[ARM] Purecode compatible long branch veneer for M-profile targets with MOVW.

2016-07-05  Andre Vieria  <andre.simoesdiasvieira@arm.com>

	* elf32-arm.c (THUMB32_MOVT): New veneer macro.
	(THUMB32_MOVW): Likewise.
	(elf32_arm_stub_long_branch_thumb2_only_pure): New.
	(DEF_STUBS): Define long_branch_thumb2_only_pure.
	(arm_stub_is_thumb): Add new veneer stub.
	(arm_type_of_stub): Use new veneer.
	(arm_stub_required_alignment): Add new veneer.

2016-07-05  Andre Vieria  <andre.simoesdiasvieira@arm.com>

	* testsuite/ld-arm/farcall-thumb2-purecode.d: New test result.
	* testsuite/ld-arm/farcall-thumb2-purecode.s: New test.
	* testsuite/ld-arm/arm-elf.exp: Run it.
This commit is contained in:
Andre Vieria 2016-07-05 11:39:06 +01:00 committed by Richard Earnshaw
parent f0728ee368
commit d5a67c0290
6 changed files with 127 additions and 6 deletions

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@ -1,3 +1,13 @@
2016-07-05 Andre Vieria <andre.simoesdiasvieira@arm.com>
* elf32-arm.c (THUMB32_MOVT): New veneer macro.
(THUMB32_MOVW): Likewise.
(elf32_arm_stub_long_branch_thumb2_only_pure): New.
(DEF_STUBS): Define long_branch_thumb2_only_pure.
(arm_stub_is_thumb): Add new veneer stub.
(arm_type_of_stub): Use new veneer.
(arm_stub_required_alignment): Add new veneer.
2016-07-05 Andre Vieria <andre.simoesdiasvieira@arm.com>
* bfd-in2.h (SEC_ELF_NOREAD): Rename to ...

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@ -2360,6 +2360,8 @@ enum stub_insn_type
is inserted in arm_build_one_stub(). */
#define THUMB16_BCOND_INSN(X) {(X), THUMB16_TYPE, R_ARM_NONE, 1}
#define THUMB32_INSN(X) {(X), THUMB32_TYPE, R_ARM_NONE, 0}
#define THUMB32_MOVT(X) {(X), THUMB32_TYPE, R_ARM_THM_MOVT_ABS, 0}
#define THUMB32_MOVW(X) {(X), THUMB32_TYPE, R_ARM_THM_MOVW_ABS_NC, 0}
#define THUMB32_B_INSN(X, Z) {(X), THUMB32_TYPE, R_ARM_THM_JUMP24, (Z)}
#define ARM_INSN(X) {(X), ARM_TYPE, R_ARM_NONE, 0}
#define ARM_REL_INSN(X, Z) {(X), ARM_TYPE, R_ARM_JUMP24, (Z)}
@ -2409,6 +2411,15 @@ static const insn_sequence elf32_arm_stub_long_branch_thumb2_only[] =
DATA_WORD (0, R_ARM_ABS32, 0), /* dcd R_ARM_ABS32(x) */
};
/* Thumb -> Thumb long branch stub. Used for PureCode sections on Thumb2
M-profile architectures. */
static const insn_sequence elf32_arm_stub_long_branch_thumb2_only_pure[] =
{
THUMB32_MOVW (0xf2400c00), /* mov.w ip, R_ARM_MOVW_ABS_NC */
THUMB32_MOVT (0xf2c00c00), /* movt ip, R_ARM_MOVT_ABS << 16 */
THUMB16_INSN (0x4760), /* bx ip */
};
/* V4T Thumb -> Thumb long branch stub. Using the stack is not
allowed. */
static const insn_sequence elf32_arm_stub_long_branch_v4t_thumb_thumb[] =
@ -2634,6 +2645,7 @@ static const insn_sequence elf32_arm_stub_a8_veneer_blx[] =
DEF_STUB(a8_veneer_bl) \
DEF_STUB(a8_veneer_blx) \
DEF_STUB(long_branch_thumb2_only) \
DEF_STUB(long_branch_thumb2_only_pure)
#define DEF_STUB(x) arm_stub_##x,
enum elf32_arm_stub_type
@ -3808,6 +3820,7 @@ arm_stub_is_thumb (enum elf32_arm_stub_type stub_type)
{
case arm_stub_long_branch_thumb_only:
case arm_stub_long_branch_thumb2_only:
case arm_stub_long_branch_thumb2_only_pure:
case arm_stub_long_branch_v4t_thumb_arm:
case arm_stub_short_branch_v4t_thumb_arm:
case arm_stub_long_branch_v4t_thumb_arm_pic:
@ -3847,6 +3860,8 @@ arm_type_of_stub (struct bfd_link_info *info,
enum arm_st_branch_type branch_type = *actual_branch_type;
union gotplt_union *root_plt;
struct arm_plt_info *arm_plt;
int arch;
int thumb2_movw;
if (branch_type == ST_BRANCH_LONG)
return stub_type;
@ -3859,6 +3874,11 @@ arm_type_of_stub (struct bfd_link_info *info,
thumb2 = using_thumb2 (globals);
thumb2_bl = using_thumb2_bl (globals);
arch = bfd_elf_get_obj_attr_int (globals->obfd, OBJ_ATTR_PROC, Tag_CPU_arch);
/* True for architectures that implement the thumb2 movw instruction. */
thumb2_movw = thumb2 || (arch == TAG_CPU_ARCH_V8M_BASE);
/* Determine where the call point is. */
location = (input_sec->output_offset
+ input_sec->output_section->vma
@ -3945,6 +3965,15 @@ arm_type_of_stub (struct bfd_link_info *info,
/* Thumb to thumb. */
if (!thumb_only)
{
if (input_sec->flags & SEC_ELF_PURECODE)
(*_bfd_error_handler) (_("%B(%s): warning: long branch "
" veneers used in section with "
"SHF_ARM_PURECODE section "
"attribute is only supported"
" for M-profile targets that "
"implement the movw "
"instruction."));
stub_type = (bfd_link_pic (info) | globals->pic_veneer)
/* PIC stubs. */
? ((globals->use_blx
@ -3967,16 +3996,39 @@ arm_type_of_stub (struct bfd_link_info *info,
}
else
{
stub_type = (bfd_link_pic (info) | globals->pic_veneer)
/* PIC stub. */
? arm_stub_long_branch_thumb_only_pic
/* non-PIC stub. */
: (thumb2 ? arm_stub_long_branch_thumb2_only
: arm_stub_long_branch_thumb_only);
if (thumb2_movw && (input_sec->flags & SEC_ELF_PURECODE))
stub_type = arm_stub_long_branch_thumb2_only_pure;
else
{
if (input_sec->flags & SEC_ELF_PURECODE)
(*_bfd_error_handler) (_("%B(%s): warning: long branch "
" veneers used in section with "
"SHF_ARM_PURECODE section "
"attribute is only supported"
" for M-profile targets that "
"implement the movw "
"instruction."));
stub_type = (bfd_link_pic (info) | globals->pic_veneer)
/* PIC stub. */
? arm_stub_long_branch_thumb_only_pic
/* non-PIC stub. */
: (thumb2 ? arm_stub_long_branch_thumb2_only
: arm_stub_long_branch_thumb_only);
}
}
}
else
{
if (input_sec->flags & SEC_ELF_PURECODE)
(*_bfd_error_handler) (_("%B(%s): warning: long branch "
" veneers used in section with "
"SHF_ARM_PURECODE section "
"attribute is only supported"
" for M-profile targets that "
"implement the movw "
"instruction."));
/* Thumb to arm. */
if (sym_sec != NULL
&& sym_sec->owner != NULL
@ -4021,6 +4073,14 @@ arm_type_of_stub (struct bfd_link_info *info,
|| r_type == R_ARM_PLT32
|| r_type == R_ARM_TLS_CALL)
{
if (input_sec->flags & SEC_ELF_PURECODE)
(*_bfd_error_handler) (_("%B(%s): warning: long branch "
" veneers used in section with "
"SHF_ARM_PURECODE section "
"attribute is only supported"
" for M-profile targets that "
"implement the movw "
"instruction."));
if (branch_type == ST_BRANCH_TO_THUMB)
{
/* Arm to thumb. */
@ -4446,6 +4506,7 @@ arm_stub_required_alignment (enum elf32_arm_stub_type stub_type)
case arm_stub_long_branch_v4t_arm_thumb:
case arm_stub_long_branch_thumb_only:
case arm_stub_long_branch_thumb2_only:
case arm_stub_long_branch_thumb2_only_pure:
case arm_stub_long_branch_v4t_thumb_thumb:
case arm_stub_long_branch_v4t_thumb_arm:
case arm_stub_short_branch_v4t_thumb_arm:

