SemaStmt.cpp revision a5e42a82ce055f29f3733f3a1f10da6cb9877dee
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/Expr.h" 19#include "clang/AST/StmtObjC.h" 20#include "clang/AST/StmtCXX.h" 21#include "clang/Basic/TargetInfo.h" 22#include "llvm/ADT/STLExtras.h" 23#include "llvm/ADT/SmallVector.h" 24using namespace clang; 25 26Sema::OwningStmtResult Sema::ActOnExprStmt(FullExprArg expr) { 27 Expr *E = expr->takeAs<Expr>(); 28 assert(E && "ActOnExprStmt(): missing expression"); 29 30 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 31 // void expression for its side effects. Conversion to void allows any 32 // operand, even incomplete types. 33 34 // Same thing in for stmt first clause (when expr) and third clause. 35 return Owned(static_cast<Stmt*>(E)); 36} 37 38 39Sema::OwningStmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc) { 40 return Owned(new (Context) NullStmt(SemiLoc)); 41} 42 43Sema::OwningStmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, 44 SourceLocation StartLoc, 45 SourceLocation EndLoc) { 46 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 47 48 // If we have an invalid decl, just return an error. 49 if (DG.isNull()) return StmtError(); 50 51 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 52} 53 54void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 55 const Expr *E = dyn_cast_or_null<Expr>(S); 56 if (!E) 57 return; 58 59 // Ignore expressions that have void type. 60 if (E->getType()->isVoidType()) 61 return; 62 63 SourceLocation Loc; 64 SourceRange R1, R2; 65 if (!E->isUnusedResultAWarning(Loc, R1, R2)) 66 return; 67 68 Diag(Loc, diag::warn_unused_expr) << R1 << R2; 69} 70 71Action::OwningStmtResult 72Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 73 MultiStmtArg elts, bool isStmtExpr) { 74 unsigned NumElts = elts.size(); 75 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 76 // If we're in C89 mode, check that we don't have any decls after stmts. If 77 // so, emit an extension diagnostic. 78 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 79 // Note that __extension__ can be around a decl. 80 unsigned i = 0; 81 // Skip over all declarations. 82 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 83 /*empty*/; 84 85 // We found the end of the list or a statement. Scan for another declstmt. 86 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 87 /*empty*/; 88 89 if (i != NumElts) { 90 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 91 Diag(D->getLocation(), diag::ext_mixed_decls_code); 92 } 93 } 94 // Warn about unused expressions in statements. 95 for (unsigned i = 0; i != NumElts; ++i) { 96 // Ignore statements that are last in a statement expression. 97 if (isStmtExpr && i == NumElts - 1) 98 continue; 99 100 DiagnoseUnusedExprResult(Elts[i]); 101 } 102 103 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 104} 105 106Action::OwningStmtResult 107Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprArg lhsval, 108 SourceLocation DotDotDotLoc, ExprArg rhsval, 109 SourceLocation ColonLoc) { 110 assert((lhsval.get() != 0) && "missing expression in case statement"); 111 112 // C99 6.8.4.2p3: The expression shall be an integer constant. 113 // However, GCC allows any evaluatable integer expression. 114 Expr *LHSVal = static_cast<Expr*>(lhsval.get()); 115 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 116 VerifyIntegerConstantExpression(LHSVal)) 117 return StmtError(); 118 119 // GCC extension: The expression shall be an integer constant. 120 121 Expr *RHSVal = static_cast<Expr*>(rhsval.get()); 122 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 123 VerifyIntegerConstantExpression(RHSVal)) { 124 RHSVal = 0; // Recover by just forgetting about it. 125 rhsval = 0; 126 } 127 128 if (getSwitchStack().empty()) { 129 Diag(CaseLoc, diag::err_case_not_in_switch); 130 return StmtError(); 131 } 132 133 // Only now release the smart pointers. 134 lhsval.release(); 135 rhsval.release(); 136 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 137 ColonLoc); 138 getSwitchStack().back()->addSwitchCase(CS); 139 return Owned(CS); 140} 141 142/// ActOnCaseStmtBody - This installs a statement as the body of a case. 143void Sema::ActOnCaseStmtBody(StmtTy *caseStmt, StmtArg subStmt) { 144 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 145 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 146 CS->setSubStmt(SubStmt); 147} 148 149Action::OwningStmtResult 150Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 151 StmtArg subStmt, Scope *CurScope) { 152 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 153 154 if (getSwitchStack().empty()) { 155 Diag(DefaultLoc, diag::err_default_not_in_switch); 156 return Owned(SubStmt); 157 } 158 159 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 160 getSwitchStack().back()->addSwitchCase(DS); 161 return Owned(DS); 162} 163 164Action::OwningStmtResult 165Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II, 166 SourceLocation ColonLoc, StmtArg subStmt) { 167 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 168 // Look up the record for this label identifier. 169 LabelStmt *&LabelDecl = getLabelMap()[II]; 170 171 // If not forward referenced or defined already, just create a new LabelStmt. 172 if (LabelDecl == 0) 173 return Owned(LabelDecl = new (Context) LabelStmt(IdentLoc, II, SubStmt)); 174 175 assert(LabelDecl->getID() == II && "Label mismatch!"); 176 177 // Otherwise, this label was either forward reference or multiply defined. If 178 // multiply defined, reject it now. 179 if (LabelDecl->getSubStmt()) { 180 Diag(IdentLoc, diag::err_redefinition_of_label) << LabelDecl->getID(); 181 Diag(LabelDecl->getIdentLoc(), diag::note_previous_definition); 182 return Owned(SubStmt); 183 } 184 185 // Otherwise, this label was forward declared, and we just found its real 186 // definition. Fill in the forward definition and return it. 187 LabelDecl->setIdentLoc(IdentLoc); 188 LabelDecl->setSubStmt(SubStmt); 189 return Owned(LabelDecl); 190} 191 192Action::OwningStmtResult 193Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, 194 StmtArg ThenVal, SourceLocation ElseLoc, 195 StmtArg ElseVal) { 196 OwningExprResult CondResult(CondVal.release()); 197 198 Expr *condExpr = CondResult.takeAs<Expr>(); 199 200 assert(condExpr && "ActOnIfStmt(): missing expression"); 201 202 if (!condExpr->isTypeDependent()) { 203 DefaultFunctionArrayConversion(condExpr); 204 // Take ownership again until we're past the error checking. 