Re: Constant pool overflow (PATCH)

Sorry, MAXCONSTANTPOOLITEMS should be 65535, not 256 !
Will work anyway, but output will be a little bit bigger.

As for MAXCONSTANTPOOLSIZE the limit is actually on the
actions itself (65535), while the check is made against size
of all string costants (including trailing 0). If anybody
knows more about this latter limit (what is included in the action
and what is not) please let me know so that value can be tweeked.
For now I kept 2 bytes but I really don't know wheter its enaugh,
or too much.

> +#define MAXCONSTANTPOOLITEMS 65535
> +/* 2bytes are for the lenght field */
> +#define MAXCONSTANTPOOLSIZE 65533

--strk;

strk wrote:
> This patch should fix the problem
> (if I didn't allow too many bytes in the introduced limits)
> 
> --strk;
> 
> -----------------8<------------------------ cut here ------------
> 
> diff -rU2 ming.000/src/actioncompiler/compile.c ming/src/actioncompiler/compile.c
> --- ming.000/src/actioncompiler/compile.c       Wed Sep 17 15:57:10 2003
> +++ ming/src/actioncompiler/compile.c   Wed Sep 17 19:17:41 2003
> @@ -29,5 +29,5 @@
>  #include "compile.h"
> 
> -static int nConstants = {0}, maxConstants = {0};
> +static int nConstants = {0}, maxConstants = {0}, sizeConstants = {0};
>  static char **constants;
> 
> @@ -121,7 +121,19 @@
>         }
> 
> +       /* Don't let constant pool biggern then allowed */
> +       if ( sizeConstants+strlen(s)+1 > MAXCONSTANTPOOLSIZE ) return -1;
> +
>         if(nConstants == maxConstants)
> -               constants = (char **) realloc(constants, (maxConstants += 64) * sizeof(char *));
> +       {
> +               /* Do not allow for more then MAXCONSTANTPOOLITEMS constants */
> +               if ( nConstants+1 == MAXCONSTANTPOOLITEMS ) return -1;
> +               if ( maxConstants+64 > MAXCONSTANTPOOLITEMS )
> +                       maxConstants += 64;
> +               else maxConstants = MAXCONSTANTPOOLITEMS;
> +               constants = (char **) realloc(constants, maxConstants * sizeof(char *));
> +       }
> +
>         constants[nConstants] = strdup(s);
> +       sizeConstants += (strlen(s)+1);
>         return nConstants++;
>  }
> diff -rU2 ming.000/src/actioncompiler/compile.h ming/src/actioncompiler/compile.h
> --- ming.000/src/actioncompiler/compile.h       Wed Sep 17 15:57:10 2003
> +++ ming/src/actioncompiler/compile.h   Wed Sep 17 19:16:43 2003
> @@ -118,4 +118,7 @@
>  int addConstant(const char *s);
>  int bufferWriteConstants(Buffer out);
> +#define MAXCONSTANTPOOLITEMS 256
> +/* 2bytes are for the lenght field */
> +#define MAXCONSTANTPOOLSIZE 65533
> 
>  /* write data to buffer */
> 
> -----------------8<------------------------ cut here ------------
> 
> strk wrote:
> > Hello,
> > I'm having a constant pool overflow problems with Ming (latest CVS).
> > The problem seems to be exactly described here:
> > 
> > from: http://www.nowrap.de/flasm.html
> > --8<---------------------------------
> > While it's good practice to keep scripts smaller than 64k (compiled) per
> > frame, it's possible to get larger. But the sole action record - constants,
> > push, function and other is limited to 64k because of 2 bytes length field
> > size.
> > 
> > Since flash will create (in 99% of cases) the constant pool for all
> > variables and methods, overflow is possible.
> > 
> > It's a pity flash itself doesn't tell you the script is too big.
> > Instead flash compiler writes overflowed value to the length field without
> > errors or warnings. If you try to execute the swf, flash player crashes,
> > or actions are omitted. flasm will stop disassembling with an error message
> > if such overflowed constant pool definition is
> > encountered in swf.
> > --8<---------------------------------
> > 
> > I know this is the problem because flasm (as in the last statement)
> > stops and dumps the error: Too many constants. The output of course
> > is corrupted (action scrambled don't know how - missing variables),
> > while the same actionscript file compiled with MX gives successful
> > result.
> > 
> > This document refers to the flash authoring environment prior to MX.
> > MX corrects this.
> > 
> > What about Ming ?
> > 
> > --strk;
> > _______________________________________________
> > ming-fun mailing list
> > [email protected]
> > http://www.opaque.net/mailman/listinfo/ming-fun
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