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 "CGOpenCLRuntime.h"
18 #include "CodeGenFunction.h"
19 #include "CodeGenModule.h"
20 #include "ConstantEmitter.h"
21 #include "TargetInfo.h"
22 #include "clang/AST/DeclObjC.h"
23 #include "clang/CodeGen/ConstantInitBuilder.h"
24 #include "llvm/ADT/SmallSet.h"
25 #include "llvm/IR/CallSite.h"
26 #include "llvm/IR/DataLayout.h"
27 #include "llvm/IR/Module.h"
31 using namespace clang;
32 using namespace CodeGen;
34 CGBlockInfo::CGBlockInfo(const BlockDecl *block, StringRef name)
35 : Name(name), CXXThisIndex(0), CanBeGlobal(false), NeedsCopyDispose(false),
36 HasCXXObject(false), UsesStret(false), HasCapturedVariableLayout(false),
37 LocalAddress(Address::invalid()), StructureType(nullptr), Block(block),
38 DominatingIP(nullptr) {
40 // Skip asm prefix, if any. 'name' is usually taken directly from
41 // the mangled name of the enclosing function.
42 if (!name.empty() && name[0] == '\01')
43 name = name.substr(1);
46 // Anchor the vtable to this translation unit.
47 BlockByrefHelpers::~BlockByrefHelpers() {}
49 /// Build the given block as a global block.
50 static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
51 const CGBlockInfo &blockInfo,
52 llvm::Constant *blockFn);
54 /// Build the helper function to copy a block.
55 static llvm::Constant *buildCopyHelper(CodeGenModule &CGM,
56 const CGBlockInfo &blockInfo) {
57 return CodeGenFunction(CGM).GenerateCopyHelperFunction(blockInfo);
60 /// Build the helper function to dispose of a block.
61 static llvm::Constant *buildDisposeHelper(CodeGenModule &CGM,
62 const CGBlockInfo &blockInfo) {
63 return CodeGenFunction(CGM).GenerateDestroyHelperFunction(blockInfo);
66 /// buildBlockDescriptor - Build the block descriptor meta-data for a block.
67 /// buildBlockDescriptor is accessed from 5th field of the Block_literal
68 /// meta-data and contains stationary information about the block literal.
69 /// Its definition will have 4 (or optionally 6) words.
71 /// struct Block_descriptor {
72 /// unsigned long reserved;
73 /// unsigned long size; // size of Block_literal metadata in bytes.
74 /// void *copy_func_helper_decl; // optional copy helper.
75 /// void *destroy_func_decl; // optioanl destructor helper.
76 /// void *block_method_encoding_address; // @encode for block literal signature.
77 /// void *block_layout_info; // encoding of captured block variables.
80 static llvm::Constant *buildBlockDescriptor(CodeGenModule &CGM,
81 const CGBlockInfo &blockInfo) {
82 ASTContext &C = CGM.getContext();
84 llvm::IntegerType *ulong =
85 cast<llvm::IntegerType>(CGM.getTypes().ConvertType(C.UnsignedLongTy));
86 llvm::PointerType *i8p = nullptr;
87 if (CGM.getLangOpts().OpenCL)
89 llvm::Type::getInt8PtrTy(
90 CGM.getLLVMContext(), C.getTargetAddressSpace(LangAS::opencl_constant));
94 ConstantInitBuilder builder(CGM);
95 auto elements = builder.beginStruct();
98 elements.addInt(ulong, 0);
101 // FIXME: What is the right way to say this doesn't fit? We should give
102 // a user diagnostic in that case. Better fix would be to change the
104 elements.addInt(ulong, blockInfo.BlockSize.getQuantity());
106 // Optional copy/dispose helpers.
107 if (blockInfo.needsCopyDisposeHelpers()) {
108 // copy_func_helper_decl
109 elements.add(buildCopyHelper(CGM, blockInfo));
112 elements.add(buildDisposeHelper(CGM, blockInfo));
115 // Signature. Mandatory ObjC-style method descriptor @encode sequence.
116 std::string typeAtEncoding =
117 CGM.getContext().getObjCEncodingForBlock(blockInfo.getBlockExpr());
118 elements.add(llvm::ConstantExpr::getBitCast(
119 CGM.GetAddrOfConstantCString(typeAtEncoding).getPointer(), i8p));
122 if (C.getLangOpts().ObjC1) {
123 if (CGM.getLangOpts().getGC() != LangOptions::NonGC)
124 elements.add(CGM.getObjCRuntime().BuildGCBlockLayout(CGM, blockInfo));
126 elements.add(CGM.getObjCRuntime().BuildRCBlockLayout(CGM, blockInfo));
129 elements.addNullPointer(i8p);
131 unsigned AddrSpace = 0;
132 if (C.getLangOpts().OpenCL)
133 AddrSpace = C.getTargetAddressSpace(LangAS::opencl_constant);
135 llvm::GlobalVariable *global =
136 elements.finishAndCreateGlobal("__block_descriptor_tmp",
137 CGM.getPointerAlign(),
139 llvm::GlobalValue::InternalLinkage,
142 return llvm::ConstantExpr::getBitCast(global, CGM.getBlockDescriptorType());
146 Purely notional variadic template describing the layout of a block.
148 template <class _ResultType, class... _ParamTypes, class... _CaptureTypes>
149 struct Block_literal {
150 /// Initialized to one of:
151 /// extern void *_NSConcreteStackBlock[];
152 /// extern void *_NSConcreteGlobalBlock[];
154 /// In theory, we could start one off malloc'ed by setting
155 /// BLOCK_NEEDS_FREE, giving it a refcount of 1, and using
157 /// extern void *_NSConcreteMallocBlock[];
158 struct objc_class *isa;
160 /// These are the flags (with corresponding bit number) that the
161 /// compiler is actually supposed to know about.
162 /// 23. BLOCK_IS_NOESCAPE - indicates that the block is non-escaping
163 /// 25. BLOCK_HAS_COPY_DISPOSE - indicates that the block
164 /// descriptor provides copy and dispose helper functions
165 /// 26. BLOCK_HAS_CXX_OBJ - indicates that there's a captured
166 /// object with a nontrivial destructor or copy constructor
167 /// 28. BLOCK_IS_GLOBAL - indicates that the block is allocated
169 /// 29. BLOCK_USE_STRET - indicates that the block function
170 /// uses stret, which objc_msgSend needs to know about
171 /// 30. BLOCK_HAS_SIGNATURE - indicates that the block has an
172 /// @encoded signature string
173 /// And we're not supposed to manipulate these:
174 /// 24. BLOCK_NEEDS_FREE - indicates that the block has been moved
175 /// to malloc'ed memory
176 /// 27. BLOCK_IS_GC - indicates that the block has been moved to
177 /// to GC-allocated memory
178 /// Additionally, the bottom 16 bits are a reference count which
179 /// should be zero on the stack.
182 /// Reserved; should be zero-initialized.
185 /// Function pointer generated from block literal.
186 _ResultType (*invoke)(Block_literal *, _ParamTypes...);
188 /// Block description metadata generated from block literal.
189 struct Block_descriptor *block_descriptor;
191 /// Captured values follow.
192 _CapturesTypes captures...;
197 /// A chunk of data that we actually have to capture in the block.
198 struct BlockLayoutChunk {
201 Qualifiers::ObjCLifetime Lifetime;
202 const BlockDecl::Capture *Capture; // null for 'this'
206 BlockLayoutChunk(CharUnits align, CharUnits size,
207 Qualifiers::ObjCLifetime lifetime,
208 const BlockDecl::Capture *capture,
209 llvm::Type *type, QualType fieldType)
210 : Alignment(align), Size(size), Lifetime(lifetime),
211 Capture(capture), Type(type), FieldType(fieldType) {}
213 /// Tell the block info that this chunk has the given field index.
214 void setIndex(CGBlockInfo &info, unsigned index, CharUnits offset) {
216 info.CXXThisIndex = index;
217 info.CXXThisOffset = offset;
219 auto C = CGBlockInfo::Capture::makeIndex(index, offset, FieldType);
220 info.Captures.insert({Capture->getVariable(), C});
225 /// Order by 1) all __strong together 2) next, all byfref together 3) next,
226 /// all __weak together. Preserve descending alignment in all situations.
227 bool operator<(const BlockLayoutChunk &left, const BlockLayoutChunk &right) {
228 if (left.Alignment != right.Alignment)
229 return left.Alignment > right.Alignment;
231 auto getPrefOrder = [](const BlockLayoutChunk &chunk) {
232 if (chunk.Capture && chunk.Capture->isByRef())
234 if (chunk.Lifetime == Qualifiers::OCL_Strong)
236 if (chunk.Lifetime == Qualifiers::OCL_Weak)
241 return getPrefOrder(left) < getPrefOrder(right);
243 } // end anonymous namespace
245 /// Determines if the given type is safe for constant capture in C++.
246 static bool isSafeForCXXConstantCapture(QualType type) {
247 const RecordType *recordType =
248 type->getBaseElementTypeUnsafe()->getAs<RecordType>();
250 // Only records can be unsafe.
251 if (!recordType) return true;
253 const auto *record = cast<CXXRecordDecl>(recordType->getDecl());
255 // Maintain semantics for classes with non-trivial dtors or copy ctors.
256 if (!record->hasTrivialDestructor()) return false;
257 if (record->hasNonTrivialCopyConstructor()) return false;
259 // Otherwise, we just have to make sure there aren't any mutable
260 // fields that might have changed since initialization.
261 return !record->hasMutableFields();
264 /// It is illegal to modify a const object after initialization.
265 /// Therefore, if a const object has a constant initializer, we don't
266 /// actually need to keep storage for it in the block; we'll just
267 /// rematerialize it at the start of the block function. This is
268 /// acceptable because we make no promises about address stability of
269 /// captured variables.
270 static llvm::Constant *tryCaptureAsConstant(CodeGenModule &CGM,
271 CodeGenFunction *CGF,
272 const VarDecl *var) {
273 // Return if this is a function parameter. We shouldn't try to
274 // rematerialize default arguments of function parameters.
275 if (isa<ParmVarDecl>(var))
278 QualType type = var->getType();
280 // We can only do this if the variable is const.
281 if (!type.isConstQualified()) return nullptr;
283 // Furthermore, in C++ we have to worry about mutable fields:
284 // C++ [dcl.type.cv]p4:
285 // Except that any class member declared mutable can be
286 // modified, any attempt to modify a const object during its
287 // lifetime results in undefined behavior.
288 if (CGM.getLangOpts().CPlusPlus && !isSafeForCXXConstantCapture(type))
291 // If the variable doesn't have any initializer (shouldn't this be
292 // invalid?), it's not clear what we should do. Maybe capture as
294 const Expr *init = var->getInit();
295 if (!init) return nullptr;
297 return ConstantEmitter(CGM, CGF).tryEmitAbstractForInitializer(*var);
300 /// Get the low bit of a nonzero character count. This is the
301 /// alignment of the nth byte if the 0th byte is universally aligned.
302 static CharUnits getLowBit(CharUnits v) {
303 return CharUnits::fromQuantity(v.getQuantity() & (~v.getQuantity() + 1));
306 static void initializeForBlockHeader(CodeGenModule &CGM, CGBlockInfo &info,
307 SmallVectorImpl<llvm::Type*> &elementTypes) {
309 assert(elementTypes.empty());
310 if (CGM.getLangOpts().OpenCL) {
311 // The header is basically 'struct { int; int;
312 // custom_fields; }'. Assert that struct is packed.
313 elementTypes.push_back(CGM.IntTy); /* total size */
314 elementTypes.push_back(CGM.IntTy); /* align */
315 unsigned Offset = 2 * CGM.getIntSize().getQuantity();
316 unsigned BlockAlign = CGM.getIntAlign().getQuantity();
318 CGM.getTargetCodeGenInfo().getTargetOpenCLBlockHelper()) {
319 for (auto I : Helper->getCustomFieldTypes()) /* custom fields */ {
320 // TargetOpenCLBlockHelp needs to make sure the struct is packed.
321 // If necessary, add padding fields to the custom fields.
322 unsigned Align = CGM.getDataLayout().getABITypeAlignment(I);
323 if (BlockAlign < Align)
325 assert(Offset % Align == 0);
326 Offset += CGM.getDataLayout().getTypeAllocSize(I);
327 elementTypes.push_back(I);
330 info.BlockAlign = CharUnits::fromQuantity(BlockAlign);
331 info.BlockSize = CharUnits::fromQuantity(Offset);
333 // The header is basically 'struct { void *; int; int; void *; void *; }'.
334 // Assert that the struct is packed.
335 assert(CGM.getIntSize() <= CGM.getPointerSize());
336 assert(CGM.getIntAlign() <= CGM.getPointerAlign());
337 assert((2 * CGM.getIntSize()).isMultipleOf(CGM.getPointerAlign()));
338 info.BlockAlign = CGM.getPointerAlign();
339 info.BlockSize = 3 * CGM.getPointerSize() + 2 * CGM.getIntSize();
340 elementTypes.push_back(CGM.VoidPtrTy);
341 elementTypes.push_back(CGM.IntTy);
342 elementTypes.push_back(CGM.IntTy);
343 elementTypes.push_back(CGM.VoidPtrTy);
344 elementTypes.push_back(CGM.getBlockDescriptorType());
348 static QualType getCaptureFieldType(const CodeGenFunction &CGF,
349 const BlockDecl::Capture &CI) {
350 const VarDecl *VD = CI.getVariable();
352 // If the variable is captured by an enclosing block or lambda expression,
353 // use the type of the capture field.
