| //===--- CGBlocks.cpp - Emit LLVM Code for declarations ---------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This contains code to emit blocks. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "CGBlocks.h" |
| #include "CGCXXABI.h" |
| #include "CGDebugInfo.h" |
| #include "CGObjCRuntime.h" |
| #include "CGOpenCLRuntime.h" |
| #include "CodeGenFunction.h" |
| #include "CodeGenModule.h" |
| #include "ConstantEmitter.h" |
| #include "TargetInfo.h" |
| #include "clang/AST/Attr.h" |
| #include "clang/AST/DeclObjC.h" |
| #include "clang/CodeGen/ConstantInitBuilder.h" |
| #include "llvm/ADT/SmallSet.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/Support/ScopedPrinter.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), |
| CapturesNonExternalType(false), LocalAddress(Address::invalid()), |
| StructureType(nullptr), Block(block) { |
| |
| // 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); |
| } |
| |
| 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, |
| NonTrivialCStruct, |
| 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 CopyKind, DisposeKind; |
| BlockFieldFlags CopyFlags, DisposeFlags; |
| const BlockDecl::Capture *CI; |
| const CGBlockInfo::Capture *Capture; |
| |
| BlockCaptureManagedEntity(BlockCaptureEntityKind CopyType, |
| BlockCaptureEntityKind DisposeType, |
| BlockFieldFlags CopyFlags, |
| BlockFieldFlags DisposeFlags, |
| const BlockDecl::Capture &CI, |
| const CGBlockInfo::Capture &Capture) |
| : CopyKind(CopyType), DisposeKind(DisposeType), CopyFlags(CopyFlags), |
| DisposeFlags(DisposeFlags), CI(&CI), Capture(&Capture) {} |
| |
| bool operator<(const BlockCaptureManagedEntity &Other) const { |
| return Capture->getOffset() < Other.Capture->getOffset(); |
| } |
| }; |
| |
| enum class CaptureStrKind { |
| // String for the copy helper. |
| CopyHelper, |
| // String for the dispose helper. |
| DisposeHelper, |
| // Merge the strings for the copy helper and dispose helper. |
| Merged |
| }; |
| |
| } // end anonymous namespace |
| |
| static void findBlockCapturedManagedEntities( |
| const CGBlockInfo &BlockInfo, const LangOptions &LangOpts, |
| SmallVectorImpl<BlockCaptureManagedEntity> &ManagedCaptures); |
| |
| static std::string getBlockCaptureStr(const BlockCaptureManagedEntity &E, |
| CaptureStrKind StrKind, |
| CharUnits BlockAlignment, |
| CodeGenModule &CGM); |
| |
| static std::string getBlockDescriptorName(const CGBlockInfo &BlockInfo, |
| CodeGenModule &CGM) { |
| std::string Name = "__block_descriptor_"; |
| Name += llvm::to_string(BlockInfo.BlockSize.getQuantity()) + "_"; |
| |
| if (BlockInfo.needsCopyDisposeHelpers()) { |
| if (CGM.getLangOpts().Exceptions) |
| Name += "e"; |
| if (CGM.getCodeGenOpts().ObjCAutoRefCountExceptions) |
| Name += "a"; |
| Name += llvm::to_string(BlockInfo.BlockAlign.getQuantity()) + "_"; |
| |
| SmallVector<BlockCaptureManagedEntity, 4> ManagedCaptures; |
| findBlockCapturedManagedEntities(BlockInfo, CGM.getContext().getLangOpts(), |
| ManagedCaptures); |
| |
| for (const BlockCaptureManagedEntity &E : ManagedCaptures) { |
| Name += llvm::to_string(E.Capture->getOffset().getQuantity()); |
| |
| if (E.CopyKind == E.DisposeKind) { |
| // If CopyKind and DisposeKind are the same, merge the capture |
| // information. |
| assert(E.CopyKind != BlockCaptureEntityKind::None && |
| "shouldn't see BlockCaptureManagedEntity that is None"); |
| Name += getBlockCaptureStr(E, CaptureStrKind::Merged, |
| BlockInfo.BlockAlign, CGM); |
| } else { |
| // If CopyKind and DisposeKind are not the same, which can happen when |
| // either Kind is None or the captured object is a __strong block, |
| // concatenate the copy and dispose strings. |
| Name += getBlockCaptureStr(E, CaptureStrKind::CopyHelper, |
| BlockInfo.BlockAlign, CGM); |
| Name += getBlockCaptureStr(E, CaptureStrKind::DisposeHelper, |
| BlockInfo.BlockAlign, CGM); |
| } |
| } |
| Name += "_"; |
| } |
| |
| std::string TypeAtEncoding = |
| CGM.getContext().getObjCEncodingForBlock(BlockInfo.getBlockExpr()); |
| /// Replace occurrences of '@' with '\1'. '@' is reserved on ELF platforms as |
| /// a separator between symbol name and symbol version. |
| std::replace(TypeAtEncoding.begin(), TypeAtEncoding.end(), '@', '\1'); |
| Name += "e" + llvm::to_string(TypeAtEncoding.size()) + "_" + TypeAtEncoding; |
| Name += "l" + CGM.getObjCRuntime().getRCBlockLayoutStr(CGM, BlockInfo); |
| return Name; |
| } |
| |
| /// 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 optionally 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; // optional 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; |
| |
| std::string descName; |
| |
| // If an equivalent block descriptor global variable exists, return it. |
| if (C.getLangOpts().ObjC && |
| CGM.getLangOpts().getGC() == LangOptions::NonGC) { |
| descName = getBlockDescriptorName(blockInfo, CGM); |
| if (llvm::GlobalValue *desc = CGM.getModule().getNamedValue(descName)) |
| return llvm::ConstantExpr::getBitCast(desc, |
| CGM.getBlockDescriptorType()); |
| } |
| |
| // If there isn't an equivalent block descriptor global variable, create a new |
| // one. |
| 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. |
| bool hasInternalHelper = false; |
| if (blockInfo.needsCopyDisposeHelpers()) { |
| // copy_func_helper_decl |
| llvm::Constant *copyHelper = buildCopyHelper(CGM, blockInfo); |
| elements.add(copyHelper); |
| |
| // destroy_func_decl |
| llvm::Constant *disposeHelper = buildDisposeHelper(CGM, blockInfo); |
| elements.add(disposeHelper); |
| |
| if (cast<llvm::Function>(copyHelper->getOperand(0))->hasInternalLinkage() || |
| cast<llvm::Function>(disposeHelper->getOperand(0)) |
| ->hasInternalLinkage()) |
| hasInternalHelper = true; |
| } |
| |
| // 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().ObjC) { |
| 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::GlobalValue::LinkageTypes linkage; |
| if (descName.empty()) { |
| linkage = llvm::GlobalValue::InternalLinkage; |
| descName = "__block_descriptor_tmp"; |
| } else if (hasInternalHelper) { |
| // If either the copy helper or the dispose helper has internal linkage, |
| // the block descriptor must have internal linkage too. |
| linkage = llvm::GlobalValue::InternalLinkage; |
| } else { |
