1 //===--- ParseExpr.cpp - Expression Parsing -------------------------------===//
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 /// \file
11 /// \brief Provides the Expression parsing implementation.
12 ///
13 /// Expressions in C99 basically consist of a bunch of binary operators with
14 /// unary operators and other random stuff at the leaves.
15 ///
16 /// In the C99 grammar, these unary operators bind tightest and are represented
17 /// as the 'cast-expression' production.  Everything else is either a binary
18 /// operator (e.g. '/') or a ternary operator ("?:").  The unary leaves are
19 /// handled by ParseCastExpression, the higher level pieces are handled by
20 /// ParseBinaryExpression.
21 ///
22 //===----------------------------------------------------------------------===//
23 
24 #include "clang/Parse/Parser.h"
25 #include "RAIIObjectsForParser.h"
26 #include "clang/AST/ASTContext.h"
27 #include "clang/Basic/PrettyStackTrace.h"
28 #include "clang/Sema/DeclSpec.h"
29 #include "clang/Sema/ParsedTemplate.h"
30 #include "clang/Sema/Scope.h"
31 #include "clang/Sema/TypoCorrection.h"
32 #include "llvm/ADT/SmallString.h"
33 #include "llvm/ADT/SmallVector.h"
34 using namespace clang;
35 
36 /// \brief Simple precedence-based parser for binary/ternary operators.
37 ///
38 /// Note: we diverge from the C99 grammar when parsing the assignment-expression
39 /// production.  C99 specifies that the LHS of an assignment operator should be
40 /// parsed as a unary-expression, but consistency dictates that it be a
41 /// conditional-expession.  In practice, the important thing here is that the
42 /// LHS of an assignment has to be an l-value, which productions between
43 /// unary-expression and conditional-expression don't produce.  Because we want
44 /// consistency, we parse the LHS as a conditional-expression, then check for
45 /// l-value-ness in semantic analysis stages.
46 ///
47 /// \verbatim
48 ///       pm-expression: [C++ 5.5]
49 ///         cast-expression
50 ///         pm-expression '.*' cast-expression
51 ///         pm-expression '->*' cast-expression
52 ///
53 ///       multiplicative-expression: [C99 6.5.5]
54 ///     Note: in C++, apply pm-expression instead of cast-expression
55 ///         cast-expression
56 ///         multiplicative-expression '*' cast-expression
57 ///         multiplicative-expression '/' cast-expression
58 ///         multiplicative-expression '%' cast-expression
59 ///
60 ///       additive-expression: [C99 6.5.6]
61 ///         multiplicative-expression
62 ///         additive-expression '+' multiplicative-expression
63 ///         additive-expression '-' multiplicative-expression
64 ///
65 ///       shift-expression: [C99 6.5.7]
66 ///         additive-expression
67 ///         shift-expression '<<' additive-expression
68 ///         shift-expression '>>' additive-expression
69 ///
70 ///       relational-expression: [C99 6.5.8]
71 ///         shift-expression
72 ///         relational-expression '<' shift-expression
73 ///         relational-expression '>' shift-expression
74 ///         relational-expression '<=' shift-expression
75 ///         relational-expression '>=' shift-expression
76 ///
77 ///       equality-expression: [C99 6.5.9]
78 ///         relational-expression
79 ///         equality-expression '==' relational-expression
80 ///         equality-expression '!=' relational-expression
81 ///
82 ///       AND-expression: [C99 6.5.10]
83 ///         equality-expression
84 ///         AND-expression '&' equality-expression
85 ///
86 ///       exclusive-OR-expression: [C99 6.5.11]
87 ///         AND-expression
88 ///         exclusive-OR-expression '^' AND-expression
89 ///
90 ///       inclusive-OR-expression: [C99 6.5.12]
91 ///         exclusive-OR-expression
92 ///         inclusive-OR-expression '|' exclusive-OR-expression
93 ///
94 ///       logical-AND-expression: [C99 6.5.13]
95 ///         inclusive-OR-expression
96 ///         logical-AND-expression '&&' inclusive-OR-expression
97 ///
98 ///       logical-OR-expression: [C99 6.5.14]
99 ///         logical-AND-expression
100 ///         logical-OR-expression '||' logical-AND-expression
101 ///
102 ///       conditional-expression: [C99 6.5.15]
103 ///         logical-OR-expression
104 ///         logical-OR-expression '?' expression ':' conditional-expression
105 /// [GNU]   logical-OR-expression '?' ':' conditional-expression
106 /// [C++] the third operand is an assignment-expression
107 ///
108 ///       assignment-expression: [C99 6.5.16]
109 ///         conditional-expression
110 ///         unary-expression assignment-operator assignment-expression
111 /// [C++]   throw-expression [C++ 15]
112 ///
113 ///       assignment-operator: one of
114 ///         = *= /= %= += -= <<= >>= &= ^= |=
115 ///
116 ///       expression: [C99 6.5.17]
117 ///         assignment-expression ...[opt]
118 ///         expression ',' assignment-expression ...[opt]
119 /// \endverbatim
ParseExpression(TypeCastState isTypeCast)120 ExprResult Parser::ParseExpression(TypeCastState isTypeCast) {
121   ExprResult LHS(ParseAssignmentExpression(isTypeCast));
122   return ParseRHSOfBinaryExpression(LHS, prec::Comma);
123 }
124 
125 /// This routine is called when the '@' is seen and consumed.
126 /// Current token is an Identifier and is not a 'try'. This
127 /// routine is necessary to disambiguate \@try-statement from,
128 /// for example, \@encode-expression.
129 ///
130 ExprResult
ParseExpressionWithLeadingAt(SourceLocation AtLoc)131 Parser::ParseExpressionWithLeadingAt(SourceLocation AtLoc) {
132   ExprResult LHS(ParseObjCAtExpression(AtLoc));
133   return ParseRHSOfBinaryExpression(LHS, prec::Comma);
134 }
135 
136 /// This routine is called when a leading '__extension__' is seen and
137 /// consumed.  This is necessary because the token gets consumed in the
138 /// process of disambiguating between an expression and a declaration.
139 ExprResult
ParseExpressionWithLeadingExtension(SourceLocation ExtLoc)140 Parser::ParseExpressionWithLeadingExtension(SourceLocation ExtLoc) {
141   ExprResult LHS(true);
142   {
143     // Silence extension warnings in the sub-expression
144     ExtensionRAIIObject O(Diags);
145 
146     LHS = ParseCastExpression(false);
147   }
148 
149   if (!LHS.isInvalid())
150     LHS = Actions.ActOnUnaryOp(getCurScope(), ExtLoc, tok::kw___extension__,
151                                LHS.get());
152 
153   return ParseRHSOfBinaryExpression(LHS, prec::Comma);
154 }
155 
156 /// \brief Parse an expr that doesn't include (top-level) commas.
ParseAssignmentExpression(TypeCastState isTypeCast)157 ExprResult Parser::ParseAssignmentExpression(TypeCastState isTypeCast) {
158   if (Tok.is(tok::code_completion)) {
159     Actions.CodeCompleteOrdinaryName(getCurScope(), Sema::PCC_Expression);
160     cutOffParsing();
161     return ExprError();
162   }
163 
164   if (Tok.is(tok::kw_throw))
165     return ParseThrowExpression();
166   if (Tok.is(tok::kw_co_yield))
167     return ParseCoyieldExpression();
168 
169   ExprResult LHS = ParseCastExpression(/*isUnaryExpression=*/false,
170                                        /*isAddressOfOperand=*/false,
171                                        isTypeCast);
172   return ParseRHSOfBinaryExpression(LHS, prec::Assignment);
173 }
174 
175 /// \brief Parse an assignment expression where part of an Objective-C message
176 /// send has already been parsed.
177 ///
178 /// In this case \p LBracLoc indicates the location of the '[' of the message
179 /// send, and either \p ReceiverName or \p ReceiverExpr is non-null indicating
180 /// the receiver of the message.
181 ///
182 /// Since this handles full assignment-expression's, it handles postfix
183 /// expressions and other binary operators for these expressions as well.
184 ExprResult
ParseAssignmentExprWithObjCMessageExprStart(SourceLocation LBracLoc,SourceLocation SuperLoc,ParsedType ReceiverType,Expr * ReceiverExpr)185 Parser::ParseAssignmentExprWithObjCMessageExprStart(SourceLocation LBracLoc,
186                                                     SourceLocation SuperLoc,
187                                                     ParsedType ReceiverType,
188                                                     Expr *ReceiverExpr) {
189   ExprResult R
190     = ParseObjCMessageExpressionBody(LBracLoc, SuperLoc,
191                                      ReceiverType, ReceiverExpr);
192   R = ParsePostfixExpressionSuffix(R);
193   return ParseRHSOfBinaryExpression(R, prec::Assignment);
194 }
195 
196 
ParseConstantExpression(TypeCastState isTypeCast)197 ExprResult Parser::ParseConstantExpression(TypeCastState isTypeCast) {
198   // C++03 [basic.def.odr]p2:
199   //   An expression is potentially evaluated unless it appears where an
200   //   integral constant expression is required (see 5.19) [...].
201   // C++98 and C++11 have no such rule, but this is only a defect in C++98.
202   EnterExpressionEvaluationContext Unevaluated(Actions,
203                                                Sema::ConstantEvaluated);
204 
205   ExprResult LHS(ParseCastExpression(false, false, isTypeCast));
206   ExprResult Res(ParseRHSOfBinaryExpression(LHS, prec::Conditional));
207   return Actions.ActOnConstantExpression(Res);
208 }
209 
210 /// \brief Parse a constraint-expression.
211 ///
212 /// \verbatim
213 ///       constraint-expression: [Concepts TS temp.constr.decl p1]
214 ///         logical-or-expression
215 /// \endverbatim
ParseConstraintExpression()216 ExprResult Parser::ParseConstraintExpression() {
217   // FIXME: this may erroneously consume a function-body as the braced
218   // initializer list of a compound literal
219   //
220   // FIXME: this may erroneously consume a parenthesized rvalue reference
221   // declarator as a parenthesized address-of-label expression
222   ExprResult LHS(ParseCastExpression(/*isUnaryExpression=*/false));
223   ExprResult Res(ParseRHSOfBinaryExpression(LHS, prec::LogicalOr));
224 
225   return Res;
226 }
227 
isNotExpressionStart()228 bool Parser::isNotExpressionStart() {
229   tok::TokenKind K = Tok.getKind();
230   if (K == tok::l_brace || K == tok::r_brace  ||
231       K == tok::kw_for  || K == tok::kw_while ||
232       K == tok::kw_if   || K == tok::kw_else  ||
233       K == tok::kw_goto || K == tok::kw_try)
234     return true;
235   // If this is a decl-specifier, we can't be at the start of an expression.
236   return isKnownToBeDeclarationSpecifier();
237 }
238 
isFoldOperator(prec::Level Level)239 static bool isFoldOperator(prec::Level Level) {
240   return Level > prec::Unknown && Level != prec::Conditional;
241 }
isFoldOperator(tok::TokenKind Kind)242 static bool isFoldOperator(tok::TokenKind Kind) {
243   return isFoldOperator(getBinOpPrecedence(Kind, false, true));
244 }
245 
246 /// \brief Parse a binary expression that starts with \p LHS and has a
247 /// precedence of at least \p MinPrec.
248 ExprResult
ParseRHSOfBinaryExpression(ExprResult LHS,prec::Level MinPrec)249 Parser::ParseRHSOfBinaryExpression(ExprResult LHS, prec::Level MinPrec) {
250   prec::Level NextTokPrec = getBinOpPrecedence(Tok.getKind(),
251                                                GreaterThanIsOperator,
252                                                getLangOpts().CPlusPlus11);
253   SourceLocation ColonLoc;
254 
255   while (1) {
256     // If this token has a lower precedence than we are allowed to parse (e.g.
257     // because we are called recursively, or because the token is not a binop),
258     // then we are done!
259     if (NextTokPrec < MinPrec)
260       return LHS;
261 
262     // Consume the operator, saving the operator token for error reporting.
263     Token OpToken = Tok;
264     ConsumeToken();
265 
266     // Bail out when encountering a comma followed by a token which can't
267     // possibly be the start of an expression. For instance:
268     //   int f() { return 1, }
269     // We can't do this before consuming the comma, because
270     // isNotExpressionStart() looks at the token stream.
271     if (OpToken.is(tok::comma) && isNotExpressionStart()) {
272       PP.EnterToken(Tok);
273       Tok = OpToken;
274       return LHS;
275     }
276 
277     // If the next token is an ellipsis, then this is a fold-expression. Leave
278     // it alone so we can handle it in the paren expression.
279     if (isFoldOperator(NextTokPrec) && Tok.is(tok::ellipsis)) {
280       // FIXME: We can't check this via lookahead before we consume the token
281       // because that tickles a lexer bug.
282       PP.EnterToken(Tok);
283       Tok = OpToken;
284       return LHS;
285     }
286 
287     // Special case handling for the ternary operator.
288     ExprResult TernaryMiddle(true);
289     if (NextTokPrec == prec::Conditional) {
290       if (Tok.isNot(tok::colon)) {
291         // Don't parse FOO:BAR as if it were a typo for FOO::BAR.
292         ColonProtectionRAIIObject X(*this);
293 
294         // Handle this production specially:
295         //   logical-OR-expression '?' expression ':' conditional-expression
296         // In particular, the RHS of the '?' is 'expression', not
297         // 'logical-OR-expression' as we might expect.
298         TernaryMiddle = ParseExpression();
299         if (TernaryMiddle.isInvalid()) {
300           Actions.CorrectDelayedTyposInExpr(LHS);
301           LHS = ExprError();
302           TernaryMiddle = nullptr;
303         }
304       } else {
305         // Special case handling of "X ? Y : Z" where Y is empty:
306         //   logical-OR-expression '?' ':' conditional-expression   [GNU]
307         TernaryMiddle = nullptr;
308         Diag(Tok, diag::ext_gnu_conditional_expr);
309       }
310 
311       if (!TryConsumeToken(tok::colon, ColonLoc)) {
312         // Otherwise, we're missing a ':'.  Assume that this was a typo that
313         // the user forgot. If we're not in a macro expansion, we can suggest
314         // a fixit hint. If there were two spaces before the current token,
315         // suggest inserting the colon in between them, otherwise insert ": ".
316         SourceLocation FILoc = Tok.getLocation();
317         const char *FIText = ": ";
318         const SourceManager &SM = PP.getSourceManager();
319         if (FILoc.isFileID() || PP.isAtStartOfMacroExpansion(FILoc, &FILoc)) {
320           assert(FILoc.isFileID());
321           bool IsInvalid = false;
322           const char *SourcePtr =
323             SM.getCharacterData(FILoc.getLocWithOffset(-1), &IsInvalid);
324           if (!IsInvalid && *SourcePtr == ' ') {
325             SourcePtr =
326               SM.getCharacterData(FILoc.getLocWithOffset(-2), &IsInvalid);
327             if (!IsInvalid && *SourcePtr == ' ') {
328               FILoc = FILoc.getLocWithOffset(-1);
329               FIText = ":";
330             }
331           }
332         }
333 
334         Diag(Tok, diag::err_expected)
335             << tok::colon << FixItHint::CreateInsertion(FILoc, FIText);
336         Diag(OpToken, diag::note_matching) << tok::question;
337         ColonLoc = Tok.getLocation();
338       }
339     }
340 
341     // Code completion for the right-hand side of an assignment expression
342     // goes through a special hook that takes the left-hand side into account.
343     if (Tok.is(tok::code_completion) && NextTokPrec == prec::Assignment) {
344       Actions.CodeCompleteAssignmentRHS(getCurScope(), LHS.get());
345       cutOffParsing();
346       return ExprError();
347     }
348 
349     // Parse another leaf here for the RHS of the operator.
350     // ParseCastExpression works here because all RHS expressions in C have it
351     // as a prefix, at least. However, in C++, an assignment-expression could
352     // be a throw-expression, which is not a valid cast-expression.
353     // Therefore we need some special-casing here.
354     // Also note that the third operand of the conditional operator is
355     // an assignment-expression in C++, and in C++11, we can have a
356     // braced-init-list on the RHS of an assignment. For better diagnostics,
357     // parse as if we were allowed braced-init-lists everywhere, and check that
358     // they only appear on the RHS of assignments later.
