ParseInit.cpp revision 226633
1138568Ssam//===--- ParseInit.cpp - Initializer Parsing ------------------------------===// 2138568Ssam// 3138568Ssam// The LLVM Compiler Infrastructure 4138568Ssam// 5138568Ssam// This file is distributed under the University of Illinois Open Source 6138568Ssam// License. See LICENSE.TXT for details. 7138568Ssam// 8138568Ssam//===----------------------------------------------------------------------===// 9138568Ssam// 10138568Ssam// This file implements initializer parsing as specified by C99 6.7.8. 11138568Ssam// 12138568Ssam//===----------------------------------------------------------------------===// 13138568Ssam 14138568Ssam#include "clang/Parse/Parser.h" 15138568Ssam#include "clang/Parse/ParseDiagnostic.h" 16138568Ssam#include "RAIIObjectsForParser.h" 17138568Ssam#include "clang/Sema/Designator.h" 18138568Ssam#include "clang/Sema/Scope.h" 19138568Ssam#include "llvm/ADT/SmallString.h" 20138568Ssam#include "llvm/Support/raw_ostream.h" 21138568Ssamusing namespace clang; 22138568Ssam 23138568Ssam 24138568Ssam/// MayBeDesignationStart - Return true if this token might be the start of a 25138568Ssam/// designator. If we can tell it is impossible that it is a designator, return 26138568Ssam/// false. 27138568Ssamstatic bool MayBeDesignationStart(tok::TokenKind K, Preprocessor &PP) { 28138568Ssam switch (K) { 29138568Ssam default: return false; 30138568Ssam case tok::period: // designator: '.' identifier 31138568Ssam case tok::l_square: // designator: array-designator 32138568Ssam return true; 33138568Ssam case tok::identifier: // designation: identifier ':' 34138568Ssam return PP.LookAhead(0).is(tok::colon); 35138568Ssam } 36138568Ssam} 37138568Ssam 38138568Ssamstatic void CheckArrayDesignatorSyntax(Parser &P, SourceLocation Loc, 39138568Ssam Designation &Desig) { 40138568Ssam // If we have exactly one array designator, this used the GNU 41138568Ssam // 'designation: array-designator' extension, otherwise there should be no 42138568Ssam // designators at all! 43138568Ssam if (Desig.getNumDesignators() == 1 && 44138568Ssam (Desig.getDesignator(0).isArrayDesignator() || 45138568Ssam Desig.getDesignator(0).isArrayRangeDesignator())) 46138568Ssam P.Diag(Loc, diag::ext_gnu_missing_equal_designator); 47138568Ssam else if (Desig.getNumDesignators() > 0) 48138568Ssam P.Diag(Loc, diag::err_expected_equal_designator); 49138568Ssam} 50138568Ssam 51138568Ssam/// ParseInitializerWithPotentialDesignator - Parse the 'initializer' production 52138568Ssam/// checking to see if the token stream starts with a designator. 53138568Ssam/// 54138568Ssam/// designation: 55138568Ssam/// designator-list '=' 56138568Ssam/// [GNU] array-designator 57138568Ssam/// [GNU] identifier ':' 58138568Ssam/// 59138568Ssam/// designator-list: 60138568Ssam/// designator 61138568Ssam/// designator-list designator 62138568Ssam/// 63138568Ssam/// designator: 64138568Ssam/// array-designator 65138568Ssam/// '.' identifier 66138568Ssam/// 67138568Ssam/// array-designator: 68138568Ssam/// '[' constant-expression ']' 69138568Ssam/// [GNU] '[' constant-expression '...' constant-expression ']' 70138568Ssam/// 71138568Ssam/// NOTE: [OBC] allows '[ objc-receiver objc-message-args ]' as an 72138568Ssam/// initializer (because it is an expression). We need to consider this case 73138568Ssam/// when parsing array designators. 