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|
//-----------------------------------------------------------------------------
//
// Copyright (C) Microsoft Corporation. All Rights Reserved.
//
//-----------------------------------------------------------------------------
using System;
using System.Diagnostics.Contracts;
using System.Collections.Generic;
using Microsoft.Boogie;
using Microsoft.Boogie.VCExprAST;
using Microsoft.Boogie.Simplify;
using VC;
using Microsoft.Boogie.Z3;
using System.Collections;
using System.IO;
using Microsoft.AbstractInterpretationFramework;
using Graphing;
namespace Microsoft.Boogie.Houdini {
class ReadOnlyDictionary<K, V> {
private Dictionary<K, V> dictionary;
public ReadOnlyDictionary(Dictionary<K, V> dictionary) {
this.dictionary = dictionary;
}
public Dictionary<K, V>.KeyCollection Keys {
get { return this.dictionary.Keys; }
}
public bool TryGetValue(K k, out V v) {
return this.dictionary.TryGetValue(k, out v);
}
public bool ContainsKey(K k) {
return this.dictionary.ContainsKey(k);
}
}
public abstract class HoudiniObserver {
public virtual void UpdateStart(Program program, int numConstants) { }
public virtual void UpdateIteration() { }
public virtual void UpdateImplementation(Implementation implementation) { }
public virtual void UpdateAssignment(Dictionary<string, bool> assignment) { }
public virtual void UpdateOutcome(ProverInterface.Outcome outcome) { }
public virtual void UpdateEnqueue(Implementation implementation) { }
public virtual void UpdateDequeue() { }
public virtual void UpdateConstant(string constantName) { }
public virtual void UpdateEnd(bool isNormalEnd) { }
public virtual void UpdateFlushStart() { }
public virtual void UpdateFlushFinish() { }
public virtual void SeeException(string msg) { }
}
public class IterationTimer<K> {
private Dictionary<K, List<double>> times;
public IterationTimer() {
times = new Dictionary<K, List<double>>();
}
public void AddTime(K key, double timeMS) {
List<double> oldList;
times.TryGetValue(key, out oldList);
if (oldList == null) {
oldList = new List<double>();
}
else {
times.Remove(key);
}
oldList.Add(timeMS);
times.Add(key, oldList);
}
public void PrintTimes(TextWriter wr) {
wr.WriteLine("Total procedures: {0}", times.Count);
double total = 0;
int totalIters = 0;
foreach (KeyValuePair<K, List<double>> kv in times) {
int curIter = 0;
wr.WriteLine("Times for {0}:", kv.Key);
foreach (double v in kv.Value) {
wr.WriteLine(" ({0})\t{1}ms", curIter, v);
total += v;
curIter++;
}
totalIters += curIter;
}
total = total / 1000.0;
wr.WriteLine("Total time: {0} (s)", total);
wr.WriteLine("Avg: {0} (s/iter)", total / totalIters);
}
}
public class HoudiniTimer : HoudiniObserver {
private DateTime startT;
private Implementation curImp;
private IterationTimer<string> times;
private TextWriter wr;
public HoudiniTimer(TextWriter wr) {
this.wr = wr;
times = new IterationTimer<string>();
}
public override void UpdateIteration() {
startT = DateTime.Now;
}
public override void UpdateImplementation(Implementation implementation) {
curImp = implementation;
}
public override void UpdateOutcome(ProverInterface.Outcome o) {
Contract.Assert(curImp != null);
DateTime endT = DateTime.Now;
times.AddTime(curImp.Name, (endT - startT).TotalMilliseconds); // assuming names are unique
}
public void PrintTimes() {
wr.WriteLine("-----------------------------------------");
wr.WriteLine("Times for each iteration for each procedure");
wr.WriteLine("-----------------------------------------");
times.PrintTimes(wr);
}
}
public class HoudiniTextReporter : HoudiniObserver {
private TextWriter wr;
private int currentIteration = -1;
public HoudiniTextReporter(TextWriter wr) {
this.wr = wr;
}
public override void UpdateStart(Program program, int numConstants) {
wr.WriteLine("Houdini started:" + program.ToString() + " #constants: " + numConstants.ToString());
currentIteration = -1;
wr.Flush();
}
public override void UpdateIteration() {
currentIteration++;
wr.WriteLine("---------------------------------------");
wr.WriteLine("Houdini iteration #" + currentIteration);
wr.Flush();
}
public override void UpdateImplementation(Implementation implementation) {
wr.WriteLine("implementation under analysis :" + implementation.Name);
wr.Flush();
}
public override void UpdateAssignment(Dictionary<string, bool> assignment) {
bool firstTime = true;
wr.Write("assignment under analysis : axiom (");
foreach (KeyValuePair<string, bool> kv in assignment) {
if (!firstTime) wr.Write(" && "); else firstTime = false;
string valString; // ugliness to get it lower cased
if (kv.Value) valString = "true"; else valString = "false";
wr.Write(kv.Key + " == " + valString);
}
wr.WriteLine(");");
wr.Flush();
}
