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

[Damyan Pepper via cfe-commits]

================
@@ -985,88 +1034,85 @@ SemaHLSL::TakeLocForHLSLAttribute(const HLSLAttributedResourceType *RT) {
   return LocInfo;
 }
 
-// get the record decl from a var decl that we expect
-// represents a resource
-static CXXRecordDecl *getRecordDeclFromVarDecl(VarDecl *VD) {
-  const Type *Ty = VD->getType()->getPointeeOrArrayElementType();
-  assert(Ty && "Resource must have an element type.");
-
-  if (Ty->isBuiltinType())
-    return nullptr;
-
-  CXXRecordDecl *TheRecordDecl = Ty->getAsCXXRecordDecl();
-  assert(TheRecordDecl && "Resource should have a resource type declaration.");
-  return TheRecordDecl;
-}
-
+// Returns handle type of a resource, if the type is a resource
 static const HLSLAttributedResourceType *
-findAttributedResourceTypeOnField(VarDecl *VD) {
-  assert(VD != nullptr && "expected VarDecl");
-  if (RecordDecl *RD = getRecordDeclFromVarDecl(VD)) {
-    for (auto *FD : RD->fields()) {
-      if (const HLSLAttributedResourceType *AttrResType =
-              dyn_cast<HLSLAttributedResourceType>(FD->getType().getTypePtr()))
-        return AttrResType;
+findHandleTypeOnResource(const Type *Ty) {
+  // If Ty is a resource class, the first field must
+  // be the resource handle of type HLSLAttributedResourceType
+  if (RecordDecl *RD = Ty->getAsCXXRecordDecl()) {
+    if (!RD->fields().empty()) {
+      const auto &FirstFD = RD->fields().begin();
+      return dyn_cast<HLSLAttributedResourceType>(
+          FirstFD->getType().getTypePtr());
     }
   }
   return nullptr;
 }
 
-// Iterate over RecordType fields and return true if any of them matched the
-// register type
-static bool ContainsResourceForRegisterType(Sema &S, const RecordType *RT,
-                                            RegisterType RegType) {
-  llvm::SmallVector<const Type *> TypesToScan;
-  TypesToScan.emplace_back(RT);
-
-  while (!TypesToScan.empty()) {
-    const Type *T = TypesToScan.pop_back_val();
-    while (T->isArrayType())
-      T = T->getArrayElementTypeNoTypeQual();
-    if (T->isIntegralOrEnumerationType() || T->isFloatingType()) {
-      if (RegType == RegisterType::C)
-        return true;
+// Walks though the global variable declaration, collects all resource binding
+// requirements and adds them to Bindings
+void SemaHLSL::collectResourcesOnUserRecordDecl(const VarDecl *VD,
+                                                const RecordType *RT) {
+  const RecordDecl *RD = RT->getDecl();
+  for (FieldDecl *FD : RD->fields()) {
+    const Type *Ty = FD->getType()->getUnqualifiedDesugaredType();
+
+    // Unwrap arrays
+    // FIXME: Calculate array size while unwrapping
+    assert(!Ty->isIncompleteArrayType() &&
+           "incomplete arrays inside user defined types are not supported");
+    while (Ty->isConstantArrayType()) {
+      const ConstantArrayType *CAT = cast<ConstantArrayType>(Ty);
+      Ty = CAT->getElementType()->getUnqualifiedDesugaredType();
     }
-    const RecordType *RT = T->getAs<RecordType>();
-    if (!RT)
+
+    if (!Ty->isRecordType())
       continue;
 
-    const RecordDecl *RD = RT->getDecl();
-    for (FieldDecl *FD : RD->fields()) {
-      const Type *FieldTy = FD->getType().getTypePtr();
-      if (const HLSLAttributedResourceType *AttrResType =
-              dyn_cast<HLSLAttributedResourceType>(FieldTy)) {
-        ResourceClass RC = AttrResType->getAttrs().ResourceClass;
-        if (getRegisterType(RC) == RegType)
-          return true;
-      } else {
-        TypesToScan.emplace_back(FD->getType().getTypePtr());
-      }
+    if (const HLSLAttributedResourceType *AttrResType =
+            findHandleTypeOnResource(Ty)) {
+      // Add a new DeclBindingInfo to Bindings if it does not already exist
+      ResourceClass RC = AttrResType->getAttrs().ResourceClass;
+      DeclBindingInfo *DBI = Bindings.getDeclBindingInfo(VD, RC);
+      if (!DBI)
----------------
damyanp wrote:

At first glance something seems off about that, but without getting the actual array / size implementation in there it's hard to tell.

If there's no test coverage that exercises this case then it might be better to remove the `if` guard so that it doesn't accidentally mask some other problem we weren't expecting.

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