CGExprAgg.cpp revision 208600
1//===--- CGExprAgg.cpp - Emit LLVM Code from Aggregate Expressions --------===// 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 Aggregate Expr nodes as LLVM code. 11// 12//===----------------------------------------------------------------------===// 13 14#include "CodeGenFunction.h" 15#include "CodeGenModule.h" 16#include "CGObjCRuntime.h" 17#include "clang/AST/ASTContext.h" 18#include "clang/AST/DeclCXX.h" 19#include "clang/AST/StmtVisitor.h" 20#include "llvm/Constants.h" 21#include "llvm/Function.h" 22#include "llvm/GlobalVariable.h" 23#include "llvm/Intrinsics.h" 24using namespace clang; 25using namespace CodeGen; 26 27//===----------------------------------------------------------------------===// 28// Aggregate Expression Emitter 29//===----------------------------------------------------------------------===// 30 31namespace { 32class AggExprEmitter : public StmtVisitor<AggExprEmitter> { 33 CodeGenFunction &CGF; 34 CGBuilderTy &Builder; 35 llvm::Value *DestPtr; 36 bool VolatileDest; 37 bool IgnoreResult; 38 bool IsInitializer; 39 bool RequiresGCollection; 40 41 ReturnValueSlot getReturnValueSlot() const { 42 // If the destination slot requires garbage collection, we can't 43 // use the real return value slot, because we have to use the GC 44 // API. 45 if (RequiresGCollection) return ReturnValueSlot(); 46 47 return ReturnValueSlot(DestPtr, VolatileDest); 48 } 49 50public: 51 AggExprEmitter(CodeGenFunction &cgf, llvm::Value *destPtr, bool v, 52 bool ignore, bool isinit, bool requiresGCollection) 53 : CGF(cgf), Builder(CGF.Builder), 54 DestPtr(destPtr), VolatileDest(v), IgnoreResult(ignore), 55 IsInitializer(isinit), RequiresGCollection(requiresGCollection) { 56 } 57 58 //===--------------------------------------------------------------------===// 59 // Utilities 60 //===--------------------------------------------------------------------===// 61 62 /// EmitAggLoadOfLValue - Given an expression with aggregate type that 63 /// represents a value lvalue, this method emits the address of the lvalue, 64 /// then loads the result into DestPtr. 65 void EmitAggLoadOfLValue(const Expr *E); 66 67 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. 68 void EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore = false); 69 void EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore = false); 70 71 void EmitGCMove(const Expr *E, RValue Src); 72 73 bool TypeRequiresGCollection(QualType T); 74 75 //===--------------------------------------------------------------------===// 76 // Visitor Methods 77 //===--------------------------------------------------------------------===// 78 79 void VisitStmt(Stmt *S) { 80 CGF.ErrorUnsupported(S, "aggregate expression"); 81 } 82 void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); } 83 void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); } 84 85 // l-values. 86 void VisitDeclRefExpr(DeclRefExpr *DRE) { EmitAggLoadOfLValue(DRE); } 87 void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); } 88 void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); } 89 void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); } 90 void VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { 91 EmitAggLoadOfLValue(E); 92 } 93 void VisitArraySubscriptExpr(ArraySubscriptExpr *E) { 94 EmitAggLoadOfLValue(E); 95 } 96 void VisitBlockDeclRefExpr(const BlockDeclRefExpr *E) { 97 EmitAggLoadOfLValue(E); 98 } 99 void VisitPredefinedExpr(const PredefinedExpr *E) { 100 EmitAggLoadOfLValue(E); 101 } 102 103 // Operators. 