1 //===--- CGDecl.cpp - Emit LLVM Code for declarations ---------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This contains code to emit Decl nodes as LLVM code.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "CodeGenFunction.h"
15 #include "CGBlocks.h"
16 #include "CGCleanup.h"
17 #include "CGDebugInfo.h"
18 #include "CGOpenCLRuntime.h"
19 #include "CodeGenModule.h"
20 #include "clang/AST/ASTContext.h"
21 #include "clang/AST/CharUnits.h"
22 #include "clang/AST/Decl.h"
23 #include "clang/AST/DeclObjC.h"
24 #include "clang/Basic/SourceManager.h"
25 #include "clang/Basic/TargetInfo.h"
26 #include "clang/CodeGen/CGFunctionInfo.h"
27 #include "clang/Frontend/CodeGenOptions.h"
28 #include "llvm/IR/DataLayout.h"
29 #include "llvm/IR/GlobalVariable.h"
30 #include "llvm/IR/Intrinsics.h"
31 #include "llvm/IR/Type.h"
32 using namespace clang;
33 using namespace CodeGen;
34
35
EmitDecl(const Decl & D)36 void CodeGenFunction::EmitDecl(const Decl &D) {
37 switch (D.getKind()) {
38 case Decl::BuiltinTemplate:
39 case Decl::TranslationUnit:
40 case Decl::ExternCContext:
41 case Decl::Namespace:
42 case Decl::UnresolvedUsingTypename:
43 case Decl::ClassTemplateSpecialization:
44 case Decl::ClassTemplatePartialSpecialization:
45 case Decl::VarTemplateSpecialization:
46 case Decl::VarTemplatePartialSpecialization:
47 case Decl::TemplateTypeParm:
48 case Decl::UnresolvedUsingValue:
49 case Decl::NonTypeTemplateParm:
50 case Decl::CXXMethod:
51 case Decl::CXXConstructor:
52 case Decl::CXXDestructor:
53 case Decl::CXXConversion:
54 case Decl::Field:
55 case Decl::MSProperty:
56 case Decl::IndirectField:
57 case Decl::ObjCIvar:
58 case Decl::ObjCAtDefsField:
59 case Decl::ParmVar:
60 case Decl::ImplicitParam:
61 case Decl::ClassTemplate:
62 case Decl::VarTemplate:
63 case Decl::FunctionTemplate:
64 case Decl::TypeAliasTemplate:
65 case Decl::TemplateTemplateParm:
66 case Decl::ObjCMethod:
67 case Decl::ObjCCategory:
68 case Decl::ObjCProtocol:
69 case Decl::ObjCInterface:
70 case Decl::ObjCCategoryImpl:
71 case Decl::ObjCImplementation:
72 case Decl::ObjCProperty:
73 case Decl::ObjCCompatibleAlias:
74 case Decl::AccessSpec:
75 case Decl::LinkageSpec:
76 case Decl::ObjCPropertyImpl:
77 case Decl::FileScopeAsm:
78 case Decl::Friend:
79 case Decl::FriendTemplate:
80 case Decl::Block:
81 case Decl::Captured:
82 case Decl::ClassScopeFunctionSpecialization:
83 case Decl::UsingShadow:
84 case Decl::ObjCTypeParam:
85 llvm_unreachable("Declaration should not be in declstmts!");
86 case Decl::Function: // void X();
87 case Decl::Record: // struct/union/class X;
88 case Decl::Enum: // enum X;
89 case Decl::EnumConstant: // enum ? { X = ? }
90 case Decl::CXXRecord: // struct/union/class X; [C++]
91 case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
92 case Decl::Label: // __label__ x;
93 case Decl::Import:
94 case Decl::OMPThreadPrivate:
95 case Decl::Empty:
96 // None of these decls require codegen support.
97 return;
98
99 case Decl::NamespaceAlias:
100 if (CGDebugInfo *DI = getDebugInfo())
101 DI->EmitNamespaceAlias(cast<NamespaceAliasDecl>(D));
102 return;
103 case Decl::Using: // using X; [C++]
104 if (CGDebugInfo *DI = getDebugInfo())
105 DI->EmitUsingDecl(cast<UsingDecl>(D));
106 return;
107 case Decl::UsingDirective: // using namespace X; [C++]
108 if (CGDebugInfo *DI = getDebugInfo())
109 DI->EmitUsingDirective(cast<UsingDirectiveDecl>(D));
110 return;
111 case Decl::Var: {
112 const VarDecl &VD = cast<VarDecl>(D);
113 assert(VD.isLocalVarDecl() &&
114 "Should not see file-scope variables inside a function!");
115 return EmitVarDecl(VD);
116 }
117
118 case Decl::Typedef: // typedef int X;
119 case Decl::TypeAlias: { // using X = int; [C++0x]
120 const TypedefNameDecl &TD = cast<TypedefNameDecl>(D);
121 QualType Ty = TD.getUnderlyingType();
122
123 if (Ty->isVariablyModifiedType())
124 EmitVariablyModifiedType(Ty);
125 }
126 }
127 }
128
129 /// EmitVarDecl - This method handles emission of any variable declaration
130 /// inside a function, including static vars etc.
EmitVarDecl(const VarDecl & D)131 void CodeGenFunction::EmitVarDecl(const VarDecl &D) {
132 if (D.isStaticLocal()) {
133 llvm::GlobalValue::LinkageTypes Linkage =
134 CGM.getLLVMLinkageVarDefinition(&D, /*isConstant=*/false);
135
136 // FIXME: We need to force the emission/use of a guard variable for
137 // some variables even if we can constant-evaluate them because
138 // we can't guarantee every translation unit will constant-evaluate them.
139
140 return EmitStaticVarDecl(D, Linkage);
141 }
142
143 if (D.hasExternalStorage())
144 // Don't emit it now, allow it to be emitted lazily on its first use.
145 return;
146
147 if (D.getType().getAddressSpace() == LangAS::opencl_local)
148 return CGM.getOpenCLRuntime().EmitWorkGroupLocalVarDecl(*this, D);
149
150 assert(D.hasLocalStorage());
151 return EmitAutoVarDecl(D);
152 }
153
getStaticDeclName(CodeGenModule & CGM,const VarDecl & D)154 static std::string getStaticDeclName(CodeGenModule &CGM, const VarDecl &D) {
155 if (CGM.getLangOpts().CPlusPlus)
156 return CGM.getMangledName(&D).str();
157
158 // If this isn't C++, we don't need a mangled name, just a pretty one.
159 assert(!D.isExternallyVisible() && "name shouldn't matter");
160 std::string ContextName;
161 const DeclContext *DC = D.getDeclContext();
162 if (auto *CD = dyn_cast<CapturedDecl>(DC))
163 DC = cast<DeclContext>(CD->getNonClosureContext());
164 if (const auto *FD = dyn_cast<FunctionDecl>(DC))
165 ContextName = CGM.getMangledName(FD);
166 else if (const auto *BD = dyn_cast<BlockDecl>(DC))
167 ContextName = CGM.getBlockMangledName(GlobalDecl(), BD);
168 else if (const auto *OMD = dyn_cast<ObjCMethodDecl>(DC))
169 ContextName = OMD->getSelector().getAsString();
170 else
171 llvm_unreachable("Unknown context for static var decl");
172
173 ContextName += "." + D.getNameAsString();
174 return ContextName;
175 }
176
getOrCreateStaticVarDecl(const VarDecl & D,llvm::GlobalValue::LinkageTypes Linkage)177 llvm::Constant *CodeGenModule::getOrCreateStaticVarDecl(
178 const VarDecl &D, llvm::GlobalValue::LinkageTypes Linkage) {
179 // In general, we don't always emit static var decls once before we reference
180 // them. It is possible to reference them before emitting the function that
181 // contains them, and it is possible to emit the containing function multiple
182 // times.
183 if (llvm::Constant *ExistingGV = StaticLocalDeclMap[&D])
184 return ExistingGV;
185
186 QualType Ty = D.getType();
187 assert(Ty->isConstantSizeType() && "VLAs can't be static");
188
189 // Use the label if the variable is renamed with the asm-label extension.
190 std::string Name;
191 if (D.hasAttr<AsmLabelAttr>())
192 Name = getMangledName(&D);
193 else
194 Name = getStaticDeclName(*this, D);
195
196 llvm::Type *LTy = getTypes().ConvertTypeForMem(Ty);
197 unsigned AddrSpace =
198 GetGlobalVarAddressSpace(&D, getContext().getTargetAddressSpace(Ty));
199
200 // Local address space cannot have an initializer.
201 llvm::Constant *Init = nullptr;
202 if (Ty.getAddressSpace() != LangAS::opencl_local)
203 Init = EmitNullConstant(Ty);
204 else
205 Init = llvm::UndefValue::get(LTy);
206
207 llvm::GlobalVariable *GV =
208 new llvm::GlobalVariable(getModule(), LTy,
209 Ty.isConstant(getContext()), Linkage,
210 Init, Name, nullptr,
211 llvm::GlobalVariable::NotThreadLocal,
212 AddrSpace);
213 GV->setAlignment(getContext().getDeclAlign(&D).getQuantity());
214 setGlobalVisibility(GV, &D);
215
216 if (supportsCOMDAT() && GV->isWeakForLinker())
217 GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
218
219 if (D.getTLSKind())
220 setTLSMode(GV, D);
221
222 if (D.isExternallyVisible()) {
223 if (D.hasAttr<DLLImportAttr>())
224 GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass);
225 else if (D.hasAttr<DLLExportAttr>())
226 GV->setDLLStorageClass(llvm::GlobalVariable::DLLExportStorageClass);
227 }
228
229 // Make sure the result is of the correct type.
230 unsigned ExpectedAddrSpace = getContext().getTargetAddressSpace(Ty);
231 llvm::Constant *Addr = GV;
232 if (AddrSpace != ExpectedAddrSpace) {
233 llvm::PointerType *PTy = llvm::PointerType::get(LTy, ExpectedAddrSpace);
234 Addr = llvm::ConstantExpr::getAddrSpaceCast(GV, PTy);
235 }
236
237 setStaticLocalDeclAddress(&D, Addr);
238
239 // Ensure that the static local gets initialized by making sure the parent
240 // function gets emitted eventually.
241 const Decl *DC = cast<Decl>(D.getDeclContext());
242
243 // We can't name blocks or captured statements directly, so try to emit their
244 // parents.
245 if (isa<BlockDecl>(DC) || isa<CapturedDecl>(DC)) {
246 DC = DC->getNonClosureContext();
247 // FIXME: Ensure that global blocks get emitted.
