1//===--- CGBlocks.cpp - Emit LLVM Code for declarations ---------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This contains code to emit blocks.
10//
11//===----------------------------------------------------------------------===//
12
13#include "CGBlocks.h"
14#include "CGCXXABI.h"
15#include "CGDebugInfo.h"
16#include "CGObjCRuntime.h"
17#include "CGOpenCLRuntime.h"
18#include "CodeGenFunction.h"
19#include "CodeGenModule.h"
20#include "ConstantEmitter.h"
21#include "TargetInfo.h"
22#include "clang/AST/Attr.h"
23#include "clang/AST/DeclObjC.h"
24#include "clang/CodeGen/ConstantInitBuilder.h"
25#include "llvm/ADT/SmallSet.h"
26#include "llvm/IR/DataLayout.h"
27#include "llvm/IR/Module.h"
28#include "llvm/Support/ScopedPrinter.h"
29#include <algorithm>
30#include <cstdio>
31
32using namespace clang;
33using namespace CodeGen;
34
35CGBlockInfo::CGBlockInfo(const BlockDecl *block, StringRef name)
36 : Name(name), CXXThisIndex(0), CanBeGlobal(false), NeedsCopyDispose(false),
37 NoEscape(false), HasCXXObject(false), UsesStret(false),
38 HasCapturedVariableLayout(false), CapturesNonExternalType(false),
39 LocalAddress(Address::invalid()), StructureType(nullptr), Block(block) {
40
41 // Skip asm prefix, if any. 'name' is usually taken directly from
42 // the mangled name of the enclosing function.
43 if (!name.empty() && name[0] == '\01')
44 name = name.substr(Start: 1);
45}
46
47// Anchor the vtable to this translation unit.
48BlockByrefHelpers::~BlockByrefHelpers() {}
49
50/// Build the given block as a global block.
51static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
52 const CGBlockInfo &blockInfo,
53 llvm::Constant *blockFn);
54
55/// Build the helper function to copy a block.
56static llvm::Constant *buildCopyHelper(CodeGenModule &CGM,
57 const CGBlockInfo &blockInfo) {
58 return CodeGenFunction(CGM).GenerateCopyHelperFunction(blockInfo);
59}
60
61/// Build the helper function to dispose of a block.
62static llvm::Constant *buildDisposeHelper(CodeGenModule &CGM,
63 const CGBlockInfo &blockInfo) {
64 return CodeGenFunction(CGM).GenerateDestroyHelperFunction(blockInfo);
65}
66
67namespace {
68
69enum class CaptureStrKind {
70 // String for the copy helper.
71 CopyHelper,
72 // String for the dispose helper.
73 DisposeHelper,
74 // Merge the strings for the copy helper and dispose helper.
75 Merged
76};
77
78} // end anonymous namespace
79
80static std::string getBlockCaptureStr(const CGBlockInfo::Capture &Cap,
81 CaptureStrKind StrKind,
82 CharUnits BlockAlignment,
83 CodeGenModule &CGM);
84
85static std::string getBlockDescriptorName(const CGBlockInfo &BlockInfo,
86 CodeGenModule &CGM) {
87 std::string Name = "__block_descriptor_";
88 Name += llvm::to_string(Value: BlockInfo.BlockSize.getQuantity()) + "_";
89
90 if (BlockInfo.NeedsCopyDispose) {
91 if (CGM.getLangOpts().Exceptions)
92 Name += "e";
93 if (CGM.getCodeGenOpts().ObjCAutoRefCountExceptions)
94 Name += "a";
95 Name += llvm::to_string(Value: BlockInfo.BlockAlign.getQuantity()) + "_";
96
97 for (auto &Cap : BlockInfo.SortedCaptures) {
98 if (Cap.isConstantOrTrivial())
99 continue;
100
101 Name += llvm::to_string(Value: Cap.getOffset().getQuantity());
102
103 if (Cap.CopyKind == Cap.DisposeKind) {
104 // If CopyKind and DisposeKind are the same, merge the capture
105 // information.
106 assert(Cap.CopyKind != BlockCaptureEntityKind::None &&
107 "shouldn't see BlockCaptureManagedEntity that is None");
108 Name += getBlockCaptureStr(Cap, StrKind: CaptureStrKind::Merged,
109 BlockAlignment: BlockInfo.BlockAlign, CGM);
110 } else {
111 // If CopyKind and DisposeKind are not the same, which can happen when
112 // either Kind is None or the captured object is a __strong block,
113 // concatenate the copy and dispose strings.
114 Name += getBlockCaptureStr(Cap, StrKind: CaptureStrKind::CopyHelper,
115 BlockAlignment: BlockInfo.BlockAlign, CGM);
116 Name += getBlockCaptureStr(Cap, StrKind: CaptureStrKind::DisposeHelper,
117 BlockAlignment: BlockInfo.BlockAlign, CGM);
118 }
119 }
120 Name += "_";
121 }
122
123 std::string TypeAtEncoding =
124 CGM.getContext().getObjCEncodingForBlock(blockExpr: BlockInfo.getBlockExpr());
125 /// Replace occurrences of '@' with '\1'. '@' is reserved on ELF platforms as
126 /// a separator between symbol name and symbol version.
127 std::replace(first: TypeAtEncoding.begin(), last: TypeAtEncoding.end(), old_value: '@', new_value: '\1');
128 Name += "e" + llvm::to_string(Value: TypeAtEncoding.size()) + "_" + TypeAtEncoding;
129 Name += "l" + CGM.getObjCRuntime().getRCBlockLayoutStr(CGM, blockInfo: BlockInfo);
130 return Name;
131}
132
133/// buildBlockDescriptor - Build the block descriptor meta-data for a block.
134/// buildBlockDescriptor is accessed from 5th field of the Block_literal
135/// meta-data and contains stationary information about the block literal.
136/// Its definition will have 4 (or optionally 6) words.
137/// \code
138/// struct Block_descriptor {
139/// unsigned long reserved;
140/// unsigned long size; // size of Block_literal metadata in bytes.
141/// void *copy_func_helper_decl; // optional copy helper.
142/// void *destroy_func_decl; // optional destructor helper.
143/// void *block_method_encoding_address; // @encode for block literal signature.
144/// void *block_layout_info; // encoding of captured block variables.
145/// };
146/// \endcode
147static llvm::Constant *buildBlockDescriptor(CodeGenModule &CGM,
148 const CGBlockInfo &blockInfo) {
149 ASTContext &C = CGM.getContext();
150
151 llvm::IntegerType *ulong =
152 cast<llvm::IntegerType>(CGM.getTypes().ConvertType(T: C.UnsignedLongTy));
153 llvm::PointerType *i8p = nullptr;
154 if (CGM.getLangOpts().OpenCL)
155 i8p = llvm::PointerType::get(
156 C&: CGM.getLLVMContext(), AddressSpace: C.getTargetAddressSpace(AS: LangAS::opencl_constant));
157 else
158 i8p = CGM.VoidPtrTy;
159
160 std::string descName;
161
162 // If an equivalent block descriptor global variable exists, return it.
163 if (C.getLangOpts().ObjC &&
164 CGM.getLangOpts().getGC() == LangOptions::NonGC) {
165 descName = getBlockDescriptorName(BlockInfo: blockInfo, CGM);
166 if (llvm::GlobalValue *desc = CGM.getModule().getNamedValue(Name: descName))
167 return desc;
168 }
169
170 // If there isn't an equivalent block descriptor global variable, create a new
171 // one.
172 ConstantInitBuilder builder(CGM);
173 auto elements = builder.beginStruct();
174
175 // reserved
176 elements.addInt(intTy: ulong, value: 0);
177
178 // Size
179 // FIXME: What is the right way to say this doesn't fit? We should give
180 // a user diagnostic in that case. Better fix would be to change the
181 // API to size_t.
182 elements.addInt(intTy: ulong, value: blockInfo.BlockSize.getQuantity());
183
184 // Optional copy/dispose helpers.
185 bool hasInternalHelper = false;
186 if (blockInfo.NeedsCopyDispose) {
187 // copy_func_helper_decl
188 llvm::Constant *copyHelper = buildCopyHelper(CGM, blockInfo);
189 elements.add(value: copyHelper);
190
191 // destroy_func_decl
192 llvm::Constant *disposeHelper = buildDisposeHelper(CGM, blockInfo);
193 elements.add(value: disposeHelper);
194
195 if (cast<llvm::Function>(Val: copyHelper->stripPointerCasts())
196 ->hasInternalLinkage() ||
197 cast<llvm::Function>(Val: disposeHelper->stripPointerCasts())
198 ->hasInternalLinkage())
199 hasInternalHelper = true;
200 }
201
202 // Signature. Mandatory ObjC-style method descriptor @encode sequence.
203 std::string typeAtEncoding =
204 CGM.getContext().getObjCEncodingForBlock(blockExpr: blockInfo.getBlockExpr());
205 elements.add(value: CGM.GetAddrOfConstantCString(Str: typeAtEncoding).getPointer());
206
207 // GC layout.
208 if (C.getLangOpts().ObjC) {
209 if (CGM.getLangOpts().getGC() != LangOptions::NonGC)
210 elements.add(value: CGM.getObjCRuntime().BuildGCBlockLayout(CGM, blockInfo));
211 else
212 elements.add(value: CGM.getObjCRuntime().BuildRCBlockLayout(CGM, blockInfo));
213 }
214 else
215 elements.addNullPointer(ptrTy: i8p);
216
217 unsigned AddrSpace = 0;
218 if (C.getLangOpts().OpenCL)
219 AddrSpace = C.getTargetAddressSpace(AS: LangAS::opencl_constant);
220
221 llvm::GlobalValue::LinkageTypes linkage;
222 if (descName.empty()) {
223 linkage = llvm::GlobalValue::InternalLinkage;
224 descName = "__block_descriptor_tmp";
225 } else if (hasInternalHelper) {
226 // If either the copy helper or the dispose helper has internal linkage,
227 // the block descriptor must have internal linkage too.
228 linkage = llvm::GlobalValue::InternalLinkage;
229 } else {
230 linkage = llvm::GlobalValue::LinkOnceODRLinkage;
231 }
232
233 llvm::GlobalVariable *global =
234 elements.finishAndCreateGlobal(descName, CGM.getPointerAlign(),
235 /*constant*/ true, linkage, AddrSpace);
236
237 if (linkage == llvm::GlobalValue::LinkOnceODRLinkage) {
238 if (CGM.supportsCOMDAT())
239 global->setComdat(CGM.getModule().getOrInsertComdat(Name: descName));
240 global->setVisibility(llvm::GlobalValue::HiddenVisibility);
241 global->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
242 }
243
244 return global;
245}
246
247/*
248 Purely notional variadic template describing the layout of a block.
249
250 template <class _ResultType, class... _ParamTypes, class... _CaptureTypes>
251 struct Block_literal {
252 /// Initialized to one of:
253 /// extern void *_NSConcreteStackBlock[];
254 /// extern void *_NSConcreteGlobalBlock[];
255 ///
256 /// In theory, we could start one off malloc'ed by setting
257 /// BLOCK_NEEDS_FREE, giving it a refcount of 1, and using
258 /// this isa:
259 /// extern void *_NSConcreteMallocBlock[];
260 struct objc_class *isa;
261
262 /// These are the flags (with corresponding bit number) that the
263 /// compiler is actually supposed to know about.
264 /// 23. BLOCK_IS_NOESCAPE - indicates that the block is non-escaping
265 /// 25. BLOCK_HAS_COPY_DISPOSE - indicates that the block
266 /// descriptor provides copy and dispose helper functions
267 /// 26. BLOCK_HAS_CXX_OBJ - indicates that there's a captured
268 /// object with a nontrivial destructor or copy constructor
269 /// 28. BLOCK_IS_GLOBAL - indicates that the block is allocated
270 /// as global memory
271 /// 29. BLOCK_USE_STRET - indicates that the block function
272 /// uses stret, which objc_msgSend needs to know about
273 /// 30. BLOCK_HAS_SIGNATURE - indicates that the block has an
274 /// @encoded signature string
275 /// And we're not supposed to manipulate these:
276 /// 24. BLOCK_NEEDS_FREE - indicates that the block has been moved
277 /// to malloc'ed memory
278 /// 27. BLOCK_IS_GC - indicates that the block has been moved to
279 /// to GC-allocated memory
280 /// Additionally, the bottom 16 bits are a reference count which
281 /// should be zero on the stack.
282 int flags;
283
284 /// Reserved; should be zero-initialized.
285 int reserved;
286
287 /// Function pointer generated from block literal.
288 _ResultType (*invoke)(Block_literal *, _ParamTypes...);
289
290 /// Block description metadata generated from block literal.
291 struct Block_descriptor *block_descriptor;
292
293 /// Captured values follow.
294 _CapturesTypes captures...;
295 };
296 */
297
298namespace {
299 /// A chunk of data that we actually have to capture in the block.
300 struct BlockLayoutChunk {
301 CharUnits Alignment;
302 CharUnits Size;
303 const BlockDecl::Capture *Capture; // null for 'this'
304 llvm::Type *Type;
305 QualType FieldType;
306 BlockCaptureEntityKind CopyKind, DisposeKind;
307 BlockFieldFlags CopyFlags, DisposeFlags;
308
309 BlockLayoutChunk(CharUnits align, CharUnits size,
310 const BlockDecl::Capture *capture, llvm::Type *type,
311 QualType fieldType, BlockCaptureEntityKind CopyKind,
312 BlockFieldFlags CopyFlags,
313 BlockCaptureEntityKind DisposeKind,
314 BlockFieldFlags DisposeFlags)
315 : Alignment(align), Size(size), Capture(capture), Type(type),
316 FieldType(fieldType), CopyKind(CopyKind), DisposeKind(DisposeKind),
317 CopyFlags(CopyFlags), DisposeFlags(DisposeFlags) {}
318
319 /// Tell the block info that this chunk has the given field index.
320 void setIndex(CGBlockInfo &info, unsigned index, CharUnits offset) {
321 if (!Capture) {
322 info.CXXThisIndex = index;
323 info.CXXThisOffset = offset;
324 } else {
325 info.SortedCaptures.push_back(CGBlockInfo::Capture::makeIndex(
326 index, offset, FieldType, CopyKind, CopyFlags, DisposeKind,
327 DisposeFlags, Capture));
328 }
329 }
330
331 bool isTrivial() const {
332 return CopyKind == BlockCaptureEntityKind::None &&
333 DisposeKind == BlockCaptureEntityKind::None;
334 }
335 };
336
337 /// Order by 1) all __strong together 2) next, all block together 3) next,
338 /// all byref together 4) next, all __weak together. Preserve descending
339 /// alignment in all situations.
340 bool operator<(const BlockLayoutChunk &left, const BlockLayoutChunk &right) {
341 if (left.Alignment != right.Alignment)
342 return left.Alignment > right.Alignment;
343
344 auto getPrefOrder = [](const BlockLayoutChunk &chunk) {
345 switch (chunk.CopyKind) {
346 case BlockCaptureEntityKind::ARCStrong:
347 return 0;
348 case BlockCaptureEntityKind::BlockObject:
349 switch (chunk.CopyFlags.getBitMask()) {
350 case BLOCK_FIELD_IS_OBJECT:
351 return 0;
352 case BLOCK_FIELD_IS_BLOCK:
353 return 1;
354 case BLOCK_FIELD_IS_BYREF:
355 return 2;
356 default:
357 break;
358 }
359 break;
360 case BlockCaptureEntityKind::ARCWeak:
361 return 3;
362 default:
363 break;
364 }
365 return 4;
366 };
367
368 return getPrefOrder(left) < getPrefOrder(right);
369 }
370} // end anonymous namespace
371
372static std::pair<BlockCaptureEntityKind, BlockFieldFlags>
373computeCopyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T,
374 const LangOptions &LangOpts);
375
376static std::pair<BlockCaptureEntityKind, BlockFieldFlags>
377computeDestroyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T,
378 const LangOptions &LangOpts);
379
380static void addBlockLayout(CharUnits align, CharUnits size,
381 const BlockDecl::Capture *capture, llvm::Type *type,
382 QualType fieldType,
383 SmallVectorImpl<BlockLayoutChunk> &Layout,
384 CGBlockInfo &Info, CodeGenModule &CGM) {
385 if (!capture) {
386 // 'this' capture.
387 Layout.push_back(Elt: BlockLayoutChunk(
388 align, size, capture, type, fieldType, BlockCaptureEntityKind::None,
389 BlockFieldFlags(), BlockCaptureEntityKind::None, BlockFieldFlags()));
390 return;
391 }
392
393 const LangOptions &LangOpts = CGM.getLangOpts();
394 BlockCaptureEntityKind CopyKind, DisposeKind;
395 BlockFieldFlags CopyFlags, DisposeFlags;
396
397 std::tie(args&: CopyKind, args&: CopyFlags) =
398 computeCopyInfoForBlockCapture(CI: *capture, T: fieldType, LangOpts);
399 std::tie(args&: DisposeKind, args&: DisposeFlags) =
400 computeDestroyInfoForBlockCapture(CI: *capture, T: fieldType, LangOpts);
401 Layout.push_back(Elt: BlockLayoutChunk(align, size, capture, type, fieldType,
402 CopyKind, CopyFlags, DisposeKind,
403 DisposeFlags));
404
405 if (Info.NoEscape)
406 return;
407
408 if (!Layout.back().isTrivial())
409 Info.NeedsCopyDispose = true;
410}
411
412/// Determines if the given type is safe for constant capture in C++.
