[rust][tools] Fix Rust build example configuration handling

Improve the Rust build integration across core, applications, components, and module examples. Fix build failure propagation, target and feature handling, linker flags, example configuration semantics, and add STM32 CI attach coverage.

Author: yanhu7150-tech

bsp/stm32/stm32f407-rt-spark/.ci/attachconfig/ci.attachconfig.yml

@@ -246,6 +246,26 @@ component.cherryusb_cdc:
       - CONFIG_RT_CHERRYUSB_DEVICE_DWC2_ST=y
       - CONFIG_RT_CHERRYUSB_DEVICE_CDC_ACM=y
       - CONFIG_RT_CHERRYUSB_DEVICE_TEMPLATE_CDC_ACM=y
+# ------ rust CI ------
+rust:
+    <<: *scons
+    pre_build: |
+      python3 -m pip install --user toml
+      curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain nightly --profile minimal
+      sudo ln -sf "$HOME/.cargo/bin/cargo" /usr/local/bin/cargo
+      sudo ln -sf "$HOME/.cargo/bin/rustc" /usr/local/bin/rustc
+      sudo ln -sf "$HOME/.cargo/bin/rustup" /usr/local/bin/rustup
+      rustup target add thumbv7em-none-eabihf
+      rustup component add rust-src
+      rustc --version
+      cargo --version
+    kconfig:
+      - CONFIG_RT_USING_RUST=y
+      - CONFIG_RT_RUST_CORE=y
+      - CONFIG_RT_USING_RUST_EXAMPLES=y
+      - CONFIG_RT_RUST_BUILD_APPLICATIONS=y
+      - CONFIG_RT_RUST_BUILD_COMPONENTS=y
+      - CONFIG_RUST_LOG_COMPONENT=y
 
 devices.soft_i2c:
   <<: *scons

components/rust/README.md

@@ -84,6 +84,14 @@ rustup target add thumbv7em-none-eabi
 # Add other targets that match your toolchain/ABI as needed
 ```
 
+For ARM targets whose C toolchain uses `-fshort-wchar`, RT-Thread uses the nightly-only `build-std` feature to rebuild Rust `core` and `alloc` from source, keeping the Rust ARM EABI wchar size aligned with the C toolchain. Install `rust-src` and the corresponding target for the same nightly toolchain. From the RT-Thread repository root, set a directory-local nightly override so that the plain `cargo` and `rustc` commands invoked by SCons use this toolchain throughout the repository:
+
+```bash
+rustup toolchain install nightly --profile minimal --component rust-src
+rustup target add --toolchain nightly <target-name>
+rustup override set nightly
+```
+
 ### Build
 
 ```bash

components/rust/README_zh.md

@@ -84,6 +84,14 @@ rustup target add thumbv7em-none-eabi
 # 其他目标请根据实际工具链/ABI 添加对应的 Rust target
 ```
 
+对于 C 工具链使用 `-fshort-wchar` 的 ARM 目标，RT-Thread 会使用仅 nightly 支持的 `build-std` 从源码重新构建 Rust `core` 和 `alloc`，使 Rust ARM EABI wchar 大小与 C 工具链保持一致。请为同一个 nightly 工具链安装 `rust-src` 和对应 target，并在 RT-Thread 仓库根目录设置目录级 nightly override，使 SCons 在整个仓库目录树中调用的普通 `cargo` 和 `rustc` 命令使用该工具链：
+
+```bash
+rustup toolchain install nightly --profile minimal --component rust-src
+rustup target add --toolchain nightly <target-name>
+rustup override set nightly
+```
+
 ### 构建
 
 ```bash

components/rust/SConscript

@@ -10,7 +10,7 @@ def _has(sym: str) -> bool:
     except Exception:
         return bool(GetDepend(sym))
 
-if not _has('RT_USING_RUST'):
+if not _has('RT_USING_RUST') and not GetOption('clean'):
     Return('objs')
 
 cwd = GetCurrentDir()

components/rust/core/Cargo.toml

@@ -10,6 +10,17 @@ crate-type = ["rlib", "staticlib"]
 [features]
 default = []
 smp = []
+fs = []
+libdl = []
+
+[package.metadata.rt-thread.features.smp]
+all = ["RT_USING_SMP"]
+
+[package.metadata.rt-thread.features.fs]
+all = ["RT_USING_DFS", "DFS_USING_POSIX"]
+
+[package.metadata.rt-thread.features.libdl]
+all = ["RT_USING_MODULE"]
 
