gcc2.9.txt

编译原理中的First集与 Follow集生成程序

	;

identifier_defn:
	  IDENTIFIER_DEFN
	| TYPENAME_DEFN
	| PTYPENAME_DEFN
	;

explicit_instantiation:
	  TEMPLATE begin_explicit_instantiation typespec ';'
		{ do_type_instantiation ($3.t, NULL_TREE);
		  yyungetc (';', 1); }
          end_explicit_instantiation
	| TEMPLATE begin_explicit_instantiation typed_declspecs declarator
		{ tree specs = strip_attrs ($3.t);
		  do_decl_instantiation (specs, $4, NULL_TREE); }
          end_explicit_instantiation
	| TEMPLATE begin_explicit_instantiation notype_declarator
		{ do_decl_instantiation (NULL_TREE, $3, NULL_TREE); }
          end_explicit_instantiation
	| TEMPLATE begin_explicit_instantiation constructor_declarator
		{ do_decl_instantiation (NULL_TREE, $3, NULL_TREE); }
          end_explicit_instantiation
	| SCSPEC TEMPLATE begin_explicit_instantiation typespec ';'
		{ do_type_instantiation ($4.t, $1);
		  yyungetc (';', 1); }
          end_explicit_instantiation
	| SCSPEC TEMPLATE begin_explicit_instantiation typed_declspecs 
          declarator
		{ tree specs = strip_attrs ($4.t);
		  do_decl_instantiation (specs, $5, $1); }
          end_explicit_instantiation
	| SCSPEC TEMPLATE begin_explicit_instantiation notype_declarator
		{ do_decl_instantiation (NULL_TREE, $4, $1); }
          end_explicit_instantiation
	| SCSPEC TEMPLATE begin_explicit_instantiation constructor_declarator
		{ do_decl_instantiation (NULL_TREE, $4, $1); }
          end_explicit_instantiation
	;

begin_explicit_instantiation: 
      { begin_explicit_instantiation(); }
    ;
    
end_explicit_instantiation: 
      { end_explicit_instantiation(); }
    ;

/* The TYPENAME expansions are to deal with use of a template class name as
  a template within the class itself, where the template decl is hidden by
  a type decl.  Got all that?  */

template_type:
	  PTYPENAME '<' template_arg_list_opt template_close_bracket
	    .finish_template_type
                { $$ = $5; }
	| TYPENAME  '<' template_arg_list_opt template_close_bracket
	    .finish_template_type
                { $$ = $5; }
	| self_template_type
	;

apparent_template_type:
	  template_type
	| identifier '<' template_arg_list_opt '>'
	    .finish_template_type
		{ $$ = $5; }
    ;
    
self_template_type:
	  SELFNAME  '<' template_arg_list_opt template_close_bracket
	    .finish_template_type
                { $$ = $5; }
	;

.finish_template_type:
                { 
		  if (yychar == YYEMPTY)
		    yychar = YYLEX;

		  $$ = finish_template_type ($<ttype>-3, $<ttype>-1, 
					     yychar == SCOPE);
		}
	;

template_close_bracket:
	  '>'
	| RSHIFT 
		{
		  /* Handle `Class<Class<Type>>' without space in the `>>' */
		  pedwarn ("`>>' should be `> >' in template class name");
		  yyungetc ('>', 1);
		}
	;

template_arg_list_opt:
         /* empty */
                 { $$ = NULL_TREE; }
       | template_arg_list
       ;

template_arg_list:
        template_arg
		{ $$ = build_tree_list (NULL_TREE, $$); }
	| template_arg_list ',' template_arg
		{ $$ = chainon ($$, build_tree_list (NULL_TREE, $3)); }
	;

template_arg:
	  type_id
		{ $$ = groktypename ($1.t); }
	| PTYPENAME
		{ $$ = lastiddecl; }
	| expr_no_commas  %prec ARITHCOMPARE
	;

unop:
	  '-'
		{ $$ = NEGATE_EXPR; }
	| '+'
		{ $$ = CONVERT_EXPR; }
	| PLUSPLUS
		{ $$ = PREINCREMENT_EXPR; }
	| MINUSMINUS
		{ $$ = PREDECREMENT_EXPR; }
	| '!'
		{ $$ = TRUTH_NOT_EXPR; }
	;