205 CondResult = condExpr; 206 QualType condType = condExpr->getType(); 207 208 if (getLangOptions().CPlusPlus) { 209 if (CheckCXXBooleanCondition(condExpr)) // C++ 6.4p4 210 return StmtError(); 211 } else if (!condType->isScalarType()) // C99 6.8.4.1p1 212 return StmtError(Diag(IfLoc, 213 diag::err_typecheck_statement_requires_scalar) 214 << condType << condExpr->getSourceRange()); 215 } 216 217 Stmt *thenStmt = ThenVal.takeAs<Stmt>(); 218 DiagnoseUnusedExprResult(thenStmt); 219 220 // Warn if the if block has a null body without an else value. 221 // this helps prevent bugs due to typos, such as 222 // if (condition); 223 // do_stuff(); 224 if (!ElseVal.get()) { 225 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 226 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 227 } 228 229 Stmt *elseStmt = ElseVal.takeAs<Stmt>(); 230 DiagnoseUnusedExprResult(elseStmt); 231 232 CondResult.release(); 233 return Owned(new (Context) IfStmt(IfLoc, condExpr, thenStmt, 234 ElseLoc, elseStmt)); 235} 236 237Action::OwningStmtResult 238Sema::ActOnStartOfSwitchStmt(ExprArg cond) { 239 Expr *Cond = cond.takeAs<Expr>(); 240 241 if (getLangOptions().CPlusPlus) { 242 // C++ 6.4.2.p2: 243 // The condition shall be of integral type, enumeration type, or of a class 244 // type for which a single conversion function to integral or enumeration 245 // type exists (12.3). If the condition is of class type, the condition is 246 // converted by calling that conversion function, and the result of the 247 // conversion is used in place of the original condition for the remainder 248 // of this section. Integral promotions are performed. 249 if (!Cond->isTypeDependent()) { 250 QualType Ty = Cond->getType(); 251 252 // FIXME: Handle class types. 253 254 // If the type is wrong a diagnostic will be emitted later at 255 // ActOnFinishSwitchStmt. 256 if (Ty->isIntegralType() || Ty->isEnumeralType()) { 257 // Integral promotions are performed. 258 // FIXME: Integral promotions for C++ are not complete. 259 UsualUnaryConversions(Cond); 260 } 261 } 262 } else { 263 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 264 UsualUnaryConversions(Cond); 265 } 266 267 SwitchStmt *SS = new (Context) SwitchStmt(Cond); 268 getSwitchStack().push_back(SS); 269 return Owned(SS); 270} 271 272/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 273/// the specified width and sign. If an overflow occurs, detect it and emit 274/// the specified diagnostic. 275void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 276 unsigned NewWidth, bool NewSign, 277 SourceLocation Loc, 278 unsigned DiagID) { 279 // Perform a conversion to the promoted condition type if needed. 280 if (NewWidth > Val.getBitWidth()) { 281 // If this is an extension, just do it. 282 llvm::APSInt OldVal(Val); 283 Val.extend(NewWidth); 284 285 // If the input was signed and negative and the output is unsigned, 286 // warn. 287 if (!NewSign && OldVal.isSigned() && OldVal.isNegative()) 288 Diag(Loc, DiagID) << OldVal.toString(10) << Val.toString(10); 289 290 Val.setIsSigned(NewSign); 291 } else if (NewWidth < Val.getBitWidth()) { 292 // If this is a truncation, check for overflow. 293 llvm::APSInt ConvVal(Val); 294 ConvVal.trunc(NewWidth); 295 ConvVal.setIsSigned(NewSign); 296 ConvVal.extend(Val.getBitWidth()); 297 ConvVal.setIsSigned(Val.isSigned()); 298 if (ConvVal != Val) 299 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 300 301 // Regardless of whether a diagnostic was emitted, really do the 302 // truncation. 303 Val.trunc(NewWidth); 304 Val.setIsSigned(NewSign); 305 } else if (NewSign != Val.isSigned()) { 306 // Convert the sign to match the sign of the condition. This can cause 307 // overflow as well: unsigned(INTMIN) 308 llvm::APSInt OldVal(Val); 309 Val.setIsSigned(NewSign); 310 311 if (Val.isNegative()) // Sign bit changes meaning. 312 Diag(Loc, DiagID) << OldVal.toString(10) << Val.toString(10); 313 } 314} 315 316namespace { 317 struct CaseCompareFunctor { 318 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 319 const llvm::APSInt &RHS) { 320 return LHS.first < RHS; 321 } 322 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 323 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 324 return LHS.first < RHS.first; 325 } 326 bool operator()(const llvm::APSInt &LHS, 327 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 328 return LHS < RHS.first; 329 } 330 }; 331} 332 333/// CmpCaseVals - Comparison predicate for sorting case values. 334/// 335static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 336 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 337 if (lhs.first < rhs.first) 338 return true; 339 340 if (lhs.first == rhs.first && 341 lhs.second->getCaseLoc().getRawEncoding() 342 < rhs.second->getCaseLoc().getRawEncoding()) 343 return true; 344 return false; 345} 346 347Action::OwningStmtResult 348Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, StmtArg Switch, 349 StmtArg Body) { 350 Stmt *BodyStmt = Body.takeAs<Stmt>(); 351 352 SwitchStmt *SS = getSwitchStack().back(); 353 assert(SS == (SwitchStmt*)Switch.get() && "switch stack missing push/pop!"); 354 355 SS->setBody(BodyStmt, SwitchLoc); 356 getSwitchStack().pop_back(); 357 358 Expr *CondExpr = SS->getCond(); 359 QualType CondType = CondExpr->getType(); 360 361 if (!CondExpr->isTypeDependent() && 362 !CondType->isIntegerType()) { // C99 6.8.4.2p1 363 Diag(SwitchLoc, diag::err_typecheck_statement_requires_integer) 364 << CondType << CondExpr->getSourceRange(); 365 return StmtError(); 366 } 367 368 // Get the bitwidth of the switched-on value before promotions. We must 369 // convert the integer case values to this width before comparison. 