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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- N L I S T S --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2022, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING3. If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This package provides facilities for manipulating lists of nodes (see
-- package Atree for format and implementation of tree nodes). The Link field
-- of the nodes is used as the forward pointer for these lists. See also
-- package Elists which provides another form of lists that are not threaded
-- through the nodes (and therefore allow nodes to be on multiple lists).
-- WARNING: There is a C version of this package. Any changes to this
-- source file must be properly reflected in the C header file nlists.h
with System;
with Types; use Types;
package Nlists is
-- A node list is a list of nodes in a special format that means that
-- nodes can be on at most one such list. For each node list, a list
-- header is allocated in the lists table, and a List_Id value references
-- this header, which may be used to access the nodes in the list using
-- the set of routines that define this interface.
-- Note: node lists can contain either nodes or entities (extended nodes)
-- or a mixture of nodes and extended nodes.
function In_Same_List (N1, N2 : Node_Or_Entity_Id) return Boolean;
pragma Inline (In_Same_List);
-- Equivalent to List_Containing (N1) = List_Containing (N2)
function Last_List_Id return List_Id;
pragma Inline (Last_List_Id);
-- Returns Id of last allocated list header
function Lists_Address return System.Address;
pragma Inline (Lists_Address);
-- Return address of Lists table (used in Back_End for Gigi call)
function Num_Lists return Nat;
pragma Inline (Num_Lists);
-- Number of currently allocated lists
function New_List return List_Id;
-- Creates a new empty node list. Typically this is used to initialize
-- a field in some other node which points to a node list where the list
-- is then subsequently filled in using Append calls.
function Empty_List return List_Id renames New_List;
-- Used in contexts where an empty list (as opposed to an initially empty
-- list to be filled in) is required.
function New_List
(Node : Node_Or_Entity_Id) return List_Id;
-- Build a new list initially containing the given node
function New_List
(Node1 : Node_Or_Entity_Id;
Node2 : Node_Or_Entity_Id) return List_Id;
-- Build a new list initially containing the two given nodes
function New_List
(Node1 : Node_Or_Entity_Id;
Node2 : Node_Or_Entity_Id;
Node3 : Node_Or_Entity_Id) return List_Id;
-- Build a new list initially containing the three given nodes
function New_List
(Node1 : Node_Or_Entity_Id;
Node2 : Node_Or_Entity_Id;
Node3 : Node_Or_Entity_Id;
Node4 : Node_Or_Entity_Id) return List_Id;
function New_List
(Node1 : Node_Or_Entity_Id;
Node2 : Node_Or_Entity_Id;
Node3 : Node_Or_Entity_Id;
Node4 : Node_Or_Entity_Id;
Node5 : Node_Or_Entity_Id) return List_Id;
-- Build a new list initially containing the five given nodes
function New_List
(Node1 : Node_Or_Entity_Id;
Node2 : Node_Or_Entity_Id;
Node3 : Node_Or_Entity_Id;
Node4 : Node_Or_Entity_Id;
Node5 : Node_Or_Entity_Id;
Node6 : Node_Or_Entity_Id) return List_Id;
-- Build a new list initially containing the six given nodes
function New_Copy_List (List : List_Id) return List_Id;
-- Creates a new list containing copies (made with Atree.New_Copy) of every
-- node in the original list. If the argument is No_List, then the returned
-- result is No_List. If the argument is an empty list, then the returned
-- result is a new empty list.
function New_Copy_List_Original (List : List_Id) return List_Id;
-- Same as New_Copy_List but copies only nodes coming from source
function First (List : List_Id) return Node_Or_Entity_Id;
pragma Inline (First);
-- Obtains the first element of the given node list or, if the node list
-- has no items or is equal to No_List, then Empty is returned.
function First_Non_Pragma (List : List_Id) return Node_Or_Entity_Id;
-- Used when dealing with a list that can contain pragmas to skip past
-- any initial pragmas and return the first element that is not a pragma.
-- If the list is empty, or if it contains only pragmas, then Empty is
-- returned. It is an error to call First_Non_Pragma with a Node_Id value
-- or No_List (No_List is not considered to be the same as an empty list).
-- This function also skips N_Null nodes which can result from rewriting
-- unrecognized or incorrect pragmas.
function Last (List : List_Id) return Node_Or_Entity_Id;
pragma Inline (Last);
-- Obtains the last element of the given node list or, if the node list
-- has no items, then Empty is returned. It is an error to call Last with
-- a Node_Id or No_List. (No_List is not considered to be the same as an
-- empty node list).
function Last_Non_Pragma (List : List_Id) return Node_Or_Entity_Id;
-- Obtains the last element of a given node list that is not a pragma.
