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(Tok
, 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 SourceLocation StartLoc
= ConsumeBracket();
145 // If Objective-C is enabled and this is a typename (class message
146 // send) or send to 'super', parse this as a message send
147 // expression. We handle C++ and C separately, since C++ requires
148 // much more complicated parsing.
149 if (getLang().ObjC1
&& getLang().CPlusPlus
) {
151 if (Tok
.is(tok::identifier
) && Tok
.getIdentifierInfo() == Ident_super
&&
152 NextToken().isNot(tok::period
) &&
153 getCurScope()->isInObjcMethodScope()) {
154 CheckArrayDesignatorSyntax(*this, StartLoc
, Desig
);
155 return ParseAssignmentExprWithObjCMessageExprStart(StartLoc
,
161 // Parse the receiver, which is either a type or an expression.
164 if (ParseObjCXXMessageReceiver(IsExpr
, TypeOrExpr
)) {
165 SkipUntil(tok::r_square
);
169 // If the receiver was a type, we have a class message; parse
172 CheckArrayDesignatorSyntax(*this, StartLoc
, Desig
);
173 return ParseAssignmentExprWithObjCMessageExprStart(StartLoc
,
175 ParsedType::getFromOpaquePtr(TypeOrExpr
),
179 // If the receiver was an expression, we still don't know
180 // whether we have a message send or an array designator; just
181 // adopt the expression for further analysis below.
182 // FIXME: potentially-potentially evaluated expression above?
183 Idx
= ExprResult(static_cast<Expr
*>(TypeOrExpr
));
184 } else if (getLang().ObjC1
&& Tok
.is(tok::identifier
)) {
185 IdentifierInfo
*II
= Tok
.getIdentifierInfo();
186 SourceLocation IILoc
= Tok
.getLocation();
187 ParsedType ReceiverType
;
188 // Three cases. This is a message send to a type: [type foo]
189 // This is a message send to super: [super foo]
190 // This is a message sent to an expr: [super.bar foo]
191 switch (Sema::ObjCMessageKind Kind
192 = Actions
.getObjCMessageKind(getCurScope(), II
, IILoc
,
194 NextToken().is(tok::period
),
196 case Sema::ObjCSuperMessage
:
197 case Sema::ObjCClassMessage
:
198 CheckArrayDesignatorSyntax(*this, StartLoc
, Desig
);
199 if (Kind
== Sema::ObjCSuperMessage
)
200 return ParseAssignmentExprWithObjCMessageExprStart(StartLoc
,
204 ConsumeToken(); // the identifier
206 SkipUntil(tok::r_square
);
210 return ParseAssignmentExprWithObjCMessageExprStart(StartLoc
,
215 case Sema::ObjCInstanceMessage
:
216 // Fall through; we'll just parse the expression and
217 // (possibly) treat this like an Objective-C message send
223 // Parse the index expression, if we haven't already gotten one
224 // above (which can only happen in Objective-C++).
225 // Note that we parse this as an assignment expression, not a constant
226 // expression (allowing *=, =, etc) to handle the objc case. Sema needs
227 // to validate that the expression is a constant.
228 // FIXME: We also need to tell Sema that we're in a
229 // potentially-potentially evaluated context.
231 Idx
= ParseAssignmentExpression();
232 if (Idx
.isInvalid()) {
233 SkipUntil(tok::r_square
);
238 // Given an expression, we could either have a designator (if the next
239 // tokens are '...' or ']' or an objc message send. If this is an objc
240 // message send, handle it now. An objc-message send is the start of
241 // an assignment-expression production.
242 if (getLang().ObjC1
&& Tok
.isNot(tok::ellipsis
) &&
243 Tok
.isNot(tok::r_square
)) {
244 CheckArrayDesignatorSyntax(*this, Tok
.getLocation(), Desig
);
245 return ParseAssignmentExprWithObjCMessageExprStart(StartLoc
,
251 // If this is a normal array designator, remember it.
252 if (Tok
.isNot(tok::ellipsis
)) {
253 Desig
.AddDesignator(Designator::getArray(Idx
.release(), StartLoc
));
255 // Handle the gnu array range extension.
