CGExprScalar.cpp revision 20733cd4fd5c9755cdfab583db862223c93732c8
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 // FIXME: Volatile 73 return EmitLoadOfLValue(EmitLValue(E), E->getType()); 74 } 75 76 /// EmitConversionToBool - Convert the specified expression value to a 77 /// boolean (i1) truth value. This is equivalent to "Val != 0". 78 Value *EmitConversionToBool(Value *Src, QualType DstTy); 79 80 /// EmitScalarConversion - Emit a conversion from the specified type to the 81 /// specified destination type, both of which are LLVM scalar types. 82 Value *EmitScalarConversion(Value *Src, QualType SrcTy, QualType DstTy); 83 84 /// EmitComplexToScalarConversion - Emit a conversion from the specified 85 /// complex type to the specified destination type, where the destination 86 /// type is an LLVM scalar type. 87 Value *EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src, 88 QualType SrcTy, QualType DstTy); 89 90 //===--------------------------------------------------------------------===// 91 // Visitor Methods 92 //===--------------------------------------------------------------------===// 93 94 Value *VisitStmt(Stmt *S) { 95 S->dump(CGF.getContext().getSourceManager()); 96 assert(0 && "Stmt can't have complex result type!"); 97 return 0; 98 } 99 Value *VisitExpr(Expr *S); 100 Value *VisitParenExpr(ParenExpr *PE) { return Visit(PE->getSubExpr()); } 101 102 // Leaves. 103 Value *VisitIntegerLiteral(const IntegerLiteral *E) { 104 return llvm::ConstantInt::get(E->getValue()); 105 } 106 Value *VisitFloatingLiteral(const FloatingLiteral *E) { 107 return llvm::ConstantFP::get(E->getValue()); 108 } 109 Value *VisitCharacterLiteral(const CharacterLiteral *E) { 110 return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue()); 111 } 112 Value *VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) { 113 return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue()); 114 } 115 Value *VisitCXXZeroInitValueExpr(const CXXZeroInitValueExpr *E) { 116 return llvm::Constant::getNullValue(ConvertType(E->getType())); 117 } 118 Value *VisitGNUNullExpr(const GNUNullExpr *E) { 119 return llvm::Constant::getNullValue(ConvertType(E->getType())); 120 } 121 Value *VisitTypesCompatibleExpr(const TypesCompatibleExpr *E) { 122 return llvm::ConstantInt::get(ConvertType(E->getType()), 123 CGF.getContext().typesAreCompatible( 124 E->getArgType1(), E->getArgType2())); 125 } 126 Value *VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E); 127 Value *VisitAddrLabelExpr(const AddrLabelExpr *E) { 128 llvm::Value *V = 129 llvm::ConstantInt::get(llvm::Type::Int32Ty, 130 CGF.GetIDForAddrOfLabel(E->getLabel())); 131 132 return Builder.CreateIntToPtr(V, ConvertType(E->getType())); 133 } 134 135 // l-values. 136 Value *VisitDeclRefExpr(DeclRefExpr *E) { 137 if (const EnumConstantDecl *EC = dyn_cast<EnumConstantDecl>(E->getDecl())) 138 return llvm::ConstantInt::get(EC->getInitVal()); 139 return EmitLoadOfLValue(E); 140 } 141 Value *VisitObjCSelectorExpr(ObjCSelectorExpr *E) { 142 return CGF.EmitObjCSelectorExpr(E); 143 } 144 Value *VisitObjCProtocolExpr(ObjCProtocolExpr *E) { 145 return CGF.EmitObjCProtocolExpr(E); 146 } 147 Value *VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) { 148 return EmitLoadOfLValue(E); 149 } 150 Value *VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E) { 151 return EmitLoadOfLValue(E); 152 } 153 Value *VisitObjCKVCRefExpr(ObjCKVCRefExpr *E) { 154 return EmitLoadOfLValue(E); 155 } 156 Value *VisitObjCMessageExpr(ObjCMessageExpr *E) { 157 return CGF.EmitObjCMessageExpr(E).getScalarVal(); 158 } 159 160 Value *VisitArraySubscriptExpr(ArraySubscriptExpr *E); 161 Value *VisitShuffleVectorExpr(ShuffleVectorExpr *E); 162 Value *VisitMemberExpr(Expr *E) { return EmitLoadOfLValue(E); } 163 Value *VisitExtVectorElementExpr(Expr *E) { return EmitLoadOfLValue(E); } 164 Value *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { 165 return EmitLoadOfLValue(E); 166 } 167 Value *VisitStringLiteral(Expr *E) { return EmitLValue(E).getAddress(); } 168 Value *VisitPredefinedExpr(Expr *E) { return EmitLValue(E).getAddress(); } 169 170 Value *VisitInitListExpr(InitListExpr *E) { 171 unsigned NumInitElements = E->getNumInits(); 172 173 if (E->hadArrayRangeDesignator()) { 174 CGF.ErrorUnsupported(E, "GNU array range designator extension"); 175 } 176 177 const llvm::VectorType *VType = 178 dyn_cast<llvm::VectorType>(ConvertType(E->getType())); 179 180 // We have a scalar in braces. Just use the first element. 181 if (!VType) 182 return Visit(E->getInit(0)); 183 184 unsigned NumVectorElements = VType->getNumElements(); 185 const llvm::Type *ElementType = VType->getElementType(); 186 187 // Emit individual vector element stores. 188 llvm::Value *V = llvm::UndefValue::get(VType); 189 190 // Emit initializers 191 unsigned i; 192 for (i = 0; i < NumInitElements; ++i) { 193 Value *NewV = Visit(E->getInit(i)); 194 Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 195 V = Builder.CreateInsertElement(V, NewV, Idx); 196 } 197 198 // Emit remaining default initializers 199 for (/* Do not initialize i*/; i < NumVectorElements; ++i) { 200 Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 201 llvm::Value *NewV = llvm::Constant::getNullValue(ElementType); 202 V = Builder.CreateInsertElement(V, NewV, Idx); 203 } 204 205 return V; 206 } 207 208 Value *VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) { 209 return llvm::Constant::getNullValue(ConvertType(E->getType())); 210 } 211 Value *VisitImplicitCastExpr(const ImplicitCastExpr *E); 212 Value *VisitCastExpr(const CastExpr *E) { 213 return EmitCastExpr(E->getSubExpr(), E->getType()); 214 } 215 Value *EmitCastExpr(const Expr *E, QualType T); 216 217 Value *VisitCallExpr(const CallExpr *E) { 218 return CGF.EmitCallExpr(E).getScalarVal(); 219 } 220 221 Value *VisitStmtExpr(const StmtExpr *E); 222 223 Value *VisitBlockDeclRefExpr(BlockDeclRefExpr *E); 224 225 // Unary Operators. 226 Value *VisitPrePostIncDec(const UnaryOperator *E, bool isInc, bool isPre); 227 Value *VisitUnaryPostDec(const UnaryOperator *E) { 228 return VisitPrePostIncDec(E, false, false); 229 } 230 Value *VisitUnaryPostInc(const UnaryOperator *E) { 231 return VisitPrePostIncDec(E, true, false); 232 } 233 Value *VisitUnaryPreDec(const UnaryOperator *E) { 234 return VisitPrePostIncDec(E, false, true); 235 } 236 Value *VisitUnaryPreInc(const UnaryOperator *E) { 237 return VisitPrePostIncDec(E, true, true); 238 } 239 Value *VisitUnaryAddrOf(const UnaryOperator *E) { 240 return EmitLValue(E->getSubExpr()).getAddress(); 241 } 242 Value *VisitUnaryDeref(const Expr *E) { return EmitLoadOfLValue(E); } 243 Value *VisitUnaryPlus(const UnaryOperator *E) { 244 return Visit(E->getSubExpr()); 245 } 246 Value *VisitUnaryMinus (const UnaryOperator *E); 247 Value *VisitUnaryNot (const UnaryOperator *E); 248 Value *VisitUnaryLNot (const UnaryOperator *E); 249 Value *VisitUnaryReal (const UnaryOperator *E); 250 Value *VisitUnaryImag (const UnaryOperator *E); 251 Value *VisitUnaryExtension(const UnaryOperator *E) { 252 return Visit(E->getSubExpr()); 253 } 254 Value *VisitUnaryOffsetOf(const UnaryOperator *E); 255 Value *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) { 256 return Visit(DAE->getExpr()); 257 } 258 259 // Binary Operators. 