ExprEngineCXX.cpp revision dc84cd5efdd3430efb22546b4ac656aa0540b210
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/PathSensitive/ExprEngine.h" 15#include "clang/AST/DeclCXX.h" 16#include "clang/AST/StmtCXX.h" 17#include "clang/Basic/PrettyStackTrace.h" 18#include "clang/StaticAnalyzer/Core/CheckerManager.h" 19#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h" 20#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 21 22using namespace clang; 23using namespace ento; 24 25void ExprEngine::CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME, 26 ExplodedNode *Pred, 27 ExplodedNodeSet &Dst) { 28 StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx); 29 const Expr *tempExpr = ME->GetTemporaryExpr()->IgnoreParens(); 30 ProgramStateRef state = Pred->getState(); 31 const LocationContext *LCtx = Pred->getLocationContext(); 32 33 // Bind the temporary object to the value of the expression. Then bind 34 // the expression to the location of the object. 35 SVal V = state->getSVal(tempExpr, LCtx); 36 37 // If the value is already a CXXTempObjectRegion, it is fine as it is. 38 // Otherwise, create a new CXXTempObjectRegion, and copy the value into it. 39 const MemRegion *MR = V.getAsRegion(); 40 if (!MR || !isa<CXXTempObjectRegion>(MR)) { 41 const MemRegion *R = 42 svalBuilder.getRegionManager().getCXXTempObjectRegion(ME, LCtx); 43 44 SVal L = loc::MemRegionVal(R); 45 state = state->bindLoc(L, V); 46 V = L; 47 } 48 49 Bldr.generateNode(ME, Pred, state->BindExpr(ME, LCtx, V)); 50} 51 52void ExprEngine::performTrivialCopy(NodeBuilder &Bldr, ExplodedNode *Pred, 53 const CXXConstructorCall &Call) { 54 const CXXConstructExpr *CtorExpr = Call.getOriginExpr(); 55 assert(CtorExpr->getConstructor()->isCopyOrMoveConstructor()); 56 assert(CtorExpr->getConstructor()->isTrivial()); 57 58 SVal ThisVal = Call.getCXXThisVal(); 59 const LocationContext *LCtx = Pred->getLocationContext(); 60 61 ExplodedNodeSet Dst; 62 Bldr.takeNodes(Pred); 63 64 SVal V = Call.getArgSVal(0); 65 66 // Make sure the value being copied is not unknown. 67 if (Optional<Loc> L = V.getAs<Loc>()) 68 V = Pred->getState()->getSVal(*L); 69 70 evalBind(Dst, CtorExpr, Pred, ThisVal, V, true); 71 72 PostStmt PS(CtorExpr, LCtx); 73 for (ExplodedNodeSet::iterator I = Dst.begin(), E = Dst.end(); 74 I != E; ++I) { 75 ProgramStateRef State = (*I)->getState(); 76 State = bindReturnValue(Call, LCtx, State); 77 Bldr.generateNode(PS, State, *I); 78 } 79} 80 81void ExprEngine::VisitCXXConstructExpr(const CXXConstructExpr *CE, 82 ExplodedNode *Pred, 83 ExplodedNodeSet &destNodes) { 84 const LocationContext *LCtx = Pred->getLocationContext(); 85 ProgramStateRef State = Pred->getState(); 86 87 const MemRegion *Target = 0; 88 bool IsArray = false; 89 90 switch (CE->getConstructionKind()) { 91 case CXXConstructExpr::CK_Complete: { 92 // See if we're constructing an existing region by looking at the next 93 // element in the CFG. 94 const CFGBlock *B = currBldrCtx->getBlock(); 95 if (currStmtIdx + 1 < B->size()) { 96 CFGElement Next = (*B)[currStmtIdx+1]; 97 98 // Is this a constructor for a local variable? 99 if (const CFGStmt *StmtElem = dyn_cast<CFGStmt>(&Next)) { 100 if (const DeclStmt *DS = dyn_cast<DeclStmt>(StmtElem->getStmt())) { 101 if (const VarDecl *Var = dyn_cast<VarDecl>(DS->getSingleDecl())) { 102 if (Var->getInit()->IgnoreImplicit() == CE) { 103 QualType Ty = Var->getType(); 104 if (const ArrayType *AT = getContext().getAsArrayType(Ty)) { 105 // FIXME: Handle arrays, which run the same constructor for 106 // every element. This workaround will just run the first 107 // constructor (which should still invalidate the entire array). 