SValBuilder.h revision 91ab900a939e95d965e18299b66928fdbe2aa38d 
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/ASTContext.h"
19#include "clang/AST/Expr.h"
20#include "clang/AST/ExprCXX.h"
21#include "clang/AST/ExprObjC.h"
22#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
23#include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h"
24#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
25
26namespace clang {
27
28class CXXBoolLiteralExpr;
29
30namespace ento {
31
32class SValBuilder {
33  virtual void anchor();
34protected:
35  ASTContext &Context;
36
37  /// Manager of APSInt values.
38  BasicValueFactory BasicVals;
39
40  /// Manages the creation of symbols.
41  SymbolManager SymMgr;
42
43  /// Manages the creation of memory regions.
44  MemRegionManager MemMgr;
45
46  ProgramStateManager &StateMgr;
47
48  /// The scalar type to use for array indices.
49  const QualType ArrayIndexTy;
50
51  /// The width of the scalar type used for array indices.
52  const unsigned ArrayIndexWidth;
53
54  virtual SVal evalCastFromNonLoc(NonLoc val, QualType castTy) = 0;
55  virtual SVal evalCastFromLoc(Loc val, QualType castTy) = 0;
56
57public:
58  // FIXME: Make these protected again once RegionStoreManager correctly
59  // handles loads from different bound value types.
60  virtual SVal dispatchCast(SVal val, QualType castTy) = 0;
61
62public:
63  SValBuilder(llvm::BumpPtrAllocator &alloc, ASTContext &context,
64              ProgramStateManager &stateMgr)
65    : Context(context), BasicVals(context, alloc),
66      SymMgr(context, BasicVals, alloc),
67      MemMgr(context, alloc),
68      StateMgr(stateMgr),
69      ArrayIndexTy(context.IntTy),
70      ArrayIndexWidth(context.getTypeSize(ArrayIndexTy)) {}
71
72  virtual ~SValBuilder() {}
73
74  bool haveSameType(const SymExpr *Sym1, const SymExpr *Sym2) {
75    return haveSameType(Sym1->getType(Context), Sym2->getType(Context));
76  }
77
78  bool haveSameType(QualType Ty1, QualType Ty2) {
79    // FIXME: Remove the second disjunct when we support symbolic
80    // truncation/extension.
81    return (Context.getCanonicalType(Ty1) == Context.getCanonicalType(Ty2) ||
82            (Ty1->isIntegerType() && Ty2->isIntegerType()));
83  }
84
85  SVal evalCast(SVal val, QualType castTy, QualType originalType);
86
87  virtual SVal evalMinus(NonLoc val) = 0;
88
89  virtual SVal evalComplement(NonLoc val) = 0;
90
91  /// Create a new value which represents a binary expression with two non
92  /// location operands.
93  virtual SVal evalBinOpNN(ProgramStateRef state, BinaryOperator::Opcode op,
94                           NonLoc lhs, NonLoc rhs, QualType resultTy) = 0;
95
96  /// Create a new value which represents a binary expression with two memory
97  /// location operands.
98  virtual SVal evalBinOpLL(ProgramStateRef state, BinaryOperator::Opcode op,
99                           Loc lhs, Loc rhs, QualType resultTy) = 0;
100
101  /// Create a new value which represents a binary expression with a memory
102  /// location and non location operands. For example, this would be used to
103  /// evaluate a pointer arithmetic operation.
104  virtual SVal evalBinOpLN(ProgramStateRef state, BinaryOperator::Opcode op,
105                           Loc lhs, NonLoc rhs, QualType resultTy) = 0;
106
107  /// Evaluates a given SVal. If the SVal has only one possible (integer) value,
108  /// that value is returned. Otherwise, returns NULL.
109  virtual const llvm::APSInt *getKnownValue(ProgramStateRef state, SVal val) = 0;
110
111  /// Constructs a symbolic expression for two non-location values.
