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, 65 insertions, 55 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 2e5015a..13243ce 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,5 +1,22 @@
 2016-07-14  Maciej W. Rozycki  <macro@imgtec.com>
 
+	* 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.
+
+2016-07-14  Maciej W. Rozycki  <macro@imgtec.com>
+
 	* testsuite/gas/mips/mips16-branch-absolute.d: Update patterns.
 	* testsuite/gas/mips/branch-absolute.d: New test.
 	* testsuite/gas/mips/branch-absolute-n32.d: New test.
diff --git a/gas/config/tc-mips.c b/gas/config/tc-mips.c
index b7997c7..6c0be63 100644
--- a/gas/config/tc-mips.c
+++ b/gas/config/tc-mips.c
@@ -15188,15 +15188,7 @@ md_apply_fix (fixS *fixP, valueT *valP, segT seg ATTRIBUTE_UNUSED)
     case BFD_RELOC_MICROMIPS_7_PCREL_S1:
     case BFD_RELOC_MICROMIPS_10_PCREL_S1:
     case BFD_RELOC_MICROMIPS_16_PCREL_S1:
-      /* We adjust the offset back to even.  */
-      if ((*valP & 0x1) != 0)
-	--(*valP);
-
-      if (! fixP->fx_done)
-	break;
-
-      /* Should never visit here, because we keep the relocation.  */
-      abort ();
+      gas_assert (!fixP->fx_done);
       break;
 
     case BFD_RELOC_VTABLE_INHERIT:
diff --git a/gas/testsuite/gas/mips/mips16-branch-absolute-addend-n32.d b/gas/testsuite/gas/mips/mips16-branch-absolute-addend-n32.d
index 48aca38..d506d49 100644
--- a/gas/testsuite/gas/mips/mips16-branch-absolute-addend-n32.d
+++ b/gas/testsuite/gas/mips/mips16-branch-absolute-addend-n32.d
@@ -8,14 +8,14 @@
 Disassembly of section \.text:
 	\.\.\.
 [0-9a-f]+ <[^>]*> f000 1000 	b	00001004 <foo\+0x4>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a8
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a9
 [0-9a-f]+ <[^>]*> f000 6000 	bteqz	00001008 <foo\+0x8>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a8
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a9
 [0-9a-f]+ <[^>]*> f000 6100 	btnez	0000100c <foo\+0xc>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a8
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a9
 [0-9a-f]+ <[^>]*> f000 2200 	beqz	v0,00001010 <foo\+0x10>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a8
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a9
 [0-9a-f]+ <[^>]*> f000 2a00 	bnez	v0,00001014 <foo\+0x14>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a8
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a9
 [0-9a-f]+ <[^>]*> 6500      	nop
 	\.\.\.
diff --git a/gas/testsuite/gas/mips/mips16-branch-absolute-addend-n64.d b/gas/testsuite/gas/mips/mips16-branch-absolute-addend-n64.d
index f5770a9..baa0700 100644
--- a/gas/testsuite/gas/mips/mips16-branch-absolute-addend-n64.d
+++ b/gas/testsuite/gas/mips/mips16-branch-absolute-addend-n64.d
@@ -8,24 +8,24 @@
 Disassembly of section \.text:
 	\.\.\.
 [0-9a-f]+ <[^>]*> f000 1000 	b	0000000000001004 <foo\+0x4>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a8
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a8
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a8
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a9
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a9
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a9
 [0-9a-f]+ <[^>]*> f000 6000 	bteqz	0000000000001008 <foo\+0x8>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a8
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a8
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a8
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a9
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a9
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a9
 [0-9a-f]+ <[^>]*> f000 6100 	btnez	000000000000100c <foo\+0xc>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a8
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a8
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a8
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a9
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a9
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a9
 [0-9a-f]+ <[^>]*> f000 2200 	beqz	v0,0000000000001010 <foo\+0x10>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a8
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a8
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a8
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a9
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a9
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a9
 [0-9a-f]+ <[^>]*> f000 2a00 	bnez	v0,0000000000001014 <foo\+0x14>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a8
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a8
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a8
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x123468a9
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a9
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x123468a9
 [0-9a-f]+ <[^>]*> 6500      	nop
 	\.\.\.
diff --git a/gas/testsuite/gas/mips/mips16-branch-absolute-n32.d b/gas/testsuite/gas/mips/mips16-branch-absolute-n32.d
index 444edeb..fb7860c 100644
--- a/gas/testsuite/gas/mips/mips16-branch-absolute-n32.d
+++ b/gas/testsuite/gas/mips/mips16-branch-absolute-n32.d
@@ -8,14 +8,14 @@
 Disassembly of section \.text:
 	\.\.\.
 [0-9a-f]+ <[^>]*> f000 1000 	b	00001004 <foo\+0x4>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1230
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1231
 [0-9a-f]+ <[^>]*> f000 6000 	bteqz	00001008 <foo\+0x8>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1230
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1231
 [0-9a-f]+ <[^>]*> f000 6100 	btnez	0000100c <foo\+0xc>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1230
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1231
 [0-9a-f]+ <[^>]*> f000 2200 	beqz	v0,00001010 <foo\+0x10>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1230
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1231
 [0-9a-f]+ <[^>]*> f000 2a00 	bnez	v0,00001014 <foo\+0x14>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1230
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1231
 [0-9a-f]+ <[^>]*> 6500      	nop
 	\.\.\.
diff --git a/gas/testsuite/gas/mips/mips16-branch-absolute-n64.d b/gas/testsuite/gas/mips/mips16-branch-absolute-n64.d
index eebd5dd..3aa7d9e 100644
--- a/gas/testsuite/gas/mips/mips16-branch-absolute-n64.d
+++ b/gas/testsuite/gas/mips/mips16-branch-absolute-n64.d
@@ -8,24 +8,24 @@
 Disassembly of section \.text:
 	\.\.\.
 [0-9a-f]+ <[^>]*> f000 1000 	b	0000000000001004 <foo\+0x4>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1230
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1230
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1230
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1231
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1231
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1231
 [0-9a-f]+ <[^>]*> f000 6000 	bteqz	0000000000001008 <foo\+0x8>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1230
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1230
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1230
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1231
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1231
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1231
 [0-9a-f]+ <[^>]*> f000 6100 	btnez	000000000000100c <foo\+0xc>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1230
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1230
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1230
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1231
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1231
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1231
 [0-9a-f]+ <[^>]*> f000 2200 	beqz	v0,0000000000001010 <foo\+0x10>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1230
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1230
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1230
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1231
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1231
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1231
 [0-9a-f]+ <[^>]*> f000 2a00 	bnez	v0,0000000000001014 <foo\+0x14>
-[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1230
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1230
-[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1230
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*\+0x1231
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1231
+[ 	]*[0-9a-f]+: R_MIPS_NONE	\*ABS\*\+0x1231
 [0-9a-f]+ <[^>]*> 6500      	nop
 	\.\.\.
diff --git a/gas/testsuite/gas/mips/mips16-branch-absolute.d b/gas/testsuite/gas/mips/mips16-branch-absolute.d
index 35788bf..4d2c9d3 100644
--- a/gas/testsuite/gas/mips/mips16-branch-absolute.d
+++ b/gas/testsuite/gas/mips/mips16-branch-absolute.d
@@ -6,15 +6,15 @@
 
