ExprClassification.cpp revision ecea19f00a911c50dc20fe94e548f488ded47adb
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 // C++ [expr.typeid]p1: The result of a typeid expression is an lvalue of... 108 case Expr::CXXTypeidExprClass: 109 // Unresolved lookups get classified as lvalues. 110 // FIXME: Is this wise? Should they get their own kind? 111 case Expr::UnresolvedLookupExprClass: 112 case Expr::UnresolvedMemberExprClass: 113 case Expr::CXXDependentScopeMemberExprClass: 114 case Expr::CXXUnresolvedConstructExprClass: 115 case Expr::DependentScopeDeclRefExprClass: 116 // ObjC instance variables are lvalues 117 // FIXME: ObjC++0x might have different rules 118 case Expr::ObjCIvarRefExprClass: 119 return Cl::CL_LValue; 120 // C99 6.5.2.5p5 says that compound literals are lvalues. 121 // In C++, they're class temporaries. 122 case Expr::CompoundLiteralExprClass: 123 return Ctx.getLangOptions().CPlusPlus? Cl::CL_ClassTemporary 124 : Cl::CL_LValue; 125 126 // Expressions that are prvalues. 127 case Expr::CXXBoolLiteralExprClass: 128 case Expr::CXXPseudoDestructorExprClass: 129 case Expr::SizeOfAlignOfExprClass: 130 case Expr::CXXNewExprClass: 131 case Expr::CXXThisExprClass: 132 case Expr::CXXNullPtrLiteralExprClass: 133 case Expr::ImaginaryLiteralClass: 134 case Expr::GNUNullExprClass: 135 case Expr::OffsetOfExprClass: 136 case Expr::CXXThrowExprClass: 137 case Expr::ShuffleVectorExprClass: 138 case Expr::IntegerLiteralClass: 139 case Expr::CharacterLiteralClass: 140 case Expr::AddrLabelExprClass: 141 case Expr::CXXDeleteExprClass: 142 case Expr::ImplicitValueInitExprClass: 143 case Expr::BlockExprClass: 144 case Expr::FloatingLiteralClass: 145 case Expr::CXXNoexceptExprClass: 146 case Expr::CXXScalarValueInitExprClass: 147 case Expr::UnaryTypeTraitExprClass: 148 case Expr::BinaryTypeTraitExprClass: 149 case Expr::ObjCSelectorExprClass: 150 case Expr::ObjCProtocolExprClass: 151 case Expr::ObjCStringLiteralClass: 152 case Expr::ParenListExprClass: 153 case Expr::InitListExprClass: 154 return Cl::CL_PRValue; 155 156 // Next come the complicated cases. 157 158 // C++ [expr.sub]p1: The result is an lvalue of type "T". 159 // However, subscripting vector types is more like member access. 160 case Expr::ArraySubscriptExprClass: 161 if (cast<ArraySubscriptExpr>(E)->getBase()->getType()->isVectorType()) 162 return ClassifyInternal(Ctx, cast<ArraySubscriptExpr>(E)->getBase()); 163 return Cl::CL_LValue; 164 165 // C++ [expr.prim.general]p3: The result is an lvalue if the entity is a 166 // function or variable and a prvalue otherwise. 167 case Expr::DeclRefExprClass: 168 return ClassifyDecl(Ctx, cast<DeclRefExpr>(E)->getDecl()); 169 // We deal with names referenced from blocks the same way. 170 case Expr::BlockDeclRefExprClass: 171 return ClassifyDecl(Ctx, cast<BlockDeclRefExpr>(E)->getDecl()); 172 173 // Member access is complex. 174 case Expr::MemberExprClass: 175 return ClassifyMemberExpr(Ctx, cast<MemberExpr>(E)); 176 177 case Expr::UnaryOperatorClass: 178 switch (cast<UnaryOperator>(E)->getOpcode()) { 179 // C++ [expr.unary.op]p1: The unary * operator performs indirection: 180 // [...] the result is an lvalue referring to the object or function 181 // to which the expression points. 