unify `LinkSelfContained` and `LinkSelfContainedDefault`

Removes the backwards-compatible `LinkSelfContainedDefault`, by
incorporating the remaining specifics into `LinkSelfContained`.

Then renames the modern options to keep the old name.

8 files changed, 60 insertions, 91 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index fb79df4f791..104f30697bd 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -23,7 +23,7 @@ use rustc_session::utils::NativeLibKind;
 use rustc_session::{filesearch, Session};
 use rustc_span::symbol::Symbol;
 use rustc_target::spec::crt_objects::CrtObjects;
-use rustc_target::spec::LinkSelfContained;
+use rustc_target::spec::LinkSelfContainedDefault;
 use rustc_target::spec::{Cc, LinkOutputKind, LinkerFlavor, Lld, PanicStrategy};
 use rustc_target::spec::{RelocModel, RelroLevel, SanitizerSet, SplitDebuginfo};
 
@@ -1714,9 +1714,9 @@ fn self_contained(sess: &Session, crate_type: CrateType) -> bool {
     }
 
     match sess.target.link_self_contained {
-        LinkSelfContained::True => true,
-        LinkSelfContained::False => false,
-        LinkSelfContained::WithComponents(components) => {
+        LinkSelfContainedDefault::False => false,
+        LinkSelfContainedDefault::True => true,
+        LinkSelfContainedDefault::WithComponents(components) => {
             if components.is_all() {
                 true
             } else if components.is_empty() {
@@ -1733,8 +1733,8 @@ fn self_contained(sess: &Session, crate_type: CrateType) -> bool {
         // FIXME: Find a better heuristic for "native musl toolchain is available",
         // based on host and linker path, for example.
         // (https://github.com/rust-lang/rust/pull/71769#issuecomment-626330237).
-        LinkSelfContained::InferredForMusl => sess.crt_static(Some(crate_type)),
-        LinkSelfContained::InferredForMingw => {
+        LinkSelfContainedDefault::InferredForMusl => sess.crt_static(Some(crate_type)),
+        LinkSelfContainedDefault::InferredForMingw => {
             sess.host == sess.target
                 && sess.target.vendor != "uwp"
                 && detect_self_contained_mingw(&sess)
diff --git a/compiler/rustc_target/src/spec/crt_objects.rs b/compiler/rustc_target/src/spec/crt_objects.rs
index c126390f5a9..53f710b8f9e 100644
--- a/compiler/rustc_target/src/spec/crt_objects.rs
+++ b/compiler/rustc_target/src/spec/crt_objects.rs
@@ -40,11 +40,9 @@
 //! but not gcc's. As a result rustc cannot link with C++ static libraries (#36710)
 //! when linking in self-contained mode.
 
-use crate::json::{Json, ToJson};
 use crate::spec::LinkOutputKind;
 use std::borrow::Cow;
 use std::collections::BTreeMap;
-use std::str::FromStr;
 
 pub type CrtObjects = BTreeMap<LinkOutputKind, Vec<Cow<'static, str>>>;
 
@@ -123,39 +121,3 @@ pub(super) fn pre_wasi_self_contained() -> CrtObjects {
 pub(super) fn post_wasi_self_contained() -> CrtObjects {
     new(&[])
 }
-
-/// Which logic to use to determine whether to use self-contained linking mode
-/// if `-Clink-self-contained` is not specified explicitly.
-#[derive(Clone, Copy, PartialEq, Hash, Debug)]
-pub enum LinkSelfContainedDefault {
-    False,
-    True,
-    Musl,
-    Mingw,
-}
-
-impl FromStr for LinkSelfContainedDefault {
-    type Err = ();
-
-    fn from_str(s: &str) -> Result<LinkSelfContainedDefault, ()> {
-        Ok(match s {
-            "false" => LinkSelfContainedDefault::False,
-            "true" | "wasm" => LinkSelfContainedDefault::True,
-            "musl" => LinkSelfContainedDefault::Musl,
-            "mingw" => LinkSelfContainedDefault::Mingw,
-            _ => return Err(()),
-        })
-    }
-}
-
-impl ToJson for LinkSelfContainedDefault {
-    fn to_json(&self) -> Json {
-        match *self {
-            LinkSelfContainedDefault::False => "false",
-            LinkSelfContainedDefault::True => "true",
-            LinkSelfContainedDefault::Musl => "musl",
-            LinkSelfContainedDefault::Mingw => "mingw",
-        }
-        .to_json()
-    }
-}
diff --git a/compiler/rustc_target/src/spec/linux_musl_base.rs b/compiler/rustc_target/src/spec/linux_musl_base.rs
index 318d06e9889..b698bcbcef6 100644
--- a/compiler/rustc_target/src/spec/linux_musl_base.rs
+++ b/compiler/rustc_target/src/spec/linux_musl_base.rs
@@ -1,6 +1,5 @@
 use crate::spec::crt_objects;
-use crate::spec::LinkSelfContained;
-use crate::spec::TargetOptions;
+use crate::spec::{LinkSelfContainedDefault, TargetOptions};
 
