public override BoundNode VisitStackAllocArrayCreation(BoundStackAllocArrayCreation node)
{
BoundExpression rewrittenCount = VisitExpression(node.Count);
// From ILGENREC::genExpr:
// EDMAURER always perform a checked multiply regardless of the context.
// localloc takes an unsigned native int. When a user specifies a negative
// count of elements, per spec, the behavior is undefined. So convert element
// count to unsigned.
// NOTE: to match this special case logic, we're going to construct the multiplication
// ourselves, rather than calling MakeSizeOfMultiplication (which inserts various checks
// and conversions).
TypeSymbol uintType = _factory.SpecialType(SpecialType.System_UInt32);
TypeSymbol uintPtrType = _factory.SpecialType(SpecialType.System_UIntPtr);
// Why convert twice? Because dev10 actually uses an explicit conv_u instruction and the normal conversion
// from int32 to native uint is emitted as conv_i. The behavior we want to emulate is to re-interpret
// (i.e. unchecked) an int32 as unsigned (i.e. uint32) and then convert it to a native uint *without* sign
// extension.
BoundExpression convertedCount = _factory.Convert(uintType, rewrittenCount, Conversion.ExplicitNumeric);
convertedCount = _factory.Convert(uintPtrType, convertedCount, Conversion.IntegerToPointer);
BoundExpression sizeOfExpression = _factory.Sizeof(((PointerTypeSymbol)node.Type).PointedAtType);
BinaryOperatorKind multiplicationKind = BinaryOperatorKind.Checked | BinaryOperatorKind.UIntMultiplication; //"UInt" just to make it unsigned
BoundExpression product = _factory.Binary(multiplicationKind, uintPtrType, convertedCount, sizeOfExpression);
return node.Update(product, node.Type);
}
internal void Parse(BoundStackAllocArrayCreation boundStackAllocArrayCreation)
{
base.Parse(boundStackAllocArrayCreation);
this.Count = Deserialize(boundStackAllocArrayCreation.Count) as Expression;
}
private void EmitStackAllocArrayCreationExpression(BoundStackAllocArrayCreation expression, bool used)
{
EmitExpression(expression.Count, used: true);
_builder.EmitOpCode(ILOpCode.Localloc);
EmitPopIfUnused(used); //localalloc could overflow the stack, so don't omit, even if used.
}
public override BoundNode VisitStackAllocArrayCreation(BoundStackAllocArrayCreation node)
{
// CLI spec section 3.47 requires that the stack be empty when localloc occurs.
EnsureOnlyEvalStack();
return base.VisitStackAllocArrayCreation(node);
}
