BASEPRI and FAULTMASK break the standalone build on armv6m

[dtwood]

PS C:\Users\david\Devel\cortex-m> cat .\build.ps1
$env:RUSTFLAGS="-Z linker-flavor=ld.lld -C linker=ld.lld.exe"
$env:CC="clang"
$env:AR="llvm-ar"
cargo build --target=thumbv6m-none-eabi --release
PS C:\Users\david\Devel\cortex-m> .\build.ps1
   Compiling cortex-m v0.5.2 (file:///C:/Users/david/Devel/cortex-m)
error: failed to run custom build command for `cortex-m v0.5.2 (file:///C:/Users/david/Devel/cortex-m)`
process didn't exit successfully: `C:\Users\david\Devel\cortex-m\target\release\build\cortex-m-d6e8f84c8a15b15f\build-script-build` (exit code: 101)
--- stdout
TARGET = Some("thumbv6m-none-eabi")
OPT_LEVEL = Some("3")
TARGET = Some("thumbv6m-none-eabi")
HOST = Some("x86_64-pc-windows-msvc")
TARGET = Some("thumbv6m-none-eabi")
TARGET = Some("thumbv6m-none-eabi")
HOST = Some("x86_64-pc-windows-msvc")
CC_thumbv6m-none-eabi = None
CC_thumbv6m_none_eabi = None
TARGET_CC = None
CC = Some("clang")
TARGET = Some("thumbv6m-none-eabi")
HOST = Some("x86_64-pc-windows-msvc")
CFLAGS_thumbv6m-none-eabi = None
CFLAGS_thumbv6m_none_eabi = None
TARGET_CFLAGS = None
CFLAGS = None
DEBUG = Some("false")
running: "clang" "-O3" "-ffunction-sections" "-fdata-sections" "-fPIC" "--target=thumbv6m-none-eabi" "-Wall" "-Wextra" "-o" "C:\\Users\\david\\Devel\\cortex-m\\target\\thumbv6m-none-eabi\\release\\build\\cortex-m-9e47ce484a32dbc3\\out\\asm\\basepri_r.o" "-c" "asm/basepri_r.s"
cargo:warning=clang.exe: warning: argument unused during compilation: '-ffunction-sections' [-Wunused-command-line-argument]
cargo:warning=clang.exe: warning: argument unused during compilation: '-fdata-sections' [-Wunused-command-line-argument]
cargo:warning=asm/basepri_r.s:3:11: error: invalid operand for instruction
cargo:warning=  mrs r0, BASEPRI
cargo:warning=          ^
exit code: 1

--- stderr
thread 'main' panicked at '

Internal error occurred: Command "clang" "-O3" "-ffunction-sections" "-fdata-sections" "-fPIC" "--target=thumbv6m-none-eabi" "-Wall" "-Wextra" "-o" "C:\\Users\\david\\Devel\\cortex-m\\target\\thumbv6m-none-eabi\\release\\build\\cortex-m-9e47ce484a32dbc3\\out\\asm\\basepri_r.o" "-c" "asm/basepri_r.s" with args "clang" did not execute successfully (status code exit code: 1).

', C:\Users\david\.cargo\registry\src\github.com-1ecc6299db9ec823\cc-1.0.18\src\lib.rs:2181:5
note: Run with `RUST_BACKTRACE=1` for a backtrace.

[japaric]

The latest release (v0.5.3) contains a fix for this.

BTW, @dtwood I see that you are overriding the assembler / compiler and the archiver. Did the default values not work for you?

[dtwood]

I haven't actually tried the default values - my windows machine has a copy of clang/lld that I've built from source, but no gcc or binutils