182 case UO_Deref: 183 return Cl::CL_LValue; 184 185 // GNU extensions, simply look through them. 186 case UO_Extension: 187 return ClassifyInternal(Ctx, cast<UnaryOperator>(E)->getSubExpr()); 188 189 // Treat _Real and _Imag basically as if they were member 190 // expressions: l-value only if the operand is a true l-value. 191 case UO_Real: 192 case UO_Imag: { 193 const Expr *Op = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens(); 194 Cl::Kinds K = ClassifyInternal(Ctx, Op); 195 if (K != Cl::CL_LValue) return K; 196 197 if (isa<ObjCPropertyRefExpr>(Op)) 198 return Cl::CL_SubObjCPropertySetting; 199 return Cl::CL_LValue; 200 } 201 202 // C++ [expr.pre.incr]p1: The result is the updated operand; it is an 203 // lvalue, [...] 204 // Not so in C. 205 case UO_PreInc: 206 case UO_PreDec: 207 return Lang.CPlusPlus ? Cl::CL_LValue : Cl::CL_PRValue; 208 209 default: 210 return Cl::CL_PRValue; 211 } 212 213 case Expr::OpaqueValueExprClass: 214 return ClassifyExprValueKind(Lang, E, 215 cast<OpaqueValueExpr>(E)->getValueKind()); 216 217 // Implicit casts are lvalues if they're lvalue casts. Other than that, we 218 // only specifically record class temporaries. 219 case Expr::ImplicitCastExprClass: 220 return ClassifyExprValueKind(Lang, E, 221 cast<ImplicitCastExpr>(E)->getValueKind()); 222 223 // C++ [expr.prim.general]p4: The presence of parentheses does not affect 224 // whether the expression is an lvalue. 225 case Expr::ParenExprClass: 226 return ClassifyInternal(Ctx, cast<ParenExpr>(E)->getSubExpr()); 227 228 case Expr::BinaryOperatorClass: 229 case Expr::CompoundAssignOperatorClass: 230 // C doesn't have any binary expressions that are lvalues. 231 if (Lang.CPlusPlus) 232 return ClassifyBinaryOp(Ctx, cast<BinaryOperator>(E)); 233 return Cl::CL_PRValue; 234 235 case Expr::CallExprClass: 236 case Expr::CXXOperatorCallExprClass: 237 case Expr::CXXMemberCallExprClass: 238 return ClassifyUnnamed(Ctx, cast<CallExpr>(E)->getCallReturnType()); 239 240 // __builtin_choose_expr is equivalent to the chosen expression. 241 case Expr::ChooseExprClass: 242 return ClassifyInternal(Ctx, cast<ChooseExpr>(E)->getChosenSubExpr(Ctx)); 243 244 // Extended vector element access is an lvalue unless there are duplicates 245 // in the shuffle expression. 246 case Expr::ExtVectorElementExprClass: 247 return cast<ExtVectorElementExpr>(E)->containsDuplicateElements() ? 248 Cl::CL_DuplicateVectorComponents : Cl::CL_LValue; 249 250 // Simply look at the actual default argument. 251 case Expr::CXXDefaultArgExprClass: 252 return ClassifyInternal(Ctx, cast<CXXDefaultArgExpr>(E)->getExpr()); 253 254 // Same idea for temporary binding. 255 case Expr::CXXBindTemporaryExprClass: 256 return ClassifyInternal(Ctx, cast<CXXBindTemporaryExpr>(E)->getSubExpr()); 257 258 // And the cleanups guard. 259 case Expr::ExprWithCleanupsClass: 260 return ClassifyInternal(Ctx, cast<ExprWithCleanups>(E)->getSubExpr()); 261 262 // Casts depend completely on the target type. All casts work the same. 263 case Expr::CStyleCastExprClass: 264 case Expr::CXXFunctionalCastExprClass: 265 case Expr::CXXStaticCastExprClass: 266 case Expr::CXXDynamicCastExprClass: 267 case Expr::CXXReinterpretCastExprClass: 268 case Expr::CXXConstCastExprClass: 269 // Only in C++ can casts be interesting at all. 270 if (!Lang.CPlusPlus) return Cl::CL_PRValue; 271 return ClassifyUnnamed(Ctx, cast<ExplicitCastExpr>(E)->getTypeAsWritten()); 272 273 case Expr::ConditionalOperatorClass: 274 // Once again, only C++ is interesting. 