108 SVal Base = State->getLValue(Var, LCtx); 109 Target = State->getLValue(AT->getElementType(), 110 getSValBuilder().makeZeroArrayIndex(), 111 Base).getAsRegion(); 112 IsArray = true; 113 } else { 114 Target = State->getLValue(Var, LCtx).getAsRegion(); 115 } 116 } 117 } 118 } 119 } 120 121 // Is this a constructor for a member? 122 if (const CFGInitializer *InitElem = dyn_cast<CFGInitializer>(&Next)) { 123 const CXXCtorInitializer *Init = InitElem->getInitializer(); 124 assert(Init->isAnyMemberInitializer()); 125 126 const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl()); 127 Loc ThisPtr = getSValBuilder().getCXXThis(CurCtor, 128 LCtx->getCurrentStackFrame()); 129 SVal ThisVal = State->getSVal(ThisPtr); 130 131 if (Init->isIndirectMemberInitializer()) { 132 SVal Field = State->getLValue(Init->getIndirectMember(), ThisVal); 133 Target = Field.getAsRegion(); 134 } else { 135 SVal Field = State->getLValue(Init->getMember(), ThisVal); 136 Target = Field.getAsRegion(); 137 } 138 } 139 140 // FIXME: This will eventually need to handle new-expressions as well. 141 } 142 143 // If we couldn't find an existing region to construct into, assume we're 144 // constructing a temporary. 145 if (!Target) { 146 MemRegionManager &MRMgr = getSValBuilder().getRegionManager(); 147 Target = MRMgr.getCXXTempObjectRegion(CE, LCtx); 148 } 149 150 break; 151 } 152 case CXXConstructExpr::CK_NonVirtualBase: 153 case CXXConstructExpr::CK_VirtualBase: 154 case CXXConstructExpr::CK_Delegating: { 155 const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl()); 156 Loc ThisPtr = getSValBuilder().getCXXThis(CurCtor, 157 LCtx->getCurrentStackFrame()); 158 SVal ThisVal = State->getSVal(ThisPtr); 159 160 if (CE->getConstructionKind() == CXXConstructExpr::CK_Delegating) { 161 Target = ThisVal.getAsRegion(); 162 } else { 163 // Cast to the base type. 164 QualType BaseTy = CE->getType(); 165 SVal BaseVal = getStoreManager().evalDerivedToBase(ThisVal, BaseTy); 166 Target = BaseVal.getAsRegion(); 167 } 168 break; 169 } 170 } 171 172 CallEventManager &CEMgr = getStateManager().getCallEventManager(); 173 CallEventRef<CXXConstructorCall> Call = 174 CEMgr.getCXXConstructorCall(CE, Target, State, LCtx); 175 176 ExplodedNodeSet DstPreVisit; 177 getCheckerManager().runCheckersForPreStmt(DstPreVisit, Pred, CE, *this); 178 ExplodedNodeSet DstPreCall; 179 getCheckerManager().runCheckersForPreCall(DstPreCall, DstPreVisit, 180 *Call, *this); 181 182 ExplodedNodeSet DstEvaluated; 183 StmtNodeBuilder Bldr(DstPreCall, DstEvaluated, *currBldrCtx); 184 185 if (CE->getConstructor()->isTrivial() && 186 CE->getConstructor()->isCopyOrMoveConstructor() && 187 !IsArray) { 188 // FIXME: Handle other kinds of trivial constructors as well. 189 for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end(); 190 I != E; ++I) 191 performTrivialCopy(Bldr, *I, *Call); 192 193 } else { 194 for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end(); 195 I != E; ++I) 196 defaultEvalCall(Bldr, *I, *Call); 197 } 198 199 ExplodedNodeSet DstPostCall; 200 getCheckerManager().runCheckersForPostCall(DstPostCall, DstEvaluated, 201 *Call, *this); 202 getCheckerManager().runCheckersForPostStmt(destNodes, DstPostCall, CE, *this); 203} 204 205void ExprEngine::VisitCXXDestructor(QualType ObjectType, 206 const MemRegion *Dest, 207 const Stmt *S, 208 bool IsBaseDtor, 209 ExplodedNode *Pred, 210 ExplodedNodeSet &Dst) { 211 const LocationContext *LCtx = Pred->getLocationContext(); 212 ProgramStateRef State = Pred->getState(); 213 214 // FIXME: We need to run the same destructor on every element of the array. 