ExprConstant.cpp revision 86c3ae46250cdcc57778c27826060779a92f3815
1//===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===// 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 the Expr constant evaluator. 11// 12// Constant expression evaluation produces four main results: 13// 14// * A success/failure flag indicating whether constant folding was successful. 15// This is the 'bool' return value used by most of the code in this file. A 16// 'false' return value indicates that constant folding has failed, and any 17// appropriate diagnostic has already been produced. 18// 19// * An evaluated result, valid only if constant folding has not failed. 20// 21// * A flag indicating if evaluation encountered (unevaluated) side-effects. 22// These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1), 23// where it is possible to determine the evaluated result regardless. 24// 25// * A set of notes indicating why the evaluation was not a constant expression 26// (under the C++11 rules only, at the moment), or, if folding failed too, 27// why the expression could not be folded. 28// 29// If we are checking for a potential constant expression, failure to constant 30// fold a potential constant sub-expression will be indicated by a 'false' 31// return value (the expression could not be folded) and no diagnostic (the 32// expression is not necessarily non-constant). 33// 34//===----------------------------------------------------------------------===// 35 36#include "clang/AST/APValue.h" 37#include "clang/AST/ASTContext.h" 38#include "clang/AST/CharUnits.h" 39#include "clang/AST/RecordLayout.h" 40#include "clang/AST/StmtVisitor.h" 41#include "clang/AST/TypeLoc.h" 42#include "clang/AST/ASTDiagnostic.h" 43#include "clang/AST/Expr.h" 44#include "clang/Basic/Builtins.h" 45#include "clang/Basic/TargetInfo.h" 46#include "llvm/ADT/SmallString.h" 47#include <cstring> 48#include <functional> 49 50using namespace clang; 51using llvm::APSInt; 52using llvm::APFloat; 53 54/// EvalInfo - This is a private struct used by the evaluator to capture 55/// information about a subexpression as it is folded. It retains information 56/// about the AST context, but also maintains information about the folded 57/// expression. 58/// 59/// If an expression could be evaluated, it is still possible it is not a C 60/// "integer constant expression" or constant expression. If not, this struct 61/// captures information about how and why not. 62/// 63/// One bit of information passed *into* the request for constant folding 64/// indicates whether the subexpression is "evaluated" or not according to C 65/// rules. For example, the RHS of (0 && foo()) is not evaluated. We can 66/// evaluate the expression regardless of what the RHS is, but C only allows 67/// certain things in certain situations. 68namespace { 69 struct LValue; 70 struct CallStackFrame; 71 struct EvalInfo; 72 73 QualType getType(APValue::LValueBase B) { 74 if (!B) return QualType(); 75 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) 76 return D->getType(); 77 return B.get<const Expr*>()->getType(); 78 } 79 80 /// Get an LValue path entry, which is known to not be an array index, as a 81 /// field or base class. 82 APValue::BaseOrMemberType getAsBaseOrMember(APValue::LValuePathEntry E) { 83 APValue::BaseOrMemberType Value; 84 Value.setFromOpaqueValue(E.BaseOrMember); 85 return Value; 86 } 87 88 /// Get an LValue path entry, which is known to not be an array index, as a 89 /// field declaration. 90 const FieldDecl *getAsField(APValue::LValuePathEntry E) { 91 return dyn_cast<FieldDecl>(getAsBaseOrMember(E).getPointer()); 92 } 93 /// Get an LValue path entry, which is known to not be an array index, as a 94 /// base class declaration. 95 const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) { 96 return dyn_cast<CXXRecordDecl>(getAsBaseOrMember(E).getPointer()); 97 } 98 /// Determine whether this LValue path entry for a base class names a virtual 99 /// base class. 100 bool isVirtualBaseClass(APValue::LValuePathEntry E) { 101 return getAsBaseOrMember(E).getInt(); 102 } 103 104 /// Find the path length and type of the most-derived subobject in the given 105 /// path, and find the size of the containing array, if any. 106 static 107 unsigned findMostDerivedSubobject(ASTContext &Ctx, QualType Base, 108 ArrayRef<APValue::LValuePathEntry> Path, 109 uint64_t &ArraySize, QualType &Type) { 110 unsigned MostDerivedLength = 0; 111 Type = Base; 112 for (unsigned I = 0, N = Path.size(); I != N; ++I) { 113 if (Type->isArrayType()) { 114 const ConstantArrayType *CAT = 115 cast<ConstantArrayType>(Ctx.getAsArrayType(Type)); 116 Type = CAT->getElementType(); 117 ArraySize = CAT->getSize().getZExtValue(); 118 MostDerivedLength = I + 1; 119 } else if (const FieldDecl *FD = getAsField(Path[I])) { 120 Type = FD->getType(); 121 ArraySize = 0; 122 MostDerivedLength = I + 1; 123 } else { 124 // Path[I] describes a base class. 125 ArraySize = 0; 126 } 127 } 128 return MostDerivedLength; 129 } 130 131 // The order of this enum is important for diagnostics. 132 enum CheckSubobjectKind { 133 CSK_Base, CSK_Derived, CSK_Field, CSK_ArrayToPointer, CSK_ArrayIndex, 134 CSK_This 135 }; 136 137 /// A path from a glvalue to a subobject of that glvalue. 138 struct SubobjectDesignator { 139 /// True if the subobject was named in a manner not supported by C++11. Such 140 /// lvalues can still be folded, but they are not core constant expressions 141 /// and we cannot perform lvalue-to-rvalue conversions on them. 142 bool Invalid : 1; 143 144 /// Is this a pointer one past the end of an object? 145 bool IsOnePastTheEnd : 1; 146 147 /// The length of the path to the most-derived object of which this is a 148 /// subobject. 149 unsigned MostDerivedPathLength : 30; 150 151 /// The size of the array of which the most-derived object is an element, or 152 /// 0 if the most-derived object is not an array element. 153 uint64_t MostDerivedArraySize; 154 155 /// The type of the most derived object referred to by this address. 156 QualType MostDerivedType; 157 158 typedef APValue::LValuePathEntry PathEntry; 159 160 /// The entries on the path from the glvalue to the designated subobject. 161 SmallVector<PathEntry, 8> Entries; 162 163 SubobjectDesignator() : Invalid(true) {} 164 165 explicit SubobjectDesignator(QualType T) 166 : Invalid(false), IsOnePastTheEnd(false), MostDerivedPathLength(0), 167 MostDerivedArraySize(0), MostDerivedType(T) {} 168 169 SubobjectDesignator(ASTContext &Ctx, const APValue &V) 170 : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false), 171 MostDerivedPathLength(0), MostDerivedArraySize(0) { 172 if (!Invalid) { 173 IsOnePastTheEnd = V.isLValueOnePastTheEnd(); 174 ArrayRef<PathEntry> VEntries = V.getLValuePath(); 175 Entries.insert(Entries.end(), VEntries.begin(), VEntries.end()); 176 if (V.getLValueBase()) 177 MostDerivedPathLength = 178 findMostDerivedSubobject(Ctx, getType(V.getLValueBase()), 179 V.getLValuePath(), MostDerivedArraySize, 180 MostDerivedType); 181 } 182 } 183 184 void setInvalid() { 185 Invalid = true; 186 Entries.clear(); 187 } 188 189 /// Determine whether this is a one-past-the-end pointer. 190 bool isOnePastTheEnd() const { 191 if (IsOnePastTheEnd) 192 return true; 193 if (MostDerivedArraySize && 194 Entries[MostDerivedPathLength - 1].ArrayIndex == MostDerivedArraySize) 195 return true; 196 return false; 197 } 198 199 /// Check that this refers to a valid subobject. 200 bool isValidSubobject() const { 201 if (Invalid) 202 return false; 203 return !isOnePastTheEnd(); 204 } 205 /// Check that this refers to a valid subobject, and if not, produce a 206 /// relevant diagnostic and set the designator as invalid. 207 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK); 208 209 /// Update this designator to refer to the first element within this array. 210 void addArrayUnchecked(const ConstantArrayType *CAT) { 211 PathEntry Entry; 212 Entry.ArrayIndex = 0; 213 Entries.push_back(Entry); 214 215 // This is a most-derived object. 216 MostDerivedType = CAT->getElementType(); 217 MostDerivedArraySize = CAT->getSize().getZExtValue(); 218 MostDerivedPathLength = Entries.size(); 219 } 220 /// Update this designator to refer to the given base or member of this 221 /// object. 222 void addDeclUnchecked(const Decl *D, bool Virtual = false) { 223 PathEntry Entry; 224 APValue::BaseOrMemberType Value(D, Virtual); 225 Entry.BaseOrMember = Value.getOpaqueValue(); 226 Entries.push_back(Entry); 227 228 // If this isn't a base class, it's a new most-derived object. 229 if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) { 230 MostDerivedType = FD->getType(); 231 MostDerivedArraySize = 0; 232 MostDerivedPathLength = Entries.size(); 233 } 234 } 235 void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E, uint64_t N); 236 /// Add N to the address of this subobject. 237 void adjustIndex(EvalInfo &Info, const Expr *E, uint64_t N) { 238 if (Invalid) return; 239 if (MostDerivedPathLength == Entries.size() && MostDerivedArraySize) { 240 Entries.back().ArrayIndex += N; 241 if (Entries.back().ArrayIndex > MostDerivedArraySize) { 242 diagnosePointerArithmetic(Info, E, Entries.back().ArrayIndex); 243 setInvalid(); 244 } 245 return; 246 } 247 // [expr.add]p4: For the purposes of these operators, a pointer to a 248 // nonarray object behaves the same as a pointer to the first element of 249 // an array of length one with the type of the object as its element type. 250 if (IsOnePastTheEnd && N == (uint64_t)-1) 251 IsOnePastTheEnd = false; 252 else if (!IsOnePastTheEnd && N == 1) 253 IsOnePastTheEnd = true; 254 else if (N != 0) { 255 diagnosePointerArithmetic(Info, E, uint64_t(IsOnePastTheEnd) + N); 256 setInvalid(); 257 } 258 } 259 }; 260 261 /// A core constant value. This can be the value of any constant expression, 262 /// or a pointer or reference to a non-static object or function parameter. 263 /// 264 /// For an LValue, the base and offset are stored in the APValue subobject, 265 /// but the other information is stored in the SubobjectDesignator. For all 266 /// other value kinds, the value is stored directly in the APValue subobject. 267 class CCValue : public APValue { 268 typedef llvm::APSInt APSInt; 269 typedef llvm::APFloat APFloat; 270 /// If the value is a reference or pointer into a parameter or temporary, 271 /// this is the corresponding call stack frame. 272 CallStackFrame *CallFrame; 273 /// If the value is a reference or pointer, this is a description of how the 274 /// subobject was specified. 275 SubobjectDesignator Designator; 276 public: 277 struct GlobalValue {}; 278 279 CCValue() {} 280 explicit CCValue(const APSInt &I) : APValue(I) {} 281 explicit CCValue(const APFloat &F) : APValue(F) {} 282 CCValue(const APValue *E, unsigned N) : APValue(E, N) {} 283 CCValue(const APSInt &R, const APSInt &I) : APValue(R, I) {} 284 CCValue(const APFloat &R, const APFloat &I) : APValue(R, I) {} 285 CCValue(const CCValue &V) : APValue(V), CallFrame(V.CallFrame) {} 286 CCValue(LValueBase B, const CharUnits &O, CallStackFrame *F, 287 const SubobjectDesignator &D) : 288 APValue(B, O, APValue::NoLValuePath()), CallFrame(F), Designator(D) {} 289 CCValue(ASTContext &Ctx, const APValue &V, GlobalValue) : 290 APValue(V), CallFrame(0), Designator(Ctx, V) {} 291 CCValue(const ValueDecl *D, bool IsDerivedMember, 292 ArrayRef<const CXXRecordDecl*> Path) : 293 APValue(D, IsDerivedMember, Path) {} 294 CCValue(const AddrLabelExpr* LHSExpr, const AddrLabelExpr* RHSExpr) : 295 APValue(LHSExpr, RHSExpr) {} 296 297 CallStackFrame *getLValueFrame() const { 298 assert(getKind() == LValue); 299 return CallFrame; 300 } 301 SubobjectDesignator &getLValueDesignator() { 302 assert(getKind() == LValue); 303 return Designator; 304 } 305 const SubobjectDesignator &getLValueDesignator() const { 306 return const_cast<CCValue*>(this)->getLValueDesignator(); 307 } 308 }; 309 310 /// A stack frame in the constexpr call stack. 311 struct CallStackFrame { 312 EvalInfo &Info; 313 314 /// Parent - The caller of this stack frame. 315 CallStackFrame *Caller; 316 317 /// CallLoc - The location of the call expression for this call. 318 SourceLocation CallLoc; 319 320 /// Callee - The function which was called. 321 const FunctionDecl *Callee; 322 323 /// This - The binding for the this pointer in this call, if any. 324 const LValue *This; 325 326 /// ParmBindings - Parameter bindings for this function call, indexed by 327 /// parameters' function scope indices. 328 const CCValue *Arguments; 329 330 typedef llvm::DenseMap<const Expr*, CCValue> MapTy; 331 typedef MapTy::const_iterator temp_iterator; 332 /// Temporaries - Temporary lvalues materialized within this stack frame. 333 MapTy Temporaries; 334 335 CallStackFrame(EvalInfo &Info, SourceLocation CallLoc, 336 const FunctionDecl *Callee, const LValue *This, 337 const CCValue *Arguments); 338 ~CallStackFrame(); 339 }; 340 341 /// A partial diagnostic which we might know in advance that we are not going 342 /// to emit. 343 class OptionalDiagnostic { 344 PartialDiagnostic *Diag; 345 346 public: 347 explicit OptionalDiagnostic(PartialDiagnostic *Diag = 0) : Diag(Diag) {} 348 349 template<typename T> 350 OptionalDiagnostic &operator<<(const T &v) { 351 if (Diag) 352 *Diag << v; 353 return *this; 354 } 355 356 OptionalDiagnostic &operator<<(const APSInt &I) { 357 if (Diag) { 358 llvm::SmallVector<char, 32> Buffer; 359 I.toString(Buffer); 360 *Diag << StringRef(Buffer.data(), Buffer.size()); 361 } 362 return *this; 363 } 364 365 OptionalDiagnostic &operator<<(const APFloat &F) { 366 if (Diag) { 367 llvm::SmallVector<char, 32> Buffer; 368 F.toString(Buffer); 369 *Diag << StringRef(Buffer.data(), Buffer.size()); 370 } 371 return *this; 372 } 373 }; 374 375 struct EvalInfo { 376 ASTContext &Ctx; 377 378 /// EvalStatus - Contains information about the evaluation. 379 Expr::EvalStatus &EvalStatus; 380 381 /// CurrentCall - The top of the constexpr call stack. 382 CallStackFrame *CurrentCall; 383 384 /// CallStackDepth - The number of calls in the call stack right now. 385 unsigned CallStackDepth; 386 387 typedef llvm::DenseMap<const OpaqueValueExpr*, CCValue> MapTy; 388 /// OpaqueValues - Values used as the common expression in a 389 /// BinaryConditionalOperator. 390 MapTy OpaqueValues; 391 392 /// BottomFrame - The frame in which evaluation started. This must be 393 /// initialized after CurrentCall and CallStackDepth. 394 CallStackFrame BottomFrame; 395 396 /// EvaluatingDecl - This is the declaration whose initializer is being 397 /// evaluated, if any. 398 const VarDecl *EvaluatingDecl; 399 400 /// EvaluatingDeclValue - This is the value being constructed for the 401 /// declaration whose initializer is being evaluated, if any. 402 APValue *EvaluatingDeclValue; 403 404 /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further 405 /// notes attached to it will also be stored, otherwise they will not be. 406 bool HasActiveDiagnostic; 407 408 /// CheckingPotentialConstantExpression - Are we checking whether the 409 /// expression is a potential constant expression? If so, some diagnostics 410 /// are suppressed. 411 bool CheckingPotentialConstantExpression; 412 413 414 EvalInfo(const ASTContext &C, Expr::EvalStatus &S) 415 : Ctx(const_cast<ASTContext&>(C)), EvalStatus(S), CurrentCall(0), 416 CallStackDepth(0), BottomFrame(*this, SourceLocation(), 0, 0, 0), 417 EvaluatingDecl(0), EvaluatingDeclValue(0), HasActiveDiagnostic(false), 418 CheckingPotentialConstantExpression(false) {} 419 420 const CCValue *getOpaqueValue(const OpaqueValueExpr *e) const { 421 MapTy::const_iterator i = OpaqueValues.find(e); 422 if (i == OpaqueValues.end()) return 0; 423 return &i->second; 424 } 425 426 void setEvaluatingDecl(const VarDecl *VD, APValue &Value) { 427 EvaluatingDecl = VD; 428 EvaluatingDeclValue = &Value; 429 } 430 431 const LangOptions &getLangOpts() const { return Ctx.getLangOptions(); } 432 433 bool CheckCallLimit(SourceLocation Loc) { 434 // Don't perform any constexpr calls (other than the call we're checking) 435 // when checking a potential constant expression. 436 if (CheckingPotentialConstantExpression && CallStackDepth > 1) 437 return false; 438 if (CallStackDepth <= getLangOpts().ConstexprCallDepth) 439 return true; 440 Diag(Loc, diag::note_constexpr_depth_limit_exceeded) 441 << getLangOpts().ConstexprCallDepth; 442 return false; 443 } 444 445 private: 446 /// Add a diagnostic to the diagnostics list. 447 PartialDiagnostic &addDiag(SourceLocation Loc, diag::kind DiagId) { 448 PartialDiagnostic PD(DiagId, Ctx.getDiagAllocator()); 449 EvalStatus.Diag->push_back(std::make_pair(Loc, PD)); 450 return EvalStatus.Diag->back().second; 451 } 452 453 /// Add notes containing a call stack to the current point of evaluation. 454 void addCallStack(unsigned Limit); 455 456 public: 457 /// Diagnose that the evaluation cannot be folded. 458 OptionalDiagnostic Diag(SourceLocation Loc, diag::kind DiagId 459 = diag::note_invalid_subexpr_in_const_expr, 460 unsigned ExtraNotes = 0) { 461 // If we have a prior diagnostic, it will be noting that the expression 462 // isn't a constant expression. This diagnostic is more important. 463 // FIXME: We might want to show both diagnostics to the user. 464 if (EvalStatus.Diag) { 465 unsigned CallStackNotes = CallStackDepth - 1; 466 unsigned Limit = Ctx.getDiagnostics().getConstexprBacktraceLimit(); 467 if (Limit) 468 CallStackNotes = std::min(CallStackNotes, Limit + 1); 469 if (CheckingPotentialConstantExpression) 470 CallStackNotes = 0; 471 472 HasActiveDiagnostic = true; 473 EvalStatus.Diag->clear(); 474 EvalStatus.Diag->reserve(1 + ExtraNotes + CallStackNotes); 475 addDiag(Loc, DiagId); 476 if (!CheckingPotentialConstantExpression) 477 addCallStack(Limit); 478 return OptionalDiagnostic(&(*EvalStatus.Diag)[0].second); 479 } 480 HasActiveDiagnostic = false; 481 return OptionalDiagnostic(); 482 } 483 484 /// Diagnose that the evaluation does not produce a C++11 core constant 485 /// expression. 486 OptionalDiagnostic CCEDiag(SourceLocation Loc, diag::kind DiagId 487 = diag::note_invalid_subexpr_in_const_expr, 488 unsigned ExtraNotes = 0) { 489 // Don't override a previous diagnostic. 490 if (!EvalStatus.Diag || !EvalStatus.Diag->empty()) 491 return OptionalDiagnostic(); 492 return Diag(Loc, DiagId, ExtraNotes); 493 } 494 495 /// Add a note to a prior diagnostic. 496 OptionalDiagnostic Note(SourceLocation Loc, diag::kind DiagId) { 497 if (!HasActiveDiagnostic) 498 return OptionalDiagnostic(); 499 return OptionalDiagnostic(&addDiag(Loc, DiagId)); 500 } 501 502 /// Add a stack of notes to a prior diagnostic. 503 void addNotes(ArrayRef<PartialDiagnosticAt> Diags) { 504 if (HasActiveDiagnostic) { 505 EvalStatus.Diag->insert(EvalStatus.Diag->end(), 506 Diags.begin(), Diags.end()); 507 } 508 } 509 510 /// Should we continue evaluation as much as possible after encountering a 511 /// construct which can't be folded? 512 bool keepEvaluatingAfterFailure() { 513 return CheckingPotentialConstantExpression && EvalStatus.Diag->empty(); 514 } 515 }; 516 517 /// Object used to treat all foldable expressions as constant expressions. 518 struct FoldConstant { 519 bool Enabled; 520 521 explicit FoldConstant(EvalInfo &Info) 522 : Enabled(Info.EvalStatus.Diag && Info.EvalStatus.Diag->empty() && 523 !Info.EvalStatus.HasSideEffects) { 524 } 525 // Treat the value we've computed since this object was created as constant. 526 void Fold(EvalInfo &Info) { 527 if (Enabled && !Info.EvalStatus.Diag->empty() && 528 !Info.EvalStatus.HasSideEffects) 529 Info.EvalStatus.Diag->clear(); 530 } 531 }; 532} 533 534bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E, 535 CheckSubobjectKind CSK) { 536 if (Invalid) 537 return false; 538 if (isOnePastTheEnd()) { 539 Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_past_end_subobject) 540 << CSK; 541 setInvalid(); 542 return false; 543 } 544 return true; 545} 546 547void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info, 548 const Expr *E, uint64_t N) { 549 if (MostDerivedPathLength == Entries.size() && MostDerivedArraySize) 550 Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_array_index) 551 << static_cast<int>(N) << /*array*/ 0 552 << static_cast<unsigned>(MostDerivedArraySize); 553 else 554 Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_array_index) 555 << static_cast<int>(N) << /*non-array*/ 1; 556 setInvalid(); 557} 558 559CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc, 560 const FunctionDecl *Callee, const LValue *This, 561 const CCValue *Arguments) 562 : Info(Info), Caller(Info.CurrentCall), CallLoc(CallLoc), Callee(Callee), 563 This(This), Arguments(Arguments) { 564 Info.CurrentCall = this; 565 ++Info.CallStackDepth; 566} 567 568CallStackFrame::~CallStackFrame() { 569 assert(Info.CurrentCall == this && "calls retired out of order"); 570 --Info.CallStackDepth; 571 Info.CurrentCall = Caller; 572} 573 574/// Produce a string describing the given constexpr call. 575static void describeCall(CallStackFrame *Frame, llvm::raw_ostream &Out) { 576 unsigned ArgIndex = 0; 577 bool IsMemberCall = isa<CXXMethodDecl>(Frame->Callee) && 578 !isa<CXXConstructorDecl>(Frame->Callee) && 579 cast<CXXMethodDecl>(Frame->Callee)->isInstance(); 580 581 if (!IsMemberCall) 582 Out << *Frame->Callee << '('; 583 584 for (FunctionDecl::param_const_iterator I = Frame->Callee->param_begin(), 585 E = Frame->Callee->param_end(); I != E; ++I, ++ArgIndex) { 586 if (ArgIndex > (unsigned)IsMemberCall) 587 Out << ", "; 588 589 const ParmVarDecl *Param = *I; 590 const CCValue &Arg = Frame->Arguments[ArgIndex]; 591 if (!Arg.isLValue() || Arg.getLValueDesignator().Invalid) 592 Arg.printPretty(Out, Frame->Info.Ctx, Param->getType()); 593 else { 594 // Deliberately slice off the frame to form an APValue we can print. 595 APValue Value(Arg.getLValueBase(), Arg.getLValueOffset(), 596 Arg.getLValueDesignator().Entries, 597 Arg.getLValueDesignator().IsOnePastTheEnd); 598 Value.printPretty(Out, Frame->Info.Ctx, Param->getType()); 599 } 600 601 if (ArgIndex == 0 && IsMemberCall) 602 Out << "->" << *Frame->Callee << '('; 603 } 604 605 Out << ')'; 606} 607 608void EvalInfo::addCallStack(unsigned Limit) { 609 // Determine which calls to skip, if any. 610 unsigned ActiveCalls = CallStackDepth - 1; 611 unsigned SkipStart = ActiveCalls, SkipEnd = SkipStart; 612 if (Limit && Limit < ActiveCalls) { 613 SkipStart = Limit / 2 + Limit % 2; 614 SkipEnd = ActiveCalls - Limit / 2; 615 } 616 617 // Walk the call stack and add the diagnostics. 618 unsigned CallIdx = 0; 619 for (CallStackFrame *Frame = CurrentCall; Frame != &BottomFrame; 620 Frame = Frame->Caller, ++CallIdx) { 621 // Skip this call? 622 if (CallIdx >= SkipStart && CallIdx < SkipEnd) { 623 if (CallIdx == SkipStart) { 624 // Note that we're skipping calls. 625 addDiag(Frame->CallLoc, diag::note_constexpr_calls_suppressed) 626 << unsigned(ActiveCalls - Limit); 627 } 628 continue; 629 } 630 631 llvm::SmallVector<char, 128> Buffer; 632 llvm::raw_svector_ostream Out(Buffer); 633 describeCall(Frame, Out); 634 addDiag(Frame->CallLoc, diag::note_constexpr_call_here) << Out.str(); 635 } 636} 637 638namespace { 639 struct ComplexValue { 640 private: 641 bool IsInt; 642 643 public: 644 APSInt IntReal, IntImag; 645 APFloat FloatReal, FloatImag; 646 647 ComplexValue() : FloatReal(APFloat::Bogus), FloatImag(APFloat::Bogus) {} 648 649 void makeComplexFloat() { IsInt = false; } 650 bool isComplexFloat() const { return !IsInt; } 651 APFloat &getComplexFloatReal() { return FloatReal; } 652 APFloat &getComplexFloatImag() { return FloatImag; } 653 654 void makeComplexInt() { IsInt = true; } 655 bool isComplexInt() const { return IsInt; } 656 APSInt &getComplexIntReal() { return IntReal; } 657 APSInt &getComplexIntImag() { return IntImag; } 658 659 void moveInto(CCValue &v) const { 660 if (isComplexFloat()) 661 v = CCValue(FloatReal, FloatImag); 662 else 663 v = CCValue(IntReal, IntImag); 664 } 665 void setFrom(const CCValue &v) { 666 assert(v.isComplexFloat() || v.isComplexInt()); 667 if (v.isComplexFloat()) { 668 makeComplexFloat(); 669 FloatReal = v.getComplexFloatReal(); 670 FloatImag = v.getComplexFloatImag(); 671 } else { 672 makeComplexInt(); 673 IntReal = v.getComplexIntReal(); 674 IntImag = v.getComplexIntImag(); 675 } 676 } 677 }; 678 679 struct LValue { 680 APValue::LValueBase Base; 681 CharUnits Offset; 682 CallStackFrame *Frame; 683 SubobjectDesignator Designator; 684 685 const APValue::LValueBase getLValueBase() const { return Base; } 686 CharUnits &getLValueOffset() { return Offset; } 687 const CharUnits &getLValueOffset() const { return Offset; } 688 CallStackFrame *getLValueFrame() const { return Frame; } 689 SubobjectDesignator &getLValueDesignator() { return Designator; } 690 const SubobjectDesignator &getLValueDesignator() const { return Designator;} 691 692 void moveInto(CCValue &V) const { 693 V = CCValue(Base, Offset, Frame, Designator); 694 } 695 void setFrom(const CCValue &V) { 696 assert(V.isLValue()); 697 Base = V.getLValueBase(); 698 Offset = V.getLValueOffset(); 699 Frame = V.getLValueFrame(); 700 Designator = V.getLValueDesignator(); 701 } 702 703 void set(APValue::LValueBase B, CallStackFrame *F = 0) { 704 Base = B; 705 Offset = CharUnits::Zero(); 706 Frame = F; 707 Designator = SubobjectDesignator(getType(B)); 708 } 709 710 // Check that this LValue is not based on a null pointer. If it is, produce 711 // a diagnostic and mark the designator as invalid. 712 bool checkNullPointer(EvalInfo &Info, const Expr *E, 713 CheckSubobjectKind CSK) { 714 if (Designator.Invalid) 715 return false; 716 if (!Base) { 717 Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_null_subobject) 718 << CSK; 719 Designator.setInvalid(); 720 return false; 721 } 722 return true; 723 } 724 725 // Check this LValue refers to an object. If not, set the designator to be 726 // invalid and emit a diagnostic. 727 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) { 728 return checkNullPointer(Info, E, CSK) && 729 Designator.checkSubobject(Info, E, CSK); 730 } 731 732 void addDecl(EvalInfo &Info, const Expr *E, 733 const Decl *D, bool Virtual = false) { 734 checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base); 735 Designator.addDeclUnchecked(D, Virtual); 736 } 737 void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) { 738 checkSubobject(Info, E, CSK_ArrayToPointer); 739 Designator.addArrayUnchecked(CAT); 740 } 741 void adjustIndex(EvalInfo &Info, const Expr *E, uint64_t N) { 742 if (!checkNullPointer(Info, E, CSK_ArrayIndex)) 743 return; 744 Designator.adjustIndex(Info, E, N); 745 } 746 }; 747 748 struct MemberPtr { 749 MemberPtr() {} 750 explicit MemberPtr(const ValueDecl *Decl) : 751 DeclAndIsDerivedMember(Decl, false), Path() {} 752 753 /// The member or (direct or indirect) field referred to by this member 754 /// pointer, or 0 if this is a null member pointer. 755 const ValueDecl *getDecl() const { 756 return DeclAndIsDerivedMember.getPointer(); 757 } 758 /// Is this actually a member of some type derived from the relevant class? 759 bool isDerivedMember() const { 760 return DeclAndIsDerivedMember.getInt(); 761 } 762 /// Get the class which the declaration actually lives in. 763 const CXXRecordDecl *getContainingRecord() const { 764 return cast<CXXRecordDecl>( 765 DeclAndIsDerivedMember.getPointer()->getDeclContext()); 766 } 767 768 void moveInto(CCValue &V) const { 769 V = CCValue(getDecl(), isDerivedMember(), Path); 770 } 771 void setFrom(const CCValue &V) { 772 assert(V.isMemberPointer()); 773 DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl()); 774 DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember()); 775 Path.clear(); 776 ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath(); 777 Path.insert(Path.end(), P.begin(), P.end()); 778 } 779 780 /// DeclAndIsDerivedMember - The member declaration, and a flag indicating 781 /// whether the member is a member of some class derived from the class type 782 /// of the member pointer. 783 llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember; 784 /// Path - The path of base/derived classes from the member declaration's 785 /// class (exclusive) to the class type of the member pointer (inclusive). 786 SmallVector<const CXXRecordDecl*, 4> Path; 787 788 /// Perform a cast towards the class of the Decl (either up or down the 789 /// hierarchy). 790 bool castBack(const CXXRecordDecl *Class) { 791 assert(!Path.empty()); 792 const CXXRecordDecl *Expected; 793 if (Path.size() >= 2) 794 Expected = Path[Path.size() - 2]; 795 else 796 Expected = getContainingRecord(); 797 if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) { 798 // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*), 799 // if B does not contain the original member and is not a base or 800 // derived class of the class containing the original member, the result 801 // of the cast is undefined. 802 // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to 803 // (D::*). We consider that to be a language defect. 