/* Specialized bits of code needed to support construction and destruction of file-scope objects in C++ code. Copyright (C) 1991, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. Contributed by Ron Guilmette (rfg@monkeys.com). This file is part of GCC. GCC 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. In addition to the permissions in the GNU General Public License, the Free Software Foundation gives you unlimited permission to link the compiled version of this file into combinations with other programs, and to distribute those combinations without any restriction coming from the use of this file. (The General Public License restrictions do apply in other respects; for example, they cover modification of the file, and distribution when not linked into a combine executable.) GCC 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 GCC; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /* This file is a bit like 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. */ #define IN_LIBGCC2 /* We include auto-host.h here to get HAVE_GAS_HIDDEN. This is supposedly valid even though this is a "target" file. */ #include "auto-host.h" #include "tconfig.h" #include "tsystem.h" #include "coretypes.h" #include "tm.h" #include "unwind-dw2-fde.h" #ifndef FORCE_CODE_SECTION_ALIGN # define FORCE_CODE_SECTION_ALIGN #endif #ifndef CRT_CALL_STATIC_FUNCTION # define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC) \ static void __attribute__((__used__)) \ call_ ## FUNC (void) \ { \ asm (SECTION_OP); \ FUNC (); \ FORCE_CODE_SECTION_ALIGN \ asm (TEXT_SECTION_ASM_OP); \ } #endif #if defined(OBJECT_FORMAT_ELF) && defined(HAVE_LD_EH_FRAME_HDR) \ && !defined(inhibit_libc) && !defined(CRTSTUFFT_O) \ && defined(__GLIBC__) && __GLIBC__ >= 2 #include <link.h> # if (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \ || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG))) # define USE_PT_GNU_EH_FRAME # endif #endif #if defined(EH_FRAME_SECTION_NAME) && !defined(USE_PT_GNU_EH_FRAME) # define USE_EH_FRAME_REGISTRY #endif #if defined(EH_FRAME_SECTION_NAME) && EH_TABLES_CAN_BE_READ_ONLY # define EH_FRAME_SECTION_CONST const #else # define EH_FRAME_SECTION_CONST #endif /* We do not want to add the weak attribute to the declarations of these routines in unwind-dw2-fde.h because that will cause the definition of these symbols to be weak as well. This exposes a core issue, how to handle creating weak references vs how to create weak definitions. Either we have to have the definition of TARGET_WEAK_ATTRIBUTE be conditional in the shared header files or have a second declaration if we want a function's references to be weak, but not its definition. Making TARGET_WEAK_ATTRIBUTE conditional seems like a good solution until one thinks about scaling to larger problems -- i.e., the condition under which TARGET_WEAK_ATTRIBUTE is active will eventually get far too complicated. So, we take an approach similar to #pragma weak -- we have a second declaration for functions that we want to have weak references. Neither way is particularly good. */ /* References to __register_frame_info and __deregister_frame_info should be weak in this file if at all possible. */ extern void __register_frame_info (const void *, struct object *) TARGET_ATTRIBUTE_WEAK; extern void __register_frame_info_bases (const void *, struct object *, void *, void *) TARGET_ATTRIBUTE_WEAK; extern void *__deregister_frame_info (const void *) TARGET_ATTRIBUTE_WEAK; extern void *__deregister_frame_info_bases (const void *) TARGET_ATTRIBUTE_WEAK; extern void __do_global_ctors_1 (void); /* Likewise for _Jv_RegisterClasses. */ extern void _Jv_RegisterClasses (void *) TARGET_ATTRIBUTE_WEAK; #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" #define STATIC #endif /* OBJECT_FORMAT_ELF */ #ifdef CRT_BEGIN /* 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; #elif defined(CTORS_SECTION_ASM_OP) /* Hack: force cc1 to switch to .data section early, so that assembling __CTOR_LIST__ does not undo our behind-the-back change to .ctors. */ static func_ptr force_to_data[1] __attribute__ ((__unused__)) = { }; asm (CTORS_SECTION_ASM_OP); STATIC func_ptr __CTOR_LIST__[1] __attribute__ ((__unused__, aligned(sizeof(func_ptr)))) = { (func_ptr) (-1) }; #else STATIC func_ptr __CTOR_LIST__[1] __attribute__ ((__unused__, section(".ctors"), aligned(sizeof(func_ptr)))) = { (func_ptr) (-1) }; #endif /* __CTOR_LIST__ alternatives */ #ifdef DTOR_LIST_BEGIN DTOR_LIST_BEGIN; #elif defined(DTORS_SECTION_ASM_OP) asm (DTORS_SECTION_ASM_OP); STATIC func_ptr __DTOR_LIST__[1] __attribute__ ((aligned(sizeof(func_ptr)))) = { (func_ptr) (-1) }; #else STATIC func_ptr __DTOR_LIST__[1] __attribute__((section(".dtors"), aligned(sizeof(func_ptr)))) = { (func_ptr) (-1) }; #endif /* __DTOR_LIST__ alternatives */ #ifdef USE_EH_FRAME_REGISTRY /* Stick a label at the beginning of the frame unwind info so we can register and deregister it with the exception handling library code. */ STATIC EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[] __attribute__((section(EH_FRAME_SECTION_NAME), aligned(4))) = { }; #endif /* USE_EH_FRAME_REGISTRY */ #ifdef JCR_SECTION_NAME /* Stick a label at the beginning of the java class registration info so we can register them properly. */ STATIC void *__JCR_LIST__[] __attribute__ ((unused, section(JCR_SECTION_NAME), aligned(sizeof(void*)))) = { }; #endif /* JCR_SECTION_NAME */ #ifdef INIT_SECTION_ASM_OP #ifdef OBJECT_FORMAT_ELF /* Declare the __dso_handle variable. It should have a unique value in every shared-object; in a main program its value is zero. The object should in any case be protected. This means the instance in one DSO or the main program is not used in another object. The dynamic linker takes care of this. */ #ifdef HAVE_GAS_HIDDEN extern void *__dso_handle __attribute__ ((__visibility__ ("hidden"))); #endif #ifdef CRTSTUFFS_O void *__dso_handle = &__dso_handle; #else void *__dso_handle = 0; #endif /* The __cxa_finalize function may not be available so we use only a weak declaration. */ extern void __cxa_finalize (void *) TARGET_ATTRIBUTE_WEAK; /* 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. On some systems, this routine is run more than once from the .fini, when exit is called recursively, so we arrange to remember where in the list we left off processing, and we resume at that point, should we be re-invoked. */ static void __attribute__((used)) __do_global_dtors_aux (void) { static func_ptr *p = __DTOR_LIST__ + 1; static _Bool completed; func_ptr f; if (__builtin_expect (completed, 0)) return; #ifdef CRTSTUFFS_O if (__cxa_finalize) __cxa_finalize (__dso_handle); #endif while ((f = *p)) { p++; f (); } #ifdef USE_EH_FRAME_REGISTRY #ifdef CRT_GET_RFIB_DATA /* If we used the new __register_frame_info_bases interface, make sure that we deregister from the same place. */ if (__deregister_frame_info_bases) __deregister_frame_info_bases (__EH_FRAME_BEGIN__); #else if (__deregister_frame_info) __deregister_frame_info (__EH_FRAME_BEGIN__); #endif #endif completed = 1; } /* Stick a call to __do_global_dtors_aux into the .fini section. */ CRT_CALL_STATIC_FUNCTION (FINI_SECTION_ASM_OP, __do_global_dtors_aux) #if defined(USE_EH_FRAME_REGISTRY) || defined(JCR_SECTION_NAME) /* Stick a call to __register_frame_info into the .init section. For some reason calls with no arguments work more reliably in .init, so stick the call in another function. */ static void __attribute__((used)) frame_dummy (void) { #ifdef USE_EH_FRAME_REGISTRY static struct object object; #ifdef CRT_GET_RFIB_DATA void *tbase, *dbase; tbase = 0; CRT_GET_RFIB_DATA (dbase); if (__register_frame_info_bases) __register_frame_info_bases (__EH_FRAME_BEGIN__, &object, tbase, dbase); #else if (__register_frame_info) __register_frame_info (__EH_FRAME_BEGIN__, &object); #endif /* CRT_GET_RFIB_DATA */ #endif /* USE_EH_FRAME_REGISTRY */ #ifdef JCR_SECTION_NAME if (__JCR_LIST__[0]) { void (*register_classes) (void *) = _Jv_RegisterClasses; __asm ("" : "+r" (register_classes)); if (register_classes) register_classes (__JCR_LIST__); } #endif /* JCR_SECTION_NAME */ } CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, frame_dummy) #endif /* USE_EH_FRAME_REGISTRY || JCR_SECTION_NAME */ #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); void __do_global_ctors (void) { #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! */ /* 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 __attribute__((used)) __do_global_ctors_aux (void) /* prologue goes in .init section */ { FORCE_CODE_SECTION_ALIGN /* explicit align