215 // This workaround will just run the first destructor (which will still 216 // invalidate the entire array). 217 // This is a loop because of multidimensional arrays. 218 while (const ArrayType *AT = getContext().getAsArrayType(ObjectType)) { 219 ObjectType = AT->getElementType(); 220 Dest = State->getLValue(ObjectType, getSValBuilder().makeZeroArrayIndex(), 221 loc::MemRegionVal(Dest)).getAsRegion(); 222 } 223 224 const CXXRecordDecl *RecordDecl = ObjectType->getAsCXXRecordDecl(); 225 assert(RecordDecl && "Only CXXRecordDecls should have destructors"); 226 const CXXDestructorDecl *DtorDecl = RecordDecl->getDestructor(); 227 228 CallEventManager &CEMgr = getStateManager().getCallEventManager(); 229 CallEventRef<CXXDestructorCall> Call = 230 CEMgr.getCXXDestructorCall(DtorDecl, S, Dest, IsBaseDtor, State, LCtx); 231 232 PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(), 233 Call->getSourceRange().getBegin(), 234 "Error evaluating destructor"); 235 236 ExplodedNodeSet DstPreCall; 237 getCheckerManager().runCheckersForPreCall(DstPreCall, Pred, 238 *Call, *this); 239 240 ExplodedNodeSet DstInvalidated; 241 StmtNodeBuilder Bldr(DstPreCall, DstInvalidated, *currBldrCtx); 242 for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end(); 243 I != E; ++I) 244 defaultEvalCall(Bldr, *I, *Call); 245 246 ExplodedNodeSet DstPostCall; 247 getCheckerManager().runCheckersForPostCall(Dst, DstInvalidated, 248 *Call, *this); 249} 250 251void ExprEngine::VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred, 252 ExplodedNodeSet &Dst) { 253 // FIXME: Much of this should eventually migrate to CXXAllocatorCall. 254 // Also, we need to decide how allocators actually work -- they're not 255 // really part of the CXXNewExpr because they happen BEFORE the 256 // CXXConstructExpr subexpression. See PR12014 for some discussion. 257 StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx); 258 259 unsigned blockCount = currBldrCtx->blockCount(); 260 const LocationContext *LCtx = Pred->getLocationContext(); 261 DefinedOrUnknownSVal symVal = svalBuilder.conjureSymbolVal(0, CNE, LCtx, 262 CNE->getType(), 263 blockCount); 264 ProgramStateRef State = Pred->getState(); 265 266 CallEventManager &CEMgr = getStateManager().getCallEventManager(); 267 CallEventRef<CXXAllocatorCall> Call = 268 CEMgr.getCXXAllocatorCall(CNE, State, LCtx); 269 270 // Invalidate placement args. 271 // FIXME: Once we figure out how we want allocators to work, 272 // we should be using the usual pre-/(default-)eval-/post-call checks here. 273 State = Call->invalidateRegions(blockCount); 274 275 // If we're compiling with exceptions enabled, and this allocation function 276 // is not declared as non-throwing, failures /must/ be signalled by 277 // exceptions, and thus the return value will never be NULL. 278 // C++11 [basic.stc.dynamic.allocation]p3. 