804 return false; 805 } 806 Path.pop_back(); 807 return true; 808 } 809 /// Perform a base-to-derived member pointer cast. 810 bool castToDerived(const CXXRecordDecl *Derived) { 811 if (!getDecl()) 812 return true; 813 if (!isDerivedMember()) { 814 Path.push_back(Derived); 815 return true; 816 } 817 if (!castBack(Derived)) 818 return false; 819 if (Path.empty()) 820 DeclAndIsDerivedMember.setInt(false); 821 return true; 822 } 823 /// Perform a derived-to-base member pointer cast. 824 bool castToBase(const CXXRecordDecl *Base) { 825 if (!getDecl()) 826 return true; 827 if (Path.empty()) 828 DeclAndIsDerivedMember.setInt(true); 829 if (isDerivedMember()) { 830 Path.push_back(Base); 831 return true; 832 } 833 return castBack(Base); 834 } 835 }; 836 837 /// Compare two member pointers, which are assumed to be of the same type. 838 static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) { 839 if (!LHS.getDecl() || !RHS.getDecl()) 840 return !LHS.getDecl() && !RHS.getDecl(); 841 if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl()) 842 return false; 843 return LHS.Path == RHS.Path; 844 } 845 846 /// Kinds of constant expression checking, for diagnostics. 847 enum CheckConstantExpressionKind { 848 CCEK_Constant, ///< A normal constant. 849 CCEK_ReturnValue, ///< A constexpr function return value. 850 CCEK_MemberInit ///< A constexpr constructor mem-initializer. 851 }; 852} 853 854static bool Evaluate(CCValue &Result, EvalInfo &Info, const Expr *E); 855static bool EvaluateConstantExpression(APValue &Result, EvalInfo &Info, 856 const LValue &This, const Expr *E, 857 CheckConstantExpressionKind CCEK 858 = CCEK_Constant); 859static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info); 860static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info); 861static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result, 862 EvalInfo &Info); 863static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info); 864static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info); 865static bool EvaluateIntegerOrLValue(const Expr *E, CCValue &Result, 866 EvalInfo &Info); 867static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info); 868static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info); 869 870//===----------------------------------------------------------------------===// 871// Misc utilities 872//===----------------------------------------------------------------------===// 873 874/// Should this call expression be treated as a string literal? 875static bool IsStringLiteralCall(const CallExpr *E) { 876 unsigned Builtin = E->isBuiltinCall(); 877 return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString || 878 Builtin == Builtin::BI__builtin___NSStringMakeConstantString); 879} 880 881static bool IsGlobalLValue(APValue::LValueBase B) { 882 // C++11 [expr.const]p3 An address constant expression is a prvalue core 883 // constant expression of pointer type that evaluates to... 884 885 // ... a null pointer value, or a prvalue core constant expression of type 886 // std::nullptr_t. 887 if (!B) return true; 888 889 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) { 890 // ... the address of an object with static storage duration, 891 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 892 return VD->hasGlobalStorage(); 893 // ... the address of a function, 894 return isa<FunctionDecl>(D); 895 } 896 897 const Expr *E = B.get<const Expr*>(); 898 switch (E->getStmtClass()) { 899 default: 900 return false; 901 case Expr::CompoundLiteralExprClass: 902 return cast<CompoundLiteralExpr>(E)->isFileScope(); 903 // A string literal has static storage duration. 904 case Expr::StringLiteralClass: 905 case Expr::PredefinedExprClass: 906 case Expr::ObjCStringLiteralClass: 907 case Expr::ObjCEncodeExprClass: 908 case Expr::CXXTypeidExprClass: 909 return true; 910 case Expr::CallExprClass: 911 return IsStringLiteralCall(cast<CallExpr>(E)); 912 // For GCC compatibility, &&label has static storage duration. 913 case Expr::AddrLabelExprClass: 914 return true; 915 // A Block literal expression may be used as the initialization value for 916 // Block variables at global or local static scope. 917 case Expr::BlockExprClass: 918 return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures(); 919 case Expr::ImplicitValueInitExprClass: 920 // FIXME: 921 // We can never form an lvalue with an implicit value initialization as its 922 // base through expression evaluation, so these only appear in one case: the 923 // implicit variable declaration we invent when checking whether a constexpr 924 // constructor can produce a constant expression. We must assume that such 925 // an expression might be a global lvalue. 926 return true; 927 } 928} 929 930/// Check that this reference or pointer core constant expression is a valid 931/// value for an address or reference constant expression. Type T should be 932/// either LValue or CCValue. Return true if we can fold this expression, 933/// whether or not it's a constant expression. 934template<typename T> 935static bool CheckLValueConstantExpression(EvalInfo &Info, const Expr *E, 936 const T &LVal, APValue &Value, 937 CheckConstantExpressionKind CCEK) { 938 APValue::LValueBase Base = LVal.getLValueBase(); 939 const SubobjectDesignator &Designator = LVal.getLValueDesignator(); 940 941 if (!IsGlobalLValue(Base)) { 942 if (Info.getLangOpts().CPlusPlus0x) { 943 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>(); 944 Info.Diag(E->getExprLoc(), diag::note_constexpr_non_global, 1) 945 << E->isGLValue() << !Designator.Entries.empty() 946 << !!VD << CCEK << VD; 947 if (VD) 948 Info.Note(VD->getLocation(), diag::note_declared_at); 949 else 950 Info.Note(Base.dyn_cast<const Expr*>()->getExprLoc(), 951 diag::note_constexpr_temporary_here); 952 } else { 953 Info.Diag(E->getExprLoc()); 954 } 955 // Don't allow references to temporaries to escape. 956 return false; 957 } 958 959 bool IsReferenceType = E->isGLValue(); 960 961 if (Designator.Invalid) { 962 // This is not a core constant expression. An appropriate diagnostic will 963 // have already been produced. 964 Value = APValue(LVal.getLValueBase(), LVal.getLValueOffset(), 965 APValue::NoLValuePath()); 966 return true; 967 } 968 969 Value = APValue(LVal.getLValueBase(), LVal.getLValueOffset(), 970 Designator.Entries, Designator.IsOnePastTheEnd); 971 972 // Allow address constant expressions to be past-the-end pointers. This is 973 // an extension: the standard requires them to point to an object. 974 if (!IsReferenceType) 975 return true; 976 977 // A reference constant expression must refer to an object. 978 if (!Base) { 979 // FIXME: diagnostic 980 Info.CCEDiag(E->getExprLoc()); 981 return true; 982 } 983 984 // Does this refer one past the end of some object? 985 if (Designator.isOnePastTheEnd()) { 986 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>(); 987 Info.Diag(E->getExprLoc(), diag::note_constexpr_past_end, 1) 988 << !Designator.Entries.empty() << !!VD << VD; 989 if (VD) 990 Info.Note(VD->getLocation(), diag::note_declared_at); 991 else 992 Info.Note(Base.dyn_cast<const Expr*>()->getExprLoc(), 993 diag::note_constexpr_temporary_here); 994 } 995 996 return true; 997} 998 999/// Check that this core constant expression is of literal type, and if not, 1000/// produce an appropriate diagnostic. 1001static bool CheckLiteralType(EvalInfo &Info, const Expr *E) { 1002 if (!E->isRValue() || E->getType()->isLiteralType()) 1003 return true; 1004 1005 // Prvalue constant expressions must be of literal types. 1006 if (Info.getLangOpts().CPlusPlus0x) 1007 Info.Diag(E->getExprLoc(), diag::note_constexpr_nonliteral) 1008 << E->getType(); 1009 else 1010 Info.Diag(E->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 1011 return false; 1012} 1013 1014/// Check that this core constant expression value is a valid value for a 1015/// constant expression, and if it is, produce the corresponding constant value. 1016/// If not, report an appropriate diagnostic. Does not check that the expression 1017/// is of literal type. 1018static bool CheckConstantExpression(EvalInfo &Info, const Expr *E, 1019 const CCValue &CCValue, APValue &Value, 1020 CheckConstantExpressionKind CCEK 1021 = CCEK_Constant) { 1022 if (!CCValue.isLValue()) { 1023 Value = CCValue; 1024 return true; 1025 } 1026 return CheckLValueConstantExpression(Info, E, CCValue, Value, CCEK); 1027} 1028 1029const ValueDecl *GetLValueBaseDecl(const LValue &LVal) { 1030 return LVal.Base.dyn_cast<const ValueDecl*>(); 1031} 1032 1033static bool IsLiteralLValue(const LValue &Value) { 1034 return Value.Base.dyn_cast<const Expr*>() && !Value.Frame; 1035} 1036 1037static bool IsWeakLValue(const LValue &Value) { 1038 const ValueDecl *Decl = GetLValueBaseDecl(Value); 1039 return Decl && Decl->isWeak(); 1040} 1041 1042static bool EvalPointerValueAsBool(const CCValue &Value, bool &Result) { 1043 // A null base expression indicates a null pointer. These are always 1044 // evaluatable, and they are false unless the offset is zero. 1045 if (!Value.getLValueBase()) { 1046 Result = !Value.getLValueOffset().isZero(); 1047 return true; 1048 } 1049 1050 // We have a non-null base. These are generally known to be true, but if it's 1051 // a weak declaration it can be null at runtime. 1052 Result = true; 1053 const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>(); 1054 return !Decl || !Decl->isWeak(); 1055} 1056 1057static bool HandleConversionToBool(const CCValue &Val, bool &Result) { 1058 switch (Val.getKind()) { 1059 case APValue::Uninitialized: 1060 return false; 1061 case APValue::Int: 1062 Result = Val.getInt().getBoolValue(); 1063 return true; 1064 case APValue::Float: 1065 Result = !Val.getFloat().isZero(); 1066 return true; 1067 case APValue::ComplexInt: 1068 Result = Val.getComplexIntReal().getBoolValue() || 1069 Val.getComplexIntImag().getBoolValue(); 1070 return true; 1071 case APValue::ComplexFloat: 1072 Result = !Val.getComplexFloatReal().isZero() || 1073 !Val.getComplexFloatImag().isZero(); 1074 return true; 1075 case APValue::LValue: 1076 return EvalPointerValueAsBool(Val, Result); 1077 case APValue::MemberPointer: 1078 Result = Val.getMemberPointerDecl(); 1079 return true; 1080 case APValue::Vector: 1081 case APValue::Array: 1082 case APValue::Struct: 1083 case APValue::Union: 1084 case APValue::AddrLabelDiff: 1085 return false; 1086 } 1087 1088 llvm_unreachable("unknown APValue kind"); 1089} 1090 1091static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result, 1092 EvalInfo &Info) { 1093 assert(E->isRValue() && "missing lvalue-to-rvalue conv in bool condition"); 1094 CCValue Val; 1095 if (!Evaluate(Val, Info, E)) 1096 return false; 1097 return HandleConversionToBool(Val, Result); 1098} 1099 1100template<typename T> 1101static bool HandleOverflow(EvalInfo &Info, const Expr *E, 1102 const T &SrcValue, QualType DestType) { 1103 Info.Diag(E->getExprLoc(), diag::note_constexpr_overflow) 1104 << SrcValue << DestType; 1105 return false; 1106} 1107 1108static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E, 1109 QualType SrcType, const APFloat &Value, 1110 QualType DestType, APSInt &Result) { 1111 unsigned DestWidth = Info.Ctx.getIntWidth(DestType); 1112 // Determine whether we are converting to unsigned or signed. 1113 bool DestSigned = DestType->isSignedIntegerOrEnumerationType(); 1114 1115 Result = APSInt(DestWidth, !DestSigned); 1116 bool ignored; 1117 if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored) 1118 & APFloat::opInvalidOp) 1119 return HandleOverflow(Info, E, Value, DestType); 1120 return true; 1121} 1122 1123static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E, 1124 QualType SrcType, QualType DestType, 1125 APFloat &Result) { 1126 APFloat Value = Result; 1127 bool ignored; 1128 if (Result.convert(Info.Ctx.getFloatTypeSemantics(DestType), 1129 APFloat::rmNearestTiesToEven, &ignored) 1130 & APFloat::opOverflow) 1131 return HandleOverflow(Info, E, Value, DestType); 1132 return true; 1133} 1134 1135static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E, 1136 QualType DestType, QualType SrcType, 1137 APSInt &Value) { 1138 unsigned DestWidth = Info.Ctx.getIntWidth(DestType); 1139 APSInt Result = Value; 1140 // Figure out if this is a truncate, extend or noop cast. 1141 // If the input is signed, do a sign extend, noop, or truncate. 1142 Result = Result.extOrTrunc(DestWidth); 1143 Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType()); 1144 return Result; 1145} 1146 1147static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E, 1148 QualType SrcType, const APSInt &Value, 1149 QualType DestType, APFloat &Result) { 1150 Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1); 1151 if (Result.convertFromAPInt(Value, Value.isSigned(), 1152 APFloat::rmNearestTiesToEven) 1153 & APFloat::opOverflow) 1154 return HandleOverflow(Info, E, Value, DestType); 1155 return true; 1156} 1157 1158static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E, 1159 llvm::APInt &Res) { 1160 CCValue SVal; 1161 if (!Evaluate(SVal, Info, E)) 1162 return false; 1163 if (SVal.isInt()) { 1164 Res = SVal.getInt(); 1165 return true; 1166 } 1167 if (SVal.isFloat()) { 1168 Res = SVal.getFloat().bitcastToAPInt(); 1169 return true; 1170 } 1171 if (SVal.isVector()) { 1172 QualType VecTy = E->getType(); 1173 unsigned VecSize = Info.Ctx.getTypeSize(VecTy); 1174 QualType EltTy = VecTy->castAs<VectorType>()->getElementType(); 1175 unsigned EltSize = Info.Ctx.getTypeSize(EltTy); 1176 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian(); 1177 Res = llvm::APInt::getNullValue(VecSize); 1178 for (unsigned i = 0; i < SVal.getVectorLength(); i++) { 1179 APValue &Elt = SVal.getVectorElt(i); 1180 llvm::APInt EltAsInt; 1181 if (Elt.isInt()) { 1182 EltAsInt = Elt.getInt(); 1183 } else if (Elt.isFloat()) { 1184 EltAsInt = Elt.getFloat().bitcastToAPInt(); 1185 } else { 1186 // Don't try to handle vectors of anything other than int or float 1187 // (not sure if it's possible to hit this case). 1188 Info.Diag(E->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 1189 return false; 1190 } 1191 unsigned BaseEltSize = EltAsInt.getBitWidth(); 1192 if (BigEndian) 1193 Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize); 1194 else 1195 Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize); 1196 } 1197 return true; 1198 } 1199 // Give up if the input isn't an int, float, or vector. For example, we 1200 // reject "(v4i16)(intptr_t)&a". 1201 Info.Diag(E->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 1202 return false; 1203} 1204 1205/// Cast an lvalue referring to a base subobject to a derived class, by 1206/// truncating the lvalue's path to the given length. 1207static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result, 1208 const RecordDecl *TruncatedType, 1209 unsigned TruncatedElements) { 1210 SubobjectDesignator &D = Result.Designator; 1211 1212 // Check we actually point to a derived class object. 1213 if (TruncatedElements == D.Entries.size()) 1214 return true; 1215 assert(TruncatedElements >= D.MostDerivedPathLength && 1216 "not casting to a derived class"); 1217 if (!Result.checkSubobject(Info, E, CSK_Derived)) 1218 return false; 1219 1220 // Truncate the path to the subobject, and remove any derived-to-base offsets. 1221 const RecordDecl *RD = TruncatedType; 1222 for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) { 1223 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 1224 const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]); 1225 if (isVirtualBaseClass(D.Entries[I])) 1226 Result.Offset -= Layout.getVBaseClassOffset(Base); 1227 else 1228 Result.Offset -= Layout.getBaseClassOffset(Base); 1229 RD = Base; 1230 } 1231 D.Entries.resize(TruncatedElements); 1232 return true; 1233} 1234 1235static void HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj, 1236 const CXXRecordDecl *Derived, 1237 const CXXRecordDecl *Base, 1238 const ASTRecordLayout *RL = 0) { 1239 if (!RL) RL = &Info.Ctx.getASTRecordLayout(Derived); 1240 Obj.getLValueOffset() += RL->getBaseClassOffset(Base); 1241 Obj.addDecl(Info, E, Base, /*Virtual*/ false); 1242} 1243 1244static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj, 1245 const CXXRecordDecl *DerivedDecl, 1246 const CXXBaseSpecifier *Base) { 1247 const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl(); 1248 1249 if (!Base->isVirtual()) { 1250 HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl); 1251 return true; 1252 } 1253 1254 SubobjectDesignator &D = Obj.Designator; 1255 if (D.Invalid) 1256 return false; 1257 1258 // Extract most-derived object and corresponding type. 1259 DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl(); 1260 if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength)) 1261 return false; 1262 1263 // Find the virtual base class. 1264 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl); 1265 Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl); 1266 Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true); 1267 return true; 1268} 1269 1270/// Update LVal to refer to the given field, which must be a member of the type 1271/// currently described by LVal. 1272static void HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal, 1273 const FieldDecl *FD, 1274 const ASTRecordLayout *RL = 0) { 1275 if (!RL) 1276 RL = &Info.Ctx.getASTRecordLayout(FD->getParent()); 1277 1278 unsigned I = FD->getFieldIndex(); 1279 LVal.Offset += Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I)); 1280 LVal.addDecl(Info, E, FD); 1281} 1282 1283/// Update LVal to refer to the given indirect field. 1284static void HandleLValueIndirectMember(EvalInfo &Info, const Expr *E, 1285 LValue &LVal, 1286 const IndirectFieldDecl *IFD) { 1287 for (IndirectFieldDecl::chain_iterator C = IFD->chain_begin(), 1288 CE = IFD->chain_end(); C != CE; ++C) 1289 HandleLValueMember(Info, E, LVal, cast<FieldDecl>(*C)); 1290} 1291 1292/// Get the size of the given type in char units. 1293static bool HandleSizeof(EvalInfo &Info, QualType Type, CharUnits &Size) { 1294 // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc 1295 // extension. 1296 if (Type->isVoidType() || Type->isFunctionType()) { 1297 Size = CharUnits::One(); 1298 return true; 1299 } 1300 1301 if (!Type->isConstantSizeType()) { 1302 // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2. 1303 // FIXME: Diagnostic. 1304 return false; 1305 } 1306 1307 Size = Info.Ctx.getTypeSizeInChars(Type); 1308 return true; 1309} 1310 1311/// Update a pointer value to model pointer arithmetic. 1312/// \param Info - Information about the ongoing evaluation. 1313/// \param E - The expression being evaluated, for diagnostic purposes. 1314/// \param LVal - The pointer value to be updated. 1315/// \param EltTy - The pointee type represented by LVal. 1316/// \param Adjustment - The adjustment, in objects of type EltTy, to add. 1317static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E, 1318 LValue &LVal, QualType EltTy, 1319 int64_t Adjustment) { 1320 CharUnits SizeOfPointee; 1321 if (!HandleSizeof(Info, EltTy, SizeOfPointee)) 1322 return false; 1323 1324 // Compute the new offset in the appropriate width. 1325 LVal.Offset += Adjustment * SizeOfPointee; 1326 LVal.adjustIndex(Info, E, Adjustment); 1327 return true; 1328} 1329 1330/// Try to evaluate the initializer for a variable declaration. 1331static bool EvaluateVarDeclInit(EvalInfo &Info, const Expr *E, 1332 const VarDecl *VD, 1333 CallStackFrame *Frame, CCValue &Result) { 1334 // If this is a parameter to an active constexpr function call, perform 1335 // argument substitution. 1336 if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) { 1337 // Assume arguments of a potential constant expression are unknown 1338 // constant expressions. 1339 if (Info.CheckingPotentialConstantExpression) 1340 return false; 1341 if (!Frame || !Frame->Arguments) { 1342 Info.Diag(E->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 1343 return false; 1344 } 1345 Result = Frame->Arguments[PVD->getFunctionScopeIndex()]; 1346 return true; 1347 } 1348 1349 // Dig out the initializer, and use the declaration which it's attached to. 1350 const Expr *Init = VD->getAnyInitializer(VD); 1351 if (!Init || Init->isValueDependent()) { 1352 // If we're checking a potential constant expression, the variable could be 1353 // initialized later. 1354 if (!Info.CheckingPotentialConstantExpression) 1355 Info.Diag(E->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 1356 return false; 1357 } 1358 1359 // If we're currently evaluating the initializer of this declaration, use that 1360 // in-flight value. 1361 if (Info.EvaluatingDecl == VD) { 1362 Result = CCValue(Info.Ctx, *Info.EvaluatingDeclValue, 1363 CCValue::GlobalValue()); 1364 return !Result.isUninit(); 1365 } 1366 1367 // Never evaluate the initializer of a weak variable. We can't be sure that 1368 // this is the definition which will be used. 1369 if (VD->isWeak()) { 1370 Info.Diag(E->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 1371 return false; 1372 } 1373 1374 // Check that we can fold the initializer. In C++, we will have already done 1375 // this in the cases where it matters for conformance. 1376 llvm::SmallVector<PartialDiagnosticAt, 8> Notes; 1377 if (!VD->evaluateValue(Notes)) { 1378 Info.Diag(E->getExprLoc(), diag::note_constexpr_var_init_non_constant, 1379 Notes.size() + 1) << VD; 1380 Info.Note(VD->getLocation(), diag::note_declared_at); 1381 Info.addNotes(Notes); 1382 return false; 1383 } else if (!VD->checkInitIsICE()) { 1384 Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_var_init_non_constant, 1385 Notes.size() + 1) << VD; 1386 Info.Note(VD->getLocation(), diag::note_declared_at); 1387 Info.addNotes(Notes); 1388 } 1389 1390 Result = CCValue(Info.Ctx, *VD->getEvaluatedValue(), CCValue::GlobalValue()); 1391 return true; 1392} 1393 1394static bool IsConstNonVolatile(QualType T) { 1395 Qualifiers Quals = T.getQualifiers(); 1396 return Quals.hasConst() && !Quals.hasVolatile(); 1397} 1398 1399/// Get the base index of the given base class within an APValue representing 1400/// the given derived class. 1401static unsigned getBaseIndex(const CXXRecordDecl *Derived, 1402 const CXXRecordDecl *Base) { 1403 Base = Base->getCanonicalDecl(); 1404 unsigned Index = 0; 1405 for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(), 1406 E = Derived->bases_end(); I != E; ++I, ++Index) { 1407 if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base) 1408 return Index; 1409 } 1410 1411 llvm_unreachable("base class missing from derived class's bases list"); 1412} 1413 1414/// Extract the designated sub-object of an rvalue. 1415static bool ExtractSubobject(EvalInfo &Info, const Expr *E, 1416 CCValue &Obj, QualType ObjType, 1417 const SubobjectDesignator &Sub, QualType SubType) { 1418 if (Sub.Invalid) 1419 // A diagnostic will have already been produced. 1420 return false; 1421 if (Sub.isOnePastTheEnd()) { 1422 Info.Diag(E->getExprLoc(), Info.getLangOpts().CPlusPlus0x ? 1423 (unsigned)diag::note_constexpr_read_past_end : 1424 (unsigned)diag::note_invalid_subexpr_in_const_expr); 1425 return false; 1426 } 1427 if (Sub.Entries.empty()) 1428 return true; 1429 if (Info.CheckingPotentialConstantExpression && Obj.isUninit()) 1430 // This object might be initialized later. 1431 return false; 1432 1433 assert(!Obj.isLValue() && "extracting subobject of lvalue"); 1434 const APValue *O = &Obj; 1435 // Walk the designator's path to find the subobject. 1436 for (unsigned I = 0, N = Sub.Entries.size(); I != N; ++I) { 1437 if (ObjType->isArrayType()) { 1438 // Next subobject is an array element. 1439 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType); 1440 assert(CAT && "vla in literal type?"); 1441 uint64_t Index = Sub.Entries[I].ArrayIndex; 1442 if (CAT->getSize().ule(Index)) { 1443 // Note, it should not be possible to form a pointer with a valid 1444 // designator which points more than one past the end of the array. 1445 Info.Diag(E->getExprLoc(), Info.getLangOpts().CPlusPlus0x ? 1446 (unsigned)diag::note_constexpr_read_past_end : 1447 (unsigned)diag::note_invalid_subexpr_in_const_expr); 1448 return false; 1449 } 1450 if (O->getArrayInitializedElts() > Index) 1451 O = &O->getArrayInitializedElt(Index); 1452 else 1453 O = &O->getArrayFiller(); 1454 ObjType = CAT->getElementType(); 1455 } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) { 1456 if (Field->isMutable()) { 1457 Info.Diag(E->getExprLoc(), diag::note_constexpr_ltor_mutable, 1) 1458 << Field; 1459 Info.Note(Field->getLocation(), diag::note_declared_at); 1460 return false; 1461 } 1462 1463 // Next subobject is a class, struct or union field. 1464 RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl(); 1465 if (RD->isUnion()) { 1466 const FieldDecl *UnionField = O->getUnionField(); 1467 if (!UnionField || 1468 UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) { 1469 Info.Diag(E->getExprLoc(), 1470 diag::note_constexpr_read_inactive_union_member) 1471 << Field << !UnionField << UnionField; 1472 return false; 1473 } 1474 O = &O->getUnionValue(); 1475 } else 1476 O = &O->getStructField(Field->getFieldIndex()); 1477 ObjType = Field->getType(); 1478 1479 if (ObjType.isVolatileQualified()) { 1480 if (Info.getLangOpts().CPlusPlus) { 1481 // FIXME: Include a description of the path to the volatile subobject. 1482 Info.Diag(E->getExprLoc(), diag::note_constexpr_ltor_volatile_obj, 1) 1483 << 2 << Field; 1484 Info.Note(Field->getLocation(), diag::note_declared_at); 1485 } else { 1486 Info.Diag(E->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 1487 } 1488 return false; 1489 } 1490 } else { 1491 // Next subobject is a base class. 1492 const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl(); 1493 const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]); 1494 O = &O->getStructBase(getBaseIndex(Derived, Base)); 1495 ObjType = Info.Ctx.getRecordType(Base); 1496 } 1497 1498 if (O->isUninit()) { 1499 if (!Info.CheckingPotentialConstantExpression) 1500 Info.Diag(E->getExprLoc(), diag::note_constexpr_read_uninit); 1501 return false; 1502 } 1503 } 1504 1505 Obj = CCValue(Info.Ctx, *O, CCValue::GlobalValue()); 1506 return true; 1507} 1508 1509/// Find the position where two subobject designators diverge, or equivalently 1510/// the length of the common initial subsequence. 1511static unsigned FindDesignatorMismatch(QualType ObjType, 1512 const SubobjectDesignator &A, 1513 const SubobjectDesignator &B, 1514 bool &WasArrayIndex) { 1515 unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size()); 1516 for (/**/; I != N; ++I) { 1517 if (!ObjType.isNull() && ObjType->isArrayType()) { 1518 // Next subobject is an array element. 1519 if (A.Entries[I].ArrayIndex != B.Entries[I].ArrayIndex) { 1520 WasArrayIndex = true; 1521 return I; 1522 } 1523 ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType(); 1524 } else { 1525 if (A.Entries[I].BaseOrMember != B.Entries[I].BaseOrMember) { 1526 WasArrayIndex = false; 1527 return I; 1528 } 1529 if (const FieldDecl *FD = getAsField(A.Entries[I])) 1530 // Next subobject is a field. 1531 ObjType = FD->getType(); 1532 else 1533 // Next subobject is a base class. 1534 ObjType = QualType(); 1535 } 1536 } 1537 WasArrayIndex = false; 1538 return I; 1539} 1540 1541/// Determine whether the given subobject designators refer to elements of the 1542/// same array object. 1543static bool AreElementsOfSameArray(QualType ObjType, 1544 const SubobjectDesignator &A, 1545 const SubobjectDesignator &B) { 1546 if (A.Entries.size() != B.Entries.size()) 1547 return false; 1548 1549 bool IsArray = A.MostDerivedArraySize != 0; 1550 if (IsArray && A.MostDerivedPathLength != A.Entries.size()) 1551 // A is a subobject of the array element. 1552 return false; 1553 1554 // If A (and B) designates an array element, the last entry will be the array 1555 // index. That doesn't have to match. Otherwise, we're in the 'implicit array 1556 // of length 1' case, and the entire path must match. 1557 bool WasArrayIndex; 1558 unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex); 1559 return CommonLength >= A.Entries.size() - IsArray; 1560} 1561 1562/// HandleLValueToRValueConversion - Perform an lvalue-to-rvalue conversion on 1563/// the given lvalue. This can also be used for 'lvalue-to-lvalue' conversions 1564/// for looking up the glvalue referred to by an entity of reference type. 1565/// 1566/// \param Info - Information about the ongoing evaluation. 1567/// \param Conv - The expression for which we are performing the conversion. 1568/// Used for diagnostics. 1569/// \param Type - The type we expect this conversion to produce, before 1570/// stripping cv-qualifiers in the case of a non-clas type. 1571/// \param LVal - The glvalue on which we are attempting to perform this action. 1572/// \param RVal - The produced value will be placed here. 1573static bool HandleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv, 1574 QualType Type, 1575 const LValue &LVal, CCValue &RVal) { 1576 // In C, an lvalue-to-rvalue conversion is never a constant expression. 1577 if (!Info.getLangOpts().CPlusPlus) 1578 Info.CCEDiag(Conv->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 1579 1580 if (LVal.Designator.Invalid) 1581 // A diagnostic will have already been produced. 1582 return false; 1583 1584 const Expr *Base = LVal.Base.dyn_cast<const Expr*>(); 1585 CallStackFrame *Frame = LVal.Frame; 1586 SourceLocation Loc = Conv->getExprLoc(); 1587 1588 if (!LVal.Base) { 1589 // FIXME: Indirection through a null pointer deserves a specific diagnostic. 