104 void VisitCastExpr(CastExpr *E); 105 void VisitCallExpr(const CallExpr *E); 106 void VisitStmtExpr(const StmtExpr *E); 107 void VisitBinaryOperator(const BinaryOperator *BO); 108 void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO); 109 void VisitBinAssign(const BinaryOperator *E); 110 void VisitBinComma(const BinaryOperator *E); 111 void VisitUnaryAddrOf(const UnaryOperator *E); 112 113 void VisitObjCMessageExpr(ObjCMessageExpr *E); 114 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) { 115 EmitAggLoadOfLValue(E); 116 } 117 void VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E); 118 void VisitObjCImplicitSetterGetterRefExpr(ObjCImplicitSetterGetterRefExpr *E); 119 120 void VisitConditionalOperator(const ConditionalOperator *CO); 121 void VisitChooseExpr(const ChooseExpr *CE); 122 void VisitInitListExpr(InitListExpr *E); 123 void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E); 124 void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) { 125 Visit(DAE->getExpr()); 126 } 127 void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E); 128 void VisitCXXConstructExpr(const CXXConstructExpr *E); 129 void VisitCXXExprWithTemporaries(CXXExprWithTemporaries *E); 130 void VisitCXXZeroInitValueExpr(CXXZeroInitValueExpr *E); 131 void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); } 132 133 void VisitVAArgExpr(VAArgExpr *E); 134 135 void EmitInitializationToLValue(Expr *E, LValue Address, QualType T); 136 void EmitNullInitializationToLValue(LValue Address, QualType T); 137 // case Expr::ChooseExprClass: 138 void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); } 139}; 140} // end anonymous namespace. 141 142//===----------------------------------------------------------------------===// 143// Utilities 144//===----------------------------------------------------------------------===// 145 146/// EmitAggLoadOfLValue - Given an expression with aggregate type that 147/// represents a value lvalue, this method emits the address of the lvalue, 148/// then loads the result into DestPtr. 149void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) { 150 LValue LV = CGF.EmitLValue(E); 151 EmitFinalDestCopy(E, LV); 152} 153 154/// \brief True if the given aggregate type requires special GC API calls. 155bool AggExprEmitter::TypeRequiresGCollection(QualType T) { 156 // Only record types have members that might require garbage collection. 157 const RecordType *RecordTy = T->getAs<RecordType>(); 158 if (!RecordTy) return false; 159 160 // Don't mess with non-trivial C++ types. 161 RecordDecl *Record = RecordTy->getDecl(); 162 if (isa<CXXRecordDecl>(Record) && 163 (!cast<CXXRecordDecl>(Record)->hasTrivialCopyConstructor() || 164 !cast<CXXRecordDecl>(Record)->hasTrivialDestructor())) 165 return false; 166 167 // Check whether the type has an object member. 168 return Record->hasObjectMember(); 169} 170 171/// \brief Perform the final move to DestPtr if RequiresGCollection is set. 172/// 173/// The idea is that you do something like this: 174/// RValue Result = EmitSomething(..., getReturnValueSlot()); 175/// EmitGCMove(E, Result); 176/// If GC doesn't interfere, this will cause the result to be emitted 177/// directly into the return value slot. If GC does interfere, a final 178/// move will be performed. 179void AggExprEmitter::EmitGCMove(const Expr *E, RValue Src) { 180 if (!RequiresGCollection) return; 181 182 CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF, DestPtr, 183 Src.getAggregateAddr(), 184 E->getType()); 185} 186 187/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. 188void AggExprEmitter::EmitFinalDestCopy(const Expr *E, RValue Src, bool Ignore) { 189 assert(Src.isAggregate() && "value must be aggregate value!"); 190 191 // If the result is ignored, don't copy from the value. 192 if (DestPtr == 0) { 193 if (!Src.isVolatileQualified() || (IgnoreResult && Ignore)) 194 return; 195 // If the source is volatile, we must read from it; to do that, we need 196 // some place to put it. 197 DestPtr = CGF.CreateMemTemp(E->getType(), "agg.tmp"); 198 } 199 200 if (RequiresGCollection) { 201 CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF, 202 DestPtr, Src.getAggregateAddr(), 203 E->getType()); 204 return; 205 } 206 // If the result of the assignment is used, copy the LHS there also. 207 // FIXME: Pass VolatileDest as well. I think we also need to merge volatile 208 // from the source as well, as we can't eliminate it if either operand 209 // is volatile, unless copy has volatile for both source and destination.. 