275 if (!Lang.CPlusPlus) return Cl::CL_PRValue; 276 return ClassifyConditional(Ctx, cast<ConditionalOperator>(E)); 277 278 // ObjC message sends are effectively function calls, if the target function 279 // is known. 280 case Expr::ObjCMessageExprClass: 281 if (const ObjCMethodDecl *Method = 282 cast<ObjCMessageExpr>(E)->getMethodDecl()) { 283 return ClassifyUnnamed(Ctx, Method->getResultType()); 284 } 285 return Cl::CL_PRValue; 286 287 // Some C++ expressions are always class temporaries. 288 case Expr::CXXConstructExprClass: 289 case Expr::CXXTemporaryObjectExprClass: 290 return Cl::CL_ClassTemporary; 291 292 case Expr::VAArgExprClass: 293 return ClassifyUnnamed(Ctx, E->getType()); 294 295 case Expr::DesignatedInitExprClass: 296 return ClassifyInternal(Ctx, cast<DesignatedInitExpr>(E)->getInit()); 297 298 case Expr::StmtExprClass: { 299 const CompoundStmt *S = cast<StmtExpr>(E)->getSubStmt(); 300 if (const Expr *LastExpr = dyn_cast_or_null<Expr>(S->body_back())) 301 return ClassifyUnnamed(Ctx, LastExpr->getType()); 302 return Cl::CL_PRValue; 303 } 304 305 case Expr::CXXUuidofExprClass: 306 return Cl::CL_LValue; 307 } 308 309 llvm_unreachable("unhandled expression kind in classification"); 310 return Cl::CL_LValue; 311} 312 313/// ClassifyDecl - Return the classification of an expression referencing the 314/// given declaration. 315static Cl::Kinds ClassifyDecl(ASTContext &Ctx, const Decl *D) { 316 // C++ [expr.prim.general]p6: The result is an lvalue if the entity is a 317 // function, variable, or data member and a prvalue otherwise. 318 // In C, functions are not lvalues. 319 // In addition, NonTypeTemplateParmDecl derives from VarDecl but isn't an 320 // lvalue unless it's a reference type (C++ [temp.param]p6), so we need to 321 // special-case this. 322 323 if (isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance()) 324 return Cl::CL_MemberFunction; 325 326 bool islvalue; 327 if (const NonTypeTemplateParmDecl *NTTParm = 328 dyn_cast<NonTypeTemplateParmDecl>(D)) 329 islvalue = NTTParm->getType()->isReferenceType(); 330 else 331 islvalue = isa<VarDecl>(D) || isa<FieldDecl>(D) || 332 isa<IndirectFieldDecl>(D) || 333 (Ctx.getLangOptions().CPlusPlus && 334 (isa<FunctionDecl>(D) || isa<FunctionTemplateDecl>(D))); 335 336 return islvalue ? Cl::CL_LValue : Cl::CL_PRValue; 337} 338 339/// ClassifyUnnamed - Return the classification of an expression yielding an 340/// unnamed value of the given type. This applies in particular to function 341/// calls and casts. 342static Cl::Kinds ClassifyUnnamed(ASTContext &Ctx, QualType T) { 343 // In C, function calls are always rvalues. 344 if (!Ctx.getLangOptions().CPlusPlus) return Cl::CL_PRValue; 345 346 // C++ [expr.call]p10: A function call is an lvalue if the result type is an 347 // lvalue reference type or an rvalue reference to function type, an xvalue 348 // if the result type is an rvalue refernence to object type, and a prvalue 349 // otherwise. 