112  SVal makeSymExprValNN(ProgramStateRef state, BinaryOperator::Opcode op,
113                      NonLoc lhs, NonLoc rhs, QualType resultTy);
114
115  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
116                 SVal lhs, SVal rhs, QualType type);
117
118  DefinedOrUnknownSVal evalEQ(ProgramStateRef state, DefinedOrUnknownSVal lhs,
119                              DefinedOrUnknownSVal rhs);
120
121  ASTContext &getContext() { return Context; }
122  const ASTContext &getContext() const { return Context; }
123
124  ProgramStateManager &getStateManager() { return StateMgr; }
125
126  QualType getConditionType() const {
127    return  getContext().IntTy;
128  }
129
130  QualType getArrayIndexType() const {
131    return ArrayIndexTy;
132  }
133
134  BasicValueFactory &getBasicValueFactory() { return BasicVals; }
135  const BasicValueFactory &getBasicValueFactory() const { return BasicVals; }
136
137  SymbolManager &getSymbolManager() { return SymMgr; }
138  const SymbolManager &getSymbolManager() const { return SymMgr; }
139
140  MemRegionManager &getRegionManager() { return MemMgr; }
141  const MemRegionManager &getRegionManager() const { return MemMgr; }
142
143  // Forwarding methods to SymbolManager.
144
145  const SymbolConjured* conjureSymbol(const Stmt *stmt,
146                                      const LocationContext *LCtx,
147                                      QualType type,
148                                      unsigned visitCount,
149                                      const void *symbolTag = 0) {
150    return SymMgr.conjureSymbol(stmt, LCtx, type, visitCount, symbolTag);
151  }
152
153  const SymbolConjured* conjureSymbol(const Expr *expr,
154                                      const LocationContext *LCtx,
155                                      unsigned visitCount,
156                                      const void *symbolTag = 0) {
157    return SymMgr.conjureSymbol(expr, LCtx, visitCount, symbolTag);
158  }
159
160  /// Construct an SVal representing '0' for the specified type.
161  DefinedOrUnknownSVal makeZeroVal(QualType type);
162
163  /// Make a unique symbol for value of region.
164  DefinedOrUnknownSVal getRegionValueSymbolVal(const TypedValueRegion *region);
165
166  /// \brief Create a new symbol with a unique 'name'.
167  ///
168  /// We resort to conjured symbols when we cannot construct a derived symbol.
169  /// The advantage of symbols derived/built from other symbols is that we
170  /// preserve the relation between related(or even equivalent) expressions, so
171  /// conjured symbols should be used sparingly.
172  DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag,
173                                        const Expr *expr,
174                                        const LocationContext *LCtx,
175                                        unsigned count);
176  DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag,
177                                        const Expr *expr,
178                                        const LocationContext *LCtx,
179                                        QualType type,
180                                        unsigned count);
181
182  DefinedOrUnknownSVal conjureSymbolVal(const Stmt *stmt,
183                                        const LocationContext *LCtx,
184                                        QualType type,
185                                        unsigned visitCount);
186  /// \brief Conjure a symbol representing heap allocated memory region.
187  ///
188  /// Note, the expression should represent a location.
189  DefinedOrUnknownSVal getConjuredHeapSymbolVal(const Expr *E,
190                                                const LocationContext *LCtx,
191                                                unsigned Count);
192
193  DefinedOrUnknownSVal getDerivedRegionValueSymbolVal(
194      SymbolRef parentSymbol, const TypedValueRegion *region);
195
196  DefinedSVal getMetadataSymbolVal(
197      const void *symbolTag, const MemRegion *region,
198      const Expr *expr, QualType type, unsigned count);
199
200  DefinedSVal getFunctionPointer(const FunctionDecl *func);
201
202  DefinedSVal getBlockPointer(const BlockDecl *block, CanQualType locTy,
203                              const LocationContext *locContext);
204
