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+//===--- ParseInit.cpp - Initializer Parsing ------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements initializer parsing as specified by C99 6.7.8.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Parse/Parser.h"
+#include "clang/Parse/ParseDiagnostic.h"
+#include "RAIIObjectsForParser.h"
+#include "clang/Sema/Designator.h"
+#include "clang/Sema/Scope.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace clang;
+
+
+/// MayBeDesignationStart - Return true if the current token might be the start
+/// of a designator. If we can tell it is impossible that it is a designator,
+/// return false.
+bool Parser::MayBeDesignationStart() {
+ switch (Tok.getKind()) {
+ default:
+ return false;
+
+ case tok::period: // designator: '.' identifier
+ return true;
+
+ case tok::l_square: { // designator: array-designator
+ if (!PP.getLangOpts().CPlusPlus0x)
+ return true;
+
+ // C++11 lambda expressions and C99 designators can be ambiguous all the
+ // way through the closing ']' and to the next character. Handle the easy
+ // cases here, and fall back to tentative parsing if those fail.
+ switch (PP.LookAhead(0).getKind()) {
+ case tok::equal:
+ case tok::r_square:
+ // Definitely starts a lambda expression.
+ return false;
+
+ case tok::amp:
+ case tok::kw_this:
+ case tok::identifier:
+ // We have to do additional analysis, because these could be the
+ // start of a constant expression or a lambda capture list.
+ break;
+
+ default:
+ // Anything not mentioned above cannot occur following a '[' in a
+ // lambda expression.
+ return true;
+ }
+
+ // Handle the complicated case below.
+ break;
+ }
+ case tok::identifier: // designation: identifier ':'
+ return PP.LookAhead(0).is(tok::colon);
+ }
+
+ // Parse up to (at most) the token after the closing ']' to determine
+ // whether this is a C99 designator or a lambda.
+ TentativeParsingAction Tentative(*this);
+ ConsumeBracket();
+ while (true) {
+ switch (Tok.getKind()) {
+ case tok::equal:
+ case tok::amp:
+ case tok::identifier:
+ case tok::kw_this:
+ // These tokens can occur in a capture list or a constant-expression.
+ // Keep looking.
+ ConsumeToken();
+ continue;
+
+ case tok::comma:
+ // Since a comma cannot occur in a constant-expression, this must
+ // be a lambda.
+ Tentative.Revert();
+ return false;
+
+ case tok::r_square: {
+ // Once we hit the closing square bracket, we look at the next
+ // token. If it's an '=', this is a designator. Otherwise, it's a
+ // lambda expression. This decision favors lambdas over the older
+ // GNU designator syntax, which allows one to omit the '=', but is
+ // consistent with GCC.
+ ConsumeBracket();
+ tok::TokenKind Kind = Tok.getKind();
+ Tentative.Revert();
+ return Kind == tok::equal;
+ }
+
+ default:
+ // Anything else cannot occur in a lambda capture list, so it
+ // must be a designator.
+ Tentative.Revert();
+ return true;
+ }
+ }
+
+ return true;
+}
+
+static void CheckArrayDesignatorSyntax(Parser &P, SourceLocation Loc,
+ Designation &Desig) {
+ // If we have exactly one array designator, this used the GNU
+ // 'designation: array-designator' extension, otherwise there should be no
+ // designators at all!
+ if (Desig.getNumDesignators() == 1 &&
+ (Desig.getDesignator(0).isArrayDesignator() ||
+ Desig.getDesignator(0).isArrayRangeDesignator()))
+ P.Diag(Loc, diag::ext_gnu_missing_equal_designator);
+ else if (Desig.getNumDesignators() > 0)
+ P.Diag(Loc, diag::err_expected_equal_designator);
+}
+
+/// ParseInitializerWithPotentialDesignator - Parse the 'initializer' production
+/// checking to see if the token stream starts with a designator.
+///
+/// designation:
+/// designator-list '='
+/// [GNU] array-designator
+/// [GNU] identifier ':'
+///
+/// designator-list:
+/// designator
+/// designator-list designator
+///
+/// designator:
+/// array-designator
+/// '.' identifier
+///
+/// array-designator:
+/// '[' constant-expression ']'
+/// [GNU] '[' constant-expression '...' constant-expression ']'
+///
+/// NOTE: [OBC] allows '[ objc-receiver objc-message-args ]' as an
+/// initializer (because it is an expression). We need to consider this case
+/// when parsing array designators.