 pub fn opts() -> TargetOptions {
     let mut base = super::linux_base::opts();
@@ -8,7 +7,7 @@ pub fn opts() -> TargetOptions {
     base.env = "musl".into();
     base.pre_link_objects_self_contained = crt_objects::pre_musl_self_contained();
     base.post_link_objects_self_contained = crt_objects::post_musl_self_contained();
-    base.link_self_contained = LinkSelfContained::InferredForMusl;
+    base.link_self_contained = LinkSelfContainedDefault::InferredForMusl;
 
     // These targets statically link libc by default
     base.crt_static_default = true;
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 2d8b1b23980..9141b169ae9 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -38,7 +38,7 @@ use crate::abi::call::Conv;
 use crate::abi::{Endian, Integer, Size, TargetDataLayout, TargetDataLayoutErrors};
 use crate::json::{Json, ToJson};
 use crate::spec::abi::{lookup as lookup_abi, Abi};
-use crate::spec::crt_objects::{CrtObjects, LinkSelfContainedDefault};
+use crate::spec::crt_objects::CrtObjects;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_fs_util::try_canonicalize;
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
@@ -542,7 +542,7 @@ impl ToJson for LinkerFlavorCli {
 /// - explicitly enabling some of the self-contained linking components, e.g. the linker component
 ///   to use `rust-lld`
 #[derive(Clone, Copy, PartialEq, Debug)]
-pub enum LinkSelfContained {
+pub enum LinkSelfContainedDefault {
     /// The target spec explicitly enables self-contained linking.
     True,
 
@@ -560,10 +560,25 @@ pub enum LinkSelfContained {
     WithComponents(LinkSelfContainedComponents),
 }
 
-impl ToJson for LinkSelfContained {
+/// Parses a backwards-compatible `-Clink-self-contained` option string, without components.
+impl FromStr for LinkSelfContainedDefault {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<LinkSelfContainedDefault, ()> {
+        Ok(match s {
+            "false" => LinkSelfContainedDefault::False,
+            "true" | "wasm" => LinkSelfContainedDefault::True,
+            "musl" => LinkSelfContainedDefault::InferredForMusl,
+            "mingw" => LinkSelfContainedDefault::InferredForMingw,
+            _ => return Err(()),
+        })
+    }
+}
+
+impl ToJson for LinkSelfContainedDefault {
     fn to_json(&self) -> Json {
         match *self {
-            LinkSelfContained::WithComponents(components) => {
+            LinkSelfContainedDefault::WithComponents(components) => {
                 // Serialize the components in a json object's `components` field, to prepare for a
                 // future where `crt-objects-fallback` is removed from the json specs and
                 // incorporated as a field here.
@@ -572,29 +587,31 @@ impl ToJson for LinkSelfContained {
                 map.to_json()
             }
 
-            // Stable values backwards-compatible with `LinkSelfContainedDefault`
-            LinkSelfContained::True => "true".to_json(),
-            LinkSelfContained::False => "false".to_json(),
-            LinkSelfContained::InferredForMusl => "musl".to_json(),
-            LinkSelfContained::InferredForMingw => "mingw".to_json(),
+            // Stable backwards-compatible values
+            LinkSelfContainedDefault::True => "true".to_json(),
+            LinkSelfContainedDefault::False => "false".to_json(),
+            LinkSelfContainedDefault::InferredForMusl => "musl".to_json(),
+            LinkSelfContainedDefault::InferredForMingw => "mingw".to_json(),
         }
     }
 }
 
-impl LinkSelfContained {
+impl LinkSelfContainedDefault {
     /// Returns whether the target spec has self-contained linking explicitly disabled. Used to emit
     /// errors if the user then enables it on the CLI.
     pub fn is_disabled(self) -> bool {
-        self == LinkSelfContained::False
+        self == LinkSelfContainedDefault::False
     }
 
     /// Returns whether the target spec explictly requests self-contained linking, i.e. not via
     /// inference.
     pub fn is_linker_enabled(self) -> bool {
         match self {
-            LinkSelfContained::True => true,
-            LinkSelfContained::False => false,
-            LinkSelfContained::WithComponents(c) => c.contains(LinkSelfContainedComponents::LINKER),
+            LinkSelfContainedDefault::True => true,
+            LinkSelfContainedDefault::False => false,
+            LinkSelfContainedDefault::WithComponents(c) => {
+                c.contains(LinkSelfContainedComponents::LINKER)
+            }
             _ => false,
         }
     }
@@ -604,23 +621,12 @@ impl LinkSelfContained {
     /// - the other variants as a backwards-compatible `crt-objects-fallback` string
     fn json_key(self) -> &'static str {
         match self {
-            LinkSelfContained::WithComponents(_) => "link-self-contained",
+            LinkSelfContainedDefault::WithComponents(_) => "link-self-contained",
             _ => "crt-objects-fallback",
         }
     }
 }
 
