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 BlockDecl *block, StringRef name) 29 : Name(name), CXXThisIndex(0), CanBeGlobal(false), NeedsCopyDispose(false), 30 HasCXXObject(false), UsesStret(false), StructureType(0), Block(block), 31 DominatingIP(0) { 32 33 // Skip asm prefix, if any. 'name' is usually taken directly from 34 // the mangled name of the enclosing function. 35 if (!name.empty() && name[0] == '\01') 36 name = name.substr(1); 37 } 38 39 // Anchor the vtable to this translation unit. 40 CodeGenModule::ByrefHelpers::~ByrefHelpers() {} 41 42 /// Build the given block as a global block. 43 static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM, 44 const CGBlockInfo &blockInfo, 45 llvm::Constant *blockFn); 46 47 /// Build the helper function to copy a block. 48 static llvm::Constant *buildCopyHelper(CodeGenModule &CGM, 49 const CGBlockInfo &blockInfo) { 50 return CodeGenFunction(CGM).GenerateCopyHelperFunction(blockInfo); 51 } 52 53 /// Build the helper function to dipose of a block. 54 static llvm::Constant *buildDisposeHelper(CodeGenModule &CGM, 55 const CGBlockInfo &blockInfo) { 56 return CodeGenFunction(CGM).GenerateDestroyHelperFunction(blockInfo); 57 } 58 59 /// Build the block descriptor constant for a block. 60 static llvm::Constant *buildBlockDescriptor(CodeGenModule &CGM, 61 const CGBlockInfo &blockInfo) { 62 ASTContext &C = CGM.getContext(); 63 64 llvm::Type *ulong = CGM.getTypes().ConvertType(C.UnsignedLongTy); 65 llvm::Type *i8p = CGM.getTypes().ConvertType(C.VoidPtrTy); 66 67 SmallVector<llvm::Constant*, 6> elements; 68 69 // reserved 70 elements.push_back(llvm::ConstantInt::get(ulong, 0)); 71 72 // Size 73 // FIXME: What is the right way to say this doesn't fit? We should give 74 // a user diagnostic in that case. Better fix would be to change the 75 // API to size_t. 76 elements.push_back(llvm::ConstantInt::get(ulong, 77 blockInfo.BlockSize.getQuantity())); 78 79 // Optional copy/dispose helpers. 80 if (blockInfo.NeedsCopyDispose) { 81 // copy_func_helper_decl 82 elements.push_back(buildCopyHelper(CGM, blockInfo)); 83 84 // destroy_func_decl 85 elements.push_back(buildDisposeHelper(CGM, blockInfo)); 86 } 87 88 // Signature. Mandatory ObjC-style method descriptor @encode sequence. 89 std::string typeAtEncoding = 90 CGM.getContext().getObjCEncodingForBlock(blockInfo.getBlockExpr()); 91 elements.push_back(llvm::ConstantExpr::getBitCast( 92 CGM.GetAddrOfConstantCString(typeAtEncoding), i8p)); 93 94 // GC layout. 95 if (C.getLangOpts().ObjC1) 96 elements.push_back(CGM.getObjCRuntime().BuildGCBlockLayout(CGM, blockInfo)); 97 else 98 elements.push_back(llvm::Constant::getNullValue(i8p)); 99 100 llvm::Constant *init = llvm::ConstantStruct::getAnon(elements); 101 102 llvm::GlobalVariable *global = 103 new llvm::GlobalVariable(CGM.getModule(), init->getType(), true, 104 llvm::GlobalValue::InternalLinkage, 105 init, "__block_descriptor_tmp"); 106 107 return llvm::ConstantExpr::getBitCast(global, CGM.getBlockDescriptorType()); 108 } 109 110 /* 111 Purely notional variadic template describing the layout of a block. 112 113 template <class _ResultType, class... _ParamTypes, class... _CaptureTypes> 114 struct Block_literal { 115 /// Initialized to one of: 116 /// extern void *_NSConcreteStackBlock[]; 117 /// extern void *_NSConcreteGlobalBlock[]; 118 /// 119 /// In theory, we could start one off malloc'ed by setting 120 /// BLOCK_NEEDS_FREE, giving it a refcount of 1, and using 121 /// this isa: 122 /// extern void *_NSConcreteMallocBlock[]; 123 struct objc_class *isa; 124 125 /// These are the flags (with corresponding bit number) that the 126 /// compiler is actually supposed to know about. 127 /// 25. BLOCK_HAS_COPY_DISPOSE - indicates that the block 128 /// descriptor provides copy and dispose helper functions 129 /// 26. BLOCK_HAS_CXX_OBJ - indicates that there's a captured 130 /// object with a nontrivial destructor or copy constructor 131 /// 28. BLOCK_IS_GLOBAL - indicates that the block is allocated 132 /// as global memory 133 /// 29. BLOCK_USE_STRET - indicates that the block function 134 /// uses stret, which objc_msgSend needs to know about 135 /// 30. BLOCK_HAS_SIGNATURE - indicates that the block has an 136 /// @encoded signature string 137 /// And we're not supposed to manipulate these: 138 /// 24. BLOCK_NEEDS_FREE - indicates that the block has been moved 139 /// to malloc'ed memory 140 /// 27. BLOCK_IS_GC - indicates that the block has been moved to 141 /// to GC-allocated memory 142 /// Additionally, the bottom 16 bits are a reference count which 143 /// should be zero on the stack. 144 int flags; 145 146 /// Reserved; should be zero-initialized. 147 int reserved; 148 149 /// Function pointer generated from block literal. 150 _ResultType (*invoke)(Block_literal *, _ParamTypes...); 151 152 /// Block description metadata generated from block literal. 153 struct Block_descriptor *block_descriptor; 154 155 /// Captured values follow. 156 _CapturesTypes captures...; 157 }; 158 */ 159 160 /// The number of fields in a block header. 161 const unsigned BlockHeaderSize = 5; 162 163 namespace { 164 /// A chunk of data that we actually have to capture in the block. 165 struct BlockLayoutChunk { 166 CharUnits Alignment; 167 CharUnits Size; 168 const BlockDecl::Capture *Capture; // null for 'this' 169 llvm::Type *Type; 170 171 BlockLayoutChunk(CharUnits align, CharUnits size, 172 const BlockDecl::Capture *capture, 173 llvm::Type *type) 174 : Alignment(align), Size(size), Capture(capture), Type(type) {} 175 176 /// Tell the block info that this chunk has the given field index. 177 void setIndex(CGBlockInfo &info, unsigned index) { 178 if (!Capture) 179 info.CXXThisIndex = index; 180 else 181 info.Captures[Capture->getVariable()] 182 = CGBlockInfo::Capture::makeIndex(index); 183 } 184 }; 185 186 /// Order by descending alignment. 187 bool operator<(const BlockLayoutChunk &left, const BlockLayoutChunk &right) { 188 return left.Alignment > right.Alignment; 189 } 190 } 191 192 /// Determines if the given type is safe for constant capture in C++. 193 static bool isSafeForCXXConstantCapture(QualType type) { 194 const RecordType *recordType = 195 type->getBaseElementTypeUnsafe()->getAs<RecordType>(); 196 197 // Only records can be unsafe. 198 if (!recordType) return true; 199 200 const CXXRecordDecl *record = cast<CXXRecordDecl>(recordType->getDecl()); 201 202 // Maintain semantics for classes with non-trivial dtors or copy ctors. 203 if (!record->hasTrivialDestructor()) return false; 204 if (!record->hasTrivialCopyConstructor()) return false; 205 206 // Otherwise, we just have to make sure there aren't any mutable 207 // fields that might have changed since initialization. 208 return !record->hasMutableFields(); 209 } 210 211 /// It is illegal to modify a const object after initialization. 212 /// Therefore, if a const object has a constant initializer, we don't 213 /// actually need to keep storage for it in the block; we'll just 214 /// rematerialize it at the start of the block function. This is 215 /// acceptable because we make no promises about address stability of 216 /// captured variables. 217 static llvm::Constant *tryCaptureAsConstant(CodeGenModule &CGM, 218 CodeGenFunction *CGF, 219 const VarDecl *var) { 220 QualType type = var->getType(); 221 222 // We can only do this if the variable is const. 223 if (!type.isConstQualified()) return 0; 224 225 // Furthermore, in C++ we have to worry about mutable fields: 226 // C++ [dcl.type.cv]p4: 227 // Except that any class member declared mutable can be 228 // modified, any attempt to modify a const object during its 229 // lifetime results in undefined behavior. 230 if (CGM.getLangOpts().CPlusPlus && !isSafeForCXXConstantCapture(type)) 231 return 0; 232 233 // If the variable doesn't have any initializer (shouldn't this be 234 // invalid?), it's not clear what we should do. Maybe capture as 235 // zero? 236 const Expr *init = var->getInit(); 237 if (!init) return 0; 238 239 return CGM.EmitConstantInit(*var, CGF); 240 } 241 242 /// Get the low bit of a nonzero character count. This is the 243 /// alignment of the nth byte if the 0th byte is universally aligned. 244 static CharUnits getLowBit(CharUnits v) { 245 return CharUnits::fromQuantity(v.getQuantity() & (~v.getQuantity() + 1)); 246 } 247 248 static void initializeForBlockHeader(CodeGenModule &CGM, CGBlockInfo &info, 249 SmallVectorImpl<llvm::Type*> &elementTypes) { 250 ASTContext &C = CGM.getContext(); 251 252 // The header is basically a 'struct { void *; int; int; void *; void *; }'. 