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[PATCH, committed][2.26] Optimize R_386_GOT32/R_386_GOT32X only if addend is 0
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Binutils <binutils at sourceware dot org>
- Date: Sat, 5 Dec 2015 08:39:33 -0800
- Subject: [PATCH, committed][2.26] Optimize R_386_GOT32/R_386_GOT32X only if addend is 0
- Authentication-results: sourceware.org; auth=none
Checked into 2.26 branch.
H.J.
On Fri, Dec 4, 2015 at 9:12 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> Linker can't optimize R_386_GOT32 and R_386_GOT32X relocations if addend
> isn't 0. It isn't valid to convert
>
> movl foo@GOT+1(%ecx), %eax
>
> to
>
> leal foo@GOTOFF+1(%ecx), %eax
>
> nor to convert
>
> movq foo@GOTPCREL+1(%rip), %rax
>
> to
>
> leaq foo(%rip), %rax
>
> for x86-64. We should check if addend is 0 before optimizing R_386_GOT32
> and R_386_GOT32X relocations. Testcases are added for i386 and x86-64.
>
> Checked into master. I will backport it to 2.26 branch later.
>
> H.J.
> ---
> bfd/
>
> * elf32-i386.c (elf_i386_convert_load): Skip if addend isn't 0.
> (elf_i386_relocate_section): Skip R_386_GOT32X optimization if
> addend isn't 0.
>
> ld/testsuite/
>
> * ld-i386/i386.exp: Run mov2a, mov2b and mov3.
> * ld-i386/mov2.s: New file.
> * ld-i386/mov2a.d: Likewise.
> * ld-i386/mov2b.d: Likewise.
> * ld-i386/mov3.d: Likewise.
> * ld-i386/mov3.s: Likewise.
> * ld-x86-64/mov2.s: Likewise.
> * ld-x86-64/mov2a.d: Likewise.
> * ld-x86-64/mov2b.d: Likewise.
> * ld-x86-64/mov2c.d: Likewise.
> * ld-x86-64/mov2d.d: Likewise.
> * ld-x86-64/x86-64.exp: Run mov2a, mov2b, mov2c and mov2d.
> ---
> bfd/ChangeLog | 6 ++++++
> bfd/elf32-i386.c | 24 +++++++++++-------------
> ld/testsuite/ChangeLog | 13 +++++++++++++
> ld/testsuite/ld-i386/i386.exp | 3 +++
> ld/testsuite/ld-i386/mov2.s | 15 +++++++++++++++
> ld/testsuite/ld-i386/mov2a.d | 15 +++++++++++++++
> ld/testsuite/ld-i386/mov2b.d | 15 +++++++++++++++
> ld/testsuite/ld-i386/mov3.d | 14 ++++++++++++++
> ld/testsuite/ld-i386/mov3.s | 15 +++++++++++++++
> ld/testsuite/ld-x86-64/mov2.s | 15 +++++++++++++++
> ld/testsuite/ld-x86-64/mov2a.d | 15 +++++++++++++++
> ld/testsuite/ld-x86-64/mov2b.d | 15 +++++++++++++++
> ld/testsuite/ld-x86-64/mov2c.d | 15 +++++++++++++++
> ld/testsuite/ld-x86-64/mov2d.d | 15 +++++++++++++++
> ld/testsuite/ld-x86-64/x86-64.exp | 4 ++++
> 15 files changed, 186 insertions(+), 13 deletions(-)
> create mode 100644 ld/testsuite/ld-i386/mov2.s
> create mode 100644 ld/testsuite/ld-i386/mov2a.d
> create mode 100644 ld/testsuite/ld-i386/mov2b.d
> create mode 100644 ld/testsuite/ld-i386/mov3.d
> create mode 100644 ld/testsuite/ld-i386/mov3.s
> create mode 100644 ld/testsuite/ld-x86-64/mov2.s
> create mode 100644 ld/testsuite/ld-x86-64/mov2a.d
> create mode 100644 ld/testsuite/ld-x86-64/mov2b.d
> create mode 100644 ld/testsuite/ld-x86-64/mov2c.d
> create mode 100644 ld/testsuite/ld-x86-64/mov2d.d
>
> diff --git a/bfd/ChangeLog b/bfd/ChangeLog
> index ab717ea..e810dbe 100644
> --- a/bfd/ChangeLog
> +++ b/bfd/ChangeLog
> @@ -1,3 +1,9 @@
> +2015-12-04 H.J. Lu <hongjiu.lu@intel.com>
> +
> + * elf32-i386.c (elf_i386_convert_load): Skip if addend isn't 0.
