https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84213
--- Comment #10 from Pierre-Marie de Rodat <derodat at adacore dot com> --- (In reply to Richard Biener from comment #8) > Yeah, setting DECL_PRESERVE_P would make it possible to add the > location late since we'd not remove the decl. Currently it's simply > gone and the early dwarf2out_"late"_global_decl is the last thing > we see from it... Ok, understood. > Currently struggling in getting a debuggable gnat1 built .. it looks > like ./configure --enable-languages=c++,ada --disable-bootstrap > no longer works with a host compiler that doesn't understand some > C++ specs that appear to be used (GCC 4.8). I’m using GCC 7.2.1. It’s odd that you get this issue only with gnat1, though… (In reply to Richard Biener from comment #9) > Another possibility would be to add the info symbolically by refering to the > early DIE of the other entity. Not sure if that works for the Ada cases? > We have > DW_OP_GNU_variable_value but in this case we want the DIEs address. In the original ADa use case, there is no other entity: the variable for which we want to emit a location is around only for its name, so instead of allocating a memory slot for it, we produce a “dummy” location (DW_OP_const1s: -1). So I don’t know: would what you have in mind work? (just keeping producing a location is enough for Ada, I think) > Btw, if you compile any of your testcases for the issue with -g -flto > can you verify if the generated object files contain relocations in the > early LTO debug sections? Those should not refer to real symbols... > else the problem will manifest with Ada as well. I’m confused: is this query for myself or for one Martin? ;-) > So I think we do have to revert the revision in question (or put in the > above hack). Either way, in the end we need a solution that fixes the SPEC build error and that does not make Ada debugging regress. :-) I’m still not familiar with LTO and how early/late passes are supposed to work, so I lack judgment about what is a hack and what isn’t. Do you think we can find a clean way to delay location production from the “early late” pass to the “truly late” one?
