Clang is emitting no bounds info for the "x" in class c { char x[0]; char more_x[42]; }; This causes has_static_range for "x" to return false (lower bound is defaulted to zero, upper bound is unknown), which in turn causes is_dynamic_type to return true and we enter resolve_dynamic_type (which is just a wrapper on resolve_dynamic_type_internal). In the example at hand (I don't have an easy to provide testcase, at least not yet), the type is defined in another CU so what resolve_dynamic_type gets is an opaque type. We then hit this assert in resolve_dynamic_struct and crash: gdb_assert (TYPE_NFIELDS (type) > 0); resolve_dynamic_type_internal seems to not understand that check_typedef has (at least) two main purposes: 1) check for typedefs (duh ... :-)), 2) AND resolve opaque types. It's easy to understand this happening given how poorly named check_typedef is. static struct type * resolve_dynamic_type_internal (struct type *type, CORE_ADDR addr, int top_level) { struct type *real_type = check_typedef (type); struct type *resolved_type = type; const struct dynamic_prop *prop; CORE_ADDR value; if (!is_dynamic_type_internal (real_type, top_level)) return type; switch (TYPE_CODE (type)) { ... case TYPE_CODE_STRUCT: resolved_type = resolve_dynamic_struct (type, addr); break; } ... } Note that we've called check_typedef, BUT we're passing type to resolve_dynamic_struct not real_type. If type is an opaque type we in fact do want to pass real_type to resolve_dynamic_struct. Either that or call check_typedef again in resolve_dynamic_struct. Since this collection of functions is all just implementation detail for resolve_dynamic_type I'm ok with not sprinkling calls to check_typedef everywhere it might be needed (and in fact since the function is so badly named sprinkling it about doesn't improve readability). It would be reasonable to create a resolve_opaque_type function that handles this part of what check_typedef does, and use that instead, but I'm ok with just passing real_type to resolve_dynamic_struct here.
See also PR 17642
I do not see how this is clang specific. echo 'class c { char x[0]; char more_x[42]; };'|clang++ -c -g -o o.out -x c++ - gdb ./o.out does not crash for me. IMO there have to be at least two CUs to make there the stub type but then it is PR 17642. *** This bug has been marked as a duplicate of bug 17642 ***
Ahem. Just because I report a bug I'm seeing with clang does not mean I'm claiming the bug is clang specific. Sheesh.