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package org.plumelib.bcelutil;
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001 The Apache Software Foundation. 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. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" and
* "Apache BCEL" must not be used to endorse or promote products
* derived from this software without prior written permission. For
* written permission, please contact [email protected].
*
* 5. Products derived from this software may not be called "Apache",
* "Apache BCEL", nor may "Apache" appear in their name, without
* prior written permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
* ITS 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* This PassVerifier verifies a method of class file according to pass 3, so-called structural
* verification as described in The Java Virtual Machine Specification, 2nd edition. More detailed
* information is to be found at the do_verify() method's documentation.
*
* @version $Id$
* @author Enver Haase
* @see #get_stack_types()
*/
@SuppressWarnings({"rawtypes", "nullness", "interning"}) // third-party code
public final class StackVer {
/* TODO: Throughout pass 3b, upper halves of LONG and DOUBLE
are represented by Type.UNKNOWN. This should be changed
in favour of LONG_Upper and DOUBLE_Upper as in pass 2. */
/**
* An InstructionContextQueue is a utility class that holds (InstructionContext, ArrayList) pairs
* in a Queue data structure. This is used to hold information about InstructionContext objects
* externally --- i.e. that information is not saved inside the InstructionContext object itself.
* This is useful to save the execution path of the symbolic execution of the Pass3bVerifier -
* this is not information that belongs into the InstructionContext object itself. Only at
* "execute()"ing time, an InstructionContext object will get the current information we have
* about its symbolic execution predecessors.
*/
private static final class InstructionContextQueue {
private List ics = new ArrayList();
private List> ecs =
new ArrayList>();
/**
* TODO
*
* @param ic
* @param executionChain
*/
public void add(InstructionContext ic, ArrayList executionChain) {
ics.add(ic);
ecs.add(executionChain);
}
/**
* TODO
*
* @return
*/
public boolean isEmpty() {
return ics.isEmpty();
}
/** TODO */
public void remove() {
this.remove(0);
}
/**
* TODO
*
* @param i
*/
public void remove(@NonNegative int i) {
ics.remove(i);
ecs.remove(i);
}
/**
* TODO
*
* @param i
* @return
*/
public InstructionContext getIC(@NonNegative int i) {
return ics.get(i);
}
/**
* TODO
*
* @param i
* @return
*/
public ArrayList getEC(@NonNegative int i) {
return ecs.get(i);
}
/**
* TODO
*
* @return
*/
public int size() {
return ics.size();
}
} // end Inner Class InstructionContextQueue
// /**
// * This modified version of InstContraintVisitor causes the verifier
// * not to load any other classes as part of verification (causing it
// * to presume that information in this class is correct. This is
// * necessary for efficiency and also prevents some other problems
// */
// private static class MyLimitedConstraintVisitor
// extends InstConstraintVisitor {
//
// public void visitLoadClass(LoadClass o){
// // System.out.println ("Skipping visitLoadClass " + o);
// }
// public void visitINVOKEVIRTUAL(INVOKEVIRTUAL o){
// // TODO JHP: This should really check the arguments (for when
// // we use this code as a verifier)
// // System.out.println ("Skipping invoke virtual " + o);
// }
//
// public void visitNEW (NEW o) {
// // All this does is make sure that the new object is as expected.
// // It fails if it can't find it, which we would prefer it not
// // to do.
// }
//
// public void visitLDC(LDC o){
// // Skipping check because LDC has new capabilities in 1.5 not
// // supported by this check (it allows constant classes in addition
// // to strings, integers, and floats
// }
//
// public void visitLDC_W(LDC_W o){
// // Skipping check because LDC has new capabilities in 1.5 not
// // supported by this check (it allows constant classes in addition
// // to strings, integers, and floats
// }
// }
/** In DEBUG mode, the verification algorithm is not randomized. */
private static final boolean DEBUG = true;
/** The Verifier that created this. */
// private Verifier myOwner;
/** The types on the stack for each instruction by byte code offset */
// Set by do_stack_ver().
private @MonotonicNonNull StackTypes stack_types;
/**
* This class should only be instantiated by a Verifier.
*
* @see org.apache.bcel.verifier.Verifier
*/
public StackVer() {}
/**
* Return the types on the stack at each byte code offset. Only valid after do_stack_ver() is
* called.
*
* @return the StackTypes object for the method being verified
*/
public StackTypes get_stack_types() {
return stack_types;
}
/**
* Whenever the outgoing frame situation of an InstructionContext changes, all its successors are
* put [back] into the queue [as if they were unvisited]. The proof of termination is about the
* existence of a fix point of frame merging.
