Analysis: Add a CFG successor to a SwitchStmt if it is both empty and fully covered

Consider the case where a SwitchStmt satisfied isAllEnumCasesCovered()
as well as having no cases at all (i.e. the enum it covers has no
enumerators).

In this case, we should add a successor to repair the CFG.

This fixes PR16212.

llvm-svn: 183237

1 files changed, 8 insertions, 2 deletions

diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp
index e06e6617508..9945dcb36ce 100644
--- a/clang/lib/Analysis/CFG.cpp
+++ b/clang/lib/Analysis/CFG.cpp
@@ -2671,9 +2671,15 @@ CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
   // If we have no "default:" case, the default transition is to the code
   // following the switch body.  Moreover, take into account if all the
   // cases of a switch are covered (e.g., switching on an enum value).
+  //
+  // Note: We add a successor to a switch that is considered covered yet has no
+  //       case statements if the enumeration has no enumerators.
+  bool SwitchAlwaysHasSuccessor = false;
+  SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
+  SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
+                              Terminator->getSwitchCaseList();
   addSuccessor(SwitchTerminatedBlock,
-               switchExclusivelyCovered || Terminator->isAllEnumCasesCovered()
-               ? 0 : DefaultCaseBlock);
+               SwitchAlwaysHasSuccessor ? 0 : DefaultCaseBlock);
 
   // Add the terminator and condition in the switch block.
   SwitchTerminatedBlock->setTerminator(Terminator);