SemaStmt.cpp revision 16b10378a93e8644008289fd86c1caf737d1395c
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/ExprObjC.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 if (E->getType()->isObjCInterfaceType()) { 30 if (LangOpts.ObjCNonFragileABI) 31 Diag(E->getLocEnd(), diag::err_indirection_requires_nonfragile_object) 32 << E->getType(); 33 else 34 Diag(E->getLocEnd(), diag::err_direct_interface_unsupported) 35 << E->getType(); 36 return StmtError(); 37 } 38 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 39 // void expression for its side effects. Conversion to void allows any 40 // operand, even incomplete types. 41 42 // Same thing in for stmt first clause (when expr) and third clause. 43 return Owned(static_cast<Stmt*>(E)); 44} 45 46 47Sema::OwningStmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc) { 48 return Owned(new (Context) NullStmt(SemiLoc)); 49} 50 51Sema::OwningStmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, 52 SourceLocation StartLoc, 53 SourceLocation EndLoc) { 54 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 55 56 // If we have an invalid decl, just return an error. 57 if (DG.isNull()) return StmtError(); 58 59 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 60} 61 62void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 63 const Expr *E = dyn_cast_or_null<Expr>(S); 64 if (!E) 65 return; 66 67 // Ignore expressions that have void type. 68 if (E->getType()->isVoidType()) 69 return; 70 71 SourceLocation Loc; 72 SourceRange R1, R2; 73 if (!E->isUnusedResultAWarning(Loc, R1, R2)) 74 return; 75 76 // Okay, we have an unused result. Depending on what the base expression is, 77 // we might want to make a more specific diagnostic. Check for one of these 78 // cases now. 79 unsigned DiagID = diag::warn_unused_expr; 80 E = E->IgnoreParens(); 81 if (isa<ObjCImplicitSetterGetterRefExpr>(E)) 82 DiagID = diag::warn_unused_property_expr; 83 84 Diag(Loc, DiagID) << R1 << R2; 85} 86 87Action::OwningStmtResult 88Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 89 MultiStmtArg elts, bool isStmtExpr) { 90 unsigned NumElts = elts.size(); 91 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 92 // If we're in C89 mode, check that we don't have any decls after stmts. If 93 // so, emit an extension diagnostic. 94 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 95 // Note that __extension__ can be around a decl. 96 unsigned i = 0; 97 // Skip over all declarations. 98 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 99 /*empty*/; 100 101 // We found the end of the list or a statement. Scan for another declstmt. 102 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 103 /*empty*/; 104 105 if (i != NumElts) { 106 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 107 Diag(D->getLocation(), diag::ext_mixed_decls_code); 108 } 109 } 110 // Warn about unused expressions in statements. 111 for (unsigned i = 0; i != NumElts; ++i) { 112 // Ignore statements that are last in a statement expression. 113 if (isStmtExpr && i == NumElts - 1) 114 continue; 115 116 DiagnoseUnusedExprResult(Elts[i]); 117 } 118 119 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 120} 121 122Action::OwningStmtResult 123Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprArg lhsval, 124 SourceLocation DotDotDotLoc, ExprArg rhsval, 125 SourceLocation ColonLoc) { 126 assert((lhsval.get() != 0) && "missing expression in case statement"); 127 128 // C99 6.8.4.2p3: The expression shall be an integer constant. 129 // However, GCC allows any evaluatable integer expression. 130 Expr *LHSVal = static_cast<Expr*>(lhsval.get()); 131 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 132 VerifyIntegerConstantExpression(LHSVal)) 133 return StmtError(); 134 135 // GCC extension: The expression shall be an integer constant. 136 137 Expr *RHSVal = static_cast<Expr*>(rhsval.get()); 138 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 139 VerifyIntegerConstantExpression(RHSVal)) { 140 RHSVal = 0; // Recover by just forgetting about it. 141 rhsval = 0; 142 } 143 144 if (getSwitchStack().empty()) { 145 Diag(CaseLoc, diag::err_case_not_in_switch); 146 return StmtError(); 147 } 148 149 // Only now release the smart pointers. 150 lhsval.release(); 151 rhsval.release(); 152 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 153 ColonLoc); 154 getSwitchStack().back()->addSwitchCase(CS); 155 return Owned(CS); 156} 157 158/// ActOnCaseStmtBody - This installs a statement as the body of a case. 159void Sema::ActOnCaseStmtBody(StmtTy *caseStmt, StmtArg subStmt) { 160 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 161 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 162 CS->setSubStmt(SubStmt); 163} 164 165Action::OwningStmtResult 166Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 167 StmtArg subStmt, Scope *CurScope) { 168 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 169 170 if (getSwitchStack().empty()) { 171 Diag(DefaultLoc, diag::err_default_not_in_switch); 172 return Owned(SubStmt); 173 } 174 175 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 176 getSwitchStack().back()->addSwitchCase(DS); 177 return Owned(DS); 178} 179 180Action::OwningStmtResult 181Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II, 182 SourceLocation ColonLoc, StmtArg subStmt) { 183 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 184 // Look up the record for this label identifier. 185 LabelStmt *&LabelDecl = getLabelMap()[II]; 186 187 // If not forward referenced or defined already, just create a new LabelStmt. 