ExprEngineCXX.cpp revision 10f77ad7fc5e5cf3f37a9b14ff5843468b8b84d2
1//===- ExprEngineCXX.cpp - ExprEngine support for C++ -----------*- 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 the C++ expression evaluation engine. 11// 12//===----------------------------------------------------------------------===// 13 14#include "clang/StaticAnalyzer/Core/CheckerManager.h" 15#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h" 16#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h" 17#include "clang/StaticAnalyzer/Core/PathSensitive/ObjCMessage.h" 18#include "clang/AST/DeclCXX.h" 19#include "clang/AST/StmtCXX.h" 20 21using namespace clang; 22using namespace ento; 23 24void ExprEngine::CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME, 25 ExplodedNode *Pred, 26 ExplodedNodeSet &Dst) { 27 StmtNodeBuilder Bldr(Pred, Dst, *currentBuilderContext); 28 const Expr *tempExpr = ME->GetTemporaryExpr()->IgnoreParens(); 29 ProgramStateRef state = Pred->getState(); 30 const LocationContext *LCtx = Pred->getLocationContext(); 31 32 // Bind the temporary object to the value of the expression. Then bind 33 // the expression to the location of the object. 34 SVal V = state->getSVal(tempExpr, Pred->getLocationContext()); 35 36 const MemRegion *R = 37 svalBuilder.getRegionManager().getCXXTempObjectRegion(ME, LCtx); 38 39 state = state->bindLoc(loc::MemRegionVal(R), V); 40 Bldr.generateNode(ME, Pred, state->BindExpr(ME, LCtx, loc::MemRegionVal(R))); 41} 42 43void ExprEngine::VisitCXXTemporaryObjectExpr(const CXXTemporaryObjectExpr *expr, 44 ExplodedNode *Pred, 45 ExplodedNodeSet &Dst) { 46 VisitCXXConstructExpr(expr, 0, Pred, Dst); 47} 48 49void ExprEngine::VisitCXXConstructExpr(const CXXConstructExpr *E, 50 const MemRegion *Dest, 51 ExplodedNode *Pred, 52 ExplodedNodeSet &destNodes) { 53 54#if 0 55 const CXXConstructorDecl *CD = E->getConstructor(); 56 assert(CD); 57#endif 58 59#if 0 60 if (!(CD->doesThisDeclarationHaveABody() && AMgr.shouldInlineCall())) 61 // FIXME: invalidate the object. 62 return; 63#endif 64 65#if 0 66 // Is the constructor elidable? 67 if (E->isElidable()) { 68 destNodes.Add(Pred); 69 return; 70 } 71#endif 72 73 // Perform the previsit of the constructor. 74 ExplodedNodeSet SrcNodes; 75 SrcNodes.Add(Pred); 76 ExplodedNodeSet TmpNodes; 77 getCheckerManager().runCheckersForPreStmt(TmpNodes, SrcNodes, E, *this); 78 79 // Evaluate the constructor. Currently we don't now allow checker-specific 80 // implementations of specific constructors (as we do with ordinary 81 // function calls. We can re-evaluate this in the future. 82 83#if 0 84 // Inlining currently isn't fully implemented. 85 86 if (AMgr.shouldInlineCall()) { 87 if (!Dest) 88 Dest = 89 svalBuilder.getRegionManager().getCXXTempObjectRegion(E, 90 Pred->getLocationContext()); 91 92 // The callee stack frame context used to create the 'this' 93 // parameter region. 94 const StackFrameContext *SFC = 95 AMgr.getStackFrame(CD, Pred->getLocationContext(), 96 E, currentBuilderContext->getBlock(), 97 currentStmtIdx); 98 99 // Create the 'this' region. 100 const CXXThisRegion *ThisR = 101 getCXXThisRegion(E->getConstructor()->getParent(), SFC); 102 103 CallEnter Loc(E, SFC, Pred->getLocationContext()); 104 105 StmtNodeBuilder Bldr(SrcNodes, TmpNodes, *currentBuilderContext); 106 for (ExplodedNodeSet::iterator NI = SrcNodes.begin(), 107 NE = SrcNodes.end(); NI != NE; ++NI) { 108 ProgramStateRef state = (*NI)->getState(); 109 // Setup 'this' region, so that the ctor is evaluated on the object pointed 110 // by 'Dest'. 