1 //===--- CGBlocks.cpp - Emit LLVM Code for declarations ---------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This contains code to emit blocks.
12 //===----------------------------------------------------------------------===//
15 #include "CGDebugInfo.h"
16 #include "CGObjCRuntime.h"
17 #include "CodeGenFunction.h"
18 #include "CodeGenModule.h"
19 #include "clang/CodeGen/ConstantInitBuilder.h"
20 #include "clang/AST/DeclObjC.h"
21 #include "llvm/ADT/SmallSet.h"
22 #include "llvm/IR/CallSite.h"
23 #include "llvm/IR/DataLayout.h"
24 #include "llvm/IR/Module.h"
28 using namespace clang;
29 using namespace CodeGen;
31 CGBlockInfo::CGBlockInfo(const BlockDecl *block, StringRef name)
32 : Name(name), CXXThisIndex(0), CanBeGlobal(false), NeedsCopyDispose(false),
33 HasCXXObject(false), UsesStret(false), HasCapturedVariableLayout(false),
34 LocalAddress(Address::invalid()), StructureType(nullptr), Block(block),
35 DominatingIP(nullptr) {
37 // Skip asm prefix, if any. 'name' is usually taken directly from
38 // the mangled name of the enclosing function.
39 if (!name.empty() && name[0] == '\01')
40 name = name.substr(1);
43 // Anchor the vtable to this translation unit.
44 BlockByrefHelpers::~BlockByrefHelpers() {}
46 /// Build the given block as a global block.
47 static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
48 const CGBlockInfo &blockInfo,
49 llvm::Constant *blockFn);
51 /// Build the helper function to copy a block.
52 static llvm::Constant *buildCopyHelper(CodeGenModule &CGM,
53 const CGBlockInfo &blockInfo) {
54 return CodeGenFunction(CGM).GenerateCopyHelperFunction(blockInfo);
57 /// Build the helper function to dispose of a block.
58 static llvm::Constant *buildDisposeHelper(CodeGenModule &CGM,
59 const CGBlockInfo &blockInfo) {
60 return CodeGenFunction(CGM).GenerateDestroyHelperFunction(blockInfo);
63 /// buildBlockDescriptor - Build the block descriptor meta-data for a block.
64 /// buildBlockDescriptor is accessed from 5th field of the Block_literal
65 /// meta-data and contains stationary information about the block literal.
66 /// Its definition will have 4 (or optinally 6) words.
68 /// struct Block_descriptor {
69 /// unsigned long reserved;
70 /// unsigned long size; // size of Block_literal metadata in bytes.
71 /// void *copy_func_helper_decl; // optional copy helper.
72 /// void *destroy_func_decl; // optioanl destructor helper.
73 /// void *block_method_encoding_address; // @encode for block literal signature.
74 /// void *block_layout_info; // encoding of captured block variables.
77 static llvm::Constant *buildBlockDescriptor(CodeGenModule &CGM,
78 const CGBlockInfo &blockInfo) {
79 ASTContext &C = CGM.getContext();
81 llvm::IntegerType *ulong =
82 cast<llvm::IntegerType>(CGM.getTypes().ConvertType(C.UnsignedLongTy));
83 llvm::PointerType *i8p = nullptr;
84 if (CGM.getLangOpts().OpenCL)
86 llvm::Type::getInt8PtrTy(
87 CGM.getLLVMContext(), C.getTargetAddressSpace(LangAS::opencl_constant));
91 ConstantInitBuilder builder(CGM);
92 auto elements = builder.beginStruct();
95 elements.addInt(ulong, 0);
98 // FIXME: What is the right way to say this doesn't fit? We should give
99 // a user diagnostic in that case. Better fix would be to change the
101 elements.addInt(ulong, blockInfo.BlockSize.getQuantity());
103 // Optional copy/dispose helpers.
104 if (blockInfo.NeedsCopyDispose) {
105 // copy_func_helper_decl
106 elements.add(buildCopyHelper(CGM, blockInfo));
109 elements.add(buildDisposeHelper(CGM, blockInfo));
112 // Signature. Mandatory ObjC-style method descriptor @encode sequence.
113 std::string typeAtEncoding =
114 CGM.getContext().getObjCEncodingForBlock(blockInfo.getBlockExpr());
115 elements.add(llvm::ConstantExpr::getBitCast(
116 CGM.GetAddrOfConstantCString(typeAtEncoding).getPointer(), i8p));
119 if (C.getLangOpts().ObjC1) {
120 if (CGM.getLangOpts().getGC() != LangOptions::NonGC)
121 elements.add(CGM.getObjCRuntime().BuildGCBlockLayout(CGM, blockInfo));
123 elements.add(CGM.getObjCRuntime().BuildRCBlockLayout(CGM, blockInfo));
126 elements.addNullPointer(i8p);
128 unsigned AddrSpace = 0;
129 if (C.getLangOpts().OpenCL)
130 AddrSpace = C.getTargetAddressSpace(LangAS::opencl_constant);
132 llvm::GlobalVariable *global =
133 elements.finishAndCreateGlobal("__block_descriptor_tmp",
134 CGM.getPointerAlign(),
136 llvm::GlobalValue::InternalLinkage,
139 return llvm::ConstantExpr::getBitCast(global, CGM.getBlockDescriptorType());
143 Purely notional variadic template describing the layout of a block.
145 template <class _ResultType, class... _ParamTypes, class... _CaptureTypes>
146 struct Block_literal {
147 /// Initialized to one of:
148 /// extern void *_NSConcreteStackBlock[];
149 /// extern void *_NSConcreteGlobalBlock[];
151 /// In theory, we could start one off malloc'ed by setting
152 /// BLOCK_NEEDS_FREE, giving it a refcount of 1, and using
154 /// extern void *_NSConcreteMallocBlock[];
155 struct objc_class *isa;
157 /// These are the flags (with corresponding bit number) that the
158 /// compiler is actually supposed to know about.
159 /// 25. BLOCK_HAS_COPY_DISPOSE - indicates that the block
160 /// descriptor provides copy and dispose helper functions
161 /// 26. BLOCK_HAS_CXX_OBJ - indicates that there's a captured
162 /// object with a nontrivial destructor or copy constructor
163 /// 28. BLOCK_IS_GLOBAL - indicates that the block is allocated
165 /// 29. BLOCK_USE_STRET - indicates that the block function
166 /// uses stret, which objc_msgSend needs to know about
167 /// 30. BLOCK_HAS_SIGNATURE - indicates that the block has an
168 /// @encoded signature string
169 /// And we're not supposed to manipulate these:
170 /// 24. BLOCK_NEEDS_FREE - indicates that the block has been moved
171 /// to malloc'ed memory
172 /// 27. BLOCK_IS_GC - indicates that the block has been moved to
173 /// to GC-allocated memory
174 /// Additionally, the bottom 16 bits are a reference count which
175 /// should be zero on the stack.
178 /// Reserved; should be zero-initialized.
181 /// Function pointer generated from block literal.
182 _ResultType (*invoke)(Block_literal *, _ParamTypes...);
184 /// Block description metadata generated from block literal.
185 struct Block_descriptor *block_descriptor;
187 /// Captured values follow.
188 _CapturesTypes captures...;
193 /// A chunk of data that we actually have to capture in the block.
194 struct BlockLayoutChunk {
197 Qualifiers::ObjCLifetime Lifetime;
198 const BlockDecl::Capture *Capture; // null for 'this'
202 BlockLayoutChunk(CharUnits align, CharUnits size,
203 Qualifiers::ObjCLifetime lifetime,
204 const BlockDecl::Capture *capture,
205 llvm::Type *type, QualType fieldType)
206 : Alignment(align), Size(size), Lifetime(lifetime),
207 Capture(capture), Type(type), FieldType(fieldType) {}
209 /// Tell the block info that this chunk has the given field index.
210 void setIndex(CGBlockInfo &info, unsigned index, CharUnits offset) {
212 info.CXXThisIndex = index;
213 info.CXXThisOffset = offset;
215 auto C = CGBlockInfo::Capture::makeIndex(index, offset, FieldType);
216 info.Captures.insert({Capture->getVariable(), C});
221 /// Order by 1) all __strong together 2) next, all byfref together 3) next,
222 /// all __weak together. Preserve descending alignment in all situations.
223 bool operator<(const BlockLayoutChunk &left, const BlockLayoutChunk &right) {
224 if (left.Alignment != right.Alignment)
225 return left.Alignment > right.Alignment;
227 auto getPrefOrder = [](const BlockLayoutChunk &chunk) {
228 if (chunk.Capture && chunk.Capture->isByRef())
230 if (chunk.Lifetime == Qualifiers::OCL_Strong)
232 if (chunk.Lifetime == Qualifiers::OCL_Weak)
237 return getPrefOrder(left) < getPrefOrder(right);
239 } // end anonymous namespace
241 /// Determines if the given type is safe for constant capture in C++.
242 static bool isSafeForCXXConstantCapture(QualType type) {
243 const RecordType *recordType =
244 type->getBaseElementTypeUnsafe()->getAs<RecordType>();
246 // Only records can be unsafe.
247 if (!recordType) return true;
249 const auto *record = cast<CXXRecordDecl>(recordType->getDecl());
251 // Maintain semantics for classes with non-trivial dtors or copy ctors.
252 if (!record->hasTrivialDestructor()) return false;
253 if (record->hasNonTrivialCopyConstructor()) return false;
255 // Otherwise, we just have to make sure there aren't any mutable
256 // fields that might have changed since initialization.
257 return !record->hasMutableFields();
260 /// It is illegal to modify a const object after initialization.
261 /// Therefore, if a const object has a constant initializer, we don't
262 /// actually need to keep storage for it in the block; we'll just
263 /// rematerialize it at the start of the block function. This is
264 /// acceptable because we make no promises about address stability of
265 /// captured variables.
266 static llvm::Constant *tryCaptureAsConstant(CodeGenModule &CGM,
267 CodeGenFunction *CGF,
268 const VarDecl *var) {
269 // Return if this is a function parameter. We shouldn't try to
270 // rematerialize default arguments of function parameters.
271 if (isa<ParmVarDecl>(var))
274 QualType type = var->getType();
276 // We can only do this if the variable is const.
277 if (!type.isConstQualified()) return nullptr;
279 // Furthermore, in C++ we have to worry about mutable fields:
280 // C++ [dcl.type.cv]p4:
281 // Except that any class member declared mutable can be
282 // modified, any attempt to modify a const object during its
283 // lifetime results in undefined behavior.
284 if (CGM.getLangOpts().CPlusPlus && !isSafeForCXXConstantCapture(type))
287 // If the variable doesn't have any initializer (shouldn't this be
288 // invalid?), it's not clear what we should do. Maybe capture as
290 const Expr *init = var->getInit();
291 if (!init) return nullptr;
293 return CGM.EmitConstantInit(*var, CGF);
296 /// Get the low bit of a nonzero character count. This is the
297 /// alignment of the nth byte if the 0th byte is universally aligned.
298 static CharUnits getLowBit(CharUnits v) {
299 return CharUnits::fromQuantity(v.getQuantity() & (~v.getQuantity() + 1));
302 static void initializeForBlockHeader(CodeGenModule &CGM, CGBlockInfo &info,
303 SmallVectorImpl<llvm::Type*> &elementTypes) {
304 // The header is basically 'struct { void *; int; int; void *; void *; }'.
305 // Assert that that struct is packed.
306 assert(CGM.getIntSize() <= CGM.getPointerSize());
307 assert(CGM.getIntAlign() <= CGM.getPointerAlign());
308 assert((2 * CGM.getIntSize()).isMultipleOf(CGM.getPointerAlign()));
310 info.BlockAlign = CGM.getPointerAlign();
311 info.BlockSize = 3 * CGM.getPointerSize() + 2 * CGM.getIntSize();
313 assert(elementTypes.empty());
314 elementTypes.push_back(CGM.VoidPtrTy);
315 elementTypes.push_back(CGM.IntTy);
316 elementTypes.push_back(CGM.IntTy);
317 elementTypes.push_back(CGM.VoidPtrTy);
318 elementTypes.push_back(CGM.getBlockDescriptorType());
321 static QualType getCaptureFieldType(const CodeGenFunction &CGF,
322 const BlockDecl::Capture &CI) {
323 const VarDecl *VD = CI.getVariable();
325 // If the variable is captured by an enclosing block or lambda expression,
326 // use the type of the capture field.
