1 /*
2  * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3  * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
4  * Copyright (c) 1996 by Silicon Graphics.  All rights reserved.
5  * Copyright (c) 2000-2004 Hewlett-Packard Development Company, L.P.
6  *
7  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
8  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
9  *
10  * Permission is hereby granted to use or copy this program
11  * for any purpose,  provided the above notices are retained on all copies.
12  * Permission to modify the code and to distribute modified code is granted,
13  * provided the above notices are retained, and a notice that the code was
14  * modified is included with the above copyright notice.
15  */
16 
17 /*
18  * This header is private to the gc.  It is almost always included from
19  * gc_priv.h.  However it is possible to include it by itself if just the
20  * configuration macros are needed.  In that
21  * case, a few declarations relying on types declared in gc_priv.h will be
22  * omitted.
23  */
24 
25 #ifndef GCCONFIG_H
26 
27 # define GCCONFIG_H
28 
29 # ifndef GC_PRIVATE_H
30     /* Fake ptr_t declaration, just to avoid compilation errors.	*/
31     /* This avoids many instances if "ifndef GC_PRIVATE_H" below.	*/
32     typedef struct GC_undefined_struct * ptr_t;
33 # endif
34 
35 /* Machine dependent parameters.  Some tuning parameters can be found	*/
36 /* near the top of gc_private.h.					*/
37 
38 /* Machine specific parts contributed by various people.  See README file. */
39 
40 /* First a unified test for Linux: */
41 # if defined(linux) || defined(__linux__)
42 #  ifndef LINUX
43 #    define LINUX
44 #  endif
45 # endif
46 
47 /* And one for NetBSD: */
48 # if defined(__NetBSD__)
49 #    define NETBSD
50 # endif
51 
52 /* And one for OpenBSD: */
53 # if defined(__OpenBSD__)
54 #    define OPENBSD
55 # endif
56 
57 /* And one for FreeBSD: */
58 # if ( defined(__FreeBSD__) || defined(__FreeBSD_kernel__) ) && !defined(FREEBSD)
59 #    define FREEBSD
60 # endif
61 
62 /* Determine the machine type: */
63 # if defined(__arm__) || defined(__thumb__)
64 #    define ARM32
65 #    if !defined(LINUX) && !defined(NETBSD)
66 #      define NOSYS
67 #      define mach_type_known
68 #    endif
69 # endif
70 # if defined(sun) && defined(mc68000)
71 #    define M68K
72 #    define SUNOS4
73 #    define mach_type_known
74 # endif
75 # if defined(hp9000s300)
76 #    define M68K
77 #    define HP
78 #    define mach_type_known
79 # endif
80 # if defined(OPENBSD) && defined(m68k)
81 #    define M68K
82 #    define mach_type_known
83 # endif
84 # if defined(OPENBSD) && defined(__sparc__)
85 #    define SPARC
86 #    define mach_type_known
87 # endif
88 # if defined(NETBSD) && (defined(m68k) || defined(__m68k__))
89 #    define M68K
90 #    define mach_type_known
91 # endif
92 # if defined(NETBSD) && defined(__powerpc__)
93 #    define POWERPC
94 #    define mach_type_known
95 # endif
96 # if defined(NETBSD) && (defined(__arm32__) || defined(__arm__))
97 #    define ARM32
98 #    define mach_type_known
99 # endif
100 # if defined(NETBSD) && defined(__sh__)
101 #    define SH
102 #    define mach_type_known
103 # endif
104 # if defined(vax)
105 #    define VAX
106 #    ifdef ultrix
107 #	define ULTRIX
108 #    else
109 #	define BSD
110 #    endif
111 #    define mach_type_known
112 # endif
113 # if defined(__NetBSD__) && defined(__vax__)
114 #    define VAX
115 #    define mach_type_known
116 # endif
117 # if defined(mips) || defined(__mips) || defined(_mips)
118 #    define MIPS
119 #    if defined(nec_ews) || defined(_nec_ews)
120 #      define EWS4800
121 #    endif
122 #    if !defined(LINUX) && !defined(EWS4800) && !defined(NETBSD)
123 #      if defined(ultrix) || defined(__ultrix)
124 #	 define ULTRIX
125 #      else
126 #	 if defined(_SYSTYPE_SVR4) || defined(SYSTYPE_SVR4) \
127 	    || defined(__SYSTYPE_SVR4__)
128 #	   define IRIX5   /* or IRIX 6.X */
129 #	 else
130 #	   define RISCOS  /* or IRIX 4.X */
131 #	 endif
132 #      endif
133 #    endif /* !LINUX */
134 #    if defined(__NetBSD__) && defined(__MIPSEL__)
135 #      undef ULTRIX
136 #    endif
137 #    define mach_type_known
138 # endif
139 # if defined(DGUX) && (defined(i386) || defined(__i386__))
140 #    define I386
141 #    ifndef _USING_DGUX
142 #    define _USING_DGUX
143 #    endif
144 #    define mach_type_known
145 # endif
146 # if defined(sequent) && (defined(i386) || defined(__i386__))
147 #    define I386
148 #    define SEQUENT
149 #    define mach_type_known
150 # endif
151 # if defined(sun) && (defined(i386) || defined(__i386__))
152 #    define I386
153 #    define SUNOS5
154 #    define mach_type_known
155 # endif
156 # if defined(sun) && defined(__amd64)
157 #    define X86_64
158 #    define SUNOS5
159 #    define mach_type_known
160 # endif
161 # if (defined(__OS2__) || defined(__EMX__)) && defined(__32BIT__)
162 #    define I386
163 #    define OS2
164 #    define mach_type_known
165 # endif
166 # if defined(ibm032)
167 #   define RT
168 #   define mach_type_known
169 # endif
170 # if defined(sun) && (defined(sparc) || defined(__sparc))
171 #   define SPARC
172     /* Test for SunOS 5.x */
173 #     include <errno.h>
174 #     ifdef ECHRNG
175 #       define SUNOS5
176 #     else
177 #	define SUNOS4
178 #     endif
179 #   define mach_type_known
180 # endif
181 # if defined(sparc) && defined(unix) && !defined(sun) && !defined(linux) \
182      && !defined(__OpenBSD__) && !defined(__NetBSD__) && !defined(__FreeBSD__)
183 #   define SPARC
184 #   define DRSNX
185 #   define mach_type_known
186 # endif
187 # if defined(_IBMR2)
188 #   define RS6000
189 #   define mach_type_known
190 # endif
191 # if defined(__NetBSD__) && defined(__sparc__)
192 #   define SPARC
193 #   define mach_type_known
194 # endif
195 # if defined(_M_XENIX) && defined(_M_SYSV) && defined(_M_I386)
196 	/* The above test may need refinement	*/
197 #   define I386
198 #   if defined(_SCO_ELF)
199 #     define SCO_ELF
200 #   else
201 #     define SCO
202 #   endif
203 #   define mach_type_known
204 # endif
205 # if defined(_AUX_SOURCE)
206 #   define M68K
207 #   define SYSV
208 #   define mach_type_known
209 # endif
210 # if defined(_PA_RISC1_0) || defined(_PA_RISC1_1) || defined(_PA_RISC2_0) \
211      || defined(hppa) || defined(__hppa__)
212 #   define HP_PA
213 #   if !defined(LINUX) && !defined(HPUX)
214 #     define HPUX
215 #   endif
216 #   define mach_type_known
217 # endif
218 # if defined(__ia64) && defined(_HPUX_SOURCE)
219 #   define IA64
220 #   ifndef HPUX
221 #     define HPUX
222 #   endif
223 #   define mach_type_known
224 # endif
225 # if defined(__BEOS__) && defined(_X86_)
226 #    define I386
227 #    define BEOS
228 #    define mach_type_known
229 # endif
230 # if defined(LINUX) && (defined(i386) || defined(__i386__))
231 #    define I386
232 #    define mach_type_known
233 # endif
234 # if defined(LINUX) && defined(__x86_64__)
235 #    define X86_64
236 #    define mach_type_known
237 # endif
238 # if defined(LINUX) && (defined(__ia64__) || defined(__ia64))
239 #    define IA64
240 #    define mach_type_known
241 # endif
242 # if defined(LINUX) && defined(__arm__)
243 #    define ARM32
244 #    define mach_type_known
245 # endif
246 # if defined(LINUX) && defined(__cris__)
247 #    ifndef CRIS
248 #	define CRIS
249 #    endif
250 #    define mach_type_known
251 # endif
252 # if defined(LINUX) && (defined(powerpc) || defined(__powerpc__) || \
253 		        defined(powerpc64) || defined(__powerpc64__))
254 #    define POWERPC
255 #    define mach_type_known
256 # endif
257 # if defined(FREEBSD) && (defined(powerpc) || defined(__powerpc__))
258 #    define POWERPC
259 #    define mach_type_known
260 # endif
261 # if defined(LINUX) && defined(__mc68000__)
262 #    define M68K
263 #    define mach_type_known
264 # endif
265 # if defined(LINUX) && (defined(sparc) || defined(__sparc__))
266 #    define SPARC
267 #    define mach_type_known
268 # endif
269 # if defined(LINUX) && defined(__arm__)
270 #    define ARM32
271 #    define mach_type_known
272 # endif
273 # if defined(LINUX) && defined(__sh__)
274 #    define SH
275 #    define mach_type_known
276 # endif
277 # if defined(LINUX) && defined(__m32r__)
278 #    define M32R
279 #    define mach_type_known
280 # endif
281 # if defined(__alpha) || defined(__alpha__)
282 #   define ALPHA
283 #   if !defined(LINUX) && !defined(NETBSD) && !defined(OPENBSD) && !defined(FREEBSD)
284 #     define OSF1	/* a.k.a Digital Unix */
285 #   endif
286 #   define mach_type_known
287 # endif
288 # if defined(_AMIGA) && !defined(AMIGA)
289 #   define AMIGA
290 # endif
291 # ifdef AMIGA
292 #   define M68K
293 #   define mach_type_known
294 # endif
295 # if defined(THINK_C) || defined(__MWERKS__) && !defined(__powerc)
296 #   define M68K
297 #   define MACOS
298 #   define mach_type_known
299 # endif
300 # if defined(__MWERKS__) && defined(__powerc) && !defined(__MACH__)
301 #   define POWERPC
302 #   define MACOS
303 #   define mach_type_known
304 # endif
305 # if defined(macosx) || (defined(__APPLE__) && defined(__MACH__))
306 #   define DARWIN
307 #   if defined(__ppc__)  || defined(__ppc64__)
308 #    define POWERPC
309 #    define mach_type_known
310 #   elif defined(__x86_64__)
311 #    define X86_64
312 #    define mach_type_known
313 #   elif defined(__i386__)
314 #    define I386
315 #    define mach_type_known
316 #   endif
317 # endif
318 # if defined(NeXT) && defined(mc68000)
319 #   define M68K
320 #   define NEXT
321 #   define mach_type_known
322 # endif
323 # if defined(NeXT) && (defined(i386) || defined(__i386__))
324 #   define I386
325 #   define NEXT
326 #   define mach_type_known
327 # endif
328 # if defined(__OpenBSD__) && (defined(i386) || defined(__i386__))
329 #   define I386
330 #   define OPENBSD
331 #   define mach_type_known
332 # endif
333 # if defined(FREEBSD) && (defined(i386) || defined(__i386__))
334 #   define I386
335 #   define mach_type_known
336 # endif
337 # if defined(FREEBSD) && defined(__x86_64__)
338 #   define X86_64
339 #   define mach_type_known
340 # endif
341 # if defined(__NetBSD__) && (defined(i386) || defined(__i386__))
342 #   define I386
343 #   define mach_type_known
344 # endif
345 # if defined(__NetBSD__) && defined(__x86_64__)
346 #    define X86_64
347 #    define mach_type_known
348 # endif
349 # if defined(FREEBSD) && defined(__sparc__)
350 #    define SPARC
351 #    define mach_type_known
352 #endif
353 # if defined(bsdi) && (defined(i386) || defined(__i386__))
354 #    define I386
355 #    define BSDI
356 #    define mach_type_known
357 # endif
358 # if !defined(mach_type_known) && defined(__386BSD__)
359 #   define I386
360 #   define THREE86BSD
361 #   define mach_type_known
362 # endif
363 # if defined(_CX_UX) && defined(_M88K)
364 #   define M88K
365 #   define CX_UX
366 #   define mach_type_known
367 # endif
368 # if defined(DGUX) && defined(m88k)
369 #   define M88K
370     /* DGUX defined */
371 #   define mach_type_known
372 # endif
373 # if defined(_WIN32_WCE)
374     /* SH3, SH4, MIPS already defined for corresponding architectures */
375 #   if defined(SH3) || defined(SH4)
376 #     define SH
377 #   endif
378 #   if defined(x86)
379 #     define I386
380 #   endif
381 #   if defined(ARM)
382 #     define ARM32
383 #   endif
384 #   define MSWINCE
385 #   define mach_type_known
386 # else
387 #   if (defined(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \
388         || defined(_WIN32) && !defined(__CYGWIN32__) && !defined(__CYGWIN__)
389 #     define I386
390 #     define MSWIN32	/* or Win32s */
391 #     define mach_type_known
392 #   endif
393 #   if defined(_MSC_VER) && defined(_M_IA64)
394 #     define IA64
395 #     define MSWIN32	/* Really win64, but we don't treat 64-bit 	*/
396 			/* variants as a differnt platform.		*/
397 #   endif
398 # endif
399 # if defined(__DJGPP__)
400 #   define I386
401 #   ifndef DJGPP
402 #     define DJGPP  /* MSDOS running the DJGPP port of GCC */
403 #   endif
404 #   define mach_type_known
405 # endif
406 # if defined(__CYGWIN32__) || defined(__CYGWIN__)
407 #   define I386
408 #   define CYGWIN32
409 #   define mach_type_known
410 # endif
411 # if defined(__MINGW32__)
412 #   define I386
413 #   define MSWIN32
414 #   define mach_type_known
415 # endif
416 # if defined(__BORLANDC__)
417 #   define I386
418 #   define MSWIN32
419 #   define mach_type_known
420 # endif
421 # if defined(_UTS) && !defined(mach_type_known)
422 #   define S370
423 #   define UTS4
424 #   define mach_type_known
425 # endif
426 # if defined(__pj__)
427 #   define PJ
428 #   define mach_type_known
429 # endif
430 # if defined(__embedded__) && defined(PPC)
431 #   define POWERPC
432 #   define NOSYS
433 #   define mach_type_known
434 # endif
435 /* Ivan Demakov */
436 # if defined(__WATCOMC__) && defined(__386__)
437 #   define I386
438 #   if !defined(OS2) && !defined(MSWIN32) && !defined(DOS4GW)
