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PowerPC notoc linkage stubs

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Use pcrel addressing instructions in linkage stubs.

bfd/
	* elf64-ppc.c: Comment on powerxx _notoc stub variants.
	(LI_R11_0, LIS_R11, ORI_R11_R11_0, SLDI_R11_R11_34): Define.
	(PADDI_R12_PC, PLD_R12_PC, D34, HA34): Define.
	(struct ppc_link_hash_table): Add powerxx_stubs.
	(ppc64_elf_check_relocs): Set powerxx_stubs.
	(build_powerxx_offset, size_powerxx_offset),
	(num_relocs_for_powerxx_offset),
	(emit_relocs_for_powerxx_offset): New functions.
	(plt_stub_size): Size powerxx stubs.
	(ppc_build_one_stub): Emit powerxx stubs.
	(ppc_size_one_stub): Size powerxx stubs.  Omit .eh_frame for
	powerxx stubs.
ld/
	* testsuite/ld-powerpc/notoc2.d,
	* testsuite/ld-powerpc/notoc2.s: New test.
	* testsuite/ld-powerpc/powerpc.exp: Run it.
This commit is contained in:
Alan Modra
2018-08-09 22:53:00 +09:30
parent 4a421c53cf
commit 04bdff6a76
6 changed files with 346 additions and 43 deletions
Download Patch File Download Diff File Expand all files Collapse all files
bfd/ChangeLog
+15
View File
@@ -1,3 +1,18 @@
2019-05-24 Alan Modra <amodra@gmail.com>
* elf64-ppc.c: Comment on powerxx _notoc stub variants.
(LI_R11_0, LIS_R11, ORI_R11_R11_0, SLDI_R11_R11_34): Define.
(PADDI_R12_PC, PLD_R12_PC, D34, HA34): Define.
(struct ppc_link_hash_table): Add powerxx_stubs.
(ppc64_elf_check_relocs): Set powerxx_stubs.
(build_powerxx_offset, size_powerxx_offset),
(num_relocs_for_powerxx_offset),
(emit_relocs_for_powerxx_offset): New functions.
(plt_stub_size): Size powerxx stubs.
(ppc_build_one_stub): Emit powerxx stubs.
(ppc_size_one_stub): Size powerxx stubs. Omit .eh_frame for
powerxx stubs.
2019-05-24 Alan Modra <amodra@gmail.com>
* elf64-ppc.c (ppc64_elf_check_relocs): Set has_gotrel for
bfd/elf64-ppc.c
+281 -43
View File
@@ -187,18 +187,24 @@ static bfd_vma opd_entry_value
#define LD_R2_0R12 0xe84c0000 /* ld %r2,0(%r12) */
#define ADD_R2_R2_R12 0x7c426214 /* add %r2,%r2,%r12 */
#define LI_R11_0 0x39600000 /* li %r11,0 */
#define LIS_R2 0x3c400000 /* lis %r2,xxx@ha */
#define LIS_R11 0x3d600000 /* lis %r11,xxx@ha */
#define LIS_R12 0x3d800000 /* lis %r12,xxx@ha */
#define ADDIS_R2_R12 0x3c4c0000 /* addis %r2,%r12,xxx@ha */
#define ADDIS_R12_R2 0x3d820000 /* addis %r12,%r2,xxx@ha */
#define ADDIS_R12_R11 0x3d8b0000 /* addis %r12,%r11,xxx@ha */
#define ADDIS_R12_R12 0x3d8c0000 /* addis %r12,%r12,xxx@ha */
#define ORIS_R12_R12_0 0x658c0000 /* oris %r12,%r12,xxx@hi */
#define ORI_R11_R11_0 0x616b0000 /* ori %r11,%r11,xxx@l */
#define ORI_R12_R12_0 0x618c0000 /* ori %r12,%r12,xxx@l */
#define LD_R12_0R12 0xe98c0000 /* ld %r12,xxx@l(%r12) */
#define SLDI_R11_R11_34 0x796b1746 /* sldi %r11,%r11,34 */
#define SLDI_R12_R12_32 0x799c07c6 /* sldi %r12,%r12,32 */
#define LDX_R12_R11_R12 0x7d8b602a /* ldx %r12,%r11,%r12 */
#define ADD_R12_R11_R12 0x7d8b6214 /* add %r12,%r11,%r12 */
#define PADDI_R12_PC 0x0610000039800000ULL
#define PLD_R12_PC 0x04100000e5800000ULL
#define PNOP 0x0700000000000000ULL
/* __glink_PLTresolve stub instructions. We enter with the index in R0. */
@@ -2841,8 +2847,34 @@ must_be_dyn_reloc (struct bfd_link_info *info,
. mtctr %r12
. bctr
There are also ELFv1 powerxx variants of these stubs.
