Stabilize -Zembed-metadata

compiler/rustc_interface/src/tests.rs

@@ -639,6 +639,7 @@ fn test_codegen_options_tracking_hash() {
     tracked!(debuginfo, DebugInfo::Limited);
     tracked!(dwarf_version, Some(5));
     tracked!(embed_bitcode, false);
+    tracked!(embed_metadata, Some(false));
     tracked!(force_frame_pointers, FramePointer::Always);
     tracked!(force_unwind_tables, Some(true));
     tracked!(instrument_coverage, InstrumentCoverage::Yes);
@@ -819,7 +820,7 @@ fn test_unstable_options_tracking_hash() {
     tracked!(direct_access_external_data, Some(true));
     tracked!(dual_proc_macros, true);
     tracked!(dwarf_version, Some(5));
-    tracked!(embed_metadata, false);
+    tracked!(embed_metadata, Some(false));
     tracked!(embed_source, true);
     tracked!(export_executable_symbols, true);
     tracked!(fewer_names, Some(true));

compiler/rustc_metadata/src/diagnostics.rs

@@ -325,7 +325,7 @@ impl Diagnostic<'_> for MultipleCandidates {
 
 #[derive(Diagnostic)]
 #[diag(
-    "only metadata stub found for `{$flavor}` dependency `{$crate_name}` please provide path to the corresponding .rmeta file with full metadata"
+    "only metadata stub found for `{$flavor}` dependency `{$crate_name}`. Please provide path to the corresponding .rmeta file with full metadata"
 )]
 pub(crate) struct FullMetadataNotFound {
     #[primary_span]

compiler/rustc_metadata/src/fs.rs

@@ -48,13 +48,12 @@ pub fn encode_and_write_metadata(tcx: TyCtxt<'_>) -> Result<EncodedMetadata, Err
         .unwrap_or_else(|err| tcx.dcx().emit_fatal(FailedCreateTempdir { err }));
     let metadata_tmpdir = MaybeTempDir::new(metadata_tmpdir, tcx.sess.opts.cg.save_temps);
     let metadata_filename = metadata_tmpdir.as_ref().join("full.rmeta");
-    let metadata_stub_filename = if !tcx.sess.opts.unstable_opts.embed_metadata
-        && !tcx.crate_types().contains(&CrateType::ProcMacro)
-    {
-        Some(metadata_tmpdir.as_ref().join("stub.rmeta"))
-    } else {
-        None
-    };
+    let metadata_stub_filename =
+        if !tcx.sess.embed_metadata() && !tcx.crate_types().contains(&CrateType::ProcMacro) {
+            Some(metadata_tmpdir.as_ref().join("stub.rmeta"))
+        } else {
+            None
+        };
 
     if tcx.needs_metadata() {
         encode_metadata(tcx, &metadata_filename, metadata_stub_filename.as_deref());

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -237,7 +237,7 @@ pub(crate) struct CrateHeader {
     /// Stubs do not contain the full metadata (it will be typically stored
     /// in a separate rmeta file).
     ///
-    /// This is used inside rlibs and dylibs when using `-Zembed-metadata=no`.
+    /// This is used inside rlibs and dylibs when using `-Cembed-metadata=no`.
     pub(crate) is_stub: bool,
 }
 

compiler/rustc_session/src/config.rs

@@ -2944,6 +2944,10 @@ pub fn build_session_options(early_dcx: &mut EarlyDiagCtxt, matches: &getopts::M
             .early_warn("using -Z remark-dir without enabling remarks using e.g. -C remark=all");
     }
 
+    if cg.embed_metadata.is_some() && unstable_opts.embed_metadata.is_some() {
+        early_dcx.early_fatal("can't use both -Z embed-metadata and -C embed-metadata");
+    }
+
     let externs = parse_externs(early_dcx, matches, &unstable_opts);
 
     let remap_path_prefix = parse_remap_path_prefix(early_dcx, matches);

