ExprClassification.cpp revision dfa1edbebeda7ec3a7a9c45e4317de9241aa9883
1//===--- ExprClassification.cpp - Expression AST Node Implementation ------===// 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 file implements Expr::classify. 11// 12//===----------------------------------------------------------------------===// 13 14#include "llvm/Support/ErrorHandling.h" 15#include "clang/AST/Expr.h" 16#include "clang/AST/ExprCXX.h" 17#include "clang/AST/ExprObjC.h" 18#include "clang/AST/ASTContext.h" 19#include "clang/AST/DeclObjC.h" 20#include "clang/AST/DeclCXX.h" 21#include "clang/AST/DeclTemplate.h" 22using namespace clang; 23 24typedef Expr::Classification Cl; 25 26static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E); 27static Cl::Kinds ClassifyDecl(ASTContext &Ctx, const Decl *D); 28static Cl::Kinds ClassifyUnnamed(ASTContext &Ctx, QualType T); 29static Cl::Kinds ClassifyMemberExpr(ASTContext &Ctx, const MemberExpr *E); 30static Cl::Kinds ClassifyBinaryOp(ASTContext &Ctx, const BinaryOperator *E); 31static Cl::Kinds ClassifyConditional(ASTContext &Ctx, 32 const ConditionalOperator *E); 33static Cl::ModifiableType IsModifiable(ASTContext &Ctx, const Expr *E, 34 Cl::Kinds Kind, SourceLocation &Loc); 35 36static Cl::Kinds ClassifyExprValueKind(const LangOptions &Lang, 37 const Expr *E, 38 ExprValueKind Kind) { 39 switch (Kind) { 40 case VK_RValue: 41 return Lang.CPlusPlus && E->getType()->isRecordType() ? 42 Cl::CL_ClassTemporary : Cl::CL_PRValue; 43 case VK_LValue: 44 return Cl::CL_LValue; 45 case VK_XValue: 46 return Cl::CL_XValue; 47 } 48 llvm_unreachable("Invalid value category of implicit cast."); 49 return Cl::CL_PRValue; 50} 51 52Cl Expr::ClassifyImpl(ASTContext &Ctx, SourceLocation *Loc) const { 53 assert(!TR->isReferenceType() && "Expressions can't have reference type."); 54 55 Cl::Kinds kind = ClassifyInternal(Ctx, this); 56 // C99 6.3.2.1: An lvalue is an expression with an object type or an 57 // incomplete type other than void. 58 if (!Ctx.getLangOptions().CPlusPlus) { 59 // Thus, no functions. 60 if (TR->isFunctionType() || TR == Ctx.OverloadTy) 61 kind = Cl::CL_Function; 62 // No void either, but qualified void is OK because it is "other than void". 63 else if (TR->isVoidType() && !Ctx.getCanonicalType(TR).hasQualifiers()) 64 kind = Cl::CL_Void; 65 } 66 67 // Enable this assertion for testing. 68 switch (kind) { 69 case Cl::CL_LValue: assert(getValueKind() == VK_LValue); break; 70 case Cl::CL_XValue: assert(getValueKind() == VK_XValue); break; 71 case Cl::CL_Function: 72 case Cl::CL_Void: 73 case Cl::CL_DuplicateVectorComponents: 74 case Cl::CL_MemberFunction: 75 case Cl::CL_SubObjCPropertySetting: 76 case Cl::CL_ClassTemporary: 77 case Cl::CL_PRValue: assert(getValueKind() == VK_RValue); break; 78 } 79 80 Cl::ModifiableType modifiable = Cl::CM_Untested; 81 if (Loc) 82 modifiable = IsModifiable(Ctx, this, kind, *Loc); 83 return Classification(kind, modifiable); 84} 85 86static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E) { 87 // This function takes the first stab at classifying expressions. 88 const LangOptions &Lang = Ctx.getLangOptions(); 89 90 switch (E->getStmtClass()) { 91 // First come the expressions that are always lvalues, unconditionally. 