439 #     if defined(__OS2__)
440 #       define OS2
441 #     else
442 #       if defined(__WINDOWS_386__) || defined(__NT__)
443 #         define MSWIN32
444 #       else
445 #         define DOS4GW
446 #       endif
447 #     endif
448 #   endif
449 #   define mach_type_known
450 # endif
451 # if defined(__s390__) && defined(LINUX)
452 #    define S390
453 #    define mach_type_known
454 # endif
455 # if defined(__GNU__)
456 #   if defined(__i386__)
457 /* The Debian Hurd running on generic PC */
458 #     define  HURD
459 #     define  I386
460 #     define  mach_type_known
461 #    endif
462 # endif
463 
464 /* Feel free to add more clauses here */
465 
466 /* Or manually define the machine type here.  A machine type is 	*/
467 /* characterized by the architecture.  Some				*/
468 /* machine types are further subdivided by OS.				*/
469 /* the macros ULTRIX, RISCOS, and BSD to distinguish.			*/
470 /* Note that SGI IRIX is treated identically to RISCOS.			*/
471 /* SYSV on an M68K actually means A/UX.					*/
472 /* The distinction in these cases is usually the stack starting address */
473 # ifndef mach_type_known
474 	--> unknown machine type
475 # endif
476 		    /* Mapping is: M68K       ==> Motorola 680X0	*/
477 		    /*		   (SUNOS4,HP,NEXT, and SYSV (A/UX),	*/
478 		    /*		   MACOS and AMIGA variants)		*/
479 		    /*             I386       ==> Intel 386	 	*/
480 		    /*		    (SEQUENT, OS2, SCO, LINUX, NETBSD,	*/
481 		    /*		     FREEBSD, THREE86BSD, MSWIN32,	*/
482 		    /* 		     BSDI,SUNOS5, NEXT, other variants)	*/
483                     /*             NS32K      ==> Encore Multimax 	*/
484                     /*             MIPS       ==> R2000 or R3000	*/
485                     /*			(RISCOS, ULTRIX variants)	*/
486                     /*		   VAX	      ==> DEC VAX		*/
487                     /*			(BSD, ULTRIX variants)		*/
488                     /*		   RS6000     ==> IBM RS/6000 AIX3.X	*/
489                     /*		   RT	      ==> IBM PC/RT		*/
490                     /*		   HP_PA      ==> HP9000/700 & /800	*/
491                     /*				  HP/UX, LINUX		*/
492 		    /*		   SPARC      ==> SPARC	v7/v8/v9	*/
493 		    /*			(SUNOS4, SUNOS5, LINUX,		*/
494 		    /*			 DRSNX variants)		*/
495 		    /* 		   ALPHA      ==> DEC Alpha 		*/
496 		    /*			(OSF1 and LINUX variants)	*/
497 		    /* 		   M88K       ==> Motorola 88XX0        */
498 		    /* 		        (CX_UX and DGUX)		*/
499 		    /* 		   S370	      ==> 370-like machine	*/
500 		    /* 			running Amdahl UTS4		*/
501                     /*             S390       ==> 390-like machine      */
502 		    /*                  running LINUX                   */
503 		    /* 		   ARM32      ==> Intel StrongARM	*/
504 		    /* 		   IA64	      ==> Intel IPF		*/
505 		    /*				  (e.g. Itanium)	*/
506 		    /*			(LINUX and HPUX)	        */
507 		    /*		   SH	      ==> Hitachi SuperH	*/
508 		    /* 			(LINUX & MSWINCE)		*/
509 		    /* 		   X86_64     ==> AMD x86-64		*/
510 		    /*		   POWERPC    ==> IBM/Apple PowerPC	*/
511 		    /*			(MACOS(<=9),DARWIN(incl.MACOSX),*/
512 		    /*			 LINUX, NETBSD, NOSYS variants)	*/
513 		    /*			Handles 32 and 64-bit variants.	*/
514 		    /* 			AIX should be handled here, but	*/
515 		    /*			that's called an RS6000.	*/
516 		    /*		   CRIS       ==> Axis Etrax		*/
517 		    /*		   M32R	      ==> Renesas M32R		*/
518 
519 
520 /*
521  * For each architecture and OS, the following need to be defined:
522  *
523  * CPP_WORDSZ is a simple integer constant representing the word size.
524  * in bits.  We assume byte addressibility, where a byte has 8 bits.
525  * We also assume CPP_WORDSZ is either 32 or 64.
526  * (We care about the length of pointers, not hardware
527  * bus widths.  Thus a 64 bit processor with a C compiler that uses
528  * 32 bit pointers should use CPP_WORDSZ of 32, not 64. Default is 32.)
529  *
530  * MACH_TYPE is a string representation of the machine type.
531  * OS_TYPE is analogous for the OS.
532  *
533  * ALIGNMENT is the largest N, such that
534  * all pointer are guaranteed to be aligned on N byte boundaries.
535  * defining it to be 1 will always work, but perform poorly.
536  *
537  * DATASTART is the beginning of the data segment.
538  * On some platforms SEARCH_FOR_DATA_START is defined.
539  * SEARCH_FOR_DATASTART will cause GC_data_start to
540  * be set to an address determined by accessing data backwards from _end
541  * until an unmapped page is found.  DATASTART will be defined to be
542  * GC_data_start.
543  * On UNIX-like systems, the collector will scan the area between DATASTART
544  * and DATAEND for root pointers.
545  *
546  * DATAEND, if not `end' where `end' is defined as ``extern int end[];''.
547  * RTH suggests gaining access to linker script synth'd values with
548  * this idiom instead of `&end' where `end' is defined as ``extern int end;'' .
549  * Otherwise, ``GCC will assume these are in .sdata/.sbss'' and it will, e.g.,
550  * cause failures on alpha*-*-* with ``-msmall-data or -fpic'' or mips-*-*
551  * without any special options.
552  *
553  * ALIGN_DOUBLE of GC_malloc should return blocks aligned to twice
554  * the pointer size.
555  *
556  * STACKBOTTOM is the cool end of the stack, which is usually the
557  * highest address in the stack.
558  * Under PCR or OS/2, we have other ways of finding thread stacks.
559  * For each machine, the following should:
560  * 1) define STACK_GROWS_UP if the stack grows toward higher addresses, and
561  * 2) define exactly one of
562  *	STACKBOTTOM (should be defined to be an expression)
563  *	LINUX_STACKBOTTOM
564  *	HEURISTIC1
565  *	HEURISTIC2
566  * If STACKBOTTOM is defined, then it's value will be used directly as the
567  * stack base.  If LINUX_STACKBOTTOM is defined, then it will be determined
568  * with a method appropriate for most Linux systems.  Currently we look
569  * first for __libc_stack_end, and if that fails read it from /proc.
570  * If either of the last two macros are defined, then STACKBOTTOM is computed
571  * during collector startup using one of the following two heuristics:
572  * HEURISTIC1:  Take an address inside GC_init's frame, and round it up to
573  *		the next multiple of STACK_GRAN.
574  * HEURISTIC2:  Take an address inside GC_init's frame, increment it repeatedly
575  *		in small steps (decrement if STACK_GROWS_UP), and read the value
576  *		at each location.  Remember the value when the first
577  *		Segmentation violation or Bus error is signalled.  Round that
578  *		to the nearest plausible page boundary, and use that instead
579  *		of STACKBOTTOM.
580  *
581  * Gustavo Rodriguez-Rivera points out that on most (all?) Unix machines,
582  * the value of environ is a pointer that can serve as STACKBOTTOM.
583  * I expect that HEURISTIC2 can be replaced by this approach, which
584  * interferes far less with debugging.  However it has the disadvantage
585  * that it's confused by a putenv call before the collector is initialized.
586  * This could be dealt with by intercepting putenv ...
587  *
588  * If no expression for STACKBOTTOM can be found, and neither of the above
589  * heuristics are usable, the collector can still be used with all of the above
590  * undefined, provided one of the following is done:
591  * 1) GC_mark_roots can be changed to somehow mark from the correct stack(s)
592  *    without reference to STACKBOTTOM.  This is appropriate for use in
593  *    conjunction with thread packages, since there will be multiple stacks.
594  *    (Allocating thread stacks in the heap, and treating them as ordinary
595  *    heap data objects is also possible as a last resort.  However, this is
596  *    likely to introduce significant amounts of excess storage retention
597  *    unless the dead parts of the thread stacks are periodically cleared.)
598  * 2) Client code may set GC_stackbottom before calling any GC_ routines.
599  *    If the author of the client code controls the main program, this is
600  *    easily accomplished by introducing a new main program, setting
601  *    GC_stackbottom to the address of a local variable, and then calling
602  *    the original main program.  The new main program would read something
603  *    like:
604  *
605  *		# include "gc_private.h"
606  *
607  *		main(argc, argv, envp)
608  *		int argc;
609  *		char **argv, **envp;
610  *		{
611  *		    int dummy;
612  *
613  *		    GC_stackbottom = (ptr_t)(&dummy);
614  *		    return(real_main(argc, argv, envp));
615  *		}
616  *
617  *
618  * Each architecture may also define the style of virtual dirty bit
619  * implementation to be used:
620  *   MPROTECT_VDB: Write protect the heap and catch faults.
621  *   PROC_VDB: Use the SVR4 /proc primitives to read dirty bits.
622  *
623  * An architecture may define DYNAMIC_LOADING if dynamic_load.c
624  * defined GC_register_dynamic_libraries() for the architecture.
625  *
626  * An architecture may define PREFETCH(x) to preload the cache with *x.
627  * This defaults to a no-op.
628  *
629  * PREFETCH_FOR_WRITE(x) is used if *x is about to be written.
630  *
631  * An architecture may also define CLEAR_DOUBLE(x) to be a fast way to
632  * clear the two words at GC_malloc-aligned address x.  By default,
633  * word stores of 0 are used instead.
634  *
635  * HEAP_START may be defined as the initial address hint for mmap-based
636  * allocation.
637  */
638 
639 /* If we are using a recent version of gcc, we can use __builtin_unwind_init()
640  * to push the relevant registers onto the stack.  This generally makes
641  * USE_GENERIC_PUSH_REGS the preferred approach for marking from registers.
642  */
643 # if defined(__GNUC__) && ((__GNUC__ >= 3) || \
644 			   (__GNUC__ == 2 && __GNUC_MINOR__ >= 8)) \
645 		       && !defined(__INTEL_COMPILER) \
646  		       && !defined(__PATHCC__)
647 #   define HAVE_BUILTIN_UNWIND_INIT
648 # endif
649 
650 # define STACK_GRAN 0x1000000
651 # ifdef M68K
652 #   define MACH_TYPE "M68K"
653 #   define ALIGNMENT 2
654 #   ifdef OPENBSD
655 #	define OS_TYPE "OPENBSD"
656 #	define HEURISTIC2
657 #	ifdef __ELF__
658 #	  define DATASTART GC_data_start
659 #	  define DYNAMIC_LOADING
660 #	else
661 	  extern char etext[];
662 #	  define DATASTART ((ptr_t)(etext))
663 #       endif
664 #       define USE_GENERIC_PUSH_REGS
665 #   endif
666 #   ifdef NETBSD
667 #	define OS_TYPE "NETBSD"
668 #	define HEURISTIC2
669 #	ifdef __ELF__
670 #	  define DATASTART GC_data_start
671 #	  define DYNAMIC_LOADING
672 #	else
673 	  extern char etext[];
674 #	  define DATASTART ((ptr_t)(etext))
675 #       endif
676 #	define USE_GENERIC_PUSH_REGS
677 #   endif
678 #   ifdef LINUX
679 #       define OS_TYPE "LINUX"
680 #       define LINUX_STACKBOTTOM
681 #       define USE_GENERIC_PUSH_REGS
682 		/* We never got around to the assembly version. */
683 #       define MPROTECT_VDB
684 #       ifdef __ELF__
685 #            define DYNAMIC_LOADING
686 #	     include <features.h>
687 #	     if defined(__GLIBC__)&& __GLIBC__>=2
688 #              define SEARCH_FOR_DATA_START
689 #	     else /* !GLIBC2 */
690                extern char **__environ;
691 #              define DATASTART ((ptr_t)(&__environ))
692                              /* hideous kludge: __environ is the first */
693                              /* word in crt0.o, and delimits the start */
694                              /* of the data segment, no matter which   */
695                              /* ld options were passed through.        */
696                              /* We could use _etext instead, but that  */
697                              /* would include .rodata, which may       */
698                              /* contain large read-only data tables    */
699                              /* that we'd rather not scan.             */
700 #	     endif /* !GLIBC2 */
701              extern int _end[];
702 #            define DATAEND (_end)
703 #       else
704              extern int etext[];
705 #            define DATASTART ((ptr_t)((((word) (etext)) + 0xfff) & ~0xfff))
706 #       endif
707 #   endif
708 #   ifdef SUNOS4
709 #	define OS_TYPE "SUNOS4"
710 	extern char etext[];
711 #	define DATASTART ((ptr_t)((((word) (etext)) + 0x1ffff) & ~0x1ffff))
712 #	define HEURISTIC1	/* differs	*/
713 #	define DYNAMIC_LOADING
714 #   endif
715 #   ifdef HP
716 #	define OS_TYPE "HP"
717 	extern char etext[];
718 #       define DATASTART ((ptr_t)((((word) (etext)) + 0xfff) & ~0xfff))
719 #       define STACKBOTTOM ((ptr_t) 0xffeffffc)
720 			      /* empirically determined.  seems to work. */
721 #  	include <unistd.h>
722 #	define GETPAGESIZE() sysconf(_SC_PAGE_SIZE)
723 #   endif
724 #   ifdef SYSV
725 #	define OS_TYPE "SYSV"
726 	extern etext[];
727 #   	define DATASTART ((ptr_t)((((word) (etext)) + 0x3fffff) \
728 				   & ~0x3fffff) \
729 				  +((word)etext & 0x1fff))
730 	/* This only works for shared-text binaries with magic number 0413.
