xref: /freebsd/lib/csu/common/crtbegin.c (revision 6ee34bca48a9e0867d46b24a78855e225d46ddda)

/*-
 * SPDX-License-Identifier: BSD-1-Clause
 *
 * Copyright 2018 Andrew Turner
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/param.h>

#include "crt.h"

typedef void (*crt_func)(void);

extern void *__dso_handle __hidden;

#ifndef SHARED
void *__dso_handle = 0;
#else
void *__dso_handle = &__dso_handle;
void __cxa_finalize(void *) __weak_symbol;

/*
 * Call __cxa_finalize with the dso handle in shared objects.
 * When we have ctors/dtors call from the dtor handler before calling
 * any dtors, otherwise use a destructor.
 */
#ifndef HAVE_CTORS
__attribute__((destructor))
#endif
static void
run_cxa_finalize(void)
{

	if (__cxa_finalize != NULL)
		__cxa_finalize(__dso_handle);
}
#endif

/*
 * On some architectures and toolchains we may need to call the .dtors.
 * These are called in the order they are in the ELF file.
 */
#ifdef HAVE_CTORS
static void __do_global_dtors_aux(void) __used;

static crt_func __CTOR_LIST__[] __section(".ctors") __used = {
	(crt_func)-1
};
static crt_func __DTOR_LIST__[] __section(".dtors") __used = {
	(crt_func)-1
};

extern const char startof_dtors[] __asm(".startof..dtors")
    __weak_symbol __hidden;
extern const char sizeof_dtors[] __asm(".sizeof..dtors")
    __weak_symbol __hidden;

static void
__do_global_dtors_aux(void)
{
	crt_func fn;
	uintptr_t dtors_end;
	int n;

#ifdef SHARED
	run_cxa_finalize();
#endif

	dtors_end = (uintptr_t)&startof_dtors + (uintptr_t)&sizeof_dtors;
	for (n = 1;; n++) {
		fn = __DTOR_LIST__[n];
		if (fn == (crt_func)0 || fn == (crt_func)-1 || (dtors_end > 0 &&
		    (uintptr_t)&__DTOR_LIST__[n] >= dtors_end))
			break;
		fn();
	}
}

asm (
    ".pushsection .fini		\n"
    "\t" INIT_CALL_SEQ(__do_global_dtors_aux) "\n"
    ".popsection		\n"
);
#endif

/*
 * Handler for gcj. These provide a _Jv_RegisterClasses function and fill
 * out the .jcr section. We just need to call this function with a pointer
 * to the appropriate section.
 */
extern void _Jv_RegisterClasses(void *) __weak_symbol;
static void register_classes(void) __used;

static crt_func __JCR_LIST__[] __section(".jcr") __used = { };

#ifndef CTORS_CONSTRUCTORS
__attribute__((constructor))
#endif
static void
register_classes(void)
{

	if (_Jv_RegisterClasses != NULL && __JCR_LIST__[0] != 0)
		_Jv_RegisterClasses(__JCR_LIST__);
}

/*
 * We can't use constructors when they use the .ctors section as they may be
 * placed before __CTOR_LIST__.
 */
#ifdef CTORS_CONSTRUCTORS
asm (
    ".pushsection .init		\n"
    "\t" INIT_CALL_SEQ(register_classes) "\n"
    ".popsection		\n"
);
#endif