// gnu.gr            see license.txt for copyright and terms of use
// extension to cc.gr for GNU C/C++ language extensions

// NOTE: Though the name of this module is "gnu.gr", in fact we also
// put our C99 support here.  For the moment, it isn't worth it to
// split out C99 from GNU, because our usage model is that either you
// want to parse ANSI C++, or you want to parse whatever gcc/g++
// accepts.  The "gnu" extensions (try to) provide the latter.  (Also,
// there are a few extensions like "long long" that are provided by
// both, so the split wouldn't be 100% clean.)
//
// 9/27/04: The current concept is that gnu.gr contains the syntactic
// extensions included in the modern, extended C++ language,
// especially as used on linux.  It does *not* include old K&R syntax,
// which will be put in kandr.gr.
//
// Specifically, the extensions found in this file are:
//   - gcc statement expression: "({ ... })"
//   - gcc compound literals: "(struct Foo){ ... }"
//   - gcc misc: __alignof__, etc.
//   - gcc dangling labels: "{ ... foo: }"
//   - gcc typeof
//   - gcc C++ min and max operators ">?" and "<?"
//   - gcc asm with register constraints, etc.
//   - gcc asm labels: "int foo asm("myfoo") = 2"
//   - C99 designated initializers: "... = { .x=..., .y=... }"
//     including gcc range extension: "[ 1 ... 3 ] = ..."
//   - C99 restrict keyword
//   - C99 qualifiers in array brackets: "[const ...]"
//   - gcc __attribute__
//   - gcc bug: typedef names + type modifiers: "u32 long"
//   - gcc computed gotos
//   - gcc/C99 complex/imaginary


// expected statistics
option shift_reduce_conflicts 87;
option reduce_reduce_conflicts 86;


terminals {
  precedence {
    // see note at end regarding implementation of __attribute__
    prec  190 "__attribute__" "restrict";

    // the experimentation I did in in/gnu/g0019.cc suggests that
    // these operators have the same prec/assoc as "<" and ">"
    //left   80 "<?" ">?";
  }
}


// ----------- gcc statement expression -----------
// http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Statement-Exprs.html
nonterm(Expression*) PrimaryExpression {
  -> "(" cs:CompoundStatement ")"
       { return new E_statement(loc ENDLOCARG(endloc), cs); }
}


// ----------- gcc compound literals -----------
// http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Compound-Literals.html
// (notation for literal struct values)
// e.g.:
//   struct Foo { int x; int y; } myfoo;
//   myfoo = (struct Foo) { 4, 5 };        <-- here
// which would assign x=4 and y=5 in 'myfoo'
nonterm(Expression*) PrimaryExpression {
  -> "(" t:TypeId ")" i:CompoundInitializer
       { return new E_compoundLit(loc ENDLOCARG(endloc), t, i); }
}


// ----------- gcc misc -----------

// dmandelin@mozilla.com
// These are like function calls; they should have the same nonterminal
nonterm(Expression*) PostfixExpression {
  // GNU extension; dsw: Since the argument is an expression, I know
  // of no way to handle this other than putting it into the grammar
  // directly.
  -> "__builtin_constant_p" pe:ParenthesizedExpression
       { return new E___builtin_constant_p(loc ENDLOCARG(endloc), pe); }

  // http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Alignment.html
  -> "__alignof__" "(" t:TypeId ")"
       { return new E_alignofType(loc ENDLOCARG(endloc), t); }
  -> "__alignof__" "(" e:Expression ")"
       { return new E_alignofExpr(loc ENDLOCARG(endloc), e); }

  // quarl 2006-07-12
  //    Handle __offsetof__ (gcc-3.4), __builtin_offsetof (gcc-4.x)
  -> "__builtin_offsetof" "(" t:TypeId "," n:NamesAfterDot ")"
       // { return new E_offsetof(loc ENDLOCARG(endloc), t, n); }
       {
         // just create "(unsigned long) &((t*)0)->n)"

         // Create the ASTTypeId to represent the pointer-to-t
         // dmandelin@mozilla.com -- Need to clone the type before modifying.
         // Otherwise, the mod can get run more than once when in an ambiguous
	 // context, which would make t be pointer-to-pointer-to-t.
         t = t->clone();
         t->decl->decl = new D_pointer(loc, endloc, CV_NONE, t->decl->decl);

         ASTTypeId *ulong = new ASTTypeId(new TS_simple(loc, endloc, ST_UNSIGNED_INT),
                                          new Declarator(new D_name(loc, endloc, NULL), NULL));


	 // dmandelin@mozilla.com   bug 416051
         Expression *einner = n;
	 while (E_fieldAcc *fa = einner->ifE_fieldAcc()) {
	     einner = fa->obj;
         }
	 E_arrow *inner = einner->asE_arrow();
         inner->loc = loc;
         inner->endloc = endloc;
         inner->obj = new E_cast(loc ENDLOCARG(endloc), t,
                                 new E_intLit(loc ENDLOCARG(endloc), "0"));
         return new E_cast(loc ENDLOCARG(endloc), ulong,
                           (new E_addrOf(loc ENDLOCARG(endloc), n)));
       }

