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 "CGDebugInfo.h" 15 #include "CodeGenFunction.h" 16 #include "CGObjCRuntime.h" 17 #include "CodeGenModule.h" 18 #include "CGBlocks.h" 19 #include "clang/AST/DeclObjC.h" 20 #include "llvm/Module.h" 21 #include "llvm/ADT/SmallSet.h" 22 #include "llvm/Target/TargetData.h" 23 #include <algorithm> 24 25 using namespace clang; 26 using namespace CodeGen; 27 28 CGBlockInfo::CGBlockInfo(const BlockExpr *blockExpr, const char *N) 29 : Name(N), CXXThisIndex(0), CanBeGlobal(false), NeedsCopyDispose(false), 30 HasCXXObject(false), UsesStret(false), StructureType(0), Block(blockExpr) { 31 32 // Skip asm prefix, if any. 33 if (Name && Name[0] == '\01') 34 ++Name; 35 } 36 37 // Anchor the vtable to this translation unit. 38 CodeGenModule::ByrefHelpers::~ByrefHelpers() {} 39 40 /// Build the given block as a global block. 41 static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM, 42 const CGBlockInfo &blockInfo, 43 llvm::Constant *blockFn); 44 45 /// Build the helper function to copy a block. 46 static llvm::Constant *buildCopyHelper(CodeGenModule &CGM, 47 const CGBlockInfo &blockInfo) { 48 return CodeGenFunction(CGM).GenerateCopyHelperFunction(blockInfo); 49 } 50 51 /// Build the helper function to dipose of a block. 52 static llvm::Constant *buildDisposeHelper(CodeGenModule &CGM, 53 const CGBlockInfo &blockInfo) { 54 return CodeGenFunction(CGM).GenerateDestroyHelperFunction(blockInfo); 55 } 56 57 /// Build the block descriptor constant for a block. 58 static llvm::Constant *buildBlockDescriptor(CodeGenModule &CGM, 59 const CGBlockInfo &blockInfo) { 60 ASTContext &C = CGM.getContext(); 61 62 llvm::Type *ulong = CGM.getTypes().ConvertType(C.UnsignedLongTy); 63 llvm::Type *i8p = CGM.getTypes().ConvertType(C.VoidPtrTy); 64 65 SmallVector<llvm::Constant*, 6> elements; 66 67 // reserved 68 elements.push_back(llvm::ConstantInt::get(ulong, 0)); 69 70 // Size 71 // FIXME: What is the right way to say this doesn't fit? We should give 72 // a user diagnostic in that case. Better fix would be to change the 73 // API to size_t. 74 elements.push_back(llvm::ConstantInt::get(ulong, 75 blockInfo.BlockSize.getQuantity())); 76 77 // Optional copy/dispose helpers. 78 if (blockInfo.NeedsCopyDispose) { 79 // copy_func_helper_decl 80 elements.push_back(buildCopyHelper(CGM, blockInfo)); 81 82 // destroy_func_decl 83 elements.push_back(buildDisposeHelper(CGM, blockInfo)); 84 } 85 86 // Signature. Mandatory ObjC-style method descriptor @encode sequence. 87 std::string typeAtEncoding = 88 CGM.getContext().getObjCEncodingForBlock(blockInfo.getBlockExpr()); 89 elements.push_back(llvm::ConstantExpr::getBitCast( 90 CGM.GetAddrOfConstantCString(typeAtEncoding), i8p)); 91 92 // GC layout. 93 if (C.getLangOptions().ObjC1) 94 elements.push_back(CGM.getObjCRuntime().BuildGCBlockLayout(CGM, blockInfo)); 95 else 96 elements.push_back(llvm::Constant::getNullValue(i8p)); 97 98 llvm::Constant *init = llvm::ConstantStruct::getAnon(elements); 99 100 llvm::GlobalVariable *global = 101 new llvm::GlobalVariable(CGM.getModule(), init->getType(), true, 102 llvm::GlobalValue::InternalLinkage, 103 init, "__block_descriptor_tmp"); 104 105 return llvm::ConstantExpr::getBitCast(global, CGM.getBlockDescriptorType()); 106 } 107 108 /* 109 Purely notional variadic template describing the layout of a block. 110 111 template <class _ResultType, class... _ParamTypes, class... _CaptureTypes> 112 struct Block_literal { 113 /// Initialized to one of: 114 /// extern void *_NSConcreteStackBlock[]; 115 /// extern void *_NSConcreteGlobalBlock[]; 116 /// 117 /// In theory, we could start one off malloc'ed by setting 118 /// BLOCK_NEEDS_FREE, giving it a refcount of 1, and using 119 /// this isa: 120 /// extern void *_NSConcreteMallocBlock[]; 121 struct objc_class *isa; 122 123 /// These are the flags (with corresponding bit number) that the 124 /// compiler is actually supposed to know about. 125 /// 25. BLOCK_HAS_COPY_DISPOSE - indicates that the block 126 /// descriptor provides copy and dispose helper functions 127 /// 26. BLOCK_HAS_CXX_OBJ - indicates that there's a captured 128 /// object with a nontrivial destructor or copy constructor 129 /// 28. BLOCK_IS_GLOBAL - indicates that the block is allocated 130 /// as global memory 131 /// 29. BLOCK_USE_STRET - indicates that the block function 132 /// uses stret, which objc_msgSend needs to know about 133 /// 30. BLOCK_HAS_SIGNATURE - indicates that the block has an 134 /// @encoded signature string 135 /// And we're not supposed to manipulate these: 136 /// 24. BLOCK_NEEDS_FREE - indicates that the block has been moved 137 /// to malloc'ed memory 138 /// 27. BLOCK_IS_GC - indicates that the block has been moved to 139 /// to GC-allocated memory 140 /// Additionally, the bottom 16 bits are a reference count which 141 /// should be zero on the stack. 142 int flags; 143 144 /// Reserved; should be zero-initialized. 145 int reserved; 146 147 /// Function pointer generated from block literal. 148 _ResultType (*invoke)(Block_literal *, _ParamTypes...); 149 150 /// Block description metadata generated from block literal. 151 struct Block_descriptor *block_descriptor; 152 153 /// Captured values follow. 154 _CapturesTypes captures...; 155 }; 156 */ 157 158 /// The number of fields in a block header. 159 const unsigned BlockHeaderSize = 5; 160 161 namespace { 162 /// A chunk of data that we actually have to capture in the block. 163 struct BlockLayoutChunk { 164 CharUnits Alignment; 165 CharUnits Size; 166 const BlockDecl::Capture *Capture; // null for 'this' 167 llvm::Type *Type; 168 169 BlockLayoutChunk(CharUnits align, CharUnits size, 170 const BlockDecl::Capture *capture, 171 llvm::Type *type) 172 : Alignment(align), Size(size), Capture(capture), Type(type) {} 173 174 /// Tell the block info that this chunk has the given field index. 175 void setIndex(CGBlockInfo &info, unsigned index) { 176 if (!Capture) 177 info.CXXThisIndex = index; 178 else 179 info.Captures[Capture->getVariable()] 180 = CGBlockInfo::Capture::makeIndex(index); 181 } 182 }; 183 184 /// Order by descending alignment. 185 bool operator<(const BlockLayoutChunk &left, const BlockLayoutChunk &right) { 186 return left.Alignment > right.Alignment; 187 } 188 } 189 190 /// Determines if the given type is safe for constant capture in C++. 191 static bool isSafeForCXXConstantCapture(QualType type) { 192 const RecordType *recordType = 193 type->getBaseElementTypeUnsafe()->getAs<RecordType>(); 194 195 // Only records can be unsafe. 196 if (!recordType) return true; 197 198 const CXXRecordDecl *record = cast<CXXRecordDecl>(recordType->getDecl()); 199 200 // Maintain semantics for classes with non-trivial dtors or copy ctors. 201 if (!record->hasTrivialDestructor()) return false; 202 if (!record->hasTrivialCopyConstructor()) return false; 203 204 // Otherwise, we just have to make sure there aren't any mutable 205 // fields that might have changed since initialization. 206 return !record->hasMutableFields(); 207 } 208 209 /// It is illegal to modify a const object after initialization. 210 /// Therefore, if a const object has a constant initializer, we don't 211 /// actually need to keep storage for it in the block; we'll just 212 /// rematerialize it at the start of the block function. This is 213 /// acceptable because we make no promises about address stability of 214 /// captured variables. 215 static llvm::Constant *tryCaptureAsConstant(CodeGenModule &CGM, 216 const VarDecl *var) { 217 QualType type = var->getType(); 218 219 // We can only do this if the variable is const. 220 if (!type.isConstQualified()) return 0; 221 222 // Furthermore, in C++ we have to worry about mutable fields: 223 // C++ [dcl.type.cv]p4: 224 // Except that any class member declared mutable can be 225 // modified, any attempt to modify a const object during its 226 // lifetime results in undefined behavior. 