public override FieldLayoutAlgorithm GetLayoutAlgorithmForType(DefType type)
{
if (type == UniversalCanonType)
{
return(UniversalCanonLayoutAlgorithm.Instance);
}
else if (VectorFieldLayoutAlgorithm.IsVectorType(type))
{
return(_vectorFieldLayoutAlgorithm);
}
else if (Int128FieldLayoutAlgorithm.IsIntegerType(type))
{
return(_int128FieldLayoutAlgorithm);
}
return(_metadataFieldLayout);
}
public TestTypeSystemContext(TargetArchitecture arch, TargetOS targetOS = TargetOS.Unknown)
: base(new TargetDetails(arch, targetOS, TargetAbi.Unknown))
{
_vectorFieldLayoutAlgorithm = new VectorFieldLayoutAlgorithm(_metadataFieldLayout, true);
_int128FieldLayoutAlgorithm = new Int128FieldLayoutAlgorithm(_metadataFieldLayout);
}
/// <summary>
/// Returns 'true' if the struct is passed in registers, 'false' otherwise.
/// </summary>
private static bool ClassifyEightBytes(TypeDesc typeDesc,
ref SystemVStructRegisterPassingHelper helper,
int startOffsetOfStruct)
{
FieldDesc firstField = null;
int numIntroducedFields = 0;
foreach (FieldDesc field in typeDesc.GetFields())
{
if (!field.IsStatic)
{
if (firstField == null)
{
firstField = field;
}
numIntroducedFields++;
}
}
if (numIntroducedFields == 0)
{
return(false);
}
// The SIMD and Int128 Intrinsic types are meant to be handled specially and should not be passed as struct registers
if (typeDesc.IsIntrinsic)
{
InstantiatedType instantiatedType = typeDesc as InstantiatedType;
if (instantiatedType != null)
{
if (VectorFieldLayoutAlgorithm.IsVectorType(instantiatedType) ||
VectorOfTFieldLayoutAlgorithm.IsVectorOfTType(instantiatedType) ||
Int128FieldLayoutAlgorithm.IsIntegerType(instantiatedType))
{
return(false);
}
}
}
MetadataType mdType = typeDesc as MetadataType;
Debug.Assert(mdType != null);
TypeDesc firstFieldElementType = firstField.FieldType;
int firstFieldSize = firstFieldElementType.GetElementSize().AsInt;
// A fixed buffer type is always a value type that has exactly one value type field at offset 0
// and who's size is an exact multiple of the size of the field.
// It is possible that we catch a false positive with this check, but that chance is extremely slim
// and the user can always change their structure to something more descriptive of what they want
// instead of adding additional padding at the end of a one-field structure.
// We do this check here to save looking up the FixedBufferAttribute when loading the field
// from metadata.
bool isFixedBuffer = numIntroducedFields == 1 &&
firstFieldElementType.IsValueType &&
firstField.Offset.AsInt == 0 &&
mdType.HasLayout() &&
((typeDesc.GetElementSize().AsInt % firstFieldSize) == 0);
if (isFixedBuffer)
{
numIntroducedFields = typeDesc.GetElementSize().AsInt / firstFieldSize;
}
int fieldIndex = 0;
foreach (FieldDesc field in FieldEnumerator.GetInstanceFields(typeDesc, isFixedBuffer, numIntroducedFields))
{
Debug.Assert(fieldIndex < numIntroducedFields);
int fieldOffset = isFixedBuffer ? fieldIndex * firstFieldSize : field.Offset.AsInt;
int normalizedFieldOffset = fieldOffset + startOffsetOfStruct;
int fieldSize = field.FieldType.GetElementSize().AsInt;
// The field can't span past the end of the struct.
if ((normalizedFieldOffset + fieldSize) > helper.StructSize)
{
Debug.Assert(false, "Invalid struct size. The size of fields and overall size don't agree");
return(false);
}
SystemVClassificationType fieldClassificationType;
if (typeDesc.IsByReferenceOfT)
{
// ByReference<T> is a special type whose single IntPtr field holds a by-ref potentially interior pointer to GC
// memory, so classify its field as such
Debug.Assert(numIntroducedFields == 1);
Debug.Assert(field.FieldType.IsWellKnownType(WellKnownType.IntPtr));
fieldClassificationType = SystemVClassificationTypeIntegerByRef;
}
else
{
fieldClassificationType = TypeDef2SystemVClassification(field.FieldType);
}
if (fieldClassificationType == SystemVClassificationTypeStruct)
{
bool inEmbeddedStructPrev = helper.InEmbeddedStruct;
helper.InEmbeddedStruct = true;
bool structRet = false;
structRet = ClassifyEightBytes(field.FieldType, ref helper, normalizedFieldOffset);
helper.InEmbeddedStruct = inEmbeddedStructPrev;
if (!structRet)
{
// If the nested struct says not to enregister, there's no need to continue analyzing at this level. Just return do not enregister.
return(false);
}
continue;
}
if ((normalizedFieldOffset % fieldSize) != 0)
{
// The spec requires that struct values on the stack from register passed fields expects
// those fields to be at their natural alignment.
return(false);
}
if (normalizedFieldOffset <= helper.LargestFieldOffset)
{
// Find the field corresponding to this offset and update the size if needed.
// If the offset matches a previously encountered offset, update the classification and field size.
int i;
for (i = helper.CurrentUniqueOffsetField - 1; i >= 0; i--)
{
if (helper.FieldOffsets[i] == normalizedFieldOffset)
{
if (fieldSize > helper.FieldSizes[i])
{
helper.FieldSizes[i] = fieldSize;
}
helper.FieldClassifications[i] = ReClassifyField(helper.FieldClassifications[i], fieldClassificationType);
break;
}
}
if (i >= 0)
{
// The proper size of the union set of fields has been set above; continue to the next field.
continue;
}
}
else
{
helper.LargestFieldOffset = (int)normalizedFieldOffset;
}
// Set the data for a new field.
// The new field classification must not have been initialized yet.
Debug.Assert(helper.FieldClassifications[helper.CurrentUniqueOffsetField] == SystemVClassificationTypeNoClass);
// There are only a few field classifications that are allowed.
Debug.Assert((fieldClassificationType == SystemVClassificationTypeInteger) ||
(fieldClassificationType == SystemVClassificationTypeIntegerReference) ||
(fieldClassificationType == SystemVClassificationTypeIntegerByRef) ||
(fieldClassificationType == SystemVClassificationTypeSSE));
helper.FieldClassifications[helper.CurrentUniqueOffsetField] = fieldClassificationType;
helper.FieldSizes[helper.CurrentUniqueOffsetField] = fieldSize;
helper.FieldOffsets[helper.CurrentUniqueOffsetField] = normalizedFieldOffset;
Debug.Assert(helper.CurrentUniqueOffsetField < SYSTEMV_MAX_NUM_FIELDS_IN_REGISTER_PASSED_STRUCT);
helper.CurrentUniqueOffsetField++;
fieldIndex++;
}
AssignClassifiedEightByteTypes(ref helper);
return(true);
}