| linkage = llvm::GlobalValue::LinkOnceODRLinkage; |
| } |
| |
| llvm::GlobalVariable *global = |
| elements.finishAndCreateGlobal(descName, CGM.getPointerAlign(), |
| /*constant*/ true, linkage, AddrSpace); |
| |
| if (linkage == llvm::GlobalValue::LinkOnceODRLinkage) { |
| if (CGM.supportsCOMDAT()) |
| global->setComdat(CGM.getModule().getOrInsertComdat(descName)); |
| global->setVisibility(llvm::GlobalValue::HiddenVisibility); |
| global->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global); |
| } |
| |
| 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. |
| /// 23. BLOCK_IS_NOESCAPE - indicates that the block is non-escaping |
| /// 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 ConstantEmitter(CGM, CGF).tryEmitAbstractForInitializer(*var); |
| } |
| |
| /// 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) { |
| |
| assert(elementTypes.empty()); |
| if (CGM.getLangOpts().OpenCL) { |
| // The header is basically 'struct { int; int; generic void *; |
| // custom_fields; }'. Assert that struct is packed. |
| auto GenericAS = |
| CGM.getContext().getTargetAddressSpace(LangAS::opencl_generic); |
| auto GenPtrAlign = |
| CharUnits::fromQuantity(CGM.getTarget().getPointerAlign(GenericAS) / 8); |
| auto GenPtrSize = |
| CharUnits::fromQuantity(CGM.getTarget().getPointerWidth(GenericAS) / 8); |
| assert(CGM.getIntSize() <= GenPtrSize); |
| assert(CGM.getIntAlign() <= GenPtrAlign); |
| assert((2 * CGM.getIntSize()).isMultipleOf(GenPtrAlign)); |
| elementTypes.push_back(CGM.IntTy); /* total size */ |
| elementTypes.push_back(CGM.IntTy); /* align */ |
| elementTypes.push_back( |
| CGM.getOpenCLRuntime() |
| .getGenericVoidPointerType()); /* invoke function */ |
| unsigned Offset = |
| 2 * CGM.getIntSize().getQuantity() + GenPtrSize.getQuantity(); |
| unsigned BlockAlign = GenPtrAlign.getQuantity(); |
| if (auto *Helper = |
| CGM.getTargetCodeGenInfo().getTargetOpenCLBlockHelper()) { |
| for (auto I : Helper->getCustomFieldTypes()) /* custom fields */ { |
| // TargetOpenCLBlockHelp needs to make sure the struct is packed. |
| // If necessary, add padding fields to the custom fields. |
| unsigned Align = CGM.getDataLayout().getABITypeAlignment(I); |
| if (BlockAlign < Align) |
| BlockAlign = Align; |
| assert(Offset % Align == 0); |
| Offset += CGM.getDataLayout().getTypeAllocSize(I); |
| elementTypes.push_back(I); |
| } |
| } |
| info.BlockAlign = CharUnits::fromQuantity(BlockAlign); |
| info.BlockSize = CharUnits::fromQuantity(Offset); |
| } else { |
| // The header is basically 'struct { void *; int; int; void *; void *; }'. |
| // Assert that the 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(); |
| 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(); |
| // If the captured variable is a non-escaping __block variable, the field |
| // type is the reference type. If the variable is a __block variable that |
| // already has a reference type, the field type is the variable's type. |
| return VD->isNonEscapingByref() ? |
| CGF.getContext().getLValueReferenceType(VD->getType()) : 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); |
| bool hasNonConstantCustomFields = false; |
| if (auto *OpenCLHelper = |
| CGM.getTargetCodeGenInfo().getTargetOpenCLBlockHelper()) |
| hasNonConstantCustomFields = |
| !OpenCLHelper->areAllCustomFieldValuesConstant(info); |
| if (!block->hasCaptures() && !hasNonConstantCustomFields) { |
| info.StructureType = |
| llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true); |
| info.CanBeGlobal = true; |
| return; |
| } |
| else if (C.getLangOpts().ObjC && |
| 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(); |
| |
| // 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.isEscapingByref()) { |
| // 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); |
| |
| // Since a __block variable cannot be captured by lambdas, its type and |
| // the capture field type should always match. |
| assert(getCaptureFieldType(*CGF, CI) == variable->getType() && |
| "capture type differs from the variable type"); |
| 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; |
| } |
| |
| QualType VT = getCaptureFieldType(*CGF, CI); |
| |
| // If we have a lifetime qualifier, honor it for capture purposes. |
| // That includes *not* copying it if it's __unsafe_unretained. |
| Qualifiers::ObjCLifetime lifetime = VT.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 (VT->isObjCRetainableType()) { |
| // But honor the inert __unsafe_unretained qualifier, which doesn't |
| // actually make it into the type system. |
| if (VT->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; |
| if (!VT->getAsCXXRecordDecl()->isExternallyVisible()) |
| info.CapturesNonExternalType = true; |
| |
| // So do C structs that require non-trivial copy construction or |
| // destruction. |
| } else if (VT.isNonTrivialToPrimitiveCopy() == QualType::PCK_Struct || |
| VT.isDestructedType() == QualType::DK_nontrivial_c_struct) { |
| info.NeedsCopyDispose = true; |
| |
| // And so do types with destructors. |
| } else if (CGM.getLangOpts().CPlusPlus) { |
| if (const CXXRecordDecl *record = VT->getAsCXXRecordDecl()) { |
| if (!record->hasTrivialDestructor()) { |
| info.HasCXXObject = true; |
| info.NeedsCopyDispose = true; |
| if (!record->isExternallyVisible()) |
| info.CapturesNonExternalType = true; |
| } |
| } |
| } |
| |
| 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. |
| llvm::stable_sort(layout); |
| |
| // 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); |
| } |
| |
| /// 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()) |
| // The block literal is emitted as a global variable, and the block invoke |
| // function has to be extracted from its initializer. |
| if (llvm::Constant *Block = CGM.getAddrOfGlobalBlockIfEmitted(blockExpr)) |
| return Block; |
| |
| CGBlockInfo blockInfo(blockExpr->getBlockDecl(), CurFn->getName()); |
| computeBlockInfo(CGM, this, blockInfo); |
| blockInfo.BlockExpression = blockExpr; |
| if (!blockInfo.CanBeGlobal) |
| blockInfo.LocalAddress = CreateTempAlloca(blockInfo.StructureType, |
| blockInfo.BlockAlign, "block"); |
| return EmitBlockLiteral(blockInfo); |
| } |
| |
| llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo) { |
| bool IsOpenCL = CGM.getContext().getLangOpts().OpenCL; |
