[ARM][AArch64] Change -mharden-sls= to use err_drv_unsupported_option_argument

[MaskRay]

Summary

Update the diagnostic in D81404: the convention is to use
err_drv_unsupported_option_argument instead of adding a new diagnostic for every
option.

[pengfei]

This is also fine to me. I'll rebase on it if @nickdesaulniers accept this.

clang/include/clang/Basic/DiagnosticDriverKinds.td

 def warn_ignoring_verify_debuginfo_preserve_export : Warning<
   "ignoring -fverify-debuginfo-preserve-export=%0 because "
   "-fverify-debuginfo-preserve wasn't enabled">,
   InGroup<UnusedCommandLineArgument>;
 def err_invalid_branch_protection: Error <
   "invalid branch protection option '%0' in '%1'">;
 def warn_unsupported_branch_protection: Warning <
   "invalid branch protection option '%0' in '%1'">, InGroup<BranchProtection>;
-def err_invalid_sls_hardening : Error<
-  "invalid sls hardening option '%0' in '%1'">;
 def err_sls_hardening_arm_not_supported : Error<
   "-mharden-sls is only supported on armv7-a or later">;
 
 def note_drv_command_failed_diag_msg : Note<
   "diagnostic msg: %0">;
 def note_drv_t_option_is_global : Note<
   "the last '/TC' or '/TP' option takes precedence over earlier instances">;
 def note_drv_address_sanitizer_debug_runtime : Note<

clang/lib/Driver/ToolChains/Arch/AArch64.cpp

if (Scope != "none") {
         if (Opt == "comdat") {
           DisableComdat = false;
           continue;
         }
         if (Opt == "nocomdat") {
           DisableComdat = true;
           continue;
         }
-        D.Diag(diag::err_invalid_sls_hardening)
-            << Scope << A->getAsString(Args);
+        D.Diag(diag::err_drv_unsupported_option_argument)
+            << A->getOption().getName() << Scope;
         break;
       }
     }
 
     if (EnableRetBr)
       Features.push_back("+harden-sls-retbr");
     if (EnableBlr)
       Features.push_back("+harden-sls-blr");

clang/lib/Driver/ToolChains/Arch/ARM.cpp

if (Scope != "none") {
         if (Opt == "comdat") {
           DisableComdat = false;
           continue;
         }
         if (Opt == "nocomdat") {
           DisableComdat = true;
           continue;
         }
-        D.Diag(diag::err_invalid_sls_hardening)
-            << Scope << A->getAsString(Args);
+        D.Diag(diag::err_drv_unsupported_option_argument)
+            << A->getOption().getName() << Scope;
         break;
       }
     }
 
     if (EnableRetBr || EnableBlr)
       if (!(isARMAProfile(Triple) && getARMSubArchVersionNumber(Triple) >= 7))
         D.Diag(diag::err_sls_hardening_arm_not_supported)
             << Scope << A->getAsString(Args);

clang/test/Driver/sls-hardening-options.c

 // RETBR-ON:  "+harden-sls-retbr"
 
 // BLR-OFF-NOT: "harden-sls-blr"
 // BLR-ON:  "+harden-sls-blr"
 
 // NOCOMDAT-OFF-NOT: "harden-sls-nocomdat"
 // NOCOMDAT: "+harden-sls-nocomdat"
 
-// BAD-SLS-SPEC: invalid sls hardening option '{{[^']+}}' in '-mharden-sls=
+// BAD-SLS-SPEC: unsupported argument '{{[^']+}}' to option '-mharden-sls='
 
 // RUN: %clang -target armv6a--none-eabi -c %s -### -mharden-sls=all 2>&1 | \
 // RUN: FileCheck %s --check-prefix=SLS-NOT-SUPPORTED
 
 // RUN: %clang -target armv6a--none-eabi -c %s -### -mharden-sls=retbr 2>&1 | \
 // RUN: FileCheck %s --check-prefix=SLS-NOT-SUPPORTED
 
 // RUN: %clang -target armv6a--none-eabi -c %s -### -mharden-sls=blr 2>&1 | \