SemaStmt.cpp revision d3d5301c44138b92bf01286183f5bf310cdd37cf 
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 "clang/AST/APValue.h"
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/DeclObjC.h"
18#include "clang/AST/ExprCXX.h"
19#include "clang/AST/ExprObjC.h"
20#include "clang/AST/StmtObjC.h"
21#include "clang/AST/StmtCXX.h"
22#include "clang/Lex/Preprocessor.h"
23#include "clang/Basic/TargetInfo.h"
24#include "llvm/ADT/STLExtras.h"
25#include "llvm/ADT/SmallVector.h"
26using namespace clang;
27
28Sema::OwningStmtResult Sema::ActOnExprStmt(FullExprArg expr) {
29  Expr *E = expr->takeAs<Expr>();
30  assert(E && "ActOnExprStmt(): missing expression");
31  if (E->getType()->isObjCInterfaceType()) {
32    if (LangOpts.ObjCNonFragileABI)
33      Diag(E->getLocEnd(), diag::err_indirection_requires_nonfragile_object)
34             << E->getType();
35    else
36      Diag(E->getLocEnd(), diag::err_direct_interface_unsupported)
37             << E->getType();
38    return StmtError();
39  }
40  // C99 6.8.3p2: The expression in an expression statement is evaluated as a
41  // void expression for its side effects.  Conversion to void allows any
42  // operand, even incomplete types.
43
44  // Same thing in for stmt first clause (when expr) and third clause.
45  return Owned(static_cast<Stmt*>(E));
46}
47
48
49Sema::OwningStmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc) {
50  return Owned(new (Context) NullStmt(SemiLoc));
51}
52
53Sema::OwningStmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg,
54                                           SourceLocation StartLoc,
55                                           SourceLocation EndLoc) {
56  DeclGroupRef DG = dg.getAsVal<DeclGroupRef>();
57
58  // If we have an invalid decl, just return an error.
59  if (DG.isNull()) return StmtError();
60
61  return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc));
62}
63
64void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
65  DeclGroupRef DG = dg.getAsVal<DeclGroupRef>();
66
67  // If we have an invalid decl, just return.
68  if (DG.isNull() || !DG.isSingleDecl()) return;
69  // suppress any potential 'unused variable' warning.
70  DG.getSingleDecl()->setUsed();
71}
72
73void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
74  const Expr *E = dyn_cast_or_null<Expr>(S);
75  if (!E)
76    return;
77
78  // Ignore expressions that have void type.
79  if (E->getType()->isVoidType())
80    return;
81
82  SourceLocation Loc;
83  SourceRange R1, R2;
84  if (!E->isUnusedResultAWarning(Loc, R1, R2, Context))
85    return;
86
87  // Okay, we have an unused result.  Depending on what the base expression is,
88  // we might want to make a more specific diagnostic.  Check for one of these
89  // cases now.
90  unsigned DiagID = diag::warn_unused_expr;
91  E = E->IgnoreParens();
92  if (isa<ObjCImplicitSetterGetterRefExpr>(E))
93    DiagID = diag::warn_unused_property_expr;
94
95  if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
96    // If the callee has attribute pure, const, or warn_unused_result, warn with
97    // a more specific message to make it clear what is happening.
98    if (const FunctionDecl *FD = CE->getDirectCallee()) {
99      if (FD->getAttr<WarnUnusedResultAttr>()) {
100        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result";
101        return;
102      }
103      if (FD->getAttr<PureAttr>()) {
104        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure";
105        return;
106      }
107      if (FD->getAttr<ConstAttr>()) {
108        Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const";
109        return;
110      }
111    }
112  }
113
114  Diag(Loc, DiagID) << R1 << R2;
115}
116
117Action::OwningStmtResult
118Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
119                        MultiStmtArg elts, bool isStmtExpr) {
120  unsigned NumElts = elts.size();
121  Stmt **Elts = reinterpret_cast<Stmt**>(elts.release());
122  // If we're in C89 mode, check that we don't have any decls after stmts.  If
123  // so, emit an extension diagnostic.
124  if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) {
125    // Note that __extension__ can be around a decl.
126    unsigned i = 0;
127    // Skip over all declarations.
128    for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i)
129      /*empty*/;
130
131    // We found the end of the list or a statement.  Scan for another declstmt.
132    for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i)
133      /*empty*/;
134
135    if (i != NumElts) {
136      Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin();
137      Diag(D->getLocation(), diag::ext_mixed_decls_code);
138    }
139  }
140  // Warn about unused expressions in statements.
141  for (unsigned i = 0; i != NumElts; ++i) {
142    // Ignore statements that are last in a statement expression.
143    if (isStmtExpr && i == NumElts - 1)
144      continue;
145
146    DiagnoseUnusedExprResult(Elts[i]);
147  }
148
149  return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R));
150}
151
152Action::OwningStmtResult
153Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprArg lhsval,
154                    SourceLocation DotDotDotLoc, ExprArg rhsval,
155                    SourceLocation ColonLoc) {
156  assert((lhsval.get() != 0) && "missing expression in case statement");
157
158  // C99 6.8.4.2p3: The expression shall be an integer constant.
159  // However, GCC allows any evaluatable integer expression.
160  Expr *LHSVal = static_cast<Expr*>(lhsval.get());
161  if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() &&
162      VerifyIntegerConstantExpression(LHSVal))
163    return StmtError();
164
165  // GCC extension: The expression shall be an integer constant.
166
167  Expr *RHSVal = static_cast<Expr*>(rhsval.get());
168  if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() &&
169      VerifyIntegerConstantExpression(RHSVal)) {
170    RHSVal = 0;  // Recover by just forgetting about it.
171    rhsval = 0;
172  }
173
174  if (getSwitchStack().empty()) {
175    Diag(CaseLoc, diag::err_case_not_in_switch);
176    return StmtError();
177  }
178
179  // Only now release the smart pointers.
180  lhsval.release();
181  rhsval.release();
182  CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc,
183                                        ColonLoc);
184  getSwitchStack().back()->addSwitchCase(CS);
185  return Owned(CS);
186}
187
188/// ActOnCaseStmtBody - This installs a statement as the body of a case.
189void Sema::ActOnCaseStmtBody(StmtTy *caseStmt, StmtArg subStmt) {
190  CaseStmt *CS = static_cast<CaseStmt*>(caseStmt);
191  Stmt *SubStmt = subStmt.takeAs<Stmt>();
192  CS->setSubStmt(SubStmt);
193}
194
195Action::OwningStmtResult
196Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
197                       StmtArg subStmt, Scope *CurScope) {
198  Stmt *SubStmt = subStmt.takeAs<Stmt>();
199
200  if (getSwitchStack().empty()) {
201    Diag(DefaultLoc, diag::err_default_not_in_switch);
202    return Owned(SubStmt);
203  }
204
205  DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
206  getSwitchStack().back()->addSwitchCase(DS);
207  return Owned(DS);
208}
209
210Action::OwningStmtResult
211Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II,
212                     SourceLocation ColonLoc, StmtArg subStmt) {
213  Stmt *SubStmt = subStmt.takeAs<Stmt>();
214  // Look up the record for this label identifier.