260 Value *EmitMul(const BinOpInfo &Ops) { 261 return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul"); 262 } 263 Value *EmitDiv(const BinOpInfo &Ops); 264 Value *EmitRem(const BinOpInfo &Ops); 265 Value *EmitAdd(const BinOpInfo &Ops); 266 Value *EmitSub(const BinOpInfo &Ops); 267 Value *EmitShl(const BinOpInfo &Ops); 268 Value *EmitShr(const BinOpInfo &Ops); 269 Value *EmitAnd(const BinOpInfo &Ops) { 270 return Builder.CreateAnd(Ops.LHS, Ops.RHS, "and"); 271 } 272 Value *EmitXor(const BinOpInfo &Ops) { 273 return Builder.CreateXor(Ops.LHS, Ops.RHS, "xor"); 274 } 275 Value *EmitOr (const BinOpInfo &Ops) { 276 return Builder.CreateOr(Ops.LHS, Ops.RHS, "or"); 277 } 278 279 BinOpInfo EmitBinOps(const BinaryOperator *E); 280 Value *EmitCompoundAssign(const CompoundAssignOperator *E, 281 Value *(ScalarExprEmitter::*F)(const BinOpInfo &)); 282 283 // Binary operators and binary compound assignment operators. 284#define HANDLEBINOP(OP) \ 285 Value *VisitBin ## OP(const BinaryOperator *E) { \ 286 return Emit ## OP(EmitBinOps(E)); \ 287 } \ 288 Value *VisitBin ## OP ## Assign(const CompoundAssignOperator *E) { \ 289 return EmitCompoundAssign(E, &ScalarExprEmitter::Emit ## OP); \ 290 } 291 HANDLEBINOP(Mul); 292 HANDLEBINOP(Div); 293 HANDLEBINOP(Rem); 294 HANDLEBINOP(Add); 295 HANDLEBINOP(Sub); 296 HANDLEBINOP(Shl); 297 HANDLEBINOP(Shr); 298 HANDLEBINOP(And); 299 HANDLEBINOP(Xor); 300 HANDLEBINOP(Or); 301#undef HANDLEBINOP 302 303 // Comparisons. 304 Value *EmitCompare(const BinaryOperator *E, unsigned UICmpOpc, 305 unsigned SICmpOpc, unsigned FCmpOpc); 306#define VISITCOMP(CODE, UI, SI, FP) \ 307 Value *VisitBin##CODE(const BinaryOperator *E) { \ 308 return EmitCompare(E, llvm::ICmpInst::UI, llvm::ICmpInst::SI, \ 309 llvm::FCmpInst::FP); } 310 VISITCOMP(LT, ICMP_ULT, ICMP_SLT, FCMP_OLT); 311 VISITCOMP(GT, ICMP_UGT, ICMP_SGT, FCMP_OGT); 312 VISITCOMP(LE, ICMP_ULE, ICMP_SLE, FCMP_OLE); 313 VISITCOMP(GE, ICMP_UGE, ICMP_SGE, FCMP_OGE); 314 VISITCOMP(EQ, ICMP_EQ , ICMP_EQ , FCMP_OEQ); 315 VISITCOMP(NE, ICMP_NE , ICMP_NE , FCMP_UNE); 316#undef VISITCOMP 317 318 Value *VisitBinAssign (const BinaryOperator *E); 319 320 Value *VisitBinLAnd (const BinaryOperator *E); 321 Value *VisitBinLOr (const BinaryOperator *E); 322 Value *VisitBinComma (const BinaryOperator *E); 323 324 // Other Operators. 325 Value *VisitBlockExpr(const BlockExpr *BE); 326 Value *VisitConditionalOperator(const ConditionalOperator *CO); 327 Value *VisitChooseExpr(ChooseExpr *CE); 328 Value *VisitVAArgExpr(VAArgExpr *VE); 329 Value *VisitObjCStringLiteral(const ObjCStringLiteral *E) { 330 return CGF.EmitObjCStringLiteral(E); 331 } 332 Value *VisitObjCEncodeExpr(const ObjCEncodeExpr *E); 333}; 334} // end anonymous namespace. 335 336//===----------------------------------------------------------------------===// 337// Utilities 338//===----------------------------------------------------------------------===// 339 340/// EmitConversionToBool - Convert the specified expression value to a 341/// boolean (i1) truth value. This is equivalent to "Val != 0". 342Value *ScalarExprEmitter::EmitConversionToBool(Value *Src, QualType SrcType) { 343 assert(SrcType->isCanonical() && "EmitScalarConversion strips typedefs"); 344 345 if (SrcType->isRealFloatingType()) { 346 // Compare against 0.0 for fp scalars. 347 llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType()); 348 return Builder.CreateFCmpUNE(Src, Zero, "tobool"); 349 } 350 351 assert((SrcType->isIntegerType() || isa<llvm::PointerType>(Src->getType())) && 352 "Unknown scalar type to convert"); 353 354 // Because of the type rules of C, we often end up computing a logical value, 355 // then zero extending it to int, then wanting it as a logical value again. 356 // Optimize this common case. 357 if (llvm::ZExtInst *ZI = dyn_cast<llvm::ZExtInst>(Src)) { 358 if (ZI->getOperand(0)->getType() == llvm::Type::Int1Ty) { 359 Value *Result = ZI->getOperand(0); 360 // If there aren't any more uses, zap the instruction to save space. 361 // Note that there can be more uses, for example if this 362 // is the result of an assignment. 363 if (ZI->use_empty()) 364 ZI->eraseFromParent(); 365 return Result; 366 } 367 } 368 369 // Compare against an integer or pointer null. 370 llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType()); 371 return Builder.CreateICmpNE(Src, Zero, "tobool"); 372} 373 374/// EmitScalarConversion - Emit a conversion from the specified type to the 375/// specified destination type, both of which are LLVM scalar types. 376Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType, 377 QualType DstType) { 378 SrcType = CGF.getContext().getCanonicalType(SrcType); 379 DstType = CGF.getContext().getCanonicalType(DstType); 380 if (SrcType == DstType) return Src; 381 382 if (DstType->isVoidType()) return 0; 383 384 // Handle conversions to bool first, they are special: comparisons against 0. 385 if (DstType->isBooleanType()) 386 return EmitConversionToBool(Src, SrcType); 387 388 const llvm::Type *DstTy = ConvertType(DstType); 389 390 // Ignore conversions like int -> uint. 391 if (Src->getType() == DstTy) 392 return Src; 393 394 // Handle pointer conversions next: pointers can only be converted 395 // to/from other pointers and integers. Check for pointer types in 396 // terms of LLVM, as some native types (like Obj-C id) may map to a 397 // pointer type. 398 if (isa<llvm::PointerType>(DstTy)) { 399 // The source value may be an integer, or a pointer. 400 if (isa<llvm::PointerType>(Src->getType())) 401 return Builder.CreateBitCast(Src, DstTy, "conv"); 402 assert(SrcType->isIntegerType() && "Not ptr->ptr or int->ptr conversion?"); 403 return Builder.CreateIntToPtr(Src, DstTy, "conv"); 404 } 405 406 if (isa<llvm::PointerType>(Src->getType())) { 407 // Must be an ptr to int cast. 408 assert(isa<llvm::IntegerType>(DstTy) && "not ptr->int?"); 409 return Builder.CreatePtrToInt(Src, DstTy, "conv"); 410 } 411 412 // A scalar can be splatted to an extended vector of the same element type 413 if (DstType->isExtVectorType() && !isa<VectorType>(SrcType)) { 414 // Cast the scalar to element type 415 QualType EltTy = DstType->getAsExtVectorType()->getElementType(); 416 llvm::Value *Elt = EmitScalarConversion(Src, SrcType, EltTy); 417 418 // Insert the element in element zero of an undef vector 419 llvm::Value *UnV = llvm::UndefValue::get(DstTy); 420 llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, 0); 421 UnV = Builder.CreateInsertElement(UnV, Elt, Idx, "tmp"); 422 423 // Splat the element across to all elements 424 llvm::SmallVector<llvm::Constant*, 16> Args; 425 unsigned NumElements = cast<llvm::VectorType>(DstTy)->getNumElements(); 426 for (unsigned i = 0; i < NumElements; i++) 427 Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0)); 428 429 llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements); 430 llvm::Value *Yay = Builder.CreateShuffleVector(UnV, UnV, Mask, "splat"); 431 return Yay; 432 } 433 434 // Allow bitcast from vector to integer/fp of the same size. 435 if (isa<llvm::VectorType>(Src->getType()) || 436 isa<llvm::VectorType>(DstTy)) 437 return Builder.CreateBitCast(Src, DstTy, "conv"); 438 439 // Finally, we have the arithmetic types: real int/float. 