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Diffstat (limited to 'contrib/llvm/tools/clang/lib/Sema/SemaStmt.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/Sema/SemaStmt.cpp | 1806 |
1 files changed, 1806 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/Sema/SemaStmt.cpp b/contrib/llvm/tools/clang/lib/Sema/SemaStmt.cpp new file mode 100644 index 0000000..e995e8f --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Sema/SemaStmt.cpp @@ -0,0 +1,1806 @@ +//===--- 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/AST/APValue.h" +#include "clang/AST/ASTContext.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/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<Stmt*>(E)); +} + + +StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, bool LeadingEmptyMacro) { + return Owned(new (Context) NullStmt(SemiLoc, LeadingEmptyMacro)); +} + +StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, + SourceLocation EndLoc) { + DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); + + // 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<DeclGroupRef>(); + + // If we have an invalid decl, just return. + if (DG.isNull() || !DG.isSingleDecl()) return; + // suppress any potential 'unused variable' warning. + DG.getSingleDecl()->setUsed(); +} + +void Sema::DiagnoseUnusedExprResult(const Stmt *S) { + if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) + return DiagnoseUnusedExprResult(Label->getSubStmt()); + + const Expr *E = dyn_cast_or_null<Expr>(S); + if (!E) + return; + + if (E->isBoundMemberFunction(Context)) { + Diag(E->getLocStart(), diag::err_invalid_use_of_bound_member_func) + << E->getSourceRange(); + return; + } + + SourceLocation Loc; + SourceRange R1, R2; + if (!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<ExprWithCleanups>(E)) + E = Temps->getSubExpr(); + + E = E->IgnoreParenImpCasts(); + if (const CallExpr *CE = dyn_cast<CallExpr>(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<WarnUnusedResultAttr>()) { + Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; + return; + } + if (FD->getAttr<PureAttr>()) { + Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; + return; + } + if (FD->getAttr<ConstAttr>()) { + Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; + return; + } + } + } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { + const ObjCMethodDecl *MD = ME->getMethodDecl(); + if (MD && MD->getAttr<WarnUnusedResultAttr>()) { + Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; + return; + } + } else if (isa<ObjCPropertyRefExpr>(E)) { + DiagID = diag::warn_unused_property_expr; + } else if (const CXXFunctionalCastExpr *FC + = dyn_cast<CXXFunctionalCastExpr>(E)) { + if (isa<CXXConstructExpr>(FC->getSubExpr()) || + isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) + return; + } + // Diagnose "(void*) blah" as a typo for "(void) blah". + else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(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<PointerTypeLoc>(TI->getTypeLoc()); + + Diag(Loc, diag::warn_unused_voidptr) + << FixItHint::CreateRemoval(TL.getStarLoc()); + return; + } + } + + DiagRuntimeBehavior(Loc, PDiag(DiagID) << R1 << R2); +} + +StmtResult +Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, + MultiStmtArg elts, bool isStmtExpr) { + unsigned NumElts = elts.size(); + Stmt **Elts = reinterpret_cast<Stmt**>(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 (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { + // Note that __extension__ can be around a decl. + unsigned i = 0; + // Skip over all declarations. + for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) + /*empty*/; + + // We found the end of the list or a statement. Scan for another declstmt. + for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) + /*empty*/; + + if (i != NumElts) { + Decl *D = *cast<DeclStmt>(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]); + } + + 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"); + + // C99 6.8.4.2p3: The expression shall be an integer constant. + // However, GCC allows any evaluatable integer expression. + if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && + VerifyIntegerConstantExpression(LHSVal)) + return StmtError(); + + // GCC extension: The expression shall be an integer constant. + + if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && + VerifyIntegerConstantExpression(RHSVal)) { + RHSVal = 0; // Recover by just forgetting about it. + } + + if (getCurFunction()->SwitchStack.empty()) { + Diag(CaseLoc, diag::err_case_not_in_switch); + return StmtError(); + } + + 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) { + CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); + CS->setSubStmt(SubStmt); +} + +StmtResult +Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, + Stmt *SubStmt, Scope *CurScope) { + 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. + TheDecl->setLocation(IdentLoc); + + LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); + TheDecl->setStmt(LS); + TheDecl->setLocation(IdentLoc); + 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<VarDecl>(CondVar); + CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); + if (CondResult.isInvalid()) + return StmtError(); + } + Expr *ConditionExpr = CondResult.takeAs<Expr>(); + if (!ConditionExpr) + return StmtError(); + + DiagnoseUnusedExprResult(thenStmt); + + // Warn if the if block has a null body without an else value. + // this helps prevent bugs due to typos, such as + // if (condition); + // do_stuff(); + // + if (!elseStmt) { + if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) + // But do not warn if the body is a macro that expands to nothing, e.g: + // + // #define CALL(x) + // if (condition) + // CALL(0); + // + if (!stmt->hasLeadingEmptyMacro()) + Diag(stmt->getSemiLoc(), 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<llvm::APSInt, CaseStmt*> &LHS, + const llvm::APSInt &RHS) { + return LHS.first < RHS; + } + bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, + const std::pair<llvm::APSInt, CaseStmt*> &RHS) { + return LHS.first < RHS.first; + } + bool operator()(const llvm::APSInt &LHS, + const std::pair<llvm::APSInt, CaseStmt*> &RHS) { + return LHS < RHS.first; + } + }; +} + +/// CmpCaseVals - Comparison predicate for sorting case values. +/// +static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, + const std::pair<llvm::APSInt, CaseStmt*>& 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<llvm::APSInt, EnumConstantDecl*>& lhs, + const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) +{ + return lhs.first < rhs.first; +} + +/// EqEnumVals - Comparison preficate for uniqing enumeration values. +/// +static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, + const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) +{ + return lhs.first == rhs.first; +} + +/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of +/// potentially integral-promoted expression @p expr. +static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { + if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) { + const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); + QualType TypeBeforePromotion = ExprBeforePromotion->getType(); + if (TypeBeforePromotion->isIntegralOrEnumerationType()) { + return TypeBeforePromotion; + } + } + return expr->getType(); +} + +StmtResult +Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, + Decl *CondVar) { + ExprResult CondResult; + + VarDecl *ConditionVar = 0; + if (CondVar) { + ConditionVar = cast<VarDecl>(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)); + 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<SwitchStmt>(Switch); + assert(SS == getCurFunction()->SwitchStack.back() && + "switch stack missing push/pop!"); + + SS->setBody(BodyStmt, SwitchLoc); + getCurFunction()->SwitchStack.pop_back(); + + if (SS->getCond() == 0) + return StmtError(); + + Expr *CondExpr = SS->getCond(); + Expr *CondExprBeforePromotion = CondExpr; + QualType CondTypeBeforePromotion = + GetTypeBeforeIntegralPromotion(CondExpr); + + // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. + UsualUnaryConversions(CondExpr); + QualType CondType = CondExpr->getType(); + SS->setCond(CondExpr); + + // 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 + : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion)); + bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); + + // 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 llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; + CaseValsTy CaseVals; + + // Keep track of any GNU case ranges we see. The APSInt is the low value. + typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; + CaseRangesTy CaseRanges; + + DefaultStmt *TheDefaultStmt = 0; + + bool CaseListIsErroneous = false; + + for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; + SC = SC->getNextSwitchCase()) { + + if (DefaultStmt *DS = dyn_cast<DefaultStmt>(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<CaseStmt>(SC); + + // We already verified that the expression has a i-c-e value (C99 + // 6.8.4.2p3) - get that value now. + Expr *Lo = CS->getLHS(); + + if (Lo->isTypeDependent() || Lo->isValueDependent()) { + HasDependentValue = true; + break; + } + + llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); + + // Convert the value to the same width/sign as the condition. + ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, + Lo->getLocStart(), + diag::warn_case_value_overflow); + + // If the LHS is not the same type as the condition, insert an implicit + // cast. + ImpCastExprToType(Lo, CondType, CK_IntegralCast); + 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; + bool ShouldCheckConstantCond = false; + if (!HasDependentValue && !TheDefaultStmt) { + Expr::EvalResult Result; + HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context); + if (HasConstantCond) { + assert(Result.Val.isInt() && "switch condition evaluated to non-int"); + ConstantCondValue = Result.Val.getInt(); + ShouldCheckConstantCond = true; + + assert(ConstantCondValue.getBitWidth() == CondWidth && + ConstantCondValue.isSigned() == CondIsSigned); + } + } + + // 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<llvm::APSInt> 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 = Hi->EvaluateAsInt(Context); + + // Convert the value to the same width/sign as the condition. + ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, + Hi->getLocStart(), + diag::warn_case_value_overflow); + + // If the LHS is not the same type as the condition, insert an implicit + // cast. + ImpCastExprToType(Hi, CondType, CK_IntegralCast); + 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<EnumType>(); + + // If switch has default case, then ignore it. + if (!CaseListIsErroneous && !HasConstantCond && ET) { + const EnumDecl *ED = ET->getDecl(); + typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 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. + // TODO: we might want to check whether case values are out of the + // enum even if we don't want to check whether all cases are handled. + if (!TheDefaultStmt) { + 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) + << ED->getDeclName(); + } + // 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) + << ED->getDeclName(); + } + + llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(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) + << ED->getDeclName(); + } + } + + // Check which enum vals aren't in switch + CaseValsTy::const_iterator CI = CaseVals.begin(); + CaseRangesTy::const_iterator RI = CaseRanges.begin(); + bool hasCasesNotInSwitch = false; + + llvm::SmallVector<DeclarationName,8> UnhandledNames; + + for (EnumValsTy::const_iterator 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()->EvaluateAsInt(Context); + AdjustAPSInt(Hi, CondWidth, CondIsSigned); + if (EI->first <= Hi) + break; + } + + if (RI == CaseRanges.end() || EI->first < RI->first) { + hasCasesNotInSwitch = true; + if (!TheDefaultStmt) + UnhandledNames.push_back(EI->second->getDeclName()); + } + } + + // Produce a nice diagnostic if multiple values aren't handled. + switch (UnhandledNames.size()) { + case 0: break; + case 1: + Diag(CondExpr->getExprLoc(), diag::warn_missing_case1) + << UnhandledNames[0]; + break; + case 2: + Diag(CondExpr->getExprLoc(), diag::warn_missing_case2) + << UnhandledNames[0] << UnhandledNames[1]; + break; + case 3: + Diag(CondExpr->getExprLoc(), diag::warn_missing_case3) + << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; + break; + default: + Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) + << (unsigned)UnhandledNames.size() + << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; + break; + } + + if (!hasCasesNotInSwitch) + SS->setAllEnumCasesCovered(); + } + } + + // 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<VarDecl>(CondVar); + CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); + if (CondResult.isInvalid()) + return StmtError(); + } + Expr *ConditionExpr = CondResult.take(); + if (!ConditionExpr) + return StmtError(); + + DiagnoseUnusedExprResult(Body); + + 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"); + + if (CheckBooleanCondition(Cond, DoLoc)) + return StmtError(); + + CheckImplicitConversions(Cond, DoLoc); + ExprResult 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 (!getLangOptions().CPlusPlus) { + if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(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<VarDecl>(*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<VarDecl>(secondVar); + SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); + if (SecondResult.isInvalid()) + return StmtError(); + } + + Expr *Third = third.release().takeAs<Expr>(); + + DiagnoseUnusedExprResult(First); + DiagnoseUnusedExprResult(Third); + DiagnoseUnusedExprResult(Body); + + 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) { + CheckImplicitConversions(E); + ExprResult Result = MaybeCreateExprWithCleanups(E); + if (Result.isInvalid()) return StmtError(); + return Owned(static_cast<Stmt*>(Result.get())); +} + +StmtResult +Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, + SourceLocation LParenLoc, + Stmt *First, Expr *Second, + SourceLocation RParenLoc, Stmt *Body) { + if (First) { + QualType FirstType; + if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { + if (!DS->isSingleDecl()) + return StmtError(Diag((*DS->decl_begin())->getLocation(), + diag::err_toomany_element_decls)); + + Decl *D = DS->getSingleDecl(); + FirstType = cast<ValueDecl>(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'. + VarDecl *VD = cast<VarDecl>(D); + if (VD->isLocalVarDecl() && !VD->hasLocalStorage()) + return StmtError(Diag(VD->getLocation(), + diag::err_non_variable_decl_in_for)); + } else { + Expr *FirstE = cast<Expr>(First); + if (!FirstE->isTypeDependent() && !FirstE->isLValue()) + return StmtError(Diag(First->getLocStart(), + diag::err_selector_element_not_lvalue) + << First->getSourceRange()); + + FirstType = static_cast<Expr*>(First)->getType(); + } + if (!FirstType->isDependentType() && + !FirstType->isObjCObjectPointerType() && + !FirstType->isBlockPointerType()) + Diag(ForLoc, diag::err_selector_element_type) + << FirstType << First->getSourceRange(); + } + if (Second && !Second->isTypeDependent()) { + DefaultFunctionArrayLvalueConversion(Second); + QualType