3 files changed, 26 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 5f04e8b..5a1ac5d 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -1013,6 +1013,7 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, const DICompositeType *CTy) {
     constructEnumTypeDIE(Buffer, CTy);
     break;
   case dwarf::DW_TAG_variant_part:
+  case dwarf::DW_TAG_variant:
   case dwarf::DW_TAG_structure_type:
   case dwarf::DW_TAG_union_type:
   case dwarf::DW_TAG_class_type:
@@ -1066,7 +1067,17 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, const DICompositeType *CTy) {
             addDiscriminant(Variant, CI,
                             DD->isUnsignedDIType(Discriminator->getBaseType()));
           }
-          constructMemberDIE(Variant, DDTy);
+          // If the variant holds a composite type with tag
+          // DW_TAG_variant, inline those members into the variant
+          // DIE.
+          if (auto *Composite =
+                  dyn_cast_or_null<DICompositeType>(DDTy->getBaseType());
+              Composite != nullptr &&
+              Composite->getTag() == dwarf::DW_TAG_variant) {
+            constructTypeDIE(Variant, Composite);
+          } else {
+            constructMemberDIE(Variant, DDTy);
+          }
         } else {
           constructMemberDIE(Buffer, DDTy);
         }
diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index d9cc49f..90da9f3 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -444,6 +444,19 @@ DIDerivedType *DIBuilder::createVariantMemberType(
       std::nullopt, std::nullopt, Flags, getConstantOrNull(Discriminant));
 }
 
+DIDerivedType *DIBuilder::createVariantMemberType(DIScope *Scope,
+                                                  DINodeArray Elements,
+                                                  Constant *Discriminant,
+                                                  DIType *Ty) {
+  auto *V = DICompositeType::get(VMContext, dwarf::DW_TAG_variant, {}, nullptr,
+                                 0, getNonCompileUnitScope(Scope), {}, 0, 0, 0,
+                                 DINode::FlagZero, Elements, 0, {}, nullptr);
+
+  trackIfUnresolved(V);
+  return createVariantMemberType(Scope, {}, nullptr, 0, 0, 0, 0, Discriminant,
+                                 DINode::FlagZero, V);
+}
+
 DIDerivedType *DIBuilder::createBitFieldMemberType(
     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
     uint64_t SizeInBits, uint64_t OffsetInBits, uint64_t StorageOffsetInBits,
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 83c1264..2cfd382 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -1343,6 +1343,7 @@ void Verifier::visitDICompositeType(const DICompositeType &N) {
               N.getTag() == dwarf::DW_TAG_enumeration_type ||
               N.getTag() == dwarf::DW_TAG_class_type ||
               N.getTag() == dwarf::DW_TAG_variant_part ||
+              N.getTag() == dwarf::DW_TAG_variant ||
               N.getTag() == dwarf::DW_TAG_namelist,
           "invalid tag", &N);