CGExprScalar.cpp revision bd65cac8de63d108a681035782a71d42954b03ab
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 Value *VisitConditionalOperator(const ConditionalOperator *CO); 324 Value *VisitChooseExpr(ChooseExpr *CE); 325 Value *VisitVAArgExpr(VAArgExpr *VE); 326 Value *VisitObjCStringLiteral(const ObjCStringLiteral *E) { 327 return CGF.EmitObjCStringLiteral(E); 328 } 329 Value *VisitObjCEncodeExpr(const ObjCEncodeExpr *E); 330}; 331} // end anonymous namespace. 332 333//===----------------------------------------------------------------------===// 334// Utilities 335//===----------------------------------------------------------------------===// 336 337/// EmitConversionToBool - Convert the specified expression value to a 338/// boolean (i1) truth value. This is equivalent to "Val != 0". 339Value *ScalarExprEmitter::EmitConversionToBool(Value *Src, QualType SrcType) { 340 assert(SrcType->isCanonical() && "EmitScalarConversion strips typedefs"); 341 342 if (SrcType->isRealFloatingType()) { 343 // Compare against 0.0 for fp scalars. 344 llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType()); 345 return Builder.CreateFCmpUNE(Src, Zero, "tobool"); 346 } 347 348 assert((SrcType->isIntegerType() || isa<llvm::PointerType>(Src->getType())) && 349 "Unknown scalar type to convert"); 350 351 // Because of the type rules of C, we often end up computing a logical value, 352 // then zero extending it to int, then wanting it as a logical value again. 353 // Optimize this common case. 354 if (llvm::ZExtInst *ZI = dyn_cast<llvm::ZExtInst>(Src)) { 355 if (ZI->getOperand(0)->getType() == llvm::Type::Int1Ty) { 356 Value *Result = ZI->getOperand(0); 357 // If there aren't any more uses, zap the instruction to save space. 358 // Note that there can be more uses, for example if this 359 // is the result of an assignment. 360 if (ZI->use_empty()) 361 ZI->eraseFromParent(); 362 return Result; 363 } 364 } 365 366 // Compare against an integer or pointer null. 367 llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType()); 368 return Builder.CreateICmpNE(Src, Zero, "tobool"); 369} 370 371/// EmitScalarConversion - Emit a conversion from the specified type to the 372/// specified destination type, both of which are LLVM scalar types. 373Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType, 374 QualType DstType) { 375 SrcType = CGF.getContext().getCanonicalType(SrcType); 376 DstType = CGF.getContext().getCanonicalType(DstType); 377 if (SrcType == DstType) return Src; 378 379 if (DstType->isVoidType()) return 0; 380 381 // Handle conversions to bool first, they are special: comparisons against 0. 382 if (DstType->isBooleanType()) 383 return EmitConversionToBool(Src, SrcType); 384 385 const llvm::Type *DstTy = ConvertType(DstType); 386 387 // Ignore conversions like int -> uint. 388 if (Src->getType() == DstTy) 389 return Src; 390 391 // Handle pointer conversions next: pointers can only be converted 392 // to/from other pointers and integers. Check for pointer types in 393 // terms of LLVM, as some native types (like Obj-C id) may map to a 394 // pointer type. 395 if (isa<llvm::PointerType>(DstTy)) { 396 // The source value may be an integer, or a pointer. 397 if (isa<llvm::PointerType>(Src->getType())) 398 return Builder.CreateBitCast(Src, DstTy, "conv"); 399 assert(SrcType->isIntegerType() && "Not ptr->ptr or int->ptr conversion?"); 400 return Builder.CreateIntToPtr(Src, DstTy, "conv"); 401 } 402 403 if (isa<llvm::PointerType>(Src->getType())) { 404 // Must be an ptr to int cast. 405 assert(isa<llvm::IntegerType>(DstTy) && "not ptr->int?"); 406 return Builder.CreatePtrToInt(Src, DstTy, "conv"); 407 } 408 409 // A scalar can be splatted to an extended vector of the same element type 410 if (DstType->isExtVectorType() && !isa<VectorType>(SrcType)) { 411 // Cast the scalar to element type 412 QualType EltTy = DstType->getAsExtVectorType()->getElementType(); 413 llvm::Value *Elt = EmitScalarConversion(Src, SrcType, EltTy); 414 415 // Insert the element in element zero of an undef vector 416 llvm::Value *UnV = llvm::UndefValue::get(DstTy); 417 llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, 0); 418 UnV = Builder.CreateInsertElement(UnV, Elt, Idx, "tmp"); 419 420 // Splat the element across to all elements 421 llvm::SmallVector<llvm::Constant*, 16> Args; 422 unsigned NumElements = cast<llvm::VectorType>(DstTy)->getNumElements(); 423 for (unsigned i = 0; i < NumElements; i++) 424 Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0)); 425 426 llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements); 427 llvm::Value *Yay = Builder.CreateShuffleVector(UnV, UnV, Mask, "splat"); 428 return Yay; 429 } 430 431 // Allow bitcast from vector to integer/fp of the same size. 432 if (isa<llvm::VectorType>(Src->getType()) || 433 isa<llvm::VectorType>(DstTy)) 434 return Builder.CreateBitCast(Src, DstTy, "conv"); 435 436 // Finally, we have the arithmetic types: real int/float. 