227 if (CGM.getLangOptions().CPlusPlus && !isSafeForCXXConstantCapture(type)) 228 return 0; 229 230 // If the variable doesn't have any initializer (shouldn't this be 231 // invalid?), it's not clear what we should do. Maybe capture as 232 // zero? 233 const Expr *init = var->getInit(); 234 if (!init) return 0; 235 236 return CGM.EmitConstantExpr(init, var->getType()); 237 } 238 239 /// Get the low bit of a nonzero character count. This is the 240 /// alignment of the nth byte if the 0th byte is universally aligned. 241 static CharUnits getLowBit(CharUnits v) { 242 return CharUnits::fromQuantity(v.getQuantity() & (~v.getQuantity() + 1)); 243 } 244 245 static void initializeForBlockHeader(CodeGenModule &CGM, CGBlockInfo &info, 246 SmallVectorImpl<llvm::Type*> &elementTypes) { 247 ASTContext &C = CGM.getContext(); 248 249 // The header is basically a 'struct { void *; int; int; void *; void *; }'. 250 CharUnits ptrSize, ptrAlign, intSize, intAlign; 251 llvm::tie(ptrSize, ptrAlign) = C.getTypeInfoInChars(C.VoidPtrTy); 252 llvm::tie(intSize, intAlign) = C.getTypeInfoInChars(C.IntTy); 253 254 // Are there crazy embedded platforms where this isn't true? 255 assert(intSize <= ptrSize && "layout assumptions horribly violated"); 256 257 CharUnits headerSize = ptrSize; 258 if (2 * intSize < ptrAlign) headerSize += ptrSize; 259 else headerSize += 2 * intSize; 260 headerSize += 2 * ptrSize; 261 262 info.BlockAlign = ptrAlign; 263 info.BlockSize = headerSize; 264 265 assert(elementTypes.empty()); 266 llvm::Type *i8p = CGM.getTypes().ConvertType(C.VoidPtrTy); 267 llvm::Type *intTy = CGM.getTypes().ConvertType(C.IntTy); 268 elementTypes.push_back(i8p); 269 elementTypes.push_back(intTy); 270 elementTypes.push_back(intTy); 271 elementTypes.push_back(i8p); 272 elementTypes.push_back(CGM.getBlockDescriptorType()); 273 274 assert(elementTypes.size() == BlockHeaderSize); 275 } 276 277 /// Compute the layout of the given block. Attempts to lay the block 278 /// out with minimal space requirements. 279 static void computeBlockInfo(CodeGenModule &CGM, CGBlockInfo &info) { 280 ASTContext &C = CGM.getContext(); 281 const BlockDecl *block = info.getBlockDecl(); 282 283 SmallVector<llvm::Type*, 8> elementTypes; 284 initializeForBlockHeader(CGM, info, elementTypes); 285 286 if (!block->hasCaptures()) { 287 info.StructureType = 288 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); 289 info.CanBeGlobal = true; 290 return; 291 } 292 293 // Collect the layout chunks. 294 SmallVector<BlockLayoutChunk, 16> layout; 295 layout.reserve(block->capturesCXXThis() + 296 (block->capture_end() - block->capture_begin())); 297 298 CharUnits maxFieldAlign; 299 300 // First, 'this'. 301 if (block->capturesCXXThis()) { 302 const DeclContext *DC = block->getDeclContext(); 303 for (; isa<BlockDecl>(DC); DC = cast<BlockDecl>(DC)->getDeclContext()) 304 ; 305 QualType thisType; 306 if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(DC)) 307 thisType = C.getPointerType(C.getRecordType(RD)); 308 else 309 thisType = cast<CXXMethodDecl>(DC)->getThisType(C); 310 311 llvm::Type *llvmType = CGM.getTypes().ConvertType(thisType); 312 std::pair<CharUnits,CharUnits> tinfo 313 = CGM.getContext().getTypeInfoInChars(thisType); 314 maxFieldAlign = std::max(maxFieldAlign, tinfo.second); 315 316 layout.push_back(BlockLayoutChunk(tinfo.second, tinfo.first, 0, llvmType)); 317 } 318 319 // Next, all the block captures. 320 for (BlockDecl::capture_const_iterator ci = block->capture_begin(), 321 ce = block->capture_end(); ci != ce; ++ci) { 322 const VarDecl *variable = ci->getVariable(); 323 324 if (ci->isByRef()) { 325 // We have to copy/dispose of the __block reference. 326 info.NeedsCopyDispose = true; 327 328 // Just use void* instead of a pointer to the byref type. 329 QualType byRefPtrTy = C.VoidPtrTy; 330 331 llvm::Type *llvmType = CGM.getTypes().ConvertType(byRefPtrTy); 332 std::pair<CharUnits,CharUnits> tinfo 333 = CGM.getContext().getTypeInfoInChars(byRefPtrTy); 334 maxFieldAlign = std::max(maxFieldAlign, tinfo.second); 335 336 layout.push_back(BlockLayoutChunk(tinfo.second, tinfo.first, 337 &*ci, llvmType)); 338 continue; 339 } 340 341 // Otherwise, build a layout chunk with the size and alignment of 342 // the declaration. 343 if (llvm::Constant *constant = tryCaptureAsConstant(CGM, variable)) { 344 info.Captures[variable] = CGBlockInfo::Capture::makeConstant(constant); 345 continue; 346 } 347 348 // If we have a lifetime qualifier, honor it for capture purposes. 349 // That includes *not* copying it if it's __unsafe_unretained. 350 if (Qualifiers::ObjCLifetime lifetime 351 = variable->getType().getObjCLifetime()) { 352 switch (lifetime) { 353 case Qualifiers::OCL_None: llvm_unreachable("impossible"); 354 case Qualifiers::OCL_ExplicitNone: 355 case Qualifiers::OCL_Autoreleasing: 356 break; 357 358 case Qualifiers::OCL_Strong: 359 case Qualifiers::OCL_Weak: 360 info.NeedsCopyDispose = true; 361 } 362 363 // Block pointers require copy/dispose. So do Objective-C pointers. 364 } else if (variable->getType()->isObjCRetainableType()) { 365 info.NeedsCopyDispose = true; 366 367 // So do types that require non-trivial copy construction. 368 } else if (ci->hasCopyExpr()) { 369 info.NeedsCopyDispose = true; 370 info.HasCXXObject = true; 371 372 // And so do types with destructors. 373 } else if (CGM.getLangOptions().CPlusPlus) { 374 if (const CXXRecordDecl *record = 375 variable->getType()->getAsCXXRecordDecl()) { 376 if (!record->hasTrivialDestructor()) { 377 info.HasCXXObject = true; 378 info.NeedsCopyDispose = true; 379 } 380 } 381 } 382 383 CharUnits size = C.getTypeSizeInChars(variable->getType()); 384 CharUnits align = C.getDeclAlign(variable); 385 maxFieldAlign = std::max(maxFieldAlign, align); 386 387 llvm::Type *llvmType = 388 CGM.getTypes().ConvertTypeForMem(variable->getType()); 389 390 layout.push_back(BlockLayoutChunk(align, size, &*ci, llvmType)); 391 } 392 393 // If that was everything, we're done here. 394 if (layout.empty()) { 395 info.StructureType = 396 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); 397 info.CanBeGlobal = true; 398 return; 399 } 400 401 // Sort the layout by alignment. We have to use a stable sort here 402 // to get reproducible results. There should probably be an 403 // llvm::array_pod_stable_sort. 404 std::stable_sort(layout.begin(), layout.end()); 405 406 CharUnits &blockSize = info.BlockSize; 407 info.BlockAlign = std::max(maxFieldAlign, info.BlockAlign); 408 409 // Assuming that the first byte in the header is maximally aligned, 410 // get the alignment of the first byte following the header. 411 CharUnits endAlign = getLowBit(blockSize); 412 413 // If the end of the header isn't satisfactorily aligned for the 414 // maximum thing, look for things that are okay with the header-end 415 // alignment, and keep appending them until we get something that's 416 // aligned right. This algorithm is only guaranteed optimal if 417 // that condition is satisfied at some point; otherwise we can get 418 // things like: 419 // header // next byte has alignment 4 420 // something_with_size_5; // next byte has alignment 1 421 // something_with_alignment_8; 422 // which has 7 bytes of padding, as opposed to the naive solution 423 // which might have less (?). 424 if (endAlign < maxFieldAlign) { 425 SmallVectorImpl<BlockLayoutChunk>::iterator 426 li = layout.begin() + 1, le = layout.end(); 427 428 // Look for something that the header end is already 429 // satisfactorily aligned for. 430 for (; li != le && endAlign < li->Alignment; ++li) 431 ; 432 433 // If we found something that's naturally aligned for the end of 434 // the header, keep adding things... 435 if (li != le) { 436 SmallVectorImpl<BlockLayoutChunk>::iterator first = li; 437 for (; li != le; ++li) { 438 assert(endAlign >= li->Alignment); 439 440 li->setIndex(info, elementTypes.size()); 441 elementTypes.push_back(li->Type); 442 blockSize += li->Size; 443 endAlign = getLowBit(blockSize); 444 445 // ...until we get to the alignment of the maximum field. 446 if (endAlign >= maxFieldAlign) 447 break; 448 } 449 450 // Don't re-append everything we just appended. 451 layout.erase(first, li); 452 } 453 } 454 455 // At this point, we just have to add padding if the end align still 456 // isn't aligned right. 