253 CharUnits ptrSize, ptrAlign, intSize, intAlign; 254 llvm::tie(ptrSize, ptrAlign) = C.getTypeInfoInChars(C.VoidPtrTy); 255 llvm::tie(intSize, intAlign) = C.getTypeInfoInChars(C.IntTy); 256 257 // Are there crazy embedded platforms where this isn't true? 258 assert(intSize <= ptrSize && "layout assumptions horribly violated"); 259 260 CharUnits headerSize = ptrSize; 261 if (2 * intSize < ptrAlign) headerSize += ptrSize; 262 else headerSize += 2 * intSize; 263 headerSize += 2 * ptrSize; 264 265 info.BlockAlign = ptrAlign; 266 info.BlockSize = headerSize; 267 268 assert(elementTypes.empty()); 269 llvm::Type *i8p = CGM.getTypes().ConvertType(C.VoidPtrTy); 270 llvm::Type *intTy = CGM.getTypes().ConvertType(C.IntTy); 271 elementTypes.push_back(i8p); 272 elementTypes.push_back(intTy); 273 elementTypes.push_back(intTy); 274 elementTypes.push_back(i8p); 275 elementTypes.push_back(CGM.getBlockDescriptorType()); 276 277 assert(elementTypes.size() == BlockHeaderSize); 278 } 279 280 /// Compute the layout of the given block. Attempts to lay the block 281 /// out with minimal space requirements. 282 static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF, 283 CGBlockInfo &info) { 284 ASTContext &C = CGM.getContext(); 285 const BlockDecl *block = info.getBlockDecl(); 286 287 SmallVector<llvm::Type*, 8> elementTypes; 288 initializeForBlockHeader(CGM, info, elementTypes); 289 290 if (!block->hasCaptures()) { 291 info.StructureType = 292 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); 293 info.CanBeGlobal = true; 294 return; 295 } 296 297 // Collect the layout chunks. 298 SmallVector<BlockLayoutChunk, 16> layout; 299 layout.reserve(block->capturesCXXThis() + 300 (block->capture_end() - block->capture_begin())); 301 302 CharUnits maxFieldAlign; 303 304 // First, 'this'. 305 if (block->capturesCXXThis()) { 306 const DeclContext *DC = block->getDeclContext(); 307 for (; isa<BlockDecl>(DC); DC = cast<BlockDecl>(DC)->getDeclContext()) 308 ; 309 QualType thisType; 310 if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(DC)) 311 thisType = C.getPointerType(C.getRecordType(RD)); 312 else 313 thisType = cast<CXXMethodDecl>(DC)->getThisType(C); 314 315 llvm::Type *llvmType = CGM.getTypes().ConvertType(thisType); 316 std::pair<CharUnits,CharUnits> tinfo 317 = CGM.getContext().getTypeInfoInChars(thisType); 318 maxFieldAlign = std::max(maxFieldAlign, tinfo.second); 319 320 layout.push_back(BlockLayoutChunk(tinfo.second, tinfo.first, 0, llvmType)); 321 } 322 323 // Next, all the block captures. 324 for (BlockDecl::capture_const_iterator ci = block->capture_begin(), 325 ce = block->capture_end(); ci != ce; ++ci) { 326 const VarDecl *variable = ci->getVariable(); 327 328 if (ci->isByRef()) { 329 // We have to copy/dispose of the __block reference. 330 info.NeedsCopyDispose = true; 331 332 // Just use void* instead of a pointer to the byref type. 333 QualType byRefPtrTy = C.VoidPtrTy; 334 335 llvm::Type *llvmType = CGM.getTypes().ConvertType(byRefPtrTy); 336 std::pair<CharUnits,CharUnits> tinfo 337 = CGM.getContext().getTypeInfoInChars(byRefPtrTy); 338 maxFieldAlign = std::max(maxFieldAlign, tinfo.second); 339 340 layout.push_back(BlockLayoutChunk(tinfo.second, tinfo.first, 341 &*ci, llvmType)); 342 continue; 343 } 344 345 // Otherwise, build a layout chunk with the size and alignment of 346 // the declaration. 347 if (llvm::Constant *constant = tryCaptureAsConstant(CGM, CGF, variable)) { 348 info.Captures[variable] = CGBlockInfo::Capture::makeConstant(constant); 349 continue; 350 } 351 352 // If we have a lifetime qualifier, honor it for capture purposes. 353 // That includes *not* copying it if it's __unsafe_unretained. 354 if (Qualifiers::ObjCLifetime lifetime 355 = variable->getType().getObjCLifetime()) { 356 switch (lifetime) { 357 case Qualifiers::OCL_None: llvm_unreachable("impossible"); 358 case Qualifiers::OCL_ExplicitNone: 359 case Qualifiers::OCL_Autoreleasing: 360 break; 361 362 case Qualifiers::OCL_Strong: 363 case Qualifiers::OCL_Weak: 364 info.NeedsCopyDispose = true; 365 } 366 367 // Block pointers require copy/dispose. So do Objective-C pointers. 368 } else if (variable->getType()->isObjCRetainableType()) { 369 info.NeedsCopyDispose = true; 370 371 // So do types that require non-trivial copy construction. 372 } else if (ci->hasCopyExpr()) { 373 info.NeedsCopyDispose = true; 374 info.HasCXXObject = true; 375 376 // And so do types with destructors. 377 } else if (CGM.getLangOpts().CPlusPlus) { 378 if (const CXXRecordDecl *record = 379 variable->getType()->getAsCXXRecordDecl()) { 380 if (!record->hasTrivialDestructor()) { 381 info.HasCXXObject = true; 382 info.NeedsCopyDispose = true; 383 } 384 } 385 } 386 387 QualType VT = variable->getType(); 388 CharUnits size = C.getTypeSizeInChars(VT); 389 CharUnits align = C.getDeclAlign(variable); 390 391 maxFieldAlign = std::max(maxFieldAlign, align); 392 393 llvm::Type *llvmType = 394 CGM.getTypes().ConvertTypeForMem(VT); 395 396 layout.push_back(BlockLayoutChunk(align, size, &*ci, llvmType)); 397 } 398 399 // If that was everything, we're done here. 400 if (layout.empty()) { 401 info.StructureType = 402 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); 403 info.CanBeGlobal = true; 404 return; 405 } 406 407 // Sort the layout by alignment. We have to use a stable sort here 408 // to get reproducible results. There should probably be an 409 // llvm::array_pod_stable_sort. 410 std::stable_sort(layout.begin(), layout.end()); 411 412 CharUnits &blockSize = info.BlockSize; 413 info.BlockAlign = std::max(maxFieldAlign, info.BlockAlign); 414 415 // Assuming that the first byte in the header is maximally aligned, 416 // get the alignment of the first byte following the header. 417 CharUnits endAlign = getLowBit(blockSize); 418 419 // If the end of the header isn't satisfactorily aligned for the 420 // maximum thing, look for things that are okay with the header-end 421 // alignment, and keep appending them until we get something that's 422 // aligned right. This algorithm is only guaranteed optimal if 423 // that condition is satisfied at some point; otherwise we can get 424 // things like: 425 // header // next byte has alignment 4 426 // something_with_size_5; // next byte has alignment 1 427 // something_with_alignment_8; 428 // which has 7 bytes of padding, as opposed to the naive solution 429 // which might have less (?). 430 if (endAlign < maxFieldAlign) { 431 SmallVectorImpl<BlockLayoutChunk>::iterator 432 li = layout.begin() + 1, le = layout.end(); 433 434 // Look for something that the header end is already 435 // satisfactorily aligned for. 436 for (; li != le && endAlign < li->Alignment; ++li) 437 ; 438 439 // If we found something that's naturally aligned for the end of 440 // the header, keep adding things... 441 if (li != le) { 442 SmallVectorImpl<BlockLayoutChunk>::iterator first = li; 443 for (; li != le; ++li) { 444 assert(endAlign >= li->Alignment); 445 446 li->setIndex(info, elementTypes.size()); 447 elementTypes.push_back(li->Type); 448 blockSize += li->Size; 449 endAlign = getLowBit(blockSize); 450 451 // ...until we get to the alignment of the maximum field. 452 if (endAlign >= maxFieldAlign) 453 break; 454 } 455 456 // Don't re-append everything we just appended. 457 layout.erase(first, li); 458 } 459 } 460 461 // At this point, we just have to add padding if the end align still 462 // isn't aligned right. 463 if (endAlign < maxFieldAlign) { 464 CharUnits padding = maxFieldAlign - endAlign; 465 466 elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty, 467 padding.getQuantity())); 468 blockSize += padding; 469 470 endAlign = getLowBit(blockSize); 471 assert(endAlign >= maxFieldAlign); 472 } 473 474 // Slam everything else on now. This works because they have 475 // strictly decreasing alignment and we expect that size is always a 476 // multiple of alignment. 477 for (SmallVectorImpl<BlockLayoutChunk>::iterator 478 li = layout.begin(), le = layout.end(); li != le; ++li) { 479 assert(endAlign >= li->Alignment); 480 li->setIndex(info, elementTypes.size()); 481 elementTypes.push_back(li->Type); 482 blockSize += li->Size; 483 endAlign = getLowBit(blockSize); 484 } 485 486 info.StructureType = 487 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); 488 } 489 490 /// Enter the scope of a block. This should be run at the entrance to 491 /// a full-expression so that the block's cleanups are pushed at the 492 /// right place in the stack. 493 static void enterBlockScope(CodeGenFunction &CGF, BlockDecl *block) { 494 assert(CGF.HaveInsertPoint()); 495 496 // Allocate the block info and place it at the head of the list. 497 CGBlockInfo &blockInfo = 498 *new CGBlockInfo(block, CGF.CurFn->getName()); 499 blockInfo.NextBlockInfo = CGF.FirstBlockInfo; 500 CGF.FirstBlockInfo = &blockInfo; 501 502 // Compute information about the layout, etc., of this block, 503 // pushing cleanups as necessary. 504 computeBlockInfo(CGF.CGM, &CGF, blockInfo); 505 506 // Nothing else to do if it can be global. 507 if (blockInfo.CanBeGlobal) return; 508 509 // Make the allocation for the block. 510 blockInfo.Address = 511 CGF.CreateTempAlloca(blockInfo.StructureType, "block"); 512 blockInfo.Address->setAlignment(blockInfo.BlockAlign.getQuantity()); 513 514 // If there are cleanups to emit, enter them (but inactive). 