mirror of
https://gitlab.com/freepascal.org/fpc/source.git
synced 2025-07-23 02:36:16 +02:00
56524f33df
+ dataflow analyzer finished
+ start of CSE units
+ aoptbase which contains a base object for all optimizer objects
* some constants and type definitions moved around to avoid circular
dependencies
* moved some methods from base objects to specialized objects because
they're not used anywhere else
249 lines
8.1 KiB
ObjectPascal
249 lines
8.1 KiB
ObjectPascal
{
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$Id$
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Copyright (c) 1999 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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Interface
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Uses Aasm, cobjects, aoptobj, aoptcpud, aoptcpub {aoptcs, aoptpeep} ;
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Type
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TAsmOptimizer = Object(TAoptObj)
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{ _AsmL is the PAasmOutpout list that has to be optimized }
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Constructor Init(_AsmL: PAasmOutput);
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{ call the necessary optimizer procedures }
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Procedure Optimize;
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Destructor Done;
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private
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Function FindLoHiLabels: Pai;
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Procedure BuildLabelTableAndFixRegAlloc;
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End;
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Implementation
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uses cpuinfo, globtype, globals, tainst;
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Constructor TAsmOptimizer.Init(_AsmL: PAasmOutput);
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Begin
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AsmL := _AsmL;
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{setup labeltable, always necessary}
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New(LabelInfo);
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LabelInfo^.LowLabel := High(AWord);
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LabelInfo^.HighLabel := 0;
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LabelInfo^.LabelDif := 0;
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End;
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Function TAsmOptimizer.FindLoHiLabels: Pai;
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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: Pai;
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Begin
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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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(Pai_Marker(P)^.Kind <> AsmBlockStart)) Do
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Begin
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If (Pai(p)^.typ = ait_label) Then
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If (Pai_Label(p)^.l^.is_used) Then
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Begin
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LabelFound := True;
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If (Pai_Label(p)^.l^.labelnr < LowLabel) Then
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LowLabel := Pai_Label(p)^.l^.labelnr;
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If (Pai_Label(p)^.l^.labelnr > HighLabel) Then
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HighLabel := Pai_Label(p)^.l^.labelnr
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End;
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GetNextInstruction(p, p)
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End;
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FindLoHiLabels := 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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{ Builds a table with the locations of the labels in the paasmoutput. }
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{ Also fixes some RegDeallocs like "# %eax released; push (%eax)" }
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Var p, hp1, hp2: Pai;
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UsedRegs: TRegSet;
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Begin
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UsedRegs := [];
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With LabelInfo^ Do
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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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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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If Pai_Label(p)^.l^.is_used Then
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LabelTable^[Pai_Label(p)^.l^.labelnr-LowLabel].PaiObj := p;
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ait_regAlloc:
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begin
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if PairegAlloc(p)^.Allocation then
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Begin
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If Not(PaiRegAlloc(p)^.Reg in UsedRegs) Then
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UsedRegs := UsedRegs + [PaiRegAlloc(p)^.Reg]
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Else
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Begin
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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(PaiRegAlloc(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 := New(PaiRegAlloc, DeAlloc(PaiRegAlloc(p)^.Reg));
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InsertLLItem(Pai(hp2^.previous), hp2, hp1);
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End;
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End;
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End
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else
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Begin
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UsedRegs := UsedRegs - [PaiRegAlloc(p)^.Reg];
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hp1 := p;
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hp2 := nil;
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While Not(FindRegAlloc(PaiRegAlloc(p)^.Reg, Pai(hp1^.Next))) And
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GetNextInstruction(hp1, hp1) And
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RegInInstruction(PaiRegAlloc(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 := Pai(p^.previous);
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AsmL^.Remove(p);
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InsertLLItem(hp2, Pai(hp2^.Next), p);
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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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End;
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P := Pai(p^.Next);
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While Assigned(p) And
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(p^.typ in (SkipInstr - [ait_regalloc])) Do
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P := Pai(P^.Next)
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End
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End;
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Procedure TAsmOptimizer.Optimize;
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Var HP: Pai;
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DFA: PAOptDFACpu;
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Begin
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BlockStart := Pai(AsmL^.First);
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While Assigned(BlockStart) Do
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Begin
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{ Initialize BlockEnd and the LabelInfo (low and high label) }
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BlockEnd := FindLoHiLabels;
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{ initialize the LabelInfo (labeltable) and fix the regalloc info }
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BuildLabelTableAndFixRegAlloc;
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{ peephole optimizations, twice because you can't do them all in one }
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{ pass }
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{ PeepHoleOptPass1;
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PeepHoleOptPass1;}
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If (cs_slowoptimize in aktglobalswitches) Then
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Begin
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New(DFA,Init(AsmL,BlockStart,BlockEnd,LabelInfo));
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{ data flow analyzer }
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DFA^.DoDFA;
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{ common subexpression elimination }
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{ CSE;}
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End;
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{ more peephole optimizations }
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{ PeepHoleOptPass2;}
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{dispose labeltabel}
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If Assigned(LabelInfo^.LabelTable) Then
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Begin
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Dispose(LabelInfo^.LabelTable);
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LabelInfo := Nil
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End;
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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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(Pai_Marker(BlockStart)^.Kind = 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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(Pai_Marker(Blockstart)^.Kind <> AsmBlockEnd)) Do;
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{ blockstart now contains a pai_marker(asmblockend) }
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If Not(GetNextInstruction(BlockStart, HP) And
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((HP^.typ <> ait_Marker) Or
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(Pai_Marker(HP)^.Kind <> AsmBlockStart)
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)
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) Then
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{skip the next assembler block }
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BlockStart := HP;
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{ otherwise there is no assembler block anymore after the current }
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{ one, so optimize the next block of "normal" instructions }
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End
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End;
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End;
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Destructor TAsmOptimizer.Done;
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Begin
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Dispose(LabelInfo)
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End;
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End.
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{Virtual methods, most have to be overridden by processor dependent methods}
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{
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$Log$
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Revision 1.3 1999-08-18 14:32:20 jonas
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+ compilable!
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+ dataflow analyzer finished
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+ start of CSE units
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+ aoptbase which contains a base object for all optimizer objects
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* some constants and type definitions moved around to avoid circular
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dependencies
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* moved some methods from base objects to specialized objects because
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they're not used anywhere else
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Revision 1.2 1999/08/09 14:07:22 jonas
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commit.msg
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Revision 1.1 1999/08/08 13:24:50 jonas
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+ added copyright header/GNU license info
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* made the assembler optimizer almost completely OOP
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* some code style clean up and extra comments
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* moved from the new/aopt to the /new and /new/i386 dirs
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} |