1 //===--- ParseExpr.cpp - Expression Parsing -------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// Provides the Expression parsing implementation.
11 ///
12 /// Expressions in C99 basically consist of a bunch of binary operators with
13 /// unary operators and other random stuff at the leaves.
14 ///
15 /// In the C99 grammar, these unary operators bind tightest and are represented
16 /// as the 'cast-expression' production.  Everything else is either a binary
17 /// operator (e.g. '/') or a ternary operator ("?:").  The unary leaves are
18 /// handled by ParseCastExpression, the higher level pieces are handled by
19 /// ParseBinaryExpression.
20 ///
21 //===----------------------------------------------------------------------===//
22 
23 #include "clang/Parse/Parser.h"
24 #include "clang/AST/ASTContext.h"
25 #include "clang/AST/ExprCXX.h"
26 #include "clang/Basic/PrettyStackTrace.h"
27 #include "clang/Parse/RAIIObjectsForParser.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/SmallVector.h"
33 using namespace clang;
34 
35 /// Simple precedence-based parser for binary/ternary operators.
36 ///
37 /// Note: we diverge from the C99 grammar when parsing the assignment-expression
38 /// production.  C99 specifies that the LHS of an assignment operator should be
39 /// parsed as a unary-expression, but consistency dictates that it be a
40 /// conditional-expession.  In practice, the important thing here is that the
41 /// LHS of an assignment has to be an l-value, which productions between
42 /// unary-expression and conditional-expression don't produce.  Because we want
43 /// consistency, we parse the LHS as a conditional-expression, then check for
44 /// l-value-ness in semantic analysis stages.
45 ///
46 /// \verbatim
47 ///       pm-expression: [C++ 5.5]
48 ///         cast-expression
49 ///         pm-expression '.*' cast-expression
50 ///         pm-expression '->*' cast-expression
51 ///
52 ///       multiplicative-expression: [C99 6.5.5]
53 ///     Note: in C++, apply pm-expression instead of cast-expression
54 ///         cast-expression
55 ///         multiplicative-expression '*' cast-expression
56 ///         multiplicative-expression '/' cast-expression
57 ///         multiplicative-expression '%' cast-expression
58 ///
59 ///       additive-expression: [C99 6.5.6]
60 ///         multiplicative-expression
61 ///         additive-expression '+' multiplicative-expression
62 ///         additive-expression '-' multiplicative-expression
63 ///
64 ///       shift-expression: [C99 6.5.7]
65 ///         additive-expression
66 ///         shift-expression '<<' additive-expression
67 ///         shift-expression '>>' additive-expression
68 ///
69 ///       compare-expression: [C++20 expr.spaceship]
70 ///         shift-expression
71 ///         compare-expression '<=>' shift-expression
72 ///
73 ///       relational-expression: [C99 6.5.8]
74 ///         compare-expression
75 ///         relational-expression '<' compare-expression
76 ///         relational-expression '>' compare-expression
77 ///         relational-expression '<=' compare-expression
78 ///         relational-expression '>=' compare-expression
79 ///
80 ///       equality-expression: [C99 6.5.9]
81 ///         relational-expression
82 ///         equality-expression '==' relational-expression
83 ///         equality-expression '!=' relational-expression
84 ///
85 ///       AND-expression: [C99 6.5.10]
86 ///         equality-expression
87 ///         AND-expression '&' equality-expression
88 ///
89 ///       exclusive-OR-expression: [C99 6.5.11]
90 ///         AND-expression
91 ///         exclusive-OR-expression '^' AND-expression
92 ///
93 ///       inclusive-OR-expression: [C99 6.5.12]
94 ///         exclusive-OR-expression
95 ///         inclusive-OR-expression '|' exclusive-OR-expression
96 ///
97 ///       logical-AND-expression: [C99 6.5.13]
98 ///         inclusive-OR-expression
99 ///         logical-AND-expression '&&' inclusive-OR-expression
100 ///
101 ///       logical-OR-expression: [C99 6.5.14]
102 ///         logical-AND-expression
103 ///         logical-OR-expression '||' logical-AND-expression
104 ///
105 ///       conditional-expression: [C99 6.5.15]
106 ///         logical-OR-expression
107 ///         logical-OR-expression '?' expression ':' conditional-expression
108 /// [GNU]   logical-OR-expression '?' ':' conditional-expression
109 /// [C++] the third operand is an assignment-expression
110 ///
111 ///       assignment-expression: [C99 6.5.16]
112 ///         conditional-expression
113 ///         unary-expression assignment-operator assignment-expression
114 /// [C++]   throw-expression [C++ 15]
115 ///
116 ///       assignment-operator: one of
117 ///         = *= /= %= += -= <<= >>= &= ^= |=
118 ///
119 ///       expression: [C99 6.5.17]
120 ///         assignment-expression ...[opt]
121 ///         expression ',' assignment-expression ...[opt]
122 /// \endverbatim
ParseExpression(TypeCastState isTypeCast)123 ExprResult Parser::ParseExpression(TypeCastState isTypeCast) {
124   ExprResult LHS(ParseAssignmentExpression(isTypeCast));
125   return ParseRHSOfBinaryExpression(LHS, prec::Comma);
126 }
127 
128 /// This routine is called when the '@' is seen and consumed.
129 /// Current token is an Identifier and is not a 'try'. This
130 /// routine is necessary to disambiguate \@try-statement from,
131 /// for example, \@encode-expression.
132 ///
133 ExprResult
ParseExpressionWithLeadingAt(SourceLocation AtLoc)134 Parser::ParseExpressionWithLeadingAt(SourceLocation AtLoc) {
135   ExprResult LHS(ParseObjCAtExpression(AtLoc));
136   return ParseRHSOfBinaryExpression(LHS, prec::Comma);
137 }
138 
139 /// This routine is called when a leading '__extension__' is seen and
140 /// consumed.  This is necessary because the token gets consumed in the
141 /// process of disambiguating between an expression and a declaration.
142 ExprResult
ParseExpressionWithLeadingExtension(SourceLocation ExtLoc)143 Parser::ParseExpressionWithLeadingExtension(SourceLocation ExtLoc) {
144   ExprResult LHS(true);
145   {
146     // Silence extension warnings in the sub-expression
147     ExtensionRAIIObject O(Diags);
148 
149     LHS = ParseCastExpression(AnyCastExpr);
150   }
151 
152   if (!LHS.isInvalid())
153     LHS = Actions.ActOnUnaryOp(getCurScope(), ExtLoc, tok::kw___extension__,
154                                LHS.get());
155 
156   return ParseRHSOfBinaryExpression(LHS, prec::Comma);
157 }
158 
159 /// Parse an expr that doesn't include (top-level) commas.
ParseAssignmentExpression(TypeCastState isTypeCast)160 ExprResult Parser::ParseAssignmentExpression(TypeCastState isTypeCast) {
161   if (Tok.is(tok::code_completion)) {
162     cutOffParsing();
163     Actions.CodeCompleteExpression(getCurScope(),
164                                    PreferredType.get(Tok.getLocation()));
165     return ExprError();
166   }
167 
168   if (Tok.is(tok::kw_throw))
169     return ParseThrowExpression();
170   if (Tok.is(tok::kw_co_yield))
171     return ParseCoyieldExpression();
172 
173   ExprResult LHS = ParseCastExpression(AnyCastExpr,
174                                        /*isAddressOfOperand=*/false,
175                                        isTypeCast);
176   return ParseRHSOfBinaryExpression(LHS, prec::Assignment);
177 }
178 
179 /// Parse an assignment expression where part of an Objective-C message
180 /// send has already been parsed.
181 ///
182 /// In this case \p LBracLoc indicates the location of the '[' of the message
183 /// send, and either \p ReceiverName or \p ReceiverExpr is non-null indicating
184 /// the receiver of the message.
185 ///
186 /// Since this handles full assignment-expression's, it handles postfix
187 /// expressions and other binary operators for these expressions as well.
188 ExprResult
ParseAssignmentExprWithObjCMessageExprStart(SourceLocation LBracLoc,SourceLocation SuperLoc,ParsedType ReceiverType,Expr * ReceiverExpr)189 Parser::ParseAssignmentExprWithObjCMessageExprStart(SourceLocation LBracLoc,
190                                                     SourceLocation SuperLoc,
191                                                     ParsedType ReceiverType,
192                                                     Expr *ReceiverExpr) {
193   ExprResult R
194     = ParseObjCMessageExpressionBody(LBracLoc, SuperLoc,
195                                      ReceiverType, ReceiverExpr);
196   R = ParsePostfixExpressionSuffix(R);
197   return ParseRHSOfBinaryExpression(R, prec::Assignment);
198 }
199 
200 ExprResult
ParseConstantExpressionInExprEvalContext(TypeCastState isTypeCast)201 Parser::ParseConstantExpressionInExprEvalContext(TypeCastState isTypeCast) {
202   assert(Actions.ExprEvalContexts.back().Context ==
203              Sema::ExpressionEvaluationContext::ConstantEvaluated &&
204          "Call this function only if your ExpressionEvaluationContext is "
205          "already ConstantEvaluated");
206   ExprResult LHS(ParseCastExpression(AnyCastExpr, false, isTypeCast));
207   ExprResult Res(ParseRHSOfBinaryExpression(LHS, prec::Conditional));
208   return Actions.ActOnConstantExpression(Res);
209 }
210 
ParseConstantExpression(TypeCastState isTypeCast)211 ExprResult Parser::ParseConstantExpression(TypeCastState isTypeCast) {
212   // C++03 [basic.def.odr]p2:
213   //   An expression is potentially evaluated unless it appears where an
214   //   integral constant expression is required (see 5.19) [...].
215   // C++98 and C++11 have no such rule, but this is only a defect in C++98.
216   EnterExpressionEvaluationContext ConstantEvaluated(
217       Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated);
218   return ParseConstantExpressionInExprEvalContext(isTypeCast);
219 }
220 
ParseCaseExpression(SourceLocation CaseLoc)221 ExprResult Parser::ParseCaseExpression(SourceLocation CaseLoc) {
222   EnterExpressionEvaluationContext ConstantEvaluated(
223       Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated);
224   ExprResult LHS(ParseCastExpression(AnyCastExpr, false, NotTypeCast));
225   ExprResult Res(ParseRHSOfBinaryExpression(LHS, prec::Conditional));
226   return Actions.ActOnCaseExpr(CaseLoc, Res);
227 }
228 
229 /// Parse a constraint-expression.
230 ///
231 /// \verbatim
232 ///       constraint-expression: C++2a[temp.constr.decl]p1
233 ///         logical-or-expression
234 /// \endverbatim
ParseConstraintExpression()235 ExprResult Parser::ParseConstraintExpression() {
236   EnterExpressionEvaluationContext ConstantEvaluated(
237       Actions, Sema::ExpressionEvaluationContext::Unevaluated);
238   ExprResult LHS(ParseCastExpression(AnyCastExpr));
239   ExprResult Res(ParseRHSOfBinaryExpression(LHS, prec::LogicalOr));
240   if (Res.isUsable() && !Actions.CheckConstraintExpression(Res.get())) {
241     Actions.CorrectDelayedTyposInExpr(Res);
242     return ExprError();
243   }
244   return Res;
245 }
246 
247 /// \brief Parse a constraint-logical-and-expression.
248 ///
249 /// \verbatim
250 ///       C++2a[temp.constr.decl]p1
251 ///       constraint-logical-and-expression:
252 ///         primary-expression
253 ///         constraint-logical-and-expression '&&' primary-expression
254 ///
255 /// \endverbatim
256 ExprResult
ParseConstraintLogicalAndExpression(bool IsTrailingRequiresClause)257 Parser::ParseConstraintLogicalAndExpression(bool IsTrailingRequiresClause) {
258   EnterExpressionEvaluationContext ConstantEvaluated(
259       Actions, Sema::ExpressionEvaluationContext::Unevaluated);
260   bool NotPrimaryExpression = false;
261   auto ParsePrimary = [&] () {
262     ExprResult E = ParseCastExpression(PrimaryExprOnly,
263                                        /*isAddressOfOperand=*/false,
264                                        /*isTypeCast=*/NotTypeCast,
265                                        /*isVectorLiteral=*/false,
266                                        &NotPrimaryExpression);
267     if (E.isInvalid())
268       return ExprError();
269     auto RecoverFromNonPrimary = [&] (ExprResult E, bool Note) {
270         E = ParsePostfixExpressionSuffix(E);
271         // Use InclusiveOr, the precedence just after '&&' to not parse the
272         // next arguments to the logical and.
273         E = ParseRHSOfBinaryExpression(E, prec::InclusiveOr);
274         if (!E.isInvalid())
275           Diag(E.get()->getExprLoc(),
276                Note
277                ? diag::note_unparenthesized_non_primary_expr_in_requires_clause
278                : diag::err_unparenthesized_non_primary_expr_in_requires_clause)
279                << FixItHint::CreateInsertion(E.get()->getBeginLoc(), "(")
280                << FixItHint::CreateInsertion(
281                    PP.getLocForEndOfToken(E.get()->getEndLoc()), ")")
282                << E.get()->getSourceRange();
283         return E;
284     };
285 
286     if (NotPrimaryExpression ||
287         // Check if the following tokens must be a part of a non-primary
288         // expression
289         getBinOpPrecedence(Tok.getKind(), GreaterThanIsOperator,
290                            /*CPlusPlus11=*/true) > prec::LogicalAnd ||
291         // Postfix operators other than '(' (which will be checked for in
292         // CheckConstraintExpression).
293         Tok.isOneOf(tok::period, tok::plusplus, tok::minusminus) ||
294         (Tok.is(tok::l_square) && !NextToken().is(tok::l_square))) {
295       E = RecoverFromNonPrimary(E, /*Note=*/false);
296       if (E.isInvalid())
297         return ExprError();
298       NotPrimaryExpression = false;
299     }
300     bool PossibleNonPrimary;
301     bool IsConstraintExpr =
302         Actions.CheckConstraintExpression(E.get(), Tok, &PossibleNonPrimary,
303                                           IsTrailingRequiresClause);
304     if (!IsConstraintExpr || PossibleNonPrimary) {
305       // Atomic constraint might be an unparenthesized non-primary expression
306       // (such as a binary operator), in which case we might get here (e.g. in
307       // 'requires 0 + 1 && true' we would now be at '+', and parse and ignore
308       // the rest of the addition expression). Try to parse the rest of it here.
309       if (PossibleNonPrimary)
310         E = RecoverFromNonPrimary(E, /*Note=*/!IsConstraintExpr);
311       Actions.CorrectDelayedTyposInExpr(E);
312       return ExprError();
313     }
314     return E;
315   };
316   ExprResult LHS = ParsePrimary();
317   if (LHS.isInvalid())
318     return ExprError();
319   while (Tok.is(tok::ampamp)) {
320     SourceLocation LogicalAndLoc = ConsumeToken();
321     ExprResult RHS = ParsePrimary();
322     if (RHS.isInvalid()) {
323       Actions.CorrectDelayedTyposInExpr(LHS);
324       return ExprError();
325     }
326     ExprResult Op = Actions.ActOnBinOp(getCurScope(), LogicalAndLoc,
327                                        tok::ampamp, LHS.get(), RHS.get());
328     if (!Op.isUsable()) {
329       Actions.CorrectDelayedTyposInExpr(RHS);
330       Actions.CorrectDelayedTyposInExpr(LHS);
331       return ExprError();
332     }
333     LHS = Op;
334   }
335   return LHS;
336 }
337 
338 /// \brief Parse a constraint-logical-or-expression.
339 ///
340 /// \verbatim
341 ///       C++2a[temp.constr.decl]p1
342 ///       constraint-logical-or-expression:
343 ///         constraint-logical-and-expression
344 ///         constraint-logical-or-expression '||'
345 ///             constraint-logical-and-expression
346 ///
347 /// \endverbatim
348 ExprResult
ParseConstraintLogicalOrExpression(bool IsTrailingRequiresClause)349 Parser::ParseConstraintLogicalOrExpression(bool IsTrailingRequiresClause) {
350   ExprResult LHS(ParseConstraintLogicalAndExpression(IsTrailingRequiresClause));
351   if (!LHS.isUsable())
352     return ExprError();
353   while (Tok.is(tok::pipepipe)) {
354     SourceLocation LogicalOrLoc = ConsumeToken();
355     ExprResult RHS =
356         ParseConstraintLogicalAndExpression(IsTrailingRequiresClause);
357     if (!RHS.isUsable()) {
358       Actions.CorrectDelayedTyposInExpr(LHS);
359       return ExprError();
360     }
361     ExprResult Op = Actions.ActOnBinOp(getCurScope(), LogicalOrLoc,
362                                        tok::pipepipe, LHS.get(), RHS.get());
363     if (!Op.isUsable()) {
364       Actions.CorrectDelayedTyposInExpr(RHS);
365       Actions.CorrectDelayedTyposInExpr(LHS);
366       return ExprError();
367     }
368     LHS = Op;
369   }
370   return LHS;
371 }
372 
isNotExpressionStart()373 bool Parser::isNotExpressionStart() {
374   tok::TokenKind K = Tok.getKind();
375   if (K == tok::l_brace || K == tok::r_brace  ||
376       K == tok::kw_for  || K == tok::kw_while ||
377       K == tok::kw_if   || K == tok::kw_else  ||
378       K == tok::kw_goto || K == tok::kw_try)
379     return true;
380   // If this is a decl-specifier, we can't be at the start of an expression.
381   return isKnownToBeDeclarationSpecifier();
382 }
383 
isFoldOperator(prec::Level Level) const384 bool Parser::isFoldOperator(prec::Level Level) const {
385   return Level > prec::Unknown && Level != prec::Conditional &&
386          Level != prec::Spaceship;
387 }
388 
isFoldOperator(tok::TokenKind Kind) const389 bool Parser::isFoldOperator(tok::TokenKind Kind) const {
390   return isFoldOperator(getBinOpPrecedence(Kind, GreaterThanIsOperator, true));
391 }
392 
393 /// Parse a binary expression that starts with \p LHS and has a
394 /// precedence of at least \p MinPrec.
395 ExprResult
ParseRHSOfBinaryExpression(ExprResult LHS,prec::Level MinPrec)396 Parser::ParseRHSOfBinaryExpression(ExprResult LHS, prec::Level MinPrec) {
397   prec::Level NextTokPrec = getBinOpPrecedence(Tok.getKind(),
398                                                GreaterThanIsOperator,
399                                                getLangOpts().CPlusPlus11);
400   SourceLocation ColonLoc;
401 
402   auto SavedType = PreferredType;
403   while (1) {
404     // Every iteration may rely on a preferred type for the whole expression.
405     PreferredType = SavedType;
406     // If this token has a lower precedence than we are allowed to parse (e.g.
407     // because we are called recursively, or because the token is not a binop),
408     // then we are done!
409     if (NextTokPrec < MinPrec)
410       return LHS;
411 
412     // Consume the operator, saving the operator token for error reporting.
413     Token OpToken = Tok;
414     ConsumeToken();
415 
416     if (OpToken.is(tok::caretcaret)) {
417       return ExprError(Diag(Tok, diag::err_opencl_logical_exclusive_or));
418     }
419 
420     // If we're potentially in a template-id, we may now be able to determine
421     // whether we're actually in one or not.
422     if (OpToken.isOneOf(tok::comma, tok::greater, tok::greatergreater,
423                         tok::greatergreatergreater) &&
424         checkPotentialAngleBracketDelimiter(OpToken))
425       return ExprError();
426 
427     // Bail out when encountering a comma followed by a token which can't
428     // possibly be the start of an expression. For instance:
429     //   int f() { return 1, }
430     // We can't do this before consuming the comma, because
431     // isNotExpressionStart() looks at the token stream.
432     if (OpToken.is(tok::comma) && isNotExpressionStart()) {
433       PP.EnterToken(Tok, /*IsReinject*/true);
434       Tok = OpToken;
435       return LHS;
436     }
437 
438     // If the next token is an ellipsis, then this is a fold-expression. Leave
439     // it alone so we can handle it in the paren expression.
440     if (isFoldOperator(NextTokPrec) && Tok.is(tok::ellipsis)) {
441       // FIXME: We can't check this via lookahead before we consume the token
442       // because that tickles a lexer bug.
443       PP.EnterToken(Tok, /*IsReinject*/true);
444       Tok = OpToken;
445       return LHS;
446     }
447 
448     // In Objective-C++, alternative operator tokens can be used as keyword args
449     // in message expressions. Unconsume the token so that it can reinterpreted
450     // as an identifier in ParseObjCMessageExpressionBody. i.e., we support:
451     //   [foo meth:0 and:0];
452     //   [foo not_eq];
453     if (getLangOpts().ObjC && getLangOpts().CPlusPlus &&
454         Tok.isOneOf(tok::colon, tok::r_square) &&
455         OpToken.getIdentifierInfo() != nullptr) {
456       PP.EnterToken(Tok, /*IsReinject*/true);
457       Tok = OpToken;
458       return LHS;
459     }
460 
461     // Special case handling for the ternary operator.
