Rollup merge of #69965 - mark-i-m:codegen-utils, r=eddyb

Refactorings to get rid of rustc_codegen_utils

r? @eddyb

cc #45276

After this, the only modules left in `rustc_codegen_utils` are
- `link`: a bunch of linking-related functions (many dealing with file names). These are mostly consumed by save analysis, rustc_driver, rustc_interface, and of course codegen. I assume they live here because we don't want a dependency of save analysis on codegen... Perhaps they can be moved to librustc?
- ~`symbol_names` and `symbol_names_test`: honestly it seems odd that `symbol_names_test` is not a submodule of `symbol_names`. It seems like these could honestly live in their own crate or move to librustc. Already name mangling is exported as the `symbol_name` query.~ (move it to its own crate)

I don't mind doing either of the above as part of this PR or a followup if you want.

6 files changed, 76 insertions, 24 deletions

diff --git a/src/librustc_codegen_ssa/Cargo.toml b/src/librustc_codegen_ssa/Cargo.toml
index 3181d568b01..299f4d2c669 100644
--- a/src/librustc_codegen_ssa/Cargo.toml
+++ b/src/librustc_codegen_ssa/Cargo.toml
@@ -25,7 +25,7 @@ rustc_span = { path = "../librustc_span" }
 rustc = { path = "../librustc" }
 rustc_apfloat = { path = "../librustc_apfloat" }
 rustc_attr = { path = "../librustc_attr" }
-rustc_codegen_utils = { path = "../librustc_codegen_utils" }
+rustc_symbol_mangling = { path = "../librustc_symbol_mangling" }
 rustc_data_structures = { path = "../librustc_data_structures"}
 rustc_errors = { path = "../librustc_errors" }
 rustc_fs_util = { path = "../librustc_fs_util" }
@@ -34,3 +34,4 @@ rustc_incremental = { path = "../librustc_incremental" }
 rustc_index = { path = "../librustc_index" }
 rustc_target = { path = "../librustc_target" }
 rustc_session = { path = "../librustc_session" }
+rustc_metadata = { path = "../librustc_metadata" }
diff --git a/src/librustc_codegen_ssa/back/link.rs b/src/librustc_codegen_ssa/back/link.rs
index af413d3cdfe..672b6e4aa46 100644
--- a/src/librustc_codegen_ssa/back/link.rs
+++ b/src/librustc_codegen_ssa/back/link.rs
@@ -6,6 +6,7 @@ use rustc_hir::def_id::CrateNum;
 use rustc_session::config::{
     self, CFGuard, DebugInfo, OutputFilenames, OutputType, PrintRequest, Sanitizer,
 };
+use rustc_session::output::{check_file_is_writeable, invalid_output_for_target, out_filename};
 use rustc_session::search_paths::PathKind;
 /// For all the linkers we support, and information they might
 /// need out of the shared crate context before we get rid of it.
@@ -36,8 +37,6 @@ use std::path::{Path, PathBuf};
 use std::process::{ExitStatus, Output, Stdio};
 use std::str;
 
-pub use rustc_codegen_utils::link::*;
-
 pub fn remove(sess: &Session, path: &Path) {
     if let Err(e) = fs::remove_file(path) {
         sess.err(&format!("failed to remove {}: {}", path.display(), e));
diff --git a/src/librustc_codegen_ssa/back/symbol_export.rs b/src/librustc_codegen_ssa/back/symbol_export.rs
index 8368d98884a..8a2503ce167 100644
--- a/src/librustc_codegen_ssa/back/symbol_export.rs
+++ b/src/librustc_codegen_ssa/back/symbol_export.rs
@@ -8,7 +8,6 @@ use rustc::ty::subst::{GenericArgKind, SubstsRef};
 use rustc::ty::Instance;
 use rustc::ty::{SymbolName, TyCtxt};
 use rustc_ast::expand::allocator::ALLOCATOR_METHODS;
-use rustc_codegen_utils::symbol_names;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir as hir;
@@ -423,17 +422,21 @@ pub fn symbol_name_for_instance_in_crate<'tcx>(
     // This is something instantiated in an upstream crate, so we have to use
     // the slower (because uncached) version of computing the symbol name.
     match symbol {
-        ExportedSymbol::NonGeneric(def_id) => symbol_names::symbol_name_for_instance_in_crate(
-            tcx,
-            Instance::mono(tcx, def_id),
-            instantiating_crate,
-        ),
-        ExportedSymbol::Generic(def_id, substs) => symbol_names::symbol_name_for_instance_in_crate(
-            tcx,
-            Instance::new(def_id, substs),
-            instantiating_crate,
-        ),
-        ExportedSymbol::DropGlue(ty) => symbol_names::symbol_name_for_instance_in_crate(
+        ExportedSymbol::NonGeneric(def_id) => {
+            rustc_symbol_mangling::symbol_name_for_instance_in_crate(
+                tcx,
+                Instance::mono(tcx, def_id),
+                instantiating_crate,
+            )
+        }
+        ExportedSymbol::Generic(def_id, substs) => {
+            rustc_symbol_mangling::symbol_name_for_instance_in_crate(
+                tcx,
+                Instance::new(def_id, substs),
+                instantiating_crate,
+            )
+        }
+        ExportedSymbol::DropGlue(ty) => rustc_symbol_mangling::symbol_name_for_instance_in_crate(
             tcx,
             Instance::resolve_drop_in_place(tcx, ty),
             instantiating_crate,
diff --git a/src/librustc_codegen_ssa/base.rs b/src/librustc_codegen_ssa/base.rs
index 5fd16cb121f..834702a3009 100644
--- a/src/librustc_codegen_ssa/base.rs
+++ b/src/librustc_codegen_ssa/base.rs
@@ -36,7 +36,6 @@ use rustc::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
 use rustc::ty::query::Providers;
 use rustc::ty::{self, Instance, Ty, TyCtxt};
 use rustc_attr as attr;
-use rustc_codegen_utils::{check_for_rustc_errors_attr, symbol_names_test};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::profiling::print_time_passes_entry;
 use rustc_data_structures::sync::{par_iter, Lock, ParallelIterator};
@@ -47,6 +46,7 @@ use rustc_session::cgu_reuse_tracker::CguReuse;
 use rustc_session::config::{self, EntryFnType, Lto};
 use rustc_session::Session;
 use rustc_span::Span;
+use rustc_symbol_mangling::test as symbol_names_test;
 