-- If the list is empty, or if it contains only pragmas, then Empty is
-- returned. It is an error to call Last_Non_Pragma with a Node_Id or
-- No_List. (No_List is not considered to be the same as an empty list).
function List_Length (List : List_Id) return Nat;
-- Returns number of items in the given list. If called on No_List it
-- returns 0, even though No_List is not considered to be the same as an
-- empty list.
function Next (Node : Node_Or_Entity_Id) return Node_Or_Entity_Id;
pragma Inline (Next);
-- This function returns the next node on a node list, or Empty if Node is
-- the last element of the node list. The argument must be a member of a
-- node list.
procedure Next (Node : in out Node_Or_Entity_Id);
pragma Inline (Next);
-- Equivalent to Node := Next (Node);
function Next_Non_Pragma
(Node : Node_Or_Entity_Id) return Node_Or_Entity_Id;
-- This function returns the next node on a node list, skipping past any
-- pragmas, or Empty if there is no non-pragma entry left. The argument
-- must be a member of a node list. This function also skips N_Null nodes
-- which can result from rewriting unrecognized or incorrect pragmas.
procedure Next_Non_Pragma (Node : in out Node_Or_Entity_Id);
pragma Inline (Next_Non_Pragma);
-- Equivalent to Node := Next_Non_Pragma (Node);
function Prev (Node : Node_Or_Entity_Id) return Node_Or_Entity_Id;
pragma Inline (Prev);
-- This function returns the previous node on a node list, or Empty
-- if Node is the first element of the node list. The argument must be
-- a member of a node list. Note: the implementation does maintain back
-- pointers, so this function executes quickly in constant time.
function Pick (List : List_Id; Index : Pos) return Node_Or_Entity_Id;
-- Given a list, picks out the Index'th entry (1 = first entry). The
-- caller must ensure that Index is in range.
procedure Prev (Node : in out Node_Or_Entity_Id);
pragma Inline (Prev);
-- Equivalent to Node := Prev (Node);
function Prev_Non_Pragma
(Node : Node_Or_Entity_Id) return Node_Or_Entity_Id;
pragma Inline (Prev_Non_Pragma);
-- This function returns the previous node on a node list, skipping any
-- pragmas. If Node is the first element of the list, or if the only
-- elements preceding it are pragmas, then Empty is returned. The
-- argument must be a member of a node list. Note: the implementation
-- does maintain back pointers, so this function executes quickly in
-- constant time.
procedure Prev_Non_Pragma (Node : in out Node_Or_Entity_Id);
pragma Inline (Prev_Non_Pragma);
-- Equivalent to Node := Prev_Non_Pragma (Node);
function Is_Empty_List (List : List_Id) return Boolean;
pragma Inline (Is_Empty_List);
-- This function determines if a given list id references a node list that
-- contains no items. No_List as an argument returns True.
function Is_Non_Empty_List (List : List_Id) return Boolean;
pragma Inline (Is_Non_Empty_List);
-- This function determines if a given list id references a node list that
-- contains at least one item. No_List as an argument returns False.
function Is_List_Member (Node : Node_Or_Entity_Id) return Boolean;
pragma Inline (Is_List_Member);
-- This function determines if a given node is a member of a node list.
-- It is an error for Node to be Empty, or to be a node list.
function List_Containing (Node : Node_Or_Entity_Id) return List_Id;
pragma Inline (List_Containing);
-- This function provides a pointer to the node list containing Node.
-- Node must be a member of a node list.
procedure Append (Node : Node_Or_Entity_Id; To : List_Id);
-- Appends Node at the end of node list To. Node must be a non-empty node
-- that is not already a member of a node list, and To must be a node list.
-- An attempt to append an error node is ignored without complaint and the
-- list is unchanged.
procedure Append_New (Node : Node_Or_Entity_Id; To : in out List_Id);
pragma Inline (Append_New);
-- Appends Node at the end of node list To. If To is non-existent list, a
-- list is created. Node must be a non-empty node that is not already a
-- member of a node list, and To must be a node list.
procedure Append_New_To (To : in out List_Id; Node : Node_Or_Entity_Id);
pragma Inline (Append_New_To);
-- Like Append_New, but the arguments are in reverse order
procedure Append_To (To : List_Id; Node : Node_Or_Entity_Id);
pragma Inline (Append_To);
-- Like Append, but arguments are the other way round
procedure Append_List (List : List_Id; To : List_Id);
-- Appends node list List to the end of node list To. On return,
-- List is reset to be empty.
procedure Append_List_To (To : List_Id; List : List_Id);
pragma Inline (Append_List_To);
-- Like Append_List, but arguments are the other way round
procedure Insert_After
(After : Node_Or_Entity_Id;
Node : Node_Or_Entity_Id);
-- Insert Node, which must be a non-empty node that is not already a
-- member of a node list, immediately past node After, which must be a
-- node that is currently a member of a node list. An attempt to insert
-- an error node is ignored without complaint (and the list is unchanged).