SecondType = Second->getType(); + if (!SecondType->isObjCObjectPointerType()) + Diag(ForLoc, diag::err_collection_expr_type) + << SecondType << Second->getSourceRange(); + else if (const ObjCObjectPointerType *OPT = + SecondType->getAsObjCInterfacePointerType()) { + llvm::SmallVector<IdentifierInfo *, 4> KeyIdents; + IdentifierInfo* selIdent = + &Context.Idents.get("countByEnumeratingWithState"); + KeyIdents.push_back(selIdent); + selIdent = &Context.Idents.get("objects"); + KeyIdents.push_back(selIdent); + selIdent = &Context.Idents.get("count"); + KeyIdents.push_back(selIdent); + Selector CSelector = Context.Selectors.getSelector(3, &KeyIdents[0]); + if (ObjCInterfaceDecl *IDecl = OPT->getInterfaceDecl()) { + if (!IDecl->isForwardDecl() && + !IDecl->lookupInstanceMethod(CSelector)) { + // Must further look into private implementation methods. + if (!LookupPrivateInstanceMethod(CSelector, IDecl)) + Diag(ForLoc, diag::warn_collection_expr_type) + << SecondType << CSelector << Second->getSourceRange(); + } + } + } + } + return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, + ForLoc, RParenLoc)); +} + +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()); + AssignConvertType ConvTy = + CheckSingleAssignmentConstraints(DestTy, E); + if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) + return StmtError(); + } + + 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 +/// +/// \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<DeclRefExpr>(E->IgnoreParens()); + if (!DR) + return 0; + const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); + if (!VD) + return 0; + + if (VD->hasLocalStorage() && !VD->isExceptionVariable() && + !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() && + !VD->getType().isVolatileQualified() && + ((VD->getKind() == Decl::Var) || + (AllowFunctionParameter && VD->getKind() == Decl::ParmVar))) + return VD; + + return 0; +} + +/// \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) { + // 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 (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.getKind() != InitializationSequence::FailedSequence) { + 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<CXXConstructorDecl>(Step->Function.Function); + + const RValueReferenceType *RRefType + = Constructor->getParamDecl(0)->getType() + ->getAs<RValueReferenceType>(); + + // 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; +} + +/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. +/// +StmtResult +Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { + // If this is the first return we've seen in the block, infer the type of + // the block from it. + BlockScopeInfo *CurBlock = getCurBlock(); + if (CurBlock->ReturnType.isNull()) { + if (RetValExp) { + // Don't call UsualUnaryConversions(), since we don't want to do + // integer promotions here. + DefaultFunctionArrayLvalueConversion(RetValExp); + CurBlock->ReturnType = RetValExp->getType(); + if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { + // We have to remove a 'const' added to copied-in variable which was + // part of the implementation spec. and not the actual qualifier for + // the variable. + if (CDRE->isConstQualAdded()) + CurBlock->ReturnType.removeLocalConst(); // FIXME: local??? + } + } else + CurBlock->ReturnType = Context.VoidTy; + } + QualType FnRetType = CurBlock->ReturnType; + + if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { + Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) + << getCurFunctionOrMethodDecl()->getDeclName(); + 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. + ReturnStmt *Result = 0; + if (CurBlock->ReturnType->isVoidType()) { + if (RetValExp) { + Diag(ReturnLoc, diag::err_return_block_has_expr); + RetValExp = 0; + } + Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); + } else if (!RetValExp) { + return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); + } else { + const VarDecl *NRVOCandidate = 0; + + if (!FnRetType->isDependentType() && !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(); + } + + if (RetValExp) { + CheckImplicitConversions(RetValExp, ReturnLoc); + RetValExp = MaybeCreateExprWithCleanups(RetValExp); + } + + RetValExp = Res.takeAs<Expr>(); + if (RetValExp) + CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); + } + + 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 (getLangOptions().CPlusPlus && FnRetType->isRecordType() && + !CurContext->isDependentContext()) + FunctionScopes.back()->Returns.push_back(Result); + + return Owned(Result); +} + +StmtResult +Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { + if (getCurBlock()) + return ActOnBlockReturnStmt(ReturnLoc, RetValExp); + + QualType FnRetType; + if (const FunctionDecl *FD = getCurFunctionDecl()) { + FnRetType = FD->getResultType(); + if (FD->hasAttr<NoReturnAttr>() || + FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) + Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) + << getCurFunctionOrMethodDecl()->getDeclName(); + } else if (ObjCMethodDecl *MD = getCurMethodDecl()) + FnRetType = MD->getResultType(); + else // If we don't have a function/method context, bail. + return StmtError(); + + ReturnStmt *Result = 0; + if (FnRetType->isVoidType()) { + if (RetValExp && !