| Issue |
145439
|
| Summary |
[DirectX] Root signature's `DescriptorTableView` has undefined behaviour for version 1.0 root signatures.
|
| Labels |
backend:DirectX
|
| Assignees |
|
| Reporter |
bogner
|
We currently have the "DescriptorTableView" load a `DirectX::DescriptorTable` with a type like so:
```c++
struct DescriptorTable {
uint32_t NumRanges;
uint32_t RangesOffset;
ViewArray<dxbc::RTS0::v2::DescriptorRange> Ranges;
};
```
However, we set up the ranges view like so:
```c++
size_t RangeSize = sizeof(dxbc::RTS0::v1::DescriptorRange);
if (Version > 1)
RangeSize = sizeof(dxbc::RTS0::v2::DescriptorRange);
Table.Ranges.Stride = RangeSize;
Table.Ranges.Data =
"" * sizeof(uint32_t), Table.NumRanges * RangeSize);
```
This invokes undefined behaviour. It is not legal to store a `dxbc::RTS0::v1::DescriptorRange` in an object of type `dxbc::RTS0::v2::DescriptorRange` (the inheritance is in the other direction. Furthermore, `dxbc::RTS0::v2::DescriptorRange` will not fit in `sizeof(dxbc::RTS0::v1::DescriptorRange)`, and the last field (currently `Flags`) will overlap with the next object.
Note: this may become moot depending on the fix to #145438, as that issue implies that we won't be able to have an inheritance relationship between the versions of DescriptorRange at all.
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