Platform Support

Support for different platforms ("targets") are organized into three tiers, each with a different set of guarantees. For more information on the policies for targets at each tier, see the Target Tier Policy.

Targets are identified by their "target triple" which is the string to inform the compiler what kind of output should be produced.

Component availability is tracked here.

Tier 1 with Host Tools

Tier 1 targets can be thought of as "guaranteed to work". The Rust project builds official binary releases for each tier 1 target, and automated testing ensures that each tier 1 target builds and passes tests after each change.

Tier 1 targets with host tools additionally support running tools like rustc and cargo natively on the target, and automated testing ensures that tests pass for the host tools as well. This allows the target to be used as a development platform, not just a compilation target. For the full requirements, see Tier 1 with Host Tools in the Target Tier Policy.

All tier 1 targets with host tools support the full standard library.

targetnotes
aarch64-unknown-linux-gnuARM64 Linux (kernel 4.1, glibc 2.17+)
aarch64-apple-darwinARM64 macOS (11.0+, Big Sur+)
i686-pc-windows-gnu32-bit MinGW (Windows 10+, Windows Server 2016+) 1
i686-pc-windows-msvc32-bit MSVC (Windows 10+, Windows Server 2016+) 1
i686-unknown-linux-gnu32-bit Linux (kernel 3.2+, glibc 2.17+) 1
x86_64-apple-darwin64-bit macOS (10.12+, Sierra+)
x86_64-pc-windows-gnu64-bit MinGW (Windows 10+, Windows Server 2016+)
x86_64-pc-windows-msvc64-bit MSVC (Windows 10+, Windows Server 2016+)
x86_64-unknown-linux-gnu64-bit Linux (kernel 3.2+, glibc 2.17+)
1

Due to limitations of the C ABI, floating-point support on i686 targets is non-compliant: floating-point return values are passed via an x87 register, so NaN payload bits can be lost. Functions with the default Rust ABI are not affected. See issue #115567.

Tier 1

Tier 1 targets can be thought of as "guaranteed to work". The Rust project builds official binary releases for each tier 1 target, and automated testing ensures that each tier 1 target builds and passes tests after each change. For the full requirements, see Tier 1 target policy in the Target Tier Policy.

At this time, all Tier 1 targets are Tier 1 with Host Tools.

Tier 2 with Host Tools

Tier 2 targets can be thought of as "guaranteed to build". The Rust project builds official binary releases of the standard library (or, in some cases, only the core library) for each tier 2 target, and automated builds ensure that each tier 2 target can be used as build target after each change. Automated tests are not always run so it's not guaranteed to produce a working build, but tier 2 targets often work to quite a good degree and patches are always welcome!

Tier 2 target-specific code is not closely scrutinized by Rust team(s) when modifications are made. Bugs are possible in all code, but the level of quality control for these targets is likely to be lower. See library team policy for details on the review practices for standard library code.

Tier 2 targets with host tools additionally support running tools like rustc and cargo natively on the target, and automated builds ensure that the host tools build as well. This allows the target to be used as a development platform, not just a compilation target. For the full requirements, see Tier 2 with Host Tools in the Target Tier Policy.

All tier 2 targets with host tools support the full standard library.

NOTE: The rust-docs component is not usually built for tier 2 targets, so Rustup may install the documentation for a similar tier 1 target instead.

targetnotes
aarch64-pc-windows-msvcARM64 Windows MSVC
aarch64-unknown-linux-muslARM64 Linux with musl 1.2.3
arm-unknown-linux-gnueabiArmv6 Linux (kernel 3.2, glibc 2.17)
arm-unknown-linux-gnueabihfArmv6 Linux, hardfloat (kernel 3.2, glibc 2.17)
armv7-unknown-linux-gnueabihfArmv7-A Linux, hardfloat (kernel 3.2, glibc 2.17)
loongarch64-unknown-linux-gnuLoongArch64 Linux, LP64D ABI (kernel 5.19, glibc 2.36)
loongarch64-unknown-linux-muslLoongArch64 Linux, LP64D ABI (kernel 5.19, musl 1.2.5)
powerpc-unknown-linux-gnuPowerPC Linux (kernel 3.2, glibc 2.17)
powerpc64-unknown-linux-gnuPPC64 Linux (kernel 3.2, glibc 2.17)
powerpc64le-unknown-linux-gnuPPC64LE Linux (kernel 3.10, glibc 2.17)
riscv64gc-unknown-linux-gnuRISC-V Linux (kernel 4.20, glibc 2.29)
riscv64gc-unknown-linux-muslRISC-V Linux (kernel 4.20, musl 1.2.3)
s390x-unknown-linux-gnuS390x Linux (kernel 3.2, glibc 2.17)
x86_64-unknown-freebsd64-bit FreeBSD
x86_64-unknown-illumosillumos
x86_64-unknown-linux-musl64-bit Linux with musl 1.2.3
x86_64-unknown-netbsdNetBSD/amd64

