ParseExpr.cpp revision 281481daeb97e56bb19e394efc34bfd4ab85a226 
1//===--- ParseExpr.cpp - Expression Parsing -------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the Expression parsing implementation.  Expressions in
11// C99 basically consist of a bunch of binary operators with unary operators and
12// other random stuff at the leaves.
13//
14// In the C99 grammar, these unary operators bind tightest and are represented
15// as the 'cast-expression' production.  Everything else is either a binary
16// operator (e.g. '/') or a ternary operator ("?:").  The unary leaves are
17// handled by ParseCastExpression, the higher level pieces are handled by
18// ParseBinaryExpression.
19//
20//===----------------------------------------------------------------------===//
21
22#include "clang/Parse/Parser.h"
23#include "clang/Parse/DeclSpec.h"
24#include "clang/Parse/Scope.h"
25#include "ExtensionRAIIObject.h"
26#include "AstGuard.h"
27#include "llvm/ADT/SmallVector.h"
28#include "llvm/ADT/SmallString.h"
29using namespace clang;
30
31/// PrecedenceLevels - These are precedences for the binary/ternary operators in
32/// the C99 grammar.  These have been named to relate with the C99 grammar
33/// productions.  Low precedences numbers bind more weakly than high numbers.
34namespace prec {
35  enum Level {
36    Unknown        = 0,    // Not binary operator.
37    Comma          = 1,    // ,
38    Assignment     = 2,    // =, *=, /=, %=, +=, -=, <<=, >>=, &=, ^=, |=
39    Conditional    = 3,    // ?
40    LogicalOr      = 4,    // ||
41    LogicalAnd     = 5,    // &&
42    InclusiveOr    = 6,    // |
43    ExclusiveOr    = 7,    // ^
44    And            = 8,    // &
45    Equality       = 9,    // ==, !=
46    Relational     = 10,   //  >=, <=, >, <
47    Shift          = 11,   // <<, >>
48    Additive       = 12,   // -, +
49    Multiplicative = 13    // *, /, %
50  };
51}
52
53
54/// getBinOpPrecedence - Return the precedence of the specified binary operator
55/// token.  This returns:
56///
57static prec::Level getBinOpPrecedence(tok::TokenKind Kind) {
58  switch (Kind) {
59  default:                        return prec::Unknown;
60  case tok::comma:                return prec::Comma;
61  case tok::equal:
62  case tok::starequal:
63  case tok::slashequal:
64  case tok::percentequal:
65  case tok::plusequal:
66  case tok::minusequal:
67  case tok::lesslessequal:
68  case tok::greatergreaterequal:
69  case tok::ampequal:
70  case tok::caretequal:
71  case tok::pipeequal:            return prec::Assignment;
72  case tok::question:             return prec::Conditional;
73  case tok::pipepipe:             return prec::LogicalOr;
74  case tok::ampamp:               return prec::LogicalAnd;
75  case tok::pipe:                 return prec::InclusiveOr;
76  case tok::caret:                return prec::ExclusiveOr;
77  case tok::amp:                  return prec::And;
78  case tok::exclaimequal:
79  case tok::equalequal:           return prec::Equality;
80  case tok::lessequal:
81  case tok::less:
82  case tok::greaterequal:
83  case tok::greater:              return prec::Relational;
84  case tok::lessless:
85  case tok::greatergreater:       return prec::Shift;
86  case tok::plus:
87  case tok::minus:                return prec::Additive;
88  case tok::percent:
89  case tok::slash:
90  case tok::star:                 return prec::Multiplicative;
91  }
92}
93
94
95/// ParseExpression - Simple precedence-based parser for binary/ternary
96/// operators.
97///
98/// Note: we diverge from the C99 grammar when parsing the assignment-expression
99/// production.  C99 specifies that the LHS of an assignment operator should be
100/// parsed as a unary-expression, but consistency dictates that it be a
101/// conditional-expession.  In practice, the important thing here is that the
102/// LHS of an assignment has to be an l-value, which productions between
103/// unary-expression and conditional-expression don't produce.  Because we want
104/// consistency, we parse the LHS as a conditional-expression, then check for
105/// l-value-ness in semantic analysis stages.
106///
107///       multiplicative-expression: [C99 6.5.5]
108///         cast-expression
109///         multiplicative-expression '*' cast-expression
110///         multiplicative-expression '/' cast-expression
111///         multiplicative-expression '%' cast-expression
112///
113///       additive-expression: [C99 6.5.6]
114///         multiplicative-expression
115///         additive-expression '+' multiplicative-expression
116///         additive-expression '-' multiplicative-expression
117///
118///       shift-expression: [C99 6.5.7]
119///         additive-expression
120///         shift-expression '<<' additive-expression
121///         shift-expression '>>' additive-expression
122///
123///       relational-expression: [C99 6.5.8]
124///         shift-expression
125///         relational-expression '<' shift-expression
126///         relational-expression '>' shift-expression
127///         relational-expression '<=' shift-expression
128///         relational-expression '>=' shift-expression
129///
130///       equality-expression: [C99 6.5.9]
131///         relational-expression
132///         equality-expression '==' relational-expression
133///         equality-expression '!=' relational-expression
134///
135///       AND-expression: [C99 6.5.10]
136///         equality-expression
137///         AND-expression '&' equality-expression
138///
139///       exclusive-OR-expression: [C99 6.5.11]
140///         AND-expression
141///         exclusive-OR-expression '^' AND-expression
142///
143///       inclusive-OR-expression: [C99 6.5.12]
144///         exclusive-OR-expression
145///         inclusive-OR-expression '|' exclusive-OR-expression
146///
147///       logical-AND-expression: [C99 6.5.13]
148///         inclusive-OR-expression
149///         logical-AND-expression '&&' inclusive-OR-expression
150///
151///       logical-OR-expression: [C99 6.5.14]
152///         logical-AND-expression
153///         logical-OR-expression '||' logical-AND-expression
154///
155///       conditional-expression: [C99 6.5.15]
156///         logical-OR-expression
157///         logical-OR-expression '?' expression ':' conditional-expression
158/// [GNU]   logical-OR-expression '?' ':' conditional-expression
159///
160///       assignment-expression: [C99 6.5.16]
161///         conditional-expression
162///         unary-expression assignment-operator assignment-expression
163/// [C++]   throw-expression [C++ 15]
164///
165///       assignment-operator: one of
166///         = *= /= %= += -= <<= >>= &= ^= |=
167///
168///       expression: [C99 6.5.17]
169///         assignment-expression
170///         expression ',' assignment-expression
171///
172Parser::OwningExprResult Parser::ParseExpression() {
173  if (Tok.is(tok::kw_throw))
174    return ParseThrowExpression();
175
176  OwningExprResult LHS(ParseCastExpression(false));
177  if (LHS.isInvalid()) return move(LHS);
178
179  return ParseRHSOfBinaryExpression(move(LHS), prec::Comma);
180}
181
182/// This routine is called when the '@' is seen and consumed.
