SemaStmt.cpp revision b88ea9f1d1a402b0c9479c1c71a10cf65a5d4157 
1//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file implements semantic analysis for statements.
11//
12//===----------------------------------------------------------------------===//
13
14#include "Sema.h"
15#include "SemaInit.h"
16#include "clang/AST/APValue.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclObjC.h"
19#include "clang/AST/ExprCXX.h"
20#include "clang/AST/ExprObjC.h"
21#include "clang/AST/StmtObjC.h"
22#include "clang/AST/StmtCXX.h"
23#include "clang/Lex/Preprocessor.h"
24#include "clang/Basic/TargetInfo.h"
25#include "llvm/ADT/STLExtras.h"
26#include "llvm/ADT/SmallVector.h"
27using namespace clang;
28
29Sema::OwningStmtResult Sema::ActOnExprStmt(FullExprArg expr) {
30  Expr *E = expr->takeAs<Expr>();
31  assert(E && "ActOnExprStmt(): missing expression");
32  if (E->getType()->isObjCInterfaceType()) {
33    if (LangOpts.ObjCNonFragileABI)
34      Diag(E->getLocEnd(), diag::err_indirection_requires_nonfragile_object)
35             << E->getType();
36    else
37      Diag(E->getLocEnd(), diag::err_direct_interface_unsupported)
38             << E->getType();
39    return StmtError();
40  }
41  // C99 6.8.3p2: The expression in an expression statement is evaluated as a
42  // void expression for its side effects.  Conversion to void allows any
43  // operand, even incomplete types.
44
45  // Same thing in for stmt first clause (when expr) and third clause.
46  return Owned(static_cast<Stmt*>(E));
47}
48
49
50Sema::OwningStmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc) {
51  return Owned(new (Context) NullStmt(SemiLoc));
52}
53
54Sema::OwningStmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg,
55                                           SourceLocation StartLoc,
56                                           SourceLocation EndLoc) {
57  DeclGroupRef DG = dg.getAsVal<DeclGroupRef>();
58
59  // If we have an invalid decl, just return an error.
60  if (DG.isNull()) return StmtError();
61
62  return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc));
63}
64
65void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
66  DeclGroupRef DG = dg.getAsVal<DeclGroupRef>();
67
68  // If we have an invalid decl, just return.
69  if (DG.isNull() || !DG.isSingleDecl()) return;
70  // suppress any potential 'unused variable' warning.
71  DG.getSingleDecl()->setUsed();
72}
73
74void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
75  const Expr *E = dyn_cast_or_null<Expr>(S);
76  if (!E)
77    return;
78
79  SourceLocation Loc;
80  SourceRange R1, R2;
81  if (!E->isUnusedResultAWarning(Loc, R1, R2, Context))
82    return;
83
84  // Okay, we have an unused result.  Depending on what the base expression is,
85  // we might want to make a more specific diagnostic.  Check for one of these
86  // cases now.
87  unsigned DiagID = diag::warn_unused_expr;
88  E = E->IgnoreParens();
89  if (isa<ObjCImplicitSetterGetterRefExpr>(E))
90    DiagID = diag::warn_unused_property_expr;
91
92  if (const CXXExprWithTemporaries *Temps = dyn_cast<CXXExprWithTemporaries>(E))
93    E = Temps->getSubExpr();
94  if (const CXXZeroInitValueExpr *Zero = dyn_cast<CXXZeroInitValueExpr>(E)) {
95    if (const RecordType *RecordT = Zero->getType()->getAs<RecordType>())
96      if (CXXRecordDecl *RecordD = dyn_cast<CXXRecordDecl>(RecordT->getDecl()))
97        if (!RecordD->hasTrivialDestructor())
98          return;
99  }
100
101  if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
102    if (E->getType()->isVoidType())
103      return;
104
105    // If the callee has attribute pure, const, or warn_unused_result, warn with
106    // a more specific message to make it clear what is happening.
107    if (const Decl *FD = CE->getCalleeDecl()) {
108      if (FD->getAttr<WarnUnusedResultAttr>()) {
109        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result";
110        return;
111      }
112      if (FD->getAttr<PureAttr>()) {
113        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure";
114        return;
115      }
116      if (FD->getAttr<ConstAttr>()) {
117        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const";
118        return;
119      }
120    }
121  }
122  else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) {
123    const ObjCMethodDecl *MD = ME->getMethodDecl();
124    if (MD && MD->getAttr<WarnUnusedResultAttr>()) {
125      Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result";
126      return;
127    }
128  }
129  Diag(Loc, DiagID) << R1 << R2;
130}
131
132Action::OwningStmtResult
133Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
134                        MultiStmtArg elts, bool isStmtExpr) {
135  unsigned NumElts = elts.size();
136  Stmt **Elts = reinterpret_cast<Stmt**>(elts.release());
137  // If we're in C89 mode, check that we don't have any decls after stmts.  If
138  // so, emit an extension diagnostic.
139  if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) {
140    // Note that __extension__ can be around a decl.
141    unsigned i = 0;
142    // Skip over all declarations.
143    for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i)
144      /*empty*/;
145
146    // We found the end of the list or a statement.  Scan for another declstmt.
147    for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i)
148      /*empty*/;
149
150    if (i != NumElts) {
151      Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin();
152      Diag(D->getLocation(), diag::ext_mixed_decls_code);
153    }
154  }
155  // Warn about unused expressions in statements.
156  for (unsigned i = 0; i != NumElts; ++i) {
157    // Ignore statements that are last in a statement expression.
158    if (isStmtExpr && i == NumElts - 1)
159      continue;
160
161    DiagnoseUnusedExprResult(Elts[i]);
162  }
163
164  return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R));
165}
166
167Action::OwningStmtResult
168Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprArg lhsval,
169                    SourceLocation DotDotDotLoc, ExprArg rhsval,
170                    SourceLocation ColonLoc) {
171  assert((lhsval.get() != 0) && "missing expression in case statement");
172
173  // C99 6.8.4.2p3: The expression shall be an integer constant.
174  // However, GCC allows any evaluatable integer expression.
175  Expr *LHSVal = static_cast<Expr*>(lhsval.get());
176  if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() &&
177      VerifyIntegerConstantExpression(LHSVal))
178    return StmtError();
179
180  // GCC extension: The expression shall be an integer constant.
181
182  Expr *RHSVal = static_cast<Expr*>(rhsval.get());
183  if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() &&
184      VerifyIntegerConstantExpression(RHSVal)) {
185    RHSVal = 0;  // Recover by just forgetting about it.
186    rhsval = 0;
187  }
188
189  if (getSwitchStack().empty()) {
190    Diag(CaseLoc, diag::err_case_not_in_switch);
191    return StmtError();
192  }
193
194  // Only now release the smart pointers.
195  lhsval.release();
196  rhsval.release();
197  CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc,
198                                        ColonLoc);
199  getSwitchStack().back()->addSwitchCase(CS);
200  return Owned(CS);
201}
202
203/// ActOnCaseStmtBody - This installs a statement as the body of a case.
204void Sema::ActOnCaseStmtBody(StmtTy *caseStmt, StmtArg subStmt) {
205  CaseStmt *CS = static_cast<CaseStmt*>(caseStmt);
206  Stmt *SubStmt = subStmt.takeAs<Stmt>();
207  CS->setSubStmt(SubStmt);
208}
209
210Action::OwningStmtResult
211Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
212                       StmtArg subStmt, Scope *CurScope) {
213  Stmt *SubStmt = subStmt.takeAs<Stmt>();
214
215  if (getSwitchStack().empty()) {
216    Diag(DefaultLoc, diag::err_default_not_in_switch);
217    return Owned(SubStmt);
218  }
219
220  DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
221  getSwitchStack().back()->addSwitchCase(DS);
222  return Owned(DS);
223}
224
225Action::OwningStmtResult
226Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II,
227                     SourceLocation ColonLoc, StmtArg subStmt) {
228  Stmt *SubStmt = subStmt.takeAs<Stmt>();
229  // Look up the record for this label identifier.
