CGExprScalar.cpp revision daa24a29f881fb2ae53c4022e593eda1adf4b95b
1//===--- CGExprScalar.cpp - Emit LLVM Code for Scalar Exprs ---------------===// 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 Expr nodes with scalar LLVM types as LLVM code. 11// 12//===----------------------------------------------------------------------===// 13 14#include "CodeGenFunction.h" 15#include "CodeGenModule.h" 16#include "clang/AST/ASTContext.h" 17#include "clang/AST/DeclObjC.h" 18#include "clang/AST/RecordLayout.h" 19#include "clang/AST/StmtVisitor.h" 20#include "clang/Basic/TargetInfo.h" 21#include "llvm/Constants.h" 22#include "llvm/Function.h" 23#include "llvm/GlobalVariable.h" 24#include "llvm/Intrinsics.h" 25#include "llvm/Support/Compiler.h" 26#include "llvm/Support/CFG.h" 27#include "llvm/Target/TargetData.h" 28#include <cstdarg> 29 30using namespace clang; 31using namespace CodeGen; 32using llvm::Value; 33 34//===----------------------------------------------------------------------===// 35// Scalar Expression Emitter 36//===----------------------------------------------------------------------===// 37 38struct BinOpInfo { 39 Value *LHS; 40 Value *RHS; 41 QualType Ty; // Computation Type. 42 const BinaryOperator *E; 43}; 44 45namespace { 46class VISIBILITY_HIDDEN ScalarExprEmitter 47 : public StmtVisitor<ScalarExprEmitter, Value*> { 48 CodeGenFunction &CGF; 49 CGBuilderTy &Builder; 50 51public: 52 53 ScalarExprEmitter(CodeGenFunction &cgf) : CGF(cgf), 54 Builder(CGF.Builder) { 55 } 56 57 //===--------------------------------------------------------------------===// 58 // Utilities 59 //===--------------------------------------------------------------------===// 60 61 const llvm::Type *ConvertType(QualType T) { return CGF.ConvertType(T); } 62 LValue EmitLValue(const Expr *E) { return CGF.EmitLValue(E); } 63 64 Value *EmitLoadOfLValue(LValue LV, QualType T) { 65 return CGF.EmitLoadOfLValue(LV, T).getScalarVal(); 66 } 67 68 /// EmitLoadOfLValue - Given an expression with complex type that represents a 69 /// value l-value, this method emits the address of the l-value, then loads 70 /// and returns the result. 71 Value *EmitLoadOfLValue(const Expr *E) { 72 return EmitLoadOfLValue(EmitLValue(E), E->getType()); 73 } 74 75 /// EmitConversionToBool - Convert the specified expression value to a 76 /// boolean (i1) truth value. This is equivalent to "Val != 0". 77 Value *EmitConversionToBool(Value *Src, QualType DstTy); 78 79 /// EmitScalarConversion - Emit a conversion from the specified type to the 80 /// specified destination type, both of which are LLVM scalar types. 81 Value *EmitScalarConversion(Value *Src, QualType SrcTy, QualType DstTy); 82 83 /// EmitComplexToScalarConversion - Emit a conversion from the specified 84 /// complex type to the specified destination type, where the destination 85 /// type is an LLVM scalar type. 86 Value *EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src, 87 QualType SrcTy, QualType DstTy); 88 89 //===--------------------------------------------------------------------===// 90 // Visitor Methods 91 //===--------------------------------------------------------------------===// 92 93 Value *VisitStmt(Stmt *S) { 94 S->dump(CGF.getContext().getSourceManager()); 95 assert(0 && "Stmt can't have complex result type!"); 96 return 0; 97 } 98 Value *VisitExpr(Expr *S); 99 Value *VisitParenExpr(ParenExpr *PE) { return Visit(PE->getSubExpr()); } 100 101 // Leaves. 102 Value *VisitIntegerLiteral(const IntegerLiteral *E) { 103 return llvm::ConstantInt::get(E->getValue()); 104 } 105 Value *VisitFloatingLiteral(const FloatingLiteral *E) { 106 return llvm::ConstantFP::get(E->getValue()); 107 } 108 Value *VisitCharacterLiteral(const CharacterLiteral *E) { 109 return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue()); 110 } 111 Value *VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) { 112 return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue()); 113 } 114 Value *VisitCXXZeroInitValueExpr(const CXXZeroInitValueExpr *E) { 115 return llvm::Constant::getNullValue(ConvertType(E->getType())); 116 } 117 Value *VisitGNUNullExpr(const GNUNullExpr *E) { 118 return llvm::Constant::getNullValue(ConvertType(E->getType())); 119 } 120 Value *VisitTypesCompatibleExpr(const TypesCompatibleExpr *E) { 121 return llvm::ConstantInt::get(ConvertType(E->getType()), 122 CGF.getContext().typesAreCompatible( 123 E->getArgType1(), E->getArgType2())); 124 } 125 Value *VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E); 126 Value *VisitAddrLabelExpr(const AddrLabelExpr *E) { 127 llvm::Value *V = 128 llvm::ConstantInt::get(llvm::Type::Int32Ty, 129 CGF.GetIDForAddrOfLabel(E->getLabel())); 130 131 return Builder.CreateIntToPtr(V, ConvertType(E->getType())); 132 } 133 134 // l-values. 135 Value *VisitDeclRefExpr(DeclRefExpr *E) { 136 if (const EnumConstantDecl *EC = dyn_cast<EnumConstantDecl>(E->getDecl())) 137 return llvm::ConstantInt::get(EC->getInitVal()); 138 return EmitLoadOfLValue(E); 139 } 140 Value *VisitObjCSelectorExpr(ObjCSelectorExpr *E) { 141 return CGF.EmitObjCSelectorExpr(E); 142 } 143 Value *VisitObjCProtocolExpr(ObjCProtocolExpr *E) { 144 return CGF.EmitObjCProtocolExpr(E); 145 } 146 Value *VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) { 147 return EmitLoadOfLValue(E); 148 } 149 Value *VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E) { 150 return EmitLoadOfLValue(E); 151 } 152 Value *VisitObjCKVCRefExpr(ObjCKVCRefExpr *E) { 153 return EmitLoadOfLValue(E); 154 } 155 Value *VisitObjCMessageExpr(ObjCMessageExpr *E) { 156 return CGF.EmitObjCMessageExpr(E).getScalarVal(); 157 } 158 159 Value *VisitArraySubscriptExpr(ArraySubscriptExpr *E); 160 Value *VisitShuffleVectorExpr(ShuffleVectorExpr *E); 161 Value *VisitMemberExpr(Expr *E) { return EmitLoadOfLValue(E); } 162 Value *VisitExtVectorElementExpr(Expr *E) { return EmitLoadOfLValue(E); } 163 Value *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { 164 return EmitLoadOfLValue(E); 165 } 166 Value *VisitStringLiteral(Expr *E) { return EmitLValue(E).getAddress(); } 167 Value *VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { 168 return EmitLValue(E).getAddress(); 169 } 170 171 Value *VisitPredefinedExpr(Expr *E) { return EmitLValue(E).getAddress(); } 172 173 Value *VisitInitListExpr(InitListExpr *E) { 174 unsigned NumInitElements = E->getNumInits(); 175 176 if (E->hadArrayRangeDesignator()) { 177 CGF.ErrorUnsupported(E, "GNU array range designator extension"); 178 } 179 180 const llvm::VectorType *VType = 181 dyn_cast<llvm::VectorType>(ConvertType(E->getType())); 182 183 // We have a scalar in braces. Just use the first element. 