1 //= RValues.cpp - Abstract RValues for Path-Sens. Value Tracking -*- 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 SVal, Loc, and NonLoc, classes that represent
11 // abstract r-values for use with path-sensitive value tracking.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
16 #include "clang/AST/ExprObjC.h"
17 #include "clang/Basic/IdentifierTable.h"
18 using namespace clang;
19 using namespace ento;
20 using llvm::APSInt;
21
22 //===----------------------------------------------------------------------===//
23 // Symbol iteration within an SVal.
24 //===----------------------------------------------------------------------===//
25
26
27 //===----------------------------------------------------------------------===//
28 // Utility methods.
29 //===----------------------------------------------------------------------===//
30
hasConjuredSymbol() const31 bool SVal::hasConjuredSymbol() const {
32 if (const nonloc::SymbolVal* SV = dyn_cast<nonloc::SymbolVal>(this)) {
33 SymbolRef sym = SV->getSymbol();
34 if (isa<SymbolConjured>(sym))
35 return true;
36 }
37
38 if (const loc::MemRegionVal *RV = dyn_cast<loc::MemRegionVal>(this)) {
39 const MemRegion *R = RV->getRegion();
40 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
41 SymbolRef sym = SR->getSymbol();
42 if (isa<SymbolConjured>(sym))
43 return true;
44 }
45 }
46
47 return false;
48 }
49
getAsFunctionDecl() const50 const FunctionDecl *SVal::getAsFunctionDecl() const {
51 if (const loc::MemRegionVal* X = dyn_cast<loc::MemRegionVal>(this)) {
52 const MemRegion* R = X->getRegion();
53 if (const FunctionTextRegion *CTR = R->getAs<FunctionTextRegion>())
54 return CTR->getDecl();
55 }
56
57 return 0;
58 }
59
60 /// \brief If this SVal is a location (subclasses Loc) and wraps a symbol,
61 /// return that SymbolRef. Otherwise return 0.
62 ///
63 /// Implicit casts (ex: void* -> char*) can turn Symbolic region into Element
64 /// region. If that is the case, gets the underlining region.
getAsLocSymbol() const65 SymbolRef SVal::getAsLocSymbol() const {
66 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion?
67 if (const nonloc::LocAsInteger *X = dyn_cast<nonloc::LocAsInteger>(this))
68 return X->getLoc().getAsLocSymbol();
69
70 if (const loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(this)) {
71 const MemRegion *R = X->stripCasts();
72 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(R))
73 return SymR->getSymbol();
74 }
75 return 0;
76 }
77
78 /// Get the symbol in the SVal or its base region.
getLocSymbolInBase() const79 SymbolRef SVal::getLocSymbolInBase() const {
80 const loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(this);
81
82 if (!X)
83 return 0;
84
85 const MemRegion *R = X->getRegion();
86
87 while (const SubRegion *SR = dyn_cast<SubRegion>(R)) {
88 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(SR))
89 return SymR->getSymbol();
90 else
91 R = SR->getSuperRegion();
92 }
93
94 return 0;
95 }
96
97 // TODO: The next 3 functions have to be simplified.
98
99 /// \brief If this SVal wraps a symbol return that SymbolRef.
100 /// Otherwise return 0.
getAsSymbol() const101 SymbolRef SVal::getAsSymbol() const {
102 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion?
103 if (const nonloc::SymbolVal *X = dyn_cast<nonloc::SymbolVal>(this))
104 return X->getSymbol();
105
106 return getAsLocSymbol();
107 }
108
109 /// getAsSymbolicExpression - If this Sval wraps a symbolic expression then
110 /// return that expression. Otherwise return NULL.