  -> "__offsetof__" "(" e:Expression ")"
       { return new E_grouping(loc ENDLOCARG(endloc), e); }

  // sm: __builtin_expect is for static branch prediction, but none of
  // the analyses I forsee for this parser care about such things, so
  // I will simply pretend I never even saw it (though, this is a
  // small problem for source to source ...); the alternative is to make
  // a new AST node for it, or else squeeze it into E_funCall, neither of
  // which is very attractive
  //
  // A third possibility is a new "semantically transparent but
  // annotated in some way" AST node, of which __builtin_expect could
  // be one kind.  I'm not sure what other kinds there would be,
  // though.
  -> "__builtin_expect" "(" e:Expression "," /*prediction*/Expression ")"
       { return new E_grouping(loc ENDLOCARG(endloc), e); }

  // varargs; dsw: I think that we should make all of these their own
  // AST node, I just don't want to deal with the parsing ambiguity
  // with E_funCall right now
  // rdp: I'll give it a try.
  -> "__builtin_va_start" "(" e:Expression "," e2:Expression ")"
       { return new E___builtin_va_start(loc ENDLOCARG(endloc), e, e2); }
  -> "__builtin_va_copy" "(" e:Expression "," e2:Expression ")"
       { return new E___builtin_va_copy(loc ENDLOCARG(endloc), e, e2); }
  -> "__builtin_va_arg" "(" e:Expression "," t:TypeId ")"
       { return new E___builtin_va_arg(loc ENDLOCARG(endloc), e, t); }
  -> "__builtin_va_end" "(" e:Expression ")"
        { return new E___builtin_va_end(loc ENDLOCARG(endloc), e); }

  -> "__builtin_alloca" "(" e:Expression ")"
        { return new E___builtin_alloca(loc ENDLOCARG(endloc), e); }
}

// dmandelin@mozilla.com  bug 416051
// Represents something that can appear as arg2 of the builtin offsetof
// operator in gcc. This will be used to make an expression of the form
//    ((A*) NULL)->a.b
// so we construct the right-hand part of that expression here, and let
// the context fill in the cast and NULL in the offsetof action.
nonterm(Expression*) NamesAfterDot {
  -> n:NameAfterDot
       { return new E_arrow(loc ENDLOCARG(endloc), NULL, n); }
  -> n:NamesAfterDot "." n2:NameAfterDot
       { return new E_fieldAcc(loc ENDLOCARG(endloc), n, n2); }
}

// dsw: had to break this out for location recording reasons
nonterm(Expression*) ParenthesizedExpression {
  -> "(" e:Expression ")"
       { return new E_grouping(loc ENDLOCARG(endloc), e); }
}


// http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Conditionals.html
nonterm(Expression*) ConditionalExpression {
  -> cond:BinaryExpression "?" /*th:Expression*/ ":" el:AssignmentExpression
       { return new E_gnuCond(loc ENDLOCARG(endloc), cond, el); }
}


// http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Nested-Functions.html
nonterm(Statement*) Statement {
  -> f:FunctionDefinition
       { return new S_function(loc ENDLOCARG(endloc), f); }
  // quarl 2006-06-15
  //    nested K&R functions; unimplemented for now but I guess we just need
  //    to do the same as above?  see in/gnu/k0010.c
  -> k:KandRFunctionDefinition
       { xunimp(stringc << loc << "nested K&R function definition"
                " (d00aa531-ca12-4d72-9caf-ca9db9941179)"); }
}


// http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Template-Instantiation.html
nonterm(TopForm*) ExplicitInstantiation {
  // here's one for things like (in/gnu/g0002.cc)
  //   extern template class allocator<char>;
  -> "extern" "template" d:BlockDeclaration
       { return new TF_explicitInst(loc, DF_EXTERN, d); }
}


// http://gcc.gnu.org/onlinedocs/gcc-3.4.1/gcc/Case-Ranges.html
nonterm(Statement*) Statement {
  -> "case" e:ConstantExpression "..." e2:ConstantExpression ":" s:Statement
       { return new S_rangeCase(loc ENDLOCARG(endloc), e, e2, s); }
}


// ----------- gcc dangling labels -----------
// gcc allows a compound statement to end with a label, whereas the C
// and C++ grammars require a statement after every label; I can't
// find any place in the gcc docs that specifically addresses this
// extension; linux uses it heavily
//
// 10/17/04: It seems that gcc-3, even in C mode, rejects labels at
// the end of compound blocks.  Therefore I suspect the tolerance in
// gcc-2 was unintentional.  Oh well, Elsa allows it in all gcc modes..

nonterm(S_compound*) CompoundStatement {
  // special case for a block that ends in a label; Warning: no don't
  // do this by making a label, case and/or default form not contain
  // the statement that follows; It wouldn't work in this case:
  //   if (0) gronk: printf("hello\n");
  // The then branch would only contain the gronk label, whereas, at
  // least in gcc, it also includes the printf() call.
  -> seq:CompoundStmtHelper lesl:LabeledEmptyStatementList "}"
       { seq->stmts.append(lesl); return seq; }
}

