On 30/11/11 21:34, Tom Tromey wrote: >>>>>> "Stephan" == Stephan Bergmann <sberg...@redhat.com> writes: > > Stephan> On 11/30/2011 05:37 PM, Lionel Elie Mamane wrote: >>> Any opinion about this patch? I have it in my local repo, and it helps >>> me when running under gdb, as gdb now knows about macros! > > Stephan> Would -ggdb3 excessively increase object size compared to -ggdb2? > > The short answer is yes, but there is a more complicated answer. > > First, one must consider the tradeoffs. I always use -g3 when building > gdb, because gdb uses macros fairly heavily, and because I just don't > care about the extra space. I prefer the convenience. YMMV of course, > and I don't know enough about LibreOffice to offer an opinion.
an interesting data point: LO tree built with gcc 4.6.2 -g takes up 23G. extrapolating from Lubos' mail that -ggdb3 takes 4 times as much space the problem should be obvious :-/ my vague memory says without debug it's something like 8G, the sources+repo ~2G. > In a recent-enough GCC (I don't know if it made 4.6, but anyway I think > it is in Fedora 16), there is a GNU extension to how macro information > is represented. This extension greatly reduces the size of the macro > information. > > If you really want to shrink debuginfo, use -gdwarf-4 and > -fdebug-types-section. The former has been in GCC for a while, I don't > remember when the latter was added. These options cause debuginfo for > most big types to be shared across compilation units, a huge size win. > This also makes gdb use less memory. that sounds very useful, especially the "gdb using less memory" bit; i assume it ought to start faster then as well. still i'm not sure if it would get us to the point where -ggdb3 is usable for the whole LO: if i understand correctly -fdebug-types-section would only affect the size of libraries, not of objects; for the sw module i currently have 767M of objects and 240M of libs. > The downside of this feature is that not all tools have been upgraded to > understand it. gdb works fine, but the 7 dwarves, and systemtap, and I > think valgrind, will barf. They will all come around eventually, though > I am not sure when. > > Tom so i guess we should wait until valgrind understands this feature too before enabling it. thanks for keeping us up to date, michael _______________________________________________ LibreOffice mailing list LibreOffice@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/libreoffice