359     ExprResult RHS;
360     bool RHSIsInitList = false;
361     if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
362       RHS = ParseBraceInitializer();
363       RHSIsInitList = true;
364     } else if (getLangOpts().CPlusPlus && NextTokPrec <= prec::Conditional)
365       RHS = ParseAssignmentExpression();
366     else
367       RHS = ParseCastExpression(false);
368 
369     if (RHS.isInvalid()) {
370       // FIXME: Errors generated by the delayed typo correction should be
371       // printed before errors from parsing the RHS, not after.
372       Actions.CorrectDelayedTyposInExpr(LHS);
373       if (TernaryMiddle.isUsable())
374         TernaryMiddle = Actions.CorrectDelayedTyposInExpr(TernaryMiddle);
375       LHS = ExprError();
376     }
377 
378     // Remember the precedence of this operator and get the precedence of the
379     // operator immediately to the right of the RHS.
380     prec::Level ThisPrec = NextTokPrec;
381     NextTokPrec = getBinOpPrecedence(Tok.getKind(), GreaterThanIsOperator,
382                                      getLangOpts().CPlusPlus11);
383 
384     // Assignment and conditional expressions are right-associative.
385     bool isRightAssoc = ThisPrec == prec::Conditional ||
386                         ThisPrec == prec::Assignment;
387 
388     // Get the precedence of the operator to the right of the RHS.  If it binds
389     // more tightly with RHS than we do, evaluate it completely first.
390     if (ThisPrec < NextTokPrec ||
391         (ThisPrec == NextTokPrec && isRightAssoc)) {
392       if (!RHS.isInvalid() && RHSIsInitList) {
393         Diag(Tok, diag::err_init_list_bin_op)
394           << /*LHS*/0 << PP.getSpelling(Tok) << Actions.getExprRange(RHS.get());
395         RHS = ExprError();
396       }
397       // If this is left-associative, only parse things on the RHS that bind
398       // more tightly than the current operator.  If it is left-associative, it
399       // is okay, to bind exactly as tightly.  For example, compile A=B=C=D as
400       // A=(B=(C=D)), where each paren is a level of recursion here.
401       // The function takes ownership of the RHS.
402       RHS = ParseRHSOfBinaryExpression(RHS,
403                             static_cast<prec::Level>(ThisPrec + !isRightAssoc));
404       RHSIsInitList = false;
405 
406       if (RHS.isInvalid()) {
407         // FIXME: Errors generated by the delayed typo correction should be
408         // printed before errors from ParseRHSOfBinaryExpression, not after.
409         Actions.CorrectDelayedTyposInExpr(LHS);
410         if (TernaryMiddle.isUsable())
411           TernaryMiddle = Actions.CorrectDelayedTyposInExpr(TernaryMiddle);
412         LHS = ExprError();
413       }
414 
415       NextTokPrec = getBinOpPrecedence(Tok.getKind(), GreaterThanIsOperator,
416                                        getLangOpts().CPlusPlus11);
417     }
418 
419     if (!RHS.isInvalid() && RHSIsInitList) {
420       if (ThisPrec == prec::Assignment) {
421         Diag(OpToken, diag::warn_cxx98_compat_generalized_initializer_lists)
422           << Actions.getExprRange(RHS.get());
423       } else {
424         Diag(OpToken, diag::err_init_list_bin_op)
425           << /*RHS*/1 << PP.getSpelling(OpToken)
426           << Actions.getExprRange(RHS.get());
427         LHS = ExprError();
428       }
429     }
430 
431     if (!LHS.isInvalid()) {
432       // Combine the LHS and RHS into the LHS (e.g. build AST).
433       if (TernaryMiddle.isInvalid()) {
434         // If we're using '>>' as an operator within a template
435         // argument list (in C++98), suggest the addition of
436         // parentheses so that the code remains well-formed in C++0x.
437         if (!GreaterThanIsOperator && OpToken.is(tok::greatergreater))
438           SuggestParentheses(OpToken.getLocation(),
439                              diag::warn_cxx11_right_shift_in_template_arg,
440                          SourceRange(Actions.getExprRange(LHS.get()).getBegin(),
441                                      Actions.getExprRange(RHS.get()).getEnd()));
442 
443         LHS = Actions.ActOnBinOp(getCurScope(), OpToken.getLocation(),
444                                  OpToken.getKind(), LHS.get(), RHS.get());
445       } else
446         LHS = Actions.ActOnConditionalOp(OpToken.getLocation(), ColonLoc,
447                                          LHS.get(), TernaryMiddle.get(),
448                                          RHS.get());
449     } else
450       // Ensure potential typos in the RHS aren't left undiagnosed.
451       Actions.CorrectDelayedTyposInExpr(RHS);
452   }
453 }
454 
455 /// \brief Parse a cast-expression, or, if \p isUnaryExpression is true,
456 /// parse a unary-expression.
457 ///
458 /// \p isAddressOfOperand exists because an id-expression that is the
459 /// operand of address-of gets special treatment due to member pointers.
460 ///
ParseCastExpression(bool isUnaryExpression,bool isAddressOfOperand,TypeCastState isTypeCast)461 ExprResult Parser::ParseCastExpression(bool isUnaryExpression,
462                                        bool isAddressOfOperand,
463                                        TypeCastState isTypeCast) {
464   bool NotCastExpr;
465   ExprResult Res = ParseCastExpression(isUnaryExpression,
466                                        isAddressOfOperand,
467                                        NotCastExpr,
468                                        isTypeCast);
469   if (NotCastExpr)
470     Diag(Tok, diag::err_expected_expression);
471   return Res;
472 }
473 
474 namespace {
475 class CastExpressionIdValidator : public CorrectionCandidateCallback {
476  public:
CastExpressionIdValidator(Token Next,bool AllowTypes,bool AllowNonTypes)477   CastExpressionIdValidator(Token Next, bool AllowTypes, bool AllowNonTypes)
478       : NextToken(Next), AllowNonTypes(AllowNonTypes) {
479     WantTypeSpecifiers = WantFunctionLikeCasts = AllowTypes;
480   }
481 
ValidateCandidate(const TypoCorrection & candidate)482   bool ValidateCandidate(const TypoCorrection &candidate) override {
483     NamedDecl *ND = candidate.getCorrectionDecl();
484     if (!ND)
485       return candidate.isKeyword();
486 
487     if (isa<TypeDecl>(ND))
488       return WantTypeSpecifiers;
489 
490     if (!AllowNonTypes || !CorrectionCandidateCallback::ValidateCandidate(candidate))
491       return false;
492 
493     if (!NextToken.isOneOf(tok::equal, tok::arrow, tok::period))
494       return true;
495 
496     for (auto *C : candidate) {
497       NamedDecl *ND = C->getUnderlyingDecl();
498       if (isa<ValueDecl>(ND) && !isa<FunctionDecl>(ND))
499         return true;
500     }
501     return false;
502   }
503 
504  private:
505   Token NextToken;
506   bool AllowNonTypes;
507 };
508 }
509 
510 /// \brief Parse a cast-expression, or, if \pisUnaryExpression is true, parse
511 /// a unary-expression.
512 ///
513 /// \p isAddressOfOperand exists because an id-expression that is the operand
514 /// of address-of gets special treatment due to member pointers. NotCastExpr
515 /// is set to true if the token is not the start of a cast-expression, and no
516 /// diagnostic is emitted in this case.
517 ///
518 /// \verbatim
519 ///       cast-expression: [C99 6.5.4]
520 ///         unary-expression
521 ///         '(' type-name ')' cast-expression
522 ///
523 ///       unary-expression:  [C99 6.5.3]
524 ///         postfix-expression
525 ///         '++' unary-expression
526 ///         '--' unary-expression
527 /// [Coro]  'co_await' cast-expression
528 ///         unary-operator cast-expression
529 ///         'sizeof' unary-expression
530 ///         'sizeof' '(' type-name ')'
531 /// [C++11] 'sizeof' '...' '(' identifier ')'
532 /// [GNU]   '__alignof' unary-expression
533 /// [GNU]   '__alignof' '(' type-name ')'
534 /// [C11]   '_Alignof' '(' type-name ')'
535 /// [C++11] 'alignof' '(' type-id ')'
536 /// [GNU]   '&&' identifier
537 /// [C++11] 'noexcept' '(' expression ')' [C++11 5.3.7]
538 /// [C++]   new-expression
539 /// [C++]   delete-expression
540 ///
541 ///       unary-operator: one of
542 ///         '&'  '*'  '+'  '-'  '~'  '!'
543 /// [GNU]   '__extension__'  '__real'  '__imag'
544 ///
545 ///       primary-expression: [C99 6.5.1]
546 /// [C99]   identifier
547 /// [C++]   id-expression
548 ///         constant
549 ///         string-literal
550 /// [C++]   boolean-literal  [C++ 2.13.5]
551 /// [C++11] 'nullptr'        [C++11 2.14.7]
552 /// [C++11] user-defined-literal
553 ///         '(' expression ')'
554 /// [C11]   generic-selection
555 ///         '__func__'        [C99 6.4.2.2]
556 /// [GNU]   '__FUNCTION__'
557 /// [MS]    '__FUNCDNAME__'
558 /// [MS]    'L__FUNCTION__'
559 /// [GNU]   '__PRETTY_FUNCTION__'
560 /// [GNU]   '(' compound-statement ')'
561 /// [GNU]   '__builtin_va_arg' '(' assignment-expression ',' type-name ')'
562 /// [GNU]   '__builtin_offsetof' '(' type-name ',' offsetof-member-designator')'
563 /// [GNU]   '__builtin_choose_expr' '(' assign-expr ',' assign-expr ','
564 ///                                     assign-expr ')'
565 /// [GNU]   '__builtin_types_compatible_p' '(' type-name ',' type-name ')'
566 /// [GNU]   '__null'
567 /// [OBJC]  '[' objc-message-expr ']'
568 /// [OBJC]  '\@selector' '(' objc-selector-arg ')'
569 /// [OBJC]  '\@protocol' '(' identifier ')'
570 /// [OBJC]  '\@encode' '(' type-name ')'
571 /// [OBJC]  objc-string-literal
572 /// [C++]   simple-type-specifier '(' expression-list[opt] ')'      [C++ 5.2.3]
573 /// [C++11] simple-type-specifier braced-init-list                  [C++11 5.2.3]
574 /// [C++]   typename-specifier '(' expression-list[opt] ')'         [C++ 5.2.3]
575 /// [C++11] typename-specifier braced-init-list                     [C++11 5.2.3]
576 /// [C++]   'const_cast' '<' type-name '>' '(' expression ')'       [C++ 5.2p1]
577 /// [C++]   'dynamic_cast' '<' type-name '>' '(' expression ')'     [C++ 5.2p1]
578 /// [C++]   'reinterpret_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
579 /// [C++]   'static_cast' '<' type-name '>' '(' expression ')'      [C++ 5.2p1]
580 /// [C++]   'typeid' '(' expression ')'                             [C++ 5.2p1]
581 /// [C++]   'typeid' '(' type-id ')'                                [C++ 5.2p1]
582 /// [C++]   'this'          [C++ 9.3.2]
583 /// [G++]   unary-type-trait '(' type-id ')'
584 /// [G++]   binary-type-trait '(' type-id ',' type-id ')'           [TODO]
585 /// [EMBT]  array-type-trait '(' type-id ',' integer ')'
586 /// [clang] '^' block-literal
587 ///
588 ///       constant: [C99 6.4.4]
589 ///         integer-constant
590 ///         floating-constant
591 ///         enumeration-constant -> identifier
592 ///         character-constant
593 ///
594 ///       id-expression: [C++ 5.1]
595 ///                   unqualified-id
596 ///                   qualified-id
597 ///
598 ///       unqualified-id: [C++ 5.1]
599 ///                   identifier
600 ///                   operator-function-id
601 ///                   conversion-function-id
602 ///                   '~' class-name
603 ///                   template-id
604 ///
605 ///       new-expression: [C++ 5.3.4]
606 ///                   '::'[opt] 'new' new-placement[opt] new-type-id
607 ///                                     new-initializer[opt]
608 ///                   '::'[opt] 'new' new-placement[opt] '(' type-id ')'
609 ///                                     new-initializer[opt]
610 ///
611 ///       delete-expression: [C++ 5.3.5]
612 ///                   '::'[opt] 'delete' cast-expression
613 ///                   '::'[opt] 'delete' '[' ']' cast-expression
614 ///
615 /// [GNU/Embarcadero] unary-type-trait:
616 ///                   '__is_arithmetic'
617 ///                   '__is_floating_point'
618 ///                   '__is_integral'
619 ///                   '__is_lvalue_expr'
620 ///                   '__is_rvalue_expr'
621 ///                   '__is_complete_type'
622 ///                   '__is_void'
623 ///                   '__is_array'
624 ///                   '__is_function'
625 ///                   '__is_reference'
626 ///                   '__is_lvalue_reference'
627 ///                   '__is_rvalue_reference'
628 ///                   '__is_fundamental'
629 ///                   '__is_object'
630 ///                   '__is_scalar'
631 ///                   '__is_compound'
632 ///                   '__is_pointer'
633 ///                   '__is_member_object_pointer'
634 ///                   '__is_member_function_pointer'
635 ///                   '__is_member_pointer'
636 ///                   '__is_const'
637 ///                   '__is_volatile'
638 ///                   '__is_trivial'
639 ///                   '__is_standard_layout'
640 ///                   '__is_signed'
641 ///                   '__is_unsigned'
642 ///
643 /// [GNU] unary-type-trait:
644 ///                   '__has_nothrow_assign'
645 ///                   '__has_nothrow_copy'
646 ///                   '__has_nothrow_constructor'
647 ///                   '__has_trivial_assign'                  [TODO]
648 ///                   '__has_trivial_copy'                    [TODO]
649 ///                   '__has_trivial_constructor'
650 ///                   '__has_trivial_destructor'
651 ///                   '__has_virtual_destructor'
652 ///                   '__is_abstract'                         [TODO]
653 ///                   '__is_class'
654 ///                   '__is_empty'                            [TODO]
655 ///                   '__is_enum'
656 ///                   '__is_final'
657 ///                   '__is_pod'
658 ///                   '__is_polymorphic'
659 ///                   '__is_sealed'                           [MS]
660 ///                   '__is_trivial'
661 ///                   '__is_union'
662 ///
663 /// [Clang] unary-type-trait:
664 ///                   '__trivially_copyable'
665 ///
666 ///       binary-type-trait:
667 /// [GNU]             '__is_base_of'
668 /// [MS]              '__is_convertible_to'
669 ///                   '__is_convertible'
670 ///                   '__is_same'
671 ///
672 /// [Embarcadero] array-type-trait:
673 ///                   '__array_rank'
674 ///                   '__array_extent'
675 ///
676 /// [Embarcadero] expression-trait:
677 ///                   '__is_lvalue_expr'
678 ///                   '__is_rvalue_expr'
679 /// \endverbatim
680 ///
ParseCastExpression(bool isUnaryExpression,bool isAddressOfOperand,bool & NotCastExpr,TypeCastState isTypeCast)681 ExprResult Parser::ParseCastExpression(bool isUnaryExpression,
682                                        bool isAddressOfOperand,
683                                        bool &NotCastExpr,
684                                        TypeCastState isTypeCast) {
685   ExprResult Res;
686   tok::TokenKind SavedKind = Tok.getKind();
687   NotCastExpr = false;
688 
689   // This handles all of cast-expression, unary-expression, postfix-expression,
690   // and primary-expression.  We handle them together like this for efficiency
691   // and to simplify handling of an expression starting with a '(' token: which
692   // may be one of a parenthesized expression, cast-expression, compound literal
693   // expression, or statement expression.
694   //
695   // If the parsed tokens consist of a primary-expression, the cases below
696   // break out of the switch;  at the end we call ParsePostfixExpressionSuffix
697   // to handle the postfix expression suffixes.  Cases that cannot be followed
698   // by postfix exprs should return without invoking
699   // ParsePostfixExpressionSuffix.
700   switch (SavedKind) {
701   case tok::l_paren: {
702     // If this expression is limited to being a unary-expression, the parent can
703     // not start a cast expression.