230  LabelStmt *&LabelDecl = getLabelMap()[II];
231
232  // If not forward referenced or defined already, just create a new LabelStmt.
233  if (LabelDecl == 0)
234    return Owned(LabelDecl = new (Context) LabelStmt(IdentLoc, II, SubStmt));
235
236  assert(LabelDecl->getID() == II && "Label mismatch!");
237
238  // Otherwise, this label was either forward reference or multiply defined.  If
239  // multiply defined, reject it now.
240  if (LabelDecl->getSubStmt()) {
241    Diag(IdentLoc, diag::err_redefinition_of_label) << LabelDecl->getID();
242    Diag(LabelDecl->getIdentLoc(), diag::note_previous_definition);
243    return Owned(SubStmt);
244  }
245
246  // Otherwise, this label was forward declared, and we just found its real
247  // definition.  Fill in the forward definition and return it.
248  LabelDecl->setIdentLoc(IdentLoc);
249  LabelDecl->setSubStmt(SubStmt);
250  return Owned(LabelDecl);
251}
252
253Action::OwningStmtResult
254Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, DeclPtrTy CondVar,
255                  StmtArg ThenVal, SourceLocation ElseLoc,
256                  StmtArg ElseVal) {
257  OwningExprResult CondResult(CondVal.release());
258
259  VarDecl *ConditionVar = 0;
260  if (CondVar.get()) {
261    ConditionVar = CondVar.getAs<VarDecl>();
262    CondResult = CheckConditionVariable(ConditionVar);
263    if (CondResult.isInvalid())
264      return StmtError();
265  }
266  Expr *ConditionExpr = CondResult.takeAs<Expr>();
267  if (!ConditionExpr)
268    return StmtError();
269
270  if (CheckBooleanCondition(ConditionExpr, IfLoc)) {
271    CondResult = ConditionExpr;
272    return StmtError();
273  }
274
275  Stmt *thenStmt = ThenVal.takeAs<Stmt>();
276  DiagnoseUnusedExprResult(thenStmt);
277
278  // Warn if the if block has a null body without an else value.
279  // this helps prevent bugs due to typos, such as
280  // if (condition);
281  //   do_stuff();
282  if (!ElseVal.get()) {
283    if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt))
284      Diag(stmt->getSemiLoc(), diag::warn_empty_if_body);
285  }
286
287  Stmt *elseStmt = ElseVal.takeAs<Stmt>();
288  DiagnoseUnusedExprResult(elseStmt);
289
290  CondResult.release();
291  return Owned(new (Context) IfStmt(IfLoc, ConditionVar, ConditionExpr,
292                                    thenStmt, ElseLoc, elseStmt));
293}
294
295Action::OwningStmtResult
296Sema::ActOnStartOfSwitchStmt(FullExprArg cond, DeclPtrTy CondVar) {
297  OwningExprResult CondResult(cond.release());
298
299  VarDecl *ConditionVar = 0;
300  if (CondVar.get()) {
301    ConditionVar = CondVar.getAs<VarDecl>();
302    CondResult = CheckConditionVariable(ConditionVar);
303    if (CondResult.isInvalid())
304      return StmtError();
305  }
306  SwitchStmt *SS = new (Context) SwitchStmt(ConditionVar,
307                                            CondResult.takeAs<Expr>());
308  getSwitchStack().push_back(SS);
309  return Owned(SS);
310}
311
312/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have
313/// the specified width and sign.  If an overflow occurs, detect it and emit
314/// the specified diagnostic.
315void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val,
316                                              unsigned NewWidth, bool NewSign,
317                                              SourceLocation Loc,
318                                              unsigned DiagID) {
319  // Perform a conversion to the promoted condition type if needed.
320  if (NewWidth > Val.getBitWidth()) {
321    // If this is an extension, just do it.
322    Val.extend(NewWidth);
323    Val.setIsSigned(NewSign);
324
325    // If the input was signed and negative and the output is
326    // unsigned, don't bother to warn: this is implementation-defined
327    // behavior.
328    // FIXME: Introduce a second, default-ignored warning for this case?
329  } else if (NewWidth < Val.getBitWidth()) {
330    // If this is a truncation, check for overflow.
331    llvm::APSInt ConvVal(Val);
332    ConvVal.trunc(NewWidth);
333    ConvVal.setIsSigned(NewSign);
334    ConvVal.extend(Val.getBitWidth());
335    ConvVal.setIsSigned(Val.isSigned());
336    if (ConvVal != Val)
337      Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10);
338
339    // Regardless of whether a diagnostic was emitted, really do the
340    // truncation.
341    Val.trunc(NewWidth);
342    Val.setIsSigned(NewSign);
343  } else if (NewSign != Val.isSigned()) {
344    // Convert the sign to match the sign of the condition.  This can cause
345    // overflow as well: unsigned(INTMIN)
346    // We don't diagnose this overflow, because it is implementation-defined
347    // behavior.
348    // FIXME: Introduce a second, default-ignored warning for this case?
349    llvm::APSInt OldVal(Val);
350    Val.setIsSigned(NewSign);
351  }
352}
353
354namespace {
355  struct CaseCompareFunctor {
356    bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
357                    const llvm::APSInt &RHS) {
358      return LHS.first < RHS;
359    }
360    bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
361                    const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
362      return LHS.first < RHS.first;
363    }
364    bool operator()(const llvm::APSInt &LHS,
365                    const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
366      return LHS < RHS.first;
367    }
368  };
369}
370
371/// CmpCaseVals - Comparison predicate for sorting case values.
372///
373static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
374                        const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
375  if (lhs.first < rhs.first)
376    return true;
377
378  if (lhs.first == rhs.first &&
379      lhs.second->getCaseLoc().getRawEncoding()
380       < rhs.second->getCaseLoc().getRawEncoding())
381    return true;
382  return false;
383}
384
385/// CmpEnumVals - Comparison predicate for sorting enumeration values.
386///
387static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
388                        const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
389{
390  return lhs.first < rhs.first;
391}
392
393/// EqEnumVals - Comparison preficate for uniqing enumeration values.
394///
395static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
396                       const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
397{
398  return lhs.first == rhs.first;
399}
400
401/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
402/// potentially integral-promoted expression @p expr.
403static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) {
404  const ImplicitCastExpr *ImplicitCast =
405      dyn_cast_or_null<ImplicitCastExpr>(expr);
406  if (ImplicitCast != NULL) {
407    const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr();
408    QualType TypeBeforePromotion = ExprBeforePromotion->getType();
409    if (TypeBeforePromotion->isIntegralType()) {
410      return TypeBeforePromotion;
411    }
412  }
413  return expr->getType();
414}
415
416/// \brief Check (and possibly convert) the condition in a switch
417/// statement in C++.
418static bool CheckCXXSwitchCondition(Sema &S, SourceLocation SwitchLoc,
419                                    Expr *&CondExpr) {
420  if (CondExpr->isTypeDependent())
421    return false;
422
423  QualType CondType = CondExpr->getType();
424
425  // C++ 6.4.2.p2:
426  // The condition shall be of integral type, enumeration type, or of a class
427  // type for which a single conversion function to integral or enumeration
428  // type exists (12.3). If the condition is of class type, the condition is
429  // converted by calling that conversion function, and the result of the
430  // conversion is used in place of the original condition for the remainder
431  // of this section. Integral promotions are performed.
432
433  // Make sure that the condition expression has a complete type,
434  // otherwise we'll never find any conversions.
