commit f8adeefa9e9882bff402e092024dd457f8574673
author Ted Kremenek <kremenek@apple.com> Mon Apr 04 20:30:58 2011 +0000
committer Ted Kremenek <kremenek@apple.com> Mon Apr 04 20:30:58 2011 +0000
tree 3058605ba5d49ddc2ce05a2db7411faa5690001f
parent 5360c921a91dc43b442f069ba86d7b9df66362fc

-Wuninitialized: don't warn about uninitialized variables in unreachable code.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@128840 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/CFG.cpp

diff --git a/lib/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
index c193112..e91de03 100644
--- a/lib/Analysis/CFG.cpp
+++ b/lib/Analysis/CFG.cpp
@@ -428,8 +428,8 @@
     if (!BuildOpts.PruneTriviallyFalseEdges)
       return false;
     return !S->isTypeDependent() && 
-    !S->isValueDependent() &&
-    S->Evaluate(outResult, *Context);
+           !S->isValueDependent() &&
+           S->Evaluate(outResult, *Context);
   }
 
   /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1

lib/Analysis/UninitializedValues.cpp

diff --git a/lib/Analysis/UninitializedValues.cpp b/lib/Analysis/UninitializedValues.cpp
index 58191ec..f775cc5 100644
--- a/lib/Analysis/UninitializedValues.cpp
+++ b/lib/Analysis/UninitializedValues.cpp
@@ -156,6 +156,8 @@
     return declToIndex.getValueIndex(vd).hasValue();
   }
   
+  bool hasValues(const CFGBlock *block);
+  
   void resetScratch();
   ValueVector &getScratch() { return scratch; }
   
@@ -231,6 +233,11 @@
   return lazyCreate(vals[idx].first);
 }
 
+bool CFGBlockValues::hasValues(const CFGBlock *block) {
+  unsigned idx = block->getBlockID();
+  return vals[idx].second != 0;  
+}
+
 BVPair &CFGBlockValues::getValueVectors(const clang::CFGBlock *block,
                                         bool shouldLazyCreate) {
   unsigned idx = block->getBlockID();
@@ -603,9 +610,12 @@
 
 static bool runOnBlock(const CFGBlock *block, const CFG &cfg,
                        AnalysisContext &ac, CFGBlockValues &vals,
+                       llvm::BitVector &wasAnalyzed,
                        UninitVariablesHandler *handler = 0,
                        bool flagBlockUses = false) {
   
+  wasAnalyzed[block->getBlockID()] = true;
+  
   if (const BinaryOperator *b = getLogicalOperatorInChain(block)) {
     CFGBlock::const_pred_iterator itr = block->pred_begin();
     BVPair vA = vals.getValueVectors(*itr, false);
@@ -663,10 +673,11 @@
   llvm::BitVector previouslyVisited(cfg.getNumBlockIDs());
   
   worklist.enqueueSuccessors(&cfg.getEntry());
+  llvm::BitVector wasAnalyzed(cfg.getNumBlockIDs(), false);
 
   while (const CFGBlock *block = worklist.dequeue()) {
     // Did the block change?
-    bool changed = runOnBlock(block, cfg, ac, vals);    
+    bool changed = runOnBlock(block, cfg, ac, vals, wasAnalyzed);    
     if (changed || !previouslyVisited[block->getBlockID()])
       worklist.enqueueSuccessors(block);    
     previouslyVisited[block->getBlockID()] = true;
@@ -674,7 +685,9 @@
   
   // Run through the blocks one more time, and report uninitialized variabes.
   for (CFG::const_iterator BI = cfg.begin(), BE = cfg.end(); BI != BE; ++BI) {
-    runOnBlock(*BI, cfg, ac, vals, &handler, /* flagBlockUses */ true);
+    if (wasAnalyzed[(*BI)->getBlockID()])
+      runOnBlock(*BI, cfg, ac, vals, wasAnalyzed, &handler,
+                 /* flagBlockUses */ true);
   }
 }
 

test/SemaCXX/uninit-variables.cpp

diff --git a/test/SemaCXX/uninit-variables.cpp b/test/SemaCXX/uninit-variables.cpp
index 77cbcf7..6fa59fe 100644
--- a/test/SemaCXX/uninit-variables.cpp
+++ b/test/SemaCXX/uninit-variables.cpp
@@ -70,3 +70,11 @@
   virtual void bar(void) const;
 };
 void Rdar9188004C::bar(void) const {}
+
+// Don't warn about uninitialized variables in unreachable code.
+void PR9625() {
+  if (false) {
+    int x;
+    (void)static_cast<float>(x); // no-warning
+  }
+}