74138568Ssam/// 75138568SsamExprResult Parser::ParseInitializerWithPotentialDesignator() { 76138568Ssam 77138568Ssam // If this is the old-style GNU extension: 78138568Ssam // designation ::= identifier ':' 79138568Ssam // Handle it as a field designator. Otherwise, this must be the start of a 80138568Ssam // normal expression. 81138568Ssam if (Tok.is(tok::identifier)) { 82138568Ssam const IdentifierInfo *FieldName = Tok.getIdentifierInfo(); 83138568Ssam 84138568Ssam llvm::SmallString<256> NewSyntax; 85138568Ssam llvm::raw_svector_ostream(NewSyntax) << '.' << FieldName->getName() 86138568Ssam << " = "; 87138568Ssam 88138568Ssam SourceLocation NameLoc = ConsumeToken(); // Eat the identifier. 89138568Ssam 90138568Ssam assert(Tok.is(tok::colon) && "MayBeDesignationStart not working properly!"); 91138568Ssam SourceLocation ColonLoc = ConsumeToken(); 92138568Ssam 93138568Ssam Diag(NameLoc, diag::ext_gnu_old_style_field_designator) 94138568Ssam << FixItHint::CreateReplacement(SourceRange(NameLoc, ColonLoc), 95138568Ssam NewSyntax.str()); 96138568Ssam 97138568Ssam Designation D; 98138568Ssam D.AddDesignator(Designator::getField(FieldName, SourceLocation(), NameLoc)); 99138568Ssam return Actions.ActOnDesignatedInitializer(D, ColonLoc, true, 100138568Ssam ParseInitializer()); 101138568Ssam } 102138568Ssam 103138568Ssam // Desig - This is initialized when we see our first designator. We may have 104138568Ssam // an objc message send with no designator, so we don't want to create this 105138568Ssam // eagerly. 106138568Ssam Designation Desig; 107138568Ssam 108138568Ssam // Parse each designator in the designator list until we find an initializer. 109138568Ssam while (Tok.is(tok::period) || Tok.is(tok::l_square)) { 110138568Ssam if (Tok.is(tok::period)) { 111138568Ssam // designator: '.' identifier 112138568Ssam SourceLocation DotLoc = ConsumeToken(); 113138568Ssam 114138568Ssam if (Tok.isNot(tok::identifier)) { 115138568Ssam Diag(Tok.getLocation(), diag::err_expected_field_designator); 116138568Ssam return ExprError(); 117138568Ssam } 118138568Ssam 119138568Ssam Desig.AddDesignator(Designator::getField(Tok.getIdentifierInfo(), DotLoc, 120138568Ssam Tok.getLocation())); 121138568Ssam ConsumeToken(); // Eat the identifier. 122138568Ssam continue; 123138568Ssam } 124138568Ssam 125138568Ssam // We must have either an array designator now or an objc message send. 126138568Ssam assert(Tok.is(tok::l_square) && "Unexpected token!"); 127138568Ssam 128138568Ssam // Handle the two forms of array designator: 129138568Ssam // array-designator: '[' constant-expression ']' 130138568Ssam // array-designator: '[' constant-expression '...' constant-expression ']' 131138568Ssam // 132138568Ssam // Also, we have to handle the case where the expression after the 133138568Ssam // designator an an objc message send: '[' objc-message-expr ']'. 134138568Ssam // Interesting cases are: 135138568Ssam // [foo bar] -> objc message send 136138568Ssam // [foo] -> array designator 137138568Ssam // [foo ... bar] -> array designator 138138568Ssam // [4][foo bar] -> obsolete GNU designation with objc message send. 139138568Ssam // 140138568Ssam InMessageExpressionRAIIObject InMessage(*this, true); 141138568Ssam 142138568Ssam BalancedDelimiterTracker T(*this, tok::l_square); 143138568Ssam T.consumeOpen(); 144138568Ssam SourceLocation StartLoc = T.getOpenLocation(); 145138568Ssam 146138568Ssam ExprResult Idx; 147138568Ssam 148138568Ssam // If Objective-C is enabled and this is a typename (class message 149138568Ssam // send) or send to 'super', parse this as a message send 150138568Ssam // expression. We handle C++ and C separately, since C++ requires 151138568Ssam // much more complicated parsing. 