256 Diag(Tok
, diag::ext_gnu_array_range
);
257 SourceLocation EllipsisLoc
= ConsumeToken();
259 ExprResult
RHS(ParseConstantExpression());
260 if (RHS
.isInvalid()) {
261 SkipUntil(tok::r_square
);
264 Desig
.AddDesignator(Designator::getArrayRange(Idx
.release(),
266 StartLoc
, EllipsisLoc
));
269 SourceLocation EndLoc
= MatchRHSPunctuation(tok::r_square
, StartLoc
);
270 Desig
.getDesignator(Desig
.getNumDesignators() - 1).setRBracketLoc(EndLoc
);
273 // Okay, we're done with the designator sequence. We know that there must be
274 // at least one designator, because the only case we can get into this method
275 // without a designator is when we have an objc message send. That case is
276 // handled and returned from above.
277 assert(!Desig
.empty() && "Designator is empty?");
279 // Handle a normal designator sequence end, which is an equal.
280 if (Tok
.is(tok::equal
)) {
281 SourceLocation EqualLoc
= ConsumeToken();
282 return Actions
.ActOnDesignatedInitializer(Desig
, EqualLoc
, false,
286 // We read some number of designators and found something that isn't an = or
287 // an initializer. If we have exactly one array designator, this
288 // is the GNU 'designation: array-designator' extension. Otherwise, it is a
290 if (Desig
.getNumDesignators() == 1 &&
291 (Desig
.getDesignator(0).isArrayDesignator() ||
292 Desig
.getDesignator(0).isArrayRangeDesignator())) {
293 Diag(Tok
, diag::ext_gnu_missing_equal_designator
)
294 << FixItHint::CreateInsertion(Tok
.getLocation(), "= ");
295 return Actions
.ActOnDesignatedInitializer(Desig
, Tok
.getLocation(),
296 true, ParseInitializer());
299 Diag(Tok
, diag::err_expected_equal_designator
);
304 /// ParseBraceInitializer - Called when parsing an initializer that has a
305 /// leading open brace.
307 /// initializer: [C99 6.7.8]
308 /// '{' initializer-list '}'
309 /// '{' initializer-list ',' '}'
312 /// initializer-list:
313 /// designation[opt] initializer ...[opt]
314 /// initializer-list ',' designation[opt] initializer ...[opt]
316 ExprResult
Parser::ParseBraceInitializer() {
317 InMessageExpressionRAIIObject
InMessage(*this, false);
319 SourceLocation LBraceLoc
= ConsumeBrace();
321 /// InitExprs - This is the actual list of expressions contained in the
323 ExprVector
InitExprs(Actions
);
325 if (Tok
.is(tok::r_brace
)) {
326 // Empty initializers are a C++ feature and a GNU extension to C.
327 if (!getLang().CPlusPlus
)
328 Diag(LBraceLoc
, diag::ext_gnu_empty_initializer
);
330 return Actions
.ActOnInitList(LBraceLoc
, MultiExprArg(Actions
),
334 bool InitExprsOk
= true;
337 // Parse: designation[opt] initializer
339 // If we know that this cannot be a designation, just parse the nested
340 // initializer directly.
342 if (MayBeDesignationStart(Tok
.getKind(), PP
))
343 SubElt
= ParseInitializerWithPotentialDesignator();
345 SubElt
= ParseInitializer();
347 if (Tok
.is(tok::ellipsis
))
348 SubElt
= Actions
.ActOnPackExpansion(SubElt
.get(), ConsumeToken());
350 // If we couldn't parse the subelement, bail out.
351 if (!SubElt
.isInvalid()) {
352 InitExprs
.push_back(SubElt
.release());
356 // We have two ways to try to recover from this error: if the code looks
357 // gramatically ok (i.e. we have a comma coming up) try to continue
358 // parsing the rest of the initializer. This allows us to emit
359 // diagnostics for later elements that we find. If we don't see a comma,
360 // assume there is a parse error, and just skip to recover.
361 // FIXME: This comment doesn't sound right. If there is a r_brace
362 // immediately, it can't be an error, since there is no other way of
363 // leaving this loop except through this if.
364 if (Tok
.isNot(tok::comma
)) {
365 SkipUntil(tok::r_brace
, false, true);
370 // If we don't have a comma continued list, we're done.
371 if (Tok
.isNot(tok::comma
)) break;
373 // TODO: save comma locations if some client cares.
376 // Handle trailing comma.
377 if (Tok
.is(tok::r_brace
)) break;
379 if (InitExprsOk
&& Tok
.is(tok::r_brace
))
380 return Actions
.ActOnInitList(LBraceLoc
, move_arg(InitExprs
),
384 MatchRHSPunctuation(tok::r_brace
, LBraceLoc
);
385 return ExprError(); // an error occurred.