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. -- H.J.
