Merge branch 'master' of ssh://bitbucket.org/czan/honours

1 files changed, 1463 insertions, 0 deletions

diff --git a/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
new file mode 100644
index 0000000..8bce88a
--- /dev/null
+++ b/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
@@ -0,0 +1,1463 @@
+//=== MallocChecker.cpp - A malloc/free checker -------------------*- C++ -*--//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines malloc/free checker, which checks for potential memory
+// leaks, double free, and use-after-free problems.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ClangSACheckers.h"
+#include "InterCheckerAPI.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/CheckerManager.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/ObjCMessage.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
+#include "clang/Basic/SourceManager.h"
+#include "llvm/ADT/ImmutableMap.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/STLExtras.h"
+#include <climits>
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+
+class RefState {
+  enum Kind { AllocateUnchecked, AllocateFailed, Released, Escaped,
+              Relinquished } K;
+  const Stmt *S;
+
+public:
+  RefState(Kind k, const Stmt *s) : K(k), S(s) {}
+
+  bool isAllocated() const { return K == AllocateUnchecked; }
+  bool isReleased() const { return K == Released; }
+
+  const Stmt *getStmt() const { return S; }
+
+  bool operator==(const RefState &X) const {
+    return K == X.K && S == X.S;
+  }
+
+  static RefState getAllocateUnchecked(const Stmt *s) { 
+    return RefState(AllocateUnchecked, s); 
+  }
+  static RefState getAllocateFailed() {
+    return RefState(AllocateFailed, 0);
+  }
+  static RefState getReleased(const Stmt *s) { return RefState(Released, s); }
+  static RefState getEscaped(const Stmt *s) { return RefState(Escaped, s); }
+  static RefState getRelinquished(const Stmt *s) {
+    return RefState(Relinquished, s);
+  }
+
+  void Profile(llvm::FoldingSetNodeID &ID) const {
+    ID.AddInteger(K);
+    ID.AddPointer(S);
+  }
+};
+
+struct ReallocPair {
+  SymbolRef ReallocatedSym;
+  bool IsFreeOnFailure;
+  ReallocPair(SymbolRef S, bool F) : ReallocatedSym(S), IsFreeOnFailure(F) {}
+  void Profile(llvm::FoldingSetNodeID &ID) const {
+    ID.AddInteger(IsFreeOnFailure);
+    ID.AddPointer(ReallocatedSym);
+  }
+  bool operator==(const ReallocPair &X) const {
+    return ReallocatedSym == X.ReallocatedSym &&
+           IsFreeOnFailure == X.IsFreeOnFailure;
+  }
+};
+
+typedef std::pair<const Stmt*, const MemRegion*> LeakInfo;
+
+class MallocChecker : public Checker<check::DeadSymbols,
+                                     check::EndPath,
+                                     check::PreStmt<ReturnStmt>,
+                                     check::PreStmt<CallExpr>,
+                                     check::PostStmt<CallExpr>,
+                                     check::PostStmt<BlockExpr>,
+                                     check::Location,
+                                     check::Bind,
+                                     eval::Assume,
+                                     check::RegionChanges>
+{
+  mutable OwningPtr<BugType> BT_DoubleFree;
+  mutable OwningPtr<BugType> BT_Leak;
+  mutable OwningPtr<BugType> BT_UseFree;
+  mutable OwningPtr<BugType> BT_BadFree;
+  mutable IdentifierInfo *II_malloc, *II_free, *II_realloc, *II_calloc,
+                         *II_valloc, *II_reallocf, *II_strndup, *II_strdup;
+
+public:
+  MallocChecker() : II_malloc(0), II_free(0), II_realloc(0), II_calloc(0),
+                    II_valloc(0), II_reallocf(0), II_strndup(0), II_strdup(0) {}
+
+  /// In pessimistic mode, the checker assumes that it does not know which
+  /// functions might free the memory.
+  struct ChecksFilter {
+    DefaultBool CMallocPessimistic;
+    DefaultBool CMallocOptimistic;
+  };
+
+  ChecksFilter Filter;
+
+  void checkPreStmt(const CallExpr *S, CheckerContext &C) const;
+  void checkPostStmt(const CallExpr *CE, CheckerContext &C) const;
+  void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const;
+  void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
+  void checkEndPath(CheckerContext &C) const;
+  void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const;
+  ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond,
+                            bool Assumption) const;
+  void checkLocation(SVal l, bool isLoad, const Stmt *S,
+                     CheckerContext &C) const;
+  void checkBind(SVal location, SVal val, const Stmt*S,
+                 CheckerContext &C) const;
+  ProgramStateRef
+  checkRegionChanges(ProgramStateRef state,
+                     const StoreManager::InvalidatedSymbols *invalidated,
+                     ArrayRef<const MemRegion *> ExplicitRegions,
+                     ArrayRef<const MemRegion *> Regions,
+                     const CallOrObjCMessage *Call) const;
+  bool wantsRegionChangeUpdate(ProgramStateRef state) const {
+    return true;
+  }
+
+private:
+  void initIdentifierInfo(ASTContext &C) const;
+
+  /// Check if this is one of the functions which can allocate/reallocate memory 
+  /// pointed to by one of its arguments.
+  bool isMemFunction(const FunctionDecl *FD, ASTContext &C) const;
+
+  static ProgramStateRef MallocMemReturnsAttr(CheckerContext &C,
+                                              const CallExpr *CE,
+                                              const OwnershipAttr* Att);
+  static ProgramStateRef MallocMemAux(CheckerContext &C, const CallExpr *CE,
+                                     const Expr *SizeEx, SVal Init,
+                                     ProgramStateRef state) {
+    return MallocMemAux(C, CE,
+                        state->getSVal(SizeEx, C.getLocationContext()),
+                        Init, state);
+  }
+
+  static ProgramStateRef MallocMemAux(CheckerContext &C, const CallExpr *CE,
+                                     SVal SizeEx, SVal Init,
+                                     ProgramStateRef state);
+
+  /// Update the RefState to reflect the new memory allocation.
+  static ProgramStateRef MallocUpdateRefState(CheckerContext &C,
+                                              const CallExpr *CE,
+                                              ProgramStateRef state);
+
+  ProgramStateRef FreeMemAttr(CheckerContext &C, const CallExpr *CE,
+                              const OwnershipAttr* Att) const;
+  ProgramStateRef FreeMemAux(CheckerContext &C, const CallExpr *CE,
+                                 ProgramStateRef state, unsigned Num,
+                                 bool Hold) const;
+
+  ProgramStateRef ReallocMem(CheckerContext &C, const CallExpr *CE,
+                             bool FreesMemOnFailure) const;
+  static ProgramStateRef CallocMem(CheckerContext &C, const CallExpr *CE);
+  
+  bool checkEscape(SymbolRef Sym, const Stmt *S, CheckerContext &C) const;
+  bool checkUseAfterFree(SymbolRef Sym, CheckerContext &C,
+                         const Stmt *S = 0) const;
+
+  /// Check if the function is not known to us. So, for example, we could
+  /// conservatively assume it can free/reallocate it's pointer arguments.
