MIPS16: Add R_MIPS16_PC16_S1 branch relocation support

For R_MIPS16_PC16_S1 the calculation is `(sign_extend(A) + S - P) >> 1'
and the usual MIPS16 bit shuffling applies to relocated field handling,
as per the encoding of the branch target in the extended form of the
MIPS16 B, BEQZ, BNEZ, BTEQZ and BTNEZ instructions.

	include/
	* elf/mips.h (R_MIPS16_PC16_S1): New relocation.

	bfd/
	* elf32-mips.c (elf_mips16_howto_table_rel): Add
	R_MIPS16_PC16_S1.
	(mips16_reloc_map): Likewise.
	* elf64-mips.c (mips16_elf64_howto_table_rel): Likewise.
	(mips16_elf64_howto_table_rela): Likewise.
	(mips16_reloc_map): Likewise.
	* elfn32-mips.c (elf_mips16_howto_table_rel): Likewise.
	(elf_mips16_howto_table_rela): Likewise.
	(mips16_reloc_map): Likewise.
	* elfxx-mips.c (mips16_branch_reloc_p): New function.
	(mips16_reloc_p): Handle R_MIPS16_PC16_S1.
	(b_reloc_p): Likewise.
	(mips_elf_calculate_relocation): Likewise.
	(_bfd_mips_elf_check_relocs): Likewise.
	* reloc.c (BFD_RELOC_MIPS16_16_PCREL_S1): New relocation.
	* bfd-in2.h: Regenerate.
	* libbfd.h: Regenerate.

	gas/
	* config/tc-mips.c (mips16_reloc_p): Handle
	BFD_RELOC_MIPS16_16_PCREL_S1.
	(b_reloc_p): Likewise.
	(limited_pcrel_reloc_p): Likewise.
	(md_pcrel_from): Likewise.
	(md_apply_fix): Likewise.
	(tc_gen_reloc): Likewise.
	(md_convert_frag): Likewise.
	(mips_fix_adjustable): Update comment.
	* testsuite/gas/mips/mips16-branch-reloc-2.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16-branch-reloc-3.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16-branch-addend-2.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16-branch-addend-3.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16-branch-absolute.d: Remove error
	output, add dump patterns.
	* testsuite/gas/mips/mips16-branch-reloc-2.l: Remove file.
	* testsuite/gas/mips/mips16-branch-reloc-3.l: Remove file.
	* testsuite/gas/mips/mips16-branch-addend-2.l: Remove file.
	* testsuite/gas/mips/mips16-branch-addend-3.l: Remove file.
	* testsuite/gas/mips/mips16-branch-absolute.l: Remove file.
	* testsuite/gas/mips/mips16-branch-addend-2.s: Add padding.
	* testsuite/gas/mips/branch-weak.s: Adjust alignment, avoid
	implicit instruction padding, avoid MIPS16 JR->JRC conversion.
	* testsuite/gas/mips/branch-weak-6.d: New test.
	* testsuite/gas/mips/branch-weak-7.d: New test.
	* testsuite/gas/mips/mips.exp: Run the new tests.

	ld/
	* testsuite/ld-mips-elf/mips16-branch-2.d: New test.
	* testsuite/ld-mips-elf/mips16-branch-3.d: New test.
	* testsuite/ld-mips-elf/mips16-branch-addend-2.d: New test.
	* testsuite/ld-mips-elf/mips16-branch-addend-3.d: New test.
	* testsuite/ld-mips-elf/mips16-branch.s: New test source.
	* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.

6 files changed, 98 insertions, 0 deletions

diff --git a/ld/testsuite/ld-mips-elf/mips-elf.exp b/ld/testsuite/ld-mips-elf/mips-elf.exp
index 8fb55e4..0d5842f 100644
--- a/ld/testsuite/ld-mips-elf/mips-elf.exp
+++ b/ld/testsuite/ld-mips-elf/mips-elf.exp
@@ -143,6 +143,11 @@ run_dump_test "mips16-1"
 # MIPS branch offset final link checking.
 run_dump_test "branch-misc-1"
 
+run_dump_test "mips16-branch-2" [list [list ld $abi_ldflags(o32)]]
+run_dump_test "mips16-branch-3" [list [list ld $abi_ldflags(o32)]]
+run_dump_test "mips16-branch-addend-2" [list [list ld $abi_ldflags(o32)]]
+run_dump_test "mips16-branch-addend-3" [list [list ld $abi_ldflags(o32)]]
+
 # Jalx test
 run_dump_test "jalx-1"
 
