[clang][cli] Store LangStandard::Kind in LangOptions

The `LangStandard::Kind` parsed from command line arguments is used to set up some `LangOption` defaults, but isn't stored anywhere.

To be able to generate `-std=` (in future patch), we need `CompilerInvocation` to not forget it.

This patch demonstrates another use-case: using `LangStd` to set up defaults of marshalled options.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D95342

Author: jansvoboda11

clang/include/clang/Basic/LangOptions.h

@@ -16,6 +16,7 @@
 
 #include "clang/Basic/CommentOptions.h"
 #include "clang/Basic/LLVM.h"
+#include "clang/Basic/LangStandard.h"
 #include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/Sanitizers.h"
 #include "clang/Basic/Visibility.h"
@@ -257,6 +258,9 @@ class LangOptions : public LangOptionsBase {
   };
 
 public:
+  /// The used language standard.
+  LangStandard::Kind LangStd;
+
   /// Set of enabled sanitizers.
   SanitizerSet Sanitize;
 

clang/include/clang/Driver/Options.td

@@ -434,8 +434,11 @@ class MarshallingInfoVisibility<KeyPathAndMacro kpm, code default>
     AutoNormalizeEnum {}
 
 // Key paths that are constant during parsing of options with the same key path prefix.
+defvar lang_std = LangOpts<"LangStd">;
 defvar open_cl = LangOpts<"OpenCL">;
 
+defvar std = !strconcat("LangStandard::getLangStandardForKind(", lang_std.KeyPath, ")");
+
 /////////
 // Options
 
@@ -1952,10 +1955,11 @@ def fno_common : Flag<["-"], "fno-common">, Group<f_Group>, Flags<[CC1Option]>,
     HelpText<"Compile common globals like normal definitions">;
 def fno_cxx_modules : Flag <["-"], "fno-cxx-modules">, Group<f_Group>,
   Flags<[NoXarchOption]>;
-def fdigraphs : Flag<["-"], "fdigraphs">, Group<f_Group>, Flags<[CC1Option]>,
-  HelpText<"Enable alternative token representations '<:', ':>', '<%', '%>', '%:', '%:%:' (default)">;
-def fno_digraphs : Flag<["-"], "fno-digraphs">, Group<f_Group>, Flags<[CC1Option]>,
-  HelpText<"Disallow alternative token representations '<:', ':>', '<%', '%>', '%:', '%:%:'">;
+defm digraphs : BoolFOption<"digraphs",
+  LangOpts<"Digraphs">, Default<std#".hasDigraphs()">,
+  PosFlag<SetTrue, [], "Enable alternative token representations '<:', ':>', '<%', '%>', '%:', '%:%:' (default)">,
+  NegFlag<SetFalse, [], "Disallow alternative token representations '<:', ':>', '<%', '%>', '%:', '%:%:'">,
+  BothFlags<[CC1Option]>>;
 def fno_declspec : Flag<["-"], "fno-declspec">, Group<f_clang_Group>,
   HelpText<"Disallow __declspec as a keyword">, Flags<[CC1Option]>;
 def fno_dollars_in_identifiers : Flag<["-"], "fno-dollars-in-identifiers">, Group<f_Group>,

clang/lib/Basic/LangOptions.cpp

@@ -14,7 +14,7 @@
 
 using namespace clang;
 
-LangOptions::LangOptions() {
+LangOptions::LangOptions() : LangStd(LangStandard::lang_unspecified) {
 #define LANGOPT(Name, Bits, Default, Description) Name = Default;
 #define ENUM_LANGOPT(Name, Type, Bits, Default, Description) set##Name(Default);
 #include "clang/Basic/LangOptions.def"

clang/lib/Frontend/CompilerInvocation.cpp

@@ -1971,6 +1971,7 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
   }
 
   const LangStandard &Std = LangStandard::getLangStandardForKind(LangStd);
+  Opts.LangStd = LangStd;
   Opts.LineComment = Std.hasLineComments();
   Opts.C99 = Std.isC99();
   Opts.C11 = Std.isC11();
@@ -1982,7 +1983,6 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
   Opts.CPlusPlus17 = Std.isCPlusPlus17();
   Opts.CPlusPlus20 = Std.isCPlusPlus20();
   Opts.CPlusPlus2b = Std.isCPlusPlus2b();
-  Opts.Digraphs = Std.hasDigraphs();
   Opts.GNUMode = Std.isGNUMode();
   Opts.GNUInline = !Opts.C99 && !Opts.CPlusPlus;
   Opts.GNUCVersion = 0;
@@ -2262,8 +2262,6 @@ void CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
   Opts.GNUKeywords = Args.hasFlag(OPT_fgnu_keywords, OPT_fno_gnu_keywords,
                                   Opts.GNUKeywords);
 
-  Opts.Digraphs = Args.hasFlag(OPT_fdigraphs, OPT_fno_digraphs, Opts.Digraphs);
-
   if (Args.hasArg(OPT_fno_operator_names))
     Opts.CXXOperatorNames = 0;
 

clang/unittests/Frontend/CompilerInvocationTest.cpp

@@ -695,4 +695,49 @@ TEST_F(CommandLineTest, DiagnosticOptionPresent) {
 
   ASSERT_THAT(GeneratedArgs, ContainsN(StrEq("-verify=xyz"), 1));
 }
+
+// Option default depends on language standard.
+
+TEST_F(CommandLineTest, DigraphsImplied) {
+  const char *Args[] = {""};
+
+  ASSERT_TRUE(CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags));
+  ASSERT_TRUE(Invocation.getLangOpts()->Digraphs);
+
+  Invocation.generateCC1CommandLine(GeneratedArgs, *this);
+  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fno-digraphs"))));
+  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fdigraphs"))));
+}
+
+TEST_F(CommandLineTest, DigraphsDisabled) {
+  const char *Args[] = {"-fno-digraphs"};
+
+  ASSERT_TRUE(CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags));
+  ASSERT_FALSE(Invocation.getLangOpts()->Digraphs);
+
+  Invocation.generateCC1CommandLine(GeneratedArgs, *this);
+  ASSERT_THAT(GeneratedArgs, Contains(StrEq("-fno-digraphs")));
+  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fdigraphs"))));
+}
+
+TEST_F(CommandLineTest, DigraphsNotImplied) {
+  const char *Args[] = {"-std=c89"};
+
+  ASSERT_TRUE(CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags));
+  ASSERT_FALSE(Invocation.getLangOpts()->Digraphs);
+
+  Invocation.generateCC1CommandLine(GeneratedArgs, *this);
+  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fno-digraphs"))));
+  ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("-fdigraphs"))));
+}
+
+TEST_F(CommandLineTest, DigraphsEnabled) {
+  const char *Args[] = {"-std=c89", "-fdigraphs"};
+
+  ASSERT_TRUE(CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags));
+  ASSERT_TRUE(Invocation.getLangOpts()->Digraphs);
+
+  Invocation.generateCC1CommandLine(GeneratedArgs, *this);
+  ASSERT_THAT(GeneratedArgs, Contains(StrEq("-fdigraphs")));
+}
 } // anonymous namespace