| auto GenVoidPtrTy = |
| IsOpenCL ? CGM.getOpenCLRuntime().getGenericVoidPointerType() : VoidPtrTy; |
| LangAS GenVoidPtrAddr = IsOpenCL ? LangAS::opencl_generic : LangAS::Default; |
| auto GenVoidPtrSize = CharUnits::fromQuantity( |
| CGM.getTarget().getPointerWidth( |
| CGM.getContext().getTargetAddressSpace(GenVoidPtrAddr)) / |
| 8); |
| // Using the computed layout, generate the actual block function. |
| bool isLambdaConv = blockInfo.getBlockDecl()->isConversionFromLambda(); |
| CodeGenFunction BlockCGF{CGM, true}; |
| BlockCGF.SanOpts = SanOpts; |
| auto *InvokeFn = BlockCGF.GenerateBlockFunction( |
| CurGD, blockInfo, LocalDeclMap, isLambdaConv, blockInfo.CanBeGlobal); |
| auto *blockFn = llvm::ConstantExpr::getPointerCast(InvokeFn, GenVoidPtrTy); |
| |
| // If there is nothing to capture, we can emit this as a global block. |
| if (blockInfo.CanBeGlobal) |
| return CGM.getAddrOfGlobalBlockIfEmitted(blockInfo.BlockExpression); |
| |
| // Otherwise, we have to emit this as a local block. |
| |
| Address blockAddr = blockInfo.LocalAddress; |
| assert(blockAddr.isValid() && "block has no address!"); |
| |
| llvm::Constant *isa; |
| llvm::Constant *descriptor; |
| BlockFlags flags; |
| if (!IsOpenCL) { |
| // If the block is non-escaping, set field 'isa 'to NSConcreteGlobalBlock |
| // and set the BLOCK_IS_GLOBAL bit of field 'flags'. Copying a non-escaping |
| // block just returns the original block and releasing it is a no-op. |
| llvm::Constant *blockISA = blockInfo.getBlockDecl()->doesNotEscape() |
| ? CGM.getNSConcreteGlobalBlock() |
| : CGM.getNSConcreteStackBlock(); |
| isa = llvm::ConstantExpr::getBitCast(blockISA, VoidPtrTy); |
| |
| // Build the block descriptor. |
| descriptor = buildBlockDescriptor(CGM, blockInfo); |
| |
| // Compute the initial on-stack block flags. |
| flags = BLOCK_HAS_SIGNATURE; |
| if (blockInfo.HasCapturedVariableLayout) |
| flags |= BLOCK_HAS_EXTENDED_LAYOUT; |
| if (blockInfo.needsCopyDisposeHelpers()) |
| flags |= BLOCK_HAS_COPY_DISPOSE; |
| if (blockInfo.HasCXXObject) |
| flags |= BLOCK_HAS_CXX_OBJ; |
| if (blockInfo.UsesStret) |
| flags |= BLOCK_USE_STRET; |
| if (blockInfo.getBlockDecl()->doesNotEscape()) |
| flags |= BLOCK_IS_NOESCAPE | BLOCK_IS_GLOBAL; |
| } |
| |
| auto projectField = [&](unsigned index, const Twine &name) -> Address { |
| return Builder.CreateStructGEP(blockAddr, index, name); |
| }; |
| auto storeField = [&](llvm::Value *value, unsigned index, const Twine &name) { |
| Builder.CreateStore(value, projectField(index, 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, name); |
| offset += size; |
| index++; |
| }; |
| |
| if (!IsOpenCL) { |
| addHeaderField(isa, getPointerSize(), "block.isa"); |
| addHeaderField(llvm::ConstantInt::get(IntTy, flags.getBitMask()), |
| getIntSize(), "block.flags"); |
| addHeaderField(llvm::ConstantInt::get(IntTy, 0), getIntSize(), |
| "block.reserved"); |
| } else { |
| addHeaderField( |
| llvm::ConstantInt::get(IntTy, blockInfo.BlockSize.getQuantity()), |
| getIntSize(), "block.size"); |
| addHeaderField( |
| llvm::ConstantInt::get(IntTy, blockInfo.BlockAlign.getQuantity()), |
| getIntSize(), "block.align"); |
| } |
| addHeaderField(blockFn, GenVoidPtrSize, "block.invoke"); |
| if (!IsOpenCL) |
| addHeaderField(descriptor, getPointerSize(), "block.descriptor"); |
| else if (auto *Helper = |
| CGM.getTargetCodeGenInfo().getTargetOpenCLBlockHelper()) { |
| for (auto I : Helper->getCustomFieldValues(*this, blockInfo)) { |
| addHeaderField( |
| I.first, |
| CharUnits::fromQuantity( |
| CGM.getDataLayout().getTypeAllocSize(I.first->getType())), |
| I.second); |
| } |
| } |
| } |
| |
| // Finally, capture all the values into the block. |
| const BlockDecl *blockDecl = blockInfo.getBlockDecl(); |
| |
| // First, 'this'. |
| if (blockDecl->capturesCXXThis()) { |
| Address addr = |
| projectField(blockInfo.CXXThisIndex, "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(), "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.isEscapingByref()) { |
| 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 will just be an i8**. |
| src = Builder.CreateStructGEP(LoadBlockStruct(), |
| enclosingCapture.getIndex(), |
| "block.capture.addr"); |
| } else { |
| auto I = LocalDeclMap.find(variable); |
| assert(I != LocalDeclMap.end()); |
| src = I->second; |
| } |
| } else { |
| DeclRefExpr declRef(getContext(), const_cast<VarDecl *>(variable), |
| /*RefersToEnclosingVariableOrCapture*/ CI.isNested(), |
| type.getNonReferenceType(), VK_LValue, |
| SourceLocation()); |
| src = EmitDeclRefLValue(&declRef).getAddress(*this); |
| }; |
| |
| // 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.isEscapingByref()) { |
| // 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, |
| AggValueSlot::DoesNotOverlap); |
| 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(getContext(), const_cast<VarDecl *>(variable), |
| /*RefersToEnclosingVariableOrCapture*/ CI.isNested(), |
| type, VK_LValue, SourceLocation()); |
| |
| ImplicitCastExpr l2r(ImplicitCastExpr::OnStack, type, CK_LValueToRValue, |
| &declRef, VK_RValue, FPOptionsOverride()); |
| // 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. |
| EmitExprAsInit(&l2r, &BlockFieldPseudoVar, |
| MakeAddrLValue(blockField, type, AlignmentSource::Decl), |
| /*captured by init*/ false); |
| } |
| |
| // Push a cleanup for the capture if necessary. |
| if (!blockInfo.NeedsCopyDispose) |
| continue; |
| |
| // Ignore __block captures; there's nothing special in the on-stack block |
| // that we need to do for them. |
| if (CI.isByRef()) |
| continue; |
| |
| // Ignore objects that aren't destructed. |
| QualType::DestructionKind dtorKind = type.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 (type.isConstQualified() && |
| type.getObjCLifetime() == Qualifiers::OCL_Strong && |
| CGM.getCodeGenOpts().OptimizationLevel != 0) { |
| assert(CGM.getLangOpts().ObjCAutoRefCount && |
| "expected ObjC ARC to be enabled"); |
| destroyer = emitARCIntrinsicUse; |
| } else if (dtorKind == QualType::DK_objc_strong_lifetime) { |
| destroyer = destroyARCStrongImprecise; |
| } else { |
| destroyer = getDestroyer(dtorKind); |
| } |
| |
| CleanupKind cleanupKind = NormalCleanup; |
| bool useArrayEHCleanup = needsEHCleanup(dtorKind); |
