clang  8.0.0
SVals.cpp
Go to the documentation of this file.
1 //===- RValues.cpp - Abstract RValues for Path-Sens. Value Tracking -------===//
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 
16 #include "clang/AST/Decl.h"
17 #include "clang/AST/DeclCXX.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/Type.h"
20 #include "clang/Basic/LLVM.h"
26 #include "llvm/ADT/Optional.h"
27 #include "llvm/Support/Casting.h"
28 #include "llvm/Support/Compiler.h"
29 #include "llvm/Support/ErrorHandling.h"
30 #include "llvm/Support/raw_ostream.h"
31 #include <cassert>
32 
33 using namespace clang;
34 using namespace ento;
35 
36 //===----------------------------------------------------------------------===//
37 // Symbol iteration within an SVal.
38 //===----------------------------------------------------------------------===//
39 
40 //===----------------------------------------------------------------------===//
41 // Utility methods.
42 //===----------------------------------------------------------------------===//
43 
45  if (Optional<nonloc::SymbolVal> SV = getAs<nonloc::SymbolVal>()) {
46  SymbolRef sym = SV->getSymbol();
47  if (isa<SymbolConjured>(sym))
48  return true;
49  }
50 
51  if (Optional<loc::MemRegionVal> RV = getAs<loc::MemRegionVal>()) {
52  const MemRegion *R = RV->getRegion();
53  if (const auto *SR = dyn_cast<SymbolicRegion>(R)) {
54  SymbolRef sym = SR->getSymbol();
55  if (isa<SymbolConjured>(sym))
56  return true;
57  }
58  }
59 
60  return false;
61 }
62 
64  if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) {
65  const MemRegion* R = X->getRegion();
66  if (const FunctionCodeRegion *CTR = R->getAs<FunctionCodeRegion>())
67  if (const auto *FD = dyn_cast<FunctionDecl>(CTR->getDecl()))
68  return FD;
69  }
70 
71  if (auto X = getAs<nonloc::PointerToMember>()) {
72  if (const auto *MD = dyn_cast_or_null<CXXMethodDecl>(X->getDecl()))
73  return MD;
74  }
75  return nullptr;
76 }
77 
78 /// If this SVal is a location (subclasses Loc) and wraps a symbol,
79 /// return that SymbolRef. Otherwise return 0.
80 ///
81 /// Implicit casts (ex: void* -> char*) can turn Symbolic region into Element
82 /// region. If that is the case, gets the underlining region.
83 /// When IncludeBaseRegions is set to true and the SubRegion is non-symbolic,
84 /// the first symbolic parent region is returned.
85 SymbolRef SVal::getAsLocSymbol(bool IncludeBaseRegions) const {
86  // FIXME: should we consider SymbolRef wrapped in CodeTextRegion?
87  if (Optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>())
88  return X->getLoc().getAsLocSymbol(IncludeBaseRegions);
89 
90  if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>()) {
91  const MemRegion *R = X->getRegion();
92  if (const SymbolicRegion *SymR = IncludeBaseRegions ?
93  R->getSymbolicBase() :
94  dyn_cast<SymbolicRegion>(R->StripCasts()))
95  return SymR->getSymbol();
96  }
97  return nullptr;
98 }
99 
100 /// Get the symbol in the SVal or its base region.
102  Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>();
103 
104  if (!X)
105  return nullptr;
106 
107  const MemRegion *R = X->getRegion();
108 
109  while (const auto *SR = dyn_cast<SubRegion>(R)) {
110  if (const auto *SymR = dyn_cast<SymbolicRegion>(SR))
111  return SymR->getSymbol();
112  else
113  R = SR->getSuperRegion();
114  }
115 
116  return nullptr;
117 }
118 
119 // TODO: The next 3 functions have to be simplified.
120 
121 /// If this SVal wraps a symbol return that SymbolRef.
122 /// Otherwise, return 0.
123 ///
124 /// Casts are ignored during lookup.
125 /// \param IncludeBaseRegions The boolean that controls whether the search
126 /// should continue to the base regions if the region is not symbolic.
127 SymbolRef SVal::getAsSymbol(bool IncludeBaseRegions) const {
128  // FIXME: should we consider SymbolRef wrapped in CodeTextRegion?
129  if (Optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>())
130  return X->getSymbol();
131 
132  return getAsLocSymbol(IncludeBaseRegions);
133 }
134 
135 /// getAsSymbolicExpression - If this Sval wraps a symbolic expression then
136 /// return that expression. Otherwise return NULL.