440 if (isa<llvm::IntegerType>(Src->getType())) { 441 bool InputSigned = SrcType->isSignedIntegerType(); 442 if (isa<llvm::IntegerType>(DstTy)) 443 return Builder.CreateIntCast(Src, DstTy, InputSigned, "conv"); 444 else if (InputSigned) 445 return Builder.CreateSIToFP(Src, DstTy, "conv"); 446 else 447 return Builder.CreateUIToFP(Src, DstTy, "conv"); 448 } 449 450 assert(Src->getType()->isFloatingPoint() && "Unknown real conversion"); 451 if (isa<llvm::IntegerType>(DstTy)) { 452 if (DstType->isSignedIntegerType()) 453 return Builder.CreateFPToSI(Src, DstTy, "conv"); 454 else 455 return Builder.CreateFPToUI(Src, DstTy, "conv"); 456 } 457 458 assert(DstTy->isFloatingPoint() && "Unknown real conversion"); 459 if (DstTy->getTypeID() < Src->getType()->getTypeID()) 460 return Builder.CreateFPTrunc(Src, DstTy, "conv"); 461 else 462 return Builder.CreateFPExt(Src, DstTy, "conv"); 463} 464 465/// EmitComplexToScalarConversion - Emit a conversion from the specified 466/// complex type to the specified destination type, where the destination 467/// type is an LLVM scalar type. 468Value *ScalarExprEmitter:: 469EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src, 470 QualType SrcTy, QualType DstTy) { 471 // Get the source element type. 472 SrcTy = SrcTy->getAsComplexType()->getElementType(); 473 474 // Handle conversions to bool first, they are special: comparisons against 0. 475 if (DstTy->isBooleanType()) { 476 // Complex != 0 -> (Real != 0) | (Imag != 0) 477 Src.first = EmitScalarConversion(Src.first, SrcTy, DstTy); 478 Src.second = EmitScalarConversion(Src.second, SrcTy, DstTy); 479 return Builder.CreateOr(Src.first, Src.second, "tobool"); 480 } 481 482 // C99 6.3.1.7p2: "When a value of complex type is converted to a real type, 483 // the imaginary part of the complex value is discarded and the value of the 484 // real part is converted according to the conversion rules for the 485 // corresponding real type. 486 return EmitScalarConversion(Src.first, SrcTy, DstTy); 487} 488 489 490//===----------------------------------------------------------------------===// 491// Visitor Methods 492//===----------------------------------------------------------------------===// 493 494Value *ScalarExprEmitter::VisitExpr(Expr *E) { 495 CGF.ErrorUnsupported(E, "scalar expression"); 496 if (E->getType()->isVoidType()) 497 return 0; 498 return llvm::UndefValue::get(CGF.ConvertType(E->getType())); 499} 500 501Value *ScalarExprEmitter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) { 502 llvm::SmallVector<llvm::Constant*, 32> indices; 503 for (unsigned i = 2; i < E->getNumSubExprs(); i++) { 504 indices.push_back(cast<llvm::Constant>(CGF.EmitScalarExpr(E->getExpr(i)))); 505 } 506 Value* V1 = CGF.EmitScalarExpr(E->getExpr(0)); 507 Value* V2 = CGF.EmitScalarExpr(E->getExpr(1)); 508 Value* SV = llvm::ConstantVector::get(indices.begin(), indices.size()); 509 return Builder.CreateShuffleVector(V1, V2, SV, "shuffle"); 510} 511 512Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) { 513 // Emit subscript expressions in rvalue context's. For most cases, this just 514 // loads the lvalue formed by the subscript expr. However, we have to be 515 // careful, because the base of a vector subscript is occasionally an rvalue, 516 // so we can't get it as an lvalue. 517 if (!E->getBase()->getType()->isVectorType()) 518 return EmitLoadOfLValue(E); 519 520 // Handle the vector case. The base must be a vector, the index must be an 521 // integer value. 522 Value *Base = Visit(E->getBase()); 523 Value *Idx = Visit(E->getIdx()); 524 525 // FIXME: Convert Idx to i32 type. 526 return Builder.CreateExtractElement(Base, Idx, "vecext"); 527} 528 529/// VisitImplicitCastExpr - Implicit casts are the same as normal casts, but 530/// also handle things like function to pointer-to-function decay, and array to 531/// pointer decay. 532Value *ScalarExprEmitter::VisitImplicitCastExpr(const ImplicitCastExpr *E) { 533 const Expr *Op = E->getSubExpr(); 534 535 // If this is due to array->pointer conversion, emit the array expression as 536 // an l-value. 537 if (Op->getType()->isArrayType()) { 538 // FIXME: For now we assume that all source arrays map to LLVM arrays. This 539 // will not true when we add support for VLAs. 540 Value *V = EmitLValue(Op).getAddress(); // Bitfields can't be arrays. 541 542 if (!Op->getType()->isVariableArrayType()) { 543 assert(isa<llvm::PointerType>(V->getType()) && "Expected pointer"); 544 assert(isa<llvm::ArrayType>(cast<llvm::PointerType>(V->getType()) 545 ->getElementType()) && 546 "Expected pointer to array"); 547 V = Builder.CreateStructGEP(V, 0, "arraydecay"); 548 } 549 550 // The resultant pointer type can be implicitly casted to other pointer 551 // types as well (e.g. void*) and can be implicitly converted to integer. 552 const llvm::Type *DestTy = ConvertType(E->getType()); 553 if (V->getType() != DestTy) { 554 if (isa<llvm::PointerType>(DestTy)) 555 V = Builder.CreateBitCast(V, DestTy, "ptrconv"); 556 else { 557 assert(isa<llvm::IntegerType>(DestTy) && "Unknown array decay"); 558 V = Builder.CreatePtrToInt(V, DestTy, "ptrconv"); 559 } 560 } 561 return V; 562 563 } else if (E->getType()->isReferenceType()) { 564 return EmitLValue(Op).getAddress(); 565 } 566 567 return EmitCastExpr(Op, E->getType()); 568} 569 570 571// VisitCastExpr - Emit code for an explicit or implicit cast. Implicit casts 572// have to handle a more broad range of conversions than explicit casts, as they 573// handle things like function to ptr-to-function decay etc. 574Value *ScalarExprEmitter::EmitCastExpr(const Expr *E, QualType DestTy) { 575 // Handle cases where the source is an non-complex type. 576 577 if (!CGF.hasAggregateLLVMType(E->getType())) { 578 Value *Src = Visit(const_cast<Expr*>(E)); 579 580 // Use EmitScalarConversion to perform the conversion. 581 return EmitScalarConversion(Src, E->getType(), DestTy); 582 } 583 584 if (E->getType()->isAnyComplexType()) { 585 // Handle cases where the source is a complex type. 586 return EmitComplexToScalarConversion(CGF.EmitComplexExpr(E), E->getType(), 587 DestTy); 588 } 589 590 // Okay, this is a cast from an aggregate. It must be a cast to void. Just 591 // evaluate the result and return. 592 CGF.EmitAggExpr(E, 0, false); 593 return 0; 594} 595 596Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) { 597 return CGF.EmitCompoundStmt(*E->getSubStmt(), 598 !E->getType()->isVoidType()).getScalarVal(); 599} 600 601Value *ScalarExprEmitter::VisitBlockDeclRefExpr(BlockDeclRefExpr *E) { 602 if (E->isByRef()) { 603 // FIXME: Add codegen for __block variables. 604 return VisitExpr(E); 605 } 606 607 // FIXME: We have most of the easy codegen for the helper, but we need to 608 // ensure we don't need copy/dispose, and we need to add the variables into 609 // the block literal still. 610 CGF.ErrorUnsupported(E, "scalar expression"); 611 612 uint64_t &offset = CGF.BlockDecls[E->getDecl()]; 613 614 const llvm::Type *Ty; 615 Ty = CGF.CGM.getTypes().ConvertType(E->getDecl()->getType()); 616 617 // See if we have already allocated an offset for this variable. 618 if (offset == 0) { 619 // if not, allocate one now. 620 offset = CGF.getBlockOffset(E->getDecl()); 621 } 622 623 llvm::Value *BlockLiteral = CGF.LoadBlockStruct(); 624 llvm::Value *V = Builder.CreateGEP(BlockLiteral, 625 llvm::ConstantInt::get(llvm::Type::Int64Ty, 626 offset), 627 "tmp"); 628 Ty = llvm::PointerType::get(Ty, 0); 629 if (E->isByRef()) 630 Ty = llvm::PointerType::get(Ty, 0); 631 V = Builder.CreateBitCast(V, Ty); 632 V = Builder.CreateLoad(V, false, "tmp"); 633 if (E->isByRef()) 634 V = Builder.CreateLoad(V, false, "tmp"); 635 return V; 636} 637 638//===----------------------------------------------------------------------===// 639// Unary Operators 640//===----------------------------------------------------------------------===// 641 642Value *ScalarExprEmitter::VisitPrePostIncDec(const UnaryOperator *E, 643 bool isInc, bool isPre) { 644 LValue LV = EmitLValue(E->getSubExpr()); 645 // FIXME: Handle volatile! 646 Value *InVal = CGF.EmitLoadOfLValue(LV, // false 647 E->getSubExpr()->getType()).getScalarVal(); 648 649 int AmountVal = isInc ? 1 : -1; 650 651 Value *NextVal; 652 if (isa<llvm::PointerType>(InVal->getType())) { 653 // FIXME: This isn't right for VLAs. 654 NextVal = llvm::ConstantInt::get(llvm::Type::Int32Ty, AmountVal); 655 NextVal = Builder.CreateGEP(InVal, NextVal, "ptrincdec"); 656 } else if (InVal->getType() == llvm::Type::Int1Ty && isInc) { 657 // Bool++ is an interesting case, due to promotion rules, we get: 658 // Bool++ -> Bool = Bool+1 -> Bool = (int)Bool+1 -> 659 // Bool = ((int)Bool+1) != 0 660 // An interesting aspect of this is that increment is always true. 661 // Decrement does not have this property. 662 NextVal = llvm::ConstantInt::getTrue(); 663 } else { 664 // Add the inc/dec to the real part. 665 if (isa<llvm::IntegerType>(InVal->getType())) 666 NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal); 667 else if (InVal->getType() == llvm::Type::FloatTy) 668 NextVal = 669 llvm::ConstantFP::get(llvm::APFloat(static_cast<float>(AmountVal))); 670 else if (InVal->getType() == llvm::Type::DoubleTy) 671 NextVal = 672 llvm::ConstantFP::get(llvm::APFloat(static_cast<double>(AmountVal))); 673 else { 674 llvm::APFloat F(static_cast<float>(AmountVal)); 675 bool ignored; 676 F.convert(CGF.Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero, 677 &ignored); 678 NextVal = llvm::ConstantFP::get(F); 679 } 680 NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec"); 681 } 682 683 // Store the updated result through the lvalue. 684 CGF.EmitStoreThroughLValue(RValue::get(NextVal), LV, 685 E->getSubExpr()->getType()); 686 687 // If this is a postinc, return the value read from memory, otherwise use the 688 // updated value. 689 return isPre ? NextVal : InVal; 690} 691 692 693Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) { 694 Value *Op = Visit(E->getSubExpr()); 695 return Builder.CreateNeg(Op, "neg"); 696} 697 698Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) { 699 Value *Op = Visit(E->getSubExpr()); 700 return Builder.CreateNot(Op, "neg"); 701} 702 703Value *ScalarExprEmitter::VisitUnaryLNot(const UnaryOperator *E) { 704 // Compare operand to zero. 705 Value *BoolVal = CGF.EvaluateExprAsBool(E->getSubExpr()); 706 707 // Invert value. 708 // TODO: Could dynamically modify easy computations here. For example, if 709 // the operand is an icmp ne, turn into icmp eq. 710 BoolVal = Builder.CreateNot(BoolVal, "lnot"); 711 712 // ZExt result to int. 713 return Builder.CreateZExt(BoolVal, CGF.LLVMIntTy, "lnot.ext"); 714} 715 716/// VisitSizeOfAlignOfExpr - Return the size or alignment of the type of 717/// argument of the sizeof expression as an integer. 718Value * 719ScalarExprEmitter::VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E) { 720 QualType TypeToSize = E->getTypeOfArgument(); 721 if (E->isSizeOf()) { 722 if (const VariableArrayType *VAT = 723 CGF.getContext().getAsVariableArrayType(TypeToSize)) { 724 if (E->isArgumentType()) { 725 // sizeof(type) - make sure to emit the VLA size. 726 CGF.EmitVLASize(TypeToSize); 727 } 728 729 return CGF.GetVLASize(VAT); 730 } 731 } 732 733 // If this isn't sizeof(vla), the result must be constant; use the 734 // constant folding logic so we don't have to duplicate it here. 735 Expr::EvalResult Result; 736 E->Evaluate(Result, CGF.getContext()); 737 return llvm::ConstantInt::get(Result.Val.getInt()); 738} 739 740Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E) { 741 Expr *Op = E->getSubExpr(); 742 if (Op->getType()->isAnyComplexType()) 743 return CGF.EmitComplexExpr(Op).first; 744 return Visit(Op); 745} 746Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E) { 747 Expr *Op = E->getSubExpr(); 748 if (Op->getType()->isAnyComplexType()) 749 return CGF.EmitComplexExpr(Op).second; 750 751 // __imag on a scalar returns zero. Emit it the subexpr to ensure side 752 // effects are evaluated. 753 CGF.EmitScalarExpr(Op); 754 return llvm::Constant::getNullValue(ConvertType(E->getType())); 755} 756 757Value *ScalarExprEmitter::VisitUnaryOffsetOf(const UnaryOperator *E) 758{ 759 const Expr* SubExpr = E->getSubExpr(); 760 const llvm::Type* ResultType = ConvertType(E->getType()); 761 llvm::Value* Result = llvm::Constant::getNullValue(ResultType); 762 while (!isa<CompoundLiteralExpr>(SubExpr)) { 763 if (const MemberExpr *ME = dyn_cast<MemberExpr>(SubExpr)) { 764 SubExpr = ME->getBase(); 765 QualType Ty = SubExpr->getType(); 766 767 RecordDecl *RD = Ty->getAsRecordType()->getDecl(); 768 const ASTRecordLayout &RL = CGF.getContext().getASTRecordLayout(RD); 769 FieldDecl *FD = cast<FieldDecl>(ME->getMemberDecl()); 770 771 // FIXME: This is linear time. And the fact that we're indexing 772 // into the layout by position in the record means that we're 773 // either stuck numbering the fields in the AST or we have to keep 774 // the linear search (yuck and yuck). 