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403 lines
14 KiB
ObjectPascal
403 lines
14 KiB
ObjectPascal
{
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Copyright (c) 1998-2004 by Jonas Maebe, member of the Free Pascal
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Development Team
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This unit contains the interface routines between the code generator
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and the optimizer.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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****************************************************************************
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}
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Unit aopt;
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{$i fpcdefs.inc}
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{ $define DEBUG_OPTALLOC}
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{ $define DEBUG_INSTRUCTIONREGISTERDEPENDENCIES}
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Interface
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Uses
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aasmbase,aasmtai,aasmdata,aasmcpu,
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aoptobj;
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Type
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TAsmOptimizer = class(TAoptObj)
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{ _AsmL is the PAasmOutpout list that has to be optimized }
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Constructor create(_AsmL: TAsmList); virtual; reintroduce;
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{ call the necessary optimizer procedures }
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Procedure Optimize;virtual;
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Destructor destroy;override;
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private
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procedure FindLoHiLabels;
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{ Builds a table with the locations of the labels in the TAsmList.
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Also fixes some RegDeallocs like "# %eax released; push (%eax)" }
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Procedure BuildLabelTableAndFixRegAlloc;
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procedure clear;
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protected
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procedure pass_1;
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End;
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TAsmOptimizerClass = class of TAsmOptimizer;
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TAsmScheduler = class(TAoptObj)
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{ _AsmL is the PAasmOutpout list that has to be re-scheduled }
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Constructor Create(_AsmL: TAsmList); virtual; reintroduce;
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Procedure Optimize;
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function SchedulerPass1Cpu(var p: tai): boolean; virtual; abstract;
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procedure SchedulerPass1;
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end;
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TAsmSchedulerClass = class of TAsmScheduler;
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var
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casmoptimizer : TAsmOptimizerClass;
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cpreregallocscheduler : TAsmSchedulerClass;
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procedure Optimize(AsmL:TAsmList);
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procedure PreRegallocSchedule(AsmL:TAsmList);
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Implementation
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uses
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cutils,
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globtype, globals,
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verbose,
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cpubase,
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cgbase,
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aoptcpu;
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Constructor TAsmOptimizer.create(_AsmL: TAsmList);
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Begin
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inherited create(_asml,nil,nil,nil);
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{ setup labeltable, always necessary }
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New(LabelInfo);
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End;
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procedure TAsmOptimizer.FindLoHiLabels;
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{ Walks through the paasmlist to find the lowest and highest label number. }
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{ Returns the last Pai object of the current block }
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Var LabelFound: Boolean;
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p: tai;
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Begin
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LabelInfo^.LowLabel := High(longint);
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LabelInfo^.HighLabel := 0;
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LabelInfo^.LabelDif := 0;
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LabelInfo^.LabelTable:=nil;
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LabelFound := False;
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P := BlockStart;
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With LabelInfo^ Do
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Begin
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While Assigned(P) And
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((P.typ <> Ait_Marker) Or
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(tai_Marker(P).Kind <> mark_AsmBlockStart)) Do
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Begin
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If (p.typ = ait_label) and
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(tai_Label(p).labsym.labeltype=alt_jump) and
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(tai_Label(p).labsym.is_used) Then
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Begin
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LabelFound := True;
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If (tai_Label(p).labsym.labelnr < LowLabel) Then
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LowLabel := tai_Label(p).labsym.labelnr;
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If (tai_Label(p).labsym.labelnr > HighLabel) Then
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HighLabel := tai_Label(p).labsym.labelnr
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End;
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GetNextInstruction(p, p)
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End;
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blockend:=p;
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If LabelFound
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Then LabelDif := HighLabel-LowLabel+1
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Else LabelDif := 0
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End
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End;
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Procedure TAsmOptimizer.BuildLabelTableAndFixRegAlloc;
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Var p,hp1, hp2: tai;
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Regs: TAllUsedRegs;
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LabelIdx : longint;
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Begin
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CreateUsedRegs(Regs);
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With LabelInfo^ Do
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begin
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If (LabelDif <> 0) Then
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Begin
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GetMem(LabelTable, LabelDif*SizeOf(TLabelTableItem));
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FillChar(LabelTable^, LabelDif*SizeOf(TLabelTableItem), 0);
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end;
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p := BlockStart;
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While (P <> BlockEnd) Do
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Begin
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Case p.typ Of
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ait_Label:
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begin
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If tai_label(p).labsym.is_used and
