1 //===--- VTableBuilder.cpp - C++ vtable layout builder --------------------===// 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 contains code dealing with generation of the layout of virtual tables. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "clang/AST/VTableBuilder.h" 15 #include "clang/AST/CXXInheritance.h" 16 #include "clang/AST/RecordLayout.h" 17 #include "clang/Basic/TargetInfo.h" 18 #include "llvm/Support/Format.h" 19 #include <algorithm> 20 #include <cstdio> 21 22 using namespace clang; 23 24 #define DUMP_OVERRIDERS 0 25 26 namespace { 27 28 /// BaseOffset - Represents an offset from a derived class to a direct or 29 /// indirect base class. 30 struct BaseOffset { 31 /// DerivedClass - The derived class. 32 const CXXRecordDecl *DerivedClass; 33 34 /// VirtualBase - If the path from the derived class to the base class 35 /// involves a virtual base class, this holds its declaration. 36 const CXXRecordDecl *VirtualBase; 37 38 /// NonVirtualOffset - The offset from the derived class to the base class. 39 /// (Or the offset from the virtual base class to the base class, if the 40 /// path from the derived class to the base class involves a virtual base 41 /// class. 42 CharUnits NonVirtualOffset; 43 44 BaseOffset() : DerivedClass(0), VirtualBase(0), 45 NonVirtualOffset(CharUnits::Zero()) { } 46 BaseOffset(const CXXRecordDecl *DerivedClass, 47 const CXXRecordDecl *VirtualBase, CharUnits NonVirtualOffset) 48 : DerivedClass(DerivedClass), VirtualBase(VirtualBase), 49 NonVirtualOffset(NonVirtualOffset) { } 50 51 bool isEmpty() const { return NonVirtualOffset.isZero() && !VirtualBase; } 52 }; 53 54 /// FinalOverriders - Contains the final overrider member functions for all 55 /// member functions in the base subobjects of a class. 56 class FinalOverriders { 57 public: 58 /// OverriderInfo - Information about a final overrider. 59 struct OverriderInfo { 60 /// Method - The method decl of the overrider. 61 const CXXMethodDecl *Method; 62 63 /// Offset - the base offset of the overrider in the layout class. 64 CharUnits Offset; 65 66 OverriderInfo() : Method(0), Offset(CharUnits::Zero()) { } 67 }; 68 69 private: 70 /// MostDerivedClass - The most derived class for which the final overriders 71 /// are stored. 72 const CXXRecordDecl *MostDerivedClass; 73 74 /// MostDerivedClassOffset - If we're building final overriders for a 75 /// construction vtable, this holds the offset from the layout class to the 76 /// most derived class. 77 const CharUnits MostDerivedClassOffset; 78 79 /// LayoutClass - The class we're using for layout information. Will be 80 /// different than the most derived class if the final overriders are for a 81 /// construction vtable. 82 const CXXRecordDecl *LayoutClass; 83 84 ASTContext &Context; 85 86 /// MostDerivedClassLayout - the AST record layout of the most derived class. 87 const ASTRecordLayout &MostDerivedClassLayout; 88 89 /// MethodBaseOffsetPairTy - Uniquely identifies a member function 90 /// in a base subobject. 91 typedef std::pair<const CXXMethodDecl *, CharUnits> MethodBaseOffsetPairTy; 92 93 typedef llvm::DenseMap<MethodBaseOffsetPairTy, 94 OverriderInfo> OverridersMapTy; 95 96 /// OverridersMap - The final overriders for all virtual member functions of 97 /// all the base subobjects of the most derived class. 98 OverridersMapTy OverridersMap; 99 100 /// SubobjectsToOffsetsMapTy - A mapping from a base subobject (represented 101 /// as a record decl and a subobject number) and its offsets in the most 102 /// derived class as well as the layout class. 103 typedef llvm::DenseMap<std::pair<const CXXRecordDecl *, unsigned>, 104 CharUnits> SubobjectOffsetMapTy; 105 106 typedef llvm::DenseMap<const CXXRecordDecl *, unsigned> SubobjectCountMapTy; 107 108 /// ComputeBaseOffsets - Compute the offsets for all base subobjects of the 109 /// given base. 110 void ComputeBaseOffsets(BaseSubobject Base, bool IsVirtual, 111 CharUnits OffsetInLayoutClass, 112 SubobjectOffsetMapTy &SubobjectOffsets, 113 SubobjectOffsetMapTy &SubobjectLayoutClassOffsets, 114 SubobjectCountMapTy &SubobjectCounts); 115 116 typedef llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBasesSetTy; 117 118 /// dump - dump the final overriders for a base subobject, and all its direct 119 /// and indirect base subobjects. 120 void dump(raw_ostream &Out, BaseSubobject Base, 121 VisitedVirtualBasesSetTy& VisitedVirtualBases); 122 123 public: 124 FinalOverriders(const CXXRecordDecl *MostDerivedClass, 125 CharUnits MostDerivedClassOffset, 126 const CXXRecordDecl *LayoutClass); 127 128 /// getOverrider - Get the final overrider for the given method declaration in 129 /// the subobject with the given base offset. 130 OverriderInfo getOverrider(const CXXMethodDecl *MD, 131 CharUnits BaseOffset) const { 132 assert(OverridersMap.count(std::make_pair(MD, BaseOffset)) && 133 "Did not find overrider!"); 134 135 return OverridersMap.lookup(std::make_pair(MD, BaseOffset)); 136 } 137 138 /// dump - dump the final overriders. 139 void dump() { 140 VisitedVirtualBasesSetTy VisitedVirtualBases; 141 dump(llvm::errs(), BaseSubobject(MostDerivedClass, CharUnits::Zero()), 142 VisitedVirtualBases); 143 } 144 145 }; 146 147 #define DUMP_OVERRIDERS 0 148 149 FinalOverriders::FinalOverriders(const CXXRecordDecl *MostDerivedClass, 150 CharUnits MostDerivedClassOffset, 151 const CXXRecordDecl *LayoutClass) 152 : MostDerivedClass(MostDerivedClass), 153 MostDerivedClassOffset(MostDerivedClassOffset), LayoutClass(LayoutClass), 154 Context(MostDerivedClass->getASTContext()), 155 MostDerivedClassLayout(Context.getASTRecordLayout(MostDerivedClass)) { 156 157 // Compute base offsets. 158 SubobjectOffsetMapTy SubobjectOffsets; 159 SubobjectOffsetMapTy SubobjectLayoutClassOffsets; 160 SubobjectCountMapTy SubobjectCounts; 161 ComputeBaseOffsets(BaseSubobject(MostDerivedClass, CharUnits::Zero()), 162 /*IsVirtual=*/false, 163 MostDerivedClassOffset, 164 SubobjectOffsets, SubobjectLayoutClassOffsets, 165 SubobjectCounts); 166 167 // Get the the final overriders. 168 CXXFinalOverriderMap FinalOverriders; 169 MostDerivedClass->getFinalOverriders(FinalOverriders); 170 171 for (CXXFinalOverriderMap::const_iterator I = FinalOverriders.begin(), 172 E = FinalOverriders.end(); I != E; ++I) { 173 const CXXMethodDecl *MD = I->first; 174 const OverridingMethods& Methods = I->second; 175 176 for (OverridingMethods::const_iterator I = Methods.begin(), 177 E = Methods.end(); I != E; ++I) { 178 unsigned SubobjectNumber = I->first; 179 assert(SubobjectOffsets.count(std::make_pair(MD->getParent(), 180 SubobjectNumber)) && 181 "Did not find subobject offset!"); 182 183 CharUnits BaseOffset = SubobjectOffsets[std::make_pair(MD->getParent(), 184 SubobjectNumber)]; 185 186 assert(I->second.size() == 1 && "Final overrider is not unique!"); 187 const UniqueVirtualMethod &Method = I->second.front(); 188 189 const CXXRecordDecl *OverriderRD = Method.Method->getParent(); 190 assert(SubobjectLayoutClassOffsets.count( 191 std::make_pair(OverriderRD, Method.Subobject)) 192 && "Did not find subobject offset!"); 193 CharUnits OverriderOffset = 194 SubobjectLayoutClassOffsets[std::make_pair(OverriderRD, 195 Method.Subobject)]; 196 197 OverriderInfo& Overrider = OverridersMap[std::make_pair(MD, BaseOffset)]; 198 assert(!Overrider.Method && "Overrider should not exist yet!"); 199 200 Overrider.Offset = OverriderOffset; 201 Overrider.Method = Method.Method; 202 } 203 } 204 205 #if DUMP_OVERRIDERS 206 // And dump them (for now). 207 dump(); 208 #endif 209 } 210 211 static BaseOffset ComputeBaseOffset(ASTContext &Context, 212 const CXXRecordDecl *DerivedRD, 213 const CXXBasePath &Path) { 214 CharUnits NonVirtualOffset = CharUnits::Zero(); 215 216 unsigned NonVirtualStart = 0; 217 const CXXRecordDecl *VirtualBase = 0; 218 219 // First, look for the virtual base class. 220 for (unsigned I = 0, E = Path.size(); I != E; ++I) { 221 const CXXBasePathElement &Element = Path[I]; 222 223 if (Element.Base->isVirtual()) { 224 // FIXME: Can we break when we find the first virtual base? 225 // (If we can't, can't we just iterate over the path in reverse order?) 226 NonVirtualStart = I + 1; 227 QualType VBaseType = Element.Base->getType(); 228 VirtualBase = 229 cast<CXXRecordDecl>(VBaseType->getAs<RecordType>()->getDecl()); 230 } 231 } 232 233 // Now compute the non-virtual offset. 234 for (unsigned I = NonVirtualStart, E = Path.size(); I != E; ++I) { 235 const CXXBasePathElement &Element = Path[I]; 236 237 // Check the base class offset. 238 const ASTRecordLayout &Layout = Context.getASTRecordLayout(Element.Class); 239 240 const RecordType *BaseType = Element.Base->getType()->getAs<RecordType>(); 241 const CXXRecordDecl *Base = cast<CXXRecordDecl>(BaseType->getDecl()); 242 243 NonVirtualOffset += Layout.getBaseClassOffset(Base); 244 } 245 246 // FIXME: This should probably use CharUnits or something. Maybe we should 247 // even change the base offsets in ASTRecordLayout to be specified in 248 // CharUnits. 249 return BaseOffset(DerivedRD, VirtualBase, NonVirtualOffset); 250 251 } 252 253 static BaseOffset ComputeBaseOffset(ASTContext &Context, 254 const CXXRecordDecl *BaseRD, 255 const CXXRecordDecl *DerivedRD) { 256 CXXBasePaths Paths(/*FindAmbiguities=*/false, 257 /*RecordPaths=*/true, /*DetectVirtual=*/false); 258 259 if (!const_cast<CXXRecordDecl *>(DerivedRD)-> 260 isDerivedFrom(const_cast<CXXRecordDecl *>(BaseRD), Paths)) { 261 llvm_unreachable("Class must be derived from the passed in base class!"); 262 } 263 264 return ComputeBaseOffset(Context, DerivedRD, Paths.front()); 265 } 266 267 static BaseOffset 268 ComputeReturnAdjustmentBaseOffset(ASTContext &Context, 269 const CXXMethodDecl *DerivedMD, 270 const CXXMethodDecl *BaseMD) { 271 const FunctionType *BaseFT = BaseMD->getType()->getAs<FunctionType>(); 272 const FunctionType *DerivedFT = DerivedMD->getType()->getAs<FunctionType>(); 273 274 // Canonicalize the return types. 275 CanQualType CanDerivedReturnType = 276 Context.getCanonicalType(DerivedFT->getResultType()); 277 CanQualType CanBaseReturnType = 278 Context.getCanonicalType(BaseFT->getResultType()); 279 280 assert(CanDerivedReturnType->getTypeClass() == 281 CanBaseReturnType->getTypeClass() && 282 "Types must have same type class!"); 283 284 if (CanDerivedReturnType == CanBaseReturnType) { 285 // No adjustment needed. 286 return BaseOffset(); 287 } 288 289 if (isa<ReferenceType>(CanDerivedReturnType)) { 290 CanDerivedReturnType = 291 CanDerivedReturnType->getAs<ReferenceType>()->getPointeeType(); 292 CanBaseReturnType = 293 CanBaseReturnType->getAs<ReferenceType>()->getPointeeType(); 294 } else if (isa<PointerType>(CanDerivedReturnType)) { 295 CanDerivedReturnType = 296 CanDerivedReturnType->getAs<PointerType>()->getPointeeType(); 297 CanBaseReturnType = 298 CanBaseReturnType->getAs<PointerType>()->getPointeeType(); 299 } else { 300 llvm_unreachable("Unexpected return type!"); 301 } 302 303 // We need to compare unqualified types here; consider 304 // const T *Base::foo(); 305 // T *Derived::foo(); 306 if (CanDerivedReturnType.getUnqualifiedType() == 307 CanBaseReturnType.getUnqualifiedType()) { 308 // No adjustment needed. 