[thirdparty/gcc.git] / gcc / crtstuff.c

/* Specialized bits of code needed to support construction and
   destruction of file-scope objects in C++ code.
   Copyright (C) 1991, 1994, 1995, 1996 Free Software Foundation, Inc.
   Contributed by Ron Guilmette (rfg@monkeys.com).

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

/* As a special exception, if you link this library with files
   compiled with GCC to produce an executable, this does not cause
   the resulting executable to be covered by the GNU General Public License.
   This exception does not however invalidate any other reasons why
   the executable file might be covered by the GNU General Public License.  */

/* This file is a bit like libgcc1.c/libgcc2.c in that it is compiled
   multiple times and yields multiple .o files.

   This file is useful on target machines where the object file format
   supports multiple "user-defined" sections (e.g. COFF, ELF, ROSE).  On
   such systems, this file allows us to avoid running collect (or any
   other such slow and painful kludge).  Additionally, if the target
   system supports a .init section, this file allows us to support the
   linking of C++ code with a non-C++ main program.

   Note that if INIT_SECTION_ASM_OP is defined in the tm.h file, then
   this file *will* make use of the .init section.  If that symbol is
   not defined however, then the .init section will not be used.

   Currently, only ELF and COFF are supported.  It is likely however that
   ROSE could also be supported, if someone was willing to do the work to
   make whatever (small?) adaptations are needed.  (Some work may be
   needed on the ROSE assembler and linker also.)

   This file must be compiled with gcc.  */

/* It is incorrect to include config.h here, because this file is being
   compiled for the target, and hence definitions concerning only the host
   do not apply.  */

#include "tm.h"

/* Provide default definitions for the pseudo-ops used to switch to the
   .ctors and .dtors sections.
 
   Note that we want to give these sections the SHF_WRITE attribute
   because these sections will actually contain data (i.e. tables of
   addresses of functions in the current root executable or shared library
   file) and, in the case of a shared library, the relocatable addresses
   will have to be properly resolved/relocated (and then written into) by
   the dynamic linker when it actually attaches the given shared library
   to the executing process.  (Note that on SVR4, you may wish to use the
   `-z text' option to the ELF linker, when building a shared library, as
   an additional check that you are doing everything right.  But if you do
   use the `-z text' option when building a shared library, you will get
   errors unless the .ctors and .dtors sections are marked as writable
   via the SHF_WRITE attribute.)  */

#ifndef CTORS_SECTION_ASM_OP
#define CTORS_SECTION_ASM_OP	".section\t.ctors,\"aw\""
#endif
#ifndef DTORS_SECTION_ASM_OP
#define DTORS_SECTION_ASM_OP	".section\t.dtors,\"aw\""
#endif

#ifdef OBJECT_FORMAT_ELF

/*  Declare a pointer to void function type.  */
typedef void (*func_ptr) (void);
#define STATIC static

#else  /* OBJECT_FORMAT_ELF */

#include "gbl-ctors.h"

#ifndef ON_EXIT
#define ON_EXIT(a, b)
#endif
#define STATIC

#endif /* OBJECT_FORMAT_ELF */

#ifdef CRT_BEGIN

#ifdef INIT_SECTION_ASM_OP

#ifdef OBJECT_FORMAT_ELF

/* Run all the global destructors on exit from the program.  */
 
/* Some systems place the number of pointers in the first word of the
   table.  On SVR4 however, that word is -1.  In all cases, the table is
   null-terminated.  On SVR4, we start from the beginning of the list and
   invoke each per-compilation-unit destructor routine in order
   until we find that null.