ppc_stub_long_branch_notoc:
. paddi %r12,dest@pcrel
. b dest
ppc_stub_plt_branch_notoc:
. lis %r11,(dest-1f)@highesta34
. ori %r11,%r11,(dest-1f)@highera34
. sldi %r11,%r11,34
. 1: paddi %r12,dest@pcrel
. add %r12,%r11,%r12
. mtctr %r12
. bctr
ppc_stub_plt_call_notoc:
. lis %r11,(xxx-1f)@highesta34
. ori %r11,%r11,(xxx-1f)@highera34
. sldi %r11,%r11,34
. 1: paddi %r12,xxx@pcrel
. ldx %r12,%r11,%r12
. mtctr %r12
. bctr
In cases where the high instructions would add zero, they are
omitted and following instructions modified in some cases.
For example, a powerxx ppc_stub_plt_call_notoc might simplify down
to
. pld %r12,xxx@pcrel
. mtctr %r12
. bctr
For a given stub group (a set of sections all using the same toc
pointer value) there will be just one stub type used for any
@@ -3132,6 +3164,9 @@ struct ppc_link_hash_table
/* Whether calls are made via the PLT from NOTOC functions. */
unsigned int notoc_plt:1;
/* Whether to use powerxx instructions in linkage stubs. */
unsigned int powerxx_stubs:1;
/* Incremented every time we size stubs. */
unsigned int stub_iteration;
@@ -4476,6 +4511,13 @@ ppc64_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
r_type = ELF64_R_TYPE (rel->r_info);
switch (r_type)
{
case R_PPC64_D34:
case R_PPC64_D34_LO:
case R_PPC64_D34_HI30:
case R_PPC64_D34_HA30:
case R_PPC64_D28:
htab->powerxx_stubs = 1;
/* Fall through. */
default:
/* Somewhat foolishly, because the ABIs don't specifically
allow it, ppc64 gas and ld support GOT and PLT relocs
@@ -4485,9 +4527,13 @@ ppc64_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
used to specify the pcrel offset. */
sym_addend = rel->r_addend;
break;
case R_PPC64_PCREL34:
case R_PPC64_GOT_PCREL34:
case R_PPC64_PLT_PCREL34:
case R_PPC64_PLT_PCREL34_NOTOC:
case R_PPC64_PCREL28:
htab->powerxx_stubs = 1;
sym_addend = 0;
break;
}
@@ -9427,6 +9473,9 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
#define PPC_LO(v) ((v) & 0xffff)
#define PPC_HI(v) (((v) >> 16) & 0xffff)
#define PPC_HA(v) PPC_HI ((v) + 0x8000)
#define D34(v) \
((((v) & 0x3ffff0000ULL) << 16) | (v & 0xffff))
#define HA34(v) ((v + (1ULL << 33)) >> 34)
/* Called via elf_link_hash_traverse from ppc64_elf_size_dynamic_sections
to set up space for global entry stubs. These are put in glink,
@@ -10208,6 +10257,146 @@ emit_relocs_for_offset (struct bfd_link_info *info, Elf_Internal_Rela *r,
return r;
}
static bfd_byte *
build_powerxx_offset (bfd *abfd, bfd_byte *p, bfd_vma off, int odd,
bfd_boolean load)
{
uint64_t insn;
if (off - odd + (1ULL << 33) < 1ULL << 34)
{
off -= odd;
if (odd)
{
bfd_put_32 (abfd, NOP, p);
p += 4;
}
if (load)
insn = PLD_R12_PC;
else
insn = PADDI_R12_PC;
insn |= D34 (off);
bfd_put_32 (abfd, insn >> 32, p);
p += 4;
bfd_put_32 (abfd, insn, p);
}
/* The minimum value for paddi is -0x200000000. The minimum value
for li is -0x8000, which when shifted by 34 and added gives a
minimum value of -0x2000200000000. The maximum value is
0x1ffffffff+0x7fff<<34 which is 0x2000200000000-1. */