354 if (CGF.BlockInfo && CI.isNested())
355 return CGF.BlockInfo->getCapture(VD).fieldType();
356 if (auto *FD = CGF.LambdaCaptureFields.lookup(VD))
357 return FD->getType();
358 return VD->getType();
361 /// Compute the layout of the given block. Attempts to lay the block
362 /// out with minimal space requirements.
363 static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF,
365 ASTContext &C = CGM.getContext();
366 const BlockDecl *block = info.getBlockDecl();
368 SmallVector<llvm::Type*, 8> elementTypes;
369 initializeForBlockHeader(CGM, info, elementTypes);
370 bool hasNonConstantCustomFields = false;
371 if (auto *OpenCLHelper =
372 CGM.getTargetCodeGenInfo().getTargetOpenCLBlockHelper())
373 hasNonConstantCustomFields =
374 !OpenCLHelper->areAllCustomFieldValuesConstant(info);
375 if (!block->hasCaptures() && !hasNonConstantCustomFields) {
377 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true);
378 info.CanBeGlobal = true;
381 else if (C.getLangOpts().ObjC1 &&
382 CGM.getLangOpts().getGC() == LangOptions::NonGC)
383 info.HasCapturedVariableLayout = true;
385 // Collect the layout chunks.
386 SmallVector<BlockLayoutChunk, 16> layout;
387 layout.reserve(block->capturesCXXThis() +
388 (block->capture_end() - block->capture_begin()));
390 CharUnits maxFieldAlign;
393 if (block->capturesCXXThis()) {
394 assert(CGF && CGF->CurFuncDecl && isa<CXXMethodDecl>(CGF->CurFuncDecl) &&
395 "Can't capture 'this' outside a method");
396 QualType thisType = cast<CXXMethodDecl>(CGF->CurFuncDecl)->getThisType(C);
398 // Theoretically, this could be in a different address space, so
399 // don't assume standard pointer size/align.
400 llvm::Type *llvmType = CGM.getTypes().ConvertType(thisType);
401 std::pair<CharUnits,CharUnits> tinfo
402 = CGM.getContext().getTypeInfoInChars(thisType);
403 maxFieldAlign = std::max(maxFieldAlign, tinfo.second);
405 layout.push_back(BlockLayoutChunk(tinfo.second, tinfo.first,
406 Qualifiers::OCL_None,
407 nullptr, llvmType, thisType));
410 // Next, all the block captures.
411 for (const auto &CI : block->captures()) {
412 const VarDecl *variable = CI.getVariable();
415 // We have to copy/dispose of the __block reference.
416 info.NeedsCopyDispose = true;
418 // Just use void* instead of a pointer to the byref type.
419 CharUnits align = CGM.getPointerAlign();
420 maxFieldAlign = std::max(maxFieldAlign, align);
422 layout.push_back(BlockLayoutChunk(align, CGM.getPointerSize(),
423 Qualifiers::OCL_None, &CI,
424 CGM.VoidPtrTy, variable->getType()));
428 // Otherwise, build a layout chunk with the size and alignment of
430 if (llvm::Constant *constant = tryCaptureAsConstant(CGM, CGF, variable)) {
431 info.Captures[variable] = CGBlockInfo::Capture::makeConstant(constant);
435 // If we have a lifetime qualifier, honor it for capture purposes.
436 // That includes *not* copying it if it's __unsafe_unretained.
437 Qualifiers::ObjCLifetime lifetime =
438 variable->getType().getObjCLifetime();
441 case Qualifiers::OCL_None: llvm_unreachable("impossible");
442 case Qualifiers::OCL_ExplicitNone:
443 case Qualifiers::OCL_Autoreleasing:
446 case Qualifiers::OCL_Strong:
447 case Qualifiers::OCL_Weak:
448 info.NeedsCopyDispose = true;
451 // Block pointers require copy/dispose. So do Objective-C pointers.
452 } else if (variable->getType()->isObjCRetainableType()) {
453 // But honor the inert __unsafe_unretained qualifier, which doesn't
454 // actually make it into the type system.
455 if (variable->getType()->isObjCInertUnsafeUnretainedType()) {
456 lifetime = Qualifiers::OCL_ExplicitNone;
458 info.NeedsCopyDispose = true;
459 // used for mrr below.
460 lifetime = Qualifiers::OCL_Strong;
463 // So do types that require non-trivial copy construction.
464 } else if (CI.hasCopyExpr()) {
465 info.NeedsCopyDispose = true;
466 info.HasCXXObject = true;
468 // So do C structs that require non-trivial copy construction or
470 } else if (variable->getType().isNonTrivialToPrimitiveCopy() ==
471 QualType::PCK_Struct ||
472 variable->getType().isDestructedType() ==
473 QualType::DK_nontrivial_c_struct) {
474 info.NeedsCopyDispose = true;
476 // And so do types with destructors.
477 } else if (CGM.getLangOpts().CPlusPlus) {
478 if (const CXXRecordDecl *record =
479 variable->getType()->getAsCXXRecordDecl()) {
480 if (!record->hasTrivialDestructor()) {
481 info.HasCXXObject = true;
482 info.NeedsCopyDispose = true;
487 QualType VT = getCaptureFieldType(*CGF, CI);
488 CharUnits size = C.getTypeSizeInChars(VT);
489 CharUnits align = C.getDeclAlign(variable);
491 maxFieldAlign = std::max(maxFieldAlign, align);
493 llvm::Type *llvmType =
494 CGM.getTypes().ConvertTypeForMem(VT);
497 BlockLayoutChunk(align, size, lifetime, &CI, llvmType, VT));
500 // If that was everything, we're done here.
501 if (layout.empty()) {
503 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true);
504 info.CanBeGlobal = true;
508 // Sort the layout by alignment. We have to use a stable sort here
509 // to get reproducible results. There should probably be an
510 // llvm::array_pod_stable_sort.
511 std::stable_sort(layout.begin(), layout.end());
513 // Needed for blocks layout info.
514 info.BlockHeaderForcedGapOffset = info.BlockSize;
515 info.BlockHeaderForcedGapSize = CharUnits::Zero();
517 CharUnits &blockSize = info.BlockSize;
518 info.BlockAlign = std::max(maxFieldAlign, info.BlockAlign);
520 // Assuming that the first byte in the header is maximally aligned,
521 // get the alignment of the first byte following the header.
522 CharUnits endAlign = getLowBit(blockSize);
524 // If the end of the header isn't satisfactorily aligned for the
525 // maximum thing, look for things that are okay with the header-end
526 // alignment, and keep appending them until we get something that's
527 // aligned right. This algorithm is only guaranteed optimal if
528 // that condition is satisfied at some point; otherwise we can get
530 // header // next byte has alignment 4
531 // something_with_size_5; // next byte has alignment 1
532 // something_with_alignment_8;
533 // which has 7 bytes of padding, as opposed to the naive solution
534 // which might have less (?).
535 if (endAlign < maxFieldAlign) {
536 SmallVectorImpl<BlockLayoutChunk>::iterator
537 li = layout.begin() + 1, le = layout.end();
539 // Look for something that the header end is already
540 // satisfactorily aligned for.
541 for (; li != le && endAlign < li->Alignment; ++li)
544 // If we found something that's naturally aligned for the end of
545 // the header, keep adding things...
547 SmallVectorImpl<BlockLayoutChunk>::iterator first = li;
548 for (; li != le; ++li) {
549 assert(endAlign >= li->Alignment);
551 li->setIndex(info, elementTypes.size(), blockSize);
552 elementTypes.push_back(li->Type);
553 blockSize += li->Size;
554 endAlign = getLowBit(blockSize);
556 // ...until we get to the alignment of the maximum field.
557 if (endAlign >= maxFieldAlign) {
561 // Don't re-append everything we just appended.
562 layout.erase(first, li);
566 assert(endAlign == getLowBit(blockSize));
568 // At this point, we just have to add padding if the end align still
569 // isn't aligned right.
570 if (endAlign < maxFieldAlign) {
571 CharUnits newBlockSize = blockSize.alignTo(maxFieldAlign);
572 CharUnits padding = newBlockSize - blockSize;
574 // If we haven't yet added any fields, remember that there was an
575 // initial gap; this need to go into the block layout bit map.
576 if (blockSize == info.BlockHeaderForcedGapOffset) {
577 info.BlockHeaderForcedGapSize = padding;
580 elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty,
581 padding.getQuantity()));
582 blockSize = newBlockSize;
583 endAlign = getLowBit(blockSize); // might be > maxFieldAlign
586 assert(endAlign >= maxFieldAlign);
587 assert(endAlign == getLowBit(blockSize));
588 // Slam everything else on now. This works because they have
589 // strictly decreasing alignment and we expect that size is always a
590 // multiple of alignment.
591 for (SmallVectorImpl<BlockLayoutChunk>::iterator
592 li = layout.begin(), le = layout.end(); li != le; ++li) {
593 if (endAlign < li->Alignment) {
594 // size may not be multiple of alignment. This can only happen with
595 // an over-aligned variable. We will be adding a padding field to
596 // make the size be multiple of alignment.
597 CharUnits padding = li->Alignment - endAlign;
598 elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty,
599 padding.getQuantity()));
600 blockSize += padding;
601 endAlign = getLowBit(blockSize);
603 assert(endAlign >= li->Alignment);
604 li->setIndex(info, elementTypes.size(), blockSize);
605 elementTypes.push_back(li->Type);
606 blockSize += li->Size;
607 endAlign = getLowBit(blockSize);
611 llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true);
614 /// Enter the scope of a block. This should be run at the entrance to
615 /// a full-expression so that the block's cleanups are pushed at the
616 /// right place in the stack.
617 static void enterBlockScope(CodeGenFunction &CGF, BlockDecl *block) {
618 assert(CGF.HaveInsertPoint());
620 // Allocate the block info and place it at the head of the list.
621 CGBlockInfo &blockInfo =
622 *new CGBlockInfo(block, CGF.CurFn->getName());
623 blockInfo.NextBlockInfo = CGF.FirstBlockInfo;
624 CGF.FirstBlockInfo = &blockInfo;
626 // Compute information about the layout, etc., of this block,
627 // pushing cleanups as necessary.
628 computeBlockInfo(CGF.CGM, &CGF, blockInfo);
630 // Nothing else to do if it can be global.
631 if (blockInfo.CanBeGlobal) return;
633 // Make the allocation for the block.
634 blockInfo.LocalAddress = CGF.CreateTempAlloca(blockInfo.StructureType,
635 blockInfo.BlockAlign, "block");
637 // If there are cleanups to emit, enter them (but inactive).
638 if (!blockInfo.NeedsCopyDispose) return;
640 // Walk through the captures (in order) and find the ones not
641 // captured by constant.
642 for (const auto &CI : block->captures()) {
643 // Ignore __block captures; there's nothing special in the
644 // on-stack block that we need to do for them.
645 if (CI.isByRef()) continue;
647 // Ignore variables that are constant-captured.
648 const VarDecl *variable = CI.getVariable();
649 CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
650 if (capture.isConstant()) continue;
652 // Ignore objects that aren't destructed.
653 QualType VT = getCaptureFieldType(CGF, CI);
654 QualType::DestructionKind dtorKind = VT.isDestructedType();
655 if (dtorKind == QualType::DK_none) continue;
657 CodeGenFunction::Destroyer *destroyer;
659 // Block captures count as local values and have imprecise semantics.
660 // They also can't be arrays, so need to worry about that.
662 // For const-qualified captures, emit clang.arc.use to ensure the captured
663 // object doesn't get released while we are still depending on its validity
665 if (VT.isConstQualified() &&
666 VT.getObjCLifetime() == Qualifiers::OCL_Strong &&
667 CGF.CGM.getCodeGenOpts().OptimizationLevel != 0) {
668 assert(CGF.CGM.getLangOpts().ObjCAutoRefCount &&
669 "expected ObjC ARC to be enabled");
670 destroyer = CodeGenFunction::emitARCIntrinsicUse;
671 } else if (dtorKind == QualType::DK_objc_strong_lifetime) {
672 destroyer = CodeGenFunction::destroyARCStrongImprecise;
674 destroyer = CGF.getDestroyer(dtorKind);
677 // GEP down to the address.
678 Address addr = CGF.Builder.CreateStructGEP(blockInfo.LocalAddress,
680 capture.getOffset());
682 // We can use that GEP as the dominating IP.
683 if (!blockInfo.DominatingIP)
684 blockInfo.DominatingIP = cast<llvm::Instruction>(addr.getPointer());
686 CleanupKind cleanupKind = InactiveNormalCleanup;
687 bool useArrayEHCleanup = CGF.needsEHCleanup(dtorKind);
688 if (useArrayEHCleanup)
689 cleanupKind = InactiveNormalAndEHCleanup;
691 CGF.pushDestroy(cleanupKind, addr, VT,
692 destroyer, useArrayEHCleanup);
694 // Remember where that cleanup was.
695 capture.setCleanup(CGF.EHStack.stable_begin());
699 /// Enter a full-expression with a non-trivial number of objects to
700 /// clean up. This is in this file because, at the moment, the only
701 /// kind of cleanup object is a BlockDecl*.