   Note that this function MUST be static.  There will be one of these
   functions in each root executable and one in each shared library, but
   although they all have the same code, each one is unique in that it
   refers to one particular associated `__DTOR_LIST__' which belongs to the
   same particular root executable or shared library file.  */

static func_ptr __DTOR_LIST__[];
static void
__do_global_dtors_aux ()
{
  func_ptr *p;
  for (p = __DTOR_LIST__ + 1; *p; p++)
    (*p) ();
}

/* Stick a call to __do_global_dtors_aux into the .fini section.  */

static void
fini_dummy ()
{
  asm (FINI_SECTION_ASM_OP);
  __do_global_dtors_aux ();
#ifdef FORCE_FINI_SECTION_ALIGN
  FORCE_FINI_SECTION_ALIGN;
#endif
  asm (TEXT_SECTION_ASM_OP);
}

#else  /* OBJECT_FORMAT_ELF */

/* The function __do_global_ctors_aux is compiled twice (once in crtbegin.o
   and once in crtend.o).  It must be declared static to avoid a link
   error.  Here, we define __do_global_ctors as an externally callable
   function.  It is externally callable so that __main can invoke it when
   INVOKE__main is defined.  This has the additional effect of forcing cc1
   to switch to the .text section.  */

static void __do_global_ctors_aux ();
void __do_global_ctors ()
{
#ifdef INVOKE__main  /* If __main won't actually call __do_global_ctors
			then it doesn't matter what's inside the function.
			The inside of __do_global_ctors_aux is called
			automatically in that case.
			And the Alliant fx2800 linker crashes
			on this reference.  So prevent the crash.  */
  __do_global_ctors_aux ();
#endif
}

asm (INIT_SECTION_ASM_OP);	/* cc1 doesn't know that we are switching! */

/* On some svr4 systems, the initial .init section preamble code provided in
   crti.o may do something, such as bump the stack, which we have to 
   undo before we reach the function prologue code for __do_global_ctors 
   (directly below).  For such systems, define the macro INIT_SECTION_PREAMBLE
   to expand into the code needed to undo the actions of the crti.o file.  */

#ifdef INIT_SECTION_PREAMBLE
  INIT_SECTION_PREAMBLE;
#endif

/* A routine to invoke all of the global constructors upon entry to the
   program.  We put this into the .init section (for systems that have
   such a thing) so that we can properly perform the construction of
   file-scope static-storage C++ objects within shared libraries.   */

static void
__do_global_ctors_aux ()	/* prologue goes in .init section */
{
#ifdef FORCE_INIT_SECTION_ALIGN
  FORCE_INIT_SECTION_ALIGN;	/* Explicit align before switch to .text */
#endif
  asm (TEXT_SECTION_ASM_OP);	/* don't put epilogue and body in .init */
  DO_GLOBAL_CTORS_BODY;
  ON_EXIT (__do_global_dtors, 0);
}

#endif /* OBJECT_FORMAT_ELF */

#else /* defined(INIT_SECTION_ASM_OP) */

/* This case is used by the Irix 6 port, which supports named sections but
   not an SVR4-style .fini section.  __do_global_dtors can be non-static
   in this case because the -fini switch to ld binds strongly.  */
static func_ptr __DTOR_LIST__[];
void
__do_global_dtors ()
{
  func_ptr *p;
  for (p = __DTOR_LIST__ + 1; *p; p++)
    (*p) ();
}

#endif /* defined(INIT_SECTION_ASM_OP) */

/* Force cc1 to switch to .data section.  */
static func_ptr force_to_data[0] = { };

/* NOTE:  In order to be able to support SVR4 shared libraries, we arrange
   to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__,
   __DTOR_END__ } per root executable and also one set of these symbols
   per shared library.  So in any given whole process image, we may have
   multiple definitions of each of these symbols.  In order to prevent
   these definitions from conflicting with one another, and in order to
   ensure that the proper lists are used for the initialization/finalization
   of each individual shared library (respectively), we give these symbols
   only internal (i.e. `static') linkage, and we also make it a point to
   refer to only the __CTOR_END__ symbol in crtend.o and the __DTOR_LIST__
   symbol in crtbegin.o, where they are defined.  */

/* The -1 is a flag to __do_global_[cd]tors
   indicating that this table does not start with a count of elements.  */
#ifdef CTOR_LIST_BEGIN
CTOR_LIST_BEGIN;
#else
asm (CTORS_SECTION_ASM_OP);	/* cc1 doesn't know that we are switching! */
STATIC func_ptr __CTOR_LIST__[1] = { (func_ptr) (-1) };
#endif

