1 //===--- CGBlocks.cpp - Emit LLVM Code for declarations -------------------===// 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 to emit blocks. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "CGBlocks.h" 15 #include "CGDebugInfo.h" 16 #include "CGObjCRuntime.h" 17 #include "CodeGenFunction.h" 18 #include "CodeGenModule.h" 19 #include "clang/AST/DeclObjC.h" 20 #include "llvm/ADT/SmallSet.h" 21 #include "llvm/IR/CallSite.h" 22 #include "llvm/IR/DataLayout.h" 23 #include "llvm/IR/Module.h" 24 #include <algorithm> 25 #include <cstdio> 26 27 using namespace clang; 28 using namespace CodeGen; 29 30 CGBlockInfo::CGBlockInfo(const BlockDecl *block, StringRef name) 31 : Name(name), CXXThisIndex(0), CanBeGlobal(false), NeedsCopyDispose(false), 32 HasCXXObject(false), UsesStret(false), HasCapturedVariableLayout(false), 33 StructureType(nullptr), Block(block), 34 DominatingIP(nullptr) { 35 36 // Skip asm prefix, if any. 'name' is usually taken directly from 37 // the mangled name of the enclosing function. 38 if (!name.empty() && name[0] == '\01') 39 name = name.substr(1); 40 } 41 42 // Anchor the vtable to this translation unit. 43 CodeGenModule::ByrefHelpers::~ByrefHelpers() {} 44 45 /// Build the given block as a global block. 46 static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM, 47 const CGBlockInfo &blockInfo, 48 llvm::Constant *blockFn); 49 50 /// Build the helper function to copy a block. 51 static llvm::Constant *buildCopyHelper(CodeGenModule &CGM, 52 const CGBlockInfo &blockInfo) { 53 return CodeGenFunction(CGM).GenerateCopyHelperFunction(blockInfo); 54 } 55 56 /// Build the helper function to dispose of a block. 57 static llvm::Constant *buildDisposeHelper(CodeGenModule &CGM, 58 const CGBlockInfo &blockInfo) { 59 return CodeGenFunction(CGM).GenerateDestroyHelperFunction(blockInfo); 60 } 61 62 /// buildBlockDescriptor - Build the block descriptor meta-data for a block. 63 /// buildBlockDescriptor is accessed from 5th field of the Block_literal 64 /// meta-data and contains stationary information about the block literal. 65 /// Its definition will have 4 (or optinally 6) words. 66 /// \code 67 /// struct Block_descriptor { 68 /// unsigned long reserved; 69 /// unsigned long size; // size of Block_literal metadata in bytes. 70 /// void *copy_func_helper_decl; // optional copy helper. 71 /// void *destroy_func_decl; // optioanl destructor helper. 72 /// void *block_method_encoding_address; // @encode for block literal signature. 73 /// void *block_layout_info; // encoding of captured block variables. 74 /// }; 75 /// \endcode 76 static llvm::Constant *buildBlockDescriptor(CodeGenModule &CGM, 77 const CGBlockInfo &blockInfo) { 78 ASTContext &C = CGM.getContext(); 79 80 llvm::Type *ulong = CGM.getTypes().ConvertType(C.UnsignedLongTy); 81 llvm::Type *i8p = NULL; 82 if (CGM.getLangOpts().OpenCL) 83 i8p = 84 llvm::Type::getInt8PtrTy( 85 CGM.getLLVMContext(), C.getTargetAddressSpace(LangAS::opencl_constant)); 86 else 87 i8p = CGM.getTypes().ConvertType(C.VoidPtrTy); 88 89 SmallVector<llvm::Constant*, 6> elements; 90 91 // reserved 92 elements.push_back(llvm::ConstantInt::get(ulong, 0)); 93 94 // Size 95 // FIXME: What is the right way to say this doesn't fit? We should give 96 // a user diagnostic in that case. Better fix would be to change the 97 // API to size_t. 98 elements.push_back(llvm::ConstantInt::get(ulong, 99 blockInfo.BlockSize.getQuantity())); 100 101 // Optional copy/dispose helpers. 102 if (blockInfo.NeedsCopyDispose) { 103 // copy_func_helper_decl 104 elements.push_back(buildCopyHelper(CGM, blockInfo)); 105 106 // destroy_func_decl 107 elements.push_back(buildDisposeHelper(CGM, blockInfo)); 108 } 109 110 // Signature. Mandatory ObjC-style method descriptor @encode sequence. 111 std::string typeAtEncoding = 112 CGM.getContext().getObjCEncodingForBlock(blockInfo.getBlockExpr()); 113 elements.push_back(llvm::ConstantExpr::getBitCast( 114 CGM.GetAddrOfConstantCString(typeAtEncoding), i8p)); 115 116 // GC layout. 117 if (C.getLangOpts().ObjC1) { 118 if (CGM.getLangOpts().getGC() != LangOptions::NonGC) 119 elements.push_back(CGM.getObjCRuntime().BuildGCBlockLayout(CGM, blockInfo)); 120 else 121 elements.push_back(CGM.getObjCRuntime().BuildRCBlockLayout(CGM, blockInfo)); 122 } 123 else 124 elements.push_back(llvm::Constant::getNullValue(i8p)); 125 126 llvm::Constant *init = llvm::ConstantStruct::getAnon(elements); 127 128 llvm::GlobalVariable *global = 129 new llvm::GlobalVariable(CGM.getModule(), init->getType(), true, 130 llvm::GlobalValue::InternalLinkage, 131 init, "__block_descriptor_tmp"); 132 133 return llvm::ConstantExpr::getBitCast(global, CGM.getBlockDescriptorType()); 134 } 135 136 /* 137 Purely notional variadic template describing the layout of a block. 138 139 template <class _ResultType, class... _ParamTypes, class... _CaptureTypes> 140 struct Block_literal { 141 /// Initialized to one of: 142 /// extern void *_NSConcreteStackBlock[]; 143 /// extern void *_NSConcreteGlobalBlock[]; 144 /// 145 /// In theory, we could start one off malloc'ed by setting 146 /// BLOCK_NEEDS_FREE, giving it a refcount of 1, and using 147 /// this isa: 148 /// extern void *_NSConcreteMallocBlock[]; 149 struct objc_class *isa; 150 151 /// These are the flags (with corresponding bit number) that the 152 /// compiler is actually supposed to know about. 153 /// 25. BLOCK_HAS_COPY_DISPOSE - indicates that the block 154 /// descriptor provides copy and dispose helper functions 155 /// 26. BLOCK_HAS_CXX_OBJ - indicates that there's a captured 156 /// object with a nontrivial destructor or copy constructor 157 /// 28. BLOCK_IS_GLOBAL - indicates that the block is allocated 158 /// as global memory 159 /// 29. BLOCK_USE_STRET - indicates that the block function 160 /// uses stret, which objc_msgSend needs to know about 161 /// 30. BLOCK_HAS_SIGNATURE - indicates that the block has an 162 /// @encoded signature string 163 /// And we're not supposed to manipulate these: 164 /// 24. BLOCK_NEEDS_FREE - indicates that the block has been moved 165 /// to malloc'ed memory 166 /// 27. BLOCK_IS_GC - indicates that the block has been moved to 167 /// to GC-allocated memory 168 /// Additionally, the bottom 16 bits are a reference count which 169 /// should be zero on the stack. 170 int flags; 171 172 /// Reserved; should be zero-initialized. 173 int reserved; 174 175 /// Function pointer generated from block literal. 176 _ResultType (*invoke)(Block_literal *, _ParamTypes...); 177 178 /// Block description metadata generated from block literal. 179 struct Block_descriptor *block_descriptor; 180 181 /// Captured values follow. 182 _CapturesTypes captures...; 183 }; 184 */ 185 186 /// The number of fields in a block header. 187 const unsigned BlockHeaderSize = 5; 188 189 namespace { 190 /// A chunk of data that we actually have to capture in the block. 191 struct BlockLayoutChunk { 192 CharUnits Alignment; 193 CharUnits Size; 194 Qualifiers::ObjCLifetime Lifetime; 195 const BlockDecl::Capture *Capture; // null for 'this' 196 llvm::Type *Type; 197 198 BlockLayoutChunk(CharUnits align, CharUnits size, 199 Qualifiers::ObjCLifetime lifetime, 200 const BlockDecl::Capture *capture, 201 llvm::Type *type) 202 : Alignment(align), Size(size), Lifetime(lifetime), 203 Capture(capture), Type(type) {} 204 205 /// Tell the block info that this chunk has the given field index. 206 void setIndex(CGBlockInfo &info, unsigned index) { 207 if (!Capture) 208 info.CXXThisIndex = index; 209 else 210 info.Captures[Capture->getVariable()] 211 = CGBlockInfo::Capture::makeIndex(index); 212 } 213 }; 214 215 /// Order by 1) all __strong together 2) next, all byfref together 3) next, 216 /// all __weak together. Preserve descending alignment in all situations. 217 bool operator<(const BlockLayoutChunk &left, const BlockLayoutChunk &right) { 218 CharUnits LeftValue, RightValue; 219 bool LeftByref = left.Capture ? left.Capture->isByRef() : false; 220 bool RightByref = right.Capture ? right.Capture->isByRef() : false; 221 222 if (left.Lifetime == Qualifiers::OCL_Strong && 223 left.Alignment >= right.Alignment) 224 LeftValue = CharUnits::fromQuantity(64); 225 else if (LeftByref && left.Alignment >= right.Alignment) 226 LeftValue = CharUnits::fromQuantity(32); 227 else if (left.Lifetime == Qualifiers::OCL_Weak && 228 left.Alignment >= right.Alignment) 229 LeftValue = CharUnits::fromQuantity(16); 230 else 231 LeftValue = left.Alignment; 232 if (right.Lifetime == Qualifiers::OCL_Strong && 233 right.Alignment >= left.Alignment) 234 RightValue = CharUnits::fromQuantity(64); 235 else if (RightByref && right.Alignment >= left.Alignment) 236 RightValue = CharUnits::fromQuantity(32); 237 else if (right.Lifetime == Qualifiers::OCL_Weak && 238 right.Alignment >= left.Alignment) 239 RightValue = CharUnits::fromQuantity(16); 240 else 241 RightValue = right.Alignment; 242 243 return LeftValue > RightValue; 244 } 245 } 246 247 /// Determines if the given type is safe for constant capture in C++. 248 static bool isSafeForCXXConstantCapture(QualType type) { 249 const RecordType *recordType = 250 type->getBaseElementTypeUnsafe()->getAs<RecordType>(); 251 252 // Only records can be unsafe. 253 if (!recordType) return true; 254 255 const auto *record = cast<CXXRecordDecl>(recordType->getDecl()); 256 257 // Maintain semantics for classes with non-trivial dtors or copy ctors. 258 if (!record->hasTrivialDestructor()) return false; 259 if (record->hasNonTrivialCopyConstructor()) return false; 260 261 // Otherwise, we just have to make sure there aren't any mutable 262 // fields that might have changed since initialization. 263 return !record->hasMutableFields(); 264 } 265 266 /// It is illegal to modify a const object after initialization. 267 /// Therefore, if a const object has a constant initializer, we don't 268 /// actually need to keep storage for it in the block; we'll just 269 /// rematerialize it at the start of the block function. This is 270 /// acceptable because we make no promises about address stability of 271 /// captured variables. 272 static llvm::Constant *tryCaptureAsConstant(CodeGenModule &CGM, 273 CodeGenFunction *CGF, 274 const VarDecl *var) { 275 QualType type = var->getType(); 276 277 // We can only do this if the variable is const. 278 if (!type.isConstQualified()) return nullptr; 279 280 // Furthermore, in C++ we have to worry about mutable fields: 281 // C++ [dcl.type.cv]p4: 282 // Except that any class member declared mutable can be 283 // modified, any attempt to modify a const object during its 284 // lifetime results in undefined behavior. 