CGExprScalar.cpp revision 3498bdb9e9cb300de74c7b51c92608e2902b2348
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 const llvm::VectorType *VType = 173 dyn_cast<llvm::VectorType>(ConvertType(E->getType())); 174 175 // We have a scalar in braces. Just use the first element. 176 if (!VType) 177 return Visit(E->getInit(0)); 178 179 unsigned NumVectorElements = VType->getNumElements(); 180 const llvm::Type *ElementType = VType->getElementType(); 181 182 // Emit individual vector element stores. 183 llvm::Value *V = llvm::UndefValue::get(VType); 184 185 // Emit initializers 186 unsigned i; 187 for (i = 0; i < NumInitElements; ++i) { 188 Value *NewV = Visit(E->getInit(i)); 189 Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 190 V = Builder.CreateInsertElement(V, NewV, Idx); 191 } 192 193 // Emit remaining default initializers 194 for (/* Do not initialize i*/; i < NumVectorElements; ++i) { 195 Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 196 llvm::Value *NewV = llvm::Constant::getNullValue(ElementType); 197 V = Builder.CreateInsertElement(V, NewV, Idx); 198 } 199 200 return V; 201 } 202 203 Value *VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) { 204 return llvm::Constant::getNullValue(ConvertType(E->getType())); 205 } 206 Value *VisitImplicitCastExpr(const ImplicitCastExpr *E); 207 Value *VisitCastExpr(const CastExpr *E) { 208 return EmitCastExpr(E->getSubExpr(), E->getType()); 209 } 210 Value *EmitCastExpr(const Expr *E, QualType T); 211 212 Value *VisitCallExpr(const CallExpr *E) { 213 return CGF.EmitCallExpr(E).getScalarVal(); 214 } 215 216 Value *VisitStmtExpr(const StmtExpr *E); 217 218 // Unary Operators. 219 Value *VisitPrePostIncDec(const UnaryOperator *E, bool isInc, bool isPre); 220 Value *VisitUnaryPostDec(const UnaryOperator *E) { 221 return VisitPrePostIncDec(E, false, false); 222 } 223 Value *VisitUnaryPostInc(const UnaryOperator *E) { 224 return VisitPrePostIncDec(E, true, false); 225 } 226 Value *VisitUnaryPreDec(const UnaryOperator *E) { 227 return VisitPrePostIncDec(E, false, true); 228 } 229 Value *VisitUnaryPreInc(const UnaryOperator *E) { 230 return VisitPrePostIncDec(E, true, true); 231 } 232 Value *VisitUnaryAddrOf(const UnaryOperator *E) { 233 return EmitLValue(E->getSubExpr()).getAddress(); 234 } 235 Value *VisitUnaryDeref(const Expr *E) { return EmitLoadOfLValue(E); } 236 Value *VisitUnaryPlus(const UnaryOperator *E) { 237 return Visit(E->getSubExpr()); 238 } 239 Value *VisitUnaryMinus (const UnaryOperator *E); 240 Value *VisitUnaryNot (const UnaryOperator *E); 241 Value *VisitUnaryLNot (const UnaryOperator *E); 242 Value *VisitUnaryReal (const UnaryOperator *E); 243 Value *VisitUnaryImag (const UnaryOperator *E); 244 Value *VisitUnaryExtension(const UnaryOperator *E) { 245 return Visit(E->getSubExpr()); 246 } 247 Value *VisitUnaryOffsetOf(const UnaryOperator *E); 248 Value *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) { 249 return Visit(DAE->getExpr()); 250 } 251 252 // Binary Operators. 253 Value *EmitMul(const BinOpInfo &Ops) { 254 return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul"); 255 } 256 Value *EmitDiv(const BinOpInfo &Ops); 257 Value *EmitRem(const BinOpInfo &Ops); 258 Value *EmitAdd(const BinOpInfo &Ops); 259 Value *EmitSub(const BinOpInfo &Ops); 260 Value *EmitShl(const BinOpInfo &Ops); 261 Value *EmitShr(const BinOpInfo &Ops); 262 Value *EmitAnd(const BinOpInfo &Ops) { 263 return Builder.CreateAnd(Ops.LHS, Ops.RHS, "and"); 264 } 265 Value *EmitXor(const BinOpInfo &Ops) { 266 return Builder.CreateXor(Ops.LHS, Ops.RHS, "xor"); 267 } 268 Value *EmitOr (const BinOpInfo &Ops) { 269 return Builder.CreateOr(Ops.LHS, Ops.RHS, "or"); 270 } 271 272 BinOpInfo EmitBinOps(const BinaryOperator *E); 273 Value *EmitCompoundAssign(const CompoundAssignOperator *E, 274 Value *(ScalarExprEmitter::*F)(const BinOpInfo &)); 275 276 // Binary operators and binary compound assignment operators. 277#define HANDLEBINOP(OP) \ 278 Value *VisitBin ## OP(const BinaryOperator *E) { \ 279 return Emit ## OP(EmitBinOps(E)); \ 280 } \ 281 Value *VisitBin ## OP ## Assign(const CompoundAssignOperator *E) { \ 282 return EmitCompoundAssign(E, &ScalarExprEmitter::Emit ## OP); \ 283 } 284 HANDLEBINOP(Mul); 285 HANDLEBINOP(Div); 286 HANDLEBINOP(Rem); 287 HANDLEBINOP(Add); 288 HANDLEBINOP(Sub); 289 HANDLEBINOP(Shl); 290 HANDLEBINOP(Shr); 291 HANDLEBINOP(And); 292 HANDLEBINOP(Xor); 293 HANDLEBINOP(Or); 294#undef HANDLEBINOP 295 296 // Comparisons. 297 Value *EmitCompare(const BinaryOperator *E, unsigned UICmpOpc, 298 unsigned SICmpOpc, unsigned FCmpOpc); 299#define VISITCOMP(CODE, UI, SI, FP) \ 300 Value *VisitBin##CODE(const BinaryOperator *E) { \ 301 return EmitCompare(E, llvm::ICmpInst::UI, llvm::ICmpInst::SI, \ 302 llvm::FCmpInst::FP); } 303 VISITCOMP(LT, ICMP_ULT, ICMP_SLT, FCMP_OLT); 304 VISITCOMP(GT, ICMP_UGT, ICMP_SGT, FCMP_OGT); 305 VISITCOMP(LE, ICMP_ULE, ICMP_SLE, FCMP_OLE); 306 VISITCOMP(GE, ICMP_UGE, ICMP_SGE, FCMP_OGE); 307 VISITCOMP(EQ, ICMP_EQ , ICMP_EQ , FCMP_OEQ); 308 VISITCOMP(NE, ICMP_NE , ICMP_NE , FCMP_UNE); 309#undef VISITCOMP 310 311 Value *VisitBinAssign (const BinaryOperator *E); 312 313 Value *VisitBinLAnd (const BinaryOperator *E); 314 Value *VisitBinLOr (const BinaryOperator *E); 315 Value *VisitBinComma (const BinaryOperator *E); 316 317 // Other Operators. 318 Value *VisitBlockExpr(const BlockExpr *BE) { 319 CGF.ErrorUnsupported(BE, "block expression"); 320 return llvm::UndefValue::get(CGF.ConvertType(BE->getType())); 321 } 322 323 Value *VisitConditionalOperator(const ConditionalOperator *CO); 324 Value *VisitChooseExpr(ChooseExpr *CE); 325 Value *VisitOverloadExpr(OverloadExpr *OE); 326 Value *VisitVAArgExpr(VAArgExpr *VE); 327 Value *VisitObjCStringLiteral(const ObjCStringLiteral *E) { 328 return CGF.EmitObjCStringLiteral(E); 329 } 330 Value *VisitObjCEncodeExpr(const ObjCEncodeExpr *E); 331}; 332} // end anonymous namespace. 333 334//===----------------------------------------------------------------------===// 335// Utilities 336//===----------------------------------------------------------------------===// 337 338/// EmitConversionToBool - Convert the specified expression value to a 339/// boolean (i1) truth value. This is equivalent to "Val != 0". 