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 "CGDebugInfo.h" 15#include "CodeGenFunction.h" 16#include "CodeGenModule.h" 17#include "CGOpenCLRuntime.h" 18#include "clang/AST/ASTContext.h" 19#include "clang/AST/CharUnits.h" 20#include "clang/AST/Decl.h" 21#include "clang/AST/DeclObjC.h" 22#include "clang/Basic/SourceManager.h" 23#include "clang/Basic/TargetInfo.h" 24#include "clang/Frontend/CodeGenOptions.h" 25#include "llvm/GlobalVariable.h" 26#include "llvm/Intrinsics.h" 27#include "llvm/Target/TargetData.h" 28#include "llvm/Type.h" 29using namespace clang; 30using namespace CodeGen; 31 32 33void CodeGenFunction::EmitDecl(const Decl &D) { 34 switch (D.getKind()) { 35 case Decl::TranslationUnit: 36 case Decl::Namespace: 37 case Decl::UnresolvedUsingTypename: 38 case Decl::ClassTemplateSpecialization: 39 case Decl::ClassTemplatePartialSpecialization: 40 case Decl::TemplateTypeParm: 41 case Decl::UnresolvedUsingValue: 42 case Decl::NonTypeTemplateParm: 43 case Decl::CXXMethod: 44 case Decl::CXXConstructor: 45 case Decl::CXXDestructor: 46 case Decl::CXXConversion: 47 case Decl::Field: 48 case Decl::IndirectField: 49 case Decl::ObjCIvar: 50 case Decl::ObjCAtDefsField: 51 case Decl::ParmVar: 52 case Decl::ImplicitParam: 53 case Decl::ClassTemplate: 54 case Decl::FunctionTemplate: 55 case Decl::TypeAliasTemplate: 56 case Decl::TemplateTemplateParm: 57 case Decl::ObjCMethod: 58 case Decl::ObjCCategory: 59 case Decl::ObjCProtocol: 60 case Decl::ObjCInterface: 61 case Decl::ObjCCategoryImpl: 62 case Decl::ObjCImplementation: 63 case Decl::ObjCProperty: 64 case Decl::ObjCCompatibleAlias: 65 case Decl::AccessSpec: 66 case Decl::LinkageSpec: 67 case Decl::ObjCPropertyImpl: 68 case Decl::FileScopeAsm: 69 case Decl::Friend: 70 case Decl::FriendTemplate: 71 case Decl::Block: 72 case Decl::ClassScopeFunctionSpecialization: 73 llvm_unreachable("Declaration should not be in declstmts!"); 74 case Decl::Function: // void X(); 75 case Decl::Record: // struct/union/class X; 76 case Decl::Enum: // enum X; 77 case Decl::EnumConstant: // enum ? { X = ? } 78 case Decl::CXXRecord: // struct/union/class X; [C++] 79 case Decl::Using: // using X; [C++] 80 case Decl::UsingShadow: 81 case Decl::UsingDirective: // using namespace X; [C++] 82 case Decl::NamespaceAlias: 83 case Decl::StaticAssert: // static_assert(X, ""); [C++0x] 84 case Decl::Label: // __label__ x; 85 case Decl::Import: 86 // None of these decls require codegen support. 87 return; 88 89 case Decl::Var: { 90 const VarDecl &VD = cast<VarDecl>(D); 91 assert(VD.isLocalVarDecl() && 92 "Should not see file-scope variables inside a function!"); 93 return EmitVarDecl(VD); 94 } 95 96 case Decl::Typedef: // typedef int X; 97 case Decl::TypeAlias: { // using X = int; [C++0x] 98 const TypedefNameDecl &TD = cast<TypedefNameDecl>(D); 99 QualType Ty = TD.getUnderlyingType(); 100 101 if (Ty->isVariablyModifiedType()) 102 EmitVariablyModifiedType(Ty); 103 } 104 } 105} 106 107/// EmitVarDecl - This method handles emission of any variable declaration 108/// inside a function, including static vars etc. 109void CodeGenFunction::EmitVarDecl(const VarDecl &D) { 110 switch (D.getStorageClass()) { 111 case SC_None: 112 case SC_Auto: 113 case SC_Register: 114 return EmitAutoVarDecl(D); 115 case SC_Static: { 116 llvm::GlobalValue::LinkageTypes Linkage = 117 llvm::GlobalValue::InternalLinkage; 118 119 // If the function definition has some sort of weak linkage, its 120 // static variables should also be weak so that they get properly 121 // uniqued. We can't do this in C, though, because there's no 122 // standard way to agree on which variables are the same (i.e. 123 // there's no mangling). 124 if (getContext().getLangOpts().CPlusPlus) 125 if (llvm::GlobalValue::isWeakForLinker(CurFn->getLinkage())) 126 Linkage = CurFn->getLinkage(); 127 128 return EmitStaticVarDecl(D, Linkage); 129 } 130 case SC_Extern: 131 case SC_PrivateExtern: 132 // Don't emit it now, allow it to be emitted lazily on its first use. 133 return; 134 case SC_OpenCLWorkGroupLocal: 135 return CGM.getOpenCLRuntime().EmitWorkGroupLocalVarDecl(*this, D); 136 } 137 138 llvm_unreachable("Unknown storage class"); 139} 140 141static std::string GetStaticDeclName(CodeGenFunction &CGF, const VarDecl &D, 142 const char *Separator) { 143 CodeGenModule &CGM = CGF.CGM; 144 if (CGF.getContext().getLangOpts().CPlusPlus) { 145 StringRef Name = CGM.getMangledName(&D); 146 return Name.str(); 147 } 148 149 std::string ContextName; 150 if (!CGF.CurFuncDecl) { 151 // Better be in a block declared in global scope. 152 const NamedDecl *ND = cast<NamedDecl>(&D); 153 const DeclContext *DC = ND->getDeclContext(); 154 if (const BlockDecl *BD = dyn_cast<BlockDecl>(DC)) { 155 MangleBuffer Name; 156 CGM.getBlockMangledName(GlobalDecl(), Name, BD); 157 ContextName = Name.getString(); 158 } 159 else 160 llvm_unreachable("Unknown context for block static var decl"); 161 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CGF.CurFuncDecl)) { 162 StringRef Name = CGM.getMangledName(FD); 163 ContextName = Name.str(); 164 } else if (isa<ObjCMethodDecl>(CGF.CurFuncDecl)) 165 ContextName = CGF.CurFn->getName(); 166 else 167 llvm_unreachable("Unknown context for static var decl"); 168 169 return ContextName + Separator + D.getNameAsString(); 170} 171 172llvm::GlobalVariable * 173CodeGenFunction::CreateStaticVarDecl(const VarDecl &D, 174 const char *Separator, 175 llvm::GlobalValue::LinkageTypes Linkage) { 176 QualType Ty = D.getType(); 177 assert(Ty->isConstantSizeType() && "VLAs can't be static"); 178 179 // Use the label if the variable is renamed with the asm-label extension. 180 std::string Name; 181 if (D.hasAttr<AsmLabelAttr>()) 182 Name = CGM.getMangledName(&D); 183 else 184 Name = GetStaticDeclName(*this, D, Separator); 185 186 llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(Ty); 187 unsigned AddrSpace = 188 CGM.GetGlobalVarAddressSpace(&D, CGM.getContext().getTargetAddressSpace(Ty)); 189 llvm::GlobalVariable *GV = 190 new llvm::GlobalVariable(CGM.getModule(), LTy, 191 Ty.isConstant(getContext()), Linkage, 192 CGM.EmitNullConstant(D.getType()), Name, 0, 193 llvm::GlobalVariable::NotThreadLocal, 194 AddrSpace); 195 GV->setAlignment(getContext().getDeclAlign(&D).getQuantity()); 196 if (Linkage != llvm::GlobalValue::InternalLinkage) 197 GV->setVisibility(CurFn->getVisibility()); 198 199 if (D.isThreadSpecified()) 200 CGM.setTLSMode(GV, D); 201 202 return GV; 203} 204 205/// hasNontrivialDestruction - Determine whether a type's destruction is 206/// non-trivial. If so, and the variable uses static initialization, we must 207/// register its destructor to run on exit. 208static bool hasNontrivialDestruction(QualType T) { 209 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); 210 return RD && !RD->hasTrivialDestructor(); 211} 212 213/// AddInitializerToStaticVarDecl - Add the initializer for 'D' to the 214/// global variable that has already been created for it. If the initializer 215/// has a different type than GV does, this may free GV and return a different 216/// one. Otherwise it just returns GV. 217llvm::GlobalVariable * 218CodeGenFunction::AddInitializerToStaticVarDecl(const VarDecl &D, 219 llvm::GlobalVariable *GV) { 220 llvm::Constant *Init = CGM.EmitConstantInit(D, this); 221 222 // If constant emission failed, then this should be a C++ static 223 // initializer. 