Add warning flag -Winvalid-pp-token for preprocessing-tokens which have

undefined behaviour, and move the diagnostic for '' from an Error into
an ExtWarn in this group. This is important for some users of the preprocessor,
and is necessary for gcc compatibility.

llvm-svn: 159335

5 files changed, 12 insertions, 10 deletions

diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index c98dfae6bc5..a99eb1d486d 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -217,6 +217,7 @@ def ImplicitFallthroughPerFunction :
   DiagGroup<"implicit-fallthrough-per-function">;
 def ImplicitFallthrough  : DiagGroup<"implicit-fallthrough",
                                      [ImplicitFallthroughPerFunction]>;
+def InvalidPPToken : DiagGroup<"invalid-pp-token">;
 def Trigraphs      : DiagGroup<"trigraphs">;
 
 def : DiagGroup<"type-limits">;
diff --git a/clang/include/clang/Basic/DiagnosticLexKinds.td b/clang/include/clang/Basic/DiagnosticLexKinds.td
index 464699fb911..77b7f428723 100644
--- a/clang/include/clang/Basic/DiagnosticLexKinds.td
+++ b/clang/include/clang/Basic/DiagnosticLexKinds.td
@@ -64,9 +64,12 @@ def ext_token_used : Extension<"extension used">,
 def warn_cxx11_keyword : Warning<"'%0' is a keyword in C++11">,
   InGroup<CXX11Compat>, DefaultIgnore;
 
-def warn_unterminated_string : ExtWarn<"missing terminating '\"' character">;
-def warn_unterminated_char : ExtWarn<"missing terminating ' character">;
-def err_empty_character : Error<"empty character constant">;
+def ext_unterminated_string : ExtWarn<"missing terminating '\"' character">,
+  InGroup<InvalidPPToken>;
+def ext_unterminated_char : ExtWarn<"missing terminating ' character">,
+  InGroup<InvalidPPToken>;
+def ext_empty_character : ExtWarn<"empty character constant">,
+  InGroup<InvalidPPToken>;
 def err_unterminated_block_comment : Error<"unterminated /* comment">;
 def err_invalid_character_to_charify : Error<
   "invalid argument to convert to character">;
diff --git a/clang/lib/Lex/Lexer.cpp b/clang/lib/Lex/Lexer.cpp
index dedf320013c..52a094af7f9 100644
--- a/clang/lib/Lex/Lexer.cpp
+++ b/clang/lib/Lex/Lexer.cpp
@@ -1649,7 +1649,7 @@ void Lexer::LexStringLiteral(Token &Result, const char *CurPtr,
     if (C == '\n' || C == '\r' ||             // Newline.
         (C == 0 && CurPtr-1 == BufferEnd)) {  // End of file.
       if (!isLexingRawMode() && !LangOpts.AsmPreprocessor)
-        Diag(BufferPtr, diag::warn_unterminated_string);
+        Diag(BufferPtr, diag::ext_unterminated_string);
       FormTokenWithChars(Result, CurPtr-1, tok::unknown);
       return;
     }
@@ -1807,7 +1807,7 @@ void Lexer::LexCharConstant(Token &Result, const char *CurPtr,
   char C = getAndAdvanceChar(CurPtr, Result);
   if (C == '\'') {
     if (!isLexingRawMode() && !LangOpts.AsmPreprocessor)
-      Diag(BufferPtr, diag::err_empty_character);
+      Diag(BufferPtr, diag::ext_empty_character);
     FormTokenWithChars(Result, CurPtr, tok::unknown);
     return;
   }
@@ -1821,7 +1821,7 @@ void Lexer::LexCharConstant(Token &Result, const char *CurPtr,
     } else if (C == '\n' || C == '\r' ||             // Newline.
                (C == 0 && CurPtr-1 == BufferEnd)) {  // End of file.
       if (!isLexingRawMode() && !LangOpts.AsmPreprocessor)
-        Diag(BufferPtr, diag::warn_unterminated_char);
+        Diag(BufferPtr, diag::ext_unterminated_char);
       FormTokenWithChars(Result, CurPtr-1, tok::unknown);
       return;
     } else if (C == 0) {
diff --git a/clang/test/Misc/warning-flags-enabled.c b/clang/test/Misc/warning-flags-enabled.c
index 1c1c38f864d..7ef5c94dbc8 100644
--- a/clang/test/Misc/warning-flags-enabled.c
+++ b/clang/test/Misc/warning-flags-enabled.c
@@ -3,9 +3,9 @@
 // This shows warnings which are on by default.
 // We just check a few to make sure it's doing something sensible.
 //
+// CHECK: ext_unterminated_string
 // CHECK: warn_condition_is_assignment
 // CHECK: warn_null_arg
-// CHECK: warn_unterminated_string
 
 
 // RUN: diagtool show-enabled -Wno-everything %s | count 0
diff --git a/clang/test/Misc/warning-flags.c b/clang/test/Misc/warning-flags.c
index 2799de584c3..3b28fd85d7f 100644
--- a/clang/test/Misc/warning-flags.c
+++ b/clang/test/Misc/warning-flags.c
@@ -17,7 +17,7 @@ This test serves two purposes:
 
 The list of warnings below should NEVER grow.  It should gradually shrink to 0.
 
-CHECK: Warnings without flags (232):
+CHECK: Warnings without flags (230):
 CHECK-NEXT:   ext_anonymous_struct_union_qualified
 CHECK-NEXT:   ext_binary_literal
 CHECK-NEXT:   ext_cast_fn_obj
@@ -245,8 +245,6 @@ CHECK-NEXT:   warn_undef_protocolref
 CHECK-NEXT:   warn_undefined_internal
 CHECK-NEXT:   warn_unknown_analyzer_checker
 CHECK-NEXT:   warn_unknown_method_family
-CHECK-NEXT:   warn_unterminated_char
-CHECK-NEXT:   warn_unterminated_string
 CHECK-NEXT:   warn_use_out_of_scope_declaration
 CHECK-NEXT:   warn_weak_identifier_undeclared
 CHECK-NEXT:   warn_weak_import