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Eclipse Compiler for Java(TM)
/*******************************************************************************
* Copyright (c) 2005, 2010 IBM Corporation and others.
*
* This program and the accompanying materials
* are made available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-2.0/
*
* SPDX-License-Identifier: EPL-2.0
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.internal.compiler.codegen;
import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Map;
import org.eclipse.jdt.internal.compiler.lookup.Scope;
import org.eclipse.jdt.internal.compiler.lookup.TypeIds;
public class StackMapFrame {
public static final int USED = 1;
public static final int SAME_FRAME = 0;
public static final int CHOP_FRAME = 1;
public static final int APPEND_FRAME = 2;
public static final int SAME_FRAME_EXTENDED = 3;
public static final int FULL_FRAME = 4;
public static final int SAME_LOCALS_1_STACK_ITEMS = 5;
public static final int SAME_LOCALS_1_STACK_ITEMS_EXTENDED = 6;
public int pc;
public int numberOfStackItems;
private int numberOfLocals;
public int localIndex;
public VerificationTypeInfo[] locals;
public VerificationTypeInfo[] stackItems;
private int numberOfDifferentLocals = -1;
public int tagBits;
public StackMapFrame(int initialLocalSize) {
this.locals = new VerificationTypeInfo[initialLocalSize];
this.numberOfLocals = -1;
this.numberOfDifferentLocals = -1;
}
public int getFrameType(StackMapFrame prevFrame) {
final int offsetDelta = getOffsetDelta(prevFrame);
switch (this.numberOfStackItems) {
case 0:
switch (numberOfDifferentLocals(prevFrame)) {
case 0:
return offsetDelta <= 63 ? SAME_FRAME : SAME_FRAME_EXTENDED;
case 1:
case 2:
case 3:
return APPEND_FRAME;
case -1:
case -2:
case -3:
return CHOP_FRAME;
}
break;
case 1:
switch (numberOfDifferentLocals(prevFrame)) {
case 0:
return offsetDelta <= 63 ? SAME_LOCALS_1_STACK_ITEMS : SAME_LOCALS_1_STACK_ITEMS_EXTENDED;
}
}
return FULL_FRAME;
}
public void addLocal(int resolvedPosition, VerificationTypeInfo info) {
if (this.locals == null) {
this.locals = new VerificationTypeInfo[resolvedPosition + 1];
this.locals[resolvedPosition] = info;
} else {
final int length = this.locals.length;
if (resolvedPosition >= length) {
System.arraycopy(this.locals, 0, this.locals = new VerificationTypeInfo[resolvedPosition + 1], 0,
length);
}
this.locals[resolvedPosition] = info;
}
}
public void addStackItem(VerificationTypeInfo info) {
if (info == null) {
throw new IllegalArgumentException("info cannot be null"); //$NON-NLS-1$
}
if (this.stackItems == null) {
this.stackItems = new VerificationTypeInfo[1];
this.stackItems[0] = info;
this.numberOfStackItems = 1;
} else {
final int length = this.stackItems.length;
if (this.numberOfStackItems == length) {
System.arraycopy(this.stackItems, 0, this.stackItems = new VerificationTypeInfo[length + 1], 0, length);
}
this.stackItems[this.numberOfStackItems++] = info;
}
}
public StackMapFrame duplicate() {
Map cache = new HashMap();
int length = this.locals.length;
StackMapFrame result = new StackMapFrame(length);
result.numberOfLocals = -1;
result.numberOfDifferentLocals = -1;
result.pc = this.pc;
result.numberOfStackItems = this.numberOfStackItems;
if (length != 0) {
result.locals = new VerificationTypeInfo[length];
for (int i = 0; i < length; i++) {
final VerificationTypeInfo verificationTypeInfo = this.locals[i];
result.locals[i] = getCachedValue(cache, verificationTypeInfo);
}
}
length = this.numberOfStackItems;
if (length != 0) {
result.stackItems = new VerificationTypeInfo[length];
for (int i = 0; i < length; i++) {
final VerificationTypeInfo verificationTypeInfo = this.stackItems[i];
result.stackItems[i] = getCachedValue(cache, verificationTypeInfo);
}
}
return result;
}
private static VerificationTypeInfo getCachedValue(Map cache, VerificationTypeInfo value) {
VerificationTypeInfo cachedValue = value;
if (value != null) {