327 if (CGF.BlockInfo && CI.isNested())
328 return CGF.BlockInfo->getCapture(VD).fieldType();
329 if (auto *FD = CGF.LambdaCaptureFields.lookup(VD))
330 return FD->getType();
331 return VD->getType();
334 /// Compute the layout of the given block. Attempts to lay the block
335 /// out with minimal space requirements.
336 static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF,
338 ASTContext &C = CGM.getContext();
339 const BlockDecl *block = info.getBlockDecl();
341 SmallVector<llvm::Type*, 8> elementTypes;
342 initializeForBlockHeader(CGM, info, elementTypes);
344 if (!block->hasCaptures()) {
346 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true);
347 info.CanBeGlobal = true;
350 else if (C.getLangOpts().ObjC1 &&
351 CGM.getLangOpts().getGC() == LangOptions::NonGC)
352 info.HasCapturedVariableLayout = true;
354 // Collect the layout chunks.
355 SmallVector<BlockLayoutChunk, 16> layout;
356 layout.reserve(block->capturesCXXThis() +
357 (block->capture_end() - block->capture_begin()));
359 CharUnits maxFieldAlign;
362 if (block->capturesCXXThis()) {
363 assert(CGF && CGF->CurFuncDecl && isa<CXXMethodDecl>(CGF->CurFuncDecl) &&
364 "Can't capture 'this' outside a method");
365 QualType thisType = cast<CXXMethodDecl>(CGF->CurFuncDecl)->getThisType(C);
367 // Theoretically, this could be in a different address space, so
368 // don't assume standard pointer size/align.
369 llvm::Type *llvmType = CGM.getTypes().ConvertType(thisType);
370 std::pair<CharUnits,CharUnits> tinfo
371 = CGM.getContext().getTypeInfoInChars(thisType);
372 maxFieldAlign = std::max(maxFieldAlign, tinfo.second);
374 layout.push_back(BlockLayoutChunk(tinfo.second, tinfo.first,
375 Qualifiers::OCL_None,
376 nullptr, llvmType, thisType));
379 // Next, all the block captures.
380 for (const auto &CI : block->captures()) {
381 const VarDecl *variable = CI.getVariable();
384 // We have to copy/dispose of the __block reference.
385 info.NeedsCopyDispose = true;
387 // Just use void* instead of a pointer to the byref type.
388 CharUnits align = CGM.getPointerAlign();
389 maxFieldAlign = std::max(maxFieldAlign, align);
391 layout.push_back(BlockLayoutChunk(align, CGM.getPointerSize(),
392 Qualifiers::OCL_None, &CI,
393 CGM.VoidPtrTy, variable->getType()));
397 // Otherwise, build a layout chunk with the size and alignment of
399 if (llvm::Constant *constant = tryCaptureAsConstant(CGM, CGF, variable)) {
400 info.Captures[variable] = CGBlockInfo::Capture::makeConstant(constant);
404 // If we have a lifetime qualifier, honor it for capture purposes.
405 // That includes *not* copying it if it's __unsafe_unretained.
406 Qualifiers::ObjCLifetime lifetime =
407 variable->getType().getObjCLifetime();
410 case Qualifiers::OCL_None: llvm_unreachable("impossible");
411 case Qualifiers::OCL_ExplicitNone:
412 case Qualifiers::OCL_Autoreleasing:
415 case Qualifiers::OCL_Strong:
416 case Qualifiers::OCL_Weak:
417 info.NeedsCopyDispose = true;
420 // Block pointers require copy/dispose. So do Objective-C pointers.
421 } else if (variable->getType()->isObjCRetainableType()) {
422 // But honor the inert __unsafe_unretained qualifier, which doesn't
423 // actually make it into the type system.
424 if (variable->getType()->isObjCInertUnsafeUnretainedType()) {
425 lifetime = Qualifiers::OCL_ExplicitNone;
427 info.NeedsCopyDispose = true;
428 // used for mrr below.
429 lifetime = Qualifiers::OCL_Strong;
432 // So do types that require non-trivial copy construction.
433 } else if (CI.hasCopyExpr()) {
434 info.NeedsCopyDispose = true;
435 info.HasCXXObject = true;
437 // And so do types with destructors.
438 } else if (CGM.getLangOpts().CPlusPlus) {
439 if (const CXXRecordDecl *record =
440 variable->getType()->getAsCXXRecordDecl()) {
441 if (!record->hasTrivialDestructor()) {
442 info.HasCXXObject = true;
443 info.NeedsCopyDispose = true;
448 QualType VT = getCaptureFieldType(*CGF, CI);
449 CharUnits size = C.getTypeSizeInChars(VT);
450 CharUnits align = C.getDeclAlign(variable);
452 maxFieldAlign = std::max(maxFieldAlign, align);
454 llvm::Type *llvmType =
455 CGM.getTypes().ConvertTypeForMem(VT);
458 BlockLayoutChunk(align, size, lifetime, &CI, llvmType, VT));
461 // If that was everything, we're done here.
462 if (layout.empty()) {
464 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true);
465 info.CanBeGlobal = true;
469 // Sort the layout by alignment. We have to use a stable sort here
470 // to get reproducible results. There should probably be an
471 // llvm::array_pod_stable_sort.
472 std::stable_sort(layout.begin(), layout.end());
474 // Needed for blocks layout info.
475 info.BlockHeaderForcedGapOffset = info.BlockSize;
476 info.BlockHeaderForcedGapSize = CharUnits::Zero();
478 CharUnits &blockSize = info.BlockSize;
479 info.BlockAlign = std::max(maxFieldAlign, info.BlockAlign);
481 // Assuming that the first byte in the header is maximally aligned,
482 // get the alignment of the first byte following the header.
483 CharUnits endAlign = getLowBit(blockSize);
485 // If the end of the header isn't satisfactorily aligned for the
486 // maximum thing, look for things that are okay with the header-end
487 // alignment, and keep appending them until we get something that's
488 // aligned right. This algorithm is only guaranteed optimal if
489 // that condition is satisfied at some point; otherwise we can get
491 // header // next byte has alignment 4
492 // something_with_size_5; // next byte has alignment 1
493 // something_with_alignment_8;
494 // which has 7 bytes of padding, as opposed to the naive solution
495 // which might have less (?).
496 if (endAlign < maxFieldAlign) {
497 SmallVectorImpl<BlockLayoutChunk>::iterator
498 li = layout.begin() + 1, le = layout.end();
500 // Look for something that the header end is already
501 // satisfactorily aligned for.
502 for (; li != le && endAlign < li->Alignment; ++li)
505 // If we found something that's naturally aligned for the end of
506 // the header, keep adding things...
508 SmallVectorImpl<BlockLayoutChunk>::iterator first = li;
509 for (; li != le; ++li) {
510 assert(endAlign >= li->Alignment);
512 li->setIndex(info, elementTypes.size(), blockSize);
513 elementTypes.push_back(li->Type);
514 blockSize += li->Size;
515 endAlign = getLowBit(blockSize);
517 // ...until we get to the alignment of the maximum field.
518 if (endAlign >= maxFieldAlign) {
522 // Don't re-append everything we just appended.
523 layout.erase(first, li);
527 assert(endAlign == getLowBit(blockSize));
529 // At this point, we just have to add padding if the end align still
530 // isn't aligned right.
531 if (endAlign < maxFieldAlign) {
532 CharUnits newBlockSize = blockSize.alignTo(maxFieldAlign);
533 CharUnits padding = newBlockSize - blockSize;
535 // If we haven't yet added any fields, remember that there was an
536 // initial gap; this need to go into the block layout bit map.
537 if (blockSize == info.BlockHeaderForcedGapOffset) {
538 info.BlockHeaderForcedGapSize = padding;
541 elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty,
542 padding.getQuantity()));
543 blockSize = newBlockSize;
544 endAlign = getLowBit(blockSize); // might be > maxFieldAlign
547 assert(endAlign >= maxFieldAlign);
548 assert(endAlign == getLowBit(blockSize));
549 // Slam everything else on now. This works because they have
550 // strictly decreasing alignment and we expect that size is always a
551 // multiple of alignment.
552 for (SmallVectorImpl<BlockLayoutChunk>::iterator
553 li = layout.begin(), le = layout.end(); li != le; ++li) {
554 if (endAlign < li->Alignment) {
555 // size may not be multiple of alignment. This can only happen with
556 // an over-aligned variable. We will be adding a padding field to
557 // make the size be multiple of alignment.
558 CharUnits padding = li->Alignment - endAlign;
559 elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty,
560 padding.getQuantity()));
561 blockSize += padding;
562 endAlign = getLowBit(blockSize);
564 assert(endAlign >= li->Alignment);
565 li->setIndex(info, elementTypes.size(), blockSize);
566 elementTypes.push_back(li->Type);
567 blockSize += li->Size;
568 endAlign = getLowBit(blockSize);
572 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true);
575 /// Enter the scope of a block. This should be run at the entrance to
576 /// a full-expression so that the block's cleanups are pushed at the
577 /// right place in the stack.
578 static void enterBlockScope(CodeGenFunction &CGF, BlockDecl *block) {
579 assert(CGF.HaveInsertPoint());
581 // Allocate the block info and place it at the head of the list.
582 CGBlockInfo &blockInfo =
583 *new CGBlockInfo(block, CGF.CurFn->getName());
584 blockInfo.NextBlockInfo = CGF.FirstBlockInfo;
585 CGF.FirstBlockInfo = &blockInfo;
587 // Compute information about the layout, etc., of this block,
588 // pushing cleanups as necessary.
589 computeBlockInfo(CGF.CGM, &CGF, blockInfo);
591 // Nothing else to do if it can be global.
592 if (blockInfo.CanBeGlobal) return;
594 // Make the allocation for the block.
595 blockInfo.LocalAddress = CGF.CreateTempAlloca(blockInfo.StructureType,
596 blockInfo.BlockAlign, "block");
598 // If there are cleanups to emit, enter them (but inactive).
599 if (!blockInfo.NeedsCopyDispose) return;
601 // Walk through the captures (in order) and find the ones not
602 // captured by constant.
603 for (const auto &CI : block->captures()) {
604 // Ignore __block captures; there's nothing special in the
605 // on-stack block that we need to do for them.
606 if (CI.isByRef()) continue;
608 // Ignore variables that are constant-captured.
609 const VarDecl *variable = CI.getVariable();
610 CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
611 if (capture.isConstant()) continue;
613 // Ignore objects that aren't destructed.
614 QualType VT = getCaptureFieldType(CGF, CI);
615 QualType::DestructionKind dtorKind = VT.isDestructedType();
616 if (dtorKind == QualType::DK_none) continue;
618 CodeGenFunction::Destroyer *destroyer;
620 // Block captures count as local values and have imprecise semantics.
621 // They also can't be arrays, so need to worry about that.
622 if (dtorKind == QualType::DK_objc_strong_lifetime) {
623 destroyer = CodeGenFunction::destroyARCStrongImprecise;
625 destroyer = CGF.getDestroyer(dtorKind);
628 // GEP down to the address.
629 Address addr = CGF.Builder.CreateStructGEP(blockInfo.LocalAddress,
631 capture.getOffset());
633 // We can use that GEP as the dominating IP.
634 if (!blockInfo.DominatingIP)
635 blockInfo.DominatingIP = cast<llvm::Instruction>(addr.getPointer());
637 CleanupKind cleanupKind = InactiveNormalCleanup;
638 bool useArrayEHCleanup = CGF.needsEHCleanup(dtorKind);
639 if (useArrayEHCleanup)
640 cleanupKind = InactiveNormalAndEHCleanup;
642 CGF.pushDestroy(cleanupKind, addr, VT,
643 destroyer, useArrayEHCleanup);
645 // Remember where that cleanup was.
