Pull in r166498 from upstream clang trunk:

Add a new warning -Wmissing-variable-declarations, to warn about variables
defined without a previous declaration.  This is similar to
-Wmissing-prototypes, but for variables instead of functions.

2 files changed, 13 insertions, 0 deletions

diff --git a/contrib/llvm/tools/clang/lib/Sema/Sema.cpp b/contrib/llvm/tools/clang/lib/Sema/Sema.cpp
index 7f79f0c..6e2de4d 100644
--- a/contrib/llvm/tools/clang/lib/Sema/Sema.cpp
+++ b/contrib/llvm/tools/clang/lib/Sema/Sema.cpp
@@ -648,6 +648,8 @@ void Sema::ActOnEndOfTranslationUnit() {
                                    diag::err_tentative_def_incomplete_type))
       VD->setInvalidDecl();
 
+    CheckCompleteVariableDeclaration(VD);
+
     // Notify the consumer that we've completed a tentative definition.
     if (!VD->isInvalidDecl())
       Consumer.CompleteTentativeDefinition(VD);
diff --git a/contrib/llvm/tools/clang/lib/Sema/SemaDecl.cpp b/contrib/llvm/tools/clang/lib/Sema/SemaDecl.cpp
index ea181de..ff1eb84 100644
--- a/contrib/llvm/tools/clang/lib/Sema/SemaDecl.cpp
+++ b/contrib/llvm/tools/clang/lib/Sema/SemaDecl.cpp
@@ -6957,6 +6957,17 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
     }
   }
 
+  if (var->isThisDeclarationADefinition() &&
+      var->getLinkage() == ExternalLinkage) {
+    // Find a previous declaration that's not a definition.
+    VarDecl *prev = var->getPreviousDecl();
+    while (prev && prev->isThisDeclarationADefinition())
+      prev = prev->getPreviousDecl();
+
+    if (!prev)
+      Diag(var->getLocation(), diag::warn_missing_variable_declarations) << var;
+  }
+
   // All the following checks are C++ only.
   if (!getLangOpts().CPlusPlus) return;