[clang-cl] Add /Zc:wchar_t- option

[pzheng]

Summary

Map /Zc:wchar_t- to the cc1 flag -fno-wchar which is already supported.

[thakis]

Seems generally ok.

clang/include/clang/Driver/Options.td

6680–6681

Can you move this up (next to the - flag), and add a help text? It's no longer ignored now (if you do e.g. /Zc:wchar_t- /Zc:wchar_t)

[pzheng]

Address @thakis's comment

[pzheng]

clang/include/clang/Driver/Options.td

6680–6681

Thanks for the comment, @thakis. I have made the change accordingly.

[hans]

clang/test/Driver/cl-zc.cpp

50

Should probably remove /Zc:wchar_t from the list of ignored options in clang/test/Driver/cl-options.c too.

[thakis]

Looks good to me after addressing Hans's comment.

Do you have commit access?

[pzheng]

Address @hans's comment

[pzheng]

clang/test/Driver/cl-zc.cpp

50

Good catch. I have updated clang/test/Driver/cl-options.c in the latest change.

[pzheng]

In D125513#3519200, @thakis wrote:

Looks good to me after addressing Hans's comment.

Do you have commit access?

Thanks for asking, @thakis. I do have comment access.

clang/include/clang/Driver/Options.td

 def _SLASH_Zc_trigraphs_off : CLFlag<"Zc:trigraphs-">,
   HelpText<"Disable trigraphs (default)">, Alias<fno_trigraphs>;
 def _SLASH_Zc_twoPhase : CLFlag<"Zc:twoPhase">,
   HelpText<"Enable two-phase name lookup in templates">,
   Alias<fno_delayed_template_parsing>;
 def _SLASH_Zc_twoPhase_ : CLFlag<"Zc:twoPhase-">,
   HelpText<"Disable two-phase name lookup in templates (default)">,
   Alias<fdelayed_template_parsing>;
+def _SLASH_Zc_wchar_t : CLFlag<"Zc:wchar_t">,
+  HelpText<"Enable C++ builtin type wchar_t (default)">;
+def _SLASH_Zc_wchar_t_ : CLFlag<"Zc:wchar_t-">,
+  HelpText<"Disable C++ builtin type wchar_t">;
 def _SLASH_Z7 : CLFlag<"Z7">,
   HelpText<"Enable CodeView debug information in object files">;
 def _SLASH_Zi : CLFlag<"Zi">, Alias<_SLASH_Z7>,
   HelpText<"Like /Z7">;
 def _SLASH_Zp : CLJoined<"Zp">,
   HelpText<"Set default maximum struct packing alignment">,
   Alias<fpack_struct_EQ>;
 def _SLASH_Zp_flag : CLFlag<"Zp">,
def _SLASH_utf8 : CLIgnoredFlag<"utf-8">,
   HelpText<"Set source and runtime encoding to UTF-8 (default)">;
 def _SLASH_w : CLIgnoredJoined<"w">;
 def _SLASH_Wv_ : CLIgnoredJoined<"Wv">;
 def _SLASH_Zc___cplusplus : CLIgnoredFlag<"Zc:__cplusplus">;
 def _SLASH_Zc_auto : CLIgnoredFlag<"Zc:auto">;
 def _SLASH_Zc_forScope : CLIgnoredFlag<"Zc:forScope">;
 def _SLASH_Zc_inline : CLIgnoredFlag<"Zc:inline">;
 def _SLASH_Zc_rvalueCast : CLIgnoredFlag<"Zc:rvalueCast">;
 def _SLASH_Zc_ternary : CLIgnoredFlag<"Zc:ternary">;
-def _SLASH_Zc_wchar_t : CLIgnoredFlag<"Zc:wchar_t">;
 def _SLASH_ZH_MD5 : CLIgnoredFlag<"ZH:MD5">;
 def _SLASH_ZH_SHA1 : CLIgnoredFlag<"ZH:SHA1">;
 def _SLASH_ZH_SHA_256 : CLIgnoredFlag<"ZH:SHA_256">;
 def _SLASH_Zm : CLIgnoredJoined<"Zm">;
 def _SLASH_Zo : CLIgnoredFlag<"Zo">;
 def _SLASH_Zo_ : CLIgnoredFlag<"Zo-">;
 
 
 // Unsupported:

clang/lib/Driver/ToolChains/Clang.cpp

if (VolatileOptionID == options::OPT__SLASH_volatile_ms)
     CmdArgs.push_back("-fms-volatile");
 
  if (Args.hasFlag(options::OPT__SLASH_Zc_dllexportInlines_,
                   options::OPT__SLASH_Zc_dllexportInlines,
                   false)) {
   CmdArgs.push_back("-fno-dllexport-inlines");
  }
 
+ if (Args.hasFlag(options::OPT__SLASH_Zc_wchar_t_,
+                  options::OPT__SLASH_Zc_wchar_t, false)) {
+   CmdArgs.push_back("-fno-wchar");
+ }
+
   Arg *MostGeneralArg = Args.getLastArg(options::OPT__SLASH_vmg);
   Arg *BestCaseArg = Args.getLastArg(options::OPT__SLASH_vmb);
   if (MostGeneralArg && BestCaseArg)
     D.Diag(clang::diag::err_drv_argument_not_allowed_with)
         << MostGeneralArg->getAsString(Args) << BestCaseArg->getAsString(Args);
 
   if (MostGeneralArg) {
     Arg *SingleArg = Args.getLastArg(options::OPT__SLASH_vms);

clang/test/Driver/cl-zc.cpp

 // RUN: %clang_cl /c -### /Zc:forScope -- %s 2>&1 | FileCheck -check-prefix=FORSCOPE-ON %s
 // FORSCOPE-ON-NOT: argument unused during compilation
 // RUN: %clang_cl /c -### /Zc:forScope- -- %s 2>&1 | FileCheck -check-prefix=FORSCOPE-OFF %s
 // FORSCOPE-OFF: argument unused during compilation
 
 // RUN: %clang_cl /c -### /Zc:wchar_t -- %s 2>&1 | FileCheck -check-prefix=WCHAR_T-ON %s
 // WCHAR_T-ON-NOT: argument unused during compilation
 // RUN: %clang_cl /c -### /Zc:wchar_t- -- %s 2>&1 | FileCheck -check-prefix=WCHAR_T-OFF %s
-// WCHAR_T-OFF: argument unused during compilation
+// WCHAR_T-OFF: "-fno-wchar"
 
 // RUN: %clang_cl /c -### /Zc:auto -- %s 2>&1 | FileCheck -check-prefix=AUTO-ON %s
 // AUTO-ON-NOT: argument unused during compilation
 // RUN: %clang_cl /c -### /Zc:auto- -- %s 2>&1 | FileCheck -check-prefix=AUTO-OFF %s
 // AUTO-OFF: argument unused during compilation
 
 // RUN: %clang_cl /c -### /Zc:inline -- %s 2>&1 | FileCheck -check-prefix=INLINE-ON %s
 // INLINE-ON-NOT: argument unused during compilation