413static bool isSafeForCXXConstantCapture(QualType type) {
414 const RecordType *recordType =
415 type->getBaseElementTypeUnsafe()->getAs<RecordType>();
416
417 // Only records can be unsafe.
418 if (!recordType) return true;
419
420 const auto *record = cast<CXXRecordDecl>(Val: recordType->getDecl());
421
422 // Maintain semantics for classes with non-trivial dtors or copy ctors.
423 if (!record->hasTrivialDestructor()) return false;
424 if (record->hasNonTrivialCopyConstructor()) return false;
425
426 // Otherwise, we just have to make sure there aren't any mutable
427 // fields that might have changed since initialization.
428 return !record->hasMutableFields();
429}
430
431/// It is illegal to modify a const object after initialization.
432/// Therefore, if a const object has a constant initializer, we don't
433/// actually need to keep storage for it in the block; we'll just
434/// rematerialize it at the start of the block function. This is
435/// acceptable because we make no promises about address stability of
436/// captured variables.
437static llvm::Constant *tryCaptureAsConstant(CodeGenModule &CGM,
438 CodeGenFunction *CGF,
439 const VarDecl *var) {
440 // Return if this is a function parameter. We shouldn't try to
441 // rematerialize default arguments of function parameters.
442 if (isa<ParmVarDecl>(Val: var))
443 return nullptr;
444
445 QualType type = var->getType();
446
447 // We can only do this if the variable is const.
448 if (!type.isConstQualified()) return nullptr;
449
450 // Furthermore, in C++ we have to worry about mutable fields:
451 // C++ [dcl.type.cv]p4:
452 // Except that any class member declared mutable can be
453 // modified, any attempt to modify a const object during its
454 // lifetime results in undefined behavior.
455 if (CGM.getLangOpts().CPlusPlus && !isSafeForCXXConstantCapture(type))
456 return nullptr;
457
458 // If the variable doesn't have any initializer (shouldn't this be
459 // invalid?), it's not clear what we should do. Maybe capture as
460 // zero?
461 const Expr *init = var->getInit();
462 if (!init) return nullptr;
463
464 return ConstantEmitter(CGM, CGF).tryEmitAbstractForInitializer(D: *var);
465}
466
467/// Get the low bit of a nonzero character count. This is the
468/// alignment of the nth byte if the 0th byte is universally aligned.
469static CharUnits getLowBit(CharUnits v) {
470 return CharUnits::fromQuantity(Quantity: v.getQuantity() & (~v.getQuantity() + 1));
471}
472
473static void initializeForBlockHeader(CodeGenModule &CGM, CGBlockInfo &info,
474 SmallVectorImpl<llvm::Type*> &elementTypes) {
475
476 assert(elementTypes.empty());
477 if (CGM.getLangOpts().OpenCL) {
478 // The header is basically 'struct { int; int; generic void *;
479 // custom_fields; }'. Assert that struct is packed.
480 auto GenPtrAlign = CharUnits::fromQuantity(
481 Quantity: CGM.getTarget().getPointerAlign(AddrSpace: LangAS::opencl_generic) / 8);
482 auto GenPtrSize = CharUnits::fromQuantity(
483 Quantity: CGM.getTarget().getPointerWidth(AddrSpace: LangAS::opencl_generic) / 8);
484 assert(CGM.getIntSize() <= GenPtrSize);
485 assert(CGM.getIntAlign() <= GenPtrAlign);
486 assert((2 * CGM.getIntSize()).isMultipleOf(GenPtrAlign));
487 elementTypes.push_back(Elt: CGM.IntTy); /* total size */
488 elementTypes.push_back(Elt: CGM.IntTy); /* align */
489 elementTypes.push_back(
490 Elt: CGM.getOpenCLRuntime()
491 .getGenericVoidPointerType()); /* invoke function */
492 unsigned Offset =
493 2 * CGM.getIntSize().getQuantity() + GenPtrSize.getQuantity();
494 unsigned BlockAlign = GenPtrAlign.getQuantity();
495 if (auto *Helper =
496 CGM.getTargetCodeGenInfo().getTargetOpenCLBlockHelper()) {
497 for (auto *I : Helper->getCustomFieldTypes()) /* custom fields */ {
498 // TargetOpenCLBlockHelp needs to make sure the struct is packed.
499 // If necessary, add padding fields to the custom fields.
500 unsigned Align = CGM.getDataLayout().getABITypeAlign(Ty: I).value();
501 if (BlockAlign < Align)
502 BlockAlign = Align;
503 assert(Offset % Align == 0);
504 Offset += CGM.getDataLayout().getTypeAllocSize(Ty: I);
505 elementTypes.push_back(Elt: I);
506 }
507 }
508 info.BlockAlign = CharUnits::fromQuantity(Quantity: BlockAlign);
509 info.BlockSize = CharUnits::fromQuantity(Quantity: Offset);
510 } else {
511 // The header is basically 'struct { void *; int; int; void *; void *; }'.
512 // Assert that the struct is packed.
513 assert(CGM.getIntSize() <= CGM.getPointerSize());
514 assert(CGM.getIntAlign() <= CGM.getPointerAlign());
515 assert((2 * CGM.getIntSize()).isMultipleOf(CGM.getPointerAlign()));
516 info.BlockAlign = CGM.getPointerAlign();
517 info.BlockSize = 3 * CGM.getPointerSize() + 2 * CGM.getIntSize();
518 elementTypes.push_back(Elt: CGM.VoidPtrTy);
519 elementTypes.push_back(Elt: CGM.IntTy);
520 elementTypes.push_back(Elt: CGM.IntTy);
521 elementTypes.push_back(Elt: CGM.VoidPtrTy);
522 elementTypes.push_back(Elt: CGM.getBlockDescriptorType());
523 }
524}
525
526static QualType getCaptureFieldType(const CodeGenFunction &CGF,
527 const BlockDecl::Capture &CI) {
528 const VarDecl *VD = CI.getVariable();
529
530 // If the variable is captured by an enclosing block or lambda expression,
531 // use the type of the capture field.
532 if (CGF.BlockInfo && CI.isNested())
533 return CGF.BlockInfo->getCapture(var: VD).fieldType();
534 if (auto *FD = CGF.LambdaCaptureFields.lookup(VD))
535 return FD->getType();
536 // If the captured variable is a non-escaping __block variable, the field
537 // type is the reference type. If the variable is a __block variable that
538 // already has a reference type, the field type is the variable's type.
539 return VD->isNonEscapingByref() ?
540 CGF.getContext().getLValueReferenceType(T: VD->getType()) : VD->getType();
541}
542
543/// Compute the layout of the given block. Attempts to lay the block
544/// out with minimal space requirements.
545static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF,
546 CGBlockInfo &info) {
547 ASTContext &C = CGM.getContext();
548 const BlockDecl *block = info.getBlockDecl();
549
550 SmallVector<llvm::Type*, 8> elementTypes;
551 initializeForBlockHeader(CGM, info, elementTypes);
552 bool hasNonConstantCustomFields = false;
553 if (auto *OpenCLHelper =
554 CGM.getTargetCodeGenInfo().getTargetOpenCLBlockHelper())
555 hasNonConstantCustomFields =
556 !OpenCLHelper->areAllCustomFieldValuesConstant(Info: info);
557 if (!block->hasCaptures() && !hasNonConstantCustomFields) {
558 info.StructureType =
559 llvm::StructType::get(Context&: CGM.getLLVMContext(), Elements: elementTypes, isPacked: true);
560 info.CanBeGlobal = true;
561 return;
562 }
563 else if (C.getLangOpts().ObjC &&
564 CGM.getLangOpts().getGC() == LangOptions::NonGC)
565 info.HasCapturedVariableLayout = true;
566
567 if (block->doesNotEscape())
568 info.NoEscape = true;
569
570 // Collect the layout chunks.
571 SmallVector<BlockLayoutChunk, 16> layout;
572 layout.reserve(N: block->capturesCXXThis() +
573 (block->capture_end() - block->capture_begin()));
574
575 CharUnits maxFieldAlign;
576
577 // First, 'this'.
578 if (block->capturesCXXThis()) {
579 assert(CGF && CGF->CurFuncDecl && isa<CXXMethodDecl>(CGF->CurFuncDecl) &&
580 "Can't capture 'this' outside a method");
581 QualType thisType = cast<CXXMethodDecl>(Val: CGF->CurFuncDecl)->getThisType();
582
583 // Theoretically, this could be in a different address space, so
584 // don't assume standard pointer size/align.
585 llvm::Type *llvmType = CGM.getTypes().ConvertType(T: thisType);
586 auto TInfo = CGM.getContext().getTypeInfoInChars(T: thisType);
587 maxFieldAlign = std::max(a: maxFieldAlign, b: TInfo.Align);
588
589 addBlockLayout(align: TInfo.Align, size: TInfo.Width, capture: nullptr, type: llvmType, fieldType: thisType,
590 Layout&: layout, Info&: info, CGM);
591 }
592
593 // Next, all the block captures.
594 for (const auto &CI : block->captures()) {
595 const VarDecl *variable = CI.getVariable();
596
597 if (CI.isEscapingByref()) {
598 // Just use void* instead of a pointer to the byref type.
599 CharUnits align = CGM.getPointerAlign();
600 maxFieldAlign = std::max(a: maxFieldAlign, b: align);
601
602 // Since a __block variable cannot be captured by lambdas, its type and
603 // the capture field type should always match.
604 assert(CGF && getCaptureFieldType(*CGF, CI) == variable->getType() &&
605 "capture type differs from the variable type");
606 addBlockLayout(align, CGM.getPointerSize(), &CI, CGM.VoidPtrTy,
607 variable->getType(), layout, info, CGM);
608 continue;
609 }
610
611 // Otherwise, build a layout chunk with the size and alignment of
612 // the declaration.
613 if (llvm::Constant *constant = tryCaptureAsConstant(CGM, CGF, var: variable)) {
614 info.SortedCaptures.push_back(
615 Elt: CGBlockInfo::Capture::makeConstant(value: constant, Cap: &CI));
616 continue;
617 }
618
619 QualType VT = getCaptureFieldType(CGF: *CGF, CI);
620
621 if (CGM.getLangOpts().CPlusPlus)
622 if (const CXXRecordDecl *record = VT->getAsCXXRecordDecl())
623 if (CI.hasCopyExpr() || !record->hasTrivialDestructor()) {
624 info.HasCXXObject = true;
625 if (!record->isExternallyVisible())
626 info.CapturesNonExternalType = true;
627 }
628
629 CharUnits size = C.getTypeSizeInChars(T: VT);
630 CharUnits align = C.getDeclAlign(variable);
631
632 maxFieldAlign = std::max(a: maxFieldAlign, b: align);
633
634 llvm::Type *llvmType =
635 CGM.getTypes().ConvertTypeForMem(T: VT);
636
637 addBlockLayout(align, size, capture: &CI, type: llvmType, fieldType: VT, Layout&: layout, Info&: info, CGM);
638 }
639
640 // If that was everything, we're done here.
641 if (layout.empty()) {
642 info.StructureType =
643 llvm::StructType::get(Context&: CGM.getLLVMContext(), Elements: elementTypes, isPacked: true);
644 info.CanBeGlobal = true;
645 info.buildCaptureMap();
646 return;
647 }
648
649 // Sort the layout by alignment. We have to use a stable sort here
650 // to get reproducible results. There should probably be an
651 // llvm::array_pod_stable_sort.
652 llvm::stable_sort(Range&: layout);
653
654 // Needed for blocks layout info.
655 info.BlockHeaderForcedGapOffset = info.BlockSize;
656 info.BlockHeaderForcedGapSize = CharUnits::Zero();
657
658 CharUnits &blockSize = info.BlockSize;
659 info.BlockAlign = std::max(a: maxFieldAlign, b: info.BlockAlign);
660
661 // Assuming that the first byte in the header is maximally aligned,
662 // get the alignment of the first byte following the header.
663 CharUnits endAlign = getLowBit(v: blockSize);
664
665 // If the end of the header isn't satisfactorily aligned for the
666 // maximum thing, look for things that are okay with the header-end
667 // alignment, and keep appending them until we get something that's
668 // aligned right. This algorithm is only guaranteed optimal if
669 // that condition is satisfied at some point; otherwise we can get
670 // things like:
671 // header // next byte has alignment 4
672 // something_with_size_5; // next byte has alignment 1
673 // something_with_alignment_8;
674 // which has 7 bytes of padding, as opposed to the naive solution
675 // which might have less (?).
676 if (endAlign < maxFieldAlign) {
677 SmallVectorImpl<BlockLayoutChunk>::iterator
678 li = layout.begin() + 1, le = layout.end();
679
680 // Look for something that the header end is already
681 // satisfactorily aligned for.
682 for (; li != le && endAlign < li->Alignment; ++li)
683 ;
684
685 // If we found something that's naturally aligned for the end of
686 // the header, keep adding things...
687 if (li != le) {
688 SmallVectorImpl<BlockLayoutChunk>::iterator first = li;
689 for (; li != le; ++li) {
690 assert(endAlign >= li->Alignment);
691
692 li->setIndex(info, index: elementTypes.size(), offset: blockSize);
693 elementTypes.push_back(Elt: li->Type);
694 blockSize += li->Size;
695 endAlign = getLowBit(v: blockSize);
696
697 // ...until we get to the alignment of the maximum field.
698 if (endAlign >= maxFieldAlign) {
699 ++li;
700 break;
701 }
702 }
703 // Don't re-append everything we just appended.
704 layout.erase(CS: first, CE: li);
705 }
706 }
707
708 assert(endAlign == getLowBit(blockSize));
709
710 // At this point, we just have to add padding if the end align still
711 // isn't aligned right.
712 if (endAlign < maxFieldAlign) {
713 CharUnits newBlockSize = blockSize.alignTo(Align: maxFieldAlign);
714 CharUnits padding = newBlockSize - blockSize;
715
716 // If we haven't yet added any fields, remember that there was an
717 // initial gap; this need to go into the block layout bit map.
718 if (blockSize == info.BlockHeaderForcedGapOffset) {
719 info.BlockHeaderForcedGapSize = padding;
720 }
721
722 elementTypes.push_back(Elt: llvm::ArrayType::get(ElementType: CGM.Int8Ty,
723 NumElements: padding.getQuantity()));
724 blockSize = newBlockSize;
725 endAlign = getLowBit(v: blockSize); // might be > maxFieldAlign
726 }
727
728 assert(endAlign >= maxFieldAlign);
729 assert(endAlign == getLowBit(blockSize));
730 // Slam everything else on now. This works because they have
731 // strictly decreasing alignment and we expect that size is always a
732 // multiple of alignment.
733 for (SmallVectorImpl<BlockLayoutChunk>::iterator
734 li = layout.begin(), le = layout.end(); li != le; ++li) {
735 if (endAlign < li->Alignment) {
736 // size may not be multiple of alignment. This can only happen with
737 // an over-aligned variable. We will be adding a padding field to
738 // make the size be multiple of alignment.
739 CharUnits padding = li->Alignment - endAlign;
740 elementTypes.push_back(Elt: llvm::ArrayType::get(ElementType: CGM.Int8Ty,
741 NumElements: padding.getQuantity()));
742 blockSize += padding;
743 endAlign = getLowBit(v: blockSize);
744 }
745 assert(endAlign >= li->Alignment);
746 li->setIndex(info, index: elementTypes.size(), offset: blockSize);
747 elementTypes.push_back(Elt: li->Type);
748 blockSize += li->Size;
749 endAlign = getLowBit(v: blockSize);
750 }
751
752 info.buildCaptureMap();
753 info.StructureType =
754 llvm::StructType::get(Context&: CGM.getLLVMContext(), Elements: elementTypes, isPacked: true);
755}
756
757/// Emit a block literal expression in the current function.
758llvm::Value *CodeGenFunction::EmitBlockLiteral(const BlockExpr *blockExpr) {
759 // If the block has no captures, we won't have a pre-computed
760 // layout for it.
761 if (!blockExpr->getBlockDecl()->hasCaptures())
762 // The block literal is emitted as a global variable, and the block invoke
763 // function has to be extracted from its initializer.
