{
$Id: aopt.pas,v 1.5 2002/07/01 18:46:21 peter Exp $
Copyright (c) 1998-2002 by Jonas Maebe, member of the Free Pascal
Development Team
This unit contains the interface routines between the code generator
and the optimizer.
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., 675 Mass Ave, Cambridge, MA 02139, USA.
****************************************************************************
}
Unit aopt;
Interface
Uses Aasmbase,aasmtai,aasmcpu, cobjects, aoptobj, aoptcpud, aoptcpub {aoptcs, aoptpeep} ;
Type
PAsmOptimizer = ^TAsmOptimizer;
TAsmOptimizer = Object(TAoptObj)
{ _AsmL is the PAasmOutpout list that has to be optimized }
Constructor Init(_AsmL: PAasmOutput);
{ call the necessary optimizer procedures }
Procedure Optimize;
Destructor Done;
private
Function FindLoHiLabels: Pai;
Procedure BuildLabelTableAndFixRegAlloc;
End;
procedure Optimize(AsmL:Paasmoutput);
Implementation
uses cpuinfo, globtype, globals;
Constructor TAsmOptimizer.Init(_AsmL: PAasmOutput);
Begin
AsmL := _AsmL;
{setup labeltable, always necessary}
New(LabelInfo);
LabelInfo^.LowLabel := High(AWord);
LabelInfo^.HighLabel := 0;
LabelInfo^.LabelDif := 0;
End;
Function TAsmOptimizer.FindLoHiLabels: Pai;
{ Walks through the paasmlist to find the lowest and highest label number. }
{ Returns the last Pai object of the current block }
Var LabelFound: Boolean;
P: Pai;
Begin
LabelFound := False;
P := BlockStart;
With LabelInfo^ Do
Begin
While Assigned(P) And
((P^.typ <> Ait_Marker) Or
(Pai_Marker(P)^.Kind <> AsmBlockStart)) Do
Begin
If (Pai(p)^.typ = ait_label) Then
If (Pai_Label(p)^.l^.is_used) Then
Begin
LabelFound := True;
If (Pai_Label(p)^.l^.labelnr < LowLabel) Then
LowLabel := Pai_Label(p)^.l^.labelnr;
If (Pai_Label(p)^.l^.labelnr > HighLabel) Then
HighLabel := Pai_Label(p)^.l^.labelnr
End;
GetNextInstruction(p, p)
End;
FindLoHiLabels := p;
If LabelFound
Then LabelDif := HighLabel-LowLabel+1
Else LabelDif := 0
End
End;
Procedure TAsmOptimizer.BuildLabelTableAndFixRegAlloc;
{ Builds a table with the locations of the labels in the paasmoutput. }
{ Also fixes some RegDeallocs like "# %eax released; push (%eax)" }
Var p, hp1, hp2: Pai;
UsedRegs: TRegSet;
Begin
UsedRegs := [];
With LabelInfo^ Do
If (LabelDif <> 0) Then
Begin
GetMem(LabelTable, LabelDif*SizeOf(TLabelTableItem));
FillChar(LabelTable^, LabelDif*SizeOf(TLabelTableItem), 0);
p := BlockStart;
While (P <> BlockEnd) Do
Begin
Case p^.typ Of
ait_Label:
If Pai_Label(p)^.l^.is_used Then
LabelTable^[Pai_Label(p)^.l^.labelnr-LowLabel].PaiObj := p;
ait_regAlloc:
begin
if PairegAlloc(p)^.Allocation then
Begin
If Not(PaiRegAlloc(p)^.Reg in UsedRegs) Then
UsedRegs := UsedRegs + [PaiRegAlloc(p)^.Reg]
Else
Begin
hp1 := p;
hp2 := nil;
While GetLastInstruction(hp1, hp1) And
Not(RegInInstruction(PaiRegAlloc(p)^.Reg, hp1)) Do
hp2 := hp1;
If hp2 <> nil Then
Begin
hp1 := New(PaiRegAlloc, DeAlloc(PaiRegAlloc(p)^.Reg));
