use LinkSelfContained for -C link-self-contained

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -1688,7 +1688,7 @@ fn detect_self_contained_mingw(sess: &Session) -> bool {
 /// instead of being found somewhere on the host system.
 /// We only provide such support for a very limited number of targets.
 fn self_contained(sess: &Session, crate_type: CrateType) -> bool {
-    if let Some(self_contained) = sess.opts.cg.link_self_contained {
+    if let Some(self_contained) = sess.opts.cg.link_self_contained.explicitly_set {
         if sess.target.link_self_contained == LinkSelfContainedDefault::False {
             sess.emit_err(errors::UnsupportedLinkSelfContained);
         }

compiler/rustc_interface/src/tests.rs

@@ -8,6 +8,7 @@ use rustc_session::config::rustc_optgroups;
 use rustc_session::config::DebugInfo;
 use rustc_session::config::Input;
 use rustc_session::config::InstrumentXRay;
+use rustc_session::config::LinkSelfContained;
 use rustc_session::config::TraitSolver;
 use rustc_session::config::{build_configuration, build_session_options, to_crate_config};
 use rustc_session::config::{
@@ -579,7 +580,7 @@ fn test_codegen_options_tracking_hash() {
     untracked!(incremental, Some(String::from("abc")));
     // `link_arg` is omitted because it just forwards to `link_args`.
     untracked!(link_args, vec![String::from("abc"), String::from("def")]);
-    untracked!(link_self_contained, Some(true));
+    untracked!(link_self_contained, LinkSelfContained::on());
     untracked!(linker, Some(PathBuf::from("linker")));
     untracked!(linker_flavor, Some(LinkerFlavorCli::Gcc));
     untracked!(no_stack_check, true);

compiler/rustc_session/src/config.rs

@@ -253,6 +253,62 @@ bitflags::bitflags! {
     }
 }
 
+impl FromStr for LinkSelfContainedComponents {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(match s {
+            "crto" => LinkSelfContainedComponents::CRT_OBJECTS,
+            "libc" => LinkSelfContainedComponents::LIBC,
+            "unwind" => LinkSelfContainedComponents::UNWIND,
+            "linker" => LinkSelfContainedComponents::LINKER,
+            "sanitizers" => LinkSelfContainedComponents::SANITIZERS,
+            "mingw" => LinkSelfContainedComponents::MINGW,
+            _ => return Err(()),
+        })
+    }
+}
+
+impl LinkSelfContained {
+    /// Incorporates an enabled or disabled component as specified on the CLI, if possible.
+    /// For example: `+linker`, and `-crto`.
+    pub(crate) fn handle_cli_component(&mut self, component: &str) -> Result<(), ()> {
+        // Note that for example `-Cself-contained=y -Cself-contained=-linker` is not an explicit
+        // set of all values like `y` or `n` used to be. Therefore, if this flag had previously been
+        // set in bulk with its historical values, then manually setting a component clears that
+        // `explicitly_set` state.
+        if let Some(component_to_enable) = component.strip_prefix("+") {
+            self.explicitly_set = None;
+            self.components.insert(component_to_enable.parse()?);
+            Ok(())
+        } else if let Some(component_to_disable) = component.strip_prefix("-") {
+            self.explicitly_set = None;
+            self.components.remove(component_to_disable.parse()?);
+            Ok(())
+        } else {
+            Err(())
+        }
+    }
+
+    /// Turns all components on or off and records that this was done explicitly for compatibility
+    /// purposes.
+    pub(crate) fn set_all_explicitly(&mut self, enabled: bool) {
+        self.explicitly_set = Some(enabled);
+        self.components = if enabled {
+            LinkSelfContainedComponents::all()
+        } else {
+            LinkSelfContainedComponents::empty()
+        };
+    }
+
+    /// Helper creating a fully enabled `LinkSelfContained` instance. Used in tests.
+    pub fn on() -> Self {
+        let mut on = LinkSelfContained::default();
+        on.set_all_explicitly(true);
+        on
+    }
+}
+
 /// Used with `-Z assert-incr-state`.
 #[derive(Clone, Copy, PartialEq, Hash, Debug)]
 pub enum IncrementalStateAssertion {

compiler/rustc_session/src/options.rs

@@ -410,6 +410,8 @@ mod desc {
     pub const parse_split_dwarf_kind: &str =
         "one of supported split dwarf modes (`split` or `single`)";
     pub const parse_gcc_ld: &str = "one of: no value, `lld`";
+    pub const parse_link_self_contained: &str = "one of: `y`, `yes`, `on`, `n`, `no`, `off`, or a list of enabled (`+` prefix) and disabled (`-` prefix) \
+        components: `crto`, `libc`, `unwind`, `linker`, `sanitizers`, `mingw`";
     pub const parse_stack_protector: &str =
         "one of (`none` (default), `basic`, `strong`, or `all`)";
     pub const parse_branch_protection: &str =
@@ -1122,6 +1124,34 @@ mod parse {
         }
     }
 
+    pub(crate) fn parse_link_self_contained(slot: &mut LinkSelfContained, v: Option<&str>) -> bool {
+        // Whenever `-C link-self-contained` is passed without a value, it's an opt-in
+        // just like `parse_opt_bool`, the historical value of this flag.
+        //
+        // 1. Parse historical single bool values
+        let s = v.unwrap_or("y");
+        match s {
+            "y" | "yes" | "on" => {
+                slot.set_all_explicitly(true);
+                return true;
+            }
+            "n" | "no" | "off" => {
+                slot.set_all_explicitly(false);
+                return true;
+            }
+            _ => {}
+        }
+
+        // 2. Parse a list of enabled and disabled components.
+        for comp in s.split(",") {
+            if slot.handle_cli_component(comp).is_err() {
+                return false;
+            }
+        }
+
+        true
+    }
+
     pub(crate) fn parse_wasi_exec_model(slot: &mut Option<WasiExecModel>, v: Option<&str>) -> bool {
         match v {
             Some("command") => *slot = Some(WasiExecModel::Command),
@@ -1265,9 +1295,9 @@ options! {
     #[rustc_lint_opt_deny_field_access("use `Session::link_dead_code` instead of this field")]
     link_dead_code: Option<bool> = (None, parse_opt_bool, [TRACKED],
         "keep dead code at link time (useful for code coverage) (default: no)"),
-    link_self_contained: Option<bool> = (None, parse_opt_bool, [UNTRACKED],
+    link_self_contained: LinkSelfContained = (LinkSelfContained::default(), parse_link_self_contained, [UNTRACKED],
         "control whether to link Rust provided C objects/libraries or rely
-        on C toolchain installed in the system"),
+        on a C toolchain or linker installed in the system"),
     linker: Option<PathBuf> = (None, parse_opt_pathbuf, [UNTRACKED],
         "system linker to link outputs with"),
     linker_flavor: Option<LinkerFlavorCli> = (None, parse_linker_flavor, [UNTRACKED],