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@ -1,3 +1,9 @@
2016-07-05 Andre Vieria <andre.simoesdiasvieira@arm.com>
* testsuite/ld-arm/farcall-thumb2-purecode.d: New test result.
* testsuite/ld-arm/farcall-thumb2-purecode.s: New test.
* testsuite/ld-arm/arm-elf.exp: Run it.
2016-07-05 Andre Vieria <andre.simoesdiasvieira@arm.com>
* testsuite/ld-arm/arm_noread.ld: Renamed to ...

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@ -505,6 +505,9 @@ set armeabitests_nonacl {
{farcall-thumb-thumb-m-no-profile-a.s farcall-thumb-thumb-m-no-profile-b.s}
{{objdump -d farcall-thumb-thumb-m-no-profile.d}}
"farcall-thumb-thumb-m-no-profile"}
{"Thumb2 purecode farcall" "-Ttext 0x1000 --section-start .foo=0x2001020" "" "" {farcall-thumb2-purecode.s}
{{objdump -d farcall-thumb2-purecode.d}}
"farcall-thumb2-purecode"}
{"Thumb-ARM farcall" "-Ttext 0x1c01010 --section-start .foo=0x2001014" "" "-W" {farcall-thumb-arm.s}
{{objdump -d farcall-thumb-arm.d}}

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@ -0,0 +1,22 @@
.*: file format .*
Disassembly of section .text:
00001000 <bar>:
1000: 4770 bx lr
Disassembly of section .foo:
02001020 <_start>:
2001020: f000 f802 bl 2001028 <__bar_veneer>
2001024: 0000 movs r0, r0
\.\.\.
02001028 <__bar_veneer>:
2001028: f241 0c01 movw ip, #4097 ; 0x1001
200102c: f2c0 0c00 movt ip, #0
2001030: 4760 bx ip
2001032: 0000 movs r0, r0
2001034: 0000 movs r0, r0
\.\.\.

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@ -0,0 +1,19 @@
@ Test to ensure that a purecode Thumb2 call exceeding 4Mb generates a stub.
.global _start
.syntax unified
.arch armv7-m
.thumb
.thumb_func
@ We will place the section .text at 0x1000.
.text
bar:
bx lr
@ We will place the section .foo at 0x02001014.
.section .foo, "0x20000006"
_start:
bl bar