+  bool doesNotFreeMemory(const CallOrObjCMessage *Call,
+                         ProgramStateRef State) const;
+
+  static bool SummarizeValue(raw_ostream &os, SVal V);
+  static bool SummarizeRegion(raw_ostream &os, const MemRegion *MR);
+  void ReportBadFree(CheckerContext &C, SVal ArgVal, SourceRange range) const;
+
+  /// Find the location of the allocation for Sym on the path leading to the
+  /// exploded node N.
+  LeakInfo getAllocationSite(const ExplodedNode *N, SymbolRef Sym,
+                             CheckerContext &C) const;
+
+  void reportLeak(SymbolRef Sym, ExplodedNode *N, CheckerContext &C) const;
+
+  /// The bug visitor which allows us to print extra diagnostics along the
+  /// BugReport path. For example, showing the allocation site of the leaked
+  /// region.
+  class MallocBugVisitor : public BugReporterVisitorImpl<MallocBugVisitor> {
+  protected:
+    enum NotificationMode {
+      Normal,
+      ReallocationFailed
+    };
+
+    // The allocated region symbol tracked by the main analysis.
+    SymbolRef Sym;
+
+     // The mode we are in, i.e. what kind of diagnostics will be emitted.
+     NotificationMode Mode;
+
+     // A symbol from when the primary region should have been reallocated.
+     SymbolRef FailedReallocSymbol;
+
+   public:
+     MallocBugVisitor(SymbolRef S)
+       : Sym(S), Mode(Normal), FailedReallocSymbol(0) {}
+
+    virtual ~MallocBugVisitor() {}
+
+    void Profile(llvm::FoldingSetNodeID &ID) const {
+      static int X = 0;
+      ID.AddPointer(&X);
+      ID.AddPointer(Sym);
+    }
+
+    inline bool isAllocated(const RefState *S, const RefState *SPrev,
+                            const Stmt *Stmt) {
+      // Did not track -> allocated. Other state (released) -> allocated.
+      return (Stmt && isa<CallExpr>(Stmt) &&
+              (S && S->isAllocated()) && (!SPrev || !SPrev->isAllocated()));
+    }
+
+    inline bool isReleased(const RefState *S, const RefState *SPrev,
+                           const Stmt *Stmt) {
+      // Did not track -> released. Other state (allocated) -> released.
+      return (Stmt && isa<CallExpr>(Stmt) &&
+              (S && S->isReleased()) && (!SPrev || !SPrev->isReleased()));
+    }
+
+    inline bool isReallocFailedCheck(const RefState *S, const RefState *SPrev,
+                                     const Stmt *Stmt) {
+      // If the expression is not a call, and the state change is
+      // released -> allocated, it must be the realloc return value
+      // check. If we have to handle more cases here, it might be cleaner just
+      // to track this extra bit in the state itself.
+      return ((!Stmt || !isa<CallExpr>(Stmt)) &&
+              (S && S->isAllocated()) && (SPrev && !SPrev->isAllocated()));
+    }
+
+    PathDiagnosticPiece *VisitNode(const ExplodedNode *N,
+                                   const ExplodedNode *PrevN,
+                                   BugReporterContext &BRC,
+                                   BugReport &BR);
+  private:
+    class StackHintGeneratorForReallocationFailed
+        : public StackHintGeneratorForSymbol {
+    public:
+      StackHintGeneratorForReallocationFailed(SymbolRef S, StringRef M)
+        : StackHintGeneratorForSymbol(S, M) {}
+
+      virtual std::string getMessageForArg(const Expr *ArgE, unsigned ArgIndex) {
+        SmallString<200> buf;
+        llvm::raw_svector_ostream os(buf);
+
+        os << "Reallocation of ";
+        // Printed parameters start at 1, not 0.
+        printOrdinal(++ArgIndex, os);
+        os << " parameter failed";
+
+        return os.str();
+      }
+
+      virtual std::string getMessageForReturn(const CallExpr *CallExpr) {
+        return "Reallocation of returned value failed";
+      }
+    };
+  };
+};
+} // end anonymous namespace
+
+typedef llvm::ImmutableMap<SymbolRef, RefState> RegionStateTy;
+typedef llvm::ImmutableMap<SymbolRef, ReallocPair > ReallocMap;
+class RegionState {};
+class ReallocPairs {};
+namespace clang {
+namespace ento {
+  template <>
+  struct ProgramStateTrait<RegionState> 
+    : public ProgramStatePartialTrait<RegionStateTy> {
+    static void *GDMIndex() { static int x; return &x; }
+  };
+
+  template <>
+  struct ProgramStateTrait<ReallocPairs>
+    : public ProgramStatePartialTrait<ReallocMap> {
+    static void *GDMIndex() { static int x; return &x; }
+  };
+}
+}
+
+namespace {
+class StopTrackingCallback : public SymbolVisitor {
+  ProgramStateRef state;
+public:
+  StopTrackingCallback(ProgramStateRef st) : state(st) {}
+  ProgramStateRef getState() const { return state; }
+
+  bool VisitSymbol(SymbolRef sym) {
+    state = state->remove<RegionState>(sym);
+    return true;
+  }
+};
+} // end anonymous namespace
+
+void MallocChecker::initIdentifierInfo(ASTContext &Ctx) const {
+  if (!II_malloc)
+    II_malloc = &Ctx.Idents.get("malloc");
+  if (!II_free)
+    II_free = &Ctx.Idents.get("free");
+  if (!II_realloc)
+    II_realloc = &Ctx.Idents.get("realloc");
+  if (!II_reallocf)
+    II_reallocf = &Ctx.Idents.get("reallocf");
+  if (!II_calloc)
+    II_calloc = &Ctx.Idents.get("calloc");
+  if (!II_valloc)
+    II_valloc = &Ctx.Idents.get("valloc");
+  if (!II_strdup)
+    II_strdup = &Ctx.Idents.get("strdup");
+  if (!II_strndup)
+    II_strndup = &Ctx.Idents.get("strndup");
+}
+
+bool MallocChecker::isMemFunction(const FunctionDecl *FD, ASTContext &C) const {
+  if (!FD)
+    return false;
+  IdentifierInfo *FunI = FD->getIdentifier();
+  if (!FunI)
+    return false;
+
+  initIdentifierInfo(C);
+
+  if (FunI == II_malloc || FunI == II_free || FunI == II_realloc ||
+      FunI == II_reallocf || FunI == II_calloc || FunI == II_valloc ||
+      FunI == II_strdup || FunI == II_strndup)
+    return true;
+
+  if (Filter.CMallocOptimistic && FD->hasAttrs() &&
+      FD->specific_attr_begin<OwnershipAttr>() !=
+          FD->specific_attr_end<OwnershipAttr>())
+    return true;
+
+
+  return false;
+}
+
+void MallocChecker::checkPostStmt(const CallExpr *CE, CheckerContext &C) const {
+  const FunctionDecl *FD = C.getCalleeDecl(CE);
+  if (!FD)
+    return;
+
+  initIdentifierInfo(C.getASTContext());
+  IdentifierInfo *FunI = FD->getIdentifier();
+  if (!FunI)
+    return;
+
+  ProgramStateRef State = C.getState();
+  if (FunI == II_malloc || FunI == II_valloc) {
+    if (CE->getNumArgs() < 1)
+      return;
+    State = MallocMemAux(C, CE, CE->getArg(0), UndefinedVal(), State);
+  } else if (FunI == II_realloc) {
+    State = ReallocMem(C, CE, false);
+  } else if (FunI == II_reallocf) {
+    State = ReallocMem(C, CE, true);
+  } else if (FunI == II_calloc) {
+    State = CallocMem(C, CE);
+  } else if (FunI == II_free) {
+    State = FreeMemAux(C, CE, C.getState(), 0, false);
+  } else if (FunI == II_strdup) {
+    State = MallocUpdateRefState(C, CE, State);
+  } else if (FunI == II_strndup) {
+    State = MallocUpdateRefState(C, CE, State);
+  } else if (Filter.CMallocOptimistic) {
+    // Check all the attributes, if there are any.
