No. See https://github.com/mozilla/rust/pull/8955 and https://github.com/mozilla/rust/issues/11871 for discussion. You can stub out morestack but that won't remove the stack size checks. It's sanest to just compile the IR yourself (the stack checking is a target-specific machine pass, which is why it shows up with --emit asm but not --emit bc)
On Sun, Mar 23, 2014 at 2:09 PM, Vladimir Pouzanov <[email protected]> wrote: > So it doesn't work in the end. > > rustc --emit bc with flags set for cortex-m0 provides exact same bc with > only difference in target triple (which makes perfect sense) > > However, replacing llc step with rustc --emit asm provides a different > assembler file, which requires __morestack. > > Should I expect rustc to generate freestanding code given some additional > options? > > > On Sun, Mar 23, 2014 at 5:55 PM, Vladimir Pouzanov <[email protected]> > wrote: >> >> Nevermind, I lost -O somewhere in between copying and pasting command line >> flags. Optimised version doesn't have any morestack references (which is >> strange concept though). >> >> >> On Sun, Mar 23, 2014 at 5:44 PM, Vladimir Pouzanov <[email protected]> >> wrote: >>> >>> Figured out I can use --target thumbv6m-linux-eabi, which implies >>> -mthumb. Now the problem is that if I use >>> >>> rustc --target thumbv6m-linux-eabi -O --emit obj main.rs -o main.o >>> >>> instead of three-step process I mentioned before, I get a valid object >>> file for cortex-m0, but functions have big prologues and symbol table is >>> much bigger: >>> >>> U STACK_LIMIT >>> U _GLOBAL_OFFSET_TABLE_ >>> 00000000 D _ZN20_rust_crate_map_main16ad67637f924a5c794v0.0E >>> 00000008 r _ZN2hw11GPIO_PIN_NO20hb0b70c1482b61788Gaa4v0.0E >>> 00000000 r _ZN2hw12GPIO_DIR_REG20hb0b70c1482b61788yaa4v0.0E >>> 00000004 r _ZN2hw12GPIO_REG_VAL20hb0b70c1482b61788Caa4v0.0E >>> 00000078 t _ZN4main10__rust_abiE >>> 00000000 t _ZN4wait20h53ffb23463e08f19Maa4v0.0E >>> U __aeabi_unwind_cpp_pr0 >>> U __morestack >>> 0000004c T main >>> >>> vs. >>> >>> 00000000 D _ZN23_rust_crate_map_main.c016ad67637f924a5c794v0.0E >>> 00000000 T main >>> >>> in the initial version. Also, I now need to provide __morestack (no idea >>> what's that about). >>> >>> >>> On Sun, Mar 23, 2014 at 5:17 PM, Alex Crichton <[email protected]> wrote: >>>> >>>> You should be able to assemble standalone objects for any triple >>>> through rustc itself, you'll likely have to specify a different linker >>>> or assembler though: >>>> >>>> rustc foo.rs --target arm-non-linux-gnueabi \ >>>> -C linker=arm-non-linux-gnueabi-ld \ >>>> -C ar=arm-non-linux-gnueabi-ar >>>> >>>> As you discovered, you can pass through arguments to LLVM via the "-C >>>> llvm-args=foo" command line option to rustc. If you get complaints >>>> that it's an unknown command line argument, it's LLVM telling you >>>> those complaints, not rustc. >>>> >>>> On Sun, Mar 23, 2014 at 8:54 AM, Vladimir Pouzanov <[email protected]> >>>> wrote: >>>> > I'm trying to experiment with rust and some embedded code. Currently I >>>> > have >>>> > to do a three-pass compilation: >>>> > >>>> > rustc --target arm-linux-eabi -O --emit bc main.rs -o main.bc >>>> > llc -mtriple arm-none-eabi -march=thumb -mcpu=cortex-m0 main.bc -o >>>> > main.s >>>> > arm-none-linux-gnueabi-as main.s -o main.o >>>> > >>>> > First, I'm not sure how relevant is --target flag for rustc. I seems >>>> > to >>>> > change target datalayout/triple in generated bc, but that should be >>>> > overriden by llc -mtriple anyway, right? >>>> > >>>> > Second, I can pass -Ctarget-cpu=cortex-m0, but I cannot pass down >>>> > -march=thumb, tried this way: -Cllvm-args='--march=thumb', failed with >>>> > "rustc: Unknown command line argument '--march=thumb'". >>>> > >>>> > Any hints on how can I drop explicit llc and as steps here? >>>> > >>>> > -- >>>> > Sincerely, >>>> > Vladimir "Farcaller" Pouzanov >>>> > http://farcaller.net/ >>>> > >>>> > _______________________________________________ >>>> > Rust-dev mailing list >>>> > [email protected] >>>> > https://mail.mozilla.org/listinfo/rust-dev >>>> > >>> >>> >>> >>> >>> -- >>> Sincerely, >>> Vladimir "Farcaller" Pouzanov >>> http://farcaller.net/ >> >> >> >> >> -- >> Sincerely, >> Vladimir "Farcaller" Pouzanov >> http://farcaller.net/ > > > > > -- > Sincerely, > Vladimir "Farcaller" Pouzanov > http://farcaller.net/ > > _______________________________________________ > Rust-dev mailing list > [email protected] > https://mail.mozilla.org/listinfo/rust-dev > -- http://octayn.net/ _______________________________________________ Rust-dev mailing list [email protected] https://mail.mozilla.org/listinfo/rust-dev