#ifdef DTOR_LIST_BEGIN
DTOR_LIST_BEGIN;
#else
asm (DTORS_SECTION_ASM_OP);	/* cc1 doesn't know that we are switching! */
STATIC func_ptr __DTOR_LIST__[1] = { (func_ptr) (-1) };
#endif

#endif /* defined(CRT_BEGIN) */

#ifdef CRT_END

#ifdef INIT_SECTION_ASM_OP

#ifdef OBJECT_FORMAT_ELF

static func_ptr __CTOR_END__[];
static void
__do_global_ctors_aux ()
{
  func_ptr *p;
  for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
    (*p) ();
}

/* Stick a call to __do_global_ctors_aux into the .init section.  */

static void
init_dummy ()
{
  asm (INIT_SECTION_ASM_OP);
  __do_global_ctors_aux ();
#ifdef FORCE_INIT_SECTION_ALIGN
  FORCE_INIT_SECTION_ALIGN;
#endif
  asm (TEXT_SECTION_ASM_OP);

/* This is a kludge. The i386 Linux dynamic linker needs ___brk_addr,
   __environ and atexit (). We have to make sure they are in the .dynsym
   section. We accomplish it by making a dummy call here. This
   code is never reached.  */
 
#if defined(__linux__) && defined(__PIC__) && defined(__i386__)
  {
    extern void *___brk_addr;
    extern char **__environ;

    ___brk_addr = __environ;
    atexit ();
  }
#endif
}

#else  /* OBJECT_FORMAT_ELF */

/* Stick the real initialization code, followed by a normal sort of
   function epilogue at the very end of the .init section for this
   entire root executable file or for this entire shared library file.

   Note that we use some tricks here to get *just* the body and just
   a function epilogue (but no function prologue) into the .init
   section of the crtend.o file.  Specifically, we switch to the .text
   section, start to define a function, and then we switch to the .init
   section just before the body code.

   Earlier on, we put the corresponding function prologue into the .init
   section of the crtbegin.o file (which will be linked in first).

   Note that we want to invoke all constructors for C++ file-scope static-
   storage objects AFTER any other possible initialization actions which
   may be performed by the code in the .init section contributions made by
   other libraries, etc.  That's because those other initializations may
   include setup operations for very primitive things (e.g. initializing
   the state of the floating-point coprocessor, etc.) which should be done
   before we start to execute any of the user's code.  */

static void
__do_global_ctors_aux ()	/* prologue goes in .text section */
{
  asm (INIT_SECTION_ASM_OP);
  DO_GLOBAL_CTORS_BODY;
  ON_EXIT (__do_global_dtors, 0);
}				/* epilogue and body go in .init section */

#endif /* OBJECT_FORMAT_ELF */

#else /* defined(INIT_SECTION_ASM_OP) */

/* This case is used by the Irix 6 port, which supports named sections but
   not an SVR4-style .init section.  __do_global_ctors can be non-static
   in this case because the -init switch to ld binds strongly.  */
static func_ptr __CTOR_END__[];
void
__do_global_ctors ()
{
  func_ptr *p;
  for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
    (*p) ();
}

#endif /* defined(INIT_SECTION_ASM_OP) */

/* Force cc1 to switch to .data section.  */
static func_ptr force_to_data[0] = { };

/* Put a word containing zero at the end of each of our two lists of function
   addresses.  Note that the words defined here go into the .ctors and .dtors
   sections of the crtend.o file, and since that file is always linked in
   last, these words naturally end up at the very ends of the two lists
   contained in these two sections.  */

#ifdef CTOR_LIST_END
CTOR_LIST_END;
#else
asm (CTORS_SECTION_ASM_OP);	/* cc1 doesn't know that we are switching! */
STATIC func_ptr __CTOR_END__[1] = { (func_ptr) 0 };
#endif

#ifdef DTOR_LIST_END
DTOR_LIST_END;
#else
asm (DTORS_SECTION_ASM_OP);	/* cc1 doesn't know that we are switching! */
STATIC func_ptr __DTOR_END__[1] = { (func_ptr) 0 };
#endif