704     ParenParseOption ParenExprType =
705         (isUnaryExpression && !getLangOpts().CPlusPlus) ? CompoundLiteral
706                                                         : CastExpr;
707     ParsedType CastTy;
708     SourceLocation RParenLoc;
709     Res = ParseParenExpression(ParenExprType, false/*stopIfCastExr*/,
710                                isTypeCast == IsTypeCast, CastTy, RParenLoc);
711 
712     switch (ParenExprType) {
713     case SimpleExpr:   break;    // Nothing else to do.
714     case CompoundStmt: break;  // Nothing else to do.
715     case CompoundLiteral:
716       // We parsed '(' type-name ')' '{' ... '}'.  If any suffixes of
717       // postfix-expression exist, parse them now.
718       break;
719     case CastExpr:
720       // We have parsed the cast-expression and no postfix-expr pieces are
721       // following.
722       return Res;
723     }
724 
725     break;
726   }
727 
728     // primary-expression
729   case tok::numeric_constant:
730     // constant: integer-constant
731     // constant: floating-constant
732 
733     Res = Actions.ActOnNumericConstant(Tok, /*UDLScope*/getCurScope());
734     ConsumeToken();
735     break;
736 
737   case tok::kw_true:
738   case tok::kw_false:
739     return ParseCXXBoolLiteral();
740 
741   case tok::kw___objc_yes:
742   case tok::kw___objc_no:
743       return ParseObjCBoolLiteral();
744 
745   case tok::kw_nullptr:
746     Diag(Tok, diag::warn_cxx98_compat_nullptr);
747     return Actions.ActOnCXXNullPtrLiteral(ConsumeToken());
748 
749   case tok::annot_primary_expr:
750     assert(Res.get() == nullptr && "Stray primary-expression annotation?");
751     Res = getExprAnnotation(Tok);
752     ConsumeToken();
753     break;
754 
755   case tok::kw___super:
756   case tok::kw_decltype:
757     // Annotate the token and tail recurse.
758     if (TryAnnotateTypeOrScopeToken())
759       return ExprError();
760     assert(Tok.isNot(tok::kw_decltype) && Tok.isNot(tok::kw___super));
761     return ParseCastExpression(isUnaryExpression, isAddressOfOperand);
762 
763   case tok::identifier: {      // primary-expression: identifier
764                                // unqualified-id: identifier
765                                // constant: enumeration-constant
766     // Turn a potentially qualified name into a annot_typename or
767     // annot_cxxscope if it would be valid.  This handles things like x::y, etc.
768     if (getLangOpts().CPlusPlus) {
769       // Avoid the unnecessary parse-time lookup in the common case
770       // where the syntax forbids a type.
771       const Token &Next = NextToken();
772 
773       // If this identifier was reverted from a token ID, and the next token
774       // is a parenthesis, this is likely to be a use of a type trait. Check
775       // those tokens.
776       if (Next.is(tok::l_paren) &&
777           Tok.is(tok::identifier) &&
778           Tok.getIdentifierInfo()->hasRevertedTokenIDToIdentifier()) {
779         IdentifierInfo *II = Tok.getIdentifierInfo();
780         // Build up the mapping of revertible type traits, for future use.
781         if (RevertibleTypeTraits.empty()) {
782 #define RTT_JOIN(X,Y) X##Y
783 #define REVERTIBLE_TYPE_TRAIT(Name)                         \
784           RevertibleTypeTraits[PP.getIdentifierInfo(#Name)] \
785             = RTT_JOIN(tok::kw_,Name)
786 
787           REVERTIBLE_TYPE_TRAIT(__is_abstract);
788           REVERTIBLE_TYPE_TRAIT(__is_arithmetic);
789           REVERTIBLE_TYPE_TRAIT(__is_array);
790           REVERTIBLE_TYPE_TRAIT(__is_base_of);
791           REVERTIBLE_TYPE_TRAIT(__is_class);
792           REVERTIBLE_TYPE_TRAIT(__is_complete_type);
793           REVERTIBLE_TYPE_TRAIT(__is_compound);
794           REVERTIBLE_TYPE_TRAIT(__is_const);
795           REVERTIBLE_TYPE_TRAIT(__is_constructible);
796           REVERTIBLE_TYPE_TRAIT(__is_convertible);
797           REVERTIBLE_TYPE_TRAIT(__is_convertible_to);
798           REVERTIBLE_TYPE_TRAIT(__is_destructible);
799           REVERTIBLE_TYPE_TRAIT(__is_empty);
800           REVERTIBLE_TYPE_TRAIT(__is_enum);
801           REVERTIBLE_TYPE_TRAIT(__is_floating_point);
802           REVERTIBLE_TYPE_TRAIT(__is_final);
803           REVERTIBLE_TYPE_TRAIT(__is_function);
804           REVERTIBLE_TYPE_TRAIT(__is_fundamental);
805           REVERTIBLE_TYPE_TRAIT(__is_integral);
806           REVERTIBLE_TYPE_TRAIT(__is_interface_class);
807           REVERTIBLE_TYPE_TRAIT(__is_literal);
808           REVERTIBLE_TYPE_TRAIT(__is_lvalue_expr);
809           REVERTIBLE_TYPE_TRAIT(__is_lvalue_reference);
810           REVERTIBLE_TYPE_TRAIT(__is_member_function_pointer);
811           REVERTIBLE_TYPE_TRAIT(__is_member_object_pointer);
812           REVERTIBLE_TYPE_TRAIT(__is_member_pointer);
813           REVERTIBLE_TYPE_TRAIT(__is_nothrow_assignable);
814           REVERTIBLE_TYPE_TRAIT(__is_nothrow_constructible);
815           REVERTIBLE_TYPE_TRAIT(__is_nothrow_destructible);
816           REVERTIBLE_TYPE_TRAIT(__is_object);
817           REVERTIBLE_TYPE_TRAIT(__is_pod);
818           REVERTIBLE_TYPE_TRAIT(__is_pointer);
819           REVERTIBLE_TYPE_TRAIT(__is_polymorphic);
820           REVERTIBLE_TYPE_TRAIT(__is_reference);
821           REVERTIBLE_TYPE_TRAIT(__is_rvalue_expr);
822           REVERTIBLE_TYPE_TRAIT(__is_rvalue_reference);
823           REVERTIBLE_TYPE_TRAIT(__is_same);
824           REVERTIBLE_TYPE_TRAIT(__is_scalar);
825           REVERTIBLE_TYPE_TRAIT(__is_sealed);
826           REVERTIBLE_TYPE_TRAIT(__is_signed);
827           REVERTIBLE_TYPE_TRAIT(__is_standard_layout);
828           REVERTIBLE_TYPE_TRAIT(__is_trivial);
829           REVERTIBLE_TYPE_TRAIT(__is_trivially_assignable);
830           REVERTIBLE_TYPE_TRAIT(__is_trivially_constructible);
831           REVERTIBLE_TYPE_TRAIT(__is_trivially_copyable);
832           REVERTIBLE_TYPE_TRAIT(__is_union);
833           REVERTIBLE_TYPE_TRAIT(__is_unsigned);
834           REVERTIBLE_TYPE_TRAIT(__is_void);
835           REVERTIBLE_TYPE_TRAIT(__is_volatile);
836 #undef REVERTIBLE_TYPE_TRAIT
837 #undef RTT_JOIN
838         }
839 
840         // If we find that this is in fact the name of a type trait,
841         // update the token kind in place and parse again to treat it as
842         // the appropriate kind of type trait.
843         llvm::SmallDenseMap<IdentifierInfo *, tok::TokenKind>::iterator Known
844           = RevertibleTypeTraits.find(II);
845         if (Known != RevertibleTypeTraits.end()) {
846           Tok.setKind(Known->second);
847           return ParseCastExpression(isUnaryExpression, isAddressOfOperand,
848                                      NotCastExpr, isTypeCast);
849         }
850       }
851 
852       if ((!ColonIsSacred && Next.is(tok::colon)) ||
853           Next.isOneOf(tok::coloncolon, tok::less, tok::l_paren,
854                        tok::l_brace)) {
855         // If TryAnnotateTypeOrScopeToken annotates the token, tail recurse.
856         if (TryAnnotateTypeOrScopeToken())
857           return ExprError();
858         if (!Tok.is(tok::identifier))
859           return ParseCastExpression(isUnaryExpression, isAddressOfOperand);
860       }
861     }
862 
863     // Consume the identifier so that we can see if it is followed by a '(' or
864     // '.'.
865     IdentifierInfo &II = *Tok.getIdentifierInfo();
866     SourceLocation ILoc = ConsumeToken();
867 
868     // Support 'Class.property' and 'super.property' notation.
869     if (getLangOpts().ObjC1 && Tok.is(tok::period) &&
870         (Actions.getTypeName(II, ILoc, getCurScope()) ||
871          // Allow the base to be 'super' if in an objc-method.
872          (&II == Ident_super && getCurScope()->isInObjcMethodScope()))) {
873       ConsumeToken();
874 
875       // Allow either an identifier or the keyword 'class' (in C++).
876       if (Tok.isNot(tok::identifier) &&
877           !(getLangOpts().CPlusPlus && Tok.is(tok::kw_class))) {
878         Diag(Tok, diag::err_expected_property_name);
879         return ExprError();
880       }
881       IdentifierInfo &PropertyName = *Tok.getIdentifierInfo();
882       SourceLocation PropertyLoc = ConsumeToken();
883 
884       Res = Actions.ActOnClassPropertyRefExpr(II, PropertyName,
885                                               ILoc, PropertyLoc);
886       break;
887     }
888 
889     // In an Objective-C method, if we have "super" followed by an identifier,
890     // the token sequence is ill-formed. However, if there's a ':' or ']' after
891     // that identifier, this is probably a message send with a missing open
892     // bracket. Treat it as such.
893     if (getLangOpts().ObjC1 && &II == Ident_super && !InMessageExpression &&
894         getCurScope()->isInObjcMethodScope() &&
895         ((Tok.is(tok::identifier) &&
896          (NextToken().is(tok::colon) || NextToken().is(tok::r_square))) ||
897          Tok.is(tok::code_completion))) {
898       Res = ParseObjCMessageExpressionBody(SourceLocation(), ILoc, ParsedType(),
899                                            nullptr);
900       break;
901     }
902 
903     // If we have an Objective-C class name followed by an identifier
904     // and either ':' or ']', this is an Objective-C class message
905     // send that's missing the opening '['. Recovery
906     // appropriately. Also take this path if we're performing code
907     // completion after an Objective-C class name.
908     if (getLangOpts().ObjC1 &&
909         ((Tok.is(tok::identifier) && !InMessageExpression) ||
910          Tok.is(tok::code_completion))) {
911       const Token& Next = NextToken();
912       if (Tok.is(tok::code_completion) ||
913           Next.is(tok::colon) || Next.is(tok::r_square))
914         if (ParsedType Typ = Actions.getTypeName(II, ILoc, getCurScope()))
915           if (Typ.get()->isObjCObjectOrInterfaceType()) {
916             // Fake up a Declarator to use with ActOnTypeName.
917             DeclSpec DS(AttrFactory);
918             DS.SetRangeStart(ILoc);
919             DS.SetRangeEnd(ILoc);
920             const char *PrevSpec = nullptr;
921             unsigned DiagID;
922             DS.SetTypeSpecType(TST_typename, ILoc, PrevSpec, DiagID, Typ,
923                                Actions.getASTContext().getPrintingPolicy());
924 
925             Declarator DeclaratorInfo(DS, Declarator::TypeNameContext);
926             TypeResult Ty = Actions.ActOnTypeName(getCurScope(),
927                                                   DeclaratorInfo);
928             if (Ty.isInvalid())
929               break;
930 
931             Res = ParseObjCMessageExpressionBody(SourceLocation(),
932                                                  SourceLocation(),
933                                                  Ty.get(), nullptr);
934             break;
935           }
936     }
937 
938     // Make sure to pass down the right value for isAddressOfOperand.
939     if (isAddressOfOperand && isPostfixExpressionSuffixStart())
940       isAddressOfOperand = false;
941 
942     // Function designators are allowed to be undeclared (C99 6.5.1p2), so we
943     // need to know whether or not this identifier is a function designator or
944     // not.
945     UnqualifiedId Name;
946     CXXScopeSpec ScopeSpec;
947     SourceLocation TemplateKWLoc;
948     Token Replacement;
949     auto Validator = llvm::make_unique<CastExpressionIdValidator>(
950         Tok, isTypeCast != NotTypeCast, isTypeCast != IsTypeCast);
951     Validator->IsAddressOfOperand = isAddressOfOperand;
952     if (Tok.isOneOf(tok::periodstar, tok::arrowstar)) {
953       Validator->WantExpressionKeywords = false;
954       Validator->WantRemainingKeywords = false;
955     } else {
956       Validator->WantRemainingKeywords = Tok.isNot(tok::r_paren);
957     }
958     Name.setIdentifier(&II, ILoc);
959     Res = Actions.ActOnIdExpression(
960         getCurScope(), ScopeSpec, TemplateKWLoc, Name, Tok.is(tok::l_paren),
961         isAddressOfOperand, std::move(Validator),
962         /*IsInlineAsmIdentifier=*/false,
963         Tok.is(tok::r_paren) ? nullptr : &Replacement);
964     if (!Res.isInvalid() && !Res.get()) {
965       UnconsumeToken(Replacement);
966       return ParseCastExpression(isUnaryExpression, isAddressOfOperand,
967                                  NotCastExpr, isTypeCast);
968     }
969     break;
970   }
971   case tok::char_constant:     // constant: character-constant
972   case tok::wide_char_constant:
973   case tok::utf8_char_constant:
974   case tok::utf16_char_constant:
975   case tok::utf32_char_constant:
976     Res = Actions.ActOnCharacterConstant(Tok, /*UDLScope*/getCurScope());
977     ConsumeToken();
978     break;
979   case tok::kw___func__:       // primary-expression: __func__ [C99 6.4.2.2]
980   case tok::kw___FUNCTION__:   // primary-expression: __FUNCTION__ [GNU]
981   case tok::kw___FUNCDNAME__:   // primary-expression: __FUNCDNAME__ [MS]
982   case tok::kw___FUNCSIG__:     // primary-expression: __FUNCSIG__ [MS]
983   case tok::kw_L__FUNCTION__:   // primary-expression: L__FUNCTION__ [MS]
984   case tok::kw___PRETTY_FUNCTION__:  // primary-expression: __P..Y_F..N__ [GNU]
985     Res = Actions.ActOnPredefinedExpr(Tok.getLocation(), SavedKind);
986     ConsumeToken();
987     break;
988   case tok::string_literal:    // primary-expression: string-literal
989   case tok::wide_string_literal:
990   case tok::utf8_string_literal:
991   case tok::utf16_string_literal:
992   case tok::utf32_string_literal:
993     Res = ParseStringLiteralExpression(true);
994     break;
995   case tok::kw__Generic:   // primary-expression: generic-selection [C11 6.5.1]
996     Res = ParseGenericSelectionExpression();
997     break;
998   case tok::kw___builtin_va_arg:
999   case tok::kw___builtin_offsetof:
1000   case tok::kw___builtin_choose_expr:
1001   case tok::kw___builtin_astype: // primary-expression: [OCL] as_type()
1002   case tok::kw___builtin_convertvector:
1003     return ParseBuiltinPrimaryExpression();
1004   case tok::kw___null:
1005     return Actions.ActOnGNUNullExpr(ConsumeToken());
1006 
1007   case tok::plusplus:      // unary-expression: '++' unary-expression [C99]
1008   case tok::minusminus: {  // unary-expression: '--' unary-expression [C99]
1009     // C++ [expr.unary] has:
1010     //   unary-expression:
1011     //     ++ cast-expression
1012     //     -- cast-expression
1013     SourceLocation SavedLoc = ConsumeToken();
1014     // One special case is implicitly handled here: if the preceding tokens are
1015     // an ambiguous cast expression, such as "(T())++", then we recurse to
1016     // determine whether the '++' is prefix or postfix.