> + (elf_i386_relocate_section): Skip R_386_GOT32X optimization if
> + addend isn't 0.
> +
> 2015-12-04 Tristan Gingold <gingold@adacore.com>
>
> * elf.c (rewrite_elf_program_header): Remove useless loop.
> diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
> index ae3187d..300839b 100644
> --- a/bfd/elf32-i386.c
> +++ b/bfd/elf32-i386.c
> @@ -2820,6 +2820,11 @@ elf_i386_convert_load (bfd *abfd, asection *sec,
> if (roff < 2)
> continue;
>
> + /* Addend for R_386_GOT32 and R_386_GOT32X relocations must be 0. */
> + addend = bfd_get_32 (abfd, contents + roff);
> + if (addend != 0)
> + continue;
> +
> modrm = bfd_get_8 (abfd, contents + roff - 1);
> baseless = (modrm & 0xc7) == 0x5;
>
> @@ -2913,11 +2918,6 @@ elf_i386_convert_load (bfd *abfd, asection *sec,
> {
> /* The function is locally defined. */
> convert_branch:
> - addend = bfd_get_32 (abfd, contents + roff);
> - /* Addend for R_386_GOT32X relocation must be 0. */
> - if (addend != 0)
> - continue;
> -
> /* Convert R_386_GOT32X to R_386_PC32. */
> if (modrm == 0x15 || (modrm & 0xf8) == 0x90)
> {
> @@ -3007,11 +3007,6 @@ convert_load:
> }
> else
> {
> - /* Addend for R_386_GOT32X relocation must be 0. */
> - addend = bfd_get_32 (abfd, contents + roff);
> - if (addend != 0)
> - continue;
> -
> if (opcode == 0x85)
> {
> /* Convert "test %reg1, foo@GOT(%reg2)" to
> @@ -3998,8 +3993,11 @@ elf_i386_relocate_section (bfd *output_bfd,
> branch to direct branch. It is OK to convert adc,
> add, and, cmp, or, sbb, sub, test, xor only when PIC
> is false. */
> - unsigned int opcode;
> - opcode = bfd_get_8 (abfd, contents + rel->r_offset - 2);
> + unsigned int opcode, addend;
> + addend = bfd_get_32 (input_bfd, contents + rel->r_offset);
> + if (addend != 0)
> + goto r_386_got32;
> + opcode = bfd_get_8 (input_bfd, contents + rel->r_offset - 2);
> if (opcode != 0x8b && opcode != 0xff)
> goto r_386_got32;
> }
> @@ -4031,7 +4029,7 @@ elf_i386_relocate_section (bfd *output_bfd,
> /* If not PIC, add the .got.plt section address for
> baseless addressing. */
> unsigned int modrm;
> - modrm = bfd_get_8 (abfd, contents + rel->r_offset - 1);
> + modrm = bfd_get_8 (input_bfd, contents + rel->r_offset - 1);
> if ((modrm & 0xc7) == 0x5)
> relocation += offplt;
> }
> diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
> index d7ef3c4..f0ca105 100644
> --- a/ld/testsuite/ChangeLog
> +++ b/ld/testsuite/ChangeLog
> @@ -1,3 +1,16 @@
> +2015-12-04 H.J. Lu <hongjiu.lu@intel.com>
> +
> + * ld-i386/i386.exp: Run mov2a and mov2b.
> + * ld-i386/mov2.s: New file.
> + * ld-i386/mov2a.d: Likewise.
> + * ld-i386/mov2b.d: Likewise.
> + * ld-x86-64/mov2.s: Likewise.
> + * ld-x86-64/mov2a.d: Likewise.
> + * ld-x86-64/mov2b.d: Likewise.
> + * ld-x86-64/mov2c.d: Likewise.
> + * ld-x86-64/mov2d.d: Likewise.
> + * ld-x86-64/x86-64.exp: Run mov2a, mov2b, mov2c and mov2d.