// a sequence of labels with no statement following, not even a skip
nonterm(Statement*) LabeledEmptyStatementList {
  -> n:LabelAndColon s:LabeledEmptyStatementListOpt
       { return new S_label(loc ENDLOCARG(endloc), n, s); }
  -> "case" e:ConstantExpression ":" s:LabeledEmptyStatementListOpt
       { return new S_case(loc ENDLOCARG(endloc), e, new S_skip(loc ENDLOCARG(endloc))); }
  -> "case" e:ConstantExpression "..." e2:ConstantExpression ":" s:LabeledEmptyStatementListOpt
       { return new S_rangeCase(loc ENDLOCARG(endloc), e, e2, s); }
  -> "default" ":" s:LabeledEmptyStatementListOpt
       { return new S_default(loc ENDLOCARG(endloc), new S_skip(loc ENDLOCARG(endloc))); }
}

nonterm(Statement*) LabeledEmptyStatementListOpt {
  -> empty
       { return new S_skip(loc ENDLOCARG(endloc)); }
  -> s:LabeledEmptyStatementList
       { return s; }
}


// ----------- gcc typeof -----------
// http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Typeof.html

verbatim {
  // make a TS_typeof, and supply CV flags
  inline static TS_typeof *new_TS_typeof(SourceLocation loc, SourceLocation endloc,
                                         CVFlags cv, ASTTypeof *atype)
  {
    TS_typeof *ret = new TS_typeof(loc, endloc, atype);
    ret->cv = cv;
    return ret;
  }
}


nonterm(Declaration*) DeclSpecifier {
  // TS_typeof: triggered by TypeTypeSpecifier
  -> te:TypeofTypeSpecifier m2:UberModifierSeqOpt
       { return new Declaration(uberDeclFlags(m2),
           new_TS_typeof(loc, endloc, uberCVFlags(m2), te), NULL); }

  -> m1:UberModifierSeq te:TypeofTypeSpecifier m2:UberModifierSeqOpt
       { UberModifiers m = uberCombine(loc, m1, m2);
         return new Declaration(uberDeclFlags(m),
           new_TS_typeof(loc, endloc, uberCVFlags(m), te), NULL); }
}


nonterm(TypeSpecifier*) TypeSpecifier {
  // TS_typeof
  -> te:TypeofTypeSpecifier cv2:UberCVQualifierSeqOpt
       { return new_TS_typeof(loc, endloc, uberCVFlags(cv2), te); }

  -> cv1:UberCVQualifierSeq te:TypeofTypeSpecifier cv2:UberCVQualifierSeqOpt
       { UberModifiers cv = uberCombine(loc, cv1, cv2);
         return new_TS_typeof(loc, endloc, uberCVFlags(cv), te); }
}


// this production isolates the ambiguity to within itself, rather
// than letting it pollute upwards into TypeSpecifier
nonterm(ASTTypeof*) TypeofTypeSpecifier {
  // ambiguous:
  //   typeof(x)
  // could either be type of an expression 'x', or
  // type (of a type) called 'x'
  fun merge(L,R) { L->addAmbiguity(R); return L; }

  -> e:TypeofExpr       { return new TS_typeof_expr(e); }
  -> t:TypeofType       { return new TS_typeof_type(t); }
}


// gnu extension
nonterm(FullExpression*) TypeofExpr {
  -> "__typeof__" "(" e:Expression ")"
       { return new FullExpression(e); }
}

// gnu extension
nonterm(ASTTypeId*) TypeofType {
  -> "__typeof__" "(" t:TypeId ")"
       { return t; }
}


// ----------- gcc C++ min and max operators -----------
// http://gcc.gnu.org/onlinedocs/gcc-3.1/gcc/Min-and-Max.html
nonterm(Expression*) BinExp_mid {
  -> left:BinExp_mid "<?" right:BinExp_high
       { return new E_binary(loc ENDLOCARG(endloc), left, BIN_MINIMUM, right); }
  -> left:BinExp_mid ">?" right:BinExp_high
       { return new E_binary(loc ENDLOCARG(endloc), left, BIN_MAXIMUM, right); }
}

// it turns out gcc lets users overload them too (in/gnu/k0004.cc)
nonterm(OperatorName*) Operator {
  -> "<?"    { return new ON_operator(OP_MINIMUM); }
  -> ">?"    { return new ON_operator(OP_MAXIMUM); }
}


// ----------- gcc asm -----------
// http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Extended-Asm.html

//  nonterm(UberModifiers) VolatileOpt {
//    -> empty
//         { return UM_NONE; }
//    -> "volatile"
//         { return UM_VOLATILE; }
//  }


nonterm(StringRef) BracketedWordOpt {
  -> empty
        { return NULL; }
  -> "[" id:Identifier "]"
        { return id; }
}


nonterm(Expression*) ParenthesizedExpressionOpt {
  -> empty
        { return NULL; }
  ->  "(" e:Expression ")"
        { return e; }
}


nonterm(Constraint*) OpConstraint {
  -> name:BracketedWordOpt constr:StringLiteral e:ParenthesizedExpressionOpt
        { return new Constraint(loc, name, constr, e); }
}