1017     Res = ParseCastExpression(!getLangOpts().CPlusPlus,
1018                               /*isAddressOfOperand*/false, NotCastExpr,
1019                               NotTypeCast);
1020     if (!Res.isInvalid())
1021       Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Res.get());
1022     return Res;
1023   }
1024   case tok::amp: {         // unary-expression: '&' cast-expression
1025     // Special treatment because of member pointers
1026     SourceLocation SavedLoc = ConsumeToken();
1027     Res = ParseCastExpression(false, true);
1028     if (!Res.isInvalid())
1029       Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Res.get());
1030     return Res;
1031   }
1032 
1033   case tok::star:          // unary-expression: '*' cast-expression
1034   case tok::plus:          // unary-expression: '+' cast-expression
1035   case tok::minus:         // unary-expression: '-' cast-expression
1036   case tok::tilde:         // unary-expression: '~' cast-expression
1037   case tok::exclaim:       // unary-expression: '!' cast-expression
1038   case tok::kw___real:     // unary-expression: '__real' cast-expression [GNU]
1039   case tok::kw___imag: {   // unary-expression: '__imag' cast-expression [GNU]
1040     SourceLocation SavedLoc = ConsumeToken();
1041     Res = ParseCastExpression(false);
1042     if (!Res.isInvalid())
1043       Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Res.get());
1044     return Res;
1045   }
1046 
1047   case tok::kw_co_await: {  // unary-expression: 'co_await' cast-expression
1048     SourceLocation CoawaitLoc = ConsumeToken();
1049     Res = ParseCastExpression(false);
1050     if (!Res.isInvalid())
1051       Res = Actions.ActOnCoawaitExpr(getCurScope(), CoawaitLoc, Res.get());
1052     return Res;
1053   }
1054 
1055   case tok::kw___extension__:{//unary-expression:'__extension__' cast-expr [GNU]
1056     // __extension__ silences extension warnings in the subexpression.
1057     ExtensionRAIIObject O(Diags);  // Use RAII to do this.
1058     SourceLocation SavedLoc = ConsumeToken();
1059     Res = ParseCastExpression(false);
1060     if (!Res.isInvalid())
1061       Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Res.get());
1062     return Res;
1063   }
1064   case tok::kw__Alignof:   // unary-expression: '_Alignof' '(' type-name ')'
1065     if (!getLangOpts().C11)
1066       Diag(Tok, diag::ext_c11_alignment) << Tok.getName();
1067     // fallthrough
1068   case tok::kw_alignof:    // unary-expression: 'alignof' '(' type-id ')'
1069   case tok::kw___alignof:  // unary-expression: '__alignof' unary-expression
1070                            // unary-expression: '__alignof' '(' type-name ')'
1071   case tok::kw_sizeof:     // unary-expression: 'sizeof' unary-expression
1072                            // unary-expression: 'sizeof' '(' type-name ')'
1073   case tok::kw_vec_step:   // unary-expression: OpenCL 'vec_step' expression
1074   // unary-expression: '__builtin_omp_required_simd_align' '(' type-name ')'
1075   case tok::kw___builtin_omp_required_simd_align:
1076     return ParseUnaryExprOrTypeTraitExpression();
1077   case tok::ampamp: {      // unary-expression: '&&' identifier
1078     SourceLocation AmpAmpLoc = ConsumeToken();
1079     if (Tok.isNot(tok::identifier))
1080       return ExprError(Diag(Tok, diag::err_expected) << tok::identifier);
1081 
1082     if (getCurScope()->getFnParent() == nullptr)
1083       return ExprError(Diag(Tok, diag::err_address_of_label_outside_fn));
1084 
1085     Diag(AmpAmpLoc, diag::ext_gnu_address_of_label);
1086     LabelDecl *LD = Actions.LookupOrCreateLabel(Tok.getIdentifierInfo(),
1087                                                 Tok.getLocation());
1088     Res = Actions.ActOnAddrLabel(AmpAmpLoc, Tok.getLocation(), LD);
1089     ConsumeToken();
1090     return Res;
1091   }
1092   case tok::kw_const_cast:
1093   case tok::kw_dynamic_cast:
1094   case tok::kw_reinterpret_cast:
1095   case tok::kw_static_cast:
1096     Res = ParseCXXCasts();
1097     break;
1098   case tok::kw_typeid:
1099     Res = ParseCXXTypeid();
1100     break;
1101   case tok::kw___uuidof:
1102     Res = ParseCXXUuidof();
1103     break;
1104   case tok::kw_this:
1105     Res = ParseCXXThis();
1106     break;
1107 
1108   case tok::annot_typename:
1109     if (isStartOfObjCClassMessageMissingOpenBracket()) {
1110       ParsedType Type = getTypeAnnotation(Tok);
1111 
1112       // Fake up a Declarator to use with ActOnTypeName.
1113       DeclSpec DS(AttrFactory);
1114       DS.SetRangeStart(Tok.getLocation());
1115       DS.SetRangeEnd(Tok.getLastLoc());
1116 
1117       const char *PrevSpec = nullptr;
1118       unsigned DiagID;
1119       DS.SetTypeSpecType(TST_typename, Tok.getAnnotationEndLoc(),
1120                          PrevSpec, DiagID, Type,
1121                          Actions.getASTContext().getPrintingPolicy());
1122 
1123       Declarator DeclaratorInfo(DS, Declarator::TypeNameContext);
1124       TypeResult Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
1125       if (Ty.isInvalid())
1126         break;
1127 
1128       ConsumeToken();
1129       Res = ParseObjCMessageExpressionBody(SourceLocation(), SourceLocation(),
1130                                            Ty.get(), nullptr);
1131       break;
1132     }
1133     // Fall through
1134 
1135   case tok::annot_decltype:
1136   case tok::kw_char:
1137   case tok::kw_wchar_t:
1138   case tok::kw_char16_t:
1139   case tok::kw_char32_t:
1140   case tok::kw_bool:
1141   case tok::kw_short:
1142   case tok::kw_int:
1143   case tok::kw_long:
1144   case tok::kw___int64:
1145   case tok::kw___int128:
1146   case tok::kw_signed:
1147   case tok::kw_unsigned:
1148   case tok::kw_half:
1149   case tok::kw_float:
1150   case tok::kw_double:
1151   case tok::kw_void:
1152   case tok::kw_typename:
1153   case tok::kw_typeof:
1154   case tok::kw___vector: {
1155     if (!getLangOpts().CPlusPlus) {
1156       Diag(Tok, diag::err_expected_expression);
1157       return ExprError();
1158     }
1159 
1160     if (SavedKind == tok::kw_typename) {
1161       // postfix-expression: typename-specifier '(' expression-list[opt] ')'
1162       //                     typename-specifier braced-init-list
1163       if (TryAnnotateTypeOrScopeToken())
1164         return ExprError();
1165 
1166       if (!Actions.isSimpleTypeSpecifier(Tok.getKind()))
1167         // We are trying to parse a simple-type-specifier but might not get such
1168         // a token after error recovery.
1169         return ExprError();
1170     }
1171 
1172     // postfix-expression: simple-type-specifier '(' expression-list[opt] ')'
1173     //                     simple-type-specifier braced-init-list
1174     //
1175     DeclSpec DS(AttrFactory);
1176 
1177     ParseCXXSimpleTypeSpecifier(DS);
1178     if (Tok.isNot(tok::l_paren) &&
1179         (!getLangOpts().CPlusPlus11 || Tok.isNot(tok::l_brace)))
1180       return ExprError(Diag(Tok, diag::err_expected_lparen_after_type)
1181                          << DS.getSourceRange());
1182 
1183     if (Tok.is(tok::l_brace))
1184       Diag(Tok, diag::warn_cxx98_compat_generalized_initializer_lists);
1185 
1186     Res = ParseCXXTypeConstructExpression(DS);
1187     break;
1188   }
1189 
1190   case tok::annot_cxxscope: { // [C++] id-expression: qualified-id
1191     // If TryAnnotateTypeOrScopeToken annotates the token, tail recurse.
1192     // (We can end up in this situation after tentative parsing.)
1193     if (TryAnnotateTypeOrScopeToken())
1194       return ExprError();
1195     if (!Tok.is(tok::annot_cxxscope))
1196       return ParseCastExpression(isUnaryExpression, isAddressOfOperand,
1197                                  NotCastExpr, isTypeCast);
1198 
1199     Token Next = NextToken();
1200     if (Next.is(tok::annot_template_id)) {
1201       TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Next);
1202       if (TemplateId->Kind == TNK_Type_template) {
1203         // We have a qualified template-id that we know refers to a
1204         // type, translate it into a type and continue parsing as a
1205         // cast expression.
1206         CXXScopeSpec SS;
1207         ParseOptionalCXXScopeSpecifier(SS, ParsedType(),
1208                                        /*EnteringContext=*/false);
1209         AnnotateTemplateIdTokenAsType();
1210         return ParseCastExpression(isUnaryExpression, isAddressOfOperand,
1211                                    NotCastExpr, isTypeCast);
1212       }
1213     }
1214 
1215     // Parse as an id-expression.
1216     Res = ParseCXXIdExpression(isAddressOfOperand);
1217     break;
1218   }
1219 
1220   case tok::annot_template_id: { // [C++]          template-id
1221     TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
1222     if (TemplateId->Kind == TNK_Type_template) {
1223       // We have a template-id that we know refers to a type,
1224       // translate it into a type and continue parsing as a cast
1225       // expression.
1226       AnnotateTemplateIdTokenAsType();
1227       return ParseCastExpression(isUnaryExpression, isAddressOfOperand,
1228                                  NotCastExpr, isTypeCast);
1229     }
1230 
1231     // Fall through to treat the template-id as an id-expression.
1232   }
1233 
1234   case tok::kw_operator: // [C++] id-expression: operator/conversion-function-id
1235     Res = ParseCXXIdExpression(isAddressOfOperand);
1236     break;
1237 
1238   case tok::coloncolon: {
1239     // ::foo::bar -> global qualified name etc.   If TryAnnotateTypeOrScopeToken
1240     // annotates the token, tail recurse.
1241     if (TryAnnotateTypeOrScopeToken())
1242       return ExprError();
1243     if (!Tok.is(tok::coloncolon))
1244       return ParseCastExpression(isUnaryExpression, isAddressOfOperand);
1245 
1246     // ::new -> [C++] new-expression
1247     // ::delete -> [C++] delete-expression
1248     SourceLocation CCLoc = ConsumeToken();
1249     if (Tok.is(tok::kw_new))
1250       return ParseCXXNewExpression(true, CCLoc);
1251     if (Tok.is(tok::kw_delete))
1252       return ParseCXXDeleteExpression(true, CCLoc);
1253 
1254     // This is not a type name or scope specifier, it is an invalid expression.
1255     Diag(CCLoc, diag::err_expected_expression);
1256     return ExprError();
1257   }
1258 
1259   case tok::kw_new: // [C++] new-expression
1260     return ParseCXXNewExpression(false, Tok.getLocation());
1261 
1262   case tok::kw_delete: // [C++] delete-expression
1263     return ParseCXXDeleteExpression(false, Tok.getLocation());
1264 
1265   case tok::kw_noexcept: { // [C++0x] 'noexcept' '(' expression ')'
1266     Diag(Tok, diag::warn_cxx98_compat_noexcept_expr);
1267     SourceLocation KeyLoc = ConsumeToken();
1268     BalancedDelimiterTracker T(*this, tok::l_paren);
1269 
1270     if (T.expectAndConsume(diag::err_expected_lparen_after, "noexcept"))
1271       return ExprError();
1272     // C++11 [expr.unary.noexcept]p1:
1273     //   The noexcept operator determines whether the evaluation of its operand,
1274     //   which is an unevaluated operand, can throw an exception.
1275     EnterExpressionEvaluationContext Unevaluated(Actions, Sema::Unevaluated);
1276     ExprResult Result = ParseExpression();
1277 
1278     T.consumeClose();
1279 
1280     if (!Result.isInvalid())
1281       Result = Actions.ActOnNoexceptExpr(KeyLoc, T.getOpenLocation(),
1282                                          Result.get(), T.getCloseLocation());
1283     return Result;
1284   }
1285 
1286 #define TYPE_TRAIT(N,Spelling,K) \
1287   case tok::kw_##Spelling:
1288 #include "clang/Basic/TokenKinds.def"
1289     return ParseTypeTrait();
1290 
1291   case tok::kw___array_rank:
1292   case tok::kw___array_extent:
1293     return ParseArrayTypeTrait();
1294 
1295   case tok::kw___is_lvalue_expr:
1296   case tok::kw___is_rvalue_expr:
1297     return ParseExpressionTrait();
1298 
1299   case tok::at: {
1300     SourceLocation AtLoc = ConsumeToken();
1301     return ParseObjCAtExpression(AtLoc);
1302   }
1303   case tok::caret:
1304     Res = ParseBlockLiteralExpression();
1305     break;
1306   case tok::code_completion: {
1307     Actions.CodeCompleteOrdinaryName(getCurScope(), Sema::PCC_Expression);
1308     cutOffParsing();
1309     return ExprError();
1310   }
1311   case tok::l_square:
1312     if (getLangOpts().CPlusPlus11) {
1313       if (getLangOpts().ObjC1) {
1314         // C++11 lambda expressions and Objective-C message sends both start with a
1315         // square bracket.  There are three possibilities here:
1316         // we have a valid lambda expression, we have an invalid lambda
1317         // expression, or we have something that doesn't appear to be a lambda.
1318         // If we're in the last case, we fall back to ParseObjCMessageExpression.
1319         Res = TryParseLambdaExpression();
1320         if (!Res.isInvalid() && !Res.get())
1321           Res = ParseObjCMessageExpression();
1322         break;
1323       }
1324       Res = ParseLambdaExpression();
1325       break;
1326     }
1327     if (getLangOpts().ObjC1) {
1328       Res = ParseObjCMessageExpression();
1329       break;
1330     }
1331     // FALL THROUGH.
1332   default:
1333     NotCastExpr = true;
1334     return ExprError();
1335   }
1336 
1337   // These can be followed by postfix-expr pieces.
1338   return ParsePostfixExpressionSuffix(Res);
1339 }
1340 
1341 /// \brief Once the leading part of a postfix-expression is parsed, this
1342 /// method parses any suffixes that apply.
1343 ///
1344 /// \verbatim
1345 ///       postfix-expression: [C99 6.5.2]
1346 ///         primary-expression
1347 ///         postfix-expression '[' expression ']'
1348 ///         postfix-expression '[' braced-init-list ']'
1349 ///         postfix-expression '(' argument-expression-list[opt] ')'
1350 ///         postfix-expression '.' identifier
1351 ///         postfix-expression '->' identifier
1352 ///         postfix-expression '++'
1353 ///         postfix-expression '--'
1354 ///         '(' type-name ')' '{' initializer-list '}'
1355 ///         '(' type-name ')' '{' initializer-list ',' '}'
1356 ///
1357 ///       argument-expression-list: [C99 6.5.2]
1358 ///         argument-expression ...[opt]
1359 ///         argument-expression-list ',' assignment-expression ...[opt]
1360 /// \endverbatim
1361 ExprResult
ParsePostfixExpressionSuffix(ExprResult LHS)1362 Parser::ParsePostfixExpressionSuffix(ExprResult LHS) {
1363   // Now that the primary-expression piece of the postfix-expression has been
1364   // parsed, see if there are any postfix-expression pieces here.
1365   SourceLocation Loc;
1366   while (1) {
1367     switch (Tok.getKind()) {
1368     case tok::code_completion:
1369       if (InMessageExpression)
1370         return LHS;
1371 
1372       Actions.CodeCompletePostfixExpression(getCurScope(), LHS);
1373       cutOffParsing();
1374       return ExprError();
1375 
1376     case tok::identifier:
1377       // If we see identifier: after an expression, and we're not already in a
1378       // message send, then this is probably a message send with a missing
1379       // opening bracket '['.
1380       if (getLangOpts().ObjC1 && !InMessageExpression &&
1381           (NextToken().is(tok::colon) || NextToken().is(tok::r_square))) {
1382         LHS = ParseObjCMessageExpressionBody(SourceLocation(), SourceLocation(),
1383                                              ParsedType(), LHS.get());
1384         break;
1385       }
1386 
1387       // Fall through; this isn't a message send.
1388 
1389     default:  // Not a postfix-expression suffix.