before switch to .text */ asm (TEXT_SECTION_ASM_OP); /* don't put epilogue and body in .init */ DO_GLOBAL_CTORS_BODY; atexit (__do_global_dtors); } #endif /* OBJECT_FORMAT_ELF */ #elif defined(HAS_INIT_SECTION) /* ! INIT_SECTION_ASM_OP */ extern void __do_global_dtors (void); /* 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 we protect it with -hidden_symbol. */ void __do_global_dtors (void) { func_ptr *p, f; for (p = __DTOR_LIST__ + 1; (f = *p); p++) f (); #ifdef USE_EH_FRAME_REGISTRY if (__deregister_frame_info) __deregister_frame_info (__EH_FRAME_BEGIN__); #endif } #if defined(USE_EH_FRAME_REGISTRY) || defined(JCR_SECTION_NAME) /* A helper function for __do_global_ctors, which is in crtend.o. Here in crtbegin.o, we can reference a couple of symbols not visible there. Plus, since we're before libgcc.a, we have no problems referencing functions from there. */ void __do_global_ctors_1(void) { #ifdef USE_EH_FRAME_REGISTRY static struct object object; if (__register_frame_info) __register_frame_info (__EH_FRAME_BEGIN__, &object); #endif #ifdef JCR_SECTION_NAME if (__JCR_LIST__[0]) { void (*register_classes) (void *) = _Jv_RegisterClasses; __asm ("" : "+r" (register_classes)); if (register_classes) register_classes (__JCR_LIST__); } #endif } #endif /* USE_EH_FRAME_REGISTRY || JCR_SECTION_NAME */ #else /* ! INIT_SECTION_ASM_OP && ! HAS_INIT_SECTION */ #error "What are you doing with crtstuff.c, then?" #endif #elif defined(CRT_END) /* ! CRT_BEGIN */ /* 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; #elif defined(CTORS_SECTION_ASM_OP) /* Hack: force cc1 to switch to .data section early, so that assembling __CTOR_LIST__ does not undo our behind-the-back change to .ctors. */ static func_ptr force_to_data[1] __attribute__ ((__unused__)) = { }; asm (CTORS_SECTION_ASM_OP); STATIC func_ptr __CTOR_END__[1] __attribute__((aligned(sizeof(func_ptr)))) = { (func_ptr) 0 }; #else STATIC func_ptr __CTOR_END__[1] __attribute__((section(".ctors"), aligned(sizeof(func_ptr)))) = { (func_ptr) 0 }; #endif #ifdef DTOR_LIST_END DTOR_LIST_END; #elif defined(DTORS_SECTION_ASM_OP) asm (DTORS_SECTION_ASM_OP); STATIC func_ptr __DTOR_END__[1] __attribute__ ((unused, aligned(sizeof(func_ptr)))) = { (func_ptr) 0 }; #else STATIC func_ptr __DTOR_END__[1] __attribute__((unused, section(".dtors"), aligned(sizeof(func_ptr)))) = { (func_ptr) 0 }; #endif #ifdef EH_FRAME_SECTION_NAME /* Terminate the frame unwind info section with a 4byte 0 as a sentinel; this would be the 'length' field in a real FDE. */ # if __INT_MAX__ == 2147483647 typedef int int32; # elif __LONG_MAX__ == 2147483647 typedef long int32; # elif __SHRT_MAX__ == 2147483647 typedef short int32; # else # error "Missing a 4 byte integer" # endif STATIC EH_FRAME_SECTION_CONST int32 __FRAME_END__[] __attribute__ ((unused, section(EH_FRAME_SECTION_NAME), aligned(sizeof(int32)))) = { 0 }; #endif /* EH_FRAME_SECTION_NAME */ #ifdef JCR_SECTION_NAME /* Null terminate the .jcr section array. */ STATIC void *__JCR_END__[1] __attribute__ ((unused, section(JCR_SECTION_NAME), aligned(sizeof(void *)))) = { 0 }; #endif /* JCR_SECTION_NAME */ #ifdef INIT_SECTION_ASM_OP #ifdef OBJECT_FORMAT_ELF static void __attribute__((used)) __do_global_ctors_aux (void) { 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. */ CRT_CALL_STATIC_FUNCTION (INIT_SECTION_ASM_OP, __do_global_ctors_aux) #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 (void) /* prologue goes in .text section */ { asm (INIT_SECTION_ASM_OP); DO_GLOBAL_CTORS_BODY; atexit (__do_global_dtors); } /* epilogue and body go in .init section */ FORCE_CODE_SECTION_ALIGN asm (TEXT_SECTION_ASM_OP); #endif /* OBJECT_FORMAT_ELF */ #elif defined(HAS_INIT_SECTION) /* ! INIT_SECTION_ASM_OP */ extern void __do_global_ctors (void); /* 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 we protect it with -hidden_symbol. */ void __do_global_ctors (void) { func_ptr *p; #if defined(USE_EH_FRAME_REGISTRY) || defined(JCR_SECTION_NAME) __do_global_ctors_1(); #endif for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--) (*p) (); } #else /* ! INIT_SECTION_ASM_OP && ! HAS_INIT_SECTION */ #error "What are you doing with crtstuff.c, then?" #endif #else /* ! CRT_BEGIN && ! CRT_END */ #error "One of CRT_BEGIN or CRT_END must be defined." #endif