92 case Stmt::NoStmtClass: 93#define STMT(Kind, Base) case Expr::Kind##Class: 94#define EXPR(Kind, Base) 95#include "clang/AST/StmtNodes.inc" 96 llvm_unreachable("cannot classify a statement"); 97 break; 98 case Expr::ObjCIsaExprClass: 99 // C++ [expr.prim.general]p1: A string literal is an lvalue. 100 case Expr::StringLiteralClass: 101 // @encode is equivalent to its string 102 case Expr::ObjCEncodeExprClass: 103 // __func__ and friends are too. 104 case Expr::PredefinedExprClass: 105 // Property references are lvalues 106 case Expr::ObjCPropertyRefExprClass: 107 case Expr::ObjCImplicitSetterGetterRefExprClass: 108 // C++ [expr.typeid]p1: The result of a typeid expression is an lvalue of... 109 case Expr::CXXTypeidExprClass: 110 // Unresolved lookups get classified as lvalues. 111 // FIXME: Is this wise? Should they get their own kind? 112 case Expr::UnresolvedLookupExprClass: 113 case Expr::UnresolvedMemberExprClass: 114 case Expr::CXXDependentScopeMemberExprClass: 115 case Expr::CXXUnresolvedConstructExprClass: 116 case Expr::DependentScopeDeclRefExprClass: 117 // ObjC instance variables are lvalues 118 // FIXME: ObjC++0x might have different rules 119 case Expr::ObjCIvarRefExprClass: 120 return Cl::CL_LValue; 121 // C99 6.5.2.5p5 says that compound literals are lvalues. 122 // In C++, they're class temporaries. 123 case Expr::CompoundLiteralExprClass: 124 return Ctx.getLangOptions().CPlusPlus? Cl::CL_ClassTemporary 125 : Cl::CL_LValue; 126 127 // Expressions that are prvalues. 128 case Expr::CXXBoolLiteralExprClass: 129 case Expr::CXXPseudoDestructorExprClass: 130 case Expr::SizeOfAlignOfExprClass: 131 case Expr::CXXNewExprClass: 132 case Expr::CXXThisExprClass: 133 case Expr::CXXNullPtrLiteralExprClass: 134 case Expr::TypesCompatibleExprClass: 135 case Expr::ImaginaryLiteralClass: 136 case Expr::GNUNullExprClass: 137 case Expr::OffsetOfExprClass: 138 case Expr::CXXThrowExprClass: 139 case Expr::ShuffleVectorExprClass: 140 case Expr::IntegerLiteralClass: 141 case Expr::CharacterLiteralClass: 142 case Expr::AddrLabelExprClass: 143 case Expr::CXXDeleteExprClass: 144 case Expr::ImplicitValueInitExprClass: 145 case Expr::BlockExprClass: 146 case Expr::FloatingLiteralClass: 147 case Expr::CXXNoexceptExprClass: 148 case Expr::CXXScalarValueInitExprClass: 149 case Expr::UnaryTypeTraitExprClass: 150 case Expr::ObjCSelectorExprClass: 151 case Expr::ObjCProtocolExprClass: 152 case Expr::ObjCStringLiteralClass: 153 case Expr::ParenListExprClass: 154 case Expr::InitListExprClass: 155 return Cl::CL_PRValue; 156 157 // Next come the complicated cases. 158 159 // C++ [expr.sub]p1: The result is an lvalue of type "T". 160 // However, subscripting vector types is more like member access. 161 case Expr::ArraySubscriptExprClass: 162 if (cast<ArraySubscriptExpr>(E)->getBase()->getType()->isVectorType()) 163 return ClassifyInternal(Ctx, cast<ArraySubscriptExpr>(E)->getBase()); 164 return Cl::CL_LValue; 165 166 // C++ [expr.prim.general]p3: The result is an lvalue if the entity is a 167 // function or variable and a prvalue otherwise. 168 case Expr::DeclRefExprClass: 169 return ClassifyDecl(Ctx, cast<DeclRefExpr>(E)->getDecl()); 170 // We deal with names referenced from blocks the same way. 171 case Expr::BlockDeclRefExprClass: 172 return ClassifyDecl(Ctx, cast<BlockDeclRefExpr>(E)->getDecl()); 173 174 // Member access is complex. 