| if (useArrayEHCleanup) |
| cleanupKind = NormalAndEHCleanup; |
| |
| // Extend the lifetime of the capture to the end of the scope enclosing the |
| // block expression except when the block decl is in the list of RetExpr's |
| // cleanup objects, in which case its lifetime ends after the full |
| // expression. |
| auto IsBlockDeclInRetExpr = [&]() { |
| auto *EWC = llvm::dyn_cast_or_null<ExprWithCleanups>(RetExpr); |
| if (EWC) |
| for (auto &C : EWC->getObjects()) |
| if (auto *BD = C.dyn_cast<BlockDecl *>()) |
| if (BD == blockDecl) |
| return true; |
| return false; |
| }; |
| |
| if (IsBlockDeclInRetExpr()) |
| pushDestroy(cleanupKind, blockField, type, destroyer, useArrayEHCleanup); |
| else |
| pushLifetimeExtendedDestroy(cleanupKind, blockField, type, destroyer, |
| useArrayEHCleanup); |
| } |
| |
| // 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())); |
| |
| if (IsOpenCL) { |
| CGM.getOpenCLRuntime().recordBlockInfo(blockInfo.BlockExpression, InvokeFn, |
| result); |
| } |
| |
| 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(); |
| |
| if (getLangOpts().OpenCL) { |
| // struct __opencl_block_literal_generic { |
| // int __size; |
| // int __align; |
| // __generic void *__invoke; |
| // /* custom fields */ |
| // }; |
| SmallVector<llvm::Type *, 8> StructFields( |
| {IntTy, IntTy, getOpenCLRuntime().getGenericVoidPointerType()}); |
| if (auto *Helper = getTargetCodeGenInfo().getTargetOpenCLBlockHelper()) { |
| for (auto I : Helper->getCustomFieldTypes()) |
| StructFields.push_back(I); |
| } |
| GenericBlockLiteralType = llvm::StructType::create( |
| StructFields, "struct.__opencl_block_literal_generic"); |
| } else { |
| // 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 auto *BPT = E->getCallee()->getType()->castAs<BlockPointerType>(); |
| llvm::Value *BlockPtr = EmitScalarExpr(E->getCallee()); |
| llvm::Type *GenBlockTy = CGM.getGenericBlockLiteralType(); |
| llvm::Value *Func = nullptr; |
| QualType FnType = BPT->getPointeeType(); |
| ASTContext &Ctx = getContext(); |
| CallArgList Args; |
| |
| if (getLangOpts().OpenCL) { |
| // For OpenCL, BlockPtr is already casted to generic block literal. |
| |
| // First argument of a block call is a generic block literal casted to |
| // generic void pointer, i.e. i8 addrspace(4)* |
| llvm::Value *BlockDescriptor = Builder.CreatePointerCast( |
| BlockPtr, CGM.getOpenCLRuntime().getGenericVoidPointerType()); |
| QualType VoidPtrQualTy = Ctx.getPointerType( |
| Ctx.getAddrSpaceQualType(Ctx.VoidTy, LangAS::opencl_generic)); |
| Args.add(RValue::get(BlockDescriptor), VoidPtrQualTy); |
| // And the rest of the arguments. |
| EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(), E->arguments()); |
| |
| // We *can* call the block directly unless it is a function argument. |
| if (!isa<ParmVarDecl>(E->getCalleeDecl())) |
| Func = CGM.getOpenCLRuntime().getInvokeFunction(E->getCallee()); |
| else { |
| llvm::Value *FuncPtr = Builder.CreateStructGEP(GenBlockTy, BlockPtr, 2); |
| Func = Builder.CreateAlignedLoad(FuncPtr, getPointerAlign()); |
| } |
| } else { |
| // Bitcast the block literal to a generic block literal. |
| BlockPtr = Builder.CreatePointerCast( |
| BlockPtr, llvm::PointerType::get(GenBlockTy, 0), "block.literal"); |
| // Get pointer to the block invoke function |
| llvm::Value *FuncPtr = Builder.CreateStructGEP(GenBlockTy, BlockPtr, 3); |
| |
| // First argument is a block literal casted to a void pointer |
| BlockPtr = Builder.CreatePointerCast(BlockPtr, VoidPtrTy); |
| Args.add(RValue::get(BlockPtr), Ctx.VoidPtrTy); |
| // And the rest of the arguments. |
| EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(), E->arguments()); |
| |
| // Load the function. |
| 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.CreatePointerCast(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) { |
| 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(), |
| "block.capture.addr"); |
| |
| if (variable->isEscapingByref()) { |
| // 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()); |
| } |
| |
| assert((!variable->isNonEscapingByref() || |
| capture.fieldType()->isReferenceType()) && |
| "the capture field of a non-escaping variable should have a " |
| "reference type"); |
| if (capture.fieldType()->isReferenceType()) |
| addr = EmitLoadOfReference(MakeAddrLValue(addr, capture.fieldType())); |
| |
| 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. |
| { |
| CodeGenFunction::DeclMapTy LocalDeclMap; |
| CodeGenFunction(*this).GenerateBlockFunction( |
| GlobalDecl(), blockInfo, LocalDeclMap, |
| /*IsLambdaConversionToBlock*/ false, /*BuildGlobalBlock*/ true); |
| } |
| |
| return getAddrOfGlobalBlockIfEmitted(BE); |
| } |
| |
| 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(); |
| |
| bool IsOpenCL = CGM.getLangOpts().OpenCL; |
| bool IsWindows = CGM.getTarget().getTriple().isOSWindows(); |
| if (!IsOpenCL) { |
| // isa |
| if (IsWindows) |
| fields.addNullPointer(CGM.Int8PtrPtrTy); |
| else |
| fields.add(CGM.getNSConcreteGlobalBlock()); |
| |
| // __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); |
| } else { |
| fields.addInt(CGM.IntTy, blockInfo.BlockSize.getQuantity()); |
| fields.addInt(CGM.IntTy, blockInfo.BlockAlign.getQuantity()); |
| } |
| |
| // Function |
| fields.add(blockFn); |
| |
| if (!IsOpenCL) { |
| // Descriptor |
| fields.add(buildBlockDescriptor(CGM, blockInfo)); |
| } else if (auto *Helper = |
| CGM.getTargetCodeGenInfo().getTargetOpenCLBlockHelper()) { |
| for (auto I : Helper->getCustomFieldValues(CGM, blockInfo)) { |
| fields.add(I); |
| } |
| } |
| |
| unsigned AddrSpace = 0; |
| if (CGM.getContext().getLangOpts().OpenCL) |
| AddrSpace = CGM.getContext().getTargetAddressSpace(LangAS::opencl_global); |
| |
| llvm::GlobalVariable *literal = fields.finishAndCreateGlobal( |
| "__block_literal_global", blockInfo.BlockAlign, |
| /*constant*/ !IsWindows, llvm::GlobalVariable::InternalLinkage, AddrSpace); |
| |
| literal->addAttribute("objc_arc_inert"); |
| |
| // Windows does not allow globals to be initialised to point to globals in |
| // different DLLs. Any such variables must run code to initialise them. |
| if (IsWindows) { |
| auto *Init = llvm::Function::Create(llvm::FunctionType::get(CGM.VoidTy, |