> +
> 2015-12-01 H.J. Lu <hongjiu.lu@intel.com>
>
> PR ld/19319
> diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp
> index a6601ed..fb1d3ea 100644
> --- a/ld/testsuite/ld-i386/i386.exp
> +++ b/ld/testsuite/ld-i386/i386.exp
> @@ -293,6 +293,9 @@ run_dump_test "lea1e"
> run_dump_test "lea1f"
> run_dump_test "mov1a"
> run_dump_test "mov1b"
> +run_dump_test "mov2a"
> +run_dump_test "mov2b"
> +run_dump_test "mov3"
> run_dump_test "branch1"
> run_dump_test "call1"
> run_dump_test "call2"
> diff --git a/ld/testsuite/ld-i386/mov2.s b/ld/testsuite/ld-i386/mov2.s
> new file mode 100644
> index 0000000..3fa06ce
> --- /dev/null
> +++ b/ld/testsuite/ld-i386/mov2.s
> @@ -0,0 +1,15 @@
> + .section my_section,"aw",@progbits
> + .long 0x12345678
> + .text
> + .globl foo
> + .type foo, @function
> +foo:
> + ret
> + .size foo, .-foo
> + .globl _start
> + .type _start, @function
> +_start:
> + movl foo@GOT+1(%ecx), %eax
> + movl __start_my_section@GOT+1(%ecx), %eax
> + movl __stop_my_section@GOT+1(%ecx), %eax
> + .size _start, .-_start
> diff --git a/ld/testsuite/ld-i386/mov2a.d b/ld/testsuite/ld-i386/mov2a.d
> new file mode 100644
> index 0000000..d8756e5
> --- /dev/null
> +++ b/ld/testsuite/ld-i386/mov2a.d
> @@ -0,0 +1,15 @@
> +#source: mov2.s
> +#as: --32
> +#ld: -shared -melf_i386
> +#objdump: -dw
> +
> +.*: +file format .*
> +
> +
> +Disassembly of section .text:
> +
> +#...
> +[ ]*[a-f0-9]+: 8b 81 ([0-9a-f]{2} ){4} * mov -0x[a-f0-9]+\(%ecx\),%eax
> +[ ]*[a-f0-9]+: 8b 81 ([0-9a-f]{2} ){4} * mov -0x[a-f0-9]+\(%ecx\),%eax
> +[ ]*[a-f0-9]+: 8b 81 ([0-9a-f]{2} ){4} * mov -0x[a-f0-9]+\(%ecx\),%eax
> +#pass
> diff --git a/ld/testsuite/ld-i386/mov2b.d b/ld/testsuite/ld-i386/mov2b.d
> new file mode 100644
> index 0000000..ea5dd9b
> --- /dev/null
> +++ b/ld/testsuite/ld-i386/mov2b.d
> @@ -0,0 +1,15 @@
> +#source: mov2.s
> +#as: --32
> +#ld: -pie -melf_i386
> +#objdump: -dw
> +
> +.*: +file format .*
> +
> +
> +Disassembly of section .text:
> +
> +#...
> +[ ]*[a-f0-9]+: 8b 81 ([0-9a-f]{2} ){4} * mov -0x[a-f0-9]+\(%ecx\),%eax
> +[ ]*[a-f0-9]+: 8b 81 ([0-9a-f]{2} ){4} * mov -0x[a-f0-9]+\(%ecx\),%eax
> +[ ]*[a-f0-9]+: 8b 81 ([0-9a-f]{2} ){4} * mov -0x[a-f0-9]+\(%ecx\),%eax
> +#pass
> diff --git a/ld/testsuite/ld-i386/mov3.d b/ld/testsuite/ld-i386/mov3.d
> new file mode 100644
> index 0000000..17da244
> --- /dev/null
> +++ b/ld/testsuite/ld-i386/mov3.d
> @@ -0,0 +1,14 @@
> +#as: --32
> +#ld: -melf_i386
> +#objdump: -dw
> +
> +.*: +file format .*
> +
> +
> +Disassembly of section .text:
> +
> +#...