183/// Current token is an Identifier and is not a 'try'. This
184/// routine is necessary to disambiguate @try-statement from,
185/// for example, @encode-expression.
186///
187Parser::OwningExprResult
188Parser::ParseExpressionWithLeadingAt(SourceLocation AtLoc) {
189  OwningExprResult LHS(ParseObjCAtExpression(AtLoc));
190  if (LHS.isInvalid()) return move(LHS);
191
192  return ParseRHSOfBinaryExpression(move(LHS), prec::Comma);
193}
194
195/// This routine is called when a leading '__extension__' is seen and
196/// consumed.  This is necessary because the token gets consumed in the
197/// process of disambiguating between an expression and a declaration.
198Parser::OwningExprResult
199Parser::ParseExpressionWithLeadingExtension(SourceLocation ExtLoc) {
200  // FIXME: The handling for throw is almost certainly wrong.
201  if (Tok.is(tok::kw_throw))
202    return ParseThrowExpression();
203
204  OwningExprResult LHS(ParseCastExpression(false));
205  if (LHS.isInvalid()) return move(LHS);
206
207  LHS = Actions.ActOnUnaryOp(CurScope, ExtLoc, tok::kw___extension__,
208                             move_arg(LHS));
209  if (LHS.isInvalid()) return move(LHS);
210
211  return ParseRHSOfBinaryExpression(move(LHS), prec::Comma);
212}
213
214/// ParseAssignmentExpression - Parse an expr that doesn't include commas.
215///
216Parser::OwningExprResult Parser::ParseAssignmentExpression() {
217  if (Tok.is(tok::kw_throw))
218    return ParseThrowExpression();
219
220  OwningExprResult LHS(ParseCastExpression(false));
221  if (LHS.isInvalid()) return move(LHS);
222
223  return ParseRHSOfBinaryExpression(move(LHS), prec::Assignment);
224}
225
226/// ParseAssignmentExprWithObjCMessageExprStart - Parse an assignment expression
227/// where part of an objc message send has already been parsed.  In this case
228/// LBracLoc indicates the location of the '[' of the message send, and either
229/// ReceiverName or ReceiverExpr is non-null indicating the receiver of the
230/// message.
231///
232/// Since this handles full assignment-expression's, it handles postfix
233/// expressions and other binary operators for these expressions as well.
234Parser::OwningExprResult
235Parser::ParseAssignmentExprWithObjCMessageExprStart(SourceLocation LBracLoc,
236                                                    SourceLocation NameLoc,
237                                                   IdentifierInfo *ReceiverName,
238                                                    ExprArg ReceiverExpr) {
239  OwningExprResult R(ParseObjCMessageExpressionBody(LBracLoc, NameLoc,
240                                                    ReceiverName,
241                                                    move(ReceiverExpr)));
242  if (R.isInvalid()) return move(R);
243  R = ParsePostfixExpressionSuffix(move(R));
244  if (R.isInvalid()) return move(R);
245  return ParseRHSOfBinaryExpression(move(R), prec::Assignment);
246}
247
248
249Parser::OwningExprResult Parser::ParseConstantExpression() {
250  OwningExprResult LHS(ParseCastExpression(false));
251  if (LHS.isInvalid()) return move(LHS);
252
253  return ParseRHSOfBinaryExpression(move(LHS), prec::Conditional);
254}
255
256/// ParseRHSOfBinaryExpression - Parse a binary expression that starts with
257/// LHS and has a precedence of at least MinPrec.
258Parser::OwningExprResult
259Parser::ParseRHSOfBinaryExpression(OwningExprResult LHS, unsigned MinPrec) {
260  unsigned NextTokPrec = getBinOpPrecedence(Tok.getKind());
261  SourceLocation ColonLoc;
262
263  while (1) {
264    // If this token has a lower precedence than we are allowed to parse (e.g.
265    // because we are called recursively, or because the token is not a binop),
266    // then we are done!
267    if (NextTokPrec < MinPrec)
268      return move(LHS);
269
270    // Consume the operator, saving the operator token for error reporting.
271    Token OpToken = Tok;
272    ConsumeToken();
273
274    // Special case handling for the ternary operator.
275    OwningExprResult TernaryMiddle(Actions, true);
276    if (NextTokPrec == prec::Conditional) {
277      if (Tok.isNot(tok::colon)) {
278        // Handle this production specially:
279        //   logical-OR-expression '?' expression ':' conditional-expression
280        // In particular, the RHS of the '?' is 'expression', not
281        // 'logical-OR-expression' as we might expect.
282        TernaryMiddle = ParseExpression();
283        if (TernaryMiddle.isInvalid())
284          return move(TernaryMiddle);
285      } else {
286        // Special case handling of "X ? Y : Z" where Y is empty:
287        //   logical-OR-expression '?' ':' conditional-expression   [GNU]
288        TernaryMiddle = 0;
289        Diag(Tok, diag::ext_gnu_conditional_expr);
290      }
291
292      if (Tok.isNot(tok::colon)) {
293        Diag(Tok, diag::err_expected_colon);
294        Diag(OpToken, diag::note_matching) << "?";
295        return ExprError();
296      }
297
298      // Eat the colon.
299      ColonLoc = ConsumeToken();
300    }
301
302    // Parse another leaf here for the RHS of the operator.
303    OwningExprResult RHS(ParseCastExpression(false));
304    if (RHS.isInvalid())
305      return move(RHS);
306
307    // Remember the precedence of this operator and get the precedence of the
308    // operator immediately to the right of the RHS.
309    unsigned ThisPrec = NextTokPrec;
310    NextTokPrec = getBinOpPrecedence(Tok.getKind());
311
312    // Assignment and conditional expressions are right-associative.
313    bool isRightAssoc = ThisPrec == prec::Conditional ||
314                        ThisPrec == prec::Assignment;
315
316    // Get the precedence of the operator to the right of the RHS.  If it binds
317    // more tightly with RHS than we do, evaluate it completely first.
318    if (ThisPrec < NextTokPrec ||
319        (ThisPrec == NextTokPrec && isRightAssoc)) {
320      // If this is left-associative, only parse things on the RHS that bind
321      // more tightly than the current operator.  If it is left-associative, it
322      // is okay, to bind exactly as tightly.  For example, compile A=B=C=D as
323      // A=(B=(C=D)), where each paren is a level of recursion here.
324      // The function takes ownership of the RHS.
325      RHS = ParseRHSOfBinaryExpression(move(RHS), ThisPrec + !isRightAssoc);
326      if (RHS.isInvalid())
327        return move(RHS);
328
329      NextTokPrec = getBinOpPrecedence(Tok.getKind());
330    }
331    assert(NextTokPrec <= ThisPrec && "Recursion didn't work!");
332
333    if (!LHS.isInvalid()) {
334      // Combine the LHS and RHS into the LHS (e.g. build AST).
