1 //===--- CGBlocks.cpp - Emit LLVM Code for declarations -------------------===//
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/AST/DeclObjC.h"
20 #include "llvm/ADT/SmallSet.h"
21 #include "llvm/IR/DataLayout.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/Support/CallSite.h"
27 using namespace clang;
28 using namespace CodeGen;
30 CGBlockInfo::CGBlockInfo(const BlockDecl *block, StringRef name)
31 : Name(name), CXXThisIndex(0), CanBeGlobal(false), NeedsCopyDispose(false),
32 HasCXXObject(false), UsesStret(false), HasCapturedVariableLayout(false),
33 StructureType(0), Block(block),
36 // Skip asm prefix, if any. 'name' is usually taken directly from
37 // the mangled name of the enclosing function.
38 if (!name.empty() && name[0] == '\01')
39 name = name.substr(1);
42 // Anchor the vtable to this translation unit.
43 CodeGenModule::ByrefHelpers::~ByrefHelpers() {}
45 /// Build the given block as a global block.
46 static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
47 const CGBlockInfo &blockInfo,
48 llvm::Constant *blockFn);
50 /// Build the helper function to copy a block.
51 static llvm::Constant *buildCopyHelper(CodeGenModule &CGM,
52 const CGBlockInfo &blockInfo) {
53 return CodeGenFunction(CGM).GenerateCopyHelperFunction(blockInfo);
56 /// Build the helper function to dipose of a block.
57 static llvm::Constant *buildDisposeHelper(CodeGenModule &CGM,
58 const CGBlockInfo &blockInfo) {
59 return CodeGenFunction(CGM).GenerateDestroyHelperFunction(blockInfo);
62 /// buildBlockDescriptor - Build the block descriptor meta-data for a block.
63 /// buildBlockDescriptor is accessed from 5th field of the Block_literal
64 /// meta-data and contains stationary information about the block literal.
65 /// Its definition will have 4 (or optinally 6) words.
67 /// struct Block_descriptor {
68 /// unsigned long reserved;
69 /// unsigned long size; // size of Block_literal metadata in bytes.
70 /// void *copy_func_helper_decl; // optional copy helper.
71 /// void *destroy_func_decl; // optioanl destructor helper.
72 /// void *block_method_encoding_address; // @encode for block literal signature.
73 /// void *block_layout_info; // encoding of captured block variables.
76 static llvm::Constant *buildBlockDescriptor(CodeGenModule &CGM,
77 const CGBlockInfo &blockInfo) {
78 ASTContext &C = CGM.getContext();
80 llvm::Type *ulong = CGM.getTypes().ConvertType(C.UnsignedLongTy);
81 llvm::Type *i8p = CGM.getTypes().ConvertType(C.VoidPtrTy);
83 SmallVector<llvm::Constant*, 6> elements;
86 elements.push_back(llvm::ConstantInt::get(ulong, 0));
89 // FIXME: What is the right way to say this doesn't fit? We should give
90 // a user diagnostic in that case. Better fix would be to change the
92 elements.push_back(llvm::ConstantInt::get(ulong,
93 blockInfo.BlockSize.getQuantity()));
95 // Optional copy/dispose helpers.
96 if (blockInfo.NeedsCopyDispose) {
97 // copy_func_helper_decl
98 elements.push_back(buildCopyHelper(CGM, blockInfo));
101 elements.push_back(buildDisposeHelper(CGM, blockInfo));
104 // Signature. Mandatory ObjC-style method descriptor @encode sequence.
105 std::string typeAtEncoding =
106 CGM.getContext().getObjCEncodingForBlock(blockInfo.getBlockExpr());
107 elements.push_back(llvm::ConstantExpr::getBitCast(
108 CGM.GetAddrOfConstantCString(typeAtEncoding), i8p));
111 if (C.getLangOpts().ObjC1) {
112 if (CGM.getLangOpts().getGC() != LangOptions::NonGC)
113 elements.push_back(CGM.getObjCRuntime().BuildGCBlockLayout(CGM, blockInfo));
115 elements.push_back(CGM.getObjCRuntime().BuildRCBlockLayout(CGM, blockInfo));
118 elements.push_back(llvm::Constant::getNullValue(i8p));
120 llvm::Constant *init = llvm::ConstantStruct::getAnon(elements);
122 llvm::GlobalVariable *global =
123 new llvm::GlobalVariable(CGM.getModule(), init->getType(), true,
124 llvm::GlobalValue::InternalLinkage,
125 init, "__block_descriptor_tmp");
127 return llvm::ConstantExpr::getBitCast(global, CGM.getBlockDescriptorType());
131 Purely notional variadic template describing the layout of a block.
133 template <class _ResultType, class... _ParamTypes, class... _CaptureTypes>
134 struct Block_literal {
135 /// Initialized to one of:
136 /// extern void *_NSConcreteStackBlock[];
137 /// extern void *_NSConcreteGlobalBlock[];
139 /// In theory, we could start one off malloc'ed by setting
140 /// BLOCK_NEEDS_FREE, giving it a refcount of 1, and using
142 /// extern void *_NSConcreteMallocBlock[];
143 struct objc_class *isa;
145 /// These are the flags (with corresponding bit number) that the
146 /// compiler is actually supposed to know about.
147 /// 25. BLOCK_HAS_COPY_DISPOSE - indicates that the block
148 /// descriptor provides copy and dispose helper functions
149 /// 26. BLOCK_HAS_CXX_OBJ - indicates that there's a captured
150 /// object with a nontrivial destructor or copy constructor
151 /// 28. BLOCK_IS_GLOBAL - indicates that the block is allocated
153 /// 29. BLOCK_USE_STRET - indicates that the block function
154 /// uses stret, which objc_msgSend needs to know about
155 /// 30. BLOCK_HAS_SIGNATURE - indicates that the block has an
156 /// @encoded signature string
157 /// And we're not supposed to manipulate these:
158 /// 24. BLOCK_NEEDS_FREE - indicates that the block has been moved
159 /// to malloc'ed memory
160 /// 27. BLOCK_IS_GC - indicates that the block has been moved to
161 /// to GC-allocated memory
162 /// Additionally, the bottom 16 bits are a reference count which
163 /// should be zero on the stack.
166 /// Reserved; should be zero-initialized.
169 /// Function pointer generated from block literal.
170 _ResultType (*invoke)(Block_literal *, _ParamTypes...);
172 /// Block description metadata generated from block literal.
173 struct Block_descriptor *block_descriptor;
175 /// Captured values follow.
176 _CapturesTypes captures...;
180 /// The number of fields in a block header.
181 const unsigned BlockHeaderSize = 5;
184 /// A chunk of data that we actually have to capture in the block.
185 struct BlockLayoutChunk {
188 Qualifiers::ObjCLifetime Lifetime;
189 const BlockDecl::Capture *Capture; // null for 'this'
192 BlockLayoutChunk(CharUnits align, CharUnits size,
193 Qualifiers::ObjCLifetime lifetime,
194 const BlockDecl::Capture *capture,
196 : Alignment(align), Size(size), Lifetime(lifetime),
197 Capture(capture), Type(type) {}
199 /// Tell the block info that this chunk has the given field index.
200 void setIndex(CGBlockInfo &info, unsigned index) {
202 info.CXXThisIndex = index;
204 info.Captures[Capture->getVariable()]
205 = CGBlockInfo::Capture::makeIndex(index);
209 /// Order by 1) all __strong together 2) next, all byfref together 3) next,
210 /// all __weak together. Preserve descending alignment in all situations.
211 bool operator<(const BlockLayoutChunk &left, const BlockLayoutChunk &right) {
212 CharUnits LeftValue, RightValue;
213 bool LeftByref = left.Capture ? left.Capture->isByRef() : false;
214 bool RightByref = right.Capture ? right.Capture->isByRef() : false;
216 if (left.Lifetime == Qualifiers::OCL_Strong &&
217 left.Alignment >= right.Alignment)
218 LeftValue = CharUnits::fromQuantity(64);
219 else if (LeftByref && left.Alignment >= right.Alignment)
220 LeftValue = CharUnits::fromQuantity(32);
221 else if (left.Lifetime == Qualifiers::OCL_Weak &&
222 left.Alignment >= right.Alignment)
223 LeftValue = CharUnits::fromQuantity(16);
225 LeftValue = left.Alignment;
226 if (right.Lifetime == Qualifiers::OCL_Strong &&
227 right.Alignment >= left.Alignment)
228 RightValue = CharUnits::fromQuantity(64);
229 else if (RightByref && right.Alignment >= left.Alignment)
230 RightValue = CharUnits::fromQuantity(32);
231 else if (right.Lifetime == Qualifiers::OCL_Weak &&
232 right.Alignment >= left.Alignment)
233 RightValue = CharUnits::fromQuantity(16);
235 RightValue = right.Alignment;
237 return LeftValue > RightValue;
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 CXXRecordDecl *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 QualType type = var->getType();
271 // We can only do this if the variable is const.
272 if (!type.isConstQualified()) return 0;
274 // Furthermore, in C++ we have to worry about mutable fields:
275 // C++ [dcl.type.cv]p4:
276 // Except that any class member declared mutable can be
277 // modified, any attempt to modify a const object during its
278 // lifetime results in undefined behavior.
279 if (CGM.getLangOpts().CPlusPlus && !isSafeForCXXConstantCapture(type))
282 // If the variable doesn't have any initializer (shouldn't this be
283 // invalid?), it's not clear what we should do. Maybe capture as
285 const Expr *init = var->getInit();
288 return CGM.EmitConstantInit(*var, CGF);
291 /// Get the low bit of a nonzero character count. This is the
292 /// alignment of the nth byte if the 0th byte is universally aligned.
293 static CharUnits getLowBit(CharUnits v) {
294 return CharUnits::fromQuantity(v.getQuantity() & (~v.getQuantity() + 1));
297 static void initializeForBlockHeader(CodeGenModule &CGM, CGBlockInfo &info,
298 SmallVectorImpl<llvm::Type*> &elementTypes) {
299 ASTContext &C = CGM.getContext();
301 // The header is basically a 'struct { void *; int; int; void *; void *; }'.
302 CharUnits ptrSize, ptrAlign, intSize, intAlign;
303 llvm::tie(ptrSize, ptrAlign) = C.getTypeInfoInChars(C.VoidPtrTy);
304 llvm::tie(intSize, intAlign) = C.getTypeInfoInChars(C.IntTy);
306 // Are there crazy embedded platforms where this isn't true?