getAsSymbolicExpression() const111 const SymExpr *SVal::getAsSymbolicExpression() const {
112 if (const nonloc::SymbolVal *X = dyn_cast<nonloc::SymbolVal>(this))
113 return X->getSymbol();
114
115 return getAsSymbol();
116 }
117
getAsSymExpr() const118 const SymExpr* SVal::getAsSymExpr() const {
119 const SymExpr* Sym = getAsSymbol();
120 if (!Sym)
121 Sym = getAsSymbolicExpression();
122 return Sym;
123 }
124
getAsRegion() const125 const MemRegion *SVal::getAsRegion() const {
126 if (const loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(this))
127 return X->getRegion();
128
129 if (const nonloc::LocAsInteger *X = dyn_cast<nonloc::LocAsInteger>(this)) {
130 return X->getLoc().getAsRegion();
131 }
132
133 return 0;
134 }
135
stripCasts(bool StripBaseCasts) const136 const MemRegion *loc::MemRegionVal::stripCasts(bool StripBaseCasts) const {
137 const MemRegion *R = getRegion();
138 return R ? R->StripCasts(StripBaseCasts) : NULL;
139 }
140
getStore() const141 const void *nonloc::LazyCompoundVal::getStore() const {
142 return static_cast<const LazyCompoundValData*>(Data)->getStore();
143 }
144
getRegion() const145 const TypedRegion *nonloc::LazyCompoundVal::getRegion() const {
146 return static_cast<const LazyCompoundValData*>(Data)->getRegion();
147 }
148
149 //===----------------------------------------------------------------------===//
150 // Other Iterators.
151 //===----------------------------------------------------------------------===//
152
begin() const153 nonloc::CompoundVal::iterator nonloc::CompoundVal::begin() const {
154 return getValue()->begin();
155 }
156
end() const157 nonloc::CompoundVal::iterator nonloc::CompoundVal::end() const {
158 return getValue()->end();
159 }
160
161 //===----------------------------------------------------------------------===//
162 // Useful predicates.
163 //===----------------------------------------------------------------------===//
164
isConstant() const165 bool SVal::isConstant() const {
166 return isa<nonloc::ConcreteInt>(this) || isa<loc::ConcreteInt>(this);
167 }
168
isConstant(int I) const169 bool SVal::isConstant(int I) const {
170 if (isa<loc::ConcreteInt>(*this))
171 return cast<loc::ConcreteInt>(*this).getValue() == I;
172 else if (isa<nonloc::ConcreteInt>(*this))
173 return cast<nonloc::ConcreteInt>(*this).getValue() == I;
174 else
175 return false;
176 }
177
isZeroConstant() const178 bool SVal::isZeroConstant() const {
179 return isConstant(0);
180 }
181
182
183 //===----------------------------------------------------------------------===//
184 // Transfer function dispatch for Non-Locs.
185 //===----------------------------------------------------------------------===//
186
evalBinOp(SValBuilder & svalBuilder,BinaryOperator::Opcode Op,const nonloc::ConcreteInt & R) const187 SVal nonloc::ConcreteInt::evalBinOp(SValBuilder &svalBuilder,
188 BinaryOperator::Opcode Op,
189 const nonloc::ConcreteInt& R) const {
190 const llvm::APSInt* X =
191 svalBuilder.getBasicValueFactory().evalAPSInt(Op, getValue(), R.getValue());
192
193 if (X)
194 return nonloc::ConcreteInt(*X);
195 else
196 return UndefinedVal();
197 }
198
199 nonloc::ConcreteInt
evalComplement(SValBuilder & svalBuilder) const200 nonloc::ConcreteInt::evalComplement(SValBuilder &svalBuilder) const {
201 return svalBuilder.makeIntVal(~getValue());
202 }
203
204 nonloc::ConcreteInt
evalMinus(SValBuilder & svalBuilder) const205 nonloc::ConcreteInt::evalMinus(SValBuilder &svalBuilder) const {
206 return svalBuilder.makeIntVal(-getValue());
207 }
208
209 //===----------------------------------------------------------------------===//
210 // Transfer function dispatch for Locs.
