2.4/dev/core/src/com/google/gwt/dev/asm/commons/LocalVariablesSorter.java - gwt - Git at Google

 /***
  * 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 com.google.gwt.dev.asm.commons;

 import com.google.gwt.dev.asm.Label;
 import com.google.gwt.dev.asm.MethodAdapter;
 import com.google.gwt.dev.asm.MethodVisitor;
 import com.google.gwt.dev.asm.Opcodes;
 import com.google.gwt.dev.asm.Type;

 /**
  * A {@link MethodAdapter} that renumbers local variables in their order of
  * appearance. This adapter allows one to easily add new local variables to a
  * method. It may be used by inheriting from this class, but the preferred way
  * of using it is via delegation: the next visitor in the chain can indeed add
  * new locals when needed by calling {@link #newLocal} on this adapter (this
  * requires a reference back to this {@link LocalVariablesSorter}).
  *
  * @author Chris Nokleberg
  * @author Eugene Kuleshov
  * @author Eric Bruneton
  */
 public class LocalVariablesSorter extends MethodAdapter {

     private static final Type OBJECT_TYPE = Type.getObjectType("java/lang/Object");

     /**
      * Mapping from old to new local variable indexes. A local variable at index
      * i of size 1 is remapped to 'mapping[2*i]', while a local variable at
      * index i of size 2 is remapped to 'mapping[2*i+1]'.
      */
     private int[] mapping = new int[40];

     /**
      * Array used to store stack map local variable types after remapping.
      */
     private Object[] newLocals = new Object[20];

     /**
      * Index of the first local variable, after formal parameters.
      */
     protected final int firstLocal;

     /**
      * Index of the next local variable to be created by {@link #newLocal}.
      */
     protected int nextLocal;

     /**
      * Indicates if at least one local variable has moved due to remapping.
      */
     private boolean changed;

     /**
      * Creates a new {@link LocalVariablesSorter}.
      *
      * @param access access flags of the adapted method.
      * @param desc the method's descriptor (see {@link Type Type}).
      * @param mv the method visitor to which this adapter delegates calls.
      */
     public LocalVariablesSorter(
         final int access,
         final String desc,
         final MethodVisitor mv)
     {
         super(mv);
         Type[] args = Type.getArgumentTypes(desc);
         nextLocal = (Opcodes.ACC_STATIC & access) == 0 ? 1 : 0;
         for (int i = 0; i < args.length; i++) {
             nextLocal += args[i].getSize();
         }
         firstLocal = nextLocal;
     }

     public void visitVarInsn(final int opcode, final int var) {
         Type type;
         switch (opcode) {
             case Opcodes.LLOAD:
             case Opcodes.LSTORE:
                 type = Type.LONG_TYPE;
                 break;

             case Opcodes.DLOAD:
             case Opcodes.DSTORE:
                 type = Type.DOUBLE_TYPE;
                 break;

             case Opcodes.FLOAD:
             case Opcodes.FSTORE:
                 type = Type.FLOAT_TYPE;
                 break;

             case Opcodes.ILOAD:
             case Opcodes.ISTORE:
                 type = Type.INT_TYPE;
                 break;

             case Opcodes.ALOAD:
             case Opcodes.ASTORE:
                 type = OBJECT_TYPE;
                 break;

             // case RET:
             default:
                 type = Type.VOID_TYPE;
         }
         mv.visitVarInsn(opcode, remap(var, type));
     }

     public void visitIincInsn(final int var, final int increment) {
         mv.visitIincInsn(remap(var, Type.INT_TYPE), increment);
     }

     public void visitMaxs(final int maxStack, final int maxLocals) {
         mv.visitMaxs(maxStack, nextLocal);
     }

     public void visitLocalVariable(
         final String name,
         final String desc,
         final String signature,
         final Label start,
         final Label end,
         final int index)
     {
         int newIndex = remap(index, Type.getType(desc));
         mv.visitLocalVariable(name, desc, signature, start, end, newIndex);
     }

     public void visitFrame(
         final int type,
         final int nLocal,
         final Object[] local,
         final int nStack,
         final Object[] stack)
     {
         if (type != Opcodes.F_NEW) { // uncompressed frame
             throw new IllegalStateException("ClassReader.accept() should be called with EXPAND_FRAMES flag");
         }

         if (!changed) { // optimization for the case where mapping = identity
             mv.visitFrame(type, nLocal, local, nStack, stack);
             return;
         }