307 assert(intSize <= ptrSize && "layout assumptions horribly violated");
309 CharUnits headerSize = ptrSize;
310 if (2 * intSize < ptrAlign) headerSize += ptrSize;
311 else headerSize += 2 * intSize;
312 headerSize += 2 * ptrSize;
314 info.BlockAlign = ptrAlign;
315 info.BlockSize = headerSize;
317 assert(elementTypes.empty());
318 llvm::Type *i8p = CGM.getTypes().ConvertType(C.VoidPtrTy);
319 llvm::Type *intTy = CGM.getTypes().ConvertType(C.IntTy);
320 elementTypes.push_back(i8p);
321 elementTypes.push_back(intTy);
322 elementTypes.push_back(intTy);
323 elementTypes.push_back(i8p);
324 elementTypes.push_back(CGM.getBlockDescriptorType());
326 assert(elementTypes.size() == BlockHeaderSize);
329 /// Compute the layout of the given block. Attempts to lay the block
330 /// out with minimal space requirements.
331 static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF,
333 ASTContext &C = CGM.getContext();
334 const BlockDecl *block = info.getBlockDecl();
336 SmallVector<llvm::Type*, 8> elementTypes;
337 initializeForBlockHeader(CGM, info, elementTypes);
339 if (!block->hasCaptures()) {
341 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true);
342 info.CanBeGlobal = true;
345 else if (C.getLangOpts().ObjC1 &&
346 CGM.getLangOpts().getGC() == LangOptions::NonGC)
347 info.HasCapturedVariableLayout = true;
349 // Collect the layout chunks.
350 SmallVector<BlockLayoutChunk, 16> layout;
351 layout.reserve(block->capturesCXXThis() +
352 (block->capture_end() - block->capture_begin()));
354 CharUnits maxFieldAlign;
357 if (block->capturesCXXThis()) {
358 assert(CGF && CGF->CurFuncDecl && isa<CXXMethodDecl>(CGF->CurFuncDecl) &&
359 "Can't capture 'this' outside a method");
360 QualType thisType = cast<CXXMethodDecl>(CGF->CurFuncDecl)->getThisType(C);
362 llvm::Type *llvmType = CGM.getTypes().ConvertType(thisType);
363 std::pair<CharUnits,CharUnits> tinfo
364 = CGM.getContext().getTypeInfoInChars(thisType);
365 maxFieldAlign = std::max(maxFieldAlign, tinfo.second);
367 layout.push_back(BlockLayoutChunk(tinfo.second, tinfo.first,
368 Qualifiers::OCL_None,
372 // Next, all the block captures.
373 for (BlockDecl::capture_const_iterator ci = block->capture_begin(),
374 ce = block->capture_end(); ci != ce; ++ci) {
375 const VarDecl *variable = ci->getVariable();
378 // We have to copy/dispose of the __block reference.
379 info.NeedsCopyDispose = true;
381 // Just use void* instead of a pointer to the byref type.
382 QualType byRefPtrTy = C.VoidPtrTy;
384 llvm::Type *llvmType = CGM.getTypes().ConvertType(byRefPtrTy);
385 std::pair<CharUnits,CharUnits> tinfo
386 = CGM.getContext().getTypeInfoInChars(byRefPtrTy);
387 maxFieldAlign = std::max(maxFieldAlign, tinfo.second);
389 layout.push_back(BlockLayoutChunk(tinfo.second, tinfo.first,
390 Qualifiers::OCL_None,
395 // Otherwise, build a layout chunk with the size and alignment of
397 if (llvm::Constant *constant = tryCaptureAsConstant(CGM, CGF, variable)) {
398 info.Captures[variable] = CGBlockInfo::Capture::makeConstant(constant);
402 // If we have a lifetime qualifier, honor it for capture purposes.
403 // That includes *not* copying it if it's __unsafe_unretained.
404 Qualifiers::ObjCLifetime lifetime =
405 variable->getType().getObjCLifetime();
408 case Qualifiers::OCL_None: llvm_unreachable("impossible");
409 case Qualifiers::OCL_ExplicitNone:
410 case Qualifiers::OCL_Autoreleasing:
413 case Qualifiers::OCL_Strong:
414 case Qualifiers::OCL_Weak:
415 info.NeedsCopyDispose = true;
418 // Block pointers require copy/dispose. So do Objective-C pointers.
419 } else if (variable->getType()->isObjCRetainableType()) {
420 info.NeedsCopyDispose = true;
421 // used for mrr below.
422 lifetime = Qualifiers::OCL_Strong;
424 // So do types that require non-trivial copy construction.
425 } else if (ci->hasCopyExpr()) {
426 info.NeedsCopyDispose = true;
427 info.HasCXXObject = true;
429 // And so do types with destructors.
430 } else if (CGM.getLangOpts().CPlusPlus) {
431 if (const CXXRecordDecl *record =
432 variable->getType()->getAsCXXRecordDecl()) {
433 if (!record->hasTrivialDestructor()) {
434 info.HasCXXObject = true;
435 info.NeedsCopyDispose = true;
440 QualType VT = variable->getType();
441 CharUnits size = C.getTypeSizeInChars(VT);
442 CharUnits align = C.getDeclAlign(variable);
444 maxFieldAlign = std::max(maxFieldAlign, align);
446 llvm::Type *llvmType =
447 CGM.getTypes().ConvertTypeForMem(VT);
449 layout.push_back(BlockLayoutChunk(align, size, lifetime, &*ci, llvmType));
452 // If that was everything, we're done here.
453 if (layout.empty()) {
455 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true);
456 info.CanBeGlobal = true;
460 // Sort the layout by alignment. We have to use a stable sort here
461 // to get reproducible results. There should probably be an
462 // llvm::array_pod_stable_sort.
463 std::stable_sort(layout.begin(), layout.end());
465 // Needed for blocks layout info.
466 info.BlockHeaderForcedGapOffset = info.BlockSize;
467 info.BlockHeaderForcedGapSize = CharUnits::Zero();
469 CharUnits &blockSize = info.BlockSize;
470 info.BlockAlign = std::max(maxFieldAlign, info.BlockAlign);
472 // Assuming that the first byte in the header is maximally aligned,
473 // get the alignment of the first byte following the header.
474 CharUnits endAlign = getLowBit(blockSize);
476 // If the end of the header isn't satisfactorily aligned for the
477 // maximum thing, look for things that are okay with the header-end
478 // alignment, and keep appending them until we get something that's
479 // aligned right. This algorithm is only guaranteed optimal if
480 // that condition is satisfied at some point; otherwise we can get
482 // header // next byte has alignment 4
483 // something_with_size_5; // next byte has alignment 1
484 // something_with_alignment_8;
485 // which has 7 bytes of padding, as opposed to the naive solution
486 // which might have less (?).
487 if (endAlign < maxFieldAlign) {
488 SmallVectorImpl<BlockLayoutChunk>::iterator
489 li = layout.begin() + 1, le = layout.end();
491 // Look for something that the header end is already
492 // satisfactorily aligned for.
493 for (; li != le && endAlign < li->Alignment; ++li)
496 // If we found something that's naturally aligned for the end of
497 // the header, keep adding things...
499 SmallVectorImpl<BlockLayoutChunk>::iterator first = li;
500 for (; li != le; ++li) {
501 assert(endAlign >= li->Alignment);
503 li->setIndex(info, elementTypes.size());
504 elementTypes.push_back(li->Type);
505 blockSize += li->Size;
506 endAlign = getLowBit(blockSize);
508 // ...until we get to the alignment of the maximum field.
509 if (endAlign >= maxFieldAlign) {
511 // No user field was appended. So, a gap was added.
512 // Save total gap size for use in block layout bit map.
513 info.BlockHeaderForcedGapSize = li->Size;
518 // Don't re-append everything we just appended.
519 layout.erase(first, li);
523 assert(endAlign == getLowBit(blockSize));
525 // At this point, we just have to add padding if the end align still
526 // isn't aligned right.
527 if (endAlign < maxFieldAlign) {
528 CharUnits newBlockSize = blockSize.RoundUpToAlignment(maxFieldAlign);
529 CharUnits padding = newBlockSize - blockSize;
531 elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty,
532 padding.getQuantity()));
533 blockSize = newBlockSize;
534 endAlign = getLowBit(blockSize); // might be > maxFieldAlign
537 assert(endAlign >= maxFieldAlign);
538 assert(endAlign == getLowBit(blockSize));
539 // Slam everything else on now. This works because they have
540 // strictly decreasing alignment and we expect that size is always a
541 // multiple of alignment.
542 for (SmallVectorImpl<BlockLayoutChunk>::iterator
543 li = layout.begin(), le = layout.end(); li != le; ++li) {
544 assert(endAlign >= li->Alignment);
545 li->setIndex(info, elementTypes.size());
546 elementTypes.push_back(li->Type);
547 blockSize += li->Size;
548 endAlign = getLowBit(blockSize);
552 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true);
555 /// Enter the scope of a block. This should be run at the entrance to
556 /// a full-expression so that the block's cleanups are pushed at the
557 /// right place in the stack.
558 static void enterBlockScope(CodeGenFunction &CGF, BlockDecl *block) {
559 assert(CGF.HaveInsertPoint());
561 // Allocate the block info and place it at the head of the list.
562 CGBlockInfo &blockInfo =
563 *new CGBlockInfo(block, CGF.CurFn->getName());
564 blockInfo.NextBlockInfo = CGF.FirstBlockInfo;
565 CGF.FirstBlockInfo = &blockInfo;
567 // Compute information about the layout, etc., of this block,
568 // pushing cleanups as necessary.
569 computeBlockInfo(CGF.CGM, &CGF, blockInfo);
571 // Nothing else to do if it can be global.
572 if (blockInfo.CanBeGlobal) return;
574 // Make the allocation for the block.
576 CGF.CreateTempAlloca(blockInfo.StructureType, "block");
577 blockInfo.Address->setAlignment(blockInfo.BlockAlign.getQuantity());
579 // If there are cleanups to emit, enter them (but inactive).
580 if (!blockInfo.NeedsCopyDispose) return;
582 // Walk through the captures (in order) and find the ones not
583 // captured by constant.
584 for (BlockDecl::capture_const_iterator ci = block->capture_begin(),
585 ce = block->capture_end(); ci != ce; ++ci) {
586 // Ignore __block captures; there's nothing special in the
587 // on-stack block that we need to do for them.
588 if (ci->isByRef()) continue;
590 // Ignore variables that are constant-captured.
591 const VarDecl *variable = ci->getVariable();
592 CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
593 if (capture.isConstant()) continue;
595 // Ignore objects that aren't destructed.
596 QualType::DestructionKind dtorKind =
597 variable->getType().isDestructedType();
598 if (dtorKind == QualType::DK_none) continue;
600 CodeGenFunction::Destroyer *destroyer;
602 // Block captures count as local values and have imprecise semantics.
603 // They also can't be arrays, so need to worry about that.
604 if (dtorKind == QualType::DK_objc_strong_lifetime) {
605 destroyer = CodeGenFunction::destroyARCStrongImprecise;
607 destroyer = CGF.getDestroyer(dtorKind);
610 // GEP down to the address.
611 llvm::Value *addr = CGF.Builder.CreateStructGEP(blockInfo.Address,
614 // We can use that GEP as the dominating IP.
