Fix forced allocation of common (-d) during -r links.

If the .bss section has other data in it besides common allocations,
gold was subtracting the wrong section start address from the symbol
value.

gold/
	PR gold/20976
	* symtab.cc (Symbol_table::sized_write_globals): Use address of
	output section, not input section.
	* testsuite/Makefile.am (pr20976): New test case.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/pr20976.c: New source file.

1 files changed, 34 insertions, 0 deletions

diff --git a/gold/testsuite/pr20976.c b/gold/testsuite/pr20976.c
new file mode 100644
index 00000000000..353e749205a
--- /dev/null
+++ b/gold/testsuite/pr20976.c
@@ -0,0 +1,34 @@
+/* pr20976.c -- test forced common allocation
+
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   Written by Cary Coutant <ccoutant@gmail.com>
+
+   This file is part of gold.
+
+   This program 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 3 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., 51 Franklin Street - Fifth Floor, Boston,
+   MA 02110-1301, USA.
+
+   This test checks that forced common allocation (-d) with -r
+   produces the correct result when the .bss section contains
+   other allocated data besides common symbols. */
+
+int a = 0;
+int b;
+
+int main(void)
+{
+  a = 1;
+  return b;
+}