CGExprScalar.cpp revision 0785570af3ef5f8c5a0377129e41efe6f3f8d770
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 <cstdarg> 28 29using namespace clang; 30using namespace CodeGen; 31using llvm::Value; 32 33//===----------------------------------------------------------------------===// 34// Scalar Expression Emitter 35//===----------------------------------------------------------------------===// 36 37struct BinOpInfo { 38 Value *LHS; 39 Value *RHS; 40 QualType Ty; // Computation Type. 41 const BinaryOperator *E; 42}; 43 44namespace { 45class VISIBILITY_HIDDEN ScalarExprEmitter 46 : public StmtVisitor<ScalarExprEmitter, Value*> { 47 CodeGenFunction &CGF; 48 CGBuilderTy &Builder; 49 50public: 51 52 ScalarExprEmitter(CodeGenFunction &cgf) : CGF(cgf), 53 Builder(CGF.Builder) { 54 } 55 56 //===--------------------------------------------------------------------===// 57 // Utilities 58 //===--------------------------------------------------------------------===// 59 60 const llvm::Type *ConvertType(QualType T) { return CGF.ConvertType(T); } 61 LValue EmitLValue(const Expr *E) { return CGF.EmitLValue(E); } 62 63 Value *EmitLoadOfLValue(LValue LV, QualType T) { 64 return CGF.EmitLoadOfLValue(LV, T).getScalarVal(); 65 } 66 67 /// EmitLoadOfLValue - Given an expression with complex type that represents a 68 /// value l-value, this method emits the address of the l-value, then loads 69 /// and returns the result. 70 Value *EmitLoadOfLValue(const Expr *E) { 71 // FIXME: Volatile 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 *VisitPredefinedExpr(Expr *E) { return EmitLValue(E).getAddress(); } 168 169 Value *VisitInitListExpr(InitListExpr *E) { 170 unsigned NumInitElements = E->getNumInits(); 171 172 if (E->hadArrayRangeDesignator()) { 173 CGF.ErrorUnsupported(E, "GNU array range designator extension"); 174 } 175 176 const llvm::VectorType *VType = 177 dyn_cast<llvm::VectorType>(ConvertType(E->getType())); 178 179 // We have a scalar in braces. Just use the first element. 180 if (!VType) 181 return Visit(E->getInit(0)); 182 183 unsigned NumVectorElements = VType->getNumElements(); 184 const llvm::Type *ElementType = VType->getElementType(); 185 186 // Emit individual vector element stores. 187 llvm::Value *V = llvm::UndefValue::get(VType); 188 189 // Emit initializers 190 unsigned i; 191 for (i = 0; i < NumInitElements; ++i) { 192 Value *NewV = Visit(E->getInit(i)); 193 Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 194 V = Builder.CreateInsertElement(V, NewV, Idx); 195 } 196 197 // Emit remaining default initializers 198 for (/* Do not initialize i*/; i < NumVectorElements; ++i) { 199 Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 200 llvm::Value *NewV = llvm::Constant::getNullValue(ElementType); 201 V = Builder.CreateInsertElement(V, NewV, Idx); 202 } 203 204 return V; 205 } 206 207 Value *VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) { 208 return llvm::Constant::getNullValue(ConvertType(E->getType())); 209 } 210 Value *VisitImplicitCastExpr(const ImplicitCastExpr *E); 211 Value *VisitCastExpr(const CastExpr *E) { 212 return EmitCastExpr(E->getSubExpr(), E->getType()); 213 } 214 Value *EmitCastExpr(const Expr *E, QualType T); 215 216 Value *VisitCallExpr(const CallExpr *E) { 217 return CGF.EmitCallExpr(E).getScalarVal(); 218 } 219 220 Value *VisitStmtExpr(const StmtExpr *E); 221 222 // Unary Operators. 223 Value *VisitPrePostIncDec(const UnaryOperator *E, bool isInc, bool isPre); 224 Value *VisitUnaryPostDec(const UnaryOperator *E) { 225 return VisitPrePostIncDec(E, false, false); 226 } 227 Value *VisitUnaryPostInc(const UnaryOperator *E) { 228 return VisitPrePostIncDec(E, true, false); 229 } 230 Value *VisitUnaryPreDec(const UnaryOperator *E) { 231 return VisitPrePostIncDec(E, false, true); 232 } 233 Value *VisitUnaryPreInc(const UnaryOperator *E) { 234 return VisitPrePostIncDec(E, true, true); 235 } 236 Value *VisitUnaryAddrOf(const UnaryOperator *E) { 237 return EmitLValue(E->getSubExpr()).getAddress(); 238 } 239 Value *VisitUnaryDeref(const Expr *E) { return EmitLoadOfLValue(E); } 240 Value *VisitUnaryPlus(const UnaryOperator *E) { 241 return Visit(E->getSubExpr()); 242 } 243 Value *VisitUnaryMinus (const UnaryOperator *E); 244 Value *VisitUnaryNot (const UnaryOperator *E); 245 Value *VisitUnaryLNot (const UnaryOperator *E); 246 Value *VisitUnaryReal (const UnaryOperator *E); 247 Value *VisitUnaryImag (const UnaryOperator *E); 248 Value *VisitUnaryExtension(const UnaryOperator *E) { 249 return Visit(E->getSubExpr()); 250 } 251 Value *VisitUnaryOffsetOf(const UnaryOperator *E); 252 Value *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) { 253 return Visit(DAE->getExpr()); 254 } 255 256 // Binary Operators. 257 Value *EmitMul(const BinOpInfo &Ops) { 258 return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul"); 259 } 260 Value *EmitDiv(const BinOpInfo &Ops); 261 Value *EmitRem(const BinOpInfo &Ops); 262 Value *EmitAdd(const BinOpInfo &Ops); 263 Value *EmitSub(const BinOpInfo &Ops); 264 Value *EmitShl(const BinOpInfo &Ops); 265 Value *EmitShr(const BinOpInfo &Ops); 266 Value *EmitAnd(const BinOpInfo &Ops) { 267 return Builder.CreateAnd(Ops.LHS, Ops.RHS, "and"); 268 } 269 Value *EmitXor(const BinOpInfo &Ops) { 270 return Builder.CreateXor(Ops.LHS, Ops.RHS, "xor"); 271 } 272 Value *EmitOr (const BinOpInfo &Ops) { 273 return Builder.CreateOr(Ops.LHS, Ops.RHS, "or"); 274 } 275 276 BinOpInfo EmitBinOps(const BinaryOperator *E); 277 Value *EmitCompoundAssign(const CompoundAssignOperator *E, 278 Value *(ScalarExprEmitter::*F)(const BinOpInfo &)); 279 280 // Binary operators and binary compound assignment operators. 281#define HANDLEBINOP(OP) \ 282 Value *VisitBin ## OP(const BinaryOperator *E) { \ 283 return Emit ## OP(EmitBinOps(E)); \ 284 } \ 285 Value *VisitBin ## OP ## Assign(const CompoundAssignOperator *E) { \ 286 return EmitCompoundAssign(E, &ScalarExprEmitter::Emit ## OP); \ 287 } 288 HANDLEBINOP(Mul); 289 HANDLEBINOP(Div); 290 HANDLEBINOP(Rem); 291 HANDLEBINOP(Add); 292 HANDLEBINOP(Sub); 293 HANDLEBINOP(Shl); 294 HANDLEBINOP(Shr); 295 HANDLEBINOP(And); 296 HANDLEBINOP(Xor); 297 HANDLEBINOP(Or); 298#undef HANDLEBINOP 299 300 // Comparisons. 