expr:
	  nontrivial_exprlist
		{ $$ = build_x_compound_expr ($$); }
	| expr_no_commas
	;

paren_expr_or_null:
	LEFT_RIGHT
		{ error ("ANSI C++ forbids an empty condition for `%s'",
			 cond_stmt_keyword);
		  $$ = integer_zero_node; }
	| '(' expr ')'
                { $$ = $2; }
	;

paren_cond_or_null:
	LEFT_RIGHT
		{ error ("ANSI C++ forbids an empty condition for `%s'",
			 cond_stmt_keyword);
		  $$ = integer_zero_node; }
	| '(' condition ')'
                { $$ = $2; }
	;

xcond:
	  /* empty */
		{ $$ = NULL_TREE; }
	| condition
	| error
		{ $$ = NULL_TREE; }
	;

condition:
	  type_specifier_seq declarator maybeasm maybe_attribute '='
		{ {
		  tree d;
		  for (d = getdecls (); d; d = TREE_CHAIN (d))
		    if (TREE_CODE (d) == TYPE_DECL) {
		      tree s = TREE_TYPE (d);
		      if (TREE_CODE (s) == RECORD_TYPE)
			cp_error ("definition of class `%T' in condition", s);
		      else if (TREE_CODE (s) == ENUMERAL_TYPE)
			cp_error ("definition of enum `%T' in condition", s);
		    }
		  }
		  current_declspecs = $1.t;
		  $<itype>5 = suspend_momentary ();
		  $<ttype>$ = start_decl ($<ttype>2, current_declspecs, 1,
					  $4, /*prefix_attributes*/ NULL_TREE);
		}
	  init
		{ 
		  cp_finish_decl ($<ttype>6, $7, $4, 1, LOOKUP_ONLYCONVERTING);
		  resume_momentary ($<itype>5);
		  $$ = convert_from_reference ($<ttype>6); 
		  if (TREE_CODE (TREE_TYPE ($$)) == ARRAY_TYPE)
		    cp_error ("definition of array `%#D' in condition", $$); 
		}
	| expr
	;

compstmtend:
	  '}'
	| maybe_label_decls stmts '}'
	| maybe_label_decls stmts error '}'
	| maybe_label_decls error '}'
	;

already_scoped_stmt:
	  '{'
                { $<ttype>$ = begin_compound_stmt (1); }
	  compstmtend
                { finish_compound_stmt (1, $<ttype>2); }
	| simple_stmt
	;


nontrivial_exprlist:
	  expr_no_commas ',' expr_no_commas
		{ $$ = expr_tree_cons (NULL_TREE, $$, 
		                  build_expr_list (NULL_TREE, $3)); }
	| expr_no_commas ',' error
		{ $$ = expr_tree_cons (NULL_TREE, $$, 
		                  build_expr_list (NULL_TREE, error_mark_node)); }
	| nontrivial_exprlist ',' expr_no_commas
		{ chainon ($$, build_expr_list (NULL_TREE, $3)); }
	| nontrivial_exprlist ',' error
		{ chainon ($$, build_expr_list (NULL_TREE, error_mark_node)); }
	;

nonnull_exprlist:
	  expr_no_commas
		{ $$ = build_expr_list (NULL_TREE, $$); }
	| nontrivial_exprlist
	;

unary_expr:
	  primary  %prec UNARY
		{ $$ = $1; }
	/* __extension__ turns off -pedantic for following primary.  */
	| extension cast_expr  	  %prec UNARY
		{ $$ = $2;
		  pedantic = $<itype>1; }
	| '*' cast_expr   %prec UNARY
		{ $$ = build_x_indirect_ref ($2, "unary *"); }
	| '&' cast_expr   %prec UNARY
		{ $$ = build_x_unary_op (ADDR_EXPR, $2); }
	| '~' cast_expr
		{ $$ = build_x_unary_op (BIT_NOT_EXPR, $2); }
	| unop cast_expr  %prec UNARY
                { $$ = finish_unary_op_expr ($1, $2); }
	/* Refer to the address of a label as a pointer.  */
	| ANDAND identifier
		{ if (pedantic)
		    pedwarn ("ANSI C++ forbids `&&'");
  		  $$ = finish_label_address_expr ($2); }
	| SIZEOF unary_expr  %prec UNARY
		{ $$ = expr_sizeof ($2); }
	| SIZEOF '(' type_id ')'  %prec HYPERUNARY
		{ $$ = c_sizeof (groktypename ($3.t));
		  check_for_new_type ("sizeof", $3); }
	| ALIGNOF unary_expr  %prec UNARY
		{ $$ = grok_alignof ($2); }
	| ALIGNOF '(' type_id ')'  %prec HYPERUNARY
		{ $$ = c_alignof (groktypename ($3.t)); 
		  check_for_new_type ("alignof", $3); }

