[binutils-gdb] x86: swap operands in OUT-with-immediate template
Jan Beulich
jbeulich@sourceware.org
Fri Jun 13 11:46:33 GMT 2025
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=620dc0f52376d4d3a24c608c297205e1f56cb0e2
commit 620dc0f52376d4d3a24c608c297205e1f56cb0e2
Author: Jan Beulich <jbeulich@suse.com>
Date: Fri Jun 13 13:46:06 2025 +0200
x86: swap operands in OUT-with-immediate template
In a number of places we assume that immediates come first in the set of
operands. It is mere luck that so far OUT, having operands the other way
around, wasn't negatively impacted by this.
Leverage this to have a few loops start from the first non-immediate
operand (or in one case to stop there). Note, however, that
process_immext() inserts an immediate last, so especially all output_*()
functions cannot be changed in the same way.
Diff:
---
gas/config/tc-i386.c | 66 ++++++++++++++++++++++++++--------------------------
opcodes/i386-opc.tbl | 4 +++-
opcodes/i386-tbl.h | 4 ++--
3 files changed, 38 insertions(+), 36 deletions(-)
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index ca68881b4a0..43211b0a644 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -2589,22 +2589,23 @@ operand_size_match (const insn_template *t)
&& t->opcode_modifier.jump != JUMP_ABSOLUTE)
return match;
+ for (j = 0; j < i.imm_operands; j++)
+ /* Instruction templates with only sign-extended 8-bit immediate
+ operand also have a second template with full-operand-size
+ immediate operand under a different opcode. Don't match the
+ first template if sign-extended 8-bit immediate operand should
+ be excluded. */
+ if (pp.no_imm8s
+ && !t->operand_types[j].bitfield.imm8
+ && t->operand_types[j].bitfield.imm8s)
+ {
+ gas_assert (!t->opcode_modifier.d);
+ return 0;
+ }
+
/* Check memory and accumulator operand size. */
- for (j = 0; j < i.operands; j++)
+ for (; j < i.operands; j++)
{
- /* Instruction templates with only sign-extended 8-bit immediate
- operand also have a second template with full-operand-size
- immediate operand under a different opcode. Don't match the
- first template if sign-extended 8-bit immediate operand should
- be excluded. */
- if (pp.no_imm8s
- && !t->operand_types[j].bitfield.imm8
- && t->operand_types[j].bitfield.imm8s)
- {
- match = 0;
- break;
- }
-
if (i.types[j].bitfield.class == Reg
&& (t->operand_types[j].bitfield.class == Reg
|| (t->operand_types[j].bitfield.instance == Accum
@@ -2655,7 +2656,7 @@ operand_size_match (const insn_template *t)
/* Check reverse. */
gas_assert (i.operands >= 2);
- for (j = 0; j < i.operands; j++)
+ for (j = i.imm_operands; j < i.operands; j++)
{
unsigned int given = i.operands - j - 1;
@@ -7129,12 +7130,14 @@ i386_assemble (char *line)
swap_operands ();
/* The order of the immediates should be reversed for 2-immediates EXTRQ
- and INSERTQ instructions. Also UWRMSR wants its immediate to be in the
- "canonical" place (first), despite it appearing last (in AT&T syntax, or
- because of the swapping above) in the incoming set of operands. */
+ and INSERTQ instructions. Also OUT, UWRMSR, and WRMSRNS want their
+ immediate to be in the "canonical" place (first), despite it appearing
+ last (in AT&T syntax, or because of the swapping above) in the incoming
+ set of operands. */
if ((i.imm_operands == 2
&& (t->mnem_off == MN_extrq || t->mnem_off == MN_insertq))
- || ((t->mnem_off == MN_uwrmsr || t->mnem_off == MN_wrmsrns)
+ || ((t->mnem_off == MN_out || t->mnem_off == MN_uwrmsr
+ || t->mnem_off == MN_wrmsrns)
&& i.imm_operands && i.operands > i.imm_operands))
swap_2_operands (0, 1);
@@ -7149,11 +7152,8 @@ i386_assemble (char *line)
|| t->mnem_off == MN_rdmsr
|| t->mnem_off == MN_wrmsrns)
{
- for (j = 0; j < i.operands; j++)
- {
- if (operand_type_check(i.types[j], imm))
- i.types[j] = smallest_imm_type (i.op[j].imms->X_add_number);
- }
+ for (j = 0; j < i.imm_operands; j++)
+ i.types[j] = smallest_imm_type (i.op[j].imms->X_add_number);
}
else
optimize_imm ();
@@ -8467,7 +8467,7 @@ optimize_disp (const insn_template *t)
