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[binutils-gdb] x86: relax redundant REX prefix check
- From: Jan Beulich <jbeulich at sourceware dot org>
- To: bfd-cvs at sourceware dot org
- Date: 1 Jun 2018 06:41:53 -0000
- Subject: [binutils-gdb] x86: relax redundant REX prefix check
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=44846f29ab3a5fdab229cb63d9cd42323ed85767
commit 44846f29ab3a5fdab229cb63d9cd42323ed85767
Author: Jan Beulich <jbeulich@novell.com>
Date: Fri Jun 1 08:39:54 2018 +0200
x86: relax redundant REX prefix check
All REX bits can be specified via individual prefixes. Redundancy should
only be reported on a per-bit basis.
Note that I originally had further checks added to the test case,
checking the effect also on PDEP. I had to strip those, because my patch
to correctly handle those
(https://sourceware.org/ml/binutils/2017-02/msg00280.html) was rejected.
I continue to think that there should not be any new prefix introduced
to handle the VEX case - whether the encoding of an insn requires VEX et
al should not be of immediate interest to the programmer.
Diff:
---
gas/ChangeLog | 8 ++++++++
gas/config/tc-i386.c | 5 +++--
gas/testsuite/gas/i386/ilp32/rex.d | 8 ++++++++
gas/testsuite/gas/i386/rex.d | 8 ++++++++
gas/testsuite/gas/i386/rex.s | 10 ++++++++++
5 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/gas/ChangeLog b/gas/ChangeLog
index fdf8b2b..67da990 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,5 +1,13 @@
2018-06-01 Jan Beulich <jbeulich@suse.com>
+ * config/tc-i386.c (add_prefix): Check REX bits individually.
+ * testsuite/gas/i386/rex.s: Add tests for overriding individual
+ REX bits, including when others are already set.
+ * testsuite/gas/i386/ilp32/rex.d, testsuite/gas/i386/rex.d:
+ Adjust expectations.
+
+2018-06-01 Jan Beulich <jbeulich@suse.com>
+
* config/tc-i386.c (control): Delete.
(parse_real_register): Simply check "control" bit. Re-wrap.
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 07a4e11..2d20f1c 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -2330,8 +2330,9 @@ add_prefix (unsigned int prefix)
&& flag_code == CODE_64BIT)
{
if ((i.prefix[REX_PREFIX] & prefix & REX_W)
- || ((i.prefix[REX_PREFIX] & (REX_R | REX_X | REX_B))
- && (prefix & (REX_R | REX_X | REX_B))))
+ || (i.prefix[REX_PREFIX] & prefix & REX_R)
+ || (i.prefix[REX_PREFIX] & prefix & REX_X)
+ || (i.prefix[REX_PREFIX] & prefix & REX_B))
ret = PREFIX_EXIST;
q = REX_PREFIX;
}
diff --git a/gas/testsuite/gas/i386/ilp32/rex.d b/gas/testsuite/gas/i386/ilp32/rex.d
index 36241c1..0646ab4 100644
