/// <summary>
/// Return the common parent of the two expressions, and indicate if the expressions overlap
/// </summary>
/// <param name="eb1"></param>
/// <param name="eb2"></param>
/// <returns></returns>
/// <remarks>
/// When finding the common parent, we want to preserve any array slicing. Indexing brackets are not removed if present in both expressions.
/// Mismatching indices are replaced by AnyIndex.
/// Examples:
/// i = loop index inside the gate block
/// j = loop index outside the gate block, or a method parameter
/// (a,a[i]) => (a,true)
/// (a,a[j]) => (a,true)
/// (a[i],a[0]) => (a[*],true)
/// (a[i],a[j]) => (a[*],true)
/// (a[j],a[0]) => (a[*],assumeMatch)
/// (a[0],a[1]) => (a[*],false)
/// (a[0][0],a[1][0]) => (a[*][0],false)
/// (a[0][0],a[1][1]) => (a[*][*],false)
/// </remarks>
private static ExpressionWithBindings GetCommonParent(ExpressionWithBindings eb1, ExpressionWithBindings eb2)
{
List <IExpression> prefixes1 = Recognizer.GetAllPrefixes(eb1.Expression);
List <IExpression> prefixes2 = Recognizer.GetAllPrefixes(eb2.Expression);
if (!prefixes1[0].Equals(prefixes2[0]))
{
throw new Exception("Expressions have no overlap: " + eb1 + "," + eb2);
}
IExpression parent = prefixes1[0];
int count = System.Math.Min(prefixes1.Count, prefixes2.Count);
for (int i = 1; i < count; i++)
{
IExpression prefix1 = prefixes1[i];
IExpression prefix2 = prefixes2[i];
if (prefix1 is IArrayIndexerExpression)
{
IArrayIndexerExpression iaie1 = (IArrayIndexerExpression)prefix1;
if (prefix2 is IArrayIndexerExpression)
{
IArrayIndexerExpression iaie2 = (IArrayIndexerExpression)prefix2;
if (iaie1.Indices.Count != iaie2.Indices.Count)
{
throw new Exception("Array rank mismatch: " + eb1 + "," + eb2);
}
IList <IExpression> indices = Builder.ExprCollection();
for (int ind = 0; ind < iaie1.Indices.Count; ind++)
{
IExpression index1 = iaie1.Indices[ind];
IExpression index2 = iaie2.Indices[ind];
IExpression index = Unify(index1, eb1.Bindings, index2, eb2.Bindings);
indices.Add(index);
}
parent = Builder.ArrayIndex(parent, indices);
}
else
{
break;
}
}
else
{
throw new Exception("Unhandled expression type: " + prefix1);
}
}
ExpressionWithBindings result = new ExpressionWithBindings();
result.Expression = parent;
if (eb1.Bindings.Count > 0 && eb2.Bindings.Count > 0)
{
result.Bindings.AddRange(eb1.Bindings);
result.Bindings.AddRange(eb2.Bindings);
}
return(result);
}
private void RemoveUsesOfDefs(GateBlock gateBlock)
{
foreach (KeyValuePair <IVariableDeclaration, ExpressionWithBindings> entry in gateBlock.variablesDefined)
{
IVariableDeclaration ivd = entry.Key;
ExpressionWithBindings eb = entry.Value;
if (gateBlock.variablesUsed.TryGetValue(ivd, out List <ExpressionWithBindings> ebs))
{
List <ExpressionWithBindings> keep = new List <ExpressionWithBindings>();
foreach (ExpressionWithBindings eb2 in ebs)
{
if (!CouldOverlap(eb, eb2))
{
keep.Add(eb2);
}
}
gateBlock.variablesUsed[ivd] = keep;
}
}
}
internal static bool CouldOverlap(ExpressionWithBindings eb1, ExpressionWithBindings eb2)
{
var emptyBindings = (IEnumerable <IReadOnlyCollection <ConditionBinding> >) new[] { new ConditionBinding[0] };
IEnumerable <IReadOnlyCollection <ConditionBinding> > bindings1 = (eb1.Bindings.Count > 0) ?
eb1.Bindings : emptyBindings;
IEnumerable <IReadOnlyCollection <ConditionBinding> > bindings2 = (eb2.Bindings.Count > 0) ?
eb2.Bindings : emptyBindings;
foreach (IReadOnlyCollection <ConditionBinding> binding1 in bindings1)
{
foreach (IReadOnlyCollection <ConditionBinding> binding2 in bindings2)
{
// TODO: investigate whether we need to provide local var predicate.