*/
private void circulationPump(
ControlFlowGraph cfg,
InstructionContext start,
Frame vanillaFrame,
InstConstraintVisitor icv,
ExecutionVisitor ev) {
final Random random = new Random();
InstructionContextQueue icq = new InstructionContextQueue();
stack_types.set(start.getInstruction().getPosition(), vanillaFrame);
// new ArrayList() <=> no Instruction was executed before
start.execute(vanillaFrame, new ArrayList(), icv, ev);
// => Top-Level routine (no jsr call before)
icq.add(start, new ArrayList());
// LOOP!
while (!icq.isEmpty()) {
InstructionContext u;
ArrayList ec;
if (!DEBUG) {
int r = random.nextInt(icq.size());
u = icq.getIC(r);
ec = icq.getEC(r);
icq.remove(r);
} else {
u = icq.getIC(0);
ec = icq.getEC(0);
icq.remove(0);
}
// this makes Java grumpy
// ArrayList oldchain = (ArrayList) (ec.clone());
ArrayList oldchain = new ArrayList(ec);
// this makes Java grumpy
// ArrayList newchain = (ArrayList) (ec.clone());
ArrayList newchain = new ArrayList(ec);
newchain.add(u);
if ((u.getInstruction().getInstruction()) instanceof RET) {
// We can only follow _one_ successor, the one after the
// JSR that was recently executed.
RET ret = (RET) (u.getInstruction().getInstruction());
ReturnaddressType t =
(ReturnaddressType) u.getOutFrame(oldchain).getLocals().get(ret.getIndex());
InstructionContext theSuccessor = cfg.contextOf(t.getTarget());
// Sanity check
InstructionContext lastJSR = null;
int skip_jsr = 0;
for (int ss = oldchain.size() - 1; ss >= 0; ss--) {
if (skip_jsr < 0) {
throw new AssertionViolatedException("More RET than JSR in execution chain?!");
}
// System.err.println("+"+oldchain.get(ss));
if ((oldchain.get(ss)).getInstruction().getInstruction() instanceof JsrInstruction) {
if (skip_jsr == 0) {
lastJSR = oldchain.get(ss);
break;
}
skip_jsr--;
}
if ((oldchain.get(ss)).getInstruction().getInstruction() instanceof RET) {
skip_jsr++;
}
}
if (lastJSR == null) {
throw new AssertionViolatedException(
"RET without a JSR before in ExecutionChain?! EC: '" + oldchain + "'.");
}
JsrInstruction jsr = (JsrInstruction) (lastJSR.getInstruction().getInstruction());
if (theSuccessor != (cfg.contextOf(jsr.physicalSuccessor()))) {
throw new AssertionViolatedException(
"RET '"
+ u.getInstruction()
+ "' info inconsistent: jump back to '"
+ theSuccessor
+ "' or '"
+ cfg.contextOf(jsr.physicalSuccessor())
+ "'?");
}
Frame f = u.getOutFrame(oldchain);
stack_types.set(theSuccessor.getInstruction().getPosition(), f);
if (theSuccessor.execute(f, newchain, icv, ev)) {
// This makes 5.0 grumpy: icq.add(theSuccessor, (ArrayList) newchain.clone());
icq.add(theSuccessor, new ArrayList(newchain));
}
} else { // "not a ret"
// Normal successors. Add them to the queue of successors.
InstructionContext[] succs = u.getSuccessors();
for (int s = 0; s < succs.length; s++) {
InstructionContext v = succs[s];
Frame f = u.getOutFrame(oldchain);
stack_types.set(v.getInstruction().getPosition(), f);
if (v.execute(f, newchain, icv, ev)) {
// This makes 5.0 grumpy: icq.add(v, (ArrayList) newchain.clone());
icq.add(v, new ArrayList(newchain));
}
}
} // end "not a ret"
// Exception Handlers. Add them to the queue of successors.
// [subroutines are never protected; mandated by JustIce]
ExceptionHandler[] exc_hds = u.getExceptionHandlers();
for (int s = 0; s < exc_hds.length; s++) {
InstructionContext v = cfg.contextOf(exc_hds[s].getHandlerStart());
// TODO: the "oldchain" and "newchain" is used to determine the subroutine
// we're in (by searching for the last JSR) by the InstructionContext
// implementation. Therefore, we should not use this chain mechanism
// when dealing with exception handlers.
// Example: a JSR with an exception handler as its successor does not
// mean we're in a subroutine if we go to the exception handler.
// We should address this problem later; by now we simply "cut" the chain
// by using an empty chain for the exception handlers.
// if (v.execute(new Frame(u.getOutFrame(oldchain).getLocals(), new OperandStack
// (u.getOutFrame().getStack().maxStack(), (exc_hds[s].getExceptionType()==null?
// Type.THROWABLE : exc_hds[s].getExceptionType())) ), newchain), icv, ev){
// icq.add(v, (ArrayList) newchain.clone());
Frame f =
new Frame(
u.getOutFrame(oldchain).getLocals(),
new OperandStack(
u.getOutFrame(oldchain).getStack().maxStack(),
(exc_hds[s].getExceptionType() == null
? Type.THROWABLE
: exc_hds[s].getExceptionType())));
stack_types.set(v.getInstruction().getPosition(), f);
if (v.execute(f, new ArrayList(), icv, ev)) {
icq.add(v, new ArrayList());
}
}
} // while (!icq.isEmpty()) END
InstructionHandle ih = start.getInstruction();
do {
if ((ih.getInstruction() instanceof ReturnInstruction) && (!(cfg.isDead(ih)))) {
InstructionContext ic = cfg.contextOf(ih);
Frame f = ic.getOutFrame(new ArrayList());
// TODO: This is buggy, we check only the top-level return instructions
// this way. Maybe some maniac returns from a method when in a subroutine?
