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/*
* Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*/
/* Check whether setjmp actually saves registers in jmp_buf. */
/* If it doesn't, the generic mark_regs code won't work. */
/* Compilers vary as to whether they will put x in a */
/* (callee-save) register without -O. The code is */
/* contrived such that any decent compiler should put x in */
/* a callee-save register with -O. Thus it is */
/* recommended that this be run optimized. (If the machine */
/* has no callee-save registers, then the generic code is */
/* safe, but this will not be noticed by this piece of */
/* code.) This test appears to be far from perfect. */
#include <stdio.h>
#include <setjmp.h>
#include <string.h>
#include "private/gc_priv.h"
#ifdef OS2
# define INCL_DOSERRORS
# define INCL_DOSFILEMGR
# define INCL_DOSMISC
# include <os2.h>
/* Similar to that in os_dep.c but use fprintf() to report a failure. */
/* GETPAGESIZE() macro is defined to os2_getpagesize(). */
static int os2_getpagesize(void)
{
ULONG result[1];
if (DosQuerySysInfo(QSV_PAGE_SIZE, QSV_PAGE_SIZE,
(void *)result, sizeof(ULONG)) != NO_ERROR) {
fprintf(stderr, "DosQuerySysInfo failed\n");
result[0] = 4096;
}
return (int)result[0];
}
#elif defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32)
static int win32_getpagesize(void)
{
SYSTEM_INFO sysinfo;
GetSystemInfo(&sysinfo);
return sysinfo.dwPageSize;
}
# define GETPAGESIZE() win32_getpagesize()
#endif
struct a_s {
char a_a;
char * a_b;
} a;
word nested_sp(void)
{
# if GC_GNUC_PREREQ(4, 0)
return (word)__builtin_frame_address(0);
# else
volatile word sp;
sp = (word)(&sp);
return sp;
# endif
}
/* To prevent nested_sp inlining. */
word (*volatile nested_sp_fn)(void) = nested_sp;
int g(int x);
#if defined(CPPCHECK) || !defined(__cplusplus)
const char *a_str = "a";
#else
# define a_str "a"
#endif
int main(void)
{
volatile word sp;
unsigned ps = GETPAGESIZE();
JMP_BUF b;
# if !defined(__cplusplus) || __cplusplus < 201703L /* before c++17 */
register
# endif
int x = (int)strlen(a_str); /* 1, slightly disguised */
static volatile int y = 0;
sp = (word)(&sp);
printf("This appears to be a %s running %s\n", MACH_TYPE, OS_TYPE);
# if defined(CPPCHECK)
(void)nested_sp(); /* to workaround a bug in cppcheck */
# endif
if (nested_sp_fn() < sp) {
printf("Stack appears to grow down, which is the default.\n");
printf("A good guess for STACKBOTTOM on this machine is 0x%lx.\n",
((unsigned long)sp + ps) & ~(ps-1));
} else {
printf("Stack appears to grow up.\n");
printf("Define STACK_GROWS_UP in gc_priv.h\n");
printf("A good guess for STACKBOTTOM on this machine is 0x%lx.\n",
((unsigned long)sp + ps) & ~(ps-1));
}
printf("Note that this may vary between machines of ostensibly\n");
printf("the same architecture (e.g. Sun 3/50s and 3/80s).\n");
printf("On many machines the value is not fixed.\n");
printf("A good guess for ALIGNMENT on this machine is %lu.\n",
(unsigned long)((word)(&(a.a_b)) - (word)(&a)));
printf("The following is a very dubious test of one root marking"
" strategy.\n");
printf("Results may not be accurate/useful:\n");
/* Encourage the compiler to keep x in a callee-save register */
x = 2*x-1;
printf("\n");
x = 2*x-1;
(void)SETJMP(b);
if (y == 1) {
if (x == 2) {
printf("setjmp-based generic mark_regs code probably won't work.\n");
printf("But we rarely try that anymore. If you have getcontect()\n");
printf("this probably doesn't matter.\n");
} else if (x == 1) {
printf("setjmp-based register marking code may work.\n");
} else {
printf("Very strange setjmp implementation.\n");
}
}
y++;
x = 2;
if (y == 1) LONGJMP(b, 1);
printf("Some GC internal configuration stuff: \n");
printf("\tWORDSZ = %lu, ALIGNMENT = %d, GC_GRANULE_BYTES = %d\n",
(unsigned long)WORDSZ, ALIGNMENT, GC_GRANULE_BYTES);
printf("\tUsing one mark ");
# if defined(USE_MARK_BYTES)
printf("byte");
# else
printf("bit");
# endif
printf(" per ");
# if defined(MARK_BIT_PER_OBJ)
printf("object.\n");
# elif defined(MARK_BIT_PER_GRANULE)
printf("granule.\n");
# endif
# ifdef THREAD_LOCAL_ALLOC
printf("Thread local allocation enabled.\n");
# endif
# ifdef PARALLEL_MARK
printf("Parallel marking enabled.\n");
# endif
(void)g(x);
return 0;
}
int g(int x)
{
return x;
}
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