//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements semantic analysis for statements. // //===----------------------------------------------------------------------===// #include "clang/Sema/SemaInternal.h" #include "clang/Sema/Scope.h" #include "clang/Sema/ScopeInfo.h" #include "clang/Sema/Initialization.h" #include "clang/Sema/Lookup.h" #include "clang/AST/ASTContext.h" #include "clang/AST/CharUnits.h" #include "clang/AST/DeclObjC.h" #include "clang/AST/ExprCXX.h" #include "clang/AST/ExprObjC.h" #include "clang/AST/StmtObjC.h" #include "clang/AST/StmtCXX.h" #include "clang/AST/TypeLoc.h" #include "clang/Lex/Preprocessor.h" #include "clang/Basic/TargetInfo.h" #include "llvm/ADT/ArrayRef.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/SmallVector.h" using namespace clang; using namespace sema; StmtResult Sema::ActOnExprStmt(FullExprArg expr) { Expr *E = expr.get(); if (!E) // FIXME: FullExprArg has no error state? return StmtError(); // C99 6.8.3p2: The expression in an expression statement is evaluated as a // void expression for its side effects. Conversion to void allows any // operand, even incomplete types. // Same thing in for stmt first clause (when expr) and third clause. return Owned(static_cast(E)); } StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, bool HasLeadingEmptyMacro) { return Owned(new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro)); } StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, SourceLocation EndLoc) { DeclGroupRef DG = dg.getAsVal(); // If we have an invalid decl, just return an error. if (DG.isNull()) return StmtError(); return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); } void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { DeclGroupRef DG = dg.getAsVal(); // If we have an invalid decl, just return. if (DG.isNull() || !DG.isSingleDecl()) return; VarDecl *var = cast(DG.getSingleDecl()); // suppress any potential 'unused variable' warning. var->setUsed(); // foreach variables are never actually initialized in the way that // the parser came up with. var->setInit(0); // In ARC, we don't need to retain the iteration variable of a fast // enumeration loop. Rather than actually trying to catch that // during declaration processing, we remove the consequences here. if (getLangOpts().ObjCAutoRefCount) { QualType type = var->getType(); // Only do this if we inferred the lifetime. Inferred lifetime // will show up as a local qualifier because explicit lifetime // should have shown up as an AttributedType instead. if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) { // Add 'const' and mark the variable as pseudo-strong. var->setType(type.withConst()); var->setARCPseudoStrong(true); } } } /// \brief Diagnose unused '==' and '!=' as likely typos for '=' or '|='. /// /// Adding a cast to void (or other expression wrappers) will prevent the /// warning from firing. static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) { SourceLocation Loc; bool IsNotEqual, CanAssign; if (const BinaryOperator *Op = dyn_cast(E)) { if (Op->getOpcode() != BO_EQ && Op->getOpcode() != BO_NE) return false; Loc = Op->getOperatorLoc(); IsNotEqual = Op->getOpcode() == BO_NE; CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue(); } else if (const CXXOperatorCallExpr *Op = dyn_cast(E)) { if (Op->getOperator() != OO_EqualEqual && Op->getOperator() != OO_ExclaimEqual) return false; Loc = Op->getOperatorLoc(); IsNotEqual = Op->getOperator() == OO_ExclaimEqual; CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue(); } else { // Not a typo-prone comparison. return false; } // Suppress warnings when the operator, suspicious as it may be, comes from // a macro expansion. if (Loc.isMacroID()) return false; S.Diag(Loc, diag::warn_unused_comparison) << (unsigned)IsNotEqual << E->getSourceRange(); // If the LHS is a plausible entity to assign to, provide a fixit hint to // correct common typos. if (CanAssign) { if (IsNotEqual) S.Diag(Loc, diag::note_inequality_comparison_to_or_assign) << FixItHint::CreateReplacement(Loc, "|="); else S.Diag(Loc, diag::note_equality_comparison_to_assign) << FixItHint::CreateReplacement(Loc, "="); } return true; } void Sema::DiagnoseUnusedExprResult(const Stmt *S) { if (const LabelStmt *Label = dyn_cast_or_null(S)) return DiagnoseUnusedExprResult(Label->getSubStmt()); const Expr *E = dyn_cast_or_null(S); if (!E) return; SourceLocation Loc; SourceRange R1, R2; if (SourceMgr.isInSystemMacro(E->getExprLoc()) || !E->isUnusedResultAWarning(Loc, R1, R2, Context)) return; // Okay, we have an unused result. Depending on what the base expression is, // we might want to make a more specific diagnostic. Check for one of these // cases now. unsigned DiagID = diag::warn_unused_expr; if (const ExprWithCleanups *Temps = dyn_cast(E)) E = Temps->getSubExpr(); if (const CXXBindTemporaryExpr *TempExpr = dyn_cast(E)) E = TempExpr->getSubExpr(); if (DiagnoseUnusedComparison(*this, E)) return; E = E->IgnoreParenImpCasts(); if (const CallExpr *CE = dyn_cast(E)) { if (E->getType()->isVoidType()) return; // If the callee has attribute pure, const, or warn_unused_result, warn with // a more specific message to make it clear what is happening. if (const Decl *FD = CE->getCalleeDecl()) { if (FD->getAttr()) { Diag(Loc, diag::warn_unused_result) << R1 << R2; return; } if (FD->getAttr()) { Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; return; } if (FD->getAttr()) { Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; return; } } } else if (const ObjCMessageExpr *ME = dyn_cast(E)) { if (getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) { Diag(Loc, diag::err_arc_unused_init_message) << R1; return; } const ObjCMethodDecl *MD = ME->getMethodDecl(); if (MD && MD->getAttr()) { Diag(Loc, diag::warn_unused_result) << R1 << R2; return; } } else if (const PseudoObjectExpr *POE = dyn_cast(E)) { const Expr *Source = POE->getSyntacticForm(); if (isa(Source)) DiagID = diag::warn_unused_container_subscript_expr; else DiagID = diag::warn_unused_property_expr; } else if (const CXXFunctionalCastExpr *FC = dyn_cast(E)) { if (isa(FC->getSubExpr()) || isa(FC->getSubExpr())) return; } // Diagnose "(void*) blah" as a typo for "(void) blah". else if (const CStyleCastExpr *CE = dyn_cast(E)) { TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); QualType T = TI->getType(); // We really do want to use the non-canonical type here. if (T == Context.VoidPtrTy) { PointerTypeLoc TL = cast(TI->getTypeLoc()); Diag(Loc, diag::warn_unused_voidptr) << FixItHint::CreateRemoval(TL.getStarLoc()); return; } } DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2); } void Sema::ActOnStartOfCompoundStmt() { PushCompoundScope(); } void Sema::ActOnFinishOfCompoundStmt() { PopCompoundScope(); } sema::CompoundScopeInfo &Sema::getCurCompoundScope() const { return getCurFunction()->CompoundScopes.back(); } StmtResult Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, MultiStmtArg elts, bool isStmtExpr) { unsigned NumElts = elts.size(); Stmt **Elts = reinterpret_cast(elts.release()); // If we're in C89 mode, check that we don't have any decls after stmts. If // so, emit an extension diagnostic. if (!getLangOpts().C99 && !getLangOpts().CPlusPlus) { // Note that __extension__ can be around a decl. unsigned i = 0; // Skip over all declarations. for (; i != NumElts && isa(Elts[i]); ++i) /*empty*/; // We found the end of the list or a statement. Scan for another declstmt. for (; i != NumElts && !isa(Elts[i]); ++i) /*empty*/; if (i != NumElts) { Decl *D = *cast(Elts[i])->decl_begin(); Diag(D->getLocation(), diag::ext_mixed_decls_code); } } // Warn about unused expressions in statements. for (unsigned i = 0; i != NumElts; ++i) { // Ignore statements that are last in a statement expression. if (isStmtExpr && i == NumElts - 1) continue; DiagnoseUnusedExprResult(Elts[i]); } // Check for suspicious empty body (null statement) in `for' and `while' // statements. Don't do anything for template instantiations, this just adds // noise. if (NumElts != 0 && !CurrentInstantiationScope && getCurCompoundScope().HasEmptyLoopBodies) { for (unsigned i = 0; i != NumElts - 1; ++i) DiagnoseEmptyLoopBody(Elts[i], Elts[i + 1]); } return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); } StmtResult Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, SourceLocation DotDotDotLoc, Expr *RHSVal, SourceLocation ColonLoc) { assert((LHSVal != 0) && "missing expression in case statement"); if (getCurFunction()->SwitchStack.empty()) { Diag(CaseLoc, diag::err_case_not_in_switch); return StmtError(); } if (!getLangOpts().CPlusPlus0x) { // C99 6.8.4.2p3: The expression shall be an integer constant. // However, GCC allows any evaluatable integer expression. if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent()) { LHSVal = VerifyIntegerConstantExpression(LHSVal).take(); if (!LHSVal) return StmtError(); } // GCC extension: The expression shall be an integer constant. if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent()) { RHSVal = VerifyIntegerConstantExpression(RHSVal).take(); // Recover from an error by just forgetting about it. } } CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, ColonLoc); getCurFunction()->SwitchStack.back()->addSwitchCase(CS); return Owned(CS); } /// ActOnCaseStmtBody - This installs a statement as the body of a case. void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { DiagnoseUnusedExprResult(SubStmt); CaseStmt *CS = static_cast(caseStmt); CS->setSubStmt(SubStmt); } StmtResult Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, Stmt *SubStmt, Scope *CurScope) { DiagnoseUnusedExprResult(SubStmt); if (getCurFunction()->SwitchStack.empty()) { Diag(DefaultLoc, diag::err_default_not_in_switch); return Owned(SubStmt); } DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); getCurFunction()->SwitchStack.back()->addSwitchCase(DS); return Owned(DS); } StmtResult Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, SourceLocation