From 3a8482652759411ed2dfc837c3cc6f98ae032158 Mon Sep 17 00:00:00 2001 From: Tristan Gingold Date: Mon, 6 May 2019 21:58:47 +0200 Subject: vhdl: renames iir_chains to vhdl.nodes_utils. Remove iir_chain_handling. --- src/vhdl/vhdl-nodes_utils.ads | 82 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 src/vhdl/vhdl-nodes_utils.ads (limited to 'src/vhdl/vhdl-nodes_utils.ads') diff --git a/src/vhdl/vhdl-nodes_utils.ads b/src/vhdl/vhdl-nodes_utils.ads new file mode 100644 index 000000000..ef71e504b --- /dev/null +++ b/src/vhdl/vhdl-nodes_utils.ads @@ -0,0 +1,82 @@ +-- Chain handling. +-- Copyright (C) 2002, 2003, 2004, 2005 Tristan Gingold +-- +-- GHDL is free software; you can redistribute it and/or modify it under +-- the terms of the GNU General Public License as published by the Free +-- Software Foundation; either version 2, or (at your option) any later +-- version. +-- +-- GHDL is distributed in the hope that it will be useful, but WITHOUT 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 +-- along with GHDL; see the file COPYING. If not, write to the Free +-- Software Foundation, 59 Temple Place - Suite 330, Boston, MA +-- 02111-1307, USA. +with Vhdl.Nodes; use Vhdl.Nodes; +with Vhdl.Nodes_Meta; + +package Vhdl.Nodes_Utils is + -- Chains are simply linked list of iirs. + -- Elements of the chain are ordered. + -- Each element of a chain have a Chain field, which points to the next + -- element. + -- All elements of a chain have the same parent. This parent contains + -- a field which points to the first element of the chain. + -- Note: the parent is often the value of the Parent field, but sometimes + -- not. + + -- Chains can be covered very simply: + -- El : Iir; + -- begin + -- El := Get_xxx_Chain (Parent); + -- while El /= Null_Iir loop + -- * Handle element EL of the chain. + -- El := Get_Chain (El); + -- end loop; + + -- However, building a chain is a little bit more difficult if elements + -- have to be appended. Indeed, there is no direct access to the last + -- element of a chain. + -- An efficient way to build a chain is to keep the last element of it. + + -- Return the number of elements in a chain starting with FIRST. + -- Not very efficient since O(N). + function Get_Chain_Length (First : Iir) return Natural; + + -- Append CHAIN to the chain FIELD of node N. Not very efficient. + procedure Append_Chain + (N : Iir; Field : Vhdl.Nodes_Meta.Fields_Enum; Chain : Iir); + + -- These two subprograms can be used to build a sub-chain. + -- FIRST and LAST designates respectively the first and last element of + -- the sub-chain. + + -- Set FIRST and LAST to Null_Iir. + procedure Sub_Chain_Init (First, Last : out Iir); + pragma Inline (Sub_Chain_Init); + + -- Append element EL to the sub-chain. + procedure Sub_Chain_Append (First, Last : in out Iir; El : Iir); + pragma Inline (Sub_Chain_Append); + + -- Append chain to the sub-chain. FIRST_SUB and LAST_SUB must not be + -- Null_Iir. + procedure Sub_Chain_Append_Chain (First, Last : in out Iir; + First_Sub, Last_Sub : Iir); + procedure Sub_Chain_Append_Subchain (First, Last : in out Iir; + Sub : Iir); + + -- Return TRUE iff CHAIN is of length one, ie CHAIN is not NULL_IIR + -- and chain (CHAIN) is NULL_IIR. + function Is_Chain_Length_One (Chain : Iir) return Boolean; + pragma Inline (Is_Chain_Length_One); + + -- Insert EL after LAST. + procedure Insert (Last : Iir; El : Iir); + + -- Insert EL after LAST and set LAST to EL. + procedure Insert_Incr (Last : in out Iir; El : Iir); +end Vhdl.Nodes_Utils; -- cgit v1.2.3