764 if (llvm::Constant *Block = CGM.getAddrOfGlobalBlockIfEmitted(BE: blockExpr))
765 return Block;
766
767 CGBlockInfo blockInfo(blockExpr->getBlockDecl(), CurFn->getName());
768 computeBlockInfo(CGM, CGF: this, info&: blockInfo);
769 blockInfo.BlockExpression = blockExpr;
770 if (!blockInfo.CanBeGlobal)
771 blockInfo.LocalAddress = CreateTempAlloca(Ty: blockInfo.StructureType,
772 align: blockInfo.BlockAlign, Name: "block");
773 return EmitBlockLiteral(Info: blockInfo);
774}
775
776llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo) {
777 bool IsOpenCL = CGM.getContext().getLangOpts().OpenCL;
778 auto GenVoidPtrTy =
779 IsOpenCL ? CGM.getOpenCLRuntime().getGenericVoidPointerType() : VoidPtrTy;
780 LangAS GenVoidPtrAddr = IsOpenCL ? LangAS::opencl_generic : LangAS::Default;
781 auto GenVoidPtrSize = CharUnits::fromQuantity(
782 Quantity: CGM.getTarget().getPointerWidth(AddrSpace: GenVoidPtrAddr) / 8);
783 // Using the computed layout, generate the actual block function.
784 bool isLambdaConv = blockInfo.getBlockDecl()->isConversionFromLambda();
785 CodeGenFunction BlockCGF{CGM, true};
786 BlockCGF.SanOpts = SanOpts;
787 auto *InvokeFn = BlockCGF.GenerateBlockFunction(
788 GD: CurGD, Info: blockInfo, ldm: LocalDeclMap, IsLambdaConversionToBlock: isLambdaConv, BuildGlobalBlock: blockInfo.CanBeGlobal);
789 auto *blockFn = llvm::ConstantExpr::getPointerCast(C: InvokeFn, Ty: GenVoidPtrTy);
790
791 // If there is nothing to capture, we can emit this as a global block.
792 if (blockInfo.CanBeGlobal)
793 return CGM.getAddrOfGlobalBlockIfEmitted(BE: blockInfo.BlockExpression);
794
795 // Otherwise, we have to emit this as a local block.
796
797 Address blockAddr = blockInfo.LocalAddress;
798 assert(blockAddr.isValid() && "block has no address!");
799
800 llvm::Constant *isa;
801 llvm::Constant *descriptor;
802 BlockFlags flags;
803 if (!IsOpenCL) {
804 // If the block is non-escaping, set field 'isa 'to NSConcreteGlobalBlock
805 // and set the BLOCK_IS_GLOBAL bit of field 'flags'. Copying a non-escaping
806 // block just returns the original block and releasing it is a no-op.
807 llvm::Constant *blockISA = blockInfo.NoEscape
808 ? CGM.getNSConcreteGlobalBlock()
809 : CGM.getNSConcreteStackBlock();
810 isa = blockISA;
811
812 // Build the block descriptor.
813 descriptor = buildBlockDescriptor(CGM, blockInfo);
814
815 // Compute the initial on-stack block flags.
816 flags = BLOCK_HAS_SIGNATURE;
817 if (blockInfo.HasCapturedVariableLayout)
818 flags |= BLOCK_HAS_EXTENDED_LAYOUT;
819 if (blockInfo.NeedsCopyDispose)
820 flags |= BLOCK_HAS_COPY_DISPOSE;
821 if (blockInfo.HasCXXObject)
822 flags |= BLOCK_HAS_CXX_OBJ;
823 if (blockInfo.UsesStret)
824 flags |= BLOCK_USE_STRET;
825 if (blockInfo.NoEscape)
826 flags |= BLOCK_IS_NOESCAPE | BLOCK_IS_GLOBAL;
827 }
828
829 auto projectField = [&](unsigned index, const Twine &name) -> Address {
830 return Builder.CreateStructGEP(Addr: blockAddr, Index: index, Name: name);
831 };
832 auto storeField = [&](llvm::Value *value, unsigned index, const Twine &name) {
833 Builder.CreateStore(Val: value, Addr: projectField(index, name));
834 };
835
836 // Initialize the block header.
837 {
838 // We assume all the header fields are densely packed.
839 unsigned index = 0;
840 CharUnits offset;
841 auto addHeaderField = [&](llvm::Value *value, CharUnits size,
842 const Twine &name) {
843 storeField(value, index, name);
844 offset += size;
845 index++;
846 };
847
848 if (!IsOpenCL) {
849 addHeaderField(isa, getPointerSize(), "block.isa");
850 addHeaderField(llvm::ConstantInt::get(Ty: IntTy, V: flags.getBitMask()),
851 getIntSize(), "block.flags");
852 addHeaderField(llvm::ConstantInt::get(Ty: IntTy, V: 0), getIntSize(),
853 "block.reserved");
854 } else {
855 addHeaderField(
856 llvm::ConstantInt::get(Ty: IntTy, V: blockInfo.BlockSize.getQuantity()),
857 getIntSize(), "block.size");
858 addHeaderField(
859 llvm::ConstantInt::get(Ty: IntTy, V: blockInfo.BlockAlign.getQuantity()),
860 getIntSize(), "block.align");
861 }
862 addHeaderField(blockFn, GenVoidPtrSize, "block.invoke");
863 if (!IsOpenCL)
864 addHeaderField(descriptor, getPointerSize(), "block.descriptor");
865 else if (auto *Helper =
866 CGM.getTargetCodeGenInfo().getTargetOpenCLBlockHelper()) {
867 for (auto I : Helper->getCustomFieldValues(CGF&: *this, Info: blockInfo)) {
868 addHeaderField(
869 I.first,
870 CharUnits::fromQuantity(
871 Quantity: CGM.getDataLayout().getTypeAllocSize(Ty: I.first->getType())),
872 I.second);
873 }
874 }
875 }
876
877 // Finally, capture all the values into the block.
878 const BlockDecl *blockDecl = blockInfo.getBlockDecl();
879
880 // First, 'this'.
881 if (blockDecl->capturesCXXThis()) {
882 Address addr =
883 projectField(blockInfo.CXXThisIndex, "block.captured-this.addr");
884 Builder.CreateStore(Val: LoadCXXThis(), Addr: addr);
885 }
886
887 // Next, captured variables.
888 for (const auto &CI : blockDecl->captures()) {
889 const VarDecl *variable = CI.getVariable();
890 const CGBlockInfo::Capture &capture = blockInfo.getCapture(var: variable);
891
892 // Ignore constant captures.
893 if (capture.isConstant()) continue;
894
895 QualType type = capture.fieldType();
896
897 // This will be a [[type]]*, except that a byref entry will just be
898 // an i8**.
899 Address blockField = projectField(capture.getIndex(), "block.captured");
900
901 // Compute the address of the thing we're going to move into the
902 // block literal.
903 Address src = Address::invalid();
904
905 if (blockDecl->isConversionFromLambda()) {
906 // The lambda capture in a lambda's conversion-to-block-pointer is
907 // special; we'll simply emit it directly.
908 src = Address::invalid();
909 } else if (CI.isEscapingByref()) {
910 if (BlockInfo && CI.isNested()) {
911 // We need to use the capture from the enclosing block.
912 const CGBlockInfo::Capture &enclosingCapture =
913 BlockInfo->getCapture(var: variable);
914
915 // This is a [[type]]*, except that a byref entry will just be an i8**.
916 src = Builder.CreateStructGEP(Addr: LoadBlockStruct(),
917 Index: enclosingCapture.getIndex(),
918 Name: "block.capture.addr");
919 } else {
920 auto I = LocalDeclMap.find(variable);
921 assert(I != LocalDeclMap.end());
922 src = I->second;
923 }
924 } else {
925 DeclRefExpr declRef(getContext(), const_cast<VarDecl *>(variable),
926 /*RefersToEnclosingVariableOrCapture*/ CI.isNested(),
927 type.getNonReferenceType(), VK_LValue,
928 SourceLocation());
929 src = EmitDeclRefLValue(E: &declRef).getAddress(CGF&: *this);
930 };
931
932 // For byrefs, we just write the pointer to the byref struct into
933 // the block field. There's no need to chase the forwarding
934 // pointer at this point, since we're building something that will
935 // live a shorter life than the stack byref anyway.
936 if (CI.isEscapingByref()) {
937 // Get a void* that points to the byref struct.
938 llvm::Value *byrefPointer;
939 if (CI.isNested())
940 byrefPointer = Builder.CreateLoad(Addr: src, Name: "byref.capture");
941 else
942 byrefPointer = src.getPointer();
943
944 // Write that void* into the capture field.
945 Builder.CreateStore(Val: byrefPointer, Addr: blockField);
946
947 // If we have a copy constructor, evaluate that into the block field.
948 } else if (const Expr *copyExpr = CI.getCopyExpr()) {
949 if (blockDecl->isConversionFromLambda()) {
950 // If we have a lambda conversion, emit the expression
951 // directly into the block instead.
952 AggValueSlot Slot =
953 AggValueSlot::forAddr(addr: blockField, quals: Qualifiers(),
954 isDestructed: AggValueSlot::IsDestructed,
955 needsGC: AggValueSlot::DoesNotNeedGCBarriers,
956 isAliased: AggValueSlot::IsNotAliased,
957 mayOverlap: AggValueSlot::DoesNotOverlap);
958 EmitAggExpr(E: copyExpr, AS: Slot);
959 } else {
960 EmitSynthesizedCXXCopyCtor(Dest: blockField, Src: src, Exp: copyExpr);
961 }
962
963 // If it's a reference variable, copy the reference into the block field.
964 } else if (type->isReferenceType()) {
965 Builder.CreateStore(Val: src.getPointer(), Addr: blockField);
966
967 // If type is const-qualified, copy the value into the block field.
968 } else if (type.isConstQualified() &&
969 type.getObjCLifetime() == Qualifiers::OCL_Strong &&
970 CGM.getCodeGenOpts().OptimizationLevel != 0) {
971 llvm::Value *value = Builder.CreateLoad(Addr: src, Name: "captured");
972 Builder.CreateStore(Val: value, Addr: blockField);
973
974 // If this is an ARC __strong block-pointer variable, don't do a
975 // block copy.
976 //
977 // TODO: this can be generalized into the normal initialization logic:
978 // we should never need to do a block-copy when initializing a local
979 // variable, because the local variable's lifetime should be strictly
980 // contained within the stack block's.
981 } else if (type.getObjCLifetime() == Qualifiers::OCL_Strong &&
982 type->isBlockPointerType()) {
983 // Load the block and do a simple retain.
984 llvm::Value *value = Builder.CreateLoad(Addr: src, Name: "block.captured_block");
985 value = EmitARCRetainNonBlock(value);
986
987 // Do a primitive store to the block field.
988 Builder.CreateStore(Val: value, Addr: blockField);
989
990 // Otherwise, fake up a POD copy into the block field.
991 } else {
992 // Fake up a new variable so that EmitScalarInit doesn't think
993 // we're referring to the variable in its own initializer.
994 ImplicitParamDecl BlockFieldPseudoVar(getContext(), type,
995 ImplicitParamKind::Other);
996
997 // We use one of these or the other depending on whether the
998 // reference is nested.
999 DeclRefExpr declRef(getContext(), const_cast<VarDecl *>(variable),
1000 /*RefersToEnclosingVariableOrCapture*/ CI.isNested(),
1001 type, VK_LValue, SourceLocation());
1002
1003 ImplicitCastExpr l2r(ImplicitCastExpr::OnStack, type, CK_LValueToRValue,
1004 &declRef, VK_PRValue, FPOptionsOverride());
1005 // FIXME: Pass a specific location for the expr init so that the store is
1006 // attributed to a reasonable location - otherwise it may be attributed to
1007 // locations of subexpressions in the initialization.
1008 EmitExprAsInit(&l2r, &BlockFieldPseudoVar,
1009 MakeAddrLValue(Addr: blockField, T: type, Source: AlignmentSource::Decl),
1010 /*captured by init*/ false);
1011 }
1012
1013 // Push a cleanup for the capture if necessary.
1014 if (!blockInfo.NoEscape && !blockInfo.NeedsCopyDispose)
1015 continue;
1016
1017 // Ignore __block captures; there's nothing special in the on-stack block
1018 // that we need to do for them.
1019 if (CI.isByRef())
1020 continue;
1021
1022 // Ignore objects that aren't destructed.
1023 QualType::DestructionKind dtorKind = type.isDestructedType();
1024 if (dtorKind == QualType::DK_none)
1025 continue;
1026
1027 CodeGenFunction::Destroyer *destroyer;
1028
1029 // Block captures count as local values and have imprecise semantics.
1030 // They also can't be arrays, so need to worry about that.
1031 //
1032 // For const-qualified captures, emit clang.arc.use to ensure the captured
1033 // object doesn't get released while we are still depending on its validity
1034 // within the block.
1035 if (type.isConstQualified() &&
1036 type.getObjCLifetime() == Qualifiers::OCL_Strong &&
1037 CGM.getCodeGenOpts().OptimizationLevel != 0) {
1038 assert(CGM.getLangOpts().ObjCAutoRefCount &&
1039 "expected ObjC ARC to be enabled");
1040 destroyer = emitARCIntrinsicUse;
1041 } else if (dtorKind == QualType::DK_objc_strong_lifetime) {
1042 destroyer = destroyARCStrongImprecise;
1043 } else {
1044 destroyer = getDestroyer(destructionKind: dtorKind);
1045 }
1046
1047 CleanupKind cleanupKind = NormalCleanup;
1048 bool useArrayEHCleanup = needsEHCleanup(kind: dtorKind);
1049 if (useArrayEHCleanup)
1050 cleanupKind = NormalAndEHCleanup;
1051
1052 // Extend the lifetime of the capture to the end of the scope enclosing the
1053 // block expression except when the block decl is in the list of RetExpr's
1054 // cleanup objects, in which case its lifetime ends after the full
1055 // expression.
1056 auto IsBlockDeclInRetExpr = [&]() {
1057 auto *EWC = llvm::dyn_cast_or_null<ExprWithCleanups>(Val: RetExpr);
1058 if (EWC)
1059 for (auto &C : EWC->getObjects())
1060 if (auto *BD = C.dyn_cast<BlockDecl *>())
1061 if (BD == blockDecl)
1062 return true;
1063 return false;
1064 };
1065
1066 if (IsBlockDeclInRetExpr())
1067 pushDestroy(kind: cleanupKind, addr: blockField, type, destroyer, useEHCleanupForArray: useArrayEHCleanup);
1068 else
1069 pushLifetimeExtendedDestroy(kind: cleanupKind, addr: blockField, type, destroyer,
1070 useEHCleanupForArray: useArrayEHCleanup);
1071 }
1072
1073 // Cast to the converted block-pointer type, which happens (somewhat
1074 // unfortunately) to be a pointer to function type.
1075 llvm::Value *result = Builder.CreatePointerCast(
1076 V: blockAddr.getPointer(), DestTy: ConvertType(blockInfo.getBlockExpr()->getType()));
1077
1078 if (IsOpenCL) {
1079 CGM.getOpenCLRuntime().recordBlockInfo(E: blockInfo.BlockExpression, InvokeF: InvokeFn,
1080 Block: result, BlockTy: blockInfo.StructureType);
1081 }
1082
1083 return result;
1084}
1085
1086
1087llvm::Type *CodeGenModule::getBlockDescriptorType() {
1088 if (BlockDescriptorType)
1089 return BlockDescriptorType;
1090
1091 llvm::Type *UnsignedLongTy =
1092 getTypes().ConvertType(T: getContext().UnsignedLongTy);
1093
1094 // struct __block_descriptor {
1095 // unsigned long reserved;
1096 // unsigned long block_size;
1097 //
1098 // // later, the following will be added
1099 //
1100 // struct {
1101 // void (*copyHelper)();
1102 // void (*copyHelper)();
1103 // } helpers; // !!! optional
1104 //
1105 // const char *signature; // the block signature
1106 // const char *layout; // reserved
1107 // };
1108 BlockDescriptorType = llvm::StructType::create(
1109 Name: "struct.__block_descriptor", elt1: UnsignedLongTy, elts: UnsignedLongTy);
1110
1111 // Now form a pointer to that.
