libpthread/nptl/sysdeps/unix/sysv/linux/xtensa/pt-initfini.c

   1 /* Special .init and .fini section support.  Linuxthread version.
   2    Copyright (C) 1995,1996,1997,2000,2001,2002 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it
   6    and/or modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2 of the License, or (at your option) any later version.
   9
  10    In addition to the permissions in the GNU Lesser General Public
  11    License, the Free Software Foundation gives you unlimited
  12    permission to link the compiled version of this file with other
  13    programs, and to distribute those programs without any restriction
  14    coming from the use of this file.  (The Library General Public
  15    License restrictions do apply in other respects; for example, they
  16    cover modification of the file, and distribution when not linked
  17    into another program.)
  18
  19    The GNU C Library is distributed in the hope that it will be
  20    useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  21    of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22    GNU Lesser General Public License for more details.
  23
  24    You should have received a copy of the GNU Lesser General Public
  25    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  26    see <http://www.gnu.org/licenses/>.  */
  27
  28 /* This file is compiled into assembly code which is then munged by a sed
  29    script into two files: crti.s and crtn.s.
  30
  31    * crti.s puts a function prologue at the beginning of the
  32    .init and .fini sections and defines global symbols for
  33    those addresses, so they can be called as functions.
  34
  35    * crtn.s puts the corresponding function epilogues
  36    in the .init and .fini sections. */
  37
  38 #include <stdlib.h>
  39
  40 /* We use embedded asm for .section unconditionally, as this makes it
  41    easier to insert the necessary directives into crtn.S. */
  42 #define SECTION(x) __asm__ (".section " x )
  43
  44 /* Embed an #include to pull in the alignment and .end directives. */
  45 __asm__ ("\n#include \"defs.h\"");
  46 __asm__ ("\n#if defined __i686 && defined __ASSEMBLER__");
  47 __asm__ ("\n#undef __i686");
  48 __asm__ ("\n#define __i686 __i686");
  49 __asm__ ("\n#endif");
  50
  51 /* The initial common code ends here. */
  52 __asm__ ("\n/*@HEADER_ENDS*/");
  53
  54 /* To determine whether we need .end and .align: */
  55 __asm__ ("\n/*@TESTS_BEGIN*/");
  56 extern void dummy (void (*foo) (void));
  57 void
  58 dummy (void (*foo) (void))
  59 {
  60   if (foo)
  61     (*foo) ();
  62 }
  63 __asm__ ("\n/*@TESTS_END*/");
  64
  65 /* The beginning of _init:  */
  66 __asm__ ("\n/*@_init_PROLOG_BEGINS*/");
  67
  68 static void
  69 call_initialize_minimal (void)
  70 {
  71   extern void __pthread_initialize_minimal_internal (void)
  72     __attribute ((visibility ("hidden")));
  73
  74   __pthread_initialize_minimal_internal ();
  75 }
  76
  77 SECTION (".init");
  78 extern void __attribute__ ((section (".init"))) _init (void);
  79 void
  80 _init (void)
  81 {
  82   /* The very first thing we must do is to set up the registers.  */
  83   call_initialize_minimal ();
  84
  85   __asm__ ("ALIGN");
  86   __asm__("END_INIT");
  87   /* Now the epilog. */
  88   __asm__ ("\n/*@_init_PROLOG_ENDS*/");
  89   __asm__ ("\n/*@_init_EPILOG_BEGINS*/");
  90   SECTION(".init");
  91 }
  92 __asm__ ("END_INIT");
  93
  94 /* End of the _init epilog, beginning of the _fini prolog. */
  95 __asm__ ("\n/*@_init_EPILOG_ENDS*/");
  96 __asm__ ("\n/*@_fini_PROLOG_BEGINS*/");
  97
  98 SECTION (".fini");
  99 extern void __attribute__ ((section (".fini"))) _fini (void);
 100 void
 101 _fini (void)
 102 {
 103
 104   /* End of the _fini prolog. */
 105   __asm__ ("ALIGN");
 106   __asm__ ("END_FINI");
 107   __asm__ ("\n/*@_fini_PROLOG_ENDS*/");
 108
 109   /* Xtensa: It doesn't really matter whether GCC thinks this is a leaf
 110      function or not, and the scripts that are supposed to remove the
 111      call don't catch the literal, resulting in an undefined symbol
 112      reference.  */
 113 #if 0
 114   {
 115     /* Let GCC know that _fini is not a leaf function by having a dummy
 116        function call here.  We arrange for this call to be omitted from
 117        either crt file.  */
 118     extern void i_am_not_a_leaf (void);
 119     i_am_not_a_leaf ();
 120   }
 121 #endif
 122
 123   /* Beginning of the _fini epilog. */
 124   __asm__ ("\n/*@_fini_EPILOG_BEGINS*/");
 125   SECTION (".fini");
 126 }
 127 __asm__ ("END_FINI");
 128
 129 /* End of the _fini epilog.  Any further generated assembly (e.g. .ident)
 130    is shared between both crt files. */
 131 __asm__ ("\n/*@_fini_EPILOG_ENDS*/");
 132 __asm__ ("\n/*@TRAILER_BEGINS*/");
 133
 134 /* End of file. */