Optimize R_386_GOT32/R_386_GOT32X only if addend is 0

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.

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.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index ab717eae16e4854dab79d5f16938dd59e96a249c..e810dbe1c87a10c785b7bcec00f219e79df29722 100644 (file)
--- 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 ae3187dc3f7e546b371bbf34159ed444fb7d9e2d..300839b2794f01e6731b0f45824e6b2bd7ea4342 100644 (file)
--- 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 d7ef3c41d429c0ca3e3d8183ad96bc56529dc962..f0ca10591ab60d7bf018c577fb47aebb2a1ca370 100644 (file)
--- 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 a6601ed82295d1ea9b6b48ee54c4ed695cc30d12..fb1d3eafb6f8c9d175a25d81202f22c3f55eaa03 100644 (file)
--- 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 (file)
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 (file)
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 (file)
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 (file)
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 (file)
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 (file)
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 (file)
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 (file)
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 (file)
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 (file)
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 f0f47eb891ffe22dd1e74cf90183e5ff56ef2a3a..45b7f094ba1a01114f121b13478c5c780d42eb7c 100644 (file)
--- 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"