> +[ ]*[a-f0-9]+: 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\,%eax
> +[ ]*[a-f0-9]+: 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\,%eax
> +[ ]*[a-f0-9]+: 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\,%eax
> +#pass
> diff --git a/ld/testsuite/ld-i386/mov3.s b/ld/testsuite/ld-i386/mov3.s
> new file mode 100644
> index 0000000..0dc54eb
> --- /dev/null
> +++ b/ld/testsuite/ld-i386/mov3.s
> @@ -0,0 +1,15 @@
> + .section my_section,"aw",@progbits
> + .long 0x12345678
> + .text
> + .globl foo
> + .type foo, @function
> +foo:
> + ret
> + .size foo, .-foo
> + .globl _start
> + .type _start, @function
> +_start:
> + movl foo@GOT+1, %eax
> + movl __start_my_section@GOT+1, %eax
> + movl __stop_my_section@GOT+1, %eax
> + .size _start, .-_start
> diff --git a/ld/testsuite/ld-x86-64/mov2.s b/ld/testsuite/ld-x86-64/mov2.s
> new file mode 100644
> index 0000000..95e474f
> --- /dev/null
> +++ b/ld/testsuite/ld-x86-64/mov2.s
> @@ -0,0 +1,15 @@
> + .section my_section,"aw",@progbits
> + .long 0x12345678
> + .text
> + .globl foo
> + .type foo, @function
> +foo:
> + ret
> + .size foo, .-foo
> + .globl _start
> + .type _start, @function
> +_start:
> + movq foo@GOTPCREL+1(%rip), %rax
> + movq __start_my_section@GOTPCREL+1(%rip), %rax
> + movq __stop_my_section@GOTPCREL+1(%rip), %rax
> + .size _start, .-_start
> diff --git a/ld/testsuite/ld-x86-64/mov2a.d b/ld/testsuite/ld-x86-64/mov2a.d
> new file mode 100644
> index 0000000..aaf5707
> --- /dev/null
> +++ b/ld/testsuite/ld-x86-64/mov2a.d
> @@ -0,0 +1,15 @@
> +#source: mov2.s
> +#as: --64
> +#ld: -shared -melf_x86_64
> +#objdump: -dw
> +
> +.*: +file format .*
> +
> +
> +Disassembly of section .text:
> +
> +#...
> +[ ]*[a-f0-9]+: 48 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
> +[ ]*[a-f0-9]+: 48 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
> +[ ]*[a-f0-9]+: 48 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
> +#pass
> diff --git a/ld/testsuite/ld-x86-64/mov2b.d b/ld/testsuite/ld-x86-64/mov2b.d
> new file mode 100644
> index 0000000..ee1b308
> --- /dev/null
> +++ b/ld/testsuite/ld-x86-64/mov2b.d
> @@ -0,0 +1,15 @@
> +#source: mov2.s
> +#as: --64
> +#ld: -pie -melf_x86_64
> +#objdump: -dw
> +
> +.*: +file format .*
> +
> +
> +Disassembly of section .text:
> +
> +#...
> +[ ]*[a-f0-9]+: 48 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
> +[ ]*[a-f0-9]+: 48 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
> +[ ]*[a-f0-9]+: 48 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
> +#pass
> diff --git a/ld/testsuite/ld-x86-64/mov2c.d b/ld/testsuite/ld-x86-64/mov2c.d
> new file mode 100644
> index 0000000..8991121
> --- /dev/null
> +++ b/ld/testsuite/ld-x86-64/mov2c.d
> @@ -0,0 +1,15 @@
> +#source: mov2.s
> +#as: --x32
> +#ld: -shared -melf32_x86_64
> +#objdump: -dw
> +
> +.*: +file format .*
> +
> +
> +Disassembly of section .text:
> +
> +#...
> +[ ]*[a-f0-9]+: 48 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
> +[ ]*[a-f0-9]+: 48 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
> +[ ]*[a-f0-9]+: 48 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
> +#pass
> diff --git a/ld/testsuite/ld-x86-64/mov2d.d b/ld/testsuite/ld-x86-64/mov2d.d
> new file mode 100644
> index 0000000..744028e
> --- /dev/null
> +++ b/ld/testsuite/ld-x86-64/mov2d.d
> @@ -0,0 +1,15 @@
> +#source: mov2.s
> +#as: --x32
> +#ld: -pie -melf32_x86_64
> +#objdump: -dw
> +
> +.*: +file format .*
> +
> +
> +Disassembly of section .text:
> +
> +#...
> +[ ]*[a-f0-9]+: 48 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
> +[ ]*[a-f0-9]+: 48 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
> +[ ]*[a-f0-9]+: 48 8b 05 ([0-9a-f]{2} ){4} * mov 0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <_DYNAMIC\+0x[a-f0-9]+>
> +#pass
> diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
> index f0f47eb..45b7f09 100644
> --- a/ld/testsuite/ld-x86-64/x86-64.exp
> +++ b/ld/testsuite/ld-x86-64/x86-64.exp
> @@ -321,6 +321,10 @@ run_dump_test "mov1a"
> run_dump_test "mov1b"
> run_dump_test "mov1c"
> run_dump_test "mov1d"
> +run_dump_test "mov2a"
> +run_dump_test "mov2b"
> +run_dump_test "mov2c"
> +run_dump_test "mov2d"
> run_dump_test "load1a"
> run_dump_test "load1b"
> run_dump_test "load1c"
> --
> 2.5.0
>
--
H.J.