515 if (!blockInfo.NeedsCopyDispose) return; 516 517 // Walk through the captures (in order) and find the ones not 518 // captured by constant. 519 for (BlockDecl::capture_const_iterator ci = block->capture_begin(), 520 ce = block->capture_end(); ci != ce; ++ci) { 521 // Ignore __block captures; there's nothing special in the 522 // on-stack block that we need to do for them. 523 if (ci->isByRef()) continue; 524 525 // Ignore variables that are constant-captured. 526 const VarDecl *variable = ci->getVariable(); 527 CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 528 if (capture.isConstant()) continue; 529 530 // Ignore objects that aren't destructed. 531 QualType::DestructionKind dtorKind = 532 variable->getType().isDestructedType(); 533 if (dtorKind == QualType::DK_none) continue; 534 535 CodeGenFunction::Destroyer *destroyer; 536 537 // Block captures count as local values and have imprecise semantics. 538 // They also can't be arrays, so need to worry about that. 539 if (dtorKind == QualType::DK_objc_strong_lifetime) { 540 destroyer = CodeGenFunction::destroyARCStrongImprecise; 541 } else { 542 destroyer = CGF.getDestroyer(dtorKind); 543 } 544 545 // GEP down to the address. 546 llvm::Value *addr = CGF.Builder.CreateStructGEP(blockInfo.Address, 547 capture.getIndex()); 548 549 // We can use that GEP as the dominating IP. 550 if (!blockInfo.DominatingIP) 551 blockInfo.DominatingIP = cast<llvm::Instruction>(addr); 552 553 CleanupKind cleanupKind = InactiveNormalCleanup; 554 bool useArrayEHCleanup = CGF.needsEHCleanup(dtorKind); 555 if (useArrayEHCleanup) 556 cleanupKind = InactiveNormalAndEHCleanup; 557 558 CGF.pushDestroy(cleanupKind, addr, variable->getType(), 559 destroyer, useArrayEHCleanup); 560 561 // Remember where that cleanup was. 562 capture.setCleanup(CGF.EHStack.stable_begin()); 563 } 564 } 565 566 /// Enter a full-expression with a non-trivial number of objects to 567 /// clean up. This is in this file because, at the moment, the only 568 /// kind of cleanup object is a BlockDecl*. 569 void CodeGenFunction::enterNonTrivialFullExpression(const ExprWithCleanups *E) { 570 assert(E->getNumObjects() != 0); 571 ArrayRef<ExprWithCleanups::CleanupObject> cleanups = E->getObjects(); 572 for (ArrayRef<ExprWithCleanups::CleanupObject>::iterator 573 i = cleanups.begin(), e = cleanups.end(); i != e; ++i) { 574 enterBlockScope(*this, *i); 575 } 576 } 577 578 /// Find the layout for the given block in a linked list and remove it. 579 static CGBlockInfo *findAndRemoveBlockInfo(CGBlockInfo **head, 580 const BlockDecl *block) { 581 while (true) { 582 assert(head && *head); 583 CGBlockInfo *cur = *head; 584 585 // If this is the block we're looking for, splice it out of the list. 586 if (cur->getBlockDecl() == block) { 587 *head = cur->NextBlockInfo; 588 return cur; 589 } 590 591 head = &cur->NextBlockInfo; 592 } 593 } 594 595 /// Destroy a chain of block layouts. 596 void CodeGenFunction::destroyBlockInfos(CGBlockInfo *head) { 597 assert(head && "destroying an empty chain"); 598 do { 599 CGBlockInfo *cur = head; 600 head = cur->NextBlockInfo; 601 delete cur; 602 } while (head != 0); 603 } 604 605 /// Emit a block literal expression in the current function. 606 llvm::Value *CodeGenFunction::EmitBlockLiteral(const BlockExpr *blockExpr) { 607 // If the block has no captures, we won't have a pre-computed 608 // layout for it. 609 if (!blockExpr->getBlockDecl()->hasCaptures()) { 610 CGBlockInfo blockInfo(blockExpr->getBlockDecl(), CurFn->getName()); 611 computeBlockInfo(CGM, this, blockInfo); 612 blockInfo.BlockExpression = blockExpr; 613 return EmitBlockLiteral(blockInfo); 614 } 615 616 // Find the block info for this block and take ownership of it. 617 OwningPtr<CGBlockInfo> blockInfo; 618 blockInfo.reset(findAndRemoveBlockInfo(&FirstBlockInfo, 619 blockExpr->getBlockDecl())); 620 621 blockInfo->BlockExpression = blockExpr; 622 return EmitBlockLiteral(*blockInfo); 623 } 624 625 llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo) { 626 // Using the computed layout, generate the actual block function. 627 bool isLambdaConv = blockInfo.getBlockDecl()->isConversionFromLambda(); 628 llvm::Constant *blockFn 629 = CodeGenFunction(CGM).GenerateBlockFunction(CurGD, blockInfo, 630 CurFuncDecl, LocalDeclMap, 631 isLambdaConv); 632 blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy); 633 634 // If there is nothing to capture, we can emit this as a global block. 635 if (blockInfo.CanBeGlobal) 636 return buildGlobalBlock(CGM, blockInfo, blockFn); 637 638 // Otherwise, we have to emit this as a local block. 639 640 llvm::Constant *isa = CGM.getNSConcreteStackBlock(); 641 isa = llvm::ConstantExpr::getBitCast(isa, VoidPtrTy); 642 643 // Build the block descriptor. 644 llvm::Constant *descriptor = buildBlockDescriptor(CGM, blockInfo); 645 646 llvm::AllocaInst *blockAddr = blockInfo.Address; 647 assert(blockAddr && "block has no address!"); 648 649 // Compute the initial on-stack block flags. 650 BlockFlags flags = BLOCK_HAS_SIGNATURE; 651 if (blockInfo.NeedsCopyDispose) flags |= BLOCK_HAS_COPY_DISPOSE; 652 if (blockInfo.HasCXXObject) flags |= BLOCK_HAS_CXX_OBJ; 653 if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET; 654 655 // Initialize the block literal. 656 Builder.CreateStore(isa, Builder.CreateStructGEP(blockAddr, 0, "block.isa")); 657 Builder.CreateStore(llvm::ConstantInt::get(IntTy, flags.getBitMask()), 658 Builder.CreateStructGEP(blockAddr, 1, "block.flags")); 659 Builder.CreateStore(llvm::ConstantInt::get(IntTy, 0), 660 Builder.CreateStructGEP(blockAddr, 2, "block.reserved")); 661 Builder.CreateStore(blockFn, Builder.CreateStructGEP(blockAddr, 3, 662 "block.invoke")); 663 Builder.CreateStore(descriptor, Builder.CreateStructGEP(blockAddr, 4, 664 "block.descriptor")); 665 666 // Finally, capture all the values into the block. 667 const BlockDecl *blockDecl = blockInfo.getBlockDecl(); 668 669 // First, 'this'. 670 if (blockDecl->capturesCXXThis()) { 671 llvm::Value *addr = Builder.CreateStructGEP(blockAddr, 672 blockInfo.CXXThisIndex, 673 "block.captured-this.addr"); 674 Builder.CreateStore(LoadCXXThis(), addr); 675 } 676 677 // Next, captured variables. 678 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(), 679 ce = blockDecl->capture_end(); ci != ce; ++ci) { 680 const VarDecl *variable = ci->getVariable(); 681 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 682 683 // Ignore constant captures. 684 if (capture.isConstant()) continue; 685 686 QualType type = variable->getType(); 687 688 // This will be a [[type]]*, except that a byref entry will just be 689 // an i8**. 690 llvm::Value *blockField = 691 Builder.CreateStructGEP(blockAddr, capture.getIndex(), 692 "block.captured"); 693 694 // Compute the address of the thing we're going to move into the 695 // block literal. 696 llvm::Value *src; 697 if (ci->isNested()) { 698 // We need to use the capture from the enclosing block. 699 const CGBlockInfo::Capture &enclosingCapture = 700 BlockInfo->getCapture(variable); 701 702 // This is a [[type]]*, except that a byref entry wil just be an i8**. 703 src = Builder.CreateStructGEP(LoadBlockStruct(), 704 enclosingCapture.getIndex(), 705 "block.capture.addr"); 706 } else if (blockDecl->isConversionFromLambda()) { 707 // The lambda capture in a lambda's conversion-to-block-pointer is 708 // special; we'll simply emit it directly. 709 src = 0; 710 } else { 711 // This is a [[type]]*. 712 src = LocalDeclMap[variable]; 713 } 714 715 // For byrefs, we just write the pointer to the byref struct into 716 // the block field. There's no need to chase the forwarding 717 // pointer at this point, since we're building something that will 718 // live a shorter life than the stack byref anyway. 719 if (ci->isByRef()) { 720 // Get a void* that points to the byref struct. 721 if (ci->isNested()) 722 src = Builder.CreateLoad(src, "byref.capture"); 723 else 724 src = Builder.CreateBitCast(src, VoidPtrTy); 725 726 // Write that void* into the capture field. 727 Builder.CreateStore(src, blockField); 728 729 // If we have a copy constructor, evaluate that into the block field. 730 } else if (const Expr *copyExpr = ci->getCopyExpr()) { 731 if (blockDecl->isConversionFromLambda()) { 732 // If we have a lambda conversion, emit the expression 733 // directly into the block instead. 734 CharUnits Align = getContext().getTypeAlignInChars(type); 735 AggValueSlot Slot = 736 AggValueSlot::forAddr(blockField, Align, Qualifiers(), 737 AggValueSlot::IsDestructed, 738 AggValueSlot::DoesNotNeedGCBarriers, 739 AggValueSlot::IsNotAliased); 740 EmitAggExpr(copyExpr, Slot); 741 } else { 742 EmitSynthesizedCXXCopyCtor(blockField, src, copyExpr); 743 } 744 745 // If it's a reference variable, copy the reference into the block field. 