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Utilities for ASM, a very small and fast Java bytecode manipulation framework
/***
* ASM: a very small and fast Java bytecode manipulation framework
* Copyright (c) 2000-2011 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 org.objectweb.asm.tree.analysis;
import java.util.ArrayList;
import java.util.List;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.IincInsnNode;
import org.objectweb.asm.tree.InvokeDynamicInsnNode;
import org.objectweb.asm.tree.MethodInsnNode;
import org.objectweb.asm.tree.MultiANewArrayInsnNode;
import org.objectweb.asm.tree.VarInsnNode;
/**
* A symbolic execution stack frame. A stack frame contains a set of local
* variable slots, and an operand stack. Warning: long and double values are
* represented by two slots in local variables, and by one slot in
* the operand stack.
*
* @param
* type of the Value used for the analysis.
*
* @author Eric Bruneton
*/
public class Frame {
/**
* The expected return type of the analyzed method, or null if the
* method returns void.
*/
private V returnValue;
/**
* The local variables and operand stack of this frame.
*/
private V[] values;
/**
* The number of local variables of this frame.
*/
private int locals;
/**
* The number of elements in the operand stack.
*/
private int top;
/**
* Constructs a new frame with the given size.
*
* @param nLocals
* the maximum number of local variables of the frame.
* @param nStack
* the maximum stack size of the frame.
*/
@SuppressWarnings("unchecked")
public Frame(final int nLocals, final int nStack) {
this.values = (V[]) new Value[nLocals + nStack];
this.locals = nLocals;
}
/**
* Constructs a new frame that is identical to the given frame.
*
* @param src
* a frame.
*/
public Frame(final Frame src) {
this(src.locals, src.values.length - src.locals);
init(src);
}
/**
* Copies the state of the given frame into this frame.
*
* @param src
* a frame.
* @return this frame.
*/
public Frame init(final Frame src) {
returnValue = src.returnValue;
System.arraycopy(src.values, 0, values, 0, values.length);
top = src.top;
return this;
}
/**
* Sets the expected return type of the analyzed method.
*
* @param v
* the expected return type of the analyzed method, or
* null if the method returns void.
*/
public void setReturn(final V v) {
returnValue = v;
}
/**
* Returns the maximum number of local variables of this frame.
*
* @return the maximum number of local variables of this frame.
*/
public int getLocals() {
return locals;
}
/**
* Returns the maximum stack size of this frame.
*
* @return the maximum stack size of this frame.
*/
public int getMaxStackSize() {
return values.length - locals;
}
/**
* Returns the value of the given local variable.
*
* @param i
* a local variable index.
* @return the value of the given local variable.
* @throws IndexOutOfBoundsException
* if the variable does not exist.
*/
public V getLocal(final int i) throws IndexOutOfBoundsException {
if (i >= locals) {
throw new IndexOutOfBoundsException(
"Trying to access an inexistant local variable");
}
return values[i];
}
/**
* Sets the value of the given local variable.
*
* @param i
* a local variable index.
* @param value
* the new value of this local variable.
* @throws IndexOutOfBoundsException
* if the variable does not exist.
*/
public void setLocal(final int i, final V value)
throws IndexOutOfBoundsException {
if (i >= locals) {
throw new IndexOutOfBoundsException(
"Trying to access an inexistant local variable " + i);
}
values[i] = value;
}
/**
* Returns the number of values in the operand stack of this frame. Long and
* double values are treated as single values.
*
* @return the number of values in the operand stack of this frame.
*/
public int getStackSize() {
return top;
}
/**
* Returns the value of the given operand stack slot.
*
* @param i
* the index of an operand stack slot.
* @return the value of the given operand stack slot.
* @throws IndexOutOfBoundsException
* if the operand stack slot does not exist.
*/
public V getStack(final int i) throws IndexOutOfBoundsException {
return values[i + locals];
}
/**
* Clears the operand stack of this frame.
*/
public void clearStack() {
top = 0;
}
/**
* Pops a value from the operand stack of this frame.
*
* @return the value that has been popped from the stack.
* @throws IndexOutOfBoundsException
* if the operand stack is empty.
*/
public V pop() throws IndexOutOfBoundsException {
if (top == 0) {
throw new IndexOutOfBoundsException(
"Cannot pop operand off an empty stack.");
}
return values[--top + locals];
}
/**
* Pushes a value into the operand stack of this frame.
*
* @param value
* the value that must be pushed into the stack.
* @throws IndexOutOfBoundsException
* if the operand stack is full.
