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designated initializers. This implementation should cover all of the constraints in C99 6.7.8, including long, complex designations and computing the size of incomplete array types initialized with a designated initializer. Please see the new test-case and holler if you find cases where this doesn't work. There are still some wrinkles with GNU's anonymous structs and anonymous unions (it isn't clear how these should work; we'll just follow GCC's lead) and with designated initializers for the members of a union. I'll tackle those very soon. CodeGen is still nonexistent, and there's some leftover code in the parser's representation of designators that I'll also need to clean up. llvm-svn: 62737
328 lines
12 KiB
C++
328 lines
12 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 "AstGuard.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, Preprocessor &PP) {
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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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return true;
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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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}
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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::OwningExprResult 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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Diag(Tok, diag::ext_gnu_old_style_field_designator);
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const IdentifierInfo *FieldName = Tok.getIdentifierInfo();
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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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Designation &D = Designations.CreateDesignation(InitNum);
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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 = 0;
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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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// Create designation if we haven't already.
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if (Desig == 0)
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Desig = &Designations.CreateDesignation(InitNum);
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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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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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// 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) {
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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(StartLoc, diag::ext_gnu_missing_equal_designator);
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else
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Diag(Tok, diag::err_expected_equal_designator);
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}
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IdentifierInfo *Name = Tok.getIdentifierInfo();
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SourceLocation NameLoc = ConsumeToken();
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return ParseAssignmentExprWithObjCMessageExprStart(
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StartLoc, NameLoc, Name, ExprArg(Actions));
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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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OwningExprResult Idx(ParseAssignmentExpression());
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if (Idx.isInvalid()) {
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SkipUntil(tok::r_square);
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return move(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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// 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) {
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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(StartLoc, diag::ext_gnu_missing_equal_designator);
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else
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Diag(Tok, diag::err_expected_equal_designator);
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}
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return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
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SourceLocation(),
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0, move_arg(Idx));
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}
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// Create designation if we haven't already.
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if (Desig == 0)
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Desig = &Designations.CreateDesignation(InitNum);
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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(),
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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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OwningExprResult RHS(ParseConstantExpression());
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if (RHS.isInvalid()) {
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SkipUntil(tok::r_square);
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return move(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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SourceLocation EndLoc = MatchRHSPunctuation(tok::r_square, StartLoc);
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Desig->getDesignator(Desig->getNumDesignators() - 1).setRBracketLoc(EndLoc);
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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 && "Designator didn't get created?");
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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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return 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
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/// initializer-list ',' designation[opt] initializer
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///
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Parser::OwningExprResult Parser::ParseBraceInitializer() {
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SourceLocation LBraceLoc = ConsumeBrace();
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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(Actions);
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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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// 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, Action::MultiExprArg(Actions),
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InitExprDesignations, ConsumeBrace());
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}
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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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OwningExprResult SubElt(Actions);
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if (!MayBeDesignationStart(Tok.getKind(), PP))
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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 had an erroneous initializer, and we had a potentially valid
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// designator, make sure to remove the designator from
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// InitExprDesignations, otherwise we'll end up with a designator with no
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// matching initializer.
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if (SubElt.isInvalid())
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InitExprDesignations.EraseDesignation(InitExprs.size());
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}
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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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// 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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// 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, 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, move_arg(InitExprs),
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InitExprDesignations, ConsumeBrace());
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// Match the '}'.
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MatchRHSPunctuation(tok::r_brace, LBraceLoc);
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return ExprError(); // an error occurred.
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}
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