775 unsigned i = 0; 776 for (RecordDecl::field_iterator Field = RD->field_begin(), 777 FieldEnd = RD->field_end(); 778 Field != FieldEnd; (void)++Field, ++i) { 779 if (*Field == FD) 780 break; 781 } 782 783 llvm::Value* Offset = 784 llvm::ConstantInt::get(ResultType, RL.getFieldOffset(i) / 8); 785 Result = Builder.CreateAdd(Result, Offset); 786 } else if (const ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(SubExpr)) { 787 SubExpr = ASE->getBase(); 788 int64_t size = CGF.getContext().getTypeSize(ASE->getType()) / 8; 789 llvm::Value* ElemSize = llvm::ConstantInt::get(ResultType, size); 790 llvm::Value* ElemIndex = CGF.EmitScalarExpr(ASE->getIdx()); 791 bool IndexSigned = ASE->getIdx()->getType()->isSignedIntegerType(); 792 ElemIndex = Builder.CreateIntCast(ElemIndex, ResultType, IndexSigned); 793 llvm::Value* Offset = Builder.CreateMul(ElemSize, ElemIndex); 794 Result = Builder.CreateAdd(Result, Offset); 795 } else { 796 assert(0 && "This should be impossible!"); 797 } 798 } 799 return Result; 800} 801 802//===----------------------------------------------------------------------===// 803// Binary Operators 804//===----------------------------------------------------------------------===// 805 806BinOpInfo ScalarExprEmitter::EmitBinOps(const BinaryOperator *E) { 807 BinOpInfo Result; 808 Result.LHS = Visit(E->getLHS()); 809 Result.RHS = Visit(E->getRHS()); 810 Result.Ty = E->getType(); 811 Result.E = E; 812 return Result; 813} 814 815Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E, 816 Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) { 817 QualType LHSTy = E->getLHS()->getType(), RHSTy = E->getRHS()->getType(); 818 819 BinOpInfo OpInfo; 820 821 // Load the LHS and RHS operands. 822 LValue LHSLV = EmitLValue(E->getLHS()); 823 OpInfo.LHS = EmitLoadOfLValue(LHSLV, LHSTy); 824 825 // Determine the computation type. If the RHS is complex, then this is one of 826 // the add/sub/mul/div operators. All of these operators can be computed in 827 // with just their real component even though the computation domain really is 828 // complex. 829 QualType ComputeType = E->getComputationType(); 830 831 // If the computation type is complex, then the RHS is complex. Emit the RHS. 832 if (const ComplexType *CT = ComputeType->getAsComplexType()) { 833 ComputeType = CT->getElementType(); 834 835 // Emit the RHS, only keeping the real component. 836 OpInfo.RHS = CGF.EmitComplexExpr(E->getRHS()).first; 837 RHSTy = RHSTy->getAsComplexType()->getElementType(); 838 } else { 839 // Otherwise the RHS is a simple scalar value. 840 OpInfo.RHS = Visit(E->getRHS()); 841 } 842 843 QualType LComputeTy, RComputeTy, ResultTy; 844 845 // Compound assignment does not contain enough information about all 846 // the types involved for pointer arithmetic cases. Figure it out 847 // here for now. 848 if (E->getLHS()->getType()->isPointerType()) { 849 // Pointer arithmetic cases: ptr +=,-= int and ptr -= ptr, 850 assert((E->getOpcode() == BinaryOperator::AddAssign || 851 E->getOpcode() == BinaryOperator::SubAssign) && 852 "Invalid compound assignment operator on pointer type."); 853 LComputeTy = E->getLHS()->getType(); 854 855 if (E->getRHS()->getType()->isPointerType()) { 856 // Degenerate case of (ptr -= ptr) allowed by GCC implicit cast 857 // extension, the conversion from the pointer difference back to 858 // the LHS type is handled at the end. 859 assert(E->getOpcode() == BinaryOperator::SubAssign && 860 "Invalid compound assignment operator on pointer type."); 861 RComputeTy = E->getLHS()->getType(); 862 ResultTy = CGF.getContext().getPointerDiffType(); 863 } else { 864 RComputeTy = E->getRHS()->getType(); 865 ResultTy = LComputeTy; 866 } 867 } else if (E->getRHS()->getType()->isPointerType()) { 868 // Degenerate case of (int += ptr) allowed by GCC implicit cast 869 // extension. 870 assert(E->getOpcode() == BinaryOperator::AddAssign && 871 "Invalid compound assignment operator on pointer type."); 872 LComputeTy = E->getLHS()->getType(); 873 RComputeTy = E->getRHS()->getType(); 874 ResultTy = RComputeTy; 875 } else { 876 LComputeTy = RComputeTy = ResultTy = ComputeType; 877 } 878 879 // Convert the LHS/RHS values to the computation type. 880 OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy, LComputeTy); 881 OpInfo.RHS = EmitScalarConversion(OpInfo.RHS, RHSTy, RComputeTy); 882 OpInfo.Ty = ResultTy; 883 OpInfo.E = E; 884 885 // Expand the binary operator. 886 Value *Result = (this->*Func)(OpInfo); 887 888 // Convert the result back to the LHS type. 889 Result = EmitScalarConversion(Result, ResultTy, LHSTy); 890 891 // Store the result value into the LHS lvalue. Bit-fields are 892 // handled specially because the result is altered by the store, 893 // i.e., [C99 6.5.16p1] 'An assignment expression has the value of 894 // the left operand after the assignment...'. 895 if (LHSLV.isBitfield()) 896 CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, LHSTy, 897 &Result); 898 else 899 CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV, LHSTy); 900 901 return Result; 902} 903 904 905Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) { 906 if (Ops.LHS->getType()->isFPOrFPVector()) 907 return Builder.CreateFDiv(Ops.LHS, Ops.RHS, "div"); 908 else if (Ops.Ty->isUnsignedIntegerType()) 909 return Builder.CreateUDiv(Ops.LHS, Ops.RHS, "div"); 910 else 911 return Builder.CreateSDiv(Ops.LHS, Ops.RHS, "div"); 912} 913 914Value *ScalarExprEmitter::EmitRem(const BinOpInfo &Ops) { 915 // Rem in C can't be a floating point type: C99 6.5.5p2. 916 if (Ops.Ty->isUnsignedIntegerType()) 917 return Builder.CreateURem(Ops.LHS, Ops.RHS, "rem"); 918 else 919 return Builder.CreateSRem(Ops.LHS, Ops.RHS, "rem"); 920} 921 922 923Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &Ops) { 924 if (!Ops.Ty->isPointerType()) 925 return Builder.CreateAdd(Ops.LHS, Ops.RHS, "add"); 926 927 // FIXME: What about a pointer to a VLA? 928 Value *Ptr, *Idx; 929 Expr *IdxExp; 930 const PointerType *PT; 931 if ((PT = Ops.E->getLHS()->getType()->getAsPointerType())) { 932 Ptr = Ops.LHS; 933 Idx = Ops.RHS; 934 IdxExp = Ops.E->getRHS(); 935 } else { // int + pointer 936 PT = Ops.E->getRHS()->getType()->getAsPointerType(); 937 assert(PT && "Invalid add expr"); 938 Ptr = Ops.RHS; 939 Idx = Ops.LHS; 940 IdxExp = Ops.E->getLHS(); 941 } 942 943 unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth(); 944 if (Width < CGF.LLVMPointerWidth) { 945 // Zero or sign extend the pointer value based on whether the index is 946 // signed or not. 947 const llvm::Type *IdxType = llvm::IntegerType::get(CGF.LLVMPointerWidth); 948 if (IdxExp->getType()->isSignedIntegerType()) 949 Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext"); 950 else 951 Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext"); 952 } 953 954 // Explicitly handle GNU void* and function pointer arithmetic 955 // extensions. The GNU void* casts amount to no-ops since our void* 956 // type is i8*, but this is future proof. 