437 if (isa<llvm::IntegerType>(Src->getType())) { 438 bool InputSigned = SrcType->isSignedIntegerType(); 439 if (isa<llvm::IntegerType>(DstTy)) 440 return Builder.CreateIntCast(Src, DstTy, InputSigned, "conv"); 441 else if (InputSigned) 442 return Builder.CreateSIToFP(Src, DstTy, "conv"); 443 else 444 return Builder.CreateUIToFP(Src, DstTy, "conv"); 445 } 446 447 assert(Src->getType()->isFloatingPoint() && "Unknown real conversion"); 448 if (isa<llvm::IntegerType>(DstTy)) { 449 if (DstType->isSignedIntegerType()) 450 return Builder.CreateFPToSI(Src, DstTy, "conv"); 451 else 452 return Builder.CreateFPToUI(Src, DstTy, "conv"); 453 } 454 455 assert(DstTy->isFloatingPoint() && "Unknown real conversion"); 456 if (DstTy->getTypeID() < Src->getType()->getTypeID()) 457 return Builder.CreateFPTrunc(Src, DstTy, "conv"); 458 else 459 return Builder.CreateFPExt(Src, DstTy, "conv"); 460} 461 462/// EmitComplexToScalarConversion - Emit a conversion from the specified 463/// complex type to the specified destination type, where the destination 464/// type is an LLVM scalar type. 465Value *ScalarExprEmitter:: 466EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src, 467 QualType SrcTy, QualType DstTy) { 468 // Get the source element type. 469 SrcTy = SrcTy->getAsComplexType()->getElementType(); 470 471 // Handle conversions to bool first, they are special: comparisons against 0. 472 if (DstTy->isBooleanType()) { 473 // Complex != 0 -> (Real != 0) | (Imag != 0) 474 Src.first = EmitScalarConversion(Src.first, SrcTy, DstTy); 475 Src.second = EmitScalarConversion(Src.second, SrcTy, DstTy); 476 return Builder.CreateOr(Src.first, Src.second, "tobool"); 477 } 478 479 // C99 6.3.1.7p2: "When a value of complex type is converted to a real type, 480 // the imaginary part of the complex value is discarded and the value of the 481 // real part is converted according to the conversion rules for the 482 // corresponding real type. 483 return EmitScalarConversion(Src.first, SrcTy, DstTy); 484} 485 486 487//===----------------------------------------------------------------------===// 488// Visitor Methods 489//===----------------------------------------------------------------------===// 490 491Value *ScalarExprEmitter::VisitExpr(Expr *E) { 492 CGF.ErrorUnsupported(E, "scalar expression"); 493 if (E->getType()->isVoidType()) 494 return 0; 495 return llvm::UndefValue::get(CGF.ConvertType(E->getType())); 496} 497 498Value *ScalarExprEmitter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) { 499 llvm::SmallVector<llvm::Constant*, 32> indices; 500 for (unsigned i = 2; i < E->getNumSubExprs(); i++) { 501 indices.push_back(cast<llvm::Constant>(CGF.EmitScalarExpr(E->getExpr(i)))); 502 } 503 Value* V1 = CGF.EmitScalarExpr(E->getExpr(0)); 504 Value* V2 = CGF.EmitScalarExpr(E->getExpr(1)); 505 Value* SV = llvm::ConstantVector::get(indices.begin(), indices.size()); 506 return Builder.CreateShuffleVector(V1, V2, SV, "shuffle"); 507} 508 509Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) { 510 // Emit subscript expressions in rvalue context's. For most cases, this just 511 // loads the lvalue formed by the subscript expr. However, we have to be 512 // careful, because the base of a vector subscript is occasionally an rvalue, 513 // so we can't get it as an lvalue. 514 if (!E->getBase()->getType()->isVectorType()) 515 return EmitLoadOfLValue(E); 516 517 // Handle the vector case. The base must be a vector, the index must be an 518 // integer value. 519 Value *Base = Visit(E->getBase()); 520 Value *Idx = Visit(E->getIdx()); 521 522 // FIXME: Convert Idx to i32 type. 523 return Builder.CreateExtractElement(Base, Idx, "vecext"); 524} 525 526/// VisitImplicitCastExpr - Implicit casts are the same as normal casts, but 527/// also handle things like function to pointer-to-function decay, and array to 528/// pointer decay. 529Value *ScalarExprEmitter::VisitImplicitCastExpr(const ImplicitCastExpr *E) { 530 const Expr *Op = E->getSubExpr(); 531 532 // If this is due to array->pointer conversion, emit the array expression as 533 // an l-value. 534 if (Op->getType()->isArrayType()) { 535 // FIXME: For now we assume that all source arrays map to LLVM arrays. This 536 // will not true when we add support for VLAs. 537 Value *V = EmitLValue(Op).getAddress(); // Bitfields can't be arrays. 538 539 if (!Op->getType()->isVariableArrayType()) { 540 assert(isa<llvm::PointerType>(V->getType()) && "Expected pointer"); 541 assert(isa<llvm::ArrayType>(cast<llvm::PointerType>(V->getType()) 542 ->getElementType()) && 543 "Expected pointer to array"); 544 V = Builder.CreateStructGEP(V, 0, "arraydecay"); 545 } 546 547 // The resultant pointer type can be implicitly casted to other pointer 548 // types as well (e.g. void*) and can be implicitly converted to integer. 549 const llvm::Type *DestTy = ConvertType(E->getType()); 550 if (V->getType() != DestTy) { 551 if (isa<llvm::PointerType>(DestTy)) 552 V = Builder.CreateBitCast(V, DestTy, "ptrconv"); 553 else { 554 assert(isa<llvm::IntegerType>(DestTy) && "Unknown array decay"); 555 V = Builder.CreatePtrToInt(V, DestTy, "ptrconv"); 556 } 557 } 558 return V; 559 560 } else if (E->getType()->isReferenceType()) { 561 return EmitLValue(Op).getAddress(); 562 } 563 564 return EmitCastExpr(Op, E->getType()); 565} 566 567 568// VisitCastExpr - Emit code for an explicit or implicit cast. Implicit casts 569// have to handle a more broad range of conversions than explicit casts, as they 570// handle things like function to ptr-to-function decay etc. 571Value *ScalarExprEmitter::EmitCastExpr(const Expr *E, QualType DestTy) { 572 // Handle cases where the source is an non-complex type. 573 574 if (!CGF.hasAggregateLLVMType(E->getType())) { 575 Value *Src = Visit(const_cast<Expr*>(E)); 576 577 // Use EmitScalarConversion to perform the conversion. 