[clang] [HLSL] Add implicit resource element type concepts to AST (PR #112600)

[Helena Kotas via cfe-commits]

================
@@ -483,10 +581,105 @@ static BuiltinTypeDeclBuilder setupBufferType(CXXRecordDecl *Decl, Sema &S,
       .addDefaultHandleConstructor(S, RC);
 }
 
+BinaryOperator *constructSizeOfLEQ16Expr(ASTContext &Context,
+                                         SourceLocation NameLoc,
+                                         TemplateTypeParmDecl *T) {
+  // Obtain the QualType for 'unsigned long'
+  QualType UnsignedLongType = Context.UnsignedLongTy;
+
+  // Create a QualType that points to this TemplateTypeParmDecl
+  QualType TType = Context.getTypeDeclType(T);
+
+  // Create a TypeSourceInfo for the template type parameter 'T'
+  TypeSourceInfo *TTypeSourceInfo =
+      Context.getTrivialTypeSourceInfo(TType, NameLoc);
+
+  UnaryExprOrTypeTraitExpr *sizeOfExpr = new (Context) UnaryExprOrTypeTraitExpr(
+      UETT_SizeOf, TTypeSourceInfo, UnsignedLongType, NameLoc, NameLoc);
+
+  // Create an IntegerLiteral for the value '16' with size type
+  QualType SizeType = Context.getSizeType();
+  llvm::APInt SizeValue = llvm::APInt(Context.getTypeSize(SizeType), 16);
+  IntegerLiteral *SizeLiteral =
+      new (Context) IntegerLiteral(Context, SizeValue, SizeType, NameLoc);
+
+  QualType BoolTy = Context.BoolTy;
+
+  BinaryOperator *binaryOperator =
+      BinaryOperator::Create(Context, sizeOfExpr, // Left-hand side expression
+                             SizeLiteral,         // Right-hand side expression
+                             BO_LE,               // Binary operator kind (<=)
+                             BoolTy,              // Result type (bool)
+                             VK_LValue,           // Value kind
+                             OK_Ordinary,         // Object kind
+                             NameLoc,             // Source location of operator
+                             FPOptionsOverride());
+
+  return binaryOperator;
+}
+
+Expr *constructTypedBufferConstraintExpr(Sema &S, SourceLocation NameLoc,
+                                         TemplateTypeParmDecl *T) {
+  ASTContext &Context = S.getASTContext();
+
+  // first get the "sizeof(T) <= 16" expression, as a binary operator
+  BinaryOperator *SizeOfLEQ16 = constructSizeOfLEQ16Expr(Context, NameLoc, T);
+  // TODO: add the 'builtin_hlsl_is_typed_resource_element_compatible' builtin
+  // and return a binary operator that evaluates the builtin on the given
+  // template type parameter 'T'.
+  // Defined in issue https://github.com/llvm/llvm-project/issues/113223
+  return SizeOfLEQ16;
+}
+
+ConceptDecl *constructTypedBufferConceptDecl(Sema &S, NamespaceDecl *NSD) {
+  ASTContext &Context = S.getASTContext();
+  DeclContext *DC = NSD->getDeclContext();
+  SourceLocation DeclLoc = SourceLocation();
+
+  IdentifierInfo &IsTypedResourceElementCompatibleII =
+      Context.Idents.get("__is_typed_resource_element_compatible");
----------------
hekota wrote:

Nit - move this just before DeclName declaration, or better yet use `Context.Idents.get("__is_typed_resource_element_compatible")` directly in the DeclarationName constructor.
It makes it easier to read when variables are declared closer to where they are is used. 

https://github.com/llvm/llvm-project/pull/112600