+    // There can be multiple of these attributes.
+    if (FD->hasAttrs())
+      for (specific_attr_iterator<OwnershipAttr>
+          i = FD->specific_attr_begin<OwnershipAttr>(),
+          e = FD->specific_attr_end<OwnershipAttr>();
+          i != e; ++i) {
+        switch ((*i)->getOwnKind()) {
+        case OwnershipAttr::Returns:
+          State = MallocMemReturnsAttr(C, CE, *i);
+          break;
+        case OwnershipAttr::Takes:
+        case OwnershipAttr::Holds:
+          State = FreeMemAttr(C, CE, *i);
+          break;
+        }
+      }
+  }
+  C.addTransition(State);
+}
+
+ProgramStateRef MallocChecker::MallocMemReturnsAttr(CheckerContext &C,
+                                                    const CallExpr *CE,
+                                                    const OwnershipAttr* Att) {
+  if (Att->getModule() != "malloc")
+    return 0;
+
+  OwnershipAttr::args_iterator I = Att->args_begin(), E = Att->args_end();
+  if (I != E) {
+    return MallocMemAux(C, CE, CE->getArg(*I), UndefinedVal(), C.getState());
+  }
+  return MallocMemAux(C, CE, UnknownVal(), UndefinedVal(), C.getState());
+}
+
+ProgramStateRef MallocChecker::MallocMemAux(CheckerContext &C,
+                                           const CallExpr *CE,
+                                           SVal Size, SVal Init,
+                                           ProgramStateRef state) {
+  // Get the return value.
+  SVal retVal = state->getSVal(CE, C.getLocationContext());
+
+  // We expect the malloc functions to return a pointer.
+  if (!isa<Loc>(retVal))
+    return 0;
+
+  // Fill the region with the initialization value.
+  state = state->bindDefault(retVal, Init);
+
+  // Set the region's extent equal to the Size parameter.
+  const SymbolicRegion *R =
+      dyn_cast_or_null<SymbolicRegion>(retVal.getAsRegion());
+  if (!R)
+    return 0;
+  if (isa<DefinedOrUnknownSVal>(Size)) {
+    SValBuilder &svalBuilder = C.getSValBuilder();
+    DefinedOrUnknownSVal Extent = R->getExtent(svalBuilder);
+    DefinedOrUnknownSVal DefinedSize = cast<DefinedOrUnknownSVal>(Size);
+    DefinedOrUnknownSVal extentMatchesSize =
+        svalBuilder.evalEQ(state, Extent, DefinedSize);
+
+    state = state->assume(extentMatchesSize, true);
+    assert(state);
+  }
+  
+  return MallocUpdateRefState(C, CE, state);
+}
+
+ProgramStateRef MallocChecker::MallocUpdateRefState(CheckerContext &C,
+                                                    const CallExpr *CE,
+                                                    ProgramStateRef state) {
+  // Get the return value.
+  SVal retVal = state->getSVal(CE, C.getLocationContext());
+
+  // We expect the malloc functions to return a pointer.
+  if (!isa<Loc>(retVal))
+    return 0;
+
+  SymbolRef Sym = retVal.getAsLocSymbol();
+  assert(Sym);
+
+  // Set the symbol's state to Allocated.
+  return state->set<RegionState>(Sym, RefState::getAllocateUnchecked(CE));
+
+}
+
+ProgramStateRef MallocChecker::FreeMemAttr(CheckerContext &C,
+                                           const CallExpr *CE,
+                                           const OwnershipAttr* Att) const {
+  if (Att->getModule() != "malloc")
+    return 0;
+
+  ProgramStateRef State = C.getState();
+
+  for (OwnershipAttr::args_iterator I = Att->args_begin(), E = Att->args_end();
+       I != E; ++I) {
+    ProgramStateRef StateI = FreeMemAux(C, CE, State, *I,
+                               Att->getOwnKind() == OwnershipAttr::Holds);
+    if (StateI)
+      State = StateI;
+  }
+  return State;
+}
+
+ProgramStateRef MallocChecker::FreeMemAux(CheckerContext &C,
+                                          const CallExpr *CE,
+                                          ProgramStateRef state,
+                                          unsigned Num,
+                                          bool Hold) const {
+  if (CE->getNumArgs() < (Num + 1))
+    return 0;
+
+  const Expr *ArgExpr = CE->getArg(Num);
+  SVal ArgVal = state->getSVal(ArgExpr, C.getLocationContext());
+  if (!isa<DefinedOrUnknownSVal>(ArgVal))
+    return 0;
+  DefinedOrUnknownSVal location = cast<DefinedOrUnknownSVal>(ArgVal);
+
+  // Check for null dereferences.
+  if (!isa<Loc>(location))
+    return 0;
+
+  // The explicit NULL case, no operation is performed.
+  ProgramStateRef notNullState, nullState;
+  llvm::tie(notNullState, nullState) = state->assume(location);
+  if (nullState && !notNullState)
+    return 0;
+
+  // Unknown values could easily be okay
+  // Undefined values are handled elsewhere
+  if (ArgVal.isUnknownOrUndef())
+    return 0;
+
+  const MemRegion *R = ArgVal.getAsRegion();
+  
+  // Nonlocs can't be freed, of course.
+  // Non-region locations (labels and fixed addresses) also shouldn't be freed.
+  if (!R) {
+    ReportBadFree(C, ArgVal, ArgExpr->getSourceRange());
+    return 0;
+  }
+  
+  R = R->StripCasts();
+  
+  // Blocks might show up as heap data, but should not be free()d
+  if (isa<BlockDataRegion>(R)) {
+    ReportBadFree(C, ArgVal, ArgExpr->getSourceRange());
+    return 0;
+  }
+  
+  const MemSpaceRegion *MS = R->getMemorySpace();
+  
+  // Parameters, locals, statics, and globals shouldn't be freed.
+  if (!(isa<UnknownSpaceRegion>(MS) || isa<HeapSpaceRegion>(MS))) {
+    // FIXME: at the time this code was written, malloc() regions were
+    // represented by conjured symbols, which are all in UnknownSpaceRegion.
+    // This means that there isn't actually anything from HeapSpaceRegion
+    // that should be freed, even though we allow it here.
+    // Of course, free() can work on memory allocated outside the current
+    // function, so UnknownSpaceRegion is always a possibility.
+    // False negatives are better than false positives.
+    
+    ReportBadFree(C, ArgVal, ArgExpr->getSourceRange());
+    return 0;
+  }
+  
+  const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R);
+  // Various cases could lead to non-symbol values here.
+  // For now, ignore them.
