[LLD][COFF] Add support for -includeoptional on ARM64X (#126300)

Include symbols from both symbol tables.

Author: cjacek

lld/COFF/Driver.cpp

@@ -2557,14 +2557,14 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
         // it.
         if (symtab.findUnderscore("_load_config_used"))
           symtab.addGCRoot(symtab.mangle("_load_config_used"));
-      });
 
-      if (args.hasArg(OPT_include_optional)) {
-        // Handle /includeoptional
-        for (auto *arg : args.filtered(OPT_include_optional))
-          if (isa_and_nonnull<LazyArchive>(ctx.symtab.find(arg->getValue())))
-            ctx.symtab.addGCRoot(arg->getValue());
-      }
+        if (args.hasArg(OPT_include_optional)) {
+          // Handle /includeoptional
+          for (auto *arg : args.filtered(OPT_include_optional))
+            if (isa_and_nonnull<LazyArchive>(symtab.find(arg->getValue())))
+              symtab.addGCRoot(arg->getValue());
+        }
+      });
     } while (run());
   }
 

lld/test/COFF/arm64x-includeoptional.s

@@ -0,0 +1,17 @@
+// REQUIRE: aarch64
+
+// RUN: llvm-mc -filetype=obj -triple=aarch64-windows %s -o %t.arm64.obj
+// RUN: llvm-mc -filetype=obj -triple=arm64ec-windows %s -o %t.arm64ec.obj
+// RUN: llvm-mc -filetype=obj -triple=arm64ec-windows %S/Inputs/loadconfig-arm64ec.s -o %t-loadconfig-arm64ec.obj
+// RUN: llvm-mc -filetype=obj -triple=aarch64-windows %S/Inputs/loadconfig-arm64.s -o %t-loadconfig-arm64.obj
+
+// RUN: llvm-lib -machine:arm64x -out:%t-test.lib %t.arm64.obj %t.arm64ec.obj %t-loadconfig-arm64ec.obj %t-loadconfig-arm64.obj
+// RUN: lld-link -machine:arm64x -dll -noentry -out:%t.dll %t-test.lib -includeoptional:sym
+
+// RUN: llvm-readobj --hex-dump=.test %t.dll | FileCheck %s
+// CHECK: 0x180004000 01000000 01000000
+
+        .globl sym
+        .section .test,"dr"
+sym:
+        .word 1