factor/org/objectweb/asm/attrs/StackMapFrame.java

228 lines
7.6 KiB
Java

/**
* ASM: a very small and fast Java bytecode manipulation framework
* Copyright (c) 2000,2002,2003 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.
*
* Contact: Eric.Bruneton@rd.francetelecom.com
*
* Author: Eric Bruneton
*/
package org.objectweb.asm.attrs;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.objectweb.asm.ByteVector;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Label;
/**
* StackMapFrame is used by {@link StackMapAttribute} to hold state of the stack
* and local variables for a single execution branch.
*
* <i>Note that Long and Double types are represented by two entries in locals
* and stack. Second entry sohould be always of type Top.</i>
*
* @see <a href="http://www.jcp.org/en/jsr/detail?id=139">JSR 139 : Connected
* Limited Device Configuration 1.1</a>
*
* @author Eugene Kuleshov
*/
public class StackMapFrame {
public Label label;
public List locals = new LinkedList();
public List stack = new LinkedList();
public int read (ClassReader cr,
int off, char[] buf, int codeOff, Label[] labels) {
int n = cr.readUnsignedShort(off);
off += 2;
if (labels[n] == null) {
labels[n] = new Label();
}
label = labels[n];
off = readTypeInfo(cr, off, locals, labels, buf,
cr.readUnsignedShort(codeOff + 2)); // maxLocals
off = readTypeInfo(cr, off, stack, labels, buf,
cr.readUnsignedShort(codeOff)); // maxStack
return off;
}
public void write (ClassWriter cw,
int maxStack, int maxLocals, ByteVector bv) {
bv.putShort(label.getOffset());
writeTypeInfo(bv, cw, locals, maxLocals);
writeTypeInfo(bv, cw, stack, maxStack);
}
public void getLabels (Set labels) {
labels.add(label);
getTypeInfoLabels(labels, locals);
getTypeInfoLabels(labels, stack);
}
private void getTypeInfoLabels (Set labels, List info) {
for (Iterator it = info.iterator(); it.hasNext();) {
StackMapType typeInfo = (StackMapType)it.next();
if (typeInfo.getType() == StackMapType.ITEM_Uninitialized) {
labels.add(typeInfo.getLabel());
}
}
}
private int readTypeInfo (ClassReader cr, int off,
List info, Label[] labels, char[] buf, int max) {
int n = 0;
if (max > StackMapAttribute.MAX_SIZE) {
n = cr.readInt(off);
off += 4;
} else {
n = cr.readUnsignedShort(off);
off += 2;
}
for (int j = 0; j < n; j++) {
int itemType = cr.readByte(off++);
StackMapType typeInfo = StackMapType.getTypeInfo(itemType);
info.add(typeInfo);
switch (itemType) {
case StackMapType.ITEM_Long: //
case StackMapType.ITEM_Double: //
info.add(StackMapType.getTypeInfo(StackMapType.ITEM_Top));
break;
case StackMapType.ITEM_Object: //
typeInfo.setObject(cr.readClass(off, buf));
off += 2;
break;
case StackMapType.ITEM_Uninitialized: //
int o = cr.readUnsignedShort(off);
off += 2;
if (labels[o] == null) {
labels[o] = new Label();
}
typeInfo.setLabel(labels[o]);
break;
}
}
return off;
}
private void writeTypeInfo (ByteVector bv,
ClassWriter cw, List info, int max) {
if (max > StackMapAttribute.MAX_SIZE) {
bv.putInt(info.size());
} else {
bv.putShort(info.size());
}
for (int j = 0; j < info.size(); j++) {
StackMapType typeInfo = (StackMapType)info.get(j);
bv = new ByteVector().putByte(typeInfo.getType());
switch (typeInfo.getType()) {
case StackMapType.ITEM_Long: //
case StackMapType.ITEM_Double: //
// skip Top in the stack/locals after long/double
j++;
break;
case StackMapType.ITEM_Object: //
bv.putShort(cw.newClass(typeInfo.getObject()));
break;
case StackMapType.ITEM_Uninitialized: //
bv.putShort(typeInfo.getLabel().getOffset());
break;
}
}
}
public void dump (StringBuffer buf, String varName, Map labelNames) {
declareLabel(buf, labelNames, label);
buf.append(varName).append(".label = ")
.append(labelNames.get(label)).append(";\n");
dumpTypeInfo(buf, varName, labelNames, locals);
dumpTypeInfo(buf, varName, labelNames, stack);
}
private void dumpTypeInfo (StringBuffer buf,
String varName, Map labelNames, List infos) {
if (infos.size() > 0) {
buf.append("{\n");
for (int i = 0; i < infos.size(); i++) {
StackMapType typeInfo = (StackMapType)infos.get(i);
String localName = varName + "Info" + i;
int type = typeInfo.getType();
buf.append("StackMapType ").append(localName)
.append(" = new StackMapType( StackMapType.ITEM_")
.append(StackMapType.ITEM_NAMES[type]).append(");\n");
switch (type) {
case StackMapType.ITEM_Object: //
buf.append(localName).append(".setObject(")
.append(typeInfo.getObject()).append(");\n");
break;
case StackMapType.ITEM_Uninitialized: //
declareLabel(buf, labelNames, typeInfo.getLabel());
buf.append(localName).append(".setLabel(")
.append(labelNames.get(typeInfo.getLabel())).append(");\n");
break;
}
buf.append(varName).append(".add(").append(localName).append(");\n");
}
buf.append("}\n");
}
}
public static void declareLabel (StringBuffer buf, Map labelNames, Label l) {
String name = (String)labelNames.get(l);
if (name == null) {
name = "l" + labelNames.size();
labelNames.put(l, name);
buf.append("Label ").append(name).append(" = new Label();\n");
}
}
public String toString () {
StringBuffer sb = new StringBuffer("Frame:L");
sb.append(System.identityHashCode(label));
sb.append(" locals").append(locals);
sb.append(" stack").append(stack);
return sb.toString();
}
}