MIPS/BFD: Also handle `jalr $0, $25' with R_MIPS_JALR

Interpret the `jalr $0, $25' instruction encoding with an R_MIPS_JALR
relocation attached as an alias to `jr $25' and convert the jump to an
equivalent branch where possible, consequently covering the MIPSr6
architecture for the purpose of this optimization too.

	bfd/
	* elfxx-mips.c (mips_elf_perform_relocation): Also handle the
	`jalr $0, $25' instruction encoding.

	gas/
	* testsuite/gas/mips/jalr4.s: Add `jalr $0, $25' instructions.
	* testsuite/gas/mips/jalr4.d: Adjust accordingly.  Remove MIPSr6
	encoding patterns.
	* testsuite/gas/mips/jalr4-n64.d: Likewise.
	* testsuite/gas/mips/mipsr6@jalr4.d: New test.
	* testsuite/gas/mips/mipsr6@jalr4-n32.d: New test.
	* testsuite/gas/mips/mipsr6@jalr4-n64.d: New test.

	ld/
	* testsuite/ld-mips-elf/jalr4.dd: Adjust for `jalr $0, $25'
	instructions.
	* testsuite/ld-mips-elf/jalr4-r6.dd: New test.
	* testsuite/ld-mips-elf/mips-elf.exp: Run the new test.

7 files changed, 147 insertions, 6 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index b2908dc..ec6dbf7 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,13 @@
+2017-02-28  Maciej W. Rozycki  <macro@imgtec.com>
+
+	* testsuite/gas/mips/jalr4.s: Add `jalr $0, $25' instructions.
+	* testsuite/gas/mips/jalr4.d: Adjust accordingly.  Remove MIPSr6
+	encoding patterns.
+	* testsuite/gas/mips/jalr4-n64.d: Likewise.
+	* testsuite/gas/mips/mipsr6@jalr4.d: New test.
+	* testsuite/gas/mips/mipsr6@jalr4-n32.d: New test.
+	* testsuite/gas/mips/mipsr6@jalr4-n64.d: New test.
+
 2017-02-25  Alan Modra  <amodra@gmail.com>
 
 	* testsuite/gas/elf/strtab.s: Don't put directives on first
diff --git a/gas/testsuite/gas/mips/jalr4-n64.d b/gas/testsuite/gas/mips/jalr4-n64.d
index b61fc23..99a334d 100644
--- a/gas/testsuite/gas/mips/jalr4-n64.d
+++ b/gas/testsuite/gas/mips/jalr4-n64.d
@@ -11,7 +11,12 @@ Disassembly of section \.text:
 [ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
 [ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
 [0-9a-f]+ <[^>]*> 00000000 	nop
-[0-9a-f]+ <[^>]*> 0320000[89] 	jr	t9
+[0-9a-f]+ <[^>]*> 03200009 	jalr	zero,t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar0
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200008 	jr	t9
 [ 	]*[0-9a-f]+: R_MIPS_JALR	bar0
 [ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
 [ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
@@ -21,7 +26,12 @@ Disassembly of section \.text:
 [ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
 [ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
 [0-9a-f]+ <[^>]*> 00000000 	nop
-[0-9a-f]+ <[^>]*> 0320000[89] 	jr	t9
+[0-9a-f]+ <[^>]*> 03200009 	jalr	zero,t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar1
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200008 	jr	t9
 [ 	]*[0-9a-f]+: R_MIPS_JALR	bar1
 [ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
 [ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
@@ -31,7 +41,12 @@ Disassembly of section \.text:
 [ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
 [ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
 [0-9a-f]+ <[^>]*> 00000000 	nop
-[0-9a-f]+ <[^>]*> 0320000[89] 	jr	t9
+[0-9a-f]+ <[^>]*> 03200009 	jalr	zero,t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar2
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200008 	jr	t9
 [ 	]*[0-9a-f]+: R_MIPS_JALR	bar2
 [ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
 [ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
diff --git a/gas/testsuite/gas/mips/jalr4.d b/gas/testsuite/gas/mips/jalr4.d
index 1a1afdd..4cafd41 100644
--- a/gas/testsuite/gas/mips/jalr4.d
+++ b/gas/testsuite/gas/mips/jalr4.d
@@ -9,19 +9,28 @@ Disassembly of section \.text:
 [0-9a-f]+ <[^>]*> 0320f809 	jalr	t9
 [ 	]*[0-9a-f]+: R_MIPS_JALR	bar0
 [0-9a-f]+ <[^>]*> 00000000 	nop
-[0-9a-f]+ <[^>]*> 0320000[89] 	jr	t9
+[0-9a-f]+ <[^>]*> 03200009 	jalr	zero,t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar0
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200008 	jr	t9
 [ 	]*[0-9a-f]+: R_MIPS_JALR	bar0
 [0-9a-f]+ <[^>]*> 00000000 	nop
 [0-9a-f]+ <[^>]*> 0320f809 	jalr	t9
 [ 	]*[0-9a-f]+: R_MIPS_JALR	bar1
 [0-9a-f]+ <[^>]*> 00000000 	nop
-[0-9a-f]+ <[^>]*> 0320000[89] 	jr	t9
+[0-9a-f]+ <[^>]*> 03200009 	jalr	zero,t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar1
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200008 	jr	t9
 [ 	]*[0-9a-f]+: R_MIPS_JALR	bar1
 [0-9a-f]+ <[^>]*> 00000000 	nop
 [0-9a-f]+ <[^>]*> 0320f809 	jalr	t9
 [ 	]*[0-9a-f]+: R_MIPS_JALR	bar2
 [0-9a-f]+ <[^>]*> 00000000 	nop
-[0-9a-f]+ <[^>]*> 0320000[89] 	jr	t9
+[0-9a-f]+ <[^>]*> 03200009 	jalr	zero,t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar2
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200008 	jr	t9
 [ 	]*[0-9a-f]+: R_MIPS_JALR	bar2
 [0-9a-f]+ <[^>]*> 00000000 	nop
 	\.\.\.
diff --git a/gas/testsuite/gas/mips/jalr4.s b/gas/testsuite/gas/mips/jalr4.s
index 4ad6f26..25e8634 100644
--- a/gas/testsuite/gas/mips/jalr4.s
+++ b/gas/testsuite/gas/mips/jalr4.s
@@ -8,14 +8,20 @@ foo:
 	.reloc	1f, R_MIPS_JALR, bar0
 1:	jalr	$25
 	.reloc	1f, R_MIPS_JALR, bar0
+1:	jalr	$0, $25
+	.reloc	1f, R_MIPS_JALR, bar0
 1:	jr	$25
 	.reloc	1f, R_MIPS_JALR, bar1
 1:	jalr	$25
 	.reloc	1f, R_MIPS_JALR, bar1
+1:	jalr	$0, $25
+	.reloc	1f, R_MIPS_JALR, bar1
 1:	jr	$25
 	.reloc	1f, R_MIPS_JALR, bar2
 1:	jalr	$25
 	.reloc	1f, R_MIPS_JALR, bar2
+1:	jalr	$0, $25
+	.reloc	1f, R_MIPS_JALR, bar2
 1:	jr	$25
 	.end	foo
 
