Add -Wc++11-compat warning for string and character literals followed by

identifiers, in cases where those identifiers would be treated as
user-defined literal suffixes in C++11.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@152198 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 25 insertions, 5 deletions

diff --git a/include/clang/Basic/DiagnosticLexKinds.td b/include/clang/Basic/DiagnosticLexKinds.td
index 776568f076..d31a48b656 100644
--- a/include/clang/Basic/DiagnosticLexKinds.td
+++ b/include/clang/Basic/DiagnosticLexKinds.td
@@ -131,6 +131,9 @@ def warn_ucn_not_valid_in_c89 : ExtWarn<
 def warn_cxx98_compat_unicode_literal : Warning<
   "unicode literals are incompatible with C++98">,
   InGroup<CXX98Compat>, DefaultIgnore;
+def warn_cxx11_compat_user_defined_literal : Warning<
+  "identifier after literal will be treated as a user-defined literal suffix "
+  "in C++11">, InGroup<CXX11Compat>, DefaultIgnore;
 def err_unsupported_string_concat : Error<
   "unsupported non-standard concatenation of string literals">;
 def err_string_concat_mixed_suffix : Error<
diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index a7fba8019d..0d388c6d01 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -1574,14 +1574,21 @@ void Lexer::LexNumericConstant(Token &Result, const char *CurPtr) {
 }
 
 /// LexUDSuffix - Lex the ud-suffix production for user-defined literal suffixes
-/// in C++11.
+/// in C++11, or warn on a ud-suffix in C++98.
 const char *Lexer::LexUDSuffix(Token &Result, const char *CurPtr) {
-  assert(getFeatures().CPlusPlus0x && "ud-suffix only exists in C++11");
+  assert(getFeatures().CPlusPlus);
 
   // Maximally munch an identifier. FIXME: UCNs.
   unsigned Size;
   char C = getCharAndSize(CurPtr, Size);
   if (isIdentifierHead(C)) {
+    if (!getFeatures().CPlusPlus0x) {
+      if (!isLexingRawMode())
+        Diag(CurPtr, diag::warn_cxx11_compat_user_defined_literal)
+          << FixItHint::CreateInsertion(getSourceLocation(CurPtr), " ");
+      return CurPtr;
+    }
+
     Result.setFlag(Token::HasUDSuffix);
     do {
       CurPtr = ConsumeChar(CurPtr, Size, Result);
@@ -1631,7 +1638,7 @@ void Lexer::LexStringLiteral(Token &Result, const char *CurPtr,
   }
 
   // If we are in C++11, lex the optional ud-suffix.
-  if (getFeatures().CPlusPlus0x)
+  if (getFeatures().CPlusPlus)
     CurPtr = LexUDSuffix(Result, CurPtr);
 
   // If a nul character existed in the string, warn about it.
@@ -1714,7 +1721,7 @@ void Lexer::LexRawStringLiteral(Token &Result, const char *CurPtr,
   }
 
   // If we are in C++11, lex the optional ud-suffix.
-  if (getFeatures().CPlusPlus0x)
+  if (getFeatures().CPlusPlus)
     CurPtr = LexUDSuffix(Result, CurPtr);
 
   // Update the location of token as well as BufferPtr.
@@ -1801,7 +1808,7 @@ void Lexer::LexCharConstant(Token &Result, const char *CurPtr,
   }
 
   // If we are in C++11, lex the optional ud-suffix.
-  if (getFeatures().CPlusPlus0x)
+  if (getFeatures().CPlusPlus)
     CurPtr = LexUDSuffix(Result, CurPtr);
 
   // If a nul character existed in the character, warn about it.
diff --git a/test/SemaCXX/cxx0x-compat.cpp b/test/SemaCXX/cxx0x-compat.cpp
index 1ae1c608c1..611dcc755e 100644
--- a/test/SemaCXX/cxx0x-compat.cpp
+++ b/test/SemaCXX/cxx0x-compat.cpp
@@ -27,3 +27,13 @@ struct S {
 }
 s = { n }, // expected-warning {{non-constant-expression cannot be narrowed from type 'int' to 'char' in initializer list in C++11}} expected-note {{explicit cast}}
 t = { 1234 }; // expected-warning {{constant expression evaluates to 1234 which cannot be narrowed to type 'char' in C++11}} expected-warning {{changes value}} expected-note {{explicit cast}}
+
+#define PRIuS "uS"
+int printf(const char *, ...);
+typedef __typeof(sizeof(int)) size_t;
+void h(size_t foo, size_t bar) {
+  printf("foo is %"PRIuS", bar is %"PRIuS, foo, bar); // expected-warning 2{{identifier after literal will be treated as a user-defined literal suffix in C++11}}
+}
+
+#define x + 1
+char c = 'x'x; // expected-warning {{will be treated as a user-defined literal suffix}}