746 } else if (type->isReferenceType()) { 747 Builder.CreateStore(Builder.CreateLoad(src, "ref.val"), blockField); 748 749 // Otherwise, fake up a POD copy into the block field. 750 } else { 751 // Fake up a new variable so that EmitScalarInit doesn't think 752 // we're referring to the variable in its own initializer. 753 ImplicitParamDecl blockFieldPseudoVar(/*DC*/ 0, SourceLocation(), 754 /*name*/ 0, type); 755 756 // We use one of these or the other depending on whether the 757 // reference is nested. 758 DeclRefExpr declRef(const_cast<VarDecl*>(variable), 759 /*refersToEnclosing*/ ci->isNested(), type, 760 VK_LValue, SourceLocation()); 761 762 ImplicitCastExpr l2r(ImplicitCastExpr::OnStack, type, CK_LValueToRValue, 763 &declRef, VK_RValue); 764 EmitExprAsInit(&l2r, &blockFieldPseudoVar, 765 MakeAddrLValue(blockField, type, 766 getContext().getDeclAlign(variable)), 767 /*captured by init*/ false); 768 } 769 770 // Activate the cleanup if layout pushed one. 771 if (!ci->isByRef()) { 772 EHScopeStack::stable_iterator cleanup = capture.getCleanup(); 773 if (cleanup.isValid()) 774 ActivateCleanupBlock(cleanup, blockInfo.DominatingIP); 775 } 776 } 777 778 // Cast to the converted block-pointer type, which happens (somewhat 779 // unfortunately) to be a pointer to function type. 780 llvm::Value *result = 781 Builder.CreateBitCast(blockAddr, 782 ConvertType(blockInfo.getBlockExpr()->getType())); 783 784 return result; 785 } 786 787 788 llvm::Type *CodeGenModule::getBlockDescriptorType() { 789 if (BlockDescriptorType) 790 return BlockDescriptorType; 791 792 llvm::Type *UnsignedLongTy = 793 getTypes().ConvertType(getContext().UnsignedLongTy); 794 795 // struct __block_descriptor { 796 // unsigned long reserved; 797 // unsigned long block_size; 798 // 799 // // later, the following will be added 800 // 801 // struct { 802 // void (*copyHelper)(); 803 // void (*copyHelper)(); 804 // } helpers; // !!! optional 805 // 806 // const char *signature; // the block signature 807 // const char *layout; // reserved 808 // }; 809 BlockDescriptorType = 810 llvm::StructType::create("struct.__block_descriptor", 811 UnsignedLongTy, UnsignedLongTy, NULL); 812 813 // Now form a pointer to that. 814 BlockDescriptorType = llvm::PointerType::getUnqual(BlockDescriptorType); 815 return BlockDescriptorType; 816 } 817 818 llvm::Type *CodeGenModule::getGenericBlockLiteralType() { 819 if (GenericBlockLiteralType) 820 return GenericBlockLiteralType; 821 822 llvm::Type *BlockDescPtrTy = getBlockDescriptorType(); 823 824 // struct __block_literal_generic { 825 // void *__isa; 826 // int __flags; 827 // int __reserved; 828 // void (*__invoke)(void *); 829 // struct __block_descriptor *__descriptor; 830 // }; 831 GenericBlockLiteralType = 832 llvm::StructType::create("struct.__block_literal_generic", 833 VoidPtrTy, IntTy, IntTy, VoidPtrTy, 834 BlockDescPtrTy, NULL); 835 836 return GenericBlockLiteralType; 837 } 838 839 840 RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr* E, 841 ReturnValueSlot ReturnValue) { 842 const BlockPointerType *BPT = 843 E->getCallee()->getType()->getAs<BlockPointerType>(); 844 845 llvm::Value *Callee = EmitScalarExpr(E->getCallee()); 846 847 // Get a pointer to the generic block literal. 848 llvm::Type *BlockLiteralTy = 849 llvm::PointerType::getUnqual(CGM.getGenericBlockLiteralType()); 850 851 // Bitcast the callee to a block literal. 852 llvm::Value *BlockLiteral = 853 Builder.CreateBitCast(Callee, BlockLiteralTy, "block.literal"); 854 855 // Get the function pointer from the literal. 856 llvm::Value *FuncPtr = Builder.CreateStructGEP(BlockLiteral, 3); 857 858 BlockLiteral = Builder.CreateBitCast(BlockLiteral, VoidPtrTy); 859 860 // Add the block literal. 861 CallArgList Args; 862 Args.add(RValue::get(BlockLiteral), getContext().VoidPtrTy); 863 864 QualType FnType = BPT->getPointeeType(); 865 866 // And the rest of the arguments. 867 EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(), 868 E->arg_begin(), E->arg_end()); 869 870 // Load the function. 871 llvm::Value *Func = Builder.CreateLoad(FuncPtr); 872 873 const FunctionType *FuncTy = FnType->castAs<FunctionType>(); 874 const CGFunctionInfo &FnInfo = 875 CGM.getTypes().arrangeFunctionCall(Args, FuncTy); 876 877 // Cast the function pointer to the right type. 878 llvm::Type *BlockFTy = CGM.getTypes().GetFunctionType(FnInfo); 879 880 llvm::Type *BlockFTyPtr = llvm::PointerType::getUnqual(BlockFTy); 881 Func = Builder.CreateBitCast(Func, BlockFTyPtr); 882 883 // And call the block. 884 return EmitCall(FnInfo, Func, ReturnValue, Args); 885 } 886 887 llvm::Value *CodeGenFunction::GetAddrOfBlockDecl(const VarDecl *variable, 888 bool isByRef) { 889 assert(BlockInfo && "evaluating block ref without block information?"); 890 const CGBlockInfo::Capture &capture = BlockInfo->getCapture(variable); 891 892 // Handle constant captures. 893 if (capture.isConstant()) return LocalDeclMap[variable]; 894 895 llvm::Value *addr = 896 Builder.CreateStructGEP(LoadBlockStruct(), capture.getIndex(), 897 "block.capture.addr"); 898 899 if (isByRef) { 900 // addr should be a void** right now. Load, then cast the result 901 // to byref*. 902 903 addr = Builder.CreateLoad(addr); 904 llvm::PointerType *byrefPointerType 905 = llvm::PointerType::get(BuildByRefType(variable), 0); 906 addr = Builder.CreateBitCast(addr, byrefPointerType, 907 "byref.addr"); 908 909 // Follow the forwarding pointer. 910 addr = Builder.CreateStructGEP(addr, 1, "byref.forwarding"); 911 addr = Builder.CreateLoad(addr, "byref.addr.forwarded"); 912 913 // Cast back to byref* and GEP over to the actual object. 914 addr = Builder.CreateBitCast(addr, byrefPointerType); 915 addr = Builder.CreateStructGEP(addr, getByRefValueLLVMField(variable), 916 variable->getNameAsString()); 917 } 918 919 if (variable->getType()->isReferenceType()) 920 addr = Builder.CreateLoad(addr, "ref.tmp"); 921 922 return addr; 923 } 924 925 llvm::Constant * 926 CodeGenModule::GetAddrOfGlobalBlock(const BlockExpr *blockExpr, 927 const char *name) { 928 CGBlockInfo blockInfo(blockExpr->getBlockDecl(), name); 929 blockInfo.BlockExpression = blockExpr; 930 931 // Compute information about the layout, etc., of this block. 932 computeBlockInfo(*this, 0, blockInfo); 933 934 // Using that metadata, generate the actual block function. 935 llvm::Constant *blockFn; 936 { 937 llvm::DenseMap<const Decl*, llvm::Value*> LocalDeclMap; 938 blockFn = CodeGenFunction(*this).GenerateBlockFunction(GlobalDecl(), 939 blockInfo, 940 0, LocalDeclMap, 941 false); 942 } 943 blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy); 944 945 return buildGlobalBlock(*this, blockInfo, blockFn); 946 } 947 948 static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM, 949 const CGBlockInfo &blockInfo, 950 llvm::Constant *blockFn) { 951 assert(blockInfo.CanBeGlobal); 952 953 // Generate the constants for the block literal initializer. 954 llvm::Constant *fields[BlockHeaderSize]; 955 956 // isa 957 fields[0] = CGM.getNSConcreteGlobalBlock(); 958 959 // __flags 960 BlockFlags flags = BLOCK_IS_GLOBAL | BLOCK_HAS_SIGNATURE; 961 if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET; 962 963 fields[1] = llvm::ConstantInt::get(CGM.IntTy, flags.getBitMask()); 964 965 // Reserved 966 fields[2] = llvm::Constant::getNullValue(CGM.IntTy); 967 968 // Function 969 fields[3] = blockFn; 970 971 // Descriptor 972 fields[4] = buildBlockDescriptor(CGM, blockInfo); 973 974 llvm::Constant *init = llvm::ConstantStruct::getAnon(fields); 975 976 llvm::GlobalVariable *literal = 977 new llvm::GlobalVariable(CGM.getModule(), 978 init->getType(), 979 /*constant*/ true, 980 llvm::GlobalVariable::InternalLinkage, 981 init, 982 "__block_literal_global"); 983 literal->setAlignment(blockInfo.BlockAlign.getQuantity()); 984 985 // Return a constant of the appropriately-casted type. 986 llvm::Type *requiredType = 987 CGM.getTypes().ConvertType(blockInfo.getBlockExpr()->getType()); 988 return llvm::ConstantExpr::getBitCast(literal, requiredType); 989 } 990 991 llvm::Function * 992 CodeGenFunction::GenerateBlockFunction(GlobalDecl GD, 993 const CGBlockInfo &blockInfo, 994 const Decl *outerFnDecl, 995 const DeclMapTy &ldm, 996 bool IsLambdaConversionToBlock) { 997 const BlockDecl *blockDecl = blockInfo.getBlockDecl(); 998 999 // Check if we should generate debug info for this block function. 1000 if (CGM.getModuleDebugInfo()) 1001 DebugInfo = CGM.getModuleDebugInfo(); 1002 1003 BlockInfo = &blockInfo; 1004 1005 // Arrange for local static and local extern declarations to appear 1006 // to be local to this function as well, in case they're directly 1007 // referenced in a block. 1008 for (DeclMapTy::const_iterator i = ldm.begin(), e = ldm.end(); i != e; ++i) { 1009 const VarDecl *var = dyn_cast<VarDecl>(i->first); 1010 if (var && !var->hasLocalStorage()) 1011 LocalDeclMap[var] = i->second; 1012 } 1013 1014 // Begin building the function declaration. 