335      if (TernaryMiddle.isInvalid())
336        LHS = Actions.ActOnBinOp(CurScope, OpToken.getLocation(),
337                                 OpToken.getKind(), move_arg(LHS),
338                                 move_arg(RHS));
339      else
340        LHS = Actions.ActOnConditionalOp(OpToken.getLocation(), ColonLoc,
341                                         move_arg(LHS), move_arg(TernaryMiddle),
342                                         move_arg(RHS));
343    }
344  }
345}
346
347/// ParseCastExpression - Parse a cast-expression, or, if isUnaryExpression is
348/// true, parse a unary-expression.
349///
350///       cast-expression: [C99 6.5.4]
351///         unary-expression
352///         '(' type-name ')' cast-expression
353///
354///       unary-expression:  [C99 6.5.3]
355///         postfix-expression
356///         '++' unary-expression
357///         '--' unary-expression
358///         unary-operator cast-expression
359///         'sizeof' unary-expression
360///         'sizeof' '(' type-name ')'
361/// [GNU]   '__alignof' unary-expression
362/// [GNU]   '__alignof' '(' type-name ')'
363/// [C++0x] 'alignof' '(' type-id ')'
364/// [GNU]   '&&' identifier
365/// [C++]   new-expression
366/// [C++]   delete-expression
367///
368///       unary-operator: one of
369///         '&'  '*'  '+'  '-'  '~'  '!'
370/// [GNU]   '__extension__'  '__real'  '__imag'
371///
372///       primary-expression: [C99 6.5.1]
373/// [C99]   identifier
374/// [C++]   id-expression
375///         constant
376///         string-literal
377/// [C++]   boolean-literal  [C++ 2.13.5]
378///         '(' expression ')'
379///         '__func__'        [C99 6.4.2.2]
380/// [GNU]   '__FUNCTION__'
381/// [GNU]   '__PRETTY_FUNCTION__'
382/// [GNU]   '(' compound-statement ')'
383/// [GNU]   '__builtin_va_arg' '(' assignment-expression ',' type-name ')'
384/// [GNU]   '__builtin_offsetof' '(' type-name ',' offsetof-member-designator')'
385/// [GNU]   '__builtin_choose_expr' '(' assign-expr ',' assign-expr ','
386///                                     assign-expr ')'
387/// [GNU]   '__builtin_types_compatible_p' '(' type-name ',' type-name ')'
388/// [GNU]   '__null'
389/// [OBJC]  '[' objc-message-expr ']'
390/// [OBJC]  '@selector' '(' objc-selector-arg ')'
391/// [OBJC]  '@protocol' '(' identifier ')'
392/// [OBJC]  '@encode' '(' type-name ')'
393/// [OBJC]  objc-string-literal
394/// [C++]   simple-type-specifier '(' expression-list[opt] ')'      [C++ 5.2.3]
395/// [C++]   typename-specifier '(' expression-list[opt] ')'         [TODO]
396/// [C++]   'const_cast' '<' type-name '>' '(' expression ')'       [C++ 5.2p1]
397/// [C++]   'dynamic_cast' '<' type-name '>' '(' expression ')'     [C++ 5.2p1]
398/// [C++]   'reinterpret_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
399/// [C++]   'static_cast' '<' type-name '>' '(' expression ')'      [C++ 5.2p1]
400/// [C++]   'typeid' '(' expression ')'                             [C++ 5.2p1]
401/// [C++]   'typeid' '(' type-id ')'                                [C++ 5.2p1]
402/// [C++]   'this'          [C++ 9.3.2]
403/// [G++]   unary-type-trait '(' type-id ')'
404/// [G++]   binary-type-trait '(' type-id ',' type-id ')'           [TODO]
405/// [clang] '^' block-literal
406///
407///       constant: [C99 6.4.4]
408///         integer-constant
409///         floating-constant
410///         enumeration-constant -> identifier
411///         character-constant
412///
413///       id-expression: [C++ 5.1]
414///                   unqualified-id
415///                   qualified-id           [TODO]
416///
417///       unqualified-id: [C++ 5.1]
418///                   identifier
419///                   operator-function-id
420///                   conversion-function-id [TODO]
421///                   '~' class-name         [TODO]
422///                   template-id            [TODO]
423///
424///       new-expression: [C++ 5.3.4]
425///                   '::'[opt] 'new' new-placement[opt] new-type-id
426///                                     new-initializer[opt]
427///                   '::'[opt] 'new' new-placement[opt] '(' type-id ')'
428///                                     new-initializer[opt]
429///
430///       delete-expression: [C++ 5.3.5]
431///                   '::'[opt] 'delete' cast-expression
432///                   '::'[opt] 'delete' '[' ']' cast-expression
433///
434/// [GNU] unary-type-trait:
435///                   '__has_nothrow_assign'                  [TODO]
436///                   '__has_nothrow_copy'                    [TODO]
437///                   '__has_nothrow_constructor'             [TODO]
438///                   '__has_trivial_assign'                  [TODO]
439///                   '__has_trivial_copy'                    [TODO]
440///                   '__has_trivial_constructor'             [TODO]
441///                   '__has_trivial_destructor'              [TODO]
442///                   '__has_virtual_destructor'              [TODO]
443///                   '__is_abstract'                         [TODO]
444///                   '__is_class'
445///                   '__is_empty'                            [TODO]
446///                   '__is_enum'
447///                   '__is_pod'
448///                   '__is_polymorphic'
449///                   '__is_union'
450///
451/// [GNU] binary-type-trait:
452///                   '__is_base_of'                          [TODO]
453///
454Parser::OwningExprResult Parser::ParseCastExpression(bool isUnaryExpression) {
455  OwningExprResult Res(Actions);
456  tok::TokenKind SavedKind = Tok.getKind();
457
458  // This handles all of cast-expression, unary-expression, postfix-expression,
459  // and primary-expression.  We handle them together like this for efficiency
460  // and to simplify handling of an expression starting with a '(' token: which
461  // may be one of a parenthesized expression, cast-expression, compound literal
462  // expression, or statement expression.
463  //
464  // If the parsed tokens consist of a primary-expression, the cases below
465  // call ParsePostfixExpressionSuffix to handle the postfix expression
466  // suffixes.  Cases that cannot be followed by postfix exprs should
467  // return without invoking ParsePostfixExpressionSuffix.
468  switch (SavedKind) {
469  case tok::l_paren: {
470    // If this expression is limited to being a unary-expression, the parent can
471    // not start a cast expression.
472    ParenParseOption ParenExprType =
473      isUnaryExpression ? CompoundLiteral : CastExpr;
474    TypeTy *CastTy;
475    SourceLocation LParenLoc = Tok.getLocation();
476    SourceLocation RParenLoc;
477    Res = ParseParenExpression(ParenExprType, CastTy, RParenLoc);
478    if (Res.isInvalid()) return move(Res);
479
480    switch (ParenExprType) {
481    case SimpleExpr:   break;    // Nothing else to do.
