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llvm-project/clang/lib/CodeGen/CGBlocks.cpp

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//===--- CGBlocks.cpp - Emit LLVM Code for declarations -------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit blocks.
//
//===----------------------------------------------------------------------===//
#include "CGDebugInfo.h"
#include "CodeGenFunction.h"
#include "CGObjCRuntime.h"
#include "CodeGenModule.h"
#include "CGBlocks.h"
#include "clang/AST/DeclObjC.h"
#include "llvm/Module.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/Target/TargetData.h"
#include <algorithm>
using namespace clang;
using namespace CodeGen;
CGBlockInfo::CGBlockInfo(const BlockExpr *blockExpr, const char *N)
: Name(N), CXXThisIndex(0), CanBeGlobal(false), NeedsCopyDispose(false),
HasCXXObject(false), UsesStret(false), StructureType(0), Block(blockExpr) {
// Skip asm prefix, if any.
if (Name && Name[0] == '\01')
++Name;
}
/// 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 dipose of a block.
static llvm::Constant *buildDisposeHelper(CodeGenModule &CGM,
const CGBlockInfo &blockInfo) {
return CodeGenFunction(CGM).GenerateDestroyHelperFunction(blockInfo);
}
/// Build the block descriptor constant for a block.
static llvm::Constant *buildBlockDescriptor(CodeGenModule &CGM,
const CGBlockInfo &blockInfo) {
ASTContext &C = CGM.getContext();
const llvm::Type *ulong = CGM.getTypes().ConvertType(C.UnsignedLongTy);
const llvm::Type *i8p = CGM.getTypes().ConvertType(C.VoidPtrTy);
llvm::SmallVector<llvm::Constant*, 6> elements;
// reserved
elements.push_back(llvm::ConstantInt::get(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.push_back(llvm::ConstantInt::get(ulong,
blockInfo.BlockSize.getQuantity()));
// Optional copy/dispose helpers.
if (blockInfo.NeedsCopyDispose) {
// copy_func_helper_decl
elements.push_back(buildCopyHelper(CGM, blockInfo));
// destroy_func_decl
elements.push_back(buildDisposeHelper(CGM, blockInfo));
}
// Signature. Mandatory ObjC-style method descriptor @encode sequence.
std::string typeAtEncoding =
CGM.getContext().getObjCEncodingForBlock(blockInfo.getBlockExpr());
elements.push_back(llvm::ConstantExpr::getBitCast(
CGM.GetAddrOfConstantCString(typeAtEncoding), i8p));
// GC layout.
if (C.getLangOptions().ObjC1)
elements.push_back(CGM.getObjCRuntime().BuildGCBlockLayout(CGM, blockInfo));
else
elements.push_back(llvm::Constant::getNullValue(i8p));
llvm::Constant *init =
llvm::ConstantStruct::get(CGM.getLLVMContext(), elements.data(),
elements.size(), false);
llvm::GlobalVariable *global =
new llvm::GlobalVariable(CGM.getModule(), init->getType(), true,
llvm::GlobalValue::InternalLinkage,
init, "__block_descriptor_tmp");
return llvm::ConstantExpr::getBitCast(global, CGM.getBlockDescriptorType());
}
/*
Purely notional variadic template describing the layout of a block.
template <class _ResultType, class... _ParamTypes, class... _CaptureTypes>
struct Block_literal {
/// Initialized to one of:
/// extern void *_NSConcreteStackBlock[];
/// extern void *_NSConcreteGlobalBlock[];
///
/// In theory, we could start one off malloc'ed by setting
/// BLOCK_NEEDS_FREE, giving it a refcount of 1, and using
/// this isa:
/// extern void *_NSConcreteMallocBlock[];
struct objc_class *isa;
/// These are the flags (with corresponding bit number) that the
/// compiler is actually supposed to know about.
/// 25. BLOCK_HAS_COPY_DISPOSE - indicates that the block
/// descriptor provides copy and dispose helper functions
/// 26. BLOCK_HAS_CXX_OBJ - indicates that there's a captured
/// object with a nontrivial destructor or copy constructor
/// 28. BLOCK_IS_GLOBAL - indicates that the block is allocated
/// as global memory
/// 29. BLOCK_USE_STRET - indicates that the block function
/// uses stret, which objc_msgSend needs to know about
/// 30. BLOCK_HAS_SIGNATURE - indicates that the block has an
/// @encoded signature string
/// And we're not supposed to manipulate these:
/// 24. BLOCK_NEEDS_FREE - indicates that the block has been moved
/// to malloc'ed memory
/// 27. BLOCK_IS_GC - indicates that the block has been moved to
/// to GC-allocated memory
/// Additionally, the bottom 16 bits are a reference count which
/// should be zero on the stack.
int flags;
/// Reserved; should be zero-initialized.
int reserved;
/// Function pointer generated from block literal.
_ResultType (*invoke)(Block_literal *, _ParamTypes...);
/// Block description metadata generated from block literal.
struct Block_descriptor *block_descriptor;
/// Captured values follow.