| {}), llvm::GlobalValue::InternalLinkage, ".block_isa_init", |
| &CGM.getModule()); |
| llvm::IRBuilder<> b(llvm::BasicBlock::Create(CGM.getLLVMContext(), "entry", |
| Init)); |
| b.CreateAlignedStore(CGM.getNSConcreteGlobalBlock(), |
| b.CreateStructGEP(literal, 0), |
| CGM.getPointerAlign().getAsAlign()); |
| b.CreateRetVoid(); |
| // We can't use the normal LLVM global initialisation array, because we |
| // need to specify that this runs early in library initialisation. |
| auto *InitVar = new llvm::GlobalVariable(CGM.getModule(), Init->getType(), |
| /*isConstant*/true, llvm::GlobalValue::InternalLinkage, |
| Init, ".block_isa_init_ptr"); |
| InitVar->setSection(".CRT$XCLa"); |
| CGM.addUsedGlobal(InitVar); |
| } |
| |
| // 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); |
| if (CGM.getContext().getLangOpts().OpenCL) |
| CGM.getOpenCLRuntime().recordBlockInfo( |
| blockInfo.BlockExpression, |
| cast<llvm::Function>(blockFn->stripPointerCasts()), Result); |
| return Result; |
| } |
| |
| void CodeGenFunction::setBlockContextParameter(const ImplicitParamDecl *D, |
| unsigned argNum, |
| llvm::Value *arg) { |
| assert(BlockInfo && "not emitting prologue of block invocation function?!"); |
| |
| // Allocate a stack slot like for any local variable to guarantee optimal |
| // debug info at -O0. The mem2reg pass will eliminate it when optimizing. |
| Address alloc = CreateMemTemp(D->getType(), D->getName() + ".addr"); |
| Builder.CreateStore(arg, alloc); |
| if (CGDebugInfo *DI = getDebugInfo()) { |
| if (CGM.getCodeGenOpts().hasReducedDebugInfo()) { |
| DI->setLocation(D->getLocation()); |
| DI->EmitDeclareOfBlockLiteralArgVariable( |
| *BlockInfo, D->getName(), argNum, |
| cast<llvm::AllocaInst>(alloc.getPointer()), Builder); |
| } |
| } |
| |
| SourceLocation StartLoc = BlockInfo->getBlockExpr()->getBody()->getBeginLoc(); |
| 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, |
| bool BuildGlobalBlock) { |
| const BlockDecl *blockDecl = blockInfo.getBlockDecl(); |
| |
| CurGD = GD; |
| |
| CurEHLocation = blockInfo.getBlockExpr()->getEndLoc(); |
| |
| 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); |
| |
| if (BuildGlobalBlock) { |
| auto GenVoidPtrTy = getContext().getLangOpts().OpenCL |
| ? CGM.getOpenCLRuntime().getGenericVoidPointerType() |
| : VoidPtrTy; |
| buildGlobalBlock(CGM, blockInfo, |
| llvm::ConstantExpr::getPointerCast(fn, GenVoidPtrTy)); |
| } |
| |
| // Begin generating the function. |
| StartFunction(blockDecl, fnType->getReturnType(), fn, fnInfo, args, |
| blockDecl->getLocation(), |
| blockInfo.getBlockExpr()->getBody()->getBeginLoc()); |
| |
| // 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, "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().hasReducedDebugInfo()) { |
| const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable); |
| if (capture.isConstant()) { |
| auto addr = LocalDeclMap.find(variable)->second; |
| (void)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; |
| } |
| |
| 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.isEscapingByref()) { |
| Flags = BLOCK_FIELD_IS_BYREF; |
| if (T.isObjCGCWeak()) |
| Flags |= BLOCK_FIELD_IS_WEAK; |
| return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags); |
| } |
| |
| Flags = BLOCK_FIELD_IS_OBJECT; |
| bool isBlockPointer = T->isBlockPointerType(); |
| if (isBlockPointer) |
| Flags = BLOCK_FIELD_IS_BLOCK; |
| |
| switch (T.isNonTrivialToPrimitiveCopy()) { |
| case QualType::PCK_Struct: |
| return std::make_pair(BlockCaptureEntityKind::NonTrivialCStruct, |
| BlockFieldFlags()); |
| case QualType::PCK_ARCWeak: |
| // We need to register __weak direct captures with the runtime. |
| return std::make_pair(BlockCaptureEntityKind::ARCWeak, Flags); |
| case QualType::PCK_ARCStrong: |
| // We need to retain the copied value for __strong direct captures. |
| // 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); |
| case QualType::PCK_Trivial: |
| case QualType::PCK_VolatileTrivial: { |
| if (!T->isObjCRetainableType()) |
| // For all other types, the memcpy is fine. |
| return std::make_pair(BlockCaptureEntityKind::None, BlockFieldFlags()); |
| |
| // Special rules for ARC captures: |
| Qualifiers QS = T.getQualifiers(); |
| |
| // 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, BlockFieldFlags()); |
| } |
| } |
| llvm_unreachable("after exhaustive PrimitiveCopyKind switch"); |
| } |
| |
| static std::pair<BlockCaptureEntityKind, BlockFieldFlags> |
| computeDestroyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T, |
| const LangOptions &LangOpts); |
| |
| /// 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) { |
| for (const auto &CI : BlockInfo.getBlockDecl()->captures()) { |
| const VarDecl *Variable = CI.getVariable(); |
| const CGBlockInfo::Capture &Capture = BlockInfo.getCapture(Variable); |
| if (Capture.isConstant()) |
| continue; |
| |
| QualType VT = Capture.fieldType(); |
| auto CopyInfo = computeCopyInfoForBlockCapture(CI, VT, LangOpts); |
| auto DisposeInfo = computeDestroyInfoForBlockCapture(CI, VT, LangOpts); |
| if (CopyInfo.first != BlockCaptureEntityKind::None || |
| DisposeInfo.first != BlockCaptureEntityKind::None) |
| ManagedCaptures.emplace_back(CopyInfo.first, DisposeInfo.first, |
| CopyInfo.second, DisposeInfo.second, CI, |
| Capture); |
| } |
| |
| // Sort the captures by offset. |
| llvm::sort(ManagedCaptures); |
| } |
| |
| namespace { |
| /// Release a __block variable. |
| struct CallBlockRelease final : EHScopeStack::Cleanup { |
| Address Addr; |
| BlockFieldFlags FieldFlags; |
| bool LoadBlockVarAddr, CanThrow; |
| |
| CallBlockRelease(Address Addr, BlockFieldFlags Flags, bool LoadValue, |
| bool CT) |
| : Addr(Addr), FieldFlags(Flags), LoadBlockVarAddr(LoadValue), |
| CanThrow(CT) {} |
| |
| void Emit(CodeGenFunction &CGF, Flags flags) override { |
| llvm::Value *BlockVarAddr; |
| if (LoadBlockVarAddr) { |
| BlockVarAddr = CGF.Builder.CreateLoad(Addr); |
| BlockVarAddr = CGF.Builder.CreateBitCast(BlockVarAddr, CGF.VoidPtrTy); |
| } else { |
| BlockVarAddr = Addr.getPointer(); |
| } |
| |
| CGF.BuildBlockRelease(BlockVarAddr, FieldFlags, CanThrow); |
| } |
| }; |
| } // end anonymous namespace |
| |
| /// Check if \p T is a C++ class that has a destructor that can throw. |
