[clang] [HLSL] Adjust resource binding diagnostic flags code (PR #106657)

[Helena Kotas via cfe-commits]

================
@@ -612,57 +588,61 @@ static RegisterBindingFlags HLSLFillRegisterBindingFlags(Sema &S,
     return Flags;
   }
 
-  if (!isDeclaredWithinCOrTBuffer(TheDecl)) {
-    // make sure the type is a basic / numeric type
-    if (TheVarDecl) {
-      QualType TheQualTy = TheVarDecl->getType();
-      // a numeric variable or an array of numeric variables
-      // will inevitably end up in $Globals buffer
-      const clang::Type *TheBaseType = TheQualTy.getTypePtr();
-      while (TheBaseType->isArrayType())
-        TheBaseType = TheBaseType->getArrayElementTypeNoTypeQual();
-      if (TheBaseType->isIntegralType(S.getASTContext()) ||
-          TheBaseType->isFloatingType())
-        Flags.DefaultGlobals = true;
-    }
-  }
-
-  if (CBufferOrTBuffer) {
+  // Cbuffers and Tbuffers are HLSLBufferDecl types
+  if (HLSLBufferDecl *CBufferOrTBuffer = dyn_cast<HLSLBufferDecl>(TheDecl)) {
     Flags.Resource = true;
-    if (CBufferOrTBuffer->isCBuffer())
-      Flags.CBV = true;
-    else
-      Flags.SRV = true;
-  } else if (TheVarDecl) {
+    Flags.ResourceClass = CBufferOrTBuffer->isCBuffer()
+                              ? llvm::dxil::ResourceClass::CBuffer
+                              : llvm::dxil::ResourceClass::SRV;
+  }
+  // Samplers, UAVs, and SRVs are VarDecl types
+  else if (VarDecl *TheVarDecl = dyn_cast<VarDecl>(TheDecl)) {
     const HLSLResourceClassAttr *resClassAttr =
         getSpecifiedHLSLAttrFromVarDecl<HLSLResourceClassAttr>(TheVarDecl);
-
     if (resClassAttr) {
-      llvm::hlsl::ResourceClass DeclResourceClass =
-          resClassAttr->getResourceClass();
       Flags.Resource = true;
-      updateResourceClassFlagsFromDeclResourceClass(Flags, DeclResourceClass);
+      Flags.ResourceClass = resClassAttr->getResourceClass();
     } else {
       const clang::Type *TheBaseType = TheVarDecl->getType().getTypePtr();
       while (TheBaseType->isArrayType())
         TheBaseType = TheBaseType->getArrayElementTypeNoTypeQual();
-      if (TheBaseType->isArithmeticType())
+
+      if (TheBaseType->isArithmeticType()) {
         Flags.Basic = true;
-      else if (TheBaseType->isRecordType()) {
+        if (!isDeclaredWithinCOrTBuffer(TheDecl) &&
+            (TheBaseType->isIntegralType(S.getASTContext()) ||
+             TheBaseType->isFloatingType()))
+          Flags.DefaultGlobals = true;
+      } else if (TheBaseType->isRecordType()) {
         Flags.UDT = true;
         const RecordType *TheRecordTy = TheBaseType->getAs<RecordType>();
-        assert(TheRecordTy && "The Qual Type should be Record Type");
-        const RecordDecl *TheRecordDecl = TheRecordTy->getDecl();
-        // recurse through members, set appropriate resource class flags.
-        updateResourceClassFlagsFromRecordDecl(Flags, TheRecordDecl);
+        updateResourceClassFlagsFromRecordType(Flags, TheRecordTy);
       } else
         Flags.Other = true;
     }
+  } else {
+    llvm_unreachable("expected be VarDecl or HLSLBufferDecl");
   }
   return Flags;
 }
 
-enum class RegisterType { SRV, UAV, CBuffer, Sampler, C, I, Invalid };
+enum class RegisterType {
+  SRV = static_cast<int>(llvm::dxil::ResourceClass::SRV),
+  UAV = static_cast<int>(llvm::dxil::ResourceClass::UAV),
+  CBuffer = static_cast<int>(llvm::dxil::ResourceClass::CBuffer),
+  Sampler = static_cast<int>(llvm::dxil::ResourceClass::Sampler),
+  C,
+  I,
+  Invalid
----------------
hekota wrote:

I will add a `ResourceClass::Last` and a static assert. The `ResourceClass` values are explicitly [starting from 0](https://github.com/llvm/llvm-project/blob/c315d787e3680e7f48d9de0502bb83300b190f84/llvm/include/llvm/Support/DXILABI.h#L25) and very unlikely to change because we use the numeric values in [resource binding in DXIL](https://github.com/llvm/llvm-project/blob/897b00f3c563dd3f7b8f7263c41eaebb3520ec86/llvm/lib/Target/DirectX/DXILOpBuilder.cpp#L467). 

https://github.com/llvm/llvm-project/pull/106657