nonterm(ASTList<Constraint>*) OpConstraintList {
  -> empty
        { return new ASTList<Constraint>(); }
  -> c:OpConstraint
        { return new ASTList<Constraint>(c); }
  -> list:OpConstraintList "," c:OpConstraint
        { list->append(c); return list; }
}

nonterm(Constraints*) OpConstraints {
  -> ":" o:OpConstraintList ":" i:OpConstraintList ":" c: OpConstraintList
        { return new Constraints(o, i, c); }
  -> ":" o:OpConstraintList ":" i: OpConstraintList
        { return new Constraints(o, i, NULL); }
  -> ":" o:OpConstraintList
        { return new Constraints(o, NULL, NULL); }
  -> ":" o:OpConstraintList "::" c: OpConstraintList
        { return new Constraints(o, NULL, c); }
  -> "::" i:OpConstraintList ":" c: OpConstraintList
        { return new Constraints(NULL, i, c); }
  -> "::" i:OpConstraintList 
        { return new Constraints(NULL, i, NULL); }
}

// dsw: FIX: add returning rest of semantic value
nonterm(Asm*) AsmDefinition {
  // 7/31/04: For some time we have allowed "volatile" after "asm", as
  // is documented here:
  //   http://gcc.gnu.org/onlinedocs/gcc-3.1/gcc/Extended-Asm.html
  // Recently we found some code that used "const" after "asm".  What
  // is that?  Where is it documented?

  -> "asm" q:CVQualifierSeq "(" s:StringLiteral ")" ";"
       { return new Asm(s, q); }

  // I write two rules, exposing the optionality of CVQualifierSeq at
  // this level instead of pushing it down into CVQualifierSeqOpt, to
  // avoid an S/R conflict.
  -> "asm" q:CVQualifierSeq "(" s:StringLiteral ocs:OpConstraints ")" ";"
       { return new Asm(s, q, ocs); }
  -> "asm" "(" s:StringLiteral ocs:OpConstraints ")" ";"
       { return new Asm(s, CV_NONE, ocs); }
}

// ----------- gcc asm labels -----------
// http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Asm-Labels.html
nonterm(IDeclarator*) Declarator {
  // Asm Labels after declarators; see in/gnu/asm01.c
  -> d:DirectDeclarator "asm" "(" s:StringLiteral ")"
       { return new D_asmlabel(loc, endloc, d, s); }

  // asm label + attributes ...
  -> d:DirectDeclarator "asm" "(" s:StringLiteral ")" /*DROPPED*/AttributeSpecifierList
       { return new D_asmlabel(loc, endloc, d, s); }
}

// ----------- C99 designated initializers -----------
// Designated Initializers
nonterm(Initializer*) InitializerClause {
  // obsolescent form
  // http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Designated-Inits.html
  -> d:Identifier ":" init:SimpleInitializerClause
    { return new IN_designated(loc, FakeList<Designator>::makeList(new FieldDesignator(loc, d)),
                               init); }
  // C99 official form; C99 standard section 6.7.8
  -> dl:DesignatorList "=" init:SimpleInitializerClause
    { return new IN_designated(loc, dl, init); }
  // dsw: another form I run into
  -> dl:DesignatorList init:SimpleInitializerClause
    { return new IN_designated(loc, dl, init); }
}

nonterm(FakeList<Designator>*) DesignatorList {
  -> d:Designator
    { return FakeList<Designator>::makeList(d); }
  -> d:Designator dl:DesignatorList
    { d->setNext(dl->first());
    return FakeList<Designator>::makeList(d); }
}

nonterm(Designator*) Designator {
  -> "." id:Identifier
    { return new FieldDesignator(loc, id); }
  -> "[" idx_expr:ConstantExpression "]"
    { return new SubscriptDesignator(loc, idx_expr, NULL); }
  // range designator "[ 1 ... 3 ] =".  This is a gcc-ism:
  // http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Designated-Inits.html
  -> "[" idx_expr:ConstantExpression "..." idx_expr2:ConstantExpression "]"
    { return new SubscriptDesignator(loc, idx_expr, idx_expr2); }
}


// ----------- C99 restrict keyword -----------
nonterm(enum CVFlags) CVQualifier {
  -> "restrict"              { return CV_RESTRICT; }
}

nonterm(UberModifiers) UberModifier {
  -> "restrict"              { return UM_RESTRICT; }
}

nonterm(UberModifiers) UberCVQualifier {
  -> "restrict"              { return UM_RESTRICT; }
}


// ----------- C99 qualifiers in array brackets -----------
nonterm(IDeclarator*) DirectDeclarator {
  // array with qualifier in the brackets; see the version for
  // DirectAbstractDeclarator for comments
  -> d:DirectDeclarator "[" q:CVQualifierSeq "]"
    {
      // FIX: CVQualifierSeq goes on the array
      return new D_array(loc, endloc, d, NULL /*size*/);
    }
}

nonterm(IDeclarator*) DirectAbstractDeclarator {
  // array with qualifier in the brackets
  -> d:DirectAbstractDeclaratorOpt "[" q:CVQualifierSeq "]"
    {
      // FIX: Ben says the CVQualifierSeq goes on the array itself,
      // just as if the array were a pointer and it was on the pointer
      return new D_array(loc, endloc, d, NULL /*size*/);
    }
}