957 const QualType ElementType = PT->getPointeeType(); 958 if (ElementType->isVoidType() || ElementType->isFunctionType()) { 959 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 960 Value *Casted = Builder.CreateBitCast(Ptr, i8Ty); 961 Value *Res = Builder.CreateGEP(Casted, Idx, "sub.ptr"); 962 return Builder.CreateBitCast(Res, Ptr->getType()); 963 } 964 965 return Builder.CreateGEP(Ptr, Idx, "add.ptr"); 966} 967 968Value *ScalarExprEmitter::EmitSub(const BinOpInfo &Ops) { 969 if (!isa<llvm::PointerType>(Ops.LHS->getType())) 970 return Builder.CreateSub(Ops.LHS, Ops.RHS, "sub"); 971 972 const QualType LHSType = Ops.E->getLHS()->getType(); 973 const QualType LHSElementType = LHSType->getAsPointerType()->getPointeeType(); 974 if (!isa<llvm::PointerType>(Ops.RHS->getType())) { 975 // pointer - int 976 Value *Idx = Ops.RHS; 977 unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth(); 978 if (Width < CGF.LLVMPointerWidth) { 979 // Zero or sign extend the pointer value based on whether the index is 980 // signed or not. 981 const llvm::Type *IdxType = llvm::IntegerType::get(CGF.LLVMPointerWidth); 982 if (Ops.E->getRHS()->getType()->isSignedIntegerType()) 983 Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext"); 984 else 985 Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext"); 986 } 987 Idx = Builder.CreateNeg(Idx, "sub.ptr.neg"); 988 989 // FIXME: The pointer could point to a VLA. 990 991 // Explicitly handle GNU void* and function pointer arithmetic 992 // extensions. The GNU void* casts amount to no-ops since our 993 // void* type is i8*, but this is future proof. 994 if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) { 995 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 996 Value *LHSCasted = Builder.CreateBitCast(Ops.LHS, i8Ty); 997 Value *Res = Builder.CreateGEP(LHSCasted, Idx, "sub.ptr"); 998 return Builder.CreateBitCast(Res, Ops.LHS->getType()); 999 } 1000 1001 return Builder.CreateGEP(Ops.LHS, Idx, "sub.ptr"); 1002 } else { 1003 // pointer - pointer 1004 Value *LHS = Ops.LHS; 1005 Value *RHS = Ops.RHS; 1006 1007 uint64_t ElementSize; 1008 1009 // Handle GCC extension for pointer arithmetic on void* and function pointer 1010 // types. 1011 if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) { 1012 ElementSize = 1; 1013 } else { 1014 ElementSize = CGF.getContext().getTypeSize(LHSElementType) / 8; 1015 } 1016 1017 const llvm::Type *ResultType = ConvertType(Ops.Ty); 1018 LHS = Builder.CreatePtrToInt(LHS, ResultType, "sub.ptr.lhs.cast"); 1019 RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast"); 1020 Value *BytesBetween = Builder.CreateSub(LHS, RHS, "sub.ptr.sub"); 1021 1022 // Optimize out the shift for element size of 1. 1023 if (ElementSize == 1) 1024 return BytesBetween; 1025 1026 // HACK: LLVM doesn't have an divide instruction that 'knows' there is no 1027 // remainder. As such, we handle common power-of-two cases here to generate 1028 // better code. See PR2247. 1029 if (llvm::isPowerOf2_64(ElementSize)) { 1030 Value *ShAmt = 1031 llvm::ConstantInt::get(ResultType, llvm::Log2_64(ElementSize)); 1032 return Builder.CreateAShr(BytesBetween, ShAmt, "sub.ptr.shr"); 1033 } 1034 1035 // Otherwise, do a full sdiv. 1036 Value *BytesPerElt = llvm::ConstantInt::get(ResultType, ElementSize); 1037 return Builder.CreateSDiv(BytesBetween, BytesPerElt, "sub.ptr.div"); 1038 } 1039} 1040 1041Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) { 1042 // LLVM requires the LHS and RHS to be the same type: promote or truncate the 1043 // RHS to the same size as the LHS. 1044 Value *RHS = Ops.RHS; 1045 if (Ops.LHS->getType() != RHS->getType()) 1046 RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); 1047 1048 return Builder.CreateShl(Ops.LHS, RHS, "shl"); 1049} 1050 1051Value *ScalarExprEmitter::EmitShr(const BinOpInfo &Ops) { 1052 // LLVM requires the LHS and RHS to be the same type: promote or truncate the 1053 // RHS to the same size as the LHS. 1054 Value *RHS = Ops.RHS; 1055 if (Ops.LHS->getType() != RHS->getType()) 1056 RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); 1057 1058 if (Ops.Ty->isUnsignedIntegerType()) 1059 return Builder.CreateLShr(Ops.LHS, RHS, "shr"); 1060 return Builder.CreateAShr(Ops.LHS, RHS, "shr"); 1061} 1062 1063Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,unsigned UICmpOpc, 1064 unsigned SICmpOpc, unsigned FCmpOpc) { 1065 Value *Result; 1066 QualType LHSTy = E->getLHS()->getType(); 1067 if (!LHSTy->isAnyComplexType() && !LHSTy->isVectorType()) { 1068 Value *LHS = Visit(E->getLHS()); 1069 Value *RHS = Visit(E->getRHS()); 1070 1071 if (LHS->getType()->isFloatingPoint()) { 1072 Result = Builder.CreateFCmp((llvm::CmpInst::Predicate)FCmpOpc, 1073 LHS, RHS, "cmp"); 1074 } else if (LHSTy->isSignedIntegerType()) { 1075 Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)SICmpOpc, 1076 LHS, RHS, "cmp"); 1077 } else { 1078 // Unsigned integers and pointers. 1079 Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1080 LHS, RHS, "cmp"); 1081 } 1082 } else if (LHSTy->isVectorType()) { 1083 Value *LHS = Visit(E->getLHS()); 1084 Value *RHS = Visit(E->getRHS()); 1085 1086 if (LHS->getType()->isFPOrFPVector()) { 1087 Result = Builder.CreateVFCmp((llvm::CmpInst::Predicate)FCmpOpc, 1088 LHS, RHS, "cmp"); 1089 } else if (LHSTy->isUnsignedIntegerType()) { 1090 Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)UICmpOpc, 1091 LHS, RHS, "cmp"); 1092 } else { 1093 // Signed integers and pointers. 1094 Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)SICmpOpc, 1095 LHS, RHS, "cmp"); 1096 } 1097 return Result; 1098 } else { 1099 // Complex Comparison: can only be an equality comparison. 1100 CodeGenFunction::ComplexPairTy LHS = CGF.EmitComplexExpr(E->getLHS()); 1101 CodeGenFunction::ComplexPairTy RHS = CGF.EmitComplexExpr(E->getRHS()); 1102 1103 QualType CETy = LHSTy->getAsComplexType()->getElementType(); 1104 1105 Value *ResultR, *ResultI; 1106 if (CETy->isRealFloatingType()) { 1107 ResultR = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc, 1108 LHS.first, RHS.first, "cmp.r"); 1109 ResultI = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc, 1110 LHS.second, RHS.second, "cmp.i"); 1111 } else { 1112 // Complex comparisons can only be equality comparisons. As such, signed 1113 // and unsigned opcodes are the same. 1114 ResultR = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1115 LHS.first, RHS.first, "cmp.r"); 1116 ResultI = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1117 LHS.second, RHS.second, "cmp.i"); 1118 } 1119 1120 if (E->getOpcode() == BinaryOperator::EQ) { 1121 Result = Builder.CreateAnd(ResultR, ResultI, "and.ri"); 1122 } else { 1123 assert(E->getOpcode() == BinaryOperator::NE && 1124 "Complex comparison other than == or != ?"); 1125 Result = Builder.CreateOr(ResultR, ResultI, "or.ri"); 1126 } 1127 } 1128 1129 return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType()); 1130} 1131 1132Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) { 1133 LValue LHS = EmitLValue(E->getLHS()); 1134 Value *RHS = Visit(E->getRHS()); 1135 1136 // Store the value into the LHS. Bit-fields are handled specially 1137 // because the result is altered by the store, i.e., [C99 6.5.16p1] 1138 // 'An assignment expression has the value of the left operand after 1139 // the assignment...'