if (value.tag == VerificationTypeInfo.ITEM_UNINITIALIZED || value.tag == VerificationTypeInfo.ITEM_UNINITIALIZED_THIS) {
// we use the cache only for uninitialized info
cachedValue = cache.get(value);
if (cachedValue == null) {
cachedValue = value.duplicate();
cache.put(value, cachedValue);
}
} else {
cachedValue = value.duplicate();
}
}
return cachedValue;
}
public int numberOfDifferentLocals(StackMapFrame prevFrame) {
if (this.numberOfDifferentLocals != -1)
return this.numberOfDifferentLocals;
if (prevFrame == null) {
this.numberOfDifferentLocals = 0;
return 0;
}
VerificationTypeInfo[] prevLocals = prevFrame.locals;
VerificationTypeInfo[] currentLocals = this.locals;
int prevLocalsLength = prevLocals == null ? 0 : prevLocals.length;
int currentLocalsLength = currentLocals == null ? 0 : currentLocals.length;
int prevNumberOfLocals = prevFrame.getNumberOfLocals();
int currentNumberOfLocals = getNumberOfLocals();
int result = 0;
if (prevNumberOfLocals == 0) {
if (currentNumberOfLocals != 0) {
// need to check if there is a hole in the locals
result = currentNumberOfLocals; // append if no hole and currentNumberOfLocals <= 3
int counter = 0;
for (int i = 0; i < currentLocalsLength && counter < currentNumberOfLocals; i++) {
if (currentLocals[i] != null) {
switch (currentLocals[i].id()) {
case TypeIds.T_double:
case TypeIds.T_long:
i++;
}
counter++;
} else {
result = Integer.MAX_VALUE;
this.numberOfDifferentLocals = result;
return result;
}
}
}
} else if (currentNumberOfLocals == 0) {
// need to check if there is a hole in the prev locals
int counter = 0;
result = -prevNumberOfLocals; // chop frame if no hole and prevNumberOfLocals <= 3
for (int i = 0; i < prevLocalsLength && counter < prevNumberOfLocals; i++) {
if (prevLocals[i] != null) {
switch (prevLocals[i].id()) {
case TypeIds.T_double:
case TypeIds.T_long:
i++;
}
counter++;
} else {
result = Integer.MAX_VALUE;
this.numberOfDifferentLocals = result;
return result;
}
}
} else {
// need to see if prevLocals matches with currentLocals
int indexInPrevLocals = 0;
int indexInCurrentLocals = 0;
int currentLocalsCounter = 0;
int prevLocalsCounter = 0;
currentLocalsLoop: for (; indexInCurrentLocals < currentLocalsLength
&& currentLocalsCounter < currentNumberOfLocals; indexInCurrentLocals++) {
VerificationTypeInfo currentLocal = currentLocals[indexInCurrentLocals];
if (currentLocal != null) {
currentLocalsCounter++;
switch (currentLocal.id()) {
case TypeIds.T_double:
case TypeIds.T_long:
indexInCurrentLocals++; // next entry is null
}
}
if (indexInPrevLocals < prevLocalsLength && prevLocalsCounter < prevNumberOfLocals) {
VerificationTypeInfo prevLocal = prevLocals[indexInPrevLocals];
if (prevLocal != null) {
prevLocalsCounter++;
switch (prevLocal.id()) {
case TypeIds.T_double:
case TypeIds.T_long:
indexInPrevLocals++; // next entry is null
}
}
// now we need to check if prevLocal matches with currentLocal
// the index must be the same
if (equals(prevLocal, currentLocal) && indexInPrevLocals == indexInCurrentLocals) {
if (result != 0) {
result = Integer.MAX_VALUE;
this.numberOfDifferentLocals = result;
return result;
}
} else {
// locals at the same location are not equals - this has to be a full frame
result = Integer.MAX_VALUE;
this.numberOfDifferentLocals = result;
return result;
}
indexInPrevLocals++;
continue currentLocalsLoop;
}
// process remaining current locals
if (currentLocal != null) {
result++;
} else {
result = Integer.MAX_VALUE;
this.numberOfDifferentLocals = result;
return result;
}
indexInCurrentLocals++;
break currentLocalsLoop;
}
if (currentLocalsCounter < currentNumberOfLocals) {
for (; indexInCurrentLocals < currentLocalsLength
&& currentLocalsCounter < currentNumberOfLocals; indexInCurrentLocals++) {
VerificationTypeInfo currentLocal = currentLocals[indexInCurrentLocals];
if (currentLocal == null) {
result = Integer.MAX_VALUE;
this.numberOfDifferentLocals = result;
return result;
}