_CapturesTypes captures...;
};
*/
/// The number of fields in a block header.
const unsigned BlockHeaderSize = 5;
namespace {
/// A chunk of data that we actually have to capture in the block.
struct BlockLayoutChunk {
CharUnits Alignment;
CharUnits Size;
const BlockDecl::Capture *Capture; // null for 'this'
const llvm::Type *Type;
BlockLayoutChunk(CharUnits align, CharUnits size,
const BlockDecl::Capture *capture,
const llvm::Type *type)
: Alignment(align), Size(size), Capture(capture), Type(type) {}
/// Tell the block info that this chunk has the given field index.
void setIndex(CGBlockInfo &info, unsigned index) {
if (!Capture)
info.CXXThisIndex = index;
else
info.Captures[Capture->getVariable()]
= CGBlockInfo::Capture::makeIndex(index);
}
};
/// Order by descending alignment.
bool operator<(const BlockLayoutChunk &left, const BlockLayoutChunk &right) {
return left.Alignment > right.Alignment;
}
}
/// Determines if the given record type has a mutable field.
static bool hasMutableField(const CXXRecordDecl *record) {
for (CXXRecordDecl::field_iterator
i = record->field_begin(), e = record->field_end(); i != e; ++i)
if ((*i)->isMutable())
return true;
for (CXXRecordDecl::base_class_const_iterator
i = record->bases_begin(), e = record->bases_end(); i != e; ++i) {
const RecordType *record = i->getType()->castAs<RecordType>();
if (hasMutableField(cast<CXXRecordDecl>(record->getDecl())))
return true;
}
return false;
}
/// 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 CXXRecordDecl *record = cast<CXXRecordDecl>(recordType->getDecl());
// Maintain semantics for classes with non-trivial dtors or copy ctors.
if (!record->hasTrivialDestructor()) return false;
if (!record->hasTrivialCopyConstructor()) return false;
// Otherwise, we just have to make sure there aren't any mutable
// fields that might have changed since initialization.
return !hasMutableField(record);
}
/// 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,
const VarDecl *var) {
QualType type = var->getType();
// We can only do this if the variable is const.
if (!type.isConstQualified()) return 0;
// 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.getLangOptions().CPlusPlus && !isSafeForCXXConstantCapture(type))
return 0;
// 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 0;
return CGM.EmitConstantExpr(init, var->getType());
}
/// 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,
std::vector<const llvm::Type*> &elementTypes) {
ASTContext &C = CGM.getContext();
// The header is basically a 'struct { void *; int; int; void *; void *; }'.
CharUnits ptrSize, ptrAlign, intSize, intAlign;
llvm::tie(ptrSize, ptrAlign) = C.getTypeInfoInChars(C.VoidPtrTy);
llvm::tie(intSize, intAlign) = C.getTypeInfoInChars(C.IntTy);
// Are there crazy embedded platforms where this isn't true?
assert(intSize <= ptrSize && "layout assumptions horribly violated");
CharUnits headerSize = ptrSize;
if (2 * intSize < ptrAlign) headerSize += ptrSize;
else headerSize += 2 * intSize;
headerSize += 2 * ptrSize;
info.BlockAlign = ptrAlign;
info.BlockSize = headerSize;
assert(elementTypes.empty());
const llvm::Type *i8p = CGM.getTypes().ConvertType(C.VoidPtrTy);
const llvm::Type *intTy = CGM.getTypes().ConvertType(C.IntTy);
elementTypes.push_back(i8p);
elementTypes.push_back(intTy);
elementTypes.push_back(intTy);
elementTypes.push_back(i8p);
elementTypes.push_back(CGM.getBlockDescriptorType());
assert(elementTypes.size() == BlockHeaderSize);
}
/// Compute the layout of the given block. Attempts to lay the block
/// out with minimal space requirements.
static void computeBlockInfo(CodeGenModule &CGM, CGBlockInfo &info) {
ASTContext &C = CGM.getContext();
const BlockDecl *block = info.getBlockDecl();
std::vector<const llvm::Type*> elementTypes;
initializeForBlockHeader(CGM, info, elementTypes);
if (!block->hasCaptures()) {
info.StructureType =
llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true);
info.CanBeGlobal = true;
return;
}
// Collect the layout chunks.
llvm::SmallVector<BlockLayoutChunk, 16> layout;
layout.reserve(block->capturesCXXThis() +
(block->capture_end() - block->capture_begin()));
CharUnits maxFieldAlign;
// First, 'this'.
if (block->capturesCXXThis()) {
const DeclContext *DC = block->getDeclContext();
for (; isa<BlockDecl>(DC); DC = cast<BlockDecl>(DC)->getDeclContext())
;
QualType thisType = cast<CXXMethodDecl>(DC)->getThisType(C);
const 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, 0, llvmType));
}
// Next, all the block captures.
for (BlockDecl::capture_const_iterator ci = block->capture_begin(),
ce = block->capture_end(); ci != ce; ++ci) {
const VarDecl *variable = ci->getVariable();
if (ci->isByRef()) {
// We have to copy/dispose of the __block reference.
info.NeedsCopyDispose = true;
// Just use void* instead of a pointer to the byref type.
QualType byRefPtrTy = C.VoidPtrTy;
const llvm::Type *llvmType = CGM.getTypes().ConvertType(byRefPtrTy);
std::pair<CharUnits,CharUnits> tinfo
= CGM.getContext().getTypeInfoInChars(byRefPtrTy);
maxFieldAlign = std::max(maxFieldAlign, tinfo.second);
layout.push_back(BlockLayoutChunk(tinfo.second, tinfo.first,
&*ci, llvmType));
continue;
}
// Otherwise, build a layout chunk with the size and alignment of
// the declaration.
if (llvm::Constant *constant = tryCaptureAsConstant(CGM, variable)) {
info.Captures[variable] = CGBlockInfo::Capture::makeConstant(constant);
continue;
}
// Block pointers require copy/dispose.
if (variable->getType()->isBlockPointerType()) {
info.NeedsCopyDispose = true;
// So do Objective-C pointers.
