[sdcc-devel] [ sdcc-Bugs-613998 ] Crash or bad code in Win98. Ok in WinXP.

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Bugs item #613998, was opened at 2002-09-24 20:21
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Category: C-Front End
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Jesus Calvino-Fraga (jesusc)
Assigned to: Johan Knol (johanknol)
Summary: Crash or bad code in Win98. Ok in WinXP.

Initial Comment:
When compiling the file 'parse.c' (sdcc -c parse.c) sdcc crashes or generates bad code on Windows 
95/98 but works ok in Windows 2k/XP.  Adding or removing random code in 'parse.c' will cause sdcc to 
crash, generate wrong code, or even generate correct code under Windows 95/98.  When line 'char j=0;' 
is commented out in 'parse.c' sdcc was crashing in my Windows 98 machine, but it may just generate 
bad code in Windows 95.   I am using the latest CVS sources compiled with Visual C++ 6.0.  I used the 
same executable when testing on the four machines.  It doesn't matter if I build sdcc on any of the four 
machines the result is the same.  When sdcc crashes it points to either sdcc\src\SDCCloop.c:214 or 
sdcc\src\SDCCloop.c:216:

int 
findLoopEndSeq (region * lreg)
{
  eBBlock *block;
  eBBlock *lblock;

  for (block = lblock = setFirstItem (lreg->regBlocks); block;
       block = setNextItem (lreg->regBlocks))
    {
      if (block != lblock && block->lSeq > lblock->lSeq)  <--  CRASHES HERE
	lblock = block;
    }

	   return lblock->lSeq <-- OR CRASHES HERE
}

And the problem is that either block or lblock are invalid, for example lblock=0x00000194.  I am also 
including the asm listing when compiling in Windows 98 and Windows XP, in one of the many occasions 
where the generated code was different.  If I change the code in SDCCloop.c so that it checks for block 
and lblock to be larger than (eBBlock *)0x1000 sdcc doesn't crash but it generates bad code.




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>Comment By: Johan Knol (johanknol)
Date: 2003-02-04 22:11

Message:
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I can't reproduce the crash, and diffing the two asm's doesn't 
help much either. Please point me at where in the c and asm 
file it goes wrong (it's too long to reverse engineer :), there 
should be other symtoms as well in the dumpfiles.
These are the most difficult bugs to find, really. Most likely an 
enum that starts at 0, so: uninitialized equals zero where it 
should be undefined!

Johan
(how about rewriting sdcc in c++ :)


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Comment By: Jesus Calvino-Fraga (jesusc)
Date: 2003-02-04 21:06

Message:
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The problem still exists.

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Comment By: Johan Knol (johanknol)
Date: 2003-02-04 18:10

Message:
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user_id=63512

I think my fix for bug #631653 fixed this too. If you can 
confirm, please close the bug.

Johan

----------------------------------------------------------------------

Comment By: Jesus Calvino-Fraga (jesusc)
Date: 2003-01-27 17:52

Message:
Logged In: YES 
user_id=603650

Yes, it still exists.  The debugger breaks at SDCCloop.c:218.


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Comment By: Johan Knol (johanknol)
Date: 2003-01-27 09:47

Message:
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user_id=63512

Can you confirm this still exists in latest cvs?


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