210 CGF.EmitAggregateCopy(DestPtr, Src.getAggregateAddr(), E->getType(), 211 VolatileDest|Src.isVolatileQualified()); 212} 213 214/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. 215void AggExprEmitter::EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore) { 216 assert(Src.isSimple() && "Can't have aggregate bitfield, vector, etc"); 217 218 EmitFinalDestCopy(E, RValue::getAggregate(Src.getAddress(), 219 Src.isVolatileQualified()), 220 Ignore); 221} 222 223//===----------------------------------------------------------------------===// 224// Visitor Methods 225//===----------------------------------------------------------------------===// 226 227void AggExprEmitter::VisitCastExpr(CastExpr *E) { 228 if (!DestPtr && E->getCastKind() != CastExpr::CK_Dynamic) { 229 Visit(E->getSubExpr()); 230 return; 231 } 232 233 switch (E->getCastKind()) { 234 default: assert(0 && "Unhandled cast kind!"); 235 236 case CastExpr::CK_Dynamic: { 237 assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?"); 238 LValue LV = CGF.EmitCheckedLValue(E->getSubExpr()); 239 // FIXME: Do we also need to handle property references here? 240 if (LV.isSimple()) 241 CGF.EmitDynamicCast(LV.getAddress(), cast<CXXDynamicCastExpr>(E)); 242 else 243 CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast"); 244 245 if (DestPtr) 246 CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination"); 247 break; 248 } 249 250 case CastExpr::CK_ToUnion: { 251 // GCC union extension 252 QualType PtrTy = 253 CGF.getContext().getPointerType(E->getSubExpr()->getType()); 254 llvm::Value *CastPtr = Builder.CreateBitCast(DestPtr, 255 CGF.ConvertType(PtrTy)); 256 EmitInitializationToLValue(E->getSubExpr(), 257 LValue::MakeAddr(CastPtr, Qualifiers()), 258 E->getSubExpr()->getType()); 259 break; 260 } 261 262 case CastExpr::CK_DerivedToBase: 263 case CastExpr::CK_BaseToDerived: 264 case CastExpr::CK_UncheckedDerivedToBase: { 265 assert(0 && "cannot perform hierarchy conversion in EmitAggExpr: " 266 "should have been unpacked before we got here"); 267 break; 268 } 269 270 // FIXME: Remove the CK_Unknown check here. 271 case CastExpr::CK_Unknown: 272 case CastExpr::CK_NoOp: 273 case CastExpr::CK_UserDefinedConversion: 274 case CastExpr::CK_ConstructorConversion: 275 assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(), 276 E->getType()) && 277 "Implicit cast types must be compatible"); 278 Visit(E->getSubExpr()); 279 break; 280 281 case CastExpr::CK_NullToMemberPointer: { 282 // If the subexpression's type is the C++0x nullptr_t, emit the 283 // subexpression, which may have side effects. 284 if (E->getSubExpr()->getType()->isNullPtrType()) 285 Visit(E->getSubExpr()); 286 287 const llvm::Type *PtrDiffTy = 288 CGF.ConvertType(CGF.getContext().getPointerDiffType()); 289 290 llvm::Value *NullValue = llvm::Constant::getNullValue(PtrDiffTy); 291 llvm::Value *Ptr = Builder.CreateStructGEP(DestPtr, 0, "ptr"); 292 Builder.CreateStore(NullValue, Ptr, VolatileDest); 293 294 llvm::Value *Adj = Builder.CreateStructGEP(DestPtr, 1, "adj"); 295 Builder.CreateStore(NullValue, Adj, VolatileDest); 296 297 break; 298 } 299 300 case CastExpr::CK_BitCast: { 301 // This must be a member function pointer cast. 302 Visit(E->getSubExpr()); 303 break; 304 } 305 306 case CastExpr::CK_DerivedToBaseMemberPointer: 307 case CastExpr::CK_BaseToDerivedMemberPointer: { 308 QualType SrcType = E->getSubExpr()->getType(); 309 310 llvm::Value *Src = CGF.CreateMemTemp(SrcType, "tmp"); 311 CGF.EmitAggExpr(E->getSubExpr(), Src, SrcType.isVolatileQualified()); 312 313 llvm::Value *SrcPtr = Builder.CreateStructGEP(Src, 0, "src.ptr"); 314 SrcPtr = Builder.CreateLoad(SrcPtr); 315 316 llvm::Value *SrcAdj = Builder.CreateStructGEP(Src, 1, "src.adj"); 317 SrcAdj = Builder.CreateLoad(SrcAdj); 318 319 llvm::Value *DstPtr = Builder.CreateStructGEP(DestPtr, 0, "dst.ptr"); 320 Builder.CreateStore(SrcPtr, DstPtr, VolatileDest); 321 322 llvm::Value *DstAdj = Builder.CreateStructGEP(DestPtr, 1, "dst.adj"); 323 324 // Now See if we need to update the adjustment. 