462     ExprResult TernaryMiddle(true);
463     if (NextTokPrec == prec::Conditional) {
464       if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
465         // Parse a braced-init-list here for error recovery purposes.
466         SourceLocation BraceLoc = Tok.getLocation();
467         TernaryMiddle = ParseBraceInitializer();
468         if (!TernaryMiddle.isInvalid()) {
469           Diag(BraceLoc, diag::err_init_list_bin_op)
470               << /*RHS*/ 1 << PP.getSpelling(OpToken)
471               << Actions.getExprRange(TernaryMiddle.get());
472           TernaryMiddle = ExprError();
473         }
474       } else if (Tok.isNot(tok::colon)) {
475         // Don't parse FOO:BAR as if it were a typo for FOO::BAR.
476         ColonProtectionRAIIObject X(*this);
477 
478         // Handle this production specially:
479         //   logical-OR-expression '?' expression ':' conditional-expression
480         // In particular, the RHS of the '?' is 'expression', not
481         // 'logical-OR-expression' as we might expect.
482         TernaryMiddle = ParseExpression();
483       } else {
484         // Special case handling of "X ? Y : Z" where Y is empty:
485         //   logical-OR-expression '?' ':' conditional-expression   [GNU]
486         TernaryMiddle = nullptr;
487         Diag(Tok, diag::ext_gnu_conditional_expr);
488       }
489 
490       if (TernaryMiddle.isInvalid()) {
491         Actions.CorrectDelayedTyposInExpr(LHS);
492         LHS = ExprError();
493         TernaryMiddle = nullptr;
494       }
495 
496       if (!TryConsumeToken(tok::colon, ColonLoc)) {
497         // Otherwise, we're missing a ':'.  Assume that this was a typo that
498         // the user forgot. If we're not in a macro expansion, we can suggest
499         // a fixit hint. If there were two spaces before the current token,
500         // suggest inserting the colon in between them, otherwise insert ": ".
501         SourceLocation FILoc = Tok.getLocation();
502         const char *FIText = ": ";
503         const SourceManager &SM = PP.getSourceManager();
504         if (FILoc.isFileID() || PP.isAtStartOfMacroExpansion(FILoc, &FILoc)) {
505           assert(FILoc.isFileID());
506           bool IsInvalid = false;
507           const char *SourcePtr =
508             SM.getCharacterData(FILoc.getLocWithOffset(-1), &IsInvalid);
509           if (!IsInvalid && *SourcePtr == ' ') {
510             SourcePtr =
511               SM.getCharacterData(FILoc.getLocWithOffset(-2), &IsInvalid);
512             if (!IsInvalid && *SourcePtr == ' ') {
513               FILoc = FILoc.getLocWithOffset(-1);
514               FIText = ":";
515             }
516           }
517         }
518 
519         Diag(Tok, diag::err_expected)
520             << tok::colon << FixItHint::CreateInsertion(FILoc, FIText);
521         Diag(OpToken, diag::note_matching) << tok::question;
522         ColonLoc = Tok.getLocation();
523       }
524     }
525 
526     PreferredType.enterBinary(Actions, Tok.getLocation(), LHS.get(),
527                               OpToken.getKind());
528     // Parse another leaf here for the RHS of the operator.
529     // ParseCastExpression works here because all RHS expressions in C have it
530     // as a prefix, at least. However, in C++, an assignment-expression could
531     // be a throw-expression, which is not a valid cast-expression.
532     // Therefore we need some special-casing here.
533     // Also note that the third operand of the conditional operator is
534     // an assignment-expression in C++, and in C++11, we can have a
535     // braced-init-list on the RHS of an assignment. For better diagnostics,
536     // parse as if we were allowed braced-init-lists everywhere, and check that
537     // they only appear on the RHS of assignments later.
538     ExprResult RHS;
539     bool RHSIsInitList = false;
540     if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
541       RHS = ParseBraceInitializer();
542       RHSIsInitList = true;
543     } else if (getLangOpts().CPlusPlus && NextTokPrec <= prec::Conditional)
544       RHS = ParseAssignmentExpression();
545     else
546       RHS = ParseCastExpression(AnyCastExpr);
547 
548     if (RHS.isInvalid()) {
549       // FIXME: Errors generated by the delayed typo correction should be
550       // printed before errors from parsing the RHS, not after.
551       Actions.CorrectDelayedTyposInExpr(LHS);
552       if (TernaryMiddle.isUsable())
553         TernaryMiddle = Actions.CorrectDelayedTyposInExpr(TernaryMiddle);
554       LHS = ExprError();
555     }
556 
557     // Remember the precedence of this operator and get the precedence of the
558     // operator immediately to the right of the RHS.
559     prec::Level ThisPrec = NextTokPrec;
560     NextTokPrec = getBinOpPrecedence(Tok.getKind(), GreaterThanIsOperator,
561                                      getLangOpts().CPlusPlus11);
562 
563     // Assignment and conditional expressions are right-associative.
564     bool isRightAssoc = ThisPrec == prec::Conditional ||
565                         ThisPrec == prec::Assignment;
566 
567     // Get the precedence of the operator to the right of the RHS.  If it binds
568     // more tightly with RHS than we do, evaluate it completely first.
569     if (ThisPrec < NextTokPrec ||
570         (ThisPrec == NextTokPrec && isRightAssoc)) {
571       if (!RHS.isInvalid() && RHSIsInitList) {
572         Diag(Tok, diag::err_init_list_bin_op)
573           << /*LHS*/0 << PP.getSpelling(Tok) << Actions.getExprRange(RHS.get());
574         RHS = ExprError();
575       }
576       // If this is left-associative, only parse things on the RHS that bind
577       // more tightly than the current operator.  If it is left-associative, it
578       // is okay, to bind exactly as tightly.  For example, compile A=B=C=D as
579       // A=(B=(C=D)), where each paren is a level of recursion here.
580       // The function takes ownership of the RHS.
581       RHS = ParseRHSOfBinaryExpression(RHS,
582                             static_cast<prec::Level>(ThisPrec + !isRightAssoc));
583       RHSIsInitList = false;
584 
585       if (RHS.isInvalid()) {
586         // FIXME: Errors generated by the delayed typo correction should be
587         // printed before errors from ParseRHSOfBinaryExpression, not after.
588         Actions.CorrectDelayedTyposInExpr(LHS);
589         if (TernaryMiddle.isUsable())
590           TernaryMiddle = Actions.CorrectDelayedTyposInExpr(TernaryMiddle);
591         LHS = ExprError();
592       }
593 
594       NextTokPrec = getBinOpPrecedence(Tok.getKind(), GreaterThanIsOperator,
595                                        getLangOpts().CPlusPlus11);
596     }
597 
598     if (!RHS.isInvalid() && RHSIsInitList) {
599       if (ThisPrec == prec::Assignment) {
600         Diag(OpToken, diag::warn_cxx98_compat_generalized_initializer_lists)
601           << Actions.getExprRange(RHS.get());
602       } else if (ColonLoc.isValid()) {
603         Diag(ColonLoc, diag::err_init_list_bin_op)
604           << /*RHS*/1 << ":"
605           << Actions.getExprRange(RHS.get());
606         LHS = ExprError();
607       } else {
608         Diag(OpToken, diag::err_init_list_bin_op)
609           << /*RHS*/1 << PP.getSpelling(OpToken)
610           << Actions.getExprRange(RHS.get());
611         LHS = ExprError();
612       }
613     }
614 
615     ExprResult OrigLHS = LHS;
616     if (!LHS.isInvalid()) {
617       // Combine the LHS and RHS into the LHS (e.g. build AST).
618       if (TernaryMiddle.isInvalid()) {
619         // If we're using '>>' as an operator within a template
620         // argument list (in C++98), suggest the addition of
621         // parentheses so that the code remains well-formed in C++0x.
622         if (!GreaterThanIsOperator && OpToken.is(tok::greatergreater))
623           SuggestParentheses(OpToken.getLocation(),
624                              diag::warn_cxx11_right_shift_in_template_arg,
625                          SourceRange(Actions.getExprRange(LHS.get()).getBegin(),
626                                      Actions.getExprRange(RHS.get()).getEnd()));
627 
628         ExprResult BinOp =
629             Actions.ActOnBinOp(getCurScope(), OpToken.getLocation(),
630                                OpToken.getKind(), LHS.get(), RHS.get());
631         if (BinOp.isInvalid())
632           BinOp = Actions.CreateRecoveryExpr(LHS.get()->getBeginLoc(),
633                                              RHS.get()->getEndLoc(),
634                                              {LHS.get(), RHS.get()});
635 
636         LHS = BinOp;
637       } else {
638         ExprResult CondOp = Actions.ActOnConditionalOp(
639             OpToken.getLocation(), ColonLoc, LHS.get(), TernaryMiddle.get(),
640             RHS.get());
641         if (CondOp.isInvalid()) {
642           std::vector<clang::Expr *> Args;
643           // TernaryMiddle can be null for the GNU conditional expr extension.
644           if (TernaryMiddle.get())
645             Args = {LHS.get(), TernaryMiddle.get(), RHS.get()};
646           else
647             Args = {LHS.get(), RHS.get()};
648           CondOp = Actions.CreateRecoveryExpr(LHS.get()->getBeginLoc(),
649                                               RHS.get()->getEndLoc(), Args);
650         }
651 
652         LHS = CondOp;
653       }
654       // In this case, ActOnBinOp or ActOnConditionalOp performed the
655       // CorrectDelayedTyposInExpr check.
656       if (!getLangOpts().CPlusPlus)
657         continue;
658     }
659 
660     // Ensure potential typos aren't left undiagnosed.
661     if (LHS.isInvalid()) {
662       Actions.CorrectDelayedTyposInExpr(OrigLHS);
663       Actions.CorrectDelayedTyposInExpr(TernaryMiddle);
664       Actions.CorrectDelayedTyposInExpr(RHS);
665     }
666   }
667 }
668 
669 /// Parse a cast-expression, unary-expression or primary-expression, based
670 /// on \p ExprType.
671 ///
672 /// \p isAddressOfOperand exists because an id-expression that is the
673 /// operand of address-of gets special treatment due to member pointers.
674 ///
ParseCastExpression(CastParseKind ParseKind,bool isAddressOfOperand,TypeCastState isTypeCast,bool isVectorLiteral,bool * NotPrimaryExpression)675 ExprResult Parser::ParseCastExpression(CastParseKind ParseKind,
676                                        bool isAddressOfOperand,
677                                        TypeCastState isTypeCast,
678                                        bool isVectorLiteral,
679                                        bool *NotPrimaryExpression) {
680   bool NotCastExpr;
681   ExprResult Res = ParseCastExpression(ParseKind,
682                                        isAddressOfOperand,
683                                        NotCastExpr,
684                                        isTypeCast,
685                                        isVectorLiteral,
686                                        NotPrimaryExpression);
687   if (NotCastExpr)
688     Diag(Tok, diag::err_expected_expression);
689   return Res;
690 }
691 
692 namespace {
693 class CastExpressionIdValidator final : public CorrectionCandidateCallback {
694  public:
CastExpressionIdValidator(Token Next,bool AllowTypes,bool AllowNonTypes)695   CastExpressionIdValidator(Token Next, bool AllowTypes, bool AllowNonTypes)
696       : NextToken(Next), AllowNonTypes(AllowNonTypes) {
697     WantTypeSpecifiers = WantFunctionLikeCasts = AllowTypes;
698   }
699 
ValidateCandidate(const TypoCorrection & candidate)700   bool ValidateCandidate(const TypoCorrection &candidate) override {
701     NamedDecl *ND = candidate.getCorrectionDecl();
702     if (!ND)
703       return candidate.isKeyword();
704 
705     if (isa<TypeDecl>(ND))
706       return WantTypeSpecifiers;
707 
708     if (!AllowNonTypes || !CorrectionCandidateCallback::ValidateCandidate(candidate))
709       return false;
710 
711     if (!NextToken.isOneOf(tok::equal, tok::arrow, tok::period))
712       return true;
713 
714     for (auto *C : candidate) {
715       NamedDecl *ND = C->getUnderlyingDecl();
716       if (isa<ValueDecl>(ND) && !isa<FunctionDecl>(ND))
717         return true;
718     }
719     return false;
720   }
721 
clone()722   std::unique_ptr<CorrectionCandidateCallback> clone() override {
723     return std::make_unique<CastExpressionIdValidator>(*this);
724   }
725 
726  private:
727   Token NextToken;
728   bool AllowNonTypes;
729 };
730 }
731 
732 /// Parse a cast-expression, or, if \pisUnaryExpression is true, parse
733 /// a unary-expression.
734 ///
735 /// \p isAddressOfOperand exists because an id-expression that is the operand
736 /// of address-of gets special treatment due to member pointers. NotCastExpr
737 /// is set to true if the token is not the start of a cast-expression, and no
738 /// diagnostic is emitted in this case and no tokens are consumed.
739 ///
740 /// \verbatim
741 ///       cast-expression: [C99 6.5.4]
742 ///         unary-expression
743 ///         '(' type-name ')' cast-expression
744 ///
745 ///       unary-expression:  [C99 6.5.3]
746 ///         postfix-expression
747 ///         '++' unary-expression
748 ///         '--' unary-expression
749 /// [Coro]  'co_await' cast-expression
750 ///         unary-operator cast-expression
751 ///         'sizeof' unary-expression
752 ///         'sizeof' '(' type-name ')'
753 /// [C++11] 'sizeof' '...' '(' identifier ')'
754 /// [GNU]   '__alignof' unary-expression
755 /// [GNU]   '__alignof' '(' type-name ')'
756 /// [C11]   '_Alignof' '(' type-name ')'
757 /// [C++11] 'alignof' '(' type-id ')'
758 /// [GNU]   '&&' identifier
759 /// [C++11] 'noexcept' '(' expression ')' [C++11 5.3.7]
760 /// [C++]   new-expression
761 /// [C++]   delete-expression
762 ///
763 ///       unary-operator: one of
764 ///         '&'  '*'  '+'  '-'  '~'  '!'
765 /// [GNU]   '__extension__'  '__real'  '__imag'
766 ///
767 ///       primary-expression: [C99 6.5.1]
768 /// [C99]   identifier
769 /// [C++]   id-expression
770 ///         constant
771 ///         string-literal
772 /// [C++]   boolean-literal  [C++ 2.13.5]
773 /// [C++11] 'nullptr'        [C++11 2.14.7]
774 /// [C++11] user-defined-literal
775 ///         '(' expression ')'
776 /// [C11]   generic-selection
777 /// [C++2a] requires-expression
778 ///         '__func__'        [C99 6.4.2.2]
779 /// [GNU]   '__FUNCTION__'
780 /// [MS]    '__FUNCDNAME__'
781 /// [MS]    'L__FUNCTION__'
782 /// [MS]    '__FUNCSIG__'
783 /// [MS]    'L__FUNCSIG__'
784 /// [GNU]   '__PRETTY_FUNCTION__'
785 /// [GNU]   '(' compound-statement ')'
786 /// [GNU]   '__builtin_va_arg' '(' assignment-expression ',' type-name ')'
787 /// [GNU]   '__builtin_offsetof' '(' type-name ',' offsetof-member-designator')'
788 /// [GNU]   '__builtin_choose_expr' '(' assign-expr ',' assign-expr ','
789 ///                                     assign-expr ')'
790 /// [GNU]   '__builtin_FILE' '(' ')'
791 /// [GNU]   '__builtin_FUNCTION' '(' ')'
792 /// [GNU]   '__builtin_LINE' '(' ')'
793 /// [CLANG] '__builtin_COLUMN' '(' ')'
794 /// [GNU]   '__builtin_types_compatible_p' '(' type-name ',' type-name ')'
795 /// [GNU]   '__null'
796 /// [OBJC]  '[' objc-message-expr ']'
797 /// [OBJC]  '\@selector' '(' objc-selector-arg ')'
798 /// [OBJC]  '\@protocol' '(' identifier ')'
799 /// [OBJC]  '\@encode' '(' type-name ')'
800 /// [OBJC]  objc-string-literal
801 /// [C++]   simple-type-specifier '(' expression-list[opt] ')'      [C++ 5.2.3]
802 /// [C++11] simple-type-specifier braced-init-list                  [C++11 5.2.3]
803 /// [C++]   typename-specifier '(' expression-list[opt] ')'         [C++ 5.2.3]
804 /// [C++11] typename-specifier braced-init-list                     [C++11 5.2.3]
805 /// [C++]   'const_cast' '<' type-name '>' '(' expression ')'       [C++ 5.2p1]
806 /// [C++]   'dynamic_cast' '<' type-name '>' '(' expression ')'     [C++ 5.2p1]
807 /// [C++]   'reinterpret_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
808 /// [C++]   'static_cast' '<' type-name '>' '(' expression ')'      [C++ 5.2p1]
809 /// [C++]   'typeid' '(' expression ')'                             [C++ 5.2p1]
810 /// [C++]   'typeid' '(' type-id ')'                                [C++ 5.2p1]
811 /// [C++]   'this'          [C++ 9.3.2]
812 /// [G++]   unary-type-trait '(' type-id ')'
813 /// [G++]   binary-type-trait '(' type-id ',' type-id ')'           [TODO]
814 /// [EMBT]  array-type-trait '(' type-id ',' integer ')'
815 /// [clang] '^' block-literal
816 ///
817 ///       constant: [C99 6.4.4]
818 ///         integer-constant
819 ///         floating-constant
820 ///         enumeration-constant -> identifier
821 ///         character-constant
822 ///
823 ///       id-expression: [C++ 5.1]
824 ///                   unqualified-id
825 ///                   qualified-id
826 ///
827 ///       unqualified-id: [C++ 5.1]
828 ///                   identifier
829 ///                   operator-function-id
830 ///                   conversion-function-id
831 ///                   '~' class-name
832 ///                   template-id
833 ///
834 ///       new-expression: [C++ 5.3.4]
835 ///                   '::'[opt] 'new' new-placement[opt] new-type-id
836 ///                                     new-initializer[opt]
837 ///                   '::'[opt] 'new' new-placement[opt] '(' type-id ')'
838 ///                                     new-initializer[opt]
839 ///
840 ///       delete-expression: [C++ 5.3.5]
841 ///                   '::'[opt] 'delete' cast-expression
842 ///                   '::'[opt] 'delete' '[' ']' cast-expression
843 ///
844 /// [GNU/Embarcadero] unary-type-trait:
845 ///                   '__is_arithmetic'
846 ///                   '__is_floating_point'
847 ///                   '__is_integral'
848 ///                   '__is_lvalue_expr'
849 ///                   '__is_rvalue_expr'
850 ///                   '__is_complete_type'
851 ///                   '__is_void'
852 ///                   '__is_array'
853 ///                   '__is_function'
854 ///                   '__is_reference'
855 ///                   '__is_lvalue_reference'
856 ///                   '__is_rvalue_reference'
857 ///                   '__is_fundamental'
858 ///                   '__is_object'
859 ///                   '__is_scalar'
860 ///                   '__is_compound'
861 ///                   '__is_pointer'
862 ///                   '__is_member_object_pointer'
863 ///                   '__is_member_function_pointer'
864 ///                   '__is_member_pointer'
865 ///                   '__is_const'
866 ///                   '__is_volatile'
867 ///                   '__is_trivial'
868 ///                   '__is_standard_layout'
869 ///                   '__is_signed'
870 ///                   '__is_unsigned'
871 ///
872 /// [GNU] unary-type-trait:
873 ///                   '__has_nothrow_assign'
874 ///                   '__has_nothrow_copy'
875 ///                   '__has_nothrow_constructor'
876 ///                   '__has_trivial_assign'                  [TODO]
877 ///                   '__has_trivial_copy'                    [TODO]
878 ///                   '__has_trivial_constructor'
879 ///                   '__has_trivial_destructor'
880 ///                   '__has_virtual_destructor'
881 ///                   '__is_abstract'                         [TODO]
882 ///                   '__is_class'
883 ///                   '__is_empty'                            [TODO]
884 ///                   '__is_enum'
885 ///                   '__is_final'
886 ///                   '__is_pod'
887 ///                   '__is_polymorphic'
888 ///                   '__is_sealed'                           [MS]
889 ///                   '__is_trivial'
890 ///                   '__is_union'
891 ///                   '__has_unique_object_representations'
892 ///
893 /// [Clang] unary-type-trait:
894 ///                   '__is_aggregate'
895 ///                   '__trivially_copyable'
896 ///
897 ///       binary-type-trait:
898 /// [GNU]             '__is_base_of'
899 /// [MS]              '__is_convertible_to'
900 ///                   '__is_convertible'
901 ///                   '__is_same'
902 ///
903 /// [Embarcadero] array-type-trait:
904 ///                   '__array_rank'
905 ///                   '__array_extent'
906 ///
907 /// [Embarcadero] expression-trait:
908 ///                   '__is_lvalue_expr'
909 ///                   '__is_rvalue_expr'
910 /// \endverbatim
911 ///
ParseCastExpression(CastParseKind ParseKind,bool isAddressOfOperand,bool & NotCastExpr,TypeCastState isTypeCast,bool isVectorLiteral,bool * NotPrimaryExpression)912 ExprResult Parser::ParseCastExpression(CastParseKind ParseKind,
913                                        bool isAddressOfOperand,
914                                        bool &NotCastExpr,
915                                        TypeCastState isTypeCast,
916                                        bool isVectorLiteral,
917                                        bool *NotPrimaryExpression) {
918   ExprResult Res;
919   tok::TokenKind SavedKind = Tok.getKind();
920   auto SavedType = PreferredType;
921   NotCastExpr = false;
922 
923   // Are postfix-expression suffix operators permitted after this
924   // cast-expression? If not, and we find some, we'll parse them anyway and
925   // diagnose them.