309 return BaseOffset(); 310 } 311 312 const CXXRecordDecl *DerivedRD = 313 cast<CXXRecordDecl>(cast<RecordType>(CanDerivedReturnType)->getDecl()); 314 315 const CXXRecordDecl *BaseRD = 316 cast<CXXRecordDecl>(cast<RecordType>(CanBaseReturnType)->getDecl()); 317 318 return ComputeBaseOffset(Context, BaseRD, DerivedRD); 319 } 320 321 void 322 FinalOverriders::ComputeBaseOffsets(BaseSubobject Base, bool IsVirtual, 323 CharUnits OffsetInLayoutClass, 324 SubobjectOffsetMapTy &SubobjectOffsets, 325 SubobjectOffsetMapTy &SubobjectLayoutClassOffsets, 326 SubobjectCountMapTy &SubobjectCounts) { 327 const CXXRecordDecl *RD = Base.getBase(); 328 329 unsigned SubobjectNumber = 0; 330 if (!IsVirtual) 331 SubobjectNumber = ++SubobjectCounts[RD]; 332 333 // Set up the subobject to offset mapping. 334 assert(!SubobjectOffsets.count(std::make_pair(RD, SubobjectNumber)) 335 && "Subobject offset already exists!"); 336 assert(!SubobjectLayoutClassOffsets.count(std::make_pair(RD, SubobjectNumber)) 337 && "Subobject offset already exists!"); 338 339 SubobjectOffsets[std::make_pair(RD, SubobjectNumber)] = Base.getBaseOffset(); 340 SubobjectLayoutClassOffsets[std::make_pair(RD, SubobjectNumber)] = 341 OffsetInLayoutClass; 342 343 // Traverse our bases. 344 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), 345 E = RD->bases_end(); I != E; ++I) { 346 const CXXRecordDecl *BaseDecl = 347 cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl()); 348 349 CharUnits BaseOffset; 350 CharUnits BaseOffsetInLayoutClass; 351 if (I->isVirtual()) { 352 // Check if we've visited this virtual base before. 353 if (SubobjectOffsets.count(std::make_pair(BaseDecl, 0))) 354 continue; 355 356 const ASTRecordLayout &LayoutClassLayout = 357 Context.getASTRecordLayout(LayoutClass); 358 359 BaseOffset = MostDerivedClassLayout.getVBaseClassOffset(BaseDecl); 360 BaseOffsetInLayoutClass = 361 LayoutClassLayout.getVBaseClassOffset(BaseDecl); 362 } else { 363 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); 364 CharUnits Offset = Layout.getBaseClassOffset(BaseDecl); 365 366 BaseOffset = Base.getBaseOffset() + Offset; 367 BaseOffsetInLayoutClass = OffsetInLayoutClass + Offset; 368 } 369 370 ComputeBaseOffsets(BaseSubobject(BaseDecl, BaseOffset), 371 I->isVirtual(), BaseOffsetInLayoutClass, 372 SubobjectOffsets, SubobjectLayoutClassOffsets, 373 SubobjectCounts); 374 } 375 } 376 377 void FinalOverriders::dump(raw_ostream &Out, BaseSubobject Base, 378 VisitedVirtualBasesSetTy &VisitedVirtualBases) { 379 const CXXRecordDecl *RD = Base.getBase(); 380 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); 381 382 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), 383 E = RD->bases_end(); I != E; ++I) { 384 const CXXRecordDecl *BaseDecl = 385 cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl()); 386 387 // Ignore bases that don't have any virtual member functions. 388 if (!BaseDecl->isPolymorphic()) 389 continue; 390 391 CharUnits BaseOffset; 392 if (I->isVirtual()) { 393 if (!VisitedVirtualBases.insert(BaseDecl)) { 394 // We've visited this base before. 395 continue; 396 } 397 398 BaseOffset = MostDerivedClassLayout.getVBaseClassOffset(BaseDecl); 399 } else { 400 BaseOffset = Layout.getBaseClassOffset(BaseDecl) + Base.getBaseOffset(); 401 } 402 403 dump(Out, BaseSubobject(BaseDecl, BaseOffset), VisitedVirtualBases); 404 } 405 406 Out << "Final overriders for (" << RD->getQualifiedNameAsString() << ", "; 407 Out << Base.getBaseOffset().getQuantity() << ")\n"; 408 409 // Now dump the overriders for this base subobject. 410 for (CXXRecordDecl::method_iterator I = RD->method_begin(), 411 E = RD->method_end(); I != E; ++I) { 412 const CXXMethodDecl *MD = *I; 413 414 if (!MD->isVirtual()) 415 continue; 416 417 OverriderInfo Overrider = getOverrider(MD, Base.getBaseOffset()); 418 419 Out << " " << MD->getQualifiedNameAsString() << " - ("; 420 Out << Overrider.Method->getQualifiedNameAsString(); 421 Out << ", " << ", " << Overrider.Offset.getQuantity() << ')'; 422 423 BaseOffset Offset; 424 if (!Overrider.Method->isPure()) 425 Offset = ComputeReturnAdjustmentBaseOffset(Context, Overrider.Method, MD); 426 427 if (!Offset.isEmpty()) { 428 Out << " [ret-adj: "; 429 if (Offset.VirtualBase) 430 Out << Offset.VirtualBase->getQualifiedNameAsString() << " vbase, "; 431 432 Out << Offset.NonVirtualOffset.getQuantity() << " nv]"; 433 } 434 435 Out << "\n"; 436 } 437 } 438 439 /// VCallOffsetMap - Keeps track of vcall offsets when building a vtable. 440 struct VCallOffsetMap { 441 442 typedef std::pair<const CXXMethodDecl *, CharUnits> MethodAndOffsetPairTy; 443 444 /// Offsets - Keeps track of methods and their offsets. 445 // FIXME: This should be a real map and not a vector. 446 SmallVector<MethodAndOffsetPairTy, 16> Offsets; 447 448 /// MethodsCanShareVCallOffset - Returns whether two virtual member functions 449 /// can share the same vcall offset. 450 static bool MethodsCanShareVCallOffset(const CXXMethodDecl *LHS, 451 const CXXMethodDecl *RHS); 452 453 public: 454 /// AddVCallOffset - Adds a vcall offset to the map. Returns true if the 455 /// add was successful, or false if there was already a member function with 456 /// the same signature in the map. 457 bool AddVCallOffset(const CXXMethodDecl *MD, CharUnits OffsetOffset); 458 459 /// getVCallOffsetOffset - Returns the vcall offset offset (relative to the 460 /// vtable address point) for the given virtual member function. 461 CharUnits getVCallOffsetOffset(const CXXMethodDecl *MD); 462 463 // empty - Return whether the offset map is empty or not. 464 bool empty() const { return Offsets.empty(); } 465 }; 466 467 static bool HasSameVirtualSignature(const CXXMethodDecl *LHS, 468 const CXXMethodDecl *RHS) { 469 const FunctionProtoType *LT = 470 cast<FunctionProtoType>(LHS->getType().getCanonicalType()); 471 const FunctionProtoType *RT = 472 cast<FunctionProtoType>(RHS->getType().getCanonicalType()); 473 474 // Fast-path matches in the canonical types. 475 if (LT == RT) return true; 476 477 // Force the signatures to match. We can't rely on the overrides 478 // list here because there isn't necessarily an inheritance 479 // relationship between the two methods. 480 if (LT->getTypeQuals() != RT->getTypeQuals() || 481 LT->getNumArgs() != RT->getNumArgs()) 482 return false; 483 for (unsigned I = 0, E = LT->getNumArgs(); I != E; ++I) 484 if (LT->getArgType(I) != RT->getArgType(I)) 485 return false; 486 return true; 487 } 488 489 bool VCallOffsetMap::MethodsCanShareVCallOffset(const CXXMethodDecl *LHS, 490 const CXXMethodDecl *RHS) { 491 assert(LHS->isVirtual() && "LHS must be virtual!"); 492 assert(RHS->isVirtual() && "LHS must be virtual!"); 493 494 // A destructor can share a vcall offset with another destructor. 495 if (isa<CXXDestructorDecl>(LHS)) 496 return isa<CXXDestructorDecl>(RHS); 497 498 // FIXME: We need to check more things here. 499 500 // The methods must have the same name. 501 DeclarationName LHSName = LHS->getDeclName(); 502 DeclarationName RHSName = RHS->getDeclName(); 503 if (LHSName != RHSName) 504 return false; 505 506 // And the same signatures. 507 return HasSameVirtualSignature(LHS, RHS); 508 } 509 510 bool VCallOffsetMap::AddVCallOffset(const CXXMethodDecl *MD, 511 CharUnits OffsetOffset) { 512 // Check if we can reuse an offset. 513 for (unsigned I = 0, E = Offsets.size(); I != E; ++I) { 514 if (MethodsCanShareVCallOffset(Offsets[I].first, MD)) 515 return false; 516 } 517 518 // Add the offset. 519 Offsets.push_back(MethodAndOffsetPairTy(MD, OffsetOffset)); 520 return true; 521 } 522 523 CharUnits VCallOffsetMap::getVCallOffsetOffset(const CXXMethodDecl *MD) { 524 // Look for an offset. 525 for (unsigned I = 0, E = Offsets.size(); I != E; ++I) { 526 if (MethodsCanShareVCallOffset(Offsets[I].first, MD)) 527 return Offsets[I].second; 528 } 529 530 llvm_unreachable("Should always find a vcall offset offset!"); 531 } 532 533 /// VCallAndVBaseOffsetBuilder - Class for building vcall and vbase offsets. 534 class VCallAndVBaseOffsetBuilder { 535 public: 536 typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> 537 VBaseOffsetOffsetsMapTy; 538 539 private: 540 /// MostDerivedClass - The most derived class for which we're building vcall 541 /// and vbase offsets. 542 const CXXRecordDecl *MostDerivedClass; 543 544 /// LayoutClass - The class we're using for layout information. Will be 545 /// different than the most derived class if we're building a construction 546 /// vtable. 547 const CXXRecordDecl *LayoutClass; 548 549 /// Context - The ASTContext which we will use for layout information. 550 ASTContext &Context; 551 552 /// Components - vcall and vbase offset components 553 typedef SmallVector<VTableComponent, 64> VTableComponentVectorTy; 554 VTableComponentVectorTy Components; 555 556 /// VisitedVirtualBases - Visited virtual bases. 557 llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBases; 558 559 /// VCallOffsets - Keeps track of vcall offsets. 560 VCallOffsetMap VCallOffsets; 561 562 563 /// VBaseOffsetOffsets - Contains the offsets of the virtual base offsets, 564 /// relative to the address point. 565 VBaseOffsetOffsetsMapTy VBaseOffsetOffsets; 566 567 /// FinalOverriders - The final overriders of the most derived class. 568 /// (Can be null when we're not building a vtable of the most derived class). 569 const FinalOverriders *Overriders; 570 571 /// AddVCallAndVBaseOffsets - Add vcall offsets and vbase offsets for the 572 /// given base subobject. 573 void AddVCallAndVBaseOffsets(BaseSubobject Base, bool BaseIsVirtual, 574 CharUnits RealBaseOffset); 575 576 /// AddVCallOffsets - Add vcall offsets for the given base subobject. 577 void AddVCallOffsets(BaseSubobject Base, CharUnits VBaseOffset); 578 579 /// AddVBaseOffsets - Add vbase offsets for the given class. 580 void AddVBaseOffsets(const CXXRecordDecl *Base, 581 CharUnits OffsetInLayoutClass); 582 583 /// getCurrentOffsetOffset - Get the current vcall or vbase offset offset in 584 /// chars, relative to the vtable address point. 585 CharUnits getCurrentOffsetOffset() const; 586 587 public: 588 VCallAndVBaseOffsetBuilder(const CXXRecordDecl *MostDerivedClass, 589 const CXXRecordDecl *LayoutClass, 590 const FinalOverriders *Overriders, 591 BaseSubobject Base, bool BaseIsVirtual, 592 CharUnits OffsetInLayoutClass) 593 : MostDerivedClass(MostDerivedClass), LayoutClass(LayoutClass), 594 Context(MostDerivedClass->getASTContext()), Overriders(Overriders) { 595 596 // Add vcall and vbase offsets. 