224 if (!Init) { 225 if (!getContext().getLangOpts().CPlusPlus) 226 CGM.ErrorUnsupported(D.getInit(), "constant l-value expression"); 227 else if (Builder.GetInsertBlock()) { 228 // Since we have a static initializer, this global variable can't 229 // be constant. 230 GV->setConstant(false); 231 232 EmitCXXGuardedInit(D, GV, /*PerformInit*/true); 233 } 234 return GV; 235 } 236 237 // The initializer may differ in type from the global. Rewrite 238 // the global to match the initializer. (We have to do this 239 // because some types, like unions, can't be completely represented 240 // in the LLVM type system.) 241 if (GV->getType()->getElementType() != Init->getType()) { 242 llvm::GlobalVariable *OldGV = GV; 243 244 GV = new llvm::GlobalVariable(CGM.getModule(), Init->getType(), 245 OldGV->isConstant(), 246 OldGV->getLinkage(), Init, "", 247 /*InsertBefore*/ OldGV, 248 OldGV->getThreadLocalMode(), 249 CGM.getContext().getTargetAddressSpace(D.getType())); 250 GV->setVisibility(OldGV->getVisibility()); 251 252 // Steal the name of the old global 253 GV->takeName(OldGV); 254 255 // Replace all uses of the old global with the new global 256 llvm::Constant *NewPtrForOldDecl = 257 llvm::ConstantExpr::getBitCast(GV, OldGV->getType()); 258 OldGV->replaceAllUsesWith(NewPtrForOldDecl); 259 260 // Erase the old global, since it is no longer used. 261 OldGV->eraseFromParent(); 262 } 263 264 GV->setConstant(CGM.isTypeConstant(D.getType(), true)); 265 GV->setInitializer(Init); 266 267 if (hasNontrivialDestruction(D.getType())) { 268 // We have a constant initializer, but a nontrivial destructor. We still 269 // need to perform a guarded "initialization" in order to register the 270 // destructor. 271 EmitCXXGuardedInit(D, GV, /*PerformInit*/false); 272 } 273 274 return GV; 275} 276 277void CodeGenFunction::EmitStaticVarDecl(const VarDecl &D, 278 llvm::GlobalValue::LinkageTypes Linkage) { 279 llvm::Value *&DMEntry = LocalDeclMap[&D]; 280 assert(DMEntry == 0 && "Decl already exists in localdeclmap!"); 281 282 // Check to see if we already have a global variable for this 283 // declaration. This can happen when double-emitting function 284 // bodies, e.g. with complete and base constructors. 285 llvm::Constant *addr = 286 CGM.getStaticLocalDeclAddress(&D); 287 288 llvm::GlobalVariable *var; 289 if (addr) { 290 var = cast<llvm::GlobalVariable>(addr->stripPointerCasts()); 291 } else { 292 addr = var = CreateStaticVarDecl(D, ".", Linkage); 293 } 294 295 // Store into LocalDeclMap before generating initializer to handle 296 // circular references. 297 DMEntry = addr; 298 CGM.setStaticLocalDeclAddress(&D, addr); 299 300 // We can't have a VLA here, but we can have a pointer to a VLA, 301 // even though that doesn't really make any sense. 302 // Make sure to evaluate VLA bounds now so that we have them for later. 303 if (D.getType()->isVariablyModifiedType()) 304 EmitVariablyModifiedType(D.getType()); 305 306 // Save the type in case adding the initializer forces a type change. 307 llvm::Type *expectedType = addr->getType(); 308 309 // If this value has an initializer, emit it. 310 if (D.getInit()) 311 var = AddInitializerToStaticVarDecl(D, var); 312 313 var->setAlignment(getContext().getDeclAlign(&D).getQuantity()); 314 315 if (D.hasAttr<AnnotateAttr>()) 316 CGM.AddGlobalAnnotations(&D, var); 317 318 if (const SectionAttr *SA = D.getAttr<SectionAttr>()) 319 var->setSection(SA->getName()); 320 321 if (D.hasAttr<UsedAttr>()) 322 CGM.AddUsedGlobal(var); 323 324 // We may have to cast the constant because of the initializer 325 // mismatch above. 326 // 327 // FIXME: It is really dangerous to store this in the map; if anyone 328 // RAUW's the GV uses of this constant will be invalid. 329 llvm::Constant *castedAddr = llvm::ConstantExpr::getBitCast(var, expectedType); 330 DMEntry = castedAddr; 331 CGM.setStaticLocalDeclAddress(&D, castedAddr); 332 333 // Emit global variable debug descriptor for static vars. 334 CGDebugInfo *DI = getDebugInfo(); 335 if (DI && 336 CGM.getCodeGenOpts().DebugInfo >= CodeGenOptions::LimitedDebugInfo) { 337 DI->setLocation(D.getLocation()); 338 DI->EmitGlobalVariable(var, &D); 339 } 340} 341 342namespace { 343 struct DestroyObject : EHScopeStack::Cleanup { 344 DestroyObject(llvm::Value *addr, QualType type, 345 CodeGenFunction::Destroyer *destroyer, 346 bool useEHCleanupForArray) 347 : addr(addr), type(type), destroyer(destroyer), 348 useEHCleanupForArray(useEHCleanupForArray) {} 349 350 llvm::Value *addr; 351 QualType type; 352 CodeGenFunction::Destroyer *destroyer; 353 bool useEHCleanupForArray; 354 355 void Emit(CodeGenFunction &CGF, Flags flags) { 356 // Don't use an EH cleanup recursively from an EH cleanup. 357 bool useEHCleanupForArray = 358 flags.isForNormalCleanup() && this->useEHCleanupForArray; 359 360 CGF.emitDestroy(addr, type, destroyer, useEHCleanupForArray); 361 } 362 }; 363 364 struct DestroyNRVOVariable : EHScopeStack::Cleanup { 365 DestroyNRVOVariable(llvm::Value *addr, 366 const CXXDestructorDecl *Dtor, 367 llvm::Value *NRVOFlag) 368 : Dtor(Dtor), NRVOFlag(NRVOFlag), Loc(addr) {} 369 370 const CXXDestructorDecl *Dtor; 371 llvm::Value *NRVOFlag; 372 llvm::Value *Loc; 373 374 void Emit(CodeGenFunction &CGF, Flags flags) { 375 // Along the exceptions path we always execute the dtor. 376 bool NRVO = flags.isForNormalCleanup() && NRVOFlag; 377 378 llvm::BasicBlock *SkipDtorBB = 0; 379 if (NRVO) { 380 // If we exited via NRVO, we skip the destructor call. 381 llvm::BasicBlock *RunDtorBB = CGF.createBasicBlock("nrvo.unused"); 382 SkipDtorBB = CGF.createBasicBlock("nrvo.skipdtor"); 383 llvm::Value *DidNRVO = CGF.Builder.CreateLoad(NRVOFlag, "nrvo.val"); 384 CGF.Builder.CreateCondBr(DidNRVO, SkipDtorBB, RunDtorBB); 385 CGF.EmitBlock(RunDtorBB); 386 } 387 388 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, 389 /*ForVirtualBase=*/false, Loc); 390 391 if (NRVO) CGF.EmitBlock(SkipDtorBB); 392 } 393 }; 394 395 struct CallStackRestore : EHScopeStack::Cleanup { 396 llvm::Value *Stack; 397 CallStackRestore(llvm::Value *Stack) : Stack(Stack) {} 398 void Emit(CodeGenFunction &CGF, Flags flags) { 399 llvm::Value *V = CGF.Builder.CreateLoad(Stack); 400 llvm::Value *F = CGF.CGM.getIntrinsic(llvm::Intrinsic::stackrestore); 401 CGF.Builder.CreateCall(F, V); 402 } 403 }; 404 405 struct ExtendGCLifetime : EHScopeStack::Cleanup { 406 const VarDecl &Var; 407 ExtendGCLifetime(const VarDecl *var) : Var(*var) {} 408 409 void Emit(CodeGenFunction &CGF, Flags flags) { 410 // Compute the address of the local variable, in case it's a 411 // byref or something. 412 DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false, 413 Var.getType(), VK_LValue, SourceLocation()); 414 llvm::Value *value = CGF.EmitLoadOfScalar(CGF.EmitDeclRefLValue(&DRE)); 415 CGF.EmitExtendGCLifetime(value); 416 } 417 }; 418 419 struct CallCleanupFunction : EHScopeStack::Cleanup { 420 llvm::Constant *CleanupFn; 421 const CGFunctionInfo &FnInfo; 422 const VarDecl &Var; 423 424 CallCleanupFunction(llvm::Constant *CleanupFn, const CGFunctionInfo *Info, 425 const VarDecl *Var) 426 : CleanupFn(CleanupFn), FnInfo(*Info), Var(*Var) {} 427 428 void Emit(CodeGenFunction &CGF, Flags flags) { 429 DeclRefExpr DRE(const_cast<VarDecl*>(&Var), false, 430 Var.getType(), VK_LValue, SourceLocation()); 431 // Compute the address of the local variable, in case it's a byref 432 // or something. 