SemaStmt.cpp revision 248a753f6b670692523c99afaeb8fe98f7ae3ca7 
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/ASTContext.h"
16#include "clang/AST/Expr.h"
17#include "clang/AST/Stmt.h"
18#include "clang/Parse/Scope.h"
19#include "clang/Basic/TargetInfo.h"
20#include "clang/Basic/Diagnostic.h"
21#include "clang/Basic/LangOptions.h"
22#include "llvm/ADT/SmallString.h"
23using namespace clang;
24
25Sema::StmtResult Sema::ActOnExprStmt(ExprTy *expr) {
26  Expr *E = static_cast<Expr*>(expr);
27  assert(E && "ActOnExprStmt(): missing expression");
28  return E;
29}
30
31
32Sema::StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc) {
33  return new NullStmt(SemiLoc);
34}
35
36Sema::StmtResult Sema::ActOnDeclStmt(DeclTy *decl, SourceLocation StartLoc,
37                                     SourceLocation EndLoc) {
38  if (decl == 0)
39    return true;
40
41  ScopedDecl *SD = cast<ScopedDecl>(static_cast<Decl *>(decl));
42  return new DeclStmt(SD, StartLoc, EndLoc);
43}
44
45Action::StmtResult
46Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
47                        StmtTy **elts, unsigned NumElts, bool isStmtExpr) {
48  Stmt **Elts = reinterpret_cast<Stmt**>(elts);
49  // If we're in C89 mode, check that we don't have any decls after stmts.  If
50  // so, emit an extension diagnostic.
51  if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) {
52    // Note that __extension__ can be around a decl.
53    unsigned i = 0;
54    // Skip over all declarations.
55    for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i)
56      /*empty*/;
57
58    // We found the end of the list or a statement.  Scan for another declstmt.
59    for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i)
60      /*empty*/;
61
62    if (i != NumElts) {
63      ScopedDecl *D = cast<DeclStmt>(Elts[i])->getDecl();
64      Diag(D->getLocation(), diag::ext_mixed_decls_code);
65    }
66  }
67  // Warn about unused expressions in statements.
68  for (unsigned i = 0; i != NumElts; ++i) {
69    Expr *E = dyn_cast<Expr>(Elts[i]);
70    if (!E) continue;
71
72    // Warn about expressions with unused results.
73    if (E->hasLocalSideEffect() || E->getType()->isVoidType())
74      continue;
75
76    // The last expr in a stmt expr really is used.
77    if (isStmtExpr && i == NumElts-1)
78      continue;
79
80    /// DiagnoseDeadExpr - This expression is side-effect free and evaluated in
81    /// a context where the result is unused.  Emit a diagnostic to warn about
82    /// this.
83    if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E))
84      Diag(BO->getOperatorLoc(), diag::warn_unused_expr,
85           BO->getLHS()->getSourceRange(), BO->getRHS()->getSourceRange());
86    else if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E))
87      Diag(UO->getOperatorLoc(), diag::warn_unused_expr,
88           UO->getSubExpr()->getSourceRange());
89    else
90      Diag(E->getExprLoc(), diag::warn_unused_expr, E->getSourceRange());
91  }
92
93  return new CompoundStmt(Elts, NumElts, L, R);
94}
95
96Action::StmtResult
97Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprTy *lhsval,
98                    SourceLocation DotDotDotLoc, ExprTy *rhsval,
99                    SourceLocation ColonLoc, StmtTy *subStmt) {
100  Stmt *SubStmt = static_cast<Stmt*>(subStmt);
101  Expr *LHSVal = ((Expr *)lhsval), *RHSVal = ((Expr *)rhsval);
102  assert((LHSVal != 0) && "missing expression in case statement");
103
104  SourceLocation ExpLoc;
105  // C99 6.8.4.2p3: The expression shall be an integer constant.
106  if (!LHSVal->isIntegerConstantExpr(Context, &ExpLoc)) {
107    Diag(ExpLoc, diag::err_case_label_not_integer_constant_expr,
108         LHSVal->getSourceRange());
109    return SubStmt;
110  }
111
112  // GCC extension: The expression shall be an integer constant.
