refactor encode_and_write_metadata

Author: m-ysk

compiler/rustc_metadata/src/fs.rs

@@ -68,53 +68,45 @@ 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 need_metadata_file = tcx.sess.opts.output_types.contains_key(&OutputType::Metadata);
-    let metadata = match metadata_kind {
+
+    match metadata_kind {
         MetadataKind::None => {
-            if need_metadata_file {
-                // Though creating the empty file here seems to be meaningless, cargo expects it.
-                if let Err(e) = std::fs::File::create(&out_filename) {
-                    tcx.sess.fatal(&format!(
-                        "failed to create the file {}: {}",
-                        out_filename.display(),
-                        e
-                    ));
-                }
-                if tcx.sess.opts.json_artifact_notifications {
-                    tcx.sess
-                        .parse_sess
-                        .span_diagnostic
-                        .emit_artifact_notification(&out_filename, "metadata");
-                }
-            }
-            EncodedMetadata::empty()
+            std::fs::File::create(&metadata_filename).unwrap_or_else(|e| {
+                tcx.sess.fatal(&format!(
+                    "failed to create the file {}: {}",
+                    out_filename.display(),
+                    e
+                ))
+            });
         }
         MetadataKind::Uncompressed | MetadataKind::Compressed => {
             encode_metadata(tcx, &metadata_filename);
+        }
+    };
 
-            let _prof_timer = tcx.sess.prof.generic_activity("write_crate_metadata");
-
-            let (metadata_filename, metadata_tmpdir) = 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));
-                }
-                if tcx.sess.opts.json_artifact_notifications {
-                    tcx.sess
-                        .parse_sess
-                        .span_diagnostic
-                        .emit_artifact_notification(&out_filename, "metadata");
-                }
-                (out_filename, None)
-            } else {
-                (metadata_filename, Some(metadata_tmpdir))
-            };
-
-            EncodedMetadata::from_path(metadata_filename, metadata_tmpdir).unwrap_or_else(|e| {
-                tcx.sess.fatal(&format!("failed to create encoded metadata from file: {}", e))
-            })
+    let _prof_timer = tcx.sess.prof.generic_activity("write_crate_metadata");
+
+    let need_metadata_file = tcx.sess.opts.output_types.contains_key(&OutputType::Metadata);
+    let (metadata_filename, metadata_tmpdir) = 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));
         }
+        if tcx.sess.opts.json_artifact_notifications {
+            tcx.sess
+                .parse_sess
+                .span_diagnostic
+                .emit_artifact_notification(&out_filename, "metadata");
+        }
+        (out_filename, None)
+    } else {
+        (metadata_filename, Some(metadata_tmpdir))
     };
 
+    let metadata =
+        EncodedMetadata::from_path(metadata_filename, metadata_tmpdir).unwrap_or_else(|e| {
+            tcx.sess.fatal(&format!("failed to create encoded metadata from file: {}", e))
+        });
+
     let need_metadata_module = metadata_kind == MetadataKind::Compressed;
 
     (metadata, need_metadata_module)

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -2163,11 +2163,6 @@ impl EncodedMetadata {
         Ok(Self { mmap, _temp_dir: temp_dir })
     }
 
-    #[inline]
-    pub fn empty() -> Self {
-        Self { mmap: None, _temp_dir: None }
-    }
-
     #[inline]
     pub fn raw_data(&self) -> &[u8] {
         self.mmap.as_ref().map(|mmap| mmap.as_ref()).unwrap_or_default()