SemaStmt.cpp revision 12f78a6741a4cb3d904340f8d3d2714568b50e7a 
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 "clang/Sema/SemaInternal.h"
15#include "clang/Sema/Scope.h"
16#include "clang/Sema/ScopeInfo.h"
17#include "clang/Sema/Initialization.h"
18#include "clang/AST/APValue.h"
19#include "clang/AST/ASTContext.h"
20#include "clang/AST/DeclObjC.h"
21#include "clang/AST/ExprCXX.h"
22#include "clang/AST/ExprObjC.h"
23#include "clang/AST/StmtObjC.h"
24#include "clang/AST/StmtCXX.h"
25#include "clang/AST/TypeLoc.h"
26#include "clang/Lex/Preprocessor.h"
27#include "clang/Basic/TargetInfo.h"
28#include "llvm/ADT/STLExtras.h"
29#include "llvm/ADT/SmallVector.h"
30using namespace clang;
31using namespace sema;
32
33StmtResult Sema::ActOnExprStmt(FullExprArg expr) {
34  Expr *E = expr.get();
35  assert(E && "ActOnExprStmt(): missing expression");
36  // C99 6.8.3p2: The expression in an expression statement is evaluated as a
37  // void expression for its side effects.  Conversion to void allows any
38  // operand, even incomplete types.
39
40  // Same thing in for stmt first clause (when expr) and third clause.
41  return Owned(static_cast<Stmt*>(E));
42}
43
44
45StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, bool LeadingEmptyMacro) {
46  return Owned(new (Context) NullStmt(SemiLoc, LeadingEmptyMacro));
47}
48
49StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg,
50                                           SourceLocation StartLoc,
51                                           SourceLocation EndLoc) {
52  DeclGroupRef DG = dg.getAsVal<DeclGroupRef>();
53
54  // If we have an invalid decl, just return an error.
55  if (DG.isNull()) return StmtError();
56
57  return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc));
58}
59
60void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
61  DeclGroupRef DG = dg.getAsVal<DeclGroupRef>();
62
63  // If we have an invalid decl, just return.
64  if (DG.isNull() || !DG.isSingleDecl()) return;
65  // suppress any potential 'unused variable' warning.
66  DG.getSingleDecl()->setUsed();
67}
68
69void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
70  if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S))
71    return DiagnoseUnusedExprResult(Label->getSubStmt());
72
73  const Expr *E = dyn_cast_or_null<Expr>(S);
74  if (!E)
75    return;
76
77  if (E->isBoundMemberFunction(Context)) {
78    Diag(E->getLocStart(), diag::err_invalid_use_of_bound_member_func)
79      << E->getSourceRange();
80    return;
81  }
82
83  SourceLocation Loc;
84  SourceRange R1, R2;
85  if (!E->isUnusedResultAWarning(Loc, R1, R2, Context))
86    return;
87
88  // Okay, we have an unused result.  Depending on what the base expression is,
89  // we might want to make a more specific diagnostic.  Check for one of these
90  // cases now.
91  unsigned DiagID = diag::warn_unused_expr;
92  if (const CXXExprWithTemporaries *Temps = dyn_cast<CXXExprWithTemporaries>(E))
93    E = Temps->getSubExpr();
94
95  E = E->IgnoreParens();
96  if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
97    if (E->getType()->isVoidType())
98      return;
99
100    // If the callee has attribute pure, const, or warn_unused_result, warn with
101    // a more specific message to make it clear what is happening.
102    if (const Decl *FD = CE->getCalleeDecl()) {
103      if (FD->getAttr<WarnUnusedResultAttr>()) {
104        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result";
105        return;
106      }
107      if (FD->getAttr<PureAttr>()) {
108        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure";
109        return;
110      }
111      if (FD->getAttr<ConstAttr>()) {
112        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const";
113        return;
114      }
115    }
116  } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) {
117    const ObjCMethodDecl *MD = ME->getMethodDecl();
118    if (MD && MD->getAttr<WarnUnusedResultAttr>()) {
119      Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result";
120      return;
121    }
122  } else if (isa<ObjCPropertyRefExpr>(E)) {
123    DiagID = diag::warn_unused_property_expr;
124  } else if (const CXXFunctionalCastExpr *FC
125                                       = dyn_cast<CXXFunctionalCastExpr>(E)) {
126    if (isa<CXXConstructExpr>(FC->getSubExpr()) ||
127        isa<CXXTemporaryObjectExpr>(FC->getSubExpr()))
128      return;
129  }
130  // Diagnose "(void*) blah" as a typo for "(void) blah".
131  else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) {
132    TypeSourceInfo *TI = CE->getTypeInfoAsWritten();
133    QualType T = TI->getType();
134
135    // We really do want to use the non-canonical type here.
136    if (T == Context.VoidPtrTy) {
137      PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc());
138
139      Diag(Loc, diag::warn_unused_voidptr)
140        << FixItHint::CreateRemoval(TL.getStarLoc());
141      return;
142    }
143  }
144
145  DiagRuntimeBehavior(Loc, PDiag(DiagID) << R1 << R2);
146}
147
148StmtResult
149Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
150                        MultiStmtArg elts, bool isStmtExpr) {
151  unsigned NumElts = elts.size();
152  Stmt **Elts = reinterpret_cast<Stmt**>(elts.release());
153  // If we're in C89 mode, check that we don't have any decls after stmts.  If
154  // so, emit an extension diagnostic.
155  if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) {
156    // Note that __extension__ can be around a decl.
157    unsigned i = 0;
158    // Skip over all declarations.
159    for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i)
160      /*empty*/;
161
162    // We found the end of the list or a statement.  Scan for another declstmt.
163    for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i)
164      /*empty*/;
165
166    if (i != NumElts) {
167      Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin();
168      Diag(D->getLocation(), diag::ext_mixed_decls_code);
169    }
170  }
171  // Warn about unused expressions in statements.
172  for (unsigned i = 0; i != NumElts; ++i) {
173    // Ignore statements that are last in a statement expression.
174    if (isStmtExpr && i == NumElts - 1)
175      continue;
176
177    DiagnoseUnusedExprResult(Elts[i]);
178  }
179
180  return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R));
181}
182
183StmtResult
184Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal,
185                    SourceLocation DotDotDotLoc, Expr *RHSVal,
186                    SourceLocation ColonLoc) {
187  assert((LHSVal != 0) && "missing expression in case statement");
188
189  // C99 6.8.4.2p3: The expression shall be an integer constant.
190  // However, GCC allows any evaluatable integer expression.
191  if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() &&
192      VerifyIntegerConstantExpression(LHSVal))
193    return StmtError();
194
195  // GCC extension: The expression shall be an integer constant.
196
197  if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() &&
198      VerifyIntegerConstantExpression(RHSVal)) {
199    RHSVal = 0;  // Recover by just forgetting about it.
200  }
201
202  if (getCurFunction()->SwitchStack.empty()) {
203    Diag(CaseLoc, diag::err_case_not_in_switch);
204    return StmtError();
205  }
206
207  CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc,
208                                        ColonLoc);
209  getCurFunction()->SwitchStack.back()->addSwitchCase(CS);
210  return Owned(CS);
211}
212
213/// ActOnCaseStmtBody - This installs a statement as the body of a case.
214void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) {
215  CaseStmt *CS = static_cast<CaseStmt*>(caseStmt);
216  CS->setSubStmt(SubStmt);
217}
218
219StmtResult
220Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
221                       Stmt *SubStmt, Scope *CurScope) {
222  if (getCurFunction()->SwitchStack.empty()) {
223    Diag(DefaultLoc, diag::err_default_not_in_switch);
224    return Owned(SubStmt);
225  }
226
227  DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
228  getCurFunction()->SwitchStack.back()->addSwitchCase(DS);
229  return Owned(DS);
230}
231
232StmtResult
233Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II,
234                     SourceLocation ColonLoc, Stmt *SubStmt,
235                     const AttributeList *Attr) {
236  // According to GCC docs, "the only attribute that makes sense after a label
237  // is 'unused'".
