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* better handling of exit(func_result) (no release of register that
holds the function result added) * several other small improvements for reg allocation fixes
This commit is contained in:
Jonas Maebe
parent
d6bcb83f95
commit
b15a98cfa4
@ -1,6 +1,7 @@
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{
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$Id$
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Copyright (c) 1998-2000 by Jonas Maebe
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Copyright (c) 1998-2000 by Jonas Maebe, member of the Freepascal
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development team
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This unit contains the data flow analyzer and several helper procedures
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and functions.
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@ -73,6 +74,9 @@ Function GetNextInstruction(Current: Pai; Var Next: Pai): Boolean;
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Function GetLastInstruction(Current: Pai; Var Last: Pai): Boolean;
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Procedure SkipHead(var P: Pai);
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Procedure RemoveLastDeallocForFuncRes(asmL: PAasmOutput; p: pai);
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Function regLoadedWithNewValue(reg: tregister; canDependOnPrevValue: boolean;
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hp: pai): boolean;
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Procedure UpdateUsedRegs(Var UsedRegs: TRegSet; p: Pai);
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Function RegsEquivalent(OldReg, NewReg: TRegister; Var RegInfo: TRegInfo; OpAct: TopAction): Boolean;
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Function InstructionsEquivalent(p1, p2: Pai; Var RegInfo: TRegInfo): Boolean;
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@ -218,7 +222,7 @@ Var
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Implementation
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Uses
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globals, systems, strings, verbose, hcodegen;
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globals, systems, strings, verbose, hcodegen, symconst;
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Type
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TRefCompare = function(const r1, r2: TReference): Boolean;
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@ -304,15 +308,14 @@ End;
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Function FindLoHiLabels(Var LowLabel, HighLabel, LabelDif: Longint; BlockStart: Pai): Pai;
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{Walks through the paasmlist to find the lowest and highest label number}
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Var LabelFound: Boolean;
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P: Pai;
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P, lastP: Pai;
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Begin
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LabelFound := False;
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LowLabel := MaxLongint;
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HighLabel := 0;
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P := BlockStart;
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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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lastP := p;
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While Assigned(P) 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)
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@ -324,19 +327,23 @@ Begin
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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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lastP := p;
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GetNextInstruction(p, p);
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End;
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FindLoHiLabels := p;
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if (lastP^.typ = ait_marker) and
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(pai_marker(lastP)^.kind = asmBlockStart) then
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FindLoHiLabels := lastP
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else FindLoHiLabels := nil;
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If LabelFound
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Then LabelDif := HighLabel+1-LowLabel
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Else LabelDif := 0;
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End;
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Function FindRegAlloc(Reg: TRegister; StartPai: Pai): Boolean;
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{Returns true if a ait_alloc object for Reg is found in the block of Pai's
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starting with StartPai and ending with the next "real" instruction}
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Function FindRegAlloc(Reg: TRegister; StartPai: Pai; alloc: boolean): Boolean;
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{ Returns true if a ait_alloc object for Reg is found in the block of Pai's }
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{ starting with StartPai and ending with the next "real" instruction }
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Begin
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FindRegAlloc:=False;
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FindRegAlloc := false;
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Repeat
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While Assigned(StartPai) And
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((StartPai^.typ in (SkipInstr - [ait_regAlloc])) Or
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@ -344,29 +351,106 @@ Begin
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Not(Pai_Label(StartPai)^.l^.Is_Used))) Do
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StartPai := Pai(StartPai^.Next);
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If Assigned(StartPai) And
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(StartPai^.typ = ait_regAlloc) and (PairegAlloc(StartPai)^.allocation) Then
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(StartPai^.typ = ait_regAlloc) and (PairegAlloc(StartPai)^.allocation = alloc) Then
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Begin
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if PairegAlloc(StartPai)^.Reg = Reg then
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begin
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FindRegAlloc:=true;
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exit;
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break;
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end;
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StartPai := Pai(StartPai^.Next);
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End
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else
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exit;
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break;
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Until false;
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End;
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Procedure RemoveLastDeallocForFuncRes(asmL: PAasmOutput; p: pai);
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Procedure DoRemoveLastDeallocForFuncRes(asmL: PAasmOutput; reg: TRegister);
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var hp, hp2: pai;
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begin
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hp := nil;
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hp2 := p;
