gcc/ada/nlists.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                               N L I S T S                                --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2005, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package provides facilities for manipulating lists of nodes (see
  35 --  package Atree for format and implementation of tree nodes). The Link field
  36 --  of the nodes is used as the forward pointer for these lists. See also
  37 --  package Elists which provides another form of lists that are not threaded
  38 --  through the nodes (and therefore allow nodes to be on multiple lists).
  39
  40 with System;
  41 with Types; use Types;
  42
  43 package Nlists is
  44
  45    --  A node list is a list of nodes in a special format that means that
  46    --  nodes can be on at most one such list. For each node list, a list
  47    --  header is allocated in the lists table, and a List_Id value references
  48    --  this header, which may be used to access the nodes in the list using
  49    --  the set of routines that define this interface.
  50
  51    --  Note: node lists can contain either nodes or entities (extended nodes)
  52    --  or a mixture of nodes and extended nodes.
  53
  54    function Last_List_Id return List_Id;
  55    pragma Inline (Last_List_Id);
  56    --  Returns Id of last allocated list header
  57
  58    function Lists_Address return System.Address;
  59    pragma Inline (Lists_Address);
  60    --  Return address of Lists table (used in Back_End for Gigi call)
  61
  62    function Num_Lists return Nat;
  63    pragma Inline (Num_Lists);
  64    --  Number of currently allocated lists
  65
  66    function New_List return List_Id;
  67    --  Creates a new empty node list. Typically this is used to initialize
  68    --  a field in some other node which points to a node list where the list
  69    --  is then subsequently filled in using Append calls.
  70
  71    function Empty_List return List_Id renames New_List;
  72    --  Used in contexts where an empty list (as opposed to an initially empty
  73    --  list to be filled in) is required.
  74
  75    function New_List (Node : Node_Id) return List_Id;
  76    --  Build a new list initially containing the given node
  77
  78    function New_List (Node1, Node2 : Node_Id) return List_Id;
  79    --  Build a new list initially containing the two given nodes
  80
  81    function New_List (Node1, Node2, Node3 : Node_Id) return List_Id;
  82    --  Build a new list initially containing the three given nodes
  83
  84    function New_List (Node1, Node2, Node3, Node4 : Node_Id) return List_Id;
  85    --  Build a new list initially containing the four given nodes
  86
  87    function New_List
  88      (Node1 : Node_Id;
  89       Node2 : Node_Id;
  90       Node3 : Node_Id;
  91       Node4 : Node_Id;
  92       Node5 : Node_Id) return List_Id;
  93    --  Build a new list initially containing the five given nodes
  94
  95    function New_List
  96      (Node1 : Node_Id;
  97       Node2 : Node_Id;
  98       Node3 : Node_Id;
  99       Node4 : Node_Id;
 100       Node5 : Node_Id;
 101       Node6 : Node_Id) return List_Id;
 102    --  Build a new list initially containing the six given nodes
 103
 104    function New_Copy_List (List : List_Id) return List_Id;
 105    --  Creates a new list containing copies (made with Atree.New_Copy) of every
 106    --  node in the original list. If the argument is No_List, then the returned
 107    --  result is No_List. If the argument is an empty list, then the returned
 108    --  result is a new empty list.
 109
 110    function New_Copy_List_Original (List : List_Id) return List_Id;
 111    --  Same as New_Copy_List but copies only nodes coming from source
 112
 113    function New_Copy_List_Tree (List : List_Id) return List_Id;
 114    --  Similar to New_Copy_List, except that the copies are done using the
 115    --  Atree.New_Copy_Tree function, which means that a full recursive copy
 116    --  of the subtrees in the list is performed, setting proper parents. As
 117    --  for New_Copy_Tree, it is illegal to attempt to copy extended nodes
 118    --  (entities) either directly or indirectly using this function.
 119
 120    function First (List : List_Id) return Node_Id;
 121    pragma Inline (First);
 122    --  Obtains the first element of the given node list or, if the node list
 123    --  has no items or is equal to No_List, then Empty is returned.
 124
 125    function First_Non_Pragma (List : List_Id) return Node_Id;
 126    --  Used when dealing with a list that can contain pragmas to skip past
 127    --  any initial pragmas and return the first element that is not a pragma.
 128    --  If the list is empty, or if it contains only pragmas, then Empty is
 129    --  returned. It is an error to call First_Non_Pragma with a Node_Id value
 130    --  or No_List (No_List is not considered to be the same as an empty list).
 131    --  This function also skips N_Null nodes which can result from rewriting
 132    --  unrecognized or incorrrect pragmas.
 133
 134    function Last (List : List_Id) return Node_Id;
 135    pragma Inline (Last);
 136    --  Obtains the last element of the given node list or, if the node list
 137    --  has no items, then Empty is returned. It is an error to call Last with
 138    --  a Node_Id or No_List. (No_List is not considered to be the same as an
 139    --  empty node list).