615 if (!blockInfo.DominatingIP)
616 blockInfo.DominatingIP = cast<llvm::Instruction>(addr);
618 CleanupKind cleanupKind = InactiveNormalCleanup;
619 bool useArrayEHCleanup = CGF.needsEHCleanup(dtorKind);
620 if (useArrayEHCleanup)
621 cleanupKind = InactiveNormalAndEHCleanup;
623 CGF.pushDestroy(cleanupKind, addr, variable->getType(),
624 destroyer, useArrayEHCleanup);
626 // Remember where that cleanup was.
627 capture.setCleanup(CGF.EHStack.stable_begin());
631 /// Enter a full-expression with a non-trivial number of objects to
632 /// clean up. This is in this file because, at the moment, the only
633 /// kind of cleanup object is a BlockDecl*.
634 void CodeGenFunction::enterNonTrivialFullExpression(const ExprWithCleanups *E) {
635 assert(E->getNumObjects() != 0);
636 ArrayRef<ExprWithCleanups::CleanupObject> cleanups = E->getObjects();
637 for (ArrayRef<ExprWithCleanups::CleanupObject>::iterator
638 i = cleanups.begin(), e = cleanups.end(); i != e; ++i) {
639 enterBlockScope(*this, *i);
643 /// Find the layout for the given block in a linked list and remove it.
644 static CGBlockInfo *findAndRemoveBlockInfo(CGBlockInfo **head,
645 const BlockDecl *block) {
647 assert(head && *head);
648 CGBlockInfo *cur = *head;
650 // If this is the block we're looking for, splice it out of the list.
651 if (cur->getBlockDecl() == block) {
652 *head = cur->NextBlockInfo;
656 head = &cur->NextBlockInfo;
660 /// Destroy a chain of block layouts.
661 void CodeGenFunction::destroyBlockInfos(CGBlockInfo *head) {
662 assert(head && "destroying an empty chain");
664 CGBlockInfo *cur = head;
665 head = cur->NextBlockInfo;
670 /// Emit a block literal expression in the current function.
671 llvm::Value *CodeGenFunction::EmitBlockLiteral(const BlockExpr *blockExpr) {
672 // If the block has no captures, we won't have a pre-computed
674 if (!blockExpr->getBlockDecl()->hasCaptures()) {
675 CGBlockInfo blockInfo(blockExpr->getBlockDecl(), CurFn->getName());
676 computeBlockInfo(CGM, this, blockInfo);
677 blockInfo.BlockExpression = blockExpr;
678 return EmitBlockLiteral(blockInfo);
681 // Find the block info for this block and take ownership of it.
682 OwningPtr<CGBlockInfo> blockInfo;
683 blockInfo.reset(findAndRemoveBlockInfo(&FirstBlockInfo,
684 blockExpr->getBlockDecl()));
686 blockInfo->BlockExpression = blockExpr;
687 return EmitBlockLiteral(*blockInfo);
690 llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo) {
691 // Using the computed layout, generate the actual block function.
692 bool isLambdaConv = blockInfo.getBlockDecl()->isConversionFromLambda();
693 llvm::Constant *blockFn
694 = CodeGenFunction(CGM, true).GenerateBlockFunction(CurGD, blockInfo,
697 blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy);
699 // If there is nothing to capture, we can emit this as a global block.
700 if (blockInfo.CanBeGlobal)
701 return buildGlobalBlock(CGM, blockInfo, blockFn);
703 // Otherwise, we have to emit this as a local block.
705 llvm::Constant *isa = CGM.getNSConcreteStackBlock();
706 isa = llvm::ConstantExpr::getBitCast(isa, VoidPtrTy);
708 // Build the block descriptor.
709 llvm::Constant *descriptor = buildBlockDescriptor(CGM, blockInfo);
711 llvm::AllocaInst *blockAddr = blockInfo.Address;
712 assert(blockAddr && "block has no address!");
714 // Compute the initial on-stack block flags.
715 BlockFlags flags = BLOCK_HAS_SIGNATURE;
716 if (blockInfo.HasCapturedVariableLayout) flags |= BLOCK_HAS_EXTENDED_LAYOUT;
717 if (blockInfo.NeedsCopyDispose) flags |= BLOCK_HAS_COPY_DISPOSE;
718 if (blockInfo.HasCXXObject) flags |= BLOCK_HAS_CXX_OBJ;
719 if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET;
721 // Initialize the block literal.
722 Builder.CreateStore(isa, Builder.CreateStructGEP(blockAddr, 0, "block.isa"));
723 Builder.CreateStore(llvm::ConstantInt::get(IntTy, flags.getBitMask()),
724 Builder.CreateStructGEP(blockAddr, 1, "block.flags"));
725 Builder.CreateStore(llvm::ConstantInt::get(IntTy, 0),
726 Builder.CreateStructGEP(blockAddr, 2, "block.reserved"));
727 Builder.CreateStore(blockFn, Builder.CreateStructGEP(blockAddr, 3,
729 Builder.CreateStore(descriptor, Builder.CreateStructGEP(blockAddr, 4,
730 "block.descriptor"));
732 // Finally, capture all the values into the block.
733 const BlockDecl *blockDecl = blockInfo.getBlockDecl();
736 if (blockDecl->capturesCXXThis()) {
737 llvm::Value *addr = Builder.CreateStructGEP(blockAddr,
738 blockInfo.CXXThisIndex,
739 "block.captured-this.addr");
740 Builder.CreateStore(LoadCXXThis(), addr);
743 // Next, captured variables.
744 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(),
745 ce = blockDecl->capture_end(); ci != ce; ++ci) {
746 const VarDecl *variable = ci->getVariable();
747 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
749 // Ignore constant captures.
750 if (capture.isConstant()) continue;
752 QualType type = variable->getType();
753 CharUnits align = getContext().getDeclAlign(variable);
755 // This will be a [[type]]*, except that a byref entry will just be
757 llvm::Value *blockField =
758 Builder.CreateStructGEP(blockAddr, capture.getIndex(),
761 // Compute the address of the thing we're going to move into the
764 if (BlockInfo && ci->isNested()) {
765 // We need to use the capture from the enclosing block.
766 const CGBlockInfo::Capture &enclosingCapture =
767 BlockInfo->getCapture(variable);
769 // This is a [[type]]*, except that a byref entry wil just be an i8**.
770 src = Builder.CreateStructGEP(LoadBlockStruct(),
771 enclosingCapture.getIndex(),
772 "block.capture.addr");
773 } else if (blockDecl->isConversionFromLambda()) {
774 // The lambda capture in a lambda's conversion-to-block-pointer is
775 // special; we'll simply emit it directly.
778 // Just look it up in the locals map, which will give us back a
779 // [[type]]*. If that doesn't work, do the more elaborate DRE
781 src = LocalDeclMap.lookup(variable);
783 DeclRefExpr declRef(const_cast<VarDecl*>(variable),
784 /*refersToEnclosing*/ ci->isNested(), type,
785 VK_LValue, SourceLocation());
786 src = EmitDeclRefLValue(&declRef).getAddress();
790 // For byrefs, we just write the pointer to the byref struct into
791 // the block field. There's no need to chase the forwarding
792 // pointer at this point, since we're building something that will
793 // live a shorter life than the stack byref anyway.
795 // Get a void* that points to the byref struct.
797 src = Builder.CreateAlignedLoad(src, align.getQuantity(),
800 src = Builder.CreateBitCast(src, VoidPtrTy);
802 // Write that void* into the capture field.
803 Builder.CreateAlignedStore(src, blockField, align.getQuantity());
805 // If we have a copy constructor, evaluate that into the block field.
806 } else if (const Expr *copyExpr = ci->getCopyExpr()) {
807 if (blockDecl->isConversionFromLambda()) {
808 // If we have a lambda conversion, emit the expression
809 // directly into the block instead.
811 AggValueSlot::forAddr(blockField, align, Qualifiers(),
812 AggValueSlot::IsDestructed,
813 AggValueSlot::DoesNotNeedGCBarriers,
814 AggValueSlot::IsNotAliased);
815 EmitAggExpr(copyExpr, Slot);
817 EmitSynthesizedCXXCopyCtor(blockField, src, copyExpr);
820 // If it's a reference variable, copy the reference into the block field.
821 } else if (type->isReferenceType()) {
823 Builder.CreateAlignedLoad(src, align.getQuantity(), "ref.val");
824 Builder.CreateAlignedStore(ref, blockField, align.getQuantity());
826 // If this is an ARC __strong block-pointer variable, don't do a
829 // TODO: this can be generalized into the normal initialization logic:
830 // we should never need to do a block-copy when initializing a local
831 // variable, because the local variable's lifetime should be strictly
832 // contained within the stack block's.
833 } else if (type.getObjCLifetime() == Qualifiers::OCL_Strong &&
834 type->isBlockPointerType()) {
835 // Load the block and do a simple retain.
836 LValue srcLV = MakeAddrLValue(src, type, align);
837 llvm::Value *value = EmitLoadOfScalar(srcLV, SourceLocation());
838 value = EmitARCRetainNonBlock(value);
840 // Do a primitive store to the block field.
841 LValue destLV = MakeAddrLValue(blockField, type, align);
842 EmitStoreOfScalar(value, destLV, /*init*/ true);
844 // Otherwise, fake up a POD copy into the block field.
846 // Fake up a new variable so that EmitScalarInit doesn't think
847 // we're referring to the variable in its own initializer.
848 ImplicitParamDecl blockFieldPseudoVar(/*DC*/ 0, SourceLocation(),
851 // We use one of these or the other depending on whether the
852 // reference is nested.
853 DeclRefExpr declRef(const_cast<VarDecl*>(variable),
854 /*refersToEnclosing*/ ci->isNested(), type,
855 VK_LValue, SourceLocation());
857 ImplicitCastExpr l2r(ImplicitCastExpr::OnStack, type, CK_LValueToRValue,
858 &declRef, VK_RValue);
859 EmitExprAsInit(&l2r, &blockFieldPseudoVar,
860 MakeAddrLValue(blockField, type, align),
861 /*captured by init*/ false);
864 // Activate the cleanup if layout pushed one.
865 if (!ci->isByRef()) {
866 EHScopeStack::stable_iterator cleanup = capture.getCleanup();
867 if (cleanup.isValid())
868 ActivateCleanupBlock(cleanup, blockInfo.DominatingIP);
872 // Cast to the converted block-pointer type, which happens (somewhat
873 // unfortunately) to be a pointer to function type.
