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Diffstat (limited to 'lib/Parse/ParseInit.cpp')
| -rw-r--r-- | lib/Parse/ParseInit.cpp | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/lib/Parse/ParseInit.cpp b/lib/Parse/ParseInit.cpp new file mode 100644 index 0000000..bbc2124 --- /dev/null +++ b/lib/Parse/ParseInit.cpp @@ -0,0 +1,308 @@ +//===--- 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/Designator.h" +#include "clang/Parse/Parser.h" +#include "clang/Parse/ParseDiagnostic.h" +#include "llvm/ADT/SmallString.h" +using namespace clang; + + +/// MayBeDesignationStart - Return true if this token might be the start of a +/// designator. If we can tell it is impossible that it is a designator, return +/// false. +static bool MayBeDesignationStart(tok::TokenKind K, Preprocessor &PP) { + switch (K) { + default: return false; + case tok::period: // designator: '.' identifier + case tok::l_square: // designator: array-designator + return true; + case tok::identifier: // designation: identifier ':' + return PP.LookAhead(0).is(tok::colon); + } +} + +/// 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. +/// +Parser::OwningExprResult 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(); + + std::string NewSyntax("."); + NewSyntax += FieldName->getName(); + NewSyntax += " = "; + + SourceLocation NameLoc = ConsumeToken(); // Eat the identifier. + + assert(Tok.is(tok::colon) && "MayBeDesignationStart not working properly!"); + SourceLocation ColonLoc = ConsumeToken(); + + Diag(Tok, diag::ext_gnu_old_style_field_designator) + << CodeModificationHint::CreateReplacement(SourceRange(NameLoc, + ColonLoc), + NewSyntax); + + 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. + // + SourceLocation StartLoc = ConsumeBracket(); + + // If Objective-C is enabled and this is a typename or other identifier + // receiver, parse this as a message send expression. + if (getLang().ObjC1 && isTokObjCMessageIdentifierReceiver()) { + // 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())) + Diag(StartLoc, diag::ext_gnu_missing_equal_designator); + else if (Desig.getNumDesignators() > 0) + Diag(Tok, diag::err_expected_equal_designator); + + IdentifierInfo *Name = Tok.getIdentifierInfo(); + SourceLocation NameLoc = ConsumeToken(); + return ParseAssignmentExprWithObjCMessageExprStart( + StartLoc, NameLoc, Name, ExprArg(Actions)); + } + + // 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. + OwningExprResult 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 (getLang().ObjC1 && Tok.isNot(tok::ellipsis) && + Tok.isNot(tok::r_square)) { + + // 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())) + Diag(StartLoc, diag::ext_gnu_missing_equal_designator); + else if (Desig.getNumDesignators() > 0) + Diag(Tok, diag::err_expected_equal_designator); + + return ParseAssignmentExprWithObjCMessageExprStart(StartLoc, + SourceLocation(), + 0, move(Idx)); + } + + // 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(); + + OwningExprResult RHS(ParseConstantExpression()); + if (RHS.isInvalid()) { + SkipUntil(tok::r_square); + return move(RHS); + } + Desig.AddDesignator(Designator::getArrayRange(Idx.release(), + RHS.release(), + StartLoc, EllipsisLoc)); + } + + SourceLocation EndLoc = MatchRHSPunctuation(tok::r_square, StartLoc); + Desig.getDesignator(Desig.getNumDesignators() - 1).setRBracketLoc(EndLoc); + } + + // 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) + << CodeModificationHint::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 +/// initializer-list ',' designation[opt] initializer +/// +Parser::OwningExprResult Parser::ParseBraceInitializer() { + SourceLocation LBraceLoc = ConsumeBrace(); + + /// 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 (!getLang().CPlusPlus) + Diag(LBraceLoc, diag::ext_gnu_empty_initializer); + // Match the '}'. + return Actions.ActOnInitList(LBraceLoc, Action::MultiExprArg(Actions), + ConsumeBrace()); + } + + bool InitExprsOk = true; + + while (1) { + // Parse: designation[opt] initializer + + // If we know that this cannot be a designation, just parse the nested + // initializer directly. + OwningExprResult SubElt(Actions); + if (MayBeDesignationStart(Tok.getKind(), PP)) + SubElt = ParseInitializerWithPotentialDesignator(); + else + SubElt = ParseInitializer(); + + // 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 + // gramatically 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; + } + if (InitExprsOk && Tok.is(tok::r_brace)) + return Actions.ActOnInitList(LBraceLoc, move_arg(InitExprs), + ConsumeBrace()); + + // Match the '}'. + MatchRHSPunctuation(tok::r_brace, LBraceLoc); + return ExprError(); // an error occurred. +} + |