diff --git a/gas/testsuite/gas/mips/mipsr6@jalr4-n32.d b/gas/testsuite/gas/mips/mipsr6@jalr4-n32.d
new file mode 100644
index 0000000..0a17cbf
--- /dev/null
+++ b/gas/testsuite/gas/mips/mipsr6@jalr4-n32.d
@@ -0,0 +1,5 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS JALR reloc unaligned/cross-mode (n32)
+#as: -n32
+#source: jalr4.s
+#dump: mipsr6@jalr4.d
diff --git a/gas/testsuite/gas/mips/mipsr6@jalr4-n64.d b/gas/testsuite/gas/mips/mipsr6@jalr4-n64.d
new file mode 100644
index 0000000..b7424d6
--- /dev/null
+++ b/gas/testsuite/gas/mips/mipsr6@jalr4-n64.d
@@ -0,0 +1,57 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS JALR reloc unaligned/cross-mode (n64)
+#as: -64
+#source: jalr4.s
+
+.*: +file format .*mips.*
+
+Disassembly of section \.text:
+[0-9a-f]+ <[^>]*> 0320f809 	jalr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar0
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200009 	jr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar0
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200009 	jr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar0
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 0320f809 	jalr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar1
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200009 	jr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar1
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200009 	jr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar1
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 0320f809 	jalr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar2
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200009 	jr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar2
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200009 	jr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar2
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*
+[0-9a-f]+ <[^>]*> 00000000 	nop
+	\.\.\.
+	\.\.\.
+	\.\.\.
+	\.\.\.
diff --git a/gas/testsuite/gas/mips/mipsr6@jalr4.d b/gas/testsuite/gas/mips/mipsr6@jalr4.d
new file mode 100644
index 0000000..9b49339
--- /dev/null
+++ b/gas/testsuite/gas/mips/mipsr6@jalr4.d
@@ -0,0 +1,39 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS JALR reloc unaligned/cross-mode (o32)
+#as: -32
+#source: jalr4.s
+
+.*: +file format .*mips.*
+
+Disassembly of section \.text:
+[0-9a-f]+ <[^>]*> 0320f809 	jalr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar0
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200009 	jr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar0
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200009 	jr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar0
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 0320f809 	jalr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar1
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200009 	jr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar1
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200009 	jr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar1
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 0320f809 	jalr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar2
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200009 	jr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar2
+[0-9a-f]+ <[^>]*> 00000000 	nop
+[0-9a-f]+ <[^>]*> 03200009 	jr	t9
+[ 	]*[0-9a-f]+: R_MIPS_JALR	bar2
+[0-9a-f]+ <[^>]*> 00000000 	nop
+	\.\.\.
+	\.\.\.
+	\.\.\.
+	\.\.\.