215  LabelStmt *&LabelDecl = getLabelMap()[II];
216
217  // If not forward referenced or defined already, just create a new LabelStmt.
218  if (LabelDecl == 0)
219    return Owned(LabelDecl = new (Context) LabelStmt(IdentLoc, II, SubStmt));
220
221  assert(LabelDecl->getID() == II && "Label mismatch!");
222
223  // Otherwise, this label was either forward reference or multiply defined.  If
224  // multiply defined, reject it now.
225  if (LabelDecl->getSubStmt()) {
226    Diag(IdentLoc, diag::err_redefinition_of_label) << LabelDecl->getID();
227    Diag(LabelDecl->getIdentLoc(), diag::note_previous_definition);
228    return Owned(SubStmt);
229  }
230
231  // Otherwise, this label was forward declared, and we just found its real
232  // definition.  Fill in the forward definition and return it.
233  LabelDecl->setIdentLoc(IdentLoc);
234  LabelDecl->setSubStmt(SubStmt);
235  return Owned(LabelDecl);
236}
237
238Action::OwningStmtResult
239Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal,
240                  StmtArg ThenVal, SourceLocation ElseLoc,
241                  StmtArg ElseVal) {
242  OwningExprResult CondResult(CondVal.release());
243
244  Expr *condExpr = CondResult.takeAs<Expr>();
245  assert(condExpr && "ActOnIfStmt(): missing expression");
246
247  VarDecl *ConditionVar = 0;
248  if (CXXConditionDeclExpr *Cond = dyn_cast<CXXConditionDeclExpr>(condExpr)) {
249    ConditionVar = Cond->getVarDecl();
250    condExpr = DeclRefExpr::Create(Context, 0, SourceRange(), ConditionVar,
251                                   ConditionVar->getLocation(),
252                                 ConditionVar->getType().getNonReferenceType());
253    // FIXME: Leaks the old condExpr
254  }
255
256  if (CheckBooleanCondition(condExpr, IfLoc)) {
257    CondResult = condExpr;
258    return StmtError();
259  }
260
261  Stmt *thenStmt = ThenVal.takeAs<Stmt>();
262  DiagnoseUnusedExprResult(thenStmt);
263
264  // Warn if the if block has a null body without an else value.
265  // this helps prevent bugs due to typos, such as
266  // if (condition);
267  //   do_stuff();
268  if (!ElseVal.get()) {
269    if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt))
270      Diag(stmt->getSemiLoc(), diag::warn_empty_if_body);
271  }
272
273  Stmt *elseStmt = ElseVal.takeAs<Stmt>();
274  DiagnoseUnusedExprResult(elseStmt);
275
276  CondResult.release();
277  return Owned(new (Context) IfStmt(IfLoc, ConditionVar, condExpr, thenStmt,
278                                    ElseLoc, elseStmt));
279}
280
281Action::OwningStmtResult
282Sema::ActOnStartOfSwitchStmt(ExprArg cond) {
283  Expr *condExpr = cond.takeAs<Expr>();
284  VarDecl *ConditionVar = 0;
285  if (CXXConditionDeclExpr *Cond = dyn_cast<CXXConditionDeclExpr>(condExpr)) {
286    ConditionVar = Cond->getVarDecl();
287    condExpr = DeclRefExpr::Create(Context, 0, SourceRange(), ConditionVar,
288                                   ConditionVar->getLocation(),
289                                 ConditionVar->getType().getNonReferenceType());
290    // FIXME: Leaks the old condExpr
291  }
292
293  SwitchStmt *SS = new (Context) SwitchStmt(ConditionVar, condExpr);
294  getSwitchStack().push_back(SS);
295  return Owned(SS);
296}
297
298/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have
299/// the specified width and sign.  If an overflow occurs, detect it and emit
300/// the specified diagnostic.
301void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val,
302                                              unsigned NewWidth, bool NewSign,
303                                              SourceLocation Loc,
304                                              unsigned DiagID) {
305  // Perform a conversion to the promoted condition type if needed.
306  if (NewWidth > Val.getBitWidth()) {
307    // If this is an extension, just do it.
308    llvm::APSInt OldVal(Val);
309    Val.extend(NewWidth);
310
311    // If the input was signed and negative and the output is unsigned,
312    // warn.
313    if (!NewSign && OldVal.isSigned() && OldVal.isNegative())
314      Diag(Loc, DiagID) << OldVal.toString(10) << Val.toString(10);
315
316    Val.setIsSigned(NewSign);
317  } else if (NewWidth < Val.getBitWidth()) {
318    // If this is a truncation, check for overflow.
319    llvm::APSInt ConvVal(Val);
320    ConvVal.trunc(NewWidth);
321    ConvVal.setIsSigned(NewSign);
322    ConvVal.extend(Val.getBitWidth());
323    ConvVal.setIsSigned(Val.isSigned());
324    if (ConvVal != Val)
325      Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10);
326
327    // Regardless of whether a diagnostic was emitted, really do the
328    // truncation.
329    Val.trunc(NewWidth);
330    Val.setIsSigned(NewSign);
331  } else if (NewSign != Val.isSigned()) {
332    // Convert the sign to match the sign of the condition.  This can cause
333    // overflow as well: unsigned(INTMIN)
334    llvm::APSInt OldVal(Val);
335    Val.setIsSigned(NewSign);
336
337    if (Val.isNegative())  // Sign bit changes meaning.
338      Diag(Loc, DiagID) << OldVal.toString(10) << Val.toString(10);
339  }
340}
341
342namespace {
343  struct CaseCompareFunctor {
344    bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
345                    const llvm::APSInt &RHS) {
346      return LHS.first < RHS;
347    }
348    bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
349                    const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
350      return LHS.first < RHS.first;
351    }
352    bool operator()(const llvm::APSInt &LHS,
353                    const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
354      return LHS < RHS.first;
355    }
356  };
357}
358
359/// CmpCaseVals - Comparison predicate for sorting case values.
360///
361static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
362                        const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
363  if (lhs.first < rhs.first)
364    return true;
365
366  if (lhs.first == rhs.first &&
367      lhs.second->getCaseLoc().getRawEncoding()
368       < rhs.second->getCaseLoc().getRawEncoding())
369    return true;
370  return false;
371}
372
373/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
374/// potentially integral-promoted expression @p expr.
375static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) {
376  const ImplicitCastExpr *ImplicitCast =
377      dyn_cast_or_null<ImplicitCastExpr>(expr);
378  if (ImplicitCast != NULL) {
379    const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr();
380    QualType TypeBeforePromotion = ExprBeforePromotion->getType();
381    if (TypeBeforePromotion->isIntegralType()) {
382      return TypeBeforePromotion;
383    }
384  }
385  return expr->getType();
386}
387
388Action::OwningStmtResult
389Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, StmtArg Switch,
390                            StmtArg Body) {
391  Stmt *BodyStmt = Body.takeAs<Stmt>();
392
393  SwitchStmt *SS = getSwitchStack().back();
394  assert(SS == (SwitchStmt*)Switch.get() && "switch stack missing push/pop!");
395
396  SS->setBody(BodyStmt, SwitchLoc);
397  getSwitchStack().pop_back();
398
399  Expr *CondExpr = SS->getCond();
400  QualType CondTypeBeforePromotion =
401      GetTypeBeforeIntegralPromotion(CondExpr);
402  QualType CondType = CondExpr->getType();
403
404  if (getLangOptions().CPlusPlus) {
405    // C++ 6.4.2.p2:
406    // The condition shall be of integral type, enumeration type, or of a class
407    // type for which a single conversion function to integral or enumeration
408    // type exists (12.3). If the condition is of class type, the condition is
409    // converted by calling that conversion function, and the result of the
410    // conversion is used in place of the original condition for the remainder
411    // of this section. Integral promotions are performed.
