On Fri, Feb 18, 2011 at 12:11 AM, Jan Beulich <jbeul...@novell.com> wrote: >>>> On 17.02.11 at 18:59, "H.J. Lu" <hjl.to...@gmail.com> wrote: >> On Thu, Feb 17, 2011 at 8:11 AM, Jan Beulich <jbeul...@novell.com> wrote: >>>>>> On 17.02.11 at 16:49, "H.J. Lu" <hjl.to...@gmail.com> wrote: >>>> On Thu, Feb 17, 2011 at 7:44 AM, Jan Hubicka <hubi...@ucw.cz> wrote: >>>>>> > According to Mozilla folks however REL+RELA scheme used by EABI leads >>>>>> > to significandly smaller libxul.so size >>>>>> > >>>>>> > According to http://glandium.org/blog/?p=1177 the difference is about >>>>>> > 4-5MB >>>>>> > (out of approximately 20-30MB shared lib) >>>>>> >>>>>> This is orthogonal to x32 psABI. >>>>> >>>>> Understood. I am just pointing out that x86-64 Mozilla suffers from >>>>> startup >>>>> problems (extra 5MB of disk read needed) compared to both x86 and ARM EABI >>>>> because x86-64 ABI is RELA only. If x86-64 ABI was REL+RELA like EABI is, >>>>> we >>>>> would not have this problem here. >>>>> >>>> >>>> If people want to see REL+RELA in x32, they have to contribute codes. >>> >>> That's exactly the wrong way round: First the specification has to allow >>> for (but not require) it, and only then does it make sense to write code. >>> >> >> No, it has to be supported at least by static linker and dynamic >> linker. Otherwise, no one can use it. > > I'm afraid I have to disagree: ELF (and the psABI) is not specific to > a particular OS, and hence it allowing something doesn't mean the > OS ABI may not restrict it. Hence the psABI first has to at least not > forbid something (as it currently does for REL on x86-64), in order > for an implementation of that something to make sense. > > Jan > >
How about only allowing REL relocations in executables and DSOes? BTW, the psABI source is available on hjl/x32 banch at http://git.kernel.org/?p=devel/binutils/hjl/x86-64-psabi.git;a=summary -- H.J.
