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 #include "llvm/Support/raw_ostream.h"
19 using namespace clang;
20 using namespace ento;
21 using llvm::APSInt;
22
23 //===----------------------------------------------------------------------===//
24 // Symbol iteration within an SVal.
25 //===----------------------------------------------------------------------===//
26
27
28 //===----------------------------------------------------------------------===//
29 // Utility methods.
30 //===----------------------------------------------------------------------===//
31
hasConjuredSymbol() const32 bool SVal::hasConjuredSymbol() const {
33 if (Optional<nonloc::SymbolVal> SV = getAs<nonloc::SymbolVal>()) {
34 SymbolRef sym = SV->getSymbol();
35 if (isa<SymbolConjured>(sym))
36 return true;
37 }
38
39 if (Optional<loc::MemRegionVal> RV = getAs<loc::MemRegionVal>()) {
40 const MemRegion *R = RV->getRegion();
41 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
42 SymbolRef sym = SR->getSymbol();
43 if (isa<SymbolConjured>(sym))
44 return true;
45 }
46 }
47
48 return false;
49 }
50
getAsFunctionDecl() const51 const FunctionDecl *SVal::getAsFunctionDecl() const {
52 if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) {
53 const MemRegion* R = X->getRegion();
54 if (const FunctionTextRegion *CTR = R->getAs<FunctionTextRegion>())
55 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CTR->getDecl()))
56 return FD;
57 }
58
59 return 0;
60 }
61
62 /// \brief If this SVal is a location (subclasses Loc) and wraps a symbol,
63 /// return that SymbolRef. Otherwise return 0.
64 ///
65 /// Implicit casts (ex: void* -> char*) can turn Symbolic region into Element
66 /// region. If that is the case, gets the underlining region.
getAsLocSymbol() const67 SymbolRef SVal::getAsLocSymbol() const {
68 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion?
69 if (Optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>())
70 return X->getLoc().getAsLocSymbol();
71
72 if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) {
73 const MemRegion *R = X->stripCasts();
74 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(R))
75 return SymR->getSymbol();
76 }
77 return 0;
78 }
79
80 /// Get the symbol in the SVal or its base region.
getLocSymbolInBase() const81 SymbolRef SVal::getLocSymbolInBase() const {
82 Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>();
83
84 if (!X)
85 return 0;
86
87 const MemRegion *R = X->getRegion();
88
89 while (const SubRegion *SR = dyn_cast<SubRegion>(R)) {
90 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(SR))
91 return SymR->getSymbol();
92 else
93 R = SR->getSuperRegion();
94 }
95
96 return 0;
97 }
98
99 // TODO: The next 3 functions have to be simplified.
100
101 /// \brief If this SVal wraps a symbol return that SymbolRef.
102 /// Otherwise return 0.
getAsSymbol() const103 SymbolRef SVal::getAsSymbol() const {
104 // FIXME: should we consider SymbolRef wrapped in CodeTextRegion?
105 if (Optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>())
106 return X->getSymbol();
107
108 return getAsLocSymbol();
109 }
110
111 /// getAsSymbolicExpression - If this Sval wraps a symbolic expression then
112 /// return that expression. Otherwise return NULL.
getAsSymbolicExpression() const113 const SymExpr *SVal::getAsSymbolicExpression() const {
114 if (Optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>())
115 return X->getSymbol();
116
117 return getAsSymbol();
118 }
119
getAsSymExpr() const120 const SymExpr* SVal::getAsSymExpr() const {
121 const SymExpr* Sym = getAsSymbol();
122 if (!Sym)
123 Sym = getAsSymbolicExpression();
124 return Sym;
125 }
126
getAsRegion() const127 const MemRegion *SVal::getAsRegion() const {
128 if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>())
129 return X->getRegion();
130
131 if (Optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>())
132 return X->getLoc().getAsRegion();
133
134 return 0;
135 }
136
stripCasts(bool StripBaseCasts) const137 const MemRegion *loc::MemRegionVal::stripCasts(bool StripBaseCasts) const {
138 const MemRegion *R = getRegion();
139 return R ? R->StripCasts(StripBaseCasts) : NULL;
140 }
141
getStore() const142 const void *nonloc::LazyCompoundVal::getStore() const {
143 return static_cast<const LazyCompoundValData*>(Data)->getStore();
144 }
145
getRegion() const146 const TypedValueRegion *nonloc::LazyCompoundVal::getRegion() const {
147 return static_cast<const LazyCompoundValData*>(Data)->getRegion();
148 }
149
150 //===----------------------------------------------------------------------===//
151 // Other Iterators.
152 //===----------------------------------------------------------------------===//
153
begin() const154 nonloc::CompoundVal::iterator nonloc::CompoundVal::begin() const {
155 return getValue()->begin();
156 }
157
end() const158 nonloc::CompoundVal::iterator nonloc::CompoundVal::end() const {
159 return getValue()->end();
160 }
161
162 //===----------------------------------------------------------------------===//
163 // Useful predicates.
164 //===----------------------------------------------------------------------===//
165
isConstant() const166 bool SVal::isConstant() const {
167 return getAs<nonloc::ConcreteInt>() || getAs<loc::ConcreteInt>();
168 }
169
isConstant(int I) const170 bool SVal::isConstant(int I) const {
171 if (Optional<loc::ConcreteInt> LV = getAs<loc::ConcreteInt>())
172 return LV->getValue() == I;
173 if (Optional<nonloc::ConcreteInt> NV = getAs<nonloc::ConcreteInt>())
174 return NV->getValue() == I;
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 castAs<NonLoc>().dumpToStream(os);
241 break;
242 case LocKind:
243 castAs<Loc>().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 = castAs<nonloc::ConcreteInt>();
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 << castAs<nonloc::SymbolVal>().getSymbol();
265 break;
266 }
267 case nonloc::LocAsIntegerKind: {
268 const nonloc::LocAsInteger& C = castAs<nonloc::LocAsInteger>();
269 os << C.getLoc() << " [as " << C.getNumBits() << " bit integer]";
270 break;
271 }
272 case nonloc::CompoundValKind: {
273 const nonloc::CompoundVal& C = castAs<nonloc::CompoundVal>();
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 = castAs<nonloc::LazyCompoundVal>();
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 << castAs<loc::ConcreteInt>().getValue().getZExtValue() << " (Loc)";
305 break;
306 case loc::GotoLabelKind:
307 os << "&&" << castAs<loc::GotoLabel>().getLabel()->getName();
308 break;
309 case loc::MemRegionKind:
310 os << '&' << castAs<loc::MemRegionVal>().getRegion()->getString();
311 break;
312 default:
313 llvm_unreachable("Pretty-printing not implemented for this Loc.");
314 }
315 }
316