forked from OSchip/llvm-project
260 lines
9.0 KiB
C++
260 lines
9.0 KiB
C++
//===--- ParseInit.cpp - Initializer Parsing ------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements initializer parsing as specified by C99 6.7.8.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Parse/Designator.h"
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#include "clang/Parse/Parser.h"
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#include "clang/Basic/Diagnostic.h"
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#include "llvm/ADT/SmallString.h"
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using namespace clang;
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/// MayBeDesignationStart - Return true if this token might be the start of a
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/// designator. If we can tell it is impossible that it is a designator, return
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/// false.
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static bool MayBeDesignationStart(tok::TokenKind K) {
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switch (K) {
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default: return false;
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case tok::period: // designator: '.' identifier
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case tok::l_square: // designator: array-designator
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case tok::identifier: // designation: identifier ':'
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return true;
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}
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}
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/// ParseInitializerWithPotentialDesignator - Parse the 'initializer' production
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/// checking to see if the token stream starts with a designator.
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///
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/// designation:
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/// designator-list '='
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/// [GNU] array-designator
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/// [GNU] identifier ':'
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///
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/// designator-list:
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/// designator
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/// designator-list designator
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///
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/// designator:
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/// array-designator
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/// '.' identifier
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///
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/// array-designator:
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/// '[' constant-expression ']'
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/// [GNU] '[' constant-expression '...' constant-expression ']'
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///
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/// NOTE: [OBC] allows '[ objc-receiver objc-message-args ]' as an
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/// initializer (because it is an expression). We need to consider this case
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/// when parsing array designators.
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///
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Parser::ExprResult Parser::
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ParseInitializerWithPotentialDesignator(InitListDesignations &Designations,
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unsigned InitNum) {
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// If this is the old-style GNU extension:
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// designation ::= identifier ':'
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// Handle it as a field designator. Otherwise, this must be the start of a
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// normal expression.
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if (Tok.is(tok::identifier)) {
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if (NextToken().is(tok::colon)) {
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Diag(Tok, diag::ext_gnu_old_style_field_designator);
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Designation &D = Designations.CreateDesignation(InitNum);
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D.AddDesignator(Designator::getField(Tok.getIdentifierInfo()));
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ConsumeToken(); // Eat the identifier.
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assert(Tok.is(tok::colon) && "NextToken() not working properly!");
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ConsumeToken();
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return ParseInitializer();
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}
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// Otherwise, parse the assignment-expression.
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return ParseAssignmentExpression();
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}
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// Parse each designator in the designator list until we find an initializer.
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while (1) {
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switch (Tok.getKind()) {
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case tok::equal:
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// We read some number (at least one due to the grammar we implemented)
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// of designators and found an '=' sign. The following tokens must be
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// the initializer.
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ConsumeToken();
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return ParseInitializer();
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default: {
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// We read some number (at least one due to the grammar we implemented)
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// of designators and found something that isn't an = or an initializer.
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// If we have exactly one array designator [TODO CHECK], this is the GNU
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// 'designation: array-designator' extension. Otherwise, it is a parse
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// error.
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SourceLocation Loc = Tok.getLocation();
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ExprResult Init = ParseInitializer();
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if (Init.isInvalid) return Init;
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Diag(Tok, diag::ext_gnu_missing_equal_designator);
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return Init;
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}
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case tok::period:
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// designator: '.' identifier
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ConsumeToken();
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if (ExpectAndConsume(tok::identifier, diag::err_expected_ident))
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return ExprResult(true);
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break;
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case tok::l_square: {
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// array-designator: '[' constant-expression ']'
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// array-designator: '[' constant-expression '...' constant-expression ']'
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// When designation is empty, this can be '[' objc-message-expr ']'. Note
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// that we also have the case of [4][foo bar], which is the gnu designator
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// extension + objc message send.
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SourceLocation StartLoc = ConsumeBracket();
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// If Objective-C is enabled and this is a typename or other identifier
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// receiver, parse this as a message send expression.
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if (getLang().ObjC1 && isTokObjCMessageIdentifierReceiver()) {
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// FIXME: Emit ext_gnu_missing_equal_designator for inits like
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// [4][foo bar].
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IdentifierInfo *Name = Tok.getIdentifierInfo();
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ConsumeToken();
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return ParseAssignmentExprWithObjCMessageExprStart(StartLoc, Name, 0);
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}
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// Note that we parse this as an assignment expression, not a constant
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// expression (allowing *=, =, etc) to handle the objc case. Sema needs
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// to validate that the expression is a constant.
