MIPS/GAS: Keep the ISA bit in the addend of branch relocations

Correct a problem with the ISA bit being stripped from the addend of
compressed branch relocations, affecting RELA targets.  It has been
there since microMIPS support has been added, with:

commit df58fc944dbc6d5efd8d3826241b64b6af22f447
Author: Richard Sandiford <rdsandiford@googlemail.com>
Date:   Sun Jul 24 14:20:15 2011 +0000

<https://sourceware.org/ml/binutils/2011-07/msg00198.html>, ("MIPS:
microMIPS ASE support") and R_MICROMIPS_PC7_S1, R_MICROMIPS_PC10_S1 and
R_MICROMIPS_PC16_S1 relocations originally affected, and the
R_MIPS16_PC16_S1 relocation recently added with commit c9775dde3277
("MIPS16: Add R_MIPS16_PC16_S1 branch relocation support") actually
triggering a linker error, due to its heightened processing strictness
level:

$ cat test.s
	.text
	.set	mips16
foo:
	b	bar

	.set	bar, 0x1235
	.align	4, 0
$ as -EB -n32 -o test.o test.s
$ objdump -dr test.o

test.o:     file format elf32-ntradbigmips

Disassembly of section .text:

00000000 <foo>:
   0:	f000 1000 	b	4 <foo+0x4>
			0: R_MIPS16_PC16_S1	*ABS*+0x1230
	...
$ ld -melf32btsmipn32 -Ttext 0 -e 0 -o test test.o
test.o: In function `foo':
(.text+0x0): Branch to a non-instruction-aligned address
$

This is because the ISA bit of the branch target does not match the ISA
bit of the referring branch, hardwired to 1 of course.

Retain the ISA bit then, so that the linker knows this is really MIPS16
code referred:

$ objdump -dr fixed.o

fixed.o:     file format elf32-ntradbigmips

Disassembly of section .text:

00000000 <foo>:
   0:	f000 1000 	b	4 <foo+0x4>
			0: R_MIPS16_PC16_S1	*ABS*+0x1231
	...
$ ld -melf32btsmipn32 -Ttext 0 -e 0 -o fixed fixed.o
$

Add a set of MIPS16 tests to cover the relevant cases, excluding linker
tests though which would overflow the in-place addend on REL targets and
use them as dump patterns for RELA targets only.

	gas/
	* config/tc-mips.c (md_apply_fix) <BFD_RELOC_MIPS16_16_PCREL_S1>
	<BFD_RELOC_MICROMIPS_7_PCREL_S1, BFD_RELOC_MICROMIPS_10_PCREL_S1>
	<BFD_RELOC_MICROMIPS_16_PCREL_S1>: Keep the ISA bit in the
	addend calculated.
	* testsuite/gas/mips/mips16-branch-absolute.s: Set the ISA bit
	in `bar', export `foo'.
	* testsuite/gas/mips/mips16-branch-absolute.d: Adjust
	accordingly.
	* testsuite/gas/mips/mips16-branch-absolute-n32.d: Likewise.
	* testsuite/gas/mips/mips16-branch-absolute-n64.d: Likewise.
	* testsuite/gas/mips/mips16-branch-absolute-addend-n32.d:
	Likewise.
	* testsuite/gas/mips/mips16-branch-absolute-addend-n64.d:
	Likewise.

	ld/
	* testsuite/ld-mips-elf/mips16-branch-absolute.d: New test.
	* testsuite/ld-mips-elf/mips16-branch-absolute-n32.d: New test.
	* testsuite/ld-mips-elf/mips16-branch-absolute-n64.d: New test.
	* testsuite/ld-mips-elf/mips16-branch-absolute-addend.d: New
	test.
	* testsuite/ld-mips-elf/mips16-branch-absolute-addend-n32.d: New
	test.
	* testsuite/ld-mips-elf/mips16-branch-absolute-addend-n64.d: New
	test.
	* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests, except
	from `mips16-branch-absolute' and
	`mips16-branch-absolute-addend', referred indirectly only.

8 files changed, 83 insertions, 0 deletions

diff --git a/ld/ChangeLog b/ld/ChangeLog
index 640b36f..1f8a499 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,5 +1,20 @@
 2016-07-14  Maciej W. Rozycki  <macro@imgtec.com>
 
+	* testsuite/ld-mips-elf/mips16-branch-absolute.d: New test.
+	* testsuite/ld-mips-elf/mips16-branch-absolute-n32.d: New test.
+	* testsuite/ld-mips-elf/mips16-branch-absolute-n64.d: New test.
+	* testsuite/ld-mips-elf/mips16-branch-absolute-addend.d: New
+	test.
+	* testsuite/ld-mips-elf/mips16-branch-absolute-addend-n32.d: New
+	test.
+	* testsuite/ld-mips-elf/mips16-branch-absolute-addend-n64.d: New
+	test.
+	* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests, except
+	from `mips16-branch-absolute' and
+	`mips16-branch-absolute-addend', referred indirectly only.
+
+2016-07-14  Maciej W. Rozycki  <macro@imgtec.com>
+
 	* testsuite/ld-mips-elf/branch-absolute.d: New test.
 	* testsuite/ld-mips-elf/branch-absolute-n32.d: New test.
 	* testsuite/ld-mips-elf/branch-absolute-n64.d: New test.
diff --git a/ld/testsuite/ld-mips-elf/mips-elf.exp b/ld/testsuite/ld-mips-elf/mips-elf.exp
index 21867f1..cca6695 100644
--- a/ld/testsuite/ld-mips-elf/mips-elf.exp
+++ b/ld/testsuite/ld-mips-elf/mips-elf.exp
@@ -157,6 +157,16 @@ 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)]]
+if $has_newabi {
+    run_dump_test "mips16-branch-absolute-n32" \
+					[list [list ld $abi_ldflags(n32)]]
+    run_dump_test "mips16-branch-absolute-addend-n32" \
+					[list [list ld $abi_ldflags(n32)]]
+    run_dump_test "mips16-branch-absolute-n64" \
+					[list [list ld $abi_ldflags(n64)]]
+    run_dump_test "mips16-branch-absolute-addend-n64" \
+					[list [list ld $abi_ldflags(n64)]]
+}
 
