Auto merge of #85810 - bjorn3:further_driver_cleanup, r=varkor

Driver improvements

This PR contains a couple of cleanups for the driver and a few small improvements for the custom codegen backend interface. It also implements `--version` and `-Cpasses=list` support for custom codegen backends.

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -1957,7 +1957,7 @@ fn add_order_independent_options(
     cmd.output_filename(out_filename);
 
     if crate_type == CrateType::Executable && sess.target.is_like_windows {
-        if let Some(ref s) = codegen_results.windows_subsystem {
+        if let Some(ref s) = codegen_results.crate_info.windows_subsystem {
             cmd.subsystem(s);
         }
     }

compiler/rustc_codegen_ssa/src/back/symbol_export.rs

@@ -370,7 +370,6 @@ pub fn provide(providers: &mut Providers) {
 pub fn provide_extern(providers: &mut Providers) {
     providers.is_reachable_non_generic = is_reachable_non_generic_provider_extern;
     providers.upstream_monomorphizations_for = upstream_monomorphizations_for_provider;
-    providers.wasm_import_module_map = wasm_import_module_map;
 }
 
 fn symbol_export_level(tcx: TyCtxt<'_>, sym_def_id: DefId) -> SymbolExportLevel {

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -31,7 +31,7 @@ use rustc_session::config::{self, CrateType, Lto, OutputFilenames, OutputType};
 use rustc_session::config::{Passes, SwitchWithOptPath};
 use rustc_session::Session;
 use rustc_span::source_map::SourceMap;
-use rustc_span::symbol::{sym, Symbol};
+use rustc_span::symbol::sym;
 use rustc_span::{BytePos, FileName, InnerSpan, Pos, Span};
 use rustc_target::spec::{MergeFunctions, PanicStrategy, SanitizerSet};
 
@@ -426,21 +426,9 @@ pub fn start_async_codegen<B: ExtraBackendMethods>(
     let (coordinator_send, coordinator_receive) = channel();
     let sess = tcx.sess;
 
-    let crate_name = tcx.crate_name(LOCAL_CRATE);
     let crate_attrs = tcx.hir().attrs(rustc_hir::CRATE_HIR_ID);
     let no_builtins = tcx.sess.contains_name(crate_attrs, sym::no_builtins);
     let is_compiler_builtins = tcx.sess.contains_name(crate_attrs, sym::compiler_builtins);
-    let subsystem = tcx.sess.first_attr_value_str_by_name(crate_attrs, sym::windows_subsystem);
-    let windows_subsystem = subsystem.map(|subsystem| {
-        if subsystem != sym::windows && subsystem != sym::console {
-            tcx.sess.fatal(&format!(
-                "invalid windows subsystem `{}`, only \
-                                     `windows` and `console` are allowed",
-                subsystem
-            ));
-        }
-        subsystem.to_string()
-    });
 
     let linker_info = LinkerInfo::new(tcx, target_cpu);
     let crate_info = CrateInfo::new(tcx);
@@ -472,9 +460,7 @@ pub fn start_async_codegen<B: ExtraBackendMethods>(
 
     OngoingCodegen {
         backend,
-        crate_name,
         metadata,
-        windows_subsystem,
         linker_info,
         crate_info,
 
@@ -1812,9 +1798,7 @@ impl SharedEmitterMain {
 
 pub struct OngoingCodegen<B: ExtraBackendMethods> {
     pub backend: B,
-    pub crate_name: Symbol,
     pub metadata: EncodedMetadata,
-    pub windows_subsystem: Option<String>,
     pub linker_info: LinkerInfo,
     pub crate_info: CrateInfo,
     pub coordinator_send: Sender<Box<dyn Any + Send>>,
@@ -1857,9 +1841,7 @@ impl<B: ExtraBackendMethods> OngoingCodegen<B> {
 
