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55668624cf
For arm this makes no difference--the result is bit-for-bit identical; for thumb this results in smaller encodings. Perhaps it ought not and this is in fact an assembler bug, but I also think it's clearer.
211 lines
5.3 KiB
ArmAsm
211 lines
5.3 KiB
ArmAsm
/* Thread-local storage handling in the ELF dynamic linker. ARM version.
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Copyright (C) 2006-2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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
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License as published by the Free Software Foundation; either
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version 2.1 of the 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 <sysdep.h>
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#include <tls.h>
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#include "tlsdesc.h"
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#ifdef __USE_BX__
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#define BX(x) bx x
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#else
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#define BX(x) mov pc, x
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#endif
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.text
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@ emit debug information with cfi
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@ use arm-specific pseudos for unwinding itself
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CFI_SECTIONS
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.hidden _dl_tlsdesc_return
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.global _dl_tlsdesc_return
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.type _dl_tlsdesc_return,#function
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cfi_startproc
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.fnstart
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.align 2
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_dl_tlsdesc_return:
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ldr r0, [r0]
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BX (lr)
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.fnend
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cfi_endproc
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.size _dl_tlsdesc_return, .-_dl_tlsdesc_return
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.hidden _dl_tlsdesc_undefweak
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.global _dl_tlsdesc_undefweak
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.type _dl_tlsdesc_undefweak,#function
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cfi_startproc
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.fnstart
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.align 2
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_dl_tlsdesc_undefweak:
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GET_TLS (r1)
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rsb r0, r0, #0
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BX (lr)
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cfi_endproc
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.fnend
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.size _dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak
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#ifdef SHARED
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.hidden _dl_tlsdesc_dynamic
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.global _dl_tlsdesc_dynamic
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.type _dl_tlsdesc_dynamic,#function
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/*
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The assembly code that follows is a rendition of the following
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C code, hand-optimized a little bit.
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ptrdiff_t
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_dl_tlsdesc_dynamic(struct tlsdesc *tdp)
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{
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struct tlsdesc_dynamic_arg *td = tdp->argument.pointer;
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dtv_t *dtv = (dtv_t *)THREAD_DTV();
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if (__builtin_expect (td->gen_count <= dtv[0].counter
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&& dtv[td->tlsinfo.ti_module].pointer.val
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!= TLS_DTV_UNALLOCATED,
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1))
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return dtv[td->tlsinfo.ti_module].pointer.val +
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td->tlsinfo.ti_offset - __builtin_thread_pointer();
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return __tls_get_addr (&td->tlsinfo) - __builtin_thread_pointer();
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}
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*/
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cfi_startproc
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.fnstart
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.align 2
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_dl_tlsdesc_dynamic:
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/* Our calling convention is to clobber r0, r1 and the processor
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flags. All others that are modified must be saved */
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.save {r2,r3,r4,lr}
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push {r2,r3,r4,lr}
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cfi_adjust_cfa_offset (16)
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cfi_rel_offset (r2,0)
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cfi_rel_offset (r3,4)
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cfi_rel_offset (r4,8)
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cfi_rel_offset (lr,12)
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ldr r1, [r0] /* td */
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GET_TLS (lr)
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mov r4, r0 /* r4 = tp */
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ldr r0, [r0]
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ldr r2, [r1, #8] /* gen_count */
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ldr r3, [r0]
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cmp r2, r3
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bhi 1f
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ldr r3, [r1]
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ldr r2, [r0, r3, lsl #3]
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cmn r2, #1
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ittt ne
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ldrne r3, [r1, #4]
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addne r3, r2, r3
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rsbne r0, r4, r3
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bne 2f
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1: mov r0, r1
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bl __tls_get_addr
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rsb r0, r4, r0
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2: pop {r2,r3,r4, lr}
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cfi_adjust_cfa_offset (-16)
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cfi_restore (lr)
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cfi_restore (r4)
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cfi_restore (r3)
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cfi_restore (r2)
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BX (lr)
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.fnend
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cfi_endproc
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.size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
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#endif /* SHARED */
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/* lazy resolved for tls descriptors. */
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.hidden _dl_tlsdesc_lazy_resolver
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.global _dl_tlsdesc_lazy_resolver
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.type _dl_tlsdesc_lazy_resolver,#function
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cfi_startproc
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.fnstart
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.align 2
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_dl_tlsdesc_lazy_resolver:
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/* r0 points at the tlsdesc,
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r1 points at the GOT
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r2 was pushed by the trampoline and used as a temp,
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we need to pop it here.
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We push the remaining call-clobbered registers here, and also
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R1 -- to keep the stack correctly aligned. */
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/* Tell the unwinder that r2 has already been pushed. */
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.save {r2}
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cfi_adjust_cfa_offset (4)
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cfi_rel_offset (r2, 0)
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.save {r0,r1,r3,ip,lr}
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push {r0, r1, r3, ip, lr}
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cfi_adjust_cfa_offset (20)
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cfi_rel_offset (r0, 0)
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cfi_rel_offset (r1, 4)
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cfi_rel_offset (r3, 8)
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cfi_rel_offset (ip, 12)
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cfi_rel_offset (lr, 16)
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bl _dl_tlsdesc_lazy_resolver_fixup
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pop {r0, r1, r3, ip, lr}
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cfi_adjust_cfa_offset (-20)
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cfi_restore (lr)
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cfi_restore (ip)
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cfi_restore (r3)
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cfi_restore (r1)
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cfi_restore (r0)
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pop {r2}
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cfi_adjust_cfa_offset (-4)
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cfi_restore (r2)
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ldr r1, [r0, #4]
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BX (r1)
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.fnend
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cfi_endproc
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.size _dl_tlsdesc_lazy_resolver, .-_dl_tlsdesc_lazy_resolver
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/* Holder for lazy tls descriptors being resolve in another thread.
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Same ABI as the lazy resolver itself. */
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.hidden _dl_tlsdesc_resolve_hold
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.global _dl_tlsdesc_resolve_hold
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.type _dl_tlsdesc_resolve_hold,#function
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cfi_startproc
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.fnstart
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.align 2
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_dl_tlsdesc_resolve_hold:
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/* Tell the unwinder that r2 has already been pushed. */
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.save {r2}
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cfi_adjust_cfa_offset (4)
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cfi_rel_offset (r2, 0)
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.save {r0,r1,r3,ip,lr}
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push {r0, r1, r3, ip, lr}
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cfi_adjust_cfa_offset (20)
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cfi_rel_offset (r0, 0)
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cfi_rel_offset (r1, 4)
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cfi_rel_offset (r3, 8)
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cfi_rel_offset (ip, 12)
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cfi_rel_offset (lr, 16)
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adr r2, _dl_tlsdesc_resolve_hold
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bl _dl_tlsdesc_resolve_hold_fixup
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pop {r0, r1, r3, ip, lr}
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cfi_adjust_cfa_offset (-20)
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cfi_restore (lr)
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cfi_restore (ip)
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cfi_restore (r3)
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cfi_restore (r1)
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cfi_restore (r0)
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pop {r2}
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cfi_adjust_cfa_offset (-4)
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cfi_restore (r2)
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ldr r1, [r0, #4]
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BX (r1)
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.fnend
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cfi_endproc
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.size _dl_tlsdesc_resolve_hold, .-_dl_tlsdesc_resolve_hold
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