1112 unsigned AddrSpace = 0;
1113 if (getLangOpts().OpenCL)
1114 AddrSpace = getContext().getTargetAddressSpace(AS: LangAS::opencl_constant);
1115 BlockDescriptorType = llvm::PointerType::get(ElementType: BlockDescriptorType, AddressSpace: AddrSpace);
1116 return BlockDescriptorType;
1117}
1118
1119llvm::Type *CodeGenModule::getGenericBlockLiteralType() {
1120 if (GenericBlockLiteralType)
1121 return GenericBlockLiteralType;
1122
1123 llvm::Type *BlockDescPtrTy = getBlockDescriptorType();
1124
1125 if (getLangOpts().OpenCL) {
1126 // struct __opencl_block_literal_generic {
1127 // int __size;
1128 // int __align;
1129 // __generic void *__invoke;
1130 // /* custom fields */
1131 // };
1132 SmallVector<llvm::Type *, 8> StructFields(
1133 {IntTy, IntTy, getOpenCLRuntime().getGenericVoidPointerType()});
1134 if (auto *Helper = getTargetCodeGenInfo().getTargetOpenCLBlockHelper()) {
1135 llvm::append_range(C&: StructFields, R: Helper->getCustomFieldTypes());
1136 }
1137 GenericBlockLiteralType = llvm::StructType::create(
1138 Elements: StructFields, Name: "struct.__opencl_block_literal_generic");
1139 } else {
1140 // struct __block_literal_generic {
1141 // void *__isa;
1142 // int __flags;
1143 // int __reserved;
1144 // void (*__invoke)(void *);
1145 // struct __block_descriptor *__descriptor;
1146 // };
1147 GenericBlockLiteralType =
1148 llvm::StructType::create(Name: "struct.__block_literal_generic", elt1: VoidPtrTy,
1149 elts: IntTy, elts: IntTy, elts: VoidPtrTy, elts: BlockDescPtrTy);
1150 }
1151
1152 return GenericBlockLiteralType;
1153}
1154
1155RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr *E,
1156 ReturnValueSlot ReturnValue) {
1157 const auto *BPT = E->getCallee()->getType()->castAs<BlockPointerType>();
1158 llvm::Value *BlockPtr = EmitScalarExpr(E: E->getCallee());
1159 llvm::Type *GenBlockTy = CGM.getGenericBlockLiteralType();
1160 llvm::Value *Func = nullptr;
1161 QualType FnType = BPT->getPointeeType();
1162 ASTContext &Ctx = getContext();
1163 CallArgList Args;
1164
1165 if (getLangOpts().OpenCL) {
1166 // For OpenCL, BlockPtr is already casted to generic block literal.
1167
1168 // First argument of a block call is a generic block literal casted to
1169 // generic void pointer, i.e. i8 addrspace(4)*
1170 llvm::Type *GenericVoidPtrTy =
1171 CGM.getOpenCLRuntime().getGenericVoidPointerType();
1172 llvm::Value *BlockDescriptor = Builder.CreatePointerCast(
1173 V: BlockPtr, DestTy: GenericVoidPtrTy);
1174 QualType VoidPtrQualTy = Ctx.getPointerType(
1175 Ctx.getAddrSpaceQualType(T: Ctx.VoidTy, AddressSpace: LangAS::opencl_generic));
1176 Args.add(rvalue: RValue::get(V: BlockDescriptor), type: VoidPtrQualTy);
1177 // And the rest of the arguments.
1178 EmitCallArgs(Args, Prototype: FnType->getAs<FunctionProtoType>(), ArgRange: E->arguments());
1179
1180 // We *can* call the block directly unless it is a function argument.
1181 if (!isa<ParmVarDecl>(Val: E->getCalleeDecl()))
1182 Func = CGM.getOpenCLRuntime().getInvokeFunction(E: E->getCallee());
1183 else {
1184 llvm::Value *FuncPtr = Builder.CreateStructGEP(Ty: GenBlockTy, Ptr: BlockPtr, Idx: 2);
1185 Func = Builder.CreateAlignedLoad(GenericVoidPtrTy, FuncPtr,
1186 getPointerAlign());
1187 }
1188 } else {
1189 // Bitcast the block literal to a generic block literal.
1190 BlockPtr =
1191 Builder.CreatePointerCast(V: BlockPtr, DestTy: UnqualPtrTy, Name: "block.literal");
1192 // Get pointer to the block invoke function
1193 llvm::Value *FuncPtr = Builder.CreateStructGEP(Ty: GenBlockTy, Ptr: BlockPtr, Idx: 3);
1194
1195 // First argument is a block literal casted to a void pointer
1196 BlockPtr = Builder.CreatePointerCast(V: BlockPtr, DestTy: VoidPtrTy);
1197 Args.add(rvalue: RValue::get(V: BlockPtr), type: Ctx.VoidPtrTy);
1198 // And the rest of the arguments.
1199 EmitCallArgs(Args, Prototype: FnType->getAs<FunctionProtoType>(), ArgRange: E->arguments());
1200
1201 // Load the function.
1202 Func = Builder.CreateAlignedLoad(VoidPtrTy, FuncPtr, getPointerAlign());
1203 }
1204
1205 const FunctionType *FuncTy = FnType->castAs<FunctionType>();
1206 const CGFunctionInfo &FnInfo =
1207 CGM.getTypes().arrangeBlockFunctionCall(args: Args, type: FuncTy);
1208
1209 // Prepare the callee.
1210 CGCallee Callee(CGCalleeInfo(), Func);
1211
1212 // And call the block.
1213 return EmitCall(CallInfo: FnInfo, Callee, ReturnValue, Args);
1214}
1215
1216Address CodeGenFunction::GetAddrOfBlockDecl(const VarDecl *variable) {
1217 assert(BlockInfo && "evaluating block ref without block information?");
1218 const CGBlockInfo::Capture &capture = BlockInfo->getCapture(var: variable);
1219
1220 // Handle constant captures.
1221 if (capture.isConstant()) return LocalDeclMap.find(variable)->second;
1222
1223 Address addr = Builder.CreateStructGEP(Addr: LoadBlockStruct(), Index: capture.getIndex(),
1224 Name: "block.capture.addr");
1225
1226 if (variable->isEscapingByref()) {
1227 // addr should be a void** right now. Load, then cast the result
1228 // to byref*.
1229
1230 auto &byrefInfo = getBlockByrefInfo(var: variable);
1231 addr = Address(Builder.CreateLoad(Addr: addr), byrefInfo.Type,
1232 byrefInfo.ByrefAlignment);
1233
1234 addr = emitBlockByrefAddress(addr, byrefInfo, /*follow*/ true,
1235 variable->getName());
1236 }
1237
1238 assert((!variable->isNonEscapingByref() ||
1239 capture.fieldType()->isReferenceType()) &&
1240 "the capture field of a non-escaping variable should have a "
1241 "reference type");
1242 if (capture.fieldType()->isReferenceType())
1243 addr = EmitLoadOfReference(RefLVal: MakeAddrLValue(Addr: addr, T: capture.fieldType()));
1244
1245 return addr;
1246}
1247
1248void CodeGenModule::setAddrOfGlobalBlock(const BlockExpr *BE,
1249 llvm::Constant *Addr) {
1250 bool Ok = EmittedGlobalBlocks.insert(KV: std::make_pair(x&: BE, y&: Addr)).second;
1251 (void)Ok;
1252 assert(Ok && "Trying to replace an already-existing global block!");
1253}
1254
1255llvm::Constant *
1256CodeGenModule::GetAddrOfGlobalBlock(const BlockExpr *BE,
1257 StringRef Name) {
1258 if (llvm::Constant *Block = getAddrOfGlobalBlockIfEmitted(BE))
1259 return Block;
1260
1261 CGBlockInfo blockInfo(BE->getBlockDecl(), Name);
1262 blockInfo.BlockExpression = BE;
1263
1264 // Compute information about the layout, etc., of this block.
1265 computeBlockInfo(CGM&: *this, CGF: nullptr, info&: blockInfo);
1266
1267 // Using that metadata, generate the actual block function.
1268 {
1269 CodeGenFunction::DeclMapTy LocalDeclMap;
1270 CodeGenFunction(*this).GenerateBlockFunction(
1271 GD: GlobalDecl(), Info: blockInfo, ldm: LocalDeclMap,
1272 /*IsLambdaConversionToBlock*/ false, /*BuildGlobalBlock*/ true);
1273 }
1274
1275 return getAddrOfGlobalBlockIfEmitted(BE);
1276}
1277
1278static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
1279 const CGBlockInfo &blockInfo,
1280 llvm::Constant *blockFn) {
1281 assert(blockInfo.CanBeGlobal);
1282 // Callers should detect this case on their own: calling this function
1283 // generally requires computing layout information, which is a waste of time
1284 // if we've already emitted this block.
1285 assert(!CGM.getAddrOfGlobalBlockIfEmitted(blockInfo.BlockExpression) &&
1286 "Refusing to re-emit a global block.");
1287
1288 // Generate the constants for the block literal initializer.
1289 ConstantInitBuilder builder(CGM);
1290 auto fields = builder.beginStruct();
1291
1292 bool IsOpenCL = CGM.getLangOpts().OpenCL;
1293 bool IsWindows = CGM.getTarget().getTriple().isOSWindows();
1294 if (!IsOpenCL) {
1295 // isa
1296 if (IsWindows)
1297 fields.addNullPointer(ptrTy: CGM.Int8PtrPtrTy);
1298 else
1299 fields.add(value: CGM.getNSConcreteGlobalBlock());
1300
1301 // __flags
1302 BlockFlags flags = BLOCK_IS_GLOBAL | BLOCK_HAS_SIGNATURE;
1303 if (blockInfo.UsesStret)
1304 flags |= BLOCK_USE_STRET;
1305
1306 fields.addInt(intTy: CGM.IntTy, value: flags.getBitMask());
1307
1308 // Reserved
1309 fields.addInt(intTy: CGM.IntTy, value: 0);
1310 } else {
1311 fields.addInt(intTy: CGM.IntTy, value: blockInfo.BlockSize.getQuantity());
1312 fields.addInt(intTy: CGM.IntTy, value: blockInfo.BlockAlign.getQuantity());
1313 }
1314
1315 // Function
1316 fields.add(value: blockFn);
1317
1318 if (!IsOpenCL) {
1319 // Descriptor
1320 fields.add(value: buildBlockDescriptor(CGM, blockInfo));
1321 } else if (auto *Helper =
1322 CGM.getTargetCodeGenInfo().getTargetOpenCLBlockHelper()) {
1323 for (auto *I : Helper->getCustomFieldValues(CGM, Info: blockInfo)) {
1324 fields.add(value: I);
1325 }
1326 }
1327
1328 unsigned AddrSpace = 0;
1329 if (CGM.getContext().getLangOpts().OpenCL)
1330 AddrSpace = CGM.getContext().getTargetAddressSpace(AS: LangAS::opencl_global);
1331
1332 llvm::GlobalVariable *literal = fields.finishAndCreateGlobal(
1333 args: "__block_literal_global", args: blockInfo.BlockAlign,
1334 /*constant*/ args: !IsWindows, args: llvm::GlobalVariable::InternalLinkage, args&: AddrSpace);
1335
1336 literal->addAttribute(Kind: "objc_arc_inert");
1337
1338 // Windows does not allow globals to be initialised to point to globals in
1339 // different DLLs. Any such variables must run code to initialise them.
1340 if (IsWindows) {
1341 auto *Init = llvm::Function::Create(Ty: llvm::FunctionType::get(Result: CGM.VoidTy,
1342 isVarArg: {}), Linkage: llvm::GlobalValue::InternalLinkage, N: ".block_isa_init",
1343 M: &CGM.getModule());
1344 llvm::IRBuilder<> b(llvm::BasicBlock::Create(Context&: CGM.getLLVMContext(), Name: "entry",
1345 Parent: Init));
1346 b.CreateAlignedStore(Val: CGM.getNSConcreteGlobalBlock(),
1347 Ptr: b.CreateStructGEP(Ty: literal->getValueType(), Ptr: literal, Idx: 0),
1348 Align: CGM.getPointerAlign().getAsAlign());
1349 b.CreateRetVoid();
1350 // We can't use the normal LLVM global initialisation array, because we
1351 // need to specify that this runs early in library initialisation.
1352 auto *InitVar = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
1353 /*isConstant*/true, llvm::GlobalValue::InternalLinkage,
1354 Init, ".block_isa_init_ptr");
1355 InitVar->setSection(".CRT$XCLa");
1356 CGM.addUsedGlobal(GV: InitVar);
1357 }
1358
1359 // Return a constant of the appropriately-casted type.
1360 llvm::Type *RequiredType =
1361 CGM.getTypes().ConvertType(T: blockInfo.getBlockExpr()->getType());
1362 llvm::Constant *Result =
1363 llvm::ConstantExpr::getPointerCast(C: literal, Ty: RequiredType);
1364 CGM.setAddrOfGlobalBlock(BE: blockInfo.BlockExpression, Addr: Result);
1365 if (CGM.getContext().getLangOpts().OpenCL)
1366 CGM.getOpenCLRuntime().recordBlockInfo(
1367 E: blockInfo.BlockExpression,
1368 InvokeF: cast<llvm::Function>(Val: blockFn->stripPointerCasts()), Block: Result,
1369 BlockTy: literal->getValueType());
1370 return Result;
1371}
1372
1373void CodeGenFunction::setBlockContextParameter(const ImplicitParamDecl *D,
1374 unsigned argNum,
1375 llvm::Value *arg) {
1376 assert(BlockInfo && "not emitting prologue of block invocation function?!");
1377
1378 // Allocate a stack slot like for any local variable to guarantee optimal
1379 // debug info at -O0. The mem2reg pass will eliminate it when optimizing.
1380 Address alloc = CreateMemTemp(D->getType(), D->getName() + ".addr");
1381 Builder.CreateStore(Val: arg, Addr: alloc);
1382 if (CGDebugInfo *DI = getDebugInfo()) {
1383 if (CGM.getCodeGenOpts().hasReducedDebugInfo()) {
1384 DI->setLocation(D->getLocation());
1385 DI->EmitDeclareOfBlockLiteralArgVariable(
1386 block: *BlockInfo, Name: D->getName(), ArgNo: argNum,
1387 LocalAddr: cast<llvm::AllocaInst>(Val: alloc.getPointer()), Builder);
1388 }
1389 }
1390
1391 SourceLocation StartLoc = BlockInfo->getBlockExpr()->getBody()->getBeginLoc();
1392 ApplyDebugLocation Scope(*this, StartLoc);
1393
1394 // Instead of messing around with LocalDeclMap, just set the value
1395 // directly as BlockPointer.
1396 BlockPointer = Builder.CreatePointerCast(
1397 V: arg,
1398 DestTy: llvm::PointerType::get(
1399 C&: getLLVMContext(),
1400 AddressSpace: getContext().getLangOpts().OpenCL
1401 ? getContext().getTargetAddressSpace(AS: LangAS::opencl_generic)
1402 : 0),
1403 Name: "block");
1404}
1405
1406Address CodeGenFunction::LoadBlockStruct() {
1407 assert(BlockInfo && "not in a block invocation function!");
1408 assert(BlockPointer && "no block pointer set!");
1409 return Address(BlockPointer, BlockInfo->StructureType, BlockInfo->BlockAlign);
1410}
1411
1412llvm::Function *CodeGenFunction::GenerateBlockFunction(
1413 GlobalDecl GD, const CGBlockInfo &blockInfo, const DeclMapTy &ldm,
1414 bool IsLambdaConversionToBlock, bool BuildGlobalBlock) {
1415 const BlockDecl *blockDecl = blockInfo.getBlockDecl();
1416
1417 CurGD = GD;
1418
1419 CurEHLocation = blockInfo.getBlockExpr()->getEndLoc();
1420
1421 BlockInfo = &blockInfo;
1422
1423 // Arrange for local static and local extern declarations to appear
1424 // to be local to this function as well, in case they're directly
1425 // referenced in a block.
1426 for (DeclMapTy::const_iterator i = ldm.begin(), e = ldm.end(); i != e; ++i) {
1427 const auto *var = dyn_cast<VarDecl>(Val: i->first);
1428 if (var && !var->hasLocalStorage())
1429 setAddrOfLocalVar(VD: var, Addr: i->second);
1430 }
1431
1432 // Begin building the function declaration.
1433
1434 // Build the argument list.
1435 FunctionArgList args;
1436
1437 // The first argument is the block pointer. Just take it as a void*
1438 // and cast it later.
1439 QualType selfTy = getContext().VoidPtrTy;
1440
1441 // For OpenCL passed block pointer can be private AS local variable or
1442 // global AS program scope variable (for the case with and without captures).
1443 // Generic AS is used therefore to be able to accommodate both private and
1444 // generic AS in one implementation.
1445 if (getLangOpts().OpenCL)
1446 selfTy = getContext().getPointerType(getContext().getAddrSpaceQualType(
1447 T: getContext().VoidTy, AddressSpace: LangAS::opencl_generic));
1448
1449 IdentifierInfo *II = &CGM.getContext().Idents.get(Name: ".block_descriptor");
1450
1451 ImplicitParamDecl SelfDecl(getContext(), const_cast<BlockDecl *>(blockDecl),
1452 SourceLocation(), II, selfTy,
1453 ImplicitParamKind::ObjCSelf);
1454 args.push_back(&SelfDecl);
1455
1456 // Now add the rest of the parameters.
1457 args.append(in_start: blockDecl->param_begin(), in_end: blockDecl->param_end());
1458
1459 // Create the function declaration.
