> Am 10.02.2019 um 14:16 schrieb Tom Rini <tr...@konsulko.com>: > >> On Fri, Feb 08, 2019 at 08:58:18AM +0100, Alexander Graf wrote: >> >> >>> Am 08.02.2019 um 05:11 schrieb Simon Glass <s...@chromium.org>: >>> >>> Hi Alex, >>> >>>> On Sat, 2 Feb 2019 at 09:07, Alexander Graf <ag...@suse.de> wrote: >>>> >>>> >>>> >>>>> Am 02.02.2019 um 15:13 schrieb Simon Glass <s...@chromium.org>: >>>>> >>>>> Hi Alex, >>>>> >>>>>> On Thu, 31 Jan 2019 at 08:06, Alexander Graf <ag...@suse.de> wrote: >>>>>> >>>>>> The board_r init function was complaining that we are looping through >>>>>> an array, calling all our tiny init stubs sequentially via indirect >>>>>> function calls (which can't be speculated, so they are slow). >>>>> >>>>> Is this a compiler warning? Could you let me know what this is? >>>> >>>> It's the code comment I'm removing with this patch :). >>>> >>>>> >>>>>> >>>>>> The solution to that is pretty easy though. All we need to do is inline >>>>>> the function that loops through the functions and the compiler will >>>>>> automatically convert almost all indirect calls into direct inlined code. >>>>> >>>>> You mean it calls the functions one after the other without a >>>>> function-table array? >>>> >>>> Exactly. Magical, eh? It even inlines them! >>> >>> Yes it is surprising. I am also surprised that it reduces code size, >>> but I suppose that is why it does it. Presumably the inlining is what >>> does that. >> >> Yes, of course. With separate object files, the compiler can not >> inline anything at all, because it does not know how the function >> pointers get used. >> >> The alternative to this *might* be LTO, which we could think about as >> well. It should help reduce indirection and code size overall. But I >> don't know how well gold works with the linker scripts we have. > > I don't object to LTO but there's a LOT of groundwork before it's an > option. I think in addition to switching to gcc for ld, looking over an > old git stash from when I tried this last, we need to globally switch to > the "clang" method of keeping track of gd rather than how we do it > today.
Sounds like x86_64 could be an easy target for experimentation then? :) Alex > > -- > Tom _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
