Thanks, I will check what I can do with collect2. LTO seems to save 6-9% code size for applications I tested and should be very useful for us.
Bingfeng > -----Original Message----- > From: Richard Guenther [mailto:richard.guent...@gmail.com] > Sent: 28 April 2010 10:33 > To: Bingfeng Mei > Cc: gcc@gcc.gnu.org > Subject: Re: LTO question > > On Tue, Apr 27, 2010 at 6:30 PM, Bingfeng Mei > <b...@broadcom.com> wrote: > > Hello, > > I have been playing with LTO. I notice that LTO doesn't work when > > object files are achived into static library files and the final > > binary is linked against them, although these object files > are compiled > > with -flto and I can see all the lto related sections in .a files. > > Is this what is described in LTO Wiki page? > > > > "As an added feature, LTO will take advantage of the plugin feature > > in gold. This allows the compiler to pick up object files that may > > have been stored in library archives. " > > > > So do I have to use gold to solve this issue? > > Yes. Or you fix collect2 to do processing of archives and hand > lto1 the required information (it expects archive components > with LTO bytecode like archiv...@offset with offset being the > offset of the .o file with LTO bytecode inside the archive). See > lto/lto-elf.c:lto_obj_file_open for "details". > > Richard. > > > Many thanks, > > Bingfeng > > > >