1015 1016 // Build the argument list. 1017 FunctionArgList args; 1018 1019 // The first argument is the block pointer. Just take it as a void* 1020 // and cast it later. 1021 QualType selfTy = getContext().VoidPtrTy; 1022 IdentifierInfo *II = &CGM.getContext().Idents.get(".block_descriptor"); 1023 1024 ImplicitParamDecl selfDecl(const_cast<BlockDecl*>(blockDecl), 1025 SourceLocation(), II, selfTy); 1026 args.push_back(&selfDecl); 1027 1028 // Now add the rest of the parameters. 1029 for (BlockDecl::param_const_iterator i = blockDecl->param_begin(), 1030 e = blockDecl->param_end(); i != e; ++i) 1031 args.push_back(*i); 1032 1033 // Create the function declaration. 1034 const FunctionProtoType *fnType = blockInfo.getBlockExpr()->getFunctionType(); 1035 const CGFunctionInfo &fnInfo = 1036 CGM.getTypes().arrangeFunctionDeclaration(fnType->getResultType(), args, 1037 fnType->getExtInfo(), 1038 fnType->isVariadic()); 1039 if (CGM.ReturnTypeUsesSRet(fnInfo)) 1040 blockInfo.UsesStret = true; 1041 1042 llvm::FunctionType *fnLLVMType = CGM.getTypes().GetFunctionType(fnInfo); 1043 1044 MangleBuffer name; 1045 CGM.getBlockMangledName(GD, name, blockDecl); 1046 llvm::Function *fn = 1047 llvm::Function::Create(fnLLVMType, llvm::GlobalValue::InternalLinkage, 1048 name.getString(), &CGM.getModule()); 1049 CGM.SetInternalFunctionAttributes(blockDecl, fn, fnInfo); 1050 1051 // Begin generating the function. 1052 StartFunction(blockDecl, fnType->getResultType(), fn, fnInfo, args, 1053 blockInfo.getBlockExpr()->getBody()->getLocStart()); 1054 CurFuncDecl = outerFnDecl; // StartFunction sets this to blockDecl 1055 1056 // Okay. Undo some of what StartFunction did. 1057 1058 // Pull the 'self' reference out of the local decl map. 1059 llvm::Value *blockAddr = LocalDeclMap[&selfDecl]; 1060 LocalDeclMap.erase(&selfDecl); 1061 BlockPointer = Builder.CreateBitCast(blockAddr, 1062 blockInfo.StructureType->getPointerTo(), 1063 "block"); 1064 1065 // If we have a C++ 'this' reference, go ahead and force it into 1066 // existence now. 1067 if (blockDecl->capturesCXXThis()) { 1068 llvm::Value *addr = Builder.CreateStructGEP(BlockPointer, 1069 blockInfo.CXXThisIndex, 1070 "block.captured-this"); 1071 CXXThisValue = Builder.CreateLoad(addr, "this"); 1072 } 1073 1074 // LoadObjCSelf() expects there to be an entry for 'self' in LocalDeclMap; 1075 // appease it. 1076 if (const ObjCMethodDecl *method 1077 = dyn_cast_or_null<ObjCMethodDecl>(CurFuncDecl)) { 1078 const VarDecl *self = method->getSelfDecl(); 1079 1080 // There might not be a capture for 'self', but if there is... 1081 if (blockInfo.Captures.count(self)) { 1082 const CGBlockInfo::Capture &capture = blockInfo.getCapture(self); 1083 llvm::Value *selfAddr = Builder.CreateStructGEP(BlockPointer, 1084 capture.getIndex(), 1085 "block.captured-self"); 1086 LocalDeclMap[self] = selfAddr; 1087 } 1088 } 1089 1090 // Also force all the constant captures. 1091 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(), 1092 ce = blockDecl->capture_end(); ci != ce; ++ci) { 1093 const VarDecl *variable = ci->getVariable(); 1094 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 1095 if (!capture.isConstant()) continue; 1096 1097 unsigned align = getContext().getDeclAlign(variable).getQuantity(); 1098 1099 llvm::AllocaInst *alloca = 1100 CreateMemTemp(variable->getType(), "block.captured-const"); 1101 alloca->setAlignment(align); 1102 1103 Builder.CreateStore(capture.getConstant(), alloca, align); 1104 1105 LocalDeclMap[variable] = alloca; 1106 } 1107 1108 // Save a spot to insert the debug information for all the DeclRefExprs. 1109 llvm::BasicBlock *entry = Builder.GetInsertBlock(); 1110 llvm::BasicBlock::iterator entry_ptr = Builder.GetInsertPoint(); 1111 --entry_ptr; 1112 1113 if (IsLambdaConversionToBlock) 1114 EmitLambdaBlockInvokeBody(); 1115 else 1116 EmitStmt(blockDecl->getBody()); 1117 1118 // Remember where we were... 1119 llvm::BasicBlock *resume = Builder.GetInsertBlock(); 1120 1121 // Go back to the entry. 1122 ++entry_ptr; 1123 Builder.SetInsertPoint(entry, entry_ptr); 1124 1125 // Emit debug information for all the DeclRefExprs. 1126 // FIXME: also for 'this' 1127 if (CGDebugInfo *DI = getDebugInfo()) { 1128 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(), 1129 ce = blockDecl->capture_end(); ci != ce; ++ci) { 1130 const VarDecl *variable = ci->getVariable(); 1131 DI->EmitLocation(Builder, variable->getLocation()); 1132 1133 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 1134 if (capture.isConstant()) { 1135 DI->EmitDeclareOfAutoVariable(variable, LocalDeclMap[variable], 1136 Builder); 1137 continue; 1138 } 1139 1140 DI->EmitDeclareOfBlockDeclRefVariable(variable, BlockPointer, 1141 Builder, blockInfo); 1142 } 1143 } 1144 1145 // And resume where we left off. 1146 if (resume == 0) 1147 Builder.ClearInsertionPoint(); 1148 else 1149 Builder.SetInsertPoint(resume); 1150 1151 FinishFunction(cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc()); 1152 1153 return fn; 1154 } 1155 1156 /* 1157 notes.push_back(HelperInfo()); 1158 HelperInfo ¬e = notes.back(); 1159 note.index = capture.getIndex(); 1160 note.RequiresCopying = (ci->hasCopyExpr() || BlockRequiresCopying(type)); 1161 note.cxxbar_import = ci->getCopyExpr(); 1162 1163 if (ci->isByRef()) { 1164 note.flag = BLOCK_FIELD_IS_BYREF; 1165 if (type.isObjCGCWeak()) 1166 note.flag |= BLOCK_FIELD_IS_WEAK; 1167 } else if (type->isBlockPointerType()) { 1168 note.flag = BLOCK_FIELD_IS_BLOCK; 1169 } else { 1170 note.flag = BLOCK_FIELD_IS_OBJECT; 1171 } 1172 */ 1173 1174 1175 1176 llvm::Constant * 1177 CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) { 1178 ASTContext &C = getContext(); 1179 1180 FunctionArgList args; 1181 ImplicitParamDecl dstDecl(0, SourceLocation(), 0, C.VoidPtrTy); 1182 args.push_back(&dstDecl); 1183 ImplicitParamDecl srcDecl(0, SourceLocation(), 0, C.VoidPtrTy); 1184 args.push_back(&srcDecl); 1185 1186 const CGFunctionInfo &FI = 1187 CGM.getTypes().arrangeFunctionDeclaration(C.VoidTy, args, 1188 FunctionType::ExtInfo(), 1189 /*variadic*/ false); 1190 1191 // FIXME: it would be nice if these were mergeable with things with 1192 // identical semantics. 1193 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI); 1194 1195 llvm::Function *Fn = 1196 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, 1197 "__copy_helper_block_", &CGM.getModule()); 1198 1199 IdentifierInfo *II 1200 = &CGM.getContext().Idents.get("__copy_helper_block_"); 1201 1202 // Check if we should generate debug info for this block helper function. 1203 if (CGM.getModuleDebugInfo()) 1204 DebugInfo = CGM.getModuleDebugInfo(); 1205 1206 FunctionDecl *FD = FunctionDecl::Create(C, 1207 C.getTranslationUnitDecl(), 1208 SourceLocation(), 1209 SourceLocation(), II, C.VoidTy, 0, 1210 SC_Static, 1211 SC_None, 1212 false, 1213 false); 1214 StartFunction(FD, C.VoidTy, Fn, FI, args, SourceLocation()); 1215 1216 llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo(); 1217 1218 llvm::Value *src = GetAddrOfLocalVar(&srcDecl); 1219 src = Builder.CreateLoad(src); 1220 src = Builder.CreateBitCast(src, structPtrTy, "block.source"); 1221 1222 llvm::Value *dst = GetAddrOfLocalVar(&dstDecl); 1223 dst = Builder.CreateLoad(dst); 1224 dst = Builder.CreateBitCast(dst, structPtrTy, "block.dest"); 1225 1226 const BlockDecl *blockDecl = blockInfo.getBlockDecl(); 1227 1228 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(), 1229 ce = blockDecl->capture_end(); ci != ce; ++ci) { 1230 const VarDecl *variable = ci->getVariable(); 1231 QualType type = variable->getType(); 1232 1233 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 1234 if (capture.isConstant()) continue; 1235 1236 const Expr *copyExpr = ci->getCopyExpr(); 1237 BlockFieldFlags flags; 1238 1239 bool isARCWeakCapture = false; 1240 1241 if (copyExpr) { 1242 assert(!ci->isByRef()); 1243 // don't bother computing flags 1244 1245 } else if (ci->isByRef()) { 1246 flags = BLOCK_FIELD_IS_BYREF; 1247 if (type.isObjCGCWeak()) 1248 flags |= BLOCK_FIELD_IS_WEAK; 1249 1250 } else if (type->isObjCRetainableType()) { 1251 flags = BLOCK_FIELD_IS_OBJECT; 1252 if (type->isBlockPointerType()) 1253 flags = BLOCK_FIELD_IS_BLOCK; 1254 1255 // Special rules for ARC captures: 1256 if (getLangOpts().ObjCAutoRefCount) { 1257 Qualifiers qs = type.getQualifiers(); 1258 1259 // Don't generate special copy logic for a captured object 1260 // unless it's __strong or __weak. 1261 if (!qs.hasStrongOrWeakObjCLifetime()) 1262 continue; 1263 1264 // Support __weak direct captures. 