1 //===--- ParseInit.cpp - Initializer Parsing ------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements initializer parsing as specified by C99 6.7.8.
12 //===----------------------------------------------------------------------===//
14 #include "clang/Parse/Parser.h"
15 #include "clang/Parse/ParseDiagnostic.h"
16 #include "RAIIObjectsForParser.h"
17 #include "clang/Sema/Designator.h"
18 #include "clang/Sema/Scope.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/Support/raw_ostream.h"
21 using namespace clang;
24 /// MayBeDesignationStart - Return true if this token might be the start of a
25 /// designator. If we can tell it is impossible that it is a designator, return
27 static bool MayBeDesignationStart(tok::TokenKind K, Preprocessor &PP) {
29 default: return false;
30 case tok::period: // designator: '.' identifier
31 case tok::l_square: // designator: array-designator
33 case tok::identifier: // designation: identifier ':'
34 return PP.LookAhead(0).is(tok::colon);
38 static void CheckArrayDesignatorSyntax(Parser &P, SourceLocation Loc,
40 // If we have exactly one array designator, this used the GNU
41 // 'designation: array-designator' extension, otherwise there should be no
42 // designators at all!
43 if (Desig.getNumDesignators() == 1 &&
44 (Desig.getDesignator(0).isArrayDesignator() ||
45 Desig.getDesignator(0).isArrayRangeDesignator()))
46 P.Diag(Loc, diag::ext_gnu_missing_equal_designator);
47 else if (Desig.getNumDesignators() > 0)
48 P.Diag(Loc, diag::err_expected_equal_designator);
51 /// ParseInitializerWithPotentialDesignator - Parse the 'initializer' production
52 /// checking to see if the token stream starts with a designator.
55 /// designator-list '='
56 /// [GNU] array-designator
57 /// [GNU] identifier ':'
61 /// designator-list designator
68 /// '[' constant-expression ']'
69 /// [GNU] '[' constant-expression '...' constant-expression ']'
71 /// NOTE: [OBC] allows '[ objc-receiver objc-message-args ]' as an
72 /// initializer (because it is an expression). We need to consider this case
73 /// when parsing array designators.
75 ExprResult Parser::ParseInitializerWithPotentialDesignator() {
77 // If this is the old-style GNU extension:
78 // designation ::= identifier ':'
79 // Handle it as a field designator. Otherwise, this must be the start of a
81 if (Tok.is(tok::identifier)) {
82 const IdentifierInfo *FieldName = Tok.getIdentifierInfo();
84 llvm::SmallString<256> NewSyntax;
85 llvm::raw_svector_ostream(NewSyntax) << '.' << FieldName->getName()
88 SourceLocation NameLoc = ConsumeToken(); // Eat the identifier.
90 assert(Tok.is(tok::colon) && "MayBeDesignationStart not working properly!");
91 SourceLocation ColonLoc = ConsumeToken();
93 Diag(NameLoc, diag::ext_gnu_old_style_field_designator)
94 << FixItHint::CreateReplacement(SourceRange(NameLoc, ColonLoc),
98 D.AddDesignator(Designator::getField(FieldName, SourceLocation(), NameLoc));
99 return Actions.ActOnDesignatedInitializer(D, ColonLoc, true,
103 // Desig - This is initialized when we see our first designator. We may have
104 // an objc message send with no designator, so we don't want to create this
108 // Parse each designator in the designator list until we find an initializer.
109 while (Tok.is(tok::period) || Tok.is(tok::l_square)) {
110 if (Tok.is(tok::period)) {
111 // designator: '.' identifier
112 SourceLocation DotLoc = ConsumeToken();
114 if (Tok.isNot(tok::identifier)) {
115 Diag(Tok.getLocation(), diag::err_expected_field_designator);
119 Desig.AddDesignator(Designator::getField(Tok.getIdentifierInfo(), DotLoc,
121 ConsumeToken(); // Eat the identifier.
125 // We must have either an array designator now or an objc message send.
126 assert(Tok.is(tok::l_square) && "Unexpected token!");
128 // Handle the two forms of array designator:
129 // array-designator: '[' constant-expression ']'
130 // array-designator: '[' constant-expression '...' constant-expression ']'
132 // Also, we have to handle the case where the expression after the
133 // designator an an objc message send: '[' objc-message-expr ']'.