646 capture.setCleanup(CGF.EHStack.stable_begin());
650 /// Enter a full-expression with a non-trivial number of objects to
651 /// clean up. This is in this file because, at the moment, the only
652 /// kind of cleanup object is a BlockDecl*.
653 void CodeGenFunction::enterNonTrivialFullExpression(const ExprWithCleanups *E) {
654 assert(E->getNumObjects() != 0);
655 ArrayRef<ExprWithCleanups::CleanupObject> cleanups = E->getObjects();
656 for (ArrayRef<ExprWithCleanups::CleanupObject>::iterator
657 i = cleanups.begin(), e = cleanups.end(); i != e; ++i) {
658 enterBlockScope(*this, *i);
662 /// Find the layout for the given block in a linked list and remove it.
663 static CGBlockInfo *findAndRemoveBlockInfo(CGBlockInfo **head,
664 const BlockDecl *block) {
666 assert(head && *head);
667 CGBlockInfo *cur = *head;
669 // If this is the block we're looking for, splice it out of the list.
670 if (cur->getBlockDecl() == block) {
671 *head = cur->NextBlockInfo;
675 head = &cur->NextBlockInfo;
679 /// Destroy a chain of block layouts.
680 void CodeGenFunction::destroyBlockInfos(CGBlockInfo *head) {
681 assert(head && "destroying an empty chain");
683 CGBlockInfo *cur = head;
684 head = cur->NextBlockInfo;
686 } while (head != nullptr);
689 /// Emit a block literal expression in the current function.
690 llvm::Value *CodeGenFunction::EmitBlockLiteral(const BlockExpr *blockExpr) {
691 // If the block has no captures, we won't have a pre-computed
693 if (!blockExpr->getBlockDecl()->hasCaptures()) {
694 if (llvm::Constant *Block = CGM.getAddrOfGlobalBlockIfEmitted(blockExpr))
696 CGBlockInfo blockInfo(blockExpr->getBlockDecl(), CurFn->getName());
697 computeBlockInfo(CGM, this, blockInfo);
698 blockInfo.BlockExpression = blockExpr;
699 return EmitBlockLiteral(blockInfo);
702 // Find the block info for this block and take ownership of it.
703 std::unique_ptr<CGBlockInfo> blockInfo;
704 blockInfo.reset(findAndRemoveBlockInfo(&FirstBlockInfo,
705 blockExpr->getBlockDecl()));
707 blockInfo->BlockExpression = blockExpr;
708 return EmitBlockLiteral(*blockInfo);
711 llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo) {
712 // Using the computed layout, generate the actual block function.
713 bool isLambdaConv = blockInfo.getBlockDecl()->isConversionFromLambda();
714 llvm::Constant *blockFn
715 = CodeGenFunction(CGM, true).GenerateBlockFunction(CurGD, blockInfo,
718 blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy);
720 // If there is nothing to capture, we can emit this as a global block.
721 if (blockInfo.CanBeGlobal)
722 return buildGlobalBlock(CGM, blockInfo, blockFn);
724 // Otherwise, we have to emit this as a local block.
726 llvm::Constant *isa =
727 (!CGM.getContext().getLangOpts().OpenCL)
728 ? CGM.getNSConcreteStackBlock()
729 : CGM.getNullPointer(cast<llvm::PointerType>(
730 CGM.getNSConcreteStackBlock()->getType()),
731 QualType(getContext().VoidPtrTy));
732 isa = llvm::ConstantExpr::getBitCast(isa, VoidPtrTy);
734 // Build the block descriptor.
735 llvm::Constant *descriptor = buildBlockDescriptor(CGM, blockInfo);
737 Address blockAddr = blockInfo.LocalAddress;
738 assert(blockAddr.isValid() && "block has no address!");
740 // Compute the initial on-stack block flags.
741 BlockFlags flags = BLOCK_HAS_SIGNATURE;
742 if (blockInfo.HasCapturedVariableLayout) flags |= BLOCK_HAS_EXTENDED_LAYOUT;
743 if (blockInfo.NeedsCopyDispose) flags |= BLOCK_HAS_COPY_DISPOSE;
744 if (blockInfo.HasCXXObject) flags |= BLOCK_HAS_CXX_OBJ;
745 if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET;
748 [&](unsigned index, CharUnits offset, const Twine &name) -> Address {
749 return Builder.CreateStructGEP(blockAddr, index, offset, name);
752 [&](llvm::Value *value, unsigned index, CharUnits offset,
754 Builder.CreateStore(value, projectField(index, offset, name));
757 // Initialize the block header.
759 // We assume all the header fields are densely packed.
762 auto addHeaderField =
763 [&](llvm::Value *value, CharUnits size, const Twine &name) {
764 storeField(value, index, offset, name);
769 addHeaderField(isa, getPointerSize(), "block.isa");
770 addHeaderField(llvm::ConstantInt::get(IntTy, flags.getBitMask()),
771 getIntSize(), "block.flags");
772 addHeaderField(llvm::ConstantInt::get(IntTy, 0),
773 getIntSize(), "block.reserved");
774 addHeaderField(blockFn, getPointerSize(), "block.invoke");
775 addHeaderField(descriptor, getPointerSize(), "block.descriptor");
778 // Finally, capture all the values into the block.
779 const BlockDecl *blockDecl = blockInfo.getBlockDecl();
782 if (blockDecl->capturesCXXThis()) {
783 Address addr = projectField(blockInfo.CXXThisIndex, blockInfo.CXXThisOffset,
784 "block.captured-this.addr");
785 Builder.CreateStore(LoadCXXThis(), addr);
788 // Next, captured variables.
789 for (const auto &CI : blockDecl->captures()) {
790 const VarDecl *variable = CI.getVariable();
791 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
793 // Ignore constant captures.
794 if (capture.isConstant()) continue;
796 QualType type = capture.fieldType();
798 // This will be a [[type]]*, except that a byref entry will just be
801 projectField(capture.getIndex(), capture.getOffset(), "block.captured");
803 // Compute the address of the thing we're going to move into the
805 Address src = Address::invalid();
807 if (blockDecl->isConversionFromLambda()) {
808 // The lambda capture in a lambda's conversion-to-block-pointer is
809 // special; we'll simply emit it directly.
810 src = Address::invalid();
811 } else if (CI.isByRef()) {
812 if (BlockInfo && CI.isNested()) {
813 // We need to use the capture from the enclosing block.
814 const CGBlockInfo::Capture &enclosingCapture =
815 BlockInfo->getCapture(variable);
817 // This is a [[type]]*, except that a byref entry wil just be an i8**.
818 src = Builder.CreateStructGEP(LoadBlockStruct(),
819 enclosingCapture.getIndex(),
820 enclosingCapture.getOffset(),
821 "block.capture.addr");
823 auto I = LocalDeclMap.find(variable);
824 assert(I != LocalDeclMap.end());
828 DeclRefExpr declRef(const_cast<VarDecl *>(variable),
829 /*RefersToEnclosingVariableOrCapture*/ CI.isNested(),
830 type.getNonReferenceType(), VK_LValue,
832 src = EmitDeclRefLValue(&declRef).getAddress();
835 // For byrefs, we just write the pointer to the byref struct into
836 // the block field. There's no need to chase the forwarding
837 // pointer at this point, since we're building something that will
838 // live a shorter life than the stack byref anyway.
840 // Get a void* that points to the byref struct.
841 llvm::Value *byrefPointer;
843 byrefPointer = Builder.CreateLoad(src, "byref.capture");
845 byrefPointer = Builder.CreateBitCast(src.getPointer(), VoidPtrTy);
847 // Write that void* into the capture field.
848 Builder.CreateStore(byrefPointer, blockField);
850 // If we have a copy constructor, evaluate that into the block field.
851 } else if (const Expr *copyExpr = CI.getCopyExpr()) {
852 if (blockDecl->isConversionFromLambda()) {
853 // If we have a lambda conversion, emit the expression
854 // directly into the block instead.
856 AggValueSlot::forAddr(blockField, Qualifiers(),
857 AggValueSlot::IsDestructed,
858 AggValueSlot::DoesNotNeedGCBarriers,
859 AggValueSlot::IsNotAliased);
860 EmitAggExpr(copyExpr, Slot);
862 EmitSynthesizedCXXCopyCtor(blockField, src, copyExpr);
865 // If it's a reference variable, copy the reference into the block field.
866 } else if (type->isReferenceType()) {
867 Builder.CreateStore(src.getPointer(), blockField);
869 // If this is an ARC __strong block-pointer variable, don't do a
872 // TODO: this can be generalized into the normal initialization logic:
873 // we should never need to do a block-copy when initializing a local
874 // variable, because the local variable's lifetime should be strictly
875 // contained within the stack block's.
876 } else if (type.getObjCLifetime() == Qualifiers::OCL_Strong &&
877 type->isBlockPointerType()) {
878 // Load the block and do a simple retain.
879 llvm::Value *value = Builder.CreateLoad(src, "block.captured_block");
880 value = EmitARCRetainNonBlock(value);
882 // Do a primitive store to the block field.
883 Builder.CreateStore(value, blockField);
885 // Otherwise, fake up a POD copy into the block field.
887 // Fake up a new variable so that EmitScalarInit doesn't think
888 // we're referring to the variable in its own initializer.
889 ImplicitParamDecl blockFieldPseudoVar(getContext(), /*DC*/ nullptr,
890 SourceLocation(), /*name*/ nullptr,
893 // We use one of these or the other depending on whether the
894 // reference is nested.
895 DeclRefExpr declRef(const_cast<VarDecl *>(variable),
896 /*RefersToEnclosingVariableOrCapture*/ CI.isNested(),
897 type, VK_LValue, SourceLocation());
899 ImplicitCastExpr l2r(ImplicitCastExpr::OnStack, type, CK_LValueToRValue,
900 &declRef, VK_RValue);
901 // FIXME: Pass a specific location for the expr init so that the store is
902 // attributed to a reasonable location - otherwise it may be attributed to
903 // locations of subexpressions in the initialization.
904 EmitExprAsInit(&l2r, &blockFieldPseudoVar,
905 MakeAddrLValue(blockField, type, AlignmentSource::Decl),
906 /*captured by init*/ false);
909 // Activate the cleanup if layout pushed one.
911 EHScopeStack::stable_iterator cleanup = capture.getCleanup();
912 if (cleanup.isValid())
913 ActivateCleanupBlock(cleanup, blockInfo.DominatingIP);
917 // Cast to the converted block-pointer type, which happens (somewhat
918 // unfortunately) to be a pointer to function type.
919 llvm::Value *result = Builder.CreatePointerCast(
920 blockAddr.getPointer(), ConvertType(blockInfo.getBlockExpr()->getType()));
926 llvm::Type *CodeGenModule::getBlockDescriptorType() {
927 if (BlockDescriptorType)
928 return BlockDescriptorType;
930 llvm::Type *UnsignedLongTy =
931 getTypes().ConvertType(getContext().UnsignedLongTy);
933 // struct __block_descriptor {
934 // unsigned long reserved;
935 // unsigned long block_size;
937 // // later, the following will be added
940 // void (*copyHelper)();
941 // void (*copyHelper)();
942 // } helpers; // !!! optional
944 // const char *signature; // the block signature
945 // const char *layout; // reserved
947 BlockDescriptorType =
948 llvm::StructType::create("struct.__block_descriptor",
949 UnsignedLongTy, UnsignedLongTy, nullptr);
951 // Now form a pointer to that.
952 unsigned AddrSpace = 0;
953 if (getLangOpts().OpenCL)
954 AddrSpace = getContext().getTargetAddressSpace(LangAS::opencl_constant);
955 BlockDescriptorType = llvm::PointerType::get(BlockDescriptorType, AddrSpace);
956 return BlockDescriptorType;
959 llvm::Type *CodeGenModule::getGenericBlockLiteralType() {
960 if (GenericBlockLiteralType)
961 return GenericBlockLiteralType;
963 llvm::Type *BlockDescPtrTy = getBlockDescriptorType();
965 // struct __block_literal_generic {
969 // void (*__invoke)(void *);
970 // struct __block_descriptor *__descriptor;
972 GenericBlockLiteralType =
973 llvm::StructType::create("struct.__block_literal_generic",
974 VoidPtrTy, IntTy, IntTy, VoidPtrTy,
975 BlockDescPtrTy, nullptr);
977 return GenericBlockLiteralType;
980 RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr *E,
981 ReturnValueSlot ReturnValue) {
982 const BlockPointerType *BPT =
983 E->getCallee()->getType()->getAs<BlockPointerType>();
985 llvm::Value *BlockPtr = EmitScalarExpr(E->getCallee());
987 // Get a pointer to the generic block literal.