175 case Expr::MemberExprClass: 176 return ClassifyMemberExpr(Ctx, cast<MemberExpr>(E)); 177 178 case Expr::UnaryOperatorClass: 179 switch (cast<UnaryOperator>(E)->getOpcode()) { 180 // C++ [expr.unary.op]p1: The unary * operator performs indirection: 181 // [...] the result is an lvalue referring to the object or function 182 // to which the expression points. 183 case UO_Deref: 184 return Cl::CL_LValue; 185 186 // GNU extensions, simply look through them. 187 case UO_Extension: 188 return ClassifyInternal(Ctx, cast<UnaryOperator>(E)->getSubExpr()); 189 190 // Treat _Real and _Imag basically as if they were member 191 // expressions: l-value only if the operand is a true l-value. 192 case UO_Real: 193 case UO_Imag: { 194 const Expr *Op = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens(); 195 Cl::Kinds K = ClassifyInternal(Ctx, Op); 196 if (K != Cl::CL_LValue) return K; 197 198 if (isa<ObjCPropertyRefExpr>(Op) || 199 isa<ObjCImplicitSetterGetterRefExpr>(Op)) 200 return Cl::CL_SubObjCPropertySetting; 201 return Cl::CL_LValue; 202 } 203 204 // C++ [expr.pre.incr]p1: The result is the updated operand; it is an 205 // lvalue, [...] 206 // Not so in C. 207 case UO_PreInc: 208 case UO_PreDec: 209 return Lang.CPlusPlus ? Cl::CL_LValue : Cl::CL_PRValue; 210 211 default: 212 return Cl::CL_PRValue; 213 } 214 215 case Expr::OpaqueValueExprClass: 216 return ClassifyExprValueKind(Lang, E, 217 cast<OpaqueValueExpr>(E)->getValueKind()); 218 219 // Implicit casts are lvalues if they're lvalue casts. Other than that, we 220 // only specifically record class temporaries. 221 case Expr::ImplicitCastExprClass: 222 return ClassifyExprValueKind(Lang, E, 223 cast<ImplicitCastExpr>(E)->getValueKind()); 224 225 // C++ [expr.prim.general]p4: The presence of parentheses does not affect 226 // whether the expression is an lvalue. 227 case Expr::ParenExprClass: 228 return ClassifyInternal(Ctx, cast<ParenExpr>(E)->getSubExpr()); 229 230 case Expr::BinaryOperatorClass: 231 case Expr::CompoundAssignOperatorClass: 232 // C doesn't have any binary expressions that are lvalues. 233 if (Lang.CPlusPlus) 234 return ClassifyBinaryOp(Ctx, cast<BinaryOperator>(E)); 235 return Cl::CL_PRValue; 236 237 case Expr::CallExprClass: 238 case Expr::CXXOperatorCallExprClass: 239 case Expr::CXXMemberCallExprClass: 240 return ClassifyUnnamed(Ctx, cast<CallExpr>(E)->getCallReturnType()); 241 242 // __builtin_choose_expr is equivalent to the chosen expression. 243 case Expr::ChooseExprClass: 244 return ClassifyInternal(Ctx, cast<ChooseExpr>(E)->getChosenSubExpr(Ctx)); 245 246 // Extended vector element access is an lvalue unless there are duplicates 247 // in the shuffle expression. 248 case Expr::ExtVectorElementExprClass: 249 return cast<ExtVectorElementExpr>(E)->containsDuplicateElements() ? 250 Cl::CL_DuplicateVectorComponents : Cl::CL_LValue; 251 252 // Simply look at the actual default argument. 253 case Expr::CXXDefaultArgExprClass: 254 return ClassifyInternal(Ctx, cast<CXXDefaultArgExpr>(E)->getExpr()); 255 256 // Same idea for temporary binding. 257 case Expr::CXXBindTemporaryExprClass: 258 return ClassifyInternal(Ctx, cast<CXXBindTemporaryExpr>(E)->getSubExpr()); 259 260 // And the temporary lifetime guard. 