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{
Copyright (c) 1998-2002 by Jonas Maebe, member of the Free Pascal
Development Team
This unit contains the base of all optimizer related objects
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 aoptbase;
{$i fpcdefs.inc}
interface
uses
aasmbase,aasmcpu,aasmtai,aasmdata,
cpubase,
cgbase,
cgutils;
Type
{ the number of tai objects processed by an optimizer object since the last
time a register was modified }
{ size at each dimension depends on the registers of this type }
TInstrSinceLastMod = Array[tregistertype] of pbyte;
{ the TAopBase object implements the basic methods that most other }
{ assembler optimizer objects require }
Type
TAoptBase = class
{ processor independent methods }
constructor create; virtual;
destructor destroy;override;
{ returns true if register Reg is used by instruction p1 }
Function RegInInstruction(Reg: TRegister; p1: tai): Boolean;virtual;
{ returns true if register Reg occurs in operand op }
Function RegInOp(Reg: TRegister; const op: toper): Boolean;
{ returns true if register Reg is used in the reference Ref }
Function RegInRef(Reg: TRegister; Const Ref: TReference): Boolean;
function RegModifiedByInstruction(Reg: TRegister; p1: tai): boolean;virtual;
{ returns true if the references are completely equal }
{Function RefsEqual(Const R1, R2: TReference): Boolean;}
{ gets the next tai object after current that contains info relevant }
{ to the optimizer in p1. If there is none, it returns false and }
{ sets p1 to nil }
Function GetNextInstruction(Current: tai; Var Next: tai): Boolean;
{ gets the previous tai object after current that contains info }
{ relevant to the optimizer in last. If there is none, it retuns }
{ false and sets last to nil }
Function GetLastInstruction(Current: tai; Var Last: tai): Boolean;
{ processor dependent methods }
{ returns the maximum width component of Reg. Only has to be }
{ overridden for the 80x86 (afaik) }
Function RegMaxSize(Reg: TRegister): TRegister; Virtual;
{ returns true if Reg1 and Reg2 are of the samae width. Only has to }
{ overridden for the 80x86 (afaik) }
Function RegsSameSize(Reg1, Reg2: TRegister): Boolean; Virtual;
{ returns whether P is a load instruction (load contents from a }
{ memory location or (register) variable into a register) }
Function IsLoadMemReg(p: tai): Boolean; Virtual; Abstract;
{ returns whether P is a load constant instruction (load a constant }
{ into a register) }
Function IsLoadConstReg(p: tai): Boolean; Virtual; Abstract;
{ returns whether P is a store instruction (store contents from a
register to a memory location or to a (register) variable) }
Function IsStoreRegMem(p: tai): Boolean; Virtual; Abstract;
{ create a paicpu Object that loads the contents of reg1 into reg2 }
Function a_load_reg_reg(reg1, reg2: TRegister): taicpu; Virtual; Abstract;
end;
function labelCanBeSkipped(p: tai_label): boolean;
implementation
uses
globtype,globals,aoptcpub;
constructor taoptbase.create;
begin
inherited create;
end;
destructor taoptbase.destroy;
begin
inherited destroy;
end;
Function TAOptBase.RegInInstruction(Reg: TRegister; p1: tai): Boolean;
Var Count: AWord;
TmpResult: Boolean;
Begin
TmpResult := False;
Count := 0;
If (p1.typ = ait_instruction) and assigned(TInstr(p1).oper[0]) Then
Repeat
TmpResult := RegInOp(Reg, TInstr(p1).oper[Count]^);
Inc(Count)
