19ba224fb8
When `ptrauth_calls` is present but `ptrauth_init_fini` is not, compiler emits raw unsigned pointers in `.init_array`/`.fini_array` sections. Previously, `__do_init`/`__do_fini` pointers, which are explicitly added to the sections, were implicitly signed (due to the presense of `ptrauth_calls`), while all the other pointers in the sections were implicitly added by the compiler and thus non-signed.. As a result, the sections contained a mix of unsigned function pointers and function pointers signed with default signing schema. This patch introduces use of inline assembly for this particular case, so we can manually specify that we do not want to sign the pointers. Note that we cannot use `__builtin_ptrauth_strip` for this purpose since its result is not a constant expression.
194 lines
6.6 KiB
C
194 lines
6.6 KiB
C
//===-- crtbegin.c - Start of constructors and destructors ----------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include <stddef.h>
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#ifndef __has_feature
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# define __has_feature(x) 0
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#endif
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#if __has_feature(ptrauth_init_fini)
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#include <ptrauth.h>
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#endif
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__attribute__((visibility("hidden"))) void *__dso_handle = &__dso_handle;
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#ifdef EH_USE_FRAME_REGISTRY
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__extension__ static void *__EH_FRAME_LIST__[]
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__attribute__((section(".eh_frame"), aligned(sizeof(void *)))) = {};
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extern void __register_frame_info(const void *, void *) __attribute__((weak));
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extern void *__deregister_frame_info(const void *) __attribute__((weak));
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#endif
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#ifndef CRT_HAS_INITFINI_ARRAY
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typedef void (*fp)(void);
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static fp __CTOR_LIST__[]
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__attribute__((section(".ctors"), aligned(sizeof(fp)))) = {(fp)-1};
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extern fp __CTOR_LIST_END__[];
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#endif
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extern void __cxa_finalize(void *) __attribute__((weak));
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static void __attribute__((used)) __do_init(void) {
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static _Bool __initialized;
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if (__builtin_expect(__initialized, 0))
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return;
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__initialized = 1;
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#ifdef EH_USE_FRAME_REGISTRY
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static struct { void *p[8]; } __object;
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if (__register_frame_info)
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__register_frame_info(__EH_FRAME_LIST__, &__object);
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#endif
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#ifndef CRT_HAS_INITFINI_ARRAY
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const size_t n = __CTOR_LIST_END__ - __CTOR_LIST__ - 1;
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for (size_t i = n; i >= 1; i--) __CTOR_LIST__[i]();
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#endif
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}
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#ifdef CRT_HAS_INITFINI_ARRAY
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# if __has_feature(ptrauth_init_fini)
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// TODO: use __ptrauth-qualified pointers when they are supported on clang side
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# if __has_feature(ptrauth_init_fini_address_discrimination)
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__attribute__((section(".init_array"), used)) static void *__init =
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ptrauth_sign_constant(&__do_init, ptrauth_key_init_fini_pointer,
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ptrauth_blend_discriminator(
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&__init, __ptrauth_init_fini_discriminator));
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# else
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__attribute__((section(".init_array"), used)) static void *__init =
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ptrauth_sign_constant(&__do_init, ptrauth_key_init_fini_pointer,
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__ptrauth_init_fini_discriminator);
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# endif
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# elif __has_feature(ptrauth_calls)
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# ifdef __aarch64__
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// If ptrauth_init_fini feature is not present, compiler emits raw unsigned
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// pointers in .init_array. Use inline assembly to avoid implicit signing of
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// __do_init function pointer with ptrauth_calls enabled.