} else if (variable->getType()->isObjCObjectPointerType() ||
C.isObjCNSObjectType(variable->getType())) {
info.NeedsCopyDispose = true;
// So do types that require non-trivial copy construction.
} else if (ci->hasCopyExpr()) {
info.NeedsCopyDispose = true;
info.HasCXXObject = true;
// And so do types with destructors.
} else if (CGM.getLangOptions().CPlusPlus) {
if (const CXXRecordDecl *record =
variable->getType()->getAsCXXRecordDecl()) {
if (!record->hasTrivialDestructor()) {
info.HasCXXObject = true;
info.NeedsCopyDispose = true;
}
}
}
CharUnits size = C.getTypeSizeInChars(variable->getType());
CharUnits align = C.getDeclAlign(variable);
maxFieldAlign = std::max(maxFieldAlign, align);
const llvm::Type *llvmType =
CGM.getTypes().ConvertTypeForMem(variable->getType());
layout.push_back(BlockLayoutChunk(align, size, &*ci, llvmType));
}
// If that was everything, we're done here.
if (layout.empty()) {
info.StructureType =
llvm::StructType::get(CGM.getLLVMContext(), elementTypes, true);
info.CanBeGlobal = true;
return;
}
// Sort the layout by alignment. We have to use a stable sort here
// to get reproducible results. There should probably be an
// llvm::array_pod_stable_sort.
std::stable_sort(layout.begin(), layout.end());
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) {
llvm::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) {
llvm::SmallVectorImpl<BlockLayoutChunk>::iterator first = li;
for (; li != le; ++li) {
assert(endAlign >= li->Alignment);
li->setIndex(info, elementTypes.size());
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);
}
}
// At this point, we just have to add padding if the end align still
// isn't aligned right.
if (endAlign < maxFieldAlign) {
CharUnits padding = maxFieldAlign - endAlign;
elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty,
padding.getQuantity()));
blockSize += padding;
endAlign = getLowBit(blockSize);
assert(endAlign >= maxFieldAlign);
}
// 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 (llvm::SmallVectorImpl<BlockLayoutChunk>::iterator
li = layout.begin(), le = layout.end(); li != le; ++li) {
assert(endAlign >= li->Alignment);
li->setIndex(info, elementTypes.size());
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) {
std::string Name = CurFn->getName();
CGBlockInfo blockInfo(blockExpr, Name.c_str());
// Compute information about the layout, etc., of this block.
computeBlockInfo(CGM, blockInfo);
// Using that metadata, generate the actual block function.
llvm::Constant *blockFn
= CodeGenFunction(CGM).GenerateBlockFunction(CurGD, blockInfo,
CurFuncDecl, LocalDeclMap);
blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy);
// If there is nothing to capture, we can emit this as a global block.
if (blockInfo.CanBeGlobal)
return buildGlobalBlock(CGM, blockInfo, blockFn);
// Otherwise, we have to emit this as a local block.
llvm::Constant *isa = CGM.getNSConcreteStackBlock();
isa = llvm::ConstantExpr::getBitCast(isa, VoidPtrTy);
// Build the block descriptor.
llvm::Constant *descriptor = buildBlockDescriptor(CGM, blockInfo);
const llvm::Type *intTy = ConvertType(getContext().IntTy);
llvm::AllocaInst *blockAddr =
CreateTempAlloca(blockInfo.StructureType, "block");
blockAddr->setAlignment(blockInfo.BlockAlign.getQuantity());
// Compute the initial on-stack block flags.
BlockFlags flags = BLOCK_HAS_SIGNATURE;
if (blockInfo.NeedsCopyDispose) flags |= BLOCK_HAS_COPY_DISPOSE;
if (blockInfo.HasCXXObject) flags |= BLOCK_HAS_CXX_OBJ;
if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET;
// Initialize the block literal.
Builder.CreateStore(isa, Builder.CreateStructGEP(blockAddr, 0, "block.isa"));
Builder.CreateStore(llvm::ConstantInt::get(intTy, flags.getBitMask()),
Builder.CreateStructGEP(blockAddr, 1, "block.flags"));
Builder.CreateStore(llvm::ConstantInt::get(intTy, 0),
Builder.CreateStructGEP(blockAddr, 2, "block.reserved"));
Builder.CreateStore(blockFn, Builder.CreateStructGEP(blockAddr, 3,
"block.invoke"));
Builder.CreateStore(descriptor, Builder.CreateStructGEP(blockAddr, 4,
"block.descriptor"));
// Finally, capture all the values into the block.
const BlockDecl *blockDecl = blockInfo.getBlockDecl();
// First, 'this'.
if (blockDecl->capturesCXXThis()) {
llvm::Value *addr = Builder.CreateStructGEP(blockAddr,
blockInfo.CXXThisIndex,
"block.captured-this.addr");
Builder.CreateStore(LoadCXXThis(), addr);
}
// Next, captured variables.
for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(),
ce = blockDecl->capture_end(); ci != ce; ++ci) {
const VarDecl *variable = ci->getVariable();
const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
// Ignore constant captures.
if (capture.isConstant()) continue;
QualType type = variable->getType();
// This will be a [[type]]*, except that a byref entry will just be
// an i8**.
llvm::Value *blockField =
Builder.CreateStructGEP(blockAddr, capture.getIndex(),
"block.captured");
// Compute the address of the thing we're going to move into the
// block literal.
llvm::Value *src;
if (ci->isNested()) {
// We need to use the capture from the enclosing block.
const CGBlockInfo::Capture &enclosingCapture =
BlockInfo->getCapture(variable);
// This is a [[type]]*, except that a byref entry wil just be an i8**.
src = Builder.CreateStructGEP(LoadBlockStruct(),
enclosingCapture.getIndex(),
"block.capture.addr");
} else {
// This is a [[type]]*.
src = LocalDeclMap[variable];
}
// For byrefs, we just write the pointer to the byref struct into
// the block field. There's no need to chase the forwarding
// pointer at this point, since we're building something that will
// live a shorter life than the stack byref anyway.
if (ci->isByRef()) {
// Get a void* that points to the byref struct.
if (ci->isNested())
src = Builder.CreateLoad(src, "byref.capture");
else
src = Builder.CreateBitCast(src, VoidPtrTy);
// Write that void* into the capture field.