         // creates a copy of newLocals
         Object[] oldLocals = new Object[newLocals.length];
         System.arraycopy(newLocals, 0, oldLocals, 0, oldLocals.length);

         // copies types from 'local' to 'newLocals'
         // 'newLocals' already contains the variables added with 'newLocal'

         int index = 0; // old local variable index
         int number = 0; // old local variable number
         for (; number < nLocal; ++number) {
             Object t = local[number];
             int size = t == Opcodes.LONG || t == Opcodes.DOUBLE ? 2 : 1;
             if (t != Opcodes.TOP) {
                 setFrameLocal(remap(index, size), t);
             }
             index += size;
         }

         // removes TOP after long and double types as well as trailing TOPs

         index = 0;
         number = 0;
         for (int i = 0; index < newLocals.length; ++i) {
             Object t = newLocals[index++];
             if (t != null && t != Opcodes.TOP) {
                 newLocals[i] = t;
                 number = i + 1;
                 if (t == Opcodes.LONG || t == Opcodes.DOUBLE) {
                     index += 1;
                 }
             } else {
                 newLocals[i] = Opcodes.TOP;
             }
         }

         // visits remapped frame
         mv.visitFrame(type, number, newLocals, nStack, stack);

         // restores original value of 'newLocals'
         newLocals = oldLocals;
     }

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

     /**
      * Creates a new local variable of the given type.
      *
      * @param type the type of the local variable to be created.
      * @return the identifier of the newly created local variable.
      */
     public int newLocal(final Type type) {
         Object t;
         switch (type.getSort()) {
             case Type.BOOLEAN:
             case Type.CHAR:
             case Type.BYTE:
             case Type.SHORT:
             case Type.INT:
                 t = Opcodes.INTEGER;
                 break;
             case Type.FLOAT:
                 t = Opcodes.FLOAT;
                 break;
             case Type.LONG:
                 t = Opcodes.LONG;
                 break;
             case Type.DOUBLE:
                 t = Opcodes.DOUBLE;
                 break;
             case Type.ARRAY:
                 t = type.getDescriptor();
                 break;
             // case Type.OBJECT:
             default:
                 t = type.getInternalName();
                 break;
         }
         int local = nextLocal;
         nextLocal += type.getSize();
         setLocalType(local, type);
         setFrameLocal(local, t);
         return local;
     }

     /**
      * Sets the current type of the given local variable. The default
      * implementation of this method does nothing.
      *
      * @param local a local variable identifier, as returned by {@link #newLocal
      *        newLocal()}.
      * @param type the type of the value being stored in the local variable
      */
     protected void setLocalType(final int local, final Type type) {
     }

     private void setFrameLocal(final int local, final Object type) {
         int l = newLocals.length;
         if (local >= l) {
             Object[] a = new Object[Math.max(2 * l, local + 1)];
             System.arraycopy(newLocals, 0, a, 0, l);
             newLocals = a;
         }
         newLocals[local] = type;
     }

     private int remap(final int var, final Type type) {
         if (var < firstLocal) {
             return var;
         }
         int key = 2 * var + type.getSize() - 1;
         int size = mapping.length;
         if (key >= size) {
             int[] newMapping = new int[Math.max(2 * size, key + 1)];
             System.arraycopy(mapping, 0, newMapping, 0, size);
             mapping = newMapping;
         }
         int value = mapping[key];
         if (value == 0) {
             value = newLocalMapping(type);
             setLocalType(value, type);
             mapping[key] = value + 1;
         } else {
             value--;
         }
         if (value != var) {
             changed = true;
         }
         return value;
     }

     protected int newLocalMapping(final Type type) {
         int local = nextLocal;
         nextLocal += type.getSize();
         return local;
     }

     private int remap(final int var, final int size) {
         if (var < firstLocal || !changed) {
             return var;
         }
         int key = 2 * var + size - 1;
         int value = key < mapping.length ? mapping[key] : 0;
         if (value == 0) {
             throw new IllegalStateException("Unknown local variable " + var);
         }
         return value - 1;
     }
 }
	/***
	* 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 com.google.gwt.dev.asm.commons;

	import com.google.gwt.dev.asm.Label;
	import com.google.gwt.dev.asm.MethodAdapter;
	import com.google.gwt.dev.asm.MethodVisitor;
	import com.google.gwt.dev.asm.Opcodes;
	import com.google.gwt.dev.asm.Type;