*/
public void push(final V value) throws IndexOutOfBoundsException {
if (top + locals >= values.length) {
throw new IndexOutOfBoundsException(
"Insufficient maximum stack size.");
}
values[top++ + locals] = value;
}
public void execute(final AbstractInsnNode insn,
final Interpreter interpreter) throws AnalyzerException {
V value1, value2, value3, value4;
List values;
int var;
switch (insn.getOpcode()) {
case Opcodes.NOP:
break;
case Opcodes.ACONST_NULL:
case Opcodes.ICONST_M1:
case Opcodes.ICONST_0:
case Opcodes.ICONST_1:
case Opcodes.ICONST_2:
case Opcodes.ICONST_3:
case Opcodes.ICONST_4:
case Opcodes.ICONST_5:
case Opcodes.LCONST_0:
case Opcodes.LCONST_1:
case Opcodes.FCONST_0:
case Opcodes.FCONST_1:
case Opcodes.FCONST_2:
case Opcodes.DCONST_0:
case Opcodes.DCONST_1:
case Opcodes.BIPUSH:
case Opcodes.SIPUSH:
case Opcodes.LDC:
push(interpreter.newOperation(insn));
break;
case Opcodes.ILOAD:
case Opcodes.LLOAD:
case Opcodes.FLOAD:
case Opcodes.DLOAD:
case Opcodes.ALOAD:
push(interpreter.copyOperation(insn,
getLocal(((VarInsnNode) insn).var)));
break;
case Opcodes.IALOAD:
case Opcodes.LALOAD:
case Opcodes.FALOAD:
case Opcodes.DALOAD:
case Opcodes.AALOAD:
case Opcodes.BALOAD:
case Opcodes.CALOAD:
case Opcodes.SALOAD:
value2 = pop();
value1 = pop();
push(interpreter.binaryOperation(insn, value1, value2));
break;
case Opcodes.ISTORE:
case Opcodes.LSTORE:
case Opcodes.FSTORE:
case Opcodes.DSTORE:
case Opcodes.ASTORE:
value1 = interpreter.copyOperation(insn, pop());
var = ((VarInsnNode) insn).var;
setLocal(var, value1);
if (value1.getSize() == 2) {
setLocal(var + 1, interpreter.newValue(null));
}
if (var > 0) {
Value local = getLocal(var - 1);
if (local != null && local.getSize() == 2) {
setLocal(var - 1, interpreter.newValue(null));
}
}
break;
case Opcodes.IASTORE:
case Opcodes.LASTORE:
case Opcodes.FASTORE:
case Opcodes.DASTORE:
case Opcodes.AASTORE:
case Opcodes.BASTORE:
case Opcodes.CASTORE:
case Opcodes.SASTORE:
value3 = pop();
value2 = pop();
value1 = pop();
interpreter.ternaryOperation(insn, value1, value2, value3);
break;
case Opcodes.POP:
if (pop().getSize() == 2) {
throw new AnalyzerException(insn, "Illegal use of POP");
}
break;
case Opcodes.POP2:
if (pop().getSize() == 1) {
if (pop().getSize() != 1) {
throw new AnalyzerException(insn, "Illegal use of POP2");
}
}
break;
case Opcodes.DUP:
value1 = pop();
if (value1.getSize() != 1) {
throw new AnalyzerException(insn, "Illegal use of DUP");
}
push(value1);
push(interpreter.copyOperation(insn, value1));
break;
case Opcodes.DUP_X1:
value1 = pop();
value2 = pop();
if (value1.getSize() != 1 || value2.getSize() != 1) {
throw new AnalyzerException(insn, "Illegal use of DUP_X1");
}
push(interpreter.copyOperation(insn, value1));
push(value2);
push(value1);
break;
case Opcodes.DUP_X2:
value1 = pop();
if (value1.getSize() == 1) {
value2 = pop();
if (value2.getSize() == 1) {
value3 = pop();
if (value3.getSize() == 1) {
push(interpreter.copyOperation(insn, value1));
push(value3);
push(value2);
push(value1);
break;
}
} else {
push(interpreter.copyOperation(insn, value1));
push(value2);
push(value1);
break;
}
}
throw new AnalyzerException(insn, "Illegal use of DUP_X2");
case Opcodes.DUP2:
value1 = pop();
if (value1.getSize() == 1) {
value2 = pop();
if (value2.getSize() == 1) {
push(value2);
push(value1);
push(interpreter.copyOperation(insn, value2));
push(interpreter.copyOperation(insn, value1));
break;
}
} else {
push(value1);
push(interpreter.copyOperation(insn, value1));
break;
}
throw new AnalyzerException(insn, "Illegal use of DUP2");
case Opcodes.DUP2_X1:
value1 = pop();
if (value1.getSize() == 1) {
value2 = pop();
if (value2.getSize() == 1) {
value3 = pop();
if (value3.getSize() == 1) {
push(interpreter.copyOperation(insn, value2));
push(interpreter.copyOperation(insn, value1));