457 if (endAlign < maxFieldAlign) { 458 CharUnits padding = maxFieldAlign - endAlign; 459 460 elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty, 461 padding.getQuantity())); 462 blockSize += padding; 463 464 endAlign = getLowBit(blockSize); 465 assert(endAlign >= maxFieldAlign); 466 } 467 468 // Slam everything else on now. This works because they have 469 // strictly decreasing alignment and we expect that size is always a 470 // multiple of alignment. 471 for (SmallVectorImpl<BlockLayoutChunk>::iterator 472 li = layout.begin(), le = layout.end(); li != le; ++li) { 473 assert(endAlign >= li->Alignment); 474 li->setIndex(info, elementTypes.size()); 475 elementTypes.push_back(li->Type); 476 blockSize += li->Size; 477 endAlign = getLowBit(blockSize); 478 } 479 480 info.StructureType = 481 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); 482 } 483 484 /// Emit a block literal expression in the current function. 485 llvm::Value *CodeGenFunction::EmitBlockLiteral(const BlockExpr *blockExpr) { 486 std::string Name = CurFn->getName(); 487 CGBlockInfo blockInfo(blockExpr, Name.c_str()); 488 489 // Compute information about the layout, etc., of this block. 490 computeBlockInfo(CGM, blockInfo); 491 492 // Using that metadata, generate the actual block function. 493 llvm::Constant *blockFn 494 = CodeGenFunction(CGM).GenerateBlockFunction(CurGD, blockInfo, 495 CurFuncDecl, LocalDeclMap); 496 blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy); 497 498 // If there is nothing to capture, we can emit this as a global block. 499 if (blockInfo.CanBeGlobal) 500 return buildGlobalBlock(CGM, blockInfo, blockFn); 501 502 // Otherwise, we have to emit this as a local block. 503 504 llvm::Constant *isa = CGM.getNSConcreteStackBlock(); 505 isa = llvm::ConstantExpr::getBitCast(isa, VoidPtrTy); 506 507 // Build the block descriptor. 508 llvm::Constant *descriptor = buildBlockDescriptor(CGM, blockInfo); 509 510 llvm::Type *intTy = ConvertType(getContext().IntTy); 511 512 llvm::AllocaInst *blockAddr = 513 CreateTempAlloca(blockInfo.StructureType, "block"); 514 blockAddr->setAlignment(blockInfo.BlockAlign.getQuantity()); 515 516 // Compute the initial on-stack block flags. 517 BlockFlags flags = BLOCK_HAS_SIGNATURE; 518 if (blockInfo.NeedsCopyDispose) flags |= BLOCK_HAS_COPY_DISPOSE; 519 if (blockInfo.HasCXXObject) flags |= BLOCK_HAS_CXX_OBJ; 520 if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET; 521 522 // Initialize the block literal. 523 Builder.CreateStore(isa, Builder.CreateStructGEP(blockAddr, 0, "block.isa")); 524 Builder.CreateStore(llvm::ConstantInt::get(intTy, flags.getBitMask()), 525 Builder.CreateStructGEP(blockAddr, 1, "block.flags")); 526 Builder.CreateStore(llvm::ConstantInt::get(intTy, 0), 527 Builder.CreateStructGEP(blockAddr, 2, "block.reserved")); 528 Builder.CreateStore(blockFn, Builder.CreateStructGEP(blockAddr, 3, 529 "block.invoke")); 530 Builder.CreateStore(descriptor, Builder.CreateStructGEP(blockAddr, 4, 531 "block.descriptor")); 532 533 // Finally, capture all the values into the block. 534 const BlockDecl *blockDecl = blockInfo.getBlockDecl(); 535 536 // First, 'this'. 537 if (blockDecl->capturesCXXThis()) { 538 llvm::Value *addr = Builder.CreateStructGEP(blockAddr, 539 blockInfo.CXXThisIndex, 540 "block.captured-this.addr"); 541 Builder.CreateStore(LoadCXXThis(), addr); 542 } 543 544 // Next, captured variables. 545 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(), 546 ce = blockDecl->capture_end(); ci != ce; ++ci) { 547 const VarDecl *variable = ci->getVariable(); 548 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 549 550 // Ignore constant captures. 551 if (capture.isConstant()) continue; 552 553 QualType type = variable->getType(); 554 555 // This will be a [[type]]*, except that a byref entry will just be 556 // an i8**. 557 llvm::Value *blockField = 558 Builder.CreateStructGEP(blockAddr, capture.getIndex(), 559 "block.captured"); 560 561 // Compute the address of the thing we're going to move into the 562 // block literal. 563 llvm::Value *src; 564 if (ci->isNested()) { 565 // We need to use the capture from the enclosing block. 566 const CGBlockInfo::Capture &enclosingCapture = 567 BlockInfo->getCapture(variable); 568 569 // This is a [[type]]*, except that a byref entry wil just be an i8**. 570 src = Builder.CreateStructGEP(LoadBlockStruct(), 571 enclosingCapture.getIndex(), 572 "block.capture.addr"); 573 } else { 574 // This is a [[type]]*. 575 src = LocalDeclMap[variable]; 576 } 577 578 // For byrefs, we just write the pointer to the byref struct into 579 // the block field. There's no need to chase the forwarding 580 // pointer at this point, since we're building something that will 581 // live a shorter life than the stack byref anyway. 582 if (ci->isByRef()) { 583 // Get a void* that points to the byref struct. 584 if (ci->isNested()) 585 src = Builder.CreateLoad(src, "byref.capture"); 586 else 587 src = Builder.CreateBitCast(src, VoidPtrTy); 588 589 // Write that void* into the capture field. 590 Builder.CreateStore(src, blockField); 591 592 // If we have a copy constructor, evaluate that into the block field. 593 } else if (const Expr *copyExpr = ci->getCopyExpr()) { 594 EmitSynthesizedCXXCopyCtor(blockField, src, copyExpr); 595 596 // If it's a reference variable, copy the reference into the block field. 597 } else if (type->isReferenceType()) { 598 Builder.CreateStore(Builder.CreateLoad(src, "ref.val"), blockField); 599 600 // Otherwise, fake up a POD copy into the block field. 601 } else { 602 // Fake up a new variable so that EmitScalarInit doesn't think 603 // we're referring to the variable in its own initializer. 604 ImplicitParamDecl blockFieldPseudoVar(/*DC*/ 0, SourceLocation(), 605 /*name*/ 0, type); 606 607 // We use one of these or the other depending on whether the 608 // reference is nested. 609 DeclRefExpr notNested(const_cast<VarDecl*>(variable), type, VK_LValue, 610 SourceLocation()); 611 BlockDeclRefExpr nested(const_cast<VarDecl*>(variable), type, 612 VK_LValue, SourceLocation(), /*byref*/ false); 613 614 Expr *declRef = 615 (ci->isNested() ? static_cast<Expr*>(&nested) : ¬Nested); 616 617 ImplicitCastExpr l2r(ImplicitCastExpr::OnStack, type, CK_LValueToRValue, 618 declRef, VK_RValue); 619 EmitExprAsInit(&l2r, &blockFieldPseudoVar, 620 MakeAddrLValue(blockField, type, 621 getContext().getDeclAlign(variable) 622 .getQuantity()), 623 /*captured by init*/ false); 624 } 625 626 // Push a destructor if necessary. The semantics for when this 627 // actually gets run are really obscure. 628 if (!ci->isByRef()) { 629 switch (QualType::DestructionKind dtorKind = type.isDestructedType()) { 630 case QualType::DK_none: 631 break; 632 633 // Block captures count as local values and have imprecise semantics. 634 // They also can't be arrays, so need to worry about that. 635 case QualType::DK_objc_strong_lifetime: { 636 // This local is a GCC and MSVC compiler workaround. 637 Destroyer *destroyer = &destroyARCStrongImprecise; 638 pushDestroy(getCleanupKind(dtorKind), blockField, type, 639 *destroyer, /*useEHCleanupForArray*/ false); 640 break; 641 } 642 643 case QualType::DK_objc_weak_lifetime: 644 case QualType::DK_cxx_destructor: 645 pushDestroy(dtorKind, blockField, type); 646 break; 647 } 648 } 649 } 650 651 // Cast to the converted block-pointer type, which happens (somewhat 652 // unfortunately) to be a pointer to function type. 653 llvm::Value *result = 654 Builder.CreateBitCast(blockAddr, 655 ConvertType(blockInfo.getBlockExpr()->getType())); 656 657 return result; 658 } 659 660 661 llvm::Type *CodeGenModule::getBlockDescriptorType() { 662 if (BlockDescriptorType) 663 return BlockDescriptorType; 664 665 llvm::Type *UnsignedLongTy = 666 getTypes().ConvertType(getContext().UnsignedLongTy); 667 668 // struct __block_descriptor { 669 // unsigned long reserved; 670 // unsigned long block_size; 671 // 672 // // later, the following will be added 673 // 674 // struct { 675 // void (*copyHelper)(); 676 // void (*copyHelper)(); 677 // } helpers; // !!! optional 678 // 679 // const char *signature; // the block signature 680 // const char *layout; // reserved 681 // }; 682 BlockDescriptorType = 683 llvm::StructType::create("struct.