1390       return LHS;
1391     case tok::l_square: {  // postfix-expression: p-e '[' expression ']'
1392       // If we have a array postfix expression that starts on a new line and
1393       // Objective-C is enabled, it is highly likely that the user forgot a
1394       // semicolon after the base expression and that the array postfix-expr is
1395       // actually another message send.  In this case, do some look-ahead to see
1396       // if the contents of the square brackets are obviously not a valid
1397       // expression and recover by pretending there is no suffix.
1398       if (getLangOpts().ObjC1 && Tok.isAtStartOfLine() &&
1399           isSimpleObjCMessageExpression())
1400         return LHS;
1401 
1402       // Reject array indices starting with a lambda-expression. '[[' is
1403       // reserved for attributes.
1404       if (CheckProhibitedCXX11Attribute())
1405         return ExprError();
1406 
1407       BalancedDelimiterTracker T(*this, tok::l_square);
1408       T.consumeOpen();
1409       Loc = T.getOpenLocation();
1410       ExprResult Idx, Length;
1411       SourceLocation ColonLoc;
1412       if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
1413         Diag(Tok, diag::warn_cxx98_compat_generalized_initializer_lists);
1414         Idx = ParseBraceInitializer();
1415       } else if (getLangOpts().OpenMP) {
1416         ColonProtectionRAIIObject RAII(*this);
1417         // Parse [: or [ expr or [ expr :
1418         if (!Tok.is(tok::colon)) {
1419           // [ expr
1420           Idx = ParseExpression();
1421         }
1422         if (Tok.is(tok::colon)) {
1423           // Consume ':'
1424           ColonLoc = ConsumeToken();
1425           if (Tok.isNot(tok::r_square))
1426             Length = ParseExpression();
1427         }
1428       } else
1429         Idx = ParseExpression();
1430 
1431       SourceLocation RLoc = Tok.getLocation();
1432 
1433       if (!LHS.isInvalid() && !Idx.isInvalid() && !Length.isInvalid() &&
1434           Tok.is(tok::r_square)) {
1435         if (ColonLoc.isValid()) {
1436           LHS = Actions.ActOnOMPArraySectionExpr(LHS.get(), Loc, Idx.get(),
1437                                                  ColonLoc, Length.get(), RLoc);
1438         } else {
1439           LHS = Actions.ActOnArraySubscriptExpr(getCurScope(), LHS.get(), Loc,
1440                                                 Idx.get(), RLoc);
1441         }
1442       } else {
1443         (void)Actions.CorrectDelayedTyposInExpr(LHS);
1444         (void)Actions.CorrectDelayedTyposInExpr(Idx);
1445         (void)Actions.CorrectDelayedTyposInExpr(Length);
1446         LHS = ExprError();
1447         Idx = ExprError();
1448       }
1449 
1450       // Match the ']'.
1451       T.consumeClose();
1452       break;
1453     }
1454 
1455     case tok::l_paren:         // p-e: p-e '(' argument-expression-list[opt] ')'
1456     case tok::lesslessless: {  // p-e: p-e '<<<' argument-expression-list '>>>'
1457                                //   '(' argument-expression-list[opt] ')'
1458       tok::TokenKind OpKind = Tok.getKind();
1459       InMessageExpressionRAIIObject InMessage(*this, false);
1460 
1461       Expr *ExecConfig = nullptr;
1462 
1463       BalancedDelimiterTracker PT(*this, tok::l_paren);
1464 
1465       if (OpKind == tok::lesslessless) {
1466         ExprVector ExecConfigExprs;
1467         CommaLocsTy ExecConfigCommaLocs;
1468         SourceLocation OpenLoc = ConsumeToken();
1469 
1470         if (ParseSimpleExpressionList(ExecConfigExprs, ExecConfigCommaLocs)) {
1471           (void)Actions.CorrectDelayedTyposInExpr(LHS);
1472           LHS = ExprError();
1473         }
1474 
1475         SourceLocation CloseLoc;
1476         if (TryConsumeToken(tok::greatergreatergreater, CloseLoc)) {
1477         } else if (LHS.isInvalid()) {
1478           SkipUntil(tok::greatergreatergreater, StopAtSemi);
1479         } else {
1480           // There was an error closing the brackets
1481           Diag(Tok, diag::err_expected) << tok::greatergreatergreater;
1482           Diag(OpenLoc, diag::note_matching) << tok::lesslessless;
1483           SkipUntil(tok::greatergreatergreater, StopAtSemi);
1484           LHS = ExprError();
1485         }
1486 
1487         if (!LHS.isInvalid()) {
1488           if (ExpectAndConsume(tok::l_paren))
1489             LHS = ExprError();
1490           else
1491             Loc = PrevTokLocation;
1492         }
1493 
1494         if (!LHS.isInvalid()) {
1495           ExprResult ECResult = Actions.ActOnCUDAExecConfigExpr(getCurScope(),
1496                                     OpenLoc,
1497                                     ExecConfigExprs,
1498                                     CloseLoc);
1499           if (ECResult.isInvalid())
1500             LHS = ExprError();
1501           else
1502             ExecConfig = ECResult.get();
1503         }
1504       } else {
1505         PT.consumeOpen();
1506         Loc = PT.getOpenLocation();
1507       }
1508 
1509       ExprVector ArgExprs;
1510       CommaLocsTy CommaLocs;
1511 
1512       if (Tok.is(tok::code_completion)) {
1513         Actions.CodeCompleteCall(getCurScope(), LHS.get(), None);
1514         cutOffParsing();
1515         return ExprError();
1516       }
1517 
1518       if (OpKind == tok::l_paren || !LHS.isInvalid()) {
1519         if (Tok.isNot(tok::r_paren)) {
1520           if (ParseExpressionList(ArgExprs, CommaLocs, [&] {
1521                 Actions.CodeCompleteCall(getCurScope(), LHS.get(), ArgExprs);
1522              })) {
1523             (void)Actions.CorrectDelayedTyposInExpr(LHS);
1524             LHS = ExprError();
1525           } else if (LHS.isInvalid()) {
1526             for (auto &E : ArgExprs)
1527               Actions.CorrectDelayedTyposInExpr(E);
1528           }
1529         }
1530       }
1531 
1532       // Match the ')'.
1533       if (LHS.isInvalid()) {
1534         SkipUntil(tok::r_paren, StopAtSemi);
1535       } else if (Tok.isNot(tok::r_paren)) {
1536         bool HadDelayedTypo = false;
1537         if (Actions.CorrectDelayedTyposInExpr(LHS).get() != LHS.get())
1538           HadDelayedTypo = true;
1539         for (auto &E : ArgExprs)
1540           if (Actions.CorrectDelayedTyposInExpr(E).get() != E)
1541             HadDelayedTypo = true;
1542         // If there were delayed typos in the LHS or ArgExprs, call SkipUntil
1543         // instead of PT.consumeClose() to avoid emitting extra diagnostics for
1544         // the unmatched l_paren.
1545         if (HadDelayedTypo)
1546           SkipUntil(tok::r_paren, StopAtSemi);
1547         else
1548           PT.consumeClose();
1549         LHS = ExprError();
1550       } else {
1551         assert((ArgExprs.size() == 0 ||
1552                 ArgExprs.size()-1 == CommaLocs.size())&&
1553                "Unexpected number of commas!");
1554         LHS = Actions.ActOnCallExpr(getCurScope(), LHS.get(), Loc,
1555                                     ArgExprs, Tok.getLocation(),
1556                                     ExecConfig);
1557         PT.consumeClose();
1558       }
1559 
1560       break;
1561     }
1562     case tok::arrow:
1563     case tok::period: {
1564       // postfix-expression: p-e '->' template[opt] id-expression
1565       // postfix-expression: p-e '.' template[opt] id-expression
1566       tok::TokenKind OpKind = Tok.getKind();
1567       SourceLocation OpLoc = ConsumeToken();  // Eat the "." or "->" token.
1568 
1569       CXXScopeSpec SS;
1570       ParsedType ObjectType;
1571       bool MayBePseudoDestructor = false;
1572       if (getLangOpts().CPlusPlus && !LHS.isInvalid()) {
1573         Expr *Base = LHS.get();
1574         const Type* BaseType = Base->getType().getTypePtrOrNull();
1575         if (BaseType && Tok.is(tok::l_paren) &&
1576             (BaseType->isFunctionType() ||
1577              BaseType->isSpecificPlaceholderType(BuiltinType::BoundMember))) {
1578           Diag(OpLoc, diag::err_function_is_not_record)
1579               << OpKind << Base->getSourceRange()
1580               << FixItHint::CreateRemoval(OpLoc);
1581           return ParsePostfixExpressionSuffix(Base);
1582         }
1583 
1584         LHS = Actions.ActOnStartCXXMemberReference(getCurScope(), Base,
1585                                                    OpLoc, OpKind, ObjectType,
1586                                                    MayBePseudoDestructor);
1587         if (LHS.isInvalid())
1588           break;
1589 
1590         ParseOptionalCXXScopeSpecifier(SS, ObjectType,
1591                                        /*EnteringContext=*/false,
1592                                        &MayBePseudoDestructor);
1593         if (SS.isNotEmpty())
1594           ObjectType = ParsedType();
1595       }
1596 
1597       if (Tok.is(tok::code_completion)) {
1598         // Code completion for a member access expression.
1599         Actions.CodeCompleteMemberReferenceExpr(getCurScope(), LHS.get(),
1600                                                 OpLoc, OpKind == tok::arrow);
1601 
1602         cutOffParsing();
1603         return ExprError();
1604       }
1605 
1606       if (MayBePseudoDestructor && !LHS.isInvalid()) {
1607         LHS = ParseCXXPseudoDestructor(LHS.get(), OpLoc, OpKind, SS,
1608                                        ObjectType);
1609         break;
1610       }
1611 
1612       // Either the action has told us that this cannot be a
1613       // pseudo-destructor expression (based on the type of base
1614       // expression), or we didn't see a '~' in the right place. We
1615       // can still parse a destructor name here, but in that case it
1616       // names a real destructor.
1617       // Allow explicit constructor calls in Microsoft mode.
1618       // FIXME: Add support for explicit call of template constructor.
1619       SourceLocation TemplateKWLoc;
1620       UnqualifiedId Name;
1621       if (getLangOpts().ObjC2 && OpKind == tok::period &&
1622           Tok.is(tok::kw_class)) {
1623         // Objective-C++:
1624         //   After a '.' in a member access expression, treat the keyword
1625         //   'class' as if it were an identifier.
1626         //
1627         // This hack allows property access to the 'class' method because it is
1628         // such a common method name. For other C++ keywords that are
1629         // Objective-C method names, one must use the message send syntax.
1630         IdentifierInfo *Id = Tok.getIdentifierInfo();
1631         SourceLocation Loc = ConsumeToken();
1632         Name.setIdentifier(Id, Loc);
1633       } else if (ParseUnqualifiedId(SS,
1634                                     /*EnteringContext=*/false,
1635                                     /*AllowDestructorName=*/true,
1636                                     /*AllowConstructorName=*/
1637                                       getLangOpts().MicrosoftExt,
1638                                     ObjectType, TemplateKWLoc, Name)) {
1639         (void)Actions.CorrectDelayedTyposInExpr(LHS);
1640         LHS = ExprError();
1641       }
1642 
1643       if (!LHS.isInvalid())
1644         LHS = Actions.ActOnMemberAccessExpr(getCurScope(), LHS.get(), OpLoc,
1645                                             OpKind, SS, TemplateKWLoc, Name,
1646                                  CurParsedObjCImpl ? CurParsedObjCImpl->Dcl
1647                                                    : nullptr);
1648       break;
1649     }
1650     case tok::plusplus:    // postfix-expression: postfix-expression '++'
1651     case tok::minusminus:  // postfix-expression: postfix-expression '--'
1652       if (!LHS.isInvalid()) {
1653         LHS = Actions.ActOnPostfixUnaryOp(getCurScope(), Tok.getLocation(),
1654                                           Tok.getKind(), LHS.get());
1655       }
1656       ConsumeToken();
1657       break;
1658     }
1659   }
1660 }
1661 
1662 /// ParseExprAfterUnaryExprOrTypeTrait - We parsed a typeof/sizeof/alignof/
1663 /// vec_step and we are at the start of an expression or a parenthesized
1664 /// type-id. OpTok is the operand token (typeof/sizeof/alignof). Returns the
1665 /// expression (isCastExpr == false) or the type (isCastExpr == true).
1666 ///
1667 /// \verbatim
1668 ///       unary-expression:  [C99 6.5.3]
1669 ///         'sizeof' unary-expression
1670 ///         'sizeof' '(' type-name ')'
1671 /// [GNU]   '__alignof' unary-expression
1672 /// [GNU]   '__alignof' '(' type-name ')'
1673 /// [C11]   '_Alignof' '(' type-name ')'
1674 /// [C++0x] 'alignof' '(' type-id ')'
1675 ///
1676 /// [GNU]   typeof-specifier:
1677 ///           typeof ( expressions )
1678 ///           typeof ( type-name )
1679 /// [GNU/C++] typeof unary-expression
1680 ///
1681 /// [OpenCL 1.1 6.11.12] vec_step built-in function:
1682 ///           vec_step ( expressions )
1683 ///           vec_step ( type-name )
1684 /// \endverbatim
1685 ExprResult
ParseExprAfterUnaryExprOrTypeTrait(const Token & OpTok,bool & isCastExpr,ParsedType & CastTy,SourceRange & CastRange)1686 Parser::ParseExprAfterUnaryExprOrTypeTrait(const Token &OpTok,
1687                                            bool &isCastExpr,
1688                                            ParsedType &CastTy,
1689                                            SourceRange &CastRange) {
1690 
1691   assert(OpTok.isOneOf(tok::kw_typeof, tok::kw_sizeof, tok::kw___alignof,
1692                        tok::kw_alignof, tok::kw__Alignof, tok::kw_vec_step,
1693                        tok::kw___builtin_omp_required_simd_align) &&
1694          "Not a typeof/sizeof/alignof/vec_step expression!");
1695 
1696   ExprResult Operand;
1697 
1698   // If the operand doesn't start with an '(', it must be an expression.
1699   if (Tok.isNot(tok::l_paren)) {
1700     // If construct allows a form without parenthesis, user may forget to put
1701     // pathenthesis around type name.
1702     if (OpTok.isOneOf(tok::kw_sizeof, tok::kw___alignof, tok::kw_alignof,
1703                       tok::kw__Alignof)) {
1704       if (isTypeIdUnambiguously()) {
1705         DeclSpec DS(AttrFactory);
1706         ParseSpecifierQualifierList(DS);
1707         Declarator DeclaratorInfo(DS, Declarator::TypeNameContext);
1708         ParseDeclarator(DeclaratorInfo);
1709 
1710         SourceLocation LParenLoc = PP.getLocForEndOfToken(OpTok.getLocation());
1711         SourceLocation RParenLoc = PP.getLocForEndOfToken(PrevTokLocation);
1712         Diag(LParenLoc, diag::err_expected_parentheses_around_typename)
1713           << OpTok.getName()
1714           << FixItHint::CreateInsertion(LParenLoc, "(")
1715           << FixItHint::CreateInsertion(RParenLoc, ")");
1716         isCastExpr = true;
1717         return ExprEmpty();
1718       }
1719     }
1720 
1721     isCastExpr = false;
1722     if (OpTok.is(tok::kw_typeof) && !getLangOpts().CPlusPlus) {
1723       Diag(Tok, diag::err_expected_after) << OpTok.getIdentifierInfo()
1724                                           << tok::l_paren;
1725       return ExprError();
1726     }
1727 
1728     Operand = ParseCastExpression(true/*isUnaryExpression*/);
1729   } else {
1730     // If it starts with a '(', we know that it is either a parenthesized
1731     // type-name, or it is a unary-expression that starts with a compound
1732     // literal, or starts with a primary-expression that is a parenthesized
1733     // expression.
1734     ParenParseOption ExprType = CastExpr;
1735     SourceLocation LParenLoc = Tok.getLocation(), RParenLoc;
1736 
1737     Operand = ParseParenExpression(ExprType, true/*stopIfCastExpr*/,
1738                                    false, CastTy, RParenLoc);
1739     CastRange = SourceRange(LParenLoc, RParenLoc);
1740 
1741     // If ParseParenExpression parsed a '(typename)' sequence only, then this is
1742     // a type.
