gcconfig.h

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			      /* We could use _etext instead, but that  */
			      /* would include .rodata, which may       */
			      /* contain large read-only data tables    */
			      /* that we'd rather not scan.		*/
#	     endif
	     extern int _end[];
#	     define DATAEND (_end)
#	else
	     extern int etext[];
#            define DATASTART ((ptr_t)((((word) (etext)) + 0xfff) & ~0xfff))
#       endif
#	ifdef USE_I686_PREFETCH
#	  define PREFETCH(x) \
	    __asm__ __volatile__ ("	prefetchnta	%0": : "m"(*(char *)(x)))
	    /* Empirically prefetcht0 is much more effective at reducing	*/
	    /* cache miss stalls for the targetted load instructions.  But it	*/
	    /* seems to interfere enough with other cache traffic that the net	*/
	    /* result is worse than prefetchnta.				*/
#         if 0 
	    /* Using prefetches for write seems to have a slight negative	*/
	    /* impact on performance, at least for a PIII/500.			*/
#	    define PREFETCH_FOR_WRITE(x) \
	      __asm__ __volatile__ ("	prefetcht0	%0": : "m"(*(char *)(x)))
#	  endif
#	endif
#	ifdef USE_3DNOW_PREFETCH
#	  define PREFETCH(x) \
	    __asm__ __volatile__ ("	prefetch	%0": : "m"(*(char *)(x)))
#	  define PREFETCH_FOR_WRITE(x) \
	    __asm__ __volatile__ ("	prefetchw	%0": : "m"(*(char *)(x)))
#	endif
#   endif
#   ifdef CYGWIN32
#       define OS_TYPE "CYGWIN32"
          extern int _data_start__[];
          extern int _data_end__[];
          extern int _bss_start__[];
          extern int _bss_end__[];
  	/* For binutils 2.9.1, we have			*/
  	/*	DATASTART   = _data_start__		*/
  	/*	DATAEND	    = _bss_end__		*/
  	/* whereas for some earlier versions it was	*/
  	/*	DATASTART   = _bss_start__		*/
  	/*	DATAEND	    = _data_end__		*/
  	/* To get it right for both, we take the	*/
  	/* minumum/maximum of the two.			*/
#   	define MAX(x,y) ((x) > (y) ? (x) : (y))
#   	define MIN(x,y) ((x) < (y) ? (x) : (y))
#       define DATASTART ((ptr_t) MIN(_data_start__, _bss_start__))
#       define DATAEND	 ((ptr_t) MAX(_data_end__, _bss_end__))
#	undef STACK_GRAN
#       define STACK_GRAN 0x10000
#       define HEURISTIC1
#   endif
#   ifdef OS2
#	define OS_TYPE "OS2"
 	    	/* STACKBOTTOM and DATASTART are handled specially in 	*/
		/* os_dep.c. OS2 actually has the right			*/
		/* system call!						*/
#	define DATAEND	/* not needed */
#	define USE_GENERIC_PUSH_REGS
#   endif
#   ifdef MSWIN32
#	define OS_TYPE "MSWIN32"
		/* STACKBOTTOM and DATASTART are handled specially in 	*/
		/* os_dep.c.						*/
#       ifndef __WATCOMC__
#	  define MPROTECT_VDB
#	endif
#       define DATAEND  /* not needed */
#   endif
#   ifdef MSWINCE
#	define OS_TYPE "MSWINCE"
#       define DATAEND  /* not needed */
#   endif
#   ifdef DJGPP
#       define OS_TYPE "DJGPP"
#       include "stubinfo.h"
        extern int etext[];
        extern int _stklen;
        extern int __djgpp_stack_limit;
#       define DATASTART ((ptr_t)((((word) (etext)) + 0x1ff) & ~0x1ff))
/* #       define STACKBOTTOM ((ptr_t)((word) _stubinfo + _stubinfo->size \