412    if (!CondExpr->isTypeDependent()) {
413      // Make sure that the condition expression has a complete type,
414      // otherwise we'll never find any conversions.
415      if (RequireCompleteType(SwitchLoc, CondType,
416                              PDiag(diag::err_switch_incomplete_class_type)
417                                << CondExpr->getSourceRange()))
418        return StmtError();
419
420      llvm::SmallVector<CXXConversionDecl *, 4> ViableConversions;
421      llvm::SmallVector<CXXConversionDecl *, 4> ExplicitConversions;
422      if (const RecordType *RecordTy = CondType->getAs<RecordType>()) {
423        const UnresolvedSet *Conversions
424          = cast<CXXRecordDecl>(RecordTy->getDecl())
425                           ->getVisibleConversionFunctions();
426        for (UnresolvedSet::iterator I = Conversions->begin(),
427               E = Conversions->end(); I != E; ++I) {
428          if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(*I))
429            if (Conversion->getConversionType().getNonReferenceType()
430                  ->isIntegralType()) {
431              if (Conversion->isExplicit())
432                ExplicitConversions.push_back(Conversion);
433              else
434              ViableConversions.push_back(Conversion);
435            }
436        }
437
438        switch (ViableConversions.size()) {
439        case 0:
440          if (ExplicitConversions.size() == 1) {
441            // The user probably meant to invoke the given explicit
442            // conversion; use it.
443            QualType ConvTy
444              = ExplicitConversions[0]->getConversionType()
445                            .getNonReferenceType();
446            std::string TypeStr;
447            ConvTy.getAsStringInternal(TypeStr, Context.PrintingPolicy);
448
449
450            Diag(SwitchLoc, diag::err_switch_explicit_conversion)
451              << CondType << ConvTy << CondExpr->getSourceRange()
452              << CodeModificationHint::CreateInsertion(CondExpr->getLocStart(),
453                                             "static_cast<" + TypeStr + ">(")
454              << CodeModificationHint::CreateInsertion(
455                                PP.getLocForEndOfToken(CondExpr->getLocEnd()),
456                                   ")");
457            Diag(ExplicitConversions[0]->getLocation(),
458                 diag::note_switch_conversion)
459              << ConvTy->isEnumeralType() << ConvTy;
460
461            // If we aren't in a SFINAE context, build a call to the
462            // explicit conversion function.
463            if (!isSFINAEContext())
464              CondExpr = BuildCXXMemberCallExpr(CondExpr,
465                                                ExplicitConversions[0]);
466          }
467
468          // We'll complain below about a non-integral condition type.
469          break;
470
471        case 1:
472          // Apply this conversion.
473          CondExpr = BuildCXXMemberCallExpr(CondExpr, ViableConversions[0]);
474          break;
475
476        default:
477          Diag(SwitchLoc, diag::err_switch_multiple_conversions)
478            << CondType << CondExpr->getSourceRange();
479          for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
480            QualType ConvTy
481              = ViableConversions[I]->getConversionType()
482                            .getNonReferenceType();
483            Diag(ViableConversions[I]->getLocation(),
484                 diag::note_switch_conversion)
485              << ConvTy->isEnumeralType() << ConvTy;
486          }
487          return StmtError();
488        }
489      }
490      CondType = CondExpr->getType();
491
492      if (CondType->isIntegralType() || CondType->isEnumeralType()) {
493        // Integral promotions are performed.
494        UsualUnaryConversions(CondExpr);
495      }
496    }
497  } else {
498    // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
499    UsualUnaryConversions(CondExpr);
500  }
501  CondType = CondExpr->getType();
502  SS->setCond(CondExpr);
503
504  // C++ 6.4.2.p2:
505  // Integral promotions are performed (on the switch condition).
506  //
507  // A case value unrepresentable by the original switch condition
508  // type (before the promotion) doesn't make sense, even when it can
509  // be represented by the promoted type.  Therefore we need to find
510  // the pre-promotion type of the switch condition.
511  if (!CondExpr->isTypeDependent()) {
512    if (!CondType->isIntegerType()) { // C99 6.8.4.2p1
513      Diag(SwitchLoc, diag::err_typecheck_statement_requires_integer)
514          << CondType << CondExpr->getSourceRange();
515      return StmtError();
516    }
517
518    if (CondTypeBeforePromotion->isBooleanType()) {
519      // switch(bool_expr) {...} is often a programmer error, e.g.
520      //   switch(n && mask) { ... }  // Doh - should be "n & mask".
521      // One can always use an if statement instead of switch(bool_expr).
522      Diag(SwitchLoc, diag::warn_bool_switch_condition)
523          << CondExpr->getSourceRange();
524    }
525  }
526
527  // Get the bitwidth of the switched-on value before promotions.  We must
528  // convert the integer case values to this width before comparison.
529  bool HasDependentValue
530    = CondExpr->isTypeDependent() || CondExpr->isValueDependent();
531  unsigned CondWidth
532    = HasDependentValue? 0
533      : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion));
534  bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType();
535
536  // Accumulate all of the case values in a vector so that we can sort them
537  // and detect duplicates.  This vector contains the APInt for the case after
538  // it has been converted to the condition type.
539  typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
540  CaseValsTy CaseVals;
541
542  // Keep track of any GNU case ranges we see.  The APSInt is the low value.
543  std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRanges;
544
545  DefaultStmt *TheDefaultStmt = 0;
546
547  bool CaseListIsErroneous = false;
548
549  for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
550       SC = SC->getNextSwitchCase()) {
551
552    if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) {
553      if (TheDefaultStmt) {
554        Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
555        Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev);
556
557        // FIXME: Remove the default statement from the switch block so that
558        // we'll return a valid AST.  This requires recursing down the AST and
559        // finding it, not something we are set up to do right now.  For now,
560        // just lop the entire switch stmt out of the AST.
561        CaseListIsErroneous = true;
562      }
563      TheDefaultStmt = DS;
564
565    } else {
566      CaseStmt *CS = cast<CaseStmt>(SC);
567
568      // We already verified that the expression has a i-c-e value (C99
569      // 6.8.4.2p3) - get that value now.
570      Expr *Lo = CS->getLHS();
571
572      if (Lo->isTypeDependent() || Lo->isValueDependent()) {
573        HasDependentValue = true;
574        break;
575      }
576
577      llvm::APSInt LoVal = Lo->EvaluateAsInt(Context);
578
579      // Convert the value to the same width/sign as the condition.
580      ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned,
581                                         CS->getLHS()->getLocStart(),
582                                         diag::warn_case_value_overflow);
583
584      // If the LHS is not the same type as the condition, insert an implicit
585      // cast.
