CGExprScalar.cpp revision 8f426fa9fca022201fc0944d6c1cb2cf9918db7d
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/Module.h" 26#include "llvm/Support/Compiler.h" 27#include "llvm/Support/CFG.h" 28#include "llvm/Target/TargetData.h" 29#include <cstdarg> 30 31using namespace clang; 32using namespace CodeGen; 33using llvm::Value; 34 35//===----------------------------------------------------------------------===// 36// Scalar Expression Emitter 37//===----------------------------------------------------------------------===// 38 39struct BinOpInfo { 40 Value *LHS; 41 Value *RHS; 42 QualType Ty; // Computation Type. 43 const BinaryOperator *E; 44}; 45 46namespace { 47class VISIBILITY_HIDDEN ScalarExprEmitter 48 : public StmtVisitor<ScalarExprEmitter, Value*> { 49 CodeGenFunction &CGF; 50 CGBuilderTy &Builder; 51 52public: 53 54 ScalarExprEmitter(CodeGenFunction &cgf) : CGF(cgf), 55 Builder(CGF.Builder) { 56 } 57 58 //===--------------------------------------------------------------------===// 59 // Utilities 60 //===--------------------------------------------------------------------===// 61 62 const llvm::Type *ConvertType(QualType T) { return CGF.ConvertType(T); } 63 LValue EmitLValue(const Expr *E) { return CGF.EmitLValue(E); } 64 65 Value *EmitLoadOfLValue(LValue LV, QualType T) { 66 return CGF.EmitLoadOfLValue(LV, T).getScalarVal(); 67 } 68 69 /// EmitLoadOfLValue - Given an expression with complex type that represents a 70 /// value l-value, this method emits the address of the l-value, then loads 71 /// and returns the result. 72 Value *EmitLoadOfLValue(const Expr *E) { 73 return EmitLoadOfLValue(EmitLValue(E), E->getType()); 74 } 75 76 /// EmitConversionToBool - Convert the specified expression value to a 77 /// boolean (i1) truth value. This is equivalent to "Val != 0". 78 Value *EmitConversionToBool(Value *Src, QualType DstTy); 79 80 /// EmitScalarConversion - Emit a conversion from the specified type to the 81 /// specified destination type, both of which are LLVM scalar types. 82 Value *EmitScalarConversion(Value *Src, QualType SrcTy, QualType DstTy); 83 84 /// EmitComplexToScalarConversion - Emit a conversion from the specified 85 /// complex type to the specified destination type, where the destination 86 /// type is an LLVM scalar type. 87 Value *EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src, 88 QualType SrcTy, QualType DstTy); 89 90 //===--------------------------------------------------------------------===// 91 // Visitor Methods 92 //===--------------------------------------------------------------------===// 93 94 Value *VisitStmt(Stmt *S) { 95 S->dump(CGF.getContext().getSourceManager()); 96 assert(0 && "Stmt can't have complex result type!"); 97 return 0; 98 } 99 Value *VisitExpr(Expr *S); 100 Value *VisitParenExpr(ParenExpr *PE) { return Visit(PE->getSubExpr()); } 101 102 // Leaves. 103 Value *VisitIntegerLiteral(const IntegerLiteral *E) { 104 return llvm::ConstantInt::get(E->getValue()); 105 } 106 Value *VisitFloatingLiteral(const FloatingLiteral *E) { 107 return llvm::ConstantFP::get(E->getValue()); 108 } 109 Value *VisitCharacterLiteral(const CharacterLiteral *E) { 110 return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue()); 111 } 112 Value *VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) { 113 return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue()); 114 } 115 Value *VisitCXXZeroInitValueExpr(const CXXZeroInitValueExpr *E) { 116 return llvm::Constant::getNullValue(ConvertType(E->getType())); 117 } 118 Value *VisitGNUNullExpr(const GNUNullExpr *E) { 119 return llvm::Constant::getNullValue(ConvertType(E->getType())); 120 } 121 Value *VisitTypesCompatibleExpr(const TypesCompatibleExpr *E) { 122 return llvm::ConstantInt::get(ConvertType(E->getType()), 123 CGF.getContext().typesAreCompatible( 124 E->getArgType1(), E->getArgType2())); 125 } 126 Value *VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E); 127 Value *VisitAddrLabelExpr(const AddrLabelExpr *E) { 128 llvm::Value *V = 129 llvm::ConstantInt::get(llvm::Type::Int32Ty, 130 CGF.GetIDForAddrOfLabel(E->getLabel())); 131 132 return Builder.CreateIntToPtr(V, ConvertType(E->getType())); 133 } 134 135 // l-values. 136 Value *VisitDeclRefExpr(DeclRefExpr *E) { 137 if (const EnumConstantDecl *EC = dyn_cast<EnumConstantDecl>(E->getDecl())) 138 return llvm::ConstantInt::get(EC->getInitVal()); 139 return EmitLoadOfLValue(E); 140 } 141 Value *VisitObjCSelectorExpr(ObjCSelectorExpr *E) { 142 return CGF.EmitObjCSelectorExpr(E); 143 } 144 Value *VisitObjCProtocolExpr(ObjCProtocolExpr *E) { 145 return CGF.EmitObjCProtocolExpr(E); 146 } 147 Value *VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) { 148 return EmitLoadOfLValue(E); 149 } 150 Value *VisitObjCPropertyRefExpr(ObjCPropertyRefExpr *E) { 151 return EmitLoadOfLValue(E); 152 } 153 Value *VisitObjCKVCRefExpr(ObjCKVCRefExpr *E) { 154 return EmitLoadOfLValue(E); 155 } 156 Value *VisitObjCMessageExpr(ObjCMessageExpr *E) { 157 return CGF.EmitObjCMessageExpr(E).getScalarVal(); 158 } 159 160 Value *VisitArraySubscriptExpr(ArraySubscriptExpr *E); 161 Value *VisitShuffleVectorExpr(ShuffleVectorExpr *E); 162 Value *VisitMemberExpr(Expr *E) { return EmitLoadOfLValue(E); } 163 Value *VisitExtVectorElementExpr(Expr *E) { return EmitLoadOfLValue(E); } 164 Value *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { 165 return EmitLoadOfLValue(E); 166 } 167 Value *VisitStringLiteral(Expr *E) { return EmitLValue(E).getAddress(); } 168 Value *VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { 169 return EmitLValue(E).getAddress(); 170 } 171 172 Value *VisitPredefinedExpr(Expr *E) { return EmitLValue(E).getAddress(); } 173 174 Value *VisitInitListExpr(InitListExpr *E) { 175 unsigned NumInitElements = E->getNumInits(); 176 177 if (E->hadArrayRangeDesignator()) { 178 CGF.ErrorUnsupported(E, "GNU array range designator extension"); 179 } 180 181 const llvm::VectorType *VType = 182 dyn_cast<llvm::VectorType>(ConvertType(E->getType())); 183 184 // We have a scalar in braces. Just use the first element. 185 if (!VType) 186 return Visit(E->getInit(0)); 187 188 unsigned NumVectorElements = VType->getNumElements(); 189 const llvm::Type *ElementType = VType->getElementType(); 190 191 // Emit individual vector element stores. 192 llvm::Value *V = llvm::UndefValue::get(VType); 193 194 // Emit initializers 195 unsigned i; 196 for (i = 0; i < NumInitElements; ++i) { 197 Value *NewV = Visit(E->getInit(i)); 198 Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 199 V = Builder.CreateInsertElement(V, NewV, Idx); 200 } 201 202 // Emit remaining default initializers 203 for (/* Do not initialize i*/; i < NumVectorElements; ++i) { 204 Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 205 llvm::Value *NewV = llvm::Constant::getNullValue(ElementType); 206 V = Builder.CreateInsertElement(V, NewV, Idx); 207 } 208 209 return V; 210 } 211 212 Value *VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) { 213 return llvm::Constant::getNullValue(ConvertType(E->getType())); 214 } 215 Value *VisitImplicitCastExpr(const ImplicitCastExpr *E); 216 Value *VisitCastExpr(const CastExpr *E) { 217 return EmitCastExpr(E->getSubExpr(), E->getType()); 218 } 219 Value *EmitCastExpr(const Expr *E, QualType T); 220 221 Value *VisitCallExpr(const CallExpr *E) { 222 return CGF.EmitCallExpr(E).getScalarVal(); 223 } 224 225 Value *VisitStmtExpr(const StmtExpr *E); 226 227 Value *VisitBlockDeclRefExpr(const BlockDeclRefExpr *E); 228 229 // Unary Operators. 