Until (TInstr(p1).oper[Count]=nil) or (Count = MaxOps) or TmpResult;
RegInInstruction := TmpResult
End;
Function TAOptBase.RegInOp(Reg: TRegister; const op: toper): Boolean;
Begin
Case op.typ Of
Top_Reg: RegInOp := Reg = op.reg;
Top_Ref: RegInOp := RegInRef(Reg, op.ref^);
{$ifdef arm}
Top_Shifterop: RegInOp := op.shifterop^.rs = Reg;
Top_RegSet: RegInOp := getsupreg(Reg) in op.regset^;
{$endif arm}
Else RegInOp := False
End
End;
Function TAOptBase.RegInRef(Reg: TRegister; Const Ref: TReference): Boolean;
Begin
Reg := RegMaxSize(Reg);
RegInRef := (Ref.Base = Reg)
{$ifdef cpurefshaveindexreg}
Or (Ref.Index = Reg)
{$endif cpurefshaveindexreg}
End;
Function TAOptBase.RegModifiedByInstruction(Reg: TRegister; p1: tai): Boolean;
Begin
Result:=true;
End;
function labelCanBeSkipped(p: tai_label): boolean;
begin
labelCanBeSkipped := not(p.labsym.is_used) or (p.labsym.labeltype<>alt_jump);
end;
Function TAOptBase.GetNextInstruction(Current: tai; Var Next: tai): Boolean;
Begin
Repeat
Current := tai(Current.Next);
While Assigned(Current) And
((Current.typ In SkipInstr) or
{$ifdef SPARC}
((Current.typ=ait_instruction) and
(taicpu(Current).opcode=A_NOP)
) or
{$endif SPARC}
((Current.typ = ait_label) And
labelCanBeSkipped(Tai_Label(Current)))) Do
Current := tai(Current.Next);
If Assigned(Current) And
(Current.typ = ait_Marker) And
(Tai_Marker(Current).Kind = mark_NoPropInfoStart) Then
Begin
While Assigned(Current) And
((Current.typ <> ait_Marker) Or
(Tai_Marker(Current).Kind <> mark_NoPropInfoEnd)) Do
Current := Tai(Current.Next);
End;
Until Not(Assigned(Current)) Or
(Current.typ <> ait_Marker) Or
(Tai_Marker(Current).Kind <> mark_NoPropInfoEnd);
Next := Current;
If Assigned(Current) And
Not((Current.typ In SkipInstr) or
((Current.typ = ait_label) And
labelCanBeSkipped(Tai_Label(Current))))
Then GetNextInstruction := True
Else
Begin
Next := Nil;
GetNextInstruction := False;
End;
End;
Function TAOptBase.GetLastInstruction(Current: tai; Var Last: tai): Boolean;
Begin
Repeat
Current := Tai(Current.previous);
While Assigned(Current) And
(((Current.typ = ait_Marker) And
Not(Tai_Marker(Current).Kind in [mark_AsmBlockEnd{,mark_NoPropInfoEnd}])) or
(Current.typ In SkipInstr) or
((Current.typ = ait_label) And
labelCanBeSkipped(Tai_Label(Current)))) Do
Current := Tai(Current.previous);
{ If Assigned(Current) And
(Current.typ = ait_Marker) And
(Tai_Marker(Current).Kind = mark_NoPropInfoEnd) Then
Begin
While Assigned(Current) And
((Current.typ <> ait_Marker) Or
(Tai_Marker(Current).Kind <> mark_NoPropInfoStart)) Do
Current := Tai(Current.previous);
End; }
Until Not(Assigned(Current)) Or
(Current.typ <> ait_Marker) Or
not(tai_Marker(current).Kind in [mark_NoPropInfoStart,mark_NoPropInfoEnd]);
If Not(Assigned(Current)) or
(Current.typ In SkipInstr) or
((Current.typ = ait_label) And
labelCanBeSkipped(Tai_Label(Current))) or
((Current.typ = ait_Marker) And
(Tai_Marker(Current).Kind = mark_AsmBlockEnd))
Then
Begin
Last := Nil;
GetLastInstruction := False
End
Else
Begin
Last := Current;
GetLastInstruction := True;
End;
End;
{ ******************* Processor dependent stuff *************************** }
Function TAOptBase.RegMaxSize(Reg: TRegister): TRegister;
Begin
RegMaxSize := Reg
End;
Function TAOptBase.RegsSameSize(Reg1, Reg2: TRegister): Boolean;
Begin
RegsSameSize := True
End;
end.
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