#endif /* defined(CRT_END) */
Commit	Line	Data
9d13f5c4	1	/* Specialized bits of code needed to support construction and
9d13f5c4	2	destruction of file-scope objects in C++ code.
31dcf09a	3	Copyright (C) 1991, 1994, 1995, 1996 Free Software Foundation, Inc.
31dcf09a	4	Contributed by Ron Guilmette (rfg@monkeys.com).
9d13f5c4	5
	6	This file is part of GNU CC.
	7
	8	GNU CC is free software; you can redistribute it and/or modify
	9	it under the terms of the GNU General Public License as published by
	10	the Free Software Foundation; either version 2, or (at your option)
	11	any later version.
	12
	13	GNU CC is distributed in the hope that it will be useful,
	14	but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	GNU General Public License for more details.
	17
	18	You should have received a copy of the GNU General Public License
	19	along with GNU CC; see the file COPYING. If not, write to
8d62a21c	20	the Free Software Foundation, 59 Temple Place - Suite 330,
8d62a21c	21	Boston, MA 02111-1307, USA. */
9d13f5c4	22
	23	/* As a special exception, if you link this library with files
	24	compiled with GCC to produce an executable, this does not cause
	25	the resulting executable to be covered by the GNU General Public License.
	26	This exception does not however invalidate any other reasons why
	27	the executable file might be covered by the GNU General Public License. */
	28
	29	/* This file is a bit like libgcc1.c/libgcc2.c in that it is compiled
	30	multiple times and yields multiple .o files.
	31
	32	This file is useful on target machines where the object file format
	33	supports multiple "user-defined" sections (e.g. COFF, ELF, ROSE). On
	34	such systems, this file allows us to avoid running collect (or any
	35	other such slow and painful kludge). Additionally, if the target
	36	system supports a .init section, this file allows us to support the
	37	linking of C++ code with a non-C++ main program.
	38
	39	Note that if INIT_SECTION_ASM_OP is defined in the tm.h file, then
	40	this file will make use of the .init section. If that symbol is
	41	not defined however, then the .init section will not be used.
	42
5dd605c6	43	Currently, only ELF and COFF are supported. It is likely however that
	44	ROSE could also be supported, if someone was willing to do the work to
	45	make whatever (small?) adaptations are needed. (Some work may be
	46	needed on the ROSE assembler and linker also.)
9d13f5c4	47
	48	This file must be compiled with gcc. */
	49
	50	/* It is incorrect to include config.h here, because this file is being
	51	compiled for the target, and hence definitions concerning only the host
	52	do not apply. */
	53
	54	#include "tm.h"
	55
b7c87ff2	56	/* Provide default definitions for the pseudo-ops used to switch to the
	57	.ctors and .dtors sections.
	58
	59	Note that we want to give these sections the SHF_WRITE attribute
	60	because these sections will actually contain data (i.e. tables of
	61	addresses of functions in the current root executable or shared library
	62	file) and, in the case of a shared library, the relocatable addresses
	63	will have to be properly resolved/relocated (and then written into) by
	64	the dynamic linker when it actually attaches the given shared library
	65	to the executing process. (Note that on SVR4, you may wish to use the
	66	`-z text' option to the ELF linker, when building a shared library, as
	67	an additional check that you are doing everything right. But if you do
	68	use the `-z text' option when building a shared library, you will get
	69	errors unless the .ctors and .dtors sections are marked as writable