301 Value *EmitCompare(const BinaryOperator *E, unsigned UICmpOpc, 302 unsigned SICmpOpc, unsigned FCmpOpc); 303#define VISITCOMP(CODE, UI, SI, FP) \ 304 Value *VisitBin##CODE(const BinaryOperator *E) { \ 305 return EmitCompare(E, llvm::ICmpInst::UI, llvm::ICmpInst::SI, \ 306 llvm::FCmpInst::FP); } 307 VISITCOMP(LT, ICMP_ULT, ICMP_SLT, FCMP_OLT); 308 VISITCOMP(GT, ICMP_UGT, ICMP_SGT, FCMP_OGT); 309 VISITCOMP(LE, ICMP_ULE, ICMP_SLE, FCMP_OLE); 310 VISITCOMP(GE, ICMP_UGE, ICMP_SGE, FCMP_OGE); 311 VISITCOMP(EQ, ICMP_EQ , ICMP_EQ , FCMP_OEQ); 312 VISITCOMP(NE, ICMP_NE , ICMP_NE , FCMP_UNE); 313#undef VISITCOMP 314 315 Value *VisitBinAssign (const BinaryOperator *E); 316 317 Value *VisitBinLAnd (const BinaryOperator *E); 318 Value *VisitBinLOr (const BinaryOperator *E); 319 Value *VisitBinComma (const BinaryOperator *E); 320 321 // Other Operators. 322 Value *VisitBlockExpr(const BlockExpr *BE) { 323 CGF.ErrorUnsupported(BE, "block expression"); 324 return llvm::UndefValue::get(CGF.ConvertType(BE->getType())); 325 } 326 327 Value *VisitConditionalOperator(const ConditionalOperator *CO); 328 Value *VisitChooseExpr(ChooseExpr *CE); 329 Value *VisitOverloadExpr(OverloadExpr *OE); 330 Value *VisitVAArgExpr(VAArgExpr *VE); 331 Value *VisitObjCStringLiteral(const ObjCStringLiteral *E) { 332 return CGF.EmitObjCStringLiteral(E); 333 } 334 Value *VisitObjCEncodeExpr(const ObjCEncodeExpr *E); 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 return Builder.CreateIntToPtr(Src, DstTy, "conv"); 406 } 407 408 if (isa<llvm::PointerType>(Src->getType())) { 409 // Must be an ptr to int cast. 410 assert(isa<llvm::IntegerType>(DstTy) && "not ptr->int?"); 411 return Builder.CreatePtrToInt(Src, DstTy, "conv"); 412 } 413 414 // A scalar can be splatted to an extended vector of the same element type 415 if (DstType->isExtVectorType() && !isa<VectorType>(SrcType)) { 416 // Cast the scalar to element type 417 QualType EltTy = DstType->getAsExtVectorType()->getElementType(); 418 llvm::Value *Elt = EmitScalarConversion(Src, SrcType, EltTy); 419 420 // Insert the element in element zero of an undef vector 421 llvm::Value *UnV = llvm::UndefValue::get(DstTy); 422 llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, 0); 423 UnV = Builder.CreateInsertElement(UnV, Elt, Idx, "tmp"); 424 425 // Splat the element across to all elements 426 llvm::SmallVector<llvm::Constant*, 16> Args; 427 unsigned NumElements = cast<llvm::VectorType>(DstTy)->getNumElements(); 428 for (unsigned i = 0; i < NumElements; i++) 429 Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0)); 430 431 llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements); 432 llvm::Value *Yay = Builder.CreateShuffleVector(UnV, UnV, Mask, "splat"); 433 return Yay; 434 } 435 436 // Allow bitcast from vector to integer/fp of the same size. 437 if (isa<llvm::VectorType>(Src->getType()) || 438 isa<llvm::VectorType>(DstTy)) 439 return Builder.CreateBitCast(Src, DstTy, "conv"); 440 441 // Finally, we have the arithmetic types: real int/float. 442 if (isa<llvm::IntegerType>(Src->getType())) { 443 bool InputSigned = SrcType->isSignedIntegerType(); 444 if (isa<llvm::IntegerType>(DstTy)) 445 return Builder.CreateIntCast(Src, DstTy, InputSigned, "conv"); 446 else if (InputSigned) 447 return Builder.CreateSIToFP(Src, DstTy, "conv"); 448 else 449 return Builder.CreateUIToFP(Src, DstTy, "conv"); 450 } 451 452 assert(Src->getType()->isFloatingPoint() && "Unknown real conversion"); 453 if (isa<llvm::IntegerType>(DstTy)) { 454 if (DstType->isSignedIntegerType()) 455 return Builder.CreateFPToSI(Src, DstTy, "conv"); 456 else 457 return Builder.CreateFPToUI(Src, DstTy, "conv"); 458 } 459 460 assert(DstTy->isFloatingPoint() && "Unknown real conversion"); 461 if (DstTy->getTypeID() < Src->getType()->getTypeID()) 462 return Builder.CreateFPTrunc(Src, DstTy, "conv"); 463 else 464 return Builder.CreateFPExt(Src, DstTy, "conv"); 465} 466 467/// EmitComplexToScalarConversion - Emit a conversion from the specified 468/// complex type to the specified destination type, where the destination 469/// type is an LLVM scalar type. 470Value *ScalarExprEmitter:: 471EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src, 472 QualType SrcTy, QualType DstTy) { 473 // Get the source element type. 474 SrcTy = SrcTy->getAsComplexType()->getElementType(); 475 476 // Handle conversions to bool first, they are special: comparisons against 0. 477 if (DstTy->isBooleanType()) { 478 // Complex != 0 -> (Real != 0) | (Imag != 0) 479 Src.first = EmitScalarConversion(Src.first, SrcTy, DstTy); 480 Src.second = EmitScalarConversion(Src.second, SrcTy, DstTy); 481 return Builder.CreateOr(Src.first, Src.second, "tobool"); 482 } 483 484 // C99 6.3.1.7p2: "When a value of complex type is converted to a real type, 485 // the imaginary part of the complex value is discarded and the value of the 486 // real part is converted according to the conversion rules for the 487 // corresponding real type. 488 return EmitScalarConversion(Src.first, SrcTy, DstTy); 489} 490 491 492//===----------------------------------------------------------------------===// 493// Visitor Methods 494//===----------------------------------------------------------------------===// 495 496Value *ScalarExprEmitter::VisitExpr(Expr *E) { 497 CGF.ErrorUnsupported(E, "scalar expression"); 498 if (E->getType()->isVoidType()) 499 return 0; 500 return llvm::UndefValue::get(CGF.ConvertType(E->getType())); 501} 502 503Value *ScalarExprEmitter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) { 504 llvm::SmallVector<llvm::Constant*, 32> indices; 505 for (unsigned i = 2; i < E->getNumSubExprs(); i++) { 506 indices.push_back(cast<llvm::Constant>(CGF.EmitScalarExpr(E->getExpr(i)))); 507 } 508 Value* V1 = CGF.EmitScalarExpr(E->getExpr(0)); 509 Value* V2 = CGF.EmitScalarExpr(E->getExpr(1)); 510 Value* SV = llvm::ConstantVector::get(indices.begin(), indices.size()); 511 return Builder.CreateShuffleVector(V1, V2, SV, "shuffle"); 512} 513 514Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) { 515 // Emit subscript expressions in rvalue context's. For most cases, this just 516 // loads the lvalue formed by the subscript expr. However, we have to be 517 // careful, because the base of a vector subscript is occasionally an rvalue, 518 // so we can't get it as an lvalue. 