[Gnu] Ignore unknown arguments, and print message.

llvm-svn: 195597

lld/lib/Driver/GnuLdDriver.cpp

@@ -160,6 +160,13 @@ bool GnuLdDriver::parse(int argc, const char *argv[],
 
   int index = 0;
 
+  // Ignore unknown arguments.
+  for (auto it = parsedArgs->filtered_begin(OPT_UNKNOWN),
+            ie = parsedArgs->filtered_end();
+       it != ie; ++it)
+    diagnostics << "warning: ignoring unknown argument: " << (*it)->getValue()
+                << "\n";
+
   // Set sys root path.
   if (llvm::opt::Arg *sysRootPath = parsedArgs->getLastArg(OPT_sysroot))
     ctx->setSysroot(sysRootPath->getValue());

lld/test/elf/ignore-unknownoption.test

@@ -0,0 +1,5 @@
+# This test tests that lld is able to print unknown options that are not
+# recognized.
+RUN: not lld -flavor gnu -target x86_64 --gc-sections 2> %t
+RUN: FileCheck %s < %t
+CHECK: warning: ignoring unknown argument: --gc-sections