238  bool HasUnusedAttr = false;
239  for ( ; Attr; Attr = Attr->getNext()) {
240    if (Attr->getKind() == AttributeList::AT_unused) {
241      HasUnusedAttr = true;
242    } else {
243      Diag(Attr->getLoc(), diag::warn_label_attribute_not_unused);
244      Attr->setInvalid(true);
245    }
246  }
247
248  return ActOnLabelStmt(IdentLoc, II, ColonLoc, SubStmt, HasUnusedAttr);
249}
250
251StmtResult
252Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II,
253                     SourceLocation ColonLoc, Stmt *SubStmt,
254                     bool HasUnusedAttr) {
255  // Look up the record for this label identifier.
256  LabelStmt *&LabelDecl = getCurFunction()->LabelMap[II];
257
258  // If not forward referenced or defined already, just create a new LabelStmt.
259  if (LabelDecl == 0)
260    return Owned(LabelDecl = new (Context) LabelStmt(IdentLoc, II, SubStmt,
261                                                     HasUnusedAttr));
262
263  assert(LabelDecl->getID() == II && "Label mismatch!");
264
265  // Otherwise, this label was either forward reference or multiply defined.  If
266  // multiply defined, reject it now.
267  if (LabelDecl->getSubStmt()) {
268    Diag(IdentLoc, diag::err_redefinition_of_label) << LabelDecl->getID();
269    Diag(LabelDecl->getIdentLoc(), diag::note_previous_definition);
270    return Owned(SubStmt);
271  }
272
273  // Otherwise, this label was forward declared, and we just found its real
274  // definition.  Fill in the forward definition and return it.
275  LabelDecl->setIdentLoc(IdentLoc);
276  LabelDecl->setSubStmt(SubStmt);
277  LabelDecl->setUnusedAttribute(HasUnusedAttr);
278  return Owned(LabelDecl);
279}
280
281StmtResult
282Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar,
283                  Stmt *thenStmt, SourceLocation ElseLoc,
284                  Stmt *elseStmt) {
285  ExprResult CondResult(CondVal.release());
286
287  VarDecl *ConditionVar = 0;
288  if (CondVar) {
289    ConditionVar = cast<VarDecl>(CondVar);
290    CondResult = CheckConditionVariable(ConditionVar, IfLoc, true);
291    if (CondResult.isInvalid())
292      return StmtError();
293  }
294  Expr *ConditionExpr = CondResult.takeAs<Expr>();
295  if (!ConditionExpr)
296    return StmtError();
297
298  DiagnoseUnusedExprResult(thenStmt);
299
300  // Warn if the if block has a null body without an else value.
301  // this helps prevent bugs due to typos, such as
302  // if (condition);
303  //   do_stuff();
304  //
305  if (!elseStmt) {
306    if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt))
307      // But do not warn if the body is a macro that expands to nothing, e.g:
308      //
309      // #define CALL(x)
310      // if (condition)
311      //   CALL(0);
312      //
313      if (!stmt->hasLeadingEmptyMacro())
314        Diag(stmt->getSemiLoc(), diag::warn_empty_if_body);
315  }
316
317  DiagnoseUnusedExprResult(elseStmt);
318
319  return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr,
320                                    thenStmt, ElseLoc, elseStmt));
321}
322
323/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have
324/// the specified width and sign.  If an overflow occurs, detect it and emit
325/// the specified diagnostic.
326void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val,
327                                              unsigned NewWidth, bool NewSign,
328                                              SourceLocation Loc,
329                                              unsigned DiagID) {
330  // Perform a conversion to the promoted condition type if needed.
331  if (NewWidth > Val.getBitWidth()) {
332    // If this is an extension, just do it.
333    Val.extend(NewWidth);
334    Val.setIsSigned(NewSign);
335
336    // If the input was signed and negative and the output is
337    // unsigned, don't bother to warn: this is implementation-defined
338    // behavior.
339    // FIXME: Introduce a second, default-ignored warning for this case?
340  } else if (NewWidth < Val.getBitWidth()) {
341    // If this is a truncation, check for overflow.
342    llvm::APSInt ConvVal(Val);
343    ConvVal.trunc(NewWidth);
344    ConvVal.setIsSigned(NewSign);
345    ConvVal.extend(Val.getBitWidth());
346    ConvVal.setIsSigned(Val.isSigned());
347    if (ConvVal != Val)
348      Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10);
349
350    // Regardless of whether a diagnostic was emitted, really do the
351    // truncation.
352    Val.trunc(NewWidth);
353    Val.setIsSigned(NewSign);
354  } else if (NewSign != Val.isSigned()) {
355    // Convert the sign to match the sign of the condition.  This can cause
356    // overflow as well: unsigned(INTMIN)
357    // We don't diagnose this overflow, because it is implementation-defined
358    // behavior.
359    // FIXME: Introduce a second, default-ignored warning for this case?
360    llvm::APSInt OldVal(Val);
361    Val.setIsSigned(NewSign);
362  }
363}
364
365namespace {
366  struct CaseCompareFunctor {
367    bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
368                    const llvm::APSInt &RHS) {
369      return LHS.first < RHS;
370    }
371    bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
372                    const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
373      return LHS.first < RHS.first;
374    }
375    bool operator()(const llvm::APSInt &LHS,
376                    const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
377      return LHS < RHS.first;
378    }
379  };
380}
381
382/// CmpCaseVals - Comparison predicate for sorting case values.
383///
384static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
385                        const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
386  if (lhs.first < rhs.first)
387    return true;
388
389  if (lhs.first == rhs.first &&
390      lhs.second->getCaseLoc().getRawEncoding()
391       < rhs.second->getCaseLoc().getRawEncoding())
392    return true;
393  return false;
394}
395
396/// CmpEnumVals - Comparison predicate for sorting enumeration values.
397///
398static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
399                        const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
400{
401  return lhs.first < rhs.first;
402}
403
404/// EqEnumVals - Comparison preficate for uniqing enumeration values.
405///
406static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
407                       const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
408{
409  return lhs.first == rhs.first;
410}
411
412/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
413/// potentially integral-promoted expression @p expr.