Builder.CreateStore(src, blockField);
// If we have a copy constructor, evaluate that into the block field.
} else if (const Expr *copyExpr = ci->getCopyExpr()) {
EmitSynthesizedCXXCopyCtor(blockField, src, copyExpr);
// If it's a reference variable, copy the reference into the block field.
} else if (type->isReferenceType()) {
Builder.CreateStore(Builder.CreateLoad(src, "ref.val"), blockField);
// Otherwise, fake up a POD copy into the block field.
} else {
// We use one of these or the other depending on whether the
// reference is nested.
DeclRefExpr notNested(const_cast<VarDecl*>(variable), type, VK_LValue,
SourceLocation());
BlockDeclRefExpr nested(const_cast<VarDecl*>(variable), type,
VK_LValue, SourceLocation(), /*byref*/ false);
Expr *declRef =
(ci->isNested() ? static_cast<Expr*>(&nested) : &notNested);
ImplicitCastExpr l2r(ImplicitCastExpr::OnStack, type, CK_LValueToRValue,
declRef, VK_RValue);
EmitExprAsInit(&l2r, variable, blockField,
getContext().getDeclAlign(variable),
/*captured by init*/ false);
}
// Push a destructor if necessary. The semantics for when this
// actually gets run are really obscure.
if (!ci->isByRef() && CGM.getLangOptions().CPlusPlus)
PushDestructorCleanup(type, blockField);
}
// Cast to the converted block-pointer type, which happens (somewhat
// unfortunately) to be a pointer to function type.
llvm::Value *result =
Builder.CreateBitCast(blockAddr,
ConvertType(blockInfo.getBlockExpr()->getType()));
return result;
}
const llvm::Type *CodeGenModule::getBlockDescriptorType() {
if (BlockDescriptorType)
return BlockDescriptorType;
const 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::get(UnsignedLongTy->getContext(),
UnsignedLongTy,
UnsignedLongTy,
NULL);
getModule().addTypeName("struct.__block_descriptor",
BlockDescriptorType);
// Now form a pointer to that.
BlockDescriptorType = llvm::PointerType::getUnqual(BlockDescriptorType);
return BlockDescriptorType;
}
const llvm::Type *CodeGenModule::getGenericBlockLiteralType() {
if (GenericBlockLiteralType)
return GenericBlockLiteralType;
const llvm::Type *BlockDescPtrTy = getBlockDescriptorType();
// struct __block_literal_generic {
// void *__isa;
// int __flags;
// int __reserved;
// void (*__invoke)(void *);
// struct __block_descriptor *__descriptor;
// };
GenericBlockLiteralType = llvm::StructType::get(getLLVMContext(),
VoidPtrTy,
IntTy,
IntTy,
VoidPtrTy,
BlockDescPtrTy,
NULL);
getModule().addTypeName("struct.__block_literal_generic",
GenericBlockLiteralType);
return GenericBlockLiteralType;
}
RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr* E,
ReturnValueSlot ReturnValue) {
const BlockPointerType *BPT =
E->getCallee()->getType()->getAs<BlockPointerType>();
llvm::Value *Callee = EmitScalarExpr(E->getCallee());
// Get a pointer to the generic block literal.
const llvm::Type *BlockLiteralTy =
llvm::PointerType::getUnqual(CGM.getGenericBlockLiteralType());
// Bitcast the callee to a block literal.
llvm::Value *BlockLiteral =
Builder.CreateBitCast(Callee, BlockLiteralTy, "block.literal");
// Get the function pointer from the literal.
llvm::Value *FuncPtr = Builder.CreateStructGEP(BlockLiteral, 3, "tmp");
BlockLiteral = Builder.CreateBitCast(BlockLiteral, VoidPtrTy, "tmp");
// Add the block literal.
QualType VoidPtrTy = getContext().getPointerType(getContext().VoidTy);
CallArgList Args;
Args.push_back(std::make_pair(RValue::get(BlockLiteral), VoidPtrTy));
QualType FnType = BPT->getPointeeType();
// And the rest of the arguments.
EmitCallArgs(Args, FnType->getAs<FunctionProtoType>(),
E->arg_begin(), E->arg_end());
// Load the function.
llvm::Value *Func = Builder.CreateLoad(FuncPtr, "tmp");
const FunctionType *FuncTy = FnType->castAs<FunctionType>();
QualType ResultType = FuncTy->getResultType();
const CGFunctionInfo &FnInfo =
CGM.getTypes().getFunctionInfo(ResultType, Args,
FuncTy->getExtInfo());
// Cast the function pointer to the right type.
const llvm::Type *BlockFTy =
CGM.getTypes().GetFunctionType(FnInfo, false);
const llvm::Type *BlockFTyPtr = llvm::PointerType::getUnqual(BlockFTy);
Func = Builder.CreateBitCast(Func, BlockFTyPtr);
// And call the block.