926   bool AllowSuffix = true;
927 
928   // This handles all of cast-expression, unary-expression, postfix-expression,
929   // and primary-expression.  We handle them together like this for efficiency
930   // and to simplify handling of an expression starting with a '(' token: which
931   // may be one of a parenthesized expression, cast-expression, compound literal
932   // expression, or statement expression.
933   //
934   // If the parsed tokens consist of a primary-expression, the cases below
935   // break out of the switch;  at the end we call ParsePostfixExpressionSuffix
936   // to handle the postfix expression suffixes.  Cases that cannot be followed
937   // by postfix exprs should set AllowSuffix to false.
938   switch (SavedKind) {
939   case tok::l_paren: {
940     // If this expression is limited to being a unary-expression, the paren can
941     // not start a cast expression.
942     ParenParseOption ParenExprType;
943     switch (ParseKind) {
944       case CastParseKind::UnaryExprOnly:
945         if (!getLangOpts().CPlusPlus)
946           ParenExprType = CompoundLiteral;
947         LLVM_FALLTHROUGH;
948       case CastParseKind::AnyCastExpr:
949         ParenExprType = ParenParseOption::CastExpr;
950         break;
951       case CastParseKind::PrimaryExprOnly:
952         ParenExprType = FoldExpr;
953         break;
954     }
955     ParsedType CastTy;
956     SourceLocation RParenLoc;
957     Res = ParseParenExpression(ParenExprType, false/*stopIfCastExr*/,
958                                isTypeCast == IsTypeCast, CastTy, RParenLoc);
959 
960     // FIXME: What should we do if a vector literal is followed by a
961     // postfix-expression suffix? Usually postfix operators are permitted on
962     // literals.
963     if (isVectorLiteral)
964       return Res;
965 
966     switch (ParenExprType) {
967     case SimpleExpr:   break;    // Nothing else to do.
968     case CompoundStmt: break;  // Nothing else to do.
969     case CompoundLiteral:
970       // We parsed '(' type-name ')' '{' ... '}'.  If any suffixes of
971       // postfix-expression exist, parse them now.
972       break;
973     case CastExpr:
974       // We have parsed the cast-expression and no postfix-expr pieces are
975       // following.
976       return Res;
977     case FoldExpr:
978       // We only parsed a fold-expression. There might be postfix-expr pieces
979       // afterwards; parse them now.
980       break;
981     }
982 
983     break;
984   }
985 
986     // primary-expression
987   case tok::numeric_constant:
988     // constant: integer-constant
989     // constant: floating-constant
990 
991     Res = Actions.ActOnNumericConstant(Tok, /*UDLScope*/getCurScope());
992     ConsumeToken();
993     break;
994 
995   case tok::kw_true:
996   case tok::kw_false:
997     Res = ParseCXXBoolLiteral();
998     break;
999 
1000   case tok::kw___objc_yes:
1001   case tok::kw___objc_no:
1002     Res = ParseObjCBoolLiteral();
1003     break;
1004 
1005   case tok::kw_nullptr:
1006     Diag(Tok, diag::warn_cxx98_compat_nullptr);
1007     Res = Actions.ActOnCXXNullPtrLiteral(ConsumeToken());
1008     break;
1009 
1010   case tok::annot_primary_expr:
1011   case tok::annot_overload_set:
1012     Res = getExprAnnotation(Tok);
1013     if (!Res.isInvalid() && Tok.getKind() == tok::annot_overload_set)
1014       Res = Actions.ActOnNameClassifiedAsOverloadSet(getCurScope(), Res.get());
1015     ConsumeAnnotationToken();
1016     if (!Res.isInvalid() && Tok.is(tok::less))
1017       checkPotentialAngleBracket(Res);
1018     break;
1019 
1020   case tok::annot_non_type:
1021   case tok::annot_non_type_dependent:
1022   case tok::annot_non_type_undeclared: {
1023     CXXScopeSpec SS;
1024     Token Replacement;
1025     Res = tryParseCXXIdExpression(SS, isAddressOfOperand, Replacement);
1026     assert(!Res.isUnset() &&
1027            "should not perform typo correction on annotation token");
1028     break;
1029   }
1030 
1031   case tok::kw___super:
1032   case tok::kw_decltype:
1033     // Annotate the token and tail recurse.
1034     if (TryAnnotateTypeOrScopeToken())
1035       return ExprError();
1036     assert(Tok.isNot(tok::kw_decltype) && Tok.isNot(tok::kw___super));
1037     return ParseCastExpression(ParseKind, isAddressOfOperand, isTypeCast,
1038                                isVectorLiteral, NotPrimaryExpression);
1039 
1040   case tok::identifier: {      // primary-expression: identifier
1041                                // unqualified-id: identifier
1042                                // constant: enumeration-constant
1043     // Turn a potentially qualified name into a annot_typename or
1044     // annot_cxxscope if it would be valid.  This handles things like x::y, etc.
1045     if (getLangOpts().CPlusPlus) {
1046       // Avoid the unnecessary parse-time lookup in the common case
1047       // where the syntax forbids a type.
1048       const Token &Next = NextToken();
1049 
1050       // If this identifier was reverted from a token ID, and the next token
1051       // is a parenthesis, this is likely to be a use of a type trait. Check
1052       // those tokens.
1053       if (Next.is(tok::l_paren) &&
1054           Tok.is(tok::identifier) &&
1055           Tok.getIdentifierInfo()->hasRevertedTokenIDToIdentifier()) {
1056         IdentifierInfo *II = Tok.getIdentifierInfo();
1057         // Build up the mapping of revertible type traits, for future use.
1058         if (RevertibleTypeTraits.empty()) {
1059 #define RTT_JOIN(X,Y) X##Y
1060 #define REVERTIBLE_TYPE_TRAIT(Name)                         \
1061           RevertibleTypeTraits[PP.getIdentifierInfo(#Name)] \
1062             = RTT_JOIN(tok::kw_,Name)
1063 
1064           REVERTIBLE_TYPE_TRAIT(__is_abstract);
1065           REVERTIBLE_TYPE_TRAIT(__is_aggregate);
1066           REVERTIBLE_TYPE_TRAIT(__is_arithmetic);
1067           REVERTIBLE_TYPE_TRAIT(__is_array);
1068           REVERTIBLE_TYPE_TRAIT(__is_assignable);
1069           REVERTIBLE_TYPE_TRAIT(__is_base_of);
1070           REVERTIBLE_TYPE_TRAIT(__is_class);
1071           REVERTIBLE_TYPE_TRAIT(__is_complete_type);
1072           REVERTIBLE_TYPE_TRAIT(__is_compound);
1073           REVERTIBLE_TYPE_TRAIT(__is_const);
1074           REVERTIBLE_TYPE_TRAIT(__is_constructible);
1075           REVERTIBLE_TYPE_TRAIT(__is_convertible);
1076           REVERTIBLE_TYPE_TRAIT(__is_convertible_to);
1077           REVERTIBLE_TYPE_TRAIT(__is_destructible);
1078           REVERTIBLE_TYPE_TRAIT(__is_empty);
1079           REVERTIBLE_TYPE_TRAIT(__is_enum);
1080           REVERTIBLE_TYPE_TRAIT(__is_floating_point);
1081           REVERTIBLE_TYPE_TRAIT(__is_final);
1082           REVERTIBLE_TYPE_TRAIT(__is_function);
1083           REVERTIBLE_TYPE_TRAIT(__is_fundamental);
1084           REVERTIBLE_TYPE_TRAIT(__is_integral);
1085           REVERTIBLE_TYPE_TRAIT(__is_interface_class);
1086           REVERTIBLE_TYPE_TRAIT(__is_literal);
1087           REVERTIBLE_TYPE_TRAIT(__is_lvalue_expr);
1088           REVERTIBLE_TYPE_TRAIT(__is_lvalue_reference);
1089           REVERTIBLE_TYPE_TRAIT(__is_member_function_pointer);
1090           REVERTIBLE_TYPE_TRAIT(__is_member_object_pointer);
1091           REVERTIBLE_TYPE_TRAIT(__is_member_pointer);
1092           REVERTIBLE_TYPE_TRAIT(__is_nothrow_assignable);
1093           REVERTIBLE_TYPE_TRAIT(__is_nothrow_constructible);
1094           REVERTIBLE_TYPE_TRAIT(__is_nothrow_destructible);
1095           REVERTIBLE_TYPE_TRAIT(__is_object);
1096           REVERTIBLE_TYPE_TRAIT(__is_pod);
1097           REVERTIBLE_TYPE_TRAIT(__is_pointer);
1098           REVERTIBLE_TYPE_TRAIT(__is_polymorphic);
1099           REVERTIBLE_TYPE_TRAIT(__is_reference);
1100           REVERTIBLE_TYPE_TRAIT(__is_rvalue_expr);
1101           REVERTIBLE_TYPE_TRAIT(__is_rvalue_reference);
1102           REVERTIBLE_TYPE_TRAIT(__is_same);
1103           REVERTIBLE_TYPE_TRAIT(__is_scalar);
1104           REVERTIBLE_TYPE_TRAIT(__is_sealed);
1105           REVERTIBLE_TYPE_TRAIT(__is_signed);
1106           REVERTIBLE_TYPE_TRAIT(__is_standard_layout);
1107           REVERTIBLE_TYPE_TRAIT(__is_trivial);
1108           REVERTIBLE_TYPE_TRAIT(__is_trivially_assignable);
1109           REVERTIBLE_TYPE_TRAIT(__is_trivially_constructible);
1110           REVERTIBLE_TYPE_TRAIT(__is_trivially_copyable);
1111           REVERTIBLE_TYPE_TRAIT(__is_union);
1112           REVERTIBLE_TYPE_TRAIT(__is_unsigned);
1113           REVERTIBLE_TYPE_TRAIT(__is_void);
1114           REVERTIBLE_TYPE_TRAIT(__is_volatile);
1115 #undef REVERTIBLE_TYPE_TRAIT
1116 #undef RTT_JOIN
1117         }
1118 
1119         // If we find that this is in fact the name of a type trait,
1120         // update the token kind in place and parse again to treat it as
1121         // the appropriate kind of type trait.
1122         llvm::SmallDenseMap<IdentifierInfo *, tok::TokenKind>::iterator Known
1123           = RevertibleTypeTraits.find(II);
1124         if (Known != RevertibleTypeTraits.end()) {
1125           Tok.setKind(Known->second);
1126           return ParseCastExpression(ParseKind, isAddressOfOperand,
1127                                      NotCastExpr, isTypeCast,
1128                                      isVectorLiteral, NotPrimaryExpression);
1129         }
1130       }
1131 
1132       if ((!ColonIsSacred && Next.is(tok::colon)) ||
1133           Next.isOneOf(tok::coloncolon, tok::less, tok::l_paren,
1134                        tok::l_brace)) {
1135         // If TryAnnotateTypeOrScopeToken annotates the token, tail recurse.
1136         if (TryAnnotateTypeOrScopeToken())
1137           return ExprError();
1138         if (!Tok.is(tok::identifier))
1139           return ParseCastExpression(ParseKind, isAddressOfOperand,
1140                                      NotCastExpr, isTypeCast,
1141                                      isVectorLiteral,
1142                                      NotPrimaryExpression);
1143       }
1144     }
1145 
1146     // Consume the identifier so that we can see if it is followed by a '(' or
1147     // '.'.
1148     IdentifierInfo &II = *Tok.getIdentifierInfo();
1149     SourceLocation ILoc = ConsumeToken();
1150 
1151     // Support 'Class.property' and 'super.property' notation.
1152     if (getLangOpts().ObjC && Tok.is(tok::period) &&
1153         (Actions.getTypeName(II, ILoc, getCurScope()) ||
1154          // Allow the base to be 'super' if in an objc-method.
1155          (&II == Ident_super && getCurScope()->isInObjcMethodScope()))) {
1156       ConsumeToken();
1157 
1158       if (Tok.is(tok::code_completion) && &II != Ident_super) {
1159         cutOffParsing();
1160         Actions.CodeCompleteObjCClassPropertyRefExpr(
1161             getCurScope(), II, ILoc, ExprStatementTokLoc == ILoc);
1162         return ExprError();
1163       }
1164       // Allow either an identifier or the keyword 'class' (in C++).
1165       if (Tok.isNot(tok::identifier) &&
1166           !(getLangOpts().CPlusPlus && Tok.is(tok::kw_class))) {
1167         Diag(Tok, diag::err_expected_property_name);
1168         return ExprError();
1169       }
1170       IdentifierInfo &PropertyName = *Tok.getIdentifierInfo();
1171       SourceLocation PropertyLoc = ConsumeToken();
1172 
1173       Res = Actions.ActOnClassPropertyRefExpr(II, PropertyName,
1174                                               ILoc, PropertyLoc);
1175       break;
1176     }
1177 
1178     // In an Objective-C method, if we have "super" followed by an identifier,
1179     // the token sequence is ill-formed. However, if there's a ':' or ']' after
1180     // that identifier, this is probably a message send with a missing open
1181     // bracket. Treat it as such.
1182     if (getLangOpts().ObjC && &II == Ident_super && !InMessageExpression &&
1183         getCurScope()->isInObjcMethodScope() &&
1184         ((Tok.is(tok::identifier) &&
1185          (NextToken().is(tok::colon) || NextToken().is(tok::r_square))) ||
1186          Tok.is(tok::code_completion))) {
1187       Res = ParseObjCMessageExpressionBody(SourceLocation(), ILoc, nullptr,
1188                                            nullptr);
1189       break;
1190     }
1191 
1192     // If we have an Objective-C class name followed by an identifier
1193     // and either ':' or ']', this is an Objective-C class message
1194     // send that's missing the opening '['. Recovery
1195     // appropriately. Also take this path if we're performing code
1196     // completion after an Objective-C class name.
1197     if (getLangOpts().ObjC &&
1198         ((Tok.is(tok::identifier) && !InMessageExpression) ||
1199          Tok.is(tok::code_completion))) {
1200       const Token& Next = NextToken();
1201       if (Tok.is(tok::code_completion) ||
1202           Next.is(tok::colon) || Next.is(tok::r_square))
1203         if (ParsedType Typ = Actions.getTypeName(II, ILoc, getCurScope()))
1204           if (Typ.get()->isObjCObjectOrInterfaceType()) {
1205             // Fake up a Declarator to use with ActOnTypeName.
1206             DeclSpec DS(AttrFactory);
1207             DS.SetRangeStart(ILoc);
1208             DS.SetRangeEnd(ILoc);
1209             const char *PrevSpec = nullptr;
1210             unsigned DiagID;
1211             DS.SetTypeSpecType(TST_typename, ILoc, PrevSpec, DiagID, Typ,
1212                                Actions.getASTContext().getPrintingPolicy());
1213 
1214             Declarator DeclaratorInfo(DS, DeclaratorContext::TypeName);
1215             TypeResult Ty = Actions.ActOnTypeName(getCurScope(),
1216                                                   DeclaratorInfo);
1217             if (Ty.isInvalid())
1218               break;
1219 
1220             Res = ParseObjCMessageExpressionBody(SourceLocation(),
1221                                                  SourceLocation(),
1222                                                  Ty.get(), nullptr);
1223             break;
1224           }
1225     }
1226 
1227     // Make sure to pass down the right value for isAddressOfOperand.
1228     if (isAddressOfOperand && isPostfixExpressionSuffixStart())
1229       isAddressOfOperand = false;
1230 
1231     // Function designators are allowed to be undeclared (C99 6.5.1p2), so we
1232     // need to know whether or not this identifier is a function designator or
1233     // not.
1234     UnqualifiedId Name;
1235     CXXScopeSpec ScopeSpec;
1236     SourceLocation TemplateKWLoc;
1237     Token Replacement;
1238     CastExpressionIdValidator Validator(
1239         /*Next=*/Tok,
1240         /*AllowTypes=*/isTypeCast != NotTypeCast,
1241         /*AllowNonTypes=*/isTypeCast != IsTypeCast);
1242     Validator.IsAddressOfOperand = isAddressOfOperand;
1243     if (Tok.isOneOf(tok::periodstar, tok::arrowstar)) {
1244       Validator.WantExpressionKeywords = false;
1245       Validator.WantRemainingKeywords = false;
1246     } else {
1247       Validator.WantRemainingKeywords = Tok.isNot(tok::r_paren);
1248     }
1249     Name.setIdentifier(&II, ILoc);
1250     Res = Actions.ActOnIdExpression(
1251         getCurScope(), ScopeSpec, TemplateKWLoc, Name, Tok.is(tok::l_paren),
1252         isAddressOfOperand, &Validator,
1253         /*IsInlineAsmIdentifier=*/false,
1254         Tok.is(tok::r_paren) ? nullptr : &Replacement);
1255     if (!Res.isInvalid() && Res.isUnset()) {
1256       UnconsumeToken(Replacement);
1257       return ParseCastExpression(ParseKind, isAddressOfOperand,
1258                                  NotCastExpr, isTypeCast,
1259                                  /*isVectorLiteral=*/false,
1260                                  NotPrimaryExpression);
1261     }
1262     if (!Res.isInvalid() && Tok.is(tok::less))
1263       checkPotentialAngleBracket(Res);
1264     break;
1265   }
1266   case tok::char_constant:     // constant: character-constant
1267   case tok::wide_char_constant:
1268   case tok::utf8_char_constant:
1269   case tok::utf16_char_constant:
1270   case tok::utf32_char_constant:
1271     Res = Actions.ActOnCharacterConstant(Tok, /*UDLScope*/getCurScope());
1272     ConsumeToken();
1273     break;
1274   case tok::kw___func__:       // primary-expression: __func__ [C99 6.4.2.2]
1275   case tok::kw___FUNCTION__:   // primary-expression: __FUNCTION__ [GNU]
1276   case tok::kw___FUNCDNAME__:   // primary-expression: __FUNCDNAME__ [MS]
1277   case tok::kw___FUNCSIG__:     // primary-expression: __FUNCSIG__ [MS]
1278   case tok::kw_L__FUNCTION__:   // primary-expression: L__FUNCTION__ [MS]
1279   case tok::kw_L__FUNCSIG__:    // primary-expression: L__FUNCSIG__ [MS]
1280   case tok::kw___PRETTY_FUNCTION__:  // primary-expression: __P..Y_F..N__ [GNU]
1281     Res = Actions.ActOnPredefinedExpr(Tok.getLocation(), SavedKind);
1282     ConsumeToken();
1283     break;
1284   case tok::string_literal:    // primary-expression: string-literal
1285   case tok::wide_string_literal:
1286   case tok::utf8_string_literal:
1287   case tok::utf16_string_literal:
1288   case tok::utf32_string_literal:
1289     Res = ParseStringLiteralExpression(true);
1290     break;
1291   case tok::kw__Generic:   // primary-expression: generic-selection [C11 6.5.1]
1292     Res = ParseGenericSelectionExpression();
1293     break;
1294   case tok::kw___builtin_available:
1295     Res = ParseAvailabilityCheckExpr(Tok.getLocation());
1296     break;
1297   case tok::kw___builtin_va_arg:
1298   case tok::kw___builtin_offsetof:
1299   case tok::kw___builtin_choose_expr:
1300   case tok::kw___builtin_astype: // primary-expression: [OCL] as_type()
1301   case tok::kw___builtin_convertvector:
1302   case tok::kw___builtin_COLUMN:
1303   case tok::kw___builtin_FILE:
1304   case tok::kw___builtin_FUNCTION:
1305   case tok::kw___builtin_LINE:
1306     if (NotPrimaryExpression)
1307       *NotPrimaryExpression = true;
1308     // This parses the complete suffix; we can return early.
1309     return ParseBuiltinPrimaryExpression();
1310   case tok::kw___null:
1311     Res = Actions.ActOnGNUNullExpr(ConsumeToken());
1312     break;
1313 
1314   case tok::plusplus:      // unary-expression: '++' unary-expression [C99]
1315   case tok::minusminus: {  // unary-expression: '--' unary-expression [C99]
1316     if (NotPrimaryExpression)
1317       *NotPrimaryExpression = true;
1318     // C++ [expr.unary] has:
1319     //   unary-expression:
1320     //     ++ cast-expression
1321     //     -- cast-expression
1322     Token SavedTok = Tok;
1323     ConsumeToken();
1324 
1325     PreferredType.enterUnary(Actions, Tok.getLocation(), SavedTok.getKind(),
1326                              SavedTok.getLocation());
1327     // One special case is implicitly handled here: if the preceding tokens are
1328     // an ambiguous cast expression, such as "(T())++", then we recurse to
1329     // determine whether the '++' is prefix or postfix.