-impl From<LinkSelfContainedDefault> for LinkSelfContained {
-    fn from(value: LinkSelfContainedDefault) -> Self {
-        match value {
-            LinkSelfContainedDefault::True => LinkSelfContained::True,
-            LinkSelfContainedDefault::False => LinkSelfContained::False,
-            LinkSelfContainedDefault::Musl => LinkSelfContained::InferredForMusl,
-            LinkSelfContainedDefault::Mingw => LinkSelfContained::InferredForMingw,
-        }
-    }
-}
-
 bitflags::bitflags! {
     #[derive(Default)]
     /// The `-C link-self-contained` components that can individually be enabled or disabled.
@@ -1888,7 +1894,7 @@ pub struct TargetOptions {
     pub post_link_objects_self_contained: CrtObjects,
     /// Behavior for the self-contained linking mode: inferred for some targets, or explicitly
     /// enabled (in bulk, or with individual components).
-    pub link_self_contained: LinkSelfContained,
+    pub link_self_contained: LinkSelfContainedDefault,
 
     /// Linker arguments that are passed *before* any user-defined libraries.
     pub pre_link_args: LinkArgs,
@@ -2363,7 +2369,7 @@ impl Default for TargetOptions {
             post_link_objects: Default::default(),
             pre_link_objects_self_contained: Default::default(),
             post_link_objects_self_contained: Default::default(),
-            link_self_contained: LinkSelfContained::False,
+            link_self_contained: LinkSelfContainedDefault::False,
             pre_link_args: LinkArgs::new(),
             pre_link_args_json: LinkArgsCli::new(),
             late_link_args: LinkArgs::new(),
@@ -2844,7 +2850,7 @@ impl Target {
                 }
                 Ok::<(), String>(())
             } );
-            ($key_name:ident, LinkSelfContained) => ( {
+            ($key_name:ident, link_self_contained_components) => ( {
                 // Skeleton of what needs to be parsed:
                 //
                 // ```
@@ -2873,18 +2879,18 @@ impl Target {
                                 _ => return Err(format!("not a string: {:?}", s)),
                             };
                         }
-                        base.$key_name = LinkSelfContained::WithComponents(components);
+                        base.$key_name = LinkSelfContainedDefault::WithComponents(components);
                     } else {
                         incorrect_type.push(name)
                     }
                 }
                 Ok::<(), String>(())
             } );
-            ($key_name:ident = $json_name:expr, LinkSelfContainedDefault) => ( {
+            ($key_name:ident = $json_name:expr, link_self_contained_backwards_compatible) => ( {
                 let name = $json_name;
                 obj.remove(name).and_then(|o| o.as_str().and_then(|s| {
                     match s.parse::<LinkSelfContainedDefault>() {
-                        Ok(lsc_default) => base.$key_name = lsc_default.into(),
+                        Ok(lsc_default) => base.$key_name = lsc_default,
                         _ => return Some(Err(format!("'{}' is not a valid `-Clink-self-contained` default. \
                                                       Use 'false', 'true', 'musl' or 'mingw'", s))),
                     }
@@ -3034,9 +3040,12 @@ impl Target {
         key!(pre_link_objects_self_contained = "pre-link-objects-fallback", link_objects);
         key!(post_link_objects_self_contained = "post-link-objects-fallback", link_objects);
         // Deserializes the backwards-compatible variants of `-Clink-self-contained`
-        key!(link_self_contained = "crt-objects-fallback", LinkSelfContainedDefault)?;
+        key!(
+            link_self_contained = "crt-objects-fallback",
+            link_self_contained_backwards_compatible
+        )?;
         // Deserializes the components variant of `-Clink-self-contained`
-        key!(link_self_contained, LinkSelfContained)?;
+        key!(link_self_contained, link_self_contained_components)?;
         key!(pre_link_args_json = "pre-link-args", link_args);
         key!(late_link_args_json = "late-link-args", link_args);
         key!(late_link_args_dynamic_json = "late-link-args-dynamic", link_args);
diff --git a/compiler/rustc_target/src/spec/wasm32_wasi.rs b/compiler/rustc_target/src/spec/wasm32_wasi.rs
index 2c00c601b39..23fabcdc90d 100644
--- a/compiler/rustc_target/src/spec/wasm32_wasi.rs
+++ b/compiler/rustc_target/src/spec/wasm32_wasi.rs
@@ -73,7 +73,7 @@
 //! you know what you're getting in to!
 