 run_dump_test "micromips-branch-absolute" [list [list ld $abi_ldflags(o32)]]
 if $has_newabi {
diff --git a/ld/testsuite/ld-mips-elf/mips16-branch-absolute-addend-n32.d b/ld/testsuite/ld-mips-elf/mips16-branch-absolute-addend-n32.d
new file mode 100644
index 0000000..69c37c1
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/mips16-branch-absolute-addend-n32.d
@@ -0,0 +1,6 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS16 link branch to absolute expression with addend (n32)
+#source: ../../../gas/testsuite/gas/mips/mips16-branch-absolute-addend.s
+#as: -EB -n32 -march=from-abi
+#ld: -EB -Ttext 0x12340000 -e foo
+#dump: mips16-branch-absolute-addend.d
diff --git a/ld/testsuite/ld-mips-elf/mips16-branch-absolute-addend-n64.d b/ld/testsuite/ld-mips-elf/mips16-branch-absolute-addend-n64.d
new file mode 100644
index 0000000..d6047b9
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/mips16-branch-absolute-addend-n64.d
@@ -0,0 +1,6 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS16 link branch to absolute expression with addend (n64)
+#source: ../../../gas/testsuite/gas/mips/mips16-branch-absolute-addend.s
+#as: -EB -64 -march=from-abi
+#ld: -EB -Ttext 0x12340000 -e foo
+#dump: mips16-branch-absolute-addend.d
diff --git a/ld/testsuite/ld-mips-elf/mips16-branch-absolute-addend.d b/ld/testsuite/ld-mips-elf/mips16-branch-absolute-addend.d
new file mode 100644
index 0000000..2427b9a
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/mips16-branch-absolute-addend.d
@@ -0,0 +1,17 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS16 link branch to absolute expression with addend
+#source: ../../../gas/testsuite/gas/mips/mips16-branch-absolute-addend.s
+#as: -EB -32
+#ld: -EB -Ttext 0x12340000 -e foo
+
+.*: +file format .*mips.*
+
+Disassembly of section \.text:
+	\.\.\.
+[0-9a-f]+ <[^>]*> f445 1014 	b	0*123468ac <bar\+0x1233>
+[0-9a-f]+ <[^>]*> f445 6012 	bteqz	0*123468ac <bar\+0x1233>
+[0-9a-f]+ <[^>]*> f445 6110 	btnez	0*123468ac <bar\+0x1233>
+[0-9a-f]+ <[^>]*> f445 220e 	beqz	v0,0*123468ac <bar\+0x1233>
+[0-9a-f]+ <[^>]*> f445 2a0c 	bnez	v0,0*123468ac <bar\+0x1233>
+[0-9a-f]+ <[^>]*> 6500      	nop
+	\.\.\.
diff --git a/ld/testsuite/ld-mips-elf/mips16-branch-absolute-n32.d b/ld/testsuite/ld-mips-elf/mips16-branch-absolute-n32.d
new file mode 100644
index 0000000..7bff198
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/mips16-branch-absolute-n32.d
@@ -0,0 +1,6 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS16 link branch to absolute expression (n32)
+#source: ../../../gas/testsuite/gas/mips/mips16-branch-absolute.s
+#as: -EB -n32 -march=from-abi
+#ld: -EB -Ttext 0 -e foo
+#dump: mips16-branch-absolute.d
diff --git a/ld/testsuite/ld-mips-elf/mips16-branch-absolute-n64.d b/ld/testsuite/ld-mips-elf/mips16-branch-absolute-n64.d
new file mode 100644
index 0000000..6edb58d
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/mips16-branch-absolute-n64.d
@@ -0,0 +1,6 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS16 link branch to absolute expression (n64)
+#source: ../../../gas/testsuite/gas/mips/mips16-branch-absolute.s
+#as: -EB -64 -march=from-abi
+#ld: -EB -Ttext 0 -e foo
+#dump: mips16-branch-absolute.d
diff --git a/ld/testsuite/ld-mips-elf/mips16-branch-absolute.d b/ld/testsuite/ld-mips-elf/mips16-branch-absolute.d
new file mode 100644
index 0000000..eac08fa
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/mips16-branch-absolute.d
@@ -0,0 +1,17 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS16 link branch to absolute expression
+#source: ../../../gas/testsuite/gas/mips/mips16-branch-absolute.s
+#as: -EB -32
+#ld: -EB -Ttext 0 -e foo
+
+.*: +file format .*mips.*
+
+Disassembly of section \.text:
+	\.\.\.
+[0-9a-f]+ <[^>]*> f100 1018 	b	0+001234 <foo\+0x234>
+[0-9a-f]+ <[^>]*> f100 6016 	bteqz	0+001234 <foo\+0x234>
+[0-9a-f]+ <[^>]*> f100 6114 	btnez	0+001234 <foo\+0x234>
+[0-9a-f]+ <[^>]*> f100 2212 	beqz	v0,0+001234 <foo\+0x234>
+[0-9a-f]+ <[^>]*> f100 2a10 	bnez	v0,0+001234 <foo\+0x234>
+[0-9a-f]+ <[^>]*> 6500      	nop
+	\.\.\.