                                                     + _stklen)) */
#       define STACKBOTTOM ((ptr_t)((word) __djgpp_stack_limit + _stklen))
		/* This may not be right.  */
#   endif
#   ifdef OPENBSD
#	define OS_TYPE "OPENBSD"
#   endif
#   ifdef FREEBSD
#	define OS_TYPE "FREEBSD"
#	ifndef GC_FREEBSD_THREADS
#	    define MPROTECT_VDB
#	endif
#	define SIG_SUSPEND SIGUSR1
#	define SIG_THR_RESTART SIGUSR2
#	define FREEBSD_STACKBOTTOM
#	ifdef __ELF__
#	    define DYNAMIC_LOADING
#	endif
/* Handle unmapped hole i386*-*-freebsd[45]* may put between etext and edata. */
	extern char etext[];
	extern char edata[];
	extern char end[];
#	define NEED_FIND_LIMIT
#	define DATASTART ((ptr_t)(etext))
#   	define MIN(x,y) ((x) < (y) ? (x) : (y))
#	define DATAEND (MIN (GC_find_limit (DATASTART, TRUE), DATASTART2))
#	define DATASTART2 ((ptr_t)(edata))
#	define DATAEND2 ((ptr_t)(end))
#   endif
#   ifdef NETBSD
#	define OS_TYPE "NETBSD"
#	ifdef __ELF__
#	    define DYNAMIC_LOADING
#	endif
#   endif
#   ifdef THREE86BSD
#	define OS_TYPE "THREE86BSD"
#   endif
#   ifdef BSDI
#	define OS_TYPE "BSDI"
#   endif
#   if defined(OPENBSD) || defined(NETBSD) \
        || defined(THREE86BSD) || defined(BSDI)
#	define HEURISTIC2
	extern char etext[];
#	define DATASTART ((ptr_t)(etext))
#   endif
#   ifdef NEXT
#	define OS_TYPE "NEXT"
#	define DATASTART ((ptr_t) get_etext())
#	define STACKBOTTOM ((ptr_t)0xc0000000)
#	define DATAEND	/* not needed */
#   endif
#   ifdef DOS4GW
#     define OS_TYPE "DOS4GW"
      extern long __nullarea;
      extern char _end;
      extern char *_STACKTOP;
      /* Depending on calling conventions Watcom C either precedes
         or does not precedes with undescore names of C-variables.
         Make sure startup code variables always have the same names.  */
      #pragma aux __nullarea "*";
      #pragma aux _end "*";
#     define STACKBOTTOM ((ptr_t) _STACKTOP)
                         /* confused? me too. */
#     define DATASTART ((ptr_t) &__nullarea)
#     define DATAEND ((ptr_t) &_end)
#   endif
#   ifdef HURD
#     define OS_TYPE "HURD"
#     define STACK_GROWS_DOWN
#     define HEURISTIC2
      extern int  __data_start[];
#     define DATASTART ( (ptr_t) (__data_start))
      extern int   _end[];
#     define DATAEND ( (ptr_t) (_end))
/* #     define MPROTECT_VDB  Not quite working yet? */
#     define DYNAMIC_LOADING
#   endif
# endif

# ifdef NS32K
#   define MACH_TYPE "NS32K"
#   define ALIGNMENT 4
    extern char **environ;
#   define DATASTART ((ptr_t)(&environ))
			      /* hideous kludge: environ is the first   */
			      /* word in crt0.o, and delimits the start */
			      /* of the data segment, no matter which   */
			      /* ld options were passed through.        */
#   define STACKBOTTOM ((ptr_t) 0xfffff000) /* for Encore */
# endif

# ifdef MIPS
#   define MACH_TYPE "MIPS"
#   ifdef LINUX
      /* This was developed for a linuxce style platform.  Probably	*/
      /* needs to be tweaked for workstation class machines.		*/
#     define OS_TYPE "LINUX"
#     define DYNAMIC_LOADING
      extern int _end[];