874 llvm::Value *result =
875 Builder.CreateBitCast(blockAddr,
876 ConvertType(blockInfo.getBlockExpr()->getType()));
882 llvm::Type *CodeGenModule::getBlockDescriptorType() {
883 if (BlockDescriptorType)
884 return BlockDescriptorType;
886 llvm::Type *UnsignedLongTy =
887 getTypes().ConvertType(getContext().UnsignedLongTy);
889 // struct __block_descriptor {
890 // unsigned long reserved;
891 // unsigned long block_size;
893 // // later, the following will be added
896 // void (*copyHelper)();
897 // void (*copyHelper)();
898 // } helpers; // !!! optional
900 // const char *signature; // the block signature
901 // const char *layout; // reserved
903 BlockDescriptorType =
904 llvm::StructType::create("struct.__block_descriptor",
905 UnsignedLongTy, UnsignedLongTy, NULL);
907 // Now form a pointer to that.
908 BlockDescriptorType = llvm::PointerType::getUnqual(BlockDescriptorType);
909 return BlockDescriptorType;
912 llvm::Type *CodeGenModule::getGenericBlockLiteralType() {
913 if (GenericBlockLiteralType)
914 return GenericBlockLiteralType;
916 llvm::Type *BlockDescPtrTy = getBlockDescriptorType();
918 // struct __block_literal_generic {
922 // void (*__invoke)(void *);
923 // struct __block_descriptor *__descriptor;
925 GenericBlockLiteralType =
926 llvm::StructType::create("struct.__block_literal_generic",
927 VoidPtrTy, IntTy, IntTy, VoidPtrTy,
928 BlockDescPtrTy, NULL);
930 return GenericBlockLiteralType;
934 RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr *E,
935 ReturnValueSlot ReturnValue) {
936 const BlockPointerType *BPT =
937 E->getCallee()->getType()->getAs<BlockPointerType>();
939 llvm::Value *Callee = EmitScalarExpr(E->getCallee());
941 // Get a pointer to the generic block literal.
942 llvm::Type *BlockLiteralTy =
943 llvm::PointerType::getUnqual(CGM.getGenericBlockLiteralType());
945 // Bitcast the callee to a block literal.
946 llvm::Value *BlockLiteral =
947 Builder.CreateBitCast(Callee, BlockLiteralTy, "block.literal");
949 // Get the function pointer from the literal.
950 llvm::Value *FuncPtr = Builder.CreateStructGEP(BlockLiteral, 3);
952 BlockLiteral = Builder.CreateBitCast(BlockLiteral, VoidPtrTy);
954 // Add the block literal.
956 Args.add(RValue::get(BlockLiteral), getContext().VoidPtrTy);
958 QualType FnType = BPT->getPointeeType();
960 // And the rest of the arguments.
961 EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(),
962 E->arg_begin(), E->arg_end());
964 // Load the function.
965 llvm::Value *Func = Builder.CreateLoad(FuncPtr);
967 const FunctionType *FuncTy = FnType->castAs<FunctionType>();
968 const CGFunctionInfo &FnInfo =
969 CGM.getTypes().arrangeBlockFunctionCall(Args, FuncTy);
971 // Cast the function pointer to the right type.
972 llvm::Type *BlockFTy = CGM.getTypes().GetFunctionType(FnInfo);
974 llvm::Type *BlockFTyPtr = llvm::PointerType::getUnqual(BlockFTy);
975 Func = Builder.CreateBitCast(Func, BlockFTyPtr);
977 // And call the block.
978 return EmitCall(FnInfo, Func, ReturnValue, Args);
981 llvm::Value *CodeGenFunction::GetAddrOfBlockDecl(const VarDecl *variable,
983 assert(BlockInfo && "evaluating block ref without block information?");
984 const CGBlockInfo::Capture &capture = BlockInfo->getCapture(variable);
986 // Handle constant captures.
987 if (capture.isConstant()) return LocalDeclMap[variable];
990 Builder.CreateStructGEP(LoadBlockStruct(), capture.getIndex(),
991 "block.capture.addr");
994 // addr should be a void** right now. Load, then cast the result
997 addr = Builder.CreateLoad(addr);
998 llvm::PointerType *byrefPointerType
999 = llvm::PointerType::get(BuildByRefType(variable), 0);
1000 addr = Builder.CreateBitCast(addr, byrefPointerType,
1003 // Follow the forwarding pointer.
1004 addr = Builder.CreateStructGEP(addr, 1, "byref.forwarding");
1005 addr = Builder.CreateLoad(addr, "byref.addr.forwarded");
1007 // Cast back to byref* and GEP over to the actual object.
1008 addr = Builder.CreateBitCast(addr, byrefPointerType);
1009 addr = Builder.CreateStructGEP(addr, getByRefValueLLVMField(variable),
1010 variable->getNameAsString());
1013 if (variable->getType()->isReferenceType())
1014 addr = Builder.CreateLoad(addr, "ref.tmp");
1020 CodeGenModule::GetAddrOfGlobalBlock(const BlockExpr *blockExpr,
1022 CGBlockInfo blockInfo(blockExpr->getBlockDecl(), name);
1023 blockInfo.BlockExpression = blockExpr;
1025 // Compute information about the layout, etc., of this block.
1026 computeBlockInfo(*this, 0, blockInfo);
1028 // Using that metadata, generate the actual block function.
1029 llvm::Constant *blockFn;
1031 llvm::DenseMap<const Decl*, llvm::Value*> LocalDeclMap;
1032 blockFn = CodeGenFunction(*this).GenerateBlockFunction(GlobalDecl(),
1037 blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy);
1039 return buildGlobalBlock(*this, blockInfo, blockFn);
1042 static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
1043 const CGBlockInfo &blockInfo,
1044 llvm::Constant *blockFn) {
1045 assert(blockInfo.CanBeGlobal);
1047 // Generate the constants for the block literal initializer.
1048 llvm::Constant *fields[BlockHeaderSize];
1051 fields[0] = CGM.getNSConcreteGlobalBlock();
1054 BlockFlags flags = BLOCK_IS_GLOBAL | BLOCK_HAS_SIGNATURE;
1055 if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET;
1057 fields[1] = llvm::ConstantInt::get(CGM.IntTy, flags.getBitMask());
1060 fields[2] = llvm::Constant::getNullValue(CGM.IntTy);
1063 fields[3] = blockFn;
1066 fields[4] = buildBlockDescriptor(CGM, blockInfo);
1068 llvm::Constant *init = llvm::ConstantStruct::getAnon(fields);
1070 llvm::GlobalVariable *literal =
1071 new llvm::GlobalVariable(CGM.getModule(),
1074 llvm::GlobalVariable::InternalLinkage,
1076 "__block_literal_global");
1077 literal->setAlignment(blockInfo.BlockAlign.getQuantity());
1079 // Return a constant of the appropriately-casted type.
1080 llvm::Type *requiredType =
1081 CGM.getTypes().ConvertType(blockInfo.getBlockExpr()->getType());
1082 return llvm::ConstantExpr::getBitCast(literal, requiredType);
1086 CodeGenFunction::GenerateBlockFunction(GlobalDecl GD,
1087 const CGBlockInfo &blockInfo,
1088 const DeclMapTy &ldm,
1089 bool IsLambdaConversionToBlock) {
1090 const BlockDecl *blockDecl = blockInfo.getBlockDecl();
1094 BlockInfo = &blockInfo;
1096 // Arrange for local static and local extern declarations to appear
1097 // to be local to this function as well, in case they're directly
1098 // referenced in a block.
1099 for (DeclMapTy::const_iterator i = ldm.begin(), e = ldm.end(); i != e; ++i) {
1100 const VarDecl *var = dyn_cast<VarDecl>(i->first);
1101 if (var && !var->hasLocalStorage())
1102 LocalDeclMap[var] = i->second;
1105 // Begin building the function declaration.
1107 // Build the argument list.
1108 FunctionArgList args;
1110 // The first argument is the block pointer. Just take it as a void*
1111 // and cast it later.
1112 QualType selfTy = getContext().VoidPtrTy;
1113 IdentifierInfo *II = &CGM.getContext().Idents.get(".block_descriptor");
1115 ImplicitParamDecl selfDecl(const_cast<BlockDecl*>(blockDecl),
1116 SourceLocation(), II, selfTy);
1117 args.push_back(&selfDecl);
1119 // Now add the rest of the parameters.
1120 for (BlockDecl::param_const_iterator i = blockDecl->param_begin(),
1121 e = blockDecl->param_end(); i != e; ++i)
1124 // Create the function declaration.
1125 const FunctionProtoType *fnType = blockInfo.getBlockExpr()->getFunctionType();
1126 const CGFunctionInfo &fnInfo =
1127 CGM.getTypes().arrangeFunctionDeclaration(fnType->getResultType(), args,
1128 fnType->getExtInfo(),
1129 fnType->isVariadic());
1130 if (CGM.ReturnTypeUsesSRet(fnInfo))
1131 blockInfo.UsesStret = true;
1133 llvm::FunctionType *fnLLVMType = CGM.getTypes().GetFunctionType(fnInfo);
1136 CGM.getBlockMangledName(GD, name, blockDecl);
1137 llvm::Function *fn =
1138 llvm::Function::Create(fnLLVMType, llvm::GlobalValue::InternalLinkage,
1139 name.getString(), &CGM.getModule());
1140 CGM.SetInternalFunctionAttributes(blockDecl, fn, fnInfo);
1142 // Begin generating the function.
1143 StartFunction(blockDecl, fnType->getResultType(), fn, fnInfo, args,
1144 blockInfo.getBlockExpr()->getBody()->getLocStart());
1146 // Okay. Undo some of what StartFunction did.
1148 // Pull the 'self' reference out of the local decl map.
1149 llvm::Value *blockAddr = LocalDeclMap[&selfDecl];
1150 LocalDeclMap.erase(&selfDecl);
1151 BlockPointer = Builder.CreateBitCast(blockAddr,
1152 blockInfo.StructureType->getPointerTo(),
1154 // At -O0 we generate an explicit alloca for the BlockPointer, so the RA
1155 // won't delete the dbg.declare intrinsics for captured variables.
1156 llvm::Value *BlockPointerDbgLoc = BlockPointer;
1157 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1158 // Allocate a stack slot for it, so we can point the debugger to it
1159 llvm::AllocaInst *Alloca = CreateTempAlloca(BlockPointer->getType(),
1161 unsigned Align = getContext().getDeclAlign(&selfDecl).getQuantity();
1162 Alloca->setAlignment(Align);
1163 // Set the DebugLocation to empty, so the store is recognized as a
1164 // frame setup instruction by llvm::DwarfDebug::beginFunction().
1165 NoLocation NL(*this, Builder);
1166 Builder.CreateAlignedStore(BlockPointer, Alloca, Align);
1167 BlockPointerDbgLoc = Alloca;
1170 // If we have a C++ 'this' reference, go ahead and force it into
1172 if (blockDecl->capturesCXXThis()) {
1173 llvm::Value *addr = Builder.CreateStructGEP(BlockPointer,
1174 blockInfo.CXXThisIndex,
1175 "block.captured-this");
1176 CXXThisValue = Builder.CreateLoad(addr, "this");
1179 // Also force all the constant captures.
