{
Copyright (c) 1998-2004 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;
{$i fpcdefs.inc}
Interface
Uses
aasmbase,aasmtai,aasmdata,aasmcpu,
aoptobj;
Type
TAsmOptimizer = class(TAoptObj)
{ _AsmL is the PAasmOutpout list that has to be optimized }
Constructor create(_AsmL: TAsmList); virtual;
{ call the necessary optimizer procedures }
Procedure Optimize;
Destructor destroy;override;
private
procedure FindLoHiLabels;
Procedure BuildLabelTableAndFixRegAlloc;
procedure clear;
procedure pass_1;
End;
var
casmoptimizer : class of tasmoptimizer;
procedure Optimize(AsmL:TAsmList);
Implementation
uses
globtype, globals,
verbose,
aoptda,aoptcpu,aoptcpud;
Constructor TAsmOptimizer.create(_AsmL: TAsmList);
Begin
inherited create(_asml,nil,nil,nil);
{setup labeltable, always necessary}
New(LabelInfo);
End;
procedure TAsmOptimizer.FindLoHiLabels;
{ 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, prev: tai;
Begin
LabelInfo^.LowLabel := High(AWord);
LabelInfo^.HighLabel := 0;
LabelInfo^.LabelDif := 0;
LabelInfo^.LabelTable:=nil;
LabelFound := False;
P := BlockStart;
prev := p;
With LabelInfo^ Do
Begin
While Assigned(P) And
((P.typ <> Ait_Marker) Or
(tai_Marker(P).Kind <> mark_AsmBlockStart)) Do
Begin
If (p.typ = ait_label) and
(tai_Label(p).labsym.labeltype=alt_jump) and
(tai_Label(p).labsym.is_used) Then
Begin
LabelFound := True;
If (tai_Label(p).labsym.labelnr < LowLabel) Then
LowLabel := tai_Label(p).labsym.labelnr;
If (tai_Label(p).labsym.labelnr > HighLabel) Then
HighLabel := tai_Label(p).labsym.labelnr
End;
prev := p;
GetNextInstruction(p, p)
End;
blockend:=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 TAsmList. }
{ Also fixes some RegDeallocs like "# %eax released; push (%eax)" }
Var p, hp1, hp2: tai;
UsedRegs: TRegSet;
LabelIdx : longint;
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:
begin
If tai_label(p).labsym.is_used and
(tai_Label(p).labsym.labeltype=alt_jump) then
begin
LabelIdx:=tai_label(p).labsym.labelnr-LowLabel;
if LabelIdx>LabelDif then
internalerror(200604202);
LabelTable^[LabelIdx].PaiObj := p;
end;
end;
ait_regAlloc:
begin
{!!!!!!!!!
if tai_regalloc(p).ratype=ra_alloc then
Begin
If Not(tai_regalloc(p).Reg in UsedRegs) Then
UsedRegs := UsedRegs + [tai_regalloc(p).Reg]
Else
Begin
hp1 := p;
hp2 := nil;
While GetLastInstruction(hp1, hp1) And
Not(RegInInstruction(tai_regalloc(p).Reg, hp1)) Do
hp2:=hp1;
If hp2<>nil Then
Begin
hp1:=tai_regalloc.DeAlloc(tai_regalloc(p).Reg,hp2);
InsertLLItem(tai(hp2.previous), hp2, hp1);
End;
End;
End
else
Begin
UsedRegs := UsedRegs - [tai_regalloc(p).Reg];
hp1 := p;
hp2 := nil;
While Not(FindRegAlloc(tai_regalloc(p).Reg, tai(hp1.Next))) And
GetNextInstruction(hp1, hp1) And
RegInInstruction(tai_regalloc(p).Reg, hp1) Do
hp2 := hp1;
If hp2 <> nil Then
Begin
hp1 := tai(p.previous);
AsmL.Remove(p);
InsertLLItem(hp2, tai(hp2.Next), p);
p := hp1;
End
End
};
End
End;
P := tai(p.Next);
While Assigned(p) and
(p <> blockend) and
(p.typ in (SkipInstr - [ait_regalloc])) Do
P := tai(P.Next)
End;
End
End;
procedure tasmoptimizer.clear;
begin
if assigned(LabelInfo^.labeltable) then
begin
freemem(LabelInfo^.labeltable);
LabelInfo^.labeltable := nil;
end;
LabelInfo^.labeldif:=0;
LabelInfo^.lowlabel:=high(AWord);
LabelInfo^.highlabel:=0;
end;
procedure tasmoptimizer.pass_1;
begin
findlohilabels;
BuildLabelTableAndFixRegAlloc;
end;
Procedure TAsmOptimizer.Optimize;
Var
HP: tai;
pass: longint;
Begin
pass:=0;
BlockStart := tai(AsmL.First);
pass_1;
While Assigned(BlockStart) Do
Begin
if pass = 0 then
PrePeepHoleOpts;
{ Peephole optimizations }
PeepHoleOptPass1;
{ Only perform them twice in the first pass }
if pass = 0 then
PeepHoleOptPass1;
If (cs_opt_asmcse in current_settings.optimizerswitches) Then
Begin
// DFA:=TAOptDFACpu.Create(AsmL,BlockStart,BlockEnd,LabelInfo);
{ data flow analyzer }
// DFA.DoDFA;
{ common subexpression elimination }
{ CSE;}
End;
{ more peephole optimizations }
PeepHoleOptPass2;
{ if pass = last_pass then }
PostPeepHoleOpts;
{ free memory }
clear;
{ 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
(tai_Marker(BlockStart).Kind = mark_AsmBlockStart) Do
Begin
{ we stopped at an assembler block, so skip it }
While GetNextInstruction(BlockStart, BlockStart) And
((BlockStart.Typ <> Ait_Marker) Or
(tai_Marker(Blockstart).Kind <> mark_AsmBlockEnd)) Do;
{ blockstart now contains a tai_marker(mark_AsmBlockEnd) }
If GetNextInstruction(BlockStart, HP) And
((HP.typ <> ait_Marker) Or
(Tai_Marker(HP).Kind <> mark_AsmBlockStart)) Then
{ There is no assembler block anymore after the current one, so }
{ optimize the next block of "normal" instructions }
pass_1
{ Otherwise, skip the next assembler block }
else
blockStart := hp;
End
End;
End;
Destructor TAsmOptimizer.Destroy;
Begin
Dispose(LabelInfo)
End;
procedure Optimize(AsmL:TAsmList);
var
p : TAsmOptimizer;
begin
p:=casmoptimizer.Create(AsmL);
p.Optimize;
p.free
end;
end.
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