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 { + IgnoredValueConversions(RetValExp); + ImpCastExprToType(RetValExp, Context.VoidTy, CK_ToVoid); + } + + // return (some void expression); is legal in C++. + if (D != diag::ext_return_has_void_expr || + !getLangOptions().CPlusPlus) { + NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); + Diag(ReturnLoc, D) + << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) + << RetValExp->getSourceRange(); + } + + 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 (getLangOptions().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 + + // 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<Expr>(); + 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 (getLangOptions().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.getLangOptions().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; +} + + +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<StringLiteral**>(constraints.get()); + Expr **Exprs = exprs.get(); + StringLiteral *AsmString = cast<StringLiteral>(asmString); + StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); + + llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; + + // The parser verifies that there is a string literal here. + if (AsmString->isWide()) + 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->isWide()) + return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) + << Literal->getSourceRange()); + + llvm::StringRef OutputName; + if (Names[i]) + OutputName = Names[i]->getName(); + + TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); + if (!Context.Target.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); + } + + llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; + + for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { + StringLiteral *Literal = Constraints[i]; + if (Literal->isWide()) + return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) + << Literal->getSourceRange()); + + llvm::StringRef InputName; + if (Names[i]) + InputName = Names[i]->getName(); + + TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); + if (!Context.Target.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()); + } + } + + DefaultFunctionArrayLvalueConversion(Exprs[i]); + + InputConstraintInfos.push_back(Info); + } + + // Check that the clobbers are valid. + for (unsigned i = 0; i != NumClobbers; i++) { + StringLiteral *Literal = Clobbers[i]; + if (Literal->isWide()) + return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) + << Literal->getSourceRange()); + + llvm::StringRef Clobber = Literal->getString(); + + if (!Context.Target.isValidGCCRegisterName(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. + llvm::SmallVector<AsmStmt::AsmStringPiece, 8> 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(); + Expr *OutputExpr = Exprs[TiedTo]; + Expr *InputExpr = Exprs[i+NumOutputs]; + 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 it and the asm string won't notice. Check this + // case now. + bool SmallerValueMentioned = false; + for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { + AsmStmt::AsmStringPiece &Piece = Pieces[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() == i+NumOutputs) { + if (InSize < OutSize) { + SmallerValueMentioned = true; + break; + } + } + + // 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() == TiedTo) { + if (InSize > OutSize) { + SmallerValueMentioned = true; + break; + } + } + } + + // 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; + + 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<VarDecl>(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 (!getLangOptions().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) { + DefaultLvalueConversion(Throw); + + 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<PointerType>(); + 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 (!getLangOptions().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); +} + +StmtResult +Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, + Stmt *SyncBody) { + getCurFunction()->setHasBranchProtectedScope(); + + DefaultLvalueConversion(SyncExpr); + + // Make sure the expression type is an ObjC pointer or "void *". + if (!SyncExpr->getType()->isDependentType() && + !SyncExpr->getType()->isObjCObjectPointerType()) { + const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); + if (!PT || !PT->getPointeeType()->isVoidType()) + return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) + << SyncExpr->getType() << SyncExpr->getSourceRange()); + } + + 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<VarDecl>(ExDecl), + HandlerBlock)); +} + +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) { + if (!getLangOptions().Exceptions) + 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(); + + llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; + + for (unsigned i = 0; i < NumHandlers; ++i) { + CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(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)); +} |