184 if (!VType) 185 return Visit(E->getInit(0)); 186 187 unsigned NumVectorElements = VType->getNumElements(); 188 const llvm::Type *ElementType = VType->getElementType(); 189 190 // Emit individual vector element stores. 191 llvm::Value *V = llvm::UndefValue::get(VType); 192 193 // Emit initializers 194 unsigned i; 195 for (i = 0; i < NumInitElements; ++i) { 196 Value *NewV = Visit(E->getInit(i)); 197 Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 198 V = Builder.CreateInsertElement(V, NewV, Idx); 199 } 200 201 // Emit remaining default initializers 202 for (/* Do not initialize i*/; i < NumVectorElements; ++i) { 203 Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 204 llvm::Value *NewV = llvm::Constant::getNullValue(ElementType); 205 V = Builder.CreateInsertElement(V, NewV, Idx); 206 } 207 208 return V; 209 } 210 211 Value *VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) { 212 return llvm::Constant::getNullValue(ConvertType(E->getType())); 213 } 214 Value *VisitImplicitCastExpr(const ImplicitCastExpr *E); 215 Value *VisitCastExpr(const CastExpr *E) { 216 return EmitCastExpr(E->getSubExpr(), E->getType()); 217 } 218 Value *EmitCastExpr(const Expr *E, QualType T); 219 220 Value *VisitCallExpr(const CallExpr *E) { 221 return CGF.EmitCallExpr(E).getScalarVal(); 222 } 223 224 Value *VisitStmtExpr(const StmtExpr *E); 225 226 Value *VisitBlockDeclRefExpr(const BlockDeclRefExpr *E); 227 228 // Unary Operators. 229 Value *VisitPrePostIncDec(const UnaryOperator *E, bool isInc, bool isPre); 230 Value *VisitUnaryPostDec(const UnaryOperator *E) { 231 return VisitPrePostIncDec(E, false, false); 232 } 233 Value *VisitUnaryPostInc(const UnaryOperator *E) { 234 return VisitPrePostIncDec(E, true, false); 235 } 236 Value *VisitUnaryPreDec(const UnaryOperator *E) { 237 return VisitPrePostIncDec(E, false, true); 238 } 239 Value *VisitUnaryPreInc(const UnaryOperator *E) { 240 return VisitPrePostIncDec(E, true, true); 241 } 242 Value *VisitUnaryAddrOf(const UnaryOperator *E) { 243 return EmitLValue(E->getSubExpr()).getAddress(); 244 } 245 Value *VisitUnaryDeref(const Expr *E) { return EmitLoadOfLValue(E); } 246 Value *VisitUnaryPlus(const UnaryOperator *E) { 247 return Visit(E->getSubExpr()); 248 } 249 Value *VisitUnaryMinus (const UnaryOperator *E); 250 Value *VisitUnaryNot (const UnaryOperator *E); 251 Value *VisitUnaryLNot (const UnaryOperator *E); 252 Value *VisitUnaryReal (const UnaryOperator *E); 253 Value *VisitUnaryImag (const UnaryOperator *E); 254 Value *VisitUnaryExtension(const UnaryOperator *E) { 255 return Visit(E->getSubExpr()); 256 } 257 Value *VisitUnaryOffsetOf(const UnaryOperator *E); 258 Value *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) { 259 return Visit(DAE->getExpr()); 260 } 261 262 // Binary Operators. 263 Value *EmitMul(const BinOpInfo &Ops) { 264 return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul"); 265 } 266 Value *EmitDiv(const BinOpInfo &Ops); 267 Value *EmitRem(const BinOpInfo &Ops); 268 Value *EmitAdd(const BinOpInfo &Ops); 269 Value *EmitSub(const BinOpInfo &Ops); 270 Value *EmitShl(const BinOpInfo &Ops); 271 Value *EmitShr(const BinOpInfo &Ops); 272 Value *EmitAnd(const BinOpInfo &Ops) { 273 return Builder.CreateAnd(Ops.LHS, Ops.RHS, "and"); 274 } 275 Value *EmitXor(const BinOpInfo &Ops) { 276 return Builder.CreateXor(Ops.LHS, Ops.RHS, "xor"); 277 } 278 Value *EmitOr (const BinOpInfo &Ops) { 279 return Builder.CreateOr(Ops.LHS, Ops.RHS, "or"); 280 } 281 282 BinOpInfo EmitBinOps(const BinaryOperator *E); 283 Value *EmitCompoundAssign(const CompoundAssignOperator *E, 284 Value *(ScalarExprEmitter::*F)(const BinOpInfo &)); 285 286 // Binary operators and binary compound assignment operators. 287#define HANDLEBINOP(OP) \ 288 Value *VisitBin ## OP(const BinaryOperator *E) { \ 289 return Emit ## OP(EmitBinOps(E)); \ 290 } \ 291 Value *VisitBin ## OP ## Assign(const CompoundAssignOperator *E) { \ 292 return EmitCompoundAssign(E, &ScalarExprEmitter::Emit ## OP); \ 293 } 294 HANDLEBINOP(Mul); 295 HANDLEBINOP(Div); 296 HANDLEBINOP(Rem); 297 HANDLEBINOP(Add); 298 HANDLEBINOP(Sub); 299 HANDLEBINOP(Shl); 300 HANDLEBINOP(Shr); 301 HANDLEBINOP(And); 302 HANDLEBINOP(Xor); 303 HANDLEBINOP(Or); 304#undef HANDLEBINOP 305 306 // Comparisons. 307 Value *EmitCompare(const BinaryOperator *E, unsigned UICmpOpc, 308 unsigned SICmpOpc, unsigned FCmpOpc); 309#define VISITCOMP(CODE, UI, SI, FP) \ 310 Value *VisitBin##CODE(const BinaryOperator *E) { \ 311 return EmitCompare(E, llvm::ICmpInst::UI, llvm::ICmpInst::SI, \ 312 llvm::FCmpInst::FP); } 313 VISITCOMP(LT, ICMP_ULT, ICMP_SLT, FCMP_OLT); 314 VISITCOMP(GT, ICMP_UGT, ICMP_SGT, FCMP_OGT); 315 VISITCOMP(LE, ICMP_ULE, ICMP_SLE, FCMP_OLE); 316 VISITCOMP(GE, ICMP_UGE, ICMP_SGE, FCMP_OGE); 317 VISITCOMP(EQ, ICMP_EQ , ICMP_EQ , FCMP_OEQ); 318 VISITCOMP(NE, ICMP_NE , ICMP_NE , FCMP_UNE); 319#undef VISITCOMP 320 321 Value *VisitBinAssign (const BinaryOperator *E); 322 323 Value *VisitBinLAnd (const BinaryOperator *E); 324 Value *VisitBinLOr (const BinaryOperator *E); 325 Value *VisitBinComma (const BinaryOperator *E); 326 327 // Other Operators. 328 Value *VisitBlockExpr(const BlockExpr *BE); 329 Value *VisitConditionalOperator(const ConditionalOperator *CO); 330 Value *VisitChooseExpr(ChooseExpr *CE); 331 Value *VisitVAArgExpr(VAArgExpr *VE); 332 Value *VisitObjCStringLiteral(const ObjCStringLiteral *E) { 333 return CGF.EmitObjCStringLiteral(E); 334 } 335}; 336} // end anonymous namespace. 337 338//===----------------------------------------------------------------------===// 339// Utilities 340//===----------------------------------------------------------------------===// 341 342/// EmitConversionToBool - Convert the specified expression value to a 343/// boolean (i1) truth value. This is equivalent to "Val != 0". 344Value *ScalarExprEmitter::EmitConversionToBool(Value *Src, QualType SrcType) { 345 assert(SrcType->isCanonical() && "EmitScalarConversion strips typedefs"); 346 347 if (SrcType->isRealFloatingType()) { 348 // Compare against 0.0 for fp scalars. 349 llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType()); 350 return Builder.CreateFCmpUNE(Src, Zero, "tobool"); 351 } 352 353 assert((SrcType->isIntegerType() || isa<llvm::PointerType>(Src->getType())) && 354 "Unknown scalar type to convert"); 355 356 // Because of the type rules of C, we often end up computing a logical value, 357 // then zero extending it to int, then wanting it as a logical value again. 358 // Optimize this common case. 359 if (llvm::ZExtInst *ZI = dyn_cast<llvm::ZExtInst>(Src)) { 360 if (ZI->getOperand(0)->getType() == llvm::Type::Int1Ty) { 361 Value *Result = ZI->getOperand(0); 362 // If there aren't any more uses, zap the instruction to save space. 