diff options
| -rw-r--r-- | src/synth/netlists-cleanup.adb | 107 | ||||
| -rw-r--r-- | src/synth/netlists-cleanup.ads | 26 | ||||
| -rw-r--r-- | src/synth/netlists-utils.adb | 59 | ||||
| -rw-r--r-- | src/synth/netlists-utils.ads | 7 | ||||
| -rw-r--r-- | src/synth/netlists.adb | 40 | ||||
| -rw-r--r-- | src/synth/netlists.ads | 13 | ||||
| -rw-r--r-- | src/synth/synth-insts.adb | 4 |
7 files changed, 188 insertions, 68 deletions
diff --git a/src/synth/netlists-cleanup.adb b/src/synth/netlists-cleanup.adb new file mode 100644 index 000000000..207a8a63e --- /dev/null +++ b/src/synth/netlists-cleanup.adb @@ -0,0 +1,107 @@ +-- Netlist cleanup. +-- Copyright (C) 2019 Tristan Gingold +-- +-- This file is part of GHDL. +-- +-- This program 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 of the License, or +-- (at your option) any later version. +-- +-- This program 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 this program; if not, write to the Free Software +-- Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, +-- MA 02110-1301, USA. + +with Netlists.Utils; use Netlists.Utils; + +package body Netlists.Cleanup is + function Is_Unused_Instance (Inst : Instance) return Boolean + is + Nbr_Outputs : constant Port_Idx := Get_Nbr_Outputs (Inst); + N : Net; + begin + -- An instance without outputs is considered as used. + if Nbr_Outputs = 0 then + return Get_Module (Inst) = Free_Module; + end if; + + for Idx in 0 .. Nbr_Outputs - 1 loop + N := Get_Output (Inst, Idx); + if Is_Connected (N) then + -- Connected output. + return False; + end if; + end loop; + + -- All outputs are unconnected. + return True; + end Is_Unused_Instance; + + procedure Extract_If_Unused (Inst : Instance; List : in out Instance) is + begin + if Is_Unused_Instance (Inst) then + Extract_Instance (Inst); + Set_Next_Instance (Inst, List); + List := Inst; + end if; + end Extract_If_Unused; + + -- TODO: use mark & sweep to remove unused assignments ? + procedure Remove_Unconnected_Instances (M : Module) + is + Inst : Instance; + Next_Inst : Instance; + List : Instance; + begin + -- Extract from instances of M all unconnected instances. Put them + -- in a list. + List := No_Instance; + + Inst := Get_First_Instance (M); + while Inst /= No_Instance loop + Next_Inst := Get_Next_Instance (Inst); + Extract_If_Unused (Inst, List); + Inst := Next_Inst; + end loop; + + -- While the list is not empty: + -- extract the first instance of the list. + -- unconnect all inputs of the instance, free the instance. + -- if unconnected an input resulted in an instance without connected + -- output, extract it from M and append it in the list. + while List /= No_Instance loop + Inst := List; + List := Get_Next_Instance (Inst); + + declare + Nbr_Inputs : constant Port_Nbr := Get_Nbr_Inputs (Inst); + Inp : Input; + Drv : Net; + Inst2 : Instance; + begin + if Nbr_Inputs > 0 then + for K in 0 .. Nbr_Inputs - 1 loop + Inp := Get_Input (Inst, K); + Drv := Get_Driver (Inp); + if Drv /= No_Net then + -- The input was already unconnected. + Disconnect (Inp); + if Get_First_Sink (Drv) = No_Input then + Inst2 := Get_Net_Parent (Drv); + Extract_If_Unused (Inst2, List); + end if; + end if; + end loop; + end if; + end; + + Free_Instance (Inst); + end loop; + end Remove_Unconnected_Instances; +end Netlists.Cleanup; diff --git a/src/synth/netlists-cleanup.ads b/src/synth/netlists-cleanup.ads new file mode 100644 index 000000000..7f373130d --- /dev/null +++ b/src/synth/netlists-cleanup.ads @@ -0,0 +1,26 @@ +-- Netlist cleanup. +-- Copyright (C) 2019 Tristan Gingold +-- +-- This file is part of GHDL. +-- +-- This program 