SemaStmt.cpp revision 3af708ff19e4ae2bf9e40550548361b00e5916bf
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 Diag(ForLoc, diag::err_selector_element_type) 698 << FirstType << First->getSourceRange(); 699 } 700 if (Second) { 701 DefaultFunctionArrayConversion(Second); 702 QualType SecondType = Second->getType(); 703 if (!SecondType->isObjCObjectPointerType()) 704 Diag(ForLoc, diag::err_collection_expr_type) 705 << SecondType << Second->getSourceRange(); 706 } 707 first.release(); 708 second.release(); 709 body.release(); 710 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 711 ForLoc, RParenLoc)); 712} 713 714Action::OwningStmtResult 715Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, 716 IdentifierInfo *LabelII) { 717 // If we are in a block, reject all gotos for now. 718 if (CurBlock) 719 return StmtError(Diag(GotoLoc, diag::err_goto_in_block)); 720 721 // Look up the record for this label identifier. 722 LabelStmt *&LabelDecl = getLabelMap()[LabelII]; 723 724 // If we haven't seen this label yet, create a forward reference. 725 if (LabelDecl == 0) 726 LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0); 727 728 return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc)); 729} 730 731Action::OwningStmtResult 732Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 733 ExprArg DestExp) { 734 // Convert operand to void* 735 Expr* E = DestExp.takeAs<Expr>(); 736 if (!E->isTypeDependent()) { 737 QualType ETy = E->getType(); 738 AssignConvertType ConvTy = 739 CheckSingleAssignmentConstraints(Context.VoidPtrTy, E); 740 if (DiagnoseAssignmentResult(ConvTy, StarLoc, Context.VoidPtrTy, ETy, 741 E, "passing")) 742 return StmtError(); 743 } 744 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 745} 746 747Action::OwningStmtResult 748Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 749 Scope *S = CurScope->getContinueParent(); 750 if (!S) { 751 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 752 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 753 } 754 755 return Owned(new (Context) ContinueStmt(ContinueLoc)); 756} 757 758Action::OwningStmtResult 759Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 760 Scope *S = CurScope->getBreakParent(); 761 if (!S) { 762 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 763 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 764 } 765 766 return Owned(new (Context) BreakStmt(BreakLoc)); 767} 768 769/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 770/// 771Action::OwningStmtResult 772Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 773 // If this is the first return we've seen in the block, infer the type of 774 // the block from it. 775 if (CurBlock->ReturnType.isNull()) { 776 if (RetValExp) { 777 // Don't call UsualUnaryConversions(), since we don't want to do 778 // integer promotions here. 779 DefaultFunctionArrayConversion(RetValExp); 780 CurBlock->ReturnType = RetValExp->getType(); 781 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 782 // We have to remove a 'const' added to copied-in variable which was 783 // part of the implementation spec. and not the actual qualifier for 784 // the variable. 785 if (CDRE->isConstQualAdded()) 786 CurBlock->ReturnType.removeConst(); 787 } 788 } else 789 CurBlock->ReturnType = Context.VoidTy; 790 } 791 QualType FnRetType = CurBlock->ReturnType; 792 793 if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) { 794 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 795 << getCurFunctionOrMethodDecl()->getDeclName(); 796 return StmtError(); 797 } 798 799 // Otherwise, verify that this result type matches the previous one. We are 800 // pickier with blocks than for normal functions because we don't have GCC 801 // compatibility to worry about here. 802 if (CurBlock->ReturnType->isVoidType()) { 803 if (RetValExp) { 804 Diag(ReturnLoc, diag::err_return_block_has_expr); 805 RetValExp->Destroy(Context); 806 RetValExp = 0; 807 } 808 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 809 } 810 811 if (!RetValExp) 812 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 813 814 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 815 // we have a non-void block with an expression, continue checking 816 QualType RetValType = RetValExp->getType(); 817 818 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 819 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 820 // function return. 