414static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) {
415  if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) {
416    const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr();
417    QualType TypeBeforePromotion = ExprBeforePromotion->getType();
418    if (TypeBeforePromotion->isIntegralOrEnumerationType()) {
419      return TypeBeforePromotion;
420    }
421  }
422  return expr->getType();
423}
424
425StmtResult
426Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond,
427                             Decl *CondVar) {
428  ExprResult CondResult;
429
430  VarDecl *ConditionVar = 0;
431  if (CondVar) {
432    ConditionVar = cast<VarDecl>(CondVar);
433    CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false);
434    if (CondResult.isInvalid())
435      return StmtError();
436
437    Cond = CondResult.release();
438  }
439
440  if (!Cond)
441    return StmtError();
442
443  CondResult
444    = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond,
445                          PDiag(diag::err_typecheck_statement_requires_integer),
446                                   PDiag(diag::err_switch_incomplete_class_type)
447                                     << Cond->getSourceRange(),
448                                   PDiag(diag::err_switch_explicit_conversion),
449                                         PDiag(diag::note_switch_conversion),
450                                   PDiag(diag::err_switch_multiple_conversions),
451                                         PDiag(diag::note_switch_conversion),
452                                         PDiag(0));
453  if (CondResult.isInvalid()) return StmtError();
454  Cond = CondResult.take();
455
456  if (!CondVar) {
457    CheckImplicitConversions(Cond, SwitchLoc);
458    CondResult = MaybeCreateCXXExprWithTemporaries(Cond);
459    if (CondResult.isInvalid())
460      return StmtError();
461    Cond = CondResult.take();
462  }
463
464  getCurFunction()->setHasBranchIntoScope();
465
466  SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond);
467  getCurFunction()->SwitchStack.push_back(SS);
468  return Owned(SS);
469}
470
471static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) {
472  if (Val.getBitWidth() < BitWidth)
473    Val.extend(BitWidth);
474  else if (Val.getBitWidth() > BitWidth)
475    Val.trunc(BitWidth);
476  Val.setIsSigned(IsSigned);
477}
478
479StmtResult
480Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
481                            Stmt *BodyStmt) {
482  SwitchStmt *SS = cast<SwitchStmt>(Switch);
483  assert(SS == getCurFunction()->SwitchStack.back() &&
484         "switch stack missing push/pop!");
485
486  SS->setBody(BodyStmt, SwitchLoc);
487  getCurFunction()->SwitchStack.pop_back();
488
489  if (SS->getCond() == 0)
490    return StmtError();
491
492  Expr *CondExpr = SS->getCond();
493  Expr *CondExprBeforePromotion = CondExpr;
494  QualType CondTypeBeforePromotion =
495      GetTypeBeforeIntegralPromotion(CondExpr);
496
497  // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
498  UsualUnaryConversions(CondExpr);
499  QualType CondType = CondExpr->getType();
500  SS->setCond(CondExpr);
501
502  // C++ 6.4.2.p2:
503  // Integral promotions are performed (on the switch condition).
504  //
505  // A case value unrepresentable by the original switch condition
506  // type (before the promotion) doesn't make sense, even when it can
507  // be represented by the promoted type.  Therefore we need to find
508  // the pre-promotion type of the switch condition.
509  if (!CondExpr->isTypeDependent()) {
510    // We have already converted the expression to an integral or enumeration
511    // type, when we started the switch statement. If we don't have an
512    // appropriate type now, just return an error.
513    if (!CondType->isIntegralOrEnumerationType())
514      return StmtError();
515
516    if (CondExpr->isKnownToHaveBooleanValue()) {
517      // switch(bool_expr) {...} is often a programmer error, e.g.
518      //   switch(n && mask) { ... }  // Doh - should be "n & mask".
519      // One can always use an if statement instead of switch(bool_expr).
520      Diag(SwitchLoc, diag::warn_bool_switch_condition)
521          << CondExpr->getSourceRange();
522    }
523  }
524
525  // Get the bitwidth of the switched-on value before promotions.  We must
526  // convert the integer case values to this width before comparison.
527  bool HasDependentValue
528    = CondExpr->isTypeDependent() || CondExpr->isValueDependent();
529  unsigned CondWidth
530    = HasDependentValue? 0
531      : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion));
532  bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType();
533
534  // Accumulate all of the case values in a vector so that we can sort them
535  // and detect duplicates.  This vector contains the APInt for the case after
536  // it has been converted to the condition type.
537  typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
538  CaseValsTy CaseVals;
539
540  // Keep track of any GNU case ranges we see.  The APSInt is the low value.
541  typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy;
542  CaseRangesTy CaseRanges;
543
544  DefaultStmt *TheDefaultStmt = 0;
545
546  bool CaseListIsErroneous = false;
547
548  for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
549       SC = SC->getNextSwitchCase()) {
550
551    if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) {
552      if (TheDefaultStmt) {
553        Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
554        Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev);
555
556        // FIXME: Remove the default statement from the switch block so that
557        // we'll return a valid AST.  This requires recursing down the AST and
558        // finding it, not something we are set up to do right now.  For now,
559        // just lop the entire switch stmt out of the AST.
560        CaseListIsErroneous = true;
561      }
562      TheDefaultStmt = DS;
563
564    } else {
565      CaseStmt *CS = cast<CaseStmt>(SC);
566
567      // We already verified that the expression has a i-c-e value (C99
568      // 6.8.4.2p3) - get that value now.
569      Expr *Lo = CS->getLHS();
570
571      if (Lo->isTypeDependent() || Lo->isValueDependent()) {
572        HasDependentValue = true;
573        break;
574      }
575
576      llvm::APSInt LoVal = Lo->EvaluateAsInt(Context);
577
578      // Convert the value to the same width/sign as the condition.
579      ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned,
580                                         Lo->getLocStart(),
581                                         diag::warn_case_value_overflow);
582
583      // If the LHS is not the same type as the condition, insert an implicit
584      // cast.
585      ImpCastExprToType(Lo, CondType, CK_IntegralCast);
586      CS->setLHS(Lo);
587
588      // If this is a case range, remember it in CaseRanges, otherwise CaseVals.
589      if (CS->getRHS()) {
590        if (CS->getRHS()->isTypeDependent() ||
591            CS->getRHS()->isValueDependent()) {
592          HasDependentValue = true;
593          break;
594        }
595        CaseRanges.push_back(std::make_pair(LoVal, CS));
596      } else
597        CaseVals.push_back(std::make_pair(LoVal, CS));
598    }
599  }
600
601  if (!HasDependentValue) {
602    // If we don't have a default statement, check whether the
603    // condition is constant.
604    llvm::APSInt ConstantCondValue;
605    bool HasConstantCond = false;
606    bool ShouldCheckConstantCond = false;
607    if (!HasDependentValue && !TheDefaultStmt) {
608      Expr::EvalResult Result;
609      HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context);
610      if (HasConstantCond) {
611        assert(Result.Val.isInt() && "switch condition evaluated to non-int");
612        ConstantCondValue = Result.Val.getInt();
613        ShouldCheckConstantCond = true;
614
615        assert(ConstantCondValue.getBitWidth() == CondWidth &&
616               ConstantCondValue.isSigned() == CondIsSigned);
617      }
618    }
619
620    // Sort all the scalar case values so we can easily detect duplicates.
621    std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals);
622
623    if (!CaseVals.empty()) {
624      for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) {
625        if (ShouldCheckConstantCond &&
626            CaseVals[i].first == ConstantCondValue)
627          ShouldCheckConstantCond = false;
628
629        if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) {
630          // If we have a duplicate, report it.
631          Diag(CaseVals[i].second->getLHS()->getLocStart(),
632               diag::err_duplicate_case) << CaseVals[i].first.toString(10);
633          Diag(CaseVals[i-1].second->getLHS()->getLocStart(),
634               diag::note_duplicate_case_prev);
635          // FIXME: We really want to remove the bogus case stmt from the
636          // substmt, but we have no way to do this right now.
637          CaseListIsErroneous = true;
638        }
639      }
640    }
641
642    // Detect duplicate case ranges, which usually don't exist at all in
643    // the first place.
644    if (!CaseRanges.empty()) {
645      // Sort all the case ranges by their low value so we can easily detect
646      // overlaps between ranges.
647      std::stable_sort(CaseRanges.begin(), CaseRanges.end());
648
649      // Scan the ranges, computing the high values and removing empty ranges.
650      std::vector<llvm::APSInt> HiVals;
651      for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
652        llvm::APSInt &LoVal = CaseRanges[i].first;
653        CaseStmt *CR = CaseRanges[i].second;
654        Expr *Hi = CR->getRHS();
655        llvm::APSInt HiVal = Hi->EvaluateAsInt(Context);
656
657        // Convert the value to the same width/sign as the condition.
658        ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned,
659                                           Hi->getLocStart(),
660                                           diag::warn_case_value_overflow);
661
662        // If the LHS is not the same type as the condition, insert an implicit
663        // cast.
664        ImpCastExprToType(Hi, CondType, CK_IntegralCast);
665        CR->setRHS(Hi);
666
667        // If the low value is bigger than the high value, the case is empty.
