[Driver] Update set of -std values with C++20 modules enabled

[ilya-biryukov]

Summary

Previously missing are -std=gnu++2(0|a) and -std=(gnu|c)++2b.
This used to result in wrong -cc1 flags produced by Driver.

[sammccall]

LG, but can you change the patch description as you're bringing the set up to date rather than just adding gnu++20

clang/lib/Driver/ToolChains/Clang.cpp

if (Arg *A = Args.getLastArg(options::OPT_finline, options::OPT_fno_inline)) {
     if (A->getOption().matches(options::OPT_fno_inline))
       A->render(Args, CmdArgs);
   } else if (InlineArg) {
     InlineArg->render(Args, CmdArgs);
   }
 
   // FIXME: Find a better way to determine whether the language has modules
   // support by default, or just assume that all languages do.
-  bool HaveModules =
-      Std && (Std->containsValue("c++2a") || Std->containsValue("c++20") ||
-              Std->containsValue("c++latest"));
+  bool HaveModules = Std && llvm::any_of(Std->getValues(), [](const char *S) {
+                       constexpr llvm::StringRef CPP_MODULES_STD[] = {
+                           "c++2a",   "c++20",   "c++2b",  "c++latest",
+                           "gnu++2a", "gnu++20", "gnu++2b"};
+                       return llvm::is_contained(CPP_MODULES_STD, S);
+                     });
   RenderModulesOptions(C, D, Args, Input, Output, CmdArgs, HaveModules);
 
   if (Args.hasFlag(options::OPT_fpch_validate_input_files_content,
                    options::OPT_fno_pch_validate_input_files_content, false))
     CmdArgs.push_back("-fvalidate-ast-input-files-content");
   if (Args.hasFlag(options::OPT_fpch_instantiate_templates,
                    options::OPT_fno_pch_instantiate_templates, false))
     CmdArgs.push_back("-fpch-instantiate-templates");

clang/test/Driver/cpp20-header-module.cpp

 // Check header modules are not enabled with C++20 standard and -fmodules-ts.
 //
 // RUN: %clang -fmodules-ts -std=c++20 -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=NO_HEADER_MODULES
 // RUN: %clang -std=c++20 -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=NO_HEADER_MODULES
 // RUN: %clang -std=c++2a -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=NO_HEADER_MODULES
+// RUN: %clang -std=c++2b -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=NO_HEADER_MODULES
 // RUN: %clang_cl /std:c++latest /Zs -v %s 2>&1 | FileCheck %s --check-prefix=NO_HEADER_MODULES
+// RUN: %clang -std=gnu++20 -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=NO_HEADER_MODULES
+// RUN: %clang -std=gnu++2a -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=NO_HEADER_MODULES
+// RUN: %clang -std=gnu++2b -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=NO_HEADER_MODULES
 //
 // NO_HEADER_MODULES-NOT: -fheader-modules
 // NO_HEADER_MODULES: -cc1
 // NO_HEADER_MODULES-SAME: -fno-header-modules
 //
 // RUN: %clang -fmodules -fmodules-ts -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=HAS_HEADER_MODULES
 // RUN: %clang -fmodules -fmodules-ts -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=HAS_HEADER_MODULES
 // RUN: %clang -fmodules -std=c++20 -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=HAS_HEADER_MODULES
 // RUN: %clang -fmodules -std=c++2a -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=HAS_HEADER_MODULES
+// RUN: %clang -fmodules -std=c++2b -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=HAS_HEADER_MODULES
+// RUN: %clang -fmodules -std=gnu++20 -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=HAS_HEADER_MODULES
+// RUN: %clang -fmodules -std=gnu++2a -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=HAS_HEADER_MODULES
+// RUN: %clang -fmodules -std=gnu++2b -fsyntax-only -v %s 2>&1 | FileCheck %s --check-prefix=HAS_HEADER_MODULES
 //
 // HAS_HEADER_MODULES-NOT: -fno-header-modules
 // HAS_HEADER_MODULES: -cc1
 // HAS_HEADER_MODULES: -fheader-modules

clang/test/Modules/cxx20-and-header-modules.cpp

 // RUN: rm -rf %t
 //
 // Check header modules are disabled by default in C++20 mode.
 // RUN: %clang -std=c++20 -fsyntax-only -fno-implicit-modules -fmodules-cache-path=%t -I%S/Inputs/cxx20-and-header-modules -fmodule-map-file=%S/Inputs/cxx20-and-header-modules/a.map %s
+// RUN: %clang -std=gnu++20 -fsyntax-only -fno-implicit-modules -fmodules-cache-path=%t -I%S/Inputs/cxx20-and-header-modules -fmodule-map-file=%S/Inputs/cxx20-and-header-modules/a.map %s
 //
 // Also run in the header modules mode.
 // RUN: %clang -std=c++20 -DBUILDING_MODULE -fmodules -fimplicit-modules -fmodules-cache-path=%t -I%S/Inputs/cxx20-and-header-modules -fmodule-map-file=%S/Inputs/cxx20-and-header-modules/a.map %s
+// RUN: rm -rf %t
+// RUN: %clang -std=gnu++20 -DBUILDING_MODULE -fmodules -fimplicit-modules -fmodules-cache-path=%t -I%S/Inputs/cxx20-and-header-modules -fmodule-map-file=%S/Inputs/cxx20-and-header-modules/a.map %s
 
 #define INCLUDING 1
 #include "a.h"
 
 int main() {
   return X().foo();
 }