+  if (!SR)
+    return 0;
+
+  SymbolRef Sym = SR->getSymbol();
+  const RefState *RS = state->get<RegionState>(Sym);
+
+  // If the symbol has not been tracked, return. This is possible when free() is
+  // called on a pointer that does not get its pointee directly from malloc(). 
+  // Full support of this requires inter-procedural analysis.
+  if (!RS)
+    return 0;
+
+  // Check double free.
+  if (RS->isReleased()) {
+    if (ExplodedNode *N = C.generateSink()) {
+      if (!BT_DoubleFree)
+        BT_DoubleFree.reset(
+          new BugType("Double free", "Memory Error"));
+      BugReport *R = new BugReport(*BT_DoubleFree, 
+                        "Attempt to free released memory", N);
+      R->addRange(ArgExpr->getSourceRange());
+      R->markInteresting(Sym);
+      R->addVisitor(new MallocBugVisitor(Sym));
+      C.EmitReport(R);
+    }
+    return 0;
+  }
+
+  // Normal free.
+  if (Hold)
+    return state->set<RegionState>(Sym, RefState::getRelinquished(CE));
+  return state->set<RegionState>(Sym, RefState::getReleased(CE));
+}
+
+bool MallocChecker::SummarizeValue(raw_ostream &os, SVal V) {
+  if (nonloc::ConcreteInt *IntVal = dyn_cast<nonloc::ConcreteInt>(&V))
+    os << "an integer (" << IntVal->getValue() << ")";
+  else if (loc::ConcreteInt *ConstAddr = dyn_cast<loc::ConcreteInt>(&V))
+    os << "a constant address (" << ConstAddr->getValue() << ")";
+  else if (loc::GotoLabel *Label = dyn_cast<loc::GotoLabel>(&V))
+    os << "the address of the label '" << Label->getLabel()->getName() << "'";
+  else
+    return false;
+  
+  return true;
+}
+
+bool MallocChecker::SummarizeRegion(raw_ostream &os,
+                                    const MemRegion *MR) {
+  switch (MR->getKind()) {
+  case MemRegion::FunctionTextRegionKind: {
+    const FunctionDecl *FD = cast<FunctionTextRegion>(MR)->getDecl();
+    if (FD)
+      os << "the address of the function '" << *FD << '\'';
+    else
+      os << "the address of a function";
+    return true;
+  }
+  case MemRegion::BlockTextRegionKind:
+    os << "block text";
+    return true;
+  case MemRegion::BlockDataRegionKind:
+    // FIXME: where the block came from?
+    os << "a block";
+    return true;
+  default: {
+    const MemSpaceRegion *MS = MR->getMemorySpace();
+    
+    if (isa<StackLocalsSpaceRegion>(MS)) {
+      const VarRegion *VR = dyn_cast<VarRegion>(MR);
+      const VarDecl *VD;
+      if (VR)
+        VD = VR->getDecl();
+      else
+        VD = NULL;
+      
+      if (VD)
+        os << "the address of the local variable '" << VD->getName() << "'";
+      else
+        os << "the address of a local stack variable";
+      return true;
+    }
+
+    if (isa<StackArgumentsSpaceRegion>(MS)) {
+      const VarRegion *VR = dyn_cast<VarRegion>(MR);
+      const VarDecl *VD;
+      if (VR)
+        VD = VR->getDecl();
+      else
+        VD = NULL;
+      
+      if (VD)
+        os << "the address of the parameter '" << VD->getName() << "'";
+      else
+        os << "the address of a parameter";
+      return true;
+    }
+
+    if (isa<GlobalsSpaceRegion>(MS)) {
+      const VarRegion *VR = dyn_cast<VarRegion>(MR);
+      const VarDecl *VD;
+      if (VR)
+        VD = VR->getDecl();
+      else
+        VD = NULL;
+      
+      if (VD) {
+        if (VD->isStaticLocal())
+          os << "the address of the static variable '" << VD->getName() << "'";
+        else
+          os << "the address of the global variable '" << VD->getName() << "'";
+      } else
+        os << "the address of a global variable";
+      return true;
+    }
+
+    return false;
+  }
+  }
+}
+
+void MallocChecker::ReportBadFree(CheckerContext &C, SVal ArgVal,
+                                  SourceRange range) const {
+  if (ExplodedNode *N = C.generateSink()) {
+    if (!BT_BadFree)
+      BT_BadFree.reset(new BugType("Bad free", "Memory Error"));
+    
+    SmallString<100> buf;
+    llvm::raw_svector_ostream os(buf);
+    
+    const MemRegion *MR = ArgVal.getAsRegion();
+    if (MR) {
+      while (const ElementRegion *ER = dyn_cast<ElementRegion>(MR))
+        MR = ER->getSuperRegion();
+      
+      // Special case for alloca()
+      if (isa<AllocaRegion>(MR))
+        os << "Argument to free() was allocated by alloca(), not malloc()";
+      else {
+        os << "Argument to free() is ";
+        if (SummarizeRegion(os, MR))
+          os << ", which is not memory allocated by malloc()";
+        else
+          os << "not memory allocated by malloc()";
+      }
+    } else {
+      os << "Argument to free() is ";
+      if (SummarizeValue(os, ArgVal))
+        os << ", which is not memory allocated by malloc()";
+      else
+        os << "not memory allocated by malloc()";
+    }
+    
+    BugReport *R = new BugReport(*BT_BadFree, os.str(), N);
+    R->markInteresting(MR);
+    R->addRange(range);
+    C.EmitReport(R);
+  }
+}
+
+ProgramStateRef MallocChecker::ReallocMem(CheckerContext &C,
+                                          const CallExpr *CE,
+                                          bool FreesOnFail) const {
+  if (CE->getNumArgs() < 2)
+    return 0;
+
+  ProgramStateRef state = C.getState();
+  const Expr *arg0Expr = CE->getArg(0);
+  const LocationContext *LCtx = C.getLocationContext();
+  SVal Arg0Val = state->getSVal(arg0Expr, LCtx);
+  if (!isa<DefinedOrUnknownSVal>(Arg0Val))
+    return 0;
+  DefinedOrUnknownSVal arg0Val = cast<DefinedOrUnknownSVal>(Arg0Val);
+
+  SValBuilder &svalBuilder = C.getSValBuilder();
+
+  DefinedOrUnknownSVal PtrEQ =
+    svalBuilder.evalEQ(state, arg0Val, svalBuilder.makeNull());
+
+  // Get the size argument. If there is no size arg then give up.
+  const Expr *Arg1 = CE->getArg(1);
+  if (!Arg1)
+    return 0;
+
+  // Get the value of the size argument.
+  SVal Arg1ValG = state->getSVal(Arg1, LCtx);
+  if (!isa<DefinedOrUnknownSVal>(Arg1ValG))
+    return 0;
+  DefinedOrUnknownSVal Arg1Val = cast<DefinedOrUnknownSVal>(Arg1ValG);
+
+  // Compare the size argument to 0.
+  DefinedOrUnknownSVal SizeZero =
+    svalBuilder.evalEQ(state, Arg1Val,
+                       svalBuilder.makeIntValWithPtrWidth(0, false));
+
+  ProgramStateRef StatePtrIsNull, StatePtrNotNull;
+  llvm::tie(StatePtrIsNull, StatePtrNotNull) = state->assume(PtrEQ);
+  ProgramStateRef StateSizeIsZero, StateSizeNotZero;
+  llvm::tie(StateSizeIsZero, StateSizeNotZero) = state->assume(SizeZero);
+  // We only assume exceptional states if they are definitely true; if the
+  // state is under-constrained, assume regular realloc behavior.
