Add --print target-spec-json-schema

Cargo.lock

@@ -1133,6 +1133,12 @@ version = "1.0.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8975ffdaa0ef3661bfe02dbdcc06c9f829dfafe6a3c474de366a8d5e44276921"
 
+[[package]]
+name = "dyn-clone"
+version = "1.0.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1c7a8fb8a9fbf66c1f703fe16184d10ca0ee9d23be5b4436400408ba54a95005"
+
 [[package]]
 name = "either"
 version = "1.15.0"
@@ -3077,6 +3083,26 @@ dependencies = [
  "thiserror 2.0.12",
 ]
 
+[[package]]
+name = "ref-cast"
+version = "1.0.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4a0ae411dbe946a674d89546582cea4ba2bb8defac896622d6496f14c23ba5cf"
+dependencies = [
+ "ref-cast-impl",
+]
+
+[[package]]
+name = "ref-cast-impl"
+version = "1.0.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1165225c21bff1f3bbce98f5a1f889949bc902d3575308cc7b0de30b4f6d27c7"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.104",
+]
+
 [[package]]
 name = "regex"
 version = "1.11.1"
@@ -4563,6 +4589,7 @@ dependencies = [
  "rustc_macros",
  "rustc_serialize",
  "rustc_span",
+ "schemars",
  "serde",
  "serde_derive",
  "serde_json",
@@ -4878,6 +4905,31 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "schemars"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "82d20c4491bc164fa2f6c5d44565947a52ad80b9505d8e36f8d54c27c739fcd0"
+dependencies = [
+ "dyn-clone",
+ "ref-cast",
+ "schemars_derive",
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "schemars_derive"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "33d020396d1d138dc19f1165df7545479dcd58d93810dc5d646a16e55abefa80"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "serde_derive_internals",
+ "syn 2.0.104",
+]
+
 [[package]]
 name = "scoped-tls"
 version = "1.0.1"
@@ -4946,6 +4998,17 @@ dependencies = [
  "syn 2.0.104",
 ]
 
+[[package]]
+name = "serde_derive_internals"
+version = "0.29.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "18d26a20a969b9e3fdf2fc2d9f21eda6c40e2de84c9408bb5d3b05d499aae711"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.104",
+]
+
 [[package]]
 name = "serde_json"
 version = "1.0.141"

compiler/rustc_codegen_ssa/src/back/command.rs

@@ -109,7 +109,7 @@ impl Command {
             }
             Program::Lld(ref p, flavor) => {
                 let mut c = process::Command::new(p);
-                c.arg("-flavor").arg(flavor.as_str());
+                c.arg("-flavor").arg(flavor.desc());
                 c
             }
         };

compiler/rustc_driver_impl/src/lib.rs

@@ -667,6 +667,10 @@ fn print_crate_info(
             TargetSpecJson => {
                 println_info!("{}", serde_json::to_string_pretty(&sess.target.to_json()).unwrap());
             }
+            TargetSpecJsonSchema => {
+                let schema = rustc_target::spec::json_schema();
+                println_info!("{}", serde_json::to_string_pretty(&schema).unwrap());
+            }
             AllTargetSpecsJson => {
                 let mut targets = BTreeMap::new();
                 for name in rustc_target::spec::TARGETS {

compiler/rustc_session/src/config.rs

@@ -69,6 +69,7 @@ pub const PRINT_KINDS: &[(&str, PrintKind)] = &[
     ("target-libdir", PrintKind::TargetLibdir),
     ("target-list", PrintKind::TargetList),
     ("target-spec-json", PrintKind::TargetSpecJson),
+    ("target-spec-json-schema", PrintKind::TargetSpecJsonSchema),
     ("tls-models", PrintKind::TlsModels),
     // tidy-alphabetical-end
 ];
@@ -1052,6 +1053,7 @@ pub enum PrintKind {
     TargetLibdir,
     TargetList,
     TargetSpecJson,
+    TargetSpecJsonSchema,
     TlsModels,
     // tidy-alphabetical-end
 }
@@ -2314,7 +2316,8 @@ fn is_print_request_stable(print_kind: PrintKind) -> bool {
         | PrintKind::CheckCfg
         | PrintKind::CrateRootLintLevels
         | PrintKind::SupportedCrateTypes
-        | PrintKind::TargetSpecJson => false,
+        | PrintKind::TargetSpecJson
+        | PrintKind::TargetSpecJsonSchema => false,
         _ => true,
     }
 }

compiler/rustc_target/Cargo.toml

@@ -12,6 +12,7 @@ rustc_fs_util = { path = "../rustc_fs_util" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_span = { path = "../rustc_span" }
+schemars = "1.0.4"
 serde = "1.0.219"
 serde_derive = "1.0.219"
 serde_json = "1.0.59"