285 if (CGM.getLangOpts().CPlusPlus && !isSafeForCXXConstantCapture(type)) 286 return nullptr; 287 288 // If the variable doesn't have any initializer (shouldn't this be 289 // invalid?), it's not clear what we should do. Maybe capture as 290 // zero? 291 const Expr *init = var->getInit(); 292 if (!init) return nullptr; 293 294 return CGM.EmitConstantInit(*var, CGF); 295 } 296 297 /// Get the low bit of a nonzero character count. This is the 298 /// alignment of the nth byte if the 0th byte is universally aligned. 299 static CharUnits getLowBit(CharUnits v) { 300 return CharUnits::fromQuantity(v.getQuantity() & (~v.getQuantity() + 1)); 301 } 302 303 static void initializeForBlockHeader(CodeGenModule &CGM, CGBlockInfo &info, 304 SmallVectorImpl<llvm::Type*> &elementTypes) { 305 ASTContext &C = CGM.getContext(); 306 307 // The header is basically a 'struct { void *; int; int; void *; void *; }'. 308 CharUnits ptrSize, ptrAlign, intSize, intAlign; 309 std::tie(ptrSize, ptrAlign) = C.getTypeInfoInChars(C.VoidPtrTy); 310 std::tie(intSize, intAlign) = C.getTypeInfoInChars(C.IntTy); 311 312 // Are there crazy embedded platforms where this isn't true? 313 assert(intSize <= ptrSize && "layout assumptions horribly violated"); 314 315 CharUnits headerSize = ptrSize; 316 if (2 * intSize < ptrAlign) headerSize += ptrSize; 317 else headerSize += 2 * intSize; 318 headerSize += 2 * ptrSize; 319 320 info.BlockAlign = ptrAlign; 321 info.BlockSize = headerSize; 322 323 assert(elementTypes.empty()); 324 llvm::Type *i8p = CGM.getTypes().ConvertType(C.VoidPtrTy); 325 llvm::Type *intTy = CGM.getTypes().ConvertType(C.IntTy); 326 elementTypes.push_back(i8p); 327 elementTypes.push_back(intTy); 328 elementTypes.push_back(intTy); 329 elementTypes.push_back(i8p); 330 elementTypes.push_back(CGM.getBlockDescriptorType()); 331 332 assert(elementTypes.size() == BlockHeaderSize); 333 } 334 335 /// Compute the layout of the given block. Attempts to lay the block 336 /// out with minimal space requirements. 337 static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF, 338 CGBlockInfo &info) { 339 ASTContext &C = CGM.getContext(); 340 const BlockDecl *block = info.getBlockDecl(); 341 342 SmallVector<llvm::Type*, 8> elementTypes; 343 initializeForBlockHeader(CGM, info, elementTypes); 344 345 if (!block->hasCaptures()) { 346 info.StructureType = 347 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); 348 info.CanBeGlobal = true; 349 return; 350 } 351 else if (C.getLangOpts().ObjC1 && 352 CGM.getLangOpts().getGC() == LangOptions::NonGC) 353 info.HasCapturedVariableLayout = true; 354 355 // Collect the layout chunks. 356 SmallVector<BlockLayoutChunk, 16> layout; 357 layout.reserve(block->capturesCXXThis() + 358 (block->capture_end() - block->capture_begin())); 359 360 CharUnits maxFieldAlign; 361 362 // First, 'this'. 363 if (block->capturesCXXThis()) { 364 assert(CGF && CGF->CurFuncDecl && isa<CXXMethodDecl>(CGF->CurFuncDecl) && 365 "Can't capture 'this' outside a method"); 366 QualType thisType = cast<CXXMethodDecl>(CGF->CurFuncDecl)->getThisType(C); 367 368 llvm::Type *llvmType = CGM.getTypes().ConvertType(thisType); 369 std::pair<CharUnits,CharUnits> tinfo 370 = CGM.getContext().getTypeInfoInChars(thisType); 371 maxFieldAlign = std::max(maxFieldAlign, tinfo.second); 372 373 layout.push_back(BlockLayoutChunk(tinfo.second, tinfo.first, 374 Qualifiers::OCL_None, 375 nullptr, llvmType)); 376 } 377 378 // Next, all the block captures. 379 for (const auto &CI : block->captures()) { 380 const VarDecl *variable = CI.getVariable(); 381 382 if (CI.isByRef()) { 383 // We have to copy/dispose of the __block reference. 384 info.NeedsCopyDispose = true; 385 386 // Just use void* instead of a pointer to the byref type. 387 QualType byRefPtrTy = C.VoidPtrTy; 388 389 llvm::Type *llvmType = CGM.getTypes().ConvertType(byRefPtrTy); 390 std::pair<CharUnits,CharUnits> tinfo 391 = CGM.getContext().getTypeInfoInChars(byRefPtrTy); 392 maxFieldAlign = std::max(maxFieldAlign, tinfo.second); 393 394 layout.push_back(BlockLayoutChunk(tinfo.second, tinfo.first, 395 Qualifiers::OCL_None, &CI, llvmType)); 396 continue; 397 } 398 399 // Otherwise, build a layout chunk with the size and alignment of 400 // the declaration. 401 if (llvm::Constant *constant = tryCaptureAsConstant(CGM, CGF, variable)) { 402 info.Captures[variable] = CGBlockInfo::Capture::makeConstant(constant); 403 continue; 404 } 405 406 // If we have a lifetime qualifier, honor it for capture purposes. 407 // That includes *not* copying it if it's __unsafe_unretained. 408 Qualifiers::ObjCLifetime lifetime = 409 variable->getType().getObjCLifetime(); 410 if (lifetime) { 411 switch (lifetime) { 412 case Qualifiers::OCL_None: llvm_unreachable("impossible"); 413 case Qualifiers::OCL_ExplicitNone: 414 case Qualifiers::OCL_Autoreleasing: 415 break; 416 417 case Qualifiers::OCL_Strong: 418 case Qualifiers::OCL_Weak: 419 info.NeedsCopyDispose = true; 420 } 421 422 // Block pointers require copy/dispose. So do Objective-C pointers. 423 } else if (variable->getType()->isObjCRetainableType()) { 424 info.NeedsCopyDispose = true; 425 // used for mrr below. 426 lifetime = Qualifiers::OCL_Strong; 427 428 // So do types that require non-trivial copy construction. 429 } else if (CI.hasCopyExpr()) { 430 info.NeedsCopyDispose = true; 431 info.HasCXXObject = true; 432 433 // And so do types with destructors. 434 } else if (CGM.getLangOpts().CPlusPlus) { 435 if (const CXXRecordDecl *record = 436 variable->getType()->getAsCXXRecordDecl()) { 437 if (!record->hasTrivialDestructor()) { 438 info.HasCXXObject = true; 439 info.NeedsCopyDispose = true; 440 } 441 } 442 } 443 444 QualType VT = variable->getType(); 445 CharUnits size = C.getTypeSizeInChars(VT); 446 CharUnits align = C.getDeclAlign(variable); 447 448 maxFieldAlign = std::max(maxFieldAlign, align); 449 450 llvm::Type *llvmType = 451 CGM.getTypes().ConvertTypeForMem(VT); 452 453 layout.push_back(BlockLayoutChunk(align, size, lifetime, &CI, llvmType)); 454 } 455 456 // If that was everything, we're done here. 457 if (layout.empty()) { 458 info.StructureType = 459 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); 460 info.CanBeGlobal = true; 461 return; 462 } 463 464 // Sort the layout by alignment. We have to use a stable sort here 465 // to get reproducible results. There should probably be an 466 // llvm::array_pod_stable_sort. 467 std::stable_sort(layout.begin(), layout.end()); 468 469 // Needed for blocks layout info. 470 info.BlockHeaderForcedGapOffset = info.BlockSize; 471 info.BlockHeaderForcedGapSize = CharUnits::Zero(); 472 473 CharUnits &blockSize = info.BlockSize; 474 info.BlockAlign = std::max(maxFieldAlign, info.BlockAlign); 475 476 // Assuming that the first byte in the header is maximally aligned, 477 // get the alignment of the first byte following the header. 478 CharUnits endAlign = getLowBit(blockSize); 479 480 // If the end of the header isn't satisfactorily aligned for the 481 // maximum thing, look for things that are okay with the header-end 482 // alignment, and keep appending them until we get something that's 483 // aligned right. This algorithm is only guaranteed optimal if 484 // that condition is satisfied at some point; otherwise we can get 485 // things like: 486 // header // next byte has alignment 4 487 // something_with_size_5; // next byte has alignment 1 488 // something_with_alignment_8; 489 // which has 7 bytes of padding, as opposed to the naive solution 490 // which might have less (?). 491 if (endAlign < maxFieldAlign) { 492 SmallVectorImpl<BlockLayoutChunk>::iterator 493 li = layout.begin() + 1, le = layout.end(); 494 495 // Look for something that the header end is already 496 // satisfactorily aligned for. 497 for (; li != le && endAlign < li->Alignment; ++li) 498 ; 499 500 // If we found something that's naturally aligned for the end of 501 // the header, keep adding things... 502 if (li != le) { 503 SmallVectorImpl<BlockLayoutChunk>::iterator first = li; 504 for (; li != le; ++li) { 505 assert(endAlign >= li->Alignment); 506 507 li->setIndex(info, elementTypes.size()); 508 elementTypes.push_back(li->Type); 509 blockSize += li->Size; 510 endAlign = getLowBit(blockSize); 511 512 // ...until we get to the alignment of the maximum field. 513 if (endAlign >= maxFieldAlign) { 514 if (li == first) { 515 // No user field was appended. So, a gap was added. 516 // Save total gap size for use in block layout bit map. 517 info.BlockHeaderForcedGapSize = li->Size; 518 } 519 break; 520 } 521 } 522 // Don't re-append everything we just appended. 523 layout.erase(first, li); 524 } 525 } 526 527 assert(endAlign == getLowBit(blockSize)); 528 529 // At this point, we just have to add padding if the end align still 530 // isn't aligned right. 531 if (endAlign < maxFieldAlign) { 532 CharUnits newBlockSize = blockSize.RoundUpToAlignment(maxFieldAlign); 533 CharUnits padding = newBlockSize - blockSize; 534 535 elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty, 536 padding.getQuantity())); 537 blockSize = newBlockSize; 538 endAlign = getLowBit(blockSize); // might be > maxFieldAlign 539 } 540 541 assert(endAlign >= maxFieldAlign); 542 assert(endAlign == getLowBit(blockSize)); 543 // Slam everything else on now. This works because they have 544 // strictly decreasing alignment and we expect that size is always a 545 // multiple of alignment. 546 for (SmallVectorImpl<BlockLayoutChunk>::iterator 547 li = layout.begin(), le = layout.end(); li != le; ++li) { 548 if (endAlign < li->Alignment) { 549 // size may not be multiple of alignment. This can only happen with 550 // an over-aligned variable. We will be adding a padding field to 551 // make the size be multiple of alignment. 552 CharUnits padding = li->Alignment - endAlign; 553 elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty, 554 padding.getQuantity())); 555 blockSize += padding; 556 endAlign = getLowBit(blockSize); 557 } 558 assert(endAlign >= li->Alignment); 559 li->setIndex(info, elementTypes.size()); 560 elementTypes.push_back(li->Type); 561 blockSize += li->Size; 562 endAlign = getLowBit(blockSize); 563 } 564 565 info.StructureType = 566 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); 567 } 568 569 /// Enter the scope of a block. This should be run at the entrance to 570 /// a full-expression so that the block's cleanups are pushed at the 571 /// right place in the stack. 