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__asm__(".pushsection .init_array,\"aw\",@init_array\n\t"
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".xword __do_init\n\t"
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".popsection");
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# else
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# error "ptrauth_calls is only supported for AArch64"
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# endif
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# else
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__attribute__((section(".init_array"),
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used)) static void (*__init)(void) = __do_init;
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# endif
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#elif defined(__i386__) || defined(__x86_64__)
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__asm__(".pushsection .init,\"ax\",@progbits\n\t"
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"call __do_init\n\t"
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".popsection");
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#elif defined(__riscv)
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__asm__(".pushsection .init,\"ax\",%progbits\n\t"
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"call __do_init\n\t"
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".popsection");
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#elif defined(__arm__) || defined(__aarch64__)
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__asm__(".pushsection .init,\"ax\",%progbits\n\t"
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"bl __do_init\n\t"
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".popsection");
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#elif defined(__mips__)
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__asm__(".pushsection .init,\"ax\",@progbits\n\t"
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"jal __do_init\n\t"
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".popsection");
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#elif defined(__powerpc__) || defined(__powerpc64__)
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__asm__(".pushsection .init,\"ax\",@progbits\n\t"
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"bl __do_init\n\t"
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"nop\n\t"
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".popsection");
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#elif defined(__sparc__)
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__asm__(".pushsection .init,\"ax\",@progbits\n\t"
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"call __do_init\n\t"
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".popsection");
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#else
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#error "crtbegin without .init_fini array unimplemented for this architecture"
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#endif // CRT_HAS_INITFINI_ARRAY
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#ifndef CRT_HAS_INITFINI_ARRAY
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static fp __DTOR_LIST__[]
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__attribute__((section(".dtors"), aligned(sizeof(fp)))) = {(fp)-1};
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extern fp __DTOR_LIST_END__[];
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#endif
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static void __attribute__((used)) __do_fini(void) {
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static _Bool __finalized;
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if (__builtin_expect(__finalized, 0))
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return;
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__finalized = 1;
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if (__cxa_finalize)
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__cxa_finalize(__dso_handle);
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#ifndef CRT_HAS_INITFINI_ARRAY
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const size_t n = __DTOR_LIST_END__ - __DTOR_LIST__ - 1;
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for (size_t i = 1; i <= n; i++) __DTOR_LIST__[i]();
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#endif
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#ifdef EH_USE_FRAME_REGISTRY
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if (__deregister_frame_info)
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__deregister_frame_info(__EH_FRAME_LIST__);
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#endif
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}
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#ifdef CRT_HAS_INITFINI_ARRAY
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# if __has_feature(ptrauth_init_fini)
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// TODO: use __ptrauth-qualified pointers when they are supported on clang side
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# if __has_feature(ptrauth_init_fini_address_discrimination)
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__attribute__((section(".fini_array"), used)) static void *__fini =
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ptrauth_sign_constant(&__do_fini, ptrauth_key_init_fini_pointer,
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ptrauth_blend_discriminator(
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&__fini, __ptrauth_init_fini_discriminator));
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# else
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__attribute__((section(".fini_array"), used)) static void *__fini =
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ptrauth_sign_constant(&__do_fini, ptrauth_key_init_fini_pointer,
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__ptrauth_init_fini_discriminator);
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# endif
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# elif __has_feature(ptrauth_calls)
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# ifdef __aarch64__
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// If ptrauth_init_fini feature is not present, compiler emits raw unsigned
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// pointers in .fini_array. Use inline assembly to avoid implicit signing of
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// __do_fini function pointer with ptrauth_calls enabled.
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__asm__(".pushsection .fini_array,\"aw\",@fini_array\n\t"
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".xword __do_fini\n\t"
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".popsection");
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# else
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# error "ptrauth_calls is only supported for AArch64"
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# endif
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# else
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__attribute__((section(".fini_array"),
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used)) static void (*__fini)(void) = __do_fini;
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# endif
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#elif defined(__i386__) || defined(__x86_64__)
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__asm__(".pushsection .fini,\"ax\",@progbits\n\t"
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"call __do_fini\n\t"
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".popsection");
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#elif defined(__arm__) || defined(__aarch64__)
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__asm__(".pushsection .fini,\"ax\",%progbits\n\t"
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"bl __do_fini\n\t"
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".popsection");
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#elif defined(__mips__)
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__asm__(".pushsection .fini,\"ax\",@progbits\n\t"
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"jal __do_fini\n\t"
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".popsection");
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#elif defined(__powerpc__) || defined(__powerpc64__)
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__asm__(".pushsection .fini,\"ax\",@progbits\n\t"
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"bl __do_fini\n\t"
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"nop\n\t"
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".popsection");
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#elif defined(__riscv)
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__asm__(".pushsection .fini,\"ax\",@progbits\n\t"
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"call __do_fini\n\t"
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".popsection");
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#elif defined(__sparc__)
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__asm__(".pushsection .fini,\"ax\",@progbits\n\t"
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"call __do_fini\n\t"
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".popsection");
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#else
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#error "crtbegin without .init_fini array unimplemented for this architecture"
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#endif // CRT_HAS_INIT_FINI_ARRAY
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