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175cef4163
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.
159 lines
4.5 KiB
C
159 lines
4.5 KiB
C
/* Copyright (C) 2003-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Jakub Jelinek <jakub@redhat.com>.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#include <dlfcn.h>
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#include <stdio.h>
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#include <unwind.h>
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#include <pthreadP.h>
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static void *libgcc_s_handle;
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static void (*libgcc_s_resume) (struct _Unwind_Exception *exc)
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__attribute_used__;
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static _Unwind_Reason_Code (*libgcc_s_personality)
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(_Unwind_State, struct _Unwind_Exception *, struct _Unwind_Context *);
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static _Unwind_Reason_Code (*libgcc_s_forcedunwind)
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(struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
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static _Unwind_Word (*libgcc_s_getcfa) (struct _Unwind_Context *);
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void
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__attribute_noinline__
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pthread_cancel_init (void)
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{
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void *resume, *personality, *forcedunwind, *getcfa;
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void *handle;
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if (__builtin_expect (libgcc_s_handle != NULL, 1))
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{
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/* Force gcc to reload all values. */
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asm volatile ("" ::: "memory");
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return;
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}
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handle = __libc_dlopen ("libgcc_s.so.1");
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if (handle == NULL
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|| (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL
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|| (personality = __libc_dlsym (handle, "__gcc_personality_v0")) == NULL
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|| (forcedunwind = __libc_dlsym (handle, "_Unwind_ForcedUnwind"))
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== NULL
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|| (getcfa = __libc_dlsym (handle, "_Unwind_GetCFA")) == NULL
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#ifdef ARCH_CANCEL_INIT
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|| ARCH_CANCEL_INIT (handle)
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#endif
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)
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__libc_fatal ("libgcc_s.so.1 must be installed for pthread_cancel to work\n");
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libgcc_s_resume = resume;
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libgcc_s_personality = personality;
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libgcc_s_forcedunwind = forcedunwind;
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libgcc_s_getcfa = getcfa;
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/* Make sure libgcc_s_getcfa is written last. Otherwise,
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pthread_cancel_init might return early even when the pointer the
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caller is interested in is not initialized yet. */
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atomic_write_barrier ();
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libgcc_s_handle = handle;
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}
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void
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__libc_freeres_fn_section
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__unwind_freeres (void)
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{
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void *handle = libgcc_s_handle;
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if (handle != NULL)
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{
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libgcc_s_handle = NULL;
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__libc_dlclose (handle);
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}
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}
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/* It's vitally important that _Unwind_Resume not have a stack frame; the
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ARM unwinder relies on register state at entrance. So we write this in
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assembly. */
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#define STR1(S) #S
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#define STR(S) STR1(S)
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asm (
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" .globl _Unwind_Resume\n"
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" .type _Unwind_Resume, %function\n"
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"_Unwind_Resume:\n"
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" .cfi_sections .debug_frame\n"
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" " CFI_STARTPROC "\n"
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" push {r4, r5, r6, lr}\n"
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" " CFI_ADJUST_CFA_OFFSET (16)" \n"
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" " CFI_REL_OFFSET (r4, 0) "\n"
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" " CFI_REL_OFFSET (r5, 4) "\n"
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" " CFI_REL_OFFSET (r6, 8) "\n"
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" " CFI_REL_OFFSET (lr, 12) "\n"
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" " CFI_REMEMBER_STATE "\n"
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" ldr r4, 1f\n"
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" ldr r5, 2f\n"
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"3: add r4, pc, r4\n"
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" ldr r3, [r4, r5]\n"
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" mov r6, r0\n"
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" cmp r3, #0\n"
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" beq 4f\n"
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"5: mov r0, r6\n"
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" pop {r4, r5, r6, lr}\n"
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" " CFI_ADJUST_CFA_OFFSET (-16) "\n"
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" " CFI_RESTORE (r4) "\n"
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" " CFI_RESTORE (r5) "\n"
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" " CFI_RESTORE (r6) "\n"
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" " CFI_RESTORE (lr) "\n"
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" bx r3\n"
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" " CFI_RESTORE_STATE "\n"
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"4: bl pthread_cancel_init\n"
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" ldr r3, [r4, r5]\n"
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" b 5b\n"
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" " CFI_ENDPROC "\n"
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" .align 2\n"
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"1: .word _GLOBAL_OFFSET_TABLE_ - 3b - " STR (PC_OFS) "\n"
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"2: .word libgcc_s_resume(GOTOFF)\n"
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" .size _Unwind_Resume, .-_Unwind_Resume\n"
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);
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_Unwind_Reason_Code
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__gcc_personality_v0 (_Unwind_State state,
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struct _Unwind_Exception *ue_header,
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struct _Unwind_Context *context)
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{
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if (__builtin_expect (libgcc_s_personality == NULL, 0))
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pthread_cancel_init ();
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return libgcc_s_personality (state, ue_header, context);
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}
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_Unwind_Reason_Code
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_Unwind_ForcedUnwind (struct _Unwind_Exception *exc, _Unwind_Stop_Fn stop,
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void *stop_argument)
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{
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if (__builtin_expect (libgcc_s_forcedunwind == NULL, 0))
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pthread_cancel_init ();
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return libgcc_s_forcedunwind (exc, stop, stop_argument);
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}
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_Unwind_Word
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_Unwind_GetCFA (struct _Unwind_Context *context)
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{
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if (__builtin_expect (libgcc_s_getcfa == NULL, 0))
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pthread_cancel_init ();
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return libgcc_s_getcfa (context);
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}
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