1 //== CheckerContext.h - Context info for path-sensitive checkers--*- 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 CheckerContext that provides contextual info for 11 // path-sensitive checkers. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_CHECKERCONTEXT_H 16 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_CHECKERCONTEXT_H 17 18 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h" 19 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 20 21 namespace clang { 22 namespace ento { 23 24 /// Declares an immutable map of type \p NameTy, suitable for placement into 25 /// the ProgramState. This is implementing using llvm::ImmutableMap. 26 /// 27 /// \code 28 /// State = State->set<Name>(K, V); 29 /// const Value *V = State->get<Name>(K); // Returns NULL if not in the map. 30 /// State = State->remove<Name>(K); 31 /// NameTy Map = State->get<Name>(); 32 /// \endcode 33 /// 34 /// The macro should not be used inside namespaces, or for traits that must 35 /// be accessible from more than one translation unit. 36 #define REGISTER_MAP_WITH_PROGRAMSTATE(Name, Key, Value) \ 37 REGISTER_TRAIT_WITH_PROGRAMSTATE(Name, \ 38 CLANG_ENTO_PROGRAMSTATE_MAP(Key, Value)) 39 40 /// Declares an immutable set of type \p NameTy, suitable for placement into 41 /// the ProgramState. This is implementing using llvm::ImmutableSet. 42 /// 43 /// \code 44 /// State = State->add<Name>(E); 45 /// State = State->remove<Name>(E); 46 /// bool Present = State->contains<Name>(E); 47 /// NameTy Set = State->get<Name>(); 48 /// \endcode 49 /// 50 /// The macro should not be used inside namespaces, or for traits that must 51 /// be accessible from more than one translation unit. 52 #define REGISTER_SET_WITH_PROGRAMSTATE(Name, Elem) \ 53 REGISTER_TRAIT_WITH_PROGRAMSTATE(Name, llvm::ImmutableSet<Elem>) 54 55 /// Declares an immutable list of type \p NameTy, suitable for placement into 56 /// the ProgramState. This is implementing using llvm::ImmutableList. 57 /// 58 /// \code 59 /// State = State->add<Name>(E); // Adds to the /end/ of the list. 60 /// bool Present = State->contains<Name>(E); 61 /// NameTy List = State->get<Name>(); 62 /// \endcode 63 /// 64 /// The macro should not be used inside namespaces, or for traits that must 65 /// be accessible from more than one translation unit. 66 #define REGISTER_LIST_WITH_PROGRAMSTATE(Name, Elem) \ 67 REGISTER_TRAIT_WITH_PROGRAMSTATE(Name, llvm::ImmutableList<Elem>) 68 69 70 class CheckerContext { 71 ExprEngine &Eng; 72 /// The current exploded(symbolic execution) graph node. 73 ExplodedNode *Pred; 74 /// The flag is true if the (state of the execution) has been modified 75 /// by the checker using this context. For example, a new transition has been 76 /// added or a bug report issued. 77 bool Changed; 78 /// The tagged location, which is used to generate all new nodes. 79 const ProgramPoint Location; 80 NodeBuilder &NB; 81 82 public: 83 /// If we are post visiting a call, this flag will be set if the 84 /// call was inlined. In all other cases it will be false. 85 const bool wasInlined; 86 87 CheckerContext(NodeBuilder &builder, 88 ExprEngine &eng, 89 ExplodedNode *pred, 90 const ProgramPoint &loc, 91 bool wasInlined = false) 92 : Eng(eng), 93 Pred(pred), 94 Changed(false), 95 Location(loc), 96 NB(builder), 97 wasInlined(wasInlined) { 98 assert(Pred->getState() && 99 "We should not call the checkers on an empty state."); 100 } 101 102 AnalysisManager &getAnalysisManager() { 103 return Eng.getAnalysisManager(); 104 } 105 106 ConstraintManager &getConstraintManager() { 107 return Eng.getConstraintManager(); 108 } 109 110 StoreManager &getStoreManager() { 111 return Eng.getStoreManager(); 112 } 113 114 /// \brief Returns the previous node in the exploded graph, which includes 115 /// the state of the program before the checker ran. Note, checkers should 116 /// not retain the node in their state since the nodes might get invalidated. 117 ExplodedNode *getPredecessor() { return Pred; } 118 const ProgramStateRef &getState() const { return Pred->getState(); } 119 120 /// \brief Check if the checker changed the state of the execution; ex: added 121 /// a new transition or a bug report. 