1265 if (qs.getObjCLifetime() == Qualifiers::OCL_Weak) 1266 isARCWeakCapture = true; 1267 } 1268 } else { 1269 continue; 1270 } 1271 1272 unsigned index = capture.getIndex(); 1273 llvm::Value *srcField = Builder.CreateStructGEP(src, index); 1274 llvm::Value *dstField = Builder.CreateStructGEP(dst, index); 1275 1276 // If there's an explicit copy expression, we do that. 1277 if (copyExpr) { 1278 EmitSynthesizedCXXCopyCtor(dstField, srcField, copyExpr); 1279 } else if (isARCWeakCapture) { 1280 EmitARCCopyWeak(dstField, srcField); 1281 } else { 1282 llvm::Value *srcValue = Builder.CreateLoad(srcField, "blockcopy.src"); 1283 srcValue = Builder.CreateBitCast(srcValue, VoidPtrTy); 1284 llvm::Value *dstAddr = Builder.CreateBitCast(dstField, VoidPtrTy); 1285 Builder.CreateCall3(CGM.getBlockObjectAssign(), dstAddr, srcValue, 1286 llvm::ConstantInt::get(Int32Ty, flags.getBitMask())); 1287 } 1288 } 1289 1290 FinishFunction(); 1291 1292 return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy); 1293 } 1294 1295 llvm::Constant * 1296 CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) { 1297 ASTContext &C = getContext(); 1298 1299 FunctionArgList args; 1300 ImplicitParamDecl srcDecl(0, SourceLocation(), 0, C.VoidPtrTy); 1301 args.push_back(&srcDecl); 1302 1303 const CGFunctionInfo &FI = 1304 CGM.getTypes().arrangeFunctionDeclaration(C.VoidTy, args, 1305 FunctionType::ExtInfo(), 1306 /*variadic*/ false); 1307 1308 // FIXME: We'd like to put these into a mergable by content, with 1309 // internal linkage. 1310 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI); 1311 1312 llvm::Function *Fn = 1313 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, 1314 "__destroy_helper_block_", &CGM.getModule()); 1315 1316 // Check if we should generate debug info for this block destroy function. 1317 if (CGM.getModuleDebugInfo()) 1318 DebugInfo = CGM.getModuleDebugInfo(); 1319 1320 IdentifierInfo *II 1321 = &CGM.getContext().Idents.get("__destroy_helper_block_"); 1322 1323 FunctionDecl *FD = FunctionDecl::Create(C, C.getTranslationUnitDecl(), 1324 SourceLocation(), 1325 SourceLocation(), II, C.VoidTy, 0, 1326 SC_Static, 1327 SC_None, 1328 false, false); 1329 StartFunction(FD, C.VoidTy, Fn, FI, args, SourceLocation()); 1330 1331 llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo(); 1332 1333 llvm::Value *src = GetAddrOfLocalVar(&srcDecl); 1334 src = Builder.CreateLoad(src); 1335 src = Builder.CreateBitCast(src, structPtrTy, "block"); 1336 1337 const BlockDecl *blockDecl = blockInfo.getBlockDecl(); 1338 1339 CodeGenFunction::RunCleanupsScope cleanups(*this); 1340 1341 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(), 1342 ce = blockDecl->capture_end(); ci != ce; ++ci) { 1343 const VarDecl *variable = ci->getVariable(); 1344 QualType type = variable->getType(); 1345 1346 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); 1347 if (capture.isConstant()) continue; 1348 1349 BlockFieldFlags flags; 1350 const CXXDestructorDecl *dtor = 0; 1351 1352 bool isARCWeakCapture = false; 1353 1354 if (ci->isByRef()) { 1355 flags = BLOCK_FIELD_IS_BYREF; 1356 if (type.isObjCGCWeak()) 1357 flags |= BLOCK_FIELD_IS_WEAK; 1358 } else if (const CXXRecordDecl *record = type->getAsCXXRecordDecl()) { 1359 if (record->hasTrivialDestructor()) 1360 continue; 1361 dtor = record->getDestructor(); 1362 } else if (type->isObjCRetainableType()) { 1363 flags = BLOCK_FIELD_IS_OBJECT; 1364 if (type->isBlockPointerType()) 1365 flags = BLOCK_FIELD_IS_BLOCK; 1366 1367 // Special rules for ARC captures. 1368 if (getLangOpts().ObjCAutoRefCount) { 1369 Qualifiers qs = type.getQualifiers(); 1370 1371 // Don't generate special dispose logic for a captured object 1372 // unless it's __strong or __weak. 1373 if (!qs.hasStrongOrWeakObjCLifetime()) 1374 continue; 1375 1376 // Support __weak direct captures. 1377 if (qs.getObjCLifetime() == Qualifiers::OCL_Weak) 1378 isARCWeakCapture = true; 1379 } 1380 } else { 1381 continue; 1382 } 1383 1384 unsigned index = capture.getIndex(); 1385 llvm::Value *srcField = Builder.CreateStructGEP(src, index); 1386 1387 // If there's an explicit copy expression, we do that. 1388 if (dtor) { 1389 PushDestructorCleanup(dtor, srcField); 1390 1391 // If this is a __weak capture, emit the release directly. 1392 } else if (isARCWeakCapture) { 1393 EmitARCDestroyWeak(srcField); 1394 1395 // Otherwise we call _Block_object_dispose. It wouldn't be too 1396 // hard to just emit this as a cleanup if we wanted to make sure 1397 // that things were done in reverse. 1398 } else { 1399 llvm::Value *value = Builder.CreateLoad(srcField); 1400 value = Builder.CreateBitCast(value, VoidPtrTy); 1401 BuildBlockRelease(value, flags); 1402 } 1403 } 1404 1405 cleanups.ForceCleanup(); 1406 1407 FinishFunction(); 1408 1409 return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy); 1410 } 1411 1412 namespace { 1413 1414 /// Emits the copy/dispose helper functions for a __block object of id type. 1415 class ObjectByrefHelpers : public CodeGenModule::ByrefHelpers { 1416 BlockFieldFlags Flags; 1417 1418 public: 1419 ObjectByrefHelpers(CharUnits alignment, BlockFieldFlags flags) 1420 : ByrefHelpers(alignment), Flags(flags) {} 1421 1422 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1423 llvm::Value *srcField) { 1424 destField = CGF.Builder.CreateBitCast(destField, CGF.VoidPtrTy); 1425 1426 srcField = CGF.Builder.CreateBitCast(srcField, CGF.VoidPtrPtrTy); 1427 llvm::Value *srcValue = CGF.Builder.CreateLoad(srcField); 1428 1429 unsigned flags = (Flags | BLOCK_BYREF_CALLER).getBitMask(); 1430 1431 llvm::Value *flagsVal = llvm::ConstantInt::get(CGF.Int32Ty, flags); 1432 llvm::Value *fn = CGF.CGM.getBlockObjectAssign(); 1433 CGF.Builder.CreateCall3(fn, destField, srcValue, flagsVal); 1434 } 1435 1436 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) { 1437 field = CGF.Builder.CreateBitCast(field, CGF.Int8PtrTy->getPointerTo(0)); 1438 llvm::Value *value = CGF.Builder.CreateLoad(field); 1439 1440 CGF.BuildBlockRelease(value, Flags | BLOCK_BYREF_CALLER); 1441 } 1442 1443 void profileImpl(llvm::FoldingSetNodeID &id) const { 1444 id.AddInteger(Flags.getBitMask()); 1445 } 1446 }; 1447 1448 /// Emits the copy/dispose helpers for an ARC __block __weak variable. 1449 class ARCWeakByrefHelpers : public CodeGenModule::ByrefHelpers { 1450 public: 1451 ARCWeakByrefHelpers(CharUnits alignment) : ByrefHelpers(alignment) {} 1452 1453 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1454 llvm::Value *srcField) { 1455 CGF.EmitARCMoveWeak(destField, srcField); 1456 } 1457 1458 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) { 1459 CGF.EmitARCDestroyWeak(field); 1460 } 1461 1462 void profileImpl(llvm::FoldingSetNodeID &id) const { 1463 // 0 is distinguishable from all pointers and byref flags 1464 id.AddInteger(0); 1465 } 1466 }; 1467 1468 /// Emits the copy/dispose helpers for an ARC __block __strong variable 1469 /// that's not of block-pointer type. 1470 class ARCStrongByrefHelpers : public CodeGenModule::ByrefHelpers { 1471 public: 1472 ARCStrongByrefHelpers(CharUnits alignment) : ByrefHelpers(alignment) {} 1473 1474 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1475 llvm::Value *srcField) { 1476 // Do a "move" by copying the value and then zeroing out the old 1477 // variable. 1478 1479 llvm::LoadInst *value = CGF.Builder.CreateLoad(srcField); 1480 value->setAlignment(Alignment.getQuantity()); 1481 1482 llvm::Value *null = 1483 llvm::ConstantPointerNull::get(cast<llvm::PointerType>(value->getType())); 1484 1485 llvm::StoreInst *store = CGF.Builder.CreateStore(value, destField); 1486 store->setAlignment(Alignment.getQuantity()); 1487 1488 store = CGF.Builder.CreateStore(null, srcField); 1489 store->setAlignment(Alignment.getQuantity()); 1490 } 1491 1492 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) { 1493 llvm::LoadInst *value = CGF.Builder.CreateLoad(field); 1494 value->setAlignment(Alignment.getQuantity()); 1495 1496 CGF.EmitARCRelease(value, /*precise*/ false); 1497 } 1498 1499 void profileImpl(llvm::FoldingSetNodeID &id) const { 1500 // 1 is distinguishable from all pointers and byref flags 1501 id.AddInteger(1); 1502 } 1503 }; 1504 1505 /// Emits the copy/dispose helpers for an ARC __block __strong 1506 /// variable that's of block-pointer type. 1507 class ARCStrongBlockByrefHelpers : public CodeGenModule::ByrefHelpers { 1508 public: 1509 ARCStrongBlockByrefHelpers(CharUnits alignment) : ByrefHelpers(alignment) {} 1510 1511 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1512 llvm::Value *srcField) { 1513 // Do the copy with objc_retainBlock; that's all that 1514 // _Block_object_assign would do anyway, and we'd have to pass the 1515 // right arguments to make sure it doesn't get no-op'ed. 1516 llvm::LoadInst *oldValue = CGF.Builder.CreateLoad(srcField); 1517 oldValue->setAlignment(Alignment.getQuantity()); 1518 1519 llvm::Value *copy = CGF.EmitARCRetainBlock(oldValue, /*mandatory*/ true); 1520 1521 llvm::StoreInst *store = CGF.Builder.CreateStore(copy, destField); 1522 store->setAlignment(Alignment.getQuantity()); 1523 } 1524 1525 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) { 1526 llvm::LoadInst *value = CGF.Builder.CreateLoad(field); 1527 value->setAlignment(Alignment.getQuantity()); 1528 1529 CGF.EmitARCRelease(value, /*precise*/ false); 1530 } 1531 1532 void profileImpl(llvm::FoldingSetNodeID &id) const { 1533 // 2 is distinguishable from all pointers and byref flags 1534 id.AddInteger(2); 1535 } 1536 }; 1537 1538 /// Emits the copy/dispose helpers for a __block variable with a 1539 /// nontrivial copy constructor or destructor. 