[llvm] [DirectX] Implement Shader Flag Analysis for `UAVsAtEveryStage` (PR #137085)

[Deric C. via llvm-commits]

================
@@ -32,6 +32,35 @@
 using namespace llvm;
 using namespace llvm::dxil;
 
+static bool hasUAVsAtEveryStage(DXILResourceMap &DRM,
+                                const ModuleMetadataInfo &MMDI) {
+  if (DRM.uavs().empty())
+    return false;
+
+  switch (MMDI.ShaderProfile) {
+  default:
+    return false;
+  case Triple::EnvironmentType::Compute:
+  case Triple::EnvironmentType::Pixel:
+    return false;
+  case Triple::EnvironmentType::Vertex:
+  case Triple::EnvironmentType::Geometry:
+  case Triple::EnvironmentType::Hull:
+  case Triple::EnvironmentType::Domain:
+    return true;
----------------
Icohedron wrote:

@bogner Do you think the `hasUAVsAtEveryStage` function should be this instead?
```c++
bool hasUAVsAtEveryStage(DXILResourceMap &DRM, const ModuleMetadataInfo &MMDI) {
  if (DRM.uavs().empty())
    return false;

  switch (MMDI.ShaderProfile) {
  default:
    return MMDI.ValidatorVersion < VersionTuple(1, 8);
  case Triple::EnvironmentType::Compute:
  case Triple::EnvironmentType::Pixel:
    return false;
  case Triple::EnvironmentType::Vertex:
  case Triple::EnvironmentType::Geometry:
  case Triple::EnvironmentType::Hull:
  case Triple::EnvironmentType::Domain:
    return true;
  }
}
```
This is so that we don't have to edit the switch every time a new shader stage gets added.

https://github.com/llvm/llvm-project/pull/137085