1330     Res = ParseCastExpression(getLangOpts().CPlusPlus ?
1331                                   UnaryExprOnly : AnyCastExpr,
1332                               /*isAddressOfOperand*/false, NotCastExpr,
1333                               NotTypeCast);
1334     if (NotCastExpr) {
1335       // If we return with NotCastExpr = true, we must not consume any tokens,
1336       // so put the token back where we found it.
1337       assert(Res.isInvalid());
1338       UnconsumeToken(SavedTok);
1339       return ExprError();
1340     }
1341     if (!Res.isInvalid()) {
1342       Expr *Arg = Res.get();
1343       Res = Actions.ActOnUnaryOp(getCurScope(), SavedTok.getLocation(),
1344                                  SavedKind, Arg);
1345       if (Res.isInvalid())
1346         Res = Actions.CreateRecoveryExpr(SavedTok.getLocation(),
1347                                          Arg->getEndLoc(), Arg);
1348     }
1349     return Res;
1350   }
1351   case tok::amp: {         // unary-expression: '&' cast-expression
1352     if (NotPrimaryExpression)
1353       *NotPrimaryExpression = true;
1354     // Special treatment because of member pointers
1355     SourceLocation SavedLoc = ConsumeToken();
1356     PreferredType.enterUnary(Actions, Tok.getLocation(), tok::amp, SavedLoc);
1357     Res = ParseCastExpression(AnyCastExpr, true);
1358     if (!Res.isInvalid()) {
1359       Expr *Arg = Res.get();
1360       Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Arg);
1361       if (Res.isInvalid())
1362         Res = Actions.CreateRecoveryExpr(Tok.getLocation(), Arg->getEndLoc(),
1363                                          Arg);
1364     }
1365     return Res;
1366   }
1367 
1368   case tok::star:          // unary-expression: '*' cast-expression
1369   case tok::plus:          // unary-expression: '+' cast-expression
1370   case tok::minus:         // unary-expression: '-' cast-expression
1371   case tok::tilde:         // unary-expression: '~' cast-expression
1372   case tok::exclaim:       // unary-expression: '!' cast-expression
1373   case tok::kw___real:     // unary-expression: '__real' cast-expression [GNU]
1374   case tok::kw___imag: {   // unary-expression: '__imag' cast-expression [GNU]
1375     if (NotPrimaryExpression)
1376       *NotPrimaryExpression = true;
1377     SourceLocation SavedLoc = ConsumeToken();
1378     PreferredType.enterUnary(Actions, Tok.getLocation(), SavedKind, SavedLoc);
1379     Res = ParseCastExpression(AnyCastExpr);
1380     if (!Res.isInvalid()) {
1381       Expr *Arg = Res.get();
1382       Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Arg);
1383       if (Res.isInvalid())
1384         Res = Actions.CreateRecoveryExpr(SavedLoc, Arg->getEndLoc(), Arg);
1385     }
1386     return Res;
1387   }
1388 
1389   case tok::kw_co_await: {  // unary-expression: 'co_await' cast-expression
1390     if (NotPrimaryExpression)
1391       *NotPrimaryExpression = true;
1392     SourceLocation CoawaitLoc = ConsumeToken();
1393     Res = ParseCastExpression(AnyCastExpr);
1394     if (!Res.isInvalid())
1395       Res = Actions.ActOnCoawaitExpr(getCurScope(), CoawaitLoc, Res.get());
1396     return Res;
1397   }
1398 
1399   case tok::kw___extension__:{//unary-expression:'__extension__' cast-expr [GNU]
1400     // __extension__ silences extension warnings in the subexpression.
1401     if (NotPrimaryExpression)
1402       *NotPrimaryExpression = true;
1403     ExtensionRAIIObject O(Diags);  // Use RAII to do this.
1404     SourceLocation SavedLoc = ConsumeToken();
1405     Res = ParseCastExpression(AnyCastExpr);
1406     if (!Res.isInvalid())
1407       Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Res.get());
1408     return Res;
1409   }
1410   case tok::kw__Alignof:   // unary-expression: '_Alignof' '(' type-name ')'
1411     if (!getLangOpts().C11)
1412       Diag(Tok, diag::ext_c11_feature) << Tok.getName();
1413     LLVM_FALLTHROUGH;
1414   case tok::kw_alignof:    // unary-expression: 'alignof' '(' type-id ')'
1415   case tok::kw___alignof:  // unary-expression: '__alignof' unary-expression
1416                            // unary-expression: '__alignof' '(' type-name ')'
1417   case tok::kw_sizeof:     // unary-expression: 'sizeof' unary-expression
1418                            // unary-expression: 'sizeof' '(' type-name ')'
1419   case tok::kw_vec_step:   // unary-expression: OpenCL 'vec_step' expression
1420   // unary-expression: '__builtin_omp_required_simd_align' '(' type-name ')'
1421   case tok::kw___builtin_omp_required_simd_align:
1422     if (NotPrimaryExpression)
1423       *NotPrimaryExpression = true;
1424     AllowSuffix = false;
1425     Res = ParseUnaryExprOrTypeTraitExpression();
1426     break;
1427   case tok::ampamp: {      // unary-expression: '&&' identifier
1428     if (NotPrimaryExpression)
1429       *NotPrimaryExpression = true;
1430     SourceLocation AmpAmpLoc = ConsumeToken();
1431     if (Tok.isNot(tok::identifier))
1432       return ExprError(Diag(Tok, diag::err_expected) << tok::identifier);
1433 
1434     if (getCurScope()->getFnParent() == nullptr)
1435       return ExprError(Diag(Tok, diag::err_address_of_label_outside_fn));
1436 
1437     Diag(AmpAmpLoc, diag::ext_gnu_address_of_label);
1438     LabelDecl *LD = Actions.LookupOrCreateLabel(Tok.getIdentifierInfo(),
1439                                                 Tok.getLocation());
1440     Res = Actions.ActOnAddrLabel(AmpAmpLoc, Tok.getLocation(), LD);
1441     ConsumeToken();
1442     AllowSuffix = false;
1443     break;
1444   }
1445   case tok::kw_const_cast:
1446   case tok::kw_dynamic_cast:
1447   case tok::kw_reinterpret_cast:
1448   case tok::kw_static_cast:
1449   case tok::kw_addrspace_cast:
1450     if (NotPrimaryExpression)
1451       *NotPrimaryExpression = true;
1452     Res = ParseCXXCasts();
1453     break;
1454   case tok::kw___builtin_bit_cast:
1455     if (NotPrimaryExpression)
1456       *NotPrimaryExpression = true;
1457     Res = ParseBuiltinBitCast();
1458     break;
1459   case tok::kw_typeid:
1460     if (NotPrimaryExpression)
1461       *NotPrimaryExpression = true;
1462     Res = ParseCXXTypeid();
1463     break;
1464   case tok::kw___uuidof:
1465     if (NotPrimaryExpression)
1466       *NotPrimaryExpression = true;
1467     Res = ParseCXXUuidof();
1468     break;
1469   case tok::kw_this:
1470     Res = ParseCXXThis();
1471     break;
1472 
1473   case tok::annot_typename:
1474     if (isStartOfObjCClassMessageMissingOpenBracket()) {
1475       TypeResult Type = getTypeAnnotation(Tok);
1476 
1477       // Fake up a Declarator to use with ActOnTypeName.
1478       DeclSpec DS(AttrFactory);
1479       DS.SetRangeStart(Tok.getLocation());
1480       DS.SetRangeEnd(Tok.getLastLoc());
1481 
1482       const char *PrevSpec = nullptr;
1483       unsigned DiagID;
1484       DS.SetTypeSpecType(TST_typename, Tok.getAnnotationEndLoc(),
1485                          PrevSpec, DiagID, Type,
1486                          Actions.getASTContext().getPrintingPolicy());
1487 
1488       Declarator DeclaratorInfo(DS, DeclaratorContext::TypeName);
1489       TypeResult Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
1490       if (Ty.isInvalid())
1491         break;
1492 
1493       ConsumeAnnotationToken();
1494       Res = ParseObjCMessageExpressionBody(SourceLocation(), SourceLocation(),
1495                                            Ty.get(), nullptr);
1496       break;
1497     }
1498     LLVM_FALLTHROUGH;
1499 
1500   case tok::annot_decltype:
1501   case tok::kw_char:
1502   case tok::kw_wchar_t:
1503   case tok::kw_char8_t:
1504   case tok::kw_char16_t:
1505   case tok::kw_char32_t:
1506   case tok::kw_bool:
1507   case tok::kw_short:
1508   case tok::kw_int:
1509   case tok::kw_long:
1510   case tok::kw___int64:
1511   case tok::kw___int128:
1512   case tok::kw__ExtInt:
1513   case tok::kw_signed:
1514   case tok::kw_unsigned:
1515   case tok::kw_half:
1516   case tok::kw_float:
1517   case tok::kw_double:
1518   case tok::kw___bf16:
1519   case tok::kw__Float16:
1520   case tok::kw___float128:
1521   case tok::kw_void:
1522   case tok::kw_typename:
1523   case tok::kw_typeof:
1524   case tok::kw___vector:
1525 #define GENERIC_IMAGE_TYPE(ImgType, Id) case tok::kw_##ImgType##_t:
1526 #include "clang/Basic/OpenCLImageTypes.def"
1527   {
1528     if (!getLangOpts().CPlusPlus) {
1529       Diag(Tok, diag::err_expected_expression);
1530       return ExprError();
1531     }
1532 
1533     // Everything henceforth is a postfix-expression.
1534     if (NotPrimaryExpression)
1535       *NotPrimaryExpression = true;
1536 
1537     if (SavedKind == tok::kw_typename) {
1538       // postfix-expression: typename-specifier '(' expression-list[opt] ')'
1539       //                     typename-specifier braced-init-list
1540       if (TryAnnotateTypeOrScopeToken())
1541         return ExprError();
1542 
1543       if (!Actions.isSimpleTypeSpecifier(Tok.getKind()))
1544         // We are trying to parse a simple-type-specifier but might not get such
1545         // a token after error recovery.
1546         return ExprError();
1547     }
1548 
1549     // postfix-expression: simple-type-specifier '(' expression-list[opt] ')'
1550     //                     simple-type-specifier braced-init-list
1551     //
1552     DeclSpec DS(AttrFactory);
1553 
1554     ParseCXXSimpleTypeSpecifier(DS);
1555     if (Tok.isNot(tok::l_paren) &&
1556         (!getLangOpts().CPlusPlus11 || Tok.isNot(tok::l_brace)))
1557       return ExprError(Diag(Tok, diag::err_expected_lparen_after_type)
1558                          << DS.getSourceRange());
1559 
1560     if (Tok.is(tok::l_brace))
1561       Diag(Tok, diag::warn_cxx98_compat_generalized_initializer_lists);
1562 
1563     Res = ParseCXXTypeConstructExpression(DS);
1564     break;
1565   }
1566 
1567   case tok::annot_cxxscope: { // [C++] id-expression: qualified-id
1568     // If TryAnnotateTypeOrScopeToken annotates the token, tail recurse.
1569     // (We can end up in this situation after tentative parsing.)
1570     if (TryAnnotateTypeOrScopeToken())
1571       return ExprError();
1572     if (!Tok.is(tok::annot_cxxscope))
1573       return ParseCastExpression(ParseKind, isAddressOfOperand, NotCastExpr,
1574                                  isTypeCast, isVectorLiteral,
1575                                  NotPrimaryExpression);
1576 
1577     Token Next = NextToken();
1578     if (Next.is(tok::annot_template_id)) {
1579       TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Next);
1580       if (TemplateId->Kind == TNK_Type_template) {
1581         // We have a qualified template-id that we know refers to a
1582         // type, translate it into a type and continue parsing as a
1583         // cast expression.
1584         CXXScopeSpec SS;
1585         ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/nullptr,
1586                                        /*ObjectHadErrors=*/false,
1587                                        /*EnteringContext=*/false);
1588         AnnotateTemplateIdTokenAsType(SS);
1589         return ParseCastExpression(ParseKind, isAddressOfOperand, NotCastExpr,
1590                                    isTypeCast, isVectorLiteral,
1591                                    NotPrimaryExpression);
1592       }
1593     }
1594 
1595     // Parse as an id-expression.
1596     Res = ParseCXXIdExpression(isAddressOfOperand);
1597     break;
1598   }
1599 
1600   case tok::annot_template_id: { // [C++]          template-id
1601     TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
1602     if (TemplateId->Kind == TNK_Type_template) {
1603       // We have a template-id that we know refers to a type,
1604       // translate it into a type and continue parsing as a cast
1605       // expression.
1606       CXXScopeSpec SS;
1607       AnnotateTemplateIdTokenAsType(SS);
1608       return ParseCastExpression(ParseKind, isAddressOfOperand,
1609                                  NotCastExpr, isTypeCast, isVectorLiteral,
1610                                  NotPrimaryExpression);
1611     }
1612 
1613     // Fall through to treat the template-id as an id-expression.
1614     LLVM_FALLTHROUGH;
1615   }
1616 
1617   case tok::kw_operator: // [C++] id-expression: operator/conversion-function-id
1618     Res = ParseCXXIdExpression(isAddressOfOperand);
1619     break;
1620 
1621   case tok::coloncolon: {
1622     // ::foo::bar -> global qualified name etc.   If TryAnnotateTypeOrScopeToken
1623     // annotates the token, tail recurse.
1624     if (TryAnnotateTypeOrScopeToken())
1625       return ExprError();
1626     if (!Tok.is(tok::coloncolon))
1627       return ParseCastExpression(ParseKind, isAddressOfOperand, isTypeCast,
1628                                  isVectorLiteral, NotPrimaryExpression);
1629 
1630     // ::new -> [C++] new-expression
1631     // ::delete -> [C++] delete-expression
1632     SourceLocation CCLoc = ConsumeToken();
1633     if (Tok.is(tok::kw_new)) {
1634       if (NotPrimaryExpression)
1635         *NotPrimaryExpression = true;
1636       Res = ParseCXXNewExpression(true, CCLoc);
1637       AllowSuffix = false;
1638       break;
1639     }
1640     if (Tok.is(tok::kw_delete)) {
1641       if (NotPrimaryExpression)
1642         *NotPrimaryExpression = true;
1643       Res = ParseCXXDeleteExpression(true, CCLoc);
1644       AllowSuffix = false;
1645       break;
1646     }
1647 
1648     // This is not a type name or scope specifier, it is an invalid expression.
1649     Diag(CCLoc, diag::err_expected_expression);
1650     return ExprError();
1651   }
1652 
1653   case tok::kw_new: // [C++] new-expression
1654     if (NotPrimaryExpression)
1655       *NotPrimaryExpression = true;
1656     Res = ParseCXXNewExpression(false, Tok.getLocation());
1657     AllowSuffix = false;
1658     break;
1659 
1660   case tok::kw_delete: // [C++] delete-expression
1661     if (NotPrimaryExpression)
1662       *NotPrimaryExpression = true;
1663     Res = ParseCXXDeleteExpression(false, Tok.getLocation());
1664     AllowSuffix = false;
1665     break;
1666 
1667   case tok::kw_requires: // [C++2a] requires-expression
1668     Res = ParseRequiresExpression();
1669     AllowSuffix = false;
1670     break;
1671 
1672   case tok::kw_noexcept: { // [C++0x] 'noexcept' '(' expression ')'
1673     if (NotPrimaryExpression)
1674       *NotPrimaryExpression = true;
1675     Diag(Tok, diag::warn_cxx98_compat_noexcept_expr);
1676     SourceLocation KeyLoc = ConsumeToken();
1677     BalancedDelimiterTracker T(*this, tok::l_paren);
1678 
1679     if (T.expectAndConsume(diag::err_expected_lparen_after, "noexcept"))
1680       return ExprError();
1681     // C++11 [expr.unary.noexcept]p1:
1682     //   The noexcept operator determines whether the evaluation of its operand,
1683     //   which is an unevaluated operand, can throw an exception.
1684     EnterExpressionEvaluationContext Unevaluated(
1685         Actions, Sema::ExpressionEvaluationContext::Unevaluated);
1686     Res = ParseExpression();
1687 
1688     T.consumeClose();
1689 
1690     if (!Res.isInvalid())
1691       Res = Actions.ActOnNoexceptExpr(KeyLoc, T.getOpenLocation(), Res.get(),
1692                                       T.getCloseLocation());
1693     AllowSuffix = false;
1694     break;
1695   }
1696 
1697 #define TYPE_TRAIT(N,Spelling,K) \
1698   case tok::kw_##Spelling:
1699 #include "clang/Basic/TokenKinds.def"
1700     Res = ParseTypeTrait();
1701     break;
1702 
1703   case tok::kw___array_rank:
1704   case tok::kw___array_extent:
1705     if (NotPrimaryExpression)
1706       *NotPrimaryExpression = true;
1707     Res = ParseArrayTypeTrait();
1708     break;
1709 
1710   case tok::kw___is_lvalue_expr:
1711   case tok::kw___is_rvalue_expr:
1712     if (NotPrimaryExpression)
1713       *NotPrimaryExpression = true;
1714     Res = ParseExpressionTrait();
1715     break;
1716 
1717   case tok::at: {
1718     if (NotPrimaryExpression)
1719       *NotPrimaryExpression = true;
1720     SourceLocation AtLoc = ConsumeToken();
1721     return ParseObjCAtExpression(AtLoc);
1722   }
1723   case tok::caret:
1724     Res = ParseBlockLiteralExpression();
1725     break;
1726   case tok::code_completion: {
1727     cutOffParsing();
1728     Actions.CodeCompleteExpression(getCurScope(),
1729                                    PreferredType.get(Tok.getLocation()));
1730     return ExprError();
1731   }
1732   case tok::l_square:
1733     if (getLangOpts().CPlusPlus11) {
1734       if (getLangOpts().ObjC) {
1735         // C++11 lambda expressions and Objective-C message sends both start with a
1736         // square bracket.  There are three possibilities here:
1737         // we have a valid lambda expression, we have an invalid lambda
1738         // expression, or we have something that doesn't appear to be a lambda.
1739         // If we're in the last case, we fall back to ParseObjCMessageExpression.
1740         Res = TryParseLambdaExpression();
1741         if (!Res.isInvalid() && !Res.get()) {
1742           // We assume Objective-C++ message expressions are not
1743           // primary-expressions.
1744           if (NotPrimaryExpression)
1745             *NotPrimaryExpression = true;
1746           Res = ParseObjCMessageExpression();
1747         }
1748         break;
1749       }
1750       Res = ParseLambdaExpression();
1751       break;
1752     }
1753     if (getLangOpts().ObjC) {
1754       Res = ParseObjCMessageExpression();
1755       break;
1756     }
1757     LLVM_FALLTHROUGH;
1758   default:
1759     NotCastExpr = true;
1760     return ExprError();
1761   }
1762 
1763   // Check to see whether Res is a function designator only. If it is and we
1764   // are compiling for OpenCL, we need to return an error as this implies
1765   // that the address of the function is being taken, which is illegal in CL.
1766 
1767   if (ParseKind == PrimaryExprOnly)
1768     // This is strictly a primary-expression - no postfix-expr pieces should be
1769     // parsed.
1770     return Res;
1771 
1772   if (!AllowSuffix) {
1773     // FIXME: Don't parse a primary-expression suffix if we encountered a parse
1774     // error already.
1775     if (Res.isInvalid())
1776       return Res;
1777 
1778     switch (Tok.getKind()) {
1779     case tok::l_square:
1780     case tok::l_paren:
1781     case tok::plusplus:
1782     case tok::minusminus:
1783       // "expected ';'" or similar is probably the right diagnostic here. Let
1784       // the caller decide what to do.
1785       if (Tok.isAtStartOfLine())
1786         return Res;
1787 
1788       LLVM_FALLTHROUGH;
1789     case tok::period:
1790     case tok::arrow:
1791       break;
1792 
1793     default:
1794       return Res;
1795     }
1796 
1797     // This was a unary-expression for which a postfix-expression suffix is
1798     // not permitted by the grammar (eg, a sizeof expression or
1799     // new-expression or similar). Diagnose but parse the suffix anyway.
1800     Diag(Tok.getLocation(), diag::err_postfix_after_unary_requires_parens)
1801         << Tok.getKind() << Res.get()->getSourceRange()
1802         << FixItHint::CreateInsertion(Res.get()->getBeginLoc(), "(")
1803         << FixItHint::CreateInsertion(PP.getLocForEndOfToken(PrevTokLocation),
1804                                       ")");
1805   }
1806 
1807   // These can be followed by postfix-expr pieces.
