546 lines
20 KiB
C++
546 lines
20 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/Parser.h"
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#include "RAIIObjectsForParser.h"
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#include "clang/Parse/ParseDiagnostic.h"
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#include "clang/Sema/Designator.h"
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#include "clang/Sema/Scope.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace clang;
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/// MayBeDesignationStart - Return true if the current token might be the start
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/// of a designator. If we can tell it is impossible that it is a designator,
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/// return false.
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bool Parser::MayBeDesignationStart() {
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switch (Tok.getKind()) {
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default:
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return false;
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case tok::period: // designator: '.' identifier
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return true;
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case tok::l_square: { // designator: array-designator
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if (!PP.getLangOpts().CPlusPlus11)
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return true;
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// C++11 lambda expressions and C99 designators can be ambiguous all the
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// way through the closing ']' and to the next character. Handle the easy
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// cases here, and fall back to tentative parsing if those fail.
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switch (PP.LookAhead(0).getKind()) {
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case tok::equal:
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case tok::r_square:
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// Definitely starts a lambda expression.
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return false;
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case tok::amp:
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case tok::kw_this:
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case tok::identifier:
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// We have to do additional analysis, because these could be the
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// start of a constant expression or a lambda capture list.
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break;
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default:
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// Anything not mentioned above cannot occur following a '[' in a
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// lambda expression.
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return true;
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}
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// Handle the complicated case below.
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break;
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}
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case tok::identifier: // designation: identifier ':'
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return PP.LookAhead(0).is(tok::colon);
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}
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// Parse up to (at most) the token after the closing ']' to determine
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// whether this is a C99 designator or a lambda.
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TentativeParsingAction Tentative(*this);
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ConsumeBracket();
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while (true) {
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switch (Tok.getKind()) {
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case tok::equal:
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case tok::amp:
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case tok::identifier:
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case tok::kw_this:
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// These tokens can occur in a capture list or a constant-expression.
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// Keep looking.
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ConsumeToken();
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continue;
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case tok::comma:
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// Since a comma cannot occur in a constant-expression, this must
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// be a lambda.
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Tentative.Revert();
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return false;
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case tok::r_square: {
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// Once we hit the closing square bracket, we look at the next
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// token. If it's an '=', this is a designator. Otherwise, it's a
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// lambda expression. This decision favors lambdas over the older
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// GNU designator syntax, which allows one to omit the '=', but is
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// consistent with GCC.
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ConsumeBracket();
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tok::TokenKind Kind = Tok.getKind();
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Tentative.Revert();
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return Kind == tok::equal;
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}
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default:
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// Anything else cannot occur in a lambda capture list, so it
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// must be a designator.
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Tentative.Revert();
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return true;
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}
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}
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return true;
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}
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static void CheckArrayDesignatorSyntax(Parser &P, SourceLocation Loc,
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Designation &Desig) {
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// If we have exactly one array designator, this used the GNU
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// 'designation: array-designator' extension, otherwise there should be no
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// designators at all!
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if (Desig.getNumDesignators() == 1 &&
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(Desig.getDesignator(0).isArrayDesignator() ||
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Desig.getDesignator(0).isArrayRangeDesignator()))
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P.Diag(Loc, diag::ext_gnu_missing_equal_designator);
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else if (Desig.getNumDesignators() > 0)
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P.Diag(Loc, diag::err_expected_equal_designator);
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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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ExprResult Parser::ParseInitializerWithPotentialDesignator() {
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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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const IdentifierInfo *FieldName = Tok.getIdentifierInfo();
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SmallString<256> NewSyntax;
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llvm::raw_svector_ostream(NewSyntax) << '.' << FieldName->getName()
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<< " = ";
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SourceLocation NameLoc = ConsumeToken(); // Eat the identifier.