731 	   The other sorts of SysV binaries put the data at the end of the text,
732 	   in which case the default of etext would work.  Unfortunately,
733 	   handling both would require having the magic-number available.
734 	   	   		-- Parag
735 	   */
736 #	define STACKBOTTOM ((ptr_t)0xFFFFFFFE)
737 			/* The stack starts at the top of memory, but   */
738 			/* 0x0 cannot be used as setjump_test complains */
739 			/* that the stack direction is incorrect.  Two  */
740 			/* bytes down from 0x0 should be safe enough.   */
741 			/* 		--Parag				*/
742 #   	include <sys/mmu.h>
743 #	define GETPAGESIZE() PAGESIZE	/* Is this still right? */
744 #   endif
745 #   ifdef AMIGA
746 #	define OS_TYPE "AMIGA"
747  	    	/* STACKBOTTOM and DATASTART handled specially	*/
748  	    	/* in os_dep.c					*/
749 # 	define DATAEND	/* not needed */
750 #	define GETPAGESIZE() 4096
751 #   endif
752 #   ifdef MACOS
753 #     ifndef __LOWMEM__
754 #     include <LowMem.h>
755 #     endif
756 #     define OS_TYPE "MACOS"
757 			/* see os_dep.c for details of global data segments. */
758 #     define STACKBOTTOM ((ptr_t) LMGetCurStackBase())
759 #     define DATAEND	/* not needed */
760 #     define GETPAGESIZE() 4096
761 #   endif
762 #   ifdef NEXT
763 #	define OS_TYPE "NEXT"
764 #	define DATASTART ((ptr_t) get_etext())
765 #	define STACKBOTTOM ((ptr_t) 0x4000000)
766 #	define DATAEND	/* not needed */
767 #   endif
768 # endif
769 
770 # if defined(POWERPC)
771 #   define MACH_TYPE "POWERPC"
772 #   ifdef MACOS
773 #     define ALIGNMENT 2  /* Still necessary?  Could it be 4?	*/
774 #     ifndef __LOWMEM__
775 #     include <LowMem.h>
776 #     endif
777 #     define OS_TYPE "MACOS"
778 			/* see os_dep.c for details of global data segments. */
779 #     define STACKBOTTOM ((ptr_t) LMGetCurStackBase())
780 #     define DATAEND  /* not needed */
781 #   endif
782 #   ifdef LINUX
783 #     if defined(__powerpc64__)
784 #       define ALIGNMENT 8
785 #       define CPP_WORDSZ 64
786 #       ifndef HBLKSIZE
787 #         define HBLKSIZE 4096
788 #       endif
789 #     else
790 #       define ALIGNMENT 4
791 #     endif
792 #     define OS_TYPE "LINUX"
793       /* HEURISTIC1 has been reliably reported to fail for a 32-bit	*/
794       /* executable on a 64 bit kernel.					*/
795 #     define LINUX_STACKBOTTOM
796 #     define DYNAMIC_LOADING
797 #     define SEARCH_FOR_DATA_START
798       extern int _end[];
799 #     define DATAEND (_end)
800 #   endif
801 #   ifdef DARWIN
802 #     define OS_TYPE "DARWIN"
803 #     define DYNAMIC_LOADING
804 #     if defined(__ppc64__)
805 #       define ALIGNMENT 8
806 #       define CPP_WORDSZ 64
807 #       define STACKBOTTOM ((ptr_t) 0x7fff5fc00000)
808 #       define CACHE_LINE_SIZE 64
809 #       ifndef HBLKSIZE
810 #         define HBLKSIZE 4096
811 #       endif
812 #     else
813 #       define ALIGNMENT 4
814 #       define STACKBOTTOM ((ptr_t) 0xc0000000)
815 #     endif
816       /* XXX: see get_end(3), get_etext() and get_end() should not be used.
817 	 These aren't used when dyld support is enabled (it is by default) */
818 #     define DATASTART ((ptr_t) get_etext())
819 #     define DATAEND	((ptr_t) get_end())
820 #     define USE_MMAP
821 #     define USE_MMAP_ANON
822 #     define USE_ASM_PUSH_REGS
823 #     ifdef GC_DARWIN_THREADS
824 #       define MPROTECT_VDB
825 #     endif
826 #     include <unistd.h>
827 #     define GETPAGESIZE() getpagesize()
828 #     if defined(USE_PPC_PREFETCH) && defined(__GNUC__)
829 	/* The performance impact of prefetches is untested */
830 #	define PREFETCH(x) \
831 	  __asm__ __volatile__ ("dcbt 0,%0" : : "r" ((const void *) (x)))
832 #	define PREFETCH_FOR_WRITE(x) \
833 	  __asm__ __volatile__ ("dcbtst 0,%0" : : "r" ((const void *) (x)))
834 #     endif
835       /* There seems to be some issues with trylock hanging on darwin. This
836 	 should be looked into some more */
837 #     define NO_PTHREAD_TRYLOCK
838 #   endif
839 #   ifdef FREEBSD
840 #   if defined(__powerpc64__)
841 #       define ALIGNMENT 8
842 #       define CPP_WORDSZ 64
843 #       ifndef HBLKSIZE
844 #           define HBLKSIZE 4096
845 #       endif
846 #   else
847 #       define ALIGNMENT 4
848 #   endif
849 #       define OS_TYPE "FREEBSD"
850 #       ifndef GC_FREEBSD_THREADS
851 #           define MPROTECT_VDB
852 #       endif
853 #       define SIG_SUSPEND SIGUSR1
854 #       define SIG_THR_RESTART SIGUSR2
855 #       define FREEBSD_STACKBOTTOM
856 #       ifdef __ELF__
857 #           define DYNAMIC_LOADING
858 #       endif
859         extern char etext[];
860         extern char * GC_FreeBSDGetDataStart();
861 #       define DATASTART GC_FreeBSDGetDataStart(0x1000, &etext)
862 #   endif
863 #   ifdef NETBSD
864 #     define ALIGNMENT 4
865 #     define OS_TYPE "NETBSD"
866 #     define HEURISTIC2
867       extern char etext[];
868 #     define DATASTART GC_data_start
869 #     define DYNAMIC_LOADING
870 #   endif
871 #   ifdef NOSYS
872 #     define ALIGNMENT 4
873 #     define OS_TYPE "NOSYS"
874       extern void __end[], __dso_handle[];
875 #     define DATASTART (__dso_handle)  /* OK, that's ugly.  */
876 #     define DATAEND (__end)
877 	/* Stack starts at 0xE0000000 for the simulator.  */
878 #     undef STACK_GRAN
879 #     define STACK_GRAN 0x10000000
880 #     define HEURISTIC1
881 #   endif
882 # endif
883 
884 # ifdef VAX
885 #   define MACH_TYPE "VAX"
886 #   define ALIGNMENT 4	/* Pointers are longword aligned by 4.2 C compiler */
887     extern char etext[];
888 #   define DATASTART ((ptr_t)(etext))
889 #   ifdef BSD
890 #	define OS_TYPE "BSD"
891 #	define HEURISTIC1
892 			/* HEURISTIC2 may be OK, but it's hard to test. */
893 #   endif
894 #   ifdef ULTRIX
895 #	define OS_TYPE "ULTRIX"
896 #	define STACKBOTTOM ((ptr_t) 0x7fffc800)
897 #   endif
898 # endif
899 
900 # ifdef RT
901 #   define MACH_TYPE "RT"
902 #   define ALIGNMENT 4
903 #   define DATASTART ((ptr_t) 0x10000000)
904 #   define STACKBOTTOM ((ptr_t) 0x1fffd800)
905 # endif
906 
907 # ifdef SPARC
908 #   define MACH_TYPE "SPARC"
909 #   if defined(__arch64__) || defined(__sparcv9)
910 #     define ALIGNMENT 8
911 #     define CPP_WORDSZ 64
912 #     define ELF_CLASS ELFCLASS64
913 #   else
914 #     define ALIGNMENT 4	/* Required by hardware	*/
915 #     define CPP_WORDSZ 32
916 #   endif
917 #   define ALIGN_DOUBLE
918 #   ifdef SUNOS5
919 #	define OS_TYPE "SUNOS5"
920 	extern int _etext[];
921 	extern int _end[];
922 	extern ptr_t GC_SysVGetDataStart();
923 #       define DATASTART GC_SysVGetDataStart(0x10000, _etext)
924 #	define DATAEND (_end)
925 #	if !defined(USE_MMAP) && defined(REDIRECT_MALLOC)
926 #	    define USE_MMAP
927 	    /* Otherwise we now use calloc.  Mmap may result in the	*/
928 	    /* heap interleaved with thread stacks, which can result in	*/
929 	    /* excessive blacklisting.  Sbrk is unusable since it	*/
930 	    /* doesn't interact correctly with the system malloc.	*/
931 #	endif
932 #       ifdef USE_MMAP
933 #         define HEAP_START (ptr_t)0x40000000
934 #       else
935 #	  define HEAP_START DATAEND
936 #       endif
937 #	define PROC_VDB
938 #	define SOLARIS_STACKBOTTOM
939 #	include <unistd.h>
940 #       define GETPAGESIZE()  sysconf(_SC_PAGESIZE)
941 		/* getpagesize() appeared to be missing from at least one */
942 		/* Solaris 5.4 installation.  Weird.			  */
943 #	define DYNAMIC_LOADING
944 #   endif
945 #   ifdef SUNOS4
946 #	define OS_TYPE "SUNOS4"
947 	/* [If you have a weak stomach, don't read this.]		*/
948 	/* We would like to use:					*/
949 /* #       define DATASTART ((ptr_t)((((word) (etext)) + 0x1fff) & ~0x1fff)) */
950 	/* This fails occasionally, due to an ancient, but very 	*/
951 	/* persistent ld bug.  etext is set 32 bytes too high.		*/
952 	/* We instead read the text segment size from the a.out		*/
953 	/* header, which happens to be mapped into our address space	*/
954 	/* at the start of the text segment.  The detective work here	*/
955 	/* was done by Robert Ehrlich, Manuel Serrano, and Bernard	*/
956 	/* Serpette of INRIA.						*/
957 	/* This assumes ZMAGIC, i.e. demand-loadable executables.	*/
958 #	define TEXTSTART 0x2000
959 #       define DATASTART ((ptr_t)(*(int *)(TEXTSTART+0x4)+TEXTSTART))
960 #	define MPROTECT_VDB
961 #	define HEURISTIC1
962 # 	define DYNAMIC_LOADING
963 #   endif
964 #   ifdef DRSNX
965 #	define OS_TYPE "DRSNX"
966 	extern ptr_t GC_SysVGetDataStart();
967 	extern int etext[];
968 #       define DATASTART GC_SysVGetDataStart(0x10000, etext)
969 #	define MPROTECT_VDB
970 #       define STACKBOTTOM ((ptr_t) 0xdfff0000)
971 #	define DYNAMIC_LOADING
972 #   endif
973 #   ifdef LINUX
974 #     define OS_TYPE "LINUX"
975 #     ifdef __ELF__
976 #       define DYNAMIC_LOADING
977 #     else
978           Linux Sparc/a.out not supported
979 #     endif
980       extern int _end[];
981       extern int _etext[];
982 #     define DATAEND (_end)
983 #     define SVR4
984       extern ptr_t GC_SysVGetDataStart();
985 #     ifdef __arch64__
986 #	define DATASTART GC_SysVGetDataStart(0x100000, _etext)
987 #     else
988 #       define DATASTART GC_SysVGetDataStart(0x10000, _etext)
989 #     endif
990 #     define LINUX_STACKBOTTOM
991 #   endif
992 #   ifdef OPENBSD
993 #     define OS_TYPE "OPENBSD"
994 #     define STACKBOTTOM ((ptr_t) 0xf8000000)
995       extern int etext[];
996 #     define DATASTART ((ptr_t)(etext))
997 #   endif
998 #   ifdef NETBSD
999 #     define OS_TYPE "NETBSD"
1000 #     define HEURISTIC2
1001 #     ifdef __ELF__
1002 #	define DATASTART GC_data_start
1003 #	define DYNAMIC_LOADING
1004 #     else
1005 	extern char etext[];
1006 #	define DATASTART ((ptr_t)(etext))
1007 #     endif
1008 #   endif
1009 #   ifdef FREEBSD
1010 #	define OS_TYPE "FREEBSD"
1011 #	define SIG_SUSPEND SIGUSR1
1012 #	define SIG_THR_RESTART SIGUSR2
1013 #	define FREEBSD_STACKBOTTOM
1014 #	ifdef __ELF__
1015 #	    define DYNAMIC_LOADING
1016 #	endif
1017 	extern char etext[];
1018 	extern char edata[];
1019 	extern char end[];
1020 #	define NEED_FIND_LIMIT
1021 #	define DATASTART ((ptr_t)(&etext))
1022 #	define DATAEND (GC_find_limit (DATASTART, TRUE))
1023 #	define DATASTART2 ((ptr_t)(&edata))
