On 11/21/18 7:19 AM, Tobias Burnus wrote:
Hello all,if a class contains any 'virtual ... = 0', it's an abstract class and for an abstract class, the destructor not added to the vtable. For a normal virtual ~class() { } that's not a problem as the class::~class() destructor will be generated during the parsing of the function. But for virtual ~class() = default; the destructor will be generated via mark_used via the vtable. If one now declares a derived class and uses it, the class::~class() is generated in that translation unit. Unless, #pragma interface/implementation is used. In that case, the 'default' destructor will never be generated. The following code seems to work both for the big code and for the example; without '#pragma implementation', the destructor is not generated for the example, only with. The patch survived boostrapping GCC with default languages on x86-64-gnu-linux and "make check-g++".* [One probably could get rid of some of the conditions for generating the code, e.g. TREE_USED and DECL_DEFAULTED_FN are probably not both needed; one might want to set some additional DECL to the fn decl.]
You can get at the destructor with CLASSTYPE_DESTRUCTOR rather than walking through TYPE_FIELDS. I'd also check DECL_DEFAULTED_IN_CLASS_P.
I'd also do this in maybe_emit_vtables rather than here, so that it only happens once per class.
Jason
