stabilize combining +bundle and +whole-archive link modifiers

Currently, combining +bundle and +whole-archive works only with
 #![feature(packed_bundled_libs)]
This crate feature is independent of the -Zpacked-bundled-libs
command line option.

This commit stabilizes the #![feature(packed_bundled_libs)] crate
feature and implicitly enables it only when the +bundle and
+whole-archive link modifiers are combined. This allows rlib
crates to use the +whole-archive link modifier with native
libraries and have all symbols included in the linked library
to be included in downstream staticlib crates that use the rlib as
a dependency. Other cases requiring the packed_bundled_libs
behavior still require the -Zpacked-bundled-libs command line
option, which can be stabilized independently in the future.

Per discussion on https://github.com/rust-lang/rust/issues/108081
there is no risk of regression stabilizing the crate feature in
this way because the combination of +bundle,+whole-archive link
modifiers was previously not allowed.

compiler/rustc_codegen_ssa/messages.ftl

@@ -44,8 +44,6 @@ codegen_ssa_ignoring_output = ignoring -o because multiple .{$extension} files w
 codegen_ssa_illegal_link_ordinal_format = illegal ordinal format in `link_ordinal`
     .note = an unsuffixed integer value, e.g., `1`, is expected
 
-codegen_ssa_incompatible_linking_modifiers = link modifiers combination `+bundle,+whole-archive` is unstable when generating rlibs
-
 codegen_ssa_insufficient_vs_code_product = VS Code is a different product, and is not sufficient.
 
 codegen_ssa_invalid_link_ordinal_nargs = incorrect number of arguments to `#[link_ordinal]`

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -365,15 +365,9 @@ fn link_rlib<'a>(
     // loaded from the libraries found here and then encode that into the
     // metadata of the rlib we're generating somehow.
     for lib in codegen_results.crate_info.used_libraries.iter() {
-        let NativeLibKind::Static { bundle: None | Some(true), whole_archive } = lib.kind else {
+        let NativeLibKind::Static { bundle: None | Some(true), .. } = lib.kind else {
             continue;
         };
-        if whole_archive == Some(true)
-            && flavor == RlibFlavor::Normal
-            && !codegen_results.crate_info.feature_packed_bundled_libs
-        {
-            sess.emit_err(errors::IncompatibleLinkingModifiers);
-        }
         if flavor == RlibFlavor::Normal && let Some(filename) = lib.filename {
             let path = find_native_static_library(filename.as_str(), true, &lib_search_paths, sess);
             let src = read(path).map_err(|e| sess.emit_fatal(errors::ReadFileError {message: e }))?;

compiler/rustc_codegen_ssa/src/base.rs

@@ -839,7 +839,6 @@ impl CrateInfo {
             dependency_formats: tcx.dependency_formats(()).clone(),
             windows_subsystem,
             natvis_debugger_visualizers: Default::default(),
-            feature_packed_bundled_libs: tcx.features().packed_bundled_libs,
         };
         let crates = tcx.crates(());
 

compiler/rustc_codegen_ssa/src/errors.rs

@@ -106,10 +106,6 @@ pub struct CreateTempDir {
     pub error: Error,
 }
 
-#[derive(Diagnostic)]
-#[diag(codegen_ssa_incompatible_linking_modifiers)]
-pub struct IncompatibleLinkingModifiers;
-
 #[derive(Diagnostic)]
 #[diag(codegen_ssa_add_native_library)]
 pub struct AddNativeLibrary {

compiler/rustc_codegen_ssa/src/lib.rs

@@ -164,7 +164,6 @@ pub struct CrateInfo {
     pub dependency_formats: Lrc<Dependencies>,
     pub windows_subsystem: Option<String>,
     pub natvis_debugger_visualizers: BTreeSet<DebuggerVisualizerFile>,
-    pub feature_packed_bundled_libs: bool, // unstable feature flag.
 }
 
 #[derive(Encodable, Decodable)]