340Value *ScalarExprEmitter::EmitConversionToBool(Value *Src, QualType SrcType) { 341 assert(SrcType->isCanonical() && "EmitScalarConversion strips typedefs"); 342 343 if (SrcType->isRealFloatingType()) { 344 // Compare against 0.0 for fp scalars. 345 llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType()); 346 return Builder.CreateFCmpUNE(Src, Zero, "tobool"); 347 } 348 349 assert((SrcType->isIntegerType() || isa<llvm::PointerType>(Src->getType())) && 350 "Unknown scalar type to convert"); 351 352 // Because of the type rules of C, we often end up computing a logical value, 353 // then zero extending it to int, then wanting it as a logical value again. 354 // Optimize this common case. 355 if (llvm::ZExtInst *ZI = dyn_cast<llvm::ZExtInst>(Src)) { 356 if (ZI->getOperand(0)->getType() == llvm::Type::Int1Ty) { 357 Value *Result = ZI->getOperand(0); 358 // If there aren't any more uses, zap the instruction to save space. 359 // Note that there can be more uses, for example if this 360 // is the result of an assignment. 361 if (ZI->use_empty()) 362 ZI->eraseFromParent(); 363 return Result; 364 } 365 } 366 367 // Compare against an integer or pointer null. 368 llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType()); 369 return Builder.CreateICmpNE(Src, Zero, "tobool"); 370} 371 372/// EmitScalarConversion - Emit a conversion from the specified type to the 373/// specified destination type, both of which are LLVM scalar types. 374Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType, 375 QualType DstType) { 376 SrcType = CGF.getContext().getCanonicalType(SrcType); 377 DstType = CGF.getContext().getCanonicalType(DstType); 378 if (SrcType == DstType) return Src; 379 380 if (DstType->isVoidType()) return 0; 381 382 // Handle conversions to bool first, they are special: comparisons against 0. 383 if (DstType->isBooleanType()) 384 return EmitConversionToBool(Src, SrcType); 385 386 const llvm::Type *DstTy = ConvertType(DstType); 387 388 // Ignore conversions like int -> uint. 389 if (Src->getType() == DstTy) 390 return Src; 391 392 // Handle pointer conversions next: pointers can only be converted 393 // to/from other pointers and integers. Check for pointer types in 394 // terms of LLVM, as some native types (like Obj-C id) may map to a 395 // pointer type. 396 if (isa<llvm::PointerType>(DstTy)) { 397 // The source value may be an integer, or a pointer. 398 if (isa<llvm::PointerType>(Src->getType())) 399 return Builder.CreateBitCast(Src, DstTy, "conv"); 400 assert(SrcType->isIntegerType() && "Not ptr->ptr or int->ptr conversion?"); 401 return Builder.CreateIntToPtr(Src, DstTy, "conv"); 402 } 403 404 if (isa<llvm::PointerType>(Src->getType())) { 405 // Must be an ptr to int cast. 406 assert(isa<llvm::IntegerType>(DstTy) && "not ptr->int?"); 407 return Builder.CreatePtrToInt(Src, DstTy, "conv"); 408 } 409 410 // A scalar can be splatted to an extended vector of the same element type 411 if (DstType->isExtVectorType() && !isa<VectorType>(SrcType)) { 412 // Cast the scalar to element type 413 QualType EltTy = DstType->getAsExtVectorType()->getElementType(); 414 llvm::Value *Elt = EmitScalarConversion(Src, SrcType, EltTy); 415 416 // Insert the element in element zero of an undef vector 417 llvm::Value *UnV = llvm::UndefValue::get(DstTy); 418 llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, 0); 419 UnV = Builder.CreateInsertElement(UnV, Elt, Idx, "tmp"); 420 421 // Splat the element across to all elements 422 llvm::SmallVector<llvm::Constant*, 16> Args; 423 unsigned NumElements = cast<llvm::VectorType>(DstTy)->getNumElements(); 424 for (unsigned i = 0; i < NumElements; i++) 425 Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0)); 426 427 llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements); 428 llvm::Value *Yay = Builder.CreateShuffleVector(UnV, UnV, Mask, "splat"); 429 return Yay; 430 } 431 432 // Allow bitcast from vector to integer/fp of the same size. 433 if (isa<llvm::VectorType>(Src->getType()) || 434 isa<llvm::VectorType>(DstTy)) 435 return Builder.CreateBitCast(Src, DstTy, "conv"); 436 437 // Finally, we have the arithmetic types: real int/float. 438 if (isa<llvm::IntegerType>(Src->getType())) { 439 bool InputSigned = SrcType->isSignedIntegerType(); 440 if (isa<llvm::IntegerType>(DstTy)) 441 return Builder.CreateIntCast(Src, DstTy, InputSigned, "conv"); 442 else if (InputSigned) 443 return Builder.CreateSIToFP(Src, DstTy, "conv"); 444 else 445 return Builder.CreateUIToFP(Src, DstTy, "conv"); 446 } 447 448 assert(Src->getType()->isFloatingPoint() && "Unknown real conversion"); 449 if (isa<llvm::IntegerType>(DstTy)) { 450 if (DstType->isSignedIntegerType()) 451 return Builder.CreateFPToSI(Src, DstTy, "conv"); 452 else 453 return Builder.CreateFPToUI(Src, DstTy, "conv"); 454 } 455 456 assert(DstTy->isFloatingPoint() && "Unknown real conversion"); 457 if (DstTy->getTypeID() < Src->getType()->getTypeID()) 458 return Builder.CreateFPTrunc(Src, DstTy, "conv"); 459 else 460 return Builder.CreateFPExt(Src, DstTy, "conv"); 461} 462 463/// EmitComplexToScalarConversion - Emit a conversion from the specified 464/// complex type to the specified destination type, where the destination 465/// type is an LLVM scalar type. 466Value *ScalarExprEmitter:: 467EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src, 468 QualType SrcTy, QualType DstTy) { 469 // Get the source element type. 470 SrcTy = SrcTy->getAsComplexType()->getElementType(); 471 472 // Handle conversions to bool first, they are special: comparisons against 0. 