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From: othar@CS.UCLA.EDU (Othar Hansson)
Newsgroups: gnu.g++.bug
Subject: alloca's in ld.c cause seg-faults
Message-ID: <8903200402.AA26265@maui.cs.ucla.edu>
Date: 20 Mar 89 04:02:45 GMT
Sender: daemon@tut.cis.ohio-state.edu
Reply-To: othar@cs.ucla.edu
Distribution: gnu
Organization: Weapons Division, Pepperidge Farm
Lines: 24



In "GNU C++ version 1.34.1 (68k, MIT Syntax) 
compiled by GNU C version 1.34" on a SUN 3, ...

ld++ exits with a segmentation fault when fed source files with large
data segments.  The fault is caused by an attempt to 'alloca' a large
chunk of memory in 'copy_data()' in ld.c

	bytes = (char *) alloca (entry->header.a_data);

if a_data is too big (e.g. 950k) to fit on the call stack, then alloca
returns garbage, apparently.  Allocating using malloc() (with a
corresponding 'free(bytes)') fixes the problem, but alloca is used in
similarly dangerous contexts elsewhere.

Please don't ask how ugly my program must be 
to have a data segment of 950k :-)


Othar Hansson

( othar@cs.ucla.edu
..!{ucbvax|rutgers}!ucla-cs!othar )