public override void UpdateOutcome(ProverInterface.Outcome outcome) {
wr.WriteLine("analysis outcome :" + outcome);
wr.Flush();
}
public override void UpdateEnqueue(Implementation implementation) {
wr.WriteLine("worklist enqueue :" + implementation.Name);
wr.Flush();
}
public override void UpdateDequeue() {
wr.WriteLine("worklist dequeue");
wr.Flush();
}
public override void UpdateConstant(string constantName) {
wr.WriteLine("constant disabled : " + constantName);
wr.Flush();
}
public override void UpdateEnd(bool isNormalEnd) {
wr.WriteLine("Houdini ended: " + (isNormalEnd ? "Normal" : "Abnormal"));
wr.WriteLine("Number of iterations: " + (this.currentIteration + 1));
wr.Flush();
}
public override void UpdateFlushStart() {
wr.WriteLine("***************************************");
wr.WriteLine("Flushing remaining implementations");
wr.Flush();
}
public override void UpdateFlushFinish() {
wr.WriteLine("***************************************");
wr.WriteLine("Flushing finished");
wr.Flush();
}
public override void SeeException(string msg) {
wr.WriteLine("Caught exception: " + msg);
wr.Flush();
}
}
public abstract class ObservableHoudini {
private List<HoudiniObserver> observers = new List<HoudiniObserver>();
public void AddObserver(HoudiniObserver observer) {
if (!observers.Contains(observer))
observers.Add(observer);
}
private delegate void NotifyDelegate(HoudiniObserver observer);
private void Notify(NotifyDelegate notifyDelegate) {
foreach (HoudiniObserver observer in observers) {
notifyDelegate(observer);
}
}
protected void NotifyStart(Program program, int numConstants) {
NotifyDelegate notifyDelegate = (NotifyDelegate)delegate(HoudiniObserver r) { r.UpdateStart(program, numConstants); };
Notify(notifyDelegate);
}
protected void NotifyIteration() {
Notify((NotifyDelegate)delegate(HoudiniObserver r) { r.UpdateIteration(); });
}
protected void NotifyImplementation(Implementation implementation) {
Notify((NotifyDelegate)delegate(HoudiniObserver r) { r.UpdateImplementation(implementation); });
}
protected void NotifyAssignment(Dictionary<string, bool> assignment) {
Notify((NotifyDelegate)delegate(HoudiniObserver r) { r.UpdateAssignment(assignment); });
}
protected void NotifyOutcome(ProverInterface.Outcome outcome) {
Notify((NotifyDelegate)delegate(HoudiniObserver r) { r.UpdateOutcome(outcome); });
}
protected void NotifyEnqueue(Implementation implementation) {
Notify((NotifyDelegate)delegate(HoudiniObserver r) { r.UpdateEnqueue(implementation); });
}
protected void NotifyDequeue() {
Notify((NotifyDelegate)delegate(HoudiniObserver r) { r.UpdateDequeue(); });
}
protected void NotifyConstant(string constantName) {
Notify((NotifyDelegate)delegate(HoudiniObserver r) { r.UpdateConstant(constantName); });
}
protected void NotifyEnd(bool isNormalEnd) {
Notify((NotifyDelegate)delegate(HoudiniObserver r) { r.UpdateEnd(isNormalEnd); });
}
protected void NotifyFlushStart() {
Notify((NotifyDelegate)delegate(HoudiniObserver r) { r.UpdateFlushStart(); });
}
protected void NotifyFlushFinish() {
Notify((NotifyDelegate)delegate(HoudiniObserver r) { r.UpdateFlushFinish(); });
}
protected void NotifyException(string msg) {
Notify((NotifyDelegate)delegate(HoudiniObserver r) { r.SeeException(msg); });
}
}
public class Houdini : ObservableHoudini {
private Program program;
private ReadOnlyDictionary<string, IdentifierExpr> houdiniConstants;
private ReadOnlyDictionary<Implementation, HoudiniSession> houdiniSessions;
private VCGen vcgen;
private Checker checker;
private Graph<Implementation> callGraph;
private bool continueAtError;
public Houdini(Program program, bool continueAtError) {
this.program = program;
this.callGraph = BuildCallGraph();
this.continueAtError = continueAtError;
this.houdiniConstants = CollectExistentialConstants();
Inline();
this.vcgen = new VCGen(program, CommandLineOptions.Clo.SimplifyLogFilePath, CommandLineOptions.Clo.SimplifyLogFileAppend);
this.checker = new Checker(vcgen, program, CommandLineOptions.Clo.SimplifyLogFilePath, CommandLineOptions.Clo.SimplifyLogFileAppend, CommandLineOptions.Clo.ProverKillTime);
Dictionary<Implementation, HoudiniSession> houdiniSessions = new Dictionary<Implementation, HoudiniSession>();
foreach (Implementation impl in callGraph.Nodes) {
// make a different simplify log file for each function
String simplifyLog = null;
if (CommandLineOptions.Clo.SimplifyLogFilePath != null) {
simplifyLog = impl.ToString() + CommandLineOptions.Clo.SimplifyLogFilePath;
}
HoudiniSession session = new HoudiniSession(vcgen, checker, program, impl, simplifyLog, CommandLineOptions.Clo.SimplifyLogFileAppend);
houdiniSessions.Add(impl, session);
}
this.houdiniSessions = new ReadOnlyDictionary<Implementation, HoudiniSession>(houdiniSessions);