1808   PreferredType = SavedType;
1809   Res = ParsePostfixExpressionSuffix(Res);
1810   if (getLangOpts().OpenCL &&
1811       !getActions().getOpenCLOptions().isAvailableOption(
1812           "__cl_clang_function_pointers", getLangOpts()))
1813     if (Expr *PostfixExpr = Res.get()) {
1814       QualType Ty = PostfixExpr->getType();
1815       if (!Ty.isNull() && Ty->isFunctionType()) {
1816         Diag(PostfixExpr->getExprLoc(),
1817              diag::err_opencl_taking_function_address_parser);
1818         return ExprError();
1819       }
1820     }
1821 
1822   return Res;
1823 }
1824 
1825 /// Once the leading part of a postfix-expression is parsed, this
1826 /// method parses any suffixes that apply.
1827 ///
1828 /// \verbatim
1829 ///       postfix-expression: [C99 6.5.2]
1830 ///         primary-expression
1831 ///         postfix-expression '[' expression ']'
1832 ///         postfix-expression '[' braced-init-list ']'
1833 ///         postfix-expression '(' argument-expression-list[opt] ')'
1834 ///         postfix-expression '.' identifier
1835 ///         postfix-expression '->' identifier
1836 ///         postfix-expression '++'
1837 ///         postfix-expression '--'
1838 ///         '(' type-name ')' '{' initializer-list '}'
1839 ///         '(' type-name ')' '{' initializer-list ',' '}'
1840 ///
1841 ///       argument-expression-list: [C99 6.5.2]
1842 ///         argument-expression ...[opt]
1843 ///         argument-expression-list ',' assignment-expression ...[opt]
1844 /// \endverbatim
1845 ExprResult
ParsePostfixExpressionSuffix(ExprResult LHS)1846 Parser::ParsePostfixExpressionSuffix(ExprResult LHS) {
1847   // Now that the primary-expression piece of the postfix-expression has been
1848   // parsed, see if there are any postfix-expression pieces here.
1849   SourceLocation Loc;
1850   auto SavedType = PreferredType;
1851   while (1) {
1852     // Each iteration relies on preferred type for the whole expression.
1853     PreferredType = SavedType;
1854     switch (Tok.getKind()) {
1855     case tok::code_completion:
1856       if (InMessageExpression)
1857         return LHS;
1858 
1859       cutOffParsing();
1860       Actions.CodeCompletePostfixExpression(
1861           getCurScope(), LHS, PreferredType.get(Tok.getLocation()));
1862       return ExprError();
1863 
1864     case tok::identifier:
1865       // If we see identifier: after an expression, and we're not already in a
1866       // message send, then this is probably a message send with a missing
1867       // opening bracket '['.
1868       if (getLangOpts().ObjC && !InMessageExpression &&
1869           (NextToken().is(tok::colon) || NextToken().is(tok::r_square))) {
1870         LHS = ParseObjCMessageExpressionBody(SourceLocation(), SourceLocation(),
1871                                              nullptr, LHS.get());
1872         break;
1873       }
1874       // Fall through; this isn't a message send.
1875       LLVM_FALLTHROUGH;
1876 
1877     default:  // Not a postfix-expression suffix.
1878       return LHS;
1879     case tok::l_square: {  // postfix-expression: p-e '[' expression ']'
1880       // If we have a array postfix expression that starts on a new line and
1881       // Objective-C is enabled, it is highly likely that the user forgot a
1882       // semicolon after the base expression and that the array postfix-expr is
1883       // actually another message send.  In this case, do some look-ahead to see
1884       // if the contents of the square brackets are obviously not a valid
1885       // expression and recover by pretending there is no suffix.
1886       if (getLangOpts().ObjC && Tok.isAtStartOfLine() &&
1887           isSimpleObjCMessageExpression())
1888         return LHS;
1889 
1890       // Reject array indices starting with a lambda-expression. '[[' is
1891       // reserved for attributes.
1892       if (CheckProhibitedCXX11Attribute()) {
1893         (void)Actions.CorrectDelayedTyposInExpr(LHS);
1894         return ExprError();
1895       }
1896 
1897       BalancedDelimiterTracker T(*this, tok::l_square);
1898       T.consumeOpen();
1899       Loc = T.getOpenLocation();
1900       ExprResult Idx, Length, Stride;
1901       SourceLocation ColonLocFirst, ColonLocSecond;
1902       PreferredType.enterSubscript(Actions, Tok.getLocation(), LHS.get());
1903       if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
1904         Diag(Tok, diag::warn_cxx98_compat_generalized_initializer_lists);
1905         Idx = ParseBraceInitializer();
1906       } else if (getLangOpts().OpenMP) {
1907         ColonProtectionRAIIObject RAII(*this);
1908         // Parse [: or [ expr or [ expr :
1909         if (!Tok.is(tok::colon)) {
1910           // [ expr
1911           Idx = ParseExpression();
1912         }
1913         if (Tok.is(tok::colon)) {
1914           // Consume ':'
1915           ColonLocFirst = ConsumeToken();
1916           if (Tok.isNot(tok::r_square) &&
1917               (getLangOpts().OpenMP < 50 ||
1918                ((Tok.isNot(tok::colon) && getLangOpts().OpenMP >= 50))))
1919             Length = ParseExpression();
1920         }
1921         if (getLangOpts().OpenMP >= 50 &&
1922             (OMPClauseKind == llvm::omp::Clause::OMPC_to ||
1923              OMPClauseKind == llvm::omp::Clause::OMPC_from) &&
1924             Tok.is(tok::colon)) {
1925           // Consume ':'
1926           ColonLocSecond = ConsumeToken();
1927           if (Tok.isNot(tok::r_square)) {
1928             Stride = ParseExpression();
1929           }
1930         }
1931       } else
1932         Idx = ParseExpression();
1933 
1934       SourceLocation RLoc = Tok.getLocation();
1935 
1936       LHS = Actions.CorrectDelayedTyposInExpr(LHS);
1937       Idx = Actions.CorrectDelayedTyposInExpr(Idx);
1938       Length = Actions.CorrectDelayedTyposInExpr(Length);
1939       if (!LHS.isInvalid() && !Idx.isInvalid() && !Length.isInvalid() &&
1940           !Stride.isInvalid() && Tok.is(tok::r_square)) {
1941         if (ColonLocFirst.isValid() || ColonLocSecond.isValid()) {
1942           LHS = Actions.ActOnOMPArraySectionExpr(
1943               LHS.get(), Loc, Idx.get(), ColonLocFirst, ColonLocSecond,
1944               Length.get(), Stride.get(), RLoc);
1945         } else {
1946           LHS = Actions.ActOnArraySubscriptExpr(getCurScope(), LHS.get(), Loc,
1947                                                 Idx.get(), RLoc);
1948         }
1949       } else {
1950         LHS = ExprError();
1951         Idx = ExprError();
1952       }
1953 
1954       // Match the ']'.
1955       T.consumeClose();
1956       break;
1957     }
1958 
1959     case tok::l_paren:         // p-e: p-e '(' argument-expression-list[opt] ')'
1960     case tok::lesslessless: {  // p-e: p-e '<<<' argument-expression-list '>>>'
1961                                //   '(' argument-expression-list[opt] ')'
1962       tok::TokenKind OpKind = Tok.getKind();
1963       InMessageExpressionRAIIObject InMessage(*this, false);
1964 
1965       Expr *ExecConfig = nullptr;
1966 
1967       BalancedDelimiterTracker PT(*this, tok::l_paren);
1968 
1969       if (OpKind == tok::lesslessless) {
1970         ExprVector ExecConfigExprs;
1971         CommaLocsTy ExecConfigCommaLocs;
1972         SourceLocation OpenLoc = ConsumeToken();
1973 
1974         if (ParseSimpleExpressionList(ExecConfigExprs, ExecConfigCommaLocs)) {
1975           (void)Actions.CorrectDelayedTyposInExpr(LHS);
1976           LHS = ExprError();
1977         }
1978 
1979         SourceLocation CloseLoc;
1980         if (TryConsumeToken(tok::greatergreatergreater, CloseLoc)) {
1981         } else if (LHS.isInvalid()) {
1982           SkipUntil(tok::greatergreatergreater, StopAtSemi);
1983         } else {
1984           // There was an error closing the brackets
1985           Diag(Tok, diag::err_expected) << tok::greatergreatergreater;
1986           Diag(OpenLoc, diag::note_matching) << tok::lesslessless;
1987           SkipUntil(tok::greatergreatergreater, StopAtSemi);
1988           LHS = ExprError();
1989         }
1990 
1991         if (!LHS.isInvalid()) {
1992           if (ExpectAndConsume(tok::l_paren))
1993             LHS = ExprError();
1994           else
1995             Loc = PrevTokLocation;
1996         }
1997 
1998         if (!LHS.isInvalid()) {
1999           ExprResult ECResult = Actions.ActOnCUDAExecConfigExpr(getCurScope(),
2000                                     OpenLoc,
2001                                     ExecConfigExprs,
2002                                     CloseLoc);
2003           if (ECResult.isInvalid())
2004             LHS = ExprError();
2005           else
2006             ExecConfig = ECResult.get();
2007         }
2008       } else {
2009         PT.consumeOpen();
2010         Loc = PT.getOpenLocation();
2011       }
2012 
2013       ExprVector ArgExprs;
2014       CommaLocsTy CommaLocs;
2015       auto RunSignatureHelp = [&]() -> QualType {
2016         QualType PreferredType = Actions.ProduceCallSignatureHelp(
2017             getCurScope(), LHS.get(), ArgExprs, PT.getOpenLocation());
2018         CalledSignatureHelp = true;
2019         return PreferredType;
2020       };
2021       if (OpKind == tok::l_paren || !LHS.isInvalid()) {
2022         if (Tok.isNot(tok::r_paren)) {
2023           if (ParseExpressionList(ArgExprs, CommaLocs, [&] {
2024                 PreferredType.enterFunctionArgument(Tok.getLocation(),
2025                                                     RunSignatureHelp);
2026               })) {
2027             (void)Actions.CorrectDelayedTyposInExpr(LHS);
2028             // If we got an error when parsing expression list, we don't call
2029             // the CodeCompleteCall handler inside the parser. So call it here
2030             // to make sure we get overload suggestions even when we are in the
2031             // middle of a parameter.
2032             if (PP.isCodeCompletionReached() && !CalledSignatureHelp)
2033               RunSignatureHelp();
2034             LHS = ExprError();
2035           } else if (LHS.isInvalid()) {
2036             for (auto &E : ArgExprs)
2037               Actions.CorrectDelayedTyposInExpr(E);
2038           }
2039         }
2040       }
2041 
2042       // Match the ')'.
2043       if (LHS.isInvalid()) {
2044         SkipUntil(tok::r_paren, StopAtSemi);
2045       } else if (Tok.isNot(tok::r_paren)) {
2046         bool HadDelayedTypo = false;
2047         if (Actions.CorrectDelayedTyposInExpr(LHS).get() != LHS.get())
2048           HadDelayedTypo = true;
2049         for (auto &E : ArgExprs)
2050           if (Actions.CorrectDelayedTyposInExpr(E).get() != E)
2051             HadDelayedTypo = true;
2052         // If there were delayed typos in the LHS or ArgExprs, call SkipUntil
2053         // instead of PT.consumeClose() to avoid emitting extra diagnostics for
2054         // the unmatched l_paren.
2055         if (HadDelayedTypo)
2056           SkipUntil(tok::r_paren, StopAtSemi);
2057         else
2058           PT.consumeClose();
2059         LHS = ExprError();
2060       } else {
2061         assert(
2062             (ArgExprs.size() == 0 || ArgExprs.size() - 1 == CommaLocs.size()) &&
2063             "Unexpected number of commas!");
2064         Expr *Fn = LHS.get();
2065         SourceLocation RParLoc = Tok.getLocation();
2066         LHS = Actions.ActOnCallExpr(getCurScope(), Fn, Loc, ArgExprs, RParLoc,
2067                                     ExecConfig);
2068         if (LHS.isInvalid()) {
2069           ArgExprs.insert(ArgExprs.begin(), Fn);
2070           LHS =
2071               Actions.CreateRecoveryExpr(Fn->getBeginLoc(), RParLoc, ArgExprs);
2072         }
2073         PT.consumeClose();
2074       }
2075 
2076       break;
2077     }
2078     case tok::arrow:
2079     case tok::period: {
2080       // postfix-expression: p-e '->' template[opt] id-expression
2081       // postfix-expression: p-e '.' template[opt] id-expression
2082       tok::TokenKind OpKind = Tok.getKind();
2083       SourceLocation OpLoc = ConsumeToken();  // Eat the "." or "->" token.
2084 
2085       CXXScopeSpec SS;
2086       ParsedType ObjectType;
2087       bool MayBePseudoDestructor = false;
2088       Expr* OrigLHS = !LHS.isInvalid() ? LHS.get() : nullptr;
2089 
2090       PreferredType.enterMemAccess(Actions, Tok.getLocation(), OrigLHS);
2091 
2092       if (getLangOpts().CPlusPlus && !LHS.isInvalid()) {
2093         Expr *Base = OrigLHS;
2094         const Type* BaseType = Base->getType().getTypePtrOrNull();
2095         if (BaseType && Tok.is(tok::l_paren) &&
2096             (BaseType->isFunctionType() ||
2097              BaseType->isSpecificPlaceholderType(BuiltinType::BoundMember))) {
2098           Diag(OpLoc, diag::err_function_is_not_record)
2099               << OpKind << Base->getSourceRange()
2100               << FixItHint::CreateRemoval(OpLoc);
2101           return ParsePostfixExpressionSuffix(Base);
2102         }
2103 
2104         LHS = Actions.ActOnStartCXXMemberReference(getCurScope(), Base, OpLoc,
2105                                                    OpKind, ObjectType,
2106                                                    MayBePseudoDestructor);
2107         if (LHS.isInvalid()) {
2108           // Clang will try to perform expression based completion as a
2109           // fallback, which is confusing in case of member references. So we
2110           // stop here without any completions.
2111           if (Tok.is(tok::code_completion)) {
2112             cutOffParsing();
2113             return ExprError();
2114           }
2115           break;
2116         }
2117         ParseOptionalCXXScopeSpecifier(
2118             SS, ObjectType, LHS.get() && LHS.get()->containsErrors(),
2119             /*EnteringContext=*/false, &MayBePseudoDestructor);
2120         if (SS.isNotEmpty())
2121           ObjectType = nullptr;
2122       }
2123 
2124       if (Tok.is(tok::code_completion)) {
2125         tok::TokenKind CorrectedOpKind =
2126             OpKind == tok::arrow ? tok::period : tok::arrow;
2127         ExprResult CorrectedLHS(/*Invalid=*/true);
2128         if (getLangOpts().CPlusPlus && OrigLHS) {
2129           // FIXME: Creating a TentativeAnalysisScope from outside Sema is a
2130           // hack.
2131           Sema::TentativeAnalysisScope Trap(Actions);
2132           CorrectedLHS = Actions.ActOnStartCXXMemberReference(
2133               getCurScope(), OrigLHS, OpLoc, CorrectedOpKind, ObjectType,
2134               MayBePseudoDestructor);
2135         }
2136 
2137         Expr *Base = LHS.get();
2138         Expr *CorrectedBase = CorrectedLHS.get();
2139         if (!CorrectedBase && !getLangOpts().CPlusPlus)
2140           CorrectedBase = Base;
2141 
2142         // Code completion for a member access expression.
2143         cutOffParsing();
2144         Actions.CodeCompleteMemberReferenceExpr(
2145             getCurScope(), Base, CorrectedBase, OpLoc, OpKind == tok::arrow,
2146             Base && ExprStatementTokLoc == Base->getBeginLoc(),
2147             PreferredType.get(Tok.getLocation()));
2148 
2149         return ExprError();
2150       }
2151 
2152       if (MayBePseudoDestructor && !LHS.isInvalid()) {
2153         LHS = ParseCXXPseudoDestructor(LHS.get(), OpLoc, OpKind, SS,
2154                                        ObjectType);
2155         break;
2156       }
2157 
2158       // Either the action has told us that this cannot be a
2159       // pseudo-destructor expression (based on the type of base
2160       // expression), or we didn't see a '~' in the right place. We
2161       // can still parse a destructor name here, but in that case it
2162       // names a real destructor.
2163       // Allow explicit constructor calls in Microsoft mode.
2164       // FIXME: Add support for explicit call of template constructor.
2165       SourceLocation TemplateKWLoc;
2166       UnqualifiedId Name;
2167       if (getLangOpts().ObjC && OpKind == tok::period &&
2168           Tok.is(tok::kw_class)) {
2169         // Objective-C++:
2170         //   After a '.' in a member access expression, treat the keyword
2171         //   'class' as if it were an identifier.
2172         //
2173         // This hack allows property access to the 'class' method because it is
2174         // such a common method name. For other C++ keywords that are
2175         // Objective-C method names, one must use the message send syntax.
2176         IdentifierInfo *Id = Tok.getIdentifierInfo();
2177         SourceLocation Loc = ConsumeToken();
2178         Name.setIdentifier(Id, Loc);
2179       } else if (ParseUnqualifiedId(
2180                      SS, ObjectType, LHS.get() && LHS.get()->containsErrors(),
2181                      /*EnteringContext=*/false,
2182                      /*AllowDestructorName=*/true,
2183                      /*AllowConstructorName=*/
2184                      getLangOpts().MicrosoftExt && SS.isNotEmpty(),
2185                      /*AllowDeductionGuide=*/false, &TemplateKWLoc, Name)) {
2186         (void)Actions.CorrectDelayedTyposInExpr(LHS);
2187         LHS = ExprError();
2188       }
2189 
2190       if (!LHS.isInvalid())
2191         LHS = Actions.ActOnMemberAccessExpr(getCurScope(), LHS.get(), OpLoc,
2192                                             OpKind, SS, TemplateKWLoc, Name,
2193                                  CurParsedObjCImpl ? CurParsedObjCImpl->Dcl
2194                                                    : nullptr);
2195       if (!LHS.isInvalid()) {
2196         if (Tok.is(tok::less))
2197           checkPotentialAngleBracket(LHS);
2198       } else if (OrigLHS && Name.isValid()) {
2199         // Preserve the LHS if the RHS is an invalid member.
2200         LHS = Actions.CreateRecoveryExpr(OrigLHS->getBeginLoc(),
2201                                          Name.getEndLoc(), {OrigLHS});
2202       }
2203       break;
2204     }
2205     case tok::plusplus:    // postfix-expression: postfix-expression '++'
2206     case tok::minusminus:  // postfix-expression: postfix-expression '--'
2207       if (!LHS.isInvalid()) {
2208         Expr *Arg = LHS.get();
2209         LHS = Actions.ActOnPostfixUnaryOp(getCurScope(), Tok.getLocation(),
2210                                           Tok.getKind(), Arg);
2211         if (LHS.isInvalid())
2212           LHS = Actions.CreateRecoveryExpr(Arg->getBeginLoc(),
2213                                            Tok.getLocation(), Arg);
2214       }
2215       ConsumeToken();
2216       break;
2217     }
2218   }
2219 }
2220 
2221 /// ParseExprAfterUnaryExprOrTypeTrait - We parsed a typeof/sizeof/alignof/
2222 /// vec_step and we are at the start of an expression or a parenthesized
2223 /// type-id. OpTok is the operand token (typeof/sizeof/alignof). Returns the
2224 /// expression (isCastExpr == false) or the type (isCastExpr == true).
2225 ///
2226 /// \verbatim
2227 ///       unary-expression:  [C99 6.5.3]
2228 ///         'sizeof' unary-expression
2229 ///         'sizeof' '(' type-name ')'
2230 /// [GNU]   '__alignof' unary-expression
2231 /// [GNU]   '__alignof' '(' type-name ')'
2232 /// [C11]   '_Alignof' '(' type-name ')'
2233 /// [C++0x] 'alignof' '(' type-id ')'
2234 ///
2235 /// [GNU]   typeof-specifier:
2236 ///           typeof ( expressions )
2237 ///           typeof ( type-name )
2238 /// [GNU/C++] typeof unary-expression
2239 ///
2240 /// [OpenCL 1.1 6.11.12] vec_step built-in function:
2241 ///           vec_step ( expressions )
2242 ///           vec_step ( type-name )
2243 /// \endverbatim
2244 ExprResult
ParseExprAfterUnaryExprOrTypeTrait(const Token & OpTok,bool & isCastExpr,ParsedType & CastTy,SourceRange & CastRange)2245 Parser::ParseExprAfterUnaryExprOrTypeTrait(const Token &OpTok,
2246                                            bool &isCastExpr,
2247                                            ParsedType &CastTy,
2248                                            SourceRange &CastRange) {
2249 
2250   assert(OpTok.isOneOf(tok::kw_typeof, tok::kw_sizeof, tok::kw___alignof,
2251                        tok::kw_alignof, tok::kw__Alignof, tok::kw_vec_step,
2252                        tok::kw___builtin_omp_required_simd_align) &&
2253          "Not a typeof/sizeof/alignof/vec_step expression!");
2254 
2255   ExprResult Operand;
2256 
2257   // If the operand doesn't start with an '(', it must be an expression.