1024 #	define DATAEND2 ((ptr_t)(&end))
1025 #   endif
1026 # endif
1027 
1028 # ifdef I386
1029 #   define MACH_TYPE "I386"
1030 #   if defined(__LP64__) || defined(_WIN64)
1031 #     define CPP_WORDSZ 64
1032 #     define ALIGNMENT 8
1033 #   else
1034 #     define CPP_WORDSZ 32
1035 #     define ALIGNMENT 4
1036 			/* Appears to hold for all "32 bit" compilers	*/
1037 			/* except Borland.  The -a4 option fixes 	*/
1038 			/* Borland.					*/
1039                         /* Ivan Demakov: For Watcom the option is -zp4. */
1040 #   endif
1041 #   ifndef SMALL_CONFIG
1042 #     define ALIGN_DOUBLE /* Not strictly necessary, but may give speed   */
1043 			  /* improvement on Pentiums.			  */
1044 #   endif
1045 #   ifdef HAVE_BUILTIN_UNWIND_INIT
1046 #	define USE_GENERIC_PUSH_REGS
1047 #   endif
1048 #   ifdef SEQUENT
1049 #	define OS_TYPE "SEQUENT"
1050 	extern int etext[];
1051 #       define DATASTART ((ptr_t)((((word) (etext)) + 0xfff) & ~0xfff))
1052 #       define STACKBOTTOM ((ptr_t) 0x3ffff000)
1053 #   endif
1054 #   ifdef BEOS
1055 #     define OS_TYPE "BEOS"
1056 #     include <OS.h>
1057 #     define GETPAGESIZE() B_PAGE_SIZE
1058       extern int etext[];
1059 #     define DATASTART ((ptr_t)((((word) (etext)) + 0xfff) & ~0xfff))
1060 #   endif
1061 #   ifdef SUNOS5
1062 #	define OS_TYPE "SUNOS5"
1063         extern int _etext[], _end[];
1064   	extern ptr_t GC_SysVGetDataStart();
1065 #       define DATASTART GC_SysVGetDataStart(0x1000, _etext)
1066 #	define DATAEND (_end)
1067 #	define SOLARIS_STACKBOTTOM
1068 /* At least in Solaris 2.5, PROC_VDB gives wrong values for dirty bits. */
1069 /* It appears to be fixed in 2.8 and 2.9.				*/
1070 #	ifdef SOLARIS25_PROC_VDB_BUG_FIXED
1071 #	  define PROC_VDB
1072 #	endif
1073 #	define DYNAMIC_LOADING
1074 #	if !defined(USE_MMAP) && defined(REDIRECT_MALLOC)
1075 #	    define USE_MMAP
1076 	    /* Otherwise we now use calloc.  Mmap may result in the	*/
1077 	    /* heap interleaved with thread stacks, which can result in	*/
1078 	    /* excessive blacklisting.  Sbrk is unusable since it	*/
1079 	    /* doesn't interact correctly with the system malloc.	*/
1080 #	endif
1081 #       ifdef USE_MMAP
1082 #         define HEAP_START (ptr_t)0x40000000
1083 #       else
1084 #	  define HEAP_START DATAEND
1085 #       endif
1086 #   endif
1087 #   ifdef SCO
1088 #	define OS_TYPE "SCO"
1089 	extern int etext[];
1090 #   	define DATASTART ((ptr_t)((((word) (etext)) + 0x3fffff) \
1091 				  & ~0x3fffff) \
1092 				 +((word)etext & 0xfff))
1093 #	define STACKBOTTOM ((ptr_t) 0x7ffffffc)
1094 #   endif
1095 #   ifdef SCO_ELF
1096 #       define OS_TYPE "SCO_ELF"
1097         extern int etext[];
1098 #       define DATASTART ((ptr_t)(etext))
1099 #       define STACKBOTTOM ((ptr_t) 0x08048000)
1100 #       define DYNAMIC_LOADING
1101 #	define ELF_CLASS ELFCLASS32
1102 #   endif
1103 #   ifdef DGUX
1104 #	define OS_TYPE "DGUX"
1105 	extern int _etext, _end;
1106 	extern ptr_t GC_SysVGetDataStart();
1107 #	define DATASTART GC_SysVGetDataStart(0x1000, &_etext)
1108 #	define DATAEND (&_end)
1109 #	define STACK_GROWS_DOWN
1110 #	define HEURISTIC2
1111 #	include <unistd.h>
1112 #	define GETPAGESIZE()  sysconf(_SC_PAGESIZE)
1113 #	define DYNAMIC_LOADING
1114 #	ifndef USE_MMAP
1115 #	  define USE_MMAP
1116 #	endif /* USE_MMAP */
1117 #	define MAP_FAILED (void *) -1
1118 #	ifdef USE_MMAP
1119 #	  define HEAP_START (ptr_t)0x40000000
1120 #	else /* USE_MMAP */
1121 #	  define HEAP_START DATAEND
1122 #	endif /* USE_MMAP */
1123 #   endif /* DGUX */
1124 
1125 #   ifdef LINUX
1126 #	ifndef __GNUC__
1127 	  /* The Intel compiler doesn't like inline assembly */
1128 #	  define USE_GENERIC_PUSH_REGS
1129 # 	endif
1130 #	define OS_TYPE "LINUX"
1131 #       define LINUX_STACKBOTTOM
1132 #	if 0
1133 #	  define HEURISTIC1
1134 #         undef STACK_GRAN
1135 #         define STACK_GRAN 0x10000000
1136 	  /* STACKBOTTOM is usually 0xc0000000, but this changes with	*/
1137 	  /* different kernel configurations.  In particular, systems	*/
1138 	  /* with 2GB physical memory will usually move the user	*/
1139 	  /* address space limit, and hence initial SP to 0x80000000.	*/
1140 #       endif
1141 #       if !defined(GC_LINUX_THREADS) || !defined(REDIRECT_MALLOC)
1142 #	    define MPROTECT_VDB
1143 #	else
1144 	    /* We seem to get random errors in incremental mode,	*/
1145 	    /* possibly because Linux threads is itself a malloc client */
1146 	    /* and can't deal with the signals.				*/
1147 #	endif
1148 #	define HEAP_START (ptr_t)0x1000
1149 		/* This encourages mmap to give us low addresses,	*/
1150 		/* thus allowing the heap to grow to ~3GB		*/
1151 #       ifdef __ELF__
1152 #            define DYNAMIC_LOADING
1153 #	     ifdef UNDEFINED	/* includes ro data */
1154 	       extern int _etext[];
1155 #              define DATASTART ((ptr_t)((((word) (_etext)) + 0xfff) & ~0xfff))
1156 #	     endif
1157 #	     include <features.h>
1158 #	     if defined(__GLIBC__) && __GLIBC__ >= 2
1159 #		 define SEARCH_FOR_DATA_START
1160 #	     else
1161      	         extern char **__environ;
1162 #                define DATASTART ((ptr_t)(&__environ))
1163 			      /* hideous kludge: __environ is the first */
1164 			      /* word in crt0.o, and delimits the start */
1165 			      /* of the data segment, no matter which   */
1166 			      /* ld options were passed through.        */
1167 			      /* We could use _etext instead, but that  */
1168 			      /* would include .rodata, which may       */
1169 			      /* contain large read-only data tables    */
1170 			      /* that we'd rather not scan.		*/
1171 #	     endif
1172 	     extern int _end[];
1173 #	     define DATAEND (_end)
1174 #	else
1175 	     extern int etext[];
1176 #            define DATASTART ((ptr_t)((((word) (etext)) + 0xfff) & ~0xfff))
1177 #       endif
1178 #	ifdef USE_I686_PREFETCH
1179 	  /* FIXME: Thus should use __builtin_prefetch, but we'll leave that	*/
1180 	  /* for the next rtelease.						*/
1181 #	  define PREFETCH(x) \
1182 	    __asm__ __volatile__ ("	prefetchnta	%0": : "m"(*(char *)(x)))
1183 	    /* Empirically prefetcht0 is much more effective at reducing	*/
1184 	    /* cache miss stalls for the targetted load instructions.  But it	*/
1185 	    /* seems to interfere enough with other cache traffic that the net	*/
1186 	    /* result is worse than prefetchnta.				*/
1187 #         if 0
1188 	    /* Using prefetches for write seems to have a slight negative	*/
1189 	    /* impact on performance, at least for a PIII/500.			*/
1190 #	    define PREFETCH_FOR_WRITE(x) \
1191 	      __asm__ __volatile__ ("	prefetcht0	%0": : "m"(*(char *)(x)))
1192 #	  endif
1193 #	endif
1194 #	ifdef USE_3DNOW_PREFETCH
1195 #	  define PREFETCH(x) \
1196 	    __asm__ __volatile__ ("	prefetch	%0": : "m"(*(char *)(x)))
1197 #	  define PREFETCH_FOR_WRITE(x) \
1198 	    __asm__ __volatile__ ("	prefetchw	%0": : "m"(*(char *)(x)))
1199 #	endif
1200 #   endif
1201 #   ifdef CYGWIN32
1202 #       define OS_TYPE "CYGWIN32"
1203 #       define DATASTART ((ptr_t)GC_DATASTART)  /* From gc.h */
1204 #       define DATAEND	 ((ptr_t)GC_DATAEND)
1205 #	undef STACK_GRAN
1206 #       define STACK_GRAN 0x10000
1207 #       define HEURISTIC1
1208 #   endif
1209 #   ifdef OS2
1210 #	define OS_TYPE "OS2"
1211  	    	/* STACKBOTTOM and DATASTART are handled specially in 	*/
1212 		/* os_dep.c. OS2 actually has the right			*/
1213 		/* system call!						*/
1214 #	define DATAEND	/* not needed */
1215 #	define USE_GENERIC_PUSH_REGS
1216 #   endif
1217 #   ifdef MSWIN32
1218 #	define OS_TYPE "MSWIN32"
1219 		/* STACKBOTTOM and DATASTART are handled specially in 	*/
1220 		/* os_dep.c.						*/
1221 #       ifndef __WATCOMC__
1222 #	  define MPROTECT_VDB
1223 #	endif
1224 #       define DATAEND  /* not needed */
1225 #   endif
1226 #   ifdef MSWINCE
1227 #	define OS_TYPE "MSWINCE"
1228 #       define DATAEND  /* not needed */
1229 #   endif
1230 #   ifdef DJGPP
1231 #       define OS_TYPE "DJGPP"
1232 #       include "stubinfo.h"
1233         extern int etext[];
1234         extern int _stklen;
1235         extern int __djgpp_stack_limit;
1236 #       define DATASTART ((ptr_t)((((word) (etext)) + 0x1ff) & ~0x1ff))
1237 /* #       define STACKBOTTOM ((ptr_t)((word) _stubinfo + _stubinfo->size \
1238                                                      + _stklen)) */
1239 #       define STACKBOTTOM ((ptr_t)((word) __djgpp_stack_limit + _stklen))
1240 		/* This may not be right.  */
1241 #   endif
1242 #   ifdef OPENBSD
1243 #	define OS_TYPE "OPENBSD"
1244 #   endif
1245 #   ifdef FREEBSD
1246 #	define OS_TYPE "FREEBSD"
1247 #	ifndef GC_FREEBSD_THREADS
1248 #	    define MPROTECT_VDB
1249 #	endif
1250 #	ifdef __GLIBC__
1251 #	    define SIG_SUSPEND		(32+6)
1252 #	    define SIG_THR_RESTART	(32+5)
1253 	    extern int _end[];
1254 #	    define DATAEND (_end)
1255 #	else
1256 #	    define SIG_SUSPEND SIGUSR1
1257 #	    define SIG_THR_RESTART SIGUSR2
1258 #	endif
1259 #	define FREEBSD_STACKBOTTOM
1260 #	ifdef __ELF__
1261 #	    define DYNAMIC_LOADING
1262 #	endif
1263 	extern char etext[];
1264 	extern char * GC_FreeBSDGetDataStart();
1265 #	define DATASTART GC_FreeBSDGetDataStart(0x1000, &etext)
1266 #   endif
1267 #   ifdef NETBSD
1268 #	define OS_TYPE "NETBSD"
1269 #	ifdef __ELF__
1270 #	    define DYNAMIC_LOADING
1271 #	endif
1272 #   endif
1273 #   ifdef THREE86BSD
1274 #	define OS_TYPE "THREE86BSD"
1275 #   endif
1276 #   ifdef BSDI
1277 #	define OS_TYPE "BSDI"
1278 #   endif
1279 #   if defined(OPENBSD) || defined(NETBSD) \
1280         || defined(THREE86BSD) || defined(BSDI)
1281 #	define HEURISTIC2
1282 	extern char etext[];
1283 #	define DATASTART ((ptr_t)(etext))
1284 #   endif
1285 #   ifdef NEXT
1286 #	define OS_TYPE "NEXT"
1287 #	define DATASTART ((ptr_t) get_etext())
1288 #	define STACKBOTTOM ((ptr_t)0xc0000000)
1289 #	define DATAEND	/* not needed */
1290 #   endif
1291 #   ifdef DOS4GW
1292 #     define OS_TYPE "DOS4GW"
1293       extern long __nullarea;
1294       extern char _end;
1295       extern char *_STACKTOP;
1296       /* Depending on calling conventions Watcom C either precedes
1297          or does not precedes with undescore names of C-variables.
