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Re: ARM long branch stubs: shared libs
Hi all,
Here is an updated version of the patch, which now takes care of undef
weak references too.
Christophe.
2009-04-15 Christophe Lyon <christophe.lyon@st.com>
bfd/
* elf32-arm.c (elf32_arm_size_stubs): Handle long branches through
PLT entries to an undefined symbol when generating a shared
library.
testsuite/
* ld-arm/arm-elf.exp: Add new test farcall-mixed-lib.
* ld-arm/farcall-mixed-lib.d: Update expected output.
* ld-arm/farcall-mixed-lib1.s: New file.
* ld-arm/farcall-mixed-lib2.s: New file.
Index: bfd/elf32-arm.c
===================================================================
RCS file: /cvs/src/src/bfd/elf32-arm.c,v
retrieving revision 1.186
diff -u -p -r1.186 elf32-arm.c
--- bfd/elf32-arm.c 15 Apr 2009 13:49:54 -0000 1.186
+++ bfd/elf32-arm.c 15 Apr 2009 15:40:49 -0000
@@ -3832,12 +3832,29 @@ elf32_arm_size_stubs (bfd *output_bfd,
+ sym_sec->output_offset
+ sym_sec->output_section->vma);
}
- else if (hash->root.root.type == bfd_link_hash_undefweak
- || hash->root.root.type == bfd_link_hash_undefined)
- /* For a shared library, these will need a PLT stub,
- which is treated separately.
- For absolute code, they cannot be handled. */
- continue;
+ else if ((hash->root.root.type == bfd_link_hash_undefined)
+ || (hash->root.root.type == bfd_link_hash_undefweak))
+ {
+ /* For a shared library, use the PLT stub as
+ target address to decide whether a long
+ branch stub is needed.
+ For absolute code, they cannot be handled. */
+ struct elf32_arm_link_hash_table *globals =
+ elf32_arm_hash_table (info);
+
+ if (globals->splt != NULL && hash != NULL
+ && hash->root.plt.offset != (bfd_vma) -1)
+ {
+ sym_sec = globals->splt;
+ sym_value = hash->root.plt.offset;
+ if (sym_sec->output_section != NULL)
+ destination = (sym_value
+ + sym_sec->output_offset
+ + sym_sec->output_section->vma);
+ }
+ else
+ continue;
+ }
else
{
bfd_set_error (bfd_error_bad_value);
Index: ld/testsuite/ld-arm/arm-elf.exp
===================================================================
RCS file: /cvs/src/src/ld/testsuite/ld-arm/arm-elf.exp,v
retrieving revision 1.53
diff -u -p -r1.53 arm-elf.exp
--- ld/testsuite/ld-arm/arm-elf.exp 15 Apr 2009 13:49:54 -0000 1.53
+++ ld/testsuite/ld-arm/arm-elf.exp 15 Apr 2009 15:40:54 -0000
@@ -353,6 +353,12 @@ set armeabitests {
{{objdump -fdw farcall-mixed-app-v5.d} {objdump -Rw farcall-mixed-app.r}
{readelf -Ds farcall-mixed-app.sym}}
"farcall-mixed-app-v5"}
+
+ {"Mixed ARM/Thumb shared library with long branches" "-shared -T arm-lib.ld" ""
+ {farcall-mixed-lib1.s farcall-mixed-lib2.s}
+ {{objdump -fdw farcall-mixed-lib.d}}
+ "farcall-mixed-lib.so"}
+
}
run_ld_link_tests $armeabitests
Index: ld/testsuite/ld-arm/farcall-mixed-lib.d
===================================================================
RCS file: /cvs/src/src/ld/testsuite/ld-arm/farcall-mixed-lib.d,v
retrieving revision 1.1
diff -u -p -r1.1 farcall-mixed-lib.d
--- ld/testsuite/ld-arm/farcall-mixed-lib.d 5 Mar 2009 17:28:21 -0000 1.1
+++ ld/testsuite/ld-arm/farcall-mixed-lib.d 15 Apr 2009 15:40:54 -0000
@@ -14,24 +14,56 @@ Disassembly of section .plt:
.*: e28fc6.* add ip, pc, #.* ; 0x.*
.*: e28cca.* add ip, ip, #.* ; 0x.*
.*: e5bcf.* ldr pc, \[ip, #.*\]!
+ .*: e28fc6.* add ip, pc, #.* ; 0x.*
+ .*: e28cca.* add ip, ip, #.* ; 0x.*
+ .*: e5bcf.* ldr pc, \[ip, #.*\]!
