/// <summary>
/// Emits instructions to conform a required access type.
/// </summary>
/// <param name="callExpression">Expression emitting the call.</param>
/// <param name="loadAddress">Whether to load an address of the return value.</param>
/// <param name="result">The type code of a top item of the evaluation stack.</param>
public void EmitReturnValueHandling(Expression/*!*/ callExpression, bool loadAddress, ref PhpTypeCode result)
{
Debug.Assert(callExpression != null);
if (loadAddress)
{
if (result == PhpTypeCode.PhpReference)
{
// LOADADDR STACK.Value;
il.Emit(OpCodes.Ldflda, Fields.PhpReference_Value);
}
else
{
if (result == PhpTypeCode.Void)
il.Emit(OpCodes.Ldnull);
// local = STACK;
// LOADADDR local;
LocalBuilder local = il.GetTemporaryLocal(PhpTypeCodeEnum.ToType(result), true);
il.Stloc(local);
il.Ldloca(local);
}
result = PhpTypeCode.ObjectAddress;
return;
}
switch (callExpression.GetAccess())
{
case AccessType.None:
// return value is discarded:
if (result != PhpTypeCode.Void)
{
il.Emit(OpCodes.Pop);
result = PhpTypeCode.Void;
}
break;
case AccessType.ReadUnknown:
case AccessType.ReadRef:
if (result != PhpTypeCode.PhpReference)
{
// return value is "boxed" to PhpReference:
if (result != PhpTypeCode.Void)
{
EmitBoxing(result);
EmitVariableCopy(CopyReason.ReturnedByCopy, callExpression);
il.Emit(OpCodes.Newobj, Constructors.PhpReference_Object);
}
else
{
il.Emit(OpCodes.Newobj, Constructors.PhpReference_Void);
}
result = PhpTypeCode.PhpReference;
}
break;
case AccessType.Read:
if (result == PhpTypeCode.PhpReference)
{
// return value is dereferenced:
il.Emit(OpCodes.Ldfld, Fields.PhpReference_Value);
result = PhpTypeCode.Object;
}
else if (result == PhpTypeCode.Void)
{
// null value is loaded as a result:
il.Emit(OpCodes.Ldnull);
result = PhpTypeCode.Object;
}
break;
default:
Debug.Fail(null);
break;
}
}