230 Value *VisitPrePostIncDec(const UnaryOperator *E, bool isInc, bool isPre); 231 Value *VisitUnaryPostDec(const UnaryOperator *E) { 232 return VisitPrePostIncDec(E, false, false); 233 } 234 Value *VisitUnaryPostInc(const UnaryOperator *E) { 235 return VisitPrePostIncDec(E, true, false); 236 } 237 Value *VisitUnaryPreDec(const UnaryOperator *E) { 238 return VisitPrePostIncDec(E, false, true); 239 } 240 Value *VisitUnaryPreInc(const UnaryOperator *E) { 241 return VisitPrePostIncDec(E, true, true); 242 } 243 Value *VisitUnaryAddrOf(const UnaryOperator *E) { 244 return EmitLValue(E->getSubExpr()).getAddress(); 245 } 246 Value *VisitUnaryDeref(const Expr *E) { return EmitLoadOfLValue(E); } 247 Value *VisitUnaryPlus(const UnaryOperator *E) { 248 return Visit(E->getSubExpr()); 249 } 250 Value *VisitUnaryMinus (const UnaryOperator *E); 251 Value *VisitUnaryNot (const UnaryOperator *E); 252 Value *VisitUnaryLNot (const UnaryOperator *E); 253 Value *VisitUnaryReal (const UnaryOperator *E); 254 Value *VisitUnaryImag (const UnaryOperator *E); 255 Value *VisitUnaryExtension(const UnaryOperator *E) { 256 return Visit(E->getSubExpr()); 257 } 258 Value *VisitUnaryOffsetOf(const UnaryOperator *E); 259 260 // C++ 261 Value *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) { 262 return Visit(DAE->getExpr()); 263 } 264 Value *VisitCXXThisExpr(CXXThisExpr *TE) { 265 return CGF.LoadCXXThis(); 266 } 267 268 // Binary Operators. 269 Value *EmitMul(const BinOpInfo &Ops) { 270 if (CGF.getContext().getLangOptions().OverflowChecking 271 && Ops.Ty->isSignedIntegerType()) 272 return EmitOverflowCheckedBinOp(Ops); 273 return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul"); 274 } 275 /// Create a binary op that checks for overflow. 276 /// Currently only supports +, - and *. 277 Value *EmitOverflowCheckedBinOp(const BinOpInfo &Ops); 278 Value *EmitDiv(const BinOpInfo &Ops); 279 Value *EmitRem(const BinOpInfo &Ops); 280 Value *EmitAdd(const BinOpInfo &Ops); 281 Value *EmitSub(const BinOpInfo &Ops); 282 Value *EmitShl(const BinOpInfo &Ops); 283 Value *EmitShr(const BinOpInfo &Ops); 284 Value *EmitAnd(const BinOpInfo &Ops) { 285 return Builder.CreateAnd(Ops.LHS, Ops.RHS, "and"); 286 } 287 Value *EmitXor(const BinOpInfo &Ops) { 288 return Builder.CreateXor(Ops.LHS, Ops.RHS, "xor"); 289 } 290 Value *EmitOr (const BinOpInfo &Ops) { 291 return Builder.CreateOr(Ops.LHS, Ops.RHS, "or"); 292 } 293 294 BinOpInfo EmitBinOps(const BinaryOperator *E); 295 Value *EmitCompoundAssign(const CompoundAssignOperator *E, 296 Value *(ScalarExprEmitter::*F)(const BinOpInfo &)); 297 298 // Binary operators and binary compound assignment operators. 299#define HANDLEBINOP(OP) \ 300 Value *VisitBin ## OP(const BinaryOperator *E) { \ 301 return Emit ## OP(EmitBinOps(E)); \ 302 } \ 303 Value *VisitBin ## OP ## Assign(const CompoundAssignOperator *E) { \ 304 return EmitCompoundAssign(E, &ScalarExprEmitter::Emit ## OP); \ 305 } 306 HANDLEBINOP(Mul); 307 HANDLEBINOP(Div); 308 HANDLEBINOP(Rem); 309 HANDLEBINOP(Add); 310 HANDLEBINOP(Sub); 311 HANDLEBINOP(Shl); 312 HANDLEBINOP(Shr); 313 HANDLEBINOP(And); 314 HANDLEBINOP(Xor); 315 HANDLEBINOP(Or); 316#undef HANDLEBINOP 317 318 // Comparisons. 319 Value *EmitCompare(const BinaryOperator *E, unsigned UICmpOpc, 320 unsigned SICmpOpc, unsigned FCmpOpc); 321#define VISITCOMP(CODE, UI, SI, FP) \ 322 Value *VisitBin##CODE(const BinaryOperator *E) { \ 323 return EmitCompare(E, llvm::ICmpInst::UI, llvm::ICmpInst::SI, \ 324 llvm::FCmpInst::FP); } 325 VISITCOMP(LT, ICMP_ULT, ICMP_SLT, FCMP_OLT); 326 VISITCOMP(GT, ICMP_UGT, ICMP_SGT, FCMP_OGT); 327 VISITCOMP(LE, ICMP_ULE, ICMP_SLE, FCMP_OLE); 328 VISITCOMP(GE, ICMP_UGE, ICMP_SGE, FCMP_OGE); 329 VISITCOMP(EQ, ICMP_EQ , ICMP_EQ , FCMP_OEQ); 330 VISITCOMP(NE, ICMP_NE , ICMP_NE , FCMP_UNE); 331#undef VISITCOMP 332 333 Value *VisitBinAssign (const BinaryOperator *E); 334 335 Value *VisitBinLAnd (const BinaryOperator *E); 336 Value *VisitBinLOr (const BinaryOperator *E); 337 Value *VisitBinComma (const BinaryOperator *E); 338 339 // Other Operators. 340 Value *VisitBlockExpr(const BlockExpr *BE); 341 Value *VisitConditionalOperator(const ConditionalOperator *CO); 342 Value *VisitChooseExpr(ChooseExpr *CE); 343 Value *VisitVAArgExpr(VAArgExpr *VE); 344 Value *VisitObjCStringLiteral(const ObjCStringLiteral *E) { 345 return CGF.EmitObjCStringLiteral(E); 346 } 347}; 348} // end anonymous namespace. 349 350//===----------------------------------------------------------------------===// 351// Utilities 352//===----------------------------------------------------------------------===// 353 354/// EmitConversionToBool - Convert the specified expression value to a 355/// boolean (i1) truth value. This is equivalent to "Val != 0". 356Value *ScalarExprEmitter::EmitConversionToBool(Value *Src, QualType SrcType) { 357 assert(SrcType->isCanonical() && "EmitScalarConversion strips typedefs"); 358 359 if (SrcType->isRealFloatingType()) { 360 // Compare against 0.0 for fp scalars. 361 llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType()); 362 return Builder.CreateFCmpUNE(Src, Zero, "tobool"); 363 } 364 365 assert((SrcType->isIntegerType() || isa<llvm::PointerType>(Src->getType())) && 366 "Unknown scalar type to convert"); 367 368 // Because of the type rules of C, we often end up computing a logical value, 369 // then zero extending it to int, then wanting it as a logical value again. 370 // Optimize this common case. 371 if (llvm::ZExtInst *ZI = dyn_cast<llvm::ZExtInst>(Src)) { 372 if (ZI->getOperand(0)->getType() == llvm::Type::Int1Ty) { 373 Value *Result = ZI->getOperand(0); 374 // If there aren't any more uses, zap the instruction to save space. 375 // Note that there can be more uses, for example if this 376 // is the result of an assignment. 377 if (ZI->use_empty()) 378 ZI->eraseFromParent(); 379 return Result; 380 } 381 } 382 383 // Compare against an integer or pointer null. 384 llvm::Value *Zero = llvm::Constant::getNullValue(Src->getType()); 385 return Builder.CreateICmpNE(Src, Zero, "tobool"); 386} 387 388/// EmitScalarConversion - Emit a conversion from the specified type to the 389/// specified destination type, both of which are LLVM scalar types. 390Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType, 391 QualType DstType) { 392 SrcType = CGF.getContext().getCanonicalType(SrcType); 393 DstType = CGF.getContext().getCanonicalType(DstType); 394 if (SrcType == DstType) return Src; 395 396 if (DstType->isVoidType()) return 0; 397 398 // Handle conversions to bool first, they are special: comparisons against 0. 