/// <summary>
/// While computing layout, we don't generally compute the full field information. This function is used to
/// gate how much of field layout to run
/// </summary>
/// <param name="fieldStorage">the conceptual location of the field</param>
/// <param name="loadRequested">what sort of load was requested</param>
/// <returns></returns>
internal bool ShouldProcessField(NativeFormat.FieldStorage fieldStorage, FieldLoadState loadRequested)
{
if (fieldStorage == (int)NativeFormat.FieldStorage.Instance)
{
// Make sure we wanted to load instance fields.
if ((loadRequested & FieldLoadState.Instance) == FieldLoadState.None)
{
return(false);
}
}
else if ((loadRequested & FieldLoadState.Statics) == FieldLoadState.None)
{
// Otherwise the field is a static, and we only want instance fields.
return(false);
}
return(true);
}
// The layout algorithm should probably compute results and let the caller set things
internal unsafe LayoutInt[] ComputeTypeSizeAndAlignment(TypeDesc type, FieldLoadState loadRequested, out LowLevelList <LayoutInt> fieldOffsets)
{
fieldOffsets = null;
TypeLoaderLogger.WriteLine("Laying out type " + type.ToString() + ". IsValueType: " + (type.IsValueType ? "true" : "false") + ". LoadRequested = " + ((int)loadRequested).LowLevelToString());
Debug.Assert(loadRequested != FieldLoadState.None);
Debug.Assert(type is ArrayType || (type is DefType && ((DefType)type).HasInstantiation));
bool isArray = type is ArrayType;
LayoutInt[] position = new LayoutInt[5];
LayoutInt alignRequired = LayoutInt.One;
if ((loadRequested & FieldLoadState.Instance) == FieldLoadState.Instance)
{
ComputeTypeSizeBeforeFields(type, out position[(int)NativeFormat.FieldStorage.Instance], out alignRequired);
}
if (!isArray)
{
// Once this is done, the NativeLayoutFields on the type are initialized
EnsureFieldLayoutLoadedForGenericType((DefType)type);
Debug.Assert(type.NativeLayoutFields != null);
}
int instanceFields = 0;
if (!isArray && type.NativeLayoutFields.Length > 0)
{
fieldOffsets = new LowLevelList <LayoutInt>(type.NativeLayoutFields.Length);
for (int i = 0; i < type.NativeLayoutFields.Length; i++)
{
TypeDesc fieldType = type.NativeLayoutFields[i].FieldType;
int fieldStorage = (int)type.NativeLayoutFields[i].FieldStorage;
if (!ShouldProcessField((NativeFormat.FieldStorage)fieldStorage, loadRequested))
{
continue;
}
// For value types, we will attempt to get the size and alignment from
// the runtime if possible, otherwise GetFieldSizeAndAlignment will
// recurse to lay out nested struct fields.
LayoutInt alignment;
LayoutInt size;
GetFieldSizeAlignment(fieldType, out size, out alignment);
Debug.Assert(alignment.AsInt > 0);
if (fieldStorage == (int)NativeFormat.FieldStorage.Instance)
{
instanceFields++;
// Ensure alignment of type is sufficient for this field
alignRequired = LayoutInt.Max(alignRequired, alignment);
}
position[fieldStorage] = LayoutInt.AlignUp(position[fieldStorage], alignment);
TypeLoaderLogger.WriteLine(" --> Field type " + fieldType.ToString() +
" storage " + ((uint)(type.NativeLayoutFields[i].FieldStorage)).LowLevelToString() +
" offset " + position[fieldStorage].LowLevelToString() +
" alignment " + alignment.LowLevelToString());
fieldOffsets.Add(position[fieldStorage]);
position[fieldStorage] += size;
}
}
// Pad the length of structs to be 1 if they are empty so we have no zero-length structures
if ((position[(int)NativeFormat.FieldStorage.Instance] == LayoutInt.Zero) && type.IsValueType)
{
position[(int)NativeFormat.FieldStorage.Instance] = LayoutInt.One;
}
Debug.Assert(alignRequired == new LayoutInt(1) ||
alignRequired == new LayoutInt(2) ||
alignRequired == new LayoutInt(4) ||
alignRequired == new LayoutInt(8));