482    case CompoundStmt: break;  // Nothing else to do.
483    case CompoundLiteral:
484      // We parsed '(' type-name ')' '{' ... '}'.  If any suffixes of
485      // postfix-expression exist, parse them now.
486      break;
487    case CastExpr:
488      // We parsed '(' type-name ')' and the thing after it wasn't a '{'.  Parse
489      // the cast-expression that follows it next.
490      // TODO: For cast expression with CastTy.
491      Res = ParseCastExpression(false);
492      if (!Res.isInvalid())
493        Res = Actions.ActOnCastExpr(LParenLoc, CastTy, RParenLoc,
494                                    move_arg(Res));
495      return move(Res);
496    }
497
498    // These can be followed by postfix-expr pieces.
499    return ParsePostfixExpressionSuffix(move(Res));
500  }
501
502    // primary-expression
503  case tok::numeric_constant:
504    // constant: integer-constant
505    // constant: floating-constant
506
507    Res = Actions.ActOnNumericConstant(Tok);
508    ConsumeToken();
509
510    // These can be followed by postfix-expr pieces.
511    return ParsePostfixExpressionSuffix(move(Res));
512
513  case tok::kw_true:
514  case tok::kw_false:
515    return ParseCXXBoolLiteral();
516
517  case tok::identifier: {      // primary-expression: identifier
518                               // unqualified-id: identifier
519                               // constant: enumeration-constant
520    // Turn a potentially qualified name into a annot_typename or
521    // annot_cxxscope if it would be valid.  This handles things like x::y, etc.
522    if (getLang().CPlusPlus) {
523      // If TryAnnotateTypeOrScopeToken annotates the token, tail recurse.
524      if (TryAnnotateTypeOrScopeToken())
525        return ParseCastExpression(isUnaryExpression);
526    }
527
528    // Consume the identifier so that we can see if it is followed by a '('.
529    // Function designators are allowed to be undeclared (C99 6.5.1p2), so we
530    // need to know whether or not this identifier is a function designator or
531    // not.
532    IdentifierInfo &II = *Tok.getIdentifierInfo();
533    SourceLocation L = ConsumeToken();
534    Res = Actions.ActOnIdentifierExpr(CurScope, L, II, Tok.is(tok::l_paren));
535    // These can be followed by postfix-expr pieces.
536    return ParsePostfixExpressionSuffix(move(Res));
537  }
538  case tok::char_constant:     // constant: character-constant
539    Res = Actions.ActOnCharacterConstant(Tok);
540    ConsumeToken();
541    // These can be followed by postfix-expr pieces.
542    return ParsePostfixExpressionSuffix(move(Res));
543  case tok::kw___func__:       // primary-expression: __func__ [C99 6.4.2.2]
544  case tok::kw___FUNCTION__:   // primary-expression: __FUNCTION__ [GNU]
545  case tok::kw___PRETTY_FUNCTION__:  // primary-expression: __P..Y_F..N__ [GNU]
546    Res = Actions.ActOnPredefinedExpr(Tok.getLocation(), SavedKind);
547    ConsumeToken();
548    // These can be followed by postfix-expr pieces.
549    return ParsePostfixExpressionSuffix(move(Res));
550  case tok::string_literal:    // primary-expression: string-literal
551  case tok::wide_string_literal:
552    Res = ParseStringLiteralExpression();
553    if (Res.isInvalid()) return move(Res);
554    // This can be followed by postfix-expr pieces (e.g. "foo"[1]).
555    return ParsePostfixExpressionSuffix(move(Res));
556  case tok::kw___builtin_va_arg:
557  case tok::kw___builtin_offsetof:
558  case tok::kw___builtin_choose_expr:
559  case tok::kw___builtin_overload:
560  case tok::kw___builtin_types_compatible_p:
561    return ParseBuiltinPrimaryExpression();
562  case tok::kw___null:
563    return Owned(Actions.ActOnGNUNullExpr(ConsumeToken()));
564    break;
565  case tok::plusplus:      // unary-expression: '++' unary-expression
566  case tok::minusminus: {  // unary-expression: '--' unary-expression
567    SourceLocation SavedLoc = ConsumeToken();
568    Res = ParseCastExpression(true);
569    if (!Res.isInvalid())
570      Res = Actions.ActOnUnaryOp(CurScope, SavedLoc, SavedKind, move_arg(Res));
571    return move(Res);
572  }
573  case tok::amp:           // unary-expression: '&' cast-expression
574  case tok::star:          // unary-expression: '*' cast-expression
575  case tok::plus:          // unary-expression: '+' cast-expression
576  case tok::minus:         // unary-expression: '-' cast-expression
577  case tok::tilde:         // unary-expression: '~' cast-expression
578  case tok::exclaim:       // unary-expression: '!' cast-expression
579  case tok::kw___real:     // unary-expression: '__real' cast-expression [GNU]
580  case tok::kw___imag: {   // unary-expression: '__imag' cast-expression [GNU]
581    SourceLocation SavedLoc = ConsumeToken();
582    Res = ParseCastExpression(false);
583    if (!Res.isInvalid())
584      Res = Actions.ActOnUnaryOp(CurScope, SavedLoc, SavedKind, move_arg(Res));
585    return move(Res);
586  }
587
588  case tok::kw___extension__:{//unary-expression:'__extension__' cast-expr [GNU]
589    // __extension__ silences extension warnings in the subexpression.
590    ExtensionRAIIObject O(Diags);  // Use RAII to do this.
591    SourceLocation SavedLoc = ConsumeToken();
592    Res = ParseCastExpression(false);
593    if (!Res.isInvalid())
594      Res = Actions.ActOnUnaryOp(CurScope, SavedLoc, SavedKind, move_arg(Res));
595    return move(Res);
596  }
597  case tok::kw_sizeof:     // unary-expression: 'sizeof' unary-expression
598                           // unary-expression: 'sizeof' '(' type-name ')'
599  case tok::kw_alignof:
600  case tok::kw___alignof:  // unary-expression: '__alignof' unary-expression
601                           // unary-expression: '__alignof' '(' type-name ')'
602                           // unary-expression: 'alignof' '(' type-id ')'
603    return ParseSizeofAlignofExpression();
604  case tok::ampamp: {      // unary-expression: '&&' identifier
605    SourceLocation AmpAmpLoc = ConsumeToken();
606    if (Tok.isNot(tok::identifier))
607      return ExprError(Diag(Tok, diag::err_expected_ident));
608
609    Diag(AmpAmpLoc, diag::ext_gnu_address_of_label);
610    Res = Actions.ActOnAddrLabel(AmpAmpLoc, Tok.getLocation(),
611                                 Tok.getIdentifierInfo());
612    ConsumeToken();
613    return move(Res);
614  }
615  case tok::kw_const_cast:
616  case tok::kw_dynamic_cast:
617  case tok::kw_reinterpret_cast:
618  case tok::kw_static_cast:
619    Res = ParseCXXCasts();
620    // These can be followed by postfix-expr pieces.
