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_STATICANALYZER_CORE_PATHSENSITIVE_SVALBUILDER_H
16#define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SVALBUILDER_H
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#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.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.LongLongTy),
70      ArrayIndexWidth(context.getTypeSize(ArrayIndexTy)) {}
71
72  virtual ~SValBuilder() {}
73
74  bool haveSameType(const SymExpr *Sym1, const SymExpr *Sym2) {
75    return haveSameType(Sym1->getType(), Sym2->getType());
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->isIntegralOrEnumerationType() &&
83             Ty2->isIntegralOrEnumerationType()));
84  }
85
86  SVal evalCast(SVal val, QualType castTy, QualType originalType);
87
88  // Handles casts of type CK_IntegralCast.
89  SVal evalIntegralCast(ProgramStateRef state, SVal val, QualType castTy,
90                        QualType originalType);
91
92  virtual SVal evalMinus(NonLoc val) = 0;
93
94  virtual SVal evalComplement(NonLoc val) = 0;
95
96  /// Create a new value which represents a binary expression with two non-
97  /// location operands.
98  virtual SVal evalBinOpNN(ProgramStateRef state, BinaryOperator::Opcode op,
99                           NonLoc lhs, NonLoc rhs, QualType resultTy) = 0;
100
101  /// Create a new value which represents a binary expression with two memory
102  /// location operands.
103  virtual SVal evalBinOpLL(ProgramStateRef state, BinaryOperator::Opcode op,
104                           Loc lhs, Loc rhs, QualType resultTy) = 0;
105
106  /// Create a new value which represents a binary expression with a memory
107  /// location and non-location operands. For example, this would be used to
108  /// evaluate a pointer arithmetic operation.
109  virtual SVal evalBinOpLN(ProgramStateRef state, BinaryOperator::Opcode op,
110                           Loc lhs, NonLoc rhs, QualType resultTy) = 0;
111
112  /// Evaluates a given SVal. If the SVal has only one possible (integer) value,
113  /// that value is returned. Otherwise, returns NULL.
114  virtual const llvm::APSInt *getKnownValue(ProgramStateRef state, SVal val) = 0;
115
116  /// Constructs a symbolic expression for two non-location values.
117  SVal makeSymExprValNN(ProgramStateRef state, BinaryOperator::Opcode op,
118                      NonLoc lhs, NonLoc rhs, QualType resultTy);
119
120  SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op,
121                 SVal lhs, SVal rhs, QualType type);
122
123  DefinedOrUnknownSVal evalEQ(ProgramStateRef state, DefinedOrUnknownSVal lhs,
124                              DefinedOrUnknownSVal rhs);
125
126  ASTContext &getContext() { return Context; }
127  const ASTContext &getContext() const { return Context; }
128
129  ProgramStateManager &getStateManager() { return StateMgr; }
130
131  QualType getConditionType() const {
132    return Context.getLangOpts().CPlusPlus ? Context.BoolTy : Context.IntTy;
133  }
134
135  QualType getArrayIndexType() const {
136    return ArrayIndexTy;
137  }
138
139  BasicValueFactory &getBasicValueFactory() { return BasicVals; }
140  const BasicValueFactory &getBasicValueFactory() const { return BasicVals; }
141
142  SymbolManager &getSymbolManager() { return SymMgr; }
143  const SymbolManager &getSymbolManager() const { return SymMgr; }
144
145  MemRegionManager &getRegionManager() { return MemMgr; }
146  const MemRegionManager &getRegionManager() const { return MemMgr; }
147
148  // Forwarding methods to SymbolManager.
149
150  const SymbolConjured* conjureSymbol(const Stmt *stmt,
151                                      const LocationContext *LCtx,
152                                      QualType type,
153                                      unsigned visitCount,
154                                      const void *symbolTag = nullptr) {
155    return SymMgr.conjureSymbol(stmt, LCtx, type, visitCount, symbolTag);
156  }
157
158  const SymbolConjured* conjureSymbol(const Expr *expr,
159                                      const LocationContext *LCtx,
160                                      unsigned visitCount,
161                                      const void *symbolTag = nullptr) {
162    return SymMgr.conjureSymbol(expr, LCtx, visitCount, symbolTag);
163  }
164
165  /// Construct an SVal representing '0' for the specified type.
166  DefinedOrUnknownSVal makeZeroVal(QualType type);
167
168  /// Make a unique symbol for value of region.
169  DefinedOrUnknownSVal getRegionValueSymbolVal(const TypedValueRegion *region);
170
171  /// \brief Create a new symbol with a unique 'name'.
172  ///
173  /// We resort to conjured symbols when we cannot construct a derived symbol.
174  /// The advantage of symbols derived/built from other symbols is that we
175  /// preserve the relation between related(or even equivalent) expressions, so
176  /// conjured symbols should be used sparingly.
177  DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag,
178                                        const Expr *expr,
179                                        const LocationContext *LCtx,
180                                        unsigned count);
181  DefinedOrUnknownSVal conjureSymbolVal(const void *symbolTag,
182                                        const Expr *expr,
183                                        const LocationContext *LCtx,
184                                        QualType type,
185                                        unsigned count);
186
187  DefinedOrUnknownSVal conjureSymbolVal(const Stmt *stmt,
188                                        const LocationContext *LCtx,
189                                        QualType type,
190                                        unsigned visitCount);
191  /// \brief Conjure a symbol representing heap allocated memory region.
192  ///
193  /// Note, the expression should represent a location.