1460 const FunctionProtoType *fnType = blockInfo.getBlockExpr()->getFunctionType();
1461 const CGFunctionInfo &fnInfo =
1462 CGM.getTypes().arrangeBlockFunctionDeclaration(type: fnType, args);
1463 if (CGM.ReturnSlotInterferesWithArgs(FI: fnInfo))
1464 blockInfo.UsesStret = true;
1465
1466 llvm::FunctionType *fnLLVMType = CGM.getTypes().GetFunctionType(Info: fnInfo);
1467
1468 StringRef name = CGM.getBlockMangledName(GD, BD: blockDecl);
1469 llvm::Function *fn = llvm::Function::Create(
1470 Ty: fnLLVMType, Linkage: llvm::GlobalValue::InternalLinkage, N: name, M: &CGM.getModule());
1471 CGM.SetInternalFunctionAttributes(GD: blockDecl, F: fn, FI: fnInfo);
1472
1473 if (BuildGlobalBlock) {
1474 auto GenVoidPtrTy = getContext().getLangOpts().OpenCL
1475 ? CGM.getOpenCLRuntime().getGenericVoidPointerType()
1476 : VoidPtrTy;
1477 buildGlobalBlock(CGM, blockInfo,
1478 blockFn: llvm::ConstantExpr::getPointerCast(C: fn, Ty: GenVoidPtrTy));
1479 }
1480
1481 // Begin generating the function.
1482 StartFunction(GD: blockDecl, RetTy: fnType->getReturnType(), Fn: fn, FnInfo: fnInfo, Args: args,
1483 Loc: blockDecl->getLocation(),
1484 StartLoc: blockInfo.getBlockExpr()->getBody()->getBeginLoc());
1485
1486 // Okay. Undo some of what StartFunction did.
1487
1488 // At -O0 we generate an explicit alloca for the BlockPointer, so the RA
1489 // won't delete the dbg.declare intrinsics for captured variables.
1490 llvm::Value *BlockPointerDbgLoc = BlockPointer;
1491 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1492 // Allocate a stack slot for it, so we can point the debugger to it
1493 Address Alloca = CreateTempAlloca(BlockPointer->getType(),
1494 getPointerAlign(),
1495 "block.addr");
1496 // Set the DebugLocation to empty, so the store is recognized as a
1497 // frame setup instruction by llvm::DwarfDebug::beginFunction().
1498 auto NL = ApplyDebugLocation::CreateEmpty(CGF&: *this);
1499 Builder.CreateStore(Val: BlockPointer, Addr: Alloca);
1500 BlockPointerDbgLoc = Alloca.getPointer();
1501 }
1502
1503 // If we have a C++ 'this' reference, go ahead and force it into
1504 // existence now.
1505 if (blockDecl->capturesCXXThis()) {
1506 Address addr = Builder.CreateStructGEP(
1507 Addr: LoadBlockStruct(), Index: blockInfo.CXXThisIndex, Name: "block.captured-this");
1508 CXXThisValue = Builder.CreateLoad(Addr: addr, Name: "this");
1509 }
1510
1511 // Also force all the constant captures.
1512 for (const auto &CI : blockDecl->captures()) {
1513 const VarDecl *variable = CI.getVariable();
1514 const CGBlockInfo::Capture &capture = blockInfo.getCapture(var: variable);
1515 if (!capture.isConstant()) continue;
1516
1517 CharUnits align = getContext().getDeclAlign(variable);
1518 Address alloca =
1519 CreateMemTemp(variable->getType(), align, "block.captured-const");
1520
1521 Builder.CreateStore(Val: capture.getConstant(), Addr: alloca);
1522
1523 setAddrOfLocalVar(VD: variable, Addr: alloca);
1524 }
1525
1526 // Save a spot to insert the debug information for all the DeclRefExprs.
1527 llvm::BasicBlock *entry = Builder.GetInsertBlock();
1528 llvm::BasicBlock::iterator entry_ptr = Builder.GetInsertPoint();
1529 --entry_ptr;
1530
1531 if (IsLambdaConversionToBlock)
1532 EmitLambdaBlockInvokeBody();
1533 else {
1534 PGO.assignRegionCounters(GD: GlobalDecl(blockDecl), Fn: fn);
1535 incrementProfileCounter(S: blockDecl->getBody());
1536 EmitStmt(S: blockDecl->getBody());
1537 }
1538
1539 // Remember where we were...
1540 llvm::BasicBlock *resume = Builder.GetInsertBlock();
1541
1542 // Go back to the entry.
1543 ++entry_ptr;
1544 Builder.SetInsertPoint(TheBB: entry, IP: entry_ptr);
1545
1546 // Emit debug information for all the DeclRefExprs.
1547 // FIXME: also for 'this'
1548 if (CGDebugInfo *DI = getDebugInfo()) {
1549 for (const auto &CI : blockDecl->captures()) {
1550 const VarDecl *variable = CI.getVariable();
1551 DI->EmitLocation(Builder, Loc: variable->getLocation());
1552
1553 if (CGM.getCodeGenOpts().hasReducedDebugInfo()) {
1554 const CGBlockInfo::Capture &capture = blockInfo.getCapture(var: variable);
1555 if (capture.isConstant()) {
1556 auto addr = LocalDeclMap.find(variable)->second;
1557 (void)DI->EmitDeclareOfAutoVariable(Decl: variable, AI: addr.getPointer(),
1558 Builder);
1559 continue;
1560 }
1561
1562 DI->EmitDeclareOfBlockDeclRefVariable(
1563 variable, storage: BlockPointerDbgLoc, Builder, blockInfo,
1564 InsertPoint: entry_ptr == entry->end() ? nullptr : &*entry_ptr);
1565 }
1566 }
1567 // Recover location if it was changed in the above loop.
1568 DI->EmitLocation(Builder,
1569 Loc: cast<CompoundStmt>(Val: blockDecl->getBody())->getRBracLoc());
1570 }
1571
1572 // And resume where we left off.
1573 if (resume == nullptr)
1574 Builder.ClearInsertionPoint();
1575 else
1576 Builder.SetInsertPoint(resume);
1577
1578 FinishFunction(EndLoc: cast<CompoundStmt>(Val: blockDecl->getBody())->getRBracLoc());
1579
1580 return fn;
1581}
1582
1583static std::pair<BlockCaptureEntityKind, BlockFieldFlags>
1584computeCopyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T,
1585 const LangOptions &LangOpts) {
1586 if (CI.getCopyExpr()) {
1587 assert(!CI.isByRef());
1588 // don't bother computing flags
1589 return std::make_pair(x: BlockCaptureEntityKind::CXXRecord, y: BlockFieldFlags());
1590 }
1591 BlockFieldFlags Flags;
1592 if (CI.isEscapingByref()) {
1593 Flags = BLOCK_FIELD_IS_BYREF;
1594 if (T.isObjCGCWeak())
1595 Flags |= BLOCK_FIELD_IS_WEAK;
1596 return std::make_pair(x: BlockCaptureEntityKind::BlockObject, y&: Flags);
1597 }
1598
1599 Flags = BLOCK_FIELD_IS_OBJECT;
1600 bool isBlockPointer = T->isBlockPointerType();
1601 if (isBlockPointer)
1602 Flags = BLOCK_FIELD_IS_BLOCK;
1603
1604 switch (T.isNonTrivialToPrimitiveCopy()) {
1605 case QualType::PCK_Struct:
1606 return std::make_pair(x: BlockCaptureEntityKind::NonTrivialCStruct,
1607 y: BlockFieldFlags());
1608 case QualType::PCK_ARCWeak:
1609 // We need to register __weak direct captures with the runtime.
1610 return std::make_pair(x: BlockCaptureEntityKind::ARCWeak, y&: Flags);
1611 case QualType::PCK_ARCStrong:
1612 // We need to retain the copied value for __strong direct captures.
1613 // If it's a block pointer, we have to copy the block and assign that to
1614 // the destination pointer, so we might as well use _Block_object_assign.
1615 // Otherwise we can avoid that.
1616 return std::make_pair(x: !isBlockPointer ? BlockCaptureEntityKind::ARCStrong
1617 : BlockCaptureEntityKind::BlockObject,
1618 y&: Flags);
1619 case QualType::PCK_Trivial:
1620 case QualType::PCK_VolatileTrivial: {
1621 if (!T->isObjCRetainableType())
1622 // For all other types, the memcpy is fine.
1623 return std::make_pair(x: BlockCaptureEntityKind::None, y: BlockFieldFlags());
1624
1625 // Honor the inert __unsafe_unretained qualifier, which doesn't actually
1626 // make it into the type system.
1627 if (T->isObjCInertUnsafeUnretainedType())
1628 return std::make_pair(x: BlockCaptureEntityKind::None, y: BlockFieldFlags());
1629
1630 // Special rules for ARC captures:
1631 Qualifiers QS = T.getQualifiers();
1632
1633 // Non-ARC captures of retainable pointers are strong and
1634 // therefore require a call to _Block_object_assign.
1635 if (!QS.getObjCLifetime() && !LangOpts.ObjCAutoRefCount)
1636 return std::make_pair(x: BlockCaptureEntityKind::BlockObject, y&: Flags);
1637
1638 // Otherwise the memcpy is fine.
1639 return std::make_pair(x: BlockCaptureEntityKind::None, y: BlockFieldFlags());
1640 }
1641 }
1642 llvm_unreachable("after exhaustive PrimitiveCopyKind switch");
1643}
1644
1645namespace {
1646/// Release a __block variable.
1647struct CallBlockRelease final : EHScopeStack::Cleanup {
1648 Address Addr;
1649 BlockFieldFlags FieldFlags;
1650 bool LoadBlockVarAddr, CanThrow;
1651
1652 CallBlockRelease(Address Addr, BlockFieldFlags Flags, bool LoadValue,
1653 bool CT)
1654 : Addr(Addr), FieldFlags(Flags), LoadBlockVarAddr(LoadValue),
1655 CanThrow(CT) {}
1656
1657 void Emit(CodeGenFunction &CGF, Flags flags) override {
1658 llvm::Value *BlockVarAddr;
1659 if (LoadBlockVarAddr) {
1660 BlockVarAddr = CGF.Builder.CreateLoad(Addr);
1661 } else {
1662 BlockVarAddr = Addr.getPointer();
1663 }
1664
1665 CGF.BuildBlockRelease(DeclPtr: BlockVarAddr, flags: FieldFlags, CanThrow);
1666 }
1667};
1668} // end anonymous namespace
1669
1670/// Check if \p T is a C++ class that has a destructor that can throw.
1671bool CodeGenFunction::cxxDestructorCanThrow(QualType T) {
1672 if (const auto *RD = T->getAsCXXRecordDecl())
1673 if (const CXXDestructorDecl *DD = RD->getDestructor())
1674 return DD->getType()->castAs<FunctionProtoType>()->canThrow();
1675 return false;
1676}
1677
1678// Return a string that has the information about a capture.
1679static std::string getBlockCaptureStr(const CGBlockInfo::Capture &Cap,
1680 CaptureStrKind StrKind,
1681 CharUnits BlockAlignment,
1682 CodeGenModule &CGM) {
1683 std::string Str;
1684 ASTContext &Ctx = CGM.getContext();
1685 const BlockDecl::Capture &CI = *Cap.Cap;
1686 QualType CaptureTy = CI.getVariable()->getType();
1687
1688 BlockCaptureEntityKind Kind;
1689 BlockFieldFlags Flags;
1690
1691 // CaptureStrKind::Merged should be passed only when the operations and the
1692 // flags are the same for copy and dispose.
1693 assert((StrKind != CaptureStrKind::Merged ||
1694 (Cap.CopyKind == Cap.DisposeKind &&
1695 Cap.CopyFlags == Cap.DisposeFlags)) &&
1696 "different operations and flags");
1697
1698 if (StrKind == CaptureStrKind::DisposeHelper) {
1699 Kind = Cap.DisposeKind;
1700 Flags = Cap.DisposeFlags;
1701 } else {
1702 Kind = Cap.CopyKind;
1703 Flags = Cap.CopyFlags;
1704 }
1705
1706 switch (Kind) {
1707 case BlockCaptureEntityKind::CXXRecord: {
1708 Str += "c";
1709 SmallString<256> TyStr;
1710 llvm::raw_svector_ostream Out(TyStr);
1711 CGM.getCXXABI().getMangleContext().mangleCanonicalTypeName(T: CaptureTy, Out);
1712 Str += llvm::to_string(Value: TyStr.size()) + TyStr.c_str();
1713 break;
1714 }
1715 case BlockCaptureEntityKind::ARCWeak:
1716 Str += "w";
1717 break;
1718 case BlockCaptureEntityKind::ARCStrong:
1719 Str += "s";
1720 break;
1721 case BlockCaptureEntityKind::BlockObject: {
1722 const VarDecl *Var = CI.getVariable();
1723 unsigned F = Flags.getBitMask();
1724 if (F & BLOCK_FIELD_IS_BYREF) {
1725 Str += "r";
1726 if (F & BLOCK_FIELD_IS_WEAK)
1727 Str += "w";
1728 else {
1729 // If CaptureStrKind::Merged is passed, check both the copy expression
1730 // and the destructor.
1731 if (StrKind != CaptureStrKind::DisposeHelper) {
1732 if (Ctx.getBlockVarCopyInit(VD: Var).canThrow())
1733 Str += "c";
1734 }
1735 if (StrKind != CaptureStrKind::CopyHelper) {
1736 if (CodeGenFunction::cxxDestructorCanThrow(T: CaptureTy))
1737 Str += "d";
1738 }
1739 }
1740 } else {
1741 assert((F & BLOCK_FIELD_IS_OBJECT) && "unexpected flag value");
1742 if (F == BLOCK_FIELD_IS_BLOCK)
1743 Str += "b";
1744 else
1745 Str += "o";
1746 }
1747 break;
1748 }
1749 case BlockCaptureEntityKind::NonTrivialCStruct: {
1750 bool IsVolatile = CaptureTy.isVolatileQualified();
1751 CharUnits Alignment = BlockAlignment.alignmentAtOffset(offset: Cap.getOffset());
1752
1753 Str += "n";
1754 std::string FuncStr;
1755 if (StrKind == CaptureStrKind::DisposeHelper)
1756 FuncStr = CodeGenFunction::getNonTrivialDestructorStr(
1757 QT: CaptureTy, Alignment, IsVolatile, Ctx);
1758 else
1759 // If CaptureStrKind::Merged is passed, use the copy constructor string.
1760 // It has all the information that the destructor string has.
1761 FuncStr = CodeGenFunction::getNonTrivialCopyConstructorStr(
1762 QT: CaptureTy, Alignment, IsVolatile, Ctx);
1763 // The underscore is necessary here because non-trivial copy constructor
1764 // and destructor strings can start with a number.
1765 Str += llvm::to_string(Value: FuncStr.size()) + "_" + FuncStr;
1766 break;
1767 }
1768 case BlockCaptureEntityKind::None:
1769 break;
1770 }
1771
1772 return Str;
1773}
1774
1775static std::string getCopyDestroyHelperFuncName(
1776 const SmallVectorImpl<CGBlockInfo::Capture> &Captures,
1777 CharUnits BlockAlignment, CaptureStrKind StrKind, CodeGenModule &CGM) {
1778 assert((StrKind == CaptureStrKind::CopyHelper ||
1779 StrKind == CaptureStrKind::DisposeHelper) &&
1780 "unexpected CaptureStrKind");
1781 std::string Name = StrKind == CaptureStrKind::CopyHelper
1782 ? "__copy_helper_block_"
1783 : "__destroy_helper_block_";
1784 if (CGM.getLangOpts().Exceptions)
1785 Name += "e";
1786 if (CGM.getCodeGenOpts().ObjCAutoRefCountExceptions)
1787 Name += "a";
1788 Name += llvm::to_string(Value: BlockAlignment.getQuantity()) + "_";
1789
1790 for (auto &Cap : Captures) {
1791 if (Cap.isConstantOrTrivial())
1792 continue;
1793 Name += llvm::to_string(Value: Cap.getOffset().getQuantity());
1794 Name += getBlockCaptureStr(Cap, StrKind, BlockAlignment, CGM);
1795 }
1796
1797 return Name;
1798}
1799
1800static void pushCaptureCleanup(BlockCaptureEntityKind CaptureKind,
1801 Address Field, QualType CaptureType,
1802 BlockFieldFlags Flags, bool ForCopyHelper,
1803 VarDecl *Var, CodeGenFunction &CGF) {
1804 bool EHOnly = ForCopyHelper;
1805
1806 switch (CaptureKind) {
1807 case BlockCaptureEntityKind::CXXRecord:
1808 case BlockCaptureEntityKind::ARCWeak:
1809 case BlockCaptureEntityKind::NonTrivialCStruct:
1810 case BlockCaptureEntityKind::ARCStrong: {
1811 if (CaptureType.isDestructedType() &&
1812 (!EHOnly || CGF.needsEHCleanup(kind: CaptureType.isDestructedType()))) {
1813 CodeGenFunction::Destroyer *Destroyer =
1814 CaptureKind == BlockCaptureEntityKind::ARCStrong
1815 ? CodeGenFunction::destroyARCStrongImprecise
1816 : CGF.getDestroyer(destructionKind: CaptureType.isDestructedType());
1817 CleanupKind Kind =
1818 EHOnly ? EHCleanup
1819 : CGF.getCleanupKind(kind: CaptureType.isDestructedType());
1820 CGF.pushDestroy(kind: Kind, addr: Field, type: CaptureType, destroyer: Destroyer, useEHCleanupForArray: Kind & EHCleanup);
1821 }
1822 break;
1823 }
1824 case BlockCaptureEntityKind::BlockObject: {
1825 if (!EHOnly || CGF.getLangOpts().Exceptions) {
1826 CleanupKind Kind = EHOnly ? EHCleanup : NormalAndEHCleanup;
1827 // Calls to _Block_object_dispose along the EH path in the copy helper
1828 // function don't throw as newly-copied __block variables always have a
1829 // reference count of 2.