}
private void Inline() {
if (CommandLineOptions.Clo.InlineDepth < 0)
return;
foreach (Implementation impl in callGraph.Nodes) {
impl.OriginalBlocks = impl.Blocks;
impl.OriginalLocVars = impl.LocVars;
}
foreach (Implementation impl in callGraph.Nodes) {
Inliner.ProcessImplementationForHoudini(program, impl);
}
foreach (Implementation impl in callGraph.Nodes) {
impl.OriginalBlocks = null;
impl.OriginalLocVars = null;
}
}
private ReadOnlyDictionary<string, IdentifierExpr> CollectExistentialConstants() {
Dictionary<string, IdentifierExpr> existentialConstants = new Dictionary<string, IdentifierExpr>();
foreach (Declaration decl in program.TopLevelDeclarations) {
Constant constant = decl as Constant;
if (constant != null) {
bool result = false;
if (constant.CheckBooleanAttribute("existential", ref result)) {
if (result == true)
existentialConstants.Add(constant.Name, new IdentifierExpr(Token.NoToken, constant));
}
}
}
return new ReadOnlyDictionary<string, IdentifierExpr>(existentialConstants);
}
private Graph<Implementation> BuildCallGraph() {
Graph<Implementation> callGraph = new Graph<Implementation>();
Dictionary<Procedure, HashSet<Implementation>> procToImpls = new Dictionary<Procedure, HashSet<Implementation>>();
foreach (Declaration decl in program.TopLevelDeclarations) {
Procedure proc = decl as Procedure;
if (proc == null) continue;
procToImpls[proc] = new HashSet<Implementation>();
}
foreach (Declaration decl in program.TopLevelDeclarations) {
Implementation impl = decl as Implementation;
if (impl == null || impl.SkipVerification) continue;
callGraph.AddSource(impl);
procToImpls[impl.Proc].Add(impl);
}
foreach (Declaration decl in program.TopLevelDeclarations) {
Implementation impl = decl as Implementation;
if (impl == null || impl.SkipVerification) continue;
foreach (Block b in impl.Blocks) {
foreach (Cmd c in b.Cmds) {
CallCmd cc = c as CallCmd;
if (cc == null) continue;
foreach (Implementation callee in procToImpls[cc.Proc]) {
callGraph.AddEdge(impl, callee);
}
}
}
}
return callGraph;
}
private WorkQueue BuildWorkList(Program program) {
// adding implementations to the workqueue from the bottom of the call graph upwards
WorkQueue queue = new WorkQueue();
StronglyConnectedComponents<Implementation> sccs =
new StronglyConnectedComponents<Implementation>(callGraph.Nodes,
new Adjacency<Implementation>(callGraph.Predecessors),
new Adjacency<Implementation>(callGraph.Successors));
sccs.Compute();
foreach (SCC<Implementation> scc in sccs) {
foreach (Implementation impl in scc) {
queue.Enqueue(impl);
}
}
return queue;
/*
Queue<Implementation> queue = new Queue<Implementation>();
foreach (Declaration decl in program.TopLevelDeclarations) {
Implementation impl = decl as Implementation;
if (impl == null || impl.SkipVerification) continue;
queue.Enqueue(impl);
}
return queue;
*/
}
private bool MatchCandidate(Expr boogieExpr, out string candidateConstant) {
candidateConstant = null;
IExpr antecedent;
IExpr expr = boogieExpr as IExpr;
if (expr != null && ExprUtil.Match(expr, Prop.Implies, out antecedent)) {
IdentifierExpr.ConstantFunApp constantFunApp = antecedent as IdentifierExpr.ConstantFunApp;
if (constantFunApp != null && houdiniConstants.ContainsKey(constantFunApp.IdentifierExpr.Name)) {
candidateConstant = constantFunApp.IdentifierExpr.Name;
return true;
}
}
return false;
}
private VCExpr BuildAxiom(Dictionary<string, bool> currentAssignment) {
DeclFreeProverContext proverContext = (DeclFreeProverContext)checker.TheoremProver.Context;
Boogie2VCExprTranslator exprTranslator = proverContext.BoogieExprTranslator;
VCExpressionGenerator exprGen = checker.VCExprGen;
VCExpr expr = VCExpressionGenerator.True;
foreach (KeyValuePair<string, bool> kv in currentAssignment) {
IdentifierExpr constantExpr;
houdiniConstants.TryGetValue(kv.Key, out constantExpr);
Contract.Assume(constantExpr != null);
VCExprVar exprVar = exprTranslator.LookupVariable(constantExpr.Decl);
if (kv.Value) {
expr = exprGen.And(expr, exprVar);
}
else {
expr = exprGen.And(expr, exprGen.Not(exprVar));
}
}
return expr;
}
private Dictionary<string, bool> BuildAssignment(Dictionary<string, IdentifierExpr>.KeyCollection constants) {
Dictionary<string, bool> initial = new Dictionary<string, bool>();
foreach (string constant in constants)
initial.Add(constant, true);
return initial;
}
private ProverInterface.Outcome VerifyUsingAxiom(HoudiniSession session, Implementation implementation, VCExpr axiom, out List<Counterexample> errors) {
if (vcgen == null)
throw new Exception("HdnVCGen not found for implementation: " + implementation.Name);
ProverInterface.Outcome outcome = TryCatchVerify(session, axiom, out errors);
return outcome;
}