Disassembly of section .text:
.* <lib_func1>:
.*: e1a0c00d mov ip, sp
.*: e92dd800 push {fp, ip, lr, pc}
.*: ebfffff. bl .* <lib_func1-0x..?>
+ .*: ebfffff. bl .* <lib_func1-0x..?>
.*: e89d6800 ldm sp, {fp, sp, lr}
.*: e12fff1e bx lr
- .*: e1a00000 nop \(mov r0,r0\)
- .*: e1a00000 nop \(mov r0,r0\)
- .*: e1a00000 nop \(mov r0,r0\)
+ ...
+ .*: e1a00000 .word 0xe1a00000
+ .*: e1a00000 .word 0xe1a00000
.* <lib_func2>:
+ .*: f000 e80c blx 100030c <__app_func_from_thumb>
+ .*: f000 e804 blx 1000300 <__app_func_weak_from_thumb>
.*: 4770 bx lr
.*: 46c0 nop \(mov r8, r8\)
.*: 46c0 nop \(mov r8, r8\)
.*: 46c0 nop \(mov r8, r8\)
+
+.* <__app_func_weak_from_thumb>:
+ .*: e59fc000 ldr ip, \[pc, #0\] ; 1000308 <__app_func_weak_from_thumb\+0x8>
+ .*: e08ff00c add pc, pc, ip
+ .*: feffffb4 .word 0xfeffffb4
+
+.* <__app_func_from_thumb>:
+ .*: e59fc000 ldr ip, \[pc, #0\] ; 1000314 <__app_func_from_thumb\+0x8>
+ .*: e08ff00c add pc, pc, ip
+ .*: feffff9c .word 0xfeffff9c
+ ...
+
+.* <lib_func3>:
+ .*: f000 e80c blx 200033c <__app_func_from_thumb>
+ .*: f000 e804 blx 2000330 <__app_func_weak_from_thumb>
+ .*: 4770 bx lr
.*: 46c0 nop \(mov r8, r8\)
.*: 46c0 nop \(mov r8, r8\)
.*: 46c0 nop \(mov r8, r8\)
- .*: 46c0 nop \(mov r8, r8\)
+
+.* <__app_func_weak_from_thumb>:
+ .*: e59fc000 ldr ip, \[pc, #0\] ; 2000338 <__app_func_weak_from_thumb\+0x8>
+ .*: e08ff00c add pc, pc, ip
+ .*: fdffff84 .word 0xfdffff84
+
+.* <__app_func_from_thumb>:
+ .*: e59fc000 ldr ip, \[pc, #0\] ; 2000344 <__app_func_from_thumb\+0x8>
+ .*: e08ff00c add pc, pc, ip
+ .*: fdffff6c .word 0xfdffff6c
+ ...
Index: ld/testsuite/ld-arm/farcall-mixed-lib1.s
===================================================================
RCS file: ld/testsuite/ld-arm/farcall-mixed-lib1.s
diff -N ld/testsuite/ld-arm/farcall-mixed-lib1.s
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ ld/testsuite/ld-arm/farcall-mixed-lib1.s 15 Apr 2009 15:40:54 -0000
@@ -0,0 +1,31 @@
+@ Create a large shared library so that calls through PLT to an undef
+@ symbol require insertion of a long branch stub.
+@ Check also calls to an undef weak symbol.
+
+ .text
+ .arch armv5t
+
+ .p2align 4
+ .globl lib_func1
+ .type lib_func1, %function
+lib_func1:
+ mov ip, sp
+ stmdb sp!, {r11, ip, lr, pc}
+ bl app_func
+ .weak app_func_weak
+ bl app_func_weak
+ ldmia sp, {r11, sp, lr}
+ bx lr
+ .size lib_func1, . - lib_func1
+
+ .space 0x1000000
+ .p2align 4
+ .globl lib_func2
+ .type lib_func2, %function
+ .thumb_func
+ .code 16
+lib_func2:
+ bl app_func
+ bl app_func_weak
+ bx lr
+ .size lib_func2, . - lib_func2
Index: ld/testsuite/ld-arm/farcall-mixed-lib2.s
===================================================================
RCS file: ld/testsuite/ld-arm/farcall-mixed-lib2.s
diff -N ld/testsuite/ld-arm/farcall-mixed-lib2.s
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ ld/testsuite/ld-arm/farcall-mixed-lib2.s 15 Apr 2009 15:40:54 -0000
@@ -0,0 +1,19 @@
+@ Create a large shared library so that calls through PLT to an undef
+@ symbol require insertion of a long branch stub.
+@ Check also calls to an undef weak symbol.
+
+ .text
+ .arch armv5t
+
+ .space 0x1000000
+ .p2align 4
+ .globl lib_func3
+ .type lib_func3, %function
+ .thumb_func
+ .code 16
+lib_func3:
+ bl app_func
+ .weak app_func_weak
+ bl app_func_weak
+ bx lr
+ .size lib_func3, . - lib_func3