rust: oe-selftest issue fix with v1.82

A new feature "Link std statically in rustc_driver" was introduced 
in rust_1.82 [https://github.com/rust-lang/rust/pull/122362],and 
which is causing the below failure in oe-selftest.

Running unittests src/main.rs (build/x86_64-unknown-linux-gnu/stage1-rustc/
x86_64-poky-linux-gnu/release/deps/rustc_main-92223b15c9f2d827)
uploaded ".../build/x86_64-unknown-linux-gnu/stage1-rustc/x86_64-poky-linux-gnu/
release/deps/rustc_main-92223b15c9f2d827", waiting for result
/tmp/work/test4056/rustc_main-92223b15c9f2d827: error while loading shared 
libraries: librustc_driver-fb0866b1cd913c20.so: cannot open shared object file: No 
such file or directory

The rustc_main binary depends on the librustc_driver-*.so file. However, 
this file has not been copied to QEMU. If we manually copy the file into 
QEMU and export the LD_LIBRARY_PATH, the issue does not occur. Issue 
reprorted to upstream and reverted the buggy code as a workaround.

Upstream-Status: Inappropriate [reported at https://github.com/rust-lang/rust/issues/136237]

Signed-off-by: Deepesh Varatharajan <Deepesh.Varatharajan@windriver.com>
diff --git a/compiler/rustc/src/main.rs b/compiler/rustc/src/main.rs
index e9a7397557..29766fc9d8 100644
--- a/compiler/rustc/src/main.rs
+++ b/compiler/rustc/src/main.rs
@@ -1,5 +1,3 @@
-// We need this feature as it changes `dylib` linking behavior and allows us to link to `rustc_driver`.
-#![feature(rustc_private)]
 // Several crates are depended upon but unused so that they are present in the sysroot
 #![expect(unused_crate_dependencies)]

diff --git a/compiler/rustc_metadata/src/dependency_format.rs b/compiler/rustc_metadata/src/dependency_format.rs
index 39fa23766b..51d86b4009 100644
--- a/compiler/rustc_metadata/src/dependency_format.rs
+++ b/compiler/rustc_metadata/src/dependency_format.rs
@@ -51,7 +51,7 @@
 //! Additionally, the algorithm is geared towards finding *any* solution rather
 //! than finding a number of solutions (there are normally quite a few).

-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_index::IndexVec;
 use rustc_middle::bug;
@@ -159,46 +159,19 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
         }
         Linkage::Dynamic | Linkage::IncludedFromDylib => {}
     }
-
-    let all_dylibs = || {
-        tcx.crates(()).iter().filter(|&&cnum| {
-            !tcx.dep_kind(cnum).macros_only()
-                && (tcx.used_crate_source(cnum).dylib.is_some()
-                    || tcx.used_crate_source(cnum).sdylib_interface.is_some())
-        })
-    };
-
-    let mut upstream_in_dylibs = FxHashSet::default();
-
-    if tcx.features().rustc_private() {
-        // We need this to prevent users of `rustc_driver` from linking dynamically to `std`
-        // which does not work as `std` is also statically linked into `rustc_driver`.
-
-        // Find all libraries statically linked to upstream dylibs.
-        for &cnum in all_dylibs() {
-            let deps = tcx.dylib_dependency_formats(cnum);
-            for &(depnum, style) in deps.iter() {
-                if let RequireStatic = style {
-                    upstream_in_dylibs.insert(depnum);
-                }
-            }
-        }
-    }
-
     let mut formats = FxHashMap::default();

     // Sweep all crates for found dylibs. Add all dylibs, as well as their
     // dependencies, ensuring there are no conflicts. The only valid case for a
     // dependency to be relied upon twice is for both cases to rely on a dylib.
-    for &cnum in all_dylibs() {
-        if upstream_in_dylibs.contains(&cnum) {
-            info!("skipping dylib: {}", tcx.crate_name(cnum));
-            // If this dylib is also available statically linked to another dylib
-            // we try to use that instead.
+    for &cnum in tcx.crates(()).iter() {
+        if tcx.dep_kind(cnum).macros_only() {
             continue;
         }

         let name = tcx.crate_name(cnum);
+        let src = tcx.used_crate_source(cnum);
+        if src.dylib.is_some() {
         info!("adding dylib: {}", name);
         add_library(tcx, cnum, RequireDynamic, &mut formats, &mut unavailable_as_static);
         let deps = tcx.dylib_dependency_formats(cnum);
@@ -207,6 +182,7 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
             add_library(tcx, depnum, style, &mut formats, &mut unavailable_as_static);
         }
     }
+    }

     // Collect what we've got so far in the return vector.
     let last_crate = tcx.crates(()).len();
diff --git a/src/bootstrap/src/bin/rustc.rs b/src/bootstrap/src/bin/rustc.rs
index d04e2fbeb7..011c289d93 100644
--- a/src/bootstrap/src/bin/rustc.rs
+++ b/src/bootstrap/src/bin/rustc.rs
@@ -92,24 +92,6 @@ fn main() {
         rustc_real
     };

