[Analyzer] Fix assertions in commit r246345 (pr22954).

[pgousseau]

Summary

Fix assertions kindly reported by Gabor Horvath and Piotr Zegar caused by commit r246345 and reverted in r246479.
Original review in http://reviews.llvm.org/D11832
Issue is caused by 'IsFirstBufInBound(...)' I wrongly assumed that no 'Unknown' values could reach it.
Added tests for unknown arguments being passed to 'memcpy' call.

Please let me know if this is an acceptable change ?

Regards,

Pierre Gousseau
SN-Systems - Sony Computer Entertainment

[dcoughlin]

lib/StaticAnalyzer/Checkers/CStringChecker.cpp

843 ↗

(On Diff #33838)

There doesn't seem to be a test that cares about this returning true (as compared to false).

855 ↗

(On Diff #33838)

There doesn't appear to be a test that cares about this returning true (as compared to false).

863 ↗

(On Diff #33838)

What's the rationale for treating the array access as in-bounds if the BufEnd is unknown? Or if LengthValue is unknown? Should these branches return false? Either way, can you add a comment explaining why this is the right thing to do and also update the doc comment of IsFirstBufInBound to reflect this behavior (e.g., "Returns true if destination buffer of copy function must/may be in bound")

lib/StaticAnalyzer/Core/RegionStore.cpp

1109 ↗

(On Diff #33838)

This assertion is triggering on our internal build bots. I'm working to get a reduced test case.

test/Analysis/pr22954.c

739 ↗

(On Diff #33838)

A question: how does this test tainted values?

[pgousseau]

lib/StaticAnalyzer/Checkers/CStringChecker.cpp

843 ↗

(On Diff #33838)

Will add thanks, f263 was the test meant for it.

855 ↗

(On Diff #33838)

Will add thanks, f34 was the test meant for it.

863 ↗

(On Diff #33838)

Yes I mean to return true in the case of an unknown array access to not warn on unknown state, will add comment thanks.

lib/StaticAnalyzer/Core/RegionStore.cpp

1109 ↗

(On Diff #33838)

I can replace the assert by an if statement meanwhile ?

test/Analysis/pr22954.c

739 ↗

(On Diff #33838)

Yes this comment is wrong, this is not testing tainted values. Will change comment and description thanks.

[pgousseau]

Following Devin's review:
Correct test for unknown length and unknown destination buffer.
Add comment to 'IsFirstBufInBound' behavior regarding unknown states.
Remove comments regarding tainted values.
Replace assertion regarding negative Region offset by an if statement.

Thanks for reviewing !

Pierre

[pgousseau]

Ping !

[dcoughlin]

lib/StaticAnalyzer/Checkers/CStringChecker.cpp

198 ↗

(On Diff #34359)

Since this returns true on unknown, it should be "may".

lib/StaticAnalyzer/Core/RegionStore.cpp

1109 ↗

(On Diff #34359)

I think it is important to figure out enough of why the assert was triggering so that we can add a test case for this 'if'. The preprocessed file that is failing our bots is from the bugzilla for PR13765, in the clang2 attachment.

You can reproduce with:

clang -cc1 -analyze -analyzer-checker=core,cplusplus -fcxx-exceptions -std=c++11 clang2/clang_crash_4pFspw.ii

[dcoughlin]

Here is a reduced test case:

class B {
public:
   B &operator= (const B &v) {
      return *this;
   }
};

class A {
  int a[1];
  B b;
};

typedef long int ptrdiff_t;

void copyInto(A *first, A *last, A *result) {
  ptrdiff_t n;
  for (n = last - first; n > 0; --n)
     *--result = *--last;
}

[pgousseau]

In D12571#248464, @dcoughlin wrote:

Here is a reduced test case:

Very useful thanks !

lib/StaticAnalyzer/Checkers/CStringChecker.cpp

198 ↗

(On Diff #34359)

Makes sense thanks !

lib/StaticAnalyzer/Core/RegionStore.cpp

1109 ↗

(On Diff #34359)

Will have a look !

[pgousseau]

Following Devin's review:

Fix a comment in 'IsFirstBufInBound'.
Remove incorrect assertion expecting 'RegionOffset::getOffset' to only return positives values.
Add test cases for regions having negatives offsets.

Updated a 'RegionOffset' class comment which seemed to suggest that 'RegionOffset::getOffset' could not return negative values.
Added test cases and handling for arrays' regions whose upper boundary can overflow.

Let me know if this is an acceptable change ?

Regards,

Pierre Gousseau

[dcoughlin]

Looks good to me! Thanks Pierre! I will commit.

[pgousseau]

In D12571#252366, @dcoughlin wrote:

Looks good to me! Thanks Pierre! I will commit.

Much appreciated thanks !

cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h

 class SymbolicRegion;
 class VarRegion;
 
 /// Represent a region's offset within the top level base region.
 class RegionOffset {
   /// The base region.
   const MemRegion *R;
 
-  /// The bit offset within the base region. It shouldn't be negative.
+  /// The bit offset within the base region. Can be negative.
   int64_t Offset;
 
 public:
   // We're using a const instead of an enumeration due to the size required;
   // Visual Studio will only create enumerations of size int, not long long.
   static const int64_t Symbolic = INT64_MAX;
 
   RegionOffset() : R(nullptr) {}
typedef llvm::DenseMap<SymbolRef, StorageTypeForKinds>::const_iterator
       const_symbol_iterator;
 
 public:
   /// \brief Describes different invalidation traits.
   enum InvalidationKinds {
     /// Tells that a region's contents is not changed.
     TK_PreserveContents = 0x1,
     /// Suppress pointer-escaping of a region.
-    TK_SuppressEscape = 0x2
+    TK_SuppressEscape = 0x2,
+    // Do not invalidate super region.
+    TK_DoNotInvalidateSuperRegion = 0x4
 
     // Do not forget to extend StorageTypeForKinds if number of traits exceed 
     // the number of bits StorageTypeForKinds can store.
   };
 
   void setTrait(SymbolRef Sym, InvalidationKinds IK);
   void setTrait(const MemRegion *MR, InvalidationKinds IK);
   bool hasTrait(SymbolRef Sym, InvalidationKinds IK);

cfe/trunk/lib/StaticAnalyzer/Checkers/CStringChecker.cpp

public:
   const StringLiteral *getCStringLiteral(CheckerContext &C,
                                          ProgramStateRef &state,
                                          const Expr *expr,
                                          SVal val) const;
 
   static ProgramStateRef InvalidateBuffer(CheckerContext &C,
                                           ProgramStateRef state,
                                           const Expr *Ex, SVal V,
-                                          bool IsSourceBuffer);
+                                          bool IsSourceBuffer,
+                                          const Expr *Size);
 
   static bool SummarizeRegion(raw_ostream &os, ASTContext &Ctx,
                               const MemRegion *MR);
 
