port encoder.rs to SessionDiagnostics

compiler/rustc_error_messages/locales/en-US/metadata.ftl

@@ -121,3 +121,12 @@ metadata_unsupported_abi_i686 =
 
 metadata_unsupported_abi =
     ABI not supported by `#[link(kind = "raw-dylib")]` on this architecture
+
+metadata_fail_create_file_encoder =
+    failed to create file encoder: {$err}
+
+metadata_fail_seek_file =
+    failed to seek the file: {$err}
+
+metadata_fail_write_file =
+    failed to write to the file: {$err}

compiler/rustc_metadata/src/errors.rs

@@ -282,3 +282,21 @@ pub struct UnsupportedAbi {
     #[primary_span]
     pub span: Span,
 }
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::fail_create_file_encoder)]
+pub struct FailCreateFileEncoder {
+    pub err: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::fail_seek_file)]
+pub struct FailSeekFile {
+    pub err: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::fail_write_file)]
+pub struct FailWriteFile {
+    pub err: String,
+}

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1,3 +1,4 @@
+use crate::errors::{FailCreateFileEncoder, FailSeekFile, FailWriteFile};
 use crate::rmeta::def_path_hash_map::DefPathHashMapRef;
 use crate::rmeta::table::TableBuilder;
 use crate::rmeta::*;
@@ -2269,7 +2270,7 @@ pub fn encode_metadata(tcx: TyCtxt<'_>, path: &Path) {
 
 fn encode_metadata_impl(tcx: TyCtxt<'_>, path: &Path) {
     let mut encoder = opaque::FileEncoder::new(path)
-        .unwrap_or_else(|err| tcx.sess.fatal(&format!("failed to create file encoder: {}", err)));
+        .unwrap_or_else(|err| tcx.sess.emit_fatal(FailCreateFileEncoder { err: err.to_string() }));
     encoder.emit_raw_bytes(METADATA_HEADER);
 
     // Will be filled with the root position after encoding everything.
@@ -2314,10 +2315,10 @@ fn encode_metadata_impl(tcx: TyCtxt<'_>, path: &Path) {
     // Encode the root position.
     let header = METADATA_HEADER.len();
     file.seek(std::io::SeekFrom::Start(header as u64))
-        .unwrap_or_else(|err| tcx.sess.fatal(&format!("failed to seek the file: {}", err)));
+        .unwrap_or_else(|err| tcx.sess.emit_fatal(FailSeekFile { err: err.to_string() }));
     let pos = root.position.get();
     file.write_all(&[(pos >> 24) as u8, (pos >> 16) as u8, (pos >> 8) as u8, (pos >> 0) as u8])
-        .unwrap_or_else(|err| tcx.sess.fatal(&format!("failed to write to the file: {}", err)));
+        .unwrap_or_else(|err| tcx.sess.emit_fatal(FailWriteFile { err: err.to_string() }));
 
     // Return to the position where we are before writing the root position.
     file.seek(std::io::SeekFrom::Start(pos_before_seek)).unwrap();