	70	via the SHF_WRITE attribute.) */
	71
9d13f5c4	72	#ifndef CTORS_SECTION_ASM_OP
b7c87ff2	73	#define CTORS_SECTION_ASM_OP ".section\t.ctors,\"aw\""
9d13f5c4	74	#endif
9d13f5c4	75	#ifndef DTORS_SECTION_ASM_OP
b7c87ff2	76	#define DTORS_SECTION_ASM_OP ".section\t.dtors,\"aw\""
9d13f5c4	77	#endif
9d13f5c4	78
b7c87ff2	79	#ifdef OBJECT_FORMAT_ELF
	80
	81	/* Declare a pointer to void function type. */
	82	typedef void (*func_ptr) (void);
	83	#define STATIC static
	84
	85	#else /* OBJECT_FORMAT_ELF */
	86
9d13f5c4	87	#include "gbl-ctors.h"
	88
	89	#ifndef ON_EXIT
	90	#define ON_EXIT(a, b)
	91	#endif
b7c87ff2	92	#define STATIC
	93
	94	#endif /* OBJECT_FORMAT_ELF */
9d13f5c4	95
	96	#ifdef CRT_BEGIN
	97
	98	#ifdef INIT_SECTION_ASM_OP
	99
b7c87ff2	100	#ifdef OBJECT_FORMAT_ELF
	101
	102	/* Run all the global destructors on exit from the program. */
	103
	104	/* Some systems place the number of pointers in the first word of the
	105	table. On SVR4 however, that word is -1. In all cases, the table is
	106	null-terminated. On SVR4, we start from the beginning of the list and
	107	invoke each per-compilation-unit destructor routine in order
	108	until we find that null.
	109
	110	Note that this function MUST be static. There will be one of these
	111	functions in each root executable and one in each shared library, but
	112	although they all have the same code, each one is unique in that it
	113	refers to one particular associated `__DTOR_LIST__' which belongs to the
	114	same particular root executable or shared library file. */
	115
	116	static func_ptr __DTOR_LIST__[];
	117	static void
	118	__do_global_dtors_aux ()
	119	{
	120	func_ptr *p;
	121	for (p = __DTOR_LIST__ + 1; *p; p++)
	122	(*p) ();
	123	}
	124
	125	/* Stick a call to __do_global_dtors_aux into the .fini section. */
a92771b8	126
b7c87ff2	127	static void
	128	fini_dummy ()
	129	{
	130	asm (FINI_SECTION_ASM_OP);
	131	__do_global_dtors_aux ();
	132	#ifdef FORCE_FINI_SECTION_ALIGN
	133	FORCE_FINI_SECTION_ALIGN;
	134	#endif
	135	asm (TEXT_SECTION_ASM_OP);
	136	}
	137
	138	#else /* OBJECT_FORMAT_ELF */
	139
b13ae905	140	/* The function __do_global_ctors_aux is compiled twice (once in crtbegin.o
d8fa92ab	141	and once in crtend.o). It must be declared static to avoid a link
b13ae905	142	error. Here, we define __do_global_ctors as an externally callable
	143	function. It is externally callable so that __main can invoke it when
	144	INVOKE__main is defined. This has the additional effect of forcing cc1
	145	to switch to the .text section. */
a92771b8	146
ee45242a	147	static void __do_global_ctors_aux ();
84b64a19	148	void __do_global_ctors ()
	149	{
	150	#ifdef INVOKE__main /* If __main won't actually call __do_global_ctors
	151	then it doesn't matter what's inside the function.
	152	The inside of __do_global_ctors_aux is called
	153	automatically in that case.
	154	And the Alliant fx2800 linker crashes
	155	on this reference. So prevent the crash. */
	156	__do_global_ctors_aux ();
	157	#endif
	158	}
9d13f5c4	159
	160	asm (INIT_SECTION_ASM_OP); /* cc1 doesn't know that we are switching! */
	161
3c67709e	162	/* On some svr4 systems, the initial .init section preamble code provided in
	163	crti.o may do something, such as bump the stack, which we have to
	164	undo before we reach the function prologue code for __do_global_ctors
	165	(directly below). For such systems, define the macro INIT_SECTION_PREAMBLE
a92771b8	166	to expand into the code needed to undo the actions of the crti.o file. */
3c67709e	167
	168	#ifdef INIT_SECTION_PREAMBLE
	169	INIT_SECTION_PREAMBLE;
	170	#endif
	171