363 // Note that there can be more uses, for example if this 364 // is the result of an assignment. 365 if (ZI->use_empty()) 366 ZI->eraseFromParent(); 367 return Result; 368 } 369 } 370 371 // Compare against an integer or pointer null. 372 llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType()); 373 return Builder.CreateICmpNE(Src, Zero, "tobool"); 374} 375 376/// EmitScalarConversion - Emit a conversion from the specified type to the 377/// specified destination type, both of which are LLVM scalar types. 378Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType, 379 QualType DstType) { 380 SrcType = CGF.getContext().getCanonicalType(SrcType); 381 DstType = CGF.getContext().getCanonicalType(DstType); 382 if (SrcType == DstType) return Src; 383 384 if (DstType->isVoidType()) return 0; 385 386 // Handle conversions to bool first, they are special: comparisons against 0. 387 if (DstType->isBooleanType()) 388 return EmitConversionToBool(Src, SrcType); 389 390 const llvm::Type *DstTy = ConvertType(DstType); 391 392 // Ignore conversions like int -> uint. 393 if (Src->getType() == DstTy) 394 return Src; 395 396 // Handle pointer conversions next: pointers can only be converted 397 // to/from other pointers and integers. Check for pointer types in 398 // terms of LLVM, as some native types (like Obj-C id) may map to a 399 // pointer type. 400 if (isa<llvm::PointerType>(DstTy)) { 401 // The source value may be an integer, or a pointer. 402 if (isa<llvm::PointerType>(Src->getType())) 403 return Builder.CreateBitCast(Src, DstTy, "conv"); 404 assert(SrcType->isIntegerType() && "Not ptr->ptr or int->ptr conversion?"); 405 // First, convert to the correct width so that we control the kind of 406 // extension. 407 const llvm::Type *MiddleTy = llvm::IntegerType::get(CGF.LLVMPointerWidth); 408 bool InputSigned = SrcType->isSignedIntegerType(); 409 llvm::Value* IntResult = 410 Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv"); 411 // Then, cast to pointer. 412 return Builder.CreateIntToPtr(IntResult, DstTy, "conv"); 413 } 414 415 if (isa<llvm::PointerType>(Src->getType())) { 416 // Must be an ptr to int cast. 417 assert(isa<llvm::IntegerType>(DstTy) && "not ptr->int?"); 418 return Builder.CreatePtrToInt(Src, DstTy, "conv"); 419 } 420 421 // A scalar can be splatted to an extended vector of the same element type 422 if (DstType->isExtVectorType() && !isa<VectorType>(SrcType)) { 423 // Cast the scalar to element type 424 QualType EltTy = DstType->getAsExtVectorType()->getElementType(); 425 llvm::Value *Elt = EmitScalarConversion(Src, SrcType, EltTy); 426 427 // Insert the element in element zero of an undef vector 428 llvm::Value *UnV = llvm::UndefValue::get(DstTy); 429 llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, 0); 430 UnV = Builder.CreateInsertElement(UnV, Elt, Idx, "tmp"); 431 432 // Splat the element across to all elements 433 llvm::SmallVector<llvm::Constant*, 16> Args; 434 unsigned NumElements = cast<llvm::VectorType>(DstTy)->getNumElements(); 435 for (unsigned i = 0; i < NumElements; i++) 436 Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0)); 437 438 llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements); 439 llvm::Value *Yay = Builder.CreateShuffleVector(UnV, UnV, Mask, "splat"); 440 return Yay; 441 } 442 443 // Allow bitcast from vector to integer/fp of the same size. 444 if (isa<llvm::VectorType>(Src->getType()) || 445 isa<llvm::VectorType>(DstTy)) 446 return Builder.CreateBitCast(Src, DstTy, "conv"); 447 448 // Finally, we have the arithmetic types: real int/float. 449 if (isa<llvm::IntegerType>(Src->getType())) { 450 bool InputSigned = SrcType->isSignedIntegerType(); 451 if (isa<llvm::IntegerType>(DstTy)) 452 return Builder.CreateIntCast(Src, DstTy, InputSigned, "conv"); 453 else if (InputSigned) 454 return Builder.CreateSIToFP(Src, DstTy, "conv"); 455 else 456 return Builder.CreateUIToFP(Src, DstTy, "conv"); 457 } 458 459 assert(Src->getType()->isFloatingPoint() && "Unknown real conversion"); 460 if (isa<llvm::IntegerType>(DstTy)) { 461 if (DstType->isSignedIntegerType()) 462 return Builder.CreateFPToSI(Src, DstTy, "conv"); 463 else 464 return Builder.CreateFPToUI(Src, DstTy, "conv"); 465 } 466 467 assert(DstTy->isFloatingPoint() && "Unknown real conversion"); 468 if (DstTy->getTypeID() < Src->getType()->getTypeID()) 469 return Builder.CreateFPTrunc(Src, DstTy, "conv"); 470 else 471 return Builder.CreateFPExt(Src, DstTy, "conv"); 472} 473 474/// EmitComplexToScalarConversion - Emit a conversion from the specified 475/// complex type to the specified destination type, where the destination 476/// type is an LLVM scalar type. 477Value *ScalarExprEmitter:: 478EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src, 479 QualType SrcTy, QualType DstTy) { 480 // Get the source element type. 481 SrcTy = SrcTy->getAsComplexType()->getElementType(); 482 483 // Handle conversions to bool first, they are special: comparisons against 0. 484 if (DstTy->isBooleanType()) { 485 // Complex != 0 -> (Real != 0) | (Imag != 0) 486 Src.first = EmitScalarConversion(Src.first, SrcTy, DstTy); 487 Src.second = EmitScalarConversion(Src.second, SrcTy, DstTy); 488 return Builder.CreateOr(Src.first, Src.second, "tobool"); 489 } 490 491 // C99 6.3.1.7p2: "When a value of complex type is converted to a real type, 492 // the imaginary part of the complex value is discarded and the value of the 493 // real part is converted according to the conversion rules for the 494 // corresponding real type. 495 return EmitScalarConversion(Src.first, SrcTy, DstTy); 496} 497 498 499//===----------------------------------------------------------------------===// 500// Visitor Methods 501//===----------------------------------------------------------------------===// 502 503Value *ScalarExprEmitter::VisitExpr(Expr *E) { 504 CGF.ErrorUnsupported(E, "scalar expression"); 505 if (E->getType()->isVoidType()) 506 return 0; 507 return llvm::UndefValue::get(CGF.ConvertType(E->getType())); 508} 509 510Value *ScalarExprEmitter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) { 511 llvm::SmallVector<llvm::Constant*, 32> indices; 512 for (unsigned i = 2; i < E->getNumSubExprs(); i++) { 513 indices.push_back(cast<llvm::Constant>(CGF.EmitScalarExpr(E->getExpr(i)))); 514 } 515 Value* V1 = CGF.EmitScalarExpr(E->getExpr(0)); 516 Value* V2 = CGF.EmitScalarExpr(E->getExpr(1)); 517 Value* SV = llvm::ConstantVector::get(indices.begin(), indices.size()); 518 return Builder.CreateShuffleVector(V1, V2, SV, "shuffle"); 519} 520 521Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) { 522 // Emit subscript expressions in rvalue context's. For most cases, this just 523 // loads the lvalue formed by the subscript expr. However, we have to be 524 // careful, because the base of a vector subscript is occasionally an rvalue, 525 // so we can't get it as an lvalue. 