else if (off - (8 - odd) + (0x20002ULL << 32) < 0x40004ULL << 32)
{
off -= 8 - odd;
bfd_put_32 (abfd, LI_R11_0 | (HA34 (off) & 0xffff), p);
p += 4;
if (!odd)
{
bfd_put_32 (abfd, SLDI_R11_R11_34, p);
p += 4;
}
insn = PADDI_R12_PC | D34 (off);
bfd_put_32 (abfd, insn >> 32, p);
p += 4;
bfd_put_32 (abfd, insn, p);
p += 4;
if (odd)
{
bfd_put_32 (abfd, SLDI_R11_R11_34, p);
p += 4;
}
if (load)
bfd_put_32 (abfd, LDX_R12_R11_R12, p);
else
bfd_put_32 (abfd, ADD_R12_R11_R12, p);
}
else
{
off -= odd + 8;
bfd_put_32 (abfd, LIS_R11 | ((HA34 (off) >> 16) & 0x3fff), p);
p += 4;
bfd_put_32 (abfd, ORI_R11_R11_0 | (HA34 (off) & 0xffff), p);
p += 4;
if (odd)
{
bfd_put_32 (abfd, SLDI_R11_R11_34, p);
p += 4;
}
insn = PADDI_R12_PC | D34 (off);
bfd_put_32 (abfd, insn >> 32, p);
p += 4;
bfd_put_32 (abfd, insn, p);
p += 4;
if (!odd)
{
bfd_put_32 (abfd, SLDI_R11_R11_34, p);
p += 4;
}
if (load)
bfd_put_32 (abfd, LDX_R12_R11_R12, p);
else
bfd_put_32 (abfd, ADD_R12_R11_R12, p);
}
p += 4;
return p;
}
static unsigned int
size_powerxx_offset (bfd_vma off, int odd)
{
if (off - odd + (1ULL << 33) < 1ULL << 34)
return odd + 8;
else if (off - (8 - odd) + (0x20002ULL << 32) < 0x40004ULL << 32)
return 20;
else
return 24;
}
static unsigned int
num_relocs_for_powerxx_offset (bfd_vma off, int odd)
{
if (off - odd + (1ULL << 33) < 1ULL << 34)
return 1;
else if (off - (8 - odd) + (0x20002ULL << 32) < 0x40004ULL << 32)
return 2;
else
return 3;
}
static Elf_Internal_Rela *
emit_relocs_for_powerxx_offset (struct bfd_link_info *info,
Elf_Internal_Rela *r, bfd_vma roff,
bfd_vma targ, bfd_vma off, int odd)
{
if (off - odd + (1ULL << 33) < 1ULL << 34)
roff += odd;
else if (off - (8 - odd) + (0x20002ULL << 32) < 0x40004ULL << 32)
{
int d_offset = bfd_big_endian (info->output_bfd) ? 2 : 0;
r->r_offset = roff + d_offset;
r->r_addend = targ + 8 - odd - d_offset;
r->r_info = ELF64_R_INFO (0, R_PPC64_REL16_HIGHERA34);
++r;
roff += 8 - odd;
}
else
{
int d_offset = bfd_big_endian (info->output_bfd) ? 2 : 0;
r->r_offset = roff + d_offset;
r->r_addend = targ + 8 + odd - d_offset;
r->r_info = ELF64_R_INFO (0, R_PPC64_REL16_HIGHESTA34);
++r;
roff += 4;
r->r_offset = roff + d_offset;
r->r_addend = targ + 4 + odd - d_offset;
r->r_info = ELF64_R_INFO (0, R_PPC64_REL16_HIGHERA34);
++r;
roff += 4 + odd;
}
r->r_offset = roff;
r->r_addend = targ;
r->r_info = ELF64_R_INFO (0, R_PPC64_PCREL34);
return r;
}
/* Emit .eh_frame opcode to advance pc by DELTA. */
static bfd_byte *
@@ -10285,7 +10474,17 @@ plt_stub_size (struct ppc_link_hash_table *htab,
if (stub_entry->stub_type >= ppc_stub_plt_call_notoc)
{
size = 8 + size_offset (off - 8);
if (htab->powerxx_stubs)
{
bfd_vma start = (stub_entry->stub_offset
+ stub_entry->group->stub_sec->output_offset
+ stub_entry->group->stub_sec->output_section->vma);
if (stub_entry->stub_type > ppc_stub_plt_call_notoc)
start += 4;
size = 8 + size_powerxx_offset (off, start & 4);
}
else
size = 8 + size_offset (off - 8);
if (stub_entry->stub_type > ppc_stub_plt_call_notoc)
