[clang] [Clang] Handle structs with inner structs and no fields (PR #89126)

[Eli Friedman via cfe-commits]

================
@@ -826,29 +826,31 @@ const FieldDecl *CodeGenFunction::FindFlexibleArrayMemberField(
     ASTContext &Ctx, const RecordDecl *RD, StringRef Name, uint64_t &Offset) {
   const LangOptions::StrictFlexArraysLevelKind StrictFlexArraysLevel =
       getLangOpts().getStrictFlexArraysLevel();
-  unsigned FieldNo = 0;
-  bool IsUnion = RD->isUnion();
+  uint32_t FieldNo = 0;
 
-  for (const Decl *D : RD->decls()) {
-    if (const auto *Field = dyn_cast<FieldDecl>(D);
-        Field && (Name.empty() || Field->getNameAsString() == Name) &&
+  if (RD->isImplicit())
+    return nullptr;
+
+  for (const FieldDecl *FD : RD->fields()) {
+    if ((Name.empty() || FD->getNameAsString() == Name) &&
         Decl::isFlexibleArrayMemberLike(
-            Ctx, Field, Field->getType(), StrictFlexArraysLevel,
+            Ctx, FD, FD->getType(), StrictFlexArraysLevel,
             /*IgnoreTemplateOrMacroSubstitution=*/true)) {
       const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
       Offset += Layout.getFieldOffset(FieldNo);
-      return Field;
+      return FD;
     }
 
-    if (const auto *Record = dyn_cast<RecordDecl>(D))
-      if (const FieldDecl *Field =
-              FindFlexibleArrayMemberField(Ctx, Record, Name, Offset)) {
+    QualType Ty = FD->getType();
+    if (!Ty->isPointerType() && (Ty->isStructureType() || Ty->isUnionType()))
----------------
efriedma-quic wrote:

```suggestion
    if (Ty->isRecordType())
```

https://github.com/llvm/llvm-project/pull/89126