1298          Make sure startup code variables always have the same names.  */
1299       #pragma aux __nullarea "*";
1300       #pragma aux _end "*";
1301 #     define STACKBOTTOM ((ptr_t) _STACKTOP)
1302                          /* confused? me too. */
1303 #     define DATASTART ((ptr_t) &__nullarea)
1304 #     define DATAEND ((ptr_t) &_end)
1305 #   endif
1306 #   ifdef HURD
1307 #     define OS_TYPE "HURD"
1308 #     define STACK_GROWS_DOWN
1309 #     define HEURISTIC2
1310 #     define SIG_SUSPEND SIGUSR1
1311 #     define SIG_THR_RESTART SIGUSR2
1312 #     define SEARCH_FOR_DATA_START
1313       extern int   _end[];
1314 #     define DATAEND ( (ptr_t) (_end))
1315 /* #     define MPROTECT_VDB  Not quite working yet? */
1316 #     define DYNAMIC_LOADING
1317 #   endif
1318 #   ifdef DARWIN
1319 #     define OS_TYPE "DARWIN"
1320 #     define DARWIN_DONT_PARSE_STACK
1321 #     define DYNAMIC_LOADING
1322       /* XXX: see get_end(3), get_etext() and get_end() should not be used.
1323 	 These aren't used when dyld support is enabled (it is by default) */
1324 #     define DATASTART ((ptr_t) get_etext())
1325 #     define DATAEND	((ptr_t) get_end())
1326 #     ifdef HAVE_PTHREAD_GET_STACKADDR_NP
1327 #       define STACKBOTTOM (ptr_t)pthread_get_stackaddr_np(pthread_self())
1328 #     else
1329 #       define STACKBOTTOM ((ptr_t) 0xc0000000)
1330 #     endif
1331 #     define USE_MMAP
1332 #     define USE_MMAP_ANON
1333 #     define USE_ASM_PUSH_REGS
1334 #     ifdef GC_DARWIN_THREADS
1335 #       define MPROTECT_VDB
1336 #     endif
1337 #     include <unistd.h>
1338 #     define GETPAGESIZE() getpagesize()
1339       /* There seems to be some issues with trylock hanging on darwin. This
1340 	 should be looked into some more */
1341 #     define NO_PTHREAD_TRYLOCK
1342 #   endif /* DARWIN */
1343 # endif
1344 
1345 # ifdef NS32K
1346 #   define MACH_TYPE "NS32K"
1347 #   define ALIGNMENT 4
1348     extern char **environ;
1349 #   define DATASTART ((ptr_t)(&environ))
1350 			      /* hideous kludge: environ is the first   */
1351 			      /* word in crt0.o, and delimits the start */
1352 			      /* of the data segment, no matter which   */
1353 			      /* ld options were passed through.        */
1354 #   define STACKBOTTOM ((ptr_t) 0xfffff000) /* for Encore */
1355 # endif
1356 
1357 # ifdef MIPS
1358 #   define MACH_TYPE "MIPS"
1359 #   ifdef LINUX
1360       /* This was developed for a linuxce style platform.  Probably	*/
1361       /* needs to be tweaked for workstation class machines.		*/
1362 #     define OS_TYPE "LINUX"
1363 #     define DYNAMIC_LOADING
1364       extern int _end[];
1365 #     define DATAEND (_end)
1366       extern int __data_start[];
1367 #     define DATASTART ((ptr_t)(__data_start))
1368 #     ifdef _MIPS_SZPTR
1369 #	define CPP_WORDSZ _MIPS_SZPTR
1370 #	define ALIGNMENT (_MIPS_SZPTR/8)
1371 #     else
1372 #	define ALIGNMENT 4
1373 #     endif
1374 #     ifndef HBLKSIZE
1375 #       define HBLKSIZE 4096
1376 #     endif
1377 #     define USE_GENERIC_PUSH_REGS
1378 #     if __GLIBC__ == 2 && __GLIBC_MINOR__ >= 2 || __GLIBC__ > 2
1379 #        define LINUX_STACKBOTTOM
1380 #     else
1381 #        define STACKBOTTOM 0x80000000
1382 #     endif
1383 #   endif /* Linux */
1384 #   ifdef EWS4800
1385 #      define HEURISTIC2
1386 #      if defined(_MIPS_SZPTR) && (_MIPS_SZPTR == 64)
1387          extern int _fdata[], _end[];
1388 #        define DATASTART ((ptr_t)_fdata)
1389 #        define DATAEND ((ptr_t)_end)
1390 #        define CPP_WORDSZ _MIPS_SZPTR
1391 #        define ALIGNMENT (_MIPS_SZPTR/8)
1392 #      else
1393          extern int etext[], edata[], end[];
1394          extern int _DYNAMIC_LINKING[], _gp[];
1395 #        define DATASTART ((ptr_t)((((word)etext + 0x3ffff) & ~0x3ffff) \
1396                + ((word)etext & 0xffff)))
1397 #        define DATAEND (edata)
1398 #        define DATASTART2 (_DYNAMIC_LINKING \
1399                ? (ptr_t)(((word)_gp + 0x8000 + 0x3ffff) & ~0x3ffff) \
1400                : (ptr_t)edata)
1401 #        define DATAEND2 (end)
1402 #        define ALIGNMENT 4
1403 #      endif
1404 #      define OS_TYPE "EWS4800"
1405 #      define USE_GENERIC_PUSH_REGS 1
1406 #   endif
1407 #   ifdef ULTRIX
1408 #	define HEURISTIC2
1409 #       define DATASTART (ptr_t)0x10000000
1410 			      /* Could probably be slightly higher since */
1411 			      /* startup code allocates lots of stuff.   */
1412 #	define OS_TYPE "ULTRIX"
1413 #       define ALIGNMENT 4
1414 #   endif
1415 #   ifdef RISCOS
1416 #	define HEURISTIC2
1417 #       define DATASTART (ptr_t)0x10000000
1418 #	define OS_TYPE "RISCOS"
1419 #   	define ALIGNMENT 4  /* Required by hardware */
1420 #   endif
1421 #   ifdef IRIX5
1422 #	define HEURISTIC2
1423         extern int _fdata[];
1424 #       define DATASTART ((ptr_t)(_fdata))
1425 #       ifdef USE_MMAP
1426 #         define HEAP_START (ptr_t)0x30000000
1427 #       else
1428 #	  define HEAP_START DATASTART
1429 #       endif
1430 			      /* Lowest plausible heap address.		*/
1431 			      /* In the MMAP case, we map there.	*/
1432 			      /* In either case it is used to identify	*/
1433 			      /* heap sections so they're not 		*/
1434 			      /* considered as roots.			*/
1435 #	define OS_TYPE "IRIX5"
1436 /*#       define MPROTECT_VDB DOB: this should work, but there is evidence */
1437 /* 	  	of recent breakage.					   */
1438 #       ifdef _MIPS_SZPTR
1439 #	  define CPP_WORDSZ _MIPS_SZPTR
1440 #	  define ALIGNMENT (_MIPS_SZPTR/8)
1441 #	  if CPP_WORDSZ != 64
1442 #	    define ALIGN_DOUBLE
1443 #	  endif
1444 #	  if _MIPS_SZPTR == 64
1445 #	    define ELF_CLASS ELFCLASS64
1446 #	  endif
1447 #	else
1448 #         define ALIGNMENT 4
1449 #	  define ALIGN_DOUBLE
1450 #	endif
1451 #	define DYNAMIC_LOADING
1452 #   endif
1453 #   ifdef MSWINCE
1454 #       define OS_TYPE "MSWINCE"
1455 #       define ALIGNMENT 4
1456 #       define DATAEND /* not needed */
1457 #   endif
1458 #   if defined(NETBSD)
1459 #     define ALIGNMENT 4
1460 #     define OS_TYPE "NETBSD"
1461 #     define HEURISTIC2
1462 #     define USE_GENERIC_PUSH_REGS
1463 #     ifdef __ELF__
1464         extern int etext[];
1465 #       define DATASTART GC_data_start
1466 #       define NEED_FIND_LIMIT
1467 #       define DYNAMIC_LOADING
1468 #     else
1469 #       define DATASTART ((ptr_t) 0x10000000)
1470 #       define STACKBOTTOM ((ptr_t) 0x7ffff000)
1471 #     endif /* _ELF_ */
1472 #  endif
1473 # endif
1474 
1475 # ifdef RS6000
1476 #   define MACH_TYPE "RS6000"
1477 #   ifdef ALIGNMENT
1478 #     undef ALIGNMENT
1479 #   endif
1480 #   ifdef IA64
1481 #     undef IA64 /* DOB: some AIX installs stupidly define IA64 in /usr/include/sys/systemcfg.h */
1482 #   endif
1483 #   ifdef __64BIT__
1484 #     define ALIGNMENT 8
1485 #     define CPP_WORDSZ 64
1486 #     define STACKBOTTOM ((ptr_t)0x1000000000000000)
1487 #   else
1488 #     define ALIGNMENT 4
1489 #     define CPP_WORDSZ 32
1490 #     define STACKBOTTOM ((ptr_t)((ulong)&errno))
1491 #   endif
1492 #   define USE_MMAP
1493 #   define USE_MMAP_ANON
1494  /* From AIX linker man page:
1495  _text Specifies the first location of the program.
1496  _etext Specifies the first location after the program.
1497  _data Specifies the first location of the data.
1498  _edata Specifies the first location after the initialized data
1499  _end or end Specifies the first location after all data.