1180 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(),
1181 ce = blockDecl->capture_end(); ci != ce; ++ci) {
1182 const VarDecl *variable = ci->getVariable();
1183 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
1184 if (!capture.isConstant()) continue;
1186 unsigned align = getContext().getDeclAlign(variable).getQuantity();
1188 llvm::AllocaInst *alloca =
1189 CreateMemTemp(variable->getType(), "block.captured-const");
1190 alloca->setAlignment(align);
1192 Builder.CreateAlignedStore(capture.getConstant(), alloca, align);
1194 LocalDeclMap[variable] = alloca;
1197 // Save a spot to insert the debug information for all the DeclRefExprs.
1198 llvm::BasicBlock *entry = Builder.GetInsertBlock();
1199 llvm::BasicBlock::iterator entry_ptr = Builder.GetInsertPoint();
1202 if (IsLambdaConversionToBlock)
1203 EmitLambdaBlockInvokeBody();
1205 EmitStmt(blockDecl->getBody());
1207 // Remember where we were...
1208 llvm::BasicBlock *resume = Builder.GetInsertBlock();
1210 // Go back to the entry.
1212 Builder.SetInsertPoint(entry, entry_ptr);
1214 // Emit debug information for all the DeclRefExprs.
1215 // FIXME: also for 'this'
1216 if (CGDebugInfo *DI = getDebugInfo()) {
1217 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(),
1218 ce = blockDecl->capture_end(); ci != ce; ++ci) {
1219 const VarDecl *variable = ci->getVariable();
1220 DI->EmitLocation(Builder, variable->getLocation());
1222 if (CGM.getCodeGenOpts().getDebugInfo()
1223 >= CodeGenOptions::LimitedDebugInfo) {
1224 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
1225 if (capture.isConstant()) {
1226 DI->EmitDeclareOfAutoVariable(variable, LocalDeclMap[variable],
1231 DI->EmitDeclareOfBlockDeclRefVariable(variable, BlockPointerDbgLoc,
1232 Builder, blockInfo);
1235 // Recover location if it was changed in the above loop.
1236 DI->EmitLocation(Builder,
1237 cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc());
1240 // And resume where we left off.
1242 Builder.ClearInsertionPoint();
1244 Builder.SetInsertPoint(resume);
1246 FinishFunction(cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc());
1252 notes.push_back(HelperInfo());
1253 HelperInfo ¬e = notes.back();
1254 note.index = capture.getIndex();
1255 note.RequiresCopying = (ci->hasCopyExpr() || BlockRequiresCopying(type));
1256 note.cxxbar_import = ci->getCopyExpr();
1258 if (ci->isByRef()) {
1259 note.flag = BLOCK_FIELD_IS_BYREF;
1260 if (type.isObjCGCWeak())
1261 note.flag |= BLOCK_FIELD_IS_WEAK;
1262 } else if (type->isBlockPointerType()) {
1263 note.flag = BLOCK_FIELD_IS_BLOCK;
1265 note.flag = BLOCK_FIELD_IS_OBJECT;
1270 /// Generate the copy-helper function for a block closure object:
1271 /// static void block_copy_helper(block_t *dst, block_t *src);
1272 /// The runtime will have previously initialized 'dst' by doing a
1273 /// bit-copy of 'src'.
1275 /// Note that this copies an entire block closure object to the heap;
1276 /// it should not be confused with a 'byref copy helper', which moves
1277 /// the contents of an individual __block variable to the heap.
1279 CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) {
1280 ASTContext &C = getContext();
1282 FunctionArgList args;
1283 ImplicitParamDecl dstDecl(0, SourceLocation(), 0, C.VoidPtrTy);
1284 args.push_back(&dstDecl);
1285 ImplicitParamDecl srcDecl(0, SourceLocation(), 0, C.VoidPtrTy);
1286 args.push_back(&srcDecl);
1288 const CGFunctionInfo &FI =
1289 CGM.getTypes().arrangeFunctionDeclaration(C.VoidTy, args,
1290 FunctionType::ExtInfo(),
1291 /*variadic*/ false);
1293 // FIXME: it would be nice if these were mergeable with things with
1294 // identical semantics.
1295 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
1297 llvm::Function *Fn =
1298 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
1299 "__copy_helper_block_", &CGM.getModule());
1302 = &CGM.getContext().Idents.get("__copy_helper_block_");
1304 FunctionDecl *FD = FunctionDecl::Create(C,
1305 C.getTranslationUnitDecl(),
1307 SourceLocation(), II, C.VoidTy, 0,
1311 // Create a scope with an artificial location for the body of this function.
1312 ArtificialLocation AL(*this, Builder);
1313 StartFunction(FD, C.VoidTy, Fn, FI, args, SourceLocation());
1316 llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
1318 llvm::Value *src = GetAddrOfLocalVar(&srcDecl);
1319 src = Builder.CreateLoad(src);
1320 src = Builder.CreateBitCast(src, structPtrTy, "block.source");
1322 llvm::Value *dst = GetAddrOfLocalVar(&dstDecl);
1323 dst = Builder.CreateLoad(dst);
1324 dst = Builder.CreateBitCast(dst, structPtrTy, "block.dest");
1326 const BlockDecl *blockDecl = blockInfo.getBlockDecl();
1328 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(),
1329 ce = blockDecl->capture_end(); ci != ce; ++ci) {
1330 const VarDecl *variable = ci->getVariable();
1331 QualType type = variable->getType();
1333 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
1334 if (capture.isConstant()) continue;
1336 const Expr *copyExpr = ci->getCopyExpr();
1337 BlockFieldFlags flags;
1339 bool useARCWeakCopy = false;
1340 bool useARCStrongCopy = false;
1343 assert(!ci->isByRef());
1344 // don't bother computing flags
1346 } else if (ci->isByRef()) {
1347 flags = BLOCK_FIELD_IS_BYREF;
1348 if (type.isObjCGCWeak())
1349 flags |= BLOCK_FIELD_IS_WEAK;
1351 } else if (type->isObjCRetainableType()) {
1352 flags = BLOCK_FIELD_IS_OBJECT;
1353 bool isBlockPointer = type->isBlockPointerType();
1355 flags = BLOCK_FIELD_IS_BLOCK;
1357 // Special rules for ARC captures:
1358 if (getLangOpts().ObjCAutoRefCount) {
1359 Qualifiers qs = type.getQualifiers();
1361 // We need to register __weak direct captures with the runtime.
1362 if (qs.getObjCLifetime() == Qualifiers::OCL_Weak) {
1363 useARCWeakCopy = true;
1365 // We need to retain the copied value for __strong direct captures.
1366 } else if (qs.getObjCLifetime() == Qualifiers::OCL_Strong) {
1367 // If it's a block pointer, we have to copy the block and
1368 // assign that to the destination pointer, so we might as
1369 // well use _Block_object_assign. Otherwise we can avoid that.
1370 if (!isBlockPointer)
1371 useARCStrongCopy = true;
1373 // Otherwise the memcpy is fine.
1378 // Non-ARC captures of retainable pointers are strong and
1379 // therefore require a call to _Block_object_assign.
1387 unsigned index = capture.getIndex();
1388 llvm::Value *srcField = Builder.CreateStructGEP(src, index);
1389 llvm::Value *dstField = Builder.CreateStructGEP(dst, index);
1391 // If there's an explicit copy expression, we do that.
1393 EmitSynthesizedCXXCopyCtor(dstField, srcField, copyExpr);
1394 } else if (useARCWeakCopy) {
1395 EmitARCCopyWeak(dstField, srcField);
1397 llvm::Value *srcValue = Builder.CreateLoad(srcField, "blockcopy.src");
1398 if (useARCStrongCopy) {
1399 // At -O0, store null into the destination field (so that the
1400 // storeStrong doesn't over-release) and then call storeStrong.
1401 // This is a workaround to not having an initStrong call.
1402 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1403 llvm::PointerType *ty = cast<llvm::PointerType>(srcValue->getType());
1404 llvm::Value *null = llvm::ConstantPointerNull::get(ty);
1405 Builder.CreateStore(null, dstField);
1406 EmitARCStoreStrongCall(dstField, srcValue, true);
1408 // With optimization enabled, take advantage of the fact that
1409 // the blocks runtime guarantees a memcpy of the block data, and
1410 // just emit a retain of the src field.
1412 EmitARCRetainNonBlock(srcValue);
1414 // We don't need this anymore, so kill it. It's not quite
1415 // worth the annoyance to avoid creating it in the first place.
1416 cast<llvm::Instruction>(dstField)->eraseFromParent();
1419 srcValue = Builder.CreateBitCast(srcValue, VoidPtrTy);
1420 llvm::Value *dstAddr = Builder.CreateBitCast(dstField, VoidPtrTy);
1421 llvm::Value *args[] = {
1422 dstAddr, srcValue, llvm::ConstantInt::get(Int32Ty, flags.getBitMask())
1425 bool copyCanThrow = false;
1426 if (ci->isByRef() && variable->getType()->getAsCXXRecordDecl()) {
1427 const Expr *copyExpr =
1428 CGM.getContext().getBlockVarCopyInits(variable);
1430 copyCanThrow = true; // FIXME: reuse the noexcept logic
1435 EmitRuntimeCallOrInvoke(CGM.getBlockObjectAssign(), args);
1437 EmitNounwindRuntimeCall(CGM.getBlockObjectAssign(), args);
1445 return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
1448 /// Generate the destroy-helper function for a block closure object:
1449 /// static void block_destroy_helper(block_t *theBlock);
1451 /// Note that this destroys a heap-allocated block closure object;
1452 /// it should not be confused with a 'byref destroy helper', which
1453 /// destroys the heap-allocated contents of an individual __block
1456 CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) {
1457 ASTContext &C = getContext();
1459 FunctionArgList args;
1460 ImplicitParamDecl srcDecl(0, SourceLocation(), 0, C.VoidPtrTy);
1461 args.push_back(&srcDecl);
1463 const CGFunctionInfo &FI =
1464 CGM.getTypes().arrangeFunctionDeclaration(C.VoidTy, args,
1465 FunctionType::ExtInfo(),
1466 /*variadic*/ false);
1468 // FIXME: We'd like to put these into a mergable by content, with
1469 // internal linkage.
1470 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
1472 llvm::Function *Fn =
1473 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
1474 "__destroy_helper_block_", &CGM.getModule());
1477 = &CGM.getContext().Idents.get("__destroy_helper_block_");
1479 FunctionDecl *FD = FunctionDecl::Create(C, C.getTranslationUnitDecl(),
1481 SourceLocation(), II, C.VoidTy, 0,
1484 // Create a scope with an artificial location for the body of this function.