248 if (!DC)
249 return Addr;
250 }
251
252 GlobalDecl GD;
253 if (const auto *CD = dyn_cast<CXXConstructorDecl>(DC))
254 GD = GlobalDecl(CD, Ctor_Base);
255 else if (const auto *DD = dyn_cast<CXXDestructorDecl>(DC))
256 GD = GlobalDecl(DD, Dtor_Base);
257 else if (const auto *FD = dyn_cast<FunctionDecl>(DC))
258 GD = GlobalDecl(FD);
259 else {
260 // Don't do anything for Obj-C method decls or global closures. We should
261 // never defer them.
262 assert(isa<ObjCMethodDecl>(DC) && "unexpected parent code decl");
263 }
264 if (GD.getDecl())
265 (void)GetAddrOfGlobal(GD);
266
267 return Addr;
268 }
269
270 /// hasNontrivialDestruction - Determine whether a type's destruction is
271 /// non-trivial. If so, and the variable uses static initialization, we must
272 /// register its destructor to run on exit.
hasNontrivialDestruction(QualType T)273 static bool hasNontrivialDestruction(QualType T) {
274 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
275 return RD && !RD->hasTrivialDestructor();
276 }
277
278 /// AddInitializerToStaticVarDecl - Add the initializer for 'D' to the
279 /// global variable that has already been created for it. If the initializer
280 /// has a different type than GV does, this may free GV and return a different
281 /// one. Otherwise it just returns GV.
282 llvm::GlobalVariable *
AddInitializerToStaticVarDecl(const VarDecl & D,llvm::GlobalVariable * GV)283 CodeGenFunction::AddInitializerToStaticVarDecl(const VarDecl &D,
284 llvm::GlobalVariable *GV) {
285 llvm::Constant *Init = CGM.EmitConstantInit(D, this);
286
287 // If constant emission failed, then this should be a C++ static
288 // initializer.
289 if (!Init) {
290 if (!getLangOpts().CPlusPlus)
291 CGM.ErrorUnsupported(D.getInit(), "constant l-value expression");
292 else if (Builder.GetInsertBlock()) {
293 // Since we have a static initializer, this global variable can't
294 // be constant.
295 GV->setConstant(false);
296
297 EmitCXXGuardedInit(D, GV, /*PerformInit*/true);
298 }
299 return GV;
300 }
301
302 // The initializer may differ in type from the global. Rewrite
303 // the global to match the initializer. (We have to do this
304 // because some types, like unions, can't be completely represented
305 // in the LLVM type system.)
306 if (GV->getType()->getElementType() != Init->getType()) {
307 llvm::GlobalVariable *OldGV = GV;
308
309 GV = new llvm::GlobalVariable(CGM.getModule(), Init->getType(),
310 OldGV->isConstant(),
311 OldGV->getLinkage(), Init, "",
312 /*InsertBefore*/ OldGV,
313 OldGV->getThreadLocalMode(),
314 CGM.getContext().getTargetAddressSpace(D.getType()));
315 GV->setVisibility(OldGV->getVisibility());
316 GV->setComdat(OldGV->getComdat());
317
318 // Steal the name of the old global
319 GV->takeName(OldGV);
320
321 // Replace all uses of the old global with the new global
322 llvm::Constant *NewPtrForOldDecl =
323 llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
324 OldGV->replaceAllUsesWith(NewPtrForOldDecl);
325
326 // Erase the old global, since it is no longer used.
327 OldGV->eraseFromParent();
328 }
329
330 GV->setConstant(CGM.isTypeConstant(D.getType(), true));
331 GV->setInitializer(Init);
332
333 if (hasNontrivialDestruction(D.getType())) {
334 // We have a constant initializer, but a nontrivial destructor. We still
335 // need to perform a guarded "initialization" in order to register the
336 // destructor.
337 EmitCXXGuardedInit(D, GV, /*PerformInit*/false);
338 }
339
340 return GV;
341 }
342
EmitStaticVarDecl(const VarDecl & D,llvm::GlobalValue::LinkageTypes Linkage)343 void CodeGenFunction::EmitStaticVarDecl(const VarDecl &D,
344 llvm::GlobalValue::LinkageTypes Linkage) {
345 // Check to see if we already have a global variable for this
346 // declaration. This can happen when double-emitting function
347 // bodies, e.g. with complete and base constructors.
348 llvm::Constant *addr = CGM.getOrCreateStaticVarDecl(D, Linkage);
349 CharUnits alignment = getContext().getDeclAlign(&D);
350
351 // Store into LocalDeclMap before generating initializer to handle
352 // circular references.
353 setAddrOfLocalVar(&D, Address(addr, alignment));
354
355 // We can't have a VLA here, but we can have a pointer to a VLA,
356 // even though that doesn't really make any sense.
357 // Make sure to evaluate VLA bounds now so that we have them for later.
358 if (D.getType()->isVariablyModifiedType())
359 EmitVariablyModifiedType(D.getType());
360
361 // Save the type in case adding the initializer forces a type change.
362 llvm::Type *expectedType = addr->getType();
363
364 llvm::GlobalVariable *var =
365 cast<llvm::GlobalVariable>(addr->stripPointerCasts());
366 // If this value has an initializer, emit it.
367 if (D.getInit())
368 var = AddInitializerToStaticVarDecl(D, var);
369
370 var->setAlignment(alignment.getQuantity());
371
372 if (D.hasAttr<AnnotateAttr>())
373 CGM.AddGlobalAnnotations(&D, var);
374
375 if (const SectionAttr *SA = D.getAttr<SectionAttr>())
376 var->setSection(SA->getName());
377
378 if (D.hasAttr<UsedAttr>())
379 CGM.addUsedGlobal(var);
380
381 // We may have to cast the constant because of the initializer
382 // mismatch above.
383 //
384 // FIXME: It is really dangerous to store this in the map; if anyone
385 // RAUW's the GV uses of this constant will be invalid.
386 llvm::Constant *castedAddr =
387 llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(var, expectedType);
388 if (var != castedAddr)
389 LocalDeclMap.find(&D)->second = Address(castedAddr, alignment);
390 CGM.setStaticLocalDeclAddress(&D, castedAddr);
391
392 CGM.getSanitizerMetadata()->reportGlobalToASan(var, D);
393
394 // Emit global variable debug descriptor for static vars.
395 CGDebugInfo *DI = getDebugInfo();
396 if (DI &&
397 CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo) {
398 DI->setLocation(D.getLocation());
399 DI->EmitGlobalVariable(var, &D);
400 }
401 }
402
403 namespace {
404 struct DestroyObject final : EHScopeStack::Cleanup {
DestroyObject__anon8923ffa70111::DestroyObject405 DestroyObject(Address addr, QualType type,
406 CodeGenFunction::Destroyer *destroyer,
407 bool useEHCleanupForArray)
408 : addr(addr), type(type), destroyer(destroyer),
409 useEHCleanupForArray(useEHCleanupForArray) {}
410
411 Address addr;
412 QualType type;
413 CodeGenFunction::Destroyer *destroyer;
414 bool useEHCleanupForArray;
415
Emit__anon8923ffa70111::DestroyObject416 void Emit(CodeGenFunction &CGF, Flags flags) override {
417 // Don't use an EH cleanup recursively from an EH cleanup.
418 bool useEHCleanupForArray =
419 flags.isForNormalCleanup() && this->useEHCleanupForArray;
420
421 CGF.emitDestroy(addr, type, destroyer, useEHCleanupForArray);
422 }
423 };
424
425 struct DestroyNRVOVariable final : EHScopeStack::Cleanup {
DestroyNRVOVariable__anon8923ffa70111::DestroyNRVOVariable426 DestroyNRVOVariable(Address addr,
427 const CXXDestructorDecl *Dtor,
428 llvm::Value *NRVOFlag)
429 : Dtor(Dtor), NRVOFlag(NRVOFlag), Loc(addr) {}
430
431 const CXXDestructorDecl *Dtor;
432 llvm::Value *NRVOFlag;
433 Address Loc;
434
Emit__anon8923ffa70111::DestroyNRVOVariable435 void Emit(CodeGenFunction &CGF, Flags flags) override {
436 // Along the exceptions path we always execute the dtor.
437 bool NRVO = flags.isForNormalCleanup() && NRVOFlag;
438
439 llvm::BasicBlock *SkipDtorBB = nullptr;
440 if (NRVO) {
441 // If we exited via NRVO, we skip the destructor call.
442 llvm::BasicBlock *RunDtorBB = CGF.createBasicBlock("nrvo.unused");
443 SkipDtorBB = CGF.createBasicBlock("nrvo.skipdtor");
444 llvm::Value *DidNRVO =
445 CGF.Builder.CreateFlagLoad(NRVOFlag, "nrvo.val");
446 CGF.Builder.CreateCondBr(DidNRVO, SkipDtorBB, RunDtorBB);
447 CGF.EmitBlock(RunDtorBB);
448 }
449
450 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
451 /*ForVirtualBase=*/false,
452 /*Delegating=*/false,
453 Loc);
454
455 if (NRVO) CGF.EmitBlock(SkipDtorBB);
456 }
457 };
458
459 struct CallStackRestore final : EHScopeStack::Cleanup {
460 Address Stack;
CallStackRestore__anon8923ffa70111::CallStackRestore461 CallStackRestore(Address Stack) : Stack(Stack) {}
Emit__anon8923ffa70111::CallStackRestore462 void Emit(CodeGenFunction &CGF, Flags flags) override {
463 llvm::Value *V = CGF.Builder.CreateLoad(Stack);
464 llvm::Value *F = CGF.CGM.getIntrinsic(llvm::Intrinsic::stackrestore);
465 CGF.Builder.CreateCall(F, V);
466 }
467 };
468
469 struct ExtendGCLifetime final : EHScopeStack::Cleanup {
470 const VarDecl &Var;
ExtendGCLifetime__anon8923ffa70111::ExtendGCLifetime471 ExtendGCLifetime(const VarDecl *var) : Var(*var) {}
472
Emit__anon8923ffa70111::ExtendGCLifetime473 void Emit(CodeGenFunction &CGF, Flags flags) override {
474 // Compute the address of the local variable, in case it's a
475 // byref or something.