134 // Interesting cases are:
135 // [foo bar] -> objc message send
136 // [foo] -> array designator
137 // [foo ... bar] -> array designator
138 // [4][foo bar] -> obsolete GNU designation with objc message send.
140 InMessageExpressionRAIIObject InMessage(*this, true);
142 BalancedDelimiterTracker T(*this, tok::l_square);
144 SourceLocation StartLoc = T.getOpenLocation();
148 // If Objective-C is enabled and this is a typename (class message
149 // send) or send to 'super', parse this as a message send
150 // expression. We handle C++ and C separately, since C++ requires
151 // much more complicated parsing.
152 if (getLang().ObjC1 && getLang().CPlusPlus) {
154 if (Tok.is(tok::identifier) && Tok.getIdentifierInfo() == Ident_super &&
155 NextToken().isNot(tok::period) &&
156 getCurScope()->isInObjcMethodScope()) {
157 CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
158 return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
164 // Parse the receiver, which is either a type or an expression.
167 if (ParseObjCXXMessageReceiver(IsExpr, TypeOrExpr)) {
168 SkipUntil(tok::r_square);
172 // If the receiver was a type, we have a class message; parse
175 CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
176 return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
178 ParsedType::getFromOpaquePtr(TypeOrExpr),
182 // If the receiver was an expression, we still don't know
183 // whether we have a message send or an array designator; just
184 // adopt the expression for further analysis below.
185 // FIXME: potentially-potentially evaluated expression above?
186 Idx = ExprResult(static_cast<Expr*>(TypeOrExpr));
187 } else if (getLang().ObjC1 && Tok.is(tok::identifier)) {
188 IdentifierInfo *II = Tok.getIdentifierInfo();
189 SourceLocation IILoc = Tok.getLocation();
190 ParsedType ReceiverType;
191 // Three cases. This is a message send to a type: [type foo]
192 // This is a message send to super: [super foo]
193 // This is a message sent to an expr: [super.bar foo]
194 switch (Sema::ObjCMessageKind Kind
195 = Actions.getObjCMessageKind(getCurScope(), II, IILoc,
197 NextToken().is(tok::period),
199 case Sema::ObjCSuperMessage:
200 case Sema::ObjCClassMessage:
201 CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
202 if (Kind == Sema::ObjCSuperMessage)
203 return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
207 ConsumeToken(); // the identifier
209 SkipUntil(tok::r_square);
213 return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
218 case Sema::ObjCInstanceMessage:
219 // Fall through; we'll just parse the expression and
220 // (possibly) treat this like an Objective-C message send
226 // Parse the index expression, if we haven't already gotten one
227 // above (which can only happen in Objective-C++).
228 // Note that we parse this as an assignment expression, not a constant
229 // expression (allowing *=, =, etc) to handle the objc case. Sema needs
230 // to validate that the expression is a constant.
231 // FIXME: We also need to tell Sema that we're in a
232 // potentially-potentially evaluated context.
234 Idx = ParseAssignmentExpression();
235 if (Idx.isInvalid()) {
236 SkipUntil(tok::r_square);
241 // Given an expression, we could either have a designator (if the next
242 // tokens are '...' or ']' or an objc message send. If this is an objc
243 // message send, handle it now. An objc-message send is the start of
244 // an assignment-expression production.
245 if (getLang().ObjC1 && Tok.isNot(tok::ellipsis) &&
246 Tok.isNot(tok::r_square)) {
247 CheckArrayDesignatorSyntax(*this, Tok.getLocation(), Desig);
248 return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
254 // If this is a normal array designator, remember it.
255 if (Tok.isNot(tok::ellipsis)) {
256 Desig.AddDesignator(Designator::getArray(Idx.release(), StartLoc));
258 // Handle the gnu array range extension.
