[LLD][COFF] Pull _load_config_used symbol from both symbol tables on ARM64X (#122837)

Author: cjacek

lld/COFF/Driver.cpp

@@ -2571,9 +2571,12 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
           ctx.symtab.addLibcall(s);
       }
 
-      // Windows specific -- if __load_config_used can be resolved, resolve it.
-      if (ctx.symtab.findUnderscore("_load_config_used"))
-        ctx.symtab.addGCRoot(ctx.symtab.mangle("_load_config_used"));
+      ctx.forEachSymtab([&](SymbolTable &symtab) {
+        // Windows specific -- if __load_config_used can be resolved, resolve
+        // it.
+        if (symtab.findUnderscore("_load_config_used"))
+          symtab.addGCRoot(symtab.mangle("_load_config_used"));
+      });
 
       if (args.hasArg(OPT_include_optional)) {
         // Handle /includeoptional

lld/test/COFF/arm64x-loadconfig.s

@@ -7,6 +7,7 @@
 // RUN: llvm-mc -filetype=obj -triple=arm64ec-windows loadconfig-ec.s -o loadconfig-ec.obj
 // RUN: llvm-mc -filetype=obj -triple=aarch64-windows loadconfig-short.s -o loadconfig-short.obj
 // RUN: llvm-mc -filetype=obj -triple=arm64ec-windows loadconfig-short.s -o loadconfig-short-arm64ec.obj
+// RUN: llvm-lib -machine:arm64x -out:loadconfig.lib loadconfig.obj loadconfig-ec.obj
 
 // RUN: lld-link -machine:arm64x -out:out-warn.dll -dll -noentry test.obj \
 // RUN:           2>&1 | FileCheck --check-prefixes=WARN-LOADCFG,WARN-EC-LOADCFG %s
@@ -158,6 +159,10 @@
 // BASERELOC-NEXT:     Address: 0x2074
 // BASERELOC-NEXT:   }
 
+// RUN: lld-link -machine:arm64x -out:out-hyb-lib.dll -dll -noentry loadconfig.lib chpe.obj test.obj
+// RUN: llvm-readobj --coff-load-config out-hyb-lib.dll | FileCheck --check-prefix=LOADCFG %s
+// RUN: llvm-readobj --coff-basereloc out-hyb-lib.dll | FileCheck --check-prefix=BASERELOC %s
+
 #--- test.s
         .data
 sym: