I agree with Corey, it's much better to send it upstream first. I'd be more than willing to help you out with writing tests or taking a peek at the patch if you want! I'm acrichto on IRC
On Tue, Apr 22, 2014 at 12:43 AM, Vladimir Pouzanov <farcal...@gmail.com> wrote: > The problem is that mrc is generated unless target is thumb1, but cortex-m3 > is thumb2 that still doesn't support mrc: > http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka398.html, > so an additional check to ST->TargetTriple.Data is required to verify it's > not thumbv7m. > > Do I need to submit patch against https://github.com/rust-lang/llvm or send > it to upstream? > > > On Mon, Apr 21, 2014 at 6:34 PM, Vladimir Pouzanov <farcal...@gmail.com> > wrote: >> >> Hm, it seems to have precautions to stop mrc from materializing on Thumb1. >> I guess I need to take a better look into what's going wrong on my side. >> I'll see what I can do with that. >> >> >> On Mon, Apr 21, 2014 at 5:23 PM, Alex Crichton <a...@crichton.co> wrote: >>> >>> The split stack patches for ARM were recently upstreamed, and they >>> were modified when being upstreamed as well. Primarily the location of >>> the split stack is no longer at a magic address for thumb, but rather >>> it uses the same instruction as ARM (some thumb processors do indeed >>> have the coprocessor). More information is in the long thread starting >>> at the initial attempt to upstream [1]. >>> >>> For now you'll have to use no_split_stack because the thumb split >>> stack will always use a coprocessor, but I'm sure that the upstream >>> LLVM devs would be quite welcoming to tweaks to the slit-stack support >>> (I'd also be willing to help). You can find the initial commit for >>> support at rust-lang/llvm [2]. >>> >>> [1] - >>> http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20140224/205968.html >>> [2] - https://github.com/rust-lang/llvm/pull/4 >>> >>> On Mon, Apr 21, 2014 at 6:50 AM, Vladimir Pouzanov <farcal...@gmail.com> >>> wrote: >>> > Starting recently (no more than two weeks), rustc is generating a >>> > broken >>> > prologue for arm. Here's the sample assembly: >>> > 0x00000f44 <+0>: push {r4, r5} >>> > => 0x00000f46 <+2>: mrc 15, 0, r4, cr13, cr0, {3} >>> > 0x00000f4a <+6>: mov r5, sp >>> > 0x00000f4c <+8>: b.n 0xa78 <main+2616> >>> > 0x00000f4e <+10>: ands r4, r0 >>> > 0x00000f50 <+12>: cmp r4, r5 >>> > 0x00000f52 <+14>: bcc.n 0xf66 >>> > >>> > <_ZN7drivers3lcd6c1233244C12332$LT$$x27a$C$$x20S$C$$x20T$GT$.lcd..LCD5flush20h76589116290686712394v0.0E+34> >>> > 0x00000f54 <+16>: movs r4, #16 >>> > 0x00000f56 <+18>: movs r5, #0 >>> > 0x00000f58 <+20>: push {lr} >>> > 0x00000f5a <+22>: bl 0x19d8 <__morestack> >>> > 0x00000f5e <+26>: ldr.w lr, [sp], #4 >>> > 0x00000f62 <+30>: pop {r4, r5} >>> > 0x00000f64 <+32>: bx lr >>> > >>> > The problem is at 0x00000f46, where code tries to read from coprocessor >>> > 15 >>> > register 13, which is "process id register". Well, coprocessor 15 >>> > (actually, >>> > all of the coprocessors) are missing from my target thumbv7m-linux-eabi >>> > (with added flavour of -Ctarget-cpu=cortex-m3, which should be >>> > redundant >>> > anyway), so I'm getting hardfaults in every function that rust doesn't >>> > inline. >>> > >>> > Any ideas on what might be going wrong? I assume that this is actually >>> > llvm's fault, as llvm should not materialize machine code which is not >>> > available for target anyway. >>> > >>> > Wrapping everything in #[no_split_stack] is a temporary workaround and >>> > surely not a long-term strategy. >>> > >>> > -- >>> > Sincerely, >>> > Vladimir "Farcaller" Pouzanov >>> > http://farcaller.net/ >>> > >>> > _______________________________________________ >>> > Rust-dev mailing list >>> > Rust-dev@mozilla.org >>> > https://mail.mozilla.org/listinfo/rust-dev >>> > >> >> >> >> >> -- >> Sincerely, >> Vladimir "Farcaller" Pouzanov >> http://farcaller.net/ > > > > > -- > Sincerely, > Vladimir "Farcaller" Pouzanov > http://farcaller.net/ _______________________________________________ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