__block_descriptor", 684 UnsignedLongTy, UnsignedLongTy, NULL); 685 686 // Now form a pointer to that. 687 BlockDescriptorType = llvm::PointerType::getUnqual(BlockDescriptorType); 688 return BlockDescriptorType; 689 } 690 691 llvm::Type *CodeGenModule::getGenericBlockLiteralType() { 692 if (GenericBlockLiteralType) 693 return GenericBlockLiteralType; 694 695 llvm::Type *BlockDescPtrTy = getBlockDescriptorType(); 696 697 // struct __block_literal_generic { 698 // void *__isa; 699 // int __flags; 700 // int __reserved; 701 // void (*__invoke)(void *); 702 // struct __block_descriptor *__descriptor; 703 // }; 704 GenericBlockLiteralType = 705 llvm::StructType::create("struct.__block_literal_generic", 706 VoidPtrTy, IntTy, IntTy, VoidPtrTy, 707 BlockDescPtrTy, NULL); 708 709 return GenericBlockLiteralType; 710 } 711 712 713 RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr* E, 714 ReturnValueSlot ReturnValue) { 715 const BlockPointerType *BPT = 716 E->getCallee()->getType()->getAs<BlockPointerType>(); 717 718 llvm::Value *Callee = EmitScalarExpr(E->getCallee()); 719 720 // Get a pointer to the generic block literal. 721 llvm::Type *BlockLiteralTy = 722 llvm::PointerType::getUnqual(CGM.getGenericBlockLiteralType()); 723 724 // Bitcast the callee to a block literal. 725 llvm::Value *BlockLiteral = 726 Builder.CreateBitCast(Callee, BlockLiteralTy, "block.literal"); 727 728 // Get the function pointer from the literal. 729 llvm::Value *FuncPtr = Builder.CreateStructGEP(BlockLiteral, 3); 730 731 BlockLiteral = Builder.CreateBitCast(BlockLiteral, VoidPtrTy); 732 733 // Add the block literal. 734 CallArgList Args; 735 Args.add(RValue::get(BlockLiteral), getContext().VoidPtrTy); 736 737 QualType FnType = BPT->getPointeeType(); 738 739 // And the rest of the arguments. 740 EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(), 741 E->arg_begin(), E->arg_end()); 742 743 // Load the function. 744 llvm::Value *Func = Builder.CreateLoad(FuncPtr); 745 746 const FunctionType *FuncTy = FnType->castAs<FunctionType>(); 747 const CGFunctionInfo &FnInfo = CGM.getTypes().getFunctionInfo(Args, FuncTy); 748 749 // Cast the function pointer to the right type. 750 llvm::Type *BlockFTy = 751 CGM.getTypes().GetFunctionType(FnInfo, false); 752 753 llvm::Type *BlockFTyPtr = llvm::PointerType::getUnqual(BlockFTy); 754 Func = Builder.CreateBitCast(Func, BlockFTyPtr); 755 756 // And call the block. 757 return EmitCall(FnInfo, Func, ReturnValue, Args); 758 } 759 760 llvm::Value *CodeGenFunction::GetAddrOfBlockDecl(const VarDecl *variable, 761 bool isByRef) { 762 assert(BlockInfo && "evaluating block ref without block information?"); 763 const CGBlockInfo::Capture &capture = BlockInfo->getCapture(variable); 764 765 // Handle constant captures. 766 if (capture.isConstant()) return LocalDeclMap[variable]; 767 768 llvm::Value *addr = 769 Builder.CreateStructGEP(LoadBlockStruct(), capture.getIndex(), 770 "block.capture.addr"); 771 772 if (isByRef) { 773 // addr should be a void** right now. Load, then cast the result 774 // to byref*. 775 776 addr = Builder.CreateLoad(addr); 777 llvm::PointerType *byrefPointerType 778 = llvm::PointerType::get(BuildByRefType(variable), 0); 779 addr = Builder.CreateBitCast(addr, byrefPointerType, 780 "byref.addr"); 781 782 // Follow the forwarding pointer. 783 addr = Builder.CreateStructGEP(addr, 1, "byref.forwarding"); 784 addr = Builder.CreateLoad(addr, "byref.addr.forwarded"); 785 786 // Cast back to byref* and GEP over to the actual object. 787 addr = Builder.CreateBitCast(addr, byrefPointerType); 788 addr = Builder.CreateStructGEP(addr, getByRefValueLLVMField(variable), 789 variable->getNameAsString()); 790 } 791 792 if (variable->getType()->isReferenceType()) 793 addr = Builder.CreateLoad(addr, "ref.tmp"); 794 795 return addr; 796 } 797 798 llvm::Constant * 799 CodeGenModule::GetAddrOfGlobalBlock(const BlockExpr *blockExpr, 800 const char *name) { 801 CGBlockInfo blockInfo(blockExpr, name); 802 803 // Compute information about the layout, etc., of this block. 804 computeBlockInfo(*this, blockInfo); 805 806 // Using that metadata, generate the actual block function. 807 llvm::Constant *blockFn; 808 { 809 llvm::DenseMap<const Decl*, llvm::Value*> LocalDeclMap; 810 blockFn = CodeGenFunction(*this).GenerateBlockFunction(GlobalDecl(), 811 blockInfo, 812 0, LocalDeclMap); 813 } 814 blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy); 815 816 return buildGlobalBlock(*this, blockInfo, blockFn); 817 } 818 819 static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM, 820 const CGBlockInfo &blockInfo, 821 llvm::Constant *blockFn) { 822 assert(blockInfo.CanBeGlobal); 823 824 // Generate the constants for the block literal initializer. 825 llvm::Constant *fields[BlockHeaderSize]; 826 827 // isa 828 fields[0] = CGM.getNSConcreteGlobalBlock(); 829 830 // __flags 831 BlockFlags flags = BLOCK_IS_GLOBAL | BLOCK_HAS_SIGNATURE; 832 if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET; 833 834 fields[1] = llvm::ConstantInt::get(CGM.IntTy, flags.getBitMask()); 835 836 // Reserved 837 fields[2] = llvm::Constant::getNullValue(CGM.IntTy); 838 839 // Function 840 fields[3] = blockFn; 841 842 // Descriptor 843 fields[4] = buildBlockDescriptor(CGM, blockInfo); 844 845 llvm::Constant *init = llvm::ConstantStruct::getAnon(fields); 846 847 llvm::GlobalVariable *literal = 848 new llvm::GlobalVariable(CGM.getModule(), 849 init->getType(), 850 /*constant*/ true, 851 llvm::GlobalVariable::InternalLinkage, 852 init, 853 "__block_literal_global"); 854 literal->setAlignment(blockInfo.BlockAlign.getQuantity()); 855 856 // Return a constant of the appropriately-casted type. 857 llvm::Type *requiredType = 858 CGM.getTypes().ConvertType(blockInfo.getBlockExpr()->getType()); 859 return llvm::ConstantExpr::getBitCast(literal, requiredType); 860 } 861 862 llvm::Function * 863 CodeGenFunction::GenerateBlockFunction(GlobalDecl GD, 864 const CGBlockInfo &blockInfo, 865 const Decl *outerFnDecl, 866 const DeclMapTy &ldm) { 867 const BlockDecl *blockDecl = blockInfo.getBlockDecl(); 868 869 // Check if we should generate debug info for this block function. 870 if (CGM.getModuleDebugInfo()) 871 DebugInfo = CGM.getModuleDebugInfo(); 872 873 BlockInfo = &blockInfo; 874 875 // Arrange for local static and local extern declarations to appear 876 // to be local to this function as well, in case they're directly 877 // referenced in a block. 878 for (DeclMapTy::const_iterator i = ldm.begin(), e = ldm.end(); i != e; ++i) { 879 const VarDecl *var = dyn_cast<VarDecl>(i->first); 880 if (var && !var->hasLocalStorage()) 881 LocalDeclMap[var] = i->second; 882 } 883 884 // Begin building the function declaration. 885 886 // Build the argument list. 887 FunctionArgList args; 888 889 // The first argument is the block pointer. Just take it as a void* 890 // and cast it later. 891 QualType selfTy = getContext().VoidPtrTy; 892 IdentifierInfo *II = &CGM.getContext().Idents.get(".block_descriptor"); 893 894 ImplicitParamDecl selfDecl(const_cast<BlockDecl*>(blockDecl), 895 SourceLocation(), II, selfTy); 896 args.push_back(&selfDecl); 897 898 // Now add the rest of the parameters. 899 for (BlockDecl::param_const_iterator i = blockDecl->param_begin(), 900 e = blockDecl->param_end(); i != e; ++i) 901 args.push_back(*i); 902 903 // Create the function declaration. 904 const FunctionProtoType *fnType = 905 cast<FunctionProtoType>(blockInfo.getBlockExpr()->getFunctionType()); 906 const CGFunctionInfo &fnInfo = 907 CGM.getTypes().getFunctionInfo(fnType->getResultType(), args, 908 fnType->getExtInfo()); 909 if (CGM.ReturnTypeUsesSRet(fnInfo)) 910 blockInfo.UsesStret = true; 911 912 llvm::FunctionType *fnLLVMType = 913 CGM.getTypes().GetFunctionType(fnInfo, fnType->isVariadic()); 914 915 MangleBuffer name; 916 CGM.getBlockMangledName(GD, name, blockDecl); 917 llvm::Function *fn = 918 llvm::Function::Create(fnLLVMType, llvm::GlobalValue::InternalLinkage, 919 name.getString(), &CGM.getModule()); 920 CGM.SetInternalFunctionAttributes(blockDecl, fn, fnInfo); 921 922 // Begin generating the function. 