 [profile.dev]
 panic = "abort"

components/rust/core/SConscript

@@ -1,16 +1,20 @@
 import os
+import sys
 from building import *
+from SCons.Subst import quote_spaces
 
 cwd = GetCurrentDir()
 
 sys.path.append(os.path.join(cwd, '../tools'))
 from build_support import (
     detect_rust_target,
     make_rustflags,
+    make_cargo_build_std_args,
     collect_features,
     verify_rust_toolchain,
     ensure_rust_target_installed,
     cargo_build_staticlib,
+    get_staticlib_link_name,
     clean_rust_build,
 )
 def _has(sym: str) -> bool:
@@ -20,10 +24,28 @@ def _has(sym: str) -> bool:
         return bool(GetDepend(sym))
 
 
-# Source files – MSH command glue
-src = ['rust_cmd.c']
+group = []
+if not _has('RT_RUST_CORE') and not GetOption('clean'):
+    Return('group')
+
+
+def get_staticlib_link_name_from_artifact(lib_path):
+    """Derive the link name from the actual staticlib artifact file name."""
+    artifact_name = os.path.basename(os.fspath(lib_path))
+    if artifact_name.startswith("lib") and artifact_name.endswith(".a"):
+        return artifact_name[3:-2]
+    return None
+
+
+# Source files – MSH command glue.
+# rust_cmd.c references rust_init(), which is only provided by the Rust core
+# static library. It must only enter the build when that library is actually
+# produced; otherwise the C link stage fails with 'undefined reference to
+# rust_init' instead of failing/skipping cleanly at the Rust build step.
 LIBS = []
 LIBPATH = []
+LINKFLAGS = ""
+include_rust_cmd = False
 
 if GetOption('clean'):
     # Register Rust artifacts for cleaning
@@ -33,39 +55,65 @@ if GetOption('clean'):
         Clean('.', rust_build_dir)
     else:
         print('No rust build artifacts to clean')
+    # Keep rust_cmd.c in the group during clean so its object is cleaned too.
+    include_rust_cmd = True
 else:
     if verify_rust_toolchain():
         import rtconfig
+        rust_build_dir = clean_rust_build(Dir('#').abspath)
 
         target = detect_rust_target(_has, rtconfig)
         if not target:
             print('Error: Unable to detect Rust target; please check configuration')
+            sys.exit(1)
         else:
             print(f'Detected Rust target: {target}')
 
             # Optional hint if target missing
-            ensure_rust_target_installed(target)
-
-            # Build mode and features
-            debug = bool(_has('RUST_DEBUG_BUILD'))
-            features = collect_features(_has)
+            if not ensure_rust_target_installed(target):
+                print('Error: Rust target is not installed; Rust library build failed')
+                sys.exit(1)
+            else:
+                # Build mode and features
+                debug = bool(_has('RUST_DEBUG_BUILD'))
+                features = collect_features(_has)
 
-            rustflags = make_rustflags(rtconfig, target)
-            rust_lib = cargo_build_staticlib(
-                rust_dir=cwd, target=target, features=features, debug=debug, rustflags=rustflags
-            )
+                rustflags = make_rustflags(rtconfig, target)
+                cargo_extra_args = make_cargo_build_std_args(rtconfig, target)
+                rust_lib = cargo_build_staticlib(
+                    rust_dir=cwd, target=target, features=features, debug=debug, rustflags=rustflags, build_root=rust_build_dir, cargo_extra_args=cargo_extra_args
+                )
 
-            if rust_lib:
-                LIBS = ['rt_rust']
-                LIBPATH = [os.path.dirname(rust_lib)]
-                print('Rust library linked successfully')
-            else:
-                print('Warning: Failed to build Rust library')
+                if rust_lib:
+                    # Derive the link name from the actual artifact so it always
+                    # matches the file that was built. Only fall back to
+                    # re-parsing Cargo.toml when the artifact name does not
+                    # follow the lib<name>.a convention.
+                    link_lib_name = get_staticlib_link_name_from_artifact(rust_lib)
+                    if not link_lib_name:
+                        link_lib_name = get_staticlib_link_name(cwd)
+                    LIBS = [link_lib_name]
+                    LIBPATH = [os.path.dirname(rust_lib)]
+                    if rtconfig.PLATFORM == 'armclang':
+                        if not (os.path.isfile(rust_lib) and os.path.getsize(rust_lib) > 0):
+                            print(f'Error: ArmClang Rust core link requires a non-empty archive, but got: {rust_lib}')
+                            sys.exit(1)
+                        LINKFLAGS = " " + quote_spaces(os.fspath(rust_lib))
+                        LIBS = []
+                        LIBPATH = []
+                    include_rust_cmd = True
+                    print('Rust library linked successfully')
+                else:
+                    print('Error: Failed to build Rust library')
+                    sys.exit(1)
     else:
-        print('Warning: Rust toolchain not found')
+        print('Error: Rust toolchain not found')
         print('Please install Rust from https://rustup.rs')
+        sys.exit(1)
 