ColonLoc, Stmt *SubStmt) { // If the label was multiply defined, reject it now. if (TheDecl->getStmt()) { Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); Diag(TheDecl->getLocation(), diag::note_previous_definition); return Owned(SubStmt); } // Otherwise, things are good. Fill in the declaration and return it. LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); TheDecl->setStmt(LS); if (!TheDecl->isGnuLocal()) TheDecl->setLocation(IdentLoc); return Owned(LS); } StmtResult Sema::ActOnAttributedStmt(SourceLocation AttrLoc, const AttrVec &Attrs, Stmt *SubStmt) { // Fill in the declaration and return it. Variable length will require to // change this to AttributedStmt::Create(Context, ....); // and probably using ArrayRef AttributedStmt *LS = new (Context) AttributedStmt(AttrLoc, Attrs, SubStmt); return Owned(LS); } StmtResult Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, Stmt *thenStmt, SourceLocation ElseLoc, Stmt *elseStmt) { ExprResult CondResult(CondVal.release()); VarDecl *ConditionVar = 0; if (CondVar) { ConditionVar = cast(CondVar); CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); if (CondResult.isInvalid()) return StmtError(); } Expr *ConditionExpr = CondResult.takeAs(); if (!ConditionExpr) return StmtError(); DiagnoseUnusedExprResult(thenStmt); if (!elseStmt) { DiagnoseEmptyStmtBody(ConditionExpr->getLocEnd(), thenStmt, diag::warn_empty_if_body); } DiagnoseUnusedExprResult(elseStmt); return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, thenStmt, ElseLoc, elseStmt)); } /// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have /// the specified width and sign. If an overflow occurs, detect it and emit /// the specified diagnostic. void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, unsigned NewWidth, bool NewSign, SourceLocation Loc, unsigned DiagID) { // Perform a conversion to the promoted condition type if needed. if (NewWidth > Val.getBitWidth()) { // If this is an extension, just do it. Val = Val.extend(NewWidth); Val.setIsSigned(NewSign); // If the input was signed and negative and the output is // unsigned, don't bother to warn: this is implementation-defined // behavior. // FIXME: Introduce a second, default-ignored warning for this case? } else if (NewWidth < Val.getBitWidth()) { // If this is a truncation, check for overflow. llvm::APSInt ConvVal(Val); ConvVal = ConvVal.trunc(NewWidth); ConvVal.setIsSigned(NewSign); ConvVal = ConvVal.extend(Val.getBitWidth()); ConvVal.setIsSigned(Val.isSigned()); if (ConvVal != Val) Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); // Regardless of whether a diagnostic was emitted, really do the // truncation. Val = Val.trunc(NewWidth); Val.setIsSigned(NewSign); } else if (NewSign != Val.isSigned()) { // Convert the sign to match the sign of the condition. This can cause // overflow as well: unsigned(INTMIN) // We don't diagnose this overflow, because it is implementation-defined // behavior. // FIXME: Introduce a second, default-ignored warning for this case? llvm::APSInt OldVal(Val); Val.setIsSigned(NewSign); } } namespace { struct CaseCompareFunctor { bool operator()(const std::pair &LHS, const llvm::APSInt &RHS) { return LHS.first < RHS; } bool operator()(const std::pair &LHS, const std::pair &RHS) { return LHS.first < RHS.first; } bool operator()(const llvm::APSInt &LHS, const std::pair &RHS) { return LHS < RHS.first; } }; } /// CmpCaseVals - Comparison predicate for sorting case values. /// static bool CmpCaseVals(const std::pair& lhs, const std::pair& rhs) { if (lhs.first < rhs.first) return true; if (lhs.first == rhs.first && lhs.second->getCaseLoc().getRawEncoding() < rhs.second->getCaseLoc().getRawEncoding()) return true; return false; } /// CmpEnumVals - Comparison predicate for sorting enumeration values. /// static bool CmpEnumVals(const std::pair& lhs, const std::pair& rhs) { return lhs.first < rhs.first; } /// EqEnumVals - Comparison preficate for uniqing enumeration values. /// static bool EqEnumVals(const std::pair& lhs, const std::pair& rhs) { return lhs.first == rhs.first; } /// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of /// potentially integral-promoted expression @p expr. static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) { if (ExprWithCleanups *cleanups = dyn_cast(expr)) expr = cleanups->getSubExpr(); while (ImplicitCastExpr *impcast = dyn_cast(expr)) { if (impcast->getCastKind() != CK_IntegralCast) break; expr = impcast->getSubExpr(); } return expr->getType(); } StmtResult Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, Decl *CondVar) { ExprResult CondResult; VarDecl *ConditionVar = 0; if (CondVar) { ConditionVar = cast(CondVar); CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); if (CondResult.isInvalid()) return StmtError(); Cond = CondResult.release(); } if (!Cond) return StmtError(); CondResult = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, PDiag(diag::err_typecheck_statement_requires_integer), PDiag(diag::err_switch_incomplete_class_type) << Cond->getSourceRange(), PDiag(diag::err_switch_explicit_conversion), PDiag(diag::note_switch_conversion), PDiag(diag::err_switch_multiple_conversions), PDiag(diag::note_switch_conversion), PDiag(0), /*AllowScopedEnumerations*/ true); if (CondResult.isInvalid()) return StmtError(); Cond = CondResult.take(); // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. CondResult = UsualUnaryConversions(Cond); if (CondResult.isInvalid()) return StmtError(); Cond = CondResult.take(); if (!CondVar) { CheckImplicitConversions(Cond, SwitchLoc); CondResult = MaybeCreateExprWithCleanups(Cond); if (CondResult.isInvalid()) return StmtError(); Cond = CondResult.take(); } getCurFunction()->setHasBranchIntoScope(); SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); getCurFunction()->SwitchStack.push_back(SS); return Owned(SS); } static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { if (Val.getBitWidth() < BitWidth) Val = Val.extend(BitWidth); else if (Val.getBitWidth() > BitWidth) Val = Val.trunc(BitWidth); Val.setIsSigned(IsSigned); } StmtResult Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, Stmt *BodyStmt) { SwitchStmt *SS = cast(Switch); assert(SS == getCurFunction()->SwitchStack.back() && "switch stack missing push/pop!"); SS->setBody(BodyStmt, SwitchLoc); getCurFunction()->SwitchStack.pop_back(); Expr *CondExpr = SS->getCond(); if (!CondExpr) return StmtError(); QualType CondType = CondExpr->getType(); Expr *CondExprBeforePromotion = CondExpr; QualType CondTypeBeforePromotion = GetTypeBeforeIntegralPromotion(CondExprBeforePromotion); // C++ 6.4.2.p2: // Integral promotions are performed (on the switch condition). // // A case value unrepresentable by the original switch condition // type (before the promotion) doesn't make sense, even when it can // be represented by the promoted type. Therefore we need to find // the pre-promotion type of the switch condition. if (!CondExpr->isTypeDependent()) { // We have already converted the expression to an integral or enumeration // type, when we started the switch statement. If we don't have an // appropriate type now, just return an error. if (!CondType->isIntegralOrEnumerationType()) return StmtError(); if (CondExpr->isKnownToHaveBooleanValue()) { // switch(bool_expr) {...} is often a programmer error, e.g. // switch(n && mask) { ... } // Doh - should be "n & mask". // One can always use an if statement instead of switch(bool_expr). Diag(SwitchLoc, diag::warn_bool_switch_condition) << CondExpr->getSourceRange(); } } // Get the bitwidth of the switched-on value before promotions. We must // convert the integer case values to this width before comparison. bool HasDependentValue = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); unsigned CondWidth = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType(); // Accumulate all of the case values in a vector so that we can sort them // and detect duplicates. This vector contains the APInt for the case after // it has been converted to the condition type. typedef SmallVector, 64> CaseValsTy; CaseValsTy CaseVals; // Keep track of any GNU case ranges we see. The APSInt is the low value. typedef std::vector > CaseRangesTy; CaseRangesTy CaseRanges; DefaultStmt *TheDefaultStmt = 0; bool CaseListIsErroneous = false; for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; SC = SC->getNextSwitchCase()) { if (DefaultStmt *DS = dyn_cast(SC)) { if (TheDefaultStmt) { Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); // FIXME: Remove the default statement from the switch block so that // we'll return a valid AST. This requires recursing down the AST and // finding it, not something we are set up to do right now. For now, // just lop the entire switch stmt out of the AST. CaseListIsErroneous = true; } TheDefaultStmt = DS; } else { CaseStmt *CS = cast(SC); Expr *Lo = CS->getLHS(); if (Lo->isTypeDependent() || Lo->isValueDependent()) { HasDependentValue = true; break; } llvm::APSInt LoVal; if (getLangOpts().CPlusPlus0x) { // C++11 [stmt.switch]p2: the constant-expression shall be a converted // constant expression of the promoted type of the switch condition. ExprResult ConvLo = CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue); if (ConvLo.isInvalid()) { CaseListIsErroneous = true; continue; } Lo = ConvLo.take(); } else { // We already verified that the expression has a i-c-e value (C99 // 6.8.4.2p3) - get that value now. LoVal = Lo->EvaluateKnownConstInt(Context); // If the LHS is not the same type as the condition, insert an implicit // cast. Lo = DefaultLvalueConversion(Lo).take(); Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); } // Convert the value to the same width/sign as the condition had prior to // integral promotions. // // FIXME: This causes us to reject valid code: // switch ((char)c) { case 256: case 0: return 0; } // Here we claim there is a duplicated condition value, but there is not. ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, Lo->getLocStart(), diag::warn_case_value_overflow); CS->setLHS(Lo); // If this is a case range, remember it in CaseRanges, otherwise CaseVals. if (CS->getRHS()) { if (CS->getRHS()->isTypeDependent() || CS->getRHS()->isValueDependent()) { HasDependentValue = true; break; } CaseRanges.push_back(std::make_pair(LoVal, CS)); } else CaseVals.push_back(std::make_pair(LoVal, CS)); } } if (!HasDependentValue) { // If we don't have a default statement, check whether the // condition is constant. llvm::APSInt ConstantCondValue; bool HasConstantCond = false; if (!HasDependentValue && !TheDefaultStmt) { HasConstantCond = CondExprBeforePromotion->EvaluateAsInt(ConstantCondValue, Context, Expr::SE_AllowSideEffects); assert(!HasConstantCond || (ConstantCondValue.getBitWidth() == CondWidth && ConstantCondValue.isSigned() == CondIsSigned)); } bool ShouldCheckConstantCond = HasConstantCond; // Sort all the scalar case values so we can easily detect duplicates. std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); if (!CaseVals.empty()) { for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { if (ShouldCheckConstantCond && CaseVals[i].first == ConstantCondValue) ShouldCheckConstantCond = false; if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { // If we have a duplicate, report it. Diag(CaseVals[i].second->getLHS()->getLocStart(), diag::err_duplicate_case) << CaseVals[i].first.toString(10); Diag(CaseVals[i-1].second->getLHS()->getLocStart(), diag::note_duplicate_case_prev); // FIXME: We really want to remove the bogus case stmt from the // substmt, but we have no way to do this right now. CaseListIsErroneous = true; } } } // Detect duplicate case ranges, which usually don't exist at all in // the first place. if (!CaseRanges.empty()) { // Sort all the case ranges by their low value so we can easily detect // overlaps between ranges. std::stable_sort(CaseRanges.begin(), CaseRanges.end()); // Scan the ranges, computing the high values and removing empty ranges. std::vector HiVals; for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { llvm::APSInt &LoVal = CaseRanges[i].first; CaseStmt *CR = CaseRanges[i].second; Expr *Hi = CR->getRHS(); llvm::APSInt HiVal; if (getLangOpts().CPlusPlus0x) { // C++11 [stmt.switch]p2: the constant-expression shall be a converted // constant expression of the promoted type of the switch condition. ExprResult ConvHi = CheckConvertedConstantExpression(Hi, CondType, HiVal, CCEK_CaseValue); if (ConvHi.isInvalid()) { CaseListIsErroneous = true; continue; } Hi = ConvHi.take(); } else { HiVal = Hi->EvaluateKnownConstInt(Context); // If the RHS is not the same type as the condition, insert an // implicit cast. Hi = DefaultLvalueConversion(Hi).take(); Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); } // Convert the value to the same width/sign as the condition. ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, Hi->getLocStart(), diag::warn_case_value_overflow); CR->setRHS(Hi); // If the low value is bigger than the high value, the case is empty. if (LoVal > HiVal) { Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) << SourceRange(CR->getLHS()->getLocStart(), Hi->getLocEnd()); CaseRanges.erase(CaseRanges.begin()+i); --i, --e; continue; } if (ShouldCheckConstantCond && LoVal <= ConstantCondValue && ConstantCondValue <= HiVal) ShouldCheckConstantCond = false; HiVals.push_back(HiVal); } // Rescan the ranges, looking for overlap with singleton values and other // ranges. Since the range list is sorted, we only need to compare case // ranges with their neighbors. for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { llvm::APSInt &CRLo = CaseRanges[i].first; llvm::APSInt &CRHi = HiVals[i]; CaseStmt *CR = CaseRanges[i].second; // Check to see whether the case range overlaps with any // singleton cases. CaseStmt *OverlapStmt = 0; llvm::APSInt OverlapVal(32); // Find the smallest value >= the lower bound. If I is in the // case range, then we have overlap. CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), CaseVals.end(), CRLo, CaseCompareFunctor()); if (I != CaseVals.end() && I->first < CRHi) { OverlapVal = I->first; // Found overlap with scalar. OverlapStmt = I->second; } // Find the smallest value bigger than the upper bound. I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); if (I != CaseVals.begin() && (I-1)->first >= CRLo) { OverlapVal = (I-1)->first; // Found overlap with scalar. OverlapStmt = (I-1)->second; } // Check to see if this case stmt overlaps with the subsequent // case range. if (i && CRLo <= HiVals[i-1]) { OverlapVal = HiVals[i-1]; // Found overlap with range. OverlapStmt = CaseRanges[i-1].second; } if (OverlapStmt) { // If we have a duplicate, report it. Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) << OverlapVal.toString(10); Diag(OverlapStmt->getLHS()->getLocStart(), diag::note_duplicate_case_prev); // FIXME: We really want to remove the bogus case stmt from the // substmt, but we have no way to do this right now. CaseListIsErroneous = true; } } } // Complain if we have a constant condition and we didn't find a match. if (!CaseListIsErroneous && ShouldCheckConstantCond) { // TODO: it would be nice if we printed enums as enums, chars as // chars, etc. Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) << ConstantCondValue.toString(10) << CondExpr->getSourceRange(); } // Check to see if switch is over an Enum and handles all of its // values. We only issue a warning if there is not 'default:', but // we still do the analysis to preserve this information in the AST // (which can be used by flow-based analyes). // const EnumType *ET = CondTypeBeforePromotion->getAs(); // If switch has default case, then ignore it. if (!CaseListIsErroneous && !HasConstantCond && ET) { const EnumDecl *ED = ET->getDecl(); typedef SmallVector, 64> EnumValsTy; EnumValsTy EnumVals; // Gather all enum values, set their type and sort them, // allowing easier comparison with CaseVals. for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); EDI != ED->enumerator_end(); ++EDI) { llvm::APSInt Val = EDI->getInitVal(); AdjustAPSInt(Val, CondWidth, CondIsSigned); EnumVals.push_back(std::make_pair(Val, *EDI)); } std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); EnumValsTy::iterator EIend = std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); // See which case values aren't in enum. EnumValsTy::const_iterator EI = EnumVals.begin(); for (CaseValsTy::const_iterator CI = CaseVals.begin(); CI != CaseVals.end(); CI++) { while (EI != EIend && EI->first < CI->first) EI++; if (EI == EIend || EI->first > CI->first) Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) << CondTypeBeforePromotion; } // See which of case ranges aren't in enum EI = EnumVals.begin(); for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); RI != CaseRanges.end() && EI != EIend; RI++) { while (EI != EIend && EI->first < RI->first) EI++; if (EI == EIend || EI->first != RI->first) { Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) << CondTypeBeforePromotion; } llvm::APSInt Hi = RI->second->getRHS()->EvaluateKnownConstInt(Context); AdjustAPSInt(Hi, CondWidth, CondIsSigned); while (EI != EIend && EI->first < Hi) EI++; if (EI == EIend || EI->first != Hi) Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) << CondTypeBeforePromotion; } // Check which enum vals aren't in switch CaseValsTy::const_iterator CI = CaseVals.begin(); CaseRangesTy::const_iterator RI = CaseRanges.begin(); bool hasCasesNotInSwitch = false; SmallVector UnhandledNames; for (EI = EnumVals.begin(); EI != EIend; EI++){ // Drop unneeded case values llvm::APSInt CIVal; while (CI != CaseVals.end() && CI->first < EI->first) CI++; if (CI != CaseVals.end() && CI->first == EI->first) continue; // Drop unneeded case ranges for (; RI != CaseRanges.end(); RI++) { llvm::APSInt Hi = RI->second->getRHS()->EvaluateKnownConstInt(Context); AdjustAPSInt(Hi, CondWidth, CondIsSigned); if (EI->first <= Hi) break; } if (RI == CaseRanges.end() || EI->first < RI->first) { hasCasesNotInSwitch = true; UnhandledNames.push_back(EI->second->getDeclName()); } } if (TheDefaultStmt && UnhandledNames.empty()) Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default); // Produce a nice diagnostic if multiple values aren't handled. switch (UnhandledNames.size()) { case 0: break; case 1: Diag(CondExpr->getExprLoc(), TheDefaultStmt ? diag::warn_def_missing_case1 : diag::warn_missing_case1) << UnhandledNames[0]; break; case 2: Diag(CondExpr->getExprLoc(), TheDefaultStmt ? diag::warn_def_missing_case2 : diag::warn_missing_case2) << UnhandledNames[0] << UnhandledNames[1]; break; case 3: Diag(CondExpr->getExprLoc(), TheDefaultStmt ? diag::warn_def_missing_case3 : diag::warn_missing_case3) << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; break; default: Diag(CondExpr->getExprLoc(), TheDefaultStmt ? diag::warn_def_missing_cases : diag::warn_missing_cases) << (unsigned)UnhandledNames.size() << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; break; } if (!hasCasesNotInSwitch) SS->setAllEnumCasesCovered(); } } DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), BodyStmt, diag::warn_empty_switch_body); // FIXME: If the case list was broken is some way, we don't have a good system // to patch it up. Instead, just return the whole substmt as broken. if (CaseListIsErroneous) return StmtError(); return Owned(SS); } StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, Decl *CondVar, Stmt *Body) { ExprResult CondResult(Cond.release()); VarDecl *ConditionVar = 0; if (CondVar) { ConditionVar = cast(CondVar); CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); if (CondResult.isInvalid()) return StmtError(); } Expr *ConditionExpr = CondResult.take(); if (!ConditionExpr) return StmtError(); DiagnoseUnusedExprResult(Body); if (isa(Body)) getCurCompoundScope().setHasEmptyLoopBodies(); return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, Body, WhileLoc)); } StmtResult Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, SourceLocation WhileLoc, SourceLocation CondLParen, Expr *Cond, SourceLocation CondRParen) { assert(Cond && "ActOnDoStmt(): missing expression"); ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); if (CondResult.isInvalid() || CondResult.isInvalid()) return StmtError(); Cond = CondResult.take(); CheckImplicitConversions(Cond, DoLoc); CondResult = MaybeCreateExprWithCleanups(Cond); if (CondResult.isInvalid()) return StmtError(); Cond = CondResult.take(); DiagnoseUnusedExprResult(Body); return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); } StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, Stmt *First, FullExprArg second, Decl *secondVar, FullExprArg third, SourceLocation RParenLoc, Stmt *Body) { if (!getLangOpts().CPlusPlus) { if (DeclStmt *DS = dyn_cast_or_null(First)) { // C99 6.8.5p3: The declaration part of a 'for' statement shall only // declare identifiers for objects having storage class 'auto' or // 'register'. for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); DI!