glibc/sysdeps/unix/sysv/linux/arm/unwind-resume.c
Joseph Myers 175cef4163 Fix ARM build with GCC trunk.
sysdeps/unix/sysv/linux/arm/unwind-resume.c and
sysdeps/unix/sysv/linux/arm/unwind-forcedunwind.c have static
variables that are written in C code but only read from toplevel asms.
Current GCC trunk now optimizes away such apparently write-only static
variables, so causing a build failure.  This patch marks those
variables with __attribute_used__ to avoid that optimization.

Tested that this fixes the build for ARM.

	* sysdeps/unix/sysv/linux/arm/unwind-forcedunwind.c
	(libgcc_s_resume): Use __attribute_used__.
	* sysdeps/unix/sysv/linux/arm/unwind-resume.c (libgcc_s_resume):
	Likewise.
2014-05-20 21:27:13 +00:00

102 lines
3.0 KiB
C

/* Copyright (C) 2003-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek <jakub@redhat.com>.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
#include <dlfcn.h>
#include <stdio.h>
#include <unwind.h>
static void (*libgcc_s_resume) (struct _Unwind_Exception *exc)
__attribute_used__;
static _Unwind_Reason_Code (*libgcc_s_personality)
(_Unwind_State, struct _Unwind_Exception *, struct _Unwind_Context *);
static void init (void) __attribute_used__;
static void
init (void)
{
void *resume, *personality;
void *handle;
handle = __libc_dlopen ("libgcc_s.so.1");
if (handle == NULL
|| (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL
|| (personality = __libc_dlsym (handle, "__gcc_personality_v0")) == NULL)
__libc_fatal ("libgcc_s.so.1 must be installed for pthread_cancel to work\n");
libgcc_s_resume = resume;
libgcc_s_personality = personality;
}
/* It's vitally important that _Unwind_Resume not have a stack frame; the
ARM unwinder relies on register state at entrance. So we write this in
assembly. */
#define STR1(S) #S
#define STR(S) STR1(S)
asm (
" .globl _Unwind_Resume\n"
" .type _Unwind_Resume, %function\n"
"_Unwind_Resume:\n"
" .cfi_sections .debug_frame\n"
" " CFI_STARTPROC "\n"
" push {r4, r5, r6, lr}\n"
" " CFI_ADJUST_CFA_OFFSET (16)" \n"
" " CFI_REL_OFFSET (r4, 0) "\n"
" " CFI_REL_OFFSET (r5, 4) "\n"
" " CFI_REL_OFFSET (r6, 8) "\n"
" " CFI_REL_OFFSET (lr, 12) "\n"
" " CFI_REMEMBER_STATE "\n"
" ldr r4, 1f\n"
" ldr r5, 2f\n"
"3: add r4, pc, r4\n"
" ldr r3, [r4, r5]\n"
" mov r6, r0\n"
" cmp r3, #0\n"
" beq 4f\n"
"5: mov r0, r6\n"
" pop {r4, r5, r6, lr}\n"
" " CFI_ADJUST_CFA_OFFSET (-16) "\n"
" " CFI_RESTORE (r4) "\n"
" " CFI_RESTORE (r5) "\n"
" " CFI_RESTORE (r6) "\n"
" " CFI_RESTORE (lr) "\n"
" bx r3\n"
" " CFI_RESTORE_STATE "\n"
"4: bl init\n"
" ldr r3, [r4, r5]\n"
" b 5b\n"
" " CFI_ENDPROC "\n"
" .align 2\n"
"1: .word _GLOBAL_OFFSET_TABLE_ - 3b - " STR (PC_OFS) "\n"
"2: .word libgcc_s_resume(GOTOFF)\n"
" .size _Unwind_Resume, .-_Unwind_Resume\n"
);
_Unwind_Reason_Code
__gcc_personality_v0 (_Unwind_State state,
struct _Unwind_Exception *ue_header,
struct _Unwind_Context *context)
{
if (__builtin_expect (libgcc_s_personality == NULL, 0))
init ();
return libgcc_s_personality (state, ue_header, context);
}