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assert(Tok.is(tok::colon) && "MayBeDesignationStart not working properly!");
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SourceLocation ColonLoc = ConsumeToken();
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Diag(NameLoc, diag::ext_gnu_old_style_field_designator)
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<< FixItHint::CreateReplacement(SourceRange(NameLoc, ColonLoc),
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NewSyntax.str());
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Designation D;
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D.AddDesignator(Designator::getField(FieldName, SourceLocation(), NameLoc));
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return Actions.ActOnDesignatedInitializer(D, ColonLoc, true,
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ParseInitializer());
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}
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// Desig - This is initialized when we see our first designator. We may have
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// an objc message send with no designator, so we don't want to create this
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// eagerly.
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Designation Desig;
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// Parse each designator in the designator list until we find an initializer.
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while (Tok.is(tok::period) || Tok.is(tok::l_square)) {
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if (Tok.is(tok::period)) {
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// designator: '.' identifier
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SourceLocation DotLoc = ConsumeToken();
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if (Tok.isNot(tok::identifier)) {
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Diag(Tok.getLocation(), diag::err_expected_field_designator);
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return ExprError();
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}
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Desig.AddDesignator(Designator::getField(Tok.getIdentifierInfo(), DotLoc,
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Tok.getLocation()));
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ConsumeToken(); // Eat the identifier.
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continue;
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}
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// We must have either an array designator now or an objc message send.
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assert(Tok.is(tok::l_square) && "Unexpected token!");
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// Handle the two forms of array designator:
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// array-designator: '[' constant-expression ']'
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// array-designator: '[' constant-expression '...' constant-expression ']'
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//
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// Also, we have to handle the case where the expression after the
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// designator an an objc message send: '[' objc-message-expr ']'.
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// Interesting cases are:
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// [foo bar] -> objc message send
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// [foo] -> array designator
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// [foo ... bar] -> array designator
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// [4][foo bar] -> obsolete GNU designation with objc message send.
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//
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// We do not need to check for an expression starting with [[ here. If it
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// contains an Objective-C message send, then it is not an ill-formed
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// attribute. If it is a lambda-expression within an array-designator, then
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// it will be rejected because a constant-expression cannot begin with a
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// lambda-expression.
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InMessageExpressionRAIIObject InMessage(*this, true);
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BalancedDelimiterTracker T(*this, tok::l_square);
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T.consumeOpen();
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SourceLocation StartLoc = T.getOpenLocation();
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ExprResult Idx;
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// If Objective-C is enabled and this is a typename (class message
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// send) or send to 'super', parse this as a message send
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// expression. We handle C++ and C separately, since C++ requires
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// much more complicated parsing.
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if (getLangOpts().ObjC1 && getLangOpts().CPlusPlus) {
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// Send to 'super'.
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if (Tok.is(tok::identifier) && Tok.getIdentifierInfo() == Ident_super &&
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NextToken().isNot(tok::period) &&
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getCurScope()->isInObjcMethodScope()) {
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CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
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return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
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ConsumeToken(),
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ParsedType(),
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0);
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}
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// Parse the receiver, which is either a type or an expression.
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bool IsExpr;
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void *TypeOrExpr;
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if (ParseObjCXXMessageReceiver(IsExpr, TypeOrExpr)) {
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SkipUntil(tok::r_square, StopAtSemi);
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return ExprError();
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}
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// If the receiver was a type, we have a class message; parse
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// the rest of it.
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if (!IsExpr) {
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CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
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return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
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SourceLocation(),
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ParsedType::getFromOpaquePtr(TypeOrExpr),
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0);
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}
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// If the receiver was an expression, we still don't know
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// whether we have a message send or an array designator; just
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// adopt the expression for further analysis below.
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// FIXME: potentially-potentially evaluated expression above?