399 if (DstType->isBooleanType()) 400 return EmitConversionToBool(Src, SrcType); 401 402 const llvm::Type *DstTy = ConvertType(DstType); 403 404 // Ignore conversions like int -> uint. 405 if (Src->getType() == DstTy) 406 return Src; 407 408 // Handle pointer conversions next: pointers can only be converted 409 // to/from other pointers and integers. Check for pointer types in 410 // terms of LLVM, as some native types (like Obj-C id) may map to a 411 // pointer type. 412 if (isa<llvm::PointerType>(DstTy)) { 413 // The source value may be an integer, or a pointer. 414 if (isa<llvm::PointerType>(Src->getType())) 415 return Builder.CreateBitCast(Src, DstTy, "conv"); 416 assert(SrcType->isIntegerType() && "Not ptr->ptr or int->ptr conversion?"); 417 // First, convert to the correct width so that we control the kind of 418 // extension. 419 const llvm::Type *MiddleTy = llvm::IntegerType::get(CGF.LLVMPointerWidth); 420 bool InputSigned = SrcType->isSignedIntegerType(); 421 llvm::Value* IntResult = 422 Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv"); 423 // Then, cast to pointer. 424 return Builder.CreateIntToPtr(IntResult, DstTy, "conv"); 425 } 426 427 if (isa<llvm::PointerType>(Src->getType())) { 428 // Must be an ptr to int cast. 429 assert(isa<llvm::IntegerType>(DstTy) && "not ptr->int?"); 430 return Builder.CreatePtrToInt(Src, DstTy, "conv"); 431 } 432 433 // A scalar can be splatted to an extended vector of the same element type 434 if (DstType->isExtVectorType() && !isa<VectorType>(SrcType)) { 435 // Cast the scalar to element type 436 QualType EltTy = DstType->getAsExtVectorType()->getElementType(); 437 llvm::Value *Elt = EmitScalarConversion(Src, SrcType, EltTy); 438 439 // Insert the element in element zero of an undef vector 440 llvm::Value *UnV = llvm::UndefValue::get(DstTy); 441 llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, 0); 442 UnV = Builder.CreateInsertElement(UnV, Elt, Idx, "tmp"); 443 444 // Splat the element across to all elements 445 llvm::SmallVector<llvm::Constant*, 16> Args; 446 unsigned NumElements = cast<llvm::VectorType>(DstTy)->getNumElements(); 447 for (unsigned i = 0; i < NumElements; i++) 448 Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0)); 449 450 llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements); 451 llvm::Value *Yay = Builder.CreateShuffleVector(UnV, UnV, Mask, "splat"); 452 return Yay; 453 } 454 455 // Allow bitcast from vector to integer/fp of the same size. 456 if (isa<llvm::VectorType>(Src->getType()) || 457 isa<llvm::VectorType>(DstTy)) 458 return Builder.CreateBitCast(Src, DstTy, "conv"); 459 460 // Finally, we have the arithmetic types: real int/float. 461 if (isa<llvm::IntegerType>(Src->getType())) { 462 bool InputSigned = SrcType->isSignedIntegerType(); 463 if (isa<llvm::IntegerType>(DstTy)) 464 return Builder.CreateIntCast(Src, DstTy, InputSigned, "conv"); 465 else if (InputSigned) 466 return Builder.CreateSIToFP(Src, DstTy, "conv"); 467 else 468 return Builder.CreateUIToFP(Src, DstTy, "conv"); 469 } 470 471 assert(Src->getType()->isFloatingPoint() && "Unknown real conversion"); 472 if (isa<llvm::IntegerType>(DstTy)) { 473 if (DstType->isSignedIntegerType()) 474 return Builder.CreateFPToSI(Src, DstTy, "conv"); 475 else 476 return Builder.CreateFPToUI(Src, DstTy, "conv"); 477 } 478 479 assert(DstTy->isFloatingPoint() && "Unknown real conversion"); 480 if (DstTy->getTypeID() < Src->getType()->getTypeID()) 481 return Builder.CreateFPTrunc(Src, DstTy, "conv"); 482 else 483 return Builder.CreateFPExt(Src, DstTy, "conv"); 484} 485 486/// EmitComplexToScalarConversion - Emit a conversion from the specified 487/// complex type to the specified destination type, where the destination 488/// type is an LLVM scalar type. 489Value *ScalarExprEmitter:: 490EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src, 491 QualType SrcTy, QualType DstTy) { 492 // Get the source element type. 493 SrcTy = SrcTy->getAsComplexType()->getElementType(); 494 495 // Handle conversions to bool first, they are special: comparisons against 0. 496 if (DstTy->isBooleanType()) { 497 // Complex != 0 -> (Real != 0) | (Imag != 0) 498 Src.first = EmitScalarConversion(Src.first, SrcTy, DstTy); 499 Src.second = EmitScalarConversion(Src.second, SrcTy, DstTy); 500 return Builder.CreateOr(Src.first, Src.second, "tobool"); 501 } 502 503 // C99 6.3.1.7p2: "When a value of complex type is converted to a real type, 504 // the imaginary part of the complex value is discarded and the value of the 505 // real part is converted according to the conversion rules for the 506 // corresponding real type. 507 return EmitScalarConversion(Src.first, SrcTy, DstTy); 508} 509 510 511//===----------------------------------------------------------------------===// 512// Visitor Methods 513//===----------------------------------------------------------------------===// 514 515Value *ScalarExprEmitter::VisitExpr(Expr *E) { 516 CGF.ErrorUnsupported(E, "scalar expression"); 517 if (E->getType()->isVoidType()) 518 return 0; 519 return llvm::UndefValue::get(CGF.ConvertType(E->getType())); 520} 521 522Value *ScalarExprEmitter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) { 523 llvm::SmallVector<llvm::Constant*, 32> indices; 524 for (unsigned i = 2; i < E->getNumSubExprs(); i++) { 525 indices.push_back(cast<llvm::Constant>(CGF.EmitScalarExpr(E->getExpr(i)))); 526 } 527 Value* V1 = CGF.EmitScalarExpr(E->getExpr(0)); 528 Value* V2 = CGF.EmitScalarExpr(E->getExpr(1)); 529 Value* SV = llvm::ConstantVector::get(indices.begin(), indices.size()); 530 return Builder.CreateShuffleVector(V1, V2, SV, "shuffle"); 531} 532 533Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) { 534 // Emit subscript expressions in rvalue context's. For most cases, this just 535 // loads the lvalue formed by the subscript expr. However, we have to be 536 // careful, because the base of a vector subscript is occasionally an rvalue, 537 // so we can't get it as an lvalue. 538 if (!E->getBase()->getType()->isVectorType()) 539 return EmitLoadOfLValue(E); 540 541 // Handle the vector case. The base must be a vector, the index must be an 542 // integer value. 543 Value *Base = Visit(E->getBase()); 544 Value *Idx = Visit(E->getIdx()); 545 bool IdxSigned = E->getIdx()->getType()->isSignedIntegerType(); 546 Idx = Builder.CreateIntCast(Idx, llvm::Type::Int32Ty, IdxSigned, 547 "vecidxcast"); 548 return Builder.CreateExtractElement(Base, Idx, "vecext"); 549} 550 551/// VisitImplicitCastExpr - Implicit casts are the same as normal casts, but 552/// also handle things like function to pointer-to-function decay, and array to 553/// pointer decay. 554Value *ScalarExprEmitter::VisitImplicitCastExpr(const ImplicitCastExpr *E) { 555 const Expr *Op = E->getSubExpr(); 556 557 // If this is due to array->pointer conversion, emit the array expression as 558 // an l-value. 559 if (Op->getType()->isArrayType()) { 560 Value *V = EmitLValue(Op).getAddress(); // Bitfields can't be arrays. 561 562 // Note that VLA pointers are always decayed, so we don't need to do 563 // anything here. 564 if (!Op->getType()->isVariableArrayType()) { 565 assert(isa<llvm::PointerType>(V->getType()) && "Expected pointer"); 566 assert(isa<llvm::ArrayType>(cast<llvm::PointerType>(V->getType()) 567 ->getElementType()) && 568 "Expected pointer to array"); 569 V = Builder.CreateStructGEP(V, 0, "arraydecay"); 570 } 571 572 // The resultant pointer type can be implicitly casted to other pointer 573 // types as well (e.g. void*) and can be implicitly converted to integer. 