261 case Expr::CXXExprWithTemporariesClass: 262 return ClassifyInternal(Ctx, cast<CXXExprWithTemporaries>(E)->getSubExpr()); 263 264 // Casts depend completely on the target type. All casts work the same. 265 case Expr::CStyleCastExprClass: 266 case Expr::CXXFunctionalCastExprClass: 267 case Expr::CXXStaticCastExprClass: 268 case Expr::CXXDynamicCastExprClass: 269 case Expr::CXXReinterpretCastExprClass: 270 case Expr::CXXConstCastExprClass: 271 // Only in C++ can casts be interesting at all. 272 if (!Lang.CPlusPlus) return Cl::CL_PRValue; 273 return ClassifyUnnamed(Ctx, cast<ExplicitCastExpr>(E)->getTypeAsWritten()); 274 275 case Expr::ConditionalOperatorClass: 276 // Once again, only C++ is interesting. 277 if (!Lang.CPlusPlus) return Cl::CL_PRValue; 278 return ClassifyConditional(Ctx, cast<ConditionalOperator>(E)); 279 280 // ObjC message sends are effectively function calls, if the target function 281 // is known. 282 case Expr::ObjCMessageExprClass: 283 if (const ObjCMethodDecl *Method = 284 cast<ObjCMessageExpr>(E)->getMethodDecl()) { 285 return ClassifyUnnamed(Ctx, Method->getResultType()); 286 } 287 return Cl::CL_PRValue; 288 289 // Some C++ expressions are always class temporaries. 290 case Expr::CXXConstructExprClass: 291 case Expr::CXXTemporaryObjectExprClass: 292 return Cl::CL_ClassTemporary; 293 294 case Expr::VAArgExprClass: 295 return ClassifyUnnamed(Ctx, E->getType()); 296 297 case Expr::DesignatedInitExprClass: 298 return ClassifyInternal(Ctx, cast<DesignatedInitExpr>(E)->getInit()); 299 300 case Expr::StmtExprClass: { 301 const CompoundStmt *S = cast<StmtExpr>(E)->getSubStmt(); 302 if (const Expr *LastExpr = dyn_cast_or_null<Expr>(S->body_back())) 303 return ClassifyUnnamed(Ctx, LastExpr->getType()); 304 return Cl::CL_PRValue; 305 } 306 307 case Expr::CXXUuidofExprClass: 308 return Cl::CL_PRValue; 309 } 310 311 llvm_unreachable("unhandled expression kind in classification"); 312 return Cl::CL_LValue; 313} 314 315/// ClassifyDecl - Return the classification of an expression referencing the 316/// given declaration. 317static Cl::Kinds ClassifyDecl(ASTContext &Ctx, const Decl *D) { 318 // C++ [expr.prim.general]p6: The result is an lvalue if the entity is a 319 // function, variable, or data member and a prvalue otherwise. 320 // In C, functions are not lvalues. 321 // In addition, NonTypeTemplateParmDecl derives from VarDecl but isn't an 322 // lvalue unless it's a reference type (C++ [temp.param]p6), so we need to 323 // special-case this. 324 325 if (isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance()) 326 return Cl::CL_MemberFunction; 327 328 bool islvalue; 329 if (const NonTypeTemplateParmDecl *NTTParm = 330 dyn_cast<NonTypeTemplateParmDecl>(D)) 331 islvalue = NTTParm->getType()->isReferenceType(); 332 else 333 islvalue = isa<VarDecl>(D) || isa<FieldDecl>(D) || 334 isa<IndirectFieldDecl>(D) || 335 (Ctx.getLangOptions().CPlusPlus && 336 (isa<FunctionDecl>(D) || isa<FunctionTemplateDecl>(D))); 337 338 return islvalue ? Cl::CL_LValue : Cl::CL_PRValue; 339} 340 341/// ClassifyUnnamed - Return the classification of an expression yielding an 342/// unnamed value of the given type. This applies in particular to function 343/// calls and casts. 344static Cl::Kinds ClassifyUnnamed(ASTContext &Ctx, QualType T) { 345 // In C, function calls are always rvalues. 