211 //===----------------------------------------------------------------------===//
212
evalBinOp(BasicValueFactory & BasicVals,BinaryOperator::Opcode Op,const loc::ConcreteInt & R) const213 SVal loc::ConcreteInt::evalBinOp(BasicValueFactory& BasicVals,
214 BinaryOperator::Opcode Op,
215 const loc::ConcreteInt& R) const {
216
217 assert (Op == BO_Add || Op == BO_Sub ||
218 (Op >= BO_LT && Op <= BO_NE));
219
220 const llvm::APSInt* X = BasicVals.evalAPSInt(Op, getValue(), R.getValue());
221
222 if (X)
223 return loc::ConcreteInt(*X);
224 else
225 return UndefinedVal();
226 }
227
228 //===----------------------------------------------------------------------===//
229 // Pretty-Printing.
230 //===----------------------------------------------------------------------===//
231
dump() const232 void SVal::dump() const { dumpToStream(llvm::errs()); }
233
dumpToStream(raw_ostream & os) const234 void SVal::dumpToStream(raw_ostream &os) const {
235 switch (getBaseKind()) {
236 case UnknownKind:
237 os << "Unknown";
238 break;
239 case NonLocKind:
240 cast<NonLoc>(this)->dumpToStream(os);
241 break;
242 case LocKind:
243 cast<Loc>(this)->dumpToStream(os);
244 break;
245 case UndefinedKind:
246 os << "Undefined";
247 break;
248 }
249 }
250
dumpToStream(raw_ostream & os) const251 void NonLoc::dumpToStream(raw_ostream &os) const {
252 switch (getSubKind()) {
253 case nonloc::ConcreteIntKind: {
254 const nonloc::ConcreteInt& C = *cast<nonloc::ConcreteInt>(this);
255 if (C.getValue().isUnsigned())
256 os << C.getValue().getZExtValue();
257 else
258 os << C.getValue().getSExtValue();
259 os << ' ' << (C.getValue().isUnsigned() ? 'U' : 'S')
260 << C.getValue().getBitWidth() << 'b';
261 break;
262 }
263 case nonloc::SymbolValKind: {
264 os << cast<nonloc::SymbolVal>(this)->getSymbol();
265 break;
266 }
267 case nonloc::LocAsIntegerKind: {
268 const nonloc::LocAsInteger& C = *cast<nonloc::LocAsInteger>(this);
269 os << C.getLoc() << " [as " << C.getNumBits() << " bit integer]";
270 break;
271 }
272 case nonloc::CompoundValKind: {
273 const nonloc::CompoundVal& C = *cast<nonloc::CompoundVal>(this);
274 os << "compoundVal{";
275 bool first = true;
276 for (nonloc::CompoundVal::iterator I=C.begin(), E=C.end(); I!=E; ++I) {
277 if (first) {
278 os << ' '; first = false;
279 }
280 else
281 os << ", ";
282
283 (*I).dumpToStream(os);
284 }
285 os << "}";
286 break;
287 }
288 case nonloc::LazyCompoundValKind: {
289 const nonloc::LazyCompoundVal &C = *cast<nonloc::LazyCompoundVal>(this);
290 os << "lazyCompoundVal{" << const_cast<void *>(C.getStore())
291 << ',' << C.getRegion()
292 << '}';
293 break;
294 }
295 default:
296 assert (false && "Pretty-printed not implemented for this NonLoc.");
297 break;
298 }
299 }
300
dumpToStream(raw_ostream & os) const301 void Loc::dumpToStream(raw_ostream &os) const {
302 switch (getSubKind()) {
303 case loc::ConcreteIntKind:
304 os << cast<loc::ConcreteInt>(this)->getValue().getZExtValue() << " (Loc)";
305 break;
306 case loc::GotoLabelKind:
307 os << "&&" << cast<loc::GotoLabel>(this)->getLabel()->getName();
308 break;
309 case loc::MemRegionKind:
310 os << '&' << cast<loc::MemRegionVal>(this)->getRegion()->getString();
311 break;
312 default:
313 llvm_unreachable("Pretty-printing not implemented for this Loc.");
314 }
315 }
316