111 state = state->bindLoc(loc::MemRegionVal(ThisR), loc::MemRegionVal(Dest)); 112 Bldr.generateNode(Loc, *NI, state); 113 } 114 } 115#endif 116 117 // Default semantics: invalidate all regions passed as arguments. 118 ExplodedNodeSet destCall; 119 { 120 StmtNodeBuilder Bldr(TmpNodes, destCall, *currentBuilderContext); 121 for (ExplodedNodeSet::iterator i = TmpNodes.begin(), e = TmpNodes.end(); 122 i != e; ++i) 123 { 124 ExplodedNode *Pred = *i; 125 const LocationContext *LC = Pred->getLocationContext(); 126 ProgramStateRef state = Pred->getState(); 127 128 state = invalidateArguments(state, CallOrObjCMessage(E, state, LC), LC); 129 Bldr.generateNode(E, Pred, state); 130 } 131 } 132 // Do the post visit. 133 getCheckerManager().runCheckersForPostStmt(destNodes, destCall, E, *this); 134} 135 136void ExprEngine::VisitCXXDestructor(const CXXDestructorDecl *DD, 137 const MemRegion *Dest, 138 const Stmt *S, 139 ExplodedNode *Pred, 140 ExplodedNodeSet &Dst) { 141 StmtNodeBuilder Bldr(Pred, Dst, *currentBuilderContext); 142 if (!(DD->doesThisDeclarationHaveABody() && AMgr.shouldInlineCall())) 143 return; 144 145 // Create the context for 'this' region. 146 const StackFrameContext *SFC = 147 AnalysisDeclContexts.getContext(DD)-> 148 getStackFrame(Pred->getLocationContext(), S, 149 currentBuilderContext->getBlock(), currentStmtIdx); 150 151 CallEnter PP(S, SFC, Pred->getLocationContext()); 152 ProgramStateRef state = Pred->getState(); 153 state = state->bindLoc(svalBuilder.getCXXThis(DD->getParent(), SFC), 154 loc::MemRegionVal(Dest)); 155 Bldr.generateNode(PP, Pred, state); 156} 157 158static bool isPointerToConst(const ParmVarDecl *ParamDecl) { 159 // FIXME: Copied from ExprEngineCallAndReturn.cpp 160 QualType PointeeTy = ParamDecl->getOriginalType()->getPointeeType(); 161 if (PointeeTy != QualType() && PointeeTy.isConstQualified() && 162 !PointeeTy->isAnyPointerType() && !PointeeTy->isReferenceType()) { 163 return true; 164 } 165 return false; 166} 167 168void ExprEngine::VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred, 169 ExplodedNodeSet &Dst) { 170 StmtNodeBuilder Bldr(Pred, Dst, *currentBuilderContext); 171 172 unsigned blockCount = currentBuilderContext->getCurrentBlockCount(); 173 const LocationContext *LCtx = Pred->getLocationContext(); 174 DefinedOrUnknownSVal symVal = 175 svalBuilder.getConjuredSymbolVal(NULL, CNE, LCtx, CNE->getType(), blockCount); 176 const MemRegion *NewReg = cast<loc::MemRegionVal>(symVal).getRegion(); 177 QualType ObjTy = CNE->getType()->getAs<PointerType>()->getPointeeType(); 178 const ElementRegion *EleReg = 179 getStoreManager().GetElementZeroRegion(NewReg, ObjTy); 180 ProgramStateRef State = Pred->getState(); 181 182 if (CNE->isArray()) { 183 // FIXME: allocating an array requires simulating the constructors. 184 // For now, just return a symbolicated region. 185 State = State->BindExpr(CNE, Pred->getLocationContext(), 186 loc::MemRegionVal(EleReg)); 187 Bldr.generateNode(CNE, Pred, State); 188 return; 189 } 190 191 FunctionDecl *FD = CNE->getOperatorNew(); 192 if (FD && FD->isReservedGlobalPlacementOperator()) { 193 // Non-array placement new should always return the placement location. 194 SVal PlacementLoc = State->getSVal(CNE->getPlacementArg(0), LCtx); 195 State = State->BindExpr(CNE, LCtx, PlacementLoc); 196 // FIXME: Once we have proper support for CXXConstructExprs inside 197 // CXXNewExpr, we need to make sure that the constructed object is not 198 // immediately invalidated here. (The placement call should happen before 199 // the constructor call anyway.) 