private AbstractStackState <VariabilityInfo> HandleLdloc(ILInstruction ili, AbstractStackState <VariabilityInfo> pre, int index)
{
Contract.Requires <ArgumentNullException>(pre != null);
Contract.Requires <ArgumentException>(index >= 0);
return(pre.Push(pre.GetLocal(index)).UniqueSuccessor());
}
private AbstractStackState <VariabilityInfo> HandleNewarr(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
return(pre
.Pop()
.Push(VariabilityInfo.CreateBySingleDef(EVariability.ExternVariable, ili.Index))
.UniqueSuccessor());
}
protected override bool Merge(
AbstractStackState <VariabilityInfo> a,
AbstractStackState <VariabilityInfo> b,
out AbstractStackState <VariabilityInfo> m)
{
List <VariabilityInfo> stack = new List <VariabilityInfo>();
bool changed = Merge(i => a[i], i => b[i], stack, a.Depth);
List <VariabilityInfo> locals = new List <VariabilityInfo>();
if (Merge(i => a.GetLocal(i), i => b.GetLocal(i), locals, a.NumLocals))
{
changed = true;
}
List <VariabilityInfo> args = new List <VariabilityInfo>();
if (Merge(i => a.GetArgument(i), i => b.GetArgument(i), args, a.NumArguments))
{
changed = true;
}
if (a.HasUniqueSuccessor() != b.HasUniqueSuccessor())
{
changed = true;
}
m = new IndependentStackState(stack, locals, args,
a.HasUniqueSuccessor() && b.HasUniqueSuccessor());
return(changed);
}
private AbstractStackState <VariabilityInfo> HandleStind(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
VariabilityInfo value = pre[0];
VariabilityInfo address = pre[1];
return(UpdateStackState(ili, value, pre).Pop().Pop().UniqueSuccessor());
}
private AbstractStackState <VariabilityInfo> HandleBinOp(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
VariabilityInfo a = pre[0];
VariabilityInfo b = pre[1];
VariabilityInfo r = VariabilityInfo.MergeByNewDef(a, b, ili.Index);
return(pre.Pop().Pop().Push(r).UniqueSuccessor());
}
private AbstractStackState <VariabilityInfo> HandleCpobj(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
VariabilityInfo source = pre[0];
VariabilityInfo dest = pre[1];
AbstractStackState <VariabilityInfo> next = UpdateStackState(ili, source, pre);
next = next.Pop().Pop();
return(next.UniqueSuccessor());
}
/// <summary>
/// Constructs a stack state indicating a non-unique successor, based on an existing state
/// </summary>
/// <param name="state">a stack state</param>
/// <returns>the desired stack state</returns>
public static AbstractStackState <VariabilityInfo> AmbiguousSuccessor(this AbstractStackState <VariabilityInfo> state)
{
if (HasUniqueSuccessor(state))
{
return(new ModifyUniqueSuccessorStackState(state, false));
}
else
{
return(state);
}
}
/// <summary>
/// Constructs a stack state indicating a unique successor, based on an existing stat6e
/// </summary>
/// <param name="state">a stack state</param>
/// <returns>the desired stack state</returns>
public static AbstractStackState <VariabilityInfo> UniqueSuccessor(this AbstractStackState <VariabilityInfo> state)
{
if (!HasUniqueSuccessor(state))
{
return(new ModifyUniqueSuccessorStackState(state, true));
}
else
{
return(state);
}
}
/// <summary>
/// Propagates a stack state by computing the effects of executing a specific instruction.
/// </summary>
/// <param name="ili"></param>
/// <param name="pre"></param>
/// <returns></returns>
protected virtual AbstractStackState <TElem> Propagate(ILInstruction ili, AbstractStackState <TElem> pre)
{
int preDepth = pre.Depth;
AbstractStackState <TElem> post = _pmap[ili.Code](ili, pre);
int postDepth = post.Depth;
int npush, npop;
StackInfluenceAnalysis.GetStackBilance(ili, Method, out npop, out npush);
Debug.Assert(postDepth - preDepth == npush - npop);
return(post);
}
private AbstractStackState <VariabilityInfo> HandleLdsfld(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
FieldInfo field = (FieldInfo)ili.Operand;
FieldFacts fieldFacts = FactUniverse.Instance.GetFacts(field);
EVariability fieldVar = fieldFacts.IsWritten || fieldFacts.IsSubMutated ?