1500  */
1501     extern int _data[], _end[];
1502 #   define DATASTART ((ptr_t)((ulong)_data))
1503 #   define DATAEND ((ptr_t)((ulong)_end))
1504     extern int errno;
1505 #   define USE_GENERIC_PUSH_REGS
1506 #   define DYNAMIC_LOADING
1507 	/* For really old versions of AIX, this may have to be removed. */
1508 # endif
1509 
1510 # ifdef HP_PA
1511 #   define MACH_TYPE "HP_PA"
1512 #   ifdef __LP64__
1513 #     define CPP_WORDSZ 64
1514 #     define ALIGNMENT 8
1515 #   else
1516 #     define CPP_WORDSZ 32
1517 #     define ALIGNMENT 4
1518 #     define ALIGN_DOUBLE
1519 #   endif
1520 #   if !defined(GC_HPUX_THREADS) && !defined(GC_LINUX_THREADS)
1521 #     ifndef LINUX /* For now. */
1522 #       define MPROTECT_VDB
1523 #     endif
1524 #   else
1525 #     define GENERIC_COMPARE_AND_SWAP
1526 	/* No compare-and-swap instruction.  Use pthread mutexes 	*/
1527 	/* when we absolutely have to.					*/
1528 #     ifdef PARALLEL_MARK
1529 #	define USE_MARK_BYTES
1530 		/* Minimize compare-and-swap usage.		*/
1531 #     endif
1532 #   endif
1533 #   define STACK_GROWS_UP
1534 #   ifdef HPUX
1535 #     define OS_TYPE "HPUX"
1536       extern int __data_start[];
1537 #     define DATASTART ((ptr_t)(__data_start))
1538 #     if 0
1539 	/* The following appears to work for 7xx systems running HP/UX	*/
1540 	/* 9.xx Furthermore, it might result in much faster		*/
1541 	/* collections than HEURISTIC2, which may involve scanning	*/
1542 	/* segments that directly precede the stack.  It is not the	*/
1543 	/* default, since it may not work on older machine/OS		*/
1544 	/* combinations. (Thanks to Raymond X.T. Nijssen for uncovering	*/
1545 	/* this.)							*/
1546 #       define STACKBOTTOM ((ptr_t) 0x7b033000)  /* from /etc/conf/h/param.h */
1547 #     else
1548 	/* Gustavo Rodriguez-Rivera suggested changing HEURISTIC2	*/
1549 	/* to this.  Note that the GC must be initialized before the	*/
1550     	/* first putenv call.						*/
1551 	extern char ** environ;
1552 #       define STACKBOTTOM ((ptr_t)environ)
1553 #     endif
1554 #     define DYNAMIC_LOADING
1555 #     include <unistd.h>
1556 #     define GETPAGESIZE() sysconf(_SC_PAGE_SIZE)
1557 #     ifndef __GNUC__
1558 #       define PREFETCH(x)  { \
1559                               register long addr = (long)(x); \
1560                               (void) _asm ("LDW", 0, 0, addr, 0); \
1561                             }
1562 #     endif
1563 #   endif /* HPUX */
1564 #   ifdef LINUX
1565 #     define OS_TYPE "LINUX"
1566 #     define LINUX_STACKBOTTOM
1567 #     define DYNAMIC_LOADING
1568 #     define SEARCH_FOR_DATA_START
1569       extern int _end[];
1570 #     define DATAEND (&_end)
1571 #   endif /* LINUX */
1572 # endif /* HP_PA */
1573 
1574 # ifdef ALPHA
1575 #   define MACH_TYPE "ALPHA"
1576 #   define ALIGNMENT 8
1577 #   define CPP_WORDSZ 64
1578 #   ifndef LINUX
1579 #     define USE_GENERIC_PUSH_REGS
1580       /* Gcc and probably the DEC/Compaq compiler spill pointers to preserved */
1581       /* fp registers in some cases when the target is a 21264.  The assembly */
1582       /* code doesn't handle that yet, and version dependencies make that a   */
1583       /* bit tricky.  Do the easy thing for now.				    */
1584 #   endif
1585 #   ifdef NETBSD
1586 #	define OS_TYPE "NETBSD"
1587 #	define HEURISTIC2
1588 #	define DATASTART GC_data_start
1589 #	define ELFCLASS32 32
1590 #	define ELFCLASS64 64
1591 #	define ELF_CLASS ELFCLASS64
1592 #       define DYNAMIC_LOADING
1593 #   endif
1594 #   ifdef OPENBSD
1595 #	define OS_TYPE "OPENBSD"
1596 #	define HEURISTIC2
1597 #   	ifdef __ELF__	/* since OpenBSD/Alpha 2.9 */
1598 #	   define DATASTART GC_data_start
1599 #   	   define ELFCLASS32 32
1600 #   	   define ELFCLASS64 64
1601 #   	   define ELF_CLASS ELFCLASS64
1602 #       else		/* ECOFF, until OpenBSD/Alpha 2.7 */
1603 #   	   define DATASTART ((ptr_t) 0x140000000)
1604 #   	endif
1605 #   endif
1606 #   ifdef FREEBSD
1607 #	define OS_TYPE "FREEBSD"
1608 /* MPROTECT_VDB is not yet supported at all on FreeBSD/alpha. */
1609 #	define SIG_SUSPEND SIGUSR1
1610 #	define SIG_THR_RESTART SIGUSR2
1611 #	define FREEBSD_STACKBOTTOM
1612 #	ifdef __ELF__
1613 #	    define DYNAMIC_LOADING
1614 #	endif
1615 /* Handle unmapped hole alpha*-*-freebsd[45]* puts between etext and edata. */
1616 	extern char etext[];
1617 	extern char edata[];
1618 	extern char end[];
1619 #	define NEED_FIND_LIMIT
1620 #	define DATASTART ((ptr_t)(&etext))
1621 #	define DATAEND (GC_find_limit (DATASTART, TRUE))
1622 #	define DATASTART2 ((ptr_t)(&edata))
1623 #	define DATAEND2 ((ptr_t)(&end))
1624 #   endif
1625 #   ifdef OSF1
1626 #	define OS_TYPE "OSF1"
1627 #   	define DATASTART ((ptr_t) 0x140000000)
1628 	extern int _end[];
1629 #   	define DATAEND ((ptr_t) &_end)
1630  	extern char ** environ;
1631 	/* round up from the value of environ to the nearest page boundary */
1632 	/* Probably breaks if putenv is called before collector 	   */
1633 	/* initialization.						   */
1634 #	define STACKBOTTOM ((ptr_t)(((word)(environ) | (getpagesize()-1))+1))
1635 /* #   	define HEURISTIC2 */
1636 	/* Normally HEURISTIC2 is too conervative, since		*/
1637 	/* the text segment immediately follows the stack.		*/
1638 	/* Hence we give an upper pound.				*/
1639 	/* This is currently unused, since we disabled HEURISTIC2	*/
1640     	extern int __start[];
1641 #   	define HEURISTIC2_LIMIT ((ptr_t)((word)(__start) & ~(getpagesize()-1)))
1642 #	ifndef GC_OSF1_THREADS
1643 	  /* Unresolved signal issues with threads.	*/
1644 #   	  define MPROTECT_VDB
1645 #       endif
1646 #   	define DYNAMIC_LOADING
1647 #   endif
1648 #   ifdef LINUX
1649 #       define OS_TYPE "LINUX"
1650 #       define LINUX_STACKBOTTOM
1651 #       ifdef __ELF__
1652 #	  define SEARCH_FOR_DATA_START
1653 #         define DYNAMIC_LOADING
1654 #       else
1655 #           define DATASTART ((ptr_t) 0x140000000)
1656 #       endif
1657 	extern int _end[];
1658 #	define DATAEND (_end)
1659 #	define MPROTECT_VDB
1660 		/* Has only been superficially tested.  May not	*/
1661 		/* work on all versions.			*/
1662 #   endif
1663 # endif
1664 
1665 # ifdef IA64
1666 #   define MACH_TYPE "IA64"
1667 #   define USE_GENERIC_PUSH_REGS
1668 	/* We need to get preserved registers in addition to register   */
1669 	/* windows.   That's easiest to do with setjmp.			*/
1670 #   ifdef PARALLEL_MARK
1671 #	define USE_MARK_BYTES
1672 	    /* Compare-and-exchange is too expensive to use for 	*/
1673 	    /* setting mark bits.					*/
1674 #   endif
1675 #   ifdef HPUX
1676 #	ifdef _ILP32
1677 #	  define CPP_WORDSZ 32
1678 #         define ALIGN_DOUBLE
1679 	    /* Requires 8 byte alignment for malloc */
1680 #   	  define ALIGNMENT 4
1681 #       else
1682 #	  ifndef _LP64
1683 		---> unknown ABI
1684 #         endif
1685 #	  define CPP_WORDSZ 64
1686 #   	  define ALIGN_DOUBLE
1687 	    /* Requires 16 byte alignment for malloc */
1688 #         define ALIGNMENT 8
1689 #       endif
1690 #       define OS_TYPE "HPUX"
1691         extern int __data_start[];
1692 #       define DATASTART ((ptr_t)(__data_start))
1693         /* Gustavo Rodriguez-Rivera suggested changing HEURISTIC2	*/
1694         /* to this.  Note that the GC must be initialized before the	*/
1695     	/* first putenv call.						*/
1696 	extern char ** environ;
1697 #       define STACKBOTTOM ((ptr_t)environ)
1698 #       define HPUX_STACKBOTTOM
1699 #       define DYNAMIC_LOADING
1700 #       include <unistd.h>
1701 #       define GETPAGESIZE() sysconf(_SC_PAGE_SIZE)
1702  	/* The following was empirically determined, and is probably	*/
1703 	/* not very robust.						*/
1704 	/* Note that the backing store base seems to be at a nice 	*/
1705 	/* address minus one page.					*/
1706 #	define BACKING_STORE_DISPLACEMENT 0x1000000
1707 #	define BACKING_STORE_ALIGNMENT 0x1000
1708 	extern ptr_t GC_register_stackbottom;
1709 #	define BACKING_STORE_BASE GC_register_stackbottom
1710 	/* Known to be wrong for recent HP/UX versions!!!	*/
1711 #   endif
1712 #   ifdef LINUX
1713 #   	define CPP_WORDSZ 64
1714 #   	define ALIGN_DOUBLE
1715 	  /* Requires 16 byte alignment for malloc */
1716 #   	define ALIGNMENT 8
1717 #       define OS_TYPE "LINUX"
1718 	/* The following works on NUE and older kernels:	*/
1719 /* #       define STACKBOTTOM ((ptr_t) 0xa000000000000000l)	*/
1720 	/* This does not work on NUE:				*/
1721 #       define LINUX_STACKBOTTOM
1722 	/* We also need the base address of the register stack	*/
1723 	/* backing store.  This is computed in 			*/
1724 	/* GC_linux_register_stack_base based on the following	*/
1725 	/* constants:						*/
1726 #       define BACKING_STORE_ALIGNMENT 0x100000
1727 #       define BACKING_STORE_DISPLACEMENT 0x80000000
1728 	extern ptr_t GC_register_stackbottom;
1729 #	define BACKING_STORE_BASE GC_register_stackbottom
1730 #	define SEARCH_FOR_DATA_START
1731 #	ifdef __GNUC__
1732 #         define DYNAMIC_LOADING
1733 #	else
1734 	  /* In the Intel compiler environment, we seem to end up with  */
1735 	  /* statically linked executables and an undefined reference	*/
1736 	  /* to _DYNAMIC						*/
1737 #  	endif
1738 #	define MPROTECT_VDB
1739 		/* Requires Linux 2.3.47 or later.	*/
1740 	extern int _end[];
1741 #	define DATAEND (_end)
1742 #       ifdef __GNUC__
1743 #	  ifndef __INTEL_COMPILER
1744 #	    define PREFETCH(x) \
1745 	      __asm__ ("	lfetch	[%0]": : "r"(x))
1746 #	    define PREFETCH_FOR_WRITE(x) \
1747 	      __asm__ ("	lfetch.excl	[%0]": : "r"(x))
1748 #	    define CLEAR_DOUBLE(x) \
1749 	      __asm__ ("	stf.spill	[%0]=f0": : "r"((void *)(x)))
1750 #	  else
1751 #           include <ia64intrin.h>
1752 #	    define PREFETCH(x) \
1753 	      __lfetch(__lfhint_none, (x))
1754 #	    define PREFETCH_FOR_WRITE(x) \
1755 	      __lfetch(__lfhint_nta,  (x))
1756 #	    define CLEAR_DOUBLE(x) \
1757 	      __stf_spill((void *)(x), 0)
1758 #	  endif // __INTEL_COMPILER
1759 #       endif
1760 #   endif
1761 #   ifdef MSWIN32
1762       /* FIXME: This is a very partial guess.  There is no port, yet.	*/
1763 #     define OS_TYPE "MSWIN32"
1764 		/* STACKBOTTOM and DATASTART are handled specially in 	*/
1765 		/* os_dep.c.						*/
1766 #     define DATAEND  /* not needed */
1767 #     if defined(_WIN64)
1768 #       define CPP_WORDSZ 64
1769 #     else
1770 #       define CPP_WORDSZ 32   /* Is this possible?	*/
1771 #     endif
1772 #     define ALIGNMENT 8
1773 #   endif
1774 # endif
1775 
1776 # ifdef M88K
1777 #   define MACH_TYPE "M88K"
1778 #   define ALIGNMENT 4
1779 #   define ALIGN_DOUBLE
1780     extern int etext[];
1781 #   ifdef CX_UX
1782 #	define OS_TYPE "CX_UX"
1783 #       define DATASTART ((((word)etext + 0x3fffff) & ~0x3fffff) + 0x10000)
1784 #   endif
1785 #   ifdef  DGUX
1786 #	define OS_TYPE "DGUX"
1787 	extern ptr_t GC_SysVGetDataStart();
1788 #       define DATASTART GC_SysVGetDataStart(0x10000, etext)
1789 #   endif