194  DefinedOrUnknownSVal getConjuredHeapSymbolVal(const Expr *E,
195                                                const LocationContext *LCtx,
196                                                unsigned Count);
197
198  DefinedOrUnknownSVal getDerivedRegionValueSymbolVal(
199      SymbolRef parentSymbol, const TypedValueRegion *region);
200
201  DefinedSVal getMetadataSymbolVal(
202      const void *symbolTag, const MemRegion *region,
203      const Expr *expr, QualType type, unsigned count);
204
205  DefinedSVal getFunctionPointer(const FunctionDecl *func);
206
207  DefinedSVal getBlockPointer(const BlockDecl *block, CanQualType locTy,
208                              const LocationContext *locContext,
209                              unsigned blockCount);
210
211  /// Returns the value of \p E, if it can be determined in a non-path-sensitive
212  /// manner.
213  ///
214  /// If \p E is not a constant or cannot be modeled, returns \c None.
215  Optional<SVal> getConstantVal(const Expr *E);
216
217  NonLoc makeCompoundVal(QualType type, llvm::ImmutableList<SVal> vals) {
218    return nonloc::CompoundVal(BasicVals.getCompoundValData(type, vals));
219  }
220
221  NonLoc makeLazyCompoundVal(const StoreRef &store,
222                             const TypedValueRegion *region) {
223    return nonloc::LazyCompoundVal(
224        BasicVals.getLazyCompoundValData(store, region));
225  }
226
227  NonLoc makeZeroArrayIndex() {
228    return nonloc::ConcreteInt(BasicVals.getValue(0, ArrayIndexTy));
229  }
230
231  NonLoc makeArrayIndex(uint64_t idx) {
232    return nonloc::ConcreteInt(BasicVals.getValue(idx, ArrayIndexTy));
233  }
234
235  SVal convertToArrayIndex(SVal val);
236
237  nonloc::ConcreteInt makeIntVal(const IntegerLiteral* integer) {
238    return nonloc::ConcreteInt(
239        BasicVals.getValue(integer->getValue(),
240                     integer->getType()->isUnsignedIntegerOrEnumerationType()));
241  }
242
243  nonloc::ConcreteInt makeBoolVal(const ObjCBoolLiteralExpr *boolean) {
244    return makeTruthVal(boolean->getValue(), boolean->getType());
245  }
246
247  nonloc::ConcreteInt makeBoolVal(const CXXBoolLiteralExpr *boolean);
248
249  nonloc::ConcreteInt makeIntVal(const llvm::APSInt& integer) {
250    return nonloc::ConcreteInt(BasicVals.getValue(integer));
251  }
252
253  loc::ConcreteInt makeIntLocVal(const llvm::APSInt &integer) {
254    return loc::ConcreteInt(BasicVals.getValue(integer));
255  }
256
257  NonLoc makeIntVal(const llvm::APInt& integer, bool isUnsigned) {
258    return nonloc::ConcreteInt(BasicVals.getValue(integer, isUnsigned));
259  }
260
261  DefinedSVal makeIntVal(uint64_t integer, QualType type) {
262    if (Loc::isLocType(type))
263      return loc::ConcreteInt(BasicVals.getValue(integer, type));
264
265    return nonloc::ConcreteInt(BasicVals.getValue(integer, type));
266  }
267
268  NonLoc makeIntVal(uint64_t integer, bool isUnsigned) {
269    return nonloc::ConcreteInt(BasicVals.getIntValue(integer, isUnsigned));
270  }
271
272  NonLoc makeIntValWithPtrWidth(uint64_t integer, bool isUnsigned) {
273    return nonloc::ConcreteInt(
274        BasicVals.getIntWithPtrWidth(integer, isUnsigned));
275  }
276
277  NonLoc makeLocAsInteger(Loc loc, unsigned bits) {
278    return nonloc::LocAsInteger(BasicVals.getPersistentSValWithData(loc, bits));
279  }
280
281  NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
282                    const llvm::APSInt& rhs, QualType type);
283
284  NonLoc makeNonLoc(const llvm::APSInt& rhs, BinaryOperator::Opcode op,
285                    const SymExpr *lhs, QualType type);
286
287  NonLoc makeNonLoc(const SymExpr *lhs, BinaryOperator::Opcode op,
288                    const SymExpr *rhs, QualType type);
289
290  /// \brief Create a NonLoc value for cast.
291  NonLoc makeNonLoc(const SymExpr *operand, QualType fromTy, QualType toTy);
292
293  nonloc::ConcreteInt makeTruthVal(bool b, QualType type) {
294    return nonloc::ConcreteInt(BasicVals.getTruthValue(b, type));
295  }
296
297  nonloc::ConcreteInt makeTruthVal(bool b) {
298    return nonloc::ConcreteInt(BasicVals.getTruthValue(b));
299  }
300
301  Loc makeNull() {
302    return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth());
303  }
304
305  Loc makeLoc(SymbolRef sym) {
306    return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
307  }
308
309  Loc makeLoc(const MemRegion* region) {
310    return loc::MemRegionVal(region);
311  }
312
313  Loc makeLoc(const AddrLabelExpr *expr) {
314    return loc::GotoLabel(expr->getLabel());
315  }
316
317  Loc makeLoc(const llvm::APSInt& integer) {
318    return loc::ConcreteInt(BasicVals.getValue(integer));
319  }
320
321  /// Return a memory region for the 'this' object reference.
322  loc::MemRegionVal getCXXThis(const CXXMethodDecl *D,
323                               const StackFrameContext *SFC);
324
325  /// Return a memory region for the 'this' object reference.
326  loc::MemRegionVal getCXXThis(const CXXRecordDecl *D,
327                               const StackFrameContext *SFC);
328};
329
330SValBuilder* createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc,
331                                     ASTContext &context,
332                                     ProgramStateManager &stateMgr);
333
334} // end GR namespace
335
336} // end clang namespace
337
338#endif
339