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/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2019 Guardsquare NV
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package proguard.optimize.evaluation;
import proguard.classfile.*;
import proguard.classfile.attribute.CodeAttribute;
import proguard.classfile.constant.*;
import proguard.classfile.instruction.ConstantInstruction;
import proguard.evaluation.*;
import proguard.evaluation.value.*;
/**
* This InvocationUnit tags reference values of retrieved fields, passed method
* parameters, method return values, and caught exceptions, so they can be
* traced throughout the execution of a method. The tags are instruction offsets
* or parameter indices (not parameter offsets).
*
* @see TracedReferenceValue
* @see InstructionOffsetValue
* @author Eric Lafortune
*/
public class ReferenceTracingInvocationUnit
extends SimplifiedInvocationUnit
{
private final SimplifiedInvocationUnit invocationUnit;
private int offset;
/**
* Creates a new ReferenceTracingInvocationUnit.
* @param invocationUnit the invocation unit to which invocations will
* be delegated.
*/
public ReferenceTracingInvocationUnit(SimplifiedInvocationUnit invocationUnit)
{
this.invocationUnit = invocationUnit;
}
// Implementations for InvocationUnit.
public void enterExceptionHandler(Clazz clazz,
Method method,
CodeAttribute codeAttribute,
int offset,
int catchType,
Stack stack)
{
this.offset = offset;
super.enterExceptionHandler(clazz,
method,
codeAttribute,
offset,
catchType,
stack);
}
public void invokeMember(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, ConstantInstruction constantInstruction, Stack stack)
{
this.offset = offset;
super.invokeMember(clazz,
method,
codeAttribute,
offset,
constantInstruction,
stack);
}
// Implementations for SimplifiedInvocationUnit.
public Value getExceptionValue(Clazz clazz,
ClassConstant catchClassConstant)
{
return trace(invocationUnit.getExceptionValue(clazz, catchClassConstant),
offset | InstructionOffsetValue.EXCEPTION_HANDLER);
}
public void setFieldClassValue(Clazz clazz, RefConstant refConstant, ReferenceValue value)
{
invocationUnit.setFieldClassValue(clazz, refConstant, value);
}
public Value getFieldClassValue(Clazz clazz, RefConstant refConstant, String type)
{
return trace(invocationUnit.getFieldClassValue(clazz, refConstant, type),
offset | InstructionOffsetValue.FIELD_VALUE);
}
public void setFieldValue(Clazz clazz, RefConstant refConstant, Value value)
{
invocationUnit.setFieldValue(clazz, refConstant, value);
}
public Value getFieldValue(Clazz clazz, RefConstant refConstant, String type)
{
return trace(invocationUnit.getFieldValue(clazz, refConstant, type),
offset | InstructionOffsetValue.FIELD_VALUE);
}
public void setMethodParameterValue(Clazz clazz, RefConstant refConstant, int parameterIndex, Value value)
{
invocationUnit.setMethodParameterValue(clazz, refConstant, parameterIndex, value);
}
public Value getMethodParameterValue(Clazz clazz, Method method, int parameterIndex, String type, Clazz referencedClass)
{
Value parameterValue =
invocationUnit.getMethodParameterValue(clazz, method, parameterIndex, type, referencedClass);
// We're attaching the parameter index as a trace value. It doesn't
// take into account Category 2 values, so it is not compatible with
// variable indices.
return trace(parameterValue,
parameterIndex | InstructionOffsetValue.METHOD_PARAMETER);
}
public void setMethodReturnValue(Clazz clazz, Method method, Value value)
{
invocationUnit.setMethodReturnValue(clazz, method, value);
}
public Value getMethodReturnValue(Clazz clazz, RefConstant refConstant, String type)
{
Value returnValue =
invocationUnit.getMethodReturnValue(clazz, refConstant, type);
return trace(returnValue,
offset | InstructionOffsetValue.METHOD_RETURN_VALUE);
}
public Value getMethodReturnValue(Clazz clazz, InvokeDynamicConstant invokeDynamicConstant, String type)
{
Value returnValue =
invocationUnit.getMethodReturnValue(clazz, invokeDynamicConstant, type);
return trace(returnValue,
offset | InstructionOffsetValue.METHOD_RETURN_VALUE);
}
// Small utility methods.
/**
* Sets or replaces the trace value on a given value, if it's a
* reference value, returning the result.
*/
protected Value trace(Value value, int trace)
{
if (value.computationalType() != Value.TYPE_REFERENCE)
{
return value;
}
return trace(value, new InstructionOffsetValue(trace));
}
/**
* Sets or replaces the trace value on a given value, returning the result.
*/
protected Value trace(Value value, InstructionOffsetValue traceValue)
{
return new TracedReferenceValue(untrace(value).referenceValue(),
traceValue);
}
/**
* Removes the trace value from a given value, if present, returning the
* result.
*/
private Value untrace(Value value)
{
return value instanceof TracedReferenceValue ?
((TracedReferenceValue)value).getReferenceValue() :
value;
}
}