Acknowledge that assebly can be pulled in through static inlines

including all the necessary workarounds

See-Also: immunant/c2rust#306
See-Also: immunant/c2rust#307

Author: chrysn

Cargo.toml

@@ -18,6 +18,8 @@ default-target = "i686-unknown-linux-gnu"
 
 [dependencies]
 cty = "^0.2"
+# see https://github.com/immunant/c2rust/pull/307
+c2rust-asm-casts = { git = "https://github.com/chrysn-pull-requests/c2rust", branch = "nostd-c2rust-asm-casts" }
 
 [build-dependencies]
 bindgen = "0.53.1"

build.rs

@@ -191,6 +191,8 @@ static {type_name} init_{macro_name}(void) {{
     rustcode = rustcode.replace("    #[no_mangle]\n    fn ", "    #[no_mangle]\n    pub fn ");
     // used as a callback, therefore does need the extern "C" -- FIXME probably worth a RIOT issue
     rustcode = rustcode.replace(r"pub unsafe fn _evtimer_msg_handler", r#"pub unsafe extern "C" fn _evtimer_msg_handler"#);
+    // C2Rust still generates old-style ASM -- workaround for https://github.com/immunant/c2rust/issues/306
+    rustcode = rustcode.replace(" asm!(", " llvm_asm!(");
     // particular functions known to be const because they have macro equivalents as well
     // (Probably we could remove the 'extern "C"' from all functions)
     rustcode = rustcode.replace(r#"pub unsafe extern "C" fn mutex_init("#, r#"pub const unsafe fn mutex_init("#);

src/lib.rs

@@ -57,6 +57,8 @@
 // when experimenting with C2Rust generated extern functions, C library fn are pulled in and they
 // have stuff like `pub type iovec`
 #![feature(extern_types)]
+// eg. for irq_enable on arm
+#![feature(llvm_asm)]
 
 pub mod libc;