668        if (LoVal > HiVal) {
669          Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range)
670            << SourceRange(CR->getLHS()->getLocStart(),
671                           Hi->getLocEnd());
672          CaseRanges.erase(CaseRanges.begin()+i);
673          --i, --e;
674          continue;
675        }
676
677        if (ShouldCheckConstantCond &&
678            LoVal <= ConstantCondValue &&
679            ConstantCondValue <= HiVal)
680          ShouldCheckConstantCond = false;
681
682        HiVals.push_back(HiVal);
683      }
684
685      // Rescan the ranges, looking for overlap with singleton values and other
686      // ranges.  Since the range list is sorted, we only need to compare case
687      // ranges with their neighbors.
688      for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
689        llvm::APSInt &CRLo = CaseRanges[i].first;
690        llvm::APSInt &CRHi = HiVals[i];
691        CaseStmt *CR = CaseRanges[i].second;
692
693        // Check to see whether the case range overlaps with any
694        // singleton cases.
695        CaseStmt *OverlapStmt = 0;
696        llvm::APSInt OverlapVal(32);
697
698        // Find the smallest value >= the lower bound.  If I is in the
699        // case range, then we have overlap.
700        CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(),
701                                                  CaseVals.end(), CRLo,
702                                                  CaseCompareFunctor());
703        if (I != CaseVals.end() && I->first < CRHi) {
704          OverlapVal  = I->first;   // Found overlap with scalar.
705          OverlapStmt = I->second;
706        }
707
708        // Find the smallest value bigger than the upper bound.
709        I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor());
710        if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
711          OverlapVal  = (I-1)->first;      // Found overlap with scalar.
712          OverlapStmt = (I-1)->second;
713        }
714
715        // Check to see if this case stmt overlaps with the subsequent
716        // case range.
717        if (i && CRLo <= HiVals[i-1]) {
718          OverlapVal  = HiVals[i-1];       // Found overlap with range.
719          OverlapStmt = CaseRanges[i-1].second;
720        }
721
722        if (OverlapStmt) {
723          // If we have a duplicate, report it.
724          Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case)
725            << OverlapVal.toString(10);
726          Diag(OverlapStmt->getLHS()->getLocStart(),
727               diag::note_duplicate_case_prev);
728          // FIXME: We really want to remove the bogus case stmt from the
729          // substmt, but we have no way to do this right now.
730          CaseListIsErroneous = true;
731        }
732      }
733    }
734
735    // Complain if we have a constant condition and we didn't find a match.
736    if (!CaseListIsErroneous && ShouldCheckConstantCond) {
737      // TODO: it would be nice if we printed enums as enums, chars as
738      // chars, etc.
739      Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition)
740        << ConstantCondValue.toString(10)
741        << CondExpr->getSourceRange();
742    }
743
744    // Check to see if switch is over an Enum and handles all of its
745    // values.  We only issue a warning if there is not 'default:', but
746    // we still do the analysis to preserve this information in the AST
747    // (which can be used by flow-based analyes).
748    //
749    const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>();
750
751    // If switch has default case, then ignore it.
752    if (!CaseListIsErroneous  && !HasConstantCond && ET) {
753      const EnumDecl *ED = ET->getDecl();
754      typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy;
755      EnumValsTy EnumVals;
756
757      // Gather all enum values, set their type and sort them,
758      // allowing easier comparison with CaseVals.
759      for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin();
760           EDI != ED->enumerator_end(); ++EDI) {
761        llvm::APSInt Val = EDI->getInitVal();
762        AdjustAPSInt(Val, CondWidth, CondIsSigned);
763        EnumVals.push_back(std::make_pair(Val, *EDI));
764      }
765      std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals);
766      EnumValsTy::iterator EIend =
767        std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals);
768
769      // See which case values aren't in enum.
770      // TODO: we might want to check whether case values are out of the
771      // enum even if we don't want to check whether all cases are handled.
772      if (!TheDefaultStmt) {
773        EnumValsTy::const_iterator EI = EnumVals.begin();
774        for (CaseValsTy::const_iterator CI = CaseVals.begin();
775             CI != CaseVals.end(); CI++) {
776          while (EI != EIend && EI->first < CI->first)
777            EI++;
778          if (EI == EIend || EI->first > CI->first)
779            Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum)
780              << ED->getDeclName();
781        }
782        // See which of case ranges aren't in enum
783        EI = EnumVals.begin();
784        for (CaseRangesTy::const_iterator RI = CaseRanges.begin();
785             RI != CaseRanges.end() && EI != EIend; RI++) {
786          while (EI != EIend && EI->first < RI->first)
787            EI++;
788
789          if (EI == EIend || EI->first != RI->first) {
790            Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum)
791              << ED->getDeclName();
792          }
793
794          llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context);
795          AdjustAPSInt(Hi, CondWidth, CondIsSigned);
796          while (EI != EIend && EI->first < Hi)
797            EI++;
798          if (EI == EIend || EI->first != Hi)
799            Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum)
800              << ED->getDeclName();
801        }
802      }
803
804      // Check which enum vals aren't in switch
805      CaseValsTy::const_iterator CI = CaseVals.begin();
806      CaseRangesTy::const_iterator RI = CaseRanges.begin();
807      bool hasCasesNotInSwitch = false;
808
809      llvm::SmallVector<DeclarationName,8> UnhandledNames;
810
811      for (EnumValsTy::const_iterator EI = EnumVals.begin(); EI != EIend; EI++){
812        // Drop unneeded case values
813        llvm::APSInt CIVal;
814        while (CI != CaseVals.end() && CI->first < EI->first)
815          CI++;
816
817        if (CI != CaseVals.end() && CI->first == EI->first)
818          continue;
819
820        // Drop unneeded case ranges
821        for (; RI != CaseRanges.end(); RI++) {
822          llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context);
823          AdjustAPSInt(Hi, CondWidth, CondIsSigned);
824          if (EI->first <= Hi)
825            break;
826        }
827
828        if (RI == CaseRanges.end() || EI->first < RI->first) {
829          hasCasesNotInSwitch = true;
830          if (!TheDefaultStmt)
831            UnhandledNames.push_back(EI->second->getDeclName());
832        }
833      }
834
835      // Produce a nice diagnostic if multiple values aren't handled.
836      switch (UnhandledNames.size()) {
837      case 0: break;
838      case 1:
839        Diag(CondExpr->getExprLoc(), diag::warn_missing_case1)
840          << UnhandledNames[0];
841        break;
842      case 2:
843        Diag(CondExpr->getExprLoc(), diag::warn_missing_case2)
844          << UnhandledNames[0] << UnhandledNames[1];
845        break;
846      case 3:
847        Diag(CondExpr->getExprLoc(), diag::warn_missing_case3)
848          << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2];
849        break;
850      default:
851        Diag(CondExpr->getExprLoc(), diag::warn_missing_cases)
852          << (unsigned)UnhandledNames.size()
853          << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2];
854        break;
855      }
856
857      if (!hasCasesNotInSwitch)
858        SS->setAllEnumCasesCovered();
859    }
860  }
861
862  // FIXME: If the case list was broken is some way, we don't have a good system
863  // to patch it up.  Instead, just return the whole substmt as broken.