// the main procedure that checks a procedure and updates the
// assignment and the worklist
private ProverInterface.Outcome HoudiniVerifyCurrent(
HoudiniSession session,
HoudiniState current,
Program program,
out List<Counterexample> errors,
out bool exc) {
if (current.Implementation == null)
throw new Exception("HoudiniVerifyCurrent has null implementation");
Implementation implementation = current.Implementation;
if (vcgen == null)
throw new Exception("HdnVCGen not found for implementation: " + implementation.Name);
ProverInterface.Outcome outcome = HoudiniVerifyCurrentAux(session, current, program, out errors, out exc);
return outcome;
}
private ProverInterface.Outcome VerifyCurrent(
HoudiniSession session,
HoudiniState current,
Program program,
out List<Counterexample> errors,
out bool exc) {
if (current.Implementation != null) {
Implementation implementation = current.Implementation;
if (vcgen == null)
throw new Exception("HdnVCGen not found for implementation: " + implementation.Name);
ProverInterface.Outcome outcome = TrySpinSameFunc(session, current, program, out errors, out exc);
return outcome;
}
else {
throw new Exception("VerifyCurrent has null implementation");
}
}
private bool IsOutcomeNotHoudini(ProverInterface.Outcome outcome, List<Counterexample> errors) {
switch (outcome) {
case ProverInterface.Outcome.Valid:
return false;
case ProverInterface.Outcome.Invalid:
Contract.Assume(errors != null);
foreach (Counterexample error in errors) {
if (ExtractRefutedAnnotation(error) == null)
return true;
}
return false;
default:
return true;
}
}
// returns true if at least one of the violations is non-candidate
private bool AnyNonCandidateViolation(ProverInterface.Outcome outcome, List<Counterexample> errors) {
switch (outcome) {
case ProverInterface.Outcome.Invalid:
Contract.Assert(errors != null);
foreach (Counterexample error in errors) {
if (ExtractRefutedAnnotation(error) == null)
return true;
}
return false;
default:
return false;
}
}
private List<Counterexample> emptyList = new List<Counterexample>();
// Record most current Non-Candidate errors found by Boogie, etc.
private void UpdateHoudiniOutcome(HoudiniOutcome houdiniOutcome,
Implementation implementation,
ProverInterface.Outcome verificationOutcome,
List<Counterexample> errors) {
string implName = implementation.ToString();
houdiniOutcome.implementationOutcomes.Remove(implName);
List<Counterexample> nonCandidateErrors = new List<Counterexample>();
switch (verificationOutcome) {
case ProverInterface.Outcome.Invalid:
Contract.Assume(errors != null);
foreach (Counterexample error in errors) {
if (ExtractRefutedAnnotation(error) == null)
nonCandidateErrors.Add(error);
}
break;
default:
break;
}
houdiniOutcome.implementationOutcomes.Add(implName, new VCGenOutcome(verificationOutcome, nonCandidateErrors));
}
private void FlushWorkList(HoudiniState current) {
this.NotifyFlushStart();
VCExpr axiom = BuildAxiom(current.Assignment);
while (current.WorkQueue.Count > 0) {
this.NotifyIteration();
current.Implementation = current.WorkQueue.Peek();
this.NotifyImplementation(current.Implementation);
HoudiniSession session;
houdiniSessions.TryGetValue(current.Implementation, out session);
List<Counterexample> errors;
ProverInterface.Outcome outcome = VerifyUsingAxiom(session, current.Implementation, axiom, out errors);
UpdateHoudiniOutcome(current.Outcome, current.Implementation, outcome, errors);
this.NotifyOutcome(outcome);
current.WorkQueue.Dequeue();
this.NotifyDequeue();
}
this.NotifyFlushFinish();
}
private void UpdateAssignment(HoudiniState current, RefutedAnnotation refAnnot) {
current.Assignment.Remove(refAnnot.Constant);
current.Assignment.Add(refAnnot.Constant, false);
this.NotifyConstant(refAnnot.Constant);
}
private void AddToWorkList(HoudiniState current, Implementation imp) {
if (!current.WorkQueue.Contains(imp) && !current.isBlackListed(imp.Name)) {
current.WorkQueue.Enqueue(imp);
this.NotifyEnqueue(imp);
}
}
private void UpdateWorkList(HoudiniState current,
ProverInterface.Outcome outcome,
List<Counterexample> errors) {
Contract.Assume(current.Implementation != null);
switch (outcome) {
case ProverInterface.Outcome.Valid:
current.WorkQueue.Dequeue();
this.NotifyDequeue();
break;
case ProverInterface.Outcome.Invalid:
Contract.Assume(errors != null);
bool dequeue = false;
foreach (Counterexample error in errors) {
RefutedAnnotation refutedAnnotation = ExtractRefutedAnnotation(error);
if (refutedAnnotation != null) {
foreach (Implementation implementation in FindImplementationsToEnqueue(refutedAnnotation, current.Implementation)) { AddToWorkList(current, implementation); }
UpdateAssignment(current, refutedAnnotation);
}
else {
dequeue = true; //once one non-houdini error is hit dequeue?!