476 DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false,
477 Var.getType(), VK_LValue, SourceLocation());
478 llvm::Value *value = CGF.EmitLoadOfScalar(CGF.EmitDeclRefLValue(&DRE),
479 SourceLocation());
480 CGF.EmitExtendGCLifetime(value);
481 }
482 };
483
484 struct CallCleanupFunction final : EHScopeStack::Cleanup {
485 llvm::Constant *CleanupFn;
486 const CGFunctionInfo &FnInfo;
487 const VarDecl &Var;
488
CallCleanupFunction__anon8923ffa70111::CallCleanupFunction489 CallCleanupFunction(llvm::Constant *CleanupFn, const CGFunctionInfo *Info,
490 const VarDecl *Var)
491 : CleanupFn(CleanupFn), FnInfo(*Info), Var(*Var) {}
492
Emit__anon8923ffa70111::CallCleanupFunction493 void Emit(CodeGenFunction &CGF, Flags flags) override {
494 DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false,
495 Var.getType(), VK_LValue, SourceLocation());
496 // Compute the address of the local variable, in case it's a byref
497 // or something.
498 llvm::Value *Addr = CGF.EmitDeclRefLValue(&DRE).getPointer();
499
500 // In some cases, the type of the function argument will be different from
501 // the type of the pointer. An example of this is
502 // void f(void* arg);
503 // __attribute__((cleanup(f))) void *g;
504 //
505 // To fix this we insert a bitcast here.
506 QualType ArgTy = FnInfo.arg_begin()->type;
507 llvm::Value *Arg =
508 CGF.Builder.CreateBitCast(Addr, CGF.ConvertType(ArgTy));
509
510 CallArgList Args;
511 Args.add(RValue::get(Arg),
512 CGF.getContext().getPointerType(Var.getType()));
513 CGF.EmitCall(FnInfo, CleanupFn, ReturnValueSlot(), Args);
514 }
515 };
516
517 /// A cleanup to call @llvm.lifetime.end.
518 class CallLifetimeEnd final : public EHScopeStack::Cleanup {
519 llvm::Value *Addr;
520 llvm::Value *Size;
521 public:
CallLifetimeEnd(Address addr,llvm::Value * size)522 CallLifetimeEnd(Address addr, llvm::Value *size)
523 : Addr(addr.getPointer()), Size(size) {}
524
Emit(CodeGenFunction & CGF,Flags flags)525 void Emit(CodeGenFunction &CGF, Flags flags) override {
526 CGF.EmitLifetimeEnd(Size, Addr);
527 }
528 };
529 }
530
531 /// EmitAutoVarWithLifetime - Does the setup required for an automatic
532 /// variable with lifetime.
EmitAutoVarWithLifetime(CodeGenFunction & CGF,const VarDecl & var,Address addr,Qualifiers::ObjCLifetime lifetime)533 static void EmitAutoVarWithLifetime(CodeGenFunction &CGF, const VarDecl &var,
534 Address addr,
535 Qualifiers::ObjCLifetime lifetime) {
536 switch (lifetime) {
537 case Qualifiers::OCL_None:
538 llvm_unreachable("present but none");
539
540 case Qualifiers::OCL_ExplicitNone:
541 // nothing to do
542 break;
543
544 case Qualifiers::OCL_Strong: {
545 CodeGenFunction::Destroyer *destroyer =
546 (var.hasAttr<ObjCPreciseLifetimeAttr>()
547 ? CodeGenFunction::destroyARCStrongPrecise
548 : CodeGenFunction::destroyARCStrongImprecise);
549
550 CleanupKind cleanupKind = CGF.getARCCleanupKind();
551 CGF.pushDestroy(cleanupKind, addr, var.getType(), destroyer,
552 cleanupKind & EHCleanup);
553 break;
554 }
555 case Qualifiers::OCL_Autoreleasing:
556 // nothing to do
557 break;
558
559 case Qualifiers::OCL_Weak:
560 // __weak objects always get EH cleanups; otherwise, exceptions
561 // could cause really nasty crashes instead of mere leaks.
562 CGF.pushDestroy(NormalAndEHCleanup, addr, var.getType(),
563 CodeGenFunction::destroyARCWeak,
564 /*useEHCleanup*/ true);
565 break;
566 }
567 }
568
isAccessedBy(const VarDecl & var,const Stmt * s)569 static bool isAccessedBy(const VarDecl &var, const Stmt *s) {
570 if (const Expr *e = dyn_cast<Expr>(s)) {
571 // Skip the most common kinds of expressions that make
572 // hierarchy-walking expensive.
573 s = e = e->IgnoreParenCasts();
574
575 if (const DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e))
576 return (ref->getDecl() == &var);
577 if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) {
578 const BlockDecl *block = be->getBlockDecl();
579 for (const auto &I : block->captures()) {
580 if (I.getVariable() == &var)
581 return true;
582 }
583 }
584 }
585
586 for (const Stmt *SubStmt : s->children())
587 // SubStmt might be null; as in missing decl or conditional of an if-stmt.
588 if (SubStmt && isAccessedBy(var, SubStmt))
589 return true;
590
591 return false;
592 }
593
isAccessedBy(const ValueDecl * decl,const Expr * e)594 static bool isAccessedBy(const ValueDecl *decl, const Expr *e) {
595 if (!decl) return false;
596 if (!isa<VarDecl>(decl)) return false;
597 const VarDecl *var = cast<VarDecl>(decl);
598 return isAccessedBy(*var, e);
599 }
600
tryEmitARCCopyWeakInit(CodeGenFunction & CGF,const LValue & destLV,const Expr * init)601 static bool tryEmitARCCopyWeakInit(CodeGenFunction &CGF,
602 const LValue &destLV, const Expr *init) {
603 bool needsCast = false;
604
605 while (auto castExpr = dyn_cast<CastExpr>(init->IgnoreParens())) {
606 switch (castExpr->getCastKind()) {
607 // Look through casts that don't require representation changes.
608 case CK_NoOp:
609 case CK_BitCast:
610 case CK_BlockPointerToObjCPointerCast:
611 needsCast = true;
612 break;
613
614 // If we find an l-value to r-value cast from a __weak variable,
615 // emit this operation as a copy or move.
616 case CK_LValueToRValue: {
617 const Expr *srcExpr = castExpr->getSubExpr();
618 if (srcExpr->getType().getObjCLifetime() != Qualifiers::OCL_Weak)
619 return false;
620
621 // Emit the source l-value.
622 LValue srcLV = CGF.EmitLValue(srcExpr);
623
624 // Handle a formal type change to avoid asserting.
625 auto srcAddr = srcLV.getAddress();
626 if (needsCast) {
627 srcAddr = CGF.Builder.CreateElementBitCast(srcAddr,
628 destLV.getAddress().getElementType());
629 }
630
631 // If it was an l-value, use objc_copyWeak.
632 if (srcExpr->getValueKind() == VK_LValue) {
633 CGF.EmitARCCopyWeak(destLV.getAddress(), srcAddr);
634 } else {
635 assert(srcExpr->getValueKind() == VK_XValue);
636 CGF.EmitARCMoveWeak(destLV.getAddress(), srcAddr);
637 }
638 return true;
639 }
640
641 // Stop at anything else.
642 default:
643 return false;
644 }
645
646 init = castExpr->getSubExpr();
647 continue;
648 }
649 return false;
650 }
651
drillIntoBlockVariable(CodeGenFunction & CGF,LValue & lvalue,const VarDecl * var)652 static void drillIntoBlockVariable(CodeGenFunction &CGF,
653 LValue &lvalue,
654 const VarDecl *var) {
655 lvalue.setAddress(CGF.emitBlockByrefAddress(lvalue.getAddress(), var));
656 }
657
EmitScalarInit(const Expr * init,const ValueDecl * D,LValue lvalue,bool capturedByInit)658 void CodeGenFunction::EmitScalarInit(const Expr *init, const ValueDecl *D,
659 LValue lvalue, bool capturedByInit) {
660 Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime();
661 if (!lifetime) {
662 llvm::Value *value = EmitScalarExpr(init);
663 if (capturedByInit)
664 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
665 EmitStoreThroughLValue(RValue::get(value), lvalue, true);
666 return;
667 }
668
669 if (const CXXDefaultInitExpr *DIE = dyn_cast<CXXDefaultInitExpr>(init))
670 init = DIE->getExpr();
671
672 // If we're emitting a value with lifetime, we have to do the
673 // initialization *before* we leave the cleanup scopes.
674 if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(init)) {
675 enterFullExpression(ewc);
676 init = ewc->getSubExpr();
677 }
678 CodeGenFunction::RunCleanupsScope Scope(*this);
679
680 // We have to maintain the illusion that the variable is
681 // zero-initialized. If the variable might be accessed in its
682 // initializer, zero-initialize before running the initializer, then
683 // actually perform the initialization with an assign.
684 bool accessedByInit = false;
685 if (lifetime != Qualifiers::OCL_ExplicitNone)
686 accessedByInit = (capturedByInit || isAccessedBy(D, init));
687 if (accessedByInit) {
688 LValue tempLV = lvalue;
689 // Drill down to the __block object if necessary.
690 if (capturedByInit) {
691 // We can use a simple GEP for this because it can't have been
692 // moved yet.
693 tempLV.setAddress(emitBlockByrefAddress(tempLV.getAddress(),
694 cast<VarDecl>(D),
695 /*follow*/ false));
696 }
697
698 auto ty = cast<llvm::PointerType>(tempLV.getAddress().getElementType());
699 llvm::Value *zero = llvm::ConstantPointerNull::get(ty);
700
701 // If __weak, we want to use a barrier under certain conditions.
702 if (lifetime == Qualifiers::OCL_Weak)
703 EmitARCInitWeak(tempLV.getAddress(), zero);
704
705 // Otherwise just do a simple store.
706 else
707 EmitStoreOfScalar(zero, tempLV, /* isInitialization */ true);
708 }
709
710 // Emit the initializer.
711 llvm::Value *value = nullptr;
712
713 switch (lifetime) {
714 case Qualifiers::OCL_None:
715 llvm_unreachable("present but none");
716
717 case Qualifiers::OCL_ExplicitNone:
718 // nothing to do
719 value = EmitScalarExpr(init);
720 break;
721
722 case Qualifiers::OCL_Strong: {
723 value = EmitARCRetainScalarExpr(init);
724 break;
725 }
726
727 case Qualifiers::OCL_Weak: {
728 // If it's not accessed by the initializer, try to emit the
729 // initialization with a copy or move.
730 if (!accessedByInit && tryEmitARCCopyWeakInit(*this, lvalue, init)) {
731 return;
732 }
733
734 // No way to optimize a producing initializer into this. It's not
735 // worth optimizing for, because the value will immediately
736 // disappear in the common case.