864  if (CaseListIsErroneous)
865    return StmtError();
866
867  return Owned(SS);
868}
869
870StmtResult
871Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond,
872                     Decl *CondVar, Stmt *Body) {
873  ExprResult CondResult(Cond.release());
874
875  VarDecl *ConditionVar = 0;
876  if (CondVar) {
877    ConditionVar = cast<VarDecl>(CondVar);
878    CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true);
879    if (CondResult.isInvalid())
880      return StmtError();
881  }
882  Expr *ConditionExpr = CondResult.take();
883  if (!ConditionExpr)
884    return StmtError();
885
886  DiagnoseUnusedExprResult(Body);
887
888  return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr,
889                                       Body, WhileLoc));
890}
891
892StmtResult
893Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
894                  SourceLocation WhileLoc, SourceLocation CondLParen,
895                  Expr *Cond, SourceLocation CondRParen) {
896  assert(Cond && "ActOnDoStmt(): missing expression");
897
898  if (CheckBooleanCondition(Cond, DoLoc))
899    return StmtError();
900
901  CheckImplicitConversions(Cond, DoLoc);
902  ExprResult CondResult = MaybeCreateCXXExprWithTemporaries(Cond);
903  if (CondResult.isInvalid())
904    return StmtError();
905  Cond = CondResult.take();
906
907  DiagnoseUnusedExprResult(Body);
908
909  return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen));
910}
911
912StmtResult
913Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
914                   Stmt *First, FullExprArg second, Decl *secondVar,
915                   FullExprArg third,
916                   SourceLocation RParenLoc, Stmt *Body) {
917  if (!getLangOptions().CPlusPlus) {
918    if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) {
919      // C99 6.8.5p3: The declaration part of a 'for' statement shall only
920      // declare identifiers for objects having storage class 'auto' or
921      // 'register'.
922      for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end();
923           DI!=DE; ++DI) {
924        VarDecl *VD = dyn_cast<VarDecl>(*DI);
925        if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage())
926          VD = 0;
927        if (VD == 0)
928          Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for);
929        // FIXME: mark decl erroneous!
930      }
931    }
932  }
933
934  ExprResult SecondResult(second.release());
935  VarDecl *ConditionVar = 0;
936  if (secondVar) {
937    ConditionVar = cast<VarDecl>(secondVar);
938    SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true);
939    if (SecondResult.isInvalid())
940      return StmtError();
941  }
942
943  Expr *Third  = third.release().takeAs<Expr>();
944
945  DiagnoseUnusedExprResult(First);
946  DiagnoseUnusedExprResult(Third);
947  DiagnoseUnusedExprResult(Body);
948
949  return Owned(new (Context) ForStmt(Context, First,
950                                     SecondResult.take(), ConditionVar,
951                                     Third, Body, ForLoc, LParenLoc,
952                                     RParenLoc));
953}
954
955StmtResult
956Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
957                                 SourceLocation LParenLoc,
958                                 Stmt *First, Expr *Second,
959                                 SourceLocation RParenLoc, Stmt *Body) {
960  if (First) {
961    QualType FirstType;
962    if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) {
963      if (!DS->isSingleDecl())
964        return StmtError(Diag((*DS->decl_begin())->getLocation(),
965                         diag::err_toomany_element_decls));
966
967      Decl *D = DS->getSingleDecl();
968      FirstType = cast<ValueDecl>(D)->getType();
969      // C99 6.8.5p3: The declaration part of a 'for' statement shall only
970      // declare identifiers for objects having storage class 'auto' or
971      // 'register'.
972      VarDecl *VD = cast<VarDecl>(D);
973      if (VD->isLocalVarDecl() && !VD->hasLocalStorage())
974        return StmtError(Diag(VD->getLocation(),
975                              diag::err_non_variable_decl_in_for));
976    } else {
977      Expr *FirstE = cast<Expr>(First);
978      if (!FirstE->isTypeDependent() && !FirstE->isLValue())
979        return StmtError(Diag(First->getLocStart(),
980                   diag::err_selector_element_not_lvalue)
981          << First->getSourceRange());
982
983      FirstType = static_cast<Expr*>(First)->getType();
984    }
985    if (!FirstType->isDependentType() &&
986        !FirstType->isObjCObjectPointerType() &&
987        !FirstType->isBlockPointerType())
988        Diag(ForLoc, diag::err_selector_element_type)
989          << FirstType << First->getSourceRange();
990  }
991  if (Second && !Second->isTypeDependent()) {
992    DefaultFunctionArrayLvalueConversion(Second);
993    QualType SecondType = Second->getType();
994    if (!SecondType->isObjCObjectPointerType())
995      Diag(ForLoc, diag::err_collection_expr_type)
996        << SecondType << Second->getSourceRange();
997    else if (const ObjCObjectPointerType *OPT =
998             SecondType->getAsObjCInterfacePointerType()) {
999      llvm::SmallVector<IdentifierInfo *, 4> KeyIdents;
1000      IdentifierInfo* selIdent =
1001        &Context.Idents.get("countByEnumeratingWithState");
1002      KeyIdents.push_back(selIdent);
1003      selIdent = &Context.Idents.get("objects");
1004      KeyIdents.push_back(selIdent);
1005      selIdent = &Context.Idents.get("count");
1006      KeyIdents.push_back(selIdent);
1007      Selector CSelector = Context.Selectors.getSelector(3, &KeyIdents[0]);
1008      if (ObjCInterfaceDecl *IDecl = OPT->getInterfaceDecl()) {
1009        if (!IDecl->isForwardDecl() &&
1010            !IDecl->lookupInstanceMethod(CSelector)) {
1011          // Must further look into private implementation methods.
1012          if (!LookupPrivateInstanceMethod(CSelector, IDecl))
1013            Diag(ForLoc, diag::warn_collection_expr_type)
1014              << SecondType << CSelector << Second->getSourceRange();
1015        }
1016      }
1017    }
1018  }
1019  return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body,
1020                                                   ForLoc, RParenLoc));
1021}
1022
1023StmtResult
1024Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc,
1025                    IdentifierInfo *LabelII) {
1026  // Look up the record for this label identifier.
1027  LabelStmt *&LabelDecl = getCurFunction()->LabelMap[LabelII];
1028
1029  getCurFunction()->setHasBranchIntoScope();
1030
1031  // If we haven't seen this label yet, create a forward reference.
1032  if (LabelDecl == 0)
1033    LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0);
1034
1035  LabelDecl->setUsed();
1036  return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc));
1037}
1038
1039StmtResult
1040Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
1041                            Expr *E) {
1042  // Convert operand to void*
1043  if (!E->isTypeDependent()) {
1044    QualType ETy = E->getType();
1045    QualType DestTy = Context.getPointerType(Context.VoidTy.withConst());
1046    AssignConvertType ConvTy =
1047      CheckSingleAssignmentConstraints(DestTy, E);
1048    if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing))
1049      return StmtError();
1050  }
1051
1052  getCurFunction()->setHasIndirectGoto();
1053
1054  return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E));
1055}
1056
1057StmtResult
1058Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
1059  Scope *S = CurScope->getContinueParent();
1060  if (!S) {
1061    // C99 6.8.6.2p1: A break shall appear only in or as a loop body.
1062    return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop));
1063  }
1064
1065  return Owned(new (Context) ContinueStmt(ContinueLoc));
1066}
1067
1068StmtResult
1069Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
1070  Scope *S = CurScope->getBreakParent();
1071  if (!S) {
1072    // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
1073    return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch));
1074  }
1075
1076  return Owned(new (Context) BreakStmt(BreakLoc));
1077}
1078
1079/// \brief Determine whether a return statement is a candidate for the named
1080/// return value optimization (C++0x 12.8p34, bullet 1).
1081///
1082/// \param Ctx The context in which the return expression and type occur.
1083///
1084/// \param RetType The return type of the function or block.
1085///
1086/// \param RetExpr The expression being returned from the function or block.
1087///
1088/// \returns The NRVO candidate variable, if the return statement may use the
1089/// NRVO, or NULL if there is no such candidate.
1090static const VarDecl *getNRVOCandidate(ASTContext &Ctx, QualType RetType,
1091                                       Expr *RetExpr) {
1092  QualType ExprType = RetExpr->getType();
1093  // - in a return statement in a function with ...
1094  // ... a class return type ...
1095  if (!RetType->isRecordType())
1096    return 0;
1097  // ... the same cv-unqualified type as the function return type ...
