/* Specialized bits of code needed to support construction and
destruction of file-scope objects in C++ code.
-
- Written by Ron Guilmette (rfg@ncd.com) with help from Richard Stallman.
-
-Copyright (C) 1991 Free Software Foundation, Inc.
+ Copyright (C) 1991, 1994, 1995, 1996 Free Software Foundation, Inc.
+ Contributed by Ron Guilmette (rfg@monkeys.com).
This file is part of GNU CC.
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, 675 Mass Ave, Cambridge, MA 02139, USA. */
+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
#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,\"a\",@progbits"
+#define CTORS_SECTION_ASM_OP ".section\t.ctors,\"aw\""
#endif
#ifndef DTORS_SECTION_ASM_OP
-#define DTORS_SECTION_ASM_OP ".section\t.dtors,\"a\",@progbits"
+#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 ()
{
asm (INIT_SECTION_ASM_OP); /* cc1 doesn't know that we are switching! */
-/* On some svr4 systems, the .init section preamble code provided in
- crti.o may do some evil things 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. */
-
+/* 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
ON_EXIT (__do_global_dtors, 0);
}
+#endif /* OBJECT_FORMAT_ELF */
#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! */
-func_ptr __CTOR_LIST__[1] = { (func_ptr) (-1) };
+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! */
-func_ptr __DTOR_LIST__[1] = { (func_ptr) (-1) };
+STATIC func_ptr __DTOR_LIST__[1] = { (func_ptr) (-1) };
#endif
#endif /* defined(CRT_BEGIN) */
#ifdef INIT_SECTION_ASM_OP
-/* 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.
+#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) ();
+}
- This must be virtually identical to the one above so that we can
- insure that the function prologue from the one above works correctly
- with the epilogue from this one. (They will both go into the .init
- section as the first and last things (respectively) that the linker
- will put in that section.)
-*/
+/* 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 */
ON_EXIT (__do_global_dtors, 0);
} /* epilogue and body go in .init section */
+#endif /* OBJECT_FORMAT_ELF */
+
#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! */
-func_ptr __CTOR_END__[1] = { (func_ptr) 0 };
+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! */
-func_ptr __DTOR_END__[1] = { (func_ptr) 0 };
+STATIC func_ptr __DTOR_END__[1] = { (func_ptr) 0 };
#endif
#endif /* defined(CRT_END) */
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