Allow C99 hexfloats in C++0x mode. This change resolves the standards

collision between C99 hexfloats and C++0x user-defined literals by
giving C99 hexfloats precedence. Also, warning about user-defined
literals that conflict with hexfloats and those that have names that
are reserved by the implementation. Fixes <rdar://problem/9940194>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138839 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 24 insertions, 0 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index cd4023eeda..df0a5226c0 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -9048,6 +9048,30 @@ FinishedParams:
     return true;
   }
 
+  StringRef LiteralName 
+    = FnDecl->getDeclName().getCXXLiteralIdentifier()->getName();
+  if (LiteralName[0] != '_') {
+    // C++0x [usrlit.suffix]p1:
+    //   Literal suffix identifiers that do not start with an underscore are 
+    //   reserved for future standardization.
+    bool IsHexFloat = true;
+    if (LiteralName.size() > 1 && 
+        (LiteralName[0] == 'P' || LiteralName[0] == 'p')) {
+      for (unsigned I = 1, N = LiteralName.size(); I < N; ++I) {
+        if (!isdigit(LiteralName[I])) {
+          IsHexFloat = false;
+          break;
+        }
+      }
+    }
+    
+    if (IsHexFloat)
+      Diag(FnDecl->getLocation(), diag::warn_user_literal_hexfloat)
+        << LiteralName;
+    else
+      Diag(FnDecl->getLocation(), diag::warn_user_literal_reserved);
+  }
+  
   return false;
 }