1590 Info.Diag(Loc, diag::note_invalid_subexpr_in_const_expr); 1591 return false; 1592 } 1593 1594 // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type 1595 // is not a constant expression (even if the object is non-volatile). We also 1596 // apply this rule to C++98, in order to conform to the expected 'volatile' 1597 // semantics. 1598 if (Type.isVolatileQualified()) { 1599 if (Info.getLangOpts().CPlusPlus) 1600 Info.Diag(Loc, diag::note_constexpr_ltor_volatile_type) << Type; 1601 else 1602 Info.Diag(Loc); 1603 return false; 1604 } 1605 1606 if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl*>()) { 1607 // In C++98, const, non-volatile integers initialized with ICEs are ICEs. 1608 // In C++11, constexpr, non-volatile variables initialized with constant 1609 // expressions are constant expressions too. Inside constexpr functions, 1610 // parameters are constant expressions even if they're non-const. 1611 // In C, such things can also be folded, although they are not ICEs. 1612 const VarDecl *VD = dyn_cast<VarDecl>(D); 1613 if (const VarDecl *VDef = VD->getDefinition()) 1614 VD = VDef; 1615 if (!VD || VD->isInvalidDecl()) { 1616 Info.Diag(Loc); 1617 return false; 1618 } 1619 1620 // DR1313: If the object is volatile-qualified but the glvalue was not, 1621 // behavior is undefined so the result is not a constant expression. 1622 QualType VT = VD->getType(); 1623 if (VT.isVolatileQualified()) { 1624 if (Info.getLangOpts().CPlusPlus) { 1625 Info.Diag(Loc, diag::note_constexpr_ltor_volatile_obj, 1) << 1 << VD; 1626 Info.Note(VD->getLocation(), diag::note_declared_at); 1627 } else { 1628 Info.Diag(Loc); 1629 } 1630 return false; 1631 } 1632 1633 if (!isa<ParmVarDecl>(VD)) { 1634 if (VD->isConstexpr()) { 1635 // OK, we can read this variable. 1636 } else if (VT->isIntegralOrEnumerationType()) { 1637 if (!VT.isConstQualified()) { 1638 if (Info.getLangOpts().CPlusPlus) { 1639 Info.Diag(Loc, diag::note_constexpr_ltor_non_const_int, 1) << VD; 1640 Info.Note(VD->getLocation(), diag::note_declared_at); 1641 } else { 1642 Info.Diag(Loc); 1643 } 1644 return false; 1645 } 1646 } else if (VT->isFloatingType() && VT.isConstQualified()) { 1647 // We support folding of const floating-point types, in order to make 1648 // static const data members of such types (supported as an extension) 1649 // more useful. 1650 if (Info.getLangOpts().CPlusPlus0x) { 1651 Info.CCEDiag(Loc, diag::note_constexpr_ltor_non_constexpr, 1) << VD; 1652 Info.Note(VD->getLocation(), diag::note_declared_at); 1653 } else { 1654 Info.CCEDiag(Loc); 1655 } 1656 } else { 1657 // FIXME: Allow folding of values of any literal type in all languages. 1658 if (Info.getLangOpts().CPlusPlus0x) { 1659 Info.Diag(Loc, diag::note_constexpr_ltor_non_constexpr, 1) << VD; 1660 Info.Note(VD->getLocation(), diag::note_declared_at); 1661 } else { 1662 Info.Diag(Loc); 1663 } 1664 return false; 1665 } 1666 } 1667 1668 if (!EvaluateVarDeclInit(Info, Conv, VD, Frame, RVal)) 1669 return false; 1670 1671 if (isa<ParmVarDecl>(VD) || !VD->getAnyInitializer()->isLValue()) 1672 return ExtractSubobject(Info, Conv, RVal, VT, LVal.Designator, Type); 1673 1674 // The declaration was initialized by an lvalue, with no lvalue-to-rvalue 1675 // conversion. This happens when the declaration and the lvalue should be 1676 // considered synonymous, for instance when initializing an array of char 1677 // from a string literal. Continue as if the initializer lvalue was the 1678 // value we were originally given. 1679 assert(RVal.getLValueOffset().isZero() && 1680 "offset for lvalue init of non-reference"); 1681 Base = RVal.getLValueBase().get<const Expr*>(); 1682 Frame = RVal.getLValueFrame(); 1683 } 1684 1685 // Volatile temporary objects cannot be read in constant expressions. 1686 if (Base->getType().isVolatileQualified()) { 1687 if (Info.getLangOpts().CPlusPlus) { 1688 Info.Diag(Loc, diag::note_constexpr_ltor_volatile_obj, 1) << 0; 1689 Info.Note(Base->getExprLoc(), diag::note_constexpr_temporary_here); 1690 } else { 1691 Info.Diag(Loc); 1692 } 1693 return false; 1694 } 1695 1696 // FIXME: Support PredefinedExpr, ObjCEncodeExpr, MakeStringConstant 1697 if (const StringLiteral *S = dyn_cast<StringLiteral>(Base)) { 1698 const SubobjectDesignator &Designator = LVal.Designator; 1699 if (Designator.Invalid || Designator.Entries.size() != 1) { 1700 Info.Diag(Conv->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 1701 return false; 1702 } 1703 1704 assert(Type->isIntegerType() && "string element not integer type"); 1705 uint64_t Index = Designator.Entries[0].ArrayIndex; 1706 const ConstantArrayType *CAT = 1707 Info.Ctx.getAsConstantArrayType(S->getType()); 1708 if (Index >= CAT->getSize().getZExtValue()) { 1709 // Note, it should not be possible to form a pointer which points more 1710 // than one past the end of the array without producing a prior const expr 1711 // diagnostic. 1712 Info.Diag(Loc, diag::note_constexpr_read_past_end); 1713 return false; 1714 } 1715 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(), 1716 Type->isUnsignedIntegerType()); 1717 if (Index < S->getLength()) 1718 Value = S->getCodeUnit(Index); 1719 RVal = CCValue(Value); 1720 return true; 1721 } 1722 1723 if (Frame) { 1724 // If this is a temporary expression with a nontrivial initializer, grab the 1725 // value from the relevant stack frame. 1726 RVal = Frame->Temporaries[Base]; 1727 } else if (const CompoundLiteralExpr *CLE 1728 = dyn_cast<CompoundLiteralExpr>(Base)) { 1729 // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the 1730 // initializer until now for such expressions. Such an expression can't be 1731 // an ICE in C, so this only matters for fold. 1732 assert(!Info.getLangOpts().CPlusPlus && "lvalue compound literal in c++?"); 1733 if (!Evaluate(RVal, Info, CLE->getInitializer())) 1734 return false; 1735 } else { 1736 Info.Diag(Conv->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 1737 return false; 1738 } 1739 1740 return ExtractSubobject(Info, Conv, RVal, Base->getType(), LVal.Designator, 1741 Type); 1742} 1743 1744/// Build an lvalue for the object argument of a member function call. 1745static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object, 1746 LValue &This) { 1747 if (Object->getType()->isPointerType()) 1748 return EvaluatePointer(Object, This, Info); 1749 1750 if (Object->isGLValue()) 1751 return EvaluateLValue(Object, This, Info); 1752 1753 if (Object->getType()->isLiteralType()) 1754 return EvaluateTemporary(Object, This, Info); 1755 1756 return false; 1757} 1758 1759/// HandleMemberPointerAccess - Evaluate a member access operation and build an 1760/// lvalue referring to the result. 1761/// 1762/// \param Info - Information about the ongoing evaluation. 1763/// \param BO - The member pointer access operation. 1764/// \param LV - Filled in with a reference to the resulting object. 1765/// \param IncludeMember - Specifies whether the member itself is included in 1766/// the resulting LValue subobject designator. This is not possible when 1767/// creating a bound member function. 1768/// \return The field or method declaration to which the member pointer refers, 1769/// or 0 if evaluation fails. 1770static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info, 1771 const BinaryOperator *BO, 1772 LValue &LV, 1773 bool IncludeMember = true) { 1774 assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI); 1775 1776 bool EvalObjOK = EvaluateObjectArgument(Info, BO->getLHS(), LV); 1777 if (!EvalObjOK && !Info.keepEvaluatingAfterFailure()) 1778 return 0; 1779 1780 MemberPtr MemPtr; 1781 if (!EvaluateMemberPointer(BO->getRHS(), MemPtr, Info)) 1782 return 0; 1783 1784 // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to 1785 // member value, the behavior is undefined. 1786 if (!MemPtr.getDecl()) 1787 return 0; 1788 1789 if (!EvalObjOK) 1790 return 0; 1791 1792 if (MemPtr.isDerivedMember()) { 1793 // This is a member of some derived class. Truncate LV appropriately. 1794 // The end of the derived-to-base path for the base object must match the 1795 // derived-to-base path for the member pointer. 1796 if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() > 1797 LV.Designator.Entries.size()) 1798 return 0; 1799 unsigned PathLengthToMember = 1800 LV.Designator.Entries.size() - MemPtr.Path.size(); 1801 for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) { 1802 const CXXRecordDecl *LVDecl = getAsBaseClass( 1803 LV.Designator.Entries[PathLengthToMember + I]); 1804 const CXXRecordDecl *MPDecl = MemPtr.Path[I]; 1805 if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) 1806 return 0; 1807 } 1808 1809 // Truncate the lvalue to the appropriate derived class. 1810 if (!CastToDerivedClass(Info, BO, LV, MemPtr.getContainingRecord(), 1811 PathLengthToMember)) 1812 return 0; 1813 } else if (!MemPtr.Path.empty()) { 1814 // Extend the LValue path with the member pointer's path. 1815 LV.Designator.Entries.reserve(LV.Designator.Entries.size() + 1816 MemPtr.Path.size() + IncludeMember); 1817 1818 // Walk down to the appropriate base class. 1819 QualType LVType = BO->getLHS()->getType(); 1820 if (const PointerType *PT = LVType->getAs<PointerType>()) 1821 LVType = PT->getPointeeType(); 1822 const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl(); 1823 assert(RD && "member pointer access on non-class-type expression"); 1824 // The first class in the path is that of the lvalue. 1825 for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) { 1826 const CXXRecordDecl *Base = MemPtr.Path[N - I - 1]; 1827 HandleLValueDirectBase(Info, BO, LV, RD, Base); 1828 RD = Base; 1829 } 1830 // Finally cast to the class containing the member. 1831 HandleLValueDirectBase(Info, BO, LV, RD, MemPtr.getContainingRecord()); 1832 } 1833 1834 // Add the member. Note that we cannot build bound member functions here. 1835 if (IncludeMember) { 1836 if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) 1837 HandleLValueMember(Info, BO, LV, FD); 1838 else if (const IndirectFieldDecl *IFD = 1839 dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) 1840 HandleLValueIndirectMember(Info, BO, LV, IFD); 1841 else 1842 llvm_unreachable("can't construct reference to bound member function"); 1843 } 1844 1845 return MemPtr.getDecl(); 1846} 1847 1848/// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on 1849/// the provided lvalue, which currently refers to the base object. 1850static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E, 1851 LValue &Result) { 1852 SubobjectDesignator &D = Result.Designator; 1853 if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived)) 1854 return false; 1855 1856 QualType TargetQT = E->getType(); 1857 if (const PointerType *PT = TargetQT->getAs<PointerType>()) 1858 TargetQT = PT->getPointeeType(); 1859 1860 // Check this cast lands within the final derived-to-base subobject path. 1861 if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) { 1862 Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_invalid_downcast) 1863 << D.MostDerivedType << TargetQT; 1864 return false; 1865 } 1866 1867 // Check the type of the final cast. We don't need to check the path, 1868 // since a cast can only be formed if the path is unique. 1869 unsigned NewEntriesSize = D.Entries.size() - E->path_size(); 1870 const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl(); 1871 const CXXRecordDecl *FinalType; 1872 if (NewEntriesSize == D.MostDerivedPathLength) 1873 FinalType = D.MostDerivedType->getAsCXXRecordDecl(); 1874 else 1875 FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]); 1876 if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) { 1877 Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_invalid_downcast) 1878 << D.MostDerivedType << TargetQT; 1879 return false; 1880 } 1881 1882 // Truncate the lvalue to the appropriate derived class. 1883 return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize); 1884} 1885 1886namespace { 1887enum EvalStmtResult { 1888 /// Evaluation failed. 1889 ESR_Failed, 1890 /// Hit a 'return' statement. 1891 ESR_Returned, 1892 /// Evaluation succeeded. 1893 ESR_Succeeded 1894}; 1895} 1896 1897// Evaluate a statement. 1898static EvalStmtResult EvaluateStmt(APValue &Result, EvalInfo &Info, 1899 const Stmt *S) { 1900 switch (S->getStmtClass()) { 1901 default: 1902 return ESR_Failed; 1903 1904 case Stmt::NullStmtClass: 1905 case Stmt::DeclStmtClass: 1906 return ESR_Succeeded; 1907 1908 case Stmt::ReturnStmtClass: { 1909 CCValue CCResult; 1910 const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue(); 1911 if (!Evaluate(CCResult, Info, RetExpr) || 1912 !CheckConstantExpression(Info, RetExpr, CCResult, Result, 1913 CCEK_ReturnValue)) 1914 return ESR_Failed; 1915 return ESR_Returned; 1916 } 1917 1918 case Stmt::CompoundStmtClass: { 1919 const CompoundStmt *CS = cast<CompoundStmt>(S); 1920 for (CompoundStmt::const_body_iterator BI = CS->body_begin(), 1921 BE = CS->body_end(); BI != BE; ++BI) { 1922 EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI); 1923 if (ESR != ESR_Succeeded) 1924 return ESR; 1925 } 1926 return ESR_Succeeded; 1927 } 1928 } 1929} 1930 1931/// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial 1932/// default constructor. If so, we'll fold it whether or not it's marked as 1933/// constexpr. If it is marked as constexpr, we will never implicitly define it, 1934/// so we need special handling. 1935static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc, 1936 const CXXConstructorDecl *CD, 1937 bool IsValueInitialization) { 1938 if (!CD->isTrivial() || !CD->isDefaultConstructor()) 1939 return false; 1940 1941 // Value-initialization does not call a trivial default constructor, so such a 1942 // call is a core constant expression whether or not the constructor is 1943 // constexpr. 1944 if (!CD->isConstexpr() && !IsValueInitialization) { 1945 if (Info.getLangOpts().CPlusPlus0x) { 1946 // FIXME: If DiagDecl is an implicitly-declared special member function, 1947 // we should be much more explicit about why it's not constexpr. 1948 Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1) 1949 << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD; 1950 Info.Note(CD->getLocation(), diag::note_declared_at); 1951 } else { 1952 Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr); 1953 } 1954 } 1955 return true; 1956} 1957 1958/// CheckConstexprFunction - Check that a function can be called in a constant 1959/// expression. 1960static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc, 1961 const FunctionDecl *Declaration, 1962 const FunctionDecl *Definition) { 1963 // Potential constant expressions can contain calls to declared, but not yet 1964 // defined, constexpr functions. 1965 if (Info.CheckingPotentialConstantExpression && !Definition && 1966 Declaration->isConstexpr()) 1967 return false; 1968 1969 // Can we evaluate this function call? 1970 if (Definition && Definition->isConstexpr() && !Definition->isInvalidDecl()) 1971 return true; 1972 1973 if (Info.getLangOpts().CPlusPlus0x) { 1974 const FunctionDecl *DiagDecl = Definition ? Definition : Declaration; 1975 // FIXME: If DiagDecl is an implicitly-declared special member function, we 1976 // should be much more explicit about why it's not constexpr. 1977 Info.Diag(CallLoc, diag::note_constexpr_invalid_function, 1) 1978 << DiagDecl->isConstexpr() << isa<CXXConstructorDecl>(DiagDecl) 1979 << DiagDecl; 1980 Info.Note(DiagDecl->getLocation(), diag::note_declared_at); 1981 } else { 1982 Info.Diag(CallLoc, diag::note_invalid_subexpr_in_const_expr); 1983 } 1984 return false; 1985} 1986 1987namespace { 1988typedef SmallVector<CCValue, 8> ArgVector; 1989} 1990 1991/// EvaluateArgs - Evaluate the arguments to a function call. 1992static bool EvaluateArgs(ArrayRef<const Expr*> Args, ArgVector &ArgValues, 1993 EvalInfo &Info) { 1994 bool Success = true; 1995 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end(); 1996 I != E; ++I) { 1997 if (!Evaluate(ArgValues[I - Args.begin()], Info, *I)) { 1998 // If we're checking for a potential constant expression, evaluate all 1999 // initializers even if some of them fail. 2000 if (!Info.keepEvaluatingAfterFailure()) 2001 return false; 2002 Success = false; 2003 } 2004 } 2005 return Success; 2006} 2007 2008/// Evaluate a function call. 2009static bool HandleFunctionCall(SourceLocation CallLoc, 2010 const FunctionDecl *Callee, const LValue *This, 2011 ArrayRef<const Expr*> Args, const Stmt *Body, 2012 EvalInfo &Info, APValue &Result) { 2013 ArgVector ArgValues(Args.size()); 2014 if (!EvaluateArgs(Args, ArgValues, Info)) 2015 return false; 2016 2017 if (!Info.CheckCallLimit(CallLoc)) 2018 return false; 2019 2020 CallStackFrame Frame(Info, CallLoc, Callee, This, ArgValues.data()); 2021 return EvaluateStmt(Result, Info, Body) == ESR_Returned; 2022} 2023 2024/// Evaluate a constructor call. 2025static bool HandleConstructorCall(SourceLocation CallLoc, const LValue &This, 2026 ArrayRef<const Expr*> Args, 2027 const CXXConstructorDecl *Definition, 2028 EvalInfo &Info, APValue &Result) { 2029 ArgVector ArgValues(Args.size()); 2030 if (!EvaluateArgs(Args, ArgValues, Info)) 2031 return false; 2032 2033 if (!Info.CheckCallLimit(CallLoc)) 2034 return false; 2035 2036 const CXXRecordDecl *RD = Definition->getParent(); 2037 if (RD->getNumVBases()) { 2038 Info.Diag(CallLoc, diag::note_constexpr_virtual_base) << RD; 2039 return false; 2040 } 2041 2042 CallStackFrame Frame(Info, CallLoc, Definition, &This, ArgValues.data()); 2043 2044 // If it's a delegating constructor, just delegate. 2045 if (Definition->isDelegatingConstructor()) { 2046 CXXConstructorDecl::init_const_iterator I = Definition->init_begin(); 2047 return EvaluateConstantExpression(Result, Info, This, (*I)->getInit()); 2048 } 2049 2050 // For a trivial copy or move constructor, perform an APValue copy. This is 2051 // essential for unions, where the operations performed by the constructor 2052 // cannot be represented by ctor-initializers. 2053 if (Definition->isDefaulted() && 2054 ((Definition->isCopyConstructor() && RD->hasTrivialCopyConstructor()) || 2055 (Definition->isMoveConstructor() && RD->hasTrivialMoveConstructor()))) { 2056 LValue RHS; 2057 RHS.setFrom(ArgValues[0]); 2058 CCValue Value; 2059 if (!HandleLValueToRValueConversion(Info, Args[0], Args[0]->getType(), 2060 RHS, Value)) 2061 return false; 2062 assert((Value.isStruct() || Value.isUnion()) && 2063 "trivial copy/move from non-class type?"); 2064 // Any CCValue of class type must already be a constant expression. 2065 Result = Value; 2066 return true; 2067 } 2068 2069 // Reserve space for the struct members. 2070 if (!RD->isUnion() && Result.isUninit()) 2071 Result = APValue(APValue::UninitStruct(), RD->getNumBases(), 2072 std::distance(RD->field_begin(), RD->field_end())); 2073 2074 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 2075 2076 bool Success = true; 2077 unsigned BasesSeen = 0; 2078#ifndef NDEBUG 2079 CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin(); 2080#endif 2081 for (CXXConstructorDecl::init_const_iterator I = Definition->init_begin(), 2082 E = Definition->init_end(); I != E; ++I) { 2083 LValue Subobject = This; 2084 APValue *Value = &Result; 2085 2086 // Determine the subobject to initialize. 2087 if ((*I)->isBaseInitializer()) { 2088 QualType BaseType((*I)->getBaseClass(), 0); 2089#ifndef NDEBUG 2090 // Non-virtual base classes are initialized in the order in the class 2091 // definition. We have already checked for virtual base classes. 2092 assert(!BaseIt->isVirtual() && "virtual base for literal type"); 2093 assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) && 2094 "base class initializers not in expected order"); 2095 ++BaseIt; 2096#endif 2097 HandleLValueDirectBase(Info, (*I)->getInit(), Subobject, RD, 2098 BaseType->getAsCXXRecordDecl(), &Layout); 2099 Value = &Result.getStructBase(BasesSeen++); 2100 } else if (FieldDecl *FD = (*I)->getMember()) { 2101 HandleLValueMember(Info, (*I)->getInit(), Subobject, FD, &Layout); 2102 if (RD->isUnion()) { 2103 Result = APValue(FD); 2104 Value = &Result.getUnionValue(); 2105 } else { 2106 Value = &Result.getStructField(FD->getFieldIndex()); 2107 } 2108 } else if (IndirectFieldDecl *IFD = (*I)->getIndirectMember()) { 2109 // Walk the indirect field decl's chain to find the object to initialize, 2110 // and make sure we've initialized every step along it. 2111 for (IndirectFieldDecl::chain_iterator C = IFD->chain_begin(), 2112 CE = IFD->chain_end(); 2113 C != CE; ++C) { 2114 FieldDecl *FD = cast<FieldDecl>(*C); 2115 CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent()); 2116 // Switch the union field if it differs. This happens if we had 2117 // preceding zero-initialization, and we're now initializing a union 2118 // subobject other than the first. 2119 // FIXME: In this case, the values of the other subobjects are 2120 // specified, since zero-initialization sets all padding bits to zero. 2121 if (Value->isUninit() || 2122 (Value->isUnion() && Value->getUnionField() != FD)) { 2123 if (CD->isUnion()) 2124 *Value = APValue(FD); 2125 else 2126 *Value = APValue(APValue::UninitStruct(), CD->getNumBases(), 2127 std::distance(CD->field_begin(), CD->field_end())); 2128 } 2129 HandleLValueMember(Info, (*I)->getInit(), Subobject, FD); 2130 if (CD->isUnion()) 2131 Value = &Value->getUnionValue(); 2132 else 2133 Value = &Value->getStructField(FD->getFieldIndex()); 2134 } 2135 } else { 2136 llvm_unreachable("unknown base initializer kind"); 2137 } 2138 2139 if (!EvaluateConstantExpression(*Value, Info, Subobject, (*I)->getInit(), 2140 (*I)->isBaseInitializer() 2141 ? CCEK_Constant : CCEK_MemberInit)) { 2142 // If we're checking for a potential constant expression, evaluate all 2143 // initializers even if some of them fail. 2144 if (!Info.keepEvaluatingAfterFailure()) 2145 return false; 2146 Success = false; 2147 } 2148 } 2149 2150 return Success; 2151} 2152 2153namespace { 2154class HasSideEffect 2155 : public ConstStmtVisitor<HasSideEffect, bool> { 2156 const ASTContext &Ctx; 2157public: 2158 2159 HasSideEffect(const ASTContext &C) : Ctx(C) {} 2160 2161 // Unhandled nodes conservatively default to having side effects. 2162 bool VisitStmt(const Stmt *S) { 2163 return true; 2164 } 2165 2166 bool VisitParenExpr(const ParenExpr *E) { return Visit(E->getSubExpr()); } 2167 bool VisitGenericSelectionExpr(const GenericSelectionExpr *E) { 2168 return Visit(E->getResultExpr()); 2169 } 2170 bool VisitDeclRefExpr(const DeclRefExpr *E) { 2171 if (Ctx.getCanonicalType(E->getType()).isVolatileQualified()) 2172 return true; 2173 return false; 2174 } 2175 bool VisitObjCIvarRefExpr(const ObjCIvarRefExpr *E) { 2176 if (Ctx.getCanonicalType(E->getType()).isVolatileQualified()) 2177 return true; 2178 return false; 2179 } 2180 bool VisitBlockDeclRefExpr (const BlockDeclRefExpr *E) { 2181 if (Ctx.getCanonicalType(E->getType()).isVolatileQualified()) 2182 return true; 2183 return false; 2184 } 2185 2186 // We don't want to evaluate BlockExprs multiple times, as they generate 2187 // a ton of code. 2188 bool VisitBlockExpr(const BlockExpr *E) { return true; } 2189 bool VisitPredefinedExpr(const PredefinedExpr *E) { return false; } 2190 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) 2191 { return Visit(E->getInitializer()); } 2192 bool VisitMemberExpr(const MemberExpr *E) { return Visit(E->getBase()); } 2193 bool VisitIntegerLiteral(const IntegerLiteral *E) { return false; } 2194 bool VisitFloatingLiteral(const FloatingLiteral *E) { return false; } 2195 bool VisitStringLiteral(const StringLiteral *E) { return false; } 2196 bool VisitCharacterLiteral(const CharacterLiteral *E) { return false; } 2197 bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E) 2198 { return false; } 2199 bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E) 2200 { return Visit(E->getLHS()) || Visit(E->getRHS()); } 2201 bool VisitChooseExpr(const ChooseExpr *E) 2202 { return Visit(E->getChosenSubExpr(Ctx)); } 2203 bool VisitCastExpr(const CastExpr *E) { return Visit(E->getSubExpr()); } 2204 bool VisitBinAssign(const BinaryOperator *E) { return true; } 2205 bool VisitCompoundAssignOperator(const BinaryOperator *E) { return true; } 2206 bool VisitBinaryOperator(const BinaryOperator *E) 2207 { return Visit(E->getLHS()) || Visit(E->getRHS()); } 2208 bool VisitUnaryPreInc(const UnaryOperator *E) { return true; } 2209 bool VisitUnaryPostInc(const UnaryOperator *E) { return true; } 2210 bool VisitUnaryPreDec(const UnaryOperator *E) { return true; } 2211 bool VisitUnaryPostDec(const UnaryOperator *E) { return true; } 2212 bool VisitUnaryDeref(const UnaryOperator *E) { 2213 if (Ctx.getCanonicalType(E->getType()).isVolatileQualified()) 2214 return true; 2215 return Visit(E->getSubExpr()); 2216 } 2217 bool VisitUnaryOperator(const UnaryOperator *E) { return Visit(E->getSubExpr()); } 2218 2219 // Has side effects if any element does. 2220 bool VisitInitListExpr(const InitListExpr *E) { 2221 for (unsigned i = 0, e = E->getNumInits(); i != e; ++i) 2222 if (Visit(E->getInit(i))) return true; 2223 if (const Expr *filler = E->getArrayFiller()) 2224 return Visit(filler); 2225 return false; 2226 } 2227 2228 bool VisitSizeOfPackExpr(const SizeOfPackExpr *) { return false; } 2229}; 2230 2231class OpaqueValueEvaluation { 2232 EvalInfo &info; 2233 OpaqueValueExpr *opaqueValue; 2234 2235public: 2236 OpaqueValueEvaluation(EvalInfo &info, OpaqueValueExpr *opaqueValue, 2237 Expr *value) 2238 : info(info), opaqueValue(opaqueValue) { 2239 2240 // If evaluation fails, fail immediately. 2241 if (!Evaluate(info.OpaqueValues[opaqueValue], info, value)) { 2242 this->opaqueValue = 0; 2243 return; 2244 } 2245 } 2246 2247 bool hasError() const { return opaqueValue == 0; } 2248 2249 ~OpaqueValueEvaluation() { 2250 // FIXME: This will not work for recursive constexpr functions using opaque 2251 // values. Restore the former value. 2252 if (opaqueValue) info.OpaqueValues.erase(opaqueValue); 2253 } 2254}; 2255 2256} // end anonymous namespace 2257 2258//===----------------------------------------------------------------------===// 2259// Generic Evaluation 2260//===----------------------------------------------------------------------===// 2261namespace { 2262 2263// FIXME: RetTy is always bool. Remove it. 2264template <class Derived, typename RetTy=bool> 2265class ExprEvaluatorBase 2266 : public ConstStmtVisitor<Derived, RetTy> { 2267private: 2268 RetTy DerivedSuccess(const CCValue &V, const Expr *E) { 2269 return static_cast<Derived*>(this)->Success(V, E); 2270 } 2271 RetTy DerivedZeroInitialization(const Expr *E) { 2272 return static_cast<Derived*>(this)->ZeroInitialization(E); 2273 } 2274 2275protected: 2276 EvalInfo &Info; 2277 typedef ConstStmtVisitor<Derived, RetTy> StmtVisitorTy; 2278 typedef ExprEvaluatorBase ExprEvaluatorBaseTy; 2279 2280 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) { 2281 return Info.CCEDiag(E->getExprLoc(), D); 2282 } 2283 2284 /// Report an evaluation error. This should only be called when an error is 2285 /// first discovered. When propagating an error, just return false. 2286 bool Error(const Expr *E, diag::kind D) { 2287 Info.Diag(E->getExprLoc(), D); 2288 return false; 2289 } 2290 bool Error(const Expr *E) { 2291 return Error(E, diag::note_invalid_subexpr_in_const_expr); 2292 } 2293 2294 RetTy ZeroInitialization(const Expr *E) { return Error(E); } 2295 2296public: 2297 ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {} 2298 2299 RetTy VisitStmt(const Stmt *) { 2300 llvm_unreachable("Expression evaluator should not be called on stmts"); 2301 } 2302 RetTy VisitExpr(const Expr *E) { 2303 return Error(E); 2304 } 2305 2306 RetTy VisitParenExpr(const ParenExpr *E) 2307 { return StmtVisitorTy::Visit(E->getSubExpr()); } 2308 RetTy VisitUnaryExtension(const UnaryOperator *E) 2309 { return StmtVisitorTy::Visit(E->getSubExpr()); } 2310 RetTy VisitUnaryPlus(const UnaryOperator *E) 2311 { return StmtVisitorTy::Visit(E->getSubExpr()); } 2312 RetTy VisitChooseExpr(const ChooseExpr *E) 2313 { return StmtVisitorTy::Visit(E->getChosenSubExpr(Info.Ctx)); } 2314 RetTy VisitGenericSelectionExpr(const GenericSelectionExpr *E) 2315 { return StmtVisitorTy::Visit(E->getResultExpr()); } 2316 RetTy VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E) 2317 { return StmtVisitorTy::Visit(E->getReplacement()); } 2318 RetTy VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E) 2319 { return StmtVisitorTy::Visit(E->getExpr()); } 2320 // We cannot create any objects for which cleanups are required, so there is 2321 // nothing to do here; all cleanups must come from unevaluated subexpressions. 