On Thu, Dec 9, 2010 at 8:55 PM, H.J. Lu <hjl.to...@gmail.com> wrote: > On Thu, Dec 9, 2010 at 6:29 PM, H.J. Lu <hjl.to...@gmail.com> wrote: >> On Wed, Dec 8, 2010 at 9:36 AM, H.J. Lu <hjl.to...@gmail.com> wrote: >>> On Wed, Dec 8, 2010 at 5:54 AM, H.J. Lu <hjl.to...@gmail.com> wrote: >>>> On Wed, Dec 8, 2010 at 1:19 AM, Andi Kleen <a...@firstfloor.org> wrote: >>>>>> On 12/07/2010 04:20 PM, Andi Kleen wrote: >>>>>>> >>>>>>> The only problem left is mixing of lto and non lto objects. this right >>>>>>> now is not handled. IMHO still the best way to handle it is to use >>>>>>> slim lto and then simply separate link the "left overs" after deleting >>>>>>> the LTO objects. This can be actually done with objcopy (with some >>>>>>> limitations), doesn't even need linker support. >>>>>>> >>>>>> >>>>>> Quite possibly a better way to deal with that is to provide a mechanism >>>>>> for encapsulating arbitrary binary code objects inside the LTO IR. >>>>> >>>>> Then you would need to teach your assembler and everything >>>> >>>> The magic section is generated by linker directly. No changes to >>>> assembler is required. >>>> >>>>> else that may generate ELF objects to generate this magic object. But why >>>>> not just ELF directly? that is what it is after all. >>>> >>>> My proposal isn't specific to ELF. >>>> >>>>> >>>>> To be honest I don't really see the point of all this complexity you >>>>> guys are proposing just to save fat LTO. Fat LTO is always a bad idea >>>>> because it's slow and does lots of redundant work. If LTO is to become >>>>> a more wide spread mode it has to go simply because of the poor >>>>> performance. >>>>> >>>>> With slim LTO passthrough is very straight-forward: simple pass >>>>> through every section that is not LTO and generate code for the LTO >>>>> sections. No new magic sections needed at all. >>>>> >>>> >>>> My proposal works on both fat and slim LTO objects. The idea is >>>> you can use "ld -r" on any combination of inputs and its output >>>> still works as before "ld -r". >>>> >>> >>> Here is the revised proposal. >>> >> >> The initial implementation of my proposal is available on hjl/lto-mixed >> branch at >> >> http://git.kernel.org/?p=devel/binutils/hjl/x86.git;a=summary >> >> Simple case works. More cleanups are needed. Feedbacks >> are welcome. >> > > I checked in patches to remove temporary files. > >
More fixes are checked in. I will try Linux kernel next. -- H.J.