370 bool HasDependentValue 371 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 372 unsigned CondWidth 373 = HasDependentValue? 0 374 : static_cast<unsigned>(Context.getTypeSize(CondType)); 375 bool CondIsSigned = CondType->isSignedIntegerType(); 376 377 // Accumulate all of the case values in a vector so that we can sort them 378 // and detect duplicates. This vector contains the APInt for the case after 379 // it has been converted to the condition type. 380 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 381 CaseValsTy CaseVals; 382 383 // Keep track of any GNU case ranges we see. The APSInt is the low value. 384 std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRanges; 385 386 DefaultStmt *TheDefaultStmt = 0; 387 388 bool CaseListIsErroneous = false; 389 390 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 391 SC = SC->getNextSwitchCase()) { 392 393 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 394 if (TheDefaultStmt) { 395 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 396 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 397 398 // FIXME: Remove the default statement from the switch block so that 399 // we'll return a valid AST. This requires recursing down the AST and 400 // finding it, not something we are set up to do right now. For now, 401 // just lop the entire switch stmt out of the AST. 402 CaseListIsErroneous = true; 403 } 404 TheDefaultStmt = DS; 405 406 } else { 407 CaseStmt *CS = cast<CaseStmt>(SC); 408 409 // We already verified that the expression has a i-c-e value (C99 410 // 6.8.4.2p3) - get that value now. 411 Expr *Lo = CS->getLHS(); 412 413 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 414 HasDependentValue = true; 415 break; 416 } 417 418 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 419 420 // Convert the value to the same width/sign as the condition. 421 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 422 CS->getLHS()->getLocStart(), 423 diag::warn_case_value_overflow); 424 425 // If the LHS is not the same type as the condition, insert an implicit 426 // cast. 427 ImpCastExprToType(Lo, CondType); 428 CS->setLHS(Lo); 429 430 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 431 if (CS->getRHS()) { 432 if (CS->getRHS()->isTypeDependent() || 433 CS->getRHS()->isValueDependent()) { 434 HasDependentValue = true; 435 break; 436 } 437 CaseRanges.push_back(std::make_pair(LoVal, CS)); 438 } else 439 CaseVals.push_back(std::make_pair(LoVal, CS)); 440 } 441 } 442 443 if (!HasDependentValue) { 444 // Sort all the scalar case values so we can easily detect duplicates. 445 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 446 447 if (!CaseVals.empty()) { 448 for (unsigned i = 0, e = CaseVals.size()-1; i != e; ++i) { 449 if (CaseVals[i].first == CaseVals[i+1].first) { 450 // If we have a duplicate, report it. 451 Diag(CaseVals[i+1].second->getLHS()->getLocStart(), 452 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 453 Diag(CaseVals[i].second->getLHS()->getLocStart(), 454 diag::note_duplicate_case_prev); 455 // FIXME: We really want to remove the bogus case stmt from the 456 // substmt, but we have no way to do this right now. 457 CaseListIsErroneous = true; 458 } 459 } 460 } 461 462 // Detect duplicate case ranges, which usually don't exist at all in 463 // the first place. 464 if (!CaseRanges.empty()) { 465 // Sort all the case ranges by their low value so we can easily detect 466 // overlaps between ranges. 467 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 468 469 // Scan the ranges, computing the high values and removing empty ranges. 470 std::vector<llvm::APSInt> HiVals; 471 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 472 CaseStmt *CR = CaseRanges[i].second; 473 Expr *Hi = CR->getRHS(); 474 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 475 476 // Convert the value to the same width/sign as the condition. 477 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 478 CR->getRHS()->getLocStart(), 479 diag::warn_case_value_overflow); 480 481 // If the LHS is not the same type as the condition, insert an implicit 482 // cast. 483 ImpCastExprToType(Hi, CondType); 484 CR->setRHS(Hi); 485 486 // If the low value is bigger than the high value, the case is empty. 487 if (CaseRanges[i].first > HiVal) { 488 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 489 << SourceRange(CR->getLHS()->getLocStart(), 490 CR->getRHS()->getLocEnd()); 491 CaseRanges.erase(CaseRanges.begin()+i); 492 --i, --e; 493 continue; 494 } 495 HiVals.push_back(HiVal); 496 } 497 498 // Rescan the ranges, looking for overlap with singleton values and other 499 // ranges. Since the range list is sorted, we only need to compare case 500 // ranges with their neighbors. 501 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 502 llvm::APSInt &CRLo = CaseRanges[i].first; 503 llvm::APSInt &CRHi = HiVals[i]; 504 CaseStmt *CR = CaseRanges[i].second; 505 506 // Check to see whether the case range overlaps with any 507 // singleton cases. 508 CaseStmt *OverlapStmt = 0; 509 llvm::APSInt OverlapVal(32); 510 511 // Find the smallest value >= the lower bound. If I is in the 512 // case range, then we have overlap. 513 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 514 CaseVals.end(), CRLo, 515 CaseCompareFunctor()); 516 if (I != CaseVals.end() && I->first < CRHi) { 517 OverlapVal = I->first; // Found overlap with scalar. 518 OverlapStmt = I->second; 519 } 520 521 // Find the smallest value bigger than the upper bound. 522 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 523 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 524 OverlapVal = (I-1)->first; // Found overlap with scalar. 525 OverlapStmt = (I-1)->second; 526 } 527 528 // Check to see if this case stmt overlaps with the subsequent 529 // case range. 530 if (i && CRLo <= HiVals[i-1]) { 531 OverlapVal = HiVals[i-1]; // Found overlap with range. 