S/390: Prevent GOT access rewrite for certain symbols

When dereferencing a GOT slot with lgrl or lg we rewrite this using
larl to get rid of the extra memory access.  However, we cannot do
this for:

- symbols marked for absolute addressing
- symbols at odd addresses (larl can handle only even addresses)

Fixed with the attached patch.

bfd/ChangeLog:

2018-09-17  Andreas Krebbel  <krebbel@linux.ibm.com>

	* elf64-s390.c (elf_s390_relocate_section): Prevent rewriting of
	GOT accesses with larl for ABS or misaligned symbols.

ld/ChangeLog:

2018-09-17  Andreas Krebbel  <krebbel@linux.ibm.com>

	* testsuite/ld-s390/gotreloc-1.s: Add tests for ABS and misaligned
	symbol. Move variables into data section. Make bar 8 bytes wide.
	* testsuite/ld-s390/gotreloc-1.ver: Make misaligned_sym resolve locally.
	* testsuite/ld-s390/gotreloc_31-1.dd: Adjust patterns.
	* testsuite/ld-s390/gotreloc_64-norelro-1.dd: Likewise.
	* testsuite/ld-s390/gotreloc_64-relro-1.dd: Likewise.

5 files changed, 32 insertions, 24 deletions

diff --git a/ld/testsuite/ld-s390/gotreloc-1.s b/ld/testsuite/ld-s390/gotreloc-1.s
index b60d6c1..0e1f6f7 100644
--- a/ld/testsuite/ld-s390/gotreloc-1.s
+++ b/ld/testsuite/ld-s390/gotreloc-1.s
@@ -1,4 +1,4 @@
-	.text
+.text
 	.globl foo
 foo:
 	lgrl	%r1,bar@GOTENT
@@ -6,6 +6,14 @@ foo:
 	lrl	%r1,bar@GOTENT
 	l	%r1,bar@GOT(%r12)
 	ly	%r1,bar@GOT(%r12)
+	lgrl	%r1,_GLOBAL_OFFSET_TABLE_@GOTENT
+	lgrl	%r1,misaligned_sym@GOTENT
 
+.data
 .globl	bar
-bar:	.long	0x123
+bar:	.quad	0x123
+
+.globl  misaligned_sym
+	.byte	1
+misaligned_sym:
+	.quad	42
diff --git a/ld/testsuite/ld-s390/gotreloc-1.ver b/ld/testsuite/ld-s390/gotreloc-1.ver
index 1cb06d6..0eb6096 100644
--- a/ld/testsuite/ld-s390/gotreloc-1.ver
+++ b/ld/testsuite/ld-s390/gotreloc-1.ver
@@ -1 +1 @@
-{ local: bar; };
+{ local: bar; misaligned_sym; };
diff --git a/ld/testsuite/ld-s390/gotreloc_31-1.dd b/ld/testsuite/ld-s390/gotreloc_31-1.dd
index 5e3f824..b1cf37c 100644
--- a/ld/testsuite/ld-s390/gotreloc_31-1.dd
+++ b/ld/testsuite/ld-s390/gotreloc_31-1.dd
@@ -4,10 +4,10 @@ tmpdir/gotreloc_31-1:     file format elf32-s390
 Disassembly of section .text:
 
 .* <foo>:
-.*:	c4 18 00 00 08 4e [	 ]*lgrl	%r1,118c <_GLOBAL_OFFSET_TABLE_\+0xc>
-.*:	e3 10 c0 0c 00 04 [	 ]*lg	%r1,12\(%r12\)
-.*:	c0 10 00 00 00 08 [	 ]*larl	%r1,10c <bar>
-.*:	58 10 c0 0c [	 ]*l	%r1,12\(%r12\)
-.*:	c0 10 00 00 00 03 [	 ]*larl	%r1,10c <bar>
-.* <bar>:
-.*:	00 00 01 23       	.long	0x00000123
+.*:	c4 18 00 00 08 56 [	 ]*lgrl	%r1,11b4 <_GLOBAL_OFFSET_TABLE_\+0x14>
+.*:	e3 10 c0 14 00 04 [	 ]*lg	%r1,20\(%r12\)
+.*:	c0 10 00 00 08 52 [	 ]*larl	%r1,11b8 <bar>
+.*:	58 10 c0 14 [	 ]*l	%r1,20\(%r12\)
+.*:	c0 10 00 00 08 4d [	 ]*larl	%r1,11b8 <bar>
+.*:	c4 18 00 00 08 46 [	 ]*lgrl	%r1,11b0 <_GLOBAL_OFFSET_TABLE_\+0x10>
+.*:	c4 18 00 00 08 41 [	 ]*lgrl	%r1,11ac <_GLOBAL_OFFSET_TABLE_\+0xc>
diff --git a/ld/testsuite/ld-s390/gotreloc_64-norelro-1.dd b/ld/testsuite/ld-s390/gotreloc_64-norelro-1.dd
index 8c8c619..8debd97 100644
--- a/ld/testsuite/ld-s390/gotreloc_64-norelro-1.dd
+++ b/ld/testsuite/ld-s390/gotreloc_64-norelro-1.dd
@@ -3,10 +3,10 @@ tmpdir/gotreloc_64-1:     file format elf64-s390
 Disassembly of section .text:
 
