Add a -Wc++0x-compat warning for C++11 keywords used as identifiers when in

C++98 mode. Only the first occurrence of each keyword will produce a warning.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@141700 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 21 insertions, 7 deletions

diff --git a/lib/Basic/IdentifierTable.cpp b/lib/Basic/IdentifierTable.cpp
index 2419f9bb6c..38f09a08af 100644
--- a/lib/Basic/IdentifierTable.cpp
+++ b/lib/Basic/IdentifierTable.cpp
@@ -32,6 +32,7 @@ IdentifierInfo::IdentifierInfo() {
   ObjCOrBuiltinID = 0;
   HasMacro = false;
   IsExtension = false;
+  IsCXX11CompatKeyword = false;
   IsPoisoned = false;
   IsCPPOperatorKeyword = false;
   NeedsHandleIdentifier = false;
@@ -102,10 +103,10 @@ namespace {
 /// identifiers because they are language keywords.  This causes the lexer to
 /// automatically map matching identifiers to specialized token codes.
 ///
-/// The C90/C99/CPP/CPP0x flags are set to 2 if the token should be
-/// enabled in the specified langauge, set to 1 if it is an extension
-/// in the specified language, and set to 0 if disabled in the
-/// specified language.
+/// The C90/C99/CPP/CPP0x flags are set to 3 if the token is a keyword in a
+/// future language standard, set to 2 if the token should be enabled in the
+/// specified langauge, set to 1 if it is an extension in the specified
+/// language, and set to 0 if disabled in the specified language.
 static void AddKeyword(StringRef Keyword,
                        tok::TokenKind TokenCode, unsigned Flags,
                        const LangOptions &LangOpts, IdentifierTable &Table) {
@@ -123,12 +124,15 @@ static void AddKeyword(StringRef Keyword,
   else if (!LangOpts.CPlusPlus && (Flags & KEYNOCXX)) AddResult = 2;
   else if (LangOpts.C1X && (Flags & KEYC1X)) AddResult = 2;
   else if (LangOpts.ObjCAutoRefCount && (Flags & KEYARC)) AddResult = 2;
-           
+  else if (LangOpts.CPlusPlus && (Flags & KEYCXX0X)) AddResult = 3;
+
   // Don't add this keyword if disabled in this language.
   if (AddResult == 0) return;
 
-  IdentifierInfo &Info = Table.get(Keyword, TokenCode);
+  IdentifierInfo &Info =
+      Table.get(Keyword, AddResult == 3 ? tok::identifier : TokenCode);
   Info.setIsExtensionToken(AddResult == 1);
+  Info.setIsCXX11CompatKeyword(AddResult == 3);
 }
 
 /// AddCXXOperatorKeyword - Register a C++ operator keyword alternative
@@ -493,4 +497,3 @@ const char *clang::getOperatorSpelling(OverloadedOperatorKind Operator) {
 
   return 0;
 }
-
diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp
index dee98eac40..31662ad0c1 100644
--- a/lib/Lex/Preprocessor.cpp
+++ b/lib/Lex/Preprocessor.cpp
@@ -513,6 +513,17 @@ void Preprocessor::HandleIdentifier(Token &Identifier) {
     }
   }
 
+  // If this identifier is a keyword in C++11, produce a warning. Don't warn if
+  // we're not considering macro expansion, since this identifier might be the
+  // name of a macro.
+  // FIXME: This warning is disabled in cases where it shouldn't be, like
+  //   "#define constexpr constexpr", "int constexpr;"
+  if (II.isCXX11CompatKeyword() & !DisableMacroExpansion) {
+    Diag(Identifier, diag::warn_cxx11_keyword) << II.getName();
+    // Don't diagnose this keyword again in this translation unit.
+    II.setIsCXX11CompatKeyword(false);
+  }
+
   // C++ 2.11p2: If this is an alternative representation of a C++ operator,
   // then we act as if it is the actual operator and not the textual
   // representation of it.