574 const llvm::Type *DestTy = ConvertType(E->getType()); 575 if (V->getType() != DestTy) { 576 if (isa<llvm::PointerType>(DestTy)) 577 V = Builder.CreateBitCast(V, DestTy, "ptrconv"); 578 else { 579 assert(isa<llvm::IntegerType>(DestTy) && "Unknown array decay"); 580 V = Builder.CreatePtrToInt(V, DestTy, "ptrconv"); 581 } 582 } 583 return V; 584 } 585 586 return EmitCastExpr(Op, E->getType()); 587} 588 589 590// VisitCastExpr - Emit code for an explicit or implicit cast. Implicit casts 591// have to handle a more broad range of conversions than explicit casts, as they 592// handle things like function to ptr-to-function decay etc. 593Value *ScalarExprEmitter::EmitCastExpr(const Expr *E, QualType DestTy) { 594 // Handle cases where the source is an non-complex type. 595 596 if (!CGF.hasAggregateLLVMType(E->getType())) { 597 Value *Src = Visit(const_cast<Expr*>(E)); 598 599 // Use EmitScalarConversion to perform the conversion. 600 return EmitScalarConversion(Src, E->getType(), DestTy); 601 } 602 603 if (E->getType()->isAnyComplexType()) { 604 // Handle cases where the source is a complex type. 605 return EmitComplexToScalarConversion(CGF.EmitComplexExpr(E), E->getType(), 606 DestTy); 607 } 608 609 // Okay, this is a cast from an aggregate. It must be a cast to void. Just 610 // evaluate the result and return. 611 CGF.EmitAggExpr(E, 0, false); 612 return 0; 613} 614 615Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) { 616 return CGF.EmitCompoundStmt(*E->getSubStmt(), 617 !E->getType()->isVoidType()).getScalarVal(); 618} 619 620Value *ScalarExprEmitter::VisitBlockDeclRefExpr(const BlockDeclRefExpr *E) { 621 return Builder.CreateLoad(CGF.GetAddrOfBlockDecl(E), false, "tmp"); 622} 623 624//===----------------------------------------------------------------------===// 625// Unary Operators 626//===----------------------------------------------------------------------===// 627 628Value *ScalarExprEmitter::VisitPrePostIncDec(const UnaryOperator *E, 629 bool isInc, bool isPre) { 630 LValue LV = EmitLValue(E->getSubExpr()); 631 QualType ValTy = E->getSubExpr()->getType(); 632 Value *InVal = CGF.EmitLoadOfLValue(LV, ValTy).getScalarVal(); 633 634 int AmountVal = isInc ? 1 : -1; 635 636 if (ValTy->isPointerType() && 637 ValTy->getAsPointerType()->isVariableArrayType()) { 638 // The amount of the addition/subtraction needs to account for the VLA size 639 CGF.ErrorUnsupported(E, "VLA pointer inc/dec"); 640 } 641 642 Value *NextVal; 643 if (const llvm::PointerType *PT = 644 dyn_cast<llvm::PointerType>(InVal->getType())) { 645 llvm::Constant *Inc =llvm::ConstantInt::get(llvm::Type::Int32Ty, AmountVal); 646 if (!isa<llvm::FunctionType>(PT->getElementType())) { 647 NextVal = Builder.CreateGEP(InVal, Inc, "ptrincdec"); 648 } else { 649 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 650 NextVal = Builder.CreateBitCast(InVal, i8Ty, "tmp"); 651 NextVal = Builder.CreateGEP(NextVal, Inc, "ptrincdec"); 652 NextVal = Builder.CreateBitCast(NextVal, InVal->getType()); 653 } 654 } else if (InVal->getType() == llvm::Type::Int1Ty && isInc) { 655 // Bool++ is an interesting case, due to promotion rules, we get: 656 // Bool++ -> Bool = Bool+1 -> Bool = (int)Bool+1 -> 657 // Bool = ((int)Bool+1) != 0 658 // An interesting aspect of this is that increment is always true. 659 // Decrement does not have this property. 660 NextVal = llvm::ConstantInt::getTrue(); 661 } else { 662 // Add the inc/dec to the real part. 663 if (isa<llvm::IntegerType>(InVal->getType())) 664 NextVal = llvm::ConstantInt::get(InVal->getType(), AmountVal); 665 else if (InVal->getType() == llvm::Type::FloatTy) 666 NextVal = 667 llvm::ConstantFP::get(llvm::APFloat(static_cast<float>(AmountVal))); 668 else if (InVal->getType() == llvm::Type::DoubleTy) 669 NextVal = 670 llvm::ConstantFP::get(llvm::APFloat(static_cast<double>(AmountVal))); 671 else { 672 llvm::APFloat F(static_cast<float>(AmountVal)); 673 bool ignored; 674 F.convert(CGF.Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero, 675 &ignored); 676 NextVal = llvm::ConstantFP::get(F); 677 } 678 NextVal = Builder.CreateAdd(InVal, NextVal, isInc ? "inc" : "dec"); 679 } 680 681 // Store the updated result through the lvalue. 682 if (LV.isBitfield()) 683 CGF.EmitStoreThroughBitfieldLValue(RValue::get(NextVal), LV, ValTy, 684 &NextVal); 685 else 686 CGF.EmitStoreThroughLValue(RValue::get(NextVal), LV, ValTy); 687 688 // If this is a postinc, return the value read from memory, otherwise use the 689 // updated value. 690 return isPre ? NextVal : InVal; 691} 692 693 694Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) { 695 Value *Op = Visit(E->getSubExpr()); 696 return Builder.CreateNeg(Op, "neg"); 697} 698 699Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) { 700 Value *Op = Visit(E->getSubExpr()); 701 return Builder.CreateNot(Op, "neg"); 702} 703 704Value *ScalarExprEmitter::VisitUnaryLNot(const UnaryOperator *E) { 705 // Compare operand to zero. 706 Value *BoolVal = CGF.EvaluateExprAsBool(E->getSubExpr()); 707 708 // Invert value. 709 // TODO: Could dynamically modify easy computations here. For example, if 710 // the operand is an icmp ne, turn into icmp eq. 711 BoolVal = Builder.CreateNot(BoolVal, "lnot"); 712 713 // ZExt result to int. 714 return Builder.CreateZExt(BoolVal, CGF.LLVMIntTy, "lnot.ext"); 715} 716 717/// VisitSizeOfAlignOfExpr - Return the size or alignment of the type of 718/// argument of the sizeof expression as an integer. 719Value * 720ScalarExprEmitter::VisitSizeOfAlignOfExpr(const SizeOfAlignOfExpr *E) { 721 QualType TypeToSize = E->getTypeOfArgument(); 722 if (E->isSizeOf()) { 723 if (const VariableArrayType *VAT = 724 CGF.getContext().getAsVariableArrayType(TypeToSize)) { 725 if (E->isArgumentType()) { 726 // sizeof(type) - make sure to emit the VLA size. 727 CGF.EmitVLASize(TypeToSize); 728 } else { 729 // C99 6.5.3.4p2: If the argument is an expression of type 730 // VLA, it is evaluated. 731 CGF.EmitAnyExpr(E->getArgumentExpr()); 732 } 733 734 return CGF.GetVLASize(VAT); 735 } 736 } 737 738 // If this isn't sizeof(vla), the result must be constant; use the 739 // constant folding logic so we don't have to duplicate it here. 740 Expr::EvalResult Result; 741 E->Evaluate(Result, CGF.getContext()); 742 return llvm::ConstantInt::get(Result.Val.getInt()); 743} 744 745Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E) { 746 Expr *Op = E->getSubExpr(); 747 if (Op->getType()->isAnyComplexType()) 748 return CGF.EmitComplexExpr(Op).first; 749 return Visit(Op); 750} 751Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E) { 752 Expr *Op = E->getSubExpr(); 753 if (Op->getType()->isAnyComplexType()) 754 return CGF.EmitComplexExpr(Op).second; 755 756 // __imag on a scalar returns zero. Emit it the subexpr to ensure side 757 // effects are evaluated. 