procedure Insert_List_After
(After : Node_Or_Entity_Id;
List : List_Id);
-- Inserts the entire contents of node list List immediately after node
-- After, which must be a member of a node list. On return, the node list
-- List is reset to be the empty node list.
procedure Insert_Before
(Before : Node_Or_Entity_Id;
Node : Node_Or_Entity_Id);
-- Insert Node, which must be a non-empty node that is not already a
-- member of a node list, immediately before Before, which must be a node
-- that is currently a member of a node list. An attempt to insert an
-- error node is ignored without complaint (and the list is unchanged).
procedure Insert_List_Before
(Before : Node_Or_Entity_Id;
List : List_Id);
-- Inserts the entire contents of node list List immediately before node
-- Before, which must be a member of a node list. On return, the node list
-- List is reset to be the empty node list.
procedure Prepend
(Node : Node_Or_Entity_Id;
To : List_Id);
-- Prepends Node at the start of node list To. Node must be a non-empty
-- node that is not already a member of a node list, and To must be a
-- node list. An attempt to prepend an error node is ignored without
-- complaint and the list is unchanged.
procedure Prepend_List
(List : List_Id;
To : List_Id);
-- Prepends node list List to the start of node list To. On return,
-- List is reset to be empty.
procedure Prepend_List_To
(To : List_Id;
List : List_Id);
pragma Inline (Prepend_List_To);
-- Like Prepend_List, but arguments are the other way round
procedure Prepend_New (Node : Node_Or_Entity_Id; To : in out List_Id);
pragma Inline (Prepend_New);
-- Prepends Node at the end of node list To. If To is non-existent list, a
-- list is created. Node must be a non-empty node that is not already a
-- member of a node list, and To must be a node list.
procedure Prepend_New_To (To : in out List_Id; Node : Node_Or_Entity_Id);
pragma Inline (Prepend_New_To);
-- Like Prepend_New, but the arguments are in reverse order
procedure Prepend_To
(To : List_Id;
Node : Node_Or_Entity_Id);
pragma Inline (Prepend_To);
-- Like Prepend, but arguments are the other way round
procedure Remove (Node : Node_Or_Entity_Id);
-- Removes Node, which must be a node that is a member of a node list,
-- from this node list. The contents of Node are not otherwise affected.
function Remove_Head (List : List_Id) return Node_Or_Entity_Id;
-- Removes the head element of a node list, and returns the node (whose
-- contents are not otherwise affected) as the result. If the node list
-- is empty, then Empty is returned.
function Remove_Next (Node : Node_Or_Entity_Id) return Node_Or_Entity_Id;
-- Removes the item immediately following the given node, and returns it
-- as the result. If Node is the last element of the list, then Empty is
-- returned. Node must be a member of a list. Unlike Remove, Remove_Next
-- is fast and does not involve any list traversal.
procedure Initialize;
-- Called at the start of compilation of each new main source file to
-- initialize the allocation of the list table.
procedure Lock;
-- Called to lock tables before back end is called
procedure Lock_Lists;
-- Called to lock list contents when assertions are enabled. Without
-- assertions calling this subprogram has no effect. The initial state
-- of the lock is unlocked.
procedure Unlock;
-- Unlock tables, in cases where the back end needs to modify them
procedure Unlock_Lists;
-- Called to unlock list contents when assertions are enabled; if
-- assertions are not enabled calling this subprogram has no effect.
function Parent (List : List_Id) return Node_Or_Entity_Id;
pragma Inline (Parent);
-- Node lists may have a parent in the same way as a node. The function
-- accesses the Parent value, which is either Empty when a list header
-- is first created, or the value that has been set by Set_Parent.
procedure Set_Parent (List : List_Id; Node : Node_Or_Entity_Id);
pragma Inline (Set_Parent);
-- Sets the parent field of the given list to reference the given node
function No (List : List_Id) return Boolean;
pragma Inline (No);
-- Tests given Id for equality with No_List. This allows notations like
-- "if No (Statements)" as opposed to "if Statements = No_List". Note that
-- an empty list gives False for this test, as opposed to Is_Empty_List
-- which gives True either for No_List or for an empty list.
function Present (List : List_Id) return Boolean;
pragma Inline (Present);
-- Tests given Id for inequality with No_List. This allows notations like
-- "if Present (Statements)" as opposed to "if Statements /= No_List".
procedure Allocate_List_Tables (N : Node_Or_Entity_Id);
pragma Inline (Allocate_List_Tables);
-- Called when nodes table is expanded to include node N. This call
-- makes sure that list structures internal to Nlists are adjusted
-- appropriately to reflect this increase in the size of the nodes table.
function Next_Node_Address return System.Address;
function Prev_Node_Address return System.Address;
-- These functions return the addresses of the Next_Node and Prev_Node
-- tables (used in Back_End for Gigi).
end Nlists;