lib/Parse/ParseInit.cpp - platform/external/clang - Gitiles

 //===--- 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 "AstGuard.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.  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(InitListDesignations &Designations,
                                         unsigned InitNum) {

   // 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)) {
     Diag(Tok, diag::ext_gnu_old_style_field_designator);

     const IdentifierInfo *FieldName = Tok.getIdentifierInfo();
     SourceLocation NameLoc = ConsumeToken(); // Eat the identifier.

     assert(Tok.is(tok::colon) && "MayBeDesignationStart not working properly!");
     SourceLocation ColonLoc = ConsumeToken();

     Designation &D = Designations.CreateDesignation(InitNum);
     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 = 0;

   // 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();

       // Create designation if we haven't already.
       if (Desig == 0)
         Desig = &Designations.CreateDesignation(InitNum);

       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) {
         if (Desig->getNumDesignators() == 1 &&
             (Desig->getDesignator(0).isArrayDesignator() ||
              Desig->getDesignator(0).isArrayRangeDesignator()))
           Diag(StartLoc, diag::ext_gnu_missing_equal_designator);
         else
           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) {
         if (Desig->getNumDesignators() == 1 &&
             (Desig->getDesignator(0).isArrayDesignator() ||
              Desig->getDesignator(0).isArrayRangeDesignator()))
           Diag(StartLoc, diag::ext_gnu_missing_equal_designator);
         else
           Diag(Tok, diag::err_expected_equal_designator);
       }

       return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
                                                          SourceLocation(),
                                                          0, move_arg(Idx));
     }

     // Create designation if we haven't already.
     if (Desig == 0)
       Desig = &Designations.CreateDesignation(InitNum);

     // 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 && "Designator didn't get created?");

   // 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);
     return 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);

   /// ExprDesignators - For each initializer, keep track of the designator that
   /// was specified for it, if any.
   InitListDesignations InitExprDesignations(Actions);

   // We support empty initializers, but tell the user that they aren't using
   // C99-clean code.
   if (Tok.is(tok::r_brace)) {
     Diag(LBraceLoc, diag::ext_gnu_empty_initializer);
     // Match the '}'.
     return Actions.ActOnInitList(LBraceLoc, Action::MultiExprArg(Actions),
                                  InitExprDesignations, 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 = ParseInitializer();
     else {
       SubElt = ParseInitializerWithPotentialDesignator(InitExprDesignations,
                                                        InitExprs.size());

       // If we had an erroneous initializer, and we had a potentially valid
       // designator, make sure to remove the designator from
       // InitExprDesignations, otherwise we'll end up with a designator with no
       // matching initializer.
       if (SubElt.isInvalid())
         InitExprDesignations.EraseDesignation(InitExprs.size());
     }

     // 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),
                                  InitExprDesignations, ConsumeBrace());

   // Match the '}'.
   MatchRHSPunctuation(tok::r_brace, LBraceLoc);
   return ExprError(); // an error occurred.
 }
	//===--- 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 "AstGuard.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. 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(InitListDesignations &Designations,
	unsigned InitNum) {

	// 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)) {
	Diag(Tok, diag::ext_gnu_old_style_field_designator);

	const IdentifierInfo *FieldName = Tok.getIdentifierInfo();
	SourceLocation NameLoc = ConsumeToken(); // Eat the identifier.

	assert(Tok.is(tok::colon) && "MayBeDesignationStart not working properly!");
	SourceLocation ColonLoc = ConsumeToken();

	Designation &D = Designations.CreateDesignation(InitNum);
	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 = 0;

	// 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();

	// Create designation if we haven't already.
	if (Desig == 0)
	Desig = &Designations.CreateDesignation(InitNum);

	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) {
	if (Desig->getNumDesignators() == 1 &&
	(Desig->getDesignator(0).isArrayDesignator() \|\|
	Desig->getDesignator(0).isArrayRangeDesignator()))
	Diag(StartLoc, diag::ext_gnu_missing_equal_designator);
	else
	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) {
	if (Desig->getNumDesignators() == 1 &&
	(Desig->getDesignator(0).isArrayDesignator() \|\|
	Desig->getDesignator(0).isArrayRangeDesignator()))
	Diag(StartLoc, diag::ext_gnu_missing_equal_designator);
	else
	Diag(Tok, diag::err_expected_equal_designator);
	}

	return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
	SourceLocation(),
	0, move_arg(Idx));
	}

	// Create designation if we haven't already.
	if (Desig == 0)
	Desig = &Designations.CreateDesignation(InitNum);

	// 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 && "Designator didn't get created?");

	// 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);
	return 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);

	/// ExprDesignators - For each initializer, keep track of the designator that
	/// was specified for it, if any.
	InitListDesignations InitExprDesignations(Actions);

	// We support empty initializers, but tell the user that they aren't using
	// C99-clean code.
	if (Tok.is(tok::r_brace)) {
	Diag(LBraceLoc, diag::ext_gnu_empty_initializer);
	// Match the '}'.
	return Actions.ActOnInitList(LBraceLoc, Action::MultiExprArg(Actions),
	InitExprDesignations, 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 = ParseInitializer();
	else {
	SubElt = ParseInitializerWithPotentialDesignator(InitExprDesignations,
	InitExprs.size());

	// If we had an erroneous initializer, and we had a potentially valid
	// designator, make sure to remove the designator from
	// InitExprDesignations, otherwise we'll end up with a designator with no
	// matching initializer.
	if (SubElt.isInvalid())
	InitExprDesignations.EraseDesignation(InitExprs.size());
	}

	// 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),
	InitExprDesignations, ConsumeBrace());

	// Match the '}'.
	MatchRHSPunctuation(tok::r_brace, LBraceLoc);
	return ExprError(); // an error occurred.
	}