if (Recognizer.MutatingFirstAffectsSecond(eb1.Expression, eb2.Expression, binding1, binding2, ivd => false))
{
return(true);
}
}
}
return(false);
}
/// <summary>
/// Add expr to currentBlock.variablesDefined or currentBlock.variablesUsed
/// </summary>
/// <param name="expr"></param>
/// <param name="isDef"></param>
/// <param name="conditionContext"></param>
protected void ProcessUse(IExpression expr, bool isDef, List <ConditionBinding> conditionContext)
{
IVariableDeclaration ivd = Recognizer.GetVariableDeclaration(expr);
if (ivd == null)
{
return;
}
if (!CodeRecognizer.IsStochastic(context, ivd))
{
return;
}
if (gateBlockContext.Count == 0)
{
return;
}
GateBlock currentBlock = gateBlockContext[gateBlockContext.Count - 1];
GateBlock gateBlockOfVar = context.InputAttributes.Get <GateBlock>(ivd);
if (gateBlockOfVar == currentBlock)
{
return; // local variable of the gateBlock
}
ExpressionWithBindings eb = new ExpressionWithBindings();
eb.Expression = ReplaceLocalIndices(currentBlock, expr);
List <ConditionBinding> bindings = FilterConditionContext(currentBlock, conditionContext);
if (bindings.Count > 0)
{
eb.Bindings.Add(bindings);
}
//eb.Containers = Containers.InsideOf(context, GetAncestorIndexOfGateBlock(currentBlock));
if (isDef)
{
ExpressionWithBindings eb2;
if (!currentBlock.variablesDefined.TryGetValue(ivd, out eb2))
{
currentBlock.variablesDefined[ivd] = eb;
}
else
{
// all definitions of the same variable must have a common parent
currentBlock.variablesDefined[ivd] = GetCommonParent(eb, eb2);
}
}
else
{
List <ExpressionWithBindings> ebs;
if (!currentBlock.variablesUsed.TryGetValue(ivd, out ebs))
{
ebs = new List <ExpressionWithBindings>();
ebs.Add(eb);
currentBlock.variablesUsed[ivd] = ebs;
}
else
{
// collect all uses that overlap with eb, and replace with their common parent
List <ExpressionWithBindings> notOverlapping = new List <ExpressionWithBindings>();
while (true)
{
foreach (ExpressionWithBindings eb2 in ebs)
{
ExpressionWithBindings parent = GetCommonParent(eb, eb2);
if (CouldOverlap(eb, eb2))
{
eb = parent;
}
else
{
notOverlapping.Add(eb2);
}
}
if (notOverlapping.Count == ebs.Count)
{
break; // nothing overlaps
}
// eb must have changed, so try again using the new eb
ebs.Clear();
ebs.AddRange(notOverlapping);
notOverlapping.Clear();
}
ebs.Add(eb);
currentBlock.variablesUsed[ivd] = ebs;
}
}
}
/// <summary>
/// Return the common parent of the two expressions, and indicate if the expressions overlap
/// </summary>
/// <param name="eb1"></param>
/// <param name="eb2"></param>
/// <returns></returns>
/// <remarks>
/// When finding the common parent, we want to preserve any array slicing. Indexing brackets are not removed if present in both expressions.
/// Mismatching indices are replaced by AnyIndex.
/// Examples:
/// i = loop index inside the gate block
/// j = loop index outside the gate block, or a method parameter
/// (a,a[i]) => (a,true)
/// (a,a[j]) => (a,true)
/// (a[i],a[0]) => (a[*],true)
/// (a[i],a[j]) => (a[*],true)
/// (a[j],a[0]) => (a[*],assumeMatch)
/// (a[0],a[1]) => (a[*],false)
/// (a[0][0],a[1][0]) => (a[*][0],false)
/// (a[0][0],a[1][1]) => (a[*][*],false)
/// </remarks>
private static ExpressionWithBindings GetCommonParent(ExpressionWithBindings eb1, ExpressionWithBindings eb2)
{
List <IExpression> prefixes1 = Recognizer.GetAllPrefixes(eb1.Expression);
List <IExpression> prefixes2 = Recognizer.GetAllPrefixes(eb2.Expression);
if (!prefixes1[0].Equals(prefixes2[0]))
{
throw new Exception("Expressions have no overlap: " + eb1 + "," + eb2);
}
IExpression parent = prefixes1[0];
int count = System.Math.Min(prefixes1.Count, prefixes2.Count);
for (int i = 1; i < count; i++)
{
IExpression prefix1 = prefixes1[i];
IExpression prefix2 = prefixes2[i];
if (prefix1 is IArrayIndexerExpression iaie1)
{
if (prefix2 is IArrayIndexerExpression iaie2)
{
if (iaie1.Indices.Count != iaie2.Indices.Count)
{
throw new Exception("Array rank mismatch: " + eb1 + "," + eb2);
}
IList <IExpression> indices = Builder.ExprCollection();
for (int ind = 0; ind < iaie1.Indices.Count; ind++)
{
IExpression index1 = iaie1.Indices[ind];
IExpression index2 = iaie2.Indices[ind];
IExpression index = Unify(index1, eb1.Bindings, index2, eb2.Bindings);
indices.Add(index);
}
parent = Builder.ArrayIndex(parent, indices);
}
else
{
break;
}
}
else
{
throw new Exception("Unhandled expression type: " + prefix1);
}
}
ExpressionWithBindings result = new ExpressionWithBindings();
result.Expression = parent;
if (eb1.Bindings.Count > 0 && eb2.Bindings.Count > 0)
{
result.Bindings.AddRange(eb1.Bindings);
result.Bindings.AddRange(eb2.Bindings);
}
return(result);
// Returns an expression equal to expr1 and expr2 under their respective bindings, or null if the expressions are not equal.