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repeat
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hp2 := pai(hp2^.previous);
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if assigned(hp2) and
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(hp2^.typ = ait_regalloc) and
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not(pairegalloc(hp2)^.allocation) and
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(pairegalloc(hp2)^.reg = reg) then
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begin
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asml^.remove(hp2);
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dispose(hp2,done);
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break;
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end;
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until not(assigned(hp2)) or
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regInInstruction(reg,hp2);
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end;
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begin
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if assigned(procinfo^.returntype.def) then
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case procinfo^.returntype.def^.deftype of
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arraydef,recorddef,pointerdef,
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stringdef,enumdef,procdef,objectdef,errordef,
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filedef,setdef,procvardef,
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classrefdef,forwarddef:
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DoRemoveLastDeallocForFuncRes(asmL,R_EAX);
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orddef:
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if procinfo^.returntype.def^.size <> 0 then
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begin
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DoRemoveLastDeallocForFuncRes(asmL,R_EAX);
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{ for int64/qword }
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if procinfo^.returntype.def^.size = 8 then
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DoRemoveLastDeallocForFuncRes(asmL,R_EDX);
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end;
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end;
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end;
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procedure getFuncResRegs(var regs: TRegSet);
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begin
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regs := [];
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if assigned(procinfo^.returntype.def) then
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case procinfo^.returntype.def^.deftype of
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arraydef,recorddef,pointerdef,
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stringdef,enumdef,procdef,objectdef,errordef,
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filedef,setdef,procvardef,
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classrefdef,forwarddef:
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regs := [R_EAX];
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orddef:
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if procinfo^.returntype.def^.size <> 0 then
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begin
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regs := [R_EAX];
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{ for int64/qword }
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if procinfo^.returntype.def^.size = 8 then
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regs := regs + [R_EDX];
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end;
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end
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end;
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Procedure AddRegDeallocFor(asmL: paasmOutput; reg: TRegister; p: pai);
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var hp1: pai;
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funcResRegs: TRegset;
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funcResReg: boolean;
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begin
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getFuncResRegs(funcResRegs);
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funcResReg := reg in funcResRegs;
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hp1 := p;
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While GetLastInstruction(p, p) And
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Not(RegInInstruction(reg, p)) Do
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while not(funcResReg and
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(p^.typ = ait_instruction) and
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(paicpu(p)^.opcode = A_JMP) and
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(pasmlabel(paicpu(p)^.oper[0].sym) = aktexit2label)) and
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getLastInstruction(p, p) And
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not(regInInstruction(reg, p)) Do
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hp1 := p;
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p := New(PaiRegAlloc, DeAlloc(reg));
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InsertLLItem(AsmL, hp1^.previous, hp1, p);
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{ don't insert a dealloc for registers which contain the function result }
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{ if they are followed by a jump to the exit label (for exit(...)) }
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if not((hp1^.typ = ait_instruction) and
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(paicpu(hp1)^.opcode = A_JMP) and
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(pasmlabel(paicpu(hp1)^.oper[0].sym) = aktexit2label)) then
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begin
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p := new(paiRegAlloc, deAlloc(reg));
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insertLLItem(AsmL, hp1^.previous, hp1, p);
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end;
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end;
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Procedure BuildLabelTableAndFixRegAlloc(asmL: PAasmOutput; Var LabelTable: PLabelTable; LowLabel: Longint;
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@ -375,7 +459,7 @@ Procedure BuildLabelTableAndFixRegAlloc(asmL: PAasmOutput; Var LabelTable: PLabe
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Also fixes some RegDeallocs like "# %eax released; push (%eax)"}
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Var p, hp1, hp2, lastP: Pai;
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regCounter: TRegister;
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UsedRegs: TRegSet;
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UsedRegs, funcResRegs: TRegSet;
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Begin
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UsedRegs := [];
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If (LabelDif <> 0) Then
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@ -403,39 +487,42 @@ Begin
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ait_regAlloc:
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{ ESI and EDI are (de)allocated manually, don't mess with them }
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if not(paiRegAlloc(p)^.Reg in [R_EDI,R_ESI]) then
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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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addRegDeallocFor(asmL, paiRegAlloc(p)^.reg, p);