	/* The %prec EMPTY's here are required by the = init initializer
	   syntax extension; see below.  */
	| new new_type_id  %prec EMPTY
		{ $$ = build_new (NULL_TREE, $2.t, NULL_TREE, $1); 
		  check_for_new_type ("new", $2); }
	| new new_type_id new_initializer
		{ $$ = build_new (NULL_TREE, $2.t, $3, $1); 
		  check_for_new_type ("new", $2); }
	| new new_placement new_type_id  %prec EMPTY
		{ $$ = build_new ($2, $3.t, NULL_TREE, $1); 
		  check_for_new_type ("new", $3); }
	| new new_placement new_type_id new_initializer
		{ $$ = build_new ($2, $3.t, $4, $1); 
		  check_for_new_type ("new", $3); }
        /* The .begin_new_placement in the following rules is
	   necessary to avoid shift/reduce conflicts that lead to
	   mis-parsing some expressions.  Of course, these constructs
	   are not really new-placement and it is bogus to call
	   begin_new_placement.  But, the parser cannot always tell at this
	   point whether the next thing is an expression or a type-id,
	   so there is nothing we can do.  Fortunately,
	   begin_new_placement does nothing harmful.  When we rewrite
	   the parser, this lossage should be removed, of course.  */
	| new '(' .begin_new_placement type_id .finish_new_placement
            %prec EMPTY
		{ $$ = build_new (NULL_TREE, groktypename($4.t),
				  NULL_TREE, $1); 
		  check_for_new_type ("new", $4); }
	| new '(' .begin_new_placement type_id .finish_new_placement
            new_initializer
		{ $$ = build_new (NULL_TREE, groktypename($4.t), $6, $1); 
		  check_for_new_type ("new", $4); }
	| new new_placement '(' .begin_new_placement type_id
	    .finish_new_placement   %prec EMPTY
		{ $$ = build_new ($2, groktypename($5.t), NULL_TREE, $1); 
		  check_for_new_type ("new", $5); }
	| new new_placement '(' .begin_new_placement type_id
	    .finish_new_placement  new_initializer
		{ $$ = build_new ($2, groktypename($5.t), $7, $1); 
		  check_for_new_type ("new", $5); }

	| delete cast_expr  %prec UNARY
		{ $$ = delete_sanity ($2, NULL_TREE, 0, $1); }
	| delete '[' ']' cast_expr  %prec UNARY
		{ $$ = delete_sanity ($4, NULL_TREE, 1, $1);
		  if (yychar == YYEMPTY)
		    yychar = YYLEX; }
	| delete '[' expr ']' cast_expr  %prec UNARY
		{ $$ = delete_sanity ($5, $3, 2, $1);
		  if (yychar == YYEMPTY)
		    yychar = YYLEX; }
	| REALPART cast_expr %prec UNARY
		{ $$ = build_x_unary_op (REALPART_EXPR, $2); }
	| IMAGPART cast_expr %prec UNARY
		{ $$ = build_x_unary_op (IMAGPART_EXPR, $2); }
	;

        /* Note this rule is not suitable for use in new_placement
	   since it uses NULL_TREE as the argument to
	   finish_new_placement.  This rule serves only to avoid
	   reduce/reduce conflicts in unary_expr.  See the comments
	   there on the use of begin/finish_new_placement.  */
.finish_new_placement:
	  ')'
                { finish_new_placement (NULL_TREE, $<itype>-1); }
    ;
    