113  if (RHSVal && !RHSVal->isIntegerConstantExpr(Context, &ExpLoc)) {
114    Diag(ExpLoc, diag::err_case_label_not_integer_constant_expr,
115         RHSVal->getSourceRange());
116    RHSVal = 0;  // Recover by just forgetting about it.
117  }
118
119  if (SwitchStack.empty()) {
120    Diag(CaseLoc, diag::err_case_not_in_switch);
121    return SubStmt;
122  }
123
124  CaseStmt *CS = new CaseStmt(LHSVal, RHSVal, SubStmt, CaseLoc);
125  SwitchStack.back()->addSwitchCase(CS);
126  return CS;
127}
128
129Action::StmtResult
130Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
131                       StmtTy *subStmt, Scope *CurScope) {
132  Stmt *SubStmt = static_cast<Stmt*>(subStmt);
133
134  if (SwitchStack.empty()) {
135    Diag(DefaultLoc, diag::err_default_not_in_switch);
136    return SubStmt;
137  }
138
139  DefaultStmt *DS = new DefaultStmt(DefaultLoc, SubStmt);
140  SwitchStack.back()->addSwitchCase(DS);
141
142  return DS;
143}
144
145Action::StmtResult
146Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II,
147                     SourceLocation ColonLoc, StmtTy *subStmt) {
148  Stmt *SubStmt = static_cast<Stmt*>(subStmt);
149  // Look up the record for this label identifier.
150  LabelStmt *&LabelDecl = LabelMap[II];
151
152  // If not forward referenced or defined already, just create a new LabelStmt.
153  if (LabelDecl == 0)
154    return LabelDecl = new LabelStmt(IdentLoc, II, SubStmt);
155
156  assert(LabelDecl->getID() == II && "Label mismatch!");
157
158  // Otherwise, this label was either forward reference or multiply defined.  If
159  // multiply defined, reject it now.
160  if (LabelDecl->getSubStmt()) {
161    Diag(IdentLoc, diag::err_redefinition_of_label, LabelDecl->getName());
162    Diag(LabelDecl->getIdentLoc(), diag::err_previous_definition);
163    return SubStmt;
164  }
165
166  // Otherwise, this label was forward declared, and we just found its real
167  // definition.  Fill in the forward definition and return it.
168  LabelDecl->setIdentLoc(IdentLoc);
169  LabelDecl->setSubStmt(SubStmt);
170  return LabelDecl;
171}
172
173Action::StmtResult
174Sema::ActOnIfStmt(SourceLocation IfLoc, ExprTy *CondVal,
175                  StmtTy *ThenVal, SourceLocation ElseLoc,
176                  StmtTy *ElseVal) {
177  Expr *condExpr = (Expr *)CondVal;
178  Stmt *thenStmt = (Stmt *)ThenVal;
179
180  assert(condExpr && "ActOnIfStmt(): missing expression");
181
182  DefaultFunctionArrayConversion(condExpr);
183  QualType condType = condExpr->getType();
184
185  if (!condType->isScalarType()) // C99 6.8.4.1p1
186    return Diag(IfLoc, diag::err_typecheck_statement_requires_scalar,
187             condType.getAsString(), condExpr->getSourceRange());
188
189  // Warn if the if block has a null body without an else value.
190  // this helps prevent bugs due to typos, such as
191  // if (condition);
192  //   do_stuff();
193  if (!ElseVal) {
194    if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt))
195      Diag(stmt->getSemiLoc(), diag::warn_empty_if_body);
196  }
197
198  return new IfStmt(IfLoc, condExpr, thenStmt, (Stmt*)ElseVal);
199}
200
201Action::StmtResult
202Sema::ActOnStartOfSwitchStmt(ExprTy *cond) {
203  Expr *Cond = static_cast<Expr*>(cond);
204
205  // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
206  UsualUnaryConversions(Cond);
207
208  SwitchStmt *SS = new SwitchStmt(Cond);
209  SwitchStack.push_back(SS);
210  return SS;
211}
212
213/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have
214/// the specified width and sign.  If an overflow occurs, detect it and emit
215/// the specified diagnostic.