9d13f5c4	172	/* A routine to invoke all of the global constructors upon entry to the
	173	program. We put this into the .init section (for systems that have
	174	such a thing) so that we can properly perform the construction of
	175	file-scope static-storage C++ objects within shared libraries. */
	176
	177	static void
b13ae905	178	__do_global_ctors_aux () /* prologue goes in .init section */
9d13f5c4	179	{
635d52b7	180	#ifdef FORCE_INIT_SECTION_ALIGN
	181	FORCE_INIT_SECTION_ALIGN; /* Explicit align before switch to .text */
	182	#endif
9d13f5c4	183	asm (TEXT_SECTION_ASM_OP); /* don't put epilogue and body in .init */
	184	DO_GLOBAL_CTORS_BODY;
	185	ON_EXIT (__do_global_dtors, 0);
	186	}
	187
b7c87ff2	188	#endif /* OBJECT_FORMAT_ELF */
8313a782	189
	190	#else /* defined(INIT_SECTION_ASM_OP) */
	191
	192	/* This case is used by the Irix 6 port, which supports named sections but
	193	not an SVR4-style .fini section. __do_global_dtors can be non-static
	194	in this case because the -fini switch to ld binds strongly. */
	195	static func_ptr __DTOR_LIST__[];
	196	void
	197	__do_global_dtors ()
	198	{
	199	func_ptr *p;
	200	for (p = __DTOR_LIST__ + 1; *p; p++)
	201	(*p) ();
	202	}
	203
9d13f5c4	204	#endif /* defined(INIT_SECTION_ASM_OP) */
	205
	206	/* Force cc1 to switch to .data section. */
	207	static func_ptr force_to_data[0] = { };
	208
b7c87ff2	209	/* NOTE: In order to be able to support SVR4 shared libraries, we arrange
	210	to have one set of symbols { __CTOR_LIST__, __DTOR_LIST__, __CTOR_END__,
	211	__DTOR_END__ } per root executable and also one set of these symbols
	212	per shared library. So in any given whole process image, we may have
	213	multiple definitions of each of these symbols. In order to prevent
	214	these definitions from conflicting with one another, and in order to
	215	ensure that the proper lists are used for the initialization/finalization
	216	of each individual shared library (respectively), we give these symbols
	217	only internal (i.e. `static') linkage, and we also make it a point to
	218	refer to only the __CTOR_END__ symbol in crtend.o and the __DTOR_LIST__
	219	symbol in crtbegin.o, where they are defined. */
	220
9d13f5c4	221	/* The -1 is a flag to __do_global_[cd]tors
9d13f5c4	222	indicating that this table does not start with a count of elements. */
b13ae905	223	#ifdef CTOR_LIST_BEGIN
	224	CTOR_LIST_BEGIN;
	225	#else
9d13f5c4	226	asm (CTORS_SECTION_ASM_OP); /* cc1 doesn't know that we are switching! */
b7c87ff2	227	STATIC func_ptr __CTOR_LIST__[1] = { (func_ptr) (-1) };
b13ae905	228	#endif
9d13f5c4	229
b13ae905	230	#ifdef DTOR_LIST_BEGIN
	231	DTOR_LIST_BEGIN;
	232	#else
9d13f5c4	233	asm (DTORS_SECTION_ASM_OP); /* cc1 doesn't know that we are switching! */
b7c87ff2	234	STATIC func_ptr __DTOR_LIST__[1] = { (func_ptr) (-1) };
b13ae905	235	#endif
9d13f5c4	236
	237	#endif /* defined(CRT_BEGIN) */
	238
	239	#ifdef CRT_END
	240
	241	#ifdef INIT_SECTION_ASM_OP
	242
b7c87ff2	243	#ifdef OBJECT_FORMAT_ELF
9d13f5c4	244
b7c87ff2	245	static func_ptr __CTOR_END__[];
	246	static void
	247	__do_global_ctors_aux ()
	248	{
	249	func_ptr *p;
	250	for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
	251	(*p) ();
	252	}
	253
	254	/* Stick a call to __do_global_ctors_aux into the .init section. */
a92771b8	255
b7c87ff2	256	static void
	257	init_dummy ()
	258	{
	259	asm (INIT_SECTION_ASM_OP);
	260	__do_global_ctors_aux ();
	261	#ifdef FORCE_INIT_SECTION_ALIGN
	262	FORCE_INIT_SECTION_ALIGN;
	263	#endif
	264	asm (TEXT_SECTION_ASM_OP);
baf8c510	265
31dcf09a	266	/* This is a kludge. The i386 Linux dynamic linker needs ___brk_addr,