519 if (!E->getBase()->getType()->isVectorType()) 520 return EmitLoadOfLValue(E); 521 522 // Handle the vector case. The base must be a vector, the index must be an 523 // integer value. 524 Value *Base = Visit(E->getBase()); 525 Value *Idx = Visit(E->getIdx()); 526 527 // FIXME: Convert Idx to i32 type. 528 return Builder.CreateExtractElement(Base, Idx, "vecext"); 529} 530 531/// VisitImplicitCastExpr - Implicit casts are the same as normal casts, but 532/// also handle things like function to pointer-to-function decay, and array to 533/// pointer decay. 534Value *ScalarExprEmitter::VisitImplicitCastExpr(const ImplicitCastExpr *E) { 535 const Expr *Op = E->getSubExpr(); 536 537 // If this is due to array->pointer conversion, emit the array expression as 538 // an l-value. 539 if (Op->getType()->isArrayType()) { 540 // FIXME: For now we assume that all source arrays map to LLVM arrays. This 541 // will not true when we add support for VLAs. 542 Value *V = EmitLValue(Op).getAddress(); // Bitfields can't be arrays. 543 544 if (!Op->getType()->isVariableArrayType()) { 545 assert(isa<llvm::PointerType>(V->getType()) && "Expected pointer"); 546 assert(isa<llvm::ArrayType>(cast<llvm::PointerType>(V->getType()) 547 ->getElementType()) && 548 "Expected pointer to array"); 549 V = Builder.CreateStructGEP(V, 0, "arraydecay"); 550 } 551 552 // The resultant pointer type can be implicitly casted to other pointer 553 // types as well (e.g. void*) and can be implicitly converted to integer. 554 const llvm::Type *DestTy = ConvertType(E->getType()); 555 if (V->getType() != DestTy) { 556 if (isa<llvm::PointerType>(DestTy)) 557 V = Builder.CreateBitCast(V, DestTy, "ptrconv"); 558 else { 559 assert(isa<llvm::IntegerType>(DestTy) && "Unknown array decay"); 560 V = Builder.CreatePtrToInt(V, DestTy, "ptrconv"); 561 } 562 } 563 return V; 564 565 } else if (E->getType()->isReferenceType()) { 566 return EmitLValue(Op).getAddress(); 567 } 568 569 return EmitCastExpr(Op, E->getType()); 570} 571 572 573// VisitCastExpr - Emit code for an explicit or implicit cast. Implicit casts 574// have to handle a more broad range of conversions than explicit casts, as they 575// handle things like function to ptr-to-function decay etc. 576Value *ScalarExprEmitter::EmitCastExpr(const Expr *E, QualType DestTy) { 577 // Handle cases where the source is an non-complex type. 578 579 if (!CGF.hasAggregateLLVMType(E->getType())) { 580 Value *Src = Visit(const_cast<Expr*>(E)); 581 582 // Use EmitScalarConversion to perform the conversion. 583 return EmitScalarConversion(Src, E->getType(), DestTy); 584 } 585 586 if (E->getType()->isAnyComplexType()) { 587 // Handle cases where the source is a complex type. 588 return EmitComplexToScalarConversion(CGF.EmitComplexExpr(E), E->getType(), 589 DestTy); 590 } 591 592 // Okay, this is a cast from an aggregate. It must be a cast to void. Just 593 // evaluate the result and return. 594 CGF.EmitAggExpr(E, 0, false); 595 return 0; 596} 597 598Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) { 599 return CGF.EmitCompoundStmt(*E->getSubStmt(), 600 !E->getType()->isVoidType()).getScalarVal(); 601} 602 603 604//===----------------------------------------------------------------------===// 605// Unary Operators 606//===----------------------------------------------------------------------===// 607 608Value *ScalarExprEmitter::VisitPrePostIncDec(const UnaryOperator *E, 609 bool isInc, bool isPre) { 610 LValue LV = EmitLValue(E->getSubExpr()); 611 // FIXME: Handle volatile! 612 Value *InVal = CGF.EmitLoadOfLValue(LV, // false 613 E->getSubExpr()->getType()).getScalarVal(); 614 615 int AmountVal = isInc ? 1 : -1; 616 617 Value *NextVal; 618 if (isa<llvm::PointerType>(InVal->getType())) { 619 // FIXME: This isn't right for VLAs. 620 NextVal = llvm::ConstantInt::get(llvm::Type::Int32Ty, AmountVal); 621 NextVal = Builder.CreateGEP(InVal, NextVal, "ptrincdec"); 622 } else if (InVal->getType() == llvm::Type::Int1Ty && isInc) { 623 // Bool++ is an interesting case, due to promotion rules, we get: 624 // Bool++ -> Bool = Bool+1 -> Bool = (int)Bool+1 -> 625 // Bool = ((int)Bool+1) != 0 626 // An interesting aspect of this is that increment is always true. 627 // Decrement does not have this property. 628 NextVal = llvm::ConstantInt::getTrue(); 629 } else { 630 // Add the inc/dec to the real part. 631 if (isa<llvm::IntegerType>(InVal->getType())) 632 NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal); 633 else if (InVal->getType() == llvm::Type::FloatTy) 634 NextVal = 635 llvm::ConstantFP::get(llvm::APFloat(static_cast<float>(AmountVal))); 636 else if (InVal->getType() == llvm::Type::DoubleTy) 637 NextVal = 638 llvm::ConstantFP::get(llvm::APFloat(static_cast<double>(AmountVal))); 639 else { 640 llvm::APFloat F(static_cast<float>(AmountVal)); 641 bool ignored; 642 F.convert(CGF.Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero, 643 &ignored); 644 NextVal = llvm::ConstantFP::get(F); 645 } 646 NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec"); 647 } 648 649 // Store the updated result through the lvalue. 650 CGF.EmitStoreThroughLValue(RValue::get(NextVal), LV, 651 E->getSubExpr()->getType()); 652 653 // If this is a postinc, return the value read from memory, otherwise use the 654 // updated value. 655 return isPre ? NextVal : InVal; 656} 657 658 659Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) { 660 Value *Op = Visit(E->getSubExpr()); 661 return Builder.CreateNeg(Op, "neg"); 662} 663 664Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) { 665 Value *Op = Visit(E->getSubExpr()); 666 return Builder.CreateNot(Op, "neg"); 667} 668 669Value *ScalarExprEmitter::VisitUnaryLNot(const UnaryOperator *E) { 670 // Compare operand to zero. 671 Value *BoolVal = CGF.EvaluateExprAsBool(E->getSubExpr()); 672 673 // Invert value. 