216void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val,
217                                              unsigned NewWidth, bool NewSign,
218                                              SourceLocation Loc,
219                                              unsigned DiagID) {
220  // Perform a conversion to the promoted condition type if needed.
221  if (NewWidth > Val.getBitWidth()) {
222    // If this is an extension, just do it.
223    llvm::APSInt OldVal(Val);
224    Val.extend(NewWidth);
225
226    // If the input was signed and negative and the output is unsigned,
227    // warn.
228    if (!NewSign && OldVal.isSigned() && OldVal.isNegative())
229      Diag(Loc, DiagID, OldVal.toString(), Val.toString());
230
231    Val.setIsSigned(NewSign);
232  } else if (NewWidth < Val.getBitWidth()) {
233    // If this is a truncation, check for overflow.
234    llvm::APSInt ConvVal(Val);
235    ConvVal.trunc(NewWidth);
236    ConvVal.setIsSigned(NewSign);
237    ConvVal.extend(Val.getBitWidth());
238    ConvVal.setIsSigned(Val.isSigned());
239    if (ConvVal != Val)
240      Diag(Loc, DiagID, Val.toString(), ConvVal.toString());
241
242    // Regardless of whether a diagnostic was emitted, really do the
243    // truncation.
244    Val.trunc(NewWidth);
245    Val.setIsSigned(NewSign);
246  } else if (NewSign != Val.isSigned()) {
247    // Convert the sign to match the sign of the condition.  This can cause
248    // overflow as well: unsigned(INTMIN)
249    llvm::APSInt OldVal(Val);
250    Val.setIsSigned(NewSign);
251
252    if (Val.isNegative())  // Sign bit changes meaning.
253      Diag(Loc, DiagID, OldVal.toString(), Val.toString());
254  }
255}
256
257namespace {
258  struct CaseCompareFunctor {
259    bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
260                    const llvm::APSInt &RHS) {
261      return LHS.first < RHS;
262    }
263    bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
264                    const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
265      return LHS.first < RHS.first;
266    }
267    bool operator()(const llvm::APSInt &LHS,
268                    const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
269      return LHS < RHS.first;
270    }
271  };
272}
273
274/// CmpCaseVals - Comparison predicate for sorting case values.
275///
276static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
277                        const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
278  if (lhs.first < rhs.first)
279    return true;
280
281  if (lhs.first == rhs.first &&
282      lhs.second->getCaseLoc().getRawEncoding()
283       < rhs.second->getCaseLoc().getRawEncoding())
284    return true;
285  return false;
286}
287
288Action::StmtResult
289Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, StmtTy *Switch,
290                            ExprTy *Body) {
291  Stmt *BodyStmt = (Stmt*)Body;
292
293  SwitchStmt *SS = SwitchStack.back();
294  assert(SS == (SwitchStmt*)Switch && "switch stack missing push/pop!");
295
296  SS->setBody(BodyStmt, SwitchLoc);
297  SwitchStack.pop_back();
298
299  Expr *CondExpr = SS->getCond();
300  QualType CondType = CondExpr->getType();
301
302  if (!CondType->isIntegerType()) { // C99 6.8.4.2p1
303    Diag(SwitchLoc, diag::err_typecheck_statement_requires_integer,
304         CondType.getAsString(), CondExpr->getSourceRange());
305    return true;
306  }
307
308  // Get the bitwidth of the switched-on value before promotions.  We must
309  // convert the integer case values to this width before comparison.
310  unsigned CondWidth = static_cast<unsigned>(Context.getTypeSize(CondType));
311  bool CondIsSigned = CondType->isSignedIntegerType();
312
313  // Accumulate all of the case values in a vector so that we can sort them
314  // and detect duplicates.  This vector contains the APInt for the case after
315  // it has been converted to the condition type.
316  typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
317  CaseValsTy CaseVals;
318
319  // Keep track of any GNU case ranges we see.  The APSInt is the low value.
