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Patch by Gareth Moreton.

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* TAOptObj.CollapseZeroDistJump: Change hp1 to local variable,
     initialized as p.next, to avoid problems of dangling pointers
     revealed by use of "-CriotR -O2" compilation arguments.

git-svn-id: trunk@43554 -
This commit is contained in:
pierre 2019-11-22 09:10:32 +00:00
parent 98226d33b7
commit 17c422c3f2
1 changed files with 12 additions and 7 deletions
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19
compiler/aoptobj.pas
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@ -394,7 +394,7 @@ Unit AoptObj;
procedure StripLabelFast(hp: tai); {$ifdef USEINLINE}inline;{$endif USEINLINE}
{ Checks and removes "jmp @@lbl; @lbl". Returns True if the jump was removed }
function CollapseZeroDistJump(var p: tai; hp1: tai; ThisLabel: TAsmLabel): Boolean;
function CollapseZeroDistJump(var p: tai; ThisLabel: TAsmLabel): Boolean;
{ If a group of labels are clustered, change the jump to point to the last one that is still referenced }
function CollapseLabelCluster(jump: tai; var lbltai: tai): TAsmLabel;
@ -2006,7 +2006,7 @@ Unit AoptObj;
end;
{$endif arm or aarch64}
end
else if Assigned(hp2) and CollapseZeroDistJump(hp1, hp2, NCJLabel) then
else if CollapseZeroDistJump(hp1, NCJLabel) then
begin
{ Attempt another iteration in case more jumps follow }
Continue;
@ -2101,11 +2101,15 @@ Unit AoptObj;
end;
{$endif JVM}
function TAOptObj.CollapseZeroDistJump(var p: tai; hp1: tai; ThisLabel: TAsmLabel): Boolean;
function TAOptObj.CollapseZeroDistJump(var p: tai; ThisLabel: TAsmLabel): Boolean;
var
tmp: tai;
tmp, hp1: tai;
begin
Result := False;
hp1 := tai(p.Next);
tmp := hp1; { Might be an align before the label, so keep a note of it }
if (hp1 = BlockEnd) then
Exit;
{ remove jumps to labels coming right after them }
if FindLabel(ThisLabel, hp1) and
@ -2114,7 +2118,6 @@ Unit AoptObj;
begin
ThisLabel.decrefs;
tmp := tai(p.Next); { Might be an align before the label }
{$ifdef cpudelayslot}
RemoveDelaySlot(p);
{$endif cpudelayslot}
@ -2170,7 +2173,7 @@ Unit AoptObj;
in order to aid optimisation later }
ThisLabel := CollapseLabelCluster(p, hp2);
if CollapseZeroDistJump(p, hp1, ThisLabel) then
if CollapseZeroDistJump(p, ThisLabel) then
begin
stoploop := False;
Result := True;
@ -2236,9 +2239,11 @@ Unit AoptObj;
(taicpu(p1).is_jmp) then
begin
p2 := tai(p1.Next);
if p2 = BlockEnd then
Exit;
{ Collapse any zero distance jumps we stumble across }
while (p1<>StartPoint) and CollapseZeroDistJump(p1, p2, TAsmLabel(JumpTargetOp(taicpu(p1))^.ref^.symbol)) do
while (p1<>StartPoint) and CollapseZeroDistJump(p1, TAsmLabel(JumpTargetOp(taicpu(p1))^.ref^.symbol)) do
begin
{ Note: Cannot remove the first instruction }
if (p1.typ = ait_label) then