lib/csu/common_elf/crtbegin.c

   1 /*      $NetBSD: crtbegin.c,v 1.28 2006/05/19 19:11:12 christos Exp $   */
   2
   3 /*-
   4  * Copyright (c) 1998, 2001, 2002 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Paul Kranenburg, Ross Harvey, and Jason R. Thorpe.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * Run-time module which handles constructors and destructors,
  34  * and NetBSD identification.
  35  *
  36  * The linker constructs the following arrays of pointers to global
  37  * constructors and destructors. The first element contains the
  38  * number of pointers in each or -1 to indicate that the run-time
  39  * code should figure out how many there are.  The tables are also
  40  * null-terminated.
  41  */
  42
  43 #include <sys/param.h>
  44 #include <sys/exec.h>
  45 #include <sys/exec_elf.h>
  46 #include <stdlib.h>
  47
  48 /*
  49  * WE SHOULD BE USING GCC-SUPPLIED crtbegin.o FOR GCC 3.3 AND
  50  * LATER!!!
  51  */
  52 #if __GNUC_PREREQ__(3, 3)
  53 #error "Use GCC-supplied crtbegin.o"
  54 #endif
  55
  56 #if __GNUC_PREREQ__(3, 0)
  57 #define USED_NOINLINE __attribute__((__used__,__noinline__))
  58 #else
  59 #define USED_NOINLINE __attribute__((__unused__))
  60 #endif
  61
  62 #ifdef DWARF2_EH
  63 #include "dwarf2_eh.h"
  64 #endif
  65 #include <dot_init.h>
  66
  67 static void (*__CTOR_LIST__[1])(void)
  68     __attribute__((section(".ctors"))) = { (void *)-1 };        /* XXX */
  69 static void (*__DTOR_LIST__[1])(void)
  70     __attribute__((section(".dtors"))) = { (void *)-1 };        /* XXX */
  71
  72 #ifdef DWARF2_EH
  73 static __EH_FRAME_CONST char __EH_FRAME_BEGIN__[]
  74     __attribute__((section(".eh_frame"), aligned(4))) = { };
  75 #endif
  76
  77 #if defined(JCR) && defined(__GNUC__)
  78 extern void _Jv_RegisterClasses(void *) __attribute__((weak));
  79
  80 static void *__JCR_LIST__[]
  81     __attribute__((section(".jcr"))) = { };
  82 #endif
  83
  84 #if defined(DSO_HANDLE) && defined(__GNUC__)
  85 /*
  86  * The __dso_handle variable is used to hang C++ local destructors off
  87  * of.  In the main program (i.e. using crtbegin.o), the value is 0.
  88  * In shared objects (i.e. using crtbeginS.o), the value must be unique.
  89  * The symbol is hidden, but the dynamic linker will still relocate it.
  90  */
  91 #ifdef SHARED
  92 void    *__dso_handle = &__dso_handle;
  93 #else
  94 void    *__dso_handle = NULL;
  95 #endif
  96 __asm(".hidden  __dso_handle");
  97
  98 #ifdef SHARED
  99 extern void __cxa_finalize(void *) __attribute__((weak));
 100 #endif
 101 #endif
 102
 103 #ifndef MD_CALL_STATIC_FUNCTION
 104 #if defined(__GNUC__)
 105 #define MD_CALL_STATIC_FUNCTION(section, func)                          \
 106 static void __attribute__((__unused__))                                 \
 107 __call_##func(void)                                                     \
 108 {                                                                       \
 109         __asm volatile (".section " #section);                  \
 110         func();                                                         \
 111         __asm volatile (".previous");                                   \
 112 }
 113 #else
 114 #error Need MD_CALL_STATIC_FUNCTION
 115 #endif
 116 #endif /* ! MD_CALL_STATIC_FUNCTION */
 117
 118 static void
 119 __ctors(void)
 120 {
 121         unsigned long i = (unsigned long) __CTOR_LIST__[0];
 122         void (**p)(void);
 123
 124         if (i == (unsigned long) -1)  {
 125                 for (i = 1; __CTOR_LIST__[i] != NULL; i++)
 126                         ;
 127                 i--;
 128         }
 129         p = __CTOR_LIST__ + i;
 130         while (i--)
 131                 (**p--)();
 132 }
 133
 134 static void
 135 __dtors(void)
 136 {
 137         void (**p)(void) = __DTOR_LIST__ + 1;
 138
 139         while (*p)
 140                 (**p++)();
 141 }
 142
 143 static void USED_NOINLINE
 144 __do_global_ctors_aux(void)
 145 {
 146         static int initialized;
 147 #ifdef DWARF2_EH
 148 #if defined(__GNUC__)
 149         static struct dwarf2_eh_object object;
 150 #endif /* __GNUC__ */
 151 #endif /* DWARF2_EH */
 152
 153         if (!initialized) {
 154                 initialized = 1;
 155
 156 #ifdef DWARF2_EH
 157 #if defined(__GNUC__)
 158                 if (__register_frame_info != NULL)
 159                         __register_frame_info(__EH_FRAME_BEGIN__, &object);
 160 #endif /* __GNUC__ */
 161 #endif /* DWARF2_EH */
 162
 163 #if defined(JCR) && defined(__GNUC__)
 164                 if (__JCR_LIST__[0] != NULL && _Jv_RegisterClasses != NULL)
 165                         _Jv_RegisterClasses(__JCR_LIST__);
 166 #endif /* JCR && __GNUC__ */
 167
 168                 /*
 169                  * Call global constructors.
 170                  */
 171                 __ctors();
 172         }
 173 }
 174 MD_CALL_STATIC_FUNCTION(.init, __do_global_ctors_aux)
 175
 176 static void USED_NOINLINE
 177 __do_global_dtors_aux(void)
 178 {
 179         static int finished;
 180
 181         if (finished)
 182                 return;
 183
 184 #if defined(DSO_HANDLE) && defined(__GNUC__) && defined(SHARED)
 185         /*
 186          * Call local destructors.
 187          */
 188         if (__cxa_finalize != NULL)
 189                 __cxa_finalize(__dso_handle);
 190 #endif /* DSO_HANDLE && __GNUC__ && SHARED */
 191
 192         /*
 193          * Call global destructors.
 194          */
 195         __dtors();
 196
 197 #ifdef DWARF2_EH
 198 #if defined(__GNUC__)
 199         if (__deregister_frame_info != NULL)
 200                 __deregister_frame_info(__EH_FRAME_BEGIN__);
 201 #endif /* __GNUC__ */
 202 #endif /* DWARF2_EH */
 203
 204         finished = 1;
 205 }
 206 MD_CALL_STATIC_FUNCTION(.fini, __do_global_dtors_aux)