2322 RetTy VisitExprWithCleanups(const ExprWithCleanups *E) 2323 { return StmtVisitorTy::Visit(E->getSubExpr()); } 2324 2325 RetTy VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) { 2326 CCEDiag(E, diag::note_constexpr_invalid_cast) << 0; 2327 return static_cast<Derived*>(this)->VisitCastExpr(E); 2328 } 2329 RetTy VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) { 2330 CCEDiag(E, diag::note_constexpr_invalid_cast) << 1; 2331 return static_cast<Derived*>(this)->VisitCastExpr(E); 2332 } 2333 2334 RetTy VisitBinaryOperator(const BinaryOperator *E) { 2335 switch (E->getOpcode()) { 2336 default: 2337 return Error(E); 2338 2339 case BO_Comma: 2340 VisitIgnoredValue(E->getLHS()); 2341 return StmtVisitorTy::Visit(E->getRHS()); 2342 2343 case BO_PtrMemD: 2344 case BO_PtrMemI: { 2345 LValue Obj; 2346 if (!HandleMemberPointerAccess(Info, E, Obj)) 2347 return false; 2348 CCValue Result; 2349 if (!HandleLValueToRValueConversion(Info, E, E->getType(), Obj, Result)) 2350 return false; 2351 return DerivedSuccess(Result, E); 2352 } 2353 } 2354 } 2355 2356 RetTy VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) { 2357 OpaqueValueEvaluation opaque(Info, E->getOpaqueValue(), E->getCommon()); 2358 if (opaque.hasError()) 2359 return false; 2360 2361 bool cond; 2362 if (!EvaluateAsBooleanCondition(E->getCond(), cond, Info)) 2363 return false; 2364 2365 return StmtVisitorTy::Visit(cond ? E->getTrueExpr() : E->getFalseExpr()); 2366 } 2367 2368 RetTy VisitConditionalOperator(const ConditionalOperator *E) { 2369 bool IsBcpCall = false; 2370 // If the condition (ignoring parens) is a __builtin_constant_p call, 2371 // the result is a constant expression if it can be folded without 2372 // side-effects. This is an important GNU extension. See GCC PR38377 2373 // for discussion. 2374 if (const CallExpr *CallCE = 2375 dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts())) 2376 if (CallCE->isBuiltinCall() == Builtin::BI__builtin_constant_p) 2377 IsBcpCall = true; 2378 2379 // Always assume __builtin_constant_p(...) ? ... : ... is a potential 2380 // constant expression; we can't check whether it's potentially foldable. 2381 if (Info.CheckingPotentialConstantExpression && IsBcpCall) 2382 return false; 2383 2384 FoldConstant Fold(Info); 2385 2386 bool BoolResult; 2387 if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) 2388 return false; 2389 2390 Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr(); 2391 if (!StmtVisitorTy::Visit(EvalExpr)) 2392 return false; 2393 2394 if (IsBcpCall) 2395 Fold.Fold(Info); 2396 2397 return true; 2398 } 2399 2400 RetTy VisitOpaqueValueExpr(const OpaqueValueExpr *E) { 2401 const CCValue *Value = Info.getOpaqueValue(E); 2402 if (!Value) { 2403 const Expr *Source = E->getSourceExpr(); 2404 if (!Source) 2405 return Error(E); 2406 if (Source == E) { // sanity checking. 2407 assert(0 && "OpaqueValueExpr recursively refers to itself"); 2408 return Error(E); 2409 } 2410 return StmtVisitorTy::Visit(Source); 2411 } 2412 return DerivedSuccess(*Value, E); 2413 } 2414 2415 RetTy VisitCallExpr(const CallExpr *E) { 2416 const Expr *Callee = E->getCallee()->IgnoreParens(); 2417 QualType CalleeType = Callee->getType(); 2418 2419 const FunctionDecl *FD = 0; 2420 LValue *This = 0, ThisVal; 2421 llvm::ArrayRef<const Expr*> Args(E->getArgs(), E->getNumArgs()); 2422 bool HasQualifier = false; 2423 2424 // Extract function decl and 'this' pointer from the callee. 2425 if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) { 2426 const ValueDecl *Member = 0; 2427 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) { 2428 // Explicit bound member calls, such as x.f() or p->g(); 2429 if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal)) 2430 return false; 2431 Member = ME->getMemberDecl(); 2432 This = &ThisVal; 2433 HasQualifier = ME->hasQualifier(); 2434 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) { 2435 // Indirect bound member calls ('.*' or '->*'). 2436 Member = HandleMemberPointerAccess(Info, BE, ThisVal, false); 2437 if (!Member) return false; 2438 This = &ThisVal; 2439 } else 2440 return Error(Callee); 2441 2442 FD = dyn_cast<FunctionDecl>(Member); 2443 if (!FD) 2444 return Error(Callee); 2445 } else if (CalleeType->isFunctionPointerType()) { 2446 LValue Call; 2447 if (!EvaluatePointer(Callee, Call, Info)) 2448 return false; 2449 2450 if (!Call.getLValueOffset().isZero()) 2451 return Error(Callee); 2452 FD = dyn_cast_or_null<FunctionDecl>( 2453 Call.getLValueBase().dyn_cast<const ValueDecl*>()); 2454 if (!FD) 2455 return Error(Callee); 2456 2457 // Overloaded operator calls to member functions are represented as normal 2458 // calls with '*this' as the first argument. 2459 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD); 2460 if (MD && !MD->isStatic()) { 2461 // FIXME: When selecting an implicit conversion for an overloaded 2462 // operator delete, we sometimes try to evaluate calls to conversion 2463 // operators without a 'this' parameter! 2464 if (Args.empty()) 2465 return Error(E); 2466 2467 if (!EvaluateObjectArgument(Info, Args[0], ThisVal)) 2468 return false; 2469 This = &ThisVal; 2470 Args = Args.slice(1); 2471 } 2472 2473 // Don't call function pointers which have been cast to some other type. 2474 if (!Info.Ctx.hasSameType(CalleeType->getPointeeType(), FD->getType())) 2475 return Error(E); 2476 } else 2477 return Error(E); 2478 2479 if (This && !This->checkSubobject(Info, E, CSK_This)) 2480 return false; 2481 2482 // DR1358 allows virtual constexpr functions in some cases. Don't allow 2483 // calls to such functions in constant expressions. 2484 if (This && !HasQualifier && 2485 isa<CXXMethodDecl>(FD) && cast<CXXMethodDecl>(FD)->isVirtual()) 2486 return Error(E, diag::note_constexpr_virtual_call); 2487 2488 const FunctionDecl *Definition = 0; 2489 Stmt *Body = FD->getBody(Definition); 2490 APValue Result; 2491 2492 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition) || 2493 !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Body, 2494 Info, Result)) 2495 return false; 2496 2497 return DerivedSuccess(CCValue(Info.Ctx, Result, CCValue::GlobalValue()), E); 2498 } 2499 2500 RetTy VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) { 2501 return StmtVisitorTy::Visit(E->getInitializer()); 2502 } 2503 RetTy VisitInitListExpr(const InitListExpr *E) { 2504 if (E->getNumInits() == 0) 2505 return DerivedZeroInitialization(E); 2506 if (E->getNumInits() == 1) 2507 return StmtVisitorTy::Visit(E->getInit(0)); 2508 return Error(E); 2509 } 2510 RetTy VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) { 2511 return DerivedZeroInitialization(E); 2512 } 2513 RetTy VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) { 2514 return DerivedZeroInitialization(E); 2515 } 2516 RetTy VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) { 2517 return DerivedZeroInitialization(E); 2518 } 2519 2520 /// A member expression where the object is a prvalue is itself a prvalue. 2521 RetTy VisitMemberExpr(const MemberExpr *E) { 2522 assert(!E->isArrow() && "missing call to bound member function?"); 2523 2524 CCValue Val; 2525 if (!Evaluate(Val, Info, E->getBase())) 2526 return false; 2527 2528 QualType BaseTy = E->getBase()->getType(); 2529 2530 const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl()); 2531 if (!FD) return Error(E); 2532 assert(!FD->getType()->isReferenceType() && "prvalue reference?"); 2533 assert(BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl() == 2534 FD->getParent()->getCanonicalDecl() && "record / field mismatch"); 2535 2536 SubobjectDesignator Designator(BaseTy); 2537 Designator.addDeclUnchecked(FD); 2538 2539 return ExtractSubobject(Info, E, Val, BaseTy, Designator, E->getType()) && 2540 DerivedSuccess(Val, E); 2541 } 2542 2543 RetTy VisitCastExpr(const CastExpr *E) { 2544 switch (E->getCastKind()) { 2545 default: 2546 break; 2547 2548 case CK_AtomicToNonAtomic: 2549 case CK_NonAtomicToAtomic: 2550 case CK_NoOp: 2551 case CK_UserDefinedConversion: 2552 return StmtVisitorTy::Visit(E->getSubExpr()); 2553 2554 case CK_LValueToRValue: { 2555 LValue LVal; 2556 if (!EvaluateLValue(E->getSubExpr(), LVal, Info)) 2557 return false; 2558 CCValue RVal; 2559 // Note, we use the subexpression's type in order to retain cv-qualifiers. 2560 if (!HandleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(), 2561 LVal, RVal)) 2562 return false; 2563 return DerivedSuccess(RVal, E); 2564 } 2565 } 2566 2567 return Error(E); 2568 } 2569 2570 /// Visit a value which is evaluated, but whose value is ignored. 2571 void VisitIgnoredValue(const Expr *E) { 2572 CCValue Scratch; 2573 if (!Evaluate(Scratch, Info, E)) 2574 Info.EvalStatus.HasSideEffects = true; 2575 } 2576}; 2577 2578} 2579 2580//===----------------------------------------------------------------------===// 2581// Common base class for lvalue and temporary evaluation. 2582//===----------------------------------------------------------------------===// 2583namespace { 2584template<class Derived> 2585class LValueExprEvaluatorBase 2586 : public ExprEvaluatorBase<Derived, bool> { 2587protected: 2588 LValue &Result; 2589 typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy; 2590 typedef ExprEvaluatorBase<Derived, bool> ExprEvaluatorBaseTy; 2591 2592 bool Success(APValue::LValueBase B) { 2593 Result.set(B); 2594 return true; 2595 } 2596 2597public: 2598 LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result) : 2599 ExprEvaluatorBaseTy(Info), Result(Result) {} 2600 2601 bool Success(const CCValue &V, const Expr *E) { 2602 Result.setFrom(V); 2603 return true; 2604 } 2605 2606 bool VisitMemberExpr(const MemberExpr *E) { 2607 // Handle non-static data members. 2608 QualType BaseTy; 2609 if (E->isArrow()) { 2610 if (!EvaluatePointer(E->getBase(), Result, this->Info)) 2611 return false; 2612 BaseTy = E->getBase()->getType()->getAs<PointerType>()->getPointeeType(); 2613 } else if (E->getBase()->isRValue()) { 2614 assert(E->getBase()->getType()->isRecordType()); 2615 if (!EvaluateTemporary(E->getBase(), Result, this->Info)) 2616 return false; 2617 BaseTy = E->getBase()->getType(); 2618 } else { 2619 if (!this->Visit(E->getBase())) 2620 return false; 2621 BaseTy = E->getBase()->getType(); 2622 } 2623 2624 const ValueDecl *MD = E->getMemberDecl(); 2625 if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) { 2626 assert(BaseTy->getAs<RecordType>()->getDecl()->getCanonicalDecl() == 2627 FD->getParent()->getCanonicalDecl() && "record / field mismatch"); 2628 (void)BaseTy; 2629 HandleLValueMember(this->Info, E, Result, FD); 2630 } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) { 2631 HandleLValueIndirectMember(this->Info, E, Result, IFD); 2632 } else 2633 return this->Error(E); 2634 2635 if (MD->getType()->isReferenceType()) { 2636 CCValue RefValue; 2637 if (!HandleLValueToRValueConversion(this->Info, E, MD->getType(), Result, 2638 RefValue)) 2639 return false; 2640 return Success(RefValue, E); 2641 } 2642 return true; 2643 } 2644 2645 bool VisitBinaryOperator(const BinaryOperator *E) { 2646 switch (E->getOpcode()) { 2647 default: 2648 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 2649 2650 case BO_PtrMemD: 2651 case BO_PtrMemI: 2652 return HandleMemberPointerAccess(this->Info, E, Result); 2653 } 2654 } 2655 2656 bool VisitCastExpr(const CastExpr *E) { 2657 switch (E->getCastKind()) { 2658 default: 2659 return ExprEvaluatorBaseTy::VisitCastExpr(E); 2660 2661 case CK_DerivedToBase: 2662 case CK_UncheckedDerivedToBase: { 2663 if (!this->Visit(E->getSubExpr())) 2664 return false; 2665 2666 // Now figure out the necessary offset to add to the base LV to get from 2667 // the derived class to the base class. 2668 QualType Type = E->getSubExpr()->getType(); 2669 2670 for (CastExpr::path_const_iterator PathI = E->path_begin(), 2671 PathE = E->path_end(); PathI != PathE; ++PathI) { 2672 if (!HandleLValueBase(this->Info, E, Result, Type->getAsCXXRecordDecl(), 2673 *PathI)) 2674 return false; 2675 Type = (*PathI)->getType(); 2676 } 2677 2678 return true; 2679 } 2680 } 2681 } 2682}; 2683} 2684 2685//===----------------------------------------------------------------------===// 2686// LValue Evaluation 2687// 2688// This is used for evaluating lvalues (in C and C++), xvalues (in C++11), 2689// function designators (in C), decl references to void objects (in C), and 2690// temporaries (if building with -Wno-address-of-temporary). 2691// 2692// LValue evaluation produces values comprising a base expression of one of the 2693// following types: 2694// - Declarations 2695// * VarDecl 2696// * FunctionDecl 2697// - Literals 2698// * CompoundLiteralExpr in C 2699// * StringLiteral 2700// * CXXTypeidExpr 2701// * PredefinedExpr 2702// * ObjCStringLiteralExpr 2703// * ObjCEncodeExpr 2704// * AddrLabelExpr 2705// * BlockExpr 2706// * CallExpr for a MakeStringConstant builtin 2707// - Locals and temporaries 2708// * Any Expr, with a Frame indicating the function in which the temporary was 2709// evaluated. 2710// plus an offset in bytes. 2711//===----------------------------------------------------------------------===// 2712namespace { 2713class LValueExprEvaluator 2714 : public LValueExprEvaluatorBase<LValueExprEvaluator> { 2715public: 2716 LValueExprEvaluator(EvalInfo &Info, LValue &Result) : 2717 LValueExprEvaluatorBaseTy(Info, Result) {} 2718 2719 bool VisitVarDecl(const Expr *E, const VarDecl *VD); 2720 2721 bool VisitDeclRefExpr(const DeclRefExpr *E); 2722 bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); } 2723 bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E); 2724 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E); 2725 bool VisitMemberExpr(const MemberExpr *E); 2726 bool VisitStringLiteral(const StringLiteral *E) { return Success(E); } 2727 bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); } 2728 bool VisitCXXTypeidExpr(const CXXTypeidExpr *E); 2729 bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E); 2730 bool VisitUnaryDeref(const UnaryOperator *E); 2731 2732 bool VisitCastExpr(const CastExpr *E) { 2733 switch (E->getCastKind()) { 2734 default: 2735 return LValueExprEvaluatorBaseTy::VisitCastExpr(E); 2736 2737 case CK_LValueBitCast: 2738 this->CCEDiag(E, diag::note_constexpr_invalid_cast) << 2; 2739 if (!Visit(E->getSubExpr())) 2740 return false; 2741 Result.Designator.setInvalid(); 2742 return true; 2743 2744 case CK_BaseToDerived: 2745 if (!Visit(E->getSubExpr())) 2746 return false; 2747 return HandleBaseToDerivedCast(Info, E, Result); 2748 } 2749 } 2750 2751 // FIXME: Missing: __real__, __imag__ 2752 2753}; 2754} // end anonymous namespace 2755 2756/// Evaluate an expression as an lvalue. This can be legitimately called on 2757/// expressions which are not glvalues, in a few cases: 2758/// * function designators in C, 2759/// * "extern void" objects, 2760/// * temporaries, if building with -Wno-address-of-temporary. 2761static bool EvaluateLValue(const Expr* E, LValue& Result, EvalInfo &Info) { 2762 assert((E->isGLValue() || E->getType()->isFunctionType() || 2763 E->getType()->isVoidType() || isa<CXXTemporaryObjectExpr>(E)) && 2764 "can't evaluate expression as an lvalue"); 2765 return LValueExprEvaluator(Info, Result).Visit(E); 2766} 2767 2768bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) { 2769 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl())) 2770 return Success(FD); 2771 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl())) 2772 return VisitVarDecl(E, VD); 2773 return Error(E); 2774} 2775 2776bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) { 2777 if (!VD->getType()->isReferenceType()) { 2778 if (isa<ParmVarDecl>(VD)) { 2779 Result.set(VD, Info.CurrentCall); 2780 return true; 2781 } 2782 return Success(VD); 2783 } 2784 2785 CCValue V; 2786 if (!EvaluateVarDeclInit(Info, E, VD, Info.CurrentCall, V)) 2787 return false; 2788 return Success(V, E); 2789} 2790 2791bool LValueExprEvaluator::VisitMaterializeTemporaryExpr( 2792 const MaterializeTemporaryExpr *E) { 2793 if (E->GetTemporaryExpr()->isRValue()) { 2794 if (E->getType()->isRecordType()) 2795 return EvaluateTemporary(E->GetTemporaryExpr(), Result, Info); 2796 2797 Result.set(E, Info.CurrentCall); 2798 return EvaluateConstantExpression(Info.CurrentCall->Temporaries[E], Info, 2799 Result, E->GetTemporaryExpr()); 2800 } 2801 2802 // Materialization of an lvalue temporary occurs when we need to force a copy 2803 // (for instance, if it's a bitfield). 2804 // FIXME: The AST should contain an lvalue-to-rvalue node for such cases. 2805 if (!Visit(E->GetTemporaryExpr())) 2806 return false; 2807 if (!HandleLValueToRValueConversion(Info, E, E->getType(), Result, 2808 Info.CurrentCall->Temporaries[E])) 2809 return false; 2810 Result.set(E, Info.CurrentCall); 2811 return true; 2812} 2813 2814bool 2815LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) { 2816 assert(!Info.getLangOpts().CPlusPlus && "lvalue compound literal in c++?"); 2817 // Defer visiting the literal until the lvalue-to-rvalue conversion. We can 2818 // only see this when folding in C, so there's no standard to follow here. 2819 return Success(E); 2820} 2821 2822bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) { 2823 if (E->isTypeOperand()) 2824 return Success(E); 2825 CXXRecordDecl *RD = E->getExprOperand()->getType()->getAsCXXRecordDecl(); 2826 if (RD && RD->isPolymorphic()) { 2827 Info.Diag(E->getExprLoc(), diag::note_constexpr_typeid_polymorphic) 2828 << E->getExprOperand()->getType() 2829 << E->getExprOperand()->getSourceRange(); 2830 return false; 2831 } 2832 return Success(E); 2833} 2834 2835bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) { 2836 // Handle static data members. 2837 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) { 2838 VisitIgnoredValue(E->getBase()); 2839 return VisitVarDecl(E, VD); 2840 } 2841 2842 // Handle static member functions. 2843 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) { 2844 if (MD->isStatic()) { 2845 VisitIgnoredValue(E->getBase()); 2846 return Success(MD); 2847 } 2848 } 2849 2850 // Handle non-static data members. 2851 return LValueExprEvaluatorBaseTy::VisitMemberExpr(E); 2852} 2853 2854bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) { 2855 // FIXME: Deal with vectors as array subscript bases. 2856 if (E->getBase()->getType()->isVectorType()) 2857 return Error(E); 2858 2859 if (!EvaluatePointer(E->getBase(), Result, Info)) 2860 return false; 2861 2862 APSInt Index; 2863 if (!EvaluateInteger(E->getIdx(), Index, Info)) 2864 return false; 2865 int64_t IndexValue 2866 = Index.isSigned() ? Index.getSExtValue() 2867 : static_cast<int64_t>(Index.getZExtValue()); 2868 2869 return HandleLValueArrayAdjustment(Info, E, Result, E->getType(), IndexValue); 2870} 2871 2872bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) { 2873 return EvaluatePointer(E->getSubExpr(), Result, Info); 2874} 2875 2876//===----------------------------------------------------------------------===// 2877// Pointer Evaluation 2878//===----------------------------------------------------------------------===// 2879 2880namespace { 2881class PointerExprEvaluator 2882 : public ExprEvaluatorBase<PointerExprEvaluator, bool> { 2883 LValue &Result; 2884 2885 bool Success(const Expr *E) { 2886 Result.set(E); 2887 return true; 2888 } 2889public: 2890 2891 PointerExprEvaluator(EvalInfo &info, LValue &Result) 2892 : ExprEvaluatorBaseTy(info), Result(Result) {} 2893 2894 bool Success(const CCValue &V, const Expr *E) { 2895 Result.setFrom(V); 2896 return true; 2897 } 2898 bool ZeroInitialization(const Expr *E) { 2899 return Success((Expr*)0); 2900 } 2901 2902 bool VisitBinaryOperator(const BinaryOperator *E); 2903 bool VisitCastExpr(const CastExpr* E); 2904 bool VisitUnaryAddrOf(const UnaryOperator *E); 2905 bool VisitObjCStringLiteral(const ObjCStringLiteral *E) 2906 { return Success(E); } 2907 bool VisitAddrLabelExpr(const AddrLabelExpr *E) 2908 { return Success(E); } 2909 bool VisitCallExpr(const CallExpr *E); 2910 bool VisitBlockExpr(const BlockExpr *E) { 2911 if (!E->getBlockDecl()->hasCaptures()) 2912 return Success(E); 2913 return Error(E); 2914 } 2915 bool VisitCXXThisExpr(const CXXThisExpr *E) { 2916 if (!Info.CurrentCall->This) 2917 return Error(E); 2918 Result = *Info.CurrentCall->This; 2919 return true; 2920 } 2921 2922 // FIXME: Missing: @protocol, @selector 2923}; 2924} // end anonymous namespace 2925 2926static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info) { 2927 assert(E->isRValue() && E->getType()->hasPointerRepresentation()); 2928 return PointerExprEvaluator(Info, Result).Visit(E); 2929} 2930 2931bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 2932 if (E->getOpcode() != BO_Add && 2933 E->getOpcode() != BO_Sub) 2934 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 2935 2936 const Expr *PExp = E->getLHS(); 2937 const Expr *IExp = E->getRHS(); 2938 if (IExp->getType()->isPointerType()) 2939 std::swap(PExp, IExp); 2940 2941 bool EvalPtrOK = EvaluatePointer(PExp, Result, Info); 2942 if (!EvalPtrOK && !Info.keepEvaluatingAfterFailure()) 2943 return false; 2944 2945 llvm::APSInt Offset; 2946 if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK) 2947 return false; 2948 int64_t AdditionalOffset 2949 = Offset.isSigned() ? Offset.getSExtValue() 2950 : static_cast<int64_t>(Offset.getZExtValue()); 2951 if (E->getOpcode() == BO_Sub) 2952 AdditionalOffset = -AdditionalOffset; 2953 2954 QualType Pointee = PExp->getType()->getAs<PointerType>()->getPointeeType(); 2955 return HandleLValueArrayAdjustment(Info, E, Result, Pointee, 2956 AdditionalOffset); 2957} 2958 2959bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) { 2960 return EvaluateLValue(E->getSubExpr(), Result, Info); 2961} 2962 2963bool PointerExprEvaluator::VisitCastExpr(const CastExpr* E) { 2964 const Expr* SubExpr = E->getSubExpr(); 2965 2966 switch (E->getCastKind()) { 2967 default: 2968 break; 2969 2970 case CK_BitCast: 2971 case CK_CPointerToObjCPointerCast: 2972 case CK_BlockPointerToObjCPointerCast: 2973 case CK_AnyPointerToBlockPointerCast: 2974 if (!Visit(SubExpr)) 2975 return false; 2976 // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are 2977 // permitted in constant expressions in C++11. Bitcasts from cv void* are 2978 // also static_casts, but we disallow them as a resolution to DR1312. 2979 if (!E->getType()->isVoidPointerType()) { 2980 Result.Designator.setInvalid(); 2981 if (SubExpr->getType()->isVoidPointerType()) 2982 CCEDiag(E, diag::note_constexpr_invalid_cast) 2983 << 3 << SubExpr->getType(); 2984 else 2985 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2; 2986 } 2987 return true; 2988 2989 case CK_DerivedToBase: 2990 case CK_UncheckedDerivedToBase: { 2991 if (!EvaluatePointer(E->getSubExpr(), Result, Info)) 2992 return false; 2993 if (!Result.Base && Result.Offset.isZero()) 2994 return true; 2995 2996 // Now figure out the necessary offset to add to the base LV to get from 2997 // the derived class to the base class. 2998 QualType Type = 2999 E->getSubExpr()->getType()->castAs<PointerType>()->getPointeeType(); 3000 3001 for (CastExpr::path_const_iterator PathI = E->path_begin(), 3002 PathE = E->path_end(); PathI != PathE; ++PathI) { 3003 if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(), 3004 *PathI)) 3005 return false; 3006 Type = (*PathI)->getType(); 3007 } 3008 3009 return true; 3010 } 3011 3012 case CK_BaseToDerived: 3013 if (!Visit(E->getSubExpr())) 3014 return false; 3015 if (!Result.Base && Result.Offset.isZero()) 3016 return true; 3017 return HandleBaseToDerivedCast(Info, E, Result); 3018 3019 case CK_NullToPointer: 3020 return ZeroInitialization(E); 3021 3022 case CK_IntegralToPointer: { 3023 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2; 3024 3025 CCValue Value; 3026 if (!EvaluateIntegerOrLValue(SubExpr, Value, Info)) 3027 break; 3028 3029 if (Value.isInt()) { 3030 unsigned Size = Info.Ctx.getTypeSize(E->getType()); 3031 uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue(); 3032 Result.Base = (Expr*)0; 3033 Result.Offset = CharUnits::fromQuantity(N); 3034 Result.Frame = 0; 3035 Result.Designator.setInvalid(); 3036 return true; 3037 } else { 3038 // Cast is of an lvalue, no need to change value. 3039 Result.setFrom(Value); 3040 return true; 3041 } 3042 } 3043 case CK_ArrayToPointerDecay: 3044 if (SubExpr->isGLValue()) { 3045 if (!EvaluateLValue(SubExpr, Result, Info)) 3046 return false; 3047 } else { 3048 Result.set(SubExpr, Info.CurrentCall); 3049 if (!EvaluateConstantExpression(Info.CurrentCall->Temporaries[SubExpr], 3050 Info, Result, SubExpr)) 3051 return false; 3052 } 3053 // The result is a pointer to the first element of the array. 3054 if (const ConstantArrayType *CAT 3055 = Info.Ctx.getAsConstantArrayType(SubExpr->getType())) 3056 Result.addArray(Info, E, CAT); 3057 else 3058 Result.Designator.setInvalid(); 3059 return true; 3060 3061 case CK_FunctionToPointerDecay: 3062 return EvaluateLValue(SubExpr, Result, Info); 3063 } 3064 3065 return ExprEvaluatorBaseTy::VisitCastExpr(E); 3066} 3067 3068bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) { 3069 if (IsStringLiteralCall(E)) 3070 return Success(E); 3071 3072 return ExprEvaluatorBaseTy::VisitCallExpr(E); 3073} 3074 3075//===----------------------------------------------------------------------===// 3076// Member Pointer Evaluation 3077//===----------------------------------------------------------------------===// 3078 3079namespace { 3080class MemberPointerExprEvaluator 3081 : public ExprEvaluatorBase<MemberPointerExprEvaluator, bool> { 3082 MemberPtr &Result; 3083 3084 bool Success(const ValueDecl *D) { 3085 Result = MemberPtr(D); 3086 return true; 3087 } 3088public: 3089 3090 MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result) 3091 : ExprEvaluatorBaseTy(Info), Result(Result) {} 3092 3093 bool Success(const CCValue &V, const Expr *E) { 3094 Result.setFrom(V); 3095 return true; 3096 } 3097 bool ZeroInitialization(const Expr *E) { 3098 return Success((const ValueDecl*)0); 3099 } 3100 3101 bool VisitCastExpr(const CastExpr *E); 3102 bool VisitUnaryAddrOf(const UnaryOperator *E); 3103}; 3104} // end anonymous namespace 3105 3106static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result, 3107 EvalInfo &Info) { 3108 assert(E->isRValue() && E->getType()->isMemberPointerType()); 3109 return MemberPointerExprEvaluator(Info, Result).Visit(E); 3110} 3111 3112bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) { 3113 switch (E->getCastKind()) { 3114 default: 3115 return ExprEvaluatorBaseTy::VisitCastExpr(E); 3116 3117 case CK_NullToMemberPointer: 3118 return ZeroInitialization(E); 3119 3120 case CK_BaseToDerivedMemberPointer: { 3121 if (!Visit(E->getSubExpr())) 3122 return false; 3123 if (E->path_empty()) 3124 return true; 3125 // Base-to-derived member pointer casts store the path in derived-to-base 3126 // order, so iterate backwards. The CXXBaseSpecifier also provides us with 3127 // the wrong end of the derived->base arc, so stagger the path by one class. 3128 typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter; 3129 for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin()); 3130 PathI != PathE; ++PathI) { 3131 assert(!(*PathI)->isVirtual() && "memptr cast through vbase"); 3132 const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl(); 3133 if (!Result.castToDerived(Derived)) 3134 return Error(E); 3135 } 3136 const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass(); 3137 if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl())) 3138 return Error(E); 3139 return true; 3140 } 3141 3142 case CK_DerivedToBaseMemberPointer: 3143 if (!Visit(E->getSubExpr())) 3144 return false; 3145 for (CastExpr::path_const_iterator PathI = E->path_begin(), 3146 PathE = E->path_end(); PathI != PathE; ++PathI) { 3147 assert(!(*PathI)->isVirtual() && "memptr cast through vbase"); 3148 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl(); 3149 if (!Result.castToBase(Base)) 3150 return Error(E); 3151 } 3152 return true; 3153 } 3154} 3155 3156bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) { 3157 // C++11 [expr.unary.op]p3 has very strict rules on how the address of a 3158 // member can be formed. 3159 return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl()); 3160} 3161 3162//===----------------------------------------------------------------------===// 3163// Record Evaluation 3164//===----------------------------------------------------------------------===// 3165 3166namespace { 3167 class RecordExprEvaluator 3168 : public ExprEvaluatorBase<RecordExprEvaluator, bool> { 3169 const LValue &This; 3170 APValue &Result; 3171 public: 3172 3173 RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result) 3174 : ExprEvaluatorBaseTy(info), This(This), Result(Result) {} 3175 3176 bool Success(const CCValue &V, const Expr *E) { 3177 return CheckConstantExpression(Info, E, V, Result); 3178 } 3179 bool ZeroInitialization(const Expr *E); 3180 3181 bool VisitCastExpr(const CastExpr *E); 3182 bool VisitInitListExpr(const InitListExpr *E); 3183 bool VisitCXXConstructExpr(const CXXConstructExpr *E); 3184 }; 3185} 3186 3187/// Perform zero-initialization on an object of non-union class type. 3188/// C++11 [dcl.init]p5: 3189/// To zero-initialize an object or reference of type T means: 3190/// [...] 