[clang] [clang][AST] fix dereference on class/struct layouts check. (PR #83686)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: David CARLIER (devnexen)

<details>
<summary>Changes</summary>

close #<!-- -->83671.

---
Full diff: https://github.com/llvm/llvm-project/pull/83686.diff


1 Files Affected:

- (modified) clang/lib/AST/RecordLayoutBuilder.cpp (+3-3) 


``````````diff
diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
index a3b7431f7ffd6d..195f17d2e5a42f 100644
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -205,15 +205,15 @@ void EmptySubobjectMap::ComputeEmptySubobjectSizes() {
 
   // Check the fields.
   for (const FieldDecl *FD : Class->fields()) {
+    const CXXRecordDecl *MemberDecl;
     const RecordType *RT =
         Context.getBaseElementType(FD->getType())->getAs<RecordType>();
 
-    // We only care about record types.
-    if (!RT)
+    // We only care about members layout.
+    if (!RT || !(MemberDecl = RT->getAsCXXRecordDecl()))
       continue;
 
     CharUnits EmptySize;
-    const CXXRecordDecl *MemberDecl = RT->getAsCXXRecordDecl();
     const ASTRecordLayout &Layout = Context.getASTRecordLayout(MemberDecl);
     if (MemberDecl->isEmpty()) {
       // If the class decl is empty, get its size.

``````````

</details>


https://github.com/llvm/llvm-project/pull/83686