tools/[Rust|D]: Fix the Rust and D Builds for QEMU RISC-V

[lupyuen]

Summary

This PR fixes the build for Rust Apps on QEMU RISC-V 64-bit. Previously the Rust Build selected the incorrect Rust Target riscv64i-unknown-none-elf. Now the Rust Build selects the correct Rust Target: riscv64gc-unknown-none-elf.

To validate the fix, we create a new NuttX Config rv-virt:leds64_rust that builds the leds_rust example for QEMU RISC-V 64-bit. leds_rust will be compiled for every run of NuttX CI.

Note that Rust Apps won't build correctly for QEMU RISC-V 32-bit. This requires a Rust Custom Target for riscv32gc, which will make the NuttX Makefiles much more complicated.

This PR also fixes the 32-bit RISC-V Target for D Apps. D Targets ("riscv32") are named differently from Rust Targets ("riscv32gc"), this PR restores the correct Target Names.

Modified Files

tools/Rust.defs: Rename the RISC-V ISA imafdc to gc for Rust Targets

tools/D.defs: Exclude the RISC-V ISA for D Targets

tools/ci/platforms/ubuntu.sh: Add Rust Target riscv64gc-unknown-none-elf for CI

New Files

boards/risc-v/qemu-rv/rv-virt/configs/leds64_rust/defconfig: Add new NuttX Config rv-virt:leds64_rust

Updated Docs

applications/examples/leds_rust/index.rst: Add leds_rust example app

platforms/risc-v/qemu-rv/boards/rv-virt/index.rst: Add rv-virt:leds64_rust config

Impact

Previously, Rust and D Apps failed to build for QEMU RISC-V due to the incorrect target. With this PR, they will build correctly. There is no impact on C Apps.

Testing

For Rust Apps: We tested the leds_rust example app on rv-virt:leds64_rust (QEMU RISC-V 64-bit): Test Log

$ tools/configure.sh rv-virt:leds64_rust
...
NuttShell (NSH) NuttX-12.4.0
nsh> uname -a
NuttX 12.4.0 723281ed9b Aug  6 2024 15:37:10 risc-v rv-virt

nsh> leds_rust
Hello, Rust!!
Opening /dev/userleds
Set LED 1 to 1
board_userled: LED 1 set to 1
board_userled: LED 2 set to 0
board_userled: LED 3 set to 0
Sleeping...
Set LED 1 to 0
board_userled: LED 1 set to 0
board_userled: LED 2 set to 0
board_userled: LED 3 set to 0

Note that leds_rust won't build correctly for 32-bit rv-virt:leds. To date, NuttX has never supported Rust Apps for QEMU RISC-V 32-bit, because the Rust Custom Target for riscv32gc is missing: Build Log

$ tools/configure.sh rv-virt:leds
$ kconfig-tweak --enable CONFIG_EXAMPLES_LEDS_RUST
$ make olddefconfig
$ make
error: Error loading target specification:
Could not find specification for target "riscv32gc-unknown-none-elf"

For D Apps: We tested the hello_d example app on rv-virt:nsh (QEMU RISC-V 32-bit): Test Log

$ tools/configure.sh rv-virt:nsh
$ kconfig-tweak --enable CONFIG_EXAMPLES_HELLO_D
$ make olddefconfig
...
NuttShell (NSH) NuttX-12.4.0
nsh> uname -a
NuttX 12.4.0 723281ed9b Aug  6 2024 15:33:01 risc-v rv-virt

nsh> hello_d
Hello World, [generic-rv32]!
hello_d_main: Saying hello from the dynamically constructed instance
DHelloWorld.HelloWorld: CONSTRUCTION FAILED!
hello_d_main: Saying hello from the instance constructed on the stack
DHelloWorld.HelloWorld: Hello, World!!

Note that hello_d won't build correctly for 64-bit rv-virt:nsh64. To date, NuttX has never supported 64-bit RISC-V for D Apps: Build Log

$ tools/configure.sh rv-virt:nsh64
$ kconfig-tweak --enable CONFIG_EXAMPLES_HELLO_D
$ make olddefconfig
$ make
nuttx/staging/libapps.a(hello_d_main.d.apps.examples.hello_d_1.o): in function `DHelloWorld::HelloWorld()':
apps/examples/hello_d/hello_d_main.d:67:(.text._ZN11DHelloWorld10HelloWorldEv+0x14): relocation truncated to fit: R_RISCV_HI20 against `.L.str'
nuttx/staging/libapps.a(hello_d_main.d.apps.examples.hello_d_1.o): in function `hello_d_main':
apps/examples/hello_d/hello_d_main.d:106:(.text.hello_d_main+0x14): relocation truncated to fit: R_RISCV_HI20 against `.L.str.2'