988 // For OpenCL we generate generic AS void ptr to be able to reuse the same
989 // block definition for blocks with captures generated as private AS local
990 // variables and without captures generated as global AS program scope
992 unsigned AddrSpace = 0;
993 if (getLangOpts().OpenCL)
994 AddrSpace = getContext().getTargetAddressSpace(LangAS::opencl_generic);
996 llvm::Type *BlockLiteralTy =
997 llvm::PointerType::get(CGM.getGenericBlockLiteralType(), AddrSpace);
999 // Bitcast the callee to a block literal.
1001 Builder.CreatePointerCast(BlockPtr, BlockLiteralTy, "block.literal");
1003 // Get the function pointer from the literal.
1004 llvm::Value *FuncPtr =
1005 Builder.CreateStructGEP(CGM.getGenericBlockLiteralType(), BlockPtr, 3);
1008 // Add the block literal.
1011 QualType VoidPtrQualTy = getContext().VoidPtrTy;
1012 llvm::Type *GenericVoidPtrTy = VoidPtrTy;
1013 if (getLangOpts().OpenCL) {
1014 GenericVoidPtrTy = Builder.getInt8PtrTy(
1015 getContext().getTargetAddressSpace(LangAS::opencl_generic));
1017 getContext().getPointerType(getContext().getAddrSpaceQualType(
1018 getContext().VoidTy, LangAS::opencl_generic));
1021 BlockPtr = Builder.CreatePointerCast(BlockPtr, GenericVoidPtrTy);
1022 Args.add(RValue::get(BlockPtr), VoidPtrQualTy);
1024 QualType FnType = BPT->getPointeeType();
1026 // And the rest of the arguments.
1027 EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(), E->arguments());
1029 // Load the function.
1030 llvm::Value *Func = Builder.CreateAlignedLoad(FuncPtr, getPointerAlign());
1032 const FunctionType *FuncTy = FnType->castAs<FunctionType>();
1033 const CGFunctionInfo &FnInfo =
1034 CGM.getTypes().arrangeBlockFunctionCall(Args, FuncTy);
1036 // Cast the function pointer to the right type.
1037 llvm::Type *BlockFTy = CGM.getTypes().GetFunctionType(FnInfo);
1039 llvm::Type *BlockFTyPtr = llvm::PointerType::getUnqual(BlockFTy);
1040 Func = Builder.CreateBitCast(Func, BlockFTyPtr);
1042 // Prepare the callee.
1043 CGCallee Callee(CGCalleeInfo(), Func);
1045 // And call the block.
1046 return EmitCall(FnInfo, Callee, ReturnValue, Args);
1049 Address CodeGenFunction::GetAddrOfBlockDecl(const VarDecl *variable,
1051 assert(BlockInfo && "evaluating block ref without block information?");
1052 const CGBlockInfo::Capture &capture = BlockInfo->getCapture(variable);
1054 // Handle constant captures.
1055 if (capture.isConstant()) return LocalDeclMap.find(variable)->second;
1058 Builder.CreateStructGEP(LoadBlockStruct(), capture.getIndex(),
1059 capture.getOffset(), "block.capture.addr");
1062 // addr should be a void** right now. Load, then cast the result
1065 auto &byrefInfo = getBlockByrefInfo(variable);
1066 addr = Address(Builder.CreateLoad(addr), byrefInfo.ByrefAlignment);
1068 auto byrefPointerType = llvm::PointerType::get(byrefInfo.Type, 0);
1069 addr = Builder.CreateBitCast(addr, byrefPointerType, "byref.addr");
1071 addr = emitBlockByrefAddress(addr, byrefInfo, /*follow*/ true,
1072 variable->getName());
1075 if (auto refType = capture.fieldType()->getAs<ReferenceType>())
1076 addr = EmitLoadOfReference(addr, refType);
1081 void CodeGenModule::setAddrOfGlobalBlock(const BlockExpr *BE,
1082 llvm::Constant *Addr) {
1083 bool Ok = EmittedGlobalBlocks.insert(std::make_pair(BE, Addr)).second;
1085 assert(Ok && "Trying to replace an already-existing global block!");
1089 CodeGenModule::GetAddrOfGlobalBlock(const BlockExpr *BE,
1091 if (llvm::Constant *Block = getAddrOfGlobalBlockIfEmitted(BE))
1094 CGBlockInfo blockInfo(BE->getBlockDecl(), Name);
1095 blockInfo.BlockExpression = BE;
1097 // Compute information about the layout, etc., of this block.
1098 computeBlockInfo(*this, nullptr, blockInfo);
1100 // Using that metadata, generate the actual block function.
1101 llvm::Constant *blockFn;
1103 CodeGenFunction::DeclMapTy LocalDeclMap;
1104 blockFn = CodeGenFunction(*this).GenerateBlockFunction(GlobalDecl(),
1109 blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy);
1111 return buildGlobalBlock(*this, blockInfo, blockFn);
1114 static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
1115 const CGBlockInfo &blockInfo,
1116 llvm::Constant *blockFn) {
1117 assert(blockInfo.CanBeGlobal);
1118 // Callers should detect this case on their own: calling this function
1119 // generally requires computing layout information, which is a waste of time
1120 // if we've already emitted this block.
1121 assert(!CGM.getAddrOfGlobalBlockIfEmitted(blockInfo.BlockExpression) &&
1122 "Refusing to re-emit a global block.");
1124 // Generate the constants for the block literal initializer.
1125 ConstantInitBuilder builder(CGM);
1126 auto fields = builder.beginStruct();
1130 (!CGM.getContext().getLangOpts().OpenCL)
1131 ? CGM.getNSConcreteGlobalBlock()
1132 : CGM.getNullPointer(cast<llvm::PointerType>(
1133 CGM.getNSConcreteGlobalBlock()->getType()),
1134 QualType(CGM.getContext().VoidPtrTy)));
1137 BlockFlags flags = BLOCK_IS_GLOBAL | BLOCK_HAS_SIGNATURE;
1138 if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET;
1140 fields.addInt(CGM.IntTy, flags.getBitMask());
1143 fields.addInt(CGM.IntTy, 0);
1146 fields.add(blockFn);
1149 fields.add(buildBlockDescriptor(CGM, blockInfo));
1151 unsigned AddrSpace = 0;
1152 if (CGM.getContext().getLangOpts().OpenCL)
1153 AddrSpace = CGM.getContext().getTargetAddressSpace(LangAS::opencl_global);
1155 llvm::Constant *literal = fields.finishAndCreateGlobal(
1156 "__block_literal_global", blockInfo.BlockAlign,
1157 /*constant*/ true, llvm::GlobalVariable::InternalLinkage, AddrSpace);
1159 // Return a constant of the appropriately-casted type.
1160 llvm::Type *RequiredType =
1161 CGM.getTypes().ConvertType(blockInfo.getBlockExpr()->getType());
1162 llvm::Constant *Result =
1163 llvm::ConstantExpr::getPointerCast(literal, RequiredType);
1164 CGM.setAddrOfGlobalBlock(blockInfo.BlockExpression, Result);
1168 void CodeGenFunction::setBlockContextParameter(const ImplicitParamDecl *D,
1171 assert(BlockInfo && "not emitting prologue of block invocation function?!");
1173 llvm::Value *localAddr = nullptr;
1174 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1175 // Allocate a stack slot to let the debug info survive the RA.
1176 Address alloc = CreateMemTemp(D->getType(), D->getName() + ".addr");
1177 Builder.CreateStore(arg, alloc);
1178 localAddr = Builder.CreateLoad(alloc);
1181 if (CGDebugInfo *DI = getDebugInfo()) {
1182 if (CGM.getCodeGenOpts().getDebugInfo() >=
1183 codegenoptions::LimitedDebugInfo) {
1184 DI->setLocation(D->getLocation());
1185 DI->EmitDeclareOfBlockLiteralArgVariable(*BlockInfo, arg, argNum,
1186 localAddr, Builder);
1190 SourceLocation StartLoc = BlockInfo->getBlockExpr()->getBody()->getLocStart();
1191 ApplyDebugLocation Scope(*this, StartLoc);
1193 // Instead of messing around with LocalDeclMap, just set the value
1194 // directly as BlockPointer.
1195 BlockPointer = Builder.CreatePointerCast(
1197 BlockInfo->StructureType->getPointerTo(
1198 getContext().getLangOpts().OpenCL
1199 ? getContext().getTargetAddressSpace(LangAS::opencl_generic)
1204 Address CodeGenFunction::LoadBlockStruct() {
1205 assert(BlockInfo && "not in a block invocation function!");
1206 assert(BlockPointer && "no block pointer set!");
1207 return Address(BlockPointer, BlockInfo->BlockAlign);
1211 CodeGenFunction::GenerateBlockFunction(GlobalDecl GD,
1212 const CGBlockInfo &blockInfo,
1213 const DeclMapTy &ldm,
1214 bool IsLambdaConversionToBlock) {
1215 const BlockDecl *blockDecl = blockInfo.getBlockDecl();
1219 CurEHLocation = blockInfo.getBlockExpr()->getLocEnd();
1221 BlockInfo = &blockInfo;
1223 // Arrange for local static and local extern declarations to appear
1224 // to be local to this function as well, in case they're directly
1225 // referenced in a block.
1226 for (DeclMapTy::const_iterator i = ldm.begin(), e = ldm.end(); i != e; ++i) {
1227 const auto *var = dyn_cast<VarDecl>(i->first);
1228 if (var && !var->hasLocalStorage())
1229 setAddrOfLocalVar(var, i->second);
1232 // Begin building the function declaration.
1234 // Build the argument list.
1235 FunctionArgList args;
1237 // The first argument is the block pointer. Just take it as a void*
1238 // and cast it later.
1239 QualType selfTy = getContext().VoidPtrTy;
1241 // For OpenCL passed block pointer can be private AS local variable or
1242 // global AS program scope variable (for the case with and without captures).
1243 // Generic AS is used therefore to be able to accomodate both private and
1244 // generic AS in one implementation.
1245 if (getLangOpts().OpenCL)
1246 selfTy = getContext().getPointerType(getContext().getAddrSpaceQualType(
1247 getContext().VoidTy, LangAS::opencl_generic));
1249 IdentifierInfo *II = &CGM.getContext().Idents.get(".block_descriptor");
1251 ImplicitParamDecl selfDecl(getContext(), const_cast<BlockDecl*>(blockDecl),
1252 SourceLocation(), II, selfTy);
1253 args.push_back(&selfDecl);
1255 // Now add the rest of the parameters.
1256 args.append(blockDecl->param_begin(), blockDecl->param_end());
1258 // Create the function declaration.
1259 const FunctionProtoType *fnType = blockInfo.getBlockExpr()->getFunctionType();
1260 const CGFunctionInfo &fnInfo =
1261 CGM.getTypes().arrangeBlockFunctionDeclaration(fnType, args);
1262 if (CGM.ReturnSlotInterferesWithArgs(fnInfo))
1263 blockInfo.UsesStret = true;
1265 llvm::FunctionType *fnLLVMType = CGM.getTypes().GetFunctionType(fnInfo);
1267 StringRef name = CGM.getBlockMangledName(GD, blockDecl);
1268 llvm::Function *fn = llvm::Function::Create(
1269 fnLLVMType, llvm::GlobalValue::InternalLinkage, name, &CGM.getModule());
1270 CGM.SetInternalFunctionAttributes(blockDecl, fn, fnInfo);
1272 // Begin generating the function.
1273 StartFunction(blockDecl, fnType->getReturnType(), fn, fnInfo, args,
1274 blockDecl->getLocation(),
1275 blockInfo.getBlockExpr()->getBody()->getLocStart());
1277 // Okay. Undo some of what StartFunction did.