. 1140 // FIXME: Volatility! 1141 if (LHS.isBitfield()) 1142 CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, E->getType(), 1143 &RHS); 1144 else 1145 CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS, E->getType()); 1146 1147 // Return the RHS. 1148 return RHS; 1149} 1150 1151Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) { 1152 // If we have 0 && RHS, see if we can elide RHS, if so, just return 0. 1153 // If we have 1 && X, just emit X without inserting the control flow. 1154 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) { 1155 if (Cond == 1) { // If we have 1 && X, just emit X. 1156 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1157 // ZExt result to int. 1158 return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "land.ext"); 1159 } 1160 1161 // 0 && RHS: If it is safe, just elide the RHS, and return 0. 1162 if (!CGF.ContainsLabel(E->getRHS())) 1163 return llvm::Constant::getNullValue(CGF.LLVMIntTy); 1164 } 1165 1166 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("land.end"); 1167 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("land.rhs"); 1168 1169 // Branch on the LHS first. If it is false, go to the failure (cont) block. 1170 CGF.EmitBranchOnBoolExpr(E->getLHS(), RHSBlock, ContBlock); 1171 1172 // Any edges into the ContBlock are now from an (indeterminate number of) 1173 // edges from this first condition. All of these values will be false. Start 1174 // setting up the PHI node in the Cont Block for this. 1175 llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::Int1Ty, "", ContBlock); 1176 PN->reserveOperandSpace(2); // Normal case, two inputs. 1177 for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); 1178 PI != PE; ++PI) 1179 PN->addIncoming(llvm::ConstantInt::getFalse(), *PI); 1180 1181 CGF.EmitBlock(RHSBlock); 1182 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1183 1184 // Reaquire the RHS block, as there may be subblocks inserted. 1185 RHSBlock = Builder.GetInsertBlock(); 1186 1187 // Emit an unconditional branch from this block to ContBlock. Insert an entry 1188 // into the phi node for the edge with the value of RHSCond. 1189 CGF.EmitBlock(ContBlock); 1190 PN->addIncoming(RHSCond, RHSBlock); 1191 1192 // ZExt result to int. 1193 return Builder.CreateZExt(PN, CGF.LLVMIntTy, "land.ext"); 1194} 1195 1196Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) { 1197 // If we have 1 || RHS, see if we can elide RHS, if so, just return 1. 1198 // If we have 0 || X, just emit X without inserting the control flow. 1199 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) { 1200 if (Cond == -1) { // If we have 0 || X, just emit X. 1201 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1202 // ZExt result to int. 1203 return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "lor.ext"); 1204 } 1205 1206 // 1 || RHS: If it is safe, just elide the RHS, and return 1. 1207 if (!CGF.ContainsLabel(E->getRHS())) 1208 return llvm::ConstantInt::get(CGF.LLVMIntTy, 1); 1209 } 1210 1211 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("lor.end"); 1212 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("lor.rhs"); 1213 1214 // Branch on the LHS first. If it is true, go to the success (cont) block. 1215 CGF.EmitBranchOnBoolExpr(E->getLHS(), ContBlock, RHSBlock); 1216 1217 // Any edges into the ContBlock are now from an (indeterminate number of) 1218 // edges from this first condition. All of these values will be true. Start 1219 // setting up the PHI node in the Cont Block for this. 1220 llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::Int1Ty, "", ContBlock); 1221 PN->reserveOperandSpace(2); // Normal case, two inputs. 1222 for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); 1223 PI != PE; ++PI) 1224 PN->addIncoming(llvm::ConstantInt::getTrue(), *PI); 1225 1226 // Emit the RHS condition as a bool value. 1227 CGF.EmitBlock(RHSBlock); 1228 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1229 1230 // Reaquire the RHS block, as there may be subblocks inserted. 1231 RHSBlock = Builder.GetInsertBlock(); 1232 1233 // Emit an unconditional branch from this block to ContBlock. Insert an entry 1234 // into the phi node for the edge with the value of RHSCond. 1235 CGF.EmitBlock(ContBlock); 1236 PN->addIncoming(RHSCond, RHSBlock); 1237 1238 // ZExt result to int. 1239 return Builder.CreateZExt(PN, CGF.LLVMIntTy, "lor.ext"); 1240} 1241 1242Value *ScalarExprEmitter::VisitBinComma(const BinaryOperator *E) { 1243 CGF.EmitStmt(E->getLHS()); 1244 CGF.EnsureInsertPoint(); 1245 return Visit(E->getRHS()); 1246} 1247 1248//===----------------------------------------------------------------------===// 1249// Other Operators 1250//===----------------------------------------------------------------------===// 1251 1252/// isCheapEnoughToEvaluateUnconditionally - Return true if the specified 1253/// expression is cheap enough and side-effect-free enough to evaluate 1254/// unconditionally instead of conditionally. This is used to convert control 1255/// flow into selects in some cases. 1256static bool isCheapEnoughToEvaluateUnconditionally(const Expr *E) { 1257 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) 1258 return isCheapEnoughToEvaluateUnconditionally(PE->getSubExpr()); 1259 1260 // TODO: Allow anything we can constant fold to an integer or fp constant. 1261 if (isa<IntegerLiteral>(E) || isa<CharacterLiteral>(E) || 1262 isa<FloatingLiteral>(E)) 1263 return true; 1264 1265 // Non-volatile automatic variables too, to get "cond ? X : Y" where 1266 // X and Y are local variables. 1267 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 1268 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) 1269 if (VD->hasLocalStorage() && !VD->getType().isVolatileQualified()) 1270 return true; 1271 1272 return false; 1273} 1274 1275 1276Value *ScalarExprEmitter:: 1277VisitConditionalOperator(const ConditionalOperator *E) { 1278 // If the condition constant folds and can be elided, try to avoid emitting 1279 // the condition and the dead arm. 1280 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getCond())){ 1281 Expr *Live = E->getLHS(), *Dead = E->getRHS(); 1282 if (Cond == -1) 1283 std::swap(Live, Dead); 1284 1285 // If the dead side doesn't have labels we need, and if the Live side isn't 1286 // the gnu missing ?: extension (which we could handle, but don't bother 1287 // to), just emit the Live part. 1288 if ((!Dead || !CGF.ContainsLabel(Dead)) && // No labels in dead part 1289 Live) // Live part isn't missing. 1290 return Visit(Live); 1291 } 1292 1293 1294 // If this is a really simple expression (like x ? 4 : 5), emit this as a 1295 // select instead of as control flow. We can only do this if it is cheap and 1296 // safe to evaluate the LHS and RHS unconditionally. 