621    return ParsePostfixExpressionSuffix(move(Res));
622  case tok::kw_typeid:
623    Res = ParseCXXTypeid();
624    // This can be followed by postfix-expr pieces.
625    return ParsePostfixExpressionSuffix(move(Res));
626  case tok::kw_this:
627    Res = ParseCXXThis();
628    // This can be followed by postfix-expr pieces.
629    return ParsePostfixExpressionSuffix(move(Res));
630
631  case tok::kw_char:
632  case tok::kw_wchar_t:
633  case tok::kw_bool:
634  case tok::kw_short:
635  case tok::kw_int:
636  case tok::kw_long:
637  case tok::kw_signed:
638  case tok::kw_unsigned:
639  case tok::kw_float:
640  case tok::kw_double:
641  case tok::kw_void:
642  case tok::kw_typeof:
643  case tok::annot_typename: {
644    if (!getLang().CPlusPlus) {
645      Diag(Tok, diag::err_expected_expression);
646      return ExprError();
647    }
648
649    // postfix-expression: simple-type-specifier '(' expression-list[opt] ')'
650    //
651    DeclSpec DS;
652    ParseCXXSimpleTypeSpecifier(DS);
653    if (Tok.isNot(tok::l_paren))
654      return ExprError(Diag(Tok, diag::err_expected_lparen_after_type)
655                         << DS.getSourceRange());
656
657    Res = ParseCXXTypeConstructExpression(DS);
658    // This can be followed by postfix-expr pieces.
659    return ParsePostfixExpressionSuffix(move(Res));
660  }
661
662  case tok::annot_cxxscope: // [C++] id-expression: qualified-id
663  case tok::kw_operator: // [C++] id-expression: operator/conversion-function-id
664                         //                      template-id
665    Res = ParseCXXIdExpression();
666    return ParsePostfixExpressionSuffix(move(Res));
667
668  case tok::coloncolon: {
669    // ::foo::bar -> global qualified name etc.   If TryAnnotateTypeOrScopeToken
670    // annotates the token, tail recurse.
671    if (TryAnnotateTypeOrScopeToken())
672      return ParseCastExpression(isUnaryExpression);
673
674    // ::new -> [C++] new-expression
675    // ::delete -> [C++] delete-expression
676    SourceLocation CCLoc = ConsumeToken();
677    if (Tok.is(tok::kw_new))
678      return ParseCXXNewExpression(true, CCLoc);
679    if (Tok.is(tok::kw_delete))
680      return ParseCXXDeleteExpression(true, CCLoc);
681
682    // This is not a type name or scope specifier, it is an invalid expression.
683    Diag(CCLoc, diag::err_expected_expression);
684    return ExprError();
685  }
686
687  case tok::kw_new: // [C++] new-expression
688    return ParseCXXNewExpression(false, Tok.getLocation());
689
690  case tok::kw_delete: // [C++] delete-expression
691    return ParseCXXDeleteExpression(false, Tok.getLocation());
692
693  case tok::kw___is_pod: // [GNU] unary-type-trait
694  case tok::kw___is_class:
695  case tok::kw___is_enum:
696  case tok::kw___is_union:
697  case tok::kw___is_polymorphic:
698    return ParseUnaryTypeTrait();
699
700  case tok::at: {
701    SourceLocation AtLoc = ConsumeToken();
702    return ParseObjCAtExpression(AtLoc);
703  }
704  case tok::caret:
705    if (getLang().Blocks)
706      return ParsePostfixExpressionSuffix(ParseBlockLiteralExpression());
707    Diag(Tok, diag::err_expected_expression);
708    return ExprError();
709  case tok::l_square:
710    // These can be followed by postfix-expr pieces.
711    if (getLang().ObjC1)
712      return ParsePostfixExpressionSuffix(ParseObjCMessageExpression());
713    // FALL THROUGH.
714  default:
715    Diag(Tok, diag::err_expected_expression);
716    return ExprError();
717  }
718
719  // unreachable.
720  abort();
721}
722
723/// ParsePostfixExpressionSuffix - Once the leading part of a postfix-expression
724/// is parsed, this method parses any suffixes that apply.
725///
726///       postfix-expression: [C99 6.5.2]
727///         primary-expression
728///         postfix-expression '[' expression ']'
729///         postfix-expression '(' argument-expression-list[opt] ')'
730///         postfix-expression '.' identifier
731///         postfix-expression '->' identifier
732///         postfix-expression '++'
733///         postfix-expression '--'
734///         '(' type-name ')' '{' initializer-list '}'
735///         '(' type-name ')' '{' initializer-list ',' '}'
736///
737///       argument-expression-list: [C99 6.5.2]
738///         argument-expression
739///         argument-expression-list ',' assignment-expression
740///
741Parser::OwningExprResult
742Parser::ParsePostfixExpressionSuffix(OwningExprResult LHS) {
743  // Now that the primary-expression piece of the postfix-expression has been
744  // parsed, see if there are any postfix-expression pieces here.
745  SourceLocation Loc;
746  while (1) {
747    switch (Tok.getKind()) {
748    default:  // Not a postfix-expression suffix.
749      return move(LHS);
750    case tok::l_square: {  // postfix-expression: p-e '[' expression ']'
751      Loc = ConsumeBracket();
752      OwningExprResult Idx(ParseExpression());
753
754      SourceLocation RLoc = Tok.getLocation();
755
756      if (!LHS.isInvalid() && !Idx.isInvalid() && Tok.is(tok::r_square)) {
757        LHS = Actions.ActOnArraySubscriptExpr(CurScope, move_arg(LHS), Loc,
758                                              move_arg(Idx), RLoc);
759      } else
760        LHS = ExprError();
761
762      // Match the ']'.
763      MatchRHSPunctuation(tok::r_square, Loc);
764      break;
765    }
766
767    case tok::l_paren: {   // p-e: p-e '(' argument-expression-list[opt] ')'
768      ExprVector ArgExprs(Actions);
769      CommaLocsTy CommaLocs;
770
771      Loc = ConsumeParen();
772
773      if (Tok.isNot(tok::r_paren)) {
774        if (ParseExpressionList(ArgExprs, CommaLocs)) {
775          SkipUntil(tok::r_paren);
776          return ExprError();
777        }
778      }
779
780      // Match the ')'.