433 llvm::Value *Addr = CGF.EmitDeclRefLValue(&DRE).getAddress(); 434 435 // In some cases, the type of the function argument will be different from 436 // the type of the pointer. An example of this is 437 // void f(void* arg); 438 // __attribute__((cleanup(f))) void *g; 439 // 440 // To fix this we insert a bitcast here. 441 QualType ArgTy = FnInfo.arg_begin()->type; 442 llvm::Value *Arg = 443 CGF.Builder.CreateBitCast(Addr, CGF.ConvertType(ArgTy)); 444 445 CallArgList Args; 446 Args.add(RValue::get(Arg), 447 CGF.getContext().getPointerType(Var.getType())); 448 CGF.EmitCall(FnInfo, CleanupFn, ReturnValueSlot(), Args); 449 } 450 }; 451} 452 453/// EmitAutoVarWithLifetime - Does the setup required for an automatic 454/// variable with lifetime. 455static void EmitAutoVarWithLifetime(CodeGenFunction &CGF, const VarDecl &var, 456 llvm::Value *addr, 457 Qualifiers::ObjCLifetime lifetime) { 458 switch (lifetime) { 459 case Qualifiers::OCL_None: 460 llvm_unreachable("present but none"); 461 462 case Qualifiers::OCL_ExplicitNone: 463 // nothing to do 464 break; 465 466 case Qualifiers::OCL_Strong: { 467 CodeGenFunction::Destroyer *destroyer = 468 (var.hasAttr<ObjCPreciseLifetimeAttr>() 469 ? CodeGenFunction::destroyARCStrongPrecise 470 : CodeGenFunction::destroyARCStrongImprecise); 471 472 CleanupKind cleanupKind = CGF.getARCCleanupKind(); 473 CGF.pushDestroy(cleanupKind, addr, var.getType(), destroyer, 474 cleanupKind & EHCleanup); 475 break; 476 } 477 case Qualifiers::OCL_Autoreleasing: 478 // nothing to do 479 break; 480 481 case Qualifiers::OCL_Weak: 482 // __weak objects always get EH cleanups; otherwise, exceptions 483 // could cause really nasty crashes instead of mere leaks. 484 CGF.pushDestroy(NormalAndEHCleanup, addr, var.getType(), 485 CodeGenFunction::destroyARCWeak, 486 /*useEHCleanup*/ true); 487 break; 488 } 489} 490 491static bool isAccessedBy(const VarDecl &var, const Stmt *s) { 492 if (const Expr *e = dyn_cast<Expr>(s)) { 493 // Skip the most common kinds of expressions that make 494 // hierarchy-walking expensive. 495 s = e = e->IgnoreParenCasts(); 496 497 if (const DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) 498 return (ref->getDecl() == &var); 499 if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) { 500 const BlockDecl *block = be->getBlockDecl(); 501 for (BlockDecl::capture_const_iterator i = block->capture_begin(), 502 e = block->capture_end(); i != e; ++i) { 503 if (i->getVariable() == &var) 504 return true; 505 } 506 } 507 } 508 509 for (Stmt::const_child_range children = s->children(); children; ++children) 510 // children might be null; as in missing decl or conditional of an if-stmt. 511 if ((*children) && isAccessedBy(var, *children)) 512 return true; 513 514 return false; 515} 516 517static bool isAccessedBy(const ValueDecl *decl, const Expr *e) { 518 if (!decl) return false; 519 if (!isa<VarDecl>(decl)) return false; 520 const VarDecl *var = cast<VarDecl>(decl); 521 return isAccessedBy(*var, e); 522} 523 524static void drillIntoBlockVariable(CodeGenFunction &CGF, 525 LValue &lvalue, 526 const VarDecl *var) { 527 lvalue.setAddress(CGF.BuildBlockByrefAddress(lvalue.getAddress(), var)); 528} 529 530void CodeGenFunction::EmitScalarInit(const Expr *init, 531 const ValueDecl *D, 532 LValue lvalue, 533 bool capturedByInit) { 534 Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime(); 535 if (!lifetime) { 536 llvm::Value *value = EmitScalarExpr(init); 537 if (capturedByInit) 538 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D)); 539 EmitStoreThroughLValue(RValue::get(value), lvalue, true); 540 return; 541 } 542 543 // If we're emitting a value with lifetime, we have to do the 544 // initialization *before* we leave the cleanup scopes. 545 if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(init)) { 546 enterFullExpression(ewc); 547 init = ewc->getSubExpr(); 548 } 549 CodeGenFunction::RunCleanupsScope Scope(*this); 550 551 // We have to maintain the illusion that the variable is 552 // zero-initialized. If the variable might be accessed in its 553 // initializer, zero-initialize before running the initializer, then 554 // actually perform the initialization with an assign. 555 bool accessedByInit = false; 556 if (lifetime != Qualifiers::OCL_ExplicitNone) 557 accessedByInit = (capturedByInit || isAccessedBy(D, init)); 558 if (accessedByInit) { 559 LValue tempLV = lvalue; 560 // Drill down to the __block object if necessary. 561 if (capturedByInit) { 562 // We can use a simple GEP for this because it can't have been 563 // moved yet. 564 tempLV.setAddress(Builder.CreateStructGEP(tempLV.getAddress(), 565 getByRefValueLLVMField(cast<VarDecl>(D)))); 566 } 567 568 llvm::PointerType *ty 569 = cast<llvm::PointerType>(tempLV.getAddress()->getType()); 570 ty = cast<llvm::PointerType>(ty->getElementType()); 571 572 llvm::Value *zero = llvm::ConstantPointerNull::get(ty); 573 574 // If __weak, we want to use a barrier under certain conditions. 575 if (lifetime == Qualifiers::OCL_Weak) 576 EmitARCInitWeak(tempLV.getAddress(), zero); 577 578 // Otherwise just do a simple store. 579 else 580 EmitStoreOfScalar(zero, tempLV, /* isInitialization */ true); 581 } 582 583 // Emit the initializer. 584 llvm::Value *value = 0; 585 586 switch (lifetime) { 587 case Qualifiers::OCL_None: 588 llvm_unreachable("present but none"); 589 590 case Qualifiers::OCL_ExplicitNone: 591 // nothing to do 592 value = EmitScalarExpr(init); 593 break; 594 595 case Qualifiers::OCL_Strong: { 596 value = EmitARCRetainScalarExpr(init); 597 break; 598 } 599 600 case Qualifiers::OCL_Weak: { 601 // No way to optimize a producing initializer into this. It's not 602 // worth optimizing for, because the value will immediately 603 // disappear in the common case. 604 value = EmitScalarExpr(init); 605 606 if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D)); 607 if (accessedByInit) 608 EmitARCStoreWeak(lvalue.getAddress(), value, /*ignored*/ true); 609 else 610 EmitARCInitWeak(lvalue.getAddress(), value); 611 return; 612 } 613 614 case Qualifiers::OCL_Autoreleasing: 615 value = EmitARCRetainAutoreleaseScalarExpr(init); 616 break; 617 } 618 619 if (capturedByInit) drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D)); 620 621 // If the variable might have been accessed by its initializer, we 622 // might have to initialize with a barrier. We have to do this for 623 // both __weak and __strong, but __weak got filtered out above. 624 if (accessedByInit && lifetime == Qualifiers::OCL_Strong) { 625 llvm::Value *oldValue = EmitLoadOfScalar(lvalue); 626 EmitStoreOfScalar(value, lvalue, /* isInitialization */ true); 627 EmitARCRelease(oldValue, /*precise*/ false); 628 return; 629 } 630 631 EmitStoreOfScalar(value, lvalue, /* isInitialization */ true); 632} 633 634/// EmitScalarInit - Initialize the given lvalue with the given object. 