821 822 // In C++ the return statement is handled via a copy initialization. 823 // the C version of which boils down to CheckSingleAssignmentConstraints. 824 // FIXME: Leaks RetValExp. 825 if (PerformCopyInitialization(RetValExp, FnRetType, "returning")) 826 return StmtError(); 827 828 if (RetValExp) CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 829 } 830 831 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 832} 833 834/// IsReturnCopyElidable - Whether returning @p RetExpr from a function that 835/// returns a @p RetType fulfills the criteria for copy elision (C++0x 12.8p15). 836static bool IsReturnCopyElidable(ASTContext &Ctx, QualType RetType, 837 Expr *RetExpr) { 838 QualType ExprType = RetExpr->getType(); 839 // - in a return statement in a function with ... 840 // ... a class return type ... 841 if (!RetType->isRecordType()) 842 return false; 843 // ... the same cv-unqualified type as the function return type ... 844 if (Ctx.getCanonicalType(RetType).getUnqualifiedType() != 845 Ctx.getCanonicalType(ExprType).getUnqualifiedType()) 846 return false; 847 // ... the expression is the name of a non-volatile automatic object ... 848 // We ignore parentheses here. 849 // FIXME: Is this compliant? 850 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens()); 851 if (!DR) 852 return false; 853 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 854 if (!VD) 855 return false; 856 return VD->hasLocalStorage() && !VD->getType()->isReferenceType() 857 && !VD->getType().isVolatileQualified(); 858} 859 860Action::OwningStmtResult 861Sema::ActOnReturnStmt(SourceLocation ReturnLoc, FullExprArg rex) { 862 Expr *RetValExp = rex->takeAs<Expr>(); 863 if (CurBlock) 864 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 865 866 QualType FnRetType; 867 if (const FunctionDecl *FD = getCurFunctionDecl()) { 868 FnRetType = FD->getResultType(); 869 if (FD->hasAttr<NoReturnAttr>()) 870 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 871 << getCurFunctionOrMethodDecl()->getDeclName(); 872 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 873 FnRetType = MD->getResultType(); 874 else // If we don't have a function/method context, bail. 875 return StmtError(); 876 877 if (FnRetType->isVoidType()) { 878 if (RetValExp) {// C99 6.8.6.4p1 (ext_ since GCC warns) 879 unsigned D = diag::ext_return_has_expr; 880 if (RetValExp->getType()->isVoidType()) 881 D = diag::ext_return_has_void_expr; 882 883 // return (some void expression); is legal in C++. 884 if (D != diag::ext_return_has_void_expr || 885 !getLangOptions().CPlusPlus) { 886 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 887 Diag(ReturnLoc, D) 888 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 889 << RetValExp->getSourceRange(); 890 } 891 } 892 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 893 } 894 895 if (!RetValExp && !FnRetType->isDependentType()) { 896 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 897 // C99 6.8.6.4p1 (ext_ since GCC warns) 898 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 899 900 if (FunctionDecl *FD = getCurFunctionDecl()) 901 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 902 else 903 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 904 return Owned(new (Context) ReturnStmt(ReturnLoc, (Expr*)0)); 905 } 906 907 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 908 // we have a non-void function with an expression, continue checking 909 910 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 911 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 912 // function return. 913 914 // C++0x 12.8p15: When certain criteria are met, an implementation is 915 // allowed to omit the copy construction of a class object, [...] 