737 value = EmitScalarExpr(init);
738
739 if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
740 if (accessedByInit)
741 EmitARCStoreWeak(lvalue.getAddress(), value, /*ignored*/ true);
742 else
743 EmitARCInitWeak(lvalue.getAddress(), value);
744 return;
745 }
746
747 case Qualifiers::OCL_Autoreleasing:
748 value = EmitARCRetainAutoreleaseScalarExpr(init);
749 break;
750 }
751
752 if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
753
754 // If the variable might have been accessed by its initializer, we
755 // might have to initialize with a barrier. We have to do this for
756 // both __weak and __strong, but __weak got filtered out above.
757 if (accessedByInit && lifetime == Qualifiers::OCL_Strong) {
758 llvm::Value *oldValue = EmitLoadOfScalar(lvalue, init->getExprLoc());
759 EmitStoreOfScalar(value, lvalue, /* isInitialization */ true);
760 EmitARCRelease(oldValue, ARCImpreciseLifetime);
761 return;
762 }
763
764 EmitStoreOfScalar(value, lvalue, /* isInitialization */ true);
765 }
766
767 /// EmitScalarInit - Initialize the given lvalue with the given object.
EmitScalarInit(llvm::Value * init,LValue lvalue)768 void CodeGenFunction::EmitScalarInit(llvm::Value *init, LValue lvalue) {
769 Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime();
770 if (!lifetime)
771 return EmitStoreThroughLValue(RValue::get(init), lvalue, true);
772
773 switch (lifetime) {
774 case Qualifiers::OCL_None:
775 llvm_unreachable("present but none");
776
777 case Qualifiers::OCL_ExplicitNone:
778 // nothing to do
779 break;
780
781 case Qualifiers::OCL_Strong:
782 init = EmitARCRetain(lvalue.getType(), init);
783 break;
784
785 case Qualifiers::OCL_Weak:
786 // Initialize and then skip the primitive store.
787 EmitARCInitWeak(lvalue.getAddress(), init);
788 return;
789
790 case Qualifiers::OCL_Autoreleasing:
791 init = EmitARCRetainAutorelease(lvalue.getType(), init);
792 break;
793 }
794
795 EmitStoreOfScalar(init, lvalue, /* isInitialization */ true);
796 }
797
798 /// canEmitInitWithFewStoresAfterMemset - Decide whether we can emit the
799 /// non-zero parts of the specified initializer with equal or fewer than
800 /// NumStores scalar stores.
canEmitInitWithFewStoresAfterMemset(llvm::Constant * Init,unsigned & NumStores)801 static bool canEmitInitWithFewStoresAfterMemset(llvm::Constant *Init,
802 unsigned &NumStores) {
803 // Zero and Undef never requires any extra stores.
804 if (isa<llvm::ConstantAggregateZero>(Init) ||
805 isa<llvm::ConstantPointerNull>(Init) ||
806 isa<llvm::UndefValue>(Init))
807 return true;
808 if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) ||
809 isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
810 isa<llvm::ConstantExpr>(Init))
811 return Init->isNullValue() || NumStores--;
812
813 // See if we can emit each element.
814 if (isa<llvm::ConstantArray>(Init) || isa<llvm::ConstantStruct>(Init)) {
815 for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
816 llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
817 if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores))
818 return false;
819 }
820 return true;
821 }
822
823 if (llvm::ConstantDataSequential *CDS =
824 dyn_cast<llvm::ConstantDataSequential>(Init)) {
825 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
826 llvm::Constant *Elt = CDS->getElementAsConstant(i);
827 if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores))
828 return false;
829 }
830 return true;
831 }
832
833 // Anything else is hard and scary.
834 return false;
835 }
836
837 /// emitStoresForInitAfterMemset - For inits that
838 /// canEmitInitWithFewStoresAfterMemset returned true for, emit the scalar
839 /// stores that would be required.
emitStoresForInitAfterMemset(llvm::Constant * Init,llvm::Value * Loc,bool isVolatile,CGBuilderTy & Builder)840 static void emitStoresForInitAfterMemset(llvm::Constant *Init, llvm::Value *Loc,
841 bool isVolatile, CGBuilderTy &Builder) {
842 assert(!Init->isNullValue() && !isa<llvm::UndefValue>(Init) &&
843 "called emitStoresForInitAfterMemset for zero or undef value.");
844
845 if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) ||
846 isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
847 isa<llvm::ConstantExpr>(Init)) {
848 Builder.CreateDefaultAlignedStore(Init, Loc, isVolatile);
849 return;
850 }
851
852 if (llvm::ConstantDataSequential *CDS =
853 dyn_cast<llvm::ConstantDataSequential>(Init)) {
854 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
855 llvm::Constant *Elt = CDS->getElementAsConstant(i);
856
857 // If necessary, get a pointer to the element and emit it.
858 if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
859 emitStoresForInitAfterMemset(
860 Elt, Builder.CreateConstGEP2_32(Init->getType(), Loc, 0, i),
861 isVolatile, Builder);
862 }
863 return;
864 }
865
866 assert((isa<llvm::ConstantStruct>(Init) || isa<llvm::ConstantArray>(Init)) &&
867 "Unknown value type!");
868
869 for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
870 llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
871
872 // If necessary, get a pointer to the element and emit it.
873 if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
874 emitStoresForInitAfterMemset(
875 Elt, Builder.CreateConstGEP2_32(Init->getType(), Loc, 0, i),
876 isVolatile, Builder);
877 }
878 }
879
880
881 /// shouldUseMemSetPlusStoresToInitialize - Decide whether we should use memset
882 /// plus some stores to initialize a local variable instead of using a memcpy
883 /// from a constant global. It is beneficial to use memset if the global is all
884 /// zeros, or mostly zeros and large.
shouldUseMemSetPlusStoresToInitialize(llvm::Constant * Init,uint64_t GlobalSize)885 static bool shouldUseMemSetPlusStoresToInitialize(llvm::Constant *Init,
886 uint64_t GlobalSize) {
887 // If a global is all zeros, always use a memset.
888 if (isa<llvm::ConstantAggregateZero>(Init)) return true;
889
890 // If a non-zero global is <= 32 bytes, always use a memcpy. If it is large,
891 // do it if it will require 6 or fewer scalar stores.
892 // TODO: Should budget depends on the size? Avoiding a large global warrants
893 // plopping in more stores.
894 unsigned StoreBudget = 6;
895 uint64_t SizeLimit = 32;
896
897 return GlobalSize > SizeLimit &&
898 canEmitInitWithFewStoresAfterMemset(Init, StoreBudget);
899 }
900
901 /// EmitAutoVarDecl - Emit code and set up an entry in LocalDeclMap for a
902 /// variable declaration with auto, register, or no storage class specifier.
903 /// These turn into simple stack objects, or GlobalValues depending on target.
EmitAutoVarDecl(const VarDecl & D)904 void CodeGenFunction::EmitAutoVarDecl(const VarDecl &D) {
905 AutoVarEmission emission = EmitAutoVarAlloca(D);
906 EmitAutoVarInit(emission);
907 EmitAutoVarCleanups(emission);
908 }
909
910 /// Emit a lifetime.begin marker if some criteria are satisfied.
911 /// \return a pointer to the temporary size Value if a marker was emitted, null
912 /// otherwise
EmitLifetimeStart(uint64_t Size,llvm::Value * Addr)913 llvm::Value *CodeGenFunction::EmitLifetimeStart(uint64_t Size,
914 llvm::Value *Addr) {
915 // For now, only in optimized builds.
916 if (CGM.getCodeGenOpts().OptimizationLevel == 0)
917 return nullptr;
918
919 // Disable lifetime markers in msan builds.
920 // FIXME: Remove this when msan works with lifetime markers.
921 if (getLangOpts().Sanitize.has(SanitizerKind::Memory))
922 return nullptr;
923
924 llvm::Value *SizeV = llvm::ConstantInt::get(Int64Ty, Size);
925 Addr = Builder.CreateBitCast(Addr, Int8PtrTy);
926 llvm::CallInst *C =
927 Builder.CreateCall(CGM.getLLVMLifetimeStartFn(), {SizeV, Addr});
928 C->setDoesNotThrow();
929 return SizeV;
930 }
931
EmitLifetimeEnd(llvm::Value * Size,llvm::Value * Addr)932 void CodeGenFunction::EmitLifetimeEnd(llvm::Value *Size, llvm::Value *Addr) {
933 Addr = Builder.CreateBitCast(Addr, Int8PtrTy);
934 llvm::CallInst *C =
935 Builder.CreateCall(CGM.getLLVMLifetimeEndFn(), {Size, Addr});
936 C->setDoesNotThrow();
937 }
938
939 /// EmitAutoVarAlloca - Emit the alloca and debug information for a
940 /// local variable. Does not emit initialization or destruction.
941 CodeGenFunction::AutoVarEmission
EmitAutoVarAlloca(const VarDecl & D)942 CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) {
943 QualType Ty = D.getType();
944
945 AutoVarEmission emission(D);
946
947 bool isByRef = D.hasAttr<BlocksAttr>();
948 emission.IsByRef = isByRef;
949
950 CharUnits alignment = getContext().getDeclAlign(&D);
951
952 // If the type is variably-modified, emit all the VLA sizes for it.
953 if (Ty->isVariablyModifiedType())
954 EmitVariablyModifiedType(Ty);
955
956 Address address = Address::invalid();
957 if (Ty->isConstantSizeType()) {
958 bool NRVO = getLangOpts().ElideConstructors &&
959 D.isNRVOVariable();
960
961 // If this value is an array or struct with a statically determinable
962 // constant initializer, there are optimizations we can do.
963 //
964 // TODO: We should constant-evaluate the initializer of any variable,
965 // as long as it is initialized by a constant expression. Currently,
966 // isConstantInitializer produces wrong answers for structs with
967 // reference or bitfield members, and a few other cases, and checking
968 // for POD-ness protects us from some of these.
969 if (D.getInit() && (Ty->isArrayType() || Ty->isRecordType()) &&
970 (D.isConstexpr() ||
971 ((Ty.isPODType(getContext()) ||
972 getContext().getBaseElementType(Ty)->isObjCObjectPointerType()) &&
973 D.getInit()->isConstantInitializer(getContext(), false)))) {
974
975 // If the variable's a const type, and it's neither an NRVO
976 // candidate nor a __block variable and has no mutable members,
977 // emit it as a global instead.