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Idx = ExprResult(static_cast<Expr*>(TypeOrExpr));
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} else if (getLangOpts().ObjC1 && Tok.is(tok::identifier)) {
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IdentifierInfo *II = Tok.getIdentifierInfo();
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SourceLocation IILoc = Tok.getLocation();
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ParsedType ReceiverType;
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// Three cases. This is a message send to a type: [type foo]
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// This is a message send to super: [super foo]
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// This is a message sent to an expr: [super.bar foo]
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switch (Sema::ObjCMessageKind Kind
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= Actions.getObjCMessageKind(getCurScope(), II, IILoc,
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II == Ident_super,
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NextToken().is(tok::period),
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ReceiverType)) {
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case Sema::ObjCSuperMessage:
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case Sema::ObjCClassMessage:
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CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
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if (Kind == Sema::ObjCSuperMessage)
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return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
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ConsumeToken(),
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ParsedType(),
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0);
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ConsumeToken(); // the identifier
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if (!ReceiverType) {
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SkipUntil(tok::r_square, StopAtSemi);
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return ExprError();
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}
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return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
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SourceLocation(),
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ReceiverType,
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0);
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case Sema::ObjCInstanceMessage:
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// Fall through; we'll just parse the expression and
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// (possibly) treat this like an Objective-C message send
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// later.
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break;
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}
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}
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// Parse the index expression, if we haven't already gotten one
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// above (which can only happen in Objective-C++).
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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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// FIXME: We also need to tell Sema that we're in a
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// potentially-potentially evaluated context.
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if (!Idx.get()) {
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Idx = ParseAssignmentExpression();
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if (Idx.isInvalid()) {
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SkipUntil(tok::r_square, StopAtSemi);
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return Idx;
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}
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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 (getLangOpts().ObjC1 && Tok.isNot(tok::ellipsis) &&
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Tok.isNot(tok::r_square)) {
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CheckArrayDesignatorSyntax(*this, Tok.getLocation(), Desig);
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return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
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SourceLocation(),
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ParsedType(),
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Idx.take());
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}
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// If this is a normal array designator, remember it.
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if (Tok.isNot(tok::ellipsis)) {
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Desig.AddDesignator(Designator::getArray(Idx.release(), StartLoc));
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} else {
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// Handle the gnu array range extension.
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Diag(Tok, diag::ext_gnu_array_range);
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SourceLocation EllipsisLoc = ConsumeToken();
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ExprResult RHS(ParseConstantExpression());
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if (RHS.isInvalid()) {
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SkipUntil(tok::r_square, StopAtSemi);
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return RHS;
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}
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Desig.AddDesignator(Designator::getArrayRange(Idx.release(),
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RHS.release(),
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StartLoc, EllipsisLoc));
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}
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T.consumeClose();
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Desig.getDesignator(Desig.getNumDesignators() - 1).setRBracketLoc(
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T.getCloseLocation());
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}
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// Okay, we're done with the designator sequence. We know that there must be
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// at least one designator, because the only case we can get into this method
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// without a designator is when we have an objc message send. That case is
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// handled and returned from above.
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assert(!Desig.empty() && "Designator is empty?");
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// Handle a normal designator sequence end, which is an equal.
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if (Tok.is(tok::equal)) {
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SourceLocation EqualLoc = ConsumeToken();
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return Actions.ActOnDesignatedInitializer(Desig, EqualLoc, false,
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ParseInitializer());
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}
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// We read some number of designators and found something that isn't an = or
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// an initializer. If we have exactly one array designator, this
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// is the GNU 'designation: array-designator' extension. Otherwise, it is a
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// parse error.
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if (Desig.getNumDesignators() == 1 &&
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(Desig.getDesignator(0).isArrayDesignator() ||
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Desig.getDesignator(0).isArrayRangeDesignator())) {
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Diag(Tok, diag::ext_gnu_missing_equal_designator)
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<< FixItHint::CreateInsertion(Tok.getLocation(), "= ");
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return Actions.ActOnDesignatedInitializer(Desig, Tok.getLocation(),
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true, ParseInitializer());
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}
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Diag(Tok, diag::err_expected_equal_designator);
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return ExprError();
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}
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/// ParseBraceInitializer - Called when parsing an initializer that has a
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/// leading open brace.