1743     if (ExprType == CastExpr) {
1744       isCastExpr = true;
1745       return ExprEmpty();
1746     }
1747 
1748     if (getLangOpts().CPlusPlus || OpTok.isNot(tok::kw_typeof)) {
1749       // GNU typeof in C requires the expression to be parenthesized. Not so for
1750       // sizeof/alignof or in C++. Therefore, the parenthesized expression is
1751       // the start of a unary-expression, but doesn't include any postfix
1752       // pieces. Parse these now if present.
1753       if (!Operand.isInvalid())
1754         Operand = ParsePostfixExpressionSuffix(Operand.get());
1755     }
1756   }
1757 
1758   // If we get here, the operand to the typeof/sizeof/alignof was an expresion.
1759   isCastExpr = false;
1760   return Operand;
1761 }
1762 
1763 
1764 /// \brief Parse a sizeof or alignof expression.
1765 ///
1766 /// \verbatim
1767 ///       unary-expression:  [C99 6.5.3]
1768 ///         'sizeof' unary-expression
1769 ///         'sizeof' '(' type-name ')'
1770 /// [C++11] 'sizeof' '...' '(' identifier ')'
1771 /// [GNU]   '__alignof' unary-expression
1772 /// [GNU]   '__alignof' '(' type-name ')'
1773 /// [C11]   '_Alignof' '(' type-name ')'
1774 /// [C++11] 'alignof' '(' type-id ')'
1775 /// \endverbatim
ParseUnaryExprOrTypeTraitExpression()1776 ExprResult Parser::ParseUnaryExprOrTypeTraitExpression() {
1777   assert(Tok.isOneOf(tok::kw_sizeof, tok::kw___alignof, tok::kw_alignof,
1778                      tok::kw__Alignof, tok::kw_vec_step,
1779                      tok::kw___builtin_omp_required_simd_align) &&
1780          "Not a sizeof/alignof/vec_step expression!");
1781   Token OpTok = Tok;
1782   ConsumeToken();
1783 
1784   // [C++11] 'sizeof' '...' '(' identifier ')'
1785   if (Tok.is(tok::ellipsis) && OpTok.is(tok::kw_sizeof)) {
1786     SourceLocation EllipsisLoc = ConsumeToken();
1787     SourceLocation LParenLoc, RParenLoc;
1788     IdentifierInfo *Name = nullptr;
1789     SourceLocation NameLoc;
1790     if (Tok.is(tok::l_paren)) {
1791       BalancedDelimiterTracker T(*this, tok::l_paren);
1792       T.consumeOpen();
1793       LParenLoc = T.getOpenLocation();
1794       if (Tok.is(tok::identifier)) {
1795         Name = Tok.getIdentifierInfo();
1796         NameLoc = ConsumeToken();
1797         T.consumeClose();
1798         RParenLoc = T.getCloseLocation();
1799         if (RParenLoc.isInvalid())
1800           RParenLoc = PP.getLocForEndOfToken(NameLoc);
1801       } else {
1802         Diag(Tok, diag::err_expected_parameter_pack);
1803         SkipUntil(tok::r_paren, StopAtSemi);
1804       }
1805     } else if (Tok.is(tok::identifier)) {
1806       Name = Tok.getIdentifierInfo();
1807       NameLoc = ConsumeToken();
1808       LParenLoc = PP.getLocForEndOfToken(EllipsisLoc);
1809       RParenLoc = PP.getLocForEndOfToken(NameLoc);
1810       Diag(LParenLoc, diag::err_paren_sizeof_parameter_pack)
1811         << Name
1812         << FixItHint::CreateInsertion(LParenLoc, "(")
1813         << FixItHint::CreateInsertion(RParenLoc, ")");
1814     } else {
1815       Diag(Tok, diag::err_sizeof_parameter_pack);
1816     }
1817 
1818     if (!Name)
1819       return ExprError();
1820 
1821     EnterExpressionEvaluationContext Unevaluated(Actions, Sema::Unevaluated,
1822                                                  Sema::ReuseLambdaContextDecl);
1823 
1824     return Actions.ActOnSizeofParameterPackExpr(getCurScope(),
1825                                                 OpTok.getLocation(),
1826                                                 *Name, NameLoc,
1827                                                 RParenLoc);
1828   }
1829 
1830   if (OpTok.isOneOf(tok::kw_alignof, tok::kw__Alignof))
1831     Diag(OpTok, diag::warn_cxx98_compat_alignof);
1832 
1833   EnterExpressionEvaluationContext Unevaluated(Actions, Sema::Unevaluated,
1834                                                Sema::ReuseLambdaContextDecl);
1835 
1836   bool isCastExpr;
1837   ParsedType CastTy;
1838   SourceRange CastRange;
1839   ExprResult Operand = ParseExprAfterUnaryExprOrTypeTrait(OpTok,
1840                                                           isCastExpr,
1841                                                           CastTy,
1842                                                           CastRange);
1843 
1844   UnaryExprOrTypeTrait ExprKind = UETT_SizeOf;
1845   if (OpTok.isOneOf(tok::kw_alignof, tok::kw___alignof, tok::kw__Alignof))
1846     ExprKind = UETT_AlignOf;
1847   else if (OpTok.is(tok::kw_vec_step))
1848     ExprKind = UETT_VecStep;
1849   else if (OpTok.is(tok::kw___builtin_omp_required_simd_align))
1850     ExprKind = UETT_OpenMPRequiredSimdAlign;
1851 
1852   if (isCastExpr)
1853     return Actions.ActOnUnaryExprOrTypeTraitExpr(OpTok.getLocation(),
1854                                                  ExprKind,
1855                                                  /*isType=*/true,
1856                                                  CastTy.getAsOpaquePtr(),
1857                                                  CastRange);
1858 
1859   if (OpTok.isOneOf(tok::kw_alignof, tok::kw__Alignof))
1860     Diag(OpTok, diag::ext_alignof_expr) << OpTok.getIdentifierInfo();
1861 
1862   // If we get here, the operand to the sizeof/alignof was an expresion.
1863   if (!Operand.isInvalid())
1864     Operand = Actions.ActOnUnaryExprOrTypeTraitExpr(OpTok.getLocation(),
1865                                                     ExprKind,
1866                                                     /*isType=*/false,
1867                                                     Operand.get(),
1868                                                     CastRange);
1869   return Operand;
1870 }
1871 
1872 /// ParseBuiltinPrimaryExpression
1873 ///
1874 /// \verbatim
1875 ///       primary-expression: [C99 6.5.1]
1876 /// [GNU]   '__builtin_va_arg' '(' assignment-expression ',' type-name ')'
1877 /// [GNU]   '__builtin_offsetof' '(' type-name ',' offsetof-member-designator')'
1878 /// [GNU]   '__builtin_choose_expr' '(' assign-expr ',' assign-expr ','
1879 ///                                     assign-expr ')'
1880 /// [GNU]   '__builtin_types_compatible_p' '(' type-name ',' type-name ')'
1881 /// [OCL]   '__builtin_astype' '(' assignment-expression ',' type-name ')'
1882 ///
1883 /// [GNU] offsetof-member-designator:
1884 /// [GNU]   identifier
1885 /// [GNU]   offsetof-member-designator '.' identifier
1886 /// [GNU]   offsetof-member-designator '[' expression ']'
1887 /// \endverbatim
ParseBuiltinPrimaryExpression()1888 ExprResult Parser::ParseBuiltinPrimaryExpression() {
1889   ExprResult Res;
1890   const IdentifierInfo *BuiltinII = Tok.getIdentifierInfo();
1891 
1892   tok::TokenKind T = Tok.getKind();
1893   SourceLocation StartLoc = ConsumeToken();   // Eat the builtin identifier.
1894 
1895   // All of these start with an open paren.
1896   if (Tok.isNot(tok::l_paren))
1897     return ExprError(Diag(Tok, diag::err_expected_after) << BuiltinII
1898                                                          << tok::l_paren);
1899 
1900   BalancedDelimiterTracker PT(*this, tok::l_paren);
1901   PT.consumeOpen();
1902 
1903   // TODO: Build AST.
1904 
1905   switch (T) {
1906   default: llvm_unreachable("Not a builtin primary expression!");
1907   case tok::kw___builtin_va_arg: {
1908     ExprResult Expr(ParseAssignmentExpression());
1909 
1910     if (ExpectAndConsume(tok::comma)) {
1911       SkipUntil(tok::r_paren, StopAtSemi);
1912       Expr = ExprError();
1913     }
1914 
1915     TypeResult Ty = ParseTypeName();
1916 
1917     if (Tok.isNot(tok::r_paren)) {
1918       Diag(Tok, diag::err_expected) << tok::r_paren;
1919       Expr = ExprError();
1920     }
1921 
1922     if (Expr.isInvalid() || Ty.isInvalid())
1923       Res = ExprError();
1924     else
1925       Res = Actions.ActOnVAArg(StartLoc, Expr.get(), Ty.get(), ConsumeParen());
1926     break;
1927   }
1928   case tok::kw___builtin_offsetof: {
1929     SourceLocation TypeLoc = Tok.getLocation();
1930     TypeResult Ty = ParseTypeName();
1931     if (Ty.isInvalid()) {
1932       SkipUntil(tok::r_paren, StopAtSemi);
1933       return ExprError();
1934     }
1935 
1936     if (ExpectAndConsume(tok::comma)) {
1937       SkipUntil(tok::r_paren, StopAtSemi);
1938       return ExprError();
1939     }
1940 
1941     // We must have at least one identifier here.
1942     if (Tok.isNot(tok::identifier)) {
1943       Diag(Tok, diag::err_expected) << tok::identifier;
1944       SkipUntil(tok::r_paren, StopAtSemi);
1945       return ExprError();
1946     }
1947 
1948     // Keep track of the various subcomponents we see.
1949     SmallVector<Sema::OffsetOfComponent, 4> Comps;
1950 
1951     Comps.push_back(Sema::OffsetOfComponent());
1952     Comps.back().isBrackets = false;
1953     Comps.back().U.IdentInfo = Tok.getIdentifierInfo();
1954     Comps.back().LocStart = Comps.back().LocEnd = ConsumeToken();
1955 
1956     // FIXME: This loop leaks the index expressions on error.
1957     while (1) {
1958       if (Tok.is(tok::period)) {
1959         // offsetof-member-designator: offsetof-member-designator '.' identifier
1960         Comps.push_back(Sema::OffsetOfComponent());
1961         Comps.back().isBrackets = false;
1962         Comps.back().LocStart = ConsumeToken();
1963 
1964         if (Tok.isNot(tok::identifier)) {
1965           Diag(Tok, diag::err_expected) << tok::identifier;
1966           SkipUntil(tok::r_paren, StopAtSemi);
1967           return ExprError();
1968         }
1969         Comps.back().U.IdentInfo = Tok.getIdentifierInfo();
1970         Comps.back().LocEnd = ConsumeToken();
1971 
1972       } else if (Tok.is(tok::l_square)) {
1973         if (CheckProhibitedCXX11Attribute())
1974           return ExprError();
1975 
1976         // offsetof-member-designator: offsetof-member-design '[' expression ']'
1977         Comps.push_back(Sema::OffsetOfComponent());
1978         Comps.back().isBrackets = true;
1979         BalancedDelimiterTracker ST(*this, tok::l_square);
1980         ST.consumeOpen();
1981         Comps.back().LocStart = ST.getOpenLocation();
1982         Res = ParseExpression();
1983         if (Res.isInvalid()) {
1984           SkipUntil(tok::r_paren, StopAtSemi);
1985           return Res;
1986         }
1987         Comps.back().U.E = Res.get();
1988 
1989         ST.consumeClose();
1990         Comps.back().LocEnd = ST.getCloseLocation();
1991       } else {
1992         if (Tok.isNot(tok::r_paren)) {
1993           PT.consumeClose();
1994           Res = ExprError();
1995         } else if (Ty.isInvalid()) {
1996           Res = ExprError();
1997         } else {
1998           PT.consumeClose();
1999           Res = Actions.ActOnBuiltinOffsetOf(getCurScope(), StartLoc, TypeLoc,
2000                                              Ty.get(), Comps,
2001                                              PT.getCloseLocation());
2002         }
2003         break;
2004       }
2005     }
2006     break;
2007   }
2008   case tok::kw___builtin_choose_expr: {
2009     ExprResult Cond(ParseAssignmentExpression());
2010     if (Cond.isInvalid()) {
2011       SkipUntil(tok::r_paren, StopAtSemi);
2012       return Cond;
2013     }
2014     if (ExpectAndConsume(tok::comma)) {
2015       SkipUntil(tok::r_paren, StopAtSemi);
2016       return ExprError();
2017     }
2018 
2019     ExprResult Expr1(ParseAssignmentExpression());
2020     if (Expr1.isInvalid()) {
2021       SkipUntil(tok::r_paren, StopAtSemi);
2022       return Expr1;
2023     }
2024     if (ExpectAndConsume(tok::comma)) {
2025       SkipUntil(tok::r_paren, StopAtSemi);
2026       return ExprError();
2027     }
2028 
2029     ExprResult Expr2(ParseAssignmentExpression());
2030     if (Expr2.isInvalid()) {
2031       SkipUntil(tok::r_paren, StopAtSemi);
2032       return Expr2;
2033     }
2034     if (Tok.isNot(tok::r_paren)) {
2035       Diag(Tok, diag::err_expected) << tok::r_paren;
2036       return ExprError();
2037     }
2038     Res = Actions.ActOnChooseExpr(StartLoc, Cond.get(), Expr1.get(),
2039                                   Expr2.get(), ConsumeParen());
2040     break;
2041   }
2042   case tok::kw___builtin_astype: {
2043     // The first argument is an expression to be converted, followed by a comma.
2044     ExprResult Expr(ParseAssignmentExpression());
2045     if (Expr.isInvalid()) {
2046       SkipUntil(tok::r_paren, StopAtSemi);
2047       return ExprError();
2048     }
2049 
2050     if (ExpectAndConsume(tok::comma)) {
2051       SkipUntil(tok::r_paren, StopAtSemi);
2052       return ExprError();
2053     }
2054 
2055     // Second argument is the type to bitcast to.
2056     TypeResult DestTy = ParseTypeName();
2057     if (DestTy.isInvalid())
2058       return ExprError();
2059 
2060     // Attempt to consume the r-paren.
2061     if (Tok.isNot(tok::r_paren)) {
2062       Diag(Tok, diag::err_expected) << tok::r_paren;
2063       SkipUntil(tok::r_paren, StopAtSemi);
2064       return ExprError();
2065     }
2066 
2067     Res = Actions.ActOnAsTypeExpr(Expr.get(), DestTy.get(), StartLoc,
2068                                   ConsumeParen());
2069     break;
2070   }
2071   case tok::kw___builtin_convertvector: {
2072     // The first argument is an expression to be converted, followed by a comma.
2073     ExprResult Expr(ParseAssignmentExpression());
2074     if (Expr.isInvalid()) {
2075       SkipUntil(tok::r_paren, StopAtSemi);
2076       return ExprError();
2077     }
2078 
2079     if (ExpectAndConsume(tok::comma)) {
2080       SkipUntil(tok::r_paren, StopAtSemi);
2081       return ExprError();
2082     }
2083 
2084     // Second argument is the type to bitcast to.
2085     TypeResult DestTy = ParseTypeName();
2086     if (DestTy.isInvalid())
2087       return ExprError();
2088 
2089     // Attempt to consume the r-paren.
2090     if (Tok.isNot(tok::r_paren)) {
2091       Diag(Tok, diag::err_expected) << tok::r_paren;
2092       SkipUntil(tok::r_paren, StopAtSemi);
2093       return ExprError();
2094     }
2095 
2096     Res = Actions.ActOnConvertVectorExpr(Expr.get(), DestTy.get(), StartLoc,
2097                                          ConsumeParen());
2098     break;
2099   }
2100   }
2101 
2102   if (Res.isInvalid())
2103     return ExprError();
2104 
2105   // These can be followed by postfix-expr pieces because they are
2106   // primary-expressions.
2107   return ParsePostfixExpressionSuffix(Res.get());
2108 }
2109 
2110 /// ParseParenExpression - This parses the unit that starts with a '(' token,
2111 /// based on what is allowed by ExprType.  The actual thing parsed is returned
2112 /// in ExprType. If stopIfCastExpr is true, it will only return the parsed type,
2113 /// not the parsed cast-expression.