// ----------- gcc2 bug: "u32 long" ----------
// gcc-2.x allows one to combine typedefs and type keywords in a
// single type specifier (e.g. in/gnu/dC0014.c); this is a bug, and is
// fixed in gcc-3.x, but the linux kernel uses it so Elsa parses it (to
// a limited degree)
nonterm(Declaration*) DeclSpecifier {
  -> n:PQTypeName BuggyGccTypeModifier/*ignored*/ m2:UberModifierSeqOpt
     {
       diagnose3(LO.allowModifiersWithTypedefNames, loc,
                 diag::err_typedef_and_type, diag::note_gcc2_bug_allows);
       return new Declaration(uberDeclFlags(m2),
         new_TS_name(loc, endloc, uberCVFlags(m2), n, false /*typename*/), NULL);
     }

  -> m1:UberModifierSeq n:PQTypeName BuggyGccTypeModifier/*ignored*/ m2:UberModifierSeqOpt
     {
       diagnose3(LO.allowModifiersWithTypedefNames, loc,
                 diag::err_typedef_and_type, diag::note_gcc2_bug_allows);
       UberModifiers m = uberCombine(loc, m1, m2);
       return new Declaration(uberDeclFlags(m),
         new_TS_name(loc, endloc, uberCVFlags(m), n, false /*typename*/), NULL);
     }
}

// these are the only ones that could be meaningfully combined with
// an existing typedef, I think
nonterm BuggyGccTypeModifier {
  -> "long";
  -> "short";
  -> "signed";
  -> "unsigned";

  // make it a sequence...
  -> "long"       BuggyGccTypeModifier;
  -> "short"      BuggyGccTypeModifier;
  -> "signed"     BuggyGccTypeModifier;
  -> "unsigned"   BuggyGccTypeModifier;
}


// ------------ gcc computed goto ----------
// http://gcc.gnu.org/onlinedocs/gcc-3.1/gcc/Labels-as-Values.html
nonterm(Expression*) UnaryExpression {
  -> "&&" n:Identifier
       { return new E_addrOfLabel(loc ENDLOCARG(endloc), n); }
}

nonterm(Statement*) Statement {
  -> "goto" "*" e:Expression ";"
       { return new S_computedGoto(loc ENDLOCARG(endloc), e); }
}


// ----------- gcc/C99 complex/imaginary ----------
// http://gcc.gnu.org/onlinedocs/gcc-3.1/gcc/Complex.html
// C99 6.2.5p11, 6.7.2, Annex G
nonterm(UberModifiers) UberTypeKeyword {
  -> "_Bool"         { return UM_BOOL; }
  -> "_Complex"      { return UM_COMPLEX; }
  -> "_Imaginary"    { return UM_IMAGINARY; }
}

// The gcc manual says the syntax is "__real__" Expression, but I'll
// take a conservative approach for now and only allow primary
// expressions, thus avoiding the need to specify precedence of these
// keywords.
//
// I've chosen to create E_fieldAcc AST nodes because they are similar,
// in that these are component accesses.
nonterm(Expression*) PrimaryExpression {
  -> "__real__" e:PrimaryExpression
     { return new E_fieldAcc(loc, endloc, e, new PQ_name(loc, endloc, str("__real__"))); }
  -> "__imag__" e:PrimaryExpression
     { return new E_fieldAcc(loc, endloc, e, new PQ_name(loc, endloc, str("__imag__"))); }
}


// ----------- gcc __attribute__ -----------
// This nonterminal gives me a good place to solve the ambiguity
// between associating the attrs with the label and associating
// them with the next declaration.
nonterm(StringRef) LabelAndColon {
  -> n:Identifier ":" /*DROPPED*/AttributeSpecifierList     precedence(TOK_PREFER_REDUCE)
       { return n; }
}

/* tglek: Commenting this out so I can attach attributes to classes below
// attributes between classkeys and their names
nonterm(enum TypeIntr) ClassKey {
  // *not* AttributeSpecifierList; this context is naturally repeating
  -> k:ClassKey / *DROPPED* /AttributeSpecifier       { return k; }
}
*/

nonterm(TypeSpecifier*) ElaboratedTypeSpecifier {
  -> k:ClassKey /*DROPPED*/AttributeSpecifier n:PQTypeName    { return new TS_elaborated(loc, endloc, k, n); }
}

nonterm(TS_classSpec*) ClassSpecifier {
  -> k:ClassKey as:AttributeSpecifierList n:ClassHeadNameOpt b:BaseClauseOpt "{" memb:MemberDeclarationSeqOpt "}"
    { 
      popClassName();
      TS_classSpec *ts = new TS_classSpec(loc, endloc, k, n, b, memb);
      ts->alist = as;
      return ts;
    }
}

// attributes after "enum"
nonterm(TypeSpecifier*) ElaboratedTypeSpecifier {
  -> "enum" /*DROPPED*/AttributeSpecifierList n:PQTypeName
       { return new TS_elaborated(loc, endloc, TI_ENUM, n); }
}

nonterm(TS_enumSpec*) EnumSpecifier {
  -> "enum" /*DROPPED*/AttributeSpecifierList "{" list:EnumeratorListOpt "}"
       { return new TS_enumSpec(loc, endloc, NULL /*name*/, list); }