return EmitCall(FnInfo, Func, ReturnValue, Args);
}
llvm::Value *CodeGenFunction::GetAddrOfBlockDecl(const VarDecl *variable,
bool isByRef) {
assert(BlockInfo && "evaluating block ref without block information?");
const CGBlockInfo::Capture &capture = BlockInfo->getCapture(variable);
// Handle constant captures.
if (capture.isConstant()) return LocalDeclMap[variable];
llvm::Value *addr =
Builder.CreateStructGEP(LoadBlockStruct(), capture.getIndex(),
"block.capture.addr");
if (isByRef) {
// addr should be a void** right now. Load, then cast the result
// to byref*.
addr = Builder.CreateLoad(addr);
const llvm::PointerType *byrefPointerType
= llvm::PointerType::get(BuildByRefType(variable), 0);
addr = Builder.CreateBitCast(addr, byrefPointerType,
"byref.addr");
// Follow the forwarding pointer.
addr = Builder.CreateStructGEP(addr, 1, "byref.forwarding");
addr = Builder.CreateLoad(addr, "byref.addr.forwarded");
// Cast back to byref* and GEP over to the actual object.
addr = Builder.CreateBitCast(addr, byrefPointerType);
addr = Builder.CreateStructGEP(addr, getByRefValueLLVMField(variable),
variable->getNameAsString());
}
if (variable->getType()->isReferenceType())
addr = Builder.CreateLoad(addr, "ref.tmp");
return addr;
}
llvm::Constant *
CodeGenModule::GetAddrOfGlobalBlock(const BlockExpr *blockExpr,
const char *name) {
CGBlockInfo blockInfo(blockExpr, name);
// Compute information about the layout, etc., of this block.
computeBlockInfo(*this, blockInfo);
// Using that metadata, generate the actual block function.
llvm::Constant *blockFn;
{
llvm::DenseMap<const Decl*, llvm::Value*> LocalDeclMap;
blockFn = CodeGenFunction(*this).GenerateBlockFunction(GlobalDecl(),
blockInfo,
0, LocalDeclMap);
}
blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy);
return buildGlobalBlock(*this, blockInfo, blockFn);
}
static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
const CGBlockInfo &blockInfo,
llvm::Constant *blockFn) {
assert(blockInfo.CanBeGlobal);
// Generate the constants for the block literal initializer.
llvm::Constant *fields[BlockHeaderSize];
// isa
fields[0] = CGM.getNSConcreteGlobalBlock();
// __flags
BlockFlags flags = BLOCK_IS_GLOBAL | BLOCK_HAS_SIGNATURE;
if (blockInfo.UsesStret) flags |= BLOCK_USE_STRET;
fields[1] = llvm::ConstantInt::get(CGM.IntTy, flags.getBitMask());
// Reserved
fields[2] = llvm::Constant::getNullValue(CGM.IntTy);
// Function
fields[3] = blockFn;
// Descriptor
fields[4] = buildBlockDescriptor(CGM, blockInfo);
llvm::Constant *init =
llvm::ConstantStruct::get(CGM.getLLVMContext(), fields, BlockHeaderSize,
/*packed*/ false);
llvm::GlobalVariable *literal =
new llvm::GlobalVariable(CGM.getModule(),
init->getType(),
/*constant*/ true,
llvm::GlobalVariable::InternalLinkage,
init,
"__block_literal_global");
literal->setAlignment(blockInfo.BlockAlign.getQuantity());
// Return a constant of the appropriately-casted type.
const llvm::Type *requiredType =
CGM.getTypes().ConvertType(blockInfo.getBlockExpr()->getType());
return llvm::ConstantExpr::getBitCast(literal, requiredType);
}
llvm::Function *
CodeGenFunction::GenerateBlockFunction(GlobalDecl GD,
const CGBlockInfo &blockInfo,
const Decl *outerFnDecl,
const DeclMapTy &ldm) {
const BlockDecl *blockDecl = blockInfo.getBlockDecl();
// Check if we should generate debug info for this block function.
if (CGM.getModuleDebugInfo())
DebugInfo = CGM.getModuleDebugInfo();
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 VarDecl *var = dyn_cast<VarDecl>(i->first);
if (var && !var->hasLocalStorage())
LocalDeclMap[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;
IdentifierInfo *II = &CGM.getContext().Idents.get(".block_descriptor");
ImplicitParamDecl selfDecl(const_cast<BlockDecl*>(blockDecl),
SourceLocation(), II, selfTy);
args.push_back(&selfDecl);
// Now add the rest of the parameters.
for (BlockDecl::param_const_iterator i = blockDecl->param_begin(),
e = blockDecl->param_end(); i != e; ++i)
args.push_back(*i);
// Create the function declaration.
const FunctionProtoType *fnType =
cast<FunctionProtoType>(blockInfo.getBlockExpr()->getFunctionType());
const CGFunctionInfo &fnInfo =
CGM.getTypes().getFunctionInfo(fnType->getResultType(), args,
fnType->getExtInfo());
if (CGM.ReturnTypeUsesSRet(fnInfo))
blockInfo.UsesStret = true;
const llvm::FunctionType *fnLLVMType =
CGM.getTypes().GetFunctionType(fnInfo, fnType->isVariadic());
MangleBuffer name;
CGM.getBlockMangledName(GD, name, blockDecl);
llvm::Function *fn =
llvm::Function::Create(fnLLVMType, llvm::GlobalValue::InternalLinkage,
name.getString(), &CGM.getModule());
CGM.SetInternalFunctionAttributes(blockDecl, fn, fnInfo);
// Begin generating the function.
