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

1 files changed, 362 insertions, 0 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/Store.cpp b/clang/lib/StaticAnalyzer/Core/Store.cpp
new file mode 100644
index 0000000..11748ae
--- /dev/null
+++ b/clang/lib/StaticAnalyzer/Core/Store.cpp
@@ -0,0 +1,362 @@
+//== Store.cpp - Interface for maps from Locations to Values ----*- C++ -*--==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defined the types Store and StoreManager.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/StaticAnalyzer/Core/PathSensitive/Store.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
+#include "clang/AST/CharUnits.h"
+#include "clang/AST/DeclObjC.h"
+
+using namespace clang;
+using namespace ento;
+
+StoreManager::StoreManager(ProgramStateManager &stateMgr)
+  : svalBuilder(stateMgr.getSValBuilder()), StateMgr(stateMgr),
+    MRMgr(svalBuilder.getRegionManager()), Ctx(stateMgr.getContext()) {}
+
+StoreRef StoreManager::enterStackFrame(ProgramStateRef state,
+                                       const LocationContext *callerCtx,
+                                       const StackFrameContext *calleeCtx) {
+  return StoreRef(state->getStore(), *this);
+}
+
+const MemRegion *StoreManager::MakeElementRegion(const MemRegion *Base,
+                                              QualType EleTy, uint64_t index) {
+  NonLoc idx = svalBuilder.makeArrayIndex(index);
+  return MRMgr.getElementRegion(EleTy, idx, Base, svalBuilder.getContext());
+}
+
+// FIXME: Merge with the implementation of the same method in MemRegion.cpp
+static bool IsCompleteType(ASTContext &Ctx, QualType Ty) {
+  if (const RecordType *RT = Ty->getAs<RecordType>()) {
+    const RecordDecl *D = RT->getDecl();
+    if (!D->getDefinition())
+      return false;
+  }
+
+  return true;
+}
+
+StoreRef StoreManager::BindDefault(Store store, const MemRegion *R, SVal V) {
+  return StoreRef(store, *this);
+}
+
+const ElementRegion *StoreManager::GetElementZeroRegion(const MemRegion *R, 
+                                                        QualType T) {
+  NonLoc idx = svalBuilder.makeZeroArrayIndex();
+  assert(!T.isNull());
+  return MRMgr.getElementRegion(T, idx, R, Ctx);
+}
+
+const MemRegion *StoreManager::castRegion(const MemRegion *R, QualType CastToTy) {
+
+  ASTContext &Ctx = StateMgr.getContext();
+
+  // Handle casts to Objective-C objects.
+  if (CastToTy->isObjCObjectPointerType())
+    return R->StripCasts();
+
+  if (CastToTy->isBlockPointerType()) {
+    // FIXME: We may need different solutions, depending on the symbol
+    // involved.  Blocks can be casted to/from 'id', as they can be treated
+    // as Objective-C objects.  This could possibly be handled by enhancing
+    // our reasoning of downcasts of symbolic objects.
+    if (isa<CodeTextRegion>(R) || isa<SymbolicRegion>(R))
+      return R;
+
+    // We don't know what to make of it.  Return a NULL region, which
+    // will be interpretted as UnknownVal.
+    return NULL;
+  }
+
+  // Now assume we are casting from pointer to pointer. Other cases should
+  // already be handled.
+  QualType PointeeTy = CastToTy->getPointeeType();
+  QualType CanonPointeeTy = Ctx.getCanonicalType(PointeeTy);
+
+  // Handle casts to void*.  We just pass the region through.
+  if (CanonPointeeTy.getLocalUnqualifiedType() == Ctx.VoidTy)
+    return R;
+
+  // Handle casts from compatible types.
+  if (R->isBoundable())
+    if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) {
+      QualType ObjTy = Ctx.getCanonicalType(TR->getValueType());
+      if (CanonPointeeTy == ObjTy)
+        return R;
+    }
+
+  // Process region cast according to the kind of the region being cast.
+  switch (R->getKind()) {
+    case MemRegion::CXXThisRegionKind:
+    case MemRegion::GenericMemSpaceRegionKind:
+    case MemRegion::StackLocalsSpaceRegionKind:
+    case MemRegion::StackArgumentsSpaceRegionKind:
+    case MemRegion::HeapSpaceRegionKind:
+    case MemRegion::UnknownSpaceRegionKind:
+    case MemRegion::StaticGlobalSpaceRegionKind:
+    case MemRegion::GlobalInternalSpaceRegionKind:
+    case MemRegion::GlobalSystemSpaceRegionKind:
+    case MemRegion::GlobalImmutableSpaceRegionKind: {
+      llvm_unreachable("Invalid region cast");
+    }
+
+    case MemRegion::FunctionTextRegionKind:
+    case MemRegion::BlockTextRegionKind:
+    case MemRegion::BlockDataRegionKind:
+    case MemRegion::StringRegionKind:
+      // FIXME: Need to handle arbitrary downcasts.