702 void CodeGenFunction::enterNonTrivialFullExpression(const ExprWithCleanups *E) {
703 assert(E->getNumObjects() != 0);
704 for (const ExprWithCleanups::CleanupObject &C : E->getObjects())
705 enterBlockScope(*this, C);
708 /// Find the layout for the given block in a linked list and remove it.
709 static CGBlockInfo *findAndRemoveBlockInfo(CGBlockInfo **head,
710 const BlockDecl *block) {
712 assert(head && *head);
713 CGBlockInfo *cur = *head;
715 // If this is the block we're looking for, splice it out of the list.
716 if (cur->getBlockDecl() == block) {
717 *head = cur->NextBlockInfo;
721 head = &cur->NextBlockInfo;
725 /// Destroy a chain of block layouts.
726 void CodeGenFunction::destroyBlockInfos(CGBlockInfo *head) {
727 assert(head && "destroying an empty chain");
729 CGBlockInfo *cur = head;
730 head = cur->NextBlockInfo;
732 } while (head != nullptr);
735 /// Emit a block literal expression in the current function.
736 llvm::Value *CodeGenFunction::EmitBlockLiteral(const BlockExpr *blockExpr) {
737 // If the block has no captures, we won't have a pre-computed
739 if (!blockExpr->getBlockDecl()->hasCaptures()) {
740 // The block literal is emitted as a global variable, and the block invoke
741 // function has to be extracted from its initializer.
742 if (llvm::Constant *Block = CGM.getAddrOfGlobalBlockIfEmitted(blockExpr)) {
745 CGBlockInfo blockInfo(blockExpr->getBlockDecl(), CurFn->getName());
746 computeBlockInfo(CGM, this, blockInfo);
747 blockInfo.BlockExpression = blockExpr;
748 return EmitBlockLiteral(blockInfo);
751 // Find the block info for this block and take ownership of it.
752 std::unique_ptr<CGBlockInfo> blockInfo;
753 blockInfo.reset(findAndRemoveBlockInfo(&FirstBlockInfo,
754 blockExpr->getBlockDecl()));
756 blockInfo->BlockExpression = blockExpr;
757 return EmitBlockLiteral(*blockInfo);
760 llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo) {
761 bool IsOpenCL = CGM.getContext().getLangOpts().OpenCL;
762 // Using the computed layout, generate the actual block function.
763 bool isLambdaConv = blockInfo.getBlockDecl()->isConversionFromLambda();
764 CodeGenFunction BlockCGF{CGM, true};
765 BlockCGF.SanOpts = SanOpts;
766 auto *InvokeFn = BlockCGF.GenerateBlockFunction(
767 CurGD, blockInfo, LocalDeclMap, isLambdaConv, blockInfo.CanBeGlobal);
769 // If there is nothing to capture, we can emit this as a global block.
770 if (blockInfo.CanBeGlobal)
771 return CGM.getAddrOfGlobalBlockIfEmitted(blockInfo.BlockExpression);
773 // Otherwise, we have to emit this as a local block.
775 Address blockAddr = blockInfo.LocalAddress;
776 assert(blockAddr.isValid() && "block has no address!");
779 llvm::Constant *descriptor;
782 // If the block is non-escaping, set field 'isa 'to NSConcreteGlobalBlock
783 // and set the BLOCK_IS_GLOBAL bit of field 'flags'. Copying a non-escaping
784 // block just returns the original block and releasing it is a no-op.
785 llvm::Constant *blockISA = blockInfo.getBlockDecl()->doesNotEscape()
786 ? CGM.getNSConcreteGlobalBlock()
787 : CGM.getNSConcreteStackBlock();
788 isa = llvm::ConstantExpr::getBitCast(blockISA, VoidPtrTy);
790 // Build the block descriptor.
791 descriptor = buildBlockDescriptor(CGM, blockInfo);
793 // Compute the initial on-stack block flags.
794 flags = BLOCK_HAS_SIGNATURE;
795 if (blockInfo.HasCapturedVariableLayout)
796 flags |= BLOCK_HAS_EXTENDED_LAYOUT;
797 if (blockInfo.needsCopyDisposeHelpers())
798 flags |= BLOCK_HAS_COPY_DISPOSE;
799 if (blockInfo.HasCXXObject)
800 flags |= BLOCK_HAS_CXX_OBJ;
801 if (blockInfo.UsesStret)
802 flags |= BLOCK_USE_STRET;
803 if (blockInfo.getBlockDecl()->doesNotEscape())
804 flags |= BLOCK_IS_NOESCAPE | BLOCK_IS_GLOBAL;
808 [&](unsigned index, CharUnits offset, const Twine &name) -> Address {
809 return Builder.CreateStructGEP(blockAddr, index, offset, name);
812 [&](llvm::Value *value, unsigned index, CharUnits offset,
814 Builder.CreateStore(value, projectField(index, offset, name));
817 // Initialize the block header.
819 // We assume all the header fields are densely packed.
822 auto addHeaderField =
823 [&](llvm::Value *value, CharUnits size, const Twine &name) {
824 storeField(value, index, offset, name);
830 addHeaderField(isa, getPointerSize(), "block.isa");
831 addHeaderField(llvm::ConstantInt::get(IntTy, flags.getBitMask()),
832 getIntSize(), "block.flags");
833 addHeaderField(llvm::ConstantInt::get(IntTy, 0), getIntSize(),
837 llvm::ConstantInt::get(IntTy, blockInfo.BlockSize.getQuantity()),
838 getIntSize(), "block.size");
840 llvm::ConstantInt::get(IntTy, blockInfo.BlockAlign.getQuantity()),
841 getIntSize(), "block.align");
844 addHeaderField(llvm::ConstantExpr::getBitCast(InvokeFn, VoidPtrTy),
845 getPointerSize(), "block.invoke");
846 addHeaderField(descriptor, getPointerSize(), "block.descriptor");
847 } else if (auto *Helper =
848 CGM.getTargetCodeGenInfo().getTargetOpenCLBlockHelper()) {
849 for (auto I : Helper->getCustomFieldValues(*this, blockInfo)) {
852 CharUnits::fromQuantity(
853 CGM.getDataLayout().getTypeAllocSize(I.first->getType())),
859 // Finally, capture all the values into the block.
860 const BlockDecl *blockDecl = blockInfo.getBlockDecl();
863 if (blockDecl->capturesCXXThis()) {
864 Address addr = projectField(blockInfo.CXXThisIndex, blockInfo.CXXThisOffset,
865 "block.captured-this.addr");
866 Builder.CreateStore(LoadCXXThis(), addr);
869 // Next, captured variables.
870 for (const auto &CI : blockDecl->captures()) {
871 const VarDecl *variable = CI.getVariable();
872 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
874 // Ignore constant captures.
875 if (capture.isConstant()) continue;
877 QualType type = capture.fieldType();
879 // This will be a [[type]]*, except that a byref entry will just be
882 projectField(capture.getIndex(), capture.getOffset(), "block.captured");
884 // Compute the address of the thing we're going to move into the
886 Address src = Address::invalid();
888 if (blockDecl->isConversionFromLambda()) {
889 // The lambda capture in a lambda's conversion-to-block-pointer is
890 // special; we'll simply emit it directly.
891 src = Address::invalid();
892 } else if (CI.isByRef()) {
893 if (BlockInfo && CI.isNested()) {
894 // We need to use the capture from the enclosing block.
895 const CGBlockInfo::Capture &enclosingCapture =
896 BlockInfo->getCapture(variable);
898 // This is a [[type]]*, except that a byref entry will just be an i8**.
899 src = Builder.CreateStructGEP(LoadBlockStruct(),
900 enclosingCapture.getIndex(),
901 enclosingCapture.getOffset(),
902 "block.capture.addr");
904 auto I = LocalDeclMap.find(variable);
905 assert(I != LocalDeclMap.end());
909 DeclRefExpr declRef(const_cast<VarDecl *>(variable),
910 /*RefersToEnclosingVariableOrCapture*/ CI.isNested(),
911 type.getNonReferenceType(), VK_LValue,
913 src = EmitDeclRefLValue(&declRef).getAddress();
916 // For byrefs, we just write the pointer to the byref struct into
917 // the block field. There's no need to chase the forwarding
918 // pointer at this point, since we're building something that will
919 // live a shorter life than the stack byref anyway.
921 // Get a void* that points to the byref struct.
922 llvm::Value *byrefPointer;
924 byrefPointer = Builder.CreateLoad(src, "byref.capture");
926 byrefPointer = Builder.CreateBitCast(src.getPointer(), VoidPtrTy);
928 // Write that void* into the capture field.
929 Builder.CreateStore(byrefPointer, blockField);
931 // If we have a copy constructor, evaluate that into the block field.
932 } else if (const Expr *copyExpr = CI.getCopyExpr()) {
933 if (blockDecl->isConversionFromLambda()) {
934 // If we have a lambda conversion, emit the expression
935 // directly into the block instead.
937 AggValueSlot::forAddr(blockField, Qualifiers(),
938 AggValueSlot::IsDestructed,
939 AggValueSlot::DoesNotNeedGCBarriers,
940 AggValueSlot::IsNotAliased,
941 AggValueSlot::DoesNotOverlap);
942 EmitAggExpr(copyExpr, Slot);
944 EmitSynthesizedCXXCopyCtor(blockField, src, copyExpr);
947 // If it's a reference variable, copy the reference into the block field.
948 } else if (type->isReferenceType()) {
949 Builder.CreateStore(src.getPointer(), blockField);
951 // If type is const-qualified, copy the value into the block field.
952 } else if (type.isConstQualified() &&
953 type.getObjCLifetime() == Qualifiers::OCL_Strong &&
954 CGM.getCodeGenOpts().OptimizationLevel != 0) {
955 llvm::Value *value = Builder.CreateLoad(src, "captured");
956 Builder.CreateStore(value, blockField);
958 // If this is an ARC __strong block-pointer variable, don't do a
961 // TODO: this can be generalized into the normal initialization logic:
962 // we should never need to do a block-copy when initializing a local
963 // variable, because the local variable's lifetime should be strictly
964 // contained within the stack block's.
965 } else if (type.getObjCLifetime() == Qualifiers::OCL_Strong &&
966 type->isBlockPointerType()) {
967 // Load the block and do a simple retain.
968 llvm::Value *value = Builder.CreateLoad(src, "block.captured_block");
969 value = EmitARCRetainNonBlock(value);
971 // Do a primitive store to the block field.
972 Builder.CreateStore(value, blockField);
974 // Otherwise, fake up a POD copy into the block field.
976 // Fake up a new variable so that EmitScalarInit doesn't think
977 // we're referring to the variable in its own initializer.
978 ImplicitParamDecl BlockFieldPseudoVar(getContext(), type,
979 ImplicitParamDecl::Other);
981 // We use one of these or the other depending on whether the
982 // reference is nested.
983 DeclRefExpr declRef(const_cast<VarDecl *>(variable),
984 /*RefersToEnclosingVariableOrCapture*/ CI.isNested(),
985 type, VK_LValue, SourceLocation());
987 ImplicitCastExpr l2r(ImplicitCastExpr::OnStack, type, CK_LValueToRValue,
988 &declRef, VK_RValue);
989 // FIXME: Pass a specific location for the expr init so that the store is
990 // attributed to a reasonable location - otherwise it may be attributed to
991 // locations of subexpressions in the initialization.
992 EmitExprAsInit(&l2r, &BlockFieldPseudoVar,
993 MakeAddrLValue(blockField, type, AlignmentSource::Decl),
994 /*captured by init*/ false);
997 // Activate the cleanup if layout pushed one.
999 EHScopeStack::stable_iterator cleanup = capture.getCleanup();
1000 if (cleanup.isValid())
1001 ActivateCleanupBlock(cleanup, blockInfo.DominatingIP);
1005 // Cast to the converted block-pointer type, which happens (somewhat
1006 // unfortunately) to be a pointer to function type.
1007 llvm::Value *result = Builder.CreatePointerCast(
1008 blockAddr.getPointer(), ConvertType(blockInfo.getBlockExpr()->getType()));
1011 CGM.getOpenCLRuntime().recordBlockInfo(blockInfo.BlockExpression, InvokeFn,
1019 llvm::Type *CodeGenModule::getBlockDescriptorType() {
1020 if (BlockDescriptorType)
1021 return BlockDescriptorType;
1023 llvm::Type *UnsignedLongTy =
1024 getTypes().ConvertType(getContext().UnsignedLongTy);
1026 // struct __block_descriptor {
1027 // unsigned long reserved;
1028 // unsigned long block_size;
1030 // // later, the following will be added
1033 // void (*copyHelper)();
1034 // void (*copyHelper)();
1035 // } helpers; // !!! optional
1037 // const char *signature; // the block signature
1038 // const char *layout; // reserved
1040 BlockDescriptorType = llvm::StructType::create(
1041 "struct.__block_descriptor", UnsignedLongTy, UnsignedLongTy);
1043 // Now form a pointer to that.