size += 4;
return size;
@@ -10738,6 +10937,7 @@ ppc_build_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
Elf_Internal_Rela *r;
asection *plt;
int num_rel;
int odd;
/* Massage our args to the form they really have. */
stub_entry = (struct ppc_stub_hash_entry *) gen_entry;
@@ -11016,18 +11216,28 @@ ppc_build_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
targ = (stub_entry->target_value
+ stub_entry->target_section->output_offset
+ stub_entry->target_section->output_section->vma);
odd = off & 4;
off = targ - off;
relp = p;
num_rel = 0;
/* The notoc stubs calculate their target (either a PLT entry or
the global entry point of a function) relative to the PC
returned by the "bcl" two instructions past the start of the
sequence emitted by build_offset. The offset is therefore 8
less than calculated from the start of the sequence. */
off -= 8;
p = build_offset (htab->params->stub_bfd, p, off,
stub_entry->stub_type >= ppc_stub_plt_call_notoc);
if (htab->powerxx_stubs)
{
bfd_boolean load = stub_entry->stub_type >= ppc_stub_plt_call_notoc;
p = build_powerxx_offset (htab->params->stub_bfd, p, off, odd, load);
}
else
{
/* The notoc stubs calculate their target (either a PLT entry or
the global entry point of a function) relative to the PC
returned by the "bcl" two instructions past the start of the
sequence emitted by build_offset. The offset is therefore 8
less than calculated from the start of the sequence. */
off -= 8;
p = build_offset (htab->params->stub_bfd, p, off,
stub_entry->stub_type >= ppc_stub_plt_call_notoc);
}
if (stub_entry->stub_type <= ppc_stub_long_branch_both)
{
bfd_vma from;
@@ -11049,13 +11259,21 @@ ppc_build_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
if (info->emitrelocations)
{
bfd_vma roff;
num_rel += num_relocs_for_offset (off);
bfd_vma roff = relp - stub_entry->group->stub_sec->contents;
if (htab->powerxx_stubs)
num_rel += num_relocs_for_powerxx_offset (off, odd);
else
{
num_rel += num_relocs_for_offset (off);
roff += 16;
}
r = get_relocs (stub_entry->group->stub_sec, num_rel);
if (r == NULL)
return FALSE;
roff = relp + 16 - stub_entry->group->stub_sec->contents;
r = emit_relocs_for_offset (info, r, roff, targ, off);
if (htab->powerxx_stubs)
r = emit_relocs_for_powerxx_offset (info, r, roff, targ, off, odd);
else
r = emit_relocs_for_offset (info, r, roff, targ, off);
if (stub_entry->stub_type == ppc_stub_long_branch_notoc
|| stub_entry->stub_type == ppc_stub_long_branch_both)
{
@@ -11070,8 +11288,9 @@ ppc_build_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
}
}
if (htab->glink_eh_frame != NULL
&& htab->glink_eh_frame->size != 0)
if (!htab->powerxx_stubs
&& htab->glink_eh_frame != NULL
&& htab->glink_eh_frame->size != 0)
{
bfd_byte *base, *eh;
unsigned int lr_used, delta;
@@ -11240,7 +11459,7 @@ ppc_size_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
struct ppc_link_hash_table *htab;
asection *plt;
bfd_vma targ, off, r2off;
unsigned int size, extra, lr_used, delta;
