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Diffstat (limited to 'contrib/llvm/tools/clang/lib/CodeGen/CGBlocks.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/CodeGen/CGBlocks.cpp | 2500 |
1 files changed, 2500 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CGBlocks.cpp b/contrib/llvm/tools/clang/lib/CodeGen/CGBlocks.cpp new file mode 100644 index 000000000000..181048957879 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/CGBlocks.cpp @@ -0,0 +1,2500 @@ +//===--- CGBlocks.cpp - Emit LLVM Code for declarations ---------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This contains code to emit blocks. +// +//===----------------------------------------------------------------------===// + +#include "CGBlocks.h" +#include "CGDebugInfo.h" +#include "CGObjCRuntime.h" +#include "CodeGenFunction.h" +#include "CodeGenModule.h" +#include "clang/CodeGen/ConstantInitBuilder.h" +#include "clang/AST/DeclObjC.h" +#include "llvm/ADT/SmallSet.h" +#include "llvm/IR/CallSite.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/Module.h" +#include <algorithm> +#include <cstdio> + +using namespace clang; +using namespace CodeGen; + +CGBlockInfo::CGBlockInfo(const BlockDecl *block, StringRef name) + : Name(name), CXXThisIndex(0), CanBeGlobal(false), NeedsCopyDispose(false), + HasCXXObject(false), UsesStret(false), HasCapturedVariableLayout(false), + LocalAddress(Address::invalid()), StructureType(nullptr), Block(block), + DominatingIP(nullptr) { + + // Skip asm prefix, if any. 'name' is usually taken directly from + // the mangled name of the enclosing function. + if (!name.empty() && name[0] == '\01') + name = name.substr(1); +} + +// Anchor the vtable to this translation unit. +BlockByrefHelpers::~BlockByrefHelpers() {} + +/// Build the given block as a global block. +static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM, + const CGBlockInfo &blockInfo, + llvm::Constant *blockFn); + +/// Build the helper function to copy a block. +static llvm::Constant *buildCopyHelper(CodeGenModule &CGM, + const CGBlockInfo &blockInfo) { + return CodeGenFunction(CGM).GenerateCopyHelperFunction(blockInfo); +} + +/// Build the helper function to dispose of a block. +static llvm::Constant *buildDisposeHelper(CodeGenModule &CGM, + const CGBlockInfo &blockInfo) { + return CodeGenFunction(CGM).GenerateDestroyHelperFunction(blockInfo); +} + +/// buildBlockDescriptor - Build the block descriptor meta-data for a block. +/// buildBlockDescriptor is accessed from 5th field of the Block_literal +/// meta-data and contains stationary information about the block literal. +/// Its definition will have 4 (or optinally 6) words. +/// \code +/// struct Block_descriptor { +/// unsigned long reserved; +/// unsigned long size; // size of Block_literal metadata in bytes. +/// void *copy_func_helper_decl; // optional copy helper. +/// void *destroy_func_decl; // optioanl destructor helper. +/// void *block_method_encoding_address; // @encode for block literal signature. +/// void *block_layout_info; // encoding of captured block variables. +/// }; +/// \endcode +static llvm::Constant *buildBlockDescriptor(CodeGenModule &CGM, + const CGBlockInfo &blockInfo) { + ASTContext &C = CGM.getContext(); + + llvm::IntegerType *ulong = + cast<llvm::IntegerType>(CGM.getTypes().ConvertType(C.UnsignedLongTy)); + llvm::PointerType *i8p = nullptr; + if (CGM.getLangOpts().OpenCL) + i8p = + llvm::Type::getInt8PtrTy( + CGM.getLLVMContext(), C.getTargetAddressSpace(LangAS::opencl_constant)); + else + i8p = CGM.VoidPtrTy; + + ConstantInitBuilder builder(CGM); + auto elements = builder.beginStruct(); + + // reserved + elements.addInt(ulong, 0); + + // Size + // FIXME: What is the right way to say this doesn't fit? We should give + // a user diagnostic in that case. Better fix would be to change the + // API to size_t. + elements.addInt(ulong, blockInfo.BlockSize.getQuantity()); + + // Optional copy/dispose helpers. + if (blockInfo.NeedsCopyDispose) { + // copy_func_helper_decl + elements.add(buildCopyHelper(CGM, blockInfo)); + + // destroy_func_decl + elements.add(buildDisposeHelper(CGM, blockInfo)); + } + + // Signature. Mandatory ObjC-style method descriptor @encode sequence. + std::string typeAtEncoding = + CGM.getContext().getObjCEncodingForBlock(blockInfo.getBlockExpr()); + elements.add(llvm::ConstantExpr::getBitCast( + CGM.GetAddrOfConstantCString(typeAtEncoding).getPointer(), i8p)); + + // GC layout. + if (C.getLangOpts().ObjC1) { + if (CGM.getLangOpts().getGC() != LangOptions::NonGC) + elements.add(CGM.getObjCRuntime().BuildGCBlockLayout(CGM, blockInfo)); + else + elements.add(CGM.getObjCRuntime().BuildRCBlockLayout(CGM, blockInfo)); + } + else + elements.addNullPointer(i8p); + + unsigned AddrSpace = 0; + if (C.getLangOpts().OpenCL) + AddrSpace = C.getTargetAddressSpace(LangAS::opencl_constant); + + llvm::GlobalVariable *global = + elements.finishAndCreateGlobal("__block_descriptor_tmp", + CGM.getPointerAlign(), + /*constant*/ true, + llvm::GlobalValue::InternalLinkage, + AddrSpace); + + return llvm::ConstantExpr::getBitCast(global, CGM.getBlockDescriptorType()); +} + +/* + Purely notional variadic template describing the layout of a block. + + template <class _ResultType, class... _ParamTypes, class... _CaptureTypes> + struct Block_literal { + /// Initialized to one of: + /// extern void *_NSConcreteStackBlock[]; + /// extern void *_NSConcreteGlobalBlock[]; + /// + /// In theory, we could start one off malloc'ed by setting + /// BLOCK_NEEDS_FREE, giving it a refcount of 1, and using + /// this isa: + /// extern void *_NSConcreteMallocBlock[]; + struct objc_class *isa; + + /// These are the flags (with corresponding bit number) that the + /// compiler is actually supposed to know about. + /// 25. BLOCK_HAS_COPY_DISPOSE - indicates that the block + /// descriptor provides copy and dispose helper functions + /// 26. BLOCK_HAS_CXX_OBJ - indicates that there's a captured + /// object with a nontrivial destructor or copy constructor + /// 28. BLOCK_IS_GLOBAL - indicates that the block is allocated + /// as global memory + /// 29. BLOCK_USE_STRET - indicates that the block function + /// uses stret, which objc_msgSend needs to know about + /// 30. BLOCK_HAS_SIGNATURE - indicates that the block has an + /// @encoded signature string + /// And we're not supposed to manipulate these: + /// 24. BLOCK_NEEDS_FREE - indicates that the block has been moved + /// to malloc'ed memory + /// 27. BLOCK_IS_GC - indicates that the block has been moved to + /// to GC-allocated memory + /// Additionally, the bottom 16 bits are a reference count which + /// should be zero on the stack. + int flags; + + /// Reserved; should be zero-initialized. + int reserved; + + /// Function pointer generated from block literal. + _ResultType (*invoke)(Block_literal *, _ParamTypes...); + + /// Block description metadata generated from block literal. + struct Block_descriptor *block_descriptor; + + /// Captured values follow. + _CapturesTypes captures...; + }; + */ + +namespace { + /// A chunk of data that we actually have to capture in the block. + struct BlockLayoutChunk { + CharUnits Alignment; + CharUnits Size; + Qualifiers::ObjCLifetime Lifetime; + const BlockDecl::Capture *Capture; // null for 'this' + llvm::Type *Type; + QualType FieldType; + + BlockLayoutChunk(CharUnits align, CharUnits size, + Qualifiers::ObjCLifetime lifetime, + const BlockDecl::Capture *capture, + llvm::Type *type, QualType fieldType) + : Alignment(align), Size(size), Lifetime(lifetime), + Capture(capture), Type(type), FieldType(fieldType) {} + + /// Tell the block info that this chunk has the given field index. + void setIndex(CGBlockInfo &info, unsigned index, CharUnits offset) { + if (!Capture) { + info.CXXThisIndex = index; + info.CXXThisOffset = offset; + } else { + auto C = CGBlockInfo::Capture::makeIndex(index, offset, FieldType); + info.Captures.insert({Capture->getVariable(), C}); + } + } + }; + + /// Order by 1) all __strong together 2) next, all byfref together 3) next, + /// all __weak together. Preserve descending alignment in all situations. + bool operator<(const BlockLayoutChunk &left, const BlockLayoutChunk &right) { + if (left.Alignment != right.Alignment) + return left.Alignment > right.Alignment; + + auto getPrefOrder = [](const BlockLayoutChunk &chunk) { + if (chunk.Capture && chunk.Capture->isByRef()) + return 1; + if (chunk.Lifetime == Qualifiers::OCL_Strong) + return 0; + if (chunk.Lifetime == Qualifiers::OCL_Weak) + return 2; + return 3; + }; + + return getPrefOrder(left) < getPrefOrder(right); + } +} // end anonymous namespace + +/// Determines if the given type is safe for constant capture in C++. +static bool isSafeForCXXConstantCapture(QualType type) { + const RecordType *recordType = + type->getBaseElementTypeUnsafe()->getAs<RecordType>(); + + // Only records can be unsafe. + if (!recordType) return true; + + const auto *record = cast<CXXRecordDecl>(recordType->getDecl()); + + // Maintain semantics for classes with non-trivial dtors or copy ctors. + if (!record->hasTrivialDestructor()) return false; + if (record->hasNonTrivialCopyConstructor()) return false; + + // Otherwise, we just have to make sure there aren't any mutable + // fields that might have changed since initialization. + return !record->hasMutableFields(); +} + +/// It is illegal to modify a const object after initialization. +/// Therefore, if a const object has a constant initializer, we don't +/// actually need to keep storage for it in the block; we'll just +/// rematerialize it at the start of the block function. This is +/// acceptable because we make no promises about address stability of +/// captured variables. +static llvm::Constant *tryCaptureAsConstant(CodeGenModule &CGM, + CodeGenFunction *CGF, + const VarDecl *var) { + // Return if this is a function parameter. We shouldn't try to + // rematerialize default arguments of function parameters. + if (isa<ParmVarDecl>(var)) + return nullptr; + + QualType type = var->getType(); + + // We can only do this if the variable is const. + if (!type.isConstQualified()) return nullptr; + + // Furthermore, in C++ we have to worry about mutable fields: + // C++ [dcl.type.cv]p4: + // Except that any class member declared mutable can be + // modified, any attempt to modify a const object during its + // lifetime results in undefined behavior. + if (CGM.getLangOpts().CPlusPlus && !isSafeForCXXConstantCapture(type)) + return nullptr; + + // If the variable doesn't have any initializer (shouldn't this be + // invalid?), it's not clear what we should do. Maybe capture as + // zero? + const Expr *init = var->getInit(); + if (!init) return nullptr; + + return CGM.EmitConstantInit(*var, CGF); +} + +/// Get the low bit of a nonzero character count. This is the +/// alignment of the nth byte if the 0th byte