1485 ArtificialLocation AL(*this, Builder);
1486 StartFunction(FD, C.VoidTy, Fn, FI, args, SourceLocation());
1489 llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
1491 llvm::Value *src = GetAddrOfLocalVar(&srcDecl);
1492 src = Builder.CreateLoad(src);
1493 src = Builder.CreateBitCast(src, structPtrTy, "block");
1495 const BlockDecl *blockDecl = blockInfo.getBlockDecl();
1497 CodeGenFunction::RunCleanupsScope cleanups(*this);
1499 for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(),
1500 ce = blockDecl->capture_end(); ci != ce; ++ci) {
1501 const VarDecl *variable = ci->getVariable();
1502 QualType type = variable->getType();
1504 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
1505 if (capture.isConstant()) continue;
1507 BlockFieldFlags flags;
1508 const CXXDestructorDecl *dtor = 0;
1510 bool useARCWeakDestroy = false;
1511 bool useARCStrongDestroy = false;
1513 if (ci->isByRef()) {
1514 flags = BLOCK_FIELD_IS_BYREF;
1515 if (type.isObjCGCWeak())
1516 flags |= BLOCK_FIELD_IS_WEAK;
1517 } else if (const CXXRecordDecl *record = type->getAsCXXRecordDecl()) {
1518 if (record->hasTrivialDestructor())
1520 dtor = record->getDestructor();
1521 } else if (type->isObjCRetainableType()) {
1522 flags = BLOCK_FIELD_IS_OBJECT;
1523 if (type->isBlockPointerType())
1524 flags = BLOCK_FIELD_IS_BLOCK;
1526 // Special rules for ARC captures.
1527 if (getLangOpts().ObjCAutoRefCount) {
1528 Qualifiers qs = type.getQualifiers();
1530 // Don't generate special dispose logic for a captured object
1531 // unless it's __strong or __weak.
1532 if (!qs.hasStrongOrWeakObjCLifetime())
1535 // Support __weak direct captures.
1536 if (qs.getObjCLifetime() == Qualifiers::OCL_Weak)
1537 useARCWeakDestroy = true;
1539 // Tools really want us to use objc_storeStrong here.
1541 useARCStrongDestroy = true;
1547 unsigned index = capture.getIndex();
1548 llvm::Value *srcField = Builder.CreateStructGEP(src, index);
1550 // If there's an explicit copy expression, we do that.
1552 PushDestructorCleanup(dtor, srcField);
1554 // If this is a __weak capture, emit the release directly.
1555 } else if (useARCWeakDestroy) {
1556 EmitARCDestroyWeak(srcField);
1558 // Destroy strong objects with a call if requested.
1559 } else if (useARCStrongDestroy) {
1560 EmitARCDestroyStrong(srcField, ARCImpreciseLifetime);
1562 // Otherwise we call _Block_object_dispose. It wouldn't be too
1563 // hard to just emit this as a cleanup if we wanted to make sure
1564 // that things were done in reverse.
1566 llvm::Value *value = Builder.CreateLoad(srcField);
1567 value = Builder.CreateBitCast(value, VoidPtrTy);
1568 BuildBlockRelease(value, flags);
1572 cleanups.ForceCleanup();
1576 return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
1581 /// Emits the copy/dispose helper functions for a __block object of id type.
1582 class ObjectByrefHelpers : public CodeGenModule::ByrefHelpers {
1583 BlockFieldFlags Flags;
1586 ObjectByrefHelpers(CharUnits alignment, BlockFieldFlags flags)
1587 : ByrefHelpers(alignment), Flags(flags) {}
1589 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField,
1590 llvm::Value *srcField) {
1591 destField = CGF.Builder.CreateBitCast(destField, CGF.VoidPtrTy);
1593 srcField = CGF.Builder.CreateBitCast(srcField, CGF.VoidPtrPtrTy);
1594 llvm::Value *srcValue = CGF.Builder.CreateLoad(srcField);
1596 unsigned flags = (Flags | BLOCK_BYREF_CALLER).getBitMask();
1598 llvm::Value *flagsVal = llvm::ConstantInt::get(CGF.Int32Ty, flags);
1599 llvm::Value *fn = CGF.CGM.getBlockObjectAssign();
1601 llvm::Value *args[] = { destField, srcValue, flagsVal };
1602 CGF.EmitNounwindRuntimeCall(fn, args);
1605 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) {
1606 field = CGF.Builder.CreateBitCast(field, CGF.Int8PtrTy->getPointerTo(0));
1607 llvm::Value *value = CGF.Builder.CreateLoad(field);
1609 CGF.BuildBlockRelease(value, Flags | BLOCK_BYREF_CALLER);
1612 void profileImpl(llvm::FoldingSetNodeID &id) const {
1613 id.AddInteger(Flags.getBitMask());
1617 /// Emits the copy/dispose helpers for an ARC __block __weak variable.
1618 class ARCWeakByrefHelpers : public CodeGenModule::ByrefHelpers {
1620 ARCWeakByrefHelpers(CharUnits alignment) : ByrefHelpers(alignment) {}
1622 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField,
1623 llvm::Value *srcField) {
1624 CGF.EmitARCMoveWeak(destField, srcField);
1627 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) {
1628 CGF.EmitARCDestroyWeak(field);
1631 void profileImpl(llvm::FoldingSetNodeID &id) const {
1632 // 0 is distinguishable from all pointers and byref flags
1637 /// Emits the copy/dispose helpers for an ARC __block __strong variable
1638 /// that's not of block-pointer type.
1639 class ARCStrongByrefHelpers : public CodeGenModule::ByrefHelpers {
1641 ARCStrongByrefHelpers(CharUnits alignment) : ByrefHelpers(alignment) {}
1643 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField,
1644 llvm::Value *srcField) {
1645 // Do a "move" by copying the value and then zeroing out the old
1648 llvm::LoadInst *value = CGF.Builder.CreateLoad(srcField);
1649 value->setAlignment(Alignment.getQuantity());
1652 llvm::ConstantPointerNull::get(cast<llvm::PointerType>(value->getType()));
1654 if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0) {
1655 llvm::StoreInst *store = CGF.Builder.CreateStore(null, destField);
1656 store->setAlignment(Alignment.getQuantity());
1657 CGF.EmitARCStoreStrongCall(destField, value, /*ignored*/ true);
1658 CGF.EmitARCStoreStrongCall(srcField, null, /*ignored*/ true);
1661 llvm::StoreInst *store = CGF.Builder.CreateStore(value, destField);
1662 store->setAlignment(Alignment.getQuantity());
1664 store = CGF.Builder.CreateStore(null, srcField);
1665 store->setAlignment(Alignment.getQuantity());
1668 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) {
1669 CGF.EmitARCDestroyStrong(field, ARCImpreciseLifetime);
1672 void profileImpl(llvm::FoldingSetNodeID &id) const {
1673 // 1 is distinguishable from all pointers and byref flags
1678 /// Emits the copy/dispose helpers for an ARC __block __strong
1679 /// variable that's of block-pointer type.
1680 class ARCStrongBlockByrefHelpers : public CodeGenModule::ByrefHelpers {
1682 ARCStrongBlockByrefHelpers(CharUnits alignment) : ByrefHelpers(alignment) {}
1684 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField,
1685 llvm::Value *srcField) {
1686 // Do the copy with objc_retainBlock; that's all that
1687 // _Block_object_assign would do anyway, and we'd have to pass the
1688 // right arguments to make sure it doesn't get no-op'ed.
1689 llvm::LoadInst *oldValue = CGF.Builder.CreateLoad(srcField);
1690 oldValue->setAlignment(Alignment.getQuantity());
1692 llvm::Value *copy = CGF.EmitARCRetainBlock(oldValue, /*mandatory*/ true);
1694 llvm::StoreInst *store = CGF.Builder.CreateStore(copy, destField);
1695 store->setAlignment(Alignment.getQuantity());
1698 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) {
1699 CGF.EmitARCDestroyStrong(field, ARCImpreciseLifetime);
1702 void profileImpl(llvm::FoldingSetNodeID &id) const {
1703 // 2 is distinguishable from all pointers and byref flags
1708 /// Emits the copy/dispose helpers for a __block variable with a
1709 /// nontrivial copy constructor or destructor.
1710 class CXXByrefHelpers : public CodeGenModule::ByrefHelpers {
1712 const Expr *CopyExpr;
1715 CXXByrefHelpers(CharUnits alignment, QualType type,
1716 const Expr *copyExpr)
1717 : ByrefHelpers(alignment), VarType(type), CopyExpr(copyExpr) {}
1719 bool needsCopy() const { return CopyExpr != 0; }
1720 void emitCopy(CodeGenFunction &CGF, llvm::Value *destField,
1721 llvm::Value *srcField) {
1722 if (!CopyExpr) return;
1723 CGF.EmitSynthesizedCXXCopyCtor(destField, srcField, CopyExpr);
1726 void emitDispose(CodeGenFunction &CGF, llvm::Value *field) {
1727 EHScopeStack::stable_iterator cleanupDepth = CGF.EHStack.stable_begin();
1728 CGF.PushDestructorCleanup(VarType, field);
1729 CGF.PopCleanupBlocks(cleanupDepth);
1732 void profileImpl(llvm::FoldingSetNodeID &id) const {
1733 id.AddPointer(VarType.getCanonicalType().getAsOpaquePtr());
1736 } // end anonymous namespace
1738 static llvm::Constant *
1739 generateByrefCopyHelper(CodeGenFunction &CGF,
1740 llvm::StructType &byrefType,
1741 unsigned valueFieldIndex,
1742 CodeGenModule::ByrefHelpers &byrefInfo) {
1743 ASTContext &Context = CGF.getContext();
1745 QualType R = Context.VoidTy;
1747 FunctionArgList args;
1748 ImplicitParamDecl dst(0, SourceLocation(), 0, Context.VoidPtrTy);
1749 args.push_back(&dst);
1751 ImplicitParamDecl src(0, SourceLocation(), 0, Context.VoidPtrTy);
1752 args.push_back(&src);
1754 const CGFunctionInfo &FI =
1755 CGF.CGM.getTypes().arrangeFunctionDeclaration(R, args,
1756 FunctionType::ExtInfo(),
1757 /*variadic*/ false);
1759 CodeGenTypes &Types = CGF.CGM.getTypes();
1760 llvm::FunctionType *LTy = Types.GetFunctionType(FI);
1762 // FIXME: We'd like to put these into a mergable by content, with
1763 // internal linkage.