350 if (T->isLValueReferenceType()) 351 return Cl::CL_LValue; 352 const RValueReferenceType *RV = T->getAs<RValueReferenceType>(); 353 if (!RV) // Could still be a class temporary, though. 354 return T->isRecordType() ? Cl::CL_ClassTemporary : Cl::CL_PRValue; 355 356 return RV->getPointeeType()->isFunctionType() ? Cl::CL_LValue : Cl::CL_XValue; 357} 358 359static Cl::Kinds ClassifyMemberExpr(ASTContext &Ctx, const MemberExpr *E) { 360 // Handle C first, it's easier. 361 if (!Ctx.getLangOptions().CPlusPlus) { 362 // C99 6.5.2.3p3 363 // For dot access, the expression is an lvalue if the first part is. For 364 // arrow access, it always is an lvalue. 365 if (E->isArrow()) 366 return Cl::CL_LValue; 367 // ObjC property accesses are not lvalues, but get special treatment. 368 Expr *Base = E->getBase()->IgnoreParens(); 369 if (isa<ObjCPropertyRefExpr>(Base)) 370 return Cl::CL_SubObjCPropertySetting; 371 return ClassifyInternal(Ctx, Base); 372 } 373 374 NamedDecl *Member = E->getMemberDecl(); 375 // C++ [expr.ref]p3: E1->E2 is converted to the equivalent form (*(E1)).E2. 376 // C++ [expr.ref]p4: If E2 is declared to have type "reference to T", then 377 // E1.E2 is an lvalue. 378 if (ValueDecl *Value = dyn_cast<ValueDecl>(Member)) 379 if (Value->getType()->isReferenceType()) 380 return Cl::CL_LValue; 381 382 // Otherwise, one of the following rules applies. 383 // -- If E2 is a static member [...] then E1.E2 is an lvalue. 384 if (isa<VarDecl>(Member) && Member->getDeclContext()->isRecord()) 385 return Cl::CL_LValue; 386 387 // -- If E2 is a non-static data member [...]. If E1 is an lvalue, then 388 // E1.E2 is an lvalue; if E1 is an xvalue, then E1.E2 is an xvalue; 389 // otherwise, it is a prvalue. 390 if (isa<FieldDecl>(Member)) { 391 // *E1 is an lvalue 392 if (E->isArrow()) 393 return Cl::CL_LValue; 394 Expr *Base = E->getBase()->IgnoreParenImpCasts(); 395 if (isa<ObjCPropertyRefExpr>(Base)) 396 return Cl::CL_SubObjCPropertySetting; 397 return ClassifyInternal(Ctx, E->getBase()); 398 } 399 400 // -- If E2 is a [...] member function, [...] 401 // -- If it refers to a static member function [...], then E1.E2 is an 402 // lvalue; [...] 403 // -- Otherwise [...] E1.E2 is a prvalue. 404 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Member)) 405 return Method->isStatic() ? Cl::CL_LValue : Cl::CL_MemberFunction; 406 407 // -- If E2 is a member enumerator [...], the expression E1.E2 is a prvalue. 408 // So is everything else we haven't handled yet. 409 return Cl::CL_PRValue; 410} 411 412static Cl::Kinds ClassifyBinaryOp(ASTContext &Ctx, const BinaryOperator *E) { 413 assert(Ctx.getLangOptions().CPlusPlus && 414 "This is only relevant for C++."); 415 // C++ [expr.ass]p1: All [...] return an lvalue referring to the left operand. 416 // Except we override this for writes to ObjC properties. 417 if (E->isAssignmentOp()) 418 return (E->getLHS()->getObjectKind() == OK_ObjCProperty 419 ? Cl::CL_PRValue : Cl::CL_LValue); 420 421 // C++ [expr.comma]p1: the result is of the same value category as its right 422 // operand, [...]. 423 if (E->getOpcode() == BO_Comma) 424 return ClassifyInternal(Ctx, E->getRHS()); 425 426 // C++ [expr.mptr.oper]p6: The result of a .