572 static void enterBlockScope(CodeGenFunction &CGF, BlockDecl *block) { 573 assert(CGF.HaveInsertPoint()); 574 575 // Allocate the block info and place it at the head of the list. 576 CGBlockInfo &blockInfo = 577 *new CGBlockInfo(block, CGF.CurFn->getName()); 578 blockInfo.NextBlockInfo = CGF.FirstBlockInfo; 579 CGF.FirstBlockInfo = &blockInfo; 580 581 // Compute information about the layout, etc., of this block, 582 // pushing cleanups as necessary. 583 computeBlockInfo(CGF.CGM, &CGF, blockInfo); 584 585 // Nothing else to do if it can be global. 586 if (blockInfo.CanBeGlobal) return; 587 588 // Make the allocation for the block. 589 blockInfo.Address = 590 CGF.CreateTempAlloca(blockInfo.StructureType, "block"); 591 blockInfo.Address->setAlignment(blockInfo.BlockAlign.getQuantity()); 592 593 // If there are cleanups to emit, enter them (but inactive). 594 if (!blockInfo.NeedsCopyDispose) return; 595 596 // Walk through the captures (in order) and find the ones not 597 // captured by constant. 598 for (const auto &CI : block->captures()) { 599 // Ignore __block captures; there's nothing special in the 600 // on-stack block that we need to do for them. 601 if (CI.isByRef()) continue; 602 603 // Ignore variables that are constant-captured. 604 const VarDecl *variable = CI.getVariable(); 605 CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 606 if (capture.isConstant()) continue; 607 608 // Ignore objects that aren't destructed. 609 QualType::DestructionKind dtorKind = 610 variable->getType().isDestructedType(); 611 if (dtorKind == QualType::DK_none) continue; 612 613 CodeGenFunction::Destroyer *destroyer; 614 615 // Block captures count as local values and have imprecise semantics. 616 // They also can't be arrays, so need to worry about that. 617 if (dtorKind == QualType::DK_objc_strong_lifetime) { 618 destroyer = CodeGenFunction::destroyARCStrongImprecise; 619 } else { 620 destroyer = CGF.getDestroyer(dtorKind); 621 } 622 623 // GEP down to the address. 624 llvm::Value *addr = CGF.Builder.CreateStructGEP( 625 blockInfo.StructureType, blockInfo.Address, capture.getIndex()); 626 627 // We can use that GEP as the dominating IP. 628 if (!blockInfo.DominatingIP) 629 blockInfo.DominatingIP = cast<llvm::Instruction>(addr); 630 631 CleanupKind cleanupKind = InactiveNormalCleanup; 632 bool useArrayEHCleanup = CGF.needsEHCleanup(dtorKind); 633 if (useArrayEHCleanup) 634 cleanupKind = InactiveNormalAndEHCleanup; 635 636 CGF.pushDestroy(cleanupKind, addr, variable->getType(), 637 destroyer, useArrayEHCleanup); 638 639 // Remember where that cleanup was. 640 capture.setCleanup(CGF.EHStack.stable_begin()); 641 } 642 } 643 644 /// Enter a full-expression with a non-trivial number of objects to 645 /// clean up. This is in this file because, at the moment, the only 646 /// kind of cleanup object is a BlockDecl*. 647 void CodeGenFunction::enterNonTrivialFullExpression(const ExprWithCleanups *E) { 648 assert(E->getNumObjects() != 0); 649 ArrayRef<ExprWithCleanups::CleanupObject> cleanups = E->getObjects(); 650 for (ArrayRef<ExprWithCleanups::CleanupObject>::iterator 651 i = cleanups.begin(), e = cleanups.end(); i != e; ++i) { 652 enterBlockScope(*this, *i); 653 } 654 } 655 656 /// Find the layout for the given block in a linked list and remove it. 657 static CGBlockInfo *findAndRemoveBlockInfo(CGBlockInfo **head, 658 const BlockDecl *block) { 659 while (true) { 660 assert(head && *head); 661 CGBlockInfo *cur = *head; 662 663 // If this is the block we're looking for, splice it out of the list. 664 if (cur->getBlockDecl() == block) { 665 *head = cur->NextBlockInfo; 666 return cur; 667 } 668 669 head = &cur->NextBlockInfo; 670 } 671 } 672 673 /// Destroy a chain of block layouts. 674 void CodeGenFunction::destroyBlockInfos(CGBlockInfo *head) { 675 assert(head && "destroying an empty chain"); 676 do { 677 CGBlockInfo *cur = head; 678 head = cur->NextBlockInfo; 679 delete cur; 680 } while (head != nullptr); 681 } 682 683 /// Emit a block literal expression in the current function. 684 llvm::Value *CodeGenFunction::EmitBlockLiteral(const BlockExpr *blockExpr) { 685 // If the block has no captures, we won't have a pre-computed 686 // layout for it. 687 if (!blockExpr->getBlockDecl()->hasCaptures()) { 688 CGBlockInfo blockInfo(blockExpr->getBlockDecl(), CurFn->getName()); 689 computeBlockInfo(CGM, this, blockInfo); 690 blockInfo.BlockExpression = blockExpr; 691 return EmitBlockLiteral(blockInfo); 692 } 693 694 // Find the block info for this block and take ownership of it. 695 std::unique_ptr<CGBlockInfo> blockInfo; 696 blockInfo.reset(findAndRemoveBlockInfo(&FirstBlockInfo, 697 blockExpr->getBlockDecl())); 698 699 blockInfo->BlockExpression = blockExpr; 700 return EmitBlockLiteral(*blockInfo); 701 } 702 703 llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo) { 704 // Using the computed layout, generate the actual block function. 705 bool isLambdaConv = blockInfo.getBlockDecl()->isConversionFromLambda(); 706 llvm::Constant *blockFn 707 = CodeGenFunction(CGM, true).GenerateBlockFunction(CurGD, blockInfo, 708 LocalDeclMap, 709 isLambdaConv); 710 blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy); 711 712 // If there is nothing to capture, we can emit this as a global block. 713 if (blockInfo.CanBeGlobal) 714 return buildGlobalBlock(CGM, blockInfo, blockFn); 715 716 // Otherwise, we have to emit this as a local block. 717 718 llvm::Constant *isa = CGM.getNSConcreteStackBlock(); 719 isa = llvm::ConstantExpr::getBitCast(isa, VoidPtrTy); 720 721 // Build the block descriptor. 722 llvm::Constant *descriptor = buildBlockDescriptor(CGM, blockInfo); 723 724 llvm::Type *blockTy = blockInfo.StructureType; 725 llvm::AllocaInst *blockAddr = blockInfo.Address; 726 assert(blockAddr && "block has no address!"); 727 728 // Compute the initial on-stack block flags. 729 BlockFlags flags = BLOCK_HAS_SIGNATURE; 730 if (blockInfo.HasCapturedVariableLayout) flags |= BLOCK_HAS_EXTENDED_LAYOUT; 731 if (blockInfo.NeedsCopyDispose) flags |= BLOCK_HAS_COPY_DISPOSE; 732 if (blockInfo.HasCXXObject) flags |= BLOCK_HAS_CXX_OBJ; 733 if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET; 734 735 // Initialize the block literal. 736 Builder.CreateStore( 737 isa, Builder.CreateStructGEP(blockTy, blockAddr, 0, "block.isa")); 738 Builder.CreateStore( 739 llvm::ConstantInt::get(IntTy, flags.getBitMask()), 740 Builder.CreateStructGEP(blockTy, blockAddr, 1, "block.flags")); 741 Builder.CreateStore( 742 llvm::ConstantInt::get(IntTy, 0), 743 Builder.CreateStructGEP(blockTy, blockAddr, 2, "block.reserved")); 744 Builder.CreateStore( 745 blockFn, Builder.CreateStructGEP(blockTy, blockAddr, 3, "block.invoke")); 746 Builder.CreateStore(descriptor, Builder.CreateStructGEP(blockTy, blockAddr, 4, 747 "block.descriptor")); 748 749 // Finally, capture all the values into the block. 750 const BlockDecl *blockDecl = blockInfo.getBlockDecl(); 751 752 // First, 'this'. 753 if (blockDecl->capturesCXXThis()) { 754 llvm::Value *addr = Builder.CreateStructGEP( 755 blockTy, blockAddr, blockInfo.CXXThisIndex, "block.captured-this.addr"); 756 Builder.CreateStore(LoadCXXThis(), addr); 757 } 758 759 // Next, captured variables. 760 for (const auto &CI : blockDecl->captures()) { 761 const VarDecl *variable = CI.getVariable(); 762 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 763 764 // Ignore constant captures. 765 if (capture.isConstant()) continue; 766 767 QualType type = variable->getType(); 768 CharUnits align = getContext().getDeclAlign(variable); 769 770 // This will be a [[type]]*, except that a byref entry will just be 771 // an i8**. 772 llvm::Value *blockField = Builder.CreateStructGEP( 773 blockTy, blockAddr, capture.getIndex(), "block.captured"); 774 775 // Compute the address of the thing we're going to move into the 776 // block literal. 777 llvm::Value *src; 778 if (BlockInfo && CI.isNested()) { 779 // We need to use the capture from the enclosing block. 780 const CGBlockInfo::Capture &enclosingCapture = 781 BlockInfo->getCapture(variable); 782 783 // This is a [[type]]*, except that a byref entry wil just be an i8**. 784 src = Builder.CreateStructGEP(BlockInfo->StructureType, LoadBlockStruct(), 785 enclosingCapture.getIndex(), 786 "block.capture.addr"); 787 } else if (blockDecl->isConversionFromLambda()) { 788 // The lambda capture in a lambda's conversion-to-block-pointer is 789 // special; we'll simply emit it directly. 790 src = nullptr; 791 } else { 792 // Just look it up in the locals map, which will give us back a 793 // [[type]]*. If that doesn't work, do the more elaborate DRE 794 // emission. 795 src = LocalDeclMap.lookup(variable); 796 if (!src) { 797 DeclRefExpr declRef( 798 const_cast<VarDecl *>(variable), 799 /*RefersToEnclosingVariableOrCapture*/ CI.isNested(), type, 800 VK_LValue, SourceLocation()); 801 src = EmitDeclRefLValue(&declRef).getAddress(); 802 } 803 } 804 805 // For byrefs, we just write the pointer to the byref struct into 806 // the block field. There's no need to chase the forwarding 807 // pointer at this point, since we're building something that will 808 // live a shorter life than the stack byref anyway. 809 if (CI.isByRef()) { 810 // Get a void* that points to the byref struct. 811 if (CI.isNested()) 812 src = Builder.CreateAlignedLoad(src, align.getQuantity(), 813 "byref.capture"); 814 else 815 src = Builder.CreateBitCast(src, VoidPtrTy); 816 817 // Write that void* into the capture field. 818 Builder.CreateAlignedStore(src, blockField, align.getQuantity()); 819 820 // If we have a copy constructor, evaluate that into the block field. 821 } else if (const Expr *copyExpr = CI.getCopyExpr()) { 822 if (blockDecl->isConversionFromLambda()) { 823 // If we have a lambda conversion, emit the expression 824 // directly into the block instead. 825 AggValueSlot Slot = 826 AggValueSlot::forAddr(blockField, align, Qualifiers(), 827 AggValueSlot::IsDestructed, 828 AggValueSlot::DoesNotNeedGCBarriers, 829 AggValueSlot::IsNotAliased); 830 EmitAggExpr(copyExpr, Slot); 831 } else { 832 EmitSynthesizedCXXCopyCtor(blockField, src, copyExpr); 833 } 834 835 // If it's a reference variable, copy the reference into the block field. 836 } else if (type->isReferenceType()) { 837 llvm::Value *ref = 838 Builder.CreateAlignedLoad(src, align.getQuantity(), "ref.val"); 839 Builder.CreateAlignedStore(ref, blockField, align.getQuantity()); 840 841 // If this is an ARC __strong block-pointer variable, don't do a 842 // block copy. 843 // 844 // TODO: this can be generalized into the normal initialization logic: 845 // we should never need to do a block-copy when initializing a local 846 // variable, because the local variable's lifetime should be strictly 847 // contained within the stack block's. 848 } else if (type.getObjCLifetime() == Qualifiers::OCL_Strong && 849 type->isBlockPointerType()) { 850 // Load the block and do a simple retain. 