push(value3);
push(value2);
push(value1);
break;
}
}
} else {
value2 = pop();
if (value2.getSize() == 1) {
push(interpreter.copyOperation(insn, value1));
push(value2);
push(value1);
break;
}
}
throw new AnalyzerException(insn, "Illegal use of DUP2_X1");
case Opcodes.DUP2_X2:
value1 = pop();
if (value1.getSize() == 1) {
value2 = pop();
if (value2.getSize() == 1) {
value3 = pop();
if (value3.getSize() == 1) {
value4 = pop();
if (value4.getSize() == 1) {
push(interpreter.copyOperation(insn, value2));
push(interpreter.copyOperation(insn, value1));
push(value4);
push(value3);
push(value2);
push(value1);
break;
}
} else {
push(interpreter.copyOperation(insn, value2));
push(interpreter.copyOperation(insn, value1));
push(value3);
push(value2);
push(value1);
break;
}
}
} else {
value2 = pop();
if (value2.getSize() == 1) {
value3 = pop();
if (value3.getSize() == 1) {
push(interpreter.copyOperation(insn, value1));
push(value3);
push(value2);
push(value1);
break;
}
} else {
push(interpreter.copyOperation(insn, value1));
push(value2);
push(value1);
break;
}
}
throw new AnalyzerException(insn, "Illegal use of DUP2_X2");
case Opcodes.SWAP:
value2 = pop();
value1 = pop();
if (value1.getSize() != 1 || value2.getSize() != 1) {
throw new AnalyzerException(insn, "Illegal use of SWAP");
}
push(interpreter.copyOperation(insn, value2));
push(interpreter.copyOperation(insn, value1));
break;
case Opcodes.IADD:
case Opcodes.LADD:
case Opcodes.FADD:
case Opcodes.DADD:
case Opcodes.ISUB:
case Opcodes.LSUB:
case Opcodes.FSUB:
case Opcodes.DSUB:
case Opcodes.IMUL:
case Opcodes.LMUL:
case Opcodes.FMUL:
case Opcodes.DMUL:
case Opcodes.IDIV:
case Opcodes.LDIV:
case Opcodes.FDIV:
case Opcodes.DDIV:
case Opcodes.IREM:
case Opcodes.LREM:
case Opcodes.FREM:
case Opcodes.DREM:
value2 = pop();
value1 = pop();
push(interpreter.binaryOperation(insn, value1, value2));
break;
case Opcodes.INEG:
case Opcodes.LNEG:
case Opcodes.FNEG:
case Opcodes.DNEG:
push(interpreter.unaryOperation(insn, pop()));
break;
case Opcodes.ISHL:
case Opcodes.LSHL:
case Opcodes.ISHR:
case Opcodes.LSHR:
case Opcodes.IUSHR:
case Opcodes.LUSHR:
case Opcodes.IAND:
case Opcodes.LAND:
case Opcodes.IOR:
case Opcodes.LOR:
case Opcodes.IXOR:
case Opcodes.LXOR:
value2 = pop();
value1 = pop();
push(interpreter.binaryOperation(insn, value1, value2));
break;
case Opcodes.IINC:
var = ((IincInsnNode) insn).var;
setLocal(var, interpreter.unaryOperation(insn, getLocal(var)));
break;
case Opcodes.I2L:
case Opcodes.I2F:
case Opcodes.I2D:
case Opcodes.L2I:
case Opcodes.L2F:
case Opcodes.L2D:
case Opcodes.F2I:
case Opcodes.F2L:
case Opcodes.F2D:
case Opcodes.D2I:
case Opcodes.D2L:
case Opcodes.D2F:
case Opcodes.I2B:
case Opcodes.I2C:
case Opcodes.I2S:
push(interpreter.unaryOperation(insn, pop()));
break;
case Opcodes.LCMP:
case Opcodes.FCMPL:
case Opcodes.FCMPG:
case Opcodes.DCMPL:
case Opcodes.DCMPG:
value2 = pop();
value1 = pop();
push(interpreter.binaryOperation(insn, value1, value2));
break;
case Opcodes.IFEQ:
case Opcodes.IFNE:
case Opcodes.IFLT:
case Opcodes.IFGE:
case Opcodes.IFGT:
case Opcodes.IFLE:
interpreter.unaryOperation(insn, pop());
break;
case Opcodes.IF_ICMPEQ:
case Opcodes.IF_ICMPNE:
case Opcodes.IF_ICMPLT:
case Opcodes.IF_ICMPGE:
case Opcodes.IF_ICMPGT:
case Opcodes.IF_ICMPLE:
case Opcodes.IF_ACMPEQ:
case Opcodes.IF_ACMPNE:
value2 = pop();
value1 = pop();
interpreter.binaryOperation(insn, value1, value2);
break;
case Opcodes.GOTO:
break;
case Opcodes.JSR:
push(interpreter.newOperation(insn));
break;
case Opcodes.RET:
break;
case Opcodes.TABLESWITCH:
case Opcodes.LOOKUPSWITCH:
interpreter.unaryOperation(insn, pop());
break;
case Opcodes.IRETURN:
case Opcodes.LRETURN:
case Opcodes.FRETURN:
case Opcodes.DRETURN:
case Opcodes.ARETURN:
value1 = pop();
interpreter.unaryOperation(insn, value1);