674 // TODO: Could dynamically modify easy computations here. For example, if 675 // the operand is an icmp ne, turn into icmp eq. 676 BoolVal = Builder.CreateNot(BoolVal, "lnot"); 677 678 // ZExt result to int. 679 return Builder.CreateZExt(BoolVal, CGF.LLVMIntTy, "lnot.ext"); 680} 681 682/// VisitSizeOfAlignOfExpr - Return the size or alignment of the type of 683/// argument of the sizeof expression as an integer. 684Value * 685ScalarExprEmitter::VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E) { 686 QualType TypeToSize = E->getTypeOfArgument(); 687 if (E->isSizeOf()) { 688 if (const VariableArrayType *VAT = 689 CGF.getContext().getAsVariableArrayType(TypeToSize)) { 690 if (E->isArgumentType()) { 691 // sizeof(type) - make sure to emit the VLA size. 692 CGF.EmitVLASize(TypeToSize); 693 } 694 695 return CGF.GetVLASize(VAT); 696 } 697 } 698 699 // If this isn't sizeof(vla), the result must be constant; use the 700 // constant folding logic so we don't have to duplicate it here. 701 Expr::EvalResult Result; 702 E->Evaluate(Result, CGF.getContext()); 703 return llvm::ConstantInt::get(Result.Val.getInt()); 704} 705 706Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E) { 707 Expr *Op = E->getSubExpr(); 708 if (Op->getType()->isAnyComplexType()) 709 return CGF.EmitComplexExpr(Op).first; 710 return Visit(Op); 711} 712Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E) { 713 Expr *Op = E->getSubExpr(); 714 if (Op->getType()->isAnyComplexType()) 715 return CGF.EmitComplexExpr(Op).second; 716 717 // __imag on a scalar returns zero. Emit it the subexpr to ensure side 718 // effects are evaluated. 719 CGF.EmitScalarExpr(Op); 720 return llvm::Constant::getNullValue(ConvertType(E->getType())); 721} 722 723Value *ScalarExprEmitter::VisitUnaryOffsetOf(const UnaryOperator *E) 724{ 725 const Expr* SubExpr = E->getSubExpr(); 726 const llvm::Type* ResultType = ConvertType(E->getType()); 727 llvm::Value* Result = llvm::Constant::getNullValue(ResultType); 728 while (!isa<CompoundLiteralExpr>(SubExpr)) { 729 if (const MemberExpr *ME = dyn_cast<MemberExpr>(SubExpr)) { 730 SubExpr = ME->getBase(); 731 QualType Ty = SubExpr->getType(); 732 733 RecordDecl *RD = Ty->getAsRecordType()->getDecl(); 734 const ASTRecordLayout &RL = CGF.getContext().getASTRecordLayout(RD); 735 FieldDecl *FD = cast<FieldDecl>(ME->getMemberDecl()); 736 737 // FIXME: This is linear time. And the fact that we're indexing 738 // into the layout by position in the record means that we're 739 // either stuck numbering the fields in the AST or we have to keep 740 // the linear search (yuck and yuck). 741 unsigned i = 0; 742 for (RecordDecl::field_iterator Field = RD->field_begin(), 743 FieldEnd = RD->field_end(); 744 Field != FieldEnd; (void)++Field, ++i) { 745 if (*Field == FD) 746 break; 747 } 748 749 llvm::Value* Offset = 750 llvm::ConstantInt::get(ResultType, RL.getFieldOffset(i) / 8); 751 Result = Builder.CreateAdd(Result, Offset); 752 } else if (const ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(SubExpr)) { 753 SubExpr = ASE->getBase(); 754 int64_t size = CGF.getContext().getTypeSize(ASE->getType()) / 8; 755 llvm::Value* ElemSize = llvm::ConstantInt::get(ResultType, size); 756 llvm::Value* ElemIndex = CGF.EmitScalarExpr(ASE->getIdx()); 757 bool IndexSigned = ASE->getIdx()->getType()->isSignedIntegerType(); 758 ElemIndex = Builder.CreateIntCast(ElemIndex, ResultType, IndexSigned); 759 llvm::Value* Offset = Builder.CreateMul(ElemSize, ElemIndex); 760 Result = Builder.CreateAdd(Result, Offset); 761 } else { 762 assert(0 && "This should be impossible!"); 763 } 764 } 765 return Result; 766} 767 768//===----------------------------------------------------------------------===// 769// Binary Operators 770//===----------------------------------------------------------------------===// 771 772BinOpInfo ScalarExprEmitter::EmitBinOps(const BinaryOperator *E) { 773 BinOpInfo Result; 774 Result.LHS = Visit(E->getLHS()); 775 Result.RHS = Visit(E->getRHS()); 776 Result.Ty = E->getType(); 777 Result.E = E; 778 return Result; 779} 780 781Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E, 782 Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) { 783 QualType LHSTy = E->getLHS()->getType(), RHSTy = E->getRHS()->getType(); 784 785 BinOpInfo OpInfo; 786 787 // Load the LHS and RHS operands. 788 LValue LHSLV = EmitLValue(E->getLHS()); 789 OpInfo.LHS = EmitLoadOfLValue(LHSLV, LHSTy); 790 791 // Determine the computation type. If the RHS is complex, then this is one of 792 // the add/sub/mul/div operators. All of these operators can be computed in 793 // with just their real component even though the computation domain really is 794 // complex. 795 QualType ComputeType = E->getComputationType(); 796 797 // If the computation type is complex, then the RHS is complex. Emit the RHS. 798 if (const ComplexType *CT = ComputeType->getAsComplexType()) { 799 ComputeType = CT->getElementType(); 800 801 // Emit the RHS, only keeping the real component. 802 OpInfo.RHS = CGF.EmitComplexExpr(E->getRHS()).first; 803 RHSTy = RHSTy->getAsComplexType()->getElementType(); 804 } else { 805 // Otherwise the RHS is a simple scalar value. 