}
}
if (dequeue) {
current.WorkQueue.Dequeue();
this.NotifyDequeue();
}
break;
case ProverInterface.Outcome.TimeOut:
// TODO: reset session instead of blocking timed out funcs?
current.addToBlackList(current.Implementation.Name);
current.WorkQueue.Dequeue();
this.NotifyDequeue();
break;
case ProverInterface.Outcome.OutOfMemory:
case ProverInterface.Outcome.Undetermined:
current.WorkQueue.Dequeue();
this.NotifyDequeue();
break;
default:
throw new Exception("Unknown vcgen outcome");
}
}
private void AddRelatedToWorkList(HoudiniState current, RefutedAnnotation refutedAnnotation) {
Contract.Assume(current.Implementation != null);
foreach (Implementation implementation in FindImplementationsToEnqueue(refutedAnnotation, current.Implementation)) {
AddToWorkList(current, implementation);
}
}
// Updates the worklist and current assignment
// @return true if the current function is kept on the queue
private bool UpdateAssignmentWorkList(HoudiniState current,
ProverInterface.Outcome outcome,
List<Counterexample> errors) {
Contract.Assume(current.Implementation != null);
bool dequeue = true;
switch (outcome) {
case ProverInterface.Outcome.Valid:
//yeah, dequeue
break;
case ProverInterface.Outcome.Invalid:
Contract.Assume(errors != null);
foreach (Counterexample error in errors) {
RefutedAnnotation refutedAnnotation = ExtractRefutedAnnotation(error);
if (refutedAnnotation != null) { // some candidate annotation removed
AddRelatedToWorkList(current, refutedAnnotation);
UpdateAssignment(current, refutedAnnotation);
dequeue = false;
}
}
break;
case ProverInterface.Outcome.TimeOut:
// TODO: reset session instead of blocking timed out funcs?
current.addToBlackList(current.Implementation.Name);
break;
case ProverInterface.Outcome.Undetermined:
case ProverInterface.Outcome.OutOfMemory:
break;
default:
throw new Exception("Unknown vcgen outcome");
}
if (dequeue) {
current.WorkQueue.Dequeue();
this.NotifyDequeue();
}
return !dequeue;
}
private class WorkQueue {
private Queue<Implementation> queue;
private HashSet<Implementation> set;
public WorkQueue() {
queue = new Queue<Implementation>();
set = new HashSet<Implementation>();
}
public void Enqueue(Implementation impl) {
if (set.Contains(impl))
return;
queue.Enqueue(impl);
set.Add(impl);
}
public Implementation Dequeue() {
Implementation impl = queue.Dequeue();
set.Remove(impl);
return impl;
}
public Implementation Peek() {
return queue.Peek();
}
public int Count {
get { return queue.Count; }
}
public bool Contains(Implementation impl) {
return set.Contains(impl);
}
}
private class HoudiniState {
private WorkQueue _workQueue;
private HashSet<string> blackList;
private Dictionary<string, bool> _assignment;
private Implementation _implementation;
private HoudiniOutcome _outcome;
public HoudiniState(WorkQueue workQueue, Dictionary<string, bool> currentAssignment) {
this._workQueue = workQueue;
this._assignment = currentAssignment;
this._implementation = null;
this._outcome = new HoudiniOutcome();
this.blackList = new HashSet<string>();
}
public WorkQueue WorkQueue {
get { return this._workQueue; }
}
public Dictionary<string, bool> Assignment {
get { return this._assignment; }
}
public Implementation Implementation {
get { return this._implementation; }
set { this._implementation = value; }
}
public HoudiniOutcome Outcome {
get { return this._outcome; }
}
public bool isBlackListed(string funcName) {
return blackList.Contains(funcName);
}
public void addToBlackList(string funcName) {
blackList.Add(funcName);
}
}
private void PrintBadList(string kind, List<string> list) {
if (list.Count != 0) {
Console.WriteLine("----------------------------------------");
Console.WriteLine("Functions: {0}", kind);
foreach (string fname in list) {
Console.WriteLine("\t{0}", fname);
}
Console.WriteLine("----------------------------------------");
}
}
private void PrintBadOutcomes(List<string> timeouts, List<string> inconc, List<string> errors) {
PrintBadList("TimedOut", timeouts);
PrintBadList("Inconclusive", inconc);
PrintBadList("Errors", errors);
}
public HoudiniOutcome VerifyProgram() {
HoudiniOutcome outcome = VerifyProgramSameFuncFirst();
PrintBadOutcomes(outcome.ListOfTimeouts, outcome.ListOfInconclusives, outcome.ListOfErrors);
return outcome;
}
// Old main loop
public HoudiniOutcome VerifyProgramUnorderedWork() {
HoudiniState current = new HoudiniState(BuildWorkList(program), BuildAssignment(houdiniConstants.Keys));
this.NotifyStart(program, houdiniConstants.Keys.Count);
while (current.WorkQueue.Count > 0) {
//System.GC.Collect();
this.NotifyIteration();
VCExpr axiom = BuildAxiom(current.Assignment);