205  NonLoc makeCompoundVal(QualType type, llvm::ImmutableList<SVal> vals) {
206    return nonloc::CompoundVal(BasicVals.getCompoundValData(type, vals));
207  }
208
209  NonLoc makeLazyCompoundVal(const StoreRef &store,
210                             const TypedValueRegion *region) {
211    return nonloc::LazyCompoundVal(
212        BasicVals.getLazyCompoundValData(store, region));
213  }
214
215  NonLoc makeZeroArrayIndex() {
216    return nonloc::ConcreteInt(BasicVals.getValue(0, ArrayIndexTy));
217  }
218
219  NonLoc makeArrayIndex(uint64_t idx) {
220    return nonloc::ConcreteInt(BasicVals.getValue(idx, ArrayIndexTy));
221  }
222
223  SVal convertToArrayIndex(SVal val);
224
225  nonloc::ConcreteInt makeIntVal(const IntegerLiteral* integer) {
226    return nonloc::ConcreteInt(
227        BasicVals.getValue(integer->getValue(),
228                     integer->getType()->isUnsignedIntegerOrEnumerationType()));
229  }
230
231  nonloc::ConcreteInt makeBoolVal(const ObjCBoolLiteralExpr *boolean) {
232    return makeTruthVal(boolean->getValue(), boolean->getType());
233  }
234
235  nonloc::ConcreteInt makeBoolVal(const CXXBoolLiteralExpr *boolean);
236
237  nonloc::ConcreteInt makeIntVal(const llvm::APSInt& integer) {
238    return nonloc::ConcreteInt(BasicVals.getValue(integer));
239  }
240
241  loc::ConcreteInt makeIntLocVal(const llvm::APSInt &integer) {
242    return loc::ConcreteInt(BasicVals.getValue(integer));
243  }
244
245  NonLoc makeIntVal(const llvm::APInt& integer, bool isUnsigned) {
246    return nonloc::ConcreteInt(BasicVals.getValue(integer, isUnsigned));
247  }
248
249  DefinedSVal makeIntVal(uint64_t integer, QualType type) {
250    if (Loc::isLocType(type))
251      return loc::ConcreteInt(BasicVals.getValue(integer, type));
252
253    return nonloc::ConcreteInt(BasicVals.getValue(integer, type));
254  }
255
256  NonLoc makeIntVal(uint64_t integer, bool isUnsigned) {
257    return nonloc::ConcreteInt(BasicVals.getIntValue(integer, isUnsigned));
258  }
259
260  NonLoc makeIntValWithPtrWidth(uint64_t integer, bool isUnsigned) {
261    return nonloc::ConcreteInt(
262        BasicVals.getIntWithPtrWidth(integer, isUnsigned));
263  }
264
265  NonLoc makeLocAsInteger(Loc loc, unsigned bits) {
266    return nonloc::LocAsInteger(BasicVals.getPersistentSValWithData(loc, bits));
267  }
268
269  NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
270                    const llvm::APSInt& rhs, QualType type);
271
272  NonLoc makeNonLoc(const llvm::APSInt& rhs, BinaryOperator::Opcode op,
273                    const SymExpr *lhs, QualType type);
274
275  NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
276                    const SymExpr *rhs, QualType type);
277
278  /// \brief Create a NonLoc value for cast.
279  NonLoc makeNonLoc(const SymExpr *operand, QualType fromTy, QualType toTy);
280
281  nonloc::ConcreteInt makeTruthVal(bool b, QualType type) {
282    return nonloc::ConcreteInt(BasicVals.getTruthValue(b, type));
283  }
284
285  nonloc::ConcreteInt makeTruthVal(bool b) {
286    return nonloc::ConcreteInt(BasicVals.getTruthValue(b));
287  }
288
289  Loc makeNull() {
290    return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth());
291  }
292
293  Loc makeLoc(SymbolRef sym) {
294    return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
295  }
296
297  Loc makeLoc(const MemRegion* region) {
298    return loc::MemRegionVal(region);
299  }
300
301  Loc makeLoc(const AddrLabelExpr *expr) {
302    return loc::GotoLabel(expr->getLabel());
303  }
304
305  Loc makeLoc(const llvm::APSInt& integer) {
306    return loc::ConcreteInt(BasicVals.getValue(integer));
307  }
308
309  /// Return a memory region for the 'this' object reference.
310  loc::MemRegionVal getCXXThis(const CXXMethodDecl *D,
311                               const StackFrameContext *SFC);
312
313  /// Return a memory region for the 'this' object reference.
314  loc::MemRegionVal getCXXThis(const CXXRecordDecl *D,
315                               const StackFrameContext *SFC);
316};
317
318SValBuilder* createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc,
319                                     ASTContext &context,
320                                     ProgramStateManager &stateMgr);
321
322} // end GR namespace
323
324} // end clang namespace
325
326#endif
327