152138568Ssam if (getLang().ObjC1 && getLang().CPlusPlus) { 153138568Ssam // Send to 'super'. 154138568Ssam if (Tok.is(tok::identifier) && Tok.getIdentifierInfo() == Ident_super && 155138568Ssam NextToken().isNot(tok::period) && 156138568Ssam getCurScope()->isInObjcMethodScope()) { 157138568Ssam CheckArrayDesignatorSyntax(*this, StartLoc, Desig); 158138568Ssam return ParseAssignmentExprWithObjCMessageExprStart(StartLoc, 159138568Ssam ConsumeToken(), 160138568Ssam ParsedType(), 161138568Ssam 0); 162138568Ssam } 163138568Ssam 164138568Ssam // Parse the receiver, which is either a type or an expression. 165138568Ssam bool IsExpr; 166138568Ssam void *TypeOrExpr; 167138568Ssam if (ParseObjCXXMessageReceiver(IsExpr, TypeOrExpr)) { 168138568Ssam SkipUntil(tok::r_square); 169138568Ssam return ExprError(); 170138568Ssam } 171138568Ssam 172138568Ssam // If the receiver was a type, we have a class message; parse 173138568Ssam // the rest of it. 174138568Ssam if (!IsExpr) { 175138568Ssam CheckArrayDesignatorSyntax(*this, StartLoc, Desig); 176138568Ssam return ParseAssignmentExprWithObjCMessageExprStart(StartLoc, 177138568Ssam SourceLocation(), 178138568Ssam ParsedType::getFromOpaquePtr(TypeOrExpr), 179138568Ssam 0); 180138568Ssam } 181138568Ssam 182138568Ssam // If the receiver was an expression, we still don't know 183138568Ssam // whether we have a message send or an array designator; just 184138568Ssam // adopt the expression for further analysis below. 185138568Ssam // FIXME: potentially-potentially evaluated expression above? 186138568Ssam Idx = ExprResult(static_cast<Expr*>(TypeOrExpr)); 187138568Ssam } else if (getLang().ObjC1 && Tok.is(tok::identifier)) { 188138568Ssam IdentifierInfo *II = Tok.getIdentifierInfo(); 189138568Ssam SourceLocation IILoc = Tok.getLocation(); 190138568Ssam ParsedType ReceiverType; 191138568Ssam // Three cases. This is a message send to a type: [type foo] 192138568Ssam // This is a message send to super: [super foo] 193138568Ssam // This is a message sent to an expr: [super.bar foo] 194138568Ssam switch (Sema::ObjCMessageKind Kind 195138568Ssam = Actions.getObjCMessageKind(getCurScope(), II, IILoc, 196138568Ssam II == Ident_super, 197138568Ssam NextToken().is(tok::period), 198138568Ssam ReceiverType)) { 199138568Ssam case Sema::ObjCSuperMessage: 200138568Ssam case Sema::ObjCClassMessage: 201138568Ssam CheckArrayDesignatorSyntax(*this, StartLoc, Desig); 202138568Ssam if (Kind == Sema::ObjCSuperMessage) 203138568Ssam return ParseAssignmentExprWithObjCMessageExprStart(StartLoc, 204138568Ssam ConsumeToken(), 205138568Ssam ParsedType(), 206138568Ssam 0); 207138568Ssam ConsumeToken(); // the identifier 208138568Ssam if (!ReceiverType) { 209138568Ssam SkipUntil(tok::r_square); 210138568Ssam return ExprError(); 211138568Ssam } 212138568Ssam 213138568Ssam return ParseAssignmentExprWithObjCMessageExprStart(StartLoc, 214138568Ssam SourceLocation(), 215138568Ssam ReceiverType, 216138568Ssam 0); 217138568Ssam 218138568Ssam case Sema::ObjCInstanceMessage: 219138568Ssam // Fall through; we'll just parse the expression and 220138568Ssam // (possibly) treat this like an Objective-C message send 221138568Ssam // later. 