Stabilise link-self-contained option

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -1084,7 +1084,7 @@ fn get_crt_libs_path(sess: &Session) -> Option<PathBuf> {
 
 fn get_object_file_path(sess: &Session, name: &str, self_contained: bool) -> PathBuf {
     // prefer system {,dll}crt2.o libs, see get_crt_libs_path comment for more details
-    if sess.opts.debugging_opts.link_self_contained.is_none()
+    if sess.opts.cg.link_self_contained.is_none()
         && sess.target.target.llvm_target.contains("windows-gnu")
     {
         if let Some(compiler_libs_path) = get_crt_libs_path(sess) {
@@ -1289,7 +1289,7 @@ fn link_output_kind(sess: &Session, crate_type: CrateType) -> LinkOutputKind {
 /// Whether we link to our own CRT objects instead of relying on gcc to pull them.
 /// We only provide such support for a very limited number of targets.
 fn crt_objects_fallback(sess: &Session, crate_type: CrateType) -> bool {
-    if let Some(self_contained) = sess.opts.debugging_opts.link_self_contained {
+    if let Some(self_contained) = sess.opts.cg.link_self_contained {
         return self_contained;
     }
 
@@ -1499,7 +1499,7 @@ fn link_local_crate_native_libs_and_dependent_crate_libs<'a, B: ArchiveBuilder<'
 /// Add sysroot and other globally set directories to the directory search list.
 fn add_library_search_dirs(cmd: &mut dyn Linker, sess: &Session, self_contained: bool) {
     // Prefer system mingw-w64 libs, see get_crt_libs_path comment for more details.
-    if sess.opts.debugging_opts.link_self_contained.is_none()
+    if sess.opts.cg.link_self_contained.is_none()
         && cfg!(windows)
         && sess.target.target.llvm_target.contains("windows-gnu")
     {

compiler/rustc_interface/src/tests.rs

@@ -402,6 +402,7 @@ fn test_codegen_options_tracking_hash() {
     // `link_arg` is omitted because it just forwards to `link_args`.
     untracked!(link_args, vec![String::from("abc"), String::from("def")]);
     untracked!(link_dead_code, Some(true));
+    untracked!(link_self_contained, Some(true));
     untracked!(linker, Some(PathBuf::from("linker")));
     untracked!(linker_flavor, Some(LinkerFlavor::Gcc));
     untracked!(no_stack_check, true);

compiler/rustc_session/src/options.rs

@@ -719,6 +719,9 @@ options! {CodegenOptions, CodegenSetter, basic_codegen_options,
         "extra arguments to append to the linker invocation (space separated)"),
     link_dead_code: Option<bool> = (None, parse_opt_bool, [UNTRACKED],
         "keep dead code at link time (useful for code coverage) (default: no)"),
+    link_self_contained: Option<bool> = (None, parse_opt_bool, [UNTRACKED],
+        "control whether to link Rust provided C objects/libraries or rely
+        on C toolchain installed in the system"),
     linker: Option<PathBuf> = (None, parse_opt_pathbuf, [UNTRACKED],
         "system linker to link outputs with"),
     linker_flavor: Option<LinkerFlavor> = (None, parse_linker_flavor, [UNTRACKED],
@@ -894,9 +897,6 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "keep hygiene data after analysis (default: no)"),
     link_native_libraries: bool = (true, parse_bool, [UNTRACKED],
         "link native libraries in the linker invocation (default: yes)"),
-    link_self_contained: Option<bool> = (None, parse_opt_bool, [TRACKED],
-        "control whether to link Rust provided C objects/libraries or rely
-         on C toolchain installed in the system"),
     link_only: bool = (false, parse_bool, [TRACKED],
         "link the `.rlink` file generated by `-Z no-link` (default: no)"),
     llvm_time_trace: bool = (false, parse_bool, [UNTRACKED],

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

@@ -200,6 +200,18 @@ the following values:
 An example of when this flag might be useful is when trying to construct code coverage
 metrics.
 
+## link-self-contained
+
+On targets that support it this flag controls whether the linker will use libraries and objects
+shipped with Rust instead or those in the system.
+It takes one of the following values:
+
+* no value: rustc will use heuristic to disable self-contained mode if system has necessary tools.
+* `y`, `yes`, `on`: use only libraries/objects shipped with Rust.
+* `n`, `no`, or `off`: rely on the user or the linker to provide non-Rust libraries/objects.
+
+This allows overriding cases when detection fails or user wants to use shipped libraries.
+
 ## linker
 
 This flag controls which linker `rustc` invokes to link your code. It takes a