781      if (!LHS.isInvalid() && Tok.is(tok::r_paren)) {
782        assert((ArgExprs.size() == 0 || ArgExprs.size()-1 == CommaLocs.size())&&
783               "Unexpected number of commas!");
784        LHS = Actions.ActOnCallExpr(CurScope, move_arg(LHS), Loc,
785                                    move_arg(ArgExprs), &CommaLocs[0],
786                                    Tok.getLocation());
787      }
788
789      MatchRHSPunctuation(tok::r_paren, Loc);
790      break;
791    }
792    case tok::arrow:       // postfix-expression: p-e '->' identifier
793    case tok::period: {    // postfix-expression: p-e '.' identifier
794      tok::TokenKind OpKind = Tok.getKind();
795      SourceLocation OpLoc = ConsumeToken();  // Eat the "." or "->" token.
796
797      if (Tok.isNot(tok::identifier)) {
798        Diag(Tok, diag::err_expected_ident);
799        return ExprError();
800      }
801
802      if (!LHS.isInvalid()) {
803        LHS = Actions.ActOnMemberReferenceExpr(CurScope, move_arg(LHS), OpLoc,
804                                               OpKind, Tok.getLocation(),
805                                               *Tok.getIdentifierInfo());
806      }
807      ConsumeToken();
808      break;
809    }
810    case tok::plusplus:    // postfix-expression: postfix-expression '++'
811    case tok::minusminus:  // postfix-expression: postfix-expression '--'
812      if (!LHS.isInvalid()) {
813        LHS = Actions.ActOnPostfixUnaryOp(CurScope, Tok.getLocation(),
814                                          Tok.getKind(), move_arg(LHS));
815      }
816      ConsumeToken();
817      break;
818    }
819  }
820}
821
822
823/// ParseSizeofAlignofExpression - Parse a sizeof or alignof expression.
824///       unary-expression:  [C99 6.5.3]
825///         'sizeof' unary-expression
826///         'sizeof' '(' type-name ')'
827/// [GNU]   '__alignof' unary-expression
828/// [GNU]   '__alignof' '(' type-name ')'
829/// [C++0x] 'alignof' '(' type-id ')'
830Parser::OwningExprResult Parser::ParseSizeofAlignofExpression() {
831  assert((Tok.is(tok::kw_sizeof) || Tok.is(tok::kw___alignof)
832          || Tok.is(tok::kw_alignof)) &&
833         "Not a sizeof/alignof expression!");
834  Token OpTok = Tok;
835  ConsumeToken();
836
837  // If the operand doesn't start with an '(', it must be an expression.
838  OwningExprResult Operand(Actions);
839  if (Tok.isNot(tok::l_paren)) {
840    Operand = ParseCastExpression(true);
841  } else {
842    // If it starts with a '(', we know that it is either a parenthesized
843    // type-name, or it is a unary-expression that starts with a compound
844    // literal, or starts with a primary-expression that is a parenthesized
845    // expression.
846    ParenParseOption ExprType = CastExpr;
847    TypeTy *CastTy;
848    SourceLocation LParenLoc = Tok.getLocation(), RParenLoc;
849    Operand = ParseParenExpression(ExprType, CastTy, RParenLoc);
850
851    // If ParseParenExpression parsed a '(typename)' sequence only, the this is
852    // sizeof/alignof a type.  Otherwise, it is sizeof/alignof an expression.
853    if (ExprType == CastExpr)
854      return Actions.ActOnSizeOfAlignOfExpr(OpTok.getLocation(),
855                                            OpTok.is(tok::kw_sizeof),
856                                            /*isType=*/true, CastTy,
857                                            SourceRange(LParenLoc, RParenLoc));
858
859    // If this is a parenthesized expression, it is the start of a
860    // unary-expression, but doesn't include any postfix pieces.  Parse these
861    // now if present.
862    Operand = ParsePostfixExpressionSuffix(move(Operand));
863  }
864
865  // If we get here, the operand to the sizeof/alignof was an expresion.
866  if (!Operand.isInvalid())
867    Operand = Actions.ActOnSizeOfAlignOfExpr(OpTok.getLocation(),
868                                             OpTok.is(tok::kw_sizeof),
869                                             /*isType=*/false,
870                                             Operand.release(), SourceRange());
871  return move(Operand);
872}
873
874/// ParseBuiltinPrimaryExpression
875///
876///       primary-expression: [C99 6.5.1]
877/// [GNU]   '__builtin_va_arg' '(' assignment-expression ',' type-name ')'
878/// [GNU]   '__builtin_offsetof' '(' type-name ',' offsetof-member-designator')'
879/// [GNU]   '__builtin_choose_expr' '(' assign-expr ',' assign-expr ','
880///                                     assign-expr ')'
881/// [GNU]   '__builtin_types_compatible_p' '(' type-name ',' type-name ')'
882/// [CLANG] '__builtin_overload' '(' expr (',' expr)* ')'
883///
884/// [GNU] offsetof-member-designator:
885/// [GNU]   identifier
886/// [GNU]   offsetof-member-designator '.' identifier
887/// [GNU]   offsetof-member-designator '[' expression ']'
888///
889Parser::OwningExprResult Parser::ParseBuiltinPrimaryExpression() {
890  OwningExprResult Res(Actions);
891  const IdentifierInfo *BuiltinII = Tok.getIdentifierInfo();
892
893  tok::TokenKind T = Tok.getKind();
894  SourceLocation StartLoc = ConsumeToken();   // Eat the builtin identifier.
895
896  // All of these start with an open paren.
897  if (Tok.isNot(tok::l_paren))
898    return ExprError(Diag(Tok, diag::err_expected_lparen_after_id)
899                       << BuiltinII);
900
901  SourceLocation LParenLoc = ConsumeParen();
902  // TODO: Build AST.
903
904  switch (T) {
905  default: assert(0 && "Not a builtin primary expression!");
906  case tok::kw___builtin_va_arg: {
907    OwningExprResult Expr(ParseAssignmentExpression());
908    if (Expr.isInvalid()) {
909      SkipUntil(tok::r_paren);
910      return ExprError();
911    }
912
913    if (ExpectAndConsume(tok::comma, diag::err_expected_comma, "",tok::r_paren))
914      return ExprError();
915
916    TypeTy *Ty = ParseTypeName();
917
918    if (Tok.isNot(tok::r_paren)) {
919      Diag(Tok, diag::err_expected_rparen);
920      return ExprError();
921    }
922    Res = Actions.ActOnVAArg(StartLoc, Expr.release(), Ty, ConsumeParen());
923    break;
924  }
925  case tok::kw___builtin_offsetof: {
926    SourceLocation TypeLoc = Tok.getLocation();
927    TypeTy *Ty = ParseTypeName();
928
929    if (ExpectAndConsume(tok::comma, diag::err_expected_comma, "",tok::r_paren))
930      return ExprError();
931
932    // We must have at least one identifier here.
933    if (Tok.isNot(tok::identifier)) {
934      Diag(Tok, diag::err_expected_ident);
935      SkipUntil(tok::r_paren);
936      return ExprError();
937    }
938
939    // Keep track of the various subcomponents we see.