 140
 141    function Last_Non_Pragma (List : List_Id) return Node_Id;
 142    --  Obtains the last element of a given node list that is not a pragma.
 143    --  If the list is empty, or if it contains only pragmas, then Empty is
 144    --  returned. It is an error to call Last_Non_Pragma with a Node_Id or
 145    --  No_List. (No_List is not considered to be the same as an empty list).
 146
 147    function List_Length (List : List_Id) return Nat;
 148    pragma Inline (List_Length);
 149    --  Returns number of items in the given list. It is an error to call
 150    --  this function with No_List (No_List is not considered to be the same
 151    --  as an empty list).
 152
 153    function Next (Node : Node_Id) return Node_Id;
 154    pragma Inline (Next);
 155    --  This function returns the next node on a node list, or Empty if Node is
 156    --  the last element of the node list. The argument must be a member of a
 157    --  node list.
 158
 159    procedure Next (Node : in out Node_Id);
 160    pragma Inline (Next);
 161    --  Equivalent to Node := Next (Node);
 162
 163    function Next_Non_Pragma (Node : Node_Id) return Node_Id;
 164    --  This function returns the next node on a node list, skipping past any
 165    --  pragmas, or Empty if there is no non-pragma entry left. The argument
 166    --  must be a member of a node list. This function also skips N_Null nodes
 167    --  which can result from rewriting unrecognized or incorrect pragmas.
 168
 169    procedure Next_Non_Pragma (Node : in out Node_Id);
 170    pragma Inline (Next_Non_Pragma);
 171    --  Equivalent to Node := Next_Non_Pragma (Node);
 172
 173    function Prev (Node : Node_Id) return Node_Id;
 174    pragma Inline (Prev);
 175    --  This function returns the previous node on a node list list, or Empty
 176    --  if Node is the first element of the node list. The argument must be
 177    --  a member of a node list. Note: the implementation does maintain back
 178    --  pointers, so this function executes quickly in constant time.
 179
 180    function Pick (List : List_Id; Index : Pos) return Node_Id;
 181    --  Given a list, picks out the Index'th entry (1 = first entry). The
 182    --  caller must ensure that Index is in range.
 183
 184    procedure Prev (Node : in out Node_Id);
 185    pragma Inline (Prev);
 186    --  Equivalent to Node := Prev (Node);
 187
 188    function Prev_Non_Pragma (Node : Node_Id) return Node_Id;
 189    pragma Inline (Prev_Non_Pragma);
 190    --  This function returns the previous node on a node list, skipping any
 191    --  pragmas. If Node is the first element of the list, or if the only
 192    --  elements preceding it are pragmas, then Empty is returned. The
 193    --  argument must be a member of a node list. Note: the implementation
 194    --  does maintain back pointers, so this function executes quickly in
 195    --  constant time.
 196
 197    procedure Prev_Non_Pragma (Node : in out Node_Id);
 198    pragma Inline (Prev_Non_Pragma);
 199    --  Equivalent to Node := Prev_Non_Pragma (Node);
 200
 201    function Is_Empty_List (List : List_Id) return Boolean;
 202    pragma Inline (Is_Empty_List);
 203    --  This function determines if a given list id references a node list that
 204    --  contains no items. No_List is a not a legitimate argument.
 205
 206    function Is_Non_Empty_List (List : List_Id) return Boolean;
 207    pragma Inline (Is_Non_Empty_List);
 208    --  This function determines if a given list id references a node list that
 209    --  contains at least one item. No_List as an argument returns False.
 210
 211    function Is_List_Member (Node : Node_Id) return Boolean;
 212    pragma Inline (Is_List_Member);
 213    --  This function determines if a given node is a member of a node list.
 214    --  It is an error for Node to be Empty, or to be a node list.
 215
 216    function List_Containing (Node : Node_Id) return List_Id;
 217    pragma Inline (List_Containing);
 218    --  This function provides a pointer to the node list containing Node.
 219    --  Node must be a member of a node list.
 220
 221    procedure Append (Node : Node_Id; To : List_Id);
 222    --  Appends Node at the end of node list To. Node must be a non-empty node
 223    --  that is not already a member of a node list, and To must be a
 224    --  node list. An attempt to append an error node is ignored without
 225    --  complaint and the list is unchanged.
 226
 227    procedure Append_To (To : List_Id; Node : Node_Id);
 228    pragma Inline (Append_To);
 229    --  Like Append, but arguments are the other way round
 230
 231    procedure Append_List (List : List_Id; To : List_Id);
 232    --  Appends node list List to the end of node list To. On return,
 233    --  List is reset to be empty.
 234
 235    procedure Append_List_To (To : List_Id; List : List_Id);
 236    pragma Inline (Append_List_To);
 237    --  Like Append_List, but arguments are the other way round
 238
 239    procedure Insert_After (After : Node_Id; Node : Node_Id);
 240    --  Insert Node, which must be a non-empty node that is not already a
 241    --  member of a node list, immediately past node After, which must be a
 242    --  node that is currently a member of a node list. An attempt to insert
 243    --  an error node is ignored without complaint (and the list is unchanged).