#     define DATAEND (_end)
      extern int __data_start[];
#     define DATASTART ((ptr_t)(__data_start))
#     define ALIGNMENT 4
#     define USE_GENERIC_PUSH_REGS
#     define LINUX_STACKBOTTOM
#   endif /* Linux */
#   ifdef EWS4800
#      define HEURISTIC2
#      if defined(_MIPS_SZPTR) && (_MIPS_SZPTR == 64)
         extern int _fdata[], _end[];
#        define DATASTART ((ptr_t)_fdata)
#        define DATAEND ((ptr_t)_end)
#        define CPP_WORDSZ _MIPS_SZPTR
#        define ALIGNMENT (_MIPS_SZPTR/8)
#      else
         extern int etext[], edata[], end[];
         extern int _DYNAMIC_LINKING[], _gp[];
#        define DATASTART ((ptr_t)((((word)etext + 0x3ffff) & ~0x3ffff) \
               + ((word)etext & 0xffff)))
#        define DATAEND (edata)
#        define DATASTART2 (_DYNAMIC_LINKING \
               ? (ptr_t)(((word)_gp + 0x8000 + 0x3ffff) & ~0x3ffff) \
               : (ptr_t)edata)
#        define DATAEND2 (end)
#        define ALIGNMENT 4
#      endif
#      define OS_TYPE "EWS4800"
#      define USE_GENERIC_PUSH_REGS 1
#   endif
#   ifdef ULTRIX
#	define HEURISTIC2
#       define DATASTART (ptr_t)0x10000000
			      /* Could probably be slightly higher since */
			      /* startup code allocates lots of stuff.   */
#	define OS_TYPE "ULTRIX"
#       define ALIGNMENT 4
#   endif
#   ifdef RISCOS
#	define HEURISTIC2
#       define DATASTART (ptr_t)0x10000000
#	define OS_TYPE "RISCOS"
#   	define ALIGNMENT 4  /* Required by hardware */
#   endif
#   ifdef IRIX5
#	define HEURISTIC2
        extern int _fdata[];
#       define DATASTART ((ptr_t)(_fdata))
#       ifdef USE_MMAP
#         define HEAP_START (ptr_t)0x30000000
#       else
#	  define HEAP_START DATASTART
#       endif
			      /* Lowest plausible heap address.		*/
			      /* In the MMAP case, we map there.	*/
			      /* In either case it is used to identify	*/
			      /* heap sections so they're not 		*/
			      /* considered as roots.			*/
#	define OS_TYPE "IRIX5"
#       define MPROTECT_VDB
#       ifdef _MIPS_SZPTR
#	  define CPP_WORDSZ _MIPS_SZPTR
#	  define ALIGNMENT (_MIPS_SZPTR/8)
#	  if CPP_WORDSZ != 64
#	    define ALIGN_DOUBLE
#	  endif
#	else
#         define ALIGNMENT 4
#	  define ALIGN_DOUBLE
#	endif
#	define DYNAMIC_LOADING
#   endif
#   ifdef MSWINCE
#       define OS_TYPE "MSWINCE"
#       define ALIGNMENT 4
#       define DATAEND /* not needed */
#   endif
#   if defined(NETBSD)
#     define OS_TYPE "NETBSD"
#     define ALIGNMENT 4
#     define HEURISTIC2
#     define USE_GENERIC_PUSH_REGS
      extern int _fdata[];
#     define DATASTART ((ptr_t)(_fdata))
      extern int _end[];
#     define DATAEND ((ptr_t)(_end))
#     define DYNAMIC_LOADING
#  endif
# endif

# ifdef RS6000
#   define MACH_TYPE "RS6000"
#   ifdef __64BIT__
#     define ALIGNMENT 8
#     define CPP_WORDSZ 64
#   else
#     define ALIGNMENT 4
#     define CPP_WORDSZ 32
#   endif
    extern int _data[], _end[];
#   define DATASTART ((ptr_t)((ulong)_data))
#   define DATAEND ((ptr_t)((ulong)_end))
    extern int errno;