* expression whose second operand 427 // is a pointer to a data member is of the same value category as its first 428 // operand. 429 if (E->getOpcode() == BO_PtrMemD) 430 return E->getType()->isFunctionType() ? Cl::CL_MemberFunction : 431 ClassifyInternal(Ctx, E->getLHS()); 432 433 // C++ [expr.mptr.oper]p6: The result of an ->* expression is an lvalue if its 434 // second operand is a pointer to data member and a prvalue otherwise. 435 if (E->getOpcode() == BO_PtrMemI) 436 return E->getType()->isFunctionType() ? 437 Cl::CL_MemberFunction : Cl::CL_LValue; 438 439 // All other binary operations are prvalues. 440 return Cl::CL_PRValue; 441} 442 443static Cl::Kinds ClassifyConditional(ASTContext &Ctx, 444 const ConditionalOperator *E) { 445 assert(Ctx.getLangOptions().CPlusPlus && 446 "This is only relevant for C++."); 447 448 Expr *True = E->getTrueExpr(); 449 Expr *False = E->getFalseExpr(); 450 // C++ [expr.cond]p2 451 // If either the second or the third operand has type (cv) void, [...] 452 // the result [...] is a prvalue. 453 if (True->getType()->isVoidType() || False->getType()->isVoidType()) 454 return Cl::CL_PRValue; 455 456 // Note that at this point, we have already performed all conversions 457 // according to [expr.cond]p3. 458 // C++ [expr.cond]p4: If the second and third operands are glvalues of the 459 // same value category [...], the result is of that [...] value category. 460 // C++ [expr.cond]p5: Otherwise, the result is a prvalue. 461 Cl::Kinds LCl = ClassifyInternal(Ctx, True), 462 RCl = ClassifyInternal(Ctx, False); 463 return LCl == RCl ? LCl : Cl::CL_PRValue; 464} 465 466static Cl::ModifiableType IsModifiable(ASTContext &Ctx, const Expr *E, 467 Cl::Kinds Kind, SourceLocation &Loc) { 468 // As a general rule, we only care about lvalues. But there are some rvalues 469 // for which we want to generate special results. 470 if (Kind == Cl::CL_PRValue) { 471 // For the sake of better diagnostics, we want to specifically recognize 472 // use of the GCC cast-as-lvalue extension. 473 if (const ExplicitCastExpr *CE = 474 dyn_cast<ExplicitCastExpr>(E->IgnoreParens())) { 475 if (CE->getSubExpr()->IgnoreParenImpCasts()->isLValue()) { 476 Loc = CE->getExprLoc(); 477 return Cl::CM_LValueCast; 478 } 479 } 480 } 481 if (Kind != Cl::CL_LValue) 482 return Cl::CM_RValue; 483 484 // This is the lvalue case. 485 // Functions are lvalues in C++, but not modifiable. (C++ [basic.lval]p6) 486 if (Ctx.getLangOptions().CPlusPlus && E->getType()->isFunctionType()) 487 return Cl::CM_Function; 488 489 // You cannot assign to a variable outside a block from within the block if 490 // it is not marked __block, e.g. 491 // void takeclosure(void (^C)(void)); 492 // void func() { int x = 1; takeclosure(^{ x = 7; }); } 493 if (const BlockDeclRefExpr *BDR = dyn_cast<BlockDeclRefExpr>(E)) { 494 if (!BDR->isByRef() && isa<VarDecl>(BDR->getDecl())) 495 return Cl::CM_NotBlockQualified; 496 } 497 498 // Assignment to a property in ObjC is an implicit setter access. But a 499 // setter might not exist. 