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      1 // SValBuilder.h - Construction of SVals from evaluating expressions -*- C++ -*-
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 //  This file defines SValBuilder, a class that defines the interface for
     11 //  "symbolical evaluators" which construct an SVal from an expression.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #ifndef LLVM_CLANG_GR_SVALBUILDER
     16 #define LLVM_CLANG_GR_SVALBUILDER
     17 
     18 #include "clang/AST/Expr.h"
     19 #include "clang/AST/ExprCXX.h"
     20 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
     21 #include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h"
     22 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
     23 
     24 namespace clang {
     25 
     26 namespace ento {
     27 
     28 class GRState;
     29 
     30 class SValBuilder {
     31 protected:
     32   ASTContext &Context;
     33 
     34   /// Manager of APSInt values.
     35   BasicValueFactory BasicVals;
     36 
     37   /// Manages the creation of symbols.
     38   SymbolManager SymMgr;
     39 
     40   /// Manages the creation of memory regions.
     41   MemRegionManager MemMgr;
     42 
     43   GRStateManager &StateMgr;
     44 
     45   /// The scalar type to use for array indices.
     46   const QualType ArrayIndexTy;
     47 
     48   /// The width of the scalar type used for array indices.
     49   const unsigned ArrayIndexWidth;
     50 
     51 public:
     52   // FIXME: Make these protected again once RegionStoreManager correctly
     53   // handles loads from different bound value types.
     54   virtual SVal evalCastFromNonLoc(NonLoc val, QualType castTy) = 0;
     55   virtual SVal evalCastFromLoc(Loc val, QualType castTy) = 0;
     56 
     57 public:
     58   SValBuilder(llvm::BumpPtrAllocator &alloc, ASTContext &context,
     59               GRStateManager &stateMgr)
     60     : Context(context), BasicVals(context, alloc),
     61       SymMgr(context, BasicVals, alloc),
     62       MemMgr(context, alloc),
     63       StateMgr(stateMgr),
     64       ArrayIndexTy(context.IntTy),
     65       ArrayIndexWidth(context.getTypeSize(ArrayIndexTy)) {}
     66 
     67   virtual ~SValBuilder() {}
     68 
     69   SVal evalCast(SVal val, QualType castTy, QualType originalType);
     70 
     71   virtual SVal evalMinus(NonLoc val) = 0;
     72 
     73   virtual SVal evalComplement(NonLoc val) = 0;
     74 
     75   virtual SVal evalBinOpNN(const GRState *state, BinaryOperator::Opcode op,
     76                            NonLoc lhs, NonLoc rhs, QualType resultTy) = 0;
     77 
     78   virtual SVal evalBinOpLL(const GRState *state, BinaryOperator::Opcode op,
     79                            Loc lhs, Loc rhs, QualType resultTy) = 0;
     80 
     81   virtual SVal evalBinOpLN(const GRState *state, BinaryOperator::Opcode op,
     82                            Loc lhs, NonLoc rhs, QualType resultTy) = 0;
     83 
     84   /// getKnownValue - evaluates a given SVal. If the SVal has only one possible
     85   ///  (integer) value, that value is returned. Otherwise, returns NULL.
     86   virtual const llvm::APSInt *getKnownValue(const GRState *state, SVal val) = 0;
     87 
     88   SVal evalBinOp(const GRState *state, BinaryOperator::Opcode op,
     89                  SVal lhs, SVal rhs, QualType type);
     90 
     91   DefinedOrUnknownSVal evalEQ(const GRState *state, DefinedOrUnknownSVal lhs,
     92                               DefinedOrUnknownSVal rhs);
     93 
     94   ASTContext &getContext() { return Context; }
     95   const ASTContext &getContext() const { return Context; }
     96 
     97   GRStateManager &getStateManager() { return StateMgr; }
     98 
     99   QualType getConditionType() const {
    100     return  getContext().IntTy;
    101   }
    102 
    103   QualType getArrayIndexType() const {
    104     return ArrayIndexTy;
    105   }
    106 
    107   BasicValueFactory &getBasicValueFactory() { return BasicVals; }
    108   const BasicValueFactory &getBasicValueFactory() const { return BasicVals; }
    109 
    110   SymbolManager &getSymbolManager() { return SymMgr; }
    111   const SymbolManager &getSymbolManager() const { return SymMgr; }
    112 
    113   MemRegionManager &getRegionManager() { return MemMgr; }
    114   const MemRegionManager &getRegionManager() const { return MemMgr; }
    115 
    116   // Forwarding methods to SymbolManager.
    117 
    118   const SymbolConjured* getConjuredSymbol(const Stmt* stmt, QualType type,
    119                                           unsigned visitCount,
    120                                           const void* symbolTag = 0) {
    121     return SymMgr.getConjuredSymbol(stmt, type, visitCount, symbolTag);
    122   }
    123 
    124   const SymbolConjured* getConjuredSymbol(const Expr* expr, unsigned visitCount,
    125                                           const void* symbolTag = 0) {
    126     return SymMgr.getConjuredSymbol(expr, visitCount, symbolTag);
    127   }
    128 
    129   /// makeZeroVal - Construct an SVal representing '0' for the specified type.
    130   DefinedOrUnknownSVal makeZeroVal(QualType type);
    131 
    132   /// getRegionValueSymbolVal - make a unique symbol for value of region.
