Replace spaghetti with a simple errors enum

compiler/rustc_codegen_ssa/src/lib.rs

@@ -21,7 +21,6 @@ extern crate tracing;
 #[macro_use]
 extern crate rustc_middle;
 
-use crate::session_diagnostic::{DeserializeRlinkError, DeserializeRlinkErrorSub};
 use rustc_ast as ast;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::sync::Lrc;
@@ -50,7 +49,6 @@ pub mod glue;
 pub mod meth;
 pub mod mir;
 pub mod mono_item;
-pub mod session_diagnostic;
 pub mod target_features;
 pub mod traits;
 
@@ -170,6 +168,13 @@ pub struct CodegenResults {
     pub crate_info: CrateInfo,
 }
 
+pub enum CodegenErrors {
+    WrongFileType,
+    EmptyVersionNumber,
+    EncodingVersionMismatch { version_array: String, rlink_version: String },
+    RustcVersionMismatch { rustc_version: String, current_version: String },
+}
+
 pub fn provide(providers: &mut Providers) {
     crate::back::symbol_export::provide(providers);
     crate::base::provide(providers);
@@ -214,27 +219,23 @@ impl CodegenResults {
         encoder.finish()
     }
 
-    pub fn deserialize_rlink(data: Vec<u8>) -> Result<Self, DeserializeRlinkError> {
+    pub fn deserialize_rlink(data: Vec<u8>) -> Result<Self, CodegenErrors> {
         // The Decodable machinery is not used here because it panics if the input data is invalid
         // and because its internal representation may change.
         if !data.starts_with(RLINK_MAGIC) {
-            return Err(DeserializeRlinkError { sub: DeserializeRlinkErrorSub::WrongFileType });
+            return Err(CodegenErrors::WrongFileType);
         }
         let data = &data[RLINK_MAGIC.len()..];
         if data.len() < 4 {
-            return Err(DeserializeRlinkError {
+            return Err(CodegenErrors::EmptyVersionNumber);
-                sub: DeserializeRlinkErrorSub::EmptyVersionNumber,
-            });
         }
 
         let mut version_array: [u8; 4] = Default::default();
         version_array.copy_from_slice(&data[..4]);
         if u32::from_be_bytes(version_array) != RLINK_VERSION {
-            return Err(DeserializeRlinkError {
+            return Err(CodegenErrors::EncodingVersionMismatch {
-                sub: DeserializeRlinkErrorSub::EncodingVersionMismatch {
                 version_array: String::from_utf8_lossy(&version_array).to_string(),
                 rlink_version: RLINK_VERSION.to_string(),
-                },
             });
         }
 
@@ -242,11 +243,9 @@ impl CodegenResults {
         let rustc_version = decoder.read_str();
         let current_version = RUSTC_VERSION.unwrap();
         if rustc_version != current_version {
-            return Err(DeserializeRlinkError {
+            return Err(CodegenErrors::RustcVersionMismatch {
-                sub: DeserializeRlinkErrorSub::RustcVersionMismatch {
                 rustc_version: rustc_version.to_string(),
                 current_version: current_version.to_string(),
-                },
             });
         }
 

compiler/rustc_codegen_ssa/src/session_diagnostic.rs

@@ -1,42 +0,0 @@
-use rustc_errors::{fluent, DiagnosticArgValue, IntoDiagnosticArg};
-use rustc_macros::{SessionDiagnostic, SessionSubdiagnostic};
-use std::borrow::Cow;
-
-#[derive(SessionDiagnostic)]
-#[diag(codegen_ssa::error)]
-pub struct DeserializeRlinkError {
-    #[subdiagnostic]
-    pub sub: DeserializeRlinkErrorSub,
-}
-
-#[derive(SessionSubdiagnostic)]
-pub enum DeserializeRlinkErrorSub {
-    #[note(codegen_ssa::wrong_file_type)]
-    WrongFileType,
-
-    #[note(codegen_ssa::empty_version_number)]
-    EmptyVersionNumber,
-
-    #[note(codegen_ssa::encoding_version_mismatch)]
-    EncodingVersionMismatch { version_array: String, rlink_version: String },
-
-    #[note(codegen_ssa::rustc_version_mismatch)]
-    RustcVersionMismatch { rustc_version: String, current_version: String },
-}
-
-impl IntoDiagnosticArg for DeserializeRlinkErrorSub {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Borrowed(match self {
-            DeserializeRlinkErrorSub::WrongFileType => fluent::codegen_ssa::wrong_file_type,
-            DeserializeRlinkErrorSub::EmptyVersionNumber => {
-                fluent::codegen_ssa::empty_version_number
-            }
-            DeserializeRlinkErrorSub::EncodingVersionMismatch { version_array, rlink_version } => {
-                fluent::codegen_ssa::encoding_version_mismatch
-            }
-            DeserializeRlinkErrorSub::RustcVersionMismatch { rustc_version, current_version } => {
-                fluent::codegen_ssa::rustc_version_mismatch
-            }
-        }))
-    }
-}

compiler/rustc_driver/src/lib.rs

@@ -18,7 +18,7 @@ extern crate tracing;
 pub extern crate rustc_plugin_impl as plugin;
 
 use rustc_ast as ast;
-use rustc_codegen_ssa::{traits::CodegenBackend, CodegenResults};
+use rustc_codegen_ssa::{traits::CodegenBackend, CodegenErrors, CodegenResults};
 use rustc_data_structures::profiling::{get_resident_set_size, print_time_passes_entry};
 use rustc_data_structures::sync::SeqCst;
 use rustc_errors::registry::{InvalidErrorCode, Registry};
@@ -60,7 +60,10 @@ pub mod args;
 pub mod pretty;
 mod session_diagnostics;
 
