SValBuilder.h revision c35fb7d67d515659ad2325b4f6ec97c9fe64fb63 
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/StaticAnalyzer/Core/PathSensitive/SVals.h"
20#include "clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h"
21#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
22
23namespace clang {
24
25class CXXBoolLiteralExpr;
26
27namespace ento {
28
29class SValBuilder {
30  virtual void anchor();
31protected:
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  ProgramStateManager &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  virtual SVal evalCastFromNonLoc(NonLoc val, QualType castTy) = 0;
52  virtual SVal evalCastFromLoc(Loc val, QualType castTy) = 0;
53
54public:
55  // FIXME: Make these protected again once RegionStoreManager correctly
56  // handles loads from different bound value types.
57  virtual SVal dispatchCast(SVal val, QualType castTy) = 0;
58
59public:
60  SValBuilder(llvm::BumpPtrAllocator &alloc, ASTContext &context,
61              ProgramStateManager &stateMgr)
62    : Context(context), BasicVals(context, alloc),
63      SymMgr(context, BasicVals, alloc),
64      MemMgr(context, alloc),
65      StateMgr(stateMgr),
66      ArrayIndexTy(context.IntTy),
67      ArrayIndexWidth(context.getTypeSize(ArrayIndexTy)) {}
68
69  virtual ~SValBuilder() {}
70
71  bool haveSameType(const SymExpr *Sym1, const SymExpr *Sym2) {
72    return haveSameType(Sym1->getType(Context), Sym2->getType(Context));
73  }
74
75  bool haveSameType(QualType Ty1, QualType Ty2) {
76    // FIXME: Remove the second disjunct when we support symbolic
77    // truncation/extension.
78    return (Context.getCanonicalType(Ty1) == Context.getCanonicalType(Ty2) ||
79            (Ty2->isIntegerType() && Ty2->isIntegerType()));
80  }
81
82  SVal evalCast(SVal val, QualType castTy, QualType originalType);
83
84  virtual SVal evalMinus(NonLoc val) = 0;
85
86  virtual SVal evalComplement(NonLoc val) = 0;
87
88  /// Create a new value which represents a binary expression with two non
89  /// location operands.
90  virtual SVal evalBinOpNN(ProgramStateRef state, BinaryOperator::Opcode op,
91                           NonLoc lhs, NonLoc rhs, QualType resultTy) = 0;
92
93  /// Create a new value which represents a binary expression with two memory
94  /// location operands.
95  virtual SVal evalBinOpLL(ProgramStateRef state, BinaryOperator::Opcode op,
96                           Loc lhs, Loc rhs, QualType resultTy) = 0;
97
98  /// Create a new value which represents a binary expression with a memory
99  /// location and non location operands. For example, this would be used to
100  /// evaluate a pointer arithmetic operation.
101  virtual SVal evalBinOpLN(ProgramStateRef state, BinaryOperator::Opcode op,
102                           Loc lhs, NonLoc rhs, QualType resultTy) = 0;
103
104  /// Evaluates a given SVal. If the SVal has only one possible (integer) value,
105  /// that value is returned. Otherwise, returns NULL.
106  virtual const llvm::APSInt *getKnownValue(ProgramStateRef state, SVal val) = 0;
107
108  /// Handles generation of the value in case the builder is not smart enough to
109  /// handle the given binary expression. Depending on the state, decides to
110  /// either keep the expression or forget the history and generate an
111  /// UnknownVal.
112  SVal makeGenericVal(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* getConjuredSymbol(const Stmt *stmt, QualType type,
146                                          unsigned visitCount,
147                                          const void *symbolTag = 0) {
148    return SymMgr.getConjuredSymbol(stmt, type, visitCount, symbolTag);
149  }
150
151  const SymbolConjured* getConjuredSymbol(const Expr *expr, unsigned visitCount,
152                                          const void *symbolTag = 0) {
153    return SymMgr.getConjuredSymbol(expr, visitCount, symbolTag);
154  }
155
156  /// Construct an SVal representing '0' for the specified type.
157  DefinedOrUnknownSVal makeZeroVal(QualType type);
158
159  /// Make a unique symbol for value of region.
160  DefinedOrUnknownSVal getRegionValueSymbolVal(const TypedValueRegion *region);
161
162  /// \brief Create a new symbol with a unique 'name'.
163  ///
164  /// We resort to conjured symbols when we cannot construct a derived symbol.
165  /// The advantage of symbols derived/built from other symbols is that we
166  /// preserve the relation between related(or even equivalent) expressions, so
167  /// conjured symbols should be used sparingly.