	/**
	* A {@link MethodAdapter} that renumbers local variables in their order of
	* appearance. This adapter allows one to easily add new local variables to a
	* method. It may be used by inheriting from this class, but the preferred way
	* of using it is via delegation: the next visitor in the chain can indeed add
	* new locals when needed by calling {@link #newLocal} on this adapter (this
	* requires a reference back to this {@link LocalVariablesSorter}).
	*
	* @author Chris Nokleberg
	* @author Eugene Kuleshov
	* @author Eric Bruneton
	*/
	public class LocalVariablesSorter extends MethodAdapter {

	private static final Type OBJECT_TYPE = Type.getObjectType("java/lang/Object");

	/**
	* Mapping from old to new local variable indexes. A local variable at index
	* i of size 1 is remapped to 'mapping[2*i]', while a local variable at
	* index i of size 2 is remapped to 'mapping[2*i+1]'.
	*/
	private int[] mapping = new int[40];

	/**
	* Array used to store stack map local variable types after remapping.
	*/
	private Object[] newLocals = new Object[20];

	/**
	* Index of the first local variable, after formal parameters.
	*/
	protected final int firstLocal;

	/**
	* Index of the next local variable to be created by {@link #newLocal}.
	*/
	protected int nextLocal;

	/**
	* Indicates if at least one local variable has moved due to remapping.
	*/
	private boolean changed;

	/**
	* Creates a new {@link LocalVariablesSorter}.
	*
	* @param access access flags of the adapted method.
	* @param desc the method's descriptor (see {@link Type Type}).
	* @param mv the method visitor to which this adapter delegates calls.
	*/
	public LocalVariablesSorter(
	final int access,
	final String desc,
	final MethodVisitor mv)
	{
	super(mv);
	Type[] args = Type.getArgumentTypes(desc);
	nextLocal = (Opcodes.ACC_STATIC & access) == 0 ? 1 : 0;
	for (int i = 0; i < args.length; i++) {
	nextLocal += args[i].getSize();
	}
	firstLocal = nextLocal;
	}

	public void visitVarInsn(final int opcode, final int var) {
	Type type;
	switch (opcode) {
	case Opcodes.LLOAD:
	case Opcodes.LSTORE:
	type = Type.LONG_TYPE;
	break;

	case Opcodes.DLOAD:
	case Opcodes.DSTORE:
	type = Type.DOUBLE_TYPE;
	break;

	case Opcodes.FLOAD:
	case Opcodes.FSTORE:
	type = Type.FLOAT_TYPE;
	break;

	case Opcodes.ILOAD:
	case Opcodes.ISTORE:
	type = Type.INT_TYPE;
	break;

	case Opcodes.ALOAD:
	case Opcodes.ASTORE:
	type = OBJECT_TYPE;
	break;

	// case RET:
	default:
	type = Type.VOID_TYPE;
	}
	mv.visitVarInsn(opcode, remap(var, type));
	}

	public void visitIincInsn(final int var, final int increment) {
	mv.visitIincInsn(remap(var, Type.INT_TYPE), increment);
	}

	public void visitMaxs(final int maxStack, final int maxLocals) {
	mv.visitMaxs(maxStack, nextLocal);
	}

	public void visitLocalVariable(
	final String name,
	final String desc,
	final String signature,
	final Label start,
	final Label end,
	final int index)
	{
	int newIndex = remap(index, Type.getType(desc));
	mv.visitLocalVariable(name, desc, signature, start, end, newIndex);
	}

	public void visitFrame(
	final int type,
	final int nLocal,
	final Object[] local,
	final int nStack,
	final Object[] stack)
	{
	if (type != Opcodes.F_NEW) { // uncompressed frame
	throw new IllegalStateException("ClassReader.accept() should be called with EXPAND_FRAMES flag");
	}

	if (!changed) { // optimization for the case where mapping = identity
	mv.visitFrame(type, nLocal, local, nStack, stack);
	return;
	}

