Statement TransformForeachOnArray(ForStatement forStatement)
{
if (!context.Settings.ForEachStatement)
{
return(null);
}
Match m = forOnArrayPattern.Match(forStatement);
if (!m.Success)
{
return(null);
}
var itemVariable = m.Get <IdentifierExpression>("itemVariable").Single().GetILVariable();
var indexVariable = m.Get <IdentifierExpression>("indexVariable").Single().GetILVariable();
var arrayVariable = m.Get <IdentifierExpression>("arrayVariable").Single().GetILVariable();
var loopContainer = forStatement.Annotation <IL.BlockContainer>();
if (itemVariable == null || indexVariable == null || arrayVariable == null)
{
return(null);
}
if (!itemVariable.IsSingleDefinition || (itemVariable.CaptureScope != null && itemVariable.CaptureScope != loopContainer))
{
return(null);
}
if (indexVariable.StoreCount != 2 || indexVariable.LoadCount != 3 || indexVariable.AddressCount != 0)
{
return(null);
}
var body = new BlockStatement();
foreach (var statement in m.Get <Statement>("statements"))
{
body.Statements.Add(statement.Detach());
}
var foreachStmt = new ForeachStatement {
VariableType = context.Settings.AnonymousTypes && itemVariable.Type.ContainsAnonymousType() ? new SimpleType("var") : context.TypeSystemAstBuilder.ConvertType(itemVariable.Type),
VariableName = itemVariable.Name,
InExpression = m.Get <IdentifierExpression>("arrayVariable").Single().Detach(),
EmbeddedStatement = body
};
foreachStmt.CopyAnnotationsFrom(forStatement);
itemVariable.Kind = IL.VariableKind.ForeachLocal;
// Add the variable annotation for highlighting (TokenTextWriter expects it directly on the ForeachStatement).
foreachStmt.AddAnnotation(new ILVariableResolveResult(itemVariable, itemVariable.Type));
// TODO : add ForeachAnnotation
forStatement.ReplaceWith(foreachStmt);
return(foreachStmt);
}
public static ForeachStatement WithILVariable(this ForeachStatement loop, ILVariable v)
{
loop.AddAnnotation(v);
return(loop);
}
Statement TransformToForeach(UsingInstruction inst, out Expression resource)
{
// Check if the using resource matches the GetEnumerator pattern.
resource = exprBuilder.Translate(inst.ResourceExpression);
var m = getEnumeratorPattern.Match(resource);
// The using body must be a BlockContainer.
if (!(inst.Body is BlockContainer container) || !m.Success)
{
return(null);
}
// The using-variable is the enumerator.
var enumeratorVar = inst.Variable;
// If there's another BlockContainer nested in this container and it only has one child block, unwrap it.
// If there's an extra leave inside the block, extract it into optionalReturnAfterLoop.
var loopContainer = UnwrapNestedContainerIfPossible(container, out var optionalReturnAfterLoop);
// Detect whether we're dealing with a while loop with multiple embedded statements.
var loop = DetectedLoop.DetectLoop(loopContainer);
if (loop.Kind != LoopKind.While || !(loop.Body is Block body))
{
return(null);
}
// The loop condition must be a call to enumerator.MoveNext()
var condition = exprBuilder.TranslateCondition(loop.Conditions.Single());
var m2 = moveNextConditionPattern.Match(condition.Expression);
if (!m2.Success)
{
return(null);
}
// Check enumerator variable references.
var enumeratorVar2 = m2.Get <IdentifierExpression>("enumerator").Single().GetILVariable();
if (enumeratorVar2 != enumeratorVar)
{
return(null);
}
// Detect which foreach-variable transformation is necessary/possible.
var transformation = DetectGetCurrentTransformation(container, body, enumeratorVar, condition.ILInstructions.Single(),
out var singleGetter, out var foreachVariable);
if (transformation == RequiredGetCurrentTransformation.NoForeach)
{
return(null);
}
// The existing foreach variable, if found, can only be used in the loop container.
if (foreachVariable != null && !(foreachVariable.CaptureScope == null || foreachVariable.CaptureScope == loopContainer))
{
return(null);
}
// Extract in-expression
var collectionExpr = m.Get <Expression>("collection").Single();
// Special case: foreach (var item in this) is decompiled as foreach (var item in base)
// but a base reference is not valid in this context.
if (collectionExpr is BaseReferenceExpression)
{
collectionExpr = new ThisReferenceExpression().CopyAnnotationsFrom(collectionExpr);
}
// Handle explicit casts:
// This is the case if an explicit type different from the collection-item-type was used.
