Index: lld/ELF/Config.h
===================================================================
--- lld/ELF/Config.h
+++ lld/ELF/Config.h
@@ -121,6 +121,7 @@
   llvm::StringRef thinLTOCacheDir;
   llvm::StringRef thinLTOIndexOnlyArg;
   llvm::StringRef ltoBasicBlockSections;
+  llvm::StringRef errorHandlingScript;
   std::pair<llvm::StringRef, llvm::StringRef> thinLTOObjectSuffixReplace;
   std::pair<llvm::StringRef, llvm::StringRef> thinLTOPrefixReplace;
   std::string rpath;
Index: lld/ELF/Driver.cpp
===================================================================
--- lld/ELF/Driver.cpp
+++ lld/ELF/Driver.cpp
@@ -54,6 +54,7 @@
 #include "llvm/Support/LEB128.h"
 #include "llvm/Support/Parallel.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/Program.h"
 #include "llvm/Support/TarWriter.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/TimeProfiler.h"
@@ -277,8 +278,20 @@
 void LinkerDriver::addLibrary(StringRef name) {
   if (Optional<std::string> path = searchLibrary(name))
     addFile(*path, /*withLOption=*/true);
-  else
-    error("unable to find library -l" + name);
+  else {
+    if (config->errorHandlingScript.empty()) {
+      error("unable to find library -l" + name);
+    } else {
+      int Res = llvm::sys::ExecuteAndWait(
+          config->errorHandlingScript,
+          {config->errorHandlingScript, "missing-symbol", name});
+      if (Res >= 0)
+        exitLld(1);
+      else
+        error("Failed to call error handling script: " +
+              config->errorHandlingScript);
+    }
+  }
 }
 
 // This function is called on startup. We need this for LTO since
@@ -901,6 +914,8 @@
   errorHandler().vsDiagnostics =
       args.hasArg(OPT_visual_studio_diagnostics_format, false);
 
+  config->errorHandlingScript = args.getLastArgValue(OPT_error_handling_script);
+
   config->allowMultipleDefinition =
       args.hasFlag(OPT_allow_multiple_definition,
                    OPT_no_allow_multiple_definition, false) ||
Index: lld/ELF/Options.td
===================================================================
--- lld/ELF/Options.td
+++ lld/ELF/Options.td
@@ -179,6 +179,10 @@
 def error_unresolved_symbols: F<"error-unresolved-symbols">,
   HelpText<"Report unresolved symbols as errors">;
 
+defm error_handling_script: Eq<"error-handling-script",
+    "Specify an error handling script">;
+
+
 defm exclude_libs: Eq<"exclude-libs", "Exclude static libraries from automatic export">;
 
 defm execute_only: BB<"execute-only",