320  std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRanges;
321
322  DefaultStmt *TheDefaultStmt = 0;
323
324  bool CaseListIsErroneous = false;
325
326  for (SwitchCase *SC = SS->getSwitchCaseList(); SC;
327       SC = SC->getNextSwitchCase()) {
328
329    if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) {
330      if (TheDefaultStmt) {
331        Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
332        Diag(TheDefaultStmt->getDefaultLoc(), diag::err_first_label);
333
334        // FIXME: Remove the default statement from the switch block so that
335        // we'll return a valid AST.  This requires recursing down the
336        // AST and finding it, not something we are set up to do right now.  For
337        // now, just lop the entire switch stmt out of the AST.
338        CaseListIsErroneous = true;
339      }
340      TheDefaultStmt = DS;
341
342    } else {
343      CaseStmt *CS = cast<CaseStmt>(SC);
344
345      // We already verified that the expression has a i-c-e value (C99
346      // 6.8.4.2p3) - get that value now.
347      llvm::APSInt LoVal(32);
348      Expr *Lo = CS->getLHS();
349      Lo->isIntegerConstantExpr(LoVal, Context);
350
351      // Convert the value to the same width/sign as the condition.
352      ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned,
353                                         CS->getLHS()->getLocStart(),
354                                         diag::warn_case_value_overflow);
355
356      // If the LHS is not the same type as the condition, insert an implicit
357      // cast.
358      ImpCastExprToType(Lo, CondType);
359      CS->setLHS(Lo);
360
361      // If this is a case range, remember it in CaseRanges, otherwise CaseVals.
362      if (CS->getRHS())
363        CaseRanges.push_back(std::make_pair(LoVal, CS));
364      else
365        CaseVals.push_back(std::make_pair(LoVal, CS));
366    }
367  }
368
369  // Sort all the scalar case values so we can easily detect duplicates.
370  std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals);
371
372  if (!CaseVals.empty()) {
373    for (unsigned i = 0, e = CaseVals.size()-1; i != e; ++i) {
374      if (CaseVals[i].first == CaseVals[i+1].first) {
375        // If we have a duplicate, report it.
376        Diag(CaseVals[i+1].second->getLHS()->getLocStart(),
377             diag::err_duplicate_case, CaseVals[i].first.toString());
378        Diag(CaseVals[i].second->getLHS()->getLocStart(),
379             diag::err_duplicate_case_prev);
380        // FIXME: We really want to remove the bogus case stmt from the substmt,
381        // but we have no way to do this right now.
382        CaseListIsErroneous = true;
383      }
384    }
385  }
386
387  // Detect duplicate case ranges, which usually don't exist at all in the first
388  // place.
389  if (!CaseRanges.empty()) {
390    // Sort all the case ranges by their low value so we can easily detect
391    // overlaps between ranges.
392    std::stable_sort(CaseRanges.begin(), CaseRanges.end());
393
394    // Scan the ranges, computing the high values and removing empty ranges.
395    std::vector<llvm::APSInt> HiVals;
396    for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
397      CaseStmt *CR = CaseRanges[i].second;
398      llvm::APSInt HiVal(32);
399      Expr *Hi = CR->getRHS();
400      Hi->isIntegerConstantExpr(HiVal, Context);
401
402      // Convert the value to the same width/sign as the condition.
403      ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned,
404                                         CR->getRHS()->getLocStart(),
405                                         diag::warn_case_value_overflow);
406
407      // If the LHS is not the same type as the condition, insert an implicit
408      // cast.
409      ImpCastExprToType(Hi, CondType);
410      CR->setRHS(Hi);
411
412      // If the low value is bigger than the high value, the case is empty.
413      if (CaseRanges[i].first > HiVal) {
414        Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range,
415             SourceRange(CR->getLHS()->getLocStart(),
416                         CR->getRHS()->getLocEnd()));
417        CaseRanges.erase(CaseRanges.begin()+i);
418        --i, --e;
419        continue;
420      }
421      HiVals.push_back(HiVal);
422    }
423
424    // Rescan the ranges, looking for overlap with singleton values and other
425    // ranges.  Since the range list is sorted, we only need to compare case
426    // ranges with their neighbors.