 use super::crt_objects;
-use super::LinkSelfContained;
+use super::LinkSelfContainedDefault;
 use super::{wasm_base, Cc, LinkerFlavor, Target};
 
 pub fn target() -> Target {
@@ -86,7 +86,7 @@ pub fn target() -> Target {
     options.post_link_objects_self_contained = crt_objects::post_wasi_self_contained();
 
     // FIXME: Figure out cases in which WASM needs to link with a native toolchain.
-    options.link_self_contained = LinkSelfContained::True;
+    options.link_self_contained = LinkSelfContainedDefault::True;
 
     // Right now this is a bit of a workaround but we're currently saying that
     // the target by default has a static crt which we're taking as a signal
diff --git a/compiler/rustc_target/src/spec/wasm32_wasi_preview1_threads.rs b/compiler/rustc_target/src/spec/wasm32_wasi_preview1_threads.rs
index 93a49acb151..ba9a99ae380 100644
--- a/compiler/rustc_target/src/spec/wasm32_wasi_preview1_threads.rs
+++ b/compiler/rustc_target/src/spec/wasm32_wasi_preview1_threads.rs
@@ -72,9 +72,8 @@
 //! best we can with this target. Don't start relying on too much here unless
 //! you know what you're getting in to!
 
-use super::crt_objects;
-use super::LinkSelfContained;
-use super::{wasm_base, Cc, LinkerFlavor, Target};
+use super::{crt_objects, wasm_base};
+use super::{Cc, LinkSelfContainedDefault, LinkerFlavor, Target};
 
 pub fn target() -> Target {
     let mut options = wasm_base::options();
@@ -99,7 +98,7 @@ pub fn target() -> Target {
     options.post_link_objects_self_contained = crt_objects::post_wasi_self_contained();
 
     // FIXME: Figure out cases in which WASM needs to link with a native toolchain.
-    options.link_self_contained = LinkSelfContained::True;
+    options.link_self_contained = LinkSelfContainedDefault::True;
 
     // Right now this is a bit of a workaround but we're currently saying that
     // the target by default has a static crt which we're taking as a signal
diff --git a/compiler/rustc_target/src/spec/wasm_base.rs b/compiler/rustc_target/src/spec/wasm_base.rs
index a29bddd849b..82a3afeae31 100644
--- a/compiler/rustc_target/src/spec/wasm_base.rs
+++ b/compiler/rustc_target/src/spec/wasm_base.rs
@@ -1,5 +1,5 @@
+use super::LinkSelfContainedDefault;
 use super::{cvs, Cc, LinkerFlavor, PanicStrategy, RelocModel, TargetOptions, TlsModel};
-use crate::spec::LinkSelfContained;
 
 pub fn options() -> TargetOptions {
     macro_rules! args {
@@ -100,7 +100,7 @@ pub fn options() -> TargetOptions {
         // rust-lang/rust#104137: cannot blindly remove this without putting in
         // some other way to compensate for lack of `-nostartfiles` in linker
         // invocation.
-        link_self_contained: LinkSelfContained::True,
+        link_self_contained: LinkSelfContainedDefault::True,
 
         // This has no effect in LLVM 8 or prior, but in LLVM 9 and later when
         // PIC code is implemented this has quite a drastic effect if it stays
diff --git a/compiler/rustc_target/src/spec/windows_gnu_base.rs b/compiler/rustc_target/src/spec/windows_gnu_base.rs
index d99a95a77e1..b84e0fc0783 100644
--- a/compiler/rustc_target/src/spec/windows_gnu_base.rs
+++ b/compiler/rustc_target/src/spec/windows_gnu_base.rs
@@ -1,5 +1,5 @@
 use crate::spec::crt_objects;
-use crate::spec::LinkSelfContained;
+use crate::spec::LinkSelfContainedDefault;
 use crate::spec::{cvs, Cc, DebuginfoKind, LinkerFlavor, Lld, SplitDebuginfo, TargetOptions};
 use std::borrow::Cow;
 
@@ -91,7 +91,7 @@ pub fn opts() -> TargetOptions {
         post_link_objects: crt_objects::post_mingw(),
         pre_link_objects_self_contained: crt_objects::pre_mingw_self_contained(),
         post_link_objects_self_contained: crt_objects::post_mingw_self_contained(),
-        link_self_contained: LinkSelfContained::InferredForMingw,
+        link_self_contained: LinkSelfContainedDefault::InferredForMingw,
         late_link_args,
         late_link_args_dynamic,
         late_link_args_static,