940    llvm::SmallVector<Action::OffsetOfComponent, 4> Comps;
941
942    Comps.push_back(Action::OffsetOfComponent());
943    Comps.back().isBrackets = false;
944    Comps.back().U.IdentInfo = Tok.getIdentifierInfo();
945    Comps.back().LocStart = Comps.back().LocEnd = ConsumeToken();
946
947    // FIXME: This loop leaks the index expressions on error.
948    while (1) {
949      if (Tok.is(tok::period)) {
950        // offsetof-member-designator: offsetof-member-designator '.' identifier
951        Comps.push_back(Action::OffsetOfComponent());
952        Comps.back().isBrackets = false;
953        Comps.back().LocStart = ConsumeToken();
954
955        if (Tok.isNot(tok::identifier)) {
956          Diag(Tok, diag::err_expected_ident);
957          SkipUntil(tok::r_paren);
958          return ExprError();
959        }
960        Comps.back().U.IdentInfo = Tok.getIdentifierInfo();
961        Comps.back().LocEnd = ConsumeToken();
962
963      } else if (Tok.is(tok::l_square)) {
964        // offsetof-member-designator: offsetof-member-design '[' expression ']'
965        Comps.push_back(Action::OffsetOfComponent());
966        Comps.back().isBrackets = true;
967        Comps.back().LocStart = ConsumeBracket();
968        Res = ParseExpression();
969        if (Res.isInvalid()) {
970          SkipUntil(tok::r_paren);
971          return move(Res);
972        }
973        Comps.back().U.E = Res.release();
974
975        Comps.back().LocEnd =
976          MatchRHSPunctuation(tok::r_square, Comps.back().LocStart);
977      } else if (Tok.is(tok::r_paren)) {
978        Res = Actions.ActOnBuiltinOffsetOf(CurScope, StartLoc, TypeLoc, Ty,
979                                           &Comps[0], Comps.size(),
980                                           ConsumeParen());
981        break;
982      } else {
983        // Error occurred.
984        return ExprError();
985      }
986    }
987    break;
988  }
989  case tok::kw___builtin_choose_expr: {
990    OwningExprResult Cond(ParseAssignmentExpression());
991    if (Cond.isInvalid()) {
992      SkipUntil(tok::r_paren);
993      return move(Cond);
994    }
995    if (ExpectAndConsume(tok::comma, diag::err_expected_comma, "",tok::r_paren))
996      return ExprError();
997
998    OwningExprResult Expr1(ParseAssignmentExpression());
999    if (Expr1.isInvalid()) {
1000      SkipUntil(tok::r_paren);
1001      return move(Expr1);
1002    }
1003    if (ExpectAndConsume(tok::comma, diag::err_expected_comma, "",tok::r_paren))
1004      return ExprError();
1005
1006    OwningExprResult Expr2(ParseAssignmentExpression());
1007    if (Expr2.isInvalid()) {
1008      SkipUntil(tok::r_paren);
1009      return move(Expr2);
1010    }
1011    if (Tok.isNot(tok::r_paren)) {
1012      Diag(Tok, diag::err_expected_rparen);
1013      return ExprError();
1014    }
1015    Res = Actions.ActOnChooseExpr(StartLoc, Cond.release(), Expr1.release(),
1016                                  Expr2.release(), ConsumeParen());
1017    break;
1018  }
1019  case tok::kw___builtin_overload: {
1020    ExprVector ArgExprs(Actions);
1021    llvm::SmallVector<SourceLocation, 8> CommaLocs;
1022
1023    // For each iteration through the loop look for assign-expr followed by a
1024    // comma.  If there is no comma, break and attempt to match r-paren.
1025    if (Tok.isNot(tok::r_paren)) {
1026      while (1) {
1027        OwningExprResult ArgExpr(ParseAssignmentExpression());
1028        if (ArgExpr.isInvalid()) {
1029          SkipUntil(tok::r_paren);
1030          return ExprError();
1031        } else
1032          ArgExprs.push_back(ArgExpr.release());
1033
1034        if (Tok.isNot(tok::comma))
1035          break;
1036        // Move to the next argument, remember where the comma was.
1037        CommaLocs.push_back(ConsumeToken());
1038      }
1039    }
1040
1041    // Attempt to consume the r-paren
1042    if (Tok.isNot(tok::r_paren)) {
1043      Diag(Tok, diag::err_expected_rparen);
1044      SkipUntil(tok::r_paren);
1045      return ExprError();
1046    }
1047    Res = Actions.ActOnOverloadExpr(ArgExprs.take(), ArgExprs.size(),
1048                                    &CommaLocs[0], StartLoc, ConsumeParen());
1049    break;
1050  }
1051  case tok::kw___builtin_types_compatible_p:
1052    TypeTy *Ty1 = ParseTypeName();
1053
1054    if (ExpectAndConsume(tok::comma, diag::err_expected_comma, "",tok::r_paren))
1055      return ExprError();
1056
1057    TypeTy *Ty2 = ParseTypeName();
1058
1059    if (Tok.isNot(tok::r_paren)) {
1060      Diag(Tok, diag::err_expected_rparen);
1061      return ExprError();
1062    }
1063    Res = Actions.ActOnTypesCompatibleExpr(StartLoc, Ty1, Ty2, ConsumeParen());
1064    break;
1065  }
1066
1067  // These can be followed by postfix-expr pieces because they are
1068  // primary-expressions.
1069  return ParsePostfixExpressionSuffix(move(Res));
1070}
1071
1072/// ParseParenExpression - This parses the unit that starts with a '(' token,
1073/// based on what is allowed by ExprType.  The actual thing parsed is returned
1074/// in ExprType.
1075///
1076///       primary-expression: [C99 6.5.1]
1077///         '(' expression ')'
1078/// [GNU]   '(' compound-statement ')'      (if !ParenExprOnly)
1079///       postfix-expression: [C99 6.5.2]
1080///         '(' type-name ')' '{' initializer-list '}'
1081///         '(' type-name ')' '{' initializer-list ',' '}'
1082///       cast-expression: [C99 6.5.4]
1083///         '(' type-name ')' cast-expression
1084///
1085Parser::OwningExprResult
1086Parser::ParseParenExpression(ParenParseOption &ExprType,
1087                             TypeTy *&CastTy, SourceLocation &RParenLoc) {
1088  assert(Tok.is(tok::l_paren) && "Not a paren expr!");
1089  SourceLocation OpenLoc = ConsumeParen();
1090  OwningExprResult Result(Actions, true);
1091  CastTy = 0;
1092
1093  if (ExprType >= CompoundStmt && Tok.is(tok::l_brace)) {
1094    Diag(Tok, diag::ext_gnu_statement_expr);
1095    OwningStmtResult Stmt(ParseCompoundStatement(true));
1096    ExprType = CompoundStmt;
1097
1098    // If the substmt parsed correctly, build the AST node.