923 StartFunction(blockDecl, fnType->getResultType(), fn, fnInfo, args, 924 blockInfo.getBlockExpr()->getBody()->getLocStart()); 925 CurFuncDecl = outerFnDecl; // StartFunction sets this to blockDecl 926 927 // Okay. Undo some of what StartFunction did. 928 929 // Pull the 'self' reference out of the local decl map. 930 llvm::Value *blockAddr = LocalDeclMap[&selfDecl]; 931 LocalDeclMap.erase(&selfDecl); 932 BlockPointer = Builder.CreateBitCast(blockAddr, 933 blockInfo.StructureType->getPointerTo(), 934 "block"); 935 936 // If we have a C++ 'this' reference, go ahead and force it into 937 // existence now. 938 if (blockDecl->capturesCXXThis()) { 939 llvm::Value *addr = Builder.CreateStructGEP(BlockPointer, 940 blockInfo.CXXThisIndex, 941 "block.captured-this"); 942 CXXThisValue = Builder.CreateLoad(addr, "this"); 943 } 944 945 // LoadObjCSelf() expects there to be an entry for 'self' in LocalDeclMap; 946 // appease it. 947 if (const ObjCMethodDecl *method 948 = dyn_cast_or_null<ObjCMethodDecl>(CurFuncDecl)) { 949 const VarDecl *self = method->getSelfDecl(); 950 951 // There might not be a capture for 'self', but if there is... 952 if (blockInfo.Captures.count(self)) { 953 const CGBlockInfo::Capture &capture = blockInfo.getCapture(self); 954 llvm::Value *selfAddr = Builder.CreateStructGEP(BlockPointer, 955 capture.getIndex(), 956 "block.captured-self"); 957 LocalDeclMap[self] = selfAddr; 958 } 959 } 960 961 // Also force all the constant captures. 962 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(), 963 ce = blockDecl->capture_end(); ci != ce; ++ci) { 964 const VarDecl *variable = ci->getVariable(); 965 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 966 if (!capture.isConstant()) continue; 967 968 unsigned align = getContext().getDeclAlign(variable).getQuantity(); 969 970 llvm::AllocaInst *alloca = 971 CreateMemTemp(variable->getType(), "block.captured-const"); 972 alloca->setAlignment(align); 973 974 Builder.CreateStore(capture.getConstant(), alloca, align); 975 976 LocalDeclMap[variable] = alloca; 977 } 978 979 // Save a spot to insert the debug information for all the BlockDeclRefDecls. 980 llvm::BasicBlock *entry = Builder.GetInsertBlock(); 981 llvm::BasicBlock::iterator entry_ptr = Builder.GetInsertPoint(); 982 --entry_ptr; 983 984 EmitStmt(blockDecl->getBody()); 985 986 // Remember where we were... 987 llvm::BasicBlock *resume = Builder.GetInsertBlock(); 988 989 // Go back to the entry. 990 ++entry_ptr; 991 Builder.SetInsertPoint(entry, entry_ptr); 992 993 // Emit debug information for all the BlockDeclRefDecls. 994 // FIXME: also for 'this' 995 if (CGDebugInfo *DI = getDebugInfo()) { 996 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(), 997 ce = blockDecl->capture_end(); ci != ce; ++ci) { 998 const VarDecl *variable = ci->getVariable(); 999 DI->EmitLocation(Builder, variable->getLocation()); 1000 1001 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 1002 if (capture.isConstant()) { 1003 DI->EmitDeclareOfAutoVariable(variable, LocalDeclMap[variable], 1004 Builder); 1005 continue; 1006 } 1007 1008 DI->EmitDeclareOfBlockDeclRefVariable(variable, BlockPointer, 1009 Builder, blockInfo); 1010 } 1011 } 1012 1013 // And resume where we left off. 1014 if (resume == 0) 1015 Builder.ClearInsertionPoint(); 1016 else 1017 Builder.SetInsertPoint(resume); 1018 1019 FinishFunction(cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc()); 1020 1021 return fn; 1022 } 1023 1024 /* 1025 notes.push_back(HelperInfo()); 1026 HelperInfo ¬e = notes.back(); 1027 note.index = capture.getIndex(); 1028 note.RequiresCopying = (ci->hasCopyExpr() || BlockRequiresCopying(type)); 1029 note.cxxbar_import = ci->getCopyExpr(); 1030 1031 if (ci->isByRef()) { 1032 note.flag = BLOCK_FIELD_IS_BYREF; 1033 if (type.isObjCGCWeak()) 1034 note.flag |= BLOCK_FIELD_IS_WEAK; 1035 } else if (type->isBlockPointerType()) { 1036 note.flag = BLOCK_FIELD_IS_BLOCK; 1037 } else { 1038 note.flag = BLOCK_FIELD_IS_OBJECT; 1039 } 1040 */ 1041 1042 1043 1044 llvm::Constant * 1045 CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) { 1046 ASTContext &C = getContext(); 1047 1048 FunctionArgList args; 1049 ImplicitParamDecl dstDecl(0, SourceLocation(), 0, C.VoidPtrTy); 1050 args.push_back(&dstDecl); 1051 ImplicitParamDecl srcDecl(0, SourceLocation(), 0, C.VoidPtrTy); 1052 args.push_back(&srcDecl); 1053 1054 const CGFunctionInfo &FI = 1055 CGM.getTypes().getFunctionInfo(C.VoidTy, args, FunctionType::ExtInfo()); 1056 1057 // FIXME: it would be nice if these were mergeable with things with 1058 // identical semantics. 1059 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI, false); 1060 1061 llvm::Function *Fn = 1062 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, 1063 "__copy_helper_block_", &CGM.getModule()); 1064 1065 IdentifierInfo *II 1066 = &CGM.getContext().Idents.get("__copy_helper_block_"); 1067 1068 // Check if we should generate debug info for this block helper function. 1069 if (CGM.getModuleDebugInfo()) 1070 DebugInfo = CGM.getModuleDebugInfo(); 1071 1072 FunctionDecl *FD = FunctionDecl::Create(C, 1073 C.getTranslationUnitDecl(), 1074 SourceLocation(), 1075 SourceLocation(), II, C.VoidTy, 0, 1076 SC_Static, 1077 SC_None, 1078 false, 1079 true); 1080 StartFunction(FD, C.VoidTy, Fn, FI, args, SourceLocation()); 1081 1082 llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo(); 1083 1084 llvm::Value *src = GetAddrOfLocalVar(&srcDecl); 1085 src = Builder.CreateLoad(src); 1086 src = Builder.CreateBitCast(src, structPtrTy, "block.source"); 1087 1088 llvm::Value *dst = GetAddrOfLocalVar(&dstDecl); 1089 dst = Builder.CreateLoad(dst); 1090 dst = Builder.CreateBitCast(dst, structPtrTy, "block.dest"); 1091 1092 const BlockDecl *blockDecl = blockInfo.getBlockDecl(); 1093 1094 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(), 1095 ce = blockDecl->capture_end(); ci != ce; ++ci) { 1096 const VarDecl *variable = ci->getVariable(); 1097 QualType type = variable->getType(); 1098 1099 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 1100 if (capture.isConstant()) continue; 1101 1102 const Expr *copyExpr = ci->getCopyExpr(); 1103 BlockFieldFlags flags; 1104 1105 bool isARCWeakCapture = false; 1106 1107 if (copyExpr) { 1108 assert(!ci->isByRef()); 1109 // don't bother computing flags 1110 1111 } else if (ci->isByRef()) { 1112 flags = BLOCK_FIELD_IS_BYREF; 1113 if (type.isObjCGCWeak()) 1114 flags |= BLOCK_FIELD_IS_WEAK; 1115 1116 } else if (type->isObjCRetainableType()) { 1117 flags = BLOCK_FIELD_IS_OBJECT; 1118 if (type->isBlockPointerType()) 1119 flags = BLOCK_FIELD_IS_BLOCK; 1120 1121 // Special rules for ARC captures: 1122 if (getLangOptions().ObjCAutoRefCount) { 1123 Qualifiers qs = type.getQualifiers(); 1124 1125 // Don't generate special copy logic for a captured object 1126 // unless it's __strong or __weak. 1127 if (!qs.hasStrongOrWeakObjCLifetime()) 1128 continue; 1129 1130 // Support __weak direct captures. 1131 if (qs.getObjCLifetime() == Qualifiers::OCL_Weak) 1132 isARCWeakCapture = true; 1133 } 1134 } else { 1135 continue; 1136 } 1137 1138 unsigned index = capture.getIndex(); 1139 llvm::Value *srcField = Builder.CreateStructGEP(src, index); 1140 llvm::Value *dstField = Builder.CreateStructGEP(dst, index); 1141 1142 // If there's an explicit copy expression, we do that. 1143 if (copyExpr) { 1144 EmitSynthesizedCXXCopyCtor(dstField, srcField, copyExpr); 1145 } else if (isARCWeakCapture) { 1146 EmitARCCopyWeak(dstField, srcField); 1147 } else { 1148 llvm::Value *srcValue = Builder.CreateLoad(srcField, "blockcopy.src"); 1149 srcValue = Builder.CreateBitCast(srcValue, VoidPtrTy); 1150 llvm::Value *dstAddr = Builder.CreateBitCast(dstField, VoidPtrTy); 1151 Builder.CreateCall3(CGM.getBlockObjectAssign(), dstAddr, srcValue, 1152 llvm::ConstantInt::get(Int32Ty, flags.getBitMask())); 1153 } 1154 } 1155 1156 FinishFunction(); 1157 1158 return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy); 1159 } 1160 1161 llvm::Constant * 1162 CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) { 1163 ASTContext &C = getContext(); 1164 1165 FunctionArgList args; 1166 ImplicitParamDecl srcDecl(0, SourceLocation(), 0, C.VoidPtrTy); 1167 args.push_back(&srcDecl); 1168 1169 const CGFunctionInfo &FI = 1170 CGM.getTypes().getFunctionInfo(C.VoidTy, args, FunctionType::ExtInfo()); 1171 1172 // FIXME: We'd like to put these into a mergable by content, with 1173 // internal linkage. 