 244
 245    procedure Insert_List_After (After : Node_Id; List : List_Id);
 246    --  Inserts the entire contents of node list List immediately after node
 247    --  After, which must be a member of a node list. On return, the node list
 248    --  List is reset to be the empty node list.
 249
 250    procedure Insert_Before (Before : Node_Id; Node : Node_Id);
 251    --  Insert Node, which must be a non-empty node that is not already a
 252    --  member of a node list, immediately before Before, which must be a node
 253    --  that is currently a member of a node list. An attempt to insert an
 254    --  error node is ignored without complaint (and the list is unchanged).
 255
 256    procedure Insert_List_Before (Before : Node_Id; List : List_Id);
 257    --  Inserts the entire contents of node list List immediately before node
 258    --  Before, which must be a member of a node list. On return, the node list
 259    --  List is reset to be the empty node list.
 260
 261    procedure Prepend (Node : Node_Id; To : List_Id);
 262    --  Prepends Node at the start of node list To. Node must be a non-empty
 263    --  node that is not already a member of a node list, and To must be a
 264    --  node list. An attempt to prepend an error node is ignored without
 265    --  complaint and the list is unchanged.
 266
 267    procedure Prepend_To (To : List_Id; Node : Node_Id);
 268    pragma Inline (Prepend_To);
 269    --  Like Prepend, but arguments are the other way round
 270
 271    procedure Remove (Node : Node_Id);
 272    --  Removes Node, which must be a node that is a member of a node list,
 273    --  from this node list. The contents of Node are not otherwise affected.
 274
 275    function Remove_Head (List : List_Id) return Node_Id;
 276    --  Removes the head element of a node list, and returns the node (whose
 277    --  contents are not otherwise affected) as the result. If the node list
 278    --  is empty, then Empty is returned.
 279
 280    function Remove_Next (Node : Node_Id) return Node_Id;
 281    --  Removes the item immediately following the given node, and returns it
 282    --  as the result. If Node is the last element of the list, then Empty is
 283    --  returned. Node must be a member of a list. Unlike Remove, Remove_Next
 284    --  is fast and does not involve any list traversal.
 285
 286    procedure Initialize;
 287    --  Called at the start of compilation of each new main source file to
 288    --  initialize the allocation of the list table. Note that Initialize
 289    --  must not be called if Tree_Read is used.
 290
 291    procedure Lock;
 292    --  Called to lock tables before back end is called
 293
 294    procedure Tree_Read;
 295    --  Initializes internal tables from current tree file using the relevant
 296    --  Table.Tree_Read routines. Note that Initialize should not be called if
 297    --  Tree_Read is used. Tree_Read includes all necessary initialization.
 298
 299    procedure Tree_Write;
 300    --  Writes out internal tables to current tree file using the relevant
 301    --  Table.Tree_Write routines.
 302
 303    function Parent (List : List_Id) return Node_Id;
 304    pragma Inline (Parent);
 305    --  Node lists may have a parent in the same way as a node. The function
 306    --  accesses the Parent value, which is either Empty when a list header
 307    --  is first created, or the value that has been set by Set_Parent.
 308
 309    procedure Set_Parent (List : List_Id; Node : Node_Id);
 310    pragma Inline (Set_Parent);
 311    --  Sets the parent field of the given list to reference the given node
 312
 313    function No (List : List_Id) return Boolean;
 314    pragma Inline (No);
 315    --  Tests given Id for equality with No_List. This allows notations like
 316    --  "if No (Statements)" as opposed to "if Statements = No_List".
 317
 318    function Present (List : List_Id) return Boolean;
 319    pragma Inline (Present);
 320    --  Tests given Id for inequality with No_List. This allows notations like
 321    --  "if Present (Statements)" as opposed to "if Statements /= No_List".
 322
 323    procedure Allocate_List_Tables (N : Node_Id);
 324    --  Called when nodes table is expanded to include node N. This call
 325    --  makes sure that list structures internal to Nlists are adjusted
 326    --  appropriately to reflect this increase in the size of the nodes table.
 327
 328    function Next_Node_Address return System.Address;
 329    function Prev_Node_Address return System.Address;
 330    --  These functions return the addresses of the Next_Node and Prev_Node
 331    --  tables (used in Back_End for Gigi).
 332
 333    procedure Delete_List (L : List_Id);
 334    --  Removes all elements of the given list, and calls Delete_Tree on each
 335
 336    function p (U : Union_Id) return Node_Id;
 337    --  This function is intended for use from the debugger, it determines
 338    --  whether U is a Node_Id or List_Id, and calls the appropriate Parent
 339    --  function and returns the parent Node in either case. This is shorter
 340    --  to type, and avoids the overloading problem of using Parent. It
 341    --  should NEVER be used except from the debugger. If p is called with
 342    --  other than a node or list id value, it returns 99_999_999.
 343
 344 end Nlists;