851 LValue srcLV = MakeAddrLValue(src, type, align); 852 llvm::Value *value = EmitLoadOfScalar(srcLV, SourceLocation()); 853 value = EmitARCRetainNonBlock(value); 854 855 // Do a primitive store to the block field. 856 LValue destLV = MakeAddrLValue(blockField, type, align); 857 EmitStoreOfScalar(value, destLV, /*init*/ true); 858 859 // Otherwise, fake up a POD copy into the block field. 860 } else { 861 // Fake up a new variable so that EmitScalarInit doesn't think 862 // we're referring to the variable in its own initializer. 863 ImplicitParamDecl blockFieldPseudoVar(getContext(), /*DC*/ nullptr, 864 SourceLocation(), /*name*/ nullptr, 865 type); 866 867 // We use one of these or the other depending on whether the 868 // reference is nested. 869 DeclRefExpr declRef(const_cast<VarDecl *>(variable), 870 /*RefersToEnclosingVariableOrCapture*/ CI.isNested(), 871 type, VK_LValue, SourceLocation()); 872 873 ImplicitCastExpr l2r(ImplicitCastExpr::OnStack, type, CK_LValueToRValue, 874 &declRef, VK_RValue); 875 // FIXME: Pass a specific location for the expr init so that the store is 876 // attributed to a reasonable location - otherwise it may be attributed to 877 // locations of subexpressions in the initialization. 878 EmitExprAsInit(&l2r, &blockFieldPseudoVar, 879 MakeAddrLValue(blockField, type, align), 880 /*captured by init*/ false); 881 } 882 883 // Activate the cleanup if layout pushed one. 884 if (!CI.isByRef()) { 885 EHScopeStack::stable_iterator cleanup = capture.getCleanup(); 886 if (cleanup.isValid()) 887 ActivateCleanupBlock(cleanup, blockInfo.DominatingIP); 888 } 889 } 890 891 // Cast to the converted block-pointer type, which happens (somewhat 892 // unfortunately) to be a pointer to function type. 893 llvm::Value *result = 894 Builder.CreateBitCast(blockAddr, 895 ConvertType(blockInfo.getBlockExpr()->getType())); 896 897 return result; 898 } 899 900 901 llvm::Type *CodeGenModule::getBlockDescriptorType() { 902 if (BlockDescriptorType) 903 return BlockDescriptorType; 904 905 llvm::Type *UnsignedLongTy = 906 getTypes().ConvertType(getContext().UnsignedLongTy); 907 908 // struct __block_descriptor { 909 // unsigned long reserved; 910 // unsigned long block_size; 911 // 912 // // later, the following will be added 913 // 914 // struct { 915 // void (*copyHelper)(); 916 // void (*copyHelper)(); 917 // } helpers; // !!! optional 918 // 919 // const char *signature; // the block signature 920 // const char *layout; // reserved 921 // }; 922 BlockDescriptorType = 923 llvm::StructType::create("struct.__block_descriptor", 924 UnsignedLongTy, UnsignedLongTy, nullptr); 925 926 // Now form a pointer to that. 927 BlockDescriptorType = llvm::PointerType::getUnqual(BlockDescriptorType); 928 return BlockDescriptorType; 929 } 930 931 llvm::Type *CodeGenModule::getGenericBlockLiteralType() { 932 if (GenericBlockLiteralType) 933 return GenericBlockLiteralType; 934 935 llvm::Type *BlockDescPtrTy = getBlockDescriptorType(); 936 937 // struct __block_literal_generic { 938 // void *__isa; 939 // int __flags; 940 // int __reserved; 941 // void (*__invoke)(void *); 942 // struct __block_descriptor *__descriptor; 943 // }; 944 GenericBlockLiteralType = 945 llvm::StructType::create("struct.__block_literal_generic", 946 VoidPtrTy, IntTy, IntTy, VoidPtrTy, 947 BlockDescPtrTy, nullptr); 948 949 return GenericBlockLiteralType; 950 } 951 952 953 RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr *E, 954 ReturnValueSlot ReturnValue) { 955 const BlockPointerType *BPT = 956 E->getCallee()->getType()->getAs<BlockPointerType>(); 957 958 llvm::Value *Callee = EmitScalarExpr(E->getCallee()); 959 960 // Get a pointer to the generic block literal. 961 llvm::Type *BlockLiteralTy = 962 llvm::PointerType::getUnqual(CGM.getGenericBlockLiteralType()); 963 964 // Bitcast the callee to a block literal. 965 llvm::Value *BlockLiteral = 966 Builder.CreateBitCast(Callee, BlockLiteralTy, "block.literal"); 967 968 // Get the function pointer from the literal. 969 llvm::Value *FuncPtr = Builder.CreateStructGEP( 970 CGM.getGenericBlockLiteralType(), BlockLiteral, 3); 971 972 BlockLiteral = Builder.CreateBitCast(BlockLiteral, VoidPtrTy); 973 974 // Add the block literal. 975 CallArgList Args; 976 Args.add(RValue::get(BlockLiteral), getContext().VoidPtrTy); 977 978 QualType FnType = BPT->getPointeeType(); 979 980 // And the rest of the arguments. 981 EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(), 982 E->arg_begin(), E->arg_end()); 983 984 // Load the function. 985 llvm::Value *Func = Builder.CreateLoad(FuncPtr); 986 987 const FunctionType *FuncTy = FnType->castAs<FunctionType>(); 988 const CGFunctionInfo &FnInfo = 989 CGM.getTypes().arrangeBlockFunctionCall(Args, FuncTy); 990 991 // Cast the function pointer to the right type. 992 llvm::Type *BlockFTy = CGM.getTypes().GetFunctionType(FnInfo); 993 994 llvm::Type *BlockFTyPtr = llvm::PointerType::getUnqual(BlockFTy); 995 Func = Builder.CreateBitCast(Func, BlockFTyPtr); 996 997 // And call the block. 998 return EmitCall(FnInfo, Func, ReturnValue, Args); 999 } 1000 1001 llvm::Value *CodeGenFunction::GetAddrOfBlockDecl(const VarDecl *variable, 1002 bool isByRef) { 1003 assert(BlockInfo && "evaluating block ref without block information?"); 1004 const CGBlockInfo::Capture &capture = BlockInfo->getCapture(variable); 1005 1006 // Handle constant captures. 1007 if (capture.isConstant()) return LocalDeclMap[variable]; 1008 1009 llvm::Value *addr = 1010 Builder.CreateStructGEP(BlockInfo->StructureType, LoadBlockStruct(), 1011 capture.getIndex(), "block.capture.addr"); 1012 1013 if (isByRef) { 1014 // addr should be a void** right now. Load, then cast the result 1015 // to byref*. 1016 1017 addr = Builder.CreateLoad(addr); 1018 auto *byrefType = BuildByRefType(variable); 1019 llvm::PointerType *byrefPointerType = llvm::PointerType::get(byrefType, 0); 1020 addr = Builder.CreateBitCast(addr, byrefPointerType, 1021 "byref.addr"); 1022 1023 // Follow the forwarding pointer. 1024 addr = Builder.CreateStructGEP(byrefType, addr, 1, "byref.forwarding"); 1025 addr = Builder.CreateLoad(addr, "byref.addr.forwarded"); 1026 1027 // Cast back to byref* and GEP over to the actual object. 1028 addr = Builder.CreateBitCast(addr, byrefPointerType); 1029 addr = Builder.CreateStructGEP(byrefType, addr, 1030 getByRefValueLLVMField(variable).second, 1031 variable->getNameAsString()); 1032 } 1033 1034 if (variable->getType()->isReferenceType()) 1035 addr = Builder.CreateLoad(addr, "ref.tmp"); 1036 1037 return addr; 1038 } 1039 1040 llvm::Constant * 1041 CodeGenModule::GetAddrOfGlobalBlock(const BlockExpr *blockExpr, 1042 const char *name) { 1043 CGBlockInfo blockInfo(blockExpr->getBlockDecl(), name); 1044 blockInfo.BlockExpression = blockExpr; 1045 1046 // Compute information about the layout, etc., of this block. 1047 computeBlockInfo(*this, nullptr, blockInfo); 1048 1049 // Using that metadata, generate the actual block function. 1050 llvm::Constant *blockFn; 1051 { 1052 llvm::DenseMap<const Decl*, llvm::Value*> LocalDeclMap; 1053 blockFn = CodeGenFunction(*this).GenerateBlockFunction(GlobalDecl(), 1054 blockInfo, 1055 LocalDeclMap, 1056 false); 1057 } 1058 blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy); 1059 1060 return buildGlobalBlock(*this, blockInfo, blockFn); 1061 } 1062 1063 static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM, 1064 const CGBlockInfo &blockInfo, 1065 llvm::Constant *blockFn) { 1066 assert(blockInfo.CanBeGlobal); 1067 1068 // Generate the constants for the block literal initializer. 1069 llvm::Constant *fields[BlockHeaderSize]; 1070 1071 // isa 1072 fields[0] = CGM.getNSConcreteGlobalBlock(); 1073 1074 // __flags 1075 BlockFlags flags = BLOCK_IS_GLOBAL | BLOCK_HAS_SIGNATURE; 1076 if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET; 1077 1078 fields[1] = llvm::ConstantInt::get(CGM.IntTy, flags.getBitMask()); 1079 1080 // Reserved 1081 fields[2] = llvm::Constant::getNullValue(CGM.IntTy); 1082 1083 // Function 1084 fields[3] = blockFn; 1085 1086 // Descriptor 1087 fields[4] = buildBlockDescriptor(CGM, blockInfo); 1088 1089 llvm::Constant *init = llvm::ConstantStruct::getAnon(fields); 1090 1091 llvm::GlobalVariable *literal = 1092 new llvm::GlobalVariable(CGM.getModule(), 1093 init->getType(), 1094 /*constant*/ true, 1095 llvm::GlobalVariable::InternalLinkage, 1096 init, 1097 "__block_literal_global"); 1098 literal->setAlignment(blockInfo.BlockAlign.getQuantity()); 1099 1100 // Return a constant of the appropriately-casted type. 1101 llvm::Type *requiredType = 1102 CGM.getTypes().ConvertType(blockInfo.getBlockExpr()->getType()); 1103 return llvm::ConstantExpr::getBitCast(literal, requiredType); 1104 } 1105 1106 llvm::Function * 1107 CodeGenFunction::GenerateBlockFunction(GlobalDecl GD, 1108 const CGBlockInfo &blockInfo, 1109 const DeclMapTy &ldm, 1110 bool IsLambdaConversionToBlock) { 1111 const BlockDecl *blockDecl = blockInfo.getBlockDecl(); 1112 1113 CurGD = GD; 1114 1115 CurEHLocation = blockInfo.getBlockExpr()->getLocEnd(); 1116 1117 BlockInfo = &blockInfo; 1118 1119 // Arrange for local static and local extern declarations to appear 1120 // to be local to this function as well, in case they're directly 1121 // referenced in a block. 1122 for (DeclMapTy::const_iterator i = ldm.begin(), e = ldm.end(); i != e; ++i) { 1123 const auto *var = dyn_cast<VarDecl>(i->first); 1124 if (var && !var->hasLocalStorage()) 1125 LocalDeclMap[var] = i->second; 1126 } 1127 1128 // Begin building the function declaration. 1129 1130 // Build the argument list. 1131 FunctionArgList args; 1132 1133 // The first argument is the block pointer. Just take it as a void* 1134 // and cast it later. 1135 QualType selfTy = getContext().VoidPtrTy; 1136 IdentifierInfo *II = &CGM.getContext().Idents.get(".block_descriptor"); 1137 1138 ImplicitParamDecl selfDecl(getContext(), const_cast<BlockDecl*>(blockDecl), 1139 SourceLocation(), II, selfTy); 1140 args.push_back(&selfDecl); 1141 1142 // Now add the rest of the parameters. 1143 args.append(blockDecl->param_begin(), blockDecl->param_end()); 1144 1145 // Create the function declaration. 1146 const FunctionProtoType *fnType = blockInfo.getBlockExpr()->getFunctionType(); 1147 const CGFunctionInfo &fnInfo = CGM.getTypes().arrangeFreeFunctionDeclaration( 1148 fnType->getReturnType(), args, fnType->getExtInfo(), 1149 fnType->isVariadic()); 1150 if (CGM.ReturnSlotInterferesWithArgs(fnInfo)) 1151 blockInfo.UsesStret = true; 1152 1153 llvm::FunctionType *fnLLVMType = CGM.getTypes().GetFunctionType(fnInfo); 1154 1155 StringRef name = CGM.getBlockMangledName(GD, blockDecl); 1156 llvm::Function *fn = llvm::Function::Create( 1157 fnLLVMType, llvm::GlobalValue::InternalLinkage, name, &CGM.getModule()); 1158 CGM.SetInternalFunctionAttributes(blockDecl, fn, fnInfo); 1159 1160 // Begin generating the function. 