[fpc-devel] assert, and the frame/addr for the exception.

Martin lazarus at mfriebe.de
Sat May 7 01:18:04 CEST 2011

I was looking at http://bugs.freepascal.org/view.php?id=19113
And also http://bugs.freepascal.org/view.php?id=12528

Looking at the assembler code of assert (without utrace), it seems that 
the "assert" statement, pushes ebp (the current frame) on the argument list.
   assert(false, 'xxx');
004286A8 55                       push   %ebp             // TheAddr
004286A9 b92a000000               mov    $0x2a,%ecx     // LineNo
004286AE ba00455600               mov    $0x564500,%edx     // FN
004286B3 b80c455600               mov    $0x56450c,%eax     //  Msg
004286B8 e8834afeff               call   0x40d140 <fpc_assert>

but then
   Procedure AssertErrorHandler (Const Msg,FN : 
ShortString;LineNo:longint; TheAddr : pointer);
   Var  S : String;
     If Msg='' then     S:=SAssertionFailed  else     S:=Msg;
     Raise EAssertionFailed.Createfmt(SAssertError,[S,Fn,LineNo]) at 

Seems to hand that over as the address pointer to the code?
So the exception will have a frame of 0x0, and a code pointer to some 
none executable part?

Maybe I am wrong, but something does seem to be incorrect?


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