188 if (LabelDecl == 0) 189 return Owned(LabelDecl = new (Context) LabelStmt(IdentLoc, II, SubStmt)); 190 191 assert(LabelDecl->getID() == II && "Label mismatch!"); 192 193 // Otherwise, this label was either forward reference or multiply defined. If 194 // multiply defined, reject it now. 195 if (LabelDecl->getSubStmt()) { 196 Diag(IdentLoc, diag::err_redefinition_of_label) << LabelDecl->getID(); 197 Diag(LabelDecl->getIdentLoc(), diag::note_previous_definition); 198 return Owned(SubStmt); 199 } 200 201 // Otherwise, this label was forward declared, and we just found its real 202 // definition. Fill in the forward definition and return it. 203 LabelDecl->setIdentLoc(IdentLoc); 204 LabelDecl->setSubStmt(SubStmt); 205 return Owned(LabelDecl); 206} 207 208Action::OwningStmtResult 209Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, 210 StmtArg ThenVal, SourceLocation ElseLoc, 211 StmtArg ElseVal) { 212 OwningExprResult CondResult(CondVal.release()); 213 214 Expr *condExpr = CondResult.takeAs<Expr>(); 215 216 assert(condExpr && "ActOnIfStmt(): missing expression"); 217 218 if (!condExpr->isTypeDependent()) { 219 DefaultFunctionArrayConversion(condExpr); 220 // Take ownership again until we're past the error checking. 221 CondResult = condExpr; 222 QualType condType = condExpr->getType(); 223 224 if (getLangOptions().CPlusPlus) { 225 if (CheckCXXBooleanCondition(condExpr)) // C++ 6.4p4 226 return StmtError(); 227 } else if (!condType->isScalarType()) // C99 6.8.4.1p1 228 return StmtError(Diag(IfLoc, 229 diag::err_typecheck_statement_requires_scalar) 230 << condType << condExpr->getSourceRange()); 231 } 232 233 Stmt *thenStmt = ThenVal.takeAs<Stmt>(); 234 DiagnoseUnusedExprResult(thenStmt); 235 236 // Warn if the if block has a null body without an else value. 237 // this helps prevent bugs due to typos, such as 238 // if (condition); 239 // do_stuff(); 240 if (!ElseVal.get()) { 241 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 242 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 243 } 244 245 Stmt *elseStmt = ElseVal.takeAs<Stmt>(); 246 DiagnoseUnusedExprResult(elseStmt); 247 248 CondResult.release(); 249 return Owned(new (Context) IfStmt(IfLoc, condExpr, thenStmt, 250 ElseLoc, elseStmt)); 251} 252 253Action::OwningStmtResult 254Sema::ActOnStartOfSwitchStmt(ExprArg cond) { 255 Expr *Cond = cond.takeAs<Expr>(); 256 257 if (getLangOptions().CPlusPlus) { 258 // C++ 6.4.2.p2: 259 // The condition shall be of integral type, enumeration type, or of a class 260 // type for which a single conversion function to integral or enumeration 261 // type exists (12.3). If the condition is of class type, the condition is 262 // converted by calling that conversion function, and the result of the 263 // conversion is used in place of the original condition for the remainder 264 // of this section. Integral promotions are performed. 265 if (!Cond->isTypeDependent()) { 266 QualType Ty = Cond->getType(); 267 268 // FIXME: Handle class types. 269 270 // If the type is wrong a diagnostic will be emitted later at 271 // ActOnFinishSwitchStmt. 272 if (Ty->isIntegralType() || Ty->isEnumeralType()) { 273 // Integral promotions are performed. 274 // FIXME: Integral promotions for C++ are not complete. 275 UsualUnaryConversions(Cond); 276 } 277 } 278 } else { 279 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 280 UsualUnaryConversions(Cond); 281 } 282 283 SwitchStmt *SS = new (Context) SwitchStmt(Cond); 284 getSwitchStack().push_back(SS); 285 return Owned(SS); 286} 287 288/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 289/// the specified width and sign. If an overflow occurs, detect it and emit 290/// the specified diagnostic. 291void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 292 unsigned NewWidth, bool NewSign, 293 SourceLocation Loc, 294 unsigned DiagID) { 295 // Perform a conversion to the promoted condition type if needed. 296 if (NewWidth > Val.getBitWidth()) { 297 // If this is an extension, just do it. 298 llvm::APSInt OldVal(Val); 299 Val.extend(NewWidth); 300 301 // If the input was signed and negative and the output is unsigned, 302 // warn. 303 if (!NewSign && OldVal.isSigned() && OldVal.isNegative()) 304 Diag(Loc, DiagID) << OldVal.toString(10) << Val.toString(10); 305 306 Val.setIsSigned(NewSign); 307 } else if (NewWidth < Val.getBitWidth()) { 308 // If this is a truncation, check for overflow. 309 llvm::APSInt ConvVal(Val); 310 ConvVal.trunc(NewWidth); 311 ConvVal.setIsSigned(NewSign); 312 ConvVal.extend(Val.getBitWidth()); 313 ConvVal.setIsSigned(Val.isSigned()); 314 if (ConvVal != Val) 315 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 316 317 // Regardless of whether a diagnostic was emitted, really do the 318 // truncation. 319 Val.trunc(NewWidth); 320 Val.setIsSigned(NewSign); 321 } else if (NewSign != Val.isSigned()) { 322 // Convert the sign to match the sign of the condition. This can cause 323 // overflow as well: unsigned(INTMIN) 324 llvm::APSInt OldVal(Val); 325 Val.setIsSigned(NewSign); 326 327 if (Val.isNegative()) // Sign bit changes meaning. 328 Diag(Loc, DiagID) << OldVal.toString(10) << Val.toString(10); 329 } 330} 331 332namespace { 333 struct CaseCompareFunctor { 334 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 335 const llvm::APSInt &RHS) { 336 return LHS.first < RHS; 337 } 338 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 339 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 340 return LHS.first < RHS.first; 341 } 342 bool operator()(const llvm::APSInt &LHS, 343 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 344 return LHS < RHS.first; 345 } 346 }; 347} 348 349/// CmpCaseVals - Comparison predicate for sorting case values. 350/// 351static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 352 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 353 if (lhs.first < rhs.first) 354 return true; 355 356 if (lhs.first == rhs.first && 357 lhs.second->getCaseLoc().getRawEncoding() 358 < rhs.second->getCaseLoc().getRawEncoding()) 359 return true; 360 return false; 361} 362 363Action::OwningStmtResult 364Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, StmtArg Switch, 365 StmtArg Body) { 366 Stmt *BodyStmt = Body.takeAs<Stmt>(); 367 368 SwitchStmt *SS = getSwitchStack().back(); 369 assert(SS == (SwitchStmt*)Switch.get() && "switch stack missing push/pop!"); 370 371 SS->setBody(BodyStmt, SwitchLoc); 372 getSwitchStack().pop_back(); 373 374 Expr *CondExpr = SS->getCond(); 375 QualType CondType = CondExpr->getType(); 376 377 if (!CondExpr->isTypeDependent() && 378 !CondType->isIntegerType()) { // C99 6.8.4.2p1 379 Diag(SwitchLoc, diag::err_typecheck_statement_requires_integer) 380 << CondType << CondExpr->getSourceRange(); 381 return StmtError(); 382 } 383 384 // Get the bitwidth of the switched-on value before promotions. We must 385 // convert the integer case values to this width before comparison. 