427    for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
428      llvm::APSInt &CRLo = CaseRanges[i].first;
429      llvm::APSInt &CRHi = HiVals[i];
430      CaseStmt *CR = CaseRanges[i].second;
431
432      // Check to see whether the case range overlaps with any singleton cases.
433      CaseStmt *OverlapStmt = 0;
434      llvm::APSInt OverlapVal(32);
435
436      // Find the smallest value >= the lower bound.  If I is in the case range,
437      // then we have overlap.
438      CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(),
439                                                CaseVals.end(), CRLo,
440                                                CaseCompareFunctor());
441      if (I != CaseVals.end() && I->first < CRHi) {
442        OverlapVal  = I->first;   // Found overlap with scalar.
443        OverlapStmt = I->second;
444      }
445
446      // Find the smallest value bigger than the upper bound.
447      I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor());
448      if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
449        OverlapVal  = (I-1)->first;      // Found overlap with scalar.
450        OverlapStmt = (I-1)->second;
451      }
452
453      // Check to see if this case stmt overlaps with the subsequent case range.
454      if (i && CRLo <= HiVals[i-1]) {
455        OverlapVal  = HiVals[i-1];       // Found overlap with range.
456        OverlapStmt = CaseRanges[i-1].second;
457      }
458
459      if (OverlapStmt) {
460        // If we have a duplicate, report it.
461        Diag(CR->getLHS()->getLocStart(),
462             diag::err_duplicate_case, OverlapVal.toString());
463        Diag(OverlapStmt->getLHS()->getLocStart(),
464             diag::err_duplicate_case_prev);
465        // FIXME: We really want to remove the bogus case stmt from the substmt,
466        // but we have no way to do this right now.
467        CaseListIsErroneous = true;
468      }
469    }
470  }
471
472  // FIXME: If the case list was broken is some way, we don't have a good system
473  // to patch it up.  Instead, just return the whole substmt as broken.
474  if (CaseListIsErroneous)
475    return true;
476
477  return SS;
478}
479
480Action::StmtResult
481Sema::ActOnWhileStmt(SourceLocation WhileLoc, ExprTy *Cond, StmtTy *Body) {
482  Expr *condExpr = (Expr *)Cond;
483  assert(condExpr && "ActOnWhileStmt(): missing expression");
484
485  DefaultFunctionArrayConversion(condExpr);
486  QualType condType = condExpr->getType();
487
488  if (!condType->isScalarType()) // C99 6.8.5p2
489    return Diag(WhileLoc, diag::err_typecheck_statement_requires_scalar,
490             condType.getAsString(), condExpr->getSourceRange());
491
492  return new WhileStmt(condExpr, (Stmt*)Body, WhileLoc);
493}
494
495Action::StmtResult
496Sema::ActOnDoStmt(SourceLocation DoLoc, StmtTy *Body,
497                  SourceLocation WhileLoc, ExprTy *Cond) {
498  Expr *condExpr = (Expr *)Cond;
499  assert(condExpr && "ActOnDoStmt(): missing expression");
500
501  DefaultFunctionArrayConversion(condExpr);
502  QualType condType = condExpr->getType();
503
504  if (!condType->isScalarType()) // C99 6.8.5p2
505    return Diag(DoLoc, diag::err_typecheck_statement_requires_scalar,
506             condType.getAsString(), condExpr->getSourceRange());
507
508  return new DoStmt((Stmt*)Body, condExpr, DoLoc);
509}
510
511Action::StmtResult
512Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
513                   StmtTy *first, ExprTy *second, ExprTy *third,
514                   SourceLocation RParenLoc, StmtTy *body) {
515  Stmt *First  = static_cast<Stmt*>(first);
516  Expr *Second = static_cast<Expr*>(second);
517  Expr *Third  = static_cast<Expr*>(third);
518  Stmt *Body  = static_cast<Stmt*>(body);
519
520  if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) {
521    // C99 6.8.5p3: The declaration part of a 'for' statement shall only declare
522    // identifiers for objects having storage class 'auto' or 'register'.
