[clang] [HLSL] Collect explicit resource binding information (PR #111203)

[Damyan Pepper via cfe-commits]

================
@@ -58,31 +56,82 @@ static RegisterType getRegisterType(ResourceClass RC) {
   llvm_unreachable("unexpected ResourceClass value");
 }
 
-static RegisterType getRegisterType(StringRef Slot) {
+// Converts the first letter of string Slot to RegisterType.
+// Returns false if the letter does not correspond to a valid register type.
+static bool convertToRegisterType(StringRef Slot, RegisterType *RT) {
----------------
damyanp wrote:

Probably not worth the effort...but maybe this is the sort of pattern we could be using for this?

```suggestion
static Expected<RegisterType> convertToRegisterType(StringRef Slot {
```

https://github.com/llvm/llvm-project/pull/111203