597 AddVCallAndVBaseOffsets(Base, BaseIsVirtual, OffsetInLayoutClass); 598 } 599 600 /// Methods for iterating over the components. 601 typedef VTableComponentVectorTy::const_reverse_iterator const_iterator; 602 const_iterator components_begin() const { return Components.rbegin(); } 603 const_iterator components_end() const { return Components.rend(); } 604 605 const VCallOffsetMap &getVCallOffsets() const { return VCallOffsets; } 606 const VBaseOffsetOffsetsMapTy &getVBaseOffsetOffsets() const { 607 return VBaseOffsetOffsets; 608 } 609 }; 610 611 void 612 VCallAndVBaseOffsetBuilder::AddVCallAndVBaseOffsets(BaseSubobject Base, 613 bool BaseIsVirtual, 614 CharUnits RealBaseOffset) { 615 const ASTRecordLayout &Layout = Context.getASTRecordLayout(Base.getBase()); 616 617 // Itanium C++ ABI 2.5.2: 618 // ..in classes sharing a virtual table with a primary base class, the vcall 619 // and vbase offsets added by the derived class all come before the vcall 620 // and vbase offsets required by the base class, so that the latter may be 621 // laid out as required by the base class without regard to additions from 622 // the derived class(es). 623 624 // (Since we're emitting the vcall and vbase offsets in reverse order, we'll 625 // emit them for the primary base first). 626 if (const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase()) { 627 bool PrimaryBaseIsVirtual = Layout.isPrimaryBaseVirtual(); 628 629 CharUnits PrimaryBaseOffset; 630 631 // Get the base offset of the primary base. 632 if (PrimaryBaseIsVirtual) { 633 assert(Layout.getVBaseClassOffsetInBits(PrimaryBase) == 0 && 634 "Primary vbase should have a zero offset!"); 635 636 const ASTRecordLayout &MostDerivedClassLayout = 637 Context.getASTRecordLayout(MostDerivedClass); 638 639 PrimaryBaseOffset = 640 MostDerivedClassLayout.getVBaseClassOffset(PrimaryBase); 641 } else { 642 assert(Layout.getBaseClassOffsetInBits(PrimaryBase) == 0 && 643 "Primary base should have a zero offset!"); 644 645 PrimaryBaseOffset = Base.getBaseOffset(); 646 } 647 648 AddVCallAndVBaseOffsets( 649 BaseSubobject(PrimaryBase,PrimaryBaseOffset), 650 PrimaryBaseIsVirtual, RealBaseOffset); 651 } 652 653 AddVBaseOffsets(Base.getBase(), RealBaseOffset); 654 655 // We only want to add vcall offsets for virtual bases. 656 if (BaseIsVirtual) 657 AddVCallOffsets(Base, RealBaseOffset); 658 } 659 660 CharUnits VCallAndVBaseOffsetBuilder::getCurrentOffsetOffset() const { 661 // OffsetIndex is the index of this vcall or vbase offset, relative to the 662 // vtable address point. (We subtract 3 to account for the information just 663 // above the address point, the RTTI info, the offset to top, and the 664 // vcall offset itself). 665 int64_t OffsetIndex = -(int64_t)(3 + Components.size()); 666 667 CharUnits PointerWidth = 668 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0)); 669 CharUnits OffsetOffset = PointerWidth * OffsetIndex; 670 return OffsetOffset; 671 } 672 673 void VCallAndVBaseOffsetBuilder::AddVCallOffsets(BaseSubobject Base, 674 CharUnits VBaseOffset) { 675 const CXXRecordDecl *RD = Base.getBase(); 676 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); 677 678 const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase(); 679 680 // Handle the primary base first. 681 // We only want to add vcall offsets if the base is non-virtual; a virtual 682 // primary base will have its vcall and vbase offsets emitted already. 683 if (PrimaryBase && !Layout.isPrimaryBaseVirtual()) { 684 // Get the base offset of the primary base. 685 assert(Layout.getBaseClassOffsetInBits(PrimaryBase) == 0 && 686 "Primary base should have a zero offset!"); 687 688 AddVCallOffsets(BaseSubobject(PrimaryBase, Base.getBaseOffset()), 689 VBaseOffset); 690 } 691 692 // Add the vcall offsets. 693 for (CXXRecordDecl::method_iterator I = RD->method_begin(), 694 E = RD->method_end(); I != E; ++I) { 695 const CXXMethodDecl *MD = *I; 696 697 if (!MD->isVirtual()) 698 continue; 699 700 CharUnits OffsetOffset = getCurrentOffsetOffset(); 701 702 // Don't add a vcall offset if we already have one for this member function 703 // signature. 704 if (!VCallOffsets.AddVCallOffset(MD, OffsetOffset)) 705 continue; 706 707 CharUnits Offset = CharUnits::Zero(); 708 709 if (Overriders) { 710 // Get the final overrider. 711 FinalOverriders::OverriderInfo Overrider = 712 Overriders->getOverrider(MD, Base.getBaseOffset()); 713 714 /// The vcall offset is the offset from the virtual base to the object 715 /// where the function was overridden. 716 Offset = Overrider.Offset - VBaseOffset; 717 } 718 719 Components.push_back( 720 VTableComponent::MakeVCallOffset(Offset)); 721 } 722 723 // And iterate over all non-virtual bases (ignoring the primary base). 724 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), 725 E = RD->bases_end(); I != E; ++I) { 726 727 if (I->isVirtual()) 728 continue; 729 730 const CXXRecordDecl *BaseDecl = 731 cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl()); 732 if (BaseDecl == PrimaryBase) 733 continue; 734 735 // Get the base offset of this base. 736 CharUnits BaseOffset = Base.getBaseOffset() + 737 Layout.getBaseClassOffset(BaseDecl); 738 739 AddVCallOffsets(BaseSubobject(BaseDecl, BaseOffset), 740 VBaseOffset); 741 } 742 } 743 744 void 745 VCallAndVBaseOffsetBuilder::AddVBaseOffsets(const CXXRecordDecl *RD, 746 CharUnits OffsetInLayoutClass) { 747 const ASTRecordLayout &LayoutClassLayout = 748 Context.getASTRecordLayout(LayoutClass); 749 750 // Add vbase offsets. 751 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), 752 E = RD->bases_end(); I != E; ++I) { 753 const CXXRecordDecl *BaseDecl = 754 cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl()); 755 756 // Check if this is a virtual base that we haven't visited before. 757 if (I->isVirtual() && VisitedVirtualBases.insert(BaseDecl)) { 758 CharUnits Offset = 759 LayoutClassLayout.getVBaseClassOffset(BaseDecl) - OffsetInLayoutClass; 760 761 // Add the vbase offset offset. 762 assert(!VBaseOffsetOffsets.count(BaseDecl) && 763 "vbase offset offset already exists!"); 764 765 CharUnits VBaseOffsetOffset = getCurrentOffsetOffset(); 766 VBaseOffsetOffsets.insert( 767 std::make_pair(BaseDecl, VBaseOffsetOffset)); 768 769 Components.push_back( 770 VTableComponent::MakeVBaseOffset(Offset)); 771 } 772 773 // Check the base class looking for more vbase offsets. 774 AddVBaseOffsets(BaseDecl, OffsetInLayoutClass); 775 } 776 } 777 778 /// VTableBuilder - Class for building vtable layout information. 779 class VTableBuilder { 780 public: 781 /// PrimaryBasesSetVectorTy - A set vector of direct and indirect 782 /// primary bases. 783 typedef llvm::SmallSetVector<const CXXRecordDecl *, 8> 784 PrimaryBasesSetVectorTy; 785 786 typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> 787 VBaseOffsetOffsetsMapTy; 788 789 typedef llvm::DenseMap<BaseSubobject, uint64_t> 790 AddressPointsMapTy; 791 792 private: 793 /// VTables - Global vtable information. 794 VTableContext &VTables; 795 796 /// MostDerivedClass - The most derived class for which we're building this 797 /// vtable. 798 const CXXRecordDecl *MostDerivedClass; 799 800 /// MostDerivedClassOffset - If we're building a construction vtable, this 801 /// holds the offset from the layout class to the most derived class. 802 const CharUnits MostDerivedClassOffset; 803 804 /// MostDerivedClassIsVirtual - Whether the most derived class is a virtual 805 /// base. (This only makes sense when building a construction vtable). 806 bool MostDerivedClassIsVirtual; 807 808 /// LayoutClass - The class we're using for layout information. Will be 809 /// different than the most derived class if we're building a construction 810 /// vtable. 811 const CXXRecordDecl *LayoutClass; 812 813 /// Context - The ASTContext which we will use for layout information. 814 ASTContext &Context; 815 816 /// FinalOverriders - The final overriders of the most derived class. 817 const FinalOverriders Overriders; 818 819 /// VCallOffsetsForVBases - Keeps track of vcall offsets for the virtual 820 /// bases in this vtable. 821 llvm::DenseMap<const CXXRecordDecl *, VCallOffsetMap> VCallOffsetsForVBases; 822 823 /// VBaseOffsetOffsets - Contains the offsets of the virtual base offsets for 824 /// the most derived class. 825 VBaseOffsetOffsetsMapTy VBaseOffsetOffsets; 826 827 /// Components - The components of the vtable being built. 828 SmallVector<VTableComponent, 64> Components; 829 830 /// AddressPoints - Address points for the vtable being built. 831 AddressPointsMapTy AddressPoints; 832 833 /// MethodInfo - Contains information about a method in a vtable. 834 /// (Used for computing 'this' pointer adjustment thunks. 835 struct MethodInfo { 836 /// BaseOffset - The base offset of this method. 837 const CharUnits BaseOffset; 838 839 /// BaseOffsetInLayoutClass - The base offset in the layout class of this 840 /// method. 841 const CharUnits BaseOffsetInLayoutClass; 842 843 /// VTableIndex - The index in the vtable that this method has. 844 /// (For destructors, this is the index of the complete destructor). 845 const uint64_t VTableIndex; 846 847 MethodInfo(CharUnits BaseOffset, CharUnits BaseOffsetInLayoutClass, 848 uint64_t VTableIndex) 849 : BaseOffset(BaseOffset), 850 BaseOffsetInLayoutClass(BaseOffsetInLayoutClass), 851 VTableIndex(VTableIndex) { } 852 853 MethodInfo() 854 : BaseOffset(CharUnits::Zero()), 855 BaseOffsetInLayoutClass(CharUnits::Zero()), 856 VTableIndex(0) { } 857 }; 858 859 typedef llvm::DenseMap<const CXXMethodDecl *, MethodInfo> MethodInfoMapTy; 860 861 /// MethodInfoMap - The information for all methods in the vtable we're 862 /// currently building. 863 MethodInfoMapTy MethodInfoMap; 864 865 typedef llvm::DenseMap<uint64_t, ThunkInfo> VTableThunksMapTy; 866 867 /// VTableThunks - The thunks by vtable index in the vtable currently being 868 /// built. 869 VTableThunksMapTy VTableThunks; 870 871 typedef SmallVector<ThunkInfo, 1> ThunkInfoVectorTy; 872 typedef llvm::DenseMap<const CXXMethodDecl *, ThunkInfoVectorTy> ThunksMapTy; 873 874 /// Thunks - A map that contains all the thunks needed for all methods in the 875 /// most derived class for which the vtable is currently being built. 876 ThunksMapTy Thunks; 877 878 /// AddThunk - Add a thunk for the given method. 879 void AddThunk(const CXXMethodDecl *MD, const ThunkInfo &Thunk); 880 881 /// ComputeThisAdjustments - Compute the 'this' pointer adjustments for the 882 /// part of the vtable we're currently building. 883 void ComputeThisAdjustments(); 884 885 typedef llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBasesSetTy; 886 887 /// PrimaryVirtualBases - All known virtual bases who are a primary base of 888 /// some other base. 889 VisitedVirtualBasesSetTy PrimaryVirtualBases; 890 891 /// ComputeReturnAdjustment - Compute the return adjustment given a return 892 /// adjustment base offset. 