Check for unsupported target options even with -Qunused-arguments (#141698)

Fix clang accidentally skipping checks for
`err_drv_unsupported_opt_for_target` when `-Qunused-arguments` was
active.

Author: MatzeB

clang/lib/Driver/Driver.cpp

@@ -5362,11 +5362,11 @@ void Driver::BuildJobs(Compilation &C) const {
     });
   }
 
-  // If the user passed -Qunused-arguments or there were errors, don't warn
-  // about any unused arguments.
-  if (Diags.hasErrorOccurred() ||
-      C.getArgs().hasArg(options::OPT_Qunused_arguments))
-    return;
+  // If the user passed -Qunused-arguments or there were errors, don't
+  // warn about any unused arguments.
+  bool ReportUnusedArguments =
+      !Diags.hasErrorOccurred() &&
+      !C.getArgs().hasArg(options::OPT_Qunused_arguments);
 
   // Claim -fdriver-only here.
   (void)C.getArgs().hasArg(options::OPT_fdriver_only);
@@ -5420,7 +5420,7 @@ void Driver::BuildJobs(Compilation &C) const {
             !C.getActions().empty()) {
           Diag(diag::err_drv_unsupported_opt_for_target)
               << A->getSpelling() << getTargetTriple();
-        } else {
+        } else if (ReportUnusedArguments) {
           Diag(clang::diag::warn_drv_unused_argument)
               << A->getAsString(C.getArgs());
         }

clang/test/Driver/unsupported-option.c

@@ -27,3 +27,8 @@
 // RUN: not %clang --target=x86_64 -### -mhtm -lc %s 2>&1 \
 // RUN:   | FileCheck %s -check-prefix=UNSUP_OPT
 // UNSUP_OPT: error: unsupported option
+
+
+// RUN: not %clang -c -Qunused-arguments --target=aarch64-- -mfpu=crypto-neon-fp-armv8 %s 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=QUNUSED_ARGUMENTS
+// QUNUSED_ARGUMENTS: error: unsupported option '-mfpu=' for target 'aarch64--'