1161 StartFunction(blockDecl, fnType->getReturnType(), fn, fnInfo, args, 1162 blockDecl->getLocation(), 1163 blockInfo.getBlockExpr()->getBody()->getLocStart()); 1164 1165 // Okay. Undo some of what StartFunction did. 1166 1167 // Pull the 'self' reference out of the local decl map. 1168 llvm::Value *blockAddr = LocalDeclMap[&selfDecl]; 1169 LocalDeclMap.erase(&selfDecl); 1170 BlockPointer = Builder.CreateBitCast(blockAddr, 1171 blockInfo.StructureType->getPointerTo(), 1172 "block"); 1173 // At -O0 we generate an explicit alloca for the BlockPointer, so the RA 1174 // won't delete the dbg.declare intrinsics for captured variables. 1175 llvm::Value *BlockPointerDbgLoc = BlockPointer; 1176 if (CGM.getCodeGenOpts().OptimizationLevel == 0) { 1177 // Allocate a stack slot for it, so we can point the debugger to it 1178 llvm::AllocaInst *Alloca = CreateTempAlloca(BlockPointer->getType(), 1179 "block.addr"); 1180 unsigned Align = getContext().getDeclAlign(&selfDecl).getQuantity(); 1181 Alloca->setAlignment(Align); 1182 // Set the DebugLocation to empty, so the store is recognized as a 1183 // frame setup instruction by llvm::DwarfDebug::beginFunction(). 1184 auto NL = ApplyDebugLocation::CreateEmpty(*this); 1185 Builder.CreateAlignedStore(BlockPointer, Alloca, Align); 1186 BlockPointerDbgLoc = Alloca; 1187 } 1188 1189 // If we have a C++ 'this' reference, go ahead and force it into 1190 // existence now. 1191 if (blockDecl->capturesCXXThis()) { 1192 llvm::Value *addr = 1193 Builder.CreateStructGEP(blockInfo.StructureType, BlockPointer, 1194 blockInfo.CXXThisIndex, "block.captured-this"); 1195 CXXThisValue = Builder.CreateLoad(addr, "this"); 1196 } 1197 1198 // Also force all the constant captures. 1199 for (const auto &CI : blockDecl->captures()) { 1200 const VarDecl *variable = CI.getVariable(); 1201 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 1202 if (!capture.isConstant()) continue; 1203 1204 unsigned align = getContext().getDeclAlign(variable).getQuantity(); 1205 1206 llvm::AllocaInst *alloca = 1207 CreateMemTemp(variable->getType(), "block.captured-const"); 1208 alloca->setAlignment(align); 1209 1210 Builder.CreateAlignedStore(capture.getConstant(), alloca, align); 1211 1212 LocalDeclMap[variable] = alloca; 1213 } 1214 1215 // Save a spot to insert the debug information for all the DeclRefExprs. 1216 llvm::BasicBlock *entry = Builder.GetInsertBlock(); 1217 llvm::BasicBlock::iterator entry_ptr = Builder.GetInsertPoint(); 1218 --entry_ptr; 1219 1220 if (IsLambdaConversionToBlock) 1221 EmitLambdaBlockInvokeBody(); 1222 else { 1223 PGO.assignRegionCounters(blockDecl, fn); 1224 RegionCounter Cnt = getPGORegionCounter(blockDecl->getBody()); 1225 Cnt.beginRegion(Builder); 1226 EmitStmt(blockDecl->getBody()); 1227 } 1228 1229 // Remember where we were... 1230 llvm::BasicBlock *resume = Builder.GetInsertBlock(); 1231 1232 // Go back to the entry. 1233 ++entry_ptr; 1234 Builder.SetInsertPoint(entry, entry_ptr); 1235 1236 // Emit debug information for all the DeclRefExprs. 1237 // FIXME: also for 'this' 1238 if (CGDebugInfo *DI = getDebugInfo()) { 1239 for (const auto &CI : blockDecl->captures()) { 1240 const VarDecl *variable = CI.getVariable(); 1241 DI->EmitLocation(Builder, variable->getLocation()); 1242 1243 if (CGM.getCodeGenOpts().getDebugInfo() 1244 >= CodeGenOptions::LimitedDebugInfo) { 1245 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 1246 if (capture.isConstant()) { 1247 DI->EmitDeclareOfAutoVariable(variable, LocalDeclMap[variable], 1248 Builder); 1249 continue; 1250 } 1251 1252 DI->EmitDeclareOfBlockDeclRefVariable(variable, BlockPointerDbgLoc, 1253 Builder, blockInfo, 1254 entry_ptr == entry->end() 1255 ? nullptr : entry_ptr); 1256 } 1257 } 1258 // Recover location if it was changed in the above loop. 1259 DI->EmitLocation(Builder, 1260 cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc()); 1261 } 1262 1263 // And resume where we left off. 1264 if (resume == nullptr) 1265 Builder.ClearInsertionPoint(); 1266 else 1267 Builder.SetInsertPoint(resume); 1268 1269 FinishFunction(cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc()); 1270 1271 return fn; 1272 } 1273 1274 /* 1275 notes.push_back(HelperInfo()); 1276 HelperInfo ¬e = notes.back(); 1277 note.index = capture.getIndex(); 1278 note.RequiresCopying = (ci->hasCopyExpr() || BlockRequiresCopying(type)); 1279 note.cxxbar_import = ci->getCopyExpr(); 1280 1281 if (ci->isByRef()) { 1282 note.flag = BLOCK_FIELD_IS_BYREF; 1283 if (type.isObjCGCWeak()) 1284 note.flag |= BLOCK_FIELD_IS_WEAK; 1285 } else if (type->isBlockPointerType()) { 1286 note.flag = BLOCK_FIELD_IS_BLOCK; 1287 } else { 1288 note.flag = BLOCK_FIELD_IS_OBJECT; 1289 } 1290 */ 1291 1292 1293 /// Generate the copy-helper function for a block closure object: 1294 /// static void block_copy_helper(block_t *dst, block_t *src); 1295 /// The runtime will have previously initialized 'dst' by doing a 1296 /// bit-copy of 'src'. 1297 /// 1298 /// Note that this copies an entire block closure object to the heap; 1299 /// it should not be confused with a 'byref copy helper', which moves 1300 /// the contents of an individual __block variable to the heap. 1301 llvm::Constant * 1302 CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) { 1303 ASTContext &C = getContext(); 1304 1305 FunctionArgList args; 1306 ImplicitParamDecl dstDecl(getContext(), nullptr, SourceLocation(), nullptr, 1307 C.VoidPtrTy); 1308 args.push_back(&dstDecl); 1309 ImplicitParamDecl srcDecl(getContext(), nullptr, SourceLocation(), nullptr, 1310 C.VoidPtrTy); 1311 args.push_back(&srcDecl); 1312 1313 const CGFunctionInfo &FI = CGM.getTypes().arrangeFreeFunctionDeclaration( 1314 C.VoidTy, args, FunctionType::ExtInfo(), /*variadic=*/false); 1315 1316 // FIXME: it would be nice if these were mergeable with things with 1317 // identical semantics. 1318 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI); 1319 1320 llvm::Function *Fn = 1321 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, 1322 "__copy_helper_block_", &CGM.getModule()); 1323 1324 IdentifierInfo *II 1325 = &CGM.getContext().Idents.get("__copy_helper_block_"); 1326 1327 FunctionDecl *FD = FunctionDecl::Create(C, 1328 C.getTranslationUnitDecl(), 1329 SourceLocation(), 1330 SourceLocation(), II, C.VoidTy, 1331 nullptr, SC_Static, 1332 false, 1333 false); 1334 auto NL = ApplyDebugLocation::CreateEmpty(*this); 1335 StartFunction(FD, C.VoidTy, Fn, FI, args); 1336 // Create a scope with an artificial location for the body of this function. 1337 auto AL = ApplyDebugLocation::CreateArtificial(*this); 1338 llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo(); 1339 1340 llvm::Value *src = GetAddrOfLocalVar(&srcDecl); 1341 src = Builder.CreateLoad(src); 1342 src = Builder.CreateBitCast(src, structPtrTy, "block.source"); 1343 1344 llvm::Value *dst = GetAddrOfLocalVar(&dstDecl); 1345 dst = Builder.CreateLoad(dst); 1346 dst = Builder.CreateBitCast(dst, structPtrTy, "block.dest"); 1347 1348 const BlockDecl *blockDecl = blockInfo.getBlockDecl(); 1349 1350 for (const auto &CI : blockDecl->captures()) { 1351 const VarDecl *variable = CI.getVariable(); 1352 QualType type = variable->getType(); 1353 1354 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 1355 if (capture.isConstant()) continue; 1356 1357 const Expr *copyExpr = CI.getCopyExpr(); 1358 BlockFieldFlags flags; 1359 1360 bool useARCWeakCopy = false; 1361 bool useARCStrongCopy = false; 1362 1363 if (copyExpr) { 1364 assert(!CI.isByRef()); 1365 // don't bother computing flags 1366 1367 } else if (CI.isByRef()) { 1368 flags = BLOCK_FIELD_IS_BYREF; 1369 if (type.isObjCGCWeak()) 1370 flags |= BLOCK_FIELD_IS_WEAK; 1371 1372 } else if (type->isObjCRetainableType()) { 1373 flags = BLOCK_FIELD_IS_OBJECT; 1374 bool isBlockPointer = type->isBlockPointerType(); 1375 if (isBlockPointer) 1376 flags = BLOCK_FIELD_IS_BLOCK; 1377 1378 // Special rules for ARC captures: 1379 if (getLangOpts().ObjCAutoRefCount) { 1380 Qualifiers qs = type.getQualifiers(); 1381 1382 // We need to register __weak direct captures with the runtime. 1383 if (qs.getObjCLifetime() == Qualifiers::OCL_Weak) { 1384 useARCWeakCopy = true; 1385 1386 // We need to retain the copied value for __strong direct captures. 1387 } else if (qs.getObjCLifetime() == Qualifiers::OCL_Strong) { 1388 // If it's a block pointer, we have to copy the block and 1389 // assign that to the destination pointer, so we might as 1390 // well use _Block_object_assign. Otherwise we can avoid that. 1391 if (!isBlockPointer) 1392 useARCStrongCopy = true; 1393 1394 // Otherwise the memcpy is fine. 1395 } else { 1396 continue; 1397 } 1398 1399 // Non-ARC captures of retainable pointers are strong and 1400 // therefore require a call to _Block_object_assign. 1401 } else { 1402 // fall through 1403 } 1404 } else { 1405 continue; 1406 } 1407 1408 unsigned index = capture.getIndex(); 1409 llvm::Value *srcField = 1410 Builder.CreateStructGEP(blockInfo.StructureType, src, index); 1411 llvm::Value *dstField = 1412 Builder.CreateStructGEP(blockInfo.StructureType, dst, index); 1413 1414 // If there's an explicit copy expression, we do that. 1415 if (copyExpr) { 1416 EmitSynthesizedCXXCopyCtor(dstField, srcField, copyExpr); 1417 } else if (useARCWeakCopy) { 1418 EmitARCCopyWeak(dstField, srcField); 1419 } else { 1420 llvm::Value *srcValue = Builder.CreateLoad(srcField, "blockcopy.src"); 1421 if (useARCStrongCopy) { 1422 // At -O0, store null into the destination field (so that the 1423 // storeStrong doesn't over-release) and then call storeStrong. 1424 // This is a workaround to not having an initStrong call. 1425 if (CGM.getCodeGenOpts().OptimizationLevel == 0) { 1426 auto *ty = cast<llvm::PointerType>(srcValue->getType()); 1427 llvm::Value *null = llvm::ConstantPointerNull::get(ty); 1428 Builder.CreateStore(null, dstField); 1429 EmitARCStoreStrongCall(dstField, srcValue, true); 1430 1431 // With optimization enabled, take advantage of the fact that 1432 // the blocks runtime guarantees a memcpy of the block data, and 1433 // just emit a retain of the src field. 1434 } else { 1435 EmitARCRetainNonBlock(srcValue); 1436 1437 // We don't need this anymore, so kill it. It's not quite 1438 // worth the annoyance to avoid creating it in the first place. 