 Disassembly of section \.text:
 	\.\.\.
-[0-9a-f]+ <[^>]*> f101 1018 	b	00002234 <bar\+0x1000>
+[0-9a-f]+ <[^>]*> f101 1018 	b	00002234 <bar\+0xfff>
 [ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*
-[0-9a-f]+ <[^>]*> f101 6018 	bteqz	00002238 <bar\+0x1004>
+[0-9a-f]+ <[^>]*> f101 6018 	bteqz	00002238 <bar\+0x1003>
 [ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*
-[0-9a-f]+ <[^>]*> f101 6118 	btnez	0000223c <bar\+0x1008>
+[0-9a-f]+ <[^>]*> f101 6118 	btnez	0000223c <bar\+0x1007>
 [ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*
-[0-9a-f]+ <[^>]*> f101 2218 	beqz	v0,00002240 <bar\+0x100c>
+[0-9a-f]+ <[^>]*> f101 2218 	beqz	v0,00002240 <bar\+0x100b>
 [ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*
-[0-9a-f]+ <[^>]*> f101 2a18 	bnez	v0,00002244 <bar\+0x1010>
+[0-9a-f]+ <[^>]*> f101 2a18 	bnez	v0,00002244 <bar\+0x100f>
 [ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	\*ABS\*
 [0-9a-f]+ <[^>]*> 6500      	nop
 	\.\.\.
diff --git a/gas/testsuite/gas/mips/mips16-branch-absolute.s b/gas/testsuite/gas/mips/mips16-branch-absolute.s
index 948b0b6..23203a4 100644
--- a/gas/testsuite/gas/mips/mips16-branch-absolute.s
+++ b/gas/testsuite/gas/mips/mips16-branch-absolute.s
@@ -2,6 +2,7 @@
 
 	.space	0x1000
 
+	.globl	foo
 	.ent	foo
 	.set	mips16
 foo:
@@ -18,4 +19,4 @@ foo:
 	.align	4, 0
 	.space	16
 
-	.set	bar, 0x1234
+	.set	bar, 0x1235