473 if (DstTy->isBooleanType()) { 474 // Complex != 0 -> (Real != 0) | (Imag != 0) 475 Src.first = EmitScalarConversion(Src.first, SrcTy, DstTy); 476 Src.second = EmitScalarConversion(Src.second, SrcTy, DstTy); 477 return Builder.CreateOr(Src.first, Src.second, "tobool"); 478 } 479 480 // C99 6.3.1.7p2: "When a value of complex type is converted to a real type, 481 // the imaginary part of the complex value is discarded and the value of the 482 // real part is converted according to the conversion rules for the 483 // corresponding real type. 484 return EmitScalarConversion(Src.first, SrcTy, DstTy); 485} 486 487 488//===----------------------------------------------------------------------===// 489// Visitor Methods 490//===----------------------------------------------------------------------===// 491 492Value *ScalarExprEmitter::VisitExpr(Expr *E) { 493 CGF.ErrorUnsupported(E, "scalar expression"); 494 if (E->getType()->isVoidType()) 495 return 0; 496 return llvm::UndefValue::get(CGF.ConvertType(E->getType())); 497} 498 499Value *ScalarExprEmitter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) { 500 llvm::SmallVector<llvm::Constant*, 32> indices; 501 for (unsigned i = 2; i < E->getNumSubExprs(); i++) { 502 indices.push_back(cast<llvm::Constant>(CGF.EmitScalarExpr(E->getExpr(i)))); 503 } 504 Value* V1 = CGF.EmitScalarExpr(E->getExpr(0)); 505 Value* V2 = CGF.EmitScalarExpr(E->getExpr(1)); 506 Value* SV = llvm::ConstantVector::get(indices.begin(), indices.size()); 507 return Builder.CreateShuffleVector(V1, V2, SV, "shuffle"); 508} 509 510Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) { 511 // Emit subscript expressions in rvalue context's. For most cases, this just 512 // loads the lvalue formed by the subscript expr. However, we have to be 513 // careful, because the base of a vector subscript is occasionally an rvalue, 514 // so we can't get it as an lvalue. 515 if (!E->getBase()->getType()->isVectorType()) 516 return EmitLoadOfLValue(E); 517 518 // Handle the vector case. The base must be a vector, the index must be an 519 // integer value. 520 Value *Base = Visit(E->getBase()); 521 Value *Idx = Visit(E->getIdx()); 522 523 // FIXME: Convert Idx to i32 type. 524 return Builder.CreateExtractElement(Base, Idx, "vecext"); 525} 526 527/// VisitImplicitCastExpr - Implicit casts are the same as normal casts, but 528/// also handle things like function to pointer-to-function decay, and array to 529/// pointer decay. 530Value *ScalarExprEmitter::VisitImplicitCastExpr(const ImplicitCastExpr *E) { 531 const Expr *Op = E->getSubExpr(); 532 533 // If this is due to array->pointer conversion, emit the array expression as 534 // an l-value. 535 if (Op->getType()->isArrayType()) { 536 // FIXME: For now we assume that all source arrays map to LLVM arrays. This 537 // will not true when we add support for VLAs. 538 Value *V = EmitLValue(Op).getAddress(); // Bitfields can't be arrays. 539 540 if (!Op->getType()->isVariableArrayType()) { 541 assert(isa<llvm::PointerType>(V->getType()) && "Expected pointer"); 542 assert(isa<llvm::ArrayType>(cast<llvm::PointerType>(V->getType()) 543 ->getElementType()) && 544 "Expected pointer to array"); 545 V = Builder.CreateStructGEP(V, 0, "arraydecay"); 546 } 547 548 // The resultant pointer type can be implicitly casted to other pointer 549 // types as well (e.g. void*) and can be implicitly converted to integer. 550 const llvm::Type *DestTy = ConvertType(E->getType()); 551 if (V->getType() != DestTy) { 552 if (isa<llvm::PointerType>(DestTy)) 553 V = Builder.CreateBitCast(V, DestTy, "ptrconv"); 554 else { 555 assert(isa<llvm::IntegerType>(DestTy) && "Unknown array decay"); 556 V = Builder.CreatePtrToInt(V, DestTy, "ptrconv"); 557 } 558 } 559 return V; 560 561 } else if (E->getType()->isReferenceType()) { 562 return EmitLValue(Op).getAddress(); 563 } 564 565 return EmitCastExpr(Op, E->getType()); 566} 567 568 569// VisitCastExpr - Emit code for an explicit or implicit cast. Implicit casts 570// have to handle a more broad range of conversions than explicit casts, as they 571// handle things like function to ptr-to-function decay etc. 572Value *ScalarExprEmitter::EmitCastExpr(const Expr *E, QualType DestTy) { 573 // Handle cases where the source is an non-complex type. 574 575 if (!CGF.hasAggregateLLVMType(E->getType())) { 576 Value *Src = Visit(const_cast<Expr*>(E)); 577 578 // Use EmitScalarConversion to perform the conversion. 579 return EmitScalarConversion(Src, E->getType(), DestTy); 580 } 581 582 if (E->getType()->isAnyComplexType()) { 583 // Handle cases where the source is a complex type. 584 return EmitComplexToScalarConversion(CGF.EmitComplexExpr(E), E->getType(), 585 DestTy); 586 } 587 588 // Okay, this is a cast from an aggregate. It must be a cast to void. Just 589 // evaluate the result and return. 590 CGF.EmitAggExpr(E, 0, false); 591 return 0; 592} 593 594Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) { 595 return CGF.EmitCompoundStmt(*E->getSubStmt(), 596 !E->getType()->isVoidType()).getScalarVal(); 597} 598 599 600//===----------------------------------------------------------------------===// 601// Unary Operators 602//===----------------------------------------------------------------------===// 603 604Value *ScalarExprEmitter::VisitPrePostIncDec(const UnaryOperator *E, 605 bool isInc, bool isPre) { 606 LValue LV = EmitLValue(E->getSubExpr()); 607 // FIXME: Handle volatile! 608 Value *InVal = CGF.EmitLoadOfLValue(LV, // false 609 E->getSubExpr()->getType()).getScalarVal(); 610 611 int AmountVal = isInc ? 1 : -1; 612 613 Value *NextVal; 614 if (isa<llvm::PointerType>(InVal->getType())) { 615 // FIXME: This isn't right for VLAs. 616 NextVal = llvm::ConstantInt::get(llvm::Type::Int32Ty, AmountVal); 617 NextVal = Builder.CreateGEP(InVal, NextVal, "ptrincdec"); 618 } else { 619 // Add the inc/dec to the real part. 620 if (isa<llvm::IntegerType>(InVal->getType())) 621 NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal); 622 else if (InVal->getType() == llvm::Type::FloatTy) 623 NextVal = 624 llvm::ConstantFP::get(llvm::APFloat(static_cast<float>(AmountVal))); 625 else if (InVal->getType() == llvm::Type::DoubleTy) 626 NextVal = 627 llvm::ConstantFP::get(llvm::APFloat(static_cast<double>(AmountVal))); 628 else { 629 llvm::APFloat F(static_cast<float>(AmountVal)); 630 bool ignored; 631 F.convert(CGF.Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero, 632 &ignored); 633 NextVal = llvm::ConstantFP::get(F); 634 } 635 NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec"); 636 } 637 638 // Store the updated result through the lvalue. 