  // Adding this adds one S/R conflict... it was 3 until I changed
  // Identifier to PQTypeName.  I think cc.gr should similarly use
  // PQName instead of Identifier, and catch qualifiers in tcheck...
  -> "enum" /*DROPPED*/AttributeSpecifierList n:PQTypeName "{" list:EnumeratorListOpt "}"
       { return new TS_enumSpec(loc, endloc, n->getName(), list); }
}


// As can be seen in the note at the end of this file, allowing
// attributes in these two nonterminals is responsible for the
// majority of the tolerance for them.  However, as UberModifiers are
// an 'enum', this is also why retaining attributes in the AST is a
// bit challenging: right here, there is nothing of substance to
// attach them to!
//
// To fix this, one would probably have to find all occurrences of
// UberModifier and UberCVQualifier, and add an alternative that goes
// "... attr(one!) attrs-or-others-seq-opt ...", like below where I
// use CVQualAttrSeqOpt.
//
// If all you care about is retaining one specific attribute that has
// no arguments, you could get by with a new UberModifier flag and
// associated DeclFlag.
nonterm(UberModifiers) UberModifier {
  -> AttributeSpecifier      { return UM_NONE; }
}

nonterm(UberModifiers) UberCVQualifier {
  -> AttributeSpecifier      { return UM_NONE; }
}


// attribute after the "," in a sequence of declarators
nonterm(FakeList<Declarator>*) InitDeclaratorList {
  -> d:InitDeclarator "," /*DROPPED*/AttributeSpecifierList list:InitDeclaratorList
       { d->setNext(list->first());
         return FakeList<Declarator>::makeList(d); }
}


// cv-qualifiers mixed with __attribute__ arbitrarily
nonterm(enum CVFlags) CVQualAttrSeqOpt {
  -> empty                             { return CV_NONE; }
  -> s:CVQualAttrSeq                   { return s; }
}

nonterm(enum CVFlags) CVQualAttrSeq {
  -> q:CVQualAttr                      { return q; }
  -> q:CVQualAttr s:CVQualAttrSeq      { return q | s; }
}

nonterm(enum CVFlags) CVQualAttr {
  -> q:CVQualifier                     { return q; }
  -> AttributeSpecifier                { return CV_NONE; }
}


nonterm(IDeclarator*) Declarator {
  // "*", then some cv, then *one* __attribute__, which causes the
  // parser to commit to this production, then cv+attr seq
  -> "*" cv:CVQualifierSeqOpt /*DROPPED*/AttributeSpecifier cv2:CVQualAttrSeqOpt d:Declarator
       { return new D_pointer(loc, endloc, cv | cv2, d); }

  // perhaps attributes should be allowed after "&" and "C::*"?

  // this is slightly more tolerant than gcc is, since it allows
  // attributes just inside the ")" of a D_grouping, whereas gcc
  // doesn't
  -> d:DirectDeclarator attr:AttributeSpecifierList
       { return new D_attribute(loc, d, attr); }
}


nonterm(IDeclarator*) DirectDeclarator {
  -> "(" attr:AttributeSpecifierList d:Declarator ")"
       { return new D_attribute(loc, d, attr); }
}


nonterm(IDeclarator*) AbstractDeclarator {
  -> "*" cv:CVQualifierSeqOpt attrspec:AttributeSpecifier cv2:CVQualAttrSeqOpt d:AbstractDeclaratorOpt
       { return new D_pointer(loc, endloc, cv | cv2, d); }

  -> d:DirectAbstractDeclarator attr:AttributeSpecifierList
       { return new D_attribute(loc, d, attr); }
}

nonterm(IDeclarator*) DirectAbstractDeclarator {
  -> "(" /*DROPPED*/AttributeSpecifierList d:AbstractDeclarator ")"
       { return new D_grouping(loc, endloc, d); }
}

// dsw: attributes after bitfields; from the kernel:
// UCHAR8 SampleResolution:2 __attribute__ ((packed));
//
// sm: the reason this wasn't handled by my catch-all Declarator
// case above is that the bitfield syntax doesn't explicitly refer
// to the Declarator nonterminal
nonterm(Declarator*) MemberDeclarator {
  -> n:IdentifierOpt ":" e:ConstantExpression /*DROPPED*/AttributeSpecifierList    // bitfield
       // this body is an exact copy of the cc.gr one without attributes
       { return new Declarator(new D_bitfield(loc, endloc, n? new PQ_name(loc, endloc, n) : NULL, e),
                               NULL /*init*/); }
}

// dsw: from Taras Glek, tglek at mozilla dot com
nonterm(DeclFlags) CDtorModifier {
 -> /*DROPPED*/AttributeSpecifier      { return DF_NONE; }
}

// 2007-09-15: This is in the gcc-4.2.1 headers.
nonterm(TF_namespaceDefn*) NamespaceDefinition {
  -> "namespace" n:IdentifierOpt /*DROPPED*/AttributeSpecifierList "{" unit:TranslationUnit "}"
       {
         TF_namespaceDefn *ret = new TF_namespaceDefn(loc, n, NULL /*forms*/);
         ret->forms.concat(unit->topForms);     // steal list contents
         delete unit;
         return ret;
       }
}


