replace dynamic library module with libloading

2 files changed, 18 insertions, 25 deletions

diff --git a/compiler/rustc_plugin_impl/Cargo.toml b/compiler/rustc_plugin_impl/Cargo.toml
index 4e666e7e93d..f5071eb6e8f 100644
--- a/compiler/rustc_plugin_impl/Cargo.toml
+++ b/compiler/rustc_plugin_impl/Cargo.toml
@@ -8,6 +8,7 @@ edition = "2021"
 doctest = false
 
 [dependencies]
+libloading = "0.7.1"
 rustc_middle = { path = "../rustc_middle" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_hir = { path = "../rustc_hir" }
diff --git a/compiler/rustc_plugin_impl/src/load.rs b/compiler/rustc_plugin_impl/src/load.rs
index c21075a443c..618682da4e5 100644
--- a/compiler/rustc_plugin_impl/src/load.rs
+++ b/compiler/rustc_plugin_impl/src/load.rs
@@ -1,6 +1,7 @@
 //! Used by `rustc` when loading a plugin.
 
 use crate::Registry;
+use libloading::Library;
 use rustc_ast::Crate;
 use rustc_errors::struct_span_err;
 use rustc_metadata::locator;
@@ -56,37 +57,28 @@ fn load_plugin(
     ident: Ident,
 ) {
     let lib = locator::find_plugin_registrar(sess, metadata_loader, ident.span, ident.name);
-    let fun = dylink_registrar(sess, ident.span, lib);
+    let fun = dylink_registrar(lib).unwrap_or_else(|err| {
+        // This is fatal: there are almost certainly macros we need inside this crate, so
+        // continuing would spew "macro undefined" errors.
+        sess.span_fatal(ident.span, &err.to_string());
+    });
     plugins.push(fun);
 }
 
-// Dynamically link a registrar function into the compiler process.
-fn dylink_registrar(sess: &Session, span: Span, path: PathBuf) -> PluginRegistrarFn {
-    use rustc_metadata::dynamic_lib::DynamicLibrary;
-
+/// Dynamically link a registrar function into the compiler process.
+fn dylink_registrar(lib_path: PathBuf) -> Result<PluginRegistrarFn, libloading::Error> {
     // Make sure the path contains a / or the linker will search for it.
-    let path = env::current_dir().unwrap().join(&path);
+    let lib_path = env::current_dir().unwrap().join(&lib_path);
 
-    let lib = match DynamicLibrary::open(&path) {
-        Ok(lib) => lib,
-        // this is fatal: there are almost certainly macros we need
-        // inside this crate, so continue would spew "macro undefined"
-        // errors
-        Err(err) => sess.span_fatal(span, &err),
-    };
+    let lib = unsafe { Library::new(&lib_path) }?;
 
-    unsafe {
-        let registrar = match lib.symbol("__rustc_plugin_registrar") {
-            Ok(registrar) => mem::transmute::<*mut u8, PluginRegistrarFn>(registrar),
-            // again fatal if we can't register macros
-            Err(err) => sess.span_fatal(span, &err),
-        };
+    let registrar_sym = unsafe { lib.get::<PluginRegistrarFn>(b"__rustc_plugin_registrar") }?;
 
-        // Intentionally leak the dynamic library. We can't ever unload it
-        // since the library can make things that will live arbitrarily long
-        // (e.g., an Rc cycle or a thread).
-        mem::forget(lib);
+    // Intentionally leak the dynamic library. We can't ever unload it
+    // since the library can make things that will live arbitrarily long
+    // (e.g., an Rc cycle or a thread).
+    let registrar_sym = unsafe { registrar_sym.into_raw() };
+    mem::forget(lib);
 
-        registrar
-    }
+    Ok(*registrar_sym)
 }