Re: binutils 2.9.1 gas problem (growing frags)

[Ian Lance Taylor <ian@airs.com>]

   Date: Thu, 10 Jun 1999 11:40:19 -0700 (PDT)
   From: Vaughan Hillman <hillman_97@yahoo.com>

   It appears that the assembler is reading in the stab
   entries from file.s and putting them into an obstack.
   Initially it allocates a frag with 4096 bytes to 
   start off with.  When line 184 of file.s is read in
   the function frag_grow() is called to see if this line
   can be read into the current frag. frag_grow is told
   to grow by 91 bytes.  The current obstack has 88 bytes
   free (chunk_limit-next_free).  frag_new() goes and
   takes care of the allocation by calling frag_alloc().
   Here obstack_alloc() is called.   It goes and
   allocates a frag for the stack.  Since obstack_alloc
   is told to allocate SIZEOF_STRUCT_FRAG (which happens
   to be 84 bytes) bytes, obstack_blank returns saying
   that there was enough space for the 84 bytes (as we
   have 88 bytes free) and adds in the new frag header
   leaving 4 bytes. We return to frag_grow() having not
   allocated a larger frag and the code calls frag_new()
   again.  This time obstack_blank() allows
   _obstack_newchunk() to be called since we are asking
   for 84 bytes and have 4 bytes free.
   It returns with 168 bytes and the 84 byte header is
   taken out again leaving us with 84 bytes.  The code in
   frag_grow then exits saying that it was unsucessfull
   at getting any more memory added to the obstack.

I think this problem has been fixed since the 2.9.1 release.  Look at
the current version of frag_grow in frags.c.

If you can't get CVS to work for you, use the cvsweb interface.  For
example, the current frags.c can be seen at
    http://sourceware.cygnus.com/cgi-bin/cvsweb.cgi/binutils/gas/frags.c?rev=1.1.1.1 &content-type=text/x-cvsweb-markup&cvsroot=binutils

Ian