500 if (const ObjCPropertyRefExpr *Expr = dyn_cast<ObjCPropertyRefExpr>(E)) { 501 if (Expr->isImplicitProperty() && Expr->getImplicitPropertySetter() == 0) 502 return Cl::CM_NoSetterProperty; 503 } 504 505 CanQualType CT = Ctx.getCanonicalType(E->getType()); 506 // Const stuff is obviously not modifiable. 507 if (CT.isConstQualified()) 508 return Cl::CM_ConstQualified; 509 // Arrays are not modifiable, only their elements are. 510 if (CT->isArrayType()) 511 return Cl::CM_ArrayType; 512 // Incomplete types are not modifiable. 513 if (CT->isIncompleteType()) 514 return Cl::CM_IncompleteType; 515 516 // Records with any const fields (recursively) are not modifiable. 517 if (const RecordType *R = CT->getAs<RecordType>()) { 518 assert((E->getObjectKind() == OK_ObjCProperty || 519 !Ctx.getLangOptions().CPlusPlus) && 520 "C++ struct assignment should be resolved by the " 521 "copy assignment operator."); 522 if (R->hasConstFields()) 523 return Cl::CM_ConstQualified; 524 } 525 526 return Cl::CM_Modifiable; 527} 528 529Expr::LValueClassification Expr::ClassifyLValue(ASTContext &Ctx) const { 530 Classification VC = Classify(Ctx); 531 switch (VC.getKind()) { 532 case Cl::CL_LValue: return LV_Valid; 533 case Cl::CL_XValue: return LV_InvalidExpression; 534 case Cl::CL_Function: return LV_NotObjectType; 535 case Cl::CL_Void: return LV_IncompleteVoidType; 536 case Cl::CL_DuplicateVectorComponents: return LV_DuplicateVectorComponents; 537 case Cl::CL_MemberFunction: return LV_MemberFunction; 538 case Cl::CL_SubObjCPropertySetting: return LV_SubObjCPropertySetting; 539 case Cl::CL_ClassTemporary: return LV_ClassTemporary; 540 case Cl::CL_PRValue: return LV_InvalidExpression; 541 } 542 llvm_unreachable("Unhandled kind"); 543} 544 545Expr::isModifiableLvalueResult 546Expr::isModifiableLvalue(ASTContext &Ctx, SourceLocation *Loc) const { 547 SourceLocation dummy; 548 Classification VC = ClassifyModifiable(Ctx, Loc ? *Loc : dummy); 549 switch (VC.getKind()) { 550 case Cl::CL_LValue: break; 551 case Cl::CL_XValue: return MLV_InvalidExpression; 552 case Cl::CL_Function: return MLV_NotObjectType; 553 case Cl::CL_Void: return MLV_IncompleteVoidType; 554 case Cl::CL_DuplicateVectorComponents: return MLV_DuplicateVectorComponents; 555 case Cl::CL_MemberFunction: return MLV_MemberFunction; 556 case Cl::CL_SubObjCPropertySetting: return MLV_SubObjCPropertySetting; 557 case Cl::CL_ClassTemporary: return MLV_ClassTemporary; 558 case Cl::CL_PRValue: 559 return VC.getModifiable() == Cl::CM_LValueCast ? 560 MLV_LValueCast : MLV_InvalidExpression; 561 } 562 assert(VC.getKind() == Cl::CL_LValue && "Unhandled kind"); 563 switch (VC.getModifiable()) { 564 case Cl::CM_Untested: llvm_unreachable("Did not test modifiability"); 565 case Cl::CM_Modifiable: return MLV_Valid; 566 case Cl::CM_RValue: llvm_unreachable("CM_RValue and CL_LValue don't match"); 567 case Cl::CM_Function: return MLV_NotObjectType; 568 case Cl::CM_LValueCast: 569 llvm_unreachable("CM_LValueCast and CL_LValue don't match"); 570 case Cl::CM_NotBlockQualified: return MLV_NotBlockQualified; 571 case Cl::CM_NoSetterProperty: return MLV_NoSetterProperty; 572 case Cl::CM_ConstQualified: return MLV_ConstQualified; 573 case Cl::CM_ArrayType: return MLV_ArrayType; 574 case Cl::CM_IncompleteType: return MLV_IncompleteType; 575 } 576 llvm_unreachable("Unhandled modifiable type"); 577} 578