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* config/tc-i386.c (output_insn): Save frag_now and frag_now_fix () 

at start of insn, pass it to output_disp and output_imm.
	(output_disp): Added arguments.  If _GLOBAL_OFFSET_TABLE_ is seen
	in displacement for R_386_32 reloc, use R_386_GOTPC and compute
	properly addend.
	(output_imm): Added arguments.  Compute properly addend for
	R_386_GOTPC.
	(md_apply_fix3): Remove R_386_GOTPC handling.
	* testsuite/gas/i386/gotpc.s: New.
	* testsuite/gas/i386/gotpc.d: New.
	* testsuite/gas/i386/i386.exp: Add gotpc test.
drow-cplus-branch
Jakub Jelinek 24 years ago
parent
9bf279ebdd
commit
2bbd9c2554
5 changed files with 219 additions and 51 deletions
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  1. 14
      gas/ChangeLog
  2. 163
      gas/config/tc-i386.c
  3. 52
      gas/testsuite/gas/i386/gotpc.d
  4. 40
      gas/testsuite/gas/i386/gotpc.s
  5. 1
      gas/testsuite/gas/i386/i386.exp

14
gas/ChangeLog
View File

@ -1,3 +1,17 @@
2002-08-09 Jakub Jelinek <jakub@redhat.com>
* config/tc-i386.c (output_insn): Save frag_now and frag_now_fix ()
at start of insn, pass it to output_disp and output_imm.
(output_disp): Added arguments. If _GLOBAL_OFFSET_TABLE_ is seen
in displacement for R_386_32 reloc, use R_386_GOTPC and compute
properly addend.
(output_imm): Added arguments. Compute properly addend for
R_386_GOTPC.
(md_apply_fix3): Remove R_386_GOTPC handling.
* testsuite/gas/i386/gotpc.s: New.
* testsuite/gas/i386/gotpc.d: New.
* testsuite/gas/i386/i386.exp: Add gotpc test.
2002-08-06 George France <france@handhelds.org>
* config/tc-alpha.c (cpu_types): Enabled ev67, ev68, -m21264a