is universally aligned. +static CharUnits getLowBit(CharUnits v) { + return CharUnits::fromQuantity(v.getQuantity() & (~v.getQuantity() + 1)); +} + +static void initializeForBlockHeader(CodeGenModule &CGM, CGBlockInfo &info, + SmallVectorImpl<llvm::Type*> &elementTypes) { + // The header is basically 'struct { void *; int; int; void *; void *; }'. + // Assert that that struct is packed. + assert(CGM.getIntSize() <= CGM.getPointerSize()); + assert(CGM.getIntAlign() <= CGM.getPointerAlign()); + assert((2 * CGM.getIntSize()).isMultipleOf(CGM.getPointerAlign())); + + info.BlockAlign = CGM.getPointerAlign(); + info.BlockSize = 3 * CGM.getPointerSize() + 2 * CGM.getIntSize(); + + assert(elementTypes.empty()); + elementTypes.push_back(CGM.VoidPtrTy); + elementTypes.push_back(CGM.IntTy); + elementTypes.push_back(CGM.IntTy); + elementTypes.push_back(CGM.VoidPtrTy); + elementTypes.push_back(CGM.getBlockDescriptorType()); +} + +static QualType getCaptureFieldType(const CodeGenFunction &CGF, + const BlockDecl::Capture &CI) { + const VarDecl *VD = CI.getVariable(); + + // If the variable is captured by an enclosing block or lambda expression, + // use the type of the capture field. + if (CGF.BlockInfo && CI.isNested()) + return CGF.BlockInfo->getCapture(VD).fieldType(); + if (auto *FD = CGF.LambdaCaptureFields.lookup(VD)) + return FD->getType(); + return VD->getType(); +} + +/// Compute the layout of the given block. Attempts to lay the block +/// out with minimal space requirements. +static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF, + CGBlockInfo &info) { + ASTContext &C = CGM.getContext(); + const BlockDecl *block = info.getBlockDecl(); + + SmallVector<llvm::Type*, 8> elementTypes; + initializeForBlockHeader(CGM, info, elementTypes); + + if (!block->hasCaptures()) { + info.StructureType = + llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); + info.CanBeGlobal = true; + return; + } + else if (C.getLangOpts().ObjC1 && + CGM.getLangOpts().getGC() == LangOptions::NonGC) + info.HasCapturedVariableLayout = true; + + // Collect the layout chunks. + SmallVector<BlockLayoutChunk, 16> layout; + layout.reserve(block->capturesCXXThis() + + (block->capture_end() - block->capture_begin())); + + CharUnits maxFieldAlign; + + // First, 'this'. + if (block->capturesCXXThis()) { + assert(CGF && CGF->CurFuncDecl && isa<CXXMethodDecl>(CGF->CurFuncDecl) && + "Can't capture 'this' outside a method"); + QualType thisType = cast<CXXMethodDecl>(CGF->CurFuncDecl)->getThisType(C); + + // Theoretically, this could be in a different address space, so + // don't assume standard pointer size/align. + llvm::Type *llvmType = CGM.getTypes().ConvertType(thisType); + std::pair<CharUnits,CharUnits> tinfo + = CGM.getContext().getTypeInfoInChars(thisType); + maxFieldAlign = std::max(maxFieldAlign, tinfo.second); + + layout.push_back(BlockLayoutChunk(tinfo.second, tinfo.first, + Qualifiers::OCL_None, + nullptr, llvmType, thisType)); + } + + // Next, all the block captures. + for (const auto &CI : block->captures()) { + const VarDecl *variable = CI.getVariable(); + + if (CI.isByRef()) { + // We have to copy/dispose of the __block reference. + info.NeedsCopyDispose = true; + + // Just use void* instead of a pointer to the byref type. + CharUnits align = CGM.getPointerAlign(); + maxFieldAlign = std::max(maxFieldAlign, align); + + layout.push_back(BlockLayoutChunk(align, CGM.getPointerSize(), + Qualifiers::OCL_None, &CI, + CGM.VoidPtrTy, variable->getType())); + continue; + } + + // Otherwise, build a layout chunk with the size and alignment of + // the declaration. + if (llvm::Constant *constant = tryCaptureAsConstant(CGM, CGF, variable)) { + info.Captures[variable] = CGBlockInfo::Capture::makeConstant(constant); + continue; + } + + // If we have a lifetime qualifier, honor it for capture purposes. + // That includes *not* copying it if it's __unsafe_unretained. + Qualifiers::ObjCLifetime lifetime = + variable->getType().getObjCLifetime(); + if (lifetime) { + switch (lifetime) { + case Qualifiers::OCL_None: llvm_unreachable("impossible"); + case Qualifiers::OCL_ExplicitNone: + case Qualifiers::OCL_Autoreleasing: + break; + + case Qualifiers::OCL_Strong: + case Qualifiers::OCL_Weak: + info.NeedsCopyDispose = true; + } + + // Block pointers require copy/dispose. So do Objective-C pointers. + } else if (variable->getType()->isObjCRetainableType()) { + // But honor the inert __unsafe_unretained qualifier, which doesn't + // actually make it into the type system. + if (variable->getType()->isObjCInertUnsafeUnretainedType()) { + lifetime = Qualifiers::OCL_ExplicitNone; + } else { + info.NeedsCopyDispose = true; + // used for mrr below. + lifetime = Qualifiers::OCL_Strong; + } + + // So do types that require non-trivial copy construction. + } else if (CI.hasCopyExpr()) { + info.NeedsCopyDispose = true; + info.HasCXXObject = true; + + // And so do types with destructors. + } else if (CGM.getLangOpts().CPlusPlus) { + if (const CXXRecordDecl *record = + variable->getType()->getAsCXXRecordDecl()) { + if (!record->hasTrivialDestructor()) { + info.HasCXXObject = true; + info.NeedsCopyDispose = true; + } + } + } + + QualType VT = getCaptureFieldType(*CGF, CI); + CharUnits size = C.getTypeSizeInChars(VT); + CharUnits align = C.getDeclAlign(variable); + + maxFieldAlign = std::max(maxFieldAlign, align); + + llvm::Type *llvmType = + CGM.getTypes().ConvertTypeForMem(VT); + + layout.push_back( + BlockLayoutChunk(align, size, lifetime, &CI, llvmType, VT)); + } + + // If that was everything, we're done here. + if (layout.empty()) { + info.StructureType = + llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); + info.CanBeGlobal = true; + return; + } + + // Sort the layout by alignment. We have to use a stable sort here + // to get reproducible results. There should probably be an + // llvm::array_pod_stable_sort. + std::stable_sort(layout.begin(), layout.end()); + + // Needed for blocks layout info. + info.BlockHeaderForcedGapOffset = info.BlockSize; + info.BlockHeaderForcedGapSize = CharUnits::Zero(); + + CharUnits &blockSize = info.BlockSize; + info.BlockAlign = std::max(maxFieldAlign, info.BlockAlign); + + // Assuming that the first byte in the header is maximally aligned, + // get the alignment of the first byte following the header. + CharUnits endAlign = getLowBit(blockSize); + + // If the end of the header isn't satisfactorily aligned for the + // maximum thing, look for things that are okay with the header-end + // alignment, and keep appending them until we get something that's + // aligned right. This algorithm is only guaranteed optimal if + // that condition is satisfied at some point; otherwise we can get + // things like: + // header // next byte has alignment 4 + // something_with_size_5; // next byte has alignment 1 + // something_with_alignment_8; + // which has 7 bytes of padding, as opposed to the naive solution + // which might have less (?). + if (endAlign < maxFieldAlign) { + SmallVectorImpl<BlockLayoutChunk>::iterator + li = layout.begin() + 1, le = layout.end(); + + // Look for something that the header end is already + // satisfactorily aligned for. + for (; li != le && endAlign < li->Alignment; ++li) + ; + + // If we found something that's naturally aligned for the end of + // the header, keep adding things... + if (li != le) { + SmallVectorImpl<BlockLayoutChunk>::iterator first = li; + for (; li != le; ++li) { + assert(endAlign >= li->Alignment); + + li->setIndex(info, elementTypes.size(), blockSize); + elementTypes.push_back(li->Type); + blockSize += li->Size; + endAlign = getLowBit(blockSize); + + // ...until we get to the alignment of the maximum field. + if (endAlign >= maxFieldAlign) { + break; + } + } + // Don't re-append everything we just appended. + layout.erase(first, li); + } + } + + assert(endAlign == getLowBit(blockSize)); + + // At this point, we just have to add padding if the end align still + // isn't aligned right. + if (endAlign < maxFieldAlign) { + CharUnits newBlockSize = blockSize.alignTo(maxFieldAlign); + CharUnits padding = newBlockSize - blockSize; + + // If we haven't yet added any fields, remember that there was an + // initial gap; this need to go into the block layout bit map. + if (blockSize == info.BlockHeaderForcedGapOffset) { + info.BlockHeaderForcedGapSize = padding; + } + + elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty, + padding.getQuantity())); + blockSize = newBlockSize; + endAlign = getLowBit(blockSize); // might be > maxFieldAlign + } + + assert(endAlign >= maxFieldAlign); + assert(endAlign == getLowBit(blockSize)); + // Slam everything else on now. This works because they have + // strictly decreasing alignment and we expect that size is always a + // multiple of alignment. + for (SmallVectorImpl<BlockLayoutChunk>::iterator + li = layout.begin(), le = layout.end(); li != le; ++li) { + if (endAlign < li->Alignment) { + // size may not be multiple of alignment. This can only happen with + // an over-aligned variable. We will be adding a padding field to + // make the size be multiple of alignment. + CharUnits padding = li->Alignment - endAlign; + elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty, + padding.getQuantity())); + blockSize += padding; + endAlign = getLowBit(blockSize); + } + assert(endAlign >= li->Alignment); + li->setIndex(info, elementTypes.size(), blockSize); + elementTypes.push_back(li->Type); + blockSize += li->Size; + endAlign = getLowBit(blockSize); + } + + info.StructureType = + llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); +} + +/// Enter the scope of a block. This should be run at the entrance to +/// a full-expression so that the block's cleanups are pushed at the +/// right place in the stack. +static void enterBlockScope(CodeGenFunction &CGF, BlockDecl *block) { + assert(CGF.HaveInsertPoint()); + + // Allocate the block info and place it at the head of the list. + CGBlockInfo &blockInfo = + *new CGBlockInfo(block, CGF.CurFn->getName()); + blockInfo.NextBlockInfo = CGF.FirstBlockInfo; + CGF.FirstBlockInfo = &blockInfo; + + // Compute information about the layout, etc., of this block, + // pushing cleanups as necessary. + computeBlockInfo(CGF.CGM, &CGF, blockInfo); + + // Nothing else to do if it can be global. + if (blockInfo.CanBeGlobal) return; + + // Make the allocation for the block. + blockInfo.LocalAddress = CGF.CreateTempAlloca(blockInfo.StructureType, + blockInfo.BlockAlign, "block"); + + // If there are cleanups to emit, enter them (but inactive). + if (!blockInfo.NeedsCopyDispose) return; + + // Walk through the captures (in order) and find the ones not + // captured by constant. + for (const auto &CI : block->captures()) { + // Ignore __block captures; there's nothing special in the + // on-stack block that we need to do for them. + if (CI.isByRef()) continue; + + // Ignore