346 if (!Ctx.getLangOptions().CPlusPlus) return Cl::CL_PRValue; 347 348 // C++ [expr.call]p10: A function call is an lvalue if the result type is an 349 // lvalue reference type or an rvalue reference to function type, an xvalue 350 // if the result type is an rvalue refernence to object type, and a prvalue 351 // otherwise. 352 if (T->isLValueReferenceType()) 353 return Cl::CL_LValue; 354 const RValueReferenceType *RV = T->getAs<RValueReferenceType>(); 355 if (!RV) // Could still be a class temporary, though. 356 return T->isRecordType() ? Cl::CL_ClassTemporary : Cl::CL_PRValue; 357 358 return RV->getPointeeType()->isFunctionType() ? Cl::CL_LValue : Cl::CL_XValue; 359} 360 361static Cl::Kinds ClassifyMemberExpr(ASTContext &Ctx, const MemberExpr *E) { 362 // Handle C first, it's easier. 363 if (!Ctx.getLangOptions().CPlusPlus) { 364 // C99 6.5.2.3p3 365 // For dot access, the expression is an lvalue if the first part is. For 366 // arrow access, it always is an lvalue. 367 if (E->isArrow()) 368 return Cl::CL_LValue; 369 // ObjC property accesses are not lvalues, but get special treatment. 370 Expr *Base = E->getBase()->IgnoreParens(); 371 if (isa<ObjCPropertyRefExpr>(Base) || 372 isa<ObjCImplicitSetterGetterRefExpr>(Base)) 373 return Cl::CL_SubObjCPropertySetting; 374 return ClassifyInternal(Ctx, Base); 375 } 376 377 NamedDecl *Member = E->getMemberDecl(); 378 // C++ [expr.ref]p3: E1->E2 is converted to the equivalent form (*(E1)).E2. 379 // C++ [expr.ref]p4: If E2 is declared to have type "reference to T", then 380 // E1.E2 is an lvalue. 381 if (ValueDecl *Value = dyn_cast<ValueDecl>(Member)) 382 if (Value->getType()->isReferenceType()) 383 return Cl::CL_LValue; 384 385 // Otherwise, one of the following rules applies. 386 // -- If E2 is a static member [...] then E1.E2 is an lvalue. 387 if (isa<VarDecl>(Member) && Member->getDeclContext()->isRecord()) 388 return Cl::CL_LValue; 389 390 // -- If E2 is a non-static data member [...]. If E1 is an lvalue, then 391 // E1.E2 is an lvalue; if E1 is an xvalue, then E1.E2 is an xvalue; 392 // otherwise, it is a prvalue. 393 if (isa<FieldDecl>(Member)) { 394 // *E1 is an lvalue 395 if (E->isArrow()) 396 return Cl::CL_LValue; 397 Expr *Base = E->getBase()->IgnoreParenImpCasts(); 398 if (isa<ObjCPropertyRefExpr>(Base) || 399 isa<ObjCImplicitSetterGetterRefExpr>(Base)) 400 return Cl::CL_SubObjCPropertySetting; 401 return ClassifyInternal(Ctx, E->getBase()); 402 } 403 404 // -- If E2 is a [...] member function, [...] 405 // -- If it refers to a static member function [...], then E1.E2 is an 406 // lvalue; [...] 407 // -- Otherwise [...] E1.E2 is a prvalue. 408 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Member)) 409 return Method->isStatic() ? Cl::CL_LValue : Cl::CL_MemberFunction; 410 411 // -- If E2 is a member enumerator [...], the expression E1.E2 is a prvalue. 412 // So is everything else we haven't handled yet. 413 return Cl::CL_PRValue; 414} 415 416static Cl::Kinds ClassifyBinaryOp(ASTContext &Ctx, const BinaryOperator *E) { 417 assert(Ctx.getLangOptions().CPlusPlus && 418 "This is only relevant for C++."); 419 // C++ [expr.ass]p1: All [...] return an lvalue referring to the left operand. 420 if (E->isAssignmentOp()) 421 return Cl::CL_LValue; 422 423 // C++ [expr.comma]p1: the result is of the same value category as its right 424 // operand, [...]