Merge in r167749, per discussion on cfe-dev that we want -Wimplicit-fallthrough to only be active for C++11

until we come up with a language annotation for this warning that works outside of C++11.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_32@167775 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 15 insertions, 0 deletions

diff --git a/lib/Sema/AnalysisBasedWarnings.cpp b/lib/Sema/AnalysisBasedWarnings.cpp
index a20817f965..801a1b1e02 100644
--- a/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/lib/Sema/AnalysisBasedWarnings.cpp
@@ -818,6 +818,18 @@ namespace {
 
 static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC,
                                             bool PerFunction) {
+  // Only perform this analysis when using C++11.  There is no good workflow
+  // for this warning when not using C++11.  There is no good way to silence
+  // the warning (no attribute is available) unless we are using C++11's support
+  // for generalized attributes.  Once could use pragmas to silence the warning,
+  // but as a general solution that is gross and not in the spirit of this
+  // warning.
+  //
+  // NOTE: This an intermediate solution.  There are on-going discussions on
+  // how to properly support this warning outside of C++11 with an annotation.
+  if (!AC.getASTContext().getLangOpts().CPlusPlus0x)
+    return;
+
   FallthroughMapper FM(S);
   FM.TraverseStmt(AC.getBody());
 
diff --git a/test/SemaCXX/switch-implicit-fallthrough-cxx98.cpp b/test/SemaCXX/switch-implicit-fallthrough-cxx98.cpp
index 14ffcef704..8b24c4a3b1 100644
--- a/test/SemaCXX/switch-implicit-fallthrough-cxx98.cpp
+++ b/test/SemaCXX/switch-implicit-fallthrough-cxx98.cpp
@@ -1,5 +1,8 @@
 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++98 -Wimplicit-fallthrough %s
+// XFAIL: *
 
+// NOTE: This test is marked XFAIL until we come up with a good language design
+// for a worfklow to use this warning outside of C++11.
 
 int fallthrough(int n) {
   switch (n / 10) {