635void CodeGenFunction::EmitScalarInit(llvm::Value *init, LValue lvalue) { 636 Qualifiers::ObjCLifetime lifetime = lvalue.getObjCLifetime(); 637 if (!lifetime) 638 return EmitStoreThroughLValue(RValue::get(init), lvalue, true); 639 640 switch (lifetime) { 641 case Qualifiers::OCL_None: 642 llvm_unreachable("present but none"); 643 644 case Qualifiers::OCL_ExplicitNone: 645 // nothing to do 646 break; 647 648 case Qualifiers::OCL_Strong: 649 init = EmitARCRetain(lvalue.getType(), init); 650 break; 651 652 case Qualifiers::OCL_Weak: 653 // Initialize and then skip the primitive store. 654 EmitARCInitWeak(lvalue.getAddress(), init); 655 return; 656 657 case Qualifiers::OCL_Autoreleasing: 658 init = EmitARCRetainAutorelease(lvalue.getType(), init); 659 break; 660 } 661 662 EmitStoreOfScalar(init, lvalue, /* isInitialization */ true); 663} 664 665/// canEmitInitWithFewStoresAfterMemset - Decide whether we can emit the 666/// non-zero parts of the specified initializer with equal or fewer than 667/// NumStores scalar stores. 668static bool canEmitInitWithFewStoresAfterMemset(llvm::Constant *Init, 669 unsigned &NumStores) { 670 // Zero and Undef never requires any extra stores. 671 if (isa<llvm::ConstantAggregateZero>(Init) || 672 isa<llvm::ConstantPointerNull>(Init) || 673 isa<llvm::UndefValue>(Init)) 674 return true; 675 if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) || 676 isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) || 677 isa<llvm::ConstantExpr>(Init)) 678 return Init->isNullValue() || NumStores--; 679 680 // See if we can emit each element. 681 if (isa<llvm::ConstantArray>(Init) || isa<llvm::ConstantStruct>(Init)) { 682 for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) { 683 llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i)); 684 if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores)) 685 return false; 686 } 687 return true; 688 } 689 690 if (llvm::ConstantDataSequential *CDS = 691 dyn_cast<llvm::ConstantDataSequential>(Init)) { 692 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) { 693 llvm::Constant *Elt = CDS->getElementAsConstant(i); 694 if (!canEmitInitWithFewStoresAfterMemset(Elt, NumStores)) 695 return false; 696 } 697 return true; 698 } 699 700 // Anything else is hard and scary. 701 return false; 702} 703 704/// emitStoresForInitAfterMemset - For inits that 705/// canEmitInitWithFewStoresAfterMemset returned true for, emit the scalar 706/// stores that would be required. 707static void emitStoresForInitAfterMemset(llvm::Constant *Init, llvm::Value *Loc, 708 bool isVolatile, CGBuilderTy &Builder) { 709 assert(!Init->isNullValue() && !isa<llvm::UndefValue>(Init) && 710 "called emitStoresForInitAfterMemset for zero or undef value."); 711 712 if (isa<llvm::ConstantInt>(Init) || isa<llvm::ConstantFP>(Init) || 713 isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) || 714 isa<llvm::ConstantExpr>(Init)) { 715 Builder.CreateStore(Init, Loc, isVolatile); 716 return; 717 } 718 719 if (llvm::ConstantDataSequential *CDS = 720 dyn_cast<llvm::ConstantDataSequential>(Init)) { 721 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) { 722 llvm::Constant *Elt = CDS->getElementAsConstant(i); 723 724 // If necessary, get a pointer to the element and emit it. 725 if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt)) 726 emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i), 727 isVolatile, Builder); 728 } 729 return; 730 } 731 732 assert((isa<llvm::ConstantStruct>(Init) || isa<llvm::ConstantArray>(Init)) && 733 "Unknown value type!"); 734 735 for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) { 736 llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i)); 737 738 // If necessary, get a pointer to the element and emit it. 739 if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt)) 740 emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i), 741 isVolatile, Builder); 742 } 743} 744 745 746/// shouldUseMemSetPlusStoresToInitialize - Decide whether we should use memset 747/// plus some stores to initialize a local variable instead of using a memcpy 748/// from a constant global. It is beneficial to use memset if the global is all 749/// zeros, or mostly zeros and large. 750static bool shouldUseMemSetPlusStoresToInitialize(llvm::Constant *Init, 751 uint64_t GlobalSize) { 752 // If a global is all zeros, always use a memset. 753 if (isa<llvm::ConstantAggregateZero>(Init)) return true; 754 755 756 // If a non-zero global is <= 32 bytes, always use a memcpy. If it is large, 757 // do it if it will require 6 or fewer scalar stores. 758 // TODO: Should budget depends on the size? Avoiding a large global warrants 759 // plopping in more stores. 760 unsigned StoreBudget = 6; 761 uint64_t SizeLimit = 32; 762 763 return GlobalSize > SizeLimit && 764 canEmitInitWithFewStoresAfterMemset(Init, StoreBudget); 765} 766 767 768/// EmitAutoVarDecl - Emit code and set up an entry in LocalDeclMap for a 769/// variable declaration with auto, register, or no storage class specifier. 770/// These turn into simple stack objects, or GlobalValues depending on target. 771void CodeGenFunction::EmitAutoVarDecl(const VarDecl &D) { 772 AutoVarEmission emission = EmitAutoVarAlloca(D); 773 EmitAutoVarInit(emission); 774 EmitAutoVarCleanups(emission); 775} 776 777/// EmitAutoVarAlloca - Emit the alloca and debug information for a 778/// local variable. Does not emit initalization or destruction. 779CodeGenFunction::AutoVarEmission 780CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) { 781 QualType Ty = D.getType(); 782 783 AutoVarEmission emission(D); 784 785 bool isByRef = D.hasAttr<BlocksAttr>(); 786 emission.IsByRef = isByRef; 787 788 CharUnits alignment = getContext().getDeclAlign(&D); 789 emission.Alignment = alignment; 790 791 // If the type is variably-modified, emit all the VLA sizes for it. 792 if (Ty->isVariablyModifiedType()) 793 EmitVariablyModifiedType(Ty); 794 795 llvm::Value *DeclPtr; 796 if (Ty->isConstantSizeType()) { 797 if (!Target.useGlobalsForAutomaticVariables()) { 798 bool NRVO = getContext().getLangOpts().ElideConstructors && 799 D.isNRVOVariable(); 800 801 // If this value is a POD array or struct with a statically 802 // determinable constant initializer, there are optimizations we can do. 803 // 804 // TODO: We should constant-evaluate the initializer of any variable, 805 // as long as it is initialized by a constant expression. Currently, 806 // isConstantInitializer produces wrong answers for structs with 807 // reference or bitfield members, and a few other cases, and checking 808 // for POD-ness protects us from some of these. 809 if (D.getInit() && 810 (Ty->isArrayType() || Ty->isRecordType()) && 811 (Ty.isPODType(getContext()) || 812 getContext().getBaseElementType(Ty)->isObjCObjectPointerType()) && 813 D.getInit()->isConstantInitializer(getContext(), false)) { 814 815 // If the variable's a const type, and it's neither an NRVO 816 // candidate nor a __block variable and has no mutable members, 817 // emit it as a global instead. 