https://gcc.gnu.org/bugzilla/show_bug.cgi?id=48776
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Mikael Morin <mik...@gcc.gnu.org>: https://gcc.gnu.org/g:d58150452976c4ca65ddc811fac78ef956fa96b0 commit r14-3572-gd58150452976c4ca65ddc811fac78ef956fa96b0 Author: Mikael Morin <mik...@gcc.gnu.org> Date: Wed Aug 30 14:18:56 2023 +0200 fortran: Restore interface to its previous state on error [PR48776] Keep memory of the content of the current interface body being parsed and restore it to its previous state if it has been modified at the time a parse attempt fails. This fixes memory errors and random segmentation faults caused by dangling symbol pointers kept in interfaces' linked lists of symbols. If a parsing attempt fails and symbols are freed, they should also be removed from the current interface linked list. As the list of symbol is a linked list, and parsing only adds new symbols to the head of the list, all that is needed to track the previous content of the list is a pointer to its previous head. This adds such a pointer, and the restoration of the list of symbols to that pointer on error. PR fortran/48776 gcc/fortran/ChangeLog: * gfortran.h (gfc_drop_interface_elements_before): New prototype. (gfc_current_interface_head): Return a reference to the pointer. * interface.cc (gfc_current_interface_head): Ditto. (free_interface_elements_until): New function, generalizing gfc_free_interface. (gfc_free_interface): Use free_interface_elements_until. (gfc_drop_interface_elements_before): New function. * parse.cc (current_interface_ptr, previous_interface_head): New static variables. (current_interface_valid_p, get_current_interface_ptr): New functions. (decode_statement): Initialize previous_interface_head. (reject_statement): Restore current interface pointer to point to previous_interface_head. gcc/testsuite/ChangeLog: * gfortran.dg/interface_procedure_1.f90: New test.