200 } 201 202 // Invalidate placement args. 203 204 // FIXME: This is largely copied from invalidateArguments, because 205 // CallOrObjCMessage is not general enough to handle new-expressions yet. 206 SmallVector<const MemRegion *, 4> RegionsToInvalidate; 207 208 unsigned Index = 0; 209 for (CXXNewExpr::const_arg_iterator I = CNE->placement_arg_begin(), 210 E = CNE->placement_arg_end(); 211 I != E; ++I) { 212 // Pre-increment the argument index to skip over the implicit size arg. 213 ++Index; 214 if (FD && Index < FD->getNumParams()) 215 if (isPointerToConst(FD->getParamDecl(Index))) 216 continue; 217 218 SVal V = State->getSVal(*I, LCtx); 219 220 // If we are passing a location wrapped as an integer, unwrap it and 221 // invalidate the values referred by the location. 222 if (nonloc::LocAsInteger *Wrapped = dyn_cast<nonloc::LocAsInteger>(&V)) 223 V = Wrapped->getLoc(); 224 else if (!isa<Loc>(V)) 225 continue; 226 227 if (const MemRegion *R = V.getAsRegion()) { 228 // Invalidate the value of the variable passed by reference. 229 230 // Are we dealing with an ElementRegion? If the element type is 231 // a basic integer type (e.g., char, int) and the underlying region 232 // is a variable region then strip off the ElementRegion. 233 // FIXME: We really need to think about this for the general case 234 // as sometimes we are reasoning about arrays and other times 235 // about (char*), etc., is just a form of passing raw bytes. 236 // e.g., void *p = alloca(); foo((char*)p); 237 if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) { 238 // Checking for 'integral type' is probably too promiscuous, but 239 // we'll leave it in for now until we have a systematic way of 240 // handling all of these cases. Eventually we need to come up 241 // with an interface to StoreManager so that this logic can be 242 // appropriately delegated to the respective StoreManagers while 243 // still allowing us to do checker-specific logic (e.g., 244 // invalidating reference counts), probably via callbacks. 245 if (ER->getElementType()->isIntegralOrEnumerationType()) { 246 const MemRegion *superReg = ER->getSuperRegion(); 247 if (isa<VarRegion>(superReg) || isa<FieldRegion>(superReg) || 248 isa<ObjCIvarRegion>(superReg)) 249 R = cast<TypedRegion>(superReg); 250 } 251 // FIXME: What about layers of ElementRegions? 252 } 253 254 // Mark this region for invalidation. We batch invalidate regions 255 // below for efficiency. 256 RegionsToInvalidate.push_back(R); 257 } else { 258 // Nuke all other arguments passed by reference. 259 // FIXME: is this necessary or correct? This handles the non-Region 260 // cases. Is it ever valid to store to these? 261 State = State->unbindLoc(cast<Loc>(V)); 262 } 263 } 264 265 // Invalidate designated regions using the batch invalidation API. 266 267 // FIXME: We can have collisions on the conjured symbol if the 268 // expression *I also creates conjured symbols. We probably want 269 // to identify conjured symbols by an expression pair: the enclosing 270 // expression (the context) and the expression itself. This should 271 // disambiguate conjured symbols. 272 unsigned Count = currentBuilderContext->getCurrentBlockCount(); 273 274 // NOTE: Even if RegionsToInvalidate is empty, we may still invalidate 275 // global variables. 276 State = State->invalidateRegions(RegionsToInvalidate, CNE, Count, LCtx); 277 Bldr.generateNode(CNE, Pred, State); 278 return; 279 280 // FIXME: The below code is long-since dead. However, constructor handling 281 // in new-expressions is far from complete. See PR12014 for more details. 282#if 0 283 // Evaluate constructor arguments. 