1830 bool CanThrow =
1831 !ForCopyHelper && CGF.cxxDestructorCanThrow(T: CaptureType);
1832 CGF.enterByrefCleanup(Kind, Addr: Field, Flags, /*LoadBlockVarAddr*/ true,
1833 CanThrow);
1834 }
1835 break;
1836 }
1837 case BlockCaptureEntityKind::None:
1838 break;
1839 }
1840}
1841
1842static void setBlockHelperAttributesVisibility(bool CapturesNonExternalType,
1843 llvm::Function *Fn,
1844 const CGFunctionInfo &FI,
1845 CodeGenModule &CGM) {
1846 if (CapturesNonExternalType) {
1847 CGM.SetInternalFunctionAttributes(GD: GlobalDecl(), F: Fn, FI);
1848 } else {
1849 Fn->setVisibility(llvm::GlobalValue::HiddenVisibility);
1850 Fn->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
1851 CGM.SetLLVMFunctionAttributes(GD: GlobalDecl(), Info: FI, F: Fn, /*IsThunk=*/false);
1852 CGM.SetLLVMFunctionAttributesForDefinition(D: nullptr, F: Fn);
1853 }
1854}
1855/// Generate the copy-helper function for a block closure object:
1856/// static void block_copy_helper(block_t *dst, block_t *src);
1857/// The runtime will have previously initialized 'dst' by doing a
1858/// bit-copy of 'src'.
1859///
1860/// Note that this copies an entire block closure object to the heap;
1861/// it should not be confused with a 'byref copy helper', which moves
1862/// the contents of an individual __block variable to the heap.
1863llvm::Constant *
1864CodeGenFunction::GenerateCopyHelperFunction(const CGBlockInfo &blockInfo) {
1865 std::string FuncName = getCopyDestroyHelperFuncName(
1866 Captures: blockInfo.SortedCaptures, BlockAlignment: blockInfo.BlockAlign,
1867 StrKind: CaptureStrKind::CopyHelper, CGM);
1868
1869 if (llvm::GlobalValue *Func = CGM.getModule().getNamedValue(Name: FuncName))
1870 return Func;
1871
1872 ASTContext &C = getContext();
1873
1874 QualType ReturnTy = C.VoidTy;
1875
1876 FunctionArgList args;
1877 ImplicitParamDecl DstDecl(C, C.VoidPtrTy, ImplicitParamKind::Other);
1878 args.push_back(&DstDecl);
1879 ImplicitParamDecl SrcDecl(C, C.VoidPtrTy, ImplicitParamKind::Other);
1880 args.push_back(&SrcDecl);
1881
1882 const CGFunctionInfo &FI =
1883 CGM.getTypes().arrangeBuiltinFunctionDeclaration(resultType: ReturnTy, args);
1884
1885 // FIXME: it would be nice if these were mergeable with things with
1886 // identical semantics.
1887 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(Info: FI);
1888
1889 llvm::Function *Fn =
1890 llvm::Function::Create(Ty: LTy, Linkage: llvm::GlobalValue::LinkOnceODRLinkage,
1891 N: FuncName, M: &CGM.getModule());
1892 if (CGM.supportsCOMDAT())
1893 Fn->setComdat(CGM.getModule().getOrInsertComdat(Name: FuncName));
1894
1895 SmallVector<QualType, 2> ArgTys;
1896 ArgTys.push_back(Elt: C.VoidPtrTy);
1897 ArgTys.push_back(Elt: C.VoidPtrTy);
1898
1899 setBlockHelperAttributesVisibility(CapturesNonExternalType: blockInfo.CapturesNonExternalType, Fn, FI,
1900 CGM);
1901 StartFunction(GD: GlobalDecl(), RetTy: ReturnTy, Fn, FnInfo: FI, Args: args);
1902 auto AL = ApplyDebugLocation::CreateArtificial(CGF&: *this);
1903
1904 Address src = GetAddrOfLocalVar(&SrcDecl);
1905 src = Address(Builder.CreateLoad(Addr: src), blockInfo.StructureType,
1906 blockInfo.BlockAlign);
1907
1908 Address dst = GetAddrOfLocalVar(&DstDecl);
1909 dst = Address(Builder.CreateLoad(Addr: dst), blockInfo.StructureType,
1910 blockInfo.BlockAlign);
1911
1912 for (auto &capture : blockInfo.SortedCaptures) {
1913 if (capture.isConstantOrTrivial())
1914 continue;
1915
1916 const BlockDecl::Capture &CI = *capture.Cap;
1917 QualType captureType = CI.getVariable()->getType();
1918 BlockFieldFlags flags = capture.CopyFlags;
1919
1920 unsigned index = capture.getIndex();
1921 Address srcField = Builder.CreateStructGEP(Addr: src, Index: index);
1922 Address dstField = Builder.CreateStructGEP(Addr: dst, Index: index);
1923
1924 switch (capture.CopyKind) {
1925 case BlockCaptureEntityKind::CXXRecord:
1926 // If there's an explicit copy expression, we do that.
1927 assert(CI.getCopyExpr() && "copy expression for variable is missing");
1928 EmitSynthesizedCXXCopyCtor(Dest: dstField, Src: srcField, Exp: CI.getCopyExpr());
1929 break;
1930 case BlockCaptureEntityKind::ARCWeak:
1931 EmitARCCopyWeak(dst: dstField, src: srcField);
1932 break;
1933 case BlockCaptureEntityKind::NonTrivialCStruct: {
1934 // If this is a C struct that requires non-trivial copy construction,
1935 // emit a call to its copy constructor.
1936 QualType varType = CI.getVariable()->getType();
1937 callCStructCopyConstructor(Dst: MakeAddrLValue(Addr: dstField, T: varType),
1938 Src: MakeAddrLValue(Addr: srcField, T: varType));
1939 break;
1940 }
1941 case BlockCaptureEntityKind::ARCStrong: {
1942 llvm::Value *srcValue = Builder.CreateLoad(Addr: srcField, Name: "blockcopy.src");
1943 // At -O0, store null into the destination field (so that the
1944 // storeStrong doesn't over-release) and then call storeStrong.
1945 // This is a workaround to not having an initStrong call.
1946 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1947 auto *ty = cast<llvm::PointerType>(Val: srcValue->getType());
1948 llvm::Value *null = llvm::ConstantPointerNull::get(T: ty);
1949 Builder.CreateStore(Val: null, Addr: dstField);
1950 EmitARCStoreStrongCall(addr: dstField, value: srcValue, resultIgnored: true);
1951
1952 // With optimization enabled, take advantage of the fact that
1953 // the blocks runtime guarantees a memcpy of the block data, and
1954 // just emit a retain of the src field.
1955 } else {
1956 EmitARCRetainNonBlock(value: srcValue);
1957
1958 // Unless EH cleanup is required, we don't need this anymore, so kill
1959 // it. It's not quite worth the annoyance to avoid creating it in the
1960 // first place.
1961 if (!needsEHCleanup(kind: captureType.isDestructedType()))
1962 cast<llvm::Instruction>(Val: dstField.getPointer())->eraseFromParent();
1963 }
1964 break;
1965 }
1966 case BlockCaptureEntityKind::BlockObject: {
1967 llvm::Value *srcValue = Builder.CreateLoad(Addr: srcField, Name: "blockcopy.src");
1968 llvm::Value *dstAddr = dstField.getPointer();
1969 llvm::Value *args[] = {
1970 dstAddr, srcValue, llvm::ConstantInt::get(Ty: Int32Ty, V: flags.getBitMask())
1971 };
1972
1973 if (CI.isByRef() && C.getBlockVarCopyInit(VD: CI.getVariable()).canThrow())
1974 EmitRuntimeCallOrInvoke(callee: CGM.getBlockObjectAssign(), args);
1975 else
1976 EmitNounwindRuntimeCall(callee: CGM.getBlockObjectAssign(), args);
1977 break;
1978 }
1979 case BlockCaptureEntityKind::None:
1980 continue;
1981 }
1982
1983 // Ensure that we destroy the copied object if an exception is thrown later
1984 // in the helper function.
1985 pushCaptureCleanup(CaptureKind: capture.CopyKind, Field: dstField, CaptureType: captureType, Flags: flags,
1986 /*ForCopyHelper*/ true, Var: CI.getVariable(), CGF&: *this);
1987 }
1988
1989 FinishFunction();
1990
1991 return Fn;
1992}
1993
1994static BlockFieldFlags
1995getBlockFieldFlagsForObjCObjectPointer(const BlockDecl::Capture &CI,
1996 QualType T) {
1997 BlockFieldFlags Flags = BLOCK_FIELD_IS_OBJECT;
1998 if (T->isBlockPointerType())
1999 Flags = BLOCK_FIELD_IS_BLOCK;
2000 return Flags;
2001}
2002
2003static std::pair<BlockCaptureEntityKind, BlockFieldFlags>
2004computeDestroyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T,
2005 const LangOptions &LangOpts) {
2006 if (CI.isEscapingByref()) {
2007 BlockFieldFlags Flags = BLOCK_FIELD_IS_BYREF;
2008 if (T.isObjCGCWeak())
2009 Flags |= BLOCK_FIELD_IS_WEAK;
2010 return std::make_pair(x: BlockCaptureEntityKind::BlockObject, y&: Flags);
2011 }
2012
2013 switch (T.isDestructedType()) {
2014 case QualType::DK_cxx_destructor:
2015 return std::make_pair(x: BlockCaptureEntityKind::CXXRecord, y: BlockFieldFlags());
2016 case QualType::DK_objc_strong_lifetime:
2017 // Use objc_storeStrong for __strong direct captures; the
2018 // dynamic tools really like it when we do this.
2019 return std::make_pair(x: BlockCaptureEntityKind::ARCStrong,
2020 y: getBlockFieldFlagsForObjCObjectPointer(CI, T));
2021 case QualType::DK_objc_weak_lifetime:
2022 // Support __weak direct captures.
2023 return std::make_pair(x: BlockCaptureEntityKind::ARCWeak,
2024 y: getBlockFieldFlagsForObjCObjectPointer(CI, T));
2025 case QualType::DK_nontrivial_c_struct:
2026 return std::make_pair(x: BlockCaptureEntityKind::NonTrivialCStruct,
2027 y: BlockFieldFlags());
2028 case QualType::DK_none: {
2029 // Non-ARC captures are strong, and we need to use _Block_object_dispose.
2030 // But honor the inert __unsafe_unretained qualifier, which doesn't actually
2031 // make it into the type system.
2032 if (T->isObjCRetainableType() && !T.getQualifiers().hasObjCLifetime() &&
2033 !LangOpts.ObjCAutoRefCount && !T->isObjCInertUnsafeUnretainedType())
2034 return std::make_pair(x: BlockCaptureEntityKind::BlockObject,
2035 y: getBlockFieldFlagsForObjCObjectPointer(CI, T));
2036 // Otherwise, we have nothing to do.
2037 return std::make_pair(x: BlockCaptureEntityKind::None, y: BlockFieldFlags());
2038 }
2039 }
2040 llvm_unreachable("after exhaustive DestructionKind switch");
2041}
2042
2043/// Generate the destroy-helper function for a block closure object:
2044/// static void block_destroy_helper(block_t *theBlock);
2045///
2046/// Note that this destroys a heap-allocated block closure object;
2047/// it should not be confused with a 'byref destroy helper', which
2048/// destroys the heap-allocated contents of an individual __block
2049/// variable.
2050llvm::Constant *
2051CodeGenFunction::GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo) {
2052 std::string FuncName = getCopyDestroyHelperFuncName(
2053 Captures: blockInfo.SortedCaptures, BlockAlignment: blockInfo.BlockAlign,
2054 StrKind: CaptureStrKind::DisposeHelper, CGM);
2055
2056 if (llvm::GlobalValue *Func = CGM.getModule().getNamedValue(Name: FuncName))
2057 return Func;
2058
2059 ASTContext &C = getContext();
2060
2061 QualType ReturnTy = C.VoidTy;
2062
2063 FunctionArgList args;
2064 ImplicitParamDecl SrcDecl(C, C.VoidPtrTy, ImplicitParamKind::Other);
2065 args.push_back(&SrcDecl);
2066
2067 const CGFunctionInfo &FI =
2068 CGM.getTypes().arrangeBuiltinFunctionDeclaration(resultType: ReturnTy, args);
2069
2070 // FIXME: We'd like to put these into a mergable by content, with
2071 // internal linkage.
2072 llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(Info: FI);
2073
2074 llvm::Function *Fn =
2075 llvm::Function::Create(Ty: LTy, Linkage: llvm::GlobalValue::LinkOnceODRLinkage,
2076 N: FuncName, M: &CGM.getModule());
2077 if (CGM.supportsCOMDAT())
2078 Fn->setComdat(CGM.getModule().getOrInsertComdat(Name: FuncName));
2079
2080 SmallVector<QualType, 1> ArgTys;
2081 ArgTys.push_back(Elt: C.VoidPtrTy);
2082
2083 setBlockHelperAttributesVisibility(CapturesNonExternalType: blockInfo.CapturesNonExternalType, Fn, FI,
2084 CGM);
2085 StartFunction(GD: GlobalDecl(), RetTy: ReturnTy, Fn, FnInfo: FI, Args: args);
2086 markAsIgnoreThreadCheckingAtRuntime(Fn);
2087
2088 auto AL = ApplyDebugLocation::CreateArtificial(CGF&: *this);
2089
2090 Address src = GetAddrOfLocalVar(&SrcDecl);
2091 src = Address(Builder.CreateLoad(Addr: src), blockInfo.StructureType,
2092 blockInfo.BlockAlign);
2093
2094 CodeGenFunction::RunCleanupsScope cleanups(*this);
2095
2096 for (auto &capture : blockInfo.SortedCaptures) {
2097 if (capture.isConstantOrTrivial())
2098 continue;
2099
2100 const BlockDecl::Capture &CI = *capture.Cap;
2101 BlockFieldFlags flags = capture.DisposeFlags;
2102
2103 Address srcField = Builder.CreateStructGEP(Addr: src, Index: capture.getIndex());
2104
2105 pushCaptureCleanup(capture.DisposeKind, srcField,
2106 CI.getVariable()->getType(), flags,
2107 /*ForCopyHelper*/ false, CI.getVariable(), *this);
2108 }
2109
2110 cleanups.ForceCleanup();
2111
2112 FinishFunction();
2113
2114 return Fn;
2115}
2116
2117namespace {
2118
2119/// Emits the copy/dispose helper functions for a __block object of id type.
2120class ObjectByrefHelpers final : public BlockByrefHelpers {
2121 BlockFieldFlags Flags;
2122
2123public:
2124 ObjectByrefHelpers(CharUnits alignment, BlockFieldFlags flags)
2125 : BlockByrefHelpers(alignment), Flags(flags) {}
2126
2127 void emitCopy(CodeGenFunction &CGF, Address destField,
2128 Address srcField) override {
2129 destField = destField.withElementType(ElemTy: CGF.Int8Ty);
2130
2131 srcField = srcField.withElementType(ElemTy: CGF.Int8PtrTy);
2132 llvm::Value *srcValue = CGF.Builder.CreateLoad(Addr: srcField);
2133
2134 unsigned flags = (Flags | BLOCK_BYREF_CALLER).getBitMask();
2135
2136 llvm::Value *flagsVal = llvm::ConstantInt::get(Ty: CGF.Int32Ty, V: flags);
2137 llvm::FunctionCallee fn = CGF.CGM.getBlockObjectAssign();
2138
2139 llvm::Value *args[] = { destField.getPointer(), srcValue, flagsVal };
2140 CGF.EmitNounwindRuntimeCall(callee: fn, args);
2141 }
2142
2143 void emitDispose(CodeGenFunction &CGF, Address field) override {
2144 field = field.withElementType(ElemTy: CGF.Int8PtrTy);
2145 llvm::Value *value = CGF.Builder.CreateLoad(Addr: field);
2146
2147 CGF.BuildBlockRelease(DeclPtr: value, flags: Flags | BLOCK_BYREF_CALLER, CanThrow: false);
2148 }
2149
2150 void profileImpl(llvm::FoldingSetNodeID &id) const override {
2151 id.AddInteger(I: Flags.getBitMask());
2152 }
2153};
2154
2155/// Emits the copy/dispose helpers for an ARC __block __weak variable.