   // Re-usable checks
   ProgramStateRef checkNonNull(CheckerContext &C,
                                    ProgramStateRef state,
                                    const Expr *S,
void emitOverlapBug(CheckerContext &C,
                       ProgramStateRef state,
                       const Stmt *First,
                       const Stmt *Second) const;
 
   ProgramStateRef checkAdditionOverflow(CheckerContext &C,
                                             ProgramStateRef state,
                                             NonLoc left,
                                             NonLoc right) const;
+
+  // Return true if the destination buffer of the copy function may be in bound.
+  // Expects SVal of Size to be positive and unsigned.
+  // Expects SVal of FirstBuf to be a FieldRegion.
+  static bool IsFirstBufInBound(CheckerContext &C,
+                                ProgramStateRef state,
+                                const Expr *FirstBuf,
+                                const Expr *Size);
 };
 
 } //end anonymous namespace
 
 REGISTER_MAP_WITH_PROGRAMSTATE(CStringLength, const MemRegion *, SVal)
 
 //===----------------------------------------------------------------------===//
 // Individual checks and utility methods.
const StringLiteral *CStringChecker::getCStringLiteral(CheckerContext &C,
   const StringRegion *strRegion= dyn_cast<StringRegion>(bufRegion);
   if (!strRegion)
     return nullptr;
 
   // Return the actual string in the string region.
   return strRegion->getStringLiteral();
 }
 
+bool CStringChecker::IsFirstBufInBound(CheckerContext &C,
+                                       ProgramStateRef state,
+                                       const Expr *FirstBuf,
+                                       const Expr *Size) {
+  // If we do not know that the buffer is long enough we return 'true'.
+  // Otherwise the parent region of this field region would also get
+  // invalidated, which would lead to warnings based on an unknown state.
+
+  // Originally copied from CheckBufferAccess and CheckLocation.
+  SValBuilder &svalBuilder = C.getSValBuilder();
+  ASTContext &Ctx = svalBuilder.getContext();
+  const LocationContext *LCtx = C.getLocationContext();
+
+  QualType sizeTy = Size->getType();
+  QualType PtrTy = Ctx.getPointerType(Ctx.CharTy);
+  SVal BufVal = state->getSVal(FirstBuf, LCtx);
+
+  SVal LengthVal = state->getSVal(Size, LCtx);
+  Optional<NonLoc> Length = LengthVal.getAs<NonLoc>();
+  if (!Length)
+    return true; // cf top comment.
+
+  // Compute the offset of the last element to be accessed: size-1.
+  NonLoc One = svalBuilder.makeIntVal(1, sizeTy).castAs<NonLoc>();
+  NonLoc LastOffset =
+      svalBuilder.evalBinOpNN(state, BO_Sub, *Length, One, sizeTy)
+          .castAs<NonLoc>();
+
+  // Check that the first buffer is sufficiently long.
+  SVal BufStart = svalBuilder.evalCast(BufVal, PtrTy, FirstBuf->getType());
+  Optional<Loc> BufLoc = BufStart.getAs<Loc>();
+  if (!BufLoc)
+    return true; // cf top comment.
+
+  SVal BufEnd =
+      svalBuilder.evalBinOpLN(state, BO_Add, *BufLoc, LastOffset, PtrTy);
+
+  // Check for out of bound array element access.
+  const MemRegion *R = BufEnd.getAsRegion();
+  if (!R)
+    return true; // cf top comment.
+
+  const ElementRegion *ER = dyn_cast<ElementRegion>(R);
+  if (!ER)
+    return true; // cf top comment.
+
+  assert(ER->getValueType() == C.getASTContext().CharTy &&
+         "IsFirstBufInBound should only be called with char* ElementRegions");
+
+  // Get the size of the array.
+  const SubRegion *superReg = cast<SubRegion>(ER->getSuperRegion());
+  SVal Extent =
+      svalBuilder.convertToArrayIndex(superReg->getExtent(svalBuilder));
+  DefinedOrUnknownSVal ExtentSize = Extent.castAs<DefinedOrUnknownSVal>();
+
+  // Get the index of the accessed element.
+  DefinedOrUnknownSVal Idx = ER->getIndex().castAs<DefinedOrUnknownSVal>();
+
+  ProgramStateRef StInBound = state->assumeInBound(Idx, ExtentSize, true);
+
+  return static_cast<bool>(StInBound);
+}
+
 ProgramStateRef CStringChecker::InvalidateBuffer(CheckerContext &C,
                                                  ProgramStateRef state,
                                                  const Expr *E, SVal V,
-                                                 bool IsSourceBuffer) {
+                                                 bool IsSourceBuffer,
+                                                 const Expr *Size) {
   Optional<Loc> L = V.getAs<Loc>();
   if (!L)
     return state;
 
   // FIXME: This is a simplified version of what's in CFRefCount.cpp -- it makes
   // some assumptions about the value that CFRefCount can't. Even so, it should
   // probably be refactored.
   if (Optional<loc::MemRegionVal> MR = L->getAs<loc::MemRegionVal>()) {
if (Optional<loc::MemRegionVal> MR = L->getAs<loc::MemRegionVal>()) {
     RegionAndSymbolInvalidationTraits ITraits;
     // Invalidate and escape only indirect regions accessible through the source
     // buffer.
     if (IsSourceBuffer) {
       ITraits.setTrait(R,
                        RegionAndSymbolInvalidationTraits::TK_PreserveContents);
       ITraits.setTrait(R, RegionAndSymbolInvalidationTraits::TK_SuppressEscape);
       CausesPointerEscape = true;
+    } else {
+      const MemRegion::Kind& K = R->getKind();
+      if (K == MemRegion::FieldRegionKind)
+        if (Size && IsFirstBufInBound(C, state, E, Size)) {
+          // If destination buffer is a field region and access is in bound,
+          // do not invalidate its super region.
+          ITraits.setTrait(
+              R,
+              RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion);
+        }
     }
 
     return state->invalidateRegions(R, E, C.blockCount(), LCtx,
                                     CausesPointerEscape, nullptr, nullptr,
                                     &ITraits);
   }
 