758 CGF.EmitScalarExpr(Op); 759 return llvm::Constant::getNullValue(ConvertType(E->getType())); 760} 761 762Value *ScalarExprEmitter::VisitUnaryOffsetOf(const UnaryOperator *E) 763{ 764 Value* ResultAsPtr = EmitLValue(E->getSubExpr()).getAddress(); 765 const llvm::Type* ResultType = ConvertType(E->getType()); 766 return Builder.CreatePtrToInt(ResultAsPtr, ResultType, "offsetof"); 767} 768 769//===----------------------------------------------------------------------===// 770// Binary Operators 771//===----------------------------------------------------------------------===// 772 773BinOpInfo ScalarExprEmitter::EmitBinOps(const BinaryOperator *E) { 774 BinOpInfo Result; 775 Result.LHS = Visit(E->getLHS()); 776 Result.RHS = Visit(E->getRHS()); 777 Result.Ty = E->getType(); 778 Result.E = E; 779 return Result; 780} 781 782Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E, 783 Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) { 784 QualType LHSTy = E->getLHS()->getType(), RHSTy = E->getRHS()->getType(); 785 786 BinOpInfo OpInfo; 787 788 if (E->getComputationResultType()->isAnyComplexType()) { 789 // This needs to go through the complex expression emitter, but 790 // it's a tad complicated to do that... I'm leaving it out for now. 791 // (Note that we do actually need the imaginary part of the RHS for 792 // multiplication and division.) 793 CGF.ErrorUnsupported(E, "complex compound assignment"); 794 return llvm::UndefValue::get(CGF.ConvertType(E->getType())); 795 } 796 797 // Load/convert the LHS. 798 LValue LHSLV = EmitLValue(E->getLHS()); 799 OpInfo.LHS = EmitLoadOfLValue(LHSLV, LHSTy); 800 OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy, 801 E->getComputationLHSType()); 802 // Emit the RHS. 803 OpInfo.RHS = Visit(E->getRHS()); 804 OpInfo.Ty = E->getComputationResultType(); 805 OpInfo.E = E; 806 807 // Expand the binary operator. 808 Value *Result = (this->*Func)(OpInfo); 809 810 // Convert the result back to the LHS type. 811 Result = EmitScalarConversion(Result, E->getComputationResultType(), LHSTy); 812 813 // Store the result value into the LHS lvalue. Bit-fields are 814 // handled specially because the result is altered by the store, 815 // i.e., [C99 6.5.16p1] 'An assignment expression has the value of 816 // the left operand after the assignment...'. 817 if (LHSLV.isBitfield()) 818 CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, LHSTy, 819 &Result); 820 else 821 CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV, LHSTy); 822 823 return Result; 824} 825 826 827Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) { 828 if (Ops.LHS->getType()->isFPOrFPVector()) 829 return Builder.CreateFDiv(Ops.LHS, Ops.RHS, "div"); 830 else if (Ops.Ty->isUnsignedIntegerType()) 831 return Builder.CreateUDiv(Ops.LHS, Ops.RHS, "div"); 832 else 833 return Builder.CreateSDiv(Ops.LHS, Ops.RHS, "div"); 834} 835 836Value *ScalarExprEmitter::EmitRem(const BinOpInfo &Ops) { 837 // Rem in C can't be a floating point type: C99 6.5.5p2. 838 if (Ops.Ty->isUnsignedIntegerType()) 839 return Builder.CreateURem(Ops.LHS, Ops.RHS, "rem"); 840 else 841 return Builder.CreateSRem(Ops.LHS, Ops.RHS, "rem"); 842} 843 844Value *ScalarExprEmitter::EmitOverflowCheckedBinOp(const BinOpInfo &Ops) { 845 unsigned IID; 846 unsigned OpID = 0; 847 848 switch (Ops.E->getOpcode()) { 849 case BinaryOperator::Add: 850 case BinaryOperator::AddAssign: 851 OpID = 1; 852 IID = llvm::Intrinsic::sadd_with_overflow; 853 break; 854 case BinaryOperator::Sub: 855 case BinaryOperator::SubAssign: 856 OpID = 2; 857 IID = llvm::Intrinsic::ssub_with_overflow; 858 break; 859 case BinaryOperator::Mul: 860 case BinaryOperator::MulAssign: 861 OpID = 3; 862 IID = llvm::Intrinsic::smul_with_overflow; 863 break; 864 default: 865 assert(false && "Unsupported operation for overflow detection"); 866 IID = 0; 867 } 868 OpID <<= 1; 869 OpID |= 1; 870 871 const llvm::Type *opTy = CGF.CGM.getTypes().ConvertType(Ops.Ty); 872 873 llvm::Function *intrinsic = CGF.CGM.getIntrinsic(IID, &opTy, 1); 874 875 Value *resultAndOverflow = Builder.CreateCall2(intrinsic, Ops.LHS, Ops.RHS); 876 Value *result = Builder.CreateExtractValue(resultAndOverflow, 0); 877 Value *overflow = Builder.CreateExtractValue(resultAndOverflow, 1); 878 879 // Branch in case of overflow. 880 llvm::BasicBlock *initialBB = Builder.GetInsertBlock(); 881 llvm::BasicBlock *overflowBB = 882 CGF.createBasicBlock("overflow", CGF.CurFn); 883 llvm::BasicBlock *continueBB = 884 CGF.createBasicBlock("overflow.continue", CGF.CurFn); 885 886 Builder.CreateCondBr(overflow, overflowBB, continueBB); 887 888 // Handle overflow 889 890 Builder.SetInsertPoint(overflowBB); 891 892 // Handler is: 893 // long long *__overflow_handler)(long long a, long long b, char op, 894 // char width) 895 std::vector<const llvm::Type*> handerArgTypes; 896 handerArgTypes.push_back(llvm::Type::Int64Ty); 897 handerArgTypes.push_back(llvm::Type::Int64Ty); 898 handerArgTypes.push_back(llvm::Type::Int8Ty); 899 handerArgTypes.push_back(llvm::Type::Int8Ty); 900 llvm::FunctionType *handlerTy = llvm::FunctionType::get(llvm::Type::Int64Ty, 901 handerArgTypes, false); 902 llvm::Value *handlerFunction = 903 CGF.CGM.getModule().getOrInsertGlobal("__overflow_handler", 904 llvm::PointerType::getUnqual(handlerTy)); 905 handlerFunction = Builder.CreateLoad(handlerFunction); 906 907 llvm::Value *handlerResult = Builder.CreateCall4(handlerFunction, 908 Builder.CreateSExt(Ops.LHS, llvm::Type::Int64Ty), 909 Builder.CreateSExt(Ops.RHS, llvm::Type::Int64Ty), 910 llvm::ConstantInt::get(llvm::Type::Int8Ty, OpID), 911 llvm::ConstantInt::get(llvm::Type::Int8Ty, 912 cast<llvm::IntegerType>(opTy)->getBitWidth())); 913 914 handlerResult = Builder.CreateTrunc(handlerResult, opTy); 915 916 Builder.CreateBr(continueBB); 917 918 // Set up the continuation 919 Builder.SetInsertPoint(continueBB); 920 // Get the correct result 921 llvm::PHINode *phi = Builder.CreatePHI(opTy); 922 phi->reserveOperandSpace(2); 923 phi->addIncoming(result, initialBB); 924 phi->addIncoming(handlerResult, overflowBB); 925 926 return phi; 927} 928 929Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &Ops) { 930 if (!Ops.Ty->isPointerType()) { 931 if (CGF.getContext().getLangOptions().OverflowChecking 932 && Ops.Ty->isSignedIntegerType()) 933 return EmitOverflowCheckedBinOp(Ops); 934 return Builder.CreateAdd(Ops.LHS, Ops.RHS, "add"); 935 } 936 937 if (Ops.Ty->getAsPointerType()->isVariableArrayType()) { 938 // The amount of the addition needs to account for the VLA size 939 CGF.ErrorUnsupported(Ops.E, "VLA pointer addition"); 940 } 941 Value *Ptr, *Idx; 942 Expr *IdxExp; 943 const PointerType *PT; 944 if ((PT = Ops.E->getLHS()->getType()->getAsPointerType())) { 945 Ptr = Ops.LHS; 946 Idx = Ops.RHS; 947 IdxExp = Ops.E->getRHS(); 948 } else { // int + pointer 949 PT = Ops.E->getRHS()->getType()->getAsPointerType(); 950 assert(PT && "Invalid add expr"); 951 Ptr = Ops.RHS; 952 Idx = Ops.LHS; 953 IdxExp = Ops.E->getLHS(); 954 } 955 956 unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth(); 957 // Only 32 and 64 are valid index widths. So if a target has shorter 958 // pointe width, extend to 32 at least. 959 unsigned IdxValidWidth 960 = (CGF.LLVMPointerWidth < 32) ? 