Auto merge of #99944 - bjorn3:hide_proc_macro_symbols, r=eddyb

Limit symbols exported from proc macros

Only `__rustc_proc_macro_decls_*__` and `rust_metadata_*` need to be
exported for proc macros to work. All other symbols only increase binary
size and have the potential to conflict with symbols from the host
compiler.

Fixes https://github.com/rust-lang/rust/issues/99909
Fixes #59998

cc `@eddyb`

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -656,9 +656,7 @@ impl<'a> Linker for GccLinker<'a> {
             return;
         }
 
-        if crate_type == CrateType::ProcMacro {
-            return;
-        }
+        // FIXME(#99978) hide #[no_mangle] symbols for proc-macros
 
         let is_windows = self.sess.target.is_like_windows;
         let path = tmpdir.join(if is_windows { "list.def" } else { "list" });

compiler/rustc_codegen_ssa/src/back/symbol_export.rs

@@ -257,16 +257,18 @@ fn exported_symbols_provider_local<'tcx>(
         }));
     }
 
-    if tcx.sess.crate_types().contains(&CrateType::Dylib) {
+    if tcx.sess.crate_types().contains(&CrateType::Dylib)
+        || tcx.sess.crate_types().contains(&CrateType::ProcMacro)
+    {
         let symbol_name = metadata_symbol_name(tcx);
         let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, &symbol_name));
 
         symbols.push((
             exported_symbol,
             SymbolExportInfo {
-                level: SymbolExportLevel::Rust,
+                level: SymbolExportLevel::C,
                 kind: SymbolExportKind::Data,
-                used: false,
+                used: true,
             },
         ));
     }

src/test/run-make-fulldeps/symbol-visibility/Makefile

@@ -5,6 +5,7 @@ include ../tools.mk
 NM=nm -D
 CDYLIB_NAME=liba_cdylib.so
 RDYLIB_NAME=liba_rust_dylib.so
+PROC_MACRO_NAME=liba_proc_macro.so
 EXE_NAME=an_executable
 COMBINED_CDYLIB_NAME=libcombined_rlib_dylib.so
 
@@ -12,6 +13,7 @@ ifeq ($(UNAME),Darwin)
 NM=nm -gU
 CDYLIB_NAME=liba_cdylib.dylib
 RDYLIB_NAME=liba_rust_dylib.dylib
+PROC_MACRO_NAME=liba_proc_macro.dylib
 EXE_NAME=an_executable
 COMBINED_CDYLIB_NAME=libcombined_rlib_dylib.dylib
 endif
@@ -20,6 +22,7 @@ ifdef IS_WINDOWS
 NM=nm -g
 CDYLIB_NAME=liba_cdylib.dll.a
 RDYLIB_NAME=liba_rust_dylib.dll.a
+PROC_MACRO_NAME=liba_proc_macro.dll
 EXE_NAME=an_executable.exe
 COMBINED_CDYLIB_NAME=libcombined_rlib_dylib.dll.a
 endif
@@ -31,6 +34,7 @@ all:
 	$(RUSTC) -Zshare-generics=no an_rlib.rs
 	$(RUSTC) -Zshare-generics=no a_cdylib.rs
 	$(RUSTC) -Zshare-generics=no a_rust_dylib.rs
+	$(RUSTC) -Zshare-generics=no a_proc_macro.rs
 	$(RUSTC) -Zshare-generics=no an_executable.rs
 	$(RUSTC) -Zshare-generics=no a_cdylib.rs --crate-name combined_rlib_dylib --crate-type=rlib,cdylib
 
@@ -54,6 +58,14 @@ all:
 	# Check that a Rust dylib does not export generics if -Zshare-generics=no
 	[ "$$($(NM) $(TMPDIR)/$(RDYLIB_NAME) | grep -v __imp_ | grep -c public_generic_function_from_rlib)" -eq "0" ]
 