1790 #   define STACKBOTTOM ((char*)0xf0000000) /* determined empirically */
1791 # endif
1792 
1793 # ifdef S370
1794     /* If this still works, and if anyone cares, this should probably	*/
1795     /* be moved to the S390 category.					*/
1796 #   define MACH_TYPE "S370"
1797 #   define ALIGNMENT 4	/* Required by hardware	*/
1798 #   define USE_GENERIC_PUSH_REGS
1799 #   ifdef UTS4
1800 #       define OS_TYPE "UTS4"
1801 	extern int etext[];
1802 	extern int _etext[];
1803 	extern int _end[];
1804 	extern ptr_t GC_SysVGetDataStart();
1805 #       define DATASTART GC_SysVGetDataStart(0x10000, _etext)
1806 #	define DATAEND (_end)
1807 #	define HEURISTIC2
1808 #   endif
1809 # endif
1810 
1811 # ifdef S390
1812 #   define MACH_TYPE "S390"
1813 #   define USE_GENERIC_PUSH_REGS
1814 #   ifndef __s390x__
1815 #     define ALIGNMENT 4
1816 #     define CPP_WORDSZ 32
1817 #   else
1818 #     define ALIGNMENT 8
1819 #     define CPP_WORDSZ 64
1820 #   endif
1821 #   ifndef HBLKSIZE
1822 #     define HBLKSIZE 4096
1823 #   endif
1824 #   ifdef LINUX
1825 #       define OS_TYPE "LINUX"
1826 #       define LINUX_STACKBOTTOM
1827 #       define DYNAMIC_LOADING
1828 	extern int __data_start[];
1829 #       define DATASTART ((ptr_t)(__data_start))
1830     extern int _end[];
1831 #   define DATAEND (_end)
1832 #   define CACHE_LINE_SIZE 256
1833 #   define GETPAGESIZE() 4096
1834 #   endif
1835 # endif
1836 
1837 # if defined(PJ)
1838 #   define ALIGNMENT 4
1839     extern int _etext[];
1840 #   define DATASTART ((ptr_t)(_etext))
1841 #   define HEURISTIC1
1842 # endif
1843 
1844 # ifdef ARM32
1845 #   define CPP_WORDSZ 32
1846 #   define MACH_TYPE "ARM32"
1847 #   define ALIGNMENT 4
1848 #   ifdef NETBSD
1849 #       define OS_TYPE "NETBSD"
1850 #       define HEURISTIC2
1851 #	ifdef __ELF__
1852 #          define DATASTART GC_data_start
1853 #	   define DYNAMIC_LOADING
1854 #	else
1855            extern char etext[];
1856 #          define DATASTART ((ptr_t)(etext))
1857 #	endif
1858 #       define USE_GENERIC_PUSH_REGS
1859 #   endif
1860 #   ifdef LINUX
1861 #       define OS_TYPE "LINUX"
1862 #       define LINUX_STACKBOTTOM
1863 #       undef STACK_GRAN
1864 #       define STACK_GRAN 0x10000000
1865 #       define USE_GENERIC_PUSH_REGS
1866 #       ifdef __ELF__
1867 #            define DYNAMIC_LOADING
1868 #	     include <features.h>
1869 #	     if defined(__GLIBC__) && __GLIBC__ >= 2
1870 #		 define SEARCH_FOR_DATA_START
1871 #	     else
1872      	         extern char **__environ;
1873 #                define DATASTART ((ptr_t)(&__environ))
1874 			      /* hideous kludge: __environ is the first */
1875 			      /* word in crt0.o, and delimits the start */
1876 			      /* of the data segment, no matter which   */
1877 			      /* ld options were passed through.        */
1878 			      /* We could use _etext instead, but that  */
1879 			      /* would include .rodata, which may       */
1880 			      /* contain large read-only data tables    */
1881 			      /* that we'd rather not scan.		*/
1882 #	     endif
1883 	     extern int _end[];
1884 #	     define DATAEND (_end)
1885 #	else
1886 	     extern int etext[];
1887 #            define DATASTART ((ptr_t)((((word) (etext)) + 0xfff) & ~0xfff))
1888 #       endif
1889 #   endif
1890 #   ifdef MSWINCE
1891 #     define OS_TYPE "MSWINCE"
1892 #     define DATAEND /* not needed */
1893 #   endif
1894 #   ifdef NOSYS
1895       /* __data_start is usually defined in the target linker script.  */
1896       extern int __data_start[];
1897 #     define DATASTART (ptr_t)(__data_start)
1898 #     define USE_GENERIC_PUSH_REGS
1899       /* __stack_base__ is set in newlib/libc/sys/arm/crt0.S  */
1900       extern void *__stack_base__;
1901 #     define STACKBOTTOM ((ptr_t) (__stack_base__))
1902 #   endif
1903 #endif
1904 
1905 # ifdef CRIS
1906 #   define MACH_TYPE "CRIS"
1907 #   define CPP_WORDSZ 32
1908 #   define ALIGNMENT 1
1909 #   define OS_TYPE "LINUX"
1910 #   define DYNAMIC_LOADING
1911 #   define LINUX_STACKBOTTOM
1912 #   define USE_GENERIC_PUSH_REGS
1913 #   define SEARCH_FOR_DATA_START
1914       extern int _end[];
1915 #   define DATAEND (_end)
1916 # endif
1917 
1918 # ifdef SH
1919 #   define MACH_TYPE "SH"
1920 #   define ALIGNMENT 4
1921 #   ifdef MSWINCE
1922 #     define OS_TYPE "MSWINCE"
1923 #     define DATAEND /* not needed */
1924 #   endif
1925 #   ifdef LINUX
1926 #     define OS_TYPE "LINUX"
1927 #     define LINUX_STACKBOTTOM
1928 #     define USE_GENERIC_PUSH_REGS
1929 #     define DYNAMIC_LOADING
1930 #     define SEARCH_FOR_DATA_START
1931       extern int _end[];
1932 #     define DATAEND (_end)
1933 #   endif
1934 #   ifdef NETBSD
1935 #      define OS_TYPE "NETBSD"
1936 #      define HEURISTIC2
1937 #      define DATASTART GC_data_start
1938 #       define USE_GENERIC_PUSH_REGS
1939 #      define DYNAMIC_LOADING
1940 #   endif
1941 # endif
1942 
1943 # ifdef SH4
1944 #   define MACH_TYPE "SH4"
1945 #   define OS_TYPE "MSWINCE"
1946 #   define ALIGNMENT 4
1947 #   define DATAEND /* not needed */
1948 # endif
1949 
1950 # ifdef M32R
1951 #   define CPP_WORDSZ 32
1952 #   define MACH_TYPE "M32R"
1953 #   define ALIGNMENT 4
1954 #   ifdef LINUX
1955 #     define OS_TYPE "LINUX"
1956 #     define LINUX_STACKBOTTOM
1957 #     undef STACK_GRAN
1958 #     define STACK_GRAN 0x10000000
1959 #     define USE_GENERIC_PUSH_REGS
1960 #     define DYNAMIC_LOADING
1961 #     define SEARCH_FOR_DATA_START
1962       extern int _end[];
1963 #     define DATAEND (_end)
1964 #   endif
1965 # endif
1966 
1967 # ifdef X86_64
1968 #   define MACH_TYPE "X86_64"
1969 #   ifdef __ILP32__
1970 #     define ALIGNMENT 4
1971 #     define CPP_WORDSZ 32
1972 #   else
1973 #     define ALIGNMENT 8
1974 #     define CPP_WORDSZ 64
1975 #   endif
1976 #   ifndef HBLKSIZE
1977 #     define HBLKSIZE 4096
1978 #   endif
1979 #   define CACHE_LINE_SIZE 64
1980 #   define USE_GENERIC_PUSH_REGS
1981 #   ifdef LINUX
1982 #	define OS_TYPE "LINUX"
1983 #       define LINUX_STACKBOTTOM
1984 #       if !defined(GC_LINUX_THREADS) || !defined(REDIRECT_MALLOC)
1985 #	    define MPROTECT_VDB
1986 #	else
1987 	    /* We seem to get random errors in incremental mode,	*/
1988 	    /* possibly because Linux threads is itself a malloc client */
1989 	    /* and can't deal with the signals.				*/
1990 #	endif
1991 #       ifdef __ELF__
1992 #            define DYNAMIC_LOADING
1993 #	     ifdef UNDEFINED	/* includes ro data */
1994 	       extern int _etext[];
1995 #              define DATASTART ((ptr_t)((((word) (_etext)) + 0xfff) & ~0xfff))
1996 #	     endif
1997 #	     include <features.h>
1998 #	     define SEARCH_FOR_DATA_START
1999 	     extern int _end[];
2000 #	     define DATAEND (_end)
2001 #	else
2002 	     extern int etext[];
2003 #            define DATASTART ((ptr_t)((((word) (etext)) + 0xfff) & ~0xfff))
2004 #       endif
2005 #       if defined(__GNUC__) && __GNUC >= 3
2006 #	    define PREFETCH(x) __builtin_prefetch((x), 0, 0)
2007 #	    define PREFETCH_FOR_WRITE(x) __builtin_prefetch((x), 1)
2008 #	endif
2009 #   endif
2010 #   ifdef DARWIN
2011 #     define OS_TYPE "DARWIN"
2012 #     define DARWIN_DONT_PARSE_STACK
2013 #     define DYNAMIC_LOADING
2014       /* XXX: see get_end(3), get_etext() and get_end() should not be used.
2015 	 These aren't used when dyld support is enabled (it is by default) */
2016 #     define DATASTART ((ptr_t) get_etext())
2017 #     define DATAEND	((ptr_t) get_end())
2018 #     ifdef HAVE_PTHREAD_GET_STACKADDR_NP
2019 #       define STACKBOTTOM (ptr_t)pthread_get_stackaddr_np(pthread_self())
2020 #     else
2021 #       define STACKBOTTOM ((ptr_t) 0x7fff5fc00000)
2022 #     endif
2023 #     define USE_MMAP
2024 #     define USE_MMAP_ANON
2025 #     ifdef GC_DARWIN_THREADS
2026 #       define MPROTECT_VDB
2027 #     endif
2028 #     include <unistd.h>
2029 #     define GETPAGESIZE() getpagesize()
2030       /* There seems to be some issues with trylock hanging on darwin. This
2031 	 should be looked into some more */
2032 #     define NO_PTHREAD_TRYLOCK
2033 #   endif
2034 #   ifdef FREEBSD
2035 #	define OS_TYPE "FREEBSD"
2036 #	ifndef GC_FREEBSD_THREADS
2037 #	    define MPROTECT_VDB
2038 #	endif
2039 #	ifdef __GLIBC__
2040 #	    define SIG_SUSPEND		(32+6)
2041 #	    define SIG_THR_RESTART	(32+5)
2042 	    extern int _end[];
2043 #	    define DATAEND (_end)
2044 #	else
2045 #	    define SIG_SUSPEND SIGUSR1
2046 #	    define SIG_THR_RESTART SIGUSR2
2047 #	endif
2048 #	define FREEBSD_STACKBOTTOM
2049 #	ifdef __ELF__
2050 #	    define DYNAMIC_LOADING
2051 #	endif
2052 	extern char etext[];
2053 	extern char * GC_FreeBSDGetDataStart();
2054 #	define DATASTART GC_FreeBSDGetDataStart(0x1000, &etext)
2055 #   endif
2056 #   ifdef NETBSD
2057 #	define OS_TYPE "NETBSD"
2058 #	ifdef __ELF__
2059 #	    define DYNAMIC_LOADING
2060 #	endif
2061 #	define HEURISTIC2
2062 	extern char etext[];
2063 #	define SEARCH_FOR_DATA_START
2064 #   endif
2065 #   ifdef SUNOS5
2066 #	define ELF_CLASS ELFCLASS64
2067 #	define OS_TYPE "SUNOS5"
2068         extern int _etext[], _end[];
2069   	extern ptr_t GC_SysVGetDataStart();
2070 #       define DATASTART GC_SysVGetDataStart(0x1000, _etext)
2071 #	define DATAEND (_end)
2072 /*	# define STACKBOTTOM ((ptr_t)(_start)) worked through 2.7,  	*/
2073 /*      but reportedly breaks under 2.8.  It appears that the stack	*/
2074 /* 	base is a property of the executable, so this should not break	*/
2075 /* 	old executables.						*/
2076 /*  	HEURISTIC2 probably works, but this appears to be preferable.	*/
2077 /* #       include <sys/vm.h> */
2078 /* #	define STACKBOTTOM USRSTACK */
2079 #	define HEURISTIC2
2080 #	define PROC_VDB
2081 #	define DYNAMIC_LOADING
2082 #	if !defined(USE_MMAP) && defined(REDIRECT_MALLOC)
2083 #	    define USE_MMAP
2084 	    /* Otherwise we now use calloc.  Mmap may result in the	*/
2085 	    /* heap interleaved with thread stacks, which can result in	*/
2086 	    /* excessive blacklisting.  Sbrk is unusable since it	*/
2087 	    /* doesn't interact correctly with the system malloc.	*/
2088 #	endif
2089 #       ifdef USE_MMAP
2090 #         define HEAP_START (ptr_t)0x40000000
2091 #       else
2092 #	  define HEAP_START DATAEND
2093 #       endif
2094 #   endif
2095 # endif
2096 
2097 #if defined(LINUX) && defined(USE_MMAP)
2098     /* The kernel may do a somewhat better job merging mappings etc.	*/
2099     /* with anonymous mappings.						*/
2100 #   define USE_MMAP_ANON
2101 #endif
2102 
2103 #if defined(LINUX) && defined(REDIRECT_MALLOC)
2104     /* Rld appears to allocate some memory with its own allocator, and	*/
2105     /* some through malloc, which might be redirected.  To make this	*/
2106     /* work with collectable memory, we have to scan memory allocated	*/
2107     /* by rld's internal malloc.					*/
2108 #   define USE_PROC_FOR_LIBRARIES
2109 #endif
2110 
2111 # ifndef STACK_GROWS_UP
2112 #   define STACK_GROWS_DOWN
2113 # endif
2114 