compiler/rustc_session/src/options.rs

@@ -2231,6 +2231,8 @@ options! {
         "version of DWARF debug information to emit (default: 2 or 4, depending on platform)"),
     embed_bitcode: bool = (true, parse_bool, [TRACKED],
         "emit bitcode in rlibs (default: yes)"),
+    embed_metadata: Option<bool> = (None, parse_opt_bool, [TRACKED],
+        "embed metadata in rlibs and dylibs (default: yes)"),
     extra_filename: String = (String::new(), parse_string, [UNTRACKED],
         "extra data to put in each output filename"),
     force_frame_pointers: FramePointer = (FramePointer::MayOmit, parse_frame_pointer, [TRACKED],
@@ -2494,7 +2496,8 @@ options! {
         them only if an error has not been emitted"),
     ehcont_guard: bool = (false, parse_bool, [TRACKED],
         "generate Windows EHCont Guard tables"),
-    embed_metadata: bool = (true, parse_bool, [TRACKED],
+    // FIXME(kobzol): remove in 2027
+    embed_metadata: Option<bool> = (None, parse_opt_bool, [TRACKED],
         "embed metadata in rlibs and dylibs (default: yes)"),
     embed_source: bool = (false, parse_bool, [TRACKED],
         "embed source text in DWARF debug sections (default: no)"),

compiler/rustc_session/src/session.rs

@@ -954,6 +954,11 @@ impl Session {
             }
         }
     }
+
+    /// Should metadata be embedded within .rlib and .dylib files?
+    pub fn embed_metadata(&self) -> bool {
+        self.opts.cg.embed_metadata.or(self.opts.unstable_opts.embed_metadata).unwrap_or(true)
+    }
 }
 
 // JUSTIFICATION: defn of the suggested wrapper fns

src/doc/rustc/src/codegen-options/index.md

@@ -152,6 +152,14 @@ at start-up, because the combination is invalid.
 > reason for that is that it's how it was for rustc 1.44 and prior. In 1.45 this
 > option was added to turn off what had always been the default.
 
+## embed-metadata
+
+This option instructs `rustc` to include the full metadata in `rlib` and `dylib`
+crate types. The default value is `yes` (enabled). If disabled (`no`), only stub
+metadata will be stored in these files, to reduce their size on disk. When using
+`-Cembed-metadata=no`, you will probably want to use `--emit=metadata` to produce
+the full metadata into a separate `.rmeta` file.
+
 ## extra-filename
 
 This option allows you to put extra data in each output filename. It takes a

src/doc/unstable-book/src/compiler-flags/embed-metadata.md

@@ -1,3 +1,5 @@
 ## `embed-metadata`
 
 This option instructs `rustc` to include the full metadata in `rlib` and `dylib` crate types. The default value is `yes` (enabled). If disabled (`no`), only stub metadata will be stored in these files, to reduce their size on disk. When using `-Zembed-metadata=no`, you will probably want to use `--emit=metadata` to produce the full metadata into a separate `.rmeta` file.
+
+Note that this flag has been stabilized as `-Cembed-metadata`. The unstable variant of the flag is provided purely for making the migration easier; it will be removed in the future.

tests/run-make/embed-metadata/rmake.rs

@@ -1,8 +1,7 @@
 //@ ignore-cross-compile
 //@ needs-crate-type: dylib
 
-// Tests the -Zembed-metadata compiler flag.
-// Tracking issue: https://github.com/rust-lang/rust/issues/139165
+// Tests the -Cembed-metadata compiler flag.
 
 use run_make_support::rfs::{create_dir, remove_file, rename};
 use run_make_support::{Rustc, dynamic_lib_name, path, run_in_tmpdir, rust_lib_name, rustc};
@@ -78,7 +77,7 @@ fn lookup_rmeta_missing(kind: LibraryKind) {
 fn build_dep_rustc(kind: LibraryKind) -> Rustc {
     let mut dep_rustc = rustc();
     dep_rustc
-        .arg("-Zembed-metadata=no")
+        .arg("-Cembed-metadata=no")
         .crate_type(kind.crate_type())
         .input("dep1.rs")
         .emit("metadata,link");

tests/run-make/metadata-stub-incremental-reuse/rmake.rs

@@ -1,6 +1,6 @@
 //@ needs-target-std
 //
-// Under `-Zembed-metadata=no` the rlib carries only a metadata stub, which
+// Under `-Cembed-metadata=no` the rlib carries only a metadata stub, which
 // rustc writes as a separate file alongside the full metadata. Recompiling
 // with `-C incremental` can reuse the full metadata from a work product, and
 // the stub must still be produced on that path.
@@ -13,7 +13,7 @@ fn build(out_dir: &str, incremental: &str) {
         .crate_name("foo")
         .crate_type("lib")
         .emit("dep-info,metadata,link")
-        .arg("-Zembed-metadata=no")
+        .arg("-Cembed-metadata=no")
         .incremental(incremental)
         .out_dir(out_dir)
         .run();