Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!AI.MIT.EDU!kingdon
From: kingdon@AI.MIT.EDU (Jim Kingdon)
Newsgroups: gnu.gdb.bug
Subject: gdb3.5 & malloc(3c)
Message-ID: <9002261822.AA00297@pogo>
Date: 26 Feb 90 18:22:44 GMT
References: <31297@bigtex.cactus.org>
Sender: daemon@tut.cis.ohio-state.edu
Distribution: gnu
Organization: GNUs Not Usenet
Lines: 24

OK, kids, here's the story on malloc().  GDB 3.5, if built as
distributed makes 4088 byte malloc's in obstack.c.  This is very bad,
because such a GDB uses the range-checking version of malloc, which
causes 4088 byte requests to in fact occupy 8192 bytes.  The next
release of GDB 3 will fix this by using 4072 byte requests instead.

Mike Haertel has written a new malloc for GNU, which will be used in
GDB version 4 (and emacs version 19).  I'm not distributing it in GDB
version 3 because it has not been extensively tested and therefore
might be buggy.

    gdb doesn't have a bug as far as I am concerned, although one fix
    might be to use a special "malloc" for reading in the symbol table, or
    to just use brk(2).

Obstacks are used for the symbol table, which (if the bug described
above is fixed) supposedly should provide good performance.  Not that
I'm sure anyone has looked at it closely for improvements in memory
usage.

    In the meantime, someone should volunteer to fix GNU malloc.

I guess if people want to play with the new GNU malloc I can make a
copy available for FTP.  Send me mail if interested.