1764 llvm::Function *Fn =
1765 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
1766 "__Block_byref_object_copy_", &CGF.CGM.getModule());
1769 = &Context.Idents.get("__Block_byref_object_copy_");
1771 FunctionDecl *FD = FunctionDecl::Create(Context,
1772 Context.getTranslationUnitDecl(),
1774 SourceLocation(), II, R, 0,
1778 CGF.StartFunction(FD, R, Fn, FI, args, SourceLocation());
1780 if (byrefInfo.needsCopy()) {
1781 llvm::Type *byrefPtrType = byrefType.getPointerTo(0);
1784 llvm::Value *destField = CGF.GetAddrOfLocalVar(&dst);
1785 destField = CGF.Builder.CreateLoad(destField);
1786 destField = CGF.Builder.CreateBitCast(destField, byrefPtrType);
1787 destField = CGF.Builder.CreateStructGEP(destField, valueFieldIndex, "x");
1790 llvm::Value *srcField = CGF.GetAddrOfLocalVar(&src);
1791 srcField = CGF.Builder.CreateLoad(srcField);
1792 srcField = CGF.Builder.CreateBitCast(srcField, byrefPtrType);
1793 srcField = CGF.Builder.CreateStructGEP(srcField, valueFieldIndex, "x");
1795 byrefInfo.emitCopy(CGF, destField, srcField);
1798 CGF.FinishFunction();
1800 return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy);
1803 /// Build the copy helper for a __block variable.
1804 static llvm::Constant *buildByrefCopyHelper(CodeGenModule &CGM,
1805 llvm::StructType &byrefType,
1806 unsigned byrefValueIndex,
1807 CodeGenModule::ByrefHelpers &info) {
1808 CodeGenFunction CGF(CGM);
1809 return generateByrefCopyHelper(CGF, byrefType, byrefValueIndex, info);
1812 /// Generate code for a __block variable's dispose helper.
1813 static llvm::Constant *
1814 generateByrefDisposeHelper(CodeGenFunction &CGF,
1815 llvm::StructType &byrefType,
1816 unsigned byrefValueIndex,
1817 CodeGenModule::ByrefHelpers &byrefInfo) {
1818 ASTContext &Context = CGF.getContext();
1819 QualType R = Context.VoidTy;
1821 FunctionArgList args;
1822 ImplicitParamDecl src(0, SourceLocation(), 0, Context.VoidPtrTy);
1823 args.push_back(&src);
1825 const CGFunctionInfo &FI =
1826 CGF.CGM.getTypes().arrangeFunctionDeclaration(R, args,
1827 FunctionType::ExtInfo(),
1828 /*variadic*/ false);
1830 CodeGenTypes &Types = CGF.CGM.getTypes();
1831 llvm::FunctionType *LTy = Types.GetFunctionType(FI);
1833 // FIXME: We'd like to put these into a mergable by content, with
1834 // internal linkage.
1835 llvm::Function *Fn =
1836 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
1837 "__Block_byref_object_dispose_",
1838 &CGF.CGM.getModule());
1841 = &Context.Idents.get("__Block_byref_object_dispose_");
1843 FunctionDecl *FD = FunctionDecl::Create(Context,
1844 Context.getTranslationUnitDecl(),
1846 SourceLocation(), II, R, 0,
1849 CGF.StartFunction(FD, R, Fn, FI, args, SourceLocation());
1851 if (byrefInfo.needsDispose()) {
1852 llvm::Value *V = CGF.GetAddrOfLocalVar(&src);
1853 V = CGF.Builder.CreateLoad(V);
1854 V = CGF.Builder.CreateBitCast(V, byrefType.getPointerTo(0));
1855 V = CGF.Builder.CreateStructGEP(V, byrefValueIndex, "x");
1857 byrefInfo.emitDispose(CGF, V);
1860 CGF.FinishFunction();
1862 return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy);
1865 /// Build the dispose helper for a __block variable.
1866 static llvm::Constant *buildByrefDisposeHelper(CodeGenModule &CGM,
1867 llvm::StructType &byrefType,
1868 unsigned byrefValueIndex,
1869 CodeGenModule::ByrefHelpers &info) {
1870 CodeGenFunction CGF(CGM);
1871 return generateByrefDisposeHelper(CGF, byrefType, byrefValueIndex, info);
1874 /// Lazily build the copy and dispose helpers for a __block variable
1875 /// with the given information.
1876 template <class T> static T *buildByrefHelpers(CodeGenModule &CGM,
1877 llvm::StructType &byrefTy,
1878 unsigned byrefValueIndex,
1880 // Increase the field's alignment to be at least pointer alignment,
1881 // since the layout of the byref struct will guarantee at least that.
1882 byrefInfo.Alignment = std::max(byrefInfo.Alignment,
1883 CharUnits::fromQuantity(CGM.PointerAlignInBytes));
1885 llvm::FoldingSetNodeID id;
1886 byrefInfo.Profile(id);
1889 CodeGenModule::ByrefHelpers *node
1890 = CGM.ByrefHelpersCache.FindNodeOrInsertPos(id, insertPos);
1891 if (node) return static_cast<T*>(node);
1893 byrefInfo.CopyHelper =
1894 buildByrefCopyHelper(CGM, byrefTy, byrefValueIndex, byrefInfo);
1895 byrefInfo.DisposeHelper =
1896 buildByrefDisposeHelper(CGM, byrefTy, byrefValueIndex,byrefInfo);
1898 T *copy = new (CGM.getContext()) T(byrefInfo);
1899 CGM.ByrefHelpersCache.InsertNode(copy, insertPos);
1903 /// Build the copy and dispose helpers for the given __block variable
1904 /// emission. Places the helpers in the global cache. Returns null
1905 /// if no helpers are required.
1906 CodeGenModule::ByrefHelpers *
1907 CodeGenFunction::buildByrefHelpers(llvm::StructType &byrefType,
1908 const AutoVarEmission &emission) {
1909 const VarDecl &var = *emission.Variable;
1910 QualType type = var.getType();
1912 unsigned byrefValueIndex = getByRefValueLLVMField(&var);
1914 if (const CXXRecordDecl *record = type->getAsCXXRecordDecl()) {
1915 const Expr *copyExpr = CGM.getContext().getBlockVarCopyInits(&var);
1916 if (!copyExpr && record->hasTrivialDestructor()) return 0;
1918 CXXByrefHelpers byrefInfo(emission.Alignment, type, copyExpr);
1919 return ::buildByrefHelpers(CGM, byrefType, byrefValueIndex, byrefInfo);
1922 // Otherwise, if we don't have a retainable type, there's nothing to do.
1923 // that the runtime does extra copies.
1924 if (!type->isObjCRetainableType()) return 0;
1926 Qualifiers qs = type.getQualifiers();
1928 // If we have lifetime, that dominates.
1929 if (Qualifiers::ObjCLifetime lifetime = qs.getObjCLifetime()) {
1930 assert(getLangOpts().ObjCAutoRefCount);
1933 case Qualifiers::OCL_None: llvm_unreachable("impossible");
1935 // These are just bits as far as the runtime is concerned.
1936 case Qualifiers::OCL_ExplicitNone:
1937 case Qualifiers::OCL_Autoreleasing:
1940 // Tell the runtime that this is ARC __weak, called by the
1942 case Qualifiers::OCL_Weak: {
1943 ARCWeakByrefHelpers byrefInfo(emission.Alignment);
1944 return ::buildByrefHelpers(CGM, byrefType, byrefValueIndex, byrefInfo);
1947 // ARC __strong __block variables need to be retained.
1948 case Qualifiers::OCL_Strong:
1949 // Block pointers need to be copied, and there's no direct
1950 // transfer possible.
1951 if (type->isBlockPointerType()) {
1952 ARCStrongBlockByrefHelpers byrefInfo(emission.Alignment);
1953 return ::buildByrefHelpers(CGM, byrefType, byrefValueIndex, byrefInfo);
1955 // Otherwise, we transfer ownership of the retain from the stack
1958 ARCStrongByrefHelpers byrefInfo(emission.Alignment);
1959 return ::buildByrefHelpers(CGM, byrefType, byrefValueIndex, byrefInfo);
1962 llvm_unreachable("fell out of lifetime switch!");
1965 BlockFieldFlags flags;
1966 if (type->isBlockPointerType()) {
1967 flags |= BLOCK_FIELD_IS_BLOCK;
1968 } else if (CGM.getContext().isObjCNSObjectType(type) ||
1969 type->isObjCObjectPointerType()) {
1970 flags |= BLOCK_FIELD_IS_OBJECT;
1975 if (type.isObjCGCWeak())
1976 flags |= BLOCK_FIELD_IS_WEAK;
1978 ObjectByrefHelpers byrefInfo(emission.Alignment, flags);
1979 return ::buildByrefHelpers(CGM, byrefType, byrefValueIndex, byrefInfo);
1982 unsigned CodeGenFunction::getByRefValueLLVMField(const ValueDecl *VD) const {
1983 assert(ByRefValueInfo.count(VD) && "Did not find value!");
1985 return ByRefValueInfo.find(VD)->second.second;
1988 llvm::Value *CodeGenFunction::BuildBlockByrefAddress(llvm::Value *BaseAddr,
1990 llvm::Value *Loc = Builder.CreateStructGEP(BaseAddr, 1, "forwarding");
1991 Loc = Builder.CreateLoad(Loc);
1992 Loc = Builder.CreateStructGEP(Loc, getByRefValueLLVMField(V),
1993 V->getNameAsString());
1997 /// BuildByRefType - This routine changes a __block variable declared as T x
2002 /// void *__forwarding;
2003 /// int32_t __flags;
2005 /// void *__copy_helper; // only if needed
2006 /// void *__destroy_helper; // only if needed
2007 /// void *__byref_variable_layout;// only if needed
2008 /// char padding[X]; // only if needed
2012 llvm::Type *CodeGenFunction::BuildByRefType(const VarDecl *D) {
2013 std::pair<llvm::Type *, unsigned> &Info = ByRefValueInfo[D];
2017 QualType Ty = D->getType();
2019 SmallVector<llvm::Type *, 8> types;
2021 llvm::StructType *ByRefType =
2022 llvm::StructType::create(getLLVMContext(),
2023 "struct.__block_byref_" + D->getNameAsString());
2026 types.push_back(Int8PtrTy);
2028 // void *__forwarding;
2029 types.push_back(llvm::PointerType::getUnqual(ByRefType));
2032 types.push_back(Int32Ty);
2035 types.push_back(Int32Ty);
2036 // Note that this must match *exactly* the logic in buildByrefHelpers.
2037 bool HasCopyAndDispose = getContext().BlockRequiresCopying(Ty, D);
2038 if (HasCopyAndDispose) {
2039 /// void *__copy_helper;
2040 types.push_back(Int8PtrTy);
2042 /// void *__destroy_helper;
2043 types.push_back(Int8PtrTy);
2045 bool HasByrefExtendedLayout = false;
2046 Qualifiers::ObjCLifetime Lifetime;
2047 if (getContext().getByrefLifetime(Ty, Lifetime, HasByrefExtendedLayout) &&
2048 HasByrefExtendedLayout)
2049 /// void *__byref_variable_layout;
2050 types.push_back(Int8PtrTy);
2052 bool Packed = false;
2053 CharUnits Align = getContext().getDeclAlign(D);
2055 getContext().toCharUnitsFromBits(getTarget().getPointerAlign(0))) {
2056 // We have to insert padding.