1279 // At -O0 we generate an explicit alloca for the BlockPointer, so the RA
1280 // won't delete the dbg.declare intrinsics for captured variables.
1281 llvm::Value *BlockPointerDbgLoc = BlockPointer;
1282 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1283 // Allocate a stack slot for it, so we can point the debugger to it
1284 Address Alloca = CreateTempAlloca(BlockPointer->getType(),
1287 // Set the DebugLocation to empty, so the store is recognized as a
1288 // frame setup instruction by llvm::DwarfDebug::beginFunction().
1289 auto NL = ApplyDebugLocation::CreateEmpty(*this);
1290 Builder.CreateStore(BlockPointer, Alloca);
1291 BlockPointerDbgLoc = Alloca.getPointer();
1294 // If we have a C++ 'this' reference, go ahead and force it into
1296 if (blockDecl->capturesCXXThis()) {
1298 Builder.CreateStructGEP(LoadBlockStruct(), blockInfo.CXXThisIndex,
1299 blockInfo.CXXThisOffset, "block.captured-this");
1300 CXXThisValue = Builder.CreateLoad(addr, "this");
1303 // Also force all the constant captures.
1304 for (const auto &CI : blockDecl->captures()) {
1305 const VarDecl *variable = CI.getVariable();
1306 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
1307 if (!capture.isConstant()) continue;
1309 CharUnits align = getContext().getDeclAlign(variable);
1311 CreateMemTemp(variable->getType(), align, "block.captured-const");
1313 Builder.CreateStore(capture.getConstant(), alloca);
1315 setAddrOfLocalVar(variable, alloca);
1318 // Save a spot to insert the debug information for all the DeclRefExprs.
1319 llvm::BasicBlock *entry = Builder.GetInsertBlock();
1320 llvm::BasicBlock::iterator entry_ptr = Builder.GetInsertPoint();
1323 if (IsLambdaConversionToBlock)
1324 EmitLambdaBlockInvokeBody();
1326 PGO.assignRegionCounters(GlobalDecl(blockDecl), fn);
1327 incrementProfileCounter(blockDecl->getBody());
1328 EmitStmt(blockDecl->getBody());
1331 // Remember where we were...
1332 llvm::BasicBlock *resume = Builder.GetInsertBlock();
1334 // Go back to the entry.
1336 Builder.SetInsertPoint(entry, entry_ptr);
1338 // Emit debug information for all the DeclRefExprs.
1339 // FIXME: also for 'this'
1340 if (CGDebugInfo *DI = getDebugInfo()) {
1341 for (const auto &CI : blockDecl->captures()) {
1342 const VarDecl *variable = CI.getVariable();
1343 DI->EmitLocation(Builder, variable->getLocation());
1345 if (CGM.getCodeGenOpts().getDebugInfo() >=
1346 codegenoptions::LimitedDebugInfo) {
1347 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
1348 if (capture.isConstant()) {
1349 auto addr = LocalDeclMap.find(variable)->second;
1350 DI->EmitDeclareOfAutoVariable(variable, addr.getPointer(),
1355 DI->EmitDeclareOfBlockDeclRefVariable(
1356 variable, BlockPointerDbgLoc, Builder, blockInfo,
1357 entry_ptr == entry->end() ? nullptr : &*entry_ptr);
1360 // Recover location if it was changed in the above loop.
1361 DI->EmitLocation(Builder,
1362 cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc());
1365 // And resume where we left off.
1366 if (resume == nullptr)
1367 Builder.ClearInsertionPoint();
1369 Builder.SetInsertPoint(resume);
1371 FinishFunction(cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc());
1378 /// Represents a type of copy/destroy operation that should be performed for an
1379 /// entity that's captured by a block.
1380 enum class BlockCaptureEntityKind {
1381 CXXRecord, // Copy or destroy
1384 BlockObject, // Assign or release
1388 /// Represents a captured entity that requires extra operations in order for
1389 /// this entity to be copied or destroyed correctly.
1390 struct BlockCaptureManagedEntity {
1391 BlockCaptureEntityKind Kind;
1392 BlockFieldFlags Flags;
1393 const BlockDecl::Capture &CI;
1394 const CGBlockInfo::Capture &Capture;
1396 BlockCaptureManagedEntity(BlockCaptureEntityKind Type, BlockFieldFlags Flags,
1397 const BlockDecl::Capture &CI,
1398 const CGBlockInfo::Capture &Capture)
1399 : Kind(Type), Flags(Flags), CI(CI), Capture(Capture) {}
1402 } // end anonymous namespace
1404 static std::pair<BlockCaptureEntityKind, BlockFieldFlags>
1405 computeCopyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T,
1406 const LangOptions &LangOpts) {
1407 if (CI.getCopyExpr()) {
1408 assert(!CI.isByRef());
1409 // don't bother computing flags
1410 return std::make_pair(BlockCaptureEntityKind::CXXRecord, BlockFieldFlags());
1412 BlockFieldFlags Flags;
1414 Flags = BLOCK_FIELD_IS_BYREF;
1415 if (T.isObjCGCWeak())
1416 Flags |= BLOCK_FIELD_IS_WEAK;
1417 return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags);
1419 if (!T->isObjCRetainableType())
1420 // For all other types, the memcpy is fine.
1421 return std::make_pair(BlockCaptureEntityKind::None, Flags);
1423 Flags = BLOCK_FIELD_IS_OBJECT;
1424 bool isBlockPointer = T->isBlockPointerType();
1426 Flags = BLOCK_FIELD_IS_BLOCK;
1428 // Special rules for ARC captures:
1429 Qualifiers QS = T.getQualifiers();
1431 // We need to register __weak direct captures with the runtime.
1432 if (QS.getObjCLifetime() == Qualifiers::OCL_Weak)
1433 return std::make_pair(BlockCaptureEntityKind::ARCWeak, Flags);
1435 // We need to retain the copied value for __strong direct captures.
1436 if (QS.getObjCLifetime() == Qualifiers::OCL_Strong) {
1437 // If it's a block pointer, we have to copy the block and
1438 // assign that to the destination pointer, so we might as
1439 // well use _Block_object_assign. Otherwise we can avoid that.
1440 return std::make_pair(!isBlockPointer ? BlockCaptureEntityKind::ARCStrong
1441 : BlockCaptureEntityKind::BlockObject,
1445 // Non-ARC captures of retainable pointers are strong and
1446 // therefore require a call to _Block_object_assign.
1447 if (!QS.getObjCLifetime() && !LangOpts.ObjCAutoRefCount)
1448 return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags);
1450 // Otherwise the memcpy is fine.
1451 return std::make_pair(BlockCaptureEntityKind::None, Flags);
1454 /// Find the set of block captures that need to be explicitly copied or destroy.
1455 static void findBlockCapturedManagedEntities(
1456 const CGBlockInfo &BlockInfo, const LangOptions &LangOpts,
1457 SmallVectorImpl<BlockCaptureManagedEntity> &ManagedCaptures,
1458 llvm::function_ref<std::pair<BlockCaptureEntityKind, BlockFieldFlags>(
1459 const BlockDecl::Capture &, QualType, const LangOptions &)>
1461 for (const auto &CI : BlockInfo.getBlockDecl()->captures()) {
1462 const VarDecl *Variable = CI.getVariable();
1463 const CGBlockInfo::Capture &Capture = BlockInfo.getCapture(Variable);
1464 if (Capture.isConstant())
1467 auto Info = Predicate(CI, Variable->getType(), LangOpts);
1468 if (Info.first != BlockCaptureEntityKind::None)
1469 ManagedCaptures.emplace_back(Info.first, Info.second, CI, Capture);
1473 /// Generate the copy-helper function for a block closure object:
1474 /// static void block_copy_helper(block_t *dst, block_t *src);
1475 /// The runtime will have previously initialized 'dst' by doing a
1476 /// bit-copy of 'src'.
1478 /// Note that this copies an entire block closure object to the heap;
1479 /// it should not be confused with a 'byref copy helper', which moves
1480 /// the contents of an individual __block variable to the heap.
1482 CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) {
1483 ASTContext &C = getContext();
1485 FunctionArgList args;
1486 ImplicitParamDecl dstDecl(getContext(), nullptr, SourceLocation(), nullptr,
1488 args.push_back(&dstDecl);
1489 ImplicitParamDecl srcDecl(getContext(), nullptr, SourceLocation(), nullptr,
1491 args.push_back(&srcDecl);
1493 const CGFunctionInfo &FI =
1494 CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, args);
1496 // FIXME: it would be nice if these were mergeable with things with
1497 // identical semantics.
1498 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
1500 llvm::Function *Fn =
1501 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
1502 "__copy_helper_block_", &CGM.getModule());
1505 = &CGM.getContext().Idents.get("__copy_helper_block_");
1507 FunctionDecl *FD = FunctionDecl::Create(C,
1508 C.getTranslationUnitDecl(),
1510 SourceLocation(), II, C.VoidTy,
1515 CGM.SetInternalFunctionAttributes(nullptr, Fn, FI);
1517 auto NL = ApplyDebugLocation::CreateEmpty(*this);
1518 StartFunction(FD, C.VoidTy, Fn, FI, args);
1519 // Create a scope with an artificial location for the body of this function.
1520 auto AL = ApplyDebugLocation::CreateArtificial(*this);
1521 llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
1523 Address src = GetAddrOfLocalVar(&srcDecl);
1524 src = Address(Builder.CreateLoad(src), blockInfo.BlockAlign);
1525 src = Builder.CreateBitCast(src, structPtrTy, "block.source");
1527 Address dst = GetAddrOfLocalVar(&dstDecl);
1528 dst = Address(Builder.CreateLoad(dst), blockInfo.BlockAlign);
1529 dst = Builder.CreateBitCast(dst, structPtrTy, "block.dest");
1531 SmallVector<BlockCaptureManagedEntity, 4> CopiedCaptures;
1532 findBlockCapturedManagedEntities(blockInfo, getLangOpts(), CopiedCaptures,
1533 computeCopyInfoForBlockCapture);
1535 for (const auto &CopiedCapture : CopiedCaptures) {
1536 const BlockDecl::Capture &CI = CopiedCapture.CI;
1537 const CGBlockInfo::Capture &capture = CopiedCapture.Capture;
1538 BlockFieldFlags flags = CopiedCapture.Flags;
1540 unsigned index = capture.getIndex();
1541 Address srcField = Builder.CreateStructGEP(src, index, capture.getOffset());
1542 Address dstField = Builder.CreateStructGEP(dst, index, capture.getOffset());
1544 // If there's an explicit copy expression, we do that.
1545 if (CI.getCopyExpr()) {
1546 assert(CopiedCapture.Kind == BlockCaptureEntityKind::CXXRecord);
1547 EmitSynthesizedCXXCopyCtor(dstField, srcField, CI.getCopyExpr());
1548 } else if (CopiedCapture.Kind == BlockCaptureEntityKind::ARCWeak) {
1549 EmitARCCopyWeak(dstField, srcField);
1551 llvm::Value *srcValue = Builder.CreateLoad(srcField, "blockcopy.src");
1552 if (CopiedCapture.Kind == BlockCaptureEntityKind::ARCStrong) {
1553 // At -O0, store null into the destination field (so that the
1554 // storeStrong doesn't over-release) and then call storeStrong.
1555 // This is a workaround to not having an initStrong call.
1556 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1557 auto *ty = cast<llvm::PointerType>(srcValue->getType());
1558 llvm::Value *null = llvm::ConstantPointerNull::get(ty);
1559 Builder.CreateStore(null, dstField);
1560 EmitARCStoreStrongCall(dstField, srcValue, true);
1562 // With optimization enabled, take advantage of the fact that
1563 // the blocks runtime guarantees a memcpy of the block data, and
1564 // just emit a retain of the src field.
1566 EmitARCRetainNonBlock(srcValue);
1568 // We don't need this anymore, so kill it. It's not quite
1569 // worth the annoyance to avoid creating it in the first place.