916 // - in a return statement in a function with a class return type, when 917 // the expression is the name of a non-volatile automatic object with 918 // the same cv-unqualified type as the function return type, the copy 919 // operation can be omitted [...] 920 // C++0x 12.8p16: When the criteria for elision of a copy operation are met 921 // and the object to be copied is designated by an lvalue, overload 922 // resolution to select the constructor for the copy is first performed 923 // as if the object were designated by an rvalue. 924 // Note that we only compute Elidable if we're in C++0x, since we don't 925 // care otherwise. 926 bool Elidable = getLangOptions().CPlusPlus0x ? 927 IsReturnCopyElidable(Context, FnRetType, RetValExp) : 928 false; 929 930 // In C++ the return statement is handled via a copy initialization. 931 // the C version of which boils down to CheckSingleAssignmentConstraints. 932 // FIXME: Leaks RetValExp on error. 933 if (PerformCopyInitialization(RetValExp, FnRetType, "returning", Elidable)) 934 return StmtError(); 935 936 if (RetValExp) CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 937 } 938 939 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 940} 941 942/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 943/// ignore "noop" casts in places where an lvalue is required by an inline asm. 944/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 945/// provide a strong guidance to not use it. 946/// 947/// This method checks to see if the argument is an acceptable l-value and 948/// returns false if it is a case we can handle. 949static bool CheckAsmLValue(const Expr *E, Sema &S) { 950 if (E->isLvalue(S.Context) == Expr::LV_Valid) 951 return false; // Cool, this is an lvalue. 952 953 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 954 // are supposed to allow. 955 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 956 if (E != E2 && E2->isLvalue(S.Context) == Expr::LV_Valid) { 957 if (!S.getLangOptions().HeinousExtensions) 958 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 959 << E->getSourceRange(); 960 else 961 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 962 << E->getSourceRange(); 963 // Accept, even if we emitted an error diagnostic. 964 return false; 965 } 966 967 // None of the above, just randomly invalid non-lvalue. 968 return true; 969} 970 971 972Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 973 bool IsSimple, 974 bool IsVolatile, 975 unsigned NumOutputs, 976 unsigned NumInputs, 977 std::string *Names, 978 MultiExprArg constraints, 979 MultiExprArg exprs, 980 ExprArg asmString, 981 MultiExprArg clobbers, 982 SourceLocation RParenLoc) { 983 unsigned NumClobbers = clobbers.size(); 984 StringLiteral **Constraints = 985 reinterpret_cast<StringLiteral**>(constraints.get()); 986 Expr **Exprs = reinterpret_cast<Expr **>(exprs.get()); 987 StringLiteral *AsmString = cast<StringLiteral>((Expr *)asmString.get()); 988 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 989 990 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 991 992 // The parser verifies that there is a string literal here. 993 if (AsmString->isWide()) 994 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 995 << AsmString->getSourceRange()); 996 997 for (unsigned i = 0; i != NumOutputs; i++) { 998 StringLiteral *Literal = Constraints[i]; 999 if (Literal->isWide()) 1000 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1001 << Literal->getSourceRange()); 1002 1003 TargetInfo::ConstraintInfo Info(Literal->getStrData(), 1004 Literal->getByteLength(), 1005 Names[i]); 1006 if (!Context.Target.validateOutputConstraint(Info)) 1007 return StmtError(Diag(Literal->getLocStart(), 1008 diag::err_asm_invalid_output_constraint) 1009 << Info.getConstraintStr()); 1010 1011 // Check that the output exprs are valid lvalues. 