325 const CXXRecordDecl *BaseDecl = 326 cast<CXXRecordDecl>(SrcType->getAs<MemberPointerType>()-> 327 getClass()->getAs<RecordType>()->getDecl()); 328 const CXXRecordDecl *DerivedDecl = 329 cast<CXXRecordDecl>(E->getType()->getAs<MemberPointerType>()-> 330 getClass()->getAs<RecordType>()->getDecl()); 331 if (E->getCastKind() == CastExpr::CK_DerivedToBaseMemberPointer) 332 std::swap(DerivedDecl, BaseDecl); 333 334 if (llvm::Constant *Adj = 335 CGF.CGM.GetNonVirtualBaseClassOffset(DerivedDecl, E->getBasePath())) { 336 if (E->getCastKind() == CastExpr::CK_DerivedToBaseMemberPointer) 337 SrcAdj = Builder.CreateSub(SrcAdj, Adj, "adj"); 338 else 339 SrcAdj = Builder.CreateAdd(SrcAdj, Adj, "adj"); 340 } 341 342 Builder.CreateStore(SrcAdj, DstAdj, VolatileDest); 343 break; 344 } 345 } 346} 347 348void AggExprEmitter::VisitCallExpr(const CallExpr *E) { 349 if (E->getCallReturnType()->isReferenceType()) { 350 EmitAggLoadOfLValue(E); 351 return; 352 } 353 354 RValue RV = CGF.EmitCallExpr(E, getReturnValueSlot()); 355 EmitGCMove(E, RV); 356} 357 358void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) { 359 RValue RV = CGF.EmitObjCMessageExpr(E, getReturnValueSlot()); 360 EmitGCMove(E, RV); 361} 362 363void AggExprEmitter::VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E) { 364 RValue RV = CGF.EmitObjCPropertyGet(E, getReturnValueSlot()); 365 EmitGCMove(E, RV); 366} 367 368void AggExprEmitter::VisitObjCImplicitSetterGetterRefExpr( 369 ObjCImplicitSetterGetterRefExpr *E) { 370 RValue RV = CGF.EmitObjCPropertyGet(E, getReturnValueSlot()); 371 EmitGCMove(E, RV); 372} 373 374void AggExprEmitter::VisitBinComma(const BinaryOperator *E) { 375 CGF.EmitAnyExpr(E->getLHS(), 0, false, true); 376 CGF.EmitAggExpr(E->getRHS(), DestPtr, VolatileDest, 377 /*IgnoreResult=*/false, IsInitializer); 378} 379 380void AggExprEmitter::VisitUnaryAddrOf(const UnaryOperator *E) { 381 // We have a member function pointer. 382 const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>(); 383 (void) MPT; 384 assert(MPT->getPointeeType()->isFunctionProtoType() && 385 "Unexpected member pointer type!"); 386 387 // The creation of member function pointers has no side effects; if 388 // there is no destination pointer, we have nothing to do. 389 if (!DestPtr) 390 return; 391 392 const DeclRefExpr *DRE = cast<DeclRefExpr>(E->getSubExpr()); 393 const CXXMethodDecl *MD = 394 cast<CXXMethodDecl>(DRE->getDecl())->getCanonicalDecl(); 395 396 const llvm::Type *PtrDiffTy = 397 CGF.ConvertType(CGF.getContext().getPointerDiffType()); 398 399 400 llvm::Value *DstPtr = Builder.CreateStructGEP(DestPtr, 0, "dst.ptr"); 401 llvm::Value *FuncPtr; 402 403 if (MD->isVirtual()) { 404 int64_t Index = CGF.CGM.getVTables().getMethodVTableIndex(MD); 405 406 // FIXME: We shouldn't use / 8 here. 407 uint64_t PointerWidthInBytes = 408 CGF.CGM.getContext().Target.getPointerWidth(0) / 8; 409 410 // Itanium C++ ABI 2.3: 411 // For a non-virtual function, this field is a simple function pointer. 412 // For a virtual function, it is 1 plus the virtual table offset 413 // (in bytes) of the function, represented as a ptrdiff_t. 414 FuncPtr = llvm::ConstantInt::get(PtrDiffTy, 415 (Index * PointerWidthInBytes) + 1); 416 } else { 417 const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>(); 418 const llvm::Type *Ty = 419 CGF.CGM.getTypes().GetFunctionType(CGF.CGM.getTypes().getFunctionInfo(MD), 420 FPT->isVariadic()); 421 llvm::Constant *Fn = CGF.CGM.GetAddrOfFunction(MD, Ty); 422 FuncPtr = llvm::ConstantExpr::getPtrToInt(Fn, PtrDiffTy); 423 } 424 Builder.CreateStore(FuncPtr, DstPtr, VolatileDest); 425 426 llvm::Value *AdjPtr = Builder.CreateStructGEP(DestPtr, 1, "dst.adj"); 427 428 // The adjustment will always be 0. 