Fixed warnings on redefine keywords and reserved ids.

Repared support for warnings -Wkeyword-macro and -Wreserved-id-macro.
The warning -Wkeyword-macro now is not issued in patterns that are used
in configuration scripts:

    #define inline

also for 'const', 'extern' and 'static'. If macro repalcement is identical
to macro name, the warning also is not issued:

    #define volatile volatile

And finally if macro replacement is also a keyword identical to the replaced
one but decorated with leading/trailing underscores:

    #define inline __inline
    #define inline __inline__
    #define inline _inline // in MSVC compatibility mode

Warning -Wreserved-id-macro is off by default, it could help catching
things like:

    #undef __cplusplus


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@224512 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 14 insertions, 3 deletions

diff --git a/include/clang/Basic/DiagnosticGroups.td b/include/clang/Basic/DiagnosticGroups.td
index 81efb8eac9..f684ce9d5c 100644
--- a/include/clang/Basic/DiagnosticGroups.td
+++ b/include/clang/Basic/DiagnosticGroups.td
@@ -338,6 +338,7 @@ def : DiagGroup<"sequence-point", [Unsequenced]>;
 // Preprocessor warnings.
 def AmbiguousMacro : DiagGroup<"ambiguous-macro">;
 def KeywordAsMacro : DiagGroup<"keyword-macro">;
+def ReservedIdAsMacro : DiagGroup<"reserved-id-macro">;
 
 // Just silence warnings about -Wstrict-aliasing for now.
 def : DiagGroup<"strict-aliasing=0">;
diff --git a/include/clang/Basic/DiagnosticLexKinds.td b/include/clang/Basic/DiagnosticLexKinds.td
index 65f9f77af4..b9461c1a83 100644
--- a/include/clang/Basic/DiagnosticLexKinds.td
+++ b/include/clang/Basic/DiagnosticLexKinds.td
@@ -292,6 +292,9 @@ def note_pp_ambiguous_macro_other : Note<
   "other definition of %0">;
 def warn_pp_macro_hides_keyword : Extension<
   "keyword is hidden by macro definition">, InGroup<KeywordAsMacro>;
+def warn_pp_macro_is_reserved_id : Warning<
+  "macro name is a reserved identifier">, DefaultIgnore,
+  InGroup<ReservedIdAsMacro>;
 
 def pp_invalid_string_literal : Warning<
   "invalid string literal, ignoring final '\\'">;
diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index b6dcaa096b..326f519e91 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -1380,7 +1380,8 @@ public:
   /// followed by EOD.  Return true if the token is not a valid on-off-switch.
   bool LexOnOffSwitch(tok::OnOffSwitch &OOS);
 
-  bool CheckMacroName(Token &MacroNameTok, MacroUse isDefineUndef);
+  bool CheckMacroName(Token &MacroNameTok, MacroUse isDefineUndef,
+                      bool *ShadowFlag = nullptr);
 
 private:
 
@@ -1420,11 +1421,17 @@ private:
                                                              bool isPublic);
 
   /// \brief Lex and validate a macro name, which occurs after a
-  /// \#define or \#undef. 
+  /// \#define or \#undef.
+  ///
+  /// \param MacroNameTok Token that represents the name defined or undefined.
+  /// \param IsDefineUndef Kind if preprocessor directive.
+  /// \param ShadowFlag Points to flag that is set if macro name shadows
+  ///                   a keyword.
   ///
   /// This emits a diagnostic, sets the token kind to eod,
   /// and discards the rest of the macro line if the macro name is invalid.
-  void ReadMacroName(Token &MacroNameTok, MacroUse isDefineUndef = MU_Other);
+  void ReadMacroName(Token &MacroNameTok, MacroUse IsDefineUndef = MU_Other,
+                     bool *ShadowFlag = nullptr);
 
   /// The ( starting an argument list of a macro definition has just been read.
   /// Lex the rest of the arguments and the closing ), updating \p MI with