// -- attributes themselves --
// http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Attribute-Syntax.html

// "A word (which may be an identifier such as unused, or a reserved
// word such as const)."
nonterm(StringRef) AttributeWord {
  // non-keyword name
  -> n:TOK_NAME         { return n; }

  // keywords
  -> "asm"              { return str("asm"); }
  -> "auto"             { return str("auto"); }
  -> "break"            { return str("break"); }
  -> "bool"             { return str("bool"); }
  -> "case"             { return str("case"); }
  -> "catch"            { return str("catch"); }
  -> "char"             { return str("char"); }
  -> "class"            { return str("class"); }
  -> "const"            { return str("const"); }
  -> "const_cast"       { return str("const_cast"); }
  -> "continue"         { return str("continue"); }
  -> "default"          { return str("default"); }
  -> "delete"           { return str("delete"); }
  -> "do"               { return str("do"); }
  -> "double"           { return str("double"); }
  -> "dynamic_cast"     { return str("dynamic_cast"); }
  -> "else"             { return str("else"); }
  -> "enum"             { return str("enum"); }
  -> "explicit"         { return str("explicit"); }
  -> "export"           { return str("export"); }
  -> "extern"           { return str("extern"); }
  -> "false"            { return str("false"); }
  -> "float"            { return str("float"); }
  -> "for"              { return str("for"); }
  -> "friend"           { return str("friend"); }
  -> "goto"             { return str("goto"); }
  -> "if"               { return str("if"); }
  -> "inline"           { return str("inline"); }
  -> "int"              { return str("int"); }
  -> "long"             { return str("long"); }
  -> "mutable"          { return str("mutable"); }
  -> "namespace"        { return str("namespace"); }
  -> "new"              { return str("new"); }
  -> "operator"         { return str("operator"); }
  -> "private"          { return str("private"); }
  -> "protected"        { return str("protected"); }
  -> "public"           { return str("public"); }
  -> "register"         { return str("register"); }
  -> "reinterpret_cast" { return str("reinterpret_cast"); }
  -> "return"           { return str("return"); }
  -> "short"            { return str("short"); }
  -> "signed"           { return str("signed"); }
  -> "sizeof"           { return str("sizeof"); }
  -> "static"           { return str("static"); }
  -> "static_cast"      { return str("static_cast"); }
  -> "struct"           { return str("struct"); }
  -> "switch"           { return str("switch"); }
  -> "template"         { return str("template"); }
  -> "this"             { return str("this"); }
  -> "throw"            { return str("throw"); }
  -> "true"             { return str("true"); }
  -> "try"              { return str("try"); }
  -> "typedef"          { return str("typedef"); }
  -> "typeid"           { return str("typeid"); }
  -> "typename"         { return str("typename"); }
  -> "union"            { return str("union"); }
  -> "unsigned"         { return str("unsigned"); }
  -> "using"            { return str("using"); }
  -> "virtual"          { return str("virtual"); }
  -> "void"             { return str("void"); }
  -> "volatile"         { return str("volatile"); }
  -> "wchar_t"          { return str("wchar_t"); }
  -> "while"            { return str("while"); }

  // don't know if I need to allow these; gcc 2.95.3 doesn't like them
  //  // GNU extensions
  //  TOK___ATTRIBUTE__,       "__attribute__",             :    n
  //  TOK___LABEL__,           "__label__",                 :    n
  //  TOK___TYPEOF__,          "__typeof__",                :    n
}

nonterm(FakeList<ArgExpression>*) CommaSepExpressionListOpt {
  -> empty                 { return FakeList<ArgExpression>::emptyList(); }
  -> el:ExpressionList     { return el; }
}

nonterm(FakeList<ArgExpression>*) AttributeParameters {
//    -> id:Identifier "," exprs:CommaSepExpressionListOpt ;
  // NOTE: the below includes the above, except that the first
  // expression, if an identifier, should not be typechecked as an
  // E_variable, since it need not match a declared name; first it
  // should be checked against known attribute parameters (maybe?).
  -> exprs:CommaSepExpressionListOpt    { return exprs; }
}

nonterm(Attribute*) Attribute {
  -> empty
     { return new AT_empty(loc); }

  -> w:AttributeWord
     { return new AT_word(loc, w); }

  -> w:AttributeWord "(" ap:AttributeParameters ")"
     { return new AT_func(loc, w, ap); }
}

nonterm(AttributeSpecifier*) AttributeList {
  -> at:Attribute
     { return new AttributeSpecifier(at, NULL /*next*/); }

  -> at:Attribute "," ap:AttributeList
     { return new AttributeSpecifier(at, ap); }
}

nonterm(AttributeSpecifier*) AttributeSpecifier {
  -> "__attribute__" "(" "(" ap:AttributeList ")" ")"
     { return ap; }
}

nonterm(AttributeSpecifierList*) AttributeSpecifierList {
  -> as:AttributeSpecifier
     { return new AttributeSpecifierList(as, NULL /*next*/); }