386 bool HasDependentValue 387 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 388 unsigned CondWidth 389 = HasDependentValue? 0 390 : static_cast<unsigned>(Context.getTypeSize(CondType)); 391 bool CondIsSigned = CondType->isSignedIntegerType(); 392 393 // Accumulate all of the case values in a vector so that we can sort them 394 // and detect duplicates. This vector contains the APInt for the case after 395 // it has been converted to the condition type. 396 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 397 CaseValsTy CaseVals; 398 399 // Keep track of any GNU case ranges we see. The APSInt is the low value. 400 std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRanges; 401 402 DefaultStmt *TheDefaultStmt = 0; 403 404 bool CaseListIsErroneous = false; 405 406 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 407 SC = SC->getNextSwitchCase()) { 408 409 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 410 if (TheDefaultStmt) { 411 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 412 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 413 414 // FIXME: Remove the default statement from the switch block so that 415 // we'll return a valid AST. This requires recursing down the AST and 416 // finding it, not something we are set up to do right now. For now, 417 // just lop the entire switch stmt out of the AST. 418 CaseListIsErroneous = true; 419 } 420 TheDefaultStmt = DS; 421 422 } else { 423 CaseStmt *CS = cast<CaseStmt>(SC); 424 425 // We already verified that the expression has a i-c-e value (C99 426 // 6.8.4.2p3) - get that value now. 427 Expr *Lo = CS->getLHS(); 428 429 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 430 HasDependentValue = true; 431 break; 432 } 433 434 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 435 436 // Convert the value to the same width/sign as the condition. 437 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 438 CS->getLHS()->getLocStart(), 439 diag::warn_case_value_overflow); 440 441 // If the LHS is not the same type as the condition, insert an implicit 442 // cast. 443 ImpCastExprToType(Lo, CondType); 444 CS->setLHS(Lo); 445 446 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 447 if (CS->getRHS()) { 448 if (CS->getRHS()->isTypeDependent() || 449 CS->getRHS()->isValueDependent()) { 450 HasDependentValue = true; 451 break; 452 } 453 CaseRanges.push_back(std::make_pair(LoVal, CS)); 454 } else 455 CaseVals.push_back(std::make_pair(LoVal, CS)); 456 } 457 } 458 459 if (!HasDependentValue) { 460 // Sort all the scalar case values so we can easily detect duplicates. 461 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 462 463 if (!CaseVals.empty()) { 464 for (unsigned i = 0, e = CaseVals.size()-1; i != e; ++i) { 465 if (CaseVals[i].first == CaseVals[i+1].first) { 466 // If we have a duplicate, report it. 467 Diag(CaseVals[i+1].second->getLHS()->getLocStart(), 468 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 469 Diag(CaseVals[i].second->getLHS()->getLocStart(), 470 diag::note_duplicate_case_prev); 471 // FIXME: We really want to remove the bogus case stmt from the 472 // substmt, but we have no way to do this right now. 473 CaseListIsErroneous = true; 474 } 475 } 476 } 477 478 // Detect duplicate case ranges, which usually don't exist at all in 479 // the first place. 480 if (!CaseRanges.empty()) { 481 // Sort all the case ranges by their low value so we can easily detect 482 // overlaps between ranges. 483 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 484 485 // Scan the ranges, computing the high values and removing empty ranges. 486 std::vector<llvm::APSInt> HiVals; 487 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 488 CaseStmt *CR = CaseRanges[i].second; 489 Expr *Hi = CR->getRHS(); 490 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 491 492 // Convert the value to the same width/sign as the condition. 493 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 494 CR->getRHS()->getLocStart(), 495 diag::warn_case_value_overflow); 496 497 // If the LHS is not the same type as the condition, insert an implicit 498 // cast. 499 ImpCastExprToType(Hi, CondType); 500 CR->setRHS(Hi); 501 502 // If the low value is bigger than the high value, the case is empty. 503 if (CaseRanges[i].first > HiVal) { 504 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 505 << SourceRange(CR->getLHS()->getLocStart(), 506 CR->getRHS()->getLocEnd()); 507 CaseRanges.erase(CaseRanges.begin()+i); 508 --i, --e; 509 continue; 510 } 511 HiVals.push_back(HiVal); 512 } 513 514 // Rescan the ranges, looking for overlap with singleton values and other 515 // ranges. Since the range list is sorted, we only need to compare case 516 // ranges with their neighbors. 517 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 518 llvm::APSInt &CRLo = CaseRanges[i].first; 519 llvm::APSInt &CRHi = HiVals[i]; 520 CaseStmt *CR = CaseRanges[i].second; 521 522 // Check to see whether the case range overlaps with any 523 // singleton cases. 524 CaseStmt *OverlapStmt = 0; 525 llvm::APSInt OverlapVal(32); 526 527 // Find the smallest value >= the lower bound. If I is in the 528 // case range, then we have overlap. 529 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 530 CaseVals.end(), CRLo, 531 CaseCompareFunctor()); 532 if (I != CaseVals.end() && I->first < CRHi) { 533 OverlapVal = I->first; // Found overlap with scalar. 534 OverlapStmt = I->second; 535 } 536 537 // Find the smallest value bigger than the upper bound. 538 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 539 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 540 OverlapVal = (I-1)->first; // Found overlap with scalar. 541 OverlapStmt = (I-1)->second; 542 } 543 544 // Check to see if this case stmt overlaps with the subsequent 545 // case range. 