435  if (S.RequireCompleteType(SwitchLoc, CondType,
436                            S.PDiag(diag::err_switch_incomplete_class_type)
437                              << CondExpr->getSourceRange()))
438    return true;
439
440  UnresolvedSet<4> ViableConversions;
441  UnresolvedSet<4> ExplicitConversions;
442  if (const RecordType *RecordTy = CondType->getAs<RecordType>()) {
443    const UnresolvedSetImpl *Conversions
444      = cast<CXXRecordDecl>(RecordTy->getDecl())
445                                             ->getVisibleConversionFunctions();
446    for (UnresolvedSetImpl::iterator I = Conversions->begin(),
447           E = Conversions->end(); I != E; ++I) {
448      if (CXXConversionDecl *Conversion
449            = dyn_cast<CXXConversionDecl>((*I)->getUnderlyingDecl()))
450        if (Conversion->getConversionType().getNonReferenceType()
451              ->isIntegralType()) {
452          if (Conversion->isExplicit())
453            ExplicitConversions.addDecl(I.getDecl(), I.getAccess());
454          else
455            ViableConversions.addDecl(I.getDecl(), I.getAccess());
456        }
457    }
458
459    switch (ViableConversions.size()) {
460    case 0:
461      if (ExplicitConversions.size() == 1) {
462        DeclAccessPair Found = ExplicitConversions[0];
463        CXXConversionDecl *Conversion =
464          cast<CXXConversionDecl>(Found->getUnderlyingDecl());
465        // The user probably meant to invoke the given explicit
466        // conversion; use it.
467        QualType ConvTy
468          = Conversion->getConversionType().getNonReferenceType();
469        std::string TypeStr;
470        ConvTy.getAsStringInternal(TypeStr, S.Context.PrintingPolicy);
471
472        S.Diag(SwitchLoc, diag::err_switch_explicit_conversion)
473          << CondType << ConvTy << CondExpr->getSourceRange()
474          << FixItHint::CreateInsertion(CondExpr->getLocStart(),
475                                        "static_cast<" + TypeStr + ">(")
476          << FixItHint::CreateInsertion(
477                            S.PP.getLocForEndOfToken(CondExpr->getLocEnd()),
478                               ")");
479        S.Diag(Conversion->getLocation(), diag::note_switch_conversion)
480          << ConvTy->isEnumeralType() << ConvTy;
481
482        // If we aren't in a SFINAE context, build a call to the
483        // explicit conversion function.
484        if (S.isSFINAEContext())
485          return true;
486
487        S.CheckMemberOperatorAccess(CondExpr->getExprLoc(),
488                                    CondExpr, 0, Found);
489        CondExpr = S.BuildCXXMemberCallExpr(CondExpr, Found, Conversion);
490      }
491
492      // We'll complain below about a non-integral condition type.
493      break;
494
495    case 1: {
496      // Apply this conversion.
497      DeclAccessPair Found = ViableConversions[0];
498      S.CheckMemberOperatorAccess(CondExpr->getExprLoc(),
499                                  CondExpr, 0, Found);
500      CondExpr = S.BuildCXXMemberCallExpr(CondExpr, Found,
501                        cast<CXXConversionDecl>(Found->getUnderlyingDecl()));
502      break;
503    }
504
505    default:
506      S.Diag(SwitchLoc, diag::err_switch_multiple_conversions)
507        << CondType << CondExpr->getSourceRange();
508      for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
509        CXXConversionDecl *Conv
510          = cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl());
511        QualType ConvTy = Conv->getConversionType().getNonReferenceType();
512        S.Diag(Conv->getLocation(), diag::note_switch_conversion)
513          << ConvTy->isEnumeralType() << ConvTy;
514      }
515      return true;
516    }
517  }
518
519  return false;
520}
521
522/// ActOnSwitchBodyError - This is called if there is an error parsing the
523/// body of the switch stmt instead of ActOnFinishSwitchStmt.
524void Sema::ActOnSwitchBodyError(SourceLocation SwitchLoc, StmtArg Switch,
525                                StmtArg Body) {
526  // Keep the switch stack balanced.
527  assert(getSwitchStack().back() == (SwitchStmt*)Switch.get() &&
528         "switch stack missing push/pop!");
529  getSwitchStack().pop_back();
530}
531
532Action::OwningStmtResult
533Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, StmtArg Switch,
534                            StmtArg Body) {
535  Stmt *BodyStmt = Body.takeAs<Stmt>();
536
537  SwitchStmt *SS = getSwitchStack().back();
538  assert(SS == (SwitchStmt*)Switch.get() && "switch stack missing push/pop!");
539
540  SS->setBody(BodyStmt, SwitchLoc);
541  getSwitchStack().pop_back();
542
543  if (SS->getCond() == 0) {
544    SS->Destroy(Context);
545    return StmtError();
546  }
547
548  Expr *CondExpr = SS->getCond();
549  QualType CondTypeBeforePromotion =
550      GetTypeBeforeIntegralPromotion(CondExpr);
551
552  if (getLangOptions().CPlusPlus &&
553      CheckCXXSwitchCondition(*this, SwitchLoc, CondExpr))
554    return StmtError();
555
556  // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
557  UsualUnaryConversions(CondExpr);
558  QualType CondType = CondExpr->getType();
559  SS->setCond(CondExpr);
560
561  // C++ 6.4.2.p2:
562  // Integral promotions are performed (on the switch condition).
563  //
564  // A case value unrepresentable by the original switch condition
565  // type (before the promotion) doesn't make sense, even when it can
566  // be represented by the promoted type.  Therefore we need to find
567  // the pre-promotion type of the switch condition.
568  if (!CondExpr->isTypeDependent()) {
569    if (!CondType->isIntegerType()) { // C99 6.8.4.2p1
570      Diag(SwitchLoc, diag::err_typecheck_statement_requires_integer)
571          << CondType << CondExpr->getSourceRange();
572      return StmtError();
573    }
574
575    if (CondTypeBeforePromotion->isBooleanType()) {
576      // switch(bool_expr) {...} is often a programmer error, e.g.
577      //   switch(n && mask) { ... }  // Doh - should be "n & mask".
578      // One can always use an if statement instead of switch(bool_expr).
579      Diag(SwitchLoc, diag::warn_bool_switch_condition)
580          << CondExpr->getSourceRange();
581    }
582  }
583
584  // Get the bitwidth of the switched-on value before promotions.  We must
585  // convert the integer case values to this width before comparison.
586  bool HasDependentValue
587    = CondExpr->isTypeDependent() || CondExpr->isValueDependent();
588  unsigned CondWidth
589    = HasDependentValue? 0
590      : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion));
591  bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType();
592
593  // Accumulate all of the case values in a vector so that we can sort them
594  // and detect duplicates.  This vector contains the APInt for the case after
595  // it has been converted to the condition type.
596  typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
597  CaseValsTy CaseVals;
598
599  // Keep track of any GNU case ranges we see.  The APSInt is the low value.
600  typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy;
601  CaseRangesTy CaseRanges;
602
603  DefaultStmt *TheDefaultStmt = 0;
604
605  bool CaseListIsErroneous = false;
606
607  for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
608       SC = SC->getNextSwitchCase()) {
609
610    if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) {
611      if (TheDefaultStmt) {
612        Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
613        Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev);
614
615        // FIXME: Remove the default statement from the switch block so that
616        // we'll return a valid AST.  This requires recursing down the AST and
617        // finding it, not something we are set up to do right now.  For now,
618        // just lop the entire switch stmt out of the AST.
619        CaseListIsErroneous = true;
620      }
621      TheDefaultStmt = DS;
622
623    } else {
624      CaseStmt *CS = cast<CaseStmt>(SC);
625
626      // We already verified that the expression has a i-c-e value (C99
627      // 6.8.4.2p3) - get that value now.
628      Expr *Lo = CS->getLHS();
629
630      if (Lo->isTypeDependent() || Lo->isValueDependent()) {
631        HasDependentValue = true;
632        break;
633      }
634
635      llvm::APSInt LoVal = Lo->EvaluateAsInt(Context);
636
637      // Convert the value to the same width/sign as the condition.
638      ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned,
639                                         CS->getLHS()->getLocStart(),
640                                         diag::warn_case_value_overflow);
641
642      // If the LHS is not the same type as the condition, insert an implicit
643      // cast.
644      ImpCastExprToType(Lo, CondType, CastExpr::CK_IntegralCast);
645      CS->setLHS(Lo);
646
647      // If this is a case range, remember it in CaseRanges, otherwise CaseVals.