893 ReturnAdjustment ComputeReturnAdjustment(BaseOffset Offset); 894 895 /// ComputeThisAdjustmentBaseOffset - Compute the base offset for adjusting 896 /// the 'this' pointer from the base subobject to the derived subobject. 897 BaseOffset ComputeThisAdjustmentBaseOffset(BaseSubobject Base, 898 BaseSubobject Derived) const; 899 900 /// ComputeThisAdjustment - Compute the 'this' pointer adjustment for the 901 /// given virtual member function, its offset in the layout class and its 902 /// final overrider. 903 ThisAdjustment 904 ComputeThisAdjustment(const CXXMethodDecl *MD, 905 CharUnits BaseOffsetInLayoutClass, 906 FinalOverriders::OverriderInfo Overrider); 907 908 /// AddMethod - Add a single virtual member function to the vtable 909 /// components vector. 910 void AddMethod(const CXXMethodDecl *MD, ReturnAdjustment ReturnAdjustment); 911 912 /// IsOverriderUsed - Returns whether the overrider will ever be used in this 913 /// part of the vtable. 914 /// 915 /// Itanium C++ ABI 2.5.2: 916 /// 917 /// struct A { virtual void f(); }; 918 /// struct B : virtual public A { int i; }; 919 /// struct C : virtual public A { int j; }; 920 /// struct D : public B, public C {}; 921 /// 922 /// When B and C are declared, A is a primary base in each case, so although 923 /// vcall offsets are allocated in the A-in-B and A-in-C vtables, no this 924 /// adjustment is required and no thunk is generated. However, inside D 925 /// objects, A is no longer a primary base of C, so if we allowed calls to 926 /// C::f() to use the copy of A's vtable in the C subobject, we would need 927 /// to adjust this from C* to B::A*, which would require a third-party 928 /// thunk. Since we require that a call to C::f() first convert to A*, 929 /// C-in-D's copy of A's vtable is never referenced, so this is not 930 /// necessary. 931 bool IsOverriderUsed(const CXXMethodDecl *Overrider, 932 CharUnits BaseOffsetInLayoutClass, 933 const CXXRecordDecl *FirstBaseInPrimaryBaseChain, 934 CharUnits FirstBaseOffsetInLayoutClass) const; 935 936 937 /// AddMethods - Add the methods of this base subobject and all its 938 /// primary bases to the vtable components vector. 939 void AddMethods(BaseSubobject Base, CharUnits BaseOffsetInLayoutClass, 940 const CXXRecordDecl *FirstBaseInPrimaryBaseChain, 941 CharUnits FirstBaseOffsetInLayoutClass, 942 PrimaryBasesSetVectorTy &PrimaryBases); 943 944 // LayoutVTable - Layout the vtable for the given base class, including its 945 // secondary vtables and any vtables for virtual bases. 946 void LayoutVTable(); 947 948 /// LayoutPrimaryAndSecondaryVTables - Layout the primary vtable for the 949 /// given base subobject, as well as all its secondary vtables. 950 /// 951 /// \param BaseIsMorallyVirtual whether the base subobject is a virtual base 952 /// or a direct or indirect base of a virtual base. 953 /// 954 /// \param BaseIsVirtualInLayoutClass - Whether the base subobject is virtual 955 /// in the layout class. 956 void LayoutPrimaryAndSecondaryVTables(BaseSubobject Base, 957 bool BaseIsMorallyVirtual, 958 bool BaseIsVirtualInLayoutClass, 959 CharUnits OffsetInLayoutClass); 960 961 /// LayoutSecondaryVTables - Layout the secondary vtables for the given base 962 /// subobject. 963 /// 964 /// \param BaseIsMorallyVirtual whether the base subobject is a virtual base 965 /// or a direct or indirect base of a virtual base. 966 void LayoutSecondaryVTables(BaseSubobject Base, bool BaseIsMorallyVirtual, 967 CharUnits OffsetInLayoutClass); 968 969 /// DeterminePrimaryVirtualBases - Determine the primary virtual bases in this 970 /// class hierarchy. 971 void DeterminePrimaryVirtualBases(const CXXRecordDecl *RD, 972 CharUnits OffsetInLayoutClass, 973 VisitedVirtualBasesSetTy &VBases); 974 975 /// LayoutVTablesForVirtualBases - Layout vtables for all virtual bases of the 976 /// given base (excluding any primary bases). 977 void LayoutVTablesForVirtualBases(const CXXRecordDecl *RD, 978 VisitedVirtualBasesSetTy &VBases); 979 980 /// isBuildingConstructionVTable - Return whether this vtable builder is 981 /// building a construction vtable. 982 bool isBuildingConstructorVTable() const { 983 return MostDerivedClass != LayoutClass; 984 } 985 986 public: 987 VTableBuilder(VTableContext &VTables, const CXXRecordDecl *MostDerivedClass, 988 CharUnits MostDerivedClassOffset, 989 bool MostDerivedClassIsVirtual, const 990 CXXRecordDecl *LayoutClass) 991 : VTables(VTables), MostDerivedClass(MostDerivedClass), 992 MostDerivedClassOffset(MostDerivedClassOffset), 993 MostDerivedClassIsVirtual(MostDerivedClassIsVirtual), 994 LayoutClass(LayoutClass), Context(MostDerivedClass->getASTContext()), 995 Overriders(MostDerivedClass, MostDerivedClassOffset, LayoutClass) { 996 997 LayoutVTable(); 998 999 if (Context.getLangOpts().DumpVTableLayouts) 1000 dumpLayout(llvm::errs()); 1001 } 1002 1003 uint64_t getNumThunks() const { 1004 return Thunks.size(); 1005 } 1006 1007 ThunksMapTy::const_iterator thunks_begin() const { 1008 return Thunks.begin(); 1009 } 1010 1011 ThunksMapTy::const_iterator thunks_end() const { 1012 return Thunks.end(); 1013 } 1014 1015 const VBaseOffsetOffsetsMapTy &getVBaseOffsetOffsets() const { 1016 return VBaseOffsetOffsets; 1017 } 1018 1019 const AddressPointsMapTy &getAddressPoints() const { 1020 return AddressPoints; 1021 } 1022 1023 /// getNumVTableComponents - Return the number of components in the vtable 1024 /// currently built. 1025 uint64_t getNumVTableComponents() const { 1026 return Components.size(); 1027 } 1028 1029 const VTableComponent *vtable_component_begin() const { 1030 return Components.begin(); 1031 } 1032 1033 const VTableComponent *vtable_component_end() const { 1034 return Components.end(); 1035 } 1036 1037 AddressPointsMapTy::const_iterator address_points_begin() const { 1038 return AddressPoints.begin(); 1039 } 1040 1041 AddressPointsMapTy::const_iterator address_points_end() const { 1042 return AddressPoints.end(); 1043 } 1044 1045 VTableThunksMapTy::const_iterator vtable_thunks_begin() const { 1046 return VTableThunks.begin(); 1047 } 1048 1049 VTableThunksMapTy::const_iterator vtable_thunks_end() const { 1050 return VTableThunks.end(); 1051 } 1052 1053 /// dumpLayout - Dump the vtable layout. 1054 void dumpLayout(raw_ostream&); 1055 }; 1056 1057 void VTableBuilder::AddThunk(const CXXMethodDecl *MD, const ThunkInfo &Thunk) { 1058 assert(!isBuildingConstructorVTable() && 1059 "Can't add thunks for construction vtable"); 1060 1061 SmallVector<ThunkInfo, 1> &ThunksVector = Thunks[MD]; 1062 1063 // Check if we have this thunk already. 1064 if (std::find(ThunksVector.begin(), ThunksVector.end(), Thunk) != 1065 ThunksVector.end()) 1066 return; 1067 1068 ThunksVector.push_back(Thunk); 1069 } 1070 1071 typedef llvm::SmallPtrSet<const CXXMethodDecl *, 8> OverriddenMethodsSetTy; 1072 1073 /// ComputeAllOverriddenMethods - Given a method decl, will return a set of all 1074 /// the overridden methods that the function decl overrides. 1075 static void 1076 ComputeAllOverriddenMethods(const CXXMethodDecl *MD, 1077 OverriddenMethodsSetTy& OverriddenMethods) { 1078 assert(MD->isVirtual() && "Method is not virtual!"); 1079 1080 for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(), 1081 E = MD->end_overridden_methods(); I != E; ++I) { 1082 const CXXMethodDecl *OverriddenMD = *I; 1083 1084 OverriddenMethods.insert(OverriddenMD); 1085 1086 ComputeAllOverriddenMethods(OverriddenMD, OverriddenMethods); 1087 } 1088 } 1089 1090 void VTableBuilder::ComputeThisAdjustments() { 1091 // Now go through the method info map and see if any of the methods need 1092 // 'this' pointer adjustments. 1093 for (MethodInfoMapTy::const_iterator I = MethodInfoMap.begin(), 1094 E = MethodInfoMap.end(); I != E; ++I) { 1095 const CXXMethodDecl *MD = I->first; 1096 const MethodInfo &MethodInfo = I->second; 1097 1098 // Ignore adjustments for unused function pointers. 1099 uint64_t VTableIndex = MethodInfo.VTableIndex; 1100 if (Components[VTableIndex].getKind() == 1101 VTableComponent::CK_UnusedFunctionPointer) 1102 continue; 1103 1104 // Get the final overrider for this method. 1105 FinalOverriders::OverriderInfo Overrider = 1106 Overriders.getOverrider(MD, MethodInfo.BaseOffset); 1107 1108 // Check if we need an adjustment at all. 1109 if (MethodInfo.BaseOffsetInLayoutClass == Overrider.Offset) { 1110 // When a return thunk is needed by a derived class that overrides a 1111 // virtual base, gcc uses a virtual 'this' adjustment as well. 1112 // While the thunk itself might be needed by vtables in subclasses or 1113 // in construction vtables, there doesn't seem to be a reason for using 1114 // the thunk in this vtable. Still, we do so to match gcc. 1115 if (VTableThunks.lookup(VTableIndex).Return.isEmpty()) 1116 continue; 1117 } 1118 1119 ThisAdjustment ThisAdjustment = 1120 ComputeThisAdjustment(MD, MethodInfo.BaseOffsetInLayoutClass, Overrider); 1121 1122 if (ThisAdjustment.isEmpty()) 1123 continue; 1124 1125 // Add it. 1126 VTableThunks[VTableIndex].This = ThisAdjustment; 1127 1128 if (isa<CXXDestructorDecl>(MD)) { 1129 // Add an adjustment for the deleting destructor as well. 1130 VTableThunks[VTableIndex + 1].This = ThisAdjustment; 1131 } 1132 } 1133 1134 /// Clear the method info map. 1135 MethodInfoMap.clear(); 1136 1137 if (isBuildingConstructorVTable()) { 1138 // We don't need to store thunk information for construction vtables. 1139 return; 1140 } 1141 1142 for (VTableThunksMapTy::const_iterator I = VTableThunks.begin(), 1143 E = VTableThunks.end(); I != E; ++I) { 1144 const VTableComponent &Component = Components[I->first]; 1145 const ThunkInfo &Thunk = I->second; 1146 const CXXMethodDecl *MD; 1147 1148 switch (Component.getKind()) { 1149 default: 1150 llvm_unreachable("Unexpected vtable component kind!"); 1151 case VTableComponent::CK_FunctionPointer: 1152 MD = Component.getFunctionDecl(); 1153 break; 1154 case VTableComponent::CK_CompleteDtorPointer: 1155 MD = Component.getDestructorDecl(); 1156 break; 1157 case VTableComponent::CK_DeletingDtorPointer: 1158 // We've already added the thunk when we saw the complete dtor pointer. 1159 continue; 1160 } 1161 1162 if (MD->getParent() == MostDerivedClass) 1163 AddThunk(MD, Thunk); 1164 } 1165 } 1166 1167 ReturnAdjustment VTableBuilder::ComputeReturnAdjustment(BaseOffset Offset) { 1168 ReturnAdjustment Adjustment; 1169 1170 if (!Offset.isEmpty()) { 1171 if (Offset.VirtualBase) { 1172 // Get the virtual base offset offset. 