https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99283
--- Comment #17 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Nathan Sidwell <nat...@gcc.gnu.org>: https://gcc.gnu.org/g:584731ecedf09c2c067913c4af9ed0a30cf19e8d commit r11-7950-g584731ecedf09c2c067913c4af9ed0a30cf19e8d Author: Nathan Sidwell <nat...@acm.org> Date: Thu Apr 1 05:25:53 2021 -0700 c++: inter-cluster import order [PR 99283] I finally managed to reduce the testcase without hitting other bugs. This problem is caused by discovering a duplicate in the middle of reading in the entity in question. I had thougt the import seeding at the beginning of a cluster prevented that, but it is insufficient. Specifically an earlier cluster in the same module can cause the import of a duplicate. Although clusters within a module are well-ordered, there is no ordering between clusters of one module and clusters of another module. And thus we can get duplicate declaration loops. This prevents the problem by also seeding references to earlier clusters in the same module. As the FIXME notes, it is sufficient to reference a single entity in any particular earlier cluster, plus, we also could determine the implicit dependencies and prune that seeding even further. I do not do that -- it decrease the loading that will happen, but would reduce the serialization size. As ever, let's get correctness first. PR c++/99283 gcc/cp/ * module.cc (trees_out::decl_node): Adjust importedness reference assert. (module_state::intercluster_seed): New. Seed both imports and inter-cluster references. Broken out of ... (module_state::write_cluster): ... here. Call it. gcc/testsuite/ * g++.dg/modules/pr99283-6.h: New. * g++.dg/modules/pr99283-6_a.H: New. * g++.dg/modules/pr99283-6_b.H: New. * g++.dg/modules/pr99283-6_c.C: New. * g++.dg/modules/hdr-init-1_c.C: Adjust scan. * g++.dg/modules/indirect-3_c.C: Adjust scan. * g++.dg/modules/indirect-4_c.C: Adjust scan. * g++.dg/modules/lambda-3_b.C: Adjust scan. * g++.dg/modules/late-ret-3_c.C: Adjust scan. * g++.dg/modules/pr99425-1_b.H: Adjust scan. * g++.dg/modules/pr99425-1_c.C: Adjust scan.