648      if (CS->getRHS()) {
649        if (CS->getRHS()->isTypeDependent() ||
650            CS->getRHS()->isValueDependent()) {
651          HasDependentValue = true;
652          break;
653        }
654        CaseRanges.push_back(std::make_pair(LoVal, CS));
655      } else
656        CaseVals.push_back(std::make_pair(LoVal, CS));
657    }
658  }
659
660  if (!HasDependentValue) {
661    // Sort all the scalar case values so we can easily detect duplicates.
662    std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals);
663
664    if (!CaseVals.empty()) {
665      for (unsigned i = 0, e = CaseVals.size()-1; i != e; ++i) {
666        if (CaseVals[i].first == CaseVals[i+1].first) {
667          // If we have a duplicate, report it.
668          Diag(CaseVals[i+1].second->getLHS()->getLocStart(),
669               diag::err_duplicate_case) << CaseVals[i].first.toString(10);
670          Diag(CaseVals[i].second->getLHS()->getLocStart(),
671               diag::note_duplicate_case_prev);
672          // FIXME: We really want to remove the bogus case stmt from the
673          // substmt, but we have no way to do this right now.
674          CaseListIsErroneous = true;
675        }
676      }
677    }
678
679    // Detect duplicate case ranges, which usually don't exist at all in
680    // the first place.
681    if (!CaseRanges.empty()) {
682      // Sort all the case ranges by their low value so we can easily detect
683      // overlaps between ranges.
684      std::stable_sort(CaseRanges.begin(), CaseRanges.end());
685
686      // Scan the ranges, computing the high values and removing empty ranges.
687      std::vector<llvm::APSInt> HiVals;
688      for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
689        CaseStmt *CR = CaseRanges[i].second;
690        Expr *Hi = CR->getRHS();
691        llvm::APSInt HiVal = Hi->EvaluateAsInt(Context);
692
693        // Convert the value to the same width/sign as the condition.
694        ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned,
695                                           CR->getRHS()->getLocStart(),
696                                           diag::warn_case_value_overflow);
697
698        // If the LHS is not the same type as the condition, insert an implicit
699        // cast.
700        ImpCastExprToType(Hi, CondType, CastExpr::CK_IntegralCast);
701        CR->setRHS(Hi);
702
703        // If the low value is bigger than the high value, the case is empty.
704        if (CaseRanges[i].first > HiVal) {
705          Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range)
706            << SourceRange(CR->getLHS()->getLocStart(),
707                           CR->getRHS()->getLocEnd());
708          CaseRanges.erase(CaseRanges.begin()+i);
709          --i, --e;
710          continue;
711        }
712        HiVals.push_back(HiVal);
713      }
714
715      // Rescan the ranges, looking for overlap with singleton values and other
716      // ranges.  Since the range list is sorted, we only need to compare case
717      // ranges with their neighbors.
718      for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
719        llvm::APSInt &CRLo = CaseRanges[i].first;
720        llvm::APSInt &CRHi = HiVals[i];
721        CaseStmt *CR = CaseRanges[i].second;
722
723        // Check to see whether the case range overlaps with any
724        // singleton cases.
725        CaseStmt *OverlapStmt = 0;
726        llvm::APSInt OverlapVal(32);
727
728        // Find the smallest value >= the lower bound.  If I is in the
729        // case range, then we have overlap.
730        CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(),
731                                                  CaseVals.end(), CRLo,
732                                                  CaseCompareFunctor());
733        if (I != CaseVals.end() && I->first < CRHi) {
734          OverlapVal  = I->first;   // Found overlap with scalar.
735          OverlapStmt = I->second;
736        }
737
738        // Find the smallest value bigger than the upper bound.
739        I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor());
740        if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
741          OverlapVal  = (I-1)->first;      // Found overlap with scalar.
742          OverlapStmt = (I-1)->second;
743        }
744
745        // Check to see if this case stmt overlaps with the subsequent
746        // case range.
747        if (i && CRLo <= HiVals[i-1]) {
748          OverlapVal  = HiVals[i-1];       // Found overlap with range.
749          OverlapStmt = CaseRanges[i-1].second;
750        }
751
752        if (OverlapStmt) {
753          // If we have a duplicate, report it.
754          Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case)
755            << OverlapVal.toString(10);
756          Diag(OverlapStmt->getLHS()->getLocStart(),
757               diag::note_duplicate_case_prev);
758          // FIXME: We really want to remove the bogus case stmt from the
759          // substmt, but we have no way to do this right now.
760          CaseListIsErroneous = true;
761        }
762      }
763    }
764
765    // Check to see if switch is over an Enum and handles all of its
766    // values
767    const EnumType* ET = CondTypeBeforePromotion->getAs<EnumType>();
768    // If switch has default case, then ignore it.
769    if (!CaseListIsErroneous && !TheDefaultStmt && ET) {
770      const EnumDecl *ED = ET->getDecl();
771      typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy;
772      EnumValsTy EnumVals;
773
774      // Gather all enum values, set their type and sort them, allowing easier comparison
775      // with CaseVals.
776      for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); EDI != ED->enumerator_end(); EDI++) {
777        llvm::APSInt Val = (*EDI)->getInitVal();
778        if(Val.getBitWidth() < CondWidth)
779          Val.extend(CondWidth);
780        Val.setIsSigned(CondIsSigned);
781        EnumVals.push_back(std::make_pair(Val, (*EDI)));
782      }
783      std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals);
784      EnumValsTy::iterator EIend = std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
785      // See which case values aren't in enum
786      EnumValsTy::const_iterator EI = EnumVals.begin();
787      for (CaseValsTy::const_iterator CI = CaseVals.begin(); CI != CaseVals.end(); CI++) {
788        while (EI != EIend && EI->first < CI->first)
789          EI++;
790        if (EI == EIend || EI->first > CI->first)
791            Diag(CI->second->getLHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName();
792      }
793      // See which of case ranges aren't in enum
794      EI = EnumVals.begin();
795      for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); RI != CaseRanges.end() && EI != EIend; RI++) {
796        while (EI != EIend && EI->first < RI->first)
797          EI++;
798
799        if (EI == EIend || EI->first != RI->first) {
800          Diag(RI->second->getLHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName();
801        }
802
803        llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context);
804        while (EI != EIend && EI->first < Hi)
805          EI++;
806        if (EI == EIend || EI->first != Hi)
807          Diag(RI->second->getRHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName();
808      }
809      //Check which enum vals aren't in switch
810      CaseValsTy::const_iterator CI = CaseVals.begin();
811      CaseRangesTy::const_iterator RI = CaseRanges.begin();
812      EI = EnumVals.begin();
813      for (; EI != EIend; EI++) {
814        //Drop unneeded case values
815        llvm::APSInt CIVal;
816        while (CI != CaseVals.end() && CI->first < EI->first)
817          CI++;
818
819        if (CI != CaseVals.end() && CI->first == EI->first)
820          continue;
821
822        //Drop unneeded case ranges
823        for (; RI != CaseRanges.end(); RI++) {
824          llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context);
825          if (EI->first <= Hi)
826            break;
827        }
828
829        if (RI == CaseRanges.end() || EI->first < RI->first)
830          Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) << EI->second->getDeclName();
831      }
832    }
833  }
834
835  // FIXME: If the case list was broken is some way, we don't have a good system
836  // to patch it up.  Instead, just return the whole substmt as broken.