-use crate::session_diagnostics::{RlinkNotAFile, RlinkUnableToDeserialize, RlinkUnableToRead};
+use crate::session_diagnostics::{
+    RLinkEmptyVersionNumber, RLinkEncodingVersionMismatch, RLinkRustcVersionMismatch,
+    RLinkWrongFileType, RlinkNotAFile, RlinkUnableToRead,
+};
 
 /// Exit status code used for successful compilation and help output.
 pub const EXIT_SUCCESS: i32 = 0;
@@ -591,7 +594,24 @@ pub fn try_process_rlink(sess: &Session, compiler: &interface::Compiler) -> Comp
             let codegen_results = match CodegenResults::deserialize_rlink(rlink_data) {
                 Ok(codegen) => codegen,
                 Err(err) => {
-                    sess.emit_fatal(RlinkUnableToDeserialize { err });
+                    match err {
+                        CodegenErrors::WrongFileType => sess.emit_fatal(RLinkWrongFileType),
+                        CodegenErrors::EmptyVersionNumber => {
+                            sess.emit_fatal(RLinkEmptyVersionNumber)
+                        }
+                        CodegenErrors::EncodingVersionMismatch { version_array, rlink_version } => {
+                            sess.emit_fatal(RLinkEncodingVersionMismatch {
+                                version_array,
+                                rlink_version,
+                            })
+                        }
+                        CodegenErrors::RustcVersionMismatch { rustc_version, current_version } => {
+                            sess.emit_fatal(RLinkRustcVersionMismatch {
+                                rustc_version,
+                                current_version,
+                            })
+                        }
+                    };
                 }
             };
             let result = compiler.codegen_backend().link(sess, codegen_results, &outputs);

compiler/rustc_driver/src/session_diagnostics.rs

@@ -1,4 +1,3 @@
-use rustc_codegen_ssa::session_diagnostic::DeserializeRlinkError;
 use rustc_macros::SessionDiagnostic;
 
 #[derive(SessionDiagnostic)]
@@ -8,9 +7,25 @@ pub(crate) struct RlinkUnableToRead {
 }
 
 #[derive(SessionDiagnostic)]
-#[diag(driver::rlink_unable_to_deserialize)]
+#[diag(driver::rlink_wrong_file_type)]
-pub(crate) struct RlinkUnableToDeserialize {
+pub(crate) struct RLinkWrongFileType;
-    pub err: DeserializeRlinkError,
+
+#[derive(SessionDiagnostic)]
+#[diag(driver::rlink_empty_version_number)]
+pub(crate) struct RLinkEmptyVersionNumber;
+
+#[derive(SessionDiagnostic)]
+#[diag(driver::rlink_encoding_version_mismatch)]
+pub(crate) struct RLinkEncodingVersionMismatch {
+    pub version_array: String,
+    pub rlink_version: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(driver::rlink_rustc_version_mismatch)]
+pub(crate) struct RLinkRustcVersionMismatch {
+    pub rustc_version: String,
+    pub current_version: String,
 }
 
 #[derive(SessionDiagnostic)]

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

@@ -1,9 +0,0 @@
-codegen_ssa_error = Error while deserializing rlink file
-
-codegen_ssa_wrong_file_type = The input does not look like a .rlink file
-
-codegen_ssa_empty_version_number = The input does not contain version number
-
-codegen_ssa_encoding_version_mismatch = .rlink file was produced with encoding version `{$version_array}`, but the current version is `{$rlink_version}`
-
-codegen_ssa_rustc_version_mismatch = .rlink file was produced by rustc version `{$rustc_version}`, but the current version is `{$current_version}`

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

@@ -1,5 +1,11 @@
 driver_rlink_unable_to_read = failed to read rlink file: `{$err}`
 
-driver_rlink_unable_to_deserialize = could not deserialize .rlink file: `{$error_message}`
+driver_rlink_wrong_file_type = The input does not look like a .rlink file
+
+driver_rlink_empty_version_number = The input does not contain version number
+
+driver_rlink_encoding_version_mismatch = .rlink file was produced with encoding version `{$version_array}`, but the current version is `{$rlink_version}`
+
+driver_rlink_rustc_version_mismatch = .rlink file was produced by rustc version `{$rustc_version}`, but the current version is `{$current_version}`
 
 driver_rlink_no_a_file = rlink must be a file

compiler/rustc_error_messages/src/lib.rs

@@ -35,7 +35,6 @@ fluent_messages! {
     ast_passes => "../locales/en-US/ast_passes.ftl",
     borrowck => "../locales/en-US/borrowck.ftl",
     builtin_macros => "../locales/en-US/builtin_macros.ftl",
-    codegen_ssa => "../locales/en-US/codegen_ssa.ftl",
     const_eval => "../locales/en-US/const_eval.ftl",
     driver => "../locales/en-US/driver.ftl",
     expand => "../locales/en-US/expand.ftl",