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(tai_Label(p).labsym.labeltype=alt_jump) then
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begin
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LabelIdx:=tai_label(p).labsym.labelnr-LowLabel;
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if LabelIdx>int64(LabelDif) then
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internalerror(200604202);
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LabelTable^[LabelIdx].PaiObj := p;
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end;
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end;
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ait_regAlloc:
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begin
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if tai_regalloc(p).ratype=ra_alloc then
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Begin
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If Not(RegInUsedRegs(tai_regalloc(p).Reg,Regs)) Then
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IncludeRegInUsedRegs(tai_regalloc(p).Reg,Regs)
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Else
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Begin
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hp1 := tai(p.previous);
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{$ifdef DEBUG_OPTALLOC}
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AsmL.InsertAfter(tai_comment.Create(strpnew('Removed allocation of '+std_regname(tai_regalloc(p).Reg))),p);
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{$endif DEBUG_OPTALLOC}
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AsmL.remove(p);
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p.free;
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p := hp1;
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{ not sure if this is useful, it even skips previous deallocs of the register (FK)
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hp1 := p;
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hp2 := nil;
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While GetLastInstruction(hp1, hp1) And
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Not(RegInInstruction(tai_regalloc(p).Reg, hp1)) Do
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hp2:=hp1;
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If hp2<>nil Then
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Begin
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hp1:=tai_regalloc.DeAlloc(tai_regalloc(p).Reg,hp2);
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InsertLLItem(tai(hp2.previous), hp2, hp1);
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End;
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}
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End;
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End
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else if tai_regalloc(p).ratype=ra_dealloc then
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Begin
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ExcludeRegFromUsedRegs(tai_regalloc(p).Reg,Regs);
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hp1 := p;
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hp2 := nil;
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While Not(assigned(FindRegAlloc(tai_regalloc(p).Reg, tai(hp1.Next)))) And
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GetNextInstruction(hp1, hp1) And
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InstructionLoadsFromReg(tai_regalloc(p).Reg, hp1) Do
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hp2 := hp1;
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{ move deallocations }
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If hp2 <> nil Then
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Begin
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hp1 := tai(p.previous);
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{$ifdef DEBUG_OPTALLOC}
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AsmL.InsertAfter(tai_comment.Create(strpnew('Moved deallocation of '+std_regname(tai_regalloc(p).Reg))),p);
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{$endif DEBUG_OPTALLOC}
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AsmL.Remove(p);
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InsertLLItem(hp2, tai(hp2.Next), p);
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{ don't remove this deallocation later on when merging dealloc/alloc pairs because
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it marks indenpendent use of a register
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This could be also achieved by a separate passes for merging first and then later
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moving but I did not choose this solution because it takes more time and code (FK) }
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tai_regalloc(p).keep:=true;
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{$ifdef DEBUG_OPTALLOC}
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AsmL.InsertAfter(tai_comment.Create(strpnew('Moved deallocation of '+std_regname(tai_regalloc(p).Reg)+' here')),hp2);
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{$endif DEBUG_OPTALLOC}
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p := hp1;
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End
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{ merge allocations/deallocations }
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else if assigned(findregalloc(tai_regalloc(p).reg, tai(p.next)))
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and getnextinstruction(p,hp1) and
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{ don't merge deallocations/allocation which mark a new use of register, this
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enables more possibilities for the peephole optimizer }
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not(tai_regalloc(p).keep) then
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begin
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hp1 := tai(p.previous);
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{$ifdef DEBUG_OPTALLOC}
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AsmL.InsertAfter(tai_comment.Create(strpnew('Removed deallocation of '+std_regname(tai_regalloc(p).Reg))),p);
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{$endif DEBUG_OPTALLOC}
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AsmL.remove(p);
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p.free;
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p := hp1;
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end;
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End
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End
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End;
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P := tai(p.Next);
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While Assigned(p) and
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(p <> blockend) and
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(p.typ in (SkipInstr - [ait_regalloc])) Do
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P := tai(P.Next)
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End;
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end;
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ReleaseUsedRegs(Regs);
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End;
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procedure tasmoptimizer.clear;
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begin
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if assigned(LabelInfo^.labeltable) then
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begin
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freemem(LabelInfo^.labeltable);
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LabelInfo^.labeltable := nil;
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end;
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LabelInfo^.labeldif:=0;
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LabelInfo^.lowlabel:=high(longint);
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LabelInfo^.highlabel:=0;
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end;
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procedure tasmoptimizer.pass_1;
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begin
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findlohilabels;
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BuildLabelTableAndFixRegAlloc;
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end;
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Procedure TAsmOptimizer.Optimize;
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Var
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HP: tai;
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pass: longint;
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Begin
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pass:=0;
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BlockStart := tai(AsmL.First);