1174 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI, false); 1175 1176 llvm::Function *Fn = 1177 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, 1178 "__destroy_helper_block_", &CGM.getModule()); 1179 1180 // Check if we should generate debug info for this block destroy function. 1181 if (CGM.getModuleDebugInfo()) 1182 DebugInfo = CGM.getModuleDebugInfo(); 1183 1184 IdentifierInfo *II 1185 = &CGM.getContext().Idents.get("__destroy_helper_block_"); 1186 1187 FunctionDecl *FD = FunctionDecl::Create(C, C.getTranslationUnitDecl(), 1188 SourceLocation(), 1189 SourceLocation(), II, C.VoidTy, 0, 1190 SC_Static, 1191 SC_None, 1192 false, true); 1193 StartFunction(FD, C.VoidTy, Fn, FI, args, SourceLocation()); 1194 1195 llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo(); 1196 1197 llvm::Value *src = GetAddrOfLocalVar(&srcDecl); 1198 src = Builder.CreateLoad(src); 1199 src = Builder.CreateBitCast(src, structPtrTy, "block"); 1200 1201 const BlockDecl *blockDecl = blockInfo.getBlockDecl(); 1202 1203 CodeGenFunction::RunCleanupsScope cleanups(*this); 1204 1205 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(), 1206 ce = blockDecl->capture_end(); ci != ce; ++ci) { 1207 const VarDecl *variable = ci->getVariable(); 1208 QualType type = variable->getType(); 1209 1210 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 1211 if (capture.isConstant()) continue; 1212 1213 BlockFieldFlags flags; 1214 const CXXDestructorDecl *dtor = 0; 1215 1216 bool isARCWeakCapture = false; 1217 1218 if (ci->isByRef()) { 1219 flags = BLOCK_FIELD_IS_BYREF; 1220 if (type.isObjCGCWeak()) 1221 flags |= BLOCK_FIELD_IS_WEAK; 1222 } else if (const CXXRecordDecl *record = type->getAsCXXRecordDecl()) { 1223 if (record->hasTrivialDestructor()) 1224 continue; 1225 dtor = record->getDestructor(); 1226 } else if (type->isObjCRetainableType()) { 1227 flags = BLOCK_FIELD_IS_OBJECT; 1228 if (type->isBlockPointerType()) 1229 flags = BLOCK_FIELD_IS_BLOCK; 1230 1231 // Special rules for ARC captures. 1232 if (getLangOptions().ObjCAutoRefCount) { 1233 Qualifiers qs = type.getQualifiers(); 1234 1235 // Don't generate special dispose logic for a captured object 1236 // unless it's __strong or __weak. 1237 if (!qs.hasStrongOrWeakObjCLifetime()) 1238 continue; 1239 1240 // Support __weak direct captures. 1241 if (qs.getObjCLifetime() == Qualifiers::OCL_Weak) 1242 isARCWeakCapture = true; 1243 } 1244 } else { 1245 continue; 1246 } 1247 1248 unsigned index = capture.getIndex(); 1249 llvm::Value *srcField = Builder.CreateStructGEP(src, index); 1250 1251 // If there's an explicit copy expression, we do that. 1252 if (dtor) { 1253 PushDestructorCleanup(dtor, srcField); 1254 1255 // If this is a __weak capture, emit the release directly. 1256 } else if (isARCWeakCapture) { 1257 EmitARCDestroyWeak(srcField); 1258 1259 // Otherwise we call _Block_object_dispose. It wouldn't be too 1260 // hard to just emit this as a cleanup if we wanted to make sure 1261 // that things were done in reverse. 1262 } else { 1263 llvm::Value *value = Builder.CreateLoad(srcField); 1264 value = Builder.CreateBitCast(value, VoidPtrTy); 1265 BuildBlockRelease(value, flags); 1266 } 1267 } 1268 1269 cleanups.ForceCleanup(); 1270 1271 FinishFunction(); 1272 1273 return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy); 1274 } 1275 1276 namespace { 1277 1278 /// Emits the copy/dispose helper functions for a __block object of id type. 1279 class ObjectByrefHelpers : public CodeGenModule::ByrefHelpers { 1280 BlockFieldFlags Flags; 1281 1282 public: 1283 ObjectByrefHelpers(CharUnits alignment, BlockFieldFlags flags) 1284 : ByrefHelpers(alignment), Flags(flags) {} 1285 1286 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1287 llvm::Value *srcField) { 1288 destField = CGF.Builder.CreateBitCast(destField, CGF.VoidPtrTy); 1289 1290 srcField = CGF.Builder.CreateBitCast(srcField, CGF.VoidPtrPtrTy); 1291 llvm::Value *srcValue = CGF.Builder.CreateLoad(srcField); 1292 1293 unsigned flags = (Flags | BLOCK_BYREF_CALLER).getBitMask(); 1294 1295 llvm::Value *flagsVal = llvm::ConstantInt::get(CGF.Int32Ty, flags); 1296 llvm::Value *fn = CGF.CGM.getBlockObjectAssign(); 1297 CGF.Builder.CreateCall3(fn, destField, srcValue, flagsVal); 1298 } 1299 1300 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) { 1301 field = CGF.Builder.CreateBitCast(field, CGF.Int8PtrTy->getPointerTo(0)); 1302 llvm::Value *value = CGF.Builder.CreateLoad(field); 1303 1304 CGF.BuildBlockRelease(value, Flags | BLOCK_BYREF_CALLER); 1305 } 1306 1307 void profileImpl(llvm::FoldingSetNodeID &id) const { 1308 id.AddInteger(Flags.getBitMask()); 1309 } 1310 }; 1311 1312 /// Emits the copy/dispose helpers for an ARC __block __weak variable. 1313 class ARCWeakByrefHelpers : public CodeGenModule::ByrefHelpers { 1314 public: 1315 ARCWeakByrefHelpers(CharUnits alignment) : ByrefHelpers(alignment) {} 1316 1317 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1318 llvm::Value *srcField) { 1319 CGF.EmitARCMoveWeak(destField, srcField); 1320 } 1321 1322 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) { 1323 CGF.EmitARCDestroyWeak(field); 1324 } 1325 1326 void profileImpl(llvm::FoldingSetNodeID &id) const { 1327 // 0 is distinguishable from all pointers and byref flags 1328 id.AddInteger(0); 1329 } 1330 }; 1331 1332 /// Emits the copy/dispose helpers for an ARC __block __strong variable 1333 /// that's not of block-pointer type. 1334 class ARCStrongByrefHelpers : public CodeGenModule::ByrefHelpers { 1335 public: 1336 ARCStrongByrefHelpers(CharUnits alignment) : ByrefHelpers(alignment) {} 1337 1338 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1339 llvm::Value *srcField) { 1340 // Do a "move" by copying the value and then zeroing out the old 1341 // variable. 1342 1343 llvm::Value *value = CGF.Builder.CreateLoad(srcField); 1344 llvm::Value *null = 1345 llvm::ConstantPointerNull::get(cast<llvm::PointerType>(value->getType())); 1346 CGF.Builder.CreateStore(value, destField); 1347 CGF.Builder.CreateStore(null, srcField); 1348 } 1349 1350 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) { 1351 llvm::Value *value = CGF.Builder.CreateLoad(field); 1352 CGF.EmitARCRelease(value, /*precise*/ false); 1353 } 1354 1355 void profileImpl(llvm::FoldingSetNodeID &id) const { 1356 // 1 is distinguishable from all pointers and byref flags 1357 id.AddInteger(1); 1358 } 1359 }; 1360 1361 /// Emits the copy/dispose helpers for a __block variable with a 1362 /// nontrivial copy constructor or destructor. 1363 class CXXByrefHelpers : public CodeGenModule::ByrefHelpers { 1364 QualType VarType; 1365 const Expr *CopyExpr; 1366 1367 public: 1368 CXXByrefHelpers(CharUnits alignment, QualType type, 1369 const Expr *copyExpr) 1370 : ByrefHelpers(alignment), VarType(type), CopyExpr(copyExpr) {} 1371 1372 bool needsCopy() const { return CopyExpr != 0; } 1373 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1374 llvm::Value *srcField) { 1375 if (!CopyExpr) return; 1376 CGF.EmitSynthesizedCXXCopyCtor(destField, srcField, CopyExpr); 1377 } 1378 1379 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) { 1380 EHScopeStack::stable_iterator cleanupDepth = CGF.EHStack.stable_begin(); 1381 CGF.PushDestructorCleanup(VarType, field); 1382 CGF.PopCleanupBlocks(cleanupDepth); 1383 } 1384 1385 void profileImpl(llvm::FoldingSetNodeID &id) const { 1386 id.AddPointer(VarType.getCanonicalType().getAsOpaquePtr()); 1387 } 1388 }; 1389 } // end anonymous namespace 1390 1391 static llvm::Constant * 1392 generateByrefCopyHelper(CodeGenFunction &CGF, 1393 llvm::StructType &byrefType, 1394 CodeGenModule::ByrefHelpers &byrefInfo) { 1395 ASTContext &Context = CGF.getContext(); 1396 1397 QualType R = Context.VoidTy; 1398 1399 FunctionArgList args; 1400 ImplicitParamDecl dst(0, SourceLocation(), 0, Context.VoidPtrTy); 1401 args.push_back(&dst); 1402 1403 ImplicitParamDecl src(0, SourceLocation(), 0, Context.VoidPtrTy); 1404 args.push_back(&src); 1405 1406 const CGFunctionInfo &FI = 1407 CGF.CGM.getTypes().getFunctionInfo(R, args, FunctionType::ExtInfo()); 1408 1409 CodeGenTypes &Types = CGF.CGM.getTypes(); 1410 llvm::FunctionType *LTy = Types.GetFunctionType(FI, false); 1411 1412 // FIXME: We'd like to put these into a mergable by content, with 1413 // internal linkage. 