639 CGF.EmitStoreThroughLValue(RValue::get(NextVal), LV, 640 E->getSubExpr()->getType()); 641 642 // If this is a postinc, return the value read from memory, otherwise use the 643 // updated value. 644 return isPre ? NextVal : InVal; 645} 646 647 648Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) { 649 Value *Op = Visit(E->getSubExpr()); 650 return Builder.CreateNeg(Op, "neg"); 651} 652 653Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) { 654 Value *Op = Visit(E->getSubExpr()); 655 return Builder.CreateNot(Op, "neg"); 656} 657 658Value *ScalarExprEmitter::VisitUnaryLNot(const UnaryOperator *E) { 659 // Compare operand to zero. 660 Value *BoolVal = CGF.EvaluateExprAsBool(E->getSubExpr()); 661 662 // Invert value. 663 // TODO: Could dynamically modify easy computations here. For example, if 664 // the operand is an icmp ne, turn into icmp eq. 665 BoolVal = Builder.CreateNot(BoolVal, "lnot"); 666 667 // ZExt result to int. 668 return Builder.CreateZExt(BoolVal, CGF.LLVMIntTy, "lnot.ext"); 669} 670 671/// VisitSizeOfAlignOfExpr - Return the size or alignment of the type of 672/// argument of the sizeof expression as an integer. 673Value * 674ScalarExprEmitter::VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E) { 675 QualType TypeToSize = E->getTypeOfArgument(); 676 if (E->isSizeOf()) { 677 if (const VariableArrayType *VAT = 678 CGF.getContext().getAsVariableArrayType(TypeToSize)) { 679 if (E->isArgumentType()) { 680 // sizeof(type) - make sure to emit the VLA size. 681 CGF.EmitVLASize(TypeToSize); 682 } 683 return CGF.GetVLASize(VAT); 684 } 685 } 686 687 // If this isn't sizeof(vla), the result must be constant; use the 688 // constant folding logic so we don't have to duplicate it here. 689 Expr::EvalResult Result; 690 E->Evaluate(Result, CGF.getContext()); 691 return llvm::ConstantInt::get(Result.Val.getInt()); 692} 693 694Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E) { 695 Expr *Op = E->getSubExpr(); 696 if (Op->getType()->isAnyComplexType()) 697 return CGF.EmitComplexExpr(Op).first; 698 return Visit(Op); 699} 700Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E) { 701 Expr *Op = E->getSubExpr(); 702 if (Op->getType()->isAnyComplexType()) 703 return CGF.EmitComplexExpr(Op).second; 704 705 // __imag on a scalar returns zero. Emit it the subexpr to ensure side 706 // effects are evaluated. 707 CGF.EmitScalarExpr(Op); 708 return llvm::Constant::getNullValue(ConvertType(E->getType())); 709} 710 711Value *ScalarExprEmitter::VisitUnaryOffsetOf(const UnaryOperator *E) 712{ 713 const Expr* SubExpr = E->getSubExpr(); 714 const llvm::Type* ResultType = ConvertType(E->getType()); 715 llvm::Value* Result = llvm::Constant::getNullValue(ResultType); 716 while (!isa<CompoundLiteralExpr>(SubExpr)) { 717 if (const MemberExpr *ME = dyn_cast<MemberExpr>(SubExpr)) { 718 SubExpr = ME->getBase(); 719 QualType Ty = SubExpr->getType(); 720 721 RecordDecl *RD = Ty->getAsRecordType()->getDecl(); 722 const ASTRecordLayout &RL = CGF.getContext().getASTRecordLayout(RD); 723 FieldDecl *FD = cast<FieldDecl>(ME->getMemberDecl()); 724 725 // FIXME: This is linear time. And the fact that we're indexing 726 // into the layout by position in the record means that we're 727 // either stuck numbering the fields in the AST or we have to keep 728 // the linear search (yuck and yuck). 729 unsigned i = 0; 730 for (RecordDecl::field_iterator Field = RD->field_begin(), 731 FieldEnd = RD->field_end(); 732 Field != FieldEnd; (void)++Field, ++i) { 733 if (*Field == FD) 734 break; 735 } 736 737 llvm::Value* Offset = 738 llvm::ConstantInt::get(ResultType, RL.getFieldOffset(i) / 8); 739 Result = Builder.CreateAdd(Result, Offset); 740 } else if (const ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(SubExpr)) { 741 SubExpr = ASE->getBase(); 742 int64_t size = CGF.getContext().getTypeSize(ASE->getType()) / 8; 743 llvm::Value* ElemSize = llvm::ConstantInt::get(ResultType, size); 744 llvm::Value* ElemIndex = CGF.EmitScalarExpr(ASE->getIdx()); 745 bool IndexSigned = ASE->getIdx()->getType()->isSignedIntegerType(); 746 ElemIndex = Builder.CreateIntCast(ElemIndex, ResultType, IndexSigned); 747 llvm::Value* Offset = Builder.CreateMul(ElemSize, ElemIndex); 748 Result = Builder.CreateAdd(Result, Offset); 749 } else { 750 assert(0 && "This should be impossible!"); 751 } 752 } 753 return Result; 754} 755 756//===----------------------------------------------------------------------===// 757// Binary Operators 758//===----------------------------------------------------------------------===// 759 760BinOpInfo ScalarExprEmitter::EmitBinOps(const BinaryOperator *E) { 761 BinOpInfo Result; 762 Result.LHS = Visit(E->getLHS()); 763 Result.RHS = Visit(E->getRHS()); 764 Result.Ty = E->getType(); 765 Result.E = E; 766 return Result; 767} 768 769Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E, 770 Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) { 771 QualType LHSTy = E->getLHS()->getType(), RHSTy = E->getRHS()->getType(); 772 773 BinOpInfo OpInfo; 774 775 // Load the LHS and RHS operands. 776 LValue LHSLV = EmitLValue(E->getLHS()); 777 OpInfo.LHS = EmitLoadOfLValue(LHSLV, LHSTy); 778 779 // Determine the computation type. If the RHS is complex, then this is one of 780 // the add/sub/mul/div operators. All of these operators can be computed in 781 // with just their real component even though the computation domain really is 782 // complex. 783 QualType ComputeType = E->getComputationType(); 784 785 // If the computation type is complex, then the RHS is complex. Emit the RHS. 786 if (const ComplexType *CT = ComputeType->getAsComplexType()) { 787 ComputeType = CT->getElementType(); 788 789 // Emit the RHS, only keeping the real component. 790 OpInfo.RHS = CGF.EmitComplexExpr(E->getRHS()).first; 791 RHSTy = RHSTy->getAsComplexType()->getElementType(); 792 } else { 793 // Otherwise the RHS is a simple scalar value. 