1098  if (!Ctx.hasSameUnqualifiedType(RetType, ExprType))
1099    return 0;
1100  // ... the expression is the name of a non-volatile automatic object ...
1101  // We ignore parentheses here.
1102  // FIXME: Is this compliant? (Everyone else does it)
1103  const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens());
1104  if (!DR)
1105    return 0;
1106  const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl());
1107  if (!VD)
1108    return 0;
1109
1110  if (VD->getKind() == Decl::Var && VD->hasLocalStorage() &&
1111      !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() &&
1112      !VD->getType().isVolatileQualified())
1113    return VD;
1114
1115  return 0;
1116}
1117
1118/// ActOnBlockReturnStmt - Utility routine to figure out block's return type.
1119///
1120StmtResult
1121Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
1122  // If this is the first return we've seen in the block, infer the type of
1123  // the block from it.
1124  BlockScopeInfo *CurBlock = getCurBlock();
1125  if (CurBlock->ReturnType.isNull()) {
1126    if (RetValExp) {
1127      // Don't call UsualUnaryConversions(), since we don't want to do
1128      // integer promotions here.
1129      DefaultFunctionArrayLvalueConversion(RetValExp);
1130      CurBlock->ReturnType = RetValExp->getType();
1131      if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) {
1132        // We have to remove a 'const' added to copied-in variable which was
1133        // part of the implementation spec. and not the actual qualifier for
1134        // the variable.
1135        if (CDRE->isConstQualAdded())
1136           CurBlock->ReturnType.removeConst();
1137      }
1138    } else
1139      CurBlock->ReturnType = Context.VoidTy;
1140  }
1141  QualType FnRetType = CurBlock->ReturnType;
1142
1143  if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) {
1144    Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr)
1145      << getCurFunctionOrMethodDecl()->getDeclName();
1146    return StmtError();
1147  }
1148
1149  // Otherwise, verify that this result type matches the previous one.  We are
1150  // pickier with blocks than for normal functions because we don't have GCC
1151  // compatibility to worry about here.
1152  ReturnStmt *Result = 0;
1153  if (CurBlock->ReturnType->isVoidType()) {
1154    if (RetValExp) {
1155      Diag(ReturnLoc, diag::err_return_block_has_expr);
1156      RetValExp = 0;
1157    }
1158    Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0);
1159  } else if (!RetValExp) {
1160    return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr));
1161  } else {
1162    const VarDecl *NRVOCandidate = 0;
1163
1164    if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) {
1165      // we have a non-void block with an expression, continue checking
1166
1167      // C99 6.8.6.4p3(136): The return statement is not an assignment. The
1168      // overlap restriction of subclause 6.5.16.1 does not apply to the case of
1169      // function return.
1170
1171      // In C++ the return statement is handled via a copy initialization.
1172      // the C version of which boils down to CheckSingleAssignmentConstraints.
1173      NRVOCandidate = getNRVOCandidate(Context, FnRetType, RetValExp);
1174      ExprResult Res = PerformCopyInitialization(
1175                               InitializedEntity::InitializeResult(ReturnLoc,
1176                                                                   FnRetType,
1177                                                            NRVOCandidate != 0),
1178                               SourceLocation(),
1179                               Owned(RetValExp));
1180      if (Res.isInvalid()) {
1181        // FIXME: Cleanup temporaries here, anyway?
1182        return StmtError();
1183      }
1184
1185      if (RetValExp) {
1186        CheckImplicitConversions(RetValExp, ReturnLoc);
1187        RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp);
1188      }
1189
1190      RetValExp = Res.takeAs<Expr>();
1191      if (RetValExp)
1192        CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc);
1193    }
1194
1195    Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate);
1196  }
1197
1198  // If we need to check for the named return value optimization, save the
1199  // return statement in our scope for later processing.
1200  if (getLangOptions().CPlusPlus && FnRetType->isRecordType() &&
1201      !CurContext->isDependentContext())
1202    FunctionScopes.back()->Returns.push_back(Result);
1203
1204  return Owned(Result);
1205}
1206
1207StmtResult
1208Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
1209  if (getCurBlock())
1210    return ActOnBlockReturnStmt(ReturnLoc, RetValExp);
1211
1212  QualType FnRetType;
1213  if (const FunctionDecl *FD = getCurFunctionDecl()) {
1214    FnRetType = FD->getResultType();
1215    if (FD->hasAttr<NoReturnAttr>() ||
1216        FD->getType()->getAs<FunctionType>()->getNoReturnAttr())
1217      Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr)
1218        << getCurFunctionOrMethodDecl()->getDeclName();
1219  } else if (ObjCMethodDecl *MD = getCurMethodDecl())
1220    FnRetType = MD->getResultType();
1221  else // If we don't have a function/method context, bail.
1222    return StmtError();
1223
1224  ReturnStmt *Result = 0;
1225  if (FnRetType->isVoidType()) {
1226    if (RetValExp && !RetValExp->isTypeDependent()) {
1227      // C99 6.8.6.4p1 (ext_ since GCC warns)
1228      unsigned D = diag::ext_return_has_expr;
1229      if (RetValExp->getType()->isVoidType())
1230        D = diag::ext_return_has_void_expr;
1231
1232      // return (some void expression); is legal in C++.
1233      if (D != diag::ext_return_has_void_expr ||
1234          !getLangOptions().CPlusPlus) {
1235        NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
1236        Diag(ReturnLoc, D)
1237          << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl)
1238          << RetValExp->getSourceRange();
1239      }
1240
1241      CheckImplicitConversions(RetValExp, ReturnLoc);
1242      RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp);
1243    }
1244
1245    Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0);
1246  } else if (!RetValExp && !FnRetType->isDependentType()) {
1247    unsigned DiagID = diag::warn_return_missing_expr;  // C90 6.6.6.4p4
1248    // C99 6.8.6.4p1 (ext_ since GCC warns)
1249    if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr;
1250
1251    if (FunctionDecl *FD = getCurFunctionDecl())
1252      Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/;
1253    else
1254      Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/;
1255    Result = new (Context) ReturnStmt(ReturnLoc);
1256  } else {
1257    const VarDecl *NRVOCandidate = 0;
1258    if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) {
1259      // we have a non-void function with an expression, continue checking
1260
1261      // C99 6.8.6.4p3(136): The return statement is not an assignment. The
1262      // overlap restriction of subclause 6.5.16.1 does not apply to the case of
1263      // function return.
1264
1265      // In C++ the return statement is handled via a copy initialization.
1266      // the C version of which boils down to CheckSingleAssignmentConstraints.
1267      NRVOCandidate = getNRVOCandidate(Context, FnRetType, RetValExp);
1268      ExprResult Res = PerformCopyInitialization(
1269                               InitializedEntity::InitializeResult(ReturnLoc,
1270                                                                   FnRetType,
1271                                                            NRVOCandidate != 0),
1272                               SourceLocation(),
1273                               Owned(RetValExp));
1274      if (Res.isInvalid()) {
1275        // FIXME: Cleanup temporaries here, anyway?
1276        return StmtError();
1277      }
1278
1279      RetValExp = Res.takeAs<Expr>();
1280      if (RetValExp)
1281        CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc);
1282    }
1283
1284    if (RetValExp) {
1285      CheckImplicitConversions(RetValExp, ReturnLoc);
1286      RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp);
1287    }
1288    Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate);
1289  }
1290
1291  // If we need to check for the named return value optimization, save the
1292  // return statement in our scope for later processing.
1293  if (getLangOptions().CPlusPlus && FnRetType->isRecordType() &&
1294      !CurContext->isDependentContext())
1295    FunctionScopes.back()->Returns.push_back(Result);
1296
1297  return Owned(Result);
1298}
1299
1300/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently
1301/// ignore "noop" casts in places where an lvalue is required by an inline asm.