222138568Ssam break; 223138568Ssam } 224138568Ssam } 225138568Ssam 226138568Ssam // Parse the index expression, if we haven't already gotten one 227138568Ssam // above (which can only happen in Objective-C++). 228138568Ssam // Note that we parse this as an assignment expression, not a constant 229138568Ssam // expression (allowing *=, =, etc) to handle the objc case. Sema needs 230138568Ssam // to validate that the expression is a constant. 231138568Ssam // FIXME: We also need to tell Sema that we're in a 232138568Ssam // potentially-potentially evaluated context. 233138568Ssam if (!Idx.get()) { 234138568Ssam Idx = ParseAssignmentExpression(); 235138568Ssam if (Idx.isInvalid()) { 236138568Ssam SkipUntil(tok::r_square); 237138568Ssam return move(Idx); 238138568Ssam } 239138568Ssam } 240138568Ssam 241138568Ssam // Given an expression, we could either have a designator (if the next 242138568Ssam // tokens are '...' or ']' or an objc message send. If this is an objc 243138568Ssam // message send, handle it now. An objc-message send is the start of 244138568Ssam // an assignment-expression production. 245138568Ssam if (getLang().ObjC1 && Tok.isNot(tok::ellipsis) && 246138568Ssam Tok.isNot(tok::r_square)) { 247138568Ssam CheckArrayDesignatorSyntax(*this, Tok.getLocation(), Desig); 248138568Ssam return ParseAssignmentExprWithObjCMessageExprStart(StartLoc, 249138568Ssam SourceLocation(), 250138568Ssam ParsedType(), 251138568Ssam Idx.take()); 252138568Ssam } 253138568Ssam 254138568Ssam // If this is a normal array designator, remember it. 255138568Ssam if (Tok.isNot(tok::ellipsis)) { 256138568Ssam Desig.AddDesignator(Designator::getArray(Idx.release(), StartLoc)); 257138568Ssam } else { 258138568Ssam // Handle the gnu array range extension. 259138568Ssam Diag(Tok, diag::ext_gnu_array_range); 260138568Ssam SourceLocation EllipsisLoc = ConsumeToken(); 261138568Ssam 262138568Ssam ExprResult RHS(ParseConstantExpression()); 263138568Ssam if (RHS.isInvalid()) { 264138568Ssam SkipUntil(tok::r_square); 265138568Ssam return move(RHS); 266138568Ssam } 267138568Ssam Desig.AddDesignator(Designator::getArrayRange(Idx.release(), 268138568Ssam RHS.release(), 269138568Ssam StartLoc, EllipsisLoc)); 270138568Ssam } 271138568Ssam 272138568Ssam T.consumeClose(); 273138568Ssam Desig.getDesignator(Desig.getNumDesignators() - 1).setRBracketLoc( 274138568Ssam T.getCloseLocation()); 275138568Ssam } 276138568Ssam 277138568Ssam // Okay, we're done with the designator sequence. We know that there must be 278138568Ssam // at least one designator, because the only case we can get into this method 279138568Ssam // without a designator is when we have an objc message send. That case is 280138568Ssam // handled and returned from above. 281138568Ssam assert(!Desig.empty() && "Designator is empty?"); 282138568Ssam 283138568Ssam // Handle a normal designator sequence end, which is an equal. 284138568Ssam if (Tok.is(tok::equal)) { 285138568Ssam SourceLocation EqualLoc = ConsumeToken(); 286138568Ssam return Actions.ActOnDesignatedInitializer(Desig, EqualLoc, false, 287138568Ssam ParseInitializer()); 288138568Ssam } 289138568Ssam 290138568Ssam // We read some number of designators and found something that isn't an = or 291138568Ssam // an initializer. If we have exactly one array designator, this 292138568Ssam // is the GNU 'designation: array-designator' extension. Otherwise, it is a 293138568Ssam // parse error. 