unsigned int size, extra, lr_used, delta, odd;
/* Massage our args to the form they really have. */
stub_entry = (struct ppc_stub_hash_entry *) gen_entry;
@@ -11393,16 +11612,24 @@ ppc_size_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
targ = (stub_entry->target_value
+ stub_entry->target_section->output_offset
+ stub_entry->target_section->output_section->vma);
odd = off & 4;
off = targ - off;
if (info->emitrelocations)
{
stub_entry->group->stub_sec->reloc_count
+= num_relocs_for_offset (off);
unsigned int num_rel;
if (htab->powerxx_stubs)
num_rel = num_relocs_for_powerxx_offset (off, odd);
else
num_rel = num_relocs_for_offset (off - 8);
stub_entry->group->stub_sec->reloc_count += num_rel;
stub_entry->group->stub_sec->flags |= SEC_RELOC;
}
extra = size_offset (off - 8);
if (htab->powerxx_stubs)
extra = size_powerxx_offset (off, odd);
else
extra = size_offset (off - 8);
/* Include branch insn plus those in the offset sequence. */
size += 4 + extra;
/* The branch insn is at the end, or "extra" bytes along. So
@@ -11410,17 +11637,20 @@ ppc_size_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
calculated. */
off -= extra;
/* After the bcl, lr has been modified so we need to emit
.eh_frame info saying the return address is in r12. */
lr_used = stub_entry->stub_offset + 8;
if (stub_entry->stub_type == ppc_stub_long_branch_both)
lr_used += 4;
/* The eh_frame info will consist of a DW_CFA_advance_loc or
variant, DW_CFA_register, 65, 12, DW_CFA_advance_loc+2,
DW_CFA_restore_extended 65. */
delta = lr_used - stub_entry->group->lr_restore;
stub_entry->group->eh_size += eh_advance_size (delta) + 6;
stub_entry->group->lr_restore = lr_used + 8;
if (!htab->powerxx_stubs)
{
/* After the bcl, lr has been modified so we need to emit
.eh_frame info saying the return address is in r12. */
lr_used = stub_entry->stub_offset + 8;
if (stub_entry->stub_type == ppc_stub_long_branch_both)
lr_used += 4;
/* The eh_frame info will consist of a DW_CFA_advance_loc or
variant, DW_CFA_register, 65, 12, DW_CFA_advance_loc+2,
DW_CFA_restore_extended 65. */
delta = lr_used - stub_entry->group->lr_restore;
stub_entry->group->eh_size += eh_advance_size (delta) + 6;
stub_entry->group->lr_restore = lr_used + 8;
}
/* If the branch can't reach, use a plt_branch. */
if (off + (1 << 25) >= (bfd_vma) (1 << 26))
@@ -11455,6 +11685,7 @@ ppc_size_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
plt = htab->pltlocal;
}
targ += plt->output_offset + plt->output_section->vma;
odd = off & 4;
off = targ - off;
if (htab->params->plt_stub_align != 0)
@@ -11468,24 +11699,31 @@ ppc_size_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
if (info->emitrelocations)
{
stub_entry->group->stub_sec->reloc_count
+= num_relocs_for_offset (off - 8);
unsigned int num_rel;
if (htab->powerxx_stubs)
num_rel = num_relocs_for_powerxx_offset (off, odd);
else
num_rel = num_relocs_for_offset (off - 8);
stub_entry->group->stub_sec->reloc_count += num_rel;
stub_entry->group->stub_sec->flags |= SEC_RELOC;
}
