diff options
author | Marc Espie <espie@cvs.openbsd.org> | 1999-05-26 13:38:57 +0000 |
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committer | Marc Espie <espie@cvs.openbsd.org> | 1999-05-26 13:38:57 +0000 |
commit | 0126e157b87f137fc08dc7f46f6c291b9d06ac5d (patch) | |
tree | f8555e3e504eb82b4cd3cba5cec20ae4ce8124ff /gnu/egcs/gcc/crtstuff.c | |
parent | ff8e9a4356e55ed142306c3a375fa280800abc86 (diff) |
egcs projects compiler system
Exact copy of the snapshot, except for the removal of
texinfo/
gcc/ch/
libchill/
Diffstat (limited to 'gnu/egcs/gcc/crtstuff.c')
-rw-r--r-- | gnu/egcs/gcc/crtstuff.c | 564 |
1 files changed, 564 insertions, 0 deletions
diff --git a/gnu/egcs/gcc/crtstuff.c b/gnu/egcs/gcc/crtstuff.c new file mode 100644 index 00000000000..ccebde1d2c9 --- /dev/null +++ b/gnu/egcs/gcc/crtstuff.c @@ -0,0 +1,564 @@ +/* Specialized bits of code needed to support construction and + destruction of file-scope objects in C++ code. + Copyright (C) 1991, 94, 95, 96, 97, 1998 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" +#include "defaults.h" +#include <stddef.h> +#include "frame.h" + +/* We do not want to add the weak attribute to the declarations of these + routines in frame.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 -- ie, 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 (void *, struct object *) + TARGET_ATTRIBUTE_WEAK; + +extern void *__deregister_frame_info (void *) + TARGET_ATTRIBUTE_WEAK; + +#ifndef OBJECT_FORMAT_MACHO + +/* 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 +#if !defined (EH_FRAME_SECTION_ASM_OP) && defined (DWARF2_UNWIND_INFO) && defined(ASM_OUTPUT_SECTION_NAME) +#define EH_FRAME_SECTION_ASM_OP ".section\t.eh_frame,\"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. + + 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 char __EH_FRAME_BEGIN__[]; +static func_ptr __DTOR_LIST__[]; +static void +__do_global_dtors_aux (void) +{ + static func_ptr *p = __DTOR_LIST__ + 1; + static int completed = 0; + + if (completed) + return; + + while (*p) + { + p++; + (*(p-1)) (); + } + +#ifdef EH_FRAME_SECTION_ASM_OP + if (__deregister_frame_info) + __deregister_frame_info (__EH_FRAME_BEGIN__); +#endif + completed = 1; +} + + +/* Stick a call to __do_global_dtors_aux into the .fini section. */ + +static void __attribute__ ((__unused__)) +fini_dummy (void) +{ + asm (FINI_SECTION_ASM_OP); + __do_global_dtors_aux (); +#ifdef FORCE_FINI_SECTION_ALIGN + FORCE_FINI_SECTION_ALIGN; +#endif + asm (TEXT_SECTION_ASM_OP); +} + +#ifdef EH_FRAME_SECTION_ASM_OP +/* 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 +frame_dummy (void) +{ + static struct object object; + if (__register_frame_info) + __register_frame_info (__EH_FRAME_BEGIN__, &object); +} + +static void __attribute__ ((__unused__)) +init_dummy (void) +{ + asm (INIT_SECTION_ASM_OP); + frame_dummy (); +#ifdef FORCE_INIT_SECTION_ALIGN + FORCE_INIT_SECTION_ALIGN; +#endif + asm (TEXT_SECTION_ASM_OP); +} +#endif /* EH_FRAME_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 (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! */ + +/* 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 (void) /* 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) */ + +#ifdef HAS_INIT_SECTION +/* 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. */ + +static char __EH_FRAME_BEGIN__[]; +static func_ptr __DTOR_LIST__[]; +void +__do_global_dtors (void) +{ + func_ptr *p; + for (p = __DTOR_LIST__ + 1; *p; p++) + (*p) (); + +#ifdef EH_FRAME_SECTION_ASM_OP + if (__deregister_frame_info) + __deregister_frame_info (__EH_FRAME_BEGIN__); +#endif +} + +#ifdef EH_FRAME_SECTION_ASM_OP +/* Define a function here to call __register_frame. crtend.o is linked in + after libgcc.a, and hence can't call libgcc.a functions directly. That + can lead to unresolved function references. */ +void +__frame_dummy (void) +{ + static struct object object; + if (__register_frame_info) + __register_frame_info (__EH_FRAME_BEGIN__, &object); +} +#endif +#endif + +#endif /* defined(INIT_SECTION_ASM_OP) */ + +/* Force cc1 to switch to .data section. */ +static func_ptr force_to_data[0] __attribute__ ((__unused__)) = { }; + +/* 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] __attribute__ ((__unused__)) + = { (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 + +#ifdef EH_FRAME_SECTION_ASM_OP +/* Stick a label at the beginning of the frame unwind info so we can register + and deregister it with the exception handling library code. */ + +asm (EH_FRAME_SECTION_ASM_OP); +#ifdef INIT_SECTION_ASM_OP +STATIC +#endif +char __EH_FRAME_BEGIN__[] = { }; +#endif /* EH_FRAME_SECTION_ASM_OP */ + +#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 (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. */ + +static void __attribute__ ((__unused__)) +init_dummy (void) +{ + 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 GNU/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 (void) /* 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 */ + +#ifdef FORCE_INIT_SECTION_ALIGN +FORCE_INIT_SECTION_ALIGN; +#endif + +asm (TEXT_SECTION_ASM_OP); + +#endif /* OBJECT_FORMAT_ELF */ + +#else /* defined(INIT_SECTION_ASM_OP) */ + +#ifdef HAS_INIT_SECTION +/* 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. */ +static func_ptr __CTOR_END__[]; +#ifdef EH_FRAME_SECTION_ASM_OP +extern void __frame_dummy (void); +#endif +void +__do_global_ctors (void) +{ + func_ptr *p; +#ifdef EH_FRAME_SECTION_ASM_OP + __frame_dummy (); +#endif + for (p = __CTOR_END__ - 1; *p != (func_ptr) -1; p--) + (*p) (); +} +#endif + +#endif /* defined(INIT_SECTION_ASM_OP) */ + +/* Force cc1 to switch to .data section. */ +static func_ptr force_to_data[0] __attribute__ ((__unused__)) = { }; + +/* 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] __attribute__ ((__unused__)) + = { (func_ptr) 0 }; +#endif + +#ifdef EH_FRAME_SECTION_ASM_OP +/* Terminate the frame unwind info section with a 4byte 0 as a sentinel; + this would be the 'length' field in a real FDE. */ + +typedef unsigned int ui32 __attribute__ ((mode (SI))); +asm (EH_FRAME_SECTION_ASM_OP); +STATIC ui32 __FRAME_END__[] __attribute__ ((__unused__)) = { 0 }; +#endif /* EH_FRAME_SECTION */ + +#endif /* defined(CRT_END) */ + +#else /* OBJECT_FORMAT_MACHO */ + +/* For Mach-O format executables, we assume that the system's runtime is + smart enough to handle constructors and destructors, but doesn't have + an init section (if it can't even handle constructors/destructors + you should be using INVOKE__main, not crtstuff). All we need to do + is install/deinstall the frame information for exceptions. We do this + by putting a constructor in crtbegin.o and a destructor in crtend.o. + + crtend.o also puts in the terminating zero in the frame information + segment. */ + +/* The crtstuff for other object formats use the symbol __EH_FRAME_BEGIN__ + to figure out the start of the exception frame, but here we use + getsectbynamefromheader to find this value. Either method would work, + but this method avoids creating any global symbols, which seems + cleaner. */ + +#include <mach-o/ldsyms.h> +extern const struct section * + getsectbynamefromheader (const struct mach_header *, + const char *, const char *); + +#ifdef CRT_BEGIN + +static void __reg_frame_ctor () __attribute__ ((constructor)); + +static void +__reg_frame_ctor (void) +{ + static struct object object; + const struct section *eh_frame; + + eh_frame = getsectbynamefromheader (&_mh_execute_header, + "__TEXT", "__eh_frame"); + __register_frame_info ((void *) eh_frame->addr, &object); +} + +#endif /* CRT_BEGIN */ + +#ifdef CRT_END + +static void __dereg_frame_dtor () __attribute__ ((destructor)); + +static +void +__dereg_frame_dtor (void) +{ + const struct section *eh_frame; + + eh_frame = getsectbynamefromheader (&_mh_execute_header, + "__TEXT", "__eh_frame"); + __deregister_frame_info ((void *) eh_frame->addr); +} + +/* Terminate the frame section with a final zero. */ + +/* Force cc1 to switch to .data section. */ +static void * force_to_data[0] __attribute__ ((__unused__)) = { }; + +typedef unsigned int ui32 __attribute__ ((mode (SI))); +asm (EH_FRAME_SECTION_ASM_OP); +static ui32 __FRAME_END__[] __attribute__ ((__unused__)) = { 0 }; + +#endif /* CRT_END */ + +#endif /* OBJECT_FORMAT_MACHO */ + |