1302/// We emulate this behavior when -fheinous-gnu-extensions is specified, but
1303/// provide a strong guidance to not use it.
1304///
1305/// This method checks to see if the argument is an acceptable l-value and
1306/// returns false if it is a case we can handle.
1307static bool CheckAsmLValue(const Expr *E, Sema &S) {
1308  // Type dependent expressions will be checked during instantiation.
1309  if (E->isTypeDependent())
1310    return false;
1311
1312  if (E->isLValue())
1313    return false;  // Cool, this is an lvalue.
1314
1315  // Okay, this is not an lvalue, but perhaps it is the result of a cast that we
1316  // are supposed to allow.
1317  const Expr *E2 = E->IgnoreParenNoopCasts(S.Context);
1318  if (E != E2 && E2->isLValue()) {
1319    if (!S.getLangOptions().HeinousExtensions)
1320      S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue)
1321        << E->getSourceRange();
1322    else
1323      S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue)
1324        << E->getSourceRange();
1325    // Accept, even if we emitted an error diagnostic.
1326    return false;
1327  }
1328
1329  // None of the above, just randomly invalid non-lvalue.
1330  return true;
1331}
1332
1333
1334StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc,
1335                                          bool IsSimple,
1336                                          bool IsVolatile,
1337                                          unsigned NumOutputs,
1338                                          unsigned NumInputs,
1339                                          IdentifierInfo **Names,
1340                                          MultiExprArg constraints,
1341                                          MultiExprArg exprs,
1342                                          Expr *asmString,
1343                                          MultiExprArg clobbers,
1344                                          SourceLocation RParenLoc,
1345                                          bool MSAsm) {
1346  unsigned NumClobbers = clobbers.size();
1347  StringLiteral **Constraints =
1348    reinterpret_cast<StringLiteral**>(constraints.get());
1349  Expr **Exprs = exprs.get();
1350  StringLiteral *AsmString = cast<StringLiteral>(asmString);
1351  StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get());
1352
1353  llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
1354
1355  // The parser verifies that there is a string literal here.
1356  if (AsmString->isWide())
1357    return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character)
1358      << AsmString->getSourceRange());
1359
1360  for (unsigned i = 0; i != NumOutputs; i++) {
1361    StringLiteral *Literal = Constraints[i];
1362    if (Literal->isWide())
1363      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
1364        << Literal->getSourceRange());
1365
1366    llvm::StringRef OutputName;
1367    if (Names[i])
1368      OutputName = Names[i]->getName();
1369
1370    TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName);
1371    if (!Context.Target.validateOutputConstraint(Info))
1372      return StmtError(Diag(Literal->getLocStart(),
1373                            diag::err_asm_invalid_output_constraint)
1374                       << Info.getConstraintStr());
1375
1376    // Check that the output exprs are valid lvalues.
1377    Expr *OutputExpr = Exprs[i];
1378    if (CheckAsmLValue(OutputExpr, *this)) {
1379      return StmtError(Diag(OutputExpr->getLocStart(),
1380                  diag::err_asm_invalid_lvalue_in_output)
1381        << OutputExpr->getSourceRange());
1382    }
1383
1384    OutputConstraintInfos.push_back(Info);
1385  }
1386
1387  llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
1388
1389  for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
1390    StringLiteral *Literal = Constraints[i];
1391    if (Literal->isWide())
1392      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
1393        << Literal->getSourceRange());
1394
1395    llvm::StringRef InputName;
1396    if (Names[i])
1397      InputName = Names[i]->getName();
1398
1399    TargetInfo::ConstraintInfo Info(Literal->getString(), InputName);
1400    if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(),
1401                                                NumOutputs, Info)) {
1402      return StmtError(Diag(Literal->getLocStart(),
1403                            diag::err_asm_invalid_input_constraint)
1404                       << Info.getConstraintStr());
1405    }
1406
1407    Expr *InputExpr = Exprs[i];
1408
1409    // Only allow void types for memory constraints.
1410    if (Info.allowsMemory() && !Info.allowsRegister()) {
1411      if (CheckAsmLValue(InputExpr, *this))
1412        return StmtError(Diag(InputExpr->getLocStart(),
1413                              diag::err_asm_invalid_lvalue_in_input)
1414                         << Info.getConstraintStr()
1415                         << InputExpr->getSourceRange());
1416    }
1417
1418    if (Info.allowsRegister()) {
1419      if (InputExpr->getType()->isVoidType()) {
1420        return StmtError(Diag(InputExpr->getLocStart(),
1421                              diag::err_asm_invalid_type_in_input)
1422          << InputExpr->getType() << Info.getConstraintStr()
1423          << InputExpr->getSourceRange());
1424      }
1425    }
1426
1427    DefaultFunctionArrayLvalueConversion(Exprs[i]);
1428
1429    InputConstraintInfos.push_back(Info);
1430  }
1431
1432  // Check that the clobbers are valid.
1433  for (unsigned i = 0; i != NumClobbers; i++) {
1434    StringLiteral *Literal = Clobbers[i];
1435    if (Literal->isWide())
1436      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
1437        << Literal->getSourceRange());
1438
1439    llvm::StringRef Clobber = Literal->getString();
1440
1441    if (!Context.Target.isValidGCCRegisterName(Clobber))
1442      return StmtError(Diag(Literal->getLocStart(),
1443                  diag::err_asm_unknown_register_name) << Clobber);
1444  }
1445
1446  AsmStmt *NS =
1447    new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm,
1448                          NumOutputs, NumInputs, Names, Constraints, Exprs,
1449                          AsmString, NumClobbers, Clobbers, RParenLoc);
1450  // Validate the asm string, ensuring it makes sense given the operands we
1451  // have.
1452  llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces;
1453  unsigned DiagOffs;
1454  if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) {
1455    Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID)
1456           << AsmString->getSourceRange();
1457    return StmtError();
1458  }
1459
1460  // Validate tied input operands for type mismatches.
1461  for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
1462    TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
1463
1464    // If this is a tied constraint, verify that the output and input have
1465    // either exactly the same type, or that they are int/ptr operands with the
1466    // same size (int/long, int*/long, are ok etc).
1467    if (!Info.hasTiedOperand()) continue;
1468
1469    unsigned TiedTo = Info.getTiedOperand();
1470    Expr *OutputExpr = Exprs[TiedTo];
1471    Expr *InputExpr = Exprs[i+NumOutputs];
1472    QualType InTy = InputExpr->getType();
1473    QualType OutTy = OutputExpr->getType();
1474    if (Context.hasSameType(InTy, OutTy))
1475      continue;  // All types can be tied to themselves.
1476
1477    // Decide if the input and output are in the same domain (integer/ptr or
1478    // floating point.
1479    enum AsmDomain {
1480      AD_Int, AD_FP, AD_Other
1481    } InputDomain, OutputDomain;
1482
1483    if (InTy->isIntegerType() || InTy->isPointerType())
1484      InputDomain = AD_Int;
1485    else if (InTy->isRealFloatingType())
1486      InputDomain = AD_FP;
1487    else
1488      InputDomain = AD_Other;
1489
1490    if (OutTy->isIntegerType() || OutTy->isPointerType())
1491      OutputDomain = AD_Int;
1492    else if (OutTy->isRealFloatingType())
1493      OutputDomain = AD_FP;
1494    else
1495      OutputDomain = AD_Other;
1496
1497    // They are ok if they are the same size and in the same domain.  This
1498    // allows tying things like:
1499    //   void* to int*
1500    //   void* to int            if they are the same size.
1501    //   double to long double   if they are the same size.
1502    //
1503    uint64_t OutSize = Context.getTypeSize(OutTy);
1504    uint64_t InSize = Context.getTypeSize(InTy);
1505    if (OutSize == InSize && InputDomain == OutputDomain &&
1506        InputDomain != AD_Other)
1507      continue;
1508
1509    // If the smaller input/output operand is not mentioned in the asm string,
1510    // then we can promote it and the asm string won't notice.  Check this
1511    // case now.