794 OpInfo.RHS = Visit(E->getRHS()); 795 } 796 797 QualType LComputeTy, RComputeTy, ResultTy; 798 799 // Compound assignment does not contain enough information about all 800 // the types involved for pointer arithmetic cases. Figure it out 801 // here for now. 802 if (E->getLHS()->getType()->isPointerType()) { 803 // Pointer arithmetic cases: ptr +=,-= int and ptr -= ptr, 804 assert((E->getOpcode() == BinaryOperator::AddAssign || 805 E->getOpcode() == BinaryOperator::SubAssign) && 806 "Invalid compound assignment operator on pointer type."); 807 LComputeTy = E->getLHS()->getType(); 808 809 if (E->getRHS()->getType()->isPointerType()) { 810 // Degenerate case of (ptr -= ptr) allowed by GCC implicit cast 811 // extension, the conversion from the pointer difference back to 812 // the LHS type is handled at the end. 813 assert(E->getOpcode() == BinaryOperator::SubAssign && 814 "Invalid compound assignment operator on pointer type."); 815 RComputeTy = E->getLHS()->getType(); 816 ResultTy = CGF.getContext().getPointerDiffType(); 817 } else { 818 RComputeTy = E->getRHS()->getType(); 819 ResultTy = LComputeTy; 820 } 821 } else if (E->getRHS()->getType()->isPointerType()) { 822 // Degenerate case of (int += ptr) allowed by GCC implicit cast 823 // extension. 824 assert(E->getOpcode() == BinaryOperator::AddAssign && 825 "Invalid compound assignment operator on pointer type."); 826 LComputeTy = E->getLHS()->getType(); 827 RComputeTy = E->getRHS()->getType(); 828 ResultTy = RComputeTy; 829 } else { 830 LComputeTy = RComputeTy = ResultTy = ComputeType; 831 } 832 833 // Convert the LHS/RHS values to the computation type. 834 OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy, LComputeTy); 835 OpInfo.RHS = EmitScalarConversion(OpInfo.RHS, RHSTy, RComputeTy); 836 OpInfo.Ty = ResultTy; 837 OpInfo.E = E; 838 839 // Expand the binary operator. 840 Value *Result = (this->*Func)(OpInfo); 841 842 // Convert the result back to the LHS type. 843 Result = EmitScalarConversion(Result, ResultTy, LHSTy); 844 845 // Store the result value into the LHS lvalue. Bit-fields are 846 // handled specially because the result is altered by the store, 847 // i.e., [C99 6.5.16p1] 'An assignment expression has the value of 848 // the left operand after the assignment...'. 849 if (LHSLV.isBitfield()) 850 CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, LHSTy, 851 &Result); 852 else 853 CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV, LHSTy); 854 855 return Result; 856} 857 858 859Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) { 860 if (Ops.LHS->getType()->isFPOrFPVector()) 861 return Builder.CreateFDiv(Ops.LHS, Ops.RHS, "div"); 862 else if (Ops.Ty->isUnsignedIntegerType()) 863 return Builder.CreateUDiv(Ops.LHS, Ops.RHS, "div"); 864 else 865 return Builder.CreateSDiv(Ops.LHS, Ops.RHS, "div"); 866} 867 868Value *ScalarExprEmitter::EmitRem(const BinOpInfo &Ops) { 869 // Rem in C can't be a floating point type: C99 6.5.5p2. 870 if (Ops.Ty->isUnsignedIntegerType()) 871 return Builder.CreateURem(Ops.LHS, Ops.RHS, "rem"); 872 else 873 return Builder.CreateSRem(Ops.LHS, Ops.RHS, "rem"); 874} 875 876 877Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &Ops) { 878 if (!Ops.Ty->isPointerType()) 879 return Builder.CreateAdd(Ops.LHS, Ops.RHS, "add"); 880 881 // FIXME: What about a pointer to a VLA? 882 Value *Ptr, *Idx; 883 Expr *IdxExp; 884 const PointerType *PT; 885 if ((PT = Ops.E->getLHS()->getType()->getAsPointerType())) { 886 Ptr = Ops.LHS; 887 Idx = Ops.RHS; 888 IdxExp = Ops.E->getRHS(); 889 } else { // int + pointer 890 PT = Ops.E->getRHS()->getType()->getAsPointerType(); 891 assert(PT && "Invalid add expr"); 892 Ptr = Ops.RHS; 893 Idx = Ops.LHS; 894 IdxExp = Ops.E->getLHS(); 895 } 896 897 unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth(); 898 if (Width < CGF.LLVMPointerWidth) { 899 // Zero or sign extend the pointer value based on whether the index is 900 // signed or not. 901 const llvm::Type *IdxType = llvm::IntegerType::get(CGF.LLVMPointerWidth); 902 if (IdxExp->getType()->isSignedIntegerType()) 903 Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext"); 904 else 905 Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext"); 906 } 907 908 // Explicitly handle GNU void* and function pointer arithmetic 909 // extensions. The GNU void* casts amount to no-ops since our void* 910 // type is i8*, but this is future proof. 911 const QualType ElementType = PT->getPointeeType(); 912 if (ElementType->isVoidType() || ElementType->isFunctionType()) { 913 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 914 Value *Casted = Builder.CreateBitCast(Ptr, i8Ty); 915 Value *Res = Builder.CreateGEP(Casted, Idx, "sub.ptr"); 916 return Builder.CreateBitCast(Res, Ptr->getType()); 917 } 918 919 return Builder.CreateGEP(Ptr, Idx, "add.ptr"); 920} 921 922Value *ScalarExprEmitter::EmitSub(const BinOpInfo &Ops) { 923 if (!isa<llvm::PointerType>(Ops.LHS->getType())) 924 return Builder.CreateSub(Ops.LHS, Ops.RHS, "sub"); 925 926 const QualType LHSType = Ops.E->getLHS()->getType(); 927 const QualType LHSElementType = LHSType->getAsPointerType()->getPointeeType(); 928 if (!isa<llvm::PointerType>(Ops.RHS->getType())) { 929 // pointer - int 930 Value *Idx = Ops.RHS; 931 unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth(); 932 if (Width < CGF.LLVMPointerWidth) { 933 // Zero or sign extend the pointer value based on whether the index is 934 // signed or not. 935 const llvm::Type *IdxType = llvm::IntegerType::get(CGF.LLVMPointerWidth); 936 if (Ops.E->getRHS()->getType()->isSignedIntegerType()) 937 Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext"); 938 else 939 Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext"); 940 } 941 Idx = Builder.CreateNeg(Idx, "sub.ptr.neg"); 942 943 // FIXME: The pointer could point to a VLA. 944 945 // Explicitly handle GNU void* and function pointer arithmetic 946 // extensions. The GNU void* casts amount to no-ops since our 947 // void* type is i8*, but this is future proof. 948 if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) { 949 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 950 Value *LHSCasted = Builder.CreateBitCast(Ops.LHS, i8Ty); 951 Value *Res = Builder.CreateGEP(LHSCasted, Idx, "sub.ptr"); 952 return Builder.CreateBitCast(Res, Ops.LHS->getType()); 953 } 954 955 return Builder.CreateGEP(Ops.LHS, Idx, "sub.ptr"); 956 } else { 957 // pointer - pointer 958 Value *LHS = Ops.LHS; 959 Value *RHS = Ops.RHS; 960 961 uint64_t ElementSize; 962 963 // Handle GCC extension for pointer arithmetic on void* types. 