2114 ///
2115 /// \verbatim
2116 ///       primary-expression: [C99 6.5.1]
2117 ///         '(' expression ')'
2118 /// [GNU]   '(' compound-statement ')'      (if !ParenExprOnly)
2119 ///       postfix-expression: [C99 6.5.2]
2120 ///         '(' type-name ')' '{' initializer-list '}'
2121 ///         '(' type-name ')' '{' initializer-list ',' '}'
2122 ///       cast-expression: [C99 6.5.4]
2123 ///         '(' type-name ')' cast-expression
2124 /// [ARC]   bridged-cast-expression
2125 /// [ARC] bridged-cast-expression:
2126 ///         (__bridge type-name) cast-expression
2127 ///         (__bridge_transfer type-name) cast-expression
2128 ///         (__bridge_retained type-name) cast-expression
2129 ///       fold-expression: [C++1z]
2130 ///         '(' cast-expression fold-operator '...' ')'
2131 ///         '(' '...' fold-operator cast-expression ')'
2132 ///         '(' cast-expression fold-operator '...'
2133 ///                 fold-operator cast-expression ')'
2134 /// \endverbatim
2135 ExprResult
ParseParenExpression(ParenParseOption & ExprType,bool stopIfCastExpr,bool isTypeCast,ParsedType & CastTy,SourceLocation & RParenLoc)2136 Parser::ParseParenExpression(ParenParseOption &ExprType, bool stopIfCastExpr,
2137                              bool isTypeCast, ParsedType &CastTy,
2138                              SourceLocation &RParenLoc) {
2139   assert(Tok.is(tok::l_paren) && "Not a paren expr!");
2140   ColonProtectionRAIIObject ColonProtection(*this, false);
2141   BalancedDelimiterTracker T(*this, tok::l_paren);
2142   if (T.consumeOpen())
2143     return ExprError();
2144   SourceLocation OpenLoc = T.getOpenLocation();
2145 
2146   ExprResult Result(true);
2147   bool isAmbiguousTypeId;
2148   CastTy = ParsedType();
2149 
2150   if (Tok.is(tok::code_completion)) {
2151     Actions.CodeCompleteOrdinaryName(getCurScope(),
2152                  ExprType >= CompoundLiteral? Sema::PCC_ParenthesizedExpression
2153                                             : Sema::PCC_Expression);
2154     cutOffParsing();
2155     return ExprError();
2156   }
2157 
2158   // Diagnose use of bridge casts in non-arc mode.
2159   bool BridgeCast = (getLangOpts().ObjC2 &&
2160                      Tok.isOneOf(tok::kw___bridge,
2161                                  tok::kw___bridge_transfer,
2162                                  tok::kw___bridge_retained,
2163                                  tok::kw___bridge_retain));
2164   if (BridgeCast && !getLangOpts().ObjCAutoRefCount) {
2165     if (!TryConsumeToken(tok::kw___bridge)) {
2166       StringRef BridgeCastName = Tok.getName();
2167       SourceLocation BridgeKeywordLoc = ConsumeToken();
2168       if (!PP.getSourceManager().isInSystemHeader(BridgeKeywordLoc))
2169         Diag(BridgeKeywordLoc, diag::warn_arc_bridge_cast_nonarc)
2170           << BridgeCastName
2171           << FixItHint::CreateReplacement(BridgeKeywordLoc, "");
2172     }
2173     BridgeCast = false;
2174   }
2175 
2176   // None of these cases should fall through with an invalid Result
2177   // unless they've already reported an error.
2178   if (ExprType >= CompoundStmt && Tok.is(tok::l_brace)) {
2179     Diag(Tok, diag::ext_gnu_statement_expr);
2180 
2181     if (!getCurScope()->getFnParent() && !getCurScope()->getBlockParent()) {
2182       Result = ExprError(Diag(OpenLoc, diag::err_stmtexpr_file_scope));
2183     } else {
2184       // Find the nearest non-record decl context. Variables declared in a
2185       // statement expression behave as if they were declared in the enclosing
2186       // function, block, or other code construct.
2187       DeclContext *CodeDC = Actions.CurContext;
2188       while (CodeDC->isRecord() || isa<EnumDecl>(CodeDC)) {
2189         CodeDC = CodeDC->getParent();
2190         assert(CodeDC && !CodeDC->isFileContext() &&
2191                "statement expr not in code context");
2192       }
2193       Sema::ContextRAII SavedContext(Actions, CodeDC, /*NewThisContext=*/false);
2194 
2195       Actions.ActOnStartStmtExpr();
2196 
2197       StmtResult Stmt(ParseCompoundStatement(true));
2198       ExprType = CompoundStmt;
2199 
2200       // If the substmt parsed correctly, build the AST node.
2201       if (!Stmt.isInvalid()) {
2202         Result = Actions.ActOnStmtExpr(OpenLoc, Stmt.get(), Tok.getLocation());
2203       } else {
2204         Actions.ActOnStmtExprError();
2205       }
2206     }
2207   } else if (ExprType >= CompoundLiteral && BridgeCast) {
2208     tok::TokenKind tokenKind = Tok.getKind();
2209     SourceLocation BridgeKeywordLoc = ConsumeToken();
2210 
2211     // Parse an Objective-C ARC ownership cast expression.
2212     ObjCBridgeCastKind Kind;
2213     if (tokenKind == tok::kw___bridge)
2214       Kind = OBC_Bridge;
2215     else if (tokenKind == tok::kw___bridge_transfer)
2216       Kind = OBC_BridgeTransfer;
2217     else if (tokenKind == tok::kw___bridge_retained)
2218       Kind = OBC_BridgeRetained;
2219     else {
2220       // As a hopefully temporary workaround, allow __bridge_retain as
2221       // a synonym for __bridge_retained, but only in system headers.
2222       assert(tokenKind == tok::kw___bridge_retain);
2223       Kind = OBC_BridgeRetained;
2224       if (!PP.getSourceManager().isInSystemHeader(BridgeKeywordLoc))
2225         Diag(BridgeKeywordLoc, diag::err_arc_bridge_retain)
2226           << FixItHint::CreateReplacement(BridgeKeywordLoc,
2227                                           "__bridge_retained");
2228     }
2229 
2230     TypeResult Ty = ParseTypeName();
2231     T.consumeClose();
2232     ColonProtection.restore();
2233     RParenLoc = T.getCloseLocation();
2234     ExprResult SubExpr = ParseCastExpression(/*isUnaryExpression=*/false);
2235 
2236     if (Ty.isInvalid() || SubExpr.isInvalid())
2237       return ExprError();
2238 
2239     return Actions.ActOnObjCBridgedCast(getCurScope(), OpenLoc, Kind,
2240                                         BridgeKeywordLoc, Ty.get(),
2241                                         RParenLoc, SubExpr.get());
2242   } else if (ExprType >= CompoundLiteral &&
2243              isTypeIdInParens(isAmbiguousTypeId)) {
2244 
2245     // Otherwise, this is a compound literal expression or cast expression.
2246 
2247     // In C++, if the type-id is ambiguous we disambiguate based on context.
2248     // If stopIfCastExpr is true the context is a typeof/sizeof/alignof
2249     // in which case we should treat it as type-id.
2250     // if stopIfCastExpr is false, we need to determine the context past the
2251     // parens, so we defer to ParseCXXAmbiguousParenExpression for that.
2252     if (isAmbiguousTypeId && !stopIfCastExpr) {
2253       ExprResult res = ParseCXXAmbiguousParenExpression(ExprType, CastTy, T,
2254                                                         ColonProtection);
2255       RParenLoc = T.getCloseLocation();
2256       return res;
2257     }
2258 
2259     // Parse the type declarator.
2260     DeclSpec DS(AttrFactory);
2261     ParseSpecifierQualifierList(DS);
2262     Declarator DeclaratorInfo(DS, Declarator::TypeNameContext);
2263     ParseDeclarator(DeclaratorInfo);
2264 
2265     // If our type is followed by an identifier and either ':' or ']', then
2266     // this is probably an Objective-C message send where the leading '[' is
2267     // missing. Recover as if that were the case.
2268     if (!DeclaratorInfo.isInvalidType() && Tok.is(tok::identifier) &&
2269         !InMessageExpression && getLangOpts().ObjC1 &&
2270         (NextToken().is(tok::colon) || NextToken().is(tok::r_square))) {
2271       TypeResult Ty;
2272       {
2273         InMessageExpressionRAIIObject InMessage(*this, false);
2274         Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
2275       }
2276       Result = ParseObjCMessageExpressionBody(SourceLocation(),
2277                                               SourceLocation(),
2278                                               Ty.get(), nullptr);
2279     } else {
2280       // Match the ')'.
2281       T.consumeClose();
2282       ColonProtection.restore();
2283       RParenLoc = T.getCloseLocation();
2284       if (Tok.is(tok::l_brace)) {
2285         ExprType = CompoundLiteral;
2286         TypeResult Ty;
2287         {
2288           InMessageExpressionRAIIObject InMessage(*this, false);
2289           Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
2290         }
2291         return ParseCompoundLiteralExpression(Ty.get(), OpenLoc, RParenLoc);
2292       }
2293 
2294       if (ExprType == CastExpr) {
2295         // We parsed '(' type-name ')' and the thing after it wasn't a '{'.
2296 
2297         if (DeclaratorInfo.isInvalidType())
2298           return ExprError();
2299 
2300         // Note that this doesn't parse the subsequent cast-expression, it just
2301         // returns the parsed type to the callee.
2302         if (stopIfCastExpr) {
2303           TypeResult Ty;
2304           {
2305             InMessageExpressionRAIIObject InMessage(*this, false);
2306             Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
2307           }
2308           CastTy = Ty.get();
2309           return ExprResult();
2310         }
2311 
2312         // Reject the cast of super idiom in ObjC.
2313         if (Tok.is(tok::identifier) && getLangOpts().ObjC1 &&
2314             Tok.getIdentifierInfo() == Ident_super &&
2315             getCurScope()->isInObjcMethodScope() &&
2316             GetLookAheadToken(1).isNot(tok::period)) {
2317           Diag(Tok.getLocation(), diag::err_illegal_super_cast)
2318             << SourceRange(OpenLoc, RParenLoc);
2319           return ExprError();
2320         }
2321 
2322         // Parse the cast-expression that follows it next.
2323         // TODO: For cast expression with CastTy.
2324         Result = ParseCastExpression(/*isUnaryExpression=*/false,
2325                                      /*isAddressOfOperand=*/false,
2326                                      /*isTypeCast=*/IsTypeCast);
2327         if (!Result.isInvalid()) {
2328           Result = Actions.ActOnCastExpr(getCurScope(), OpenLoc,
2329                                          DeclaratorInfo, CastTy,
2330                                          RParenLoc, Result.get());
2331         }
2332         return Result;
2333       }
2334 
2335       Diag(Tok, diag::err_expected_lbrace_in_compound_literal);
2336       return ExprError();
2337     }
2338   } else if (Tok.is(tok::ellipsis) &&
2339              isFoldOperator(NextToken().getKind())) {
2340     return ParseFoldExpression(ExprResult(), T);
2341   } else if (isTypeCast) {
2342     // Parse the expression-list.
2343     InMessageExpressionRAIIObject InMessage(*this, false);
2344 
2345     ExprVector ArgExprs;
2346     CommaLocsTy CommaLocs;
2347 
2348     if (!ParseSimpleExpressionList(ArgExprs, CommaLocs)) {
2349       // FIXME: If we ever support comma expressions as operands to
2350       // fold-expressions, we'll need to allow multiple ArgExprs here.
2351       if (ArgExprs.size() == 1 && isFoldOperator(Tok.getKind()) &&
2352           NextToken().is(tok::ellipsis))
2353         return ParseFoldExpression(Result, T);
2354 
2355       ExprType = SimpleExpr;
2356       Result = Actions.ActOnParenListExpr(OpenLoc, Tok.getLocation(),
2357                                           ArgExprs);
2358     }
2359   } else {
2360     InMessageExpressionRAIIObject InMessage(*this, false);
2361 
2362     Result = ParseExpression(MaybeTypeCast);
2363     if (!getLangOpts().CPlusPlus && MaybeTypeCast && Result.isUsable()) {
2364       // Correct typos in non-C++ code earlier so that implicit-cast-like
2365       // expressions are parsed correctly.
2366       Result = Actions.CorrectDelayedTyposInExpr(Result);
2367     }
2368     ExprType = SimpleExpr;
2369 
2370     if (isFoldOperator(Tok.getKind()) && NextToken().is(tok::ellipsis))
2371       return ParseFoldExpression(Result, T);
2372 
2373     // Don't build a paren expression unless we actually match a ')'.
2374     if (!Result.isInvalid() && Tok.is(tok::r_paren))
2375       Result =
2376           Actions.ActOnParenExpr(OpenLoc, Tok.getLocation(), Result.get());
2377   }
2378 
2379   // Match the ')'.
2380   if (Result.isInvalid()) {
2381     SkipUntil(tok::r_paren, StopAtSemi);
2382     return ExprError();
2383   }
2384 
2385   T.consumeClose();
2386   RParenLoc = T.getCloseLocation();
2387   return Result;
2388 }
2389 
2390 /// ParseCompoundLiteralExpression - We have parsed the parenthesized type-name
2391 /// and we are at the left brace.
2392 ///
2393 /// \verbatim
2394 ///       postfix-expression: [C99 6.5.2]
2395 ///         '(' type-name ')' '{' initializer-list '}'
2396 ///         '(' type-name ')' '{' initializer-list ',' '}'
2397 /// \endverbatim
2398 ExprResult
ParseCompoundLiteralExpression(ParsedType Ty,SourceLocation LParenLoc,SourceLocation RParenLoc)2399 Parser::ParseCompoundLiteralExpression(ParsedType Ty,
2400                                        SourceLocation LParenLoc,
2401                                        SourceLocation RParenLoc) {
2402   assert(Tok.is(tok::l_brace) && "Not a compound literal!");
2403   if (!getLangOpts().C99)   // Compound literals don't exist in C90.
2404     Diag(LParenLoc, diag::ext_c99_compound_literal);
2405   ExprResult Result = ParseInitializer();
2406   if (!Result.isInvalid() && Ty)
2407     return Actions.ActOnCompoundLiteral(LParenLoc, Ty, RParenLoc, Result.get());
2408   return Result;
2409 }
2410 
2411 /// ParseStringLiteralExpression - This handles the various token types that
2412 /// form string literals, and also handles string concatenation [C99 5.1.1.2,
2413 /// translation phase #6].
2414 ///
2415 /// \verbatim
2416 ///       primary-expression: [C99 6.5.1]
2417 ///         string-literal
2418 /// \verbatim
ParseStringLiteralExpression(bool AllowUserDefinedLiteral)2419 ExprResult Parser::ParseStringLiteralExpression(bool AllowUserDefinedLiteral) {
2420   assert(isTokenStringLiteral() && "Not a string literal!");
2421 
2422   // String concat.  Note that keywords like __func__ and __FUNCTION__ are not
2423   // considered to be strings for concatenation purposes.
2424   SmallVector<Token, 4> StringToks;
2425 
2426   do {
2427     StringToks.push_back(Tok);
2428     ConsumeStringToken();
2429   } while (isTokenStringLiteral());
2430 
2431   // Pass the set of string tokens, ready for concatenation, to the actions.
2432   return Actions.ActOnStringLiteral(StringToks,
2433                                     AllowUserDefinedLiteral ? getCurScope()
2434                                                             : nullptr);
2435 }
2436 
2437 /// ParseGenericSelectionExpression - Parse a C11 generic-selection
2438 /// [C11 6.5.1.1].