+    case MemRegion::SymbolicRegionKind:
+    case MemRegion::AllocaRegionKind:
+    case MemRegion::CompoundLiteralRegionKind:
+    case MemRegion::FieldRegionKind:
+    case MemRegion::ObjCIvarRegionKind:
+    case MemRegion::ObjCStringRegionKind:
+    case MemRegion::VarRegionKind:
+    case MemRegion::CXXTempObjectRegionKind:
+    case MemRegion::CXXBaseObjectRegionKind:
+      return MakeElementRegion(R, PointeeTy);
+
+    case MemRegion::ElementRegionKind: {
+      // If we are casting from an ElementRegion to another type, the
+      // algorithm is as follows:
+      //
+      // (1) Compute the "raw offset" of the ElementRegion from the
+      //     base region.  This is done by calling 'getAsRawOffset()'.
+      //
+      // (2a) If we get a 'RegionRawOffset' after calling
+      //      'getAsRawOffset()', determine if the absolute offset
+      //      can be exactly divided into chunks of the size of the
+      //      casted-pointee type.  If so, create a new ElementRegion with
+      //      the pointee-cast type as the new ElementType and the index
+      //      being the offset divded by the chunk size.  If not, create
+      //      a new ElementRegion at offset 0 off the raw offset region.
+      //
+      // (2b) If we don't a get a 'RegionRawOffset' after calling
+      //      'getAsRawOffset()', it means that we are at offset 0.
+      //
+      // FIXME: Handle symbolic raw offsets.
+
+      const ElementRegion *elementR = cast<ElementRegion>(R);
+      const RegionRawOffset &rawOff = elementR->getAsArrayOffset();
+      const MemRegion *baseR = rawOff.getRegion();
+
+      // If we cannot compute a raw offset, throw up our hands and return
+      // a NULL MemRegion*.
+      if (!baseR)
+        return NULL;
+
+      CharUnits off = rawOff.getOffset();
+
+      if (off.isZero()) {
+        // Edge case: we are at 0 bytes off the beginning of baseR.  We
+        // check to see if type we are casting to is the same as the base
+        // region.  If so, just return the base region.
+        if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(baseR)) {
+          QualType ObjTy = Ctx.getCanonicalType(TR->getValueType());
+          QualType CanonPointeeTy = Ctx.getCanonicalType(PointeeTy);
+          if (CanonPointeeTy == ObjTy)
+            return baseR;
+        }
+
+        // Otherwise, create a new ElementRegion at offset 0.
+        return MakeElementRegion(baseR, PointeeTy);
+      }
+
+      // We have a non-zero offset from the base region.  We want to determine
+      // if the offset can be evenly divided by sizeof(PointeeTy).  If so,
+      // we create an ElementRegion whose index is that value.  Otherwise, we
+      // create two ElementRegions, one that reflects a raw offset and the other
+      // that reflects the cast.
+
+      // Compute the index for the new ElementRegion.
+      int64_t newIndex = 0;
+      const MemRegion *newSuperR = 0;
+
+      // We can only compute sizeof(PointeeTy) if it is a complete type.
+      if (IsCompleteType(Ctx, PointeeTy)) {
+        // Compute the size in **bytes**.
+        CharUnits pointeeTySize = Ctx.getTypeSizeInChars(PointeeTy);
+        if (!pointeeTySize.isZero()) {
+          // Is the offset a multiple of the size?  If so, we can layer the
+          // ElementRegion (with elementType == PointeeTy) directly on top of
+          // the base region.
+          if (off % pointeeTySize == 0) {
+            newIndex = off / pointeeTySize;
+            newSuperR = baseR;
+          }
+        }
+      }
+
+      if (!newSuperR) {
+        // Create an intermediate ElementRegion to represent the raw byte.
+        // This will be the super region of the final ElementRegion.
+        newSuperR = MakeElementRegion(baseR, Ctx.CharTy, off.getQuantity());
+      }
+
+      return MakeElementRegion(newSuperR, PointeeTy, newIndex);
+    }
+  }
+
+  llvm_unreachable("unreachable");
+}
+
+
+/// CastRetrievedVal - Used by subclasses of StoreManager to implement
+///  implicit casts that arise from loads from regions that are reinterpreted
+///  as another region.
+SVal StoreManager::CastRetrievedVal(SVal V, const TypedValueRegion *R,
+                                    QualType castTy, bool performTestOnly) {
+  
+  if (castTy.isNull() || V.isUnknownOrUndef())
+    return V;
+  
+  ASTContext &Ctx = svalBuilder.getContext();
+
+  if (performTestOnly) {  
+    // Automatically translate references to pointers.