1570 cast<llvm::Instruction>(dstField.getPointer())->eraseFromParent();
1573 assert(CopiedCapture.Kind == BlockCaptureEntityKind::BlockObject);
1574 srcValue = Builder.CreateBitCast(srcValue, VoidPtrTy);
1575 llvm::Value *dstAddr =
1576 Builder.CreateBitCast(dstField.getPointer(), VoidPtrTy);
1577 llvm::Value *args[] = {
1578 dstAddr, srcValue, llvm::ConstantInt::get(Int32Ty, flags.getBitMask())
1581 const VarDecl *variable = CI.getVariable();
1582 bool copyCanThrow = false;
1583 if (CI.isByRef() && variable->getType()->getAsCXXRecordDecl()) {
1584 const Expr *copyExpr =
1585 CGM.getContext().getBlockVarCopyInits(variable);
1587 copyCanThrow = true; // FIXME: reuse the noexcept logic
1592 EmitRuntimeCallOrInvoke(CGM.getBlockObjectAssign(), args);
1594 EmitNounwindRuntimeCall(CGM.getBlockObjectAssign(), args);
1602 return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
1605 static std::pair<BlockCaptureEntityKind, BlockFieldFlags>
1606 computeDestroyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T,
1607 const LangOptions &LangOpts) {
1608 BlockFieldFlags Flags;
1610 Flags = BLOCK_FIELD_IS_BYREF;
1611 if (T.isObjCGCWeak())
1612 Flags |= BLOCK_FIELD_IS_WEAK;
1613 return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags);
1616 if (const CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
1617 if (Record->hasTrivialDestructor())
1618 return std::make_pair(BlockCaptureEntityKind::None, BlockFieldFlags());
1619 return std::make_pair(BlockCaptureEntityKind::CXXRecord, BlockFieldFlags());
1622 // Other types don't need to be destroy explicitly.
1623 if (!T->isObjCRetainableType())
1624 return std::make_pair(BlockCaptureEntityKind::None, Flags);
1626 Flags = BLOCK_FIELD_IS_OBJECT;
1627 if (T->isBlockPointerType())
1628 Flags = BLOCK_FIELD_IS_BLOCK;
1630 // Special rules for ARC captures.
1631 Qualifiers QS = T.getQualifiers();
1633 // Use objc_storeStrong for __strong direct captures; the
1634 // dynamic tools really like it when we do this.
1635 if (QS.getObjCLifetime() == Qualifiers::OCL_Strong)
1636 return std::make_pair(BlockCaptureEntityKind::ARCStrong, Flags);
1638 // Support __weak direct captures.
1639 if (QS.getObjCLifetime() == Qualifiers::OCL_Weak)
1640 return std::make_pair(BlockCaptureEntityKind::ARCWeak, Flags);
1642 // Non-ARC captures are strong, and we need to use
1643 // _Block_object_dispose.
1644 if (!QS.hasObjCLifetime() && !LangOpts.ObjCAutoRefCount)
1645 return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags);
1647 // Otherwise, we have nothing to do.
1648 return std::make_pair(BlockCaptureEntityKind::None, Flags);
1651 /// Generate the destroy-helper function for a block closure object:
1652 /// static void block_destroy_helper(block_t *theBlock);
1654 /// Note that this destroys a heap-allocated block closure object;
1655 /// it should not be confused with a 'byref destroy helper', which
1656 /// destroys the heap-allocated contents of an individual __block
1659 CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) {
1660 ASTContext &C = getContext();
1662 FunctionArgList args;
1663 ImplicitParamDecl srcDecl(getContext(), nullptr, SourceLocation(), nullptr,
1665 args.push_back(&srcDecl);
1667 const CGFunctionInfo &FI =
1668 CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, args);
1670 // FIXME: We'd like to put these into a mergable by content, with
1671 // internal linkage.
1672 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
1674 llvm::Function *Fn =
1675 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
1676 "__destroy_helper_block_", &CGM.getModule());
1679 = &CGM.getContext().Idents.get("__destroy_helper_block_");
1681 FunctionDecl *FD = FunctionDecl::Create(C, C.getTranslationUnitDecl(),
1683 SourceLocation(), II, C.VoidTy,
1687 CGM.SetInternalFunctionAttributes(nullptr, Fn, FI);
1689 // Create a scope with an artificial location for the body of this function.
1690 auto NL = ApplyDebugLocation::CreateEmpty(*this);
1691 StartFunction(FD, C.VoidTy, Fn, FI, args);
1692 auto AL = ApplyDebugLocation::CreateArtificial(*this);
1694 llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
1696 Address src = GetAddrOfLocalVar(&srcDecl);
1697 src = Address(Builder.CreateLoad(src), blockInfo.BlockAlign);
1698 src = Builder.CreateBitCast(src, structPtrTy, "block");
1700 CodeGenFunction::RunCleanupsScope cleanups(*this);
1702 SmallVector<BlockCaptureManagedEntity, 4> DestroyedCaptures;
1703 findBlockCapturedManagedEntities(blockInfo, getLangOpts(), DestroyedCaptures,
1704 computeDestroyInfoForBlockCapture);
1706 for (const auto &DestroyedCapture : DestroyedCaptures) {
1707 const BlockDecl::Capture &CI = DestroyedCapture.CI;
1708 const CGBlockInfo::Capture &capture = DestroyedCapture.Capture;
1709 BlockFieldFlags flags = DestroyedCapture.Flags;
1712 Builder.CreateStructGEP(src, capture.getIndex(), capture.getOffset());
1714 // If the captured record has a destructor then call it.
1715 if (DestroyedCapture.Kind == BlockCaptureEntityKind::CXXRecord) {
1717 CI.getVariable()->getType()->getAsCXXRecordDecl()->getDestructor();
1718 PushDestructorCleanup(Dtor, srcField);
1720 // If this is a __weak capture, emit the release directly.
1721 } else if (DestroyedCapture.Kind == BlockCaptureEntityKind::ARCWeak) {
1722 EmitARCDestroyWeak(srcField);
1724 // Destroy strong objects with a call if requested.
1725 } else if (DestroyedCapture.Kind == BlockCaptureEntityKind::ARCStrong) {
1726 EmitARCDestroyStrong(srcField, ARCImpreciseLifetime);
1728 // Otherwise we call _Block_object_dispose. It wouldn't be too
1729 // hard to just emit this as a cleanup if we wanted to make sure
1730 // that things were done in reverse.
1732 assert(DestroyedCapture.Kind == BlockCaptureEntityKind::BlockObject);
1733 llvm::Value *value = Builder.CreateLoad(srcField);
1734 value = Builder.CreateBitCast(value, VoidPtrTy);
1735 BuildBlockRelease(value, flags);
1739 cleanups.ForceCleanup();
1743 return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
1748 /// Emits the copy/dispose helper functions for a __block object of id type.
1749 class ObjectByrefHelpers final : public BlockByrefHelpers {
1750 BlockFieldFlags Flags;
1753 ObjectByrefHelpers(CharUnits alignment, BlockFieldFlags flags)
1754 : BlockByrefHelpers(alignment), Flags(flags) {}
1756 void emitCopy(CodeGenFunction &CGF, Address destField,
1757 Address srcField) override {
1758 destField = CGF.Builder.CreateBitCast(destField, CGF.VoidPtrTy);
1760 srcField = CGF.Builder.CreateBitCast(srcField, CGF.VoidPtrPtrTy);
1761 llvm::Value *srcValue = CGF.Builder.CreateLoad(srcField);
1763 unsigned flags = (Flags | BLOCK_BYREF_CALLER).getBitMask();
1765 llvm::Value *flagsVal = llvm::ConstantInt::get(CGF.Int32Ty, flags);
1766 llvm::Value *fn = CGF.CGM.getBlockObjectAssign();
1768 llvm::Value *args[] = { destField.getPointer(), srcValue, flagsVal };
1769 CGF.EmitNounwindRuntimeCall(fn, args);
1772 void emitDispose(CodeGenFunction &CGF, Address field) override {
1773 field = CGF.Builder.CreateBitCast(field, CGF.Int8PtrTy->getPointerTo(0));
1774 llvm::Value *value = CGF.Builder.CreateLoad(field);
1776 CGF.BuildBlockRelease(value, Flags | BLOCK_BYREF_CALLER);
1779 void profileImpl(llvm::FoldingSetNodeID &id) const override {
1780 id.AddInteger(Flags.getBitMask());
1784 /// Emits the copy/dispose helpers for an ARC __block __weak variable.
1785 class ARCWeakByrefHelpers final : public BlockByrefHelpers {
1787 ARCWeakByrefHelpers(CharUnits alignment) : BlockByrefHelpers(alignment) {}
1789 void emitCopy(CodeGenFunction &CGF, Address destField,
1790 Address srcField) override {
1791 CGF.EmitARCMoveWeak(destField, srcField);
1794 void emitDispose(CodeGenFunction &CGF, Address field) override {
1795 CGF.EmitARCDestroyWeak(field);
1798 void profileImpl(llvm::FoldingSetNodeID &id) const override {
1799 // 0 is distinguishable from all pointers and byref flags
1804 /// Emits the copy/dispose helpers for an ARC __block __strong variable
1805 /// that's not of block-pointer type.
1806 class ARCStrongByrefHelpers final : public BlockByrefHelpers {
1808 ARCStrongByrefHelpers(CharUnits alignment) : BlockByrefHelpers(alignment) {}
1810 void emitCopy(CodeGenFunction &CGF, Address destField,
1811 Address srcField) override {
1812 // Do a "move" by copying the value and then zeroing out the old
1815 llvm::Value *value = CGF.Builder.CreateLoad(srcField);
1818 llvm::ConstantPointerNull::get(cast<llvm::PointerType>(value->getType()));
1820 if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0) {
1821 CGF.Builder.CreateStore(null, destField);
1822 CGF.EmitARCStoreStrongCall(destField, value, /*ignored*/ true);
1823 CGF.EmitARCStoreStrongCall(srcField, null, /*ignored*/ true);
1826 CGF.Builder.CreateStore(value, destField);
1827 CGF.Builder.CreateStore(null, srcField);
1830 void emitDispose(CodeGenFunction &CGF, Address field) override {
1831 CGF.EmitARCDestroyStrong(field, ARCImpreciseLifetime);
1834 void profileImpl(llvm::FoldingSetNodeID &id) const override {
1835 // 1 is distinguishable from all pointers and byref flags
1840 /// Emits the copy/dispose helpers for an ARC __block __strong
1841 /// variable that's of block-pointer type.
1842 class ARCStrongBlockByrefHelpers final : public BlockByrefHelpers {
1844 ARCStrongBlockByrefHelpers(CharUnits alignment)
1845 : BlockByrefHelpers(alignment) {}
1847 void emitCopy(CodeGenFunction &CGF, Address destField,
1848 Address srcField) override {
1849 // Do the copy with objc_retainBlock; that's all that
1850 // _Block_object_assign would do anyway, and we'd have to pass the
1851 // right arguments to make sure it doesn't get no-op'ed.
1852 llvm::Value *oldValue = CGF.Builder.CreateLoad(srcField);
1853 llvm::Value *copy = CGF.EmitARCRetainBlock(oldValue, /*mandatory*/ true);
1854 CGF.Builder.CreateStore(copy, destField);
1857 void emitDispose(CodeGenFunction &CGF, Address field) override {
1858 CGF.EmitARCDestroyStrong(field, ARCImpreciseLifetime);
1861 void profileImpl(llvm::FoldingSetNodeID &id) const override {
1862 // 2 is distinguishable from all pointers and byref flags
1867 /// Emits the copy/dispose helpers for a __block variable with a
1868 /// nontrivial copy constructor or destructor.