1012 Expr *OutputExpr = Exprs[i]; 1013 if (CheckAsmLValue(OutputExpr, *this)) { 1014 return StmtError(Diag(OutputExpr->getLocStart(), 1015 diag::err_asm_invalid_lvalue_in_output) 1016 << OutputExpr->getSourceRange()); 1017 } 1018 1019 OutputConstraintInfos.push_back(Info); 1020 } 1021 1022 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1023 1024 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1025 StringLiteral *Literal = Constraints[i]; 1026 if (Literal->isWide()) 1027 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1028 << Literal->getSourceRange()); 1029 1030 TargetInfo::ConstraintInfo Info(Literal->getStrData(), 1031 Literal->getByteLength(), 1032 Names[i]); 1033 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1034 NumOutputs, Info)) { 1035 return StmtError(Diag(Literal->getLocStart(), 1036 diag::err_asm_invalid_input_constraint) 1037 << Info.getConstraintStr()); 1038 } 1039 1040 Expr *InputExpr = Exprs[i]; 1041 1042 // Only allow void types for memory constraints. 1043 if (Info.allowsMemory() && !Info.allowsRegister()) { 1044 if (CheckAsmLValue(InputExpr, *this)) 1045 return StmtError(Diag(InputExpr->getLocStart(), 1046 diag::err_asm_invalid_lvalue_in_input) 1047 << Info.getConstraintStr() 1048 << InputExpr->getSourceRange()); 1049 } 1050 1051 if (Info.allowsRegister()) { 1052 if (InputExpr->getType()->isVoidType()) { 1053 return StmtError(Diag(InputExpr->getLocStart(), 1054 diag::err_asm_invalid_type_in_input) 1055 << InputExpr->getType() << Info.getConstraintStr() 1056 << InputExpr->getSourceRange()); 1057 } 1058 } 1059 1060 DefaultFunctionArrayConversion(Exprs[i]); 1061 1062 InputConstraintInfos.push_back(Info); 1063 } 1064 1065 // Check that the clobbers are valid. 1066 for (unsigned i = 0; i != NumClobbers; i++) { 1067 StringLiteral *Literal = Clobbers[i]; 1068 if (Literal->isWide()) 1069 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1070 << Literal->getSourceRange()); 1071 1072 llvm::SmallString<16> Clobber(Literal->getStrData(), 1073 Literal->getStrData() + 1074 Literal->getByteLength()); 1075 1076 if (!Context.Target.isValidGCCRegisterName(Clobber.c_str())) 1077 return StmtError(Diag(Literal->getLocStart(), 1078 diag::err_asm_unknown_register_name) << Clobber.c_str()); 1079 } 1080 1081 constraints.release(); 1082 exprs.release(); 1083 asmString.release(); 1084 clobbers.release(); 1085 AsmStmt *NS = 1086 new (Context) AsmStmt(AsmLoc, IsSimple, IsVolatile, NumOutputs, NumInputs, 1087 Names, Constraints, Exprs, AsmString, NumClobbers, 1088 Clobbers, RParenLoc); 1089 // Validate the asm string, ensuring it makes sense given the operands we 1090 // have. 1091 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1092 unsigned DiagOffs; 1093 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1094 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1095 << AsmString->getSourceRange(); 1096 DeleteStmt(NS); 1097 return StmtError(); 1098 } 1099 1100 // Validate tied input operands for type mismatches. 1101 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1102 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1103 1104 // If this is a tied constraint, verify that the output and input have 1105 // either exactly the same type, or that they are int/ptr operands with the 1106 // same size (int/long, int*/long, are ok etc). 1107 if (!Info.hasTiedOperand()) continue; 1108 1109 unsigned TiedTo = Info.getTiedOperand(); 1110 Expr *OutputExpr = Exprs[TiedTo]; 1111 Expr *InputExpr = Exprs[i+NumOutputs]; 1112 QualType InTy = InputExpr->getType(); 1113 QualType OutTy = OutputExpr->getType(); 1114 if (Context.hasSameType(InTy, OutTy)) 1115 continue; // All types can be tied to themselves. 1116 1117 // Int/ptr operands have some special cases that we allow. 1118 if ((OutTy->isIntegerType() || OutTy->isPointerType()) && 1119 (InTy->isIntegerType() || InTy->isPointerType())) { 1120 1121 // They are ok if they are the same size. Tying void* to int is ok if 1122 // they are the same size, for example. This also allows tying void* to 1123 // int*. 