    133   DefinedOrUnknownSVal getRegionValueSymbolVal(const TypedRegion *region);
    134 
    135   DefinedOrUnknownSVal getConjuredSymbolVal(const void *symbolTag,
    136                                             const Expr *expr, unsigned count);
    137   DefinedOrUnknownSVal getConjuredSymbolVal(const void *symbolTag,
    138                                             const Expr *expr, QualType type,
    139                                             unsigned count);
    140 
    141   DefinedOrUnknownSVal getDerivedRegionValueSymbolVal(
    142       SymbolRef parentSymbol, const TypedRegion *region);
    143 
    144   DefinedSVal getMetadataSymbolVal(
    145       const void *symbolTag, const MemRegion *region,
    146       const Expr *expr, QualType type, unsigned count);
    147 
    148   DefinedSVal getFunctionPointer(const FunctionDecl *func);
    149 
    150   DefinedSVal getBlockPointer(const BlockDecl *block, CanQualType locTy,
    151                               const LocationContext *locContext);
    152 
    153   NonLoc makeCompoundVal(QualType type, llvm::ImmutableList<SVal> vals) {
    154     return nonloc::CompoundVal(BasicVals.getCompoundValData(type, vals));
    155   }
    156 
    157   NonLoc makeLazyCompoundVal(const StoreRef &store, const TypedRegion *region) {
    158     return nonloc::LazyCompoundVal(
    159         BasicVals.getLazyCompoundValData(store, region));
    160   }
    161 
    162   NonLoc makeZeroArrayIndex() {
    163     return nonloc::ConcreteInt(BasicVals.getValue(0, ArrayIndexTy));
    164   }
    165 
    166   NonLoc makeArrayIndex(uint64_t idx) {
    167     return nonloc::ConcreteInt(BasicVals.getValue(idx, ArrayIndexTy));
    168   }
    169 
    170   SVal convertToArrayIndex(SVal val);
    171 
    172   nonloc::ConcreteInt makeIntVal(const IntegerLiteral* integer) {
    173     return nonloc::ConcreteInt(
    174         BasicVals.getValue(integer->getValue(),
    175                      integer->getType()->isUnsignedIntegerOrEnumerationType()));
    176   }
    177 
    178   nonloc::ConcreteInt makeBoolVal(const CXXBoolLiteralExpr *boolean) {
    179     return makeTruthVal(boolean->getValue());
    180   }
    181 
    182   nonloc::ConcreteInt makeIntVal(const llvm::APSInt& integer) {
    183     return nonloc::ConcreteInt(BasicVals.getValue(integer));
    184   }
    185 
    186   loc::ConcreteInt makeIntLocVal(const llvm::APSInt &integer) {
    187     return loc::ConcreteInt(BasicVals.getValue(integer));
    188   }
    189 
    190   NonLoc makeIntVal(const llvm::APInt& integer, bool isUnsigned) {
    191     return nonloc::ConcreteInt(BasicVals.getValue(integer, isUnsigned));
    192   }
    193 
    194   DefinedSVal makeIntVal(uint64_t integer, QualType type) {
    195     if (Loc::isLocType(type))
    196       return loc::ConcreteInt(BasicVals.getValue(integer, type));
    197 
    198     return nonloc::ConcreteInt(BasicVals.getValue(integer, type));
    199   }
    200 
    201   NonLoc makeIntVal(uint64_t integer, bool isUnsigned) {
    202     return nonloc::ConcreteInt(BasicVals.getIntValue(integer, isUnsigned));
    203   }
    204 
    205   NonLoc makeIntValWithPtrWidth(uint64_t integer, bool isUnsigned) {
    206     return nonloc::ConcreteInt(
    207         BasicVals.getIntWithPtrWidth(integer, isUnsigned));
    208   }
    209 
    210   NonLoc makeIntVal(uint64_t integer, unsigned bitWidth, bool isUnsigned) {
    211     return nonloc::ConcreteInt(
    212         BasicVals.getValue(integer, bitWidth, isUnsigned));
    213   }
    214 
    215   NonLoc makeLocAsInteger(Loc loc, unsigned bits) {
    216     return nonloc::LocAsInteger(BasicVals.getPersistentSValWithData(loc, bits));
    217   }
    218 
    219   NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
    220                     const llvm::APSInt& rhs, QualType type);
    221 
    222   NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
    223                     const SymExpr *rhs, QualType type);
    224 
    225   nonloc::ConcreteInt makeTruthVal(bool b, QualType type) {
    226     return nonloc::ConcreteInt(BasicVals.getTruthValue(b, type));
    227   }
    228 
    229   nonloc::ConcreteInt makeTruthVal(bool b) {
    230     return nonloc::ConcreteInt(BasicVals.getTruthValue(b));
    231   }
    232 
    233   Loc makeNull() {
    234     return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth());
    235   }
    236 
    237   Loc makeLoc(SymbolRef sym) {
    238     return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
    239   }
    240 
    241   Loc makeLoc(const MemRegion* region) {
    242     return loc::MemRegionVal(region);
    243   }
    244 
    245   Loc makeLoc(const AddrLabelExpr *expr) {
    246     return loc::GotoLabel(expr->getLabel());
    247   }
    248 
    249   Loc makeLoc(const llvm::APSInt& integer) {
    250     return loc::ConcreteInt(BasicVals.getValue(integer));
    251   }
    252 
    253 };
    254 
    255 SValBuilder* createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc,
    256                                      ASTContext &context,
    257                                      GRStateManager &stateMgr);
    258 
    259 } // end GR namespace
    260 
    261 } // end clang namespace
    262 
    263 #endif
    264