978 if (CGM.getCodeGenOpts().MergeAllConstants && !NRVO && !isByRef &&
979 CGM.isTypeConstant(Ty, true)) {
980 EmitStaticVarDecl(D, llvm::GlobalValue::InternalLinkage);
981
982 // Signal this condition to later callbacks.
983 emission.Addr = Address::invalid();
984 assert(emission.wasEmittedAsGlobal());
985 return emission;
986 }
987
988 // Otherwise, tell the initialization code that we're in this case.
989 emission.IsConstantAggregate = true;
990 }
991
992 // A normal fixed sized variable becomes an alloca in the entry block,
993 // unless it's an NRVO variable.
994
995 if (NRVO) {
996 // The named return value optimization: allocate this variable in the
997 // return slot, so that we can elide the copy when returning this
998 // variable (C++0x [class.copy]p34).
999 address = ReturnValue;
1000
1001 if (const RecordType *RecordTy = Ty->getAs<RecordType>()) {
1002 if (!cast<CXXRecordDecl>(RecordTy->getDecl())->hasTrivialDestructor()) {
1003 // Create a flag that is used to indicate when the NRVO was applied
1004 // to this variable. Set it to zero to indicate that NRVO was not
1005 // applied.
1006 llvm::Value *Zero = Builder.getFalse();
1007 Address NRVOFlag =
1008 CreateTempAlloca(Zero->getType(), CharUnits::One(), "nrvo");
1009 EnsureInsertPoint();
1010 Builder.CreateStore(Zero, NRVOFlag);
1011
1012 // Record the NRVO flag for this variable.
1013 NRVOFlags[&D] = NRVOFlag.getPointer();
1014 emission.NRVOFlag = NRVOFlag.getPointer();
1015 }
1016 }
1017 } else {
1018 CharUnits allocaAlignment;
1019 llvm::Type *allocaTy;
1020 if (isByRef) {
1021 auto &byrefInfo = getBlockByrefInfo(&D);
1022 allocaTy = byrefInfo.Type;
1023 allocaAlignment = byrefInfo.ByrefAlignment;
1024 } else {
1025 allocaTy = ConvertTypeForMem(Ty);
1026 allocaAlignment = alignment;
1027 }
1028
1029 // Create the alloca. Note that we set the name separately from
1030 // building the instruction so that it's there even in no-asserts
1031 // builds.
1032 address = CreateTempAlloca(allocaTy, allocaAlignment);
1033 address.getPointer()->setName(D.getName());
1034
1035 // Don't emit lifetime markers for MSVC catch parameters. The lifetime of
1036 // the catch parameter starts in the catchpad instruction, and we can't
1037 // insert code in those basic blocks.
1038 bool IsMSCatchParam =
1039 D.isExceptionVariable() && getTarget().getCXXABI().isMicrosoft();
1040
1041 // Emit a lifetime intrinsic if meaningful. There's no point
1042 // in doing this if we don't have a valid insertion point (?).
1043 if (HaveInsertPoint() && !IsMSCatchParam) {
1044 uint64_t size = CGM.getDataLayout().getTypeAllocSize(allocaTy);
1045 emission.SizeForLifetimeMarkers =
1046 EmitLifetimeStart(size, address.getPointer());
1047 } else {
1048 assert(!emission.useLifetimeMarkers());
1049 }
1050 }
1051 } else {
1052 EnsureInsertPoint();
1053
1054 if (!DidCallStackSave) {
1055 // Save the stack.
1056 Address Stack =
1057 CreateTempAlloca(Int8PtrTy, getPointerAlign(), "saved_stack");
1058
1059 llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stacksave);
1060 llvm::Value *V = Builder.CreateCall(F);
1061 Builder.CreateStore(V, Stack);
1062
1063 DidCallStackSave = true;
1064
1065 // Push a cleanup block and restore the stack there.
1066 // FIXME: in general circumstances, this should be an EH cleanup.
1067 pushStackRestore(NormalCleanup, Stack);
1068 }
1069
1070 llvm::Value *elementCount;
1071 QualType elementType;
1072 std::tie(elementCount, elementType) = getVLASize(Ty);
1073
1074 llvm::Type *llvmTy = ConvertTypeForMem(elementType);
1075
1076 // Allocate memory for the array.
1077 llvm::AllocaInst *vla = Builder.CreateAlloca(llvmTy, elementCount, "vla");
1078 vla->setAlignment(alignment.getQuantity());
1079
1080 address = Address(vla, alignment);
1081 }
1082
1083 setAddrOfLocalVar(&D, address);
1084 emission.Addr = address;
1085
1086 // Emit debug info for local var declaration.
1087 if (HaveInsertPoint())
1088 if (CGDebugInfo *DI = getDebugInfo()) {
1089 if (CGM.getCodeGenOpts().getDebugInfo()
1090 >= CodeGenOptions::LimitedDebugInfo) {
1091 DI->setLocation(D.getLocation());
1092 DI->EmitDeclareOfAutoVariable(&D, address.getPointer(), Builder);
1093 }
1094 }
1095
1096 if (D.hasAttr<AnnotateAttr>())
1097 EmitVarAnnotations(&D, address.getPointer());
1098
1099 return emission;
1100 }
1101
1102 /// Determines whether the given __block variable is potentially
1103 /// captured by the given expression.
isCapturedBy(const VarDecl & var,const Expr * e)1104 static bool isCapturedBy(const VarDecl &var, const Expr *e) {
1105 // Skip the most common kinds of expressions that make
1106 // hierarchy-walking expensive.
1107 e = e->IgnoreParenCasts();
1108
1109 if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) {
1110 const BlockDecl *block = be->getBlockDecl();
1111 for (const auto &I : block->captures()) {
1112 if (I.getVariable() == &var)
1113 return true;
1114 }
1115
1116 // No need to walk into the subexpressions.
1117 return false;
1118 }
1119
1120 if (const StmtExpr *SE = dyn_cast<StmtExpr>(e)) {
1121 const CompoundStmt *CS = SE->getSubStmt();
1122 for (const auto *BI : CS->body())
1123 if (const auto *E = dyn_cast<Expr>(BI)) {
1124 if (isCapturedBy(var, E))
1125 return true;
1126 }
1127 else if (const auto *DS = dyn_cast<DeclStmt>(BI)) {
1128 // special case declarations
1129 for (const auto *I : DS->decls()) {
1130 if (const auto *VD = dyn_cast<VarDecl>((I))) {
1131 const Expr *Init = VD->getInit();
1132 if (Init && isCapturedBy(var, Init))
1133 return true;
1134 }
1135 }
1136 }
1137 else
1138 // FIXME. Make safe assumption assuming arbitrary statements cause capturing.
1139 // Later, provide code to poke into statements for capture analysis.
1140 return true;
1141 return false;
1142 }
1143
1144 for (const Stmt *SubStmt : e->children())
1145 if (isCapturedBy(var, cast<Expr>(SubStmt)))
1146 return true;
1147
1148 return false;
1149 }
1150
1151 /// \brief Determine whether the given initializer is trivial in the sense
1152 /// that it requires no code to be generated.
isTrivialInitializer(const Expr * Init)1153 bool CodeGenFunction::isTrivialInitializer(const Expr *Init) {
1154 if (!Init)
1155 return true;
1156
1157 if (const CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init))
1158 if (CXXConstructorDecl *Constructor = Construct->getConstructor())
1159 if (Constructor->isTrivial() &&
1160 Constructor->isDefaultConstructor() &&
1161 !Construct->requiresZeroInitialization())
1162 return true;
1163
1164 return false;
1165 }
EmitAutoVarInit(const AutoVarEmission & emission)1166 void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
1167 assert(emission.Variable && "emission was not valid!");
1168
1169 // If this was emitted as a global constant, we're done.
1170 if (emission.wasEmittedAsGlobal()) return;
1171
1172 const VarDecl &D = *emission.Variable;
1173 auto DL = ApplyDebugLocation::CreateDefaultArtificial(*this, D.getLocation());
1174 QualType type = D.getType();
1175
1176 // If this local has an initializer, emit it now.
1177 const Expr *Init = D.getInit();
1178
1179 // If we are at an unreachable point, we don't need to emit the initializer
1180 // unless it contains a label.
1181 if (!HaveInsertPoint()) {
1182 if (!Init || !ContainsLabel(Init)) return;
1183 EnsureInsertPoint();
1184 }
1185
1186 // Initialize the structure of a __block variable.
1187 if (emission.IsByRef)
1188 emitByrefStructureInit(emission);
1189
1190 if (isTrivialInitializer(Init))
1191 return;
1192
1193 // Check whether this is a byref variable that's potentially
1194 // captured and moved by its own initializer. If so, we'll need to
1195 // emit the initializer first, then copy into the variable.
1196 bool capturedByInit = emission.IsByRef && isCapturedBy(D, Init);
1197
1198 Address Loc =
1199 capturedByInit ? emission.Addr : emission.getObjectAddress(*this);
1200
1201 llvm::Constant *constant = nullptr;
1202 if (emission.IsConstantAggregate || D.isConstexpr()) {
1203 assert(!capturedByInit && "constant init contains a capturing block?");
1204 constant = CGM.EmitConstantInit(D, this);
1205 }
1206
1207 if (!constant) {
1208 LValue lv = MakeAddrLValue(Loc, type);
1209 lv.setNonGC(true);
1210 return EmitExprAsInit(Init, &D, lv, capturedByInit);
1211 }
1212
1213 if (!emission.IsConstantAggregate) {
1214 // For simple scalar/complex initialization, store the value directly.
1215 LValue lv = MakeAddrLValue(Loc, type);
1216 lv.setNonGC(true);
1217 return EmitStoreThroughLValue(RValue::get(constant), lv, true);
1218 }
1219
1220 // If this is a simple aggregate initialization, we can optimize it
1221 // in various ways.
1222 bool isVolatile = type.isVolatileQualified();
1223
1224 llvm::Value *SizeVal =
1225 llvm::ConstantInt::get(IntPtrTy,
1226 getContext().getTypeSizeInChars(type).getQuantity());
1227
1228 llvm::Type *BP = Int8PtrTy;
1229 if (Loc.getType() != BP)
1230 Loc = Builder.CreateBitCast(Loc, BP);
1231
1232 // If the initializer is all or mostly zeros, codegen with memset then do
1233 // a few stores afterward.
1234 if (shouldUseMemSetPlusStoresToInitialize(constant,
1235 CGM.getDataLayout().getTypeAllocSize(constant->getType()))) {
1236 Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, 0), SizeVal,
1237 isVolatile);
1238 // Zero and undef don't require a stores.