3191/// -- if T is a (possibly cv-qualified) non-union class type, 3192/// each non-static data member and each base-class subobject is 3193/// zero-initialized 3194static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E, 3195 const RecordDecl *RD, 3196 const LValue &This, APValue &Result) { 3197 assert(!RD->isUnion() && "Expected non-union class type"); 3198 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD); 3199 Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0, 3200 std::distance(RD->field_begin(), RD->field_end())); 3201 3202 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 3203 3204 if (CD) { 3205 unsigned Index = 0; 3206 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(), 3207 End = CD->bases_end(); I != End; ++I, ++Index) { 3208 const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl(); 3209 LValue Subobject = This; 3210 HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout); 3211 if (!HandleClassZeroInitialization(Info, E, Base, Subobject, 3212 Result.getStructBase(Index))) 3213 return false; 3214 } 3215 } 3216 3217 for (RecordDecl::field_iterator I = RD->field_begin(), End = RD->field_end(); 3218 I != End; ++I) { 3219 // -- if T is a reference type, no initialization is performed. 3220 if ((*I)->getType()->isReferenceType()) 3221 continue; 3222 3223 LValue Subobject = This; 3224 HandleLValueMember(Info, E, Subobject, *I, &Layout); 3225 3226 ImplicitValueInitExpr VIE((*I)->getType()); 3227 if (!EvaluateConstantExpression( 3228 Result.getStructField((*I)->getFieldIndex()), Info, Subobject, &VIE)) 3229 return false; 3230 } 3231 3232 return true; 3233} 3234 3235bool RecordExprEvaluator::ZeroInitialization(const Expr *E) { 3236 const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl(); 3237 if (RD->isUnion()) { 3238 // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the 3239 // object's first non-static named data member is zero-initialized 3240 RecordDecl::field_iterator I = RD->field_begin(); 3241 if (I == RD->field_end()) { 3242 Result = APValue((const FieldDecl*)0); 3243 return true; 3244 } 3245 3246 LValue Subobject = This; 3247 HandleLValueMember(Info, E, Subobject, *I); 3248 Result = APValue(*I); 3249 ImplicitValueInitExpr VIE((*I)->getType()); 3250 return EvaluateConstantExpression(Result.getUnionValue(), Info, 3251 Subobject, &VIE); 3252 } 3253 3254 return HandleClassZeroInitialization(Info, E, RD, This, Result); 3255} 3256 3257bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) { 3258 switch (E->getCastKind()) { 3259 default: 3260 return ExprEvaluatorBaseTy::VisitCastExpr(E); 3261 3262 case CK_ConstructorConversion: 3263 return Visit(E->getSubExpr()); 3264 3265 case CK_DerivedToBase: 3266 case CK_UncheckedDerivedToBase: { 3267 CCValue DerivedObject; 3268 if (!Evaluate(DerivedObject, Info, E->getSubExpr())) 3269 return false; 3270 if (!DerivedObject.isStruct()) 3271 return Error(E->getSubExpr()); 3272 3273 // Derived-to-base rvalue conversion: just slice off the derived part. 3274 APValue *Value = &DerivedObject; 3275 const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl(); 3276 for (CastExpr::path_const_iterator PathI = E->path_begin(), 3277 PathE = E->path_end(); PathI != PathE; ++PathI) { 3278 assert(!(*PathI)->isVirtual() && "record rvalue with virtual base"); 3279 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl(); 3280 Value = &Value->getStructBase(getBaseIndex(RD, Base)); 3281 RD = Base; 3282 } 3283 Result = *Value; 3284 return true; 3285 } 3286 } 3287} 3288 3289bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) { 3290 const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl(); 3291 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 3292 3293 if (RD->isUnion()) { 3294 const FieldDecl *Field = E->getInitializedFieldInUnion(); 3295 Result = APValue(Field); 3296 if (!Field) 3297 return true; 3298 3299 // If the initializer list for a union does not contain any elements, the 3300 // first element of the union is value-initialized. 3301 ImplicitValueInitExpr VIE(Field->getType()); 3302 const Expr *InitExpr = E->getNumInits() ? E->getInit(0) : &VIE; 3303 3304 LValue Subobject = This; 3305 HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout); 3306 return EvaluateConstantExpression(Result.getUnionValue(), Info, 3307 Subobject, InitExpr); 3308 } 3309 3310 assert((!isa<CXXRecordDecl>(RD) || !cast<CXXRecordDecl>(RD)->getNumBases()) && 3311 "initializer list for class with base classes"); 3312 Result = APValue(APValue::UninitStruct(), 0, 3313 std::distance(RD->field_begin(), RD->field_end())); 3314 unsigned ElementNo = 0; 3315 bool Success = true; 3316 for (RecordDecl::field_iterator Field = RD->field_begin(), 3317 FieldEnd = RD->field_end(); Field != FieldEnd; ++Field) { 3318 // Anonymous bit-fields are not considered members of the class for 3319 // purposes of aggregate initialization. 3320 if (Field->isUnnamedBitfield()) 3321 continue; 3322 3323 LValue Subobject = This; 3324 3325 bool HaveInit = ElementNo < E->getNumInits(); 3326 3327 // FIXME: Diagnostics here should point to the end of the initializer 3328 // list, not the start. 3329 HandleLValueMember(Info, HaveInit ? E->getInit(ElementNo) : E, Subobject, 3330 *Field, &Layout); 3331 3332 // Perform an implicit value-initialization for members beyond the end of 3333 // the initializer list. 3334 ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType()); 3335 3336 if (!EvaluateConstantExpression( 3337 Result.getStructField((*Field)->getFieldIndex()), 3338 Info, Subobject, HaveInit ? E->getInit(ElementNo++) : &VIE)) { 3339 if (!Info.keepEvaluatingAfterFailure()) 3340 return false; 3341 Success = false; 3342 } 3343 } 3344 3345 return Success; 3346} 3347 3348bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) { 3349 const CXXConstructorDecl *FD = E->getConstructor(); 3350 bool ZeroInit = E->requiresZeroInitialization(); 3351 if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) { 3352 // If we've already performed zero-initialization, we're already done. 3353 if (!Result.isUninit()) 3354 return true; 3355 3356 if (ZeroInit) 3357 return ZeroInitialization(E); 3358 3359 const CXXRecordDecl *RD = FD->getParent(); 3360 if (RD->isUnion()) 3361 Result = APValue((FieldDecl*)0); 3362 else 3363 Result = APValue(APValue::UninitStruct(), RD->getNumBases(), 3364 std::distance(RD->field_begin(), RD->field_end())); 3365 return true; 3366 } 3367 3368 const FunctionDecl *Definition = 0; 3369 FD->getBody(Definition); 3370 3371 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition)) 3372 return false; 3373 3374 // Avoid materializing a temporary for an elidable copy/move constructor. 3375 if (E->isElidable() && !ZeroInit) 3376 if (const MaterializeTemporaryExpr *ME 3377 = dyn_cast<MaterializeTemporaryExpr>(E->getArg(0))) 3378 return Visit(ME->GetTemporaryExpr()); 3379 3380 if (ZeroInit && !ZeroInitialization(E)) 3381 return false; 3382 3383 llvm::ArrayRef<const Expr*> Args(E->getArgs(), E->getNumArgs()); 3384 return HandleConstructorCall(E->getExprLoc(), This, Args, 3385 cast<CXXConstructorDecl>(Definition), Info, 3386 Result); 3387} 3388 3389static bool EvaluateRecord(const Expr *E, const LValue &This, 3390 APValue &Result, EvalInfo &Info) { 3391 assert(E->isRValue() && E->getType()->isRecordType() && 3392 "can't evaluate expression as a record rvalue"); 3393 return RecordExprEvaluator(Info, This, Result).Visit(E); 3394} 3395 3396//===----------------------------------------------------------------------===// 3397// Temporary Evaluation 3398// 3399// Temporaries are represented in the AST as rvalues, but generally behave like 3400// lvalues. The full-object of which the temporary is a subobject is implicitly 3401// materialized so that a reference can bind to it. 3402//===----------------------------------------------------------------------===// 3403namespace { 3404class TemporaryExprEvaluator 3405 : public LValueExprEvaluatorBase<TemporaryExprEvaluator> { 3406public: 3407 TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) : 3408 LValueExprEvaluatorBaseTy(Info, Result) {} 3409 3410 /// Visit an expression which constructs the value of this temporary. 3411 bool VisitConstructExpr(const Expr *E) { 3412 Result.set(E, Info.CurrentCall); 3413 return EvaluateConstantExpression(Info.CurrentCall->Temporaries[E], Info, 3414 Result, E); 3415 } 3416 3417 bool VisitCastExpr(const CastExpr *E) { 3418 switch (E->getCastKind()) { 3419 default: 3420 return LValueExprEvaluatorBaseTy::VisitCastExpr(E); 3421 3422 case CK_ConstructorConversion: 3423 return VisitConstructExpr(E->getSubExpr()); 3424 } 3425 } 3426 bool VisitInitListExpr(const InitListExpr *E) { 3427 return VisitConstructExpr(E); 3428 } 3429 bool VisitCXXConstructExpr(const CXXConstructExpr *E) { 3430 return VisitConstructExpr(E); 3431 } 3432 bool VisitCallExpr(const CallExpr *E) { 3433 return VisitConstructExpr(E); 3434 } 3435}; 3436} // end anonymous namespace 3437 3438/// Evaluate an expression of record type as a temporary. 3439static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) { 3440 assert(E->isRValue() && E->getType()->isRecordType()); 3441 return TemporaryExprEvaluator(Info, Result).Visit(E); 3442} 3443 3444//===----------------------------------------------------------------------===// 3445// Vector Evaluation 3446//===----------------------------------------------------------------------===// 3447 3448namespace { 3449 class VectorExprEvaluator 3450 : public ExprEvaluatorBase<VectorExprEvaluator, bool> { 3451 APValue &Result; 3452 public: 3453 3454 VectorExprEvaluator(EvalInfo &info, APValue &Result) 3455 : ExprEvaluatorBaseTy(info), Result(Result) {} 3456 3457 bool Success(const ArrayRef<APValue> &V, const Expr *E) { 3458 assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements()); 3459 // FIXME: remove this APValue copy. 3460 Result = APValue(V.data(), V.size()); 3461 return true; 3462 } 3463 bool Success(const CCValue &V, const Expr *E) { 3464 assert(V.isVector()); 3465 Result = V; 3466 return true; 3467 } 3468 bool ZeroInitialization(const Expr *E); 3469 3470 bool VisitUnaryReal(const UnaryOperator *E) 3471 { return Visit(E->getSubExpr()); } 3472 bool VisitCastExpr(const CastExpr* E); 3473 bool VisitInitListExpr(const InitListExpr *E); 3474 bool VisitUnaryImag(const UnaryOperator *E); 3475 // FIXME: Missing: unary -, unary ~, binary add/sub/mul/div, 3476 // binary comparisons, binary and/or/xor, 3477 // shufflevector, ExtVectorElementExpr 3478 }; 3479} // end anonymous namespace 3480 3481static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) { 3482 assert(E->isRValue() && E->getType()->isVectorType() &&"not a vector rvalue"); 3483 return VectorExprEvaluator(Info, Result).Visit(E); 3484} 3485 3486bool VectorExprEvaluator::VisitCastExpr(const CastExpr* E) { 3487 const VectorType *VTy = E->getType()->castAs<VectorType>(); 3488 unsigned NElts = VTy->getNumElements(); 3489 3490 const Expr *SE = E->getSubExpr(); 3491 QualType SETy = SE->getType(); 3492 3493 switch (E->getCastKind()) { 3494 case CK_VectorSplat: { 3495 APValue Val = APValue(); 3496 if (SETy->isIntegerType()) { 3497 APSInt IntResult; 3498 if (!EvaluateInteger(SE, IntResult, Info)) 3499 return false; 3500 Val = APValue(IntResult); 3501 } else if (SETy->isRealFloatingType()) { 3502 APFloat F(0.0); 3503 if (!EvaluateFloat(SE, F, Info)) 3504 return false; 3505 Val = APValue(F); 3506 } else { 3507 return Error(E); 3508 } 3509 3510 // Splat and create vector APValue. 3511 SmallVector<APValue, 4> Elts(NElts, Val); 3512 return Success(Elts, E); 3513 } 3514 case CK_BitCast: { 3515 // Evaluate the operand into an APInt we can extract from. 3516 llvm::APInt SValInt; 3517 if (!EvalAndBitcastToAPInt(Info, SE, SValInt)) 3518 return false; 3519 // Extract the elements 3520 QualType EltTy = VTy->getElementType(); 3521 unsigned EltSize = Info.Ctx.getTypeSize(EltTy); 3522 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian(); 3523 SmallVector<APValue, 4> Elts; 3524 if (EltTy->isRealFloatingType()) { 3525 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy); 3526 bool isIEESem = &Sem != &APFloat::PPCDoubleDouble; 3527 unsigned FloatEltSize = EltSize; 3528 if (&Sem == &APFloat::x87DoubleExtended) 3529 FloatEltSize = 80; 3530 for (unsigned i = 0; i < NElts; i++) { 3531 llvm::APInt Elt; 3532 if (BigEndian) 3533 Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize); 3534 else 3535 Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize); 3536 Elts.push_back(APValue(APFloat(Elt, isIEESem))); 3537 } 3538 } else if (EltTy->isIntegerType()) { 3539 for (unsigned i = 0; i < NElts; i++) { 3540 llvm::APInt Elt; 3541 if (BigEndian) 3542 Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize); 3543 else 3544 Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize); 3545 Elts.push_back(APValue(APSInt(Elt, EltTy->isSignedIntegerType()))); 3546 } 3547 } else { 3548 return Error(E); 3549 } 3550 return Success(Elts, E); 3551 } 3552 default: 3553 return ExprEvaluatorBaseTy::VisitCastExpr(E); 3554 } 3555} 3556 3557bool 3558VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) { 3559 const VectorType *VT = E->getType()->castAs<VectorType>(); 3560 unsigned NumInits = E->getNumInits(); 3561 unsigned NumElements = VT->getNumElements(); 3562 3563 QualType EltTy = VT->getElementType(); 3564 SmallVector<APValue, 4> Elements; 3565 3566 // The number of initializers can be less than the number of 3567 // vector elements. For OpenCL, this can be due to nested vector 3568 // initialization. For GCC compatibility, missing trailing elements 3569 // should be initialized with zeroes. 3570 unsigned CountInits = 0, CountElts = 0; 3571 while (CountElts < NumElements) { 3572 // Handle nested vector initialization. 3573 if (CountInits < NumInits 3574 && E->getInit(CountInits)->getType()->isExtVectorType()) { 3575 APValue v; 3576 if (!EvaluateVector(E->getInit(CountInits), v, Info)) 3577 return Error(E); 3578 unsigned vlen = v.getVectorLength(); 3579 for (unsigned j = 0; j < vlen; j++) 3580 Elements.push_back(v.getVectorElt(j)); 3581 CountElts += vlen; 3582 } else if (EltTy->isIntegerType()) { 3583 llvm::APSInt sInt(32); 3584 if (CountInits < NumInits) { 3585 if (!EvaluateInteger(E->getInit(CountInits), sInt, Info)) 3586 return Error(E); 3587 } else // trailing integer zero. 3588 sInt = Info.Ctx.MakeIntValue(0, EltTy); 3589 Elements.push_back(APValue(sInt)); 3590 CountElts++; 3591 } else { 3592 llvm::APFloat f(0.0); 3593 if (CountInits < NumInits) { 3594 if (!EvaluateFloat(E->getInit(CountInits), f, Info)) 3595 return Error(E); 3596 } else // trailing float zero. 3597 f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)); 3598 Elements.push_back(APValue(f)); 3599 CountElts++; 3600 } 3601 CountInits++; 3602 } 3603 return Success(Elements, E); 3604} 3605 3606bool 3607VectorExprEvaluator::ZeroInitialization(const Expr *E) { 3608 const VectorType *VT = E->getType()->getAs<VectorType>(); 3609 QualType EltTy = VT->getElementType(); 3610 APValue ZeroElement; 3611 if (EltTy->isIntegerType()) 3612 ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy)); 3613 else 3614 ZeroElement = 3615 APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy))); 3616 3617 SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement); 3618 return Success(Elements, E); 3619} 3620 3621bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { 3622 VisitIgnoredValue(E->getSubExpr()); 3623 return ZeroInitialization(E); 3624} 3625 3626//===----------------------------------------------------------------------===// 3627// Array Evaluation 3628//===----------------------------------------------------------------------===// 3629 3630namespace { 3631 class ArrayExprEvaluator 3632 : public ExprEvaluatorBase<ArrayExprEvaluator, bool> { 3633 const LValue &This; 3634 APValue &Result; 3635 public: 3636 3637 ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result) 3638 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {} 3639 3640 bool Success(const APValue &V, const Expr *E) { 3641 assert(V.isArray() && "Expected array type"); 3642 Result = V; 3643 return true; 3644 } 3645 3646 bool ZeroInitialization(const Expr *E) { 3647 const ConstantArrayType *CAT = 3648 Info.Ctx.getAsConstantArrayType(E->getType()); 3649 if (!CAT) 3650 return Error(E); 3651 3652 Result = APValue(APValue::UninitArray(), 0, 3653 CAT->getSize().getZExtValue()); 3654 if (!Result.hasArrayFiller()) return true; 3655 3656 // Zero-initialize all elements. 3657 LValue Subobject = This; 3658 Subobject.addArray(Info, E, CAT); 3659 ImplicitValueInitExpr VIE(CAT->getElementType()); 3660 return EvaluateConstantExpression(Result.getArrayFiller(), Info, 3661 Subobject, &VIE); 3662 } 3663 3664 bool VisitInitListExpr(const InitListExpr *E); 3665 bool VisitCXXConstructExpr(const CXXConstructExpr *E); 3666 }; 3667} // end anonymous namespace 3668 3669static bool EvaluateArray(const Expr *E, const LValue &This, 3670 APValue &Result, EvalInfo &Info) { 3671 assert(E->isRValue() && E->getType()->isArrayType() && "not an array rvalue"); 3672 return ArrayExprEvaluator(Info, This, Result).Visit(E); 3673} 3674 3675bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E) { 3676 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(E->getType()); 3677 if (!CAT) 3678 return Error(E); 3679 3680 // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...] 3681 // an appropriately-typed string literal enclosed in braces. 3682 if (E->getNumInits() == 1 && E->getInit(0)->isGLValue() && 3683 Info.Ctx.hasSameUnqualifiedType(E->getType(), E->getInit(0)->getType())) { 3684 LValue LV; 3685 if (!EvaluateLValue(E->getInit(0), LV, Info)) 3686 return false; 3687 uint64_t NumElements = CAT->getSize().getZExtValue(); 3688 Result = APValue(APValue::UninitArray(), NumElements, NumElements); 3689 3690 // Copy the string literal into the array. FIXME: Do this better. 3691 LV.addArray(Info, E, CAT); 3692 for (uint64_t I = 0; I < NumElements; ++I) { 3693 CCValue Char; 3694 if (!HandleLValueToRValueConversion(Info, E->getInit(0), 3695 CAT->getElementType(), LV, Char) || 3696 !CheckConstantExpression(Info, E->getInit(0), Char, 3697 Result.getArrayInitializedElt(I)) || 3698 !HandleLValueArrayAdjustment(Info, E->getInit(0), LV, 3699 CAT->getElementType(), 1)) 3700 return false; 3701 } 3702 return true; 3703 } 3704 3705 bool Success = true; 3706 3707 Result = APValue(APValue::UninitArray(), E->getNumInits(), 3708 CAT->getSize().getZExtValue()); 3709 LValue Subobject = This; 3710 Subobject.addArray(Info, E, CAT); 3711 unsigned Index = 0; 3712 for (InitListExpr::const_iterator I = E->begin(), End = E->end(); 3713 I != End; ++I, ++Index) { 3714 if (!EvaluateConstantExpression(Result.getArrayInitializedElt(Index), 3715 Info, Subobject, cast<Expr>(*I)) || 3716 !HandleLValueArrayAdjustment(Info, cast<Expr>(*I), Subobject, 3717 CAT->getElementType(), 1)) { 3718 if (!Info.keepEvaluatingAfterFailure()) 3719 return false; 3720 Success = false; 3721 } 3722 } 3723 3724 if (!Result.hasArrayFiller()) return Success; 3725 assert(E->hasArrayFiller() && "no array filler for incomplete init list"); 3726 // FIXME: The Subobject here isn't necessarily right. This rarely matters, 3727 // but sometimes does: 3728 // struct S { constexpr S() : p(&p) {} void *p; }; 3729 // S s[10] = {}; 3730 return EvaluateConstantExpression(Result.getArrayFiller(), Info, 3731 Subobject, E->getArrayFiller()) && Success; 3732} 3733 3734bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) { 3735 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(E->getType()); 3736 if (!CAT) 3737 return Error(E); 3738 3739 bool HadZeroInit = !Result.isUninit(); 3740 if (!HadZeroInit) 3741 Result = APValue(APValue::UninitArray(), 0, CAT->getSize().getZExtValue()); 3742 if (!Result.hasArrayFiller()) 3743 return true; 3744 3745 const CXXConstructorDecl *FD = E->getConstructor(); 3746 3747 bool ZeroInit = E->requiresZeroInitialization(); 3748 if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) { 3749 if (HadZeroInit) 3750 return true; 3751 3752 if (ZeroInit) { 3753 LValue Subobject = This; 3754 Subobject.addArray(Info, E, CAT); 3755 ImplicitValueInitExpr VIE(CAT->getElementType()); 3756 return EvaluateConstantExpression(Result.getArrayFiller(), Info, 3757 Subobject, &VIE); 3758 } 3759 3760 const CXXRecordDecl *RD = FD->getParent(); 3761 if (RD->isUnion()) 3762 Result.getArrayFiller() = APValue((FieldDecl*)0); 3763 else 3764 Result.getArrayFiller() = 3765 APValue(APValue::UninitStruct(), RD->getNumBases(), 3766 std::distance(RD->field_begin(), RD->field_end())); 3767 return true; 3768 } 3769 3770 const FunctionDecl *Definition = 0; 3771 FD->getBody(Definition); 3772 3773 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition)) 3774 return false; 3775 3776 // FIXME: The Subobject here isn't necessarily right. This rarely matters, 3777 // but sometimes does: 3778 // struct S { constexpr S() : p(&p) {} void *p; }; 3779 // S s[10]; 3780 LValue Subobject = This; 3781 Subobject.addArray(Info, E, CAT); 3782 3783 if (ZeroInit && !HadZeroInit) { 3784 ImplicitValueInitExpr VIE(CAT->getElementType()); 3785 if (!EvaluateConstantExpression(Result.getArrayFiller(), Info, Subobject, 3786 &VIE)) 3787 return false; 3788 } 3789 3790 llvm::ArrayRef<const Expr*> Args(E->getArgs(), E->getNumArgs()); 3791 return HandleConstructorCall(E->getExprLoc(), Subobject, Args, 3792 cast<CXXConstructorDecl>(Definition), 3793 Info, Result.getArrayFiller()); 3794} 3795 3796//===----------------------------------------------------------------------===// 3797// Integer Evaluation 3798// 3799// As a GNU extension, we support casting pointers to sufficiently-wide integer 3800// types and back in constant folding. Integer values are thus represented 3801// either as an integer-valued APValue, or as an lvalue-valued APValue. 3802//===----------------------------------------------------------------------===// 3803 3804namespace { 3805class IntExprEvaluator 3806 : public ExprEvaluatorBase<IntExprEvaluator, bool> { 3807 CCValue &Result; 3808public: 3809 IntExprEvaluator(EvalInfo &info, CCValue &result) 3810 : ExprEvaluatorBaseTy(info), Result(result) {} 3811 3812 bool Success(const llvm::APSInt &SI, const Expr *E) { 3813 assert(E->getType()->isIntegralOrEnumerationType() && 3814 "Invalid evaluation result."); 3815 assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() && 3816 "Invalid evaluation result."); 3817 assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && 3818 "Invalid evaluation result."); 3819 Result = CCValue(SI); 3820 return true; 3821 } 3822 3823 bool Success(const llvm::APInt &I, const Expr *E) { 3824 assert(E->getType()->isIntegralOrEnumerationType() && 3825 "Invalid evaluation result."); 3826 assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && 3827 "Invalid evaluation result."); 3828 Result = CCValue(APSInt(I)); 3829 Result.getInt().setIsUnsigned( 3830 E->getType()->isUnsignedIntegerOrEnumerationType()); 3831 return true; 3832 } 3833 3834 bool Success(uint64_t Value, const Expr *E) { 3835 assert(E->getType()->isIntegralOrEnumerationType() && 3836 "Invalid evaluation result."); 3837 Result = CCValue(Info.Ctx.MakeIntValue(Value, E->getType())); 3838 return true; 3839 } 3840 3841 bool Success(CharUnits Size, const Expr *E) { 3842 return Success(Size.getQuantity(), E); 3843 } 3844 3845 bool Success(const CCValue &V, const Expr *E) { 3846 if (V.isLValue() || V.isAddrLabelDiff()) { 3847 Result = V; 3848 return true; 3849 } 3850 return Success(V.getInt(), E); 3851 } 3852 3853 bool ZeroInitialization(const Expr *E) { return Success(0, E); } 3854 3855 //===--------------------------------------------------------------------===// 3856 // Visitor Methods 3857 //===--------------------------------------------------------------------===// 3858 3859 bool VisitIntegerLiteral(const IntegerLiteral *E) { 3860 return Success(E->getValue(), E); 3861 } 3862 bool VisitCharacterLiteral(const CharacterLiteral *E) { 3863 return Success(E->getValue(), E); 3864 } 3865 3866 bool CheckReferencedDecl(const Expr *E, const Decl *D); 3867 bool VisitDeclRefExpr(const DeclRefExpr *E) { 3868 if (CheckReferencedDecl(E, E->getDecl())) 3869 return true; 3870 3871 return ExprEvaluatorBaseTy::VisitDeclRefExpr(E); 3872 } 3873 bool VisitMemberExpr(const MemberExpr *E) { 3874 if (CheckReferencedDecl(E, E->getMemberDecl())) { 3875 VisitIgnoredValue(E->getBase()); 3876 return true; 3877 } 3878 3879 return ExprEvaluatorBaseTy::VisitMemberExpr(E); 3880 } 3881 3882 bool VisitCallExpr(const CallExpr *E); 3883 bool VisitBinaryOperator(const BinaryOperator *E); 3884 bool VisitOffsetOfExpr(const OffsetOfExpr *E); 3885 bool VisitUnaryOperator(const UnaryOperator *E); 3886 3887 bool VisitCastExpr(const CastExpr* E); 3888 bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E); 3889 3890 bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) { 3891 return Success(E->getValue(), E); 3892 } 3893 3894 // Note, GNU defines __null as an integer, not a pointer. 3895 bool VisitGNUNullExpr(const GNUNullExpr *E) { 3896 return ZeroInitialization(E); 3897 } 3898 3899 bool VisitUnaryTypeTraitExpr(const UnaryTypeTraitExpr *E) { 3900 return Success(E->getValue(), E); 3901 } 3902 3903 bool VisitBinaryTypeTraitExpr(const BinaryTypeTraitExpr *E) { 3904 return Success(E->getValue(), E); 3905 } 3906 3907 bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) { 3908 return Success(E->getValue(), E); 3909 } 3910 3911 bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) { 3912 return Success(E->getValue(), E); 3913 } 3914 3915 bool VisitUnaryReal(const UnaryOperator *E); 3916 bool VisitUnaryImag(const UnaryOperator *E); 3917 3918 bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E); 3919 bool VisitSizeOfPackExpr(const SizeOfPackExpr *E); 3920 3921private: 3922 CharUnits GetAlignOfExpr(const Expr *E); 3923 CharUnits GetAlignOfType(QualType T); 3924 static QualType GetObjectType(APValue::LValueBase B); 3925 bool TryEvaluateBuiltinObjectSize(const CallExpr *E); 3926 // FIXME: Missing: array subscript of vector, member of vector 3927}; 3928} // end anonymous namespace 3929 3930/// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and 3931/// produce either the integer value or a pointer. 3932/// 3933/// GCC has a heinous extension which folds casts between pointer types and 3934/// pointer-sized integral types. We support this by allowing the evaluation of 3935/// an integer rvalue to produce a pointer (represented as an lvalue) instead. 3936/// Some simple arithmetic on such values is supported (they are treated much 3937/// like char*). 3938static bool EvaluateIntegerOrLValue(const Expr *E, CCValue &Result, 3939 EvalInfo &Info) { 3940 assert(E->isRValue() && E->getType()->isIntegralOrEnumerationType()); 3941 return IntExprEvaluator(Info, Result).Visit(E); 3942} 3943 3944static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) { 3945 CCValue Val; 3946 if (!EvaluateIntegerOrLValue(E, Val, Info)) 3947 return false; 3948 if (!Val.isInt()) { 3949 // FIXME: It would be better to produce the diagnostic for casting 3950 // a pointer to an integer. 3951 Info.Diag(E->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 3952 return false; 3953 } 3954 Result = Val.getInt(); 3955 return true; 3956} 3957 3958/// Check whether the given declaration can be directly converted to an integral 3959/// rvalue. If not, no diagnostic is produced; there are other things we can 3960/// try. 3961bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) { 3962 // Enums are integer constant exprs. 3963 if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) { 3964 // Check for signedness/width mismatches between E type and ECD value. 3965 bool SameSign = (ECD->getInitVal().isSigned() 3966 == E->getType()->isSignedIntegerOrEnumerationType()); 3967 bool SameWidth = (ECD->getInitVal().getBitWidth() 3968 == Info.Ctx.getIntWidth(E->getType())); 3969 if (SameSign && SameWidth) 3970 return Success(ECD->getInitVal(), E); 3971 else { 3972 // Get rid of mismatch (otherwise Success assertions will fail) 3973 // by computing a new value matching the type of E. 3974 llvm::APSInt Val = ECD->getInitVal(); 3975 if (!SameSign) 3976 Val.setIsSigned(!ECD->getInitVal().isSigned()); 3977 if (!SameWidth) 3978 Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType())); 3979 return Success(Val, E); 3980 } 3981 } 3982 return false; 3983} 3984 3985/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way 3986/// as GCC. 3987static int EvaluateBuiltinClassifyType(const CallExpr *E) { 3988 // The following enum mimics the values returned by GCC. 3989 // FIXME: Does GCC differ between lvalue and rvalue references here? 3990 enum gcc_type_class { 3991 no_type_class = -1, 3992 void_type_class, integer_type_class, char_type_class, 3993 enumeral_type_class, boolean_type_class, 3994 pointer_type_class, reference_type_class, offset_type_class, 3995 real_type_class, complex_type_class, 3996 function_type_class, method_type_class, 3997 record_type_class, union_type_class, 3998 array_type_class, string_type_class, 3999 lang_type_class 4000 }; 4001 4002 // If no argument was supplied, default to "no_type_class". This isn't 4003 // ideal, however it is what gcc does. 4004 if (E->getNumArgs() == 0) 4005 return no_type_class; 4006 4007 QualType ArgTy = E->getArg(0)->getType(); 4008 if (ArgTy->isVoidType()) 4009 return void_type_class; 4010 else if (ArgTy->isEnumeralType()) 4011 return enumeral_type_class; 4012 else if (ArgTy->isBooleanType()) 4013 return boolean_type_class; 4014 else if (ArgTy->isCharType()) 4015 return string_type_class; // gcc doesn't appear to use char_type_class 4016 else if (ArgTy->isIntegerType()) 4017 return integer_type_class; 4018 else if (ArgTy->isPointerType()) 4019 return pointer_type_class; 4020 else if (ArgTy->isReferenceType()) 4021 return reference_type_class; 4022 else if (ArgTy->isRealType()) 4023 return real_type_class; 4024 else if (ArgTy->isComplexType()) 4025 return complex_type_class; 4026 else if (ArgTy->isFunctionType()) 4027 return function_type_class; 4028 else if (ArgTy->isStructureOrClassType()) 4029 return record_type_class; 4030 else if (ArgTy->isUnionType()) 4031 return union_type_class; 4032 else if (ArgTy->isArrayType()) 4033 return array_type_class; 4034 else if (ArgTy->isUnionType()) 4035 return union_type_class; 4036 else // FIXME: offset_type_class, method_type_class, & lang_type_class? 