2115 # ifndef CPP_WORDSZ
2116 #   define CPP_WORDSZ 32
2117 # endif
2118 
2119 # ifndef OS_TYPE
2120 #   define OS_TYPE ""
2121 # endif
2122 
2123 # ifndef DATAEND
2124     extern int end[];
2125 #   define DATAEND (end)
2126 # endif
2127 
2128 # if defined(SVR4) && !defined(GETPAGESIZE)
2129 #    include <unistd.h>
2130 #    define GETPAGESIZE()  sysconf(_SC_PAGESIZE)
2131 # endif
2132 
2133 # ifndef GETPAGESIZE
2134 #   if defined(SUNOS5) || defined(IRIX5)
2135 #	include <unistd.h>
2136 #   endif
2137 #   define GETPAGESIZE() getpagesize()
2138 # endif
2139 
2140 # if defined(SUNOS5) || defined(DRSNX) || defined(UTS4)
2141 	    /* OS has SVR4 generic features.  Probably others also qualify.	*/
2142 #   define SVR4
2143 # endif
2144 
2145 # if defined(SUNOS5) || defined(DRSNX)
2146 	    /* OS has SUNOS5 style semi-undocumented interface to dynamic 	*/
2147 	    /* loader.								*/
2148 #   define SUNOS5DL
2149 	    /* OS has SUNOS5 style signal handlers.				*/
2150 #   define SUNOS5SIGS
2151 # endif
2152 
2153 # if defined(HPUX)
2154 #   define SUNOS5SIGS
2155 # endif
2156 
2157 # if defined(FREEBSD) && ((__FreeBSD__ >= 4) || (__FreeBSD_kernel__ >= 4))
2158 #   define SUNOS5SIGS
2159 # endif
2160 
2161 # if defined(SVR4) || defined(LINUX) || defined(IRIX5) || defined(HPUX) \
2162 	    || defined(OPENBSD) || defined(NETBSD) || defined(FREEBSD) \
2163 	    || defined(DGUX) || defined(BSD) || defined(SUNOS4) \
2164 	    || defined(_AIX) || defined(DARWIN) || defined(OSF1) \
2165 	    || defined(HURD)
2166 #   define UNIX_LIKE   /* Basic Unix-like system calls work.	*/
2167 # endif
2168 
2169 # if CPP_WORDSZ != 32 && CPP_WORDSZ != 64
2170 	   -> bad word size
2171 # endif
2172 
2173 # ifdef PCR
2174 #   undef DYNAMIC_LOADING
2175 #   undef STACKBOTTOM
2176 #   undef HEURISTIC1
2177 #   undef HEURISTIC2
2178 #   undef PROC_VDB
2179 #   undef MPROTECT_VDB
2180 #   define PCR_VDB
2181 # endif
2182 
2183 # ifdef SRC_M3
2184 	/* Postponed for now. */
2185 #   undef PROC_VDB
2186 #   undef MPROTECT_VDB
2187 # endif
2188 
2189 # ifdef SMALL_CONFIG
2190 	/* Presumably not worth the space it takes. */
2191 #   undef PROC_VDB
2192 #   undef MPROTECT_VDB
2193 # endif
2194 
2195 # ifdef USE_MUNMAP
2196 #   undef MPROTECT_VDB  /* Can't deal with address space holes. */
2197 # endif
2198 
2199 # ifdef PARALLEL_MARK
2200 #   undef MPROTECT_VDB  /* For now.	*/
2201 # endif
2202 
2203 # if !defined(PCR_VDB) && !defined(PROC_VDB) && !defined(MPROTECT_VDB)
2204 #   define DEFAULT_VDB
2205 # endif
2206 
2207 # ifndef PREFETCH
2208 #   define PREFETCH(x)
2209 #   define NO_PREFETCH
2210 # endif
2211 
2212 # ifndef PREFETCH_FOR_WRITE
2213 #   define PREFETCH_FOR_WRITE(x)
2214 #   define NO_PREFETCH_FOR_WRITE
2215 # endif
2216 
2217 # ifndef CACHE_LINE_SIZE
2218 #   define CACHE_LINE_SIZE 32	/* Wild guess	*/
2219 # endif
2220 
2221 # if defined(LINUX) || defined(HURD) || defined(__GLIBC__)
2222 #   define REGISTER_LIBRARIES_EARLY
2223     /* We sometimes use dl_iterate_phdr, which may acquire an internal	*/
2224     /* lock.  This isn't safe after the world has stopped.  So we must	*/
2225     /* call GC_register_dynamic_libraries before stopping the world.	*/
2226     /* For performance reasons, this may be beneficial on other		*/
2227     /* platforms as well, though it should be avoided in win32.		*/
2228 # endif /* LINUX */
2229 
2230 # if defined(SEARCH_FOR_DATA_START)
2231     extern ptr_t GC_data_start;
2232 #   define DATASTART GC_data_start
2233 # endif
2234 
2235 # ifndef CLEAR_DOUBLE
2236 #   define CLEAR_DOUBLE(x) \
2237 		((word*)x)[0] = 0; \
2238 		((word*)x)[1] = 0;
2239 # endif /* CLEAR_DOUBLE */
2240 
2241 # if defined(GC_IRIX_THREADS) && !defined(IRIX5)
2242 	--> inconsistent configuration
2243 # endif
2244 # if defined(GC_LINUX_THREADS) && !defined(LINUX)
2245 	--> inconsistent configuration
2246 # endif
2247 # if defined(GC_SOLARIS_THREADS) && !defined(SUNOS5)
2248 	--> inconsistent configuration
2249 # endif
2250 # if defined(GC_HPUX_THREADS) && !defined(HPUX)
2251 	--> inconsistent configuration
2252 # endif
2253 # if defined(GC_AIX_THREADS) && !defined(_AIX)
2254 	--> inconsistent configuration
2255 # endif
2256 # if defined(GC_GNU_THREADS) && !defined(HURD)
2257 	--> inconsistent configuration
2258 # endif
2259 # if defined(GC_WIN32_THREADS) && !defined(MSWIN32) && !defined(CYGWIN32)
2260 	--> inconsistent configuration
2261 # endif
2262 
2263 # if defined(PCR) || defined(SRC_M3) || \
2264 		defined(GC_SOLARIS_THREADS) || defined(GC_WIN32_THREADS) || \
2265 		defined(GC_PTHREADS)
2266 #   define THREADS
2267 # endif
2268 
2269 # if defined(HP_PA) || defined(M88K) \
2270              || defined(POWERPC) && !defined(DARWIN) \
2271 	     || defined(LINT) || defined(MSWINCE) || defined(ARM32) || defined(CRIS) \
2272 	     || (defined(I386) && defined(__LCC__))
2273 	/* Use setjmp based hack to mark from callee-save registers.    */
2274 	/* The define should move to the individual platform 		*/
2275 	/* descriptions.						*/
2276 #	define USE_GENERIC_PUSH_REGS
2277 # endif
2278 
2279 # if defined(MSWINCE)
2280 #   define NO_GETENV
2281 # endif
2282 
2283 # if defined(SPARC)
2284 #   define ASM_CLEAR_CODE	/* Stack clearing is crucial, and we 	*/
2285 				/* include assembly code to do it well.	*/
2286 # endif
2287 
2288   /* Can we save call chain in objects for debugging?   	        */
2289   /* SET NFRAMES (# of saved frames) and NARGS (#of args for each 	*/
2290   /* frame) to reasonable values for the platform.			*/
2291   /* Set SAVE_CALL_CHAIN if we can.  SAVE_CALL_COUNT can be specified 	*/
2292   /* at build time, though we feel free to adjust it slightly.		*/
2293   /* Define NEED_CALLINFO if we either save the call stack or 		*/
2294   /* GC_ADD_CALLER is defined.						*/
2295   /* GC_CAN_SAVE_CALL_STACKS is set in gc.h.				*/
2296 
2297 #if defined(SPARC)
2298 # define CAN_SAVE_CALL_ARGS
2299 #endif
2300 #if (defined(I386) || defined(X86_64)) && (defined(LINUX) || defined(__GLIBC__))
2301 	    /* SAVE_CALL_CHAIN is supported if the code is compiled to save	*/
2302 	    /* frame pointers by default, i.e. no -fomit-frame-pointer flag.	*/
2303 # define CAN_SAVE_CALL_ARGS
2304 #endif
2305 
2306 # if defined(SAVE_CALL_COUNT) && !defined(GC_ADD_CALLER) \
2307 	     && defined(GC_CAN_SAVE_CALL_STACKS)
2308 #   define SAVE_CALL_CHAIN
2309 # endif
2310 # ifdef SAVE_CALL_CHAIN
2311 #   if defined(SAVE_CALL_NARGS) && defined(CAN_SAVE_CALL_ARGS)
2312 #     define NARGS SAVE_CALL_NARGS
2313 #   else
2314 #     define NARGS 0	/* Number of arguments to save for each call.	*/
2315 #   endif
2316 # endif
2317 # ifdef SAVE_CALL_CHAIN
2318 #   ifndef SAVE_CALL_COUNT
2319 #     define NFRAMES 6	/* Number of frames to save. Even for		*/
2320 				/* alignment reasons.				*/
2321 #   else
2322 #     define NFRAMES ((SAVE_CALL_COUNT + 1) & ~1)
2323 #   endif
2324 #   define NEED_CALLINFO
2325 # endif /* SAVE_CALL_CHAIN */
2326 # ifdef GC_ADD_CALLER
2327 #   define NFRAMES 1
2328 #   define NARGS 0
2329 #   define NEED_CALLINFO
2330 # endif
2331 
2332 # if defined(MAKE_BACK_GRAPH) && !defined(DBG_HDRS_ALL)
2333 #   define DBG_HDRS_ALL
2334 # endif
2335 
2336 # if defined(POINTER_MASK) && !defined(POINTER_SHIFT)
2337 #   define POINTER_SHIFT 0
2338 # endif
2339 
2340 # if defined(POINTER_SHIFT) && !defined(POINTER_MASK)
2341 #   define POINTER_MASK ((GC_word)(-1))
2342 # endif
2343 
2344 # if !defined(FIXUP_POINTER) && defined(POINTER_MASK)
2345 #   define FIXUP_POINTER(p) (p) = ((p) & (POINTER_MASK) << POINTER_SHIFT)
2346 # endif
2347 
2348 # if defined(FIXUP_POINTER)
2349 #   define NEED_FIXUP_POINTER 1
2350 # else
2351 #   define NEED_FIXUP_POINTER 0
2352 #   define FIXUP_POINTER(p)
2353 # endif
2354 
2355 #ifdef GC_PRIVATE_H
2356 	/* This relies on some type definitions from gc_priv.h, from	*/
2357         /* where it's normally included.				*/
2358 	/*								*/
2359 	/* How to get heap memory from the OS:				*/
2360 	/* Note that sbrk()-like allocation is preferred, since it 	*/
2361 	/* usually makes it possible to merge consecutively allocated	*/
2362 	/* chunks.  It also avoids unintented recursion with		*/
2363 	/* -DREDIRECT_MALLOC.						*/
2364 	/* GET_MEM() returns a HLKSIZE aligned chunk.			*/
2365 	/* 0 is taken to mean failure. 					*/
2366 	/* In the case os USE_MMAP, the argument must also be a 	*/
2367 	/* physical page size.						*/
2368 	/* GET_MEM is currently not assumed to retrieve 0 filled space, */
2369 	/* though we should perhaps take advantage of the case in which */
2370 	/* does.							*/
2371 	struct hblk;	/* See gc_priv.h.	*/
2372 # ifdef PCR
2373 	    char * real_malloc();
2374 #   define GET_MEM(bytes) HBLKPTR(real_malloc((size_t)bytes + GC_page_size) \
2375 					  + GC_page_size-1)
2376 # else
2377 #   ifdef OS2
2378 	      void * os2_alloc(size_t bytes);
2379 #     define GET_MEM(bytes) HBLKPTR((ptr_t)os2_alloc((size_t)bytes \
2380 					    + GC_page_size) \
2381 					    + GC_page_size-1)
2382 #   else
2383 #     if defined(NEXT) || defined(DOS4GW) || \
2384 		 (defined(AMIGA) && !defined(GC_AMIGA_FASTALLOC)) || \
2385 		 (defined(SUNOS5) && !defined(USE_MMAP))
2386 #       define GET_MEM(bytes) HBLKPTR((size_t) \
2387 					      calloc(1, (size_t)bytes + GC_page_size) \
2388 					      + GC_page_size-1)
2389 #     else
2390 #	if defined(MSWIN32) || defined(CYGWIN32)
2391 	  extern ptr_t GC_win32_get_mem();
2392 #         define GET_MEM(bytes) (struct hblk *)GC_win32_get_mem(bytes)
2393 #	else
2394 #	  ifdef MACOS
2395 #	    if defined(USE_TEMPORARY_MEMORY)
2396 			extern Ptr GC_MacTemporaryNewPtr(size_t size,
2397 							 Boolean clearMemory);
2398 #               define GET_MEM(bytes) HBLKPTR( \
2399 			    GC_MacTemporaryNewPtr(bytes + GC_page_size, true) \
2400 			    + GC_page_size-1)
2401 #	    else
2402 #         	    define GET_MEM(bytes) HBLKPTR( \
2403 				NewPtrClear(bytes + GC_page_size) + GC_page_size-1)
2404 #	    endif
2405 #	  else
2406 #	    ifdef MSWINCE
2407 	      extern ptr_t GC_wince_get_mem();
2408 #	      define GET_MEM(bytes) (struct hblk *)GC_wince_get_mem(bytes)
2409 #	    else
2410 #	      if defined(AMIGA) && defined(GC_AMIGA_FASTALLOC)
2411 			extern void *GC_amiga_get_mem(size_t size);
2412 #		define GET_MEM(bytes) HBLKPTR((size_t) \
2413 			  GC_amiga_get_mem((size_t)bytes + GC_page_size) \
2414 			  + GC_page_size-1)
2415 #	      else
2416 		extern ptr_t GC_unix_get_mem();
2417 #               define GET_MEM(bytes) (struct hblk *)GC_unix_get_mem(bytes)
2418 #	      endif
2419 #	    endif
2420 #	  endif
2421 #	endif
2422 #     endif
2423 #   endif
2424 # endif
2425 
2426 #endif /* GC_PRIVATE_H */
2427 
2428 #if defined(_AIX) && !defined(__GNUC__) && !defined(__STDC__)
2429   /* IBMs xlc compiler doesn't appear to follow the convention of	*/
2430   /* defining  __STDC__ to be zero in extended mode.			*/
2431 #   define __STDC__ 0
2432 #endif
2433 
2434 # endif /* GCCONFIG_H */
2435