On Sep 13, 2016, Alexandre Oliva <aol...@redhat.com> wrote: >> I'm thinking your view numbers might be similar to my logical >> locations.
> I'm still digesting the information in the proposal and trying to > confirm they're roughly equivalent, or can be easily made so Considering they're limited to recommended breakpoints, I can confidently assert that they serve a significantly different purpose, and they would somewhat get in the way of the finer-grained view numbers. Consider, for example, that we want to represent in a location list that an operation that is NOT the recommended breakpoint for any (file,line,column) triplet modifies a register that used to hold the value of variable a, and that after the operation holds the value of variable b. With logical locations that represent only recommended breakpoints, location lists that were to refer to logical locations rather than PCs would not be able to represent that. Conversely, if location lists were to still refer to PCs rather than logical locations, we'd still be unable to represent in location lists the virtual advance from one line to another, since there isn't a different address to associate with the different location bindings. Another concern in my mind is the backward-compatibility of the new table. I'm very concerned about the disruption of the new split line number programs to existing debug information consumers; I'd much rather have something that extends existing information without breaking existing tools, enabling progressive adoption rather than flag days. But that's just me :-) I guess I'm also missing the motivation for all this disruption. I mean, I like the addition of context and subprogram, but I don't see why not add them as an extension to the exisiting line number program. I understand the argument about simplifying backtraces, but it seems to me that just having (back?)pointers from line number table to DIEs would accomplish a lot; I'm having a hard time believing that processing a somewhat smaller line number program even saves much in this case, since the odds that the points of the backtrace will coincide with the recommended breakpoints in the logical line table are pretty low. What am I missing something? -- 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 _______________________________________________ Dwarf-Discuss mailing list Dwarf-Discuss@lists.dwarfstd.org http://lists.dwarfstd.org/listinfo.cgi/dwarf-discuss-dwarfstd.org