4037 llvm_unreachable("CallExpr::isBuiltinClassifyType(): unimplemented type"); 4038} 4039 4040/// EvaluateBuiltinConstantPForLValue - Determine the result of 4041/// __builtin_constant_p when applied to the given lvalue. 4042/// 4043/// An lvalue is only "constant" if it is a pointer or reference to the first 4044/// character of a string literal. 4045template<typename LValue> 4046static bool EvaluateBuiltinConstantPForLValue(const LValue &LV) { 4047 const Expr *E = LV.getLValueBase().dyn_cast<const Expr*>(); 4048 return E && isa<StringLiteral>(E) && LV.getLValueOffset().isZero(); 4049} 4050 4051/// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to 4052/// GCC as we can manage. 4053static bool EvaluateBuiltinConstantP(ASTContext &Ctx, const Expr *Arg) { 4054 QualType ArgType = Arg->getType(); 4055 4056 // __builtin_constant_p always has one operand. The rules which gcc follows 4057 // are not precisely documented, but are as follows: 4058 // 4059 // - If the operand is of integral, floating, complex or enumeration type, 4060 // and can be folded to a known value of that type, it returns 1. 4061 // - If the operand and can be folded to a pointer to the first character 4062 // of a string literal (or such a pointer cast to an integral type), it 4063 // returns 1. 4064 // 4065 // Otherwise, it returns 0. 4066 // 4067 // FIXME: GCC also intends to return 1 for literals of aggregate types, but 4068 // its support for this does not currently work. 4069 if (ArgType->isIntegralOrEnumerationType()) { 4070 Expr::EvalResult Result; 4071 if (!Arg->EvaluateAsRValue(Result, Ctx) || Result.HasSideEffects) 4072 return false; 4073 4074 APValue &V = Result.Val; 4075 if (V.getKind() == APValue::Int) 4076 return true; 4077 4078 return EvaluateBuiltinConstantPForLValue(V); 4079 } else if (ArgType->isFloatingType() || ArgType->isAnyComplexType()) { 4080 return Arg->isEvaluatable(Ctx); 4081 } else if (ArgType->isPointerType() || Arg->isGLValue()) { 4082 LValue LV; 4083 Expr::EvalStatus Status; 4084 EvalInfo Info(Ctx, Status); 4085 if ((Arg->isGLValue() ? EvaluateLValue(Arg, LV, Info) 4086 : EvaluatePointer(Arg, LV, Info)) && 4087 !Status.HasSideEffects) 4088 return EvaluateBuiltinConstantPForLValue(LV); 4089 } 4090 4091 // Anything else isn't considered to be sufficiently constant. 4092 return false; 4093} 4094 4095/// Retrieves the "underlying object type" of the given expression, 4096/// as used by __builtin_object_size. 4097QualType IntExprEvaluator::GetObjectType(APValue::LValueBase B) { 4098 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) { 4099 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 4100 return VD->getType(); 4101 } else if (const Expr *E = B.get<const Expr*>()) { 4102 if (isa<CompoundLiteralExpr>(E)) 4103 return E->getType(); 4104 } 4105 4106 return QualType(); 4107} 4108 4109bool IntExprEvaluator::TryEvaluateBuiltinObjectSize(const CallExpr *E) { 4110 // TODO: Perhaps we should let LLVM lower this? 4111 LValue Base; 4112 if (!EvaluatePointer(E->getArg(0), Base, Info)) 4113 return false; 4114 4115 // If we can prove the base is null, lower to zero now. 4116 if (!Base.getLValueBase()) return Success(0, E); 4117 4118 QualType T = GetObjectType(Base.getLValueBase()); 4119 if (T.isNull() || 4120 T->isIncompleteType() || 4121 T->isFunctionType() || 4122 T->isVariablyModifiedType() || 4123 T->isDependentType()) 4124 return Error(E); 4125 4126 CharUnits Size = Info.Ctx.getTypeSizeInChars(T); 4127 CharUnits Offset = Base.getLValueOffset(); 4128 4129 if (!Offset.isNegative() && Offset <= Size) 4130 Size -= Offset; 4131 else 4132 Size = CharUnits::Zero(); 4133 return Success(Size, E); 4134} 4135 4136bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) { 4137 switch (E->isBuiltinCall()) { 4138 default: 4139 return ExprEvaluatorBaseTy::VisitCallExpr(E); 4140 4141 case Builtin::BI__builtin_object_size: { 4142 if (TryEvaluateBuiltinObjectSize(E)) 4143 return true; 4144 4145 // If evaluating the argument has side-effects we can't determine 4146 // the size of the object and lower it to unknown now. 4147 if (E->getArg(0)->HasSideEffects(Info.Ctx)) { 4148 if (E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue() <= 1) 4149 return Success(-1ULL, E); 4150 return Success(0, E); 4151 } 4152 4153 return Error(E); 4154 } 4155 4156 case Builtin::BI__builtin_classify_type: 4157 return Success(EvaluateBuiltinClassifyType(E), E); 4158 4159 case Builtin::BI__builtin_constant_p: 4160 return Success(EvaluateBuiltinConstantP(Info.Ctx, E->getArg(0)), E); 4161 4162 case Builtin::BI__builtin_eh_return_data_regno: { 4163 int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue(); 4164 Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand); 4165 return Success(Operand, E); 4166 } 4167 4168 case Builtin::BI__builtin_expect: 4169 return Visit(E->getArg(0)); 4170 4171 case Builtin::BIstrlen: 4172 // A call to strlen is not a constant expression. 4173 if (Info.getLangOpts().CPlusPlus0x) 4174 Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_invalid_function) 4175 << /*isConstexpr*/0 << /*isConstructor*/0 << "'strlen'"; 4176 else 4177 Info.CCEDiag(E->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 4178 // Fall through. 4179 case Builtin::BI__builtin_strlen: 4180 // As an extension, we support strlen() and __builtin_strlen() as constant 4181 // expressions when the argument is a string literal. 4182 if (const StringLiteral *S 4183 = dyn_cast<StringLiteral>(E->getArg(0)->IgnoreParenImpCasts())) { 4184 // The string literal may have embedded null characters. Find the first 4185 // one and truncate there. 4186 StringRef Str = S->getString(); 4187 StringRef::size_type Pos = Str.find(0); 4188 if (Pos != StringRef::npos) 4189 Str = Str.substr(0, Pos); 4190 4191 return Success(Str.size(), E); 4192 } 4193 4194 return Error(E); 4195 4196 case Builtin::BI__atomic_is_lock_free: { 4197 APSInt SizeVal; 4198 if (!EvaluateInteger(E->getArg(0), SizeVal, Info)) 4199 return false; 4200 4201 // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power 4202 // of two less than the maximum inline atomic width, we know it is 4203 // lock-free. If the size isn't a power of two, or greater than the 4204 // maximum alignment where we promote atomics, we know it is not lock-free 4205 // (at least not in the sense of atomic_is_lock_free). Otherwise, 4206 // the answer can only be determined at runtime; for example, 16-byte 4207 // atomics have lock-free implementations on some, but not all, 4208 // x86-64 processors. 4209 4210 // Check power-of-two. 4211 CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue()); 4212 if (!Size.isPowerOfTwo()) 4213#if 0 4214 // FIXME: Suppress this folding until the ABI for the promotion width 4215 // settles. 4216 return Success(0, E); 4217#else 4218 return Error(E); 4219#endif 4220 4221#if 0 4222 // Check against promotion width. 4223 // FIXME: Suppress this folding until the ABI for the promotion width 4224 // settles. 4225 unsigned PromoteWidthBits = 4226 Info.Ctx.getTargetInfo().getMaxAtomicPromoteWidth(); 4227 if (Size > Info.Ctx.toCharUnitsFromBits(PromoteWidthBits)) 4228 return Success(0, E); 4229#endif 4230 4231 // Check against inlining width. 4232 unsigned InlineWidthBits = 4233 Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth(); 4234 if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) 4235 return Success(1, E); 4236 4237 return Error(E); 4238 } 4239 } 4240} 4241 4242static bool HasSameBase(const LValue &A, const LValue &B) { 4243 if (!A.getLValueBase()) 4244 return !B.getLValueBase(); 4245 if (!B.getLValueBase()) 4246 return false; 4247 4248 if (A.getLValueBase().getOpaqueValue() != 4249 B.getLValueBase().getOpaqueValue()) { 4250 const Decl *ADecl = GetLValueBaseDecl(A); 4251 if (!ADecl) 4252 return false; 4253 const Decl *BDecl = GetLValueBaseDecl(B); 4254 if (!BDecl || ADecl->getCanonicalDecl() != BDecl->getCanonicalDecl()) 4255 return false; 4256 } 4257 4258 return IsGlobalLValue(A.getLValueBase()) || 4259 A.getLValueFrame() == B.getLValueFrame(); 4260} 4261 4262/// Perform the given integer operation, which is known to need at most BitWidth 4263/// bits, and check for overflow in the original type (if that type was not an 4264/// unsigned type). 4265template<typename Operation> 4266static APSInt CheckedIntArithmetic(EvalInfo &Info, const Expr *E, 4267 const APSInt &LHS, const APSInt &RHS, 4268 unsigned BitWidth, Operation Op) { 4269 if (LHS.isUnsigned()) 4270 return Op(LHS, RHS); 4271 4272 APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false); 4273 APSInt Result = Value.trunc(LHS.getBitWidth()); 4274 if (Result.extend(BitWidth) != Value) 4275 HandleOverflow(Info, E, Value, E->getType()); 4276 return Result; 4277} 4278 4279bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 4280 if (E->isAssignmentOp()) 4281 return Error(E); 4282 4283 if (E->getOpcode() == BO_Comma) { 4284 VisitIgnoredValue(E->getLHS()); 4285 return Visit(E->getRHS()); 4286 } 4287 4288 if (E->isLogicalOp()) { 4289 // These need to be handled specially because the operands aren't 4290 // necessarily integral 4291 bool lhsResult, rhsResult; 4292 4293 if (EvaluateAsBooleanCondition(E->getLHS(), lhsResult, Info)) { 4294 // We were able to evaluate the LHS, see if we can get away with not 4295 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1 4296 if (lhsResult == (E->getOpcode() == BO_LOr)) 4297 return Success(lhsResult, E); 4298 4299 if (EvaluateAsBooleanCondition(E->getRHS(), rhsResult, Info)) { 4300 if (E->getOpcode() == BO_LOr) 4301 return Success(lhsResult || rhsResult, E); 4302 else 4303 return Success(lhsResult && rhsResult, E); 4304 } 4305 } else { 4306 // FIXME: If both evaluations fail, we should produce the diagnostic from 4307 // the LHS. If the LHS is non-constant and the RHS is unevaluatable, it's 4308 // less clear how to diagnose this. 4309 if (EvaluateAsBooleanCondition(E->getRHS(), rhsResult, Info)) { 4310 // We can't evaluate the LHS; however, sometimes the result 4311 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1. 4312 if (rhsResult == (E->getOpcode() == BO_LOr)) { 4313 // Since we weren't able to evaluate the left hand side, it 4314 // must have had side effects. 4315 Info.EvalStatus.HasSideEffects = true; 4316 4317 return Success(rhsResult, E); 4318 } 4319 } 4320 } 4321 4322 return false; 4323 } 4324 4325 QualType LHSTy = E->getLHS()->getType(); 4326 QualType RHSTy = E->getRHS()->getType(); 4327 4328 if (LHSTy->isAnyComplexType()) { 4329 assert(RHSTy->isAnyComplexType() && "Invalid comparison"); 4330 ComplexValue LHS, RHS; 4331 4332 bool LHSOK = EvaluateComplex(E->getLHS(), LHS, Info); 4333 if (!LHSOK && !Info.keepEvaluatingAfterFailure()) 4334 return false; 4335 4336 if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK) 4337 return false; 4338 4339 if (LHS.isComplexFloat()) { 4340 APFloat::cmpResult CR_r = 4341 LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal()); 4342 APFloat::cmpResult CR_i = 4343 LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag()); 4344 4345 if (E->getOpcode() == BO_EQ) 4346 return Success((CR_r == APFloat::cmpEqual && 4347 CR_i == APFloat::cmpEqual), E); 4348 else { 4349 assert(E->getOpcode() == BO_NE && 4350 "Invalid complex comparison."); 4351 return Success(((CR_r == APFloat::cmpGreaterThan || 4352 CR_r == APFloat::cmpLessThan || 4353 CR_r == APFloat::cmpUnordered) || 4354 (CR_i == APFloat::cmpGreaterThan || 4355 CR_i == APFloat::cmpLessThan || 4356 CR_i == APFloat::cmpUnordered)), E); 4357 } 4358 } else { 4359 if (E->getOpcode() == BO_EQ) 4360 return Success((LHS.getComplexIntReal() == RHS.getComplexIntReal() && 4361 LHS.getComplexIntImag() == RHS.getComplexIntImag()), E); 4362 else { 4363 assert(E->getOpcode() == BO_NE && 4364 "Invalid compex comparison."); 4365 return Success((LHS.getComplexIntReal() != RHS.getComplexIntReal() || 4366 LHS.getComplexIntImag() != RHS.getComplexIntImag()), E); 4367 } 4368 } 4369 } 4370 4371 if (LHSTy->isRealFloatingType() && 4372 RHSTy->isRealFloatingType()) { 4373 APFloat RHS(0.0), LHS(0.0); 4374 4375 bool LHSOK = EvaluateFloat(E->getRHS(), RHS, Info); 4376 if (!LHSOK && !Info.keepEvaluatingAfterFailure()) 4377 return false; 4378 4379 if (!EvaluateFloat(E->getLHS(), LHS, Info) || !LHSOK) 4380 return false; 4381 4382 APFloat::cmpResult CR = LHS.compare(RHS); 4383 4384 switch (E->getOpcode()) { 4385 default: 4386 llvm_unreachable("Invalid binary operator!"); 4387 case BO_LT: 4388 return Success(CR == APFloat::cmpLessThan, E); 4389 case BO_GT: 4390 return Success(CR == APFloat::cmpGreaterThan, E); 4391 case BO_LE: 4392 return Success(CR == APFloat::cmpLessThan || CR == APFloat::cmpEqual, E); 4393 case BO_GE: 4394 return Success(CR == APFloat::cmpGreaterThan || CR == APFloat::cmpEqual, 4395 E); 4396 case BO_EQ: 4397 return Success(CR == APFloat::cmpEqual, E); 4398 case BO_NE: 4399 return Success(CR == APFloat::cmpGreaterThan 4400 || CR == APFloat::cmpLessThan 4401 || CR == APFloat::cmpUnordered, E); 4402 } 4403 } 4404 4405 if (LHSTy->isPointerType() && RHSTy->isPointerType()) { 4406 if (E->getOpcode() == BO_Sub || E->isComparisonOp()) { 4407 LValue LHSValue, RHSValue; 4408 4409 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info); 4410 if (!LHSOK && Info.keepEvaluatingAfterFailure()) 4411 return false; 4412 4413 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK) 4414 return false; 4415 4416 // Reject differing bases from the normal codepath; we special-case 4417 // comparisons to null. 4418 if (!HasSameBase(LHSValue, RHSValue)) { 4419 if (E->getOpcode() == BO_Sub) { 4420 // Handle &&A - &&B. 4421 if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero()) 4422 return false; 4423 const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr*>(); 4424 const Expr *RHSExpr = LHSValue.Base.dyn_cast<const Expr*>(); 4425 if (!LHSExpr || !RHSExpr) 4426 return false; 4427 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr); 4428 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr); 4429 if (!LHSAddrExpr || !RHSAddrExpr) 4430 return false; 4431 // Make sure both labels come from the same function. 4432 if (LHSAddrExpr->getLabel()->getDeclContext() != 4433 RHSAddrExpr->getLabel()->getDeclContext()) 4434 return false; 4435 Result = CCValue(LHSAddrExpr, RHSAddrExpr); 4436 return true; 4437 } 4438 // Inequalities and subtractions between unrelated pointers have 4439 // unspecified or undefined behavior. 4440 if (!E->isEqualityOp()) 4441 return Error(E); 4442 // A constant address may compare equal to the address of a symbol. 4443 // The one exception is that address of an object cannot compare equal 4444 // to a null pointer constant. 4445 if ((!LHSValue.Base && !LHSValue.Offset.isZero()) || 4446 (!RHSValue.Base && !RHSValue.Offset.isZero())) 4447 return Error(E); 4448 // It's implementation-defined whether distinct literals will have 4449 // distinct addresses. In clang, the result of such a comparison is 4450 // unspecified, so it is not a constant expression. However, we do know 4451 // that the address of a literal will be non-null. 4452 if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) && 4453 LHSValue.Base && RHSValue.Base) 4454 return Error(E); 4455 // We can't tell whether weak symbols will end up pointing to the same 4456 // object. 4457 if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue)) 4458 return Error(E); 4459 // Pointers with different bases cannot represent the same object. 4460 // (Note that clang defaults to -fmerge-all-constants, which can 4461 // lead to inconsistent results for comparisons involving the address 4462 // of a constant; this generally doesn't matter in practice.) 4463 return Success(E->getOpcode() == BO_NE, E); 4464 } 4465 4466 const CharUnits &LHSOffset = LHSValue.getLValueOffset(); 4467 const CharUnits &RHSOffset = RHSValue.getLValueOffset(); 4468 4469 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator(); 4470 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator(); 4471 4472 if (E->getOpcode() == BO_Sub) { 4473 // C++11 [expr.add]p6: 4474 // Unless both pointers point to elements of the same array object, or 4475 // one past the last element of the array object, the behavior is 4476 // undefined. 4477 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && 4478 !AreElementsOfSameArray(getType(LHSValue.Base), 4479 LHSDesignator, RHSDesignator)) 4480 CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array); 4481 4482 QualType Type = E->getLHS()->getType(); 4483 QualType ElementType = Type->getAs<PointerType>()->getPointeeType(); 4484 4485 CharUnits ElementSize; 4486 if (!HandleSizeof(Info, ElementType, ElementSize)) 4487 return false; 4488 4489 // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime, 4490 // and produce incorrect results when it overflows. Such behavior 4491 // appears to be non-conforming, but is common, so perhaps we should 4492 // assume the standard intended for such cases to be undefined behavior 4493 // and check for them. 4494 4495 // Compute (LHSOffset - RHSOffset) / Size carefully, checking for 4496 // overflow in the final conversion to ptrdiff_t. 4497 APSInt LHS( 4498 llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false); 4499 APSInt RHS( 4500 llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false); 4501 APSInt ElemSize( 4502 llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true), false); 4503 APSInt TrueResult = (LHS - RHS) / ElemSize; 4504 APSInt Result = TrueResult.trunc(Info.Ctx.getIntWidth(E->getType())); 4505 4506 if (Result.extend(65) != TrueResult) 4507 HandleOverflow(Info, E, TrueResult, E->getType()); 4508 return Success(Result, E); 4509 } 4510 4511 // C++11 [expr.rel]p3: 4512 // Pointers to void (after pointer conversions) can be compared, with a 4513 // result defined as follows: If both pointers represent the same 4514 // address or are both the null pointer value, the result is true if the 4515 // operator is <= or >= and false otherwise; otherwise the result is 4516 // unspecified. 4517 // We interpret this as applying to pointers to *cv* void. 4518 if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset && 4519 E->isRelationalOp()) 4520 CCEDiag(E, diag::note_constexpr_void_comparison); 4521 4522 // C++11 [expr.rel]p2: 4523 // - If two pointers point to non-static data members of the same object, 4524 // or to subobjects or array elements fo such members, recursively, the 4525 // pointer to the later declared member compares greater provided the 4526 // two members have the same access control and provided their class is 4527 // not a union. 4528 // [...] 4529 // - Otherwise pointer comparisons are unspecified. 4530 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && 4531 E->isRelationalOp()) { 4532 bool WasArrayIndex; 4533 unsigned Mismatch = 4534 FindDesignatorMismatch(getType(LHSValue.Base), LHSDesignator, 4535 RHSDesignator, WasArrayIndex); 4536 // At the point where the designators diverge, the comparison has a 4537 // specified value if: 4538 // - we are comparing array indices 4539 // - we are comparing fields of a union, or fields with the same access 4540 // Otherwise, the result is unspecified and thus the comparison is not a 4541 // constant expression. 4542 if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() && 4543 Mismatch < RHSDesignator.Entries.size()) { 4544 const FieldDecl *LF = getAsField(LHSDesignator.Entries[Mismatch]); 4545 const FieldDecl *RF = getAsField(RHSDesignator.Entries[Mismatch]); 4546 if (!LF && !RF) 4547 CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes); 4548 else if (!LF) 4549 CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field) 4550 << getAsBaseClass(LHSDesignator.Entries[Mismatch]) 4551 << RF->getParent() << RF; 4552 else if (!RF) 4553 CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field) 4554 << getAsBaseClass(RHSDesignator.Entries[Mismatch]) 4555 << LF->getParent() << LF; 4556 else if (!LF->getParent()->isUnion() && 4557 LF->getAccess() != RF->getAccess()) 4558 CCEDiag(E, diag::note_constexpr_pointer_comparison_differing_access) 4559 << LF << LF->getAccess() << RF << RF->getAccess() 4560 << LF->getParent(); 4561 } 4562 } 4563 4564 switch (E->getOpcode()) { 4565 default: llvm_unreachable("missing comparison operator"); 4566 case BO_LT: return Success(LHSOffset < RHSOffset, E); 4567 case BO_GT: return Success(LHSOffset > RHSOffset, E); 4568 case BO_LE: return Success(LHSOffset <= RHSOffset, E); 4569 case BO_GE: return Success(LHSOffset >= RHSOffset, E); 4570 case BO_EQ: return Success(LHSOffset == RHSOffset, E); 4571 case BO_NE: return Success(LHSOffset != RHSOffset, E); 4572 } 4573 } 4574 } 4575 4576 if (LHSTy->isMemberPointerType()) { 4577 assert(E->isEqualityOp() && "unexpected member pointer operation"); 4578 assert(RHSTy->isMemberPointerType() && "invalid comparison"); 4579 4580 MemberPtr LHSValue, RHSValue; 4581 4582 bool LHSOK = EvaluateMemberPointer(E->getLHS(), LHSValue, Info); 4583 if (!LHSOK && Info.keepEvaluatingAfterFailure()) 4584 return false; 4585 4586 if (!EvaluateMemberPointer(E->getRHS(), RHSValue, Info) || !LHSOK) 4587 return false; 4588 4589 // C++11 [expr.eq]p2: 4590 // If both operands are null, they compare equal. Otherwise if only one is 4591 // null, they compare unequal. 4592 if (!LHSValue.getDecl() || !RHSValue.getDecl()) { 4593 bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl(); 4594 return Success(E->getOpcode() == BO_EQ ? Equal : !Equal, E); 4595 } 4596 4597 // Otherwise if either is a pointer to a virtual member function, the 4598 // result is unspecified. 4599 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl())) 4600 if (MD->isVirtual()) 4601 CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD; 4602 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl())) 4603 if (MD->isVirtual()) 4604 CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD; 4605 4606 // Otherwise they compare equal if and only if they would refer to the 4607 // same member of the same most derived object or the same subobject if 4608 // they were dereferenced with a hypothetical object of the associated 4609 // class type. 4610 bool Equal = LHSValue == RHSValue; 4611 return Success(E->getOpcode() == BO_EQ ? Equal : !Equal, E); 4612 } 4613 4614 if (!LHSTy->isIntegralOrEnumerationType() || 4615 !RHSTy->isIntegralOrEnumerationType()) { 4616 // We can't continue from here for non-integral types. 4617 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 4618 } 4619 4620 // The LHS of a constant expr is always evaluated and needed. 4621 CCValue LHSVal; 4622 4623 bool LHSOK = EvaluateIntegerOrLValue(E->getLHS(), LHSVal, Info); 4624 if (!LHSOK && !Info.keepEvaluatingAfterFailure()) 4625 return false; 4626 4627 if (!Visit(E->getRHS()) || !LHSOK) 4628 return false; 4629 4630 CCValue &RHSVal = Result; 4631 4632 // Handle cases like (unsigned long)&a + 4. 4633 if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) { 4634 CharUnits AdditionalOffset = CharUnits::fromQuantity( 4635 RHSVal.getInt().getZExtValue()); 4636 if (E->getOpcode() == BO_Add) 4637 LHSVal.getLValueOffset() += AdditionalOffset; 4638 else 4639 LHSVal.getLValueOffset() -= AdditionalOffset; 4640 Result = LHSVal; 4641 return true; 4642 } 4643 4644 // Handle cases like 4 + (unsigned long)&a 4645 if (E->getOpcode() == BO_Add && 4646 RHSVal.isLValue() && LHSVal.isInt()) { 4647 RHSVal.getLValueOffset() += CharUnits::fromQuantity( 4648 LHSVal.getInt().getZExtValue()); 4649 // Note that RHSVal is Result. 4650 return true; 4651 } 4652 4653 if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) { 4654 // Handle (intptr_t)&&A - (intptr_t)&&B. 4655 if (!LHSVal.getLValueOffset().isZero() || 4656 !RHSVal.getLValueOffset().isZero()) 4657 return false; 4658 const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>(); 4659 const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>(); 4660 if (!LHSExpr || !RHSExpr) 4661 return false; 4662 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr); 4663 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr); 4664 if (!LHSAddrExpr || !RHSAddrExpr) 4665 return false; 4666 // Make sure both labels come from the same function. 4667 if (LHSAddrExpr->getLabel()->getDeclContext() != 4668 RHSAddrExpr->getLabel()->getDeclContext()) 4669 return false; 4670 Result = CCValue(LHSAddrExpr, RHSAddrExpr); 4671 return true; 4672 } 4673 4674 // All the following cases expect both operands to be an integer 4675 if (!LHSVal.isInt() || !RHSVal.isInt()) 4676 return Error(E); 4677 4678 APSInt &LHS = LHSVal.getInt(); 4679 APSInt &RHS = RHSVal.getInt(); 4680 4681 switch (E->getOpcode()) { 4682 default: 4683 return Error(E); 4684 case BO_Mul: 4685 return Success(CheckedIntArithmetic(Info, E, LHS, RHS, 4686 LHS.getBitWidth() * 2, 4687 std::multiplies<APSInt>()), E); 4688 case BO_Add: 4689 return Success(CheckedIntArithmetic(Info, E, LHS, RHS, 4690 LHS.getBitWidth() + 1, 4691 std::plus<APSInt>()), E); 4692 case BO_Sub: 4693 return Success(CheckedIntArithmetic(Info, E, LHS, RHS, 4694 LHS.getBitWidth() + 1, 4695 std::minus<APSInt>()), E); 4696 case BO_And: return Success(LHS & RHS, E); 4697 case BO_Xor: return Success(LHS ^ RHS, E); 4698 case BO_Or: return Success(LHS | RHS, E); 4699 case BO_Div: 4700 case BO_Rem: 4701 if (RHS == 0) 4702 return Error(E, diag::note_expr_divide_by_zero); 4703 // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. The latter is not 4704 // actually undefined behavior in C++11 due to a language defect. 4705 if (RHS.isNegative() && RHS.isAllOnesValue() && 4706 LHS.isSigned() && LHS.isMinSignedValue()) 4707 HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1), E->getType()); 4708 return Success(E->getOpcode() == BO_Rem ? LHS % RHS : LHS / RHS, E); 4709 case BO_Shl: { 4710 // During constant-folding, a negative shift is an opposite shift. Such a 4711 // shift is not a constant expression. 4712 if (RHS.isSigned() && RHS.isNegative()) { 4713 CCEDiag(E, diag::note_constexpr_negative_shift) << RHS; 4714 RHS = -RHS; 4715 goto shift_right; 4716 } 4717 4718 shift_left: 4719 // C++11 [expr.shift]p1: Shift width must be less than the bit width of the 4720 // shifted type. 4721 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1); 4722 if (SA != RHS) { 4723 CCEDiag(E, diag::note_constexpr_large_shift) 4724 << RHS << E->getType() << LHS.getBitWidth(); 4725 } else if (LHS.isSigned()) { 4726 // C++11 [expr.shift]p2: A signed left shift must have a non-negative 4727 // operand, and must not overflow the corresponding unsigned type. 4728 if (LHS.isNegative()) 4729 CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS; 4730 else if (LHS.countLeadingZeros() < SA) 4731 CCEDiag(E, diag::note_constexpr_lshift_discards); 4732 } 4733 4734 return Success(LHS << SA, E); 4735 } 4736 case BO_Shr: { 4737 // During constant-folding, a negative shift is an opposite shift. Such a 4738 // shift is not a constant expression. 4739 if (RHS.isSigned() && RHS.isNegative()) { 4740 CCEDiag(E, diag::note_constexpr_negative_shift) << RHS; 4741 RHS = -RHS; 4742 goto shift_left; 4743 } 4744 4745 shift_right: 4746 // C++11 [expr.shift]p1: Shift width must be less than the bit width of the 4747 // shifted type. 4748 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1); 4749 if (SA != RHS) 4750 CCEDiag(E, diag::note_constexpr_large_shift) 4751 << RHS << E->getType() << LHS.getBitWidth(); 4752 4753 return Success(LHS >> SA, E); 4754 } 4755 4756 case BO_LT: return Success(LHS < RHS, E); 4757 case BO_GT: return Success(LHS > RHS, E); 4758 case BO_LE: return Success(LHS <= RHS, E); 4759 case BO_GE: return Success(LHS >= RHS, E); 4760 case BO_EQ: return Success(LHS == RHS, E); 4761 case BO_NE: return Success(LHS != RHS, E); 4762 } 4763} 4764 4765CharUnits IntExprEvaluator::GetAlignOfType(QualType T) { 4766 // C++ [expr.sizeof]p2: "When applied to a reference or a reference type, 4767 // the result is the size of the referenced type." 4768 // C++ [expr.alignof]p3: "When alignof is applied to a reference type, the 4769 // result shall be the alignment of the referenced type." 4770 if (const ReferenceType *Ref = T->getAs<ReferenceType>()) 4771 T = Ref->getPointeeType(); 4772 4773 // __alignof is defined to return the preferred alignment. 4774 return Info.Ctx.toCharUnitsFromBits( 4775 Info.Ctx.getPreferredTypeAlign(T.getTypePtr())); 4776} 4777 4778CharUnits IntExprEvaluator::GetAlignOfExpr(const Expr *E) { 4779 E = E->IgnoreParens(); 4780 4781 // alignof decl is always accepted, even if it doesn't make sense: we default 4782 // to 1 in those cases. 