Tier 2 without Host Tools

Tier 2 targets can be thought of as "guaranteed to build". The Rust project builds official binary releases of the standard library (or, in some cases, only the core library) for each tier 2 target, and automated builds ensure that each tier 2 target can be used as build target after each change. Automated tests are not always run so it's not guaranteed to produce a working build, but tier 2 targets often work to quite a good degree and patches are always welcome! For the full requirements, see Tier 2 target policy in the Target Tier Policy.

The std column in the table below has the following meanings:

  • ✓ indicates the full standard library is available.
  • * indicates the target only supports no_std development.
  • ? indicates the standard library support is a work-in-progress.

Tier 2 target-specific code is not closely scrutinized by Rust team(s) when modifications are made. Bugs are possible in all code, but the level of quality control for these targets is likely to be lower. See library team policy for details on the review practices for standard library code.

NOTE: The rust-docs component is not usually built for tier 2 targets, so Rustup may install the documentation for a similar tier 1 target instead.

targetstdnotes
aarch64-apple-ios✓ARM64 iOS
aarch64-apple-ios-macabi✓Mac Catalyst on ARM64
aarch64-apple-ios-sim✓Apple iOS Simulator on ARM64
aarch64-unknown-fuchsia✓ARM64 Fuchsia
aarch64-linux-android✓ARM64 Android
aarch64-pc-windows-gnullvm✓ARM64 MinGW (Windows 10+), LLVM ABI
aarch64-unknown-linux-ohos✓ARM64 OpenHarmony
aarch64-unknown-none-softfloat*Bare ARM64, softfloat
aarch64-unknown-none*Bare ARM64, hardfloat
aarch64-unknown-uefi?ARM64 UEFI
arm-linux-androideabi✓Armv6 Android
arm-unknown-linux-musleabi✓Armv6 Linux with musl 1.2.3
arm-unknown-linux-musleabihf✓Armv6 Linux with musl 1.2.3, hardfloat
arm64ec-pc-windows-msvc✓Arm64EC Windows MSVC
armebv7r-none-eabi*Bare Armv7-R, Big Endian
armebv7r-none-eabihf*Bare Armv7-R, Big Endian, hardfloat
armv5te-unknown-linux-gnueabi✓Armv5TE Linux (kernel 4.4, glibc 2.23)
armv5te-unknown-linux-musleabi✓Armv5TE Linux with musl 1.2.3
armv7-linux-androideabi✓Armv7-A Android
armv7-unknown-linux-gnueabi✓Armv7-A Linux (kernel 4.15, glibc 2.27)
armv7-unknown-linux-musleabi✓Armv7-A Linux with musl 1.2.3
armv7-unknown-linux-musleabihf✓Armv7-A Linux with musl 1.2.3, hardfloat
armv7-unknown-linux-ohos✓Armv7-A OpenHarmony
armv7a-none-eabi*Bare Armv7-A
armv7r-none-eabi*Bare Armv7-R
armv7r-none-eabihf*Bare Armv7-R, hardfloat
i586-pc-windows-msvc*32-bit Windows w/o SSE 2
i586-unknown-linux-gnu✓32-bit Linux w/o SSE (kernel 3.2, glibc 2.17) 2
i586-unknown-linux-musl✓32-bit Linux w/o SSE, musl 1.2.3 2
i686-linux-android✓32-bit x86 Android 1
i686-pc-windows-gnullvm✓32-bit x86 MinGW (Windows 10+), LLVM ABI 1
i686-unknown-freebsd✓32-bit FreeBSD 1
i686-unknown-linux-musl✓32-bit Linux with musl 1.2.3 1
i686-unknown-uefi?32-bit UEFI
loongarch64-unknown-none*LoongArch64 Bare-metal (LP64D ABI)