1540 class CXXByrefHelpers : public CodeGenModule::ByrefHelpers { 1541 QualType VarType; 1542 const Expr *CopyExpr; 1543 1544 public: 1545 CXXByrefHelpers(CharUnits alignment, QualType type, 1546 const Expr *copyExpr) 1547 : ByrefHelpers(alignment), VarType(type), CopyExpr(copyExpr) {} 1548 1549 bool needsCopy() const { return CopyExpr != 0; } 1550 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField, 1551 llvm::Value *srcField) { 1552 if (!CopyExpr) return; 1553 CGF.EmitSynthesizedCXXCopyCtor(destField, srcField, CopyExpr); 1554 } 1555 1556 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) { 1557 EHScopeStack::stable_iterator cleanupDepth = CGF.EHStack.stable_begin(); 1558 CGF.PushDestructorCleanup(VarType, field); 1559 CGF.PopCleanupBlocks(cleanupDepth); 1560 } 1561 1562 void profileImpl(llvm::FoldingSetNodeID &id) const { 1563 id.AddPointer(VarType.getCanonicalType().getAsOpaquePtr()); 1564 } 1565 }; 1566 } // end anonymous namespace 1567 1568 static llvm::Constant * 1569 generateByrefCopyHelper(CodeGenFunction &CGF, 1570 llvm::StructType &byrefType, 1571 CodeGenModule::ByrefHelpers &byrefInfo) { 1572 ASTContext &Context = CGF.getContext(); 1573 1574 QualType R = Context.VoidTy; 1575 1576 FunctionArgList args; 1577 ImplicitParamDecl dst(0, SourceLocation(), 0, Context.VoidPtrTy); 1578 args.push_back(&dst); 1579 1580 ImplicitParamDecl src(0, SourceLocation(), 0, Context.VoidPtrTy); 1581 args.push_back(&src); 1582 1583 const CGFunctionInfo &FI = 1584 CGF.CGM.getTypes().arrangeFunctionDeclaration(R, args, 1585 FunctionType::ExtInfo(), 1586 /*variadic*/ false); 1587 1588 CodeGenTypes &Types = CGF.CGM.getTypes(); 1589 llvm::FunctionType *LTy = Types.GetFunctionType(FI); 1590 1591 // FIXME: We'd like to put these into a mergable by content, with 1592 // internal linkage. 1593 llvm::Function *Fn = 1594 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, 1595 "__Block_byref_object_copy_", &CGF.CGM.getModule()); 1596 1597 IdentifierInfo *II 1598 = &Context.Idents.get("__Block_byref_object_copy_"); 1599 1600 FunctionDecl *FD = FunctionDecl::Create(Context, 1601 Context.getTranslationUnitDecl(), 1602 SourceLocation(), 1603 SourceLocation(), II, R, 0, 1604 SC_Static, 1605 SC_None, 1606 false, false); 1607 1608 CGF.StartFunction(FD, R, Fn, FI, args, SourceLocation()); 1609 1610 if (byrefInfo.needsCopy()) { 1611 llvm::Type *byrefPtrType = byrefType.getPointerTo(0); 1612 1613 // dst->x 1614 llvm::Value *destField = CGF.GetAddrOfLocalVar(&dst); 1615 destField = CGF.Builder.CreateLoad(destField); 1616 destField = CGF.Builder.CreateBitCast(destField, byrefPtrType); 1617 destField = CGF.Builder.CreateStructGEP(destField, 6, "x"); 1618 1619 // src->x 1620 llvm::Value *srcField = CGF.GetAddrOfLocalVar(&src); 1621 srcField = CGF.Builder.CreateLoad(srcField); 1622 srcField = CGF.Builder.CreateBitCast(srcField, byrefPtrType); 1623 srcField = CGF.Builder.CreateStructGEP(srcField, 6, "x"); 1624 1625 byrefInfo.emitCopy(CGF, destField, srcField); 1626 } 1627 1628 CGF.FinishFunction(); 1629 1630 return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy); 1631 } 1632 1633 /// Build the copy helper for a __block variable. 1634 static llvm::Constant *buildByrefCopyHelper(CodeGenModule &CGM, 1635 llvm::StructType &byrefType, 1636 CodeGenModule::ByrefHelpers &info) { 1637 CodeGenFunction CGF(CGM); 1638 return generateByrefCopyHelper(CGF, byrefType, info); 1639 } 1640 1641 /// Generate code for a __block variable's dispose helper. 1642 static llvm::Constant * 1643 generateByrefDisposeHelper(CodeGenFunction &CGF, 1644 llvm::StructType &byrefType, 1645 CodeGenModule::ByrefHelpers &byrefInfo) { 1646 ASTContext &Context = CGF.getContext(); 1647 QualType R = Context.VoidTy; 1648 1649 FunctionArgList args; 1650 ImplicitParamDecl src(0, SourceLocation(), 0, Context.VoidPtrTy); 1651 args.push_back(&src); 1652 1653 const CGFunctionInfo &FI = 1654 CGF.CGM.getTypes().arrangeFunctionDeclaration(R, args, 1655 FunctionType::ExtInfo(), 1656 /*variadic*/ false); 1657 1658 CodeGenTypes &Types = CGF.CGM.getTypes(); 1659 llvm::FunctionType *LTy = Types.GetFunctionType(FI); 1660 1661 // FIXME: We'd like to put these into a mergable by content, with 1662 // internal linkage. 1663 llvm::Function *Fn = 1664 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, 1665 "__Block_byref_object_dispose_", 1666 &CGF.CGM.getModule()); 1667 1668 IdentifierInfo *II 1669 = &Context.Idents.get("__Block_byref_object_dispose_"); 1670 1671 FunctionDecl *FD = FunctionDecl::Create(Context, 1672 Context.getTranslationUnitDecl(), 1673 SourceLocation(), 1674 SourceLocation(), II, R, 0, 1675 SC_Static, 1676 SC_None, 1677 false, false); 1678 CGF.StartFunction(FD, R, Fn, FI, args, SourceLocation()); 1679 1680 if (byrefInfo.needsDispose()) { 1681 llvm::Value *V = CGF.GetAddrOfLocalVar(&src); 1682 V = CGF.Builder.CreateLoad(V); 1683 V = CGF.Builder.CreateBitCast(V, byrefType.getPointerTo(0)); 1684 V = CGF.Builder.CreateStructGEP(V, 6, "x"); 1685 1686 byrefInfo.emitDispose(CGF, V); 1687 } 1688 1689 CGF.FinishFunction(); 1690 1691 return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy); 1692 } 1693 1694 /// Build the dispose helper for a __block variable. 1695 static llvm::Constant *buildByrefDisposeHelper(CodeGenModule &CGM, 1696 llvm::StructType &byrefType, 1697 CodeGenModule::ByrefHelpers &info) { 1698 CodeGenFunction CGF(CGM); 1699 return generateByrefDisposeHelper(CGF, byrefType, info); 1700 } 1701 1702 /// 1703 template <class T> static T *buildByrefHelpers(CodeGenModule &CGM, 1704 llvm::StructType &byrefTy, 1705 T &byrefInfo) { 1706 // Increase the field's alignment to be at least pointer alignment, 1707 // since the layout of the byref struct will guarantee at least that. 1708 byrefInfo.Alignment = std::max(byrefInfo.Alignment, 1709 CharUnits::fromQuantity(CGM.PointerAlignInBytes)); 1710 1711 llvm::FoldingSetNodeID id; 1712 byrefInfo.Profile(id); 1713 1714 void *insertPos; 1715 CodeGenModule::ByrefHelpers *node 1716 = CGM.ByrefHelpersCache.FindNodeOrInsertPos(id, insertPos); 1717 if (node) return static_cast<T*>(node); 1718 1719 byrefInfo.CopyHelper = buildByrefCopyHelper(CGM, byrefTy, byrefInfo); 1720 byrefInfo.DisposeHelper = buildByrefDisposeHelper(CGM, byrefTy, byrefInfo); 1721 1722 T *copy = new (CGM.getContext()) T(byrefInfo); 1723 CGM.ByrefHelpersCache.InsertNode(copy, insertPos); 1724 return copy; 1725 } 1726 1727 CodeGenModule::ByrefHelpers * 1728 CodeGenFunction::buildByrefHelpers(llvm::StructType &byrefType, 1729 const AutoVarEmission &emission) { 1730 const VarDecl &var = *emission.Variable; 1731 QualType type = var.getType(); 1732 1733 if (const CXXRecordDecl *record = type->getAsCXXRecordDecl()) { 1734 const Expr *copyExpr = CGM.getContext().getBlockVarCopyInits(&var); 1735 if (!copyExpr && record->hasTrivialDestructor()) return 0; 1736 1737 CXXByrefHelpers byrefInfo(emission.Alignment, type, copyExpr); 1738 return ::buildByrefHelpers(CGM, byrefType, byrefInfo); 1739 } 1740 1741 // Otherwise, if we don't have a retainable type, there's nothing to do. 1742 // that the runtime does extra copies. 1743 if (!type->isObjCRetainableType()) return 0; 1744 1745 Qualifiers qs = type.getQualifiers(); 1746 1747 // If we have lifetime, that dominates. 1748 if (Qualifiers::ObjCLifetime lifetime = qs.getObjCLifetime()) { 1749 assert(getLangOpts().ObjCAutoRefCount); 1750 1751 switch (lifetime) { 1752 case Qualifiers::OCL_None: llvm_unreachable("impossible"); 1753 1754 // These are just bits as far as the runtime is concerned. 1755 case Qualifiers::OCL_ExplicitNone: 1756 case Qualifiers::OCL_Autoreleasing: 1757 return 0; 1758 1759 // Tell the runtime that this is ARC __weak, called by the 1760 // byref routines. 1761 case Qualifiers::OCL_Weak: { 1762 ARCWeakByrefHelpers byrefInfo(emission.Alignment); 1763 return ::buildByrefHelpers(CGM, byrefType, byrefInfo); 1764 } 1765 1766 // ARC __strong __block variables need to be retained. 1767 case Qualifiers::OCL_Strong: 1768 // Block pointers need to be copied, and there's no direct 1769 // transfer possible. 