4783 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 4784 return Info.Ctx.getDeclAlign(DRE->getDecl(), 4785 /*RefAsPointee*/true); 4786 4787 if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) 4788 return Info.Ctx.getDeclAlign(ME->getMemberDecl(), 4789 /*RefAsPointee*/true); 4790 4791 return GetAlignOfType(E->getType()); 4792} 4793 4794 4795/// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with 4796/// a result as the expression's type. 4797bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr( 4798 const UnaryExprOrTypeTraitExpr *E) { 4799 switch(E->getKind()) { 4800 case UETT_AlignOf: { 4801 if (E->isArgumentType()) 4802 return Success(GetAlignOfType(E->getArgumentType()), E); 4803 else 4804 return Success(GetAlignOfExpr(E->getArgumentExpr()), E); 4805 } 4806 4807 case UETT_VecStep: { 4808 QualType Ty = E->getTypeOfArgument(); 4809 4810 if (Ty->isVectorType()) { 4811 unsigned n = Ty->getAs<VectorType>()->getNumElements(); 4812 4813 // The vec_step built-in functions that take a 3-component 4814 // vector return 4. (OpenCL 1.1 spec 6.11.12) 4815 if (n == 3) 4816 n = 4; 4817 4818 return Success(n, E); 4819 } else 4820 return Success(1, E); 4821 } 4822 4823 case UETT_SizeOf: { 4824 QualType SrcTy = E->getTypeOfArgument(); 4825 // C++ [expr.sizeof]p2: "When applied to a reference or a reference type, 4826 // the result is the size of the referenced type." 4827 // C++ [expr.alignof]p3: "When alignof is applied to a reference type, the 4828 // result shall be the alignment of the referenced type." 4829 if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>()) 4830 SrcTy = Ref->getPointeeType(); 4831 4832 CharUnits Sizeof; 4833 if (!HandleSizeof(Info, SrcTy, Sizeof)) 4834 return false; 4835 return Success(Sizeof, E); 4836 } 4837 } 4838 4839 llvm_unreachable("unknown expr/type trait"); 4840} 4841 4842bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) { 4843 CharUnits Result; 4844 unsigned n = OOE->getNumComponents(); 4845 if (n == 0) 4846 return Error(OOE); 4847 QualType CurrentType = OOE->getTypeSourceInfo()->getType(); 4848 for (unsigned i = 0; i != n; ++i) { 4849 OffsetOfExpr::OffsetOfNode ON = OOE->getComponent(i); 4850 switch (ON.getKind()) { 4851 case OffsetOfExpr::OffsetOfNode::Array: { 4852 const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex()); 4853 APSInt IdxResult; 4854 if (!EvaluateInteger(Idx, IdxResult, Info)) 4855 return false; 4856 const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType); 4857 if (!AT) 4858 return Error(OOE); 4859 CurrentType = AT->getElementType(); 4860 CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType); 4861 Result += IdxResult.getSExtValue() * ElementSize; 4862 break; 4863 } 4864 4865 case OffsetOfExpr::OffsetOfNode::Field: { 4866 FieldDecl *MemberDecl = ON.getField(); 4867 const RecordType *RT = CurrentType->getAs<RecordType>(); 4868 if (!RT) 4869 return Error(OOE); 4870 RecordDecl *RD = RT->getDecl(); 4871 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD); 4872 unsigned i = MemberDecl->getFieldIndex(); 4873 assert(i < RL.getFieldCount() && "offsetof field in wrong type"); 4874 Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i)); 4875 CurrentType = MemberDecl->getType().getNonReferenceType(); 4876 break; 4877 } 4878 4879 case OffsetOfExpr::OffsetOfNode::Identifier: 4880 llvm_unreachable("dependent __builtin_offsetof"); 4881 4882 case OffsetOfExpr::OffsetOfNode::Base: { 4883 CXXBaseSpecifier *BaseSpec = ON.getBase(); 4884 if (BaseSpec->isVirtual()) 4885 return Error(OOE); 4886 4887 // Find the layout of the class whose base we are looking into. 4888 const RecordType *RT = CurrentType->getAs<RecordType>(); 4889 if (!RT) 4890 return Error(OOE); 4891 RecordDecl *RD = RT->getDecl(); 4892 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD); 4893 4894 // Find the base class itself. 4895 CurrentType = BaseSpec->getType(); 4896 const RecordType *BaseRT = CurrentType->getAs<RecordType>(); 4897 if (!BaseRT) 4898 return Error(OOE); 4899 4900 // Add the offset to the base. 4901 Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl())); 4902 break; 4903 } 4904 } 4905 } 4906 return Success(Result, OOE); 4907} 4908 4909bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { 4910 switch (E->getOpcode()) { 4911 default: 4912 // Address, indirect, pre/post inc/dec, etc are not valid constant exprs. 4913 // See C99 6.6p3. 4914 return Error(E); 4915 case UO_Extension: 4916 // FIXME: Should extension allow i-c-e extension expressions in its scope? 4917 // If so, we could clear the diagnostic ID. 4918 return Visit(E->getSubExpr()); 4919 case UO_Plus: 4920 // The result is just the value. 4921 return Visit(E->getSubExpr()); 4922 case UO_Minus: { 4923 if (!Visit(E->getSubExpr())) 4924 return false; 4925 if (!Result.isInt()) return Error(E); 4926 const APSInt &Value = Result.getInt(); 4927 if (Value.isSigned() && Value.isMinSignedValue()) 4928 HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1), 4929 E->getType()); 4930 return Success(-Value, E); 4931 } 4932 case UO_Not: { 4933 if (!Visit(E->getSubExpr())) 4934 return false; 4935 if (!Result.isInt()) return Error(E); 4936 return Success(~Result.getInt(), E); 4937 } 4938 case UO_LNot: { 4939 bool bres; 4940 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info)) 4941 return false; 4942 return Success(!bres, E); 4943 } 4944 } 4945} 4946 4947/// HandleCast - This is used to evaluate implicit or explicit casts where the 4948/// result type is integer. 4949bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) { 4950 const Expr *SubExpr = E->getSubExpr(); 4951 QualType DestType = E->getType(); 4952 QualType SrcType = SubExpr->getType(); 4953 4954 switch (E->getCastKind()) { 4955 case CK_BaseToDerived: 4956 case CK_DerivedToBase: 4957 case CK_UncheckedDerivedToBase: 4958 case CK_Dynamic: 4959 case CK_ToUnion: 4960 case CK_ArrayToPointerDecay: 4961 case CK_FunctionToPointerDecay: 4962 case CK_NullToPointer: 4963 case CK_NullToMemberPointer: 4964 case CK_BaseToDerivedMemberPointer: 4965 case CK_DerivedToBaseMemberPointer: 4966 case CK_ConstructorConversion: 4967 case CK_IntegralToPointer: 4968 case CK_ToVoid: 4969 case CK_VectorSplat: 4970 case CK_IntegralToFloating: 4971 case CK_FloatingCast: 4972 case CK_CPointerToObjCPointerCast: 4973 case CK_BlockPointerToObjCPointerCast: 4974 case CK_AnyPointerToBlockPointerCast: 4975 case CK_ObjCObjectLValueCast: 4976 case CK_FloatingRealToComplex: 4977 case CK_FloatingComplexToReal: 4978 case CK_FloatingComplexCast: 4979 case CK_FloatingComplexToIntegralComplex: 4980 case CK_IntegralRealToComplex: 4981 case CK_IntegralComplexCast: 4982 case CK_IntegralComplexToFloatingComplex: 4983 llvm_unreachable("invalid cast kind for integral value"); 4984 4985 case CK_BitCast: 4986 case CK_Dependent: 4987 case CK_LValueBitCast: 4988 case CK_ARCProduceObject: 4989 case CK_ARCConsumeObject: 4990 case CK_ARCReclaimReturnedObject: 4991 case CK_ARCExtendBlockObject: 4992 return Error(E); 4993 4994 case CK_UserDefinedConversion: 4995 case CK_LValueToRValue: 4996 case CK_AtomicToNonAtomic: 4997 case CK_NonAtomicToAtomic: 4998 case CK_NoOp: 4999 return ExprEvaluatorBaseTy::VisitCastExpr(E); 5000 5001 case CK_MemberPointerToBoolean: 5002 case CK_PointerToBoolean: 5003 case CK_IntegralToBoolean: 5004 case CK_FloatingToBoolean: 5005 case CK_FloatingComplexToBoolean: 5006 case CK_IntegralComplexToBoolean: { 5007 bool BoolResult; 5008 if (!EvaluateAsBooleanCondition(SubExpr, BoolResult, Info)) 5009 return false; 5010 return Success(BoolResult, E); 5011 } 5012 5013 case CK_IntegralCast: { 5014 if (!Visit(SubExpr)) 5015 return false; 5016 5017 if (!Result.isInt()) { 5018 // Allow casts of address-of-label differences if they are no-ops 5019 // or narrowing. (The narrowing case isn't actually guaranteed to 5020 // be constant-evaluatable except in some narrow cases which are hard 5021 // to detect here. We let it through on the assumption the user knows 5022 // what they are doing.) 5023 if (Result.isAddrLabelDiff()) 5024 return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType); 5025 // Only allow casts of lvalues if they are lossless. 5026 return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType); 5027 } 5028 5029 return Success(HandleIntToIntCast(Info, E, DestType, SrcType, 5030 Result.getInt()), E); 5031 } 5032 5033 case CK_PointerToIntegral: { 5034 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2; 5035 5036 LValue LV; 5037 if (!EvaluatePointer(SubExpr, LV, Info)) 5038 return false; 5039 5040 if (LV.getLValueBase()) { 5041 // Only allow based lvalue casts if they are lossless. 5042 // FIXME: Allow a larger integer size than the pointer size, and allow 5043 // narrowing back down to pointer width in subsequent integral casts. 5044 // FIXME: Check integer type's active bits, not its type size. 5045 if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType)) 5046 return Error(E); 5047 5048 LV.Designator.setInvalid(); 5049 LV.moveInto(Result); 5050 return true; 5051 } 5052 5053 APSInt AsInt = Info.Ctx.MakeIntValue(LV.getLValueOffset().getQuantity(), 5054 SrcType); 5055 return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E); 5056 } 5057 5058 case CK_IntegralComplexToReal: { 5059 ComplexValue C; 5060 if (!EvaluateComplex(SubExpr, C, Info)) 5061 return false; 5062 return Success(C.getComplexIntReal(), E); 5063 } 5064 5065 case CK_FloatingToIntegral: { 5066 APFloat F(0.0); 5067 if (!EvaluateFloat(SubExpr, F, Info)) 5068 return false; 5069 5070 APSInt Value; 5071 if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value)) 5072 return false; 5073 return Success(Value, E); 5074 } 5075 } 5076 5077 llvm_unreachable("unknown cast resulting in integral value"); 5078} 5079 5080bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) { 5081 if (E->getSubExpr()->getType()->isAnyComplexType()) { 5082 ComplexValue LV; 5083 if (!EvaluateComplex(E->getSubExpr(), LV, Info)) 5084 return false; 5085 if (!LV.isComplexInt()) 5086 return Error(E); 5087 return Success(LV.getComplexIntReal(), E); 5088 } 5089 5090 return Visit(E->getSubExpr()); 5091} 5092 5093bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { 5094 if (E->getSubExpr()->getType()->isComplexIntegerType()) { 5095 ComplexValue LV; 5096 if (!EvaluateComplex(E->getSubExpr(), LV, Info)) 5097 return false; 5098 if (!LV.isComplexInt()) 5099 return Error(E); 5100 return Success(LV.getComplexIntImag(), E); 5101 } 5102 5103 VisitIgnoredValue(E->getSubExpr()); 5104 return Success(0, E); 5105} 5106 5107bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) { 5108 return Success(E->getPackLength(), E); 5109} 5110 5111bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) { 5112 return Success(E->getValue(), E); 5113} 5114 5115//===----------------------------------------------------------------------===// 5116// Float Evaluation 5117//===----------------------------------------------------------------------===// 5118 5119namespace { 5120class FloatExprEvaluator 5121 : public ExprEvaluatorBase<FloatExprEvaluator, bool> { 5122 APFloat &Result; 5123public: 5124 FloatExprEvaluator(EvalInfo &info, APFloat &result) 5125 : ExprEvaluatorBaseTy(info), Result(result) {} 5126 5127 bool Success(const CCValue &V, const Expr *e) { 5128 Result = V.getFloat(); 5129 return true; 5130 } 5131 5132 bool ZeroInitialization(const Expr *E) { 5133 Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType())); 5134 return true; 5135 } 5136 5137 bool VisitCallExpr(const CallExpr *E); 5138 5139 bool VisitUnaryOperator(const UnaryOperator *E); 5140 bool VisitBinaryOperator(const BinaryOperator *E); 5141 bool VisitFloatingLiteral(const FloatingLiteral *E); 5142 bool VisitCastExpr(const CastExpr *E); 5143 5144 bool VisitUnaryReal(const UnaryOperator *E); 5145 bool VisitUnaryImag(const UnaryOperator *E); 5146 5147 // FIXME: Missing: array subscript of vector, member of vector 5148}; 5149} // end anonymous namespace 5150 5151static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) { 5152 assert(E->isRValue() && E->getType()->isRealFloatingType()); 5153 return FloatExprEvaluator(Info, Result).Visit(E); 5154} 5155 5156static bool TryEvaluateBuiltinNaN(const ASTContext &Context, 5157 QualType ResultTy, 5158 const Expr *Arg, 5159 bool SNaN, 5160 llvm::APFloat &Result) { 5161 const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts()); 5162 if (!S) return false; 5163 5164 const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy); 5165 5166 llvm::APInt fill; 5167 5168 // Treat empty strings as if they were zero. 5169 if (S->getString().empty()) 5170 fill = llvm::APInt(32, 0); 5171 else if (S->getString().getAsInteger(0, fill)) 5172 return false; 5173 5174 if (SNaN) 5175 Result = llvm::APFloat::getSNaN(Sem, false, &fill); 5176 else 5177 Result = llvm::APFloat::getQNaN(Sem, false, &fill); 5178 return true; 5179} 5180 5181bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) { 5182 switch (E->isBuiltinCall()) { 5183 default: 5184 return ExprEvaluatorBaseTy::VisitCallExpr(E); 5185 5186 case Builtin::BI__builtin_huge_val: 5187 case Builtin::BI__builtin_huge_valf: 5188 case Builtin::BI__builtin_huge_vall: 5189 case Builtin::BI__builtin_inf: 5190 case Builtin::BI__builtin_inff: 5191 case Builtin::BI__builtin_infl: { 5192 const llvm::fltSemantics &Sem = 5193 Info.Ctx.getFloatTypeSemantics(E->getType()); 5194 Result = llvm::APFloat::getInf(Sem); 5195 return true; 5196 } 5197 5198 case Builtin::BI__builtin_nans: 5199 case Builtin::BI__builtin_nansf: 5200 case Builtin::BI__builtin_nansl: 5201 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0), 5202 true, Result)) 5203 return Error(E); 5204 return true; 5205 5206 case Builtin::BI__builtin_nan: 5207 case Builtin::BI__builtin_nanf: 5208 case Builtin::BI__builtin_nanl: 5209 // If this is __builtin_nan() turn this into a nan, otherwise we 5210 // can't constant fold it. 5211 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0), 5212 false, Result)) 5213 return Error(E); 5214 return true; 5215 5216 case Builtin::BI__builtin_fabs: 5217 case Builtin::BI__builtin_fabsf: 5218 case Builtin::BI__builtin_fabsl: 5219 if (!EvaluateFloat(E->getArg(0), Result, Info)) 5220 return false; 5221 5222 if (Result.isNegative()) 5223 Result.changeSign(); 5224 return true; 5225 5226 case Builtin::BI__builtin_copysign: 5227 case Builtin::BI__builtin_copysignf: 5228 case Builtin::BI__builtin_copysignl: { 5229 APFloat RHS(0.); 5230 if (!EvaluateFloat(E->getArg(0), Result, Info) || 5231 !EvaluateFloat(E->getArg(1), RHS, Info)) 5232 return false; 5233 Result.copySign(RHS); 5234 return true; 5235 } 5236 } 5237} 5238 5239bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) { 5240 if (E->getSubExpr()->getType()->isAnyComplexType()) { 5241 ComplexValue CV; 5242 if (!EvaluateComplex(E->getSubExpr(), CV, Info)) 5243 return false; 5244 Result = CV.FloatReal; 5245 return true; 5246 } 5247 5248 return Visit(E->getSubExpr()); 5249} 5250 5251bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { 5252 if (E->getSubExpr()->getType()->isAnyComplexType()) { 5253 ComplexValue CV; 5254 if (!EvaluateComplex(E->getSubExpr(), CV, Info)) 5255 return false; 5256 Result = CV.FloatImag; 5257 return true; 5258 } 5259 5260 VisitIgnoredValue(E->getSubExpr()); 5261 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType()); 5262 Result = llvm::APFloat::getZero(Sem); 5263 return true; 5264} 5265 5266bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { 5267 switch (E->getOpcode()) { 5268 default: return Error(E); 5269 case UO_Plus: 5270 return EvaluateFloat(E->getSubExpr(), Result, Info); 5271 case UO_Minus: 5272 if (!EvaluateFloat(E->getSubExpr(), Result, Info)) 5273 return false; 5274 Result.changeSign(); 5275 return true; 5276 } 5277} 5278 5279bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 5280 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma) 5281 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 5282 5283 APFloat RHS(0.0); 5284 bool LHSOK = EvaluateFloat(E->getLHS(), Result, Info); 5285 if (!LHSOK && !Info.keepEvaluatingAfterFailure()) 5286 return false; 5287 if (!EvaluateFloat(E->getRHS(), RHS, Info) || !LHSOK) 5288 return false; 5289 5290 switch (E->getOpcode()) { 5291 default: return Error(E); 5292 case BO_Mul: 5293 Result.multiply(RHS, APFloat::rmNearestTiesToEven); 5294 break; 5295 case BO_Add: 5296 Result.add(RHS, APFloat::rmNearestTiesToEven); 5297 break; 5298 case BO_Sub: 5299 Result.subtract(RHS, APFloat::rmNearestTiesToEven); 5300 break; 5301 case BO_Div: 5302 Result.divide(RHS, APFloat::rmNearestTiesToEven); 5303 break; 5304 } 5305 5306 if (Result.isInfinity() || Result.isNaN()) 5307 CCEDiag(E, diag::note_constexpr_float_arithmetic) << Result.isNaN(); 5308 return true; 5309} 5310 5311bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) { 5312 Result = E->getValue(); 5313 return true; 5314} 5315 5316bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) { 5317 const Expr* SubExpr = E->getSubExpr(); 5318 5319 switch (E->getCastKind()) { 5320 default: 5321 return ExprEvaluatorBaseTy::VisitCastExpr(E); 5322 5323 case CK_IntegralToFloating: { 5324 APSInt IntResult; 5325 return EvaluateInteger(SubExpr, IntResult, Info) && 5326 HandleIntToFloatCast(Info, E, SubExpr->getType(), IntResult, 5327 E->getType(), Result); 5328 } 5329 5330 case CK_FloatingCast: { 5331 if (!Visit(SubExpr)) 5332 return false; 5333 return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(), 5334 Result); 5335 } 5336 5337 case CK_FloatingComplexToReal: { 5338 ComplexValue V; 5339 if (!EvaluateComplex(SubExpr, V, Info)) 5340 return false; 5341 Result = V.getComplexFloatReal(); 5342 return true; 5343 } 5344 } 5345} 5346 5347//===----------------------------------------------------------------------===// 5348// Complex Evaluation (for float and integer) 5349//===----------------------------------------------------------------------===// 5350 5351namespace { 5352class ComplexExprEvaluator 5353 : public ExprEvaluatorBase<ComplexExprEvaluator, bool> { 5354 ComplexValue &Result; 5355 5356public: 5357 ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result) 5358 : ExprEvaluatorBaseTy(info), Result(Result) {} 5359 5360 bool Success(const CCValue &V, const Expr *e) { 5361 Result.setFrom(V); 5362 return true; 5363 } 5364 5365 bool ZeroInitialization(const Expr *E); 5366 5367 //===--------------------------------------------------------------------===// 5368 // Visitor Methods 5369 //===--------------------------------------------------------------------===// 5370 5371 bool VisitImaginaryLiteral(const ImaginaryLiteral *E); 5372 bool VisitCastExpr(const CastExpr *E); 5373 bool VisitBinaryOperator(const BinaryOperator *E); 5374 bool VisitUnaryOperator(const UnaryOperator *E); 5375 bool VisitInitListExpr(const InitListExpr *E); 5376}; 5377} // end anonymous namespace 5378 5379static bool EvaluateComplex(const Expr *E, ComplexValue &Result, 5380 EvalInfo &Info) { 5381 assert(E->isRValue() && E->getType()->isAnyComplexType()); 5382 return ComplexExprEvaluator(Info, Result).Visit(E); 5383} 5384 5385bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) { 5386 QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType(); 5387 if (ElemTy->isRealFloatingType()) { 5388 Result.makeComplexFloat(); 5389 APFloat Zero = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(ElemTy)); 5390 Result.FloatReal = Zero; 5391 Result.FloatImag = Zero; 5392 } else { 5393 Result.makeComplexInt(); 5394 APSInt Zero = Info.Ctx.MakeIntValue(0, ElemTy); 5395 Result.IntReal = Zero; 5396 Result.IntImag = Zero; 5397 } 5398 return true; 5399} 5400 5401bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) { 5402 const Expr* SubExpr = E->getSubExpr(); 5403 5404 if (SubExpr->getType()->isRealFloatingType()) { 5405 Result.makeComplexFloat(); 5406 APFloat &Imag = Result.FloatImag; 5407 if (!EvaluateFloat(SubExpr, Imag, Info)) 5408 return false; 5409 5410 Result.FloatReal = APFloat(Imag.getSemantics()); 5411 return true; 5412 } else { 5413 assert(SubExpr->getType()->isIntegerType() && 5414 "Unexpected imaginary literal."); 5415 5416 Result.makeComplexInt(); 5417 APSInt &Imag = Result.IntImag; 5418 if (!EvaluateInteger(SubExpr, Imag, Info)) 5419 return false; 5420 5421 Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned()); 5422 return true; 5423 } 5424} 5425 5426bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) { 5427 5428 switch (E->getCastKind()) { 5429 case CK_BitCast: 5430 case CK_BaseToDerived: 5431 case CK_DerivedToBase: 5432 case CK_UncheckedDerivedToBase: 5433 case CK_Dynamic: 5434 case CK_ToUnion: 5435 case CK_ArrayToPointerDecay: 5436 case CK_FunctionToPointerDecay: 5437 case CK_NullToPointer: 5438 case CK_NullToMemberPointer: 5439 case CK_BaseToDerivedMemberPointer: 5440 case CK_DerivedToBaseMemberPointer: 5441 case CK_MemberPointerToBoolean: 5442 case CK_ConstructorConversion: 5443 case CK_IntegralToPointer: 5444 case CK_PointerToIntegral: 5445 case CK_PointerToBoolean: 5446 case CK_ToVoid: 5447 case CK_VectorSplat: 5448 case CK_IntegralCast: 5449 case CK_IntegralToBoolean: 5450 case CK_IntegralToFloating: 5451 case CK_FloatingToIntegral: 5452 case CK_FloatingToBoolean: 5453 case CK_FloatingCast: 5454 case CK_CPointerToObjCPointerCast: 5455 case CK_BlockPointerToObjCPointerCast: 5456 case CK_AnyPointerToBlockPointerCast: 5457 case CK_ObjCObjectLValueCast: 5458 case CK_FloatingComplexToReal: 5459 case CK_FloatingComplexToBoolean: 5460 case CK_IntegralComplexToReal: 5461 case CK_IntegralComplexToBoolean: 5462 case CK_ARCProduceObject: 5463 case CK_ARCConsumeObject: 5464 case CK_ARCReclaimReturnedObject: 5465 case CK_ARCExtendBlockObject: 5466 llvm_unreachable("invalid cast kind for complex value"); 5467 5468 case CK_LValueToRValue: 5469 case CK_AtomicToNonAtomic: 5470 case CK_NonAtomicToAtomic: 5471 case CK_NoOp: 5472 return ExprEvaluatorBaseTy::VisitCastExpr(E); 5473 5474 case CK_Dependent: 5475 case CK_LValueBitCast: 5476 case CK_UserDefinedConversion: 5477 return Error(E); 5478 5479 case CK_FloatingRealToComplex: { 5480 APFloat &Real = Result.FloatReal; 5481 if (!EvaluateFloat(E->getSubExpr(), Real, Info)) 5482 return false; 5483 5484 Result.makeComplexFloat(); 5485 Result.FloatImag = APFloat(Real.getSemantics()); 5486 return true; 5487 } 5488 5489 case CK_FloatingComplexCast: { 5490 if (!Visit(E->getSubExpr())) 5491 return false; 5492 5493 QualType To = E->getType()->getAs<ComplexType>()->getElementType(); 5494 QualType From 5495 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType(); 5496 5497 return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) && 5498 HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag); 5499 } 5500 5501 case CK_FloatingComplexToIntegralComplex: { 5502 if (!Visit(E->getSubExpr())) 5503 return false; 5504 5505 QualType To = E->getType()->getAs<ComplexType>()->getElementType(); 5506 QualType From 5507 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType(); 5508 Result.makeComplexInt(); 5509 return HandleFloatToIntCast(Info, E, From, Result.FloatReal, 5510 To, Result.IntReal) && 5511 HandleFloatToIntCast(Info, E, From, Result.FloatImag, 5512 To, Result.IntImag); 5513 } 5514 5515 case CK_IntegralRealToComplex: { 5516 APSInt &Real = Result.IntReal; 5517 if (!EvaluateInteger(E->getSubExpr(), Real, Info)) 5518 return false; 5519 5520 Result.makeComplexInt(); 5521 Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned()); 5522 return true; 5523 } 5524 5525 case CK_IntegralComplexCast: { 5526 if (!Visit(E->getSubExpr())) 5527 return false; 5528 5529 QualType To = E->getType()->getAs<ComplexType>()->getElementType(); 5530 QualType From 5531 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType(); 5532 5533 Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal); 5534 Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag); 5535 return true; 5536 } 5537 5538 case CK_IntegralComplexToFloatingComplex: { 5539 if (!Visit(E->getSubExpr())) 5540 return false; 5541 5542 QualType To = E->getType()->getAs<ComplexType>()->getElementType(); 5543 QualType From 5544 = E->getSubExpr()->getType()->getAs<ComplexType>()->getElementType(); 5545 Result.makeComplexFloat(); 5546 return HandleIntToFloatCast(Info, E, From, Result.IntReal, 5547 To, Result.FloatReal) && 5548 HandleIntToFloatCast(Info, E, From, Result.IntImag, 5549 To, Result.FloatImag); 5550 } 5551 } 5552 5553 llvm_unreachable("unknown cast resulting in complex value"); 5554} 5555 5556bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 5557 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma) 5558 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 5559 5560 bool LHSOK = Visit(E->getLHS()); 5561 if (!LHSOK && !Info.keepEvaluatingAfterFailure()) 5562 return false; 5563 5564 ComplexValue RHS; 5565 if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK) 5566 return false; 5567 5568 assert(Result.isComplexFloat() == RHS.isComplexFloat() && 5569 "Invalid operands to binary operator."); 5570 switch (E->getOpcode()) { 5571 default: return Error(E); 5572 case BO_Add: 5573 if (Result.isComplexFloat()) { 5574 Result.getComplexFloatReal().add(RHS.getComplexFloatReal(), 5575 APFloat::rmNearestTiesToEven); 5576 Result.getComplexFloatImag().add(RHS.getComplexFloatImag(), 5577 APFloat::rmNearestTiesToEven); 5578 } else { 5579 Result.getComplexIntReal() += RHS.getComplexIntReal(); 5580 Result.getComplexIntImag() += RHS.getComplexIntImag(); 5581 } 5582 break; 5583 case BO_Sub: 5584 if (Result.isComplexFloat()) { 5585 Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(), 5586 APFloat::rmNearestTiesToEven); 5587 Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(), 5588 APFloat::rmNearestTiesToEven); 5589 } else { 5590 Result.getComplexIntReal() -= RHS.getComplexIntReal(); 5591 Result.getComplexIntImag() -= RHS.getComplexIntImag(); 5592 } 5593 break; 5594 case BO_Mul: 5595 if (Result.isComplexFloat()) { 5596 ComplexValue LHS = Result; 5597 APFloat &LHS_r = LHS.getComplexFloatReal(); 5598 APFloat &LHS_i = LHS.getComplexFloatImag(); 5599 APFloat &RHS_r = RHS.getComplexFloatReal(); 5600 APFloat &RHS_i = RHS.getComplexFloatImag(); 5601 5602 APFloat Tmp = LHS_r; 5603 Tmp.multiply(RHS_r, APFloat::rmNearestTiesToEven); 5604 Result.getComplexFloatReal() = Tmp; 5605 Tmp = LHS_i; 5606 Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven); 5607 Result.getComplexFloatReal().subtract(Tmp, APFloat::rmNearestTiesToEven); 5608 5609 Tmp = LHS_r; 5610 Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven); 5611 Result.getComplexFloatImag() = Tmp; 5612 Tmp = LHS_i; 5613 Tmp.multiply(RHS_r, APFloat::rmNearestTiesToEven); 5614 Result.getComplexFloatImag().add(Tmp, APFloat::rmNearestTiesToEven); 5615 } else { 5616 ComplexValue LHS = Result; 5617 Result.getComplexIntReal() = 5618 (LHS.getComplexIntReal() * RHS.getComplexIntReal() - 5619 LHS.getComplexIntImag() * RHS.getComplexIntImag()); 5620 Result.getComplexIntImag() = 5621 (LHS.getComplexIntReal() * RHS.getComplexIntImag() + 5622 LHS.getComplexIntImag() * RHS.getComplexIntReal()); 5623 } 5624 break; 5625 case BO_Div: 5626 if (Result.isComplexFloat()) { 5627 ComplexValue LHS = Result; 5628 APFloat &LHS_r = LHS.getComplexFloatReal(); 5629 APFloat &LHS_i = LHS.getComplexFloatImag(); 5630 APFloat &RHS_r = RHS.getComplexFloatReal(); 5631 APFloat &RHS_i = RHS.getComplexFloatImag(); 5632 APFloat &Res_r = Result.getComplexFloatReal(); 5633 APFloat &Res_i = Result.getComplexFloatImag(); 5634 5635 APFloat Den = RHS_r; 5636 Den.multiply(RHS_r, APFloat::rmNearestTiesToEven); 5637 APFloat Tmp = RHS_i; 5638 Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven); 5639 Den.add(Tmp, APFloat::rmNearestTiesToEven); 5640 5641 Res_r = LHS_r; 5642 Res_r.multiply(RHS_r, APFloat::rmNearestTiesToEven); 5643 Tmp = LHS_i; 5644 Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven); 5645 Res_r.add(Tmp, APFloat::rmNearestTiesToEven); 5646 Res_r.divide(Den, APFloat::rmNearestTiesToEven); 5647 5648 Res_i = LHS_i; 5649 Res_i.multiply(RHS_r, APFloat::rmNearestTiesToEven); 5650 Tmp = LHS_r; 5651 Tmp.multiply(RHS_i, APFloat::rmNearestTiesToEven); 5652 Res_i.subtract(Tmp, APFloat::rmNearestTiesToEven); 5653 Res_i.divide(Den, APFloat::rmNearestTiesToEven); 5654 } else { 5655 if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0) 5656 return Error(E, diag::note_expr_divide_by_zero); 5657 5658 ComplexValue LHS = Result; 5659 APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() + 5660 RHS.getComplexIntImag() * RHS.getComplexIntImag(); 5661 Result.getComplexIntReal() = 5662 (LHS.getComplexIntReal() * RHS.getComplexIntReal() + 5663 LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den; 5664 Result.getComplexIntImag() = 5665 (LHS.getComplexIntImag() * RHS.getComplexIntReal() - 5666 LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den; 5667 } 5668 break; 5669 } 5670 5671 return true; 5672} 5673 5674bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { 5675 // Get the operand value into 'Result'. 5676 if (!Visit(E->getSubExpr())) 5677 return false; 5678 5679 switch (E->getOpcode()) { 5680 default: 5681 return Error(E); 5682 case UO_Extension: 5683 return true; 5684 case UO_Plus: 5685 // The result is always just the subexpr. 