[LLD][COFF] Demangle ARM64EC export names.

lld/COFF/DriverUtils.cpp

@@ -21,6 +21,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/BinaryFormat/COFF.h"
+#include "llvm/IR/Mangler.h"
 #include "llvm/Object/COFF.h"
 #include "llvm/Object/WindowsResource.h"
 #include "llvm/Option/Arg.h"
@@ -39,6 +40,7 @@
 #include <optional>
 
 using namespace llvm::COFF;
+using namespace llvm::object;
 using namespace llvm::opt;
 using namespace llvm;
 using llvm::sys::Process;
@@ -632,18 +634,6 @@ Export LinkerDriver::parseExport(StringRef arg) {
   fatal("invalid /export: " + arg);
 }
 
-static StringRef undecorate(COFFLinkerContext &ctx, StringRef sym) {
-  if (ctx.config.machine != I386)
-    return sym;
-  // In MSVC mode, a fully decorated stdcall function is exported
-  // as-is with the leading underscore (with type IMPORT_NAME).
-  // In MinGW mode, a decorated stdcall function gets the underscore
-  // removed, just like normal cdecl functions.
-  if (sym.starts_with("_") && sym.contains('@') && !ctx.config.mingw)
-    return sym;
-  return sym.starts_with("_") ? sym.substr(1) : sym;
-}
-
 // Convert stdcall/fastcall style symbols into unsuffixed symbols,
 // with or without a leading underscore. (MinGW specific.)
 static StringRef killAt(StringRef sym, bool prefix) {
@@ -693,11 +683,29 @@ void LinkerDriver::fixupExports() {
   for (Export &e : ctx.config.exports) {
     if (!e.exportAs.empty()) {
       e.exportName = e.exportAs;
-    } else if (!e.forwardTo.empty()) {
-      e.exportName = undecorate(ctx, e.name);
-    } else {
-      e.exportName = undecorate(ctx, e.extName.empty() ? e.name : e.extName);
+      continue;
+    }
+
+    StringRef sym =
+        !e.forwardTo.empty() || e.extName.empty() ? e.name : e.extName;
+    if (ctx.config.machine == I386 && sym.starts_with("_")) {
+      // In MSVC mode, a fully decorated stdcall function is exported
+      // as-is with the leading underscore (with type IMPORT_NAME).
+      // In MinGW mode, a decorated stdcall function gets the underscore
+      // removed, just like normal cdecl functions.
+      if (ctx.config.mingw || !sym.contains('@')) {
+        e.exportName = sym.substr(1);
+        continue;
+      }
+    }
+    if (isArm64EC(ctx.config.machine) && !e.data && !e.constant) {
+      if (std::optional<std::string> demangledName =
+              getArm64ECDemangledFunctionName(sym)) {
+        e.exportName = saver().save(*demangledName);
+        continue;
+      }
     }
+    e.exportName = sym;
   }
 