806 OpInfo.RHS = Visit(E->getRHS()); 807 } 808 809 QualType LComputeTy, RComputeTy, ResultTy; 810 811 // Compound assignment does not contain enough information about all 812 // the types involved for pointer arithmetic cases. Figure it out 813 // here for now. 814 if (E->getLHS()->getType()->isPointerType()) { 815 // Pointer arithmetic cases: ptr +=,-= int and ptr -= ptr, 816 assert((E->getOpcode() == BinaryOperator::AddAssign || 817 E->getOpcode() == BinaryOperator::SubAssign) && 818 "Invalid compound assignment operator on pointer type."); 819 LComputeTy = E->getLHS()->getType(); 820 821 if (E->getRHS()->getType()->isPointerType()) { 822 // Degenerate case of (ptr -= ptr) allowed by GCC implicit cast 823 // extension, the conversion from the pointer difference back to 824 // the LHS type is handled at the end. 825 assert(E->getOpcode() == BinaryOperator::SubAssign && 826 "Invalid compound assignment operator on pointer type."); 827 RComputeTy = E->getLHS()->getType(); 828 ResultTy = CGF.getContext().getPointerDiffType(); 829 } else { 830 RComputeTy = E->getRHS()->getType(); 831 ResultTy = LComputeTy; 832 } 833 } else if (E->getRHS()->getType()->isPointerType()) { 834 // Degenerate case of (int += ptr) allowed by GCC implicit cast 835 // extension. 836 assert(E->getOpcode() == BinaryOperator::AddAssign && 837 "Invalid compound assignment operator on pointer type."); 838 LComputeTy = E->getLHS()->getType(); 839 RComputeTy = E->getRHS()->getType(); 840 ResultTy = RComputeTy; 841 } else { 842 LComputeTy = RComputeTy = ResultTy = ComputeType; 843 } 844 845 // Convert the LHS/RHS values to the computation type. 846 OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy, LComputeTy); 847 OpInfo.RHS = EmitScalarConversion(OpInfo.RHS, RHSTy, RComputeTy); 848 OpInfo.Ty = ResultTy; 849 OpInfo.E = E; 850 851 // Expand the binary operator. 852 Value *Result = (this->*Func)(OpInfo); 853 854 // Convert the result back to the LHS type. 855 Result = EmitScalarConversion(Result, ResultTy, LHSTy); 856 857 // Store the result value into the LHS lvalue. Bit-fields are 858 // handled specially because the result is altered by the store, 859 // i.e., [C99 6.5.16p1] 'An assignment expression has the value of 860 // the left operand after the assignment...'. 861 if (LHSLV.isBitfield()) 862 CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, LHSTy, 863 &Result); 864 else 865 CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV, LHSTy); 866 867 return Result; 868} 869 870 871Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) { 872 if (Ops.LHS->getType()->isFPOrFPVector()) 873 return Builder.CreateFDiv(Ops.LHS, Ops.RHS, "div"); 874 else if (Ops.Ty->isUnsignedIntegerType()) 875 return Builder.CreateUDiv(Ops.LHS, Ops.RHS, "div"); 876 else 877 return Builder.CreateSDiv(Ops.LHS, Ops.RHS, "div"); 878} 879 880Value *ScalarExprEmitter::EmitRem(const BinOpInfo &Ops) { 881 // Rem in C can't be a floating point type: C99 6.5.5p2. 882 if (Ops.Ty->isUnsignedIntegerType()) 883 return Builder.CreateURem(Ops.LHS, Ops.RHS, "rem"); 884 else 885 return Builder.CreateSRem(Ops.LHS, Ops.RHS, "rem"); 886} 887 888 889Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &Ops) { 890 if (!Ops.Ty->isPointerType()) 891 return Builder.CreateAdd(Ops.LHS, Ops.RHS, "add"); 892 893 // FIXME: What about a pointer to a VLA? 894 Value *Ptr, *Idx; 895 Expr *IdxExp; 896 const PointerType *PT; 897 if ((PT = Ops.E->getLHS()->getType()->getAsPointerType())) { 898 Ptr = Ops.LHS; 899 Idx = Ops.RHS; 900 IdxExp = Ops.E->getRHS(); 901 } else { // int + pointer 902 PT = Ops.E->getRHS()->getType()->getAsPointerType(); 903 assert(PT && "Invalid add expr"); 904 Ptr = Ops.RHS; 905 Idx = Ops.LHS; 906 IdxExp = Ops.E->getLHS(); 907 } 908 909 unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth(); 910 if (Width < CGF.LLVMPointerWidth) { 911 // Zero or sign extend the pointer value based on whether the index is 912 // signed or not. 913 const llvm::Type *IdxType = llvm::IntegerType::get(CGF.LLVMPointerWidth); 914 if (IdxExp->getType()->isSignedIntegerType()) 915 Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext"); 916 else 917 Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext"); 918 } 919 920 // Explicitly handle GNU void* and function pointer arithmetic 921 // extensions. The GNU void* casts amount to no-ops since our void* 922 // type is i8*, but this is future proof. 923 const QualType ElementType = PT->getPointeeType(); 924 if (ElementType->isVoidType() || ElementType->isFunctionType()) { 925 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 926 Value *Casted = Builder.CreateBitCast(Ptr, i8Ty); 927 Value *Res = Builder.CreateGEP(Casted, Idx, "sub.ptr"); 928 return Builder.CreateBitCast(Res, Ptr->getType()); 929 } 930 931 return Builder.CreateGEP(Ptr, Idx, "add.ptr"); 932} 933 934Value *ScalarExprEmitter::EmitSub(const BinOpInfo &Ops) { 935 if (!isa<llvm::PointerType>(Ops.LHS->getType())) 936 return Builder.CreateSub(Ops.LHS, Ops.RHS, "sub"); 937 938 const QualType LHSType = Ops.E->getLHS()->getType(); 939 const QualType LHSElementType = LHSType->getAsPointerType()->getPointeeType(); 940 if (!isa<llvm::PointerType>(Ops.RHS->getType())) { 941 // pointer - int 942 Value *Idx = Ops.RHS; 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 (Ops.E->getRHS()->getType()->isSignedIntegerType()) 949 Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext"); 950 else 951 Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext"); 952 } 953 Idx = Builder.CreateNeg(Idx, "sub.ptr.neg"); 954 955 // FIXME: The pointer could point to a VLA. 956 957 // Explicitly handle GNU void* and function pointer arithmetic 958 // extensions. The GNU void* casts amount to no-ops since our 959 // void* type is i8*, but this is future proof. 960 if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) { 961 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 962 Value *LHSCasted = Builder.CreateBitCast(Ops.LHS, i8Ty); 963 Value *Res = Builder.CreateGEP(LHSCasted, Idx, "sub.ptr"); 964 return Builder.CreateBitCast(Res, Ops.LHS->getType()); 965 } 966 967 return Builder.CreateGEP(Ops.LHS, Idx, "sub.ptr"); 968 } else { 969 // pointer - pointer 970 Value *LHS = Ops.LHS; 971 Value *RHS = Ops.RHS; 972 973 uint64_t ElementSize; 974 975 // Handle GCC extension for pointer arithmetic on void* and function pointer 976 // types. 977 if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) { 978 ElementSize = 1; 979 } else { 980 ElementSize = CGF.getContext().getTypeSize(LHSElementType) / 8; 981 } 982 983 const llvm::Type *ResultType = ConvertType(Ops.Ty); 984 LHS = Builder.CreatePtrToInt(LHS, ResultType, "sub.ptr.lhs.cast"); 985 RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast"); 986 Value *BytesBetween = Builder.CreateSub(LHS, RHS, "sub.ptr.sub"); 987 988 // Optimize out the shift for element size of 1. 