#   define STACKBOTTOM ((ptr_t)((ulong)&errno))
#   define USE_GENERIC_PUSH_REGS
#   define DYNAMIC_LOADING
	/* For really old versions of AIX, this may have to be removed. */
# endif

# ifdef HP_PA
#   define MACH_TYPE "HP_PA"
#   ifdef __LP64__
#     define CPP_WORDSZ 64
#     define ALIGNMENT 8
#   else
#     define CPP_WORDSZ 32
#     define ALIGNMENT 4
#     define ALIGN_DOUBLE
#   endif
#   if !defined(GC_HPUX_THREADS) && !defined(GC_LINUX_THREADS)
#     ifndef LINUX /* For now. */
#       define MPROTECT_VDB
#     endif
#   else
#     define GENERIC_COMPARE_AND_SWAP
	/* No compare-and-swap instruction.  Use pthread mutexes 	*/
	/* when we absolutely have to.					*/
#     ifdef PARALLEL_MARK
#	define USE_MARK_BYTES
		/* Minimize compare-and-swap usage.		*/
#     endif
#   endif
#   define STACK_GROWS_UP
#   ifdef HPUX
#     define OS_TYPE "HPUX"
      extern int __data_start[];
#     define DATASTART ((ptr_t)(__data_start))
#     if 0
	/* The following appears to work for 7xx systems running HP/UX	*/
	/* 9.xx Furthermore, it might result in much faster		*/
	/* collections than HEURISTIC2, which may involve scanning	*/
	/* segments that directly precede the stack.  It is not the	*/
	/* default, since it may not work on older machine/OS		*/
	/* combinations. (Thanks to Raymond X.T. Nijssen for uncovering	*/
	/* this.)							*/
#       define STACKBOTTOM ((ptr_t) 0x7b033000)  /* from /etc/conf/h/param.h */
#     else
	/* Gustavo Rodriguez-Rivera suggested changing HEURISTIC2	*/
	/* to this.  Note that the GC must be initialized before the	*/
    	/* first putenv call.						*/
	extern char ** environ;
#       define STACKBOTTOM ((ptr_t)environ)
#     endif
#     define DYNAMIC_LOADING
#     include <unistd.h>
#     define GETPAGESIZE() sysconf(_SC_PAGE_SIZE)
#     ifndef __GNUC__
#       define PREFETCH(x)  { \
                              register long addr = (long)(x); \
                              (void) _asm ("LDW", 0, 0, addr, 0); \
                            }
#     endif
#   endif /* HPUX */
#   ifdef LINUX
#     define OS_TYPE "LINUX"
#     define LINUX_STACKBOTTOM
#     define DYNAMIC_LOADING
#     define LINUX_DATA_START
      extern int _end[];
#     define DATAEND (_end)
#   endif /* LINUX */
# endif /* HP_PA */

# ifdef ALPHA
#   define MACH_TYPE "ALPHA"
#   define ALIGNMENT 8
#   ifdef NETBSD
#	define OS_TYPE "NETBSD"
#	define HEURISTIC2
#	define DATASTART GC_data_start
#	define ELFCLASS32 32
#	define ELFCLASS64 64
#	define ELF_CLASS ELFCLASS64
#   	define CPP_WORDSZ 64
#       define DYNAMIC_LOADING
#   endif
#   ifdef OPENBSD
#	define OS_TYPE "OPENBSD"
#	define HEURISTIC2
#   	define CPP_WORDSZ 64
#   	ifdef __ELF__	/* since OpenBSD/Alpha 2.9 */
#	   define DATASTART GC_data_start
#   	   define ELFCLASS32 32
#   	   define ELFCLASS64 64
#   	   define ELF_CLASS ELFCLASS64
#       else		/* ECOFF, until OpenBSD/Alpha 2.7 */
#   	   define DATASTART ((ptr_t) 0x140000000)
#   	endif
#   endif
#   ifdef FREEBSD
#	define OS_TYPE "FREEBSD"
/* MPROTECT_VDB is not yet supported at all on FreeBSD/alpha. */