532 OverlapStmt = CaseRanges[i-1].second; 533 } 534 535 if (OverlapStmt) { 536 // If we have a duplicate, report it. 537 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 538 << OverlapVal.toString(10); 539 Diag(OverlapStmt->getLHS()->getLocStart(), 540 diag::note_duplicate_case_prev); 541 // FIXME: We really want to remove the bogus case stmt from the 542 // substmt, but we have no way to do this right now. 543 CaseListIsErroneous = true; 544 } 545 } 546 } 547 } 548 549 // FIXME: If the case list was broken is some way, we don't have a good system 550 // to patch it up. Instead, just return the whole substmt as broken. 551 if (CaseListIsErroneous) 552 return StmtError(); 553 554 Switch.release(); 555 return Owned(SS); 556} 557 558Action::OwningStmtResult 559Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, StmtArg Body) { 560 ExprArg CondArg(Cond.release()); 561 Expr *condExpr = CondArg.takeAs<Expr>(); 562 assert(condExpr && "ActOnWhileStmt(): missing expression"); 563 564 if (!condExpr->isTypeDependent()) { 565 DefaultFunctionArrayConversion(condExpr); 566 CondArg = condExpr; 567 QualType condType = condExpr->getType(); 568 569 if (getLangOptions().CPlusPlus) { 570 if (CheckCXXBooleanCondition(condExpr)) // C++ 6.4p4 571 return StmtError(); 572 } else if (!condType->isScalarType()) // C99 6.8.5p2 573 return StmtError(Diag(WhileLoc, 574 diag::err_typecheck_statement_requires_scalar) 575 << condType << condExpr->getSourceRange()); 576 } 577 578 Stmt *bodyStmt = Body.takeAs<Stmt>(); 579 DiagnoseUnusedExprResult(bodyStmt); 580 581 CondArg.release(); 582 return Owned(new (Context) WhileStmt(condExpr, bodyStmt, WhileLoc)); 583} 584 585Action::OwningStmtResult 586Sema::ActOnDoStmt(SourceLocation DoLoc, StmtArg Body, 587 SourceLocation WhileLoc, SourceLocation CondLParen, 588 ExprArg Cond, SourceLocation CondRParen) { 589 Expr *condExpr = Cond.takeAs<Expr>(); 590 assert(condExpr && "ActOnDoStmt(): missing expression"); 591 592 if (!condExpr->isTypeDependent()) { 593 DefaultFunctionArrayConversion(condExpr); 594 Cond = condExpr; 595 QualType condType = condExpr->getType(); 596 597 if (getLangOptions().CPlusPlus) { 598 if (CheckCXXBooleanCondition(condExpr)) // C++ 6.4p4 599 return StmtError(); 600 } else if (!condType->isScalarType()) // C99 6.8.5p2 601 return StmtError(Diag(DoLoc, 602 diag::err_typecheck_statement_requires_scalar) 603 << condType << condExpr->getSourceRange()); 604 } 605 606 Stmt *bodyStmt = Body.takeAs<Stmt>(); 607 DiagnoseUnusedExprResult(bodyStmt); 608 609 Cond.release(); 610 return Owned(new (Context) DoStmt(bodyStmt, condExpr, DoLoc, 611 WhileLoc, CondRParen)); 612} 613 614Action::OwningStmtResult 615Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 616 StmtArg first, ExprArg second, ExprArg third, 617 SourceLocation RParenLoc, StmtArg body) { 618 Stmt *First = static_cast<Stmt*>(first.get()); 619 Expr *Second = static_cast<Expr*>(second.get()); 620 Expr *Third = static_cast<Expr*>(third.get()); 621 Stmt *Body = static_cast<Stmt*>(body.get()); 622 623 if (!getLangOptions().CPlusPlus) { 624 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 625 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 626 // declare identifiers for objects having storage class 'auto' or 627 // 'register'. 628 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 629 DI!=DE; ++DI) { 630 VarDecl *VD = dyn_cast<VarDecl>(*DI); 631 if (VD && VD->isBlockVarDecl() && !VD->hasLocalStorage()) 632 VD = 0; 633 if (VD == 0) 634 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 635 // FIXME: mark decl erroneous! 636 } 637 } 638 } 639 if (Second && !Second->isTypeDependent()) { 640 DefaultFunctionArrayConversion(Second); 641 QualType SecondType = Second->getType(); 642 643 if (getLangOptions().CPlusPlus) { 644 if (CheckCXXBooleanCondition(Second)) // C++ 6.4p4 645 return StmtError(); 646 } else if (!SecondType->isScalarType()) // C99 6.8.5p2 647 return StmtError(Diag(ForLoc, 648 diag::err_typecheck_statement_requires_scalar) 649 << SecondType << Second->getSourceRange()); 650 } 651 652 DiagnoseUnusedExprResult(First); 653 DiagnoseUnusedExprResult(Third); 654 DiagnoseUnusedExprResult(Body); 655 656 first.release(); 657 second.release(); 658 third.release(); 659 body.release(); 660 return Owned(new (Context) ForStmt(First, Second, Third, Body, ForLoc, 661 LParenLoc, RParenLoc)); 662} 663 664Action::OwningStmtResult 665Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 666 SourceLocation LParenLoc, 667 StmtArg first, ExprArg second, 668 SourceLocation RParenLoc, StmtArg body) { 669 Stmt *First = static_cast<Stmt*>(first.get()); 670 Expr *Second = static_cast<Expr*>(second.get()); 671 Stmt *Body = static_cast<Stmt*>(body.get()); 672 if (First) { 673 QualType FirstType; 674 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 675 if (!DS->isSingleDecl()) 676 return StmtError(Diag((*DS->decl_begin())->getLocation(), 677 diag::err_toomany_element_decls)); 678 679 Decl *D = DS->getSingleDecl(); 680 FirstType = cast<ValueDecl>(D)->getType(); 681 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 682 // declare identifiers for objects having storage class 'auto' or 683 // 'register'. 684 VarDecl *VD = cast<VarDecl>(D); 685 if (VD->isBlockVarDecl() && !VD->hasLocalStorage()) 686 return StmtError(Diag(VD->getLocation(), 687 diag::err_non_variable_decl_in_for)); 688 } else { 689 if (cast<Expr>(First)->isLvalue(Context) != Expr::LV_Valid) 690 return StmtError(Diag(First->getLocStart(), 691 diag::err_selector_element_not_lvalue) 692 << First->getSourceRange()); 693 694 FirstType = static_cast<Expr*>(First)->getType(); 695 } 696 if (!FirstType->isObjCObjectPointerType() && 697 !FirstType->isBlockPointerType()) 698 Diag(ForLoc, diag::err_selector_element_type) 699 << FirstType << First->getSourceRange(); 700 } 701 if (Second) { 702 DefaultFunctionArrayConversion(Second); 703 QualType SecondType = Second->getType(); 704 if (!SecondType->isObjCObjectPointerType()) 705 Diag(ForLoc, diag::err_collection_expr_type) 706 << SecondType << Second->getSourceRange(); 707 } 708 first.release(); 709 second.release(); 710 body.release(); 711 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 712 ForLoc, RParenLoc)); 713} 714 715Action::OwningStmtResult 716Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, 717 IdentifierInfo *LabelII) { 718 // If we are in a block, reject all gotos for now. 719 if (CurBlock) 720 return StmtError(Diag(GotoLoc, diag::err_goto_in_block)); 721 722 // Look up the record for this label identifier. 