818 if (CGM.getCodeGenOpts().MergeAllConstants && !NRVO && !isByRef && 819 CGM.isTypeConstant(Ty, true)) { 820 EmitStaticVarDecl(D, llvm::GlobalValue::InternalLinkage); 821 822 emission.Address = 0; // signal this condition to later callbacks 823 assert(emission.wasEmittedAsGlobal()); 824 return emission; 825 } 826 827 // Otherwise, tell the initialization code that we're in this case. 828 emission.IsConstantAggregate = true; 829 } 830 831 // A normal fixed sized variable becomes an alloca in the entry block, 832 // unless it's an NRVO variable. 833 llvm::Type *LTy = ConvertTypeForMem(Ty); 834 835 if (NRVO) { 836 // The named return value optimization: allocate this variable in the 837 // return slot, so that we can elide the copy when returning this 838 // variable (C++0x [class.copy]p34). 839 DeclPtr = ReturnValue; 840 841 if (const RecordType *RecordTy = Ty->getAs<RecordType>()) { 842 if (!cast<CXXRecordDecl>(RecordTy->getDecl())->hasTrivialDestructor()) { 843 // Create a flag that is used to indicate when the NRVO was applied 844 // to this variable. Set it to zero to indicate that NRVO was not 845 // applied. 846 llvm::Value *Zero = Builder.getFalse(); 847 llvm::Value *NRVOFlag = CreateTempAlloca(Zero->getType(), "nrvo"); 848 EnsureInsertPoint(); 849 Builder.CreateStore(Zero, NRVOFlag); 850 851 // Record the NRVO flag for this variable. 852 NRVOFlags[&D] = NRVOFlag; 853 emission.NRVOFlag = NRVOFlag; 854 } 855 } 856 } else { 857 if (isByRef) 858 LTy = BuildByRefType(&D); 859 860 llvm::AllocaInst *Alloc = CreateTempAlloca(LTy); 861 Alloc->setName(D.getName()); 862 863 CharUnits allocaAlignment = alignment; 864 if (isByRef) 865 allocaAlignment = std::max(allocaAlignment, 866 getContext().toCharUnitsFromBits(Target.getPointerAlign(0))); 867 Alloc->setAlignment(allocaAlignment.getQuantity()); 868 DeclPtr = Alloc; 869 } 870 } else { 871 // Targets that don't support recursion emit locals as globals. 872 const char *Class = 873 D.getStorageClass() == SC_Register ? ".reg." : ".auto."; 874 DeclPtr = CreateStaticVarDecl(D, Class, 875 llvm::GlobalValue::InternalLinkage); 876 } 877 } else { 878 EnsureInsertPoint(); 879 880 if (!DidCallStackSave) { 881 // Save the stack. 882 llvm::Value *Stack = CreateTempAlloca(Int8PtrTy, "saved_stack"); 883 884 llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stacksave); 885 llvm::Value *V = Builder.CreateCall(F); 886 887 Builder.CreateStore(V, Stack); 888 889 DidCallStackSave = true; 890 891 // Push a cleanup block and restore the stack there. 892 // FIXME: in general circumstances, this should be an EH cleanup. 893 EHStack.pushCleanup<CallStackRestore>(NormalCleanup, Stack); 894 } 895 896 llvm::Value *elementCount; 897 QualType elementType; 898 llvm::tie(elementCount, elementType) = getVLASize(Ty); 899 900 llvm::Type *llvmTy = ConvertTypeForMem(elementType); 901 902 // Allocate memory for the array. 903 llvm::AllocaInst *vla = Builder.CreateAlloca(llvmTy, elementCount, "vla"); 904 vla->setAlignment(alignment.getQuantity()); 905 906 DeclPtr = vla; 907 } 908 909 llvm::Value *&DMEntry = LocalDeclMap[&D]; 910 assert(DMEntry == 0 && "Decl already exists in localdeclmap!"); 911 DMEntry = DeclPtr; 912 emission.Address = DeclPtr; 913 914 // Emit debug info for local var declaration. 915 if (HaveInsertPoint()) 916 if (CGDebugInfo *DI = getDebugInfo()) { 917 if (CGM.getCodeGenOpts().DebugInfo >= CodeGenOptions::LimitedDebugInfo) { 918 DI->setLocation(D.getLocation()); 919 if (Target.useGlobalsForAutomaticVariables()) { 920 DI->EmitGlobalVariable(static_cast<llvm::GlobalVariable *>(DeclPtr), 921 &D); 922 } else 923 DI->EmitDeclareOfAutoVariable(&D, DeclPtr, Builder); 924 } 925 } 926 927 if (D.hasAttr<AnnotateAttr>()) 928 EmitVarAnnotations(&D, emission.Address); 929 930 return emission; 931} 932 933/// Determines whether the given __block variable is potentially 934/// captured by the given expression. 935static bool isCapturedBy(const VarDecl &var, const Expr *e) { 936 // Skip the most common kinds of expressions that make 937 // hierarchy-walking expensive. 938 e = e->IgnoreParenCasts(); 939 940 if (const BlockExpr *be = dyn_cast<BlockExpr>(e)) { 941 const BlockDecl *block = be->getBlockDecl(); 942 for (BlockDecl::capture_const_iterator i = block->capture_begin(), 943 e = block->capture_end(); i != e; ++i) { 944 if (i->getVariable() == &var) 945 return true; 946 } 947 948 // No need to walk into the subexpressions. 949 return false; 950 } 951 952 if (const StmtExpr *SE = dyn_cast<StmtExpr>(e)) { 953 const CompoundStmt *CS = SE->getSubStmt(); 954 for (CompoundStmt::const_body_iterator BI = CS->body_begin(), 955 BE = CS->body_end(); BI != BE; ++BI) 956 if (Expr *E = dyn_cast<Expr>((*BI))) { 957 if (isCapturedBy(var, E)) 958 return true; 959 } 960 else if (DeclStmt *DS = dyn_cast<DeclStmt>((*BI))) { 961 // special case declarations 962 for (DeclStmt::decl_iterator I = DS->decl_begin(), E = DS->decl_end(); 963 I != E; ++I) { 964 if (VarDecl *VD = dyn_cast<VarDecl>((*I))) { 965 Expr *Init = VD->getInit(); 966 if (Init && isCapturedBy(var, Init)) 967 return true; 968 } 969 } 970 } 971 else 972 // FIXME. Make safe assumption assuming arbitrary statements cause capturing. 973 // Later, provide code to poke into statements for capture analysis. 974 return true; 975 return false; 976 } 977 978 for (Stmt::const_child_range children = e->children(); children; ++children) 979 if (isCapturedBy(var, cast<Expr>(*children))) 980 return true; 981 982 return false; 983} 984 985/// \brief Determine whether the given initializer is trivial in the sense 986/// that it requires no code to be generated. 987static bool isTrivialInitializer(const Expr *Init) { 988 if (!Init) 989 return true; 990 991 if (const CXXConstructExpr *Construct = dyn_cast<CXXConstructExpr>(Init)) 992 if (CXXConstructorDecl *Constructor = Construct->getConstructor()) 993 if (Constructor->isTrivial() && 994 Constructor->isDefaultConstructor() && 995 !Construct->requiresZeroInitialization()) 996 return true; 997 998 return false; 999} 1000void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) { 1001 assert(emission.Variable && "emission was not valid!"); 1002 1003 // If this was emitted as a global constant, we're done. 1004 if (emission.wasEmittedAsGlobal()) return; 1005 1006 const VarDecl &D = *emission.Variable; 1007 QualType type = D.getType(); 1008 1009 // If this local has an initializer, emit it now. 1010 const Expr *Init = D.getInit(); 1011 1012 // If we are at an unreachable point, we don't need to emit the initializer 1013 // unless it contains a label. 1014 if (!HaveInsertPoint()) { 1015 if (!Init || !ContainsLabel(Init)) return; 1016 EnsureInsertPoint(); 1017 } 1018 1019 // Initialize the structure of a __block variable. 1020 if (emission.IsByRef) 1021 emitByrefStructureInit(emission); 1022 1023 if (isTrivialInitializer(Init)) 1024 return; 1025 1026 CharUnits alignment = emission.Alignment; 1027 1028 // Check whether this is a byref variable that's potentially 1029 // captured and moved by its own initializer. If so, we'll need to 1030 // emit the initializer first, then copy into the variable. 