+///
+ExprResult Parser::ParseInitializerWithPotentialDesignator() {
+
+ // If this is the old-style GNU extension:
+ // designation ::= identifier ':'
+ // Handle it as a field designator. Otherwise, this must be the start of a
+ // normal expression.
+ if (Tok.is(tok::identifier)) {
+ const IdentifierInfo *FieldName = Tok.getIdentifierInfo();
+
+ SmallString<256> NewSyntax;
+ llvm::raw_svector_ostream(NewSyntax) << '.' << FieldName->getName()
+ << " = ";
+
+ SourceLocation NameLoc = ConsumeToken(); // Eat the identifier.
+
+ assert(Tok.is(tok::colon) && "MayBeDesignationStart not working properly!");
+ SourceLocation ColonLoc = ConsumeToken();
+
+ Diag(NameLoc, diag::ext_gnu_old_style_field_designator)
+ << FixItHint::CreateReplacement(SourceRange(NameLoc, ColonLoc),
+ NewSyntax.str());
+
+ Designation D;
+ D.AddDesignator(Designator::getField(FieldName, SourceLocation(), NameLoc));
+ return Actions.ActOnDesignatedInitializer(D, ColonLoc, true,
+ ParseInitializer());
+ }
+
+ // Desig - This is initialized when we see our first designator. We may have
+ // an objc message send with no designator, so we don't want to create this
+ // eagerly.
+ Designation Desig;
+
+ // Parse each designator in the designator list until we find an initializer.
+ while (Tok.is(tok::period) || Tok.is(tok::l_square)) {
+ if (Tok.is(tok::period)) {
+ // designator: '.' identifier
+ SourceLocation DotLoc = ConsumeToken();
+
+ if (Tok.isNot(tok::identifier)) {
+ Diag(Tok.getLocation(), diag::err_expected_field_designator);
+ return ExprError();
+ }
+
+ Desig.AddDesignator(Designator::getField(Tok.getIdentifierInfo(), DotLoc,
+ Tok.getLocation()));
+ ConsumeToken(); // Eat the identifier.
+ continue;
+ }
+
+ // We must have either an array designator now or an objc message send.
+ assert(Tok.is(tok::l_square) && "Unexpected token!");
+
+ // Handle the two forms of array designator:
+ // array-designator: '[' constant-expression ']'
+ // array-designator: '[' constant-expression '...' constant-expression ']'
+ //
+ // Also, we have to handle the case where the expression after the
+ // designator an an objc message send: '[' objc-message-expr ']'.
+ // Interesting cases are:
+ // [foo bar] -> objc message send
+ // [foo] -> array designator
+ // [foo ... bar] -> array designator
+ // [4][foo bar] -> obsolete GNU designation with objc message send.
+ //
+ // We do not need to check for an expression starting with [[ here. If it
+ // contains an Objective-C message send, then it is not an ill-formed
+ // attribute. If it is a lambda-expression within an array-designator, then
+ // it will be rejected because a constant-expression cannot begin with a
+ // lambda-expression.
+ InMessageExpressionRAIIObject InMessage(*this, true);
+
+ BalancedDelimiterTracker T(*this, tok::l_square);
+ T.consumeOpen();
+ SourceLocation StartLoc = T.getOpenLocation();
+
+ ExprResult Idx;
+
+ // If Objective-C is enabled and this is a typename (class message
+ // send) or send to 'super', parse this as a message send
+ // expression. We handle C++ and C separately, since C++ requires
+ // much more complicated parsing.
+ if (getLangOpts().ObjC1 && getLangOpts().CPlusPlus) {
+ // Send to 'super'.
+ if (Tok.is(tok::identifier) && Tok.getIdentifierInfo() == Ident_super &&
+ NextToken().isNot(tok::period) &&
+ getCurScope()->isInObjcMethodScope()) {
+ CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
+ return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
+ ConsumeToken(),
+ ParsedType(),
+ 0);
+ }
+
+ // Parse the receiver, which is either a type or an expression.
+ bool IsExpr;
+ void *TypeOrExpr;
+ if (ParseObjCXXMessageReceiver(IsExpr, TypeOrExpr)) {
+ SkipUntil(tok::r_square);
+ return ExprError();
+ }
+
+ // If the receiver was a type, we have a class message; parse
+ // the rest of it.
+ if (!IsExpr) {
+ CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
+ return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
+ SourceLocation(),
+ ParsedType::getFromOpaquePtr(TypeOrExpr),
+ 0);
+ }
+
+ // If the receiver was an expression, we still don't know
+ // whether we have a message send or an array designator; just
+ // adopt the expression for further analysis below.