| bool CodeGenFunction::cxxDestructorCanThrow(QualType T) { |
| if (const auto *RD = T->getAsCXXRecordDecl()) |
| if (const CXXDestructorDecl *DD = RD->getDestructor()) |
| return DD->getType()->castAs<FunctionProtoType>()->canThrow(); |
| return false; |
| } |
| |
| // Return a string that has the information about a capture. |
| static std::string getBlockCaptureStr(const BlockCaptureManagedEntity &E, |
| CaptureStrKind StrKind, |
| CharUnits BlockAlignment, |
| CodeGenModule &CGM) { |
| std::string Str; |
| ASTContext &Ctx = CGM.getContext(); |
| const BlockDecl::Capture &CI = *E.CI; |
| QualType CaptureTy = CI.getVariable()->getType(); |
| |
| BlockCaptureEntityKind Kind; |
| BlockFieldFlags Flags; |
| |
| // CaptureStrKind::Merged should be passed only when the operations and the |
| // flags are the same for copy and dispose. |
| assert((StrKind != CaptureStrKind::Merged || |
| (E.CopyKind == E.DisposeKind && E.CopyFlags == E.DisposeFlags)) && |
| "different operations and flags"); |
| |
| if (StrKind == CaptureStrKind::DisposeHelper) { |
| Kind = E.DisposeKind; |
| Flags = E.DisposeFlags; |
| } else { |
| Kind = E.CopyKind; |
| Flags = E.CopyFlags; |
| } |
| |
| switch (Kind) { |
| case BlockCaptureEntityKind::CXXRecord: { |
| Str += "c"; |
| SmallString<256> TyStr; |
| llvm::raw_svector_ostream Out(TyStr); |
| CGM.getCXXABI().getMangleContext().mangleTypeName(CaptureTy, Out); |
| Str += llvm::to_string(TyStr.size()) + TyStr.c_str(); |
| break; |
| } |
| case BlockCaptureEntityKind::ARCWeak: |
| Str += "w"; |
| break; |
| case BlockCaptureEntityKind::ARCStrong: |
| Str += "s"; |
| break; |
| case BlockCaptureEntityKind::BlockObject: { |
| const VarDecl *Var = CI.getVariable(); |
| unsigned F = Flags.getBitMask(); |
| if (F & BLOCK_FIELD_IS_BYREF) { |
| Str += "r"; |
| if (F & BLOCK_FIELD_IS_WEAK) |
| Str += "w"; |
| else { |
| // If CaptureStrKind::Merged is passed, check both the copy expression |
| // and the destructor. |
| if (StrKind != CaptureStrKind::DisposeHelper) { |
| if (Ctx.getBlockVarCopyInit(Var).canThrow()) |
| Str += "c"; |
| } |
| if (StrKind != CaptureStrKind::CopyHelper) { |
| if (CodeGenFunction::cxxDestructorCanThrow(CaptureTy)) |
| Str += "d"; |
| } |
| } |
| } else { |
| assert((F & BLOCK_FIELD_IS_OBJECT) && "unexpected flag value"); |
| if (F == BLOCK_FIELD_IS_BLOCK) |
| Str += "b"; |
| else |
| Str += "o"; |
| } |
| break; |
| } |
| case BlockCaptureEntityKind::NonTrivialCStruct: { |
| bool IsVolatile = CaptureTy.isVolatileQualified(); |
| CharUnits Alignment = |
| BlockAlignment.alignmentAtOffset(E.Capture->getOffset()); |
| |
| Str += "n"; |
| std::string FuncStr; |
| if (StrKind == CaptureStrKind::DisposeHelper) |
| FuncStr = CodeGenFunction::getNonTrivialDestructorStr( |
| CaptureTy, Alignment, IsVolatile, Ctx); |
| else |
| // If CaptureStrKind::Merged is passed, use the copy constructor string. |
| // It has all the information that the destructor string has. |
| FuncStr = CodeGenFunction::getNonTrivialCopyConstructorStr( |
| CaptureTy, Alignment, IsVolatile, Ctx); |
| // The underscore is necessary here because non-trivial copy constructor |
| // and destructor strings can start with a number. |
| Str += llvm::to_string(FuncStr.size()) + "_" + FuncStr; |
| break; |
| } |
| case BlockCaptureEntityKind::None: |
| break; |
| } |
| |
| return Str; |
| } |
| |
| static std::string getCopyDestroyHelperFuncName( |
| const SmallVectorImpl<BlockCaptureManagedEntity> &Captures, |
| CharUnits BlockAlignment, CaptureStrKind StrKind, CodeGenModule &CGM) { |
| assert((StrKind == CaptureStrKind::CopyHelper || |
| StrKind == CaptureStrKind::DisposeHelper) && |
| "unexpected CaptureStrKind"); |
| std::string Name = StrKind == CaptureStrKind::CopyHelper |
| ? "__copy_helper_block_" |
| : "__destroy_helper_block_"; |
| if (CGM.getLangOpts().Exceptions) |
| Name += "e"; |
| if (CGM.getCodeGenOpts().ObjCAutoRefCountExceptions) |
| Name += "a"; |
| Name += llvm::to_string(BlockAlignment.getQuantity()) + "_"; |
| |
| for (const BlockCaptureManagedEntity &E : Captures) { |
| Name += llvm::to_string(E.Capture->getOffset().getQuantity()); |
| Name += getBlockCaptureStr(E, StrKind, BlockAlignment, CGM); |
| } |
| |
| return Name; |
| } |
| |
| static void pushCaptureCleanup(BlockCaptureEntityKind CaptureKind, |
| Address Field, QualType CaptureType, |
| BlockFieldFlags Flags, bool ForCopyHelper, |
| VarDecl *Var, CodeGenFunction &CGF) { |
| bool EHOnly = ForCopyHelper; |
| |
| switch (CaptureKind) { |
| case BlockCaptureEntityKind::CXXRecord: |
| case BlockCaptureEntityKind::ARCWeak: |
| case BlockCaptureEntityKind::NonTrivialCStruct: |
| case BlockCaptureEntityKind::ARCStrong: { |
| if (CaptureType.isDestructedType() && |
| (!EHOnly || CGF.needsEHCleanup(CaptureType.isDestructedType()))) { |
| CodeGenFunction::Destroyer *Destroyer = |
| CaptureKind == BlockCaptureEntityKind::ARCStrong |
| ? CodeGenFunction::destroyARCStrongImprecise |
| : CGF.getDestroyer(CaptureType.isDestructedType()); |
| CleanupKind Kind = |
| EHOnly ? EHCleanup |
| : CGF.getCleanupKind(CaptureType.isDestructedType()); |
| CGF.pushDestroy(Kind, Field, CaptureType, Destroyer, Kind & EHCleanup); |
| } |
| break; |
| } |
| case BlockCaptureEntityKind::BlockObject: { |
| if (!EHOnly || CGF.getLangOpts().Exceptions) { |
| CleanupKind Kind = EHOnly ? EHCleanup : NormalAndEHCleanup; |
| // Calls to _Block_object_dispose along the EH path in the copy helper |
| // function don't throw as newly-copied __block variables always have a |
| // reference count of 2. |
| bool CanThrow = |
| !ForCopyHelper && CGF.cxxDestructorCanThrow(CaptureType); |
| CGF.enterByrefCleanup(Kind, Field, Flags, /*LoadBlockVarAddr*/ true, |
| CanThrow); |
| } |
| break; |
| } |
| case BlockCaptureEntityKind::None: |
| break; |
| } |
| } |
| |
| static void setBlockHelperAttributesVisibility(bool CapturesNonExternalType, |
| llvm::Function *Fn, |
| const CGFunctionInfo &FI, |
| CodeGenModule &CGM) { |
| if (CapturesNonExternalType) { |
| CGM.SetInternalFunctionAttributes(GlobalDecl(), Fn, FI); |
| } else { |
| Fn->setVisibility(llvm::GlobalValue::HiddenVisibility); |
| Fn->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global); |
| CGM.SetLLVMFunctionAttributes(GlobalDecl(), FI, Fn); |
| CGM.SetLLVMFunctionAttributesForDefinition(nullptr, Fn); |