586      ImpCastExprToType(Lo, CondType, CastExpr::CK_IntegralCast);
587      CS->setLHS(Lo);
588
589      // If this is a case range, remember it in CaseRanges, otherwise CaseVals.
590      if (CS->getRHS()) {
591        if (CS->getRHS()->isTypeDependent() ||
592            CS->getRHS()->isValueDependent()) {
593          HasDependentValue = true;
594          break;
595        }
596        CaseRanges.push_back(std::make_pair(LoVal, CS));
597      } else
598        CaseVals.push_back(std::make_pair(LoVal, CS));
599    }
600  }
601
602  if (!HasDependentValue) {
603    // Sort all the scalar case values so we can easily detect duplicates.
604    std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals);
605
606    if (!CaseVals.empty()) {
607      for (unsigned i = 0, e = CaseVals.size()-1; i != e; ++i) {
608        if (CaseVals[i].first == CaseVals[i+1].first) {
609          // If we have a duplicate, report it.
610          Diag(CaseVals[i+1].second->getLHS()->getLocStart(),
611               diag::err_duplicate_case) << CaseVals[i].first.toString(10);
612          Diag(CaseVals[i].second->getLHS()->getLocStart(),
613               diag::note_duplicate_case_prev);
614          // FIXME: We really want to remove the bogus case stmt from the
615          // substmt, but we have no way to do this right now.
616          CaseListIsErroneous = true;
617        }
618      }
619    }
620
621    // Detect duplicate case ranges, which usually don't exist at all in
622    // the first place.
623    if (!CaseRanges.empty()) {
624      // Sort all the case ranges by their low value so we can easily detect
625      // overlaps between ranges.
626      std::stable_sort(CaseRanges.begin(), CaseRanges.end());
627
628      // Scan the ranges, computing the high values and removing empty ranges.
629      std::vector<llvm::APSInt> HiVals;
630      for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
631        CaseStmt *CR = CaseRanges[i].second;
632        Expr *Hi = CR->getRHS();
633        llvm::APSInt HiVal = Hi->EvaluateAsInt(Context);
634
635        // Convert the value to the same width/sign as the condition.
636        ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned,
637                                           CR->getRHS()->getLocStart(),
638                                           diag::warn_case_value_overflow);
639
640        // If the LHS is not the same type as the condition, insert an implicit
641        // cast.
642        ImpCastExprToType(Hi, CondType, CastExpr::CK_IntegralCast);
643        CR->setRHS(Hi);
644
645        // If the low value is bigger than the high value, the case is empty.
646        if (CaseRanges[i].first > HiVal) {
647          Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range)
648            << SourceRange(CR->getLHS()->getLocStart(),
649                           CR->getRHS()->getLocEnd());
650          CaseRanges.erase(CaseRanges.begin()+i);
651          --i, --e;
652          continue;
653        }
654        HiVals.push_back(HiVal);
655      }
656
657      // Rescan the ranges, looking for overlap with singleton values and other
658      // ranges.  Since the range list is sorted, we only need to compare case
659      // ranges with their neighbors.
660      for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
661        llvm::APSInt &CRLo = CaseRanges[i].first;
662        llvm::APSInt &CRHi = HiVals[i];
663        CaseStmt *CR = CaseRanges[i].second;
664
665        // Check to see whether the case range overlaps with any
666        // singleton cases.
667        CaseStmt *OverlapStmt = 0;
668        llvm::APSInt OverlapVal(32);
669
670        // Find the smallest value >= the lower bound.  If I is in the
671        // case range, then we have overlap.
672        CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(),
673                                                  CaseVals.end(), CRLo,
674                                                  CaseCompareFunctor());
675        if (I != CaseVals.end() && I->first < CRHi) {
676          OverlapVal  = I->first;   // Found overlap with scalar.
677          OverlapStmt = I->second;
678        }
679
680        // Find the smallest value bigger than the upper bound.
681        I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor());
682        if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
683          OverlapVal  = (I-1)->first;      // Found overlap with scalar.
684          OverlapStmt = (I-1)->second;
685        }
686
687        // Check to see if this case stmt overlaps with the subsequent
688        // case range.
689        if (i && CRLo <= HiVals[i-1]) {
690          OverlapVal  = HiVals[i-1];       // Found overlap with range.
691          OverlapStmt = CaseRanges[i-1].second;
692        }
693
694        if (OverlapStmt) {
695          // If we have a duplicate, report it.
696          Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case)
697            << OverlapVal.toString(10);
698          Diag(OverlapStmt->getLHS()->getLocStart(),
699               diag::note_duplicate_case_prev);
700          // FIXME: We really want to remove the bogus case stmt from the
701          // substmt, but we have no way to do this right now.
702          CaseListIsErroneous = true;
703        }
704      }
705    }
706  }
707
708  // FIXME: If the case list was broken is some way, we don't have a good system
709  // to patch it up.  Instead, just return the whole substmt as broken.
710  if (CaseListIsErroneous)
711    return StmtError();
712
713  Switch.release();
714  return Owned(SS);
715}
716
717Action::OwningStmtResult
718Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, StmtArg Body) {
719  ExprArg CondArg(Cond.release());
720  Expr *condExpr = CondArg.takeAs<Expr>();
721  assert(condExpr && "ActOnWhileStmt(): missing expression");
722
723  if (CheckBooleanCondition(condExpr, WhileLoc)) {
724    CondArg = condExpr;
725    return StmtError();
726  }
727
728  Stmt *bodyStmt = Body.takeAs<Stmt>();
729  DiagnoseUnusedExprResult(bodyStmt);
730
731  CondArg.release();
732  return Owned(new (Context) WhileStmt(condExpr, bodyStmt, WhileLoc));
733}
734
735Action::OwningStmtResult
736Sema::ActOnDoStmt(SourceLocation DoLoc, StmtArg Body,
737                  SourceLocation WhileLoc, SourceLocation CondLParen,
738                  ExprArg Cond, SourceLocation CondRParen) {
739  Expr *condExpr = Cond.takeAs<Expr>();
740  assert(condExpr && "ActOnDoStmt(): missing expression");
741
742  if (CheckBooleanCondition(condExpr, DoLoc)) {
743    Cond = condExpr;
744    return StmtError();
745  }
746
747  Stmt *bodyStmt = Body.takeAs<Stmt>();
748  DiagnoseUnusedExprResult(bodyStmt);
749
750  Cond.release();
751  return Owned(new (Context) DoStmt(bodyStmt, condExpr, DoLoc,
752                                    WhileLoc, CondRParen));
753}
754
755Action::OwningStmtResult
756Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
757                   StmtArg first, ExprArg second, ExprArg third,
758                   SourceLocation RParenLoc, StmtArg body) {
759  Stmt *First  = static_cast<Stmt*>(first.get());
760  Expr *Second = second.takeAs<Expr>();
761  Expr *Third  = static_cast<Expr*>(third.get());
762  Stmt *Body  = static_cast<Stmt*>(body.get());
763
764  if (!getLangOptions().CPlusPlus) {
765    if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) {
766      // C99 6.8.5p3: The declaration part of a 'for' statement shall only
767      // declare identifiers for objects having storage class 'auto' or
768      // 'register'.