1044 unsigned AddrSpace = 0;
1045 if (getLangOpts().OpenCL)
1046 AddrSpace = getContext().getTargetAddressSpace(LangAS::opencl_constant);
1047 BlockDescriptorType = llvm::PointerType::get(BlockDescriptorType, AddrSpace);
1048 return BlockDescriptorType;
1051 llvm::Type *CodeGenModule::getGenericBlockLiteralType() {
1052 assert(!getLangOpts().OpenCL && "OpenCL does not need this");
1054 if (GenericBlockLiteralType)
1055 return GenericBlockLiteralType;
1057 llvm::Type *BlockDescPtrTy = getBlockDescriptorType();
1059 // struct __block_literal_generic {
1063 // void (*__invoke)(void *);
1064 // struct __block_descriptor *__descriptor;
1066 GenericBlockLiteralType =
1067 llvm::StructType::create("struct.__block_literal_generic", VoidPtrTy,
1068 IntTy, IntTy, VoidPtrTy, BlockDescPtrTy);
1070 return GenericBlockLiteralType;
1073 RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr *E,
1074 ReturnValueSlot ReturnValue) {
1075 const BlockPointerType *BPT =
1076 E->getCallee()->getType()->getAs<BlockPointerType>();
1078 llvm::Value *BlockPtr = EmitScalarExpr(E->getCallee());
1079 llvm::Value *FuncPtr;
1081 if (!CGM.getLangOpts().OpenCL) {
1082 // Get a pointer to the generic block literal.
1083 llvm::Type *BlockLiteralTy =
1084 llvm::PointerType::get(CGM.getGenericBlockLiteralType(), 0);
1086 // Bitcast the callee to a block literal.
1088 Builder.CreatePointerCast(BlockPtr, BlockLiteralTy, "block.literal");
1090 // Get the function pointer from the literal.
1092 Builder.CreateStructGEP(CGM.getGenericBlockLiteralType(), BlockPtr, 3);
1095 // Add the block literal.
1098 QualType VoidPtrQualTy = getContext().VoidPtrTy;
1099 llvm::Type *GenericVoidPtrTy = VoidPtrTy;
1100 if (getLangOpts().OpenCL) {
1101 GenericVoidPtrTy = CGM.getOpenCLRuntime().getGenericVoidPointerType();
1103 getContext().getPointerType(getContext().getAddrSpaceQualType(
1104 getContext().VoidTy, LangAS::opencl_generic));
1107 BlockPtr = Builder.CreatePointerCast(BlockPtr, GenericVoidPtrTy);
1108 Args.add(RValue::get(BlockPtr), VoidPtrQualTy);
1110 QualType FnType = BPT->getPointeeType();
1112 // And the rest of the arguments.
1113 EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(), E->arguments());
1115 // Load the function.
1117 if (CGM.getLangOpts().OpenCL)
1118 Func = CGM.getOpenCLRuntime().getInvokeFunction(E->getCallee());
1120 Func = Builder.CreateAlignedLoad(FuncPtr, getPointerAlign());
1122 const FunctionType *FuncTy = FnType->castAs<FunctionType>();
1123 const CGFunctionInfo &FnInfo =
1124 CGM.getTypes().arrangeBlockFunctionCall(Args, FuncTy);
1126 // Cast the function pointer to the right type.
1127 llvm::Type *BlockFTy = CGM.getTypes().GetFunctionType(FnInfo);
1129 llvm::Type *BlockFTyPtr = llvm::PointerType::getUnqual(BlockFTy);
1130 Func = Builder.CreatePointerCast(Func, BlockFTyPtr);
1132 // Prepare the callee.
1133 CGCallee Callee(CGCalleeInfo(), Func);
1135 // And call the block.
1136 return EmitCall(FnInfo, Callee, ReturnValue, Args);
1139 Address CodeGenFunction::GetAddrOfBlockDecl(const VarDecl *variable,
1141 assert(BlockInfo && "evaluating block ref without block information?");
1142 const CGBlockInfo::Capture &capture = BlockInfo->getCapture(variable);
1144 // Handle constant captures.
1145 if (capture.isConstant()) return LocalDeclMap.find(variable)->second;
1148 Builder.CreateStructGEP(LoadBlockStruct(), capture.getIndex(),
1149 capture.getOffset(), "block.capture.addr");
1152 // addr should be a void** right now. Load, then cast the result
1155 auto &byrefInfo = getBlockByrefInfo(variable);
1156 addr = Address(Builder.CreateLoad(addr), byrefInfo.ByrefAlignment);
1158 auto byrefPointerType = llvm::PointerType::get(byrefInfo.Type, 0);
1159 addr = Builder.CreateBitCast(addr, byrefPointerType, "byref.addr");
1161 addr = emitBlockByrefAddress(addr, byrefInfo, /*follow*/ true,
1162 variable->getName());
1165 if (capture.fieldType()->isReferenceType())
1166 addr = EmitLoadOfReference(MakeAddrLValue(addr, capture.fieldType()));
1171 void CodeGenModule::setAddrOfGlobalBlock(const BlockExpr *BE,
1172 llvm::Constant *Addr) {
1173 bool Ok = EmittedGlobalBlocks.insert(std::make_pair(BE, Addr)).second;
1175 assert(Ok && "Trying to replace an already-existing global block!");
1179 CodeGenModule::GetAddrOfGlobalBlock(const BlockExpr *BE,
1181 if (llvm::Constant *Block = getAddrOfGlobalBlockIfEmitted(BE))
1184 CGBlockInfo blockInfo(BE->getBlockDecl(), Name);
1185 blockInfo.BlockExpression = BE;
1187 // Compute information about the layout, etc., of this block.
1188 computeBlockInfo(*this, nullptr, blockInfo);
1190 // Using that metadata, generate the actual block function.
1192 CodeGenFunction::DeclMapTy LocalDeclMap;
1193 CodeGenFunction(*this).GenerateBlockFunction(
1194 GlobalDecl(), blockInfo, LocalDeclMap,
1195 /*IsLambdaConversionToBlock*/ false, /*BuildGlobalBlock*/ true);
1198 return getAddrOfGlobalBlockIfEmitted(BE);
1201 static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
1202 const CGBlockInfo &blockInfo,
1203 llvm::Constant *blockFn) {
1204 assert(blockInfo.CanBeGlobal);
1205 // Callers should detect this case on their own: calling this function
1206 // generally requires computing layout information, which is a waste of time
1207 // if we've already emitted this block.
1208 assert(!CGM.getAddrOfGlobalBlockIfEmitted(blockInfo.BlockExpression) &&
1209 "Refusing to re-emit a global block.");
1211 // Generate the constants for the block literal initializer.
1212 ConstantInitBuilder builder(CGM);
1213 auto fields = builder.beginStruct();
1215 bool IsOpenCL = CGM.getLangOpts().OpenCL;
1216 bool IsWindows = CGM.getTarget().getTriple().isOSWindows();
1220 fields.addNullPointer(CGM.Int8PtrPtrTy);
1222 fields.add(CGM.getNSConcreteGlobalBlock());
1225 BlockFlags flags = BLOCK_IS_GLOBAL | BLOCK_HAS_SIGNATURE;
1226 if (blockInfo.UsesStret)
1227 flags |= BLOCK_USE_STRET;
1229 fields.addInt(CGM.IntTy, flags.getBitMask());
1232 fields.addInt(CGM.IntTy, 0);
1235 fields.add(blockFn);
1237 fields.addInt(CGM.IntTy, blockInfo.BlockSize.getQuantity());
1238 fields.addInt(CGM.IntTy, blockInfo.BlockAlign.getQuantity());
1243 fields.add(buildBlockDescriptor(CGM, blockInfo));
1244 } else if (auto *Helper =
1245 CGM.getTargetCodeGenInfo().getTargetOpenCLBlockHelper()) {
1246 for (auto I : Helper->getCustomFieldValues(CGM, blockInfo)) {
1251 unsigned AddrSpace = 0;
1252 if (CGM.getContext().getLangOpts().OpenCL)
1253 AddrSpace = CGM.getContext().getTargetAddressSpace(LangAS::opencl_global);
1255 llvm::Constant *literal = fields.finishAndCreateGlobal(
1256 "__block_literal_global", blockInfo.BlockAlign,
1257 /*constant*/ !IsWindows, llvm::GlobalVariable::InternalLinkage, AddrSpace);
1259 // Windows does not allow globals to be initialised to point to globals in
1260 // different DLLs. Any such variables must run code to initialise them.
1262 auto *Init = llvm::Function::Create(llvm::FunctionType::get(CGM.VoidTy,
1263 {}), llvm::GlobalValue::InternalLinkage, ".block_isa_init",
1265 llvm::IRBuilder<> b(llvm::BasicBlock::Create(CGM.getLLVMContext(), "entry",
1267 b.CreateAlignedStore(CGM.getNSConcreteGlobalBlock(),
1268 b.CreateStructGEP(literal, 0), CGM.getPointerAlign().getQuantity());
1270 // We can't use the normal LLVM global initialisation array, because we
1271 // need to specify that this runs early in library initialisation.
1272 auto *InitVar = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
1273 /*isConstant*/true, llvm::GlobalValue::InternalLinkage,
1274 Init, ".block_isa_init_ptr");
1275 InitVar->setSection(".CRT$XCLa");
1276 CGM.addUsedGlobal(InitVar);
1279 // Return a constant of the appropriately-casted type.
1280 llvm::Type *RequiredType =
1281 CGM.getTypes().ConvertType(blockInfo.getBlockExpr()->getType());
1282 llvm::Constant *Result =
1283 llvm::ConstantExpr::getPointerCast(literal, RequiredType);
1284 CGM.setAddrOfGlobalBlock(blockInfo.BlockExpression, Result);
1285 if (CGM.getContext().getLangOpts().OpenCL)
1286 CGM.getOpenCLRuntime().recordBlockInfo(
1287 blockInfo.BlockExpression,
1288 cast<llvm::Function>(blockFn->stripPointerCasts()), Result);
1292 void CodeGenFunction::setBlockContextParameter(const ImplicitParamDecl *D,
1295 assert(BlockInfo && "not emitting prologue of block invocation function?!");
1297 // Allocate a stack slot like for any local variable to guarantee optimal
1298 // debug info at -O0. The mem2reg pass will eliminate it when optimizing.
1299 Address alloc = CreateMemTemp(D->getType(), D->getName() + ".addr");
1300 Builder.CreateStore(arg, alloc);
1301 if (CGDebugInfo *DI = getDebugInfo()) {
1302 if (CGM.getCodeGenOpts().getDebugInfo() >=
1303 codegenoptions::LimitedDebugInfo) {
1304 DI->setLocation(D->getLocation());
1305 DI->EmitDeclareOfBlockLiteralArgVariable(
1306 *BlockInfo, D->getName(), argNum,
1307 cast<llvm::AllocaInst>(alloc.getPointer()), Builder);
1311 SourceLocation StartLoc = BlockInfo->getBlockExpr()->getBody()->getLocStart();
1312 ApplyDebugLocation Scope(*this, StartLoc);
1314 // Instead of messing around with LocalDeclMap, just set the value
1315 // directly as BlockPointer.
1316 BlockPointer = Builder.CreatePointerCast(
1318 BlockInfo->StructureType->getPointerTo(
1319 getContext().getLangOpts().OpenCL
1320 ? getContext().getTargetAddressSpace(LangAS::opencl_generic)
1325 Address CodeGenFunction::LoadBlockStruct() {
1326 assert(BlockInfo && "not in a block invocation function!");
1327 assert(BlockPointer && "no block pointer set!");
1328 return Address(BlockPointer, BlockInfo->BlockAlign);
1332 CodeGenFunction::GenerateBlockFunction(GlobalDecl GD,
1333 const CGBlockInfo &blockInfo,
1334 const DeclMapTy &ldm,
1335 bool IsLambdaConversionToBlock,
1336 bool BuildGlobalBlock) {
1337 const BlockDecl *blockDecl = blockInfo.getBlockDecl();
1341 CurEHLocation = blockInfo.getBlockExpr()->getLocEnd();
1343 BlockInfo = &blockInfo;
1345 // Arrange for local static and local extern declarations to appear
1346 // to be local to this function as well, in case they're directly
1347 // referenced in a block.
1348 for (DeclMapTy::const_iterator i = ldm.begin(), e = ldm.end(); i != e; ++i) {
1349 const auto *var = dyn_cast<VarDecl>(i->first);
1350 if (var && !var->hasLocalStorage())
1351 setAddrOfLocalVar(var, i->second);
1354 // Begin building the function declaration.
1356 // Build the argument list.
1357 FunctionArgList args;
1359 // The first argument is the block pointer. Just take it as a void*
1360 // and cast it later.
1361 QualType selfTy = getContext().VoidPtrTy;
1363 // For OpenCL passed block pointer can be private AS local variable or
1364 // global AS program scope variable (for the case with and without captures).
1365 // Generic AS is used therefore to be able to accommodate both private and
1366 // generic AS in one implementation.
1367 if (getLangOpts().OpenCL)
1368 selfTy = getContext().getPointerType(getContext().getAddrSpaceQualType(
1369 getContext().VoidTy, LangAS::opencl_generic));
1371 IdentifierInfo *II = &CGM.getContext().Idents.get(".block_descriptor");
1373 ImplicitParamDecl SelfDecl(getContext(), const_cast<BlockDecl *>(blockDecl),
1374 SourceLocation(), II, selfTy,
1375 ImplicitParamDecl::ObjCSelf);
1376 args.push_back(&SelfDecl);
1378 // Now add the rest of the parameters.
1379 args.append(blockDecl->param_begin(), blockDecl->param_end());
1381 // Create the function declaration.