. 425 if (E->getOpcode() == BO_Comma) 426 return ClassifyInternal(Ctx, E->getRHS()); 427 428 // C++ [expr.mptr.oper]p6: The result of a .* expression whose second operand 429 // is a pointer to a data member is of the same value category as its first 430 // operand. 431 if (E->getOpcode() == BO_PtrMemD) 432 return E->getType()->isFunctionType() ? Cl::CL_MemberFunction : 433 ClassifyInternal(Ctx, E->getLHS()); 434 435 // C++ [expr.mptr.oper]p6: The result of an ->* expression is an lvalue if its 436 // second operand is a pointer to data member and a prvalue otherwise. 437 if (E->getOpcode() == BO_PtrMemI) 438 return E->getType()->isFunctionType() ? 439 Cl::CL_MemberFunction : Cl::CL_LValue; 440 441 // All other binary operations are prvalues. 442 return Cl::CL_PRValue; 443} 444 445static Cl::Kinds ClassifyConditional(ASTContext &Ctx, 446 const ConditionalOperator *E) { 447 assert(Ctx.getLangOptions().CPlusPlus && 448 "This is only relevant for C++."); 449 450 Expr *True = E->getTrueExpr(); 451 Expr *False = E->getFalseExpr(); 452 // C++ [expr.cond]p2 453 // If either the second or the third operand has type (cv) void, [...] 454 // the result [...] is a prvalue. 455 if (True->getType()->isVoidType() || False->getType()->isVoidType()) 456 return Cl::CL_PRValue; 457 458 // Note that at this point, we have already performed all conversions 459 // according to [expr.cond]p3. 460 // C++ [expr.cond]p4: If the second and third operands are glvalues of the 461 // same value category [...], the result is of that [...] value category. 462 // C++ [expr.cond]p5: Otherwise, the result is a prvalue. 463 Cl::Kinds LCl = ClassifyInternal(Ctx, True), 464 RCl = ClassifyInternal(Ctx, False); 465 return LCl == RCl ? LCl : Cl::CL_PRValue; 466} 467 468static Cl::ModifiableType IsModifiable(ASTContext &Ctx, const Expr *E, 469 Cl::Kinds Kind, SourceLocation &Loc) { 470 // As a general rule, we only care about lvalues. But there are some rvalues 471 // for which we want to generate special results. 472 if (Kind == Cl::CL_PRValue) { 473 // For the sake of better diagnostics, we want to specifically recognize 474 // use of the GCC cast-as-lvalue extension. 475 if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E->IgnoreParens())){ 476 if (CE->getSubExpr()->Classify(Ctx).isLValue()) { 477 Loc = CE->getLParenLoc(); 478 return Cl::CM_LValueCast; 479 } 480 } 481 } 482 if (Kind != Cl::CL_LValue) 483 return Cl::CM_RValue; 484 485 // This is the lvalue case. 486 // Functions are lvalues in C++, but not modifiable. (C++ [basic.lval]p6) 487 if (Ctx.getLangOptions().CPlusPlus && E->getType()->isFunctionType()) 488 return Cl::CM_Function; 489 490 // You cannot assign to a variable outside a block from within the block if 491 // it is not marked __block, e.g. 492 // void takeclosure(void (^C)(void)); 493 // void func() { int x = 1; takeclosure(^{ x = 7; }); } 494 if (const BlockDeclRefExpr *BDR = dyn_cast<BlockDeclRefExpr>(E)) { 495 if (!BDR->isByRef() && isa<VarDecl>(BDR->getDecl())) 496 return Cl::CM_NotBlockQualified; 497 } 498 499 // Assignment to a property in ObjC is an implicit setter access. But a 500 // setter might not exist. 