1124 uint64_t OutSize = Context.getTypeSize(OutTy); 1125 uint64_t InSize = Context.getTypeSize(InTy); 1126 if (OutSize == InSize) 1127 continue; 1128 1129 // If the smaller input/output operand is not mentioned in the asm string, 1130 // then we can promote it and the asm string won't notice. Check this 1131 // case now. 1132 bool SmallerValueMentioned = false; 1133 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1134 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1135 if (!Piece.isOperand()) continue; 1136 1137 // If this is a reference to the input and if the input was the smaller 1138 // one, then we have to reject this asm. 1139 if (Piece.getOperandNo() == i+NumOutputs) { 1140 if (InSize < OutSize) { 1141 SmallerValueMentioned = true; 1142 break; 1143 } 1144 } 1145 1146 // If this is a reference to the input and if the input was the smaller 1147 // one, then we have to reject this asm. 1148 if (Piece.getOperandNo() == TiedTo) { 1149 if (InSize > OutSize) { 1150 SmallerValueMentioned = true; 1151 break; 1152 } 1153 } 1154 } 1155 1156 // If the smaller value wasn't mentioned in the asm string, and if the 1157 // output was a register, just extend the shorter one to the size of the 1158 // larger one. 1159 if (!SmallerValueMentioned && 1160 OutputConstraintInfos[TiedTo].allowsRegister()) 1161 continue; 1162 } 1163 1164 Diag(InputExpr->getLocStart(), 1165 diag::err_asm_tying_incompatible_types) 1166 << InTy << OutTy << OutputExpr->getSourceRange() 1167 << InputExpr->getSourceRange(); 1168 DeleteStmt(NS); 1169 return StmtError(); 1170 } 1171 1172 return Owned(NS); 1173} 1174 1175Action::OwningStmtResult 1176Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1177 SourceLocation RParen, DeclPtrTy Parm, 1178 StmtArg Body, StmtArg catchList) { 1179 Stmt *CatchList = catchList.takeAs<Stmt>(); 1180 ParmVarDecl *PVD = cast_or_null<ParmVarDecl>(Parm.getAs<Decl>()); 1181 1182 // PVD == 0 implies @catch(...). 1183 if (PVD) { 1184 // If we already know the decl is invalid, reject it. 1185 if (PVD->isInvalidDecl()) 1186 return StmtError(); 1187 1188 if (!PVD->getType()->isObjCObjectPointerType()) 1189 return StmtError(Diag(PVD->getLocation(), 1190 diag::err_catch_param_not_objc_type)); 1191 if (PVD->getType()->isObjCQualifiedIdType()) 1192 return StmtError(Diag(PVD->getLocation(), 1193 diag::err_illegal_qualifiers_on_catch_parm)); 1194 } 1195 1196 ObjCAtCatchStmt *CS = new (Context) ObjCAtCatchStmt(AtLoc, RParen, 1197 PVD, Body.takeAs<Stmt>(), CatchList); 1198 return Owned(CatchList ? CatchList : CS); 1199} 1200 1201Action::OwningStmtResult 1202Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, StmtArg Body) { 1203 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, 1204 static_cast<Stmt*>(Body.release()))); 1205} 1206 1207Action::OwningStmtResult 1208Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, 1209 StmtArg Try, StmtArg Catch, StmtArg Finally) { 1210 CurFunctionNeedsScopeChecking = true; 1211 return Owned(new (Context) ObjCAtTryStmt(AtLoc, Try.takeAs<Stmt>(), 1212 Catch.takeAs<Stmt>(), 1213 Finally.takeAs<Stmt>())); 1214} 1215 1216Action::OwningStmtResult 1217Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg expr,Scope *CurScope) { 1218 Expr *ThrowExpr = expr.takeAs<Expr>(); 1219 if (!ThrowExpr) { 1220 // @throw without an expression designates a rethrow (which much occur 1221 // in the context of an @catch clause). 1222 Scope *AtCatchParent = CurScope; 1223 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1224 AtCatchParent = AtCatchParent->getParent(); 1225 if (!AtCatchParent) 1226 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1227 } else { 1228 QualType ThrowType = ThrowExpr->getType(); 1229 // Make sure the expression type is an ObjC pointer or "void *". 1230 if (!ThrowType->isObjCObjectPointerType()) { 1231 const PointerType *PT = ThrowType->getAs<PointerType>(); 1232 if (!PT || !PT->getPointeeType()->isVoidType()) 1233 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1234 << ThrowExpr->getType() << ThrowExpr->getSourceRange()); 1235 } 1236 } 1237 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, ThrowExpr)); 1238} 1239 1240Action::OwningStmtResult 1241Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprArg SynchExpr, 1242 StmtArg SynchBody) { 1243 CurFunctionNeedsScopeChecking = true; 1244 1245 // Make sure the expression type is an ObjC pointer or "void *". 