2258   if (Tok.isNot(tok::l_paren)) {
2259     // If construct allows a form without parenthesis, user may forget to put
2260     // pathenthesis around type name.
2261     if (OpTok.isOneOf(tok::kw_sizeof, tok::kw___alignof, tok::kw_alignof,
2262                       tok::kw__Alignof)) {
2263       if (isTypeIdUnambiguously()) {
2264         DeclSpec DS(AttrFactory);
2265         ParseSpecifierQualifierList(DS);
2266         Declarator DeclaratorInfo(DS, DeclaratorContext::TypeName);
2267         ParseDeclarator(DeclaratorInfo);
2268 
2269         SourceLocation LParenLoc = PP.getLocForEndOfToken(OpTok.getLocation());
2270         SourceLocation RParenLoc = PP.getLocForEndOfToken(PrevTokLocation);
2271         if (LParenLoc.isInvalid() || RParenLoc.isInvalid()) {
2272           Diag(OpTok.getLocation(),
2273                diag::err_expected_parentheses_around_typename)
2274               << OpTok.getName();
2275         } else {
2276           Diag(LParenLoc, diag::err_expected_parentheses_around_typename)
2277               << OpTok.getName() << FixItHint::CreateInsertion(LParenLoc, "(")
2278               << FixItHint::CreateInsertion(RParenLoc, ")");
2279         }
2280         isCastExpr = true;
2281         return ExprEmpty();
2282       }
2283     }
2284 
2285     isCastExpr = false;
2286     if (OpTok.is(tok::kw_typeof) && !getLangOpts().CPlusPlus) {
2287       Diag(Tok, diag::err_expected_after) << OpTok.getIdentifierInfo()
2288                                           << tok::l_paren;
2289       return ExprError();
2290     }
2291 
2292     Operand = ParseCastExpression(UnaryExprOnly);
2293   } else {
2294     // If it starts with a '(', we know that it is either a parenthesized
2295     // type-name, or it is a unary-expression that starts with a compound
2296     // literal, or starts with a primary-expression that is a parenthesized
2297     // expression.
2298     ParenParseOption ExprType = CastExpr;
2299     SourceLocation LParenLoc = Tok.getLocation(), RParenLoc;
2300 
2301     Operand = ParseParenExpression(ExprType, true/*stopIfCastExpr*/,
2302                                    false, CastTy, RParenLoc);
2303     CastRange = SourceRange(LParenLoc, RParenLoc);
2304 
2305     // If ParseParenExpression parsed a '(typename)' sequence only, then this is
2306     // a type.
2307     if (ExprType == CastExpr) {
2308       isCastExpr = true;
2309       return ExprEmpty();
2310     }
2311 
2312     if (getLangOpts().CPlusPlus || OpTok.isNot(tok::kw_typeof)) {
2313       // GNU typeof in C requires the expression to be parenthesized. Not so for
2314       // sizeof/alignof or in C++. Therefore, the parenthesized expression is
2315       // the start of a unary-expression, but doesn't include any postfix
2316       // pieces. Parse these now if present.
2317       if (!Operand.isInvalid())
2318         Operand = ParsePostfixExpressionSuffix(Operand.get());
2319     }
2320   }
2321 
2322   // If we get here, the operand to the typeof/sizeof/alignof was an expression.
2323   isCastExpr = false;
2324   return Operand;
2325 }
2326 
2327 
2328 /// Parse a sizeof or alignof expression.
2329 ///
2330 /// \verbatim
2331 ///       unary-expression:  [C99 6.5.3]
2332 ///         'sizeof' unary-expression
2333 ///         'sizeof' '(' type-name ')'
2334 /// [C++11] 'sizeof' '...' '(' identifier ')'
2335 /// [GNU]   '__alignof' unary-expression
2336 /// [GNU]   '__alignof' '(' type-name ')'
2337 /// [C11]   '_Alignof' '(' type-name ')'
2338 /// [C++11] 'alignof' '(' type-id ')'
2339 /// \endverbatim
ParseUnaryExprOrTypeTraitExpression()2340 ExprResult Parser::ParseUnaryExprOrTypeTraitExpression() {
2341   assert(Tok.isOneOf(tok::kw_sizeof, tok::kw___alignof, tok::kw_alignof,
2342                      tok::kw__Alignof, tok::kw_vec_step,
2343                      tok::kw___builtin_omp_required_simd_align) &&
2344          "Not a sizeof/alignof/vec_step expression!");
2345   Token OpTok = Tok;
2346   ConsumeToken();
2347 
2348   // [C++11] 'sizeof' '...' '(' identifier ')'
2349   if (Tok.is(tok::ellipsis) && OpTok.is(tok::kw_sizeof)) {
2350     SourceLocation EllipsisLoc = ConsumeToken();
2351     SourceLocation LParenLoc, RParenLoc;
2352     IdentifierInfo *Name = nullptr;
2353     SourceLocation NameLoc;
2354     if (Tok.is(tok::l_paren)) {
2355       BalancedDelimiterTracker T(*this, tok::l_paren);
2356       T.consumeOpen();
2357       LParenLoc = T.getOpenLocation();
2358       if (Tok.is(tok::identifier)) {
2359         Name = Tok.getIdentifierInfo();
2360         NameLoc = ConsumeToken();
2361         T.consumeClose();
2362         RParenLoc = T.getCloseLocation();
2363         if (RParenLoc.isInvalid())
2364           RParenLoc = PP.getLocForEndOfToken(NameLoc);
2365       } else {
2366         Diag(Tok, diag::err_expected_parameter_pack);
2367         SkipUntil(tok::r_paren, StopAtSemi);
2368       }
2369     } else if (Tok.is(tok::identifier)) {
2370       Name = Tok.getIdentifierInfo();
2371       NameLoc = ConsumeToken();
2372       LParenLoc = PP.getLocForEndOfToken(EllipsisLoc);
2373       RParenLoc = PP.getLocForEndOfToken(NameLoc);
2374       Diag(LParenLoc, diag::err_paren_sizeof_parameter_pack)
2375         << Name
2376         << FixItHint::CreateInsertion(LParenLoc, "(")
2377         << FixItHint::CreateInsertion(RParenLoc, ")");
2378     } else {
2379       Diag(Tok, diag::err_sizeof_parameter_pack);
2380     }
2381 
2382     if (!Name)
2383       return ExprError();
2384 
2385     EnterExpressionEvaluationContext Unevaluated(
2386         Actions, Sema::ExpressionEvaluationContext::Unevaluated,
2387         Sema::ReuseLambdaContextDecl);
2388 
2389     return Actions.ActOnSizeofParameterPackExpr(getCurScope(),
2390                                                 OpTok.getLocation(),
2391                                                 *Name, NameLoc,
2392                                                 RParenLoc);
2393   }
2394 
2395   if (OpTok.isOneOf(tok::kw_alignof, tok::kw__Alignof))
2396     Diag(OpTok, diag::warn_cxx98_compat_alignof);
2397 
2398   EnterExpressionEvaluationContext Unevaluated(
2399       Actions, Sema::ExpressionEvaluationContext::Unevaluated,
2400       Sema::ReuseLambdaContextDecl);
2401 
2402   bool isCastExpr;
2403   ParsedType CastTy;
2404   SourceRange CastRange;
2405   ExprResult Operand = ParseExprAfterUnaryExprOrTypeTrait(OpTok,
2406                                                           isCastExpr,
2407                                                           CastTy,
2408                                                           CastRange);
2409 
2410   UnaryExprOrTypeTrait ExprKind = UETT_SizeOf;
2411   if (OpTok.isOneOf(tok::kw_alignof, tok::kw__Alignof))
2412     ExprKind = UETT_AlignOf;
2413   else if (OpTok.is(tok::kw___alignof))
2414     ExprKind = UETT_PreferredAlignOf;
2415   else if (OpTok.is(tok::kw_vec_step))
2416     ExprKind = UETT_VecStep;
2417   else if (OpTok.is(tok::kw___builtin_omp_required_simd_align))
2418     ExprKind = UETT_OpenMPRequiredSimdAlign;
2419 
2420   if (isCastExpr)
2421     return Actions.ActOnUnaryExprOrTypeTraitExpr(OpTok.getLocation(),
2422                                                  ExprKind,
2423                                                  /*IsType=*/true,
2424                                                  CastTy.getAsOpaquePtr(),
2425                                                  CastRange);
2426 
2427   if (OpTok.isOneOf(tok::kw_alignof, tok::kw__Alignof))
2428     Diag(OpTok, diag::ext_alignof_expr) << OpTok.getIdentifierInfo();
2429 
2430   // If we get here, the operand to the sizeof/alignof was an expression.
2431   if (!Operand.isInvalid())
2432     Operand = Actions.ActOnUnaryExprOrTypeTraitExpr(OpTok.getLocation(),
2433                                                     ExprKind,
2434                                                     /*IsType=*/false,
2435                                                     Operand.get(),
2436                                                     CastRange);
2437   return Operand;
2438 }
2439 
2440 /// ParseBuiltinPrimaryExpression
2441 ///
2442 /// \verbatim
2443 ///       primary-expression: [C99 6.5.1]
2444 /// [GNU]   '__builtin_va_arg' '(' assignment-expression ',' type-name ')'
2445 /// [GNU]   '__builtin_offsetof' '(' type-name ',' offsetof-member-designator')'
2446 /// [GNU]   '__builtin_choose_expr' '(' assign-expr ',' assign-expr ','
2447 ///                                     assign-expr ')'
2448 /// [GNU]   '__builtin_types_compatible_p' '(' type-name ',' type-name ')'
2449 /// [GNU]   '__builtin_FILE' '(' ')'
2450 /// [GNU]   '__builtin_FUNCTION' '(' ')'
2451 /// [GNU]   '__builtin_LINE' '(' ')'
2452 /// [CLANG] '__builtin_COLUMN' '(' ')'
2453 /// [OCL]   '__builtin_astype' '(' assignment-expression ',' type-name ')'
2454 ///
2455 /// [GNU] offsetof-member-designator:
2456 /// [GNU]   identifier
2457 /// [GNU]   offsetof-member-designator '.' identifier
2458 /// [GNU]   offsetof-member-designator '[' expression ']'
2459 /// \endverbatim
ParseBuiltinPrimaryExpression()2460 ExprResult Parser::ParseBuiltinPrimaryExpression() {
2461   ExprResult Res;
2462   const IdentifierInfo *BuiltinII = Tok.getIdentifierInfo();
2463 
2464   tok::TokenKind T = Tok.getKind();
2465   SourceLocation StartLoc = ConsumeToken();   // Eat the builtin identifier.
2466 
2467   // All of these start with an open paren.
2468   if (Tok.isNot(tok::l_paren))
2469     return ExprError(Diag(Tok, diag::err_expected_after) << BuiltinII
2470                                                          << tok::l_paren);
2471 
2472   BalancedDelimiterTracker PT(*this, tok::l_paren);
2473   PT.consumeOpen();
2474 
2475   // TODO: Build AST.
2476 
2477   switch (T) {
2478   default: llvm_unreachable("Not a builtin primary expression!");
2479   case tok::kw___builtin_va_arg: {
2480     ExprResult Expr(ParseAssignmentExpression());
2481 
2482     if (ExpectAndConsume(tok::comma)) {
2483       SkipUntil(tok::r_paren, StopAtSemi);
2484       Expr = ExprError();
2485     }
2486 
2487     TypeResult Ty = ParseTypeName();
2488 
2489     if (Tok.isNot(tok::r_paren)) {
2490       Diag(Tok, diag::err_expected) << tok::r_paren;
2491       Expr = ExprError();
2492     }
2493 
2494     if (Expr.isInvalid() || Ty.isInvalid())
2495       Res = ExprError();
2496     else
2497       Res = Actions.ActOnVAArg(StartLoc, Expr.get(), Ty.get(), ConsumeParen());
2498     break;
2499   }
2500   case tok::kw___builtin_offsetof: {
2501     SourceLocation TypeLoc = Tok.getLocation();
2502     TypeResult Ty = ParseTypeName();
2503     if (Ty.isInvalid()) {
2504       SkipUntil(tok::r_paren, StopAtSemi);
2505       return ExprError();
2506     }
2507 
2508     if (ExpectAndConsume(tok::comma)) {
2509       SkipUntil(tok::r_paren, StopAtSemi);
2510       return ExprError();
2511     }
2512 
2513     // We must have at least one identifier here.
2514     if (Tok.isNot(tok::identifier)) {
2515       Diag(Tok, diag::err_expected) << tok::identifier;
2516       SkipUntil(tok::r_paren, StopAtSemi);
2517       return ExprError();
2518     }
2519 
2520     // Keep track of the various subcomponents we see.
2521     SmallVector<Sema::OffsetOfComponent, 4> Comps;
2522 
2523     Comps.push_back(Sema::OffsetOfComponent());
2524     Comps.back().isBrackets = false;
2525     Comps.back().U.IdentInfo = Tok.getIdentifierInfo();
2526     Comps.back().LocStart = Comps.back().LocEnd = ConsumeToken();
2527 
2528     // FIXME: This loop leaks the index expressions on error.
2529     while (1) {
2530       if (Tok.is(tok::period)) {
2531         // offsetof-member-designator: offsetof-member-designator '.' identifier
2532         Comps.push_back(Sema::OffsetOfComponent());
2533         Comps.back().isBrackets = false;
2534         Comps.back().LocStart = ConsumeToken();
2535 
2536         if (Tok.isNot(tok::identifier)) {
2537           Diag(Tok, diag::err_expected) << tok::identifier;
2538           SkipUntil(tok::r_paren, StopAtSemi);
2539           return ExprError();
2540         }
2541         Comps.back().U.IdentInfo = Tok.getIdentifierInfo();
2542         Comps.back().LocEnd = ConsumeToken();
2543 
2544       } else if (Tok.is(tok::l_square)) {
2545         if (CheckProhibitedCXX11Attribute())
2546           return ExprError();
2547 
2548         // offsetof-member-designator: offsetof-member-design '[' expression ']'
2549         Comps.push_back(Sema::OffsetOfComponent());
2550         Comps.back().isBrackets = true;
2551         BalancedDelimiterTracker ST(*this, tok::l_square);
2552         ST.consumeOpen();
2553         Comps.back().LocStart = ST.getOpenLocation();
2554         Res = ParseExpression();
2555         if (Res.isInvalid()) {
2556           SkipUntil(tok::r_paren, StopAtSemi);
2557           return Res;
2558         }
2559         Comps.back().U.E = Res.get();
2560 
2561         ST.consumeClose();
2562         Comps.back().LocEnd = ST.getCloseLocation();
2563       } else {
2564         if (Tok.isNot(tok::r_paren)) {
2565           PT.consumeClose();
2566           Res = ExprError();
2567         } else if (Ty.isInvalid()) {
2568           Res = ExprError();
2569         } else {
2570           PT.consumeClose();
2571           Res = Actions.ActOnBuiltinOffsetOf(getCurScope(), StartLoc, TypeLoc,
2572                                              Ty.get(), Comps,
2573                                              PT.getCloseLocation());
2574         }
2575         break;
2576       }
2577     }
2578     break;
2579   }
2580   case tok::kw___builtin_choose_expr: {
2581     ExprResult Cond(ParseAssignmentExpression());
2582     if (Cond.isInvalid()) {
2583       SkipUntil(tok::r_paren, StopAtSemi);
2584       return Cond;
2585     }
2586     if (ExpectAndConsume(tok::comma)) {
2587       SkipUntil(tok::r_paren, StopAtSemi);
2588       return ExprError();
2589     }
2590 
2591     ExprResult Expr1(ParseAssignmentExpression());
2592     if (Expr1.isInvalid()) {
2593       SkipUntil(tok::r_paren, StopAtSemi);
2594       return Expr1;
2595     }
2596     if (ExpectAndConsume(tok::comma)) {
2597       SkipUntil(tok::r_paren, StopAtSemi);
2598       return ExprError();
2599     }
2600 
2601     ExprResult Expr2(ParseAssignmentExpression());
2602     if (Expr2.isInvalid()) {
2603       SkipUntil(tok::r_paren, StopAtSemi);
2604       return Expr2;
2605     }
2606     if (Tok.isNot(tok::r_paren)) {
2607       Diag(Tok, diag::err_expected) << tok::r_paren;
2608       return ExprError();
2609     }
2610     Res = Actions.ActOnChooseExpr(StartLoc, Cond.get(), Expr1.get(),
2611                                   Expr2.get(), ConsumeParen());
2612     break;
2613   }
2614   case tok::kw___builtin_astype: {
2615     // The first argument is an expression to be converted, followed by a comma.
2616     ExprResult Expr(ParseAssignmentExpression());
2617     if (Expr.isInvalid()) {
2618       SkipUntil(tok::r_paren, StopAtSemi);
2619       return ExprError();
2620     }
2621 
2622     if (ExpectAndConsume(tok::comma)) {
2623       SkipUntil(tok::r_paren, StopAtSemi);
2624       return ExprError();
2625     }
2626 
2627     // Second argument is the type to bitcast to.
2628     TypeResult DestTy = ParseTypeName();
2629     if (DestTy.isInvalid())
2630       return ExprError();
2631 
2632     // Attempt to consume the r-paren.
2633     if (Tok.isNot(tok::r_paren)) {
2634       Diag(Tok, diag::err_expected) << tok::r_paren;
2635       SkipUntil(tok::r_paren, StopAtSemi);
2636       return ExprError();
2637     }
2638 
2639     Res = Actions.ActOnAsTypeExpr(Expr.get(), DestTy.get(), StartLoc,
2640                                   ConsumeParen());
2641     break;
2642   }
2643   case tok::kw___builtin_convertvector: {
2644     // The first argument is an expression to be converted, followed by a comma.
2645     ExprResult Expr(ParseAssignmentExpression());
2646     if (Expr.isInvalid()) {
2647       SkipUntil(tok::r_paren, StopAtSemi);
2648       return ExprError();
2649     }
2650 
2651     if (ExpectAndConsume(tok::comma)) {
2652       SkipUntil(tok::r_paren, StopAtSemi);
2653       return ExprError();
2654     }
2655 
2656     // Second argument is the type to bitcast to.
2657     TypeResult DestTy = ParseTypeName();
2658     if (DestTy.isInvalid())
2659       return ExprError();
2660 
2661     // Attempt to consume the r-paren.
2662     if (Tok.isNot(tok::r_paren)) {
2663       Diag(Tok, diag::err_expected) << tok::r_paren;
2664       SkipUntil(tok::r_paren, StopAtSemi);
2665       return ExprError();
2666     }
2667 
2668     Res = Actions.ActOnConvertVectorExpr(Expr.get(), DestTy.get(), StartLoc,
2669                                          ConsumeParen());
2670     break;
2671   }
2672   case tok::kw___builtin_COLUMN:
2673   case tok::kw___builtin_FILE:
2674   case tok::kw___builtin_FUNCTION:
2675   case tok::kw___builtin_LINE: {
2676     // Attempt to consume the r-paren.
2677     if (Tok.isNot(tok::r_paren)) {
2678       Diag(Tok, diag::err_expected) << tok::r_paren;
2679       SkipUntil(tok::r_paren, StopAtSemi);
2680       return ExprError();
2681     }
2682     SourceLocExpr::IdentKind Kind = [&] {
2683       switch (T) {
2684       case tok::kw___builtin_FILE:
2685         return SourceLocExpr::File;
2686       case tok::kw___builtin_FUNCTION:
2687         return SourceLocExpr::Function;
2688       case tok::kw___builtin_LINE:
2689         return SourceLocExpr::Line;
2690       case tok::kw___builtin_COLUMN:
2691         return SourceLocExpr::Column;
2692       default:
2693         llvm_unreachable("invalid keyword");
2694       }
2695     }();
2696     Res = Actions.ActOnSourceLocExpr(Kind, StartLoc, ConsumeParen());
2697     break;
2698   }
2699   }
2700 
2701   if (Res.isInvalid())
2702     return ExprError();
2703 
2704   // These can be followed by postfix-expr pieces because they are
2705   // primary-expressions.
2706   return ParsePostfixExpressionSuffix(Res.get());
2707 }
2708 
tryParseOpenMPArrayShapingCastPart()2709 bool Parser::tryParseOpenMPArrayShapingCastPart() {
2710   assert(Tok.is(tok::l_square) && "Expected open bracket");
2711   bool ErrorFound = true;
2712   TentativeParsingAction TPA(*this);
2713   do {
2714     if (Tok.isNot(tok::l_square))
2715       break;
2716     // Consume '['
2717     ConsumeBracket();
2718     // Skip inner expression.
2719     while (!SkipUntil(tok::r_square, tok::annot_pragma_openmp_end,
2720                       StopAtSemi | StopBeforeMatch))
2721       ;
2722     if (Tok.isNot(tok::r_square))
2723       break;
2724     // Consume ']'
2725     ConsumeBracket();
2726     // Found ')' - done.