2439 ///
2440 /// \verbatim
2441 ///    generic-selection:
2442 ///           _Generic ( assignment-expression , generic-assoc-list )
2443 ///    generic-assoc-list:
2444 ///           generic-association
2445 ///           generic-assoc-list , generic-association
2446 ///    generic-association:
2447 ///           type-name : assignment-expression
2448 ///           default : assignment-expression
2449 /// \endverbatim
ParseGenericSelectionExpression()2450 ExprResult Parser::ParseGenericSelectionExpression() {
2451   assert(Tok.is(tok::kw__Generic) && "_Generic keyword expected");
2452   SourceLocation KeyLoc = ConsumeToken();
2453 
2454   if (!getLangOpts().C11)
2455     Diag(KeyLoc, diag::ext_c11_generic_selection);
2456 
2457   BalancedDelimiterTracker T(*this, tok::l_paren);
2458   if (T.expectAndConsume())
2459     return ExprError();
2460 
2461   ExprResult ControllingExpr;
2462   {
2463     // C11 6.5.1.1p3 "The controlling expression of a generic selection is
2464     // not evaluated."
2465     EnterExpressionEvaluationContext Unevaluated(Actions, Sema::Unevaluated);
2466     ControllingExpr =
2467         Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression());
2468     if (ControllingExpr.isInvalid()) {
2469       SkipUntil(tok::r_paren, StopAtSemi);
2470       return ExprError();
2471     }
2472   }
2473 
2474   if (ExpectAndConsume(tok::comma)) {
2475     SkipUntil(tok::r_paren, StopAtSemi);
2476     return ExprError();
2477   }
2478 
2479   SourceLocation DefaultLoc;
2480   TypeVector Types;
2481   ExprVector Exprs;
2482   do {
2483     ParsedType Ty;
2484     if (Tok.is(tok::kw_default)) {
2485       // C11 6.5.1.1p2 "A generic selection shall have no more than one default
2486       // generic association."
2487       if (!DefaultLoc.isInvalid()) {
2488         Diag(Tok, diag::err_duplicate_default_assoc);
2489         Diag(DefaultLoc, diag::note_previous_default_assoc);
2490         SkipUntil(tok::r_paren, StopAtSemi);
2491         return ExprError();
2492       }
2493       DefaultLoc = ConsumeToken();
2494       Ty = ParsedType();
2495     } else {
2496       ColonProtectionRAIIObject X(*this);
2497       TypeResult TR = ParseTypeName();
2498       if (TR.isInvalid()) {
2499         SkipUntil(tok::r_paren, StopAtSemi);
2500         return ExprError();
2501       }
2502       Ty = TR.get();
2503     }
2504     Types.push_back(Ty);
2505 
2506     if (ExpectAndConsume(tok::colon)) {
2507       SkipUntil(tok::r_paren, StopAtSemi);
2508       return ExprError();
2509     }
2510 
2511     // FIXME: These expressions should be parsed in a potentially potentially
2512     // evaluated context.
2513     ExprResult ER(
2514         Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression()));
2515     if (ER.isInvalid()) {
2516       SkipUntil(tok::r_paren, StopAtSemi);
2517       return ExprError();
2518     }
2519     Exprs.push_back(ER.get());
2520   } while (TryConsumeToken(tok::comma));
2521 
2522   T.consumeClose();
2523   if (T.getCloseLocation().isInvalid())
2524     return ExprError();
2525 
2526   return Actions.ActOnGenericSelectionExpr(KeyLoc, DefaultLoc,
2527                                            T.getCloseLocation(),
2528                                            ControllingExpr.get(),
2529                                            Types, Exprs);
2530 }
2531 
2532 /// \brief Parse A C++1z fold-expression after the opening paren and optional
2533 /// left-hand-side expression.
2534 ///
2535 /// \verbatim
2536 ///   fold-expression:
2537 ///       ( cast-expression fold-operator ... )
2538 ///       ( ... fold-operator cast-expression )
2539 ///       ( cast-expression fold-operator ... fold-operator cast-expression )
ParseFoldExpression(ExprResult LHS,BalancedDelimiterTracker & T)2540 ExprResult Parser::ParseFoldExpression(ExprResult LHS,
2541                                        BalancedDelimiterTracker &T) {
2542   if (LHS.isInvalid()) {
2543     T.skipToEnd();
2544     return true;
2545   }
2546 
2547   tok::TokenKind Kind = tok::unknown;
2548   SourceLocation FirstOpLoc;
2549   if (LHS.isUsable()) {
2550     Kind = Tok.getKind();
2551     assert(isFoldOperator(Kind) && "missing fold-operator");
2552     FirstOpLoc = ConsumeToken();
2553   }
2554 
2555   assert(Tok.is(tok::ellipsis) && "not a fold-expression");
2556   SourceLocation EllipsisLoc = ConsumeToken();
2557 
2558   ExprResult RHS;
2559   if (Tok.isNot(tok::r_paren)) {
2560     if (!isFoldOperator(Tok.getKind()))
2561       return Diag(Tok.getLocation(), diag::err_expected_fold_operator);
2562 
2563     if (Kind != tok::unknown && Tok.getKind() != Kind)
2564       Diag(Tok.getLocation(), diag::err_fold_operator_mismatch)
2565         << SourceRange(FirstOpLoc);
2566     Kind = Tok.getKind();
2567     ConsumeToken();
2568 
2569     RHS = ParseExpression();
2570     if (RHS.isInvalid()) {
2571       T.skipToEnd();
2572       return true;
2573     }
2574   }
2575 
2576   Diag(EllipsisLoc, getLangOpts().CPlusPlus1z
2577                         ? diag::warn_cxx14_compat_fold_expression
2578                         : diag::ext_fold_expression);
2579 
2580   T.consumeClose();
2581   return Actions.ActOnCXXFoldExpr(T.getOpenLocation(), LHS.get(), Kind,
2582                                   EllipsisLoc, RHS.get(), T.getCloseLocation());
2583 }
2584 
2585 /// ParseExpressionList - Used for C/C++ (argument-)expression-list.
2586 ///
2587 /// \verbatim
2588 ///       argument-expression-list:
2589 ///         assignment-expression
2590 ///         argument-expression-list , assignment-expression
2591 ///
2592 /// [C++] expression-list:
2593 /// [C++]   assignment-expression
2594 /// [C++]   expression-list , assignment-expression
2595 ///
2596 /// [C++0x] expression-list:
2597 /// [C++0x]   initializer-list
2598 ///
2599 /// [C++0x] initializer-list
2600 /// [C++0x]   initializer-clause ...[opt]
2601 /// [C++0x]   initializer-list , initializer-clause ...[opt]
2602 ///
2603 /// [C++0x] initializer-clause:
2604 /// [C++0x]   assignment-expression
2605 /// [C++0x]   braced-init-list
2606 /// \endverbatim
ParseExpressionList(SmallVectorImpl<Expr * > & Exprs,SmallVectorImpl<SourceLocation> & CommaLocs,std::function<void ()> Completer)2607 bool Parser::ParseExpressionList(SmallVectorImpl<Expr *> &Exprs,
2608                                  SmallVectorImpl<SourceLocation> &CommaLocs,
2609                                  std::function<void()> Completer) {
2610   bool SawError = false;
2611   while (1) {
2612     if (Tok.is(tok::code_completion)) {
2613       if (Completer)
2614         Completer();
2615       else
2616         Actions.CodeCompleteOrdinaryName(getCurScope(), Sema::PCC_Expression);
2617       cutOffParsing();
2618       return true;
2619     }
2620 
2621     ExprResult Expr;
2622     if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
2623       Diag(Tok, diag::warn_cxx98_compat_generalized_initializer_lists);
2624       Expr = ParseBraceInitializer();
2625     } else
2626       Expr = ParseAssignmentExpression();
2627 
2628     if (Tok.is(tok::ellipsis))
2629       Expr = Actions.ActOnPackExpansion(Expr.get(), ConsumeToken());
2630     if (Expr.isInvalid()) {
2631       SkipUntil(tok::comma, tok::r_paren, StopBeforeMatch);
2632       SawError = true;
2633     } else {
2634       Exprs.push_back(Expr.get());
2635     }
2636 
2637     if (Tok.isNot(tok::comma))
2638       break;
2639     // Move to the next argument, remember where the comma was.
2640     CommaLocs.push_back(ConsumeToken());
2641   }
2642   if (SawError) {
2643     // Ensure typos get diagnosed when errors were encountered while parsing the
2644     // expression list.
2645     for (auto &E : Exprs) {
2646       ExprResult Expr = Actions.CorrectDelayedTyposInExpr(E);
2647       if (Expr.isUsable()) E = Expr.get();
2648     }
2649   }
2650   return SawError;
2651 }
2652 
2653 /// ParseSimpleExpressionList - A simple comma-separated list of expressions,
2654 /// used for misc language extensions.
2655 ///
2656 /// \verbatim
2657 ///       simple-expression-list:
2658 ///         assignment-expression
2659 ///         simple-expression-list , assignment-expression
2660 /// \endverbatim
2661 bool
ParseSimpleExpressionList(SmallVectorImpl<Expr * > & Exprs,SmallVectorImpl<SourceLocation> & CommaLocs)2662 Parser::ParseSimpleExpressionList(SmallVectorImpl<Expr*> &Exprs,
2663                                   SmallVectorImpl<SourceLocation> &CommaLocs) {
2664   while (1) {
2665     ExprResult Expr = ParseAssignmentExpression();
2666     if (Expr.isInvalid())
2667       return true;
2668 
2669     Exprs.push_back(Expr.get());
2670 
2671     if (Tok.isNot(tok::comma))
2672       return false;
2673 
2674     // Move to the next argument, remember where the comma was.
2675     CommaLocs.push_back(ConsumeToken());
2676   }
2677 }
2678 
2679 /// ParseBlockId - Parse a block-id, which roughly looks like int (int x).
2680 ///
2681 /// \verbatim
2682 /// [clang] block-id:
2683 /// [clang]   specifier-qualifier-list block-declarator
2684 /// \endverbatim
ParseBlockId(SourceLocation CaretLoc)2685 void Parser::ParseBlockId(SourceLocation CaretLoc) {
2686   if (Tok.is(tok::code_completion)) {
2687     Actions.CodeCompleteOrdinaryName(getCurScope(), Sema::PCC_Type);
2688     return cutOffParsing();
2689   }
2690 
2691   // Parse the specifier-qualifier-list piece.
2692   DeclSpec DS(AttrFactory);
2693   ParseSpecifierQualifierList(DS);
2694 
2695   // Parse the block-declarator.
2696   Declarator DeclaratorInfo(DS, Declarator::BlockLiteralContext);
2697   ParseDeclarator(DeclaratorInfo);
2698 
2699   MaybeParseGNUAttributes(DeclaratorInfo);
2700 
2701   // Inform sema that we are starting a block.
2702   Actions.ActOnBlockArguments(CaretLoc, DeclaratorInfo, getCurScope());
2703 }
2704 
2705 /// ParseBlockLiteralExpression - Parse a block literal, which roughly looks
2706 /// like ^(int x){ return x+1; }
2707 ///
2708 /// \verbatim
2709 ///         block-literal:
2710 /// [clang]   '^' block-args[opt] compound-statement
2711 /// [clang]   '^' block-id compound-statement
2712 /// [clang] block-args:
2713 /// [clang]   '(' parameter-list ')'
2714 /// \endverbatim
ParseBlockLiteralExpression()2715 ExprResult Parser::ParseBlockLiteralExpression() {
2716   assert(Tok.is(tok::caret) && "block literal starts with ^");
2717   SourceLocation CaretLoc = ConsumeToken();
2718 
2719   PrettyStackTraceLoc CrashInfo(PP.getSourceManager(), CaretLoc,
2720                                 "block literal parsing");
2721 
2722   // Enter a scope to hold everything within the block.  This includes the
2723   // argument decls, decls within the compound expression, etc.  This also
2724   // allows determining whether a variable reference inside the block is
2725   // within or outside of the block.
2726   ParseScope BlockScope(this, Scope::BlockScope | Scope::FnScope |
2727                               Scope::DeclScope);
2728 
2729   // Inform sema that we are starting a block.
2730   Actions.ActOnBlockStart(CaretLoc, getCurScope());
2731 
2732   // Parse the return type if present.
2733   DeclSpec DS(AttrFactory);
2734   Declarator ParamInfo(DS, Declarator::BlockLiteralContext);
2735   // FIXME: Since the return type isn't actually parsed, it can't be used to
2736   // fill ParamInfo with an initial valid range, so do it manually.
2737   ParamInfo.SetSourceRange(SourceRange(Tok.getLocation(), Tok.getLocation()));
2738 
2739   // If this block has arguments, parse them.  There is no ambiguity here with
2740   // the expression case, because the expression case requires a parameter list.
2741   if (Tok.is(tok::l_paren)) {
2742     ParseParenDeclarator(ParamInfo);
2743     // Parse the pieces after the identifier as if we had "int(...)".
2744     // SetIdentifier sets the source range end, but in this case we're past
2745     // that location.
2746     SourceLocation Tmp = ParamInfo.getSourceRange().getEnd();
2747     ParamInfo.SetIdentifier(nullptr, CaretLoc);
2748     ParamInfo.SetRangeEnd(Tmp);
2749     if (ParamInfo.isInvalidType()) {
2750       // If there was an error parsing the arguments, they may have
2751       // tried to use ^(x+y) which requires an argument list.  Just
2752       // skip the whole block literal.
2753       Actions.ActOnBlockError(CaretLoc, getCurScope());
2754       return ExprError();
2755     }
2756 
2757     MaybeParseGNUAttributes(ParamInfo);
2758 
2759     // Inform sema that we are starting a block.
2760     Actions.ActOnBlockArguments(CaretLoc, ParamInfo, getCurScope());
2761   } else if (!Tok.is(tok::l_brace)) {
2762     ParseBlockId(CaretLoc);
2763   } else {
2764     // Otherwise, pretend we saw (void).
2765     ParsedAttributes attrs(AttrFactory);
2766     SourceLocation NoLoc;
2767     ParamInfo.AddTypeInfo(DeclaratorChunk::getFunction(/*HasProto=*/true,
2768                                              /*IsAmbiguous=*/false,
2769                                              /*RParenLoc=*/NoLoc,
2770                                              /*ArgInfo=*/nullptr,
2771                                              /*NumArgs=*/0,
2772                                              /*EllipsisLoc=*/NoLoc,
2773                                              /*RParenLoc=*/NoLoc,
2774                                              /*TypeQuals=*/0,
2775                                              /*RefQualifierIsLvalueRef=*/true,
2776                                              /*RefQualifierLoc=*/NoLoc,
2777                                              /*ConstQualifierLoc=*/NoLoc,
2778                                              /*VolatileQualifierLoc=*/NoLoc,
2779                                              /*RestrictQualifierLoc=*/NoLoc,
2780                                              /*MutableLoc=*/NoLoc,
2781                                              EST_None,
2782                                              /*ESpecRange=*/SourceRange(),
2783                                              /*Exceptions=*/nullptr,
2784                                              /*ExceptionRanges=*/nullptr,
2785                                              /*NumExceptions=*/0,
2786                                              /*NoexceptExpr=*/nullptr,
2787                                              /*ExceptionSpecTokens=*/nullptr,
2788                                              CaretLoc, CaretLoc,
2789                                              ParamInfo),
2790                           attrs, CaretLoc);
2791 
2792     MaybeParseGNUAttributes(ParamInfo);
2793 
2794     // Inform sema that we are starting a block.
2795     Actions.ActOnBlockArguments(CaretLoc, ParamInfo, getCurScope());
2796   }
2797 
2798 
2799   ExprResult Result(true);
2800   if (!Tok.is(tok::l_brace)) {
2801     // Saw something like: ^expr
2802     Diag(Tok, diag::err_expected_expression);
2803     Actions.ActOnBlockError(CaretLoc, getCurScope());
2804     return ExprError();
2805   }
2806 
2807   StmtResult Stmt(ParseCompoundStatementBody());
2808   BlockScope.Exit();
2809   if (!Stmt.isInvalid())
2810     Result = Actions.ActOnBlockStmtExpr(CaretLoc, Stmt.get(), getCurScope());
2811   else
2812     Actions.ActOnBlockError(CaretLoc, getCurScope());
2813   return Result;
2814 }
2815 
2816 /// ParseObjCBoolLiteral - This handles the objective-c Boolean literals.
2817 ///
2818 ///         '__objc_yes'
2819 ///         '__objc_no'
ParseObjCBoolLiteral()2820 ExprResult Parser::ParseObjCBoolLiteral() {
2821   tok::TokenKind Kind = Tok.getKind();
2822   return Actions.ActOnObjCBoolLiteral(ConsumeToken(), Kind);
2823 }
2824