1099    if (!Stmt.isInvalid() && Tok.is(tok::r_paren))
1100      Result = Actions.ActOnStmtExpr(
1101        OpenLoc, Stmt.release(), Tok.getLocation());
1102
1103  } else if (ExprType >= CompoundLiteral && isTypeIdInParens()) {
1104    // Otherwise, this is a compound literal expression or cast expression.
1105    TypeTy *Ty = ParseTypeName();
1106
1107    // Match the ')'.
1108    if (Tok.is(tok::r_paren))
1109      RParenLoc = ConsumeParen();
1110    else
1111      MatchRHSPunctuation(tok::r_paren, OpenLoc);
1112
1113    if (Tok.is(tok::l_brace)) {
1114      if (!getLang().C99)   // Compound literals don't exist in C90.
1115        Diag(OpenLoc, diag::ext_c99_compound_literal);
1116      Result = ParseInitializer();
1117      ExprType = CompoundLiteral;
1118      if (!Result.isInvalid())
1119        return Actions.ActOnCompoundLiteral(OpenLoc, Ty, RParenLoc,
1120                                            move_arg(Result));
1121      return move(Result);
1122    }
1123
1124    if (ExprType == CastExpr) {
1125      // Note that this doesn't parse the subsequence cast-expression, it just
1126      // returns the parsed type to the callee.
1127      ExprType = CastExpr;
1128      CastTy = Ty;
1129      return OwningExprResult(Actions);
1130    }
1131
1132    Diag(Tok, diag::err_expected_lbrace_in_compound_literal);
1133    return ExprError();
1134  } else {
1135    Result = ParseExpression();
1136    ExprType = SimpleExpr;
1137    if (!Result.isInvalid() && Tok.is(tok::r_paren))
1138      Result = Actions.ActOnParenExpr(OpenLoc, Tok.getLocation(),
1139                                      move_arg(Result));
1140  }
1141
1142  // Match the ')'.
1143  if (Result.isInvalid()) {
1144    SkipUntil(tok::r_paren);
1145    return ExprError();
1146  }
1147
1148  if (Tok.is(tok::r_paren))
1149    RParenLoc = ConsumeParen();
1150  else
1151    MatchRHSPunctuation(tok::r_paren, OpenLoc);
1152
1153  return move(Result);
1154}
1155
1156/// ParseStringLiteralExpression - This handles the various token types that
1157/// form string literals, and also handles string concatenation [C99 5.1.1.2,
1158/// translation phase #6].
1159///
1160///       primary-expression: [C99 6.5.1]
1161///         string-literal
1162Parser::OwningExprResult Parser::ParseStringLiteralExpression() {
1163  assert(isTokenStringLiteral() && "Not a string literal!");
1164
1165  // String concat.  Note that keywords like __func__ and __FUNCTION__ are not
1166  // considered to be strings for concatenation purposes.
1167  llvm::SmallVector<Token, 4> StringToks;
1168
1169  do {
1170    StringToks.push_back(Tok);
1171    ConsumeStringToken();
1172  } while (isTokenStringLiteral());
1173
1174  // Pass the set of string tokens, ready for concatenation, to the actions.
1175  return Actions.ActOnStringLiteral(&StringToks[0], StringToks.size());
1176}
1177
1178/// ParseExpressionList - Used for C/C++ (argument-)expression-list.
1179///
1180///       argument-expression-list:
1181///         assignment-expression
1182///         argument-expression-list , assignment-expression
1183///
1184/// [C++] expression-list:
1185/// [C++]   assignment-expression
1186/// [C++]   expression-list , assignment-expression
1187///
1188bool Parser::ParseExpressionList(ExprListTy &Exprs, CommaLocsTy &CommaLocs) {
1189  while (1) {
1190    OwningExprResult Expr(ParseAssignmentExpression());
1191    if (Expr.isInvalid())
1192      return true;
1193
1194    Exprs.push_back(Expr.release());
1195
1196    if (Tok.isNot(tok::comma))
1197      return false;
1198    // Move to the next argument, remember where the comma was.
1199    CommaLocs.push_back(ConsumeToken());
1200  }
1201}
1202
1203/// ParseBlockLiteralExpression - Parse a block literal, which roughly looks
1204/// like ^(int x){ return x+1; }
1205///
1206///         block-literal:
1207/// [clang]   '^' block-args[opt] compound-statement
1208/// [clang] block-args:
1209/// [clang]   '(' parameter-list ')'
1210///
1211Parser::OwningExprResult Parser::ParseBlockLiteralExpression() {
1212  assert(Tok.is(tok::caret) && "block literal starts with ^");
1213  SourceLocation CaretLoc = ConsumeToken();
1214
1215  // Enter a scope to hold everything within the block.  This includes the
1216  // argument decls, decls within the compound expression, etc.  This also
1217  // allows determining whether a variable reference inside the block is
1218  // within or outside of the block.
1219  ParseScope BlockScope(this, Scope::BlockScope|Scope::FnScope|Scope::BreakScope|
1220                              Scope::ContinueScope|Scope::DeclScope);
1221
1222  // Inform sema that we are starting a block.
1223  Actions.ActOnBlockStart(CaretLoc, CurScope);
1224
1225  // Parse the return type if present.
1226  DeclSpec DS;
1227  Declarator ParamInfo(DS, Declarator::PrototypeContext);
1228
1229  // If this block has arguments, parse them.  There is no ambiguity here with
1230  // the expression case, because the expression case requires a parameter list.
1231  if (Tok.is(tok::l_paren)) {
1232    ParseParenDeclarator(ParamInfo);
1233    // Parse the pieces after the identifier as if we had "int(...)".
1234    ParamInfo.SetIdentifier(0, CaretLoc);
1235    if (ParamInfo.getInvalidType()) {
1236      // If there was an error parsing the arguments, they may have tried to use
1237      // ^(x+y) which requires an argument list.  Just skip the whole block
1238      // literal.
1239      return ExprError();
1240    }
1241  } else {
1242    // Otherwise, pretend we saw (void).
1243    ParamInfo.AddTypeInfo(DeclaratorChunk::getFunction(true, false,
1244                                                       0, 0, 0, CaretLoc,
1245                                                       ParamInfo));
1246  }
1247
1248  // Inform sema that we are starting a block.
1249  Actions.ActOnBlockArguments(ParamInfo);
1250
1251  OwningExprResult Result(Actions, true);
1252  if (Tok.is(tok::l_brace)) {
1253    OwningStmtResult Stmt(ParseCompoundStatementBody());
1254    if (!Stmt.isInvalid()) {
1255      Result = Actions.ActOnBlockStmtExpr(CaretLoc, Stmt.release(), CurScope);
1256    } else {
1257      Actions.ActOnBlockError(CaretLoc, CurScope);
1258    }
1259  } else {
1260    // Saw something like: ^expr
1261    Diag(Tok, diag::err_expected_expression);
1262    return ExprError();
1263  }
1264  return move(Result);
1265}
1266
1267