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490e6c62aa
dynamic-link.h is included more than once in some elf/ files (rtld.c,
dl-conflict.c, dl-reloc.c, dl-reloc-static-pie.c) and uses GCC nested
functions. This harms readability and the nested functions usage
is the biggest obstacle prevents Clang build (Clang doesn't support GCC
nested functions).
The key idea for unnesting is to add extra parameters (struct link_map
*and struct r_scope_elm *[]) to RESOLVE_MAP,
ELF_MACHINE_BEFORE_RTLD_RELOC, ELF_DYNAMIC_RELOCATE, elf_machine_rel[a],
elf_machine_lazy_rel, and elf_machine_runtime_setup. (This is inspired
by Stan Shebs' ppc64/x86-64 implementation in the
google/grte/v5-2.27/master which uses mixed extra parameters and static
variables.)
Future simplification:
* If mips elf_machine_runtime_setup no longer needs RESOLVE_GOTSYM,
elf_machine_runtime_setup can drop the `scope` parameter.
* If TLSDESC no longer need to be in elf_machine_lazy_rel,
elf_machine_lazy_rel can drop the `scope` parameter.
Tested on aarch64, i386, x86-64, powerpc64le, powerpc64, powerpc32,
sparc64, sparcv9, s390x, s390, hppa, ia64, armhf, alpha, and mips64.
In addition, tested build-many-glibcs.py with {arc,csky,microblaze,nios2}-linux-gnu
and riscv64-linux-gnu-rv64imafdc-lp64d.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
206 lines
8.3 KiB
C
206 lines
8.3 KiB
C
/* Inline functions for dynamic linking.
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Copyright (C) 1995-2021 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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<https://www.gnu.org/licenses/>. */
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/* This macro is used as a callback from elf_machine_rel{a,} when a
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static TLS reloc is about to be performed. Since (in dl-load.c) we
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permit dynamic loading of objects that might use such relocs, we
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have to check whether each use is actually doable. If the object
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whose TLS segment the reference resolves to was allocated space in
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the static TLS block at startup, then it's ok. Otherwise, we make
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an attempt to allocate it in surplus space on the fly. If that
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can't be done, we fall back to the error that DF_STATIC_TLS is
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intended to produce. */
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#define HAVE_STATIC_TLS(map, sym_map) \
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(__builtin_expect ((sym_map)->l_tls_offset != NO_TLS_OFFSET \
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&& ((sym_map)->l_tls_offset \
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!= FORCED_DYNAMIC_TLS_OFFSET), 1))
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#define CHECK_STATIC_TLS(map, sym_map) \
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do { \
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if (!HAVE_STATIC_TLS (map, sym_map)) \
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_dl_allocate_static_tls (sym_map); \
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} while (0)
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#define TRY_STATIC_TLS(map, sym_map) \
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(__builtin_expect ((sym_map)->l_tls_offset \
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!= FORCED_DYNAMIC_TLS_OFFSET, 1) \
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&& (__builtin_expect ((sym_map)->l_tls_offset != NO_TLS_OFFSET, 1) \
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|| _dl_try_allocate_static_tls (sym_map, true) == 0))
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int _dl_try_allocate_static_tls (struct link_map *map, bool optional)
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attribute_hidden;
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#include <elf.h>
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#ifdef RESOLVE_MAP
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/* We pass reloc_addr as a pointer to void, as opposed to a pointer to
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ElfW(Addr), because not all architectures can assume that the
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relocated address is properly aligned, whereas the compiler is
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entitled to assume that a pointer to a type is properly aligned for
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the type. Even if we cast the pointer back to some other type with
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less strict alignment requirements, the compiler might still
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remember that the pointer was originally more aligned, thereby
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optimizing away alignment tests or using word instructions for
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copying memory, breaking the very code written to handle the
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unaligned cases. */
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# if ! ELF_MACHINE_NO_REL
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static inline void __attribute__((always_inline))
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elf_machine_rel (struct link_map *map, struct r_scope_elem *scope[],
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const ElfW(Rel) *reloc, const ElfW(Sym) *sym,
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const struct r_found_version *version,
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void *const reloc_addr, int skip_ifunc);
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static inline void __attribute__((always_inline))
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elf_machine_rel_relative (ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
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void *const reloc_addr);
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# endif
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# if ! ELF_MACHINE_NO_RELA
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static inline void __attribute__((always_inline))
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elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
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const ElfW(Rela) *reloc, const ElfW(Sym) *sym,
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const struct r_found_version *version, void *const reloc_addr,
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int skip_ifunc);
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static inline void __attribute__((always_inline))
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elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
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void *const reloc_addr);
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# endif
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# if ELF_MACHINE_NO_RELA || defined ELF_MACHINE_PLT_REL
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static inline void __attribute__((always_inline))
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elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
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ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
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int skip_ifunc);
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# else
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static inline void __attribute__((always_inline))
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elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
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ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
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int skip_ifunc);
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# endif
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#endif
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#include <dl-machine.h>
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#include "get-dynamic-info.h"
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#ifdef RESOLVE_MAP
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# if defined RTLD_BOOTSTRAP || defined STATIC_PIE_BOOTSTRAP
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# define ELF_DURING_STARTUP (1)
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# else
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# define ELF_DURING_STARTUP (0)
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# endif
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/* Get the definitions of `elf_dynamic_do_rel' and `elf_dynamic_do_rela'.