1382 const FunctionProtoType *fnType = blockInfo.getBlockExpr()->getFunctionType();
1383 const CGFunctionInfo &fnInfo =
1384 CGM.getTypes().arrangeBlockFunctionDeclaration(fnType, args);
1385 if (CGM.ReturnSlotInterferesWithArgs(fnInfo))
1386 blockInfo.UsesStret = true;
1388 llvm::FunctionType *fnLLVMType = CGM.getTypes().GetFunctionType(fnInfo);
1390 StringRef name = CGM.getBlockMangledName(GD, blockDecl);
1391 llvm::Function *fn = llvm::Function::Create(
1392 fnLLVMType, llvm::GlobalValue::InternalLinkage, name, &CGM.getModule());
1393 CGM.SetInternalFunctionAttributes(blockDecl, fn, fnInfo);
1395 if (BuildGlobalBlock) {
1396 auto GenVoidPtrTy = getContext().getLangOpts().OpenCL
1397 ? CGM.getOpenCLRuntime().getGenericVoidPointerType()
1399 buildGlobalBlock(CGM, blockInfo,
1400 llvm::ConstantExpr::getPointerCast(fn, GenVoidPtrTy));
1403 // Begin generating the function.
1404 StartFunction(blockDecl, fnType->getReturnType(), fn, fnInfo, args,
1405 blockDecl->getLocation(),
1406 blockInfo.getBlockExpr()->getBody()->getLocStart());
1408 // Okay. Undo some of what StartFunction did.
1410 // At -O0 we generate an explicit alloca for the BlockPointer, so the RA
1411 // won't delete the dbg.declare intrinsics for captured variables.
1412 llvm::Value *BlockPointerDbgLoc = BlockPointer;
1413 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1414 // Allocate a stack slot for it, so we can point the debugger to it
1415 Address Alloca = CreateTempAlloca(BlockPointer->getType(),
1418 // Set the DebugLocation to empty, so the store is recognized as a
1419 // frame setup instruction by llvm::DwarfDebug::beginFunction().
1420 auto NL = ApplyDebugLocation::CreateEmpty(*this);
1421 Builder.CreateStore(BlockPointer, Alloca);
1422 BlockPointerDbgLoc = Alloca.getPointer();
1425 // If we have a C++ 'this' reference, go ahead and force it into
1427 if (blockDecl->capturesCXXThis()) {
1429 Builder.CreateStructGEP(LoadBlockStruct(), blockInfo.CXXThisIndex,
1430 blockInfo.CXXThisOffset, "block.captured-this");
1431 CXXThisValue = Builder.CreateLoad(addr, "this");
1434 // Also force all the constant captures.
1435 for (const auto &CI : blockDecl->captures()) {
1436 const VarDecl *variable = CI.getVariable();
1437 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
1438 if (!capture.isConstant()) continue;
1440 CharUnits align = getContext().getDeclAlign(variable);
1442 CreateMemTemp(variable->getType(), align, "block.captured-const");
1444 Builder.CreateStore(capture.getConstant(), alloca);
1446 setAddrOfLocalVar(variable, alloca);
1449 // Save a spot to insert the debug information for all the DeclRefExprs.
1450 llvm::BasicBlock *entry = Builder.GetInsertBlock();
1451 llvm::BasicBlock::iterator entry_ptr = Builder.GetInsertPoint();
1454 if (IsLambdaConversionToBlock)
1455 EmitLambdaBlockInvokeBody();
1457 PGO.assignRegionCounters(GlobalDecl(blockDecl), fn);
1458 incrementProfileCounter(blockDecl->getBody());
1459 EmitStmt(blockDecl->getBody());
1462 // Remember where we were...
1463 llvm::BasicBlock *resume = Builder.GetInsertBlock();
1465 // Go back to the entry.
1467 Builder.SetInsertPoint(entry, entry_ptr);
1469 // Emit debug information for all the DeclRefExprs.
1470 // FIXME: also for 'this'
1471 if (CGDebugInfo *DI = getDebugInfo()) {
1472 for (const auto &CI : blockDecl->captures()) {
1473 const VarDecl *variable = CI.getVariable();
1474 DI->EmitLocation(Builder, variable->getLocation());
1476 if (CGM.getCodeGenOpts().getDebugInfo() >=
1477 codegenoptions::LimitedDebugInfo) {
1478 const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
1479 if (capture.isConstant()) {
1480 auto addr = LocalDeclMap.find(variable)->second;
1481 (void)DI->EmitDeclareOfAutoVariable(variable, addr.getPointer(),
1486 DI->EmitDeclareOfBlockDeclRefVariable(
1487 variable, BlockPointerDbgLoc, Builder, blockInfo,
1488 entry_ptr == entry->end() ? nullptr : &*entry_ptr);
1491 // Recover location if it was changed in the above loop.
1492 DI->EmitLocation(Builder,
1493 cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc());
1496 // And resume where we left off.
1497 if (resume == nullptr)
1498 Builder.ClearInsertionPoint();
1500 Builder.SetInsertPoint(resume);
1502 FinishFunction(cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc());
1509 /// Represents a type of copy/destroy operation that should be performed for an
1510 /// entity that's captured by a block.
1511 enum class BlockCaptureEntityKind {
1512 CXXRecord, // Copy or destroy
1516 BlockObject, // Assign or release
1520 /// Represents a captured entity that requires extra operations in order for
1521 /// this entity to be copied or destroyed correctly.
1522 struct BlockCaptureManagedEntity {
1523 BlockCaptureEntityKind Kind;
1524 BlockFieldFlags Flags;
1525 const BlockDecl::Capture &CI;
1526 const CGBlockInfo::Capture &Capture;
1528 BlockCaptureManagedEntity(BlockCaptureEntityKind Type, BlockFieldFlags Flags,
1529 const BlockDecl::Capture &CI,
1530 const CGBlockInfo::Capture &Capture)
1531 : Kind(Type), Flags(Flags), CI(CI), Capture(Capture) {}
1534 } // end anonymous namespace
1536 static std::pair<BlockCaptureEntityKind, BlockFieldFlags>
1537 computeCopyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T,
1538 const LangOptions &LangOpts) {
1539 if (CI.getCopyExpr()) {
1540 assert(!CI.isByRef());
1541 // don't bother computing flags
1542 return std::make_pair(BlockCaptureEntityKind::CXXRecord, BlockFieldFlags());
1544 BlockFieldFlags Flags;
1546 Flags = BLOCK_FIELD_IS_BYREF;
1547 if (T.isObjCGCWeak())
1548 Flags |= BLOCK_FIELD_IS_WEAK;
1549 return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags);
1552 Flags = BLOCK_FIELD_IS_OBJECT;
1553 bool isBlockPointer = T->isBlockPointerType();
1555 Flags = BLOCK_FIELD_IS_BLOCK;
1557 switch (T.isNonTrivialToPrimitiveCopy()) {
1558 case QualType::PCK_Struct:
1559 return std::make_pair(BlockCaptureEntityKind::NonTrivialCStruct,
1561 case QualType::PCK_ARCWeak:
1562 // We need to register __weak direct captures with the runtime.
1563 return std::make_pair(BlockCaptureEntityKind::ARCWeak, Flags);
1564 case QualType::PCK_ARCStrong:
1565 // We need to retain the copied value for __strong direct captures.
1566 // If it's a block pointer, we have to copy the block and assign that to
1567 // the destination pointer, so we might as well use _Block_object_assign.
1568 // Otherwise we can avoid that.
1569 return std::make_pair(!isBlockPointer ? BlockCaptureEntityKind::ARCStrong
1570 : BlockCaptureEntityKind::BlockObject,
1572 case QualType::PCK_Trivial:
1573 case QualType::PCK_VolatileTrivial: {
1574 if (!T->isObjCRetainableType())
1575 // For all other types, the memcpy is fine.
1576 return std::make_pair(BlockCaptureEntityKind::None, BlockFieldFlags());
1578 // Special rules for ARC captures:
1579 Qualifiers QS = T.getQualifiers();
1581 // Non-ARC captures of retainable pointers are strong and
1582 // therefore require a call to _Block_object_assign.
1583 if (!QS.getObjCLifetime() && !LangOpts.ObjCAutoRefCount)
1584 return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags);
1586 // Otherwise the memcpy is fine.
1587 return std::make_pair(BlockCaptureEntityKind::None, BlockFieldFlags());
1590 llvm_unreachable("after exhaustive PrimitiveCopyKind switch");
1593 /// Find the set of block captures that need to be explicitly copied or destroy.
1594 static void findBlockCapturedManagedEntities(
1595 const CGBlockInfo &BlockInfo, const LangOptions &LangOpts,
1596 SmallVectorImpl<BlockCaptureManagedEntity> &ManagedCaptures,
1597 llvm::function_ref<std::pair<BlockCaptureEntityKind, BlockFieldFlags>(
1598 const BlockDecl::Capture &, QualType, const LangOptions &)>
1600 for (const auto &CI : BlockInfo.getBlockDecl()->captures()) {
1601 const VarDecl *Variable = CI.getVariable();
1602 const CGBlockInfo::Capture &Capture = BlockInfo.getCapture(Variable);
1603 if (Capture.isConstant())
1606 auto Info = Predicate(CI, Variable->getType(), LangOpts);
1607 if (Info.first != BlockCaptureEntityKind::None)
1608 ManagedCaptures.emplace_back(Info.first, Info.second, CI, Capture);
1613 /// Release a __block variable.
1614 struct CallBlockRelease final : EHScopeStack::Cleanup {
1616 BlockFieldFlags FieldFlags;
1617 bool LoadBlockVarAddr;
1619 CallBlockRelease(Address Addr, BlockFieldFlags Flags, bool LoadValue)
1620 : Addr(Addr), FieldFlags(Flags), LoadBlockVarAddr(LoadValue) {}
1622 void Emit(CodeGenFunction &CGF, Flags flags) override {
1623 llvm::Value *BlockVarAddr;
1624 if (LoadBlockVarAddr) {
1625 BlockVarAddr = CGF.Builder.CreateLoad(Addr);
1626 BlockVarAddr = CGF.Builder.CreateBitCast(BlockVarAddr, CGF.VoidPtrTy);
1628 BlockVarAddr = Addr.getPointer();
1631 CGF.BuildBlockRelease(BlockVarAddr, FieldFlags);
1634 } // end anonymous namespace
1636 static void pushCaptureCleanup(BlockCaptureEntityKind CaptureKind,
1637 Address Field, QualType CaptureType,
1638 BlockFieldFlags Flags, bool EHOnly,
1639 CodeGenFunction &CGF) {
1640 switch (CaptureKind) {
1641 case BlockCaptureEntityKind::CXXRecord:
1642 case BlockCaptureEntityKind::ARCWeak:
1643 case BlockCaptureEntityKind::NonTrivialCStruct:
1644 case BlockCaptureEntityKind::ARCStrong: {
1645 if (CaptureType.isDestructedType() &&
1646 (!EHOnly || CGF.needsEHCleanup(CaptureType.isDestructedType()))) {
1647 CodeGenFunction::Destroyer *Destroyer =
1648 CaptureKind == BlockCaptureEntityKind::ARCStrong
1649 ? CodeGenFunction::destroyARCStrongImprecise
1650 : CGF.getDestroyer(CaptureType.isDestructedType());
1653 : CGF.getCleanupKind(CaptureType.isDestructedType());
1654 CGF.pushDestroy(Kind, Field, CaptureType, Destroyer, Kind & EHCleanup);
1658 case BlockCaptureEntityKind::BlockObject: {
1659 if (!EHOnly || CGF.getLangOpts().Exceptions) {
1660 CleanupKind Kind = EHOnly ? EHCleanup : NormalAndEHCleanup;
1661 CGF.enterByrefCleanup(Kind, Field, Flags, /*LoadBlockVarAddr*/ true);
1665 case BlockCaptureEntityKind::None:
1666 llvm_unreachable("unexpected BlockCaptureEntityKind");
1670 /// Generate the copy-helper function for a block closure object:
1671 /// static void block_copy_helper(block_t *dst, block_t *src);
1672 /// The runtime will have previously initialized 'dst' by doing a
1673 /// bit-copy of 'src'.
1675 /// Note that this copies an entire block closure object to the heap;
1676 /// it should not be confused with a 'byref copy helper', which moves
1677 /// the contents of an individual __block variable to the heap.
1679 CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) {
1680 ASTContext &C = getContext();
1682 FunctionArgList args;
1683 ImplicitParamDecl DstDecl(getContext(), C.VoidPtrTy,
1684 ImplicitParamDecl::Other);
1685 args.push_back(&DstDecl);
1686 ImplicitParamDecl SrcDecl(getContext(), C.VoidPtrTy,
1687 ImplicitParamDecl::Other);
1688 args.push_back(&SrcDecl);
1690 const CGFunctionInfo &FI =
1691 CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, args);
1693 // FIXME: it would be nice if these were mergeable with things with
1694 // identical semantics.