StartFunction(blockDecl, fnType->getResultType(), fn, fnInfo, args,
blockInfo.getBlockExpr()->getBody()->getLocEnd());
CurFuncDecl = outerFnDecl; // StartFunction sets this to blockDecl
// Okay. Undo some of what StartFunction did.
// Pull the 'self' reference out of the local decl map.
llvm::Value *blockAddr = LocalDeclMap[&selfDecl];
LocalDeclMap.erase(&selfDecl);
BlockPointer = Builder.CreateBitCast(blockAddr,
blockInfo.StructureType->getPointerTo(),
"block");
// If we have a C++ 'this' reference, go ahead and force it into
// existence now.
if (blockDecl->capturesCXXThis()) {
llvm::Value *addr = Builder.CreateStructGEP(BlockPointer,
blockInfo.CXXThisIndex,
"block.captured-this");
CXXThisValue = Builder.CreateLoad(addr, "this");
}
// LoadObjCSelf() expects there to be an entry for 'self' in LocalDeclMap;
// appease it.
if (const ObjCMethodDecl *method
= dyn_cast_or_null<ObjCMethodDecl>(CurFuncDecl)) {
const VarDecl *self = method->getSelfDecl();
// There might not be a capture for 'self', but if there is...
if (blockInfo.Captures.count(self)) {
const CGBlockInfo::Capture &capture = blockInfo.getCapture(self);
llvm::Value *selfAddr = Builder.CreateStructGEP(BlockPointer,
capture.getIndex(),
"block.captured-self");
LocalDeclMap[self] = selfAddr;
}
}
// Also force all the constant captures.
for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(),
ce = blockDecl->capture_end(); ci != ce; ++ci) {
const VarDecl *variable = ci->getVariable();
const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
if (!capture.isConstant()) continue;
unsigned align = getContext().getDeclAlign(variable).getQuantity();
llvm::AllocaInst *alloca =
CreateMemTemp(variable->getType(), "block.captured-const");
alloca->setAlignment(align);
Builder.CreateStore(capture.getConstant(), alloca, align);
LocalDeclMap[variable] = alloca;
}
// Save a spot to insert the debug information for all the BlockDeclRefDecls.
llvm::BasicBlock *entry = Builder.GetInsertBlock();
llvm::BasicBlock::iterator entry_ptr = Builder.GetInsertPoint();
--entry_ptr;
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 BlockDeclRefDecls.
// FIXME: also for 'this'
if (CGDebugInfo *DI = getDebugInfo()) {
for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(),
ce = blockDecl->capture_end(); ci != ce; ++ci) {
const VarDecl *variable = ci->getVariable();
DI->setLocation(variable->getLocation());
const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
if (capture.isConstant()) {
DI->EmitDeclareOfAutoVariable(variable, LocalDeclMap[variable],
Builder);
continue;
}
DI->EmitDeclareOfBlockDeclRefVariable(variable, BlockPointer,
Builder, blockInfo);
}
}
// And resume where we left off.
if (resume == 0)
Builder.ClearInsertionPoint();
else
Builder.SetInsertPoint(resume);
FinishFunction(cast<CompoundStmt>(blockDecl->getBody())->getRBracLoc());
return fn;
}
/*
notes.push_back(HelperInfo());
HelperInfo &note = notes.back();
note.index = capture.getIndex();
note.RequiresCopying = (ci->hasCopyExpr() || BlockRequiresCopying(type));
note.cxxbar_import = ci->getCopyExpr();
if (ci->isByRef()) {
note.flag = BLOCK_FIELD_IS_BYREF;
if (type.isObjCGCWeak())
note.flag |= BLOCK_FIELD_IS_WEAK;
} else if (type->isBlockPointerType()) {
note.flag = BLOCK_FIELD_IS_BLOCK;
} else {
note.flag = BLOCK_FIELD_IS_OBJECT;
}
*/
llvm::Constant *
CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) {
ASTContext &C = getContext();
FunctionArgList args;
ImplicitParamDecl dstDecl(0, SourceLocation(), 0, C.VoidPtrTy);
args.push_back(&dstDecl);
ImplicitParamDecl srcDecl(0, SourceLocation(), 0, C.VoidPtrTy);
args.push_back(&srcDecl);
const CGFunctionInfo &FI =
CGM.getTypes().getFunctionInfo(C.VoidTy, args, FunctionType::ExtInfo());
// FIXME: it would be nice if these were mergeable with things with
// identical semantics.
const llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI, false);
llvm::Function *Fn =
llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
"__copy_helper_block_", &CGM.getModule());
IdentifierInfo *II
= &CGM.getContext().Idents.get("__copy_helper_block_");
FunctionDecl *FD = FunctionDecl::Create(C,
C.getTranslationUnitDecl(),
SourceLocation(),
SourceLocation(), II, C.VoidTy, 0,
SC_Static,
SC_None,
false,
true);
StartFunction(FD, C.VoidTy, Fn, FI, args, SourceLocation());
const llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
llvm::Value *src = GetAddrOfLocalVar(&srcDecl);
src = Builder.CreateLoad(src);
src = Builder.CreateBitCast(src, structPtrTy, "block.source");
llvm::Value *dst = GetAddrOfLocalVar(&dstDecl);
dst = Builder.CreateLoad(dst);
dst = Builder.CreateBitCast(dst, structPtrTy, "block.dest");
const BlockDecl *blockDecl = blockInfo.getBlockDecl();
for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(),
ce = blockDecl->capture_end(); ci != ce; ++ci) {
const VarDecl *variable = ci->getVariable();
QualType type = variable->getType();
const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
if (capture.isConstant()) continue;
const Expr *copyExpr = ci->getCopyExpr();
unsigned flags = 0;
if (copyExpr) {
assert(!ci->isByRef());
// don't bother computing flags
} else if (ci->isByRef()) {
flags = BLOCK_FIELD_IS_BYREF;
if (type.isObjCGCWeak()) flags |= BLOCK_FIELD_IS_WEAK;
} else if (type->isBlockPointerType()) {
flags = BLOCK_FIELD_IS_BLOCK;
} else if (type->isObjCObjectPointerType() || C.isObjCNSObjectType(type)) {
flags = BLOCK_FIELD_IS_OBJECT;
}
if (!copyExpr && !flags) continue;
unsigned index = capture.getIndex();
llvm::Value *srcField = Builder.CreateStructGEP(src, index);
llvm::Value *dstField = Builder.CreateStructGEP(dst, index);
// If there's an explicit copy expression, we do that.
