Martin wrote:
I am still stuck on this issue.
I don't know if fpc_reraise has been entered while it should not; or if
the data was corrupted.
Normally you should be able to figure it out by examining the call
stack/backtrace.
What does FRAMETYPE = 1 mean?
Guess it is the value of FPC_EXCEPTION (trunk/rtl/inc/except.inc), the only currently
available/supported value for FrameType.
Should it expect an ExceptionObject? Should it be on top of the frame
list, when in fpc_reraise?
Or does it indicate that fpc_reraise was called where it should not have
been called?
What could trigger it to be called?
First, as the name suggests, it's triggered by a 'raise' keyword in a
try..except block.
Second, and more important, any try..finally block (including the implicit ones) contains a call to
fpc_reraise. It is translated into:
try
<body>
except
<finalization statements>
raise; <-- implies fpc_reraise
end;
Regards,
Sergei
On 09/06/2010 18:42, Martin wrote:
I am one tiny step forward..
The SigSegV happens in fpc_ReRaise; => but the actual error must have
been introduced further up.
Procedure fpc_ReRaise;[Public, Alias : 'FPC_RERAISE']; compilerproc;
var
_ExceptAddrStack : PExceptAddr;
begin
{$ifdef excdebug}
writeln ('In reraise');
{$endif}
_ExceptAddrStack:=ExceptAddrStack;
If _ExceptAddrStack=Nil then
DoUnHandledException;
ExceptObjectStack^.refcount := 0; //<<<<<<<<<<<<<<<<<
longjmp(_ExceptAddrStack^.Buf^,FPC_Exception);
end;
This is RTL (and compiled with -O1 => it doesn't use regvar), so I
should be able to trust variables here. (I also checked the assembler
view, and memory/registers...)
- ExceptObjectStack is nil => So the line marked raises a SigSegV.
- ExceptAddrStack is not nil => so DoUnHandledException was not called
The question is, any hints where to concentrate looking, in order to
find out, how this can end up with a nil pointer there?
The content of ExceptAddrStack
record TEXCEPTADDR {
BUF = $a3ef728,
NEXT = $a3ef768,
FRAMETYPE = 1}
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