769      for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end();
770           DI!=DE; ++DI) {
771        VarDecl *VD = dyn_cast<VarDecl>(*DI);
772        if (VD && VD->isBlockVarDecl() && !VD->hasLocalStorage())
773          VD = 0;
774        if (VD == 0)
775          Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for);
776        // FIXME: mark decl erroneous!
777      }
778    }
779  }
780  if (Second && CheckBooleanCondition(Second, ForLoc)) {
781    second = Second;
782    return StmtError();
783  }
784
785  DiagnoseUnusedExprResult(First);
786  DiagnoseUnusedExprResult(Third);
787  DiagnoseUnusedExprResult(Body);
788
789  first.release();
790  third.release();
791  body.release();
792  return Owned(new (Context) ForStmt(First, Second, Third, Body, ForLoc,
793                                     LParenLoc, RParenLoc));
794}
795
796Action::OwningStmtResult
797Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
798                                 SourceLocation LParenLoc,
799                                 StmtArg first, ExprArg second,
800                                 SourceLocation RParenLoc, StmtArg body) {
801  Stmt *First  = static_cast<Stmt*>(first.get());
802  Expr *Second = static_cast<Expr*>(second.get());
803  Stmt *Body  = static_cast<Stmt*>(body.get());
804  if (First) {
805    QualType FirstType;
806    if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) {
807      if (!DS->isSingleDecl())
808        return StmtError(Diag((*DS->decl_begin())->getLocation(),
809                         diag::err_toomany_element_decls));
810
811      Decl *D = DS->getSingleDecl();
812      FirstType = cast<ValueDecl>(D)->getType();
813      // C99 6.8.5p3: The declaration part of a 'for' statement shall only
814      // declare identifiers for objects having storage class 'auto' or
815      // 'register'.
816      VarDecl *VD = cast<VarDecl>(D);
817      if (VD->isBlockVarDecl() && !VD->hasLocalStorage())
818        return StmtError(Diag(VD->getLocation(),
819                              diag::err_non_variable_decl_in_for));
820    } else {
821      if (cast<Expr>(First)->isLvalue(Context) != Expr::LV_Valid)
822        return StmtError(Diag(First->getLocStart(),
823                   diag::err_selector_element_not_lvalue)
824          << First->getSourceRange());
825
826      FirstType = static_cast<Expr*>(First)->getType();
827    }
828    if (!FirstType->isObjCObjectPointerType() &&
829        !FirstType->isBlockPointerType())
830        Diag(ForLoc, diag::err_selector_element_type)
831          << FirstType << First->getSourceRange();
832  }
833  if (Second) {
834    DefaultFunctionArrayConversion(Second);
835    QualType SecondType = Second->getType();
836    if (!SecondType->isObjCObjectPointerType())
837      Diag(ForLoc, diag::err_collection_expr_type)
838        << SecondType << Second->getSourceRange();
839  }
840  first.release();
841  second.release();
842  body.release();
843  return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body,
844                                                   ForLoc, RParenLoc));
845}
846
847Action::OwningStmtResult
848Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc,
849                    IdentifierInfo *LabelII) {
850  // If we are in a block, reject all gotos for now.
851  if (CurBlock)
852    return StmtError(Diag(GotoLoc, diag::err_goto_in_block));
853
854  // Look up the record for this label identifier.
855  LabelStmt *&LabelDecl = getLabelMap()[LabelII];
856
857  // If we haven't seen this label yet, create a forward reference.
858  if (LabelDecl == 0)
859    LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0);
860
861  return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc));
862}
863
864Action::OwningStmtResult
865Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
866                            ExprArg DestExp) {
867  // Convert operand to void*
868  Expr* E = DestExp.takeAs<Expr>();
869  if (!E->isTypeDependent()) {
870    QualType ETy = E->getType();
871    AssignConvertType ConvTy =
872      CheckSingleAssignmentConstraints(Context.VoidPtrTy, E);
873    if (DiagnoseAssignmentResult(ConvTy, StarLoc, Context.VoidPtrTy, ETy,
874                                 E, "passing"))
875      return StmtError();
876  }
877  return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E));
878}
879
880Action::OwningStmtResult
881Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
882  Scope *S = CurScope->getContinueParent();
883  if (!S) {
884    // C99 6.8.6.2p1: A break shall appear only in or as a loop body.
885    return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop));
886  }
887
888  return Owned(new (Context) ContinueStmt(ContinueLoc));
889}
890
891Action::OwningStmtResult
892Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
893  Scope *S = CurScope->getBreakParent();
894  if (!S) {
895    // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
896    return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch));
897  }
898
899  return Owned(new (Context) BreakStmt(BreakLoc));
900}
901
902/// ActOnBlockReturnStmt - Utility routine to figure out block's return type.
903///
904Action::OwningStmtResult
905Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
906  // If this is the first return we've seen in the block, infer the type of
907  // the block from it.
908  if (CurBlock->ReturnType.isNull()) {
909    if (RetValExp) {
910      // Don't call UsualUnaryConversions(), since we don't want to do
911      // integer promotions here.
912      DefaultFunctionArrayConversion(RetValExp);
913      CurBlock->ReturnType = RetValExp->getType();
914      if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) {
915        // We have to remove a 'const' added to copied-in variable which was
916        // part of the implementation spec. and not the actual qualifier for
917        // the variable.
918        if (CDRE->isConstQualAdded())
919           CurBlock->ReturnType.removeConst();
920      }
921    } else
922      CurBlock->ReturnType = Context.VoidTy;
923  }
924  QualType FnRetType = CurBlock->ReturnType;
925
926  if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) {
927    Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr)
928      << getCurFunctionOrMethodDecl()->getDeclName();
929    return StmtError();
930  }
931
932  // Otherwise, verify that this result type matches the previous one.  We are
933  // pickier with blocks than for normal functions because we don't have GCC
934  // compatibility to worry about here.
935  if (CurBlock->ReturnType->isVoidType()) {
936    if (RetValExp) {
937      Diag(ReturnLoc, diag::err_return_block_has_expr);
938      RetValExp->Destroy(Context);
939      RetValExp = 0;
940    }
941    return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp));
942  }
943
944  if (!RetValExp)
945    return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr));
946
947  if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) {
948    // we have a non-void block with an expression, continue checking
949    QualType RetValType = RetValExp->getType();
950
951    // C99 6.8.6.4p3(136): The return statement is not an assignment. The
952    // overlap restriction of subclause 6.5.16.1 does not apply to the case of
953    // function return.
954
955    // In C++ the return statement is handled via a copy initialization.
956    // the C version of which boils down to CheckSingleAssignmentConstraints.
957    // FIXME: Leaks RetValExp.
958    if (PerformCopyInitialization(RetValExp, FnRetType, "returning"))
959      return StmtError();
960
961    if (RetValExp) CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc);
962  }
963
964  return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp));
965}
966
967/// IsReturnCopyElidable - Whether returning @p RetExpr from a function that
968/// returns a @p RetType fulfills the criteria for copy elision (C++0x 12.8p15).