259 Diag(Tok, diag::ext_gnu_array_range);
260 SourceLocation EllipsisLoc = ConsumeToken();
262 ExprResult RHS(ParseConstantExpression());
263 if (RHS.isInvalid()) {
264 SkipUntil(tok::r_square);
267 Desig.AddDesignator(Designator::getArrayRange(Idx.release(),
269 StartLoc, EllipsisLoc));
273 Desig.getDesignator(Desig.getNumDesignators() - 1).setRBracketLoc(
274 T.getCloseLocation());
277 // Okay, we're done with the designator sequence. We know that there must be
278 // at least one designator, because the only case we can get into this method
279 // without a designator is when we have an objc message send. That case is
280 // handled and returned from above.
281 assert(!Desig.empty() && "Designator is empty?");
283 // Handle a normal designator sequence end, which is an equal.
284 if (Tok.is(tok::equal)) {
285 SourceLocation EqualLoc = ConsumeToken();
286 return Actions.ActOnDesignatedInitializer(Desig, EqualLoc, false,
290 // We read some number of designators and found something that isn't an = or
291 // an initializer. If we have exactly one array designator, this
292 // is the GNU 'designation: array-designator' extension. Otherwise, it is a
294 if (Desig.getNumDesignators() == 1 &&
295 (Desig.getDesignator(0).isArrayDesignator() ||
296 Desig.getDesignator(0).isArrayRangeDesignator())) {
297 Diag(Tok, diag::ext_gnu_missing_equal_designator)
298 << FixItHint::CreateInsertion(Tok.getLocation(), "= ");
299 return Actions.ActOnDesignatedInitializer(Desig, Tok.getLocation(),
300 true, ParseInitializer());
303 Diag(Tok, diag::err_expected_equal_designator);
308 /// ParseBraceInitializer - Called when parsing an initializer that has a
309 /// leading open brace.
311 /// initializer: [C99 6.7.8]
312 /// '{' initializer-list '}'
313 /// '{' initializer-list ',' '}'
316 /// initializer-list:
317 /// designation[opt] initializer ...[opt]
318 /// initializer-list ',' designation[opt] initializer ...[opt]
320 ExprResult Parser::ParseBraceInitializer() {
321 InMessageExpressionRAIIObject InMessage(*this, false);
323 BalancedDelimiterTracker T(*this, tok::l_brace);
325 SourceLocation LBraceLoc = T.getOpenLocation();
327 /// InitExprs - This is the actual list of expressions contained in the
329 ExprVector InitExprs(Actions);
331 if (Tok.is(tok::r_brace)) {
332 // Empty initializers are a C++ feature and a GNU extension to C.
333 if (!getLang().CPlusPlus)
334 Diag(LBraceLoc, diag::ext_gnu_empty_initializer);
336 return Actions.ActOnInitList(LBraceLoc, MultiExprArg(Actions),
340 bool InitExprsOk = true;
343 // Parse: designation[opt] initializer
345 // If we know that this cannot be a designation, just parse the nested
346 // initializer directly.
348 if (MayBeDesignationStart(Tok.getKind(), PP))
349 SubElt = ParseInitializerWithPotentialDesignator();
351 SubElt = ParseInitializer();
353 if (Tok.is(tok::ellipsis))
354 SubElt = Actions.ActOnPackExpansion(SubElt.get(), ConsumeToken());
356 // If we couldn't parse the subelement, bail out.
357 if (!SubElt.isInvalid()) {
358 InitExprs.push_back(SubElt.release());
362 // We have two ways to try to recover from this error: if the code looks
363 // grammatically ok (i.e. we have a comma coming up) try to continue
364 // parsing the rest of the initializer. This allows us to emit
365 // diagnostics for later elements that we find. If we don't see a comma,
366 // assume there is a parse error, and just skip to recover.
367 // FIXME: This comment doesn't sound right. If there is a r_brace
368 // immediately, it can't be an error, since there is no other way of
369 // leaving this loop except through this if.
370 if (Tok.isNot(tok::comma)) {
371 SkipUntil(tok::r_brace, false, true);
376 // If we don't have a comma continued list, we're done.
377 if (Tok.isNot(tok::comma)) break;
379 // TODO: save comma locations if some client cares.
382 // Handle trailing comma.
383 if (Tok.is(tok::r_brace)) break;
386 bool closed = !T.consumeClose();
388 if (InitExprsOk && closed)
389 return Actions.ActOnInitList(LBraceLoc, move_arg(InitExprs),
390 T.getCloseLocation());
392 return ExprError(); // an error occurred.