EVariability.ExternVariable : EVariability.Constant;
VariabilityInfo newVar = VariabilityInfo.CreateBySingleDef(fieldVar, ili.Index);
return(pre
.Push(newVar)
.UniqueSuccessor());
}
/// <summary>
/// Tells whether a given stack state has a unique successor
/// </summary>
/// <param name="state">stack state</param>
/// <returns>whether stack state has a unique successor</returns>
public static bool HasUniqueSuccessor(this AbstractStackState <VariabilityInfo> state)
{
IUniqueSuccessorInfo vstate = state as IUniqueSuccessorInfo;
while (vstate == null)
{
DependentStackState <VariabilityInfo> dstate = (DependentStackState <VariabilityInfo>)state;
state = dstate.Pre;
vstate = state as IUniqueSuccessorInfo;
}
return(vstate.HasUniqueSuccessor);
}
private AbstractStackState <VariabilityInfo> HandleRet(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
Type returnType;
if (Method.IsFunction(out returnType))
{
return(pre.Pop().UniqueSuccessor());
}
else
{
return(pre.UniqueSuccessor());
}
}
protected override bool Merge(AbstractStackState <TElem> a, AbstractStackState <TElem> b, out AbstractStackState <TElem> m)
{
Contract.Requires(a != null);
Contract.Requires(b != null);
Contract.Requires(a.Depth == b.Depth);
Contract.Requires(a.NumLocals == b.NumLocals);
Contract.Requires(a.NumArguments == b.NumArguments);
Contract.Ensures(Contract.ValueAtReturn(out m) != null);
m = null; //so that Code Contracts can be deactivated completely, otherwise the Compiler complains that m is unassigned on return
return(false);
}
private AbstractStackState <VariabilityInfo> HandleNewobj(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
ConstructorInfo ctor = (ConstructorInfo)ili.Operand;
ParameterInfo[] args = ctor.GetParameters();
AbstractStackState <VariabilityInfo> next = pre;
for (int i = 0; i < args.Length; i++)
{
next = next.Pop();
}
return(next
.Push(VariabilityInfo.CreateBySingleDef(EVariability.ExternVariable, ili.Index))
.UniqueSuccessor());
}
private AbstractStackState <VariabilityInfo> HandleStfld(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
var field = (FieldInfo)ili.Operand;
int index = Array.IndexOf(_localizedFields, field);
if (index < 0)
{
return(Pop2(ili, pre));
}
else
{
VariabilityInfo value = pre[0];
return(pre.Assign(index + _localizedFieldsBaseIndex, value).Pop().Pop().UniqueSuccessor());
}
}
/// <summary>
/// Executes the analysis.
/// </summary>
public virtual void Run()
{
Contract.Requires(!AnalysisDone);
Contract.Ensures(AnalysisDone);
MethodFacts myFacts = FactUniverse.Instance.GetFacts(Method);
CFG = myFacts.CFG;
_stackStates = new AbstractStackState <TElem> [CFG.Instructions.Count];
AbstractStackState <TElem> initial = CreateInitialStackState();
Queue <Tuple <AbstractStackState <TElem>, ILInstruction> > q = new Queue <Tuple <AbstractStackState <TElem>, ILInstruction> >();
q.Enqueue(Tuple.Create(initial, CFG.Instructions[0]));
int marshal = CFG.Instructions.Count - 1;
while (q.Count > 0)
{
Tuple <AbstractStackState <TElem>, ILInstruction> cur = q.Dequeue();
AbstractStackState <TElem> preState = cur.Item1;
ILInstruction ili = cur.Item2;
AbstractStackState <TElem> nextState = Propagate(ili, preState);
ILInstruction[] succs = CFG.GetSuccessorsOf(ili);
if (_stackStates[ili.Index] == null)
{
_stackStates[ili.Index] = nextState;
}
else
{
bool changed = Merge(_stackStates[ili.Index], nextState, out _stackStates[ili.Index]);
if (!changed)
{
continue;
}
}
foreach (ILInstruction nextILI in succs)
{
if (nextILI.Index < marshal) // skip pseudo ret at the end
{
q.Enqueue(Tuple.Create(_stackStates[ili.Index], nextILI));
}
}
}
AnalysisDone = true;
}
private AbstractStackState <VariabilityInfo> HandleCall(ILInstruction ili, AbstractStackState <VariabilityInfo> pre, bool isCalli)
{
MethodBase callee = (MethodBase)ili.Operand;
bool hasThis = callee.CallingConvention.HasFlag(CallingConventions.HasThis);
EVariability callVar = EVariability.Constant;
ParameterInfo[] args = callee.GetParameters();
MethodFacts myFacts = FactUniverse.Instance.GetFacts(Method);
MethodFacts calleeFacts = FactUniverse.Instance.GetFacts(callee);
AbstractStackState <VariabilityInfo> next = pre;
if (hasThis)
{
callVar = VariabilityOperations.Stronger(callVar, pre[0].Variability);
next = pre.Pop();
}
for (int i = 0; i < args.Length; i++)
{
callVar = VariabilityOperations.Stronger(callVar, next[0].Variability);
next = next.Pop();
}
if (!calleeFacts.IsSideEffectFree)
{
callVar = EVariability.ExternVariable;
}
if (calleeFacts.IsStaticEvaluation)
{
callVar = EVariability.Constant;
}
if (isCalli)
{
next = pre.Pop();
}
VariabilityInfo callVarI = VariabilityInfo.CreateBySingleDef(callVar, ili.Index);
next = UpdateStackState(ili, callVarI, next);
Type returnType;
if (callee.IsFunction(out returnType))
{
next = next.Push(callVarI);
}
return(next.UniqueSuccessor());
}
private AbstractStackState <VariabilityInfo> HandleLdfld(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
FieldInfo field = (FieldInfo)ili.Operand;
int index = Array.IndexOf(_localizedFields, field);
if (index >= 0)
{
return(HandleLdloc(null, pre.Pop(), _localizedFieldsBaseIndex + index));
}
else
{
FieldFacts fieldFacts = FactUniverse.Instance.GetFacts(field);
EVariability fieldVar = fieldFacts.IsWritten || fieldFacts.IsSubMutated ?