989 if (ElementSize == 1) 990 return BytesBetween; 991 992 // HACK: LLVM doesn't have an divide instruction that 'knows' there is no 993 // remainder. As such, we handle common power-of-two cases here to generate 994 // better code. See PR2247. 995 if (llvm::isPowerOf2_64(ElementSize)) { 996 Value *ShAmt = 997 llvm::ConstantInt::get(ResultType, llvm::Log2_64(ElementSize)); 998 return Builder.CreateAShr(BytesBetween, ShAmt, "sub.ptr.shr"); 999 } 1000 1001 // Otherwise, do a full sdiv. 1002 Value *BytesPerElt = llvm::ConstantInt::get(ResultType, ElementSize); 1003 return Builder.CreateSDiv(BytesBetween, BytesPerElt, "sub.ptr.div"); 1004 } 1005} 1006 1007Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) { 1008 // LLVM requires the LHS and RHS to be the same type: promote or truncate the 1009 // RHS to the same size as the LHS. 1010 Value *RHS = Ops.RHS; 1011 if (Ops.LHS->getType() != RHS->getType()) 1012 RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); 1013 1014 return Builder.CreateShl(Ops.LHS, RHS, "shl"); 1015} 1016 1017Value *ScalarExprEmitter::EmitShr(const BinOpInfo &Ops) { 1018 // LLVM requires the LHS and RHS to be the same type: promote or truncate the 1019 // RHS to the same size as the LHS. 1020 Value *RHS = Ops.RHS; 1021 if (Ops.LHS->getType() != RHS->getType()) 1022 RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); 1023 1024 if (Ops.Ty->isUnsignedIntegerType()) 1025 return Builder.CreateLShr(Ops.LHS, RHS, "shr"); 1026 return Builder.CreateAShr(Ops.LHS, RHS, "shr"); 1027} 1028 1029Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,unsigned UICmpOpc, 1030 unsigned SICmpOpc, unsigned FCmpOpc) { 1031 Value *Result; 1032 QualType LHSTy = E->getLHS()->getType(); 1033 if (!LHSTy->isAnyComplexType() && !LHSTy->isVectorType()) { 1034 Value *LHS = Visit(E->getLHS()); 1035 Value *RHS = Visit(E->getRHS()); 1036 1037 if (LHS->getType()->isFloatingPoint()) { 1038 Result = Builder.CreateFCmp((llvm::CmpInst::Predicate)FCmpOpc, 1039 LHS, RHS, "cmp"); 1040 } else if (LHSTy->isSignedIntegerType()) { 1041 Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)SICmpOpc, 1042 LHS, RHS, "cmp"); 1043 } else { 1044 // Unsigned integers and pointers. 1045 Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1046 LHS, RHS, "cmp"); 1047 } 1048 } else if (LHSTy->isVectorType()) { 1049 Value *LHS = Visit(E->getLHS()); 1050 Value *RHS = Visit(E->getRHS()); 1051 1052 if (LHS->getType()->isFPOrFPVector()) { 1053 Result = Builder.CreateVFCmp((llvm::CmpInst::Predicate)FCmpOpc, 1054 LHS, RHS, "cmp"); 1055 } else if (LHSTy->isUnsignedIntegerType()) { 1056 Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)UICmpOpc, 1057 LHS, RHS, "cmp"); 1058 } else { 1059 // Signed integers and pointers. 1060 Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)SICmpOpc, 1061 LHS, RHS, "cmp"); 1062 } 1063 return Result; 1064 } else { 1065 // Complex Comparison: can only be an equality comparison. 1066 CodeGenFunction::ComplexPairTy LHS = CGF.EmitComplexExpr(E->getLHS()); 1067 CodeGenFunction::ComplexPairTy RHS = CGF.EmitComplexExpr(E->getRHS()); 1068 1069 QualType CETy = LHSTy->getAsComplexType()->getElementType(); 1070 1071 Value *ResultR, *ResultI; 1072 if (CETy->isRealFloatingType()) { 1073 ResultR = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc, 1074 LHS.first, RHS.first, "cmp.r"); 1075 ResultI = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc, 1076 LHS.second, RHS.second, "cmp.i"); 1077 } else { 1078 // Complex comparisons can only be equality comparisons. As such, signed 1079 // and unsigned opcodes are the same. 1080 ResultR = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1081 LHS.first, RHS.first, "cmp.r"); 1082 ResultI = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1083 LHS.second, RHS.second, "cmp.i"); 1084 } 1085 1086 if (E->getOpcode() == BinaryOperator::EQ) { 1087 Result = Builder.CreateAnd(ResultR, ResultI, "and.ri"); 1088 } else { 1089 assert(E->getOpcode() == BinaryOperator::NE && 1090 "Complex comparison other than == or != ?"); 1091 Result = Builder.CreateOr(ResultR, ResultI, "or.ri"); 1092 } 1093 } 1094 1095 return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType()); 1096} 1097 1098Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) { 1099 LValue LHS = EmitLValue(E->getLHS()); 1100 Value *RHS = Visit(E->getRHS()); 1101 1102 // Store the value into the LHS. Bit-fields are handled specially 1103 // because the result is altered by the store, i.e., [C99 6.5.16p1] 1104 // 'An assignment expression has the value of the left operand after 1105 // the assignment...'. 1106 // FIXME: Volatility! 1107 if (LHS.isBitfield()) 1108 CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, E->getType(), 1109 &RHS); 1110 else 1111 CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS, E->getType()); 1112 1113 // Return the RHS. 1114 return RHS; 1115} 1116 1117Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) { 1118 // If we have 0 && RHS, see if we can elide RHS, if so, just return 0. 1119 // If we have 1 && X, just emit X without inserting the control flow. 1120 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) { 1121 if (Cond == 1) { // If we have 1 && X, just emit X. 1122 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1123 // ZExt result to int. 1124 return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "land.ext"); 1125 } 1126 1127 // 0 && RHS: If it is safe, just elide the RHS, and return 0. 1128 if (!CGF.ContainsLabel(E->getRHS())) 1129 return llvm::Constant::getNullValue(CGF.LLVMIntTy); 1130 } 1131 1132 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("land.end"); 1133 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("land.rhs"); 1134 1135 // Branch on the LHS first. If it is false, go to the failure (cont) block. 