837  if (CaseListIsErroneous)
838    return StmtError();
839
840  Switch.release();
841  return Owned(SS);
842}
843
844Action::OwningStmtResult
845Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond,
846                     DeclPtrTy CondVar, StmtArg Body) {
847  OwningExprResult CondResult(Cond.release());
848
849  VarDecl *ConditionVar = 0;
850  if (CondVar.get()) {
851    ConditionVar = CondVar.getAs<VarDecl>();
852    CondResult = CheckConditionVariable(ConditionVar);
853    if (CondResult.isInvalid())
854      return StmtError();
855  }
856  Expr *ConditionExpr = CondResult.takeAs<Expr>();
857  if (!ConditionExpr)
858    return StmtError();
859
860  if (CheckBooleanCondition(ConditionExpr, WhileLoc)) {
861    CondResult = ConditionExpr;
862    return StmtError();
863  }
864
865  Stmt *bodyStmt = Body.takeAs<Stmt>();
866  DiagnoseUnusedExprResult(bodyStmt);
867
868  CondResult.release();
869  return Owned(new (Context) WhileStmt(ConditionVar, ConditionExpr, bodyStmt,
870                                       WhileLoc));
871}
872
873Action::OwningStmtResult
874Sema::ActOnDoStmt(SourceLocation DoLoc, StmtArg Body,
875                  SourceLocation WhileLoc, SourceLocation CondLParen,
876                  ExprArg Cond, SourceLocation CondRParen) {
877  Expr *condExpr = Cond.takeAs<Expr>();
878  assert(condExpr && "ActOnDoStmt(): missing expression");
879
880  if (CheckBooleanCondition(condExpr, DoLoc)) {
881    Cond = condExpr;
882    return StmtError();
883  }
884
885  Stmt *bodyStmt = Body.takeAs<Stmt>();
886  DiagnoseUnusedExprResult(bodyStmt);
887
888  Cond.release();
889  return Owned(new (Context) DoStmt(bodyStmt, condExpr, DoLoc,
890                                    WhileLoc, CondRParen));
891}
892
893Action::OwningStmtResult
894Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
895                   StmtArg first, FullExprArg second, DeclPtrTy secondVar,
896                   FullExprArg third,
897                   SourceLocation RParenLoc, StmtArg body) {
898  Stmt *First  = static_cast<Stmt*>(first.get());
899
900  if (!getLangOptions().CPlusPlus) {
901    if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) {
902      // C99 6.8.5p3: The declaration part of a 'for' statement shall only
903      // declare identifiers for objects having storage class 'auto' or
904      // 'register'.
905      for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end();
906           DI!=DE; ++DI) {
907        VarDecl *VD = dyn_cast<VarDecl>(*DI);
908        if (VD && VD->isBlockVarDecl() && !VD->hasLocalStorage())
909          VD = 0;
910        if (VD == 0)
911          Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for);
912        // FIXME: mark decl erroneous!
913      }
914    }
915  }
916
917  OwningExprResult SecondResult(second.release());
918  VarDecl *ConditionVar = 0;
919  if (secondVar.get()) {
920    ConditionVar = secondVar.getAs<VarDecl>();
921    SecondResult = CheckConditionVariable(ConditionVar);
922    if (SecondResult.isInvalid())
923      return StmtError();
924  }
925
926  Expr *Second = SecondResult.takeAs<Expr>();
927  if (Second && CheckBooleanCondition(Second, ForLoc)) {
928    SecondResult = Second;
929    return StmtError();
930  }
931
932  Expr *Third  = third.release().takeAs<Expr>();
933  Stmt *Body  = static_cast<Stmt*>(body.get());
934
935  DiagnoseUnusedExprResult(First);
936  DiagnoseUnusedExprResult(Third);
937  DiagnoseUnusedExprResult(Body);
938
939  first.release();
940  body.release();
941  return Owned(new (Context) ForStmt(First, Second, ConditionVar, Third, Body,
942                                     ForLoc, LParenLoc, RParenLoc));
943}
944
945Action::OwningStmtResult
946Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
947                                 SourceLocation LParenLoc,
948                                 StmtArg first, ExprArg second,
949                                 SourceLocation RParenLoc, StmtArg body) {
950  Stmt *First  = static_cast<Stmt*>(first.get());
951  Expr *Second = static_cast<Expr*>(second.get());
952  Stmt *Body  = static_cast<Stmt*>(body.get());
953  if (First) {
954    QualType FirstType;
955    if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) {
956      if (!DS->isSingleDecl())
957        return StmtError(Diag((*DS->decl_begin())->getLocation(),
958                         diag::err_toomany_element_decls));
959
960      Decl *D = DS->getSingleDecl();
961      FirstType = cast<ValueDecl>(D)->getType();
962      // C99 6.8.5p3: The declaration part of a 'for' statement shall only
963      // declare identifiers for objects having storage class 'auto' or
964      // 'register'.
965      VarDecl *VD = cast<VarDecl>(D);
966      if (VD->isBlockVarDecl() && !VD->hasLocalStorage())
967        return StmtError(Diag(VD->getLocation(),
968                              diag::err_non_variable_decl_in_for));
969    } else {
970      if (cast<Expr>(First)->isLvalue(Context) != Expr::LV_Valid)
971        return StmtError(Diag(First->getLocStart(),
972                   diag::err_selector_element_not_lvalue)
973          << First->getSourceRange());
974
975      FirstType = static_cast<Expr*>(First)->getType();
976    }
977    if (!FirstType->isObjCObjectPointerType() &&
978        !FirstType->isBlockPointerType())
979        Diag(ForLoc, diag::err_selector_element_type)
980          << FirstType << First->getSourceRange();
981  }
982  if (Second) {
983    DefaultFunctionArrayLvalueConversion(Second);
984    QualType SecondType = Second->getType();
985    if (!SecondType->isObjCObjectPointerType())
986      Diag(ForLoc, diag::err_collection_expr_type)
987        << SecondType << Second->getSourceRange();
988  }
989  first.release();
990  second.release();
991  body.release();
992  return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body,
993                                                   ForLoc, RParenLoc));
994}
995
996Action::OwningStmtResult
997Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc,
998                    IdentifierInfo *LabelII) {
999  // Look up the record for this label identifier.
1000  LabelStmt *&LabelDecl = getLabelMap()[LabelII];
1001
1002  // If we haven't seen this label yet, create a forward reference.
1003  if (LabelDecl == 0)
1004    LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0);
1005
1006  return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc));
1007}
1008
1009Action::OwningStmtResult
1010Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
1011                            ExprArg DestExp) {
1012  // Convert operand to void*
1013  Expr* E = DestExp.takeAs<Expr>();
1014  if (!E->isTypeDependent()) {
1015    QualType ETy = E->getType();
1016    QualType DestTy = Context.getPointerType(Context.VoidTy.withConst());
1017    AssignConvertType ConvTy =
1018      CheckSingleAssignmentConstraints(DestTy, E);
1019    if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing))
1020      return StmtError();
1021  }
1022  return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E));
1023}
1024
1025Action::OwningStmtResult
1026Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
1027  Scope *S = CurScope->getContinueParent();
1028  if (!S) {
1029    // C99 6.8.6.2p1: A break shall appear only in or as a loop body.
1030    return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop));
1031  }
1032
1033  return Owned(new (Context) ContinueStmt(ContinueLoc));
1034}
1035
1036Action::OwningStmtResult
1037Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
1038  Scope *S = CurScope->getBreakParent();
1039  if (!S) {
1040    // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
1041    return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch));
1042  }
1043
1044  return Owned(new (Context) BreakStmt(BreakLoc));
1045}
1046
1047/// ActOnBlockReturnStmt - Utility routine to figure out block's return type.
1048///
1049Action::OwningStmtResult
1050Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
1051  // If this is the first return we've seen in the block, infer the type of
1052  // the block from it.
1053  BlockScopeInfo *CurBlock = getCurBlock();
1054  if (CurBlock->ReturnType.isNull()) {
1055    if (RetValExp) {
1056      // Don't call UsualUnaryConversions(), since we don't want to do
1057      // integer promotions here.
1058      DefaultFunctionArrayLvalueConversion(RetValExp);
1059      CurBlock->ReturnType = RetValExp->getType();
1060      if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) {
1061        // We have to remove a 'const' added to copied-in variable which was
1062        // part of the implementation spec. and not the actual qualifier for
1063        // the variable.