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These functions are almost identical, so we use cpp magic to avoid
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duplicating their code. It cannot be done in a more general function
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because we must be able to completely inline. */
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/* On some machines, notably SPARC, DT_REL* includes DT_JMPREL in its
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range. Note that according to the ELF spec, this is completely legal!
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We are guarenteed that we have one of three situations. Either DT_JMPREL
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comes immediately after DT_REL*, or there is overlap and DT_JMPREL
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consumes precisely the very end of the DT_REL*, or DT_JMPREL and DT_REL*
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are completely separate and there is a gap between them. */
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# define _ELF_DYNAMIC_DO_RELOC(RELOC, reloc, map, scope, do_lazy, skip_ifunc, test_rel) \
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do { \
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struct { ElfW(Addr) start, size; \
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__typeof (((ElfW(Dyn) *) 0)->d_un.d_val) nrelative; int lazy; } \
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ranges[2] = { { 0, 0, 0, 0 }, { 0, 0, 0, 0 } }; \
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\
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if ((map)->l_info[DT_##RELOC]) \
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{ \
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ranges[0].start = D_PTR ((map), l_info[DT_##RELOC]); \
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ranges[0].size = (map)->l_info[DT_##RELOC##SZ]->d_un.d_val; \
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if (map->l_info[VERSYMIDX (DT_##RELOC##COUNT)] != NULL) \
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ranges[0].nrelative \
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= map->l_info[VERSYMIDX (DT_##RELOC##COUNT)]->d_un.d_val; \
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} \
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if ((map)->l_info[DT_PLTREL] \
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&& (!test_rel || (map)->l_info[DT_PLTREL]->d_un.d_val == DT_##RELOC)) \
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{ \
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ElfW(Addr) start = D_PTR ((map), l_info[DT_JMPREL]); \
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ElfW(Addr) size = (map)->l_info[DT_PLTRELSZ]->d_un.d_val; \
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\
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if (ranges[0].start + ranges[0].size == (start + size)) \
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ranges[0].size -= size; \
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if (ELF_DURING_STARTUP \
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|| (!(do_lazy) \
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&& (ranges[0].start + ranges[0].size) == start)) \
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{ \
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/* Combine processing the sections. */ \
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ranges[0].size += size; \
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} \
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else \
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{ \
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ranges[1].start = start; \
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ranges[1].size = size; \
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ranges[1].lazy = (do_lazy); \
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} \
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} \
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\
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if (ELF_DURING_STARTUP) \
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elf_dynamic_do_##reloc ((map), scope, ranges[0].start, ranges[0].size, \
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ranges[0].nrelative, 0, skip_ifunc); \
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else \
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{ \
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int ranges_index; \
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for (ranges_index = 0; ranges_index < 2; ++ranges_index) \
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elf_dynamic_do_##reloc ((map), scope, \
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ranges[ranges_index].start, \
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ranges[ranges_index].size, \
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ranges[ranges_index].nrelative, \
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ranges[ranges_index].lazy, \
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skip_ifunc); \
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} \
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} while (0)
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# if ELF_MACHINE_NO_REL || ELF_MACHINE_NO_RELA
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# define _ELF_CHECK_REL 0
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# else
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# define _ELF_CHECK_REL 1
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# endif
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# if ! ELF_MACHINE_NO_REL
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# include "do-rel.h"
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# define ELF_DYNAMIC_DO_REL(map, scope, lazy, skip_ifunc) \
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_ELF_DYNAMIC_DO_RELOC (REL, Rel, map, scope, lazy, skip_ifunc, _ELF_CHECK_REL)
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# else
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# define ELF_DYNAMIC_DO_REL(map, scope, lazy, skip_ifunc) /* Nothing to do. */
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# endif
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# if ! ELF_MACHINE_NO_RELA
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# define DO_RELA
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# include "do-rel.h"
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# define ELF_DYNAMIC_DO_RELA(map, scope, lazy, skip_ifunc) \
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_ELF_DYNAMIC_DO_RELOC (RELA, Rela, map, scope, lazy, skip_ifunc, _ELF_CHECK_REL)
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# else
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# define ELF_DYNAMIC_DO_RELA(map, scope, lazy, skip_ifunc) /* Nothing to do. */
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# endif
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/* This can't just be an inline function because GCC is too dumb
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to inline functions containing inlines themselves. */
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# define ELF_DYNAMIC_RELOCATE(map, scope, lazy, consider_profile, skip_ifunc) \
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do { \
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int edr_lazy = elf_machine_runtime_setup ((map), (scope), (lazy), \
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(consider_profile)); \
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ELF_DYNAMIC_DO_REL ((map), (scope), edr_lazy, skip_ifunc); \
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ELF_DYNAMIC_DO_RELA ((map), (scope), edr_lazy, skip_ifunc); \
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} while (0)
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#endif
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