dblaikie added inline comments.
================ Comment at: clang/lib/AST/RecordLayoutBuilder.cpp:1891 + llvm::Triple Target = Context.getTargetInfo().getTriple(); + bool FieldPacked = (Packed && (!FieldClass || FieldClass->isPOD() || + Context.getLangOpts().getClangABICompat() <= ---------------- rsmith wrote: > `isPOD` is C++ standard specific, and our ABI rule really shouldn't be. Does > GCC use the C++98 rules here, the C++11 rules, or something else? (Hopefully > the GCC behavior doesn't change between `-std=c++98` and `-std=c++11`!) > > From a quick test, it looks like GCC doesn't pack fields whose types are > classes with base classes, even if they're trivially-copyable and > standard-layout, suggesting that it's probably using the C++98 POD rules. I /think/ `CXXRecordDecl::isPOD` doesn't use a language-varying definition, according to its documentation at least: https://github.com/llvm/llvm-project/blob/1e3a02162db20264e9615b1346420c8d199cb347/clang/include/clang/AST/DeclCXX.h#L1124 & the code that sets the field that the accessor returns looks, to me at least, consistent with that claim: https://github.com/llvm/llvm-project/blob/1e3a02162db20264e9615b1346420c8d199cb347/clang/lib/AST/DeclCXX.cpp#L983 But if there's another way I should spell this to make it more clear/correct, more test cases to add to show the difference between these definitions - I'm open to that... ================ Comment at: clang/lib/AST/RecordLayoutBuilder.cpp:1895 + Target.isPS4() || Target.isOSDarwin())) || + D->hasAttr<PackedAttr>(); ---------------- rsmith wrote: > Would it make sense to warn here if `Packed && !FieldPacked`, like GCC does? Probably? Happy to implement that in a follow-up. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D117616/new/ https://reviews.llvm.org/D117616 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits