Dear Sören,
we ran into a regression introduced by these changes. The regression manifests itself in a failing assertion in __deregister_frame_info_bases. The assertion failure was observed while using Chromium's `flatc` build system tool. The failing assertion is:unwind-dw2-fde.c:281 gcc_assert (in_shutdown || ob); [snip] However, I believe there is one more edge case that isn't being account for presently: If the inserted entry has a size of 0 (i.e. if range[1] - range[0] == 0) then the btree_insert call in __register_frame_info_bases will not insert anything. This is not accounted for in
> [snip]
Would be cool if this could be fixed on the GCC trunk.
thanks for the details analysis and the patch, it looks obviously correct for me. I can apply it to trunk, but we need approval from a gcc maintainer first.
But independent of your patch, do you have the test case available in some easily accessible form, for example a docker image or an automated build script? I ask because something odd is happening here, somebody registered a non-empty EH that does not contain a single unwind range. I am puzzled why anybody would do that, I would like to double check that this is indeed the intended behavior and not a bug somewhere else. Or if you have the test case at hand, it would be great if you could do a quick step through get_pc_range for the affected frame to double-check that the table is indeed empty and we don't miss an entry for some strange reason.
Best Thomas