526 if (!E->getBase()->getType()->isVectorType()) 527 return EmitLoadOfLValue(E); 528 529 // Handle the vector case. The base must be a vector, the index must be an 530 // integer value. 531 Value *Base = Visit(E->getBase()); 532 Value *Idx = Visit(E->getIdx()); 533 bool IdxSigned = E->getIdx()->getType()->isSignedIntegerType(); 534 Idx = Builder.CreateIntCast(Idx, llvm::IntegerType::get(32), 535 IdxSigned, "vecidxcast"); 536 return Builder.CreateExtractElement(Base, Idx, "vecext"); 537} 538 539/// VisitImplicitCastExpr - Implicit casts are the same as normal casts, but 540/// also handle things like function to pointer-to-function decay, and array to 541/// pointer decay. 542Value *ScalarExprEmitter::VisitImplicitCastExpr(const ImplicitCastExpr *E) { 543 const Expr *Op = E->getSubExpr(); 544 545 // If this is due to array->pointer conversion, emit the array expression as 546 // an l-value. 547 if (Op->getType()->isArrayType()) { 548 Value *V = EmitLValue(Op).getAddress(); // Bitfields can't be arrays. 549 550 // Note that VLA pointers are always decayed, so we don't need to do 551 // anything here. 552 if (!Op->getType()->isVariableArrayType()) { 553 assert(isa<llvm::PointerType>(V->getType()) && "Expected pointer"); 554 assert(isa<llvm::ArrayType>(cast<llvm::PointerType>(V->getType()) 555 ->getElementType()) && 556 "Expected pointer to array"); 557 V = Builder.CreateStructGEP(V, 0, "arraydecay"); 558 } 559 560 // The resultant pointer type can be implicitly casted to other pointer 561 // types as well (e.g. void*) and can be implicitly converted to integer. 562 const llvm::Type *DestTy = ConvertType(E->getType()); 563 if (V->getType() != DestTy) { 564 if (isa<llvm::PointerType>(DestTy)) 565 V = Builder.CreateBitCast(V, DestTy, "ptrconv"); 566 else { 567 assert(isa<llvm::IntegerType>(DestTy) && "Unknown array decay"); 568 V = Builder.CreatePtrToInt(V, DestTy, "ptrconv"); 569 } 570 } 571 return V; 572 } 573 574 return EmitCastExpr(Op, E->getType()); 575} 576 577 578// VisitCastExpr - Emit code for an explicit or implicit cast. Implicit casts 579// have to handle a more broad range of conversions than explicit casts, as they 580// handle things like function to ptr-to-function decay etc. 581Value *ScalarExprEmitter::EmitCastExpr(const Expr *E, QualType DestTy) { 582 // Handle cases where the source is an non-complex type. 583 584 if (!CGF.hasAggregateLLVMType(E->getType())) { 585 Value *Src = Visit(const_cast<Expr*>(E)); 586 587 // Use EmitScalarConversion to perform the conversion. 588 return EmitScalarConversion(Src, E->getType(), DestTy); 589 } 590 591 if (E->getType()->isAnyComplexType()) { 592 // Handle cases where the source is a complex type. 593 return EmitComplexToScalarConversion(CGF.EmitComplexExpr(E), E->getType(), 594 DestTy); 595 } 596 597 // Okay, this is a cast from an aggregate. It must be a cast to void. Just 598 // evaluate the result and return. 599 CGF.EmitAggExpr(E, 0, false); 600 return 0; 601} 602 603Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) { 604 return CGF.EmitCompoundStmt(*E->getSubStmt(), 605 !E->getType()->isVoidType()).getScalarVal(); 606} 607 608Value *ScalarExprEmitter::VisitBlockDeclRefExpr(const BlockDeclRefExpr *E) { 609 return Builder.CreateLoad(CGF.GetAddrOfBlockDecl(E), false, "tmp"); 610} 611 612//===----------------------------------------------------------------------===// 613// Unary Operators 614//===----------------------------------------------------------------------===// 615 616Value *ScalarExprEmitter::VisitPrePostIncDec(const UnaryOperator *E, 617 bool isInc, bool isPre) { 618 LValue LV = EmitLValue(E->getSubExpr()); 619 QualType ValTy = E->getSubExpr()->getType(); 620 Value *InVal = CGF.EmitLoadOfLValue(LV, ValTy).getScalarVal(); 621 622 int AmountVal = isInc ? 1 : -1; 623 624 if (ValTy->isPointerType() && 625 ValTy->getAsPointerType()->isVariableArrayType()) { 626 // The amount of the addition/subtraction needs to account for the VLA size 627 CGF.ErrorUnsupported(E, "VLA pointer inc/dec"); 628 } 629 630 Value *NextVal; 631 if (const llvm::PointerType *PT = 632 dyn_cast<llvm::PointerType>(InVal->getType())) { 633 llvm::Constant *Inc =llvm::ConstantInt::get(llvm::Type::Int32Ty, AmountVal); 634 if (!isa<llvm::FunctionType>(PT->getElementType())) { 635 NextVal = Builder.CreateGEP(InVal, Inc, "ptrincdec"); 636 } else { 637 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 638 NextVal = Builder.CreateBitCast(InVal, i8Ty, "tmp"); 639 NextVal = Builder.CreateGEP(NextVal, Inc, "ptrincdec"); 640 NextVal = Builder.CreateBitCast(NextVal, InVal->getType()); 641 } 642 } else if (InVal->getType() == llvm::Type::Int1Ty && isInc) { 643 // Bool++ is an interesting case, due to promotion rules, we get: 644 // Bool++ -> Bool = Bool+1 -> Bool = (int)Bool+1 -> 645 // Bool = ((int)Bool+1) != 0 646 // An interesting aspect of this is that increment is always true. 647 // Decrement does not have this property. 648 NextVal = llvm::ConstantInt::getTrue(); 649 } else { 650 // Add the inc/dec to the real part. 651 if (isa<llvm::IntegerType>(InVal->getType())) 652 NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal); 653 else if (InVal->getType() == llvm::Type::FloatTy) 654 NextVal = 655 llvm::ConstantFP::get(llvm::APFloat(static_cast<float>(AmountVal))); 656 else if (InVal->getType() == llvm::Type::DoubleTy) 657 NextVal = 658 llvm::ConstantFP::get(llvm::APFloat(static_cast<double>(AmountVal))); 659 else { 660 llvm::APFloat F(static_cast<float>(AmountVal)); 661 bool ignored; 662 F.convert(CGF.Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero, 663 &ignored); 664 NextVal = llvm::ConstantFP::get(F); 665 } 666 NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec"); 667 } 668 669 // Store the updated result through the lvalue. 670 if (LV.isBitfield()) 671 CGF.EmitStoreThroughBitfieldLValue(RValue::get(NextVal), LV, ValTy, 672 &NextVal); 673 else 674 CGF.EmitStoreThroughLValue(RValue::get(NextVal), LV, ValTy); 675 676 // If this is a postinc, return the value read from memory, otherwise use the 677 // updated value. 678 return isPre ? NextVal : InVal; 679} 680 681 682Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) { 683 Value *Op = Visit(E->getSubExpr()); 684 return Builder.CreateNeg(Op, "neg"); 685} 686 687Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) { 688 Value *Op = Visit(E->getSubExpr()); 689 return Builder.CreateNot(Op, "neg"); 690} 691 692Value *ScalarExprEmitter::VisitUnaryLNot(const UnaryOperator *E) { 693 // Compare operand to zero. 694 Value *BoolVal = CGF.EvaluateExprAsBool(E->getSubExpr()); 695 696 // Invert value. 