1173 if (Offset.DerivedClass == MostDerivedClass) { 1174 // We can get the offset offset directly from our map. 1175 Adjustment.VBaseOffsetOffset = 1176 VBaseOffsetOffsets.lookup(Offset.VirtualBase).getQuantity(); 1177 } else { 1178 Adjustment.VBaseOffsetOffset = 1179 VTables.getVirtualBaseOffsetOffset(Offset.DerivedClass, 1180 Offset.VirtualBase).getQuantity(); 1181 } 1182 } 1183 1184 Adjustment.NonVirtual = Offset.NonVirtualOffset.getQuantity(); 1185 } 1186 1187 return Adjustment; 1188 } 1189 1190 BaseOffset 1191 VTableBuilder::ComputeThisAdjustmentBaseOffset(BaseSubobject Base, 1192 BaseSubobject Derived) const { 1193 const CXXRecordDecl *BaseRD = Base.getBase(); 1194 const CXXRecordDecl *DerivedRD = Derived.getBase(); 1195 1196 CXXBasePaths Paths(/*FindAmbiguities=*/true, 1197 /*RecordPaths=*/true, /*DetectVirtual=*/true); 1198 1199 if (!const_cast<CXXRecordDecl *>(DerivedRD)-> 1200 isDerivedFrom(const_cast<CXXRecordDecl *>(BaseRD), Paths)) { 1201 llvm_unreachable("Class must be derived from the passed in base class!"); 1202 } 1203 1204 // We have to go through all the paths, and see which one leads us to the 1205 // right base subobject. 1206 for (CXXBasePaths::const_paths_iterator I = Paths.begin(), E = Paths.end(); 1207 I != E; ++I) { 1208 BaseOffset Offset = ComputeBaseOffset(Context, DerivedRD, *I); 1209 1210 CharUnits OffsetToBaseSubobject = Offset.NonVirtualOffset; 1211 1212 if (Offset.VirtualBase) { 1213 // If we have a virtual base class, the non-virtual offset is relative 1214 // to the virtual base class offset. 1215 const ASTRecordLayout &LayoutClassLayout = 1216 Context.getASTRecordLayout(LayoutClass); 1217 1218 /// Get the virtual base offset, relative to the most derived class 1219 /// layout. 1220 OffsetToBaseSubobject += 1221 LayoutClassLayout.getVBaseClassOffset(Offset.VirtualBase); 1222 } else { 1223 // Otherwise, the non-virtual offset is relative to the derived class 1224 // offset. 1225 OffsetToBaseSubobject += Derived.getBaseOffset(); 1226 } 1227 1228 // Check if this path gives us the right base subobject. 1229 if (OffsetToBaseSubobject == Base.getBaseOffset()) { 1230 // Since we're going from the base class _to_ the derived class, we'll 1231 // invert the non-virtual offset here. 1232 Offset.NonVirtualOffset = -Offset.NonVirtualOffset; 1233 return Offset; 1234 } 1235 } 1236 1237 return BaseOffset(); 1238 } 1239 1240 ThisAdjustment 1241 VTableBuilder::ComputeThisAdjustment(const CXXMethodDecl *MD, 1242 CharUnits BaseOffsetInLayoutClass, 1243 FinalOverriders::OverriderInfo Overrider) { 1244 // Ignore adjustments for pure virtual member functions. 1245 if (Overrider.Method->isPure()) 1246 return ThisAdjustment(); 1247 1248 BaseSubobject OverriddenBaseSubobject(MD->getParent(), 1249 BaseOffsetInLayoutClass); 1250 1251 BaseSubobject OverriderBaseSubobject(Overrider.Method->getParent(), 1252 Overrider.Offset); 1253 1254 // Compute the adjustment offset. 1255 BaseOffset Offset = ComputeThisAdjustmentBaseOffset(OverriddenBaseSubobject, 1256 OverriderBaseSubobject); 1257 if (Offset.isEmpty()) 1258 return ThisAdjustment(); 1259 1260 ThisAdjustment Adjustment; 1261 1262 if (Offset.VirtualBase) { 1263 // Get the vcall offset map for this virtual base. 1264 VCallOffsetMap &VCallOffsets = VCallOffsetsForVBases[Offset.VirtualBase]; 1265 1266 if (VCallOffsets.empty()) { 1267 // We don't have vcall offsets for this virtual base, go ahead and 1268 // build them. 1269 VCallAndVBaseOffsetBuilder Builder(MostDerivedClass, MostDerivedClass, 1270 /*FinalOverriders=*/0, 1271 BaseSubobject(Offset.VirtualBase, 1272 CharUnits::Zero()), 1273 /*BaseIsVirtual=*/true, 1274 /*OffsetInLayoutClass=*/ 1275 CharUnits::Zero()); 1276 1277 VCallOffsets = Builder.getVCallOffsets(); 1278 } 1279 1280 Adjustment.VCallOffsetOffset = 1281 VCallOffsets.getVCallOffsetOffset(MD).getQuantity(); 1282 } 1283 1284 // Set the non-virtual part of the adjustment. 1285 Adjustment.NonVirtual = Offset.NonVirtualOffset.getQuantity(); 1286 1287 return Adjustment; 1288 } 1289 1290 void 1291 VTableBuilder::AddMethod(const CXXMethodDecl *MD, 1292 ReturnAdjustment ReturnAdjustment) { 1293 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) { 1294 assert(ReturnAdjustment.isEmpty() && 1295 "Destructor can't have return adjustment!"); 1296 1297 // Add both the complete destructor and the deleting destructor. 1298 Components.push_back(VTableComponent::MakeCompleteDtor(DD)); 1299 Components.push_back(VTableComponent::MakeDeletingDtor(DD)); 1300 } else { 1301 // Add the return adjustment if necessary. 1302 if (!ReturnAdjustment.isEmpty()) 1303 VTableThunks[Components.size()].Return = ReturnAdjustment; 1304 1305 // Add the function. 1306 Components.push_back(VTableComponent::MakeFunction(MD)); 1307 } 1308 } 1309 1310 /// OverridesIndirectMethodInBase - Return whether the given member function 1311 /// overrides any methods in the set of given bases. 1312 /// Unlike OverridesMethodInBase, this checks "overriders of overriders". 1313 /// For example, if we have: 1314 /// 1315 /// struct A { virtual void f(); } 1316 /// struct B : A { virtual void f(); } 1317 /// struct C : B { virtual void f(); } 1318 /// 1319 /// OverridesIndirectMethodInBase will return true if given C::f as the method 1320 /// and { A } as the set of bases. 1321 static bool 1322 OverridesIndirectMethodInBases(const CXXMethodDecl *MD, 1323 VTableBuilder::PrimaryBasesSetVectorTy &Bases) { 1324 if (Bases.count(MD->getParent())) 1325 return true; 1326 1327 for (CXXMethodDecl::method_iterator I = MD->begin_overridden_methods(), 1328 E = MD->end_overridden_methods(); I != E; ++I) { 1329 const CXXMethodDecl *OverriddenMD = *I; 1330 1331 // Check "indirect overriders". 1332 if (OverridesIndirectMethodInBases(OverriddenMD, Bases)) 1333 return true; 1334 } 1335 1336 return false; 1337 } 1338 1339 bool 1340 VTableBuilder::IsOverriderUsed(const CXXMethodDecl *Overrider, 1341 CharUnits BaseOffsetInLayoutClass, 1342 const CXXRecordDecl *FirstBaseInPrimaryBaseChain, 1343 CharUnits FirstBaseOffsetInLayoutClass) const { 1344 // If the base and the first base in the primary base chain have the same 1345 // offsets, then this overrider will be used. 1346 if (BaseOffsetInLayoutClass == FirstBaseOffsetInLayoutClass) 1347 return true; 1348 1349 // We know now that Base (or a direct or indirect base of it) is a primary 1350 // base in part of the class hierarchy, but not a primary base in the most 1351 // derived class. 1352 1353 // If the overrider is the first base in the primary base chain, we know 1354 // that the overrider will be used. 1355 if (Overrider->getParent() == FirstBaseInPrimaryBaseChain) 1356 return true; 1357 1358 VTableBuilder::PrimaryBasesSetVectorTy PrimaryBases; 1359 1360 const CXXRecordDecl *RD = FirstBaseInPrimaryBaseChain; 1361 PrimaryBases.insert(RD); 1362 1363 // Now traverse the base chain, starting with the first base, until we find 1364 // the base that is no longer a primary base. 1365 while (true) { 1366 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); 1367 const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase(); 1368 1369 if (!PrimaryBase) 1370 break; 1371 1372 if (Layout.isPrimaryBaseVirtual()) { 1373 assert(Layout.getVBaseClassOffsetInBits(PrimaryBase) == 0 && 1374 "Primary base should always be at offset 0!"); 1375 1376 const ASTRecordLayout &LayoutClassLayout = 1377 Context.getASTRecordLayout(LayoutClass); 1378 1379 // Now check if this is the primary base that is not a primary base in the 1380 // most derived class. 1381 if (LayoutClassLayout.getVBaseClassOffset(PrimaryBase) != 1382 FirstBaseOffsetInLayoutClass) { 1383 // We found it, stop walking the chain. 1384 break; 1385 } 1386 } else { 1387 assert(Layout.getBaseClassOffsetInBits(PrimaryBase) == 0 && 1388 "Primary base should always be at offset 0!"); 1389 } 1390 1391 if (!PrimaryBases.insert(PrimaryBase)) 1392 llvm_unreachable("Found a duplicate primary base!"); 1393 1394 RD = PrimaryBase; 1395 } 1396 1397 // If the final overrider is an override of one of the primary bases, 1398 // then we know that it will be used. 1399 return OverridesIndirectMethodInBases(Overrider, PrimaryBases); 1400 } 1401 1402 /// FindNearestOverriddenMethod - Given a method, returns the overridden method 1403 /// from the nearest base. Returns null if no method was found. 1404 static const CXXMethodDecl * 1405 FindNearestOverriddenMethod(const CXXMethodDecl *MD, 1406 VTableBuilder::PrimaryBasesSetVectorTy &Bases) { 1407 OverriddenMethodsSetTy OverriddenMethods; 1408 ComputeAllOverriddenMethods(MD, OverriddenMethods); 1409 1410 for (int I = Bases.size(), E = 0; I != E; --I) { 1411 const CXXRecordDecl *PrimaryBase = Bases[I - 1]; 1412 1413 // Now check the overriden methods. 1414 for (OverriddenMethodsSetTy::const_iterator I = OverriddenMethods.begin(), 1415 E = OverriddenMethods.end(); I != E; ++I) { 1416 const CXXMethodDecl *OverriddenMD = *I; 1417 1418 // We found our overridden method. 1419 if (OverriddenMD->getParent() == PrimaryBase) 1420 return OverriddenMD; 1421 } 1422 } 1423 1424 return 0; 1425 } 1426 1427 void 1428 VTableBuilder::AddMethods(BaseSubobject Base, CharUnits BaseOffsetInLayoutClass, 1429 const CXXRecordDecl *FirstBaseInPrimaryBaseChain, 1430 CharUnits FirstBaseOffsetInLayoutClass, 1431 PrimaryBasesSetVectorTy &PrimaryBases) { 1432 const CXXRecordDecl *RD = Base.getBase(); 1433 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); 1434 1435 if (const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase()) { 1436 CharUnits PrimaryBaseOffset; 1437 CharUnits PrimaryBaseOffsetInLayoutClass; 1438 if (Layout.isPrimaryBaseVirtual()) { 1439 assert(Layout.getVBaseClassOffsetInBits(PrimaryBase) == 0 && 1440 "Primary vbase should have a zero offset!"); 1441 1442 const ASTRecordLayout &MostDerivedClassLayout = 1443 Context.getASTRecordLayout(MostDerivedClass); 1444 1445 PrimaryBaseOffset = 1446 MostDerivedClassLayout.getVBaseClassOffset(PrimaryBase); 1447 1448 const ASTRecordLayout &LayoutClassLayout = 1449 Context.getASTRecordLayout(LayoutClass); 1450 1451 PrimaryBaseOffsetInLayoutClass = 1452 LayoutClassLayout.getVBaseClassOffset(PrimaryBase); 1453 } else { 1454 assert(Layout.getBaseClassOffsetInBits(PrimaryBase) == 0 && 1455 "Primary base should have a zero offset!"); 1456 1457 PrimaryBaseOffset = Base.getBaseOffset(); 1458 PrimaryBaseOffsetInLayoutClass = BaseOffsetInLayoutClass; 1459 } 1460 1461 AddMethods(BaseSubobject(PrimaryBase, PrimaryBaseOffset), 1462 PrimaryBaseOffsetInLayoutClass, FirstBaseInPrimaryBaseChain, 1463 FirstBaseOffsetInLayoutClass, PrimaryBases); 1464 1465 if (!PrimaryBases.insert(PrimaryBase)) 1466 llvm_unreachable("Found a duplicate primary base!"); 1467 } 1468 1469 // Now go through all virtual member functions and add them. 1470 for (CXXRecordDecl::method_iterator I = RD->method_begin(), 1471 E = RD->method_end(); I != E; ++I) { 1472 const CXXMethodDecl *MD = *I; 1473 1474 if (!MD->isVirtual()) 1475 continue; 1476 1477 // Get the final overrider. 