32 : CGF.LLVMPointerWidth; 961 if (Width < IdxValidWidth) { 962 // Zero or sign extend the pointer value based on whether the index is 963 // signed or not. 964 const llvm::Type *IdxType = llvm::IntegerType::get(IdxValidWidth); 965 if (IdxExp->getType()->isSignedIntegerType()) 966 Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext"); 967 else 968 Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext"); 969 } 970 971 // Explicitly handle GNU void* and function pointer arithmetic 972 // extensions. The GNU void* casts amount to no-ops since our void* 973 // type is i8*, but this is future proof. 974 const QualType ElementType = PT->getPointeeType(); 975 if (ElementType->isVoidType() || ElementType->isFunctionType()) { 976 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 977 Value *Casted = Builder.CreateBitCast(Ptr, i8Ty); 978 Value *Res = Builder.CreateGEP(Casted, Idx, "sub.ptr"); 979 return Builder.CreateBitCast(Res, Ptr->getType()); 980 } 981 982 return Builder.CreateGEP(Ptr, Idx, "add.ptr"); 983} 984 985Value *ScalarExprEmitter::EmitSub(const BinOpInfo &Ops) { 986 if (!isa<llvm::PointerType>(Ops.LHS->getType())) { 987 if (CGF.getContext().getLangOptions().OverflowChecking 988 && Ops.Ty->isSignedIntegerType()) 989 return EmitOverflowCheckedBinOp(Ops); 990 return Builder.CreateSub(Ops.LHS, Ops.RHS, "sub"); 991 } 992 993 if (Ops.E->getLHS()->getType()->getAsPointerType()->isVariableArrayType()) { 994 // The amount of the addition needs to account for the VLA size for 995 // ptr-int 996 // The amount of the division needs to account for the VLA size for 997 // ptr-ptr. 998 CGF.ErrorUnsupported(Ops.E, "VLA pointer subtraction"); 999 } 1000 1001 const QualType LHSType = Ops.E->getLHS()->getType(); 1002 const QualType LHSElementType = LHSType->getAsPointerType()->getPointeeType(); 1003 if (!isa<llvm::PointerType>(Ops.RHS->getType())) { 1004 // pointer - int 1005 Value *Idx = Ops.RHS; 1006 unsigned Width = cast<llvm::IntegerType>(Idx->getType())->getBitWidth(); 1007 unsigned IdxValidWidth 1008 = (CGF.LLVMPointerWidth < 32) ? 32 : CGF.LLVMPointerWidth; 1009 if (Width < IdxValidWidth) { 1010 // Zero or sign extend the pointer value based on whether the index is 1011 // signed or not. 1012 const llvm::Type *IdxType = llvm::IntegerType::get(IdxValidWidth); 1013 if (Ops.E->getRHS()->getType()->isSignedIntegerType()) 1014 Idx = Builder.CreateSExt(Idx, IdxType, "idx.ext"); 1015 else 1016 Idx = Builder.CreateZExt(Idx, IdxType, "idx.ext"); 1017 } 1018 Idx = Builder.CreateNeg(Idx, "sub.ptr.neg"); 1019 1020 // Explicitly handle GNU void* and function pointer arithmetic 1021 // extensions. The GNU void* casts amount to no-ops since our 1022 // void* type is i8*, but this is future proof. 1023 if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) { 1024 const llvm::Type *i8Ty = llvm::PointerType::getUnqual(llvm::Type::Int8Ty); 1025 Value *LHSCasted = Builder.CreateBitCast(Ops.LHS, i8Ty); 1026 Value *Res = Builder.CreateGEP(LHSCasted, Idx, "sub.ptr"); 1027 return Builder.CreateBitCast(Res, Ops.LHS->getType()); 1028 } 1029 1030 return Builder.CreateGEP(Ops.LHS, Idx, "sub.ptr"); 1031 } else { 1032 // pointer - pointer 1033 Value *LHS = Ops.LHS; 1034 Value *RHS = Ops.RHS; 1035 1036 uint64_t ElementSize; 1037 1038 // Handle GCC extension for pointer arithmetic on void* and function pointer 1039 // types. 1040 if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) { 1041 ElementSize = 1; 1042 } else { 1043 ElementSize = CGF.getContext().getTypeSize(LHSElementType) / 8; 1044 } 1045 1046 const llvm::Type *ResultType = ConvertType(Ops.Ty); 1047 LHS = Builder.CreatePtrToInt(LHS, ResultType, "sub.ptr.lhs.cast"); 1048 RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast"); 1049 Value *BytesBetween = Builder.CreateSub(LHS, RHS, "sub.ptr.sub"); 1050 1051 // Optimize out the shift for element size of 1. 1052 if (ElementSize == 1) 1053 return BytesBetween; 1054 1055 // HACK: LLVM doesn't have an divide instruction that 'knows' there is no 1056 // remainder. As such, we handle common power-of-two cases here to generate 1057 // better code. See PR2247. 1058 if (llvm::isPowerOf2_64(ElementSize)) { 1059 Value *ShAmt = 1060 llvm::ConstantInt::get(ResultType, llvm::Log2_64(ElementSize)); 1061 return Builder.CreateAShr(BytesBetween, ShAmt, "sub.ptr.shr"); 1062 } 1063 1064 // Otherwise, do a full sdiv. 1065 Value *BytesPerElt = llvm::ConstantInt::get(ResultType, ElementSize); 1066 return Builder.CreateSDiv(BytesBetween, BytesPerElt, "sub.ptr.div"); 1067 } 1068} 1069 1070Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) { 1071 // LLVM requires the LHS and RHS to be the same type: promote or truncate the 1072 // RHS to the same size as the LHS. 1073 Value *RHS = Ops.RHS; 1074 if (Ops.LHS->getType() != RHS->getType()) 1075 RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); 1076 1077 return Builder.CreateShl(Ops.LHS, RHS, "shl"); 1078} 1079 1080Value *ScalarExprEmitter::EmitShr(const BinOpInfo &Ops) { 1081 // LLVM requires the LHS and RHS to be the same type: promote or truncate the 1082 // RHS to the same size as the LHS. 1083 Value *RHS = Ops.RHS; 1084 if (Ops.LHS->getType() != RHS->getType()) 1085 RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom"); 1086 1087 if (Ops.Ty->isUnsignedIntegerType()) 1088 return Builder.CreateLShr(Ops.LHS, RHS, "shr"); 1089 return Builder.CreateAShr(Ops.LHS, RHS, "shr"); 1090} 1091 1092Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,unsigned UICmpOpc, 1093 unsigned SICmpOpc, unsigned FCmpOpc) { 1094 Value *Result; 1095 QualType LHSTy = E->getLHS()->getType(); 1096 if (!LHSTy->isAnyComplexType() && !LHSTy->isVectorType()) { 1097 Value *LHS = Visit(E->getLHS()); 1098 Value *RHS = Visit(E->getRHS()); 1099 1100 if (LHS->getType()->isFloatingPoint()) { 1101 Result = Builder.CreateFCmp((llvm::CmpInst::Predicate)FCmpOpc, 1102 LHS, RHS, "cmp"); 1103 } else if (LHSTy->isSignedIntegerType()) { 1104 Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)SICmpOpc, 1105 LHS, RHS, "cmp"); 1106 } else { 1107 // Unsigned integers and pointers. 1108 Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1109 LHS, RHS, "cmp"); 1110 } 1111 } else if (LHSTy->isVectorType()) { 1112 Value *LHS = Visit(E->getLHS()); 1113 Value *RHS = Visit(E->getRHS()); 1114 1115 if (LHS->getType()->isFPOrFPVector()) { 1116 Result = Builder.CreateVFCmp((llvm::CmpInst::Predicate)FCmpOpc, 1117 LHS, RHS, "cmp"); 1118 } else if (LHSTy->isUnsignedIntegerType()) { 1119 Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)UICmpOpc, 1120 LHS, RHS, "cmp"); 1121 } else { 1122 // Signed integers and pointers. 1123 Result = Builder.CreateVICmp((llvm::CmpInst::Predicate)SICmpOpc, 1124 LHS, RHS, "cmp"); 1125 } 1126 return Result; 1127 } else { 1128 // Complex Comparison: can only be an equality comparison. 