PATCH COMMITTED: Fix gold common symbol sorting

[Ian Lance Taylor <iant at google dot com>]

I made a dumb mistake in the sorting routine for the common symbols.
I noticed it because the instable sorting routine caused a linker
segmentation fault in one of the gcc test cases.

I committed this patch to fix it, with a test case.

Ian


2008-03-27  Ian Lance Taylor  <iant@google.com>

	* common.cc (Sort_commons::operator): Correct sorting algorithm.
	* testsuite/common_test_1.c: New file.
	* testsuite/Makefile.am (check_PROGRAMS): Add common_test_1.
	(common_test_1_SOURCES): New variable.
	(common_test_1_DEPENDENCIES): New variable.
	(common_test_1_LDFLAGS): New variable.


Index: common.cc
===================================================================
RCS file: /cvs/src/src/gold/common.cc,v
retrieving revision 1.14
diff -p -u -r1.14 common.cc
--- common.cc	13 Mar 2008 21:04:21 -0000	1.14
+++ common.cc	27 Mar 2008 19:54:43 -0000
@@ -93,19 +93,21 @@ Sort_commons<size>::operator()(const Sym
   const Sized_symbol<size>* psa = symtab->get_sized_symbol<size>(pa);
   const Sized_symbol<size>* psb = symtab->get_sized_symbol<size>(pb);
 
+  // Sort by largest size first.
   typename Sized_symbol<size>::Size_type sa = psa->symsize();
   typename Sized_symbol<size>::Size_type sb = psb->symsize();
   if (sa < sb)
     return false;
-  else if (sb > sa)
+  else if (sb < sa)
     return true;
 
-  // When the symbols are the same size, we sort them by alignment.
+  // When the symbols are the same size, we sort them by alignment,
+  // largest alignment first.
   typename Sized_symbol<size>::Value_type va = psa->value();
   typename Sized_symbol<size>::Value_type vb = psb->value();
   if (va < vb)
     return false;
-  else if (vb > va)
+  else if (vb < va)
     return true;
 
   // Otherwise we stabilize the sort by sorting by name.
Index: testsuite/Makefile.am
===================================================================
RCS file: /cvs/src/src/gold/testsuite/Makefile.am,v
retrieving revision 1.49
diff -p -u -r1.49 Makefile.am
--- testsuite/Makefile.am	27 Mar 2008 18:19:09 -0000	1.49
+++ testsuite/Makefile.am	27 Mar 2008 19:54:43 -0000
@@ -277,6 +277,10 @@ two_file_mixed_2_shared_test_LDADD = two
 
 endif FN_PTRS_IN_SO_WITHOUT_PIC
 
+check_PROGRAMS += common_test_1
+common_test_1_SOURCES = common_test_1.c
+common_test_1_DEPENDENCIES = gcctestdir/ld
+common_test_1_LDFLAGS = -Bgcctestdir/
 
 check_PROGRAMS += exception_test
 check_PROGRAMS += exception_static_test
Index: testsuite/common_test_1.c
===================================================================
RCS file: testsuite/common_test_1.c
diff -N testsuite/common_test_1.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/common_test_1.c	27 Mar 2008 19:54:43 -0000
@@ -0,0 +1,75 @@
+/* common_test_1.c -- test common symbol sorting
+
+   Copyright 2008 Free Software Foundation, Inc.
+   Written by Ian Lance Taylor <iant@google.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 is a test of a common symbol in the main program and a
+   versioned symbol in a shared library.  The common symbol in the
+   main program should override the shared library symbol.  */
+
+#include <assert.h>
+
+/* Common symbols should be sorted by size, largest first, and then by
+   alignment, largest first.  We mix up the names, because gas seems
+   to sort common symbols roughly by name.  */
+
+int c9[90];
+int c8[80];
+int c7[70];
+int c6[60];
+int c5[10];
+int c4[20];
+int c3[30];
+int c2[40];
+int c1[50];
+
+int a1 __attribute__ ((aligned (1 << 9)));
+int a2 __attribute__ ((aligned (1 << 8)));
+int a3 __attribute__ ((aligned (1 << 7)));
+int a4 __attribute__ ((aligned (1 << 6)));
+int a5 __attribute__ ((aligned (1 << 1)));
+int a6 __attribute__ ((aligned (1 << 2)));
+int a7 __attribute__ ((aligned (1 << 3)));
+int a8 __attribute__ ((aligned (1 << 4)));
+int a9 __attribute__ ((aligned (1 << 5)));
+
+int
+main (int argc __attribute__ ((unused)), char** argv __attribute__ ((unused)))
+{
+  assert (c5 > c4);
+  assert (c4 > c3);
+  assert (c3 > c2);
+  assert (c2 > c1);
+  assert (c1 > c6);
+  assert (c6 > c7);
+  assert (c7 > c8);
+  assert (c8 > c9);
+
+  assert (&a1 < &a2);
+  assert (&a2 < &a3);
+  assert (&a3 < &a4);
+  assert (&a4 < &a9);
+  assert (&a9 < &a8);
+  assert (&a8 < &a7);
+  assert (&a7 < &a6);
+  assert (&a6 < &a5);
+
+  return 0;
+}