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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(AsmL, 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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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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addRegDeallocFor(asmL, paiRegAlloc(p)^.reg, p);
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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),true)) 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(AsmL, 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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repeat
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lastP := p;
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P := Pai(P^.Next);
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until not(Assigned(p) And
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(p^.typ in (SkipInstr - [ait_regalloc])));
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until not(Assigned(p)) or
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not(p^.typ in (SkipInstr - [ait_regalloc]));
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End;
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{ don't add deallocation for function result variable }
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getFuncResRegs(funcResRegs);
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usedRegs := usedRegs - funcResRegs;
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for regCounter := R_EAX to R_EDI do
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if regCounter in usedRegs then
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addRegDeallocFor(asmL,regCounter,lastP);
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@ -783,8 +870,8 @@ End;
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{********************* GetNext and GetLastInstruction *********************}
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Function GetNextInstruction(Current: Pai; Var Next: Pai): Boolean;
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{skips ait_regalloc, ait_regdealloc and ait_stab* objects and puts the
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next pai object in Next. Returns false if there isn't any}
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{ skips ait_regalloc, ait_regdealloc and ait_stab* objects and puts the }
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{ next pai object in Next. Returns false if there isn't any }
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Begin
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Repeat
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If (Current^.typ = ait_marker) And
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@ -817,7 +904,10 @@ Begin
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Not((Current^.typ In SkipInstr) or
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((Current^.typ = ait_label) And
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Not(Pai_Label(Current)^.l^.is_used)))
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Then GetNextInstruction := True
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Then
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GetNextInstruction :=
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not((current^.typ = ait_marker) and
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(pai_marker(current)^.kind = asmBlockStart))
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Else
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Begin
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GetNextInstruction := False;
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@ -882,18 +972,40 @@ Begin
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{a marker of the NoPropInfoStart can't be the first instruction of a
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paasmoutput list}
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GetNextInstruction(Pai(P^.Previous),P);
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If (P^.Typ = Ait_Marker) And
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{ If (P^.Typ = Ait_Marker) And
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(Pai_Marker(P)^.Kind = AsmBlockStart) Then
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Begin
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P := Pai(P^.Next);
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While (P^.typ <> Ait_Marker) Or
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(Pai_Marker(P)^.Kind <> AsmBlockEnd) Do
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P := Pai(P^.Next)
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End;
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End;}
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Until P = OldP
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End;
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{******************* The Data Flow Analyzer functions ********************}
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function regLoadedWithNewValue(reg: tregister; canDependOnPrevValue: boolean;
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hp: pai): boolean;
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{ assumes reg is a 32bit register }
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var p: paicpu;
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begin
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p := paicpu(hp);
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regLoadedWithNewValue :=
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assigned(hp) and
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(hp^.typ = ait_instruction) and
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(((p^.opcode = A_MOV) or
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(p^.opcode = A_MOVZX) or
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(p^.opcode = A_MOVSX) or
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(p^.opcode = A_LEA)) and
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(p^.oper[1].typ = top_reg) and
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(Reg32(p^.oper[1].reg) = reg) and
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(canDependOnPrevValue or
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(p^.oper[0].typ <> top_ref) or
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not regInRef(reg,p^.oper[0].ref^)) or
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((p^.opcode = A_POP) and
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(Reg32(p^.oper[0].reg) = reg)));
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end;
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Procedure UpdateUsedRegs(Var UsedRegs: TRegSet; p: Pai);
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{updates UsedRegs with the RegAlloc Information coming after P}
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Begin
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@ -2019,7 +2131,12 @@ End.
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{
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$Log$
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Revision 1.78 2000-01-13 13:07:06 jonas
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Revision 1.79 2000-01-22 16:08:06 jonas
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* better handling of exit(func_result) (no release of register that
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holds the function result added)
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* several other small improvements for reg allocation fixes
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Revision 1.78 2000/01/13 13:07:06 jonas
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* released -dalignreg
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* some small fixes to -dnewOptimizations helper procedures
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