1478 FinalOverriders::OverriderInfo Overrider = 1479 Overriders.getOverrider(MD, Base.getBaseOffset()); 1480 1481 // Check if this virtual member function overrides a method in a primary 1482 // base. If this is the case, and the return type doesn't require adjustment 1483 // then we can just use the member function from the primary base. 1484 if (const CXXMethodDecl *OverriddenMD = 1485 FindNearestOverriddenMethod(MD, PrimaryBases)) { 1486 if (ComputeReturnAdjustmentBaseOffset(Context, MD, 1487 OverriddenMD).isEmpty()) { 1488 // Replace the method info of the overridden method with our own 1489 // method. 1490 assert(MethodInfoMap.count(OverriddenMD) && 1491 "Did not find the overridden method!"); 1492 MethodInfo &OverriddenMethodInfo = MethodInfoMap[OverriddenMD]; 1493 1494 MethodInfo MethodInfo(Base.getBaseOffset(), BaseOffsetInLayoutClass, 1495 OverriddenMethodInfo.VTableIndex); 1496 1497 assert(!MethodInfoMap.count(MD) && 1498 "Should not have method info for this method yet!"); 1499 1500 MethodInfoMap.insert(std::make_pair(MD, MethodInfo)); 1501 MethodInfoMap.erase(OverriddenMD); 1502 1503 // If the overridden method exists in a virtual base class or a direct 1504 // or indirect base class of a virtual base class, we need to emit a 1505 // thunk if we ever have a class hierarchy where the base class is not 1506 // a primary base in the complete object. 1507 if (!isBuildingConstructorVTable() && OverriddenMD != MD) { 1508 // Compute the this adjustment. 1509 ThisAdjustment ThisAdjustment = 1510 ComputeThisAdjustment(OverriddenMD, BaseOffsetInLayoutClass, 1511 Overrider); 1512 1513 if (ThisAdjustment.VCallOffsetOffset && 1514 Overrider.Method->getParent() == MostDerivedClass) { 1515 1516 // There's no return adjustment from OverriddenMD and MD, 1517 // but that doesn't mean there isn't one between MD and 1518 // the final overrider. 1519 BaseOffset ReturnAdjustmentOffset = 1520 ComputeReturnAdjustmentBaseOffset(Context, Overrider.Method, MD); 1521 ReturnAdjustment ReturnAdjustment = 1522 ComputeReturnAdjustment(ReturnAdjustmentOffset); 1523 1524 // This is a virtual thunk for the most derived class, add it. 1525 AddThunk(Overrider.Method, 1526 ThunkInfo(ThisAdjustment, ReturnAdjustment)); 1527 } 1528 } 1529 1530 continue; 1531 } 1532 } 1533 1534 // Insert the method info for this method. 1535 MethodInfo MethodInfo(Base.getBaseOffset(), BaseOffsetInLayoutClass, 1536 Components.size()); 1537 1538 assert(!MethodInfoMap.count(MD) && 1539 "Should not have method info for this method yet!"); 1540 MethodInfoMap.insert(std::make_pair(MD, MethodInfo)); 1541 1542 // Check if this overrider is going to be used. 1543 const CXXMethodDecl *OverriderMD = Overrider.Method; 1544 if (!IsOverriderUsed(OverriderMD, BaseOffsetInLayoutClass, 1545 FirstBaseInPrimaryBaseChain, 1546 FirstBaseOffsetInLayoutClass)) { 1547 Components.push_back(VTableComponent::MakeUnusedFunction(OverriderMD)); 1548 continue; 1549 } 1550 1551 // Check if this overrider needs a return adjustment. 1552 // We don't want to do this for pure virtual member functions. 1553 BaseOffset ReturnAdjustmentOffset; 1554 if (!OverriderMD->isPure()) { 1555 ReturnAdjustmentOffset = 1556 ComputeReturnAdjustmentBaseOffset(Context, OverriderMD, MD); 1557 } 1558 1559 ReturnAdjustment ReturnAdjustment = 1560 ComputeReturnAdjustment(ReturnAdjustmentOffset); 1561 1562 AddMethod(Overrider.Method, ReturnAdjustment); 1563 } 1564 } 1565 1566 void VTableBuilder::LayoutVTable() { 1567 LayoutPrimaryAndSecondaryVTables(BaseSubobject(MostDerivedClass, 1568 CharUnits::Zero()), 1569 /*BaseIsMorallyVirtual=*/false, 1570 MostDerivedClassIsVirtual, 1571 MostDerivedClassOffset); 1572 1573 VisitedVirtualBasesSetTy VBases; 1574 1575 // Determine the primary virtual bases. 1576 DeterminePrimaryVirtualBases(MostDerivedClass, MostDerivedClassOffset, 1577 VBases); 1578 VBases.clear(); 1579 1580 LayoutVTablesForVirtualBases(MostDerivedClass, VBases); 1581 1582 // -fapple-kext adds an extra entry at end of vtbl. 1583 bool IsAppleKext = Context.getLangOpts().AppleKext; 1584 if (IsAppleKext) 1585 Components.push_back(VTableComponent::MakeVCallOffset(CharUnits::Zero())); 1586 } 1587 1588 void 1589 VTableBuilder::LayoutPrimaryAndSecondaryVTables(BaseSubobject Base, 1590 bool BaseIsMorallyVirtual, 1591 bool BaseIsVirtualInLayoutClass, 1592 CharUnits OffsetInLayoutClass) { 1593 assert(Base.getBase()->isDynamicClass() && "class does not have a vtable!"); 1594 1595 // Add vcall and vbase offsets for this vtable. 1596 VCallAndVBaseOffsetBuilder Builder(MostDerivedClass, LayoutClass, &Overriders, 1597 Base, BaseIsVirtualInLayoutClass, 1598 OffsetInLayoutClass); 1599 Components.append(Builder.components_begin(), Builder.components_end()); 1600 1601 // Check if we need to add these vcall offsets. 1602 if (BaseIsVirtualInLayoutClass && !Builder.getVCallOffsets().empty()) { 1603 VCallOffsetMap &VCallOffsets = VCallOffsetsForVBases[Base.getBase()]; 1604 1605 if (VCallOffsets.empty()) 1606 VCallOffsets = Builder.getVCallOffsets(); 1607 } 1608 1609 // If we're laying out the most derived class we want to keep track of the 1610 // virtual base class offset offsets. 1611 if (Base.getBase() == MostDerivedClass) 1612 VBaseOffsetOffsets = Builder.getVBaseOffsetOffsets(); 1613 1614 // Add the offset to top. 1615 CharUnits OffsetToTop = MostDerivedClassOffset - OffsetInLayoutClass; 1616 Components.push_back( 1617 VTableComponent::MakeOffsetToTop(OffsetToTop)); 1618 1619 // Next, add the RTTI. 1620 Components.push_back(VTableComponent::MakeRTTI(MostDerivedClass)); 1621 1622 uint64_t AddressPoint = Components.size(); 1623 1624 // Now go through all virtual member functions and add them. 1625 PrimaryBasesSetVectorTy PrimaryBases; 1626 AddMethods(Base, OffsetInLayoutClass, 1627 Base.getBase(), OffsetInLayoutClass, 1628 PrimaryBases); 1629 1630 // Compute 'this' pointer adjustments. 1631 ComputeThisAdjustments(); 1632 1633 // Add all address points. 1634 const CXXRecordDecl *RD = Base.getBase(); 1635 while (true) { 1636 AddressPoints.insert(std::make_pair( 1637 BaseSubobject(RD, OffsetInLayoutClass), 1638 AddressPoint)); 1639 1640 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); 1641 const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase(); 1642 1643 if (!PrimaryBase) 1644 break; 1645 1646 if (Layout.isPrimaryBaseVirtual()) { 1647 // Check if this virtual primary base is a primary base in the layout 1648 // class. If it's not, we don't want to add it. 1649 const ASTRecordLayout &LayoutClassLayout = 1650 Context.getASTRecordLayout(LayoutClass); 1651 1652 if (LayoutClassLayout.getVBaseClassOffset(PrimaryBase) != 1653 OffsetInLayoutClass) { 1654 // We don't want to add this class (or any of its primary bases). 1655 break; 1656 } 1657 } 1658 1659 RD = PrimaryBase; 1660 } 1661 1662 // Layout secondary vtables. 1663 LayoutSecondaryVTables(Base, BaseIsMorallyVirtual, OffsetInLayoutClass); 1664 } 1665 1666 void VTableBuilder::LayoutSecondaryVTables(BaseSubobject Base, 1667 bool BaseIsMorallyVirtual, 1668 CharUnits OffsetInLayoutClass) { 1669 // Itanium C++ ABI 2.5.2: 1670 // Following the primary virtual table of a derived class are secondary 1671 // virtual tables for each of its proper base classes, except any primary 1672 // base(s) with which it shares its primary virtual table. 1673 1674 const CXXRecordDecl *RD = Base.getBase(); 1675 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); 1676 const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase(); 1677 1678 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), 1679 E = RD->bases_end(); I != E; ++I) { 1680 // Ignore virtual bases, we'll emit them later. 1681 if (I->isVirtual()) 1682 continue; 1683 1684 const CXXRecordDecl *BaseDecl = 1685 cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl()); 1686 1687 // Ignore bases that don't have a vtable. 1688 if (!BaseDecl->isDynamicClass()) 1689 continue; 1690 1691 if (isBuildingConstructorVTable()) { 1692 // Itanium C++ ABI 2.6.4: 1693 // Some of the base class subobjects may not need construction virtual 1694 // tables, which will therefore not be present in the construction 1695 // virtual table group, even though the subobject virtual tables are 1696 // present in the main virtual table group for the complete object. 1697 if (!BaseIsMorallyVirtual && !BaseDecl->getNumVBases()) 1698 continue; 1699 } 1700 1701 // Get the base offset of this base. 1702 CharUnits RelativeBaseOffset = Layout.getBaseClassOffset(BaseDecl); 1703 CharUnits BaseOffset = Base.getBaseOffset() + RelativeBaseOffset; 1704 1705 CharUnits BaseOffsetInLayoutClass = 1706 OffsetInLayoutClass + RelativeBaseOffset; 1707 1708 // Don't emit a secondary vtable for a primary base. We might however want 1709 // to emit secondary vtables for other bases of this base. 1710 if (BaseDecl == PrimaryBase) { 1711 LayoutSecondaryVTables(BaseSubobject(BaseDecl, BaseOffset), 1712 BaseIsMorallyVirtual, BaseOffsetInLayoutClass); 1713 continue; 1714 } 1715 1716 // Layout the primary vtable (and any secondary vtables) for this base. 1717 LayoutPrimaryAndSecondaryVTables( 1718 BaseSubobject(BaseDecl, BaseOffset), 1719 BaseIsMorallyVirtual, 1720 /*BaseIsVirtualInLayoutClass=*/false, 1721 BaseOffsetInLayoutClass); 1722 } 1723 } 1724 1725 void 1726 VTableBuilder::DeterminePrimaryVirtualBases(const CXXRecordDecl *RD, 1727 CharUnits OffsetInLayoutClass, 1728 VisitedVirtualBasesSetTy &VBases) { 1729 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); 1730 1731 // Check if this base has a primary base. 1732 if (const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase()) { 1733 1734 // Check if it's virtual. 1735 if (Layout.isPrimaryBaseVirtual()) { 1736 bool IsPrimaryVirtualBase = true; 1737 1738 if (isBuildingConstructorVTable()) { 1739 // Check if the base is actually a primary base in the class we use for 1740 // layout. 1741 const ASTRecordLayout &LayoutClassLayout = 1742 Context.getASTRecordLayout(LayoutClass); 1743 1744 CharUnits PrimaryBaseOffsetInLayoutClass = 1745 LayoutClassLayout.getVBaseClassOffset(PrimaryBase); 1746 1747 // We know that the base is not a primary base in the layout class if 1748 // the base offsets are different. 1749 if (PrimaryBaseOffsetInLayoutClass != OffsetInLayoutClass) 1750 IsPrimaryVirtualBase = false; 1751 } 1752 1753 if (IsPrimaryVirtualBase) 1754 PrimaryVirtualBases.insert(PrimaryBase); 1755 } 1756 } 1757 1758 // Traverse bases, looking for more primary virtual bases. 1759 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), 1760 E = RD->bases_end(); I != E; ++I) { 1761 const CXXRecordDecl *BaseDecl = 1762 cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl()); 1763 1764 CharUnits BaseOffsetInLayoutClass; 1765 1766 if (I->isVirtual()) { 1767 if (!VBases.insert(BaseDecl)) 1768 continue; 1769 1770 const ASTRecordLayout &LayoutClassLayout = 1771 Context.getASTRecordLayout(LayoutClass); 1772 1773 BaseOffsetInLayoutClass = 1774 LayoutClassLayout.getVBaseClassOffset(BaseDecl); 1775 } else { 1776 BaseOffsetInLayoutClass = 1777 OffsetInLayoutClass + Layout.getBaseClassOffset(BaseDecl); 1778 } 1779 1780 DeterminePrimaryVirtualBases(BaseDecl, BaseOffsetInLayoutClass, VBases); 1781 } 1782 } 1783 1784 void 1785 VTableBuilder::LayoutVTablesForVirtualBases(const CXXRecordDecl *RD, 1786 VisitedVirtualBasesSetTy &VBases) { 1787 // Itanium C++ ABI 2.5.2: 1788 // Then come the virtual base virtual tables, also in inheritance graph 1789 // order, and again excluding primary bases (which share virtual tables with 1790 // the classes for which they are primary). 