122 bool isDifferent() { return Changed; } 123 124 /// \brief Returns the number of times the current block has been visited 125 /// along the analyzed path. 126 unsigned blockCount() const { 127 return NB.getContext().blockCount(); 128 } 129 130 ASTContext &getASTContext() { 131 return Eng.getContext(); 132 } 133 134 const LangOptions &getLangOpts() const { 135 return Eng.getContext().getLangOpts(); 136 } 137 138 const LocationContext *getLocationContext() const { 139 return Pred->getLocationContext(); 140 } 141 142 const StackFrameContext *getStackFrame() const { 143 return Pred->getStackFrame(); 144 } 145 146 /// Return true if the current LocationContext has no caller context. 147 bool inTopFrame() const { return getLocationContext()->inTopFrame(); } 148 149 BugReporter &getBugReporter() { 150 return Eng.getBugReporter(); 151 } 152 153 SourceManager &getSourceManager() { 154 return getBugReporter().getSourceManager(); 155 } 156 157 SValBuilder &getSValBuilder() { 158 return Eng.getSValBuilder(); 159 } 160 161 SymbolManager &getSymbolManager() { 162 return getSValBuilder().getSymbolManager(); 163 } 164 165 bool isObjCGCEnabled() const { 166 return Eng.isObjCGCEnabled(); 167 } 168 169 ProgramStateManager &getStateManager() { 170 return Eng.getStateManager(); 171 } 172 173 AnalysisDeclContext *getCurrentAnalysisDeclContext() const { 174 return Pred->getLocationContext()->getAnalysisDeclContext(); 175 } 176 177 /// \brief Get the blockID. 178 unsigned getBlockID() const { 179 return NB.getContext().getBlock()->getBlockID(); 180 } 181 182 /// \brief If the given node corresponds to a PostStore program point, 183 /// retrieve the location region as it was uttered in the code. 184 /// 185 /// This utility can be useful for generating extensive diagnostics, for 186 /// example, for finding variables that the given symbol was assigned to. 187 static const MemRegion *getLocationRegionIfPostStore(const ExplodedNode *N) { 188 ProgramPoint L = N->getLocation(); 189 if (Optional<PostStore> PSL = L.getAs<PostStore>()) 190 return reinterpret_cast<const MemRegion*>(PSL->getLocationValue()); 191 return nullptr; 192 } 193 194 /// \brief Get the value of arbitrary expressions at this point in the path. 195 SVal getSVal(const Stmt *S) const { 196 return getState()->getSVal(S, getLocationContext()); 197 } 198 199 /// \brief Returns true if the value of \p E is greater than or equal to \p 200 /// Val under unsigned comparison 201 bool isGreaterOrEqual(const Expr *E, unsigned long long Val); 202 203 /// Returns true if the value of \p E is negative. 204 bool isNegative(const Expr *E); 205 206 /// \brief Generates a new transition in the program state graph 207 /// (ExplodedGraph). Uses the default CheckerContext predecessor node. 208 /// 209 /// @param State The state of the generated node. If not specified, the state 210 /// will not be changed, but the new node will have the checker's tag. 211 /// @param Tag The tag is used to uniquely identify the creation site. If no 212 /// tag is specified, a default tag, unique to the given checker, 213 /// will be used. Tags are used to prevent states generated at 214 /// different sites from caching out. 215 ExplodedNode *addTransition(ProgramStateRef State = nullptr, 216 const ProgramPointTag *Tag = nullptr) { 217 return addTransitionImpl(State ? State : getState(), false, nullptr, Tag); 218 } 219 220 /// \brief Generates a new transition with the given predecessor. 221 /// Allows checkers to generate a chain of nodes. 222 /// 223 /// @param State The state of the generated node. 224 /// @param Pred The transition will be generated from the specified Pred node 225 /// to the newly generated node. 226 /// @param Tag The tag to uniquely identify the creation site. 227 ExplodedNode *addTransition(ProgramStateRef State, 228 ExplodedNode *Pred, 229 const ProgramPointTag *Tag = nullptr) { 230 return addTransitionImpl(State, false, Pred, Tag); 231 } 232 233 /// \brief Generate a sink node. Generating a sink stops exploration of the 234 /// given path. To create a sink node for the purpose of reporting an error, 235 /// checkers should use generateErrorNode() instead. 