Some arg Fun in Rust. (0.38.1)

src/rust/Cargo.toml

@@ -6,6 +6,9 @@ edition = "2021"
 [lib]
 crate-type = ["staticlib"]
 
+[profile.dev]
+panic = "abort"
+
 [profile.release]
 panic = "abort"
 # Optimize for minimal size

src/rust/eh_personality.c

@@ -0,0 +1,2 @@
+/* Workaround for linking Rust staticlib in no_std/abort mode on some toolchains */
+void rust_eh_personality(void) {}

src/rust/src/lib.rs

@@ -11,8 +11,8 @@
 
 #![no_std]
 
-#[repr(C)]
-pub struct Vm;
+// Use an FFI-safe opaque handle for the VM pointer
+pub type Vm = core::ffi::c_void;
 
 extern "C" {
     fn vm_pop_i64(vm: *mut Vm) -> i64;
@@ -37,6 +37,23 @@ pub extern "C" fn fun_rust_get_string() -> *const core::ffi::c_char {
     b"Hello from Rust ops!\0".as_ptr() as *const _
 }
 
+// Print a C string via libc printf to stdout (acceptable under no_std via extern)
+#[no_mangle]
+pub extern "C" fn fun_rust_print_string(msg: *const core::ffi::c_char) -> i32 {
+    unsafe {
+        extern "C" {
+            fn printf(fmt: *const core::ffi::c_char, ...) -> i32;
+        }
+        let fmt = b"%s\n\0".as_ptr() as *const core::ffi::c_char;
+        printf(fmt, msg);
+    }
+    0
+}
+
+// Provide personality symbol to satisfy some linkers in no_std builds
+#[no_mangle]
+pub extern "C" fn rust_eh_personality() {}
+
 // Minimal panic handler for no_std; abort behavior requested via Cargo profile
 #[panic_handler]
 fn panic(_info: &core::panic::PanicInfo) -> ! {