546 if (i && CRLo <= HiVals[i-1]) { 547 OverlapVal = HiVals[i-1]; // Found overlap with range. 548 OverlapStmt = CaseRanges[i-1].second; 549 } 550 551 if (OverlapStmt) { 552 // If we have a duplicate, report it. 553 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 554 << OverlapVal.toString(10); 555 Diag(OverlapStmt->getLHS()->getLocStart(), 556 diag::note_duplicate_case_prev); 557 // FIXME: We really want to remove the bogus case stmt from the 558 // substmt, but we have no way to do this right now. 559 CaseListIsErroneous = true; 560 } 561 } 562 } 563 } 564 565 // FIXME: If the case list was broken is some way, we don't have a good system 566 // to patch it up. Instead, just return the whole substmt as broken. 567 if (CaseListIsErroneous) 568 return StmtError(); 569 570 Switch.release(); 571 return Owned(SS); 572} 573 574Action::OwningStmtResult 575Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, StmtArg Body) { 576 ExprArg CondArg(Cond.release()); 577 Expr *condExpr = CondArg.takeAs<Expr>(); 578 assert(condExpr && "ActOnWhileStmt(): missing expression"); 579 580 if (!condExpr->isTypeDependent()) { 581 DefaultFunctionArrayConversion(condExpr); 582 CondArg = condExpr; 583 QualType condType = condExpr->getType(); 584 585 if (getLangOptions().CPlusPlus) { 586 if (CheckCXXBooleanCondition(condExpr)) // C++ 6.4p4 587 return StmtError(); 588 } else if (!condType->isScalarType()) // C99 6.8.5p2 589 return StmtError(Diag(WhileLoc, 590 diag::err_typecheck_statement_requires_scalar) 591 << condType << condExpr->getSourceRange()); 592 } 593 594 Stmt *bodyStmt = Body.takeAs<Stmt>(); 595 DiagnoseUnusedExprResult(bodyStmt); 596 597 CondArg.release(); 598 return Owned(new (Context) WhileStmt(condExpr, bodyStmt, WhileLoc)); 599} 600 601Action::OwningStmtResult 602Sema::ActOnDoStmt(SourceLocation DoLoc, StmtArg Body, 603 SourceLocation WhileLoc, SourceLocation CondLParen, 604 ExprArg Cond, SourceLocation CondRParen) { 605 Expr *condExpr = Cond.takeAs<Expr>(); 606 assert(condExpr && "ActOnDoStmt(): missing expression"); 607 608 if (!condExpr->isTypeDependent()) { 609 DefaultFunctionArrayConversion(condExpr); 610 Cond = condExpr; 611 QualType condType = condExpr->getType(); 612 613 if (getLangOptions().CPlusPlus) { 614 if (CheckCXXBooleanCondition(condExpr)) // C++ 6.4p4 615 return StmtError(); 616 } else if (!condType->isScalarType()) // C99 6.8.5p2 617 return StmtError(Diag(DoLoc, 618 diag::err_typecheck_statement_requires_scalar) 619 << condType << condExpr->getSourceRange()); 620 } 621 622 Stmt *bodyStmt = Body.takeAs<Stmt>(); 623 DiagnoseUnusedExprResult(bodyStmt); 624 625 Cond.release(); 626 return Owned(new (Context) DoStmt(bodyStmt, condExpr, DoLoc, 627 WhileLoc, CondRParen)); 628} 629 630Action::OwningStmtResult 631Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 632 StmtArg first, ExprArg second, ExprArg third, 633 SourceLocation RParenLoc, StmtArg body) { 634 Stmt *First = static_cast<Stmt*>(first.get()); 635 Expr *Second = static_cast<Expr*>(second.get()); 636 Expr *Third = static_cast<Expr*>(third.get()); 637 Stmt *Body = static_cast<Stmt*>(body.get()); 638 639 if (!getLangOptions().CPlusPlus) { 640 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 641 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 642 // declare identifiers for objects having storage class 'auto' or 643 // 'register'. 644 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 645 DI!=DE; ++DI) { 646 VarDecl *VD = dyn_cast<VarDecl>(*DI); 647 if (VD && VD->isBlockVarDecl() && !VD->hasLocalStorage()) 648 VD = 0; 649 if (VD == 0) 650 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 651 // FIXME: mark decl erroneous! 652 } 653 } 654 } 655 if (Second && !Second->isTypeDependent()) { 656 DefaultFunctionArrayConversion(Second); 657 QualType SecondType = Second->getType(); 658 659 if (getLangOptions().CPlusPlus) { 660 if (CheckCXXBooleanCondition(Second)) // C++ 6.4p4 661 return StmtError(); 662 } else if (!SecondType->isScalarType()) // C99 6.8.5p2 663 return StmtError(Diag(ForLoc, 664 diag::err_typecheck_statement_requires_scalar) 665 << SecondType << Second->getSourceRange()); 666 } 667 668 DiagnoseUnusedExprResult(First); 669 DiagnoseUnusedExprResult(Third); 670 DiagnoseUnusedExprResult(Body); 671 672 first.release(); 673 second.release(); 674 third.release(); 675 body.release(); 676 return Owned(new (Context) ForStmt(First, Second, Third, Body, ForLoc, 677 LParenLoc, RParenLoc)); 678} 679 680Action::OwningStmtResult 681Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 682 SourceLocation LParenLoc, 683 StmtArg first, ExprArg second, 684 SourceLocation RParenLoc, StmtArg body) { 685 Stmt *First = static_cast<Stmt*>(first.get()); 686 Expr *Second = static_cast<Expr*>(second.get()); 687 Stmt *Body = static_cast<Stmt*>(body.get()); 688 if (First) { 689 QualType FirstType; 690 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 691 if (!DS->isSingleDecl()) 692 return StmtError(Diag((*DS->decl_begin())->getLocation(), 693 diag::err_toomany_element_decls)); 694 695 Decl *D = DS->getSingleDecl(); 696 FirstType = cast<ValueDecl>(D)->getType(); 697 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 698 // declare identifiers for objects having storage class 'auto' or 699 // 'register'. 700 VarDecl *VD = cast<VarDecl>(D); 701 if (VD->isBlockVarDecl() && !VD->hasLocalStorage()) 702 return StmtError(Diag(VD->getLocation(), 703 diag::err_non_variable_decl_in_for)); 704 } else { 705 if (cast<Expr>(First)->isLvalue(Context) != Expr::LV_Valid) 706 return StmtError(Diag(First->getLocStart(), 707 diag::err_selector_element_not_lvalue) 708 << First->getSourceRange()); 709 710 FirstType = static_cast<Expr*>(First)->getType(); 711 } 712 if (!FirstType->isObjCObjectPointerType() && 713 !FirstType->isBlockPointerType()) 714 Diag(ForLoc, diag::err_selector_element_type) 715 << FirstType << First->getSourceRange(); 716 } 717 if (Second) { 718 DefaultFunctionArrayConversion(Second); 719 QualType SecondType = Second->getType(); 720 if (!SecondType->isObjCObjectPointerType()) 721 Diag(ForLoc, diag::err_collection_expr_type) 722 << SecondType << Second->getSourceRange(); 723 } 724 first.release(); 725 second.release(); 726 body.release(); 727 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 728 ForLoc, RParenLoc)); 729} 730 731Action::OwningStmtResult 732Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, 733 IdentifierInfo *LabelII) { 734 // If we are in a block, reject all gotos for now. 735 if (CurBlock) 736 return StmtError(Diag(GotoLoc, diag::err_goto_in_block)); 737 738 // Look up the record for this label identifier. 