clang  7.0.0svn
SVals.cpp
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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();
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  const auto PTMD = this->getPTMData();
176  if (PTMD.isNull())
177  return nullptr;
178 
179  const DeclaratorDecl *DD = nullptr;
180  if (PTMD.is<const DeclaratorDecl *>())
181  DD = PTMD.get<const DeclaratorDecl *>();
182  else
183  DD = PTMD.get<const PointerToMemberData *>()->getDeclaratorDecl();
184 
185  return DD;
186 }
187 
188 //===----------------------------------------------------------------------===//
189 // Other Iterators.
190 //===----------------------------------------------------------------------===//
191 
193  return getValue()->begin();
194 }
195 
197  return getValue()->end();
198 }
199 
201  const PTMDataType PTMD = getPTMData();
202  if (PTMD.is<const DeclaratorDecl *>())
203  return {};
204  return PTMD.get<const PointerToMemberData *>()->begin();
205 }
206 
208  const PTMDataType PTMD = getPTMData();
209  if (PTMD.is<const DeclaratorDecl *>())
210  return {};
211  return PTMD.get<const PointerToMemberData *>()->end();
212 }
213 
214 //===----------------------------------------------------------------------===//
215 // Useful predicates.
216 //===----------------------------------------------------------------------===//
217 
218 bool SVal::isConstant() const {
219  return getAs<nonloc::ConcreteInt>() || getAs<loc::ConcreteInt>();
220 }
221 
222 bool SVal::isConstant(int I) const {
223  if (Optional<loc::ConcreteInt> LV = getAs<loc::ConcreteInt>())
224  return LV->getValue() == I;
225  if (Optional<nonloc::ConcreteInt> NV = getAs<nonloc::ConcreteInt>())
226  return NV->getValue() == I;
227  return false;
228 }
229 
230 bool SVal::isZeroConstant() const {
231  return isConstant(0);
232 }
233 
234 //===----------------------------------------------------------------------===//
235 // Transfer function dispatch for Non-Locs.
236 //===----------------------------------------------------------------------===//
237 
240  const nonloc::ConcreteInt& R) const {
241  const llvm::APSInt* X =
242  svalBuilder.getBasicValueFactory().evalAPSInt(Op, getValue(), R.getValue());
243 
244  if (X)
245  return nonloc::ConcreteInt(*X);
246  else
247  return UndefinedVal();
248 }
249 
252  return svalBuilder.makeIntVal(~getValue());
253 }
254 
257  return svalBuilder.makeIntVal(-getValue());
258 }
259 
260 //===----------------------------------------------------------------------===//
261 // Transfer function dispatch for Locs.
262 //===----------------------------------------------------------------------===//
263 
266  const loc::ConcreteInt& R) const {
267  assert(BinaryOperator::isComparisonOp(Op) || Op == BO_Sub);
268 
269  const llvm::APSInt *X = BasicVals.evalAPSInt(Op, getValue(), R.getValue());
270 
271  if (X)
272  return nonloc::ConcreteInt(*X);
273  else
274  return UndefinedVal();
275 }
276 
277 //===----------------------------------------------------------------------===//
278 // Pretty-Printing.