interpreter.returnOperation(insn, value1, returnValue);
break;
case Opcodes.RETURN:
if (returnValue != null) {
throw new AnalyzerException(insn, "Incompatible return type");
}
break;
case Opcodes.GETSTATIC:
push(interpreter.newOperation(insn));
break;
case Opcodes.PUTSTATIC:
interpreter.unaryOperation(insn, pop());
break;
case Opcodes.GETFIELD:
push(interpreter.unaryOperation(insn, pop()));
break;
case Opcodes.PUTFIELD:
value2 = pop();
value1 = pop();
interpreter.binaryOperation(insn, value1, value2);
break;
case Opcodes.INVOKEVIRTUAL:
case Opcodes.INVOKESPECIAL:
case Opcodes.INVOKESTATIC:
case Opcodes.INVOKEINTERFACE: {
values = new ArrayList();
String desc = ((MethodInsnNode) insn).desc;
for (int i = Type.getArgumentTypes(desc).length; i > 0; --i) {
values.add(0, pop());
}
if (insn.getOpcode() != Opcodes.INVOKESTATIC) {
values.add(0, pop());
}
if (Type.getReturnType(desc) == Type.VOID_TYPE) {
interpreter.naryOperation(insn, values);
} else {
push(interpreter.naryOperation(insn, values));
}
break;
}
case Opcodes.INVOKEDYNAMIC: {
values = new ArrayList();
String desc = ((InvokeDynamicInsnNode) insn).desc;
for (int i = Type.getArgumentTypes(desc).length; i > 0; --i) {
values.add(0, pop());
}
if (Type.getReturnType(desc) == Type.VOID_TYPE) {
interpreter.naryOperation(insn, values);
} else {
push(interpreter.naryOperation(insn, values));
}
break;
}
case Opcodes.NEW:
push(interpreter.newOperation(insn));
break;
case Opcodes.NEWARRAY:
case Opcodes.ANEWARRAY:
case Opcodes.ARRAYLENGTH:
push(interpreter.unaryOperation(insn, pop()));
break;
case Opcodes.ATHROW:
interpreter.unaryOperation(insn, pop());
break;
case Opcodes.CHECKCAST:
case Opcodes.INSTANCEOF:
push(interpreter.unaryOperation(insn, pop()));
break;
case Opcodes.MONITORENTER:
case Opcodes.MONITOREXIT:
interpreter.unaryOperation(insn, pop());
break;
case Opcodes.MULTIANEWARRAY:
values = new ArrayList();
for (int i = ((MultiANewArrayInsnNode) insn).dims; i > 0; --i) {
values.add(0, pop());
}
push(interpreter.naryOperation(insn, values));
break;
case Opcodes.IFNULL:
case Opcodes.IFNONNULL:
interpreter.unaryOperation(insn, pop());
break;
default:
throw new RuntimeException("Illegal opcode " + insn.getOpcode());
}
}
/**
* Merges this frame with the given frame.
*
* @param frame
* a frame.
* @param interpreter
* the interpreter used to merge values.
* @return true if this frame has been changed as a result of the
* merge operation, or false otherwise.
* @throws AnalyzerException
* if the frames have incompatible sizes.
*/
public boolean merge(final Frame frame,
final Interpreter interpreter) throws AnalyzerException {
if (top != frame.top) {
throw new AnalyzerException(null, "Incompatible stack heights");
}
boolean changes = false;
for (int i = 0; i < locals + top; ++i) {
V v = interpreter.merge(values[i], frame.values[i]);
if (!v.equals(values[i])) {
values[i] = v;
changes = true;
}
}
return changes;
}
/**
* Merges this frame with the given frame (case of a RET instruction).
*
* @param frame
* a frame
* @param access
* the local variables that have been accessed by the subroutine
* to which the RET instruction corresponds.
* @return true if this frame has been changed as a result of the
* merge operation, or false otherwise.
*/
public boolean merge(final Frame frame, final boolean[] access) {
boolean changes = false;
for (int i = 0; i < locals; ++i) {
if (!access[i] && !values[i].equals(frame.values[i])) {
values[i] = frame.values[i];
changes = true;
}
}
return changes;
}
/**
* Returns a string representation of this frame.
*
* @return a string representation of this frame.
*/
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < getLocals(); ++i) {
sb.append(getLocal(i));
}
sb.append(' ');
for (int i = 0; i < getStackSize(); ++i) {
sb.append(getStack(i).toString());
}
return sb.toString();
}
}