compiler/rustc_target/src/lib.rs

@@ -72,3 +72,65 @@ fn find_relative_libdir(sysroot: &Path) -> std::borrow::Cow<'static, str> {
         Some(libdir) => libdir.into(),
     }
 }
+
+macro_rules! target_spec_enum {
+    (
+        $( #[$attr:meta] )*
+        pub enum $name:ident {
+            $(
+                $( #[$variant_attr:meta] )*
+                $variant:ident = $string:literal,
+            )*
+        }
+        parse_error_type = $parse_error_type:literal;
+    ) => {
+        $( #[$attr] )*
+        #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, PartialOrd, Ord)]
+        #[derive(schemars::JsonSchema)]
+        pub enum $name {
+            $(
+                $( #[$variant_attr] )*
+                #[serde(rename = $string)] // for JSON schema generation only
+                $variant,
+            )*
+        }
+
+        impl FromStr for $name {
+            type Err = String;
+
+            fn from_str(s: &str) -> Result<Self, Self::Err> {
+                Ok(match s {
+                    $( $string => Self::$variant, )*
+                    _ => {
+                        let all = [$( concat!("'", $string, "'") ),*].join(", ");
+                        return Err(format!("invalid {}: '{s}'. allowed values: {all}", $parse_error_type));
+                    }
+                })
+            }
+        }
+
+        impl $name {
+            pub fn desc(&self) -> &'static str {
+                match self {
+                    $( Self::$variant => $string, )*
+                }
+            }
+        }
+
+        impl crate::json::ToJson for $name {
+            fn to_json(&self) -> crate::json::Json {
+                self.desc().to_json()
+            }
+        }
+
+        crate::json::serde_deserialize_from_str!($name);
+
+
+        impl std::fmt::Display for $name {
+            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+                f.write_str(self.desc())
+            }
+        }
+    };
+}
+use target_spec_enum;

compiler/rustc_target/src/spec/json.rs

@@ -413,12 +413,12 @@ impl ToJson for Target {
     }
 }
 
-#[derive(serde_derive::Deserialize)]
+#[derive(serde_derive::Deserialize, schemars::JsonSchema)]
 struct LinkSelfContainedComponentsWrapper {
     components: Vec<LinkSelfContainedComponents>,
 }
 
-#[derive(serde_derive::Deserialize)]
+#[derive(serde_derive::Deserialize, schemars::JsonSchema)]
 #[serde(untagged)]
 enum TargetFamiliesJson {
     Array(StaticCow<[StaticCow<str>]>),
@@ -434,6 +434,18 @@ impl FromStr for EndianWrapper {
     }
 }
 crate::json::serde_deserialize_from_str!(EndianWrapper);
+impl schemars::JsonSchema for EndianWrapper {
+    fn schema_name() -> std::borrow::Cow<'static, str> {
+        "Endian".into()
+    }
+    fn json_schema(_: &mut schemars::SchemaGenerator) -> schemars::Schema {
+        schemars::json_schema! ({
+            "type": "string",
+            "enum": ["big", "little"]
+        })
+        .into()
+    }
+}
 
 /// `ExternAbi` is in `rustc_abi`, which doesn't have access to the macro and serde.
 struct ExternAbiWrapper(rustc_abi::ExternAbi);
@@ -446,16 +458,30 @@ impl FromStr for ExternAbiWrapper {
     }
 }
 crate::json::serde_deserialize_from_str!(ExternAbiWrapper);
+impl schemars::JsonSchema for ExternAbiWrapper {
+    fn schema_name() -> std::borrow::Cow<'static, str> {
+        "ExternAbi".into()
+    }
+    fn json_schema(_: &mut schemars::SchemaGenerator) -> schemars::Schema {
+        let all =
+            rustc_abi::ExternAbi::ALL_VARIANTS.iter().map(|abi| abi.as_str()).collect::<Vec<_>>();
+        schemars::json_schema! ({
+            "type": "string",
+            "enum": all,
+        })
+        .into()
+    }
+}
 
-#[derive(serde_derive::Deserialize)]
+#[derive(serde_derive::Deserialize, schemars::JsonSchema)]
 struct TargetSpecJsonMetadata {
     description: Option<StaticCow<str>>,
     tier: Option<u64>,
     host_tools: Option<bool>,
     std: Option<bool>,
 }
 
-#[derive(serde_derive::Deserialize)]
+#[derive(serde_derive::Deserialize, schemars::JsonSchema)]
 #[serde(rename_all = "kebab-case")]
 // Ensure that all unexpected fields get turned into errors.
 // This helps users stay up to date when the schema changes instead of silently
@@ -598,3 +624,7 @@ struct TargetSpecJson {
     supports_xray: Option<bool>,
     entry_abi: Option<ExternAbiWrapper>,
 }
+
+pub fn json_schema() -> schemars::Schema {
+    schemars::schema_for!(TargetSpecJson)
+}