739 LabelStmt *&LabelDecl = getLabelMap()[LabelII]; 740 741 // If we haven't seen this label yet, create a forward reference. 742 if (LabelDecl == 0) 743 LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0); 744 745 return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc)); 746} 747 748Action::OwningStmtResult 749Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 750 ExprArg DestExp) { 751 // Convert operand to void* 752 Expr* E = DestExp.takeAs<Expr>(); 753 if (!E->isTypeDependent()) { 754 QualType ETy = E->getType(); 755 AssignConvertType ConvTy = 756 CheckSingleAssignmentConstraints(Context.VoidPtrTy, E); 757 if (DiagnoseAssignmentResult(ConvTy, StarLoc, Context.VoidPtrTy, ETy, 758 E, "passing")) 759 return StmtError(); 760 } 761 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 762} 763 764Action::OwningStmtResult 765Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 766 Scope *S = CurScope->getContinueParent(); 767 if (!S) { 768 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 769 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 770 } 771 772 return Owned(new (Context) ContinueStmt(ContinueLoc)); 773} 774 775Action::OwningStmtResult 776Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 777 Scope *S = CurScope->getBreakParent(); 778 if (!S) { 779 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 780 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 781 } 782 783 return Owned(new (Context) BreakStmt(BreakLoc)); 784} 785 786/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 787/// 788Action::OwningStmtResult 789Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 790 // If this is the first return we've seen in the block, infer the type of 791 // the block from it. 792 if (CurBlock->ReturnType.isNull()) { 793 if (RetValExp) { 794 // Don't call UsualUnaryConversions(), since we don't want to do 795 // integer promotions here. 796 DefaultFunctionArrayConversion(RetValExp); 797 CurBlock->ReturnType = RetValExp->getType(); 798 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 799 // We have to remove a 'const' added to copied-in variable which was 800 // part of the implementation spec. and not the actual qualifier for 801 // the variable. 802 if (CDRE->isConstQualAdded()) 803 CurBlock->ReturnType.removeConst(); 804 } 805 } else 806 CurBlock->ReturnType = Context.VoidTy; 807 } 808 QualType FnRetType = CurBlock->ReturnType; 809 810 if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) { 811 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 812 << getCurFunctionOrMethodDecl()->getDeclName(); 813 return StmtError(); 814 } 815 816 // Otherwise, verify that this result type matches the previous one. We are 817 // pickier with blocks than for normal functions because we don't have GCC 818 // compatibility to worry about here. 819 if (CurBlock->ReturnType->isVoidType()) { 820 if (RetValExp) { 821 Diag(ReturnLoc, diag::err_return_block_has_expr); 822 RetValExp->Destroy(Context); 823 RetValExp = 0; 824 } 825 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 826 } 827 828 if (!RetValExp) 829 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 830 831 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 832 // we have a non-void block with an expression, continue checking 833 QualType RetValType = RetValExp->getType(); 834 835 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 836 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 837 // function return. 838 839 // In C++ the return statement is handled via a copy initialization. 840 // the C version of which boils down to CheckSingleAssignmentConstraints. 841 // FIXME: Leaks RetValExp. 842 if (PerformCopyInitialization(RetValExp, FnRetType, "returning")) 843 return StmtError(); 844 845 if (RetValExp) CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 846 } 847 848 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 849} 850 851/// IsReturnCopyElidable - Whether returning @p RetExpr from a function that 852/// returns a @p RetType fulfills the criteria for copy elision (C++0x 12.8p15). 853static bool IsReturnCopyElidable(ASTContext &Ctx, QualType RetType, 854 Expr *RetExpr) { 855 QualType ExprType = RetExpr->getType(); 856 // - in a return statement in a function with ... 857 // ... a class return type ... 858 if (!RetType->isRecordType()) 859 return false; 860 // ... the same cv-unqualified type as the function return type ... 861 if (Ctx.getCanonicalType(RetType).getUnqualifiedType() != 862 Ctx.getCanonicalType(ExprType).getUnqualifiedType()) 863 return false; 864 // ... the expression is the name of a non-volatile automatic object ... 865 // We ignore parentheses here. 866 // FIXME: Is this compliant? 867 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens()); 868 if (!DR) 869 return false; 870 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 871 if (!VD) 872 return false; 873 return VD->hasLocalStorage() && !VD->getType()->isReferenceType() 874 && !VD->getType().isVolatileQualified(); 875} 876 877Action::OwningStmtResult 878Sema::ActOnReturnStmt(SourceLocation ReturnLoc, ExprArg rex) { 879 Expr *RetValExp = rex.takeAs<Expr>(); 880 if (CurBlock) 881 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 882 883 QualType FnRetType; 884 if (const FunctionDecl *FD = getCurFunctionDecl()) { 885 FnRetType = FD->getResultType(); 886 if (FD->hasAttr<NoReturnAttr>()) 887 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 888 << getCurFunctionOrMethodDecl()->getDeclName(); 889 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 890 FnRetType = MD->getResultType(); 891 else // If we don't have a function/method context, bail. 892 return StmtError(); 893 894 if (FnRetType->isVoidType()) { 895 if (RetValExp) {// C99 6.8.6.4p1 (ext_ since GCC warns) 896 unsigned D = diag::ext_return_has_expr; 897 if (RetValExp->getType()->isVoidType()) 898 D = diag::ext_return_has_void_expr; 899 900 // return (some void expression); is legal in C++. 