523    for (ScopedDecl *D = DS->getDecl(); D; D = D->getNextDeclarator()) {
524      VarDecl *VD = dyn_cast<VarDecl>(D);
525      if (VD && VD->isBlockVarDecl() && !VD->hasLocalStorage())
526        VD = 0;
527      if (VD == 0)
528        Diag(dyn_cast<ScopedDecl>(D)->getLocation(),
529             diag::err_non_variable_decl_in_for);
530      // FIXME: mark decl erroneous!
531    }
532  }
533  if (Second) {
534    DefaultFunctionArrayConversion(Second);
535    QualType SecondType = Second->getType();
536
537    if (!SecondType->isScalarType()) // C99 6.8.5p2
538      return Diag(ForLoc, diag::err_typecheck_statement_requires_scalar,
539               SecondType.getAsString(), Second->getSourceRange());
540  }
541  return new ForStmt(First, Second, Third, Body, ForLoc);
542}
543
544Action::StmtResult
545Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
546                                 SourceLocation LParenLoc,
547                                 StmtTy *first, ExprTy *second,
548                                 SourceLocation RParenLoc, StmtTy *body) {
549  Stmt *First  = static_cast<Stmt*>(first);
550  Expr *Second = static_cast<Expr*>(second);
551  Stmt *Body  = static_cast<Stmt*>(body);
552  if (First) {
553    QualType FirstType;
554    if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) {
555      FirstType = cast<ValueDecl>(DS->getDecl())->getType();
556      // C99 6.8.5p3: The declaration part of a 'for' statement shall only declare
557      // identifiers for objects having storage class 'auto' or 'register'.
558      ScopedDecl *D = DS->getDecl();
559      VarDecl *VD = cast<VarDecl>(D);
560      if (VD->isBlockVarDecl() && !VD->hasLocalStorage())
561        return Diag(VD->getLocation(), diag::err_non_variable_decl_in_for);
562      if (D->getNextDeclarator())
563        return Diag(D->getLocation(), diag::err_toomany_element_decls);
564    } else
565      FirstType = static_cast<Expr*>(first)->getType();
566    if (!isObjCObjectPointerType(FirstType))
567        Diag(ForLoc, diag::err_selector_element_type,
568             FirstType.getAsString(), First->getSourceRange());
569  }
570  if (Second) {
571    DefaultFunctionArrayConversion(Second);
572    QualType SecondType = Second->getType();
573    if (!isObjCObjectPointerType(SecondType))
574      Diag(ForLoc, diag::err_collection_expr_type,
575           SecondType.getAsString(), Second->getSourceRange());
576  }
577  return new ObjCForCollectionStmt(First, Second, Body, ForLoc, RParenLoc);
578}
579
580Action::StmtResult
581Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc,
582                    IdentifierInfo *LabelII) {
583  // Look up the record for this label identifier.
584  LabelStmt *&LabelDecl = LabelMap[LabelII];
585
586  // If we haven't seen this label yet, create a forward reference.
587  if (LabelDecl == 0)
588    LabelDecl = new LabelStmt(LabelLoc, LabelII, 0);
589
590  return new GotoStmt(LabelDecl, GotoLoc, LabelLoc);
591}
592
593Action::StmtResult
594Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc,SourceLocation StarLoc,
595                            ExprTy *DestExp) {
596  // FIXME: Verify that the operand is convertible to void*.
597
598  return new IndirectGotoStmt((Expr*)DestExp);
599}
600
601Action::StmtResult
602Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
603  Scope *S = CurScope->getContinueParent();
604  if (!S) {
605    // C99 6.8.6.2p1: A break shall appear only in or as a loop body.