697 // TODO: Could dynamically modify easy computations here. For example, if 698 // the operand is an icmp ne, turn into icmp eq. 699 BoolVal = Builder.CreateNot(BoolVal, "lnot"); 700 701 // ZExt result to int. 702 return Builder.CreateZExt(BoolVal, CGF.LLVMIntTy, "lnot.ext"); 703} 704 705/// VisitSizeOfAlignOfExpr - Return the size or alignment of the type of 706/// argument of the sizeof expression as an integer. 707Value * 708ScalarExprEmitter::VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E) { 709 QualType TypeToSize = E->getTypeOfArgument(); 710 if (E->isSizeOf()) { 711 if (const VariableArrayType *VAT = 712 CGF.getContext().getAsVariableArrayType(TypeToSize)) { 713 if (E->isArgumentType()) { 714 // sizeof(type) - make sure to emit the VLA size. 715 CGF.EmitVLASize(TypeToSize); 716 } 717 718 return CGF.GetVLASize(VAT); 719 } 720 } 721 722 // If this isn't sizeof(vla), the result must be constant; use the 723 // constant folding logic so we don't have to duplicate it here. 724 Expr::EvalResult Result; 725 E->Evaluate(Result, CGF.getContext()); 726 return llvm::ConstantInt::get(Result.Val.getInt()); 727} 728 729Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E) { 730 Expr *Op = E->getSubExpr(); 731 if (Op->getType()->isAnyComplexType()) 732 return CGF.EmitComplexExpr(Op).first; 733 return Visit(Op); 734} 735Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E) { 736 Expr *Op = E->getSubExpr(); 737 if (Op->getType()->isAnyComplexType()) 738 return CGF.EmitComplexExpr(Op).second; 739 740 // __imag on a scalar returns zero. Emit it the subexpr to ensure side 741 // effects are evaluated. 742 CGF.EmitScalarExpr(Op); 743 return llvm::Constant::getNullValue(ConvertType(E->getType())); 744} 745 746Value *ScalarExprEmitter::VisitUnaryOffsetOf(const UnaryOperator *E) 747{ 748 Value* ResultAsPtr = EmitLValue(E->getSubExpr()).getAddress(); 749 const llvm::Type* ResultType = ConvertType(E->getType()); 750 return Builder.CreatePtrToInt(ResultAsPtr, ResultType, "offsetof"); 751} 752 753//===----------------------------------------------------------------------===// 754// Binary Operators 755//===----------------------------------------------------------------------===// 756 757BinOpInfo ScalarExprEmitter::EmitBinOps(const BinaryOperator *E) { 758 BinOpInfo Result; 759 Result.LHS = Visit(E->getLHS()); 760 Result.RHS = Visit(E->getRHS()); 761 Result.Ty = E->getType(); 762 Result.E = E; 763 return Result; 764} 765 766Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E, 767 Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) { 768 QualType LHSTy = E->getLHS()->getType(), RHSTy = E->getRHS()->getType(); 769 770 BinOpInfo OpInfo; 771 772 if (E->getComputationResultType()->isAnyComplexType()) { 773 // This needs to go through the complex expression emitter, but 774 // it's a tad complicated to do that... I'm leaving it out for now. 775 // (Note that we do actually need the imaginary part of the RHS for 776 // multiplication and division.) 777 CGF.ErrorUnsupported(E, "complex compound assignment"); 778 return llvm::UndefValue::get(CGF.ConvertType(E->getType())); 779 } 780 781 // Load/convert the LHS. 782 LValue LHSLV = EmitLValue(E->getLHS()); 783 OpInfo.LHS = EmitLoadOfLValue(LHSLV, LHSTy); 784 OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy, 785 E->getComputationLHSType()); 786 // Emit the RHS. 787 OpInfo.RHS = Visit(E->getRHS()); 788 OpInfo.Ty = E->getComputationResultType(); 789 OpInfo.E = E; 790 791 // Expand the binary operator. 792 Value *Result = (this->*Func)(OpInfo); 793 794 // Convert the result back to the LHS type. 795 Result = EmitScalarConversion(Result, E->getComputationResultType(), LHSTy); 796 797 // Store the result value into the LHS lvalue. Bit-fields are 798 // handled specially because the result is altered by the store, 799 // i.e., [C99 6.5.16p1] 'An assignment expression has the value of 800 // the left operand after the assignment...'. 801 if (LHSLV.isBitfield()) 802 CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, LHSTy, 803 &Result); 804 else 805 CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV, LHSTy); 806 807 return Result; 808} 809 810 811Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) { 812 if (Ops.LHS->getType()->isFPOrFPVector()) 813 return Builder.CreateFDiv(Ops.LHS, Ops.RHS, "div"); 814 else if (Ops.Ty->isUnsignedIntegerType()) 815 return Builder.CreateUDiv(Ops.LHS, Ops.RHS, "div"); 816 else 817 return Builder.CreateSDiv(Ops.LHS, Ops.RHS, "div"); 818} 819 820Value *ScalarExprEmitter::EmitRem(const BinOpInfo &Ops) { 821 // Rem in C can't be a floating point type: C99 6.5.5p2. 822 if (Ops.Ty->isUnsignedIntegerType()) 823 return Builder.CreateURem(Ops.LHS, Ops.RHS, "rem"); 824 else 825 return Builder.CreateSRem(Ops.LHS, Ops.RHS, "rem"); 826} 827 828 829Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &Ops) { 830 if (!Ops.Ty->isPointerType()) 831 return Builder.CreateAdd(Ops.LHS, Ops.RHS, "add"); 832 833 if (Ops.Ty->getAsPointerType()->isVariableArrayType()) { 834 // The amount of the addition needs to account for the VLA size 835 CGF.ErrorUnsupported(Ops.E, "VLA pointer addition"); 836 } 837 Value *Ptr, *Idx; 838 Expr *IdxExp; 839 const PointerType *PT; 840 if ((PT = Ops.E->getLHS()->getType()->getAsPointerType())) { 841 Ptr = Ops.LHS; 842 Idx = Ops.RHS; 843 IdxExp = Ops.E->getRHS(); 844 } else { // int + pointer 845 PT = Ops.E->getRHS()->getType()->getAsPointerType(); 846 assert(PT && "Invalid add expr"); 847 Ptr = Ops.RHS; 848 Idx = Ops.LHS; 849 IdxExp = Ops.E->getLHS(); 850 } 851 852 unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth(); 853 if (Width < CGF.LLVMPointerWidth) { 854 // Zero or sign extend the pointer value based on whether the index is 855 // signed or not. 856 const llvm::Type *IdxType = llvm::IntegerType::get(CGF.LLVMPointerWidth); 857 if (IdxExp->getType()->isSignedIntegerType()) 858 Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext"); 859 else 860 Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext"); 861 } 862 863 // Explicitly handle GNU void* and function pointer arithmetic 864 // extensions. The GNU void* casts amount to no-ops since our void* 865 // type is i8*, but this is future proof. 