1869 class CXXByrefHelpers final : public BlockByrefHelpers {
1871 const Expr *CopyExpr;
1874 CXXByrefHelpers(CharUnits alignment, QualType type,
1875 const Expr *copyExpr)
1876 : BlockByrefHelpers(alignment), VarType(type), CopyExpr(copyExpr) {}
1878 bool needsCopy() const override { return CopyExpr != nullptr; }
1879 void emitCopy(CodeGenFunction &CGF, Address destField,
1880 Address srcField) override {
1881 if (!CopyExpr) return;
1882 CGF.EmitSynthesizedCXXCopyCtor(destField, srcField, CopyExpr);
1885 void emitDispose(CodeGenFunction &CGF, Address field) override {
1886 EHScopeStack::stable_iterator cleanupDepth = CGF.EHStack.stable_begin();
1887 CGF.PushDestructorCleanup(VarType, field);
1888 CGF.PopCleanupBlocks(cleanupDepth);
1891 void profileImpl(llvm::FoldingSetNodeID &id) const override {
1892 id.AddPointer(VarType.getCanonicalType().getAsOpaquePtr());
1895 } // end anonymous namespace
1897 static llvm::Constant *
1898 generateByrefCopyHelper(CodeGenFunction &CGF, const BlockByrefInfo &byrefInfo,
1899 BlockByrefHelpers &generator) {
1900 ASTContext &Context = CGF.getContext();
1902 QualType R = Context.VoidTy;
1904 FunctionArgList args;
1905 ImplicitParamDecl dst(CGF.getContext(), nullptr, SourceLocation(), nullptr,
1907 args.push_back(&dst);
1909 ImplicitParamDecl src(CGF.getContext(), nullptr, SourceLocation(), nullptr,
1911 args.push_back(&src);
1913 const CGFunctionInfo &FI =
1914 CGF.CGM.getTypes().arrangeBuiltinFunctionDeclaration(R, args);
1916 llvm::FunctionType *LTy = CGF.CGM.getTypes().GetFunctionType(FI);
1918 // FIXME: We'd like to put these into a mergable by content, with
1919 // internal linkage.
1920 llvm::Function *Fn =
1921 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
1922 "__Block_byref_object_copy_", &CGF.CGM.getModule());
1925 = &Context.Idents.get("__Block_byref_object_copy_");
1927 FunctionDecl *FD = FunctionDecl::Create(Context,
1928 Context.getTranslationUnitDecl(),
1930 SourceLocation(), II, R, nullptr,
1934 CGF.CGM.SetInternalFunctionAttributes(nullptr, Fn, FI);
1936 CGF.StartFunction(FD, R, Fn, FI, args);
1938 if (generator.needsCopy()) {
1939 llvm::Type *byrefPtrType = byrefInfo.Type->getPointerTo(0);
1942 Address destField = CGF.GetAddrOfLocalVar(&dst);
1943 destField = Address(CGF.Builder.CreateLoad(destField),
1944 byrefInfo.ByrefAlignment);
1945 destField = CGF.Builder.CreateBitCast(destField, byrefPtrType);
1946 destField = CGF.emitBlockByrefAddress(destField, byrefInfo, false,
1950 Address srcField = CGF.GetAddrOfLocalVar(&src);
1951 srcField = Address(CGF.Builder.CreateLoad(srcField),
1952 byrefInfo.ByrefAlignment);
1953 srcField = CGF.Builder.CreateBitCast(srcField, byrefPtrType);
1954 srcField = CGF.emitBlockByrefAddress(srcField, byrefInfo, false,
1957 generator.emitCopy(CGF, destField, srcField);
1960 CGF.FinishFunction();
1962 return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy);
1965 /// Build the copy helper for a __block variable.
1966 static llvm::Constant *buildByrefCopyHelper(CodeGenModule &CGM,
1967 const BlockByrefInfo &byrefInfo,
1968 BlockByrefHelpers &generator) {
1969 CodeGenFunction CGF(CGM);
1970 return generateByrefCopyHelper(CGF, byrefInfo, generator);
1973 /// Generate code for a __block variable's dispose helper.
1974 static llvm::Constant *
1975 generateByrefDisposeHelper(CodeGenFunction &CGF,
1976 const BlockByrefInfo &byrefInfo,
1977 BlockByrefHelpers &generator) {
1978 ASTContext &Context = CGF.getContext();
1979 QualType R = Context.VoidTy;
1981 FunctionArgList args;
1982 ImplicitParamDecl src(CGF.getContext(), nullptr, SourceLocation(), nullptr,
1984 args.push_back(&src);
1986 const CGFunctionInfo &FI =
1987 CGF.CGM.getTypes().arrangeBuiltinFunctionDeclaration(R, args);
1989 llvm::FunctionType *LTy = CGF.CGM.getTypes().GetFunctionType(FI);
1991 // FIXME: We'd like to put these into a mergable by content, with
1992 // internal linkage.
1993 llvm::Function *Fn =
1994 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
1995 "__Block_byref_object_dispose_",
1996 &CGF.CGM.getModule());
1999 = &Context.Idents.get("__Block_byref_object_dispose_");
2001 FunctionDecl *FD = FunctionDecl::Create(Context,
2002 Context.getTranslationUnitDecl(),
2004 SourceLocation(), II, R, nullptr,
2008 CGF.CGM.SetInternalFunctionAttributes(nullptr, Fn, FI);
2010 CGF.StartFunction(FD, R, Fn, FI, args);
2012 if (generator.needsDispose()) {
2013 Address addr = CGF.GetAddrOfLocalVar(&src);
2014 addr = Address(CGF.Builder.CreateLoad(addr), byrefInfo.ByrefAlignment);
2015 auto byrefPtrType = byrefInfo.Type->getPointerTo(0);
2016 addr = CGF.Builder.CreateBitCast(addr, byrefPtrType);
2017 addr = CGF.emitBlockByrefAddress(addr, byrefInfo, false, "object");
2019 generator.emitDispose(CGF, addr);
2022 CGF.FinishFunction();
2024 return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy);
2027 /// Build the dispose helper for a __block variable.
2028 static llvm::Constant *buildByrefDisposeHelper(CodeGenModule &CGM,
2029 const BlockByrefInfo &byrefInfo,
2030 BlockByrefHelpers &generator) {
2031 CodeGenFunction CGF(CGM);
2032 return generateByrefDisposeHelper(CGF, byrefInfo, generator);
2035 /// Lazily build the copy and dispose helpers for a __block variable
2036 /// with the given information.
2038 static T *buildByrefHelpers(CodeGenModule &CGM, const BlockByrefInfo &byrefInfo,
2040 llvm::FoldingSetNodeID id;
2041 generator.Profile(id);
2044 BlockByrefHelpers *node
2045 = CGM.ByrefHelpersCache.FindNodeOrInsertPos(id, insertPos);
2046 if (node) return static_cast<T*>(node);
2048 generator.CopyHelper = buildByrefCopyHelper(CGM, byrefInfo, generator);
2049 generator.DisposeHelper = buildByrefDisposeHelper(CGM, byrefInfo, generator);
2051 T *copy = new (CGM.getContext()) T(std::forward<T>(generator));
2052 CGM.ByrefHelpersCache.InsertNode(copy, insertPos);
2056 /// Build the copy and dispose helpers for the given __block variable
2057 /// emission. Places the helpers in the global cache. Returns null
2058 /// if no helpers are required.
2060 CodeGenFunction::buildByrefHelpers(llvm::StructType &byrefType,
2061 const AutoVarEmission &emission) {
2062 const VarDecl &var = *emission.Variable;
2063 QualType type = var.getType();
2065 auto &byrefInfo = getBlockByrefInfo(&var);
2067 // The alignment we care about for the purposes of uniquing byref
2068 // helpers is the alignment of the actual byref value field.
2069 CharUnits valueAlignment =
2070 byrefInfo.ByrefAlignment.alignmentAtOffset(byrefInfo.FieldOffset);
2072 if (const CXXRecordDecl *record = type->getAsCXXRecordDecl()) {
2073 const Expr *copyExpr = CGM.getContext().getBlockVarCopyInits(&var);
2074 if (!copyExpr && record->hasTrivialDestructor()) return nullptr;
2076 return ::buildByrefHelpers(
2077 CGM, byrefInfo, CXXByrefHelpers(valueAlignment, type, copyExpr));
2080 // Otherwise, if we don't have a retainable type, there's nothing to do.
2081 // that the runtime does extra copies.
2082 if (!type->isObjCRetainableType()) return nullptr;
2084 Qualifiers qs = type.getQualifiers();
2086 // If we have lifetime, that dominates.
2087 if (Qualifiers::ObjCLifetime lifetime = qs.getObjCLifetime()) {
2089 case Qualifiers::OCL_None: llvm_unreachable("impossible");
2091 // These are just bits as far as the runtime is concerned.
2092 case Qualifiers::OCL_ExplicitNone:
2093 case Qualifiers::OCL_Autoreleasing:
2096 // Tell the runtime that this is ARC __weak, called by the
2098 case Qualifiers::OCL_Weak:
2099 return ::buildByrefHelpers(CGM, byrefInfo,
2100 ARCWeakByrefHelpers(valueAlignment));
2102 // ARC __strong __block variables need to be retained.
2103 case Qualifiers::OCL_Strong:
2104 // Block pointers need to be copied, and there's no direct
2105 // transfer possible.
2106 if (type->isBlockPointerType()) {
2107 return ::buildByrefHelpers(CGM, byrefInfo,
2108 ARCStrongBlockByrefHelpers(valueAlignment));
2110 // Otherwise, we transfer ownership of the retain from the stack
2113 return ::buildByrefHelpers(CGM, byrefInfo,
2114 ARCStrongByrefHelpers(valueAlignment));
2117 llvm_unreachable("fell out of lifetime switch!");
2120 BlockFieldFlags flags;
2121 if (type->isBlockPointerType()) {
2122 flags |= BLOCK_FIELD_IS_BLOCK;
2123 } else if (CGM.getContext().isObjCNSObjectType(type) ||
2124 type->isObjCObjectPointerType()) {
2125 flags |= BLOCK_FIELD_IS_OBJECT;
2130 if (type.isObjCGCWeak())
2131 flags |= BLOCK_FIELD_IS_WEAK;
2133 return ::buildByrefHelpers(CGM, byrefInfo,
2134 ObjectByrefHelpers(valueAlignment, flags));
2137 Address CodeGenFunction::emitBlockByrefAddress(Address baseAddr,
2139 bool followForward) {
2140 auto &info = getBlockByrefInfo(var);
2141 return emitBlockByrefAddress(baseAddr, info, followForward, var->getName());
2144 Address CodeGenFunction::emitBlockByrefAddress(Address baseAddr,
2145 const BlockByrefInfo &info,
2147 const llvm::Twine &name) {
2148 // Chase the forwarding address if requested.
2149 if (followForward) {
2150 Address forwardingAddr =
2151 Builder.CreateStructGEP(baseAddr, 1, getPointerSize(), "forwarding");
2152 baseAddr = Address(Builder.CreateLoad(forwardingAddr), info.ByrefAlignment);
2155 return Builder.CreateStructGEP(baseAddr, info.FieldIndex,
2156 info.FieldOffset, name);
2159 /// BuildByrefInfo - This routine changes a __block variable declared as T x
2164 /// void *__forwarding;
2165 /// int32_t __flags;
2167 /// void *__copy_helper; // only if needed
2168 /// void *__destroy_helper; // only if needed
2169 /// void *__byref_variable_layout;// only if needed
2170 /// char padding[X]; // only if needed
2174 const BlockByrefInfo &CodeGenFunction::getBlockByrefInfo(const VarDecl *D) {
2175 auto it = BlockByrefInfos.find(D);
2176 if (it != BlockByrefInfos.end())
2179 llvm::StructType *byrefType =
2180 llvm::StructType::create(getLLVMContext(),
2181 "struct.__block_byref_" + D->getNameAsString());
2183 QualType Ty = D->getType();
2186 SmallVector<llvm::Type *, 8> types;
2189 types.push_back(Int8PtrTy);
2190 size += getPointerSize();
2192 // void *__forwarding;
2193 types.push_back(llvm::PointerType::getUnqual(byrefType));
2194 size += getPointerSize();
2197 types.push_back(Int32Ty);
2198 size += CharUnits::fromQuantity(4);
2201 types.push_back(Int32Ty);
2202 size += CharUnits::fromQuantity(4);
2204 // Note that this must match *exactly* the logic in buildByrefHelpers.
