Always statically link std into rustc_driver

src/bootstrap/src/bin/rustc.rs

@@ -92,10 +92,8 @@ fn main() {
     // Get the name of the crate we're compiling, if any.
     let crate_name = parse_value_from_args(&orig_args, "--crate-name");
 
-    // When statically linking `std` into `rustc_driver`, remove `-C prefer-dynamic`
-    if env::var("RUSTC_LINK_STD_INTO_RUSTC_DRIVER").unwrap() == "1"
-        && crate_name == Some("rustc_driver")
-    {
+    // When compiling `rustc_driver` remove `-C prefer-dynamic` to allow statically linking `std` into it
+    if crate_name == Some("rustc_driver") {
         if let Some(pos) = args.iter().enumerate().position(|(i, a)| {
             a == "-C" && args.get(i + 1).map(|a| a == "prefer-dynamic").unwrap_or(false)
         }) {

src/bootstrap/src/core/build_steps/compile.rs

@@ -2349,14 +2349,9 @@ impl CommandLineStep for Assemble {
             let is_proc_macro = proc_macros.contains(&filename);
             let is_dylib_or_debug = is_dylib(&f.path()) || is_debug_info(&filename);
 
-            // If we link statically to stdlib, do not copy the libstd dynamic library file
+            // `rustc_driver` statically links to stdlib, so do not copy the libstd dynamic library file
             let can_be_rustc_dynamic_dep =
-                if builder.link_std_into_rustc_driver(target_compiler.host) {
-                    let is_std = filename.starts_with("std-") || filename.starts_with("libstd-");
-                    !is_std
-                } else {
-                    true
-                };
+                !(filename.starts_with("std-") || filename.starts_with("libstd-"));
 
             if is_dylib_or_debug && can_be_rustc_dynamic_dep && !is_proc_macro {
                 builder.copy_link(&f.path(), &rustc_libdir.join(&filename), FileType::Regular);

src/bootstrap/src/core/builder/cargo.rs

@@ -1435,14 +1435,6 @@ impl Builder<'_> {
         if matches!(mode, Mode::Std) {
             rustflags.arg("-Cprefer-dynamic");
         }
-        if matches!(mode, Mode::Rustc) && !self.link_std_into_rustc_driver(target) {
-            rustflags.arg("-Cprefer-dynamic");
-        }
-
-        cargo.env(
-            "RUSTC_LINK_STD_INTO_RUSTC_DRIVER",
-            if self.link_std_into_rustc_driver(target) { "1" } else { "0" },
-        );
 
         // When building incrementally we default to a lower ThinLTO import limit
         // (unless explicitly specified otherwise). This will produce a somewhat

src/bootstrap/src/core/builder/mod.rs

@@ -1174,12 +1174,6 @@ impl<'a> Builder<'a> {
         cli_paths::match_paths_to_steps_and_run(self, v, paths);
     }
 
-    /// Returns if `std` should be statically linked into `rustc_driver`.
-    /// It's currently not done on `windows-gnu` due to linker bugs.
-    pub fn link_std_into_rustc_driver(&self, target: TargetSelection) -> bool {
-        !target.triple.ends_with("-windows-gnu")
-    }
-
     /// Obtain a compiler at a given stage and for a given host (i.e., this is the target that the
     /// compiler will run on, *not* the target it will build code for). Explicitly does not take
     /// `Compiler` since all `Compiler` instances are meant to be obtained through this function,