loongarch64-unknown-none-softfloat*LoongArch64 Bare-metal (LP64S ABI)
nvptx64-nvidia-cuda*--emit=asm generates PTX code that runs on NVIDIA GPUs
riscv32imac-unknown-none-elf*Bare RISC-V (RV32IMAC ISA)
riscv32i-unknown-none-elf*Bare RISC-V (RV32I ISA)
riscv32im-unknown-none-elf*Bare RISC-V (RV32IM ISA)
riscv32imc-unknown-none-elf*Bare RISC-V (RV32IMC ISA)
riscv32imafc-unknown-none-elf*Bare RISC-V (RV32IMAFC ISA)
riscv64gc-unknown-none-elf*Bare RISC-V (RV64IMAFDC ISA)
riscv64imac-unknown-none-elf*Bare RISC-V (RV64IMAC ISA)
sparc64-unknown-linux-gnu✓SPARC Linux (kernel 4.4, glibc 2.23)
sparcv9-sun-solaris✓SPARC Solaris 11, illumos
thumbv6m-none-eabi*Bare Armv6-M
thumbv7em-none-eabi*Bare Armv7E-M
thumbv7em-none-eabihf*Bare Armv7E-M, hardfloat
thumbv7m-none-eabi*Bare Armv7-M
thumbv7neon-linux-androideabi✓Thumb2-mode Armv7-A Android with NEON
thumbv7neon-unknown-linux-gnueabihf✓Thumb2-mode Armv7-A Linux with NEON (kernel 4.4, glibc 2.23)
thumbv8m.base-none-eabi*Bare Armv8-M Baseline
thumbv8m.main-none-eabi*Bare Armv8-M Mainline
thumbv8m.main-none-eabihf*Bare Armv8-M Mainline, hardfloat
wasm32-unknown-emscripten✓WebAssembly via Emscripten
wasm32-unknown-unknown✓WebAssembly
wasm32-wasip1✓WebAssembly with WASIp1
wasm32-wasip2✓WebAssembly with WASIp2
wasm32-wasip1-threads✓WebAssembly with WASI Preview 1 and threads
wasm32v1-none*WebAssembly limited to 1.0 features and no imports
x86_64-apple-ios✓64-bit x86 iOS
x86_64-apple-ios-macabi✓Mac Catalyst on x86_64
x86_64-fortanix-unknown-sgx✓Fortanix ABI for 64-bit Intel SGX
x86_64-unknown-fuchsia✓64-bit x86 Fuchsia
x86_64-linux-android✓64-bit x86 Android
x86_64-pc-solaris✓64-bit Solaris 11, illumos
x86_64-pc-windows-gnullvm✓64-bit x86 MinGW (Windows 10+), LLVM ABI
x86_64-unknown-linux-gnux32✓64-bit Linux (x32 ABI) (kernel 4.15, glibc 2.27)
x86_64-unknown-linux-ohos✓x86_64 OpenHarmony
x86_64-unknown-none*Freestanding/bare-metal x86_64, softfloat
x86_64-unknown-redox✓Redox OS
x86_64-unknown-uefi?64-bit UEFI
2

Floating-point support on i586 targets is non-compliant: the x87 registers and instructions used for these targets do not provide IEEE-754-compliant behavior, in particular when it comes to rounding and NaN payload bits. See issue #114479.

Tier 3

Tier 3 targets are those which the Rust codebase has support for, but which the Rust project does not build or test automatically, so they may or may not work. Official builds are not available. For the full requirements, see Tier 3 target policy in the Target Tier Policy.

The std column in the table below has the following meanings:

  • ✓ indicates the full standard library is available.
  • * indicates the target only supports no_std development.
  • ? indicates the standard library support is unknown or a work-in-progress.

Tier 3 target-specific code is not closely scrutinized by Rust team(s) when modifications are made. Bugs are possible in all code, but the level of quality control for these targets is likely to be lower. See library team policy for details on the review practices for standard library code.

