Re: Mainline bootstrap failure (revision 110017)

[Kenneth Zadeck <zadeck at naturalbridge dot com>]

Daniel Berlin wrote:
> On Fri, 2006-01-20 at 10:53 +0530, Ranjit Mathew wrote:
>   
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > Hi,
> >
> >   Mainline fails to bootstrap for me (revision 110017)
> > on i686-pc-linux-gnu.
> >
> > Configured as:
> >
> > $GCC_SRC_DIR/configure --prefix=$HOME/gcc --enable-languages=c,c++,java \
> > - --with-as=/home/ranmath/gnu/bin/as --with-gnu-as \
> > - --with-ld=/home/ranmath/gnu/bin/ld --with-gnu-ld \
> > - --with-arch=pentium4 --with-tune=pentium4 \
> > - --disable-nls --disable-checking --disable-libmudflap \
> > - --disable-debug --enable-threads=posix --enable-__cxa_atexit \
> > - --disable-static
> >
> >     
>
>
> Kenny thought it would be nice, rather than pass the actual bb info to free to the freeing function, to instead pass some random bitmap.
>
>
> The attached fixes *that*, but this just causes a crash deeper in trying to free some chains.
>
> However, it looks like that is either caused by a double free, or because
>  we never null out pointers to things after we free the memory for what they are pointing to.
>
>   
> ------------------------------------------------------------------------
>
> Index: df-core.c
> ===================================================================
> --- df-core.c	(revision 110017)
> +++ df-core.c	(working copy)
> @@ -292,6 +292,7 @@ are write-only operations.  
>  static struct df *ddf = NULL;
>  struct df *shared_df = NULL;
>  
> +static void * df_get_bb_info (struct dataflow *, unsigned int);
>  /*----------------------------------------------------------------------------
>    Functions to create, destroy and manipulate an instance of df.
>  ----------------------------------------------------------------------------*/
> @@ -370,7 +371,7 @@ df_set_blocks (struct df *df, bitmap blo
>  		  EXECUTE_IF_SET_IN_BITMAP (diff, 0, bb_index, bi)
>  		    {
>  		      basic_block bb = BASIC_BLOCK (bb_index);
> -		      (*dflow->problem->free_bb_fun) (dflow, bb, diff);
> +		      (*dflow->problem->free_bb_fun) (dflow, bb, df_get_bb_info (dflow, bb_index));
>  		    }
>  		}
>  	    }
>   
This is why c sucks.  In any language with a reasonable type system, 
this could have been written with a subtype and would not require using 
a void * arg.

Sorry for the problems and thanks for looking into them.

kenny