1 files changed, 310 insertions, 0 deletions
diff --git a/lib/StaticAnalyzer/Core/SValBuilder.cpp b/lib/StaticAnalyzer/Core/SValBuilder.cpp
new file mode 100644
index 000000000000..b0fd497e5719
--- /dev/null
+++ b/lib/StaticAnalyzer/Core/SValBuilder.cpp
@@ -0,0 +1,310 @@
+// SValBuilder.cpp - Basic class for all SValBuilder implementations -*- 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 SValBuilder, the base class for all (complete) SValBuilder
+//  implementations.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/GRState.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h"
+
+using namespace clang;
+using namespace ento;
+
+//===----------------------------------------------------------------------===//
+// Basic SVal creation.
+//===----------------------------------------------------------------------===//
+
+DefinedOrUnknownSVal SValBuilder::makeZeroVal(QualType T) {
+  if (Loc::isLocType(T))
+    return makeNull();
+
+  if (T->isIntegerType())
+    return makeIntVal(0, T);
+
+  // FIXME: Handle floats.
+  // FIXME: Handle structs.
+  return UnknownVal();
+}
+
+
+NonLoc SValBuilder::makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
+                                const llvm::APSInt& v, QualType T) {
+  // The Environment ensures we always get a persistent APSInt in
+  // BasicValueFactory, so we don't need to get the APSInt from
+  // BasicValueFactory again.
+  assert(!Loc::isLocType(T));
+  return nonloc::SymExprVal(SymMgr.getSymIntExpr(lhs, op, v, T));
+}
+
+NonLoc SValBuilder::makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
+                                const SymExpr *rhs, QualType T) {
+  assert(SymMgr.getType(lhs) == SymMgr.getType(rhs));
+  assert(!Loc::isLocType(T));
+  return nonloc::SymExprVal(SymMgr.getSymSymExpr(lhs, op, rhs, T));
+}
+
+
+SVal SValBuilder::convertToArrayIndex(SVal V) {
+  if (V.isUnknownOrUndef())
+    return V;
+
+  // Common case: we have an appropriately sized integer.
+  if (nonloc::ConcreteInt* CI = dyn_cast<nonloc::ConcreteInt>(&V)) {
+    const llvm::APSInt& I = CI->getValue();
+    if (I.getBitWidth() == ArrayIndexWidth && I.isSigned())
+      return V;
+  }
+
+  return evalCastNL(cast<NonLoc>(V), ArrayIndexTy);
+}
+
+DefinedOrUnknownSVal 
+SValBuilder::getRegionValueSymbolVal(const TypedRegion* R) {
+  QualType T = R->getValueType();
+
+  if (!SymbolManager::canSymbolicate(T))
+    return UnknownVal();
+
+  SymbolRef sym = SymMgr.getRegionValueSymbol(R);
+
+  if (Loc::isLocType(T))
+    return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
+
+  return nonloc::SymbolVal(sym);
+}
+
+DefinedOrUnknownSVal SValBuilder::getConjuredSymbolVal(const void *SymbolTag,
+                                                        const Expr *E,
+                                                        unsigned Count) {
+  QualType T = E->getType();
+
+  if (!SymbolManager::canSymbolicate(T))
+    return UnknownVal();
+
+  SymbolRef sym = SymMgr.getConjuredSymbol(E, Count, SymbolTag);
+
+  if (Loc::isLocType(T))
+    return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
+
+  return nonloc::SymbolVal(sym);
+}
+
+DefinedOrUnknownSVal SValBuilder::getConjuredSymbolVal(const void *SymbolTag,
+                                                        const Expr *E,
+                                                        QualType T,
+                                                        unsigned Count) {
+  
+  if (!SymbolManager::canSymbolicate(T))
+    return UnknownVal();
+
+  SymbolRef sym = SymMgr.getConjuredSymbol(E, T, Count, SymbolTag);
