[llvm] [NFC][RootSignature] Use `llvm::EnumEntry` for serialization of Root Signature Elements (PR #144106)

[via llvm-commits]

================
@@ -15,119 +15,117 @@
 #include "llvm/ADT/bit.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Metadata.h"
+#include "llvm/Support/ScopedPrinter.h"
 
 namespace llvm {
 namespace hlsl {
 namespace rootsig {
 
-static raw_ostream &operator<<(raw_ostream &OS, const Register &Reg) {
-  switch (Reg.ViewType) {
-  case RegisterType::BReg:
-    OS << "b";
-    break;
-  case RegisterType::TReg:
-    OS << "t";
-    break;
-  case RegisterType::UReg:
-    OS << "u";
-    break;
-  case RegisterType::SReg:
-    OS << "s";
-    break;
-  }
-  OS << Reg.Number;
-  return OS;
+template <typename T>
+static StringRef getEnumName(const T Value, ArrayRef<EnumEntry<T>> Enums) {
+  for (const auto &EnumItem : Enums)
+    if (EnumItem.Value == Value)
+      return EnumItem.Name;
+  return "";
 }
 
-static raw_ostream &operator<<(raw_ostream &OS,
-                               const ShaderVisibility &Visibility) {
-  switch (Visibility) {
-  case ShaderVisibility::All:
-    OS << "All";
-    break;
-  case ShaderVisibility::Vertex:
-    OS << "Vertex";
-    break;
-  case ShaderVisibility::Hull:
-    OS << "Hull";
-    break;
-  case ShaderVisibility::Domain:
-    OS << "Domain";
-    break;
-  case ShaderVisibility::Geometry:
-    OS << "Geometry";
-    break;
-  case ShaderVisibility::Pixel:
-    OS << "Pixel";
-    break;
-  case ShaderVisibility::Amplification:
-    OS << "Amplification";
-    break;
-  case ShaderVisibility::Mesh:
-    OS << "Mesh";
-    break;
-  }
-
-  return OS;
-}
-
-static raw_ostream &operator<<(raw_ostream &OS, const ClauseType &Type) {
-  switch (Type) {
-  case ClauseType::CBuffer:
-    OS << "CBV";
-    break;
-  case ClauseType::SRV:
-    OS << "SRV";
-    break;
-  case ClauseType::UAV:
-    OS << "UAV";
-    break;
-  case ClauseType::Sampler:
-    OS << "Sampler";
-    break;
-  }
+template <typename T>
+static raw_ostream &printEnum(raw_ostream &OS, const T Value,
+                              ArrayRef<EnumEntry<T>> Enums) {
+  OS << getEnumName(Value, Enums);
 
   return OS;
 }
 
-static raw_ostream &operator<<(raw_ostream &OS,
-                               const DescriptorRangeFlags &Flags) {
+template <typename T>
+static raw_ostream &printFlags(raw_ostream &OS, const T Value,
+                               ArrayRef<EnumEntry<T>> Flags) {
   bool FlagSet = false;
-  unsigned Remaining = llvm::to_underlying(Flags);
+  unsigned Remaining = llvm::to_underlying(Value);
   while (Remaining) {
     unsigned Bit = 1u << llvm::countr_zero(Remaining);
     if (Remaining & Bit) {
       if (FlagSet)
         OS << " | ";
 
-      switch (static_cast<DescriptorRangeFlags>(Bit)) {
-      case DescriptorRangeFlags::DescriptorsVolatile:
-        OS << "DescriptorsVolatile";
-        break;
-      case DescriptorRangeFlags::DataVolatile:
-        OS << "DataVolatile";
-        break;
-      case DescriptorRangeFlags::DataStaticWhileSetAtExecute:
-        OS << "DataStaticWhileSetAtExecute";
-        break;
-      case DescriptorRangeFlags::DataStatic:
-        OS << "DataStatic";
-        break;
-      case DescriptorRangeFlags::DescriptorsStaticKeepingBufferBoundsChecks:
-        OS << "DescriptorsStaticKeepingBufferBoundsChecks";
-        break;
-      default:
+      bool Found = false;
+      for (const auto &FlagItem : Flags)
+        if (FlagItem.Value == T(Bit)) {
+          OS << FlagItem.Name;
+          Found = true;
+          break;
+        }
----------------
joaosaffran wrote:

Isn't that the same as:

```cpp
OS << getEnumName(T(Bit), Flags);
```
?

https://github.com/llvm/llvm-project/pull/144106