578 return EmitScalarConversion(Src, E->getType(), DestTy); 579 } 580 581 if (E->getType()->isAnyComplexType()) { 582 // Handle cases where the source is a complex type. 583 return EmitComplexToScalarConversion(CGF.EmitComplexExpr(E), E->getType(), 584 DestTy); 585 } 586 587 // Okay, this is a cast from an aggregate. It must be a cast to void. Just 588 // evaluate the result and return. 589 CGF.EmitAggExpr(E, 0, false); 590 return 0; 591} 592 593Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) { 594 return CGF.EmitCompoundStmt(*E->getSubStmt(), 595 !E->getType()->isVoidType()).getScalarVal(); 596} 597 598 599//===----------------------------------------------------------------------===// 600// Unary Operators 601//===----------------------------------------------------------------------===// 602 603Value *ScalarExprEmitter::VisitPrePostIncDec(const UnaryOperator *E, 604 bool isInc, bool isPre) { 605 LValue LV = EmitLValue(E->getSubExpr()); 606 // FIXME: Handle volatile! 607 Value *InVal = CGF.EmitLoadOfLValue(LV, // false 608 E->getSubExpr()->getType()).getScalarVal(); 609 610 int AmountVal = isInc ? 1 : -1; 611 612 Value *NextVal; 613 if (isa<llvm::PointerType>(InVal->getType())) { 614 // FIXME: This isn't right for VLAs. 615 NextVal = llvm::ConstantInt::get(llvm::Type::Int32Ty, AmountVal); 616 NextVal = Builder.CreateGEP(InVal, NextVal, "ptrincdec"); 617 } else if (InVal->getType() == llvm::Type::Int1Ty && isInc) { 618 // Bool++ is an interesting case, due to promotion rules, we get: 619 // Bool++ -> Bool = Bool+1 -> Bool = (int)Bool+1 -> 620 // Bool = ((int)Bool+1) != 0 621 // An interesting aspect of this is that increment is always true. 622 // Decrement does not have this property. 623 NextVal = llvm::ConstantInt::getTrue(); 624 } else { 625 // Add the inc/dec to the real part. 626 if (isa<llvm::IntegerType>(InVal->getType())) 627 NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal); 628 else if (InVal->getType() == llvm::Type::FloatTy) 629 NextVal = 630 llvm::ConstantFP::get(llvm::APFloat(static_cast<float>(AmountVal))); 631 else if (InVal->getType() == llvm::Type::DoubleTy) 632 NextVal = 633 llvm::ConstantFP::get(llvm::APFloat(static_cast<double>(AmountVal))); 634 else { 635 llvm::APFloat F(static_cast<float>(AmountVal)); 636 bool ignored; 637 F.convert(CGF.Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero, 638 &ignored); 639 NextVal = llvm::ConstantFP::get(F); 640 } 641 NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec"); 642 } 643 644 // Store the updated result through the lvalue. 645 CGF.EmitStoreThroughLValue(RValue::get(NextVal), LV, 646 E->getSubExpr()->getType()); 647 648 // If this is a postinc, return the value read from memory, otherwise use the 649 // updated value. 650 return isPre ? NextVal : InVal; 651} 652 653 654Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) { 655 Value *Op = Visit(E->getSubExpr()); 656 return Builder.CreateNeg(Op, "neg"); 657} 658 659Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) { 660 Value *Op = Visit(E->getSubExpr()); 661 return Builder.CreateNot(Op, "neg"); 662} 663 664Value *ScalarExprEmitter::VisitUnaryLNot(const UnaryOperator *E) { 665 // Compare operand to zero. 666 Value *BoolVal = CGF.EvaluateExprAsBool(E->getSubExpr()); 667 668 // Invert value. 669 // TODO: Could dynamically modify easy computations here. For example, if 670 // the operand is an icmp ne, turn into icmp eq. 671 BoolVal = Builder.CreateNot(BoolVal, "lnot"); 672 673 // ZExt result to int. 674 return Builder.CreateZExt(BoolVal, CGF.LLVMIntTy, "lnot.ext"); 675} 676 677/// VisitSizeOfAlignOfExpr - Return the size or alignment of the type of 678/// argument of the sizeof expression as an integer. 679Value * 680ScalarExprEmitter::VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E) { 681 QualType TypeToSize = E->getTypeOfArgument(); 682 if (E->isSizeOf()) { 683 if (const VariableArrayType *VAT = 684 CGF.getContext().getAsVariableArrayType(TypeToSize)) { 685 if (E->isArgumentType()) { 686 // sizeof(type) - make sure to emit the VLA size. 687 CGF.EmitVLASize(TypeToSize); 688 } 689 690 return CGF.GetVLASize(VAT); 691 } 692 } 693 694 // If this isn't sizeof(vla), the result must be constant; use the 695 // constant folding logic so we don't have to duplicate it here. 696 Expr::EvalResult Result; 697 E->Evaluate(Result, CGF.getContext()); 698 return llvm::ConstantInt::get(Result.Val.getInt()); 699} 700 701Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E) { 702 Expr *Op = E->getSubExpr(); 703 if (Op->getType()->isAnyComplexType()) 704 return CGF.EmitComplexExpr(Op).first; 705 return Visit(Op); 706} 707Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E) { 708 Expr *Op = E->getSubExpr(); 709 if (Op->getType()->isAnyComplexType()) 710 return CGF.EmitComplexExpr(Op).second; 711 712 // __imag on a scalar returns zero. Emit it the subexpr to ensure side 713 // effects are evaluated. 714 CGF.EmitScalarExpr(Op); 715 return llvm::Constant::getNullValue(ConvertType(E->getType())); 716} 717 718Value *ScalarExprEmitter::VisitUnaryOffsetOf(const UnaryOperator *E) 719{ 720 const Expr* SubExpr = E->getSubExpr(); 721 const llvm::Type* ResultType = ConvertType(E->getType()); 722 llvm::Value* Result = llvm::Constant::getNullValue(ResultType); 723 while (!isa<CompoundLiteralExpr>(SubExpr)) { 724 if (const MemberExpr *ME = dyn_cast<MemberExpr>(SubExpr)) { 725 SubExpr = ME->getBase(); 726 QualType Ty = SubExpr->getType(); 727 728 RecordDecl *RD = Ty->getAsRecordType()->getDecl(); 729 const ASTRecordLayout &RL = CGF.getContext().getASTRecordLayout(RD); 730 FieldDecl *FD = cast<FieldDecl>(ME->getMemberDecl()); 731 732 // FIXME: This is linear time. And the fact that we're indexing 733 // into the layout by position in the record means that we're 734 // either stuck numbering the fields in the AST or we have to keep 735 // the linear search (yuck and yuck). 