Don't suggest to insert [[clang::fallthrough]] before empty cases. Fix for multiple case labels.

llvm-svn: 173458

1 files changed, 10 insertions, 5 deletions

diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index d5fa959bf44..78864ec2852 100644
--- a/clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -846,13 +846,13 @@ static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC,
   int AnnotatedCnt;
 
   for (CFG::reverse_iterator I = Cfg->rbegin(), E = Cfg->rend(); I != E; ++I) {
-    const CFGBlock &B = **I;
-    const Stmt *Label = B.getLabel();
+    const CFGBlock *B = *I;
+    const Stmt *Label = B->getLabel();
 
     if (!Label || !isa<SwitchCase>(Label))
       continue;
 
-    if (!FM.checkFallThroughIntoBlock(B, AnnotatedCnt))
+    if (!FM.checkFallThroughIntoBlock(*B, AnnotatedCnt))
       continue;
 
     S.Diag(Label->getLocStart(),
@@ -864,8 +864,13 @@ static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC,
       if (L.isMacroID())
         continue;
       if (S.getLangOpts().CPlusPlus11) {
-        const Stmt *Term = B.getTerminator();
-        if (!(B.empty() && Term && isa<BreakStmt>(Term))) {
+        const Stmt *Term = B->getTerminator();
+        // Skip empty cases.
+        while (B->empty() && !Term && B->succ_size() == 1) {
+          B = *B->succ_begin();
+          Term = B->getTerminator();
+        }
+        if (!(B->empty() && Term && isa<BreakStmt>(Term))) {
           Preprocessor &PP = S.getPreprocessor();
           TokenValue Tokens[] = {
             tok::l_square, tok::l_square, PP.getIdentifierInfo("clang"),