-    // 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")
-    {
-        if let Some(pos) = args.iter().enumerate().position(|(i, a)| {
-            a == "-C" && args.get(i + 1).map(|a| a == "prefer-dynamic").unwrap_or(false)
-        }) {
-            args.remove(pos);
-            args.remove(pos);
-        }
-        if let Some(pos) = args.iter().position(|a| a == "-Cprefer-dynamic") {
-            args.remove(pos);
-        }
-    }
-
     let mut cmd = match env::var_os("RUSTC_WRAPPER_REAL") {
         Some(wrapper) if !wrapper.is_empty() => {
             let mut cmd = Command::new(wrapper);
@@ -120,6 +102,9 @@ fn main() {
     };
     cmd.args(&args).env(dylib_path_var(), env::join_paths(&dylib_path).unwrap());

+    // Get the name of the crate we're compiling, if any.
+    let crate_name = parse_value_from_args(&orig_args, "--crate-name");
+
     if let Some(crate_name) = crate_name
         && let Some(target) = env::var_os("RUSTC_TIME")
         && (target == "all"
diff --git a/src/bootstrap/src/core/builder/cargo.rs b/src/bootstrap/src/core/builder/cargo.rs
index 0688a1d689..066e6bf53f 100644
--- a/src/bootstrap/src/core/builder/cargo.rs
+++ b/src/bootstrap/src/core/builder/cargo.rs
@@ -1146,7 +1146,7 @@ impl Builder<'_> {
         // When we build Rust dylibs they're all intended for intermediate
         // usage, so make sure we pass the -Cprefer-dynamic flag instead of
         // linking all deps statically into the dylib.
-        if matches!(mode, Mode::Std) {
+        if matches!(mode, Mode::Std | Mode::Rustc) {
             rustflags.arg("-Cprefer-dynamic");
         }
         if matches!(mode, Mode::Rustc) && !self.link_std_into_rustc_driver(target) {
diff --git a/src/tools/clippy/src/main.rs b/src/tools/clippy/src/main.rs
index c9853e53f3..c9af2138a7 100644
--- a/src/tools/clippy/src/main.rs
+++ b/src/tools/clippy/src/main.rs
@@ -1,6 +1,3 @@
-// We need this feature as it changes `dylib` linking behavior and allows us to link to
-// `rustc_driver`.
-#![feature(rustc_private)]
 // warn on lints, that are included in `rust-lang/rust`s bootstrap
 #![warn(rust_2018_idioms, unused_lifetimes)]

diff --git a/src/tools/clippy/tests/compile-test.rs b/src/tools/clippy/tests/compile-test.rs
index 9754254cdd..dd95cc71cd 100644
--- a/src/tools/clippy/tests/compile-test.rs
+++ b/src/tools/clippy/tests/compile-test.rs
@@ -1,4 +1,4 @@
-#![feature(rustc_private)]
+// warn on lints, that are included in `rust-lang/rust`s bootstrap
 #![warn(rust_2018_idioms, unused_lifetimes)]
 #![allow(unused_extern_crates)]

diff --git a/src/tools/rustdoc/main.rs b/src/tools/rustdoc/main.rs
index d4099cafe5..5b499a1fa1 100644
--- a/src/tools/rustdoc/main.rs
+++ b/src/tools/rustdoc/main.rs
@@ -1,6 +1,3 @@
-// We need this feature as it changes `dylib` linking behavior and allows us to link to `rustc_driver`.
-#![feature(rustc_private)]
-
 fn main() {
     rustdoc::main()
 }
diff --git a/src/tools/rustfmt/src/git-rustfmt/main.rs b/src/tools/rustfmt/src/git-rustfmt/main.rs
index b8b0432aa9..b5bd71e015 100644
--- a/src/tools/rustfmt/src/git-rustfmt/main.rs
+++ b/src/tools/rustfmt/src/git-rustfmt/main.rs
@@ -1,7 +1,3 @@
-// We need this feature as it changes `dylib` linking behavior and allows us to link to
-// `rustc_driver`.
-#![feature(rustc_private)]
-
 use std::env;
 use std::io::stdout;
 use std::path::{Path, PathBuf};
diff --git a/src/bootstrap/src/core/build_steps/compile.rs b/src/bootstrap/src/core/build_steps/compile.rs
index 27bbc8bd8f..a6fc4df2eb 100644
--- a/src/bootstrap/src/core/build_steps/compile.rs
+++ b/src/bootstrap/src/core/build_steps/compile.rs
@@ -2158,23 +2158,7 @@
         for f in builder.read_dir(&src_libdir) {
             let filename = f.file_name().into_string().unwrap();
 
-            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
-            // FIXME: Also do this for Windows once incremental post-optimization stage0 tests
-            // work without std.dll (see https://github.com/rust-lang/rust/pull/131188).
-            let can_be_rustc_dynamic_dep = if builder
-                .link_std_into_rustc_driver(target_compiler.host)
-                && !target_compiler.host.is_windows()
-            {
-                let is_std = filename.starts_with("std-") || filename.starts_with("libstd-");
-                !is_std
-            } else {
-                true
-            };
-
-            if is_dylib_or_debug && can_be_rustc_dynamic_dep && !is_proc_macro {
+            if (is_dylib(Path::new(&filename)) || is_debug_info(&filename)) && !proc_macros.contains(&filename) {
                 builder.copy_link(&f.path(), &rustc_libdir.join(&filename), FileType::Regular);
             }
         }