429 Builder.CreateStore(llvm::ConstantInt::get(PtrDiffTy, 0), AdjPtr, 430 VolatileDest); 431} 432 433void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) { 434 CGF.EmitCompoundStmt(*E->getSubStmt(), true, DestPtr, VolatileDest); 435} 436 437void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) { 438 if (E->getOpcode() == BinaryOperator::PtrMemD || 439 E->getOpcode() == BinaryOperator::PtrMemI) 440 VisitPointerToDataMemberBinaryOperator(E); 441 else 442 CGF.ErrorUnsupported(E, "aggregate binary expression"); 443} 444 445void AggExprEmitter::VisitPointerToDataMemberBinaryOperator( 446 const BinaryOperator *E) { 447 LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E); 448 EmitFinalDestCopy(E, LV); 449} 450 451void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) { 452 // For an assignment to work, the value on the right has 453 // to be compatible with the value on the left. 454 assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(), 455 E->getRHS()->getType()) 456 && "Invalid assignment"); 457 LValue LHS = CGF.EmitLValue(E->getLHS()); 458 459 // We have to special case property setters, otherwise we must have 460 // a simple lvalue (no aggregates inside vectors, bitfields). 461 if (LHS.isPropertyRef()) { 462 llvm::Value *AggLoc = DestPtr; 463 if (!AggLoc) 464 AggLoc = CGF.CreateMemTemp(E->getRHS()->getType()); 465 CGF.EmitAggExpr(E->getRHS(), AggLoc, VolatileDest); 466 CGF.EmitObjCPropertySet(LHS.getPropertyRefExpr(), 467 RValue::getAggregate(AggLoc, VolatileDest)); 468 } else if (LHS.isKVCRef()) { 469 llvm::Value *AggLoc = DestPtr; 470 if (!AggLoc) 471 AggLoc = CGF.CreateMemTemp(E->getRHS()->getType()); 472 CGF.EmitAggExpr(E->getRHS(), AggLoc, VolatileDest); 473 CGF.EmitObjCPropertySet(LHS.getKVCRefExpr(), 474 RValue::getAggregate(AggLoc, VolatileDest)); 475 } else { 476 bool RequiresGCollection = false; 477 if (CGF.getContext().getLangOptions().getGCMode()) 478 RequiresGCollection = TypeRequiresGCollection(E->getLHS()->getType()); 479 480 // Codegen the RHS so that it stores directly into the LHS. 481 CGF.EmitAggExpr(E->getRHS(), LHS.getAddress(), LHS.isVolatileQualified(), 482 false, false, RequiresGCollection); 483 EmitFinalDestCopy(E, LHS, true); 484 } 485} 486 487void AggExprEmitter::VisitConditionalOperator(const ConditionalOperator *E) { 488 if (!E->getLHS()) { 489 CGF.ErrorUnsupported(E, "conditional operator with missing LHS"); 490 return; 491 } 492 493 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true"); 494 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false"); 495 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end"); 496 497 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock); 498 499 CGF.BeginConditionalBranch(); 500 CGF.EmitBlock(LHSBlock); 501 502 // Handle the GNU extension for missing LHS. 503 assert(E->getLHS() && "Must have LHS for aggregate value"); 504 505 Visit(E->getLHS()); 506 CGF.EndConditionalBranch(); 507 CGF.EmitBranch(ContBlock); 508 509 CGF.BeginConditionalBranch(); 510 CGF.EmitBlock(RHSBlock); 511 512 Visit(E->getRHS()); 513 CGF.EndConditionalBranch(); 514 CGF.EmitBranch(ContBlock); 515 516 CGF.EmitBlock(ContBlock); 517} 518 519void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) { 520 Visit(CE->getChosenSubExpr(CGF.getContext())); 521} 522 523void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) { 524 llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr()); 525 llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType()); 526 527 if (!ArgPtr) { 528 CGF.ErrorUnsupported(VE, "aggregate va_arg expression"); 529 return; 530 } 531 532 EmitFinalDestCopy(VE, LValue::MakeAddr(ArgPtr, Qualifiers())); 533} 534 535void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) { 536 llvm::Value *Val = DestPtr; 537 538 if (!Val) { 539 // Create a temporary variable. 540 Val = CGF.CreateMemTemp(E->getType(), "tmp"); 541 542 // FIXME: volatile 543 CGF.EmitAggExpr(E->getSubExpr(), Val, false); 544 } else 545 Visit(E->getSubExpr()); 546 547 // Don't make this a live temporary if we're emitting an initializer expr. 548 if (!IsInitializer) 549 CGF.PushCXXTemporary(E->getTemporary(), Val); 550} 551 552void 553AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) { 554 llvm::Value *Val = DestPtr; 555 556 if (!Val) { 557 // Create a temporary variable. 