if (copyExpr) {
EmitSynthesizedCXXCopyCtor(dstField, srcField, copyExpr);
} else {
llvm::Value *srcValue = Builder.CreateLoad(srcField, "blockcopy.src");
srcValue = Builder.CreateBitCast(srcValue, VoidPtrTy);
llvm::Value *dstAddr = Builder.CreateBitCast(dstField, VoidPtrTy);
Builder.CreateCall3(CGM.getBlockObjectAssign(), dstAddr, srcValue,
llvm::ConstantInt::get(Int32Ty, flags));
}
}
FinishFunction();
return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
}
llvm::Constant *
CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) {
ASTContext &C = getContext();
FunctionArgList args;
ImplicitParamDecl srcDecl(0, SourceLocation(), 0, C.VoidPtrTy);
args.push_back(&srcDecl);
const CGFunctionInfo &FI =
CGM.getTypes().getFunctionInfo(C.VoidTy, args, FunctionType::ExtInfo());
// FIXME: We'd like to put these into a mergable by content, with
// internal linkage.
const llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI, false);
llvm::Function *Fn =
llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
"__destroy_helper_block_", &CGM.getModule());
IdentifierInfo *II
= &CGM.getContext().Idents.get("__destroy_helper_block_");
FunctionDecl *FD = FunctionDecl::Create(C, C.getTranslationUnitDecl(),
SourceLocation(),
SourceLocation(), II, C.VoidTy, 0,
SC_Static,
SC_None,
false, true);
StartFunction(FD, C.VoidTy, Fn, FI, args, SourceLocation());
const llvm::Type *structPtrTy = blockInfo.StructureType->getPointerTo();
llvm::Value *src = GetAddrOfLocalVar(&srcDecl);
src = Builder.CreateLoad(src);
src = Builder.CreateBitCast(src, structPtrTy, "block");
const BlockDecl *blockDecl = blockInfo.getBlockDecl();
CodeGenFunction::RunCleanupsScope cleanups(*this);
for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(),
ce = blockDecl->capture_end(); ci != ce; ++ci) {
const VarDecl *variable = ci->getVariable();
QualType type = variable->getType();
const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
if (capture.isConstant()) continue;
BlockFieldFlags flags;
const CXXDestructorDecl *dtor = 0;
if (ci->isByRef()) {
flags = BLOCK_FIELD_IS_BYREF;
if (type.isObjCGCWeak()) flags |= BLOCK_FIELD_IS_WEAK;
} else if (type->isBlockPointerType()) {
flags = BLOCK_FIELD_IS_BLOCK;
} else if (type->isObjCObjectPointerType() || C.isObjCNSObjectType(type)) {
flags = BLOCK_FIELD_IS_OBJECT;
} else if (C.getLangOptions().CPlusPlus) {
if (const CXXRecordDecl *record = type->getAsCXXRecordDecl())
if (!record->hasTrivialDestructor())
dtor = record->getDestructor();
}
if (!dtor && flags.empty()) continue;
unsigned index = capture.getIndex();
llvm::Value *srcField = Builder.CreateStructGEP(src, index);
// If there's an explicit copy expression, we do that.
if (dtor) {
PushDestructorCleanup(dtor, srcField);
// Otherwise we call _Block_object_dispose. It wouldn't be too
// hard to just emit this as a cleanup if we wanted to make sure
// that things were done in reverse.