1064        if (CDRE->isConstQualAdded())
1065           CurBlock->ReturnType.removeConst();
1066      }
1067    } else
1068      CurBlock->ReturnType = Context.VoidTy;
1069  }
1070  QualType FnRetType = CurBlock->ReturnType;
1071
1072  if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) {
1073    Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr)
1074      << getCurFunctionOrMethodDecl()->getDeclName();
1075    return StmtError();
1076  }
1077
1078  // Otherwise, verify that this result type matches the previous one.  We are
1079  // pickier with blocks than for normal functions because we don't have GCC
1080  // compatibility to worry about here.
1081  if (CurBlock->ReturnType->isVoidType()) {
1082    if (RetValExp) {
1083      Diag(ReturnLoc, diag::err_return_block_has_expr);
1084      RetValExp->Destroy(Context);
1085      RetValExp = 0;
1086    }
1087    return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp));
1088  }
1089
1090  if (!RetValExp)
1091    return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr));
1092
1093  if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) {
1094    // we have a non-void block with an expression, continue checking
1095
1096    // C99 6.8.6.4p3(136): The return statement is not an assignment. The
1097    // overlap restriction of subclause 6.5.16.1 does not apply to the case of
1098    // function return.
1099
1100    // In C++ the return statement is handled via a copy initialization.
1101    // the C version of which boils down to CheckSingleAssignmentConstraints.
1102    OwningExprResult Res = PerformCopyInitialization(
1103                             InitializedEntity::InitializeResult(ReturnLoc,
1104                                                                 FnRetType),
1105                             SourceLocation(),
1106                             Owned(RetValExp));
1107    if (Res.isInvalid()) {
1108      // FIXME: Cleanup temporaries here, anyway?
1109      return StmtError();
1110    }
1111
1112    RetValExp = Res.takeAs<Expr>();
1113    if (RetValExp)
1114      CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc);
1115  }
1116
1117  return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp));
1118}
1119
1120/// IsReturnCopyElidable - Whether returning @p RetExpr from a function that
1121/// returns a @p RetType fulfills the criteria for copy elision (C++0x 12.8p15).
1122static bool IsReturnCopyElidable(ASTContext &Ctx, QualType RetType,
1123                                 Expr *RetExpr) {
1124  QualType ExprType = RetExpr->getType();
1125  // - in a return statement in a function with ...
1126  // ... a class return type ...
1127  if (!RetType->isRecordType())
1128    return false;
1129  // ... the same cv-unqualified type as the function return type ...
1130  if (!Ctx.hasSameUnqualifiedType(RetType, ExprType))
1131    return false;
1132  // ... the expression is the name of a non-volatile automatic object ...
1133  // We ignore parentheses here.
1134  // FIXME: Is this compliant?
1135  const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens());
1136  if (!DR)
1137    return false;
1138  const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl());
1139  if (!VD)
1140    return false;
1141  return VD->hasLocalStorage() && !VD->getType()->isReferenceType()
1142    && !VD->getType().isVolatileQualified();
1143}
1144
1145Action::OwningStmtResult
1146Sema::ActOnReturnStmt(SourceLocation ReturnLoc, ExprArg rex) {
1147  Expr *RetValExp = rex.takeAs<Expr>();
1148  if (getCurBlock())
1149    return ActOnBlockReturnStmt(ReturnLoc, RetValExp);
1150
1151  QualType FnRetType;
1152  if (const FunctionDecl *FD = getCurFunctionDecl()) {
1153    FnRetType = FD->getResultType();
1154    if (FD->hasAttr<NoReturnAttr>() ||
1155        FD->getType()->getAs<FunctionType>()->getNoReturnAttr())
1156      Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr)
1157        << getCurFunctionOrMethodDecl()->getDeclName();
1158  } else if (ObjCMethodDecl *MD = getCurMethodDecl())
1159    FnRetType = MD->getResultType();
1160  else // If we don't have a function/method context, bail.
1161    return StmtError();
1162
1163  if (FnRetType->isVoidType()) {
1164    if (RetValExp && !RetValExp->isTypeDependent()) {
1165      // C99 6.8.6.4p1 (ext_ since GCC warns)
1166      unsigned D = diag::ext_return_has_expr;
1167      if (RetValExp->getType()->isVoidType())
1168        D = diag::ext_return_has_void_expr;
1169
1170      // return (some void expression); is legal in C++.
1171      if (D != diag::ext_return_has_void_expr ||
1172          !getLangOptions().CPlusPlus) {
1173        NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
1174        Diag(ReturnLoc, D)
1175          << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl)
1176          << RetValExp->getSourceRange();
1177      }
1178
1179      RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp);
1180    }
1181    return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp));
1182  }
1183
1184  if (!RetValExp && !FnRetType->isDependentType()) {
1185    unsigned DiagID = diag::warn_return_missing_expr;  // C90 6.6.6.4p4
1186    // C99 6.8.6.4p1 (ext_ since GCC warns)
1187    if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr;
1188
1189    if (FunctionDecl *FD = getCurFunctionDecl())
1190      Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/;
1191    else
1192      Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/;
1193    return Owned(new (Context) ReturnStmt(ReturnLoc, (Expr*)0));
1194  }
1195
1196  if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) {
1197    // we have a non-void function with an expression, continue checking
1198
1199    // C99 6.8.6.4p3(136): The return statement is not an assignment. The
1200    // overlap restriction of subclause 6.5.16.1 does not apply to the case of
1201    // function return.
1202
1203    // C++0x 12.8p15: When certain criteria are met, an implementation is
1204    //   allowed to omit the copy construction of a class object, [...]
1205    //   - in a return statement in a function with a class return type, when
1206    //     the expression is the name of a non-volatile automatic object with
1207    //     the same cv-unqualified type as the function return type, the copy
1208    //     operation can be omitted [...]
1209    // C++0x 12.8p16: When the criteria for elision of a copy operation are met
1210    //   and the object to be copied is designated by an lvalue, overload
1211    //   resolution to select the constructor for the copy is first performed
1212    //   as if the object were designated by an rvalue.
1213    // Note that we only compute Elidable if we're in C++0x, since we don't
1214    // care otherwise.
1215    bool Elidable = getLangOptions().CPlusPlus0x ?
1216                      IsReturnCopyElidable(Context, FnRetType, RetValExp) :
1217                      false;
1218    // FIXME: Elidable
1219    (void)Elidable;
1220
1221    // In C++ the return statement is handled via a copy initialization.
1222    // the C version of which boils down to CheckSingleAssignmentConstraints.
1223    OwningExprResult Res = PerformCopyInitialization(
1224                             InitializedEntity::InitializeResult(ReturnLoc,
1225                                                                 FnRetType),
1226                             SourceLocation(),
1227                             Owned(RetValExp));
1228    if (Res.isInvalid()) {
1229      // FIXME: Cleanup temporaries here, anyway?
1230      return StmtError();
1231    }
1232
1233    RetValExp = Res.takeAs<Expr>();
1234    if (RetValExp)
1235      CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc);
1236  }
1237
1238  if (RetValExp)
1239    RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp);
1240  return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp));
1241}
1242
1243/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently
1244/// ignore "noop" casts in places where an lvalue is required by an inline asm.
1245/// We emulate this behavior when -fheinous-gnu-extensions is specified, but
1246/// provide a strong guidance to not use it.
1247///
1248/// This method checks to see if the argument is an acceptable l-value and
1249/// returns false if it is a case we can handle.
1250static bool CheckAsmLValue(const Expr *E, Sema &S) {
1251  // Type dependent expressions will be checked during instantiation.
1252  if (E->isTypeDependent())
1253    return false;
1254
1255  if (E->isLvalue(S.Context) == Expr::LV_Valid)
1256    return false;  // Cool, this is an lvalue.
1257
1258  // Okay, this is not an lvalue, but perhaps it is the result of a cast that we
1259  // are supposed to allow.
1260  const Expr *E2 = E->IgnoreParenNoopCasts(S.Context);
1261  if (E != E2 && E2->isLvalue(S.Context) == Expr::LV_Valid) {
1262    if (!S.getLangOptions().HeinousExtensions)
1263      S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue)
1264        << E->getSourceRange();
1265    else
1266      S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue)
1267        << E->getSourceRange();
1268    // Accept, even if we emitted an error diagnostic.