=DE; ++DI) { VarDecl *VD = dyn_cast(*DI); if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) VD = 0; if (VD == 0) Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); // FIXME: mark decl erroneous! } } } ExprResult SecondResult(second.release()); VarDecl *ConditionVar = 0; if (secondVar) { ConditionVar = cast(secondVar); SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); if (SecondResult.isInvalid()) return StmtError(); } Expr *Third = third.release().takeAs(); DiagnoseUnusedExprResult(First); DiagnoseUnusedExprResult(Third); DiagnoseUnusedExprResult(Body); if (isa(Body)) getCurCompoundScope().setHasEmptyLoopBodies(); return Owned(new (Context) ForStmt(Context, First, SecondResult.take(), ConditionVar, Third, Body, ForLoc, LParenLoc, RParenLoc)); } /// In an Objective C collection iteration statement: /// for (x in y) /// x can be an arbitrary l-value expression. Bind it up as a /// full-expression. StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { // Reduce placeholder expressions here. Note that this rejects the // use of pseudo-object l-values in this position. ExprResult result = CheckPlaceholderExpr(E); if (result.isInvalid()) return StmtError(); E = result.take(); CheckImplicitConversions(E); result = MaybeCreateExprWithCleanups(E); if (result.isInvalid()) return StmtError(); return Owned(static_cast(result.take())); } ExprResult Sema::ActOnObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) { assert(collection); // Bail out early if we've got a type-dependent expression. if (collection->isTypeDependent()) return Owned(collection); // Perform normal l-value conversion. ExprResult result = DefaultFunctionArrayLvalueConversion(collection); if (result.isInvalid()) return ExprError(); collection = result.take(); // The operand needs to have object-pointer type. // TODO: should we do a contextual conversion? const ObjCObjectPointerType *pointerType = collection->getType()->getAs(); if (!pointerType) return Diag(forLoc, diag::err_collection_expr_type) << collection->getType() << collection->getSourceRange(); // Check that the operand provides // - countByEnumeratingWithState:objects:count: const ObjCObjectType *objectType = pointerType->getObjectType(); ObjCInterfaceDecl *iface = objectType->getInterface(); // If we have a forward-declared type, we can't do this check. // Under ARC, it is an error not to have a forward-declared class. if (iface && RequireCompleteType(forLoc, QualType(objectType, 0), getLangOpts().ObjCAutoRefCount ? PDiag(diag::err_arc_collection_forward) << collection->getSourceRange() : PDiag(0))) { // Otherwise, if we have any useful type information, check that // the type declares the appropriate method. } else if (iface || !objectType->qual_empty()) { IdentifierInfo *selectorIdents[] = { &Context.Idents.get("countByEnumeratingWithState"), &Context.Idents.get("objects"), &Context.Idents.get("count") }; Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]); ObjCMethodDecl *method = 0; // If there's an interface, look in both the public and private APIs. if (iface) { method = iface->lookupInstanceMethod(selector); if (!method) method = LookupPrivateInstanceMethod(selector, iface); } // Also check protocol qualifiers. if (!method) method = LookupMethodInQualifiedType(selector, pointerType, /*instance*/ true); // If we didn't find it anywhere, give up. if (!method) { Diag(forLoc, diag::warn_collection_expr_type) << collection->getType() << selector << collection->getSourceRange(); } // TODO: check for an incompatible signature? } // Wrap up any cleanups in the expression. return Owned(MaybeCreateExprWithCleanups(collection)); } StmtResult Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, SourceLocation LParenLoc, Stmt *First, Expr *Second, SourceLocation RParenLoc, Stmt *Body) { if (First) { QualType FirstType; if (DeclStmt *DS = dyn_cast(First)) { if (!DS->isSingleDecl()) return StmtError(Diag((*DS->decl_begin())->getLocation(), diag::err_toomany_element_decls)); VarDecl *D = cast(DS->getSingleDecl()); FirstType = D->getType(); // C99 6.8.5p3: The declaration part of a 'for' statement shall only // declare identifiers for objects having storage class 'auto' or // 'register'. if (!D->hasLocalStorage()) return StmtError(Diag(D->getLocation(), diag::err_non_variable_decl_in_for)); } else { Expr *FirstE = cast(First); if (!FirstE->isTypeDependent() && !FirstE->isLValue()) return StmtError(Diag(First->getLocStart(), diag::err_selector_element_not_lvalue) << First->getSourceRange()); FirstType = static_cast(First)->getType(); } if (!FirstType->isDependentType() && !FirstType->isObjCObjectPointerType() && !FirstType->isBlockPointerType()) Diag(ForLoc, diag::err_selector_element_type) << FirstType << First->getSourceRange(); } return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, ForLoc, RParenLoc)); } namespace { enum BeginEndFunction { BEF_begin, BEF_end }; /// Build a variable declaration for a for-range statement. static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, QualType Type, const char *Name) { DeclContext *DC = SemaRef.CurContext; IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, TInfo, SC_Auto, SC_None); Decl->setImplicit(); return Decl; } /// Finish building a variable declaration for a for-range statement. /// \return true if an error occurs. static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, SourceLocation Loc, int diag) { // Deduce the type for the iterator variable now rather than leaving it to // AddInitializerToDecl, so we can produce a more suitable diagnostic. TypeSourceInfo *InitTSI = 0; if ((!isa(Init) && Init->getType()->isVoidType()) || SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI) == Sema::DAR_Failed) SemaRef.Diag(Loc, diag) << Init->getType(); if (!InitTSI) { Decl->setInvalidDecl(); return true; } Decl->setTypeSourceInfo(InitTSI); Decl->setType(InitTSI->getType()); // In ARC, infer lifetime. // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if // we're doing the equivalent of fast iteration. if (SemaRef.getLangOpts().ObjCAutoRefCount && SemaRef.inferObjCARCLifetime(Decl)) Decl->setInvalidDecl(); SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, /*TypeMayContainAuto=*/false); SemaRef.FinalizeDeclaration(Decl); SemaRef.CurContext->addHiddenDecl(Decl); return false; } /// Produce a note indicating which begin/end function was implicitly called /// by a C++0x for-range statement. This is often not obvious from the code, /// nor from the diagnostics produced when analysing the implicit expressions /// required in a for-range statement. void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, BeginEndFunction BEF) { CallExpr *CE = dyn_cast(E); if (!CE) return; FunctionDecl *D = dyn_cast(CE->getCalleeDecl()); if (!D) return; SourceLocation Loc = D->getLocation(); std::string Description; bool IsTemplate = false; if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { Description = SemaRef.getTemplateArgumentBindingsText( FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); IsTemplate = true; } SemaRef.Diag(Loc, diag::note_for_range_begin_end) << BEF << IsTemplate << Description << E->getType(); } /// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the /// given LookupResult is non-empty, it is assumed to describe a member which /// will be invoked. Otherwise, the function will be found via argument /// dependent lookup. static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, SourceLocation Loc, VarDecl *Decl, BeginEndFunction BEF, const DeclarationNameInfo &NameInfo, LookupResult &MemberLookup, Expr *Range) { ExprResult CallExpr; if (!MemberLookup.empty()) { ExprResult MemberRef = SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, /*IsPtr=*/false, CXXScopeSpec(), /*TemplateKWLoc=*/SourceLocation(), /*FirstQualifierInScope=*/0, MemberLookup, /*TemplateArgs=*/0); if (MemberRef.isInvalid()) return ExprError(); CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), Loc, 0); if (CallExpr.isInvalid()) return ExprError(); } else { UnresolvedSet<0> FoundNames; // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace // std is an associated namespace. UnresolvedLookupExpr *Fn = UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, NestedNameSpecifierLoc(), NameInfo, /*NeedsADL=*/true, /*Overloaded=*/false, FoundNames.begin(), FoundNames.end(), /*LookInStdNamespace=*/true); CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 0, /*AllowTypoCorrection=*/false); if (CallExpr.isInvalid()) { SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) << Range->getType(); return ExprError(); } } if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, diag::err_for_range_iter_deduction_failure)) { NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); return ExprError(); } return CallExpr; } } /// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. /// /// C++0x [stmt.ranged]: /// A range-based for statement is equivalent to /// /// { /// auto && __range = range-init; /// for ( auto __begin = begin-expr, /// __end = end-expr; /// __begin != __end; /// ++__begin ) { /// for-range-declaration = *__begin; /// statement /// } /// } /// /// The body of the loop is not available yet, since it cannot be analysed until /// we have determined the type of the for-range-declaration. StmtResult Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, Stmt *First, SourceLocation ColonLoc, Expr *Range, SourceLocation RParenLoc) { if (!First || !Range) return StmtError(); DeclStmt *DS = dyn_cast(First); assert(DS && "first part of for range not a decl stmt"); if (!DS->isSingleDecl()) { Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); return StmtError(); } if (DS->getSingleDecl()->isInvalidDecl()) return StmtError(); if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) return StmtError(); // Build auto && __range = range-init SourceLocation RangeLoc = Range->getLocStart(); VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, Context.getAutoRRefDeductType(), "__range"); if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, diag::err_for_range_deduction_failure)) return StmtError(); // Claim the type doesn't contain auto: we've already done the checking. DeclGroupPtrTy RangeGroup = BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); if (RangeDecl.isInvalid()) return StmtError(); return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, RParenLoc); } /// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. StmtResult Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, Expr *Inc, Stmt *LoopVarDecl, SourceLocation RParenLoc) { Scope *S = getCurScope(); DeclStmt *RangeDS = cast(RangeDecl); VarDecl *RangeVar = cast(RangeDS->getSingleDecl()); QualType RangeVarType = RangeVar->getType(); DeclStmt *LoopVarDS = cast(LoopVarDecl); VarDecl *LoopVar = cast(LoopVarDS->getSingleDecl()); StmtResult BeginEndDecl = BeginEnd; ExprResult NotEqExpr = Cond, IncrExpr = Inc; if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { SourceLocation RangeLoc = RangeVar->getLocation(); const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType(); ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, VK_LValue, ColonLoc); if (BeginRangeRef.isInvalid()) return StmtError(); ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, VK_LValue, ColonLoc); if (EndRangeRef.isInvalid()) return StmtError(); QualType AutoType = Context.getAutoDeductType(); Expr *Range = RangeVar->getInit(); if (!Range) return StmtError(); QualType RangeType = Range->getType(); if (RequireCompleteType(RangeLoc, RangeType, PDiag(diag::err_for_range_incomplete_type))) return StmtError(); // Build auto __begin = begin-expr, __end = end-expr. VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, "__begin"); VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, "__end"); // Build begin-expr and end-expr and attach to __begin and __end variables. ExprResult BeginExpr, EndExpr; if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { // - if _RangeT is an array type, begin-expr and end-expr are __range and // __range + __bound, respectively, where __bound is the array bound. If // _RangeT is an array of unknown size or an array of incomplete type, // the program is ill-formed; // begin-expr is __range. BeginExpr = BeginRangeRef; if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc, diag::err_for_range_iter_deduction_failure)) { NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); return StmtError(); } // Find the array bound. ExprResult BoundExpr; if (const ConstantArrayType *CAT = dyn_cast(UnqAT)) BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), Context.getPointerDiffType(), RangeLoc)); else if (const VariableArrayType *VAT = dyn_cast(UnqAT)) BoundExpr = VAT->getSizeExpr(); else { // Can't be a DependentSizedArrayType or an IncompleteArrayType since // UnqAT is not incomplete and Range is not type-dependent. llvm_unreachable("Unexpected array type in for-range"); } // end-expr is __range + __bound. EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(), BoundExpr.get()); if (EndExpr.isInvalid()) return StmtError(); if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, diag::err_for_range_iter_deduction_failure)) { NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); return StmtError(); } } else { DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), ColonLoc); DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), ColonLoc); LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { // - if _RangeT is a class type, the unqualified-ids begin and end are // looked up in the scope of class _RangeT as if by class member access // lookup (3.4.5), and if either (or both) finds at least one // declaration, begin-expr and end-expr are __range.begin() and // __range.end(), respectively; LookupQualifiedName(BeginMemberLookup, D); LookupQualifiedName(EndMemberLookup, D); if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) << RangeType << BeginMemberLookup.empty(); return StmtError(); } } else { // - otherwise, begin-expr and end-expr are begin(__range) and // end(__range), respectively, where begin and end are looked up with // argument-dependent lookup (3.4.2). For the purposes of this name // lookup, namespace std is an associated namespace. } BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, BEF_begin, BeginNameInfo, BeginMemberLookup, BeginRangeRef.get()); if (BeginExpr.isInvalid()) return StmtError(); EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, BEF_end, EndNameInfo, EndMemberLookup, EndRangeRef.get()); if (EndExpr.isInvalid()) return StmtError(); } // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); if (!Context.hasSameType(BeginType, EndType)) { Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) << BeginType << EndType; NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); } Decl *BeginEndDecls[] = { BeginVar, EndVar }; // Claim the type doesn't contain auto: we've already done the checking. DeclGroupPtrTy BeginEndGroup = BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); const QualType BeginRefNonRefType = BeginType.getNonReferenceType(); ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, VK_LValue, ColonLoc); if (BeginRef.isInvalid()) return StmtError(); ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), VK_LValue, ColonLoc); if (EndRef.isInvalid()) return StmtError(); // Build and check __begin != __end expression. NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, BeginRef.get(), EndRef.get()); NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); if (NotEqExpr.isInvalid()) { NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); if (!Context.hasSameType(BeginType, EndType)) NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); return StmtError(); } // Build and check ++__begin expression. BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, VK_LValue, ColonLoc); if (BeginRef.isInvalid()) return StmtError(); IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); if (IncrExpr.isInvalid()) { NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); return StmtError(); } // Build and check *__begin expression. BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, VK_LValue, ColonLoc); if (BeginRef.isInvalid()) return StmtError(); ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); if (DerefExpr.isInvalid()) { NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); return StmtError(); } // Attach *__begin as initializer for VD. if (!LoopVar->isInvalidDecl()) { AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, /*TypeMayContainAuto=*/true); if (LoopVar->isInvalidDecl()) NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); } } else { // The range is implicitly used as a placeholder when it is dependent. RangeVar->setUsed(); } return Owned(new (Context) CXXForRangeStmt(RangeDS, cast_or_null(BeginEndDecl.get()), NotEqExpr.take(), IncrExpr.take(), LoopVarDS, /*Body=*/0, ForLoc, ColonLoc, RParenLoc)); } /// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. /// This is a separate step from ActOnCXXForRangeStmt because analysis of the /// body cannot be performed until after the type of the range variable is /// determined. StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { if (!S || !B) return StmtError(); CXXForRangeStmt *ForStmt = cast(S); ForStmt->setBody(B); DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B, diag::warn_empty_range_based_for_body); return S; } StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, LabelDecl *TheDecl) { getCurFunction()->setHasBranchIntoScope(); TheDecl->setUsed(); return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); } StmtResult Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, Expr *E) { // Convert operand to void* if (!E->isTypeDependent()) { QualType ETy = E->getType(); QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); ExprResult ExprRes = Owned(E); AssignConvertType ConvTy = CheckSingleAssignmentConstraints(DestTy, ExprRes); if (ExprRes.isInvalid()) return StmtError(); E = ExprRes.take(); if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) return StmtError(); E = MaybeCreateExprWithCleanups(E); } getCurFunction()->setHasIndirectGoto(); return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); } StmtResult Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { Scope *S = CurScope->getContinueParent(); if (!S) { // C99 6.8.6.2p1: A break shall appear only in or as a loop body. return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); } return Owned(new (Context) ContinueStmt(ContinueLoc)); } StmtResult Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { Scope *S = CurScope->getBreakParent(); if (!S) { // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); } return Owned(new (Context) BreakStmt(BreakLoc)); } /// \brief Determine whether the given expression is a candidate for /// copy elision in either a return statement or a throw expression. /// /// \param