2727     if (Tok.is(tok::r_paren)) {
2728       ErrorFound = false;
2729       break;
2730     }
2731   } while (Tok.isNot(tok::annot_pragma_openmp_end));
2732   TPA.Revert();
2733   return !ErrorFound;
2734 }
2735 
2736 /// ParseParenExpression - This parses the unit that starts with a '(' token,
2737 /// based on what is allowed by ExprType.  The actual thing parsed is returned
2738 /// in ExprType. If stopIfCastExpr is true, it will only return the parsed type,
2739 /// not the parsed cast-expression.
2740 ///
2741 /// \verbatim
2742 ///       primary-expression: [C99 6.5.1]
2743 ///         '(' expression ')'
2744 /// [GNU]   '(' compound-statement ')'      (if !ParenExprOnly)
2745 ///       postfix-expression: [C99 6.5.2]
2746 ///         '(' type-name ')' '{' initializer-list '}'
2747 ///         '(' type-name ')' '{' initializer-list ',' '}'
2748 ///       cast-expression: [C99 6.5.4]
2749 ///         '(' type-name ')' cast-expression
2750 /// [ARC]   bridged-cast-expression
2751 /// [ARC] bridged-cast-expression:
2752 ///         (__bridge type-name) cast-expression
2753 ///         (__bridge_transfer type-name) cast-expression
2754 ///         (__bridge_retained type-name) cast-expression
2755 ///       fold-expression: [C++1z]
2756 ///         '(' cast-expression fold-operator '...' ')'
2757 ///         '(' '...' fold-operator cast-expression ')'
2758 ///         '(' cast-expression fold-operator '...'
2759 ///                 fold-operator cast-expression ')'
2760 /// [OPENMP] Array shaping operation
2761 ///       '(' '[' expression ']' { '[' expression ']' } cast-expression
2762 /// \endverbatim
2763 ExprResult
ParseParenExpression(ParenParseOption & ExprType,bool stopIfCastExpr,bool isTypeCast,ParsedType & CastTy,SourceLocation & RParenLoc)2764 Parser::ParseParenExpression(ParenParseOption &ExprType, bool stopIfCastExpr,
2765                              bool isTypeCast, ParsedType &CastTy,
2766                              SourceLocation &RParenLoc) {
2767   assert(Tok.is(tok::l_paren) && "Not a paren expr!");
2768   ColonProtectionRAIIObject ColonProtection(*this, false);
2769   BalancedDelimiterTracker T(*this, tok::l_paren);
2770   if (T.consumeOpen())
2771     return ExprError();
2772   SourceLocation OpenLoc = T.getOpenLocation();
2773 
2774   PreferredType.enterParenExpr(Tok.getLocation(), OpenLoc);
2775 
2776   ExprResult Result(true);
2777   bool isAmbiguousTypeId;
2778   CastTy = nullptr;
2779 
2780   if (Tok.is(tok::code_completion)) {
2781     cutOffParsing();
2782     Actions.CodeCompleteExpression(
2783         getCurScope(), PreferredType.get(Tok.getLocation()),
2784         /*IsParenthesized=*/ExprType >= CompoundLiteral);
2785     return ExprError();
2786   }
2787 
2788   // Diagnose use of bridge casts in non-arc mode.
2789   bool BridgeCast = (getLangOpts().ObjC &&
2790                      Tok.isOneOf(tok::kw___bridge,
2791                                  tok::kw___bridge_transfer,
2792                                  tok::kw___bridge_retained,
2793                                  tok::kw___bridge_retain));
2794   if (BridgeCast && !getLangOpts().ObjCAutoRefCount) {
2795     if (!TryConsumeToken(tok::kw___bridge)) {
2796       StringRef BridgeCastName = Tok.getName();
2797       SourceLocation BridgeKeywordLoc = ConsumeToken();
2798       if (!PP.getSourceManager().isInSystemHeader(BridgeKeywordLoc))
2799         Diag(BridgeKeywordLoc, diag::warn_arc_bridge_cast_nonarc)
2800           << BridgeCastName
2801           << FixItHint::CreateReplacement(BridgeKeywordLoc, "");
2802     }
2803     BridgeCast = false;
2804   }
2805 
2806   // None of these cases should fall through with an invalid Result
2807   // unless they've already reported an error.
2808   if (ExprType >= CompoundStmt && Tok.is(tok::l_brace)) {
2809     Diag(Tok, diag::ext_gnu_statement_expr);
2810 
2811     checkCompoundToken(OpenLoc, tok::l_paren, CompoundToken::StmtExprBegin);
2812 
2813     if (!getCurScope()->getFnParent() && !getCurScope()->getBlockParent()) {
2814       Result = ExprError(Diag(OpenLoc, diag::err_stmtexpr_file_scope));
2815     } else {
2816       // Find the nearest non-record decl context. Variables declared in a
2817       // statement expression behave as if they were declared in the enclosing
2818       // function, block, or other code construct.
2819       DeclContext *CodeDC = Actions.CurContext;
2820       while (CodeDC->isRecord() || isa<EnumDecl>(CodeDC)) {
2821         CodeDC = CodeDC->getParent();
2822         assert(CodeDC && !CodeDC->isFileContext() &&
2823                "statement expr not in code context");
2824       }
2825       Sema::ContextRAII SavedContext(Actions, CodeDC, /*NewThisContext=*/false);
2826 
2827       Actions.ActOnStartStmtExpr();
2828 
2829       StmtResult Stmt(ParseCompoundStatement(true));
2830       ExprType = CompoundStmt;
2831 
2832       // If the substmt parsed correctly, build the AST node.
2833       if (!Stmt.isInvalid()) {
2834         Result = Actions.ActOnStmtExpr(getCurScope(), OpenLoc, Stmt.get(),
2835                                        Tok.getLocation());
2836       } else {
2837         Actions.ActOnStmtExprError();
2838       }
2839     }
2840   } else if (ExprType >= CompoundLiteral && BridgeCast) {
2841     tok::TokenKind tokenKind = Tok.getKind();
2842     SourceLocation BridgeKeywordLoc = ConsumeToken();
2843 
2844     // Parse an Objective-C ARC ownership cast expression.
2845     ObjCBridgeCastKind Kind;
2846     if (tokenKind == tok::kw___bridge)
2847       Kind = OBC_Bridge;
2848     else if (tokenKind == tok::kw___bridge_transfer)
2849       Kind = OBC_BridgeTransfer;
2850     else if (tokenKind == tok::kw___bridge_retained)
2851       Kind = OBC_BridgeRetained;
2852     else {
2853       // As a hopefully temporary workaround, allow __bridge_retain as
2854       // a synonym for __bridge_retained, but only in system headers.
2855       assert(tokenKind == tok::kw___bridge_retain);
2856       Kind = OBC_BridgeRetained;
2857       if (!PP.getSourceManager().isInSystemHeader(BridgeKeywordLoc))
2858         Diag(BridgeKeywordLoc, diag::err_arc_bridge_retain)
2859           << FixItHint::CreateReplacement(BridgeKeywordLoc,
2860                                           "__bridge_retained");
2861     }
2862 
2863     TypeResult Ty = ParseTypeName();
2864     T.consumeClose();
2865     ColonProtection.restore();
2866     RParenLoc = T.getCloseLocation();
2867 
2868     PreferredType.enterTypeCast(Tok.getLocation(), Ty.get().get());
2869     ExprResult SubExpr = ParseCastExpression(AnyCastExpr);
2870 
2871     if (Ty.isInvalid() || SubExpr.isInvalid())
2872       return ExprError();
2873 
2874     return Actions.ActOnObjCBridgedCast(getCurScope(), OpenLoc, Kind,
2875                                         BridgeKeywordLoc, Ty.get(),
2876                                         RParenLoc, SubExpr.get());
2877   } else if (ExprType >= CompoundLiteral &&
2878              isTypeIdInParens(isAmbiguousTypeId)) {
2879 
2880     // Otherwise, this is a compound literal expression or cast expression.
2881 
2882     // In C++, if the type-id is ambiguous we disambiguate based on context.
2883     // If stopIfCastExpr is true the context is a typeof/sizeof/alignof
2884     // in which case we should treat it as type-id.
2885     // if stopIfCastExpr is false, we need to determine the context past the
2886     // parens, so we defer to ParseCXXAmbiguousParenExpression for that.
2887     if (isAmbiguousTypeId && !stopIfCastExpr) {
2888       ExprResult res = ParseCXXAmbiguousParenExpression(ExprType, CastTy, T,
2889                                                         ColonProtection);
2890       RParenLoc = T.getCloseLocation();
2891       return res;
2892     }
2893 
2894     // Parse the type declarator.
2895     DeclSpec DS(AttrFactory);
2896     ParseSpecifierQualifierList(DS);
2897     Declarator DeclaratorInfo(DS, DeclaratorContext::TypeName);
2898     ParseDeclarator(DeclaratorInfo);
2899 
2900     // If our type is followed by an identifier and either ':' or ']', then
2901     // this is probably an Objective-C message send where the leading '[' is
2902     // missing. Recover as if that were the case.
2903     if (!DeclaratorInfo.isInvalidType() && Tok.is(tok::identifier) &&
2904         !InMessageExpression && getLangOpts().ObjC &&
2905         (NextToken().is(tok::colon) || NextToken().is(tok::r_square))) {
2906       TypeResult Ty;
2907       {
2908         InMessageExpressionRAIIObject InMessage(*this, false);
2909         Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
2910       }
2911       Result = ParseObjCMessageExpressionBody(SourceLocation(),
2912                                               SourceLocation(),
2913                                               Ty.get(), nullptr);
2914     } else {
2915       // Match the ')'.
2916       T.consumeClose();
2917       ColonProtection.restore();
2918       RParenLoc = T.getCloseLocation();
2919       if (Tok.is(tok::l_brace)) {
2920         ExprType = CompoundLiteral;
2921         TypeResult Ty;
2922         {
2923           InMessageExpressionRAIIObject InMessage(*this, false);
2924           Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
2925         }
2926         return ParseCompoundLiteralExpression(Ty.get(), OpenLoc, RParenLoc);
2927       }
2928 
2929       if (Tok.is(tok::l_paren)) {
2930         // This could be OpenCL vector Literals
2931         if (getLangOpts().OpenCL)
2932         {
2933           TypeResult Ty;
2934           {
2935             InMessageExpressionRAIIObject InMessage(*this, false);
2936             Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
2937           }
2938           if(Ty.isInvalid())
2939           {
2940              return ExprError();
2941           }
2942           QualType QT = Ty.get().get().getCanonicalType();
2943           if (QT->isVectorType())
2944           {
2945             // We parsed '(' vector-type-name ')' followed by '('
2946 
2947             // Parse the cast-expression that follows it next.
2948             // isVectorLiteral = true will make sure we don't parse any
2949             // Postfix expression yet
2950             Result = ParseCastExpression(/*isUnaryExpression=*/AnyCastExpr,
2951                                          /*isAddressOfOperand=*/false,
2952                                          /*isTypeCast=*/IsTypeCast,
2953                                          /*isVectorLiteral=*/true);
2954 
2955             if (!Result.isInvalid()) {
2956               Result = Actions.ActOnCastExpr(getCurScope(), OpenLoc,
2957                                              DeclaratorInfo, CastTy,
2958                                              RParenLoc, Result.get());
2959             }
2960 
2961             // After we performed the cast we can check for postfix-expr pieces.
2962             if (!Result.isInvalid()) {
2963               Result = ParsePostfixExpressionSuffix(Result);
2964             }
2965 
2966             return Result;
2967           }
2968         }
2969       }
2970 
2971       if (ExprType == CastExpr) {
2972         // We parsed '(' type-name ')' and the thing after it wasn't a '{'.
2973 
2974         if (DeclaratorInfo.isInvalidType())
2975           return ExprError();
2976 
2977         // Note that this doesn't parse the subsequent cast-expression, it just
2978         // returns the parsed type to the callee.
2979         if (stopIfCastExpr) {
2980           TypeResult Ty;
2981           {
2982             InMessageExpressionRAIIObject InMessage(*this, false);
2983             Ty = Actions.ActOnTypeName(getCurScope(), DeclaratorInfo);
2984           }
2985           CastTy = Ty.get();
2986           return ExprResult();
2987         }
2988 
2989         // Reject the cast of super idiom in ObjC.
2990         if (Tok.is(tok::identifier) && getLangOpts().ObjC &&
2991             Tok.getIdentifierInfo() == Ident_super &&
2992             getCurScope()->isInObjcMethodScope() &&
2993             GetLookAheadToken(1).isNot(tok::period)) {
2994           Diag(Tok.getLocation(), diag::err_illegal_super_cast)
2995             << SourceRange(OpenLoc, RParenLoc);
2996           return ExprError();
2997         }
2998 
2999         PreferredType.enterTypeCast(Tok.getLocation(), CastTy.get());
3000         // Parse the cast-expression that follows it next.
3001         // TODO: For cast expression with CastTy.
3002         Result = ParseCastExpression(/*isUnaryExpression=*/AnyCastExpr,
3003                                      /*isAddressOfOperand=*/false,
3004                                      /*isTypeCast=*/IsTypeCast);
3005         if (!Result.isInvalid()) {
3006           Result = Actions.ActOnCastExpr(getCurScope(), OpenLoc,
3007                                          DeclaratorInfo, CastTy,
3008                                          RParenLoc, Result.get());
3009         }
3010         return Result;
3011       }
3012 
3013       Diag(Tok, diag::err_expected_lbrace_in_compound_literal);
3014       return ExprError();
3015     }
3016   } else if (ExprType >= FoldExpr && Tok.is(tok::ellipsis) &&
3017              isFoldOperator(NextToken().getKind())) {
3018     ExprType = FoldExpr;
3019     return ParseFoldExpression(ExprResult(), T);
3020   } else if (isTypeCast) {
3021     // Parse the expression-list.
3022     InMessageExpressionRAIIObject InMessage(*this, false);
3023 
3024     ExprVector ArgExprs;
3025     CommaLocsTy CommaLocs;
3026 
3027     if (!ParseSimpleExpressionList(ArgExprs, CommaLocs)) {
3028       // FIXME: If we ever support comma expressions as operands to
3029       // fold-expressions, we'll need to allow multiple ArgExprs here.
3030       if (ExprType >= FoldExpr && ArgExprs.size() == 1 &&
3031           isFoldOperator(Tok.getKind()) && NextToken().is(tok::ellipsis)) {
3032         ExprType = FoldExpr;
3033         return ParseFoldExpression(ArgExprs[0], T);
3034       }
3035 
3036       ExprType = SimpleExpr;
3037       Result = Actions.ActOnParenListExpr(OpenLoc, Tok.getLocation(),
3038                                           ArgExprs);
3039     }
3040   } else if (getLangOpts().OpenMP >= 50 && OpenMPDirectiveParsing &&
3041              ExprType == CastExpr && Tok.is(tok::l_square) &&
3042              tryParseOpenMPArrayShapingCastPart()) {
3043     bool ErrorFound = false;
3044     SmallVector<Expr *, 4> OMPDimensions;
3045     SmallVector<SourceRange, 4> OMPBracketsRanges;
3046     do {
3047       BalancedDelimiterTracker TS(*this, tok::l_square);
3048       TS.consumeOpen();
3049       ExprResult NumElements =
3050           Actions.CorrectDelayedTyposInExpr(ParseExpression());
3051       if (!NumElements.isUsable()) {
3052         ErrorFound = true;
3053         while (!SkipUntil(tok::r_square, tok::r_paren,
3054                           StopAtSemi | StopBeforeMatch))
3055           ;
3056       }
3057       TS.consumeClose();
3058       OMPDimensions.push_back(NumElements.get());
3059       OMPBracketsRanges.push_back(TS.getRange());
3060     } while (Tok.isNot(tok::r_paren));
3061     // Match the ')'.
3062     T.consumeClose();
3063     RParenLoc = T.getCloseLocation();
3064     Result = Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression());
3065     if (ErrorFound) {
3066       Result = ExprError();
3067     } else if (!Result.isInvalid()) {
3068       Result = Actions.ActOnOMPArrayShapingExpr(
3069           Result.get(), OpenLoc, RParenLoc, OMPDimensions, OMPBracketsRanges);
3070     }
3071     return Result;
3072   } else {
3073     InMessageExpressionRAIIObject InMessage(*this, false);
3074 
3075     Result = ParseExpression(MaybeTypeCast);
3076     if (!getLangOpts().CPlusPlus && MaybeTypeCast && Result.isUsable()) {
3077       // Correct typos in non-C++ code earlier so that implicit-cast-like
3078       // expressions are parsed correctly.
3079       Result = Actions.CorrectDelayedTyposInExpr(Result);
3080     }
3081 
3082     if (ExprType >= FoldExpr && isFoldOperator(Tok.getKind()) &&
3083         NextToken().is(tok::ellipsis)) {
3084       ExprType = FoldExpr;
3085       return ParseFoldExpression(Result, T);
3086     }
3087     ExprType = SimpleExpr;
3088 
3089     // Don't build a paren expression unless we actually match a ')'.
3090     if (!Result.isInvalid() && Tok.is(tok::r_paren))
3091       Result =
3092           Actions.ActOnParenExpr(OpenLoc, Tok.getLocation(), Result.get());
3093   }
3094 
3095   // Match the ')'.
3096   if (Result.isInvalid()) {
3097     SkipUntil(tok::r_paren, StopAtSemi);
3098     return ExprError();
3099   }
3100 
3101   T.consumeClose();
3102   RParenLoc = T.getCloseLocation();
3103   return Result;
3104 }
3105 
3106 /// ParseCompoundLiteralExpression - We have parsed the parenthesized type-name
3107 /// and we are at the left brace.
3108 ///
3109 /// \verbatim
3110 ///       postfix-expression: [C99 6.5.2]
3111 ///         '(' type-name ')' '{' initializer-list '}'
3112 ///         '(' type-name ')' '{' initializer-list ',' '}'
3113 /// \endverbatim
3114 ExprResult
ParseCompoundLiteralExpression(ParsedType Ty,SourceLocation LParenLoc,SourceLocation RParenLoc)3115 Parser::ParseCompoundLiteralExpression(ParsedType Ty,
3116                                        SourceLocation LParenLoc,
3117                                        SourceLocation RParenLoc) {
3118   assert(Tok.is(tok::l_brace) && "Not a compound literal!");
3119   if (!getLangOpts().C99)   // Compound literals don't exist in C90.
3120     Diag(LParenLoc, diag::ext_c99_compound_literal);
3121   PreferredType.enterTypeCast(Tok.getLocation(), Ty.get());
3122   ExprResult Result = ParseInitializer();
3123   if (!Result.isInvalid() && Ty)
3124     return Actions.ActOnCompoundLiteral(LParenLoc, Ty, RParenLoc, Result.get());
3125   return Result;
3126 }
3127 
3128 /// ParseStringLiteralExpression - This handles the various token types that
3129 /// form string literals, and also handles string concatenation [C99 5.1.1.2,
3130 /// translation phase #6].
3131 ///
3132 /// \verbatim
3133 ///       primary-expression: [C99 6.5.1]
3134 ///         string-literal
3135 /// \verbatim
ParseStringLiteralExpression(bool AllowUserDefinedLiteral)3136 ExprResult Parser::ParseStringLiteralExpression(bool AllowUserDefinedLiteral) {
3137   assert(isTokenStringLiteral() && "Not a string literal!");
3138 
3139   // String concat.  Note that keywords like __func__ and __FUNCTION__ are not
3140   // considered to be strings for concatenation purposes.
3141   SmallVector<Token, 4> StringToks;
3142 
3143   do {
3144     StringToks.push_back(Tok);
3145     ConsumeStringToken();
3146   } while (isTokenStringLiteral());
3147 
3148   // Pass the set of string tokens, ready for concatenation, to the actions.
3149   return Actions.ActOnStringLiteral(StringToks,
3150                                     AllowUserDefinedLiteral ? getCurScope()
3151                                                             : nullptr);
3152 }
3153 
3154 /// ParseGenericSelectionExpression - Parse a C11 generic-selection
3155 /// [C11 6.5.1.1].
3156 ///
3157 /// \verbatim
3158 ///    generic-selection:
3159 ///           _Generic ( assignment-expression , generic-assoc-list )
3160 ///    generic-assoc-list:
3161 ///           generic-association
3162 ///           generic-assoc-list , generic-association
3163 ///    generic-association:
3164 ///           type-name : assignment-expression
3165 ///           default : assignment-expression
3166 /// \endverbatim
ParseGenericSelectionExpression()3167 ExprResult Parser::ParseGenericSelectionExpression() {
3168   assert(Tok.is(tok::kw__Generic) && "_Generic keyword expected");
3169   if (!getLangOpts().C11)
3170     Diag(Tok, diag::ext_c11_feature) << Tok.getName();
3171 
3172   SourceLocation KeyLoc = ConsumeToken();
3173   BalancedDelimiterTracker T(*this, tok::l_paren);
3174   if (T.expectAndConsume())
3175     return ExprError();
3176 
3177   ExprResult ControllingExpr;
3178   {
3179     // C11 6.5.1.1p3 "The controlling expression of a generic selection is
3180     // not evaluated."