1239 if (!constant->isNullValue() && !isa<llvm::UndefValue>(constant)) {
1240 Loc = Builder.CreateBitCast(Loc, constant->getType()->getPointerTo());
1241 emitStoresForInitAfterMemset(constant, Loc.getPointer(),
1242 isVolatile, Builder);
1243 }
1244 } else {
1245 // Otherwise, create a temporary global with the initializer then
1246 // memcpy from the global to the alloca.
1247 std::string Name = getStaticDeclName(CGM, D);
1248 llvm::GlobalVariable *GV =
1249 new llvm::GlobalVariable(CGM.getModule(), constant->getType(), true,
1250 llvm::GlobalValue::PrivateLinkage,
1251 constant, Name);
1252 GV->setAlignment(Loc.getAlignment().getQuantity());
1253 GV->setUnnamedAddr(true);
1254
1255 Address SrcPtr = Address(GV, Loc.getAlignment());
1256 if (SrcPtr.getType() != BP)
1257 SrcPtr = Builder.CreateBitCast(SrcPtr, BP);
1258
1259 Builder.CreateMemCpy(Loc, SrcPtr, SizeVal, isVolatile);
1260 }
1261 }
1262
1263 /// Emit an expression as an initializer for a variable at the given
1264 /// location. The expression is not necessarily the normal
1265 /// initializer for the variable, and the address is not necessarily
1266 /// its normal location.
1267 ///
1268 /// \param init the initializing expression
1269 /// \param var the variable to act as if we're initializing
1270 /// \param loc the address to initialize; its type is a pointer
1271 /// to the LLVM mapping of the variable's type
1272 /// \param alignment the alignment of the address
1273 /// \param capturedByInit true if the variable is a __block variable
1274 /// whose address is potentially changed by the initializer
EmitExprAsInit(const Expr * init,const ValueDecl * D,LValue lvalue,bool capturedByInit)1275 void CodeGenFunction::EmitExprAsInit(const Expr *init, const ValueDecl *D,
1276 LValue lvalue, bool capturedByInit) {
1277 QualType type = D->getType();
1278
1279 if (type->isReferenceType()) {
1280 RValue rvalue = EmitReferenceBindingToExpr(init);
1281 if (capturedByInit)
1282 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
1283 EmitStoreThroughLValue(rvalue, lvalue, true);
1284 return;
1285 }
1286 switch (getEvaluationKind(type)) {
1287 case TEK_Scalar:
1288 EmitScalarInit(init, D, lvalue, capturedByInit);
1289 return;
1290 case TEK_Complex: {
1291 ComplexPairTy complex = EmitComplexExpr(init);
1292 if (capturedByInit)
1293 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D));
1294 EmitStoreOfComplex(complex, lvalue, /*init*/ true);
1295 return;
1296 }
1297 case TEK_Aggregate:
1298 if (type->isAtomicType()) {
1299 EmitAtomicInit(const_cast<Expr*>(init), lvalue);
1300 } else {
1301 // TODO: how can we delay here if D is captured by its initializer?
1302 EmitAggExpr(init, AggValueSlot::forLValue(lvalue,
1303 AggValueSlot::IsDestructed,
1304 AggValueSlot::DoesNotNeedGCBarriers,
1305 AggValueSlot::IsNotAliased));
1306 }
1307 return;
1308 }
1309 llvm_unreachable("bad evaluation kind");
1310 }
1311
1312 /// Enter a destroy cleanup for the given local variable.
emitAutoVarTypeCleanup(const CodeGenFunction::AutoVarEmission & emission,QualType::DestructionKind dtorKind)1313 void CodeGenFunction::emitAutoVarTypeCleanup(
1314 const CodeGenFunction::AutoVarEmission &emission,
1315 QualType::DestructionKind dtorKind) {
1316 assert(dtorKind != QualType::DK_none);
1317
1318 // Note that for __block variables, we want to destroy the
1319 // original stack object, not the possibly forwarded object.
1320 Address addr = emission.getObjectAddress(*this);
1321
1322 const VarDecl *var = emission.Variable;
1323 QualType type = var->getType();
1324
1325 CleanupKind cleanupKind = NormalAndEHCleanup;
1326 CodeGenFunction::Destroyer *destroyer = nullptr;
1327
1328 switch (dtorKind) {
1329 case QualType::DK_none:
1330 llvm_unreachable("no cleanup for trivially-destructible variable");
1331
1332 case QualType::DK_cxx_destructor:
1333 // If there's an NRVO flag on the emission, we need a different
1334 // cleanup.
1335 if (emission.NRVOFlag) {
1336 assert(!type->isArrayType());
1337 CXXDestructorDecl *dtor = type->getAsCXXRecordDecl()->getDestructor();
1338 EHStack.pushCleanup<DestroyNRVOVariable>(cleanupKind, addr,
1339 dtor, emission.NRVOFlag);
1340 return;
1341 }
1342 break;
1343
1344 case QualType::DK_objc_strong_lifetime:
1345 // Suppress cleanups for pseudo-strong variables.
1346 if (var->isARCPseudoStrong()) return;
1347
1348 // Otherwise, consider whether to use an EH cleanup or not.
1349 cleanupKind = getARCCleanupKind();
1350
1351 // Use the imprecise destroyer by default.
1352 if (!var->hasAttr<ObjCPreciseLifetimeAttr>())
1353 destroyer = CodeGenFunction::destroyARCStrongImprecise;
1354 break;
1355
1356 case QualType::DK_objc_weak_lifetime:
1357 break;
1358 }
1359
1360 // If we haven't chosen a more specific destroyer, use the default.
1361 if (!destroyer) destroyer = getDestroyer(dtorKind);
1362
1363 // Use an EH cleanup in array destructors iff the destructor itself
1364 // is being pushed as an EH cleanup.
1365 bool useEHCleanup = (cleanupKind & EHCleanup);
1366 EHStack.pushCleanup<DestroyObject>(cleanupKind, addr, type, destroyer,
1367 useEHCleanup);
1368 }
1369
EmitAutoVarCleanups(const AutoVarEmission & emission)1370 void CodeGenFunction::EmitAutoVarCleanups(const AutoVarEmission &emission) {
1371 assert(emission.Variable && "emission was not valid!");
1372
1373 // If this was emitted as a global constant, we're done.
1374 if (emission.wasEmittedAsGlobal()) return;
1375
1376 // If we don't have an insertion point, we're done. Sema prevents
1377 // us from jumping into any of these scopes anyway.
1378 if (!HaveInsertPoint()) return;
1379
1380 const VarDecl &D = *emission.Variable;
1381
1382 // Make sure we call @llvm.lifetime.end. This needs to happen
1383 // *last*, so the cleanup needs to be pushed *first*.
1384 if (emission.useLifetimeMarkers()) {
1385 EHStack.pushCleanup<CallLifetimeEnd>(NormalCleanup,
1386 emission.getAllocatedAddress(),
1387 emission.getSizeForLifetimeMarkers());
1388 EHCleanupScope &cleanup = cast<EHCleanupScope>(*EHStack.begin());
1389 cleanup.setLifetimeMarker();
1390 }
1391
1392 // Check the type for a cleanup.
1393 if (QualType::DestructionKind dtorKind = D.getType().isDestructedType())
1394 emitAutoVarTypeCleanup(emission, dtorKind);
1395
1396 // In GC mode, honor objc_precise_lifetime.
1397 if (getLangOpts().getGC() != LangOptions::NonGC &&
1398 D.hasAttr<ObjCPreciseLifetimeAttr>()) {
1399 EHStack.pushCleanup<ExtendGCLifetime>(NormalCleanup, &D);
1400 }
1401
1402 // Handle the cleanup attribute.
1403 if (const CleanupAttr *CA = D.getAttr<CleanupAttr>()) {
1404 const FunctionDecl *FD = CA->getFunctionDecl();
1405
1406 llvm::Constant *F = CGM.GetAddrOfFunction(FD);
1407 assert(F && "Could not find function!");
1408
1409 const CGFunctionInfo &Info = CGM.getTypes().arrangeFunctionDeclaration(FD);
1410 EHStack.pushCleanup<CallCleanupFunction>(NormalAndEHCleanup, F, &Info, &D);
1411 }
1412
1413 // If this is a block variable, call _Block_object_destroy
1414 // (on the unforwarded address).
1415 if (emission.IsByRef)
1416 enterByrefCleanup(emission);
1417 }
1418
1419 CodeGenFunction::Destroyer *
getDestroyer(QualType::DestructionKind kind)1420 CodeGenFunction::getDestroyer(QualType::DestructionKind kind) {
1421 switch (kind) {
1422 case QualType::DK_none: llvm_unreachable("no destroyer for trivial dtor");
1423 case QualType::DK_cxx_destructor:
1424 return destroyCXXObject;
1425 case QualType::DK_objc_strong_lifetime:
1426 return destroyARCStrongPrecise;
1427 case QualType::DK_objc_weak_lifetime:
1428 return destroyARCWeak;
1429 }
1430 llvm_unreachable("Unknown DestructionKind");
1431 }
1432
1433 /// pushEHDestroy - Push the standard destructor for the given type as
1434 /// an EH-only cleanup.
pushEHDestroy(QualType::DestructionKind dtorKind,Address addr,QualType type)1435 void CodeGenFunction::pushEHDestroy(QualType::DestructionKind dtorKind,
1436 Address addr, QualType type) {
1437 assert(dtorKind && "cannot push destructor for trivial type");
1438 assert(needsEHCleanup(dtorKind));
1439
1440 pushDestroy(EHCleanup, addr, type, getDestroyer(dtorKind), true);
1441 }
1442
1443 /// pushDestroy - Push the standard destructor for the given type as
1444 /// at least a normal cleanup.
pushDestroy(QualType::DestructionKind dtorKind,Address addr,QualType type)1445 void CodeGenFunction::pushDestroy(QualType::DestructionKind dtorKind,
1446 Address addr, QualType type) {
1447 assert(dtorKind && "cannot push destructor for trivial type");
1448
1449 CleanupKind cleanupKind = getCleanupKind(dtorKind);
1450 pushDestroy(cleanupKind, addr, type, getDestroyer(dtorKind),
1451 cleanupKind & EHCleanup);
1452 }
1453
pushDestroy(CleanupKind cleanupKind,Address addr,QualType type,Destroyer * destroyer,bool useEHCleanupForArray)1454 void CodeGenFunction::pushDestroy(CleanupKind cleanupKind, Address addr,
1455 QualType type, Destroyer *destroyer,
1456 bool useEHCleanupForArray) {
1457 pushFullExprCleanup<DestroyObject>(cleanupKind, addr, type,
1458 destroyer, useEHCleanupForArray);
1459 }
1460
pushStackRestore(CleanupKind Kind,Address SPMem)1461 void CodeGenFunction::pushStackRestore(CleanupKind Kind, Address SPMem) {
1462 EHStack.pushCleanup<CallStackRestore>(Kind, SPMem);
1463 }
1464
pushLifetimeExtendedDestroy(CleanupKind cleanupKind,Address addr,QualType type,Destroyer * destroyer,bool useEHCleanupForArray)1465 void CodeGenFunction::pushLifetimeExtendedDestroy(
1466 CleanupKind cleanupKind, Address addr, QualType type,
1467 Destroyer *destroyer, bool useEHCleanupForArray) {
1468 assert(!isInConditionalBranch() &&
1469 "performing lifetime extension from within conditional");
1470
1471 // Push an EH-only cleanup for the object now.