+	# Check that a proc macro exports its public #[no_mangle] functions
+	# FIXME(#99978) avoid exporting #[no_mangle] symbols for proc macros
+	[ "$$($(NM) $(TMPDIR)/$(CDYLIB_NAME) | grep -v __imp_ | grep -c public_c_function_from_cdylib)" -eq "1" ]
+	# Check that a proc macro exports the public #[no_mangle] functions of dependencies
+	[ "$$($(NM) $(TMPDIR)/$(CDYLIB_NAME) | grep -v __imp_ | grep -c public_c_function_from_rlib)" -eq "1" ]
+	# Check that a proc macro DOES NOT export any public Rust functions
+	[ "$$($(NM) $(TMPDIR)/$(CDYLIB_NAME) | grep -v __imp_ | grep -c $(RE_ANY_RUST_SYMBOL))" -eq "0" ]
+
 # FIXME(nbdd0121): This is broken in MinGW, see https://github.com/rust-lang/rust/pull/95604#issuecomment-1101564032
 ifndef IS_WINDOWS
 	# Check that an executable does not export any dynamic symbols
@@ -75,6 +87,7 @@ endif
 	$(RUSTC) -Zshare-generics=yes an_rlib.rs
 	$(RUSTC) -Zshare-generics=yes a_cdylib.rs
 	$(RUSTC) -Zshare-generics=yes a_rust_dylib.rs
+	$(RUSTC) -Zshare-generics=yes a_proc_macro.rs
 	$(RUSTC) -Zshare-generics=yes an_executable.rs
 
 	# Check that a cdylib exports its public #[no_mangle] functions
@@ -94,6 +107,14 @@ endif
 	[ "$$($(NM) $(TMPDIR)/$(RDYLIB_NAME) | grep -v __imp_ | grep -c public_rust_function_from_rlib)" -eq "1" ]
 	[ "$$($(NM) $(TMPDIR)/$(RDYLIB_NAME) | grep -v __imp_ | grep -c public_generic_function_from_rlib)" -eq "1" ]
 
+	# Check that a proc macro exports its public #[no_mangle] functions
+	# FIXME(#99978) avoid exporting #[no_mangle] symbols for proc macros
+	[ "$$($(NM) $(TMPDIR)/$(CDYLIB_NAME) | grep -v __imp_ | grep -c public_c_function_from_cdylib)" -eq "1" ]
+	# Check that a proc macro exports the public #[no_mangle] functions of dependencies
+	[ "$$($(NM) $(TMPDIR)/$(CDYLIB_NAME) | grep -v __imp_ | grep -c public_c_function_from_rlib)" -eq "1" ]
+	# Check that a proc macro DOES NOT export any public Rust functions
+	[ "$$($(NM) $(TMPDIR)/$(CDYLIB_NAME) | grep -v __imp_ | grep -c $(RE_ANY_RUST_SYMBOL))" -eq "0" ]
+
 ifndef IS_WINDOWS
 	# Check that an executable does not export any dynamic symbols
 	[ "$$($(NM) $(TMPDIR)/$(EXE_NAME) | grep -v __imp_ | grep -c public_c_function_from_rlib)" -eq "0" ]

src/test/run-make-fulldeps/symbol-visibility/a_proc_macro.rs

@@ -0,0 +1,9 @@
+#![crate_type = "proc-macro"]
+
+extern crate an_rlib;
+
+// This should not be exported
+#[no_mangle]
+extern "C" fn public_c_function_from_cdylib() {
+    an_rlib::public_c_function_from_rlib();
+}

src/test/ui/proc-macro/invalid-punct-ident-1.rs

@@ -1,9 +1,4 @@
 // aux-build:invalid-punct-ident.rs
-// ignore-stage1
-// only-linux
-//
-// FIXME: This should be a normal (stage1, all platforms) test in
-// src/test/ui/proc-macro once issue #59998 is fixed.
 
 #[macro_use]
 extern crate invalid_punct_ident;

src/test/ui/proc-macro/invalid-punct-ident-1.stderr

@@ -1,5 +1,5 @@
 error: proc macro panicked
-  --> $DIR/invalid-punct-ident-1.rs:11:1
+  --> $DIR/invalid-punct-ident-1.rs:6:1
    |
 LL | invalid_punct!();
    | ^^^^^^^^^^^^^^^^

src/test/ui/proc-macro/invalid-punct-ident-2.rs

@@ -1,9 +1,4 @@
 // aux-build:invalid-punct-ident.rs
-// ignore-stage1
-// only-linux
-//
-// FIXME: This should be a normal (stage1, all platforms) test in
-// src/test/ui/proc-macro once issue #59998 is fixed.
 