1136 CGF.EmitBranchOnBoolExpr(E->getLHS(), RHSBlock, ContBlock); 1137 1138 // Any edges into the ContBlock are now from an (indeterminate number of) 1139 // edges from this first condition. All of these values will be false. Start 1140 // setting up the PHI node in the Cont Block for this. 1141 llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::Int1Ty, "", ContBlock); 1142 PN->reserveOperandSpace(2); // Normal case, two inputs. 1143 for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); 1144 PI != PE; ++PI) 1145 PN->addIncoming(llvm::ConstantInt::getFalse(), *PI); 1146 1147 CGF.EmitBlock(RHSBlock); 1148 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1149 1150 // Reaquire the RHS block, as there may be subblocks inserted. 1151 RHSBlock = Builder.GetInsertBlock(); 1152 1153 // Emit an unconditional branch from this block to ContBlock. Insert an entry 1154 // into the phi node for the edge with the value of RHSCond. 1155 CGF.EmitBlock(ContBlock); 1156 PN->addIncoming(RHSCond, RHSBlock); 1157 1158 // ZExt result to int. 1159 return Builder.CreateZExt(PN, CGF.LLVMIntTy, "land.ext"); 1160} 1161 1162Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) { 1163 // If we have 1 || RHS, see if we can elide RHS, if so, just return 1. 1164 // If we have 0 || X, just emit X without inserting the control flow. 1165 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) { 1166 if (Cond == -1) { // If we have 0 || X, just emit X. 1167 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1168 // ZExt result to int. 1169 return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "lor.ext"); 1170 } 1171 1172 // 1 || RHS: If it is safe, just elide the RHS, and return 1. 1173 if (!CGF.ContainsLabel(E->getRHS())) 1174 return llvm::ConstantInt::get(CGF.LLVMIntTy, 1); 1175 } 1176 1177 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("lor.end"); 1178 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("lor.rhs"); 1179 1180 // Branch on the LHS first. If it is true, go to the success (cont) block. 1181 CGF.EmitBranchOnBoolExpr(E->getLHS(), ContBlock, RHSBlock); 1182 1183 // Any edges into the ContBlock are now from an (indeterminate number of) 1184 // edges from this first condition. All of these values will be true. Start 1185 // setting up the PHI node in the Cont Block for this. 1186 llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::Int1Ty, "", ContBlock); 1187 PN->reserveOperandSpace(2); // Normal case, two inputs. 1188 for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); 1189 PI != PE; ++PI) 1190 PN->addIncoming(llvm::ConstantInt::getTrue(), *PI); 1191 1192 // Emit the RHS condition as a bool value. 1193 CGF.EmitBlock(RHSBlock); 1194 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1195 1196 // Reaquire the RHS block, as there may be subblocks inserted. 1197 RHSBlock = Builder.GetInsertBlock(); 1198 1199 // Emit an unconditional branch from this block to ContBlock. Insert an entry 1200 // into the phi node for the edge with the value of RHSCond. 1201 CGF.EmitBlock(ContBlock); 1202 PN->addIncoming(RHSCond, RHSBlock); 1203 1204 // ZExt result to int. 1205 return Builder.CreateZExt(PN, CGF.LLVMIntTy, "lor.ext"); 1206} 1207 1208Value *ScalarExprEmitter::VisitBinComma(const BinaryOperator *E) { 1209 CGF.EmitStmt(E->getLHS()); 1210 CGF.EnsureInsertPoint(); 1211 return Visit(E->getRHS()); 1212} 1213 1214//===----------------------------------------------------------------------===// 1215// Other Operators 1216//===----------------------------------------------------------------------===// 1217 1218/// isCheapEnoughToEvaluateUnconditionally - Return true if the specified 1219/// expression is cheap enough and side-effect-free enough to evaluate 1220/// unconditionally instead of conditionally. This is used to convert control 1221/// flow into selects in some cases. 1222static bool isCheapEnoughToEvaluateUnconditionally(const Expr *E) { 1223 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) 1224 return isCheapEnoughToEvaluateUnconditionally(PE->getSubExpr()); 1225 1226 // TODO: Allow anything we can constant fold to an integer or fp constant. 1227 if (isa<IntegerLiteral>(E) || isa<CharacterLiteral>(E) || 1228 isa<FloatingLiteral>(E)) 1229 return true; 1230 1231 // Non-volatile automatic variables too, to get "cond ? X : Y" where 1232 // X and Y are local variables. 1233 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 1234 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) 1235 if (VD->hasLocalStorage() && !VD->getType().isVolatileQualified()) 1236 return true; 1237 1238 return false; 1239} 1240 1241 1242Value *ScalarExprEmitter:: 1243VisitConditionalOperator(const ConditionalOperator *E) { 1244 // If the condition constant folds and can be elided, try to avoid emitting 1245 // the condition and the dead arm. 1246 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getCond())){ 1247 Expr *Live = E->getLHS(), *Dead = E->getRHS(); 1248 if (Cond == -1) 1249 std::swap(Live, Dead); 1250 1251 // If the dead side doesn't have labels we need, and if the Live side isn't 1252 // the gnu missing ?: extension (which we could handle, but don't bother 1253 // to), just emit the Live part. 1254 if ((!Dead || !CGF.ContainsLabel(Dead)) && // No labels in dead part 1255 Live) // Live part isn't missing. 1256 return Visit(Live); 1257 } 1258 1259 1260 // If this is a really simple expression (like x ? 4 : 5), emit this as a 1261 // select instead of as control flow. We can only do this if it is cheap and 1262 // safe to evaluate the LHS and RHS unconditionally. 1263 if (E->getLHS() && isCheapEnoughToEvaluateUnconditionally(E->getLHS()) && 1264 isCheapEnoughToEvaluateUnconditionally(E->getRHS())) { 1265 llvm::Value *CondV = CGF.EvaluateExprAsBool(E->getCond()); 1266 llvm::Value *LHS = Visit(E->getLHS()); 1267 llvm::Value *RHS = Visit(E->getRHS()); 1268 return Builder.CreateSelect(CondV, LHS, RHS, "cond"); 1269 } 1270 1271 1272 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true"); 1273 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false"); 1274 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end"); 1275 Value *CondVal = 0; 1276 1277 // If we have the GNU missing condition extension, evaluate the conditional 1278 // and then convert it to bool the hard way. We do this explicitly 1279 // because we need the unconverted value for the missing middle value of 1280 // the ?:. 