163
gas/config/tc-i386.c
View File

@ -104,8 +104,10 @@ static void output_insn PARAMS ((void));
static void output_branch PARAMS ((void));
static void output_jump PARAMS ((void));
static void output_interseg_jump PARAMS ((void));
static void output_imm PARAMS ((void));
static void output_disp PARAMS ((void));
static void output_imm PARAMS ((fragS *insn_start_frag,
offsetT insn_start_off));
static void output_disp PARAMS ((fragS *insn_start_frag,
offsetT insn_start_off));
#ifndef I386COFF
static void s_bss PARAMS ((int));
#endif
@ -3101,14 +3103,21 @@ output_interseg_jump ()
md_number_to_chars (p + size, (valueT) i.op[0].imms->X_add_number, 2);
}
static void
output_insn ()
{
fragS *insn_start_frag;
offsetT insn_start_off;
/* Tie dwarf2 debug info to the address at the start of the insn.
We can't do this after the insn has been output as the current
frag may have been closed off. eg. by frag_var. */
dwarf2_emit_insn (0);
insn_start_frag = frag_now;
insn_start_off = frag_now_fix ();
/* Output jumps. */
if (i.tm.opcode_modifier & Jump)
output_branch ();
@ -3179,10 +3188,10 @@ output_insn ()
}
if (i.disp_operands)
output_disp ();
output_disp (insn_start_frag, insn_start_off);
if (i.imm_operands)
output_imm ();
output_imm (insn_start_frag, insn_start_off);
}
#ifdef DEBUG386
@ -3194,7 +3203,9 @@ output_insn ()
}
static void
output_disp ()
output_disp (insn_start_frag, insn_start_off)
fragS *insn_start_frag;
offsetT insn_start_off;
{
char *p;
unsigned int n;
@ -3224,6 +3235,7 @@ output_disp ()
}
else
{
RELOC_ENUM reloc_type;
int size = 4;
int sign = 0;
int pcrel = (i.flags[n] & Operand_PCrel) != 0;
@ -3266,16 +3278,50 @@ output_disp ()
}
p = frag_more (size);
reloc_type = reloc (size, pcrel, sign, i.reloc[n]);
#ifdef BFD_ASSEMBLER
if (reloc_type == BFD_RELOC_32
&& GOT_symbol
&& GOT_symbol == i.op[n].disps->X_add_symbol
&& (i.op[n].disps->X_op == O_symbol
|| (i.op[n].disps->X_op == O_add
&& ((symbol_get_value_expression
(i.op[n].disps->X_op_symbol)->X_op)
== O_subtract))))
{
offsetT add;
if (insn_start_frag == frag_now)
add = (p - frag_now->fr_literal) - insn_start_off;
else
{
fragS *fr;
add = insn_start_frag->fr_fix - insn_start_off;
for (fr = insn_start_frag->fr_next;
fr && fr != frag_now; fr = fr->fr_next)
add += fr->fr_fix;
add += p - frag_now->fr_literal;
}
/* We don't support dynamic linking on x86-64 yet. */
if (flag_code == CODE_64BIT)
abort ();
reloc_type = BFD_RELOC_386_GOTPC;
i.op[n].disps->X_add_number += add;
}
#endif
fix_new_exp (frag_now, p - frag_now->fr_literal, size,
i.op[n].disps, pcrel,
reloc (size, pcrel, sign, i.reloc[n]));
i.op[n].disps, pcrel, reloc_type);
}
}
}
}
static void
output_imm ()
output_imm (insn_start_frag, insn_start_off)
fragS *insn_start_frag;
offsetT insn_start_off;
{
char *p;
unsigned int n;
@ -3328,6 +3374,48 @@ output_imm ()
p = frag_more (size);
reloc_type = reloc (size, 0, sign, i.reloc[n]);
#ifdef BFD_ASSEMBLER
/* This is tough to explain. We end up with this one if we
* have operands that look like
* "_GLOBAL_OFFSET_TABLE_+[.-.L284]". The goal here is to
* obtain the absolute address of the GOT, and it is strongly
* preferable from a performance point of view to avoid using
* a runtime relocation for this. The actual sequence of
* instructions often look something like:
*
* call .L66
* .L66:
* popl %ebx
* addl $_GLOBAL_OFFSET_TABLE_+[.-.L66],%ebx
*
* The call and pop essentially return the absolute address
* of the label .L66 and store it in %ebx. The linker itself
* will ultimately change the first operand of the addl so
* that %ebx points to the GOT, but to keep things simple, the
* .o file must have this operand set so that it generates not
* the absolute address of .L66, but the absolute address of
* itself. This allows the linker itself simply treat a GOTPC
* relocation as asking for a pcrel offset to the GOT to be
* added in, and the addend of the relocation is stored in the
* operand field for the instruction itself.
*
* Our job here is to fix the operand so that it would add
* the correct offset so that %ebx would point to itself. The
* thing that is tricky is that .-.L66 will point to the
* beginning of the instruction, so we need to further modify
* the operand so that it will point to itself. There are
* other cases where you have something like:
*
* .long $_GLOBAL_OFFSET_TABLE_+[.-.L66]
*
* and here no correction would be required. Internally in
* the assembler we treat operands of this form as not being
* pcrel since the '.' is explicitly mentioned, and I wonder
* whether it would simplify matters to do it this way. Who
* knows. In earlier versions of the PIC patches, the
* pcrel_adjust field was used to store the correction, but
* since the expression is not pcrel, I felt it would be
* confusing to do it this way. */
if (reloc_type == BFD_RELOC_32
&& GOT_symbol
&& GOT_symbol == i.op[n].imms->X_add_symbol
@ -3337,11 +3425,26 @@ output_imm ()
(i.op[n].imms->X_op_symbol)->X_op)
== O_subtract))))
{
offsetT add;
if (insn_start_frag == frag_now)
add = (p - frag_now->fr_literal) - insn_start_off;
else
{
fragS *fr;
add = insn_start_frag->fr_fix - insn_start_off;
for (fr = insn_start_frag->fr_next;
fr && fr != frag_now; fr = fr->fr_next)
add += fr->fr_fix;
add += p - frag_now->fr_literal;
}
/* We don't support dynamic linking on x86-64 yet. */
if (flag_code == CODE_64BIT)
abort ();
reloc_type = BFD_RELOC_386_GOTPC;
i.op[n].imms->X_add_number += 3;
i.op[n].imms->X_add_number += add;
}
#endif
fix_new_exp (frag_now, p - frag_now->fr_literal, size,
@ -4542,48 +4645,6 @@ md_apply_fix3 (fixP, valP, seg)
runtime we merely add the offset to the actual PLT entry. */
value = -4;
break;
case BFD_RELOC_386_GOTPC:
/* This is tough to explain. We end up with this one if we have
* operands that look like "_GLOBAL_OFFSET_TABLE_+[.-.L284]". The goal
* here is to obtain the absolute address of the GOT, and it is strongly
* preferable from a performance point of view to avoid using a runtime
* relocation for this. The actual sequence of instructions often look
* something like:
*
* call .L66
* .L66:
* popl %ebx
* addl $_GLOBAL_OFFSET_TABLE_+[.-.L66],%ebx
*
* The call and pop essentially return the absolute address of
* the label .L66 and store it in %ebx. The linker itself will
* ultimately change the first operand of the addl so that %ebx points to
* the GOT, but to keep things simple, the .o file must have this operand
* set so that it generates not the absolute address of .L66, but the
* absolute address of itself. This allows the linker itself simply
* treat a GOTPC relocation as asking for a pcrel offset to the GOT to be
* added in, and the addend of the relocation is stored in the operand
* field for the instruction itself.
*
* Our job here is to fix the operand so that it would add the correct
* offset so that %ebx would point to itself. The thing that is tricky is
* that .-.L66 will point to the beginning of the instruction, so we need
* to further modify the operand so that it will point to itself.
* There are other cases where you have something like:
*
* .long $_GLOBAL_OFFSET_TABLE_+[.-.L66]
*
* and here no correction would be required. Internally in the assembler
* we treat operands of this form as not being pcrel since the '.' is
* explicitly mentioned, and I wonder whether it would simplify matters
* to do it this way. Who knows. In earlier versions of the PIC patches,
* the pcrel_adjust field was used to store the correction, but since the
* expression is not pcrel, I felt it would be confusing to do it this
* way. */
value -= 1;
break;
case BFD_RELOC_386_GOT32:
case BFD_RELOC_386_TLS_GD:
case BFD_RELOC_386_TLS_LDM:

52
gas/testsuite/gas/i386/gotpc.d
View File

@ -0,0 +1,52 @@
#objdump: -drw
#name: i386 gotpc
.*: +file format .*
Disassembly of section .text:
0+000 <test>:
0: 05 01 00 00 00 [ ]*add \$0x1,%eax 1: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
5: 81 c3 07 00 00 00 [ ]*add \$0x7,%ebx 7: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
b: 05 01 00 00 00 [ ]*add \$0x1,%eax c: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
10: 81 c3 02 00 00 00 [ ]*add \$0x2,%ebx 12: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
16: 8d 98 18 00 00 00 [ ]*lea 0x18\(%eax\),%ebx 18: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
1c: 8d 83 1e 00 00 00 [ ]*lea 0x1e\(%ebx\),%eax 1e: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
22: 8d 80 24 00 00 00 [ ]*lea 0x24\(%eax\),%eax 24: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
28: 8d 9b 2a 00 00 00 [ ]*lea 0x2a\(%ebx\),%ebx 2a: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
2e: 2d 2f 00 00 00 [ ]*sub \$0x2f,%eax 2f: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
33: 81 eb 35 00 00 00 [ ]*sub \$0x35,%ebx 35: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
39: 2d 01 00 00 00 [ ]*sub \$0x1,%eax 3a: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
3e: 81 eb 02 00 00 00 [ ]*sub \$0x2,%ebx 40: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
44: 0d 45 00 00 00 [ ]*or \$0x45,%eax 45: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
49: 81 cb 4b 00 00 00 [ ]*or \$0x4b,%ebx 4b: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
4f: 0d 01 00 00 00 [ ]*or \$0x1,%eax 50: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
54: 81 cb 02 00 00 00 [ ]*or \$0x2,%ebx 56: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
5a: b8 5b 00 00 00 [ ]*mov \$0x5b,%eax 5b: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
5f: bb 60 00 00 00 [ ]*mov \$0x60,%ebx 60: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
64: b8 01 00 00 00 [ ]*mov \$0x1,%eax 65: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
69: bb 01 00 00 00 [ ]*mov \$0x1,%ebx 6a: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
6e: c7 05 00 00 00 00 74 00 00 00 [ ]*movl \$0x74,0x0 70: (R_386_)?(dir)?32 foo
[ ]*74: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
78: 65 c7 05 00 00 00 00 7f 00 00 00 [ ]*movl \$0x7f,%gs:0x0 7b: (R_386_)?(dir)?32 foo
[ ]*7f: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
83: 65 c7 05 00 00 00 00 8a 00 00 00 [ ]*movl \$0x8a,%gs:0x0 86: (R_386_)?(dir)?32 foo
[ ]*8a: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
8e: c7 05 02 00 00 00 94 00 00 00 [ ]*movl \$0x94,0x2 90: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
[ ]*94: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
98: a1 99 00 00 00 [ ]*mov 0x99,%eax 99: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
9d: 8b 1d 9f 00 00 00 [ ]*mov 0x9f,%ebx 9f: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
a3: a3 a4 00 00 00 [ ]*mov %eax,0xa4 a4: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
a8: 89 1d aa 00 00 00 [ ]*mov %ebx,0xaa aa: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
ae: 65 a3 b0 00 00 00 [ ]*mov %eax,%gs:0xb0 b0: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
b4: 65 89 1d b7 00 00 00 [ ]*mov %ebx,%gs:0xb7 b7: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
bb: 65 a3 bd 00 00 00 [ ]*mov %eax,%gs:0xbd bd: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
c1: 65 89 1d c4 00 00 00 [ ]*mov %ebx,%gs:0xc4 c4: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
c8: 8d 83 00 00 00 00 [ ]*lea 0x0\(%ebx\),%eax ca: (R_386_)?GOTOFF _GLOBAL_OFFSET_TABLE_
ce: 8d 9b 00 00 00 00 [ ]*lea 0x0\(%ebx\),%ebx d0: (R_386_)?GOTOFF _GLOBAL_OFFSET_TABLE_
d4: 8b 83 00 00 00 00 [ ]*mov 0x0\(%ebx\),%eax d6: (R_386_)?GOTOFF _GLOBAL_OFFSET_TABLE_
da: 8b 9b 00 00 00 00 [ ]*mov 0x0\(%ebx\),%ebx dc: (R_386_)?GOTOFF _GLOBAL_OFFSET_TABLE_
e0: e0 00 [ ]*loopne e2 <test\+0xe2> e0: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_
e2: 00 00 [ ]*add %al,\(%eax\)
e4: 00 00 [ ]*add %al,\(%eax\) e4: (R_386_)?GOTOFF _GLOBAL_OFFSET_TABLE_
...