1695 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
1697 llvm::Function *Fn =
1698 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
1699 "__copy_helper_block_", &CGM.getModule());
1702 = &CGM.getContext().Idents.get("__copy_helper_block_");
1704 FunctionDecl *FD = FunctionDecl::Create(C,
1705 C.getTranslationUnitDecl(),
1707 SourceLocation(), II, C.VoidTy,
1712 CGM.SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
1714 StartFunction(FD, C.VoidTy, Fn, FI, args);
1715 ApplyDebugLocation NL{*this, blockInfo.getBlockExpr()->getLocStart()};
1716 llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
1718 Address src = GetAddrOfLocalVar(&SrcDecl);
1719 src = Address(Builder.CreateLoad(src), blockInfo.BlockAlign);
1720 src = Builder.CreateBitCast(src, structPtrTy, "block.source");
1722 Address dst = GetAddrOfLocalVar(&DstDecl);
1723 dst = Address(Builder.CreateLoad(dst), blockInfo.BlockAlign);
1724 dst = Builder.CreateBitCast(dst, structPtrTy, "block.dest");
1726 SmallVector<BlockCaptureManagedEntity, 4> CopiedCaptures;
1727 findBlockCapturedManagedEntities(blockInfo, getLangOpts(), CopiedCaptures,
1728 computeCopyInfoForBlockCapture);
1730 for (const auto &CopiedCapture : CopiedCaptures) {
1731 const BlockDecl::Capture &CI = CopiedCapture.CI;
1732 const CGBlockInfo::Capture &capture = CopiedCapture.Capture;
1733 QualType captureType = CI.getVariable()->getType();
1734 BlockFieldFlags flags = CopiedCapture.Flags;
1736 unsigned index = capture.getIndex();
1737 Address srcField = Builder.CreateStructGEP(src, index, capture.getOffset());
1738 Address dstField = Builder.CreateStructGEP(dst, index, capture.getOffset());
1740 // If there's an explicit copy expression, we do that.
1741 if (CI.getCopyExpr()) {
1742 assert(CopiedCapture.Kind == BlockCaptureEntityKind::CXXRecord);
1743 EmitSynthesizedCXXCopyCtor(dstField, srcField, CI.getCopyExpr());
1744 } else if (CopiedCapture.Kind == BlockCaptureEntityKind::ARCWeak) {
1745 EmitARCCopyWeak(dstField, srcField);
1746 // If this is a C struct that requires non-trivial copy construction, emit a
1747 // call to its copy constructor.
1748 } else if (CopiedCapture.Kind ==
1749 BlockCaptureEntityKind::NonTrivialCStruct) {
1750 QualType varType = CI.getVariable()->getType();
1751 callCStructCopyConstructor(MakeAddrLValue(dstField, varType),
1752 MakeAddrLValue(srcField, varType));
1754 llvm::Value *srcValue = Builder.CreateLoad(srcField, "blockcopy.src");
1755 if (CopiedCapture.Kind == BlockCaptureEntityKind::ARCStrong) {
1756 // At -O0, store null into the destination field (so that the
1757 // storeStrong doesn't over-release) and then call storeStrong.
1758 // This is a workaround to not having an initStrong call.
1759 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1760 auto *ty = cast<llvm::PointerType>(srcValue->getType());
1761 llvm::Value *null = llvm::ConstantPointerNull::get(ty);
1762 Builder.CreateStore(null, dstField);
1763 EmitARCStoreStrongCall(dstField, srcValue, true);
1765 // With optimization enabled, take advantage of the fact that
1766 // the blocks runtime guarantees a memcpy of the block data, and
1767 // just emit a retain of the src field.
1769 EmitARCRetainNonBlock(srcValue);
1771 // Unless EH cleanup is required, we don't need this anymore, so kill
1772 // it. It's not quite worth the annoyance to avoid creating it in the
1774 if (!needsEHCleanup(captureType.isDestructedType()))
1775 cast<llvm::Instruction>(dstField.getPointer())->eraseFromParent();
1778 assert(CopiedCapture.Kind == BlockCaptureEntityKind::BlockObject);
1779 srcValue = Builder.CreateBitCast(srcValue, VoidPtrTy);
1780 llvm::Value *dstAddr =
1781 Builder.CreateBitCast(dstField.getPointer(), VoidPtrTy);
1782 llvm::Value *args[] = {
1783 dstAddr, srcValue, llvm::ConstantInt::get(Int32Ty, flags.getBitMask())
1786 const VarDecl *variable = CI.getVariable();
1787 bool copyCanThrow = false;
1788 if (CI.isByRef() && variable->getType()->getAsCXXRecordDecl()) {
1789 const Expr *copyExpr =
1790 CGM.getContext().getBlockVarCopyInits(variable);
1792 copyCanThrow = true; // FIXME: reuse the noexcept logic
1797 EmitRuntimeCallOrInvoke(CGM.getBlockObjectAssign(), args);
1799 EmitNounwindRuntimeCall(CGM.getBlockObjectAssign(), args);
1804 // Ensure that we destroy the copied object if an exception is thrown later
1805 // in the helper function.
1806 pushCaptureCleanup(CopiedCapture.Kind, dstField, captureType, flags, /*EHOnly*/ true,
1812 return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
1815 static BlockFieldFlags
1816 getBlockFieldFlagsForObjCObjectPointer(const BlockDecl::Capture &CI,
1818 BlockFieldFlags Flags = BLOCK_FIELD_IS_OBJECT;
1819 if (T->isBlockPointerType())
1820 Flags = BLOCK_FIELD_IS_BLOCK;
1824 static std::pair<BlockCaptureEntityKind, BlockFieldFlags>
1825 computeDestroyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T,
1826 const LangOptions &LangOpts) {
1828 BlockFieldFlags Flags = BLOCK_FIELD_IS_BYREF;
1829 if (T.isObjCGCWeak())
1830 Flags |= BLOCK_FIELD_IS_WEAK;
1831 return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags);
1834 switch (T.isDestructedType()) {
1835 case QualType::DK_cxx_destructor:
1836 return std::make_pair(BlockCaptureEntityKind::CXXRecord, BlockFieldFlags());
1837 case QualType::DK_objc_strong_lifetime:
1838 // Use objc_storeStrong for __strong direct captures; the
1839 // dynamic tools really like it when we do this.
1840 return std::make_pair(BlockCaptureEntityKind::ARCStrong,
1841 getBlockFieldFlagsForObjCObjectPointer(CI, T));
1842 case QualType::DK_objc_weak_lifetime:
1843 // Support __weak direct captures.
1844 return std::make_pair(BlockCaptureEntityKind::ARCWeak,
1845 getBlockFieldFlagsForObjCObjectPointer(CI, T));
1846 case QualType::DK_nontrivial_c_struct:
1847 return std::make_pair(BlockCaptureEntityKind::NonTrivialCStruct,
1849 case QualType::DK_none: {
1850 // Non-ARC captures are strong, and we need to use _Block_object_dispose.
1851 if (T->isObjCRetainableType() && !T.getQualifiers().hasObjCLifetime() &&
1852 !LangOpts.ObjCAutoRefCount)
1853 return std::make_pair(BlockCaptureEntityKind::BlockObject,
1854 getBlockFieldFlagsForObjCObjectPointer(CI, T));
1855 // Otherwise, we have nothing to do.
1856 return std::make_pair(BlockCaptureEntityKind::None, BlockFieldFlags());
1859 llvm_unreachable("after exhaustive DestructionKind switch");
1862 /// Generate the destroy-helper function for a block closure object:
1863 /// static void block_destroy_helper(block_t *theBlock);
1865 /// Note that this destroys a heap-allocated block closure object;
1866 /// it should not be confused with a 'byref destroy helper', which
1867 /// destroys the heap-allocated contents of an individual __block
1870 CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) {
1871 ASTContext &C = getContext();
1873 FunctionArgList args;
1874 ImplicitParamDecl SrcDecl(getContext(), C.VoidPtrTy,
1875 ImplicitParamDecl::Other);
1876 args.push_back(&SrcDecl);
1878 const CGFunctionInfo &FI =
1879 CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, args);
1881 // FIXME: We'd like to put these into a mergable by content, with
1882 // internal linkage.
1883 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
1885 llvm::Function *Fn =
1886 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
1887 "__destroy_helper_block_", &CGM.getModule());
1890 = &CGM.getContext().Idents.get("__destroy_helper_block_");
1892 FunctionDecl *FD = FunctionDecl::Create(C, C.getTranslationUnitDecl(),
1894 SourceLocation(), II, C.VoidTy,
1898 CGM.SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
1900 StartFunction(FD, C.VoidTy, Fn, FI, args);
1901 ApplyDebugLocation NL{*this, blockInfo.getBlockExpr()->getLocStart()};
1903 llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
1905 Address src = GetAddrOfLocalVar(&SrcDecl);
1906 src = Address(Builder.CreateLoad(src), blockInfo.BlockAlign);
1907 src = Builder.CreateBitCast(src, structPtrTy, "block");
1909 CodeGenFunction::RunCleanupsScope cleanups(*this);
1911 SmallVector<BlockCaptureManagedEntity, 4> DestroyedCaptures;
1912 findBlockCapturedManagedEntities(blockInfo, getLangOpts(), DestroyedCaptures,
1913 computeDestroyInfoForBlockCapture);
1915 for (const auto &DestroyedCapture : DestroyedCaptures) {
1916 const BlockDecl::Capture &CI = DestroyedCapture.CI;
1917 const CGBlockInfo::Capture &capture = DestroyedCapture.Capture;
1918 BlockFieldFlags flags = DestroyedCapture.Flags;
1921 Builder.CreateStructGEP(src, capture.getIndex(), capture.getOffset());
1923 pushCaptureCleanup(DestroyedCapture.Kind, srcField,
1924 CI.getVariable()->getType(), flags, /*EHOnly*/ false, *this);
1927 cleanups.ForceCleanup();
1931 return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
1936 /// Emits the copy/dispose helper functions for a __block object of id type.
1937 class ObjectByrefHelpers final : public BlockByrefHelpers {
1938 BlockFieldFlags Flags;
1941 ObjectByrefHelpers(CharUnits alignment, BlockFieldFlags flags)
1942 : BlockByrefHelpers(alignment), Flags(flags) {}
1944 void emitCopy(CodeGenFunction &CGF, Address destField,
1945 Address srcField) override {
1946 destField = CGF.Builder.CreateBitCast(destField, CGF.VoidPtrTy);
1948 srcField = CGF.Builder.CreateBitCast(srcField, CGF.VoidPtrPtrTy);
1949 llvm::Value *srcValue = CGF.Builder.CreateLoad(srcField);
1951 unsigned flags = (Flags | BLOCK_BYREF_CALLER).getBitMask();
1953 llvm::Value *flagsVal = llvm::ConstantInt::get(CGF.Int32Ty, flags);
1954 llvm::Value *fn = CGF.CGM.getBlockObjectAssign();
1956 llvm::Value *args[] = { destField.getPointer(), srcValue, flagsVal };
1957 CGF.EmitNounwindRuntimeCall(fn, args);
1960 void emitDispose(CodeGenFunction &CGF, Address field) override {
1961 field = CGF.Builder.CreateBitCast(field, CGF.Int8PtrTy->getPointerTo(0));
1962 llvm::Value *value = CGF.Builder.CreateLoad(field);
1964 CGF.BuildBlockRelease(value, Flags | BLOCK_BYREF_CALLER);
1967 void profileImpl(llvm::FoldingSetNodeID &id) const override {
1968 id.AddInteger(Flags.getBitMask());
1972 /// Emits the copy/dispose helpers for an ARC __block __weak variable.
1973 class ARCWeakByrefHelpers final : public BlockByrefHelpers {
1975 ARCWeakByrefHelpers(CharUnits alignment) : BlockByrefHelpers(alignment) {}
1977 void emitCopy(CodeGenFunction &CGF, Address destField,
1978 Address srcField) override {
1979 CGF.EmitARCMoveWeak(destField, srcField);
1982 void emitDispose(CodeGenFunction &CGF, Address field) override {
1983 CGF.EmitARCDestroyWeak(field);
1986 void profileImpl(llvm::FoldingSetNodeID &id) const override {
1987 // 0 is distinguishable from all pointers and byref flags
1992 /// Emits the copy/dispose helpers for an ARC __block __strong variable
1993 /// that's not of block-pointer type.
1994 class ARCStrongByrefHelpers final : public BlockByrefHelpers {
1996 ARCStrongByrefHelpers(CharUnits alignment) : BlockByrefHelpers(alignment) {}
1998 void emitCopy(CodeGenFunction &CGF, Address destField,
1999 Address srcField) override {
2000 // Do a "move" by copying the value and then zeroing out the old
2003 llvm::Value *value = CGF.Builder.CreateLoad(srcField);
2006 llvm::ConstantPointerNull::get(cast<llvm::PointerType>(value->getType()));
2008 if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0) {
2009 CGF.Builder.CreateStore(null, destField);
2010 CGF.EmitARCStoreStrongCall(destField, value, /*ignored*/ true);
2011 CGF.EmitARCStoreStrongCall(srcField, null, /*ignored*/ true);
2014 CGF.Builder.CreateStore(value, destField);
2015 CGF.Builder.CreateStore(null, srcField);
2018 void emitDispose(CodeGenFunction &CGF, Address field) override {
2019 CGF.EmitARCDestroyStrong(field, ARCImpreciseLifetime);
2022 void profileImpl(llvm::FoldingSetNodeID &id) const override {
2023 // 1 is distinguishable from all pointers and byref flags
2028 /// Emits the copy/dispose helpers for an ARC __block __strong
2029 /// variable that's of block-pointer type.