969static bool IsReturnCopyElidable(ASTContext &Ctx, QualType RetType,
970                                 Expr *RetExpr) {
971  QualType ExprType = RetExpr->getType();
972  // - in a return statement in a function with ...
973  // ... a class return type ...
974  if (!RetType->isRecordType())
975    return false;
976  // ... the same cv-unqualified type as the function return type ...
977  if (!Ctx.hasSameUnqualifiedType(RetType, ExprType))
978    return false;
979  // ... the expression is the name of a non-volatile automatic object ...
980  // We ignore parentheses here.
981  // FIXME: Is this compliant?
982  const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens());
983  if (!DR)
984    return false;
985  const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl());
986  if (!VD)
987    return false;
988  return VD->hasLocalStorage() && !VD->getType()->isReferenceType()
989    && !VD->getType().isVolatileQualified();
990}
991
992Action::OwningStmtResult
993Sema::ActOnReturnStmt(SourceLocation ReturnLoc, ExprArg rex) {
994  Expr *RetValExp = rex.takeAs<Expr>();
995  if (CurBlock)
996    return ActOnBlockReturnStmt(ReturnLoc, RetValExp);
997
998  QualType FnRetType;
999  if (const FunctionDecl *FD = getCurFunctionDecl()) {
1000    FnRetType = FD->getResultType();
1001    if (FD->hasAttr<NoReturnAttr>())
1002      Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr)
1003        << getCurFunctionOrMethodDecl()->getDeclName();
1004  } else if (ObjCMethodDecl *MD = getCurMethodDecl())
1005    FnRetType = MD->getResultType();
1006  else // If we don't have a function/method context, bail.
1007    return StmtError();
1008
1009  if (FnRetType->isVoidType()) {
1010    if (RetValExp && !RetValExp->isTypeDependent()) {
1011      // C99 6.8.6.4p1 (ext_ since GCC warns)
1012      unsigned D = diag::ext_return_has_expr;
1013      if (RetValExp->getType()->isVoidType())
1014        D = diag::ext_return_has_void_expr;
1015
1016      // return (some void expression); is legal in C++.
1017      if (D != diag::ext_return_has_void_expr ||
1018          !getLangOptions().CPlusPlus) {
1019        NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
1020        Diag(ReturnLoc, D)
1021          << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl)
1022          << RetValExp->getSourceRange();
1023      }
1024
1025      RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp, true);
1026    }
1027    return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp));
1028  }
1029
1030  if (!RetValExp && !FnRetType->isDependentType()) {
1031    unsigned DiagID = diag::warn_return_missing_expr;  // C90 6.6.6.4p4
1032    // C99 6.8.6.4p1 (ext_ since GCC warns)
1033    if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr;
1034
1035    if (FunctionDecl *FD = getCurFunctionDecl())
1036      Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/;
1037    else
1038      Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/;
1039    return Owned(new (Context) ReturnStmt(ReturnLoc, (Expr*)0));
1040  }
1041
1042  if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) {
1043    // we have a non-void function with an expression, continue checking
1044
1045    // C99 6.8.6.4p3(136): The return statement is not an assignment. The
1046    // overlap restriction of subclause 6.5.16.1 does not apply to the case of
1047    // function return.
1048
1049    // C++0x 12.8p15: When certain criteria are met, an implementation is
1050    //   allowed to omit the copy construction of a class object, [...]
1051    //   - in a return statement in a function with a class return type, when
1052    //     the expression is the name of a non-volatile automatic object with
1053    //     the same cv-unqualified type as the function return type, the copy
1054    //     operation can be omitted [...]
1055    // C++0x 12.8p16: When the criteria for elision of a copy operation are met
1056    //   and the object to be copied is designated by an lvalue, overload
1057    //   resolution to select the constructor for the copy is first performed
1058    //   as if the object were designated by an rvalue.
1059    // Note that we only compute Elidable if we're in C++0x, since we don't
1060    // care otherwise.
1061    bool Elidable = getLangOptions().CPlusPlus0x ?
1062                      IsReturnCopyElidable(Context, FnRetType, RetValExp) :
1063                      false;
1064
1065    // In C++ the return statement is handled via a copy initialization.
1066    // the C version of which boils down to CheckSingleAssignmentConstraints.
1067    // FIXME: Leaks RetValExp on error.
1068    if (PerformCopyInitialization(RetValExp, FnRetType, "returning", Elidable)){
1069      // We should still clean up our temporaries, even when we're failing!
1070      RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp, true);
1071      return StmtError();
1072    }
1073
1074    if (RetValExp) CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc);
1075  }
1076
1077  if (RetValExp)
1078    RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp, true);
1079  return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp));
1080}
1081
1082/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently
1083/// ignore "noop" casts in places where an lvalue is required by an inline asm.
1084/// We emulate this behavior when -fheinous-gnu-extensions is specified, but
1085/// provide a strong guidance to not use it.
1086///
1087/// This method checks to see if the argument is an acceptable l-value and
1088/// returns false if it is a case we can handle.
1089static bool CheckAsmLValue(const Expr *E, Sema &S) {
1090  if (E->isLvalue(S.Context) == Expr::LV_Valid)
1091    return false;  // Cool, this is an lvalue.
1092
1093  // Okay, this is not an lvalue, but perhaps it is the result of a cast that we
1094  // are supposed to allow.
1095  const Expr *E2 = E->IgnoreParenNoopCasts(S.Context);
1096  if (E != E2 && E2->isLvalue(S.Context) == Expr::LV_Valid) {
1097    if (!S.getLangOptions().HeinousExtensions)
1098      S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue)
1099        << E->getSourceRange();
1100    else
1101      S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue)
1102        << E->getSourceRange();
1103    // Accept, even if we emitted an error diagnostic.
1104    return false;
1105  }
1106
1107  // None of the above, just randomly invalid non-lvalue.
1108  return true;
1109}
1110
1111
1112Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc,
1113                                          bool IsSimple,
1114                                          bool IsVolatile,
1115                                          unsigned NumOutputs,
1116                                          unsigned NumInputs,
1117                                          std::string *Names,
1118                                          MultiExprArg constraints,
1119                                          MultiExprArg exprs,
1120                                          ExprArg asmString,
1121                                          MultiExprArg clobbers,
1122                                          SourceLocation RParenLoc) {
1123  unsigned NumClobbers = clobbers.size();
1124  StringLiteral **Constraints =
1125    reinterpret_cast<StringLiteral**>(constraints.get());
1126  Expr **Exprs = reinterpret_cast<Expr **>(exprs.get());
1127  StringLiteral *AsmString = cast<StringLiteral>((Expr *)asmString.get());
1128  StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get());
1129
1130  llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
1131
1132  // The parser verifies that there is a string literal here.
1133  if (AsmString->isWide())
1134    return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character)
1135      << AsmString->getSourceRange());
1136
1137  for (unsigned i = 0; i != NumOutputs; i++) {
1138    StringLiteral *Literal = Constraints[i];
1139    if (Literal->isWide())
1140      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
1141        << Literal->getSourceRange());
1142
1143    TargetInfo::ConstraintInfo Info(Literal->getStrData(),
1144                                    Literal->getByteLength(),
1145                                    Names[i]);
1146    if (!Context.Target.validateOutputConstraint(Info))
1147      return StmtError(Diag(Literal->getLocStart(),
1148                            diag::err_asm_invalid_output_constraint)
1149                       << Info.getConstraintStr());
1150
1151    // Check that the output exprs are valid lvalues.