2058 // The struct above has 2 32-bit integers.
2059 unsigned CurrentOffsetInBytes = 4 * 2;
2061 // And either 2, 3, 4 or 5 pointers.
2062 unsigned noPointers = 2;
2063 if (HasCopyAndDispose)
2065 if (HasByrefExtendedLayout)
2068 CurrentOffsetInBytes += noPointers * CGM.getDataLayout().getTypeAllocSize(Int8PtrTy);
2070 // Align the offset.
2071 unsigned AlignedOffsetInBytes =
2072 llvm::RoundUpToAlignment(CurrentOffsetInBytes, Align.getQuantity());
2074 unsigned NumPaddingBytes = AlignedOffsetInBytes - CurrentOffsetInBytes;
2075 if (NumPaddingBytes > 0) {
2076 llvm::Type *Ty = Int8Ty;
2077 // FIXME: We need a sema error for alignment larger than the minimum of
2078 // the maximal stack alignment and the alignment of malloc on the system.
2079 if (NumPaddingBytes > 1)
2080 Ty = llvm::ArrayType::get(Ty, NumPaddingBytes);
2082 types.push_back(Ty);
2084 // We want a packed struct.
2090 types.push_back(ConvertTypeForMem(Ty));
2092 ByRefType->setBody(types, Packed);
2094 Info.first = ByRefType;
2096 Info.second = types.size() - 1;
2101 /// Initialize the structural components of a __block variable, i.e.
2102 /// everything but the actual object.
2103 void CodeGenFunction::emitByrefStructureInit(const AutoVarEmission &emission) {
2104 // Find the address of the local.
2105 llvm::Value *addr = emission.Address;
2107 // That's an alloca of the byref structure type.
2108 llvm::StructType *byrefType = cast<llvm::StructType>(
2109 cast<llvm::PointerType>(addr->getType())->getElementType());
2111 // Build the byref helpers if necessary. This is null if we don't need any.
2112 CodeGenModule::ByrefHelpers *helpers =
2113 buildByrefHelpers(*byrefType, emission);
2115 const VarDecl &D = *emission.Variable;
2116 QualType type = D.getType();
2118 bool HasByrefExtendedLayout;
2119 Qualifiers::ObjCLifetime ByrefLifetime;
2120 bool ByRefHasLifetime =
2121 getContext().getByrefLifetime(type, ByrefLifetime, HasByrefExtendedLayout);
2125 // Initialize the 'isa', which is just 0 or 1.
2127 if (type.isObjCGCWeak())
2129 V = Builder.CreateIntToPtr(Builder.getInt32(isa), Int8PtrTy, "isa");
2130 Builder.CreateStore(V, Builder.CreateStructGEP(addr, 0, "byref.isa"));
2132 // Store the address of the variable into its own forwarding pointer.
2133 Builder.CreateStore(addr,
2134 Builder.CreateStructGEP(addr, 1, "byref.forwarding"));
2137 // c) the flags field is set to either 0 if no helper functions are
2138 // needed or BLOCK_BYREF_HAS_COPY_DISPOSE if they are,
2140 if (helpers) flags |= BLOCK_BYREF_HAS_COPY_DISPOSE;
2141 if (ByRefHasLifetime) {
2142 if (HasByrefExtendedLayout) flags |= BLOCK_BYREF_LAYOUT_EXTENDED;
2143 else switch (ByrefLifetime) {
2144 case Qualifiers::OCL_Strong:
2145 flags |= BLOCK_BYREF_LAYOUT_STRONG;
2147 case Qualifiers::OCL_Weak:
2148 flags |= BLOCK_BYREF_LAYOUT_WEAK;
2150 case Qualifiers::OCL_ExplicitNone:
2151 flags |= BLOCK_BYREF_LAYOUT_UNRETAINED;
2153 case Qualifiers::OCL_None:
2154 if (!type->isObjCObjectPointerType() && !type->isBlockPointerType())
2155 flags |= BLOCK_BYREF_LAYOUT_NON_OBJECT;
2160 if (CGM.getLangOpts().ObjCGCBitmapPrint) {
2161 printf("\n Inline flag for BYREF variable layout (%d):", flags.getBitMask());
2162 if (flags & BLOCK_BYREF_HAS_COPY_DISPOSE)
2163 printf(" BLOCK_BYREF_HAS_COPY_DISPOSE");
2164 if (flags & BLOCK_BYREF_LAYOUT_MASK) {
2165 BlockFlags ThisFlag(flags.getBitMask() & BLOCK_BYREF_LAYOUT_MASK);
2166 if (ThisFlag == BLOCK_BYREF_LAYOUT_EXTENDED)
2167 printf(" BLOCK_BYREF_LAYOUT_EXTENDED");
2168 if (ThisFlag == BLOCK_BYREF_LAYOUT_STRONG)
2169 printf(" BLOCK_BYREF_LAYOUT_STRONG");
2170 if (ThisFlag == BLOCK_BYREF_LAYOUT_WEAK)
2171 printf(" BLOCK_BYREF_LAYOUT_WEAK");
2172 if (ThisFlag == BLOCK_BYREF_LAYOUT_UNRETAINED)
2173 printf(" BLOCK_BYREF_LAYOUT_UNRETAINED");
2174 if (ThisFlag == BLOCK_BYREF_LAYOUT_NON_OBJECT)
2175 printf(" BLOCK_BYREF_LAYOUT_NON_OBJECT");
2181 Builder.CreateStore(llvm::ConstantInt::get(IntTy, flags.getBitMask()),
2182 Builder.CreateStructGEP(addr, 2, "byref.flags"));
2184 CharUnits byrefSize = CGM.GetTargetTypeStoreSize(byrefType);
2185 V = llvm::ConstantInt::get(IntTy, byrefSize.getQuantity());
2186 Builder.CreateStore(V, Builder.CreateStructGEP(addr, 3, "byref.size"));
2189 llvm::Value *copy_helper = Builder.CreateStructGEP(addr, 4);
2190 Builder.CreateStore(helpers->CopyHelper, copy_helper);
2192 llvm::Value *destroy_helper = Builder.CreateStructGEP(addr, 5);
2193 Builder.CreateStore(helpers->DisposeHelper, destroy_helper);
2195 if (ByRefHasLifetime && HasByrefExtendedLayout) {
2196 llvm::Constant* ByrefLayoutInfo = CGM.getObjCRuntime().BuildByrefLayout(CGM, type);
2197 llvm::Value *ByrefInfoAddr = Builder.CreateStructGEP(addr, helpers ? 6 : 4,
2199 // cast destination to pointer to source type.
2200 llvm::Type *DesTy = ByrefLayoutInfo->getType();
2201 DesTy = DesTy->getPointerTo();
2202 llvm::Value *BC = Builder.CreatePointerCast(ByrefInfoAddr, DesTy);
2203 Builder.CreateStore(ByrefLayoutInfo, BC);
2207 void CodeGenFunction::BuildBlockRelease(llvm::Value *V, BlockFieldFlags flags) {
2208 llvm::Value *F = CGM.getBlockObjectDispose();
2209 llvm::Value *args[] = {
2210 Builder.CreateBitCast(V, Int8PtrTy),
2211 llvm::ConstantInt::get(Int32Ty, flags.getBitMask())
2213 EmitNounwindRuntimeCall(F, args); // FIXME: throwing destructors?
2217 struct CallBlockRelease : EHScopeStack::Cleanup {
2219 CallBlockRelease(llvm::Value *Addr) : Addr(Addr) {}
2221 void Emit(CodeGenFunction &CGF, Flags flags) {
2222 // Should we be passing FIELD_IS_WEAK here?
2223 CGF.BuildBlockRelease(Addr, BLOCK_FIELD_IS_BYREF);
2228 /// Enter a cleanup to destroy a __block variable. Note that this
2229 /// cleanup should be a no-op if the variable hasn't left the stack
2230 /// yet; if a cleanup is required for the variable itself, that needs
2231 /// to be done externally.
2232 void CodeGenFunction::enterByrefCleanup(const AutoVarEmission &emission) {
2233 // We don't enter this cleanup if we're in pure-GC mode.
2234 if (CGM.getLangOpts().getGC() == LangOptions::GCOnly)
2237 EHStack.pushCleanup<CallBlockRelease>(NormalAndEHCleanup, emission.Address);
2240 /// Adjust the declaration of something from the blocks API.
2241 static void configureBlocksRuntimeObject(CodeGenModule &CGM,
2242 llvm::Constant *C) {
2243 if (!CGM.getLangOpts().BlocksRuntimeOptional) return;
2245 llvm::GlobalValue *GV = cast<llvm::GlobalValue>(C->stripPointerCasts());
2246 if (GV->isDeclaration() &&
2247 GV->getLinkage() == llvm::GlobalValue::ExternalLinkage)
2248 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
2251 llvm::Constant *CodeGenModule::getBlockObjectDispose() {
2252 if (BlockObjectDispose)
2253 return BlockObjectDispose;
2255 llvm::Type *args[] = { Int8PtrTy, Int32Ty };
2256 llvm::FunctionType *fty
2257 = llvm::FunctionType::get(VoidTy, args, false);
2258 BlockObjectDispose = CreateRuntimeFunction(fty, "_Block_object_dispose");
2259 configureBlocksRuntimeObject(*this, BlockObjectDispose);
2260 return BlockObjectDispose;
2263 llvm::Constant *CodeGenModule::getBlockObjectAssign() {
2264 if (BlockObjectAssign)
2265 return BlockObjectAssign;
2267 llvm::Type *args[] = { Int8PtrTy, Int8PtrTy, Int32Ty };
2268 llvm::FunctionType *fty
2269 = llvm::FunctionType::get(VoidTy, args, false);
2270 BlockObjectAssign = CreateRuntimeFunction(fty, "_Block_object_assign");
2271 configureBlocksRuntimeObject(*this, BlockObjectAssign);
2272 return BlockObjectAssign;
2275 llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() {
2276 if (NSConcreteGlobalBlock)
2277 return NSConcreteGlobalBlock;
2279 NSConcreteGlobalBlock = GetOrCreateLLVMGlobal("_NSConcreteGlobalBlock",
2280 Int8PtrTy->getPointerTo(), 0);
2281 configureBlocksRuntimeObject(*this, NSConcreteGlobalBlock);
2282 return NSConcreteGlobalBlock;
2285 llvm::Constant *CodeGenModule::getNSConcreteStackBlock() {
2286 if (NSConcreteStackBlock)
2287 return NSConcreteStackBlock;
2289 NSConcreteStackBlock = GetOrCreateLLVMGlobal("_NSConcreteStackBlock",
2290 Int8PtrTy->getPointerTo(), 0);
2291 configureBlocksRuntimeObject(*this, NSConcreteStackBlock);
2292 return NSConcreteStackBlock;