Rollup merge of #77795 - bjorn3:codegen_backend_interface_refactor, r=oli-obk

Codegen backend interface refactor

This moves several things away from the codegen backend to rustc_interface. There are a few behavioral changes where previously the incremental cache (incorrectly) wouldn't get finalized, but now it does. See the individual commit messages.

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -13,7 +13,6 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::profiling::SelfProfilerRef;
 use rustc_data_structures::profiling::TimingGuard;
 use rustc_data_structures::profiling::VerboseTimingGuard;
-use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::emitter::Emitter;
 use rustc_errors::{DiagnosticId, FatalError, Handler, Level};
@@ -414,7 +413,6 @@ pub fn start_async_codegen<B: ExtraBackendMethods>(
     let sess = tcx.sess;
 
     let crate_name = tcx.crate_name(LOCAL_CRATE);
-    let crate_hash = tcx.crate_hash(LOCAL_CRATE);
     let no_builtins = tcx.sess.contains_name(&tcx.hir().krate().item.attrs, sym::no_builtins);
     let is_compiler_builtins =
         tcx.sess.contains_name(&tcx.hir().krate().item.attrs, sym::compiler_builtins);
@@ -463,7 +461,6 @@ pub fn start_async_codegen<B: ExtraBackendMethods>(
     OngoingCodegen {
         backend,
         crate_name,
-        crate_hash,
         metadata,
         windows_subsystem,
         linker_info,
@@ -658,15 +655,6 @@ fn produce_final_output_artifacts(
     // These are used in linking steps and will be cleaned up afterward.
 }
 
-pub fn dump_incremental_data(_codegen_results: &CodegenResults) {
-    // FIXME(mw): This does not work at the moment because the situation has
-    //            become more complicated due to incremental LTO. Now a CGU
-    //            can have more than two caching states.
-    // println!("[incremental] Re-using {} out of {} modules",
-    //           codegen_results.modules.iter().filter(|m| m.pre_existing).count(),
-    //           codegen_results.modules.len());
-}
-
 pub enum WorkItem<B: WriteBackendMethods> {
     /// Optimize a newly codegened, totally unoptimized module.
     Optimize(ModuleCodegen<B::Module>),
@@ -1720,7 +1708,6 @@ impl SharedEmitterMain {
 pub struct OngoingCodegen<B: ExtraBackendMethods> {
     pub backend: B,
     pub crate_name: Symbol,
-    pub crate_hash: Svh,
     pub metadata: EncodedMetadata,
     pub windows_subsystem: Option<String>,
     pub linker_info: LinkerInfo,
@@ -1766,7 +1753,6 @@ impl<B: ExtraBackendMethods> OngoingCodegen<B> {
         (
             CodegenResults {
                 crate_name: self.crate_name,
-                crate_hash: self.crate_hash,
                 metadata: self.metadata,
                 windows_subsystem: self.windows_subsystem,
                 linker_info: self.linker_info,

compiler/rustc_codegen_ssa/src/lib.rs

@@ -21,7 +21,6 @@ extern crate tracing;
 extern crate rustc_middle;
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::Lrc;
 use rustc_hir::def_id::CrateNum;
 use rustc_hir::LangItem;
@@ -134,7 +133,6 @@ pub struct CodegenResults {
     pub modules: Vec<CompiledModule>,
     pub allocator_module: Option<CompiledModule>,
     pub metadata_module: Option<CompiledModule>,
-    pub crate_hash: Svh,
     pub metadata: rustc_middle::middle::cstore::EncodedMetadata,
     pub windows_subsystem: Option<String>,
     pub linker_info: back::linker::LinkerInfo,
@@ -144,6 +142,7 @@ pub struct CodegenResults {
 pub fn provide(providers: &mut Providers) {
     crate::back::symbol_export::provide(providers);
     crate::base::provide_both(providers);
+    crate::target_features::provide(providers);
 }
 
 pub fn provide_extern(providers: &mut Providers) {

compiler/rustc_codegen_ssa/src/target_features.rs

@@ -1,3 +1,5 @@
+use rustc_hir::def_id::LOCAL_CRATE;
+use rustc_middle::ty::query::Providers;
 use rustc_session::Session;
 use rustc_span::symbol::sym;
 use rustc_span::symbol::Symbol;
@@ -148,3 +150,16 @@ pub fn supported_target_features(sess: &Session) -> &'static [(&'static str, Opt
         _ => &[],
     }
 }
+
+pub(crate) fn provide(providers: &mut Providers) {
+    providers.supported_target_features = |tcx, cnum| {
+        assert_eq!(cnum, LOCAL_CRATE);
+        if tcx.sess.opts.actually_rustdoc {
+            // rustdoc needs to be able to document functions that use all the features, so
+            // whitelist them all
+            all_known_features().map(|(a, b)| (a.to_string(), b)).collect()
+        } else {
+            supported_target_features(tcx.sess).iter().map(|&(a, b)| (a.to_string(), b)).collect()
+        }
+    };
+}

compiler/rustc_codegen_ssa/src/traits/backend.rs

@@ -1,10 +1,11 @@
 use super::write::WriteBackendMethods;
 use super::CodegenObject;
-use crate::ModuleCodegen;
+use crate::{CodegenResults, ModuleCodegen};
 
 use rustc_ast::expand::allocator::AllocatorKind;
+use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::ErrorReported;
-use rustc_middle::dep_graph::DepGraph;
+use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_middle::middle::cstore::{EncodedMetadata, MetadataLoaderDyn};
 use rustc_middle::ty::layout::{HasTyCtxt, TyAndLayout};
 use rustc_middle::ty::query::Providers;
@@ -80,8 +81,7 @@ pub trait CodegenBackend {
         &self,
         ongoing_codegen: Box<dyn Any>,
         sess: &Session,
-        dep_graph: &DepGraph,
-    ) -> Result<Box<dyn Any>, ErrorReported>;
+    ) -> Result<(CodegenResults, FxHashMap<WorkProductId, WorkProduct>), ErrorReported>;
 
     /// This is called on the returned `Box<dyn Any>` from `join_codegen`
     ///
@@ -91,7 +91,7 @@ pub trait CodegenBackend {
     fn link(
         &self,
         sess: &Session,
-        codegen_results: Box<dyn Any>,
+        codegen_results: CodegenResults,
         outputs: &OutputFilenames,
     ) -> Result<(), ErrorReported>;
 }