   // If we have a non-region value by chance, just remove the binding.
if (stateNonZeroSize) {
 
     // Invalidate the destination (regular invalidation without pointer-escaping
     // the address of the top-level region).
     // FIXME: Even if we can't perfectly model the copy, we should see if we
     // can use LazyCompoundVals to copy the source values into the destination.
     // This would probably remove any existing bindings past the end of the
     // copied region, but that's still an improvement over blank invalidation.
     state = InvalidateBuffer(C, state, Dest, C.getSVal(Dest),
-                             /*IsSourceBuffer*/false);
+                             /*IsSourceBuffer*/false, Size);
 
     // Invalidate the source (const-invalidation without const-pointer-escaping
     // the address of the top-level region).
     state = InvalidateBuffer(C, state, Source, C.getSVal(Source),
-                             /*IsSourceBuffer*/true);
+                             /*IsSourceBuffer*/true, nullptr);
 
     C.addTransition(state);
   }
 }
 
 
 void CStringChecker::evalMemcpy(CheckerContext &C, const CallExpr *CE) const {
   if (CE->getNumArgs() < 3)
if (Optional<loc::MemRegionVal> dstRegVal =
     // Invalidate the destination (regular invalidation without pointer-escaping
     // the address of the top-level region). This must happen before we set the
     // C string length because invalidation will clear the length.
     // FIXME: Even if we can't perfectly model the copy, we should see if we
     // can use LazyCompoundVals to copy the source values into the destination.
     // This would probably remove any existing bindings past the end of the
     // string, but that's still an improvement over blank invalidation.
     state = InvalidateBuffer(C, state, Dst, *dstRegVal,
-                             /*IsSourceBuffer*/false);
+                             /*IsSourceBuffer*/false, nullptr);
 
     // Invalidate the source (const-invalidation without const-pointer-escaping
     // the address of the top-level region).
-    state = InvalidateBuffer(C, state, srcExpr, srcVal, /*IsSourceBuffer*/true);
+    state = InvalidateBuffer(C, state, srcExpr, srcVal, /*IsSourceBuffer*/true,
+                             nullptr);
 
     // Set the C string length of the destination, if we know it.
     if (isBounded && !isAppending) {
       // strncpy is annoying in that it doesn't guarantee to null-terminate
       // the result string. If the original string didn't fit entirely inside
       // the bound (including the null-terminator), we don't know how long the
       // result is.
       if (amountCopied != strLength)
void CStringChecker::evalStrsep(CheckerContext &C, const CallExpr *CE) const {
   SVal Result;
   if (Optional<Loc> SearchStrLoc = SearchStrVal.getAs<Loc>()) {
     // Get the current value of the search string pointer, as a char*.
     Result = State->getSVal(*SearchStrLoc, CharPtrTy);
 
     // Invalidate the search string, representing the change of one delimiter
     // character to NUL.
     State = InvalidateBuffer(C, State, SearchStrPtr, Result,
-                             /*IsSourceBuffer*/false);
+                             /*IsSourceBuffer*/false, nullptr);
 
     // Overwrite the search string pointer. The new value is either an address
     // further along in the same string, or NULL if there are no more tokens.
     State = State->bindLoc(*SearchStrLoc,
                            SVB.conjureSymbolVal(getTag(), CE, LCtx, CharPtrTy,
                                                 C.blockCount()));
   } else {
     assert(SearchStrVal.isUnknown());

cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp

public:
   bool AddToWorkList(WorkListElement E, const ClusterBindings *C) {
     if (C && !Visited.insert(C).second)
       return false;
     WL.push_back(E);
     return true;
   }
 
   bool AddToWorkList(const MemRegion *R) {
-    const MemRegion *BaseR = R->getBaseRegion();
-    return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
+    return static_cast<DERIVED*>(this)->AddToWorkList(R);
   }
 
   void RunWorkList() {
     while (!WL.empty()) {
       WorkListElement E = WL.pop_back_val();
       const MemRegion *BaseR = E;
 
       static_cast<DERIVED*>(this)->VisitCluster(BaseR, getCluster(BaseR));
invalidateRegionsWorker(RegionStoreManager &rm,
                           RegionAndSymbolInvalidationTraits &ITraitsIn,
                           StoreManager::InvalidatedRegions *r,
                           GlobalsFilterKind GFK)
     : ClusterAnalysis<invalidateRegionsWorker>(rm, stateMgr, b, GFK),
       Ex(ex), Count(count), LCtx(lctx), IS(is), ITraits(ITraitsIn), Regions(r){}
 
   void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
   void VisitBinding(SVal V);
+
+  using ClusterAnalysis::AddToWorkList;
+
+  bool AddToWorkList(const MemRegion *R);
 };
 }
 
+bool invalidateRegionsWorker::AddToWorkList(const MemRegion *R) {
+  bool doNotInvalidateSuperRegion = ITraits.hasTrait(
+      R, RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion);
+  const MemRegion *BaseR = doNotInvalidateSuperRegion ? R : R->getBaseRegion();
+  return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
+}
+
 void invalidateRegionsWorker::VisitBinding(SVal V) {
   // A symbol?  Mark it touched by the invalidation.
   if (SymbolRef Sym = V.getAsSymbol())
     IS.insert(Sym);
 
   if (const MemRegion *R = V.getAsRegion()) {
     AddToWorkList(R);
     return;
if (T->isStructureOrClassType()) {
     // conjured symbol. The type of the symbol is irrelevant.
     DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
                                                           Ctx.IntTy, Count);
     B = B.addBinding(baseR, BindingKey::Default, V);
     return;
   }
 