The host column indicates whether the codebase includes support for building host tools.

targetstdhostnotes
arm64e-apple-darwin✓✓ARM64e Apple Darwin
arm64e-apple-ios✓ARM64e Apple iOS
arm64e-apple-tvos✓ARM64e Apple tvOS
aarch64-apple-tvos✓ARM64 tvOS
aarch64-apple-tvos-sim✓ARM64 tvOS Simulator
aarch64-apple-watchos✓ARM64 Apple WatchOS
aarch64-apple-watchos-sim✓ARM64 Apple WatchOS Simulator
aarch64-apple-visionos✓ARM64 Apple visionOS
aarch64-apple-visionos-sim✓ARM64 Apple visionOS Simulator
aarch64-kmc-solid_asp3✓ARM64 SOLID with TOPPERS/ASP3
aarch64-nintendo-switch-freestanding*ARM64 Nintendo Switch, Horizon
aarch64-unknown-teeos?ARM64 TEEOS
aarch64-unknown-nto-qnx700?ARM64 QNX Neutrino 7.0 RTOS
aarch64-unknown-nto-qnx710✓ARM64 QNX Neutrino 7.1 RTOS
aarch64-unknown-freebsd✓✓ARM64 FreeBSD
aarch64-unknown-hermit✓ARM64 Hermit
aarch64-unknown-illumos✓✓ARM64 illumos
aarch64-unknown-linux-gnu_ilp32✓✓ARM64 Linux (ILP32 ABI)
aarch64-unknown-netbsd✓✓ARM64 NetBSD
aarch64-unknown-openbsd✓✓ARM64 OpenBSD
aarch64-unknown-redox✓ARM64 Redox OS
aarch64-unknown-trusty?
aarch64-uwp-windows-msvc✓
aarch64-wrs-vxworks✓ARM64 VxWorks OS
aarch64_be-unknown-linux-gnu_ilp32✓✓ARM64 Linux (big-endian, ILP32 ABI)
aarch64_be-unknown-linux-gnu✓✓ARM64 Linux (big-endian)
aarch64_be-unknown-netbsd✓✓ARM64 NetBSD (big-endian)
arm64_32-apple-watchos✓Arm Apple WatchOS 64-bit with 32-bit pointers
armeb-unknown-linux-gnueabi✓?Arm BE8 the default Arm big-endian architecture since Armv6.
armv4t-none-eabi*Bare Armv4T
armv4t-unknown-linux-gnueabi?Armv4T Linux
armv5te-none-eabi*Bare Armv5TE
armv5te-unknown-linux-uclibceabi?Armv5TE Linux with uClibc
armv6-unknown-freebsd✓✓Armv6 FreeBSD
armv6-unknown-netbsd-eabihf✓✓Armv6 NetBSD w/hard-float
armv6k-nintendo-3ds?Armv6k Nintendo 3DS, Horizon (Requires devkitARM toolchain)
armv7-rtems-eabihf?RTEMS OS for ARM BSPs
armv7-sony-vita-newlibeabihf✓Armv7-A Cortex-A9 Sony PlayStation Vita (requires VITASDK toolchain)
armv7-unknown-linux-uclibceabi✓✓Armv7-A Linux with uClibc, softfloat
armv7-unknown-linux-uclibceabihf✓?Armv7-A Linux with uClibc, hardfloat
armv7-unknown-freebsd✓✓Armv7-A FreeBSD
armv7-unknown-netbsd-eabihf✓✓Armv7-A NetBSD w/hard-float
armv7-unknown-trusty?
armv7-wrs-vxworks-eabihf✓Armv7-A for VxWorks
armv7a-kmc-solid_asp3-eabi✓ARM SOLID with TOPPERS/ASP3
armv7a-kmc-solid_asp3-eabihf✓ARM SOLID with TOPPERS/ASP3, hardfloat
armv7a-none-eabihf*Bare Armv7-A, hardfloat
armv7k-apple-watchos✓Armv7-A Apple WatchOS
armv7s-apple-ios✓Armv7-A Apple-A6 Apple iOS
armv8r-none-eabihf*Bare Armv8-R, hardfloat
avr-unknown-gnu-atmega328*AVR. Requires -Z build-std=core
bpfeb-unknown-none*BPF (big endian)
bpfel-unknown-none*BPF (little endian)
csky-unknown-linux-gnuabiv2✓C-SKY abiv2 Linux (little endian)
csky-unknown-linux-gnuabiv2hf✓C-SKY abiv2 Linux, hardfloat (little endian)