138  if (Optional<nonloc::SymbolVal> X = getAs<nonloc::SymbolVal>())
139  return X->getSymbol();
140 
141  return getAsSymbol();
142 }
143 
144 const SymExpr* SVal::getAsSymExpr() const {
145  const SymExpr* Sym = getAsSymbol();
146  if (!Sym)
147  Sym = getAsSymbolicExpression();
148  return Sym;
149 }
150 
151 const MemRegion *SVal::getAsRegion() const {
152  if (Optional<loc::MemRegionVal> X = getAs<loc::MemRegionVal>())
153  return X->getRegion();
154 
155  if (Optional<nonloc::LocAsInteger> X = getAs<nonloc::LocAsInteger>())
156  return X->getLoc().getAsRegion();
157 
158  return nullptr;
159 }
160 
161 const MemRegion *loc::MemRegionVal::stripCasts(bool StripBaseCasts) const {
162  const MemRegion *R = getRegion();
163  return R ? R->StripCasts(StripBaseCasts) : nullptr;
164 }
165 
167  return static_cast<const LazyCompoundValData*>(Data)->getStore();
168 }
169 
171  return static_cast<const LazyCompoundValData*>(Data)->getRegion();
172 }
173 
175  return getPTMData().isNull();
176 }
177 
179  const auto PTMD = this->getPTMData();
180  if (PTMD.isNull())
181  return nullptr;
182 
183  const DeclaratorDecl *DD = nullptr;
184  if (PTMD.is<const DeclaratorDecl *>())
185  DD = PTMD.get<const DeclaratorDecl *>();
186  else
187  DD = PTMD.get<const PointerToMemberData *>()->getDeclaratorDecl();
188 
189  return DD;
190 }
191 
192 //===----------------------------------------------------------------------===//
193 // Other Iterators.
194 //===----------------------------------------------------------------------===//
195 
197  return getValue()->begin();
198 }
199 
201  return getValue()->end();
202 }
203 
205  const PTMDataType PTMD = getPTMData();
206  if (PTMD.is<const DeclaratorDecl *>())
207  return {};
208  return PTMD.get<const PointerToMemberData *>()->begin();
209 }
210 
212  const PTMDataType PTMD = getPTMData();
213  if (PTMD.is<const DeclaratorDecl *>())
214  return {};
215  return PTMD.get<const PointerToMemberData *>()->end();
216 }
217 
218 //===----------------------------------------------------------------------===//
219 // Useful predicates.
220 //===----------------------------------------------------------------------===//
221 
222 bool SVal::isConstant() const {
223  return getAs<nonloc::ConcreteInt>() || getAs<loc::ConcreteInt>();
224 }
225 
226 bool SVal::isConstant(int I) const {
227  if (Optional<loc::ConcreteInt> LV = getAs<loc::ConcreteInt>())
228  return LV->getValue() == I;
229  if (Optional<nonloc::ConcreteInt> NV = getAs<nonloc::ConcreteInt>())
230  return NV->getValue() == I;
231  return false;
232 }
233 
234 bool SVal::isZeroConstant() const {
235  return isConstant(0);
236 }
237 
238 //===----------------------------------------------------------------------===//
239 // Transfer function dispatch for Non-Locs.
240 //===----------------------------------------------------------------------===//
241 
244  const nonloc::ConcreteInt& R) const {
245  const llvm::APSInt* X =
246  svalBuilder.getBasicValueFactory().evalAPSInt(Op, getValue(), R.getValue());
247 
248  if (X)
249  return nonloc::ConcreteInt(*X);
250  else
251  return UndefinedVal();
252 }
253 
256  return svalBuilder.makeIntVal(~getValue());
257 }
258 
261  return svalBuilder.makeIntVal(-getValue());
262 }
263 
264 //===----------------------------------------------------------------------===//
265 // Transfer function dispatch for Locs.
266 //===----------------------------------------------------------------------===//
267 
270  const loc::ConcreteInt& R) const {
271  assert(BinaryOperator::isComparisonOp(Op) || Op == BO_Sub);
272 
273  const llvm::APSInt *X = BasicVals.evalAPSInt(Op, getValue(), R.getValue());
274 
275  if (X)
276  return nonloc::ConcreteInt(*X);
277  else
278  return UndefinedVal();
279 }
280 
281 //===----------------------------------------------------------------------===//
282 // Pretty-Printing.