723 LabelStmt *&LabelDecl = getLabelMap()[LabelII]; 724 725 // If we haven't seen this label yet, create a forward reference. 726 if (LabelDecl == 0) 727 LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0); 728 729 return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc)); 730} 731 732Action::OwningStmtResult 733Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 734 ExprArg DestExp) { 735 // Convert operand to void* 736 Expr* E = DestExp.takeAs<Expr>(); 737 if (!E->isTypeDependent()) { 738 QualType ETy = E->getType(); 739 AssignConvertType ConvTy = 740 CheckSingleAssignmentConstraints(Context.VoidPtrTy, E); 741 if (DiagnoseAssignmentResult(ConvTy, StarLoc, Context.VoidPtrTy, ETy, 742 E, "passing")) 743 return StmtError(); 744 } 745 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 746} 747 748Action::OwningStmtResult 749Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 750 Scope *S = CurScope->getContinueParent(); 751 if (!S) { 752 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 753 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 754 } 755 756 return Owned(new (Context) ContinueStmt(ContinueLoc)); 757} 758 759Action::OwningStmtResult 760Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 761 Scope *S = CurScope->getBreakParent(); 762 if (!S) { 763 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 764 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 765 } 766 767 return Owned(new (Context) BreakStmt(BreakLoc)); 768} 769 770/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 771/// 772Action::OwningStmtResult 773Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 774 // If this is the first return we've seen in the block, infer the type of 775 // the block from it. 776 if (CurBlock->ReturnType.isNull()) { 777 if (RetValExp) { 778 // Don't call UsualUnaryConversions(), since we don't want to do 779 // integer promotions here. 780 DefaultFunctionArrayConversion(RetValExp); 781 CurBlock->ReturnType = RetValExp->getType(); 782 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 783 // We have to remove a 'const' added to copied-in variable which was 784 // part of the implementation spec. and not the actual qualifier for 785 // the variable. 786 if (CDRE->isConstQualAdded()) 787 CurBlock->ReturnType.removeConst(); 788 } 789 } else 790 CurBlock->ReturnType = Context.VoidTy; 791 } 792 QualType FnRetType = CurBlock->ReturnType; 793 794 if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) { 795 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 796 << getCurFunctionOrMethodDecl()->getDeclName(); 797 return StmtError(); 798 } 799 800 // Otherwise, verify that this result type matches the previous one. We are 801 // pickier with blocks than for normal functions because we don't have GCC 802 // compatibility to worry about here. 803 if (CurBlock->ReturnType->isVoidType()) { 804 if (RetValExp) { 805 Diag(ReturnLoc, diag::err_return_block_has_expr); 806 RetValExp->Destroy(Context); 807 RetValExp = 0; 808 } 809 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 810 } 811 812 if (!RetValExp) 813 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 814 815 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 816 // we have a non-void block with an expression, continue checking 817 QualType RetValType = RetValExp->getType(); 818 819 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 820 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 821 // function return. 822 823 // In C++ the return statement is handled via a copy initialization. 824 // the C version of which boils down to CheckSingleAssignmentConstraints. 825 // FIXME: Leaks RetValExp. 826 if (PerformCopyInitialization(RetValExp, FnRetType, "returning")) 827 return StmtError(); 828 829 if (RetValExp) CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 830 } 831 832 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 833} 834 835/// IsReturnCopyElidable - Whether returning @p RetExpr from a function that 836/// returns a @p RetType fulfills the criteria for copy elision (C++0x 12.8p15). 837static bool IsReturnCopyElidable(ASTContext &Ctx, QualType RetType, 838 Expr *RetExpr) { 839 QualType ExprType = RetExpr->getType(); 840 // - in a return statement in a function with ... 841 // ... a class return type ... 842 if (!RetType->isRecordType()) 843 return false; 844 // ... the same cv-unqualified type as the function return type ... 845 if (Ctx.getCanonicalType(RetType).getUnqualifiedType() != 846 Ctx.getCanonicalType(ExprType).getUnqualifiedType()) 847 return false; 848 // ... the expression is the name of a non-volatile automatic object ... 849 // We ignore parentheses here. 850 // FIXME: Is this compliant? 851 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens()); 852 if (!DR) 853 return false; 854 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 855 if (!VD) 856 return false; 857 return VD->hasLocalStorage() && !VD->getType()->isReferenceType() 858 && !VD->getType().isVolatileQualified(); 859} 860 861Action::OwningStmtResult 862Sema::ActOnReturnStmt(SourceLocation ReturnLoc, FullExprArg rex) { 863 Expr *RetValExp = rex->takeAs<Expr>(); 864 if (CurBlock) 865 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 866 867 QualType FnRetType; 868 if (const FunctionDecl *FD = getCurFunctionDecl()) { 869 FnRetType = FD->getResultType(); 870 if (FD->hasAttr<NoReturnAttr>()) 871 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 872 << getCurFunctionOrMethodDecl()->getDeclName(); 873 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 874 FnRetType = MD->getResultType(); 875 else // If we don't have a function/method context, bail. 876 return StmtError(); 877 878 if (FnRetType->isVoidType()) { 879 if (RetValExp) {// C99 6.8.6.4p1 (ext_ since GCC warns) 880 unsigned D = diag::ext_return_has_expr; 881 if (RetValExp->getType()->isVoidType()) 882 D = diag::ext_return_has_void_expr; 883 884 // return (some void expression); is legal in C++. 