1770 if (type->isBlockPointerType()) { 1771 ARCStrongBlockByrefHelpers byrefInfo(emission.Alignment); 1772 return ::buildByrefHelpers(CGM, byrefType, byrefInfo); 1773 1774 // Otherwise, we transfer ownership of the retain from the stack 1775 // to the heap. 1776 } else { 1777 ARCStrongByrefHelpers byrefInfo(emission.Alignment); 1778 return ::buildByrefHelpers(CGM, byrefType, byrefInfo); 1779 } 1780 } 1781 llvm_unreachable("fell out of lifetime switch!"); 1782 } 1783 1784 BlockFieldFlags flags; 1785 if (type->isBlockPointerType()) { 1786 flags |= BLOCK_FIELD_IS_BLOCK; 1787 } else if (CGM.getContext().isObjCNSObjectType(type) || 1788 type->isObjCObjectPointerType()) { 1789 flags |= BLOCK_FIELD_IS_OBJECT; 1790 } else { 1791 return 0; 1792 } 1793 1794 if (type.isObjCGCWeak()) 1795 flags |= BLOCK_FIELD_IS_WEAK; 1796 1797 ObjectByrefHelpers byrefInfo(emission.Alignment, flags); 1798 return ::buildByrefHelpers(CGM, byrefType, byrefInfo); 1799 } 1800 1801 unsigned CodeGenFunction::getByRefValueLLVMField(const ValueDecl *VD) const { 1802 assert(ByRefValueInfo.count(VD) && "Did not find value!"); 1803 1804 return ByRefValueInfo.find(VD)->second.second; 1805 } 1806 1807 llvm::Value *CodeGenFunction::BuildBlockByrefAddress(llvm::Value *BaseAddr, 1808 const VarDecl *V) { 1809 llvm::Value *Loc = Builder.CreateStructGEP(BaseAddr, 1, "forwarding"); 1810 Loc = Builder.CreateLoad(Loc); 1811 Loc = Builder.CreateStructGEP(Loc, getByRefValueLLVMField(V), 1812 V->getNameAsString()); 1813 return Loc; 1814 } 1815 1816 /// BuildByRefType - This routine changes a __block variable declared as T x 1817 /// into: 1818 /// 1819 /// struct { 1820 /// void *__isa; 1821 /// void *__forwarding; 1822 /// int32_t __flags; 1823 /// int32_t __size; 1824 /// void *__copy_helper; // only if needed 1825 /// void *__destroy_helper; // only if needed 1826 /// char padding[X]; // only if needed 1827 /// T x; 1828 /// } x 1829 /// 1830 llvm::Type *CodeGenFunction::BuildByRefType(const VarDecl *D) { 1831 std::pair<llvm::Type *, unsigned> &Info = ByRefValueInfo[D]; 1832 if (Info.first) 1833 return Info.first; 1834 1835 QualType Ty = D->getType(); 1836 1837 SmallVector<llvm::Type *, 8> types; 1838 1839 llvm::StructType *ByRefType = 1840 llvm::StructType::create(getLLVMContext(), 1841 "struct.__block_byref_" + D->getNameAsString()); 1842 1843 // void *__isa; 1844 types.push_back(Int8PtrTy); 1845 1846 // void *__forwarding; 1847 types.push_back(llvm::PointerType::getUnqual(ByRefType)); 1848 1849 // int32_t __flags; 1850 types.push_back(Int32Ty); 1851 1852 // int32_t __size; 1853 types.push_back(Int32Ty); 1854 1855 bool HasCopyAndDispose = 1856 (Ty->isObjCRetainableType()) || getContext().getBlockVarCopyInits(D); 1857 if (HasCopyAndDispose) { 1858 /// void *__copy_helper; 1859 types.push_back(Int8PtrTy); 1860 1861 /// void *__destroy_helper; 1862 types.push_back(Int8PtrTy); 1863 } 1864 1865 bool Packed = false; 1866 CharUnits Align = getContext().getDeclAlign(D); 1867 if (Align > getContext().toCharUnitsFromBits(Target.getPointerAlign(0))) { 1868 // We have to insert padding. 1869 1870 // The struct above has 2 32-bit integers. 1871 unsigned CurrentOffsetInBytes = 4 * 2; 1872 1873 // And either 2 or 4 pointers. 1874 CurrentOffsetInBytes += (HasCopyAndDispose ? 4 : 2) * 1875 CGM.getTargetData().getTypeAllocSize(Int8PtrTy); 1876 1877 // Align the offset. 1878 unsigned AlignedOffsetInBytes = 1879 llvm::RoundUpToAlignment(CurrentOffsetInBytes, Align.getQuantity()); 1880 1881 unsigned NumPaddingBytes = AlignedOffsetInBytes - CurrentOffsetInBytes; 1882 if (NumPaddingBytes > 0) { 1883 llvm::Type *Ty = Int8Ty; 1884 // FIXME: We need a sema error for alignment larger than the minimum of 1885 // the maximal stack alignment and the alignment of malloc on the system. 1886 if (NumPaddingBytes > 1) 1887 Ty = llvm::ArrayType::get(Ty, NumPaddingBytes); 1888 1889 types.push_back(Ty); 1890 1891 // We want a packed struct. 1892 Packed = true; 1893 } 1894 } 1895 1896 // T x; 1897 types.push_back(ConvertTypeForMem(Ty)); 1898 1899 ByRefType->setBody(types, Packed); 1900 1901 Info.first = ByRefType; 1902 1903 Info.second = types.size() - 1; 1904 1905 return Info.first; 1906 } 1907 1908 /// Initialize the structural components of a __block variable, i.e. 1909 /// everything but the actual object. 1910 void CodeGenFunction::emitByrefStructureInit(const AutoVarEmission &emission) { 1911 // Find the address of the local. 1912 llvm::Value *addr = emission.Address; 1913 1914 // That's an alloca of the byref structure type. 1915 llvm::StructType *byrefType = cast<llvm::StructType>( 1916 cast<llvm::PointerType>(addr->getType())->getElementType()); 1917 1918 // Build the byref helpers if necessary. This is null if we don't need any. 1919 CodeGenModule::ByrefHelpers *helpers = 1920 buildByrefHelpers(*byrefType, emission); 1921 1922 const VarDecl &D = *emission.Variable; 1923 QualType type = D.getType(); 1924 1925 llvm::Value *V; 1926 1927 // Initialize the 'isa', which is just 0 or 1. 1928 int isa = 0; 1929 if (type.isObjCGCWeak()) 1930 isa = 1; 1931 V = Builder.CreateIntToPtr(Builder.getInt32(isa), Int8PtrTy, "isa"); 1932 Builder.CreateStore(V, Builder.CreateStructGEP(addr, 0, "byref.isa")); 1933 1934 // Store the address of the variable into its own forwarding pointer. 1935 Builder.CreateStore(addr, 1936 Builder.CreateStructGEP(addr, 1, "byref.forwarding")); 1937 1938 // Blocks ABI: 1939 // c) the flags field is set to either 0 if no helper functions are 1940 // needed or BLOCK_HAS_COPY_DISPOSE if they are, 1941 BlockFlags flags; 1942 if (helpers) flags |= BLOCK_HAS_COPY_DISPOSE; 1943 Builder.CreateStore(llvm::ConstantInt::get(IntTy, flags.getBitMask()), 1944 Builder.CreateStructGEP(addr, 2, "byref.flags")); 1945 1946 CharUnits byrefSize = CGM.GetTargetTypeStoreSize(byrefType); 1947 V = llvm::ConstantInt::get(IntTy, byrefSize.getQuantity()); 1948 Builder.CreateStore(V, Builder.CreateStructGEP(addr, 3, "byref.size")); 1949 1950 if (helpers) { 1951 llvm::Value *copy_helper = Builder.CreateStructGEP(addr, 4); 1952 Builder.CreateStore(helpers->CopyHelper, copy_helper); 1953 1954 llvm::Value *destroy_helper = Builder.CreateStructGEP(addr, 5); 1955 Builder.CreateStore(helpers->DisposeHelper, destroy_helper); 1956 } 1957 } 1958 1959 void CodeGenFunction::BuildBlockRelease(llvm::Value *V, BlockFieldFlags flags) { 1960 llvm::Value *F = CGM.getBlockObjectDispose(); 1961 llvm::Value *N; 1962 V = Builder.CreateBitCast(V, Int8PtrTy); 1963 N = llvm::ConstantInt::get(Int32Ty, flags.getBitMask()); 1964 Builder.CreateCall2(F, V, N); 1965 } 1966 1967 namespace { 1968 struct CallBlockRelease : EHScopeStack::Cleanup { 1969 llvm::Value *Addr; 1970 CallBlockRelease(llvm::Value *Addr) : Addr(Addr) {} 1971 1972 void Emit(CodeGenFunction &CGF, Flags flags) { 1973 // Should we be passing FIELD_IS_WEAK here? 1974 CGF.BuildBlockRelease(Addr, BLOCK_FIELD_IS_BYREF); 1975 } 1976 }; 1977 } 1978 1979 /// Enter a cleanup to destroy a __block variable. Note that this 1980 /// cleanup should be a no-op if the variable hasn't left the stack 1981 /// yet; if a cleanup is required for the variable itself, that needs 1982 /// to be done externally. 1983 void CodeGenFunction::enterByrefCleanup(const AutoVarEmission &emission) { 1984 // We don't enter this cleanup if we're in pure-GC mode. 1985 if (CGM.getLangOpts().getGC() == LangOptions::GCOnly) 1986 return; 1987 1988 EHStack.pushCleanup<CallBlockRelease>(NormalAndEHCleanup, emission.Address); 1989 } 1990 1991 /// Adjust the declaration of something from the blocks API. 1992 static void configureBlocksRuntimeObject(CodeGenModule &CGM, 1993 llvm::Constant *C) { 1994 if (!CGM.getLangOpts().BlocksRuntimeOptional) return; 1995 1996 llvm::GlobalValue *GV = cast<llvm::GlobalValue>(C->stripPointerCasts()); 1997 if (GV->isDeclaration() && 1998 GV->getLinkage() == llvm::GlobalValue::ExternalLinkage) 1999 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage); 2000 } 2001 2002 llvm::Constant *CodeGenModule::getBlockObjectDispose() { 2003 if (BlockObjectDispose) 2004 return BlockObjectDispose; 2005 2006 llvm::Type *args[] = { Int8PtrTy, Int32Ty }; 2007 llvm::FunctionType *fty 2008 = llvm::FunctionType::get(VoidTy, args, false); 2009 BlockObjectDispose = CreateRuntimeFunction(fty, "_Block_object_dispose"); 2010 configureBlocksRuntimeObject(*this, BlockObjectDispose); 2011 return BlockObjectDispose; 2012 } 2013 2014 llvm::Constant *CodeGenModule::getBlockObjectAssign() { 2015 if (BlockObjectAssign) 2016 return BlockObjectAssign; 2017 2018 llvm::Type *args[] = { Int8PtrTy, Int8PtrTy, Int32Ty }; 2019 llvm::FunctionType *fty 2020 = llvm::FunctionType::get(VoidTy, args, false); 2021 BlockObjectAssign = CreateRuntimeFunction(fty, "_Block_object_assign"); 2022 configureBlocksRuntimeObject(*this, BlockObjectAssign); 2023 return BlockObjectAssign; 2024 } 2025 2026 llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() { 2027 if (NSConcreteGlobalBlock) 2028 return NSConcreteGlobalBlock; 2029 2030 NSConcreteGlobalBlock = GetOrCreateLLVMGlobal("_NSConcreteGlobalBlock", 2031 Int8PtrTy->getPointerTo(), 0); 2032 configureBlocksRuntimeObject(*this, NSConcreteGlobalBlock); 2033 return NSConcreteGlobalBlock; 2034 } 2035 2036 llvm::Constant *CodeGenModule::getNSConcreteStackBlock() { 2037 if (NSConcreteStackBlock) 2038 return NSConcreteStackBlock; 2039 2040 NSConcreteStackBlock = GetOrCreateLLVMGlobal("_NSConcreteStackBlock", 2041 Int8PtrTy->getPointerTo(), 0); 2042 configureBlocksRuntimeObject(*this, NSConcreteStackBlock); 2043 return NSConcreteStackBlock; 2044 } 2045