279 //===----------------------------------------------------------------------===//
280 
281 LLVM_DUMP_METHOD void SVal::dump() const { dumpToStream(llvm::errs()); }
282 
283 void SVal::dumpToStream(raw_ostream &os) const {
284  switch (getBaseKind()) {
285  case UnknownValKind:
286  os << "Unknown";
287  break;
288  case NonLocKind:
289  castAs<NonLoc>().dumpToStream(os);
290  break;
291  case LocKind:
292  castAs<Loc>().dumpToStream(os);
293  break;
294  case UndefinedValKind:
295  os << "Undefined";
296  break;
297  }
298 }
299 
300 void NonLoc::dumpToStream(raw_ostream &os) const {
301  switch (getSubKind()) {
302  case nonloc::ConcreteIntKind: {
303  const auto &Value = castAs<nonloc::ConcreteInt>().getValue();
304  os << Value << ' ' << (Value.isSigned() ? 'S' : 'U')
305  << Value.getBitWidth() << 'b';
306  break;
307  }
308  case nonloc::SymbolValKind:
309  os << castAs<nonloc::SymbolVal>().getSymbol();
310  break;
311 
312  case nonloc::LocAsIntegerKind: {
313  const nonloc::LocAsInteger& C = castAs<nonloc::LocAsInteger>();
314  os << C.getLoc() << " [as " << C.getNumBits() << " bit integer]";
315  break;
316  }
317  case nonloc::CompoundValKind: {
318  const nonloc::CompoundVal& C = castAs<nonloc::CompoundVal>();
319  os << "compoundVal{";
320  bool first = true;
321  for (const auto &I : C) {
322  if (first) {
323  os << ' '; first = false;
324  }
325  else
326  os << ", ";
327 
328  I.dumpToStream(os);
329  }
330  os << "}";
331  break;
332  }
333  case nonloc::LazyCompoundValKind: {
334  const nonloc::LazyCompoundVal &C = castAs<nonloc::LazyCompoundVal>();
335  os << "lazyCompoundVal{" << const_cast<void *>(C.getStore())
336  << ',' << C.getRegion()
337  << '}';
338  break;
339  }
340  case nonloc::PointerToMemberKind: {
341  os << "pointerToMember{";
342  const nonloc::PointerToMember &CastRes =
343  castAs<nonloc::PointerToMember>();
344  if (CastRes.getDecl())
345  os << "|" << CastRes.getDecl()->getQualifiedNameAsString() << "|";
346  bool first = true;
347  for (const auto &I : CastRes) {
348  if (first) {
349  os << ' '; first = false;
350  }
351  else
352  os << ", ";
353 
354  os << (*I).getType().getAsString();
355  }
356 
357  os << '}';
358  break;
359  }
360  default:
361  assert(false && "Pretty-printed not implemented for this NonLoc.");
362  break;
363  }
364 }
365 
366 void Loc::dumpToStream(raw_ostream &os) const {
367  switch (getSubKind()) {
368  case loc::ConcreteIntKind:
369  os << castAs<loc::ConcreteInt>().getValue().getZExtValue() << " (Loc)";
370  break;
371  case loc::GotoLabelKind:
372  os << "&&" << castAs<loc::GotoLabel>().getLabel()->getName();
373  break;
374  case loc::MemRegionValKind:
375  os << '&' << castAs<loc::MemRegionVal>().getRegion()->getString();
376  break;
377  default:
378  llvm_unreachable("Pretty-printing not implemented for this Loc.");
379  }
380 }
Represents a function declaration or definition.
Definition: Decl.h:1714
TypedValueRegion - An abstract class representing regions having a typed value.
Definition: MemRegion.h:525
nonloc::ConcreteInt makeIntVal(const IntegerLiteral *integer)
Definition: SValBuilder.h:279
MemRegion - The root abstract class for all memory regions.
Definition: MemRegion.h:94
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:541
Value representing integer constant.
Definition: SVals.h:374
const DeclaratorDecl * getDecl() const
Definition: SVals.cpp:174
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:1173
void dumpToStream(raw_ostream &OS) const
Definition: SVals.cpp:283
ConcreteInt evalComplement(SValBuilder &svalBuilder) const
Definition: SVals.cpp:251
Value representing pointer-to-member.
Definition: SVals.h:519
llvm::ImmutableList< SVal >::iterator iterator
Definition: SVals.h:462
unsigned getNumBits() const
Definition: SVals.h:431
void dump() const
Definition: SVals.cpp:281
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:300
bool isConstant() const
Definition: SVals.cpp:218
const void * Data
Definition: SVals.h:87
void dumpToStream(raw_ostream &Out) const
Definition: SVals.cpp:366
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:688
unsigned getSubKind() const
Definition: SVals.h:120
const RegionTy * getAs() const
Definition: MemRegion.h:1180
SymbolicRegion - A special, "non-concrete" region.
Definition: MemRegion.h:759
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:3107
const MemRegion * StripCasts(bool StripBaseCasts=true) const
Definition: MemRegion.cpp:1151
FunctionCodeRegion - A region that represents code texts of function.
Definition: MemRegion.h:576
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:230
const void * getStore() const
Definition: SVals.cpp:166
SVal evalBinOp(BasicValueFactory &BasicVals, BinaryOperator::Opcode Op, const ConcreteInt &R) const
Definition: SVals.cpp:264
const llvm::APSInt & getValue() const
Definition: SVals.h:641
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:238
llvm::PointerUnion< const DeclaratorDecl *, const PointerToMemberData * > PTMDataType
Definition: SVals.h:524
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:13503
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:1500
ConcreteInt evalMinus(SValBuilder &svalBuilder) const
Definition: SVals.cpp:256
const llvm::APSInt & getValue() const
Definition: SVals.h:378