162 lines
4.9 KiB
C
162 lines
4.9 KiB
C
/* crtbegin object for windows32 targets.
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Copyright (C) 2007-2020 Free Software Foundation, Inc.
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Contributed by Danny Smith <dannysmith@users.sourceforge.net>
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* Target machine header files require this define. */
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#define IN_LIBGCC2
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#include "auto-host.h"
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#include "tconfig.h"
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#include "tsystem.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "libgcc_tm.h"
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#include "unwind-dw2-fde.h"
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#define WIN32_LEAN_AND_MEAN
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#include <windows.h>
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#ifndef LIBGCC_SONAME
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#define LIBGCC_SONAME "libgcc_s.dll"
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#endif
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#if DWARF2_UNWIND_INFO
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/* Make the declarations weak. This is critical for
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_Jv_RegisterClasses because it lives in libgcj.a */
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extern void __register_frame_info (__attribute__((unused)) const void *,
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__attribute__((unused)) struct object *)
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TARGET_ATTRIBUTE_WEAK;
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extern void *__deregister_frame_info (__attribute__((unused)) const void *)
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TARGET_ATTRIBUTE_WEAK;
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/* Work around for current cygwin32 build problems (Bug gas/16858).
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Compile weak default functions only for 64-bit systems,
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when absolutely necessary. */
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#ifdef __x86_64__
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TARGET_ATTRIBUTE_WEAK void
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__register_frame_info (__attribute__((unused)) const void *p,
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__attribute__((unused)) struct object *o)
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{
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}
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TARGET_ATTRIBUTE_WEAK void *
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__deregister_frame_info (__attribute__((unused)) const void *p)
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{
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return (void*) 0;
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}
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#endif
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#endif /* DWARF2_UNWIND_INFO */
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#if defined(HAVE_LD_RO_RW_SECTION_MIXING)
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# define EH_FRAME_SECTION_CONST const
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#else
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# define EH_FRAME_SECTION_CONST
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#endif
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/* Stick a label at the beginning of the frame unwind info so we can
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register/deregister it with the exception handling library code. */
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#if DWARF2_UNWIND_INFO
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static EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[]
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__attribute__((used, section(__LIBGCC_EH_FRAME_SECTION_NAME__), aligned(4)))
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= { };
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static struct object obj;
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/* Handle of libgcc's DLL reference. */
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HANDLE hmod_libgcc;
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static void * (*deregister_frame_fn) (const void *) = NULL;
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#endif
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#ifdef __CYGWIN__
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/* Declare the __dso_handle variable. It should have a unique value
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in every shared-object; in a main program its value is zero. The
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object should in any case be protected. This means the instance
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in one DSO or the main program is not used in another object. The
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dynamic linker takes care of this. */
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#ifdef CRTSTUFFS_O
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extern void *__ImageBase;
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void *__dso_handle = &__ImageBase;
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#else
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void *__dso_handle = 0;
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#endif
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#endif /* __CYGWIN__ */
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/* Pull in references from libgcc.a(unwind-dw2-fde.o) in the
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startfile. These are referenced by a ctor and dtor in crtend.o. */
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extern void __gcc_register_frame (void);
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extern void __gcc_deregister_frame (void);
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void
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__gcc_register_frame (void)
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{
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#if DWARF2_UNWIND_INFO
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/* Weak undefined symbols won't be pulled in from dlls; hence
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we first test if the dll is already loaded and, if so,
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get the symbol's address at run-time. If the dll is not loaded,
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fallback to weak linkage to static archive. */
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void (*register_frame_fn) (const void *, struct object *);
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HANDLE h = GetModuleHandle (LIBGCC_SONAME);
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if (h)
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{
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/* Increasing the load-count of LIBGCC_SONAME DLL. */
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hmod_libgcc = LoadLibrary (LIBGCC_SONAME);
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register_frame_fn = (void (*) (const void *, struct object *))
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GetProcAddress (h, "__register_frame_info");
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deregister_frame_fn = (void* (*) (const void *))
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GetProcAddress (h, "__deregister_frame_info");
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}
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else
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{
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register_frame_fn = __register_frame_info;
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deregister_frame_fn = __deregister_frame_info;
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}
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if (register_frame_fn)
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register_frame_fn (__EH_FRAME_BEGIN__, &obj);
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#endif
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#if DEFAULT_USE_CXA_ATEXIT
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/* If we use the __cxa_atexit method to register C++ dtors
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at object construction, also use atexit to register eh frame
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info cleanup. */
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atexit(__gcc_deregister_frame);
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#endif /* DEFAULT_USE_CXA_ATEXIT */
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}
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void
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__gcc_deregister_frame (void)
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{
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#if DWARF2_UNWIND_INFO
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if (deregister_frame_fn)
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deregister_frame_fn (__EH_FRAME_BEGIN__);
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if (hmod_libgcc)
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FreeLibrary (hmod_libgcc);
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#endif
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}
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