[PATCH] ix86: wrap constants
Jan Beulich
jbeulich@suse.com
Fri Jun 4 12:14:35 GMT 2021
Non-64-bit code should get handled the same with or without BFD64. This
wasn't the case though in a number of situations (and quite likely there
are more that I haven't spotted yet).
It's not very nice to tie the check in md_apply_fix() to object_64bit,
but afaict at that time we have no record anymore of the mode an insn
was assembled in (it might also have been data). This doesn't look to be
the first inconsistency of this kind, though. In x86_cons() it's even
less clear what the right approach would be: flag_code shouldn't matter
for data emission, but instead we'd need to know from which mode(s) the
data actually gets accessed. On this basis, signed_cons() also gets
adjusted.
gas/
2021-06-XX Jan Beulich <jbeulich@suse.com>
* config/tc-i386.c (extend_to_address): New.
(x86_cons, i386_finalize_immediate, md_apply_fix): Use it.
(signed_cons): Use object_64bit.
* testsuite/gas/i386/wrap32.s, testsuite/gas/i386/wrap32-data.d,
testsuite/gas/i386/wrap32-text.d: New.
* testsuite/gas/i386/i386.exp: Run new tests.
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -2457,6 +2457,19 @@ fits_in_unsigned_long (addressT num ATTR
#endif
} /* fits_in_unsigned_long() */
+static INLINE valueT extend_to_address (addressT num)
+{
+#ifdef BFD64
+ if (fits_in_unsigned_long(num))
+ return (num ^ ((addressT) 1 << 31)) - ((addressT) 1 << 31);
+
+ if (!fits_in_signed_long (num))
+ return num & 0xffffffff;
+#endif
+
+ return num;
+}
+
static INLINE int
fits_in_disp8 (offsetT num)
{
@@ -10457,13 +10470,17 @@ x86_cons (expressionS *exp, int size)
if (intel_syntax)
i386_intel_simplify (exp);
+ /* If not 64bit, massage value, to account for wraparound when !BFD64. */
+ if (size == 4 && exp->X_op == O_constant && !object_64bit)
+ exp->X_add_number = extend_to_address (exp->X_add_number);
+
return got_reloc;
}
static void
signed_cons (int size)
{
- if (flag_code == CODE_64BIT)
+ if (object_64bit)
cons_sign = 1;
cons (size);
cons_sign = -1;
@@ -10718,11 +10735,11 @@ i386_finalize_immediate (segT exp_seg AT
{
/* Size it properly later. */
i.types[this_operand].bitfield.imm64 = 1;
- /* If not 64bit, sign extend val. */
- if (flag_code != CODE_64BIT
- && (exp->X_add_number & ~(((addressT) 2 << 31) - 1)) == 0)
- exp->X_add_number
- = (exp->X_add_number ^ ((addressT) 1 << 31)) - ((addressT) 1 << 31);
+
+ /* If not 64bit, sign/zero extend val, to account for wraparound
+ when !BFD64. */
+ if (flag_code != CODE_64BIT)
+ exp->X_add_number = extend_to_address (exp->X_add_number);
}
#if (defined (OBJ_AOUT) || defined (OBJ_MAYBE_AOUT))
else if (OUTPUT_FLAVOR == bfd_target_aout_flavour
@@ -12640,6 +12657,11 @@ md_apply_fix (fixS *fixP, valueT *valP,
break;
}