1297 if (E->getLHS() && isCheapEnoughToEvaluateUnconditionally(E->getLHS()) && 1298 isCheapEnoughToEvaluateUnconditionally(E->getRHS())) { 1299 llvm::Value *CondV = CGF.EvaluateExprAsBool(E->getCond()); 1300 llvm::Value *LHS = Visit(E->getLHS()); 1301 llvm::Value *RHS = Visit(E->getRHS()); 1302 return Builder.CreateSelect(CondV, LHS, RHS, "cond"); 1303 } 1304 1305 1306 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true"); 1307 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false"); 1308 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end"); 1309 Value *CondVal = 0; 1310 1311 // If we don't have the GNU missing condition extension, emit a branch on 1312 // bool the normal way. 1313 if (E->getLHS()) { 1314 // Otherwise, just use EmitBranchOnBoolExpr to get small and simple code for 1315 // the branch on bool. 1316 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock); 1317 } else { 1318 // Otherwise, for the ?: extension, evaluate the conditional and then 1319 // convert it to bool the hard way. We do this explicitly because we need 1320 // the unconverted value for the missing middle value of the ?:. 1321 CondVal = CGF.EmitScalarExpr(E->getCond()); 1322 1323 // In some cases, EmitScalarConversion will delete the "CondVal" expression 1324 // if there are no extra uses (an optimization). Inhibit this by making an 1325 // extra dead use, because we're going to add a use of CondVal later. We 1326 // don't use the builder for this, because we don't want it to get optimized 1327 // away. This leaves dead code, but the ?: extension isn't common. 1328 new llvm::BitCastInst(CondVal, CondVal->getType(), "dummy?:holder", 1329 Builder.GetInsertBlock()); 1330 1331 Value *CondBoolVal = 1332 CGF.EmitScalarConversion(CondVal, E->getCond()->getType(), 1333 CGF.getContext().BoolTy); 1334 Builder.CreateCondBr(CondBoolVal, LHSBlock, RHSBlock); 1335 } 1336 1337 CGF.EmitBlock(LHSBlock); 1338 1339 // Handle the GNU extension for missing LHS. 1340 Value *LHS; 1341 if (E->getLHS()) 1342 LHS = Visit(E->getLHS()); 1343 else // Perform promotions, to handle cases like "short ?: int" 1344 LHS = EmitScalarConversion(CondVal, E->getCond()->getType(), E->getType()); 1345 1346 LHSBlock = Builder.GetInsertBlock(); 1347 CGF.EmitBranch(ContBlock); 1348 1349 CGF.EmitBlock(RHSBlock); 1350 1351 Value *RHS = Visit(E->getRHS()); 1352 RHSBlock = Builder.GetInsertBlock(); 1353 CGF.EmitBranch(ContBlock); 1354 1355 CGF.EmitBlock(ContBlock); 1356 1357 if (!LHS || !RHS) { 1358 assert(E->getType()->isVoidType() && "Non-void value should have a value"); 1359 return 0; 1360 } 1361 1362 // Create a PHI node for the real part. 1363 llvm::PHINode *PN = Builder.CreatePHI(LHS->getType(), "cond"); 1364 PN->reserveOperandSpace(2); 1365 PN->addIncoming(LHS, LHSBlock); 1366 PN->addIncoming(RHS, RHSBlock); 1367 return PN; 1368} 1369 1370Value *ScalarExprEmitter::VisitChooseExpr(ChooseExpr *E) { 1371 // Emit the LHS or RHS as appropriate. 1372 return 1373 Visit(E->isConditionTrue(CGF.getContext()) ? E->getLHS() : E->getRHS()); 1374} 1375 1376Value *ScalarExprEmitter::VisitVAArgExpr(VAArgExpr *VE) { 1377 llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr()); 1378 llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType()); 1379 1380 // If EmitVAArg fails, we fall back to the LLVM instruction. 1381 if (!ArgPtr) 1382 return Builder.CreateVAArg(ArgValue, ConvertType(VE->getType())); 1383 1384 // FIXME: volatile? 1385 return Builder.CreateLoad(ArgPtr); 1386} 1387 1388Value *ScalarExprEmitter::VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { 1389 std::string str; 1390 CGF.getContext().getObjCEncodingForType(E->getEncodedType(), str); 1391 1392 llvm::Constant *C = llvm::ConstantArray::get(str); 1393 C = new llvm::GlobalVariable(C->getType(), true, 1394 llvm::GlobalValue::InternalLinkage, 1395 C, ".str", &CGF.CGM.getModule()); 1396 llvm::Constant *Zero = llvm::Constant::getNullValue(llvm::Type::Int32Ty); 1397 llvm::Constant *Zeros[] = { Zero, Zero }; 1398 C = llvm::ConstantExpr::getGetElementPtr(C, Zeros, 2); 1399 1400 return C; 1401} 1402 1403 1404Value *ScalarExprEmitter::VisitBlockExpr(const BlockExpr *BE) { 1405 llvm::Constant *C = CGF.BuildBlockLiteralTmp(BE); 1406 return C; 1407} 1408 1409//===----------------------------------------------------------------------===// 1410// Entry Point into this File 1411//===----------------------------------------------------------------------===// 1412 1413/// EmitComplexExpr - Emit the computation of the specified expression of 1414/// complex type, ignoring the result. 1415Value *CodeGenFunction::EmitScalarExpr(const Expr *E) { 1416 assert(E && !hasAggregateLLVMType(E->getType()) && 1417 "Invalid scalar expression to emit"); 1418 1419 return ScalarExprEmitter(*this).Visit(const_cast<Expr*>(E)); 1420} 1421 1422/// EmitScalarConversion - Emit a conversion from the specified type to the 1423/// specified destination type, both of which are LLVM scalar types. 1424Value *CodeGenFunction::EmitScalarConversion(Value *Src, QualType SrcTy, 1425 QualType DstTy) { 1426 assert(!hasAggregateLLVMType(SrcTy) && !hasAggregateLLVMType(DstTy) && 1427 "Invalid scalar expression to emit"); 1428 return ScalarExprEmitter(*this).EmitScalarConversion(Src, SrcTy, DstTy); 1429} 1430 1431/// EmitComplexToScalarConversion - Emit a conversion from the specified 1432/// complex type to the specified destination type, where the destination 1433/// type is an LLVM scalar type. 1434Value *CodeGenFunction::EmitComplexToScalarConversion(ComplexPairTy Src, 1435 QualType SrcTy, 1436 QualType DstTy) { 1437 assert(SrcTy->isAnyComplexType() && !hasAggregateLLVMType(DstTy) && 1438 "Invalid complex -> scalar conversion"); 1439 return ScalarExprEmitter(*this).EmitComplexToScalarConversion(Src, SrcTy, 1440 DstTy); 1441} 1442 1443Value *CodeGenFunction::EmitShuffleVector(Value* V1, Value *V2, ...) { 1444 assert(V1->getType() == V2->getType() && 1445 "Vector operands must be of the same type"); 1446 unsigned NumElements = 1447 cast<llvm::VectorType>(V1->getType())->getNumElements(); 1448 1449 va_list va; 1450 va_start(va, V2); 1451 1452 llvm::SmallVector<llvm::Constant*, 16> Args; 1453 for (unsigned i = 0; i < NumElements; i++) { 1454 int n = va_arg(va, int); 1455 assert(n >= 0 && n < (int)NumElements * 2 && 1456 "Vector shuffle index out of bounds!"); 1457 Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, n)); 1458 } 1459 1460 const char *Name = va_arg(va, const char *); 1461 va_end(va); 1462 1463 llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements); 1464 1465 return Builder.CreateShuffleVector(V1, V2, Mask, Name); 1466} 1467 1468llvm::Value *CodeGenFunction::EmitVector(llvm::Value * const *Vals, 1469 unsigned NumVals, bool isSplat) { 1470 llvm::Value *Vec 1471 = llvm::UndefValue::get(llvm::VectorType::get(Vals[0]->getType(), NumVals)); 1472 1473 for (unsigned i = 0, e = NumVals; i != e; ++i) { 1474 llvm::Value *Val = isSplat ? Vals[0] : Vals[i]; 1475 llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 1476 Vec = Builder.CreateInsertElement(Vec, Val, Idx, "tmp"); 1477 } 1478 1479 return Vec; 1480} 1481