901 if (D != diag::ext_return_has_void_expr || 902 !getLangOptions().CPlusPlus) { 903 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 904 Diag(ReturnLoc, D) 905 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 906 << RetValExp->getSourceRange(); 907 } 908 909 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp, true); 910 } 911 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 912 } 913 914 if (!RetValExp && !FnRetType->isDependentType()) { 915 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 916 // C99 6.8.6.4p1 (ext_ since GCC warns) 917 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 918 919 if (FunctionDecl *FD = getCurFunctionDecl()) 920 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 921 else 922 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 923 return Owned(new (Context) ReturnStmt(ReturnLoc, (Expr*)0)); 924 } 925 926 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 927 // we have a non-void function with an expression, continue checking 928 929 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 930 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 931 // function return. 932 933 // C++0x 12.8p15: When certain criteria are met, an implementation is 934 // allowed to omit the copy construction of a class object, [...] 935 // - in a return statement in a function with a class return type, when 936 // the expression is the name of a non-volatile automatic object with 937 // the same cv-unqualified type as the function return type, the copy 938 // operation can be omitted [...] 939 // C++0x 12.8p16: When the criteria for elision of a copy operation are met 940 // and the object to be copied is designated by an lvalue, overload 941 // resolution to select the constructor for the copy is first performed 942 // as if the object were designated by an rvalue. 943 // Note that we only compute Elidable if we're in C++0x, since we don't 944 // care otherwise. 945 bool Elidable = getLangOptions().CPlusPlus0x ? 946 IsReturnCopyElidable(Context, FnRetType, RetValExp) : 947 false; 948 949 // In C++ the return statement is handled via a copy initialization. 950 // the C version of which boils down to CheckSingleAssignmentConstraints. 951 // FIXME: Leaks RetValExp on error. 952 if (PerformCopyInitialization(RetValExp, FnRetType, "returning", Elidable)) 953 return StmtError(); 954 955 if (RetValExp) CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 956 } 957 958 if (RetValExp) 959 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp, true); 960 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 961} 962 963/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 964/// ignore "noop" casts in places where an lvalue is required by an inline asm. 965/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 966/// provide a strong guidance to not use it. 967/// 968/// This method checks to see if the argument is an acceptable l-value and 969/// returns false if it is a case we can handle. 970static bool CheckAsmLValue(const Expr *E, Sema &S) { 971 if (E->isLvalue(S.Context) == Expr::LV_Valid) 972 return false; // Cool, this is an lvalue. 973 974 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 975 // are supposed to allow. 976 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 977 if (E != E2 && E2->isLvalue(S.Context) == Expr::LV_Valid) { 978 if (!S.getLangOptions().HeinousExtensions) 979 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 980 << E->getSourceRange(); 981 else 982 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 983 << E->getSourceRange(); 984 // Accept, even if we emitted an error diagnostic. 985 return false; 986 } 987 988 // None of the above, just randomly invalid non-lvalue. 989 return true; 990} 991 992 993Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 994 bool IsSimple, 995 bool IsVolatile, 996 unsigned NumOutputs, 997 unsigned NumInputs, 998 std::string *Names, 999 MultiExprArg constraints, 1000 MultiExprArg exprs, 1001 ExprArg asmString, 1002 MultiExprArg clobbers, 1003 SourceLocation RParenLoc) { 1004 unsigned NumClobbers = clobbers.size(); 1005 StringLiteral **Constraints = 1006 reinterpret_cast<StringLiteral**>(constraints.get()); 1007 Expr **Exprs = reinterpret_cast<Expr **>(exprs.get()); 1008 StringLiteral *AsmString = cast<StringLiteral>((Expr *)asmString.get()); 1009 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1010 1011 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1012 1013 // The parser verifies that there is a string literal here. 1014 if (AsmString->isWide()) 1015 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1016 << AsmString->getSourceRange()); 1017 1018 for (unsigned i = 0; i != NumOutputs; i++) { 1019 StringLiteral *Literal = Constraints[i]; 1020 if (Literal->isWide()) 1021 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1022 << Literal->getSourceRange()); 1023 1024 TargetInfo::ConstraintInfo Info(Literal->getStrData(), 1025 Literal->getByteLength(), 1026 Names[i]); 1027 if (!Context.Target.validateOutputConstraint(Info)) 1028 return StmtError(Diag(Literal->getLocStart(), 1029 diag::err_asm_invalid_output_constraint) 1030 << Info.getConstraintStr()); 1031 1032 // Check that the output exprs are valid lvalues. 