1791 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), 1792 E = RD->bases_end(); I != E; ++I) { 1793 const CXXRecordDecl *BaseDecl = 1794 cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl()); 1795 1796 // Check if this base needs a vtable. (If it's virtual, not a primary base 1797 // of some other class, and we haven't visited it before). 1798 if (I->isVirtual() && BaseDecl->isDynamicClass() && 1799 !PrimaryVirtualBases.count(BaseDecl) && VBases.insert(BaseDecl)) { 1800 const ASTRecordLayout &MostDerivedClassLayout = 1801 Context.getASTRecordLayout(MostDerivedClass); 1802 CharUnits BaseOffset = 1803 MostDerivedClassLayout.getVBaseClassOffset(BaseDecl); 1804 1805 const ASTRecordLayout &LayoutClassLayout = 1806 Context.getASTRecordLayout(LayoutClass); 1807 CharUnits BaseOffsetInLayoutClass = 1808 LayoutClassLayout.getVBaseClassOffset(BaseDecl); 1809 1810 LayoutPrimaryAndSecondaryVTables( 1811 BaseSubobject(BaseDecl, BaseOffset), 1812 /*BaseIsMorallyVirtual=*/true, 1813 /*BaseIsVirtualInLayoutClass=*/true, 1814 BaseOffsetInLayoutClass); 1815 } 1816 1817 // We only need to check the base for virtual base vtables if it actually 1818 // has virtual bases. 1819 if (BaseDecl->getNumVBases()) 1820 LayoutVTablesForVirtualBases(BaseDecl, VBases); 1821 } 1822 } 1823 1824 /// dumpLayout - Dump the vtable layout. 1825 void VTableBuilder::dumpLayout(raw_ostream& Out) { 1826 1827 if (isBuildingConstructorVTable()) { 1828 Out << "Construction vtable for ('"; 1829 Out << MostDerivedClass->getQualifiedNameAsString() << "', "; 1830 Out << MostDerivedClassOffset.getQuantity() << ") in '"; 1831 Out << LayoutClass->getQualifiedNameAsString(); 1832 } else { 1833 Out << "Vtable for '"; 1834 Out << MostDerivedClass->getQualifiedNameAsString(); 1835 } 1836 Out << "' (" << Components.size() << " entries).\n"; 1837 1838 // Iterate through the address points and insert them into a new map where 1839 // they are keyed by the index and not the base object. 1840 // Since an address point can be shared by multiple subobjects, we use an 1841 // STL multimap. 1842 std::multimap<uint64_t, BaseSubobject> AddressPointsByIndex; 1843 for (AddressPointsMapTy::const_iterator I = AddressPoints.begin(), 1844 E = AddressPoints.end(); I != E; ++I) { 1845 const BaseSubobject& Base = I->first; 1846 uint64_t Index = I->second; 1847 1848 AddressPointsByIndex.insert(std::make_pair(Index, Base)); 1849 } 1850 1851 for (unsigned I = 0, E = Components.size(); I != E; ++I) { 1852 uint64_t Index = I; 1853 1854 Out << llvm::format("%4d | ", I); 1855 1856 const VTableComponent &Component = Components[I]; 1857 1858 // Dump the component. 1859 switch (Component.getKind()) { 1860 1861 case VTableComponent::CK_VCallOffset: 1862 Out << "vcall_offset (" 1863 << Component.getVCallOffset().getQuantity() 1864 << ")"; 1865 break; 1866 1867 case VTableComponent::CK_VBaseOffset: 1868 Out << "vbase_offset (" 1869 << Component.getVBaseOffset().getQuantity() 1870 << ")"; 1871 break; 1872 1873 case VTableComponent::CK_OffsetToTop: 1874 Out << "offset_to_top (" 1875 << Component.getOffsetToTop().getQuantity() 1876 << ")"; 1877 break; 1878 1879 case VTableComponent::CK_RTTI: 1880 Out << Component.getRTTIDecl()->getQualifiedNameAsString() << " RTTI"; 1881 break; 1882 1883 case VTableComponent::CK_FunctionPointer: { 1884 const CXXMethodDecl *MD = Component.getFunctionDecl(); 1885 1886 std::string Str = 1887 PredefinedExpr::ComputeName(PredefinedExpr::PrettyFunctionNoVirtual, 1888 MD); 1889 Out << Str; 1890 if (MD->isPure()) 1891 Out << " [pure]"; 1892 1893 ThunkInfo Thunk = VTableThunks.lookup(I); 1894 if (!Thunk.isEmpty()) { 1895 // If this function pointer has a return adjustment, dump it. 1896 if (!Thunk.Return.isEmpty()) { 1897 Out << "\n [return adjustment: "; 1898 Out << Thunk.Return.NonVirtual << " non-virtual"; 1899 1900 if (Thunk.Return.VBaseOffsetOffset) { 1901 Out << ", " << Thunk.Return.VBaseOffsetOffset; 1902 Out << " vbase offset offset"; 1903 } 1904 1905 Out << ']'; 1906 } 1907 1908 // If this function pointer has a 'this' pointer adjustment, dump it. 1909 if (!Thunk.This.isEmpty()) { 1910 Out << "\n [this adjustment: "; 1911 Out << Thunk.This.NonVirtual << " non-virtual"; 1912 1913 if (Thunk.This.VCallOffsetOffset) { 1914 Out << ", " << Thunk.This.VCallOffsetOffset; 1915 Out << " vcall offset offset"; 1916 } 1917 1918 Out << ']'; 1919 } 1920 } 1921 1922 break; 1923 } 1924 1925 case VTableComponent::CK_CompleteDtorPointer: 1926 case VTableComponent::CK_DeletingDtorPointer: { 1927 bool IsComplete = 1928 Component.getKind() == VTableComponent::CK_CompleteDtorPointer; 1929 1930 const CXXDestructorDecl *DD = Component.getDestructorDecl(); 1931 1932 Out << DD->getQualifiedNameAsString(); 1933 if (IsComplete) 1934 Out << "() [complete]"; 1935 else 1936 Out << "() [deleting]"; 1937 1938 if (DD->isPure()) 1939 Out << " [pure]"; 1940 1941 ThunkInfo Thunk = VTableThunks.lookup(I); 1942 if (!Thunk.isEmpty()) { 1943 // If this destructor has a 'this' pointer adjustment, dump it. 1944 if (!Thunk.This.isEmpty()) { 1945 Out << "\n [this adjustment: "; 1946 Out << Thunk.This.NonVirtual << " non-virtual"; 1947 1948 if (Thunk.This.VCallOffsetOffset) { 1949 Out << ", " << Thunk.This.VCallOffsetOffset; 1950 Out << " vcall offset offset"; 1951 } 1952 1953 Out << ']'; 1954 } 1955 } 1956 1957 break; 1958 } 1959 1960 case VTableComponent::CK_UnusedFunctionPointer: { 1961 const CXXMethodDecl *MD = Component.getUnusedFunctionDecl(); 1962 1963 std::string Str = 1964 PredefinedExpr::ComputeName(PredefinedExpr::PrettyFunctionNoVirtual, 1965 MD); 1966 Out << "[unused] " << Str; 1967 if (MD->isPure()) 1968 Out << " [pure]"; 1969 } 1970 1971 } 1972 1973 Out << '\n'; 1974 1975 // Dump the next address point. 1976 uint64_t NextIndex = Index + 1; 1977 if (AddressPointsByIndex.count(NextIndex)) { 1978 if (AddressPointsByIndex.count(NextIndex) == 1) { 1979 const BaseSubobject &Base = 1980 AddressPointsByIndex.find(NextIndex)->second; 1981 1982 Out << " -- (" << Base.getBase()->getQualifiedNameAsString(); 1983 Out << ", " << Base.getBaseOffset().getQuantity(); 1984 Out << ") vtable address --\n"; 1985 } else { 1986 CharUnits BaseOffset = 1987 AddressPointsByIndex.lower_bound(NextIndex)->second.getBaseOffset(); 1988 1989 // We store the class names in a set to get a stable order. 1990 std::set<std::string> ClassNames; 1991 for (std::multimap<uint64_t, BaseSubobject>::const_iterator I = 1992 AddressPointsByIndex.lower_bound(NextIndex), E = 1993 AddressPointsByIndex.upper_bound(NextIndex); I != E; ++I) { 1994 assert(I->second.getBaseOffset() == BaseOffset && 1995 "Invalid base offset!"); 1996 const CXXRecordDecl *RD = I->second.getBase(); 1997 ClassNames.insert(RD->getQualifiedNameAsString()); 1998 } 1999 2000 for (std::set<std::string>::const_iterator I = ClassNames.begin(), 2001 E = ClassNames.end(); I != E; ++I) { 2002 Out << " -- (" << *I; 2003 Out << ", " << BaseOffset.getQuantity() << ") vtable address --\n"; 2004 } 2005 } 2006 } 2007 } 2008 2009 Out << '\n'; 2010 2011 if (isBuildingConstructorVTable()) 2012 return; 2013 2014 if (MostDerivedClass->getNumVBases()) { 2015 // We store the virtual base class names and their offsets in a map to get 2016 // a stable order. 2017 2018 std::map<std::string, CharUnits> ClassNamesAndOffsets; 2019 for (VBaseOffsetOffsetsMapTy::const_iterator I = VBaseOffsetOffsets.begin(), 2020 E = VBaseOffsetOffsets.end(); I != E; ++I) { 2021 std::string ClassName = I->first->getQualifiedNameAsString(); 2022 CharUnits OffsetOffset = I->second; 2023 ClassNamesAndOffsets.insert( 2024 std::make_pair(ClassName, OffsetOffset)); 2025 } 2026 2027 Out << "Virtual base offset offsets for '"; 2028 Out << MostDerivedClass->getQualifiedNameAsString() << "' ("; 2029 Out << ClassNamesAndOffsets.size(); 2030 Out << (ClassNamesAndOffsets.size() == 1 ? " entry" : " entries") << ").\n"; 2031 2032 for (std::map<std::string, CharUnits>::const_iterator I = 2033 ClassNamesAndOffsets.begin(), E = ClassNamesAndOffsets.end(); 2034 I != E; ++I) 2035 Out << " " << I->first << " | " << I->second.getQuantity() << '\n'; 2036 2037 Out << "\n"; 2038 } 2039 2040 if (!Thunks.empty()) { 2041 // We store the method names in a map to get a stable order. 2042 std::map<std::string, const CXXMethodDecl *> MethodNamesAndDecls; 2043 2044 for (ThunksMapTy::const_iterator I = Thunks.begin(), E = Thunks.end(); 2045 I != E; ++I) { 2046 const CXXMethodDecl *MD = I->first; 2047 std::string MethodName = 2048 PredefinedExpr::ComputeName(PredefinedExpr::PrettyFunctionNoVirtual, 2049 MD); 2050 2051 MethodNamesAndDecls.insert(std::make_pair(MethodName, MD)); 2052 } 2053 2054 for (std::map<std::string, const CXXMethodDecl *>::const_iterator I = 2055 MethodNamesAndDecls.begin(), E = MethodNamesAndDecls.end(); 2056 I != E; ++I) { 2057 const std::string &MethodName = I->first; 2058 const CXXMethodDecl *MD = I->second; 2059 2060 ThunkInfoVectorTy ThunksVector = Thunks[MD]; 2061 std::sort(ThunksVector.begin(), ThunksVector.end()); 2062 2063 Out << "Thunks for '" << MethodName << "' (" << ThunksVector.size(); 2064 Out << (ThunksVector.size() == 1 ? " entry" : " entries") << ").\n"; 2065 2066 for (unsigned I = 0, E = ThunksVector.size(); I != E; ++I) { 2067 const ThunkInfo &Thunk = ThunksVector[I]; 2068 2069 Out << llvm::format("%4d | ", I); 2070 2071 // If this function pointer has a return pointer adjustment, dump it. 2072 if (!Thunk.Return.isEmpty()) { 2073 Out << "return adjustment: " << Thunk.This.NonVirtual; 2074 Out << " non-virtual"; 2075 if (Thunk.Return.VBaseOffsetOffset) { 2076 Out << ", " << Thunk.Return.VBaseOffsetOffset; 2077 Out << " vbase offset offset"; 2078 } 2079 2080 if (!Thunk.This.isEmpty()) 2081 Out << "\n "; 2082 } 2083 2084 // If this function pointer has a 'this' pointer adjustment, dump it. 2085 if (!Thunk.This.isEmpty()) { 2086 Out << "this adjustment: "; 2087 Out << Thunk.This.NonVirtual << " non-virtual"; 2088 2089 if (Thunk.This.VCallOffsetOffset) { 2090 Out << ", " << Thunk.This.VCallOffsetOffset; 2091 Out << " vcall offset offset"; 2092 } 2093 } 2094 2095 Out << '\n'; 2096 } 2097 2098 Out << '\n'; 2099 } 2100 } 2101 2102 // Compute the vtable indices for all the member functions. 2103 // Store them in a map keyed by the index so we'll get a sorted table. 