1414 llvm::Function *Fn = 1415 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, 1416 "__Block_byref_object_copy_", &CGF.CGM.getModule()); 1417 1418 IdentifierInfo *II 1419 = &Context.Idents.get("__Block_byref_object_copy_"); 1420 1421 FunctionDecl *FD = FunctionDecl::Create(Context, 1422 Context.getTranslationUnitDecl(), 1423 SourceLocation(), 1424 SourceLocation(), II, R, 0, 1425 SC_Static, 1426 SC_None, 1427 false, true); 1428 1429 CGF.StartFunction(FD, R, Fn, FI, args, SourceLocation()); 1430 1431 if (byrefInfo.needsCopy()) { 1432 llvm::Type *byrefPtrType = byrefType.getPointerTo(0); 1433 1434 // dst->x 1435 llvm::Value *destField = CGF.GetAddrOfLocalVar(&dst); 1436 destField = CGF.Builder.CreateLoad(destField); 1437 destField = CGF.Builder.CreateBitCast(destField, byrefPtrType); 1438 destField = CGF.Builder.CreateStructGEP(destField, 6, "x"); 1439 1440 // src->x 1441 llvm::Value *srcField = CGF.GetAddrOfLocalVar(&src); 1442 srcField = CGF.Builder.CreateLoad(srcField); 1443 srcField = CGF.Builder.CreateBitCast(srcField, byrefPtrType); 1444 srcField = CGF.Builder.CreateStructGEP(srcField, 6, "x"); 1445 1446 byrefInfo.emitCopy(CGF, destField, srcField); 1447 } 1448 1449 CGF.FinishFunction(); 1450 1451 return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy); 1452 } 1453 1454 /// Build the copy helper for a __block variable. 1455 static llvm::Constant *buildByrefCopyHelper(CodeGenModule &CGM, 1456 llvm::StructType &byrefType, 1457 CodeGenModule::ByrefHelpers &info) { 1458 CodeGenFunction CGF(CGM); 1459 return generateByrefCopyHelper(CGF, byrefType, info); 1460 } 1461 1462 /// Generate code for a __block variable's dispose helper. 1463 static llvm::Constant * 1464 generateByrefDisposeHelper(CodeGenFunction &CGF, 1465 llvm::StructType &byrefType, 1466 CodeGenModule::ByrefHelpers &byrefInfo) { 1467 ASTContext &Context = CGF.getContext(); 1468 QualType R = Context.VoidTy; 1469 1470 FunctionArgList args; 1471 ImplicitParamDecl src(0, SourceLocation(), 0, Context.VoidPtrTy); 1472 args.push_back(&src); 1473 1474 const CGFunctionInfo &FI = 1475 CGF.CGM.getTypes().getFunctionInfo(R, args, FunctionType::ExtInfo()); 1476 1477 CodeGenTypes &Types = CGF.CGM.getTypes(); 1478 llvm::FunctionType *LTy = Types.GetFunctionType(FI, false); 1479 1480 // FIXME: We'd like to put these into a mergable by content, with 1481 // internal linkage. 1482 llvm::Function *Fn = 1483 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, 1484 "__Block_byref_object_dispose_", 1485 &CGF.CGM.getModule()); 1486 1487 IdentifierInfo *II 1488 = &Context.Idents.get("__Block_byref_object_dispose_"); 1489 1490 FunctionDecl *FD = FunctionDecl::Create(Context, 1491 Context.getTranslationUnitDecl(), 1492 SourceLocation(), 1493 SourceLocation(), II, R, 0, 1494 SC_Static, 1495 SC_None, 1496 false, true); 1497 CGF.StartFunction(FD, R, Fn, FI, args, SourceLocation()); 1498 1499 if (byrefInfo.needsDispose()) { 1500 llvm::Value *V = CGF.GetAddrOfLocalVar(&src); 1501 V = CGF.Builder.CreateLoad(V); 1502 V = CGF.Builder.CreateBitCast(V, byrefType.getPointerTo(0)); 1503 V = CGF.Builder.CreateStructGEP(V, 6, "x"); 1504 1505 byrefInfo.emitDispose(CGF, V); 1506 } 1507 1508 CGF.FinishFunction(); 1509 1510 return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy); 1511 } 1512 1513 /// Build the dispose helper for a __block variable. 1514 static llvm::Constant *buildByrefDisposeHelper(CodeGenModule &CGM, 1515 llvm::StructType &byrefType, 1516 CodeGenModule::ByrefHelpers &info) { 1517 CodeGenFunction CGF(CGM); 1518 return generateByrefDisposeHelper(CGF, byrefType, info); 1519 } 1520 1521 /// 1522 template <class T> static T *buildByrefHelpers(CodeGenModule &CGM, 1523 llvm::StructType &byrefTy, 1524 T &byrefInfo) { 1525 // Increase the field's alignment to be at least pointer alignment, 1526 // since the layout of the byref struct will guarantee at least that. 1527 byrefInfo.Alignment = std::max(byrefInfo.Alignment, 1528 CharUnits::fromQuantity(CGM.PointerAlignInBytes)); 1529 1530 llvm::FoldingSetNodeID id; 1531 byrefInfo.Profile(id); 1532 1533 void *insertPos; 1534 CodeGenModule::ByrefHelpers *node 1535 = CGM.ByrefHelpersCache.FindNodeOrInsertPos(id, insertPos); 1536 if (node) return static_cast<T*>(node); 1537 1538 byrefInfo.CopyHelper = buildByrefCopyHelper(CGM, byrefTy, byrefInfo); 1539 byrefInfo.DisposeHelper = buildByrefDisposeHelper(CGM, byrefTy, byrefInfo); 1540 1541 T *copy = new (CGM.getContext()) T(byrefInfo); 1542 CGM.ByrefHelpersCache.InsertNode(copy, insertPos); 1543 return copy; 1544 } 1545 1546 CodeGenModule::ByrefHelpers * 1547 CodeGenFunction::buildByrefHelpers(llvm::StructType &byrefType, 1548 const AutoVarEmission &emission) { 1549 const VarDecl &var = *emission.Variable; 1550 QualType type = var.getType(); 1551 1552 if (const CXXRecordDecl *record = type->getAsCXXRecordDecl()) { 1553 const Expr *copyExpr = CGM.getContext().getBlockVarCopyInits(&var); 1554 if (!copyExpr && record->hasTrivialDestructor()) return 0; 1555 1556 CXXByrefHelpers byrefInfo(emission.Alignment, type, copyExpr); 1557 return ::buildByrefHelpers(CGM, byrefType, byrefInfo); 1558 } 1559 1560 // Otherwise, if we don't have a retainable type, there's nothing to do. 1561 // that the runtime does extra copies. 1562 if (!type->isObjCRetainableType()) return 0; 1563 1564 Qualifiers qs = type.getQualifiers(); 1565 1566 // If we have lifetime, that dominates. 1567 if (Qualifiers::ObjCLifetime lifetime = qs.getObjCLifetime()) { 1568 assert(getLangOptions().ObjCAutoRefCount); 1569 1570 switch (lifetime) { 1571 case Qualifiers::OCL_None: llvm_unreachable("impossible"); 1572 1573 // These are just bits as far as the runtime is concerned. 1574 case Qualifiers::OCL_ExplicitNone: 1575 case Qualifiers::OCL_Autoreleasing: 1576 return 0; 1577 1578 // Tell the runtime that this is ARC __weak, called by the 1579 // byref routines. 1580 case Qualifiers::OCL_Weak: { 1581 ARCWeakByrefHelpers byrefInfo(emission.Alignment); 1582 return ::buildByrefHelpers(CGM, byrefType, byrefInfo); 1583 } 1584 1585 // ARC __strong __block variables need to be retained. 1586 case Qualifiers::OCL_Strong: 1587 // Block-pointers need to be _Block_copy'ed, so we let the 1588 // runtime be in charge. But we can't use the code below 1589 // because we don't want to set BYREF_CALLER, which will 1590 // just make the runtime ignore us. 1591 if (type->isBlockPointerType()) { 1592 BlockFieldFlags flags = BLOCK_FIELD_IS_BLOCK; 1593 ObjectByrefHelpers byrefInfo(emission.Alignment, flags); 1594 return ::buildByrefHelpers(CGM, byrefType, byrefInfo); 1595 1596 // Otherwise, we transfer ownership of the retain from the stack 1597 // to the heap. 1598 } else { 1599 ARCStrongByrefHelpers byrefInfo(emission.Alignment); 1600 return ::buildByrefHelpers(CGM, byrefType, byrefInfo); 1601 } 1602 } 1603 llvm_unreachable("fell out of lifetime switch!"); 1604 } 1605 1606 BlockFieldFlags flags; 1607 if (type->isBlockPointerType()) { 1608 flags |= BLOCK_FIELD_IS_BLOCK; 1609 } else if (CGM.getContext().isObjCNSObjectType(type) || 1610 type->isObjCObjectPointerType()) { 1611 flags |= BLOCK_FIELD_IS_OBJECT; 1612 } else { 1613 return 0; 1614 } 1615 1616 if (type.isObjCGCWeak()) 1617 flags |= BLOCK_FIELD_IS_WEAK; 1618 1619 ObjectByrefHelpers byrefInfo(emission.Alignment, flags); 1620 return ::buildByrefHelpers(CGM, byrefType, byrefInfo); 1621 } 1622 1623 unsigned CodeGenFunction::getByRefValueLLVMField(const ValueDecl *VD) const { 1624 assert(ByRefValueInfo.count(VD) && "Did not find value!"); 1625 1626 return ByRefValueInfo.find(VD)->second.second; 1627 } 1628 1629 llvm::Value *CodeGenFunction::BuildBlockByrefAddress(llvm::Value *BaseAddr, 1630 const VarDecl *V) { 1631 llvm::Value *Loc = Builder.CreateStructGEP(BaseAddr, 1, "forwarding"); 1632 Loc = Builder.CreateLoad(Loc); 1633 Loc = Builder.CreateStructGEP(Loc, getByRefValueLLVMField(V), 1634 V->getNameAsString()); 1635 return Loc; 1636 } 1637 1638 /// BuildByRefType - This routine changes a __block variable declared as T x 1639 /// into: 1640 /// 1641 /// struct { 1642 /// void *__isa; 1643 /// void *__forwarding; 1644 /// int32_t __flags; 1645 /// int32_t __size; 1646 /// void *__copy_helper; // only if needed 1647 /// void *__destroy_helper; // only if needed 1648 /// char padding[X]; // only if needed 1649 /// T x; 1650 /// } x 1651 /// 1652 llvm::Type *CodeGenFunction::BuildByRefType(const VarDecl *D) { 1653 std::pair<llvm::Type *, unsigned> &Info = ByRefValueInfo[D]; 1654 if (Info.first) 1655 return Info.first; 1656 1657 QualType Ty = D->getType(); 1658 1659 SmallVector<llvm::Type *, 8> types; 1660 1661 llvm::StructType *ByRefType = 1662 llvm::StructType::create(getLLVMContext(), 1663 "struct.