1152    Expr *OutputExpr = Exprs[i];
1153    if (CheckAsmLValue(OutputExpr, *this)) {
1154      return StmtError(Diag(OutputExpr->getLocStart(),
1155                  diag::err_asm_invalid_lvalue_in_output)
1156        << OutputExpr->getSourceRange());
1157    }
1158
1159    OutputConstraintInfos.push_back(Info);
1160  }
1161
1162  llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
1163
1164  for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
1165    StringLiteral *Literal = Constraints[i];
1166    if (Literal->isWide())
1167      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
1168        << Literal->getSourceRange());
1169
1170    TargetInfo::ConstraintInfo Info(Literal->getStrData(),
1171                                    Literal->getByteLength(),
1172                                    Names[i]);
1173    if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(),
1174                                                NumOutputs, Info)) {
1175      return StmtError(Diag(Literal->getLocStart(),
1176                            diag::err_asm_invalid_input_constraint)
1177                       << Info.getConstraintStr());
1178    }
1179
1180    Expr *InputExpr = Exprs[i];
1181
1182    // Only allow void types for memory constraints.
1183    if (Info.allowsMemory() && !Info.allowsRegister()) {
1184      if (CheckAsmLValue(InputExpr, *this))
1185        return StmtError(Diag(InputExpr->getLocStart(),
1186                              diag::err_asm_invalid_lvalue_in_input)
1187                         << Info.getConstraintStr()
1188                         << InputExpr->getSourceRange());
1189    }
1190
1191    if (Info.allowsRegister()) {
1192      if (InputExpr->getType()->isVoidType()) {
1193        return StmtError(Diag(InputExpr->getLocStart(),
1194                              diag::err_asm_invalid_type_in_input)
1195          << InputExpr->getType() << Info.getConstraintStr()
1196          << InputExpr->getSourceRange());
1197      }
1198    }
1199
1200    DefaultFunctionArrayConversion(Exprs[i]);
1201
1202    InputConstraintInfos.push_back(Info);
1203  }
1204
1205  // Check that the clobbers are valid.
1206  for (unsigned i = 0; i != NumClobbers; i++) {
1207    StringLiteral *Literal = Clobbers[i];
1208    if (Literal->isWide())
1209      return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character)
1210        << Literal->getSourceRange());
1211
1212    std::string Clobber(Literal->getStrData(),
1213                        Literal->getStrData() +
1214                        Literal->getByteLength());
1215
1216    if (!Context.Target.isValidGCCRegisterName(Clobber.c_str()))
1217      return StmtError(Diag(Literal->getLocStart(),
1218                  diag::err_asm_unknown_register_name) << Clobber);
1219  }
1220
1221  constraints.release();
1222  exprs.release();
1223  asmString.release();
1224  clobbers.release();
1225  AsmStmt *NS =
1226    new (Context) AsmStmt(AsmLoc, IsSimple, IsVolatile, NumOutputs, NumInputs,
1227                          Names, Constraints, Exprs, AsmString, NumClobbers,
1228                          Clobbers, RParenLoc);
1229  // Validate the asm string, ensuring it makes sense given the operands we
1230  // have.
1231  llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces;
1232  unsigned DiagOffs;
1233  if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) {
1234    Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID)
1235           << AsmString->getSourceRange();
1236    DeleteStmt(NS);
1237    return StmtError();
1238  }
1239
1240  // Validate tied input operands for type mismatches.
1241  for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
1242    TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
1243
1244    // If this is a tied constraint, verify that the output and input have
1245    // either exactly the same type, or that they are int/ptr operands with the
1246    // same size (int/long, int*/long, are ok etc).
1247    if (!Info.hasTiedOperand()) continue;
1248
1249    unsigned TiedTo = Info.getTiedOperand();
1250    Expr *OutputExpr = Exprs[TiedTo];
1251    Expr *InputExpr = Exprs[i+NumOutputs];
1252    QualType InTy = InputExpr->getType();
1253    QualType OutTy = OutputExpr->getType();
1254    if (Context.hasSameType(InTy, OutTy))
1255      continue;  // All types can be tied to themselves.
1256
1257    // Int/ptr operands have some special cases that we allow.
1258    if ((OutTy->isIntegerType() || OutTy->isPointerType()) &&
1259        (InTy->isIntegerType() || InTy->isPointerType())) {
1260
1261      // They are ok if they are the same size.  Tying void* to int is ok if
1262      // they are the same size, for example.  This also allows tying void* to
1263      // int*.
1264      uint64_t OutSize = Context.getTypeSize(OutTy);
1265      uint64_t InSize = Context.getTypeSize(InTy);
1266      if (OutSize == InSize)
1267        continue;
1268
1269      // If the smaller input/output operand is not mentioned in the asm string,
1270      // then we can promote it and the asm string won't notice.  Check this
1271      // case now.
1272      bool SmallerValueMentioned = false;
1273      for (unsigned p = 0, e = Pieces.size(); p != e; ++p) {
1274        AsmStmt::AsmStringPiece &Piece = Pieces[p];
1275        if (!Piece.isOperand()) continue;
1276
1277        // If this is a reference to the input and if the input was the smaller
1278        // one, then we have to reject this asm.
1279        if (Piece.getOperandNo() == i+NumOutputs) {
1280          if (InSize < OutSize) {
1281            SmallerValueMentioned = true;
1282            break;
1283          }
1284        }
1285
1286        // If this is a reference to the input and if the input was the smaller
1287        // one, then we have to reject this asm.
1288        if (Piece.getOperandNo() == TiedTo) {
1289          if (InSize > OutSize) {
1290            SmallerValueMentioned = true;
1291            break;
1292          }
1293        }
1294      }
1295
1296      // If the smaller value wasn't mentioned in the asm string, and if the
1297      // output was a register, just extend the shorter one to the size of the
1298      // larger one.
1299      if (!SmallerValueMentioned &&
1300          OutputConstraintInfos[TiedTo].allowsRegister())
1301        continue;
1302    }
1303
1304    Diag(InputExpr->getLocStart(),
1305         diag::err_asm_tying_incompatible_types)
1306      << InTy << OutTy << OutputExpr->getSourceRange()
1307      << InputExpr->getSourceRange();
1308    DeleteStmt(NS);
1309    return StmtError();
1310  }
1311
1312  return Owned(NS);
1313}
1314
1315Action::OwningStmtResult
1316Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
1317                           SourceLocation RParen, DeclPtrTy Parm,
1318                           StmtArg Body, StmtArg catchList) {
1319  Stmt *CatchList = catchList.takeAs<Stmt>();
1320  ParmVarDecl *PVD = cast_or_null<ParmVarDecl>(Parm.getAs<Decl>());
1321
1322  // PVD == 0 implies @catch(...).
1323  if (PVD) {
1324    // If we already know the decl is invalid, reject it.