	267	__environ and atexit (). We have to make sure they are in the .dynsym
	268	section. We accomplish it by making a dummy call here. This
a92771b8	269	code is never reached. */
baf8c510	270
31dcf09a	271	#if defined(__linux__) && defined(__PIC__) && defined(__i386__)
baf8c510	272	{
	273	extern void *___brk_addr;
	274	extern char **__environ;
	275
	276	___brk_addr = __environ;
	277	atexit ();
	278	}
	279	#endif
b7c87ff2	280	}
	281
	282	#else /* OBJECT_FORMAT_ELF */
	283
	284	/* Stick the real initialization code, followed by a normal sort of
	285	function epilogue at the very end of the .init section for this
	286	entire root executable file or for this entire shared library file.
	287
	288	Note that we use some tricks here to get just the body and just
	289	a function epilogue (but no function prologue) into the .init
c3418f42	290	section of the crtend.o file. Specifically, we switch to the .text
b7c87ff2	291	section, start to define a function, and then we switch to the .init
	292	section just before the body code.
	293
	294	Earlier on, we put the corresponding function prologue into the .init
	295	section of the crtbegin.o file (which will be linked in first).
	296
	297	Note that we want to invoke all constructors for C++ file-scope static-
	298	storage objects AFTER any other possible initialization actions which
	299	may be performed by the code in the .init section contributions made by
	300	other libraries, etc. That's because those other initializations may
	301	include setup operations for very primitive things (e.g. initializing
	302	the state of the floating-point coprocessor, etc.) which should be done
a92771b8	303	before we start to execute any of the user's code. */
9d13f5c4	304
9d13f5c4	305	static void
b13ae905	306	__do_global_ctors_aux () /* prologue goes in .text section */
9d13f5c4	307	{
	308	asm (INIT_SECTION_ASM_OP);
	309	DO_GLOBAL_CTORS_BODY;
	310	ON_EXIT (__do_global_dtors, 0);
	311	} /* epilogue and body go in .init section */
	312
b7c87ff2	313	#endif /* OBJECT_FORMAT_ELF */
b7c87ff2	314
8313a782	315	#else /* defined(INIT_SECTION_ASM_OP) */
	316
	317	/* This case is used by the Irix 6 port, which supports named sections but
	318	not an SVR4-style .init section. __do_global_ctors can be non-static
	319	in this case because the -init switch to ld binds strongly. */
	320	static func_ptr __CTOR_END__[];
	321	void
	322	__do_global_ctors ()
	323	{
	324	func_ptr *p;
	325	for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--)
	326	(*p) ();
	327	}
	328
9d13f5c4	329	#endif /* defined(INIT_SECTION_ASM_OP) */
	330
	331	/* Force cc1 to switch to .data section. */
	332	static func_ptr force_to_data[0] = { };
	333
b7c87ff2	334	/* Put a word containing zero at the end of each of our two lists of function
	335	addresses. Note that the words defined here go into the .ctors and .dtors
	336	sections of the crtend.o file, and since that file is always linked in
	337	last, these words naturally end up at the very ends of the two lists
	338	contained in these two sections. */
	339
b13ae905	340	#ifdef CTOR_LIST_END
	341	CTOR_LIST_END;
	342	#else
9d13f5c4	343	asm (CTORS_SECTION_ASM_OP); /* cc1 doesn't know that we are switching! */
b7c87ff2	344	STATIC func_ptr __CTOR_END__[1] = { (func_ptr) 0 };
b13ae905	345	#endif
9d13f5c4	346
b13ae905	347	#ifdef DTOR_LIST_END
	348	DTOR_LIST_END;
	349	#else
9d13f5c4	350	asm (DTORS_SECTION_ASM_OP); /* cc1 doesn't know that we are switching! */
b7c87ff2	351	STATIC func_ptr __DTOR_END__[1] = { (func_ptr) 0 };
b13ae905	352	#endif
9d13f5c4	353
9d13f5c4	354	#endif /* defined(CRT_END) */