+  bool PrtIsNull = StatePtrIsNull && !StatePtrNotNull;
+  bool SizeIsZero = StateSizeIsZero && !StateSizeNotZero;
+
+  // If the ptr is NULL and the size is not 0, the call is equivalent to 
+  // malloc(size).
+  if ( PrtIsNull && !SizeIsZero) {
+    ProgramStateRef stateMalloc = MallocMemAux(C, CE, CE->getArg(1),
+                                               UndefinedVal(), StatePtrIsNull);
+    return stateMalloc;
+  }
+
+  if (PrtIsNull && SizeIsZero)
+    return 0;
+
+  // Get the from and to pointer symbols as in toPtr = realloc(fromPtr, size).
+  assert(!PrtIsNull);
+  SymbolRef FromPtr = arg0Val.getAsSymbol();
+  SVal RetVal = state->getSVal(CE, LCtx);
+  SymbolRef ToPtr = RetVal.getAsSymbol();
+  if (!FromPtr || !ToPtr)
+    return 0;
+
+  // If the size is 0, free the memory.
+  if (SizeIsZero)
+    if (ProgramStateRef stateFree = FreeMemAux(C, CE, StateSizeIsZero,0,false)){
+      // The semantics of the return value are:
+      // If size was equal to 0, either NULL or a pointer suitable to be passed
+      // to free() is returned.
+      stateFree = stateFree->set<ReallocPairs>(ToPtr,
+                                            ReallocPair(FromPtr, FreesOnFail));
+      C.getSymbolManager().addSymbolDependency(ToPtr, FromPtr);
+      return stateFree;
+    }
+
+  // Default behavior.
+  if (ProgramStateRef stateFree = FreeMemAux(C, CE, state, 0, false)) {
+    // FIXME: We should copy the content of the original buffer.
+    ProgramStateRef stateRealloc = MallocMemAux(C, CE, CE->getArg(1),
+                                                UnknownVal(), stateFree);
+    if (!stateRealloc)
+      return 0;
+    stateRealloc = stateRealloc->set<ReallocPairs>(ToPtr,
+                                            ReallocPair(FromPtr, FreesOnFail));
+    C.getSymbolManager().addSymbolDependency(ToPtr, FromPtr);
+    return stateRealloc;
+  }
+  return 0;
+}
+
+ProgramStateRef MallocChecker::CallocMem(CheckerContext &C, const CallExpr *CE){
+  if (CE->getNumArgs() < 2)
+    return 0;
+
+  ProgramStateRef state = C.getState();
+  SValBuilder &svalBuilder = C.getSValBuilder();
+  const LocationContext *LCtx = C.getLocationContext();
+  SVal count = state->getSVal(CE->getArg(0), LCtx);
+  SVal elementSize = state->getSVal(CE->getArg(1), LCtx);
+  SVal TotalSize = svalBuilder.evalBinOp(state, BO_Mul, count, elementSize,
+                                        svalBuilder.getContext().getSizeType());  
+  SVal zeroVal = svalBuilder.makeZeroVal(svalBuilder.getContext().CharTy);
+
+  return MallocMemAux(C, CE, TotalSize, zeroVal, state);
+}
+
+LeakInfo
+MallocChecker::getAllocationSite(const ExplodedNode *N, SymbolRef Sym,
+                                 CheckerContext &C) const {
+  const LocationContext *LeakContext = N->getLocationContext();
+  // Walk the ExplodedGraph backwards and find the first node that referred to
+  // the tracked symbol.
+  const ExplodedNode *AllocNode = N;
+  const MemRegion *ReferenceRegion = 0;
+
+  while (N) {
+    ProgramStateRef State = N->getState();
+    if (!State->get<RegionState>(Sym))
+      break;
+
+    // Find the most recent expression bound to the symbol in the current
+    // context.
+    if (!ReferenceRegion) {
+      if (const MemRegion *MR = C.getLocationRegionIfPostStore(N)) {
+        SVal Val = State->getSVal(MR);
+        if (Val.getAsLocSymbol() == Sym)
+          ReferenceRegion = MR;
+      }
+    }
+
+    // Allocation node, is the last node in the current context in which the
+    // symbol was tracked.
+    if (N->getLocationContext() == LeakContext)
+      AllocNode = N;
+    N = N->pred_empty() ? NULL : *(N->pred_begin());
+  }
+
+  ProgramPoint P = AllocNode->getLocation();
+  const Stmt *AllocationStmt = 0;
+  if (isa<StmtPoint>(P))
+    AllocationStmt = cast<StmtPoint>(P).getStmt();
+
+  return LeakInfo(AllocationStmt, ReferenceRegion);
+}
+
+void MallocChecker::reportLeak(SymbolRef Sym, ExplodedNode *N,
+                               CheckerContext &C) const {
+  assert(N);
+  if (!BT_Leak) {
+    BT_Leak.reset(new BugType("Memory leak", "Memory Error"));
+    // Leaks should not be reported if they are post-dominated by a sink:
+    // (1) Sinks are higher importance bugs.
+    // (2) NoReturnFunctionChecker uses sink nodes to represent paths ending
+    //     with __noreturn functions such as assert() or exit(). We choose not
+    //     to report leaks on such paths.
+    BT_Leak->setSuppressOnSink(true);
+  }
+
+  // Most bug reports are cached at the location where they occurred.
+  // With leaks, we want to unique them by the location where they were
+  // allocated, and only report a single path.
+  PathDiagnosticLocation LocUsedForUniqueing;
+  const Stmt *AllocStmt = 0;
+  const MemRegion *Region = 0;
+  llvm::tie(AllocStmt, Region) = getAllocationSite(N, Sym, C);
+  if (AllocStmt)
+    LocUsedForUniqueing = PathDiagnosticLocation::createBegin(AllocStmt,
+                            C.getSourceManager(), N->getLocationContext());
+
+  SmallString<200> buf;
+  llvm::raw_svector_ostream os(buf);
+  os << "Memory is never released; potential leak";
+  if (Region) {
+    os << " of memory pointed to by '";
+    Region->dumpPretty(os);
+    os <<'\'';
+  }
+
+  BugReport *R = new BugReport(*BT_Leak, os.str(), N, LocUsedForUniqueing);
+  R->markInteresting(Sym);
+  R->addVisitor(new MallocBugVisitor(Sym));
+  C.EmitReport(R);
+}
+
+void MallocChecker::checkDeadSymbols(SymbolReaper &SymReaper,
+                                     CheckerContext &C) const
+{
+  if (!SymReaper.hasDeadSymbols())
+    return;
+
+  ProgramStateRef state = C.getState();
+  RegionStateTy RS = state->get<RegionState>();
+  RegionStateTy::Factory &F = state->get_context<RegionState>();
+
+  bool generateReport = false;
+  llvm::SmallVector<SymbolRef, 2> Errors;
+  for (RegionStateTy::iterator I = RS.begin(), E = RS.end(); I != E; ++I) {
+    if (SymReaper.isDead(I->first)) {
+      if (I->second.isAllocated()) {
+        generateReport = true;
+        Errors.push_back(I->first);
+      }
+      // Remove the dead symbol from the map.
