Add new tool for dumping feature status based on tidy

Cargo.lock

@@ -1187,6 +1187,15 @@ version = "2.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e8c02a5121d4ea3eb16a80748c74f5549a5665e4c21333c6098f283870fbdea6"
 
+[[package]]
+name = "features-status-dump"
+version = "0.1.0"
+dependencies = [
+ "serde",
+ "serde_json",
+ "tidy",
+]
+
 [[package]]
 name = "field-offset"
 version = "0.3.6"
@@ -5249,6 +5258,7 @@ dependencies = [
  "regex",
  "rustc-hash 2.0.0",
  "semver",
+ "serde",
  "similar",
  "termcolor",
  "walkdir",

Cargo.toml

@@ -47,6 +47,7 @@ members = [
   "src/tools/coverage-dump",
   "src/tools/rustc-perf-wrapper",
   "src/tools/wasm-component-ld",
+  "src/tools/features-status-dump",
 ]
 
 exclude = [

src/tools/features-status-dump/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "features-status-dump"
+version = "0.1.0"
+license = "MIT OR Apache-2.0"
+edition = "2021"
+
+[dependencies]
+serde = { version = "1.0.125", features = [ "derive" ] }
+serde_json = "1.0.59"
+tidy = { path = "../tidy" }

src/tools/features-status-dump/src/main.rs

@@ -0,0 +1,31 @@
+use std::collections::HashMap;
+use std::env;
+use std::fs::File;
+use std::io::BufWriter;
+use std::path::Path;
+
+use tidy::features::{Feature, collect_lang_features, collect_lib_features};
+
+#[derive(serde::Serialize)]
+struct FeaturesStatus {
+    lang_features_status: HashMap<String, Feature>,
+    lib_features_status: HashMap<String, Feature>,
+}
+
+fn main() {
+    let library_path_str = env::args_os().nth(1).expect("library/ path required");
+    let compiler_path_str = env::args_os().nth(2).expect("compiler/ path required");
+    let output_path_str = env::args_os().nth(3).expect("output path required");
+    let library_path = Path::new(&library_path_str);
+    let compiler_path = Path::new(&compiler_path_str);
+    let output_path = Path::new(&output_path_str);
+    let lang_features_status = collect_lang_features(compiler_path, &mut false);
+    let lib_features_status = collect_lib_features(library_path)
+        .into_iter()
+        .filter(|&(ref name, _)| !lang_features_status.contains_key(name))
+        .collect();
+    let features_status = FeaturesStatus { lang_features_status, lib_features_status };
+    let writer = File::create(output_path).expect("output path should be a valid path");
+    let writer = BufWriter::new(writer);
+    serde_json::to_writer_pretty(writer, &features_status).unwrap();
+}

src/tools/tidy/Cargo.toml

@@ -12,6 +12,7 @@ miropt-test-tools = { path = "../miropt-test-tools" }
 walkdir = "2"
 ignore = "0.4.18"
 semver = "1.0"
+serde = { version = "1.0.125", features = [ "derive" ] }
 termcolor = "1.1.3"
 rustc-hash = "2.0.0"
 fluent-syntax = "0.11.1"

src/tools/tidy/src/features.rs

@@ -27,6 +27,7 @@ const FEATURE_GROUP_START_PREFIX: &str = "// feature-group-start";
 const FEATURE_GROUP_END_PREFIX: &str = "// feature-group-end";
 
 #[derive(Debug, PartialEq, Clone)]
+#[derive(serde::Serialize)]
 pub enum Status {
     Accepted,
     Removed,
@@ -45,6 +46,7 @@ impl fmt::Display for Status {
 }
 
 #[derive(Debug, Clone)]
+#[derive(serde::Serialize)]
 pub struct Feature {
     pub level: Status,
     pub since: Option<Version>,

src/tools/tidy/src/features/version.rs

@@ -8,6 +8,7 @@ mod tests;
 pub const VERSION_PLACEHOLDER: &str = "CURRENT_RUSTC_VERSION";
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(serde::Serialize)]
 pub enum Version {
     Explicit { parts: [u32; 3] },
     CurrentPlaceholder,