964 if (LHSElementType->isVoidType()) { 965 ElementSize = 1; 966 } else { 967 ElementSize = CGF.getContext().getTypeSize(LHSElementType) / 8; 968 } 969 970 const llvm::Type *ResultType = ConvertType(Ops.Ty); 971 LHS = Builder.CreatePtrToInt(LHS, ResultType, "sub.ptr.lhs.cast"); 972 RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast"); 973 Value *BytesBetween = Builder.CreateSub(LHS, RHS, "sub.ptr.sub"); 974 975 // HACK: LLVM doesn't have an divide instruction that 'knows' there is no 976 // remainder. As such, we handle common power-of-two cases here to generate 977 // better code. See PR2247. 978 if (llvm::isPowerOf2_64(ElementSize)) { 979 Value *ShAmt = 980 llvm::ConstantInt::get(ResultType, llvm::Log2_64(ElementSize)); 981 return Builder.CreateAShr(BytesBetween, ShAmt, "sub.ptr.shr"); 982 } 983 984 // Otherwise, do a full sdiv. 985 Value *BytesPerElt = llvm::ConstantInt::get(ResultType, ElementSize); 986 return Builder.CreateSDiv(BytesBetween, BytesPerElt, "sub.ptr.div"); 987 } 988} 989 990Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) { 991 // LLVM requires the LHS and RHS to be the same type: promote or truncate the 992 // RHS to the same size as the LHS. 993 Value *RHS = Ops.RHS; 994 if (Ops.LHS->getType() != RHS->getType()) 995 RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); 996 997 return Builder.CreateShl(Ops.LHS, RHS, "shl"); 998} 999 1000Value *ScalarExprEmitter::EmitShr(const BinOpInfo &Ops) { 1001 // LLVM requires the LHS and RHS to be the same type: promote or truncate the 1002 // RHS to the same size as the LHS. 1003 Value *RHS = Ops.RHS; 1004 if (Ops.LHS->getType() != RHS->getType()) 1005 RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); 1006 1007 if (Ops.Ty->isUnsignedIntegerType()) 1008 return Builder.CreateLShr(Ops.LHS, RHS, "shr"); 1009 return Builder.CreateAShr(Ops.LHS, RHS, "shr"); 1010} 1011 1012Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,unsigned UICmpOpc, 1013 unsigned SICmpOpc, unsigned FCmpOpc) { 1014 Value *Result; 1015 QualType LHSTy = E->getLHS()->getType(); 1016 if (!LHSTy->isAnyComplexType() && !LHSTy->isVectorType()) { 1017 Value *LHS = Visit(E->getLHS()); 1018 Value *RHS = Visit(E->getRHS()); 1019 1020 if (LHS->getType()->isFloatingPoint()) { 1021 Result = Builder.CreateFCmp((llvm::CmpInst::Predicate)FCmpOpc, 1022 LHS, RHS, "cmp"); 1023 } else if (LHSTy->isSignedIntegerType()) { 1024 Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)SICmpOpc, 1025 LHS, RHS, "cmp"); 1026 } else { 1027 // Unsigned integers and pointers. 1028 Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1029 LHS, RHS, "cmp"); 1030 } 1031 } else if (LHSTy->isVectorType()) { 1032 Value *LHS = Visit(E->getLHS()); 1033 Value *RHS = Visit(E->getRHS()); 1034 1035 if (LHS->getType()->isFPOrFPVector()) { 1036 Result = Builder.CreateVFCmp((llvm::CmpInst::Predicate)FCmpOpc, 1037 LHS, RHS, "cmp"); 1038 } else if (LHSTy->isUnsignedIntegerType()) { 1039 Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)UICmpOpc, 1040 LHS, RHS, "cmp"); 1041 } else { 1042 // Signed integers and pointers. 1043 Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)SICmpOpc, 1044 LHS, RHS, "cmp"); 1045 } 1046 return Result; 1047 } else { 1048 // Complex Comparison: can only be an equality comparison. 1049 CodeGenFunction::ComplexPairTy LHS = CGF.EmitComplexExpr(E->getLHS()); 1050 CodeGenFunction::ComplexPairTy RHS = CGF.EmitComplexExpr(E->getRHS()); 1051 1052 QualType CETy = LHSTy->getAsComplexType()->getElementType(); 1053 1054 Value *ResultR, *ResultI; 1055 if (CETy->isRealFloatingType()) { 1056 ResultR = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc, 1057 LHS.first, RHS.first, "cmp.r"); 1058 ResultI = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc, 1059 LHS.second, RHS.second, "cmp.i"); 1060 } else { 1061 // Complex comparisons can only be equality comparisons. As such, signed 1062 // and unsigned opcodes are the same. 1063 ResultR = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1064 LHS.first, RHS.first, "cmp.r"); 1065 ResultI = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1066 LHS.second, RHS.second, "cmp.i"); 1067 } 1068 1069 if (E->getOpcode() == BinaryOperator::EQ) { 1070 Result = Builder.CreateAnd(ResultR, ResultI, "and.ri"); 1071 } else { 1072 assert(E->getOpcode() == BinaryOperator::NE && 1073 "Complex comparison other than == or != ?"); 1074 Result = Builder.CreateOr(ResultR, ResultI, "or.ri"); 1075 } 1076 } 1077 1078 return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType()); 1079} 1080 1081Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) { 1082 LValue LHS = EmitLValue(E->getLHS()); 1083 Value *RHS = Visit(E->getRHS()); 1084 1085 // Store the value into the LHS. Bit-fields are handled specially 1086 // because the result is altered by the store, i.e., [C99 6.5.16p1] 1087 // 'An assignment expression has the value of the left operand after 1088 // the assignment...'. 1089 // FIXME: Volatility! 1090 if (LHS.isBitfield()) 1091 CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, E->getType(), 1092 &RHS); 1093 else 1094 CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS, E->getType()); 1095 1096 // Return the RHS. 1097 return RHS; 1098} 1099 1100Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) { 1101 // If we have 0 && RHS, see if we can elide RHS, if so, just return 0. 1102 // If we have 1 && X, just emit X without inserting the control flow. 1103 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) { 1104 if (Cond == 1) { // If we have 1 && X, just emit X. 1105 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1106 // ZExt result to int. 1107 return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "land.ext"); 1108 } 1109 1110 // 0 && RHS: If it is safe, just elide the RHS, and return 0. 1111 if (!CGF.ContainsLabel(E->getRHS())) 1112 return llvm::Constant::getNullValue(CGF.LLVMIntTy); 1113 } 1114 1115 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("land.end"); 1116 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("land.rhs"); 1117 1118 // Branch on the LHS first. If it is false, go to the failure (cont) block. 