[PATCH] orphan section creating huge output file

[Bob Wilson <bwilson at tensilica dot com>]

A while back, David Heine found a problem where an orphan section could cause 
the linker to create huge output files, or even segfault when trying to seek to 
a negative value.  (See http://sourceware.org/ml/binutils/2003-04/msg00423.html) 
 This problem was fixed earlier, but now he's found a similar problem.

David analyzed this and sent me an earlier version of this patch, so I'll try to 
describe this as best I can.  The use of IGNORE_SECTION in 
lang_size_sections_1() in ldlang.c is not right because at that point the 
section sizes are all zero, and IGNORE_SECTION is true for zero size sections. 
Moreover, even a zero size section can cause the huge output file problem.  The 
attached patch moves the check for zero size sections out of the IGNORE_SECTION 
macro.  David also provided a testcase to demonstrate the problem, and I've 
cleaned it up and added it to the testsuite.

OK for mainline?


ld/ChangeLog:

2005-03-16  David Heine  <dlheine@tensilica.com>
            Bob Wilson  <bob.wilson@acm.org>

        * ldlang.c (IGNORE_SECTION): Remove check for zero size.
        (lang_check_section_addresses): Ignore zero size sections here.

ld/testsuite/ChangeLog:

2005-03-16  David Heine  <dlheine@tensilica.com>
            Bob Wilson  <bob.wilson@acm.org>

        * ld-scripts/empty-orphan.d, ld-scripts/empty-orphan.exp,
        ld-scripts/empty-orphan.s, ld-scripts/emtpy-orphan.t: New test.

Index: ldlang.c
===================================================================
RCS file: /cvs/src/src/ld/ldlang.c,v
retrieving revision 1.174
diff -u -p -r1.174 ldlang.c
--- ldlang.c	16 Mar 2005 21:52:42 -0000	1.174
+++ ldlang.c	17 Mar 2005 01:56:12 -0000
@@ -3300,8 +3300,7 @@ size_input_section
   ((s->flags & SEC_NEVER_LOAD) != 0				\
    || (s->flags & SEC_ALLOC) == 0				\
    || ((s->flags & SEC_THREAD_LOCAL) != 0			\
-	&& (s->flags & SEC_LOAD) == 0)				\
-   || s->size == 0)
+	&& (s->flags & SEC_LOAD) == 0))
 
 /* Check to see if any allocated sections overlap with other allocated
    sections.  This can happen if a linker script specifies the output
@@ -3318,7 +3317,7 @@ lang_check_section_addresses (void)
       asection *os;
 
       /* Ignore sections which are not loaded or which have no contents.  */
-      if (IGNORE_SECTION (s))
+      if (IGNORE_SECTION (s) || s->size == 0)
 	continue;
 
       /* Once we reach section 's' stop our seach.  This prevents two
@@ -3332,7 +3331,7 @@ lang_check_section_addresses (void)
 	  bfd_vma os_end;
 
 	  /* Only consider loadable sections with real contents.  */
-	  if (IGNORE_SECTION (os))
+	  if (IGNORE_SECTION (os) || os->size == 0)
 	    continue;
 
 	  /* We must check the sections' LMA addresses not their
--- /dev/null	2005-03-03 02:28:48.304630480 -0800
+++ ld/testsuite/ld-scripts/empty-orphan.d	2005-03-16 17:46:07.037852112 -0800
@@ -0,0 +1,3 @@
+#source: empty-orphan.s
+#ld: -T empty-orphan.t
+#error: no memory region specified for loadable section
--- /dev/null	2005-03-03 02:28:48.304630480 -0800
+++ ld/testsuite/ld-scripts/empty-orphan.exp	2005-03-16 17:51:55.112721910 -0800
@@ -0,0 +1,27 @@
+# Make sure orphan sections do not lead to huge output files.
+# By David Heine, Tensilica, Inc.
+#   Copyright 2005
+#   Free Software Foundation, Inc.
+#
+# This file is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+# PHDRS is only meaningful for ELF.
+if ![is_elf_format] {
+    return
+}
+
+set testname "empty-orphan"
+
+run_dump_test empty-orphan
--- /dev/null	2005-03-03 02:28:48.304630480 -0800
+++ ld/testsuite/ld-scripts/empty-orphan.s	2005-03-16 17:55:04.674395168 -0800
@@ -0,0 +1,4 @@
+	.section .orphan_data, "a"
+	# empty but defined
+	.section .data
+	.word 0x1111
--- /dev/null	2005-03-03 02:28:48.304630480 -0800
+++ ld/testsuite/ld-scripts/empty-orphan.t	2005-03-16 17:55:14.630905387 -0800
@@ -0,0 +1,21 @@
+MEMORY
+{
+  default_mem : ORIGIN = 0x0, LENGTH = 0x100000
+  text_mem : ORIGIN = 0x60000000, LENGTH = 0x100
+  data_mem : ORIGIN = 0x70000000, LENGTH = 0x100
+}
+
+PHDRS
+{
+  default_phdr PT_LOAD;
+  text_phdr PT_LOAD;
+  data_phdr PT_LOAD;
+}
+
+SECTIONS
+{
+   .text : { *(.text) } > text_mem : text_phdr
+   .data : { *(.data) } > data_mem : data_phdr
+   .bss : { *(.bss) } > data_mem : data_phdr
+   /* .orphan_data is an orphan */
+}