866 const QualType ElementType = PT->getPointeeType(); 867 if (ElementType->isVoidType() || ElementType->isFunctionType()) { 868 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 869 Value *Casted = Builder.CreateBitCast(Ptr, i8Ty); 870 Value *Res = Builder.CreateGEP(Casted, Idx, "sub.ptr"); 871 return Builder.CreateBitCast(Res, Ptr->getType()); 872 } 873 874 return Builder.CreateGEP(Ptr, Idx, "add.ptr"); 875} 876 877Value *ScalarExprEmitter::EmitSub(const BinOpInfo &Ops) { 878 if (!isa<llvm::PointerType>(Ops.LHS->getType())) 879 return Builder.CreateSub(Ops.LHS, Ops.RHS, "sub"); 880 881 if (Ops.E->getLHS()->getType()->getAsPointerType()->isVariableArrayType()) { 882 // The amount of the addition needs to account for the VLA size for 883 // ptr-int 884 // The amount of the division needs to account for the VLA size for 885 // ptr-ptr. 886 CGF.ErrorUnsupported(Ops.E, "VLA pointer subtraction"); 887 } 888 889 const QualType LHSType = Ops.E->getLHS()->getType(); 890 const QualType LHSElementType = LHSType->getAsPointerType()->getPointeeType(); 891 if (!isa<llvm::PointerType>(Ops.RHS->getType())) { 892 // pointer - int 893 Value *Idx = Ops.RHS; 894 unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth(); 895 if (Width < CGF.LLVMPointerWidth) { 896 // Zero or sign extend the pointer value based on whether the index is 897 // signed or not. 898 const llvm::Type *IdxType = llvm::IntegerType::get(CGF.LLVMPointerWidth); 899 if (Ops.E->getRHS()->getType()->isSignedIntegerType()) 900 Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext"); 901 else 902 Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext"); 903 } 904 Idx = Builder.CreateNeg(Idx, "sub.ptr.neg"); 905 906 // Explicitly handle GNU void* and function pointer arithmetic 907 // extensions. The GNU void* casts amount to no-ops since our 908 // void* type is i8*, but this is future proof. 909 if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) { 910 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 911 Value *LHSCasted = Builder.CreateBitCast(Ops.LHS, i8Ty); 912 Value *Res = Builder.CreateGEP(LHSCasted, Idx, "sub.ptr"); 913 return Builder.CreateBitCast(Res, Ops.LHS->getType()); 914 } 915 916 return Builder.CreateGEP(Ops.LHS, Idx, "sub.ptr"); 917 } else { 918 // pointer - pointer 919 Value *LHS = Ops.LHS; 920 Value *RHS = Ops.RHS; 921 922 uint64_t ElementSize; 923 924 // Handle GCC extension for pointer arithmetic on void* and function pointer 925 // types. 926 if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) { 927 ElementSize = 1; 928 } else { 929 ElementSize = CGF.getContext().getTypeSize(LHSElementType) / 8; 930 } 931 932 const llvm::Type *ResultType = ConvertType(Ops.Ty); 933 LHS = Builder.CreatePtrToInt(LHS, ResultType, "sub.ptr.lhs.cast"); 934 RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast"); 935 Value *BytesBetween = Builder.CreateSub(LHS, RHS, "sub.ptr.sub"); 936 937 // Optimize out the shift for element size of 1. 938 if (ElementSize == 1) 939 return BytesBetween; 940 941 // HACK: LLVM doesn't have an divide instruction that 'knows' there is no 942 // remainder. As such, we handle common power-of-two cases here to generate 943 // better code. See PR2247. 944 if (llvm::isPowerOf2_64(ElementSize)) { 945 Value *ShAmt = 946 llvm::ConstantInt::get(ResultType, llvm::Log2_64(ElementSize)); 947 return Builder.CreateAShr(BytesBetween, ShAmt, "sub.ptr.shr"); 948 } 949 950 // Otherwise, do a full sdiv. 951 Value *BytesPerElt = llvm::ConstantInt::get(ResultType, ElementSize); 952 return Builder.CreateSDiv(BytesBetween, BytesPerElt, "sub.ptr.div"); 953 } 954} 955 956Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) { 957 // LLVM requires the LHS and RHS to be the same type: promote or truncate the 958 // RHS to the same size as the LHS. 959 Value *RHS = Ops.RHS; 960 if (Ops.LHS->getType() != RHS->getType()) 961 RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); 962 963 return Builder.CreateShl(Ops.LHS, RHS, "shl"); 964} 965 966Value *ScalarExprEmitter::EmitShr(const BinOpInfo &Ops) { 967 // LLVM requires the LHS and RHS to be the same type: promote or truncate the 968 // RHS to the same size as the LHS. 969 Value *RHS = Ops.RHS; 970 if (Ops.LHS->getType() != RHS->getType()) 971 RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); 972 973 if (Ops.Ty->isUnsignedIntegerType()) 974 return Builder.CreateLShr(Ops.LHS, RHS, "shr"); 975 return Builder.CreateAShr(Ops.LHS, RHS, "shr"); 976} 977 978Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,unsigned UICmpOpc, 979 unsigned SICmpOpc, unsigned FCmpOpc) { 980 Value *Result; 981 QualType LHSTy = E->getLHS()->getType(); 982 if (!LHSTy->isAnyComplexType() && !LHSTy->isVectorType()) { 983 Value *LHS = Visit(E->getLHS()); 984 Value *RHS = Visit(E->getRHS()); 985 986 if (LHS->getType()->isFloatingPoint()) { 987 Result = Builder.CreateFCmp((llvm::CmpInst::Predicate)FCmpOpc, 988 LHS, RHS, "cmp"); 989 } else if (LHSTy->isSignedIntegerType()) { 990 Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)SICmpOpc, 991 LHS, RHS, "cmp"); 992 } else { 993 // Unsigned integers and pointers. 994 Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 995 LHS, RHS, "cmp"); 996 } 997 } else if (LHSTy->isVectorType()) { 998 Value *LHS = Visit(E->getLHS()); 999 Value *RHS = Visit(E->getRHS()); 1000 1001 if (LHS->getType()->isFPOrFPVector()) { 1002 Result = Builder.CreateVFCmp((llvm::CmpInst::Predicate)FCmpOpc, 1003 LHS, RHS, "cmp"); 1004 } else if (LHSTy->isUnsignedIntegerType()) { 1005 Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)UICmpOpc, 1006 LHS, RHS, "cmp"); 1007 } else { 1008 // Signed integers and pointers. 1009 Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)SICmpOpc, 1010 LHS, RHS, "cmp"); 1011 } 1012 return Result; 1013 } else { 1014 // Complex Comparison: can only be an equality comparison. 1015 CodeGenFunction::ComplexPairTy LHS = CGF.EmitComplexExpr(E->getLHS()); 1016 CodeGenFunction::ComplexPairTy RHS = CGF.EmitComplexExpr(E->getRHS()); 1017 1018 QualType CETy = LHSTy->getAsComplexType()->getElementType(); 1019 1020 Value *ResultR, *ResultI; 1021 if (CETy->isRealFloatingType()) { 1022 ResultR = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc, 1023 LHS.first, RHS.first, "cmp.r"); 1024 ResultI = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc, 1025 LHS.second, RHS.second, "cmp.i"); 1026 } else { 1027 // Complex comparisons can only be equality comparisons. As such, signed 1028 // and unsigned opcodes are the same. 1029 ResultR = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1030 LHS.first, RHS.first, "cmp.r"); 1031 ResultI = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1032 LHS.second, RHS.second, "cmp.i"); 1033 } 1034 1035 if (E->getOpcode() == BinaryOperator::EQ) { 1036 Result = Builder.CreateAnd(ResultR, ResultI, "and.ri"); 1037 } else { 1038 assert(E->getOpcode() == BinaryOperator::NE && 1039 "Complex comparison other than == or != ?"); 1040 Result = Builder.CreateOr(ResultR, ResultI, "or.ri"); 1041 } 1042 } 1043 1044 return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType()); 1045} 1046 1047Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) { 1048 LValue LHS = EmitLValue(E->getLHS()); 1049 Value *RHS = Visit(E->getRHS()); 1050 1051 // Store the value into the LHS. Bit-fields are handled specially 1052 // because the result is altered by the store, i.e., [C99 6.5.16p1] 1053 // 'An assignment expression has the value of the left operand after 1054 // the assignment...'