this.NotifyAssignment(current.Assignment);
current.Implementation = current.WorkQueue.Peek();
this.NotifyImplementation(current.Implementation);
List<Counterexample> errors;
HoudiniSession session;
houdiniSessions.TryGetValue(current.Implementation, out session);
ProverInterface.Outcome outcome = VerifyUsingAxiom(session, current.Implementation, axiom, out errors);
this.NotifyOutcome(outcome);
UpdateHoudiniOutcome(current.Outcome, current.Implementation, outcome, errors);
if (IsOutcomeNotHoudini(outcome, errors) && !continueAtError) {
current.WorkQueue.Dequeue();
this.NotifyDequeue();
FlushWorkList(current);
}
else
UpdateWorkList(current, outcome, errors);
}
this.NotifyEnd(true);
current.Outcome.assignment = current.Assignment;
return current.Outcome;
}
// New main loop
public HoudiniOutcome VerifyProgramSameFuncFirst() {
HoudiniState current = new HoudiniState(BuildWorkList(program), BuildAssignment(houdiniConstants.Keys));
this.NotifyStart(program, houdiniConstants.Keys.Count);
while (current.WorkQueue.Count > 0) {
bool exceptional = false;
//System.GC.Collect();
this.NotifyIteration();
current.Implementation = current.WorkQueue.Peek();
this.NotifyImplementation(current.Implementation);
HoudiniSession session;
houdiniSessions.TryGetValue(current.Implementation, out session);
List<Counterexample> errors;
ProverInterface.Outcome outcome = VerifyCurrent(session, current, program, out errors, out exceptional);
// updates to worklist already done in VerifyCurrent, unless there was an exception
if (exceptional) {
this.NotifyOutcome(outcome);
UpdateHoudiniOutcome(current.Outcome, current.Implementation, outcome, errors);
if (IsOutcomeNotHoudini(outcome, errors) && !continueAtError) {
current.WorkQueue.Dequeue();
this.NotifyDequeue();
FlushWorkList(current);
}
else {
UpdateAssignmentWorkList(current, outcome, errors);
}
exceptional = false;
}
}
this.NotifyEnd(true);
current.Outcome.assignment = current.Assignment;
return current.Outcome;
}
//Clean houdini (Based on "Houdini Spec in Boogie" email 10/22/08
//Aborts when there is a violation of non-candidate assertion
//This can be used in eager mode (continueAfterError) by simply making
//all non-candidate annotations as unchecked (free requires/ensures, assumes)
public HoudiniOutcome PerformHoudiniInference() {
HoudiniState current = new HoudiniState(BuildWorkList(program), BuildAssignment(houdiniConstants.Keys));
this.NotifyStart(program, houdiniConstants.Keys.Count);
while (current.WorkQueue.Count > 0) {
bool exceptional = false;
//System.GC.Collect();
this.NotifyIteration();
current.Implementation = current.WorkQueue.Peek();
this.NotifyImplementation(current.Implementation);
List<Counterexample> errors;
HoudiniSession session;
this.houdiniSessions.TryGetValue(current.Implementation, out session);
ProverInterface.Outcome outcome = HoudiniVerifyCurrent(session, current, program, out errors, out exceptional);
// updates to worklist already done in VerifyCurrent, unless there was an exception
if (exceptional) {
this.NotifyOutcome(outcome);
UpdateHoudiniOutcome(current.Outcome, current.Implementation, outcome, errors);
if (AnyNonCandidateViolation(outcome, errors)) { //abort
current.WorkQueue.Dequeue();
this.NotifyDequeue();
FlushWorkList(current);
}
else { //continue
UpdateAssignmentWorkList(current, outcome, errors);
}
}
}
this.NotifyEnd(true);
current.Outcome.assignment = current.Assignment;
return current.Outcome;
}
private List<Implementation> FindImplementationsToEnqueue(RefutedAnnotation refutedAnnotation, Implementation currentImplementation) {
List<Implementation> implementations = new List<Implementation>();
switch (refutedAnnotation.Kind) {
case RefutedAnnotationKind.REQUIRES:
foreach (Implementation callee in callGraph.Successors(currentImplementation)) {
Contract.Assume(callee.Proc != null);
if (callee.Proc.Equals(refutedAnnotation.CalleeProc))
implementations.Add(callee);
}
break;
case RefutedAnnotationKind.ENSURES:
foreach (Implementation caller in callGraph.Predecessors(currentImplementation))
implementations.Add(caller);
break;
case RefutedAnnotationKind.ASSERT: //the implementation is already in queue
break;
default:
throw new Exception("Unknown Refuted annotation kind:" + refutedAnnotation.Kind);
}
return implementations;
}
private enum RefutedAnnotationKind { REQUIRES, ENSURES, ASSERT };
private class RefutedAnnotation {
private string _constant;
private RefutedAnnotationKind _kind;
private Procedure _callee;
private RefutedAnnotation(string constant, RefutedAnnotationKind kind, Procedure callee) {
this._constant = constant;
this._kind = kind;
this._callee = callee;
}
public RefutedAnnotationKind Kind {