1439 cast<llvm::Instruction>(dstField)->eraseFromParent(); 1440 } 1441 } else { 1442 srcValue = Builder.CreateBitCast(srcValue, VoidPtrTy); 1443 llvm::Value *dstAddr = Builder.CreateBitCast(dstField, VoidPtrTy); 1444 llvm::Value *args[] = { 1445 dstAddr, srcValue, llvm::ConstantInt::get(Int32Ty, flags.getBitMask()) 1446 }; 1447 1448 bool copyCanThrow = false; 1449 if (CI.isByRef() && variable->getType()->getAsCXXRecordDecl()) { 1450 const Expr *copyExpr = 1451 CGM.getContext().getBlockVarCopyInits(variable); 1452 if (copyExpr) { 1453 copyCanThrow = true; // FIXME: reuse the noexcept logic 1454 } 1455 } 1456 1457 if (copyCanThrow) { 1458 EmitRuntimeCallOrInvoke(CGM.getBlockObjectAssign(), args); 1459 } else { 1460 EmitNounwindRuntimeCall(CGM.getBlockObjectAssign(), args); 1461 } 1462 } 1463 } 1464 } 1465 1466 FinishFunction(); 1467 1468 return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy); 1469 } 1470 1471 /// Generate the destroy-helper function for a block closure object: 1472 /// static void block_destroy_helper(block_t *theBlock); 1473 /// 1474 /// Note that this destroys a heap-allocated block closure object; 1475 /// it should not be confused with a 'byref destroy helper', which 1476 /// destroys the heap-allocated contents of an individual __block 1477 /// variable. 1478 llvm::Constant * 1479 CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) { 1480 ASTContext &C = getContext(); 1481 1482 FunctionArgList args; 1483 ImplicitParamDecl srcDecl(getContext(), nullptr, SourceLocation(), nullptr, 1484 C.VoidPtrTy); 1485 args.push_back(&srcDecl); 1486 1487 const CGFunctionInfo &FI = CGM.getTypes().arrangeFreeFunctionDeclaration( 1488 C.VoidTy, args, FunctionType::ExtInfo(), /*variadic=*/false); 1489 1490 // FIXME: We'd like to put these into a mergable by content, with 1491 // internal linkage. 1492 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI); 1493 1494 llvm::Function *Fn = 1495 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, 1496 "__destroy_helper_block_", &CGM.getModule()); 1497 1498 IdentifierInfo *II 1499 = &CGM.getContext().Idents.get("__destroy_helper_block_"); 1500 1501 FunctionDecl *FD = FunctionDecl::Create(C, C.getTranslationUnitDecl(), 1502 SourceLocation(), 1503 SourceLocation(), II, C.VoidTy, 1504 nullptr, SC_Static, 1505 false, false); 1506 // Create a scope with an artificial location for the body of this function. 1507 auto NL = ApplyDebugLocation::CreateEmpty(*this); 1508 StartFunction(FD, C.VoidTy, Fn, FI, args); 1509 auto AL = ApplyDebugLocation::CreateArtificial(*this); 1510 1511 llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo(); 1512 1513 llvm::Value *src = GetAddrOfLocalVar(&srcDecl); 1514 src = Builder.CreateLoad(src); 1515 src = Builder.CreateBitCast(src, structPtrTy, "block"); 1516 1517 const BlockDecl *blockDecl = blockInfo.getBlockDecl(); 1518 1519 CodeGenFunction::RunCleanupsScope cleanups(*this); 1520 1521 for (const auto &CI : blockDecl->captures()) { 1522 const VarDecl *variable = CI.getVariable(); 1523 QualType type = variable->getType(); 1524 1525 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 1526 if (capture.isConstant()) continue; 1527 1528 BlockFieldFlags flags; 1529 const CXXDestructorDecl *dtor = nullptr; 1530 1531 bool useARCWeakDestroy = false; 1532 bool useARCStrongDestroy = false; 1533 1534 if (CI.isByRef()) { 1535 flags = BLOCK_FIELD_IS_BYREF; 1536 if (type.isObjCGCWeak()) 1537 flags |= BLOCK_FIELD_IS_WEAK; 1538 } else if (const CXXRecordDecl *record = type->getAsCXXRecordDecl()) { 1539 if (record->hasTrivialDestructor()) 1540 continue; 1541 dtor = record->getDestructor(); 1542 } else if (type->isObjCRetainableType()) { 1543 flags = BLOCK_FIELD_IS_OBJECT; 1544 if (type->isBlockPointerType()) 1545 flags = BLOCK_FIELD_IS_BLOCK; 1546 1547 // Special rules for ARC captures. 1548 if (getLangOpts().ObjCAutoRefCount) { 1549 Qualifiers qs = type.getQualifiers(); 1550 1551 // Don't generate special dispose logic for a captured object 1552 // unless it's __strong or __weak. 1553 if (!qs.hasStrongOrWeakObjCLifetime()) 1554 continue; 1555 1556 // Support __weak direct captures. 1557 if (qs.getObjCLifetime() == Qualifiers::OCL_Weak) 1558 useARCWeakDestroy = true; 1559 1560 // Tools really want us to use objc_storeStrong here. 1561 else 1562 useARCStrongDestroy = true; 1563 } 1564 } else { 1565 continue; 1566 } 1567 1568 unsigned index = capture.getIndex(); 1569 llvm::Value *srcField = 1570 Builder.CreateStructGEP(blockInfo.StructureType, src, index); 1571 1572 // If there's an explicit copy expression, we do that. 1573 if (dtor) { 1574 PushDestructorCleanup(dtor, srcField); 1575 1576 // If this is a __weak capture, emit the release directly. 1577 } else if (useARCWeakDestroy) { 1578 EmitARCDestroyWeak(srcField); 1579 1580 // Destroy strong objects with a call if requested. 1581 } else if (useARCStrongDestroy) { 1582 EmitARCDestroyStrong(srcField, ARCImpreciseLifetime); 1583 1584 // Otherwise we call _Block_object_dispose. It wouldn't be too 1585 // hard to just emit this as a cleanup if we wanted to make sure 1586 // that things were done in reverse. 1587 } else { 1588 llvm::Value *value = Builder.CreateLoad(srcField); 1589 value = Builder.CreateBitCast(value, VoidPtrTy); 1590 BuildBlockRelease(value, flags); 1591 } 1592 } 1593 1594 cleanups.ForceCleanup(); 1595 1596 FinishFunction(); 1597 1598 return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy); 1599 } 1600 1601 namespace { 1602 1603 /// Emits the copy/dispose helper functions for a __block object of id type. 1604 class ObjectByrefHelpers : public CodeGenModule::ByrefHelpers { 1605 BlockFieldFlags Flags; 1606 1607 public: 1608 ObjectByrefHelpers(CharUnits alignment, BlockFieldFlags flags) 1609 : ByrefHelpers(alignment), Flags(flags) {} 1610 1611 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1612 llvm::Value *srcField) override { 1613 destField = CGF.Builder.CreateBitCast(destField, CGF.VoidPtrTy); 1614 1615 srcField = CGF.Builder.CreateBitCast(srcField, CGF.VoidPtrPtrTy); 1616 llvm::Value *srcValue = CGF.Builder.CreateLoad(srcField); 1617 1618 unsigned flags = (Flags | BLOCK_BYREF_CALLER).getBitMask(); 1619 1620 llvm::Value *flagsVal = llvm::ConstantInt::get(CGF.Int32Ty, flags); 1621 llvm::Value *fn = CGF.CGM.getBlockObjectAssign(); 1622 1623 llvm::Value *args[] = { destField, srcValue, flagsVal }; 1624 CGF.EmitNounwindRuntimeCall(fn, args); 1625 } 1626 1627 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) override { 1628 field = CGF.Builder.CreateBitCast(field, CGF.Int8PtrTy->getPointerTo(0)); 1629 llvm::Value *value = CGF.Builder.CreateLoad(field); 1630 1631 CGF.BuildBlockRelease(value, Flags | BLOCK_BYREF_CALLER); 1632 } 1633 1634 void profileImpl(llvm::FoldingSetNodeID &id) const override { 1635 id.AddInteger(Flags.getBitMask()); 1636 } 1637 }; 1638 1639 /// Emits the copy/dispose helpers for an ARC __block __weak variable. 1640 class ARCWeakByrefHelpers : public CodeGenModule::ByrefHelpers { 1641 public: 1642 ARCWeakByrefHelpers(CharUnits alignment) : ByrefHelpers(alignment) {} 1643 1644 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1645 llvm::Value *srcField) override { 1646 CGF.EmitARCMoveWeak(destField, srcField); 1647 } 1648 1649 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) override { 1650 CGF.EmitARCDestroyWeak(field); 1651 } 1652 1653 void profileImpl(llvm::FoldingSetNodeID &id) const override { 1654 // 0 is distinguishable from all pointers and byref flags 1655 id.AddInteger(0); 1656 } 1657 }; 1658 1659 /// Emits the copy/dispose helpers for an ARC __block __strong variable 1660 /// that's not of block-pointer type. 1661 class ARCStrongByrefHelpers : public CodeGenModule::ByrefHelpers { 1662 public: 1663 ARCStrongByrefHelpers(CharUnits alignment) : ByrefHelpers(alignment) {} 1664 1665 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1666 llvm::Value *srcField) override { 1667 // Do a "move" by copying the value and then zeroing out the old 1668 // variable. 1669 1670 llvm::LoadInst *value = CGF.Builder.CreateLoad(srcField); 1671 value->setAlignment(Alignment.getQuantity()); 1672 1673 llvm::Value *null = 1674 llvm::ConstantPointerNull::get(cast<llvm::PointerType>(value->getType())); 1675 1676 if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0) { 1677 llvm::StoreInst *store = CGF.Builder.CreateStore(null, destField); 1678 store->setAlignment(Alignment.getQuantity()); 1679 CGF.EmitARCStoreStrongCall(destField, value, /*ignored*/ true); 1680 CGF.EmitARCStoreStrongCall(srcField, null, /*ignored*/ true); 1681 return; 1682 } 1683 llvm::StoreInst *store = CGF.Builder.CreateStore(value, destField); 1684 store->setAlignment(Alignment.getQuantity()); 1685 1686 store = CGF.Builder.CreateStore(null, srcField); 1687 store->setAlignment(Alignment.getQuantity()); 1688 } 1689 1690 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) override { 1691 CGF.EmitARCDestroyStrong(field, ARCImpreciseLifetime); 1692 } 1693 1694 void profileImpl(llvm::FoldingSetNodeID &id) const override { 1695 // 1 is distinguishable from all pointers and byref flags 1696 id.AddInteger(1); 1697 } 1698 }; 1699 1700 /// Emits the copy/dispose helpers for an ARC __block __strong 1701 /// variable that's of block-pointer type. 1702 class ARCStrongBlockByrefHelpers : public CodeGenModule::ByrefHelpers { 1703 public: 1704 ARCStrongBlockByrefHelpers(CharUnits alignment) : ByrefHelpers(alignment) {} 1705 1706 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1707 llvm::Value *srcField) override { 1708 // Do the copy with objc_retainBlock; that's all that 1709 // _Block_object_assign would do anyway, and we'd have to pass the 1710 // right arguments to make sure it doesn't get no-op'ed. 1711 llvm::LoadInst *oldValue = CGF.Builder.CreateLoad(srcField); 1712 oldValue->setAlignment(Alignment.getQuantity()); 1713 1714 llvm::Value *copy = CGF.EmitARCRetainBlock(oldValue, /*mandatory*/ true); 1715 1716 llvm::StoreInst *store = CGF.Builder.CreateStore(copy, destField); 1717 store->setAlignment(Alignment.getQuantity()); 1718 } 1719 1720 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) override { 1721 CGF.EmitARCDestroyStrong(field, ARCImpreciseLifetime); 1722 } 1723 1724 void profileImpl(llvm::FoldingSetNodeID &id) const override { 1725 // 2 is distinguishable from all pointers and byref flags 1726 id.AddInteger(2); 1727 } 1728 }; 1729 1730 /// Emits the copy/dispose helpers for a __block variable with a 1731 /// nontrivial copy constructor or destructor. 