  -> as:AttributeSpecifier asl:AttributeSpecifierList
     { return new AttributeSpecifierList(as, asl); }
}

// quarl 2006-06-14
//    'using namespace N __attribute__(__strong__)'
//    see in/gnu/k0009.cc or
//    /usr/include/c++/3.4/i486-linux-gnu/bits/c++config.h

nonterm(NamespaceDecl*) NamespaceDecl {
  -> "using" "namespace" n:IdExpression AttributeSpecifierList ";"
       { xunimp(stringc << loc << " using namespace __attribute__"
                " (a86c8a1e-2cd7-41bd-8a23-f9049358c166)");
         return new ND_usingDir(n); }
}


/*
  2005-08-13: I have now added retention of attributes in some
  places.  All places where it is still *not* retained are now
  marked with "DROPPED".  My plan is to incrementally retain
  more of the attributes as the need arises.

  Implementation of __attribute__ (sm, 8/21/04).

  NOTE: The current implementation drops all __attribute__s on the
  floor after parsing them!  That is not ideal.  However, as
  attributes can go in places that don't have ready access to (say) a
  Type or a Declarator to attach them to, retaining them in the AST
  isn't a trivial change.

  The spec at
  http://gcc.gnu.org/onlinedocs/gcc-3.1/gcc/Attribute-Syntax.html does
  a reasonably good job of documenting where __attribute__ can go and
  what it means.  There are a number of things unclear about that
  description, so I explored a bit with gcc-2 and gcc-2.
  in/gnu/attr02.c contains a variety of syntax that gcc-3 accepts;
  gcc-2 accepts most of it.

  Based on this exploration, I decided to put attributes in a number
  of places in cc.gr (via this gnu.gr extension grammar), listed
  below.  In some cases I also determined (manually) the set of
  contexts in which the modified construct would appear, so I could
  better predict the effect of the modifications.

    * right after ":" in labeled statement (did this with LabelAndColon)

    * after ClassKey and "enum" where they occur

    * UberModifer
        - in DeclSpecifier
          - in SimpleDeclaration
            - in ForInitStatement
            - in BlockDeclaration
              - as a Statement
              - as a TopForm
              - in an ExplicitInstantiation
          - in FunctionDefinition
          - in MemberDeclaration
          - in TemplateDeclaration, after the "template <...>"

    * UberCVQualifier
        - in TypeSpecifier
          - in ParameterDeclaration
          - in Condition
          - in NewTypeId      ------------+   below here are places attr would
            - in E_new                    |   be allowed, even though I don't
          - in TypeId                     V   really want it to ...
            - in E_keywordCast
            - in E_typeidType
            - in E_sizeofType
            - in E_new
            - in E_cast
            - in TemplateTypeParameter default type
            - in TemplateArgument (TA_type)
            - in throw() cause
          - in ConversionTypeId
          - in HandlerParameter

    * after "," in InitDeclaratorList's 2nd clause
        - gets attr at outermost declarator level for 2nd or later declarator

    * after "*" in (Abstract)Declarator
    * after "(" in Direct(Abstract)Declarator D_grouping
    / after "C::*" in (Abstract)Declarator
    / after "&" in (Abstract)Declarator

    * likewise for AbstractDeclarator

      every place that (Abstract)Declarator occurs, other than in its recursive
      structure, add an alternative with attrs after the Declarator
    ~   - in fact, generalize that to let the "Asm Labels" go there too
    *   - better: in Declarator after the Direct(Abstract)Declarator

  The two "/" above means I didn't end up putting them after the C++
  type constructors, since I doubt I'll need them there.

  I found it useful to keep track, while I was modifying the grammar, of
  the conflict totals.  This table shows the effect on conflicts of my
  changes:

    conflicts at various stages                               S/R   R/R
    -------------------------------------------------------   ---------
    starting                                                  142   104

    removed attrs after ClassSpecifier in ElaboratedOrSpec    140   104

    removed attrs between "*" and cv in Declarator            139   104
    added attrs after cv in Declarator                        140   104
    added cvattrseqopt after attr (one!) in Declarator        140   104

    removed attrs between "*" and cv in AbstractDeclarator    138   104
    removed attrs after DAD in AbstractDeclarator             138   104
    added attrs after cv in AbstractDeclarator                140   111
    added cvattrseqopt after attr (one!) in ADeclarator       140   104
    added attrs after DAD in AbstractDeclarator               140   104

    added attrs after class/enum in ElaboratedTypeSpecifier   140   104
    for class, added to ClassKey instead                      140   104

    added attrs after "enum" in EnumSpecifier                 141   104

    removed attrspec from SimpleDeclaration (printk thing)     75   104

    added attr to UberModifier                                 75   176

    removed attr after labeled statements                      75   110

    added attr to UberCVQualifier                              84   114

    added attr after "," in InitDeclarator                     84   114

    added attr after ":" in LabeledEmptyStatementList          84   116

    removed attr after ":" in LabeledEmptyStatementList        84   114

    created LabelAndColon in cc.gr                             81   108
    added attrs after LabelAndColon                            83   108
    added attrs after LabelAndColon with high precedence       82   108
    added LabelAndColon to the LabeledEmptyStatementList       82   108

*/


// EOF