diff --git a/ld/testsuite/ld-mips-elf/mips16-branch-2.d b/ld/testsuite/ld-mips-elf/mips16-branch-2.d
new file mode 100644
index 0000000..9528733
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/mips16-branch-2.d
@@ -0,0 +1,19 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS16 link branch 2
+#source: ../../../gas/testsuite/gas/mips/mips16-branch-reloc-2.s
+#as: -EB -32
+#ld: -EB -Ttext 0x1c000000 -e bar
+
+.*: +file format .*mips.*
+
+Disassembly of section \.text:
+	\.\.\.
+[0-9a-f]+ <[^>]*> f000 1016 	b	1c001030 <bar>
+[0-9a-f]+ <[^>]*> f000 6014 	bteqz	1c001030 <bar>
+[0-9a-f]+ <[^>]*> f000 6112 	btnez	1c001030 <bar>
+[0-9a-f]+ <[^>]*> f000 2210 	beqz	v0,1c001030 <bar>
+[0-9a-f]+ <[^>]*> f000 2a0e 	bnez	v0,1c001030 <bar>
+[0-9a-f]+ <[^>]*> 6500      	nop
+	\.\.\.
+[0-9a-f]+ <[^>]*> 6500      	nop
+	\.\.\.
diff --git a/ld/testsuite/ld-mips-elf/mips16-branch-3.d b/ld/testsuite/ld-mips-elf/mips16-branch-3.d
new file mode 100644
index 0000000..88918c1
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/mips16-branch-3.d
@@ -0,0 +1,20 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS16 link branch 3
+#source: mips16-branch.s
+#source: ../../../gas/testsuite/gas/mips/mips16-branch-reloc-3.s
+#as: -EB -32
+#ld: -EB -Ttext 0x1c000000 -e bar
+
+.*: +file format .*mips.*
+
+Disassembly of section \.text:
+	\.\.\.
+[0-9a-f]+ <[^>]*> 6500      	nop
+	\.\.\.
+[0-9a-f]+ <[^>]*> f7fe 100e 	b	1c001000 <bar>
+[0-9a-f]+ <[^>]*> f7fe 600c 	bteqz	1c001000 <bar>
+[0-9a-f]+ <[^>]*> f7fe 610a 	btnez	1c001000 <bar>
+[0-9a-f]+ <[^>]*> f7fe 2208 	beqz	v0,1c001000 <bar>
+[0-9a-f]+ <[^>]*> f7fe 2a06 	bnez	v0,1c001000 <bar>
+[0-9a-f]+ <[^>]*> 6500      	nop
+	\.\.\.
diff --git a/ld/testsuite/ld-mips-elf/mips16-branch-addend-2.d b/ld/testsuite/ld-mips-elf/mips16-branch-addend-2.d
new file mode 100644
index 0000000..c724bdd
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/mips16-branch-addend-2.d
@@ -0,0 +1,19 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS16 link branch addend 2
+#source: ../../../gas/testsuite/gas/mips/mips16-branch-addend-2.s
+#as: -EB -32
+#ld: -EB -Ttext 0x1c000000 -e bar
+
+.*: +file format .*mips.*
+
+Disassembly of section \.text:
+	\.\.\.
+[0-9a-f]+ <[^>]*> f121 1010 	b	1c002264 <bar\+0x1234>
+[0-9a-f]+ <[^>]*> f121 600e 	bteqz	1c002264 <bar\+0x1234>
+[0-9a-f]+ <[^>]*> f121 610c 	btnez	1c002264 <bar\+0x1234>
+[0-9a-f]+ <[^>]*> f121 220a 	beqz	v0,1c002264 <bar\+0x1234>
+[0-9a-f]+ <[^>]*> f121 2a08 	bnez	v0,1c002264 <bar\+0x1234>
+[0-9a-f]+ <[^>]*> 6500      	nop
+	\.\.\.
+[0-9a-f]+ <[^>]*> 6500      	nop
+	\.\.\.
diff --git a/ld/testsuite/ld-mips-elf/mips16-branch-addend-3.d b/ld/testsuite/ld-mips-elf/mips16-branch-addend-3.d
new file mode 100644
index 0000000..84bccc7
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/mips16-branch-addend-3.d
@@ -0,0 +1,20 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS16 link branch addend 3
+#source: mips16-branch.s
+#source: ../../../gas/testsuite/gas/mips/mips16-branch-addend-3.s
+#as: -EB -32
+#ld: -EB -Ttext 0x1c000000 -e bar
+
+.*: +file format .*mips.*
+
+Disassembly of section \.text:
+	\.\.\.
+[0-9a-f]+ <[^>]*> 6500      	nop
+	\.\.\.
+[0-9a-f]+ <[^>]*> f100 1008 	b	1c002234 <foo\+0x214>
+[0-9a-f]+ <[^>]*> f100 6006 	bteqz	1c002234 <foo\+0x214>
+[0-9a-f]+ <[^>]*> f100 6104 	btnez	1c002234 <foo\+0x214>
+[0-9a-f]+ <[^>]*> f100 2202 	beqz	v0,1c002234 <foo\+0x214>
+[0-9a-f]+ <[^>]*> f100 2a00 	bnez	v0,1c002234 <foo\+0x214>
+[0-9a-f]+ <[^>]*> 6500      	nop
+	\.\.\.
diff --git a/ld/testsuite/ld-mips-elf/mips16-branch.s b/ld/testsuite/ld-mips-elf/mips16-branch.s
new file mode 100644
index 0000000..0024cdd
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/mips16-branch.s
@@ -0,0 +1,15 @@
+	.text
+	.globl	bar
+
+	.space	0x1000
+
+	.ent	bar
+	.set	mips16
+bar:
+	nop
+	.set	nomips16
+	.end	bar
+
+# Force some (non-delay-slot) zero bytes, to make 'objdump' print ...
+	.align	4, 0
+	.space	16