+      RS = F.remove(RS, I->first);
+
+    }
+  }
+  
+  // Cleanup the Realloc Pairs Map.
+  ReallocMap RP = state->get<ReallocPairs>();
+  for (ReallocMap::iterator I = RP.begin(), E = RP.end(); I != E; ++I) {
+    if (SymReaper.isDead(I->first) ||
+        SymReaper.isDead(I->second.ReallocatedSym)) {
+      state = state->remove<ReallocPairs>(I->first);
+    }
+  }
+
+  // Generate leak node.
+  static SimpleProgramPointTag Tag("MallocChecker : DeadSymbolsLeak");
+  ExplodedNode *N = C.addTransition(C.getState(), C.getPredecessor(), &Tag);
+
+  if (generateReport) {
+    for (llvm::SmallVector<SymbolRef, 2>::iterator
+         I = Errors.begin(), E = Errors.end(); I != E; ++I) {
+      reportLeak(*I, N, C);
+    }
+  }
+  C.addTransition(state->set<RegionState>(RS), N);
+}
+
+void MallocChecker::checkEndPath(CheckerContext &C) const {
+  ProgramStateRef state = C.getState();
+  RegionStateTy M = state->get<RegionState>();
+
+  // If inside inlined call, skip it.
+  if (C.getLocationContext()->getParent() != 0)
+    return;
+
+  for (RegionStateTy::iterator I = M.begin(), E = M.end(); I != E; ++I) {
+    RefState RS = I->second;
+    if (RS.isAllocated()) {
+      ExplodedNode *N = C.addTransition(state);
+      if (N)
+        reportLeak(I->first, N, C);
+    }
+  }
+}
+
+bool MallocChecker::checkEscape(SymbolRef Sym, const Stmt *S,
+                                CheckerContext &C) const {
+  ProgramStateRef state = C.getState();
+  const RefState *RS = state->get<RegionState>(Sym);
+  if (!RS)
+    return false;
+
+  if (RS->isAllocated()) {
+    state = state->set<RegionState>(Sym, RefState::getEscaped(S));
+    C.addTransition(state);
+    return true;
+  }
+  return false;
+}
+
+void MallocChecker::checkPreStmt(const CallExpr *CE, CheckerContext &C) const {
+  if (isMemFunction(C.getCalleeDecl(CE), C.getASTContext()))
+    return;
+
+  // Check use after free, when a freed pointer is passed to a call.
+  ProgramStateRef State = C.getState();
+  for (CallExpr::const_arg_iterator I = CE->arg_begin(),
+                                    E = CE->arg_end(); I != E; ++I) {
+    const Expr *A = *I;
+    if (A->getType().getTypePtr()->isAnyPointerType()) {
+      SymbolRef Sym = State->getSVal(A, C.getLocationContext()).getAsSymbol();
+      if (!Sym)
+        continue;
+      if (checkUseAfterFree(Sym, C, A))
+        return;
+    }
+  }
+}
+
+void MallocChecker::checkPreStmt(const ReturnStmt *S, CheckerContext &C) const {
+  const Expr *E = S->getRetValue();
+  if (!E)
+    return;
+
+  // Check if we are returning a symbol.
+  SVal RetVal = C.getState()->getSVal(E, C.getLocationContext());
+  SymbolRef Sym = RetVal.getAsSymbol();
+  if (!Sym)
+    // If we are returning a field of the allocated struct or an array element,
+    // the callee could still free the memory.
+    // TODO: This logic should be a part of generic symbol escape callback.
+    if (const MemRegion *MR = RetVal.getAsRegion())
+      if (isa<FieldRegion>(MR) || isa<ElementRegion>(MR))
+        if (const SymbolicRegion *BMR =
+              dyn_cast<SymbolicRegion>(MR->getBaseRegion()))
+          Sym = BMR->getSymbol();
+  if (!Sym)
+    return;
+
+  // Check if we are returning freed memory.
+  if (checkUseAfterFree(Sym, C, E))
+    return;
+
+  // If this function body is not inlined, check if the symbol is escaping.
+  if (C.getLocationContext()->getParent() == 0)
+    checkEscape(Sym, E, C);
+}
+
+// TODO: Blocks should be either inlined or should call invalidate regions
+// upon invocation. After that's in place, special casing here will not be 
+// needed.
+void MallocChecker::checkPostStmt(const BlockExpr *BE,
+                                  CheckerContext &C) const {
+
+  // Scan the BlockDecRefExprs for any object the retain count checker
+  // may be tracking.
+  if (!BE->getBlockDecl()->hasCaptures())
+    return;
+
+  ProgramStateRef state = C.getState();
+  const BlockDataRegion *R =
+    cast<BlockDataRegion>(state->getSVal(BE,
+                                         C.getLocationContext()).getAsRegion());
+
+  BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(),
+                                            E = R->referenced_vars_end();
+
+  if (I == E)
+    return;
+
+  SmallVector<const MemRegion*, 10> Regions;
+  const LocationContext *LC = C.getLocationContext();
+  MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager();
+
+  for ( ; I != E; ++I) {
+    const VarRegion *VR = *I;
+    if (VR->getSuperRegion() == R) {
+      VR = MemMgr.getVarRegion(VR->getDecl(), LC);
+    }
+    Regions.push_back(VR);
+  }
+
+  state =
+    state->scanReachableSymbols<StopTrackingCallback>(Regions.data(),
+                                    Regions.data() + Regions.size()).getState();
+  C.addTransition(state);
+}
+
+bool MallocChecker::checkUseAfterFree(SymbolRef Sym, CheckerContext &C,
+                                      const Stmt *S) const {
+  assert(Sym);
+  const RefState *RS = C.getState()->get<RegionState>(Sym);
+  if (RS && RS->isReleased()) {
+    if (ExplodedNode *N = C.generateSink()) {
+      if (!BT_UseFree)
+        BT_UseFree.reset(new BugType("Use-after-free", "Memory Error"));
+
+      BugReport *R = new BugReport(*BT_UseFree,
+                                   "Use of memory after it is freed",N);
+      if (S)
+        R->addRange(S->getSourceRange());
+      R->markInteresting(Sym);
+      R->addVisitor(new MallocBugVisitor(Sym));
+      C.EmitReport(R);
+      return true;
+    }
+  }
+  return false;
+}
+
+// Check if the location is a freed symbolic region.
+void MallocChecker::checkLocation(SVal l, bool isLoad, const Stmt *S,
+                                  CheckerContext &C) const {
+  SymbolRef Sym = l.getLocSymbolInBase();
+  if (Sym)
+    checkUseAfterFree(Sym, C);
+}
+
+//===----------------------------------------------------------------------===//
+// Check various ways a symbol can be invalidated.
+// TODO: This logic (the next 3 functions) is copied/similar to the
+// RetainRelease checker. We might want to factor this out.
+//===----------------------------------------------------------------------===//
+
+// Stop tracking symbols when a value escapes as a result of checkBind.
+// A value escapes in three possible cases:
+// (1) we are binding to something that is not a memory region.
+// (2) we are binding to a memregion that does not have stack storage
+// (3) we are binding to a memregion with stack storage that the store
+//     does not understand.
+void MallocChecker::checkBind(SVal loc, SVal val, const Stmt *S,
+                              CheckerContext &C) const {
+  // Are we storing to something that causes the value to "escape"?
