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 <farcal...@gmail.com>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 <a...@crichton.co> 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 <farcal...@gmail.com> >> 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 >> > Rustemail@example.com >> > 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 Rustfirstname.lastname@example.org https://mail.mozilla.org/listinfo/rust-dev