InsertLLItem(Pai(hp2^.previous), hp2, hp1);
End;
End;
End
else
Begin
UsedRegs := UsedRegs - [PaiRegAlloc(p)^.Reg];
hp1 := p;
hp2 := nil;
While Not(FindRegAlloc(PaiRegAlloc(p)^.Reg, Pai(hp1^.Next))) And
GetNextInstruction(hp1, hp1) And
RegInInstruction(PaiRegAlloc(p)^.Reg, hp1) Do
hp2 := hp1;
If hp2 <> nil Then
Begin
hp1 := Pai(p^.previous);
AsmL^.Remove(p);
InsertLLItem(hp2, Pai(hp2^.Next), p);
p := hp1;
End
End
End
End
End;
P := Pai(p^.Next);
While Assigned(p) And
(p^.typ in (SkipInstr - [ait_regalloc])) Do
P := Pai(P^.Next)
End
End;
Procedure TAsmOptimizer.Optimize;
Var HP: Pai;
DFA: PAOptDFACpu;
Begin
BlockStart := Pai(AsmL^.First);
While Assigned(BlockStart) Do
Begin
{ Initialize BlockEnd and the LabelInfo (low and high label) }
BlockEnd := FindLoHiLabels;
{ initialize the LabelInfo (labeltable) and fix the regalloc info }
BuildLabelTableAndFixRegAlloc;
{ peephole optimizations, twice because you can't do them all in one }
{ pass }
{ PeepHoleOptPass1;
PeepHoleOptPass1;}
If (cs_slowoptimize in aktglobalswitches) Then
Begin
New(DFA,Init(AsmL,BlockStart,BlockEnd,LabelInfo));
{ data flow analyzer }
DFA^.DoDFA;
{ common subexpression elimination }
{ CSE;}
End;
{ more peephole optimizations }
{ PeepHoleOptPass2;}
{dispose labeltabel}
If Assigned(LabelInfo^.LabelTable) Then
Begin
Dispose(LabelInfo^.LabelTable);
LabelInfo := Nil
End;
{ continue where we left off, BlockEnd is either the start of an }
{ assembler block or nil}
BlockStart := BlockEnd;
While Assigned(BlockStart) And
(BlockStart^.typ = ait_Marker) And
(Pai_Marker(BlockStart)^.Kind = AsmBlockStart) Do
Begin
{ we stopped at an assembler block, so skip it }
While GetNextInstruction(BlockStart, BlockStart) And
((BlockStart^.Typ <> Ait_Marker) Or
(Pai_Marker(Blockstart)^.Kind <> AsmBlockEnd)) Do;
{ blockstart now contains a pai_marker(asmblockend) }
If Not(GetNextInstruction(BlockStart, HP) And
((HP^.typ <> ait_Marker) Or
(Pai_Marker(HP)^.Kind <> AsmBlockStart)
)
) Then
{skip the next assembler block }
BlockStart := HP;
{ otherwise there is no assembler block anymore after the current }
{ one, so optimize the next block of "normal" instructions }
End
End;
End;
Destructor TAsmOptimizer.Done;
Begin
Dispose(LabelInfo)
End;
procedure Optimize(AsmL:Paasmoutput);
var
p : PAsmOptimizer;
begin
new(p,Init(AsmL));
p^.Optimize;
dispose(p,Done);
end;
End.
{Virtual methods, most have to be overridden by processor dependent methods}
{
$Log: aopt.pas,v $
Revision 1.5 2002/07/01 18:46:21 peter
* internal linker
* reorganized aasm layer
Revision 1.4 2002/05/18 13:34:05 peter
* readded missing revisions
Revision 1.3 2002/05/16 19:46:34 carl
+ defines.inc -> fpcdefs.inc to avoid conflicts if compiling by hand
+ try to fix temp allocation (still in ifdef)
+ generic constructor calls
+ start of tassembler / tmodulebase class cleanup
}
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