606    Diag(ContinueLoc, diag::err_continue_not_in_loop);
607    return true;
608  }
609
610  return new ContinueStmt(ContinueLoc);
611}
612
613Action::StmtResult
614Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
615  Scope *S = CurScope->getBreakParent();
616  if (!S) {
617    // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
618    Diag(BreakLoc, diag::err_break_not_in_loop_or_switch);
619    return true;
620  }
621
622  return new BreakStmt(BreakLoc);
623}
624
625
626Action::StmtResult
627Sema::ActOnReturnStmt(SourceLocation ReturnLoc, ExprTy *rex) {
628  Expr *RetValExp = static_cast<Expr *>(rex);
629  QualType FnRetType = CurFunctionDecl ? CurFunctionDecl->getResultType() :
630                                         CurMethodDecl->getResultType();
631
632  if (FnRetType->isVoidType()) {
633    if (RetValExp) // C99 6.8.6.4p1 (ext_ since GCC warns)
634      Diag(ReturnLoc, diag::ext_return_has_expr,
635           (CurFunctionDecl ? CurFunctionDecl->getIdentifier()->getName() :
636            CurMethodDecl->getSelector().getName()),
637           RetValExp->getSourceRange());
638    return new ReturnStmt(ReturnLoc, RetValExp);
639  } else {
640    if (!RetValExp) {
641      const char *funcName = CurFunctionDecl ?
642                               CurFunctionDecl->getIdentifier()->getName() :
643                               CurMethodDecl->getSelector().getName().c_str();
644      if (getLangOptions().C99)  // C99 6.8.6.4p1 (ext_ since GCC warns)
645        Diag(ReturnLoc, diag::ext_return_missing_expr, funcName);
646      else  // C90 6.6.6.4p4
647        Diag(ReturnLoc, diag::warn_return_missing_expr, funcName);
648      return new ReturnStmt(ReturnLoc, (Expr*)0);
649    }
650  }
651  // we have a non-void function with an expression, continue checking
652  QualType RetValType = RetValExp->getType();
653
654  // C99 6.8.6.4p3(136): The return statement is not an assignment. The
655  // overlap restriction of subclause 6.5.16.1 does not apply to the case of
656  // function return.
657  AssignConvertType ConvTy = CheckSingleAssignmentConstraints(FnRetType,
658                                                              RetValExp);
659  if (DiagnoseAssignmentResult(ConvTy, ReturnLoc, FnRetType,
660                               RetValType, RetValExp, "returning"))
661    return true;
662
663  if (RetValExp) CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc);
664
665  return new ReturnStmt(ReturnLoc, (Expr*)RetValExp);
666}
667
668Sema::StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc,
669                                    bool IsSimple,
670                                    bool IsVolatile,
671                                    unsigned NumOutputs,
672                                    unsigned NumInputs,
673                                    std::string *Names,
674                                    ExprTy **Constraints,
675                                    ExprTy **Exprs,
676                                    ExprTy *AsmString,
677                                    unsigned NumClobbers,
678                                    ExprTy **Clobbers,
679                                    SourceLocation RParenLoc) {
680  Expr *E = (Expr *)AsmString;
681
682  for (unsigned i = 0; i < NumOutputs; i++) {
683    StringLiteral *Literal = cast<StringLiteral>((Expr *)Constraints[i]);
684    assert(!Literal->isWide() &&
685           "Output constraint strings should not be wide!");
686
687    std::string OutputConstraint(Literal->getStrData(),
688                                 Literal->getByteLength());
689
690    TargetInfo::ConstraintInfo info;
691    if (!Context.Target.validateOutputConstraint(OutputConstraint.c_str(),
692                                                 info)) {
693      // FIXME: We currently leak memory here.
694      Diag(Literal->getLocStart(),
695           diag::err_invalid_output_constraint_in_asm);
696      return true;
697    }
698
699    // Check that the output exprs are valid lvalues.
700    Expr *OutputExpr = (Expr *)Exprs[i];
701    Expr::isLvalueResult Result = OutputExpr->isLvalue();
702    if (Result != Expr::LV_Valid) {
703      ParenExpr *PE = cast<ParenExpr>(OutputExpr);
704
705      Diag(PE->getSubExpr()->getLocStart(),
706           diag::err_invalid_lvalue_in_asm_output,
707           PE->getSubExpr()->getSourceRange());
708
709      // FIXME: We currently leak memory here.
