Use signed data type for R_XTENSA_DIFF* relocation offsets.

R_XTENSA_DIFF relocation offsets are in fact signed. Treat them as such.
Add testcase that examines ld behaviour on R_XTENSA_DIFF relocation
changing sign during relaxation.

2014-05-02  Volodymyr Arbatov  <arbatov@cadence.com>
	    David Weatherford  <weath@cadence.com>
	    Max Filippov  <jcmvbkbc@gmail.com>

bfd/
  * elf32-xtensa.c (relax_section): treat R_XTENSA_DIFF* relocations as
  signed.

gas/
  * config/tc-xtensa.c (md_apply_fix): mark BFD_RELOC_XTENSA_DIFF*
  fixups as signed.

ld/testsuite/
  * ld-xtensa/diff_overflow.exp, * ld-xtensa/diff_overflow1.s,
  * ld-xtensa/diff_overflow2.s: Add test for DIFF* relocation
  signedness and overflow checking.

4 files changed, 100 insertions, 0 deletions

diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index cc29297..7564025 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2014-05-02  Max Filippov  <jcmvbkbc@gmail.com>
+
+	* ld-xtensa/diff_overflow.exp, * ld-xtensa/diff_overflow1.s,
+	* ld-xtensa/diff_overflow2.s: Add test for DIFF* relocation
+	signedness and overflow checking.
+
 2014-05-01  Hans-Peter Nilsson  <hp@bitrange.com>
 
 	* ld-mmix/sec-11.d, ld-mmix/sec-11.ld, ld-mmix/sec-10.s,
diff --git a/ld/testsuite/ld-xtensa/diff_overflow.exp b/ld/testsuite/ld-xtensa/diff_overflow.exp
new file mode 100644
index 0000000..89deb38
--- /dev/null
+++ b/ld/testsuite/ld-xtensa/diff_overflow.exp
@@ -0,0 +1,45 @@
+# Test DIFF* relocation signedness and overflow checking
+# By Max Filippov, Cadence Design Systems, Inc.
+#   Copyright (C) 2014 Free Software Foundation, Inc.
+#
+# This file is part of the GNU Binutils.
+#
+# 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.
+
+if ![istarget "xtensa*-*-*"] {
+    return
+}
+
+set testname "DIFF_OVERFLOW"
+
+if ![ld_assemble $as "--text-section-literals $srcdir/$subdir/diff_overflow1.s" tmpdir/diff_overflow1.o] {
+    unresolved $testname
+    return
+}
+if ![ld_assemble $as "--text-section-literals $srcdir/$subdir/diff_overflow2.s" tmpdir/diff_overflow2.o] {
+    unresolved $testname
+    return
+}
+
+set object "tmpdir/diff_overflow"
+
+if ![ld_simple_link $ld $object "tmpdir/diff_overflow1.o tmpdir/diff_overflow2.o"] {
+    verbose -log "failure in ld"
+    fail $testname
+    return
+}
+
+pass $testname
diff --git a/ld/testsuite/ld-xtensa/diff_overflow1.s b/ld/testsuite/ld-xtensa/diff_overflow1.s
new file mode 100644
index 0000000..38519da
--- /dev/null
+++ b/ld/testsuite/ld-xtensa/diff_overflow1.s
@@ -0,0 +1,27 @@
+	.section .text.f0,"axG",@progbits,f0,comdat
+	.literal_position
+	.literal .L0, 0
+	.align 4
+f0:
+	entry	a1, 32
+	l32r	a2, .L0
+	retw
+
+	.section .text
+	.literal_position
+	.global _start
+_start:
+	entry	a1, 32
+	retw
+
+	.section .text.f1,"axG",@progbits,f1,comdat
+	.literal_position
+	.literal .L1, 0
+	.literal .L2, 0
+	.align 4
+	.global	f1
+f1:
+	entry	a1, 32
+	l32r	a2, .L1
+	l32r	a3, .L2
+	retw
diff --git a/ld/testsuite/ld-xtensa/diff_overflow2.s b/ld/testsuite/ld-xtensa/diff_overflow2.s
new file mode 100644
index 0000000..096ae39
--- /dev/null
+++ b/ld/testsuite/ld-xtensa/diff_overflow2.s
@@ -0,0 +1,22 @@
+	.section .text.f1,"axG",@progbits,f1,comdat
+	.literal_position
+	.literal .L5, 0
+	.align	4
+f4:
+	entry	a1, 32
+.Lf4:
+	l32r	a2, .L5
+	l32r	a2, .L5
+	nop
+	nop
+	retw
+
+	.section .text
+f5:
+	entry	a1, 32
+.Lf5:
+	retw
+
+	.section .debug_frame,"",@progbits
+	.byte	.Lf4 - f4
+	.byte	.Lf5 - f5