//
// Copyright (C) 2010 United States Government as represented by the
// Administrator of the National Aeronautics and Space Administration
// (NASA). All Rights Reserved.
//
// This software is distributed under the NASA Open Source Agreement
// (NOSA), version 1.3. The NOSA has been approved by the Open Source
// Initiative. See the file NOSA-1.3-JPF at the top of the distribution
// directory tree for the complete NOSA document.
//
// THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF ANY
// KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT
// LIMITED TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO
// SPECIFICATIONS, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
// A PARTICULAR PURPOSE, OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT
// THE SUBJECT SOFTWARE WILL BE ERROR FREE, OR ANY WARRANTY THAT
// DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE SUBJECT SOFTWARE.
//
package gov.nasa.jpf.jvm.bytecode;
import java.util.function.BiFunction;
import cmu.conditional.ChoiceFactory;
import cmu.conditional.Conditional;
import cmu.conditional.One;
import de.fosd.typechef.featureexpr.FeatureExpr;
import gov.nasa.jpf.jvm.JVMInstruction;
import gov.nasa.jpf.vm.Instruction;
import gov.nasa.jpf.vm.StackFrame;
import gov.nasa.jpf.vm.ThreadInfo;
/**
* this is used to return from a DirectCallStackFrame
*
* Note that it is NOT a ReturnInstruction, in case listeners monitor these
* and expect corresponding InvokeInstructions. Although this would seem intuitive, it
* would be pointless to derive because the ReturnInstruction.enter() does
* a lot of things we would have to cut off, i.e. it would require more effort
* to undo this (no sync, no return value, no pc advance on the returned-to
* stackframe etc.)
*
* However, having a dedicated direct call return instruction makes sense so
* that the ReturnInstruction of the called method does not have to handle
* direct calls specifically
*/
public class DIRECTCALLRETURN extends JVMInstruction implements gov.nasa.jpf.vm.ReturnInstruction {
@Override
public boolean isExtendedInstruction() {
return true;
}
public static final int OPCODE = 261;
@Override
public int getByteCode () {
return OPCODE;
}
@Override
public void accept(InstructionVisitor insVisitor) {
insVisitor.visit(this);
}
@SuppressWarnings("unchecked")
@Override
public Conditional<Instruction> execute (FeatureExpr ctx, ThreadInfo ti) {
// pop the current frame but do not advance the new top frame, and do
// not touch its operand stack
if (ti.getStackDepth() == 1){ // thread exit point (might be re-executed)
if (!ti.exit(ctx)){
return new One<Instruction>(this); // repeat, we couldn't get the lock
} else {
return (Conditional<Instruction>) One.NULL;
}
} else {
StackFrame frame = ti.popDirectCallFrame(ctx);
return frame.getPC();
}
}
@Override
public Conditional<Instruction> getNext(final FeatureExpr ctx, ThreadInfo ti) {
return ti.getPC().mapf(ctx, new BiFunction<FeatureExpr, Instruction, Conditional<Instruction>>() {
@Override
public Conditional<Instruction> apply(final FeatureExpr f, final Instruction y) {
return ChoiceFactory.create(ctx, new One<>(y.getNext()), new One<>(y));
}
}).simplify();
}
}