   if (ctx.config.killAt && ctx.config.machine == I386) {

lld/test/COFF/arm64ec-exports.s

@@ -0,0 +1,121 @@
+; REQUIRES: aarch64
+; RUN: split-file %s %t.dir && cd %t.dir
+
+; RUN: llvm-mc -filetype=obj -triple=arm64ec-windows test.s -o test.obj
+; RUN: llvm-mc -filetype=obj -triple=arm64ec-windows drectve.s -o drectve.obj
+; RUN: llvm-mc -filetype=obj -triple=arm64ec-windows %S/Inputs/loadconfig-arm64ec.s -o loadconfig-arm64ec.obj
+
+; Check various forms of export directive and make sure that function export name is demangled.
+
+; RUN: lld-link -out:out.dll test.obj loadconfig-arm64ec.obj -dll -noentry -machine:arm64ec \
+; RUN:          -export:unmangled_func '-export:#mangled_func' '-export:#exportas_func,EXPORTAS,exportas_func' \
+; RUN:          '-export:?cxx_func@@$$hYAHXZ' -export:data_sym,DATA '-export:#mangled_data_sym,DATA'
+
+
+; RUN: llvm-readobj --coff-exports out.dll | FileCheck --check-prefix=EXP %s
+; EXP:      Export {
+; EXP-NEXT:   Ordinal: 1
+; EXP-NEXT:   Name: #mangled_data_sym
+; EXP-NEXT:   RVA: 0x3000
+; EXP-NEXT: }
+; EXP-NEXT: Export {
+; EXP-NEXT:   Ordinal: 2
+; EXP-NEXT:   Name: ?cxx_func@@YAHXZ
+; EXP-NEXT:   RVA: 0x1018
+; EXP-NEXT: }
+; EXP-NEXT: Export {
+; EXP-NEXT:   Ordinal: 3
+; EXP-NEXT:   Name: data_sym
+; EXP-NEXT:   RVA: 0x3004
+; EXP-NEXT: }
+; EXP-NEXT: Export {
+; EXP-NEXT:   Ordinal: 4
+; EXP-NEXT:   Name: exportas_func
+; EXP-NEXT:   RVA: 0x1010
+; EXP-NEXT: }
+; EXP-NEXT: Export {
+; EXP-NEXT:   Ordinal: 5
+; EXP-NEXT:   Name: mangled_func
+; EXP-NEXT:   RVA: 0x1008
+; EXP-NEXT: }
+; EXP-NEXT: Export {
+; EXP-NEXT:   Ordinal: 6
+; EXP-NEXT:   Name: unmangled_func
+; EXP-NEXT:   RVA: 0x1000
+; EXP-NEXT: }
+
+; RUN: llvm-nm --print-armap out.lib | FileCheck --check-prefix=IMPLIB %s
+; IMPLIB:      Archive EC map
+; IMPLIB-NEXT: #exportas_func in out
+; IMPLIB-NEXT: #mangled_func in out
+; IMPLIB-NEXT: #unmangled_func in out
+; IMPLIB-NEXT: ?cxx_func@@$$hYAHXZ in out
+; IMPLIB-NEXT: ?cxx_func@@YAHXZ in out
+; IMPLIB-NEXT: __IMPORT_DESCRIPTOR_out{{.*}} in out
+; IMPLIB-NEXT: __NULL_IMPORT_DESCRIPTOR in out
+; IMPLIB-NEXT: __imp_?cxx_func@@YAHXZ in out
+; IMPLIB-NEXT: __imp_aux_?cxx_func@@YAHXZ in out
+; IMPLIB-NEXT: __imp_aux_exportas_func in out
+; IMPLIB-NEXT: __imp_aux_mangled_func in out
+; IMPLIB-NEXT: __imp_aux_unmangled_func in out
+; IMPLIB-NEXT: __imp_data_sym in out
+; IMPLIB-NEXT: __imp_exportas_func in out
+; IMPLIB-NEXT: __imp_mangled_data_sym in out
+; IMPLIB-NEXT: __imp_mangled_func in out
+; IMPLIB-NEXT: __imp_unmangled_func in out
+; IMPLIB-NEXT: exportas_func in out
+; IMPLIB-NEXT: mangled_func in out
+; IMPLIB-NEXT: unmangled_func in out
+; IMPLIB-NEXT: out{{.*}}_NULL_THUNK_DATA in out
+
+
+; Check that using .drectve section has the same effect.
+
+; RUN: lld-link -out:out2.dll test.obj loadconfig-arm64ec.obj -dll -noentry -machine:arm64ec drectve.obj
+; RUN: llvm-readobj --coff-exports out2.dll | FileCheck --check-prefix=EXP %s
+; RUN: llvm-nm --print-armap out2.lib | FileCheck --check-prefix=IMPLIB %s
+
+#--- test.s
+        .text
+        .globl unmangled_func
+        .p2align 2, 0x0
+unmangled_func:
+        mov w0, #1
+        ret
+
+        .globl "#mangled_func"
+        .p2align 2, 0x0
+"#mangled_func":
+        mov w0, #2
+        ret
+
+        .globl "#exportas_func"
+        .p2align 2, 0x0
+"#exportas_func":
+        mov w0, #3
+        ret
+
+        .globl "?cxx_func@@$$hYAHXZ"
+        .p2align 2, 0x0
+"?cxx_func@@$$hYAHXZ":
+        mov w0, #4
+        ret
+
+        .data
+        .globl "#mangled_data_sym"
+        .p2align 2, 0x0
+"#mangled_data_sym":
+        .word 0x01010101
+        .globl data_sym
+        .p2align 2, 0x0
+data_sym:
+        .word 0x01010101
+
+#--- drectve.s
+        .section .drectve, "yn"
+        .ascii " -export:unmangled_func"
+        .ascii " -export:#mangled_func"
+        .ascii " -export:#exportas_func,EXPORTAS,exportas_func"
+        .ascii " -export:?cxx_func@@$$hYAHXZ"
+        .ascii " -export:data_sym,DATA"
+        .ascii " -export:#mangled_data_sym,DATA"