558 Val = CGF.CreateMemTemp(E->getType(), "tmp"); 559 } 560 561 if (E->requiresZeroInitialization()) 562 EmitNullInitializationToLValue(LValue::MakeAddr(Val, 563 // FIXME: Qualifiers()? 564 E->getType().getQualifiers()), 565 E->getType()); 566 567 CGF.EmitCXXConstructExpr(Val, E); 568} 569 570void AggExprEmitter::VisitCXXExprWithTemporaries(CXXExprWithTemporaries *E) { 571 llvm::Value *Val = DestPtr; 572 573 CGF.EmitCXXExprWithTemporaries(E, Val, VolatileDest, IsInitializer); 574} 575 576void AggExprEmitter::VisitCXXZeroInitValueExpr(CXXZeroInitValueExpr *E) { 577 llvm::Value *Val = DestPtr; 578 579 if (!Val) { 580 // Create a temporary variable. 581 Val = CGF.CreateMemTemp(E->getType(), "tmp"); 582 } 583 LValue LV = LValue::MakeAddr(Val, Qualifiers()); 584 EmitNullInitializationToLValue(LV, E->getType()); 585} 586 587void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) { 588 llvm::Value *Val = DestPtr; 589 590 if (!Val) { 591 // Create a temporary variable. 592 Val = CGF.CreateMemTemp(E->getType(), "tmp"); 593 } 594 LValue LV = LValue::MakeAddr(Val, Qualifiers()); 595 EmitNullInitializationToLValue(LV, E->getType()); 596} 597 598void 599AggExprEmitter::EmitInitializationToLValue(Expr* E, LValue LV, QualType T) { 600 // FIXME: Ignore result? 601 // FIXME: Are initializers affected by volatile? 602 if (isa<ImplicitValueInitExpr>(E)) { 603 EmitNullInitializationToLValue(LV, T); 604 } else if (T->isReferenceType()) { 605 RValue RV = CGF.EmitReferenceBindingToExpr(E, /*IsInitializer=*/false); 606 CGF.EmitStoreThroughLValue(RV, LV, T); 607 } else if (T->isAnyComplexType()) { 608 CGF.EmitComplexExprIntoAddr(E, LV.getAddress(), false); 609 } else if (CGF.hasAggregateLLVMType(T)) { 610 CGF.EmitAnyExpr(E, LV.getAddress(), false); 611 } else { 612 CGF.EmitStoreThroughLValue(CGF.EmitAnyExpr(E), LV, T); 613 } 614} 615 616void AggExprEmitter::EmitNullInitializationToLValue(LValue LV, QualType T) { 617 if (!CGF.hasAggregateLLVMType(T)) { 618 // For non-aggregates, we can store zero 619 llvm::Value *Null = llvm::Constant::getNullValue(CGF.ConvertType(T)); 620 CGF.EmitStoreThroughLValue(RValue::get(Null), LV, T); 621 } else { 622 // There's a potential optimization opportunity in combining 623 // memsets; that would be easy for arrays, but relatively 624 // difficult for structures with the current code. 625 CGF.EmitNullInitialization(LV.getAddress(), T); 626 } 627} 628 629void AggExprEmitter::VisitInitListExpr(InitListExpr *E) { 630#if 0 631 // FIXME: Assess perf here? Figure out what cases are worth optimizing here 632 // (Length of globals? Chunks of zeroed-out space?). 633 // 634 // If we can, prefer a copy from a global; this is a lot less code for long 635 // globals, and it's easier for the current optimizers to analyze. 636 if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) { 637 llvm::GlobalVariable* GV = 638 new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true, 639 llvm::GlobalValue::InternalLinkage, C, ""); 640 EmitFinalDestCopy(E, LValue::MakeAddr(GV, Qualifiers())); 641 return; 642 } 643#endif 644 if (E->hadArrayRangeDesignator()) { 645 CGF.ErrorUnsupported(E, "GNU array range designator extension"); 646 } 647 648 // Handle initialization of an array. 649 if (E->getType()->isArrayType()) { 650 const llvm::PointerType *APType = 651 cast<llvm::PointerType>(DestPtr->getType()); 652 const llvm::ArrayType *AType = 653 cast<llvm::ArrayType>(APType->getElementType()); 654 655 uint64_t NumInitElements = E->getNumInits(); 656 657 if (E->getNumInits() > 0) { 658 QualType T1 = E->getType(); 659 QualType T2 = E->getInit(0)->getType(); 660 if (CGF.getContext().hasSameUnqualifiedType(T1, T2)) { 661 EmitAggLoadOfLValue(E->getInit(0)); 662 return; 663 } 664 } 665 666 uint64_t NumArrayElements = AType->getNumElements(); 667 QualType ElementType = CGF.getContext().getCanonicalType(E->getType()); 668 ElementType = CGF.getContext().getAsArrayType(ElementType)->getElementType(); 669 670 // FIXME: were we intentionally ignoring address spaces and GC attributes? 