2205 bool hasCopyAndDispose = getContext().BlockRequiresCopying(Ty, D);
2206 if (hasCopyAndDispose) {
2207 /// void *__copy_helper;
2208 types.push_back(Int8PtrTy);
2209 size += getPointerSize();
2211 /// void *__destroy_helper;
2212 types.push_back(Int8PtrTy);
2213 size += getPointerSize();
2216 bool HasByrefExtendedLayout = false;
2217 Qualifiers::ObjCLifetime Lifetime;
2218 if (getContext().getByrefLifetime(Ty, Lifetime, HasByrefExtendedLayout) &&
2219 HasByrefExtendedLayout) {
2220 /// void *__byref_variable_layout;
2221 types.push_back(Int8PtrTy);
2222 size += CharUnits::fromQuantity(PointerSizeInBytes);
2226 llvm::Type *varTy = ConvertTypeForMem(Ty);
2228 bool packed = false;
2229 CharUnits varAlign = getContext().getDeclAlign(D);
2230 CharUnits varOffset = size.alignTo(varAlign);
2232 // We may have to insert padding.
2233 if (varOffset != size) {
2234 llvm::Type *paddingTy =
2235 llvm::ArrayType::get(Int8Ty, (varOffset - size).getQuantity());
2237 types.push_back(paddingTy);
2240 // Conversely, we might have to prevent LLVM from inserting padding.
2241 } else if (CGM.getDataLayout().getABITypeAlignment(varTy)
2242 > varAlign.getQuantity()) {
2245 types.push_back(varTy);
2247 byrefType->setBody(types, packed);
2249 BlockByrefInfo info;
2250 info.Type = byrefType;
2251 info.FieldIndex = types.size() - 1;
2252 info.FieldOffset = varOffset;
2253 info.ByrefAlignment = std::max(varAlign, getPointerAlign());
2255 auto pair = BlockByrefInfos.insert({D, info});
2256 assert(pair.second && "info was inserted recursively?");
2257 return pair.first->second;
2260 /// Initialize the structural components of a __block variable, i.e.
2261 /// everything but the actual object.
2262 void CodeGenFunction::emitByrefStructureInit(const AutoVarEmission &emission) {
2263 // Find the address of the local.
2264 Address addr = emission.Addr;
2266 // That's an alloca of the byref structure type.
2267 llvm::StructType *byrefType = cast<llvm::StructType>(
2268 cast<llvm::PointerType>(addr.getPointer()->getType())->getElementType());
2270 unsigned nextHeaderIndex = 0;
2271 CharUnits nextHeaderOffset;
2272 auto storeHeaderField = [&](llvm::Value *value, CharUnits fieldSize,
2273 const Twine &name) {
2274 auto fieldAddr = Builder.CreateStructGEP(addr, nextHeaderIndex,
2275 nextHeaderOffset, name);
2276 Builder.CreateStore(value, fieldAddr);
2279 nextHeaderOffset += fieldSize;
2282 // Build the byref helpers if necessary. This is null if we don't need any.
2283 BlockByrefHelpers *helpers = buildByrefHelpers(*byrefType, emission);
2285 const VarDecl &D = *emission.Variable;
2286 QualType type = D.getType();
2288 bool HasByrefExtendedLayout;
2289 Qualifiers::ObjCLifetime ByrefLifetime;
2290 bool ByRefHasLifetime =
2291 getContext().getByrefLifetime(type, ByrefLifetime, HasByrefExtendedLayout);
2295 // Initialize the 'isa', which is just 0 or 1.
2297 if (type.isObjCGCWeak())
2299 V = Builder.CreateIntToPtr(Builder.getInt32(isa), Int8PtrTy, "isa");
2300 storeHeaderField(V, getPointerSize(), "byref.isa");
2302 // Store the address of the variable into its own forwarding pointer.
2303 storeHeaderField(addr.getPointer(), getPointerSize(), "byref.forwarding");
2306 // c) the flags field is set to either 0 if no helper functions are
2307 // needed or BLOCK_BYREF_HAS_COPY_DISPOSE if they are,
2309 if (helpers) flags |= BLOCK_BYREF_HAS_COPY_DISPOSE;
2310 if (ByRefHasLifetime) {
2311 if (HasByrefExtendedLayout) flags |= BLOCK_BYREF_LAYOUT_EXTENDED;
2312 else switch (ByrefLifetime) {
2313 case Qualifiers::OCL_Strong:
2314 flags |= BLOCK_BYREF_LAYOUT_STRONG;
2316 case Qualifiers::OCL_Weak:
2317 flags |= BLOCK_BYREF_LAYOUT_WEAK;
2319 case Qualifiers::OCL_ExplicitNone:
2320 flags |= BLOCK_BYREF_LAYOUT_UNRETAINED;
2322 case Qualifiers::OCL_None:
2323 if (!type->isObjCObjectPointerType() && !type->isBlockPointerType())
2324 flags |= BLOCK_BYREF_LAYOUT_NON_OBJECT;
2329 if (CGM.getLangOpts().ObjCGCBitmapPrint) {
2330 printf("\n Inline flag for BYREF variable layout (%d):", flags.getBitMask());
2331 if (flags & BLOCK_BYREF_HAS_COPY_DISPOSE)
2332 printf(" BLOCK_BYREF_HAS_COPY_DISPOSE");
2333 if (flags & BLOCK_BYREF_LAYOUT_MASK) {
2334 BlockFlags ThisFlag(flags.getBitMask() & BLOCK_BYREF_LAYOUT_MASK);
2335 if (ThisFlag == BLOCK_BYREF_LAYOUT_EXTENDED)
2336 printf(" BLOCK_BYREF_LAYOUT_EXTENDED");
2337 if (ThisFlag == BLOCK_BYREF_LAYOUT_STRONG)
2338 printf(" BLOCK_BYREF_LAYOUT_STRONG");
2339 if (ThisFlag == BLOCK_BYREF_LAYOUT_WEAK)
2340 printf(" BLOCK_BYREF_LAYOUT_WEAK");
2341 if (ThisFlag == BLOCK_BYREF_LAYOUT_UNRETAINED)
2342 printf(" BLOCK_BYREF_LAYOUT_UNRETAINED");
2343 if (ThisFlag == BLOCK_BYREF_LAYOUT_NON_OBJECT)
2344 printf(" BLOCK_BYREF_LAYOUT_NON_OBJECT");
2349 storeHeaderField(llvm::ConstantInt::get(IntTy, flags.getBitMask()),
2350 getIntSize(), "byref.flags");
2352 CharUnits byrefSize = CGM.GetTargetTypeStoreSize(byrefType);
2353 V = llvm::ConstantInt::get(IntTy, byrefSize.getQuantity());
2354 storeHeaderField(V, getIntSize(), "byref.size");
2357 storeHeaderField(helpers->CopyHelper, getPointerSize(),
2358 "byref.copyHelper");
2359 storeHeaderField(helpers->DisposeHelper, getPointerSize(),
2360 "byref.disposeHelper");
2363 if (ByRefHasLifetime && HasByrefExtendedLayout) {
2364 auto layoutInfo = CGM.getObjCRuntime().BuildByrefLayout(CGM, type);
2365 storeHeaderField(layoutInfo, getPointerSize(), "byref.layout");
2369 void CodeGenFunction::BuildBlockRelease(llvm::Value *V, BlockFieldFlags flags) {
2370 llvm::Value *F = CGM.getBlockObjectDispose();
2371 llvm::Value *args[] = {
2372 Builder.CreateBitCast(V, Int8PtrTy),
2373 llvm::ConstantInt::get(Int32Ty, flags.getBitMask())
2375 EmitNounwindRuntimeCall(F, args); // FIXME: throwing destructors?
2379 /// Release a __block variable.
2380 struct CallBlockRelease final : EHScopeStack::Cleanup {
2382 CallBlockRelease(llvm::Value *Addr) : Addr(Addr) {}
2384 void Emit(CodeGenFunction &CGF, Flags flags) override {
2385 // Should we be passing FIELD_IS_WEAK here?
2386 CGF.BuildBlockRelease(Addr, BLOCK_FIELD_IS_BYREF);
2389 } // end anonymous namespace
2391 /// Enter a cleanup to destroy a __block variable. Note that this
2392 /// cleanup should be a no-op if the variable hasn't left the stack
2393 /// yet; if a cleanup is required for the variable itself, that needs
2394 /// to be done externally.
2395 void CodeGenFunction::enterByrefCleanup(const AutoVarEmission &emission) {
2396 // We don't enter this cleanup if we're in pure-GC mode.
2397 if (CGM.getLangOpts().getGC() == LangOptions::GCOnly)
2400 EHStack.pushCleanup<CallBlockRelease>(NormalAndEHCleanup,
2401 emission.Addr.getPointer());
2404 /// Adjust the declaration of something from the blocks API.
2405 static void configureBlocksRuntimeObject(CodeGenModule &CGM,
2406 llvm::Constant *C) {
2407 auto *GV = cast<llvm::GlobalValue>(C->stripPointerCasts());
2409 if (CGM.getTarget().getTriple().isOSBinFormatCOFF()) {
2410 IdentifierInfo &II = CGM.getContext().Idents.get(C->getName());
2411 TranslationUnitDecl *TUDecl = CGM.getContext().getTranslationUnitDecl();
2412 DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
2414 assert((isa<llvm::Function>(C->stripPointerCasts()) ||
2415 isa<llvm::GlobalVariable>(C->stripPointerCasts())) &&
2416 "expected Function or GlobalVariable");
2418 const NamedDecl *ND = nullptr;
2419 for (const auto &Result : DC->lookup(&II))
2420 if ((ND = dyn_cast<FunctionDecl>(Result)) ||
2421 (ND = dyn_cast<VarDecl>(Result)))
2424 // TODO: support static blocks runtime
2425 if (GV->isDeclaration() && (!ND || !ND->hasAttr<DLLExportAttr>())) {
2426 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
2427 GV->setLinkage(llvm::GlobalValue::ExternalLinkage);
2429 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
2430 GV->setLinkage(llvm::GlobalValue::ExternalLinkage);
2434 if (!CGM.getLangOpts().BlocksRuntimeOptional)
2437 if (GV->isDeclaration() && GV->hasExternalLinkage())
2438 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
2441 llvm::Constant *CodeGenModule::getBlockObjectDispose() {
2442 if (BlockObjectDispose)
2443 return BlockObjectDispose;
2445 llvm::Type *args[] = { Int8PtrTy, Int32Ty };
2446 llvm::FunctionType *fty
2447 = llvm::FunctionType::get(VoidTy, args, false);
2448 BlockObjectDispose = CreateRuntimeFunction(fty, "_Block_object_dispose");
2449 configureBlocksRuntimeObject(*this, BlockObjectDispose);
2450 return BlockObjectDispose;
2453 llvm::Constant *CodeGenModule::getBlockObjectAssign() {
2454 if (BlockObjectAssign)
2455 return BlockObjectAssign;
2457 llvm::Type *args[] = { Int8PtrTy, Int8PtrTy, Int32Ty };
2458 llvm::FunctionType *fty
2459 = llvm::FunctionType::get(VoidTy, args, false);
2460 BlockObjectAssign = CreateRuntimeFunction(fty, "_Block_object_assign");
2461 configureBlocksRuntimeObject(*this, BlockObjectAssign);
2462 return BlockObjectAssign;
2465 llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() {
2466 if (NSConcreteGlobalBlock)
2467 return NSConcreteGlobalBlock;
2469 NSConcreteGlobalBlock = GetOrCreateLLVMGlobal("_NSConcreteGlobalBlock",
2470 Int8PtrTy->getPointerTo(),
2472 configureBlocksRuntimeObject(*this, NSConcreteGlobalBlock);
2473 return NSConcreteGlobalBlock;
2476 llvm::Constant *CodeGenModule::getNSConcreteStackBlock() {
2477 if (NSConcreteStackBlock)
2478 return NSConcreteStackBlock;
2480 NSConcreteStackBlock = GetOrCreateLLVMGlobal("_NSConcreteStackBlock",
2481 Int8PtrTy->getPointerTo(),
2483 configureBlocksRuntimeObject(*this, NSConcreteStackBlock);
2484 return NSConcreteStackBlock;