1512    bool SmallerValueMentioned = false;
1513    for (unsigned p = 0, e = Pieces.size(); p != e; ++p) {
1514      AsmStmt::AsmStringPiece &Piece = Pieces[p];
1515      if (!Piece.isOperand()) continue;
1516
1517      // If this is a reference to the input and if the input was the smaller
1518      // one, then we have to reject this asm.
1519      if (Piece.getOperandNo() == i+NumOutputs) {
1520        if (InSize < OutSize) {
1521          SmallerValueMentioned = true;
1522          break;
1523        }
1524      }
1525
1526      // If this is a reference to the input and if the input was the smaller
1527      // one, then we have to reject this asm.
1528      if (Piece.getOperandNo() == TiedTo) {
1529        if (InSize > OutSize) {
1530          SmallerValueMentioned = true;
1531          break;
1532        }
1533      }
1534    }
1535
1536    // If the smaller value wasn't mentioned in the asm string, and if the
1537    // output was a register, just extend the shorter one to the size of the
1538    // larger one.
1539    if (!SmallerValueMentioned && InputDomain != AD_Other &&
1540        OutputConstraintInfos[TiedTo].allowsRegister())
1541      continue;
1542
1543    Diag(InputExpr->getLocStart(),
1544         diag::err_asm_tying_incompatible_types)
1545      << InTy << OutTy << OutputExpr->getSourceRange()
1546      << InputExpr->getSourceRange();
1547    return StmtError();
1548  }
1549
1550  return Owned(NS);
1551}
1552
1553StmtResult
1554Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
1555                           SourceLocation RParen, Decl *Parm,
1556                           Stmt *Body) {
1557  VarDecl *Var = cast_or_null<VarDecl>(Parm);
1558  if (Var && Var->isInvalidDecl())
1559    return StmtError();
1560
1561  return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body));
1562}
1563
1564StmtResult
1565Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) {
1566  return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body));
1567}
1568
1569StmtResult
1570Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
1571                         MultiStmtArg CatchStmts, Stmt *Finally) {
1572  getCurFunction()->setHasBranchProtectedScope();
1573  unsigned NumCatchStmts = CatchStmts.size();
1574  return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try,
1575                                     CatchStmts.release(),
1576                                     NumCatchStmts,
1577                                     Finally));
1578}
1579
1580StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc,
1581                                                  Expr *Throw) {
1582  if (Throw) {
1583    QualType ThrowType = Throw->getType();
1584    // Make sure the expression type is an ObjC pointer or "void *".
1585    if (!ThrowType->isDependentType() &&
1586        !ThrowType->isObjCObjectPointerType()) {
1587      const PointerType *PT = ThrowType->getAs<PointerType>();
1588      if (!PT || !PT->getPointeeType()->isVoidType())
1589        return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object)
1590                         << Throw->getType() << Throw->getSourceRange());
1591    }
1592  }
1593
1594  return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw));
1595}
1596
1597StmtResult
1598Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw,
1599                           Scope *CurScope) {
1600  if (!Throw) {
1601    // @throw without an expression designates a rethrow (which much occur
1602    // in the context of an @catch clause).
1603    Scope *AtCatchParent = CurScope;
1604    while (AtCatchParent && !AtCatchParent->isAtCatchScope())
1605      AtCatchParent = AtCatchParent->getParent();
1606    if (!AtCatchParent)
1607      return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch));
1608  }
1609
1610  return BuildObjCAtThrowStmt(AtLoc, Throw);
1611}
1612
1613StmtResult
1614Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr,
1615                                  Stmt *SyncBody) {
1616  getCurFunction()->setHasBranchProtectedScope();
1617
1618  // Make sure the expression type is an ObjC pointer or "void *".
1619  if (!SyncExpr->getType()->isDependentType() &&
1620      !SyncExpr->getType()->isObjCObjectPointerType()) {
1621    const PointerType *PT = SyncExpr->getType()->getAs<PointerType>();
1622    if (!PT || !PT->getPointeeType()->isVoidType())
1623      return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object)
1624                       << SyncExpr->getType() << SyncExpr->getSourceRange());
1625  }
1626
1627  return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody));
1628}
1629
1630/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
1631/// and creates a proper catch handler from them.
1632StmtResult
1633Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
1634                         Stmt *HandlerBlock) {
1635  // There's nothing to test that ActOnExceptionDecl didn't already test.
1636  return Owned(new (Context) CXXCatchStmt(CatchLoc,
1637                                          cast_or_null<VarDecl>(ExDecl),
1638                                          HandlerBlock));
1639}
1640
1641namespace {
1642
1643class TypeWithHandler {
1644  QualType t;
1645  CXXCatchStmt *stmt;
1646public:
1647  TypeWithHandler(const QualType &type, CXXCatchStmt *statement)
1648  : t(type), stmt(statement) {}
1649
1650  // An arbitrary order is fine as long as it places identical
1651  // types next to each other.
1652  bool operator<(const TypeWithHandler &y) const {
1653    if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr())
1654      return true;
1655    if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr())
1656      return false;
1657    else
1658      return getTypeSpecStartLoc() < y.getTypeSpecStartLoc();
1659  }
1660
1661  bool operator==(const TypeWithHandler& other) const {
1662    return t == other.t;
1663  }
1664
1665  CXXCatchStmt *getCatchStmt() const { return stmt; }
1666  SourceLocation getTypeSpecStartLoc() const {
1667    return stmt->getExceptionDecl()->getTypeSpecStartLoc();
1668  }
1669};
1670
1671}
1672
1673/// ActOnCXXTryBlock - Takes a try compound-statement and a number of
1674/// handlers and creates a try statement from them.
1675StmtResult
1676Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
1677                       MultiStmtArg RawHandlers) {
1678  unsigned NumHandlers = RawHandlers.size();
1679  assert(NumHandlers > 0 &&
1680         "The parser shouldn't call this if there are no handlers.");
1681  Stmt **Handlers = RawHandlers.get();
1682
1683  llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers;
1684
1685  for (unsigned i = 0; i < NumHandlers; ++i) {
1686    CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]);
1687    if (!Handler->getExceptionDecl()) {
1688      if (i < NumHandlers - 1)
1689        return StmtError(Diag(Handler->getLocStart(),
1690                              diag::err_early_catch_all));
1691
1692      continue;
1693    }
1694
1695    const QualType CaughtType = Handler->getCaughtType();
1696    const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType);
1697    TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler));
1698  }
1699
1700  // Detect handlers for the same type as an earlier one.
1701  if (NumHandlers > 1) {
1702    llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end());
1703
1704    TypeWithHandler prev = TypesWithHandlers[0];
1705    for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) {
1706      TypeWithHandler curr = TypesWithHandlers[i];
1707
1708      if (curr == prev) {
1709        Diag(curr.getTypeSpecStartLoc(),
1710             diag::warn_exception_caught_by_earlier_handler)
1711          << curr.getCatchStmt()->getCaughtType().getAsString();
1712        Diag(prev.getTypeSpecStartLoc(),
1713             diag::note_previous_exception_handler)
1714          << prev.getCatchStmt()->getCaughtType().getAsString();
1715      }
1716
1717      prev = curr;
1718    }
1719  }
1720
1721  getCurFunction()->setHasBranchProtectedScope();
1722
1723  // FIXME: We should detect handlers that cannot catch anything because an
1724  // earlier handler catches a superclass. Need to find a method that is not
1725  // quadratic for this.
1726  // Neither of these are explicitly forbidden, but every compiler detects them
1727  // and warns.
1728
1729  return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock,
1730                                  Handlers, NumHandlers));
1731}
1732