[clang] [clang][CGRecordLayout] Remove dependency on isZeroSize (PR #96422)

[Eli Friedman via cfe-commits]

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@@ -310,6 +310,41 @@ bool CodeGen::isEmptyRecord(ASTContext &Context, QualType T, bool AllowArrays,
   return true;
 }
 
+bool CodeGen::isEmptyFieldForLayout(const ASTContext &Context,
+                                    const FieldDecl *FD) {
+  if (FD->isZeroLengthBitField(Context))
+    return true;
+
+  if (FD->isUnnamedBitField())
+    return false;
+
+  return isEmptyRecordForLayout(Context, FD->getType());
+}
+
+bool CodeGen::isEmptyRecordForLayout(const ASTContext &Context, QualType T) {
+  const RecordType *RT = T->getAs<RecordType>();
+  if (!RT)
+    return false;
+
+  const RecordDecl *RD = RT->getDecl();
+
+  // If this is a C++ record, check the bases first.
+  if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
+    if (CXXRD->isPolymorphic())
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efriedma-quic wrote:

`isDynamicClass()`, to also check for virtual base classes

https://github.com/llvm/llvm-project/pull/96422