On September 15, 2015 4:25:37 PM GMT+02:00, Jason Merrill <ja...@redhat.com> wrote: >On 08/27/2015 09:36 AM, Richard Biener wrote: >> >> With the passes.c hunk in the patch below we FAIL assembly comparison >> of g++.dg/pch/system-[12].C because with PCH we have computed >> DECL_ASSEMBLER_NAME and thus appended DW_AT_linkage_name early during >> PCH generation while without PCH we compute it lazily and end up >> appending DW_AT_specification earlier. Thus we have swapped dwarf >> attribute order and assembly comparison fails. >> >> Clearly this kind of "IL" changes dependent on whether we are writing >> a PCH file is going to cause differences down the food chain. >> (there is another case in instantiate_decl calling >add_pending_template >> dependent on pch_file) >> >> Now a simple solution is to simply not do that (mangle decls). >Another >> would be to always mangle decls where we now do so conditional on >PCH. >> Another soulution is to declare we don't care about assembly >differences >> with/without using PCH and remove assembly comparison from the >> testsuite harness. > >Hmm, what if we walk through the symtab and mangle everything later, >when we're about to write the PCH? That should still get the benefit >of >doing the mangling work only once, without changing the order of the >attributes.
That might work if we can get at all relevant decls that way. If not we can populate a pointer-set from the function and walk that before writing the PCH. I can do that if you prefer, I just didn't know if we care about PCH performance enough to worry. Thanks, Richard. > >Jason