. 1055 if (LHS.isBitfield()) 1056 CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, E->getType(), 1057 &RHS); 1058 else 1059 CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS, E->getType()); 1060 1061 // Return the RHS. 1062 return RHS; 1063} 1064 1065Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) { 1066 // If we have 0 && RHS, see if we can elide RHS, if so, just return 0. 1067 // If we have 1 && X, just emit X without inserting the control flow. 1068 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) { 1069 if (Cond == 1) { // If we have 1 && X, just emit X. 1070 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1071 // ZExt result to int. 1072 return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "land.ext"); 1073 } 1074 1075 // 0 && RHS: If it is safe, just elide the RHS, and return 0. 1076 if (!CGF.ContainsLabel(E->getRHS())) 1077 return llvm::Constant::getNullValue(CGF.LLVMIntTy); 1078 } 1079 1080 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("land.end"); 1081 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("land.rhs"); 1082 1083 // Branch on the LHS first. If it is false, go to the failure (cont) block. 1084 CGF.EmitBranchOnBoolExpr(E->getLHS(), RHSBlock, ContBlock); 1085 1086 // Any edges into the ContBlock are now from an (indeterminate number of) 1087 // edges from this first condition. All of these values will be false. Start 1088 // setting up the PHI node in the Cont Block for this. 1089 llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::Int1Ty, "", ContBlock); 1090 PN->reserveOperandSpace(2); // Normal case, two inputs. 1091 for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); 1092 PI != PE; ++PI) 1093 PN->addIncoming(llvm::ConstantInt::getFalse(), *PI); 1094 1095 CGF.EmitBlock(RHSBlock); 1096 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1097 1098 // Reaquire the RHS block, as there may be subblocks inserted. 1099 RHSBlock = Builder.GetInsertBlock(); 1100 1101 // Emit an unconditional branch from this block to ContBlock. Insert an entry 1102 // into the phi node for the edge with the value of RHSCond. 1103 CGF.EmitBlock(ContBlock); 1104 PN->addIncoming(RHSCond, RHSBlock); 1105 1106 // ZExt result to int. 1107 return Builder.CreateZExt(PN, CGF.LLVMIntTy, "land.ext"); 1108} 1109 1110Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) { 1111 // If we have 1 || RHS, see if we can elide RHS, if so, just return 1. 1112 // If we have 0 || X, just emit X without inserting the control flow. 1113 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) { 1114 if (Cond == -1) { // If we have 0 || X, just emit X. 1115 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1116 // ZExt result to int. 1117 return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "lor.ext"); 1118 } 1119 1120 // 1 || RHS: If it is safe, just elide the RHS, and return 1. 1121 if (!CGF.ContainsLabel(E->getRHS())) 1122 return llvm::ConstantInt::get(CGF.LLVMIntTy, 1); 1123 } 1124 1125 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("lor.end"); 1126 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("lor.rhs"); 1127 1128 // Branch on the LHS first. If it is true, go to the success (cont) block. 1129 CGF.EmitBranchOnBoolExpr(E->getLHS(), ContBlock, RHSBlock); 1130 1131 // Any edges into the ContBlock are now from an (indeterminate number of) 1132 // edges from this first condition. All of these values will be true. Start 1133 // setting up the PHI node in the Cont Block for this. 1134 llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::Int1Ty, "", ContBlock); 1135 PN->reserveOperandSpace(2); // Normal case, two inputs. 1136 for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); 1137 PI != PE; ++PI) 1138 PN->addIncoming(llvm::ConstantInt::getTrue(), *PI); 1139 1140 // Emit the RHS condition as a bool value. 1141 CGF.EmitBlock(RHSBlock); 1142 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1143 1144 // Reaquire the RHS block, as there may be subblocks inserted. 1145 RHSBlock = Builder.GetInsertBlock(); 1146 1147 // Emit an unconditional branch from this block to ContBlock. Insert an entry 1148 // into the phi node for the edge with the value of RHSCond. 1149 CGF.EmitBlock(ContBlock); 1150 PN->addIncoming(RHSCond, RHSBlock); 1151 1152 // ZExt result to int. 1153 return Builder.CreateZExt(PN, CGF.LLVMIntTy, "lor.ext"); 1154} 1155 1156Value *ScalarExprEmitter::VisitBinComma(const BinaryOperator *E) { 1157 CGF.EmitStmt(E->getLHS()); 1158 CGF.EnsureInsertPoint(); 1159 return Visit(E->getRHS()); 1160} 1161 1162//===----------------------------------------------------------------------===// 1163// Other Operators 1164//===----------------------------------------------------------------------===// 1165 1166/// isCheapEnoughToEvaluateUnconditionally - Return true if the specified 1167/// expression is cheap enough and side-effect-free enough to evaluate 1168/// unconditionally instead of conditionally. This is used to convert control 1169/// flow into selects in some cases. 1170static bool isCheapEnoughToEvaluateUnconditionally(const Expr *E) { 1171 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) 1172 return isCheapEnoughToEvaluateUnconditionally(PE->getSubExpr()); 1173 1174 // TODO: Allow anything we can constant fold to an integer or fp constant. 1175 if (isa<IntegerLiteral>(E) || isa<CharacterLiteral>(E) || 1176 isa<FloatingLiteral>(E)) 1177 return true; 1178 1179 // Non-volatile automatic variables too, to get "cond ? X : Y" where 1180 // X and Y are local variables. 1181 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 1182 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) 1183 if (VD->hasLocalStorage() && !VD->getType().isVolatileQualified()) 1184 return true; 1185 1186 return false; 1187} 1188 1189 1190Value *ScalarExprEmitter:: 1191VisitConditionalOperator(const ConditionalOperator *E) { 1192 // If the condition constant folds and can be elided, try to avoid emitting 1193 // the condition and the dead arm. 1194 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getCond())){ 1195 Expr *Live = E->getLHS(), *Dead = E->getRHS(); 1196 if (Cond == -1) 1197 std::swap(Live, Dead); 1198 1199 // If the dead side doesn't have labels we need, and if the Live side isn't 1200 // the gnu missing ?: extension (which we could handle, but don't bother 1201 // to), just emit the Live part. 1202 if ((!Dead || !CGF.ContainsLabel(Dead)) && // No labels in dead part 1203 Live) // Live part isn't missing. 