2156class ARCWeakByrefHelpers final : public BlockByrefHelpers {
2157public:
2158 ARCWeakByrefHelpers(CharUnits alignment) : BlockByrefHelpers(alignment) {}
2159
2160 void emitCopy(CodeGenFunction &CGF, Address destField,
2161 Address srcField) override {
2162 CGF.EmitARCMoveWeak(dst: destField, src: srcField);
2163 }
2164
2165 void emitDispose(CodeGenFunction &CGF, Address field) override {
2166 CGF.EmitARCDestroyWeak(addr: field);
2167 }
2168
2169 void profileImpl(llvm::FoldingSetNodeID &id) const override {
2170 // 0 is distinguishable from all pointers and byref flags
2171 id.AddInteger(I: 0);
2172 }
2173};
2174
2175/// Emits the copy/dispose helpers for an ARC __block __strong variable
2176/// that's not of block-pointer type.
2177class ARCStrongByrefHelpers final : public BlockByrefHelpers {
2178public:
2179 ARCStrongByrefHelpers(CharUnits alignment) : BlockByrefHelpers(alignment) {}
2180
2181 void emitCopy(CodeGenFunction &CGF, Address destField,
2182 Address srcField) override {
2183 // Do a "move" by copying the value and then zeroing out the old
2184 // variable.
2185
2186 llvm::Value *value = CGF.Builder.CreateLoad(Addr: srcField);
2187
2188 llvm::Value *null =
2189 llvm::ConstantPointerNull::get(T: cast<llvm::PointerType>(Val: value->getType()));
2190
2191 if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0) {
2192 CGF.Builder.CreateStore(Val: null, Addr: destField);
2193 CGF.EmitARCStoreStrongCall(addr: destField, value, /*ignored*/ resultIgnored: true);
2194 CGF.EmitARCStoreStrongCall(addr: srcField, value: null, /*ignored*/ resultIgnored: true);
2195 return;
2196 }
2197 CGF.Builder.CreateStore(Val: value, Addr: destField);
2198 CGF.Builder.CreateStore(Val: null, Addr: srcField);
2199 }
2200
2201 void emitDispose(CodeGenFunction &CGF, Address field) override {
2202 CGF.EmitARCDestroyStrong(addr: field, precise: ARCImpreciseLifetime);
2203 }
2204
2205 void profileImpl(llvm::FoldingSetNodeID &id) const override {
2206 // 1 is distinguishable from all pointers and byref flags
2207 id.AddInteger(I: 1);
2208 }
2209};
2210
2211/// Emits the copy/dispose helpers for an ARC __block __strong
2212/// variable that's of block-pointer type.
2213class ARCStrongBlockByrefHelpers final : public BlockByrefHelpers {
2214public:
2215 ARCStrongBlockByrefHelpers(CharUnits alignment)
2216 : BlockByrefHelpers(alignment) {}
2217
2218 void emitCopy(CodeGenFunction &CGF, Address destField,
2219 Address srcField) override {
2220 // Do the copy with objc_retainBlock; that's all that
2221 // _Block_object_assign would do anyway, and we'd have to pass the
2222 // right arguments to make sure it doesn't get no-op'ed.
2223 llvm::Value *oldValue = CGF.Builder.CreateLoad(Addr: srcField);
2224 llvm::Value *copy = CGF.EmitARCRetainBlock(value: oldValue, /*mandatory*/ true);
2225 CGF.Builder.CreateStore(Val: copy, Addr: destField);
2226 }
2227
2228 void emitDispose(CodeGenFunction &CGF, Address field) override {
2229 CGF.EmitARCDestroyStrong(addr: field, precise: ARCImpreciseLifetime);
2230 }
2231
2232 void profileImpl(llvm::FoldingSetNodeID &id) const override {
2233 // 2 is distinguishable from all pointers and byref flags
2234 id.AddInteger(I: 2);
2235 }
2236};
2237
2238/// Emits the copy/dispose helpers for a __block variable with a
2239/// nontrivial copy constructor or destructor.
2240class CXXByrefHelpers final : public BlockByrefHelpers {
2241 QualType VarType;
2242 const Expr *CopyExpr;
2243
2244public:
2245 CXXByrefHelpers(CharUnits alignment, QualType type,
2246 const Expr *copyExpr)
2247 : BlockByrefHelpers(alignment), VarType(type), CopyExpr(copyExpr) {}
2248
2249 bool needsCopy() const override { return CopyExpr != nullptr; }
2250 void emitCopy(CodeGenFunction &CGF, Address destField,
2251 Address srcField) override {
2252 if (!CopyExpr) return;
2253 CGF.EmitSynthesizedCXXCopyCtor(Dest: destField, Src: srcField, Exp: CopyExpr);
2254 }
2255
2256 void emitDispose(CodeGenFunction &CGF, Address field) override {
2257 EHScopeStack::stable_iterator cleanupDepth = CGF.EHStack.stable_begin();
2258 CGF.PushDestructorCleanup(VarType, field);
2259 CGF.PopCleanupBlocks(OldCleanupStackSize: cleanupDepth);
2260 }
2261
2262 void profileImpl(llvm::FoldingSetNodeID &id) const override {
2263 id.AddPointer(VarType.getCanonicalType().getAsOpaquePtr());
2264 }
2265};
2266
2267/// Emits the copy/dispose helpers for a __block variable that is a non-trivial
2268/// C struct.
2269class NonTrivialCStructByrefHelpers final : public BlockByrefHelpers {
2270 QualType VarType;
2271
2272public:
2273 NonTrivialCStructByrefHelpers(CharUnits alignment, QualType type)
2274 : BlockByrefHelpers(alignment), VarType(type) {}
2275
2276 void emitCopy(CodeGenFunction &CGF, Address destField,
2277 Address srcField) override {
2278 CGF.callCStructMoveConstructor(CGF.MakeAddrLValue(destField, VarType),
2279 CGF.MakeAddrLValue(srcField, VarType));
2280 }
2281
2282 bool needsDispose() const override {
2283 return VarType.isDestructedType();
2284 }
2285
2286 void emitDispose(CodeGenFunction &CGF, Address field) override {
2287 EHScopeStack::stable_iterator cleanupDepth = CGF.EHStack.stable_begin();
2288 CGF.pushDestroy(VarType.isDestructedType(), field, VarType);
2289 CGF.PopCleanupBlocks(OldCleanupStackSize: cleanupDepth);
2290 }
2291
2292 void profileImpl(llvm::FoldingSetNodeID &id) const override {
2293 id.AddPointer(VarType.getCanonicalType().getAsOpaquePtr());
2294 }
2295};
2296} // end anonymous namespace
2297
2298static llvm::Constant *
2299generateByrefCopyHelper(CodeGenFunction &CGF, const BlockByrefInfo &byrefInfo,
2300 BlockByrefHelpers &generator) {
2301 ASTContext &Context = CGF.getContext();
2302
2303 QualType ReturnTy = Context.VoidTy;
2304
2305 FunctionArgList args;
2306 ImplicitParamDecl Dst(Context, Context.VoidPtrTy, ImplicitParamKind::Other);
2307 args.push_back(&Dst);
2308
2309 ImplicitParamDecl Src(Context, Context.VoidPtrTy, ImplicitParamKind::Other);
2310 args.push_back(&Src);
2311
2312 const CGFunctionInfo &FI =
2313 CGF.CGM.getTypes().arrangeBuiltinFunctionDeclaration(resultType: ReturnTy, args);
2314
2315 llvm::FunctionType *LTy = CGF.CGM.getTypes().GetFunctionType(Info: FI);
2316
2317 // FIXME: We'd like to put these into a mergable by content, with
2318 // internal linkage.
2319 llvm::Function *Fn =
2320 llvm::Function::Create(Ty: LTy, Linkage: llvm::GlobalValue::InternalLinkage,
2321 N: "__Block_byref_object_copy_", M: &CGF.CGM.getModule());
2322
2323 SmallVector<QualType, 2> ArgTys;
2324 ArgTys.push_back(Elt: Context.VoidPtrTy);
2325 ArgTys.push_back(Elt: Context.VoidPtrTy);
2326
2327 CGF.CGM.SetInternalFunctionAttributes(GD: GlobalDecl(), F: Fn, FI);
2328
2329 CGF.StartFunction(GD: GlobalDecl(), RetTy: ReturnTy, Fn, FnInfo: FI, Args: args);
2330 // Create a scope with an artificial location for the body of this function.
2331 auto AL = ApplyDebugLocation::CreateArtificial(CGF);
2332
2333 if (generator.needsCopy()) {
2334 // dst->x
2335 Address destField = CGF.GetAddrOfLocalVar(&Dst);
2336 destField = Address(CGF.Builder.CreateLoad(Addr: destField), byrefInfo.Type,
2337 byrefInfo.ByrefAlignment);
2338 destField =
2339 CGF.emitBlockByrefAddress(baseAddr: destField, info: byrefInfo, followForward: false, name: "dest-object");
2340
2341 // src->x
2342 Address srcField = CGF.GetAddrOfLocalVar(&Src);
2343 srcField = Address(CGF.Builder.CreateLoad(Addr: srcField), byrefInfo.Type,
2344 byrefInfo.ByrefAlignment);
2345 srcField =
2346 CGF.emitBlockByrefAddress(baseAddr: srcField, info: byrefInfo, followForward: false, name: "src-object");
2347
2348 generator.emitCopy(CGF, dest: destField, src: srcField);
2349 }
2350
2351 CGF.FinishFunction();
2352
2353 return Fn;
2354}
2355
2356/// Build the copy helper for a __block variable.
2357static llvm::Constant *buildByrefCopyHelper(CodeGenModule &CGM,
2358 const BlockByrefInfo &byrefInfo,
2359 BlockByrefHelpers &generator) {
2360 CodeGenFunction CGF(CGM);
2361 return generateByrefCopyHelper(CGF, byrefInfo, generator);
2362}
2363
2364/// Generate code for a __block variable's dispose helper.
2365static llvm::Constant *
2366generateByrefDisposeHelper(CodeGenFunction &CGF,
2367 const BlockByrefInfo &byrefInfo,
2368 BlockByrefHelpers &generator) {
2369 ASTContext &Context = CGF.getContext();
2370 QualType R = Context.VoidTy;
2371
2372 FunctionArgList args;
2373 ImplicitParamDecl Src(CGF.getContext(), Context.VoidPtrTy,
2374 ImplicitParamKind::Other);
2375 args.push_back(&Src);
2376
2377 const CGFunctionInfo &FI =
2378 CGF.CGM.getTypes().arrangeBuiltinFunctionDeclaration(resultType: R, args);
2379
2380 llvm::FunctionType *LTy = CGF.CGM.getTypes().GetFunctionType(Info: FI);
2381
2382 // FIXME: We'd like to put these into a mergable by content, with
2383 // internal linkage.
2384 llvm::Function *Fn =
2385 llvm::Function::Create(Ty: LTy, Linkage: llvm::GlobalValue::InternalLinkage,
2386 N: "__Block_byref_object_dispose_",
2387 M: &CGF.CGM.getModule());
2388
2389 SmallVector<QualType, 1> ArgTys;
2390 ArgTys.push_back(Elt: Context.VoidPtrTy);
2391
2392 CGF.CGM.SetInternalFunctionAttributes(GD: GlobalDecl(), F: Fn, FI);
2393
2394 CGF.StartFunction(GD: GlobalDecl(), RetTy: R, Fn, FnInfo: FI, Args: args);
2395 // Create a scope with an artificial location for the body of this function.
2396 auto AL = ApplyDebugLocation::CreateArtificial(CGF);
2397
2398 if (generator.needsDispose()) {
2399 Address addr = CGF.GetAddrOfLocalVar(&Src);
2400 addr = Address(CGF.Builder.CreateLoad(Addr: addr), byrefInfo.Type,
2401 byrefInfo.ByrefAlignment);
2402 addr = CGF.emitBlockByrefAddress(baseAddr: addr, info: byrefInfo, followForward: false, name: "object");
2403
2404 generator.emitDispose(CGF, field: addr);
2405 }
2406
2407 CGF.FinishFunction();
2408
2409 return Fn;
2410}
2411
2412/// Build the dispose helper for a __block variable.
2413static llvm::Constant *buildByrefDisposeHelper(CodeGenModule &CGM,
2414 const BlockByrefInfo &byrefInfo,
2415 BlockByrefHelpers &generator) {
2416 CodeGenFunction CGF(CGM);
2417 return generateByrefDisposeHelper(CGF, byrefInfo, generator);
2418}
2419
2420/// Lazily build the copy and dispose helpers for a __block variable
2421/// with the given information.
2422template <class T>
2423static T *buildByrefHelpers(CodeGenModule &CGM, const BlockByrefInfo &byrefInfo,
2424 T &&generator) {
2425 llvm::FoldingSetNodeID id;
2426 generator.Profile(id);
2427
2428 void *insertPos;
2429 BlockByrefHelpers *node
2430 = CGM.ByrefHelpersCache.FindNodeOrInsertPos(ID: id, InsertPos&: insertPos);
2431 if (node) return static_cast<T*>(node);
2432
2433 generator.CopyHelper = buildByrefCopyHelper(CGM, byrefInfo, generator);
2434 generator.DisposeHelper = buildByrefDisposeHelper(CGM, byrefInfo, generator);
2435
2436 T *copy = new (CGM.getContext()) T(std::forward<T>(generator));
2437 CGM.ByrefHelpersCache.InsertNode(copy, insertPos);
2438 return copy;
2439}
2440
2441/// Build the copy and dispose helpers for the given __block variable
2442/// emission. Places the helpers in the global cache. Returns null
2443/// if no helpers are required.
2444BlockByrefHelpers *
2445CodeGenFunction::buildByrefHelpers(llvm::StructType &byrefType,
2446 const AutoVarEmission &emission) {
2447 const VarDecl &var = *emission.Variable;
2448 assert(var.isEscapingByref() &&
2449 "only escaping __block variables need byref helpers");
2450
2451 QualType type = var.getType();
2452
2453 auto &byrefInfo = getBlockByrefInfo(var: &var);
2454
2455 // The alignment we care about for the purposes of uniquing byref
2456 // helpers is the alignment of the actual byref value field.
2457 CharUnits valueAlignment =
2458 byrefInfo.ByrefAlignment.alignmentAtOffset(offset: byrefInfo.FieldOffset);
2459
2460 if (const CXXRecordDecl *record = type->getAsCXXRecordDecl()) {
2461 const Expr *copyExpr =
2462 CGM.getContext().getBlockVarCopyInit(VD: &var).getCopyExpr();
2463 if (!copyExpr && record->hasTrivialDestructor()) return nullptr;
2464
2465 return ::buildByrefHelpers(
2466 CGM, byrefInfo, generator: CXXByrefHelpers(valueAlignment, type, copyExpr));
2467 }
2468
2469 // If type is a non-trivial C struct type that is non-trivial to
2470 // destructly move or destroy, build the copy and dispose helpers.
2471 if (type.isNonTrivialToPrimitiveDestructiveMove() == QualType::PCK_Struct ||
2472 type.isDestructedType() == QualType::DK_nontrivial_c_struct)
2473 return ::buildByrefHelpers(
2474 CGM, byrefInfo, generator: NonTrivialCStructByrefHelpers(valueAlignment, type));
2475
2476 // Otherwise, if we don't have a retainable type, there's nothing to do.
2477 // that the runtime does extra copies.
2478 if (!type->isObjCRetainableType()) return nullptr;
2479
2480 Qualifiers qs = type.getQualifiers();
2481
2482 // If we have lifetime, that dominates.
2483 if (Qualifiers::ObjCLifetime lifetime = qs.getObjCLifetime()) {
2484 switch (lifetime) {
2485 case Qualifiers::OCL_None: llvm_unreachable("impossible");
2486
2487 // These are just bits as far as the runtime is concerned.
2488 case Qualifiers::OCL_ExplicitNone:
2489 case Qualifiers::OCL_Autoreleasing:
2490 return nullptr;
2491
2492 // Tell the runtime that this is ARC __weak, called by the
2493 // byref routines.
2494 case Qualifiers::OCL_Weak:
2495 return ::buildByrefHelpers(CGM, byrefInfo,
2496 generator: ARCWeakByrefHelpers(valueAlignment));
2497
2498 // ARC __strong __block variables need to be retained.
2499 case Qualifiers::OCL_Strong:
2500 // Block pointers need to be copied, and there's no direct
2501 // transfer possible.
2502 if (type->isBlockPointerType()) {
2503 return ::buildByrefHelpers(CGM, byrefInfo,
2504 generator: ARCStrongBlockByrefHelpers(valueAlignment));
2505
2506 // Otherwise, we transfer ownership of the retain from the stack
2507 // to the heap.