2030 class ARCStrongBlockByrefHelpers final : public BlockByrefHelpers {
2032 ARCStrongBlockByrefHelpers(CharUnits alignment)
2033 : BlockByrefHelpers(alignment) {}
2035 void emitCopy(CodeGenFunction &CGF, Address destField,
2036 Address srcField) override {
2037 // Do the copy with objc_retainBlock; that's all that
2038 // _Block_object_assign would do anyway, and we'd have to pass the
2039 // right arguments to make sure it doesn't get no-op'ed.
2040 llvm::Value *oldValue = CGF.Builder.CreateLoad(srcField);
2041 llvm::Value *copy = CGF.EmitARCRetainBlock(oldValue, /*mandatory*/ true);
2042 CGF.Builder.CreateStore(copy, destField);
2045 void emitDispose(CodeGenFunction &CGF, Address field) override {
2046 CGF.EmitARCDestroyStrong(field, ARCImpreciseLifetime);
2049 void profileImpl(llvm::FoldingSetNodeID &id) const override {
2050 // 2 is distinguishable from all pointers and byref flags
2055 /// Emits the copy/dispose helpers for a __block variable with a
2056 /// nontrivial copy constructor or destructor.
2057 class CXXByrefHelpers final : public BlockByrefHelpers {
2059 const Expr *CopyExpr;
2062 CXXByrefHelpers(CharUnits alignment, QualType type,
2063 const Expr *copyExpr)
2064 : BlockByrefHelpers(alignment), VarType(type), CopyExpr(copyExpr) {}
2066 bool needsCopy() const override { return CopyExpr != nullptr; }
2067 void emitCopy(CodeGenFunction &CGF, Address destField,
2068 Address srcField) override {
2069 if (!CopyExpr) return;
2070 CGF.EmitSynthesizedCXXCopyCtor(destField, srcField, CopyExpr);
2073 void emitDispose(CodeGenFunction &CGF, Address field) override {
2074 EHScopeStack::stable_iterator cleanupDepth = CGF.EHStack.stable_begin();
2075 CGF.PushDestructorCleanup(VarType, field);
2076 CGF.PopCleanupBlocks(cleanupDepth);
2079 void profileImpl(llvm::FoldingSetNodeID &id) const override {
2080 id.AddPointer(VarType.getCanonicalType().getAsOpaquePtr());
2084 /// Emits the copy/dispose helpers for a __block variable that is a non-trivial
2086 class NonTrivialCStructByrefHelpers final : public BlockByrefHelpers {
2090 NonTrivialCStructByrefHelpers(CharUnits alignment, QualType type)
2091 : BlockByrefHelpers(alignment), VarType(type) {}
2093 void emitCopy(CodeGenFunction &CGF, Address destField,
2094 Address srcField) override {
2095 CGF.callCStructMoveConstructor(CGF.MakeAddrLValue(destField, VarType),
2096 CGF.MakeAddrLValue(srcField, VarType));
2099 bool needsDispose() const override {
2100 return VarType.isDestructedType();
2103 void emitDispose(CodeGenFunction &CGF, Address field) override {
2104 EHScopeStack::stable_iterator cleanupDepth = CGF.EHStack.stable_begin();
2105 CGF.pushDestroy(VarType.isDestructedType(), field, VarType);
2106 CGF.PopCleanupBlocks(cleanupDepth);
2109 void profileImpl(llvm::FoldingSetNodeID &id) const override {
2110 id.AddPointer(VarType.getCanonicalType().getAsOpaquePtr());
2113 } // end anonymous namespace
2115 static llvm::Constant *
2116 generateByrefCopyHelper(CodeGenFunction &CGF, const BlockByrefInfo &byrefInfo,
2117 BlockByrefHelpers &generator) {
2118 ASTContext &Context = CGF.getContext();
2120 QualType R = Context.VoidTy;
2122 FunctionArgList args;
2123 ImplicitParamDecl Dst(CGF.getContext(), Context.VoidPtrTy,
2124 ImplicitParamDecl::Other);
2125 args.push_back(&Dst);
2127 ImplicitParamDecl Src(CGF.getContext(), Context.VoidPtrTy,
2128 ImplicitParamDecl::Other);
2129 args.push_back(&Src);
2131 const CGFunctionInfo &FI =
2132 CGF.CGM.getTypes().arrangeBuiltinFunctionDeclaration(R, args);
2134 llvm::FunctionType *LTy = CGF.CGM.getTypes().GetFunctionType(FI);
2136 // FIXME: We'd like to put these into a mergable by content, with
2137 // internal linkage.
2138 llvm::Function *Fn =
2139 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
2140 "__Block_byref_object_copy_", &CGF.CGM.getModule());
2143 = &Context.Idents.get("__Block_byref_object_copy_");
2145 FunctionDecl *FD = FunctionDecl::Create(Context,
2146 Context.getTranslationUnitDecl(),
2148 SourceLocation(), II, R, nullptr,
2152 CGF.CGM.SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
2154 CGF.StartFunction(FD, R, Fn, FI, args);
2156 if (generator.needsCopy()) {
2157 llvm::Type *byrefPtrType = byrefInfo.Type->getPointerTo(0);
2160 Address destField = CGF.GetAddrOfLocalVar(&Dst);
2161 destField = Address(CGF.Builder.CreateLoad(destField),
2162 byrefInfo.ByrefAlignment);
2163 destField = CGF.Builder.CreateBitCast(destField, byrefPtrType);
2164 destField = CGF.emitBlockByrefAddress(destField, byrefInfo, false,
2168 Address srcField = CGF.GetAddrOfLocalVar(&Src);
2169 srcField = Address(CGF.Builder.CreateLoad(srcField),
2170 byrefInfo.ByrefAlignment);
2171 srcField = CGF.Builder.CreateBitCast(srcField, byrefPtrType);
2172 srcField = CGF.emitBlockByrefAddress(srcField, byrefInfo, false,
2175 generator.emitCopy(CGF, destField, srcField);
2178 CGF.FinishFunction();
2180 return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy);
2183 /// Build the copy helper for a __block variable.
2184 static llvm::Constant *buildByrefCopyHelper(CodeGenModule &CGM,
2185 const BlockByrefInfo &byrefInfo,
2186 BlockByrefHelpers &generator) {
2187 CodeGenFunction CGF(CGM);
2188 return generateByrefCopyHelper(CGF, byrefInfo, generator);
2191 /// Generate code for a __block variable's dispose helper.
2192 static llvm::Constant *
2193 generateByrefDisposeHelper(CodeGenFunction &CGF,
2194 const BlockByrefInfo &byrefInfo,
2195 BlockByrefHelpers &generator) {
2196 ASTContext &Context = CGF.getContext();
2197 QualType R = Context.VoidTy;
2199 FunctionArgList args;
2200 ImplicitParamDecl Src(CGF.getContext(), Context.VoidPtrTy,
2201 ImplicitParamDecl::Other);
2202 args.push_back(&Src);
2204 const CGFunctionInfo &FI =
2205 CGF.CGM.getTypes().arrangeBuiltinFunctionDeclaration(R, args);
2207 llvm::FunctionType *LTy = CGF.CGM.getTypes().GetFunctionType(FI);
2209 // FIXME: We'd like to put these into a mergable by content, with
2210 // internal linkage.
2211 llvm::Function *Fn =
2212 llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
2213 "__Block_byref_object_dispose_",
2214 &CGF.CGM.getModule());
2217 = &Context.Idents.get("__Block_byref_object_dispose_");
2219 FunctionDecl *FD = FunctionDecl::Create(Context,
2220 Context.getTranslationUnitDecl(),
2222 SourceLocation(), II, R, nullptr,
2226 CGF.CGM.SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
2228 CGF.StartFunction(FD, R, Fn, FI, args);
2230 if (generator.needsDispose()) {
2231 Address addr = CGF.GetAddrOfLocalVar(&Src);
2232 addr = Address(CGF.Builder.CreateLoad(addr), byrefInfo.ByrefAlignment);
2233 auto byrefPtrType = byrefInfo.Type->getPointerTo(0);
2234 addr = CGF.Builder.CreateBitCast(addr, byrefPtrType);
2235 addr = CGF.emitBlockByrefAddress(addr, byrefInfo, false, "object");
2237 generator.emitDispose(CGF, addr);
2240 CGF.FinishFunction();
2242 return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy);
2245 /// Build the dispose helper for a __block variable.
2246 static llvm::Constant *buildByrefDisposeHelper(CodeGenModule &CGM,
2247 const BlockByrefInfo &byrefInfo,
2248 BlockByrefHelpers &generator) {
2249 CodeGenFunction CGF(CGM);
2250 return generateByrefDisposeHelper(CGF, byrefInfo, generator);
2253 /// Lazily build the copy and dispose helpers for a __block variable
2254 /// with the given information.
2256 static T *buildByrefHelpers(CodeGenModule &CGM, const BlockByrefInfo &byrefInfo,
2258 llvm::FoldingSetNodeID id;
2259 generator.Profile(id);
2262 BlockByrefHelpers *node
2263 = CGM.ByrefHelpersCache.FindNodeOrInsertPos(id, insertPos);
2264 if (node) return static_cast<T*>(node);
2266 generator.CopyHelper = buildByrefCopyHelper(CGM, byrefInfo, generator);
2267 generator.DisposeHelper = buildByrefDisposeHelper(CGM, byrefInfo, generator);
2269 T *copy = new (CGM.getContext()) T(std::forward<T>(generator));
2270 CGM.ByrefHelpersCache.InsertNode(copy, insertPos);
2274 /// Build the copy and dispose helpers for the given __block variable
2275 /// emission. Places the helpers in the global cache. Returns null
2276 /// if no helpers are required.
2278 CodeGenFunction::buildByrefHelpers(llvm::StructType &byrefType,
2279 const AutoVarEmission &emission) {
2280 const VarDecl &var = *emission.Variable;
2281 QualType type = var.getType();
2283 auto &byrefInfo = getBlockByrefInfo(&var);
2285 // The alignment we care about for the purposes of uniquing byref
2286 // helpers is the alignment of the actual byref value field.
2287 CharUnits valueAlignment =
2288 byrefInfo.ByrefAlignment.alignmentAtOffset(byrefInfo.FieldOffset);
2290 if (const CXXRecordDecl *record = type->getAsCXXRecordDecl()) {
2291 const Expr *copyExpr = CGM.getContext().getBlockVarCopyInits(&var);
2292 if (!copyExpr && record->hasTrivialDestructor()) return nullptr;
2294 return ::buildByrefHelpers(
2295 CGM, byrefInfo, CXXByrefHelpers(valueAlignment, type, copyExpr));
2298 // If type is a non-trivial C struct type that is non-trivial to
2299 // destructly move or destroy, build the copy and dispose helpers.
2300 if (type.isNonTrivialToPrimitiveDestructiveMove() == QualType::PCK_Struct ||
2301 type.isDestructedType() == QualType::DK_nontrivial_c_struct)
2302 return ::buildByrefHelpers(
2303 CGM, byrefInfo, NonTrivialCStructByrefHelpers(valueAlignment, type));
2305 // Otherwise, if we don't have a retainable type, there's nothing to do.
2306 // that the runtime does extra copies.
2307 if (!type->isObjCRetainableType()) return nullptr;
2309 Qualifiers qs = type.getQualifiers();
2311 // If we have lifetime, that dominates.
2312 if (Qualifiers::ObjCLifetime lifetime = qs.getObjCLifetime()) {
2314 case Qualifiers::OCL_None: llvm_unreachable("impossible");
2316 // These are just bits as far as the runtime is concerned.
2317 case Qualifiers::OCL_ExplicitNone:
2318 case Qualifiers::OCL_Autoreleasing:
2321 // Tell the runtime that this is ARC __weak, called by the
2323 case Qualifiers::OCL_Weak:
2324 return ::buildByrefHelpers(CGM, byrefInfo,
2325 ARCWeakByrefHelpers(valueAlignment));
2327 // ARC __strong __block variables need to be retained.
2328 case Qualifiers::OCL_Strong:
2329 // Block pointers need to be copied, and there's no direct
2330 // transfer possible.
2331 if (type->isBlockPointerType()) {
2332 return ::buildByrefHelpers(CGM, byrefInfo,
2333 ARCStrongBlockByrefHelpers(valueAlignment));
2335 // Otherwise, we transfer ownership of the retain from the stack
2338 return ::buildByrefHelpers(CGM, byrefInfo,
2339 ARCStrongByrefHelpers(valueAlignment));
2342 llvm_unreachable("fell out of lifetime switch!");
2345 BlockFieldFlags flags;
2346 if (type->isBlockPointerType()) {
2347 flags |= BLOCK_FIELD_IS_BLOCK;
2348 } else if (CGM.getContext().isObjCNSObjectType(type) ||
2349 type->isObjCObjectPointerType()) {
2350 flags |= BLOCK_FIELD_IS_OBJECT;
2355 if (type.isObjCGCWeak())
2356 flags |= BLOCK_FIELD_IS_WEAK;
2358 return ::buildByrefHelpers(CGM, byrefInfo,
2359 ObjectByrefHelpers(valueAlignment, flags));
2362 Address CodeGenFunction::emitBlockByrefAddress(Address baseAddr,
2364 bool followForward) {
2365 auto &info = getBlockByrefInfo(var);
2366 return emitBlockByrefAddress(baseAddr, info, followForward, var->getName());
2369 Address CodeGenFunction::emitBlockByrefAddress(Address baseAddr,
2370 const BlockByrefInfo &info,
2372 const llvm::Twine &name) {
2373 // Chase the forwarding address if requested.