variables that are constant-captured. + const VarDecl *variable = CI.getVariable(); + CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); + if (capture.isConstant()) continue; + + // Ignore objects that aren't destructed. + QualType VT = getCaptureFieldType(CGF, CI); + QualType::DestructionKind dtorKind = VT.isDestructedType(); + if (dtorKind == QualType::DK_none) continue; + + CodeGenFunction::Destroyer *destroyer; + + // Block captures count as local values and have imprecise semantics. + // They also can't be arrays, so need to worry about that. + // + // For const-qualified captures, emit clang.arc.use to ensure the captured + // object doesn't get released while we are still depending on its validity + // within the block. + if (VT.isConstQualified() && + VT.getObjCLifetime() == Qualifiers::OCL_Strong && + CGF.CGM.getCodeGenOpts().OptimizationLevel != 0) { + assert(CGF.CGM.getLangOpts().ObjCAutoRefCount && + "expected ObjC ARC to be enabled"); + destroyer = CodeGenFunction::emitARCIntrinsicUse; + } else if (dtorKind == QualType::DK_objc_strong_lifetime) { + destroyer = CodeGenFunction::destroyARCStrongImprecise; + } else { + destroyer = CGF.getDestroyer(dtorKind); + } + + // GEP down to the address. + Address addr = CGF.Builder.CreateStructGEP(blockInfo.LocalAddress, + capture.getIndex(), + capture.getOffset()); + + // We can use that GEP as the dominating IP. + if (!blockInfo.DominatingIP) + blockInfo.DominatingIP = cast<llvm::Instruction>(addr.getPointer()); + + CleanupKind cleanupKind = InactiveNormalCleanup; + bool useArrayEHCleanup = CGF.needsEHCleanup(dtorKind); + if (useArrayEHCleanup) + cleanupKind = InactiveNormalAndEHCleanup; + + CGF.pushDestroy(cleanupKind, addr, VT, + destroyer, useArrayEHCleanup); + + // Remember where that cleanup was. + capture.setCleanup(CGF.EHStack.stable_begin()); + } +} + +/// Enter a full-expression with a non-trivial number of objects to +/// clean up. This is in this file because, at the moment, the only +/// kind of cleanup object is a BlockDecl*. +void CodeGenFunction::enterNonTrivialFullExpression(const ExprWithCleanups *E) { + assert(E->getNumObjects() != 0); + ArrayRef<ExprWithCleanups::CleanupObject> cleanups = E->getObjects(); + for (ArrayRef<ExprWithCleanups::CleanupObject>::iterator + i = cleanups.begin(), e = cleanups.end(); i != e; ++i) { + enterBlockScope(*this, *i); + } +} + +/// Find the layout for the given block in a linked list and remove it. +static CGBlockInfo *findAndRemoveBlockInfo(CGBlockInfo **head, + const BlockDecl *block) { + while (true) { + assert(head && *head); + CGBlockInfo *cur = *head; + + // If this is the block we're looking for, splice it out of the list. + if (cur->getBlockDecl() == block) { + *head = cur->NextBlockInfo; + return cur; + } + + head = &cur->NextBlockInfo; + } +} + +/// Destroy a chain of block layouts. +void CodeGenFunction::destroyBlockInfos(CGBlockInfo *head) { + assert(head && "destroying an empty chain"); + do { + CGBlockInfo *cur = head; + head = cur->NextBlockInfo; + delete cur; + } while (head != nullptr); +} + +/// Emit a block literal expression in the current function. +llvm::Value *CodeGenFunction::EmitBlockLiteral(const BlockExpr *blockExpr) { + // If the block has no captures, we won't have a pre-computed + // layout for it. + if (!blockExpr->getBlockDecl()->hasCaptures()) { + if (llvm::Constant *Block = CGM.getAddrOfGlobalBlockIfEmitted(blockExpr)) + return Block; + CGBlockInfo blockInfo(blockExpr->getBlockDecl(), CurFn->getName()); + computeBlockInfo(CGM, this, blockInfo); + blockInfo.BlockExpression = blockExpr; + return EmitBlockLiteral(blockInfo); + } + + // Find the block info for this block and take ownership of it. + std::unique_ptr<CGBlockInfo> blockInfo; + blockInfo.reset(findAndRemoveBlockInfo(&FirstBlockInfo, + blockExpr->getBlockDecl())); + + blockInfo->BlockExpression = blockExpr; + return EmitBlockLiteral(*blockInfo); +} + +llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo) { + // Using the computed layout, generate the actual block function. + bool isLambdaConv = blockInfo.getBlockDecl()->isConversionFromLambda(); + llvm::Constant *blockFn + = CodeGenFunction(CGM, true).GenerateBlockFunction(CurGD, blockInfo, + LocalDeclMap, + isLambdaConv); + blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy); + + // If there is nothing to capture, we can emit this as a global block. + if (blockInfo.CanBeGlobal) + return buildGlobalBlock(CGM, blockInfo, blockFn); + + // Otherwise, we have to emit this as a local block. + + llvm::Constant *isa = + (!CGM.getContext().getLangOpts().OpenCL) + ? CGM.getNSConcreteStackBlock() + : CGM.getNullPointer(VoidPtrPtrTy, + CGM.getContext().getPointerType( + QualType(CGM.getContext().VoidPtrTy))); + isa = llvm::ConstantExpr::getBitCast(isa, VoidPtrTy); + + // Build the block descriptor. + llvm::Constant *descriptor = buildBlockDescriptor(CGM, blockInfo); + + Address blockAddr = blockInfo.LocalAddress; + assert(blockAddr.isValid() && "block has no address!"); + + // Compute the initial on-stack block flags. + BlockFlags flags = BLOCK_HAS_SIGNATURE; + if (blockInfo.HasCapturedVariableLayout) flags |= BLOCK_HAS_EXTENDED_LAYOUT; + if (blockInfo.NeedsCopyDispose) flags |= BLOCK_HAS_COPY_DISPOSE; + if (blockInfo.HasCXXObject) flags |= BLOCK_HAS_CXX_OBJ; + if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET; + + auto projectField = + [&](unsigned index, CharUnits offset, const Twine &name) -> Address { + return Builder.CreateStructGEP(blockAddr, index, offset, name); + }; + auto storeField = + [&](llvm::Value *value, unsigned index, CharUnits offset, + const Twine &name) { + Builder.CreateStore(value, projectField(index, offset, name)); + }; + + // Initialize the block header. + { + // We assume all the header fields are densely packed. + unsigned index = 0; + CharUnits offset; + auto addHeaderField = + [&](llvm::Value *value, CharUnits size, const Twine &name) { + storeField(value, index, offset, name); + offset += size; + index++; + }; + + addHeaderField(isa, getPointerSize(), "block.isa"); + addHeaderField(llvm::ConstantInt::get(IntTy, flags.getBitMask()), + getIntSize(), "block.flags"); + addHeaderField(llvm::ConstantInt::get(IntTy, 0), + getIntSize(), "block.reserved"); + addHeaderField(blockFn, getPointerSize(), "block.invoke"); + addHeaderField(descriptor, getPointerSize(), "block.descriptor"); + } + + // Finally, capture all the values into the block. + const BlockDecl *blockDecl = blockInfo.getBlockDecl(); + + // First, 'this'. + if (blockDecl->capturesCXXThis()) { + Address addr = projectField(blockInfo.CXXThisIndex, blockInfo.CXXThisOffset, + "block.captured-this.addr"); + Builder.CreateStore(LoadCXXThis(), addr); + } + + // Next, captured variables. + for (const auto &CI : blockDecl->captures()) { + const VarDecl *variable = CI.getVariable(); + const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); + + // Ignore constant captures. + if (capture.isConstant()) continue; + + QualType type = capture.fieldType(); + + // This will be a [[type]]*, except that a byref entry will just be + // an i8**. + Address blockField = + projectField(capture.getIndex(), capture.getOffset(), "block.captured"); + + // Compute the address of the thing we're going to move into the + // block literal. + Address src = Address::invalid(); + + if (blockDecl->isConversionFromLambda()) { + // The lambda capture in a lambda's conversion-to-block-pointer is + // special; we'll simply emit it directly. + src = Address::invalid(); + } else if (CI.isByRef()) { + if (BlockInfo && CI.isNested()) { + // We need to use the capture from the enclosing block. + const CGBlockInfo::Capture &enclosingCapture = + BlockInfo->getCapture(variable); + + // This is a [[type]]*, except that a byref entry wil just be an i8**. + src = Builder.CreateStructGEP(LoadBlockStruct(), + enclosingCapture.getIndex(), + enclosingCapture.getOffset(), + "block.capture.addr"); + } else { + auto I = LocalDeclMap.find(variable); + assert(I != LocalDeclMap.end()); + src = I->second; + } + } else { + DeclRefExpr declRef(const_cast<VarDecl *>(variable), + /*RefersToEnclosingVariableOrCapture*/ CI.isNested(), + type.getNonReferenceType(), VK_LValue, + SourceLocation()); + src = EmitDeclRefLValue(&declRef).getAddress(); + }; + + // For byrefs, we just write the pointer to the byref struct into + // the block field. There's no need to chase the forwarding + // pointer at this point, since we're building something that will + // live a shorter life than the stack byref anyway. + if (CI.isByRef()) { + // Get a void* that points to the byref struct. + llvm::Value *byrefPointer; + if (CI.isNested()) + byrefPointer = Builder.CreateLoad(src, "byref.capture"); + else + byrefPointer = Builder.CreateBitCast(src.getPointer(), VoidPtrTy); + + // Write that void* into the capture field. + Builder.CreateStore(byrefPointer, blockField); + + // If we have a copy constructor, evaluate that into the block field. + } else if (const Expr *copyExpr = CI.getCopyExpr()) { + if (blockDecl->isConversionFromLambda()) { + // If we have a lambda conversion, emit the expression + // directly into the block instead. + AggValueSlot Slot = + AggValueSlot::forAddr(blockField, Qualifiers(), + AggValueSlot::IsDestructed, + AggValueSlot::DoesNotNeedGCBarriers, + AggValueSlot::IsNotAliased); + EmitAggExpr(copyExpr, Slot); + } else { + EmitSynthesizedCXXCopyCtor(blockField, src, copyExpr); + } + + // If it's a reference variable, copy the reference into the block field. + } else if (type->isReferenceType()) { + Builder.CreateStore(src.getPointer(), blockField); + + // If type is const-qualified, copy the value into the block field. + } else if (type.isConstQualified() && + type.getObjCLifetime() == Qualifiers::OCL_Strong && + CGM.getCodeGenOpts().OptimizationLevel != 0) { + llvm::Value *value = Builder.CreateLoad(src, "captured"); + Builder.CreateStore(value, blockField); + + // If this is an ARC __strong block-pointer variable, don't do a + // block copy. + // + // TODO: this can be generalized into the normal initialization logic: + // we should never need to do a block-copy when initializing a local + // variable, because the local variable's lifetime should be strictly + // contained within the stack block's. + } else if (type.getObjCLifetime() == Qualifiers::OCL_Strong && + type->isBlockPointerType()) { + // Load the block and do a simple retain. + llvm::Value *value = Builder.CreateLoad(src, "block.captured_block"); + value = EmitARCRetainNonBlock(value); + + // Do a primitive store to the block field. + Builder.CreateStore(value, blockField); + + // Otherwise, fake up a POD copy into the block field. + } else { + // Fake up a new variable so that EmitScalarInit doesn't think + // we're referring to the variable in its own initializer. + ImplicitParamDecl