| } |
| } |
| /// 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) { |
| SmallVector<BlockCaptureManagedEntity, 4> CopiedCaptures; |
| findBlockCapturedManagedEntities(blockInfo, getLangOpts(), CopiedCaptures); |
| std::string FuncName = |
| getCopyDestroyHelperFuncName(CopiedCaptures, blockInfo.BlockAlign, |
| CaptureStrKind::CopyHelper, CGM); |
| |
| if (llvm::GlobalValue *Func = CGM.getModule().getNamedValue(FuncName)) |
| return llvm::ConstantExpr::getBitCast(Func, VoidPtrTy); |
| |
| ASTContext &C = getContext(); |
| |
| QualType ReturnTy = C.VoidTy; |
| |
| FunctionArgList args; |
| ImplicitParamDecl DstDecl(C, C.VoidPtrTy, ImplicitParamDecl::Other); |
| args.push_back(&DstDecl); |
| ImplicitParamDecl SrcDecl(C, C.VoidPtrTy, ImplicitParamDecl::Other); |
| args.push_back(&SrcDecl); |
| |
| const CGFunctionInfo &FI = |
| CGM.getTypes().arrangeBuiltinFunctionDeclaration(ReturnTy, 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::LinkOnceODRLinkage, |
| FuncName, &CGM.getModule()); |
| if (CGM.supportsCOMDAT()) |
| Fn->setComdat(CGM.getModule().getOrInsertComdat(FuncName)); |
| |
| IdentifierInfo *II = &C.Idents.get(FuncName); |
| |
| SmallVector<QualType, 2> ArgTys; |
| ArgTys.push_back(C.VoidPtrTy); |
| ArgTys.push_back(C.VoidPtrTy); |
| QualType FunctionTy = C.getFunctionType(ReturnTy, ArgTys, {}); |
| |
| FunctionDecl *FD = FunctionDecl::Create( |
| C, C.getTranslationUnitDecl(), SourceLocation(), SourceLocation(), II, |
| FunctionTy, nullptr, SC_Static, false, false); |
| setBlockHelperAttributesVisibility(blockInfo.CapturesNonExternalType, Fn, FI, |
| CGM); |
| // This is necessary to avoid inheriting the previous line number. |
| FD->setImplicit(); |
| StartFunction(FD, ReturnTy, 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.source"); |
| |
| Address dst = GetAddrOfLocalVar(&DstDecl); |
| dst = Address(Builder.CreateLoad(dst), blockInfo.BlockAlign); |
| dst = Builder.CreateBitCast(dst, structPtrTy, "block.dest"); |
| |
| for (const auto &CopiedCapture : CopiedCaptures) { |
| const BlockDecl::Capture &CI = *CopiedCapture.CI; |
| const CGBlockInfo::Capture &capture = *CopiedCapture.Capture; |
| QualType captureType = CI.getVariable()->getType(); |
| BlockFieldFlags flags = CopiedCapture.CopyFlags; |
| |
| unsigned index = capture.getIndex(); |
| Address srcField = Builder.CreateStructGEP(src, index); |
| Address dstField = Builder.CreateStructGEP(dst, index); |
| |
| switch (CopiedCapture.CopyKind) { |
| case BlockCaptureEntityKind::CXXRecord: |
| // If there's an explicit copy expression, we do that. |
| assert(CI.getCopyExpr() && "copy expression for variable is missing"); |
| EmitSynthesizedCXXCopyCtor(dstField, srcField, CI.getCopyExpr()); |
| break; |
| case BlockCaptureEntityKind::ARCWeak: |
| EmitARCCopyWeak(dstField, srcField); |
| break; |
| case BlockCaptureEntityKind::NonTrivialCStruct: { |
| // If this is a C struct that requires non-trivial copy construction, |
| // emit a call to its copy constructor. |
| QualType varType = CI.getVariable()->getType(); |
| callCStructCopyConstructor(MakeAddrLValue(dstField, varType), |
| MakeAddrLValue(srcField, varType)); |
| break; |
| } |
| case BlockCaptureEntityKind::ARCStrong: { |
| llvm::Value *srcValue = Builder.CreateLoad(srcField, "blockcopy.src"); |
| // 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); |
| |
| // Unless EH cleanup is required, we don't need this anymore, so kill |
| // it. It's not quite worth the annoyance to avoid creating it in the |
| // first place. |
| if (!needsEHCleanup(captureType.isDestructedType())) |
| cast<llvm::Instruction>(dstField.getPointer())->eraseFromParent(); |
| } |
| break; |
| } |
| case BlockCaptureEntityKind::BlockObject: { |
| llvm::Value *srcValue = Builder.CreateLoad(srcField, "blockcopy.src"); |
| srcValue = Builder.CreateBitCast(srcValue, VoidPtrTy); |
| llvm::Value *dstAddr = |
| Builder.CreateBitCast(dstField.getPointer(), VoidPtrTy); |
| llvm::Value *args[] = { |
| dstAddr, srcValue, llvm::ConstantInt::get(Int32Ty, flags.getBitMask()) |
| }; |
| |
| if (CI.isByRef() && C.getBlockVarCopyInit(CI.getVariable()).canThrow()) |
| EmitRuntimeCallOrInvoke(CGM.getBlockObjectAssign(), args); |
| else |
| EmitNounwindRuntimeCall(CGM.getBlockObjectAssign(), args); |
| break; |
| } |
| case BlockCaptureEntityKind::None: |
| continue; |
| } |
| |
| // Ensure that we destroy the copied object if an exception is thrown later |
| // in the helper function. |
| pushCaptureCleanup(CopiedCapture.CopyKind, dstField, captureType, flags, |
| /*ForCopyHelper*/ true, CI.getVariable(), *this); |
| } |
| |
| FinishFunction(); |
| |
| return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy); |
| } |
| |
| static BlockFieldFlags |
| getBlockFieldFlagsForObjCObjectPointer(const BlockDecl::Capture &CI, |
| QualType T) { |
| BlockFieldFlags Flags = BLOCK_FIELD_IS_OBJECT; |
| if (T->isBlockPointerType()) |
| Flags = BLOCK_FIELD_IS_BLOCK; |
| return Flags; |
| } |
| |
| static std::pair<BlockCaptureEntityKind, BlockFieldFlags> |
| computeDestroyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T, |
| const LangOptions &LangOpts) { |
| if (CI.isEscapingByref()) { |
| BlockFieldFlags Flags = BLOCK_FIELD_IS_BYREF; |
| if (T.isObjCGCWeak()) |
| Flags |= BLOCK_FIELD_IS_WEAK; |
| return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags); |
| } |
| |
| switch (T.isDestructedType()) { |
| case QualType::DK_cxx_destructor: |
| return std::make_pair(BlockCaptureEntityKind::CXXRecord, BlockFieldFlags()); |
| case QualType::DK_objc_strong_lifetime: |
| // Use objc_storeStrong for __strong direct captures; the |
| // dynamic tools really like it when we do this. |
| return std::make_pair(BlockCaptureEntityKind::ARCStrong, |
| getBlockFieldFlagsForObjCObjectPointer(CI, T)); |
| case QualType::DK_objc_weak_lifetime: |
| // Support __weak direct captures. |
| return std::make_pair(BlockCaptureEntityKind::ARCWeak, |
| getBlockFieldFlagsForObjCObjectPointer(CI, T)); |
| case QualType::DK_nontrivial_c_struct: |
| return std::make_pair(BlockCaptureEntityKind::NonTrivialCStruct, |
| BlockFieldFlags()); |
| case QualType::DK_none: { |
| // Non-ARC captures are strong, and we need to use _Block_object_dispose. |