#	define SIG_SUSPEND SIGUSR1
#	define SIG_THR_RESTART SIGUSR2
#	define FREEBSD_STACKBOTTOM
#	ifdef __ELF__
#	    define DYNAMIC_LOADING
#	endif
/* Handle unmapped hole alpha*-*-freebsd[45]* puts between etext and edata. */
	extern char etext[];
	extern char edata[];
	extern char end[];
#	define NEED_FIND_LIMIT
#	define DATASTART ((ptr_t)(etext))
#	define DATAEND (GC_find_limit (DATASTART, TRUE))
#	define DATASTART2 ((ptr_t)(edata))
#	define DATAEND2 ((ptr_t)(end))
#	define CPP_WORDSZ 64
#   endif
#   ifdef OSF1
#	define OS_TYPE "OSF1"
#   	define DATASTART ((ptr_t) 0x140000000)
	extern int _end[];
#   	define DATAEND ((ptr_t) _end)
 	extern char ** environ;
	/* round up from the value of environ to the nearest page boundary */
	/* Probably breaks if putenv is called before collector 	   */
	/* initialization.						   */
#	define STACKBOTTOM ((ptr_t)(((word)(environ) | (getpagesize()-1))+1))
/* #   	define HEURISTIC2 */
	/* Normally HEURISTIC2 is too conervative, since		*/
	/* the text segment immediately follows the stack.		*/
	/* Hence we give an upper pound.				*/
	/* This is currently unused, since we disabled HEURISTIC2	*/
    	extern int __start[];
#   	define HEURISTIC2_LIMIT ((ptr_t)((word)(__start) & ~(getpagesize()-1)))
#   	define CPP_WORDSZ 64
#   	define MPROTECT_VDB
#   	define DYNAMIC_LOADING
#   endif
#   ifdef LINUX
#       define OS_TYPE "LINUX"
#       define CPP_WORDSZ 64
#       define STACKBOTTOM ((ptr_t) 0x120000000)
#       ifdef __ELF__
#	  define SEARCH_FOR_DATA_START
#	  define DATASTART GC_data_start
#         define DYNAMIC_LOADING
#       else
#           define DATASTART ((ptr_t) 0x140000000)
#       endif
	extern int _end[];
#	define DATAEND (_end)
#	define MPROTECT_VDB
		/* Has only been superficially tested.  May not	*/
		/* work on all versions.			*/
#   endif
# endif

# ifdef IA64
#   define MACH_TYPE "IA64"
#   define USE_GENERIC_PUSH_REGS
	/* We need to get preserved registers in addition to register   */
	/* windows.   That's easiest to do with setjmp.			*/
#   ifdef PARALLEL_MARK
#	define USE_MARK_BYTES
	    /* Compare-and-exchange is too expensive to use for 	*/
	    /* setting mark bits.					*/
#   endif
#   ifdef HPUX
#	ifdef _ILP32
#	  define CPP_WORDSZ 32
#         define ALIGN_DOUBLE
	    /* Requires 8 byte alignment for malloc */
#   	  define ALIGNMENT 4
#       else
#	  ifndef _LP64
		---> unknown ABI
#         endif
#	  define CPP_WORDSZ 64
#   	  define ALIGN_DOUBLE
	    /* Requires 16 byte alignment for malloc */
#         define ALIGNMENT 8
#       endif
#       define OS_TYPE "HPUX"	
        extern int __data_start[];
#       define DATASTART ((ptr_t)(__data_start))
        /* Gustavo Rodriguez-Rivera suggested changing HEURISTIC2	*/
        /* to this.  Note that the GC must be initialized before the	*/
    	/* first putenv call.						*/
	extern char ** environ;
#       define STACKBOTTOM ((ptr_t)environ)
#       define DYNAMIC_LOADING
#       include <unistd.h>
#       define GETPAGESIZE() sysconf(_SC_PAGE_SIZE)
 	/* The following was empirically determined, and is probably	*/
	/* not very robust.						*/