1281 if (E->getLHS() == 0) { 1282 CondVal = CGF.EmitScalarExpr(E->getCond()); 1283 Value *CondBoolVal = 1284 CGF.EmitScalarConversion(CondVal, E->getCond()->getType(), 1285 CGF.getContext().BoolTy); 1286 Builder.CreateCondBr(CondBoolVal, LHSBlock, RHSBlock); 1287 } else { 1288 // Otherwise, just use EmitBranchOnBoolExpr to get small and simple code for 1289 // the branch on bool. 1290 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock); 1291 } 1292 1293 CGF.EmitBlock(LHSBlock); 1294 1295 // Handle the GNU extension for missing LHS. 1296 Value *LHS; 1297 if (E->getLHS()) 1298 LHS = Visit(E->getLHS()); 1299 else // Perform promotions, to handle cases like "short ?: int" 1300 LHS = EmitScalarConversion(CondVal, E->getCond()->getType(), E->getType()); 1301 1302 LHSBlock = Builder.GetInsertBlock(); 1303 CGF.EmitBranch(ContBlock); 1304 1305 CGF.EmitBlock(RHSBlock); 1306 1307 Value *RHS = Visit(E->getRHS()); 1308 RHSBlock = Builder.GetInsertBlock(); 1309 CGF.EmitBranch(ContBlock); 1310 1311 CGF.EmitBlock(ContBlock); 1312 1313 if (!LHS || !RHS) { 1314 assert(E->getType()->isVoidType() && "Non-void value should have a value"); 1315 return 0; 1316 } 1317 1318 // Create a PHI node for the real part. 1319 llvm::PHINode *PN = Builder.CreatePHI(LHS->getType(), "cond"); 1320 PN->reserveOperandSpace(2); 1321 PN->addIncoming(LHS, LHSBlock); 1322 PN->addIncoming(RHS, RHSBlock); 1323 return PN; 1324} 1325 1326Value *ScalarExprEmitter::VisitChooseExpr(ChooseExpr *E) { 1327 // Emit the LHS or RHS as appropriate. 1328 return 1329 Visit(E->isConditionTrue(CGF.getContext()) ? E->getLHS() : E->getRHS()); 1330} 1331 1332Value *ScalarExprEmitter::VisitOverloadExpr(OverloadExpr *E) { 1333 return CGF.EmitCallExpr(E->getFn(), E->arg_begin(), 1334 E->arg_end(CGF.getContext())).getScalarVal(); 1335} 1336 1337Value *ScalarExprEmitter::VisitVAArgExpr(VAArgExpr *VE) { 1338 llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr()); 1339 llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType()); 1340 1341 // If EmitVAArg fails, we fall back to the LLVM instruction. 1342 if (!ArgPtr) 1343 return Builder.CreateVAArg(ArgValue, ConvertType(VE->getType())); 1344 1345 // FIXME: volatile? 1346 return Builder.CreateLoad(ArgPtr); 1347} 1348 1349Value *ScalarExprEmitter::VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { 1350 std::string str; 1351 CGF.getContext().getObjCEncodingForType(E->getEncodedType(), str); 1352 1353 llvm::Constant *C = llvm::ConstantArray::get(str); 1354 C = new llvm::GlobalVariable(C->getType(), true, 1355 llvm::GlobalValue::InternalLinkage, 1356 C, ".str", &CGF.CGM.getModule()); 1357 llvm::Constant *Zero = llvm::Constant::getNullValue(llvm::Type::Int32Ty); 1358 llvm::Constant *Zeros[] = { Zero, Zero }; 1359 C = llvm::ConstantExpr::getGetElementPtr(C, Zeros, 2); 1360 1361 return C; 1362} 1363 1364//===----------------------------------------------------------------------===// 1365// Entry Point into this File 1366//===----------------------------------------------------------------------===// 1367 1368/// EmitComplexExpr - Emit the computation of the specified expression of 1369/// complex type, ignoring the result. 1370Value *CodeGenFunction::EmitScalarExpr(const Expr *E) { 1371 assert(E && !hasAggregateLLVMType(E->getType()) && 1372 "Invalid scalar expression to emit"); 1373 1374 return ScalarExprEmitter(*this).Visit(const_cast<Expr*>(E)); 1375} 1376 1377/// EmitScalarConversion - Emit a conversion from the specified type to the 1378/// specified destination type, both of which are LLVM scalar types. 1379Value *CodeGenFunction::EmitScalarConversion(Value *Src, QualType SrcTy, 1380 QualType DstTy) { 1381 assert(!hasAggregateLLVMType(SrcTy) && !hasAggregateLLVMType(DstTy) && 1382 "Invalid scalar expression to emit"); 1383 return ScalarExprEmitter(*this).EmitScalarConversion(Src, SrcTy, DstTy); 1384} 1385 1386/// EmitComplexToScalarConversion - Emit a conversion from the specified 1387/// complex type to the specified destination type, where the destination 1388/// type is an LLVM scalar type. 1389Value *CodeGenFunction::EmitComplexToScalarConversion(ComplexPairTy Src, 1390 QualType SrcTy, 1391 QualType DstTy) { 1392 assert(SrcTy->isAnyComplexType() && !hasAggregateLLVMType(DstTy) && 1393 "Invalid complex -> scalar conversion"); 1394 return ScalarExprEmitter(*this).EmitComplexToScalarConversion(Src, SrcTy, 1395 DstTy); 1396} 1397 1398Value *CodeGenFunction::EmitShuffleVector(Value* V1, Value *V2, ...) { 1399 assert(V1->getType() == V2->getType() && 1400 "Vector operands must be of the same type"); 1401 unsigned NumElements = 1402 cast<llvm::VectorType>(V1->getType())->getNumElements(); 1403 1404 va_list va; 1405 va_start(va, V2); 1406 1407 llvm::SmallVector<llvm::Constant*, 16> Args; 1408 for (unsigned i = 0; i < NumElements; i++) { 1409 int n = va_arg(va, int); 1410 assert(n >= 0 && n < (int)NumElements * 2 && 1411 "Vector shuffle index out of bounds!"); 1412 Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, n)); 1413 } 1414 1415 const char *Name = va_arg(va, const char *); 1416 va_end(va); 1417 1418 llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements); 1419 1420 return Builder.CreateShuffleVector(V1, V2, Mask, Name); 1421} 1422 1423llvm::Value *CodeGenFunction::EmitVector(llvm::Value * const *Vals, 1424 unsigned NumVals, bool isSplat) { 1425 llvm::Value *Vec 1426 = llvm::UndefValue::get(llvm::VectorType::get(Vals[0]->getType(), NumVals)); 1427 1428 for (unsigned i = 0, e = NumVals; i != e; ++i) { 1429 llvm::Value *Val = isSplat ? Vals[0] : Vals[i]; 1430 llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 1431 Vec = Builder.CreateInsertElement(Vec, Val, Idx, "tmp"); 1432 } 1433 1434 return Vec; 1435} 1436