736 unsigned i = 0; 737 for (RecordDecl::field_iterator Field = RD->field_begin(), 738 FieldEnd = RD->field_end(); 739 Field != FieldEnd; (void)++Field, ++i) { 740 if (*Field == FD) 741 break; 742 } 743 744 llvm::Value* Offset = 745 llvm::ConstantInt::get(ResultType, RL.getFieldOffset(i) / 8); 746 Result = Builder.CreateAdd(Result, Offset); 747 } else if (const ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(SubExpr)) { 748 SubExpr = ASE->getBase(); 749 int64_t size = CGF.getContext().getTypeSize(ASE->getType()) / 8; 750 llvm::Value* ElemSize = llvm::ConstantInt::get(ResultType, size); 751 llvm::Value* ElemIndex = CGF.EmitScalarExpr(ASE->getIdx()); 752 bool IndexSigned = ASE->getIdx()->getType()->isSignedIntegerType(); 753 ElemIndex = Builder.CreateIntCast(ElemIndex, ResultType, IndexSigned); 754 llvm::Value* Offset = Builder.CreateMul(ElemSize, ElemIndex); 755 Result = Builder.CreateAdd(Result, Offset); 756 } else { 757 assert(0 && "This should be impossible!"); 758 } 759 } 760 return Result; 761} 762 763//===----------------------------------------------------------------------===// 764// Binary Operators 765//===----------------------------------------------------------------------===// 766 767BinOpInfo ScalarExprEmitter::EmitBinOps(const BinaryOperator *E) { 768 BinOpInfo Result; 769 Result.LHS = Visit(E->getLHS()); 770 Result.RHS = Visit(E->getRHS()); 771 Result.Ty = E->getType(); 772 Result.E = E; 773 return Result; 774} 775 776Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E, 777 Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) { 778 QualType LHSTy = E->getLHS()->getType(), RHSTy = E->getRHS()->getType(); 779 780 BinOpInfo OpInfo; 781 782 // Load the LHS and RHS operands. 783 LValue LHSLV = EmitLValue(E->getLHS()); 784 OpInfo.LHS = EmitLoadOfLValue(LHSLV, LHSTy); 785 786 // Determine the computation type. If the RHS is complex, then this is one of 787 // the add/sub/mul/div operators. All of these operators can be computed in 788 // with just their real component even though the computation domain really is 789 // complex. 790 QualType ComputeType = E->getComputationType(); 791 792 // If the computation type is complex, then the RHS is complex. Emit the RHS. 793 if (const ComplexType *CT = ComputeType->getAsComplexType()) { 794 ComputeType = CT->getElementType(); 795 796 // Emit the RHS, only keeping the real component. 797 OpInfo.RHS = CGF.EmitComplexExpr(E->getRHS()).first; 798 RHSTy = RHSTy->getAsComplexType()->getElementType(); 799 } else { 800 // Otherwise the RHS is a simple scalar value. 801 OpInfo.RHS = Visit(E->getRHS()); 802 } 803 804 QualType LComputeTy, RComputeTy, ResultTy; 805 806 // Compound assignment does not contain enough information about all 807 // the types involved for pointer arithmetic cases. Figure it out 808 // here for now. 809 if (E->getLHS()->getType()->isPointerType()) { 810 // Pointer arithmetic cases: ptr +=,-= int and ptr -= ptr, 811 assert((E->getOpcode() == BinaryOperator::AddAssign || 812 E->getOpcode() == BinaryOperator::SubAssign) && 813 "Invalid compound assignment operator on pointer type."); 814 LComputeTy = E->getLHS()->getType(); 815 816 if (E->getRHS()->getType()->isPointerType()) { 817 // Degenerate case of (ptr -= ptr) allowed by GCC implicit cast 818 // extension, the conversion from the pointer difference back to 819 // the LHS type is handled at the end. 820 assert(E->getOpcode() == BinaryOperator::SubAssign && 821 "Invalid compound assignment operator on pointer type."); 822 RComputeTy = E->getLHS()->getType(); 823 ResultTy = CGF.getContext().getPointerDiffType(); 824 } else { 825 RComputeTy = E->getRHS()->getType(); 826 ResultTy = LComputeTy; 827 } 828 } else if (E->getRHS()->getType()->isPointerType()) { 829 // Degenerate case of (int += ptr) allowed by GCC implicit cast 830 // extension. 831 assert(E->getOpcode() == BinaryOperator::AddAssign && 832 "Invalid compound assignment operator on pointer type."); 833 LComputeTy = E->getLHS()->getType(); 834 RComputeTy = E->getRHS()->getType(); 835 ResultTy = RComputeTy; 836 } else { 837 LComputeTy = RComputeTy = ResultTy = ComputeType; 838 } 839 840 // Convert the LHS/RHS values to the computation type. 841 OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy, LComputeTy); 842 OpInfo.RHS = EmitScalarConversion(OpInfo.RHS, RHSTy, RComputeTy); 843 OpInfo.Ty = ResultTy; 844 OpInfo.E = E; 845 846 // Expand the binary operator. 847 Value *Result = (this->*Func)(OpInfo); 848 849 // Convert the result back to the LHS type. 850 Result = EmitScalarConversion(Result, ResultTy, LHSTy); 851 852 // Store the result value into the LHS lvalue. Bit-fields are 853 // handled specially because the result is altered by the store, 854 // i.e., [C99 6.5.16p1] 'An assignment expression has the value of 855 // the left operand after the assignment...'. 856 if (LHSLV.isBitfield()) 857 CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, LHSTy, 858 &Result); 859 else 860 CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV, LHSTy); 861 862 return Result; 863} 864 865 866Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) { 867 if (Ops.LHS->getType()->isFPOrFPVector()) 868 return Builder.CreateFDiv(Ops.LHS, Ops.RHS, "div"); 869 else if (Ops.Ty->isUnsignedIntegerType()) 870 return Builder.CreateUDiv(Ops.LHS, Ops.RHS, "div"); 871 else 872 return Builder.CreateSDiv(Ops.LHS, Ops.RHS, "div"); 873} 874 875Value *ScalarExprEmitter::EmitRem(const BinOpInfo &Ops) { 876 // Rem in C can't be a floating point type: C99 6.5.5p2. 