.begin_new_placement:
                { $$ = begin_new_placement (); }
    ;
    
new_placement:
	  '(' .begin_new_placement nonnull_exprlist ')'
                { $$ = finish_new_placement ($3, $2); }
	| '{' .begin_new_placement nonnull_exprlist '}'
                { cp_pedwarn ("old style placement syntax, use () instead");
		  $$ = finish_new_placement ($3, $2); }
	;

new_initializer:
	  '(' nonnull_exprlist ')'
		{ $$ = $2; }
	| LEFT_RIGHT
		{ $$ = NULL_TREE; }
	| '(' typespec ')'
		{
		  cp_error ("`%T' is not a valid expression", $2.t);
		  $$ = error_mark_node;
		}
	/* GNU extension so people can use initializer lists.  Note that
	   this alters the meaning of `new int = 1', which was previously
	   syntactically valid but semantically invalid.  */
	| '=' init
		{
		  if (pedantic)
		    pedwarn ("ANSI C++ forbids initialization of new expression with `='");
		  if (TREE_CODE ($2) != TREE_LIST
		      && TREE_CODE ($2) != CONSTRUCTOR)
		    $$ = build_expr_list (NULL_TREE, $2);
		  else
		    $$ = $2;
		}
	;

/* This is necessary to postpone reduction of `int ((int)(int)(int))'.  */
regcast_or_absdcl:
	  '(' type_id ')'  %prec EMPTY
		{ $2.t = finish_parmlist (build_tree_list (NULL_TREE, $2.t), 0);
		  $$ = make_call_declarator (NULL_TREE, $2.t, NULL_TREE, NULL_TREE);
		  check_for_new_type ("cast", $2); }
	| regcast_or_absdcl '(' type_id ')'  %prec EMPTY
		{ $3.t = finish_parmlist (build_tree_list (NULL_TREE, $3.t), 0); 
		  $$ = make_call_declarator ($$, $3.t, NULL_TREE, NULL_TREE);
		  check_for_new_type ("cast", $3); }
	;

cast_expr:
	  unary_expr
	| regcast_or_absdcl unary_expr  %prec UNARY
		{ $$ = reparse_absdcl_as_casts ($$, $2); }
	| regcast_or_absdcl '{' initlist maybecomma '}'  %prec UNARY
		{ 
		  tree init = build_nt (CONSTRUCTOR, NULL_TREE,
					nreverse ($3)); 
		  if (pedantic)
		    pedwarn ("ANSI C++ forbids constructor-expressions");
		  /* Indicate that this was a GNU C constructor expression.  */
		  TREE_HAS_CONSTRUCTOR (init) = 1;

		  $$ = reparse_absdcl_as_casts ($$, init);
		}
	;

expr_no_commas:
	  cast_expr
	/* Handle general members.  */
	| expr_no_commas POINTSAT_STAR expr_no_commas
		{ $$ = build_x_binary_op (MEMBER_REF, $$, $3); }
	| expr_no_commas DOT_STAR expr_no_commas
		{ $$ = build_m_component_ref ($$, $3); }
	| expr_no_commas '+' expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas '-' expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas '*' expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas '/' expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas '%' expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas LSHIFT expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas RSHIFT expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas ARITHCOMPARE expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas '<' expr_no_commas
		{ $$ = build_x_binary_op (LT_EXPR, $$, $3); }
	| expr_no_commas '>' expr_no_commas
		{ $$ = build_x_binary_op (GT_EXPR, $$, $3); }
	| expr_no_commas EQCOMPARE expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas MIN_MAX expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas '&' expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas '|' expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas '^' expr_no_commas
		{ $$ = build_x_binary_op ($2, $$, $3); }
	| expr_no_commas ANDAND expr_no_commas
		{ $$ = build_x_binary_op (TRUTH_ANDIF_EXPR, $$, $3); }
	| expr_no_commas OROR expr_no_commas
		{ $$ = build_x_binary_op (TRUTH_ORIF_EXPR, $$, $3); }
	| expr_no_commas '?' xexpr ':' expr_no_commas
		{ $$ = build_x_conditional_expr ($$, $3, $5); }
	| expr_no_commas '=' expr_no_commas
		{ $$ = build_x_modify_expr ($$, NOP_EXPR, $3);