result++;
currentLocalsCounter++;
switch (currentLocal.id()) {
case TypeIds.T_double:
case TypeIds.T_long:
indexInCurrentLocals++; // next entry is null
}
}
} else if (prevLocalsCounter < prevNumberOfLocals) {
result = -result;
// process possible remaining prev locals
for (; indexInPrevLocals < prevLocalsLength
&& prevLocalsCounter < prevNumberOfLocals; indexInPrevLocals++) {
VerificationTypeInfo prevLocal = prevLocals[indexInPrevLocals];
if (prevLocal == null) {
result = Integer.MAX_VALUE;
this.numberOfDifferentLocals = result;
return result;
}
result--;
prevLocalsCounter++;
switch (prevLocal.id()) {
case TypeIds.T_double:
case TypeIds.T_long:
indexInPrevLocals++; // next entry is null
}
}
}
}
this.numberOfDifferentLocals = result;
return result;
}
public int getNumberOfLocals() {
if (this.numberOfLocals != -1) {
return this.numberOfLocals;
}
int result = 0;
final int length = this.locals == null ? 0 : this.locals.length;
for (int i = 0; i < length; i++) {
if (this.locals[i] != null) {
switch (this.locals[i].id()) {
case TypeIds.T_double:
case TypeIds.T_long:
i++;
}
result++;
}
}
this.numberOfLocals = result;
return result;
}
public int getOffsetDelta(StackMapFrame prevFrame) {
if (prevFrame == null)
return this.pc;
return prevFrame.pc == -1 ? this.pc : this.pc - prevFrame.pc - 1;
}
@Override
public String toString() {
StringBuffer buffer = new StringBuffer();
printFrame(buffer, this);
return String.valueOf(buffer);
}
private void printFrame(StringBuffer buffer, StackMapFrame frame) {
String pattern = "[pc : {0} locals: {1} stack items: {2}\nlocals: {3}\nstack: {4}\n]"; //$NON-NLS-1$
int localsLength = frame.locals == null ? 0 : frame.locals.length;
buffer.append(MessageFormat.format(pattern,
new Object[] { Integer.toString(frame.pc), Integer.toString(frame.getNumberOfLocals()),
Integer.toString(frame.numberOfStackItems), print(frame.locals, localsLength),
print(frame.stackItems, frame.numberOfStackItems) }));
}
private String print(VerificationTypeInfo[] infos, int length) {
StringBuffer buffer = new StringBuffer();
buffer.append('[');
if (infos != null) {
for (int i = 0; i < length; i++) {
if (i != 0)
buffer.append(',');
VerificationTypeInfo verificationTypeInfo = infos[i];
if (verificationTypeInfo == null) {
buffer.append("top"); //$NON-NLS-1$
continue;
}
buffer.append(verificationTypeInfo);
}
}
buffer.append(']');
return String.valueOf(buffer);
}
public void putLocal(int resolvedPosition, VerificationTypeInfo info) {
if (this.locals == null) {
this.locals = new VerificationTypeInfo[resolvedPosition + 1];
this.locals[resolvedPosition] = info;
} else {
final int length = this.locals.length;
if (resolvedPosition >= length) {
System.arraycopy(this.locals, 0, this.locals = new VerificationTypeInfo[resolvedPosition + 1], 0,
length);
}
this.locals[resolvedPosition] = info;
}
}
public void replaceWithElementType() {
VerificationTypeInfo info = this.stackItems[this.numberOfStackItems - 1];
VerificationTypeInfo info2 = info.duplicate();
info2.replaceWithElementType();
this.stackItems[this.numberOfStackItems - 1] = info2;
}
public int getIndexOfDifferentLocals(int differentLocalsCount) {
for (int i = this.locals.length - 1; i >= 0; i--) {
VerificationTypeInfo currentLocal = this.locals[i];
if (currentLocal == null) {
// check the previous slot
continue;
} else {
differentLocalsCount--;
}
if (differentLocalsCount == 0) {
return i;
}
}
return 0;
}
private static boolean equals(VerificationTypeInfo info, VerificationTypeInfo info2) {
if (info == null) {
return info2 == null;
}
if (info2 == null)
return false;
return info.equals(info2);
}
public StackMapFrame merge(StackMapFrame frame, Scope scope) {
if (frame.pc == -1) {
// branching
return this;
}
if (this.numberOfStackItems == frame.numberOfStackItems) {
for (int i = 0, max = this.numberOfStackItems; i < max; i++) {
this.stackItems[i] = this.stackItems[i].merge(frame.stackItems[i], scope);
}
}
return this;
}
}