168  DefinedOrUnknownSVal getConjuredSymbolVal(const void *symbolTag,
169                                            const Expr *expr, unsigned count);
170  DefinedOrUnknownSVal getConjuredSymbolVal(const void *symbolTag,
171                                            const Expr *expr, QualType type,
172                                            unsigned count);
173
174  DefinedOrUnknownSVal getDerivedRegionValueSymbolVal(
175      SymbolRef parentSymbol, const TypedValueRegion *region);
176
177  DefinedSVal getMetadataSymbolVal(
178      const void *symbolTag, const MemRegion *region,
179      const Expr *expr, QualType type, unsigned count);
180
181  DefinedSVal getFunctionPointer(const FunctionDecl *func);
182
183  DefinedSVal getBlockPointer(const BlockDecl *block, CanQualType locTy,
184                              const LocationContext *locContext);
185
186  NonLoc makeCompoundVal(QualType type, llvm::ImmutableList<SVal> vals) {
187    return nonloc::CompoundVal(BasicVals.getCompoundValData(type, vals));
188  }
189
190  NonLoc makeLazyCompoundVal(const StoreRef &store,
191                             const TypedValueRegion *region) {
192    return nonloc::LazyCompoundVal(
193        BasicVals.getLazyCompoundValData(store, region));
194  }
195
196  NonLoc makeZeroArrayIndex() {
197    return nonloc::ConcreteInt(BasicVals.getValue(0, ArrayIndexTy));
198  }
199
200  NonLoc makeArrayIndex(uint64_t idx) {
201    return nonloc::ConcreteInt(BasicVals.getValue(idx, ArrayIndexTy));
202  }
203
204  SVal convertToArrayIndex(SVal val);
205
206  nonloc::ConcreteInt makeIntVal(const IntegerLiteral* integer) {
207    return nonloc::ConcreteInt(
208        BasicVals.getValue(integer->getValue(),
209                     integer->getType()->isUnsignedIntegerOrEnumerationType()));
210  }
211
212  nonloc::ConcreteInt makeBoolVal(const CXXBoolLiteralExpr *boolean);
213
214  nonloc::ConcreteInt makeIntVal(const llvm::APSInt& integer) {
215    return nonloc::ConcreteInt(BasicVals.getValue(integer));
216  }
217
218  loc::ConcreteInt makeIntLocVal(const llvm::APSInt &integer) {
219    return loc::ConcreteInt(BasicVals.getValue(integer));
220  }
221
222  NonLoc makeIntVal(const llvm::APInt& integer, bool isUnsigned) {
223    return nonloc::ConcreteInt(BasicVals.getValue(integer, isUnsigned));
224  }
225
226  DefinedSVal makeIntVal(uint64_t integer, QualType type) {
227    if (Loc::isLocType(type))
228      return loc::ConcreteInt(BasicVals.getValue(integer, type));
229
230    return nonloc::ConcreteInt(BasicVals.getValue(integer, type));
231  }
232
233  NonLoc makeIntVal(uint64_t integer, bool isUnsigned) {
234    return nonloc::ConcreteInt(BasicVals.getIntValue(integer, isUnsigned));
235  }
236
237  NonLoc makeIntValWithPtrWidth(uint64_t integer, bool isUnsigned) {
238    return nonloc::ConcreteInt(
239        BasicVals.getIntWithPtrWidth(integer, isUnsigned));
240  }
241
242  NonLoc makeIntVal(uint64_t integer, unsigned bitWidth, bool isUnsigned) {
243    return nonloc::ConcreteInt(
244        BasicVals.getValue(integer, bitWidth, isUnsigned));
245  }
246
247  NonLoc makeLocAsInteger(Loc loc, unsigned bits) {
248    return nonloc::LocAsInteger(BasicVals.getPersistentSValWithData(loc, bits));
249  }
250
251  NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
252                    const llvm::APSInt& rhs, QualType type);
253
254  NonLoc makeNonLoc(const llvm::APSInt& rhs, BinaryOperator::Opcode op,
255                    const SymExpr *lhs, QualType type);
256
257  NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
258                    const SymExpr *rhs, QualType type);
259
260  /// \brief Create a NonLoc value for cast.
261  NonLoc makeNonLoc(const SymExpr *operand, QualType fromTy, QualType toTy);
262
263  nonloc::ConcreteInt makeTruthVal(bool b, QualType type) {
264    return nonloc::ConcreteInt(BasicVals.getTruthValue(b, type));
265  }
266
267  nonloc::ConcreteInt makeTruthVal(bool b) {
268    return nonloc::ConcreteInt(BasicVals.getTruthValue(b));
269  }
270
271  Loc makeNull() {
272    return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth());
273  }
274
275  Loc makeLoc(SymbolRef sym) {
276    return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
277  }
278
279  Loc makeLoc(const MemRegion* region) {
280    return loc::MemRegionVal(region);
281  }
282
283  Loc makeLoc(const AddrLabelExpr *expr) {
284    return loc::GotoLabel(expr->getLabel());
285  }
286
287  Loc makeLoc(const llvm::APSInt& integer) {
288    return loc::ConcreteInt(BasicVals.getValue(integer));
289  }
290
291};
292
293SValBuilder* createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc,
294                                     ASTContext &context,
295                                     ProgramStateManager &stateMgr);
296
297} // end GR namespace
298
299} // end clang namespace
300
301#endif
302