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

[Helena Kotas 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)
----------------
hekota wrote:

This can happen when you have multiple resources of the same class in the same used record type. In that case we would update the size of the binding. This is how the code looked like before I removed the size calculations because they were not tested:

```
// Add a new DeclBindingInfo to Bindings. Update the binding size if
// a binding info already exists (there are multiple resources of same
// resource class in this user decl)
if (auto *DBI = Bindings.getDeclBindingInfo(VD, RC))
  DBI->Size += Size * ArraySize;
else
  Bindings.addDeclBindingInfo(VD, RC, Size);
```

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