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-rw-r--r--gc/setjmp_t.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/gc/setjmp_t.c b/gc/setjmp_t.c
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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.
+ */
+/* Boehm, September 21, 1995 5:39 pm PDT */
+
+/* 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 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.) */
+#include <stdio.h>
+#include <setjmp.h>
+#include <string.h>
+#include "gcconfig.h"
+
+#ifdef OS2
+/* GETPAGESIZE() is set to getpagesize() by default, but that */
+/* doesn't really exist, and the collector doesn't need it. */
+#define INCL_DOSFILEMGR
+#define INCL_DOSMISC
+#define INCL_DOSERRORS
+#include <os2.h>
+
+int
+getpagesize()
+{
+ 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]));
+}
+#endif
+
+struct {char a_a; char * a_b;} a;
+
+int * nested_sp()
+{
+ int dummy;
+
+ return(&dummy);
+}
+
+main()
+{
+ int dummy;
+ long ps = GETPAGESIZE();
+ jmp_buf b;
+ register int x = (int)strlen("a"); /* 1, slightly disguised */
+ static int y = 0;
+
+ printf("This appears to be a %s running %s\n", MACH_TYPE, OS_TYPE);
+ if (nested_sp() < &dummy) {
+ 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)(&dummy) + ps) & ~(ps-1));
+ } else {
+ printf("Stack appears to grow up.\n");
+ printf("Define STACK_GROWS_UP in gc_private.h\n");
+ printf("A good guess for STACKBOTTOM on this machine is 0x%lx.\n",
+ ((unsigned long)(&dummy) + 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 %ld.\n",
+ (unsigned long)(&(a.a_b))-(unsigned long)(&a));
+
+ /* Encourage the compiler to keep x in a callee-save register */
+ x = 2*x-1;
+ printf("");
+ x = 2*x-1;
+ setjmp(b);
+ if (y == 1) {
+ if (x == 2) {
+ printf("Generic mark_regs code probably wont work\n");
+# if defined(SPARC) || defined(RS6000) || defined(VAX) || defined(MIPS) || defined(M68K) || defined(I386) || defined(NS32K) || defined(RT)
+ printf("Assembly code supplied\n");
+# else
+ printf("Need assembly code\n");
+# endif
+ } else if (x == 1) {
+ printf("Generic mark_regs code may work\n");
+ } else {
+ printf("Very strange setjmp implementation\n");
+ }
+ }
+ y++;
+ x = 2;
+ if (y == 1) longjmp(b,1);
+ return(0);
+}
+
+int g(x)
+int x;
+{
+ return(x);
+}