From c26c461c0c0f4ee81616a794b1ac3cb41a3f17a6 Mon Sep 17 00:00:00 2001
From: Yoshiki Matsuda <myskjp@gmail.com>
Date: Thu, 28 Apr 2022 10:55:04 +0900
Subject: [PATCH] construct EncodedMetadata in encode_and_write_metadata

---
 compiler/rustc_metadata/src/fs.rs            | 15 +++++++++------
 compiler/rustc_metadata/src/rmeta/encoder.rs | 14 ++++++++------
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/compiler/rustc_metadata/src/fs.rs b/compiler/rustc_metadata/src/fs.rs
index 71052195fad..950009397ce 100644
--- a/compiler/rustc_metadata/src/fs.rs
+++ b/compiler/rustc_metadata/src/fs.rs
@@ -68,11 +68,9 @@ pub fn encode_and_write_metadata(
         .unwrap_or_else(|err| tcx.sess.fatal(&format!("couldn't create a temp dir: {}", err)));
     let metadata_tmpdir = MaybeTempDir::new(metadata_tmpdir, tcx.sess.opts.cg.save_temps);
     let metadata_filename = metadata_tmpdir.as_ref().join(METADATA_FILENAME);
-    let metadata = match metadata_kind {
+    match metadata_kind {
         MetadataKind::None => {
-            let metadata = EncodedMetadata::new();
-            let _ = emit_metadata(tcx.sess, metadata.raw_data(), &metadata_tmpdir);
-            metadata
+            let _ = emit_metadata(tcx.sess, &[], &metadata_tmpdir);
         }
         MetadataKind::Uncompressed | MetadataKind::Compressed => {
             encode_metadata(tcx, &metadata_filename)
@@ -82,7 +80,7 @@ pub fn encode_and_write_metadata(
     let _prof_timer = tcx.sess.prof.generic_activity("write_crate_metadata");
 
     let need_metadata_file = tcx.sess.opts.output_types.contains_key(&OutputType::Metadata);
-    if need_metadata_file {
+    let metadata_filename = if need_metadata_file {
         if let Err(e) = non_durable_rename(&metadata_filename, &out_filename) {
             tcx.sess.fatal(&format!("failed to write {}: {}", out_filename.display(), e));
         }
@@ -92,7 +90,12 @@ pub fn encode_and_write_metadata(
                 .span_diagnostic
                 .emit_artifact_notification(&out_filename, "metadata");
         }
-    }
+        out_filename
+    } else {
+        metadata_filename
+    };
+    let raw_data = std::fs::read(metadata_filename).unwrap();
+    let metadata = EncodedMetadata::from_raw_data(raw_data);
 
     let need_metadata_module = metadata_kind == MetadataKind::Compressed;
 
diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index 9ea383331b6..f18a05fcb1d 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -2146,13 +2146,18 @@ impl EncodedMetadata {
         EncodedMetadata { raw_data: Vec::new() }
     }
 
+    #[inline]
+    pub fn from_raw_data(raw_data: Vec<u8>) -> Self {
+        Self { raw_data }
+    }
+
     #[inline]
     pub fn raw_data(&self) -> &[u8] {
         &self.raw_data
     }
 }
 
-pub fn encode_metadata(tcx: TyCtxt<'_>, path: impl AsRef<Path>) -> EncodedMetadata {
+pub fn encode_metadata(tcx: TyCtxt<'_>, path: impl AsRef<Path>) {
     let _prof_timer = tcx.prof.verbose_generic_activity("generate_crate_metadata");
 
     // Since encoding metadata is not in a query, and nothing is cached,
@@ -2170,11 +2175,10 @@ pub fn encode_metadata(tcx: TyCtxt<'_>, path: impl AsRef<Path>) -> EncodedMetada
             // It can be removed if it turns out to cause trouble or be detrimental to performance.
             join(|| prefetch_mir(tcx), || tcx.exported_symbols(LOCAL_CRATE));
         },
-    )
-    .0
+    );
 }
 
-fn encode_metadata_impl(tcx: TyCtxt<'_>, path: impl AsRef<Path>) -> EncodedMetadata {
+fn encode_metadata_impl(tcx: TyCtxt<'_>, path: impl AsRef<Path>) {
     let mut encoder = opaque::FileEncoder::new(path.as_ref())
         .unwrap_or_else(|err| tcx.sess.fatal(&format!("failed to create file encoder: {}", err)));
     encoder.emit_raw_bytes(METADATA_HEADER);
@@ -2226,8 +2230,6 @@ fn encode_metadata_impl(tcx: TyCtxt<'_>, path: impl AsRef<Path>) -> EncodedMetad
 
     // Record metadata size for self-profiling
     tcx.prof.artifact_size("crate_metadata", "crate_metadata", result.len() as u64);
-
-    EncodedMetadata { raw_data: result }
 }
 
 pub fn provide(providers: &mut Providers) {