hexagon-unknown-none-elf*Bare Hexagon (v60+, HVX)
hexagon-unknown-linux-musl✓Hexagon Linux with musl 1.2.3
i386-apple-ios✓32-bit x86 iOS 1
i586-pc-nto-qnx700*32-bit x86 QNX Neutrino 7.0 RTOS 1
i586-unknown-netbsd✓32-bit x86, restricted to Pentium
i686-apple-darwin✓✓32-bit macOS (10.12+, Sierra+) 1
i686-unknown-haiku✓✓32-bit Haiku 1
i686-unknown-hurd-gnu✓✓32-bit GNU/Hurd 1
i686-unknown-netbsd✓✓NetBSD/i386 with SSE2 1
i686-unknown-openbsd✓✓32-bit OpenBSD 1
i686-unknown-redox✓i686 Redox OS
i686-uwp-windows-gnu✓1
i686-uwp-windows-msvc✓1
i686-win7-windows-msvc✓32-bit Windows 7 support 1
i686-wrs-vxworks✓1
loongarch64-unknown-linux-ohos✓LoongArch64 OpenHarmony
m68k-unknown-linux-gnu?Motorola 680x0 Linux
mips-unknown-linux-gnu✓✓MIPS Linux (kernel 4.4, glibc 2.23)
mips-unknown-linux-musl✓MIPS Linux with musl 1.2.3
mips-unknown-linux-uclibc✓MIPS Linux with uClibc
mips64-openwrt-linux-musl?MIPS64 for OpenWrt Linux musl 1.2.3
mips64-unknown-linux-gnuabi64✓✓MIPS64 Linux, N64 ABI (kernel 4.4, glibc 2.23)
mips64-unknown-linux-muslabi64✓MIPS64 Linux, N64 ABI, musl 1.2.3
mips64el-unknown-linux-gnuabi64✓✓MIPS64 (little endian) Linux, N64 ABI (kernel 4.4, glibc 2.23)
mips64el-unknown-linux-muslabi64✓MIPS64 (little endian) Linux, N64 ABI, musl 1.2.3
mipsel-unknown-linux-gnu✓✓MIPS (little endian) Linux (kernel 4.4, glibc 2.23)
mipsel-unknown-linux-musl✓MIPS (little endian) Linux with musl 1.2.3
mipsel-unknown-netbsd✓✓32-bit MIPS (LE), requires mips32 cpu support
mipsel-sony-psp*MIPS (LE) Sony PlayStation Portable (PSP)
mipsel-sony-psx*MIPS (LE) Sony PlayStation 1 (PSX)
mipsel-unknown-linux-uclibc✓MIPS (LE) Linux with uClibc
mipsel-unknown-none*Bare MIPS (LE) softfloat
mipsisa32r6-unknown-linux-gnu?32-bit MIPS Release 6 Big Endian
mipsisa32r6el-unknown-linux-gnu?32-bit MIPS Release 6 Little Endian
mipsisa64r6-unknown-linux-gnuabi64?64-bit MIPS Release 6 Big Endian
mipsisa64r6el-unknown-linux-gnuabi64✓✓64-bit MIPS Release 6 Little Endian
msp430-none-elf*16-bit MSP430 microcontrollers
powerpc-unknown-linux-gnuspe✓PowerPC SPE Linux
powerpc-unknown-linux-musl?PowerPC Linux with musl 1.2.3
powerpc-unknown-linux-muslspe?PowerPC SPE Linux
powerpc-unknown-netbsd✓✓NetBSD 32-bit powerpc systems
powerpc-unknown-openbsd*
powerpc-wrs-vxworks-spe✓
powerpc-wrs-vxworks✓
powerpc64-unknown-freebsd✓✓PPC64 FreeBSD (ELFv1 and ELFv2)
powerpc64le-unknown-freebsd✓✓PPC64LE FreeBSD
powerpc-unknown-freebsd?PowerPC FreeBSD
powerpc64-unknown-linux-musl?64-bit PowerPC Linux with musl 1.2.3
powerpc64-wrs-vxworks✓
powerpc64le-unknown-linux-musl?64-bit PowerPC Linux with musl 1.2.3, Little Endian
powerpc64-unknown-openbsd✓✓OpenBSD/powerpc64
powerpc64-ibm-aix?64-bit AIX (7.2 and newer)
riscv32gc-unknown-linux-gnu✓RISC-V Linux (kernel 5.4, glibc 2.33)
riscv32gc-unknown-linux-musl?RISC-V Linux (kernel 5.4, musl 1.2.3 + RISCV32 support patches)