| if (T->isObjCRetainableType() && !T.getQualifiers().hasObjCLifetime() && |
| !LangOpts.ObjCAutoRefCount) |
| return std::make_pair(BlockCaptureEntityKind::BlockObject, |
| getBlockFieldFlagsForObjCObjectPointer(CI, T)); |
| // Otherwise, we have nothing to do. |
| return std::make_pair(BlockCaptureEntityKind::None, BlockFieldFlags()); |
| } |
| } |
| llvm_unreachable("after exhaustive DestructionKind switch"); |
| } |
| |
| /// 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) { |
| SmallVector<BlockCaptureManagedEntity, 4> DestroyedCaptures; |
| findBlockCapturedManagedEntities(blockInfo, getLangOpts(), DestroyedCaptures); |
| std::string FuncName = |
| getCopyDestroyHelperFuncName(DestroyedCaptures, blockInfo.BlockAlign, |
| CaptureStrKind::DisposeHelper, CGM); |
| |
| if (llvm::GlobalValue *Func = CGM.getModule().getNamedValue(FuncName)) |
| return llvm::ConstantExpr::getBitCast(Func, VoidPtrTy); |
| |
| ASTContext &C = getContext(); |
| |
| QualType ReturnTy = C.VoidTy; |
| |
| FunctionArgList args; |
| ImplicitParamDecl SrcDecl(C, C.VoidPtrTy, ImplicitParamDecl::Other); |
| args.push_back(&SrcDecl); |
| |
| const CGFunctionInfo &FI = |
| CGM.getTypes().arrangeBuiltinFunctionDeclaration(ReturnTy, 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::LinkOnceODRLinkage, |
| FuncName, &CGM.getModule()); |
| if (CGM.supportsCOMDAT()) |
| Fn->setComdat(CGM.getModule().getOrInsertComdat(FuncName)); |
| |
| IdentifierInfo *II = &C.Idents.get(FuncName); |
| |
| SmallVector<QualType, 1> ArgTys; |
| ArgTys.push_back(C.VoidPtrTy); |
| QualType FunctionTy = C.getFunctionType(ReturnTy, ArgTys, {}); |
| |
| FunctionDecl *FD = FunctionDecl::Create( |
| C, C.getTranslationUnitDecl(), SourceLocation(), SourceLocation(), II, |
| FunctionTy, nullptr, SC_Static, false, false); |
| |
| setBlockHelperAttributesVisibility(blockInfo.CapturesNonExternalType, Fn, FI, |
| CGM); |
| // This is necessary to avoid inheriting the previous line number. |
| FD->setImplicit(); |
| StartFunction(FD, ReturnTy, Fn, FI, args); |
| markAsIgnoreThreadCheckingAtRuntime(Fn); |
| |
| 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); |
| |
| for (const auto &DestroyedCapture : DestroyedCaptures) { |
| const BlockDecl::Capture &CI = *DestroyedCapture.CI; |
| const CGBlockInfo::Capture &capture = *DestroyedCapture.Capture; |
| BlockFieldFlags flags = DestroyedCapture.DisposeFlags; |
| |
| Address srcField = Builder.CreateStructGEP(src, capture.getIndex()); |
| |
| pushCaptureCleanup(DestroyedCapture.DisposeKind, srcField, |
| CI.getVariable()->getType(), flags, |
| /*ForCopyHelper*/ false, CI.getVariable(), *this); |
| } |
| |
| 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::FunctionCallee 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, false); |
| } |
| |
| 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()); |
| } |
| }; |
| |
| /// Emits the copy/dispose helpers for a __block variable that is a non-trivial |
| /// C struct. |
| class NonTrivialCStructByrefHelpers final : public BlockByrefHelpers { |
| QualType VarType; |
| |
| public: |
| NonTrivialCStructByrefHelpers(CharUnits alignment, QualType type) |
| : BlockByrefHelpers(alignment), VarType(type) {} |
| |
| void emitCopy(CodeGenFunction &CGF, Address destField, |
| Address srcField) override { |
| CGF.callCStructMoveConstructor(CGF.MakeAddrLValue(destField, VarType), |
| CGF.MakeAddrLValue(srcField, VarType)); |
| } |
| |
| bool needsDispose() const override { |
| return VarType.isDestructedType(); |
| } |
| |
| void emitDispose(CodeGenFunction &CGF, Address field) override { |
| EHScopeStack::stable_iterator cleanupDepth = CGF.EHStack.stable_begin(); |
| CGF.pushDestroy(VarType.isDestructedType(), field, VarType); |
| 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 ReturnTy = Context.VoidTy; |
| |
| FunctionArgList args; |
| ImplicitParamDecl Dst(Context, Context.VoidPtrTy, ImplicitParamDecl::Other); |
| args.push_back(&Dst); |
| |
| ImplicitParamDecl Src(Context, Context.VoidPtrTy, ImplicitParamDecl::Other); |
| args.push_back(&Src); |
| |
| const CGFunctionInfo &FI = |
| CGF.CGM.getTypes().arrangeBuiltinFunctionDeclaration(ReturnTy, 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_"); |
| |
| SmallVector<QualType, 2> ArgTys; |
| ArgTys.push_back(Context.VoidPtrTy); |
| ArgTys.push_back(Context.VoidPtrTy); |
| QualType FunctionTy = Context.getFunctionType(ReturnTy, ArgTys, {}); |
| |
| FunctionDecl *FD = FunctionDecl::Create( |
| Context, Context.getTranslationUnitDecl(), SourceLocation(), |
| SourceLocation(), II, FunctionTy, nullptr, SC_Static, false, false); |
| |
| CGF.CGM.SetInternalFunctionAttributes(GlobalDecl(), Fn, FI); |
| |
| CGF.StartFunction(FD, ReturnTy, 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_"); |
| |
| SmallVector<QualType, 1> ArgTys; |
| ArgTys.push_back(Context.VoidPtrTy); |
| QualType FunctionTy = Context.getFunctionType(R, ArgTys, {}); |
| |
| FunctionDecl *FD = FunctionDecl::Create( |
| Context, Context.getTranslationUnitDecl(), SourceLocation(), |
| SourceLocation(), II, FunctionTy, nullptr, SC_Static, false, false); |
| |
| CGF.CGM.SetInternalFunctionAttributes(GlobalDecl(), 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; |
| assert(var.isEscapingByref() && |
| "only escaping __block variables need byref helpers"); |
| |
| 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().getBlockVarCopyInit(&var).getCopyExpr(); |
| if (!copyExpr && record->hasTrivialDestructor()) return nullptr; |
| |
| return ::buildByrefHelpers( |
| CGM, byrefInfo, CXXByrefHelpers(valueAlignment, type, copyExpr)); |
| } |
| |
| // If type is a non-trivial C struct type that is non-trivial to |
| // destructly move or destroy, build the copy and dispose helpers. |
| if (type.isNonTrivialToPrimitiveDestructiveMove() == QualType::PCK_Struct || |
| type.isDestructedType() == QualType::DK_nontrivial_c_struct) |
| return ::buildByrefHelpers( |
| CGM, byrefInfo, NonTrivialCStructByrefHelpers(valueAlignment, type)); |
| |
| // 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, "forwarding"); |
| baseAddr = Address(Builder.CreateLoad(forwardingAddr), info.ByrefAlignment); |
| } |
| |
| return Builder.CreateStructGEP(baseAddr, info.FieldIndex, 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, |
| |