BlockFieldPseudoVar(getContext(), type, + ImplicitParamDecl::Other); + + // We use one of these or the other depending on whether the + // reference is nested. + DeclRefExpr declRef(const_cast<VarDecl *>(variable), + /*RefersToEnclosingVariableOrCapture*/ CI.isNested(), + type, VK_LValue, SourceLocation()); + + ImplicitCastExpr l2r(ImplicitCastExpr::OnStack, type, CK_LValueToRValue, + &declRef, VK_RValue); + // FIXME: Pass a specific location for the expr init so that the store is + // attributed to a reasonable location - otherwise it may be attributed to + // locations of subexpressions in the initialization. + LValueBaseInfo BaseInfo(AlignmentSource::Decl, false); + EmitExprAsInit(&l2r, &BlockFieldPseudoVar, + MakeAddrLValue(blockField, type, BaseInfo), + /*captured by init*/ false); + } + + // Activate the cleanup if layout pushed one. + if (!CI.isByRef()) { + EHScopeStack::stable_iterator cleanup = capture.getCleanup(); + if (cleanup.isValid()) + ActivateCleanupBlock(cleanup, blockInfo.DominatingIP); + } + } + + // Cast to the converted block-pointer type, which happens (somewhat + // unfortunately) to be a pointer to function type. + llvm::Value *result = Builder.CreatePointerCast( + blockAddr.getPointer(), ConvertType(blockInfo.getBlockExpr()->getType())); + + return result; +} + + +llvm::Type *CodeGenModule::getBlockDescriptorType() { + if (BlockDescriptorType) + return BlockDescriptorType; + + llvm::Type *UnsignedLongTy = + getTypes().ConvertType(getContext().UnsignedLongTy); + + // struct __block_descriptor { + // unsigned long reserved; + // unsigned long block_size; + // + // // later, the following will be added + // + // struct { + // void (*copyHelper)(); + // void (*copyHelper)(); + // } helpers; // !!! optional + // + // const char *signature; // the block signature + // const char *layout; // reserved + // }; + BlockDescriptorType = llvm::StructType::create( + "struct.__block_descriptor", UnsignedLongTy, UnsignedLongTy); + + // Now form a pointer to that. + unsigned AddrSpace = 0; + if (getLangOpts().OpenCL) + AddrSpace = getContext().getTargetAddressSpace(LangAS::opencl_constant); + BlockDescriptorType = llvm::PointerType::get(BlockDescriptorType, AddrSpace); + return BlockDescriptorType; +} + +llvm::Type *CodeGenModule::getGenericBlockLiteralType() { + if (GenericBlockLiteralType) + return GenericBlockLiteralType; + + llvm::Type *BlockDescPtrTy = getBlockDescriptorType(); + + // struct __block_literal_generic { + // void *__isa; + // int __flags; + // int __reserved; + // void (*__invoke)(void *); + // struct __block_descriptor *__descriptor; + // }; + GenericBlockLiteralType = + llvm::StructType::create("struct.__block_literal_generic", VoidPtrTy, + IntTy, IntTy, VoidPtrTy, BlockDescPtrTy); + + return GenericBlockLiteralType; +} + +RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr *E, + ReturnValueSlot ReturnValue) { + const BlockPointerType *BPT = + E->getCallee()->getType()->getAs<BlockPointerType>(); + + llvm::Value *BlockPtr = EmitScalarExpr(E->getCallee()); + + // Get a pointer to the generic block literal. + // For OpenCL we generate generic AS void ptr to be able to reuse the same + // block definition for blocks with captures generated as private AS local + // variables and without captures generated as global AS program scope + // variables. + unsigned AddrSpace = 0; + if (getLangOpts().OpenCL) + AddrSpace = getContext().getTargetAddressSpace(LangAS::opencl_generic); + + llvm::Type *BlockLiteralTy = + llvm::PointerType::get(CGM.getGenericBlockLiteralType(), AddrSpace); + + // Bitcast the callee to a block literal. + BlockPtr = + Builder.CreatePointerCast(BlockPtr, BlockLiteralTy, "block.literal"); + + // Get the function pointer from the literal. + llvm::Value *FuncPtr = + Builder.CreateStructGEP(CGM.getGenericBlockLiteralType(), BlockPtr, 3); + + + // Add the block literal. + CallArgList Args; + + QualType VoidPtrQualTy = getContext().VoidPtrTy; + llvm::Type *GenericVoidPtrTy = VoidPtrTy; + if (getLangOpts().OpenCL) { + GenericVoidPtrTy = Builder.getInt8PtrTy( + getContext().getTargetAddressSpace(LangAS::opencl_generic)); + VoidPtrQualTy = + getContext().getPointerType(getContext().getAddrSpaceQualType( + getContext().VoidTy, LangAS::opencl_generic)); + } + + BlockPtr = Builder.CreatePointerCast(BlockPtr, GenericVoidPtrTy); + Args.add(RValue::get(BlockPtr), VoidPtrQualTy); + + QualType FnType = BPT->getPointeeType(); + + // And the rest of the arguments. + EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(), E->arguments()); + + // Load the function. + llvm::Value *Func = Builder.CreateAlignedLoad(FuncPtr, getPointerAlign()); + + const FunctionType *FuncTy = FnType->castAs<FunctionType>(); + const CGFunctionInfo &FnInfo = + CGM.getTypes().arrangeBlockFunctionCall(Args, FuncTy); + + // Cast the function pointer to the right type. + llvm::Type *BlockFTy = CGM.getTypes().GetFunctionType(FnInfo); + + llvm::Type *BlockFTyPtr = llvm::PointerType::getUnqual(BlockFTy); + Func = Builder.CreateBitCast(Func, BlockFTyPtr); + + // Prepare the callee. + CGCallee Callee(CGCalleeInfo(), Func); + + // And call the block. + return EmitCall(FnInfo, Callee, ReturnValue, Args); +} + +Address CodeGenFunction::GetAddrOfBlockDecl(const VarDecl *variable, + bool isByRef) { + assert(BlockInfo && "evaluating block ref without block information?"); + const CGBlockInfo::Capture &capture = BlockInfo->getCapture(variable); + + // Handle constant captures. + if (capture.isConstant()) return LocalDeclMap.find(variable)->second; + + Address addr = + Builder.CreateStructGEP(LoadBlockStruct(), capture.getIndex(), + capture.getOffset(), "block.capture.addr"); + + if (isByRef) { + // addr should be a void** right now. Load, then cast the result + // to byref*. + + auto &byrefInfo = getBlockByrefInfo(variable); + addr = Address(Builder.CreateLoad(addr), byrefInfo.ByrefAlignment); + + auto byrefPointerType = llvm::PointerType::get(byrefInfo.Type, 0); + addr = Builder.CreateBitCast(addr, byrefPointerType, "byref.addr"); + + addr = emitBlockByrefAddress(addr, byrefInfo, /*follow*/ true, + variable->getName()); + } + + if (auto refType = capture.fieldType()->getAs<ReferenceType>()) + addr = EmitLoadOfReference(addr, refType); + + return addr; +} + +void CodeGenModule::setAddrOfGlobalBlock(const BlockExpr *BE, + llvm::Constant *Addr) { + bool Ok = EmittedGlobalBlocks.insert(std::make_pair(BE, Addr)).second; + (void)Ok; + assert(Ok && "Trying to replace an already-existing global block!"); +} + +llvm::Constant * +CodeGenModule::GetAddrOfGlobalBlock(const BlockExpr *BE, + StringRef Name) { + if (llvm::Constant *Block = getAddrOfGlobalBlockIfEmitted(BE)) + return Block; + + CGBlockInfo blockInfo(BE->getBlockDecl(), Name); + blockInfo.BlockExpression = BE; + + // Compute information about the layout, etc., of this block. + computeBlockInfo(*this, nullptr, blockInfo); + + // Using that metadata, generate the actual block function. + llvm::Constant *blockFn; + { + CodeGenFunction::DeclMapTy LocalDeclMap; + blockFn = CodeGenFunction(*this).GenerateBlockFunction(GlobalDecl(), + blockInfo, + LocalDeclMap, + false); + } + blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy); + + return buildGlobalBlock(*this, blockInfo, blockFn); +} + +static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM, + const CGBlockInfo &blockInfo, + llvm::Constant *blockFn) { + assert(blockInfo.CanBeGlobal); + // Callers should detect this case on their own: calling this function + // generally requires computing layout information, which is a waste of time + // if we've already emitted this block. + assert(!CGM.getAddrOfGlobalBlockIfEmitted(blockInfo.BlockExpression) && + "Refusing to re-emit a global block."); + + // Generate the constants for the block literal initializer. + ConstantInitBuilder builder(CGM); + auto fields = builder.beginStruct(); + + // isa + fields.add((!CGM.getContext().getLangOpts().OpenCL) + ? CGM.getNSConcreteGlobalBlock() + : CGM.getNullPointer(CGM.VoidPtrPtrTy, + CGM.getContext().getPointerType(QualType( + CGM.getContext().VoidPtrTy)))); + + // __flags + BlockFlags flags = BLOCK_IS_GLOBAL | BLOCK_HAS_SIGNATURE; + if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET; + + fields.addInt(CGM.IntTy, flags.getBitMask()); + + // Reserved + fields.addInt(CGM.IntTy, 0); + + // Function + fields.add(blockFn); + + // Descriptor + fields.add(buildBlockDescriptor(CGM, blockInfo)); + + unsigned AddrSpace = 0; + if (CGM.getContext().getLangOpts().OpenCL) + AddrSpace = CGM.getContext().getTargetAddressSpace(LangAS::opencl_global); + + llvm::Constant *literal = fields.finishAndCreateGlobal( + "__block_literal_global", blockInfo.BlockAlign, + /*constant*/ true, llvm::GlobalVariable::InternalLinkage, AddrSpace); + + // Return a constant of the appropriately-casted type. + llvm::Type *RequiredType = + CGM.getTypes().ConvertType(blockInfo.getBlockExpr()->getType()); + llvm::Constant *Result = + llvm::ConstantExpr::getPointerCast(literal, RequiredType); + CGM.setAddrOfGlobalBlock(blockInfo.BlockExpression, Result); + return Result; +} + +void CodeGenFunction::setBlockContextParameter(const ImplicitParamDecl *D, + unsigned argNum, + llvm::Value *arg) { + assert(BlockInfo && "not emitting prologue of block invocation function?!"); + + llvm::Value *localAddr = nullptr; + if (CGM.getCodeGenOpts().OptimizationLevel == 0) { + // Allocate a stack slot to let the debug info survive the RA. + Address alloc = CreateMemTemp(D->getType(), D->getName() + ".addr"); + Builder.CreateStore(arg, alloc); + localAddr = Builder.CreateLoad(alloc); + } + + if (CGDebugInfo *DI = getDebugInfo()) { + if (CGM.getCodeGenOpts().getDebugInfo() >= + codegenoptions::LimitedDebugInfo) { + DI->setLocation(D->getLocation()); + DI->EmitDeclareOfBlockLiteralArgVariable(*BlockInfo, arg, argNum, + localAddr, Builder); + } + } + + SourceLocation StartLoc = BlockInfo->getBlockExpr()->getBody()->getLocStart(); + ApplyDebugLocation Scope(*this, StartLoc); + + // Instead of messing around with LocalDeclMap, just set the value + // directly as BlockPointer. + BlockPointer = Builder.CreatePointerCast( + arg, + BlockInfo->StructureType->getPointerTo( + getContext().getLangOpts().OpenCL + ? getContext().getTargetAddressSpace(LangAS::opencl_generic) + : 0), + "block"); +} + +Address CodeGenFunction::LoadBlockStruct() { + assert(BlockInfo && "not in a block invocation function!"); + assert(BlockPointer && "no block pointer set!"); + return Address(BlockPointer, BlockInfo->BlockAlign); +} + +llvm::Function * +CodeGenFunction::GenerateBlockFunction(GlobalDecl GD, + const CGBlockInfo &blockInfo, + const DeclMapTy &ldm, + bool IsLambdaConversionToBlock) { + const BlockDecl *blockDecl = blockInfo.getBlockDecl(); + + CurGD = GD; + + CurEHLocation = blockInfo.getBlockExpr()->getLocEnd(); + + BlockInfo = &blockInfo; + + // Arrange for local static and local extern declarations to appear + // to be local to this function as well, in case they're directly + // referenced in a block. + for (DeclMapTy::const_iterator i = ldm.begin(), e = ldm.end(); i != e; ++i) { + const auto *var = dyn_cast<VarDecl>(i->first); + if (var && !var->hasLocalStorage()) + setAddrOfLocalVar(var, i->second); + } + + // Begin building the function declaration. + + // Build the argument list. + FunctionArgList args; + + // The first argument is the block pointer. Just take it as a void* + // and cast it later. + QualType selfTy = getContext().VoidPtrTy; + + // For OpenCL passed block pointer can be private AS local variable or + // global AS program scope variable (for the case with and without captures). + // Generic AS is used therefore to be able to accommodate both private and + // generic AS in one implementation. + if (getLangOpts().OpenCL) + selfTy = getContext().getPointerType(getContext().getAddrSpaceQualType( + getContext().VoidTy, LangAS::opencl_generic)); + + IdentifierInfo *II = &CGM.getContext().Idents.get(".block_descriptor"); + + ImplicitParamDecl SelfDecl(getContext(), const_cast<BlockDecl *>(blockDecl), + SourceLocation(), II, selfTy, + ImplicitParamDecl::ObjCSelf); + args.push_back(&SelfDecl); + + // Now add the rest of the parameters. + args.append(blockDecl->param_begin(), blockDecl->param_end()); + + // Create the function declaration. + const FunctionProtoType *fnType = blockInfo.getBlockExpr()->getFunctionType(); + const CGFunctionInfo &fnInfo = + CGM.getTypes().arrangeBlockFunctionDeclaration(fnType, args); + if (CGM.ReturnSlotInterferesWithArgs(fnInfo)) + blockInfo.UsesStret = true; + + llvm::FunctionType *fnLLVMType = CGM.getTypes().GetFunctionType(fnInfo); + + StringRef name = CGM.getBlockMangledName(GD, blockDecl); + llvm::Function *fn = llvm::Function::Create( + fnLLVMType, llvm::GlobalValue::InternalLinkage, name, &CGM.getModule()); + CGM.SetInternalFunctionAttributes(blockDecl, fn, fnInfo); + + // Begin generating the function. + StartFunction(blockDecl, fnType->getReturnType(), fn, fnInfo, args, + blockDecl->getLocation(), + blockInfo.getBlockExpr()->getBody()->getLocStart()); + + // Okay. Undo some of what StartFunction did. + + // At -O0 we generate an explicit alloca for the BlockPointer, so the RA + // won't delete the dbg.declare intrinsics for captured variables. + llvm::Value *BlockPointerDbgLoc = BlockPointer; + if (CGM.getCodeGenOpts().OptimizationLevel == 0) { + // Allocate a stack slot for it, so we can point the debugger to it + Address Alloca = CreateTempAlloca(BlockPointer->getType(), + getPointerAlign(), + "block.addr"); + // Set the DebugLocation to empty, so the store is recognized as a + // frame setup instruction by llvm::DwarfDebug::beginFunction(). + auto NL = ApplyDebugLocation::CreateEmpty(*this); + Builder.CreateStore(BlockPointer, Alloca); + BlockPointerDbgLoc = Alloca.getPointer(); + } + + // If we have a C++ 'this' reference, go ahead and force it into + // existence now. + if (blockDecl->capturesCXXThis()) { + Address addr = + Builder.CreateStructGEP(LoadBlockStruct(), blockInfo.CXXThisIndex, + blockInfo.CXXThisOffset, "block.captured-this"); + CXXThisValue = Builder.CreateLoad(addr, "this"); + } + + // Also force all the constant captures. + for (const auto &CI : blockDecl->captures()) { + const VarDecl *variable = CI.getVariable(); + const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); + if (!capture.isConstant()) continue; + + CharUnits align = getContext().getDeclAlign(variable); + Address alloca = + CreateMemTemp(variable->getType(), align, "block.captured-const"); + + Builder.CreateStore(capture.getConstant(), alloca); + + setAddrOfLocalVar(variable, alloca); + } + + // Save a spot to insert the debug information for all the DeclRefExprs. + llvm::BasicBlock *entry = Builder.GetInsertBlock(); + llvm::BasicBlock::iterator entry_ptr = Builder.GetInsertPoint(); + --entry_ptr; + + if (IsLambdaConversionToBlock) + EmitLambdaBlockInvokeBody(); + else { + PGO.assignRegionCounters(GlobalDecl(blockDecl), fn); + incrementProfileCounter(blockDecl->getBody()); + EmitStmt(blockDecl->getBody()); + } + + // Remember where we were... + llvm::BasicBlock *resume = Builder.GetInsertBlock(); + + // Go back to the entry. + ++entry_ptr; + Builder.SetInsertPoint(entry, entry_ptr); + + // Emit debug information for all the DeclRefExprs. + // FIXME: also for 'this' + if (CGDebugInfo *DI = getDebugInfo()) { + for (const auto &CI : blockDecl->captures()) { + const VarDecl *variable = CI.getVariable(); + DI->EmitLocation(Builder, variable->getLocation()); + + if (CGM.getCodeGenOpts().getDebugInfo() >= + codegenoptions::LimitedDebugInfo) { + const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); + if (capture.isConstant()) { + auto addr = LocalDeclMap.find(variable)->second; + DI->EmitDeclareOfAutoVariable(variable, addr.getPointer(), + Builder); + continue; + } + + DI->EmitDeclareOfBlockDeclRefVariable( + variable, BlockPointerDbgLoc, Builder, blockInfo, + entry_ptr == entry->end() ? nullptr : &*entry_ptr); + } + } + // Recover location if it was changed in the above loop. + DI->EmitLocation(Builder, + cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc()); + } + + // And resume where we left off. + if (resume == nullptr) + Builder.ClearInsertionPoint(); + else + Builder.SetInsertPoint(resume); + + FinishFunction(cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc()); + + return fn; +} + +namespace { + +/// Represents a type of copy/destroy operation that should be performed for an +/// entity that's captured by a block. +enum class BlockCaptureEntityKind { + CXXRecord, // Copy or destroy + ARCWeak, + ARCStrong, + BlockObject, // Assign or release + None +}; + +/// Represents a captured entity that requires extra operations in order for +/// this entity to be copied or destroyed correctly. +struct BlockCaptureManagedEntity { + BlockCaptureEntityKind Kind; + BlockFieldFlags Flags; + const BlockDecl::Capture &CI; + const CGBlockInfo::Capture &Capture; + + BlockCaptureManagedEntity(BlockCaptureEntityKind Type, BlockFieldFlags Flags, + const BlockDecl::Capture &CI, + const CGBlockInfo::Capture &Capture) + : Kind(Type), Flags(Flags), CI(CI), Capture(Capture) {} +}; + +} // end anonymous namespace + +static std::pair<BlockCaptureEntityKind, BlockFieldFlags> +computeCopyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T, + const LangOptions &LangOpts) { + if (CI.getCopyExpr()) { + assert(!CI.isByRef()); + // don't bother computing flags + return std::make_pair(BlockCaptureEntityKind::CXXRecord, BlockFieldFlags()); + } + BlockFieldFlags Flags; + if (CI.isByRef()) { + Flags = BLOCK_FIELD_IS_BYREF; + if (T.isObjCGCWeak()) + Flags |= BLOCK_FIELD_IS_WEAK; + return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags); + } + if (!T->isObjCRetainableType()) + // For all other types, the memcpy is fine. + return std::make_pair(BlockCaptureEntityKind::None, Flags); + + Flags = BLOCK_FIELD_IS_OBJECT; + bool isBlockPointer = T->isBlockPointerType(); + if (isBlockPointer) + Flags = BLOCK_FIELD_IS_BLOCK; + + // Special rules for ARC captures: + Qualifiers QS = T.getQualifiers(); + + // We need to register __weak direct captures with the runtime. + if (QS.getObjCLifetime() == Qualifiers::OCL_Weak) + return std::make_pair(BlockCaptureEntityKind::ARCWeak, Flags); + + // We need to retain the copied value for __strong direct captures. + if (QS.getObjCLifetime() == Qualifiers::OCL_Strong) { + // If it's a block pointer, we have to copy the block and + // assign that to the destination pointer, so we might as + // well use _Block_object_assign. Otherwise we can avoid that. + return std::make_pair(!isBlockPointer ? BlockCaptureEntityKind::ARCStrong + : BlockCaptureEntityKind::BlockObject, + Flags); + } + + // Non-ARC captures of retainable pointers are strong and + // therefore require a call to _Block_object_assign. + if (!QS.getObjCLifetime() && !LangOpts.ObjCAutoRefCount) + return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags); + + // Otherwise the memcpy is fine. + return std::make_pair(BlockCaptureEntityKind::None, Flags); +} + +/// Find the set of block captures that need to be explicitly copied or destroy. +static void findBlockCapturedManagedEntities( + const CGBlockInfo &BlockInfo, const LangOptions &LangOpts, + SmallVectorImpl<BlockCaptureManagedEntity> &ManagedCaptures, + llvm::function_ref<std::pair<BlockCaptureEntityKind, BlockFieldFlags>( + const BlockDecl::Capture &, QualType, const LangOptions &)> + Predicate) { + for (const auto &CI : BlockInfo.getBlockDecl()->captures()) { + const VarDecl *Variable = CI.getVariable(); + const CGBlockInfo::Capture &Capture = BlockInfo.getCapture(Variable); + if (Capture.isConstant()) + continue; + + auto Info = Predicate(CI, Variable->getType(), LangOpts); + if (Info.first != BlockCaptureEntityKind::None) + ManagedCaptures.emplace_back(Info.first, Info.second, CI, Capture); + } +} + +/// Generate the copy-helper function for a block closure object: +/// static void block_copy_helper(block_t *dst, block_t *src); +/// The runtime will have previously initialized 'dst' by doing a +/// bit-copy of 'src'. +/// +/// Note that this copies an entire block closure object to the heap; +/// it should not be confused with a 'byref copy helper', which moves +/// the contents of an individual __block variable to the heap. +llvm::Constant * +CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) { + ASTContext &C = getContext(); + + FunctionArgList args; + ImplicitParamDecl DstDecl(getContext(), C.VoidPtrTy, + ImplicitParamDecl::Other); + args.push_back(&DstDecl); + ImplicitParamDecl SrcDecl(getContext(), C.VoidPtrTy, + ImplicitParamDecl::Other); + args.push_back(&SrcDecl); + + const CGFunctionInfo &FI = + CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, args); + + // FIXME: it would be nice if these were mergeable with things with + // identical semantics. + llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI); + + llvm::Function *Fn = + llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, + "__copy_helper_block_", &CGM.getModule()); + + IdentifierInfo *II + = &CGM.getContext().Idents.get("__copy_helper_block_"); + + FunctionDecl *FD = FunctionDecl::Create(C, + C.getTranslationUnitDecl(), + SourceLocation(), + SourceLocation(), II, C.VoidTy, + nullptr, SC_Static, + false, + false); + + CGM.SetInternalFunctionAttributes(nullptr, Fn, FI); + + auto NL = ApplyDebugLocation::CreateEmpty(*this); + StartFunction(FD, C.VoidTy, Fn, FI, args); + // Create a scope with an artificial location for the body of this function. + auto AL = ApplyDebugLocation::CreateArtificial(*this); + llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo(); + + Address src = GetAddrOfLocalVar(&SrcDecl); + src = Address(Builder.CreateLoad(src), blockInfo.BlockAlign); + src = Builder.CreateBitCast(src, structPtrTy, "block.source"); + + Address dst = GetAddrOfLocalVar(&DstDecl); + dst = Address(Builder.CreateLoad(dst), blockInfo.BlockAlign); + dst = Builder.CreateBitCast(dst, structPtrTy, "block.dest"); + + SmallVector<BlockCaptureManagedEntity, 4> CopiedCaptures; + findBlockCapturedManagedEntities(blockInfo, getLangOpts(), CopiedCaptures, + computeCopyInfoForBlockCapture); + + for (const auto &CopiedCapture : CopiedCaptures) { + const BlockDecl::Capture &CI = CopiedCapture.CI; + const CGBlockInfo::Capture &capture = CopiedCapture.Capture; + BlockFieldFlags flags = CopiedCapture.Flags; + + unsigned index = capture.getIndex(); + Address srcField = Builder.CreateStructGEP(src, index, capture.getOffset()); + Address dstField = Builder.CreateStructGEP(dst, index, capture.getOffset()); + + // If there's an explicit copy expression, we do that. + if (CI.getCopyExpr()) { + assert(CopiedCapture.Kind == BlockCaptureEntityKind::CXXRecord); + EmitSynthesizedCXXCopyCtor(dstField, srcField, CI.getCopyExpr()); + } else if (CopiedCapture.Kind == BlockCaptureEntityKind::ARCWeak) { + EmitARCCopyWeak(dstField, srcField); + } else { + llvm::Value *srcValue = Builder.CreateLoad(srcField, "blockcopy.src"); + if (CopiedCapture.Kind == BlockCaptureEntityKind::ARCStrong) { + // At -O0, store null into the destination field (so that the + // storeStrong doesn't over-release) and then call storeStrong. + // This is a workaround to not having an initStrong call. + if (CGM.getCodeGenOpts().OptimizationLevel == 0) { + auto *ty = cast<llvm::PointerType>(srcValue->getType()); + llvm::Value *null = llvm::ConstantPointerNull::get(ty); + Builder.CreateStore(null, dstField); + EmitARCStoreStrongCall(dstField, srcValue, true); + + // With optimization enabled, take advantage of the fact that + // the blocks runtime guarantees a memcpy of the block data, and + // just emit a retain of the src field. + } else { + EmitARCRetainNonBlock(srcValue); + + // We don't need this anymore, so kill it. It's not quite + // worth the annoyance to avoid creating it in the first place. + cast<llvm::Instruction>(dstField.getPointer())->eraseFromParent(); + } + } else { + assert(CopiedCapture.Kind == BlockCaptureEntityKind::BlockObject); + srcValue = Builder.CreateBitCast(srcValue, VoidPtrTy); + llvm::Value *dstAddr = + Builder.CreateBitCast(dstField.getPointer(), VoidPtrTy); + llvm::Value *args[] = { + dstAddr, srcValue, llvm::ConstantInt::get(Int32Ty, flags.getBitMask()) + }; + + const VarDecl *variable = CI.getVariable(); + bool copyCanThrow = false; + if (CI.isByRef() && variable->getType()->getAsCXXRecordDecl()) { + const Expr *copyExpr = + CGM.getContext().getBlockVarCopyInits(variable); + if (copyExpr) { + copyCanThrow = true; // FIXME: reuse the noexcept logic + } + } + + if (copyCanThrow) { + EmitRuntimeCallOrInvoke(CGM.getBlockObjectAssign(), args); + } else { + EmitNounwindRuntimeCall(CGM.getBlockObjectAssign(), args); + } + } + } + } + + FinishFunction(); + + return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy); +} + +static std::pair<BlockCaptureEntityKind, BlockFieldFlags> +computeDestroyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T, + const LangOptions &LangOpts) { + BlockFieldFlags Flags; + if (CI.isByRef()) { + Flags = BLOCK_FIELD_IS_BYREF; + if (T.isObjCGCWeak()) + Flags |= BLOCK_FIELD_IS_WEAK; + return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags); + } + + if (const CXXRecordDecl *Record = T->getAsCXXRecordDecl()) { + if (Record->hasTrivialDestructor()) + return std::make_pair(BlockCaptureEntityKind::None, BlockFieldFlags()); + return std::make_pair(BlockCaptureEntityKind::CXXRecord, BlockFieldFlags()); + } + + // Other types don't need to be destroy explicitly. + if (!T->isObjCRetainableType()) + return std::make_pair(BlockCaptureEntityKind::None, Flags); + + Flags = BLOCK_FIELD_IS_OBJECT; + if (T->isBlockPointerType()) + Flags = BLOCK_FIELD_IS_BLOCK; + + // Special rules for ARC captures. + Qualifiers QS = T.getQualifiers(); + + // Use objc_storeStrong for __strong direct captures; the + // dynamic tools really like it when we do this. + if (QS.getObjCLifetime() == Qualifiers::OCL_Strong) + return std::make_pair(BlockCaptureEntityKind::ARCStrong, Flags); + + // Support __weak direct captures. + if (QS.getObjCLifetime() == Qualifiers::OCL_Weak) + return std::make_pair(BlockCaptureEntityKind::ARCWeak, Flags); + + // Non-ARC captures are strong, and we need to use + // _Block_object_dispose. + if (!QS.hasObjCLifetime() && !LangOpts.ObjCAutoRefCount) + return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags); + + // Otherwise, we have nothing to do. + return std::make_pair(BlockCaptureEntityKind::None, Flags); +} + +/// Generate the destroy-helper function for a block closure object: +/// static void block_destroy_helper(block_t *theBlock); +/// +/// Note that this destroys a heap-allocated block closure object; +/// it should not be confused with a 'byref destroy helper', which +/// destroys the heap-allocated contents of an individual __block +/// variable. +llvm::Constant * +CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) { + ASTContext &C = getContext(); + + FunctionArgList args; + ImplicitParamDecl SrcDecl(getContext(), C.VoidPtrTy, + ImplicitParamDecl::Other); + args.push_back(&SrcDecl); + + const CGFunctionInfo &FI = + CGM.getTypes().arrangeBuiltinFunctionDeclaration(C.VoidTy, args); + + // FIXME: We'd like to put these into a mergable by content, with + // internal linkage. + llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI); + + llvm::Function *Fn = + llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, + "__destroy_helper_block_", &CGM.getModule()); + + IdentifierInfo *II + = &CGM.getContext().Idents.get("__destroy_helper_block_"); + + FunctionDecl *FD = FunctionDecl::Create(C, C.getTranslationUnitDecl(), + SourceLocation(), + SourceLocation(), II, C.VoidTy, + nullptr, SC_Static, + false, false); + + CGM.SetInternalFunctionAttributes(nullptr, Fn, FI); + + // Create a scope with an artificial location for the body of this function. + auto NL = ApplyDebugLocation::CreateEmpty(*this); + StartFunction(FD, C.VoidTy, Fn, FI, args); + auto AL = ApplyDebugLocation::CreateArtificial(*this); + + llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo(); + + Address src = GetAddrOfLocalVar(&SrcDecl); + src = Address(Builder.CreateLoad(src), blockInfo.BlockAlign); + src = Builder.CreateBitCast(src, structPtrTy, "block"); + + CodeGenFunction::RunCleanupsScope cleanups(*this); + + SmallVector<BlockCaptureManagedEntity, 4> DestroyedCaptures; + findBlockCapturedManagedEntities(blockInfo, getLangOpts(), DestroyedCaptures, + computeDestroyInfoForBlockCapture); + + for (const auto &DestroyedCapture : DestroyedCaptures) { + const BlockDecl::Capture &CI = DestroyedCapture.CI; + const CGBlockInfo::Capture &capture = DestroyedCapture.Capture; + BlockFieldFlags flags = DestroyedCapture.Flags; + + Address srcField = + Builder.CreateStructGEP(src, capture.getIndex(), capture.getOffset()); + + // If the captured record has a destructor then call it. + if (DestroyedCapture.Kind == BlockCaptureEntityKind::CXXRecord) { + const auto *Dtor = + CI.getVariable()->getType()->getAsCXXRecordDecl()->getDestructor(); + PushDestructorCleanup(Dtor, srcField); + + // If this is a __weak capture, emit the release directly. + } else if (DestroyedCapture.Kind == BlockCaptureEntityKind::ARCWeak) { + EmitARCDestroyWeak(srcField); + + // Destroy strong objects with a call if requested. + } else if (DestroyedCapture.Kind == BlockCaptureEntityKind::ARCStrong) { + EmitARCDestroyStrong(srcField, ARCImpreciseLifetime); + + // Otherwise we call _Block_object_dispose. It wouldn't be too + // hard to just emit this as a cleanup if we wanted to make sure + // that things were done in reverse. + } else { + assert(DestroyedCapture.Kind == BlockCaptureEntityKind::BlockObject); + llvm::Value *value = Builder.CreateLoad(srcField); + value = Builder.CreateBitCast(value, VoidPtrTy); + BuildBlockRelease(value, flags); + } + } + + cleanups.ForceCleanup(); + + FinishFunction(); + + return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy); +} + +namespace { + +/// Emits the copy/dispose helper functions for a __block object of id type. +class ObjectByrefHelpers final : public BlockByrefHelpers { + BlockFieldFlags Flags; + +public: + ObjectByrefHelpers(CharUnits alignment, BlockFieldFlags flags) + : BlockByrefHelpers(alignment), Flags(flags) {} + + void emitCopy(CodeGenFunction &CGF, Address destField, + Address srcField) override { + destField = CGF.Builder.CreateBitCast(destField, CGF.VoidPtrTy); + + srcField = CGF.Builder.CreateBitCast(srcField, CGF.VoidPtrPtrTy); + llvm::Value *srcValue = CGF.Builder.CreateLoad(srcField); + + unsigned flags = (Flags | BLOCK_BYREF_CALLER).getBitMask(); + + llvm::Value *flagsVal = llvm::ConstantInt::get(CGF.Int32Ty, flags); + llvm::Value *fn = CGF.CGM.getBlockObjectAssign(); + + llvm::Value *args[] = { destField.getPointer(), srcValue, flagsVal }; + CGF.EmitNounwindRuntimeCall(fn, args); + } + + void emitDispose(CodeGenFunction &CGF, Address field) override { + field = CGF.Builder.CreateBitCast(field, CGF.Int8PtrTy->getPointerTo(0)); + llvm::Value *value = CGF.Builder.CreateLoad(field); + + CGF.BuildBlockRelease(value, Flags | BLOCK_BYREF_CALLER); + } + + void profileImpl(llvm::FoldingSetNodeID &id) const override { + id.AddInteger(Flags.getBitMask()); + } +}; + +/// Emits the copy/dispose helpers for an ARC __block __weak variable. +class ARCWeakByrefHelpers final : public BlockByrefHelpers { +public: + ARCWeakByrefHelpers(CharUnits alignment) : BlockByrefHelpers(alignment) {} + + void emitCopy(CodeGenFunction &CGF, Address destField, + Address srcField) override { + CGF.EmitARCMoveWeak(destField, srcField); + } + + void emitDispose(CodeGenFunction &CGF, Address field) override { + CGF.EmitARCDestroyWeak(field); + } + + void profileImpl(llvm::FoldingSetNodeID &id) const override { + // 0 is distinguishable from all pointers and byref flags + id.AddInteger(0); + } +}; + +/// Emits the copy/dispose helpers for an ARC __block __strong variable +/// that's not of block-pointer type. +class ARCStrongByrefHelpers final : public BlockByrefHelpers { +public: + ARCStrongByrefHelpers(CharUnits alignment) : BlockByrefHelpers(alignment) {} + + void emitCopy(CodeGenFunction &CGF, Address destField, + Address srcField) override { + // Do a "move" by copying the value and then zeroing out the old + // variable. + + llvm::Value *value = CGF.Builder.CreateLoad(srcField); + + llvm::Value *null = + llvm::ConstantPointerNull::get(cast<llvm::PointerType>(value->getType())); + + if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0) { + CGF.Builder.CreateStore(null, destField); + CGF.EmitARCStoreStrongCall(destField, value, /*ignored*/ true); + CGF.EmitARCStoreStrongCall(srcField, null, /*ignored*/ true); + return; + } + CGF.Builder.CreateStore(value, destField); + CGF.Builder.CreateStore(null, srcField); + } + + void emitDispose(CodeGenFunction &CGF, Address field) override { + CGF.EmitARCDestroyStrong(field, ARCImpreciseLifetime); + } + + void profileImpl(llvm::FoldingSetNodeID &id) const override { + // 1 is distinguishable from all pointers and byref flags + id.AddInteger(1); + } +}; + +/// Emits the copy/dispose helpers for an ARC __block __strong +/// variable that's of block-pointer type. +class ARCStrongBlockByrefHelpers final : public BlockByrefHelpers { +public: + ARCStrongBlockByrefHelpers(CharUnits alignment) + : BlockByrefHelpers(alignment) {} + + void emitCopy(CodeGenFunction &CGF, Address destField, + Address srcField) override { + // Do the copy with objc_retainBlock; that's all that + // _Block_object_assign would do anyway, and we'd have to pass the + // right arguments to make sure it doesn't get no-op'ed. + llvm::Value *oldValue = CGF.Builder.CreateLoad(srcField); + llvm::Value *copy = CGF.EmitARCRetainBlock(oldValue, /*mandatory*/ true); + CGF.Builder.CreateStore(copy, destField); + } + + void emitDispose(CodeGenFunction &CGF, Address field) override { + CGF.EmitARCDestroyStrong(field, ARCImpreciseLifetime); + } + + void profileImpl(llvm::FoldingSetNodeID &id) const override { + // 2 is distinguishable from all pointers and byref flags + id.AddInteger(2); + } +}; + +/// Emits the copy/dispose helpers for a __block variable with a +/// nontrivial copy constructor or destructor. +class CXXByrefHelpers final : public BlockByrefHelpers { + QualType VarType; + const Expr *CopyExpr; + +public: + CXXByrefHelpers(CharUnits alignment, QualType type, + const Expr *copyExpr) + : BlockByrefHelpers(alignment), VarType(type), CopyExpr(copyExpr) {} + + bool needsCopy() const override { return CopyExpr != nullptr; } + void emitCopy(CodeGenFunction &CGF, Address destField, + Address srcField) override { + if (!CopyExpr) return; + CGF.EmitSynthesizedCXXCopyCtor(destField, srcField, CopyExpr); + } + + void emitDispose(CodeGenFunction &CGF, Address field) override { + EHScopeStack::stable_iterator cleanupDepth = CGF.EHStack.stable_begin(); + CGF.PushDestructorCleanup(VarType, field); + CGF.PopCleanupBlocks(cleanupDepth); + } + + void profileImpl(llvm::FoldingSetNodeID &id) const override { + id.AddPointer(VarType.getCanonicalType().getAsOpaquePtr()); + } +}; +} // end anonymous namespace + +static llvm::Constant * +generateByrefCopyHelper(CodeGenFunction &CGF, const BlockByrefInfo &byrefInfo, + BlockByrefHelpers &generator) { + ASTContext &Context = CGF.getContext(); + + QualType R = Context.VoidTy; + + FunctionArgList args; + ImplicitParamDecl Dst(CGF.getContext(), Context.VoidPtrTy, + ImplicitParamDecl::Other); + args.push_back(&Dst); + + ImplicitParamDecl Src(CGF.getContext(), Context.VoidPtrTy, + ImplicitParamDecl::Other); + args.push_back(&Src); + + const CGFunctionInfo &FI = + CGF.CGM.getTypes().arrangeBuiltinFunctionDeclaration(R, args); + + llvm::FunctionType *LTy = CGF.CGM.getTypes().GetFunctionType(FI); + + // FIXME: We'd like to put these into a mergable by content, with + // internal linkage. + llvm::Function *Fn = + llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, + "__Block_byref_object_copy_", &CGF.CGM.getModule()); + + IdentifierInfo *II + = &Context.Idents.get("__Block_byref_object_copy_"); + + FunctionDecl *FD = FunctionDecl::Create(Context, + Context.getTranslationUnitDecl(), + SourceLocation(), + SourceLocation(), II, R, nullptr, + SC_Static, + false, false); + + CGF.CGM.SetInternalFunctionAttributes(nullptr, Fn, FI); + + CGF.StartFunction(FD, R, Fn, FI, args); + + if (generator.needsCopy()) { + llvm::Type *byrefPtrType = byrefInfo.Type->getPointerTo(0); + + // dst->x + Address destField = CGF.GetAddrOfLocalVar(&Dst); + destField = Address(CGF.Builder.CreateLoad(destField), + byrefInfo.ByrefAlignment); + destField = CGF.Builder.CreateBitCast(destField, byrefPtrType); + destField = CGF.emitBlockByrefAddress(destField, byrefInfo, false, + "dest-object"); + + // src->x + Address srcField = CGF.GetAddrOfLocalVar(&Src); + srcField = Address(CGF.Builder.CreateLoad(srcField), + byrefInfo.ByrefAlignment); + srcField = CGF.Builder.CreateBitCast(srcField, byrefPtrType); + srcField = CGF.emitBlockByrefAddress(srcField, byrefInfo, false, + "src-object"); + + generator.emitCopy(CGF, destField, srcField); + } + + CGF.FinishFunction(); + + return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy); +} + +/// Build the copy helper for a __block variable. +static llvm::Constant *buildByrefCopyHelper(CodeGenModule &CGM, + const BlockByrefInfo &byrefInfo, + BlockByrefHelpers &generator) { + CodeGenFunction CGF(CGM); + return generateByrefCopyHelper(CGF, byrefInfo, generator); +} + +/// Generate code for a __block variable's dispose helper. +static llvm::Constant * +generateByrefDisposeHelper(CodeGenFunction &CGF, + const BlockByrefInfo &byrefInfo, + BlockByrefHelpers &generator) { + ASTContext &Context = CGF.getContext(); + QualType R = Context.VoidTy; + + FunctionArgList args; + ImplicitParamDecl Src(CGF.getContext(), Context.VoidPtrTy, + ImplicitParamDecl::Other); + args.push_back(&Src); + + const CGFunctionInfo &FI = + CGF.CGM.getTypes().arrangeBuiltinFunctionDeclaration(R, args); + + llvm::FunctionType *LTy = CGF.CGM.getTypes().GetFunctionType(FI); + + // FIXME: We'd like to put these into a mergable by content, with + // internal linkage. + llvm::Function *Fn = + llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage, + "__Block_byref_object_dispose_", + &CGF.CGM.getModule()); + + IdentifierInfo *II + = &Context.Idents.get("__Block_byref_object_dispose_"); + + FunctionDecl *FD = FunctionDecl::Create(Context, + Context.getTranslationUnitDecl(), + SourceLocation(), + SourceLocation(), II, R, nullptr, + SC_Static, + false, false); + + CGF.CGM.SetInternalFunctionAttributes(nullptr, Fn, FI); + + CGF.StartFunction(FD, R, Fn, FI, args); + + if (generator.needsDispose()) { + Address addr = CGF.GetAddrOfLocalVar(&Src); + addr = Address(CGF.Builder.CreateLoad(addr), byrefInfo.ByrefAlignment); + auto byrefPtrType = byrefInfo.Type->getPointerTo(0); + addr = CGF.Builder.CreateBitCast(addr, byrefPtrType); + addr = CGF.emitBlockByrefAddress(addr, byrefInfo, false, "object"); + + generator.emitDispose(CGF, addr); + } + + CGF.FinishFunction(); + + return llvm::ConstantExpr::getBitCast(Fn, CGF.Int8PtrTy); +} + +/// Build the dispose helper for a __block variable. +static llvm::Constant *buildByrefDisposeHelper(CodeGenModule &CGM, + const BlockByrefInfo &byrefInfo, + BlockByrefHelpers &generator) { + CodeGenFunction CGF(CGM); + return generateByrefDisposeHelper(CGF, byrefInfo, generator); +} + +/// Lazily build the copy and dispose helpers for a __block variable +/// with the given information. +template <class T> +static T *buildByrefHelpers(CodeGenModule &CGM, const BlockByrefInfo &byrefInfo, + T &&generator) { + llvm::FoldingSetNodeID id; + generator.Profile(id); + + void *insertPos; + BlockByrefHelpers *node + = CGM.ByrefHelpersCache.FindNodeOrInsertPos(id, insertPos); + if (node) return static_cast<T*>(node); + + generator.CopyHelper = buildByrefCopyHelper(CGM, byrefInfo, generator); + generator.DisposeHelper = buildByrefDisposeHelper(CGM, byrefInfo, generator); + + T *copy = new (CGM.getContext()) T(std::forward<T>(generator)); + CGM.ByrefHelpersCache.InsertNode(copy, insertPos); + return copy; +} + +/// Build the copy and dispose helpers for the given __block variable +/// emission. Places the helpers in the global cache. Returns null +/// if no helpers are required. +BlockByrefHelpers * +CodeGenFunction::buildByrefHelpers(llvm::StructType &byrefType, + const AutoVarEmission &emission) { + const VarDecl &var = *emission.Variable; + QualType type = var.getType(); + + auto &byrefInfo = getBlockByrefInfo(&var); + + // The alignment we care about for the purposes of uniquing byref + // helpers is the alignment of the actual byref value field. + CharUnits valueAlignment = + byrefInfo.ByrefAlignment.alignmentAtOffset(byrefInfo.FieldOffset); + + if (const CXXRecordDecl *record = type->getAsCXXRecordDecl()) { + const Expr *copyExpr = CGM.getContext().getBlockVarCopyInits(&var); + if (!copyExpr && record->hasTrivialDestructor()) return nullptr; + + return ::buildByrefHelpers( + CGM, byrefInfo, CXXByrefHelpers(valueAlignment, type, copyExpr)); + } + + // Otherwise, if we don't have a retainable type, there's nothing to do. + // that the runtime does extra copies. + if (!type->isObjCRetainableType()) return nullptr; + + Qualifiers qs = type.getQualifiers(); + + // If we have lifetime, that dominates. + if (Qualifiers::ObjCLifetime lifetime = qs.getObjCLifetime()) { + switch (lifetime) { + case Qualifiers::OCL_None: llvm_unreachable("impossible"); + + // These are just bits as far as the runtime is concerned. + case Qualifiers::OCL_ExplicitNone: + case Qualifiers::OCL_Autoreleasing: + return nullptr; + + // Tell the runtime that this is ARC __weak, called by the + // byref routines. + case Qualifiers::OCL_Weak: + return ::buildByrefHelpers(CGM, byrefInfo, + ARCWeakByrefHelpers(valueAlignment)); + + // ARC __strong __block variables need to be retained. + case Qualifiers::OCL_Strong: + // Block pointers need to be copied, and there's no direct + // transfer possible. + if (type->isBlockPointerType()) { + return ::buildByrefHelpers(CGM, byrefInfo, + ARCStrongBlockByrefHelpers(valueAlignment)); + + // Otherwise, we transfer ownership of the retain from the stack + // to the heap. + } else { + return ::buildByrefHelpers(CGM, byrefInfo, + ARCStrongByrefHelpers(valueAlignment)); + } + } + llvm_unreachable("fell out of lifetime switch!"); + } + + BlockFieldFlags flags; + if (type->isBlockPointerType()) { + flags |= BLOCK_FIELD_IS_BLOCK; + } else if (CGM.getContext().isObjCNSObjectType(type) || + type->isObjCObjectPointerType()) { + flags |= BLOCK_FIELD_IS_OBJECT; + } else { + return nullptr; + } + + if (type.isObjCGCWeak()) + flags |= BLOCK_FIELD_IS_WEAK; + + return ::buildByrefHelpers(CGM, byrefInfo, + ObjectByrefHelpers(valueAlignment, flags)); +} + +Address CodeGenFunction::emitBlockByrefAddress(Address baseAddr, + const VarDecl *var, + bool followForward) { + auto &info = getBlockByrefInfo(var); + return emitBlockByrefAddress(baseAddr, info, followForward, var->getName()); +} + +Address CodeGenFunction::emitBlockByrefAddress(Address baseAddr, + const BlockByrefInfo &info, + bool followForward, + const llvm::Twine &name) { + // Chase the forwarding address if requested. + if (followForward) { + Address forwardingAddr = + Builder.CreateStructGEP(baseAddr, 1, getPointerSize(), "forwarding"); + baseAddr = Address(Builder.CreateLoad(forwardingAddr), info.ByrefAlignment); + } + + return Builder.CreateStructGEP(baseAddr, info.FieldIndex, + info.FieldOffset, name); +} + +/// BuildByrefInfo - This routine changes a __block variable declared as T x +/// into: +/// +/// struct { +/// void *__isa; +/// void *__forwarding; +/// int32_t __flags; +/// int32_t __size; +/// void *__copy_helper; // only if needed +/// void *__destroy_helper; // only if needed +/// void *__byref_variable_layout;// only if needed +/// char padding[X]; // only if needed +/// T x; +/// } x +/// +const BlockByrefInfo &CodeGenFunction::getBlockByrefInfo(const VarDecl *D) { + auto it = BlockByrefInfos.find(D); + if (it != BlockByrefInfos.end()) + return it->second; + + llvm::StructType *byrefType = + llvm::StructType::create(getLLVMContext(), + "struct.