Mac compatibility

psm/Cargo.toml

@@ -14,4 +14,5 @@ readme = "README.mkd"
 [dependencies]
 
 [build-dependencies]
+ar_archive_writer = "0.2.0"
 cc = "1.2.33"

psm/build.rs

@@ -111,10 +111,61 @@ fn main() {
     // directly to `ar` to assemble an archive. Otherwise we're actually
     // compiling the source assembly file.
     if asm.ends_with(".o") {
-        cfg.object(asm);
+        use ar_archive_writer::{write_archive_to_stream, NewArchiveMember, ArchiveKind};
+        use std::fs::{read, metadata};
+        use std::path::PathBuf;
+        use std::io::Cursor;
+
+        let out_dir = std::env::var("OUT_DIR").expect("OUT_DIR environment variable not set");
+        let output_path = PathBuf::from(&out_dir).join("libpsm_s.a");
+
+        let object_data = read(asm).expect("Failed to read object file");
+        let file_metadata = metadata(asm).expect("Failed to read file metadata");
+
+        // Extract file metadata
+        let mtime = file_metadata.modified().ok()
+            .and_then(|time| time.duration_since(std::time::UNIX_EPOCH).ok())
+            .map(|duration| duration.as_secs())
+            .unwrap_or(0);
+
+        #[cfg(unix)]
+        let (uid, gid, perms) = {
+            use std::os::unix::fs::MetadataExt;
+            (file_metadata.uid(), file_metadata.gid(), file_metadata.mode())
+        };
+
+        #[cfg(not(unix))]
+        let (uid, gid, perms) = (0, 0, 0o644);
+
+        let filename = asm.rsplit('/').next().unwrap_or(asm);
+        let member = NewArchiveMember {
+            buf: Box::new(object_data),
+            get_symbols: |_data: &[u8], _callback: &mut dyn FnMut(&[u8]) -> Result<(), std::io::Error>| Ok(true),
+            member_name: filename.to_string(),
+            mtime,
+            uid,
+            gid,
+            perms,
+        };
+
+        let mut output_bytes = Cursor::new(Vec::new());
+        write_archive_to_stream(
+            &mut output_bytes,
+            &[member],
+            // Unfortunately, getDefaultKind() is not available in ar_archive_writer
+            // however looking at the llvm-ar source it looks like for wasm32-any-any
+            // it falls through to Gnu https://llvm.org/doxygen/Object_2Archive_8cpp_source.html
+            ArchiveKind::Gnu,
+            false,
+        ).expect("Failed to write archive");
+
+        std::fs::write(&output_path, output_bytes.into_inner()).expect("Failed to write archive file");
+
+        println!("cargo:rustc-link-search=native={}", out_dir);
+        println!("cargo:rustc-link-lib=static=psm_s");
     } else {
         cfg.file(asm);
+        cfg.compile("libpsm_s.a");
     }
 
-    cfg.compile("libpsm_s.a");
-}
+}