877 if (Ops.Ty->isUnsignedIntegerType()) 878 return Builder.CreateURem(Ops.LHS, Ops.RHS, "rem"); 879 else 880 return Builder.CreateSRem(Ops.LHS, Ops.RHS, "rem"); 881} 882 883 884Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &Ops) { 885 if (!Ops.Ty->isPointerType()) 886 return Builder.CreateAdd(Ops.LHS, Ops.RHS, "add"); 887 888 // FIXME: What about a pointer to a VLA? 889 Value *Ptr, *Idx; 890 Expr *IdxExp; 891 const PointerType *PT; 892 if ((PT = Ops.E->getLHS()->getType()->getAsPointerType())) { 893 Ptr = Ops.LHS; 894 Idx = Ops.RHS; 895 IdxExp = Ops.E->getRHS(); 896 } else { // int + pointer 897 PT = Ops.E->getRHS()->getType()->getAsPointerType(); 898 assert(PT && "Invalid add expr"); 899 Ptr = Ops.RHS; 900 Idx = Ops.LHS; 901 IdxExp = Ops.E->getLHS(); 902 } 903 904 unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth(); 905 if (Width < CGF.LLVMPointerWidth) { 906 // Zero or sign extend the pointer value based on whether the index is 907 // signed or not. 908 const llvm::Type *IdxType = llvm::IntegerType::get(CGF.LLVMPointerWidth); 909 if (IdxExp->getType()->isSignedIntegerType()) 910 Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext"); 911 else 912 Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext"); 913 } 914 915 // Explicitly handle GNU void* and function pointer arithmetic 916 // extensions. The GNU void* casts amount to no-ops since our void* 917 // type is i8*, but this is future proof. 918 const QualType ElementType = PT->getPointeeType(); 919 if (ElementType->isVoidType() || ElementType->isFunctionType()) { 920 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 921 Value *Casted = Builder.CreateBitCast(Ptr, i8Ty); 922 Value *Res = Builder.CreateGEP(Casted, Idx, "sub.ptr"); 923 return Builder.CreateBitCast(Res, Ptr->getType()); 924 } 925 926 return Builder.CreateGEP(Ptr, Idx, "add.ptr"); 927} 928 929Value *ScalarExprEmitter::EmitSub(const BinOpInfo &Ops) { 930 if (!isa<llvm::PointerType>(Ops.LHS->getType())) 931 return Builder.CreateSub(Ops.LHS, Ops.RHS, "sub"); 932 933 const QualType LHSType = Ops.E->getLHS()->getType(); 934 const QualType LHSElementType = LHSType->getAsPointerType()->getPointeeType(); 935 if (!isa<llvm::PointerType>(Ops.RHS->getType())) { 936 // pointer - int 937 Value *Idx = Ops.RHS; 938 unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth(); 939 if (Width < CGF.LLVMPointerWidth) { 940 // Zero or sign extend the pointer value based on whether the index is 941 // signed or not. 942 const llvm::Type *IdxType = llvm::IntegerType::get(CGF.LLVMPointerWidth); 943 if (Ops.E->getRHS()->getType()->isSignedIntegerType()) 944 Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext"); 945 else 946 Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext"); 947 } 948 Idx = Builder.CreateNeg(Idx, "sub.ptr.neg"); 949 950 // FIXME: The pointer could point to a VLA. 951 952 // Explicitly handle GNU void* and function pointer arithmetic 953 // extensions. The GNU void* casts amount to no-ops since our 954 // void* type is i8*, but this is future proof. 955 if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) { 956 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 957 Value *LHSCasted = Builder.CreateBitCast(Ops.LHS, i8Ty); 958 Value *Res = Builder.CreateGEP(LHSCasted, Idx, "sub.ptr"); 959 return Builder.CreateBitCast(Res, Ops.LHS->getType()); 960 } 961 962 return Builder.CreateGEP(Ops.LHS, Idx, "sub.ptr"); 963 } else { 964 // pointer - pointer 965 Value *LHS = Ops.LHS; 966 Value *RHS = Ops.RHS; 967 968 uint64_t ElementSize; 969 970 // Handle GCC extension for pointer arithmetic on void* and function pointer 971 // types. 972 if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) { 973 ElementSize = 1; 974 } else { 975 ElementSize = CGF.getContext().getTypeSize(LHSElementType) / 8; 976 } 977 978 const llvm::Type *ResultType = ConvertType(Ops.Ty); 979 LHS = Builder.CreatePtrToInt(LHS, ResultType, "sub.ptr.lhs.cast"); 980 RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast"); 981 Value *BytesBetween = Builder.CreateSub(LHS, RHS, "sub.ptr.sub"); 982 983 // Optimize out the shift for element size of 1. 984 if (ElementSize == 1) 985 return BytesBetween; 986 987 // HACK: LLVM doesn't have an divide instruction that 'knows' there is no 988 // remainder. As such, we handle common power-of-two cases here to generate 989 // better code. See PR2247. 