501 if (const ObjCImplicitSetterGetterRefExpr *Expr = 502 dyn_cast<ObjCImplicitSetterGetterRefExpr>(E)) { 503 if (Expr->getSetterMethod() == 0) 504 return Cl::CM_NoSetterProperty; 505 } 506 507 CanQualType CT = Ctx.getCanonicalType(E->getType()); 508 // Const stuff is obviously not modifiable. 509 if (CT.isConstQualified()) 510 return Cl::CM_ConstQualified; 511 // Arrays are not modifiable, only their elements are. 512 if (CT->isArrayType()) 513 return Cl::CM_ArrayType; 514 // Incomplete types are not modifiable. 515 if (CT->isIncompleteType()) 516 return Cl::CM_IncompleteType; 517 518 // Records with any const fields (recursively) are not modifiable. 519 if (const RecordType *R = CT->getAs<RecordType>()) { 520 assert((isa<ObjCImplicitSetterGetterRefExpr>(E) || 521 isa<ObjCPropertyRefExpr>(E) || 522 !Ctx.getLangOptions().CPlusPlus) && 523 "C++ struct assignment should be resolved by the " 524 "copy assignment operator."); 525 if (R->hasConstFields()) 526 return Cl::CM_ConstQualified; 527 } 528 529 return Cl::CM_Modifiable; 530} 531 532Expr::isLvalueResult Expr::isLvalue(ASTContext &Ctx) const { 533 Classification VC = Classify(Ctx); 534 switch (VC.getKind()) { 535 case Cl::CL_LValue: return LV_Valid; 536 case Cl::CL_XValue: return LV_InvalidExpression; 537 case Cl::CL_Function: return LV_NotObjectType; 538 case Cl::CL_Void: return LV_IncompleteVoidType; 539 case Cl::CL_DuplicateVectorComponents: return LV_DuplicateVectorComponents; 540 case Cl::CL_MemberFunction: return LV_MemberFunction; 541 case Cl::CL_SubObjCPropertySetting: return LV_SubObjCPropertySetting; 542 case Cl::CL_ClassTemporary: return LV_ClassTemporary; 543 case Cl::CL_PRValue: return LV_InvalidExpression; 544 } 545 llvm_unreachable("Unhandled kind"); 546} 547 548Expr::isModifiableLvalueResult 549Expr::isModifiableLvalue(ASTContext &Ctx, SourceLocation *Loc) const { 550 SourceLocation dummy; 551 Classification VC = ClassifyModifiable(Ctx, Loc ? *Loc : dummy); 552 switch (VC.getKind()) { 553 case Cl::CL_LValue: break; 554 case Cl::CL_XValue: return MLV_InvalidExpression; 555 case Cl::CL_Function: return MLV_NotObjectType; 556 case Cl::CL_Void: return MLV_IncompleteVoidType; 557 case Cl::CL_DuplicateVectorComponents: return MLV_DuplicateVectorComponents; 558 case Cl::CL_MemberFunction: return MLV_MemberFunction; 559 case Cl::CL_SubObjCPropertySetting: return MLV_SubObjCPropertySetting; 560 case Cl::CL_ClassTemporary: return MLV_ClassTemporary; 561 case Cl::CL_PRValue: 562 return VC.getModifiable() == Cl::CM_LValueCast ? 563 MLV_LValueCast : MLV_InvalidExpression; 564 } 565 assert(VC.getKind() == Cl::CL_LValue && "Unhandled kind"); 566 switch (VC.getModifiable()) { 567 case Cl::CM_Untested: llvm_unreachable("Did not test modifiability"); 568 case Cl::CM_Modifiable: return MLV_Valid; 569 case Cl::CM_RValue: llvm_unreachable("CM_RValue and CL_LValue don't match"); 570 case Cl::CM_Function: return MLV_NotObjectType; 571 case Cl::CM_LValueCast: 572 llvm_unreachable("CM_LValueCast and CL_LValue don't match"); 573 case Cl::CM_NotBlockQualified: return MLV_NotBlockQualified; 574 case Cl::CM_NoSetterProperty: return MLV_NoSetterProperty; 575 case Cl::CM_ConstQualified: return MLV_ConstQualified; 576 case Cl::CM_ArrayType: return MLV_ArrayType; 577 case Cl::CM_IncompleteType: return MLV_IncompleteType; 578 } 579 llvm_unreachable("Unhandled modifiable type"); 580} 581