get { return this._kind; }
}
public string Constant {
get { return this._constant; }
}
public Procedure CalleeProc {
get { return this._callee; }
}
public static RefutedAnnotation BuildRefutedRequires(string constant, Procedure callee) {
return new RefutedAnnotation(constant, RefutedAnnotationKind.REQUIRES, callee);
}
public static RefutedAnnotation BuildRefutedEnsures(string constant) {
return new RefutedAnnotation(constant, RefutedAnnotationKind.ENSURES, null);
}
public static RefutedAnnotation BuildRefutedAssert(string constant) {
return new RefutedAnnotation(constant, RefutedAnnotationKind.ASSERT, null);
}
}
private void PrintRefutedCall(CallCounterexample err, XmlSink xmlOut) {
Expr cond = err.FailingRequires.Condition;
string houdiniConst;
if (MatchCandidate(cond, out houdiniConst)) {
xmlOut.WriteError("precondition violation", err.FailingCall.tok, err.FailingRequires.tok, err.Trace);
}
}
private void PrintRefutedReturn(ReturnCounterexample err, XmlSink xmlOut) {
Expr cond = err.FailingEnsures.Condition;
string houdiniConst;
if (MatchCandidate(cond, out houdiniConst)) {
xmlOut.WriteError("postcondition violation", err.FailingReturn.tok, err.FailingEnsures.tok, err.Trace);
}
}
private void PrintRefutedAssert(AssertCounterexample err, XmlSink xmlOut) {
Expr cond = err.FailingAssert.OrigExpr;
string houdiniConst;
if (MatchCandidate(cond, out houdiniConst)) {
xmlOut.WriteError("postcondition violation", err.FailingAssert.tok, err.FailingAssert.tok, err.Trace);
}
}
private void DebugRefutedCandidates(Implementation curFunc, List<Counterexample> errors) {
XmlSink xmlRefuted = CommandLineOptions.Clo.XmlRefuted;
if (xmlRefuted != null && errors != null) {
DateTime start = DateTime.Now;
xmlRefuted.WriteStartMethod(curFunc.ToString(), start);
foreach (Counterexample error in errors) {
CallCounterexample ce = error as CallCounterexample;
if (ce != null) PrintRefutedCall(ce, xmlRefuted);
ReturnCounterexample re = error as ReturnCounterexample;
if (re != null) PrintRefutedReturn(re, xmlRefuted);
AssertCounterexample ae = error as AssertCounterexample;
if (ae != null) PrintRefutedAssert(ae, xmlRefuted);
}
DateTime end = DateTime.Now;
xmlRefuted.WriteEndMethod("errors", end, end.Subtract(start));
}
}
private RefutedAnnotation ExtractRefutedAnnotation(Counterexample error) {
string houdiniConstant;
CallCounterexample callCounterexample = error as CallCounterexample;
if (callCounterexample != null) {
Procedure failingProcedure = callCounterexample.FailingCall.Proc;
Requires failingRequires = callCounterexample.FailingRequires;
if (MatchCandidate(failingRequires.Condition, out houdiniConstant)) {
Contract.Assert(houdiniConstant != null);
return RefutedAnnotation.BuildRefutedRequires(houdiniConstant, failingProcedure);
}
}
ReturnCounterexample returnCounterexample = error as ReturnCounterexample;
if (returnCounterexample != null) {
Ensures failingEnsures = returnCounterexample.FailingEnsures;
if (MatchCandidate(failingEnsures.Condition, out houdiniConstant)) {
Contract.Assert(houdiniConstant != null);
return RefutedAnnotation.BuildRefutedEnsures(houdiniConstant);
}
}
AssertCounterexample assertCounterexample = error as AssertCounterexample;
if (assertCounterexample != null) {
AssertCmd failingAssert = assertCounterexample.FailingAssert;
if (MatchCandidate(failingAssert.OrigExpr, out houdiniConstant)) {
Contract.Assert(houdiniConstant != null);
return RefutedAnnotation.BuildRefutedAssert(houdiniConstant);
}
}
return null;
}
private ProverInterface.Outcome TryCatchVerify(HoudiniSession session, VCExpr axiom, out List<Counterexample> errors) {
ProverInterface.Outcome outcome;
try {
outcome = session.Verify(checker, axiom, out errors);
}
catch (VCGenException e) {
Contract.Assume(e != null);
errors = null;
outcome = ProverInterface.Outcome.Undetermined;
}
catch (UnexpectedProverOutputException upo) {
Contract.Assume(upo != null);
errors = null;
outcome = ProverInterface.Outcome.Undetermined;
}
return outcome;
}
//version of TryCatchVerify that spins on the same function
//as long as the current assignment is changing
private ProverInterface.Outcome TrySpinSameFunc(
HoudiniSession session,
HoudiniState current,
Program program,
out List<Counterexample> errors,
out bool exceptional) {
Contract.Assert(current.Implementation != null);
ProverInterface.Outcome outcome;
errors = null;
outcome = ProverInterface.Outcome.Undetermined;
try {
bool trySameFunc = true;
bool pastFirstIter = false; //see if this new loop is even helping
do {
if (pastFirstIter) {
//System.GC.Collect();
this.NotifyIteration();
}
VCExpr currentAx = BuildAxiom(current.Assignment);