size = plt_stub_size (htab, stub_entry, off);
/* After the bcl, lr has been modified so we need to emit
.eh_frame info saying the return address is in r12. */
lr_used = stub_entry->stub_offset + 8;
if (stub_entry->stub_type == ppc_stub_plt_call_both)
lr_used += 4;
/* The eh_frame info will consist of a DW_CFA_advance_loc or
variant, DW_CFA_register, 65, 12, DW_CFA_advance_loc+2,
DW_CFA_restore_extended 65. */
delta = lr_used - stub_entry->group->lr_restore;
stub_entry->group->eh_size += eh_advance_size (delta) + 6;
stub_entry->group->lr_restore = lr_used + 8;
if (!htab->powerxx_stubs)
{
/* After the bcl, lr has been modified so we need to emit
.eh_frame info saying the return address is in r12. */
lr_used = stub_entry->stub_offset + 8;
if (stub_entry->stub_type == ppc_stub_plt_call_both)
lr_used += 4;
/* The eh_frame info will consist of a DW_CFA_advance_loc or
variant, DW_CFA_register, 65, 12, DW_CFA_advance_loc+2,
DW_CFA_restore_extended 65. */
delta = lr_used - stub_entry->group->lr_restore;
stub_entry->group->eh_size += eh_advance_size (delta) + 6;
stub_entry->group->lr_restore = lr_used + 8;
}
break;
case ppc_stub_plt_call:
ld/ChangeLog
+6
View File
@@ -1,3 +1,9 @@
2019-05-24 Alan Modra <amodra@gmail.com>
* testsuite/ld-powerpc/notoc2.d,
* testsuite/ld-powerpc/notoc2.s: New test.
* testsuite/ld-powerpc/powerpc.exp: Run it.
2019-05-24 Alan Modra <amodra@gmail.com>
* testsuite/ld-powerpc/pcrelopt.s,
ld/testsuite/ld-powerpc/notoc2.d
+29
View File
@@ -0,0 +1,29 @@
#source: notoc2.s
#as: -a64 -mfuture
#ld: -shared -z norelro
#objdump: -d -Mfuture
#target: powerpc64*-*-*
.*
Disassembly of section \.text:
.* <.*\.plt_call\.puts>:
.*: (04 10 00 01|01 00 10 04) pld r12,66200
.*: (e5 80 02 98|98 02 80 e5)
.*: (7d 89 03 a6|a6 03 89 7d) mtctr r12
.*: (4e 80 04 20|20 04 80 4e) bctr
#...
.*: (04 13 ff ff|ff ff 13 04) pld r12,-1
.*: (e5 80 ff ff|ff ff 80 e5)
.*: (04 10 00 00|00 00 10 04) pld r12,0
.*: (e5 80 00 00|00 00 80 e5)
.*: (06 13 ff ff|ff ff 13 06) pla r12,-1
.*: (39 80 ff ff|ff ff 80 39)
.*: (06 10 00 00|00 00 10 06) pla r12,0
.*: (39 80 00 00|00 00 80 39)
.*: (06 10 00 00|00 00 10 06) pla r3,92
.*: (38 60 00 5c|5c 00 60 38)
.*: (4b ff ff 99|99 ff ff 4b) bl .* <.*\.plt_call\.puts>
.*: (60 00 00 00|00 00 00 60) nop
#pass
ld/testsuite/ld-powerpc/notoc2.s
+13
View File
@@ -0,0 +1,13 @@
.text
.weak puts
pld 12,-1(0),1
pld 12,0(0),1
paddi 12,0,-1,1
paddi 12,0,0,1
0:
paddi 3,0,hello-.,1
bl puts@notoc
nop
b 0b
.section .rodata
hello: .asciz "Hello!"
ld/testsuite/ld-powerpc/powerpc.exp
+2
View File
@@ -260,6 +260,8 @@ set ppc64elftests {
{"notoc ext" "" "" "-a64" {ext.s} {} ""}
{"notoc" "-melf64ppc --no-plt-localentry -T ext.lnk" "" "-a64" {notoc.s}
{{objdump -d notoc.d} {readelf {-wf -W} notoc.wf}} "notoc"}
{"notoc2" "-melf64ppc -shared" "" "-a64 -mfuture" {notoc2.s}
{{objdump {-d -Mfuture} notoc2.d}} "notoc2"}
{"pcrelopt" "-melf64ppc --hash-style=gnu" "tmpdir/symtocbase.so"
"-a64 -mfuture" {pcrelopt.s}
{{objdump {-d -Mfuture} pcrelopt.d}