885 if (D != diag::ext_return_has_void_expr || 886 !getLangOptions().CPlusPlus) { 887 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 888 Diag(ReturnLoc, D) 889 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 890 << RetValExp->getSourceRange(); 891 } 892 } 893 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 894 } 895 896 if (!RetValExp && !FnRetType->isDependentType()) { 897 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 898 // C99 6.8.6.4p1 (ext_ since GCC warns) 899 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 900 901 if (FunctionDecl *FD = getCurFunctionDecl()) 902 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 903 else 904 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 905 return Owned(new (Context) ReturnStmt(ReturnLoc, (Expr*)0)); 906 } 907 908 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 909 // we have a non-void function with an expression, continue checking 910 911 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 912 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 913 // function return. 914 915 // C++0x 12.8p15: When certain criteria are met, an implementation is 916 // allowed to omit the copy construction of a class object, [...] 917 // - in a return statement in a function with a class return type, when 918 // the expression is the name of a non-volatile automatic object with 919 // the same cv-unqualified type as the function return type, the copy 920 // operation can be omitted [...] 921 // C++0x 12.8p16: When the criteria for elision of a copy operation are met 922 // and the object to be copied is designated by an lvalue, overload 923 // resolution to select the constructor for the copy is first performed 924 // as if the object were designated by an rvalue. 925 // Note that we only compute Elidable if we're in C++0x, since we don't 926 // care otherwise. 927 bool Elidable = getLangOptions().CPlusPlus0x ? 928 IsReturnCopyElidable(Context, FnRetType, RetValExp) : 929 false; 930 931 // In C++ the return statement is handled via a copy initialization. 932 // the C version of which boils down to CheckSingleAssignmentConstraints. 933 // FIXME: Leaks RetValExp on error. 934 if (PerformCopyInitialization(RetValExp, FnRetType, "returning", Elidable)) 935 return StmtError(); 936 937 if (RetValExp) CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 938 } 939 940 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 941} 942 943/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 944/// ignore "noop" casts in places where an lvalue is required by an inline asm. 945/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 946/// provide a strong guidance to not use it. 947/// 948/// This method checks to see if the argument is an acceptable l-value and 949/// returns false if it is a case we can handle. 950static bool CheckAsmLValue(const Expr *E, Sema &S) { 951 if (E->isLvalue(S.Context) == Expr::LV_Valid) 952 return false; // Cool, this is an lvalue. 953 954 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 955 // are supposed to allow. 956 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 957 if (E != E2 && E2->isLvalue(S.Context) == Expr::LV_Valid) { 958 if (!S.getLangOptions().HeinousExtensions) 959 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 960 << E->getSourceRange(); 961 else 962 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 963 << E->getSourceRange(); 964 // Accept, even if we emitted an error diagnostic. 965 return false; 966 } 967 968 // None of the above, just randomly invalid non-lvalue. 969 return true; 970} 971 972 973Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 974 bool IsSimple, 975 bool IsVolatile, 976 unsigned NumOutputs, 977 unsigned NumInputs, 978 std::string *Names, 979 MultiExprArg constraints, 980 MultiExprArg exprs, 981 ExprArg asmString, 982 MultiExprArg clobbers, 983 SourceLocation RParenLoc) { 984 unsigned NumClobbers = clobbers.size(); 985 StringLiteral **Constraints = 986 reinterpret_cast<StringLiteral**>(constraints.get()); 987 Expr **Exprs = reinterpret_cast<Expr **>(exprs.get()); 988 StringLiteral *AsmString = cast<StringLiteral>((Expr *)asmString.get()); 989 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 990 991 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 992 993 // The parser verifies that there is a string literal here. 994 if (AsmString->isWide()) 995 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 996 << AsmString->getSourceRange()); 997 998 for (unsigned i = 0; i != NumOutputs; i++) { 999 StringLiteral *Literal = Constraints[i]; 1000 if (Literal->isWide()) 1001 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1002 << Literal->getSourceRange()); 1003 1004 TargetInfo::ConstraintInfo Info(Literal->getStrData(), 1005 Literal->getByteLength(), 1006 Names[i]); 1007 if (!Context.Target.validateOutputConstraint(Info)) 1008 return StmtError(Diag(Literal->getLocStart(), 1009 diag::err_asm_invalid_output_constraint) 1010 << Info.getConstraintStr()); 1011 1012 // Check that the output exprs are valid lvalues. 1013 Expr *OutputExpr = Exprs[i]; 1014 if (CheckAsmLValue(OutputExpr, *this)) { 1015 return StmtError(Diag(OutputExpr->getLocStart(), 1016 diag::err_asm_invalid_lvalue_in_output) 1017 << OutputExpr->getSourceRange()); 1018 } 1019 1020 OutputConstraintInfos.push_back(Info); 1021 } 1022 1023 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1024 1025 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1026 StringLiteral *Literal = Constraints[i]; 1027 if (Literal->isWide()) 1028 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1029 << Literal->getSourceRange()); 1030 1031 TargetInfo::ConstraintInfo Info(Literal->getStrData(), 1032 Literal->getByteLength(), 1033 Names[i]); 1034 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1035 NumOutputs, Info)) { 1036 return StmtError(Diag(Literal->getLocStart(), 1037 diag::err_asm_invalid_input_constraint) 1038 << Info.getConstraintStr()); 1039 } 1040 1041 Expr *InputExpr = Exprs[i]; 1042 1043 // Only allow void types for memory constraints. 