2508 } else {
2509 return ::buildByrefHelpers(CGM, byrefInfo,
2510 generator: ARCStrongByrefHelpers(valueAlignment));
2511 }
2512 }
2513 llvm_unreachable("fell out of lifetime switch!");
2514 }
2515
2516 BlockFieldFlags flags;
2517 if (type->isBlockPointerType()) {
2518 flags |= BLOCK_FIELD_IS_BLOCK;
2519 } else if (CGM.getContext().isObjCNSObjectType(Ty: type) ||
2520 type->isObjCObjectPointerType()) {
2521 flags |= BLOCK_FIELD_IS_OBJECT;
2522 } else {
2523 return nullptr;
2524 }
2525
2526 if (type.isObjCGCWeak())
2527 flags |= BLOCK_FIELD_IS_WEAK;
2528
2529 return ::buildByrefHelpers(CGM, byrefInfo,
2530 generator: ObjectByrefHelpers(valueAlignment, flags));
2531}
2532
2533Address CodeGenFunction::emitBlockByrefAddress(Address baseAddr,
2534 const VarDecl *var,
2535 bool followForward) {
2536 auto &info = getBlockByrefInfo(var);
2537 return emitBlockByrefAddress(baseAddr, info, followForward, var->getName());
2538}
2539
2540Address CodeGenFunction::emitBlockByrefAddress(Address baseAddr,
2541 const BlockByrefInfo &info,
2542 bool followForward,
2543 const llvm::Twine &name) {
2544 // Chase the forwarding address if requested.
2545 if (followForward) {
2546 Address forwardingAddr = Builder.CreateStructGEP(Addr: baseAddr, Index: 1, Name: "forwarding");
2547 baseAddr = Address(Builder.CreateLoad(Addr: forwardingAddr), info.Type,
2548 info.ByrefAlignment);
2549 }
2550
2551 return Builder.CreateStructGEP(Addr: baseAddr, Index: info.FieldIndex, Name: name);
2552}
2553
2554/// BuildByrefInfo - This routine changes a __block variable declared as T x
2555/// into:
2556///
2557/// struct {
2558/// void *__isa;
2559/// void *__forwarding;
2560/// int32_t __flags;
2561/// int32_t __size;
2562/// void *__copy_helper; // only if needed
2563/// void *__destroy_helper; // only if needed
2564/// void *__byref_variable_layout;// only if needed
2565/// char padding[X]; // only if needed
2566/// T x;
2567/// } x
2568///
2569const BlockByrefInfo &CodeGenFunction::getBlockByrefInfo(const VarDecl *D) {
2570 auto it = BlockByrefInfos.find(D);
2571 if (it != BlockByrefInfos.end())
2572 return it->second;
2573
2574 llvm::StructType *byrefType =
2575 llvm::StructType::create(getLLVMContext(),
2576 "struct.__block_byref_" + D->getNameAsString());
2577
2578 QualType Ty = D->getType();
2579
2580 CharUnits size;
2581 SmallVector<llvm::Type *, 8> types;
2582
2583 // void *__isa;
2584 types.push_back(Elt: VoidPtrTy);
2585 size += getPointerSize();
2586
2587 // void *__forwarding;
2588 types.push_back(Elt: VoidPtrTy);
2589 size += getPointerSize();
2590
2591 // int32_t __flags;
2592 types.push_back(Elt: Int32Ty);
2593 size += CharUnits::fromQuantity(Quantity: 4);
2594
2595 // int32_t __size;
2596 types.push_back(Elt: Int32Ty);
2597 size += CharUnits::fromQuantity(Quantity: 4);
2598
2599 // Note that this must match *exactly* the logic in buildByrefHelpers.
2600 bool hasCopyAndDispose = getContext().BlockRequiresCopying(Ty, D);
2601 if (hasCopyAndDispose) {
2602 /// void *__copy_helper;
2603 types.push_back(Elt: VoidPtrTy);
2604 size += getPointerSize();
2605
2606 /// void *__destroy_helper;
2607 types.push_back(Elt: VoidPtrTy);
2608 size += getPointerSize();
2609 }
2610
2611 bool HasByrefExtendedLayout = false;
2612 Qualifiers::ObjCLifetime Lifetime = Qualifiers::OCL_None;
2613 if (getContext().getByrefLifetime(Ty, Lifetime, HasByrefExtendedLayout) &&
2614 HasByrefExtendedLayout) {
2615 /// void *__byref_variable_layout;
2616 types.push_back(Elt: VoidPtrTy);
2617 size += CharUnits::fromQuantity(Quantity: PointerSizeInBytes);
2618 }
2619
2620 // T x;
2621 llvm::Type *varTy = ConvertTypeForMem(T: Ty);
2622
2623 bool packed = false;
2624 CharUnits varAlign = getContext().getDeclAlign(D);
2625 CharUnits varOffset = size.alignTo(Align: varAlign);
2626
2627 // We may have to insert padding.
2628 if (varOffset != size) {
2629 llvm::Type *paddingTy =
2630 llvm::ArrayType::get(ElementType: Int8Ty, NumElements: (varOffset - size).getQuantity());
2631
2632 types.push_back(Elt: paddingTy);
2633 size = varOffset;
2634
2635 // Conversely, we might have to prevent LLVM from inserting padding.
2636 } else if (CGM.getDataLayout().getABITypeAlign(Ty: varTy) >
2637 uint64_t(varAlign.getQuantity())) {
2638 packed = true;
2639 }
2640 types.push_back(Elt: varTy);
2641
2642 byrefType->setBody(Elements: types, isPacked: packed);
2643
2644 BlockByrefInfo info;
2645 info.Type = byrefType;
2646 info.FieldIndex = types.size() - 1;
2647 info.FieldOffset = varOffset;
2648 info.ByrefAlignment = std::max(varAlign, getPointerAlign());
2649
2650 auto pair = BlockByrefInfos.insert({D, info});
2651 assert(pair.second && "info was inserted recursively?");
2652 return pair.first->second;
2653}
2654
2655/// Initialize the structural components of a __block variable, i.e.
2656/// everything but the actual object.
2657void CodeGenFunction::emitByrefStructureInit(const AutoVarEmission &emission) {
2658 // Find the address of the local.
2659 Address addr = emission.Addr;
2660
2661 // That's an alloca of the byref structure type.
2662 llvm::StructType *byrefType = cast<llvm::StructType>(Val: addr.getElementType());
2663
2664 unsigned nextHeaderIndex = 0;
2665 CharUnits nextHeaderOffset;
2666 auto storeHeaderField = [&](llvm::Value *value, CharUnits fieldSize,
2667 const Twine &name) {
2668 auto fieldAddr = Builder.CreateStructGEP(Addr: addr, Index: nextHeaderIndex, Name: name);
2669 Builder.CreateStore(Val: value, Addr: fieldAddr);
2670
2671 nextHeaderIndex++;
2672 nextHeaderOffset += fieldSize;
2673 };
2674
2675 // Build the byref helpers if necessary. This is null if we don't need any.
2676 BlockByrefHelpers *helpers = buildByrefHelpers(byrefType&: *byrefType, emission);
2677
2678 const VarDecl &D = *emission.Variable;
2679 QualType type = D.getType();
2680
2681 bool HasByrefExtendedLayout = false;
2682 Qualifiers::ObjCLifetime ByrefLifetime = Qualifiers::OCL_None;
2683 bool ByRefHasLifetime =
2684 getContext().getByrefLifetime(Ty: type, Lifetime&: ByrefLifetime, HasByrefExtendedLayout);
2685
2686 llvm::Value *V;
2687
2688 // Initialize the 'isa', which is just 0 or 1.
2689 int isa = 0;
2690 if (type.isObjCGCWeak())
2691 isa = 1;
2692 V = Builder.CreateIntToPtr(V: Builder.getInt32(C: isa), DestTy: Int8PtrTy, Name: "isa");
2693 storeHeaderField(V, getPointerSize(), "byref.isa");
2694
2695 // Store the address of the variable into its own forwarding pointer.
2696 storeHeaderField(addr.getPointer(), getPointerSize(), "byref.forwarding");
2697
2698 // Blocks ABI:
2699 // c) the flags field is set to either 0 if no helper functions are
2700 // needed or BLOCK_BYREF_HAS_COPY_DISPOSE if they are,
2701 BlockFlags flags;
2702 if (helpers) flags |= BLOCK_BYREF_HAS_COPY_DISPOSE;
2703 if (ByRefHasLifetime) {
2704 if (HasByrefExtendedLayout) flags |= BLOCK_BYREF_LAYOUT_EXTENDED;
2705 else switch (ByrefLifetime) {
2706 case Qualifiers::OCL_Strong:
2707 flags |= BLOCK_BYREF_LAYOUT_STRONG;
2708 break;
2709 case Qualifiers::OCL_Weak:
2710 flags |= BLOCK_BYREF_LAYOUT_WEAK;
2711 break;
2712 case Qualifiers::OCL_ExplicitNone:
2713 flags |= BLOCK_BYREF_LAYOUT_UNRETAINED;
2714 break;
2715 case Qualifiers::OCL_None:
2716 if (!type->isObjCObjectPointerType() && !type->isBlockPointerType())
2717 flags |= BLOCK_BYREF_LAYOUT_NON_OBJECT;
2718 break;
2719 default:
2720 break;
2721 }
2722 if (CGM.getLangOpts().ObjCGCBitmapPrint) {
2723 printf(format: "\n Inline flag for BYREF variable layout (%d):", flags.getBitMask());
2724 if (flags & BLOCK_BYREF_HAS_COPY_DISPOSE)
2725 printf(format: " BLOCK_BYREF_HAS_COPY_DISPOSE");
2726 if (flags & BLOCK_BYREF_LAYOUT_MASK) {
2727 BlockFlags ThisFlag(flags.getBitMask() & BLOCK_BYREF_LAYOUT_MASK);
2728 if (ThisFlag == BLOCK_BYREF_LAYOUT_EXTENDED)
2729 printf(format: " BLOCK_BYREF_LAYOUT_EXTENDED");
2730 if (ThisFlag == BLOCK_BYREF_LAYOUT_STRONG)
2731 printf(format: " BLOCK_BYREF_LAYOUT_STRONG");
2732 if (ThisFlag == BLOCK_BYREF_LAYOUT_WEAK)
2733 printf(format: " BLOCK_BYREF_LAYOUT_WEAK");
2734 if (ThisFlag == BLOCK_BYREF_LAYOUT_UNRETAINED)
2735 printf(format: " BLOCK_BYREF_LAYOUT_UNRETAINED");
2736 if (ThisFlag == BLOCK_BYREF_LAYOUT_NON_OBJECT)
2737 printf(format: " BLOCK_BYREF_LAYOUT_NON_OBJECT");
2738 }
2739 printf(format: "\n");
2740 }
2741 }
2742 storeHeaderField(llvm::ConstantInt::get(Ty: IntTy, V: flags.getBitMask()),
2743 getIntSize(), "byref.flags");
2744
2745 CharUnits byrefSize = CGM.GetTargetTypeStoreSize(Ty: byrefType);
2746 V = llvm::ConstantInt::get(Ty: IntTy, V: byrefSize.getQuantity());
2747 storeHeaderField(V, getIntSize(), "byref.size");
2748
2749 if (helpers) {
2750 storeHeaderField(helpers->CopyHelper, getPointerSize(),
2751 "byref.copyHelper");
2752 storeHeaderField(helpers->DisposeHelper, getPointerSize(),
2753 "byref.disposeHelper");
2754 }
2755
2756 if (ByRefHasLifetime && HasByrefExtendedLayout) {
2757 auto layoutInfo = CGM.getObjCRuntime().BuildByrefLayout(CGM, T: type);
2758 storeHeaderField(layoutInfo, getPointerSize(), "byref.layout");
2759 }
2760}
2761
2762void CodeGenFunction::BuildBlockRelease(llvm::Value *V, BlockFieldFlags flags,
2763 bool CanThrow) {
2764 llvm::FunctionCallee F = CGM.getBlockObjectDispose();
2765 llvm::Value *args[] = {V,
2766 llvm::ConstantInt::get(Ty: Int32Ty, V: flags.getBitMask())};
2767
2768 if (CanThrow)
2769 EmitRuntimeCallOrInvoke(callee: F, args);
2770 else
2771 EmitNounwindRuntimeCall(callee: F, args);
2772}
2773
2774void CodeGenFunction::enterByrefCleanup(CleanupKind Kind, Address Addr,
2775 BlockFieldFlags Flags,
2776 bool LoadBlockVarAddr, bool CanThrow) {
2777 EHStack.pushCleanup<CallBlockRelease>(Kind, A: Addr, A: Flags, A: LoadBlockVarAddr,
2778 A: CanThrow);
2779}
2780
2781/// Adjust the declaration of something from the blocks API.
2782static void configureBlocksRuntimeObject(CodeGenModule &CGM,
2783 llvm::Constant *C) {
2784 auto *GV = cast<llvm::GlobalValue>(Val: C->stripPointerCasts());
2785
2786 if (CGM.getTarget().getTriple().isOSBinFormatCOFF()) {
2787 IdentifierInfo &II = CGM.getContext().Idents.get(Name: C->getName());
2788 TranslationUnitDecl *TUDecl = CGM.getContext().getTranslationUnitDecl();
2789 DeclContext *DC = TranslationUnitDecl::castToDeclContext(D: TUDecl);
2790
2791 assert((isa<llvm::Function>(C->stripPointerCasts()) ||
2792 isa<llvm::GlobalVariable>(C->stripPointerCasts())) &&
2793 "expected Function or GlobalVariable");
2794
2795 const NamedDecl *ND = nullptr;
2796 for (const auto *Result : DC->lookup(Name: &II))
2797 if ((ND = dyn_cast<FunctionDecl>(Val: Result)) ||
2798 (ND = dyn_cast<VarDecl>(Val: Result)))
2799 break;
2800
2801 // TODO: support static blocks runtime
2802 if (GV->isDeclaration() && (!ND || !ND->hasAttr<DLLExportAttr>())) {
2803 GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
2804 GV->setLinkage(llvm::GlobalValue::ExternalLinkage);
2805 } else {
2806 GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
2807 GV->setLinkage(llvm::GlobalValue::ExternalLinkage);
2808 }
2809 }
2810
2811 if (CGM.getLangOpts().BlocksRuntimeOptional && GV->isDeclaration() &&
2812 GV->hasExternalLinkage())
2813 GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
2814
2815 CGM.setDSOLocal(GV);
2816}
2817
2818llvm::FunctionCallee CodeGenModule::getBlockObjectDispose() {
2819 if (BlockObjectDispose)
2820 return BlockObjectDispose;
2821
2822 llvm::Type *args[] = { Int8PtrTy, Int32Ty };
2823 llvm::FunctionType *fty
2824 = llvm::FunctionType::get(Result: VoidTy, Params: args, isVarArg: false);
2825 BlockObjectDispose = CreateRuntimeFunction(Ty: fty, Name: "_Block_object_dispose");
2826 configureBlocksRuntimeObject(
2827 CGM&: *this, C: cast<llvm::Constant>(Val: BlockObjectDispose.getCallee()));
2828 return BlockObjectDispose;
2829}
2830
2831llvm::FunctionCallee CodeGenModule::getBlockObjectAssign() {
2832 if (BlockObjectAssign)
2833 return BlockObjectAssign;
2834
2835 llvm::Type *args[] = { Int8PtrTy, Int8PtrTy, Int32Ty };
2836 llvm::FunctionType *fty
2837 = llvm::FunctionType::get(Result: VoidTy, Params: args, isVarArg: false);
2838 BlockObjectAssign = CreateRuntimeFunction(Ty: fty, Name: "_Block_object_assign");
2839 configureBlocksRuntimeObject(
2840 CGM&: *this, C: cast<llvm::Constant>(Val: BlockObjectAssign.getCallee()));
2841 return BlockObjectAssign;
2842}
2843
2844llvm::Constant *CodeGenModule::getNSConcreteGlobalBlock() {
2845 if (NSConcreteGlobalBlock)
2846 return NSConcreteGlobalBlock;
2847
2848 NSConcreteGlobalBlock = GetOrCreateLLVMGlobal(
2849 MangledName: "_NSConcreteGlobalBlock", Ty: Int8PtrTy, AddrSpace: LangAS::Default, D: nullptr);
2850 configureBlocksRuntimeObject(CGM&: *this, C: NSConcreteGlobalBlock);
2851 return NSConcreteGlobalBlock;
2852}
2853
2854llvm::Constant *CodeGenModule::getNSConcreteStackBlock() {
2855 if (NSConcreteStackBlock)
2856 return NSConcreteStackBlock;
2857
2858 NSConcreteStackBlock = GetOrCreateLLVMGlobal(
2859 MangledName: "_NSConcreteStackBlock", Ty: Int8PtrTy, AddrSpace: LangAS::Default, D: nullptr);
2860 configureBlocksRuntimeObject(CGM&: *this, C: NSConcreteStackBlock);
2861 return NSConcreteStackBlock;
2862}
2863

source code of clang/lib/CodeGen/CGBlocks.cpp