2374 if (followForward) {
2375 Address forwardingAddr =
2376 Builder.CreateStructGEP(baseAddr, 1, getPointerSize(), "forwarding");
2377 baseAddr = Address(Builder.CreateLoad(forwardingAddr), info.ByrefAlignment);
2380 return Builder.CreateStructGEP(baseAddr, info.FieldIndex,
2381 info.FieldOffset, name);
2384 /// BuildByrefInfo - This routine changes a __block variable declared as T x
2389 /// void *__forwarding;
2390 /// int32_t __flags;
2392 /// void *__copy_helper; // only if needed
2393 /// void *__destroy_helper; // only if needed
2394 /// void *__byref_variable_layout;// only if needed
2395 /// char padding[X]; // only if needed
2399 const BlockByrefInfo &CodeGenFunction::getBlockByrefInfo(const VarDecl *D) {
2400 auto it = BlockByrefInfos.find(D);
2401 if (it != BlockByrefInfos.end())
2404 llvm::StructType *byrefType =
2405 llvm::StructType::create(getLLVMContext(),
2406 "struct.__block_byref_" + D->getNameAsString());
2408 QualType Ty = D->getType();
2411 SmallVector<llvm::Type *, 8> types;
2414 types.push_back(Int8PtrTy);
2415 size += getPointerSize();
2417 // void *__forwarding;
2418 types.push_back(llvm::PointerType::getUnqual(byrefType));
2419 size += getPointerSize();
2422 types.push_back(Int32Ty);
2423 size += CharUnits::fromQuantity(4);
2426 types.push_back(Int32Ty);
2427 size += CharUnits::fromQuantity(4);
2429 // Note that this must match *exactly* the logic in buildByrefHelpers.
2430 bool hasCopyAndDispose = getContext().BlockRequiresCopying(Ty, D);
2431 if (hasCopyAndDispose) {
2432 /// void *__copy_helper;
2433 types.push_back(Int8PtrTy);
2434 size += getPointerSize();
2436 /// void *__destroy_helper;
2437 types.push_back(Int8PtrTy);
2438 size += getPointerSize();
2441 bool HasByrefExtendedLayout = false;
2442 Qualifiers::ObjCLifetime Lifetime;
2443 if (getContext().getByrefLifetime(Ty, Lifetime, HasByrefExtendedLayout) &&
2444 HasByrefExtendedLayout) {
2445 /// void *__byref_variable_layout;
2446 types.push_back(Int8PtrTy);
2447 size += CharUnits::fromQuantity(PointerSizeInBytes);
2451 llvm::Type *varTy = ConvertTypeForMem(Ty);
2453 bool packed = false;
2454 CharUnits varAlign = getContext().getDeclAlign(D);
2455 CharUnits varOffset = size.alignTo(varAlign);
2457 // We may have to insert padding.
2458 if (varOffset != size) {
2459 llvm::Type *paddingTy =
2460 llvm::ArrayType::get(Int8Ty, (varOffset - size).getQuantity());
2462 types.push_back(paddingTy);
2465 // Conversely, we might have to prevent LLVM from inserting padding.
2466 } else if (CGM.getDataLayout().getABITypeAlignment(varTy)
2467 > varAlign.getQuantity()) {
2470 types.push_back(varTy);
2472 byrefType->setBody(types, packed);
2474 BlockByrefInfo info;
2475 info.Type = byrefType;
2476 info.FieldIndex = types.size() - 1;
2477 info.FieldOffset = varOffset;
2478 info.ByrefAlignment = std::max(varAlign, getPointerAlign());
2480 auto pair = BlockByrefInfos.insert({D, info});
2481 assert(pair.second && "info was inserted recursively?");
2482 return pair.first->second;
2485 /// Initialize the structural components of a __block variable, i.e.
2486 /// everything but the actual object.
2487 void CodeGenFunction::emitByrefStructureInit(const AutoVarEmission &emission) {
2488 // Find the address of the local.
2489 Address addr = emission.Addr;
2491 // That's an alloca of the byref structure type.
2492 llvm::StructType *byrefType = cast<llvm::StructType>(
2493 cast<llvm::PointerType>(addr.getPointer()->getType())->getElementType());
2495 unsigned nextHeaderIndex = 0;
2496 CharUnits nextHeaderOffset;
2497 auto storeHeaderField = [&](llvm::Value *value, CharUnits fieldSize,
2498 const Twine &name) {
2499 auto fieldAddr = Builder.CreateStructGEP(addr, nextHeaderIndex,
2500 nextHeaderOffset, name);
2501 Builder.CreateStore(value, fieldAddr);
2504 nextHeaderOffset += fieldSize;
2507 // Build the byref helpers if necessary. This is null if we don't need any.
2508 BlockByrefHelpers *helpers = buildByrefHelpers(*byrefType, emission);
2510 const VarDecl &D = *emission.Variable;
2511 QualType type = D.getType();
2513 bool HasByrefExtendedLayout;
2514 Qualifiers::ObjCLifetime ByrefLifetime;
2515 bool ByRefHasLifetime =
2516 getContext().getByrefLifetime(type, ByrefLifetime, HasByrefExtendedLayout);
2520 // Initialize the 'isa', which is just 0 or 1.
2522 if (type.isObjCGCWeak())
2524 V = Builder.CreateIntToPtr(Builder.getInt32(isa), Int8PtrTy, "isa");
2525 storeHeaderField(V, getPointerSize(), "byref.isa");
2527 // Store the address of the variable into its own forwarding pointer.
2528 storeHeaderField(addr.getPointer(), getPointerSize(), "byref.forwarding");
2531 // c) the flags field is set to either 0 if no helper functions are
2532 // needed or BLOCK_BYREF_HAS_COPY_DISPOSE if they are,
2534 if (helpers) flags |= BLOCK_BYREF_HAS_COPY_DISPOSE;
2535 if (ByRefHasLifetime) {
2536 if (HasByrefExtendedLayout) flags |= BLOCK_BYREF_LAYOUT_EXTENDED;
2537 else switch (ByrefLifetime) {
2538 case Qualifiers::OCL_Strong:
2539 flags |= BLOCK_BYREF_LAYOUT_STRONG;
2541 case Qualifiers::OCL_Weak:
2542 flags |= BLOCK_BYREF_LAYOUT_WEAK;
2544 case Qualifiers::OCL_ExplicitNone:
2545 flags |= BLOCK_BYREF_LAYOUT_UNRETAINED;
2547 case Qualifiers::OCL_None:
2548 if (!type->isObjCObjectPointerType() && !type->isBlockPointerType())
2549 flags |= BLOCK_BYREF_LAYOUT_NON_OBJECT;
2554 if (CGM.getLangOpts().ObjCGCBitmapPrint) {
2555 printf("\n Inline flag for BYREF variable layout (%d):", flags.getBitMask());
2556 if (flags & BLOCK_BYREF_HAS_COPY_DISPOSE)
2557 printf(" BLOCK_BYREF_HAS_COPY_DISPOSE");
2558 if (flags & BLOCK_BYREF_LAYOUT_MASK) {
2559 BlockFlags ThisFlag(flags.getBitMask() & BLOCK_BYREF_LAYOUT_MASK);
2560 if (ThisFlag == BLOCK_BYREF_LAYOUT_EXTENDED)
2561 printf(" BLOCK_BYREF_LAYOUT_EXTENDED");
2562 if (ThisFlag == BLOCK_BYREF_LAYOUT_STRONG)
2563 printf(" BLOCK_BYREF_LAYOUT_STRONG");
2564 if (ThisFlag == BLOCK_BYREF_LAYOUT_WEAK)
2565 printf(" BLOCK_BYREF_LAYOUT_WEAK");
2566 if (ThisFlag == BLOCK_BYREF_LAYOUT_UNRETAINED)
2567 printf(" BLOCK_BYREF_LAYOUT_UNRETAINED");
2568 if (ThisFlag == BLOCK_BYREF_LAYOUT_NON_OBJECT)
2569 printf(" BLOCK_BYREF_LAYOUT_NON_OBJECT");
2574 storeHeaderField(llvm::ConstantInt::get(IntTy, flags.getBitMask()),
2575 getIntSize(), "byref.flags");
2577 CharUnits byrefSize = CGM.GetTargetTypeStoreSize(byrefType);
2578 V = llvm::ConstantInt::get(IntTy, byrefSize.getQuantity());
2579 storeHeaderField(V, getIntSize(), "byref.size");
2582 storeHeaderField(helpers->CopyHelper, getPointerSize(),
2583 "byref.copyHelper");
2584 storeHeaderField(helpers->DisposeHelper, getPointerSize(),
2585 "byref.disposeHelper");
2588 if (ByRefHasLifetime && HasByrefExtendedLayout) {
2589 auto layoutInfo = CGM.getObjCRuntime().BuildByrefLayout(CGM, type);
2590 storeHeaderField(layoutInfo, getPointerSize(), "byref.layout");
2594 void CodeGenFunction::BuildBlockRelease(llvm::Value *V, BlockFieldFlags flags) {
2595 llvm::Value *F = CGM.getBlockObjectDispose();
2596 llvm::Value *args[] = {
2597 Builder.CreateBitCast(V, Int8PtrTy),
2598 llvm::ConstantInt::get(Int32Ty, flags.getBitMask())
2600 EmitNounwindRuntimeCall(F, args); // FIXME: throwing destructors?
2603 void CodeGenFunction::enterByrefCleanup(CleanupKind Kind, Address Addr,
2604 BlockFieldFlags Flags,
2605 bool LoadBlockVarAddr) {
2606 EHStack.pushCleanup<CallBlockRelease>(Kind, Addr, Flags, LoadBlockVarAddr);
2609 /// Adjust the declaration of something from the blocks API.
2610 static void configureBlocksRuntimeObject(CodeGenModule &CGM,
2611 llvm::Constant *C) {
2612 auto *GV = cast<llvm::GlobalValue>(C->stripPointerCasts());
2614 if (CGM.getTarget().getTriple().isOSBinFormatCOFF()) {
2615 IdentifierInfo &II = CGM.getContext().Idents.get(C->getName());
2616 TranslationUnitDecl *TUDecl = CGM.getContext().getTranslationUnitDecl();
2617 DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
2619 assert((isa<llvm::Function>(C->stripPointerCasts()) ||
2620 isa<llvm::GlobalVariable>(C->stripPointerCasts())) &&
2621 "expected Function or GlobalVariable");
2623 const NamedDecl *ND = nullptr;
2624 for (const auto &Result : DC->lookup(&II))
2625 if ((ND = dyn_cast<FunctionDecl>(Result)) ||
2626 (ND = dyn_cast<VarDecl>(Result)))
2629 // TODO: support static blocks runtime
2630 if (GV->isDeclaration() && (!ND || !ND->hasAttr<DLLExportAttr>())) {
2631 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
2632 GV->setLinkage(llvm::GlobalValue::ExternalLinkage);
2634 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
2635 GV->setLinkage(llvm::GlobalValue::ExternalLinkage);
2639 if (CGM.getLangOpts().BlocksRuntimeOptional && GV->isDeclaration() &&
2640 GV->hasExternalLinkage())
2641 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
2643 CGM.setDSOLocal(GV);
2646 llvm::Constant *CodeGenModule::getBlockObjectDispose() {
2647 if (BlockObjectDispose)
2648 return BlockObjectDispose;
2650 llvm::Type *args[] = { Int8PtrTy, Int32Ty };
2651 llvm::FunctionType *fty
2652 = llvm::FunctionType::get(VoidTy, args, false);
2653 BlockObjectDispose = CreateRuntimeFunction(fty, "_Block_object_dispose");
2654 configureBlocksRuntimeObject(*this, BlockObjectDispose);
2655 return BlockObjectDispose;
2658 llvm::Constant *CodeGenModule::getBlockObjectAssign() {
2659 if (BlockObjectAssign)
2660 return BlockObjectAssign;
2662 llvm::Type *args[] = { Int8PtrTy, Int8PtrTy, Int32Ty };
2663 llvm::FunctionType *fty
2664 = llvm::FunctionType::get(VoidTy, args, false);
2665 BlockObjectAssign = CreateRuntimeFunction(fty, "_Block_object_assign");
2666 configureBlocksRuntimeObject(*this, BlockObjectAssign);
2667 return BlockObjectAssign;
2670 llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() {
2671 if (NSConcreteGlobalBlock)
2672 return NSConcreteGlobalBlock;
2674 NSConcreteGlobalBlock = GetOrCreateLLVMGlobal("_NSConcreteGlobalBlock",
2675 Int8PtrTy->getPointerTo(),
2677 configureBlocksRuntimeObject(*this, NSConcreteGlobalBlock);
2678 return NSConcreteGlobalBlock;
2681 llvm::Constant *CodeGenModule::getNSConcreteStackBlock() {
2682 if (NSConcreteStackBlock)
2683 return NSConcreteStackBlock;
2685 NSConcreteStackBlock = GetOrCreateLLVMGlobal("_NSConcreteStackBlock",
2686 Int8PtrTy->getPointerTo(),
2688 configureBlocksRuntimeObject(*this, NSConcreteStackBlock);
2689 return NSConcreteStackBlock;