#endif /* defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF) */
+
+ /* If not 64bit, massage value, to account for wraparound when !BFD64. */
+ if (!object_64bit)
+ value = extend_to_address (value);
+
*valP = value;
#endif /* !defined (TE_Mach) */
--- a/gas/testsuite/gas/i386/i386.exp
+++ b/gas/testsuite/gas/i386/i386.exp
@@ -148,6 +148,8 @@ if [gas_32_check] then {
run_dump_test "addr32"
run_dump_test "code16"
run_list_test "oversized16" "-al"
+ run_dump_test "wrap32-text"
+ run_dump_test "wrap32-data"
run_dump_test "sse4_1"
run_dump_test "sse4_1-intel"
run_dump_test "sse4_2"
--- /dev/null
+++ b/gas/testsuite/gas/i386/wrap32-data.d
@@ -0,0 +1,23 @@
+#name: i386 32-bit wrapping calculations (data/ELF)
+#source: wrap32.s
+#objdump: -rsj .data
+
+.*: +file format .*
+
+RELOCATION RECORDS FOR \[\.data\]:
+
+OFFSET +TYPE +VALUE *
+0*10 (R_386_32|dir32) *sym
+0*14 (R_386_32|dir32) *sym
+0*18 (R_386_32|dir32) *sym
+0*1c (R_386_32|dir32) *sym
+0*30 (R_386_32|dir32) *sym
+0*34 (R_386_32|dir32) *sym
+0*38 (R_386_32|dir32) *sym
+0*3c (R_386_32|dir32) *sym
+
+Contents of section .data:
+ 0+00 f4 ?00 ?00 ?00 f4 ?00 ?00 ?00 90 ?00 ?00 ?00 90 ?00 ?00 ?00 .*
+ 0+10 00 ?ff ?ff ?ff 00 ?ff ?ff ?ff f4 ?00 ?00 ?00 f4 ?00 ?00 ?00 .*
+ 0+20 f4 ?02 ?00 ?70 f4 ?00 ?00 ?80 90 ?02 ?00 ?70 90 ?00 ?00 ?80 .*
+ 0+30 00 ?01 ?00 ?70 00 ?ff ?ff ?7f f4 ?02 ?00 ?70 f4 ?00 ?00 ?80 .*
--- /dev/null
+++ b/gas/testsuite/gas/i386/wrap32-text.d
@@ -0,0 +1,43 @@
+#name: i386 32-bit wrapping calculations (text)
+#source: wrap32.s
+#objdump: -dwr
+
+.*: +file format .*
+
+Disassembly of section .text:
+
+0+ <wrap>:
+[ ]*[0-9a-f]+:[ ]+b8 f4 00 00 00 mov \$0xf4,%eax
+[ ]*[0-9a-f]+:[ ]+ba f4 00 00 00 mov \$0xf4,%edx
+[ ]*[0-9a-f]+:[ ]+b8 90 00 00 00 mov \$0x90,%eax
+[ ]*[0-9a-f]+:[ ]+ba 90 00 00 00 mov \$0x90,%edx
+[ ]*[0-9a-f]+:[ ]+b8 00 ff ff ff mov \$0xffffff00,%eax[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+ba 00 ff ff ff mov \$0xffffff00,%edx[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+b8 f4 00 00 00 mov \$0xf4,%eax[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+ba f4 00 00 00 mov \$0xf4,%edx[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+c7 00 f4 00 00 00 movl \$0xf4,\(%eax\)
+[ ]*[0-9a-f]+:[ ]+c7 02 f4 00 00 00 movl \$0xf4,\(%edx\)
+[ ]*[0-9a-f]+:[ ]+c7 00 90 00 00 00 movl \$0x90,\(%eax\)
+[ ]*[0-9a-f]+:[ ]+c7 02 90 00 00 00 movl \$0x90,\(%edx\)
+[ ]*[0-9a-f]+:[ ]+c7 00 00 ff ff ff movl \$0xffffff00,\(%eax\)[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+c7 02 00 ff ff ff movl \$0xffffff00,\(%edx\)[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+c7 00 f4 00 00 00 movl \$0xf4,\(%eax\)[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+c7 02 f4 00 00 00 movl \$0xf4,\(%edx\)[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+81 c1 f4 00 00 00 add \$0xf4,%ecx