riscv32im-risc0-zkvm-elf?RISC Zero's zero-knowledge Virtual Machine (RV32IM ISA)
riscv32ima-unknown-none-elf*Bare RISC-V (RV32IMA ISA)
riscv32imac-unknown-xous-elf?RISC-V Xous (RV32IMAC ISA)
riscv32imc-esp-espidf✓RISC-V ESP-IDF
riscv32imac-esp-espidf✓RISC-V ESP-IDF
riscv32imafc-esp-espidf✓RISC-V ESP-IDF
riscv32-wrs-vxworks✓
riscv64gc-unknown-hermit✓RISC-V Hermit
riscv64gc-unknown-freebsd?RISC-V FreeBSD
riscv64gc-unknown-fuchsia?RISC-V Fuchsia
riscv64gc-unknown-netbsd✓✓RISC-V NetBSD
riscv64gc-unknown-openbsd✓✓OpenBSD/riscv64
riscv64-linux-android?RISC-V 64-bit Android
riscv64-wrs-vxworks✓
s390x-unknown-linux-musl✓S390x Linux (kernel 3.2, musl 1.2.3)
sparc-unknown-linux-gnu✓32-bit SPARC Linux
sparc-unknown-none-elf*Bare 32-bit SPARC V7+
sparc64-unknown-netbsd✓✓NetBSD/sparc64
sparc64-unknown-openbsd✓✓OpenBSD/sparc64
thumbv4t-none-eabi*Thumb-mode Bare Armv4T
thumbv5te-none-eabi*Thumb-mode Bare Armv5TE
thumbv7a-pc-windows-msvc✓
thumbv7a-uwp-windows-msvc✓
thumbv7neon-unknown-linux-musleabihf?Thumb2-mode Armv7-A Linux with NEON, musl 1.2.3
wasm64-unknown-unknown?WebAssembly
x86_64-apple-tvos✓x86 64-bit tvOS
x86_64-apple-watchos-sim✓x86 64-bit Apple WatchOS simulator
x86_64-pc-nto-qnx710✓x86 64-bit QNX Neutrino 7.1 RTOS
x86_64-unikraft-linux-musl✓64-bit Unikraft with musl 1.2.3
x86_64-unknown-dragonfly✓✓64-bit DragonFlyBSD
x86_64-unknown-haiku✓✓64-bit Haiku
x86_64-unknown-hurd-gnu✓✓64-bit GNU/Hurd
x86_64-unknown-hermit✓x86_64 Hermit
x86_64-unknown-l4re-uclibc?
x86_64-unknown-openbsd✓✓64-bit OpenBSD
x86_64-unknown-trusty?
x86_64-uwp-windows-gnu✓
x86_64-uwp-windows-msvc✓
x86_64-win7-windows-msvc✓64-bit Windows 7 support
x86_64-wrs-vxworks✓
x86_64h-apple-darwin✓✓macOS with late-gen Intel (at least Haswell)
x86_64-unknown-linux-none*64-bit Linux with no libc
xtensa-esp32-none-elf*Xtensa ESP32
xtensa-esp32-espidf✓Xtensa ESP32
xtensa-esp32s2-none-elf*Xtensa ESP32-S2
xtensa-esp32s2-espidf✓Xtensa ESP32-S2
xtensa-esp32s3-none-elf*Xtensa ESP32-S3
xtensa-esp32s3-espidf✓Xtensa ESP32-S3
thumbv6m-nuttx-eabi*ARMv6M with NuttX
thumbv7m-nuttx-eabi*ARMv7M with NuttX
thumbv7em-nuttx-eabi*ARMv7EM with NuttX
thumbv7em-nuttx-eabihf*ARMv7EM with NuttX, hardfloat
thumbv8m.base-nuttx-eabi*ARMv8M Baseline with NuttX
thumbv8m.main-nuttx-eabi*ARMv8M Mainline with NuttX
thumbv8m.main-nuttx-eabihf*ARMv8M Mainline with NuttX, hardfloat
riscv32imc-unknown-nuttx-elf*RISC-V 32bit with NuttX
riscv32imac-unknown-nuttx-elf*RISC-V 32bit with NuttX
riscv32imafc-unknown-nuttx-elf*RISC-V 32bit with NuttX
riscv64imac-unknown-nuttx-elf*RISC-V 64bit with NuttX
riscv64gc-unknown-nuttx-elf*RISC-V 64bit with NuttX
riscv32e-unknown-none-elf*Bare RISC-V (RV32E ISA)
riscv32em-unknown-none-elf*Bare RISC-V (RV32EM ISA)
riscv32emc-unknown-none-elf*Bare RISC-V (RV32EMC ISA)