   if (const ArrayType *AT = Ctx.getAsArrayType(T)) {
+    bool doNotInvalidateSuperRegion = ITraits.hasTrait(
+        baseR,
+        RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion);
+
+    if (doNotInvalidateSuperRegion) {
+      // We are not doing blank invalidation of the whole array region so we
+      // have to manually invalidate each elements.
+      Optional<uint64_t> NumElements;
+
+      // Compute lower and upper offsets for region within array.
+      if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT))
+        NumElements = CAT->getSize().getZExtValue();
+      if (!NumElements) // We are not dealing with a constant size array
+        goto conjure_default;
+      QualType ElementTy = AT->getElementType();
+      uint64_t ElemSize = Ctx.getTypeSize(ElementTy);
+      const RegionOffset &RO = baseR->getAsOffset();
+      const MemRegion *SuperR = baseR->getBaseRegion();
+      if (RO.hasSymbolicOffset()) {
+        // If base region has a symbolic offset,
+        // we revert to invalidating the super region.
+        if (SuperR)
+          AddToWorkList(SuperR);
+        goto conjure_default;
+      }
+
+      uint64_t LowerOffset = RO.getOffset();
+      uint64_t UpperOffset = LowerOffset + *NumElements * ElemSize;
+      bool UpperOverflow = UpperOffset < LowerOffset;
+
+      // Invalidate regions which are within array boundaries,
+      // or have a symbolic offset.
+      if (!SuperR)
+        goto conjure_default;
+
+      const ClusterBindings *C = B.lookup(SuperR);
+      if (!C)
+        goto conjure_default;
+
+      for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E;
+           ++I) {
+        const BindingKey &BK = I.getKey();
+        Optional<uint64_t> ROffset =
+            BK.hasSymbolicOffset() ? Optional<uint64_t>() : BK.getOffset();
+
+        // Check offset is not symbolic and within array's boundaries.
+        // Handles arrays of 0 elements and of 0-sized elements as well.
+        if (!ROffset ||
+            (ROffset &&
+             ((*ROffset >= LowerOffset && *ROffset < UpperOffset) ||
+              (UpperOverflow &&
+               (*ROffset >= LowerOffset || *ROffset < UpperOffset)) ||
+              (LowerOffset == UpperOffset && *ROffset == LowerOffset)))) {
+          B = B.removeBinding(I.getKey());
+          // Bound symbolic regions need to be invalidated for dead symbol
+          // detection.
+          SVal V = I.getData();
+          const MemRegion *R = V.getAsRegion();
+          if (R && isa<SymbolicRegion>(R))
+            VisitBinding(V);
+        }
+      }
+    }
+  conjure_default:
       // Set the default value of the array to conjured symbol.
     DefinedOrUnknownSVal V =
     svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
                                      AT->getElementType(), Count);
     B = B.addBinding(baseR, BindingKey::Default, V);
     return;
   }
 
removeDeadBindingsWorker(RegionStoreManager &rm,
     : ClusterAnalysis<removeDeadBindingsWorker>(rm, stateMgr, b, GFK_None),
       SymReaper(symReaper), CurrentLCtx(LCtx) {}
 
   // Called by ClusterAnalysis.
   void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C);
   void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
   using ClusterAnalysis<removeDeadBindingsWorker>::VisitCluster;
 
+  using ClusterAnalysis::AddToWorkList;
+
+  bool AddToWorkList(const MemRegion *R);
+
   bool UpdatePostponed();
   void VisitBinding(SVal V);
 };
 }
 
+bool removeDeadBindingsWorker::AddToWorkList(const MemRegion *R) {
+  const MemRegion *BaseR = R->getBaseRegion();
+  return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
+}
+
 void removeDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR,
                                                    const ClusterBindings &C) {
 
   if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) {
     if (SymReaper.isLive(VR))
       AddToWorkList(baseR, &C);
 
     return;