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ExprResult Idx = ParseAssignmentExpression();
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if (Idx.isInvalid) {
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SkipUntil(tok::r_square);
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return Idx;
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}
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// Given an expression, we could either have a designator (if the next
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// tokens are '...' or ']' or an objc message send. If this is an objc
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// message send, handle it now. An objc-message send is the start of
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// an assignment-expression production.
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if (getLang().ObjC1 && Tok.isNot(tok::ellipsis) &&
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Tok.isNot(tok::r_square)) {
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// FIXME: Emit ext_gnu_missing_equal_designator for inits like
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// [4][foo bar].
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return ParseAssignmentExprWithObjCMessageExprStart(StartLoc, 0,Idx.Val);
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}
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// Handle the gnu array range extension.
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if (Tok.is(tok::ellipsis)) {
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Diag(Tok, diag::ext_gnu_array_range);
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ConsumeToken();
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ExprResult RHS = ParseConstantExpression();
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if (RHS.isInvalid) {
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SkipUntil(tok::r_square);
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return RHS;
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}
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}
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MatchRHSPunctuation(tok::r_square, StartLoc);
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break;
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}
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}
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}
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}
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/// ParseInitializer
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/// initializer: [C99 6.7.8]
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/// assignment-expression
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/// '{' initializer-list '}'
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/// '{' initializer-list ',' '}'
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/// [GNU] '{' '}'
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///
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/// initializer-list:
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/// designation[opt] initializer
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/// initializer-list ',' designation[opt] initializer
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///
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Parser::ExprResult Parser::ParseInitializer() {
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// TODO: Split this up into ParseInitializer + ParseBraceInitializer, make
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// ParseInitializer inline so that the non-brace case is short-cut.
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if (Tok.isNot(tok::l_brace))
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return ParseAssignmentExpression();
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SourceLocation LBraceLoc = ConsumeBrace();
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// We support empty initializers, but tell the user that they aren't using
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// C99-clean code.
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if (Tok.is(tok::r_brace)) {
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Diag(LBraceLoc, diag::ext_gnu_empty_initializer);
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// Match the '}'.
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return Actions.ActOnInitList(LBraceLoc, 0, 0, ConsumeBrace());
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}
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/// InitExprs - This is the actual list of expressions contained in the
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/// initializer.
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llvm::SmallVector<ExprTy*, 8> InitExprs;
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/// ExprDesignators - For each initializer, keep track of the designator that
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/// was specified for it, if any.
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InitListDesignations InitExprDesignations(Actions);
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bool InitExprsOk = true;
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while (1) {
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// Parse: designation[opt] initializer
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// If we know that this cannot be a designation, just parse the nested
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// initializer directly.
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ExprResult SubElt;
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if (!MayBeDesignationStart(Tok.getKind()))
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SubElt = ParseInitializer();
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else
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SubElt = ParseInitializerWithPotentialDesignator(InitExprDesignations,
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InitExprs.size());
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// If we couldn't parse the subelement, bail out.
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if (!SubElt.isInvalid) {
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InitExprs.push_back(SubElt.Val);
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} else {
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InitExprsOk = false;
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// We have two ways to try to recover from this error: if the code looks
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// gramatically ok (i.e. we have a comma coming up) try to continue
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// parsing the rest of the initializer. This allows us to emit
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// diagnostics for later elements that we find. If we don't see a comma,
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// assume there is a parse error, and just skip to recover.
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if (Tok.isNot(tok::comma)) {
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SkipUntil(tok::r_brace, false, true);
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break;
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}
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}
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// If we don't have a comma continued list, we're done.
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if (Tok.isNot(tok::comma)) break;
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// TODO: save comma locations if some client cares.
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ConsumeToken();
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// Handle trailing comma.
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if (Tok.is(tok::r_brace)) break;
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}
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if (InitExprsOk && Tok.is(tok::r_brace))
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return Actions.ActOnInitList(LBraceLoc, &InitExprs[0], InitExprs.size(),
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ConsumeBrace());
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// On error, delete any parsed subexpressions.
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for (unsigned i = 0, e = InitExprs.size(); i != e; ++i)
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Actions.DeleteExpr(InitExprs[i]);
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// Match the '}'.
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MatchRHSPunctuation(tok::r_brace, LBraceLoc);
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return ExprResult(true); // an error occurred.
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}
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