1732 class CXXByrefHelpers : public CodeGenModule::ByrefHelpers { 1733 QualType VarType; 1734 const Expr *CopyExpr; 1735 1736 public: 1737 CXXByrefHelpers(CharUnits alignment, QualType type, 1738 const Expr *copyExpr) 1739 : ByrefHelpers(alignment), VarType(type), CopyExpr(copyExpr) {} 1740 1741 bool needsCopy() const override { return CopyExpr != nullptr; } 1742 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1743 llvm::Value *srcField) override { 1744 if (!CopyExpr) return; 1745 CGF.EmitSynthesizedCXXCopyCtor(destField, srcField, CopyExpr); 1746 } 1747 1748 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) override { 1749 EHScopeStack::stable_iterator cleanupDepth = CGF.EHStack.stable_begin(); 1750 CGF.PushDestructorCleanup(VarType, field); 1751 CGF.PopCleanupBlocks(cleanupDepth); 1752 } 1753 1754 void profileImpl(llvm::FoldingSetNodeID &id) const override { 1755 id.AddPointer(VarType.getCanonicalType().getAsOpaquePtr()); 1756 } 1757 }; 1758 } // end anonymous namespace 1759 1760 static llvm::Constant * 1761 generateByrefCopyHelper(CodeGenFunction &CGF, 1762 llvm::StructType &byrefType, 1763 unsigned valueFieldIndex, 1764 CodeGenModule::ByrefHelpers &byrefInfo) { 1765 ASTContext &Context = CGF.getContext(); 1766 1767 QualType R = Context.VoidTy; 1768 1769 FunctionArgList args; 1770 ImplicitParamDecl dst(CGF.getContext(), nullptr, SourceLocation(), nullptr, 1771 Context.VoidPtrTy); 1772 args.push_back(&dst); 1773 1774 ImplicitParamDecl src(CGF.getContext(), nullptr, SourceLocation(), nullptr, 1775 Context.VoidPtrTy); 1776 args.push_back(&src); 1777 1778 const CGFunctionInfo &FI = CGF.CGM.getTypes().arrangeFreeFunctionDeclaration( 1779 R, args, FunctionType::ExtInfo(), /*variadic=*/false); 1780 1781 CodeGenTypes &Types = CGF.CGM.getTypes(); 1782 llvm::FunctionType *LTy = Types.GetFunctionType(FI); 1783 1784 // FIXME: We'd like to put these into a mergable by content, with 1785 // internal linkage. 1786 llvm::Function *Fn = 1787 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, 1788 "__Block_byref_object_copy_", &CGF.CGM.getModule()); 1789 1790 IdentifierInfo *II 1791 = &Context.Idents.get("__Block_byref_object_copy_"); 1792 1793 FunctionDecl *FD = FunctionDecl::Create(Context, 1794 Context.getTranslationUnitDecl(), 1795 SourceLocation(), 1796 SourceLocation(), II, R, nullptr, 1797 SC_Static, 1798 false, false); 1799 1800 CGF.StartFunction(FD, R, Fn, FI, args); 1801 1802 if (byrefInfo.needsCopy()) { 1803 llvm::Type *byrefPtrType = byrefType.getPointerTo(0); 1804 1805 // dst->x 1806 llvm::Value *destField = CGF.GetAddrOfLocalVar(&dst); 1807 destField = CGF.Builder.CreateLoad(destField); 1808 destField = CGF.Builder.CreateBitCast(destField, byrefPtrType); 1809 destField = CGF.Builder.CreateStructGEP(&byrefType, destField, 1810 valueFieldIndex, "x"); 1811 1812 // src->x 1813 llvm::Value *srcField = CGF.GetAddrOfLocalVar(&src); 1814 srcField = CGF.Builder.CreateLoad(srcField); 1815 srcField = CGF.Builder.CreateBitCast(srcField, byrefPtrType); 1816 srcField = 1817 CGF.Builder.CreateStructGEP(&byrefType, srcField, valueFieldIndex, "x"); 1818 1819 byrefInfo.emitCopy(CGF, destField, srcField); 1820 } 1821 1822 CGF.FinishFunction(); 1823 1824 return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy); 1825 } 1826 1827 /// Build the copy helper for a __block variable. 1828 static llvm::Constant *buildByrefCopyHelper(CodeGenModule &CGM, 1829 llvm::StructType &byrefType, 1830 unsigned byrefValueIndex, 1831 CodeGenModule::ByrefHelpers &info) { 1832 CodeGenFunction CGF(CGM); 1833 return generateByrefCopyHelper(CGF, byrefType, byrefValueIndex, info); 1834 } 1835 1836 /// Generate code for a __block variable's dispose helper. 1837 static llvm::Constant * 1838 generateByrefDisposeHelper(CodeGenFunction &CGF, 1839 llvm::StructType &byrefType, 1840 unsigned byrefValueIndex, 1841 CodeGenModule::ByrefHelpers &byrefInfo) { 1842 ASTContext &Context = CGF.getContext(); 1843 QualType R = Context.VoidTy; 1844 1845 FunctionArgList args; 1846 ImplicitParamDecl src(CGF.getContext(), nullptr, SourceLocation(), nullptr, 1847 Context.VoidPtrTy); 1848 args.push_back(&src); 1849 1850 const CGFunctionInfo &FI = CGF.CGM.getTypes().arrangeFreeFunctionDeclaration( 1851 R, args, FunctionType::ExtInfo(), /*variadic=*/false); 1852 1853 CodeGenTypes &Types = CGF.CGM.getTypes(); 1854 llvm::FunctionType *LTy = Types.GetFunctionType(FI); 1855 1856 // FIXME: We'd like to put these into a mergable by content, with 1857 // internal linkage. 1858 llvm::Function *Fn = 1859 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, 1860 "__Block_byref_object_dispose_", 1861 &CGF.CGM.getModule()); 1862 1863 IdentifierInfo *II 1864 = &Context.Idents.get("__Block_byref_object_dispose_"); 1865 1866 FunctionDecl *FD = FunctionDecl::Create(Context, 1867 Context.getTranslationUnitDecl(), 1868 SourceLocation(), 1869 SourceLocation(), II, R, nullptr, 1870 SC_Static, 1871 false, false); 1872 CGF.StartFunction(FD, R, Fn, FI, args); 1873 1874 if (byrefInfo.needsDispose()) { 1875 llvm::Value *V = CGF.GetAddrOfLocalVar(&src); 1876 V = CGF.Builder.CreateLoad(V); 1877 V = CGF.Builder.CreateBitCast(V, byrefType.getPointerTo(0)); 1878 V = CGF.Builder.CreateStructGEP(&byrefType, V, byrefValueIndex, "x"); 1879 1880 byrefInfo.emitDispose(CGF, V); 1881 } 1882 1883 CGF.FinishFunction(); 1884 1885 return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy); 1886 } 1887 1888 /// Build the dispose helper for a __block variable. 1889 static llvm::Constant *buildByrefDisposeHelper(CodeGenModule &CGM, 1890 llvm::StructType &byrefType, 1891 unsigned byrefValueIndex, 1892 CodeGenModule::ByrefHelpers &info) { 1893 CodeGenFunction CGF(CGM); 1894 return generateByrefDisposeHelper(CGF, byrefType, byrefValueIndex, info); 1895 } 1896 1897 /// Lazily build the copy and dispose helpers for a __block variable 1898 /// with the given information. 1899 template <class T> static T *buildByrefHelpers(CodeGenModule &CGM, 1900 llvm::StructType &byrefTy, 1901 unsigned byrefValueIndex, 1902 T &byrefInfo) { 1903 // Increase the field's alignment to be at least pointer alignment, 1904 // since the layout of the byref struct will guarantee at least that. 1905 byrefInfo.Alignment = std::max(byrefInfo.Alignment, 1906 CharUnits::fromQuantity(CGM.PointerAlignInBytes)); 1907 1908 llvm::FoldingSetNodeID id; 1909 byrefInfo.Profile(id); 1910 1911 void *insertPos; 1912 CodeGenModule::ByrefHelpers *node 1913 = CGM.ByrefHelpersCache.FindNodeOrInsertPos(id, insertPos); 1914 if (node) return static_cast<T*>(node); 1915 1916 byrefInfo.CopyHelper = 1917 buildByrefCopyHelper(CGM, byrefTy, byrefValueIndex, byrefInfo); 1918 byrefInfo.DisposeHelper = 1919 buildByrefDisposeHelper(CGM, byrefTy, byrefValueIndex,byrefInfo); 1920 1921 T *copy = new (CGM.getContext()) T(byrefInfo); 1922 CGM.ByrefHelpersCache.InsertNode(copy, insertPos); 1923 return copy; 1924 } 1925 1926 /// Build the copy and dispose helpers for the given __block variable 1927 /// emission. Places the helpers in the global cache. Returns null 1928 /// if no helpers are required. 1929 CodeGenModule::ByrefHelpers * 1930 CodeGenFunction::buildByrefHelpers(llvm::StructType &byrefType, 1931 const AutoVarEmission &emission) { 1932 const VarDecl &var = *emission.Variable; 1933 QualType type = var.getType(); 1934 1935 unsigned byrefValueIndex = getByRefValueLLVMField(&var).second; 1936 1937 if (const CXXRecordDecl *record = type->getAsCXXRecordDecl()) { 1938 const Expr *copyExpr = CGM.getContext().getBlockVarCopyInits(&var); 1939 if (!copyExpr && record->hasTrivialDestructor()) return nullptr; 1940 1941 CXXByrefHelpers byrefInfo(emission.Alignment, type, copyExpr); 1942 return ::buildByrefHelpers(CGM, byrefType, byrefValueIndex, byrefInfo); 1943 } 1944 1945 // Otherwise, if we don't have a retainable type, there's nothing to do. 1946 // that the runtime does extra copies. 1947 if (!type->isObjCRetainableType()) return nullptr; 1948 1949 Qualifiers qs = type.getQualifiers(); 1950 1951 // If we have lifetime, that dominates. 1952 if (Qualifiers::ObjCLifetime lifetime = qs.getObjCLifetime()) { 1953 assert(getLangOpts().ObjCAutoRefCount); 1954 1955 switch (lifetime) { 1956 case Qualifiers::OCL_None: llvm_unreachable("impossible"); 1957 1958 // These are just bits as far as the runtime is concerned. 1959 case Qualifiers::OCL_ExplicitNone: 1960 case Qualifiers::OCL_Autoreleasing: 1961 return nullptr; 1962 1963 // Tell the runtime that this is ARC __weak, called by the 1964 // byref routines. 1965 case Qualifiers::OCL_Weak: { 1966 ARCWeakByrefHelpers byrefInfo(emission.Alignment); 1967 return ::buildByrefHelpers(CGM, byrefType, byrefValueIndex, byrefInfo); 1968 } 1969 1970 // ARC __strong __block variables need to be retained. 1971 case Qualifiers::OCL_Strong: 1972 // Block pointers need to be copied, and there's no direct 1973 // transfer possible. 1974 if (type->isBlockPointerType()) { 1975 ARCStrongBlockByrefHelpers byrefInfo(emission.Alignment); 1976 return ::buildByrefHelpers(CGM, byrefType, byrefValueIndex, byrefInfo); 1977 1978 // Otherwise, we transfer ownership of the retain from the stack 1979 // to the heap. 1980 } else { 1981 ARCStrongByrefHelpers byrefInfo(emission.Alignment); 1982 return ::buildByrefHelpers(CGM, byrefType, byrefValueIndex, byrefInfo); 1983 } 1984 } 1985 llvm_unreachable("fell out of lifetime switch!"); 1986 } 1987 1988 BlockFieldFlags flags; 1989 if (type->isBlockPointerType()) { 1990 flags |= BLOCK_FIELD_IS_BLOCK; 1991 } else if (CGM.getContext().isObjCNSObjectType(type) || 1992 type->isObjCObjectPointerType()) { 1993 flags |= BLOCK_FIELD_IS_OBJECT; 1994 } else { 1995 return nullptr; 1996 } 1997 1998 if (type.isObjCGCWeak()) 1999 flags |= BLOCK_FIELD_IS_WEAK; 2000 2001 ObjectByrefHelpers byrefInfo(emission.Alignment, flags); 2002 return ::buildByrefHelpers(CGM, byrefType, byrefValueIndex, byrefInfo); 2003 } 2004 2005 std::pair<llvm::Type *, unsigned> 2006 CodeGenFunction::getByRefValueLLVMField(const ValueDecl *VD) const { 2007 assert(ByRefValueInfo.count(VD) && "Did not find value!"); 2008 2009 return ByRefValueInfo.find(VD)->second; 2010 } 2011 2012 llvm::Value *CodeGenFunction::BuildBlockByrefAddress(llvm::Value *BaseAddr, 2013 const VarDecl *V) { 2014 auto P = getByRefValueLLVMField(V); 2015 llvm::Value *Loc = 2016 Builder.CreateStructGEP(P.first, BaseAddr, 1, "forwarding"); 2017 Loc = Builder.CreateLoad(Loc); 2018 Loc = Builder.CreateStructGEP(P.first, Loc, P.second, V->getNameAsString()); 2019 return Loc; 2020 } 2021 2022 /// BuildByRefType - This routine changes a __block variable declared as T x 2023 /// into: 2024 /// 2025 /// struct { 2026 /// void *__isa; 2027 /// void *__forwarding; 2028 /// int32_t __flags; 2029 /// int32_t __size; 2030 /// void *__copy_helper; // only if needed 2031 /// void *__destroy_helper; // only if needed 2032 /// void *__byref_variable_layout;// only if needed 2033 /// char padding[X]; // only if needed 2034 /// T x; 2035 /// } x 2036 /// 2037 llvm::Type *CodeGenFunction::BuildByRefType(const VarDecl *D) { 2038 std::pair<llvm::Type *, unsigned> &Info = ByRefValueInfo[D]; 2039 if (Info.first) 2040 return Info.first; 2041 2042 QualType Ty = D->getType(); 2043 2044 SmallVector<llvm::Type *, 8> types; 2045 2046 llvm::StructType *ByRefType = 2047 llvm::StructType::create(getLLVMContext(), 2048 "struct.