https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97966
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:bca467e56fe111fa6d876656c60d5704065e83fe commit r11-6848-gbca467e56fe111fa6d876656c60d5704065e83fe Author: Marek Polacek <pola...@redhat.com> Date: Tue Jan 12 16:16:44 2021 -0500 c++: ICE with delayed noexcept and attribute used [PR97966] Another ICE with delayed noexcept parsing, but a bit gnarlier. A function definition marked with __attribute__((used)) ought to be emitted even when it is not referenced in the TU. For a member function template marked with __attribute__((used)) this means that it will be instantiated: in instantiate_class_template_1 we have 11971 /* Instantiate members marked with attribute used. */ 11972 if (r != error_mark_node && DECL_PRESERVE_P (r)) 11973 mark_used (r); It is not so surprising that this doesn't work well with delayed noexcept parsing: when we're processing the function template we delay the parsing, so the member "foo" is found, but then when we're instantiating it, "foo" hasn't yet been seen, which creates a discrepancy and a crash ensues. "foo" hasn't yet been seen because instantiate_class_template_1 just loops over the class members and instantiates right away. To make it work, this patch uses a vector to keep track of members marked with attribute used and uses it to instantiate such members only after we're done with the class; in particular, after we have called finish_member_declaration for each member. And we ought to be verifying that we did emit such members, so I've added a bunch of dg-finals. gcc/cp/ChangeLog: PR c++/97966 * pt.c (instantiate_class_template_1): Instantiate members marked with attribute used only after we're done instantiating the class. gcc/testsuite/ChangeLog: PR c++/97966 * g++.dg/cpp0x/noexcept63.C: New test.