// For example: foreach (ClassA item in nonGenericEnumerable)
var type = singleGetter.Method.ReturnType;
ILInstruction instToReplace = singleGetter;
switch (instToReplace.Parent)
{
case CastClass cc:
type = cc.Type;
instToReplace = cc;
break;
case UnboxAny ua:
type = ua.Type;
instToReplace = ua;
break;
}
// Handle the required foreach-variable transformation:
switch (transformation)
{
case RequiredGetCurrentTransformation.UseExistingVariable:
foreachVariable.Type = type;
foreachVariable.Kind = VariableKind.ForeachLocal;
foreachVariable.Name = AssignVariableNames.GenerateForeachVariableName(currentFunction, collectionExpr.Annotation <ILInstruction>(), foreachVariable);
break;
case RequiredGetCurrentTransformation.UninlineAndUseExistingVariable:
// Unwrap stloc chain.
var nestedStores = new Stack <ILVariable>();
var currentInst = instToReplace; // instToReplace is the innermost value of the stloc chain.
while (currentInst.Parent is StLoc stloc)
{
// Exclude nested stores to foreachVariable
// we'll insert one store at the beginning of the block.
if (stloc.Variable != foreachVariable && stloc.Parent is StLoc)
{
nestedStores.Push(stloc.Variable);
}
currentInst = stloc;
}
// Rebuild the nested store instructions:
ILInstruction reorderedStores = new LdLoc(foreachVariable);
while (nestedStores.Count > 0)
{
reorderedStores = new StLoc(nestedStores.Pop(), reorderedStores);
}
currentInst.ReplaceWith(reorderedStores);
body.Instructions.Insert(0, new StLoc(foreachVariable, instToReplace));
// Adjust variable type, kind and name.
goto case RequiredGetCurrentTransformation.UseExistingVariable;
case RequiredGetCurrentTransformation.IntroduceNewVariable:
foreachVariable = currentFunction.RegisterVariable(
VariableKind.ForeachLocal, type,
AssignVariableNames.GenerateForeachVariableName(currentFunction, collectionExpr.Annotation <ILInstruction>())
);
instToReplace.ReplaceWith(new LdLoc(foreachVariable));
body.Instructions.Insert(0, new StLoc(foreachVariable, instToReplace));
break;
}
// Convert the modified body to C# AST:
var whileLoop = (WhileStatement)ConvertAsBlock(container).First();
BlockStatement foreachBody = (BlockStatement)whileLoop.EmbeddedStatement.Detach();
// Remove the first statement, as it is the foreachVariable = enumerator.Current; statement.
foreachBody.Statements.First().Detach();
// Construct the foreach loop.
var foreachStmt = new ForeachStatement {
VariableType = settings.AnonymousTypes && foreachVariable.Type.ContainsAnonymousType() ? new SimpleType("var") : exprBuilder.ConvertType(foreachVariable.Type),
VariableName = foreachVariable.Name,
InExpression = collectionExpr.Detach(),
EmbeddedStatement = foreachBody
};
// Add the variable annotation for highlighting (TokenTextWriter expects it directly on the ForeachStatement).
foreachStmt.AddAnnotation(new ILVariableResolveResult(foreachVariable, foreachVariable.Type));
// If there was an optional return statement, return it as well.
if (optionalReturnAfterLoop != null)
{
return(new BlockStatement {
Statements =
{
foreachStmt,
optionalReturnAfterLoop.AcceptVisitor(this)
}
});
}
return(foreachStmt);
}
/// <summary>
/// Adds an <see cref="ILVariable"/> to this foreach statement.
/// </summary>
public static ForeachStatement WithILVariable(this ForeachStatement loop, ILVariable v)
{
loop.AddAnnotation(new ILVariableResolveResult(v, v.Type));
return(loop);
}
Statement TransformForeachOnMultiDimArray(ExpressionStatement expressionStatement)
{
if (!context.Settings.ForEachStatement)
{
return(null);
}
Match m;
Statement stmt = expressionStatement;
IL.ILVariable collection = null;
IL.ILVariable[] upperBounds = null;
List <Statement> statementsToDelete = new List <Statement>();
int i = 0;
// first we look for all the upper bound initializations
do
{
m = variableAssignUpperBoundPattern.Match(stmt);
if (!m.Success)
{
break;
}
if (upperBounds == null)
{
collection = m.Get <IdentifierExpression>("collection").Single().GetILVariable();
if (!(collection?.Type is Decompiler.TypeSystem.ArrayType arrayType))
{
break;
}
upperBounds = new IL.ILVariable[arrayType.Dimensions];
}
else
{
statementsToDelete.Add(stmt);
}
var nextCollection = m.Get <IdentifierExpression>("collection").Single().GetILVariable();
if (nextCollection != collection)
{
break;
}
if (!int.TryParse(m.Get <PrimitiveExpression>("index").Single().Value?.ToString() ?? "", out int index) || index != i)
{
break;
}
upperBounds[i] = m.Get <IdentifierExpression>("variable").Single().GetILVariable();
stmt = stmt.GetNextStatement();
i++;
} while (stmt != null && i < upperBounds.Length);
if (upperBounds?.LastOrDefault() == null || collection == null)
{
return(null);
}
if (!MatchForeachOnMultiDimArray(upperBounds, collection, stmt, out var foreachVariable, out var statements, out var lowerBounds))
{
return(null);
}
statementsToDelete.Add(stmt);
statementsToDelete.Add(stmt.GetNextStatement());
var itemVariable = foreachVariable.GetILVariable();
if (itemVariable == null || !itemVariable.IsSingleDefinition ||
!upperBounds.All(ub => ub.IsSingleDefinition && ub.LoadCount == 1) ||
!lowerBounds.All(lb => lb.StoreCount == 2 && lb.LoadCount == 3 && lb.AddressCount == 0))
{
return(null);
}
var body = new BlockStatement();
foreach (var statement in statements)
{
body.Statements.Add(statement.Detach());
}
var foreachStmt = new ForeachStatement {
VariableType = context.Settings.AnonymousTypes && itemVariable.Type.ContainsAnonymousType() ? new SimpleType("var") : context.TypeSystemAstBuilder.ConvertType(itemVariable.Type),
VariableName = itemVariable.Name,
InExpression = m.Get <IdentifierExpression>("collection").Single().Detach(),
EmbeddedStatement = body
};
foreach (var statement in statementsToDelete)
{
statement.Detach();
}
//foreachStmt.CopyAnnotationsFrom(forStatement);
itemVariable.Kind = IL.VariableKind.ForeachLocal;
// Add the variable annotation for highlighting (TokenTextWriter expects it directly on the ForeachStatement).