236 ExplodedNode *generateSink(ProgramStateRef State, ExplodedNode *Pred, 237 const ProgramPointTag *Tag = nullptr) { 238 return addTransitionImpl(State ? State : getState(), true, Pred, Tag); 239 } 240 241 /// \brief Generate a transition to a node that will be used to report 242 /// an error. This node will be a sink. That is, it will stop exploration of 243 /// the given path. 244 /// 245 /// @param State The state of the generated node. 246 /// @param Tag The tag to uniquely identify the creation site. If null, 247 /// the default tag for the checker will be used. 248 ExplodedNode *generateErrorNode(ProgramStateRef State = nullptr, 249 const ProgramPointTag *Tag = nullptr) { 250 return generateSink(State, Pred, 251 (Tag ? Tag : Location.getTag())); 252 } 253 254 /// \brief Generate a transition to a node that will be used to report 255 /// an error. This node will not be a sink. That is, exploration will 256 /// continue along this path. 257 /// 258 /// @param State The state of the generated node. 259 /// @param Tag The tag to uniquely identify the creation site. If null, 260 /// the default tag for the checker will be used. 261 ExplodedNode * 262 generateNonFatalErrorNode(ProgramStateRef State = nullptr, 263 const ProgramPointTag *Tag = nullptr) { 264 return addTransition(State, (Tag ? Tag : Location.getTag())); 265 } 266 267 /// \brief Emit the diagnostics report. 268 void emitReport(std::unique_ptr<BugReport> R) { 269 Changed = true; 270 Eng.getBugReporter().emitReport(std::move(R)); 271 } 272 273 /// \brief Returns the word that should be used to refer to the declaration 274 /// in the report. 275 StringRef getDeclDescription(const Decl *D); 276 277 /// \brief Get the declaration of the called function (path-sensitive). 278 const FunctionDecl *getCalleeDecl(const CallExpr *CE) const; 279 280 /// \brief Get the name of the called function (path-sensitive). 281 StringRef getCalleeName(const FunctionDecl *FunDecl) const; 282 283 /// \brief Get the identifier of the called function (path-sensitive). 284 const IdentifierInfo *getCalleeIdentifier(const CallExpr *CE) const { 285 const FunctionDecl *FunDecl = getCalleeDecl(CE); 286 if (FunDecl) 287 return FunDecl->getIdentifier(); 288 else 289 return nullptr; 290 } 291 292 /// \brief Get the name of the called function (path-sensitive). 293 StringRef getCalleeName(const CallExpr *CE) const { 294 const FunctionDecl *FunDecl = getCalleeDecl(CE); 295 return getCalleeName(FunDecl); 296 } 297 298 /// \brief Returns true if the callee is an externally-visible function in the 299 /// top-level namespace, such as \c malloc. 300 /// 301 /// If a name is provided, the function must additionally match the given 302 /// name. 303 /// 304 /// Note that this deliberately excludes C++ library functions in the \c std 305 /// namespace, but will include C library functions accessed through the 306 /// \c std namespace. This also does not check if the function is declared 307 /// as 'extern "C"', or if it uses C++ name mangling. 308 static bool isCLibraryFunction(const FunctionDecl *FD, 309 StringRef Name = StringRef()); 310 311 /// \brief Depending on wither the location corresponds to a macro, return 312 /// either the macro name or the token spelling. 313 /// 314 /// This could be useful when checkers' logic depends on whether a function 315 /// is called with a given macro argument. For example: 316 /// s = socket(AF_INET,..) 317 /// If AF_INET is a macro, the result should be treated as a source of taint. 318 /// 319 /// \sa clang::Lexer::getSpelling(), clang::Lexer::getImmediateMacroName(). 320 StringRef getMacroNameOrSpelling(SourceLocation &Loc); 321 322 private: 323 ExplodedNode *addTransitionImpl(ProgramStateRef State, 324 bool MarkAsSink, 325 ExplodedNode *P = nullptr, 326 const ProgramPointTag *Tag = nullptr) { 327 // The analyzer may stop exploring if it sees a state it has previously 328 // visited ("cache out"). The early return here is a defensive check to 329 // prevent accidental caching out by checker API clients. Unless there is a 330 // tag or the client checker has requested that the generated node be 331 // marked as a sink, we assume that a client requesting a transition to a 332 // state that is the same as the predecessor state has made a mistake. We 333 // return the predecessor rather than cache out. 334 // 335 // TODO: We could potentially change the return to an assertion to alert 336 // clients to their mistake, but several checkers (including 337 // DereferenceChecker, CallAndMessageChecker, and DynamicTypePropagation) 338 // rely upon the defensive behavior and would need to be updated. 339 if (!State || (State == Pred->getState() && !Tag && !MarkAsSink)) 340 return Pred; 341 342 Changed = true; 343 const ProgramPoint &LocalLoc = (Tag ? Location.withTag(Tag) : Location); 344 if (!P) 345 P = Pred; 346 347 ExplodedNode *node; 348 if (MarkAsSink) 349 node = NB.generateSink(LocalLoc, State, P); 350 else 351 node = NB.generateNode(LocalLoc, State, P); 352 return node; 353 } 354 }; 355 356 } // end GR namespace 357 358 } // end clang namespace 359 360 #endif 361