+  bool escapes = true;
+  ProgramStateRef state = C.getState();
+
+  if (loc::MemRegionVal *regionLoc = dyn_cast<loc::MemRegionVal>(&loc)) {
+    escapes = !regionLoc->getRegion()->hasStackStorage();
+
+    if (!escapes) {
+      // To test (3), generate a new state with the binding added.  If it is
+      // the same state, then it escapes (since the store cannot represent
+      // the binding).
+      escapes = (state == (state->bindLoc(*regionLoc, val)));
+    }
+    if (!escapes) {
+      // Case 4: We do not currently model what happens when a symbol is
+      // assigned to a struct field, so be conservative here and let the symbol
+      // go. TODO: This could definitely be improved upon.
+      escapes = !isa<VarRegion>(regionLoc->getRegion());
+    }
+  }
+
+  // If our store can represent the binding and we aren't storing to something
+  // that doesn't have local storage then just return and have the simulation
+  // state continue as is.
+  if (!escapes)
+      return;
+
+  // Otherwise, find all symbols referenced by 'val' that we are tracking
+  // and stop tracking them.
+  state = state->scanReachableSymbols<StopTrackingCallback>(val).getState();
+  C.addTransition(state);
+}
+
+// If a symbolic region is assumed to NULL (or another constant), stop tracking
+// it - assuming that allocation failed on this path.
+ProgramStateRef MallocChecker::evalAssume(ProgramStateRef state,
+                                              SVal Cond,
+                                              bool Assumption) const {
+  RegionStateTy RS = state->get<RegionState>();
+  for (RegionStateTy::iterator I = RS.begin(), E = RS.end(); I != E; ++I) {
+    // If the symbol is assumed to NULL or another constant, this will
+    // return an APSInt*.
+    if (state->getSymVal(I.getKey()))
+      state = state->remove<RegionState>(I.getKey());
+  }
+
+  // Realloc returns 0 when reallocation fails, which means that we should
+  // restore the state of the pointer being reallocated.
+  ReallocMap RP = state->get<ReallocPairs>();
+  for (ReallocMap::iterator I = RP.begin(), E = RP.end(); I != E; ++I) {
+    // If the symbol is assumed to NULL or another constant, this will
+    // return an APSInt*.
+    if (state->getSymVal(I.getKey())) {
+      SymbolRef ReallocSym = I.getData().ReallocatedSym;
+      const RefState *RS = state->get<RegionState>(ReallocSym);
+      if (RS) {
+        if (RS->isReleased() && ! I.getData().IsFreeOnFailure)
+          state = state->set<RegionState>(ReallocSym,
+                             RefState::getAllocateUnchecked(RS->getStmt()));
+      }
+      state = state->remove<ReallocPairs>(I.getKey());
+    }
+  }
+
+  return state;
+}
+
+// Check if the function is known to us. So, for example, we could
+// conservatively assume it can free/reallocate it's pointer arguments.
+// (We assume that the pointers cannot escape through calls to system
+// functions not handled by this checker.)
+bool MallocChecker::doesNotFreeMemory(const CallOrObjCMessage *Call,
+                                      ProgramStateRef State) const {
+  if (!Call)
+    return false;
+
+  // For now, assume that any C++ call can free memory.
+  // TODO: If we want to be more optimistic here, we'll need to make sure that
+  // regions escape to C++ containers. They seem to do that even now, but for
+  // mysterious reasons.
+  if (Call->isCXXCall())
+    return false;
+
+  const Decl *D = Call->getDecl();
+  if (!D)
+    return false;
+
+  ASTContext &ASTC = State->getStateManager().getContext();
+
+  // If it's one of the allocation functions we can reason about, we model
+  // its behavior explicitly.
+  if (isa<FunctionDecl>(D) && isMemFunction(cast<FunctionDecl>(D), ASTC)) {
+    return true;
+  }
+
+  // If it's not a system call, assume it frees memory.
+  SourceManager &SM = ASTC.getSourceManager();
+  if (!SM.isInSystemHeader(D->getLocation()))
+    return false;
+
+  // Process C/ObjC functions.
+  if (const FunctionDecl *FD  = dyn_cast<FunctionDecl>(D)) {
+    // White list the system functions whose arguments escape.
+    const IdentifierInfo *II = FD->getIdentifier();
+    if (!II)
+      return true;
+    StringRef FName = II->getName();
+
+    // White list thread local storage.
+    if (FName.equals("pthread_setspecific"))
+      return false;
+
+    // White list the 'XXXNoCopy' ObjC functions.
+    if (FName.endswith("NoCopy")) {
+      // Look for the deallocator argument. We know that the memory ownership
+      // is not transfered only if the deallocator argument is
+      // 'kCFAllocatorNull'.
+      for (unsigned i = 1; i < Call->getNumArgs(); ++i) {
+        const Expr *ArgE = Call->getArg(i)->IgnoreParenCasts();
+        if (const DeclRefExpr *DE = dyn_cast<DeclRefExpr>(ArgE)) {
+          StringRef DeallocatorName = DE->getFoundDecl()->getName();
+          if (DeallocatorName == "kCFAllocatorNull")
+            return true;
+        }
+      }
+      return false;
+    }
+
+    // PR12101
+    // Many CoreFoundation and CoreGraphics might allow a tracked object 
+    // to escape.
+    if (Call->isCFCGAllowingEscape(FName))
+      return false;
+
+    // Associating streams with malloced buffers. The pointer can escape if
+    // 'closefn' is specified (and if that function does free memory).
+    // Currently, we do not inspect the 'closefn' function (PR12101).
+    if (FName == "funopen")
+      if (Call->getNumArgs() >= 4 && !Call->getArgSVal(4).isConstant(0))
+        return false;
+
+    // Do not warn on pointers passed to 'setbuf' when used with std streams,
+    // these leaks might be intentional when setting the buffer for stdio.
+    // http://stackoverflow.com/questions/2671151/who-frees-setvbuf-buffer
+    if (FName == "setbuf" || FName =="setbuffer" ||
+        FName == "setlinebuf" || FName == "setvbuf") {
+      if (Call->getNumArgs() >= 1)
+        if (const DeclRefExpr *Arg =
+              dyn_cast<DeclRefExpr>(Call->getArg(0)->IgnoreParenCasts()))
+          if (const VarDecl *D = dyn_cast<VarDecl>(Arg->getDecl()))
+              if (D->getCanonicalDecl()->getName().find("std")
+                                                   != StringRef::npos)
+                return false;
+    }
+
+    // A bunch of other functions, which take ownership of a pointer (See retain
+    // release checker). Not all the parameters here are invalidated, but the
+    // Malloc checker cannot differentiate between them. The right way of doing
+    // this would be to implement a pointer escapes callback.
+    if (FName == "CVPixelBufferCreateWithBytes" ||
+        FName == "CGBitmapContextCreateWithData" ||
+        FName == "CVPixelBufferCreateWithPlanarBytes" ||
+        FName == "OSAtomicEnqueue") {
+      return false;
+    }
+
+    // Whitelist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can
+    // be deallocated by NSMapRemove.
+    if (FName.startswith("NS") && (FName.find("Insert") != StringRef::npos))
+      return false;
+
+    // Otherwise, assume that the function does not free memory.