+[ ]*[0-9a-f]+:[ ]+81 c2 f4 00 00 00 add \$0xf4,%edx
+[ ]*[0-9a-f]+:[ ]+81 c1 90 00 00 00 add \$0x90,%ecx
+[ ]*[0-9a-f]+:[ ]+81 c2 90 00 00 00 add \$0x90,%edx
+[ ]*[0-9a-f]+:[ ]+81 c1 00 ff ff ff add \$0xffffff00,%ecx[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+81 c2 00 ff ff ff add \$0xffffff00,%edx[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+81 c1 f4 00 00 00 add \$0xf4,%ecx[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+81 c2 f4 00 00 00 add \$0xf4,%edx[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+81 00 f4 00 00 00 addl \$0xf4,\(%eax\)
+[ ]*[0-9a-f]+:[ ]+81 02 f4 00 00 00 addl \$0xf4,\(%edx\)
+[ ]*[0-9a-f]+:[ ]+81 00 90 00 00 00 addl \$0x90,\(%eax\)
+[ ]*[0-9a-f]+:[ ]+81 02 90 00 00 00 addl \$0x90,\(%edx\)
+[ ]*[0-9a-f]+:[ ]+81 00 00 ff ff ff addl \$0xffffff00,\(%eax\)[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+81 02 00 ff ff ff addl \$0xffffff00,\(%edx\)[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+81 00 f4 00 00 00 addl \$0xf4,\(%eax\)[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+81 02 f4 00 00 00 addl \$0xf4,\(%edx\)[ ]+[0-9a-f]+: (R_386_32|dir32)[ ]+sym
+[ ]*[0-9a-f]+:[ ]+c3 ret *
+#pass
--- /dev/null
+++ b/gas/testsuite/gas/i386/wrap32.s
@@ -0,0 +1,60 @@
+ .text
+wrap:
+ mov $500 - 0x100, %eax
+ mov $500 + 0xffffff00, %edx
+ mov $val - 0x100, %eax
+ mov $val + 0xffffff00, %edx
+ mov $sym - 0x100, %eax
+ mov $sym + 0xffffff00, %edx
+ mov $sym + 500 - 0x100, %eax
+ mov $sym + 500 + 0xffffff00, %edx
+
+ movl $500 - 0x100, (%eax)
+ movl $500 + 0xffffff00, (%edx)
+ movl $val - 0x100, (%eax)
+ movl $val + 0xffffff00, (%edx)
+ movl $sym - 0x100, (%eax)
+ movl $sym + 0xffffff00, (%edx)
+ movl $sym + 500 - 0x100, (%eax)
+ movl $sym + 500 + 0xffffff00, (%edx)
+
+ add $500 - 0x100, %ecx
+ add $500 + 0xffffff00, %edx
+ add $val - 0x100, %ecx
+ add $val + 0xffffff00, %edx
+ add $sym - 0x100, %ecx
+ add $sym + 0xffffff00, %edx
+ add $sym + 500 - 0x100, %ecx
+ add $sym + 500 + 0xffffff00, %edx
+
+ addl $500 - 0x100, (%eax)
+ addl $500 + 0xffffff00, (%edx)
+ addl $val - 0x100, (%eax)
+ addl $val + 0xffffff00, (%edx)
+ addl $sym - 0x100, (%eax)
+ addl $sym + 0xffffff00, (%edx)
+ addl $sym + 500 - 0x100, (%eax)
+ addl $sym + 500 + 0xffffff00, (%edx)
+
+ ret
+
+ .data
+ .long 500 - 0x100
+ .long 500 + 0xffffff00
+ .long val - 0x100
+ .long val + 0xffffff00
+ .long sym - 0x100
+ .long sym + 0xffffff00
+ .long sym + 500 - 0x100
+ .long sym + 500 + 0xffffff00
+
+ .slong 500 - 0x8fffff00
+ .slong 500 + 0x7fffff00
+ .slong val - 0x8fffff00
+ .slong val + 0x7fffff00
+ .slong sym - 0x8fffff00
+ .slong sym + 0x7fffff00
+ .slong sym + 500 - 0x8fffff00
+ .slong sym + 500 + 0x7fffff00
+
+ .equ val, 400
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