foreachStmt.AddAnnotation(new ILVariableResolveResult(itemVariable, itemVariable.Type));
// TODO : add ForeachAnnotation
expressionStatement.ReplaceWith(foreachStmt);
return(foreachStmt);
}
Statement TransformToForeach(UsingInstruction inst, out Expression resource)
{
resource = exprBuilder.Translate(inst.ResourceExpression);
var m = getEnumeratorPattern.Match(resource);
if (!(inst.Body is BlockContainer container) || !m.Success)
{
return(null);
}
var enumeratorVar = inst.Variable;
var loopContainer = UnwrapNestedContainerIfPossible(container, out var optionalReturnAfterLoop);
var loop = DetectedLoop.DetectLoop(loopContainer);
if (loop.Kind != LoopKind.While || !(loop.Body is Block body))
{
return(null);
}
var condition = exprBuilder.TranslateCondition(loop.Conditions.Single());
var m2 = moveNextConditionPattern.Match(condition.Expression);
if (!m2.Success)
{
return(null);
}
var enumeratorVar2 = m2.Get <IdentifierExpression>("enumerator").Single().GetILVariable();
if (enumeratorVar2 != enumeratorVar || !BodyHasSingleGetCurrent(body, enumeratorVar, condition.ILInstructions.Single(),
out var singleGetter, out var needsUninlining, out var itemVariable))
{
return(null);
}
if (itemVariable != null && !(itemVariable.CaptureScope == null || itemVariable.CaptureScope == loopContainer))
{
return(null);
}
var collectionExpr = m.Get <Expression>("collection").Single();
if (collectionExpr is BaseReferenceExpression)
{
collectionExpr = new ThisReferenceExpression().CopyAnnotationsFrom(collectionExpr);
}
var type = singleGetter.Method.ReturnType;
ILInstruction instToReplace = singleGetter;
switch (instToReplace.Parent)
{
case CastClass cc:
type = cc.Type;
instToReplace = cc;
break;
case UnboxAny ua:
type = ua.Type;
instToReplace = ua;
break;
}
if (needsUninlining)
{
itemVariable = currentFunction.RegisterVariable(
VariableKind.ForeachLocal, type,
AssignVariableNames.GenerateForeachVariableName(currentFunction, collectionExpr.Annotation <ILInstruction>())
);
instToReplace.ReplaceWith(new LdLoc(itemVariable));
body.Instructions.Insert(0, new StLoc(itemVariable, instToReplace));
}
else
{
if (itemVariable.StoreCount != 1)
{
return(null);
}
itemVariable.Type = type;
itemVariable.Kind = VariableKind.ForeachLocal;
itemVariable.Name = AssignVariableNames.GenerateForeachVariableName(currentFunction, collectionExpr.Annotation <ILInstruction>(), itemVariable);
}
var whileLoop = (WhileStatement)ConvertAsBlock(container).First();
BlockStatement foreachBody = (BlockStatement)whileLoop.EmbeddedStatement.Detach();
foreachBody.Statements.First().Detach();
var foreachStmt = new ForeachStatement {
VariableType = settings.AnonymousTypes && itemVariable.Type.ContainsAnonymousType() ? new SimpleType("var") : exprBuilder.ConvertType(itemVariable.Type),
VariableName = itemVariable.Name,
InExpression = collectionExpr.Detach(),
EmbeddedStatement = foreachBody
};
foreachStmt.AddAnnotation(new ILVariableResolveResult(itemVariable, itemVariable.Type));
if (optionalReturnAfterLoop != null)
{
return(new BlockStatement {
Statements =
{
foreachStmt,
optionalReturnAfterLoop.AcceptVisitor(this)
}
});
}
return(foreachStmt);
}
