4 files changed, 21 insertions, 2 deletions
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index e2d36f6a4e2..a9d9236d318 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -1169,6 +1169,10 @@ impl OutputFilenames {
             .unwrap_or_else(|| OutFileName::Real(self.output_path(flavor)))
     }
 
+    pub fn interface_path(&self) -> PathBuf {
+        self.out_directory.join(format!("lib{}.rs", self.crate_stem))
+    }
+
     /// Gets the output path where a compilation artifact of the given type
     /// should be placed on disk.
     fn output_path(&self, flavor: OutputType) -> PathBuf {
@@ -1452,13 +1456,17 @@ pub enum CrateType {
     Staticlib,
     Cdylib,
     ProcMacro,
+    Sdylib,
 }
 
 impl CrateType {
     pub fn has_metadata(self) -> bool {
         match self {
             CrateType::Rlib | CrateType::Dylib | CrateType::ProcMacro => true,
-            CrateType::Executable | CrateType::Cdylib | CrateType::Staticlib => false,
+            CrateType::Executable
+            | CrateType::Cdylib
+            | CrateType::Staticlib
+            | CrateType::Sdylib => false,
         }
     }
 }
@@ -2818,6 +2826,7 @@ pub fn parse_crate_types_from_list(list_list: Vec<String>) -> Result<Vec<CrateTy
                 "cdylib" => CrateType::Cdylib,
                 "bin" => CrateType::Executable,
                 "proc-macro" => CrateType::ProcMacro,
+                "sdylib" => CrateType::Sdylib,
                 _ => {
                     return Err(format!(
                         "unknown crate type: `{part}`, expected one of: \
@@ -2915,6 +2924,7 @@ impl fmt::Display for CrateType {
             CrateType::Staticlib => "staticlib".fmt(f),
             CrateType::Cdylib => "cdylib".fmt(f),
             CrateType::ProcMacro => "proc-macro".fmt(f),
+            CrateType::Sdylib => "sdylib".fmt(f),
         }
     }
 }
diff --git a/compiler/rustc_session/src/cstore.rs b/compiler/rustc_session/src/cstore.rs
index c8a5c22ad12..4cfc745dec2 100644
--- a/compiler/rustc_session/src/cstore.rs
+++ b/compiler/rustc_session/src/cstore.rs
@@ -27,6 +27,7 @@ pub struct CrateSource {
     pub dylib: Option<(PathBuf, PathKind)>,
     pub rlib: Option<(PathBuf, PathKind)>,
     pub rmeta: Option<(PathBuf, PathKind)>,
+    pub sdylib_interface: Option<(PathBuf, PathKind)>,
 }
 
 impl CrateSource {
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 5f4695fb184..440e8f808c7 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -2113,6 +2113,8 @@ options! {
         "emit noalias metadata for box (default: yes)"),
     branch_protection: Option<BranchProtection> = (None, parse_branch_protection, [TRACKED],
         "set options for branch target identification and pointer authentication on AArch64"),
+    build_sdylib_interface: bool = (false, parse_bool, [UNTRACKED],
+        "whether the stable interface is being built"),
     cf_protection: CFProtection = (CFProtection::None, parse_cfprotection, [TRACKED],
         "instrument control-flow architecture protection"),
     check_cfg_all_expected: bool = (false, parse_bool, [UNTRACKED],
diff --git a/compiler/rustc_session/src/output.rs b/compiler/rustc_session/src/output.rs
index 46dae9144cd..cba70b5bd5d 100644
--- a/compiler/rustc_session/src/output.rs
+++ b/compiler/rustc_session/src/output.rs
@@ -98,7 +98,7 @@ pub fn filename_for_input(
         CrateType::Rlib => {
             OutFileName::Real(outputs.out_directory.join(&format!("lib{libname}.rlib")))
         }
-        CrateType::Cdylib | CrateType::ProcMacro | CrateType::Dylib => {
+        CrateType::Cdylib | CrateType::ProcMacro | CrateType::Dylib | CrateType::Sdylib => {
             let (prefix, suffix) = (&sess.target.dll_prefix, &sess.target.dll_suffix);
             OutFileName::Real(outputs.out_directory.join(&format!("{prefix}{libname}{suffix}")))
         }
@@ -167,6 +167,7 @@ pub const CRATE_TYPES: &[(Symbol, CrateType)] = &[
     (sym::staticlib, CrateType::Staticlib),
     (sym::proc_dash_macro, CrateType::ProcMacro),
     (sym::bin, CrateType::Executable),
+    (sym::sdylib, CrateType::Sdylib),
 ];
 
 pub fn categorize_crate_type(s: Symbol) -> Option<CrateType> {
@@ -187,6 +188,11 @@ pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<C
         return vec![CrateType::Executable];
     }
 
+    // Shadow `sdylib` crate type in interface build.
+    if session.opts.unstable_opts.build_sdylib_interface {
+        return vec![CrateType::Rlib];
+    }
+
     // Only check command line flags if present. If no types are specified by
     // command line, then reuse the empty `base` Vec to hold the types that
     // will be found in crate attributes.