3181     EnterExpressionEvaluationContext Unevaluated(
3182         Actions, Sema::ExpressionEvaluationContext::Unevaluated);
3183     ControllingExpr =
3184         Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression());
3185     if (ControllingExpr.isInvalid()) {
3186       SkipUntil(tok::r_paren, StopAtSemi);
3187       return ExprError();
3188     }
3189   }
3190 
3191   if (ExpectAndConsume(tok::comma)) {
3192     SkipUntil(tok::r_paren, StopAtSemi);
3193     return ExprError();
3194   }
3195 
3196   SourceLocation DefaultLoc;
3197   TypeVector Types;
3198   ExprVector Exprs;
3199   do {
3200     ParsedType Ty;
3201     if (Tok.is(tok::kw_default)) {
3202       // C11 6.5.1.1p2 "A generic selection shall have no more than one default
3203       // generic association."
3204       if (!DefaultLoc.isInvalid()) {
3205         Diag(Tok, diag::err_duplicate_default_assoc);
3206         Diag(DefaultLoc, diag::note_previous_default_assoc);
3207         SkipUntil(tok::r_paren, StopAtSemi);
3208         return ExprError();
3209       }
3210       DefaultLoc = ConsumeToken();
3211       Ty = nullptr;
3212     } else {
3213       ColonProtectionRAIIObject X(*this);
3214       TypeResult TR = ParseTypeName();
3215       if (TR.isInvalid()) {
3216         SkipUntil(tok::r_paren, StopAtSemi);
3217         return ExprError();
3218       }
3219       Ty = TR.get();
3220     }
3221     Types.push_back(Ty);
3222 
3223     if (ExpectAndConsume(tok::colon)) {
3224       SkipUntil(tok::r_paren, StopAtSemi);
3225       return ExprError();
3226     }
3227 
3228     // FIXME: These expressions should be parsed in a potentially potentially
3229     // evaluated context.
3230     ExprResult ER(
3231         Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression()));
3232     if (ER.isInvalid()) {
3233       SkipUntil(tok::r_paren, StopAtSemi);
3234       return ExprError();
3235     }
3236     Exprs.push_back(ER.get());
3237   } while (TryConsumeToken(tok::comma));
3238 
3239   T.consumeClose();
3240   if (T.getCloseLocation().isInvalid())
3241     return ExprError();
3242 
3243   return Actions.ActOnGenericSelectionExpr(KeyLoc, DefaultLoc,
3244                                            T.getCloseLocation(),
3245                                            ControllingExpr.get(),
3246                                            Types, Exprs);
3247 }
3248 
3249 /// Parse A C++1z fold-expression after the opening paren and optional
3250 /// left-hand-side expression.
3251 ///
3252 /// \verbatim
3253 ///   fold-expression:
3254 ///       ( cast-expression fold-operator ... )
3255 ///       ( ... fold-operator cast-expression )
3256 ///       ( cast-expression fold-operator ... fold-operator cast-expression )
ParseFoldExpression(ExprResult LHS,BalancedDelimiterTracker & T)3257 ExprResult Parser::ParseFoldExpression(ExprResult LHS,
3258                                        BalancedDelimiterTracker &T) {
3259   if (LHS.isInvalid()) {
3260     T.skipToEnd();
3261     return true;
3262   }
3263 
3264   tok::TokenKind Kind = tok::unknown;
3265   SourceLocation FirstOpLoc;
3266   if (LHS.isUsable()) {
3267     Kind = Tok.getKind();
3268     assert(isFoldOperator(Kind) && "missing fold-operator");
3269     FirstOpLoc = ConsumeToken();
3270   }
3271 
3272   assert(Tok.is(tok::ellipsis) && "not a fold-expression");
3273   SourceLocation EllipsisLoc = ConsumeToken();
3274 
3275   ExprResult RHS;
3276   if (Tok.isNot(tok::r_paren)) {
3277     if (!isFoldOperator(Tok.getKind()))
3278       return Diag(Tok.getLocation(), diag::err_expected_fold_operator);
3279 
3280     if (Kind != tok::unknown && Tok.getKind() != Kind)
3281       Diag(Tok.getLocation(), diag::err_fold_operator_mismatch)
3282         << SourceRange(FirstOpLoc);
3283     Kind = Tok.getKind();
3284     ConsumeToken();
3285 
3286     RHS = ParseExpression();
3287     if (RHS.isInvalid()) {
3288       T.skipToEnd();
3289       return true;
3290     }
3291   }
3292 
3293   Diag(EllipsisLoc, getLangOpts().CPlusPlus17
3294                         ? diag::warn_cxx14_compat_fold_expression
3295                         : diag::ext_fold_expression);
3296 
3297   T.consumeClose();
3298   return Actions.ActOnCXXFoldExpr(getCurScope(), T.getOpenLocation(), LHS.get(),
3299                                   Kind, EllipsisLoc, RHS.get(),
3300                                   T.getCloseLocation());
3301 }
3302 
3303 /// ParseExpressionList - Used for C/C++ (argument-)expression-list.
3304 ///
3305 /// \verbatim
3306 ///       argument-expression-list:
3307 ///         assignment-expression
3308 ///         argument-expression-list , assignment-expression
3309 ///
3310 /// [C++] expression-list:
3311 /// [C++]   assignment-expression
3312 /// [C++]   expression-list , assignment-expression
3313 ///
3314 /// [C++0x] expression-list:
3315 /// [C++0x]   initializer-list
3316 ///
3317 /// [C++0x] initializer-list
3318 /// [C++0x]   initializer-clause ...[opt]
3319 /// [C++0x]   initializer-list , initializer-clause ...[opt]
3320 ///
3321 /// [C++0x] initializer-clause:
3322 /// [C++0x]   assignment-expression
3323 /// [C++0x]   braced-init-list
3324 /// \endverbatim
ParseExpressionList(SmallVectorImpl<Expr * > & Exprs,SmallVectorImpl<SourceLocation> & CommaLocs,llvm::function_ref<void ()> ExpressionStarts)3325 bool Parser::ParseExpressionList(SmallVectorImpl<Expr *> &Exprs,
3326                                  SmallVectorImpl<SourceLocation> &CommaLocs,
3327                                  llvm::function_ref<void()> ExpressionStarts) {
3328   bool SawError = false;
3329   while (1) {
3330     if (ExpressionStarts)
3331       ExpressionStarts();
3332 
3333     ExprResult Expr;
3334     if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
3335       Diag(Tok, diag::warn_cxx98_compat_generalized_initializer_lists);
3336       Expr = ParseBraceInitializer();
3337     } else
3338       Expr = ParseAssignmentExpression();
3339 
3340     if (Tok.is(tok::ellipsis))
3341       Expr = Actions.ActOnPackExpansion(Expr.get(), ConsumeToken());
3342     else if (Tok.is(tok::code_completion)) {
3343       // There's nothing to suggest in here as we parsed a full expression.
3344       // Instead fail and propogate the error since caller might have something
3345       // the suggest, e.g. signature help in function call. Note that this is
3346       // performed before pushing the \p Expr, so that signature help can report
3347       // current argument correctly.
3348       SawError = true;
3349       cutOffParsing();
3350       break;
3351     }
3352     if (Expr.isInvalid()) {
3353       SkipUntil(tok::comma, tok::r_paren, StopBeforeMatch);
3354       SawError = true;
3355     } else {
3356       Exprs.push_back(Expr.get());
3357     }
3358 
3359     if (Tok.isNot(tok::comma))
3360       break;
3361     // Move to the next argument, remember where the comma was.
3362     Token Comma = Tok;
3363     CommaLocs.push_back(ConsumeToken());
3364 
3365     checkPotentialAngleBracketDelimiter(Comma);
3366   }
3367   if (SawError) {
3368     // Ensure typos get diagnosed when errors were encountered while parsing the
3369     // expression list.
3370     for (auto &E : Exprs) {
3371       ExprResult Expr = Actions.CorrectDelayedTyposInExpr(E);
3372       if (Expr.isUsable()) E = Expr.get();
3373     }
3374   }
3375   return SawError;
3376 }
3377 
3378 /// ParseSimpleExpressionList - A simple comma-separated list of expressions,
3379 /// used for misc language extensions.
3380 ///
3381 /// \verbatim
3382 ///       simple-expression-list:
3383 ///         assignment-expression
3384 ///         simple-expression-list , assignment-expression
3385 /// \endverbatim
3386 bool
ParseSimpleExpressionList(SmallVectorImpl<Expr * > & Exprs,SmallVectorImpl<SourceLocation> & CommaLocs)3387 Parser::ParseSimpleExpressionList(SmallVectorImpl<Expr*> &Exprs,
3388                                   SmallVectorImpl<SourceLocation> &CommaLocs) {
3389   while (1) {
3390     ExprResult Expr = ParseAssignmentExpression();
3391     if (Expr.isInvalid())
3392       return true;
3393 
3394     Exprs.push_back(Expr.get());
3395 
3396     if (Tok.isNot(tok::comma))
3397       return false;
3398 
3399     // Move to the next argument, remember where the comma was.
3400     Token Comma = Tok;
3401     CommaLocs.push_back(ConsumeToken());
3402 
3403     checkPotentialAngleBracketDelimiter(Comma);
3404   }
3405 }
3406 
3407 /// ParseBlockId - Parse a block-id, which roughly looks like int (int x).
3408 ///
3409 /// \verbatim
3410 /// [clang] block-id:
3411 /// [clang]   specifier-qualifier-list block-declarator
3412 /// \endverbatim
ParseBlockId(SourceLocation CaretLoc)3413 void Parser::ParseBlockId(SourceLocation CaretLoc) {
3414   if (Tok.is(tok::code_completion)) {
3415     cutOffParsing();
3416     Actions.CodeCompleteOrdinaryName(getCurScope(), Sema::PCC_Type);
3417     return;
3418   }
3419 
3420   // Parse the specifier-qualifier-list piece.
3421   DeclSpec DS(AttrFactory);
3422   ParseSpecifierQualifierList(DS);
3423 
3424   // Parse the block-declarator.
3425   Declarator DeclaratorInfo(DS, DeclaratorContext::BlockLiteral);
3426   DeclaratorInfo.setFunctionDefinitionKind(FunctionDefinitionKind::Definition);
3427   ParseDeclarator(DeclaratorInfo);
3428 
3429   MaybeParseGNUAttributes(DeclaratorInfo);
3430 
3431   // Inform sema that we are starting a block.
3432   Actions.ActOnBlockArguments(CaretLoc, DeclaratorInfo, getCurScope());
3433 }
3434 
3435 /// ParseBlockLiteralExpression - Parse a block literal, which roughly looks
3436 /// like ^(int x){ return x+1; }
3437 ///
3438 /// \verbatim
3439 ///         block-literal:
3440 /// [clang]   '^' block-args[opt] compound-statement
3441 /// [clang]   '^' block-id compound-statement
3442 /// [clang] block-args:
3443 /// [clang]   '(' parameter-list ')'
3444 /// \endverbatim
ParseBlockLiteralExpression()3445 ExprResult Parser::ParseBlockLiteralExpression() {
3446   assert(Tok.is(tok::caret) && "block literal starts with ^");
3447   SourceLocation CaretLoc = ConsumeToken();
3448 
3449   PrettyStackTraceLoc CrashInfo(PP.getSourceManager(), CaretLoc,
3450                                 "block literal parsing");
3451 
3452   // Enter a scope to hold everything within the block.  This includes the
3453   // argument decls, decls within the compound expression, etc.  This also
3454   // allows determining whether a variable reference inside the block is
3455   // within or outside of the block.
3456   ParseScope BlockScope(this, Scope::BlockScope | Scope::FnScope |
3457                                   Scope::CompoundStmtScope | Scope::DeclScope);
3458 
3459   // Inform sema that we are starting a block.
3460   Actions.ActOnBlockStart(CaretLoc, getCurScope());
3461 
3462   // Parse the return type if present.
3463   DeclSpec DS(AttrFactory);
3464   Declarator ParamInfo(DS, DeclaratorContext::BlockLiteral);
3465   ParamInfo.setFunctionDefinitionKind(FunctionDefinitionKind::Definition);
3466   // FIXME: Since the return type isn't actually parsed, it can't be used to
3467   // fill ParamInfo with an initial valid range, so do it manually.
3468   ParamInfo.SetSourceRange(SourceRange(Tok.getLocation(), Tok.getLocation()));
3469 
3470   // If this block has arguments, parse them.  There is no ambiguity here with
3471   // the expression case, because the expression case requires a parameter list.
3472   if (Tok.is(tok::l_paren)) {
3473     ParseParenDeclarator(ParamInfo);
3474     // Parse the pieces after the identifier as if we had "int(...)".
3475     // SetIdentifier sets the source range end, but in this case we're past
3476     // that location.
3477     SourceLocation Tmp = ParamInfo.getSourceRange().getEnd();
3478     ParamInfo.SetIdentifier(nullptr, CaretLoc);
3479     ParamInfo.SetRangeEnd(Tmp);
3480     if (ParamInfo.isInvalidType()) {
3481       // If there was an error parsing the arguments, they may have
3482       // tried to use ^(x+y) which requires an argument list.  Just
3483       // skip the whole block literal.
3484       Actions.ActOnBlockError(CaretLoc, getCurScope());
3485       return ExprError();
3486     }
3487 
3488     MaybeParseGNUAttributes(ParamInfo);
3489 
3490     // Inform sema that we are starting a block.
3491     Actions.ActOnBlockArguments(CaretLoc, ParamInfo, getCurScope());
3492   } else if (!Tok.is(tok::l_brace)) {
3493     ParseBlockId(CaretLoc);
3494   } else {
3495     // Otherwise, pretend we saw (void).
3496     SourceLocation NoLoc;
3497     ParamInfo.AddTypeInfo(
3498         DeclaratorChunk::getFunction(/*HasProto=*/true,
3499                                      /*IsAmbiguous=*/false,
3500                                      /*RParenLoc=*/NoLoc,
3501                                      /*ArgInfo=*/nullptr,
3502                                      /*NumParams=*/0,
3503                                      /*EllipsisLoc=*/NoLoc,
3504                                      /*RParenLoc=*/NoLoc,
3505                                      /*RefQualifierIsLvalueRef=*/true,
3506                                      /*RefQualifierLoc=*/NoLoc,
3507                                      /*MutableLoc=*/NoLoc, EST_None,
3508                                      /*ESpecRange=*/SourceRange(),
3509                                      /*Exceptions=*/nullptr,
3510                                      /*ExceptionRanges=*/nullptr,
3511                                      /*NumExceptions=*/0,
3512                                      /*NoexceptExpr=*/nullptr,
3513                                      /*ExceptionSpecTokens=*/nullptr,
3514                                      /*DeclsInPrototype=*/None, CaretLoc,
3515                                      CaretLoc, ParamInfo),
3516         CaretLoc);
3517 
3518     MaybeParseGNUAttributes(ParamInfo);
3519 
3520     // Inform sema that we are starting a block.
3521     Actions.ActOnBlockArguments(CaretLoc, ParamInfo, getCurScope());
3522   }
3523 
3524 
3525   ExprResult Result(true);
3526   if (!Tok.is(tok::l_brace)) {
3527     // Saw something like: ^expr
3528     Diag(Tok, diag::err_expected_expression);
3529     Actions.ActOnBlockError(CaretLoc, getCurScope());
3530     return ExprError();
3531   }
3532 
3533   StmtResult Stmt(ParseCompoundStatementBody());
3534   BlockScope.Exit();
3535   if (!Stmt.isInvalid())
3536     Result = Actions.ActOnBlockStmtExpr(CaretLoc, Stmt.get(), getCurScope());
3537   else
3538     Actions.ActOnBlockError(CaretLoc, getCurScope());
3539   return Result;
3540 }
3541 
3542 /// ParseObjCBoolLiteral - This handles the objective-c Boolean literals.
3543 ///
3544 ///         '__objc_yes'
3545 ///         '__objc_no'
ParseObjCBoolLiteral()3546 ExprResult Parser::ParseObjCBoolLiteral() {
3547   tok::TokenKind Kind = Tok.getKind();
3548   return Actions.ActOnObjCBoolLiteral(ConsumeToken(), Kind);
3549 }
3550 
3551 /// Validate availability spec list, emitting diagnostics if necessary. Returns
3552 /// true if invalid.
CheckAvailabilitySpecList(Parser & P,ArrayRef<AvailabilitySpec> AvailSpecs)3553 static bool CheckAvailabilitySpecList(Parser &P,
3554                                       ArrayRef<AvailabilitySpec> AvailSpecs) {
3555   llvm::SmallSet<StringRef, 4> Platforms;
3556   bool HasOtherPlatformSpec = false;
3557   bool Valid = true;
3558   for (const auto &Spec : AvailSpecs) {
3559     if (Spec.isOtherPlatformSpec()) {
3560       if (HasOtherPlatformSpec) {
3561         P.Diag(Spec.getBeginLoc(), diag::err_availability_query_repeated_star);
3562         Valid = false;
3563       }
3564 
3565       HasOtherPlatformSpec = true;
3566       continue;
3567     }
3568 
3569     bool Inserted = Platforms.insert(Spec.getPlatform()).second;
3570     if (!Inserted) {
3571       // Rule out multiple version specs referring to the same platform.
3572       // For example, we emit an error for:
3573       // @available(macos 10.10, macos 10.11, *)
3574       StringRef Platform = Spec.getPlatform();
3575       P.Diag(Spec.getBeginLoc(), diag::err_availability_query_repeated_platform)
3576           << Spec.getEndLoc() << Platform;
3577       Valid = false;
3578     }
3579   }
3580 
3581   if (!HasOtherPlatformSpec) {
3582     SourceLocation InsertWildcardLoc = AvailSpecs.back().getEndLoc();
3583     P.Diag(InsertWildcardLoc, diag::err_availability_query_wildcard_required)
3584         << FixItHint::CreateInsertion(InsertWildcardLoc, ", *");
3585     return true;
3586   }
3587 
3588   return !Valid;
3589 }
3590 
3591 /// Parse availability query specification.
3592 ///
3593 ///  availability-spec:
3594 ///     '*'
3595 ///     identifier version-tuple
ParseAvailabilitySpec()3596 Optional<AvailabilitySpec> Parser::ParseAvailabilitySpec() {
3597   if (Tok.is(tok::star)) {
3598     return AvailabilitySpec(ConsumeToken());
3599   } else {
3600     // Parse the platform name.
3601     if (Tok.is(tok::code_completion)) {
3602       cutOffParsing();
3603       Actions.CodeCompleteAvailabilityPlatformName();
3604       return None;
3605     }
3606     if (Tok.isNot(tok::identifier)) {
3607       Diag(Tok, diag::err_avail_query_expected_platform_name);
3608       return None;
3609     }
3610 
3611     IdentifierLoc *PlatformIdentifier = ParseIdentifierLoc();
3612     SourceRange VersionRange;
3613     VersionTuple Version = ParseVersionTuple(VersionRange);
3614 
3615     if (Version.empty())
3616       return None;
3617 
3618     StringRef GivenPlatform = PlatformIdentifier->Ident->getName();
3619     StringRef Platform =
3620         AvailabilityAttr::canonicalizePlatformName(GivenPlatform);
3621 
3622     if (AvailabilityAttr::getPrettyPlatformName(Platform).empty()) {
3623       Diag(PlatformIdentifier->Loc,
3624            diag::err_avail_query_unrecognized_platform_name)
3625           << GivenPlatform;
3626       return None;
3627     }
3628 
3629     return AvailabilitySpec(Version, Platform, PlatformIdentifier->Loc,
3630                             VersionRange.getEnd());
3631   }
3632 }
3633 
ParseAvailabilityCheckExpr(SourceLocation BeginLoc)3634 ExprResult Parser::ParseAvailabilityCheckExpr(SourceLocation BeginLoc) {
3635   assert(Tok.is(tok::kw___builtin_available) ||
3636          Tok.isObjCAtKeyword(tok::objc_available));
3637 
3638   // Eat the available or __builtin_available.
3639   ConsumeToken();
3640 
3641   BalancedDelimiterTracker Parens(*this, tok::l_paren);
3642   if (Parens.expectAndConsume())
3643     return ExprError();
3644 
3645   SmallVector<AvailabilitySpec, 4> AvailSpecs;
3646   bool HasError = false;
3647   while (true) {
3648     Optional<AvailabilitySpec> Spec = ParseAvailabilitySpec();
3649     if (!Spec)
3650       HasError = true;
3651     else
3652       AvailSpecs.push_back(*Spec);
3653 
3654     if (!TryConsumeToken(tok::comma))
3655       break;
3656   }
3657 
3658   if (HasError) {
3659     SkipUntil(tok::r_paren, StopAtSemi);
3660     return ExprError();
3661   }
3662 
3663   CheckAvailabilitySpecList(*this, AvailSpecs);
3664 
3665   if (Parens.consumeClose())
3666     return ExprError();
3667 
3668   return Actions.ActOnObjCAvailabilityCheckExpr(AvailSpecs, BeginLoc,
3669                                                 Parens.getCloseLocation());
3670 }
3671