283 //===----------------------------------------------------------------------===//
284 
285 LLVM_DUMP_METHOD void SVal::dump() const { dumpToStream(llvm::errs()); }
286 
287 void SVal::dumpToStream(raw_ostream &os) const {
288  switch (getBaseKind()) {
289  case UnknownValKind:
290  os << "Unknown";
291  break;
292  case NonLocKind:
293  castAs<NonLoc>().dumpToStream(os);
294  break;
295  case LocKind:
296  castAs<Loc>().dumpToStream(os);
297  break;
298  case UndefinedValKind:
299  os << "Undefined";
300  break;
301  }
302 }
303 
304 void NonLoc::dumpToStream(raw_ostream &os) const {
305  switch (getSubKind()) {
306  case nonloc::ConcreteIntKind: {
307  const auto &Value = castAs<nonloc::ConcreteInt>().getValue();
308  os << Value << ' ' << (Value.isSigned() ? 'S' : 'U')
309  << Value.getBitWidth() << 'b';
310  break;
311  }
312  case nonloc::SymbolValKind:
313  os << castAs<nonloc::SymbolVal>().getSymbol();
314  break;
315 
316  case nonloc::LocAsIntegerKind: {
317  const nonloc::LocAsInteger& C = castAs<nonloc::LocAsInteger>();
318  os << C.getLoc() << " [as " << C.getNumBits() << " bit integer]";
319  break;
320  }
321  case nonloc::CompoundValKind: {
322  const nonloc::CompoundVal& C = castAs<nonloc::CompoundVal>();
323  os << "compoundVal{";
324  bool first = true;
325  for (const auto &I : C) {
326  if (first) {
327  os << ' '; first = false;
328  }
329  else
330  os << ", ";
331 
332  I.dumpToStream(os);
333  }
334  os << "}";
335  break;
336  }
337  case nonloc::LazyCompoundValKind: {
338  const nonloc::LazyCompoundVal &C = castAs<nonloc::LazyCompoundVal>();
339  os << "lazyCompoundVal{" << const_cast<void *>(C.getStore())
340  << ',' << C.getRegion()
341  << '}';
342  break;
343  }
344  case nonloc::PointerToMemberKind: {
345  os << "pointerToMember{";
346  const nonloc::PointerToMember &CastRes =
347  castAs<nonloc::PointerToMember>();
348  if (CastRes.getDecl())
349  os << "|" << CastRes.getDecl()->getQualifiedNameAsString() << "|";
350  bool first = true;
351  for (const auto &I : CastRes) {
352  if (first) {
353  os << ' '; first = false;
354  }
355  else
356  os << ", ";
357 
358  os << (*I).getType().getAsString();
359  }
360 
361  os << '}';
362  break;
363  }
364  default:
365  assert(false && "Pretty-printed not implemented for this NonLoc.");
366  break;
367  }
368 }
369 
370 void Loc::dumpToStream(raw_ostream &os) const {
371  switch (getSubKind()) {
372  case loc::ConcreteIntKind:
373  os << castAs<loc::ConcreteInt>().getValue().getZExtValue() << " (Loc)";
374  break;
375  case loc::GotoLabelKind:
376  os << "&&" << castAs<loc::GotoLabel>().getLabel()->getName();
377  break;
378  case loc::MemRegionValKind:
379  os << '&' << castAs<loc::MemRegionVal>().getRegion()->getString();
380  break;
381  default:
382  llvm_unreachable("Pretty-printing not implemented for this Loc.");
383  }
384 }
Represents a function declaration or definition.
Definition: Decl.h:1738
TypedValueRegion - An abstract class representing regions having a typed value.
Definition: MemRegion.h:530
nonloc::ConcreteInt makeIntVal(const IntegerLiteral *integer)
Definition: SValBuilder.h:279
MemRegion - The root abstract class for all memory regions.
Definition: MemRegion.h:95
SymbolRef getLocSymbolInBase() const
Get the symbol in the SVal or its base region.
Definition: SVals.cpp:101
C Language Family Type Representation.
llvm::ImmutableList< const CXXBaseSpecifier * >::iterator iterator
Definition: SVals.h:542
Value representing integer constant.
