[Arm64EC] Only decorate functions with `#`

4 files changed, 141 insertions, 49 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs
index 8fc83908efb..b6892bb63e8 100644
--- a/compiler/rustc_codegen_ssa/src/back/linker.rs
+++ b/compiler/rustc_codegen_ssa/src/back/linker.rs
@@ -337,7 +337,12 @@ pub(crate) trait Linker {
     fn debuginfo(&mut self, strip: Strip, natvis_debugger_visualizers: &[PathBuf]);
     fn no_crt_objects(&mut self);
     fn no_default_libraries(&mut self);
-    fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType, symbols: &[String]);
+    fn export_symbols(
+        &mut self,
+        tmpdir: &Path,
+        crate_type: CrateType,
+        symbols: &[(String, SymbolExportKind)],
+    );
     fn subsystem(&mut self, subsystem: &str);
     fn linker_plugin_lto(&mut self);
     fn add_eh_frame_header(&mut self) {}
@@ -770,7 +775,12 @@ impl<'a> Linker for GccLinker<'a> {
         }
     }
 
-    fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType, symbols: &[String]) {
+    fn export_symbols(
+        &mut self,
+        tmpdir: &Path,
+        crate_type: CrateType,
+        symbols: &[(String, SymbolExportKind)],
+    ) {
         // Symbol visibility in object files typically takes care of this.
         if crate_type == CrateType::Executable {
             let should_export_executable_symbols =
@@ -799,7 +809,7 @@ impl<'a> Linker for GccLinker<'a> {
             // Write a plain, newline-separated list of symbols
             let res: io::Result<()> = try {
                 let mut f = File::create_buffered(&path)?;
-                for sym in symbols {
+                for (sym, _) in symbols {
                     debug!("  _{sym}");
                     writeln!(f, "_{sym}")?;
                 }
@@ -814,11 +824,12 @@ impl<'a> Linker for GccLinker<'a> {
                 // .def file similar to MSVC one but without LIBRARY section
                 // because LD doesn't like when it's empty
                 writeln!(f, "EXPORTS")?;
-                for symbol in symbols {
+                for (symbol, kind) in symbols {
+                    let kind_marker = if *kind == SymbolExportKind::Data { " DATA" } else { "" };
                     debug!("  _{symbol}");
                     // Quote the name in case it's reserved by linker in some way
                     // (this accounts for names with dots in particular).
-                    writeln!(f, "  \"{symbol}\"")?;
+                    writeln!(f, "  \"{symbol}\"{kind_marker}")?;
                 }
             };
             if let Err(error) = res {
@@ -831,7 +842,7 @@ impl<'a> Linker for GccLinker<'a> {
                 writeln!(f, "{{")?;
                 if !symbols.is_empty() {
                     writeln!(f, "  global:")?;
-                    for sym in symbols {
+                    for (sym, _) in symbols {
                         debug!("    {sym};");
                         writeln!(f, "    {sym};")?;
                     }
@@ -1098,7 +1109,12 @@ impl<'a> Linker for MsvcLinker<'a> {
     // crates. Upstream rlibs may be linked statically to this dynamic library,
     // in which case they may continue to transitively be used and hence need
     // their symbols exported.
-    fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType, symbols: &[String]) {
+    fn export_symbols(
+        &mut self,
+        tmpdir: &Path,
+        crate_type: CrateType,
+        symbols: &[(String, SymbolExportKind)],
+    ) {
         // Symbol visibility takes care of this typically
         if crate_type == CrateType::Executable {
             let should_export_executable_symbols =
@@ -1116,9 +1132,10 @@ impl<'a> Linker for MsvcLinker<'a> {
             // straight to exports.
             writeln!(f, "LIBRARY")?;
             writeln!(f, "EXPORTS")?;
-            for symbol in symbols {
+            for (symbol, kind) in symbols {
+                let kind_marker = if *kind == SymbolExportKind::Data { " DATA" } else { "" };
                 debug!("  _{symbol}");
-                writeln!(f, "  {symbol}")?;
+                writeln!(f, "  {symbol}{kind_marker}")?;
             }
         };
         if let Err(error) = res {
@@ -1259,14 +1276,19 @@ impl<'a> Linker for EmLinker<'a> {
         self.cc_arg("-nodefaultlibs");
     }
 
