On Jan 25, 2018, Alexandre Oliva <aol...@redhat.com> wrote: > On Jan 24, 2018, Jakub Jelinek <ja...@redhat.com> wrote: >> On Tue, Dec 12, 2017 at 12:52:18AM -0200, Alexandre Oliva wrote: >>> + DW_LLE_GNU_view_pair = 0x09, >>> +#define DW_LLE_view_pair DW_LLE_GNU_view_pair
>> This looks wrong. The proposal has not been accepted yet, so you >> really can't know if DW_LLE_view_pair will be like that or whether it >> will have value of 9. Unfortunately, the DWARF standard doesn't specify a >> vendor range for DW_LLE_* values. I'd use 0xf0 or so, and don't pretend >> there is DW_LLE_view_pair at all, just use DW_LLE_GNU_view_pair everywhere. >> Jason, what do you think? > My reasoning was that, since we'd only emit this as an > explicitly-requested backward-incompatible extension to DWARF-5 (by > specifying -gdwarf-6 in this patch, but the option spelling could be > changed), any LLE number whatsoever would do. The point of the #define > was to write the code in GCC so that, once DW_LLE_view_pair was > standardized (if it ever was), we'd just set up an enum for it and we'd > be done, but that would only happen at DWARF6+ anyway, so we'd be able > to tell, since we'd then have actual DWARF6, rather than DWARF5 with an > incompatible extensions (which is what we emit with the current > -gdwarf-6 option; see below). Also... I have implemented DW_LLE_view_pair support in binutils's debug info dumping code, based on the proposed extension, and that has already been released, so changing the number in GCC would make it incompatible with the already-released binutils. You may notice I've renamed the GCC option to emit this extension in the latest version of the patch. -- Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/ You must be the change you wish to see in the world. -- Gandhi Be Free! -- http://FSFLA.org/ FSF Latin America board member Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer
