Respect --target in get_backend_from_raw_matches

compiler/rustc_driver_impl/src/lib.rs

@@ -53,7 +53,7 @@ use rustc_middle::ty::TyCtxt;
 use rustc_parse::{new_parser_from_file, new_parser_from_source_str, unwrap_or_emit_fatal};
 use rustc_session::config::{
     CG_OPTIONS, ErrorOutputType, Input, OptionDesc, OutFileName, OutputType, UnstableOptions,
-    Z_OPTIONS, nightly_options,
+    Z_OPTIONS, nightly_options, parse_target_triple,
 };
 use rustc_session::getopts::{self, Matches};
 use rustc_session::lint::{Lint, LintId};
@@ -1129,17 +1129,18 @@ pub fn describe_flag_categories(early_dcx: &EarlyDiagCtxt, matches: &Matches) ->
 /// Get the codegen backend based on the raw [`Matches`].
 ///
 /// `rustc -vV` and `rustc -Cpasses=list` need to get the codegen backend before we have parsed all
-/// arguments and created a [`Session`]. This function reads `-Zcodegen-backend` and `--sysroot`
+/// arguments and created a [`Session`]. This function reads `-Zcodegen-backend`, `--target` and
-/// without validating any other arguments and loads the codegen backend based on these arguments.
+/// `--sysroot` without validating any other arguments and loads the codegen backend based on these
+/// arguments.
 fn get_backend_from_raw_matches(
     early_dcx: &EarlyDiagCtxt,
     matches: &Matches,
 ) -> Box<dyn CodegenBackend> {
     let debug_flags = matches.opt_strs("Z");
     let backend_name = debug_flags.iter().find_map(|x| x.strip_prefix("codegen-backend="));
-    let opts = config::Options::default();
+    let target = parse_target_triple(early_dcx, matches);
     let sysroot = filesearch::materialize_sysroot(matches.opt_str("sysroot").map(PathBuf::from));
-    let target = config::build_target_config(early_dcx, &opts, &sysroot);
+    let target = config::build_target_config(early_dcx, &target, &sysroot);
 
     get_codegen_backend(early_dcx, &sysroot, backend_name, &target)
 }

compiler/rustc_interface/src/interface.rs

@@ -383,7 +383,7 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
     crate::callbacks::setup_callbacks();
 
     let sysroot = filesearch::materialize_sysroot(config.opts.maybe_sysroot.clone());
-    let target = config::build_target_config(&early_dcx, &config.opts, &sysroot);
+    let target = config::build_target_config(&early_dcx, &config.opts.target_triple, &sysroot);
     let file_loader = config.file_loader.unwrap_or_else(|| Box::new(RealFileLoader));
     let path_mapping = config.opts.file_path_mapping();
     let hash_kind = config.opts.unstable_opts.src_hash_algorithm(&target);

compiler/rustc_interface/src/tests.rs

@@ -41,7 +41,8 @@ where
     let matches = optgroups().parse(args).unwrap();
     let sessopts = build_session_options(&mut early_dcx, &matches);
     let sysroot = filesearch::materialize_sysroot(sessopts.maybe_sysroot.clone());
-    let target = rustc_session::config::build_target_config(&early_dcx, &sessopts, &sysroot);
+    let target =
+        rustc_session::config::build_target_config(&early_dcx, &sessopts.target_triple, &sysroot);
     let hash_kind = sessopts.unstable_opts.src_hash_algorithm(&target);
     let checksum_hash_kind = sessopts.unstable_opts.checksum_hash_algorithm();
     let sm_inputs = Some(SourceMapInputs {

compiler/rustc_session/src/config.rs

@@ -1353,8 +1353,12 @@ pub fn build_configuration(sess: &Session, mut user_cfg: Cfg) -> Cfg {
     user_cfg
 }
 
-pub fn build_target_config(early_dcx: &EarlyDiagCtxt, opts: &Options, sysroot: &Path) -> Target {
+pub fn build_target_config(
-    match Target::search(&opts.target_triple, sysroot) {
+    early_dcx: &EarlyDiagCtxt,
+    target: &TargetTuple,
+    sysroot: &Path,
+) -> Target {
+    match Target::search(target, sysroot) {
         Ok((target, warnings)) => {
             for warning in warnings.warning_messages() {
                 early_dcx.early_warn(warning)