__block_byref_" + D->getNameAsString()); + + QualType Ty = D->getType(); + + CharUnits size; + SmallVector<llvm::Type *, 8> types; + + // void *__isa; + types.push_back(Int8PtrTy); + size += getPointerSize(); + + // void *__forwarding; + types.push_back(llvm::PointerType::getUnqual(byrefType)); + size += getPointerSize(); + + // int32_t __flags; + types.push_back(Int32Ty); + size += CharUnits::fromQuantity(4); + + // int32_t __size; + types.push_back(Int32Ty); + size += CharUnits::fromQuantity(4); + + // Note that this must match *exactly* the logic in buildByrefHelpers. + bool hasCopyAndDispose = getContext().BlockRequiresCopying(Ty, D); + if (hasCopyAndDispose) { + /// void *__copy_helper; + types.push_back(Int8PtrTy); + size += getPointerSize(); + + /// void *__destroy_helper; + types.push_back(Int8PtrTy); + size += getPointerSize(); + } + + bool HasByrefExtendedLayout = false; + Qualifiers::ObjCLifetime Lifetime; + if (getContext().getByrefLifetime(Ty, Lifetime, HasByrefExtendedLayout) && + HasByrefExtendedLayout) { + /// void *__byref_variable_layout; + types.push_back(Int8PtrTy); + size += CharUnits::fromQuantity(PointerSizeInBytes); + } + + // T x; + llvm::Type *varTy = ConvertTypeForMem(Ty); + + bool packed = false; + CharUnits varAlign = getContext().getDeclAlign(D); + CharUnits varOffset = size.alignTo(varAlign); + + // We may have to insert padding. + if (varOffset != size) { + llvm::Type *paddingTy = + llvm::ArrayType::get(Int8Ty, (varOffset - size).getQuantity()); + + types.push_back(paddingTy); + size = varOffset; + + // Conversely, we might have to prevent LLVM from inserting padding. + } else if (CGM.getDataLayout().getABITypeAlignment(varTy) + > varAlign.getQuantity()) { + packed = true; + } + types.push_back(varTy); + + byrefType->setBody(types, packed); + + BlockByrefInfo info; + info.Type = byrefType; + info.FieldIndex = types.size() - 1; + info.FieldOffset = varOffset; + info.ByrefAlignment = std::max(varAlign, getPointerAlign()); + + auto pair = BlockByrefInfos.insert({D, info}); + assert(pair.second && "info was inserted recursively?"); + return pair.first->second; +} + +/// Initialize the structural components of a __block variable, i.e. +/// everything but the actual object. +void CodeGenFunction::emitByrefStructureInit(const AutoVarEmission &emission) { + // Find the address of the local. + Address addr = emission.Addr; + + // That's an alloca of the byref structure type. + llvm::StructType *byrefType = cast<llvm::StructType>( + cast<llvm::PointerType>(addr.getPointer()->getType())->getElementType()); + + unsigned nextHeaderIndex = 0; + CharUnits nextHeaderOffset; + auto storeHeaderField = [&](llvm::Value *value, CharUnits fieldSize, + const Twine &name) { + auto fieldAddr = Builder.CreateStructGEP(addr, nextHeaderIndex, + nextHeaderOffset, name); + Builder.CreateStore(value, fieldAddr); + + nextHeaderIndex++; + nextHeaderOffset += fieldSize; + }; + + // Build the byref helpers if necessary. This is null if we don't need any. + BlockByrefHelpers *helpers = buildByrefHelpers(*byrefType, emission); + + const VarDecl &D = *emission.Variable; + QualType type = D.getType(); + + bool HasByrefExtendedLayout; + Qualifiers::ObjCLifetime ByrefLifetime; + bool ByRefHasLifetime = + getContext().getByrefLifetime(type, ByrefLifetime, HasByrefExtendedLayout); + + llvm::Value *V; + + // Initialize the 'isa', which is just 0 or 1. + int isa = 0; + if (type.isObjCGCWeak()) + isa = 1; + V = Builder.CreateIntToPtr(Builder.getInt32(isa), Int8PtrTy, "isa"); + storeHeaderField(V, getPointerSize(), "byref.isa"); + + // Store the address of the variable into its own forwarding pointer. + storeHeaderField(addr.getPointer(), getPointerSize(), "byref.forwarding"); + + // Blocks ABI: + // c) the flags field is set to either 0 if no helper functions are + // needed or BLOCK_BYREF_HAS_COPY_DISPOSE if they are, + BlockFlags flags; + if (helpers) flags |= BLOCK_BYREF_HAS_COPY_DISPOSE; + if (ByRefHasLifetime) { + if (HasByrefExtendedLayout) flags |= BLOCK_BYREF_LAYOUT_EXTENDED; + else switch (ByrefLifetime) { + case Qualifiers::OCL_Strong: + flags |= BLOCK_BYREF_LAYOUT_STRONG; + break; + case Qualifiers::OCL_Weak: + flags |= BLOCK_BYREF_LAYOUT_WEAK; + break; + case Qualifiers::OCL_ExplicitNone: + flags |= BLOCK_BYREF_LAYOUT_UNRETAINED; + break; + case Qualifiers::OCL_None: + if (!type->isObjCObjectPointerType() && !type->isBlockPointerType()) + flags |= BLOCK_BYREF_LAYOUT_NON_OBJECT; + break; + default: + break; + } + if (CGM.getLangOpts().ObjCGCBitmapPrint) { + printf("\n Inline flag for BYREF variable layout (%d):", flags.getBitMask()); + if (flags & BLOCK_BYREF_HAS_COPY_DISPOSE) + printf(" BLOCK_BYREF_HAS_COPY_DISPOSE"); + if (flags & BLOCK_BYREF_LAYOUT_MASK) { + BlockFlags ThisFlag(flags.getBitMask() & BLOCK_BYREF_LAYOUT_MASK); + if (ThisFlag == BLOCK_BYREF_LAYOUT_EXTENDED) + printf(" BLOCK_BYREF_LAYOUT_EXTENDED"); + if (ThisFlag == BLOCK_BYREF_LAYOUT_STRONG) + printf(" BLOCK_BYREF_LAYOUT_STRONG"); + if (ThisFlag == BLOCK_BYREF_LAYOUT_WEAK) + printf(" BLOCK_BYREF_LAYOUT_WEAK"); + if (ThisFlag == BLOCK_BYREF_LAYOUT_UNRETAINED) + printf(" BLOCK_BYREF_LAYOUT_UNRETAINED"); + if (ThisFlag == BLOCK_BYREF_LAYOUT_NON_OBJECT) + printf(" BLOCK_BYREF_LAYOUT_NON_OBJECT"); + } + printf("\n"); + } + } + storeHeaderField(llvm::ConstantInt::get(IntTy, flags.getBitMask()), + getIntSize(), "byref.flags"); + + CharUnits byrefSize = CGM.GetTargetTypeStoreSize(byrefType); + V = llvm::ConstantInt::get(IntTy, byrefSize.getQuantity()); + storeHeaderField(V, getIntSize(), "byref.size"); + + if (helpers) { + storeHeaderField(helpers->CopyHelper, getPointerSize(), + "byref.copyHelper"); + storeHeaderField(helpers->DisposeHelper, getPointerSize(), + "byref.disposeHelper"); + } + + if (ByRefHasLifetime && HasByrefExtendedLayout) { + auto layoutInfo = CGM.getObjCRuntime().BuildByrefLayout(CGM, type); + storeHeaderField(layoutInfo, getPointerSize(), "byref.layout"); + } +} + +void CodeGenFunction::BuildBlockRelease(llvm::Value *V, BlockFieldFlags flags) { + llvm::Value *F = CGM.getBlockObjectDispose(); + llvm::Value *args[] = { + Builder.CreateBitCast(V, Int8PtrTy), + llvm::ConstantInt::get(Int32Ty, flags.getBitMask()) + }; + EmitNounwindRuntimeCall(F, args); // FIXME: throwing destructors? +} + +namespace { + /// Release a __block variable. + struct CallBlockRelease final : EHScopeStack::Cleanup { + llvm::Value *Addr; + CallBlockRelease(llvm::Value *Addr) : Addr(Addr) {} + + void Emit(CodeGenFunction &CGF, Flags flags) override { + // Should we be passing FIELD_IS_WEAK here? + CGF.BuildBlockRelease(Addr, BLOCK_FIELD_IS_BYREF); + } + }; +} // end anonymous namespace + +/// Enter a cleanup to destroy a __block variable. Note that this +/// cleanup should be a no-op if the variable hasn't left the stack +/// yet; if a cleanup is required for the variable itself, that needs +/// to be done externally. +void CodeGenFunction::enterByrefCleanup(const AutoVarEmission &emission) { + // We don't enter this cleanup if we're in pure-GC mode. + if (CGM.getLangOpts().getGC() == LangOptions::GCOnly) + return; + + EHStack.pushCleanup<CallBlockRelease>(NormalAndEHCleanup, + emission.Addr.getPointer()); +} + +/// Adjust the declaration of something from the blocks API. +static void configureBlocksRuntimeObject(CodeGenModule &CGM, + llvm::Constant *C) { + auto *GV = cast<llvm::GlobalValue>(C->stripPointerCasts()); + + if (CGM.getTarget().getTriple().isOSBinFormatCOFF()) { + IdentifierInfo &II = CGM.getContext().Idents.get(C->getName()); + TranslationUnitDecl *TUDecl = CGM.getContext().getTranslationUnitDecl(); + DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl); + + assert((isa<llvm::Function>(C->stripPointerCasts()) || + isa<llvm::GlobalVariable>(C->stripPointerCasts())) && + "expected Function or GlobalVariable"); + + const NamedDecl *ND = nullptr; + for (const auto &Result : DC->lookup(&II)) + if ((ND = dyn_cast<FunctionDecl>(Result)) || + (ND = dyn_cast<VarDecl>(Result))) + break; + + // TODO: support static blocks runtime + if (GV->isDeclaration() && (!ND || !ND->hasAttr<DLLExportAttr>())) { + GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass); + GV->setLinkage(llvm::GlobalValue::ExternalLinkage); + } else { + GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass); + GV->setLinkage(llvm::GlobalValue::ExternalLinkage); + } + } + + if (!CGM.getLangOpts().BlocksRuntimeOptional) + return; + + if (GV->isDeclaration() && GV->hasExternalLinkage()) + GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage); +} + +llvm::Constant *CodeGenModule::getBlockObjectDispose() { + if (BlockObjectDispose) + return BlockObjectDispose; + + llvm::Type *args[] = { Int8PtrTy, Int32Ty }; + llvm::FunctionType *fty + = llvm::FunctionType::get(VoidTy, args, false); + BlockObjectDispose = CreateRuntimeFunction(fty, "_Block_object_dispose"); + configureBlocksRuntimeObject(*this, BlockObjectDispose); + return BlockObjectDispose; +} + +llvm::Constant *CodeGenModule::getBlockObjectAssign() { + if (BlockObjectAssign) + return BlockObjectAssign; + + llvm::Type *args[] = { Int8PtrTy, Int8PtrTy, Int32Ty }; + llvm::FunctionType *fty + = llvm::FunctionType::get(VoidTy, args, false); + BlockObjectAssign = CreateRuntimeFunction(fty, "_Block_object_assign"); + configureBlocksRuntimeObject(*this, BlockObjectAssign); + return BlockObjectAssign; +} + +llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() { + if (NSConcreteGlobalBlock) + return NSConcreteGlobalBlock; + + NSConcreteGlobalBlock = GetOrCreateLLVMGlobal("_NSConcreteGlobalBlock", + Int8PtrTy->getPointerTo(), + nullptr); + configureBlocksRuntimeObject(*this, NSConcreteGlobalBlock); + return NSConcreteGlobalBlock; +} + +llvm::Constant *CodeGenModule::getNSConcreteStackBlock() { + if (NSConcreteStackBlock) + return NSConcreteStackBlock; + + NSConcreteStackBlock = GetOrCreateLLVMGlobal("_NSConcreteStackBlock", + Int8PtrTy->getPointerTo(), + nullptr); + configureBlocksRuntimeObject(*this, NSConcreteStackBlock); + return NSConcreteStackBlock; +} |