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 of the License, or +-- (at your option) any later version. +-- +-- This program 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 this program; if not, write to the Free Software +-- Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, +-- MA 02110-1301, USA. + +package Netlists.Cleanup is + -- Remove instances of module M whose outputs are not connected. + -- Their inputs will be deconnected, which can result in new instances + -- that are also removed. + procedure Remove_Unconnected_Instances (M : Module); +end Netlists.Cleanup; diff --git a/src/synth/netlists-utils.adb b/src/synth/netlists-utils.adb index 02e1ea24a..d5a1f2edd 100644 --- a/src/synth/netlists-utils.adb +++ b/src/synth/netlists-utils.adb @@ -175,63 +175,4 @@ package body Netlists.Utils is -- Free Inst Free_Instance (Inst); end Disconnect_And_Free; - - function Is_Unused_Instance (Inst : Instance) return Boolean - is - Nbr_Outputs : constant Port_Idx := Get_Nbr_Outputs (Inst); - N : Net; - begin - -- An instance without outputs is considered as used. - if Nbr_Outputs = 0 then - return False; - end if; - - for Idx in 0 .. Nbr_Outputs - 1 loop - N := Get_Output (Inst, Idx); - if Is_Connected (N) then - -- Connected output. - return False; - end if; - end loop; - - -- All outputs are unconnected. - return True; - end Is_Unused_Instance; - - procedure Remove_Unused_Instances (M : Module) - is - pragma Assert (Is_Valid (M)); - Inst : Instance; - begin - Extract_All_Instances (M, Inst); - - -- Add the self instance (the first one). - Append_Instance (M, Inst); - Inst := Get_Next_Instance (Inst); - - while Inst /= No_Instance loop - if not (Get_Id (Inst) = Id_Free - or else Is_Unused_Instance (Inst)) - then - -- Keep this used instance. - Append_Instance (M, Inst); - end if; - Inst := Get_Next_Instance (Inst); - end loop; - end Remove_Unused_Instances; - - procedure Remove_Free_Instances (M : Module) - is - pragma Assert (Is_Valid (M)); - Inst : Instance; - begin - Extract_All_Instances (M, Inst); - - while Inst /= No_Instance loop - if Get_Id (Inst) /= Id_Free then - Append_Instance (M, Inst); - end if; - Inst := Get_Next_Instance (Inst); - end loop; - end Remove_Free_Instances; end Netlists.Utils; diff --git a/src/synth/netlists-utils.ads b/src/synth/netlists-utils.ads index 165e986d8..10406500d 100644 --- a/src/synth/netlists-utils.ads +++ b/src/synth/netlists-utils.ads @@ -56,11 +56,4 @@ package Netlists.Utils is -- Disconnect input I. If the driver of I has no output(s) connected, -- disconnect and free it. procedure Disconnect_And_Free (I : Input); - - -- Unlink all free instances of M. - procedure Remove_Free_Instances (M : Module); - - -- Unlink all unused instances of M. - procedure Remove_Unused_Instances (M : Module); - end Netlists.Utils; diff --git a/src/synth/netlists.adb b/src/synth/netlists.adb index 6597be8ed..b152dccd5 100644 --- a/src/synth/netlists.adb +++ b/src/synth/netlists.adb @@ -322,9 +322,35 @@ package body Netlists is else Instances_Table.Table (M_Ent.Last_Instance).Next_Instance := Inst; end if; + Instances_Table.Table (Inst).Prev_Instance := M_Ent.Last_Instance; M_Ent.Last_Instance := Inst; end Append_Instance; + procedure Extract_Instance (Inst : Instance) + is + pragma Assert (Is_Valid (Inst)); + Inst_Ent : Instance_Record renames Instances_Table.Table (Inst); + M : constant Module := Inst_Ent.Parent; + M_Ent : Module_Record renames Modules_Table.Table (M); + begin + if Inst_Ent.Prev_Instance /= No_Instance then + Set_Next_Instance (Inst_Ent.Prev_Instance, Inst_Ent.Next_Instance); + else + pragma Assert (M_Ent.First_Instance = Inst); + M_Ent.First_Instance := Inst_Ent.Next_Instance; + end if; + + if Inst_Ent.Next_Instance /= No_Instance then + Set_Prev_Instance (Inst_Ent.Next_Instance, Inst_Ent.Prev_Instance); + else + pragma Assert (M_Ent.Last_Instance = Inst); + M_Ent.Last_Instance := Inst_Ent.Prev_Instance; + end if; + + Inst_Ent.Prev_Instance := No_Instance; + Inst_Ent.Next_Instance := No_Instance; + end Extract_Instance; + function New_Instance_Internal (Parent : Module; M : Module; Name : Sname; @@ -343,6 +369,7 @@ package body Netlists is begin Instances_Table.Append ((Parent => Parent, Next_Instance => No_Instance, + Prev_Instance => No_Instance, Klass => M, Name => Name, First_Param => Params, @@ -491,6 +518,18 @@ package body Netlists is return Instances_Table.Table (Inst).Next_Instance; end Get_Next_Instance; + procedure Set_Next_Instance (Inst : Instance; Next : Instance) is + begin + pragma Assert (Is_Valid (Inst)); + Instances_Table.Table (Inst).Next_Instance := Next; + end Set_Next_Instance; + + procedure Set_Prev_Instance (Inst : Instance; Prev : Instance) is + begin + pragma Assert (Is_Valid (Inst)); + Instances_Table.Table (Inst).Prev_Instance := Prev; + end Set_Prev_Instance; + function Get_First_Output (Inst : Instance) return Net is begin pragma Assert (Is_Valid (Inst)); @@ -831,6 +870,7 @@ begin Instances_Table.Append ((Parent => No_Module, Next_Instance => No_Instance, + Prev_Instance => No_Instance, Klass => No_Module, Name => No_Sname, First_Param => No_Param_Idx, diff --git a/src/synth/netlists.ads b/src/synth/netlists.ads index 4580edb89..c1371c835 100644 --- a/src/synth/netlists.ads +++ b/src/synth/netlists.ads @@ -320,7 +320,9 @@ private -- Sub-module brother. Next_Sub_Module : Module; + -- List of instances. -- The self instance is the first instance. + -- FIXME: use an array instead ? First_Instance : Instance; Last_Instance : Instance; end record; @@ -337,6 +339,9 @@ private type Instance_Record is record -- The instance is instantiated in Parent. Parent : Module; + + -- Instances are in a doubly-linked list. + Prev_Instance : Instance; Next_Instance : Instance; -- For a self-instance, Klass is equal to Parent, and Name is No_Sname. @@ -348,6 +353,9 @@ private First_Output : Net; end record; + procedure Set_Next_Instance (Inst : Instance; Next : Instance); + procedure Set_Prev_Instance (Inst : Instance; Prev : Instance); + -- Procedures to rewrite the list of instances of a module: -- * first extract the chain of instances from module M (and reset the -- list of instances - so there is none), @@ -356,6 +364,11 @@ private procedure Extract_All_Instances (M : Module; First_Instance : out Instance); procedure Append_Instance (M : Module; Inst : Instance); + -- Extract INST from the list of instance of its module. + -- Will still be connected, but won't appear anymore in the list of + -- instances. + procedure Extract_Instance (Inst : Instance); + type Input is new Uns32; No_Input : constant Input := 0; diff --git a/src/synth/synth-insts.adb b/src/synth/synth-insts.adb index f2d67b4d7..c636cc497 100644 --- a/src/synth/synth-insts.adb +++ b/src/synth/synth-insts.adb @@ -27,7 +27,7 @@ with Std_Names; with Netlists; use Netlists; with Netlists.Builders; -with Netlists.Utils; +with Netlists.Cleanup; with Vhdl.Utils; use Vhdl.Utils; with Vhdl.Errors; @@ -916,7 +916,7 @@ package body Synth.Insts is -- a correctness point: there might be some unsynthesizable gates, like -- the one created for 'rising_egde (clk) and not rst'. if not Flags.Flag_Debug_Nocleanup then - Netlists.Utils.Remove_Unused_Instances + Netlists.Cleanup.Remove_Unconnected_Instances (Get_Instance_Module (Syn_Inst)); end if; end Synth_Instance; |