Auto merge of #113382 - lqd:test-mcp510, r=<try>

[perf] test MCP510 r? `@ghost`
rust-lang · Sep 6, 2024 · 8303600 · 8303600
2 parents d678b81 + 3fcb375
commit 8303600
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Showing 3 changed files with 38 additions and 18 deletions.
diff --git a/compiler/rustc_codegen_gcc/src/allocator.rs b/compiler/rustc_codegen_gcc/src/allocator.rs
@@ -107,6 +107,9 @@ fn create_wrapper_function(
     if tcx.sess.default_hidden_visibility() {
         #[cfg(feature = "master")]
         func.add_attribute(FnAttribute::Visibility(gccjit::Visibility::Hidden));
+    } else {
+        #[cfg(feature = "master")]
+        func.add_attribute(FnAttribute::Visibility(gccjit::Visibility::Protected));
     }
     if tcx.sess.must_emit_unwind_tables() {
         // TODO(antoyo): emit unwind tables.

diff --git a/compiler/rustc_codegen_llvm/src/allocator.rs b/compiler/rustc_codegen_llvm/src/allocator.rs
@@ -79,6 +79,8 @@ pub(crate) unsafe fn codegen(
         let ll_g = llvm::LLVMRustGetOrInsertGlobal(llmod, name.as_ptr().cast(), name.len(), i8);
         if tcx.sess.default_hidden_visibility() {
             llvm::LLVMRustSetVisibility(ll_g, llvm::Visibility::Hidden);
+        } else {
+            llvm::LLVMRustSetVisibility(ll_g, llvm::Visibility::Protected);
         }
         let val = tcx.sess.opts.unstable_opts.oom.should_panic();
         let llval = llvm::LLVMConstInt(i8, val as u64, False);
@@ -88,6 +90,8 @@ pub(crate) unsafe fn codegen(
         let ll_g = llvm::LLVMRustGetOrInsertGlobal(llmod, name.as_ptr().cast(), name.len(), i8);
         if tcx.sess.default_hidden_visibility() {
             llvm::LLVMRustSetVisibility(ll_g, llvm::Visibility::Hidden);
+        } else {
+            llvm::LLVMRustSetVisibility(ll_g, llvm::Visibility::Protected);
         }
         let llval = llvm::LLVMConstInt(i8, 0, False);
         llvm::LLVMSetInitializer(ll_g, llval);
@@ -134,6 +138,8 @@ fn create_wrapper_function(
 
         if tcx.sess.default_hidden_visibility() {
             llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden);
+        } else {
+            llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Protected);
         }
         if tcx.sess.must_emit_unwind_tables() {
             let uwtable =

diff --git a/compiler/rustc_monomorphize/src/partitioning.rs b/compiler/rustc_monomorphize/src/partitioning.rs
@@ -902,26 +902,37 @@ fn mono_item_visibility<'tcx>(
 }
 
 fn default_visibility(tcx: TyCtxt<'_>, id: DefId, is_generic: bool) -> Visibility {
-    if !tcx.sess.default_hidden_visibility() {
-        return Visibility::Default;
-    }
+    let export_level = if is_generic {
+        // Generic functions never have export-level C.
+        SymbolExportLevel::Rust
+    } else if !id.is_local() {
+        // Things with export level C don't get instantiated in
+        // downstream crates.
+        SymbolExportLevel::Rust
+    } else {
+        match tcx.reachable_non_generics(id.krate).get(&id) {
+            Some(SymbolExportInfo { level: SymbolExportLevel::C, .. }) => SymbolExportLevel::C,
+            _ => SymbolExportLevel::Rust,
+        }
+    };
 
-    // Generic functions never have export-level C.
-    if is_generic {
-        return Visibility::Hidden;
-    }
+    match export_level {
+        // C-export level items remain at `Default` to allow C code to
+        // access and interpose them.
+        SymbolExportLevel::C => Visibility::Default,
 
-    // Things with export level C don't get instantiated in
-    // downstream crates.
-    if !id.is_local() {
-        return Visibility::Hidden;
-    }
-
-    // C-export level items remain at `Default`, all other internal
-    // items become `Hidden`.
-    match tcx.reachable_non_generics(id.krate).get(&id) {
-        Some(SymbolExportInfo { level: SymbolExportLevel::C, .. }) => Visibility::Default,
-        _ => Visibility::Hidden,
+        // All other items become `Hidden` or `Protected` depending on
+        // `default_hidden_visibility`.
+        SymbolExportLevel::Rust => {
+            if tcx.sess.target.default_hidden_visibility {
+                Visibility::Hidden
+            } else {
+                // Items with mangled symbols don't have a predictable name,
+                // so no dylib that doesn't depend on compiler internals can
+                // do interposition on rust items.
+                Visibility::Protected
+            }
+        }
     }
 }