LocalVariables lvs = f.getLocals();
for (int i = 0; i < lvs.maxLocals(); i++) {
if (lvs.get(i) instanceof UninitializedObjectType) {
this.addMessage(
"Warning: ReturnInstruction '"
+ ic
+ "' may leave method with an uninitialized object in the local variables array '"
+ lvs
+ "'.");
}
}
OperandStack os = f.getStack();
for (int i = 0; i < os.size(); i++) {
if (os.peek(i) instanceof UninitializedObjectType) {
this.addMessage(
"Warning: ReturnInstruction '"
+ ic
+ "' may leave method with an uninitialized object on the operand stack '"
+ os
+ "'.");
}
}
}
} while ((ih = ih.getNext()) != null);
}
/**
* Implements the pass 3b data flow analysis as described in the Java Virtual Machine
* Specification, Second Edition. As it is doing so it keeps track of the stack and local
* variables at each instruction.
*
* @param mg MethodGen for the method to be verified
* @return the VerificationResult
* @see org.apache.bcel.verifier.statics.Pass2Verifier#getLocalVariablesInfo(int)
*/
public VerificationResult do_stack_ver(MethodGen mg) {
/*
if (! myOwner.doPass3a(method_no).equals(VerificationResult.VR_OK)){
return VerificationResult.VR_NOTYET;
}
*/
// Pass 3a ran before, so it's safe to assume the JavaClass object is
// in the BCEL repository.
// JavaClass jc = Repository.lookupClass(myOwner.getClassName());
ConstantPoolGen constantPoolGen = mg.getConstantPool();
// Init Visitors
InstConstraintVisitor icv = new LimitedConstraintVisitor();
icv.setConstantPoolGen(constantPoolGen);
ExecutionVisitor ev = new ExecutionVisitor();
ev.setConstantPoolGen(constantPoolGen);
try {
stack_types = new StackTypes(mg);
icv.setMethodGen(mg);
////////////// DFA BEGINS HERE ////////////////
if (!(mg.isAbstract() || mg.isNative())) { // IF mg HAS CODE (See pass 2)
// false says don't check if jsr subroutine is covered by exception handler
ControlFlowGraph cfg = new ControlFlowGraph(mg, false);
// Build the initial frame situation for this method.
Frame f = new Frame(mg.getMaxLocals(), mg.getMaxStack());
if (!mg.isStatic()) {
if (mg.getName().equals(Const.CONSTRUCTOR_NAME)) {
Frame.setThis(new UninitializedObjectType(new ObjectType(mg.getClassName())));
f.getLocals().set(0, Frame.getThis());
} else {
@SuppressWarnings("nullness") // unannotated: org.apache.bcel.verifier.structurals.Frame
@NonNull
UninitializedObjectType dummy = null;
Frame.setThis(dummy);
f.getLocals().set(0, new ObjectType(mg.getClassName()));
}
}
Type[] argtypes = mg.getArgumentTypes();
int twoslotoffset = 0;
for (int j = 0; j < argtypes.length; j++) {
if (argtypes[j] == Type.SHORT
|| argtypes[j] == Type.BYTE
|| argtypes[j] == Type.CHAR
|| argtypes[j] == Type.BOOLEAN) {
argtypes[j] = Type.INT;
}
f.getLocals().set(twoslotoffset + j + (mg.isStatic() ? 0 : 1), argtypes[j]);
if (argtypes[j].getSize() == 2) {
twoslotoffset++;
f.getLocals().set(twoslotoffset + j + (mg.isStatic() ? 0 : 1), Type.UNKNOWN);
}
}
circulationPump(cfg, cfg.contextOf(mg.getInstructionList().getStart()), f, icv, ev);
}
} catch (VerifierConstraintViolatedException ce) {
ce.extendMessage("Constraint violated in method '" + mg + "':\n", "");
return new VerificationResult(VerificationResult.VERIFIED_REJECTED, ce.getMessage());
} catch (RuntimeException re) {
// These are internal errors
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
re.printStackTrace(pw);
throw new AssertionViolatedException(
"Some RuntimeException occured while verify()ing class '"
+ mg.getClassName()
+ "', method '"
+ mg
+ "'. Original RuntimeException's stack trace:\n---\n"
+ sw
+ "---\n");
}
return VerificationResult.VR_OK;
}
// Code from PassVerifier in BCEL so that we don't have to extend it
/** The (warning) messages. */
private ArrayList messages = new ArrayList();
/**
* This method adds a (warning) message to the message pool of this PassVerifier.
*
* @param message the String containing the warning message
*/
public void addMessage(String message) {
messages.add(message);
}
}
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