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///
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/// initializer: [C99 6.7.8]
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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 ...[opt]
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/// initializer-list ',' designation[opt] initializer ...[opt]
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///
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ExprResult Parser::ParseBraceInitializer() {
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InMessageExpressionRAIIObject InMessage(*this, false);
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BalancedDelimiterTracker T(*this, tok::l_brace);
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T.consumeOpen();
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SourceLocation LBraceLoc = T.getOpenLocation();
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/// InitExprs - This is the actual list of expressions contained in the
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/// initializer.
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ExprVector InitExprs;
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if (Tok.is(tok::r_brace)) {
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// Empty initializers are a C++ feature and a GNU extension to C.
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if (!getLangOpts().CPlusPlus)
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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, None, ConsumeBrace());
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}
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bool InitExprsOk = true;
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while (1) {
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// Handle Microsoft __if_exists/if_not_exists if necessary.
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if (getLangOpts().MicrosoftExt && (Tok.is(tok::kw___if_exists) ||
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Tok.is(tok::kw___if_not_exists))) {
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if (ParseMicrosoftIfExistsBraceInitializer(InitExprs, InitExprsOk)) {
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if (Tok.isNot(tok::comma)) break;
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ConsumeToken();
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}
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if (Tok.is(tok::r_brace)) break;
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continue;
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}
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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())
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SubElt = ParseInitializerWithPotentialDesignator();
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else
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SubElt = ParseInitializer();
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if (Tok.is(tok::ellipsis))
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SubElt = Actions.ActOnPackExpansion(SubElt.get(), ConsumeToken());
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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.release());
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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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// grammatically 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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// FIXME: This comment doesn't sound right. If there is a r_brace
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// immediately, it can't be an error, since there is no other way of
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// leaving this loop except through this if.
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if (Tok.isNot(tok::comma)) {
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SkipUntil(tok::r_brace, StopBeforeMatch);
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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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bool closed = !T.consumeClose();
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if (InitExprsOk && closed)
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return Actions.ActOnInitList(LBraceLoc, InitExprs,
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T.getCloseLocation());
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return ExprError(); // an error occurred.
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}
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// Return true if a comma (or closing brace) is necessary after the
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// __if_exists/if_not_exists statement.
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bool Parser::ParseMicrosoftIfExistsBraceInitializer(ExprVector &InitExprs,
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bool &InitExprsOk) {
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bool trailingComma = false;
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IfExistsCondition Result;
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if (ParseMicrosoftIfExistsCondition(Result))
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return false;
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BalancedDelimiterTracker Braces(*this, tok::l_brace);
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if (Braces.consumeOpen()) {
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Diag(Tok, diag::err_expected_lbrace);
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return false;
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}
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switch (Result.Behavior) {
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case IEB_Parse:
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// Parse the declarations below.
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break;
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case IEB_Dependent:
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Diag(Result.KeywordLoc, diag::warn_microsoft_dependent_exists)
|
||
<< Result.IsIfExists;
|
||
// Fall through to skip.
|
||
|
||
case IEB_Skip:
|
||
Braces.skipToEnd();
|
||
return false;
|
||
}
|
||
|
||
while (Tok.isNot(tok::eof)) {
|
||
trailingComma = false;
|
||
// If we know that this cannot be a designation, just parse the nested
|
||
// initializer directly.
|
||
ExprResult SubElt;
|
||
if (MayBeDesignationStart())
|
||
SubElt = ParseInitializerWithPotentialDesignator();
|
||
else
|
||
SubElt = ParseInitializer();
|
||
|
||
if (Tok.is(tok::ellipsis))
|
||
SubElt = Actions.ActOnPackExpansion(SubElt.get(), ConsumeToken());
|
||
|
||
// If we couldn't parse the subelement, bail out.
|
||
if (!SubElt.isInvalid())
|
||
InitExprs.push_back(SubElt.release());
|
||
else
|
||
InitExprsOk = false;
|
||
|
||
if (Tok.is(tok::comma)) {
|
||
ConsumeToken();
|
||
trailingComma = true;
|
||
}
|
||
|
||
if (Tok.is(tok::r_brace))
|
||
break;
|
||
}
|
||
|
||
Braces.consumeClose();
|
||
|
||
return !trailingComma;
|
||
}
|