1031 bool capturedByInit = emission.IsByRef && isCapturedBy(D, Init); 1032 1033 llvm::Value *Loc = 1034 capturedByInit ? emission.Address : emission.getObjectAddress(*this); 1035 1036 llvm::Constant *constant = 0; 1037 if (emission.IsConstantAggregate) { 1038 assert(!capturedByInit && "constant init contains a capturing block?"); 1039 constant = CGM.EmitConstantInit(D, this); 1040 } 1041 1042 if (!constant) { 1043 LValue lv = MakeAddrLValue(Loc, type, alignment); 1044 lv.setNonGC(true); 1045 return EmitExprAsInit(Init, &D, lv, capturedByInit); 1046 } 1047 1048 // If this is a simple aggregate initialization, we can optimize it 1049 // in various ways. 1050 bool isVolatile = type.isVolatileQualified(); 1051 1052 llvm::Value *SizeVal = 1053 llvm::ConstantInt::get(IntPtrTy, 1054 getContext().getTypeSizeInChars(type).getQuantity()); 1055 1056 llvm::Type *BP = Int8PtrTy; 1057 if (Loc->getType() != BP) 1058 Loc = Builder.CreateBitCast(Loc, BP); 1059 1060 // If the initializer is all or mostly zeros, codegen with memset then do 1061 // a few stores afterward. 1062 if (shouldUseMemSetPlusStoresToInitialize(constant, 1063 CGM.getTargetData().getTypeAllocSize(constant->getType()))) { 1064 Builder.CreateMemSet(Loc, llvm::ConstantInt::get(Int8Ty, 0), SizeVal, 1065 alignment.getQuantity(), isVolatile); 1066 // Zero and undef don't require a stores. 1067 if (!constant->isNullValue() && !isa<llvm::UndefValue>(constant)) { 1068 Loc = Builder.CreateBitCast(Loc, constant->getType()->getPointerTo()); 1069 emitStoresForInitAfterMemset(constant, Loc, isVolatile, Builder); 1070 } 1071 } else { 1072 // Otherwise, create a temporary global with the initializer then 1073 // memcpy from the global to the alloca. 1074 std::string Name = GetStaticDeclName(*this, D, "."); 1075 llvm::GlobalVariable *GV = 1076 new llvm::GlobalVariable(CGM.getModule(), constant->getType(), true, 1077 llvm::GlobalValue::PrivateLinkage, 1078 constant, Name); 1079 GV->setAlignment(alignment.getQuantity()); 1080 GV->setUnnamedAddr(true); 1081 1082 llvm::Value *SrcPtr = GV; 1083 if (SrcPtr->getType() != BP) 1084 SrcPtr = Builder.CreateBitCast(SrcPtr, BP); 1085 1086 Builder.CreateMemCpy(Loc, SrcPtr, SizeVal, alignment.getQuantity(), 1087 isVolatile); 1088 } 1089} 1090 1091/// Emit an expression as an initializer for a variable at the given 1092/// location. The expression is not necessarily the normal 1093/// initializer for the variable, and the address is not necessarily 1094/// its normal location. 1095/// 1096/// \param init the initializing expression 1097/// \param var the variable to act as if we're initializing 1098/// \param loc the address to initialize; its type is a pointer 1099/// to the LLVM mapping of the variable's type 1100/// \param alignment the alignment of the address 1101/// \param capturedByInit true if the variable is a __block variable 1102/// whose address is potentially changed by the initializer 1103void CodeGenFunction::EmitExprAsInit(const Expr *init, 1104 const ValueDecl *D, 1105 LValue lvalue, 1106 bool capturedByInit) { 1107 QualType type = D->getType(); 1108 1109 if (type->isReferenceType()) { 1110 RValue rvalue = EmitReferenceBindingToExpr(init, D); 1111 if (capturedByInit) 1112 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D)); 1113 EmitStoreThroughLValue(rvalue, lvalue, true); 1114 } else if (!hasAggregateLLVMType(type)) { 1115 EmitScalarInit(init, D, lvalue, capturedByInit); 1116 } else if (type->isAnyComplexType()) { 1117 ComplexPairTy complex = EmitComplexExpr(init); 1118 if (capturedByInit) 1119 drillIntoBlockVariable(*this, lvalue, cast<VarDecl>(D)); 1120 StoreComplexToAddr(complex, lvalue.getAddress(), lvalue.isVolatile()); 1121 } else { 1122 // TODO: how can we delay here if D is captured by its initializer? 1123 EmitAggExpr(init, AggValueSlot::forLValue(lvalue, 1124 AggValueSlot::IsDestructed, 1125 AggValueSlot::DoesNotNeedGCBarriers, 1126 AggValueSlot::IsNotAliased)); 1127 MaybeEmitStdInitializerListCleanup(lvalue.getAddress(), init); 1128 } 1129} 1130 1131/// Enter a destroy cleanup for the given local variable. 1132void CodeGenFunction::emitAutoVarTypeCleanup( 1133 const CodeGenFunction::AutoVarEmission &emission, 1134 QualType::DestructionKind dtorKind) { 1135 assert(dtorKind != QualType::DK_none); 1136 1137 // Note that for __block variables, we want to destroy the 1138 // original stack object, not the possibly forwarded object. 1139 llvm::Value *addr = emission.getObjectAddress(*this); 1140 1141 const VarDecl *var = emission.Variable; 1142 QualType type = var->getType(); 1143 1144 CleanupKind cleanupKind = NormalAndEHCleanup; 1145 CodeGenFunction::Destroyer *destroyer = 0; 1146 1147 switch (dtorKind) { 1148 case QualType::DK_none: 1149 llvm_unreachable("no cleanup for trivially-destructible variable"); 1150 1151 case QualType::DK_cxx_destructor: 1152 // If there's an NRVO flag on the emission, we need a different 1153 // cleanup. 1154 if (emission.NRVOFlag) { 1155 assert(!type->isArrayType()); 1156 CXXDestructorDecl *dtor = type->getAsCXXRecordDecl()->getDestructor(); 1157 EHStack.pushCleanup<DestroyNRVOVariable>(cleanupKind, addr, dtor, 1158 emission.NRVOFlag); 1159 return; 1160 } 1161 break; 1162 1163 case QualType::DK_objc_strong_lifetime: 1164 // Suppress cleanups for pseudo-strong variables. 1165 if (var->isARCPseudoStrong()) return; 1166 1167 // Otherwise, consider whether to use an EH cleanup or not. 1168 cleanupKind = getARCCleanupKind(); 1169 1170 // Use the imprecise destroyer by default. 1171 if (!var->hasAttr<ObjCPreciseLifetimeAttr>()) 1172 destroyer = CodeGenFunction::destroyARCStrongImprecise; 1173 break; 1174 1175 case QualType::DK_objc_weak_lifetime: 1176 break; 1177 } 1178 1179 // If we haven't chosen a more specific destroyer, use the default. 1180 if (!destroyer) destroyer = getDestroyer(dtorKind); 1181 1182 // Use an EH cleanup in array destructors iff the destructor itself 1183 // is being pushed as an EH cleanup. 1184 bool useEHCleanup = (cleanupKind & EHCleanup); 1185 EHStack.pushCleanup<DestroyObject>(cleanupKind, addr, type, destroyer, 1186 useEHCleanup); 1187} 1188 1189void CodeGenFunction::EmitAutoVarCleanups(const AutoVarEmission &emission) { 1190 assert(emission.Variable && "emission was not valid!"); 1191 1192 // If this was emitted as a global constant, we're done. 1193 if (emission.wasEmittedAsGlobal()) return; 1194 1195 // If we don't have an insertion point, we're done. Sema prevents 1196 // us from jumping into any of these scopes anyway. 1197 if (!HaveInsertPoint()) return; 1198 1199 const VarDecl &D = *emission.Variable; 1200 1201 // Check the type for a cleanup. 1202 if (QualType::DestructionKind dtorKind = D.getType().isDestructedType()) 1203 emitAutoVarTypeCleanup(emission, dtorKind); 1204 1205 // In GC mode, honor objc_precise_lifetime. 1206 if (getLangOpts().getGC() != LangOptions::NonGC && 1207 D.hasAttr<ObjCPreciseLifetimeAttr>()) { 1208 EHStack.pushCleanup<ExtendGCLifetime>(NormalCleanup, &D); 1209 } 1210 1211 // Handle the cleanup attribute. 1212 if (const CleanupAttr *CA = D.getAttr<CleanupAttr>()) { 1213 const FunctionDecl *FD = CA->getFunctionDecl(); 1214 1215 llvm::Constant *F = CGM.GetAddrOfFunction(FD); 1216 assert(F && "Could not find function!"); 1217 1218 const CGFunctionInfo &Info = CGM.getTypes().arrangeFunctionDeclaration(FD); 1219 EHStack.pushCleanup<CallCleanupFunction>(NormalAndEHCleanup, F, &Info, &D); 1220 } 1221 1222 // If this is a block variable, call _Block_object_destroy 1223 // (on the unforwarded address). 