+    QualType T = R->getValueType();
+    if (const ReferenceType *RT = T->getAs<ReferenceType>())
+      T = Ctx.getPointerType(RT->getPointeeType());
+    
+    assert(svalBuilder.getContext().hasSameUnqualifiedType(castTy, T));
+    return V;
+  }
+  
+  return svalBuilder.dispatchCast(V, castTy);
+}
+
+SVal StoreManager::getLValueFieldOrIvar(const Decl *D, SVal Base) {
+  if (Base.isUnknownOrUndef())
+    return Base;
+
+  Loc BaseL = cast<Loc>(Base);
+  const MemRegion* BaseR = 0;
+
+  switch (BaseL.getSubKind()) {
+  case loc::MemRegionKind:
+    BaseR = cast<loc::MemRegionVal>(BaseL).getRegion();
+    break;
+
+  case loc::GotoLabelKind:
+    // These are anormal cases. Flag an undefined value.
+    return UndefinedVal();
+
+  case loc::ConcreteIntKind:
+    // While these seem funny, this can happen through casts.
+    // FIXME: What we should return is the field offset.  For example,
+    //  add the field offset to the integer value.  That way funny things
+    //  like this work properly:  &(((struct foo *) 0xa)->f)
+    return Base;
+
+  default:
+    llvm_unreachable("Unhandled Base.");
+  }
+
+  // NOTE: We must have this check first because ObjCIvarDecl is a subclass
+  // of FieldDecl.
+  if (const ObjCIvarDecl *ID = dyn_cast<ObjCIvarDecl>(D))
+    return loc::MemRegionVal(MRMgr.getObjCIvarRegion(ID, BaseR));
+
+  return loc::MemRegionVal(MRMgr.getFieldRegion(cast<FieldDecl>(D), BaseR));
+}
+
+SVal StoreManager::getLValueIvar(const ObjCIvarDecl *decl, SVal base) {
+  return getLValueFieldOrIvar(decl, base);
+}
+
+SVal StoreManager::getLValueElement(QualType elementType, NonLoc Offset, 
+                                    SVal Base) {
+
+  // If the base is an unknown or undefined value, just return it back.
+  // FIXME: For absolute pointer addresses, we just return that value back as
+  //  well, although in reality we should return the offset added to that
+  //  value.
+  if (Base.isUnknownOrUndef() || isa<loc::ConcreteInt>(Base))
+    return Base;
+
+  const MemRegion* BaseRegion = cast<loc::MemRegionVal>(Base).getRegion();
+
+  // Pointer of any type can be cast and used as array base.
+  const ElementRegion *ElemR = dyn_cast<ElementRegion>(BaseRegion);
+
+  // Convert the offset to the appropriate size and signedness.
+  Offset = cast<NonLoc>(svalBuilder.convertToArrayIndex(Offset));
+
+  if (!ElemR) {
+    //
+    // If the base region is not an ElementRegion, create one.
+    // This can happen in the following example:
+    //
+    //   char *p = __builtin_alloc(10);
+    //   p[1] = 8;
+    //
+    //  Observe that 'p' binds to an AllocaRegion.
+    //
+    return loc::MemRegionVal(MRMgr.getElementRegion(elementType, Offset,
+                                                    BaseRegion, Ctx));
+  }
+
+  SVal BaseIdx = ElemR->getIndex();
+
+  if (!isa<nonloc::ConcreteInt>(BaseIdx))
+    return UnknownVal();
+
+  const llvm::APSInt& BaseIdxI = cast<nonloc::ConcreteInt>(BaseIdx).getValue();
+
+  // Only allow non-integer offsets if the base region has no offset itself.
+  // FIXME: This is a somewhat arbitrary restriction. We should be using
+  // SValBuilder here to add the two offsets without checking their types.
+  if (!isa<nonloc::ConcreteInt>(Offset)) {
+    if (isa<ElementRegion>(BaseRegion->StripCasts()))
+      return UnknownVal();
+
+    return loc::MemRegionVal(MRMgr.getElementRegion(elementType, Offset,
+                                                    ElemR->getSuperRegion(),
+                                                    Ctx));
+  }
+
+  const llvm::APSInt& OffI = cast<nonloc::ConcreteInt>(Offset).getValue();
+  assert(BaseIdxI.isSigned());
+
+  // Compute the new index.
+  nonloc::ConcreteInt NewIdx(svalBuilder.getBasicValueFactory().getValue(BaseIdxI +
+                                                                    OffI));
+
+  // Construct the new ElementRegion.
+  const MemRegion *ArrayR = ElemR->getSuperRegion();
+  return loc::MemRegionVal(MRMgr.getElementRegion(elementType, NewIdx, ArrayR,
+                                                  Ctx));
+}
+
+StoreManager::BindingsHandler::~BindingsHandler() {}
+
+bool StoreManager::FindUniqueBinding::HandleBinding(StoreManager& SMgr,
+                                                    Store store,
+                                                    const MemRegion* R,
+                                                    SVal val) {
+  SymbolRef SymV = val.getAsLocSymbol();
+  if (!SymV || SymV != Sym)
+    return true;
+
+  if (Binding) {
+    First = false;
+    return false;
+  }
+  else
+    Binding = R;
+
+  return true;
+}
+
+void SubRegionMap::anchor() { }
+void SubRegionMap::Visitor::anchor() { }