990 if (llvm::isPowerOf2_64(ElementSize)) { 991 Value *ShAmt = 992 llvm::ConstantInt::get(ResultType, llvm::Log2_64(ElementSize)); 993 return Builder.CreateAShr(BytesBetween, ShAmt, "sub.ptr.shr"); 994 } 995 996 // Otherwise, do a full sdiv. 997 Value *BytesPerElt = llvm::ConstantInt::get(ResultType, ElementSize); 998 return Builder.CreateSDiv(BytesBetween, BytesPerElt, "sub.ptr.div"); 999 } 1000} 1001 1002Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) { 1003 // LLVM requires the LHS and RHS to be the same type: promote or truncate the 1004 // RHS to the same size as the LHS. 1005 Value *RHS = Ops.RHS; 1006 if (Ops.LHS->getType() != RHS->getType()) 1007 RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); 1008 1009 return Builder.CreateShl(Ops.LHS, RHS, "shl"); 1010} 1011 1012Value *ScalarExprEmitter::EmitShr(const BinOpInfo &Ops) { 1013 // LLVM requires the LHS and RHS to be the same type: promote or truncate the 1014 // RHS to the same size as the LHS. 1015 Value *RHS = Ops.RHS; 1016 if (Ops.LHS->getType() != RHS->getType()) 1017 RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); 1018 1019 if (Ops.Ty->isUnsignedIntegerType()) 1020 return Builder.CreateLShr(Ops.LHS, RHS, "shr"); 1021 return Builder.CreateAShr(Ops.LHS, RHS, "shr"); 1022} 1023 1024Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,unsigned UICmpOpc, 1025 unsigned SICmpOpc, unsigned FCmpOpc) { 1026 Value *Result; 1027 QualType LHSTy = E->getLHS()->getType(); 1028 if (!LHSTy->isAnyComplexType() && !LHSTy->isVectorType()) { 1029 Value *LHS = Visit(E->getLHS()); 1030 Value *RHS = Visit(E->getRHS()); 1031 1032 if (LHS->getType()->isFloatingPoint()) { 1033 Result = Builder.CreateFCmp((llvm::CmpInst::Predicate)FCmpOpc, 1034 LHS, RHS, "cmp"); 1035 } else if (LHSTy->isSignedIntegerType()) { 1036 Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)SICmpOpc, 1037 LHS, RHS, "cmp"); 1038 } else { 1039 // Unsigned integers and pointers. 1040 Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1041 LHS, RHS, "cmp"); 1042 } 1043 } else if (LHSTy->isVectorType()) { 1044 Value *LHS = Visit(E->getLHS()); 1045 Value *RHS = Visit(E->getRHS()); 1046 1047 if (LHS->getType()->isFPOrFPVector()) { 1048 Result = Builder.CreateVFCmp((llvm::CmpInst::Predicate)FCmpOpc, 1049 LHS, RHS, "cmp"); 1050 } else if (LHSTy->isUnsignedIntegerType()) { 1051 Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)UICmpOpc, 1052 LHS, RHS, "cmp"); 1053 } else { 1054 // Signed integers and pointers. 1055 Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)SICmpOpc, 1056 LHS, RHS, "cmp"); 1057 } 1058 return Result; 1059 } else { 1060 // Complex Comparison: can only be an equality comparison. 1061 CodeGenFunction::ComplexPairTy LHS = CGF.EmitComplexExpr(E->getLHS()); 1062 CodeGenFunction::ComplexPairTy RHS = CGF.EmitComplexExpr(E->getRHS()); 1063 1064 QualType CETy = LHSTy->getAsComplexType()->getElementType(); 1065 1066 Value *ResultR, *ResultI; 1067 if (CETy->isRealFloatingType()) { 1068 ResultR = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc, 1069 LHS.first, RHS.first, "cmp.r"); 1070 ResultI = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc, 1071 LHS.second, RHS.second, "cmp.i"); 1072 } else { 1073 // Complex comparisons can only be equality comparisons. As such, signed 1074 // and unsigned opcodes are the same. 1075 ResultR = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1076 LHS.first, RHS.first, "cmp.r"); 1077 ResultI = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1078 LHS.second, RHS.second, "cmp.i"); 1079 } 1080 1081 if (E->getOpcode() == BinaryOperator::EQ) { 1082 Result = Builder.CreateAnd(ResultR, ResultI, "and.ri"); 1083 } else { 1084 assert(E->getOpcode() == BinaryOperator::NE && 1085 "Complex comparison other than == or != ?"); 1086 Result = Builder.CreateOr(ResultR, ResultI, "or.ri"); 1087 } 1088 } 1089 1090 return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType()); 1091} 1092 1093Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) { 1094 LValue LHS = EmitLValue(E->getLHS()); 1095 Value *RHS = Visit(E->getRHS()); 1096 1097 // Store the value into the LHS. Bit-fields are handled specially 1098 // because the result is altered by the store, i.e., [C99 6.5.16p1] 1099 // 'An assignment expression has the value of the left operand after 1100 // the assignment...'. 1101 // FIXME: Volatility! 1102 if (LHS.isBitfield()) 1103 CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, E->getType(), 1104 &RHS); 1105 else 1106 CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS, E->getType()); 1107 1108 // Return the RHS. 1109 return RHS; 1110} 1111 1112Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) { 1113 // If we have 0 && RHS, see if we can elide RHS, if so, just return 0. 1114 // If we have 1 && X, just emit X without inserting the control flow. 1115 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) { 1116 if (Cond == 1) { // If we have 1 && X, just emit X. 1117 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1118 // ZExt result to int. 1119 return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "land.ext"); 1120 } 1121 1122 // 0 && RHS: If it is safe, just elide the RHS, and return 0. 1123 if (!CGF.ContainsLabel(E->getRHS())) 1124 return llvm::Constant::getNullValue(CGF.LLVMIntTy); 1125 } 1126 1127 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("land.end"); 1128 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("land.rhs"); 1129 1130 // Branch on the LHS first. If it is false, go to the failure (cont) block. 1131 CGF.EmitBranchOnBoolExpr(E->getLHS(), RHSBlock, ContBlock); 1132 1133 // Any edges into the ContBlock are now from an (indeterminate number of) 1134 // edges from this first condition. All of these values will be false. Start 1135 // setting up the PHI node in the Cont Block for this. 1136 llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::Int1Ty, "", ContBlock); 1137 PN->reserveOperandSpace(2); // Normal case, two inputs. 1138 for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); 1139 PI != PE; ++PI) 1140 PN->addIncoming(llvm::ConstantInt::getFalse(), *PI); 1141 1142 CGF.EmitBlock(RHSBlock); 1143 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1144 1145 // Reaquire the RHS block, as there may be subblocks inserted. 