1269    return false;
1270  }
1271
1272  // None of the above, just randomly invalid non-lvalue.
1273  return true;
1274}
1275
1276
1277Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc,
1278                                          bool IsSimple,
1279                                          bool IsVolatile,
1280                                          unsigned NumOutputs,
1281                                          unsigned NumInputs,
1282                                          IdentifierInfo **Names,
1283                                          MultiExprArg constraints,
1284                                          MultiExprArg exprs,
1285                                          ExprArg asmString,
1286                                          MultiExprArg clobbers,
1287                                          SourceLocation RParenLoc,
1288                                          bool MSAsm) {
1289  unsigned NumClobbers = clobbers.size();
1290  StringLiteral **Constraints =
1291    reinterpret_cast<StringLiteral**>(constraints.get());
1292  Expr **Exprs = reinterpret_cast<Expr **>(exprs.get());
1293  StringLiteral *AsmString = cast<StringLiteral>((Expr *)asmString.get());
1294  StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get());
1295
1296  llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
1297
1298  // The parser verifies that there is a string literal here.
1299  if (AsmString->isWide())
1300    return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character)
1301      << AsmString->getSourceRange());
1302
1303  for (unsigned i = 0; i != NumOutputs; i++) {
1304    StringLiteral *Literal = Constraints[i];
1305    if (Literal->isWide())
1306      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
1307        << Literal->getSourceRange());
1308
1309    llvm::StringRef OutputName;
1310    if (Names[i])
1311      OutputName = Names[i]->getName();
1312
1313    TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName);
1314    if (!Context.Target.validateOutputConstraint(Info))
1315      return StmtError(Diag(Literal->getLocStart(),
1316                            diag::err_asm_invalid_output_constraint)
1317                       << Info.getConstraintStr());
1318
1319    // Check that the output exprs are valid lvalues.
1320    Expr *OutputExpr = Exprs[i];
1321    if (CheckAsmLValue(OutputExpr, *this)) {
1322      return StmtError(Diag(OutputExpr->getLocStart(),
1323                  diag::err_asm_invalid_lvalue_in_output)
1324        << OutputExpr->getSourceRange());
1325    }
1326
1327    OutputConstraintInfos.push_back(Info);
1328  }
1329
1330  llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
1331
1332  for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
1333    StringLiteral *Literal = Constraints[i];
1334    if (Literal->isWide())
1335      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
1336        << Literal->getSourceRange());
1337
1338    llvm::StringRef InputName;
1339    if (Names[i])
1340      InputName = Names[i]->getName();
1341
1342    TargetInfo::ConstraintInfo Info(Literal->getString(), InputName);
1343    if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(),
1344                                                NumOutputs, Info)) {
1345      return StmtError(Diag(Literal->getLocStart(),
1346                            diag::err_asm_invalid_input_constraint)
1347                       << Info.getConstraintStr());
1348    }
1349
1350    Expr *InputExpr = Exprs[i];
1351
1352    // Only allow void types for memory constraints.
1353    if (Info.allowsMemory() && !Info.allowsRegister()) {
1354      if (CheckAsmLValue(InputExpr, *this))
1355        return StmtError(Diag(InputExpr->getLocStart(),
1356                              diag::err_asm_invalid_lvalue_in_input)
1357                         << Info.getConstraintStr()
1358                         << InputExpr->getSourceRange());
1359    }
1360
1361    if (Info.allowsRegister()) {
1362      if (InputExpr->getType()->isVoidType()) {
1363        return StmtError(Diag(InputExpr->getLocStart(),
1364                              diag::err_asm_invalid_type_in_input)
1365          << InputExpr->getType() << Info.getConstraintStr()
1366          << InputExpr->getSourceRange());
1367      }
1368    }
1369
1370    DefaultFunctionArrayLvalueConversion(Exprs[i]);
1371
1372    InputConstraintInfos.push_back(Info);
1373  }
1374
1375  // Check that the clobbers are valid.
1376  for (unsigned i = 0; i != NumClobbers; i++) {
1377    StringLiteral *Literal = Clobbers[i];
1378    if (Literal->isWide())
1379      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
1380        << Literal->getSourceRange());
1381
1382    llvm::StringRef Clobber = Literal->getString();
1383
1384    if (!Context.Target.isValidGCCRegisterName(Clobber))
1385      return StmtError(Diag(Literal->getLocStart(),
1386                  diag::err_asm_unknown_register_name) << Clobber);
1387  }
1388
1389  constraints.release();
1390  exprs.release();
1391  asmString.release();
1392  clobbers.release();
1393  AsmStmt *NS =
1394    new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm,
1395                          NumOutputs, NumInputs, Names, Constraints, Exprs,
1396                          AsmString, NumClobbers, Clobbers, RParenLoc);
1397  // Validate the asm string, ensuring it makes sense given the operands we
1398  // have.
1399  llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces;
1400  unsigned DiagOffs;
1401  if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) {
1402    Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID)
1403           << AsmString->getSourceRange();
1404    DeleteStmt(NS);
1405    return StmtError();
1406  }
1407
1408  // Validate tied input operands for type mismatches.
1409  for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
1410    TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
1411
1412    // If this is a tied constraint, verify that the output and input have
1413    // either exactly the same type, or that they are int/ptr operands with the
1414    // same size (int/long, int*/long, are ok etc).
1415    if (!Info.hasTiedOperand()) continue;
1416
1417    unsigned TiedTo = Info.getTiedOperand();
1418    Expr *OutputExpr = Exprs[TiedTo];
1419    Expr *InputExpr = Exprs[i+NumOutputs];
1420    QualType InTy = InputExpr->getType();
1421    QualType OutTy = OutputExpr->getType();
1422    if (Context.hasSameType(InTy, OutTy))
1423      continue;  // All types can be tied to themselves.
1424
1425    // Int/ptr operands have some special cases that we allow.
1426    if ((OutTy->isIntegerType() || OutTy->isPointerType()) &&
1427        (InTy->isIntegerType() || InTy->isPointerType())) {
1428
1429      // They are ok if they are the same size.  Tying void* to int is ok if
1430      // they are the same size, for example.  This also allows tying void* to
1431      // int*.
1432      uint64_t OutSize = Context.getTypeSize(OutTy);
1433      uint64_t InSize = Context.getTypeSize(InTy);
1434      if (OutSize == InSize)
1435        continue;
1436
1437      // If the smaller input/output operand is not mentioned in the asm string,
1438      // then we can promote it and the asm string won't notice.  Check this
1439      // case now.
1440      bool SmallerValueMentioned = false;
1441      for (unsigned p = 0, e = Pieces.size(); p != e; ++p) {
1442        AsmStmt::AsmStringPiece &Piece = Pieces[p];
1443        if (!Piece.isOperand()) continue;
1444
1445        // If this is a reference to the input and if the input was the smaller
1446        // one, then we have to reject this asm.
1447        if (Piece.getOperandNo() == i+NumOutputs) {
1448          if (InSize < OutSize) {
1449            SmallerValueMentioned = true;
1450            break;
1451          }
1452        }
1453
1454        // If this is a reference to the input and if the input was the smaller
1455        // one, then we have to reject this asm.
1456        if (Piece.getOperandNo() == TiedTo) {
1457          if (InSize > OutSize) {
1458            SmallerValueMentioned = true;
1459            break;
1460          }
1461        }
1462      }
1463
1464      // If the smaller value wasn't mentioned in the asm string, and if the
1465      // output was a register, just extend the shorter one to the size of the
1466      // larger one.