cfe/trunk/test/Analysis/pr22954.c

+// Given code 'struct aa { char s1[4]; char * s2;} a; memcpy(a.s1, ...);',
+// this test checks that the CStringChecker only invalidates the destination buffer array a.s1 (instead of a.s1 and a.s2).
+// At the moment the whole of the destination array content is invalidated.
+// If a.s1 region has a symbolic offset, the whole region of 'a' is invalidated.
+// Specific triple set to test structures of size 0.
+// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -analyze -analyzer-checker=core,unix.Malloc,debug.ExprInspection -analyzer-store=region -verify %s
+
+typedef __typeof(sizeof(int)) size_t;
+
+char *strdup(const char *s);
+void free(void *);
+void *memcpy(void *dst, const void *src, size_t n); // expected-note{{passing argument to parameter 'dst' here}}
+void *malloc(size_t n);
+
+void clang_analyzer_eval(int);
+
+struct aa {
+    char s1[4];
+    char *s2;
+};
+
+// Test different types of structure initialisation.
+int f0() {
+  struct aa a0 = {{1, 2, 3, 4}, 0};
+  a0.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(a0.s1, input, 4);
+  clang_analyzer_eval(a0.s1[0] == 'a'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a0.s1[1] == 'b'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a0.s1[2] == 'c'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a0.s1[3] == 'd'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a0.s2 == 0); // expected-warning{{UNKNOWN}}
+  free(a0.s2); // no warning
+  return 0;
+}
+
+int f1() {
+  struct aa a1;
+  a1.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(a1.s1, input, 4);
+  clang_analyzer_eval(a1.s1[0] == 'a'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a1.s1[1] == 'b'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a1.s1[2] == 'c'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a1.s1[3] == 'd'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a1.s2 == 0); // expected-warning{{UNKNOWN}}
+  free(a1.s2); // no warning
+  return 0;
+}
+
+int f2() {
+  struct aa a2 = {{1, 2}};
+  a2.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(a2.s1, input, 4);
+  clang_analyzer_eval(a2.s1[0] == 'a'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a2.s1[1] == 'b'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a2.s1[2] == 'c'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a2.s1[3] == 'd'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a2.s2 == 0); // expected-warning{{UNKNOWN}}
+  free(a2.s2); // no warning
+  return 0;
+}
+
+int f3() {
+  struct aa a3 = {{1, 2, 3, 4}, 0};
+  a3.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  int * dest = (int*)a3.s1;
+  memcpy(dest, input, 4);
+  clang_analyzer_eval(a3.s1[0] == 'a'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(dest[0] == 'a'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a3.s1[1] == 'b'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(dest[1] == 'b'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a3.s1[2] == 'c'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(dest[2] == 'c'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a3.s1[3] == 'd'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(dest[3] == 'd'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a3.s2 == 0); // expected-warning{{UNKNOWN}}
+  free(a3.s2); // no warning
+  return 0;
+}
+
+struct bb {
+  struct aa a;
+  char * s2;
+};
+
+int f4() {
+  struct bb b0 = {{1, 2, 3, 4}, 0};
+  b0.s2 = strdup("hello");
+  b0.a.s2 = strdup("hola");
+  char input[] = {'a', 'b', 'c', 'd'};
+  char * dest = (char*)(b0.a.s1);
+  memcpy(dest, input, 4);
+  clang_analyzer_eval(b0.a.s1[0] == 'a'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(dest[0] == 'a'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(b0.a.s1[1] == 'b'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(dest[1] == 'b'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(b0.a.s1[2] == 'c'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(dest[2] == 'c'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(b0.a.s1[3] == 'd'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(dest[3] == 'd'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(b0.s2 == 0); // expected-warning{{UNKNOWN}}
+  free(b0.a.s2); // no warning
+  free(b0.s2); // no warning
+  return 0;
+}
+
+// Test that memory leaks are caught.
+int f5() {
+  struct aa a0 = {{1, 2, 3, 4}, 0};
+  a0.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(a0.s1, input, 4);
+  return 0; // expected-warning{{Potential leak of memory pointed to by 'a0.s2'}}
+}
+
+int f6() {
+  struct aa a1;
+  a1.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(a1.s1, input, 4);
+  return 0; // expected-warning{{Potential leak of memory pointed to by 'a1.s2'}}
+}
+
+int f7() {
+  struct aa a2 = {{1, 2}};
+  a2.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(a2.s1, input, 4);
+  return 0; // expected-warning{{Potential leak of memory pointed to by 'a2.s2'}}
+}
+
+int f8() {
+  struct aa a3 = {{1, 2, 3, 4}, 0};
+  a3.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  int * dest = (int*)a3.s1;
+  memcpy(dest, input, 4);
+  return 0; // expected-warning{{Potential leak of memory pointed to by 'a3.s2'}}
+}
+
+int f9() {
+  struct bb b0 = {{1, 2, 3, 4}, 0};
+  b0.s2 = strdup("hello");
+  b0.a.s2 = strdup("hola");
+  char input[] = {'a', 'b', 'c', 'd'};
+  char * dest = (char*)(b0.a.s1);
+  memcpy(dest, input, 4);
+  free(b0.a.s2); // expected-warning{{Potential leak of memory pointed to by 'b0.s2'}}
+  return 0;
+}
+
+int f10() {
+  struct bb b0 = {{1, 2, 3, 4}, 0};
+  b0.s2 = strdup("hello");
+  b0.a.s2 = strdup("hola");
+  char input[] = {'a', 'b', 'c', 'd'};
+  char * dest = (char*)(b0.a.s1);
+  memcpy(dest, input, 4);
+  free(b0.s2); // expected-warning{{Potential leak of memory pointed to by 'b0.a.s2'}}
+  return 0;
+}
+
+// Test invalidating fields being addresses of array.
+struct cc {
+  char * s1;
+  char * s2;
+};
+
+int f11() {
+  char x[4] = {1, 2};
+  x[0] = 1;
+  x[1] = 2;
+  struct cc c0;
+  c0.s2 = strdup("hello");
+  c0.s1 = &x[0];
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(c0.s1, input, 4);
+  clang_analyzer_eval(x[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(x[1] == 2); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(c0.s1[0] == 'a'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(c0.s1[1] == 'b'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(c0.s1[2] == 'c'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(c0.s1[3] == 'd'); // expected-warning{{UNKNOWN}}
+  free(c0.s2); // no-warning
+  return 0;
+}
+
+// Test inverting field position between s1 and s2.
+struct dd {
+  char *s2;
+  char s1[4];
+};
+
+int f12() {
+  struct dd d0 = {0, {1, 2, 3, 4}};
+  d0.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(d0.s1, input, 4);
+  clang_analyzer_eval(d0.s1[0] == 'a'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(d0.s1[1] == 'b'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(d0.s1[2] == 'c'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(d0.s1[3] == 'd'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(d0.s2 == 0); // expected-warning{{UNKNOWN}}
+  free(d0.s2); // no warning
+  return 0;
+}
+
+// Test arrays of structs.
+struct ee {
+  int a;
+  char b;
+};
+
+struct EE {
+  struct ee s1[2];
+  char * s2;
+};
+
+int f13() {
+  struct EE E0 = {{{1, 2}, {3, 4}}, 0};
+  E0.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(E0.s1, input, 4);
+  clang_analyzer_eval(E0.s1[0].a == 'a'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(E0.s1[0].b == 'b'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(E0.s1[1].a == 'c'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(E0.s1[1].b == 'd'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(E0.s2 == 0); // expected-warning{{UNKNOWN}}
+  free(E0.s2); // no warning
+  return 0;
+}
+
+// Test global parameters.
