && resize[u]))
// {
// getNewOffset(allIndexes, allSizes, l);
// // TO DO update offsets in UNINITIALIZED values
// visitFrame(l.frame);
// }
// l = l.successor;
// }
// } else
// {
// /*
// * Resizing an existing stack map frame table is really hard.
// * Not only the table must be parsed to update the offets, but
// * new frames may be needed for jump instructions that were
// * inserted by this method. And updating the offsets or
// * inserting frames can change the format of the following
// * frames, in case of packed frames. In practice the whole table
// * must be recomputed. For this the frames are marked as
// * potentially invalid. This will cause the whole class to be
// * reread and rewritten with the COMPUTE_FRAMES option (see the
// * ClassWriter.toByteArray method). This is not very efficient
// * but is much easier and requires much less code than any other
// * method I can think of.
// */
// cw.invalidFrames = true;
// }
// }
// updates the exception handler block labels
// Handler h = firstHandler;
// while (h != null) {
// getNewOffset(allIndexes, allSizes, h.start);
// getNewOffset(allIndexes, allSizes, h.end);
// getNewOffset(allIndexes, allSizes, h.handler);
// h = h.next;
// }
// updates the instructions addresses in the
// local var and line number tables
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;
}
}
// replaces old bytecodes with new ones
code = newCode;
}
/**
* 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.status & Label.RESIZED) == 0) {
label.position = getNewOffset(indexes, sizes, 0, label.position);
label.status |= Label.RESIZED;
}
}
}