SValBuilder.h revision e2b1246a24e8babf2f58c93713fba16b8edb8e2d 
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/ExprObjC.h"
21#include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h"
22#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
23#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
24
25namespace clang {
26
27class CXXBoolLiteralExpr;
28
29namespace ento {
30
31class SValBuilder {
32  virtual void anchor();
33protected:
34  ASTContext &Context;
35
36  /// Manager of APSInt values.
37  BasicValueFactory BasicVals;
38
39  /// Manages the creation of symbols.
40  SymbolManager SymMgr;
41
42  /// Manages the creation of memory regions.
43  MemRegionManager MemMgr;
44
45  ProgramStateManager &StateMgr;
46
47  /// The scalar type to use for array indices.
48  const QualType ArrayIndexTy;
49
50  /// The width of the scalar type used for array indices.
51  const unsigned ArrayIndexWidth;
52
53  virtual SVal evalCastFromNonLoc(NonLoc val, QualType castTy) = 0;
54  virtual SVal evalCastFromLoc(Loc val, QualType castTy) = 0;
55
56public:
57  // FIXME: Make these protected again once RegionStoreManager correctly
58  // handles loads from different bound value types.
59  virtual SVal dispatchCast(SVal val, QualType castTy) = 0;
60
61public:
62  SValBuilder(llvm::BumpPtrAllocator &alloc, ASTContext &context,
63              ProgramStateManager &stateMgr)
64    : Context(context), BasicVals(context, alloc),
65      SymMgr(context, BasicVals, alloc),
66      MemMgr(context, alloc),
67      StateMgr(stateMgr),
68      ArrayIndexTy(context.IntTy),
69      ArrayIndexWidth(context.getTypeSize(ArrayIndexTy)) {}
70
71  virtual ~SValBuilder() {}
72
73  bool haveSameType(const SymExpr *Sym1, const SymExpr *Sym2) {
74    return haveSameType(Sym1->getType(), Sym2->getType());
75  }
76
77  bool haveSameType(QualType Ty1, QualType Ty2) {
78    // FIXME: Remove the second disjunct when we support symbolic
79    // truncation/extension.
80    return (Context.getCanonicalType(Ty1) == Context.getCanonicalType(Ty2) ||
81            (Ty1->isIntegralOrEnumerationType() &&
82             Ty2->isIntegralOrEnumerationType()));
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 Context.getLangOpts().CPlusPlus ? Context.BoolTy : Context.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  /// Returns the value of \p E, if it can be determined in a non-path-sensitive
206  /// manner.
207  ///
208  /// If \p E is not a constant or cannot be modeled, returns \c None.
209  ///
210  /// Note that this function always treats \p E as a prvalue. Callers should
211  /// check to see if \p E is a glvalue and modify their behavior accordingly.
212  Optional<SVal> getConstantVal(const Expr *E);
213
214  NonLoc makeCompoundVal(QualType type, llvm::ImmutableList<SVal> vals) {
215    return nonloc::CompoundVal(BasicVals.getCompoundValData(type, vals));
216  }
217
218  NonLoc makeLazyCompoundVal(const StoreRef &store,
219                             const TypedValueRegion *region) {
220    return nonloc::LazyCompoundVal(
221        BasicVals.getLazyCompoundValData(store, region));
222  }
223
224  NonLoc makeZeroArrayIndex() {
225    return nonloc::ConcreteInt(BasicVals.getValue(0, ArrayIndexTy));
226  }
227
228  NonLoc makeArrayIndex(uint64_t idx) {
229    return nonloc::ConcreteInt(BasicVals.getValue(idx, ArrayIndexTy));
230  }
231
232  SVal convertToArrayIndex(SVal val);
233
234  nonloc::ConcreteInt makeIntVal(const IntegerLiteral* integer) {
235    return nonloc::ConcreteInt(
236        BasicVals.getValue(integer->getValue(),
237                     integer->getType()->isUnsignedIntegerOrEnumerationType()));
238  }
239
240  nonloc::ConcreteInt makeBoolVal(const ObjCBoolLiteralExpr *boolean) {
241    return makeTruthVal(boolean->getValue(), boolean->getType());
242  }
243
244  nonloc::ConcreteInt makeBoolVal(const CXXBoolLiteralExpr *boolean);
245
246  nonloc::ConcreteInt makeIntVal(const llvm::APSInt& integer) {
247    return nonloc::ConcreteInt(BasicVals.getValue(integer));
248  }
249
250  loc::ConcreteInt makeIntLocVal(const llvm::APSInt &integer) {
251    return loc::ConcreteInt(BasicVals.getValue(integer));
252  }
253
254  NonLoc makeIntVal(const llvm::APInt& integer, bool isUnsigned) {
255    return nonloc::ConcreteInt(BasicVals.getValue(integer, isUnsigned));
256  }
257
258  DefinedSVal makeIntVal(uint64_t integer, QualType type) {
259    if (Loc::isLocType(type))
260      return loc::ConcreteInt(BasicVals.getValue(integer, type));
261
262    return nonloc::ConcreteInt(BasicVals.getValue(integer, type));
263  }
264
265  NonLoc makeIntVal(uint64_t integer, bool isUnsigned) {
266    return nonloc::ConcreteInt(BasicVals.getIntValue(integer, isUnsigned));
267  }
268
269  NonLoc makeIntValWithPtrWidth(uint64_t integer, bool isUnsigned) {
270    return nonloc::ConcreteInt(
271        BasicVals.getIntWithPtrWidth(integer, isUnsigned));
272  }
273
274  NonLoc makeLocAsInteger(Loc loc, unsigned bits) {
275    return nonloc::LocAsInteger(BasicVals.getPersistentSValWithData(loc, bits));
276  }
277
278  NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
279                    const llvm::APSInt& rhs, QualType type);
280
281  NonLoc makeNonLoc(const llvm::APSInt& rhs, BinaryOperator::Opcode op,
282                    const SymExpr *lhs, QualType type);
283
284  NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
285                    const SymExpr *rhs, QualType type);
286
287  /// \brief Create a NonLoc value for cast.
288  NonLoc makeNonLoc(const SymExpr *operand, QualType fromTy, QualType toTy);
289
290  nonloc::ConcreteInt makeTruthVal(bool b, QualType type) {
291    return nonloc::ConcreteInt(BasicVals.getTruthValue(b, type));
292  }
293
294  nonloc::ConcreteInt makeTruthVal(bool b) {
295    return nonloc::ConcreteInt(BasicVals.getTruthValue(b));
296  }
297
298  Loc makeNull() {
299    return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth());
300  }
301
302  Loc makeLoc(SymbolRef sym) {
303    return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
304  }
305
306  Loc makeLoc(const MemRegion* region) {
307    return loc::MemRegionVal(region);
308  }
309
310  Loc makeLoc(const AddrLabelExpr *expr) {
311    return loc::GotoLabel(expr->getLabel());
312  }
313
314  Loc makeLoc(const llvm::APSInt& integer) {
315    return loc::ConcreteInt(BasicVals.getValue(integer));
316  }
317
318  /// Return a memory region for the 'this' object reference.
319  loc::MemRegionVal getCXXThis(const CXXMethodDecl *D,
320                               const StackFrameContext *SFC);
321
322  /// Return a memory region for the 'this' object reference.
323  loc::MemRegionVal getCXXThis(const CXXRecordDecl *D,
324                               const StackFrameContext *SFC);
325};
326
327SValBuilder* createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc,
328                                     ASTContext &context,
329                                     ProgramStateManager &stateMgr);
330
331} // end GR namespace
332
333} // end clang namespace
334
335#endif
336