# 22902339 memory corruption caused by undefined behavior in LLVM IR Module

# Miscellaneous cleanup fixes.

# Replace SmallVectorImpl | SmallVector with std::vector.

# 3.9.X upstream.

--- include/llvm/Analysis/BlockFrequencyInfoImpl.h	2015-12-18 12:53:24.000000000 -0900

+++ include/llvm/Analysis/BlockFrequencyInfoImpl.h	2016-07-07 10:08:31.067332185 -0800

@@ -249,7 +249,9 @@

     LoopData *Loop; ///< The loop this block is inside.

     BlockMass Mass; ///< Mass distribution from the entry block.

-    WorkingData(const BlockNode &Node) : Node(Node), Loop(nullptr) {}

+    WorkingData() : Node(), Loop(nullptr), Mass() { }

+    WorkingData(const BlockNode &Node) : Node(Node), Loop(nullptr), Mass() { }

+    ~WorkingData() { }

     bool isLoopHeader() const { return Loop && Loop->isHeader(Node); }

     bool isDoubleLoopHeader() const {

@@ -332,9 +334,10 @@

     DistType Type;

     BlockNode TargetNode;

     uint64_t Amount;

-    Weight() : Type(Local), Amount(0) {}

+    Weight() : Type(Local), TargetNode(), Amount(0ULL) { }

     Weight(DistType Type, BlockNode TargetNode, uint64_t Amount)

-        : Type(Type), TargetNode(TargetNode), Amount(Amount) {}

+    : Type(Type), TargetNode(TargetNode), Amount(Amount) { }

+    ~Weight() { }

   };

   /// \brief Distribution of unscaled probability weight.

@@ -985,7 +988,9 @@

 template <class BT> void BlockFrequencyInfoImpl<BT>::initializeRPOT() {

   const BlockT *Entry = &F->front();

-  RPOT.reserve(F->size());

+  if (F->size())

+    RPOT.reserve(F->size());

+

   std::copy(po_begin(Entry), po_end(Entry), std::back_inserter(RPOT));

   std::reverse(RPOT.begin(), RPOT.end());

@@ -999,7 +1004,9 @@

     Nodes[*I] = Node;

   }

-  Working.reserve(RPOT.size());

+  if (RPOT.size())

+    Working.reserve(RPOT.size());

+

   for (size_t Index = 0; Index < RPOT.size(); ++Index)

     Working.emplace_back(Index);

   Freqs.resize(RPOT.size());

###

--- lib/Analysis/LazyCallGraph.cpp	2015-12-27 20:54:20.000000000 -0500

+++ lib/Analysis/LazyCallGraph.cpp	2016-05-28 13:36:41.670887743 -0400

@@ -234,7 +234,7 @@

   ConnectedSCCs.insert(&CallerC);

   // We build up a DFS stack of the parents chains.

-  SmallVector<std::pair<SCC *, SCC::parent_iterator>, 8> DFSSCCs;

+  std::vector<std::pair<SCC *, SCC::parent_iterator> > DFSSCCs;

   SmallPtrSet<SCC *, 8> VisitedSCCs;

   int ConnectedDepth = -1;

   SCC *C = this;

@@ -265,7 +265,7 @@

     // If we've found a connection anywhere below this point on the stack (and

     // thus up the parent graph from the caller), the current node needs to be

     // added to the connected set now that we've processed all of its parents.

-    if ((int)DFSSCCs.size() == ConnectedDepth) {

+    if (static_cast<int>(DFSSCCs.size()) == ConnectedDepth) {

       --ConnectedDepth; // We're finished with this connection.

       ConnectedSCCs.insert(C);

     } else {

@@ -279,8 +279,9 @@

       break; // We've walked all the parents of the caller transitively.

     // Pop off the prior node and position to unwind the depth first recursion.

-    std::tie(C, I) = DFSSCCs.pop_back_val();

+    std::tie(C, I) = DFSSCCs.back();

     E = C->parent_end();

+    DFSSCCs.pop_back();

   }

   // Now that we have identified all of the SCCs which need to be merged into

###

--- lib/Analysis/CFG.cpp	2015-11-20 15:02:06.000000000 -0800

+++ lib/Analysis/CFG.cpp	2016-05-24 19:44:24.894893025 -0700

@@ -19,6 +19,8 @@

 using namespace llvm;

+#include <vector>

+

 /// FindFunctionBackedges - Analyze the specified function to find all of the

 /// loop backedges in the function and return them.  This is a relatively cheap

 /// (compared to computing dominators and loop info) analysis.

@@ -31,7 +33,7 @@

     return;

   SmallPtrSet<const BasicBlock*, 8> Visited;

-  SmallVector<std::pair<const BasicBlock*, succ_const_iterator>, 8> VisitStack;

+  std::vector<std::pair<const BasicBlock*, succ_const_iterator> > VisitStack;

   SmallPtrSet<const BasicBlock*, 8> InStack;

   Visited.insert(BB);

@@ -60,7 +62,10 @@

       VisitStack.push_back(std::make_pair(BB, succ_begin(BB)));

     } else {

       // Go up one level.

-      InStack.erase(VisitStack.pop_back_val().first);

+      std::pair<const BasicBlock*, succ_const_iterator> &Back =

+        VisitStack.back();

+      InStack.erase(Back.first);

+      VisitStack.pop_back();

     }

   } while (!VisitStack.empty());

 }