1246 Expr *SyncExpr = static_cast<Expr*>(SynchExpr.get()); 1247 if (!SyncExpr->getType()->isObjCObjectPointerType()) { 1248 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1249 if (!PT || !PT->getPointeeType()->isVoidType()) 1250 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1251 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1252 } 1253 1254 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, 1255 SynchExpr.takeAs<Stmt>(), 1256 SynchBody.takeAs<Stmt>())); 1257} 1258 1259/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1260/// and creates a proper catch handler from them. 1261Action::OwningStmtResult 1262Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclPtrTy ExDecl, 1263 StmtArg HandlerBlock) { 1264 // There's nothing to test that ActOnExceptionDecl didn't already test. 1265 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1266 cast_or_null<VarDecl>(ExDecl.getAs<Decl>()), 1267 HandlerBlock.takeAs<Stmt>())); 1268} 1269 1270class TypeWithHandler { 1271 QualType t; 1272 CXXCatchStmt *stmt; 1273public: 1274 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1275 : t(type), stmt(statement) {} 1276 1277 bool operator<(const TypeWithHandler &y) const { 1278 if (t.getTypePtr() < y.t.getTypePtr()) 1279 return true; 1280 else if (t.getTypePtr() > y.t.getTypePtr()) 1281 return false; 1282 else if (t.getCVRQualifiers() < y.t.getCVRQualifiers()) 1283 return true; 1284 else if (t.getCVRQualifiers() < y.t.getCVRQualifiers()) 1285 return false; 1286 else 1287 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1288 } 1289 1290 bool operator==(const TypeWithHandler& other) const { 1291 return t.getTypePtr() == other.t.getTypePtr() 1292 && t.getCVRQualifiers() == other.t.getCVRQualifiers(); 1293 } 1294 1295 QualType getQualType() const { return t; } 1296 CXXCatchStmt *getCatchStmt() const { return stmt; } 1297 SourceLocation getTypeSpecStartLoc() const { 1298 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1299 } 1300}; 1301 1302/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1303/// handlers and creates a try statement from them. 1304Action::OwningStmtResult 1305Sema::ActOnCXXTryBlock(SourceLocation TryLoc, StmtArg TryBlock, 1306 MultiStmtArg RawHandlers) { 1307 unsigned NumHandlers = RawHandlers.size(); 1308 assert(NumHandlers > 0 && 1309 "The parser shouldn't call this if there are no handlers."); 1310 Stmt **Handlers = reinterpret_cast<Stmt**>(RawHandlers.get()); 1311 1312 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1313 1314 for(unsigned i = 0; i < NumHandlers; ++i) { 1315 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1316 if (!Handler->getExceptionDecl()) { 1317 if (i < NumHandlers - 1) 1318 return StmtError(Diag(Handler->getLocStart(), 1319 diag::err_early_catch_all)); 1320 1321 continue; 1322 } 1323 1324 const QualType CaughtType = Handler->getCaughtType(); 1325 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1326 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1327 } 1328 1329 // Detect handlers for the same type as an earlier one. 1330 if (NumHandlers > 1) { 1331 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1332 1333 TypeWithHandler prev = TypesWithHandlers[0]; 1334 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1335 TypeWithHandler curr = TypesWithHandlers[i]; 1336 1337 if (curr == prev) { 1338 Diag(curr.getTypeSpecStartLoc(), 1339 diag::warn_exception_caught_by_earlier_handler) 1340 << curr.getCatchStmt()->getCaughtType().getAsString(); 1341 Diag(prev.getTypeSpecStartLoc(), 1342 diag::note_previous_exception_handler) 1343 << prev.getCatchStmt()->getCaughtType().getAsString(); 1344 } 1345 1346 prev = curr; 1347 } 1348 } 1349 1350 // FIXME: We should detect handlers that cannot catch anything because an 1351 // earlier handler catches a superclass. Need to find a method that is not 1352 // quadratic for this. 1353 // Neither of these are explicitly forbidden, but every compiler detects them 1354 // and warns. 1355 1356 CurFunctionNeedsScopeChecking = true; 1357 RawHandlers.release(); 1358 return Owned(new (Context) CXXTryStmt(TryLoc, 1359 static_cast<Stmt*>(TryBlock.release()), 1360 Handlers, NumHandlers)); 1361} 1362