284 const FunctionProtoType *FnType = NULL; 285 const CXXConstructorDecl *CD = CNE->getConstructor(); 286 if (CD) 287 FnType = CD->getType()->getAs<FunctionProtoType>(); 288 ExplodedNodeSet argsEvaluated; 289 Bldr.takeNodes(Pred); 290 evalArguments(CNE->constructor_arg_begin(), CNE->constructor_arg_end(), 291 FnType, Pred, argsEvaluated); 292 Bldr.addNodes(argsEvaluated); 293 294 // Initialize the object region and bind the 'new' expression. 295 for (ExplodedNodeSet::iterator I = argsEvaluated.begin(), 296 E = argsEvaluated.end(); I != E; ++I) { 297 298 ProgramStateRef state = (*I)->getState(); 299 300 // Accumulate list of regions that are invalidated. 301 // FIXME: Eventually we should unify the logic for constructor 302 // processing in one place. 303 SmallVector<const MemRegion*, 10> regionsToInvalidate; 304 for (CXXNewExpr::const_arg_iterator 305 ai = CNE->constructor_arg_begin(), ae = CNE->constructor_arg_end(); 306 ai != ae; ++ai) 307 { 308 SVal val = state->getSVal(*ai, (*I)->getLocationContext()); 309 if (const MemRegion *region = val.getAsRegion()) 310 regionsToInvalidate.push_back(region); 311 } 312 313 if (ObjTy->isRecordType()) { 314 regionsToInvalidate.push_back(EleReg); 315 // Invalidate the regions. 316 // TODO: Pass the call to new information as the last argument, to limit 317 // the globals which will get invalidated. 318 state = state->invalidateRegions(regionsToInvalidate, 319 CNE, blockCount, 0, 0); 320 321 } else { 322 // Invalidate the regions. 323 // TODO: Pass the call to new information as the last argument, to limit 324 // the globals which will get invalidated. 325 state = state->invalidateRegions(regionsToInvalidate, 326 CNE, blockCount, 0, 0); 327 328 if (CNE->hasInitializer()) { 329 SVal V = state->getSVal(*CNE->constructor_arg_begin(), 330 (*I)->getLocationContext()); 331 state = state->bindLoc(loc::MemRegionVal(EleReg), V); 332 } else { 333 // Explicitly set to undefined, because currently we retrieve symbolic 334 // value from symbolic region. 335 state = state->bindLoc(loc::MemRegionVal(EleReg), UndefinedVal()); 336 } 337 } 338 state = state->BindExpr(CNE, (*I)->getLocationContext(), 339 loc::MemRegionVal(EleReg)); 340 Bldr.generateNode(CNE, *I, state); 341 } 342#endif 343} 344 345void ExprEngine::VisitCXXDeleteExpr(const CXXDeleteExpr *CDE, 346 ExplodedNode *Pred, ExplodedNodeSet &Dst) { 347 StmtNodeBuilder Bldr(Pred, Dst, *currentBuilderContext); 348 ProgramStateRef state = Pred->getState(); 349 Bldr.generateNode(CDE, Pred, state); 350} 351 352void ExprEngine::VisitCXXCatchStmt(const CXXCatchStmt *CS, 353 ExplodedNode *Pred, 354 ExplodedNodeSet &Dst) { 355 const VarDecl *VD = CS->getExceptionDecl(); 356 if (!VD) { 357 Dst.Add(Pred); 358 return; 359 } 360 361 const LocationContext *LCtx = Pred->getLocationContext(); 362 SVal V = svalBuilder.getConjuredSymbolVal(CS, LCtx, VD->getType(), 363 currentBuilderContext->getCurrentBlockCount()); 364 ProgramStateRef state = Pred->getState(); 365 state = state->bindLoc(state->getLValue(VD, LCtx), V); 366 367 StmtNodeBuilder Bldr(Pred, Dst, *currentBuilderContext); 368 Bldr.generateNode(CS, Pred, state); 369} 370 371void ExprEngine::VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred, 372 ExplodedNodeSet &Dst) { 373 StmtNodeBuilder Bldr(Pred, Dst, *currentBuilderContext); 374 375 // Get the this object region from StoreManager. 376 const LocationContext *LCtx = Pred->getLocationContext(); 377 const MemRegion *R = 378 svalBuilder.getRegionManager().getCXXThisRegion( 379 getContext().getCanonicalType(TE->getType()), 380 LCtx); 381 382 ProgramStateRef state = Pred->getState(); 383 SVal V = state->getSVal(loc::MemRegionVal(R)); 384 Bldr.generateNode(TE, Pred, state->BindExpr(TE, LCtx, V)); 385} 386