1146 RHSBlock = Builder.GetInsertBlock(); 1147 1148 // Emit an unconditional branch from this block to ContBlock. Insert an entry 1149 // into the phi node for the edge with the value of RHSCond. 1150 CGF.EmitBlock(ContBlock); 1151 PN->addIncoming(RHSCond, RHSBlock); 1152 1153 // ZExt result to int. 1154 return Builder.CreateZExt(PN, CGF.LLVMIntTy, "land.ext"); 1155} 1156 1157Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) { 1158 // If we have 1 || RHS, see if we can elide RHS, if so, just return 1. 1159 // If we have 0 || X, just emit X without inserting the control flow. 1160 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) { 1161 if (Cond == -1) { // If we have 0 || X, just emit X. 1162 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1163 // ZExt result to int. 1164 return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "lor.ext"); 1165 } 1166 1167 // 1 || RHS: If it is safe, just elide the RHS, and return 1. 1168 if (!CGF.ContainsLabel(E->getRHS())) 1169 return llvm::ConstantInt::get(CGF.LLVMIntTy, 1); 1170 } 1171 1172 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("lor.end"); 1173 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("lor.rhs"); 1174 1175 // Branch on the LHS first. If it is true, go to the success (cont) block. 1176 CGF.EmitBranchOnBoolExpr(E->getLHS(), ContBlock, RHSBlock); 1177 1178 // Any edges into the ContBlock are now from an (indeterminate number of) 1179 // edges from this first condition. All of these values will be true. Start 1180 // setting up the PHI node in the Cont Block for this. 1181 llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::Int1Ty, "", ContBlock); 1182 PN->reserveOperandSpace(2); // Normal case, two inputs. 1183 for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); 1184 PI != PE; ++PI) 1185 PN->addIncoming(llvm::ConstantInt::getTrue(), *PI); 1186 1187 // Emit the RHS condition as a bool value. 1188 CGF.EmitBlock(RHSBlock); 1189 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1190 1191 // Reaquire the RHS block, as there may be subblocks inserted. 1192 RHSBlock = Builder.GetInsertBlock(); 1193 1194 // Emit an unconditional branch from this block to ContBlock. Insert an entry 1195 // into the phi node for the edge with the value of RHSCond. 1196 CGF.EmitBlock(ContBlock); 1197 PN->addIncoming(RHSCond, RHSBlock); 1198 1199 // ZExt result to int. 1200 return Builder.CreateZExt(PN, CGF.LLVMIntTy, "lor.ext"); 1201} 1202 1203Value *ScalarExprEmitter::VisitBinComma(const BinaryOperator *E) { 1204 CGF.EmitStmt(E->getLHS()); 1205 CGF.EnsureInsertPoint(); 1206 return Visit(E->getRHS()); 1207} 1208 1209//===----------------------------------------------------------------------===// 1210// Other Operators 1211//===----------------------------------------------------------------------===// 1212 1213/// isCheapEnoughToEvaluateUnconditionally - Return true if the specified 1214/// expression is cheap enough and side-effect-free enough to evaluate 1215/// unconditionally instead of conditionally. This is used to convert control 1216/// flow into selects in some cases. 1217static bool isCheapEnoughToEvaluateUnconditionally(const Expr *E) { 1218 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) 1219 return isCheapEnoughToEvaluateUnconditionally(PE->getSubExpr()); 1220 1221 // TODO: Allow anything we can constant fold to an integer or fp constant. 1222 if (isa<IntegerLiteral>(E) || isa<CharacterLiteral>(E) || 1223 isa<FloatingLiteral>(E)) 1224 return true; 1225 1226 // Non-volatile automatic variables too, to get "cond ? X : Y" where 1227 // X and Y are local variables. 1228 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 1229 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) 1230 if (VD->hasLocalStorage() && !VD->getType().isVolatileQualified()) 1231 return true; 1232 1233 return false; 1234} 1235 1236 1237Value *ScalarExprEmitter:: 1238VisitConditionalOperator(const ConditionalOperator *E) { 1239 // If the condition constant folds and can be elided, try to avoid emitting 1240 // the condition and the dead arm. 1241 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getCond())){ 1242 Expr *Live = E->getLHS(), *Dead = E->getRHS(); 1243 if (Cond == -1) 1244 std::swap(Live, Dead); 1245 1246 // If the dead side doesn't have labels we need, and if the Live side isn't 1247 // the gnu missing ?: extension (which we could handle, but don't bother 1248 // to), just emit the Live part. 1249 if ((!Dead || !CGF.ContainsLabel(Dead)) && // No labels in dead part 1250 Live) // Live part isn't missing. 1251 return Visit(Live); 1252 } 1253 1254 1255 // If this is a really simple expression (like x ? 4 : 5), emit this as a 1256 // select instead of as control flow. We can only do this if it is cheap and 1257 // safe to evaluate the LHS and RHS unconditionally. 1258 if (E->getLHS() && isCheapEnoughToEvaluateUnconditionally(E->getLHS()) && 1259 isCheapEnoughToEvaluateUnconditionally(E->getRHS())) { 1260 llvm::Value *CondV = CGF.EvaluateExprAsBool(E->getCond()); 1261 llvm::Value *LHS = Visit(E->getLHS()); 1262 llvm::Value *RHS = Visit(E->getRHS()); 1263 return Builder.CreateSelect(CondV, LHS, RHS, "cond"); 1264 } 1265 1266 1267 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true"); 1268 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false"); 1269 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end"); 1270 Value *CondVal = 0; 1271 1272 // If we don't have the GNU missing condition extension, emit a branch on 1273 // bool the normal way. 1274 if (E->getLHS()) { 1275 // Otherwise, just use EmitBranchOnBoolExpr to get small and simple code for 1276 // the branch on bool. 1277 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock); 1278 } else { 1279 // Otherwise, for the ?: extension, evaluate the conditional and then 1280 // convert it to bool the hard way. We do this explicitly because we need 1281 // the unconverted value for the missing middle value of the ?:. 