40
gas/testsuite/gas/i386/gotpc.s
View File

@ -0,0 +1,40 @@
.text
test:
addl $_GLOBAL_OFFSET_TABLE_+[.-test], %eax
addl $_GLOBAL_OFFSET_TABLE_+[.-test], %ebx
addl $_GLOBAL_OFFSET_TABLE_, %eax
addl $_GLOBAL_OFFSET_TABLE_, %ebx
leal _GLOBAL_OFFSET_TABLE_+[.-test](%eax), %ebx
leal _GLOBAL_OFFSET_TABLE_+[.-test](%ebx), %eax
leal _GLOBAL_OFFSET_TABLE_+[.-test](%eax), %eax
leal _GLOBAL_OFFSET_TABLE_+[.-test](%ebx), %ebx
subl $_GLOBAL_OFFSET_TABLE_+[.-test], %eax
subl $_GLOBAL_OFFSET_TABLE_+[.-test], %ebx
subl $_GLOBAL_OFFSET_TABLE_, %eax
subl $_GLOBAL_OFFSET_TABLE_, %ebx
orl $_GLOBAL_OFFSET_TABLE_+[.-test], %eax
orl $_GLOBAL_OFFSET_TABLE_+[.-test], %ebx
orl $_GLOBAL_OFFSET_TABLE_, %eax
orl $_GLOBAL_OFFSET_TABLE_, %ebx
movl $_GLOBAL_OFFSET_TABLE_+[.-test], %eax
movl $_GLOBAL_OFFSET_TABLE_+[.-test], %ebx
movl $_GLOBAL_OFFSET_TABLE_, %eax
movl $_GLOBAL_OFFSET_TABLE_, %ebx
movl $_GLOBAL_OFFSET_TABLE_+[.-test], foo
movl $_GLOBAL_OFFSET_TABLE_+[.-test], %gs:foo
gs; movl $_GLOBAL_OFFSET_TABLE_+[.-test], foo
movl $_GLOBAL_OFFSET_TABLE_+[.-test], _GLOBAL_OFFSET_TABLE_
movl _GLOBAL_OFFSET_TABLE_+[.-test], %eax
movl _GLOBAL_OFFSET_TABLE_+[.-test], %ebx
movl %eax, _GLOBAL_OFFSET_TABLE_+[.-test]
movl %ebx, _GLOBAL_OFFSET_TABLE_+[.-test]
movl %eax, %gs:_GLOBAL_OFFSET_TABLE_+[.-test]
movl %ebx, %gs:_GLOBAL_OFFSET_TABLE_+[.-test]
gs; movl %eax, _GLOBAL_OFFSET_TABLE_+[.-test]
gs; movl %ebx, _GLOBAL_OFFSET_TABLE_+[.-test]
leal _GLOBAL_OFFSET_TABLE_@GOTOFF(%ebx), %eax
leal _GLOBAL_OFFSET_TABLE_@GOTOFF(%ebx), %ebx
movl _GLOBAL_OFFSET_TABLE_@GOTOFF(%ebx), %eax
movl _GLOBAL_OFFSET_TABLE_@GOTOFF(%ebx), %ebx
.long _GLOBAL_OFFSET_TABLE_+[.-test]
.long _GLOBAL_OFFSET_TABLE_@GOTOFF

1
gas/testsuite/gas/i386/i386.exp
View File

@ -76,6 +76,7 @@ if [expr ([istarget "i*86-*-*"] || [istarget "x86_64-*-*"]) && [gas_32_check]]
&& ![istarget *-*-linux*oldld*])
} then {
run_dump_test "relax"
run_dump_test "gotpc"
run_dump_test "tlsd"
run_dump_test "tlspic"
run_dump_test "tlsnopic"

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