671 Qualifiers Quals = CGF.MakeQualifiers(ElementType); 672 673 for (uint64_t i = 0; i != NumArrayElements; ++i) { 674 llvm::Value *NextVal = Builder.CreateStructGEP(DestPtr, i, ".array"); 675 if (i < NumInitElements) 676 EmitInitializationToLValue(E->getInit(i), 677 LValue::MakeAddr(NextVal, Quals), 678 ElementType); 679 else 680 EmitNullInitializationToLValue(LValue::MakeAddr(NextVal, Quals), 681 ElementType); 682 } 683 return; 684 } 685 686 assert(E->getType()->isRecordType() && "Only support structs/unions here!"); 687 688 // Do struct initialization; this code just sets each individual member 689 // to the approprate value. This makes bitfield support automatic; 690 // the disadvantage is that the generated code is more difficult for 691 // the optimizer, especially with bitfields. 692 unsigned NumInitElements = E->getNumInits(); 693 RecordDecl *SD = E->getType()->getAs<RecordType>()->getDecl(); 694 unsigned CurInitVal = 0; 695 696 if (E->getType()->isUnionType()) { 697 // Only initialize one field of a union. The field itself is 698 // specified by the initializer list. 699 if (!E->getInitializedFieldInUnion()) { 700 // Empty union; we have nothing to do. 701 702#ifndef NDEBUG 703 // Make sure that it's really an empty and not a failure of 704 // semantic analysis. 705 for (RecordDecl::field_iterator Field = SD->field_begin(), 706 FieldEnd = SD->field_end(); 707 Field != FieldEnd; ++Field) 708 assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed"); 709#endif 710 return; 711 } 712 713 // FIXME: volatility 714 FieldDecl *Field = E->getInitializedFieldInUnion(); 715 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestPtr, Field, 0); 716 717 if (NumInitElements) { 718 // Store the initializer into the field 719 EmitInitializationToLValue(E->getInit(0), FieldLoc, Field->getType()); 720 } else { 721 // Default-initialize to null 722 EmitNullInitializationToLValue(FieldLoc, Field->getType()); 723 } 724 725 return; 726 } 727 728 // If we're initializing the whole aggregate, just do it in place. 729 // FIXME: This is a hack around an AST bug (PR6537). 730 if (NumInitElements == 1 && E->getType() == E->getInit(0)->getType()) { 731 EmitInitializationToLValue(E->getInit(0), 732 LValue::MakeAddr(DestPtr, Qualifiers()), 733 E->getType()); 734 return; 735 } 736 737 738 // Here we iterate over the fields; this makes it simpler to both 739 // default-initialize fields and skip over unnamed fields. 740 for (RecordDecl::field_iterator Field = SD->field_begin(), 741 FieldEnd = SD->field_end(); 742 Field != FieldEnd; ++Field) { 743 // We're done once we hit the flexible array member 744 if (Field->getType()->isIncompleteArrayType()) 745 break; 746 747 if (Field->isUnnamedBitfield()) 748 continue; 749 750 // FIXME: volatility 751 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestPtr, *Field, 0); 752 // We never generate write-barries for initialized fields. 753 LValue::SetObjCNonGC(FieldLoc, true); 754 if (CurInitVal < NumInitElements) { 755 // Store the initializer into the field. 756 EmitInitializationToLValue(E->getInit(CurInitVal++), FieldLoc, 757 Field->getType()); 758 } else { 759 // We're out of initalizers; default-initialize to null 760 EmitNullInitializationToLValue(FieldLoc, Field->getType()); 761 } 762 } 763} 764 765//===----------------------------------------------------------------------===// 766// Entry Points into this File 767//===----------------------------------------------------------------------===// 768 769/// EmitAggExpr - Emit the computation of the specified expression of aggregate 770/// type. The result is computed into DestPtr. Note that if DestPtr is null, 771/// the value of the aggregate expression is not needed. If VolatileDest is 772/// true, DestPtr cannot be 0. 773// 774// FIXME: Take Qualifiers object. 