1204 return Visit(Live); 1205 } 1206 1207 1208 // If this is a really simple expression (like x ? 4 : 5), emit this as a 1209 // select instead of as control flow. We can only do this if it is cheap and 1210 // safe to evaluate the LHS and RHS unconditionally. 1211 if (E->getLHS() && isCheapEnoughToEvaluateUnconditionally(E->getLHS()) && 1212 isCheapEnoughToEvaluateUnconditionally(E->getRHS())) { 1213 llvm::Value *CondV = CGF.EvaluateExprAsBool(E->getCond()); 1214 llvm::Value *LHS = Visit(E->getLHS()); 1215 llvm::Value *RHS = Visit(E->getRHS()); 1216 return Builder.CreateSelect(CondV, LHS, RHS, "cond"); 1217 } 1218 1219 1220 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true"); 1221 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false"); 1222 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end"); 1223 Value *CondVal = 0; 1224 1225 // If we don't have the GNU missing condition extension, emit a branch on 1226 // bool the normal way. 1227 if (E->getLHS()) { 1228 // Otherwise, just use EmitBranchOnBoolExpr to get small and simple code for 1229 // the branch on bool. 1230 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock); 1231 } else { 1232 // Otherwise, for the ?: extension, evaluate the conditional and then 1233 // convert it to bool the hard way. We do this explicitly because we need 1234 // the unconverted value for the missing middle value of the ?:. 1235 CondVal = CGF.EmitScalarExpr(E->getCond()); 1236 1237 // In some cases, EmitScalarConversion will delete the "CondVal" expression 1238 // if there are no extra uses (an optimization). Inhibit this by making an 1239 // extra dead use, because we're going to add a use of CondVal later. We 1240 // don't use the builder for this, because we don't want it to get optimized 1241 // away. This leaves dead code, but the ?: extension isn't common. 1242 new llvm::BitCastInst(CondVal, CondVal->getType(), "dummy?:holder", 1243 Builder.GetInsertBlock()); 1244 1245 Value *CondBoolVal = 1246 CGF.EmitScalarConversion(CondVal, E->getCond()->getType(), 1247 CGF.getContext().BoolTy); 1248 Builder.CreateCondBr(CondBoolVal, LHSBlock, RHSBlock); 1249 } 1250 1251 CGF.EmitBlock(LHSBlock); 1252 1253 // Handle the GNU extension for missing LHS. 1254 Value *LHS; 1255 if (E->getLHS()) 1256 LHS = Visit(E->getLHS()); 1257 else // Perform promotions, to handle cases like "short ?: int" 1258 LHS = EmitScalarConversion(CondVal, E->getCond()->getType(), E->getType()); 1259 1260 LHSBlock = Builder.GetInsertBlock(); 1261 CGF.EmitBranch(ContBlock); 1262 1263 CGF.EmitBlock(RHSBlock); 1264 1265 Value *RHS = Visit(E->getRHS()); 1266 RHSBlock = Builder.GetInsertBlock(); 1267 CGF.EmitBranch(ContBlock); 1268 1269 CGF.EmitBlock(ContBlock); 1270 1271 if (!LHS || !RHS) { 1272 assert(E->getType()->isVoidType() && "Non-void value should have a value"); 1273 return 0; 1274 } 1275 1276 // Create a PHI node for the real part. 1277 llvm::PHINode *PN = Builder.CreatePHI(LHS->getType(), "cond"); 1278 PN->reserveOperandSpace(2); 1279 PN->addIncoming(LHS, LHSBlock); 1280 PN->addIncoming(RHS, RHSBlock); 1281 return PN; 1282} 1283 1284Value *ScalarExprEmitter::VisitChooseExpr(ChooseExpr *E) { 1285 return Visit(E->getChosenSubExpr(CGF.getContext())); 1286} 1287 1288Value *ScalarExprEmitter::VisitVAArgExpr(VAArgExpr *VE) { 1289 llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr()); 1290 llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType()); 1291 1292 // If EmitVAArg fails, we fall back to the LLVM instruction. 1293 if (!ArgPtr) 1294 return Builder.CreateVAArg(ArgValue, ConvertType(VE->getType())); 1295 1296 return Builder.CreateLoad(ArgPtr); 1297} 1298 1299Value *ScalarExprEmitter::VisitBlockExpr(const BlockExpr *BE) { 1300 return CGF.BuildBlockLiteralTmp(BE); 1301} 1302 1303//===----------------------------------------------------------------------===// 1304// Entry Point into this File 1305//===----------------------------------------------------------------------===// 1306 1307/// EmitComplexExpr - Emit the computation of the specified expression of 1308/// complex type, ignoring the result. 1309Value *CodeGenFunction::EmitScalarExpr(const Expr *E) { 1310 assert(E && !hasAggregateLLVMType(E->getType()) && 1311 "Invalid scalar expression to emit"); 1312 1313 return ScalarExprEmitter(*this).Visit(const_cast<Expr*>(E)); 1314} 1315 1316/// EmitScalarConversion - Emit a conversion from the specified type to the 1317/// specified destination type, both of which are LLVM scalar types. 1318Value *CodeGenFunction::EmitScalarConversion(Value *Src, QualType SrcTy, 1319 QualType DstTy) { 1320 assert(!hasAggregateLLVMType(SrcTy) && !hasAggregateLLVMType(DstTy) && 1321 "Invalid scalar expression to emit"); 1322 return ScalarExprEmitter(*this).EmitScalarConversion(Src, SrcTy, DstTy); 1323} 1324 1325/// EmitComplexToScalarConversion - Emit a conversion from the specified 1326/// complex type to the specified destination type, where the destination 1327/// type is an LLVM scalar type. 1328Value *CodeGenFunction::EmitComplexToScalarConversion(ComplexPairTy Src, 1329 QualType SrcTy, 1330 QualType DstTy) { 1331 assert(SrcTy->isAnyComplexType() && !hasAggregateLLVMType(DstTy) && 1332 "Invalid complex -> scalar conversion"); 1333 return ScalarExprEmitter(*this).EmitComplexToScalarConversion(Src, SrcTy, 1334 DstTy); 1335} 1336 1337Value *CodeGenFunction::EmitShuffleVector(Value* V1, Value *V2, ...) { 1338 assert(V1->getType() == V2->getType() && 1339 "Vector operands must be of the same type"); 1340 unsigned NumElements = 1341 cast<llvm::VectorType>(V1->getType())->getNumElements(); 1342 1343 va_list va; 1344 va_start(va, V2); 1345 1346 llvm::SmallVector<llvm::Constant*, 16> Args; 1347 for (unsigned i = 0; i < NumElements; i++) { 1348 int n = va_arg(va, int); 1349 assert(n >= 0 && n < (int)NumElements * 2 && 1350 "Vector shuffle index out of bounds!"); 1351 Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, n)); 1352 } 1353 1354 const char *Name = va_arg(va, const char *); 1355 va_end(va); 1356 1357 llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements); 1358 1359 return Builder.CreateShuffleVector(V1, V2, Mask, Name); 1360} 1361 1362llvm::Value *CodeGenFunction::EmitVector(llvm::Value * const *Vals, 1363 unsigned NumVals, bool isSplat) { 1364 llvm::Value *Vec 1365 = llvm::UndefValue::get(llvm::VectorType::get(Vals[0]->getType(), NumVals)); 1366 1367 for (unsigned i = 0, e = NumVals; i != e; ++i) { 1368 llvm::Value *Val = isSplat ? Vals[0] : Vals[i]; 1369 llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 1370 Vec = Builder.CreateInsertElement(Vec, Val, Idx, "tmp"); 1371 } 1372 1373 return Vec; 1374} 1375