+ // FIXME: potentially-potentially evaluated expression above?
+ Idx = ExprResult(static_cast<Expr*>(TypeOrExpr));
+ } else if (getLangOpts().ObjC1 && Tok.is(tok::identifier)) {
+ IdentifierInfo *II = Tok.getIdentifierInfo();
+ SourceLocation IILoc = Tok.getLocation();
+ ParsedType ReceiverType;
+ // Three cases. This is a message send to a type: [type foo]
+ // This is a message send to super: [super foo]
+ // This is a message sent to an expr: [super.bar foo]
+ switch (Sema::ObjCMessageKind Kind
+ = Actions.getObjCMessageKind(getCurScope(), II, IILoc,
+ II == Ident_super,
+ NextToken().is(tok::period),
+ ReceiverType)) {
+ case Sema::ObjCSuperMessage:
+ case Sema::ObjCClassMessage:
+ CheckArrayDesignatorSyntax(*this, StartLoc, Desig);
+ if (Kind == Sema::ObjCSuperMessage)
+ return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
+ ConsumeToken(),
+ ParsedType(),
+ 0);
+ ConsumeToken(); // the identifier
+ if (!ReceiverType) {
+ SkipUntil(tok::r_square);
+ return ExprError();
+ }
+
+ return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
+ SourceLocation(),
+ ReceiverType,
+ 0);
+
+ case Sema::ObjCInstanceMessage:
+ // Fall through; we'll just parse the expression and
+ // (possibly) treat this like an Objective-C message send
+ // later.
+ break;
+ }
+ }
+
+ // Parse the index expression, if we haven't already gotten one
+ // above (which can only happen in Objective-C++).
+ // Note that we parse this as an assignment expression, not a constant
+ // expression (allowing *=, =, etc) to handle the objc case. Sema needs
+ // to validate that the expression is a constant.
+ // FIXME: We also need to tell Sema that we're in a
+ // potentially-potentially evaluated context.
+ if (!Idx.get()) {
+ Idx = ParseAssignmentExpression();
+ if (Idx.isInvalid()) {
+ SkipUntil(tok::r_square);
+ return move(Idx);
+ }
+ }
+
+ // Given an expression, we could either have a designator (if the next
+ // tokens are '...' or ']' or an objc message send. If this is an objc
+ // message send, handle it now. An objc-message send is the start of
+ // an assignment-expression production.
+ if (getLangOpts().ObjC1 && Tok.isNot(tok::ellipsis) &&
+ Tok.isNot(tok::r_square)) {
+ CheckArrayDesignatorSyntax(*this, Tok.getLocation(), Desig);
+ return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
+ SourceLocation(),
+ ParsedType(),
+ Idx.take());
+ }
+
+ // If this is a normal array designator, remember it.
+ if (Tok.isNot(tok::ellipsis)) {
+ Desig.AddDesignator(Designator::getArray(Idx.release(), StartLoc));
+ } else {
+ // Handle the gnu array range extension.
+ Diag(Tok, diag::ext_gnu_array_range);
+ SourceLocation EllipsisLoc = ConsumeToken();
+
+ ExprResult RHS(ParseConstantExpression());
+ if (RHS.isInvalid()) {
+ SkipUntil(tok::r_square);
+ return move(RHS);
+ }
+ Desig.AddDesignator(Designator::getArrayRange(Idx.release(),
+ RHS.release(),
+ StartLoc, EllipsisLoc));
+ }
+
+ T.consumeClose();
+ Desig.getDesignator(Desig.getNumDesignators() - 1).setRBracketLoc(
+ T.getCloseLocation());
+ }
+
+ // Okay, we're done with the designator sequence. We know that there must be
+ // at least one designator, because the only case we can get into this method
+ // without a designator is when we have an objc message send. That case is
+ // handled and returned from above.
+ assert(!Desig.empty() && "Designator is empty?");
+
+ // Handle a normal designator sequence end, which is an equal.
+ if (Tok.is(tok::equal)) {
+ SourceLocation EqualLoc = ConsumeToken();
+ return Actions.ActOnDesignatedInitializer(Desig, EqualLoc, false,
+ ParseInitializer());
+ }
+
+ // We read some number of designators and found something that isn't an = or
+ // an initializer. If we have exactly one array designator, this
+ // is the GNU 'designation: array-designator' extension. Otherwise, it is a
+ // parse error.
