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//===--- ParseInit.cpp - Initializer Parsing ------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and 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/Basic/Diagnostic.h"
#include "llvm/ADT/SmallString.h"
using namespace clang;
/// MayBeDesignationStart - Return true if this token might be the start of a
/// designator.
static bool MayBeDesignationStart(tok::TokenKind K) {
switch (K) {
default: return false;
case tok::period: // designator: '.' identifier
case tok::l_square: // designator: array-designator
case tok::identifier: // designation: identifier ':'
return true;
}
}
/// 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. We need to consider this case when parsing array designators.
///
Parser::ExprResult Parser::ParseInitializerWithPotentialDesignator() {
// Parse each designator in the designator list until we find an initializer.
while (1) {
switch (Tok.getKind()) {
case tok::equal:
// We read some number (at least one due to the grammar we implemented)
// of designators and found an '=' sign. The following tokens must be
// the initializer.
ConsumeToken();
return ParseInitializer();
default: {
// We read some number (at least one due to the grammar we implemented)
// of designators and found something that isn't an = or an initializer.
// If we have exactly one array designator [TODO CHECK], this is the GNU
// 'designation: array-designator' extension. Otherwise, it is a parse
// error.
SourceLocation Loc = Tok.getLocation();
ExprResult Init = ParseInitializer();
if (Init.isInvalid) return Init;
Diag(Tok, diag::ext_gnu_missing_equal_designator);
return Init;
}
case tok::period:
// designator: '.' identifier
ConsumeToken();
if (ExpectAndConsume(tok::identifier, diag::err_expected_ident))
return ExprResult(true);
break;
case tok::l_square: {
// array-designator: '[' constant-expression ']'
// array-designator: '[' constant-expression '...' constant-expression ']'
SourceLocation StartLoc = ConsumeBracket();
ExprResult Idx = ParseConstantExpression();
if (Idx.isInvalid) {
SkipUntil(tok::r_square);
return Idx;
}
// Handle the gnu array range extension.
if (Tok.getKind() == tok::ellipsis) {
Diag(Tok, diag::ext_gnu_array_range);
ConsumeToken();
ExprResult RHS = ParseConstantExpression();
if (RHS.isInvalid) {
SkipUntil(tok::r_square);
return RHS;
}
}
MatchRHSPunctuation(tok::r_square, StartLoc);
break;
}
case tok::identifier: {
// Due to the GNU "designation: identifier ':'" extension, we don't know
// whether something starting with an identifier is an
// assignment-expression or if it is an old-style structure field
// designator.
// TODO: Check that this is the first designator.
Token Ident = Tok;
ConsumeToken();
// If this is the gross GNU extension, handle it now.
if (Tok.getKind() == tok::colon) {
Diag(Ident, diag::ext_gnu_old_style_field_designator);
ConsumeToken();
return ParseInitializer();
}
// Otherwise, we just consumed the first token of an expression. Parse
// the rest of it now.
return ParseAssignmentExprWithLeadingIdentifier(Ident);
}
}
}
}
/// ParseInitializer
/// initializer: [C99 6.7.8]
/// assignment-expression
/// '{' initializer-list '}'
/// '{' initializer-list ',' '}'
/// [GNU] '{' '}'
///
/// initializer-list:
/// designation[opt] initializer
/// initializer-list ',' designation[opt] initializer
///
Parser::ExprResult Parser::ParseInitializer() {
if (Tok.getKind() != tok::l_brace)
return ParseAssignmentExpression();
SourceLocation LBraceLoc = ConsumeBrace();
// We support empty initializers, but tell the user that they aren't using
// C99-clean code.
if (Tok.getKind() == tok::r_brace) {
Diag(LBraceLoc, diag::ext_gnu_empty_initializer);
// Match the '}'.
return Actions.ActOnInitList(LBraceLoc, 0, 0, ConsumeBrace());
}
llvm::SmallVector<ExprTy*, 8> InitExprs;
bool InitExprsOk = true;
while (1) {
// Parse: designation[opt] initializer
// If we know that this cannot be a designation, just parse the nested
// initializer directly.
ExprResult SubElt;
if (!MayBeDesignationStart(Tok.getKind()))
SubElt = ParseInitializer();
else
SubElt = ParseInitializerWithPotentialDesignator();
// If we couldn't parse the subelement, bail out.
if (SubElt.isInvalid) {
InitExprsOk = false;
SkipUntil(tok::r_brace);
break;
} else
InitExprs.push_back(SubElt.Val);
// If we don't have a comma continued list, we're done.
if (Tok.getKind() != tok::comma) break;
// FIXME: save comma locations.
ConsumeToken();
// Handle trailing comma.
if (Tok.getKind() == tok::r_brace) break;
}
if (InitExprsOk && Tok.getKind() == tok::r_brace)
return Actions.ActOnInitList(LBraceLoc, &InitExprs[0], InitExprs.size(),
ConsumeBrace());
// Match the '}'.
MatchRHSPunctuation(tok::r_brace, LBraceLoc);
return ExprResult(true); // an error occurred.
}
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