1119 CGF.EmitBranchOnBoolExpr(E->getLHS(), RHSBlock, ContBlock); 1120 1121 // Any edges into the ContBlock are now from an (indeterminate number of) 1122 // edges from this first condition. All of these values will be false. Start 1123 // setting up the PHI node in the Cont Block for this. 1124 llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::Int1Ty, "", ContBlock); 1125 PN->reserveOperandSpace(2); // Normal case, two inputs. 1126 for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); 1127 PI != PE; ++PI) 1128 PN->addIncoming(llvm::ConstantInt::getFalse(), *PI); 1129 1130 CGF.EmitBlock(RHSBlock); 1131 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1132 1133 // Reaquire the RHS block, as there may be subblocks inserted. 1134 RHSBlock = Builder.GetInsertBlock(); 1135 1136 // Emit an unconditional branch from this block to ContBlock. Insert an entry 1137 // into the phi node for the edge with the value of RHSCond. 1138 CGF.EmitBlock(ContBlock); 1139 PN->addIncoming(RHSCond, RHSBlock); 1140 1141 // ZExt result to int. 1142 return Builder.CreateZExt(PN, CGF.LLVMIntTy, "land.ext"); 1143} 1144 1145Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) { 1146 // If we have 1 || RHS, see if we can elide RHS, if so, just return 1. 1147 // If we have 0 || X, just emit X without inserting the control flow. 1148 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) { 1149 if (Cond == -1) { // If we have 0 || X, just emit X. 1150 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1151 // ZExt result to int. 1152 return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "lor.ext"); 1153 } 1154 1155 // 1 || RHS: If it is safe, just elide the RHS, and return 1. 1156 if (!CGF.ContainsLabel(E->getRHS())) 1157 return llvm::ConstantInt::get(CGF.LLVMIntTy, 1); 1158 } 1159 1160 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("lor.end"); 1161 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("lor.rhs"); 1162 1163 // Branch on the LHS first. If it is true, go to the success (cont) block. 1164 CGF.EmitBranchOnBoolExpr(E->getLHS(), ContBlock, RHSBlock); 1165 1166 // Any edges into the ContBlock are now from an (indeterminate number of) 1167 // edges from this first condition. All of these values will be true. Start 1168 // setting up the PHI node in the Cont Block for this. 1169 llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::Int1Ty, "", ContBlock); 1170 PN->reserveOperandSpace(2); // Normal case, two inputs. 1171 for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); 1172 PI != PE; ++PI) 1173 PN->addIncoming(llvm::ConstantInt::getTrue(), *PI); 1174 1175 // Emit the RHS condition as a bool value. 1176 CGF.EmitBlock(RHSBlock); 1177 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1178 1179 // Reaquire the RHS block, as there may be subblocks inserted. 1180 RHSBlock = Builder.GetInsertBlock(); 1181 1182 // Emit an unconditional branch from this block to ContBlock. Insert an entry 1183 // into the phi node for the edge with the value of RHSCond. 1184 CGF.EmitBlock(ContBlock); 1185 PN->addIncoming(RHSCond, RHSBlock); 1186 1187 // ZExt result to int. 1188 return Builder.CreateZExt(PN, CGF.LLVMIntTy, "lor.ext"); 1189} 1190 1191Value *ScalarExprEmitter::VisitBinComma(const BinaryOperator *E) { 1192 CGF.EmitStmt(E->getLHS()); 1193 CGF.EnsureInsertPoint(); 1194 return Visit(E->getRHS()); 1195} 1196 1197//===----------------------------------------------------------------------===// 1198// Other Operators 1199//===----------------------------------------------------------------------===// 1200 1201/// isCheapEnoughToEvaluateUnconditionally - Return true if the specified 1202/// expression is cheap enough and side-effect-free enough to evaluate 1203/// unconditionally instead of conditionally. This is used to convert control 1204/// flow into selects in some cases. 1205static bool isCheapEnoughToEvaluateUnconditionally(const Expr *E) { 1206 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) 1207 return isCheapEnoughToEvaluateUnconditionally(PE->getSubExpr()); 1208 1209 // TODO: Allow anything we can constant fold to an integer or fp constant. 1210 if (isa<IntegerLiteral>(E) || isa<CharacterLiteral>(E) || 1211 isa<FloatingLiteral>(E)) 1212 return true; 1213 1214 // Non-volatile automatic variables too, to get "cond ? X : Y" where 1215 // X and Y are local variables. 1216 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 1217 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) 1218 if (VD->hasLocalStorage() && !VD->getType().isVolatileQualified()) 1219 return true; 1220 1221 return false; 1222} 1223 1224 1225Value *ScalarExprEmitter:: 1226VisitConditionalOperator(const ConditionalOperator *E) { 1227 // If the condition constant folds and can be elided, try to avoid emitting 1228 // the condition and the dead arm. 1229 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getCond())){ 1230 Expr *Live = E->getLHS(), *Dead = E->getRHS(); 1231 if (Cond == -1) 1232 std::swap(Live, Dead); 1233 1234 // If the dead side doesn't have labels we need, and if the Live side isn't 1235 // the gnu missing ?: extension (which we could handle, but don't bother 1236 // to), just emit the Live part. 1237 if ((!Dead || !CGF.ContainsLabel(Dead)) && // No labels in dead part 1238 Live) // Live part isn't missing. 1239 return Visit(Live); 1240 } 1241 1242 1243 // If this is a really simple expression (like x ? 4 : 5), emit this as a 1244 // select instead of as control flow. We can only do this if it is cheap and 1245 // safe to evaluate the LHS and RHS unconditionally. 1246 if (E->getLHS() && isCheapEnoughToEvaluateUnconditionally(E->getLHS()) && 1247 isCheapEnoughToEvaluateUnconditionally(E->getRHS())) { 1248 llvm::Value *CondV = CGF.EvaluateExprAsBool(E->getCond()); 1249 llvm::Value *LHS = Visit(E->getLHS()); 1250 llvm::Value *RHS = Visit(E->getRHS()); 1251 return Builder.CreateSelect(CondV, LHS, RHS, "cond"); 1252 } 1253 1254 1255 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true"); 1256 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false"); 1257 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end"); 1258 Value *CondVal = 0; 1259 1260 // If we have the GNU missing condition extension, evaluate the conditional 1261 // and then convert it to bool the hard way. We do this explicitly 1262 // because we need the unconverted value for the missing middle value of 1263 // the ?:. 