Auto merge of #95604 - nbdd0121:used2, r=petrochenkov

Generate synthetic object file to ensure all exported and used symbols participate in the linking

Fix #50007 and #47384

This is the synthetic object file approach that I described in https://github.com/rust-lang/rust/pull/95363#issuecomment-1079932354, allowing all exported and used symbols to be linked while still allowing them to be GCed.

Related #93791, #95363

r? `@petrochenkov`
cc `@carbotaniuman`

4 files changed, 9 insertions, 9 deletions

diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index 77afa7b4a5c..1edb62e189f 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -22,7 +22,7 @@ use rustc_hir::lang_items;
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_middle::arena::ArenaAllocatable;
 use rustc_middle::metadata::ModChild;
-use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportLevel};
+use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportInfo};
 use rustc_middle::middle::stability::DeprecationEntry;
 use rustc_middle::mir::interpret::{AllocDecodingSession, AllocDecodingState};
 use rustc_middle::thir;
@@ -1429,7 +1429,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     fn exported_symbols(
         self,
         tcx: TyCtxt<'tcx>,
-    ) -> &'tcx [(ExportedSymbol<'tcx>, SymbolExportLevel)] {
+    ) -> &'tcx [(ExportedSymbol<'tcx>, SymbolExportInfo)] {
         tcx.arena.alloc_from_iter(self.root.exported_symbols.decode((self, tcx)))
     }
 
diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
index 1156a78e8a9..da1dd6af65a 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -190,9 +190,9 @@ provide! { <'tcx> tcx, def_id, other, cdata,
         let reachable_non_generics = tcx
             .exported_symbols(cdata.cnum)
             .iter()
-            .filter_map(|&(exported_symbol, export_level)| {
+            .filter_map(|&(exported_symbol, export_info)| {
                 if let ExportedSymbol::NonGeneric(def_id) = exported_symbol {
-                    Some((def_id, export_level))
+                    Some((def_id, export_info))
                 } else {
                     None
                 }
diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index f485e09913e..ed49eebd16d 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -22,7 +22,7 @@ use rustc_index::vec::Idx;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::dependency_format::Linkage;
 use rustc_middle::middle::exported_symbols::{
-    metadata_symbol_name, ExportedSymbol, SymbolExportLevel,
+    metadata_symbol_name, ExportedSymbol, SymbolExportInfo,
 };
 use rustc_middle::mir::interpret;
 use rustc_middle::thir;
@@ -1874,8 +1874,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
     // definition (as that's not defined in this crate).
     fn encode_exported_symbols(
         &mut self,
-        exported_symbols: &[(ExportedSymbol<'tcx>, SymbolExportLevel)],
-    ) -> Lazy<[(ExportedSymbol<'tcx>, SymbolExportLevel)]> {
+        exported_symbols: &[(ExportedSymbol<'tcx>, SymbolExportInfo)],
+    ) -> Lazy<[(ExportedSymbol<'tcx>, SymbolExportInfo)]> {
         empty_proc_macro!(self);
         // The metadata symbol name is special. It should not show up in
         // downstream crates.
diff --git a/compiler/rustc_metadata/src/rmeta/mod.rs b/compiler/rustc_metadata/src/rmeta/mod.rs
index f1498665ff3..cdbed90e6b9 100644
--- a/compiler/rustc_metadata/src/rmeta/mod.rs
+++ b/compiler/rustc_metadata/src/rmeta/mod.rs
@@ -14,7 +14,7 @@ use rustc_hir::definitions::DefKey;
 use rustc_hir::lang_items;
 use rustc_index::{bit_set::FiniteBitSet, vec::IndexVec};
 use rustc_middle::metadata::ModChild;
-use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportLevel};
+use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportInfo};
 use rustc_middle::mir;
 use rustc_middle::thir;
 use rustc_middle::ty::fast_reject::SimplifiedType;
@@ -220,7 +220,7 @@ crate struct CrateRoot<'tcx> {
 
     tables: LazyTables<'tcx>,
 
-    exported_symbols: Lazy!([(ExportedSymbol<'tcx>, SymbolExportLevel)]),
+    exported_symbols: Lazy!([(ExportedSymbol<'tcx>, SymbolExportInfo)]),
 
     syntax_contexts: SyntaxContextTable,
     expn_data: ExpnDataTable,