1033 Expr *OutputExpr = Exprs[i]; 1034 if (CheckAsmLValue(OutputExpr, *this)) { 1035 return StmtError(Diag(OutputExpr->getLocStart(), 1036 diag::err_asm_invalid_lvalue_in_output) 1037 << OutputExpr->getSourceRange()); 1038 } 1039 1040 OutputConstraintInfos.push_back(Info); 1041 } 1042 1043 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1044 1045 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1046 StringLiteral *Literal = Constraints[i]; 1047 if (Literal->isWide()) 1048 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1049 << Literal->getSourceRange()); 1050 1051 TargetInfo::ConstraintInfo Info(Literal->getStrData(), 1052 Literal->getByteLength(), 1053 Names[i]); 1054 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1055 NumOutputs, Info)) { 1056 return StmtError(Diag(Literal->getLocStart(), 1057 diag::err_asm_invalid_input_constraint) 1058 << Info.getConstraintStr()); 1059 } 1060 1061 Expr *InputExpr = Exprs[i]; 1062 1063 // Only allow void types for memory constraints. 1064 if (Info.allowsMemory() && !Info.allowsRegister()) { 1065 if (CheckAsmLValue(InputExpr, *this)) 1066 return StmtError(Diag(InputExpr->getLocStart(), 1067 diag::err_asm_invalid_lvalue_in_input) 1068 << Info.getConstraintStr() 1069 << InputExpr->getSourceRange()); 1070 } 1071 1072 if (Info.allowsRegister()) { 1073 if (InputExpr->getType()->isVoidType()) { 1074 return StmtError(Diag(InputExpr->getLocStart(), 1075 diag::err_asm_invalid_type_in_input) 1076 << InputExpr->getType() << Info.getConstraintStr() 1077 << InputExpr->getSourceRange()); 1078 } 1079 } 1080 1081 DefaultFunctionArrayConversion(Exprs[i]); 1082 1083 InputConstraintInfos.push_back(Info); 1084 } 1085 1086 // Check that the clobbers are valid. 1087 for (unsigned i = 0; i != NumClobbers; i++) { 1088 StringLiteral *Literal = Clobbers[i]; 1089 if (Literal->isWide()) 1090 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1091 << Literal->getSourceRange()); 1092 1093 std::string Clobber(Literal->getStrData(), 1094 Literal->getStrData() + 1095 Literal->getByteLength()); 1096 1097 if (!Context.Target.isValidGCCRegisterName(Clobber.c_str())) 1098 return StmtError(Diag(Literal->getLocStart(), 1099 diag::err_asm_unknown_register_name) << Clobber); 1100 } 1101 1102 constraints.release(); 1103 exprs.release(); 1104 asmString.release(); 1105 clobbers.release(); 1106 AsmStmt *NS = 1107 new (Context) AsmStmt(AsmLoc, IsSimple, IsVolatile, NumOutputs, NumInputs, 1108 Names, Constraints, Exprs, AsmString, NumClobbers, 1109 Clobbers, RParenLoc); 1110 // Validate the asm string, ensuring it makes sense given the operands we 1111 // have. 1112 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1113 unsigned DiagOffs; 1114 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1115 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1116 << AsmString->getSourceRange(); 1117 DeleteStmt(NS); 1118 return StmtError(); 1119 } 1120 1121 // Validate tied input operands for type mismatches. 1122 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1123 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1124 1125 // If this is a tied constraint, verify that the output and input have 1126 // either exactly the same type, or that they are int/ptr operands with the 1127 // same size (int/long, int*/long, are ok etc). 1128 if (!Info.hasTiedOperand()) continue; 1129 1130 unsigned TiedTo = Info.getTiedOperand(); 1131 Expr *OutputExpr = Exprs[TiedTo]; 1132 Expr *InputExpr = Exprs[i+NumOutputs]; 1133 QualType InTy = InputExpr->getType(); 1134 QualType OutTy = OutputExpr->getType(); 1135 if (Context.hasSameType(InTy, OutTy)) 1136 continue; // All types can be tied to themselves. 1137 1138 // Int/ptr operands have some special cases that we allow. 1139 if ((OutTy->isIntegerType() || OutTy->isPointerType()) && 1140 (InTy->isIntegerType() || InTy->isPointerType())) { 1141 1142 // They are ok if they are the same size. Tying void* to int is ok if 1143 // they are the same size, for example. This also allows tying void* to 1144 // int*. 1145 uint64_t OutSize = Context.getTypeSize(OutTy); 1146 uint64_t InSize = Context.getTypeSize(InTy); 1147 if (OutSize == InSize) 1148 continue; 1149 1150 // If the smaller input/output operand is not mentioned in the asm string, 1151 // then we can promote it and the asm string won't notice. Check this 1152 // case now. 1153 bool SmallerValueMentioned = false; 1154 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1155 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1156 if (!Piece.isOperand()) continue; 1157 1158 // If this is a reference to the input and if the input was the smaller 1159 // one, then we have to reject this asm. 1160 if (Piece.getOperandNo() == i+NumOutputs) { 1161 if (InSize < OutSize) { 1162 SmallerValueMentioned = true; 1163 break; 1164 } 1165 } 1166 1167 // If this is a reference to the input and if the input was the smaller 1168 // one, then we have to reject this asm. 1169 if (Piece.getOperandNo() == TiedTo) { 1170 if (InSize > OutSize) { 1171 SmallerValueMentioned = true; 1172 break; 1173 } 1174 } 1175 } 1176 1177 // If the smaller value wasn't mentioned in the asm string, and if the 1178 // output was a register, just extend the shorter one to the size of the 1179 // larger one. 1180 if (!SmallerValueMentioned && 1181 OutputConstraintInfos[TiedTo].allowsRegister()) 1182 continue; 1183 } 1184 1185 Diag(InputExpr->getLocStart(), 1186 diag::err_asm_tying_incompatible_types) 1187 << InTy << OutTy << OutputExpr->getSourceRange() 1188 << InputExpr->getSourceRange(); 1189 DeleteStmt(NS); 1190 return StmtError(); 1191 } 1192 1193 return Owned(NS); 1194} 1195 1196Action::OwningStmtResult 1197Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1198 SourceLocation RParen, DeclPtrTy Parm, 1199 StmtArg Body, StmtArg catchList) { 1200 Stmt *CatchList = catchList.takeAs<Stmt>(); 1201 ParmVarDecl *PVD = cast_or_null<ParmVarDecl>(Parm.getAs<Decl>()); 1202 1203 // PVD == 0 implies @catch(...). 