[clang-cl] Add warning for /Zc:dllexportInlines- when the flag is used with /fallback

[takuto.ikuta]

Summary

This is followup of
https://reviews.llvm.org/D51340

[takuto.ikuta]

Inlines

[hans]

clang/lib/Driver/ToolChains/Clang.cpp

5507 ↗

(On Diff #173286)

I think the check should be with the code that handles /fallback, in visualstudio::Compiler::GetCommand, instead.

[takuto.ikuta]

warn in GetCommand

[takuto.ikuta]

Thank you for review!

[hans]

lgtm

include/clang/Basic/DiagnosticDriverKinds.td

def warn_drv_ycyu_different_arg_clang_cl : Warning<
   InGroup<ClangClPch>;
 def warn_drv_ycyu_no_fi_arg_clang_cl : Warning<
   "support for '%0' without a corresponding /FI flag not implemented yet; flag ignored">,
   InGroup<ClangClPch>;
 def warn_drv_yc_multiple_inputs_clang_cl : Warning<
   "support for '/Yc' with more than one source file not implemented yet; flag ignored">,
   InGroup<ClangClPch>;
 
+def warn_drv_non_fallback_argument_clang_cl : Warning<
+  "option '%0' is ignored when /fallback happens">,
+  InGroup<OptionIgnored>;
+
 def err_drv_invalid_value : Error<"invalid value '%1' in '%0'">;
 def err_drv_invalid_int_value : Error<"invalid integral value '%1' in '%0'">;
 def err_drv_invalid_remap_file : Error<
     "invalid option '%0' not of the form <from-file>;<to-file>">;
 def err_drv_invalid_gcc_output_type : Error<
     "invalid output type '%0' for use with gcc tool">;
 def err_drv_cc_print_options_failure : Error<
     "unable to open CC_PRINT_OPTIONS file: %0">;

lib/Driver/ToolChains/MSVC.cpp

CmdArgs.push_back(A->getOption().getID() == options::OPT_fthreadsafe_statics
                           ? "/Zc:threadSafeInit"
                           : "/Zc:threadSafeInit-");
   }
 
   // Pass through all unknown arguments so that the fallback command can see
   // them too.
   Args.AddAllArgs(CmdArgs, options::OPT_UNKNOWN);
 
+  // Warning for ignored flag.
+  if (const Arg *dllexportInlines =
+      Args.getLastArg(options::OPT__SLASH_Zc_dllexportInlines_))
+    C.getDriver().Diag(clang::diag::warn_drv_non_fallback_argument_clang_cl)
+      << dllexportInlines->getAsString(Args);
+
   // Input filename.
   assert(Inputs.size() == 1);
   const InputInfo &II = Inputs[0];
   assert(II.getType() == types::TY_C || II.getType() == types::TY_CXX);
   CmdArgs.push_back(II.getType() == types::TY_C ? "/Tc" : "/Tp");
   if (II.isFilename())
     CmdArgs.push_back(II.getFilename());
   else

test/Driver/cl-options.c

 
 // RUN: %clang_cl /Zc:threadSafeInit /c -### -- %s 2>&1 | FileCheck -check-prefix=ThreadSafeStatics %s
 // ThreadSafeStatics-NOT: "-fno-threadsafe-statics"
 
 // RUN: %clang_cl /Zc:dllexportInlines- /c -### -- %s 2>&1 | FileCheck -check-prefix=NoDllExportInlines %s
 // NoDllExportInlines: "-fno-dllexport-inlines"
 // RUN: %clang_cl /Zc:dllexportInlines /c -### -- %s 2>&1 | FileCheck -check-prefix=DllExportInlines %s
 // DllExportInlines-NOT: "-fno-dllexport-inlines"
+// RUN: %clang_cl /fallback /Zc:dllexportInlines- /c -### -- %s 2>&1 | FileCheck -check-prefix=DllExportInlinesFallback %s
+// DllExportInlinesFallback: warning: option '/Zc:dllexportInlines-' is ignored when /fallback happens [-Woption-ignored]
 
 // RUN: %clang_cl /Zi /c -### -- %s 2>&1 | FileCheck -check-prefix=Zi %s
 // Zi: "-gcodeview"
 // Zi: "-debug-info-kind=limited"
 
 // RUN: %clang_cl /Z7 /c -### -- %s 2>&1 | FileCheck -check-prefix=Z7 %s
 // Z7: "-gcodeview"
 // Z7: "-debug-info-kind=limited"