1129 CodeGenFunction::ComplexPairTy LHS = CGF.EmitComplexExpr(E->getLHS()); 1130 CodeGenFunction::ComplexPairTy RHS = CGF.EmitComplexExpr(E->getRHS()); 1131 1132 QualType CETy = LHSTy->getAsComplexType()->getElementType(); 1133 1134 Value *ResultR, *ResultI; 1135 if (CETy->isRealFloatingType()) { 1136 ResultR = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc, 1137 LHS.first, RHS.first, "cmp.r"); 1138 ResultI = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc, 1139 LHS.second, RHS.second, "cmp.i"); 1140 } else { 1141 // Complex comparisons can only be equality comparisons. As such, signed 1142 // and unsigned opcodes are the same. 1143 ResultR = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1144 LHS.first, RHS.first, "cmp.r"); 1145 ResultI = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc, 1146 LHS.second, RHS.second, "cmp.i"); 1147 } 1148 1149 if (E->getOpcode() == BinaryOperator::EQ) { 1150 Result = Builder.CreateAnd(ResultR, ResultI, "and.ri"); 1151 } else { 1152 assert(E->getOpcode() == BinaryOperator::NE && 1153 "Complex comparison other than == or != ?"); 1154 Result = Builder.CreateOr(ResultR, ResultI, "or.ri"); 1155 } 1156 } 1157 1158 return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType()); 1159} 1160 1161Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) { 1162 LValue LHS = EmitLValue(E->getLHS()); 1163 Value *RHS = Visit(E->getRHS()); 1164 1165 // Store the value into the LHS. Bit-fields are handled specially 1166 // because the result is altered by the store, i.e., [C99 6.5.16p1] 1167 // 'An assignment expression has the value of the left operand after 1168 // the assignment...'. 1169 if (LHS.isBitfield()) 1170 CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, E->getType(), 1171 &RHS); 1172 else 1173 CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS, E->getType()); 1174 1175 // Return the RHS. 1176 return RHS; 1177} 1178 1179Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) { 1180 // If we have 0 && RHS, see if we can elide RHS, if so, just return 0. 1181 // If we have 1 && X, just emit X without inserting the control flow. 1182 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) { 1183 if (Cond == 1) { // If we have 1 && X, just emit X. 1184 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1185 // ZExt result to int. 1186 return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "land.ext"); 1187 } 1188 1189 // 0 && RHS: If it is safe, just elide the RHS, and return 0. 1190 if (!CGF.ContainsLabel(E->getRHS())) 1191 return llvm::Constant::getNullValue(CGF.LLVMIntTy); 1192 } 1193 1194 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("land.end"); 1195 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("land.rhs"); 1196 1197 // Branch on the LHS first. If it is false, go to the failure (cont) block. 1198 CGF.EmitBranchOnBoolExpr(E->getLHS(), RHSBlock, ContBlock); 1199 1200 // Any edges into the ContBlock are now from an (indeterminate number of) 1201 // edges from this first condition. All of these values will be false. Start 1202 // setting up the PHI node in the Cont Block for this. 1203 llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::Int1Ty, "", ContBlock); 1204 PN->reserveOperandSpace(2); // Normal case, two inputs. 1205 for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); 1206 PI != PE; ++PI) 1207 PN->addIncoming(llvm::ConstantInt::getFalse(), *PI); 1208 1209 CGF.EmitBlock(RHSBlock); 1210 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1211 1212 // Reaquire the RHS block, as there may be subblocks inserted. 1213 RHSBlock = Builder.GetInsertBlock(); 1214 1215 // Emit an unconditional branch from this block to ContBlock. Insert an entry 1216 // into the phi node for the edge with the value of RHSCond. 1217 CGF.EmitBlock(ContBlock); 1218 PN->addIncoming(RHSCond, RHSBlock); 1219 1220 // ZExt result to int. 1221 return Builder.CreateZExt(PN, CGF.LLVMIntTy, "land.ext"); 1222} 1223 1224Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) { 1225 // If we have 1 || RHS, see if we can elide RHS, if so, just return 1. 1226 // If we have 0 || X, just emit X without inserting the control flow. 1227 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getLHS())) { 1228 if (Cond == -1) { // If we have 0 || X, just emit X. 1229 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1230 // ZExt result to int. 1231 return Builder.CreateZExt(RHSCond, CGF.LLVMIntTy, "lor.ext"); 1232 } 1233 1234 // 1 || RHS: If it is safe, just elide the RHS, and return 1. 1235 if (!CGF.ContainsLabel(E->getRHS())) 1236 return llvm::ConstantInt::get(CGF.LLVMIntTy, 1); 1237 } 1238 1239 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("lor.end"); 1240 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("lor.rhs"); 1241 1242 // Branch on the LHS first. If it is true, go to the success (cont) block. 1243 CGF.EmitBranchOnBoolExpr(E->getLHS(), ContBlock, RHSBlock); 1244 1245 // Any edges into the ContBlock are now from an (indeterminate number of) 1246 // edges from this first condition. All of these values will be true. Start 1247 // setting up the PHI node in the Cont Block for this. 1248 llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::Int1Ty, "", ContBlock); 1249 PN->reserveOperandSpace(2); // Normal case, two inputs. 1250 for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock); 1251 PI != PE; ++PI) 1252 PN->addIncoming(llvm::ConstantInt::getTrue(), *PI); 1253 1254 // Emit the RHS condition as a bool value. 1255 CGF.EmitBlock(RHSBlock); 1256 Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS()); 1257 1258 // Reaquire the RHS block, as there may be subblocks inserted. 1259 RHSBlock = Builder.GetInsertBlock(); 1260 1261 // Emit an unconditional branch from this block to ContBlock. Insert an entry 1262 // into the phi node for the edge with the value of RHSCond. 1263 CGF.EmitBlock(ContBlock); 1264 PN->addIncoming(RHSCond, RHSBlock); 1265 1266 // ZExt result to int. 1267 return Builder.CreateZExt(PN, CGF.LLVMIntTy, "lor.ext"); 1268} 1269 1270Value *ScalarExprEmitter::VisitBinComma(const BinaryOperator *E) { 1271 CGF.EmitStmt(E->getLHS()); 1272 CGF.EnsureInsertPoint(); 1273 return Visit(E->getRHS()); 1274} 1275 1276//===----------------------------------------------------------------------===// 1277// Other Operators 1278//===----------------------------------------------------------------------===// 1279 1280/// isCheapEnoughToEvaluateUnconditionally - Return true if the specified 1281/// expression is cheap enough and side-effect-free enough to evaluate 1282/// unconditionally instead of conditionally. This is used to convert control 1283/// flow into selects in some cases. 1284static bool isCheapEnoughToEvaluateUnconditionally(const Expr *E) { 1285 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) 1286 return isCheapEnoughToEvaluateUnconditionally(PE->getSubExpr()); 1287 1288 // TODO: Allow anything we can constant fold to an integer or fp constant. 1289 if (isa<IntegerLiteral>(E) || isa<CharacterLiteral>(E) || 1290 isa<FloatingLiteral>(E)) 1291 return true; 1292 1293 // Non-volatile automatic variables too, to get "cond ? X : Y" where 1294 // X and Y are local variables. 