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pass_1;
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While Assigned(BlockStart) Do
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Begin
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if (cs_opt_peephole in current_settings.optimizerswitches) then
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begin
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if pass = 0 then
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PrePeepHoleOpts;
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{ Peephole optimizations }
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PeepHoleOptPass1;
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{ Only perform them twice in the first pass }
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if pass = 0 then
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PeepHoleOptPass1;
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end;
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{ more peephole optimizations }
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if (cs_opt_peephole in current_settings.optimizerswitches) then
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begin
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PeepHoleOptPass2;
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{ if pass = last_pass then }
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PostPeepHoleOpts;
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end;
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{ free memory }
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clear;
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{ continue where we left off, BlockEnd is either the start of an }
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{ assembler block or nil}
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BlockStart := BlockEnd;
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While Assigned(BlockStart) And
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(BlockStart.typ = ait_Marker) And
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(tai_Marker(BlockStart).Kind = mark_AsmBlockStart) Do
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Begin
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{ we stopped at an assembler block, so skip it }
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While GetNextInstruction(BlockStart, BlockStart) And
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((BlockStart.Typ <> Ait_Marker) Or
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(tai_Marker(Blockstart).Kind <> mark_AsmBlockEnd)) Do;
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{ blockstart now contains a tai_marker(mark_AsmBlockEnd) }
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If GetNextInstruction(BlockStart, HP) And
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((HP.typ <> ait_Marker) Or
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(Tai_Marker(HP).Kind <> mark_AsmBlockStart)) Then
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{ There is no assembler block anymore after the current one, so }
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{ optimize the next block of "normal" instructions }
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pass_1
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{ Otherwise, skip the next assembler block }
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else
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blockStart := hp;
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End
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End;
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End;
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Destructor TAsmOptimizer.Destroy;
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Begin
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if assigned(LabelInfo^.LabelTable) then
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Freemem(LabelInfo^.LabelTable);
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Dispose(LabelInfo);
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inherited Destroy;
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End;
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constructor TAsmScheduler.Create(_AsmL: TAsmList);
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begin
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inherited create(_asml,nil,nil,nil);
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end;
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procedure TAsmScheduler.SchedulerPass1;
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var
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p : tai;
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begin
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p:=BlockStart;
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while p<>BlockEnd Do
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begin
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if SchedulerPass1Cpu(p) then
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continue;
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p:=tai(p.next);
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end;
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end;
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procedure TAsmScheduler.Optimize;
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Var
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HP: tai;
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Begin
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BlockStart := tai(AsmL.First);
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While Assigned(BlockStart) Do
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Begin
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{ Peephole optimizations }
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SchedulerPass1;
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{ continue where we left off, BlockEnd is either the start of an }
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{ assembler block or nil}
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BlockStart:=BlockEnd;
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While Assigned(BlockStart) And
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(BlockStart.typ = ait_Marker) And
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(tai_Marker(BlockStart).Kind = mark_AsmBlockStart) Do
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Begin
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{ we stopped at an assembler block, so skip it }
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While GetNextInstruction(BlockStart, BlockStart) And
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((BlockStart.Typ <> Ait_Marker) Or
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(tai_Marker(Blockstart).Kind <> mark_AsmBlockEnd)) Do;
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{ blockstart now contains a tai_marker(mark_AsmBlockEnd) }
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If not(GetNextInstruction(BlockStart, HP) And
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((HP.typ <> ait_Marker) Or
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(Tai_Marker(HP).Kind <> mark_AsmBlockStart))) Then
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{ skip the next assembler block }
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blockStart := hp;
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End
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End;
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End;
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procedure Optimize(AsmL:TAsmList);
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var
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p : TAsmOptimizer;
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begin
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p:=casmoptimizer.Create(AsmL);
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p.Optimize;
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{$ifdef DEBUG_INSTRUCTIONREGISTERDEPENDENCIES}
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p.Debug_InsertInstrRegisterDependencyInfo;
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{$endif DEBUG_INSTRUCTIONREGISTERDEPENDENCIES}
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p.free
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end;
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procedure PreRegallocSchedule(AsmL:TAsmList);
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var
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p : TAsmScheduler;
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begin
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p:=cpreregallocscheduler.Create(AsmL);
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p.Optimize;
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p.free
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end;
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end.
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