ReturnType If we're determining the copy elision candidate for /// a return statement, this is the return type of the function. If we're /// determining the copy elision candidate for a throw expression, this will /// be a NULL type. /// /// \param E The expression being returned from the function or block, or /// being thrown. /// /// \param AllowFunctionParameter Whether we allow function parameters to /// be considered NRVO candidates. C++ prohibits this for NRVO itself, but /// we re-use this logic to determine whether we should try to move as part of /// a return or throw (which does allow function parameters). /// /// \returns The NRVO candidate variable, if the return statement may use the /// NRVO, or NULL if there is no such candidate. const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, Expr *E, bool AllowFunctionParameter) { QualType ExprType = E->getType(); // - in a return statement in a function with ... // ... a class return type ... if (!ReturnType.isNull()) { if (!ReturnType->isRecordType()) return 0; // ... the same cv-unqualified type as the function return type ... if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) return 0; } // ... the expression is the name of a non-volatile automatic object // (other than a function or catch-clause parameter)) ... const DeclRefExpr *DR = dyn_cast(E->IgnoreParens()); if (!DR) return 0; const VarDecl *VD = dyn_cast(DR->getDecl()); if (!VD) return 0; // ...object (other than a function or catch-clause parameter)... if (VD->getKind() != Decl::Var && !(AllowFunctionParameter && VD->getKind() == Decl::ParmVar)) return 0; if (VD->isExceptionVariable()) return 0; // ...automatic... if (!VD->hasLocalStorage()) return 0; // ...non-volatile... if (VD->getType().isVolatileQualified()) return 0; if (VD->getType()->isReferenceType()) return 0; // __block variables can't be allocated in a way that permits NRVO. if (VD->hasAttr()) return 0; // Variables with higher required alignment than their type's ABI // alignment cannot use NRVO. if (VD->hasAttr() && Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType())) return 0; return VD; } /// \brief Perform the initialization of a potentially-movable value, which /// is the result of return value. /// /// This routine implements C++0x [class.copy]p33, which attempts to treat /// returned lvalues as rvalues in certain cases (to prefer move construction), /// then falls back to treating them as lvalues if that failed. ExprResult Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, const VarDecl *NRVOCandidate, QualType ResultType, Expr *Value, bool AllowNRVO) { // C++0x [class.copy]p33: // When the criteria for elision of a copy operation are met or would // be met save for the fact that the source object is a function // parameter, and the object to be copied is designated by an lvalue, // overload resolution to select the constructor for the copy is first // performed as if the object were designated by an rvalue. ExprResult Res = ExprError(); if (AllowNRVO && (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) { ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, Value->getType(), CK_LValueToRValue, Value, VK_XValue); Expr *InitExpr = &AsRvalue; InitializationKind Kind = InitializationKind::CreateCopy(Value->getLocStart(), Value->getLocStart()); InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); // [...] If overload resolution fails, or if the type of the first // parameter of the selected constructor is not an rvalue reference // to the object's type (possibly cv-qualified), overload resolution // is performed again, considering the object as an lvalue. if (Seq) { for (InitializationSequence::step_iterator Step = Seq.step_begin(), StepEnd = Seq.step_end(); Step != StepEnd; ++Step) { if (Step->Kind != InitializationSequence::SK_ConstructorInitialization) continue; CXXConstructorDecl *Constructor = cast(Step->Function.Function); const RValueReferenceType *RRefType = Constructor->getParamDecl(0)->getType() ->getAs(); // If we don't meet the criteria, break out now. if (!RRefType || !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), Context.getTypeDeclType(Constructor->getParent()))) break; // Promote "AsRvalue" to the heap, since we now need this // expression node to persist. Value = ImplicitCastExpr::Create(Context, Value->getType(), CK_LValueToRValue, Value, 0, VK_XValue); // Complete type-checking the initialization of the return type // using the constructor we found. Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); } } } // Either we didn't meet the criteria for treating an lvalue as an rvalue, // above, or overload resolution failed. Either way, we need to try // (again) now with the return value expression as written. if (Res.isInvalid()) Res = PerformCopyInitialization(Entity, SourceLocation(), Value); return Res; } /// ActOnCapScopeReturnStmt - Utility routine to type-check return statements /// for capturing scopes. /// StmtResult Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { // If this is the first return we've seen, infer the return type. // [expr.prim.lambda]p4 in C++11; block literals follow a superset of those // rules which allows multiple return statements. CapturingScopeInfo *CurCap = cast(getCurFunction()); if (CurCap->HasImplicitReturnType) { QualType ReturnT; if (RetValExp && !isa(RetValExp)) { ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); if (Result.isInvalid()) return StmtError(); RetValExp = Result.take(); if (!RetValExp->isTypeDependent()) ReturnT = RetValExp->getType(); else ReturnT = Context.DependentTy; } else { if (RetValExp) { // C++11 [expr.lambda.prim]p4 bans inferring the result from an // initializer list, because it is not an expression (even // though we represent it as one). We still deduce 'void'. Diag(ReturnLoc, diag::err_lambda_return_init_list) << RetValExp->getSourceRange(); } ReturnT = Context.VoidTy; } // We require the return types to strictly match here. if (!CurCap->ReturnType.isNull() && !CurCap->ReturnType->isDependentType() && !ReturnT->isDependentType() && !Context.hasSameType(ReturnT, CurCap->ReturnType)) { Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible) << ReturnT << CurCap->ReturnType << (getCurLambda() != 0); return StmtError(); } CurCap->ReturnType = ReturnT; } QualType FnRetType = CurCap->ReturnType; assert(!FnRetType.isNull()); if (BlockScopeInfo *CurBlock = dyn_cast(CurCap)) { if (CurBlock->FunctionType->getAs()->getNoReturnAttr()) { Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr); return StmtError(); } } else { LambdaScopeInfo *LSI = cast(CurCap); if (LSI->CallOperator->getType()->getAs()->getNoReturnAttr()){ Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr); return StmtError(); } } // Otherwise, verify that this result type matches the previous one. We are // pickier with blocks than for normal functions because we don't have GCC // compatibility to worry about here. const VarDecl *NRVOCandidate = 0; if (FnRetType->isDependentType()) { // Delay processing for now. TODO: there are lots of dependent // types we can conclusively prove aren't void. } else if (FnRetType->isVoidType()) { if (RetValExp && !isa(RetValExp) && !(getLangOpts().CPlusPlus && (RetValExp->isTypeDependent() || RetValExp->getType()->isVoidType()))) { if (!getLangOpts().CPlusPlus && RetValExp->getType()->isVoidType()) Diag(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2; else { Diag(ReturnLoc, diag::err_return_block_has_expr); RetValExp = 0; } } } else if (!RetValExp) { return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); } else if (!RetValExp->isTypeDependent()) { // we have a non-void block with an expression, continue checking // C99 6.8.6.4p3(136): The return statement is not an assignment. The // overlap restriction of subclause 6.5.16.1 does not apply to the case of // function return. // In C++ the return statement is handled via a copy initialization. // the C version of which boils down to CheckSingleAssignmentConstraints. NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, FnRetType, NRVOCandidate != 0); ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, FnRetType, RetValExp); if (Res.isInvalid()) { // FIXME: Cleanup temporaries here, anyway? return StmtError(); } RetValExp = Res.take(); CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); } if (RetValExp) { CheckImplicitConversions(RetValExp, ReturnLoc); RetValExp = MaybeCreateExprWithCleanups(RetValExp); } ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); // If we need to check for the named return value optimization, save the // return statement in our scope for later processing. if (getLangOpts().CPlusPlus && FnRetType->isRecordType() && !CurContext->isDependentContext()) FunctionScopes.back()->Returns.push_back(Result); return Owned(Result); } StmtResult Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { // Check for unexpanded parameter packs. if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp)) return StmtError(); if (isa(getCurFunction())) return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp); QualType FnRetType; QualType RelatedRetType; if (const FunctionDecl *FD = getCurFunctionDecl()) { FnRetType = FD->getResultType(); if (FD->hasAttr() || FD->getType()->getAs()->getNoReturnAttr()) Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) << FD->getDeclName(); } else if (ObjCMethodDecl *MD = getCurMethodDecl()) { FnRetType = MD->getResultType(); if (MD->hasRelatedResultType() && MD->getClassInterface()) { // In the implementation of a method with a related return type, the // type used to type-check the validity of return statements within the // method body is a pointer to the type of the class being implemented. RelatedRetType = Context.getObjCInterfaceType(MD->getClassInterface()); RelatedRetType = Context.getObjCObjectPointerType(RelatedRetType); } } else // If we don't have a function/method context, bail. return StmtError(); ReturnStmt *Result = 0; if (FnRetType->isVoidType()) { if (RetValExp) { if (isa(RetValExp)) { // We simply never allow init lists as the return value of void // functions. This is compatible because this was never allowed before, // so there's no legacy code to deal with. NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); int FunctionKind = 0; if (isa(CurDecl)) FunctionKind = 1; else if (isa(CurDecl)) FunctionKind = 2; else if (isa(CurDecl)) FunctionKind = 3; Diag(ReturnLoc, diag::err_return_init_list) << CurDecl->getDeclName() << FunctionKind << RetValExp->getSourceRange(); // Drop the expression. RetValExp = 0; } else if (!RetValExp->isTypeDependent()) { // C99 6.8.6.4p1 (ext_ since GCC warns) unsigned D = diag::ext_return_has_expr; if (RetValExp->getType()->isVoidType()) D = diag::ext_return_has_void_expr; else { ExprResult Result = Owned(RetValExp); Result = IgnoredValueConversions(Result.take()); if (Result.isInvalid()) return StmtError(); RetValExp = Result.take(); RetValExp = ImpCastExprToType(RetValExp, Context.VoidTy, CK_ToVoid).take(); } // return (some void expression); is legal in C++. if (D != diag::ext_return_has_void_expr || !getLangOpts().CPlusPlus) { NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); int FunctionKind = 0; if (isa(CurDecl)) FunctionKind = 1; else if (isa(CurDecl)) FunctionKind = 2; else if (isa(CurDecl)) FunctionKind = 3; Diag(ReturnLoc, D) << CurDecl->getDeclName() << FunctionKind << RetValExp->getSourceRange(); } } if (RetValExp) { CheckImplicitConversions(RetValExp, ReturnLoc); RetValExp = MaybeCreateExprWithCleanups(RetValExp); } } Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); } else if (!RetValExp && !FnRetType->isDependentType()) { unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 // C99 6.8.6.4p1 (ext_ since GCC warns) if (getLangOpts().C99) DiagID = diag::ext_return_missing_expr; if (FunctionDecl *FD = getCurFunctionDecl()) Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; else Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; Result = new (Context) ReturnStmt(ReturnLoc); } else { const VarDecl *NRVOCandidate = 0; if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { // we have a non-void function with an expression, continue checking if (!RelatedRetType.isNull()) { // If we have a related result type, perform an extra conversion here. // FIXME: The diagnostics here don't really describe what is happening. InitializedEntity Entity = InitializedEntity::InitializeTemporary(RelatedRetType); ExprResult Res = PerformCopyInitialization(Entity, SourceLocation(), RetValExp); if (Res.isInvalid()) { // FIXME: Cleanup temporaries here, anyway? return StmtError(); } RetValExp = Res.takeAs(); } // C99 6.8.6.4p3(136): The return statement is not an assignment. The // overlap restriction of subclause 6.5.16.1 does not apply to the case of // function return. // In C++ the return statement is handled via a copy initialization, // the C version of which boils down to CheckSingleAssignmentConstraints. NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, FnRetType, NRVOCandidate != 0); ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, FnRetType, RetValExp); if (Res.isInvalid()) { // FIXME: Cleanup temporaries here, anyway? return StmtError(); } RetValExp = Res.takeAs(); if (RetValExp) CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); } if (RetValExp) { CheckImplicitConversions(RetValExp, ReturnLoc); RetValExp = MaybeCreateExprWithCleanups(RetValExp); } Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); } // If we need to check for the named return value optimization, save the // return statement in our scope for later processing. if (getLangOpts().CPlusPlus && FnRetType->isRecordType() && !CurContext->isDependentContext()) FunctionScopes.back()->Returns.push_back(Result); return Owned(Result); } /// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently /// ignore "noop" casts in places where an lvalue is required by an inline asm. /// We emulate this behavior when -fheinous-gnu-extensions is specified, but /// provide a strong guidance to not use it. /// /// This method checks to see if the argument is an acceptable l-value and /// returns false if it is a case we can handle. static bool CheckAsmLValue(const Expr *E, Sema &S) { // Type dependent expressions will be checked during instantiation. if (E->isTypeDependent()) return false; if (E->isLValue()) return false; // Cool, this is an lvalue. // Okay, this is not an lvalue, but perhaps it is the result of a cast that we // are supposed to allow. const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); if (E != E2 && E2->isLValue()) { if (!S.getLangOpts().HeinousExtensions) S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) << E->getSourceRange(); else S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) << E->getSourceRange(); // Accept, even if we emitted an error diagnostic. return false; } // None of the above, just randomly invalid non-lvalue. return true; } /// isOperandMentioned - Return true if the specified operand # is mentioned /// anywhere in the decomposed asm string. static bool isOperandMentioned(unsigned OpNo, ArrayRef AsmStrPieces) { for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; if (!Piece.isOperand()) continue; // If this is a reference to the input and if the input was the smaller // one, then we have to reject this asm. if (Piece.getOperandNo() == OpNo) return true; } return false; } StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, bool IsVolatile, unsigned NumOutputs, unsigned NumInputs, IdentifierInfo **Names, MultiExprArg constraints, MultiExprArg exprs, Expr *asmString, MultiExprArg clobbers, SourceLocation RParenLoc, bool MSAsm) { unsigned NumClobbers = clobbers.size(); StringLiteral **Constraints = reinterpret_cast(constraints.get()); Expr **Exprs = exprs.get(); StringLiteral *AsmString = cast(asmString); StringLiteral **Clobbers = reinterpret_cast(clobbers.get()); SmallVector OutputConstraintInfos; // The parser verifies that there is a string literal here. if (!AsmString->isAscii()) return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) << AsmString->getSourceRange()); for (unsigned i = 0; i != NumOutputs; i++) { StringLiteral *Literal = Constraints[i]; if (!Literal->isAscii()) return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) << Literal->getSourceRange()); StringRef OutputName; if (Names[i]) OutputName = Names[i]->getName(); TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); if (!Context.getTargetInfo().validateOutputConstraint(Info)) return StmtError(Diag(Literal->getLocStart(), diag::err_asm_invalid_output_constraint) << Info.getConstraintStr()); // Check that the output exprs are valid lvalues. Expr *OutputExpr = Exprs[i]; if (CheckAsmLValue(OutputExpr, *this)) { return StmtError(Diag(OutputExpr->getLocStart(), diag::err_asm_invalid_lvalue_in_output) << OutputExpr->getSourceRange()); } OutputConstraintInfos.push_back(Info); } SmallVector InputConstraintInfos; for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { StringLiteral *Literal = Constraints[i]; if (!Literal->isAscii()) return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) << Literal->getSourceRange()); StringRef InputName; if (Names[i]) InputName = Names[i]->getName(); TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(), NumOutputs, Info)) { return StmtError(Diag(Literal->getLocStart(), diag::err_asm_invalid_input_constraint) << Info.getConstraintStr()); } Expr *InputExpr = Exprs[i]; // Only allow void types for memory constraints. if (Info.allowsMemory() && !Info.allowsRegister()) { if (CheckAsmLValue(InputExpr, *this)) return StmtError(Diag(InputExpr->getLocStart(), diag::err_asm_invalid_lvalue_in_input) << Info.getConstraintStr() << InputExpr->getSourceRange()); } if (Info.allowsRegister()) { if (InputExpr->getType()->isVoidType()) { return StmtError(Diag(InputExpr->getLocStart(), diag::err_asm_invalid_type_in_input) << InputExpr->getType() << Info.getConstraintStr() << InputExpr->getSourceRange()); } } ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); if (Result.isInvalid()) return StmtError(); Exprs[i] = Result.take(); InputConstraintInfos.push_back(Info); } // Check that the clobbers are valid. for (unsigned i = 0; i != NumClobbers; i++) { StringLiteral *Literal = Clobbers[i]; if (!Literal->isAscii()) return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) << Literal->getSourceRange()); StringRef Clobber = Literal->getString(); if (!Context.getTargetInfo().isValidClobber(Clobber)) return StmtError(Diag(Literal->getLocStart(), diag::err_asm_unknown_register_name) << Clobber); } AsmStmt *NS = new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, NumOutputs, NumInputs, Names, Constraints, Exprs, AsmString, NumClobbers, Clobbers, RParenLoc); // Validate the asm string, ensuring it makes sense given the operands we // have. SmallVector Pieces; unsigned DiagOffs; if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) << AsmString->getSourceRange(); return StmtError(); } // Validate tied input operands for type mismatches. for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; // If this is a tied constraint, verify that the output and input have // either exactly the same type, or that they are int/ptr operands with the // same size (int/long, int*/long, are ok etc). if (!Info.hasTiedOperand()) continue; unsigned TiedTo = Info.getTiedOperand(); unsigned InputOpNo = i+NumOutputs; Expr *OutputExpr = Exprs[TiedTo]; Expr *InputExpr = Exprs[InputOpNo]; if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent()) continue; QualType InTy = InputExpr->getType(); QualType OutTy = OutputExpr->getType(); if (Context.hasSameType(InTy, OutTy)) continue; // All types can be tied to themselves. // Decide if the input and output are in the same domain (integer/ptr or // floating point. enum AsmDomain { AD_Int, AD_FP, AD_Other } InputDomain, OutputDomain; if (InTy->isIntegerType() || InTy->isPointerType()) InputDomain = AD_Int; else if (InTy->isRealFloatingType()) InputDomain = AD_FP; else InputDomain = AD_Other; if (OutTy->isIntegerType() || OutTy->isPointerType()) OutputDomain = AD_Int; else if (OutTy->isRealFloatingType()) OutputDomain = AD_FP; else OutputDomain = AD_Other; // They are ok if they are the same size and in the same domain. This // allows tying things like: // void* to int* // void* to int if they are the same size. // double to long double if they are the same size. // uint64_t OutSize = Context.getTypeSize(OutTy); uint64_t InSize = Context.getTypeSize(InTy); if (OutSize == InSize && InputDomain == OutputDomain && InputDomain != AD_Other) continue; // If the smaller input/output operand is not mentioned in the asm string, // then we can promote the smaller one to a larger input and the asm string // won't notice. bool SmallerValueMentioned = false; // If this is a reference to the input and if the input was the smaller // one, then we have to reject this asm. if (isOperandMentioned(InputOpNo, Pieces)) { // This is a use in the asm string of the smaller operand. Since we // codegen this by promoting to a wider value, the asm will get printed // "wrong". SmallerValueMentioned |= InSize < OutSize; } if (isOperandMentioned(TiedTo, Pieces)) { // If this is a reference to the output, and if the output is the larger // value, then it's ok because we'll promote the input to the larger type. SmallerValueMentioned |= OutSize < InSize; } // If the smaller value wasn't mentioned in the asm string, and if the // output was a register, just extend the shorter one to the size of the // larger one. if (!SmallerValueMentioned && InputDomain != AD_Other && OutputConstraintInfos[TiedTo].allowsRegister()) continue; // Either both of the operands were mentioned or the smaller one was // mentioned. One more special case that we'll allow: if the tied input is // integer, unmentioned, and is a constant, then we'll allow truncating it // down to the size of the destination. if (InputDomain == AD_Int && OutputDomain == AD_Int && !isOperandMentioned(InputOpNo, Pieces) && InputExpr->isEvaluatable(Context)) { CastKind castKind = (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take(); Exprs[InputOpNo] = InputExpr; NS->setInputExpr(i, InputExpr); continue; } Diag(InputExpr->getLocStart(), diag::err_asm_tying_incompatible_types) << InTy << OutTy << OutputExpr->getSourceRange() << InputExpr->getSourceRange(); return StmtError(); } return Owned(NS); } StmtResult Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, SourceLocation RParen, Decl *Parm, Stmt *Body) { VarDecl *Var = cast_or_null(Parm); if (Var && Var->isInvalidDecl()) return StmtError(); return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); } StmtResult Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); } StmtResult Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, MultiStmtArg CatchStmts, Stmt *Finally) { if (!getLangOpts().ObjCExceptions) Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; getCurFunction()->setHasBranchProtectedScope(); unsigned NumCatchStmts = CatchStmts.size(); return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, CatchStmts.release(), NumCatchStmts, Finally)); } StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw) { if (Throw) { Throw = MaybeCreateExprWithCleanups(Throw); ExprResult Result = DefaultLvalueConversion(Throw); if (Result.isInvalid()) return StmtError(); Throw = Result.take(); QualType ThrowType = Throw->getType(); // Make sure the expression type is an ObjC pointer or "void *". if (!ThrowType->isDependentType() && !ThrowType->isObjCObjectPointerType()) { const PointerType *PT = ThrowType->getAs(); if (!PT || !PT->getPointeeType()->isVoidType()) return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) << Throw->getType() << Throw->getSourceRange()); } } return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); } StmtResult Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, Scope *CurScope) { if (!getLangOpts().ObjCExceptions) Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; if (!Throw) { // @throw without an expression designates a rethrow (which much occur // in the context of an @catch clause). Scope *AtCatchParent = CurScope; while (AtCatchParent && !AtCatchParent->isAtCatchScope()) AtCatchParent = AtCatchParent->getParent(); if (!AtCatchParent) return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); } return BuildObjCAtThrowStmt(AtLoc, Throw); } ExprResult Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) { ExprResult result = DefaultLvalueConversion(operand); if (result.isInvalid()) return ExprError(); operand = result.take(); // Make sure the expression type is an ObjC pointer or "void *". QualType type = operand->getType(); if (!type->isDependentType() && !type->isObjCObjectPointerType()) { const PointerType *pointerType = type->getAs(); if (!pointerType || !pointerType->getPointeeType()->isVoidType()) return Diag(atLoc, diag::error_objc_synchronized_expects_object) << type << operand->getSourceRange(); } // The operand to @synchronized is a full-expression. return MaybeCreateExprWithCleanups(operand); } StmtResult Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, Stmt *SyncBody) { // We can't jump into or indirect-jump out of a @synchronized block. getCurFunction()->setHasBranchProtectedScope(); return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); } /// ActOnCXXCatchBlock - Takes an exception declaration and a handler block /// and creates a proper catch handler from them. StmtResult Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, Stmt *HandlerBlock) { // There's nothing to test that ActOnExceptionDecl didn't already test. return Owned(new (Context) CXXCatchStmt(CatchLoc, cast_or_null(ExDecl), HandlerBlock)); } StmtResult Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) { getCurFunction()->setHasBranchProtectedScope(); return Owned(new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body)); } namespace { class TypeWithHandler { QualType t; CXXCatchStmt *stmt; public: TypeWithHandler(const QualType &type, CXXCatchStmt *statement) : t(type), stmt(statement) {} // An arbitrary order is fine as long as it places identical // types next to each other. bool operator<(const TypeWithHandler &y) const { if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) return true; if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) return false; else return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); } bool operator==(const TypeWithHandler& other) const { return t == other.t; } CXXCatchStmt *getCatchStmt() const { return stmt; } SourceLocation getTypeSpecStartLoc() const { return stmt->getExceptionDecl()->getTypeSpecStartLoc(); } }; } /// ActOnCXXTryBlock - Takes a try compound-statement and a number of /// handlers and creates a try statement from them. StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, MultiStmtArg RawHandlers) { // Don't report an error if 'try' is used in system headers. if (!getLangOpts().CXXExceptions && !getSourceManager().isInSystemHeader(TryLoc)) Diag(TryLoc, diag::err_exceptions_disabled) << "try"; unsigned NumHandlers = RawHandlers.size(); assert(NumHandlers > 0 && "The parser shouldn't call this if there are no handlers."); Stmt **Handlers = RawHandlers.get(); SmallVector TypesWithHandlers; for (unsigned i = 0; i < NumHandlers; ++i) { CXXCatchStmt *Handler = cast(Handlers[i]); if (!Handler->getExceptionDecl()) { if (i < NumHandlers - 1) return StmtError(Diag(Handler->getLocStart(), diag::err_early_catch_all)); continue; } const QualType CaughtType = Handler->getCaughtType(); const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); } // Detect handlers for the same type as an earlier one. if (NumHandlers > 1) { llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); TypeWithHandler prev = TypesWithHandlers[0]; for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { TypeWithHandler curr = TypesWithHandlers[i]; if (curr == prev) { Diag(curr.getTypeSpecStartLoc(), diag::warn_exception_caught_by_earlier_handler) << curr.getCatchStmt()->getCaughtType().getAsString(); Diag(prev.getTypeSpecStartLoc(), diag::note_previous_exception_handler) << prev.getCatchStmt()->getCaughtType().getAsString(); } prev = curr; } } getCurFunction()->setHasBranchProtectedScope(); // FIXME: We should detect handlers that cannot catch anything because an // earlier handler catches a superclass. Need to find a method that is not // quadratic for this. // Neither of these are explicitly forbidden, but every compiler detects them // and warns. return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, Handlers, NumHandlers)); } StmtResult Sema::ActOnSEHTryBlock(bool IsCXXTry, SourceLocation TryLoc, Stmt *TryBlock, Stmt *Handler) { assert(TryBlock && Handler); getCurFunction()->setHasBranchProtectedScope(); return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler)); } StmtResult Sema::ActOnSEHExceptBlock(SourceLocation Loc, Expr *FilterExpr, Stmt *Block) { assert(FilterExpr && Block); if(!FilterExpr->getType()->isIntegerType()) { return StmtError(Diag(FilterExpr->getExprLoc(), diag::err_filter_expression_integral) << FilterExpr->getType()); } return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block)); } StmtResult Sema::ActOnSEHFinallyBlock(SourceLocation Loc, Stmt *Block) { assert(Block); return Owned(SEHFinallyStmt::Create(Context,Loc,Block)); } StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc, bool IsIfExists, NestedNameSpecifierLoc QualifierLoc, DeclarationNameInfo NameInfo, Stmt *Nested) { return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists, QualifierLoc, NameInfo, cast(Nested)); } StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc, bool IsIfExists, CXXScopeSpec &SS, UnqualifiedId &Name, Stmt *Nested) { return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists, SS.getWithLocInContext(Context), GetNameFromUnqualifiedId(Name), Nested); }