IExpression Unify(
IExpression expr1,
IEnumerable <IReadOnlyCollection <ConditionBinding> > bindings1,
IExpression expr2,
IEnumerable <IReadOnlyCollection <ConditionBinding> > bindings2)
{
if (expr1.Equals(expr2))
{
return(expr1);
}
foreach (IReadOnlyCollection <ConditionBinding> binding2 in bindings2)
{
IExpression expr1b = ReplaceExpression(binding2, expr1);
if (expr1b.Equals(expr2))
{
return(expr1);
}
}
foreach (IReadOnlyCollection <ConditionBinding> binding1 in bindings1)
{
IExpression expr2b = ReplaceExpression(binding1, expr2);
if (expr2b.Equals(expr1))
{
return(expr2);
}
}
bool lift = false;
if (lift)
{
IExpression lifted1 = GetLiftedExpression(expr1, bindings1);
IExpression lifted2 = GetLiftedExpression(expr2, bindings2);
if (lifted1 != null && lifted1.Equals(lifted2))
{
return(lifted1);
}
}
return(Builder.StaticMethod(new Func <int>(GateAnalysisTransform.AnyIndex)));
IExpression GetLiftedExpression(IExpression expr, IEnumerable <IReadOnlyCollection <ConditionBinding> > bindings)
{
IExpression lifted = null;
foreach (IReadOnlyCollection <ConditionBinding> binding in bindings)
{
IExpression lhs = null;
foreach (ConditionBinding b in binding)
{
if (b.rhs.Equals(expr))
{
lhs = b.lhs;
}
}
if (lifted == null)
{
lifted = lhs;
}
else if (lhs == null || !lifted.Equals(lhs))
{
return(null);
}
}
return(lifted);
}
}
}
/// <summary>
/// Add expr to currentBlock.variablesDefined or currentBlock.variablesUsed
/// </summary>
/// <param name="expr"></param>
/// <param name="isDef"></param>
/// <param name="conditionContext"></param>
protected void ProcessUse(IExpression expr, bool isDef, List <ConditionBinding> conditionContext)
{
IVariableDeclaration ivd = Recognizer.GetVariableDeclaration(expr);
if (ivd == null)
{
return;
}
if (!CodeRecognizer.IsStochastic(context, ivd))
{
return;
}
if (gateBlockContext.Count == 0)
{
return;
}
GateBlock currentBlock = gateBlockContext[gateBlockContext.Count - 1];
GateBlock gateBlockOfVar = context.InputAttributes.Get <GateBlock>(ivd);
if (gateBlockOfVar == currentBlock)
{
return; // local variable of the gateBlock
}
ExpressionWithBindings eb = new ExpressionWithBindings(ReplaceLocalIndices(currentBlock, expr), FilterConditionContext(currentBlock));
if (isDef)
{
if (currentBlock.variablesDefined.TryGetValue(ivd, out ExpressionWithBindings eb2))
{
// all definitions of the same variable must have a common parent
currentBlock.variablesDefined[ivd] = GetCommonParent(eb, eb2);
}
else
{
currentBlock.variablesDefined[ivd] = eb;
}
}
else
{
if (currentBlock.variablesUsed.TryGetValue(ivd, out List <ExpressionWithBindings> ebs))
{
// collect all uses that overlap with eb, and replace with their common parent
List <ExpressionWithBindings> notOverlapping = new List <ExpressionWithBindings>();
while (true)
{
foreach (ExpressionWithBindings eb2 in ebs)
{
if (CouldOverlap(eb, eb2, ignoreBindings: GateTransform.DeterministicEnterExit))
{
eb = GetCommonParent(eb, eb2);
}
else
{
notOverlapping.Add(eb2);
}
}
if (notOverlapping.Count == ebs.Count)
{
break; // nothing overlaps
}
// eb must have changed, so try again using the new eb
ebs.Clear();
ebs.AddRange(notOverlapping);
notOverlapping.Clear();
}
ebs.Add(eb);
currentBlock.variablesUsed[ivd] = ebs;
}
else
{
currentBlock.variablesUsed[ivd] = new List <ExpressionWithBindings> {
eb
};
}
}
List <ConditionBinding> FilterConditionContext(GateBlock gateBlock)
{
return(conditionContext
.Where(binding => !CodeRecognizer.IsStochastic(context, binding.lhs) &&
!ContainsLocalVars(gateBlock, binding.lhs) &&
!ContainsLocalVars(gateBlock, binding.rhs))
.ToList());
}
}