+struct aa a15 = {{1, 2, 3, 4}, 0};
+
+int f15() {
+  a15.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(a15.s1, input, 4);
+  clang_analyzer_eval(a15.s1[0] == 'a'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a15.s1[1] == 'b'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a15.s1[2] == 'c'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a15.s1[3] == 'd'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a15.s2 == 0); // expected-warning{{UNKNOWN}}
+  free(a15.s2); // no warning
+  return 0;
+}
+
+// Test array of 0 sized elements.
+struct empty {};
+struct gg {
+  struct empty s1[4];
+  char * s2;
+};
+
+int f16() {
+  struct gg g0 = {{}, 0};
+  g0.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(g0.s1, input, 4);
+  clang_analyzer_eval(*(int*)(&g0.s1[0]) == 'a'); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by 'g0.s2'}}
+  clang_analyzer_eval(*(int*)(&g0.s1[1]) == 'b'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(*(int*)(&g0.s1[2]) == 'c'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(*(int*)(&g0.s1[3]) == 'd'); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(g0.s2 == 0); // expected-warning{{UNKNOWN}}
+  free(g0.s2); // no warning
+  return 0;
+}
+
+// Test array of 0 elements.
+struct hh {
+  char s1[0];
+  char * s2;
+};
+
+int f17() {
+  struct hh h0;
+  h0.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(h0.s1, input, 4);
+  clang_analyzer_eval(h0.s1[0] == 'a'); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by 'h0.s2'}}
+  clang_analyzer_eval(h0.s2 == 0); // expected-warning{{UNKNOWN}}
+  free(h0.s2); // no warning
+  return 0;
+}
+
+// Test writing past the array.
+struct ii {
+  char s1[4];
+  int i;
+  int j;
+  char * s2;
+};
+
+int f18() {
+  struct ii i18 = {{1, 2, 3, 4}, 5, 6};
+  i18.i = 10;
+  i18.j = 11;
+  i18.s2 = strdup("hello");
+  char input[100] = {3};
+  memcpy(i18.s1, input, 100);
+  clang_analyzer_eval(i18.s1[0] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by 'i18.s2'}}
+  clang_analyzer_eval(i18.s1[1] == 2); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(i18.s1[2] == 3); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(i18.s1[3] == 4); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(i18.i == 10); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(i18.j == 11); // expected-warning{{UNKNOWN}}
+  return 0;
+}
+
+int f181() {
+  struct ii i181 = {{1, 2, 3, 4}, 5, 6};
+  i181.i = 10;
+  i181.j = 11;
+  i181.s2 = strdup("hello");
+  char input[100] = {3};
+  memcpy(i181.s1, input, 5); // invalidate the whole region of i181
+  clang_analyzer_eval(i181.s1[0] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by 'i181.s2'}}
+  clang_analyzer_eval(i181.s1[1] == 2); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(i181.s1[2] == 3); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(i181.s1[3] == 4); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(i181.i == 10); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(i181.j == 11); // expected-warning{{UNKNOWN}}
+  return 0;
+}
+
+// Test array with a symbolic offset.
+struct jj {
+  char s1[2];
+  char * s2;
+};
+
+struct JJ {
+  struct jj s1[3];
+  char * s2;
+};
+
+int f19(int i) {
+  struct JJ J0 = {{{1, 2, 0}, {3, 4, 0}, {5, 6, 0}}, 0};
+  J0.s2 = strdup("hello");
+  J0.s1[0].s2 = strdup("hello");
+  J0.s1[1].s2 = strdup("hi");
+  J0.s1[2].s2 = strdup("world");
+  char input[2] = {'a', 'b'};
+  memcpy(J0.s1[i].s1, input, 2);
+  clang_analyzer_eval(J0.s1[0].s1[0] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by field 's2'}}\
+  expected-warning{{Potential leak of memory pointed to by 'J0.s2'}}
+  clang_analyzer_eval(J0.s1[0].s1[1] == 2); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(J0.s1[1].s1[0] == 3); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(J0.s1[1].s1[1] == 4); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(J0.s1[2].s1[0] == 5); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(J0.s1[2].s1[1] == 6); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(J0.s1[i].s1[0] == 5); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(J0.s1[i].s1[1] == 6); // expected-warning{{UNKNOWN}}
+  // FIXME: memory leak warning for J0.s2 should be emitted here instead of after memcpy call.
+  return 0; // no warning
+}
+
+// Test array with its super region having symbolic offseted regions.
+int f20(int i) {
+  struct aa * a20 = malloc(sizeof(struct aa) * 2);
+  a20[0].s1[0] = 1;
+  a20[0].s1[1] = 2;
+  a20[0].s1[2] = 3;
+  a20[0].s1[3] = 4;
+  a20[0].s2 = strdup("hello");
+  a20[1].s1[0] = 5;
+  a20[1].s1[1] = 6;
+  a20[1].s1[2] = 7;
+  a20[1].s1[3] = 8;
+  a20[1].s2 = strdup("world");
+  a20[i].s2 = strdup("hola");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(a20[0].s1, input, 4);
+  clang_analyzer_eval(a20[0].s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[0].s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[0].s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[0].s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[0].s2 == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[1].s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[1].s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[1].s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[1].s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[1].s2 == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[i].s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[i].s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[i].s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[i].s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a20[i].s2 == 0); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by 'a20'}}
+
+  return 0;
+}
+
+// Test array's region and super region both having symbolic offsets.
+int f21(int i) {
+  struct aa * a21 = malloc(sizeof(struct aa) * 2);
+  a21[0].s1[0] = 1;
+  a21[0].s1[1] = 2;
+  a21[0].s1[2] = 3;
+  a21[0].s1[3] = 4;
+  a21[0].s2 = 0;
+  a21[1].s1[0] = 5;
+  a21[1].s1[1] = 6;
+  a21[1].s1[2] = 7;
+  a21[1].s1[3] = 8;
+  a21[1].s2 = 0;
+  a21[i].s2 = strdup("hello");
+  a21[i].s1[0] = 1;
+  a21[i].s1[1] = 2;
+  a21[i].s1[2] = 3;
+  a21[i].s1[3] = 4;
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(a21[i].s1, input, 4);
+  clang_analyzer_eval(a21[0].s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[0].s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[0].s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[0].s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[0].s2 == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[1].s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[1].s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[1].s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[1].s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[1].s2 == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[i].s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[i].s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[i].s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[i].s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a21[i].s2 == 0); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by 'a21'}}
+
+  return 0;
+}
+
+// Test regions aliasing other regions.
+struct ll {
+  char s1[4];
+  char * s2;
+};
+
+struct mm {
+  char s3[4];
+  char * s4;
+};
+
+int f24() {
+  struct ll l24 = {{1, 2, 3, 4}, 0};
+  struct mm * m24 = (struct mm *)&l24;
+  m24->s4 = strdup("hello");
+  char input[] = {1, 2, 3, 4};
+  memcpy(m24->s3, input, 4);
+  clang_analyzer_eval(m24->s3[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m24->s3[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m24->s3[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m24->s3[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(l24.s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(l24.s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(l24.s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(l24.s1[3] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by field 's4'}}