--- a/gas/testsuite/gas/i386/ilp32/rex.d
+++ b/gas/testsuite/gas/i386/ilp32/rex.d
@@ -16,6 +16,14 @@ Disassembly of section .text:
[ ]*[0-9a-f]+:[ ]+4a 0f ae 04 05 00 00 00 00[ ]+fxsave64[ ]+(0x0)?\(,%r8(,1)?\)
[ ]*[0-9a-f]+:[ ]+43 0f ae 04 00[ ]+fxsave[ ]+\(%r8,%r8(,1)?\)
[ ]*[0-9a-f]+:[ ]+4b 0f ae 04 00[ ]+fxsave64[ ]+\(%r8,%r8(,1)?\)
+[ ]*[0-9a-f]+:[ ]+48 03 04 00[ ]+add[ ]+\(%rax,%rax(,1)?\),%rax
+[ ]*[0-9a-f]+:[ ]+44 03 04 00[ ]+add[ ]+\(%rax,%rax(,1)?\),%r8d
+[ ]*[0-9a-f]+:[ ]+41 03 04 00[ ]+add[ ]+\(%r8,%rax(,1)?\),%eax
+[ ]*[0-9a-f]+:[ ]+42 03 04 00[ ]+add[ ]+\(%rax,%r8(,1)?\),%eax
+[ ]*[0-9a-f]+:[ ]+49 03 04 00[ ]+add[ ]+\(%r8,%rax(,1)?\),%rax
+[ ]*[0-9a-f]+:[ ]+46 03 04 00[ ]+add[ ]+\(%rax,%r8(,1)?\),%r8d
+[ ]*[0-9a-f]+:[ ]+45 03 04 00[ ]+add[ ]+\(%r8,%rax(,1)?\),%r8d
+[ ]*[0-9a-f]+:[ ]+4a 03 04 00[ ]+add[ ]+\(%rax,%r8(,1)?\),%rax
[ ]*[0-9a-f]+:[ ]+41\s+rex\.B
[ ]*[0-9a-f]+:[ ]+9b dd 30\s+fsave\s+\(%rax\)
[ ]*[0-9a-f]+:[ ]+9b 41 dd 30\s+fsave\s+\(%r8\)
diff --git a/gas/testsuite/gas/i386/rex.d b/gas/testsuite/gas/i386/rex.d
index 3c52e16..5af478f 100644
--- a/gas/testsuite/gas/i386/rex.d
+++ b/gas/testsuite/gas/i386/rex.d
@@ -15,6 +15,14 @@ Disassembly of section .text:
[ ]*[0-9a-f]+:[ ]+4a 0f ae 04 05 00 00 00 00[ ]+fxsave64[ ]+(0x0)?\(,%r8(,1)?\)
[ ]*[0-9a-f]+:[ ]+43 0f ae 04 00[ ]+fxsave[ ]+\(%r8,%r8(,1)?\)
[ ]*[0-9a-f]+:[ ]+4b 0f ae 04 00[ ]+fxsave64[ ]+\(%r8,%r8(,1)?\)
+[ ]*[0-9a-f]+:[ ]+48 03 04 00[ ]+add[ ]+\(%rax,%rax(,1)?\),%rax
+[ ]*[0-9a-f]+:[ ]+44 03 04 00[ ]+add[ ]+\(%rax,%rax(,1)?\),%r8d
+[ ]*[0-9a-f]+:[ ]+41 03 04 00[ ]+add[ ]+\(%r8,%rax(,1)?\),%eax
+[ ]*[0-9a-f]+:[ ]+42 03 04 00[ ]+add[ ]+\(%rax,%r8(,1)?\),%eax
+[ ]*[0-9a-f]+:[ ]+49 03 04 00[ ]+add[ ]+\(%r8,%rax(,1)?\),%rax
+[ ]*[0-9a-f]+:[ ]+46 03 04 00[ ]+add[ ]+\(%rax,%r8(,1)?\),%r8d
+[ ]*[0-9a-f]+:[ ]+45 03 04 00[ ]+add[ ]+\(%r8,%rax(,1)?\),%r8d
+[ ]*[0-9a-f]+:[ ]+4a 03 04 00[ ]+add[ ]+\(%rax,%r8(,1)?\),%rax
[ ]*[0-9a-f]+:[ ]+41\s+rex\.B
[ ]*[0-9a-f]+:[ ]+9b dd 30\s+fsave\s+\(%rax\)
[ ]*[0-9a-f]+:[ ]+9b 41 dd 30\s+fsave\s+\(%r8\)
diff --git a/gas/testsuite/gas/i386/rex.s b/gas/testsuite/gas/i386/rex.s
index 004b9b8..c1490cc 100644
--- a/gas/testsuite/gas/i386/rex.s
+++ b/gas/testsuite/gas/i386/rex.s
@@ -10,6 +10,16 @@ _start:
rex/fxsave (%r8,%r8)
rex64/fxsave (%r8,%r8)
+ rex.w add (%rax,%rax), %eax
+ rex.r add (%rax,%rax), %eax
+ rex.b add (%rax,%rax), %eax
+ rex.x add (%rax,%rax), %eax
+
+ rex.w add (%r8,%rax), %eax
+ rex.r add (%rax,%r8), %eax
+ rex.b add (%rax,%rax), %r8d
+ rex.x add (%rax,%rax), %rax
+
.byte 0x41,0x9b,0xdd,0x30
fsave (%r8)