1295 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 1296 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) 1297 if (VD->hasLocalStorage() && !VD->getType().isVolatileQualified()) 1298 return true; 1299 1300 return false; 1301} 1302 1303 1304Value *ScalarExprEmitter:: 1305VisitConditionalOperator(const ConditionalOperator *E) { 1306 // If the condition constant folds and can be elided, try to avoid emitting 1307 // the condition and the dead arm. 1308 if (int Cond = CGF.ConstantFoldsToSimpleInteger(E->getCond())){ 1309 Expr *Live = E->getLHS(), *Dead = E->getRHS(); 1310 if (Cond == -1) 1311 std::swap(Live, Dead); 1312 1313 // If the dead side doesn't have labels we need, and if the Live side isn't 1314 // the gnu missing ?: extension (which we could handle, but don't bother 1315 // to), just emit the Live part. 1316 if ((!Dead || !CGF.ContainsLabel(Dead)) && // No labels in dead part 1317 Live) // Live part isn't missing. 1318 return Visit(Live); 1319 } 1320 1321 1322 // If this is a really simple expression (like x ? 4 : 5), emit this as a 1323 // select instead of as control flow. We can only do this if it is cheap and 1324 // safe to evaluate the LHS and RHS unconditionally. 1325 if (E->getLHS() && isCheapEnoughToEvaluateUnconditionally(E->getLHS()) && 1326 isCheapEnoughToEvaluateUnconditionally(E->getRHS())) { 1327 llvm::Value *CondV = CGF.EvaluateExprAsBool(E->getCond()); 1328 llvm::Value *LHS = Visit(E->getLHS()); 1329 llvm::Value *RHS = Visit(E->getRHS()); 1330 return Builder.CreateSelect(CondV, LHS, RHS, "cond"); 1331 } 1332 1333 1334 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true"); 1335 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false"); 1336 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end"); 1337 Value *CondVal = 0; 1338 1339 // If we don't have the GNU missing condition extension, emit a branch on 1340 // bool the normal way. 1341 if (E->getLHS()) { 1342 // Otherwise, just use EmitBranchOnBoolExpr to get small and simple code for 1343 // the branch on bool. 1344 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock); 1345 } else { 1346 // Otherwise, for the ?: extension, evaluate the conditional and then 1347 // convert it to bool the hard way. We do this explicitly because we need 1348 // the unconverted value for the missing middle value of the ?:. 1349 CondVal = CGF.EmitScalarExpr(E->getCond()); 1350 1351 // In some cases, EmitScalarConversion will delete the "CondVal" expression 1352 // if there are no extra uses (an optimization). Inhibit this by making an 1353 // extra dead use, because we're going to add a use of CondVal later. We 1354 // don't use the builder for this, because we don't want it to get optimized 1355 // away. This leaves dead code, but the ?: extension isn't common. 1356 new llvm::BitCastInst(CondVal, CondVal->getType(), "dummy?:holder", 1357 Builder.GetInsertBlock()); 1358 1359 Value *CondBoolVal = 1360 CGF.EmitScalarConversion(CondVal, E->getCond()->getType(), 1361 CGF.getContext().BoolTy); 1362 Builder.CreateCondBr(CondBoolVal, LHSBlock, RHSBlock); 1363 } 1364 1365 CGF.EmitBlock(LHSBlock); 1366 1367 // Handle the GNU extension for missing LHS. 1368 Value *LHS; 1369 if (E->getLHS()) 1370 LHS = Visit(E->getLHS()); 1371 else // Perform promotions, to handle cases like "short ?: int" 1372 LHS = EmitScalarConversion(CondVal, E->getCond()->getType(), E->getType()); 1373 1374 LHSBlock = Builder.GetInsertBlock(); 1375 CGF.EmitBranch(ContBlock); 1376 1377 CGF.EmitBlock(RHSBlock); 1378 1379 Value *RHS = Visit(E->getRHS()); 1380 RHSBlock = Builder.GetInsertBlock(); 1381 CGF.EmitBranch(ContBlock); 1382 1383 CGF.EmitBlock(ContBlock); 1384 1385 if (!LHS || !RHS) { 1386 assert(E->getType()->isVoidType() && "Non-void value should have a value"); 1387 return 0; 1388 } 1389 1390 // Create a PHI node for the real part. 1391 llvm::PHINode *PN = Builder.CreatePHI(LHS->getType(), "cond"); 1392 PN->reserveOperandSpace(2); 1393 PN->addIncoming(LHS, LHSBlock); 1394 PN->addIncoming(RHS, RHSBlock); 1395 return PN; 1396} 1397 1398Value *ScalarExprEmitter::VisitChooseExpr(ChooseExpr *E) { 1399 return Visit(E->getChosenSubExpr(CGF.getContext())); 1400} 1401 1402Value *ScalarExprEmitter::VisitVAArgExpr(VAArgExpr *VE) { 1403 llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr()); 1404 llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType()); 1405 1406 // If EmitVAArg fails, we fall back to the LLVM instruction. 1407 if (!ArgPtr) 1408 return Builder.CreateVAArg(ArgValue, ConvertType(VE->getType())); 1409 1410 return Builder.CreateLoad(ArgPtr); 1411} 1412 1413Value *ScalarExprEmitter::VisitBlockExpr(const BlockExpr *BE) { 1414 return CGF.BuildBlockLiteralTmp(BE); 1415} 1416 1417//===----------------------------------------------------------------------===// 1418// Entry Point into this File 1419//===----------------------------------------------------------------------===// 1420 1421/// EmitComplexExpr - Emit the computation of the specified expression of 1422/// complex type, ignoring the result. 1423Value *CodeGenFunction::EmitScalarExpr(const Expr *E) { 1424 assert(E && !hasAggregateLLVMType(E->getType()) && 1425 "Invalid scalar expression to emit"); 1426 1427 return ScalarExprEmitter(*this).Visit(const_cast<Expr*>(E)); 1428} 1429 1430/// EmitScalarConversion - Emit a conversion from the specified type to the 1431/// specified destination type, both of which are LLVM scalar types. 1432Value *CodeGenFunction::EmitScalarConversion(Value *Src, QualType SrcTy, 1433 QualType DstTy) { 1434 assert(!hasAggregateLLVMType(SrcTy) && !hasAggregateLLVMType(DstTy) && 1435 "Invalid scalar expression to emit"); 1436 return ScalarExprEmitter(*this).EmitScalarConversion(Src, SrcTy, DstTy); 1437} 1438 1439/// EmitComplexToScalarConversion - Emit a conversion from the specified 1440/// complex type to the specified destination type, where the destination 1441/// type is an LLVM scalar type. 1442Value *CodeGenFunction::EmitComplexToScalarConversion(ComplexPairTy Src, 1443 QualType SrcTy, 1444 QualType DstTy) { 1445 assert(SrcTy->isAnyComplexType() && !hasAggregateLLVMType(DstTy) && 1446 "Invalid complex -> scalar conversion"); 1447 return ScalarExprEmitter(*this).EmitComplexToScalarConversion(Src, SrcTy, 1448 DstTy); 1449} 1450 1451Value *CodeGenFunction::EmitShuffleVector(Value* V1, Value *V2, ...) { 1452 assert(V1->getType() == V2->getType() && 1453 "Vector operands must be of the same type"); 1454 unsigned NumElements = 1455 cast<llvm::VectorType>(V1->getType())->getNumElements(); 1456 1457 va_list va; 1458 va_start(va, V2); 1459 1460 llvm::SmallVector<llvm::Constant*, 16> Args; 1461 for (unsigned i = 0; i < NumElements; i++) { 1462 int n = va_arg(va, int); 1463 assert(n >= 0 && n < (int)NumElements * 2 && 1464 "Vector shuffle index out of bounds!"); 1465 Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, n)); 1466 } 1467 1468 const char *Name = va_arg(va, const char *); 1469 va_end(va); 1470 1471 llvm::Constant *Mask = llvm::ConstantVector::get(&Args[0], NumElements); 1472 1473 return Builder.CreateShuffleVector(V1, V2, Mask, Name); 1474} 1475 1476llvm::Value *CodeGenFunction::EmitVector(llvm::Value * const *Vals, 1477 unsigned NumVals, bool isSplat) { 1478 llvm::Value *Vec 1479 = llvm::UndefValue::get(llvm::VectorType::get(Vals[0]->getType(), NumVals)); 1480 1481 for (unsigned i = 0, e = NumVals; i != e; ++i) { 1482 llvm::Value *Val = isSplat ? Vals[0] : Vals[i]; 1483 llvm::Value *Idx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i); 1484 Vec = Builder.CreateInsertElement(Vec, Val, Idx, "tmp"); 1485 } 1486 1487 return Vec; 1488} 1489