5686 return true; 5687 case UO_Minus: 5688 if (Result.isComplexFloat()) { 5689 Result.getComplexFloatReal().changeSign(); 5690 Result.getComplexFloatImag().changeSign(); 5691 } 5692 else { 5693 Result.getComplexIntReal() = -Result.getComplexIntReal(); 5694 Result.getComplexIntImag() = -Result.getComplexIntImag(); 5695 } 5696 return true; 5697 case UO_Not: 5698 if (Result.isComplexFloat()) 5699 Result.getComplexFloatImag().changeSign(); 5700 else 5701 Result.getComplexIntImag() = -Result.getComplexIntImag(); 5702 return true; 5703 } 5704} 5705 5706bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) { 5707 if (E->getNumInits() == 2) { 5708 if (E->getType()->isComplexType()) { 5709 Result.makeComplexFloat(); 5710 if (!EvaluateFloat(E->getInit(0), Result.FloatReal, Info)) 5711 return false; 5712 if (!EvaluateFloat(E->getInit(1), Result.FloatImag, Info)) 5713 return false; 5714 } else { 5715 Result.makeComplexInt(); 5716 if (!EvaluateInteger(E->getInit(0), Result.IntReal, Info)) 5717 return false; 5718 if (!EvaluateInteger(E->getInit(1), Result.IntImag, Info)) 5719 return false; 5720 } 5721 return true; 5722 } 5723 return ExprEvaluatorBaseTy::VisitInitListExpr(E); 5724} 5725 5726//===----------------------------------------------------------------------===// 5727// Void expression evaluation, primarily for a cast to void on the LHS of a 5728// comma operator 5729//===----------------------------------------------------------------------===// 5730 5731namespace { 5732class VoidExprEvaluator 5733 : public ExprEvaluatorBase<VoidExprEvaluator, bool> { 5734public: 5735 VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {} 5736 5737 bool Success(const CCValue &V, const Expr *e) { return true; } 5738 5739 bool VisitCastExpr(const CastExpr *E) { 5740 switch (E->getCastKind()) { 5741 default: 5742 return ExprEvaluatorBaseTy::VisitCastExpr(E); 5743 case CK_ToVoid: 5744 VisitIgnoredValue(E->getSubExpr()); 5745 return true; 5746 } 5747 } 5748}; 5749} // end anonymous namespace 5750 5751static bool EvaluateVoid(const Expr *E, EvalInfo &Info) { 5752 assert(E->isRValue() && E->getType()->isVoidType()); 5753 return VoidExprEvaluator(Info).Visit(E); 5754} 5755 5756//===----------------------------------------------------------------------===// 5757// Top level Expr::EvaluateAsRValue method. 5758//===----------------------------------------------------------------------===// 5759 5760static bool Evaluate(CCValue &Result, EvalInfo &Info, const Expr *E) { 5761 // In C, function designators are not lvalues, but we evaluate them as if they 5762 // are. 5763 if (E->isGLValue() || E->getType()->isFunctionType()) { 5764 LValue LV; 5765 if (!EvaluateLValue(E, LV, Info)) 5766 return false; 5767 LV.moveInto(Result); 5768 } else if (E->getType()->isVectorType()) { 5769 if (!EvaluateVector(E, Result, Info)) 5770 return false; 5771 } else if (E->getType()->isIntegralOrEnumerationType()) { 5772 if (!IntExprEvaluator(Info, Result).Visit(E)) 5773 return false; 5774 } else if (E->getType()->hasPointerRepresentation()) { 5775 LValue LV; 5776 if (!EvaluatePointer(E, LV, Info)) 5777 return false; 5778 LV.moveInto(Result); 5779 } else if (E->getType()->isRealFloatingType()) { 5780 llvm::APFloat F(0.0); 5781 if (!EvaluateFloat(E, F, Info)) 5782 return false; 5783 Result = CCValue(F); 5784 } else if (E->getType()->isAnyComplexType()) { 5785 ComplexValue C; 5786 if (!EvaluateComplex(E, C, Info)) 5787 return false; 5788 C.moveInto(Result); 5789 } else if (E->getType()->isMemberPointerType()) { 5790 MemberPtr P; 5791 if (!EvaluateMemberPointer(E, P, Info)) 5792 return false; 5793 P.moveInto(Result); 5794 return true; 5795 } else if (E->getType()->isArrayType()) { 5796 LValue LV; 5797 LV.set(E, Info.CurrentCall); 5798 if (!EvaluateArray(E, LV, Info.CurrentCall->Temporaries[E], Info)) 5799 return false; 5800 Result = Info.CurrentCall->Temporaries[E]; 5801 } else if (E->getType()->isRecordType()) { 5802 LValue LV; 5803 LV.set(E, Info.CurrentCall); 5804 if (!EvaluateRecord(E, LV, Info.CurrentCall->Temporaries[E], Info)) 5805 return false; 5806 Result = Info.CurrentCall->Temporaries[E]; 5807 } else if (E->getType()->isVoidType()) { 5808 if (Info.getLangOpts().CPlusPlus0x) 5809 Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_nonliteral) 5810 << E->getType(); 5811 else 5812 Info.CCEDiag(E->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 5813 if (!EvaluateVoid(E, Info)) 5814 return false; 5815 } else if (Info.getLangOpts().CPlusPlus0x) { 5816 Info.Diag(E->getExprLoc(), diag::note_constexpr_nonliteral) << E->getType(); 5817 return false; 5818 } else { 5819 Info.Diag(E->getExprLoc(), diag::note_invalid_subexpr_in_const_expr); 5820 return false; 5821 } 5822 5823 return true; 5824} 5825 5826/// EvaluateConstantExpression - Evaluate an expression as a constant expression 5827/// in-place in an APValue. In some cases, the in-place evaluation is essential, 5828/// since later initializers for an object can indirectly refer to subobjects 5829/// which were initialized earlier. 5830static bool EvaluateConstantExpression(APValue &Result, EvalInfo &Info, 5831 const LValue &This, const Expr *E, 5832 CheckConstantExpressionKind CCEK) { 5833 if (!CheckLiteralType(Info, E)) 5834 return false; 5835 5836 if (E->isRValue()) { 5837 // Evaluate arrays and record types in-place, so that later initializers can 5838 // refer to earlier-initialized members of the object. 5839 if (E->getType()->isArrayType()) 5840 return EvaluateArray(E, This, Result, Info); 5841 else if (E->getType()->isRecordType()) 5842 return EvaluateRecord(E, This, Result, Info); 5843 } 5844 5845 // For any other type, in-place evaluation is unimportant. 5846 CCValue CoreConstResult; 5847 return Evaluate(CoreConstResult, Info, E) && 5848 CheckConstantExpression(Info, E, CoreConstResult, Result, CCEK); 5849} 5850 5851/// EvaluateAsRValue - Try to evaluate this expression, performing an implicit 5852/// lvalue-to-rvalue cast if it is an lvalue. 5853static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) { 5854 if (!CheckLiteralType(Info, E)) 5855 return false; 5856 5857 CCValue Value; 5858 if (!::Evaluate(Value, Info, E)) 5859 return false; 5860 5861 if (E->isGLValue()) { 5862 LValue LV; 5863 LV.setFrom(Value); 5864 if (!HandleLValueToRValueConversion(Info, E, E->getType(), LV, Value)) 5865 return false; 5866 } 5867 5868 // Check this core constant expression is a constant expression, and if so, 5869 // convert it to one. 5870 return CheckConstantExpression(Info, E, Value, Result); 5871} 5872 5873/// EvaluateAsRValue - Return true if this is a constant which we can fold using 5874/// any crazy technique (that has nothing to do with language standards) that 5875/// we want to. If this function returns true, it returns the folded constant 5876/// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion 5877/// will be applied to the result. 5878bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx) const { 5879 // Fast-path evaluations of integer literals, since we sometimes see files 5880 // containing vast quantities of these. 5881 if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(this)) { 5882 Result.Val = APValue(APSInt(L->getValue(), 5883 L->getType()->isUnsignedIntegerType())); 5884 return true; 5885 } 5886 5887 // FIXME: Evaluating values of large array and record types can cause 5888 // performance problems. Only do so in C++11 for now. 5889 if (isRValue() && (getType()->isArrayType() || getType()->isRecordType()) && 5890 !Ctx.getLangOptions().CPlusPlus0x) 5891 return false; 5892 5893 EvalInfo Info(Ctx, Result); 5894 return ::EvaluateAsRValue(Info, this, Result.Val); 5895} 5896 5897bool Expr::EvaluateAsBooleanCondition(bool &Result, 5898 const ASTContext &Ctx) const { 5899 EvalResult Scratch; 5900 return EvaluateAsRValue(Scratch, Ctx) && 5901 HandleConversionToBool(CCValue(const_cast<ASTContext&>(Ctx), 5902 Scratch.Val, CCValue::GlobalValue()), 5903 Result); 5904} 5905 5906bool Expr::EvaluateAsInt(APSInt &Result, const ASTContext &Ctx, 5907 SideEffectsKind AllowSideEffects) const { 5908 if (!getType()->isIntegralOrEnumerationType()) 5909 return false; 5910 5911 EvalResult ExprResult; 5912 if (!EvaluateAsRValue(ExprResult, Ctx) || !ExprResult.Val.isInt() || 5913 (!AllowSideEffects && ExprResult.HasSideEffects)) 5914 return false; 5915 5916 Result = ExprResult.Val.getInt(); 5917 return true; 5918} 5919 5920bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx) const { 5921 EvalInfo Info(Ctx, Result); 5922 5923 LValue LV; 5924 return EvaluateLValue(this, LV, Info) && !Result.HasSideEffects && 5925 CheckLValueConstantExpression(Info, this, LV, Result.Val, 5926 CCEK_Constant); 5927} 5928 5929bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx, 5930 const VarDecl *VD, 5931 llvm::SmallVectorImpl<PartialDiagnosticAt> &Notes) const { 5932 // FIXME: Evaluating initializers for large array and record types can cause 5933 // performance problems. Only do so in C++11 for now. 5934 if (isRValue() && (getType()->isArrayType() || getType()->isRecordType()) && 5935 !Ctx.getLangOptions().CPlusPlus0x) 5936 return false; 5937 5938 Expr::EvalStatus EStatus; 5939 EStatus.Diag = &Notes; 5940 5941 EvalInfo InitInfo(Ctx, EStatus); 5942 InitInfo.setEvaluatingDecl(VD, Value); 5943 5944 if (!CheckLiteralType(InitInfo, this)) 5945 return false; 5946 5947 LValue LVal; 5948 LVal.set(VD); 5949 5950 // C++11 [basic.start.init]p2: 5951 // Variables with static storage duration or thread storage duration shall be 5952 // zero-initialized before any other initialization takes place. 5953 // This behavior is not present in C. 5954 if (Ctx.getLangOptions().CPlusPlus && !VD->hasLocalStorage() && 5955 !VD->getType()->isReferenceType()) { 5956 ImplicitValueInitExpr VIE(VD->getType()); 5957 if (!EvaluateConstantExpression(Value, InitInfo, LVal, &VIE)) 5958 return false; 5959 } 5960 5961 return EvaluateConstantExpression(Value, InitInfo, LVal, this) && 5962 !EStatus.HasSideEffects; 5963} 5964 5965/// isEvaluatable - Call EvaluateAsRValue to see if this expression can be 5966/// constant folded, but discard the result. 5967bool Expr::isEvaluatable(const ASTContext &Ctx) const { 5968 EvalResult Result; 5969 return EvaluateAsRValue(Result, Ctx) && !Result.HasSideEffects; 5970} 5971 5972bool Expr::HasSideEffects(const ASTContext &Ctx) const { 5973 return HasSideEffect(Ctx).Visit(this); 5974} 5975 5976APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx) const { 5977 EvalResult EvalResult; 5978 bool Result = EvaluateAsRValue(EvalResult, Ctx); 5979 (void)Result; 5980 assert(Result && "Could not evaluate expression"); 5981 assert(EvalResult.Val.isInt() && "Expression did not evaluate to integer"); 5982 5983 return EvalResult.Val.getInt(); 5984} 5985 5986 bool Expr::EvalResult::isGlobalLValue() const { 5987 assert(Val.isLValue()); 5988 return IsGlobalLValue(Val.getLValueBase()); 5989 } 5990 5991 5992/// isIntegerConstantExpr - this recursive routine will test if an expression is 5993/// an integer constant expression. 5994 5995/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero, 5996/// comma, etc 5997/// 5998/// FIXME: Handle offsetof. Two things to do: Handle GCC's __builtin_offsetof 5999/// to support gcc 4.0+ and handle the idiom GCC recognizes with a null pointer 6000/// cast+dereference. 6001 6002// CheckICE - This function does the fundamental ICE checking: the returned 6003// ICEDiag contains a Val of 0, 1, or 2, and a possibly null SourceLocation. 6004// Note that to reduce code duplication, this helper does no evaluation 6005// itself; the caller checks whether the expression is evaluatable, and 6006// in the rare cases where CheckICE actually cares about the evaluated 6007// value, it calls into Evalute. 6008// 6009// Meanings of Val: 6010// 0: This expression is an ICE. 6011// 1: This expression is not an ICE, but if it isn't evaluated, it's 6012// a legal subexpression for an ICE. This return value is used to handle 6013// the comma operator in C99 mode. 6014// 2: This expression is not an ICE, and is not a legal subexpression for one. 6015 6016namespace { 6017 6018struct ICEDiag { 6019 unsigned Val; 6020 SourceLocation Loc; 6021 6022 public: 6023 ICEDiag(unsigned v, SourceLocation l) : Val(v), Loc(l) {} 6024 ICEDiag() : Val(0) {} 6025}; 6026 6027} 6028 6029static ICEDiag NoDiag() { return ICEDiag(); } 6030 6031static ICEDiag CheckEvalInICE(const Expr* E, ASTContext &Ctx) { 6032 Expr::EvalResult EVResult; 6033 if (!E->EvaluateAsRValue(EVResult, Ctx) || EVResult.HasSideEffects || 6034 !EVResult.Val.isInt()) { 6035 return ICEDiag(2, E->getLocStart()); 6036 } 6037 return NoDiag(); 6038} 6039 6040static ICEDiag CheckICE(const Expr* E, ASTContext &Ctx) { 6041 assert(!E->isValueDependent() && "Should not see value dependent exprs!"); 6042 if (!E->getType()->isIntegralOrEnumerationType()) { 6043 return ICEDiag(2, E->getLocStart()); 6044 } 6045 6046 switch (E->getStmtClass()) { 6047#define ABSTRACT_STMT(Node) 6048#define STMT(Node, Base) case Expr::Node##Class: 6049#define EXPR(Node, Base) 6050#include "clang/AST/StmtNodes.inc" 6051 case Expr::PredefinedExprClass: 6052 case Expr::FloatingLiteralClass: 6053 case Expr::ImaginaryLiteralClass: 6054 case Expr::StringLiteralClass: 6055 case Expr::ArraySubscriptExprClass: 6056 case Expr::MemberExprClass: 6057 case Expr::CompoundAssignOperatorClass: 6058 case Expr::CompoundLiteralExprClass: 6059 case Expr::ExtVectorElementExprClass: 6060 case Expr::DesignatedInitExprClass: 6061 case Expr::ImplicitValueInitExprClass: 6062 case Expr::ParenListExprClass: 6063 case Expr::VAArgExprClass: 6064 case Expr::AddrLabelExprClass: 6065 case Expr::StmtExprClass: 6066 case Expr::CXXMemberCallExprClass: 6067 case Expr::CUDAKernelCallExprClass: 6068 case Expr::CXXDynamicCastExprClass: 6069 case Expr::CXXTypeidExprClass: 6070 case Expr::CXXUuidofExprClass: 6071 case Expr::CXXNullPtrLiteralExprClass: 6072 case Expr::CXXThisExprClass: 6073 case Expr::CXXThrowExprClass: 6074 case Expr::CXXNewExprClass: 6075 case Expr::CXXDeleteExprClass: 6076 case Expr::CXXPseudoDestructorExprClass: 6077 case Expr::UnresolvedLookupExprClass: 6078 case Expr::DependentScopeDeclRefExprClass: 6079 case Expr::CXXConstructExprClass: 6080 case Expr::CXXBindTemporaryExprClass: 6081 case Expr::ExprWithCleanupsClass: 6082 case Expr::CXXTemporaryObjectExprClass: 6083 case Expr::CXXUnresolvedConstructExprClass: 6084 case Expr::CXXDependentScopeMemberExprClass: 6085 case Expr::UnresolvedMemberExprClass: 6086 case Expr::ObjCStringLiteralClass: 6087 case Expr::ObjCEncodeExprClass: 6088 case Expr::ObjCMessageExprClass: 6089 case Expr::ObjCSelectorExprClass: 6090 case Expr::ObjCProtocolExprClass: 6091 case Expr::ObjCIvarRefExprClass: 6092 case Expr::ObjCPropertyRefExprClass: 6093 case Expr::ObjCIsaExprClass: 6094 case Expr::ShuffleVectorExprClass: 6095 case Expr::BlockExprClass: 6096 case Expr::BlockDeclRefExprClass: 6097 case Expr::NoStmtClass: 6098 case Expr::OpaqueValueExprClass: 6099 case Expr::PackExpansionExprClass: 6100 case Expr::SubstNonTypeTemplateParmPackExprClass: 6101 case Expr::AsTypeExprClass: 6102 case Expr::ObjCIndirectCopyRestoreExprClass: 6103 case Expr::MaterializeTemporaryExprClass: 6104 case Expr::PseudoObjectExprClass: 6105 case Expr::AtomicExprClass: 6106 case Expr::InitListExprClass: 6107 case Expr::LambdaExprClass: 6108 return ICEDiag(2, E->getLocStart()); 6109 6110 case Expr::SizeOfPackExprClass: 6111 case Expr::GNUNullExprClass: 6112 // GCC considers the GNU __null value to be an integral constant expression. 6113 return NoDiag(); 6114 6115 case Expr::SubstNonTypeTemplateParmExprClass: 6116 return 6117 CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx); 6118 6119 case Expr::ParenExprClass: 6120 return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx); 6121 case Expr::GenericSelectionExprClass: 6122 return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx); 6123 case Expr::IntegerLiteralClass: 6124 case Expr::CharacterLiteralClass: 6125 case Expr::CXXBoolLiteralExprClass: 6126 case Expr::CXXScalarValueInitExprClass: 6127 case Expr::UnaryTypeTraitExprClass: 6128 case Expr::BinaryTypeTraitExprClass: 6129 case Expr::ArrayTypeTraitExprClass: 6130 case Expr::ExpressionTraitExprClass: 6131 case Expr::CXXNoexceptExprClass: 6132 return NoDiag(); 6133 case Expr::CallExprClass: 6134 case Expr::CXXOperatorCallExprClass: { 6135 // C99 6.6/3 allows function calls within unevaluated subexpressions of 6136 // constant expressions, but they can never be ICEs because an ICE cannot 6137 // contain an operand of (pointer to) function type. 6138 const CallExpr *CE = cast<CallExpr>(E); 6139 if (CE->isBuiltinCall()) 6140 return CheckEvalInICE(E, Ctx); 6141 return ICEDiag(2, E->getLocStart()); 6142 } 6143 case Expr::DeclRefExprClass: 6144 if (isa<EnumConstantDecl>(cast<DeclRefExpr>(E)->getDecl())) 6145 return NoDiag(); 6146 if (Ctx.getLangOptions().CPlusPlus && IsConstNonVolatile(E->getType())) { 6147 const NamedDecl *D = cast<DeclRefExpr>(E)->getDecl(); 6148 6149 // Parameter variables are never constants. Without this check, 6150 // getAnyInitializer() can find a default argument, which leads 6151 // to chaos. 6152 if (isa<ParmVarDecl>(D)) 6153 return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation()); 6154 6155 // C++ 7.1.5.1p2 6156 // A variable of non-volatile const-qualified integral or enumeration 6157 // type initialized by an ICE can be used in ICEs. 6158 if (const VarDecl *Dcl = dyn_cast<VarDecl>(D)) { 6159 if (!Dcl->getType()->isIntegralOrEnumerationType()) 6160 return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation()); 6161 6162 const VarDecl *VD; 6163 // Look for a declaration of this variable that has an initializer, and 6164 // check whether it is an ICE. 6165 if (Dcl->getAnyInitializer(VD) && VD->checkInitIsICE()) 6166 return NoDiag(); 6167 else 6168 return ICEDiag(2, cast<DeclRefExpr>(E)->getLocation()); 6169 } 6170 } 6171 return ICEDiag(2, E->getLocStart()); 6172 case Expr::UnaryOperatorClass: { 6173 const UnaryOperator *Exp = cast<UnaryOperator>(E); 6174 switch (Exp->getOpcode()) { 6175 case UO_PostInc: 6176 case UO_PostDec: 6177 case UO_PreInc: 6178 case UO_PreDec: 6179 case UO_AddrOf: 6180 case UO_Deref: 6181 // C99 6.6/3 allows increment and decrement within unevaluated 6182 // subexpressions of constant expressions, but they can never be ICEs 6183 // because an ICE cannot contain an lvalue operand. 6184 return ICEDiag(2, E->getLocStart()); 6185 case UO_Extension: 6186 case UO_LNot: 6187 case UO_Plus: 6188 case UO_Minus: 6189 case UO_Not: 6190 case UO_Real: 6191 case UO_Imag: 6192 return CheckICE(Exp->getSubExpr(), Ctx); 6193 } 6194 6195 // OffsetOf falls through here. 6196 } 6197 case Expr::OffsetOfExprClass: { 6198 // Note that per C99, offsetof must be an ICE. And AFAIK, using 6199 // EvaluateAsRValue matches the proposed gcc behavior for cases like 6200 // "offsetof(struct s{int x[4];}, x[1.0])". This doesn't affect 6201 // compliance: we should warn earlier for offsetof expressions with 6202 // array subscripts that aren't ICEs, and if the array subscripts 6203 // are ICEs, the value of the offsetof must be an integer constant. 6204 return CheckEvalInICE(E, Ctx); 6205 } 6206 case Expr::UnaryExprOrTypeTraitExprClass: { 6207 const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E); 6208 if ((Exp->getKind() == UETT_SizeOf) && 6209 Exp->getTypeOfArgument()->isVariableArrayType()) 6210 return ICEDiag(2, E->getLocStart()); 6211 return NoDiag(); 6212 } 6213 case Expr::BinaryOperatorClass: { 6214 const BinaryOperator *Exp = cast<BinaryOperator>(E); 6215 switch (Exp->getOpcode()) { 6216 case BO_PtrMemD: 6217 case BO_PtrMemI: 6218 case BO_Assign: 6219 case BO_MulAssign: 6220 case BO_DivAssign: 6221 case BO_RemAssign: 6222 case BO_AddAssign: 6223 case BO_SubAssign: 6224 case BO_ShlAssign: 6225 case BO_ShrAssign: 6226 case BO_AndAssign: 6227 case BO_XorAssign: 6228 case BO_OrAssign: 6229 // C99 6.6/3 allows assignments within unevaluated subexpressions of 6230 // constant expressions, but they can never be ICEs because an ICE cannot 6231 // contain an lvalue operand. 6232 return ICEDiag(2, E->getLocStart()); 6233 6234 case BO_Mul: 6235 case BO_Div: 6236 case BO_Rem: 6237 case BO_Add: 6238 case BO_Sub: 6239 case BO_Shl: 6240 case BO_Shr: 6241 case BO_LT: 6242 case BO_GT: 6243 case BO_LE: 6244 case BO_GE: 6245 case BO_EQ: 6246 case BO_NE: 6247 case BO_And: 6248 case BO_Xor: 6249 case BO_Or: 6250 case BO_Comma: { 6251 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx); 6252 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx); 6253 if (Exp->getOpcode() == BO_Div || 6254 Exp->getOpcode() == BO_Rem) { 6255 // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure 6256 // we don't evaluate one. 6257 if (LHSResult.Val == 0 && RHSResult.Val == 0) { 6258 llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx); 6259 if (REval == 0) 6260 return ICEDiag(1, E->getLocStart()); 6261 if (REval.isSigned() && REval.isAllOnesValue()) { 6262 llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx); 6263 if (LEval.isMinSignedValue()) 6264 return ICEDiag(1, E->getLocStart()); 6265 } 6266 } 6267 } 6268 if (Exp->getOpcode() == BO_Comma) { 6269 if (Ctx.getLangOptions().C99) { 6270 // C99 6.6p3 introduces a strange edge case: comma can be in an ICE 6271 // if it isn't evaluated. 6272 if (LHSResult.Val == 0 && RHSResult.Val == 0) 6273 return ICEDiag(1, E->getLocStart()); 6274 } else { 6275 // In both C89 and C++, commas in ICEs are illegal. 6276 return ICEDiag(2, E->getLocStart()); 6277 } 6278 } 6279 if (LHSResult.Val >= RHSResult.Val) 6280 return LHSResult; 6281 return RHSResult; 6282 } 6283 case BO_LAnd: 6284 case BO_LOr: { 6285 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx); 6286 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx); 6287 if (LHSResult.Val == 0 && RHSResult.Val == 1) { 6288 // Rare case where the RHS has a comma "side-effect"; we need 6289 // to actually check the condition to see whether the side 6290 // with the comma is evaluated. 6291 if ((Exp->getOpcode() == BO_LAnd) != 6292 (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0)) 6293 return RHSResult; 6294 return NoDiag(); 6295 } 6296 6297 if (LHSResult.Val >= RHSResult.Val) 6298 return LHSResult; 6299 return RHSResult; 6300 } 6301 } 6302 } 6303 case Expr::ImplicitCastExprClass: 6304 case Expr::CStyleCastExprClass: 6305 case Expr::CXXFunctionalCastExprClass: 6306 case Expr::CXXStaticCastExprClass: 6307 case Expr::CXXReinterpretCastExprClass: 6308 case Expr::CXXConstCastExprClass: 6309 case Expr::ObjCBridgedCastExprClass: { 6310 const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr(); 6311 if (isa<ExplicitCastExpr>(E)) { 6312 if (const FloatingLiteral *FL 6313 = dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) { 6314 unsigned DestWidth = Ctx.getIntWidth(E->getType()); 6315 bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType(); 6316 APSInt IgnoredVal(DestWidth, !DestSigned); 6317 bool Ignored; 6318 // If the value does not fit in the destination type, the behavior is 6319 // undefined, so we are not required to treat it as a constant 6320 // expression. 6321 if (FL->getValue().convertToInteger(IgnoredVal, 6322 llvm::APFloat::rmTowardZero, 6323 &Ignored) & APFloat::opInvalidOp) 6324 return ICEDiag(2, E->getLocStart()); 6325 return NoDiag(); 6326 } 6327 } 6328 switch (cast<CastExpr>(E)->getCastKind()) { 6329 case CK_LValueToRValue: 6330 case CK_AtomicToNonAtomic: 6331 case CK_NonAtomicToAtomic: 6332 case CK_NoOp: 6333 case CK_IntegralToBoolean: 6334 case CK_IntegralCast: 6335 return CheckICE(SubExpr, Ctx); 6336 default: 6337 return ICEDiag(2, E->getLocStart()); 6338 } 6339 } 6340 case Expr::BinaryConditionalOperatorClass: { 6341 const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E); 6342 ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx); 6343 if (CommonResult.Val == 2) return CommonResult; 6344 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx); 6345 if (FalseResult.Val == 2) return FalseResult; 6346 if (CommonResult.Val == 1) return CommonResult; 6347 if (FalseResult.Val == 1 && 6348 Exp->getCommon()->EvaluateKnownConstInt(Ctx) == 0) return NoDiag(); 6349 return FalseResult; 6350 } 6351 case Expr::ConditionalOperatorClass: { 6352 const ConditionalOperator *Exp = cast<ConditionalOperator>(E); 6353 // If the condition (ignoring parens) is a __builtin_constant_p call, 6354 // then only the true side is actually considered in an integer constant 6355 // expression, and it is fully evaluated. This is an important GNU 6356 // extension. See GCC PR38377 for discussion. 6357 if (const CallExpr *CallCE 6358 = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts())) 6359 if (CallCE->isBuiltinCall() == Builtin::BI__builtin_constant_p) 6360 return CheckEvalInICE(E, Ctx); 6361 ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx); 6362 if (CondResult.Val == 2) 6363 return CondResult; 6364 6365 ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx); 6366 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx); 6367 6368 if (TrueResult.Val == 2) 6369 return TrueResult; 6370 if (FalseResult.Val == 2) 6371 return FalseResult; 6372 if (CondResult.Val == 1) 6373 return CondResult; 6374 if (TrueResult.Val == 0 && FalseResult.Val == 0) 6375 return NoDiag(); 6376 // Rare case where the diagnostics depend on which side is evaluated 6377 // Note that if we get here, CondResult is 0, and at least one of 6378 // TrueResult and FalseResult is non-zero. 6379 if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0) { 6380 return FalseResult; 6381 } 6382 return TrueResult; 6383 } 6384 case Expr::CXXDefaultArgExprClass: 6385 return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx); 6386 case Expr::ChooseExprClass: { 6387 return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(Ctx), Ctx); 6388 } 6389 } 6390 6391 llvm_unreachable("Invalid StmtClass!"); 6392} 6393 6394/// Evaluate an expression as a C++11 integral constant expression. 6395static bool EvaluateCPlusPlus11IntegralConstantExpr(ASTContext &Ctx, 6396 const Expr *E, 6397 llvm::APSInt *Value, 6398 SourceLocation *Loc) { 6399 if (!E->getType()->isIntegralOrEnumerationType()) { 6400 if (Loc) *Loc = E->getExprLoc(); 6401 return false; 6402 } 6403 6404 APValue Result; 6405 if (!E->isCXX11ConstantExpr(Ctx, &Result, Loc)) 6406 return false; 6407 6408 assert(Result.isInt() && "pointer cast to int is not an ICE"); 6409 if (Value) *Value = Result.getInt(); 6410 return true; 6411} 6412 6413bool Expr::isIntegerConstantExpr(ASTContext &Ctx, SourceLocation *Loc) const { 6414 if (Ctx.getLangOptions().CPlusPlus0x) 6415 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, 0, Loc); 6416 6417 ICEDiag d = CheckICE(this, Ctx); 6418 if (d.Val != 0) { 6419 if (Loc) *Loc = d.Loc; 6420 return false; 6421 } 6422 return true; 6423} 6424 6425bool Expr::isIntegerConstantExpr(llvm::APSInt &Value, ASTContext &Ctx, 6426 SourceLocation *Loc, bool isEvaluated) const { 6427 if (Ctx.getLangOptions().CPlusPlus0x) 6428 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc); 6429 6430 if (!isIntegerConstantExpr(Ctx, Loc)) 6431 return false; 6432 if (!EvaluateAsInt(Value, Ctx)) 6433 llvm_unreachable("ICE cannot be evaluated!"); 6434 return true; 6435} 6436 6437bool Expr::isCXX11ConstantExpr(ASTContext &Ctx, APValue *Result, 6438 SourceLocation *Loc) const { 6439 // We support this checking in C++98 mode in order to diagnose compatibility 6440 // issues. 6441 assert(Ctx.getLangOptions().CPlusPlus); 6442 6443 Expr::EvalStatus Status; 6444 llvm::SmallVector<PartialDiagnosticAt, 8> Diags; 6445 Status.Diag = &Diags; 6446 EvalInfo Info(Ctx, Status); 6447 6448 APValue Scratch; 6449 bool IsConstExpr = ::EvaluateAsRValue(Info, this, Result ? *Result : Scratch); 6450 6451 if (!Diags.empty()) { 6452 IsConstExpr = false; 6453 if (Loc) *Loc = Diags[0].first; 6454 } else if (!IsConstExpr) { 6455 // FIXME: This shouldn't happen. 6456 if (Loc) *Loc = getExprLoc(); 6457 } 6458 6459 return IsConstExpr; 6460} 6461 6462bool Expr::isPotentialConstantExpr(const FunctionDecl *FD, 6463 llvm::SmallVectorImpl< 6464 PartialDiagnosticAt> &Diags) { 6465 // FIXME: It would be useful to check constexpr function templates, but at the 6466 // moment the constant expression evaluator cannot cope with the non-rigorous 6467 // ASTs which we build for dependent expressions. 6468 if (FD->isDependentContext()) 6469 return true; 6470 6471 Expr::EvalStatus Status; 6472 Status.Diag = &Diags; 6473 6474 EvalInfo Info(FD->getASTContext(), Status); 6475 Info.CheckingPotentialConstantExpression = true; 6476 6477 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD); 6478 const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : 0; 6479 6480 // FIXME: Fabricate an arbitrary expression on the stack and pretend that it 6481 // is a temporary being used as the 'this' pointer. 6482 LValue This; 6483 ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy); 6484 This.set(&VIE, Info.CurrentCall); 6485 6486 APValue Scratch; 6487 ArrayRef<const Expr*> Args; 6488 6489 SourceLocation Loc = FD->getLocation(); 6490 6491 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) { 6492 HandleConstructorCall(Loc, This, Args, CD, Info, Scratch); 6493 } else 6494 HandleFunctionCall(Loc, FD, (MD && MD->isInstance()) ? &This : 0, 6495 Args, FD->getBody(), Info, Scratch); 6496 6497 return Diags.empty(); 6498} 6499