+  return 0;
+}
+
+// Test region with potential aliasing and symbolic offsets.
+// Store assumes no aliasing.
+int f25(int i, int j, struct ll * l, struct mm * m) {
+  m->s4 = strdup("hola"); // m->s4 not tracked
+  m->s3[0] = 1;
+  m->s3[1] = 2;
+  m->s3[2] = 3;
+  m->s3[3] = 4;
+  m->s3[j] = 5; // invalidates m->s3
+  l->s2 = strdup("hello"); // l->s2 not tracked
+  l->s1[0] = 6;
+  l->s1[1] = 7;
+  l->s1[2] = 8;
+  l->s1[3] = 9;
+  l->s1[i] = 10; // invalidates l->s1
+  char input[] = {1, 2, 3, 4};
+  memcpy(m->s3, input, 4); // does not invalidate l->s1[i]
+  clang_analyzer_eval(m->s3[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m->s3[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m->s3[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m->s3[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m->s3[i] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m->s3[j] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(l->s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(l->s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(l->s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(l->s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(l->s1[i] == 1); // expected-warning{{FALSE}}
+  clang_analyzer_eval(l->s1[j] == 1); // expected-warning{{UNKNOWN}}
+  return 0;
+}
+
+// Test size with symbolic size argument.
+int f26(int i) {
+  struct aa a26 = {{1, 2, 3, 4}, 0};
+  a26.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(a26.s1, input, i); // i assumed in bound
+  clang_analyzer_eval(a26.s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a26.s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a26.s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a26.s1[3] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by 'a26.s2'}}
+  return 0;
+}
+
+// Test sizeof as a size argument.
+int f261() {
+  struct aa a261 = {{1, 2, 3, 4}, 0};
+  a261.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(a261.s1, input, sizeof(a261.s1));
+  clang_analyzer_eval(a261.s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a261.s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a261.s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a261.s1[3] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by 'a261.s2'}}
+  return 0;
+}
+
+// Test negative size argument.
+int f262() {
+  struct aa a262 = {{1, 2, 3, 4}, 0};
+  a262.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(a262.s1, input, -1);
+  clang_analyzer_eval(a262.s1[0] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by 'a262.s2'}}
+  clang_analyzer_eval(a262.s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a262.s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(a262.s1[3] == 1); // expected-warning{{UNKNOWN}}
+  return 0;
+}
+
+// Test size argument being an unknown value.
+struct xx {
+  char s1[4];
+  char * s2;
+};
+
+int f263(int n, char * len) {
+  struct xx x263 = {0};
+  x263.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(x263.s1, input, *(len + n));
+  clang_analyzer_eval(x263.s1[0] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(x263.s1[1] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(x263.s1[2] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(x263.s1[3] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(x263.s2 == 0); // expected-warning{{UNKNOWN}}
+  return 0; // expected-warning{{Potential leak of memory pointed to by 'x263.s2'}}
+}
+
+
+// Test casting regions with symbolic offseted sub regions.
+int f27(int i) {
+  struct mm m27 = {{1, 2, 3, 4}, 0};
+  m27.s4 = strdup("hello");
+  m27.s3[i] = 5;
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(((struct ll*)(&m27))->s1, input, 4);
+  clang_analyzer_eval(m27.s3[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m27.s3[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m27.s3[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m27.s3[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m27.s3[i] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by 'm27.s4'}}
+  return 0;
+}
+
+int f28(int i, int j, int k, int l) {
+  struct mm m28[2];
+  m28[i].s4 = strdup("hello");
+  m28[j].s3[k] = 1;
+  struct ll * l28 = (struct ll*)(&m28[1]);
+  l28->s1[l] = 2;
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(l28->s1, input, 4);
+  clang_analyzer_eval(m28[0].s3[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m28[0].s3[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m28[0].s3[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m28[0].s3[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m28[1].s3[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m28[1].s3[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m28[1].s3[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m28[1].s3[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m28[i].s3[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m28[i].s3[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m28[i].s3[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m28[i].s3[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m28[j].s3[k] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(l28->s1[l] == 2); // expected-warning{{UNKNOWN}}
+  return 0;
+}
+
+int f29(int i, int j, int k, int l, int m) {
+  struct mm m29[2];
+  m29[i].s4 = strdup("hello");
+  m29[j].s3[k] = 1;
+  struct ll * l29 = (struct ll*)(&m29[l]);
+  l29->s1[m] = 2;
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(l29->s1, input, 4);
+  clang_analyzer_eval(m29[0].s3[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m29[0].s3[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m29[0].s3[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m29[0].s3[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m29[1].s3[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m29[1].s3[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m29[1].s3[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m29[1].s3[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m29[i].s3[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m29[i].s3[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m29[i].s3[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m29[i].s3[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(m29[j].s3[k] == 1); // expected-warning{{TRUE}}\
+  expected-warning{{Potential leak of memory pointed to by field 's4'}}
+  clang_analyzer_eval(l29->s1[m] == 2); // expected-warning{{UNKNOWN}}
+  return 0;
+}
+
+// Test unions' fields.
+union uu {
+  char x;
+  char s1[4];
+};
+
+int f30() {
+  union uu u30 = { .s1 = {1, 2, 3, 4}};
+  char input[] = {1, 2, 3, 4};
+  memcpy(u30.s1, input, 4);
+  clang_analyzer_eval(u30.s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(u30.s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(u30.s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(u30.s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(u30.x == 1); // expected-warning{{UNKNOWN}}
+  return 0;
+}
+
+struct kk {
+  union uu u;
+  char * s2;
+};
+
+int f31() {
+  struct kk k31;
+  k31.s2 = strdup("hello");
+  k31.u.x = 1;
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(k31.u.s1, input, 4);
+  clang_analyzer_eval(k31.u.s1[0] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by 'k31.s2'}}
+  clang_analyzer_eval(k31.u.s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(k31.u.s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(k31.u.s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(k31.u.x == 1); // expected-warning{{UNKNOWN}}
+  // FIXME: memory leak warning for k31.s2 should be emitted here.
+  return 0;
+}
+
+union vv {
+  int x;
+  char * s2;
+};
+
+int f32() {
+  union vv v32;