EVariability.ExternVariable : EVariability.Constant;
VariabilityInfo newVar = VariabilityInfo.CreateBySingleDef(fieldVar, ili.Index);
return(pre
.Pop()
.Push(newVar)
.UniqueSuccessor());
}
}
private AbstractStackState <VariabilityInfo> HandleStloc(ILInstruction ili, AbstractStackState <VariabilityInfo> pre, int index)
{
VariabilityInfo value = pre[0];
return(pre.Assign(index, value).Pop().UniqueSuccessor());
}
/// <summary>
/// Constructs a new stack state based on an existing state
/// </summary>
/// <param name="pre">existing state</param>
/// <param name="isUnique">whether that state has a unique successor</param>
public ModifyUniqueSuccessorStackState(AbstractStackState <VariabilityInfo> pre, bool isUnique) :
base(pre)
{
HasUniqueSuccessor = isUnique;
}
private AbstractStackState <VariabilityInfo> HandleBinBranch(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
VariabilityInfo a = pre[0];
VariabilityInfo b = pre[1];
var next = pre.Pop().Pop();
if (VariabilityOperations.Stronger(a.Variability, b.Variability) == EVariability.Constant)
{
next = next.UniqueSuccessor();
}
else
{
next = next.AmbiguousSuccessor();
}
return(next);
}
private AbstractStackState <VariabilityInfo> HandleStarg(ILInstruction ili, AbstractStackState <VariabilityInfo> pre, int index)
{
return(pre.AssignArg(index, pre[0]).Pop().UniqueSuccessor());
}
private AbstractStackState <VariabilityInfo> HandleUnBranch(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
VariabilityInfo c = pre[0];
var next = pre.Pop();
if (c.Variability == EVariability.Constant)
{
next = next.UniqueSuccessor();
}
else
{
next = next.AmbiguousSuccessor();
}
return(next);
}
private AbstractStackState <VariabilityInfo> PushC(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
return(pre.Push(VariabilityInfo.CreateBySingleDef(EVariability.Constant, ili.Index)).UniqueSuccessor());
}
private AbstractStackState <VariabilityInfo> Nop(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
return(pre.UniqueSuccessor());
}
private AbstractStackState <VariabilityInfo> UpdateStackState(ILInstruction ili, VariabilityInfo newVar, AbstractStackState <VariabilityInfo> cur)
{
MethodFacts myFacts = FactUniverse.Instance.GetFacts(Method);
foreach (LocalMutation lm in myFacts.GetLocalMutations(ili.Index))
{
IModifiesStackState mss = lm as IModifiesStackState;
if (mss != null)
{
cur = mss.ModifyStackState(cur, newVar, VariabilityInfo.MergeDefs);
}
}
return(cur);
}
/// <summary>
/// Merges two stack states.
/// </summary>
/// <remarks>Merging stack states is necessary wherever program flow joins.</remarks>
/// <param name="a">a stack state</param>
/// <param name="b">another stack state</param>
/// <param name="m">the merged stack state</param>
/// <returns>false iff m and a are equivalent in a problem-specific sense.</returns>
protected abstract bool Merge(
AbstractStackState <TElem> a,
AbstractStackState <TElem> b,
out AbstractStackState <TElem> m);
private AbstractStackState <VariabilityInfo> HandleLdind(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
return(PushV(ili, pre.Pop()));
}
private AbstractStackState <VariabilityInfo> HandleLdArg(ILInstruction ili, int narg, AbstractStackState <VariabilityInfo> pre)
{
MethodFacts myFacts = FactUniverse.Instance.GetFacts(Method);
EVariability varia;
if (Method.CallingConvention.HasFlag(CallingConventions.HasThis))
{
if (narg == 0)
{
varia = EVariability.Constant;
}
else
{
varia = _callPattern.Pattern[narg - 1];
}
}
else
{
varia = _callPattern.Pattern[narg];
}
return(pre.Push(VariabilityInfo.CreateBySingleDef(varia, ili.Index)).UniqueSuccessor());
}
private AbstractStackState <VariabilityInfo> HandleDup(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
return(pre.Push(pre[0]).UniqueSuccessor());
}