+
+  if (Loc::isLocType(T))
+    return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
+
+  return nonloc::SymbolVal(sym);
+}
+
+DefinedSVal SValBuilder::getMetadataSymbolVal(const void *SymbolTag,
+                                               const MemRegion *MR,
+                                               const Expr *E, QualType T,
+                                               unsigned Count) {
+  assert(SymbolManager::canSymbolicate(T) && "Invalid metadata symbol type");
+
+  SymbolRef sym = SymMgr.getMetadataSymbol(MR, E, T, Count, SymbolTag);
+
+  if (Loc::isLocType(T))
+    return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
+
+  return nonloc::SymbolVal(sym);
+}
+
+DefinedOrUnknownSVal
+SValBuilder::getDerivedRegionValueSymbolVal(SymbolRef parentSymbol,
+                                             const TypedRegion *R) {
+  QualType T = R->getValueType();
+
+  if (!SymbolManager::canSymbolicate(T))
+    return UnknownVal();
+
+  SymbolRef sym = SymMgr.getDerivedSymbol(parentSymbol, R);
+
+  if (Loc::isLocType(T))
+    return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
+
+  return nonloc::SymbolVal(sym);
+}
+
+DefinedSVal SValBuilder::getFunctionPointer(const FunctionDecl* FD) {
+  return loc::MemRegionVal(MemMgr.getFunctionTextRegion(FD));
+}
+
+DefinedSVal SValBuilder::getBlockPointer(const BlockDecl *D,
+                                          CanQualType locTy,
+                                          const LocationContext *LC) {
+  const BlockTextRegion *BC =
+    MemMgr.getBlockTextRegion(D, locTy, LC->getAnalysisContext());
+  const BlockDataRegion *BD = MemMgr.getBlockDataRegion(BC, LC);
+  return loc::MemRegionVal(BD);
+}
+
+//===----------------------------------------------------------------------===//
+
+SVal SValBuilder::evalBinOp(const GRState *ST, BinaryOperator::Opcode Op,
+                          SVal L, SVal R, QualType T) {
+
+  if (L.isUndef() || R.isUndef())
+    return UndefinedVal();
+
+  if (L.isUnknown() || R.isUnknown())
+    return UnknownVal();
+
+  if (isa<Loc>(L)) {
+    if (isa<Loc>(R))
+      return evalBinOpLL(ST, Op, cast<Loc>(L), cast<Loc>(R), T);
+
+    return evalBinOpLN(ST, Op, cast<Loc>(L), cast<NonLoc>(R), T);
+  }
+
+  if (isa<Loc>(R)) {
+    // Support pointer arithmetic where the addend is on the left
+    // and the pointer on the right.
+    assert(Op == BO_Add);
+
+    // Commute the operands.
+    return evalBinOpLN(ST, Op, cast<Loc>(R), cast<NonLoc>(L), T);
+  }
+
+  return evalBinOpNN(ST, Op, cast<NonLoc>(L), cast<NonLoc>(R), T);
+}
+
+DefinedOrUnknownSVal SValBuilder::evalEQ(const GRState *ST,
+                                       DefinedOrUnknownSVal L,
+                                       DefinedOrUnknownSVal R) {
+  return cast<DefinedOrUnknownSVal>(evalBinOp(ST, BO_EQ, L, R,
+                                              Context.IntTy));
+}
+
+// FIXME: should rewrite according to the cast kind.
+SVal SValBuilder::evalCast(SVal val, QualType castTy, QualType originalTy) {
+  if (val.isUnknownOrUndef() || castTy == originalTy)
+    return val;
+
+  // For const casts, just propagate the value.
+  if (!castTy->isVariableArrayType() && !originalTy->isVariableArrayType())
+    if (Context.hasSameUnqualifiedType(castTy, originalTy))
+      return val;
+
+  // Check for casts to real or complex numbers.  We don't handle these at all
+  // right now.
+  if (castTy->isFloatingType() || castTy->isAnyComplexType())
+    return UnknownVal();
+  
+  // Check for casts from integers to integers.
