[CIR][CIRGen][TBAA] Add support for struct types

clang/include/clang/CIR/Dialect/IR/CIRTBAAAttrs.td

@@ -50,9 +50,35 @@ def CIR_TBAATagAttr : CIR_Attr<"TBAATag", "tbaa_tag", [], "TBAAAttr"> {
   let assemblyFormat = "`<` struct(params) `>`";
 }
 
+def CIR_TBAAStructAttr : CIR_Attr<"TBAAStruct", 
+                                  "tbaa_struct", [], "TBAAAttr"> {
+  let summary = "Describes a struct type in TBAA";
+
+  let parameters = (ins CIR_StructType : $type);
+
+  let description = [{
+    Define a TBAA struct attribute.
+
+    Example:
+    ```mlir
+    // CIR_TBAAStructAttr
+    !ty_StructA = !cir.struct<struct "StructA" {!u16i, !u32i, !u16i, !u32i} #cir.record.decl.ast>
+    !ty_StructS = !cir.struct<struct "StructS" {!u16i, !u32i} #cir.record.decl.ast>
+    #tbaa_struct = #cir.tbaa_struct<type = !ty_StructA>
+    #tbaa_struct1 = #cir.tbaa_struct<type = !ty_StructS>
+    ```
+
+    See the following link for more details:
+    https://llvm.org/docs/LangRef.html#tbaa-metadata
+  }];
+
+  let assemblyFormat = "`<` struct(params) `>`";
+}
+
 def CIR_AnyTBAAAttr : AnyAttrOf<[
   CIR_TBAAAttr, 
   CIR_TBAAOmnipotentChar, 
-  CIR_TBAAScalarAttr, 
+  CIR_TBAAScalarAttr,
+  CIR_TBAAStructAttr,
   CIR_TBAATagAttr
 ]>;

clang/include/clang/CIR/MissingFeatures.h

@@ -59,7 +59,7 @@ struct MissingFeatures {
   static bool emitTypeCheck() { return false; }
   static bool tbaa() { return false; }
   static bool tbaaStruct() { return false; }
-  static bool tbaaTagForStruct() { return false; }
+  static bool tbaaTagForStruct() { return true; }
   static bool tbaaTagForEnum() { return false; }
   static bool tbaaTagForBitInt() { return false; }
   static bool tbaaVTablePtr() { return false; }

clang/lib/CIR/CodeGen/CIRGenTBAA.cpp

@@ -203,8 +203,8 @@ cir::TBAAAttr CIRGenTBAA::getTypeInfo(clang::QualType qty) {
   // be considered may-alias too.
   // function.
   if (isValidBaseType(qty)) {
-    assert(!cir::MissingFeatures::tbaaTagForStruct());
-    return tbaa_NYI(mlirContext);
+    assert(cir::MissingFeatures::tbaaTagForStruct());
+    return cir::TBAAStructAttr::get(mlirContext, types.convertType(qty));
   }
 
   const clang::Type *ty = astContext.getCanonicalType(qty).getTypePtr();
@@ -248,7 +248,7 @@ mlir::ArrayAttr CIRGenTBAA::getTBAAStructInfo(clang::QualType qty) {
 }
 
 cir::TBAAAttr CIRGenTBAA::getBaseTypeInfo(clang::QualType qty) {
-  return tbaa_NYI(mlirContext);
+  return cir::TBAAStructAttr::get(mlirContext, types.convertType(qty));
 }
 
 cir::TBAAAttr CIRGenTBAA::getAccessTagInfo(TBAAAccessInfo tbaaInfo) {

clang/lib/CIR/Dialect/IR/CIRDialect.cpp

@@ -109,7 +109,7 @@ struct CIROpAsmDialectInterface : public OpAsmDialectInterface {
     }
     return TypeSwitch<Attribute, AliasResult>(attr)
         .Case<cir::TBAAAttr, cir::TBAAOmnipotentCharAttr, cir::TBAAScalarAttr,
-              cir::TBAATagAttr>([&](auto attr) {
+              cir::TBAAStructAttr, cir::TBAATagAttr>([&](auto attr) {
           os << decltype(attr)::getMnemonic();
           return AliasResult::OverridableAlias;
         })

clang/lib/CIR/Dialect/Transforms/TargetLowering/LowerModule.cpp

@@ -23,6 +23,7 @@
 #include "mlir/IR/Attributes.h"
 #include "mlir/IR/BuiltinAttributes.h"
 #include "mlir/IR/PatternMatch.h"
+#include "mlir/Support/LLVM.h"
 #include "mlir/Support/LogicalResult.h"
 #include "clang/CIR/Target/AArch64.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -240,6 +241,12 @@ createLowerModule(mlir::ModuleOp module, mlir::PatternRewriter &rewriter) {
   // Create context.
   cir_cconv_assert(!cir::MissingFeatures::langOpts());
   clang::LangOptions langOpts;
+  if (auto langAttr = mlir::cast_if_present<cir::LangAttr>(
+          module->getAttr(cir::CIRDialect::getLangAttrName()))) {
+    if (langAttr.isCXX()) {
+      langOpts.CPlusPlus = true;
+    }
+  }
 
   // FIXME(cir): This just uses the default code generation options. We need to
   // account for custom options.