-# Define component group for SCons
-group = DefineGroup('rust', src, depend=['RT_USING_RUST'], LIBS=LIBS, LIBPATH=LIBPATH)
+# Only define the component group (with rust_cmd.c) when the Rust core static
+# library was actually produced, so its rust_init() reference always resolves.
+if include_rust_cmd:
+    group = DefineGroup('rust', ['rust_cmd.c'], depend=['RT_USING_RUST', 'RT_RUST_CORE'], LIBS=LIBS, LIBPATH=LIBPATH, LINKFLAGS=LINKFLAGS)
 
 Return('group')

components/rust/core/src/api/mod.rs

@@ -14,6 +14,7 @@ pub mod thread;
 pub mod mutex;
 pub mod sem;
 pub mod queue;
+#[cfg(feature = "libdl")]
 pub mod libloading;
 
 
@@ -24,4 +25,5 @@ pub use thread::*;
 pub use mutex::*;
 pub use sem::*;
 pub use queue::*;
+#[cfg(feature = "libdl")]
 pub use libloading::*;

components/rust/core/src/api/queue.rs

@@ -20,7 +20,7 @@ pub type APIRawQueue = rt_mq_t;
 pub(crate) fn queue_create(name: &str, len: u64, message_size: u64) -> Option<APIRawQueue> {
     let s = CString::new(name).unwrap();
     let raw;
-    unsafe { raw = rt_mq_create(s.as_ptr(), message_size, len, 0) }
+    unsafe { raw = rt_mq_create(s.as_ptr(), message_size as rt_size_t, len as rt_size_t, 0) }
     if raw == ptr::null_mut() {
         None
     } else {
@@ -35,7 +35,7 @@ pub(crate) fn queue_send_wait(
     msg_size: u64,
     tick: i32,
 ) -> RttCResult {
-    unsafe { rt_mq_send_wait(handle, msg, msg_size, tick).into() }
+    unsafe { rt_mq_send_wait(handle, msg, msg_size as rt_size_t, tick).into() }
 }
 
 #[inline]
@@ -45,7 +45,12 @@ pub(crate) fn queue_receive_wait(
     msg_size: u64,
     tick: i32,
 ) -> RttCResult {
-    unsafe { rt_mq_recv(handle, msg, msg_size, tick).into() }
+    let ret = unsafe { rt_mq_recv(handle, msg, msg_size as rt_size_t, tick) };
+    if ret >= 0 {
+        RttCResult::Ok
+    } else {
+        ret.into()
+    }
 }
 
 #[inline]

components/rust/core/src/bindings/librt.rs

@@ -26,6 +26,7 @@ pub type rt_int32_t = c_int;
 pub type rt_uint8_t  = c_uchar;
 pub type rt_tick_t = rt_uint32_t;
 pub type rt_size_t = rt_ubase_t;
+pub type rt_ssize_t = rt_base_t;
 
 pub type rt_thread_t = *mut c_void;
 pub type rt_sem_t = *mut c_void;
@@ -94,7 +95,7 @@ unsafe extern "C" {
     pub fn rt_mq_create(name: *const c_char, msg_size: rt_size_t, max_msgs: rt_size_t, flag: rt_uint8_t) -> rt_mq_t;
     pub fn rt_mq_send(mq: rt_mq_t, buffer: *const c_void, size: rt_size_t) -> rt_err_t;
     pub fn rt_mq_send_wait(mq: rt_mq_t, buffer: *const c_void, size: rt_size_t, timeout: rt_int32_t) -> rt_err_t;
-    pub fn rt_mq_recv(mq: rt_mq_t, buffer: *mut c_void, size: rt_size_t, timeout: rt_int32_t) -> rt_base_t;
+    pub fn rt_mq_recv(mq: rt_mq_t, buffer: *mut c_void, size: rt_size_t, timeout: rt_int32_t) -> rt_ssize_t;
     pub fn rt_mq_delete(mq: rt_mq_t) -> rt_err_t;
     pub fn rt_mq_detach(mq: rt_mq_t) -> rt_err_t;
 }

components/rust/core/src/bindings/mod.rs

@@ -46,8 +46,7 @@ pub use librt::{
 
 /* Memory management functions */
 pub use librt::{
-    rt_malloc, rt_free, rt_realloc, rt_calloc, rt_malloc_align, rt_free_align,
-    rt_safe_malloc, rt_safe_free
+    rt_malloc, rt_free, rt_realloc, rt_calloc, rt_malloc_align, rt_free_align
 };
 
 /* Device management functions */