	// creates a copy of newLocals
	Object[] oldLocals = new Object[newLocals.length];
	System.arraycopy(newLocals, 0, oldLocals, 0, oldLocals.length);

	// copies types from 'local' to 'newLocals'
	// 'newLocals' already contains the variables added with 'newLocal'

	int index = 0; // old local variable index
	int number = 0; // old local variable number
	for (; number < nLocal; ++number) {
	Object t = local[number];
	int size = t == Opcodes.LONG \|\| t == Opcodes.DOUBLE ? 2 : 1;
	if (t != Opcodes.TOP) {
	setFrameLocal(remap(index, size), t);
	}
	index += size;
	}

	// removes TOP after long and double types as well as trailing TOPs

	index = 0;
	number = 0;
	for (int i = 0; index < newLocals.length; ++i) {
	Object t = newLocals[index++];
	if (t != null && t != Opcodes.TOP) {
	newLocals[i] = t;
	number = i + 1;
	if (t == Opcodes.LONG \|\| t == Opcodes.DOUBLE) {
	index += 1;
	}
	} else {
	newLocals[i] = Opcodes.TOP;
	}
	}

	// visits remapped frame
	mv.visitFrame(type, number, newLocals, nStack, stack);

	// restores original value of 'newLocals'
	newLocals = oldLocals;
	}

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

	/**
	* Creates a new local variable of the given type.
	*
	* @param type the type of the local variable to be created.
	* @return the identifier of the newly created local variable.
	*/
	public int newLocal(final Type type) {
	Object t;
	switch (type.getSort()) {
	case Type.BOOLEAN:
	case Type.CHAR:
	case Type.BYTE:
	case Type.SHORT:
	case Type.INT:
	t = Opcodes.INTEGER;
	break;
	case Type.FLOAT:
	t = Opcodes.FLOAT;
	break;
	case Type.LONG:
	t = Opcodes.LONG;
	break;
	case Type.DOUBLE:
	t = Opcodes.DOUBLE;
	break;
	case Type.ARRAY:
	t = type.getDescriptor();
	break;
	// case Type.OBJECT:
	default:
	t = type.getInternalName();
	break;
	}
	int local = nextLocal;
	nextLocal += type.getSize();
	setLocalType(local, type);
	setFrameLocal(local, t);
	return local;
	}

	/**
	* Sets the current type of the given local variable. The default
	* implementation of this method does nothing.
	*
	* @param local a local variable identifier, as returned by {@link #newLocal
	* newLocal()}.
	* @param type the type of the value being stored in the local variable
	*/
	protected void setLocalType(final int local, final Type type) {
	}

	private void setFrameLocal(final int local, final Object type) {
	int l = newLocals.length;
	if (local >= l) {
	Object[] a = new Object[Math.max(2 * l, local + 1)];
	System.arraycopy(newLocals, 0, a, 0, l);
	newLocals = a;
	}
	newLocals[local] = type;
	}

	private int remap(final int var, final Type type) {
	if (var < firstLocal) {
	return var;
	}
	int key = 2 * var + type.getSize() - 1;
	int size = mapping.length;
	if (key >= size) {
	int[] newMapping = new int[Math.max(2 * size, key + 1)];
	System.arraycopy(mapping, 0, newMapping, 0, size);
	mapping = newMapping;
	}
	int value = mapping[key];
	if (value == 0) {
	value = newLocalMapping(type);
	setLocalType(value, type);
	mapping[key] = value + 1;
	} else {
	value--;
	}
	if (value != var) {
	changed = true;
	}
	return value;
	}

	protected int newLocalMapping(final Type type) {
	int local = nextLocal;
	nextLocal += type.getSize();
	return local;
	}

	private int remap(final int var, final int size) {
	if (var < firstLocal \|\| !changed) {
	return var;
	}
	int key = 2 * var + size - 1;
	int value = key < mapping.length ? mapping[key] : 0;
	if (value == 0) {
	throw new IllegalStateException("Unknown local variable " + var);
	}
	return value - 1;
	}
	}