279 FunctionDecl *FD = CNE->getOperatorNew(); 280 if (FD && getContext().getLangOpts().CXXExceptions) { 281 QualType Ty = FD->getType(); 282 if (const FunctionProtoType *ProtoType = Ty->getAs<FunctionProtoType>()) 283 if (!ProtoType->isNothrow(getContext())) 284 State = State->assume(symVal, true); 285 } 286 287 if (CNE->isArray()) { 288 // FIXME: allocating an array requires simulating the constructors. 289 // For now, just return a symbolicated region. 290 const MemRegion *NewReg = symVal.castAs<loc::MemRegionVal>().getRegion(); 291 QualType ObjTy = CNE->getType()->getAs<PointerType>()->getPointeeType(); 292 const ElementRegion *EleReg = 293 getStoreManager().GetElementZeroRegion(NewReg, ObjTy); 294 State = State->BindExpr(CNE, Pred->getLocationContext(), 295 loc::MemRegionVal(EleReg)); 296 Bldr.generateNode(CNE, Pred, State); 297 return; 298 } 299 300 // FIXME: Once we have proper support for CXXConstructExprs inside 301 // CXXNewExpr, we need to make sure that the constructed object is not 302 // immediately invalidated here. (The placement call should happen before 303 // the constructor call anyway.) 304 if (FD && FD->isReservedGlobalPlacementOperator()) { 305 // Non-array placement new should always return the placement location. 306 SVal PlacementLoc = State->getSVal(CNE->getPlacementArg(0), LCtx); 307 SVal Result = svalBuilder.evalCast(PlacementLoc, CNE->getType(), 308 CNE->getPlacementArg(0)->getType()); 309 State = State->BindExpr(CNE, LCtx, Result); 310 } else { 311 State = State->BindExpr(CNE, LCtx, symVal); 312 } 313 314 // If the type is not a record, we won't have a CXXConstructExpr as an 315 // initializer. Copy the value over. 316 if (const Expr *Init = CNE->getInitializer()) { 317 if (!isa<CXXConstructExpr>(Init)) { 318 QualType ObjTy = CNE->getType()->getAs<PointerType>()->getPointeeType(); 319 (void)ObjTy; 320 assert(!ObjTy->isRecordType()); 321 SVal Location = State->getSVal(CNE, LCtx); 322 if (Optional<Loc> LV = Location.getAs<Loc>()) 323 State = State->bindLoc(*LV, State->getSVal(Init, LCtx)); 324 } 325 } 326 327 Bldr.generateNode(CNE, Pred, State); 328} 329 330void ExprEngine::VisitCXXDeleteExpr(const CXXDeleteExpr *CDE, 331 ExplodedNode *Pred, ExplodedNodeSet &Dst) { 332 StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx); 333 ProgramStateRef state = Pred->getState(); 334 Bldr.generateNode(CDE, Pred, state); 335} 336 337void ExprEngine::VisitCXXCatchStmt(const CXXCatchStmt *CS, 338 ExplodedNode *Pred, 339 ExplodedNodeSet &Dst) { 340 const VarDecl *VD = CS->getExceptionDecl(); 341 if (!VD) { 342 Dst.Add(Pred); 343 return; 344 } 345 346 const LocationContext *LCtx = Pred->getLocationContext(); 347 SVal V = svalBuilder.conjureSymbolVal(CS, LCtx, VD->getType(), 348 currBldrCtx->blockCount()); 349 ProgramStateRef state = Pred->getState(); 350 state = state->bindLoc(state->getLValue(VD, LCtx), V); 351 352 StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx); 353 Bldr.generateNode(CS, Pred, state); 354} 355 356void ExprEngine::VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred, 357 ExplodedNodeSet &Dst) { 358 StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx); 359 360 // Get the this object region from StoreManager. 361 const LocationContext *LCtx = Pred->getLocationContext(); 362 const MemRegion *R = 363 svalBuilder.getRegionManager().getCXXThisRegion( 364 getContext().getCanonicalType(TE->getType()), 365 LCtx); 366 367 ProgramStateRef state = Pred->getState(); 368 SVal V = state->getSVal(loc::MemRegionVal(R)); 369 Bldr.generateNode(TE, Pred, state->BindExpr(TE, LCtx, V)); 370} 371