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233 lines
6.6 KiB
C
233 lines
6.6 KiB
C
/* Target-dependent code for GNU/Linux x86-64.
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Copyright 2001, 2003, 2004 Free Software Foundation, Inc.
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Contributed by Jiri Smid, SuSE Labs.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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#include "frame.h"
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#include "gdbcore.h"
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#include "regcache.h"
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#include "osabi.h"
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#include "symtab.h"
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#include "gdb_string.h"
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#include "amd64-tdep.h"
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#include "solib-svr4.h"
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/* Mapping between the general-purpose registers in `struct user'
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format and GDB's register cache layout. */
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/* From <sys/reg.h>. */
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static int amd64_linux_gregset_reg_offset[] =
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{
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10 * 8, /* %rax */
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5 * 8, /* %rbx */
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11 * 8, /* %rcx */
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12 * 8, /* %rdx */
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13 * 8, /* %rsi */
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14 * 8, /* %rdi */
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4 * 8, /* %rbp */
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19 * 8, /* %rsp */
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9 * 8, /* %r8 ... */
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8 * 8,
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7 * 8,
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6 * 8,
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3 * 8,
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2 * 8,
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1 * 8,
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0 * 8, /* ... %r15 */
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16 * 8, /* %rip */
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18 * 8, /* %eflags */
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17 * 8, /* %cs */
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20 * 8, /* %ss */
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23 * 8, /* %ds */
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24 * 8, /* %es */
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25 * 8, /* %fs */
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26 * 8 /* %gs */
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};
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/* Support for signal handlers. */
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#define LINUX_SIGTRAMP_INSN0 0x48 /* mov $NNNNNNNN, %rax */
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#define LINUX_SIGTRAMP_OFFSET0 0
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#define LINUX_SIGTRAMP_INSN1 0x0f /* syscall */
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#define LINUX_SIGTRAMP_OFFSET1 7
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static const unsigned char linux_sigtramp_code[] =
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{
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/* mov $__NR_rt_sigreturn, %rax */
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LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x0f, 0x00, 0x00, 0x00,
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/* syscall */
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LINUX_SIGTRAMP_INSN1, 0x05
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};
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#define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code)
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/* If PC is in a sigtramp routine, return the address of the start of
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the routine. Otherwise, return 0. */
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static CORE_ADDR
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amd64_linux_sigtramp_start (CORE_ADDR pc)
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{
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unsigned char buf[LINUX_SIGTRAMP_LEN];
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/* We only recognize a signal trampoline if PC is at the start of
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one of the two instructions. We optimize for finding the PC at
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the start, as will be the case when the trampoline is not the
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first frame on the stack. We assume that in the case where the
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PC is not at the start of the instruction sequence, there will be
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a few trailing readable bytes on the stack. */
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if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0)
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return 0;
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if (buf[0] != LINUX_SIGTRAMP_INSN0)
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{
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if (buf[0] != LINUX_SIGTRAMP_INSN1)
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return 0;
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pc -= LINUX_SIGTRAMP_OFFSET1;
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if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0)
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return 0;
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}
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if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0)
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return 0;
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return pc;
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}
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/* Return whether the frame preceding NEXT_FRAME corresponds to a
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GNU/Linux sigtramp routine. */
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static int
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amd64_linux_sigtramp_p (struct frame_info *next_frame)
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{
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CORE_ADDR pc = frame_pc_unwind (next_frame);
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char *name;
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find_pc_partial_function (pc, &name, NULL, NULL);
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/* If we have NAME, we can optimize the search. The trampoline is
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named __restore_rt. However, it isn't dynamically exported from
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the shared C library, so the trampoline may appear to be part of
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the preceding function. This should always be sigaction,
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__sigaction, or __libc_sigaction (all aliases to the same
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function). */
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if (name == NULL || strstr (name, "sigaction") != NULL)
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return (amd64_linux_sigtramp_start (pc) != 0);
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return (strcmp ("__restore_rt", name) == 0);
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}
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/* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */
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#define AMD64_LINUX_UCONTEXT_SIGCONTEXT_OFFSET 40
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/* Assuming NEXT_FRAME is a frame following a GNU/Linux sigtramp
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routine, return the address of the associated sigcontext structure. */
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static CORE_ADDR
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amd64_linux_sigcontext_addr (struct frame_info *next_frame)
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{
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CORE_ADDR sp;
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char buf[8];
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frame_unwind_register (next_frame, SP_REGNUM, buf);
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sp = extract_unsigned_integer (buf, 8);
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/* The sigcontext structure is part of the user context. A pointer
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to the user context is passed as the third argument to the signal
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handler, i.e. in %rdx. Unfortunately %rdx isn't preserved across
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function calls so we can't use it. Fortunately the user context
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is part of the signal frame and the unwound %rsp directly points
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at it. */
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return sp + AMD64_LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
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}
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/* From <asm/sigcontext.h>. */
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static int amd64_linux_sc_reg_offset[] =
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{
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13 * 8, /* %rax */
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11 * 8, /* %rbx */
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14 * 8, /* %rcx */
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12 * 8, /* %rdx */
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9 * 8, /* %rsi */
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8 * 8, /* %rdi */
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10 * 8, /* %rbp */
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15 * 8, /* %rsp */
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0 * 8, /* %r8 */
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1 * 8, /* %r9 */
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2 * 8, /* %r10 */
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3 * 8, /* %r11 */
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4 * 8, /* %r12 */
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5 * 8, /* %r13 */
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6 * 8, /* %r14 */
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7 * 8, /* %r15 */
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16 * 8, /* %rip */
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17 * 8, /* %eflags */
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/* FIXME: kettenis/2002030531: The registers %cs, %fs and %gs are
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available in `struct sigcontext'. However, they only occupy two
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bytes instead of four, which makes using them here rather
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difficult. Leave them out for now. */
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-1, /* %cs */
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-1, /* %ss */
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-1, /* %ds */
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-1, /* %es */
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-1, /* %fs */
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-1 /* %gs */
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};
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static void
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amd64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
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tdep->gregset_reg_offset = amd64_linux_gregset_reg_offset;
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tdep->gregset_num_regs = ARRAY_SIZE (amd64_linux_gregset_reg_offset);
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tdep->sizeof_gregset = 27 * 8;
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amd64_init_abi (info, gdbarch);
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tdep->sigtramp_p = amd64_linux_sigtramp_p;
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tdep->sigcontext_addr = amd64_linux_sigcontext_addr;
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tdep->sc_reg_offset = amd64_linux_sc_reg_offset;
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tdep->sc_num_regs = ARRAY_SIZE (amd64_linux_sc_reg_offset);
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/* GNU/Linux uses SVR4-style shared libraries. */
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set_solib_svr4_fetch_link_map_offsets
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(gdbarch, svr4_lp64_fetch_link_map_offsets);
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}
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/* Provide a prototype to silence -Wmissing-prototypes. */
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extern void _initialize_amd64_linux_tdep (void);
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void
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_initialize_amd64_linux_tdep (void)
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{
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gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
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GDB_OSABI_LINUX, amd64_linux_init_abi);
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}
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