Ok I reproduced it. (compiled with -gh -gt -O1 => but I am not sure it
matters
Question: Is it some wrong doing of me? or shall i report it as bug?
In Foo, "s" is supposed to be a copy of "x" => the string should have a
ref count of 2, and the modification of x, should make a copy of the
string.
afaik the output should be "a" => but it is "X"
You can also set x:='' => which will be random in output
program Project1;
{$mode objfpc}{$H+}
var
x: String;
procedure Foo(const s: String);
begin
x[1]:='X'; // x:='';
writeln(s);
end;
procedure Bar;
begin
SetLength(x,1);
x[1]:= 'a';
end;
{$R *.res}
begin
Bar;
Foo(x);
readln;
end.
On 22/07/2010 03:10, Martin wrote:
I have an odd case (bug ?)
But I am unable to reproduce on a simple example.
Debugger output, and assembler both suggests it's in the compilation.
fpc from trunk a few weeks ago. using -OpPENTIUMM -O1
one procedure is declared as
procedure SetFoldState(const AValue: String);
another one calls this as follows
if FPendingFoldState <> '' then
SetFoldState(FPendingFoldState);
FPendingFoldState is a variable (String) of the object (both methods
belong to the same object too)
Now in SetFoldstate is a line:
FPendingFoldState:='';
and after this AValue becomes corrupt
The assembler of the calling code (from -al)
# [6541] if FPendingFoldState <> '' then
movl -4(%ebp),%eax
movl 1352(%eax),%eax
testl %eax,%eax
je .Lj12594
.Ll3371:
# [6542] SetFoldState(FPendingFoldState);
movl -4(%ebp),%eax
movl 1352(%eax),%edx
movl -4(%ebp),%eax
call SYNEDIT_TCUSTOMSYNEDIT_$__SETFOLDSTATE$ANSISTRING
.Lj12594:
There is no ansistring inc ref (both methods are in the same file, and
yes {$H+}
Trying to reproduce in a smaller example did not bring results....
Anyone any idea, if there s any code that could cause such an
"optimization" ?
Martin
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_______________________________________________
fpc-devel maillist - [email protected]
http://lists.freepascal.org/mailman/listinfo/fpc-devel