Definition: SVals.h:377
const DeclaratorDecl * getDecl() const
Definition: SVals.cpp:178
SymbolRef getAsLocSymbol(bool IncludeBaseRegions=false) const
If this SVal is a location and wraps a symbol, return that SymbolRef.
Definition: SVals.cpp:85
Symbolic value.
Definition: SymExpr.h:30
const SymbolicRegion * getSymbolicBase() const
If this is a symbolic region, returns the region.
Definition: MemRegion.cpp:1217
void dumpToStream(raw_ostream &OS) const
Definition: SVals.cpp:287
ConcreteInt evalComplement(SValBuilder &svalBuilder) const
Definition: SVals.cpp:255
Value representing pointer-to-member.
Definition: SVals.h:522
llvm::ImmutableList< SVal >::iterator iterator
Definition: SVals.h:465
unsigned getNumBits() const
Definition: SVals.h:434
void dump() const
Definition: SVals.cpp:285
const SymExpr * getAsSymbolicExpression() const
getAsSymbolicExpression - If this Sval wraps a symbolic expression then return that expression...
Definition: SVals.cpp:137
BinaryOperatorKind
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
void dumpToStream(raw_ostream &Out) const
Definition: SVals.cpp:304
bool isConstant() const
Definition: SVals.cpp:222
const void * Data
Definition: SVals.h:87
void dumpToStream(raw_ostream &Out) const
Definition: SVals.cpp:370
SymbolRef getAsSymbol(bool IncludeBaseRegions=false) const
If this SVal wraps a symbol return that SymbolRef.
Definition: SVals.cpp:127
bool hasConjuredSymbol() const
hasConjuredSymbol - If this SVal wraps a conjured symbol, return true;
Definition: SVals.cpp:44
Represents a ValueDecl that came out of a declarator.
Definition: Decl.h:689
unsigned getSubKind() const
Definition: SVals.h:120
const RegionTy * getAs() const
Definition: MemRegion.h:1231
SymbolicRegion - A special, "non-concrete" region.
Definition: MemRegion.h:764
const MemRegion * stripCasts(bool StripBaseCasts=true) const
Get the underlining region and strip casts.
Definition: SVals.cpp:161
static SVal getValue(SVal val, SValBuilder &svalBuilder)
bool isComparisonOp() const
Definition: Expr.h:3383
FunctionCodeRegion - A region that represents code texts of function.
Definition: MemRegion.h:581
const MemRegion * getAsRegion() const
Definition: SVals.cpp:151
SVal - This represents a symbolic expression, which can be either an L-value or an R-value...
Definition: SVals.h:76
const llvm::APSInt * evalAPSInt(BinaryOperator::Opcode Op, const llvm::APSInt &V1, const llvm::APSInt &V2)
BaseKind getBaseKind() const
Definition: SVals.h:119
Dataflow Directional Tag Classes.
bool isZeroConstant() const
Definition: SVals.cpp:234
const void * getStore() const
Definition: SVals.cpp:166
SVal evalBinOp(BasicValueFactory &BasicVals, BinaryOperator::Opcode Op, const ConcreteInt &R) const
Definition: SVals.cpp:268
const MemRegion * StripCasts(bool StripBaseAndDerivedCasts=true) const
Definition: MemRegion.cpp:1194
const llvm::APSInt & getValue() const
Definition: SVals.h:642
const FunctionDecl * getAsFunctionDecl() const
getAsFunctionDecl - If this SVal is a MemRegionVal and wraps a CodeTextRegion wrapping a FunctionDecl...
Definition: SVals.cpp:63
BasicValueFactory & getBasicValueFactory()
Definition: SValBuilder.h:169
SVal evalBinOp(SValBuilder &svalBuilder, BinaryOperator::Opcode Op, const ConcreteInt &R) const
Definition: SVals.cpp:242
llvm::PointerUnion< const DeclaratorDecl *, const PointerToMemberData * > PTMDataType
Definition: SVals.h:527
const SymExpr * getAsSymExpr() const
Definition: SVals.cpp:144
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:13954
Defines the C++ Decl subclasses, other than those for templates (found in DeclTemplate.h) and friends (in DeclFriend.h).
const TypedValueRegion * getRegion() const
Definition: SVals.cpp:170
std::string getQualifiedNameAsString() const
Definition: Decl.cpp:1520
ConcreteInt evalMinus(SValBuilder &svalBuilder) const
Definition: SVals.cpp:260
const llvm::APSInt & getValue() const
Definition: SVals.h:381