1204 if (PVD) { 1205 // If we already know the decl is invalid, reject it. 1206 if (PVD->isInvalidDecl()) 1207 return StmtError(); 1208 1209 if (!PVD->getType()->isObjCObjectPointerType()) 1210 return StmtError(Diag(PVD->getLocation(), 1211 diag::err_catch_param_not_objc_type)); 1212 if (PVD->getType()->isObjCQualifiedIdType()) 1213 return StmtError(Diag(PVD->getLocation(), 1214 diag::err_illegal_qualifiers_on_catch_parm)); 1215 } 1216 1217 ObjCAtCatchStmt *CS = new (Context) ObjCAtCatchStmt(AtLoc, RParen, 1218 PVD, Body.takeAs<Stmt>(), CatchList); 1219 return Owned(CatchList ? CatchList : CS); 1220} 1221 1222Action::OwningStmtResult 1223Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, StmtArg Body) { 1224 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, 1225 static_cast<Stmt*>(Body.release()))); 1226} 1227 1228Action::OwningStmtResult 1229Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, 1230 StmtArg Try, StmtArg Catch, StmtArg Finally) { 1231 CurFunctionNeedsScopeChecking = true; 1232 return Owned(new (Context) ObjCAtTryStmt(AtLoc, Try.takeAs<Stmt>(), 1233 Catch.takeAs<Stmt>(), 1234 Finally.takeAs<Stmt>())); 1235} 1236 1237Action::OwningStmtResult 1238Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg expr,Scope *CurScope) { 1239 Expr *ThrowExpr = expr.takeAs<Expr>(); 1240 if (!ThrowExpr) { 1241 // @throw without an expression designates a rethrow (which much occur 1242 // in the context of an @catch clause). 1243 Scope *AtCatchParent = CurScope; 1244 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1245 AtCatchParent = AtCatchParent->getParent(); 1246 if (!AtCatchParent) 1247 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1248 } else { 1249 QualType ThrowType = ThrowExpr->getType(); 1250 // Make sure the expression type is an ObjC pointer or "void *". 1251 if (!ThrowType->isObjCObjectPointerType()) { 1252 const PointerType *PT = ThrowType->getAs<PointerType>(); 1253 if (!PT || !PT->getPointeeType()->isVoidType()) 1254 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1255 << ThrowExpr->getType() << ThrowExpr->getSourceRange()); 1256 } 1257 } 1258 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, ThrowExpr)); 1259} 1260 1261Action::OwningStmtResult 1262Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprArg SynchExpr, 1263 StmtArg SynchBody) { 1264 CurFunctionNeedsScopeChecking = true; 1265 1266 // Make sure the expression type is an ObjC pointer or "void *". 1267 Expr *SyncExpr = static_cast<Expr*>(SynchExpr.get()); 1268 if (!SyncExpr->getType()->isObjCObjectPointerType()) { 1269 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1270 if (!PT || !PT->getPointeeType()->isVoidType()) 1271 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1272 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1273 } 1274 1275 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, 1276 SynchExpr.takeAs<Stmt>(), 1277 SynchBody.takeAs<Stmt>())); 1278} 1279 1280/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1281/// and creates a proper catch handler from them. 1282Action::OwningStmtResult 1283Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclPtrTy ExDecl, 1284 StmtArg HandlerBlock) { 1285 // There's nothing to test that ActOnExceptionDecl didn't already test. 1286 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1287 cast_or_null<VarDecl>(ExDecl.getAs<Decl>()), 1288 HandlerBlock.takeAs<Stmt>())); 1289} 1290 1291class TypeWithHandler { 1292 QualType t; 1293 CXXCatchStmt *stmt; 1294public: 1295 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1296 : t(type), stmt(statement) {} 1297 1298 bool operator<(const TypeWithHandler &y) const { 1299 if (t.getTypePtr() < y.t.getTypePtr()) 1300 return true; 1301 else if (t.getTypePtr() > y.t.getTypePtr()) 1302 return false; 1303 else if (t.getCVRQualifiers() < y.t.getCVRQualifiers()) 1304 return true; 1305 else if (t.getCVRQualifiers() < y.t.getCVRQualifiers()) 1306 return false; 1307 else 1308 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1309 } 1310 1311 bool operator==(const TypeWithHandler& other) const { 1312 return t.getTypePtr() == other.t.getTypePtr() 1313 && t.getCVRQualifiers() == other.t.getCVRQualifiers(); 1314 } 1315 1316 QualType getQualType() const { return t; } 1317 CXXCatchStmt *getCatchStmt() const { return stmt; } 1318 SourceLocation getTypeSpecStartLoc() const { 1319 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1320 } 1321}; 1322 1323/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1324/// handlers and creates a try statement from them. 1325Action::OwningStmtResult 1326Sema::ActOnCXXTryBlock(SourceLocation TryLoc, StmtArg TryBlock, 1327 MultiStmtArg RawHandlers) { 1328 unsigned NumHandlers = RawHandlers.size(); 1329 assert(NumHandlers > 0 && 1330 "The parser shouldn't call this if there are no handlers."); 1331 Stmt **Handlers = reinterpret_cast<Stmt**>(RawHandlers.get()); 1332 1333 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1334 1335 for(unsigned i = 0; i < NumHandlers; ++i) { 1336 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1337 if (!Handler->getExceptionDecl()) { 1338 if (i < NumHandlers - 1) 1339 return StmtError(Diag(Handler->getLocStart(), 1340 diag::err_early_catch_all)); 1341 1342 continue; 1343 } 1344 1345 const QualType CaughtType = Handler->getCaughtType(); 1346 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1347 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1348 } 1349 1350 // Detect handlers for the same type as an earlier one. 1351 if (NumHandlers > 1) { 1352 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1353 1354 TypeWithHandler prev = TypesWithHandlers[0]; 1355 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1356 TypeWithHandler curr = TypesWithHandlers[i]; 1357 1358 if (curr == prev) { 1359 Diag(curr.getTypeSpecStartLoc(), 1360 diag::warn_exception_caught_by_earlier_handler) 1361 << curr.getCatchStmt()->getCaughtType().getAsString(); 1362 Diag(prev.getTypeSpecStartLoc(), 1363 diag::note_previous_exception_handler) 1364 << prev.getCatchStmt()->getCaughtType().getAsString(); 1365 } 1366 1367 prev = curr; 1368 } 1369 } 1370 1371 // FIXME: We should detect handlers that cannot catch anything because an 1372 // earlier handler catches a superclass. Need to find a method that is not 1373 // quadratic for this. 1374 // Neither of these are explicitly forbidden, but every compiler detects them 1375 // and warns. 1376 1377 CurFunctionNeedsScopeChecking = true; 1378 RawHandlers.release(); 1379 return Owned(new (Context) CXXTryStmt(TryLoc, 1380 static_cast<Stmt*>(TryBlock.release()), 1381 Handlers, NumHandlers)); 1382} 1383