__block_byref_" + D->getNameAsString()); 2049 2050 // void *__isa; 2051 types.push_back(Int8PtrTy); 2052 2053 // void *__forwarding; 2054 types.push_back(llvm::PointerType::getUnqual(ByRefType)); 2055 2056 // int32_t __flags; 2057 types.push_back(Int32Ty); 2058 2059 // int32_t __size; 2060 types.push_back(Int32Ty); 2061 // Note that this must match *exactly* the logic in buildByrefHelpers. 2062 bool HasCopyAndDispose = getContext().BlockRequiresCopying(Ty, D); 2063 if (HasCopyAndDispose) { 2064 /// void *__copy_helper; 2065 types.push_back(Int8PtrTy); 2066 2067 /// void *__destroy_helper; 2068 types.push_back(Int8PtrTy); 2069 } 2070 bool HasByrefExtendedLayout = false; 2071 Qualifiers::ObjCLifetime Lifetime; 2072 if (getContext().getByrefLifetime(Ty, Lifetime, HasByrefExtendedLayout) && 2073 HasByrefExtendedLayout) 2074 /// void *__byref_variable_layout; 2075 types.push_back(Int8PtrTy); 2076 2077 bool Packed = false; 2078 CharUnits Align = getContext().getDeclAlign(D); 2079 if (Align > 2080 getContext().toCharUnitsFromBits(getTarget().getPointerAlign(0))) { 2081 // We have to insert padding. 2082 2083 // The struct above has 2 32-bit integers. 2084 unsigned CurrentOffsetInBytes = 4 * 2; 2085 2086 // And either 2, 3, 4 or 5 pointers. 2087 unsigned noPointers = 2; 2088 if (HasCopyAndDispose) 2089 noPointers += 2; 2090 if (HasByrefExtendedLayout) 2091 noPointers += 1; 2092 2093 CurrentOffsetInBytes += noPointers * CGM.getDataLayout().getTypeAllocSize(Int8PtrTy); 2094 2095 // Align the offset. 2096 unsigned AlignedOffsetInBytes = 2097 llvm::RoundUpToAlignment(CurrentOffsetInBytes, Align.getQuantity()); 2098 2099 unsigned NumPaddingBytes = AlignedOffsetInBytes - CurrentOffsetInBytes; 2100 if (NumPaddingBytes > 0) { 2101 llvm::Type *Ty = Int8Ty; 2102 // FIXME: We need a sema error for alignment larger than the minimum of 2103 // the maximal stack alignment and the alignment of malloc on the system. 2104 if (NumPaddingBytes > 1) 2105 Ty = llvm::ArrayType::get(Ty, NumPaddingBytes); 2106 2107 types.push_back(Ty); 2108 2109 // We want a packed struct. 2110 Packed = true; 2111 } 2112 } 2113 2114 // T x; 2115 types.push_back(ConvertTypeForMem(Ty)); 2116 2117 ByRefType->setBody(types, Packed); 2118 2119 Info.first = ByRefType; 2120 2121 Info.second = types.size() - 1; 2122 2123 return Info.first; 2124 } 2125 2126 /// Initialize the structural components of a __block variable, i.e. 2127 /// everything but the actual object. 2128 void CodeGenFunction::emitByrefStructureInit(const AutoVarEmission &emission) { 2129 // Find the address of the local. 2130 llvm::Value *addr = emission.Address; 2131 2132 // That's an alloca of the byref structure type. 2133 llvm::StructType *byrefType = cast<llvm::StructType>( 2134 cast<llvm::PointerType>(addr->getType())->getElementType()); 2135 2136 // Build the byref helpers if necessary. This is null if we don't need any. 2137 CodeGenModule::ByrefHelpers *helpers = 2138 buildByrefHelpers(*byrefType, emission); 2139 2140 const VarDecl &D = *emission.Variable; 2141 QualType type = D.getType(); 2142 2143 bool HasByrefExtendedLayout; 2144 Qualifiers::ObjCLifetime ByrefLifetime; 2145 bool ByRefHasLifetime = 2146 getContext().getByrefLifetime(type, ByrefLifetime, HasByrefExtendedLayout); 2147 2148 llvm::Value *V; 2149 2150 // Initialize the 'isa', which is just 0 or 1. 2151 int isa = 0; 2152 if (type.isObjCGCWeak()) 2153 isa = 1; 2154 V = Builder.CreateIntToPtr(Builder.getInt32(isa), Int8PtrTy, "isa"); 2155 Builder.CreateStore(V, 2156 Builder.CreateStructGEP(nullptr, addr, 0, "byref.isa")); 2157 2158 // Store the address of the variable into its own forwarding pointer. 2159 Builder.CreateStore( 2160 addr, Builder.CreateStructGEP(nullptr, addr, 1, "byref.forwarding")); 2161 2162 // Blocks ABI: 2163 // c) the flags field is set to either 0 if no helper functions are 2164 // needed or BLOCK_BYREF_HAS_COPY_DISPOSE if they are, 2165 BlockFlags flags; 2166 if (helpers) flags |= BLOCK_BYREF_HAS_COPY_DISPOSE; 2167 if (ByRefHasLifetime) { 2168 if (HasByrefExtendedLayout) flags |= BLOCK_BYREF_LAYOUT_EXTENDED; 2169 else switch (ByrefLifetime) { 2170 case Qualifiers::OCL_Strong: 2171 flags |= BLOCK_BYREF_LAYOUT_STRONG; 2172 break; 2173 case Qualifiers::OCL_Weak: 2174 flags |= BLOCK_BYREF_LAYOUT_WEAK; 2175 break; 2176 case Qualifiers::OCL_ExplicitNone: 2177 flags |= BLOCK_BYREF_LAYOUT_UNRETAINED; 2178 break; 2179 case Qualifiers::OCL_None: 2180 if (!type->isObjCObjectPointerType() && !type->isBlockPointerType()) 2181 flags |= BLOCK_BYREF_LAYOUT_NON_OBJECT; 2182 break; 2183 default: 2184 break; 2185 } 2186 if (CGM.getLangOpts().ObjCGCBitmapPrint) { 2187 printf("\n Inline flag for BYREF variable layout (%d):", flags.getBitMask()); 2188 if (flags & BLOCK_BYREF_HAS_COPY_DISPOSE) 2189 printf(" BLOCK_BYREF_HAS_COPY_DISPOSE"); 2190 if (flags & BLOCK_BYREF_LAYOUT_MASK) { 2191 BlockFlags ThisFlag(flags.getBitMask() & BLOCK_BYREF_LAYOUT_MASK); 2192 if (ThisFlag == BLOCK_BYREF_LAYOUT_EXTENDED) 2193 printf(" BLOCK_BYREF_LAYOUT_EXTENDED"); 2194 if (ThisFlag == BLOCK_BYREF_LAYOUT_STRONG) 2195 printf(" BLOCK_BYREF_LAYOUT_STRONG"); 2196 if (ThisFlag == BLOCK_BYREF_LAYOUT_WEAK) 2197 printf(" BLOCK_BYREF_LAYOUT_WEAK"); 2198 if (ThisFlag == BLOCK_BYREF_LAYOUT_UNRETAINED) 2199 printf(" BLOCK_BYREF_LAYOUT_UNRETAINED"); 2200 if (ThisFlag == BLOCK_BYREF_LAYOUT_NON_OBJECT) 2201 printf(" BLOCK_BYREF_LAYOUT_NON_OBJECT"); 2202 } 2203 printf("\n"); 2204 } 2205 } 2206 2207 Builder.CreateStore(llvm::ConstantInt::get(IntTy, flags.getBitMask()), 2208 Builder.CreateStructGEP(nullptr, addr, 2, "byref.flags")); 2209 2210 CharUnits byrefSize = CGM.GetTargetTypeStoreSize(byrefType); 2211 V = llvm::ConstantInt::get(IntTy, byrefSize.getQuantity()); 2212 Builder.CreateStore(V, 2213 Builder.CreateStructGEP(nullptr, addr, 3, "byref.size")); 2214 2215 if (helpers) { 2216 llvm::Value *copy_helper = Builder.CreateStructGEP(nullptr, addr, 4); 2217 Builder.CreateStore(helpers->CopyHelper, copy_helper); 2218 2219 llvm::Value *destroy_helper = Builder.CreateStructGEP(nullptr, addr, 5); 2220 Builder.CreateStore(helpers->DisposeHelper, destroy_helper); 2221 } 2222 if (ByRefHasLifetime && HasByrefExtendedLayout) { 2223 llvm::Constant* ByrefLayoutInfo = CGM.getObjCRuntime().BuildByrefLayout(CGM, type); 2224 llvm::Value *ByrefInfoAddr = 2225 Builder.CreateStructGEP(nullptr, addr, helpers ? 6 : 4, "byref.layout"); 2226 // cast destination to pointer to source type. 2227 llvm::Type *DesTy = ByrefLayoutInfo->getType(); 2228 DesTy = DesTy->getPointerTo(); 2229 llvm::Value *BC = Builder.CreatePointerCast(ByrefInfoAddr, DesTy); 2230 Builder.CreateStore(ByrefLayoutInfo, BC); 2231 } 2232 } 2233 2234 void CodeGenFunction::BuildBlockRelease(llvm::Value *V, BlockFieldFlags flags) { 2235 llvm::Value *F = CGM.getBlockObjectDispose(); 2236 llvm::Value *args[] = { 2237 Builder.CreateBitCast(V, Int8PtrTy), 2238 llvm::ConstantInt::get(Int32Ty, flags.getBitMask()) 2239 }; 2240 EmitNounwindRuntimeCall(F, args); // FIXME: throwing destructors? 2241 } 2242 2243 namespace { 2244 struct CallBlockRelease : EHScopeStack::Cleanup { 2245 llvm::Value *Addr; 2246 CallBlockRelease(llvm::Value *Addr) : Addr(Addr) {} 2247 2248 void Emit(CodeGenFunction &CGF, Flags flags) override { 2249 // Should we be passing FIELD_IS_WEAK here? 2250 CGF.BuildBlockRelease(Addr, BLOCK_FIELD_IS_BYREF); 2251 } 2252 }; 2253 } 2254 2255 /// Enter a cleanup to destroy a __block variable. Note that this 2256 /// cleanup should be a no-op if the variable hasn't left the stack 2257 /// yet; if a cleanup is required for the variable itself, that needs 2258 /// to be done externally. 2259 void CodeGenFunction::enterByrefCleanup(const AutoVarEmission &emission) { 2260 // We don't enter this cleanup if we're in pure-GC mode. 2261 if (CGM.getLangOpts().getGC() == LangOptions::GCOnly) 2262 return; 2263 2264 EHStack.pushCleanup<CallBlockRelease>(NormalAndEHCleanup, emission.Address); 2265 } 2266 2267 /// Adjust the declaration of something from the blocks API. 2268 static void configureBlocksRuntimeObject(CodeGenModule &CGM, 2269 llvm::Constant *C) { 2270 if (!CGM.getLangOpts().BlocksRuntimeOptional) return; 2271 2272 auto *GV = cast<llvm::GlobalValue>(C->stripPointerCasts()); 2273 if (GV->isDeclaration() && GV->hasExternalLinkage()) 2274 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage); 2275 } 2276 2277 llvm::Constant *CodeGenModule::getBlockObjectDispose() { 2278 if (BlockObjectDispose) 2279 return BlockObjectDispose; 2280 2281 llvm::Type *args[] = { Int8PtrTy, Int32Ty }; 2282 llvm::FunctionType *fty 2283 = llvm::FunctionType::get(VoidTy, args, false); 2284 BlockObjectDispose = CreateRuntimeFunction(fty, "_Block_object_dispose"); 2285 configureBlocksRuntimeObject(*this, BlockObjectDispose); 2286 return BlockObjectDispose; 2287 } 2288 2289 llvm::Constant *CodeGenModule::getBlockObjectAssign() { 2290 if (BlockObjectAssign) 2291 return BlockObjectAssign; 2292 2293 llvm::Type *args[] = { Int8PtrTy, Int8PtrTy, Int32Ty }; 2294 llvm::FunctionType *fty 2295 = llvm::FunctionType::get(VoidTy, args, false); 2296 BlockObjectAssign = CreateRuntimeFunction(fty, "_Block_object_assign"); 2297 configureBlocksRuntimeObject(*this, BlockObjectAssign); 2298 return BlockObjectAssign; 2299 } 2300 2301 llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() { 2302 if (NSConcreteGlobalBlock) 2303 return NSConcreteGlobalBlock; 2304 2305 NSConcreteGlobalBlock = GetOrCreateLLVMGlobal("_NSConcreteGlobalBlock", 2306 Int8PtrTy->getPointerTo(), 2307 nullptr); 2308 configureBlocksRuntimeObject(*this, NSConcreteGlobalBlock); 2309 return NSConcreteGlobalBlock; 2310 } 2311 2312 llvm::Constant *CodeGenModule::getNSConcreteStackBlock() { 2313 if (NSConcreteStackBlock) 2314 return NSConcreteStackBlock; 2315 2316 NSConcreteStackBlock = GetOrCreateLLVMGlobal("_NSConcreteStackBlock", 2317 Int8PtrTy->getPointerTo(), 2318 nullptr); 2319 configureBlocksRuntimeObject(*this, NSConcreteStackBlock); 2320 return NSConcreteStackBlock; 2321 } 2322