Add --print target-spec-json-schema

This schema is helpful for people writing custom target spec JSON. It
can provide autocomplete in the editor, and also serves as documentation
when there are documentation comments on the structs, as `schemars` will
put them in the schema.

1 files changed, 2 insertions, 0 deletions

diff --git a/compiler/rustc_target/src/lib.rs b/compiler/rustc_target/src/lib.rs
index c6a23745b04..b3fe1fffcce 100644
--- a/compiler/rustc_target/src/lib.rs
+++ b/compiler/rustc_target/src/lib.rs
@@ -86,9 +86,11 @@ macro_rules! target_spec_enum {
     ) => {
         $( #[$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,
             )*
         }