775void CodeGenFunction::EmitAggExpr(const Expr *E, llvm::Value *DestPtr, 776 bool VolatileDest, bool IgnoreResult, 777 bool IsInitializer, 778 bool RequiresGCollection) { 779 assert(E && hasAggregateLLVMType(E->getType()) && 780 "Invalid aggregate expression to emit"); 781 assert ((DestPtr != 0 || VolatileDest == false) 782 && "volatile aggregate can't be 0"); 783 784 AggExprEmitter(*this, DestPtr, VolatileDest, IgnoreResult, IsInitializer, 785 RequiresGCollection) 786 .Visit(const_cast<Expr*>(E)); 787} 788 789LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) { 790 assert(hasAggregateLLVMType(E->getType()) && "Invalid argument!"); 791 Qualifiers Q = MakeQualifiers(E->getType()); 792 llvm::Value *Temp = CreateMemTemp(E->getType()); 793 EmitAggExpr(E, Temp, Q.hasVolatile()); 794 return LValue::MakeAddr(Temp, Q); 795} 796 797void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr, 798 llvm::Value *SrcPtr, QualType Ty, 799 bool isVolatile) { 800 assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex"); 801 802 if (getContext().getLangOptions().CPlusPlus) { 803 if (const RecordType *RT = Ty->getAs<RecordType>()) { 804 CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl()); 805 assert((Record->hasTrivialCopyConstructor() || 806 Record->hasTrivialCopyAssignment()) && 807 "Trying to aggregate-copy a type without a trivial copy " 808 "constructor or assignment operator"); 809 // Ignore empty classes in C++. 810 if (Record->isEmpty()) 811 return; 812 } 813 } 814 815 // Aggregate assignment turns into llvm.memcpy. This is almost valid per 816 // C99 6.5.16.1p3, which states "If the value being stored in an object is 817 // read from another object that overlaps in anyway the storage of the first 818 // object, then the overlap shall be exact and the two objects shall have 819 // qualified or unqualified versions of a compatible type." 820 // 821 // memcpy is not defined if the source and destination pointers are exactly 822 // equal, but other compilers do this optimization, and almost every memcpy 823 // implementation handles this case safely. If there is a libc that does not 824 // safely handle this, we can add a target hook. 825 const llvm::Type *BP = llvm::Type::getInt8PtrTy(VMContext); 826 if (DestPtr->getType() != BP) 827 DestPtr = Builder.CreateBitCast(DestPtr, BP, "tmp"); 828 if (SrcPtr->getType() != BP) 829 SrcPtr = Builder.CreateBitCast(SrcPtr, BP, "tmp"); 830 831 // Get size and alignment info for this aggregate. 832 std::pair<uint64_t, unsigned> TypeInfo = getContext().getTypeInfo(Ty); 833 834 // FIXME: Handle variable sized types. 835 const llvm::Type *IntPtr = 836 llvm::IntegerType::get(VMContext, LLVMPointerWidth); 837 838 // FIXME: If we have a volatile struct, the optimizer can remove what might 839 // appear to be `extra' memory ops: 840 // 841 // volatile struct { int i; } a, b; 842 // 843 // int main() { 844 // a = b; 845 // a = b; 846 // } 847 // 848 // we need to use a different call here. We use isVolatile to indicate when 849 // either the source or the destination is volatile. 850 const llvm::Type *I1Ty = llvm::Type::getInt1Ty(VMContext); 851 const llvm::Type *I8Ty = llvm::Type::getInt8Ty(VMContext); 852 const llvm::Type *I32Ty = llvm::Type::getInt32Ty(VMContext); 853 854 const llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType()); 855 const llvm::Type *DBP = llvm::PointerType::get(I8Ty, DPT->getAddressSpace()); 856 if (DestPtr->getType() != DBP) 857 DestPtr = Builder.CreateBitCast(DestPtr, DBP, "tmp"); 858 859 const llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType()); 860 const llvm::Type *SBP = llvm::PointerType::get(I8Ty, SPT->getAddressSpace()); 861 if (SrcPtr->getType() != SBP) 862 SrcPtr = Builder.CreateBitCast(SrcPtr, SBP, "tmp"); 863 864 Builder.CreateCall5(CGM.getMemCpyFn(DestPtr->getType(), SrcPtr->getType(), 865 IntPtr), 866 DestPtr, SrcPtr, 867 // TypeInfo.first describes size in bits. 868 llvm::ConstantInt::get(IntPtr, TypeInfo.first/8), 869 llvm::ConstantInt::get(I32Ty, TypeInfo.second/8), 870 llvm::ConstantInt::get(I1Ty, isVolatile)); 871} 872