1224 if (emission.IsByRef) 1225 enterByrefCleanup(emission); 1226} 1227 1228CodeGenFunction::Destroyer * 1229CodeGenFunction::getDestroyer(QualType::DestructionKind kind) { 1230 switch (kind) { 1231 case QualType::DK_none: llvm_unreachable("no destroyer for trivial dtor"); 1232 case QualType::DK_cxx_destructor: 1233 return destroyCXXObject; 1234 case QualType::DK_objc_strong_lifetime: 1235 return destroyARCStrongPrecise; 1236 case QualType::DK_objc_weak_lifetime: 1237 return destroyARCWeak; 1238 } 1239 llvm_unreachable("Unknown DestructionKind"); 1240} 1241 1242/// pushDestroy - Push the standard destructor for the given type. 1243void CodeGenFunction::pushDestroy(QualType::DestructionKind dtorKind, 1244 llvm::Value *addr, QualType type) { 1245 assert(dtorKind && "cannot push destructor for trivial type"); 1246 1247 CleanupKind cleanupKind = getCleanupKind(dtorKind); 1248 pushDestroy(cleanupKind, addr, type, getDestroyer(dtorKind), 1249 cleanupKind & EHCleanup); 1250} 1251 1252void CodeGenFunction::pushDestroy(CleanupKind cleanupKind, llvm::Value *addr, 1253 QualType type, Destroyer *destroyer, 1254 bool useEHCleanupForArray) { 1255 pushFullExprCleanup<DestroyObject>(cleanupKind, addr, type, 1256 destroyer, useEHCleanupForArray); 1257} 1258 1259/// emitDestroy - Immediately perform the destruction of the given 1260/// object. 1261/// 1262/// \param addr - the address of the object; a type* 1263/// \param type - the type of the object; if an array type, all 1264/// objects are destroyed in reverse order 1265/// \param destroyer - the function to call to destroy individual 1266/// elements 1267/// \param useEHCleanupForArray - whether an EH cleanup should be 1268/// used when destroying array elements, in case one of the 1269/// destructions throws an exception 1270void CodeGenFunction::emitDestroy(llvm::Value *addr, QualType type, 1271 Destroyer *destroyer, 1272 bool useEHCleanupForArray) { 1273 const ArrayType *arrayType = getContext().getAsArrayType(type); 1274 if (!arrayType) 1275 return destroyer(*this, addr, type); 1276 1277 llvm::Value *begin = addr; 1278 llvm::Value *length = emitArrayLength(arrayType, type, begin); 1279 1280 // Normally we have to check whether the array is zero-length. 1281 bool checkZeroLength = true; 1282 1283 // But if the array length is constant, we can suppress that. 1284 if (llvm::ConstantInt *constLength = dyn_cast<llvm::ConstantInt>(length)) { 1285 // ...and if it's constant zero, we can just skip the entire thing. 1286 if (constLength->isZero()) return; 1287 checkZeroLength = false; 1288 } 1289 1290 llvm::Value *end = Builder.CreateInBoundsGEP(begin, length); 1291 emitArrayDestroy(begin, end, type, destroyer, 1292 checkZeroLength, useEHCleanupForArray); 1293} 1294 1295/// emitArrayDestroy - Destroys all the elements of the given array, 1296/// beginning from last to first. The array cannot be zero-length. 1297/// 1298/// \param begin - a type* denoting the first element of the array 1299/// \param end - a type* denoting one past the end of the array 1300/// \param type - the element type of the array 1301/// \param destroyer - the function to call to destroy elements 1302/// \param useEHCleanup - whether to push an EH cleanup to destroy 1303/// the remaining elements in case the destruction of a single 1304/// element throws 1305void CodeGenFunction::emitArrayDestroy(llvm::Value *begin, 1306 llvm::Value *end, 1307 QualType type, 1308 Destroyer *destroyer, 1309 bool checkZeroLength, 1310 bool useEHCleanup) { 1311 assert(!type->isArrayType()); 1312 1313 // The basic structure here is a do-while loop, because we don't 1314 // need to check for the zero-element case. 1315 llvm::BasicBlock *bodyBB = createBasicBlock("arraydestroy.body"); 1316 llvm::BasicBlock *doneBB = createBasicBlock("arraydestroy.done"); 1317 1318 if (checkZeroLength) { 1319 llvm::Value *isEmpty = Builder.CreateICmpEQ(begin, end, 1320 "arraydestroy.isempty"); 1321 Builder.CreateCondBr(isEmpty, doneBB, bodyBB); 1322 } 1323 1324 // Enter the loop body, making that address the current address. 1325 llvm::BasicBlock *entryBB = Builder.GetInsertBlock(); 1326 EmitBlock(bodyBB); 1327 llvm::PHINode *elementPast = 1328 Builder.CreatePHI(begin->getType(), 2, "arraydestroy.elementPast"); 1329 elementPast->addIncoming(end, entryBB); 1330 1331 // Shift the address back by one element. 1332 llvm::Value *negativeOne = llvm::ConstantInt::get(SizeTy, -1, true); 1333 llvm::Value *element = Builder.CreateInBoundsGEP(elementPast, negativeOne, 1334 "arraydestroy.element"); 1335 1336 if (useEHCleanup) 1337 pushRegularPartialArrayCleanup(begin, element, type, destroyer); 1338 1339 // Perform the actual destruction there. 1340 destroyer(*this, element, type); 1341 1342 if (useEHCleanup) 1343 PopCleanupBlock(); 1344 1345 // Check whether we've reached the end. 1346 llvm::Value *done = Builder.CreateICmpEQ(element, begin, "arraydestroy.done"); 1347 Builder.CreateCondBr(done, doneBB, bodyBB); 1348 elementPast->addIncoming(element, Builder.GetInsertBlock()); 1349 1350 // Done. 1351 EmitBlock(doneBB); 1352} 1353 1354/// Perform partial array destruction as if in an EH cleanup. Unlike 1355/// emitArrayDestroy, the element type here may still be an array type. 1356static void emitPartialArrayDestroy(CodeGenFunction &CGF, 1357 llvm::Value *begin, llvm::Value *end, 1358 QualType type, 1359 CodeGenFunction::Destroyer *destroyer) { 1360 // If the element type is itself an array, drill down. 1361 unsigned arrayDepth = 0; 1362 while (const ArrayType *arrayType = CGF.getContext().getAsArrayType(type)) { 1363 // VLAs don't require a GEP index to walk into. 1364 if (!isa<VariableArrayType>(arrayType)) 1365 arrayDepth++; 1366 type = arrayType->getElementType(); 1367 } 1368 1369 if (arrayDepth) { 1370 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, arrayDepth+1); 1371 1372 SmallVector<llvm::Value*,4> gepIndices(arrayDepth, zero); 1373 begin = CGF.Builder.CreateInBoundsGEP(begin, gepIndices, "pad.arraybegin"); 1374 end = CGF.Builder.CreateInBoundsGEP(end, gepIndices, "pad.arrayend"); 1375 } 1376 1377 // Destroy the array. We don't ever need an EH cleanup because we 1378 // assume that we're in an EH cleanup ourselves, so a throwing 1379 // destructor causes an immediate terminate. 1380 CGF.emitArrayDestroy(begin, end, type, destroyer, 1381 /*checkZeroLength*/ true, /*useEHCleanup*/ false); 1382} 1383 1384namespace { 1385 /// RegularPartialArrayDestroy - a cleanup which performs a partial 1386 /// array destroy where the end pointer is regularly determined and 1387 /// does not need to be loaded from a local. 1388 class RegularPartialArrayDestroy : public EHScopeStack::Cleanup { 1389 llvm::Value *ArrayBegin; 1390 llvm::Value *ArrayEnd; 1391 QualType ElementType; 1392 CodeGenFunction::Destroyer *Destroyer; 1393 public: 1394 RegularPartialArrayDestroy(llvm::Value *arrayBegin, llvm::Value *arrayEnd, 1395 QualType elementType, 1396 CodeGenFunction::Destroyer *destroyer) 1397 : ArrayBegin(arrayBegin), ArrayEnd(arrayEnd), 1398 ElementType(elementType), Destroyer(destroyer) {} 1399 1400 void Emit(CodeGenFunction &CGF, Flags flags) { 1401 emitPartialArrayDestroy(CGF, ArrayBegin, ArrayEnd, 1402 ElementType, Destroyer); 1403 } 1404 }; 1405 1406 /// IrregularPartialArrayDestroy - a cleanup which performs a 1407 /// partial array destroy where the end pointer is irregularly 1408 /// determined and must be loaded from a local. 