[coroutines] Add lexer support for co_await, co_yield, and co_return keywords.

Add -fcoroutines flag (just for -cc1 for now) to enable the feature. Early
indications are that this will be part of -std=c++1z.

llvm-svn: 250980

clang/include/clang/Basic/LangOptions.def

@@ -118,6 +118,7 @@ LANGOPT(Freestanding, 1, 0, "freestanding implementation")
 LANGOPT(NoBuiltin         , 1, 0, "disable builtin functions")
 LANGOPT(NoMathBuiltin     , 1, 0, "disable math builtin functions")
 LANGOPT(GNUAsm            , 1, 1, "GNU-style inline assembly")
+LANGOPT(Coroutines        , 1, 0, "C++ coroutines TS")
 
 BENIGN_LANGOPT(ThreadsafeStatics , 1, 1, "thread-safe static initializers")
 LANGOPT(POSIXThreads      , 1, 0, "POSIX thread support")

clang/include/clang/Basic/TokenKinds.def

@@ -242,6 +242,8 @@ PUNCTUATOR(greatergreatergreater, ">>>")
 //   KEYZVECTOR - This is a keyword for the System z vector extensions,
 //                which are heavily based on AltiVec
 //   KEYBORLAND - This is a keyword if Borland extensions are enabled
+//   KEYCOROUTINES - This is a keyword if support for the C++ coroutines
+//                   TS is enabled
 //   BOOLSUPPORT - This is a keyword if 'bool' is a built-in type
 //   HALFSUPPORT - This is a keyword if 'half' is a built-in type
 //   WCHARSUPPORT - This is a keyword if 'wchar_t' is a built-in type
@@ -356,6 +358,11 @@ CXX11_KEYWORD(thread_local          , 0)
 CONCEPTS_KEYWORD(concept)
 CONCEPTS_KEYWORD(requires)
 
+// C++ coroutines TS keywords
+KEYWORD(co_await                    , KEYCOROUTINES)
+KEYWORD(co_return                   , KEYCOROUTINES)
+KEYWORD(co_yield                    , KEYCOROUTINES)
+
 // GNU Extensions (in impl-reserved namespace)
 KEYWORD(_Decimal32                  , KEYALL)
 KEYWORD(_Decimal64                  , KEYALL)

clang/include/clang/Driver/CC1Options.td

@@ -580,6 +580,10 @@ def fnative_half_type: Flag<["-"], "fnative-half-type">,
 def fallow_half_arguments_and_returns : Flag<["-"], "fallow-half-arguments-and-returns">,
   HelpText<"Allow function arguments and returns of type half">;
 
+// C++ TSes.
+def fcoroutines : Flag<["-"], "fcoroutines">,
+  HelpText<"Enable support for the C++ Coroutines TS">;
+
 //===----------------------------------------------------------------------===//
 // Header Search Options
 //===----------------------------------------------------------------------===//

clang/lib/Basic/IdentifierTable.cpp

@@ -111,7 +111,8 @@ namespace {
     KEYCONCEPTS = 0x10000,
     KEYOBJC2    = 0x20000,
     KEYZVECTOR  = 0x40000,
-    KEYALL = (0x7ffff & ~KEYNOMS18 &
+    KEYCOROUTINES = 0x80000,
+    KEYALL = (0xfffff & ~KEYNOMS18 &
               ~KEYNOOPENCL) // KEYNOMS18 and KEYNOOPENCL are used to exclude.
   };
 
@@ -147,6 +148,7 @@ static KeywordStatus getKeywordStatus(const LangOptions &LangOpts,
   if (LangOpts.ObjC2 && (Flags & KEYARC)) return KS_Enabled;
   if (LangOpts.ConceptsTS && (Flags & KEYCONCEPTS)) return KS_Enabled;
   if (LangOpts.ObjC2 && (Flags & KEYOBJC2)) return KS_Enabled;
+  if (LangOpts.Coroutines && (Flags & KEYCOROUTINES)) return KS_Enabled;
   if (LangOpts.CPlusPlus && (Flags & KEYCXX11)) return KS_Future;
   return KS_Disabled;
 }

clang/lib/Frontend/CompilerInvocation.cpp

@@ -1536,6 +1536,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.RTTIData = Opts.RTTI && !Args.hasArg(OPT_fno_rtti_data);
   Opts.Blocks = Args.hasArg(OPT_fblocks);
   Opts.BlocksRuntimeOptional = Args.hasArg(OPT_fblocks_runtime_optional);
+  Opts.Coroutines = Args.hasArg(OPT_fcoroutines);
   Opts.Modules = Args.hasArg(OPT_fmodules);
   Opts.ModulesStrictDeclUse = Args.hasArg(OPT_fmodules_strict_decluse);
   Opts.ModulesDeclUse =