ceph/src/boost/tools/build/src/engine/boehm_gc/setjmp_t.c

   1 /*
   2  * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
   3  *
   4  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   5  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
   6  *
   7  * Permission is hereby granted to use or copy this program
   8  * for any purpose,  provided the above notices are retained on all copies.
   9  * Permission to modify the code and to distribute modified code is granted,
  10  * provided the above notices are retained, and a notice that the code was
  11  * modified is included with the above copyright notice.
  12  */
  13
  14 /* Check whether setjmp actually saves registers in jmp_buf. */
  15 /* If it doesn't, the generic mark_regs code won't work.     */
  16 /* Compilers vary as to whether they will put x in a         */
  17 /* (callee-save) register without -O.  The code is           */
  18 /* contrived such that any decent compiler should put x in   */
  19 /* a callee-save register with -O.  Thus it is is            */
  20 /* recommended that this be run optimized.  (If the machine  */
  21 /* has no callee-save registers, then the generic code is    */
  22 /* safe, but this will not be noticed by this piece of       */
  23 /* code.)  This test appears to be far from perfect.         */
  24 #include <stdio.h>
  25 #include <setjmp.h>
  26 #include <string.h>
  27 #include "private/gc_priv.h"
  28
  29 #ifdef OS2
  30 /* GETPAGESIZE() is set to getpagesize() by default, but that   */
  31 /* doesn't really exist, and the collector doesn't need it.     */
  32 #define INCL_DOSFILEMGR
  33 #define INCL_DOSMISC
  34 #define INCL_DOSERRORS
  35 #include <os2.h>
  36
  37 int
  38 getpagesize()
  39 {
  40     ULONG result[1];
  41
  42     if (DosQuerySysInfo(QSV_PAGE_SIZE, QSV_PAGE_SIZE,
  43                         (void *)result, sizeof(ULONG)) != NO_ERROR) {
  44         fprintf(stderr, "DosQuerySysInfo failed\n");
  45         result[0] = 4096;
  46     }
  47     return((int)(result[0]));
  48 }
  49 #endif
  50
  51 struct {char a_a; char * a_b;} a;
  52
  53 int * nested_sp()
  54 {
  55     int dummy;
  56
  57     return(&dummy);
  58 }
  59
  60 int main()
  61 {
  62         int dummy;
  63         long ps = GETPAGESIZE();
  64         jmp_buf b;
  65         register int x = (int)strlen("a");  /* 1, slightly disguised */
  66         static int y = 0;
  67
  68         printf("This appears to be a %s running %s\n", MACH_TYPE, OS_TYPE);
  69         if (nested_sp() < &dummy) {
  70           printf("Stack appears to grow down, which is the default.\n");
  71           printf("A good guess for STACKBOTTOM on this machine is 0x%lx.\n",
  72                  ((unsigned long)(&dummy) + ps) & ~(ps-1));
  73         } else {
  74           printf("Stack appears to grow up.\n");
  75           printf("Define STACK_GROWS_UP in gc_private.h\n");
  76           printf("A good guess for STACKBOTTOM on this machine is 0x%lx.\n",
  77                  ((unsigned long)(&dummy) + ps) & ~(ps-1));
  78         }
  79         printf("Note that this may vary between machines of ostensibly\n");
  80         printf("the same architecture (e.g. Sun 3/50s and 3/80s).\n");
  81         printf("On many machines the value is not fixed.\n");
  82         printf("A good guess for ALIGNMENT on this machine is %ld.\n",
  83                (unsigned long)(&(a.a_b))-(unsigned long)(&a));
  84
  85         printf("The following is a very dubious test of one root marking"
  86                " strategy.\n");
  87         printf("Results may not be accurate/useful:\n");
  88         /* Encourage the compiler to keep x in a callee-save register */
  89         x = 2*x-1;
  90         printf("");
  91         x = 2*x-1;
  92         setjmp(b);
  93         if (y == 1) {
  94             if (x == 2) {
  95                 printf("Setjmp-based generic mark_regs code probably wont work.\n");
  96                 printf("But we rarely try that anymore.  If you have getcontect()\n");
  97                 printf("this probably doesn't matter.\n");
  98             } else if (x == 1) {
  99                 printf("Setjmp-based register marking code may work.\n");
 100             } else {
 101                 printf("Very strange setjmp implementation.\n");
 102             }
 103         }
 104         y++;
 105         x = 2;
 106         if (y == 1) longjmp(b,1);
 107         printf("Some GC internal configuration stuff: \n");
 108         printf("\tWORDSZ = %d, ALIGNMENT = %d, GC_GRANULE_BYTES = %d\n",
 109                WORDSZ, ALIGNMENT, GC_GRANULE_BYTES);
 110         printf("\tUsing one mark ");
 111 #       if defined(USE_MARK_BYTES)
 112           printf("byte");
 113 #       elif defined(USE_MARK_BITS)
 114           printf("bit");
 115 #       endif
 116         printf(" per ");
 117 #       if defined(MARK_BIT_PER_OBJ)
 118           printf("object.\n");
 119 #       elif defined(MARK_BIT_PER_GRANULE)
 120           printf("granule.\n");
 121 #       endif
 122 #       ifdef THREAD_LOCAL_ALLOC
 123           printf("Thread local allocation enabled.\n");
 124 #       endif
 125 #       ifdef PARALLEL_MARK
 126           printf("Parallel marking enabled.\n");
 127 #       endif
 128         return(0);
 129 }
 130
 131 int g(x)
 132 int x;
 133 {
 134         return(x);
 135 }