+    // Most system calls, do not free the memory.
+    return true;
+
+  // Process ObjC functions.
+  } else if (const ObjCMethodDecl * ObjCD = dyn_cast<ObjCMethodDecl>(D)) {
+    Selector S = ObjCD->getSelector();
+
+    // White list the ObjC functions which do free memory.
+    // - Anything containing 'freeWhenDone' param set to 1.
+    //   Ex: dataWithBytesNoCopy:length:freeWhenDone.
+    for (unsigned i = 1; i < S.getNumArgs(); ++i) {
+      if (S.getNameForSlot(i).equals("freeWhenDone")) {
+        if (Call->getArgSVal(i).isConstant(1))
+          return false;
+        else
+          return true;
+      }
+    }
+
+    // If the first selector ends with NoCopy, assume that the ownership is
+    // transfered as well.
+    // Ex:  [NSData dataWithBytesNoCopy:bytes length:10];
+    if (S.getNameForSlot(0).endswith("NoCopy")) {
+      return false;
+    }
+
+    // Otherwise, assume that the function does not free memory.
+    // Most system calls, do not free the memory.
+    return true;
+  }
+
+  // Otherwise, assume that the function can free memory.
+  return false;
+
+}
+
+// If the symbol we are tracking is invalidated, but not explicitly (ex: the &p
+// escapes, when we are tracking p), do not track the symbol as we cannot reason
+// about it anymore.
+ProgramStateRef
+MallocChecker::checkRegionChanges(ProgramStateRef State,
+                            const StoreManager::InvalidatedSymbols *invalidated,
+                                    ArrayRef<const MemRegion *> ExplicitRegions,
+                                    ArrayRef<const MemRegion *> Regions,
+                                    const CallOrObjCMessage *Call) const {
+  if (!invalidated || invalidated->empty())
+    return State;
+  llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols;
+
+  // If it's a call which might free or reallocate memory, we assume that all
+  // regions (explicit and implicit) escaped.
+
+  // Otherwise, whitelist explicit pointers; we still can track them.
+  if (!Call || doesNotFreeMemory(Call, State)) {
+    for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(),
+        E = ExplicitRegions.end(); I != E; ++I) {
+      if (const SymbolicRegion *R = (*I)->StripCasts()->getAs<SymbolicRegion>())
+        WhitelistedSymbols.insert(R->getSymbol());
+    }
+  }
+
+  for (StoreManager::InvalidatedSymbols::const_iterator I=invalidated->begin(),
+       E = invalidated->end(); I!=E; ++I) {
+    SymbolRef sym = *I;
+    if (WhitelistedSymbols.count(sym))
+      continue;
+    // The symbol escaped.
+    if (const RefState *RS = State->get<RegionState>(sym))
+      State = State->set<RegionState>(sym, RefState::getEscaped(RS->getStmt()));
+  }
+  return State;
+}
+
+static SymbolRef findFailedReallocSymbol(ProgramStateRef currState,
+                                         ProgramStateRef prevState) {
+  ReallocMap currMap = currState->get<ReallocPairs>();
+  ReallocMap prevMap = prevState->get<ReallocPairs>();
+
+  for (ReallocMap::iterator I = prevMap.begin(), E = prevMap.end();
+       I != E; ++I) {
+    SymbolRef sym = I.getKey();
+    if (!currMap.lookup(sym))
+      return sym;
+  }
+
+  return NULL;
+}
+
+PathDiagnosticPiece *
+MallocChecker::MallocBugVisitor::VisitNode(const ExplodedNode *N,
+                                           const ExplodedNode *PrevN,
+                                           BugReporterContext &BRC,
+                                           BugReport &BR) {
+  ProgramStateRef state = N->getState();
+  ProgramStateRef statePrev = PrevN->getState();
+
+  const RefState *RS = state->get<RegionState>(Sym);
+  const RefState *RSPrev = statePrev->get<RegionState>(Sym);
+  if (!RS && !RSPrev)
+    return 0;
+
+  const Stmt *S = 0;
+  const char *Msg = 0;
+  StackHintGeneratorForSymbol *StackHint = 0;
+
+  // Retrieve the associated statement.
+  ProgramPoint ProgLoc = N->getLocation();
+  if (isa<StmtPoint>(ProgLoc))
+    S = cast<StmtPoint>(ProgLoc).getStmt();
+  // If an assumption was made on a branch, it should be caught
+  // here by looking at the state transition.
+  if (isa<BlockEdge>(ProgLoc)) {
+    const CFGBlock *srcBlk = cast<BlockEdge>(ProgLoc).getSrc();
+    S = srcBlk->getTerminator();
+  }
+  if (!S)
+    return 0;
+
+  // Find out if this is an interesting point and what is the kind.
+  if (Mode == Normal) {
+    if (isAllocated(RS, RSPrev, S)) {
+      Msg = "Memory is allocated";
+      StackHint = new StackHintGeneratorForSymbol(Sym,
+                                                  "Returned allocated memory");
+    } else if (isReleased(RS, RSPrev, S)) {
+      Msg = "Memory is released";
+      StackHint = new StackHintGeneratorForSymbol(Sym,
+                                                  "Returned released memory");
+    } else if (isReallocFailedCheck(RS, RSPrev, S)) {
+      Mode = ReallocationFailed;
+      Msg = "Reallocation failed";
+      StackHint = new StackHintGeneratorForReallocationFailed(Sym,
+                                                       "Reallocation failed");
+
+      if (SymbolRef sym = findFailedReallocSymbol(state, statePrev)) {
+        // Is it possible to fail two reallocs WITHOUT testing in between?
+        assert((!FailedReallocSymbol || FailedReallocSymbol == sym) &&
+          "We only support one failed realloc at a time.");
+        BR.markInteresting(sym);
+        FailedReallocSymbol = sym;
+      }
+    }
+
+  // We are in a special mode if a reallocation failed later in the path.
+  } else if (Mode == ReallocationFailed) {
+    assert(FailedReallocSymbol && "No symbol to look for.");
+
+    // Is this is the first appearance of the reallocated symbol?
+    if (!statePrev->get<RegionState>(FailedReallocSymbol)) {
+      // If we ever hit this assert, that means BugReporter has decided to skip
+      // node pairs or visit them out of order.
+      assert(state->get<RegionState>(FailedReallocSymbol) &&
+        "Missed the reallocation point");
+
+      // We're at the reallocation point.
+      Msg = "Attempt to reallocate memory";
+      StackHint = new StackHintGeneratorForSymbol(Sym,
+                                                 "Returned reallocated memory");
+      FailedReallocSymbol = NULL;
+      Mode = Normal;
+    }
+  }
+
+  if (!Msg)
+    return 0;
+  assert(StackHint);
+
+  // Generate the extra diagnostic.
+  PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
+                             N->getLocationContext());
+  return new PathDiagnosticEventPiece(Pos, Msg, true, StackHint);
+}
+
+
+#define REGISTER_CHECKER(name) \
+void ento::register##name(CheckerManager &mgr) {\
+  registerCStringCheckerBasic(mgr); \
+  mgr.registerChecker<MallocChecker>()->Filter.C##name = true;\
+}
+
+REGISTER_CHECKER(MallocPessimistic)
+REGISTER_CHECKER(MallocOptimistic)