[CIR] Upstream RTTI Builder & RTTI for VTable Definitions (llvm#160002)

Upstream the RTTI builder with helpers and used them in the VTable
Definitions

Issue llvm#154992

Author: AmrDeveloper

clang/include/clang/CIR/MissingFeatures.h

@@ -37,6 +37,8 @@ struct MissingFeatures {
   static bool opGlobalDLLImportExport() { return false; }
   static bool opGlobalPartition() { return false; }
   static bool opGlobalUsedOrCompilerUsed() { return false; }
+  static bool setDSOLocal() { return false; }
+  static bool setComdat() { return false; }
 
   static bool supportIFuncAttr() { return false; }
   static bool supportVisibility() { return false; }

clang/lib/CIR/CodeGen/CIRGenBuilder.h

@@ -89,6 +89,11 @@ class CIRGenBuilderTy : public cir::CIRBaseBuilderTy {
     return cir::ConstRecordAttr::get(sTy, arrayAttr);
   }
 
+  cir::TypeInfoAttr getTypeInfo(mlir::ArrayAttr fieldsAttr) {
+    cir::ConstRecordAttr anonRecord = getAnonConstRecord(fieldsAttr);
+    return cir::TypeInfoAttr::get(anonRecord.getType(), fieldsAttr);
+  }
+
   std::string getUniqueAnonRecordName() { return getUniqueRecordName("anon"); }
 
   std::string getUniqueRecordName(const std::string &baseName) {

clang/lib/CIR/CodeGen/CIRGenCXXABI.h

@@ -114,6 +114,9 @@ class CIRGenCXXABI {
 
   virtual void emitRethrow(CIRGenFunction &cgf, bool isNoReturn) = 0;
 
+  virtual mlir::Attribute getAddrOfRTTIDescriptor(mlir::Location loc,
+                                                  QualType ty) = 0;
+
   /// Get the type of the implicit "this" parameter used by a method. May return
   /// zero if no specific type is applicable, e.g. if the ABI expects the "this"
   /// parameter to point to some artificial offset in a complete object due to