-    fn export_symbols(&mut self, _tmpdir: &Path, _crate_type: CrateType, symbols: &[String]) {
+    fn export_symbols(
+        &mut self,
+        _tmpdir: &Path,
+        _crate_type: CrateType,
+        symbols: &[(String, SymbolExportKind)],
+    ) {
         debug!("EXPORTED SYMBOLS:");
 
         self.cc_arg("-s");
 
         let mut arg = OsString::from("EXPORTED_FUNCTIONS=");
         let encoded = serde_json::to_string(
-            &symbols.iter().map(|sym| "_".to_owned() + sym).collect::<Vec<_>>(),
+            &symbols.iter().map(|(sym, _)| "_".to_owned() + sym).collect::<Vec<_>>(),
         )
         .unwrap();
         debug!("{encoded}");
@@ -1428,8 +1450,13 @@ impl<'a> Linker for WasmLd<'a> {
 
     fn no_default_libraries(&mut self) {}
 
-    fn export_symbols(&mut self, _tmpdir: &Path, _crate_type: CrateType, symbols: &[String]) {
-        for sym in symbols {
+    fn export_symbols(
+        &mut self,
+        _tmpdir: &Path,
+        _crate_type: CrateType,
+        symbols: &[(String, SymbolExportKind)],
+    ) {
+        for (sym, _) in symbols {
             self.link_args(&["--export", sym]);
         }
 
@@ -1563,7 +1590,7 @@ impl<'a> Linker for L4Bender<'a> {
         self.cc_arg("-nostdlib");
     }
 
-    fn export_symbols(&mut self, _: &Path, _: CrateType, _: &[String]) {
+    fn export_symbols(&mut self, _: &Path, _: CrateType, _: &[(String, SymbolExportKind)]) {
         // ToDo, not implemented, copy from GCC
         self.sess.dcx().emit_warn(errors::L4BenderExportingSymbolsUnimplemented);
     }
@@ -1720,12 +1747,17 @@ impl<'a> Linker for AixLinker<'a> {
 
     fn no_default_libraries(&mut self) {}
 
-    fn export_symbols(&mut self, tmpdir: &Path, _crate_type: CrateType, symbols: &[String]) {
+    fn export_symbols(
+        &mut self,
+        tmpdir: &Path,
+        _crate_type: CrateType,
+        symbols: &[(String, SymbolExportKind)],
+    ) {
         let path = tmpdir.join("list.exp");
         let res: io::Result<()> = try {
             let mut f = File::create_buffered(&path)?;
             // FIXME: use llvm-nm to generate export list.
-            for symbol in symbols {
+            for (symbol, _) in symbols {
                 debug!("  _{symbol}");
                 writeln!(f, "  {symbol}")?;
             }
@@ -1769,9 +1801,23 @@ fn for_each_exported_symbols_include_dep<'tcx>(
     }
 }
 
-pub(crate) fn exported_symbols(tcx: TyCtxt<'_>, crate_type: CrateType) -> Vec<String> {
+pub(crate) fn exported_symbols(
+    tcx: TyCtxt<'_>,
+    crate_type: CrateType,
+) -> Vec<(String, SymbolExportKind)> {
     if let Some(ref exports) = tcx.sess.target.override_export_symbols {
-        return exports.iter().map(ToString::to_string).collect();
+        return exports
+            .iter()
+            .map(|name| {
+                (
+                    name.to_string(),
+                    // FIXME use the correct export kind for this symbol. override_export_symbols
+                    // can't directly specify the SymbolExportKind as it is defined in rustc_middle
+                    // which rustc_target can't depend on.
+                    SymbolExportKind::Text,
+                )
+            })
+            .collect();
     }
 
     if let CrateType::ProcMacro = crate_type {
@@ -1781,7 +1827,10 @@ pub(crate) fn exported_symbols(tcx: TyCtxt<'_>, crate_type: CrateType) -> Vec<St
     }
 }
 