1472 // FIXME: When popping normal cleanups, we need to keep this EH cleanup
1473 // around in case a temporary's destructor throws an exception.
1474 if (cleanupKind & EHCleanup)
1475 EHStack.pushCleanup<DestroyObject>(
1476 static_cast<CleanupKind>(cleanupKind & ~NormalCleanup), addr, type,
1477 destroyer, useEHCleanupForArray);
1478
1479 // Remember that we need to push a full cleanup for the object at the
1480 // end of the full-expression.
1481 pushCleanupAfterFullExpr<DestroyObject>(
1482 cleanupKind, addr, type, destroyer, useEHCleanupForArray);
1483 }
1484
1485 /// emitDestroy - Immediately perform the destruction of the given
1486 /// object.
1487 ///
1488 /// \param addr - the address of the object; a type*
1489 /// \param type - the type of the object; if an array type, all
1490 /// objects are destroyed in reverse order
1491 /// \param destroyer - the function to call to destroy individual
1492 /// elements
1493 /// \param useEHCleanupForArray - whether an EH cleanup should be
1494 /// used when destroying array elements, in case one of the
1495 /// destructions throws an exception
emitDestroy(Address addr,QualType type,Destroyer * destroyer,bool useEHCleanupForArray)1496 void CodeGenFunction::emitDestroy(Address addr, QualType type,
1497 Destroyer *destroyer,
1498 bool useEHCleanupForArray) {
1499 const ArrayType *arrayType = getContext().getAsArrayType(type);
1500 if (!arrayType)
1501 return destroyer(*this, addr, type);
1502
1503 llvm::Value *length = emitArrayLength(arrayType, type, addr);
1504
1505 CharUnits elementAlign =
1506 addr.getAlignment()
1507 .alignmentOfArrayElement(getContext().getTypeSizeInChars(type));
1508
1509 // Normally we have to check whether the array is zero-length.
1510 bool checkZeroLength = true;
1511
1512 // But if the array length is constant, we can suppress that.
1513 if (llvm::ConstantInt *constLength = dyn_cast<llvm::ConstantInt>(length)) {
1514 // ...and if it's constant zero, we can just skip the entire thing.
1515 if (constLength->isZero()) return;
1516 checkZeroLength = false;
1517 }
1518
1519 llvm::Value *begin = addr.getPointer();
1520 llvm::Value *end = Builder.CreateInBoundsGEP(begin, length);
1521 emitArrayDestroy(begin, end, type, elementAlign, destroyer,
1522 checkZeroLength, useEHCleanupForArray);
1523 }
1524
1525 /// emitArrayDestroy - Destroys all the elements of the given array,
1526 /// beginning from last to first. The array cannot be zero-length.
1527 ///
1528 /// \param begin - a type* denoting the first element of the array
1529 /// \param end - a type* denoting one past the end of the array
1530 /// \param elementType - the element type of the array
1531 /// \param destroyer - the function to call to destroy elements
1532 /// \param useEHCleanup - whether to push an EH cleanup to destroy
1533 /// the remaining elements in case the destruction of a single
1534 /// element throws
emitArrayDestroy(llvm::Value * begin,llvm::Value * end,QualType elementType,CharUnits elementAlign,Destroyer * destroyer,bool checkZeroLength,bool useEHCleanup)1535 void CodeGenFunction::emitArrayDestroy(llvm::Value *begin,
1536 llvm::Value *end,
1537 QualType elementType,
1538 CharUnits elementAlign,
1539 Destroyer *destroyer,
1540 bool checkZeroLength,
1541 bool useEHCleanup) {
1542 assert(!elementType->isArrayType());
1543
1544 // The basic structure here is a do-while loop, because we don't
1545 // need to check for the zero-element case.
1546 llvm::BasicBlock *bodyBB = createBasicBlock("arraydestroy.body");
1547 llvm::BasicBlock *doneBB = createBasicBlock("arraydestroy.done");
1548
1549 if (checkZeroLength) {
1550 llvm::Value *isEmpty = Builder.CreateICmpEQ(begin, end,
1551 "arraydestroy.isempty");
1552 Builder.CreateCondBr(isEmpty, doneBB, bodyBB);
1553 }
1554
1555 // Enter the loop body, making that address the current address.
1556 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1557 EmitBlock(bodyBB);
1558 llvm::PHINode *elementPast =
1559 Builder.CreatePHI(begin->getType(), 2, "arraydestroy.elementPast");
1560 elementPast->addIncoming(end, entryBB);
1561
1562 // Shift the address back by one element.
1563 llvm::Value *negativeOne = llvm::ConstantInt::get(SizeTy, -1, true);
1564 llvm::Value *element = Builder.CreateInBoundsGEP(elementPast, negativeOne,
1565 "arraydestroy.element");
1566
1567 if (useEHCleanup)
1568 pushRegularPartialArrayCleanup(begin, element, elementType, elementAlign,
1569 destroyer);
1570
1571 // Perform the actual destruction there.
1572 destroyer(*this, Address(element, elementAlign), elementType);
1573
1574 if (useEHCleanup)
1575 PopCleanupBlock();
1576
1577 // Check whether we've reached the end.
1578 llvm::Value *done = Builder.CreateICmpEQ(element, begin, "arraydestroy.done");
1579 Builder.CreateCondBr(done, doneBB, bodyBB);
1580 elementPast->addIncoming(element, Builder.GetInsertBlock());
1581
1582 // Done.
1583 EmitBlock(doneBB);
1584 }
1585
1586 /// Perform partial array destruction as if in an EH cleanup. Unlike
1587 /// emitArrayDestroy, the element type here may still be an array type.
emitPartialArrayDestroy(CodeGenFunction & CGF,llvm::Value * begin,llvm::Value * end,QualType type,CharUnits elementAlign,CodeGenFunction::Destroyer * destroyer)1588 static void emitPartialArrayDestroy(CodeGenFunction &CGF,
1589 llvm::Value *begin, llvm::Value *end,
1590 QualType type, CharUnits elementAlign,
1591 CodeGenFunction::Destroyer *destroyer) {
1592 // If the element type is itself an array, drill down.
1593 unsigned arrayDepth = 0;
1594 while (const ArrayType *arrayType = CGF.getContext().getAsArrayType(type)) {
1595 // VLAs don't require a GEP index to walk into.
1596 if (!isa<VariableArrayType>(arrayType))
1597 arrayDepth++;
1598 type = arrayType->getElementType();
1599 }
1600
1601 if (arrayDepth) {
1602 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0);
1603
1604 SmallVector<llvm::Value*,4> gepIndices(arrayDepth+1, zero);
1605 begin = CGF.Builder.CreateInBoundsGEP(begin, gepIndices, "pad.arraybegin");
1606 end = CGF.Builder.CreateInBoundsGEP(end, gepIndices, "pad.arrayend");
1607 }
1608
1609 // Destroy the array. We don't ever need an EH cleanup because we
1610 // assume that we're in an EH cleanup ourselves, so a throwing
1611 // destructor causes an immediate terminate.
1612 CGF.emitArrayDestroy(begin, end, type, elementAlign, destroyer,
1613 /*checkZeroLength*/ true, /*useEHCleanup*/ false);
1614 }
1615
1616 namespace {
1617 /// RegularPartialArrayDestroy - a cleanup which performs a partial
1618 /// array destroy where the end pointer is regularly determined and
1619 /// does not need to be loaded from a local.
1620 class RegularPartialArrayDestroy final : public EHScopeStack::Cleanup {
1621 llvm::Value *ArrayBegin;
1622 llvm::Value *ArrayEnd;
1623 QualType ElementType;
1624 CodeGenFunction::Destroyer *Destroyer;
1625 CharUnits ElementAlign;
1626 public:
RegularPartialArrayDestroy(llvm::Value * arrayBegin,llvm::Value * arrayEnd,QualType elementType,CharUnits elementAlign,CodeGenFunction::Destroyer * destroyer)1627 RegularPartialArrayDestroy(llvm::Value *arrayBegin, llvm::Value *arrayEnd,
1628 QualType elementType, CharUnits elementAlign,
1629 CodeGenFunction::Destroyer *destroyer)
1630 : ArrayBegin(arrayBegin), ArrayEnd(arrayEnd),
1631 ElementType(elementType), Destroyer(destroyer),
1632 ElementAlign(elementAlign) {}
1633
Emit(CodeGenFunction & CGF,Flags flags)1634 void Emit(CodeGenFunction &CGF, Flags flags) override {
1635 emitPartialArrayDestroy(CGF, ArrayBegin, ArrayEnd,
1636 ElementType, ElementAlign, Destroyer);
1637 }
1638 };
1639
1640 /// IrregularPartialArrayDestroy - a cleanup which performs a
1641 /// partial array destroy where the end pointer is irregularly
1642 /// determined and must be loaded from a local.