+  if (castTy->isIntegerType() && originalTy->isIntegerType())
+    return evalCastNL(cast<NonLoc>(val), castTy);
+
+  // Check for casts from pointers to integers.
+  if (castTy->isIntegerType() && Loc::isLocType(originalTy))
+    return evalCastL(cast<Loc>(val), castTy);
+
+  // Check for casts from integers to pointers.
+  if (Loc::isLocType(castTy) && originalTy->isIntegerType()) {
+    if (nonloc::LocAsInteger *LV = dyn_cast<nonloc::LocAsInteger>(&val)) {
+      if (const MemRegion *R = LV->getLoc().getAsRegion()) {
+        StoreManager &storeMgr = StateMgr.getStoreManager();
+        R = storeMgr.castRegion(R, castTy);
+        return R ? SVal(loc::MemRegionVal(R)) : UnknownVal();
+      }
+      return LV->getLoc();
+    }
+    goto DispatchCast;
+  }
+
+  // Just pass through function and block pointers.
+  if (originalTy->isBlockPointerType() || originalTy->isFunctionPointerType()) {
+    assert(Loc::isLocType(castTy));
+    return val;
+  }
+
+  // Check for casts from array type to another type.
+  if (originalTy->isArrayType()) {
+    // We will always decay to a pointer.
+    val = StateMgr.ArrayToPointer(cast<Loc>(val));
+
+    // Are we casting from an array to a pointer?  If so just pass on
+    // the decayed value.
+    if (castTy->isPointerType())
+      return val;
+
+    // Are we casting from an array to an integer?  If so, cast the decayed
+    // pointer value to an integer.
+    assert(castTy->isIntegerType());
+
+    // FIXME: Keep these here for now in case we decide soon that we
+    // need the original decayed type.
+    //    QualType elemTy = cast<ArrayType>(originalTy)->getElementType();
+    //    QualType pointerTy = C.getPointerType(elemTy);
+    return evalCastL(cast<Loc>(val), castTy);
+  }
+
+  // Check for casts from a region to a specific type.
+  if (const MemRegion *R = val.getAsRegion()) {
+    // FIXME: We should handle the case where we strip off view layers to get
+    //  to a desugared type.
+
+    if (!Loc::isLocType(castTy)) {
+      // FIXME: There can be gross cases where one casts the result of a function
+      // (that returns a pointer) to some other value that happens to fit
+      // within that pointer value.  We currently have no good way to
+      // model such operations.  When this happens, the underlying operation
+      // is that the caller is reasoning about bits.  Conceptually we are
+      // layering a "view" of a location on top of those bits.  Perhaps
+      // we need to be more lazy about mutual possible views, even on an
+      // SVal?  This may be necessary for bit-level reasoning as well.
+      return UnknownVal();
+    }
+
+    // We get a symbolic function pointer for a dereference of a function
+    // pointer, but it is of function type. Example:
+
+    //  struct FPRec {
+    //    void (*my_func)(int * x);
+    //  };
+    //
+    //  int bar(int x);
+    //
+    //  int f1_a(struct FPRec* foo) {
+    //    int x;
+    //    (*foo->my_func)(&x);
+    //    return bar(x)+1; // no-warning
+    //  }
+
+    assert(Loc::isLocType(originalTy) || originalTy->isFunctionType() ||
+           originalTy->isBlockPointerType() || castTy->isReferenceType());
+
+    StoreManager &storeMgr = StateMgr.getStoreManager();
+
+    // Delegate to store manager to get the result of casting a region to a
+    // different type.  If the MemRegion* returned is NULL, this expression
+    // Evaluates to UnknownVal.
+    R = storeMgr.castRegion(R, castTy);
+    return R ? SVal(loc::MemRegionVal(R)) : UnknownVal();
+  }
+
+DispatchCast:
+  // All other cases.
+  return isa<Loc>(val) ? evalCastL(cast<Loc>(val), castTy)
+                       : evalCastNL(cast<NonLoc>(val), castTy);
+}