Dlopen libgccjit.so in order to support multiple targets more easily

Author: antoyo

Cargo.lock

@@ -56,18 +56,18 @@ dependencies = [
 
 [[package]]
 name = "gccjit"
-version = "2.10.0"
+version = "3.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60362e038e71e4bdc1a5b23fb45e1aba587b5947fe0db58f4871d95608f89eca"
+checksum = "9a1d137657dee9b660e884dc11d41efbff8201aa49f9f75f7bc7d400ad1e9062"
 dependencies = [
  "gccjit_sys",
 ]
 
 [[package]]
 name = "gccjit_sys"
-version = "0.9.0"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ddd542c8414e122217551c6af6b7d33acf51a227aee85276f218c087525e01bb"
+checksum = "dde7e9f1ec00279a8e901f30567f97ab7536b544b70cc1f79833f35caeed877a"
 dependencies = [
  "libc",
 ]

Cargo.toml

@@ -24,11 +24,11 @@ default = ["master"]
 [dependencies]
 object = { version = "0.37.0", default-features = false, features = ["std", "read"] }
 tempfile = "3.20"
-gccjit = "2.10"
-#gccjit = { git = "https://github.com/rust-lang/gccjit.rs" }
+gccjit = { version = "3.1", features = ["dlopen"] }
+#gccjit = { git = "https://github.com/rust-lang/gccjit.rs", branch = "error-dlopen", features = ["dlopen"] }
 
 # Local copy.
-#gccjit = { path = "../gccjit.rs" }
+#gccjit = { path = "../gccjit.rs", features = ["dlopen"] }
 
 [dev-dependencies]
 boml = "0.3.1"

libgccjit.version

@@ -1 +1 @@
-28b84db392ac0a572f1a2a2a1317aa5f2bc742cb
+0081ca6631abdfa02bf42bc85aaf507b8a0e6beb

src/lib.rs

@@ -69,6 +69,7 @@ mod type_;
 mod type_of;
 
 use std::any::Any;
+use std::ffi::CString;
 use std::fmt::Debug;
 use std::ops::Deref;
 use std::path::PathBuf;
@@ -142,7 +143,7 @@ impl TargetInfo {
 
 #[derive(Clone)]
 pub struct LockedTargetInfo {
-    info: Arc<Mutex<IntoDynSyncSend<TargetInfo>>>,
+    info: Arc<Mutex<IntoDynSyncSend<Option<TargetInfo>>>>,
 }
 
 impl Debug for LockedTargetInfo {
@@ -153,11 +154,21 @@ impl Debug for LockedTargetInfo {
 
 impl LockedTargetInfo {
     fn cpu_supports(&self, feature: &str) -> bool {
-        self.info.lock().expect("lock").cpu_supports(feature)
+        self.info
+            .lock()
+            .expect("lock")
+            .as_ref()
+            .expect("target info not initialized")
+            .cpu_supports(feature)
     }
 
     fn supports_target_dependent_type(&self, typ: CType) -> bool {
-        self.info.lock().expect("lock").supports_target_dependent_type(typ)
+        self.info
+            .lock()
+            .expect("lock")
+            .as_ref()
+            .expect("target info not initialized")
+            .supports_target_dependent_type(typ)
     }
 }
 
@@ -169,6 +180,19 @@ pub struct GccCodegenBackend {
 
 static LTO_SUPPORTED: AtomicBool = AtomicBool::new(false);
 
+fn load_libgccjit_if_needed() {
+    if gccjit::is_loaded() {
+        // Do not load a libgccjit second time.
+        return;
+    }
+
+    let string = CString::new("libgccjit.so").expect("string to libgccjit path");
+
+    if let Err(error) = gccjit::load(&string) {
+        panic!("Cannot load libgccjit.so: {}", error);
+    }
+}
+
 impl CodegenBackend for GccCodegenBackend {
     fn locale_resource(&self) -> &'static str {
         crate::DEFAULT_LOCALE_RESOURCE
@@ -179,6 +203,8 @@ impl CodegenBackend for GccCodegenBackend {
     }
 
     fn init(&self, _sess: &Session) {
+        load_libgccjit_if_needed();
+
         #[cfg(feature = "master")]
         {
             let target_cpu = target_cpu(_sess);
@@ -189,7 +215,8 @@ impl CodegenBackend for GccCodegenBackend {
                 context.add_command_line_option(format!("-march={}", target_cpu));
             }
 
-            **self.target_info.info.lock().expect("lock") = context.get_target_info();
+            *self.target_info.info.lock().expect("lock") =
+                IntoDynSyncSend(Some(context.get_target_info()));
         }
 
         #[cfg(feature = "master")]
@@ -217,6 +244,9 @@ impl CodegenBackend for GccCodegenBackend {
                 .info
                 .lock()
                 .expect("lock")
+                .0
+                .as_ref()
+                .expect("target info not initialized")
                 .supports_128bit_integers
                 .store(check_context.get_last_error() == Ok(None), Ordering::SeqCst);
         }
@@ -438,13 +468,12 @@ pub fn __rustc_codegen_backend() -> Box<dyn CodegenBackend> {
     let info = {
         // Check whether the target supports 128-bit integers, and sized floating point types (like
         // Float16).
-        let context = Context::default();
-        Arc::new(Mutex::new(IntoDynSyncSend(context.get_target_info())))
+        Arc::new(Mutex::new(IntoDynSyncSend(None)))
     };
     #[cfg(not(feature = "master"))]
-    let info = Arc::new(Mutex::new(IntoDynSyncSend(TargetInfo {
+    let info = Arc::new(Mutex::new(IntoDynSyncSend(Some(TargetInfo {
         supports_128bit_integers: AtomicBool::new(false),
-    })));
+    }))));
 
     Box::new(GccCodegenBackend {
         lto_supported: Arc::new(AtomicBool::new(false)),