1643 class IrregularPartialArrayDestroy final : public EHScopeStack::Cleanup {
1644 llvm::Value *ArrayBegin;
1645 Address ArrayEndPointer;
1646 QualType ElementType;
1647 CodeGenFunction::Destroyer *Destroyer;
1648 CharUnits ElementAlign;
1649 public:
IrregularPartialArrayDestroy(llvm::Value * arrayBegin,Address arrayEndPointer,QualType elementType,CharUnits elementAlign,CodeGenFunction::Destroyer * destroyer)1650 IrregularPartialArrayDestroy(llvm::Value *arrayBegin,
1651 Address arrayEndPointer,
1652 QualType elementType,
1653 CharUnits elementAlign,
1654 CodeGenFunction::Destroyer *destroyer)
1655 : ArrayBegin(arrayBegin), ArrayEndPointer(arrayEndPointer),
1656 ElementType(elementType), Destroyer(destroyer),
1657 ElementAlign(elementAlign) {}
1658
Emit(CodeGenFunction & CGF,Flags flags)1659 void Emit(CodeGenFunction &CGF, Flags flags) override {
1660 llvm::Value *arrayEnd = CGF.Builder.CreateLoad(ArrayEndPointer);
1661 emitPartialArrayDestroy(CGF, ArrayBegin, arrayEnd,
1662 ElementType, ElementAlign, Destroyer);
1663 }
1664 };
1665 }
1666
1667 /// pushIrregularPartialArrayCleanup - Push an EH cleanup to destroy
1668 /// already-constructed elements of the given array. The cleanup
1669 /// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
1670 ///
1671 /// \param elementType - the immediate element type of the array;
1672 /// possibly still an array type
pushIrregularPartialArrayCleanup(llvm::Value * arrayBegin,Address arrayEndPointer,QualType elementType,CharUnits elementAlign,Destroyer * destroyer)1673 void CodeGenFunction::pushIrregularPartialArrayCleanup(llvm::Value *arrayBegin,
1674 Address arrayEndPointer,
1675 QualType elementType,
1676 CharUnits elementAlign,
1677 Destroyer *destroyer) {
1678 pushFullExprCleanup<IrregularPartialArrayDestroy>(EHCleanup,
1679 arrayBegin, arrayEndPointer,
1680 elementType, elementAlign,
1681 destroyer);
1682 }
1683
1684 /// pushRegularPartialArrayCleanup - Push an EH cleanup to destroy
1685 /// already-constructed elements of the given array. The cleanup
1686 /// may be popped with DeactivateCleanupBlock or PopCleanupBlock.
1687 ///
1688 /// \param elementType - the immediate element type of the array;
1689 /// possibly still an array type
pushRegularPartialArrayCleanup(llvm::Value * arrayBegin,llvm::Value * arrayEnd,QualType elementType,CharUnits elementAlign,Destroyer * destroyer)1690 void CodeGenFunction::pushRegularPartialArrayCleanup(llvm::Value *arrayBegin,
1691 llvm::Value *arrayEnd,
1692 QualType elementType,
1693 CharUnits elementAlign,
1694 Destroyer *destroyer) {
1695 pushFullExprCleanup<RegularPartialArrayDestroy>(EHCleanup,
1696 arrayBegin, arrayEnd,
1697 elementType, elementAlign,
1698 destroyer);
1699 }
1700
1701 /// Lazily declare the @llvm.lifetime.start intrinsic.
getLLVMLifetimeStartFn()1702 llvm::Constant *CodeGenModule::getLLVMLifetimeStartFn() {
1703 if (LifetimeStartFn) return LifetimeStartFn;
1704 LifetimeStartFn = llvm::Intrinsic::getDeclaration(&getModule(),
1705 llvm::Intrinsic::lifetime_start);
1706 return LifetimeStartFn;
1707 }
1708
1709 /// Lazily declare the @llvm.lifetime.end intrinsic.
getLLVMLifetimeEndFn()1710 llvm::Constant *CodeGenModule::getLLVMLifetimeEndFn() {
1711 if (LifetimeEndFn) return LifetimeEndFn;
1712 LifetimeEndFn = llvm::Intrinsic::getDeclaration(&getModule(),
1713 llvm::Intrinsic::lifetime_end);
1714 return LifetimeEndFn;
1715 }
1716
1717 namespace {
1718 /// A cleanup to perform a release of an object at the end of a
1719 /// function. This is used to balance out the incoming +1 of a
1720 /// ns_consumed argument when we can't reasonably do that just by
1721 /// not doing the initial retain for a __block argument.
1722 struct ConsumeARCParameter final : EHScopeStack::Cleanup {
ConsumeARCParameter__anon8923ffa70311::ConsumeARCParameter1723 ConsumeARCParameter(llvm::Value *param,
1724 ARCPreciseLifetime_t precise)
1725 : Param(param), Precise(precise) {}
1726
1727 llvm::Value *Param;
1728 ARCPreciseLifetime_t Precise;
1729
Emit__anon8923ffa70311::ConsumeARCParameter1730 void Emit(CodeGenFunction &CGF, Flags flags) override {
1731 CGF.EmitARCRelease(Param, Precise);
1732 }
1733 };
1734 }
1735
1736 /// Emit an alloca (or GlobalValue depending on target)
1737 /// for the specified parameter and set up LocalDeclMap.
EmitParmDecl(const VarDecl & D,ParamValue Arg,unsigned ArgNo)1738 void CodeGenFunction::EmitParmDecl(const VarDecl &D, ParamValue Arg,
1739 unsigned ArgNo) {
1740 // FIXME: Why isn't ImplicitParamDecl a ParmVarDecl?
1741 assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) &&
1742 "Invalid argument to EmitParmDecl");
1743
1744 Arg.getAnyValue()->setName(D.getName());
1745
1746 QualType Ty = D.getType();
1747
1748 // Use better IR generation for certain implicit parameters.
1749 if (auto IPD = dyn_cast<ImplicitParamDecl>(&D)) {
1750 // The only implicit argument a block has is its literal.
1751 // We assume this is always passed directly.
1752 if (BlockInfo) {
1753 setBlockContextParameter(IPD, ArgNo, Arg.getDirectValue());
1754 return;
1755 }
1756 }
1757
1758 Address DeclPtr = Address::invalid();
1759 bool DoStore = false;
1760 bool IsScalar = hasScalarEvaluationKind(Ty);
1761 // If we already have a pointer to the argument, reuse the input pointer.
1762 if (Arg.isIndirect()) {
1763 DeclPtr = Arg.getIndirectAddress();
1764 // If we have a prettier pointer type at this point, bitcast to that.
1765 unsigned AS = DeclPtr.getType()->getAddressSpace();
1766 llvm::Type *IRTy = ConvertTypeForMem(Ty)->getPointerTo(AS);
1767 if (DeclPtr.getType() != IRTy)
1768 DeclPtr = Builder.CreateBitCast(DeclPtr, IRTy, D.getName());
1769
1770 // Push a destructor cleanup for this parameter if the ABI requires it.
1771 // Don't push a cleanup in a thunk for a method that will also emit a
1772 // cleanup.
1773 if (!IsScalar && !CurFuncIsThunk &&
1774 getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) {
1775 const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
1776 if (RD && RD->hasNonTrivialDestructor())
1777 pushDestroy(QualType::DK_cxx_destructor, DeclPtr, Ty);
1778 }
1779 } else {
1780 // Otherwise, create a temporary to hold the value.
1781 DeclPtr = CreateMemTemp(Ty, getContext().getDeclAlign(&D),
1782 D.getName() + ".addr");
1783 DoStore = true;
1784 }
1785
1786 llvm::Value *ArgVal = (DoStore ? Arg.getDirectValue() : nullptr);
1787
1788 LValue lv = MakeAddrLValue(DeclPtr, Ty);
1789 if (IsScalar) {
1790 Qualifiers qs = Ty.getQualifiers();
1791 if (Qualifiers::ObjCLifetime lt = qs.getObjCLifetime()) {
1792 // We honor __attribute__((ns_consumed)) for types with lifetime.
1793 // For __strong, it's handled by just skipping the initial retain;
1794 // otherwise we have to balance out the initial +1 with an extra
1795 // cleanup to do the release at the end of the function.
1796 bool isConsumed = D.hasAttr<NSConsumedAttr>();
1797
1798 // 'self' is always formally __strong, but if this is not an
1799 // init method then we don't want to retain it.
1800 if (D.isARCPseudoStrong()) {
1801 const ObjCMethodDecl *method = cast<ObjCMethodDecl>(CurCodeDecl);
1802 assert(&D == method->getSelfDecl());
1803 assert(lt == Qualifiers::OCL_Strong);
1804 assert(qs.hasConst());
1805 assert(method->getMethodFamily() != OMF_init);
1806 (void) method;
1807 lt = Qualifiers::OCL_ExplicitNone;
1808 }
1809
1810 if (lt == Qualifiers::OCL_Strong) {
1811 if (!isConsumed) {
1812 if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1813 // use objc_storeStrong(&dest, value) for retaining the
1814 // object. But first, store a null into 'dest' because
1815 // objc_storeStrong attempts to release its old value.
1816 llvm::Value *Null = CGM.EmitNullConstant(D.getType());
1817 EmitStoreOfScalar(Null, lv, /* isInitialization */ true);
1818 EmitARCStoreStrongCall(lv.getAddress(), ArgVal, true);
1819 DoStore = false;
1820 }
1821 else
1822 // Don't use objc_retainBlock for block pointers, because we
1823 // don't want to Block_copy something just because we got it
1824 // as a parameter.
1825 ArgVal = EmitARCRetainNonBlock(ArgVal);
1826 }
1827 } else {
1828 // Push the cleanup for a consumed parameter.
1829 if (isConsumed) {
1830 ARCPreciseLifetime_t precise = (D.hasAttr<ObjCPreciseLifetimeAttr>()
1831 ? ARCPreciseLifetime : ARCImpreciseLifetime);
1832 EHStack.pushCleanup<ConsumeARCParameter>(getARCCleanupKind(), ArgVal,
1833 precise);
1834 }
1835
1836 if (lt == Qualifiers::OCL_Weak) {
1837 EmitARCInitWeak(DeclPtr, ArgVal);
1838 DoStore = false; // The weak init is a store, no need to do two.
1839 }
1840 }
1841
1842 // Enter the cleanup scope.
1843 EmitAutoVarWithLifetime(*this, D, DeclPtr, lt);
1844 }
1845 }
1846
1847 // Store the initial value into the alloca.
1848 if (DoStore)
1849 EmitStoreOfScalar(ArgVal, lv, /* isInitialization */ true);
1850
1851 setAddrOfLocalVar(&D, DeclPtr);
1852
1853 // Emit debug info for param declaration.
1854 if (CGDebugInfo *DI = getDebugInfo()) {
1855 if (CGM.getCodeGenOpts().getDebugInfo()
1856 >= CodeGenOptions::LimitedDebugInfo) {
1857 DI->EmitDeclareOfArgVariable(&D, DeclPtr.getPointer(), ArgNo, Builder);
1858 }
1859 }
1860
1861 if (D.hasAttr<AnnotateAttr>())
1862 EmitVarAnnotations(&D, DeclPtr.getPointer());
1863 }
1864