Allow non-LTO mode

Author: bjorn3

src/driver/lto.rs

@@ -209,6 +209,8 @@ pub(crate) fn run_aot(
     metadata: EncodedMetadata,
     need_metadata_module: bool,
 ) -> Box<OngoingCodegen> {
+    tcx.dcx().note(format!("Using LTO for {}", tcx.crate_name(LOCAL_CRATE)));
+
     // FIXME handle `-Ctarget-cpu=native`
     let target_cpu = match tcx.sess.opts.cg.target_cpu {
         Some(ref name) => name,

src/lib.rs

@@ -163,16 +163,7 @@ impl CodegenBackend for CraneliftCodegenBackend {
     }
 
     fn init(&self, sess: &Session) {
-        use rustc_session::config::{InstrumentCoverage, Lto};
-        match sess.lto() {
-            Lto::No | Lto::ThinLocal => {
-                if sess.opts.crate_name.as_deref() != Some("___") {
-                    sess.dcx().fatal("No LTO");
-                }
-            }
-            Lto::Thin | Lto::Fat => {}
-        }
-
+        use rustc_session::config::InstrumentCoverage;
         if sess.opts.cg.instrument_coverage() != InstrumentCoverage::No {
             sess.dcx()
                 .fatal("`-Cinstrument-coverage` is LLVM specific and not supported by Cranelift");
@@ -216,27 +207,23 @@ impl CodegenBackend for CraneliftCodegenBackend {
                 .unwrap_or_else(|err| tcx.sess.dcx().fatal(err))
         });
         match config.codegen_mode {
-            CodegenMode::Aot => {
-                match tcx.sess.lto() {
-                    Lto::No | Lto::ThinLocal => {
-                        driver::aot::run_aot(tcx, metadata, need_metadata_module)
-                    }
-                    Lto::Thin | Lto::Fat => {
-                        if tcx.crate_name(LOCAL_CRATE).as_str() == "compiler_builtins" {
-                            // FIXME remove special case once inline asm is supported in LTO mode
-                            driver::aot::run_aot(tcx, metadata, need_metadata_module)
-                        } else {
-                            #[cfg(feature = "lto")]
-                            return driver::lto::run_aot(tcx, metadata, need_metadata_module);
-
-                            #[cfg(not(feature = "lto"))]
-                            tcx.dcx().fatal(
-                                "LTO support was disabled when compiling rustc_codegen_cranelift",
-                            );
-                        }
+            CodegenMode::Aot => match tcx.sess.lto() {
+                Lto::No | Lto::ThinLocal => {
+                    driver::aot::run_aot(tcx, metadata, need_metadata_module)
+                }
+                Lto::Thin | Lto::Fat => {
+                    if tcx.crate_name(LOCAL_CRATE) == sym::compiler_builtins {
+                        return driver::aot::run_aot(tcx, metadata, need_metadata_module);
                     }
+
+                    #[cfg(feature = "lto")]
+                    return driver::lto::run_aot(tcx, metadata, need_metadata_module);
+
+                    #[cfg(not(feature = "lto"))]
+                    tcx.dcx()
+                        .fatal("LTO support was disabled when compiling rustc_codegen_cranelift");
                 }
-            }
+            },
             CodegenMode::Jit | CodegenMode::JitLazy => {
                 #[cfg(feature = "jit")]
                 driver::jit::run_jit(tcx, config.codegen_mode, config.jit_args);