+  v32.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(v32.s2, input, 4);
+  clang_analyzer_eval(v32.s2[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(v32.s2[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(v32.s2[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(v32.s2[3] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{Potential leak of memory pointed to by 'v32.s2'}}
+  return 0;
+}
+
+struct nn {
+  int s1;
+  int i;
+  int j;
+  int k;
+  char * s2;
+};
+
+// Test bad types to dest buffer.
+int f33() {
+  struct nn n33 = {1, 2, 3, 4, 0};
+  n33.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(n33.s1, input, 4); // expected-warning{{incompatible integer to pointer conversion passing 'int' to parameter of type 'void *'}}
+  clang_analyzer_eval(n33.i == 2); // expected-warning{{TRUE}}
+  clang_analyzer_eval(n33.j == 3); // expected-warning{{TRUE}}
+  clang_analyzer_eval(n33.k == 4); // expected-warning{{TRUE}}
+  clang_analyzer_eval(((char*)(n33.s1))[0] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{cast to 'char *' from smaller integer type 'int'}}
+  clang_analyzer_eval(((char*)(n33.s1))[1] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{cast to 'char *' from smaller integer type 'int'}}
+  clang_analyzer_eval(((char*)(n33.s1))[2] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{cast to 'char *' from smaller integer type 'int'}}
+  clang_analyzer_eval(((char*)(n33.s1))[3] == 1); // expected-warning{{UNKNOWN}}\
+  expected-warning{{cast to 'char *' from smaller integer type 'int'}}
+  clang_analyzer_eval(n33.s2 == 0); //expected-warning{{UNKNOWN}}
+  return 0; // expected-warning{{Potential leak of memory pointed to by 'n33.s2'}}
+}
+
+// Test destination buffer being an unknown value.
+struct ww {
+  int s1[4];
+  char s2;
+};
+
+int f34(struct ww * w34, int n) {
+  w34->s2 = 3;
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(w34->s1 + n, input , 4);
+  clang_analyzer_eval(w34->s1[0] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(w34->s1[1] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(w34->s1[2] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(w34->s1[3] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(w34->s1[n] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(w34->s2 == 3); // expected-warning{{TRUE}}
+  return 0;
+}
+
+// Test dest buffer as an element region with a symbolic index and size parameter as a symbolic value.
+struct yy {
+  char s1[4];
+  char * s2;
+};
+
+int f35(int i, int n) {
+  struct yy y35 = {{1, 2, 3, 4}, 0};
+  y35.s2 = strdup("hello");
+  char input[] = {'a', 'b', 'c', 'd'};
+  memcpy(&(y35.s1[i]), input, n);
+  clang_analyzer_eval(y35.s1[0] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(y35.s1[1] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(y35.s1[2] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(y35.s1[3] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(y35.s1[i] == 0); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(y35.s2 == 0); // expected-warning{{UNKNOWN}}
+  return 0; // expected-warning{{Potential leak of memory pointed to by 'y35.s2'}}
+}
+
+// Test regions with negative offsets.
+struct zz {
+  char s1[4];
+  int s2;
+};
+
+int f36(struct zz * z36) {
+
+  char input[] = {'a', 'b', 'c', 'd'};
+  z36->s1[0] = 0;
+  z36->s1[1] = 1;
+  z36->s1[2] = 2;
+  z36->s1[3] = 3;
+  z36->s2 = 10;
+
+  z36 = z36 - 1; // Decrement by 8 bytes (struct zz is 8 bytes).
+
+  z36->s1[0] = 4;
+  z36->s1[1] = 5;
+  z36->s1[2] = 6;
+  z36->s1[3] = 7;
+  z36->s2 = 11;
+
+  memcpy(z36->s1, input, 4);
+
+  clang_analyzer_eval(z36->s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z36->s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z36->s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z36->s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z36->s2 == 11); // expected-warning{{TRUE}}
+
+  z36 = z36 + 1; // Increment back.
+
+  clang_analyzer_eval(z36->s1[0] == 0); // expected-warning{{TRUE}}
+  clang_analyzer_eval(z36->s1[1] == 1); // expected-warning{{TRUE}}
+  clang_analyzer_eval(z36->s1[2] == 2); // expected-warning{{TRUE}}
+  clang_analyzer_eval(z36->s1[3] == 3); // expected-warning{{TRUE}}
+  clang_analyzer_eval(z36->s2 == 10); // expected-warning{{TRUE}}
+
+  return 0;
+}
+
+int f37(struct zz * z37) {
+
+  char input[] = {'a', 'b', 'c', 'd'};
+  z37->s1[0] = 0;
+  z37->s1[1] = 1;
+  z37->s1[2] = 2;
+  z37->s1[3] = 3;
+  z37->s2 = 10;
+
+  z37 = (struct zz *)((char*)(z37) - 4); // Decrement by 4 bytes (struct zz is 8 bytes).
+
+  z37->s1[0] = 4;
+  z37->s1[1] = 5;
+  z37->s1[2] = 6;
+  z37->s1[3] = 7;
+  z37->s2 = 11;
+
+  memcpy(z37->s1, input, 4);
+
+  clang_analyzer_eval(z37->s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z37->s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z37->s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z37->s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z37->s2 == 11); // expected-warning{{TRUE}}
+
+  z37 = (struct zz *)((char*)(z37) + 4); // Increment back.
+
+  clang_analyzer_eval(z37->s1[0] == 11); // expected-warning{{TRUE}}
+  clang_analyzer_eval(z37->s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z37->s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z37->s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z37->s2 == 10); // expected-warning{{TRUE}}
+
+  return 0;
+}
+
+int f38(struct zz * z38) {
+
+  char input[] = {'a', 'b', 'c', 'd'};
+  z38->s1[0] = 0;
+  z38->s1[1] = 1;
+  z38->s1[2] = 2;
+  z38->s1[3] = 3;
+  z38->s2 = 10;
+
+  z38 = (struct zz *)((char*)(z38) - 2); // Decrement by 2 bytes (struct zz is 8 bytes).
+
+  z38->s1[0] = 4;
+  z38->s1[1] = 5;
+  z38->s1[2] = 6;
+  z38->s1[3] = 7;
+  z38->s2 = 11;
+
+  memcpy(z38->s1, input, 4);
+
+  clang_analyzer_eval(z38->s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z38->s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z38->s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z38->s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z38->s2 == 11); // expected-warning{{TRUE}}
+
+  z38 = (struct zz *)((char*)(z38) + 2); // Increment back.
+
+  clang_analyzer_eval(z38->s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z38->s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z38->s1[2] == 11); // expected-warning{{TRUE}}
+  clang_analyzer_eval(z38->s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z38->s2 == 10); // expected-warning{{UNKNOWN}}
+
+  return 0;
+}
+
+// Test negative offsets with a different structure layout.
+struct z0 {
+  int s2;
+  char s1[4];
+};
+
+int f39(struct z0 * d39) {
+
+  char input[] = {'a', 'b', 'c', 'd'};
+  d39->s1[0] = 0;
+  d39->s1[1] = 1;
+  d39->s1[2] = 2;
+  d39->s1[3] = 3;
+  d39->s2 = 10;
+
+  d39 = (struct z0 *)((char*)(d39) - 2); // Decrement by 2 bytes (struct z0 is 8 bytes).
+
+  d39->s1[0] = 4;
+  d39->s1[1] = 5;
+  d39->s1[2] = 6;
+  d39->s1[3] = 7;
+  d39->s2 = 11;
+
+  memcpy(d39->s1, input, 4);
+
+  clang_analyzer_eval(d39->s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(d39->s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(d39->s1[2] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(d39->s1[3] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(d39->s2 == 11); // expected-warning{{TRUE}}
+
+  d39 = (struct z0 *)((char*)(d39) + 2); // Increment back.
+
+  clang_analyzer_eval(d39->s1[0] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(d39->s1[1] == 1); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(d39->s1[2] == 2); // expected-warning{{TRUE}}
+  clang_analyzer_eval(d39->s1[3] == 3); // expected-warning{{TRUE}}
+  // FIXME: d39->s2 should evaluate to at least UNKNOWN or FALSE,
+  // 'collectSubRegionBindings(...)' in RegionStore.cpp will need to
+  // handle a regions' upper boundary overflowing.
+  clang_analyzer_eval(d39->s2 == 10); // expected-warning{{TRUE}}
+
+  return 0;
+}
+