1409 class IrregularPartialArrayDestroy : public EHScopeStack::Cleanup { 1410 llvm::Value *ArrayBegin; 1411 llvm::Value *ArrayEndPointer; 1412 QualType ElementType; 1413 CodeGenFunction::Destroyer *Destroyer; 1414 public: 1415 IrregularPartialArrayDestroy(llvm::Value *arrayBegin, 1416 llvm::Value *arrayEndPointer, 1417 QualType elementType, 1418 CodeGenFunction::Destroyer *destroyer) 1419 : ArrayBegin(arrayBegin), ArrayEndPointer(arrayEndPointer), 1420 ElementType(elementType), Destroyer(destroyer) {} 1421 1422 void Emit(CodeGenFunction &CGF, Flags flags) { 1423 llvm::Value *arrayEnd = CGF.Builder.CreateLoad(ArrayEndPointer); 1424 emitPartialArrayDestroy(CGF, ArrayBegin, arrayEnd, 1425 ElementType, Destroyer); 1426 } 1427 }; 1428} 1429 1430/// pushIrregularPartialArrayCleanup - Push an EH cleanup to destroy 1431/// already-constructed elements of the given array. The cleanup 1432/// may be popped with DeactivateCleanupBlock or PopCleanupBlock. 1433/// 1434/// \param elementType - the immediate element type of the array; 1435/// possibly still an array type 1436/// \param array - a value of type elementType* 1437/// \param destructionKind - the kind of destruction required 1438/// \param initializedElementCount - a value of type size_t* holding 1439/// the number of successfully-constructed elements 1440void CodeGenFunction::pushIrregularPartialArrayCleanup(llvm::Value *arrayBegin, 1441 llvm::Value *arrayEndPointer, 1442 QualType elementType, 1443 Destroyer *destroyer) { 1444 pushFullExprCleanup<IrregularPartialArrayDestroy>(EHCleanup, 1445 arrayBegin, arrayEndPointer, 1446 elementType, destroyer); 1447} 1448 1449/// pushRegularPartialArrayCleanup - Push an EH cleanup to destroy 1450/// already-constructed elements of the given array. The cleanup 1451/// may be popped with DeactivateCleanupBlock or PopCleanupBlock. 1452/// 1453/// \param elementType - the immediate element type of the array; 1454/// possibly still an array type 1455/// \param array - a value of type elementType* 1456/// \param destructionKind - the kind of destruction required 1457/// \param initializedElementCount - a value of type size_t* holding 1458/// the number of successfully-constructed elements 1459void CodeGenFunction::pushRegularPartialArrayCleanup(llvm::Value *arrayBegin, 1460 llvm::Value *arrayEnd, 1461 QualType elementType, 1462 Destroyer *destroyer) { 1463 pushFullExprCleanup<RegularPartialArrayDestroy>(EHCleanup, 1464 arrayBegin, arrayEnd, 1465 elementType, destroyer); 1466} 1467 1468namespace { 1469 /// A cleanup to perform a release of an object at the end of a 1470 /// function. This is used to balance out the incoming +1 of a 1471 /// ns_consumed argument when we can't reasonably do that just by 1472 /// not doing the initial retain for a __block argument. 1473 struct ConsumeARCParameter : EHScopeStack::Cleanup { 1474 ConsumeARCParameter(llvm::Value *param) : Param(param) {} 1475 1476 llvm::Value *Param; 1477 1478 void Emit(CodeGenFunction &CGF, Flags flags) { 1479 CGF.EmitARCRelease(Param, /*precise*/ false); 1480 } 1481 }; 1482} 1483 1484/// Emit an alloca (or GlobalValue depending on target) 1485/// for the specified parameter and set up LocalDeclMap. 1486void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg, 1487 unsigned ArgNo) { 1488 // FIXME: Why isn't ImplicitParamDecl a ParmVarDecl? 1489 assert((isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)) && 1490 "Invalid argument to EmitParmDecl"); 1491 1492 Arg->setName(D.getName()); 1493 1494 // Use better IR generation for certain implicit parameters. 1495 if (isa<ImplicitParamDecl>(D)) { 1496 // The only implicit argument a block has is its literal. 1497 if (BlockInfo) { 1498 LocalDeclMap[&D] = Arg; 1499 1500 if (CGDebugInfo *DI = getDebugInfo()) { 1501 if (CGM.getCodeGenOpts().DebugInfo >= 1502 CodeGenOptions::LimitedDebugInfo) { 1503 DI->setLocation(D.getLocation()); 1504 DI->EmitDeclareOfBlockLiteralArgVariable(*BlockInfo, Arg, Builder); 1505 } 1506 } 1507 1508 return; 1509 } 1510 } 1511 1512 QualType Ty = D.getType(); 1513 1514 llvm::Value *DeclPtr; 1515 // If this is an aggregate or variable sized value, reuse the input pointer. 1516 if (!Ty->isConstantSizeType() || 1517 CodeGenFunction::hasAggregateLLVMType(Ty)) { 1518 DeclPtr = Arg; 1519 } else { 1520 // Otherwise, create a temporary to hold the value. 1521 llvm::AllocaInst *Alloc = CreateTempAlloca(ConvertTypeForMem(Ty), 1522 D.getName() + ".addr"); 1523 Alloc->setAlignment(getContext().getDeclAlign(&D).getQuantity()); 1524 DeclPtr = Alloc; 1525 1526 bool doStore = true; 1527 1528 Qualifiers qs = Ty.getQualifiers(); 1529 1530 if (Qualifiers::ObjCLifetime lt = qs.getObjCLifetime()) { 1531 // We honor __attribute__((ns_consumed)) for types with lifetime. 1532 // For __strong, it's handled by just skipping the initial retain; 1533 // otherwise we have to balance out the initial +1 with an extra 1534 // cleanup to do the release at the end of the function. 1535 bool isConsumed = D.hasAttr<NSConsumedAttr>(); 1536 1537 // 'self' is always formally __strong, but if this is not an 1538 // init method then we don't want to retain it. 1539 if (D.isARCPseudoStrong()) { 1540 const ObjCMethodDecl *method = cast<ObjCMethodDecl>(CurCodeDecl); 1541 assert(&D == method->getSelfDecl()); 1542 assert(lt == Qualifiers::OCL_Strong); 1543 assert(qs.hasConst()); 1544 assert(method->getMethodFamily() != OMF_init); 1545 (void) method; 1546 lt = Qualifiers::OCL_ExplicitNone; 1547 } 1548 1549 if (lt == Qualifiers::OCL_Strong) { 1550 if (!isConsumed) 1551 // Don't use objc_retainBlock for block pointers, because we 1552 // don't want to Block_copy something just because we got it 1553 // as a parameter. 1554 Arg = EmitARCRetainNonBlock(Arg); 1555 } else { 1556 // Push the cleanup for a consumed parameter. 1557 if (isConsumed) 1558 EHStack.pushCleanup<ConsumeARCParameter>(getARCCleanupKind(), Arg); 1559 1560 if (lt == Qualifiers::OCL_Weak) { 1561 EmitARCInitWeak(DeclPtr, Arg); 1562 doStore = false; // The weak init is a store, no need to do two. 1563 } 1564 } 1565 1566 // Enter the cleanup scope. 1567 EmitAutoVarWithLifetime(*this, D, DeclPtr, lt); 1568 } 1569 1570 // Store the initial value into the alloca. 1571 if (doStore) { 1572 LValue lv = MakeAddrLValue(DeclPtr, Ty, 1573 getContext().getDeclAlign(&D)); 1574 EmitStoreOfScalar(Arg, lv, /* isInitialization */ true); 1575 } 1576 } 1577 1578 llvm::Value *&DMEntry = LocalDeclMap[&D]; 1579 assert(DMEntry == 0 && "Decl already exists in localdeclmap!"); 1580 DMEntry = DeclPtr; 1581 1582 // Emit debug info for param declaration. 1583 if (CGDebugInfo *DI = getDebugInfo()) { 1584 if (CGM.getCodeGenOpts().DebugInfo >= CodeGenOptions::LimitedDebugInfo) { 1585 DI->EmitDeclareOfArgVariable(&D, DeclPtr, ArgNo, Builder); 1586 } 1587 } 1588 1589 if (D.hasAttr<AnnotateAttr>()) 1590 EmitVarAnnotations(&D, DeclPtr); 1591} 1592