+ if (Desig.getNumDesignators() == 1 &&
+ (Desig.getDesignator(0).isArrayDesignator() ||
+ Desig.getDesignator(0).isArrayRangeDesignator())) {
+ Diag(Tok, diag::ext_gnu_missing_equal_designator)
+ << FixItHint::CreateInsertion(Tok.getLocation(), "= ");
+ return Actions.ActOnDesignatedInitializer(Desig, Tok.getLocation(),
+ true, ParseInitializer());
+ }
+
+ Diag(Tok, diag::err_expected_equal_designator);
+ return ExprError();
+}
+
+
+/// ParseBraceInitializer - Called when parsing an initializer that has a
+/// leading open brace.
+///
+/// initializer: [C99 6.7.8]
+/// '{' initializer-list '}'
+/// '{' initializer-list ',' '}'
+/// [GNU] '{' '}'
+///
+/// initializer-list:
+/// designation[opt] initializer ...[opt]
+/// initializer-list ',' designation[opt] initializer ...[opt]
+///
+ExprResult Parser::ParseBraceInitializer() {
+ InMessageExpressionRAIIObject InMessage(*this, false);
+
+ BalancedDelimiterTracker T(*this, tok::l_brace);
+ T.consumeOpen();
+ SourceLocation LBraceLoc = T.getOpenLocation();
+
+ /// InitExprs - This is the actual list of expressions contained in the
+ /// initializer.
+ ExprVector InitExprs(Actions);
+
+ if (Tok.is(tok::r_brace)) {
+ // Empty initializers are a C++ feature and a GNU extension to C.
+ if (!getLangOpts().CPlusPlus)
+ Diag(LBraceLoc, diag::ext_gnu_empty_initializer);
+ // Match the '}'.
+ return Actions.ActOnInitList(LBraceLoc, MultiExprArg(Actions),
+ ConsumeBrace());
+ }
+
+ bool InitExprsOk = true;
+
+ while (1) {
+ // Handle Microsoft __if_exists/if_not_exists if necessary.
+ if (getLangOpts().MicrosoftExt && (Tok.is(tok::kw___if_exists) ||
+ Tok.is(tok::kw___if_not_exists))) {
+ if (ParseMicrosoftIfExistsBraceInitializer(InitExprs, InitExprsOk)) {
+ if (Tok.isNot(tok::comma)) break;
+ ConsumeToken();
+ }
+ if (Tok.is(tok::r_brace)) break;
+ continue;
+ }
+
+ // Parse: designation[opt] initializer
+
+ // 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;
+
+ // We have two ways to try to recover from this error: if the code looks
+ // grammatically ok (i.e. we have a comma coming up) try to continue
+ // parsing the rest of the initializer. This allows us to emit
+ // diagnostics for later elements that we find. If we don't see a comma,
+ // assume there is a parse error, and just skip to recover.
+ // FIXME: This comment doesn't sound right. If there is a r_brace
+ // immediately, it can't be an error, since there is no other way of
+ // leaving this loop except through this if.
+ if (Tok.isNot(tok::comma)) {
+ SkipUntil(tok::r_brace, false, true);
+ break;
+ }
+ }
+
+ // If we don't have a comma continued list, we're done.
+ if (Tok.isNot(tok::comma)) break;
+
+ // TODO: save comma locations if some client cares.
+ ConsumeToken();
+
+ // Handle trailing comma.
+ if (Tok.is(tok::r_brace)) break;
+ }
+
+ bool closed = !T.consumeClose();
+
+ if (InitExprsOk && closed)
+ return Actions.ActOnInitList(LBraceLoc, move_arg(InitExprs),
+ T.getCloseLocation());
+
+ return ExprError(); // an error occurred.
+}
+
+
+// Return true if a comma (or closing brace) is necessary after the
+// __if_exists/if_not_exists statement.
+bool Parser::ParseMicrosoftIfExistsBraceInitializer(ExprVector &InitExprs,
+ bool &InitExprsOk) {
+ bool trailingComma = false;
+ IfExistsCondition Result;
+ if (ParseMicrosoftIfExistsCondition(Result))
+ return false;
+
+ BalancedDelimiterTracker Braces(*this, tok::l_brace);
+ if (Braces.consumeOpen()) {
+ Diag(Tok, diag::err_expected_lbrace);
+ return false;
+ }
+
+ switch (Result.Behavior) {
+ case IEB_Parse:
+ // Parse the declarations below.
+ break;
+
+ case IEB_Dependent:
+ 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;
+}
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