Allow printing the version of the default codegen backend if it isn't llvm

Author: bjorn3

compiler/rustc_codegen_cranelift/src/lib.rs

@@ -167,6 +167,10 @@ impl CodegenBackend for CraneliftCodegenBackend {
         vec![]
     }
 
+    fn print_version(&self) {
+        println!("Cranelift version: {}", cranelift_codegen::VERSION);
+    }
+
     fn codegen_crate(
         &self,
         tcx: TyCtxt<'_>,

compiler/rustc_driver/src/lib.rs

@@ -21,7 +21,7 @@ use rustc_data_structures::sync::SeqCst;
 use rustc_errors::registry::{InvalidErrorCode, Registry};
 use rustc_errors::{ErrorReported, PResult};
 use rustc_feature::find_gated_cfg;
-use rustc_interface::util::{self, collect_crate_types, get_builtin_codegen_backend};
+use rustc_interface::util::{self, collect_crate_types, get_codegen_backend};
 use rustc_interface::{interface, Queries};
 use rustc_lint::LintStore;
 use rustc_metadata::locator;
@@ -765,9 +765,7 @@ pub fn version(binary: &str, matches: &getopts::Matches) {
         println!("commit-date: {}", unw(util::commit_date_str()));
         println!("host: {}", config::host_triple());
         println!("release: {}", unw(util::release_str()));
-        if cfg!(feature = "llvm") {
-            get_builtin_codegen_backend(&None, "llvm")().print_version();
-        }
+        get_codegen_backend(&None, None).print_version();
     }
 }
 
@@ -1060,9 +1058,7 @@ pub fn handle_options(args: &[String]) -> Option<getopts::Matches> {
     }
 
     if cg_flags.iter().any(|x| *x == "passes=list") {
-        if cfg!(feature = "llvm") {
-            get_builtin_codegen_backend(&None, "llvm")().print_passes();
-        }
+        get_codegen_backend(&None, None).print_passes();
         return None;
     }
 

compiler/rustc_interface/src/util.rs

@@ -73,7 +73,10 @@ pub fn create_session(
     let codegen_backend = if let Some(make_codegen_backend) = make_codegen_backend {
         make_codegen_backend(&sopts)
     } else {
-        get_codegen_backend(&sopts)
+        get_codegen_backend(
+            &sopts.maybe_sysroot,
+            sopts.debugging_opts.codegen_backend.as_ref().map(|name| &name[..]),
+        )
     };
 
     // target_override is documented to be called before init(), so this is okay
@@ -241,7 +244,13 @@ fn load_backend_from_dylib(path: &Path) -> fn() -> Box<dyn CodegenBackend> {
     }
 }
 
-pub fn get_codegen_backend(sopts: &config::Options) -> Box<dyn CodegenBackend> {
+/// Get the codegen backend based on the name and specified sysroot.
+///
+/// A name of `None` indicates that the default backend should be used.
+pub fn get_codegen_backend(
+    maybe_sysroot: &Option<PathBuf>,
+    backend_name: Option<&str>,
+) -> Box<dyn CodegenBackend> {
     static INIT: Once = Once::new();
 
     static mut LOAD: fn() -> Box<dyn CodegenBackend> = || unreachable!();
@@ -253,16 +262,11 @@ pub fn get_codegen_backend(sopts: &config::Options) -> Box<dyn CodegenBackend> {
         #[cfg(not(feature = "llvm"))]
         const DEFAULT_CODEGEN_BACKEND: &str = "cranelift";
 
-        let codegen_name = sopts
-            .debugging_opts
-            .codegen_backend
-            .as_ref()
-            .map(|name| &name[..])
-            .unwrap_or(DEFAULT_CODEGEN_BACKEND);
-
-        let backend = match codegen_name {
+        let backend = match backend_name.unwrap_or(DEFAULT_CODEGEN_BACKEND) {
             filename if filename.contains('.') => load_backend_from_dylib(filename.as_ref()),
-            codegen_name => get_builtin_codegen_backend(&sopts.maybe_sysroot, codegen_name),
+            #[cfg(feature = "llvm")]
+            "llvm" => rustc_codegen_llvm::LlvmCodegenBackend::new,
+            backend_name => get_codegen_sysroot(maybe_sysroot, backend_name),
         };
 
         unsafe {
@@ -387,17 +391,6 @@ fn sysroot_candidates() -> Vec<PathBuf> {
     }
 }
 
-pub fn get_builtin_codegen_backend(
-    maybe_sysroot: &Option<PathBuf>,
-    backend_name: &str,
-) -> fn() -> Box<dyn CodegenBackend> {
-    match backend_name {
-        #[cfg(feature = "llvm")]
-        "llvm" => rustc_codegen_llvm::LlvmCodegenBackend::new,
-        _ => get_codegen_sysroot(maybe_sysroot, backend_name),
-    }
-}
-
 pub fn get_codegen_sysroot(
     maybe_sysroot: &Option<PathBuf>,
     backend_name: &str,