position[InstanceAlignmentEntry] = alignRequired;
return(position);
}
// The layout algorithm should probably compute results and let the caller set things
internal unsafe int[] ComputeTypeSizeAndAlignment(TypeDesc type, FieldLoadState loadRequested, out LowLevelList<int> fieldOffsets)
{
fieldOffsets = null;
TypeLoaderLogger.WriteLine("Laying out type " + type.ToString() + ". IsValueType: " + (type.IsValueType ? "true" : "false") + ". LoadRequested = " + ((int)loadRequested).LowLevelToString());
Debug.Assert(loadRequested != FieldLoadState.None);
Debug.Assert(type is ArrayType || (type is DefType && ((DefType)type).HasInstantiation));
bool isArray = type is ArrayType;
int[] position = new int[5];
int alignRequired = 1;
if ((loadRequested & FieldLoadState.Instance) == FieldLoadState.Instance)
{
ComputeTypeSizeBeforeFields(type, out position[(int)NativeFormat.FieldStorage.Instance], out alignRequired);
}
if (!isArray)
{
// Once this is done, the NativeLayoutFields on the type are initialized
EnsureFieldLayoutLoadedForGenericType((DefType)type);
Debug.Assert(type.NativeLayoutFields != null);
}
int instanceFields = 0;
if (!isArray && type.NativeLayoutFields.Length > 0)
{
fieldOffsets = new LowLevelList<int>(type.NativeLayoutFields.Length);
for (int i = 0; i < type.NativeLayoutFields.Length; i++)
{
TypeDesc fieldType = type.NativeLayoutFields[i].FieldType;
int fieldStorage = (int)type.NativeLayoutFields[i].FieldStorage;
if (!ShouldProcessField((NativeFormat.FieldStorage)fieldStorage, loadRequested))
continue;
// For value types, we will attempt to get the size and alignment from
// the runtime if possible, otherwise GetFieldSizeAndAlignment will
// recurse to lay out nested struct fields.
int alignment;
int size;
GetFieldSizeAlignment(fieldType, out size, out alignment);
Debug.Assert(alignment > 0);
if (fieldStorage == (int)NativeFormat.FieldStorage.Instance)
{
instanceFields++;
// Ensure alignment of type is sufficient for this field
if (alignRequired < alignment)
alignRequired = alignment;
}
position[fieldStorage] = MemoryHelpers.AlignUp(position[fieldStorage], alignment);
TypeLoaderLogger.WriteLine(" --> Field type " + fieldType.ToString() +
" storage " + ((uint)(type.NativeLayoutFields[i].FieldStorage)).LowLevelToString() +
" offset " + position[fieldStorage].LowLevelToString() +
" alignment " + alignment.LowLevelToString());
fieldOffsets.Add(position[fieldStorage]);
position[fieldStorage] += size;
}
}
// Pad the length of structs to be 1 if they are empty so we have no zero-length structures
if ((position[(int)NativeFormat.FieldStorage.Instance] == 0) && type.IsValueType)
position[(int)NativeFormat.FieldStorage.Instance] = 1;
Debug.Assert(alignRequired == 1 || alignRequired == 2 || alignRequired == 4 || alignRequired == 8);
position[InstanceAlignmentEntry] = alignRequired;
return position;
}
/// <summary>
/// While computing layout, we don't generally compute the full field information. This function is used to
/// gate how much of field layout to run
/// </summary>
/// <param name="fieldStorage">the conceptual location of the field</param>
/// <param name="loadRequested">what sort of load was requested</param>
/// <returns></returns>
internal bool ShouldProcessField(NativeFormat.FieldStorage fieldStorage, FieldLoadState loadRequested)
{
if (fieldStorage == (int)NativeFormat.FieldStorage.Instance)
{
// Make sure we wanted to load instance fields.
if ((loadRequested & FieldLoadState.Instance) == FieldLoadState.None)
return false;
}
else if ((loadRequested & FieldLoadState.Statics) == FieldLoadState.None)
{
// Otherwise the field is a static, and we only want instance fields.
return false;
}
return true;
}