1044 if (Info.allowsMemory() && !Info.allowsRegister()) { 1045 if (CheckAsmLValue(InputExpr, *this)) 1046 return StmtError(Diag(InputExpr->getLocStart(), 1047 diag::err_asm_invalid_lvalue_in_input) 1048 << Info.getConstraintStr() 1049 << InputExpr->getSourceRange()); 1050 } 1051 1052 if (Info.allowsRegister()) { 1053 if (InputExpr->getType()->isVoidType()) { 1054 return StmtError(Diag(InputExpr->getLocStart(), 1055 diag::err_asm_invalid_type_in_input) 1056 << InputExpr->getType() << Info.getConstraintStr() 1057 << InputExpr->getSourceRange()); 1058 } 1059 } 1060 1061 DefaultFunctionArrayConversion(Exprs[i]); 1062 1063 InputConstraintInfos.push_back(Info); 1064 } 1065 1066 // Check that the clobbers are valid. 1067 for (unsigned i = 0; i != NumClobbers; i++) { 1068 StringLiteral *Literal = Clobbers[i]; 1069 if (Literal->isWide()) 1070 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1071 << Literal->getSourceRange()); 1072 1073 llvm::SmallString<16> Clobber(Literal->getStrData(), 1074 Literal->getStrData() + 1075 Literal->getByteLength()); 1076 1077 if (!Context.Target.isValidGCCRegisterName(Clobber.c_str())) 1078 return StmtError(Diag(Literal->getLocStart(), 1079 diag::err_asm_unknown_register_name) << Clobber.c_str()); 1080 } 1081 1082 constraints.release(); 1083 exprs.release(); 1084 asmString.release(); 1085 clobbers.release(); 1086 AsmStmt *NS = 1087 new (Context) AsmStmt(AsmLoc, IsSimple, IsVolatile, NumOutputs, NumInputs, 1088 Names, Constraints, Exprs, AsmString, NumClobbers, 1089 Clobbers, RParenLoc); 1090 // Validate the asm string, ensuring it makes sense given the operands we 1091 // have. 1092 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1093 unsigned DiagOffs; 1094 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1095 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1096 << AsmString->getSourceRange(); 1097 DeleteStmt(NS); 1098 return StmtError(); 1099 } 1100 1101 // Validate tied input operands for type mismatches. 1102 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1103 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1104 1105 // If this is a tied constraint, verify that the output and input have 1106 // either exactly the same type, or that they are int/ptr operands with the 1107 // same size (int/long, int*/long, are ok etc). 1108 if (!Info.hasTiedOperand()) continue; 1109 1110 unsigned TiedTo = Info.getTiedOperand(); 1111 Expr *OutputExpr = Exprs[TiedTo]; 1112 Expr *InputExpr = Exprs[i+NumOutputs]; 1113 QualType InTy = InputExpr->getType(); 1114 QualType OutTy = OutputExpr->getType(); 1115 if (Context.hasSameType(InTy, OutTy)) 1116 continue; // All types can be tied to themselves. 1117 1118 // Int/ptr operands have some special cases that we allow. 1119 if ((OutTy->isIntegerType() || OutTy->isPointerType()) && 1120 (InTy->isIntegerType() || InTy->isPointerType())) { 1121 1122 // They are ok if they are the same size. Tying void* to int is ok if 1123 // they are the same size, for example. This also allows tying void* to 1124 // int*. 1125 uint64_t OutSize = Context.getTypeSize(OutTy); 1126 uint64_t InSize = Context.getTypeSize(InTy); 1127 if (OutSize == InSize) 1128 continue; 1129 1130 // If the smaller input/output operand is not mentioned in the asm string, 1131 // then we can promote it and the asm string won't notice. Check this 1132 // case now. 1133 bool SmallerValueMentioned = false; 1134 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1135 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1136 if (!Piece.isOperand()) continue; 1137 1138 // If this is a reference to the input and if the input was the smaller 1139 // one, then we have to reject this asm. 1140 if (Piece.getOperandNo() == i+NumOutputs) { 1141 if (InSize < OutSize) { 1142 SmallerValueMentioned = true; 1143 break; 1144 } 1145 } 1146 1147 // If this is a reference to the input and if the input was the smaller 1148 // one, then we have to reject this asm. 1149 if (Piece.getOperandNo() == TiedTo) { 1150 if (InSize > OutSize) { 1151 SmallerValueMentioned = true; 1152 break; 1153 } 1154 } 1155 } 1156 1157 // If the smaller value wasn't mentioned in the asm string, and if the 1158 // output was a register, just extend the shorter one to the size of the 1159 // larger one. 1160 if (!SmallerValueMentioned && 1161 OutputConstraintInfos[TiedTo].allowsRegister()) 1162 continue; 1163 } 1164 1165 Diag(InputExpr->getLocStart(), 1166 diag::err_asm_tying_incompatible_types) 1167 << InTy << OutTy << OutputExpr->getSourceRange() 1168 << InputExpr->getSourceRange(); 1169 DeleteStmt(NS); 1170 return StmtError(); 1171 } 1172 1173 return Owned(NS); 1174} 1175 1176Action::OwningStmtResult 1177Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1178 SourceLocation RParen, DeclPtrTy Parm, 1179 StmtArg Body, StmtArg catchList) { 1180 Stmt *CatchList = catchList.takeAs<Stmt>(); 1181 ParmVarDecl *PVD = cast_or_null<ParmVarDecl>(Parm.getAs<Decl>()); 1182 1183 // PVD == 0 implies @catch(...). 