294138568Ssam if (Desig.getNumDesignators() == 1 && 295138568Ssam (Desig.getDesignator(0).isArrayDesignator() || 296138568Ssam Desig.getDesignator(0).isArrayRangeDesignator())) { 297138568Ssam Diag(Tok, diag::ext_gnu_missing_equal_designator) 298138568Ssam << FixItHint::CreateInsertion(Tok.getLocation(), "= "); 299138568Ssam return Actions.ActOnDesignatedInitializer(Desig, Tok.getLocation(), 300138568Ssam true, ParseInitializer()); 301138568Ssam } 302 303 Diag(Tok, diag::err_expected_equal_designator); 304 return ExprError(); 305} 306 307 308/// ParseBraceInitializer - Called when parsing an initializer that has a 309/// leading open brace. 310/// 311/// initializer: [C99 6.7.8] 312/// '{' initializer-list '}' 313/// '{' initializer-list ',' '}' 314/// [GNU] '{' '}' 315/// 316/// initializer-list: 317/// designation[opt] initializer ...[opt] 318/// initializer-list ',' designation[opt] initializer ...[opt] 319/// 320ExprResult Parser::ParseBraceInitializer() { 321 InMessageExpressionRAIIObject InMessage(*this, false); 322 323 BalancedDelimiterTracker T(*this, tok::l_brace); 324 T.consumeOpen(); 325 SourceLocation LBraceLoc = T.getOpenLocation(); 326 327 /// InitExprs - This is the actual list of expressions contained in the 328 /// initializer. 329 ExprVector InitExprs(Actions); 330 331 if (Tok.is(tok::r_brace)) { 332 // Empty initializers are a C++ feature and a GNU extension to C. 333 if (!getLang().CPlusPlus) 334 Diag(LBraceLoc, diag::ext_gnu_empty_initializer); 335 // Match the '}'. 336 return Actions.ActOnInitList(LBraceLoc, MultiExprArg(Actions), 337 ConsumeBrace()); 338 } 339 340 bool InitExprsOk = true; 341 342 while (1) { 343 // Parse: designation[opt] initializer 344 345 // If we know that this cannot be a designation, just parse the nested 346 // initializer directly. 347 ExprResult SubElt; 348 if (MayBeDesignationStart(Tok.getKind(), PP)) 349 SubElt = ParseInitializerWithPotentialDesignator(); 350 else 351 SubElt = ParseInitializer(); 352 353 if (Tok.is(tok::ellipsis)) 354 SubElt = Actions.ActOnPackExpansion(SubElt.get(), ConsumeToken()); 355 356 // If we couldn't parse the subelement, bail out. 357 if (!SubElt.isInvalid()) { 358 InitExprs.push_back(SubElt.release()); 359 } else { 360 InitExprsOk = false; 361 362 // We have two ways to try to recover from this error: if the code looks 363 // grammatically ok (i.e. we have a comma coming up) try to continue 364 // parsing the rest of the initializer. This allows us to emit 365 // diagnostics for later elements that we find. If we don't see a comma, 366 // assume there is a parse error, and just skip to recover. 367 // FIXME: This comment doesn't sound right. If there is a r_brace 368 // immediately, it can't be an error, since there is no other way of 369 // leaving this loop except through this if. 370 if (Tok.isNot(tok::comma)) { 371 SkipUntil(tok::r_brace, false, true); 372 break; 373 } 374 } 375 376 // If we don't have a comma continued list, we're done. 377 if (Tok.isNot(tok::comma)) break; 378 379 // TODO: save comma locations if some client cares. 380 ConsumeToken(); 381 382 // Handle trailing comma. 383 if (Tok.is(tok::r_brace)) break; 384 } 385 386 bool closed = !T.consumeClose(); 387 388 if (InitExprsOk && closed) 389 return Actions.ActOnInitList(LBraceLoc, move_arg(InitExprs), 390 T.getCloseLocation()); 391 392 return ExprError(); // an error occurred. 393} 394 395