1325    if (PVD->isInvalidDecl())
1326      return StmtError();
1327
1328    if (!PVD->getType()->isObjCObjectPointerType())
1329      return StmtError(Diag(PVD->getLocation(),
1330                       diag::err_catch_param_not_objc_type));
1331    if (PVD->getType()->isObjCQualifiedIdType())
1332      return StmtError(Diag(PVD->getLocation(),
1333                       diag::err_illegal_qualifiers_on_catch_parm));
1334  }
1335
1336  ObjCAtCatchStmt *CS = new (Context) ObjCAtCatchStmt(AtLoc, RParen,
1337    PVD, Body.takeAs<Stmt>(), CatchList);
1338  return Owned(CatchList ? CatchList : CS);
1339}
1340
1341Action::OwningStmtResult
1342Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, StmtArg Body) {
1343  return Owned(new (Context) ObjCAtFinallyStmt(AtLoc,
1344                                           static_cast<Stmt*>(Body.release())));
1345}
1346
1347Action::OwningStmtResult
1348Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc,
1349                         StmtArg Try, StmtArg Catch, StmtArg Finally) {
1350  CurFunctionNeedsScopeChecking = true;
1351  return Owned(new (Context) ObjCAtTryStmt(AtLoc, Try.takeAs<Stmt>(),
1352                                           Catch.takeAs<Stmt>(),
1353                                           Finally.takeAs<Stmt>()));
1354}
1355
1356Action::OwningStmtResult
1357Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg expr,Scope *CurScope) {
1358  Expr *ThrowExpr = expr.takeAs<Expr>();
1359  if (!ThrowExpr) {
1360    // @throw without an expression designates a rethrow (which much occur
1361    // in the context of an @catch clause).
1362    Scope *AtCatchParent = CurScope;
1363    while (AtCatchParent && !AtCatchParent->isAtCatchScope())
1364      AtCatchParent = AtCatchParent->getParent();
1365    if (!AtCatchParent)
1366      return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch));
1367  } else {
1368    QualType ThrowType = ThrowExpr->getType();
1369    // Make sure the expression type is an ObjC pointer or "void *".
1370    if (!ThrowType->isObjCObjectPointerType()) {
1371      const PointerType *PT = ThrowType->getAs<PointerType>();
1372      if (!PT || !PT->getPointeeType()->isVoidType())
1373        return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object)
1374                        << ThrowExpr->getType() << ThrowExpr->getSourceRange());
1375    }
1376  }
1377  return Owned(new (Context) ObjCAtThrowStmt(AtLoc, ThrowExpr));
1378}
1379
1380Action::OwningStmtResult
1381Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprArg SynchExpr,
1382                                  StmtArg SynchBody) {
1383  CurFunctionNeedsScopeChecking = true;
1384
1385  // Make sure the expression type is an ObjC pointer or "void *".
1386  Expr *SyncExpr = static_cast<Expr*>(SynchExpr.get());
1387  if (!SyncExpr->getType()->isObjCObjectPointerType()) {
1388    const PointerType *PT = SyncExpr->getType()->getAs<PointerType>();
1389    if (!PT || !PT->getPointeeType()->isVoidType())
1390      return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object)
1391                       << SyncExpr->getType() << SyncExpr->getSourceRange());
1392  }
1393
1394  return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc,
1395                                                    SynchExpr.takeAs<Stmt>(),
1396                                                    SynchBody.takeAs<Stmt>()));
1397}
1398
1399/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
1400/// and creates a proper catch handler from them.
1401Action::OwningStmtResult
1402Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclPtrTy ExDecl,
1403                         StmtArg HandlerBlock) {
1404  // There's nothing to test that ActOnExceptionDecl didn't already test.
1405  return Owned(new (Context) CXXCatchStmt(CatchLoc,
1406                                  cast_or_null<VarDecl>(ExDecl.getAs<Decl>()),
1407                                          HandlerBlock.takeAs<Stmt>()));
1408}
1409
1410class TypeWithHandler {
1411  QualType t;
1412  CXXCatchStmt *stmt;
1413public:
1414  TypeWithHandler(const QualType &type, CXXCatchStmt *statement)
1415  : t(type), stmt(statement) {}
1416
1417  // An arbitrary order is fine as long as it places identical
1418  // types next to each other.
1419  bool operator<(const TypeWithHandler &y) const {
1420    if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr())
1421      return true;
1422    if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr())
1423      return false;
1424    else
1425      return getTypeSpecStartLoc() < y.getTypeSpecStartLoc();
1426  }
1427
1428  bool operator==(const TypeWithHandler& other) const {
1429    return t == other.t;
1430  }
1431
1432  QualType getQualType() const { return t; }
1433  CXXCatchStmt *getCatchStmt() const { return stmt; }
1434  SourceLocation getTypeSpecStartLoc() const {
1435    return stmt->getExceptionDecl()->getTypeSpecStartLoc();
1436  }
1437};
1438
1439/// ActOnCXXTryBlock - Takes a try compound-statement and a number of
1440/// handlers and creates a try statement from them.
1441Action::OwningStmtResult
1442Sema::ActOnCXXTryBlock(SourceLocation TryLoc, StmtArg TryBlock,
1443                       MultiStmtArg RawHandlers) {
1444  unsigned NumHandlers = RawHandlers.size();
1445  assert(NumHandlers > 0 &&
1446         "The parser shouldn't call this if there are no handlers.");
1447  Stmt **Handlers = reinterpret_cast<Stmt**>(RawHandlers.get());
1448
1449  llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers;
1450
1451  for (unsigned i = 0; i < NumHandlers; ++i) {
1452    CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]);
1453    if (!Handler->getExceptionDecl()) {
1454      if (i < NumHandlers - 1)
1455        return StmtError(Diag(Handler->getLocStart(),
1456                              diag::err_early_catch_all));
1457
1458      continue;
1459    }
1460
1461    const QualType CaughtType = Handler->getCaughtType();
1462    const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType);
1463    TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler));
1464  }
1465
1466  // Detect handlers for the same type as an earlier one.
1467  if (NumHandlers > 1) {
1468    llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end());
1469
1470    TypeWithHandler prev = TypesWithHandlers[0];
1471    for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) {
1472      TypeWithHandler curr = TypesWithHandlers[i];
1473
1474      if (curr == prev) {
1475        Diag(curr.getTypeSpecStartLoc(),
1476             diag::warn_exception_caught_by_earlier_handler)
1477          << curr.getCatchStmt()->getCaughtType().getAsString();
1478        Diag(prev.getTypeSpecStartLoc(),
1479             diag::note_previous_exception_handler)
1480          << prev.getCatchStmt()->getCaughtType().getAsString();
1481      }
1482
1483      prev = curr;
1484    }
1485  }
1486
1487  // FIXME: We should detect handlers that cannot catch anything because an
1488  // earlier handler catches a superclass. Need to find a method that is not
1489  // quadratic for this.
1490  // Neither of these are explicitly forbidden, but every compiler detects them
1491  // and warns.
1492
1493  CurFunctionNeedsScopeChecking = true;
1494  RawHandlers.release();
1495  return Owned(new (Context) CXXTryStmt(TryLoc,
1496                                        static_cast<Stmt*>(TryBlock.release()),
1497                                        Handlers, NumHandlers));
1498}
1499