1184 if (PVD) { 1185 // If we already know the decl is invalid, reject it. 1186 if (PVD->isInvalidDecl()) 1187 return StmtError(); 1188 1189 if (!PVD->getType()->isObjCObjectPointerType()) 1190 return StmtError(Diag(PVD->getLocation(), 1191 diag::err_catch_param_not_objc_type)); 1192 if (PVD->getType()->isObjCQualifiedIdType()) 1193 return StmtError(Diag(PVD->getLocation(), 1194 diag::err_illegal_qualifiers_on_catch_parm)); 1195 } 1196 1197 ObjCAtCatchStmt *CS = new (Context) ObjCAtCatchStmt(AtLoc, RParen, 1198 PVD, Body.takeAs<Stmt>(), CatchList); 1199 return Owned(CatchList ? CatchList : CS); 1200} 1201 1202Action::OwningStmtResult 1203Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, StmtArg Body) { 1204 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, 1205 static_cast<Stmt*>(Body.release()))); 1206} 1207 1208Action::OwningStmtResult 1209Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, 1210 StmtArg Try, StmtArg Catch, StmtArg Finally) { 1211 CurFunctionNeedsScopeChecking = true; 1212 return Owned(new (Context) ObjCAtTryStmt(AtLoc, Try.takeAs<Stmt>(), 1213 Catch.takeAs<Stmt>(), 1214 Finally.takeAs<Stmt>())); 1215} 1216 1217Action::OwningStmtResult 1218Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg expr,Scope *CurScope) { 1219 Expr *ThrowExpr = expr.takeAs<Expr>(); 1220 if (!ThrowExpr) { 1221 // @throw without an expression designates a rethrow (which much occur 1222 // in the context of an @catch clause). 1223 Scope *AtCatchParent = CurScope; 1224 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1225 AtCatchParent = AtCatchParent->getParent(); 1226 if (!AtCatchParent) 1227 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1228 } else { 1229 QualType ThrowType = ThrowExpr->getType(); 1230 // Make sure the expression type is an ObjC pointer or "void *". 1231 if (!ThrowType->isObjCObjectPointerType()) { 1232 const PointerType *PT = ThrowType->getAs<PointerType>(); 1233 if (!PT || !PT->getPointeeType()->isVoidType()) 1234 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1235 << ThrowExpr->getType() << ThrowExpr->getSourceRange()); 1236 } 1237 } 1238 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, ThrowExpr)); 1239} 1240 1241Action::OwningStmtResult 1242Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprArg SynchExpr, 1243 StmtArg SynchBody) { 1244 CurFunctionNeedsScopeChecking = true; 1245 1246 // Make sure the expression type is an ObjC pointer or "void *". 1247 Expr *SyncExpr = static_cast<Expr*>(SynchExpr.get()); 1248 if (!SyncExpr->getType()->isObjCObjectPointerType()) { 1249 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1250 if (!PT || !PT->getPointeeType()->isVoidType()) 1251 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1252 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1253 } 1254 1255 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, 1256 SynchExpr.takeAs<Stmt>(), 1257 SynchBody.takeAs<Stmt>())); 1258} 1259 1260/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1261/// and creates a proper catch handler from them. 1262Action::OwningStmtResult 1263Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclPtrTy ExDecl, 1264 StmtArg HandlerBlock) { 1265 // There's nothing to test that ActOnExceptionDecl didn't already test. 1266 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1267 cast_or_null<VarDecl>(ExDecl.getAs<Decl>()), 1268 HandlerBlock.takeAs<Stmt>())); 1269} 1270 1271class TypeWithHandler { 1272 QualType t; 1273 CXXCatchStmt *stmt; 1274public: 1275 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1276 : t(type), stmt(statement) {} 1277 1278 bool operator<(const TypeWithHandler &y) const { 1279 if (t.getTypePtr() < y.t.getTypePtr()) 1280 return true; 1281 else if (t.getTypePtr() > y.t.getTypePtr()) 1282 return false; 1283 else if (t.getCVRQualifiers() < y.t.getCVRQualifiers()) 1284 return true; 1285 else if (t.getCVRQualifiers() < y.t.getCVRQualifiers()) 1286 return false; 1287 else 1288 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1289 } 1290 1291 bool operator==(const TypeWithHandler& other) const { 1292 return t.getTypePtr() == other.t.getTypePtr() 1293 && t.getCVRQualifiers() == other.t.getCVRQualifiers(); 1294 } 1295 1296 QualType getQualType() const { return t; } 1297 CXXCatchStmt *getCatchStmt() const { return stmt; } 1298 SourceLocation getTypeSpecStartLoc() const { 1299 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1300 } 1301}; 1302 1303/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1304/// handlers and creates a try statement from them. 1305Action::OwningStmtResult 1306Sema::ActOnCXXTryBlock(SourceLocation TryLoc, StmtArg TryBlock, 1307 MultiStmtArg RawHandlers) { 1308 unsigned NumHandlers = RawHandlers.size(); 1309 assert(NumHandlers > 0 && 1310 "The parser shouldn't call this if there are no handlers."); 1311 Stmt **Handlers = reinterpret_cast<Stmt**>(RawHandlers.get()); 1312 1313 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1314 1315 for(unsigned i = 0; i < NumHandlers; ++i) { 1316 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1317 if (!Handler->getExceptionDecl()) { 1318 if (i < NumHandlers - 1) 1319 return StmtError(Diag(Handler->getLocStart(), 1320 diag::err_early_catch_all)); 1321 1322 continue; 1323 } 1324 1325 const QualType CaughtType = Handler->getCaughtType(); 1326 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1327 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1328 } 1329 1330 // Detect handlers for the same type as an earlier one. 1331 if (NumHandlers > 1) { 1332 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1333 1334 TypeWithHandler prev = TypesWithHandlers[0]; 1335 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1336 TypeWithHandler curr = TypesWithHandlers[i]; 1337 1338 if (curr == prev) { 1339 Diag(curr.getTypeSpecStartLoc(), 1340 diag::warn_exception_caught_by_earlier_handler) 1341 << curr.getCatchStmt()->getCaughtType().getAsString(); 1342 Diag(prev.getTypeSpecStartLoc(), 1343 diag::note_previous_exception_handler) 1344 << prev.getCatchStmt()->getCaughtType().getAsString(); 1345 } 1346 1347 prev = curr; 1348 } 1349 } 1350 1351 // FIXME: We should detect handlers that cannot catch anything because an 1352 // earlier handler catches a superclass. Need to find a method that is not 1353 // quadratic for this. 1354 // Neither of these are explicitly forbidden, but every compiler detects them 1355 // and warns. 1356 1357 CurFunctionNeedsScopeChecking = true; 1358 RawHandlers.release(); 1359 return Owned(new (Context) CXXTryStmt(TryLoc, 1360 static_cast<Stmt*>(TryBlock.release()), 1361 Handlers, NumHandlers)); 1362} 1363