 #[macro_use]
 extern crate invalid_punct_ident;

src/test/ui/proc-macro/invalid-punct-ident-2.stderr

@@ -1,5 +1,5 @@
 error: proc macro panicked
-  --> $DIR/invalid-punct-ident-2.rs:11:1
+  --> $DIR/invalid-punct-ident-2.rs:6:1
    |
 LL | invalid_ident!();
    | ^^^^^^^^^^^^^^^^

src/test/ui/proc-macro/invalid-punct-ident-3.rs

@@ -1,9 +1,4 @@
 // aux-build:invalid-punct-ident.rs
-// ignore-stage1
-// only-linux
-//
-// FIXME: This should be a normal (stage1, all platforms) test in
-// src/test/ui/proc-macro once issue #59998 is fixed.
 
 #[macro_use]
 extern crate invalid_punct_ident;

src/test/ui/proc-macro/invalid-punct-ident-3.stderr

@@ -1,5 +1,5 @@
 error: proc macro panicked
-  --> $DIR/invalid-punct-ident-3.rs:11:1
+  --> $DIR/invalid-punct-ident-3.rs:6:1
    |
 LL | invalid_raw_ident!();
    | ^^^^^^^^^^^^^^^^^^^^

src/test/ui/proc-macro/issue-76270-panic-in-libproc-macro.rs

@@ -1,10 +1,5 @@
 // aux-build:proc-macro-panic.rs
 // edition:2018
-// ignore-stage1
-// only-linux
-//
-// FIXME: This should be a normal (stage1, all platforms) test in
-// src/test/ui/proc-macro once issue #59998 is fixed.
 
 // Regression test for issue #76270
 // Tests that we don't print an ICE message when a panic

src/test/ui/proc-macro/issue-76270-panic-in-libproc-macro.stderr

@@ -1,5 +1,5 @@
 error: proc macro panicked
-  --> $DIR/issue-76270-panic-in-libproc-macro.rs:15:1
+  --> $DIR/issue-76270-panic-in-libproc-macro.rs:10:1
    |
 LL | proc_macro_panic::panic_in_libproc_macro!();
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

src/test/ui/proc-macro/load-panic-backtrace.rs

@@ -1,18 +1,8 @@
 // aux-build:test-macros.rs
 // compile-flags: -Z proc-macro-backtrace
 // rustc-env:RUST_BACKTRACE=0
-
-// FIXME https://github.com/rust-lang/rust/issues/59998
 // normalize-stderr-test "thread '.*' panicked " -> ""
 // normalize-stderr-test "note:.*RUST_BACKTRACE=1.*\n" -> ""
-// normalize-stderr-test "\nerror: internal compiler error.*\n\n" -> ""
-// normalize-stderr-test "note:.*unexpectedly panicked.*\n\n" -> ""
-// normalize-stderr-test "note: we would appreciate a bug report.*\n\n" -> ""
-// normalize-stderr-test "note: compiler flags.*\n\n" -> ""
-// normalize-stderr-test "note: rustc.*running on.*\n\n" -> ""
-// normalize-stderr-test "query stack during panic:\n" -> ""
-// normalize-stderr-test "we're just showing a limited slice of the query stack\n" -> ""
-// normalize-stderr-test "end of query stack\n" -> ""
 
 #[macro_use]
 extern crate test_macros;

src/test/ui/proc-macro/load-panic-backtrace.stderr

@@ -1,6 +1,6 @@
 at 'panic-derive', $DIR/auxiliary/test-macros.rs:43:5
 error: proc-macro derive panicked
-  --> $DIR/load-panic-backtrace.rs:20:10
+  --> $DIR/load-panic-backtrace.rs:10:10
    |
 LL | #[derive(Panic)]
    |          ^^^^^