         (
             CodegenResults {
-                crate_name: self.crate_name,
                 metadata: self.metadata,
-                windows_subsystem: self.windows_subsystem,
                 linker_info: self.linker_info,
                 crate_info: self.crate_info,
 

compiler/rustc_codegen_ssa/src/base.rs

@@ -30,6 +30,7 @@ use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
 use rustc_session::cgu_reuse_tracker::CguReuse;
 use rustc_session::config::{self, EntryFnType};
 use rustc_session::Session;
+use rustc_span::symbol::sym;
 use rustc_target::abi::{Align, LayoutOf, VariantIdx};
 
 use std::ops::{Deref, DerefMut};
@@ -755,7 +756,22 @@ impl<B: ExtraBackendMethods> Drop for AbortCodegenOnDrop<B> {
 
 impl CrateInfo {
     pub fn new(tcx: TyCtxt<'_>) -> CrateInfo {
+        let local_crate_name = tcx.crate_name(LOCAL_CRATE);
+        let crate_attrs = tcx.hir().attrs(rustc_hir::CRATE_HIR_ID);
+        let subsystem = tcx.sess.first_attr_value_str_by_name(crate_attrs, sym::windows_subsystem);
+        let windows_subsystem = subsystem.map(|subsystem| {
+            if subsystem != sym::windows && subsystem != sym::console {
+                tcx.sess.fatal(&format!(
+                    "invalid windows subsystem `{}`, only \
+                                     `windows` and `console` are allowed",
+                    subsystem
+                ));
+            }
+            subsystem.to_string()
+        });
+
         let mut info = CrateInfo {
+            local_crate_name,
             panic_runtime: None,
             compiler_builtins: None,
             profiler_runtime: None,
@@ -769,6 +785,7 @@ impl CrateInfo {
             lang_item_to_crate: Default::default(),
             missing_lang_items: Default::default(),
             dependency_formats: tcx.dependency_formats(()),
+            windows_subsystem,
         };
         let lang_items = tcx.lang_items();
 

compiler/rustc_codegen_ssa/src/lib.rs

@@ -135,6 +135,7 @@ impl From<&cstore::NativeLib> for NativeLib {
 /// and the corresponding properties without referencing information outside of a `CrateInfo`.
 #[derive(Debug, Encodable, Decodable)]
 pub struct CrateInfo {
+    pub local_crate_name: Symbol,
     pub panic_runtime: Option<CrateNum>,
     pub compiler_builtins: Option<CrateNum>,
     pub profiler_runtime: Option<CrateNum>,
@@ -148,16 +149,15 @@ pub struct CrateInfo {
     pub lang_item_to_crate: FxHashMap<LangItem, CrateNum>,
     pub missing_lang_items: FxHashMap<CrateNum, Vec<LangItem>>,
     pub dependency_formats: Lrc<Dependencies>,
+    pub windows_subsystem: Option<String>,
 }
 
 #[derive(Encodable, Decodable)]
 pub struct CodegenResults {
-    pub crate_name: Symbol,
     pub modules: Vec<CompiledModule>,
     pub allocator_module: Option<CompiledModule>,
     pub metadata_module: Option<CompiledModule>,
     pub metadata: rustc_middle::middle::cstore::EncodedMetadata,
-    pub windows_subsystem: Option<String>,
     pub linker_info: back::linker::LinkerInfo,
     pub crate_info: CrateInfo,
 }

compiler/rustc_codegen_ssa/src/traits/backend.rs

@@ -63,9 +63,16 @@ pub trait CodegenBackend {
         None
     }
 
-    fn metadata_loader(&self) -> Box<MetadataLoaderDyn>;
-    fn provide(&self, _providers: &mut Providers);
-    fn provide_extern(&self, _providers: &mut Providers);
+    /// The metadata loader used to load rlib and dylib metadata.
+    ///
+    /// Alternative codegen backends may want to use different rlib or dylib formats than the
+    /// default native static archives and dynamic libraries.
+    fn metadata_loader(&self) -> Box<MetadataLoaderDyn> {
+        Box::new(crate::back::metadata::DefaultMetadataLoader)
+    }
+
+    fn provide(&self, _providers: &mut Providers) {}
+    fn provide_extern(&self, _providers: &mut Providers) {}
     fn codegen_crate<'tcx>(
         &self,
         tcx: TyCtxt<'tcx>,