-fn exported_symbols_for_non_proc_macro(tcx: TyCtxt<'_>, crate_type: CrateType) -> Vec<String> {
+fn exported_symbols_for_non_proc_macro(
+    tcx: TyCtxt<'_>,
+    crate_type: CrateType,
+) -> Vec<(String, SymbolExportKind)> {
     let mut symbols = Vec::new();
     let export_threshold = symbol_export::crates_export_threshold(&[crate_type]);
     for_each_exported_symbols_include_dep(tcx, crate_type, |symbol, info, cnum| {
@@ -1789,8 +1838,9 @@ fn exported_symbols_for_non_proc_macro(tcx: TyCtxt<'_>, crate_type: CrateType) -
         // from any cdylib. The latter doesn't work anyway as we use hidden visibility for
         // compiler-builtins. Most linkers silently ignore it, but ld64 gives a warning.
         if info.level.is_below_threshold(export_threshold) && !tcx.is_compiler_builtins(cnum) {
-            symbols.push(symbol_export::exporting_symbol_name_for_instance_in_crate(
-                tcx, symbol, cnum,
+            symbols.push((
+                symbol_export::exporting_symbol_name_for_instance_in_crate(tcx, symbol, cnum),
+                info.kind,
             ));
             symbol_export::extend_exported_symbols(&mut symbols, tcx, symbol, cnum);
         }
@@ -1799,7 +1849,7 @@ fn exported_symbols_for_non_proc_macro(tcx: TyCtxt<'_>, crate_type: CrateType) -
     symbols
 }
 
-fn exported_symbols_for_proc_macro_crate(tcx: TyCtxt<'_>) -> Vec<String> {
+fn exported_symbols_for_proc_macro_crate(tcx: TyCtxt<'_>) -> Vec<(String, SymbolExportKind)> {
     // `exported_symbols` will be empty when !should_codegen.
     if !tcx.sess.opts.output_types.should_codegen() {
         return Vec::new();
@@ -1809,7 +1859,10 @@ fn exported_symbols_for_proc_macro_crate(tcx: TyCtxt<'_>) -> Vec<String> {
     let proc_macro_decls_name = tcx.sess.generate_proc_macro_decls_symbol(stable_crate_id);
     let metadata_symbol_name = exported_symbols::metadata_symbol_name(tcx);
 
-    vec![proc_macro_decls_name, metadata_symbol_name]
+    vec![
+        (proc_macro_decls_name, SymbolExportKind::Data),
+        (metadata_symbol_name, SymbolExportKind::Data),
+    ]
 }
 
 pub(crate) fn linked_symbols(
@@ -1831,7 +1884,9 @@ pub(crate) fn linked_symbols(
             || info.used
         {
             symbols.push((
-                symbol_export::linking_symbol_name_for_instance_in_crate(tcx, symbol, cnum),
+                symbol_export::linking_symbol_name_for_instance_in_crate(
+                    tcx, symbol, info.kind, cnum,
+                ),
                 info.kind,
             ));
         }
@@ -1906,7 +1961,13 @@ impl<'a> Linker for PtxLinker<'a> {
 
     fn ehcont_guard(&mut self) {}
 
-    fn export_symbols(&mut self, _tmpdir: &Path, _crate_type: CrateType, _symbols: &[String]) {}
+    fn export_symbols(
+        &mut self,
+        _tmpdir: &Path,
+        _crate_type: CrateType,
+        _symbols: &[(String, SymbolExportKind)],
+    ) {
+    }
 
     fn subsystem(&mut self, _subsystem: &str) {}
 
@@ -1975,10 +2036,15 @@ impl<'a> Linker for LlbcLinker<'a> {
 
     fn ehcont_guard(&mut self) {}
 
-    fn export_symbols(&mut self, _tmpdir: &Path, _crate_type: CrateType, symbols: &[String]) {
+    fn export_symbols(
+        &mut self,
+        _tmpdir: &Path,
+        _crate_type: CrateType,
+        symbols: &[(String, SymbolExportKind)],
+    ) {
         match _crate_type {
             CrateType::Cdylib => {
-                for sym in symbols {
+                for (sym, _) in symbols {
                     self.link_args(&["--export-symbol", sym]);
                 }
             }
@@ -2052,11 +2118,16 @@ impl<'a> Linker for BpfLinker<'a> {
 