} else {
llvm::Value *value = Builder.CreateLoad(srcField);
value = Builder.CreateBitCast(value, VoidPtrTy);
BuildBlockRelease(value, flags);
}
}
cleanups.ForceCleanup();
FinishFunction();
return llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
}
llvm::Constant *CodeGenFunction::
GeneratebyrefCopyHelperFunction(const llvm::Type *T, BlockFieldFlags flags,
const VarDecl *variable) {
QualType R = getContext().VoidTy;
FunctionArgList args;
ImplicitParamDecl dst(0, SourceLocation(), 0, getContext().VoidPtrTy);
args.push_back(&dst);
ImplicitParamDecl src(0, SourceLocation(), 0, getContext().VoidPtrTy);
args.push_back(&src);
const CGFunctionInfo &FI =
CGM.getTypes().getFunctionInfo(R, args, FunctionType::ExtInfo());
CodeGenTypes &Types = CGM.getTypes();
const llvm::FunctionType *LTy = Types.GetFunctionType(FI, false);
// 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_", &CGM.getModule());
IdentifierInfo *II
= &CGM.getContext().Idents.get("__Block_byref_object_copy_");
FunctionDecl *FD = FunctionDecl::Create(getContext(),
getContext().getTranslationUnitDecl(),
SourceLocation(),
SourceLocation(), II, R, 0,
SC_Static,
SC_None,
false, true);
StartFunction(FD, R, Fn, FI, args, SourceLocation());
// dst->x
llvm::Value *V = GetAddrOfLocalVar(&dst);
V = Builder.CreateBitCast(V, llvm::PointerType::get(T, 0));
V = Builder.CreateLoad(V);
V = Builder.CreateStructGEP(V, 6, "x");
llvm::Value *DstObj = V;
// src->x
V = GetAddrOfLocalVar(&src);
V = Builder.CreateLoad(V);
V = Builder.CreateBitCast(V, T);
V = Builder.CreateStructGEP(V, 6, "x");
if (Expr *copyExpr = getContext().getBlockVarCopyInits(variable)) {
llvm::Value *SrcObj = V;
EmitSynthesizedCXXCopyCtor(DstObj, SrcObj, copyExpr);
} else {
DstObj = Builder.CreateBitCast(DstObj, VoidPtrTy);
V = Builder.CreateBitCast(V, VoidPtrPtrTy);
llvm::Value *SrcObj = Builder.CreateLoad(V);
flags |= BLOCK_BYREF_CALLER;
llvm::Value *N = llvm::ConstantInt::get(Int32Ty, flags.getBitMask());
llvm::Value *F = CGM.getBlockObjectAssign();
Builder.CreateCall3(F, DstObj, SrcObj, N);
}
FinishFunction();
return llvm::ConstantExpr::getBitCast(Fn, Int8PtrTy);
}
llvm::Constant *
CodeGenFunction::GeneratebyrefDestroyHelperFunction(const llvm::Type *T,
BlockFieldFlags flags,
const VarDecl *variable) {
QualType R = getContext().VoidTy;
FunctionArgList args;
ImplicitParamDecl src(0, SourceLocation(), 0, getContext().VoidPtrTy);
args.push_back(&src);
const CGFunctionInfo &FI =
CGM.getTypes().getFunctionInfo(R, args, FunctionType::ExtInfo());
CodeGenTypes &Types = CGM.getTypes();
const llvm::FunctionType *LTy = Types.GetFunctionType(FI, false);
// 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_",
&CGM.getModule());
IdentifierInfo *II
= &CGM.getContext().Idents.get("__Block_byref_object_dispose_");
FunctionDecl *FD = FunctionDecl::Create(getContext(),
getContext().getTranslationUnitDecl(),
SourceLocation(),
SourceLocation(), II, R, 0,
SC_Static,
SC_None,
false, true);
StartFunction(FD, R, Fn, FI, args, SourceLocation());
llvm::Value *V = GetAddrOfLocalVar(&src);
V = Builder.CreateBitCast(V, llvm::PointerType::get(T, 0));
V = Builder.CreateLoad(V);
V = Builder.CreateStructGEP(V, 6, "x");
// If it's not any kind of special object, it must have a destructor
// or something.
if (!flags.isSpecialPointer()) {
EHScopeStack::stable_iterator CleanupDepth = EHStack.stable_begin();
PushDestructorCleanup(variable->getType(), V);
PopCleanupBlocks(CleanupDepth);
// Otherwise, call _Block_object_dispose.
} else {
V = Builder.CreateBitCast(V, llvm::PointerType::get(Int8PtrTy, 0));
V = Builder.CreateLoad(V);
flags |= BLOCK_BYREF_CALLER;
BuildBlockRelease(V, flags);
}
FinishFunction();
return llvm::ConstantExpr::getBitCast(Fn, Int8PtrTy);
}
llvm::Constant *CodeGenModule::BuildbyrefCopyHelper(const llvm::Type *T,
BlockFieldFlags flags,
unsigned align,
const VarDecl *var) {
// All alignments below pointer alignment are bumped up, as we
// always have at least that much alignment to begin with.
if (align < PointerAlignInBytes) align = PointerAlignInBytes;
// As an optimization, we only generate a single function of each kind we
// might need. We need a different one for each alignment and for each
// setting of flags. We mix Align and flag to get the kind.
uint64_t Kind = (uint64_t)align*BLOCK_BYREF_CURRENT_MAX + flags.getBitMask();
llvm::Constant *&Entry = AssignCache[Kind];
if (!Entry)
Entry = CodeGenFunction(*this).
GeneratebyrefCopyHelperFunction(T, flags, var);
return Entry;
}
llvm::Constant *CodeGenModule::BuildbyrefDestroyHelper(const llvm::Type *T,
BlockFieldFlags flags,
unsigned align,
const VarDecl *var) {
// All alignments below pointer alignment are bumped up, as we
// always have at least that much alignment to begin with.
if (align < PointerAlignInBytes) align = PointerAlignInBytes;
// As an optimization, we only generate a single function of each kind we
// might need. We need a different one for each alignment and for each
// setting of flags. We mix Align and flag to get the kind.
uint64_t Kind = (uint64_t)align*BLOCK_BYREF_CURRENT_MAX + flags.getBitMask();
llvm::Constant *&Entry = DestroyCache[Kind];
if (!Entry)
Entry = CodeGenFunction(*this).
GeneratebyrefDestroyHelperFunction(T, flags, var);
return Entry;
}
void CodeGenFunction::BuildBlockRelease(llvm::Value *V, BlockFieldFlags flags) {
llvm::Value *F = CGM.getBlockObjectDispose();
llvm::Value *N;
V = Builder.CreateBitCast(V, Int8PtrTy);
N = llvm::ConstantInt::get(Int32Ty, flags.getBitMask());
Builder.CreateCall2(F, V, N);
}
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