this.NotifyAssignment(current.Assignment);
outcome = session.Verify(checker, currentAx, out errors);
this.NotifyOutcome(outcome);
DebugRefutedCandidates(current.Implementation, errors);
UpdateHoudiniOutcome(current.Outcome, current.Implementation, outcome, errors);
if (!continueAtError && IsOutcomeNotHoudini(outcome, errors)) {
current.WorkQueue.Dequeue();
this.NotifyDequeue();
trySameFunc = false;
FlushWorkList(current);
}
else {
trySameFunc = UpdateAssignmentWorkList(current, outcome, errors);
//reset for the next round
errors = null;
outcome = ProverInterface.Outcome.Undetermined;
}
pastFirstIter = true;
} while (trySameFunc && current.WorkQueue.Count > 0);
}
catch (VCGenException e) {
Contract.Assume(e != null);
NotifyException("VCGen");
exceptional = true;
return outcome;
}
catch (UnexpectedProverOutputException upo) {
Contract.Assume(upo != null);
NotifyException("UnexpectedProverOutput");
exceptional = true;
return outcome;
}
exceptional = false;
return outcome;
}
//Similar to TrySpinSameFunc except no Candidate logic
private ProverInterface.Outcome HoudiniVerifyCurrentAux(
HoudiniSession session,
HoudiniState current,
Program program,
out List<Counterexample> errors,
out bool exceptional) {
Contract.Assert(current.Implementation != null);
ProverInterface.Outcome outcome;
// the following initialization is there just to satisfy the compiler
// which apparently does not understand the semantics of do-while statements
errors = null;
outcome = ProverInterface.Outcome.Undetermined;
try {
bool trySameFunc = true;
bool pastFirstIter = false; //see if this new loop is even helping
do {
errors = null;
outcome = ProverInterface.Outcome.Undetermined;
if (pastFirstIter) {
//System.GC.Collect();
this.NotifyIteration();
}
VCExpr currentAx = BuildAxiom(current.Assignment);
this.NotifyAssignment(current.Assignment);
//check the VC with the current assignment
outcome = session.Verify(checker, currentAx, out errors);
this.NotifyOutcome(outcome);
DebugRefutedCandidates(current.Implementation, errors);
UpdateHoudiniOutcome(current.Outcome, current.Implementation, outcome, errors);
if (AnyNonCandidateViolation(outcome, errors)) { //abort
current.WorkQueue.Dequeue();
this.NotifyDequeue();
trySameFunc = false;
FlushWorkList(current);
}
else { //continue
trySameFunc = UpdateAssignmentWorkList(current, outcome, errors);
}
pastFirstIter = true;
} while (trySameFunc && current.WorkQueue.Count > 0);
}
catch (VCGenException e) {
Contract.Assume(e != null);
NotifyException("VCGen");
exceptional = true;
return outcome;
}
catch (UnexpectedProverOutputException upo) {
Contract.Assume(upo != null);
NotifyException("UnexpectedProverOutput");
exceptional = true;
return outcome;
}
exceptional = false;
return outcome;
}
}
public enum HoudiniOutcomeKind { Done, FatalError, VerificationCompleted }
public class VCGenOutcome {
public ProverInterface.Outcome outcome;
public List<Counterexample> errors;
public VCGenOutcome(ProverInterface.Outcome outcome, List<Counterexample> errors) {
this.outcome = outcome;
this.errors = errors;
}
}
public class HoudiniOutcome {
// final assignment
public Dictionary<string, bool> assignment = new Dictionary<string, bool>();
// boogie errors
public Dictionary<string, VCGenOutcome> implementationOutcomes = new Dictionary<string, VCGenOutcome>();
// outcome kind
public HoudiniOutcomeKind kind;
// statistics
private int CountResults(ProverInterface.Outcome outcome) {
int outcomeCount = 0;
foreach (VCGenOutcome verifyOutcome in implementationOutcomes.Values) {
if (verifyOutcome.outcome == outcome)
outcomeCount++;
}
return outcomeCount;
}
private List<string> ListOutcomeMatches(ProverInterface.Outcome outcome) {
List<string> result = new List<string>();
foreach (KeyValuePair<string, VCGenOutcome> kvpair in implementationOutcomes) {
if (kvpair.Value.outcome == outcome)
result.Add(kvpair.Key);
}
return result;
}
public int ErrorCount {
get {
return CountResults(ProverInterface.Outcome.Invalid);
}
}
public int Verified {
get {
return CountResults(ProverInterface.Outcome.Valid);
}
}
public int Inconclusives {
get {
return CountResults(ProverInterface.Outcome.Undetermined);
}
}
public int TimeOuts {
get {
return CountResults(ProverInterface.Outcome.TimeOut);
}
}
public List<string> ListOfTimeouts {
get {
return ListOutcomeMatches(ProverInterface.Outcome.TimeOut);
}
}
public List<string> ListOfInconclusives {
get {
return ListOutcomeMatches(ProverInterface.Outcome.Undetermined);
}
}
public List<string> ListOfErrors {
get {
return ListOutcomeMatches(ProverInterface.Outcome.Invalid);
}
}
}
}
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