     fn ehcont_guard(&mut self) {}
 
-    fn export_symbols(&mut self, tmpdir: &Path, _crate_type: CrateType, symbols: &[String]) {
+    fn export_symbols(
+        &mut self,
+        tmpdir: &Path,
+        _crate_type: CrateType,
+        symbols: &[(String, SymbolExportKind)],
+    ) {
         let path = tmpdir.join("symbols");
         let res: io::Result<()> = try {
             let mut f = File::create_buffered(&path)?;
-            for sym in symbols {
+            for (sym, _) in symbols {
                 writeln!(f, "{sym}")?;
             }
         };
diff --git a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
index d0b6c7470fb..19c005d418e 100644
--- a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
+++ b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
@@ -680,6 +680,7 @@ fn calling_convention_for_symbol<'tcx>(
 pub(crate) fn linking_symbol_name_for_instance_in_crate<'tcx>(
     tcx: TyCtxt<'tcx>,
     symbol: ExportedSymbol<'tcx>,
+    export_kind: SymbolExportKind,
     instantiating_crate: CrateNum,
 ) -> String {
     let mut undecorated = symbol_name_for_instance_in_crate(tcx, symbol, instantiating_crate);
@@ -700,8 +701,9 @@ pub(crate) fn linking_symbol_name_for_instance_in_crate<'tcx>(
     let prefix = match &target.arch[..] {
         "x86" => Some('_'),
         "x86_64" => None,
-        "arm64ec" => Some('#'),
-        // Only x86/64 use symbol decorations.
+        // Only functions are decorated for arm64ec.
+        "arm64ec" if export_kind == SymbolExportKind::Text => Some('#'),
+        // Only x86/64 and arm64ec use symbol decorations.
         _ => return undecorated,
     };
 
@@ -741,7 +743,7 @@ pub(crate) fn exporting_symbol_name_for_instance_in_crate<'tcx>(
 /// Add it to the symbols list for all kernel functions, so that it is exported in the linked
 /// object.
 pub(crate) fn extend_exported_symbols<'tcx>(
-    symbols: &mut Vec<String>,
+    symbols: &mut Vec<(String, SymbolExportKind)>,
     tcx: TyCtxt<'tcx>,
     symbol: ExportedSymbol<'tcx>,
     instantiating_crate: CrateNum,
@@ -755,7 +757,9 @@ pub(crate) fn extend_exported_symbols<'tcx>(
     let undecorated = symbol_name_for_instance_in_crate(tcx, symbol, instantiating_crate);
 
     // Add the symbol for the kernel descriptor (with .kd suffix)
-    symbols.push(format!("{undecorated}.kd"));
+    // Per https://llvm.org/docs/AMDGPUUsage.html#symbols these will always be `STT_OBJECT` so
+    // export as data.
+    symbols.push((format!("{undecorated}.kd"), SymbolExportKind::Data));
 }
 