1282 CondVal = CGF.EmitScalarExpr(E->getCond()); 1283 1284 // In some cases, EmitScalarConversion will delete the "CondVal" expression 1285 // if there are no extra uses (an optimization). Inhibit this by making an 1286 // extra dead use, because we're going to add a use of CondVal later. We 1287 // don't use the builder for this, because we don't want it to get optimized 1288 // away. This leaves dead code, but the ?: extension isn't common. 1289 new llvm::BitCastInst(CondVal, CondVal->getType(), "dummy?:holder", 1290 Builder.GetInsertBlock()); 1291 1292 Value *CondBoolVal = 1293 CGF.EmitScalarConversion(CondVal, E->getCond()->getType(), 1294 CGF.getContext().BoolTy); 1295 Builder.CreateCondBr(CondBoolVal, LHSBlock, RHSBlock); 1296 } 1297 1298 CGF.EmitBlock(LHSBlock); 1299 1300 // Handle the GNU extension for missing LHS. 1301 Value *LHS; 1302 if (E->getLHS()) 1303 LHS = Visit(E->getLHS()); 1304 else // Perform promotions, to handle cases like "short ?: int" 1305 LHS = EmitScalarConversion(CondVal, E->getCond()->getType(), E->getType()); 1306 1307 LHSBlock = Builder.GetInsertBlock(); 1308 CGF.EmitBranch(ContBlock); 1309 1310 CGF.EmitBlock(RHSBlock); 1311 1312 Value *RHS = Visit(E->getRHS()); 1313 RHSBlock = Builder.GetInsertBlock(); 1314 CGF.EmitBranch(ContBlock); 1315 1316 CGF.EmitBlock(ContBlock); 1317 1318 if (!LHS || !RHS) { 1319 assert(E->getType()->isVoidType() && "Non-void value should have a value"); 1320 return 0; 1321 } 1322 1323 // Create a PHI node for the real part. 1324 llvm::PHINode *PN = Builder.CreatePHI(LHS->getType(), "cond"); 1325 PN->reserveOperandSpace(2); 1326 PN->addIncoming(LHS, LHSBlock); 1327 PN->addIncoming(RHS, RHSBlock); 1328 return PN; 1329} 1330 1331Value *ScalarExprEmitter::VisitChooseExpr(ChooseExpr *E) { 1332 // Emit the LHS or RHS as appropriate. 1333 return 1334 Visit(E->isConditionTrue(CGF.getContext()) ? E->getLHS() : E->getRHS()); 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 1365Value *ScalarExprEmitter::VisitBlockExpr(const BlockExpr *BE) { 1366 llvm::Constant *C = CGF.BuildBlockLiteralTmp(BE); 1367 return C; 1368} 1369 1370//===----------------------------------------------------------------------===// 1371// Entry Point into this File 1372//===----------------------------------------------------------------------===// 1373 1374/// EmitComplexExpr - Emit the computation of the specified expression of 1375/// complex type, ignoring the result. 1376Value *CodeGenFunction::EmitScalarExpr(const Expr *E) { 1377 assert(E && !hasAggregateLLVMType(E->getType()) && 1378 "Invalid scalar expression to emit"); 1379 1380 return ScalarExprEmitter(*this).Visit(const_cast<Expr*>(E)); 1381} 1382 1383/// EmitScalarConversion - Emit a conversion from the specified type to the 1384/// specified destination type, both of which are LLVM scalar types. 1385Value *CodeGenFunction::EmitScalarConversion(Value *Src, QualType SrcTy, 1386 QualType DstTy) { 1387 assert(!hasAggregateLLVMType(SrcTy) && !hasAggregateLLVMType(DstTy) && 1388 "Invalid scalar expression to emit"); 1389 return ScalarExprEmitter(*this).EmitScalarConversion(Src, SrcTy, DstTy); 1390} 1391 1392/// EmitComplexToScalarConversion - Emit a conversion from the specified 1393/// complex type to the specified destination type, where the destination 1394/// type is an LLVM scalar type. 1395Value *CodeGenFunction::EmitComplexToScalarConversion(ComplexPairTy Src, 1396 QualType SrcTy, 1397 QualType DstTy) { 1398 assert(SrcTy->isAnyComplexType() && !hasAggregateLLVMType(DstTy) && 1399 "Invalid complex -> scalar conversion"); 1400 return ScalarExprEmitter(*this).EmitComplexToScalarConversion(Src, SrcTy, 1401 DstTy); 1402} 1403 1404Value *CodeGenFunction::EmitShuffleVector(Value* V1, Value *V2, ...) { 1405 assert(V1->getType() == V2->getType() && 1406 "Vector operands must be of the same type"); 1407 unsigned NumElements = 1408 cast<llvm::VectorType>(V1->getType())->getNumElements(); 1409 1410 va_list va; 1411 va_start(va, V2); 1412 1413 llvm::SmallVector<llvm::Constant*, 16> Args; 1414 for (unsigned i = 0; i < NumElements; i++) { 1415 int n = va_arg(va, int); 1416 assert(n >= 0 && n < (int)NumElements * 2 && 1417 "Vector shuffle index out of bounds!"); 1418 Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, n)); 1419 } 1420 1421 const char *Name = va_arg(va, const char *); 1422 va_end(va); 1423 1424 llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements); 1425 1426 return Builder.CreateShuffleVector(V1, V2, Mask, Name); 1427} 1428 1429llvm::Value *CodeGenFunction::EmitVector(llvm::Value * const *Vals, 1430 unsigned NumVals, bool isSplat) { 1431 llvm::Value *Vec 1432 = llvm::UndefValue::get(llvm::VectorType::get(Vals[0]->getType(), NumVals)); 1433 1434 for (unsigned i = 0, e = NumVals; i != e; ++i) { 1435 llvm::Value *Val = isSplat ? Vals[0] : Vals[i]; 1436 llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 1437 Vec = Builder.CreateInsertElement(Vec, Val, Idx, "tmp"); 1438 } 1439 1440 return Vec; 1441} 1442