 .* <foo>:
-.*:	c0 10 00 00 00 0e [	 ]*larl	%r1,.* <bar>
-.*:	c0 10 00 00 00 0b [	 ]*larl	%r1,.* <bar>
-.*:	c4 1d 00 00 08 86 [	 ]*lrl	%r1,.* <_GLOBAL_OFFSET_TABLE_\+0x18>
-.*:	58 10 c0 18 [	 ]*l	%r1,24\(%r12\)
-.*:	e3 10 c0 18 00 58 [	 ]*ly	%r1,24\(%r12\)
-.* <bar>:
-.*:	00 00 01 23       	.long	0x00000123
+.*:	c0 10 00 00 08 9c [	 ]*larl	%r1,12e8 <bar>
+.*:	c0 10 00 00 08 99 [	 ]*larl	%r1,12e8 <bar>
+.*:	c4 1d 00 00 08 92 [	 ]*lrl	%r1,12e0 <_GLOBAL_OFFSET_TABLE_\+0x28>
+.*:	58 10 c0 28 [	 ]*l	%r1,40\(%r12\)
+.*:	e3 10 c0 28 00 58 [	 ]*ly	%r1,40\(%r12\)
+.*:	c4 18 00 00 08 86 [	 ]*lgrl	%r1,12d8 <_GLOBAL_OFFSET_TABLE_\+0x20>
+.*:	c4 18 00 00 08 7f [	 ]*lgrl	%r1,12d0 <_GLOBAL_OFFSET_TABLE_\+0x18>
diff --git a/ld/testsuite/ld-s390/gotreloc_64-relro-1.dd b/ld/testsuite/ld-s390/gotreloc_64-relro-1.dd
index 36f5001..64151d1 100644
--- a/ld/testsuite/ld-s390/gotreloc_64-relro-1.dd
+++ b/ld/testsuite/ld-s390/gotreloc_64-relro-1.dd
@@ -3,10 +3,10 @@ tmpdir/gotreloc_64-1:     file format elf64-s390
 Disassembly of section .text:
 
 .* <foo>:
-.*:	c0 10 00 00 00 0e [	 ]*larl	%r1,.* <bar>
-.*:	c0 10 00 00 00 0b [	 ]*larl	%r1,.* <bar>
-.*:	c4 1d 00 00 0f 1a [	 ]*lrl	%r1,.* <_GLOBAL_OFFSET_TABLE_\+0x18>
-.*:	58 10 c0 18 [	 ]*l	%r1,24\(%r12\)
-.*:	e3 10 c0 18 00 58 [	 ]*ly	%r1,24\(%r12\)
-.* <bar>:
-.*:	00 00 01 23       	.long	0x00000123
+.*:	c0 10 00 00 0f 0c [	 ]*larl	%r1,2000 <bar>
+.*:	c0 10 00 00 0f 09 [	 ]*larl	%r1,2000 <bar>
+.*:	c4 1d 00 00 0f 02 [	 ]*lrl	%r1,1ff8 <_GLOBAL_OFFSET_TABLE_\+0x28>
+.*:	58 10 c0 28 [	 ]*l	%r1,40\(%r12\)
+.*:	e3 10 c0 28 00 58 [	 ]*ly	%r1,40\(%r12\)
+.*:	c4 18 00 00 0e f6 [	 ]*lgrl	%r1,1ff0 <_GLOBAL_OFFSET_TABLE_\+0x20>
+.*:	c4 18 00 00 0e ef [	 ]*lgrl	%r1,1fe8 <_GLOBAL_OFFSET_TABLE_\+0x18>