&& (!t->opcode_modifier.jump
|| i.jumpabsolute || i.types[0].bitfield.baseindex))
{
- for (op = 0; op < i.operands; ++op)
+ for (op = i.imm_operands; op < i.operands; ++op)
{
const expressionS *exp = i.op[op].disps;
@@ -8808,7 +8808,7 @@ check_VecOperands (const insn_template *t)
unsigned int j;
type.bitfield.baseindex = 1;
- for (j = 0; j < i.operands; ++j)
+ for (j = i.imm_operands; j < i.operands; ++j)
{
if (j != op
&& !operand_type_register_match(i.types[j],
@@ -8824,7 +8824,7 @@ check_VecOperands (const insn_template *t)
else if (t->opcode_modifier.broadcast && i.mem_operands)
{
/* Find memory operand. */
- for (op = 0; op < i.operands; op++)
+ for (op = i.imm_operands; op < i.operands; op++)
if (i.flags[op] & Operand_Mem)
break;
gas_assert (op < i.operands);
@@ -8933,7 +8933,7 @@ check_VecOperands (const insn_template *t)
const i386_operand_type *type = NULL, *fallback = NULL;
i.memshift = 0;
- for (op = 0; op < i.operands; op++)
+ for (op = i.imm_operands; op < i.operands; op++)
if (i.flags[op] & Operand_Mem)
{
if (t->opcode_modifier.evex == EVEXLIG)
@@ -8975,7 +8975,7 @@ check_VecOperands (const insn_template *t)
i.memshift = -1;
}
- for (op = 0; op < i.operands; op++)
+ for (op = i.imm_operands; op < i.operands; op++)
if (operand_type_check (i.types[op], disp)
&& i.op[op].disps->X_op == O_constant)
{
@@ -9069,7 +9069,7 @@ check_EgprOperands (const insn_template *t)
if (!t->opcode_modifier.noegpr)
return false;
- for (unsigned int op = 0; op < i.operands; op++)
+ for (unsigned int op = i.imm_operands; op < i.operands; op++)
{
if (i.types[op].bitfield.class != Reg)
continue;
@@ -9131,7 +9131,7 @@ check_APX_operands (const insn_template *t)
static bool
check_Rex_required (void)
{
- for (unsigned int op = 0; op < i.operands; op++)
+ for (unsigned int op = i.imm_operands; op < i.operands; op++)
{
if (i.types[op].bitfield.class != Reg)
continue;
@@ -10444,7 +10444,7 @@ process_suffix (const insn_template *t)
else
need = flag_code == CODE_64BIT ? need_qword : need_word;
- for (op = 0; op < i.operands; op++)
+ for (op = i.imm_operands; op < i.operands; op++)
{
if (i.types[op].bitfield.class != Reg)
continue;
@@ -10776,7 +10776,7 @@ process_operands (void)
unnecessary segment overrides. */
const reg_entry *default_seg = NULL;
- for (unsigned int j = 0; j < i.operands; j++)
+ for (unsigned int j = i.imm_operands; j < i.operands; j++)
if (i.types[j].bitfield.instance != InstanceNone)
i.reg_operands--;
diff --git a/opcodes/i386-opc.tbl b/opcodes/i386-opc.tbl
index 348b0e94129..6eadc2ebf73 100644
--- a/opcodes/i386-opc.tbl
+++ b/opcodes/i386-opc.tbl
@@ -275,7 +275,9 @@ in, 0xe4, 0, W|No_sSuf|No_qSuf, { Imm8, Acc|Byte|Word|Dword }
in, 0xec, 0, W|No_sSuf|No_qSuf, { InOutPortReg, Acc|Byte|Word|Dword }
in, 0xe4, 0, W|No_sSuf|No_qSuf|IntelSuffix, { Imm8 }
in, 0xec, 0, W|No_sSuf|No_qSuf|IntelSuffix, { InOutPortReg }
-out, 0xe6, 0, W|No_sSuf|No_qSuf, { Acc|Byte|Word|Dword, Imm8 }
+// Immediates want to be first; md_assemble() takes care of swapping operands
+// accordingly.
+out, 0xe6, 0, W|No_sSuf|No_qSuf, { Imm8, Acc|Byte|Word|Dword }
out, 0xee, 0, W|No_sSuf|No_qSuf, { Acc|Byte|Word|Dword, InOutPortReg }
out, 0xe6, 0, W|No_sSuf|No_qSuf|IntelSuffix, { Imm8 }
out, 0xee, 0, W|No_sSuf|No_qSuf|IntelSuffix, { InOutPortReg }
diff --git a/opcodes/i386-tbl.h b/opcodes/i386-tbl.h
index 1711a7bc54a..8c5b04f2dd7 100644
--- a/opcodes/i386-tbl.h
+++ b/opcodes/i386-tbl.h
@@ -544,9 +544,9 @@ static const insn_template i386_optab[] =
0, 0 },
{ { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } },
{ { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } },
- { { { 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0,
+ { { { 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0 } },
- { { 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ { { 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0,
0, 0, 0, 0, 0, 0 } } } },
{ MN_out, 0xee, 2, SPACE_BASE, None,
{ 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0,
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