710      return true;
711    }
712  }
713
714  for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
715    StringLiteral *Literal = cast<StringLiteral>((Expr *)Constraints[i]);
716    assert(!Literal->isWide() &&
717           "Output constraint strings should not be wide!");
718
719    std::string InputConstraint(Literal->getStrData(),
720                                Literal->getByteLength());
721
722    TargetInfo::ConstraintInfo info;
723    if (!Context.Target.validateInputConstraint(InputConstraint.c_str(),
724                                                NumOutputs,
725                                                info)) {
726      // FIXME: We currently leak memory here.
727      Diag(Literal->getLocStart(),
728           diag::err_invalid_input_constraint_in_asm);
729      return true;
730    }
731
732    // Check that the input exprs aren't of type void.
733    Expr *InputExpr = (Expr *)Exprs[i];
734    if (InputExpr->getType()->isVoidType()) {
735      ParenExpr *PE = cast<ParenExpr>(InputExpr);
736
737      Diag(PE->getSubExpr()->getLocStart(),
738           diag::err_invalid_type_in_asm_input,
739           PE->getType().getAsString(),
740           PE->getSubExpr()->getSourceRange());
741
742      // FIXME: We currently leak memory here.
743      return true;
744    }
745  }
746
747  // Check that the clobbers are valid.
748  for (unsigned i = 0; i < NumClobbers; i++) {
749    StringLiteral *Literal = cast<StringLiteral>((Expr *)Clobbers[i]);
750    assert(!Literal->isWide() && "Clobber strings should not be wide!");
751
752    llvm::SmallString<16> Clobber(Literal->getStrData(),
753                                  Literal->getStrData() +
754                                  Literal->getByteLength());
755
756    if (!Context.Target.isValidGCCRegisterName(Clobber.c_str())) {
757      Diag(Literal->getLocStart(),
758           diag::err_unknown_register_name_in_asm,
759           Clobber.c_str());
760
761      // FIXME: We currently leak memory here.
762      return true;
763    }
764  }
765
766  return new AsmStmt(AsmLoc,
767                     IsSimple,
768                     IsVolatile,
769                     NumOutputs,
770                     NumInputs,
771                     Names,
772                     reinterpret_cast<StringLiteral**>(Constraints),
773                     reinterpret_cast<Expr**>(Exprs),
774                     cast<StringLiteral>(E),
775                     NumClobbers,
776                     reinterpret_cast<StringLiteral**>(Clobbers),
777                     RParenLoc);
778}
779
780Action::StmtResult
781Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
782                           SourceLocation RParen, StmtTy *Parm,
783                           StmtTy *Body, StmtTy *CatchList) {
784  ObjCAtCatchStmt *CS = new ObjCAtCatchStmt(AtLoc, RParen,
785    static_cast<Stmt*>(Parm), static_cast<Stmt*>(Body),
786    static_cast<Stmt*>(CatchList));
787  return CatchList ? CatchList : CS;
788}
789
790Action::StmtResult
791Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, StmtTy *Body) {
792  ObjCAtFinallyStmt *FS = new ObjCAtFinallyStmt(AtLoc,
793                                                static_cast<Stmt*>(Body));
794  return FS;
795}
796
797Action::StmtResult
798Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc,
799                         StmtTy *Try, StmtTy *Catch, StmtTy *Finally) {
800  ObjCAtTryStmt *TS = new ObjCAtTryStmt(AtLoc, static_cast<Stmt*>(Try),
801                                        static_cast<Stmt*>(Catch),
802                                        static_cast<Stmt*>(Finally));
803  return TS;
804}
805
806Action::StmtResult
807Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, StmtTy *Throw) {
808  ObjCAtThrowStmt *TS = new ObjCAtThrowStmt(AtLoc, static_cast<Stmt*>(Throw));
809  return TS;
810}
811
812Action::StmtResult
813Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprTy *SynchExpr,
814                                  StmtTy *SynchBody) {
815  ObjCAtSynchronizedStmt *SS = new ObjCAtSynchronizedStmt(AtLoc,
816    static_cast<Stmt*>(SynchExpr), static_cast<Stmt*>(SynchBody));
817  return SS;
818}
819
820
821