2104 std::map<uint64_t, std::string> IndicesMap; 2105 2106 for (CXXRecordDecl::method_iterator i = MostDerivedClass->method_begin(), 2107 e = MostDerivedClass->method_end(); i != e; ++i) { 2108 const CXXMethodDecl *MD = *i; 2109 2110 // We only want virtual member functions. 2111 if (!MD->isVirtual()) 2112 continue; 2113 2114 std::string MethodName = 2115 PredefinedExpr::ComputeName(PredefinedExpr::PrettyFunctionNoVirtual, 2116 MD); 2117 2118 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) { 2119 IndicesMap[VTables.getMethodVTableIndex(GlobalDecl(DD, Dtor_Complete))] = 2120 MethodName + " [complete]"; 2121 IndicesMap[VTables.getMethodVTableIndex(GlobalDecl(DD, Dtor_Deleting))] = 2122 MethodName + " [deleting]"; 2123 } else { 2124 IndicesMap[VTables.getMethodVTableIndex(MD)] = MethodName; 2125 } 2126 } 2127 2128 // Print the vtable indices for all the member functions. 2129 if (!IndicesMap.empty()) { 2130 Out << "VTable indices for '"; 2131 Out << MostDerivedClass->getQualifiedNameAsString(); 2132 Out << "' (" << IndicesMap.size() << " entries).\n"; 2133 2134 for (std::map<uint64_t, std::string>::const_iterator I = IndicesMap.begin(), 2135 E = IndicesMap.end(); I != E; ++I) { 2136 uint64_t VTableIndex = I->first; 2137 const std::string &MethodName = I->second; 2138 2139 Out << llvm::format(" %4" PRIu64 " | ", VTableIndex) << MethodName 2140 << '\n'; 2141 } 2142 } 2143 2144 Out << '\n'; 2145 } 2146 2147 } 2148 2149 VTableLayout::VTableLayout(uint64_t NumVTableComponents, 2150 const VTableComponent *VTableComponents, 2151 uint64_t NumVTableThunks, 2152 const VTableThunkTy *VTableThunks, 2153 const AddressPointsMapTy &AddressPoints) 2154 : NumVTableComponents(NumVTableComponents), 2155 VTableComponents(new VTableComponent[NumVTableComponents]), 2156 NumVTableThunks(NumVTableThunks), 2157 VTableThunks(new VTableThunkTy[NumVTableThunks]), 2158 AddressPoints(AddressPoints) { 2159 std::copy(VTableComponents, VTableComponents+NumVTableComponents, 2160 this->VTableComponents.get()); 2161 std::copy(VTableThunks, VTableThunks+NumVTableThunks, 2162 this->VTableThunks.get()); 2163 } 2164 2165 VTableLayout::~VTableLayout() { } 2166 2167 VTableContext::~VTableContext() { 2168 llvm::DeleteContainerSeconds(VTableLayouts); 2169 } 2170 2171 static void 2172 CollectPrimaryBases(const CXXRecordDecl *RD, ASTContext &Context, 2173 VTableBuilder::PrimaryBasesSetVectorTy &PrimaryBases) { 2174 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); 2175 const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase(); 2176 2177 if (!PrimaryBase) 2178 return; 2179 2180 CollectPrimaryBases(PrimaryBase, Context, PrimaryBases); 2181 2182 if (!PrimaryBases.insert(PrimaryBase)) 2183 llvm_unreachable("Found a duplicate primary base!"); 2184 } 2185 2186 void VTableContext::ComputeMethodVTableIndices(const CXXRecordDecl *RD) { 2187 2188 // Itanium C++ ABI 2.5.2: 2189 // The order of the virtual function pointers in a virtual table is the 2190 // order of declaration of the corresponding member functions in the class. 2191 // 2192 // There is an entry for any virtual function declared in a class, 2193 // whether it is a new function or overrides a base class function, 2194 // unless it overrides a function from the primary base, and conversion 2195 // between their return types does not require an adjustment. 2196 2197 int64_t CurrentIndex = 0; 2198 2199 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); 2200 const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase(); 2201 2202 if (PrimaryBase) { 2203 assert(PrimaryBase->isCompleteDefinition() && 2204 "Should have the definition decl of the primary base!"); 2205 2206 // Since the record decl shares its vtable pointer with the primary base 2207 // we need to start counting at the end of the primary base's vtable. 2208 CurrentIndex = getNumVirtualFunctionPointers(PrimaryBase); 2209 } 2210 2211 // Collect all the primary bases, so we can check whether methods override 2212 // a method from the base. 2213 VTableBuilder::PrimaryBasesSetVectorTy PrimaryBases; 2214 CollectPrimaryBases(RD, Context, PrimaryBases); 2215 2216 const CXXDestructorDecl *ImplicitVirtualDtor = 0; 2217 2218 for (CXXRecordDecl::method_iterator i = RD->method_begin(), 2219 e = RD->method_end(); i != e; ++i) { 2220 const CXXMethodDecl *MD = *i; 2221 2222 // We only want virtual methods. 2223 if (!MD->isVirtual()) 2224 continue; 2225 2226 // Check if this method overrides a method in the primary base. 2227 if (const CXXMethodDecl *OverriddenMD = 2228 FindNearestOverriddenMethod(MD, PrimaryBases)) { 2229 // Check if converting from the return type of the method to the 2230 // return type of the overridden method requires conversion. 2231 if (ComputeReturnAdjustmentBaseOffset(Context, MD, 2232 OverriddenMD).isEmpty()) { 2233 // This index is shared between the index in the vtable of the primary 2234 // base class. 2235 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) { 2236 const CXXDestructorDecl *OverriddenDD = 2237 cast<CXXDestructorDecl>(OverriddenMD); 2238 2239 // Add both the complete and deleting entries. 2240 MethodVTableIndices[GlobalDecl(DD, Dtor_Complete)] = 2241 getMethodVTableIndex(GlobalDecl(OverriddenDD, Dtor_Complete)); 2242 MethodVTableIndices[GlobalDecl(DD, Dtor_Deleting)] = 2243 getMethodVTableIndex(GlobalDecl(OverriddenDD, Dtor_Deleting)); 2244 } else { 2245 MethodVTableIndices[MD] = getMethodVTableIndex(OverriddenMD); 2246 } 2247 2248 // We don't need to add an entry for this method. 2249 continue; 2250 } 2251 } 2252 2253 if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) { 2254 if (MD->isImplicit()) { 2255 assert(!ImplicitVirtualDtor && 2256 "Did already see an implicit virtual dtor!"); 2257 ImplicitVirtualDtor = DD; 2258 continue; 2259 } 2260 2261 // Add the complete dtor. 2262 MethodVTableIndices[GlobalDecl(DD, Dtor_Complete)] = CurrentIndex++; 2263 2264 // Add the deleting dtor. 2265 MethodVTableIndices[GlobalDecl(DD, Dtor_Deleting)] = CurrentIndex++; 2266 } else { 2267 // Add the entry. 2268 MethodVTableIndices[MD] = CurrentIndex++; 2269 } 2270 } 2271 2272 if (ImplicitVirtualDtor) { 2273 // Itanium C++ ABI 2.5.2: 2274 // If a class has an implicitly-defined virtual destructor, 2275 // its entries come after the declared virtual function pointers. 2276 2277 // Add the complete dtor. 2278 MethodVTableIndices[GlobalDecl(ImplicitVirtualDtor, Dtor_Complete)] = 2279 CurrentIndex++; 2280 2281 // Add the deleting dtor. 2282 MethodVTableIndices[GlobalDecl(ImplicitVirtualDtor, Dtor_Deleting)] = 2283 CurrentIndex++; 2284 } 2285 2286 NumVirtualFunctionPointers[RD] = CurrentIndex; 2287 } 2288 2289 uint64_t VTableContext::getNumVirtualFunctionPointers(const CXXRecordDecl *RD) { 2290 llvm::DenseMap<const CXXRecordDecl *, uint64_t>::iterator I = 2291 NumVirtualFunctionPointers.find(RD); 2292 if (I != NumVirtualFunctionPointers.end()) 2293 return I->second; 2294 2295 ComputeMethodVTableIndices(RD); 2296 2297 I = NumVirtualFunctionPointers.find(RD); 2298 assert(I != NumVirtualFunctionPointers.end() && "Did not find entry!"); 2299 return I->second; 2300 } 2301 2302 uint64_t VTableContext::getMethodVTableIndex(GlobalDecl GD) { 2303 MethodVTableIndicesTy::iterator I = MethodVTableIndices.find(GD); 2304 if (I != MethodVTableIndices.end()) 2305 return I->second; 2306 2307 const CXXRecordDecl *RD = cast<CXXMethodDecl>(GD.getDecl())->getParent(); 2308 2309 ComputeMethodVTableIndices(RD); 2310 2311 I = MethodVTableIndices.find(GD); 2312 assert(I != MethodVTableIndices.end() && "Did not find index!"); 2313 return I->second; 2314 } 2315 2316 CharUnits 2317 VTableContext::getVirtualBaseOffsetOffset(const CXXRecordDecl *RD, 2318 const CXXRecordDecl *VBase) { 2319 ClassPairTy ClassPair(RD, VBase); 2320 2321 VirtualBaseClassOffsetOffsetsMapTy::iterator I = 2322 VirtualBaseClassOffsetOffsets.find(ClassPair); 2323 if (I != VirtualBaseClassOffsetOffsets.end()) 2324 return I->second; 2325 2326 VCallAndVBaseOffsetBuilder Builder(RD, RD, /*FinalOverriders=*/0, 2327 BaseSubobject(RD, CharUnits::Zero()), 2328 /*BaseIsVirtual=*/false, 2329 /*OffsetInLayoutClass=*/CharUnits::Zero()); 2330 2331 for (VCallAndVBaseOffsetBuilder::VBaseOffsetOffsetsMapTy::const_iterator I = 2332 Builder.getVBaseOffsetOffsets().begin(), 2333 E = Builder.getVBaseOffsetOffsets().end(); I != E; ++I) { 2334 // Insert all types. 2335 ClassPairTy ClassPair(RD, I->first); 2336 2337 VirtualBaseClassOffsetOffsets.insert( 2338 std::make_pair(ClassPair, I->second)); 2339 } 2340 2341 I = VirtualBaseClassOffsetOffsets.find(ClassPair); 2342 assert(I != VirtualBaseClassOffsetOffsets.end() && "Did not find index!"); 2343 2344 return I->second; 2345 } 2346 2347 static VTableLayout *CreateVTableLayout(const VTableBuilder &Builder) { 2348 SmallVector<VTableLayout::VTableThunkTy, 1> 2349 VTableThunks(Builder.vtable_thunks_begin(), Builder.vtable_thunks_end()); 2350 std::sort(VTableThunks.begin(), VTableThunks.end()); 2351 2352 return new VTableLayout(Builder.getNumVTableComponents(), 2353 Builder.vtable_component_begin(), 2354 VTableThunks.size(), 2355 VTableThunks.data(), 2356 Builder.getAddressPoints()); 2357 } 2358 2359 void VTableContext::ComputeVTableRelatedInformation(const CXXRecordDecl *RD) { 2360 const VTableLayout *&Entry = VTableLayouts[RD]; 2361 2362 // Check if we've computed this information before. 2363 if (Entry) 2364 return; 2365 2366 VTableBuilder Builder(*this, RD, CharUnits::Zero(), 2367 /*MostDerivedClassIsVirtual=*/0, RD); 2368 Entry = CreateVTableLayout(Builder); 2369 2370 // Add the known thunks. 2371 Thunks.insert(Builder.thunks_begin(), Builder.thunks_end()); 2372 2373 // If we don't have the vbase information for this class, insert it. 2374 // getVirtualBaseOffsetOffset will compute it separately without computing 2375 // the rest of the vtable related information. 2376 if (!RD->getNumVBases()) 2377 return; 2378 2379 const RecordType *VBaseRT = 2380 RD->vbases_begin()->getType()->getAs<RecordType>(); 2381 const CXXRecordDecl *VBase = cast<CXXRecordDecl>(VBaseRT->getDecl()); 2382 2383 if (VirtualBaseClassOffsetOffsets.count(std::make_pair(RD, VBase))) 2384 return; 2385 2386 for (VTableBuilder::VBaseOffsetOffsetsMapTy::const_iterator I = 2387 Builder.getVBaseOffsetOffsets().begin(), 2388 E = Builder.getVBaseOffsetOffsets().end(); I != E; ++I) { 2389 // Insert all types. 2390 ClassPairTy ClassPair(RD, I->first); 2391 2392 VirtualBaseClassOffsetOffsets.insert(std::make_pair(ClassPair, I->second)); 2393 } 2394 } 2395 2396 VTableLayout *VTableContext::createConstructionVTableLayout( 2397 const CXXRecordDecl *MostDerivedClass, 2398 CharUnits MostDerivedClassOffset, 2399 bool MostDerivedClassIsVirtual, 2400 const CXXRecordDecl *LayoutClass) { 2401 VTableBuilder Builder(*this, MostDerivedClass, MostDerivedClassOffset, 2402 MostDerivedClassIsVirtual, LayoutClass); 2403 return CreateVTableLayout(Builder); 2404 } 2405