1467      if (!SmallerValueMentioned &&
1468          OutputConstraintInfos[TiedTo].allowsRegister())
1469        continue;
1470    }
1471
1472    Diag(InputExpr->getLocStart(),
1473         diag::err_asm_tying_incompatible_types)
1474      << InTy << OutTy << OutputExpr->getSourceRange()
1475      << InputExpr->getSourceRange();
1476    DeleteStmt(NS);
1477    return StmtError();
1478  }
1479
1480  return Owned(NS);
1481}
1482
1483Action::OwningStmtResult
1484Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
1485                           SourceLocation RParen, DeclPtrTy Parm,
1486                           StmtArg Body, StmtArg catchList) {
1487  Stmt *CatchList = catchList.takeAs<Stmt>();
1488  ParmVarDecl *PVD = cast_or_null<ParmVarDecl>(Parm.getAs<Decl>());
1489
1490  // PVD == 0 implies @catch(...).
1491  if (PVD) {
1492    // If we already know the decl is invalid, reject it.
1493    if (PVD->isInvalidDecl())
1494      return StmtError();
1495
1496    if (!PVD->getType()->isObjCObjectPointerType())
1497      return StmtError(Diag(PVD->getLocation(),
1498                       diag::err_catch_param_not_objc_type));
1499    if (PVD->getType()->isObjCQualifiedIdType())
1500      return StmtError(Diag(PVD->getLocation(),
1501                       diag::err_illegal_qualifiers_on_catch_parm));
1502  }
1503
1504  ObjCAtCatchStmt *CS = new (Context) ObjCAtCatchStmt(AtLoc, RParen,
1505    PVD, Body.takeAs<Stmt>(), CatchList);
1506  return Owned(CatchList ? CatchList : CS);
1507}
1508
1509Action::OwningStmtResult
1510Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, StmtArg Body) {
1511  return Owned(new (Context) ObjCAtFinallyStmt(AtLoc,
1512                                           static_cast<Stmt*>(Body.release())));
1513}
1514
1515Action::OwningStmtResult
1516Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc,
1517                         StmtArg Try, StmtArg Catch, StmtArg Finally) {
1518  FunctionNeedsScopeChecking() = true;
1519  return Owned(new (Context) ObjCAtTryStmt(AtLoc, Try.takeAs<Stmt>(),
1520                                           Catch.takeAs<Stmt>(),
1521                                           Finally.takeAs<Stmt>()));
1522}
1523
1524Action::OwningStmtResult
1525Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg expr,Scope *CurScope) {
1526  Expr *ThrowExpr = expr.takeAs<Expr>();
1527  if (!ThrowExpr) {
1528    // @throw without an expression designates a rethrow (which much occur
1529    // in the context of an @catch clause).
1530    Scope *AtCatchParent = CurScope;
1531    while (AtCatchParent && !AtCatchParent->isAtCatchScope())
1532      AtCatchParent = AtCatchParent->getParent();
1533    if (!AtCatchParent)
1534      return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch));
1535  } else {
1536    QualType ThrowType = ThrowExpr->getType();
1537    // Make sure the expression type is an ObjC pointer or "void *".
1538    if (!ThrowType->isObjCObjectPointerType()) {
1539      const PointerType *PT = ThrowType->getAs<PointerType>();
1540      if (!PT || !PT->getPointeeType()->isVoidType())
1541        return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object)
1542                        << ThrowExpr->getType() << ThrowExpr->getSourceRange());
1543    }
1544  }
1545  return Owned(new (Context) ObjCAtThrowStmt(AtLoc, ThrowExpr));
1546}
1547
1548Action::OwningStmtResult
1549Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprArg SynchExpr,
1550                                  StmtArg SynchBody) {
1551  FunctionNeedsScopeChecking() = true;
1552
1553  // Make sure the expression type is an ObjC pointer or "void *".
1554  Expr *SyncExpr = static_cast<Expr*>(SynchExpr.get());
1555  if (!SyncExpr->getType()->isObjCObjectPointerType()) {
1556    const PointerType *PT = SyncExpr->getType()->getAs<PointerType>();
1557    if (!PT || !PT->getPointeeType()->isVoidType())
1558      return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object)
1559                       << SyncExpr->getType() << SyncExpr->getSourceRange());
1560  }
1561
1562  return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc,
1563                                                    SynchExpr.takeAs<Stmt>(),
1564                                                    SynchBody.takeAs<Stmt>()));
1565}
1566
1567/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
1568/// and creates a proper catch handler from them.
1569Action::OwningStmtResult
1570Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclPtrTy ExDecl,
1571                         StmtArg HandlerBlock) {
1572  // There's nothing to test that ActOnExceptionDecl didn't already test.
1573  return Owned(new (Context) CXXCatchStmt(CatchLoc,
1574                                  cast_or_null<VarDecl>(ExDecl.getAs<Decl>()),
1575                                          HandlerBlock.takeAs<Stmt>()));
1576}
1577
1578class TypeWithHandler {
1579  QualType t;
1580  CXXCatchStmt *stmt;
1581public:
1582  TypeWithHandler(const QualType &type, CXXCatchStmt *statement)
1583  : t(type), stmt(statement) {}
1584
1585  // An arbitrary order is fine as long as it places identical
1586  // types next to each other.
1587  bool operator<(const TypeWithHandler &y) const {
1588    if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr())
1589      return true;
1590    if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr())
1591      return false;
1592    else
1593      return getTypeSpecStartLoc() < y.getTypeSpecStartLoc();
1594  }
1595
1596  bool operator==(const TypeWithHandler& other) const {
1597    return t == other.t;
1598  }
1599
1600  QualType getQualType() const { return t; }
1601  CXXCatchStmt *getCatchStmt() const { return stmt; }
1602  SourceLocation getTypeSpecStartLoc() const {
1603    return stmt->getExceptionDecl()->getTypeSpecStartLoc();
1604  }
1605};
1606
1607/// ActOnCXXTryBlock - Takes a try compound-statement and a number of
1608/// handlers and creates a try statement from them.
1609Action::OwningStmtResult
1610Sema::ActOnCXXTryBlock(SourceLocation TryLoc, StmtArg TryBlock,
1611                       MultiStmtArg RawHandlers) {
1612  unsigned NumHandlers = RawHandlers.size();
1613  assert(NumHandlers > 0 &&
1614         "The parser shouldn't call this if there are no handlers.");
1615  Stmt **Handlers = reinterpret_cast<Stmt**>(RawHandlers.get());
1616
1617  llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers;
1618
1619  for (unsigned i = 0; i < NumHandlers; ++i) {
1620    CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]);
1621    if (!Handler->getExceptionDecl()) {
1622      if (i < NumHandlers - 1)
1623        return StmtError(Diag(Handler->getLocStart(),
1624                              diag::err_early_catch_all));
1625
1626      continue;
1627    }
1628
1629    const QualType CaughtType = Handler->getCaughtType();
1630    const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType);
1631    TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler));
1632  }
1633
1634  // Detect handlers for the same type as an earlier one.
1635  if (NumHandlers > 1) {
1636    llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end());
1637
1638    TypeWithHandler prev = TypesWithHandlers[0];
1639    for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) {
1640      TypeWithHandler curr = TypesWithHandlers[i];
1641
1642      if (curr == prev) {
1643        Diag(curr.getTypeSpecStartLoc(),
1644             diag::warn_exception_caught_by_earlier_handler)
1645          << curr.getCatchStmt()->getCaughtType().getAsString();
1646        Diag(prev.getTypeSpecStartLoc(),
1647             diag::note_previous_exception_handler)
1648          << prev.getCatchStmt()->getCaughtType().getAsString();
1649      }
1650
1651      prev = curr;
1652    }
1653  }
1654
1655  // FIXME: We should detect handlers that cannot catch anything because an
1656  // earlier handler catches a superclass. Need to find a method that is not
1657  // quadratic for this.
1658  // Neither of these are explicitly forbidden, but every compiler detects them
1659  // and warns.
1660
1661  FunctionNeedsScopeChecking() = true;
1662  RawHandlers.release();
1663  return Owned(CXXTryStmt::Create(Context, TryLoc,
1664                                  static_cast<Stmt*>(TryBlock.release()),
1665                                  Handlers, NumHandlers));
1666}
1667