__block_byref_" + D->getNameAsString()); 1664 1665 // void *__isa; 1666 types.push_back(Int8PtrTy); 1667 1668 // void *__forwarding; 1669 types.push_back(llvm::PointerType::getUnqual(ByRefType)); 1670 1671 // int32_t __flags; 1672 types.push_back(Int32Ty); 1673 1674 // int32_t __size; 1675 types.push_back(Int32Ty); 1676 1677 bool HasCopyAndDispose = getContext().BlockRequiresCopying(Ty); 1678 if (HasCopyAndDispose) { 1679 /// void *__copy_helper; 1680 types.push_back(Int8PtrTy); 1681 1682 /// void *__destroy_helper; 1683 types.push_back(Int8PtrTy); 1684 } 1685 1686 bool Packed = false; 1687 CharUnits Align = getContext().getDeclAlign(D); 1688 if (Align > getContext().toCharUnitsFromBits(Target.getPointerAlign(0))) { 1689 // We have to insert padding. 1690 1691 // The struct above has 2 32-bit integers. 1692 unsigned CurrentOffsetInBytes = 4 * 2; 1693 1694 // And either 2 or 4 pointers. 1695 CurrentOffsetInBytes += (HasCopyAndDispose ? 4 : 2) * 1696 CGM.getTargetData().getTypeAllocSize(Int8PtrTy); 1697 1698 // Align the offset. 1699 unsigned AlignedOffsetInBytes = 1700 llvm::RoundUpToAlignment(CurrentOffsetInBytes, Align.getQuantity()); 1701 1702 unsigned NumPaddingBytes = AlignedOffsetInBytes - CurrentOffsetInBytes; 1703 if (NumPaddingBytes > 0) { 1704 llvm::Type *Ty = llvm::Type::getInt8Ty(getLLVMContext()); 1705 // FIXME: We need a sema error for alignment larger than the minimum of 1706 // the maximal stack alignment and the alignment of malloc on the system. 1707 if (NumPaddingBytes > 1) 1708 Ty = llvm::ArrayType::get(Ty, NumPaddingBytes); 1709 1710 types.push_back(Ty); 1711 1712 // We want a packed struct. 1713 Packed = true; 1714 } 1715 } 1716 1717 // T x; 1718 types.push_back(ConvertTypeForMem(Ty)); 1719 1720 ByRefType->setBody(types, Packed); 1721 1722 Info.first = ByRefType; 1723 1724 Info.second = types.size() - 1; 1725 1726 return Info.first; 1727 } 1728 1729 /// Initialize the structural components of a __block variable, i.e. 1730 /// everything but the actual object. 1731 void CodeGenFunction::emitByrefStructureInit(const AutoVarEmission &emission) { 1732 // Find the address of the local. 1733 llvm::Value *addr = emission.Address; 1734 1735 // That's an alloca of the byref structure type. 1736 llvm::StructType *byrefType = cast<llvm::StructType>( 1737 cast<llvm::PointerType>(addr->getType())->getElementType()); 1738 1739 // Build the byref helpers if necessary. This is null if we don't need any. 1740 CodeGenModule::ByrefHelpers *helpers = 1741 buildByrefHelpers(*byrefType, emission); 1742 1743 const VarDecl &D = *emission.Variable; 1744 QualType type = D.getType(); 1745 1746 llvm::Value *V; 1747 1748 // Initialize the 'isa', which is just 0 or 1. 1749 int isa = 0; 1750 if (type.isObjCGCWeak()) 1751 isa = 1; 1752 V = Builder.CreateIntToPtr(Builder.getInt32(isa), Int8PtrTy, "isa"); 1753 Builder.CreateStore(V, Builder.CreateStructGEP(addr, 0, "byref.isa")); 1754 1755 // Store the address of the variable into its own forwarding pointer. 1756 Builder.CreateStore(addr, 1757 Builder.CreateStructGEP(addr, 1, "byref.forwarding")); 1758 1759 // Blocks ABI: 1760 // c) the flags field is set to either 0 if no helper functions are 1761 // needed or BLOCK_HAS_COPY_DISPOSE if they are, 1762 BlockFlags flags; 1763 if (helpers) flags |= BLOCK_HAS_COPY_DISPOSE; 1764 Builder.CreateStore(llvm::ConstantInt::get(IntTy, flags.getBitMask()), 1765 Builder.CreateStructGEP(addr, 2, "byref.flags")); 1766 1767 CharUnits byrefSize = CGM.GetTargetTypeStoreSize(byrefType); 1768 V = llvm::ConstantInt::get(IntTy, byrefSize.getQuantity()); 1769 Builder.CreateStore(V, Builder.CreateStructGEP(addr, 3, "byref.size")); 1770 1771 if (helpers) { 1772 llvm::Value *copy_helper = Builder.CreateStructGEP(addr, 4); 1773 Builder.CreateStore(helpers->CopyHelper, copy_helper); 1774 1775 llvm::Value *destroy_helper = Builder.CreateStructGEP(addr, 5); 1776 Builder.CreateStore(helpers->DisposeHelper, destroy_helper); 1777 } 1778 } 1779 1780 void CodeGenFunction::BuildBlockRelease(llvm::Value *V, BlockFieldFlags flags) { 1781 llvm::Value *F = CGM.getBlockObjectDispose(); 1782 llvm::Value *N; 1783 V = Builder.CreateBitCast(V, Int8PtrTy); 1784 N = llvm::ConstantInt::get(Int32Ty, flags.getBitMask()); 1785 Builder.CreateCall2(F, V, N); 1786 } 1787 1788 namespace { 1789 struct CallBlockRelease : EHScopeStack::Cleanup { 1790 llvm::Value *Addr; 1791 CallBlockRelease(llvm::Value *Addr) : Addr(Addr) {} 1792 1793 void Emit(CodeGenFunction &CGF, Flags flags) { 1794 // Should we be passing FIELD_IS_WEAK here? 1795 CGF.BuildBlockRelease(Addr, BLOCK_FIELD_IS_BYREF); 1796 } 1797 }; 1798 } 1799 1800 /// Enter a cleanup to destroy a __block variable. Note that this 1801 /// cleanup should be a no-op if the variable hasn't left the stack 1802 /// yet; if a cleanup is required for the variable itself, that needs 1803 /// to be done externally. 1804 void CodeGenFunction::enterByrefCleanup(const AutoVarEmission &emission) { 1805 // We don't enter this cleanup if we're in pure-GC mode. 1806 if (CGM.getLangOptions().getGC() == LangOptions::GCOnly) 1807 return; 1808 1809 EHStack.pushCleanup<CallBlockRelease>(NormalAndEHCleanup, emission.Address); 1810 } 1811 1812 /// Adjust the declaration of something from the blocks API. 1813 static void configureBlocksRuntimeObject(CodeGenModule &CGM, 1814 llvm::Constant *C) { 1815 if (!CGM.getLangOptions().BlocksRuntimeOptional) return; 1816 1817 llvm::GlobalValue *GV = cast<llvm::GlobalValue>(C->stripPointerCasts()); 1818 if (GV->isDeclaration() && 1819 GV->getLinkage() == llvm::GlobalValue::ExternalLinkage) 1820 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage); 1821 } 1822 1823 llvm::Constant *CodeGenModule::getBlockObjectDispose() { 1824 if (BlockObjectDispose) 1825 return BlockObjectDispose; 1826 1827 llvm::Type *args[] = { Int8PtrTy, Int32Ty }; 1828 llvm::FunctionType *fty 1829 = llvm::FunctionType::get(VoidTy, args, false); 1830 BlockObjectDispose = CreateRuntimeFunction(fty, "_Block_object_dispose"); 1831 configureBlocksRuntimeObject(*this, BlockObjectDispose); 1832 return BlockObjectDispose; 1833 } 1834 1835 llvm::Constant *CodeGenModule::getBlockObjectAssign() { 1836 if (BlockObjectAssign) 1837 return BlockObjectAssign; 1838 1839 llvm::Type *args[] = { Int8PtrTy, Int8PtrTy, Int32Ty }; 1840 llvm::FunctionType *fty 1841 = llvm::FunctionType::get(VoidTy, args, false); 1842 BlockObjectAssign = CreateRuntimeFunction(fty, "_Block_object_assign"); 1843 configureBlocksRuntimeObject(*this, BlockObjectAssign); 1844 return BlockObjectAssign; 1845 } 1846 1847 llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() { 1848 if (NSConcreteGlobalBlock) 1849 return NSConcreteGlobalBlock; 1850 1851 NSConcreteGlobalBlock = GetOrCreateLLVMGlobal("_NSConcreteGlobalBlock", 1852 Int8PtrTy->getPointerTo(), 0); 1853 configureBlocksRuntimeObject(*this, NSConcreteGlobalBlock); 1854 return NSConcreteGlobalBlock; 1855 } 1856 1857 llvm::Constant *CodeGenModule::getNSConcreteStackBlock() { 1858 if (NSConcreteStackBlock) 1859 return NSConcreteStackBlock; 1860 1861 NSConcreteStackBlock = GetOrCreateLLVMGlobal("_NSConcreteStackBlock", 1862 Int8PtrTy->getPointerTo(), 0); 1863 configureBlocksRuntimeObject(*this, NSConcreteStackBlock); 1864 return NSConcreteStackBlock; 1865 } 1866