1264 if (E->getLHS() == 0) { 1265 CondVal = CGF.EmitScalarExpr(E->getCond()); 1266 Value *CondBoolVal = 1267 CGF.EmitScalarConversion(CondVal, E->getCond()->getType(), 1268 CGF.getContext().BoolTy); 1269 Builder.CreateCondBr(CondBoolVal, LHSBlock, RHSBlock); 1270 } else { 1271 // Otherwise, just use EmitBranchOnBoolExpr to get small and simple code for 1272 // the branch on bool. 1273 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock); 1274 } 1275 1276 CGF.EmitBlock(LHSBlock); 1277 1278 // Handle the GNU extension for missing LHS. 1279 Value *LHS; 1280 if (E->getLHS()) 1281 LHS = Visit(E->getLHS()); 1282 else // Perform promotions, to handle cases like "short ?: int" 1283 LHS = EmitScalarConversion(CondVal, E->getCond()->getType(), E->getType()); 1284 1285 LHSBlock = Builder.GetInsertBlock(); 1286 CGF.EmitBranch(ContBlock); 1287 1288 CGF.EmitBlock(RHSBlock); 1289 1290 Value *RHS = Visit(E->getRHS()); 1291 RHSBlock = Builder.GetInsertBlock(); 1292 CGF.EmitBranch(ContBlock); 1293 1294 CGF.EmitBlock(ContBlock); 1295 1296 if (!LHS || !RHS) { 1297 assert(E->getType()->isVoidType() && "Non-void value should have a value"); 1298 return 0; 1299 } 1300 1301 // Create a PHI node for the real part. 1302 llvm::PHINode *PN = Builder.CreatePHI(LHS->getType(), "cond"); 1303 PN->reserveOperandSpace(2); 1304 PN->addIncoming(LHS, LHSBlock); 1305 PN->addIncoming(RHS, RHSBlock); 1306 return PN; 1307} 1308 1309Value *ScalarExprEmitter::VisitChooseExpr(ChooseExpr *E) { 1310 // Emit the LHS or RHS as appropriate. 1311 return 1312 Visit(E->isConditionTrue(CGF.getContext()) ? E->getLHS() : E->getRHS()); 1313} 1314 1315Value *ScalarExprEmitter::VisitOverloadExpr(OverloadExpr *E) { 1316 return CGF.EmitCallExpr(E->getFn(), E->arg_begin(), 1317 E->arg_end(CGF.getContext())).getScalarVal(); 1318} 1319 1320Value *ScalarExprEmitter::VisitVAArgExpr(VAArgExpr *VE) { 1321 llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr()); 1322 1323 llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType()); 1324 1325 // If EmitVAArg fails, we fall back to the LLVM instruction. 1326 if (!ArgPtr) 1327 return Builder.CreateVAArg(ArgValue, ConvertType(VE->getType())); 1328 1329 // FIXME: volatile? 1330 return Builder.CreateLoad(ArgPtr); 1331} 1332 1333Value *ScalarExprEmitter::VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { 1334 std::string str; 1335 CGF.getContext().getObjCEncodingForType(E->getEncodedType(), str); 1336 1337 llvm::Constant *C = llvm::ConstantArray::get(str); 1338 C = new llvm::GlobalVariable(C->getType(), true, 1339 llvm::GlobalValue::InternalLinkage, 1340 C, ".str", &CGF.CGM.getModule()); 1341 llvm::Constant *Zero = llvm::Constant::getNullValue(llvm::Type::Int32Ty); 1342 llvm::Constant *Zeros[] = { Zero, Zero }; 1343 C = llvm::ConstantExpr::getGetElementPtr(C, Zeros, 2); 1344 1345 return C; 1346} 1347 1348//===----------------------------------------------------------------------===// 1349// Entry Point into this File 1350//===----------------------------------------------------------------------===// 1351 1352/// EmitComplexExpr - Emit the computation of the specified expression of 1353/// complex type, ignoring the result. 1354Value *CodeGenFunction::EmitScalarExpr(const Expr *E) { 1355 assert(E && !hasAggregateLLVMType(E->getType()) && 1356 "Invalid scalar expression to emit"); 1357 1358 return ScalarExprEmitter(*this).Visit(const_cast<Expr*>(E)); 1359} 1360 1361/// EmitScalarConversion - Emit a conversion from the specified type to the 1362/// specified destination type, both of which are LLVM scalar types. 1363Value *CodeGenFunction::EmitScalarConversion(Value *Src, QualType SrcTy, 1364 QualType DstTy) { 1365 assert(!hasAggregateLLVMType(SrcTy) && !hasAggregateLLVMType(DstTy) && 1366 "Invalid scalar expression to emit"); 1367 return ScalarExprEmitter(*this).EmitScalarConversion(Src, SrcTy, DstTy); 1368} 1369 1370/// EmitComplexToScalarConversion - Emit a conversion from the specified 1371/// complex type to the specified destination type, where the destination 1372/// type is an LLVM scalar type. 1373Value *CodeGenFunction::EmitComplexToScalarConversion(ComplexPairTy Src, 1374 QualType SrcTy, 1375 QualType DstTy) { 1376 assert(SrcTy->isAnyComplexType() && !hasAggregateLLVMType(DstTy) && 1377 "Invalid complex -> scalar conversion"); 1378 return ScalarExprEmitter(*this).EmitComplexToScalarConversion(Src, SrcTy, 1379 DstTy); 1380} 1381 1382Value *CodeGenFunction::EmitShuffleVector(Value* V1, Value *V2, ...) { 1383 assert(V1->getType() == V2->getType() && 1384 "Vector operands must be of the same type"); 1385 unsigned NumElements = 1386 cast<llvm::VectorType>(V1->getType())->getNumElements(); 1387 1388 va_list va; 1389 va_start(va, V2); 1390 1391 llvm::SmallVector<llvm::Constant*, 16> Args; 1392 for (unsigned i = 0; i < NumElements; i++) { 1393 int n = va_arg(va, int); 1394 assert(n >= 0 && n < (int)NumElements * 2 && 1395 "Vector shuffle index out of bounds!"); 1396 Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, n)); 1397 } 1398 1399 const char *Name = va_arg(va, const char *); 1400 va_end(va); 1401 1402 llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements); 1403 1404 return Builder.CreateShuffleVector(V1, V2, Mask, Name); 1405} 1406 1407llvm::Value *CodeGenFunction::EmitVector(llvm::Value * const *Vals, 1408 unsigned NumVals, bool isSplat) { 1409 llvm::Value *Vec 1410 = llvm::UndefValue::get(llvm::VectorType::get(Vals[0]->getType(), NumVals)); 1411 1412 for (unsigned i = 0, e = NumVals; i != e; ++i) { 1413 llvm::Value *Val = isSplat ? Vals[0] : Vals[i]; 1414 llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 1415 Vec = Builder.CreateInsertElement(Vec, Val, Idx, "tmp"); 1416 } 1417 1418 return Vec; 1419} 1420