 use std::cmp;
 use std::ops::{Deref, DerefMut};
@@ -514,8 +514,6 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
     metadata: EncodedMetadata,
     need_metadata_module: bool,
 ) -> OngoingCodegen<B> {
-    check_for_rustc_errors_attr(tcx);
-
     // Skip crate items and just output metadata in -Z no-codegen mode.
     if tcx.sess.opts.debugging_opts.no_codegen || !tcx.sess.opts.output_types.should_codegen() {
         let ongoing_codegen = start_async_codegen(backend, tcx, metadata, 1);
diff --git a/src/librustc_codegen_ssa/traits/backend.rs b/src/librustc_codegen_ssa/traits/backend.rs
index 7acae300a2f..4e861f45ff7 100644
--- a/src/librustc_codegen_ssa/traits/backend.rs
+++ b/src/librustc_codegen_ssa/traits/backend.rs
@@ -2,15 +2,22 @@ use super::write::WriteBackendMethods;
 use super::CodegenObject;
 use crate::ModuleCodegen;
 
-use rustc::middle::cstore::EncodedMetadata;
+use rustc::dep_graph::DepGraph;
+use rustc::middle::cstore::{EncodedMetadata, MetadataLoaderDyn};
 use rustc::ty::layout::{HasTyCtxt, LayoutOf, TyLayout};
-use rustc::ty::Ty;
-use rustc::ty::TyCtxt;
+use rustc::ty::query::Providers;
+use rustc::ty::{Ty, TyCtxt};
+use rustc::util::common::ErrorReported;
 use rustc_ast::expand::allocator::AllocatorKind;
-use rustc_codegen_utils::codegen_backend::CodegenBackend;
-use rustc_session::{config, Session};
+use rustc_session::{
+    config::{self, OutputFilenames, PrintRequest},
+    Session,
+};
 use rustc_span::symbol::Symbol;
 
+pub use rustc_data_structures::sync::MetadataRef;
+
+use std::any::Any;
 use std::sync::Arc;
 
 pub trait BackendTypes {
@@ -37,6 +44,50 @@ impl<'tcx, T> Backend<'tcx> for T where
 {
 }
 
+pub trait CodegenBackend {
+    fn init(&self, _sess: &Session) {}
+    fn print(&self, _req: PrintRequest, _sess: &Session) {}
+    fn target_features(&self, _sess: &Session) -> Vec<Symbol> {
+        vec![]
+    }
+    fn print_passes(&self) {}
+    fn print_version(&self) {}
+
+    fn metadata_loader(&self) -> Box<MetadataLoaderDyn>;
+    fn provide(&self, _providers: &mut Providers<'_>);
+    fn provide_extern(&self, _providers: &mut Providers<'_>);
+    fn codegen_crate<'tcx>(
+        &self,
+        tcx: TyCtxt<'tcx>,
+        metadata: EncodedMetadata,
+        need_metadata_module: bool,
+    ) -> Box<dyn Any>;
+
+    /// This is called on the returned `Box<dyn Any>` from `codegen_backend`
+    ///
+    /// # Panics
+    ///
+    /// Panics when the passed `Box<dyn Any>` was not returned by `codegen_backend`.
+    fn join_codegen(
+        &self,
+        ongoing_codegen: Box<dyn Any>,
+        sess: &Session,
+        dep_graph: &DepGraph,
+    ) -> Result<Box<dyn Any>, ErrorReported>;
+
+    /// This is called on the returned `Box<dyn Any>` from `join_codegen`
+    ///
+    /// # Panics
+    ///
+    /// Panics when the passed `Box<dyn Any>` was not returned by `join_codegen`.
+    fn link(
+        &self,
+        sess: &Session,
+        codegen_results: Box<dyn Any>,
+        outputs: &OutputFilenames,
+    ) -> Result<(), ErrorReported>;
+}
+
 pub trait ExtraBackendMethods: CodegenBackend + WriteBackendMethods + Sized + Send + Sync {
     fn new_metadata(&self, sess: TyCtxt<'_>, mod_name: &str) -> Self::Module;
     fn write_compressed_metadata<'tcx>(
diff --git a/src/librustc_codegen_ssa/traits/mod.rs b/src/librustc_codegen_ssa/traits/mod.rs
index d03ff8d4d37..1bc9f297ea1 100644
--- a/src/librustc_codegen_ssa/traits/mod.rs
+++ b/src/librustc_codegen_ssa/traits/mod.rs
@@ -29,7 +29,7 @@ mod write;
 
 pub use self::abi::AbiBuilderMethods;
 pub use self::asm::{AsmBuilderMethods, AsmMethods};
-pub use self::backend::{Backend, BackendTypes, ExtraBackendMethods};
+pub use self::backend::{Backend, BackendTypes, CodegenBackend, ExtraBackendMethods};
 pub use self::builder::{BuilderMethods, OverflowOp};
 pub use self::consts::ConstMethods;
 pub use self::debuginfo::{DebugInfoBuilderMethods, DebugInfoMethods};