 fn maybe_emutls_symbol_name<'tcx>(
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index a3d6c73ba85..cc90271cd0c 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -12,9 +12,9 @@ use rustc_data_structures::fx::{FxHashMap, FxIndexSet};
 use rustc_data_structures::profiling::{get_resident_set_size, print_time_passes_entry};
 use rustc_data_structures::sync::{IntoDynSyncSend, par_map};
 use rustc_data_structures::unord::UnordMap;
-use rustc_hir::ItemId;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_hir::lang_items::LangItem;
+use rustc_hir::{ItemId, Target};
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
 use rustc_middle::middle::debugger_visualizer::{DebuggerVisualizerFile, DebuggerVisualizerType};
 use rustc_middle::middle::exported_symbols::{self, SymbolExportKind};
@@ -1003,21 +1003,35 @@ impl CrateInfo {
         // by the compiler, but that's ok because all this stuff is unstable anyway.
         let target = &tcx.sess.target;
         if !are_upstream_rust_objects_already_included(tcx.sess) {
-            let missing_weak_lang_items: FxIndexSet<Symbol> = info
+            let add_prefix = match (target.is_like_windows, target.arch.as_ref()) {
+                (true, "x86") => |name: String, _: SymbolExportKind| format!("_{name}"),
+                (true, "arm64ec") => {
+                    // Only functions are decorated for arm64ec.
+                    |name: String, export_kind: SymbolExportKind| match export_kind {
+                        SymbolExportKind::Text => format!("#{name}"),
+                        _ => name,
+                    }
+                }
+                _ => |name: String, _: SymbolExportKind| name,
+            };
+            let missing_weak_lang_items: FxIndexSet<(Symbol, SymbolExportKind)> = info
                 .used_crates
                 .iter()
                 .flat_map(|&cnum| tcx.missing_lang_items(cnum))
                 .filter(|l| l.is_weak())
                 .filter_map(|&l| {
                     let name = l.link_name()?;
-                    lang_items::required(tcx, l).then_some(name)
+                    let export_kind = match l.target() {
+                        Target::Fn => SymbolExportKind::Text,
+                        Target::Static => SymbolExportKind::Data,
+                        _ => bug!(
+                            "Don't know what the export kind is for lang item of kind {:?}",
+                            l.target()
+                        ),
+                    };
+                    lang_items::required(tcx, l).then_some((name, export_kind))
                 })
                 .collect();
-            let prefix = match (target.is_like_windows, target.arch.as_ref()) {
-                (true, "x86") => "_",
-                (true, "arm64ec") => "#",
-                _ => "",
-            };
 
             // This loop only adds new items to values of the hash map, so the order in which we
             // iterate over the values is not important.
@@ -1030,10 +1044,13 @@ impl CrateInfo {
                 .for_each(|(_, linked_symbols)| {
                     let mut symbols = missing_weak_lang_items
                         .iter()
-                        .map(|item| {
+                        .map(|(item, export_kind)| {
                             (
-                                format!("{prefix}{}", mangle_internal_symbol(tcx, item.as_str())),
-                                SymbolExportKind::Text,
+                                add_prefix(
+                                    mangle_internal_symbol(tcx, item.as_str()),
+                                    *export_kind,
+                                ),
+                                *export_kind,
                             )
                         })
                         .collect::<Vec<_>>();
@@ -1048,12 +1065,12 @@ impl CrateInfo {
                         // errors.
                         linked_symbols.extend(ALLOCATOR_METHODS.iter().map(|method| {
                             (
-                                format!(
-                                    "{prefix}{}",
+                                add_prefix(
                                     mangle_internal_symbol(
                                         tcx,
-                                        global_fn_name(method.name).as_str()
-                                    )
+                                        global_fn_name(method.name).as_str(),
+                                    ),
+                                    SymbolExportKind::Text,
                                 ),
                                 SymbolExportKind::Text,
                             )
diff --git a/compiler/rustc_codegen_ssa/src/lib.rs b/compiler/rustc_codegen_ssa/src/lib.rs
index 523c9f2ad1c..23ed387a3ff 100644
--- a/compiler/rustc_codegen_ssa/src/lib.rs
+++ b/compiler/rustc_codegen_ssa/src/lib.rs
@@ -218,7 +218,7 @@ pub struct CrateInfo {
     pub target_cpu: String,
     pub target_features: Vec<String>,
     pub crate_types: Vec<CrateType>,
-    pub exported_symbols: UnordMap<CrateType, Vec<String>>,
+    pub exported_symbols: UnordMap<CrateType, Vec<(String, SymbolExportKind)>>,
     pub linked_symbols: FxIndexMap<CrateType, Vec<(String, SymbolExportKind)>>,
     pub local_crate_name: Symbol,
     pub compiler_builtins: Option<CrateNum>,